Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/namei.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * Some corrections by tytso. |
| 9 | */ |
| 10 | |
| 11 | /* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname |
| 12 | * lookup logic. |
| 13 | */ |
| 14 | /* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture. |
| 15 | */ |
| 16 | |
| 17 | #include <linux/init.h> |
Paul Gortmaker | 630d9c4 | 2011-11-16 23:57:37 -0500 | [diff] [blame] | 18 | #include <linux/export.h> |
David S. Miller | 4469690 | 2012-05-23 20:12:50 -0700 | [diff] [blame] | 19 | #include <linux/kernel.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/slab.h> |
| 21 | #include <linux/fs.h> |
| 22 | #include <linux/namei.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <linux/pagemap.h> |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 24 | #include <linux/fsnotify.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/personality.h> |
| 26 | #include <linux/security.h> |
Mimi Zohar | 6146f0d | 2009-02-04 09:06:57 -0500 | [diff] [blame] | 27 | #include <linux/ima.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | #include <linux/syscalls.h> |
| 29 | #include <linux/mount.h> |
| 30 | #include <linux/audit.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 31 | #include <linux/capability.h> |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 32 | #include <linux/file.h> |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 33 | #include <linux/fcntl.h> |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 34 | #include <linux/device_cgroup.h> |
Al Viro | 5ad4e53 | 2009-03-29 19:50:06 -0400 | [diff] [blame] | 35 | #include <linux/fs_struct.h> |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 36 | #include <linux/posix_acl.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | #include <asm/uaccess.h> |
| 38 | |
Eric Paris | e81e3f4 | 2009-12-04 15:47:36 -0500 | [diff] [blame] | 39 | #include "internal.h" |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 40 | #include "mount.h" |
Eric Paris | e81e3f4 | 2009-12-04 15:47:36 -0500 | [diff] [blame] | 41 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | /* [Feb-1997 T. Schoebel-Theuer] |
| 43 | * Fundamental changes in the pathname lookup mechanisms (namei) |
| 44 | * were necessary because of omirr. The reason is that omirr needs |
| 45 | * to know the _real_ pathname, not the user-supplied one, in case |
| 46 | * of symlinks (and also when transname replacements occur). |
| 47 | * |
| 48 | * The new code replaces the old recursive symlink resolution with |
| 49 | * an iterative one (in case of non-nested symlink chains). It does |
| 50 | * this with calls to <fs>_follow_link(). |
| 51 | * As a side effect, dir_namei(), _namei() and follow_link() are now |
| 52 | * replaced with a single function lookup_dentry() that can handle all |
| 53 | * the special cases of the former code. |
| 54 | * |
| 55 | * With the new dcache, the pathname is stored at each inode, at least as |
| 56 | * long as the refcount of the inode is positive. As a side effect, the |
| 57 | * size of the dcache depends on the inode cache and thus is dynamic. |
| 58 | * |
| 59 | * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink |
| 60 | * resolution to correspond with current state of the code. |
| 61 | * |
| 62 | * Note that the symlink resolution is not *completely* iterative. |
| 63 | * There is still a significant amount of tail- and mid- recursion in |
| 64 | * the algorithm. Also, note that <fs>_readlink() is not used in |
| 65 | * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() |
| 66 | * may return different results than <fs>_follow_link(). Many virtual |
| 67 | * filesystems (including /proc) exhibit this behavior. |
| 68 | */ |
| 69 | |
| 70 | /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: |
| 71 | * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL |
| 72 | * and the name already exists in form of a symlink, try to create the new |
| 73 | * name indicated by the symlink. The old code always complained that the |
| 74 | * name already exists, due to not following the symlink even if its target |
| 75 | * is nonexistent. The new semantics affects also mknod() and link() when |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 76 | * the name is a symlink pointing to a non-existent name. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | * |
| 78 | * I don't know which semantics is the right one, since I have no access |
| 79 | * to standards. But I found by trial that HP-UX 9.0 has the full "new" |
| 80 | * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the |
| 81 | * "old" one. Personally, I think the new semantics is much more logical. |
| 82 | * Note that "ln old new" where "new" is a symlink pointing to a non-existing |
| 83 | * file does succeed in both HP-UX and SunOs, but not in Solaris |
| 84 | * and in the old Linux semantics. |
| 85 | */ |
| 86 | |
| 87 | /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink |
| 88 | * semantics. See the comments in "open_namei" and "do_link" below. |
| 89 | * |
| 90 | * [10-Sep-98 Alan Modra] Another symlink change. |
| 91 | */ |
| 92 | |
| 93 | /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: |
| 94 | * inside the path - always follow. |
| 95 | * in the last component in creation/removal/renaming - never follow. |
| 96 | * if LOOKUP_FOLLOW passed - follow. |
| 97 | * if the pathname has trailing slashes - follow. |
| 98 | * otherwise - don't follow. |
| 99 | * (applied in that order). |
| 100 | * |
| 101 | * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT |
| 102 | * restored for 2.4. This is the last surviving part of old 4.2BSD bug. |
| 103 | * During the 2.4 we need to fix the userland stuff depending on it - |
| 104 | * hopefully we will be able to get rid of that wart in 2.5. So far only |
| 105 | * XEmacs seems to be relying on it... |
| 106 | */ |
| 107 | /* |
| 108 | * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland) |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 109 | * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | * any extra contention... |
| 111 | */ |
| 112 | |
| 113 | /* In order to reduce some races, while at the same time doing additional |
| 114 | * checking and hopefully speeding things up, we copy filenames to the |
| 115 | * kernel data space before using them.. |
| 116 | * |
| 117 | * POSIX.1 2.4: an empty pathname is invalid (ENOENT). |
| 118 | * PATH_MAX includes the nul terminator --RR. |
| 119 | */ |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 120 | static char *getname_flags(const char __user *filename, int flags, int *empty) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | { |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 122 | char *result = __getname(), *err; |
| 123 | int len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 125 | if (unlikely(!result)) |
Eric Paris | 4043cde | 2012-01-03 14:23:08 -0500 | [diff] [blame] | 126 | return ERR_PTR(-ENOMEM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 128 | len = strncpy_from_user(result, filename, PATH_MAX); |
| 129 | err = ERR_PTR(len); |
| 130 | if (unlikely(len < 0)) |
| 131 | goto error; |
| 132 | |
| 133 | /* The empty path is special. */ |
| 134 | if (unlikely(!len)) { |
| 135 | if (empty) |
Eric Paris | 4043cde | 2012-01-03 14:23:08 -0500 | [diff] [blame] | 136 | *empty = 1; |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 137 | err = ERR_PTR(-ENOENT); |
| 138 | if (!(flags & LOOKUP_EMPTY)) |
| 139 | goto error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | } |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 141 | |
| 142 | err = ERR_PTR(-ENAMETOOLONG); |
| 143 | if (likely(len < PATH_MAX)) { |
| 144 | audit_getname(result); |
| 145 | return result; |
| 146 | } |
| 147 | |
| 148 | error: |
| 149 | __putname(result); |
| 150 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | } |
| 152 | |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 153 | char *getname(const char __user * filename) |
| 154 | { |
Linus Torvalds | f7493e5 | 2012-03-22 16:10:40 -0700 | [diff] [blame] | 155 | return getname_flags(filename, 0, NULL); |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 156 | } |
| 157 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | #ifdef CONFIG_AUDITSYSCALL |
| 159 | void putname(const char *name) |
| 160 | { |
Al Viro | 5ac3a9c | 2006-07-16 06:38:45 -0400 | [diff] [blame] | 161 | if (unlikely(!audit_dummy_context())) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | audit_putname(name); |
| 163 | else |
| 164 | __putname(name); |
| 165 | } |
| 166 | EXPORT_SYMBOL(putname); |
| 167 | #endif |
| 168 | |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 169 | static int check_acl(struct inode *inode, int mask) |
| 170 | { |
Linus Torvalds | 84635d6 | 2011-07-25 22:47:03 -0700 | [diff] [blame] | 171 | #ifdef CONFIG_FS_POSIX_ACL |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 172 | struct posix_acl *acl; |
| 173 | |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 174 | if (mask & MAY_NOT_BLOCK) { |
Al Viro | 3567866 | 2011-08-02 21:32:13 -0400 | [diff] [blame] | 175 | acl = get_cached_acl_rcu(inode, ACL_TYPE_ACCESS); |
| 176 | if (!acl) |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 177 | return -EAGAIN; |
Al Viro | 3567866 | 2011-08-02 21:32:13 -0400 | [diff] [blame] | 178 | /* no ->get_acl() calls in RCU mode... */ |
| 179 | if (acl == ACL_NOT_CACHED) |
| 180 | return -ECHILD; |
Ari Savolainen | 206b1d0 | 2011-08-06 19:43:07 +0300 | [diff] [blame] | 181 | return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK); |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 182 | } |
| 183 | |
| 184 | acl = get_cached_acl(inode, ACL_TYPE_ACCESS); |
| 185 | |
| 186 | /* |
Christoph Hellwig | 4e34e71 | 2011-07-23 17:37:31 +0200 | [diff] [blame] | 187 | * A filesystem can force a ACL callback by just never filling the |
| 188 | * ACL cache. But normally you'd fill the cache either at inode |
| 189 | * instantiation time, or on the first ->get_acl call. |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 190 | * |
Christoph Hellwig | 4e34e71 | 2011-07-23 17:37:31 +0200 | [diff] [blame] | 191 | * If the filesystem doesn't have a get_acl() function at all, we'll |
| 192 | * just create the negative cache entry. |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 193 | */ |
| 194 | if (acl == ACL_NOT_CACHED) { |
Christoph Hellwig | 4e34e71 | 2011-07-23 17:37:31 +0200 | [diff] [blame] | 195 | if (inode->i_op->get_acl) { |
| 196 | acl = inode->i_op->get_acl(inode, ACL_TYPE_ACCESS); |
| 197 | if (IS_ERR(acl)) |
| 198 | return PTR_ERR(acl); |
| 199 | } else { |
| 200 | set_cached_acl(inode, ACL_TYPE_ACCESS, NULL); |
| 201 | return -EAGAIN; |
| 202 | } |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 203 | } |
| 204 | |
| 205 | if (acl) { |
| 206 | int error = posix_acl_permission(inode, acl, mask); |
| 207 | posix_acl_release(acl); |
| 208 | return error; |
| 209 | } |
Linus Torvalds | 84635d6 | 2011-07-25 22:47:03 -0700 | [diff] [blame] | 210 | #endif |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 211 | |
| 212 | return -EAGAIN; |
| 213 | } |
| 214 | |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 215 | /* |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 216 | * This does the basic permission checking |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 217 | */ |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 218 | static int acl_permission_check(struct inode *inode, int mask) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 219 | { |
Linus Torvalds | 26cf46b | 2011-05-13 11:51:01 -0700 | [diff] [blame] | 220 | unsigned int mode = inode->i_mode; |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 221 | |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 222 | if (likely(uid_eq(current_fsuid(), inode->i_uid))) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 223 | mode >>= 6; |
| 224 | else { |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 225 | if (IS_POSIXACL(inode) && (mode & S_IRWXG)) { |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 226 | int error = check_acl(inode, mask); |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 227 | if (error != -EAGAIN) |
| 228 | return error; |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 229 | } |
| 230 | |
| 231 | if (in_group_p(inode->i_gid)) |
| 232 | mode >>= 3; |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * If the DACs are ok we don't need any capability check. |
| 237 | */ |
Al Viro | 9c2c703 | 2011-06-20 19:06:22 -0400 | [diff] [blame] | 238 | if ((mask & ~mode & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 239 | return 0; |
| 240 | return -EACCES; |
| 241 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | |
| 243 | /** |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 244 | * generic_permission - check for access rights on a Posix-like filesystem |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | * @inode: inode to check access rights for |
Andreas Gruenbacher | 8fd90c8 | 2011-10-23 23:13:30 +0530 | [diff] [blame] | 246 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC, ...) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 247 | * |
| 248 | * Used to check for read/write/execute permissions on a file. |
| 249 | * We use "fsuid" for this, letting us set arbitrary permissions |
| 250 | * for filesystem access without changing the "normal" uids which |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 251 | * are used for other things. |
| 252 | * |
| 253 | * generic_permission is rcu-walk aware. It returns -ECHILD in case an rcu-walk |
| 254 | * request cannot be satisfied (eg. requires blocking or too much complexity). |
| 255 | * It would then be called again in ref-walk mode. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | */ |
Al Viro | 2830ba7 | 2011-06-20 19:16:29 -0400 | [diff] [blame] | 257 | int generic_permission(struct inode *inode, int mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | { |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 259 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 260 | |
| 261 | /* |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 262 | * Do the basic permission checks. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | */ |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 264 | ret = acl_permission_check(inode, mask); |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 265 | if (ret != -EACCES) |
| 266 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 268 | if (S_ISDIR(inode->i_mode)) { |
| 269 | /* DACs are overridable for directories */ |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 270 | if (inode_capable(inode, CAP_DAC_OVERRIDE)) |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 271 | return 0; |
| 272 | if (!(mask & MAY_WRITE)) |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 273 | if (inode_capable(inode, CAP_DAC_READ_SEARCH)) |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 274 | return 0; |
| 275 | return -EACCES; |
| 276 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | /* |
| 278 | * Read/write DACs are always overridable. |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 279 | * Executable DACs are overridable when there is |
| 280 | * at least one exec bit set. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | */ |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 282 | if (!(mask & MAY_EXEC) || (inode->i_mode & S_IXUGO)) |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 283 | if (inode_capable(inode, CAP_DAC_OVERRIDE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 284 | return 0; |
| 285 | |
| 286 | /* |
| 287 | * Searching includes executable on directories, else just read. |
| 288 | */ |
Serge E. Hallyn | 7ea6600 | 2009-12-29 14:50:19 -0600 | [diff] [blame] | 289 | mask &= MAY_READ | MAY_WRITE | MAY_EXEC; |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 290 | if (mask == MAY_READ) |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 291 | if (inode_capable(inode, CAP_DAC_READ_SEARCH)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 292 | return 0; |
| 293 | |
| 294 | return -EACCES; |
| 295 | } |
| 296 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 297 | /* |
| 298 | * We _really_ want to just do "generic_permission()" without |
| 299 | * even looking at the inode->i_op values. So we keep a cache |
| 300 | * flag in inode->i_opflags, that says "this has not special |
| 301 | * permission function, use the fast case". |
| 302 | */ |
| 303 | static inline int do_inode_permission(struct inode *inode, int mask) |
| 304 | { |
| 305 | if (unlikely(!(inode->i_opflags & IOP_FASTPERM))) { |
| 306 | if (likely(inode->i_op->permission)) |
| 307 | return inode->i_op->permission(inode, mask); |
| 308 | |
| 309 | /* This gets set once for the inode lifetime */ |
| 310 | spin_lock(&inode->i_lock); |
| 311 | inode->i_opflags |= IOP_FASTPERM; |
| 312 | spin_unlock(&inode->i_lock); |
| 313 | } |
| 314 | return generic_permission(inode, mask); |
| 315 | } |
| 316 | |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 317 | /** |
| 318 | * inode_permission - check for access rights to a given inode |
| 319 | * @inode: inode to check permission on |
Andreas Gruenbacher | 8fd90c8 | 2011-10-23 23:13:30 +0530 | [diff] [blame] | 320 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC, ...) |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 321 | * |
| 322 | * Used to check for read/write/execute permissions on an inode. |
| 323 | * We use "fsuid" for this, letting us set arbitrary permissions |
| 324 | * for filesystem access without changing the "normal" uids which |
| 325 | * are used for other things. |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 326 | * |
| 327 | * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask. |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 328 | */ |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 329 | int inode_permission(struct inode *inode, int mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 330 | { |
Al Viro | e6305c4 | 2008-07-15 21:03:57 -0400 | [diff] [blame] | 331 | int retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 332 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 333 | if (unlikely(mask & MAY_WRITE)) { |
Miklos Szeredi | 22590e4 | 2007-10-16 23:27:08 -0700 | [diff] [blame] | 334 | umode_t mode = inode->i_mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | |
| 336 | /* |
| 337 | * Nobody gets write access to a read-only fs. |
| 338 | */ |
| 339 | if (IS_RDONLY(inode) && |
| 340 | (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) |
| 341 | return -EROFS; |
| 342 | |
| 343 | /* |
| 344 | * Nobody gets write access to an immutable file. |
| 345 | */ |
| 346 | if (IS_IMMUTABLE(inode)) |
| 347 | return -EACCES; |
| 348 | } |
| 349 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 350 | retval = do_inode_permission(inode, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | if (retval) |
| 352 | return retval; |
| 353 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 354 | retval = devcgroup_inode_permission(inode, mask); |
| 355 | if (retval) |
| 356 | return retval; |
| 357 | |
Eric Paris | d09ca73 | 2010-07-23 11:43:57 -0400 | [diff] [blame] | 358 | return security_inode_permission(inode, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | } |
| 360 | |
Al Viro | f4d6ff8 | 2011-06-19 13:14:21 -0400 | [diff] [blame] | 361 | /** |
Jan Blunck | 5dd784d0 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 362 | * path_get - get a reference to a path |
| 363 | * @path: path to get the reference to |
| 364 | * |
| 365 | * Given a path increment the reference count to the dentry and the vfsmount. |
| 366 | */ |
| 367 | void path_get(struct path *path) |
| 368 | { |
| 369 | mntget(path->mnt); |
| 370 | dget(path->dentry); |
| 371 | } |
| 372 | EXPORT_SYMBOL(path_get); |
| 373 | |
| 374 | /** |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 375 | * path_put - put a reference to a path |
| 376 | * @path: path to put the reference to |
| 377 | * |
| 378 | * Given a path decrement the reference count to the dentry and the vfsmount. |
| 379 | */ |
| 380 | void path_put(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | { |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 382 | dput(path->dentry); |
| 383 | mntput(path->mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | } |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 385 | EXPORT_SYMBOL(path_put); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 387 | /* |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 388 | * Path walking has 2 modes, rcu-walk and ref-walk (see |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 389 | * Documentation/filesystems/path-lookup.txt). In situations when we can't |
| 390 | * continue in RCU mode, we attempt to drop out of rcu-walk mode and grab |
| 391 | * normal reference counts on dentries and vfsmounts to transition to rcu-walk |
| 392 | * mode. Refcounts are grabbed at the last known good point before rcu-walk |
| 393 | * got stuck, so ref-walk may continue from there. If this is not successful |
| 394 | * (eg. a seqcount has changed), then failure is returned and it's up to caller |
| 395 | * to restart the path walk from the beginning in ref-walk mode. |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 396 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 397 | |
| 398 | /** |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 399 | * unlazy_walk - try to switch to ref-walk mode. |
| 400 | * @nd: nameidata pathwalk data |
| 401 | * @dentry: child of nd->path.dentry or NULL |
Randy Dunlap | 3919162 | 2011-01-08 19:36:21 -0800 | [diff] [blame] | 402 | * Returns: 0 on success, -ECHILD on failure |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 403 | * |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 404 | * unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry |
| 405 | * for ref-walk mode. @dentry must be a path found by a do_lookup call on |
| 406 | * @nd or NULL. Must be called from rcu-walk context. |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 407 | */ |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 408 | static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 409 | { |
| 410 | struct fs_struct *fs = current->fs; |
| 411 | struct dentry *parent = nd->path.dentry; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 412 | int want_root = 0; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 413 | |
| 414 | BUG_ON(!(nd->flags & LOOKUP_RCU)); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 415 | if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) { |
| 416 | want_root = 1; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 417 | spin_lock(&fs->lock); |
| 418 | if (nd->root.mnt != fs->root.mnt || |
| 419 | nd->root.dentry != fs->root.dentry) |
| 420 | goto err_root; |
| 421 | } |
| 422 | spin_lock(&parent->d_lock); |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 423 | if (!dentry) { |
| 424 | if (!__d_rcu_to_refcount(parent, nd->seq)) |
| 425 | goto err_parent; |
| 426 | BUG_ON(nd->inode != parent->d_inode); |
| 427 | } else { |
Al Viro | 94c0d4e | 2011-07-12 21:40:23 -0400 | [diff] [blame] | 428 | if (dentry->d_parent != parent) |
| 429 | goto err_parent; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 430 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
| 431 | if (!__d_rcu_to_refcount(dentry, nd->seq)) |
| 432 | goto err_child; |
| 433 | /* |
| 434 | * If the sequence check on the child dentry passed, then |
| 435 | * the child has not been removed from its parent. This |
| 436 | * means the parent dentry must be valid and able to take |
| 437 | * a reference at this point. |
| 438 | */ |
| 439 | BUG_ON(!IS_ROOT(dentry) && dentry->d_parent != parent); |
| 440 | BUG_ON(!parent->d_count); |
| 441 | parent->d_count++; |
| 442 | spin_unlock(&dentry->d_lock); |
| 443 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 444 | spin_unlock(&parent->d_lock); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 445 | if (want_root) { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 446 | path_get(&nd->root); |
| 447 | spin_unlock(&fs->lock); |
| 448 | } |
| 449 | mntget(nd->path.mnt); |
| 450 | |
| 451 | rcu_read_unlock(); |
| 452 | br_read_unlock(vfsmount_lock); |
| 453 | nd->flags &= ~LOOKUP_RCU; |
| 454 | return 0; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 455 | |
| 456 | err_child: |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 457 | spin_unlock(&dentry->d_lock); |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 458 | err_parent: |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 459 | spin_unlock(&parent->d_lock); |
| 460 | err_root: |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 461 | if (want_root) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 462 | spin_unlock(&fs->lock); |
| 463 | return -ECHILD; |
| 464 | } |
| 465 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 466 | /** |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 467 | * release_open_intent - free up open intent resources |
| 468 | * @nd: pointer to nameidata |
| 469 | */ |
| 470 | void release_open_intent(struct nameidata *nd) |
| 471 | { |
Linus Torvalds | 2dab597 | 2011-02-11 15:53:38 -0800 | [diff] [blame] | 472 | struct file *file = nd->intent.open.file; |
| 473 | |
| 474 | if (file && !IS_ERR(file)) { |
| 475 | if (file->f_path.dentry == NULL) |
| 476 | put_filp(file); |
| 477 | else |
| 478 | fput(file); |
| 479 | } |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 480 | } |
| 481 | |
Al Viro | f60aef7 | 2011-02-15 01:35:28 -0500 | [diff] [blame] | 482 | static inline int d_revalidate(struct dentry *dentry, struct nameidata *nd) |
Nick Piggin | 34286d6 | 2011-01-07 17:49:57 +1100 | [diff] [blame] | 483 | { |
Al Viro | f60aef7 | 2011-02-15 01:35:28 -0500 | [diff] [blame] | 484 | return dentry->d_op->d_revalidate(dentry, nd); |
Nick Piggin | 34286d6 | 2011-01-07 17:49:57 +1100 | [diff] [blame] | 485 | } |
| 486 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 487 | /** |
| 488 | * complete_walk - successful completion of path walk |
| 489 | * @nd: pointer nameidata |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 490 | * |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 491 | * If we had been in RCU mode, drop out of it and legitimize nd->path. |
| 492 | * Revalidate the final result, unless we'd already done that during |
| 493 | * the path walk or the filesystem doesn't ask for it. Return 0 on |
| 494 | * success, -error on failure. In case of failure caller does not |
| 495 | * need to drop nd->path. |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 496 | */ |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 497 | static int complete_walk(struct nameidata *nd) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 498 | { |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 499 | struct dentry *dentry = nd->path.dentry; |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 500 | int status; |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 501 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 502 | if (nd->flags & LOOKUP_RCU) { |
| 503 | nd->flags &= ~LOOKUP_RCU; |
| 504 | if (!(nd->flags & LOOKUP_ROOT)) |
| 505 | nd->root.mnt = NULL; |
| 506 | spin_lock(&dentry->d_lock); |
| 507 | if (unlikely(!__d_rcu_to_refcount(dentry, nd->seq))) { |
| 508 | spin_unlock(&dentry->d_lock); |
| 509 | rcu_read_unlock(); |
| 510 | br_read_unlock(vfsmount_lock); |
| 511 | return -ECHILD; |
| 512 | } |
| 513 | BUG_ON(nd->inode != dentry->d_inode); |
| 514 | spin_unlock(&dentry->d_lock); |
| 515 | mntget(nd->path.mnt); |
| 516 | rcu_read_unlock(); |
| 517 | br_read_unlock(vfsmount_lock); |
| 518 | } |
| 519 | |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 520 | if (likely(!(nd->flags & LOOKUP_JUMPED))) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 521 | return 0; |
| 522 | |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 523 | if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE))) |
| 524 | return 0; |
| 525 | |
| 526 | if (likely(!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT))) |
| 527 | return 0; |
| 528 | |
| 529 | /* Note: we do not d_invalidate() */ |
Nick Piggin | 34286d6 | 2011-01-07 17:49:57 +1100 | [diff] [blame] | 530 | status = d_revalidate(dentry, nd); |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 531 | if (status > 0) |
| 532 | return 0; |
| 533 | |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 534 | if (!status) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 535 | status = -ESTALE; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 536 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 537 | path_put(&nd->path); |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 538 | return status; |
| 539 | } |
| 540 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 541 | static __always_inline void set_root(struct nameidata *nd) |
| 542 | { |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 543 | if (!nd->root.mnt) |
| 544 | get_fs_root(current->fs, &nd->root); |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 545 | } |
| 546 | |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 547 | static int link_path_walk(const char *, struct nameidata *); |
| 548 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 549 | static __always_inline void set_root_rcu(struct nameidata *nd) |
| 550 | { |
| 551 | if (!nd->root.mnt) { |
| 552 | struct fs_struct *fs = current->fs; |
Nick Piggin | c28cc36 | 2011-01-07 17:49:53 +1100 | [diff] [blame] | 553 | unsigned seq; |
| 554 | |
| 555 | do { |
| 556 | seq = read_seqcount_begin(&fs->seq); |
| 557 | nd->root = fs->root; |
Tim Chen | c153001 | 2011-04-15 11:39:29 -0700 | [diff] [blame] | 558 | nd->seq = __read_seqcount_begin(&nd->root.dentry->d_seq); |
Nick Piggin | c28cc36 | 2011-01-07 17:49:53 +1100 | [diff] [blame] | 559 | } while (read_seqcount_retry(&fs->seq, seq)); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 560 | } |
| 561 | } |
| 562 | |
Arjan van de Ven | f166235 | 2006-01-14 13:21:31 -0800 | [diff] [blame] | 563 | static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 565 | int ret; |
| 566 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | if (IS_ERR(link)) |
| 568 | goto fail; |
| 569 | |
| 570 | if (*link == '/') { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 571 | set_root(nd); |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 572 | path_put(&nd->path); |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 573 | nd->path = nd->root; |
| 574 | path_get(&nd->root); |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 575 | nd->flags |= LOOKUP_JUMPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 576 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 577 | nd->inode = nd->path.dentry->d_inode; |
Christoph Hellwig | b4091d5 | 2008-11-05 15:07:21 +0100 | [diff] [blame] | 578 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 579 | ret = link_path_walk(link, nd); |
| 580 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 581 | fail: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 582 | path_put(&nd->path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 583 | return PTR_ERR(link); |
| 584 | } |
| 585 | |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 586 | static void path_put_conditional(struct path *path, struct nameidata *nd) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 587 | { |
| 588 | dput(path->dentry); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 589 | if (path->mnt != nd->path.mnt) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 590 | mntput(path->mnt); |
| 591 | } |
| 592 | |
Nick Piggin | 7b9337a | 2011-01-14 08:42:43 +0000 | [diff] [blame] | 593 | static inline void path_to_nameidata(const struct path *path, |
| 594 | struct nameidata *nd) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 595 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 596 | if (!(nd->flags & LOOKUP_RCU)) { |
| 597 | dput(nd->path.dentry); |
| 598 | if (nd->path.mnt != path->mnt) |
| 599 | mntput(nd->path.mnt); |
Huang Shijie | 9a22968 | 2010-04-02 17:37:13 +0800 | [diff] [blame] | 600 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 601 | nd->path.mnt = path->mnt; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 602 | nd->path.dentry = path->dentry; |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 603 | } |
| 604 | |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 605 | static inline void put_link(struct nameidata *nd, struct path *link, void *cookie) |
| 606 | { |
| 607 | struct inode *inode = link->dentry->d_inode; |
| 608 | if (!IS_ERR(cookie) && inode->i_op->put_link) |
| 609 | inode->i_op->put_link(link->dentry, nd, cookie); |
| 610 | path_put(link); |
| 611 | } |
| 612 | |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 613 | static __always_inline int |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 614 | follow_link(struct path *link, struct nameidata *nd, void **p) |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 615 | { |
| 616 | int error; |
Nick Piggin | 7b9337a | 2011-01-14 08:42:43 +0000 | [diff] [blame] | 617 | struct dentry *dentry = link->dentry; |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 618 | |
Al Viro | 844a391 | 2011-02-15 00:38:26 -0500 | [diff] [blame] | 619 | BUG_ON(nd->flags & LOOKUP_RCU); |
| 620 | |
Al Viro | 0e79458 | 2011-03-16 02:45:02 -0400 | [diff] [blame] | 621 | if (link->mnt == nd->path.mnt) |
| 622 | mntget(link->mnt); |
| 623 | |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 624 | if (unlikely(current->total_link_count >= 40)) { |
| 625 | *p = ERR_PTR(-ELOOP); /* no ->put_link(), please */ |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 626 | path_put(&nd->path); |
| 627 | return -ELOOP; |
| 628 | } |
| 629 | cond_resched(); |
| 630 | current->total_link_count++; |
| 631 | |
Al Viro | 68ac123 | 2012-03-15 08:21:57 -0400 | [diff] [blame] | 632 | touch_atime(link); |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 633 | nd_set_link(nd, NULL); |
| 634 | |
Al Viro | 36f3b4f | 2011-02-22 21:24:38 -0500 | [diff] [blame] | 635 | error = security_inode_follow_link(link->dentry, nd); |
| 636 | if (error) { |
| 637 | *p = ERR_PTR(error); /* no ->put_link(), please */ |
| 638 | path_put(&nd->path); |
| 639 | return error; |
| 640 | } |
| 641 | |
Al Viro | 86acdca1 | 2009-12-22 23:45:11 -0500 | [diff] [blame] | 642 | nd->last_type = LAST_BIND; |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 643 | *p = dentry->d_inode->i_op->follow_link(dentry, nd); |
| 644 | error = PTR_ERR(*p); |
| 645 | if (!IS_ERR(*p)) { |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 646 | char *s = nd_get_link(nd); |
| 647 | error = 0; |
| 648 | if (s) |
| 649 | error = __vfs_follow_link(nd, s); |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 650 | else if (nd->last_type == LAST_BIND) { |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 651 | nd->flags |= LOOKUP_JUMPED; |
Al Viro | b21041d | 2011-03-14 20:01:51 -0400 | [diff] [blame] | 652 | nd->inode = nd->path.dentry->d_inode; |
| 653 | if (nd->inode->i_op->follow_link) { |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 654 | /* stepped on a _really_ weird one */ |
| 655 | path_put(&nd->path); |
| 656 | error = -ELOOP; |
| 657 | } |
| 658 | } |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 659 | } |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 660 | return error; |
| 661 | } |
| 662 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 663 | static int follow_up_rcu(struct path *path) |
| 664 | { |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 665 | struct mount *mnt = real_mount(path->mnt); |
| 666 | struct mount *parent; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 667 | struct dentry *mountpoint; |
| 668 | |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 669 | parent = mnt->mnt_parent; |
| 670 | if (&parent->mnt == path->mnt) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 671 | return 0; |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 672 | mountpoint = mnt->mnt_mountpoint; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 673 | path->dentry = mountpoint; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 674 | path->mnt = &parent->mnt; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 675 | return 1; |
| 676 | } |
| 677 | |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 678 | int follow_up(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 679 | { |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 680 | struct mount *mnt = real_mount(path->mnt); |
| 681 | struct mount *parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 682 | struct dentry *mountpoint; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 683 | |
| 684 | br_read_lock(vfsmount_lock); |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 685 | parent = mnt->mnt_parent; |
| 686 | if (&parent->mnt == path->mnt) { |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 687 | br_read_unlock(vfsmount_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | return 0; |
| 689 | } |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 690 | mntget(&parent->mnt); |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 691 | mountpoint = dget(mnt->mnt_mountpoint); |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 692 | br_read_unlock(vfsmount_lock); |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 693 | dput(path->dentry); |
| 694 | path->dentry = mountpoint; |
| 695 | mntput(path->mnt); |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 696 | path->mnt = &parent->mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 697 | return 1; |
| 698 | } |
| 699 | |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 700 | /* |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 701 | * Perform an automount |
| 702 | * - return -EISDIR to tell follow_managed() to stop and return the path we |
| 703 | * were called with. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 704 | */ |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 705 | static int follow_automount(struct path *path, unsigned flags, |
| 706 | bool *need_mntput) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 707 | { |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 708 | struct vfsmount *mnt; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 709 | int err; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 710 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 711 | if (!path->dentry->d_op || !path->dentry->d_op->d_automount) |
| 712 | return -EREMOTE; |
Al Viro | 463ffb2 | 2005-06-06 13:36:05 -0700 | [diff] [blame] | 713 | |
Miklos Szeredi | 0ec26fd | 2011-09-05 18:06:26 +0200 | [diff] [blame] | 714 | /* We don't want to mount if someone's just doing a stat - |
| 715 | * unless they're stat'ing a directory and appended a '/' to |
| 716 | * the name. |
| 717 | * |
| 718 | * We do, however, want to mount if someone wants to open or |
| 719 | * create a file of any type under the mountpoint, wants to |
| 720 | * traverse through the mountpoint or wants to open the |
| 721 | * mounted directory. Also, autofs may mark negative dentries |
| 722 | * as being automount points. These will need the attentions |
| 723 | * of the daemon to instantiate them before they can be used. |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 724 | */ |
Miklos Szeredi | 0ec26fd | 2011-09-05 18:06:26 +0200 | [diff] [blame] | 725 | if (!(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY | |
Linus Torvalds | d94c177 | 2011-09-26 17:44:55 -0700 | [diff] [blame] | 726 | LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) && |
Miklos Szeredi | 0ec26fd | 2011-09-05 18:06:26 +0200 | [diff] [blame] | 727 | path->dentry->d_inode) |
| 728 | return -EISDIR; |
| 729 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 730 | current->total_link_count++; |
| 731 | if (current->total_link_count >= 40) |
| 732 | return -ELOOP; |
| 733 | |
| 734 | mnt = path->dentry->d_op->d_automount(path); |
| 735 | if (IS_ERR(mnt)) { |
| 736 | /* |
| 737 | * The filesystem is allowed to return -EISDIR here to indicate |
| 738 | * it doesn't want to automount. For instance, autofs would do |
| 739 | * this so that its userspace daemon can mount on this dentry. |
| 740 | * |
| 741 | * However, we can only permit this if it's a terminal point in |
| 742 | * the path being looked up; if it wasn't then the remainder of |
| 743 | * the path is inaccessible and we should say so. |
| 744 | */ |
Al Viro | 49084c3 | 2011-06-25 21:59:52 -0400 | [diff] [blame] | 745 | if (PTR_ERR(mnt) == -EISDIR && (flags & LOOKUP_PARENT)) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 746 | return -EREMOTE; |
| 747 | return PTR_ERR(mnt); |
| 748 | } |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 749 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 750 | if (!mnt) /* mount collision */ |
| 751 | return 0; |
| 752 | |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 753 | if (!*need_mntput) { |
| 754 | /* lock_mount() may release path->mnt on error */ |
| 755 | mntget(path->mnt); |
| 756 | *need_mntput = true; |
| 757 | } |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 758 | err = finish_automount(mnt, path); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 759 | |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 760 | switch (err) { |
| 761 | case -EBUSY: |
| 762 | /* Someone else made a mount here whilst we were busy */ |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 763 | return 0; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 764 | case 0: |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 765 | path_put(path); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 766 | path->mnt = mnt; |
| 767 | path->dentry = dget(mnt->mnt_root); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 768 | return 0; |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 769 | default: |
| 770 | return err; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 771 | } |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 772 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 773 | } |
| 774 | |
| 775 | /* |
| 776 | * Handle a dentry that is managed in some way. |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 777 | * - Flagged for transit management (autofs) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 778 | * - Flagged as mountpoint |
| 779 | * - Flagged as automount point |
| 780 | * |
| 781 | * This may only be called in refwalk mode. |
| 782 | * |
| 783 | * Serialization is taken care of in namespace.c |
| 784 | */ |
| 785 | static int follow_managed(struct path *path, unsigned flags) |
| 786 | { |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 787 | struct vfsmount *mnt = path->mnt; /* held by caller, must be left alone */ |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 788 | unsigned managed; |
| 789 | bool need_mntput = false; |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 790 | int ret = 0; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 791 | |
| 792 | /* Given that we're not holding a lock here, we retain the value in a |
| 793 | * local variable for each dentry as we look at it so that we don't see |
| 794 | * the components of that value change under us */ |
| 795 | while (managed = ACCESS_ONCE(path->dentry->d_flags), |
| 796 | managed &= DCACHE_MANAGED_DENTRY, |
| 797 | unlikely(managed != 0)) { |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 798 | /* Allow the filesystem to manage the transit without i_mutex |
| 799 | * being held. */ |
| 800 | if (managed & DCACHE_MANAGE_TRANSIT) { |
| 801 | BUG_ON(!path->dentry->d_op); |
| 802 | BUG_ON(!path->dentry->d_op->d_manage); |
Al Viro | 1aed3e4 | 2011-03-18 09:09:02 -0400 | [diff] [blame] | 803 | ret = path->dentry->d_op->d_manage(path->dentry, false); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 804 | if (ret < 0) |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 805 | break; |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 806 | } |
| 807 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 808 | /* Transit to a mounted filesystem. */ |
| 809 | if (managed & DCACHE_MOUNTED) { |
| 810 | struct vfsmount *mounted = lookup_mnt(path); |
| 811 | if (mounted) { |
| 812 | dput(path->dentry); |
| 813 | if (need_mntput) |
| 814 | mntput(path->mnt); |
| 815 | path->mnt = mounted; |
| 816 | path->dentry = dget(mounted->mnt_root); |
| 817 | need_mntput = true; |
| 818 | continue; |
| 819 | } |
| 820 | |
| 821 | /* Something is mounted on this dentry in another |
| 822 | * namespace and/or whatever was mounted there in this |
| 823 | * namespace got unmounted before we managed to get the |
| 824 | * vfsmount_lock */ |
| 825 | } |
| 826 | |
| 827 | /* Handle an automount point */ |
| 828 | if (managed & DCACHE_NEED_AUTOMOUNT) { |
| 829 | ret = follow_automount(path, flags, &need_mntput); |
| 830 | if (ret < 0) |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 831 | break; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 832 | continue; |
| 833 | } |
| 834 | |
| 835 | /* We didn't change the current path point */ |
| 836 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 837 | } |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 838 | |
| 839 | if (need_mntput && path->mnt == mnt) |
| 840 | mntput(path->mnt); |
| 841 | if (ret == -EISDIR) |
| 842 | ret = 0; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 843 | return ret < 0 ? ret : need_mntput; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 844 | } |
| 845 | |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 846 | int follow_down_one(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 847 | { |
| 848 | struct vfsmount *mounted; |
| 849 | |
Al Viro | 1c755af | 2009-04-18 14:06:57 -0400 | [diff] [blame] | 850 | mounted = lookup_mnt(path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | if (mounted) { |
Al Viro | 9393bd0 | 2009-04-18 13:58:15 -0400 | [diff] [blame] | 852 | dput(path->dentry); |
| 853 | mntput(path->mnt); |
| 854 | path->mnt = mounted; |
| 855 | path->dentry = dget(mounted->mnt_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 856 | return 1; |
| 857 | } |
| 858 | return 0; |
| 859 | } |
| 860 | |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 861 | static inline bool managed_dentry_might_block(struct dentry *dentry) |
| 862 | { |
| 863 | return (dentry->d_flags & DCACHE_MANAGE_TRANSIT && |
| 864 | dentry->d_op->d_manage(dentry, true) < 0); |
| 865 | } |
| 866 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 867 | /* |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 868 | * Try to skip to top of mountpoint pile in rcuwalk mode. Fail if |
| 869 | * we meet a managed dentry that would need blocking. |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 870 | */ |
| 871 | static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 872 | struct inode **inode) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 873 | { |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 874 | for (;;) { |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 875 | struct mount *mounted; |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 876 | /* |
| 877 | * Don't forget we might have a non-mountpoint managed dentry |
| 878 | * that wants to block transit. |
| 879 | */ |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 880 | if (unlikely(managed_dentry_might_block(path->dentry))) |
David Howells | ab90911 | 2011-01-14 18:46:51 +0000 | [diff] [blame] | 881 | return false; |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 882 | |
| 883 | if (!d_mountpoint(path->dentry)) |
| 884 | break; |
| 885 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 886 | mounted = __lookup_mnt(path->mnt, path->dentry, 1); |
| 887 | if (!mounted) |
| 888 | break; |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 889 | path->mnt = &mounted->mnt; |
| 890 | path->dentry = mounted->mnt.mnt_root; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 891 | nd->flags |= LOOKUP_JUMPED; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 892 | nd->seq = read_seqcount_begin(&path->dentry->d_seq); |
Linus Torvalds | 5943026 | 2011-07-18 15:43:29 -0700 | [diff] [blame] | 893 | /* |
| 894 | * Update the inode too. We don't need to re-check the |
| 895 | * dentry sequence number here after this d_inode read, |
| 896 | * because a mount-point is always pinned. |
| 897 | */ |
| 898 | *inode = path->dentry->d_inode; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 899 | } |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 900 | return true; |
| 901 | } |
| 902 | |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 903 | static void follow_mount_rcu(struct nameidata *nd) |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 904 | { |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 905 | while (d_mountpoint(nd->path.dentry)) { |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 906 | struct mount *mounted; |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 907 | mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1); |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 908 | if (!mounted) |
| 909 | break; |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 910 | nd->path.mnt = &mounted->mnt; |
| 911 | nd->path.dentry = mounted->mnt.mnt_root; |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 912 | nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 913 | } |
| 914 | } |
| 915 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 916 | static int follow_dotdot_rcu(struct nameidata *nd) |
| 917 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 918 | set_root_rcu(nd); |
| 919 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 920 | while (1) { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 921 | if (nd->path.dentry == nd->root.dentry && |
| 922 | nd->path.mnt == nd->root.mnt) { |
| 923 | break; |
| 924 | } |
| 925 | if (nd->path.dentry != nd->path.mnt->mnt_root) { |
| 926 | struct dentry *old = nd->path.dentry; |
| 927 | struct dentry *parent = old->d_parent; |
| 928 | unsigned seq; |
| 929 | |
| 930 | seq = read_seqcount_begin(&parent->d_seq); |
| 931 | if (read_seqcount_retry(&old->d_seq, nd->seq)) |
Al Viro | ef7562d | 2011-03-04 14:35:59 -0500 | [diff] [blame] | 932 | goto failed; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 933 | nd->path.dentry = parent; |
| 934 | nd->seq = seq; |
| 935 | break; |
| 936 | } |
| 937 | if (!follow_up_rcu(&nd->path)) |
| 938 | break; |
| 939 | nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 940 | } |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 941 | follow_mount_rcu(nd); |
| 942 | nd->inode = nd->path.dentry->d_inode; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 943 | return 0; |
Al Viro | ef7562d | 2011-03-04 14:35:59 -0500 | [diff] [blame] | 944 | |
| 945 | failed: |
| 946 | nd->flags &= ~LOOKUP_RCU; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 947 | if (!(nd->flags & LOOKUP_ROOT)) |
| 948 | nd->root.mnt = NULL; |
Al Viro | ef7562d | 2011-03-04 14:35:59 -0500 | [diff] [blame] | 949 | rcu_read_unlock(); |
| 950 | br_read_unlock(vfsmount_lock); |
| 951 | return -ECHILD; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 952 | } |
| 953 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 954 | /* |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 955 | * Follow down to the covering mount currently visible to userspace. At each |
| 956 | * point, the filesystem owning that dentry may be queried as to whether the |
| 957 | * caller is permitted to proceed or not. |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 958 | */ |
Al Viro | 7cc90cc | 2011-03-18 09:04:20 -0400 | [diff] [blame] | 959 | int follow_down(struct path *path) |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 960 | { |
| 961 | unsigned managed; |
| 962 | int ret; |
| 963 | |
| 964 | while (managed = ACCESS_ONCE(path->dentry->d_flags), |
| 965 | unlikely(managed & DCACHE_MANAGED_DENTRY)) { |
| 966 | /* Allow the filesystem to manage the transit without i_mutex |
| 967 | * being held. |
| 968 | * |
| 969 | * We indicate to the filesystem if someone is trying to mount |
| 970 | * something here. This gives autofs the chance to deny anyone |
| 971 | * other than its daemon the right to mount on its |
| 972 | * superstructure. |
| 973 | * |
| 974 | * The filesystem may sleep at this point. |
| 975 | */ |
| 976 | if (managed & DCACHE_MANAGE_TRANSIT) { |
| 977 | BUG_ON(!path->dentry->d_op); |
| 978 | BUG_ON(!path->dentry->d_op->d_manage); |
David Howells | ab90911 | 2011-01-14 18:46:51 +0000 | [diff] [blame] | 979 | ret = path->dentry->d_op->d_manage( |
Al Viro | 1aed3e4 | 2011-03-18 09:09:02 -0400 | [diff] [blame] | 980 | path->dentry, false); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 981 | if (ret < 0) |
| 982 | return ret == -EISDIR ? 0 : ret; |
| 983 | } |
| 984 | |
| 985 | /* Transit to a mounted filesystem. */ |
| 986 | if (managed & DCACHE_MOUNTED) { |
| 987 | struct vfsmount *mounted = lookup_mnt(path); |
| 988 | if (!mounted) |
| 989 | break; |
| 990 | dput(path->dentry); |
| 991 | mntput(path->mnt); |
| 992 | path->mnt = mounted; |
| 993 | path->dentry = dget(mounted->mnt_root); |
| 994 | continue; |
| 995 | } |
| 996 | |
| 997 | /* Don't handle automount points here */ |
| 998 | break; |
| 999 | } |
| 1000 | return 0; |
| 1001 | } |
| 1002 | |
| 1003 | /* |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1004 | * Skip to top of mountpoint pile in refwalk mode for follow_dotdot() |
| 1005 | */ |
| 1006 | static void follow_mount(struct path *path) |
| 1007 | { |
| 1008 | while (d_mountpoint(path->dentry)) { |
| 1009 | struct vfsmount *mounted = lookup_mnt(path); |
| 1010 | if (!mounted) |
| 1011 | break; |
| 1012 | dput(path->dentry); |
| 1013 | mntput(path->mnt); |
| 1014 | path->mnt = mounted; |
| 1015 | path->dentry = dget(mounted->mnt_root); |
| 1016 | } |
| 1017 | } |
| 1018 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1019 | static void follow_dotdot(struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1020 | { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1021 | set_root(nd); |
Andreas Mohr | e518ddb | 2006-09-29 02:01:22 -0700 | [diff] [blame] | 1022 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1023 | while(1) { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1024 | struct dentry *old = nd->path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1025 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1026 | if (nd->path.dentry == nd->root.dentry && |
| 1027 | nd->path.mnt == nd->root.mnt) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1028 | break; |
| 1029 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1030 | if (nd->path.dentry != nd->path.mnt->mnt_root) { |
Al Viro | 3088dd7 | 2010-01-30 15:47:29 -0500 | [diff] [blame] | 1031 | /* rare case of legitimate dget_parent()... */ |
| 1032 | nd->path.dentry = dget_parent(nd->path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1033 | dput(old); |
| 1034 | break; |
| 1035 | } |
Al Viro | 3088dd7 | 2010-01-30 15:47:29 -0500 | [diff] [blame] | 1036 | if (!follow_up(&nd->path)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1037 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1038 | } |
Al Viro | 79ed022 | 2009-04-18 13:59:41 -0400 | [diff] [blame] | 1039 | follow_mount(&nd->path); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1040 | nd->inode = nd->path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1041 | } |
| 1042 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1043 | /* |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1044 | * This looks up the name in dcache, possibly revalidates the old dentry and |
| 1045 | * allocates a new one if not found or not valid. In the need_lookup argument |
| 1046 | * returns whether i_op->lookup is necessary. |
| 1047 | * |
| 1048 | * dir->d_inode->i_mutex must be held |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1049 | */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1050 | static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir, |
| 1051 | struct nameidata *nd, bool *need_lookup) |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1052 | { |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1053 | struct dentry *dentry; |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1054 | int error; |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1055 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1056 | *need_lookup = false; |
| 1057 | dentry = d_lookup(dir, name); |
| 1058 | if (dentry) { |
| 1059 | if (d_need_lookup(dentry)) { |
| 1060 | *need_lookup = true; |
| 1061 | } else if (dentry->d_flags & DCACHE_OP_REVALIDATE) { |
| 1062 | error = d_revalidate(dentry, nd); |
| 1063 | if (unlikely(error <= 0)) { |
| 1064 | if (error < 0) { |
| 1065 | dput(dentry); |
| 1066 | return ERR_PTR(error); |
| 1067 | } else if (!d_invalidate(dentry)) { |
| 1068 | dput(dentry); |
| 1069 | dentry = NULL; |
| 1070 | } |
| 1071 | } |
| 1072 | } |
| 1073 | } |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1074 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1075 | if (!dentry) { |
| 1076 | dentry = d_alloc(dir, name); |
| 1077 | if (unlikely(!dentry)) |
| 1078 | return ERR_PTR(-ENOMEM); |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1079 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1080 | *need_lookup = true; |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1081 | } |
| 1082 | return dentry; |
| 1083 | } |
| 1084 | |
| 1085 | /* |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1086 | * Call i_op->lookup on the dentry. The dentry must be negative but may be |
| 1087 | * hashed if it was pouplated with DCACHE_NEED_LOOKUP. |
| 1088 | * |
| 1089 | * dir->d_inode->i_mutex must be held |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1090 | */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1091 | static struct dentry *lookup_real(struct inode *dir, struct dentry *dentry, |
| 1092 | struct nameidata *nd) |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1093 | { |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1094 | struct dentry *old; |
| 1095 | |
| 1096 | /* Don't create child dentry for a dead directory. */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1097 | if (unlikely(IS_DEADDIR(dir))) { |
Miklos Szeredi | e188dc0 | 2012-02-03 14:25:18 +0100 | [diff] [blame] | 1098 | dput(dentry); |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1099 | return ERR_PTR(-ENOENT); |
Miklos Szeredi | e188dc0 | 2012-02-03 14:25:18 +0100 | [diff] [blame] | 1100 | } |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1101 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1102 | old = dir->i_op->lookup(dir, dentry, nd); |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1103 | if (unlikely(old)) { |
| 1104 | dput(dentry); |
| 1105 | dentry = old; |
| 1106 | } |
| 1107 | return dentry; |
| 1108 | } |
| 1109 | |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1110 | static struct dentry *__lookup_hash(struct qstr *name, |
| 1111 | struct dentry *base, struct nameidata *nd) |
| 1112 | { |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1113 | bool need_lookup; |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1114 | struct dentry *dentry; |
| 1115 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1116 | dentry = lookup_dcache(name, base, nd, &need_lookup); |
| 1117 | if (!need_lookup) |
| 1118 | return dentry; |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1119 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1120 | return lookup_real(base->d_inode, dentry, nd); |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1121 | } |
| 1122 | |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1123 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1124 | * It's more convoluted than I'd like it to be, but... it's still fairly |
| 1125 | * small and for now I'd prefer to have fast path as straight as possible. |
| 1126 | * It _is_ time-critical. |
| 1127 | */ |
| 1128 | static int do_lookup(struct nameidata *nd, struct qstr *name, |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1129 | struct path *path, struct inode **inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1130 | { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1131 | struct vfsmount *mnt = nd->path.mnt; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1132 | struct dentry *dentry, *parent = nd->path.dentry; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1133 | int need_reval = 1; |
| 1134 | int status = 1; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1135 | int err; |
| 1136 | |
Al Viro | 3cac260 | 2009-08-13 18:27:43 +0400 | [diff] [blame] | 1137 | /* |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1138 | * Rename seqlock is not required here because in the off chance |
| 1139 | * of a false negative due to a concurrent rename, we're going to |
| 1140 | * do the non-racy lookup, below. |
| 1141 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1142 | if (nd->flags & LOOKUP_RCU) { |
| 1143 | unsigned seq; |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1144 | dentry = __d_lookup_rcu(parent, name, &seq, nd->inode); |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1145 | if (!dentry) |
| 1146 | goto unlazy; |
| 1147 | |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1148 | /* |
| 1149 | * This sequence count validates that the inode matches |
| 1150 | * the dentry name information from lookup. |
| 1151 | */ |
| 1152 | *inode = dentry->d_inode; |
| 1153 | if (read_seqcount_retry(&dentry->d_seq, seq)) |
| 1154 | return -ECHILD; |
| 1155 | |
| 1156 | /* |
| 1157 | * This sequence count validates that the parent had no |
| 1158 | * changes while we did the lookup of the dentry above. |
| 1159 | * |
| 1160 | * The memory barrier in read_seqcount_begin of child is |
| 1161 | * enough, we can use __read_seqcount_retry here. |
| 1162 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1163 | if (__read_seqcount_retry(&parent->d_seq, nd->seq)) |
| 1164 | return -ECHILD; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1165 | nd->seq = seq; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1166 | |
Miklos Szeredi | fa4ee15 | 2012-03-26 12:54:19 +0200 | [diff] [blame] | 1167 | if (unlikely(d_need_lookup(dentry))) |
| 1168 | goto unlazy; |
Al Viro | 2464308 | 2011-02-15 01:26:22 -0500 | [diff] [blame] | 1169 | if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) { |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1170 | status = d_revalidate(dentry, nd); |
| 1171 | if (unlikely(status <= 0)) { |
| 1172 | if (status != -ECHILD) |
| 1173 | need_reval = 0; |
| 1174 | goto unlazy; |
| 1175 | } |
Al Viro | 2464308 | 2011-02-15 01:26:22 -0500 | [diff] [blame] | 1176 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1177 | path->mnt = mnt; |
| 1178 | path->dentry = dentry; |
Al Viro | d6e9bd2 | 2011-05-27 07:03:15 -0400 | [diff] [blame] | 1179 | if (unlikely(!__follow_mount_rcu(nd, path, inode))) |
| 1180 | goto unlazy; |
| 1181 | if (unlikely(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT)) |
| 1182 | goto unlazy; |
| 1183 | return 0; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1184 | unlazy: |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 1185 | if (unlazy_walk(nd, dentry)) |
| 1186 | return -ECHILD; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1187 | } else { |
| 1188 | dentry = __d_lookup(parent, name); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1189 | } |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1190 | |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1191 | if (unlikely(!dentry)) |
| 1192 | goto need_lookup; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1193 | |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1194 | if (unlikely(d_need_lookup(dentry))) { |
| 1195 | dput(dentry); |
| 1196 | goto need_lookup; |
Al Viro | 2464308 | 2011-02-15 01:26:22 -0500 | [diff] [blame] | 1197 | } |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1198 | |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1199 | if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval) |
| 1200 | status = d_revalidate(dentry, nd); |
| 1201 | if (unlikely(status <= 0)) { |
| 1202 | if (status < 0) { |
| 1203 | dput(dentry); |
| 1204 | return status; |
| 1205 | } |
| 1206 | if (!d_invalidate(dentry)) { |
| 1207 | dput(dentry); |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1208 | goto need_lookup; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1209 | } |
| 1210 | } |
Al Viro | 3f6c7c7 | 2012-03-30 14:04:16 -0400 | [diff] [blame] | 1211 | done: |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1212 | path->mnt = mnt; |
| 1213 | path->dentry = dentry; |
| 1214 | err = follow_managed(path, nd->flags); |
Ian Kent | 8931221 | 2011-01-18 12:06:10 +0800 | [diff] [blame] | 1215 | if (unlikely(err < 0)) { |
| 1216 | path_put_conditional(path, nd); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1217 | return err; |
Ian Kent | 8931221 | 2011-01-18 12:06:10 +0800 | [diff] [blame] | 1218 | } |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 1219 | if (err) |
| 1220 | nd->flags |= LOOKUP_JUMPED; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1221 | *inode = path->dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1222 | return 0; |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1223 | |
| 1224 | need_lookup: |
| 1225 | BUG_ON(nd->inode != parent->d_inode); |
| 1226 | |
| 1227 | mutex_lock(&parent->d_inode->i_mutex); |
| 1228 | dentry = __lookup_hash(name, parent, nd); |
| 1229 | mutex_unlock(&parent->d_inode->i_mutex); |
| 1230 | if (IS_ERR(dentry)) |
| 1231 | return PTR_ERR(dentry); |
| 1232 | goto done; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | } |
| 1234 | |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1235 | static inline int may_lookup(struct nameidata *nd) |
| 1236 | { |
| 1237 | if (nd->flags & LOOKUP_RCU) { |
Al Viro | 4ad5abb | 2011-06-20 19:57:03 -0400 | [diff] [blame] | 1238 | int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK); |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1239 | if (err != -ECHILD) |
| 1240 | return err; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 1241 | if (unlazy_walk(nd, NULL)) |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1242 | return -ECHILD; |
| 1243 | } |
Al Viro | 4ad5abb | 2011-06-20 19:57:03 -0400 | [diff] [blame] | 1244 | return inode_permission(nd->inode, MAY_EXEC); |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1245 | } |
| 1246 | |
Al Viro | 9856fa1 | 2011-03-04 14:22:06 -0500 | [diff] [blame] | 1247 | static inline int handle_dots(struct nameidata *nd, int type) |
| 1248 | { |
| 1249 | if (type == LAST_DOTDOT) { |
| 1250 | if (nd->flags & LOOKUP_RCU) { |
| 1251 | if (follow_dotdot_rcu(nd)) |
| 1252 | return -ECHILD; |
| 1253 | } else |
| 1254 | follow_dotdot(nd); |
| 1255 | } |
| 1256 | return 0; |
| 1257 | } |
| 1258 | |
Al Viro | 951361f | 2011-03-04 14:44:37 -0500 | [diff] [blame] | 1259 | static void terminate_walk(struct nameidata *nd) |
| 1260 | { |
| 1261 | if (!(nd->flags & LOOKUP_RCU)) { |
| 1262 | path_put(&nd->path); |
| 1263 | } else { |
| 1264 | nd->flags &= ~LOOKUP_RCU; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1265 | if (!(nd->flags & LOOKUP_ROOT)) |
| 1266 | nd->root.mnt = NULL; |
Al Viro | 951361f | 2011-03-04 14:44:37 -0500 | [diff] [blame] | 1267 | rcu_read_unlock(); |
| 1268 | br_read_unlock(vfsmount_lock); |
| 1269 | } |
| 1270 | } |
| 1271 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1272 | /* |
| 1273 | * Do we need to follow links? We _really_ want to be able |
| 1274 | * to do this check without having to look at inode->i_op, |
| 1275 | * so we keep a cache of "no, this doesn't need follow_link" |
| 1276 | * for the common case. |
| 1277 | */ |
Linus Torvalds | 7813b94 | 2011-08-07 09:53:20 -0700 | [diff] [blame] | 1278 | static inline int should_follow_link(struct inode *inode, int follow) |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1279 | { |
| 1280 | if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) { |
| 1281 | if (likely(inode->i_op->follow_link)) |
| 1282 | return follow; |
| 1283 | |
| 1284 | /* This gets set once for the inode lifetime */ |
| 1285 | spin_lock(&inode->i_lock); |
| 1286 | inode->i_opflags |= IOP_NOFOLLOW; |
| 1287 | spin_unlock(&inode->i_lock); |
| 1288 | } |
| 1289 | return 0; |
| 1290 | } |
| 1291 | |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1292 | static inline int walk_component(struct nameidata *nd, struct path *path, |
| 1293 | struct qstr *name, int type, int follow) |
| 1294 | { |
| 1295 | struct inode *inode; |
| 1296 | int err; |
| 1297 | /* |
| 1298 | * "." and ".." are special - ".." especially so because it has |
| 1299 | * to be able to know about the current root directory and |
| 1300 | * parent relationships. |
| 1301 | */ |
| 1302 | if (unlikely(type != LAST_NORM)) |
| 1303 | return handle_dots(nd, type); |
| 1304 | err = do_lookup(nd, name, path, &inode); |
| 1305 | if (unlikely(err)) { |
| 1306 | terminate_walk(nd); |
| 1307 | return err; |
| 1308 | } |
| 1309 | if (!inode) { |
| 1310 | path_to_nameidata(path, nd); |
| 1311 | terminate_walk(nd); |
| 1312 | return -ENOENT; |
| 1313 | } |
Linus Torvalds | 7813b94 | 2011-08-07 09:53:20 -0700 | [diff] [blame] | 1314 | if (should_follow_link(inode, follow)) { |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 1315 | if (nd->flags & LOOKUP_RCU) { |
| 1316 | if (unlikely(unlazy_walk(nd, path->dentry))) { |
| 1317 | terminate_walk(nd); |
| 1318 | return -ECHILD; |
| 1319 | } |
| 1320 | } |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1321 | BUG_ON(inode != path->dentry->d_inode); |
| 1322 | return 1; |
| 1323 | } |
| 1324 | path_to_nameidata(path, nd); |
| 1325 | nd->inode = inode; |
| 1326 | return 0; |
| 1327 | } |
| 1328 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1329 | /* |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1330 | * This limits recursive symlink follows to 8, while |
| 1331 | * limiting consecutive symlinks to 40. |
| 1332 | * |
| 1333 | * Without that kind of total limit, nasty chains of consecutive |
| 1334 | * symlinks can cause almost arbitrarily long lookups. |
| 1335 | */ |
| 1336 | static inline int nested_symlink(struct path *path, struct nameidata *nd) |
| 1337 | { |
| 1338 | int res; |
| 1339 | |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1340 | if (unlikely(current->link_count >= MAX_NESTED_LINKS)) { |
| 1341 | path_put_conditional(path, nd); |
| 1342 | path_put(&nd->path); |
| 1343 | return -ELOOP; |
| 1344 | } |
Erez Zadok | 1a4022f | 2011-05-21 01:19:59 -0400 | [diff] [blame] | 1345 | BUG_ON(nd->depth >= MAX_NESTED_LINKS); |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1346 | |
| 1347 | nd->depth++; |
| 1348 | current->link_count++; |
| 1349 | |
| 1350 | do { |
| 1351 | struct path link = *path; |
| 1352 | void *cookie; |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 1353 | |
| 1354 | res = follow_link(&link, nd, &cookie); |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1355 | if (!res) |
| 1356 | res = walk_component(nd, path, &nd->last, |
| 1357 | nd->last_type, LOOKUP_FOLLOW); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 1358 | put_link(nd, &link, cookie); |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1359 | } while (res > 0); |
| 1360 | |
| 1361 | current->link_count--; |
| 1362 | nd->depth--; |
| 1363 | return res; |
| 1364 | } |
| 1365 | |
| 1366 | /* |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1367 | * We really don't want to look at inode->i_op->lookup |
| 1368 | * when we don't have to. So we keep a cache bit in |
| 1369 | * the inode ->i_opflags field that says "yes, we can |
| 1370 | * do lookup on this inode". |
| 1371 | */ |
| 1372 | static inline int can_lookup(struct inode *inode) |
| 1373 | { |
| 1374 | if (likely(inode->i_opflags & IOP_LOOKUP)) |
| 1375 | return 1; |
| 1376 | if (likely(!inode->i_op->lookup)) |
| 1377 | return 0; |
| 1378 | |
| 1379 | /* We do this once for the lifetime of the inode */ |
| 1380 | spin_lock(&inode->i_lock); |
| 1381 | inode->i_opflags |= IOP_LOOKUP; |
| 1382 | spin_unlock(&inode->i_lock); |
| 1383 | return 1; |
| 1384 | } |
| 1385 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1386 | /* |
| 1387 | * We can do the critical dentry name comparison and hashing |
| 1388 | * operations one word at a time, but we are limited to: |
| 1389 | * |
| 1390 | * - Architectures with fast unaligned word accesses. We could |
| 1391 | * do a "get_unaligned()" if this helps and is sufficiently |
| 1392 | * fast. |
| 1393 | * |
| 1394 | * - Little-endian machines (so that we can generate the mask |
| 1395 | * of low bytes efficiently). Again, we *could* do a byte |
| 1396 | * swapping load on big-endian architectures if that is not |
| 1397 | * expensive enough to make the optimization worthless. |
| 1398 | * |
| 1399 | * - non-CONFIG_DEBUG_PAGEALLOC configurations (so that we |
| 1400 | * do not trap on the (extremely unlikely) case of a page |
| 1401 | * crossing operation. |
| 1402 | * |
| 1403 | * - Furthermore, we need an efficient 64-bit compile for the |
| 1404 | * 64-bit case in order to generate the "number of bytes in |
| 1405 | * the final mask". Again, that could be replaced with a |
| 1406 | * efficient population count instruction or similar. |
| 1407 | */ |
| 1408 | #ifdef CONFIG_DCACHE_WORD_ACCESS |
| 1409 | |
Linus Torvalds | f68e556 | 2012-04-06 13:54:56 -0700 | [diff] [blame] | 1410 | #include <asm/word-at-a-time.h> |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1411 | |
Linus Torvalds | f68e556 | 2012-04-06 13:54:56 -0700 | [diff] [blame] | 1412 | #ifdef CONFIG_64BIT |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1413 | |
| 1414 | static inline unsigned int fold_hash(unsigned long hash) |
| 1415 | { |
| 1416 | hash += hash >> (8*sizeof(int)); |
| 1417 | return hash; |
| 1418 | } |
| 1419 | |
| 1420 | #else /* 32-bit case */ |
| 1421 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1422 | #define fold_hash(x) (x) |
| 1423 | |
| 1424 | #endif |
| 1425 | |
| 1426 | unsigned int full_name_hash(const unsigned char *name, unsigned int len) |
| 1427 | { |
| 1428 | unsigned long a, mask; |
| 1429 | unsigned long hash = 0; |
| 1430 | |
| 1431 | for (;;) { |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 1432 | a = load_unaligned_zeropad(name); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1433 | if (len < sizeof(unsigned long)) |
| 1434 | break; |
| 1435 | hash += a; |
Al Viro | f132c5b | 2012-03-22 21:59:52 +0000 | [diff] [blame] | 1436 | hash *= 9; |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1437 | name += sizeof(unsigned long); |
| 1438 | len -= sizeof(unsigned long); |
| 1439 | if (!len) |
| 1440 | goto done; |
| 1441 | } |
| 1442 | mask = ~(~0ul << len*8); |
| 1443 | hash += mask & a; |
| 1444 | done: |
| 1445 | return fold_hash(hash); |
| 1446 | } |
| 1447 | EXPORT_SYMBOL(full_name_hash); |
| 1448 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1449 | /* |
| 1450 | * Calculate the length and hash of the path component, and |
| 1451 | * return the length of the component; |
| 1452 | */ |
| 1453 | static inline unsigned long hash_name(const char *name, unsigned int *hashp) |
| 1454 | { |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1455 | unsigned long a, b, adata, bdata, mask, hash, len; |
| 1456 | const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1457 | |
| 1458 | hash = a = 0; |
| 1459 | len = -sizeof(unsigned long); |
| 1460 | do { |
| 1461 | hash = (hash + a) * 9; |
| 1462 | len += sizeof(unsigned long); |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 1463 | a = load_unaligned_zeropad(name+len); |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1464 | b = a ^ REPEAT_BYTE('/'); |
| 1465 | } while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants))); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1466 | |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1467 | adata = prep_zero_mask(a, adata, &constants); |
| 1468 | bdata = prep_zero_mask(b, bdata, &constants); |
| 1469 | |
| 1470 | mask = create_zero_mask(adata | bdata); |
| 1471 | |
| 1472 | hash += a & zero_bytemask(mask); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1473 | *hashp = fold_hash(hash); |
| 1474 | |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1475 | return len + find_zero(mask); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1476 | } |
| 1477 | |
| 1478 | #else |
| 1479 | |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 1480 | unsigned int full_name_hash(const unsigned char *name, unsigned int len) |
| 1481 | { |
| 1482 | unsigned long hash = init_name_hash(); |
| 1483 | while (len--) |
| 1484 | hash = partial_name_hash(*name++, hash); |
| 1485 | return end_name_hash(hash); |
| 1486 | } |
Linus Torvalds | ae942ae | 2012-03-02 19:40:57 -0800 | [diff] [blame] | 1487 | EXPORT_SYMBOL(full_name_hash); |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 1488 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1489 | /* |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1490 | * We know there's a real path component here of at least |
| 1491 | * one character. |
| 1492 | */ |
| 1493 | static inline unsigned long hash_name(const char *name, unsigned int *hashp) |
| 1494 | { |
| 1495 | unsigned long hash = init_name_hash(); |
| 1496 | unsigned long len = 0, c; |
| 1497 | |
| 1498 | c = (unsigned char)*name; |
| 1499 | do { |
| 1500 | len++; |
| 1501 | hash = partial_name_hash(c, hash); |
| 1502 | c = (unsigned char)name[len]; |
| 1503 | } while (c && c != '/'); |
| 1504 | *hashp = end_name_hash(hash); |
| 1505 | return len; |
| 1506 | } |
| 1507 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1508 | #endif |
| 1509 | |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1510 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1511 | * Name resolution. |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1512 | * This is the basic name resolution function, turning a pathname into |
| 1513 | * the final dentry. We expect 'base' to be positive and a directory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1514 | * |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1515 | * Returns 0 and nd will have valid dentry and mnt on success. |
| 1516 | * Returns error and drops reference to input namei data on failure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1517 | */ |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 1518 | static int link_path_walk(const char *name, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1519 | { |
| 1520 | struct path next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1521 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1522 | |
| 1523 | while (*name=='/') |
| 1524 | name++; |
| 1525 | if (!*name) |
Al Viro | 086e183 | 2011-02-22 20:56:27 -0500 | [diff] [blame] | 1526 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1527 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1528 | /* At this point we know we have a real path component. */ |
| 1529 | for(;;) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1530 | struct qstr this; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1531 | long len; |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1532 | int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1533 | |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1534 | err = may_lookup(nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1535 | if (err) |
| 1536 | break; |
| 1537 | |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1538 | len = hash_name(name, &this.hash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1539 | this.name = name; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1540 | this.len = len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1541 | |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1542 | type = LAST_NORM; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1543 | if (name[0] == '.') switch (len) { |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1544 | case 2: |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1545 | if (name[1] == '.') { |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1546 | type = LAST_DOTDOT; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1547 | nd->flags |= LOOKUP_JUMPED; |
| 1548 | } |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1549 | break; |
| 1550 | case 1: |
| 1551 | type = LAST_DOT; |
| 1552 | } |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1553 | if (likely(type == LAST_NORM)) { |
| 1554 | struct dentry *parent = nd->path.dentry; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1555 | nd->flags &= ~LOOKUP_JUMPED; |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1556 | if (unlikely(parent->d_flags & DCACHE_OP_HASH)) { |
| 1557 | err = parent->d_op->d_hash(parent, nd->inode, |
| 1558 | &this); |
| 1559 | if (err < 0) |
| 1560 | break; |
| 1561 | } |
| 1562 | } |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1563 | |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1564 | if (!name[len]) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1565 | goto last_component; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1566 | /* |
| 1567 | * If it wasn't NUL, we know it was '/'. Skip that |
| 1568 | * slash, and continue until no more slashes. |
| 1569 | */ |
| 1570 | do { |
| 1571 | len++; |
| 1572 | } while (unlikely(name[len] == '/')); |
| 1573 | if (!name[len]) |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1574 | goto last_component; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1575 | name += len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1576 | |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1577 | err = walk_component(nd, &next, &this, type, LOOKUP_FOLLOW); |
| 1578 | if (err < 0) |
| 1579 | return err; |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1580 | |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1581 | if (err) { |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1582 | err = nested_symlink(&next, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1583 | if (err) |
Al Viro | a7472ba | 2011-03-04 14:39:30 -0500 | [diff] [blame] | 1584 | return err; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1585 | } |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1586 | if (can_lookup(nd->inode)) |
| 1587 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1588 | err = -ENOTDIR; |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1589 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1590 | /* here ends the main loop */ |
| 1591 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1592 | last_component: |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1593 | nd->last = this; |
| 1594 | nd->last_type = type; |
Al Viro | 086e183 | 2011-02-22 20:56:27 -0500 | [diff] [blame] | 1595 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1596 | } |
Al Viro | 951361f | 2011-03-04 14:44:37 -0500 | [diff] [blame] | 1597 | terminate_walk(nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1598 | return err; |
| 1599 | } |
| 1600 | |
Al Viro | 70e9b35 | 2011-03-05 21:12:22 -0500 | [diff] [blame] | 1601 | static int path_init(int dfd, const char *name, unsigned int flags, |
| 1602 | struct nameidata *nd, struct file **fp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1603 | { |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1604 | int retval = 0; |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1605 | int fput_needed; |
| 1606 | struct file *file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1607 | |
| 1608 | nd->last_type = LAST_ROOT; /* if there are only slashes... */ |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1609 | nd->flags = flags | LOOKUP_JUMPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1610 | nd->depth = 0; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1611 | if (flags & LOOKUP_ROOT) { |
| 1612 | struct inode *inode = nd->root.dentry->d_inode; |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 1613 | if (*name) { |
| 1614 | if (!inode->i_op->lookup) |
| 1615 | return -ENOTDIR; |
| 1616 | retval = inode_permission(inode, MAY_EXEC); |
| 1617 | if (retval) |
| 1618 | return retval; |
| 1619 | } |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1620 | nd->path = nd->root; |
| 1621 | nd->inode = inode; |
| 1622 | if (flags & LOOKUP_RCU) { |
| 1623 | br_read_lock(vfsmount_lock); |
| 1624 | rcu_read_lock(); |
| 1625 | nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); |
| 1626 | } else { |
| 1627 | path_get(&nd->path); |
| 1628 | } |
| 1629 | return 0; |
| 1630 | } |
| 1631 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1632 | nd->root.mnt = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1633 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1634 | if (*name=='/') { |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1635 | if (flags & LOOKUP_RCU) { |
| 1636 | br_read_lock(vfsmount_lock); |
| 1637 | rcu_read_lock(); |
| 1638 | set_root_rcu(nd); |
| 1639 | } else { |
| 1640 | set_root(nd); |
| 1641 | path_get(&nd->root); |
| 1642 | } |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1643 | nd->path = nd->root; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1644 | } else if (dfd == AT_FDCWD) { |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1645 | if (flags & LOOKUP_RCU) { |
| 1646 | struct fs_struct *fs = current->fs; |
| 1647 | unsigned seq; |
| 1648 | |
| 1649 | br_read_lock(vfsmount_lock); |
| 1650 | rcu_read_lock(); |
| 1651 | |
| 1652 | do { |
| 1653 | seq = read_seqcount_begin(&fs->seq); |
| 1654 | nd->path = fs->pwd; |
| 1655 | nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); |
| 1656 | } while (read_seqcount_retry(&fs->seq, seq)); |
| 1657 | } else { |
| 1658 | get_fs_pwd(current->fs, &nd->path); |
| 1659 | } |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1660 | } else { |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1661 | struct dentry *dentry; |
| 1662 | |
Al Viro | 1abf0c7 | 2011-03-13 03:51:11 -0400 | [diff] [blame] | 1663 | file = fget_raw_light(dfd, &fput_needed); |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1664 | retval = -EBADF; |
| 1665 | if (!file) |
Trond Myklebust | 6d09bb6 | 2006-06-04 02:51:37 -0700 | [diff] [blame] | 1666 | goto out_fail; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1667 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1668 | dentry = file->f_path.dentry; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1669 | |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 1670 | if (*name) { |
| 1671 | retval = -ENOTDIR; |
| 1672 | if (!S_ISDIR(dentry->d_inode->i_mode)) |
| 1673 | goto fput_fail; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1674 | |
Al Viro | 4ad5abb | 2011-06-20 19:57:03 -0400 | [diff] [blame] | 1675 | retval = inode_permission(dentry->d_inode, MAY_EXEC); |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 1676 | if (retval) |
| 1677 | goto fput_fail; |
| 1678 | } |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1679 | |
Jan Blunck | 5dd784d0 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 1680 | nd->path = file->f_path; |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1681 | if (flags & LOOKUP_RCU) { |
| 1682 | if (fput_needed) |
Al Viro | 70e9b35 | 2011-03-05 21:12:22 -0500 | [diff] [blame] | 1683 | *fp = file; |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1684 | nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); |
| 1685 | br_read_lock(vfsmount_lock); |
| 1686 | rcu_read_lock(); |
| 1687 | } else { |
| 1688 | path_get(&file->f_path); |
| 1689 | fput_light(file, fput_needed); |
| 1690 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1691 | } |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1692 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1693 | nd->inode = nd->path.dentry->d_inode; |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1694 | return 0; |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1695 | |
Trond Myklebust | 6d09bb6 | 2006-06-04 02:51:37 -0700 | [diff] [blame] | 1696 | fput_fail: |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1697 | fput_light(file, fput_needed); |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1698 | out_fail: |
| 1699 | return retval; |
| 1700 | } |
| 1701 | |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1702 | static inline int lookup_last(struct nameidata *nd, struct path *path) |
| 1703 | { |
| 1704 | if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len]) |
| 1705 | nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
| 1706 | |
| 1707 | nd->flags &= ~LOOKUP_PARENT; |
| 1708 | return walk_component(nd, path, &nd->last, nd->last_type, |
| 1709 | nd->flags & LOOKUP_FOLLOW); |
| 1710 | } |
| 1711 | |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1712 | /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1713 | static int path_lookupat(int dfd, const char *name, |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1714 | unsigned int flags, struct nameidata *nd) |
| 1715 | { |
Al Viro | 70e9b35 | 2011-03-05 21:12:22 -0500 | [diff] [blame] | 1716 | struct file *base = NULL; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1717 | struct path path; |
| 1718 | int err; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1719 | |
| 1720 | /* |
| 1721 | * Path walking is largely split up into 2 different synchronisation |
| 1722 | * schemes, rcu-walk and ref-walk (explained in |
| 1723 | * Documentation/filesystems/path-lookup.txt). These share much of the |
| 1724 | * path walk code, but some things particularly setup, cleanup, and |
| 1725 | * following mounts are sufficiently divergent that functions are |
| 1726 | * duplicated. Typically there is a function foo(), and its RCU |
| 1727 | * analogue, foo_rcu(). |
| 1728 | * |
| 1729 | * -ECHILD is the error number of choice (just to avoid clashes) that |
| 1730 | * is returned if some aspect of an rcu-walk fails. Such an error must |
| 1731 | * be handled by restarting a traditional ref-walk (which will always |
| 1732 | * be able to complete). |
| 1733 | */ |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1734 | err = path_init(dfd, name, flags | LOOKUP_PARENT, nd, &base); |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1735 | |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1736 | if (unlikely(err)) |
| 1737 | return err; |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1738 | |
| 1739 | current->total_link_count = 0; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1740 | err = link_path_walk(name, nd); |
| 1741 | |
| 1742 | if (!err && !(flags & LOOKUP_PARENT)) { |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1743 | err = lookup_last(nd, &path); |
| 1744 | while (err > 0) { |
| 1745 | void *cookie; |
| 1746 | struct path link = path; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1747 | nd->flags |= LOOKUP_PARENT; |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 1748 | err = follow_link(&link, nd, &cookie); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1749 | if (!err) |
| 1750 | err = lookup_last(nd, &path); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 1751 | put_link(nd, &link, cookie); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1752 | } |
| 1753 | } |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1754 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 1755 | if (!err) |
| 1756 | err = complete_walk(nd); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1757 | |
| 1758 | if (!err && nd->flags & LOOKUP_DIRECTORY) { |
| 1759 | if (!nd->inode->i_op->lookup) { |
| 1760 | path_put(&nd->path); |
Al Viro | bd23a53 | 2011-03-23 09:56:30 -0400 | [diff] [blame] | 1761 | err = -ENOTDIR; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1762 | } |
| 1763 | } |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1764 | |
Al Viro | 70e9b35 | 2011-03-05 21:12:22 -0500 | [diff] [blame] | 1765 | if (base) |
| 1766 | fput(base); |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1767 | |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1768 | if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1769 | path_put(&nd->root); |
| 1770 | nd->root.mnt = NULL; |
| 1771 | } |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1772 | return err; |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1773 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1774 | |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1775 | static int do_path_lookup(int dfd, const char *name, |
| 1776 | unsigned int flags, struct nameidata *nd) |
| 1777 | { |
| 1778 | int retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd); |
| 1779 | if (unlikely(retval == -ECHILD)) |
| 1780 | retval = path_lookupat(dfd, name, flags, nd); |
| 1781 | if (unlikely(retval == -ESTALE)) |
| 1782 | retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1783 | |
| 1784 | if (likely(!retval)) { |
| 1785 | if (unlikely(!audit_dummy_context())) { |
| 1786 | if (nd->path.dentry && nd->inode) |
| 1787 | audit_inode(name, nd->path.dentry); |
| 1788 | } |
| 1789 | } |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1790 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1791 | } |
| 1792 | |
Al Viro | c9c6cac | 2011-02-16 15:15:47 -0500 | [diff] [blame] | 1793 | int kern_path_parent(const char *name, struct nameidata *nd) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1794 | { |
Al Viro | c9c6cac | 2011-02-16 15:15:47 -0500 | [diff] [blame] | 1795 | return do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, nd); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1796 | } |
| 1797 | |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 1798 | int kern_path(const char *name, unsigned int flags, struct path *path) |
| 1799 | { |
| 1800 | struct nameidata nd; |
| 1801 | int res = do_path_lookup(AT_FDCWD, name, flags, &nd); |
| 1802 | if (!res) |
| 1803 | *path = nd.path; |
| 1804 | return res; |
| 1805 | } |
| 1806 | |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1807 | /** |
| 1808 | * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair |
| 1809 | * @dentry: pointer to dentry of the base directory |
| 1810 | * @mnt: pointer to vfs mount of the base directory |
| 1811 | * @name: pointer to file name |
| 1812 | * @flags: lookup flags |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 1813 | * @path: pointer to struct path to fill |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1814 | */ |
| 1815 | int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, |
| 1816 | const char *name, unsigned int flags, |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 1817 | struct path *path) |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1818 | { |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 1819 | struct nameidata nd; |
| 1820 | int err; |
| 1821 | nd.root.dentry = dentry; |
| 1822 | nd.root.mnt = mnt; |
| 1823 | BUG_ON(flags & LOOKUP_PARENT); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1824 | /* the first argument of do_path_lookup() is ignored with LOOKUP_ROOT */ |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 1825 | err = do_path_lookup(AT_FDCWD, name, flags | LOOKUP_ROOT, &nd); |
| 1826 | if (!err) |
| 1827 | *path = nd.path; |
| 1828 | return err; |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1829 | } |
| 1830 | |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1831 | /* |
| 1832 | * Restricted form of lookup. Doesn't follow links, single-component only, |
| 1833 | * needs parent already locked. Doesn't follow mounts. |
| 1834 | * SMP-safe. |
| 1835 | */ |
Adrian Bunk | a244e16 | 2006-03-31 02:32:11 -0800 | [diff] [blame] | 1836 | static struct dentry *lookup_hash(struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1837 | { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1838 | return __lookup_hash(&nd->last, nd->path.dentry, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1839 | } |
| 1840 | |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1841 | /** |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 1842 | * lookup_one_len - filesystem helper to lookup single pathname component |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1843 | * @name: pathname component to lookup |
| 1844 | * @base: base directory to lookup from |
| 1845 | * @len: maximum length @len should be interpreted to |
| 1846 | * |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 1847 | * Note that this routine is purely a helper for filesystem usage and should |
| 1848 | * not be called by generic code. Also note that by using this function the |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1849 | * nameidata argument is passed to the filesystem methods and a filesystem |
| 1850 | * using this helper needs to be prepared for that. |
| 1851 | */ |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1852 | struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) |
| 1853 | { |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1854 | struct qstr this; |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 1855 | unsigned int c; |
Miklos Szeredi | cda309d | 2012-03-26 12:54:21 +0200 | [diff] [blame] | 1856 | int err; |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1857 | |
David Woodhouse | 2f9092e | 2009-04-20 23:18:37 +0100 | [diff] [blame] | 1858 | WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); |
| 1859 | |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 1860 | this.name = name; |
| 1861 | this.len = len; |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 1862 | this.hash = full_name_hash(name, len); |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 1863 | if (!len) |
| 1864 | return ERR_PTR(-EACCES); |
| 1865 | |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 1866 | while (len--) { |
| 1867 | c = *(const unsigned char *)name++; |
| 1868 | if (c == '/' || c == '\0') |
| 1869 | return ERR_PTR(-EACCES); |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 1870 | } |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1871 | /* |
| 1872 | * See if the low-level filesystem might want |
| 1873 | * to use its own hash.. |
| 1874 | */ |
| 1875 | if (base->d_flags & DCACHE_OP_HASH) { |
| 1876 | int err = base->d_op->d_hash(base, base->d_inode, &this); |
| 1877 | if (err < 0) |
| 1878 | return ERR_PTR(err); |
| 1879 | } |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1880 | |
Miklos Szeredi | cda309d | 2012-03-26 12:54:21 +0200 | [diff] [blame] | 1881 | err = inode_permission(base->d_inode, MAY_EXEC); |
| 1882 | if (err) |
| 1883 | return ERR_PTR(err); |
| 1884 | |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 1885 | return __lookup_hash(&this, base, NULL); |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1886 | } |
| 1887 | |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 1888 | int user_path_at_empty(int dfd, const char __user *name, unsigned flags, |
| 1889 | struct path *path, int *empty) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1890 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1891 | struct nameidata nd; |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 1892 | char *tmp = getname_flags(name, flags, empty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1893 | int err = PTR_ERR(tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1894 | if (!IS_ERR(tmp)) { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1895 | |
| 1896 | BUG_ON(flags & LOOKUP_PARENT); |
| 1897 | |
| 1898 | err = do_path_lookup(dfd, tmp, flags, &nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1899 | putname(tmp); |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1900 | if (!err) |
| 1901 | *path = nd.path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1902 | } |
| 1903 | return err; |
| 1904 | } |
| 1905 | |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 1906 | int user_path_at(int dfd, const char __user *name, unsigned flags, |
| 1907 | struct path *path) |
| 1908 | { |
Linus Torvalds | f7493e5 | 2012-03-22 16:10:40 -0700 | [diff] [blame] | 1909 | return user_path_at_empty(dfd, name, flags, path, NULL); |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 1910 | } |
| 1911 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 1912 | static int user_path_parent(int dfd, const char __user *path, |
| 1913 | struct nameidata *nd, char **name) |
| 1914 | { |
| 1915 | char *s = getname(path); |
| 1916 | int error; |
| 1917 | |
| 1918 | if (IS_ERR(s)) |
| 1919 | return PTR_ERR(s); |
| 1920 | |
| 1921 | error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd); |
| 1922 | if (error) |
| 1923 | putname(s); |
| 1924 | else |
| 1925 | *name = s; |
| 1926 | |
| 1927 | return error; |
| 1928 | } |
| 1929 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1930 | /* |
| 1931 | * It's inline, so penalty for filesystems that don't use sticky bit is |
| 1932 | * minimal. |
| 1933 | */ |
| 1934 | static inline int check_sticky(struct inode *dir, struct inode *inode) |
| 1935 | { |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 1936 | kuid_t fsuid = current_fsuid(); |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 1937 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1938 | if (!(dir->i_mode & S_ISVTX)) |
| 1939 | return 0; |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 1940 | if (uid_eq(inode->i_uid, fsuid)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1941 | return 0; |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 1942 | if (uid_eq(dir->i_uid, fsuid)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1943 | return 0; |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 1944 | return !inode_capable(inode, CAP_FOWNER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1945 | } |
| 1946 | |
| 1947 | /* |
| 1948 | * Check whether we can remove a link victim from directory dir, check |
| 1949 | * whether the type of victim is right. |
| 1950 | * 1. We can't do it if dir is read-only (done in permission()) |
| 1951 | * 2. We should have write and exec permissions on dir |
| 1952 | * 3. We can't remove anything from append-only dir |
| 1953 | * 4. We can't do anything with immutable dir (done in permission()) |
| 1954 | * 5. If the sticky bit on dir is set we should either |
| 1955 | * a. be owner of dir, or |
| 1956 | * b. be owner of victim, or |
| 1957 | * c. have CAP_FOWNER capability |
| 1958 | * 6. If the victim is append-only or immutable we can't do antyhing with |
| 1959 | * links pointing to it. |
| 1960 | * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. |
| 1961 | * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. |
| 1962 | * 9. We can't remove a root or mountpoint. |
| 1963 | * 10. We don't allow removal of NFS sillyrenamed files; it's handled by |
| 1964 | * nfs_async_unlink(). |
| 1965 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 1966 | static int may_delete(struct inode *dir,struct dentry *victim,int isdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1967 | { |
| 1968 | int error; |
| 1969 | |
| 1970 | if (!victim->d_inode) |
| 1971 | return -ENOENT; |
| 1972 | |
| 1973 | BUG_ON(victim->d_parent->d_inode != dir); |
Al Viro | cccc6bb | 2009-12-25 05:07:33 -0500 | [diff] [blame] | 1974 | audit_inode_child(victim, dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1975 | |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 1976 | error = inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1977 | if (error) |
| 1978 | return error; |
| 1979 | if (IS_APPEND(dir)) |
| 1980 | return -EPERM; |
| 1981 | if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| |
Hugh Dickins | f945454 | 2008-11-19 15:36:38 -0800 | [diff] [blame] | 1982 | IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1983 | return -EPERM; |
| 1984 | if (isdir) { |
| 1985 | if (!S_ISDIR(victim->d_inode->i_mode)) |
| 1986 | return -ENOTDIR; |
| 1987 | if (IS_ROOT(victim)) |
| 1988 | return -EBUSY; |
| 1989 | } else if (S_ISDIR(victim->d_inode->i_mode)) |
| 1990 | return -EISDIR; |
| 1991 | if (IS_DEADDIR(dir)) |
| 1992 | return -ENOENT; |
| 1993 | if (victim->d_flags & DCACHE_NFSFS_RENAMED) |
| 1994 | return -EBUSY; |
| 1995 | return 0; |
| 1996 | } |
| 1997 | |
| 1998 | /* Check whether we can create an object with dentry child in directory |
| 1999 | * dir. |
| 2000 | * 1. We can't do it if child already exists (open has special treatment for |
| 2001 | * this case, but since we are inlined it's OK) |
| 2002 | * 2. We can't do it if dir is read-only (done in permission()) |
| 2003 | * 3. We should have write and exec permissions on dir |
| 2004 | * 4. We can't do it if dir is immutable (done in permission()) |
| 2005 | */ |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2006 | static inline int may_create(struct inode *dir, struct dentry *child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2007 | { |
| 2008 | if (child->d_inode) |
| 2009 | return -EEXIST; |
| 2010 | if (IS_DEADDIR(dir)) |
| 2011 | return -ENOENT; |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 2012 | return inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2013 | } |
| 2014 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2015 | /* |
| 2016 | * p1 and p2 should be directories on the same fs. |
| 2017 | */ |
| 2018 | struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) |
| 2019 | { |
| 2020 | struct dentry *p; |
| 2021 | |
| 2022 | if (p1 == p2) { |
Ingo Molnar | f2eace2 | 2006-07-03 00:25:05 -0700 | [diff] [blame] | 2023 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2024 | return NULL; |
| 2025 | } |
| 2026 | |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 2027 | mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2028 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2029 | p = d_ancestor(p2, p1); |
| 2030 | if (p) { |
| 2031 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2032 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); |
| 2033 | return p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2034 | } |
| 2035 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2036 | p = d_ancestor(p1, p2); |
| 2037 | if (p) { |
| 2038 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2039 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); |
| 2040 | return p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2041 | } |
| 2042 | |
Ingo Molnar | f2eace2 | 2006-07-03 00:25:05 -0700 | [diff] [blame] | 2043 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2044 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2045 | return NULL; |
| 2046 | } |
| 2047 | |
| 2048 | void unlock_rename(struct dentry *p1, struct dentry *p2) |
| 2049 | { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2050 | mutex_unlock(&p1->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2051 | if (p1 != p2) { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2052 | mutex_unlock(&p2->d_inode->i_mutex); |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 2053 | mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2054 | } |
| 2055 | } |
| 2056 | |
Al Viro | 4acdaf2 | 2011-07-26 01:42:34 -0400 | [diff] [blame] | 2057 | int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2058 | struct nameidata *nd) |
| 2059 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2060 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2061 | |
| 2062 | if (error) |
| 2063 | return error; |
| 2064 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2065 | if (!dir->i_op->create) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2066 | return -EACCES; /* shouldn't it be ENOSYS? */ |
| 2067 | mode &= S_IALLUGO; |
| 2068 | mode |= S_IFREG; |
| 2069 | error = security_inode_create(dir, dentry, mode); |
| 2070 | if (error) |
| 2071 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2072 | error = dir->i_op->create(dir, dentry, mode, nd); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 2073 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 2074 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2075 | return error; |
| 2076 | } |
| 2077 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2078 | static int may_open(struct path *path, int acc_mode, int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2079 | { |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2080 | struct dentry *dentry = path->dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2081 | struct inode *inode = dentry->d_inode; |
| 2082 | int error; |
| 2083 | |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2084 | /* O_PATH? */ |
| 2085 | if (!acc_mode) |
| 2086 | return 0; |
| 2087 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2088 | if (!inode) |
| 2089 | return -ENOENT; |
| 2090 | |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2091 | switch (inode->i_mode & S_IFMT) { |
| 2092 | case S_IFLNK: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2093 | return -ELOOP; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2094 | case S_IFDIR: |
| 2095 | if (acc_mode & MAY_WRITE) |
| 2096 | return -EISDIR; |
| 2097 | break; |
| 2098 | case S_IFBLK: |
| 2099 | case S_IFCHR: |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2100 | if (path->mnt->mnt_flags & MNT_NODEV) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2101 | return -EACCES; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2102 | /*FALLTHRU*/ |
| 2103 | case S_IFIFO: |
| 2104 | case S_IFSOCK: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2105 | flag &= ~O_TRUNC; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2106 | break; |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 2107 | } |
Dave Hansen | b41572e | 2007-10-16 23:31:14 -0700 | [diff] [blame] | 2108 | |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2109 | error = inode_permission(inode, acc_mode); |
Dave Hansen | b41572e | 2007-10-16 23:31:14 -0700 | [diff] [blame] | 2110 | if (error) |
| 2111 | return error; |
Mimi Zohar | 6146f0d | 2009-02-04 09:06:57 -0500 | [diff] [blame] | 2112 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2113 | /* |
| 2114 | * An append-only file must be opened in append mode for writing. |
| 2115 | */ |
| 2116 | if (IS_APPEND(inode)) { |
Al Viro | 8737c93 | 2009-12-24 06:47:55 -0500 | [diff] [blame] | 2117 | if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2118 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2119 | if (flag & O_TRUNC) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2120 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2121 | } |
| 2122 | |
| 2123 | /* O_NOATIME can only be set by the owner or superuser */ |
Serge E. Hallyn | 2e14967 | 2011-03-23 16:43:26 -0700 | [diff] [blame] | 2124 | if (flag & O_NOATIME && !inode_owner_or_capable(inode)) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2125 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2126 | |
J. Bruce Fields | f3c7691e | 2011-09-21 10:58:13 -0400 | [diff] [blame] | 2127 | return 0; |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2128 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2129 | |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2130 | static int handle_truncate(struct file *filp) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2131 | { |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2132 | struct path *path = &filp->f_path; |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2133 | struct inode *inode = path->dentry->d_inode; |
| 2134 | int error = get_write_access(inode); |
| 2135 | if (error) |
| 2136 | return error; |
| 2137 | /* |
| 2138 | * Refuse to truncate files with mandatory locks held on them. |
| 2139 | */ |
| 2140 | error = locks_verify_locked(inode); |
| 2141 | if (!error) |
Tetsuo Handa | ea0d3ab | 2010-06-02 13:24:43 +0900 | [diff] [blame] | 2142 | error = security_path_truncate(path); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2143 | if (!error) { |
| 2144 | error = do_truncate(path->dentry, 0, |
| 2145 | ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2146 | filp); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2147 | } |
| 2148 | put_write_access(inode); |
Mimi Zohar | acd0c93 | 2009-09-04 13:08:46 -0400 | [diff] [blame] | 2149 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2150 | } |
| 2151 | |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 2152 | static inline int open_to_namei_flags(int flag) |
| 2153 | { |
Al Viro | 8a5e929 | 2011-06-25 19:15:54 -0400 | [diff] [blame] | 2154 | if ((flag & O_ACCMODE) == 3) |
| 2155 | flag--; |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 2156 | return flag; |
| 2157 | } |
| 2158 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2159 | /* |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2160 | * Handle the last step of open() |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2161 | */ |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2162 | static struct file *do_last(struct nameidata *nd, struct path *path, |
Al Viro | c3e380b | 2011-02-23 13:39:45 -0500 | [diff] [blame] | 2163 | const struct open_flags *op, const char *pathname) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2164 | { |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 2165 | struct dentry *dir = nd->path.dentry; |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2166 | struct dentry *dentry; |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2167 | int open_flag = op->open_flag; |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2168 | int will_truncate = open_flag & O_TRUNC; |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2169 | int want_write = 0; |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2170 | int acc_mode = op->acc_mode; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2171 | struct file *filp; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 2172 | int error; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2173 | |
Al Viro | c3e380b | 2011-02-23 13:39:45 -0500 | [diff] [blame] | 2174 | nd->flags &= ~LOOKUP_PARENT; |
| 2175 | nd->flags |= op->intent; |
| 2176 | |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 2177 | switch (nd->last_type) { |
| 2178 | case LAST_DOTDOT: |
Neil Brown | 176306f | 2010-05-24 16:57:56 +1000 | [diff] [blame] | 2179 | case LAST_DOT: |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2180 | error = handle_dots(nd, nd->last_type); |
| 2181 | if (error) |
| 2182 | return ERR_PTR(error); |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 2183 | /* fallthrough */ |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 2184 | case LAST_ROOT: |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 2185 | error = complete_walk(nd); |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 2186 | if (error) |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 2187 | return ERR_PTR(error); |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2188 | audit_inode(pathname, nd->path.dentry); |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2189 | if (open_flag & O_CREAT) { |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2190 | error = -EISDIR; |
| 2191 | goto exit; |
| 2192 | } |
| 2193 | goto ok; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 2194 | case LAST_BIND: |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 2195 | error = complete_walk(nd); |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 2196 | if (error) |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 2197 | return ERR_PTR(error); |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 2198 | audit_inode(pathname, dir); |
Al Viro | 67ee3ad | 2009-12-26 07:01:01 -0500 | [diff] [blame] | 2199 | goto ok; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 2200 | } |
Al Viro | 67ee3ad | 2009-12-26 07:01:01 -0500 | [diff] [blame] | 2201 | |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2202 | if (!(open_flag & O_CREAT)) { |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2203 | int symlink_ok = 0; |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2204 | if (nd->last.name[nd->last.len]) |
| 2205 | nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2206 | if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW)) |
| 2207 | symlink_ok = 1; |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2208 | /* we _can_ be in RCU mode here */ |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 2209 | error = walk_component(nd, path, &nd->last, LAST_NORM, |
| 2210 | !symlink_ok); |
| 2211 | if (error < 0) |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2212 | return ERR_PTR(error); |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 2213 | if (error) /* symlink */ |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2214 | return NULL; |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2215 | /* sayonara */ |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 2216 | error = complete_walk(nd); |
| 2217 | if (error) |
Miklos Szeredi | 7f6c7e6 | 2012-03-06 13:56:34 +0100 | [diff] [blame] | 2218 | return ERR_PTR(error); |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2219 | |
| 2220 | error = -ENOTDIR; |
| 2221 | if (nd->flags & LOOKUP_DIRECTORY) { |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 2222 | if (!nd->inode->i_op->lookup) |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2223 | goto exit; |
| 2224 | } |
| 2225 | audit_inode(pathname, nd->path.dentry); |
| 2226 | goto ok; |
| 2227 | } |
| 2228 | |
| 2229 | /* create side of things */ |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 2230 | /* |
| 2231 | * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED has been |
| 2232 | * cleared when we got to the last component we are about to look up |
| 2233 | */ |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 2234 | error = complete_walk(nd); |
| 2235 | if (error) |
| 2236 | return ERR_PTR(error); |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2237 | |
| 2238 | audit_inode(pathname, dir); |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 2239 | error = -EISDIR; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 2240 | /* trailing slashes? */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2241 | if (nd->last.name[nd->last.len]) |
| 2242 | goto exit; |
Al Viro | a2c36b4 | 2009-12-24 03:39:50 -0500 | [diff] [blame] | 2243 | |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 2244 | mutex_lock(&dir->d_inode->i_mutex); |
| 2245 | |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2246 | dentry = lookup_hash(nd); |
| 2247 | error = PTR_ERR(dentry); |
| 2248 | if (IS_ERR(dentry)) { |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2249 | mutex_unlock(&dir->d_inode->i_mutex); |
| 2250 | goto exit; |
| 2251 | } |
| 2252 | |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2253 | path->dentry = dentry; |
| 2254 | path->mnt = nd->path.mnt; |
| 2255 | |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2256 | /* Negative dentry, just create the file */ |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2257 | if (!dentry->d_inode) { |
Al Viro | a218d0f | 2011-11-21 14:59:34 -0500 | [diff] [blame] | 2258 | umode_t mode = op->mode; |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2259 | if (!IS_POSIXACL(dir->d_inode)) |
| 2260 | mode &= ~current_umask(); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2261 | /* |
| 2262 | * This write is needed to ensure that a |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2263 | * rw->ro transition does not occur between |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2264 | * the time when the file is created and when |
| 2265 | * a permanent write count is taken through |
| 2266 | * the 'struct file' in nameidata_to_filp(). |
| 2267 | */ |
| 2268 | error = mnt_want_write(nd->path.mnt); |
| 2269 | if (error) |
| 2270 | goto exit_mutex_unlock; |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2271 | want_write = 1; |
Al Viro | 9b44f1b | 2011-03-09 00:17:27 -0500 | [diff] [blame] | 2272 | /* Don't check for write permission, don't truncate */ |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2273 | open_flag &= ~O_TRUNC; |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2274 | will_truncate = 0; |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2275 | acc_mode = MAY_OPEN; |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2276 | error = security_path_mknod(&nd->path, dentry, mode, 0); |
| 2277 | if (error) |
| 2278 | goto exit_mutex_unlock; |
| 2279 | error = vfs_create(dir->d_inode, dentry, mode, nd); |
| 2280 | if (error) |
| 2281 | goto exit_mutex_unlock; |
| 2282 | mutex_unlock(&dir->d_inode->i_mutex); |
| 2283 | dput(nd->path.dentry); |
| 2284 | nd->path.dentry = dentry; |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2285 | goto common; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2286 | } |
| 2287 | |
| 2288 | /* |
| 2289 | * It already exists. |
| 2290 | */ |
| 2291 | mutex_unlock(&dir->d_inode->i_mutex); |
| 2292 | audit_inode(pathname, path->dentry); |
| 2293 | |
| 2294 | error = -EEXIST; |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2295 | if (open_flag & O_EXCL) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2296 | goto exit_dput; |
| 2297 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 2298 | error = follow_managed(path, nd->flags); |
| 2299 | if (error < 0) |
| 2300 | goto exit_dput; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2301 | |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 2302 | if (error) |
| 2303 | nd->flags |= LOOKUP_JUMPED; |
| 2304 | |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2305 | error = -ENOENT; |
| 2306 | if (!path->dentry->d_inode) |
| 2307 | goto exit_dput; |
Al Viro | 9e67f36 | 2009-12-26 07:04:50 -0500 | [diff] [blame] | 2308 | |
| 2309 | if (path->dentry->d_inode->i_op->follow_link) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2310 | return NULL; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2311 | |
| 2312 | path_to_nameidata(path, nd); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2313 | nd->inode = path->dentry->d_inode; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 2314 | /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */ |
| 2315 | error = complete_walk(nd); |
| 2316 | if (error) |
Miklos Szeredi | 097b180 | 2012-03-06 13:56:33 +0100 | [diff] [blame] | 2317 | return ERR_PTR(error); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2318 | error = -EISDIR; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2319 | if (S_ISDIR(nd->inode->i_mode)) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2320 | goto exit; |
Al Viro | 67ee3ad | 2009-12-26 07:01:01 -0500 | [diff] [blame] | 2321 | ok: |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2322 | if (!S_ISREG(nd->inode->i_mode)) |
| 2323 | will_truncate = 0; |
| 2324 | |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2325 | if (will_truncate) { |
| 2326 | error = mnt_want_write(nd->path.mnt); |
| 2327 | if (error) |
| 2328 | goto exit; |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2329 | want_write = 1; |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2330 | } |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2331 | common: |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2332 | error = may_open(&nd->path, acc_mode, open_flag); |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2333 | if (error) |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2334 | goto exit; |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2335 | filp = nameidata_to_filp(nd); |
| 2336 | if (!IS_ERR(filp)) { |
| 2337 | error = ima_file_check(filp, op->acc_mode); |
| 2338 | if (error) { |
| 2339 | fput(filp); |
| 2340 | filp = ERR_PTR(error); |
| 2341 | } |
| 2342 | } |
| 2343 | if (!IS_ERR(filp)) { |
| 2344 | if (will_truncate) { |
| 2345 | error = handle_truncate(filp); |
| 2346 | if (error) { |
| 2347 | fput(filp); |
| 2348 | filp = ERR_PTR(error); |
| 2349 | } |
| 2350 | } |
| 2351 | } |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2352 | out: |
| 2353 | if (want_write) |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2354 | mnt_drop_write(nd->path.mnt); |
| 2355 | path_put(&nd->path); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2356 | return filp; |
| 2357 | |
| 2358 | exit_mutex_unlock: |
| 2359 | mutex_unlock(&dir->d_inode->i_mutex); |
| 2360 | exit_dput: |
| 2361 | path_put_conditional(path, nd); |
| 2362 | exit: |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2363 | filp = ERR_PTR(error); |
| 2364 | goto out; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2365 | } |
| 2366 | |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2367 | static struct file *path_openat(int dfd, const char *pathname, |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2368 | struct nameidata *nd, const struct open_flags *op, int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2369 | { |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2370 | struct file *base = NULL; |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 2371 | struct file *filp; |
Al Viro | 9850c05 | 2010-01-13 15:01:15 -0500 | [diff] [blame] | 2372 | struct path path; |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2373 | int error; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2374 | |
| 2375 | filp = get_empty_filp(); |
| 2376 | if (!filp) |
| 2377 | return ERR_PTR(-ENFILE); |
| 2378 | |
Al Viro | 47c805d | 2011-02-23 17:44:09 -0500 | [diff] [blame] | 2379 | filp->f_flags = op->open_flag; |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2380 | nd->intent.open.file = filp; |
| 2381 | nd->intent.open.flags = open_to_namei_flags(op->open_flag); |
| 2382 | nd->intent.open.create_mode = op->mode; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2383 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2384 | error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2385 | if (unlikely(error)) |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2386 | goto out_filp; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2387 | |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2388 | current->total_link_count = 0; |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2389 | error = link_path_walk(pathname, nd); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2390 | if (unlikely(error)) |
| 2391 | goto out_filp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2392 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2393 | filp = do_last(nd, &path, op, pathname); |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 2394 | while (unlikely(!filp)) { /* trailing symlink */ |
Nick Piggin | 7b9337a | 2011-01-14 08:42:43 +0000 | [diff] [blame] | 2395 | struct path link = path; |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 2396 | void *cookie; |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 2397 | if (!(nd->flags & LOOKUP_FOLLOW)) { |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2398 | path_put_conditional(&path, nd); |
| 2399 | path_put(&nd->path); |
Al Viro | 40b3913 | 2011-03-09 16:22:18 -0500 | [diff] [blame] | 2400 | filp = ERR_PTR(-ELOOP); |
| 2401 | break; |
| 2402 | } |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2403 | nd->flags |= LOOKUP_PARENT; |
| 2404 | nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 2405 | error = follow_link(&link, nd, &cookie); |
Al Viro | c3e380b | 2011-02-23 13:39:45 -0500 | [diff] [blame] | 2406 | if (unlikely(error)) |
Al Viro | f1afe9e | 2011-02-22 22:27:28 -0500 | [diff] [blame] | 2407 | filp = ERR_PTR(error); |
Al Viro | c3e380b | 2011-02-23 13:39:45 -0500 | [diff] [blame] | 2408 | else |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2409 | filp = do_last(nd, &path, op, pathname); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 2410 | put_link(nd, &link, cookie); |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 2411 | } |
Al Viro | 10fa8e6 | 2009-12-26 07:09:49 -0500 | [diff] [blame] | 2412 | out: |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2413 | if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) |
| 2414 | path_put(&nd->root); |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2415 | if (base) |
| 2416 | fput(base); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2417 | release_open_intent(nd); |
Al Viro | 10fa8e6 | 2009-12-26 07:09:49 -0500 | [diff] [blame] | 2418 | return filp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2419 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2420 | out_filp: |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 2421 | filp = ERR_PTR(error); |
Al Viro | 10fa8e6 | 2009-12-26 07:09:49 -0500 | [diff] [blame] | 2422 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2423 | } |
| 2424 | |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2425 | struct file *do_filp_open(int dfd, const char *pathname, |
| 2426 | const struct open_flags *op, int flags) |
| 2427 | { |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2428 | struct nameidata nd; |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2429 | struct file *filp; |
| 2430 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2431 | filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2432 | if (unlikely(filp == ERR_PTR(-ECHILD))) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2433 | filp = path_openat(dfd, pathname, &nd, op, flags); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2434 | if (unlikely(filp == ERR_PTR(-ESTALE))) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2435 | filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_REVAL); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2436 | return filp; |
| 2437 | } |
| 2438 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2439 | struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, |
| 2440 | const char *name, const struct open_flags *op, int flags) |
| 2441 | { |
| 2442 | struct nameidata nd; |
| 2443 | struct file *file; |
| 2444 | |
| 2445 | nd.root.mnt = mnt; |
| 2446 | nd.root.dentry = dentry; |
| 2447 | |
| 2448 | flags |= LOOKUP_ROOT; |
| 2449 | |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2450 | if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2451 | return ERR_PTR(-ELOOP); |
| 2452 | |
| 2453 | file = path_openat(-1, name, &nd, op, flags | LOOKUP_RCU); |
| 2454 | if (unlikely(file == ERR_PTR(-ECHILD))) |
| 2455 | file = path_openat(-1, name, &nd, op, flags); |
| 2456 | if (unlikely(file == ERR_PTR(-ESTALE))) |
| 2457 | file = path_openat(-1, name, &nd, op, flags | LOOKUP_REVAL); |
| 2458 | return file; |
| 2459 | } |
| 2460 | |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 2461 | struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2462 | { |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 2463 | struct dentry *dentry = ERR_PTR(-EEXIST); |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 2464 | struct nameidata nd; |
| 2465 | int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd); |
| 2466 | if (error) |
| 2467 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2468 | |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 2469 | /* |
| 2470 | * Yucky last component or no last component at all? |
| 2471 | * (foo/., foo/.., /////) |
| 2472 | */ |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 2473 | if (nd.last_type != LAST_NORM) |
| 2474 | goto out; |
| 2475 | nd.flags &= ~LOOKUP_PARENT; |
| 2476 | nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL; |
| 2477 | nd.intent.open.flags = O_EXCL; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 2478 | |
| 2479 | /* |
| 2480 | * Do the final lookup. |
| 2481 | */ |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 2482 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2483 | dentry = lookup_hash(&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2484 | if (IS_ERR(dentry)) |
| 2485 | goto fail; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 2486 | |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 2487 | if (dentry->d_inode) |
| 2488 | goto eexist; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 2489 | /* |
| 2490 | * Special case - lookup gave negative, but... we had foo/bar/ |
| 2491 | * From the vfs_mknod() POV we just have a negative dentry - |
| 2492 | * all is fine. Let's be bastards - you had / on the end, you've |
| 2493 | * been asking for (non-existent) directory. -ENOENT for you. |
| 2494 | */ |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 2495 | if (unlikely(!is_dir && nd.last.name[nd.last.len])) { |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 2496 | dput(dentry); |
| 2497 | dentry = ERR_PTR(-ENOENT); |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 2498 | goto fail; |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 2499 | } |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 2500 | *path = nd.path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2501 | return dentry; |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 2502 | eexist: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2503 | dput(dentry); |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 2504 | dentry = ERR_PTR(-EEXIST); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2505 | fail: |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 2506 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
| 2507 | out: |
| 2508 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2509 | return dentry; |
| 2510 | } |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2511 | EXPORT_SYMBOL(kern_path_create); |
| 2512 | |
| 2513 | struct dentry *user_path_create(int dfd, const char __user *pathname, struct path *path, int is_dir) |
| 2514 | { |
| 2515 | char *tmp = getname(pathname); |
| 2516 | struct dentry *res; |
| 2517 | if (IS_ERR(tmp)) |
| 2518 | return ERR_CAST(tmp); |
| 2519 | res = kern_path_create(dfd, tmp, path, is_dir); |
| 2520 | putname(tmp); |
| 2521 | return res; |
| 2522 | } |
| 2523 | EXPORT_SYMBOL(user_path_create); |
| 2524 | |
Al Viro | 1a67aaf | 2011-07-26 01:52:52 -0400 | [diff] [blame] | 2525 | int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2526 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2527 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2528 | |
| 2529 | if (error) |
| 2530 | return error; |
| 2531 | |
Eric W. Biederman | 975d6b3 | 2011-11-13 12:16:43 -0800 | [diff] [blame] | 2532 | if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2533 | return -EPERM; |
| 2534 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2535 | if (!dir->i_op->mknod) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2536 | return -EPERM; |
| 2537 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 2538 | error = devcgroup_inode_mknod(mode, dev); |
| 2539 | if (error) |
| 2540 | return error; |
| 2541 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2542 | error = security_inode_mknod(dir, dentry, mode, dev); |
| 2543 | if (error) |
| 2544 | return error; |
| 2545 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2546 | error = dir->i_op->mknod(dir, dentry, mode, dev); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 2547 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 2548 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2549 | return error; |
| 2550 | } |
| 2551 | |
Al Viro | f69aac0 | 2011-07-26 04:31:40 -0400 | [diff] [blame] | 2552 | static int may_mknod(umode_t mode) |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2553 | { |
| 2554 | switch (mode & S_IFMT) { |
| 2555 | case S_IFREG: |
| 2556 | case S_IFCHR: |
| 2557 | case S_IFBLK: |
| 2558 | case S_IFIFO: |
| 2559 | case S_IFSOCK: |
| 2560 | case 0: /* zero mode translates to S_IFREG */ |
| 2561 | return 0; |
| 2562 | case S_IFDIR: |
| 2563 | return -EPERM; |
| 2564 | default: |
| 2565 | return -EINVAL; |
| 2566 | } |
| 2567 | } |
| 2568 | |
Al Viro | 8208a22 | 2011-07-25 17:32:17 -0400 | [diff] [blame] | 2569 | SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 2570 | unsigned, dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2571 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2572 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2573 | struct path path; |
| 2574 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2575 | |
| 2576 | if (S_ISDIR(mode)) |
| 2577 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2578 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2579 | dentry = user_path_create(dfd, filename, &path, 0); |
| 2580 | if (IS_ERR(dentry)) |
| 2581 | return PTR_ERR(dentry); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2582 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2583 | if (!IS_POSIXACL(path.dentry->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 2584 | mode &= ~current_umask(); |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2585 | error = may_mknod(mode); |
| 2586 | if (error) |
| 2587 | goto out_dput; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2588 | error = mnt_want_write(path.mnt); |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2589 | if (error) |
| 2590 | goto out_dput; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2591 | error = security_path_mknod(&path, dentry, mode, dev); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2592 | if (error) |
| 2593 | goto out_drop_write; |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2594 | switch (mode & S_IFMT) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2595 | case 0: case S_IFREG: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2596 | error = vfs_create(path.dentry->d_inode,dentry,mode,NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2597 | break; |
| 2598 | case S_IFCHR: case S_IFBLK: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2599 | error = vfs_mknod(path.dentry->d_inode,dentry,mode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2600 | new_decode_dev(dev)); |
| 2601 | break; |
| 2602 | case S_IFIFO: case S_IFSOCK: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2603 | error = vfs_mknod(path.dentry->d_inode,dentry,mode,0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2604 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2605 | } |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2606 | out_drop_write: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2607 | mnt_drop_write(path.mnt); |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2608 | out_dput: |
| 2609 | dput(dentry); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2610 | mutex_unlock(&path.dentry->d_inode->i_mutex); |
| 2611 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2612 | |
| 2613 | return error; |
| 2614 | } |
| 2615 | |
Al Viro | 8208a22 | 2011-07-25 17:32:17 -0400 | [diff] [blame] | 2616 | SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2617 | { |
| 2618 | return sys_mknodat(AT_FDCWD, filename, mode, dev); |
| 2619 | } |
| 2620 | |
Al Viro | 18bb1db | 2011-07-26 01:41:39 -0400 | [diff] [blame] | 2621 | int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2622 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2623 | int error = may_create(dir, dentry); |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 2624 | unsigned max_links = dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2625 | |
| 2626 | if (error) |
| 2627 | return error; |
| 2628 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2629 | if (!dir->i_op->mkdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2630 | return -EPERM; |
| 2631 | |
| 2632 | mode &= (S_IRWXUGO|S_ISVTX); |
| 2633 | error = security_inode_mkdir(dir, dentry, mode); |
| 2634 | if (error) |
| 2635 | return error; |
| 2636 | |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 2637 | if (max_links && dir->i_nlink >= max_links) |
| 2638 | return -EMLINK; |
| 2639 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2640 | error = dir->i_op->mkdir(dir, dentry, mode); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 2641 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 2642 | fsnotify_mkdir(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2643 | return error; |
| 2644 | } |
| 2645 | |
Al Viro | a218d0f | 2011-11-21 14:59:34 -0500 | [diff] [blame] | 2646 | SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2647 | { |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2648 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2649 | struct path path; |
| 2650 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2651 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2652 | dentry = user_path_create(dfd, pathname, &path, 1); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2653 | if (IS_ERR(dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2654 | return PTR_ERR(dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2655 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2656 | if (!IS_POSIXACL(path.dentry->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 2657 | mode &= ~current_umask(); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2658 | error = mnt_want_write(path.mnt); |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2659 | if (error) |
| 2660 | goto out_dput; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2661 | error = security_path_mkdir(&path, dentry, mode); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2662 | if (error) |
| 2663 | goto out_drop_write; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2664 | error = vfs_mkdir(path.dentry->d_inode, dentry, mode); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2665 | out_drop_write: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2666 | mnt_drop_write(path.mnt); |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2667 | out_dput: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2668 | dput(dentry); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2669 | mutex_unlock(&path.dentry->d_inode->i_mutex); |
| 2670 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2671 | return error; |
| 2672 | } |
| 2673 | |
Al Viro | a218d0f | 2011-11-21 14:59:34 -0500 | [diff] [blame] | 2674 | SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2675 | { |
| 2676 | return sys_mkdirat(AT_FDCWD, pathname, mode); |
| 2677 | } |
| 2678 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2679 | /* |
Sage Weil | a71905f | 2011-05-24 13:06:08 -0700 | [diff] [blame] | 2680 | * The dentry_unhash() helper will try to drop the dentry early: we |
J. Bruce Fields | c0d0259 | 2012-02-15 11:48:40 -0500 | [diff] [blame] | 2681 | * should have a usage count of 1 if we're the only user of this |
Sage Weil | a71905f | 2011-05-24 13:06:08 -0700 | [diff] [blame] | 2682 | * dentry, and if that is true (possibly after pruning the dcache), |
| 2683 | * then we drop the dentry now. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2684 | * |
| 2685 | * A low-level filesystem can, if it choses, legally |
| 2686 | * do a |
| 2687 | * |
| 2688 | * if (!d_unhashed(dentry)) |
| 2689 | * return -EBUSY; |
| 2690 | * |
| 2691 | * if it cannot handle the case of removing a directory |
| 2692 | * that is still in use by something else.. |
| 2693 | */ |
| 2694 | void dentry_unhash(struct dentry *dentry) |
| 2695 | { |
Vasily Averin | dc16842 | 2006-12-06 20:37:07 -0800 | [diff] [blame] | 2696 | shrink_dcache_parent(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2697 | spin_lock(&dentry->d_lock); |
Sage Weil | 64252c7 | 2011-05-24 13:06:05 -0700 | [diff] [blame] | 2698 | if (dentry->d_count == 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2699 | __d_drop(dentry); |
| 2700 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2701 | } |
| 2702 | |
| 2703 | int vfs_rmdir(struct inode *dir, struct dentry *dentry) |
| 2704 | { |
| 2705 | int error = may_delete(dir, dentry, 1); |
| 2706 | |
| 2707 | if (error) |
| 2708 | return error; |
| 2709 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2710 | if (!dir->i_op->rmdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2711 | return -EPERM; |
| 2712 | |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 2713 | dget(dentry); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2714 | mutex_lock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2715 | |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 2716 | error = -EBUSY; |
| 2717 | if (d_mountpoint(dentry)) |
| 2718 | goto out; |
| 2719 | |
| 2720 | error = security_inode_rmdir(dir, dentry); |
| 2721 | if (error) |
| 2722 | goto out; |
| 2723 | |
Sage Weil | 3cebde2 | 2011-05-29 21:20:59 -0700 | [diff] [blame] | 2724 | shrink_dcache_parent(dentry); |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 2725 | error = dir->i_op->rmdir(dir, dentry); |
| 2726 | if (error) |
| 2727 | goto out; |
| 2728 | |
| 2729 | dentry->d_inode->i_flags |= S_DEAD; |
| 2730 | dont_mount(dentry); |
| 2731 | |
| 2732 | out: |
| 2733 | mutex_unlock(&dentry->d_inode->i_mutex); |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 2734 | dput(dentry); |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 2735 | if (!error) |
| 2736 | d_delete(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2737 | return error; |
| 2738 | } |
| 2739 | |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2740 | static long do_rmdir(int dfd, const char __user *pathname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2741 | { |
| 2742 | int error = 0; |
| 2743 | char * name; |
| 2744 | struct dentry *dentry; |
| 2745 | struct nameidata nd; |
| 2746 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2747 | error = user_path_parent(dfd, pathname, &nd, &name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2748 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2749 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2750 | |
| 2751 | switch(nd.last_type) { |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2752 | case LAST_DOTDOT: |
| 2753 | error = -ENOTEMPTY; |
| 2754 | goto exit1; |
| 2755 | case LAST_DOT: |
| 2756 | error = -EINVAL; |
| 2757 | goto exit1; |
| 2758 | case LAST_ROOT: |
| 2759 | error = -EBUSY; |
| 2760 | goto exit1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2761 | } |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2762 | |
| 2763 | nd.flags &= ~LOOKUP_PARENT; |
| 2764 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2765 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 2766 | dentry = lookup_hash(&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2767 | error = PTR_ERR(dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2768 | if (IS_ERR(dentry)) |
| 2769 | goto exit2; |
Theodore Ts'o | e6bc45d | 2011-06-06 19:19:40 -0400 | [diff] [blame] | 2770 | if (!dentry->d_inode) { |
| 2771 | error = -ENOENT; |
| 2772 | goto exit3; |
| 2773 | } |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 2774 | error = mnt_want_write(nd.path.mnt); |
| 2775 | if (error) |
| 2776 | goto exit3; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2777 | error = security_path_rmdir(&nd.path, dentry); |
| 2778 | if (error) |
| 2779 | goto exit4; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2780 | error = vfs_rmdir(nd.path.dentry->d_inode, dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2781 | exit4: |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 2782 | mnt_drop_write(nd.path.mnt); |
| 2783 | exit3: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2784 | dput(dentry); |
| 2785 | exit2: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2786 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2787 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2788 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2789 | putname(name); |
| 2790 | return error; |
| 2791 | } |
| 2792 | |
Heiko Carstens | 3cdad42 | 2009-01-14 14:14:22 +0100 | [diff] [blame] | 2793 | SYSCALL_DEFINE1(rmdir, const char __user *, pathname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2794 | { |
| 2795 | return do_rmdir(AT_FDCWD, pathname); |
| 2796 | } |
| 2797 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2798 | int vfs_unlink(struct inode *dir, struct dentry *dentry) |
| 2799 | { |
| 2800 | int error = may_delete(dir, dentry, 0); |
| 2801 | |
| 2802 | if (error) |
| 2803 | return error; |
| 2804 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2805 | if (!dir->i_op->unlink) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2806 | return -EPERM; |
| 2807 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2808 | mutex_lock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2809 | if (d_mountpoint(dentry)) |
| 2810 | error = -EBUSY; |
| 2811 | else { |
| 2812 | error = security_inode_unlink(dir, dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 2813 | if (!error) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2814 | error = dir->i_op->unlink(dir, dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 2815 | if (!error) |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2816 | dont_mount(dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 2817 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2818 | } |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2819 | mutex_unlock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2820 | |
| 2821 | /* We don't d_delete() NFS sillyrenamed files--they still exist. */ |
| 2822 | if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { |
Jan Kara | ece9591 | 2008-02-06 01:37:13 -0800 | [diff] [blame] | 2823 | fsnotify_link_count(dentry->d_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2824 | d_delete(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2825 | } |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 2826 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2827 | return error; |
| 2828 | } |
| 2829 | |
| 2830 | /* |
| 2831 | * Make sure that the actual truncation of the file will occur outside its |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2832 | * directory's i_mutex. Truncate can take a long time if there is a lot of |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2833 | * writeout happening, and we don't want to prevent access to the directory |
| 2834 | * while waiting on the I/O. |
| 2835 | */ |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2836 | static long do_unlinkat(int dfd, const char __user *pathname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2837 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2838 | int error; |
| 2839 | char *name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2840 | struct dentry *dentry; |
| 2841 | struct nameidata nd; |
| 2842 | struct inode *inode = NULL; |
| 2843 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2844 | error = user_path_parent(dfd, pathname, &nd, &name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2845 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2846 | return error; |
| 2847 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2848 | error = -EISDIR; |
| 2849 | if (nd.last_type != LAST_NORM) |
| 2850 | goto exit1; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2851 | |
| 2852 | nd.flags &= ~LOOKUP_PARENT; |
| 2853 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2854 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 2855 | dentry = lookup_hash(&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2856 | error = PTR_ERR(dentry); |
| 2857 | if (!IS_ERR(dentry)) { |
| 2858 | /* Why not before? Because we want correct error value */ |
Török Edwin | 50338b8 | 2011-06-16 00:06:14 +0300 | [diff] [blame] | 2859 | if (nd.last.name[nd.last.len]) |
| 2860 | goto slashes; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2861 | inode = dentry->d_inode; |
Török Edwin | 50338b8 | 2011-06-16 00:06:14 +0300 | [diff] [blame] | 2862 | if (!inode) |
Theodore Ts'o | e6bc45d | 2011-06-06 19:19:40 -0400 | [diff] [blame] | 2863 | goto slashes; |
| 2864 | ihold(inode); |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 2865 | error = mnt_want_write(nd.path.mnt); |
| 2866 | if (error) |
| 2867 | goto exit2; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2868 | error = security_path_unlink(&nd.path, dentry); |
| 2869 | if (error) |
| 2870 | goto exit3; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2871 | error = vfs_unlink(nd.path.dentry->d_inode, dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2872 | exit3: |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 2873 | mnt_drop_write(nd.path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2874 | exit2: |
| 2875 | dput(dentry); |
| 2876 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2877 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2878 | if (inode) |
| 2879 | iput(inode); /* truncate the inode here */ |
| 2880 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2881 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2882 | putname(name); |
| 2883 | return error; |
| 2884 | |
| 2885 | slashes: |
| 2886 | error = !dentry->d_inode ? -ENOENT : |
| 2887 | S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; |
| 2888 | goto exit2; |
| 2889 | } |
| 2890 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 2891 | SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2892 | { |
| 2893 | if ((flag & ~AT_REMOVEDIR) != 0) |
| 2894 | return -EINVAL; |
| 2895 | |
| 2896 | if (flag & AT_REMOVEDIR) |
| 2897 | return do_rmdir(dfd, pathname); |
| 2898 | |
| 2899 | return do_unlinkat(dfd, pathname); |
| 2900 | } |
| 2901 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 2902 | SYSCALL_DEFINE1(unlink, const char __user *, pathname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2903 | { |
| 2904 | return do_unlinkat(AT_FDCWD, pathname); |
| 2905 | } |
| 2906 | |
Miklos Szeredi | db2e747 | 2008-06-24 16:50:16 +0200 | [diff] [blame] | 2907 | int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2908 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2909 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2910 | |
| 2911 | if (error) |
| 2912 | return error; |
| 2913 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2914 | if (!dir->i_op->symlink) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2915 | return -EPERM; |
| 2916 | |
| 2917 | error = security_inode_symlink(dir, dentry, oldname); |
| 2918 | if (error) |
| 2919 | return error; |
| 2920 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2921 | error = dir->i_op->symlink(dir, dentry, oldname); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 2922 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 2923 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2924 | return error; |
| 2925 | } |
| 2926 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 2927 | SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, |
| 2928 | int, newdfd, const char __user *, newname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2929 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2930 | int error; |
| 2931 | char *from; |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2932 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2933 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2934 | |
| 2935 | from = getname(oldname); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2936 | if (IS_ERR(from)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2937 | return PTR_ERR(from); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2938 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2939 | dentry = user_path_create(newdfd, newname, &path, 0); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2940 | error = PTR_ERR(dentry); |
| 2941 | if (IS_ERR(dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2942 | goto out_putname; |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2943 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2944 | error = mnt_want_write(path.mnt); |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 2945 | if (error) |
| 2946 | goto out_dput; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2947 | error = security_path_symlink(&path, dentry, from); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2948 | if (error) |
| 2949 | goto out_drop_write; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2950 | error = vfs_symlink(path.dentry->d_inode, dentry, from); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2951 | out_drop_write: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2952 | mnt_drop_write(path.mnt); |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 2953 | out_dput: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2954 | dput(dentry); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 2955 | mutex_unlock(&path.dentry->d_inode->i_mutex); |
| 2956 | path_put(&path); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2957 | out_putname: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2958 | putname(from); |
| 2959 | return error; |
| 2960 | } |
| 2961 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 2962 | SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2963 | { |
| 2964 | return sys_symlinkat(oldname, AT_FDCWD, newname); |
| 2965 | } |
| 2966 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2967 | int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) |
| 2968 | { |
| 2969 | struct inode *inode = old_dentry->d_inode; |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 2970 | unsigned max_links = dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2971 | int error; |
| 2972 | |
| 2973 | if (!inode) |
| 2974 | return -ENOENT; |
| 2975 | |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2976 | error = may_create(dir, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2977 | if (error) |
| 2978 | return error; |
| 2979 | |
| 2980 | if (dir->i_sb != inode->i_sb) |
| 2981 | return -EXDEV; |
| 2982 | |
| 2983 | /* |
| 2984 | * A link to an append-only or immutable file cannot be created. |
| 2985 | */ |
| 2986 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) |
| 2987 | return -EPERM; |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2988 | if (!dir->i_op->link) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2989 | return -EPERM; |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 2990 | if (S_ISDIR(inode->i_mode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2991 | return -EPERM; |
| 2992 | |
| 2993 | error = security_inode_link(old_dentry, dir, new_dentry); |
| 2994 | if (error) |
| 2995 | return error; |
| 2996 | |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 2997 | mutex_lock(&inode->i_mutex); |
Aneesh Kumar K.V | aae8a97 | 2011-01-29 18:43:27 +0530 | [diff] [blame] | 2998 | /* Make sure we don't allow creating hardlink to an unlinked file */ |
| 2999 | if (inode->i_nlink == 0) |
| 3000 | error = -ENOENT; |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3001 | else if (max_links && inode->i_nlink >= max_links) |
| 3002 | error = -EMLINK; |
Aneesh Kumar K.V | aae8a97 | 2011-01-29 18:43:27 +0530 | [diff] [blame] | 3003 | else |
| 3004 | error = dir->i_op->link(old_dentry, dir, new_dentry); |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 3005 | mutex_unlock(&inode->i_mutex); |
Stephen Smalley | e31e14e | 2005-09-09 13:01:45 -0700 | [diff] [blame] | 3006 | if (!error) |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 3007 | fsnotify_link(dir, inode, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3008 | return error; |
| 3009 | } |
| 3010 | |
| 3011 | /* |
| 3012 | * Hardlinks are often used in delicate situations. We avoid |
| 3013 | * security-related surprises by not following symlinks on the |
| 3014 | * newname. --KAB |
| 3015 | * |
| 3016 | * We don't follow them on the oldname either to be compatible |
| 3017 | * with linux 2.0, and to avoid hard-linking to directories |
| 3018 | * and other special files. --ADM |
| 3019 | */ |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3020 | SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, |
| 3021 | int, newdfd, const char __user *, newname, int, flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3022 | { |
| 3023 | struct dentry *new_dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3024 | struct path old_path, new_path; |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3025 | int how = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3026 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3027 | |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3028 | if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0) |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 3029 | return -EINVAL; |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3030 | /* |
| 3031 | * To use null names we require CAP_DAC_READ_SEARCH |
| 3032 | * This ensures that not everyone will be able to create |
| 3033 | * handlink using the passed filedescriptor. |
| 3034 | */ |
| 3035 | if (flags & AT_EMPTY_PATH) { |
| 3036 | if (!capable(CAP_DAC_READ_SEARCH)) |
| 3037 | return -ENOENT; |
| 3038 | how = LOOKUP_EMPTY; |
| 3039 | } |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 3040 | |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3041 | if (flags & AT_SYMLINK_FOLLOW) |
| 3042 | how |= LOOKUP_FOLLOW; |
| 3043 | |
| 3044 | error = user_path_at(olddfd, oldname, how, &old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3045 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3046 | return error; |
| 3047 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3048 | new_dentry = user_path_create(newdfd, newname, &new_path, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3049 | error = PTR_ERR(new_dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3050 | if (IS_ERR(new_dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3051 | goto out; |
| 3052 | |
| 3053 | error = -EXDEV; |
| 3054 | if (old_path.mnt != new_path.mnt) |
| 3055 | goto out_dput; |
| 3056 | error = mnt_want_write(new_path.mnt); |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 3057 | if (error) |
| 3058 | goto out_dput; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3059 | error = security_path_link(old_path.dentry, &new_path, new_dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3060 | if (error) |
| 3061 | goto out_drop_write; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3062 | error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3063 | out_drop_write: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3064 | mnt_drop_write(new_path.mnt); |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 3065 | out_dput: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3066 | dput(new_dentry); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3067 | mutex_unlock(&new_path.dentry->d_inode->i_mutex); |
| 3068 | path_put(&new_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3069 | out: |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 3070 | path_put(&old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3071 | |
| 3072 | return error; |
| 3073 | } |
| 3074 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 3075 | SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3076 | { |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 3077 | return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3078 | } |
| 3079 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3080 | /* |
| 3081 | * The worst of all namespace operations - renaming directory. "Perverted" |
| 3082 | * doesn't even start to describe it. Somebody in UCB had a heck of a trip... |
| 3083 | * Problems: |
| 3084 | * a) we can get into loop creation. Check is done in is_subdir(). |
| 3085 | * b) race potential - two innocent renames can create a loop together. |
| 3086 | * That's where 4.4 screws up. Current fix: serialization on |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 3087 | * sb->s_vfs_rename_mutex. We might be more accurate, but that's another |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3088 | * story. |
| 3089 | * c) we have to lock _three_ objects - parents and victim (if it exists). |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3090 | * And that - after we got ->i_mutex on parents (until then we don't know |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3091 | * whether the target exists). Solution: try to be smart with locking |
| 3092 | * order for inodes. We rely on the fact that tree topology may change |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 3093 | * only under ->s_vfs_rename_mutex _and_ that parent of the object we |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3094 | * move will be locked. Thus we can rank directories by the tree |
| 3095 | * (ancestors first) and rank all non-directories after them. |
| 3096 | * That works since everybody except rename does "lock parent, lookup, |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 3097 | * lock child" and rename is under ->s_vfs_rename_mutex. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3098 | * HOWEVER, it relies on the assumption that any object with ->lookup() |
| 3099 | * has no more than 1 dentry. If "hybrid" objects will ever appear, |
| 3100 | * we'd better make sure that there's no link(2) for them. |
Sage Weil | e4eaac0 | 2011-05-24 13:06:07 -0700 | [diff] [blame] | 3101 | * d) conversion from fhandle to dentry may come in the wrong moment - when |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3102 | * we are removing the target. Solution: we will have to grab ->i_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3103 | * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on |
Adam Buchbinder | c41b20e | 2009-12-11 16:35:39 -0500 | [diff] [blame] | 3104 | * ->i_mutex on parents, which works but leads to some truly excessive |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3105 | * locking]. |
| 3106 | */ |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 3107 | static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, |
| 3108 | struct inode *new_dir, struct dentry *new_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3109 | { |
| 3110 | int error = 0; |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3111 | struct inode *target = new_dentry->d_inode; |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3112 | unsigned max_links = new_dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3113 | |
| 3114 | /* |
| 3115 | * If we are going to change the parent - check write permissions, |
| 3116 | * we'll need to flip '..'. |
| 3117 | */ |
| 3118 | if (new_dir != old_dir) { |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 3119 | error = inode_permission(old_dentry->d_inode, MAY_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3120 | if (error) |
| 3121 | return error; |
| 3122 | } |
| 3123 | |
| 3124 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); |
| 3125 | if (error) |
| 3126 | return error; |
| 3127 | |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 3128 | dget(new_dentry); |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 3129 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3130 | mutex_lock(&target->i_mutex); |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3131 | |
| 3132 | error = -EBUSY; |
| 3133 | if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry)) |
| 3134 | goto out; |
| 3135 | |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3136 | error = -EMLINK; |
| 3137 | if (max_links && !target && new_dir != old_dir && |
| 3138 | new_dir->i_nlink >= max_links) |
| 3139 | goto out; |
| 3140 | |
Sage Weil | 3cebde2 | 2011-05-29 21:20:59 -0700 | [diff] [blame] | 3141 | if (target) |
| 3142 | shrink_dcache_parent(new_dentry); |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3143 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); |
| 3144 | if (error) |
| 3145 | goto out; |
| 3146 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3147 | if (target) { |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3148 | target->i_flags |= S_DEAD; |
| 3149 | dont_mount(new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3150 | } |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3151 | out: |
| 3152 | if (target) |
| 3153 | mutex_unlock(&target->i_mutex); |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 3154 | dput(new_dentry); |
Stephen Smalley | e31e14e | 2005-09-09 13:01:45 -0700 | [diff] [blame] | 3155 | if (!error) |
Mark Fasheh | 349457c | 2006-09-08 14:22:21 -0700 | [diff] [blame] | 3156 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
| 3157 | d_move(old_dentry,new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3158 | return error; |
| 3159 | } |
| 3160 | |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 3161 | static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, |
| 3162 | struct inode *new_dir, struct dentry *new_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3163 | { |
Sage Weil | 51892bb | 2011-05-24 13:06:13 -0700 | [diff] [blame] | 3164 | struct inode *target = new_dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3165 | int error; |
| 3166 | |
| 3167 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); |
| 3168 | if (error) |
| 3169 | return error; |
| 3170 | |
| 3171 | dget(new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3172 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3173 | mutex_lock(&target->i_mutex); |
Sage Weil | 51892bb | 2011-05-24 13:06:13 -0700 | [diff] [blame] | 3174 | |
| 3175 | error = -EBUSY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3176 | if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) |
Sage Weil | 51892bb | 2011-05-24 13:06:13 -0700 | [diff] [blame] | 3177 | goto out; |
| 3178 | |
| 3179 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); |
| 3180 | if (error) |
| 3181 | goto out; |
| 3182 | |
| 3183 | if (target) |
| 3184 | dont_mount(new_dentry); |
| 3185 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
| 3186 | d_move(old_dentry, new_dentry); |
| 3187 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3188 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3189 | mutex_unlock(&target->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3190 | dput(new_dentry); |
| 3191 | return error; |
| 3192 | } |
| 3193 | |
| 3194 | int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, |
| 3195 | struct inode *new_dir, struct dentry *new_dentry) |
| 3196 | { |
| 3197 | int error; |
| 3198 | int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); |
Eric Paris | 59b0df2 | 2010-02-08 12:53:52 -0500 | [diff] [blame] | 3199 | const unsigned char *old_name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3200 | |
| 3201 | if (old_dentry->d_inode == new_dentry->d_inode) |
| 3202 | return 0; |
| 3203 | |
| 3204 | error = may_delete(old_dir, old_dentry, is_dir); |
| 3205 | if (error) |
| 3206 | return error; |
| 3207 | |
| 3208 | if (!new_dentry->d_inode) |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3209 | error = may_create(new_dir, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3210 | else |
| 3211 | error = may_delete(new_dir, new_dentry, is_dir); |
| 3212 | if (error) |
| 3213 | return error; |
| 3214 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3215 | if (!old_dir->i_op->rename) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3216 | return -EPERM; |
| 3217 | |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 3218 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); |
| 3219 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3220 | if (is_dir) |
| 3221 | error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); |
| 3222 | else |
| 3223 | error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); |
Al Viro | 123df29 | 2009-12-25 04:57:57 -0500 | [diff] [blame] | 3224 | if (!error) |
| 3225 | fsnotify_move(old_dir, new_dir, old_name, is_dir, |
Al Viro | 5a190ae | 2007-06-07 12:19:32 -0400 | [diff] [blame] | 3226 | new_dentry->d_inode, old_dentry); |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 3227 | fsnotify_oldname_free(old_name); |
| 3228 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3229 | return error; |
| 3230 | } |
| 3231 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3232 | SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, |
| 3233 | int, newdfd, const char __user *, newname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3234 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3235 | struct dentry *old_dir, *new_dir; |
| 3236 | struct dentry *old_dentry, *new_dentry; |
| 3237 | struct dentry *trap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3238 | struct nameidata oldnd, newnd; |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3239 | char *from; |
| 3240 | char *to; |
| 3241 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3242 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3243 | error = user_path_parent(olddfd, oldname, &oldnd, &from); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3244 | if (error) |
| 3245 | goto exit; |
| 3246 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3247 | error = user_path_parent(newdfd, newname, &newnd, &to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3248 | if (error) |
| 3249 | goto exit1; |
| 3250 | |
| 3251 | error = -EXDEV; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3252 | if (oldnd.path.mnt != newnd.path.mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3253 | goto exit2; |
| 3254 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3255 | old_dir = oldnd.path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3256 | error = -EBUSY; |
| 3257 | if (oldnd.last_type != LAST_NORM) |
| 3258 | goto exit2; |
| 3259 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3260 | new_dir = newnd.path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3261 | if (newnd.last_type != LAST_NORM) |
| 3262 | goto exit2; |
| 3263 | |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3264 | oldnd.flags &= ~LOOKUP_PARENT; |
| 3265 | newnd.flags &= ~LOOKUP_PARENT; |
OGAWA Hirofumi | 4e9ed2f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3266 | newnd.flags |= LOOKUP_RENAME_TARGET; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3267 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3268 | trap = lock_rename(new_dir, old_dir); |
| 3269 | |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 3270 | old_dentry = lookup_hash(&oldnd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3271 | error = PTR_ERR(old_dentry); |
| 3272 | if (IS_ERR(old_dentry)) |
| 3273 | goto exit3; |
| 3274 | /* source must exist */ |
| 3275 | error = -ENOENT; |
| 3276 | if (!old_dentry->d_inode) |
| 3277 | goto exit4; |
| 3278 | /* unless the source is a directory trailing slashes give -ENOTDIR */ |
| 3279 | if (!S_ISDIR(old_dentry->d_inode->i_mode)) { |
| 3280 | error = -ENOTDIR; |
| 3281 | if (oldnd.last.name[oldnd.last.len]) |
| 3282 | goto exit4; |
| 3283 | if (newnd.last.name[newnd.last.len]) |
| 3284 | goto exit4; |
| 3285 | } |
| 3286 | /* source should not be ancestor of target */ |
| 3287 | error = -EINVAL; |
| 3288 | if (old_dentry == trap) |
| 3289 | goto exit4; |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 3290 | new_dentry = lookup_hash(&newnd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3291 | error = PTR_ERR(new_dentry); |
| 3292 | if (IS_ERR(new_dentry)) |
| 3293 | goto exit4; |
| 3294 | /* target should not be an ancestor of source */ |
| 3295 | error = -ENOTEMPTY; |
| 3296 | if (new_dentry == trap) |
| 3297 | goto exit5; |
| 3298 | |
Dave Hansen | 9079b1e | 2008-02-15 14:37:49 -0800 | [diff] [blame] | 3299 | error = mnt_want_write(oldnd.path.mnt); |
| 3300 | if (error) |
| 3301 | goto exit5; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3302 | error = security_path_rename(&oldnd.path, old_dentry, |
| 3303 | &newnd.path, new_dentry); |
| 3304 | if (error) |
| 3305 | goto exit6; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3306 | error = vfs_rename(old_dir->d_inode, old_dentry, |
| 3307 | new_dir->d_inode, new_dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3308 | exit6: |
Dave Hansen | 9079b1e | 2008-02-15 14:37:49 -0800 | [diff] [blame] | 3309 | mnt_drop_write(oldnd.path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3310 | exit5: |
| 3311 | dput(new_dentry); |
| 3312 | exit4: |
| 3313 | dput(old_dentry); |
| 3314 | exit3: |
| 3315 | unlock_rename(new_dir, old_dir); |
| 3316 | exit2: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 3317 | path_put(&newnd.path); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3318 | putname(to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3319 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 3320 | path_put(&oldnd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3321 | putname(from); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3322 | exit: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3323 | return error; |
| 3324 | } |
| 3325 | |
Heiko Carstens | a26eab2 | 2009-01-14 14:14:17 +0100 | [diff] [blame] | 3326 | SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3327 | { |
| 3328 | return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); |
| 3329 | } |
| 3330 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3331 | int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) |
| 3332 | { |
| 3333 | int len; |
| 3334 | |
| 3335 | len = PTR_ERR(link); |
| 3336 | if (IS_ERR(link)) |
| 3337 | goto out; |
| 3338 | |
| 3339 | len = strlen(link); |
| 3340 | if (len > (unsigned) buflen) |
| 3341 | len = buflen; |
| 3342 | if (copy_to_user(buffer, link, len)) |
| 3343 | len = -EFAULT; |
| 3344 | out: |
| 3345 | return len; |
| 3346 | } |
| 3347 | |
| 3348 | /* |
| 3349 | * A helper for ->readlink(). This should be used *ONLY* for symlinks that |
| 3350 | * have ->follow_link() touching nd only in nd_set_link(). Using (or not |
| 3351 | * using) it for any given inode is up to filesystem. |
| 3352 | */ |
| 3353 | int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 3354 | { |
| 3355 | struct nameidata nd; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 3356 | void *cookie; |
Marcin Slusarz | 694a176 | 2008-06-09 16:40:37 -0700 | [diff] [blame] | 3357 | int res; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 3358 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3359 | nd.depth = 0; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 3360 | cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); |
Marcin Slusarz | 694a176 | 2008-06-09 16:40:37 -0700 | [diff] [blame] | 3361 | if (IS_ERR(cookie)) |
| 3362 | return PTR_ERR(cookie); |
| 3363 | |
| 3364 | res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); |
| 3365 | if (dentry->d_inode->i_op->put_link) |
| 3366 | dentry->d_inode->i_op->put_link(dentry, &nd, cookie); |
| 3367 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3368 | } |
| 3369 | |
| 3370 | int vfs_follow_link(struct nameidata *nd, const char *link) |
| 3371 | { |
| 3372 | return __vfs_follow_link(nd, link); |
| 3373 | } |
| 3374 | |
| 3375 | /* get the link contents into pagecache */ |
| 3376 | static char *page_getlink(struct dentry * dentry, struct page **ppage) |
| 3377 | { |
Duane Griffin | ebd09ab | 2008-12-19 20:47:12 +0000 | [diff] [blame] | 3378 | char *kaddr; |
| 3379 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3380 | struct address_space *mapping = dentry->d_inode->i_mapping; |
Pekka Enberg | 090d2b1 | 2006-06-23 02:05:08 -0700 | [diff] [blame] | 3381 | page = read_mapping_page(mapping, 0, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3382 | if (IS_ERR(page)) |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 3383 | return (char*)page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3384 | *ppage = page; |
Duane Griffin | ebd09ab | 2008-12-19 20:47:12 +0000 | [diff] [blame] | 3385 | kaddr = kmap(page); |
| 3386 | nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); |
| 3387 | return kaddr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3388 | } |
| 3389 | |
| 3390 | int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 3391 | { |
| 3392 | struct page *page = NULL; |
| 3393 | char *s = page_getlink(dentry, &page); |
| 3394 | int res = vfs_readlink(dentry,buffer,buflen,s); |
| 3395 | if (page) { |
| 3396 | kunmap(page); |
| 3397 | page_cache_release(page); |
| 3398 | } |
| 3399 | return res; |
| 3400 | } |
| 3401 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 3402 | void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3403 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 3404 | struct page *page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3405 | nd_set_link(nd, page_getlink(dentry, &page)); |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 3406 | return page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3407 | } |
| 3408 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 3409 | void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3410 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 3411 | struct page *page = cookie; |
| 3412 | |
| 3413 | if (page) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3414 | kunmap(page); |
| 3415 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3416 | } |
| 3417 | } |
| 3418 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 3419 | /* |
| 3420 | * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS |
| 3421 | */ |
| 3422 | int __page_symlink(struct inode *inode, const char *symname, int len, int nofs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3423 | { |
| 3424 | struct address_space *mapping = inode->i_mapping; |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 3425 | struct page *page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 3426 | void *fsdata; |
Dmitriy Monakhov | beb497a | 2007-02-16 01:27:18 -0800 | [diff] [blame] | 3427 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3428 | char *kaddr; |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 3429 | unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; |
| 3430 | if (nofs) |
| 3431 | flags |= AOP_FLAG_NOFS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3432 | |
NeilBrown | 7e53cac | 2006-03-25 03:07:57 -0800 | [diff] [blame] | 3433 | retry: |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 3434 | err = pagecache_write_begin(NULL, mapping, 0, len-1, |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 3435 | flags, &page, &fsdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3436 | if (err) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 3437 | goto fail; |
| 3438 | |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 3439 | kaddr = kmap_atomic(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3440 | memcpy(kaddr, symname, len-1); |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 3441 | kunmap_atomic(kaddr); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 3442 | |
| 3443 | err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, |
| 3444 | page, fsdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3445 | if (err < 0) |
| 3446 | goto fail; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 3447 | if (err < len-1) |
| 3448 | goto retry; |
| 3449 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3450 | mark_inode_dirty(inode); |
| 3451 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3452 | fail: |
| 3453 | return err; |
| 3454 | } |
| 3455 | |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 3456 | int page_symlink(struct inode *inode, const char *symname, int len) |
| 3457 | { |
| 3458 | return __page_symlink(inode, symname, len, |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 3459 | !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS)); |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 3460 | } |
| 3461 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 3462 | const struct inode_operations page_symlink_inode_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3463 | .readlink = generic_readlink, |
| 3464 | .follow_link = page_follow_link_light, |
| 3465 | .put_link = page_put_link, |
| 3466 | }; |
| 3467 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 3468 | EXPORT_SYMBOL(user_path_at); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 3469 | EXPORT_SYMBOL(follow_down_one); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3470 | EXPORT_SYMBOL(follow_down); |
| 3471 | EXPORT_SYMBOL(follow_up); |
| 3472 | EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ |
| 3473 | EXPORT_SYMBOL(getname); |
| 3474 | EXPORT_SYMBOL(lock_rename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3475 | EXPORT_SYMBOL(lookup_one_len); |
| 3476 | EXPORT_SYMBOL(page_follow_link_light); |
| 3477 | EXPORT_SYMBOL(page_put_link); |
| 3478 | EXPORT_SYMBOL(page_readlink); |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 3479 | EXPORT_SYMBOL(__page_symlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3480 | EXPORT_SYMBOL(page_symlink); |
| 3481 | EXPORT_SYMBOL(page_symlink_inode_operations); |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 3482 | EXPORT_SYMBOL(kern_path); |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 3483 | EXPORT_SYMBOL(vfs_path_lookup); |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 3484 | EXPORT_SYMBOL(inode_permission); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3485 | EXPORT_SYMBOL(unlock_rename); |
| 3486 | EXPORT_SYMBOL(vfs_create); |
| 3487 | EXPORT_SYMBOL(vfs_follow_link); |
| 3488 | EXPORT_SYMBOL(vfs_link); |
| 3489 | EXPORT_SYMBOL(vfs_mkdir); |
| 3490 | EXPORT_SYMBOL(vfs_mknod); |
| 3491 | EXPORT_SYMBOL(generic_permission); |
| 3492 | EXPORT_SYMBOL(vfs_readlink); |
| 3493 | EXPORT_SYMBOL(vfs_rename); |
| 3494 | EXPORT_SYMBOL(vfs_rmdir); |
| 3495 | EXPORT_SYMBOL(vfs_symlink); |
| 3496 | EXPORT_SYMBOL(vfs_unlink); |
| 3497 | EXPORT_SYMBOL(dentry_unhash); |
| 3498 | EXPORT_SYMBOL(generic_readlink); |