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> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/slab.h> |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/namei.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | #include <linux/pagemap.h> |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 23 | #include <linux/fsnotify.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | #include <linux/personality.h> |
| 25 | #include <linux/security.h> |
Mimi Zohar | 6146f0d | 2009-02-04 09:06:57 -0500 | [diff] [blame] | 26 | #include <linux/ima.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | #include <linux/syscalls.h> |
| 28 | #include <linux/mount.h> |
| 29 | #include <linux/audit.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 30 | #include <linux/capability.h> |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 31 | #include <linux/file.h> |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 32 | #include <linux/fcntl.h> |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 33 | #include <linux/device_cgroup.h> |
Al Viro | 5ad4e53 | 2009-03-29 19:50:06 -0400 | [diff] [blame] | 34 | #include <linux/fs_struct.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <asm/uaccess.h> |
| 36 | |
Eric Paris | e81e3f4 | 2009-12-04 15:47:36 -0500 | [diff] [blame] | 37 | #include "internal.h" |
| 38 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | /* [Feb-1997 T. Schoebel-Theuer] |
| 40 | * Fundamental changes in the pathname lookup mechanisms (namei) |
| 41 | * were necessary because of omirr. The reason is that omirr needs |
| 42 | * to know the _real_ pathname, not the user-supplied one, in case |
| 43 | * of symlinks (and also when transname replacements occur). |
| 44 | * |
| 45 | * The new code replaces the old recursive symlink resolution with |
| 46 | * an iterative one (in case of non-nested symlink chains). It does |
| 47 | * this with calls to <fs>_follow_link(). |
| 48 | * As a side effect, dir_namei(), _namei() and follow_link() are now |
| 49 | * replaced with a single function lookup_dentry() that can handle all |
| 50 | * the special cases of the former code. |
| 51 | * |
| 52 | * With the new dcache, the pathname is stored at each inode, at least as |
| 53 | * long as the refcount of the inode is positive. As a side effect, the |
| 54 | * size of the dcache depends on the inode cache and thus is dynamic. |
| 55 | * |
| 56 | * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink |
| 57 | * resolution to correspond with current state of the code. |
| 58 | * |
| 59 | * Note that the symlink resolution is not *completely* iterative. |
| 60 | * There is still a significant amount of tail- and mid- recursion in |
| 61 | * the algorithm. Also, note that <fs>_readlink() is not used in |
| 62 | * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() |
| 63 | * may return different results than <fs>_follow_link(). Many virtual |
| 64 | * filesystems (including /proc) exhibit this behavior. |
| 65 | */ |
| 66 | |
| 67 | /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: |
| 68 | * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL |
| 69 | * and the name already exists in form of a symlink, try to create the new |
| 70 | * name indicated by the symlink. The old code always complained that the |
| 71 | * name already exists, due to not following the symlink even if its target |
| 72 | * is nonexistent. The new semantics affects also mknod() and link() when |
| 73 | * the name is a symlink pointing to a non-existant name. |
| 74 | * |
| 75 | * I don't know which semantics is the right one, since I have no access |
| 76 | * to standards. But I found by trial that HP-UX 9.0 has the full "new" |
| 77 | * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the |
| 78 | * "old" one. Personally, I think the new semantics is much more logical. |
| 79 | * Note that "ln old new" where "new" is a symlink pointing to a non-existing |
| 80 | * file does succeed in both HP-UX and SunOs, but not in Solaris |
| 81 | * and in the old Linux semantics. |
| 82 | */ |
| 83 | |
| 84 | /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink |
| 85 | * semantics. See the comments in "open_namei" and "do_link" below. |
| 86 | * |
| 87 | * [10-Sep-98 Alan Modra] Another symlink change. |
| 88 | */ |
| 89 | |
| 90 | /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: |
| 91 | * inside the path - always follow. |
| 92 | * in the last component in creation/removal/renaming - never follow. |
| 93 | * if LOOKUP_FOLLOW passed - follow. |
| 94 | * if the pathname has trailing slashes - follow. |
| 95 | * otherwise - don't follow. |
| 96 | * (applied in that order). |
| 97 | * |
| 98 | * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT |
| 99 | * restored for 2.4. This is the last surviving part of old 4.2BSD bug. |
| 100 | * During the 2.4 we need to fix the userland stuff depending on it - |
| 101 | * hopefully we will be able to get rid of that wart in 2.5. So far only |
| 102 | * XEmacs seems to be relying on it... |
| 103 | */ |
| 104 | /* |
| 105 | * [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] | 106 | * 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] | 107 | * any extra contention... |
| 108 | */ |
| 109 | |
| 110 | /* In order to reduce some races, while at the same time doing additional |
| 111 | * checking and hopefully speeding things up, we copy filenames to the |
| 112 | * kernel data space before using them.. |
| 113 | * |
| 114 | * POSIX.1 2.4: an empty pathname is invalid (ENOENT). |
| 115 | * PATH_MAX includes the nul terminator --RR. |
| 116 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 117 | static int do_getname(const char __user *filename, char *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | { |
| 119 | int retval; |
| 120 | unsigned long len = PATH_MAX; |
| 121 | |
| 122 | if (!segment_eq(get_fs(), KERNEL_DS)) { |
| 123 | if ((unsigned long) filename >= TASK_SIZE) |
| 124 | return -EFAULT; |
| 125 | if (TASK_SIZE - (unsigned long) filename < PATH_MAX) |
| 126 | len = TASK_SIZE - (unsigned long) filename; |
| 127 | } |
| 128 | |
| 129 | retval = strncpy_from_user(page, filename, len); |
| 130 | if (retval > 0) { |
| 131 | if (retval < len) |
| 132 | return 0; |
| 133 | return -ENAMETOOLONG; |
| 134 | } else if (!retval) |
| 135 | retval = -ENOENT; |
| 136 | return retval; |
| 137 | } |
| 138 | |
| 139 | char * getname(const char __user * filename) |
| 140 | { |
| 141 | char *tmp, *result; |
| 142 | |
| 143 | result = ERR_PTR(-ENOMEM); |
| 144 | tmp = __getname(); |
| 145 | if (tmp) { |
| 146 | int retval = do_getname(filename, tmp); |
| 147 | |
| 148 | result = tmp; |
| 149 | if (retval < 0) { |
| 150 | __putname(tmp); |
| 151 | result = ERR_PTR(retval); |
| 152 | } |
| 153 | } |
| 154 | audit_getname(result); |
| 155 | return result; |
| 156 | } |
| 157 | |
| 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 | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 169 | /* |
| 170 | * This does basic POSIX ACL permission checking |
| 171 | */ |
| 172 | static int acl_permission_check(struct inode *inode, int mask, |
| 173 | int (*check_acl)(struct inode *inode, int mask)) |
| 174 | { |
| 175 | umode_t mode = inode->i_mode; |
| 176 | |
| 177 | mask &= MAY_READ | MAY_WRITE | MAY_EXEC; |
| 178 | |
| 179 | if (current_fsuid() == inode->i_uid) |
| 180 | mode >>= 6; |
| 181 | else { |
| 182 | if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) { |
| 183 | int error = check_acl(inode, mask); |
| 184 | if (error != -EAGAIN) |
| 185 | return error; |
| 186 | } |
| 187 | |
| 188 | if (in_group_p(inode->i_gid)) |
| 189 | mode >>= 3; |
| 190 | } |
| 191 | |
| 192 | /* |
| 193 | * If the DACs are ok we don't need any capability check. |
| 194 | */ |
| 195 | if ((mask & ~mode) == 0) |
| 196 | return 0; |
| 197 | return -EACCES; |
| 198 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | |
| 200 | /** |
| 201 | * generic_permission - check for access rights on a Posix-like filesystem |
| 202 | * @inode: inode to check access rights for |
| 203 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
| 204 | * @check_acl: optional callback to check for Posix ACLs |
| 205 | * |
| 206 | * Used to check for read/write/execute permissions on a file. |
| 207 | * We use "fsuid" for this, letting us set arbitrary permissions |
| 208 | * for filesystem access without changing the "normal" uids which |
| 209 | * are used for other things.. |
| 210 | */ |
| 211 | int generic_permission(struct inode *inode, int mask, |
| 212 | int (*check_acl)(struct inode *inode, int mask)) |
| 213 | { |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 214 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | |
| 216 | /* |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 217 | * Do the basic POSIX ACL permission checks. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | */ |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 219 | ret = acl_permission_check(inode, mask, check_acl); |
| 220 | if (ret != -EACCES) |
| 221 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 222 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | /* |
| 224 | * Read/write DACs are always overridable. |
| 225 | * Executable DACs are overridable if at least one exec bit is set. |
| 226 | */ |
Miklos Szeredi | f696a36 | 2008-07-31 13:41:58 +0200 | [diff] [blame] | 227 | if (!(mask & MAY_EXEC) || execute_ok(inode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | if (capable(CAP_DAC_OVERRIDE)) |
| 229 | return 0; |
| 230 | |
| 231 | /* |
| 232 | * Searching includes executable on directories, else just read. |
| 233 | */ |
Serge E. Hallyn | 7ea6600 | 2009-12-29 14:50:19 -0600 | [diff] [blame] | 234 | mask &= MAY_READ | MAY_WRITE | MAY_EXEC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) |
| 236 | if (capable(CAP_DAC_READ_SEARCH)) |
| 237 | return 0; |
| 238 | |
| 239 | return -EACCES; |
| 240 | } |
| 241 | |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 242 | /** |
| 243 | * inode_permission - check for access rights to a given inode |
| 244 | * @inode: inode to check permission on |
| 245 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
| 246 | * |
| 247 | * Used to check for read/write/execute permissions on an inode. |
| 248 | * We use "fsuid" for this, letting us set arbitrary permissions |
| 249 | * for filesystem access without changing the "normal" uids which |
| 250 | * are used for other things. |
| 251 | */ |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 252 | int inode_permission(struct inode *inode, int mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | { |
Al Viro | e6305c4 | 2008-07-15 21:03:57 -0400 | [diff] [blame] | 254 | int retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | |
| 256 | if (mask & MAY_WRITE) { |
Miklos Szeredi | 22590e4 | 2007-10-16 23:27:08 -0700 | [diff] [blame] | 257 | umode_t mode = inode->i_mode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | |
| 259 | /* |
| 260 | * Nobody gets write access to a read-only fs. |
| 261 | */ |
| 262 | if (IS_RDONLY(inode) && |
| 263 | (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) |
| 264 | return -EROFS; |
| 265 | |
| 266 | /* |
| 267 | * Nobody gets write access to an immutable file. |
| 268 | */ |
| 269 | if (IS_IMMUTABLE(inode)) |
| 270 | return -EACCES; |
| 271 | } |
| 272 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 273 | if (inode->i_op->permission) |
Al Viro | b77b064 | 2008-07-17 09:37:02 -0400 | [diff] [blame] | 274 | retval = inode->i_op->permission(inode, mask); |
Miklos Szeredi | f696a36 | 2008-07-31 13:41:58 +0200 | [diff] [blame] | 275 | else |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 276 | retval = generic_permission(inode, mask, inode->i_op->check_acl); |
Miklos Szeredi | f696a36 | 2008-07-31 13:41:58 +0200 | [diff] [blame] | 277 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | if (retval) |
| 279 | return retval; |
| 280 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 281 | retval = devcgroup_inode_permission(inode, mask); |
| 282 | if (retval) |
| 283 | return retval; |
| 284 | |
Eric Paris | d09ca73 | 2010-07-23 11:43:57 -0400 | [diff] [blame] | 285 | return security_inode_permission(inode, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | } |
| 287 | |
Christoph Hellwig | e4543ed | 2005-11-08 21:35:04 -0800 | [diff] [blame] | 288 | /** |
Christoph Hellwig | 8c744fb | 2005-11-08 21:35:04 -0800 | [diff] [blame] | 289 | * file_permission - check for additional access rights to a given file |
| 290 | * @file: file to check access rights for |
| 291 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
| 292 | * |
| 293 | * Used to check for read/write/execute permissions on an already opened |
| 294 | * file. |
| 295 | * |
| 296 | * Note: |
| 297 | * Do not use this function in new code. All access checks should |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 298 | * be done using inode_permission(). |
Christoph Hellwig | 8c744fb | 2005-11-08 21:35:04 -0800 | [diff] [blame] | 299 | */ |
| 300 | int file_permission(struct file *file, int mask) |
| 301 | { |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 302 | return inode_permission(file->f_path.dentry->d_inode, mask); |
Christoph Hellwig | 8c744fb | 2005-11-08 21:35:04 -0800 | [diff] [blame] | 303 | } |
| 304 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | /* |
| 306 | * get_write_access() gets write permission for a file. |
| 307 | * put_write_access() releases this write permission. |
| 308 | * This is used for regular files. |
| 309 | * We cannot support write (and maybe mmap read-write shared) accesses and |
| 310 | * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode |
| 311 | * can have the following values: |
| 312 | * 0: no writers, no VM_DENYWRITE mappings |
| 313 | * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist |
| 314 | * > 0: (i_writecount) users are writing to the file. |
| 315 | * |
| 316 | * Normally we operate on that counter with atomic_{inc,dec} and it's safe |
| 317 | * except for the cases where we don't hold i_writecount yet. Then we need to |
| 318 | * use {get,deny}_write_access() - these functions check the sign and refuse |
| 319 | * to do the change if sign is wrong. Exclusion between them is provided by |
| 320 | * the inode->i_lock spinlock. |
| 321 | */ |
| 322 | |
| 323 | int get_write_access(struct inode * inode) |
| 324 | { |
| 325 | spin_lock(&inode->i_lock); |
| 326 | if (atomic_read(&inode->i_writecount) < 0) { |
| 327 | spin_unlock(&inode->i_lock); |
| 328 | return -ETXTBSY; |
| 329 | } |
| 330 | atomic_inc(&inode->i_writecount); |
| 331 | spin_unlock(&inode->i_lock); |
| 332 | |
| 333 | return 0; |
| 334 | } |
| 335 | |
| 336 | int deny_write_access(struct file * file) |
| 337 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 338 | struct inode *inode = file->f_path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 339 | |
| 340 | spin_lock(&inode->i_lock); |
| 341 | if (atomic_read(&inode->i_writecount) > 0) { |
| 342 | spin_unlock(&inode->i_lock); |
| 343 | return -ETXTBSY; |
| 344 | } |
| 345 | atomic_dec(&inode->i_writecount); |
| 346 | spin_unlock(&inode->i_lock); |
| 347 | |
| 348 | return 0; |
| 349 | } |
| 350 | |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 351 | /** |
Jan Blunck | 5dd784d | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 352 | * path_get - get a reference to a path |
| 353 | * @path: path to get the reference to |
| 354 | * |
| 355 | * Given a path increment the reference count to the dentry and the vfsmount. |
| 356 | */ |
| 357 | void path_get(struct path *path) |
| 358 | { |
| 359 | mntget(path->mnt); |
| 360 | dget(path->dentry); |
| 361 | } |
| 362 | EXPORT_SYMBOL(path_get); |
| 363 | |
| 364 | /** |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 365 | * path_put - put a reference to a path |
| 366 | * @path: path to put the reference to |
| 367 | * |
| 368 | * Given a path decrement the reference count to the dentry and the vfsmount. |
| 369 | */ |
| 370 | void path_put(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | { |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 372 | dput(path->dentry); |
| 373 | mntput(path->mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 374 | } |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 375 | EXPORT_SYMBOL(path_put); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 376 | |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 377 | /** |
| 378 | * release_open_intent - free up open intent resources |
| 379 | * @nd: pointer to nameidata |
| 380 | */ |
| 381 | void release_open_intent(struct nameidata *nd) |
| 382 | { |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 383 | if (nd->intent.open.file->f_path.dentry == NULL) |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 384 | put_filp(nd->intent.open.file); |
| 385 | else |
| 386 | fput(nd->intent.open.file); |
| 387 | } |
| 388 | |
Ian Kent | bcdc5e0 | 2006-09-27 01:50:44 -0700 | [diff] [blame] | 389 | static inline struct dentry * |
| 390 | do_revalidate(struct dentry *dentry, struct nameidata *nd) |
| 391 | { |
| 392 | int status = dentry->d_op->d_revalidate(dentry, nd); |
| 393 | if (unlikely(status <= 0)) { |
| 394 | /* |
| 395 | * The dentry failed validation. |
| 396 | * If d_revalidate returned 0 attempt to invalidate |
| 397 | * the dentry otherwise d_revalidate is asking us |
| 398 | * to return a fail status. |
| 399 | */ |
| 400 | if (!status) { |
| 401 | if (!d_invalidate(dentry)) { |
| 402 | dput(dentry); |
| 403 | dentry = NULL; |
| 404 | } |
| 405 | } else { |
| 406 | dput(dentry); |
| 407 | dentry = ERR_PTR(status); |
| 408 | } |
| 409 | } |
| 410 | return dentry; |
| 411 | } |
| 412 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | /* |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 414 | * force_reval_path - force revalidation of a dentry |
| 415 | * |
| 416 | * In some situations the path walking code will trust dentries without |
| 417 | * revalidating them. This causes problems for filesystems that depend on |
| 418 | * d_revalidate to handle file opens (e.g. NFSv4). When FS_REVAL_DOT is set |
| 419 | * (which indicates that it's possible for the dentry to go stale), force |
| 420 | * a d_revalidate call before proceeding. |
| 421 | * |
| 422 | * Returns 0 if the revalidation was successful. If the revalidation fails, |
| 423 | * either return the error returned by d_revalidate or -ESTALE if the |
| 424 | * revalidation it just returned 0. If d_revalidate returns 0, we attempt to |
| 425 | * invalidate the dentry. It's up to the caller to handle putting references |
| 426 | * to the path if necessary. |
| 427 | */ |
| 428 | static int |
| 429 | force_reval_path(struct path *path, struct nameidata *nd) |
| 430 | { |
| 431 | int status; |
| 432 | struct dentry *dentry = path->dentry; |
| 433 | |
| 434 | /* |
| 435 | * only check on filesystems where it's possible for the dentry to |
| 436 | * become stale. It's assumed that if this flag is set then the |
| 437 | * d_revalidate op will also be defined. |
| 438 | */ |
| 439 | if (!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) |
| 440 | return 0; |
| 441 | |
| 442 | status = dentry->d_op->d_revalidate(dentry, nd); |
| 443 | if (status > 0) |
| 444 | return 0; |
| 445 | |
| 446 | if (!status) { |
| 447 | d_invalidate(dentry); |
| 448 | status = -ESTALE; |
| 449 | } |
| 450 | return status; |
| 451 | } |
| 452 | |
| 453 | /* |
Al Viro | b75b508 | 2009-12-16 01:01:38 -0500 | [diff] [blame] | 454 | * Short-cut version of permission(), for calling on directories |
| 455 | * during pathname resolution. Combines parts of permission() |
| 456 | * and generic_permission(), and tests ONLY for MAY_EXEC permission. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | * |
| 458 | * If appropriate, check DAC only. If not appropriate, or |
Al Viro | b75b508 | 2009-12-16 01:01:38 -0500 | [diff] [blame] | 459 | * short-cut DAC fails, then call ->permission() to do more |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | * complete permission check. |
| 461 | */ |
Al Viro | b75b508 | 2009-12-16 01:01:38 -0500 | [diff] [blame] | 462 | static int exec_permission(struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | { |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 464 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 465 | |
Linus Torvalds | cb9179e | 2009-08-28 11:08:31 -0700 | [diff] [blame] | 466 | if (inode->i_op->permission) { |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 467 | ret = inode->i_op->permission(inode, MAY_EXEC); |
Linus Torvalds | cb9179e | 2009-08-28 11:08:31 -0700 | [diff] [blame] | 468 | if (!ret) |
| 469 | goto ok; |
| 470 | return ret; |
| 471 | } |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 472 | ret = acl_permission_check(inode, MAY_EXEC, inode->i_op->check_acl); |
| 473 | if (!ret) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 474 | goto ok; |
| 475 | |
Linus Torvalds | f1ac9f6 | 2009-08-28 10:53:56 -0700 | [diff] [blame] | 476 | if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | goto ok; |
| 478 | |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 479 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | ok: |
Al Viro | b77b064 | 2008-07-17 09:37:02 -0400 | [diff] [blame] | 481 | return security_inode_permission(inode, MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | } |
| 483 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 484 | static __always_inline void set_root(struct nameidata *nd) |
| 485 | { |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 486 | if (!nd->root.mnt) |
| 487 | get_fs_root(current->fs, &nd->root); |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 488 | } |
| 489 | |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 490 | static int link_path_walk(const char *, struct nameidata *); |
| 491 | |
Arjan van de Ven | f166235 | 2006-01-14 13:21:31 -0800 | [diff] [blame] | 492 | 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] | 493 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | if (IS_ERR(link)) |
| 495 | goto fail; |
| 496 | |
| 497 | if (*link == '/') { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 498 | set_root(nd); |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 499 | path_put(&nd->path); |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 500 | nd->path = nd->root; |
| 501 | path_get(&nd->root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | } |
Christoph Hellwig | b4091d5 | 2008-11-05 15:07:21 +0100 | [diff] [blame] | 503 | |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 504 | return link_path_walk(link, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | fail: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 506 | path_put(&nd->path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | return PTR_ERR(link); |
| 508 | } |
| 509 | |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 510 | static void path_put_conditional(struct path *path, struct nameidata *nd) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 511 | { |
| 512 | dput(path->dentry); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 513 | if (path->mnt != nd->path.mnt) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 514 | mntput(path->mnt); |
| 515 | } |
| 516 | |
| 517 | static inline void path_to_nameidata(struct path *path, struct nameidata *nd) |
| 518 | { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 519 | dput(nd->path.dentry); |
Huang Shijie | 9a22968 | 2010-04-02 17:37:13 +0800 | [diff] [blame] | 520 | if (nd->path.mnt != path->mnt) { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 521 | mntput(nd->path.mnt); |
Huang Shijie | 9a22968 | 2010-04-02 17:37:13 +0800 | [diff] [blame] | 522 | nd->path.mnt = path->mnt; |
| 523 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 524 | nd->path.dentry = path->dentry; |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 525 | } |
| 526 | |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 527 | static __always_inline int |
| 528 | __do_follow_link(struct path *path, struct nameidata *nd, void **p) |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 529 | { |
| 530 | int error; |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 531 | struct dentry *dentry = path->dentry; |
| 532 | |
| 533 | touch_atime(path->mnt, dentry); |
| 534 | nd_set_link(nd, NULL); |
| 535 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 536 | if (path->mnt != nd->path.mnt) { |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 537 | path_to_nameidata(path, nd); |
| 538 | dget(dentry); |
| 539 | } |
| 540 | mntget(path->mnt); |
Al Viro | 86acdca1 | 2009-12-22 23:45:11 -0500 | [diff] [blame] | 541 | nd->last_type = LAST_BIND; |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 542 | *p = dentry->d_inode->i_op->follow_link(dentry, nd); |
| 543 | error = PTR_ERR(*p); |
| 544 | if (!IS_ERR(*p)) { |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 545 | char *s = nd_get_link(nd); |
| 546 | error = 0; |
| 547 | if (s) |
| 548 | error = __vfs_follow_link(nd, s); |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 549 | else if (nd->last_type == LAST_BIND) { |
| 550 | error = force_reval_path(&nd->path, nd); |
| 551 | if (error) |
| 552 | path_put(&nd->path); |
| 553 | } |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 554 | } |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 555 | return error; |
| 556 | } |
| 557 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | /* |
| 559 | * This limits recursive symlink follows to 8, while |
| 560 | * limiting consecutive symlinks to 40. |
| 561 | * |
| 562 | * Without that kind of total limit, nasty chains of consecutive |
| 563 | * symlinks can cause almost arbitrarily long lookups. |
| 564 | */ |
Al Viro | 90ebe56 | 2005-06-06 13:35:58 -0700 | [diff] [blame] | 565 | static inline int do_follow_link(struct path *path, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | { |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 567 | void *cookie; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | int err = -ELOOP; |
| 569 | if (current->link_count >= MAX_NESTED_LINKS) |
| 570 | goto loop; |
| 571 | if (current->total_link_count >= 40) |
| 572 | goto loop; |
| 573 | BUG_ON(nd->depth >= MAX_NESTED_LINKS); |
| 574 | cond_resched(); |
Al Viro | 90ebe56 | 2005-06-06 13:35:58 -0700 | [diff] [blame] | 575 | err = security_inode_follow_link(path->dentry, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 576 | if (err) |
| 577 | goto loop; |
| 578 | current->link_count++; |
| 579 | current->total_link_count++; |
| 580 | nd->depth++; |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 581 | err = __do_follow_link(path, nd, &cookie); |
| 582 | if (!IS_ERR(cookie) && path->dentry->d_inode->i_op->put_link) |
| 583 | path->dentry->d_inode->i_op->put_link(path->dentry, nd, cookie); |
Al Viro | 258fa99 | 2009-08-09 01:32:02 +0400 | [diff] [blame] | 584 | path_put(path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | current->link_count--; |
| 586 | nd->depth--; |
| 587 | return err; |
| 588 | loop: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 589 | path_put_conditional(path, nd); |
| 590 | path_put(&nd->path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | return err; |
| 592 | } |
| 593 | |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 594 | int follow_up(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | { |
| 596 | struct vfsmount *parent; |
| 597 | struct dentry *mountpoint; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 598 | |
| 599 | br_read_lock(vfsmount_lock); |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 600 | parent = path->mnt->mnt_parent; |
| 601 | if (parent == path->mnt) { |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 602 | br_read_unlock(vfsmount_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 603 | return 0; |
| 604 | } |
| 605 | mntget(parent); |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 606 | mountpoint = dget(path->mnt->mnt_mountpoint); |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 607 | br_read_unlock(vfsmount_lock); |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 608 | dput(path->dentry); |
| 609 | path->dentry = mountpoint; |
| 610 | mntput(path->mnt); |
| 611 | path->mnt = parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | return 1; |
| 613 | } |
| 614 | |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame^] | 615 | /* |
| 616 | * serialization is taken care of in namespace.c |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | */ |
Al Viro | 463ffb2 | 2005-06-06 13:36:05 -0700 | [diff] [blame] | 618 | static int __follow_mount(struct path *path) |
| 619 | { |
| 620 | int res = 0; |
| 621 | while (d_mountpoint(path->dentry)) { |
Al Viro | 1c755af | 2009-04-18 14:06:57 -0400 | [diff] [blame] | 622 | struct vfsmount *mounted = lookup_mnt(path); |
Al Viro | 463ffb2 | 2005-06-06 13:36:05 -0700 | [diff] [blame] | 623 | if (!mounted) |
| 624 | break; |
| 625 | dput(path->dentry); |
| 626 | if (res) |
| 627 | mntput(path->mnt); |
| 628 | path->mnt = mounted; |
| 629 | path->dentry = dget(mounted->mnt_root); |
| 630 | res = 1; |
| 631 | } |
| 632 | return res; |
| 633 | } |
| 634 | |
Al Viro | 79ed022 | 2009-04-18 13:59:41 -0400 | [diff] [blame] | 635 | static void follow_mount(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 636 | { |
Al Viro | 79ed022 | 2009-04-18 13:59:41 -0400 | [diff] [blame] | 637 | while (d_mountpoint(path->dentry)) { |
Al Viro | 1c755af | 2009-04-18 14:06:57 -0400 | [diff] [blame] | 638 | struct vfsmount *mounted = lookup_mnt(path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 639 | if (!mounted) |
| 640 | break; |
Al Viro | 79ed022 | 2009-04-18 13:59:41 -0400 | [diff] [blame] | 641 | dput(path->dentry); |
| 642 | mntput(path->mnt); |
| 643 | path->mnt = mounted; |
| 644 | path->dentry = dget(mounted->mnt_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 645 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | } |
| 647 | |
Al Viro | 9393bd0 | 2009-04-18 13:58:15 -0400 | [diff] [blame] | 648 | int follow_down(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | { |
| 650 | struct vfsmount *mounted; |
| 651 | |
Al Viro | 1c755af | 2009-04-18 14:06:57 -0400 | [diff] [blame] | 652 | mounted = lookup_mnt(path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 653 | if (mounted) { |
Al Viro | 9393bd0 | 2009-04-18 13:58:15 -0400 | [diff] [blame] | 654 | dput(path->dentry); |
| 655 | mntput(path->mnt); |
| 656 | path->mnt = mounted; |
| 657 | path->dentry = dget(mounted->mnt_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 658 | return 1; |
| 659 | } |
| 660 | return 0; |
| 661 | } |
| 662 | |
Arjan van de Ven | f166235 | 2006-01-14 13:21:31 -0800 | [diff] [blame] | 663 | static __always_inline void follow_dotdot(struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 665 | set_root(nd); |
Andreas Mohr | e518ddb | 2006-09-29 02:01:22 -0700 | [diff] [blame] | 666 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 667 | while(1) { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 668 | struct dentry *old = nd->path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 669 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 670 | if (nd->path.dentry == nd->root.dentry && |
| 671 | nd->path.mnt == nd->root.mnt) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | break; |
| 673 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 674 | if (nd->path.dentry != nd->path.mnt->mnt_root) { |
Al Viro | 3088dd7 | 2010-01-30 15:47:29 -0500 | [diff] [blame] | 675 | /* rare case of legitimate dget_parent()... */ |
| 676 | nd->path.dentry = dget_parent(nd->path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 677 | dput(old); |
| 678 | break; |
| 679 | } |
Al Viro | 3088dd7 | 2010-01-30 15:47:29 -0500 | [diff] [blame] | 680 | if (!follow_up(&nd->path)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 682 | } |
Al Viro | 79ed022 | 2009-04-18 13:59:41 -0400 | [diff] [blame] | 683 | follow_mount(&nd->path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | } |
| 685 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 686 | /* |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 687 | * Allocate a dentry with name and parent, and perform a parent |
| 688 | * directory ->lookup on it. Returns the new dentry, or ERR_PTR |
| 689 | * on error. parent->d_inode->i_mutex must be held. d_lookup must |
| 690 | * have verified that no child exists while under i_mutex. |
| 691 | */ |
| 692 | static struct dentry *d_alloc_and_lookup(struct dentry *parent, |
| 693 | struct qstr *name, struct nameidata *nd) |
| 694 | { |
| 695 | struct inode *inode = parent->d_inode; |
| 696 | struct dentry *dentry; |
| 697 | struct dentry *old; |
| 698 | |
| 699 | /* Don't create child dentry for a dead directory. */ |
| 700 | if (unlikely(IS_DEADDIR(inode))) |
| 701 | return ERR_PTR(-ENOENT); |
| 702 | |
| 703 | dentry = d_alloc(parent, name); |
| 704 | if (unlikely(!dentry)) |
| 705 | return ERR_PTR(-ENOMEM); |
| 706 | |
| 707 | old = inode->i_op->lookup(inode, dentry, nd); |
| 708 | if (unlikely(old)) { |
| 709 | dput(dentry); |
| 710 | dentry = old; |
| 711 | } |
| 712 | return dentry; |
| 713 | } |
| 714 | |
| 715 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 716 | * It's more convoluted than I'd like it to be, but... it's still fairly |
| 717 | * small and for now I'd prefer to have fast path as straight as possible. |
| 718 | * It _is_ time-critical. |
| 719 | */ |
| 720 | static int do_lookup(struct nameidata *nd, struct qstr *name, |
| 721 | struct path *path) |
| 722 | { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 723 | struct vfsmount *mnt = nd->path.mnt; |
Al Viro | 6e6b1bd | 2009-08-13 23:38:37 +0400 | [diff] [blame] | 724 | struct dentry *dentry, *parent; |
| 725 | struct inode *dir; |
Al Viro | 3cac260 | 2009-08-13 18:27:43 +0400 | [diff] [blame] | 726 | /* |
| 727 | * See if the low-level filesystem might want |
| 728 | * to use its own hash.. |
| 729 | */ |
| 730 | if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { |
Nick Piggin | b1e6a01 | 2011-01-07 17:49:28 +1100 | [diff] [blame] | 731 | int err = nd->path.dentry->d_op->d_hash(nd->path.dentry, |
| 732 | nd->path.dentry->d_inode, name); |
Al Viro | 3cac260 | 2009-08-13 18:27:43 +0400 | [diff] [blame] | 733 | if (err < 0) |
| 734 | return err; |
| 735 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 736 | |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 737 | /* |
| 738 | * Rename seqlock is not required here because in the off chance |
| 739 | * of a false negative due to a concurrent rename, we're going to |
| 740 | * do the non-racy lookup, below. |
| 741 | */ |
Al Viro | 3cac260 | 2009-08-13 18:27:43 +0400 | [diff] [blame] | 742 | dentry = __d_lookup(nd->path.dentry, name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 743 | if (!dentry) |
| 744 | goto need_lookup; |
Nick Piggin | 2e2e88e | 2010-08-18 04:37:30 +1000 | [diff] [blame] | 745 | found: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 746 | if (dentry->d_op && dentry->d_op->d_revalidate) |
| 747 | goto need_revalidate; |
| 748 | done: |
| 749 | path->mnt = mnt; |
| 750 | path->dentry = dentry; |
Al Viro | 634ee70 | 2005-06-06 13:36:13 -0700 | [diff] [blame] | 751 | __follow_mount(path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 752 | return 0; |
| 753 | |
| 754 | need_lookup: |
Al Viro | 6e6b1bd | 2009-08-13 23:38:37 +0400 | [diff] [blame] | 755 | parent = nd->path.dentry; |
| 756 | dir = parent->d_inode; |
| 757 | |
| 758 | mutex_lock(&dir->i_mutex); |
| 759 | /* |
| 760 | * First re-do the cached lookup just in case it was created |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 761 | * while we waited for the directory semaphore, or the first |
| 762 | * lookup failed due to an unrelated rename. |
Al Viro | 6e6b1bd | 2009-08-13 23:38:37 +0400 | [diff] [blame] | 763 | * |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 764 | * This could use version numbering or similar to avoid unnecessary |
| 765 | * cache lookups, but then we'd have to do the first lookup in the |
| 766 | * non-racy way. However in the common case here, everything should |
| 767 | * be hot in cache, so would it be a big win? |
Al Viro | 6e6b1bd | 2009-08-13 23:38:37 +0400 | [diff] [blame] | 768 | */ |
| 769 | dentry = d_lookup(parent, name); |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 770 | if (likely(!dentry)) { |
| 771 | dentry = d_alloc_and_lookup(parent, name, nd); |
Al Viro | 6e6b1bd | 2009-08-13 23:38:37 +0400 | [diff] [blame] | 772 | mutex_unlock(&dir->i_mutex); |
| 773 | if (IS_ERR(dentry)) |
| 774 | goto fail; |
| 775 | goto done; |
| 776 | } |
Al Viro | 6e6b1bd | 2009-08-13 23:38:37 +0400 | [diff] [blame] | 777 | /* |
| 778 | * Uhhuh! Nasty case: the cache was re-populated while |
| 779 | * we waited on the semaphore. Need to revalidate. |
| 780 | */ |
| 781 | mutex_unlock(&dir->i_mutex); |
Nick Piggin | 2e2e88e | 2010-08-18 04:37:30 +1000 | [diff] [blame] | 782 | goto found; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 783 | |
| 784 | need_revalidate: |
Ian Kent | bcdc5e0 | 2006-09-27 01:50:44 -0700 | [diff] [blame] | 785 | dentry = do_revalidate(dentry, nd); |
| 786 | if (!dentry) |
| 787 | goto need_lookup; |
| 788 | if (IS_ERR(dentry)) |
| 789 | goto fail; |
| 790 | goto done; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 791 | |
| 792 | fail: |
| 793 | return PTR_ERR(dentry); |
| 794 | } |
| 795 | |
| 796 | /* |
Al Viro | ac278a9 | 2010-02-16 18:09:36 +0000 | [diff] [blame] | 797 | * This is a temporary kludge to deal with "automount" symlinks; proper |
| 798 | * solution is to trigger them on follow_mount(), so that do_lookup() |
| 799 | * would DTRT. To be killed before 2.6.34-final. |
| 800 | */ |
| 801 | static inline int follow_on_final(struct inode *inode, unsigned lookup_flags) |
| 802 | { |
| 803 | return inode && unlikely(inode->i_op->follow_link) && |
| 804 | ((lookup_flags & LOOKUP_FOLLOW) || S_ISDIR(inode->i_mode)); |
| 805 | } |
| 806 | |
| 807 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | * Name resolution. |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 809 | * This is the basic name resolution function, turning a pathname into |
| 810 | * the final dentry. We expect 'base' to be positive and a directory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 811 | * |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 812 | * Returns 0 and nd will have valid dentry and mnt on success. |
| 813 | * Returns error and drops reference to input namei data on failure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 814 | */ |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 815 | static int link_path_walk(const char *name, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 816 | { |
| 817 | struct path next; |
| 818 | struct inode *inode; |
| 819 | int err; |
| 820 | unsigned int lookup_flags = nd->flags; |
| 821 | |
| 822 | while (*name=='/') |
| 823 | name++; |
| 824 | if (!*name) |
| 825 | goto return_reval; |
| 826 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 827 | inode = nd->path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 828 | if (nd->depth) |
Trond Myklebust | f55eab8 | 2006-02-04 23:28:01 -0800 | [diff] [blame] | 829 | lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 830 | |
| 831 | /* At this point we know we have a real path component. */ |
| 832 | for(;;) { |
| 833 | unsigned long hash; |
| 834 | struct qstr this; |
| 835 | unsigned int c; |
| 836 | |
Trond Myklebust | cdce5d6 | 2005-10-18 14:20:18 -0700 | [diff] [blame] | 837 | nd->flags |= LOOKUP_CONTINUE; |
Al Viro | b75b508 | 2009-12-16 01:01:38 -0500 | [diff] [blame] | 838 | err = exec_permission(inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 839 | if (err) |
| 840 | break; |
| 841 | |
| 842 | this.name = name; |
| 843 | c = *(const unsigned char *)name; |
| 844 | |
| 845 | hash = init_name_hash(); |
| 846 | do { |
| 847 | name++; |
| 848 | hash = partial_name_hash(c, hash); |
| 849 | c = *(const unsigned char *)name; |
| 850 | } while (c && (c != '/')); |
| 851 | this.len = name - (const char *) this.name; |
| 852 | this.hash = end_name_hash(hash); |
| 853 | |
| 854 | /* remove trailing slashes? */ |
| 855 | if (!c) |
| 856 | goto last_component; |
| 857 | while (*++name == '/'); |
| 858 | if (!*name) |
| 859 | goto last_with_slashes; |
| 860 | |
| 861 | /* |
| 862 | * "." and ".." are special - ".." especially so because it has |
| 863 | * to be able to know about the current root directory and |
| 864 | * parent relationships. |
| 865 | */ |
| 866 | if (this.name[0] == '.') switch (this.len) { |
| 867 | default: |
| 868 | break; |
| 869 | case 2: |
| 870 | if (this.name[1] != '.') |
| 871 | break; |
Al Viro | 58c465e | 2005-06-06 13:36:13 -0700 | [diff] [blame] | 872 | follow_dotdot(nd); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 873 | inode = nd->path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 874 | /* fallthrough */ |
| 875 | case 1: |
| 876 | continue; |
| 877 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 878 | /* This does the actual lookups.. */ |
| 879 | err = do_lookup(nd, &this, &next); |
| 880 | if (err) |
| 881 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 882 | |
| 883 | err = -ENOENT; |
| 884 | inode = next.dentry->d_inode; |
| 885 | if (!inode) |
| 886 | goto out_dput; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | |
| 888 | if (inode->i_op->follow_link) { |
Al Viro | 90ebe56 | 2005-06-06 13:35:58 -0700 | [diff] [blame] | 889 | err = do_follow_link(&next, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 890 | if (err) |
| 891 | goto return_err; |
| 892 | err = -ENOENT; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 893 | inode = nd->path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 894 | if (!inode) |
| 895 | break; |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 896 | } else |
| 897 | path_to_nameidata(&next, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 898 | err = -ENOTDIR; |
| 899 | if (!inode->i_op->lookup) |
| 900 | break; |
| 901 | continue; |
| 902 | /* here ends the main loop */ |
| 903 | |
| 904 | last_with_slashes: |
| 905 | lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
| 906 | last_component: |
Trond Myklebust | f55eab8 | 2006-02-04 23:28:01 -0800 | [diff] [blame] | 907 | /* Clear LOOKUP_CONTINUE iff it was previously unset */ |
| 908 | nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 909 | if (lookup_flags & LOOKUP_PARENT) |
| 910 | goto lookup_parent; |
| 911 | if (this.name[0] == '.') switch (this.len) { |
| 912 | default: |
| 913 | break; |
| 914 | case 2: |
| 915 | if (this.name[1] != '.') |
| 916 | break; |
Al Viro | 58c465e | 2005-06-06 13:36:13 -0700 | [diff] [blame] | 917 | follow_dotdot(nd); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 918 | inode = nd->path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 919 | /* fallthrough */ |
| 920 | case 1: |
| 921 | goto return_reval; |
| 922 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 923 | err = do_lookup(nd, &this, &next); |
| 924 | if (err) |
| 925 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 926 | inode = next.dentry->d_inode; |
Al Viro | ac278a9 | 2010-02-16 18:09:36 +0000 | [diff] [blame] | 927 | if (follow_on_final(inode, lookup_flags)) { |
Al Viro | 90ebe56 | 2005-06-06 13:35:58 -0700 | [diff] [blame] | 928 | err = do_follow_link(&next, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 929 | if (err) |
| 930 | goto return_err; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 931 | inode = nd->path.dentry->d_inode; |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 932 | } else |
| 933 | path_to_nameidata(&next, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 934 | err = -ENOENT; |
| 935 | if (!inode) |
| 936 | break; |
| 937 | if (lookup_flags & LOOKUP_DIRECTORY) { |
| 938 | err = -ENOTDIR; |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 939 | if (!inode->i_op->lookup) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 940 | break; |
| 941 | } |
| 942 | goto return_base; |
| 943 | lookup_parent: |
| 944 | nd->last = this; |
| 945 | nd->last_type = LAST_NORM; |
| 946 | if (this.name[0] != '.') |
| 947 | goto return_base; |
| 948 | if (this.len == 1) |
| 949 | nd->last_type = LAST_DOT; |
| 950 | else if (this.len == 2 && this.name[1] == '.') |
| 951 | nd->last_type = LAST_DOTDOT; |
| 952 | else |
| 953 | goto return_base; |
| 954 | return_reval: |
| 955 | /* |
| 956 | * We bypassed the ordinary revalidation routines. |
| 957 | * We may need to check the cached dentry for staleness. |
| 958 | */ |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 959 | if (nd->path.dentry && nd->path.dentry->d_sb && |
| 960 | (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 961 | err = -ESTALE; |
| 962 | /* Note: we do not d_invalidate() */ |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 963 | if (!nd->path.dentry->d_op->d_revalidate( |
| 964 | nd->path.dentry, nd)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 965 | break; |
| 966 | } |
| 967 | return_base: |
| 968 | return 0; |
| 969 | out_dput: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 970 | path_put_conditional(&next, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | break; |
| 972 | } |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 973 | path_put(&nd->path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 974 | return_err: |
| 975 | return err; |
| 976 | } |
| 977 | |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 978 | static int path_walk(const char *name, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 979 | { |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 980 | struct path save = nd->path; |
| 981 | int result; |
| 982 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 983 | current->total_link_count = 0; |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 984 | |
| 985 | /* make sure the stuff we saved doesn't go away */ |
| 986 | path_get(&save); |
| 987 | |
| 988 | result = link_path_walk(name, nd); |
| 989 | if (result == -ESTALE) { |
| 990 | /* nd->path had been dropped */ |
| 991 | current->total_link_count = 0; |
| 992 | nd->path = save; |
| 993 | path_get(&nd->path); |
| 994 | nd->flags |= LOOKUP_REVAL; |
| 995 | result = link_path_walk(name, nd); |
| 996 | } |
| 997 | |
| 998 | path_put(&save); |
| 999 | |
| 1000 | return result; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1001 | } |
| 1002 | |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1003 | static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1004 | { |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1005 | int retval = 0; |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1006 | int fput_needed; |
| 1007 | struct file *file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1008 | |
| 1009 | nd->last_type = LAST_ROOT; /* if there are only slashes... */ |
| 1010 | nd->flags = flags; |
| 1011 | nd->depth = 0; |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1012 | nd->root.mnt = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1013 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1014 | if (*name=='/') { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1015 | set_root(nd); |
| 1016 | nd->path = nd->root; |
| 1017 | path_get(&nd->root); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1018 | } else if (dfd == AT_FDCWD) { |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 1019 | get_fs_pwd(current->fs, &nd->path); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1020 | } else { |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1021 | struct dentry *dentry; |
| 1022 | |
| 1023 | file = fget_light(dfd, &fput_needed); |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1024 | retval = -EBADF; |
| 1025 | if (!file) |
Trond Myklebust | 6d09bb6 | 2006-06-04 02:51:37 -0700 | [diff] [blame] | 1026 | goto out_fail; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1027 | |
Josef "Jeff" Sipek | 0f7fc9e | 2006-12-08 02:36:35 -0800 | [diff] [blame] | 1028 | dentry = file->f_path.dentry; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1029 | |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1030 | retval = -ENOTDIR; |
| 1031 | if (!S_ISDIR(dentry->d_inode->i_mode)) |
Trond Myklebust | 6d09bb6 | 2006-06-04 02:51:37 -0700 | [diff] [blame] | 1032 | goto fput_fail; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1033 | |
| 1034 | retval = file_permission(file, MAY_EXEC); |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1035 | if (retval) |
Trond Myklebust | 6d09bb6 | 2006-06-04 02:51:37 -0700 | [diff] [blame] | 1036 | goto fput_fail; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1037 | |
Jan Blunck | 5dd784d | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 1038 | nd->path = file->f_path; |
| 1039 | path_get(&file->f_path); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1040 | |
| 1041 | fput_light(file, fput_needed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1042 | } |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1043 | return 0; |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1044 | |
Trond Myklebust | 6d09bb6 | 2006-06-04 02:51:37 -0700 | [diff] [blame] | 1045 | fput_fail: |
Ulrich Drepper | 170aa3d | 2006-02-04 23:28:02 -0800 | [diff] [blame] | 1046 | fput_light(file, fput_needed); |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1047 | out_fail: |
| 1048 | return retval; |
| 1049 | } |
| 1050 | |
| 1051 | /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ |
| 1052 | static int do_path_lookup(int dfd, const char *name, |
| 1053 | unsigned int flags, struct nameidata *nd) |
| 1054 | { |
| 1055 | int retval = path_init(dfd, name, flags, nd); |
| 1056 | if (!retval) |
| 1057 | retval = path_walk(name, nd); |
| 1058 | if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && |
| 1059 | nd->path.dentry->d_inode)) |
| 1060 | audit_inode(name, nd->path.dentry); |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1061 | if (nd->root.mnt) { |
| 1062 | path_put(&nd->root); |
| 1063 | nd->root.mnt = NULL; |
| 1064 | } |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1065 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1066 | } |
| 1067 | |
Harvey Harrison | fc9b52c | 2008-02-08 04:19:52 -0800 | [diff] [blame] | 1068 | int path_lookup(const char *name, unsigned int flags, |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1069 | struct nameidata *nd) |
| 1070 | { |
| 1071 | return do_path_lookup(AT_FDCWD, name, flags, nd); |
| 1072 | } |
| 1073 | |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 1074 | int kern_path(const char *name, unsigned int flags, struct path *path) |
| 1075 | { |
| 1076 | struct nameidata nd; |
| 1077 | int res = do_path_lookup(AT_FDCWD, name, flags, &nd); |
| 1078 | if (!res) |
| 1079 | *path = nd.path; |
| 1080 | return res; |
| 1081 | } |
| 1082 | |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1083 | /** |
| 1084 | * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair |
| 1085 | * @dentry: pointer to dentry of the base directory |
| 1086 | * @mnt: pointer to vfs mount of the base directory |
| 1087 | * @name: pointer to file name |
| 1088 | * @flags: lookup flags |
| 1089 | * @nd: pointer to nameidata |
| 1090 | */ |
| 1091 | int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, |
| 1092 | const char *name, unsigned int flags, |
| 1093 | struct nameidata *nd) |
| 1094 | { |
| 1095 | int retval; |
| 1096 | |
| 1097 | /* same as do_path_lookup */ |
| 1098 | nd->last_type = LAST_ROOT; |
| 1099 | nd->flags = flags; |
| 1100 | nd->depth = 0; |
| 1101 | |
Jan Blunck | c8e7f44 | 2008-06-09 16:40:35 -0700 | [diff] [blame] | 1102 | nd->path.dentry = dentry; |
| 1103 | nd->path.mnt = mnt; |
| 1104 | path_get(&nd->path); |
Al Viro | 5b85711 | 2009-04-07 11:53:49 -0400 | [diff] [blame] | 1105 | nd->root = nd->path; |
| 1106 | path_get(&nd->root); |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1107 | |
| 1108 | retval = path_walk(name, nd); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1109 | if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && |
| 1110 | nd->path.dentry->d_inode)) |
| 1111 | audit_inode(name, nd->path.dentry); |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1112 | |
Al Viro | 5b85711 | 2009-04-07 11:53:49 -0400 | [diff] [blame] | 1113 | path_put(&nd->root); |
| 1114 | nd->root.mnt = NULL; |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1115 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1116 | return retval; |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 1117 | } |
| 1118 | |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1119 | static struct dentry *__lookup_hash(struct qstr *name, |
| 1120 | struct dentry *base, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1121 | { |
Christoph Hellwig | 81fca44 | 2010-10-06 10:47:47 +0200 | [diff] [blame] | 1122 | struct inode *inode = base->d_inode; |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1123 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1124 | int err; |
| 1125 | |
Christoph Hellwig | 81fca44 | 2010-10-06 10:47:47 +0200 | [diff] [blame] | 1126 | err = exec_permission(inode); |
| 1127 | if (err) |
| 1128 | return ERR_PTR(err); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1129 | |
| 1130 | /* |
| 1131 | * See if the low-level filesystem might want |
| 1132 | * to use its own hash.. |
| 1133 | */ |
| 1134 | if (base->d_op && base->d_op->d_hash) { |
Nick Piggin | b1e6a01 | 2011-01-07 17:49:28 +1100 | [diff] [blame] | 1135 | err = base->d_op->d_hash(base, inode, name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1136 | dentry = ERR_PTR(err); |
| 1137 | if (err < 0) |
| 1138 | goto out; |
| 1139 | } |
| 1140 | |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1141 | /* |
| 1142 | * Don't bother with __d_lookup: callers are for creat as |
| 1143 | * well as unlink, so a lot of the time it would cost |
| 1144 | * a double lookup. |
Al Viro | 6e6b1bd | 2009-08-13 23:38:37 +0400 | [diff] [blame] | 1145 | */ |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1146 | dentry = d_lookup(base, name); |
Al Viro | 6e6b1bd | 2009-08-13 23:38:37 +0400 | [diff] [blame] | 1147 | |
| 1148 | if (dentry && dentry->d_op && dentry->d_op->d_revalidate) |
| 1149 | dentry = do_revalidate(dentry, nd); |
| 1150 | |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1151 | if (!dentry) |
| 1152 | dentry = d_alloc_and_lookup(base, name, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1153 | out: |
| 1154 | return dentry; |
| 1155 | } |
| 1156 | |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1157 | /* |
| 1158 | * Restricted form of lookup. Doesn't follow links, single-component only, |
| 1159 | * needs parent already locked. Doesn't follow mounts. |
| 1160 | * SMP-safe. |
| 1161 | */ |
Adrian Bunk | a244e16 | 2006-03-31 02:32:11 -0800 | [diff] [blame] | 1162 | static struct dentry *lookup_hash(struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1163 | { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1164 | return __lookup_hash(&nd->last, nd->path.dentry, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1165 | } |
| 1166 | |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1167 | static int __lookup_one_len(const char *name, struct qstr *this, |
| 1168 | struct dentry *base, int len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1169 | { |
| 1170 | unsigned long hash; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1171 | unsigned int c; |
| 1172 | |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1173 | this->name = name; |
| 1174 | this->len = len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1175 | if (!len) |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1176 | return -EACCES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1177 | |
| 1178 | hash = init_name_hash(); |
| 1179 | while (len--) { |
| 1180 | c = *(const unsigned char *)name++; |
| 1181 | if (c == '/' || c == '\0') |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1182 | return -EACCES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1183 | hash = partial_name_hash(c, hash); |
| 1184 | } |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1185 | this->hash = end_name_hash(hash); |
| 1186 | return 0; |
| 1187 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1188 | |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1189 | /** |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 1190 | * lookup_one_len - filesystem helper to lookup single pathname component |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1191 | * @name: pathname component to lookup |
| 1192 | * @base: base directory to lookup from |
| 1193 | * @len: maximum length @len should be interpreted to |
| 1194 | * |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 1195 | * Note that this routine is purely a helper for filesystem usage and should |
| 1196 | * 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] | 1197 | * nameidata argument is passed to the filesystem methods and a filesystem |
| 1198 | * using this helper needs to be prepared for that. |
| 1199 | */ |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1200 | struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) |
| 1201 | { |
| 1202 | int err; |
| 1203 | struct qstr this; |
| 1204 | |
David Woodhouse | 2f9092e | 2009-04-20 23:18:37 +0100 | [diff] [blame] | 1205 | WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); |
| 1206 | |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1207 | err = __lookup_one_len(name, &this, base, len); |
| 1208 | if (err) |
| 1209 | return ERR_PTR(err); |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 1210 | |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 1211 | return __lookup_hash(&this, base, NULL); |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 1212 | } |
| 1213 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1214 | int user_path_at(int dfd, const char __user *name, unsigned flags, |
| 1215 | struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1216 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1217 | struct nameidata nd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1218 | char *tmp = getname(name); |
| 1219 | int err = PTR_ERR(tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1220 | if (!IS_ERR(tmp)) { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1221 | |
| 1222 | BUG_ON(flags & LOOKUP_PARENT); |
| 1223 | |
| 1224 | err = do_path_lookup(dfd, tmp, flags, &nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1225 | putname(tmp); |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 1226 | if (!err) |
| 1227 | *path = nd.path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1228 | } |
| 1229 | return err; |
| 1230 | } |
| 1231 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 1232 | static int user_path_parent(int dfd, const char __user *path, |
| 1233 | struct nameidata *nd, char **name) |
| 1234 | { |
| 1235 | char *s = getname(path); |
| 1236 | int error; |
| 1237 | |
| 1238 | if (IS_ERR(s)) |
| 1239 | return PTR_ERR(s); |
| 1240 | |
| 1241 | error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd); |
| 1242 | if (error) |
| 1243 | putname(s); |
| 1244 | else |
| 1245 | *name = s; |
| 1246 | |
| 1247 | return error; |
| 1248 | } |
| 1249 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1250 | /* |
| 1251 | * It's inline, so penalty for filesystems that don't use sticky bit is |
| 1252 | * minimal. |
| 1253 | */ |
| 1254 | static inline int check_sticky(struct inode *dir, struct inode *inode) |
| 1255 | { |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 1256 | uid_t fsuid = current_fsuid(); |
| 1257 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1258 | if (!(dir->i_mode & S_ISVTX)) |
| 1259 | return 0; |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 1260 | if (inode->i_uid == fsuid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1261 | return 0; |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 1262 | if (dir->i_uid == fsuid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1263 | return 0; |
| 1264 | return !capable(CAP_FOWNER); |
| 1265 | } |
| 1266 | |
| 1267 | /* |
| 1268 | * Check whether we can remove a link victim from directory dir, check |
| 1269 | * whether the type of victim is right. |
| 1270 | * 1. We can't do it if dir is read-only (done in permission()) |
| 1271 | * 2. We should have write and exec permissions on dir |
| 1272 | * 3. We can't remove anything from append-only dir |
| 1273 | * 4. We can't do anything with immutable dir (done in permission()) |
| 1274 | * 5. If the sticky bit on dir is set we should either |
| 1275 | * a. be owner of dir, or |
| 1276 | * b. be owner of victim, or |
| 1277 | * c. have CAP_FOWNER capability |
| 1278 | * 6. If the victim is append-only or immutable we can't do antyhing with |
| 1279 | * links pointing to it. |
| 1280 | * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. |
| 1281 | * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. |
| 1282 | * 9. We can't remove a root or mountpoint. |
| 1283 | * 10. We don't allow removal of NFS sillyrenamed files; it's handled by |
| 1284 | * nfs_async_unlink(). |
| 1285 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 1286 | static int may_delete(struct inode *dir,struct dentry *victim,int isdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1287 | { |
| 1288 | int error; |
| 1289 | |
| 1290 | if (!victim->d_inode) |
| 1291 | return -ENOENT; |
| 1292 | |
| 1293 | BUG_ON(victim->d_parent->d_inode != dir); |
Al Viro | cccc6bb | 2009-12-25 05:07:33 -0500 | [diff] [blame] | 1294 | audit_inode_child(victim, dir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1295 | |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 1296 | error = inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1297 | if (error) |
| 1298 | return error; |
| 1299 | if (IS_APPEND(dir)) |
| 1300 | return -EPERM; |
| 1301 | if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| |
Hugh Dickins | f945454 | 2008-11-19 15:36:38 -0800 | [diff] [blame] | 1302 | IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1303 | return -EPERM; |
| 1304 | if (isdir) { |
| 1305 | if (!S_ISDIR(victim->d_inode->i_mode)) |
| 1306 | return -ENOTDIR; |
| 1307 | if (IS_ROOT(victim)) |
| 1308 | return -EBUSY; |
| 1309 | } else if (S_ISDIR(victim->d_inode->i_mode)) |
| 1310 | return -EISDIR; |
| 1311 | if (IS_DEADDIR(dir)) |
| 1312 | return -ENOENT; |
| 1313 | if (victim->d_flags & DCACHE_NFSFS_RENAMED) |
| 1314 | return -EBUSY; |
| 1315 | return 0; |
| 1316 | } |
| 1317 | |
| 1318 | /* Check whether we can create an object with dentry child in directory |
| 1319 | * dir. |
| 1320 | * 1. We can't do it if child already exists (open has special treatment for |
| 1321 | * this case, but since we are inlined it's OK) |
| 1322 | * 2. We can't do it if dir is read-only (done in permission()) |
| 1323 | * 3. We should have write and exec permissions on dir |
| 1324 | * 4. We can't do it if dir is immutable (done in permission()) |
| 1325 | */ |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 1326 | static inline int may_create(struct inode *dir, struct dentry *child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1327 | { |
| 1328 | if (child->d_inode) |
| 1329 | return -EEXIST; |
| 1330 | if (IS_DEADDIR(dir)) |
| 1331 | return -ENOENT; |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 1332 | return inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1333 | } |
| 1334 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1335 | /* |
| 1336 | * p1 and p2 should be directories on the same fs. |
| 1337 | */ |
| 1338 | struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) |
| 1339 | { |
| 1340 | struct dentry *p; |
| 1341 | |
| 1342 | if (p1 == p2) { |
Ingo Molnar | f2eace2 | 2006-07-03 00:25:05 -0700 | [diff] [blame] | 1343 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1344 | return NULL; |
| 1345 | } |
| 1346 | |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 1347 | mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1348 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1349 | p = d_ancestor(p2, p1); |
| 1350 | if (p) { |
| 1351 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); |
| 1352 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); |
| 1353 | return p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1354 | } |
| 1355 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 1356 | p = d_ancestor(p1, p2); |
| 1357 | if (p) { |
| 1358 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
| 1359 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); |
| 1360 | return p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1361 | } |
| 1362 | |
Ingo Molnar | f2eace2 | 2006-07-03 00:25:05 -0700 | [diff] [blame] | 1363 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
| 1364 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1365 | return NULL; |
| 1366 | } |
| 1367 | |
| 1368 | void unlock_rename(struct dentry *p1, struct dentry *p2) |
| 1369 | { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1370 | mutex_unlock(&p1->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1371 | if (p1 != p2) { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1372 | mutex_unlock(&p2->d_inode->i_mutex); |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 1373 | mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1374 | } |
| 1375 | } |
| 1376 | |
| 1377 | int vfs_create(struct inode *dir, struct dentry *dentry, int mode, |
| 1378 | struct nameidata *nd) |
| 1379 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 1380 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1381 | |
| 1382 | if (error) |
| 1383 | return error; |
| 1384 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 1385 | if (!dir->i_op->create) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1386 | return -EACCES; /* shouldn't it be ENOSYS? */ |
| 1387 | mode &= S_IALLUGO; |
| 1388 | mode |= S_IFREG; |
| 1389 | error = security_inode_create(dir, dentry, mode); |
| 1390 | if (error) |
| 1391 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1392 | error = dir->i_op->create(dir, dentry, mode, nd); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 1393 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 1394 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1395 | return error; |
| 1396 | } |
| 1397 | |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 1398 | int may_open(struct path *path, int acc_mode, int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1399 | { |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 1400 | struct dentry *dentry = path->dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1401 | struct inode *inode = dentry->d_inode; |
| 1402 | int error; |
| 1403 | |
| 1404 | if (!inode) |
| 1405 | return -ENOENT; |
| 1406 | |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 1407 | switch (inode->i_mode & S_IFMT) { |
| 1408 | case S_IFLNK: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1409 | return -ELOOP; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 1410 | case S_IFDIR: |
| 1411 | if (acc_mode & MAY_WRITE) |
| 1412 | return -EISDIR; |
| 1413 | break; |
| 1414 | case S_IFBLK: |
| 1415 | case S_IFCHR: |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 1416 | if (path->mnt->mnt_flags & MNT_NODEV) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1417 | return -EACCES; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 1418 | /*FALLTHRU*/ |
| 1419 | case S_IFIFO: |
| 1420 | case S_IFSOCK: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1421 | flag &= ~O_TRUNC; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 1422 | break; |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 1423 | } |
Dave Hansen | b41572e | 2007-10-16 23:31:14 -0700 | [diff] [blame] | 1424 | |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 1425 | error = inode_permission(inode, acc_mode); |
Dave Hansen | b41572e | 2007-10-16 23:31:14 -0700 | [diff] [blame] | 1426 | if (error) |
| 1427 | return error; |
Mimi Zohar | 6146f0d | 2009-02-04 09:06:57 -0500 | [diff] [blame] | 1428 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1429 | /* |
| 1430 | * An append-only file must be opened in append mode for writing. |
| 1431 | */ |
| 1432 | if (IS_APPEND(inode)) { |
Al Viro | 8737c93 | 2009-12-24 06:47:55 -0500 | [diff] [blame] | 1433 | if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 1434 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1435 | if (flag & O_TRUNC) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 1436 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1437 | } |
| 1438 | |
| 1439 | /* O_NOATIME can only be set by the owner or superuser */ |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 1440 | if (flag & O_NOATIME && !is_owner_or_cap(inode)) |
| 1441 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1442 | |
| 1443 | /* |
| 1444 | * Ensure there are no outstanding leases on the file. |
| 1445 | */ |
Al Viro | b65a9cf | 2009-12-16 06:27:40 -0500 | [diff] [blame] | 1446 | return break_lease(inode, flag); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 1447 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1448 | |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 1449 | static int handle_truncate(struct path *path) |
| 1450 | { |
| 1451 | struct inode *inode = path->dentry->d_inode; |
| 1452 | int error = get_write_access(inode); |
| 1453 | if (error) |
| 1454 | return error; |
| 1455 | /* |
| 1456 | * Refuse to truncate files with mandatory locks held on them. |
| 1457 | */ |
| 1458 | error = locks_verify_locked(inode); |
| 1459 | if (!error) |
Tetsuo Handa | ea0d3ab | 2010-06-02 13:24:43 +0900 | [diff] [blame] | 1460 | error = security_path_truncate(path); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 1461 | if (!error) { |
| 1462 | error = do_truncate(path->dentry, 0, |
| 1463 | ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, |
| 1464 | NULL); |
| 1465 | } |
| 1466 | put_write_access(inode); |
Mimi Zohar | acd0c93 | 2009-09-04 13:08:46 -0400 | [diff] [blame] | 1467 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1468 | } |
| 1469 | |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 1470 | /* |
| 1471 | * Be careful about ever adding any more callers of this |
| 1472 | * function. Its flags must be in the namei format, not |
| 1473 | * what get passed to sys_open(). |
| 1474 | */ |
| 1475 | static int __open_namei_create(struct nameidata *nd, struct path *path, |
Al Viro | 8737c93 | 2009-12-24 06:47:55 -0500 | [diff] [blame] | 1476 | int open_flag, int mode) |
Dave Hansen | aab520e | 2006-09-30 23:29:02 -0700 | [diff] [blame] | 1477 | { |
| 1478 | int error; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1479 | struct dentry *dir = nd->path.dentry; |
Dave Hansen | aab520e | 2006-09-30 23:29:02 -0700 | [diff] [blame] | 1480 | |
| 1481 | if (!IS_POSIXACL(dir->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 1482 | mode &= ~current_umask(); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 1483 | error = security_path_mknod(&nd->path, path->dentry, mode, 0); |
| 1484 | if (error) |
| 1485 | goto out_unlock; |
Dave Hansen | aab520e | 2006-09-30 23:29:02 -0700 | [diff] [blame] | 1486 | error = vfs_create(dir->d_inode, path->dentry, mode, nd); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 1487 | out_unlock: |
Dave Hansen | aab520e | 2006-09-30 23:29:02 -0700 | [diff] [blame] | 1488 | mutex_unlock(&dir->d_inode->i_mutex); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1489 | dput(nd->path.dentry); |
| 1490 | nd->path.dentry = path->dentry; |
Dave Hansen | aab520e | 2006-09-30 23:29:02 -0700 | [diff] [blame] | 1491 | if (error) |
| 1492 | return error; |
| 1493 | /* Don't check for write permission, don't truncate */ |
Al Viro | 8737c93 | 2009-12-24 06:47:55 -0500 | [diff] [blame] | 1494 | return may_open(&nd->path, 0, open_flag & ~O_TRUNC); |
Dave Hansen | aab520e | 2006-09-30 23:29:02 -0700 | [diff] [blame] | 1495 | } |
| 1496 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1497 | /* |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 1498 | * Note that while the flag value (low two bits) for sys_open means: |
| 1499 | * 00 - read-only |
| 1500 | * 01 - write-only |
| 1501 | * 10 - read-write |
| 1502 | * 11 - special |
| 1503 | * it is changed into |
| 1504 | * 00 - no permissions needed |
| 1505 | * 01 - read-permission |
| 1506 | * 10 - write-permission |
| 1507 | * 11 - read-write |
| 1508 | * for the internal routines (ie open_namei()/follow_link() etc) |
| 1509 | * This is more logical, and also allows the 00 "no perm needed" |
| 1510 | * to be used for symlinks (where the permissions are checked |
| 1511 | * later). |
| 1512 | * |
| 1513 | */ |
| 1514 | static inline int open_to_namei_flags(int flag) |
| 1515 | { |
| 1516 | if ((flag+1) & O_ACCMODE) |
| 1517 | flag++; |
| 1518 | return flag; |
| 1519 | } |
| 1520 | |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 1521 | static int open_will_truncate(int flag, struct inode *inode) |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 1522 | { |
| 1523 | /* |
| 1524 | * We'll never write to the fs underlying |
| 1525 | * a device file. |
| 1526 | */ |
| 1527 | if (special_file(inode->i_mode)) |
| 1528 | return 0; |
| 1529 | return (flag & O_TRUNC); |
| 1530 | } |
| 1531 | |
Al Viro | 648fa86 | 2009-12-24 01:26:48 -0500 | [diff] [blame] | 1532 | static struct file *finish_open(struct nameidata *nd, |
Al Viro | 9a66179 | 2009-12-24 06:49:47 -0500 | [diff] [blame] | 1533 | int open_flag, int acc_mode) |
Al Viro | 648fa86 | 2009-12-24 01:26:48 -0500 | [diff] [blame] | 1534 | { |
| 1535 | struct file *filp; |
| 1536 | int will_truncate; |
| 1537 | int error; |
| 1538 | |
Al Viro | 9a66179 | 2009-12-24 06:49:47 -0500 | [diff] [blame] | 1539 | will_truncate = open_will_truncate(open_flag, nd->path.dentry->d_inode); |
Al Viro | 648fa86 | 2009-12-24 01:26:48 -0500 | [diff] [blame] | 1540 | if (will_truncate) { |
| 1541 | error = mnt_want_write(nd->path.mnt); |
| 1542 | if (error) |
| 1543 | goto exit; |
| 1544 | } |
| 1545 | error = may_open(&nd->path, acc_mode, open_flag); |
| 1546 | if (error) { |
| 1547 | if (will_truncate) |
| 1548 | mnt_drop_write(nd->path.mnt); |
| 1549 | goto exit; |
| 1550 | } |
| 1551 | filp = nameidata_to_filp(nd); |
| 1552 | if (!IS_ERR(filp)) { |
| 1553 | error = ima_file_check(filp, acc_mode); |
| 1554 | if (error) { |
| 1555 | fput(filp); |
| 1556 | filp = ERR_PTR(error); |
| 1557 | } |
| 1558 | } |
| 1559 | if (!IS_ERR(filp)) { |
Al Viro | 648fa86 | 2009-12-24 01:26:48 -0500 | [diff] [blame] | 1560 | if (will_truncate) { |
| 1561 | error = handle_truncate(&nd->path); |
| 1562 | if (error) { |
| 1563 | fput(filp); |
| 1564 | filp = ERR_PTR(error); |
| 1565 | } |
| 1566 | } |
| 1567 | } |
| 1568 | /* |
| 1569 | * It is now safe to drop the mnt write |
| 1570 | * because the filp has had a write taken |
| 1571 | * on its behalf. |
| 1572 | */ |
| 1573 | if (will_truncate) |
| 1574 | mnt_drop_write(nd->path.mnt); |
Al Viro | d893f1b | 2010-10-29 03:30:42 -0400 | [diff] [blame] | 1575 | path_put(&nd->path); |
Al Viro | 648fa86 | 2009-12-24 01:26:48 -0500 | [diff] [blame] | 1576 | return filp; |
| 1577 | |
| 1578 | exit: |
| 1579 | if (!IS_ERR(nd->intent.open.file)) |
| 1580 | release_open_intent(nd); |
| 1581 | path_put(&nd->path); |
| 1582 | return ERR_PTR(error); |
| 1583 | } |
| 1584 | |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1585 | static struct file *do_last(struct nameidata *nd, struct path *path, |
Al Viro | 5b369df | 2009-12-24 06:51:13 -0500 | [diff] [blame] | 1586 | int open_flag, int acc_mode, |
Al Viro | 3e297b6 | 2010-03-26 12:40:13 -0400 | [diff] [blame] | 1587 | int mode, const char *pathname) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1588 | { |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 1589 | struct dentry *dir = nd->path.dentry; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1590 | struct file *filp; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1591 | int error = -EISDIR; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1592 | |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1593 | switch (nd->last_type) { |
| 1594 | case LAST_DOTDOT: |
| 1595 | follow_dotdot(nd); |
| 1596 | dir = nd->path.dentry; |
Neil Brown | 176306f | 2010-05-24 16:57:56 +1000 | [diff] [blame] | 1597 | case LAST_DOT: |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1598 | if (nd->path.mnt->mnt_sb->s_type->fs_flags & FS_REVAL_DOT) { |
| 1599 | if (!dir->d_op->d_revalidate(dir, nd)) { |
| 1600 | error = -ESTALE; |
| 1601 | goto exit; |
| 1602 | } |
| 1603 | } |
| 1604 | /* fallthrough */ |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1605 | case LAST_ROOT: |
| 1606 | if (open_flag & O_CREAT) |
| 1607 | goto exit; |
| 1608 | /* fallthrough */ |
| 1609 | case LAST_BIND: |
| 1610 | audit_inode(pathname, dir); |
Al Viro | 67ee3ad | 2009-12-26 07:01:01 -0500 | [diff] [blame] | 1611 | goto ok; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1612 | } |
Al Viro | 67ee3ad | 2009-12-26 07:01:01 -0500 | [diff] [blame] | 1613 | |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1614 | /* trailing slashes? */ |
| 1615 | if (nd->last.name[nd->last.len]) { |
| 1616 | if (open_flag & O_CREAT) |
| 1617 | goto exit; |
Jan Kara | 002baee | 2010-05-13 12:52:57 +0200 | [diff] [blame] | 1618 | nd->flags |= LOOKUP_DIRECTORY | LOOKUP_FOLLOW; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1619 | } |
Al Viro | a2c36b4 | 2009-12-24 03:39:50 -0500 | [diff] [blame] | 1620 | |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1621 | /* just plain open? */ |
| 1622 | if (!(open_flag & O_CREAT)) { |
| 1623 | error = do_lookup(nd, &nd->last, path); |
| 1624 | if (error) |
| 1625 | goto exit; |
| 1626 | error = -ENOENT; |
| 1627 | if (!path->dentry->d_inode) |
| 1628 | goto exit_dput; |
| 1629 | if (path->dentry->d_inode->i_op->follow_link) |
| 1630 | return NULL; |
| 1631 | error = -ENOTDIR; |
Al Viro | 3e297b6 | 2010-03-26 12:40:13 -0400 | [diff] [blame] | 1632 | if (nd->flags & LOOKUP_DIRECTORY) { |
| 1633 | if (!path->dentry->d_inode->i_op->lookup) |
| 1634 | goto exit_dput; |
| 1635 | } |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1636 | path_to_nameidata(path, nd); |
| 1637 | audit_inode(pathname, nd->path.dentry); |
| 1638 | goto ok; |
| 1639 | } |
| 1640 | |
| 1641 | /* OK, it's O_CREAT */ |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 1642 | mutex_lock(&dir->d_inode->i_mutex); |
| 1643 | |
| 1644 | path->dentry = lookup_hash(nd); |
| 1645 | path->mnt = nd->path.mnt; |
| 1646 | |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1647 | error = PTR_ERR(path->dentry); |
| 1648 | if (IS_ERR(path->dentry)) { |
| 1649 | mutex_unlock(&dir->d_inode->i_mutex); |
| 1650 | goto exit; |
| 1651 | } |
| 1652 | |
| 1653 | if (IS_ERR(nd->intent.open.file)) { |
| 1654 | error = PTR_ERR(nd->intent.open.file); |
| 1655 | goto exit_mutex_unlock; |
| 1656 | } |
| 1657 | |
| 1658 | /* Negative dentry, just create the file */ |
| 1659 | if (!path->dentry->d_inode) { |
| 1660 | /* |
| 1661 | * This write is needed to ensure that a |
| 1662 | * ro->rw transition does not occur between |
| 1663 | * the time when the file is created and when |
| 1664 | * a permanent write count is taken through |
| 1665 | * the 'struct file' in nameidata_to_filp(). |
| 1666 | */ |
| 1667 | error = mnt_want_write(nd->path.mnt); |
| 1668 | if (error) |
| 1669 | goto exit_mutex_unlock; |
| 1670 | error = __open_namei_create(nd, path, open_flag, mode); |
| 1671 | if (error) { |
| 1672 | mnt_drop_write(nd->path.mnt); |
| 1673 | goto exit; |
| 1674 | } |
| 1675 | filp = nameidata_to_filp(nd); |
| 1676 | mnt_drop_write(nd->path.mnt); |
Al Viro | d893f1b | 2010-10-29 03:30:42 -0400 | [diff] [blame] | 1677 | path_put(&nd->path); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1678 | if (!IS_ERR(filp)) { |
| 1679 | error = ima_file_check(filp, acc_mode); |
| 1680 | if (error) { |
| 1681 | fput(filp); |
| 1682 | filp = ERR_PTR(error); |
| 1683 | } |
| 1684 | } |
| 1685 | return filp; |
| 1686 | } |
| 1687 | |
| 1688 | /* |
| 1689 | * It already exists. |
| 1690 | */ |
| 1691 | mutex_unlock(&dir->d_inode->i_mutex); |
| 1692 | audit_inode(pathname, path->dentry); |
| 1693 | |
| 1694 | error = -EEXIST; |
Al Viro | 5b369df | 2009-12-24 06:51:13 -0500 | [diff] [blame] | 1695 | if (open_flag & O_EXCL) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1696 | goto exit_dput; |
| 1697 | |
| 1698 | if (__follow_mount(path)) { |
| 1699 | error = -ELOOP; |
Al Viro | 5b369df | 2009-12-24 06:51:13 -0500 | [diff] [blame] | 1700 | if (open_flag & O_NOFOLLOW) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1701 | goto exit_dput; |
| 1702 | } |
| 1703 | |
| 1704 | error = -ENOENT; |
| 1705 | if (!path->dentry->d_inode) |
| 1706 | goto exit_dput; |
Al Viro | 9e67f36 | 2009-12-26 07:04:50 -0500 | [diff] [blame] | 1707 | |
| 1708 | if (path->dentry->d_inode->i_op->follow_link) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1709 | return NULL; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1710 | |
| 1711 | path_to_nameidata(path, nd); |
| 1712 | error = -EISDIR; |
| 1713 | if (S_ISDIR(path->dentry->d_inode->i_mode)) |
| 1714 | goto exit; |
Al Viro | 67ee3ad | 2009-12-26 07:01:01 -0500 | [diff] [blame] | 1715 | ok: |
Al Viro | 9a66179 | 2009-12-24 06:49:47 -0500 | [diff] [blame] | 1716 | filp = finish_open(nd, open_flag, acc_mode); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1717 | return filp; |
| 1718 | |
| 1719 | exit_mutex_unlock: |
| 1720 | mutex_unlock(&dir->d_inode->i_mutex); |
| 1721 | exit_dput: |
| 1722 | path_put_conditional(path, nd); |
| 1723 | exit: |
| 1724 | if (!IS_ERR(nd->intent.open.file)) |
| 1725 | release_open_intent(nd); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 1726 | path_put(&nd->path); |
| 1727 | return ERR_PTR(error); |
| 1728 | } |
| 1729 | |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 1730 | /* |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 1731 | * Note that the low bits of the passed in "open_flag" |
| 1732 | * are not the same as in the local variable "flag". See |
| 1733 | * open_to_namei_flags() for more details. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1734 | */ |
Christoph Hellwig | a70e65d | 2008-02-15 14:37:28 -0800 | [diff] [blame] | 1735 | struct file *do_filp_open(int dfd, const char *pathname, |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 1736 | int open_flag, int mode, int acc_mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1737 | { |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 1738 | struct file *filp; |
Christoph Hellwig | a70e65d | 2008-02-15 14:37:28 -0800 | [diff] [blame] | 1739 | struct nameidata nd; |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 1740 | int error; |
Al Viro | 9850c05 | 2010-01-13 15:01:15 -0500 | [diff] [blame] | 1741 | struct path path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1742 | int count = 0; |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 1743 | int flag = open_to_namei_flags(open_flag); |
Al Viro | 9850c05 | 2010-01-13 15:01:15 -0500 | [diff] [blame] | 1744 | int force_reval = 0; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1745 | |
| 1746 | if (!(open_flag & O_CREAT)) |
| 1747 | mode = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1748 | |
Lino Sanfilippo | b1085ba | 2010-11-05 17:05:27 +0100 | [diff] [blame] | 1749 | /* Must never be set by userspace */ |
| 1750 | open_flag &= ~FMODE_NONOTIFY; |
| 1751 | |
Christoph Hellwig | 6b2f3d1 | 2009-10-27 11:05:28 +0100 | [diff] [blame] | 1752 | /* |
| 1753 | * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only |
| 1754 | * check for O_DSYNC if the need any syncing at all we enforce it's |
| 1755 | * always set instead of having to deal with possibly weird behaviour |
| 1756 | * for malicious applications setting only __O_SYNC. |
| 1757 | */ |
| 1758 | if (open_flag & __O_SYNC) |
| 1759 | open_flag |= O_DSYNC; |
| 1760 | |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 1761 | if (!acc_mode) |
Al Viro | 6d12552 | 2009-12-24 06:58:56 -0500 | [diff] [blame] | 1762 | acc_mode = MAY_OPEN | ACC_MODE(open_flag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1763 | |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 1764 | /* O_TRUNC implies we need access checks for write permissions */ |
Al Viro | 4296e2c | 2009-12-24 07:15:41 -0500 | [diff] [blame] | 1765 | if (open_flag & O_TRUNC) |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 1766 | acc_mode |= MAY_WRITE; |
| 1767 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1768 | /* Allow the LSM permission hook to distinguish append |
| 1769 | access from general write access. */ |
Al Viro | 4296e2c | 2009-12-24 07:15:41 -0500 | [diff] [blame] | 1770 | if (open_flag & O_APPEND) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1771 | acc_mode |= MAY_APPEND; |
| 1772 | |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1773 | /* find the parent */ |
Al Viro | 9850c05 | 2010-01-13 15:01:15 -0500 | [diff] [blame] | 1774 | reval: |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1775 | error = path_init(dfd, pathname, LOOKUP_PARENT, &nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1776 | if (error) |
Christoph Hellwig | a70e65d | 2008-02-15 14:37:28 -0800 | [diff] [blame] | 1777 | return ERR_PTR(error); |
Al Viro | 9850c05 | 2010-01-13 15:01:15 -0500 | [diff] [blame] | 1778 | if (force_reval) |
| 1779 | nd.flags |= LOOKUP_REVAL; |
Al Viro | 3866248 | 2009-12-26 07:21:48 -0500 | [diff] [blame] | 1780 | |
| 1781 | current->total_link_count = 0; |
| 1782 | error = link_path_walk(pathname, &nd); |
J. R. Okajima | 654f562 | 2009-06-18 23:30:15 +0900 | [diff] [blame] | 1783 | if (error) { |
Al Viro | 10fa8e6 | 2009-12-26 07:09:49 -0500 | [diff] [blame] | 1784 | filp = ERR_PTR(error); |
| 1785 | goto out; |
J. R. Okajima | 654f562 | 2009-06-18 23:30:15 +0900 | [diff] [blame] | 1786 | } |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1787 | if (unlikely(!audit_dummy_context()) && (open_flag & O_CREAT)) |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1788 | audit_inode(pathname, nd.path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1789 | |
| 1790 | /* |
Al Viro | a2c36b4 | 2009-12-24 03:39:50 -0500 | [diff] [blame] | 1791 | * We have the parent and last component. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1792 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1793 | |
Al Viro | 8737f3a | 2008-08-02 22:36:57 -0400 | [diff] [blame] | 1794 | error = -ENFILE; |
| 1795 | filp = get_empty_filp(); |
| 1796 | if (filp == NULL) |
| 1797 | goto exit_parent; |
| 1798 | nd.intent.open.file = filp; |
Al Viro | 482928d | 2009-12-19 10:10:39 -0500 | [diff] [blame] | 1799 | filp->f_flags = open_flag; |
Al Viro | 8737f3a | 2008-08-02 22:36:57 -0400 | [diff] [blame] | 1800 | nd.intent.open.flags = flag; |
| 1801 | nd.intent.open.create_mode = mode; |
Christoph Hellwig | a70e65d | 2008-02-15 14:37:28 -0800 | [diff] [blame] | 1802 | nd.flags &= ~LOOKUP_PARENT; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1803 | nd.flags |= LOOKUP_OPEN; |
| 1804 | if (open_flag & O_CREAT) { |
| 1805 | nd.flags |= LOOKUP_CREATE; |
| 1806 | if (open_flag & O_EXCL) |
| 1807 | nd.flags |= LOOKUP_EXCL; |
| 1808 | } |
Al Viro | 3e297b6 | 2010-03-26 12:40:13 -0400 | [diff] [blame] | 1809 | if (open_flag & O_DIRECTORY) |
| 1810 | nd.flags |= LOOKUP_DIRECTORY; |
Jan Kara | 002baee | 2010-05-13 12:52:57 +0200 | [diff] [blame] | 1811 | if (!(open_flag & O_NOFOLLOW)) |
| 1812 | nd.flags |= LOOKUP_FOLLOW; |
Al Viro | 3e297b6 | 2010-03-26 12:40:13 -0400 | [diff] [blame] | 1813 | filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname); |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1814 | while (unlikely(!filp)) { /* trailing symlink */ |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 1815 | struct path holder; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1816 | struct inode *inode = path.dentry->d_inode; |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 1817 | void *cookie; |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1818 | error = -ELOOP; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1819 | /* S_ISDIR part is a temporary automount kludge */ |
Jan Kara | 002baee | 2010-05-13 12:52:57 +0200 | [diff] [blame] | 1820 | if (!(nd.flags & LOOKUP_FOLLOW) && !S_ISDIR(inode->i_mode)) |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 1821 | goto exit_dput; |
| 1822 | if (count++ == 32) |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1823 | goto exit_dput; |
| 1824 | /* |
| 1825 | * This is subtle. Instead of calling do_follow_link() we do |
| 1826 | * the thing by hands. The reason is that this way we have zero |
| 1827 | * link_count and path_walk() (called from ->follow_link) |
| 1828 | * honoring LOOKUP_PARENT. After that we have the parent and |
| 1829 | * last component, i.e. we are in the same situation as after |
| 1830 | * the first path_walk(). Well, almost - if the last component |
| 1831 | * is normal we get its copy stored in nd->last.name and we will |
| 1832 | * have to putname() it when we are done. Procfs-like symlinks |
| 1833 | * just set LAST_BIND. |
| 1834 | */ |
| 1835 | nd.flags |= LOOKUP_PARENT; |
| 1836 | error = security_inode_follow_link(path.dentry, &nd); |
| 1837 | if (error) |
| 1838 | goto exit_dput; |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 1839 | error = __do_follow_link(&path, &nd, &cookie); |
| 1840 | if (unlikely(error)) { |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1841 | /* nd.path had been dropped */ |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 1842 | if (!IS_ERR(cookie) && inode->i_op->put_link) |
| 1843 | inode->i_op->put_link(path.dentry, &nd, cookie); |
| 1844 | path_put(&path); |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1845 | release_open_intent(&nd); |
| 1846 | filp = ERR_PTR(error); |
| 1847 | goto out; |
| 1848 | } |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 1849 | holder = path; |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1850 | nd.flags &= ~LOOKUP_PARENT; |
Al Viro | 3e297b6 | 2010-03-26 12:40:13 -0400 | [diff] [blame] | 1851 | filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname); |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 1852 | if (inode->i_op->put_link) |
| 1853 | inode->i_op->put_link(holder.dentry, &nd, cookie); |
| 1854 | path_put(&holder); |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1855 | } |
Al Viro | 10fa8e6 | 2009-12-26 07:09:49 -0500 | [diff] [blame] | 1856 | out: |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1857 | if (nd.root.mnt) |
| 1858 | path_put(&nd.root); |
Al Viro | 10fa8e6 | 2009-12-26 07:09:49 -0500 | [diff] [blame] | 1859 | if (filp == ERR_PTR(-ESTALE) && !force_reval) { |
| 1860 | force_reval = 1; |
| 1861 | goto reval; |
| 1862 | } |
| 1863 | return filp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1864 | |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1865 | exit_dput: |
| 1866 | path_put_conditional(&path, &nd); |
| 1867 | if (!IS_ERR(nd.intent.open.file)) |
Christoph Hellwig | a70e65d | 2008-02-15 14:37:28 -0800 | [diff] [blame] | 1868 | release_open_intent(&nd); |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 1869 | exit_parent: |
| 1870 | path_put(&nd.path); |
| 1871 | filp = ERR_PTR(error); |
Al Viro | 10fa8e6 | 2009-12-26 07:09:49 -0500 | [diff] [blame] | 1872 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1873 | } |
| 1874 | |
| 1875 | /** |
Christoph Hellwig | a70e65d | 2008-02-15 14:37:28 -0800 | [diff] [blame] | 1876 | * filp_open - open file and return file pointer |
| 1877 | * |
| 1878 | * @filename: path to open |
| 1879 | * @flags: open flags as per the open(2) second argument |
| 1880 | * @mode: mode for the new file if O_CREAT is set, else ignored |
| 1881 | * |
| 1882 | * This is the helper to open a file from kernelspace if you really |
| 1883 | * have to. But in generally you should not do this, so please move |
| 1884 | * along, nothing to see here.. |
| 1885 | */ |
| 1886 | struct file *filp_open(const char *filename, int flags, int mode) |
| 1887 | { |
Al Viro | 6e8341a | 2009-04-06 11:16:22 -0400 | [diff] [blame] | 1888 | return do_filp_open(AT_FDCWD, filename, flags, mode, 0); |
Christoph Hellwig | a70e65d | 2008-02-15 14:37:28 -0800 | [diff] [blame] | 1889 | } |
| 1890 | EXPORT_SYMBOL(filp_open); |
| 1891 | |
| 1892 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1893 | * lookup_create - lookup a dentry, creating it if it doesn't exist |
| 1894 | * @nd: nameidata info |
| 1895 | * @is_dir: directory flag |
| 1896 | * |
| 1897 | * Simple function to lookup and return a dentry and create it |
| 1898 | * if it doesn't exist. Is SMP-safe. |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 1899 | * |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1900 | * Returns with nd->path.dentry->d_inode->i_mutex locked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1901 | */ |
| 1902 | struct dentry *lookup_create(struct nameidata *nd, int is_dir) |
| 1903 | { |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 1904 | struct dentry *dentry = ERR_PTR(-EEXIST); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1905 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1906 | mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 1907 | /* |
| 1908 | * Yucky last component or no last component at all? |
| 1909 | * (foo/., foo/.., /////) |
| 1910 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1911 | if (nd->last_type != LAST_NORM) |
| 1912 | goto fail; |
| 1913 | nd->flags &= ~LOOKUP_PARENT; |
Al Viro | 3516586 | 2008-08-05 03:00:49 -0400 | [diff] [blame] | 1914 | nd->flags |= LOOKUP_CREATE | LOOKUP_EXCL; |
ASANO Masahiro | a634904 | 2006-08-22 20:06:02 -0400 | [diff] [blame] | 1915 | nd->intent.open.flags = O_EXCL; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 1916 | |
| 1917 | /* |
| 1918 | * Do the final lookup. |
| 1919 | */ |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 1920 | dentry = lookup_hash(nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1921 | if (IS_ERR(dentry)) |
| 1922 | goto fail; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 1923 | |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 1924 | if (dentry->d_inode) |
| 1925 | goto eexist; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 1926 | /* |
| 1927 | * Special case - lookup gave negative, but... we had foo/bar/ |
| 1928 | * From the vfs_mknod() POV we just have a negative dentry - |
| 1929 | * all is fine. Let's be bastards - you had / on the end, you've |
| 1930 | * been asking for (non-existent) directory. -ENOENT for you. |
| 1931 | */ |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 1932 | if (unlikely(!is_dir && nd->last.name[nd->last.len])) { |
| 1933 | dput(dentry); |
| 1934 | dentry = ERR_PTR(-ENOENT); |
| 1935 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1936 | return dentry; |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 1937 | eexist: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1938 | dput(dentry); |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 1939 | dentry = ERR_PTR(-EEXIST); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1940 | fail: |
| 1941 | return dentry; |
| 1942 | } |
Christoph Hellwig | f81a0bf | 2005-05-19 12:26:43 -0700 | [diff] [blame] | 1943 | EXPORT_SYMBOL_GPL(lookup_create); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1944 | |
| 1945 | int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) |
| 1946 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 1947 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1948 | |
| 1949 | if (error) |
| 1950 | return error; |
| 1951 | |
| 1952 | if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) |
| 1953 | return -EPERM; |
| 1954 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 1955 | if (!dir->i_op->mknod) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1956 | return -EPERM; |
| 1957 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 1958 | error = devcgroup_inode_mknod(mode, dev); |
| 1959 | if (error) |
| 1960 | return error; |
| 1961 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1962 | error = security_inode_mknod(dir, dentry, mode, dev); |
| 1963 | if (error) |
| 1964 | return error; |
| 1965 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1966 | error = dir->i_op->mknod(dir, dentry, mode, dev); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 1967 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 1968 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1969 | return error; |
| 1970 | } |
| 1971 | |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 1972 | static int may_mknod(mode_t mode) |
| 1973 | { |
| 1974 | switch (mode & S_IFMT) { |
| 1975 | case S_IFREG: |
| 1976 | case S_IFCHR: |
| 1977 | case S_IFBLK: |
| 1978 | case S_IFIFO: |
| 1979 | case S_IFSOCK: |
| 1980 | case 0: /* zero mode translates to S_IFREG */ |
| 1981 | return 0; |
| 1982 | case S_IFDIR: |
| 1983 | return -EPERM; |
| 1984 | default: |
| 1985 | return -EINVAL; |
| 1986 | } |
| 1987 | } |
| 1988 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 1989 | SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, int, mode, |
| 1990 | unsigned, dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1991 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 1992 | int error; |
| 1993 | char *tmp; |
| 1994 | struct dentry *dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1995 | struct nameidata nd; |
| 1996 | |
| 1997 | if (S_ISDIR(mode)) |
| 1998 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1999 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2000 | error = user_path_parent(dfd, filename, &nd, &tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2001 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2002 | return error; |
| 2003 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2004 | dentry = lookup_create(&nd, 0); |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2005 | if (IS_ERR(dentry)) { |
| 2006 | error = PTR_ERR(dentry); |
| 2007 | goto out_unlock; |
| 2008 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2009 | if (!IS_POSIXACL(nd.path.dentry->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 2010 | mode &= ~current_umask(); |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2011 | error = may_mknod(mode); |
| 2012 | if (error) |
| 2013 | goto out_dput; |
| 2014 | error = mnt_want_write(nd.path.mnt); |
| 2015 | if (error) |
| 2016 | goto out_dput; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2017 | error = security_path_mknod(&nd.path, dentry, mode, dev); |
| 2018 | if (error) |
| 2019 | goto out_drop_write; |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2020 | switch (mode & S_IFMT) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2021 | case 0: case S_IFREG: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2022 | error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2023 | break; |
| 2024 | case S_IFCHR: case S_IFBLK: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2025 | error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2026 | new_decode_dev(dev)); |
| 2027 | break; |
| 2028 | case S_IFIFO: case S_IFSOCK: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2029 | error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2030 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2031 | } |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2032 | out_drop_write: |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2033 | mnt_drop_write(nd.path.mnt); |
| 2034 | out_dput: |
| 2035 | dput(dentry); |
| 2036 | out_unlock: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2037 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2038 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2039 | putname(tmp); |
| 2040 | |
| 2041 | return error; |
| 2042 | } |
| 2043 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 2044 | SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2045 | { |
| 2046 | return sys_mknodat(AT_FDCWD, filename, mode, dev); |
| 2047 | } |
| 2048 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2049 | int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
| 2050 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2051 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2052 | |
| 2053 | if (error) |
| 2054 | return error; |
| 2055 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2056 | if (!dir->i_op->mkdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2057 | return -EPERM; |
| 2058 | |
| 2059 | mode &= (S_IRWXUGO|S_ISVTX); |
| 2060 | error = security_inode_mkdir(dir, dentry, mode); |
| 2061 | if (error) |
| 2062 | return error; |
| 2063 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2064 | error = dir->i_op->mkdir(dir, dentry, mode); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 2065 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 2066 | fsnotify_mkdir(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2067 | return error; |
| 2068 | } |
| 2069 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 2070 | SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, int, mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2071 | { |
| 2072 | int error = 0; |
| 2073 | char * tmp; |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2074 | struct dentry *dentry; |
| 2075 | struct nameidata nd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2076 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2077 | error = user_path_parent(dfd, pathname, &nd, &tmp); |
| 2078 | if (error) |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2079 | goto out_err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2080 | |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2081 | dentry = lookup_create(&nd, 1); |
| 2082 | error = PTR_ERR(dentry); |
| 2083 | if (IS_ERR(dentry)) |
| 2084 | goto out_unlock; |
| 2085 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2086 | if (!IS_POSIXACL(nd.path.dentry->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 2087 | mode &= ~current_umask(); |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2088 | error = mnt_want_write(nd.path.mnt); |
| 2089 | if (error) |
| 2090 | goto out_dput; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2091 | error = security_path_mkdir(&nd.path, dentry, mode); |
| 2092 | if (error) |
| 2093 | goto out_drop_write; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2094 | error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2095 | out_drop_write: |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 2096 | mnt_drop_write(nd.path.mnt); |
| 2097 | out_dput: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2098 | dput(dentry); |
| 2099 | out_unlock: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2100 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2101 | path_put(&nd.path); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2102 | putname(tmp); |
| 2103 | out_err: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2104 | return error; |
| 2105 | } |
| 2106 | |
Heiko Carstens | 3cdad42 | 2009-01-14 14:14:22 +0100 | [diff] [blame] | 2107 | SYSCALL_DEFINE2(mkdir, const char __user *, pathname, int, mode) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2108 | { |
| 2109 | return sys_mkdirat(AT_FDCWD, pathname, mode); |
| 2110 | } |
| 2111 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2112 | /* |
| 2113 | * We try to drop the dentry early: we should have |
| 2114 | * a usage count of 2 if we're the only user of this |
| 2115 | * dentry, and if that is true (possibly after pruning |
| 2116 | * the dcache), then we drop the dentry now. |
| 2117 | * |
| 2118 | * A low-level filesystem can, if it choses, legally |
| 2119 | * do a |
| 2120 | * |
| 2121 | * if (!d_unhashed(dentry)) |
| 2122 | * return -EBUSY; |
| 2123 | * |
| 2124 | * if it cannot handle the case of removing a directory |
| 2125 | * that is still in use by something else.. |
| 2126 | */ |
| 2127 | void dentry_unhash(struct dentry *dentry) |
| 2128 | { |
| 2129 | dget(dentry); |
Vasily Averin | dc16842 | 2006-12-06 20:37:07 -0800 | [diff] [blame] | 2130 | shrink_dcache_parent(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2131 | spin_lock(&dentry->d_lock); |
Nick Piggin | b7ab39f | 2011-01-07 17:49:32 +1100 | [diff] [blame] | 2132 | if (dentry->d_count == 2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2133 | __d_drop(dentry); |
| 2134 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2135 | } |
| 2136 | |
| 2137 | int vfs_rmdir(struct inode *dir, struct dentry *dentry) |
| 2138 | { |
| 2139 | int error = may_delete(dir, dentry, 1); |
| 2140 | |
| 2141 | if (error) |
| 2142 | return error; |
| 2143 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2144 | if (!dir->i_op->rmdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2145 | return -EPERM; |
| 2146 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2147 | mutex_lock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2148 | dentry_unhash(dentry); |
| 2149 | if (d_mountpoint(dentry)) |
| 2150 | error = -EBUSY; |
| 2151 | else { |
| 2152 | error = security_inode_rmdir(dir, dentry); |
| 2153 | if (!error) { |
| 2154 | error = dir->i_op->rmdir(dir, dentry); |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2155 | if (!error) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2156 | dentry->d_inode->i_flags |= S_DEAD; |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2157 | dont_mount(dentry); |
| 2158 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2159 | } |
| 2160 | } |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2161 | mutex_unlock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2162 | if (!error) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2163 | d_delete(dentry); |
| 2164 | } |
| 2165 | dput(dentry); |
| 2166 | |
| 2167 | return error; |
| 2168 | } |
| 2169 | |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2170 | static long do_rmdir(int dfd, const char __user *pathname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2171 | { |
| 2172 | int error = 0; |
| 2173 | char * name; |
| 2174 | struct dentry *dentry; |
| 2175 | struct nameidata nd; |
| 2176 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2177 | error = user_path_parent(dfd, pathname, &nd, &name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2178 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2179 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2180 | |
| 2181 | switch(nd.last_type) { |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2182 | case LAST_DOTDOT: |
| 2183 | error = -ENOTEMPTY; |
| 2184 | goto exit1; |
| 2185 | case LAST_DOT: |
| 2186 | error = -EINVAL; |
| 2187 | goto exit1; |
| 2188 | case LAST_ROOT: |
| 2189 | error = -EBUSY; |
| 2190 | goto exit1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2191 | } |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2192 | |
| 2193 | nd.flags &= ~LOOKUP_PARENT; |
| 2194 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2195 | 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] | 2196 | dentry = lookup_hash(&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2197 | error = PTR_ERR(dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2198 | if (IS_ERR(dentry)) |
| 2199 | goto exit2; |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 2200 | error = mnt_want_write(nd.path.mnt); |
| 2201 | if (error) |
| 2202 | goto exit3; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2203 | error = security_path_rmdir(&nd.path, dentry); |
| 2204 | if (error) |
| 2205 | goto exit4; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2206 | error = vfs_rmdir(nd.path.dentry->d_inode, dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2207 | exit4: |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 2208 | mnt_drop_write(nd.path.mnt); |
| 2209 | exit3: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2210 | dput(dentry); |
| 2211 | exit2: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2212 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2213 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2214 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2215 | putname(name); |
| 2216 | return error; |
| 2217 | } |
| 2218 | |
Heiko Carstens | 3cdad42 | 2009-01-14 14:14:22 +0100 | [diff] [blame] | 2219 | SYSCALL_DEFINE1(rmdir, const char __user *, pathname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2220 | { |
| 2221 | return do_rmdir(AT_FDCWD, pathname); |
| 2222 | } |
| 2223 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2224 | int vfs_unlink(struct inode *dir, struct dentry *dentry) |
| 2225 | { |
| 2226 | int error = may_delete(dir, dentry, 0); |
| 2227 | |
| 2228 | if (error) |
| 2229 | return error; |
| 2230 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2231 | if (!dir->i_op->unlink) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2232 | return -EPERM; |
| 2233 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2234 | mutex_lock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2235 | if (d_mountpoint(dentry)) |
| 2236 | error = -EBUSY; |
| 2237 | else { |
| 2238 | error = security_inode_unlink(dir, dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 2239 | if (!error) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2240 | error = dir->i_op->unlink(dir, dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 2241 | if (!error) |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2242 | dont_mount(dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 2243 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2244 | } |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2245 | mutex_unlock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2246 | |
| 2247 | /* We don't d_delete() NFS sillyrenamed files--they still exist. */ |
| 2248 | if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { |
Jan Kara | ece9591 | 2008-02-06 01:37:13 -0800 | [diff] [blame] | 2249 | fsnotify_link_count(dentry->d_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2250 | d_delete(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2251 | } |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 2252 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2253 | return error; |
| 2254 | } |
| 2255 | |
| 2256 | /* |
| 2257 | * 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] | 2258 | * 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] | 2259 | * writeout happening, and we don't want to prevent access to the directory |
| 2260 | * while waiting on the I/O. |
| 2261 | */ |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2262 | static long do_unlinkat(int dfd, const char __user *pathname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2263 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2264 | int error; |
| 2265 | char *name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2266 | struct dentry *dentry; |
| 2267 | struct nameidata nd; |
| 2268 | struct inode *inode = NULL; |
| 2269 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2270 | error = user_path_parent(dfd, pathname, &nd, &name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2271 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2272 | return error; |
| 2273 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2274 | error = -EISDIR; |
| 2275 | if (nd.last_type != LAST_NORM) |
| 2276 | goto exit1; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2277 | |
| 2278 | nd.flags &= ~LOOKUP_PARENT; |
| 2279 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2280 | 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] | 2281 | dentry = lookup_hash(&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2282 | error = PTR_ERR(dentry); |
| 2283 | if (!IS_ERR(dentry)) { |
| 2284 | /* Why not before? Because we want correct error value */ |
| 2285 | if (nd.last.name[nd.last.len]) |
| 2286 | goto slashes; |
| 2287 | inode = dentry->d_inode; |
| 2288 | if (inode) |
Al Viro | 7de9c6e | 2010-10-23 11:11:40 -0400 | [diff] [blame] | 2289 | ihold(inode); |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 2290 | error = mnt_want_write(nd.path.mnt); |
| 2291 | if (error) |
| 2292 | goto exit2; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2293 | error = security_path_unlink(&nd.path, dentry); |
| 2294 | if (error) |
| 2295 | goto exit3; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2296 | error = vfs_unlink(nd.path.dentry->d_inode, dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2297 | exit3: |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 2298 | mnt_drop_write(nd.path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2299 | exit2: |
| 2300 | dput(dentry); |
| 2301 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2302 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2303 | if (inode) |
| 2304 | iput(inode); /* truncate the inode here */ |
| 2305 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2306 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2307 | putname(name); |
| 2308 | return error; |
| 2309 | |
| 2310 | slashes: |
| 2311 | error = !dentry->d_inode ? -ENOENT : |
| 2312 | S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; |
| 2313 | goto exit2; |
| 2314 | } |
| 2315 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 2316 | SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2317 | { |
| 2318 | if ((flag & ~AT_REMOVEDIR) != 0) |
| 2319 | return -EINVAL; |
| 2320 | |
| 2321 | if (flag & AT_REMOVEDIR) |
| 2322 | return do_rmdir(dfd, pathname); |
| 2323 | |
| 2324 | return do_unlinkat(dfd, pathname); |
| 2325 | } |
| 2326 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 2327 | SYSCALL_DEFINE1(unlink, const char __user *, pathname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2328 | { |
| 2329 | return do_unlinkat(AT_FDCWD, pathname); |
| 2330 | } |
| 2331 | |
Miklos Szeredi | db2e747 | 2008-06-24 16:50:16 +0200 | [diff] [blame] | 2332 | int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2333 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2334 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2335 | |
| 2336 | if (error) |
| 2337 | return error; |
| 2338 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2339 | if (!dir->i_op->symlink) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2340 | return -EPERM; |
| 2341 | |
| 2342 | error = security_inode_symlink(dir, dentry, oldname); |
| 2343 | if (error) |
| 2344 | return error; |
| 2345 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2346 | error = dir->i_op->symlink(dir, dentry, oldname); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 2347 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 2348 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2349 | return error; |
| 2350 | } |
| 2351 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 2352 | SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, |
| 2353 | int, newdfd, const char __user *, newname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2354 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2355 | int error; |
| 2356 | char *from; |
| 2357 | char *to; |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2358 | struct dentry *dentry; |
| 2359 | struct nameidata nd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2360 | |
| 2361 | from = getname(oldname); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2362 | if (IS_ERR(from)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2363 | return PTR_ERR(from); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2364 | |
| 2365 | error = user_path_parent(newdfd, newname, &nd, &to); |
| 2366 | if (error) |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2367 | goto out_putname; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2368 | |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2369 | dentry = lookup_create(&nd, 0); |
| 2370 | error = PTR_ERR(dentry); |
| 2371 | if (IS_ERR(dentry)) |
| 2372 | goto out_unlock; |
| 2373 | |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 2374 | error = mnt_want_write(nd.path.mnt); |
| 2375 | if (error) |
| 2376 | goto out_dput; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2377 | error = security_path_symlink(&nd.path, dentry, from); |
| 2378 | if (error) |
| 2379 | goto out_drop_write; |
Miklos Szeredi | db2e747 | 2008-06-24 16:50:16 +0200 | [diff] [blame] | 2380 | error = vfs_symlink(nd.path.dentry->d_inode, dentry, from); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2381 | out_drop_write: |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 2382 | mnt_drop_write(nd.path.mnt); |
| 2383 | out_dput: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2384 | dput(dentry); |
| 2385 | out_unlock: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2386 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2387 | path_put(&nd.path); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2388 | putname(to); |
| 2389 | out_putname: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2390 | putname(from); |
| 2391 | return error; |
| 2392 | } |
| 2393 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 2394 | SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2395 | { |
| 2396 | return sys_symlinkat(oldname, AT_FDCWD, newname); |
| 2397 | } |
| 2398 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2399 | int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) |
| 2400 | { |
| 2401 | struct inode *inode = old_dentry->d_inode; |
| 2402 | int error; |
| 2403 | |
| 2404 | if (!inode) |
| 2405 | return -ENOENT; |
| 2406 | |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2407 | error = may_create(dir, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2408 | if (error) |
| 2409 | return error; |
| 2410 | |
| 2411 | if (dir->i_sb != inode->i_sb) |
| 2412 | return -EXDEV; |
| 2413 | |
| 2414 | /* |
| 2415 | * A link to an append-only or immutable file cannot be created. |
| 2416 | */ |
| 2417 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) |
| 2418 | return -EPERM; |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2419 | if (!dir->i_op->link) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2420 | return -EPERM; |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 2421 | if (S_ISDIR(inode->i_mode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2422 | return -EPERM; |
| 2423 | |
| 2424 | error = security_inode_link(old_dentry, dir, new_dentry); |
| 2425 | if (error) |
| 2426 | return error; |
| 2427 | |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 2428 | mutex_lock(&inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2429 | error = dir->i_op->link(old_dentry, dir, new_dentry); |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 2430 | mutex_unlock(&inode->i_mutex); |
Stephen Smalley | e31e14e | 2005-09-09 13:01:45 -0700 | [diff] [blame] | 2431 | if (!error) |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 2432 | fsnotify_link(dir, inode, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2433 | return error; |
| 2434 | } |
| 2435 | |
| 2436 | /* |
| 2437 | * Hardlinks are often used in delicate situations. We avoid |
| 2438 | * security-related surprises by not following symlinks on the |
| 2439 | * newname. --KAB |
| 2440 | * |
| 2441 | * We don't follow them on the oldname either to be compatible |
| 2442 | * with linux 2.0, and to avoid hard-linking to directories |
| 2443 | * and other special files. --ADM |
| 2444 | */ |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 2445 | SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, |
| 2446 | int, newdfd, const char __user *, newname, int, flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2447 | { |
| 2448 | struct dentry *new_dentry; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2449 | struct nameidata nd; |
| 2450 | struct path old_path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2451 | int error; |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2452 | char *to; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2453 | |
Ulrich Drepper | 45c9b11 | 2006-06-25 05:49:11 -0700 | [diff] [blame] | 2454 | if ((flags & ~AT_SYMLINK_FOLLOW) != 0) |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 2455 | return -EINVAL; |
| 2456 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2457 | error = user_path_at(olddfd, oldname, |
| 2458 | flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, |
| 2459 | &old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2460 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2461 | return error; |
| 2462 | |
| 2463 | error = user_path_parent(newdfd, newname, &nd, &to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2464 | if (error) |
| 2465 | goto out; |
| 2466 | error = -EXDEV; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2467 | if (old_path.mnt != nd.path.mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2468 | goto out_release; |
| 2469 | new_dentry = lookup_create(&nd, 0); |
| 2470 | error = PTR_ERR(new_dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2471 | if (IS_ERR(new_dentry)) |
| 2472 | goto out_unlock; |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 2473 | error = mnt_want_write(nd.path.mnt); |
| 2474 | if (error) |
| 2475 | goto out_dput; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2476 | error = security_path_link(old_path.dentry, &nd.path, new_dentry); |
| 2477 | if (error) |
| 2478 | goto out_drop_write; |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2479 | error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2480 | out_drop_write: |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 2481 | mnt_drop_write(nd.path.mnt); |
| 2482 | out_dput: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 2483 | dput(new_dentry); |
| 2484 | out_unlock: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2485 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2486 | out_release: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2487 | path_put(&nd.path); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2488 | putname(to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2489 | out: |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2490 | path_put(&old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2491 | |
| 2492 | return error; |
| 2493 | } |
| 2494 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 2495 | SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2496 | { |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 2497 | return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2498 | } |
| 2499 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2500 | /* |
| 2501 | * The worst of all namespace operations - renaming directory. "Perverted" |
| 2502 | * doesn't even start to describe it. Somebody in UCB had a heck of a trip... |
| 2503 | * Problems: |
| 2504 | * a) we can get into loop creation. Check is done in is_subdir(). |
| 2505 | * b) race potential - two innocent renames can create a loop together. |
| 2506 | * 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] | 2507 | * 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] | 2508 | * story. |
| 2509 | * 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] | 2510 | * 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] | 2511 | * whether the target exists). Solution: try to be smart with locking |
| 2512 | * 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] | 2513 | * 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] | 2514 | * move will be locked. Thus we can rank directories by the tree |
| 2515 | * (ancestors first) and rank all non-directories after them. |
| 2516 | * That works since everybody except rename does "lock parent, lookup, |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 2517 | * lock child" and rename is under ->s_vfs_rename_mutex. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2518 | * HOWEVER, it relies on the assumption that any object with ->lookup() |
| 2519 | * has no more than 1 dentry. If "hybrid" objects will ever appear, |
| 2520 | * we'd better make sure that there's no link(2) for them. |
| 2521 | * d) some filesystems don't support opened-but-unlinked directories, |
| 2522 | * either because of layout or because they are not ready to deal with |
| 2523 | * all cases correctly. The latter will be fixed (taking this sort of |
| 2524 | * stuff into VFS), but the former is not going away. Solution: the same |
| 2525 | * trick as in rmdir(). |
| 2526 | * e) conversion from fhandle to dentry may come in the wrong moment - when |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2527 | * 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] | 2528 | * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on |
Adam Buchbinder | c41b20e | 2009-12-11 16:35:39 -0500 | [diff] [blame] | 2529 | * ->i_mutex on parents, which works but leads to some truly excessive |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2530 | * locking]. |
| 2531 | */ |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 2532 | static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, |
| 2533 | struct inode *new_dir, struct dentry *new_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2534 | { |
| 2535 | int error = 0; |
| 2536 | struct inode *target; |
| 2537 | |
| 2538 | /* |
| 2539 | * If we are going to change the parent - check write permissions, |
| 2540 | * we'll need to flip '..'. |
| 2541 | */ |
| 2542 | if (new_dir != old_dir) { |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 2543 | error = inode_permission(old_dentry->d_inode, MAY_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2544 | if (error) |
| 2545 | return error; |
| 2546 | } |
| 2547 | |
| 2548 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); |
| 2549 | if (error) |
| 2550 | return error; |
| 2551 | |
| 2552 | target = new_dentry->d_inode; |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2553 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2554 | mutex_lock(&target->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2555 | if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) |
| 2556 | error = -EBUSY; |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2557 | else { |
| 2558 | if (target) |
| 2559 | dentry_unhash(new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2560 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2561 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2562 | if (target) { |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2563 | if (!error) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2564 | target->i_flags |= S_DEAD; |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2565 | dont_mount(new_dentry); |
| 2566 | } |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2567 | mutex_unlock(&target->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2568 | if (d_unhashed(new_dentry)) |
| 2569 | d_rehash(new_dentry); |
| 2570 | dput(new_dentry); |
| 2571 | } |
Stephen Smalley | e31e14e | 2005-09-09 13:01:45 -0700 | [diff] [blame] | 2572 | if (!error) |
Mark Fasheh | 349457c | 2006-09-08 14:22:21 -0700 | [diff] [blame] | 2573 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
| 2574 | d_move(old_dentry,new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2575 | return error; |
| 2576 | } |
| 2577 | |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 2578 | static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, |
| 2579 | struct inode *new_dir, struct dentry *new_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2580 | { |
| 2581 | struct inode *target; |
| 2582 | int error; |
| 2583 | |
| 2584 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); |
| 2585 | if (error) |
| 2586 | return error; |
| 2587 | |
| 2588 | dget(new_dentry); |
| 2589 | target = new_dentry->d_inode; |
| 2590 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2591 | mutex_lock(&target->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2592 | if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) |
| 2593 | error = -EBUSY; |
| 2594 | else |
| 2595 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); |
| 2596 | if (!error) { |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 2597 | if (target) |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 2598 | dont_mount(new_dentry); |
Mark Fasheh | 349457c | 2006-09-08 14:22:21 -0700 | [diff] [blame] | 2599 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2600 | d_move(old_dentry, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2601 | } |
| 2602 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2603 | mutex_unlock(&target->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2604 | dput(new_dentry); |
| 2605 | return error; |
| 2606 | } |
| 2607 | |
| 2608 | int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, |
| 2609 | struct inode *new_dir, struct dentry *new_dentry) |
| 2610 | { |
| 2611 | int error; |
| 2612 | int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); |
Eric Paris | 59b0df2 | 2010-02-08 12:53:52 -0500 | [diff] [blame] | 2613 | const unsigned char *old_name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2614 | |
| 2615 | if (old_dentry->d_inode == new_dentry->d_inode) |
| 2616 | return 0; |
| 2617 | |
| 2618 | error = may_delete(old_dir, old_dentry, is_dir); |
| 2619 | if (error) |
| 2620 | return error; |
| 2621 | |
| 2622 | if (!new_dentry->d_inode) |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2623 | error = may_create(new_dir, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2624 | else |
| 2625 | error = may_delete(new_dir, new_dentry, is_dir); |
| 2626 | if (error) |
| 2627 | return error; |
| 2628 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2629 | if (!old_dir->i_op->rename) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2630 | return -EPERM; |
| 2631 | |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 2632 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); |
| 2633 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2634 | if (is_dir) |
| 2635 | error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); |
| 2636 | else |
| 2637 | error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); |
Al Viro | 123df29 | 2009-12-25 04:57:57 -0500 | [diff] [blame] | 2638 | if (!error) |
| 2639 | fsnotify_move(old_dir, new_dir, old_name, is_dir, |
Al Viro | 5a190ae | 2007-06-07 12:19:32 -0400 | [diff] [blame] | 2640 | new_dentry->d_inode, old_dentry); |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 2641 | fsnotify_oldname_free(old_name); |
| 2642 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2643 | return error; |
| 2644 | } |
| 2645 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 2646 | SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, |
| 2647 | int, newdfd, const char __user *, newname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2648 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2649 | struct dentry *old_dir, *new_dir; |
| 2650 | struct dentry *old_dentry, *new_dentry; |
| 2651 | struct dentry *trap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2652 | struct nameidata oldnd, newnd; |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2653 | char *from; |
| 2654 | char *to; |
| 2655 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2656 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2657 | error = user_path_parent(olddfd, oldname, &oldnd, &from); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2658 | if (error) |
| 2659 | goto exit; |
| 2660 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2661 | error = user_path_parent(newdfd, newname, &newnd, &to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2662 | if (error) |
| 2663 | goto exit1; |
| 2664 | |
| 2665 | error = -EXDEV; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2666 | if (oldnd.path.mnt != newnd.path.mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2667 | goto exit2; |
| 2668 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2669 | old_dir = oldnd.path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2670 | error = -EBUSY; |
| 2671 | if (oldnd.last_type != LAST_NORM) |
| 2672 | goto exit2; |
| 2673 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 2674 | new_dir = newnd.path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2675 | if (newnd.last_type != LAST_NORM) |
| 2676 | goto exit2; |
| 2677 | |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2678 | oldnd.flags &= ~LOOKUP_PARENT; |
| 2679 | newnd.flags &= ~LOOKUP_PARENT; |
OGAWA Hirofumi | 4e9ed2f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2680 | newnd.flags |= LOOKUP_RENAME_TARGET; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 2681 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2682 | trap = lock_rename(new_dir, old_dir); |
| 2683 | |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 2684 | old_dentry = lookup_hash(&oldnd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2685 | error = PTR_ERR(old_dentry); |
| 2686 | if (IS_ERR(old_dentry)) |
| 2687 | goto exit3; |
| 2688 | /* source must exist */ |
| 2689 | error = -ENOENT; |
| 2690 | if (!old_dentry->d_inode) |
| 2691 | goto exit4; |
| 2692 | /* unless the source is a directory trailing slashes give -ENOTDIR */ |
| 2693 | if (!S_ISDIR(old_dentry->d_inode->i_mode)) { |
| 2694 | error = -ENOTDIR; |
| 2695 | if (oldnd.last.name[oldnd.last.len]) |
| 2696 | goto exit4; |
| 2697 | if (newnd.last.name[newnd.last.len]) |
| 2698 | goto exit4; |
| 2699 | } |
| 2700 | /* source should not be ancestor of target */ |
| 2701 | error = -EINVAL; |
| 2702 | if (old_dentry == trap) |
| 2703 | goto exit4; |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 2704 | new_dentry = lookup_hash(&newnd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2705 | error = PTR_ERR(new_dentry); |
| 2706 | if (IS_ERR(new_dentry)) |
| 2707 | goto exit4; |
| 2708 | /* target should not be an ancestor of source */ |
| 2709 | error = -ENOTEMPTY; |
| 2710 | if (new_dentry == trap) |
| 2711 | goto exit5; |
| 2712 | |
Dave Hansen | 9079b1e | 2008-02-15 14:37:49 -0800 | [diff] [blame] | 2713 | error = mnt_want_write(oldnd.path.mnt); |
| 2714 | if (error) |
| 2715 | goto exit5; |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2716 | error = security_path_rename(&oldnd.path, old_dentry, |
| 2717 | &newnd.path, new_dentry); |
| 2718 | if (error) |
| 2719 | goto exit6; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2720 | error = vfs_rename(old_dir->d_inode, old_dentry, |
| 2721 | new_dir->d_inode, new_dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 2722 | exit6: |
Dave Hansen | 9079b1e | 2008-02-15 14:37:49 -0800 | [diff] [blame] | 2723 | mnt_drop_write(oldnd.path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2724 | exit5: |
| 2725 | dput(new_dentry); |
| 2726 | exit4: |
| 2727 | dput(old_dentry); |
| 2728 | exit3: |
| 2729 | unlock_rename(new_dir, old_dir); |
| 2730 | exit2: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2731 | path_put(&newnd.path); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2732 | putname(to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2733 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 2734 | path_put(&oldnd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2735 | putname(from); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2736 | exit: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2737 | return error; |
| 2738 | } |
| 2739 | |
Heiko Carstens | a26eab2 | 2009-01-14 14:14:17 +0100 | [diff] [blame] | 2740 | SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2741 | { |
| 2742 | return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); |
| 2743 | } |
| 2744 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2745 | int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) |
| 2746 | { |
| 2747 | int len; |
| 2748 | |
| 2749 | len = PTR_ERR(link); |
| 2750 | if (IS_ERR(link)) |
| 2751 | goto out; |
| 2752 | |
| 2753 | len = strlen(link); |
| 2754 | if (len > (unsigned) buflen) |
| 2755 | len = buflen; |
| 2756 | if (copy_to_user(buffer, link, len)) |
| 2757 | len = -EFAULT; |
| 2758 | out: |
| 2759 | return len; |
| 2760 | } |
| 2761 | |
| 2762 | /* |
| 2763 | * A helper for ->readlink(). This should be used *ONLY* for symlinks that |
| 2764 | * have ->follow_link() touching nd only in nd_set_link(). Using (or not |
| 2765 | * using) it for any given inode is up to filesystem. |
| 2766 | */ |
| 2767 | int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 2768 | { |
| 2769 | struct nameidata nd; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 2770 | void *cookie; |
Marcin Slusarz | 694a176 | 2008-06-09 16:40:37 -0700 | [diff] [blame] | 2771 | int res; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 2772 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2773 | nd.depth = 0; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 2774 | cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); |
Marcin Slusarz | 694a176 | 2008-06-09 16:40:37 -0700 | [diff] [blame] | 2775 | if (IS_ERR(cookie)) |
| 2776 | return PTR_ERR(cookie); |
| 2777 | |
| 2778 | res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); |
| 2779 | if (dentry->d_inode->i_op->put_link) |
| 2780 | dentry->d_inode->i_op->put_link(dentry, &nd, cookie); |
| 2781 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2782 | } |
| 2783 | |
| 2784 | int vfs_follow_link(struct nameidata *nd, const char *link) |
| 2785 | { |
| 2786 | return __vfs_follow_link(nd, link); |
| 2787 | } |
| 2788 | |
| 2789 | /* get the link contents into pagecache */ |
| 2790 | static char *page_getlink(struct dentry * dentry, struct page **ppage) |
| 2791 | { |
Duane Griffin | ebd09ab | 2008-12-19 20:47:12 +0000 | [diff] [blame] | 2792 | char *kaddr; |
| 2793 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2794 | struct address_space *mapping = dentry->d_inode->i_mapping; |
Pekka Enberg | 090d2b1 | 2006-06-23 02:05:08 -0700 | [diff] [blame] | 2795 | page = read_mapping_page(mapping, 0, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2796 | if (IS_ERR(page)) |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 2797 | return (char*)page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2798 | *ppage = page; |
Duane Griffin | ebd09ab | 2008-12-19 20:47:12 +0000 | [diff] [blame] | 2799 | kaddr = kmap(page); |
| 2800 | nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); |
| 2801 | return kaddr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2802 | } |
| 2803 | |
| 2804 | int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 2805 | { |
| 2806 | struct page *page = NULL; |
| 2807 | char *s = page_getlink(dentry, &page); |
| 2808 | int res = vfs_readlink(dentry,buffer,buflen,s); |
| 2809 | if (page) { |
| 2810 | kunmap(page); |
| 2811 | page_cache_release(page); |
| 2812 | } |
| 2813 | return res; |
| 2814 | } |
| 2815 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 2816 | void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2817 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 2818 | struct page *page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2819 | nd_set_link(nd, page_getlink(dentry, &page)); |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 2820 | return page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2821 | } |
| 2822 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 2823 | void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2824 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 2825 | struct page *page = cookie; |
| 2826 | |
| 2827 | if (page) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2828 | kunmap(page); |
| 2829 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2830 | } |
| 2831 | } |
| 2832 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2833 | /* |
| 2834 | * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS |
| 2835 | */ |
| 2836 | 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] | 2837 | { |
| 2838 | struct address_space *mapping = inode->i_mapping; |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 2839 | struct page *page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2840 | void *fsdata; |
Dmitriy Monakhov | beb497a | 2007-02-16 01:27:18 -0800 | [diff] [blame] | 2841 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2842 | char *kaddr; |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2843 | unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; |
| 2844 | if (nofs) |
| 2845 | flags |= AOP_FLAG_NOFS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2846 | |
NeilBrown | 7e53cac | 2006-03-25 03:07:57 -0800 | [diff] [blame] | 2847 | retry: |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2848 | err = pagecache_write_begin(NULL, mapping, 0, len-1, |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2849 | flags, &page, &fsdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2850 | if (err) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2851 | goto fail; |
| 2852 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2853 | kaddr = kmap_atomic(page, KM_USER0); |
| 2854 | memcpy(kaddr, symname, len-1); |
| 2855 | kunmap_atomic(kaddr, KM_USER0); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2856 | |
| 2857 | err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, |
| 2858 | page, fsdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2859 | if (err < 0) |
| 2860 | goto fail; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 2861 | if (err < len-1) |
| 2862 | goto retry; |
| 2863 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2864 | mark_inode_dirty(inode); |
| 2865 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2866 | fail: |
| 2867 | return err; |
| 2868 | } |
| 2869 | |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 2870 | int page_symlink(struct inode *inode, const char *symname, int len) |
| 2871 | { |
| 2872 | return __page_symlink(inode, symname, len, |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 2873 | !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS)); |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 2874 | } |
| 2875 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 2876 | const struct inode_operations page_symlink_inode_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2877 | .readlink = generic_readlink, |
| 2878 | .follow_link = page_follow_link_light, |
| 2879 | .put_link = page_put_link, |
| 2880 | }; |
| 2881 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2882 | EXPORT_SYMBOL(user_path_at); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2883 | EXPORT_SYMBOL(follow_down); |
| 2884 | EXPORT_SYMBOL(follow_up); |
| 2885 | EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ |
| 2886 | EXPORT_SYMBOL(getname); |
| 2887 | EXPORT_SYMBOL(lock_rename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2888 | EXPORT_SYMBOL(lookup_one_len); |
| 2889 | EXPORT_SYMBOL(page_follow_link_light); |
| 2890 | EXPORT_SYMBOL(page_put_link); |
| 2891 | EXPORT_SYMBOL(page_readlink); |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 2892 | EXPORT_SYMBOL(__page_symlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2893 | EXPORT_SYMBOL(page_symlink); |
| 2894 | EXPORT_SYMBOL(page_symlink_inode_operations); |
| 2895 | EXPORT_SYMBOL(path_lookup); |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 2896 | EXPORT_SYMBOL(kern_path); |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2897 | EXPORT_SYMBOL(vfs_path_lookup); |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 2898 | EXPORT_SYMBOL(inode_permission); |
Christoph Hellwig | 8c744fb | 2005-11-08 21:35:04 -0800 | [diff] [blame] | 2899 | EXPORT_SYMBOL(file_permission); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2900 | EXPORT_SYMBOL(unlock_rename); |
| 2901 | EXPORT_SYMBOL(vfs_create); |
| 2902 | EXPORT_SYMBOL(vfs_follow_link); |
| 2903 | EXPORT_SYMBOL(vfs_link); |
| 2904 | EXPORT_SYMBOL(vfs_mkdir); |
| 2905 | EXPORT_SYMBOL(vfs_mknod); |
| 2906 | EXPORT_SYMBOL(generic_permission); |
| 2907 | EXPORT_SYMBOL(vfs_readlink); |
| 2908 | EXPORT_SYMBOL(vfs_rename); |
| 2909 | EXPORT_SYMBOL(vfs_rmdir); |
| 2910 | EXPORT_SYMBOL(vfs_symlink); |
| 2911 | EXPORT_SYMBOL(vfs_unlink); |
| 2912 | EXPORT_SYMBOL(dentry_unhash); |
| 2913 | EXPORT_SYMBOL(generic_readlink); |