blob: 6ad9a21f245982ce8cf6102ffdf084eb1302dae6 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/open.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/string.h>
8#include <linux/mm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/file.h>
Al Viro9f3acc32008-04-24 07:44:08 -040010#include <linux/fdtable.h>
Robert Love0eeca282005-07-12 17:06:03 -040011#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/tty.h>
14#include <linux/namei.h>
15#include <linux/backing-dev.h>
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080016#include <linux/capability.h>
Andrew G. Morgan086f7312008-07-04 09:59:58 -070017#include <linux/securebits.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/security.h>
19#include <linux/mount.h>
Ulrich Drepper5590ff02006-01-18 17:43:53 -080020#include <linux/fcntl.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <asm/uaccess.h>
23#include <linux/fs.h>
Yoav Zachef3daed2005-06-23 00:09:58 -070024#include <linux/personality.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/pagemap.h>
26#include <linux/syscalls.h>
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070027#include <linux/rcupdate.h>
Amy Griffis73241cc2005-11-03 16:00:25 +000028#include <linux/audit.h>
Amit Arora97ac7352007-07-17 21:42:44 -040029#include <linux/falloc.h>
Al Viro5ad4e532009-03-29 19:50:06 -040030#include <linux/fs_struct.h>
Al Virob65a9cf2009-12-16 06:27:40 -050031#include <linux/ima.h>
Eric Paris2dfc1ca2009-12-17 20:30:52 -050032#include <linux/dnotify.h>
Al Viro3f6d0782013-02-24 13:49:08 -050033#include <linux/compat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Eric Parise81e3f42009-12-04 15:47:36 -050035#include "internal.h"
36
NeilBrown4a301312006-01-08 01:02:39 -080037int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
38 struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -070039{
Amerigo Wang939a9422009-08-20 19:29:03 -070040 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 struct iattr newattrs;
42
43 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
44 if (length < 0)
45 return -EINVAL;
46
47 newattrs.ia_size = length;
NeilBrown4a301312006-01-08 01:02:39 -080048 newattrs.ia_valid = ATTR_SIZE | time_attrs;
Miklos Szeredicc4e69d2005-11-07 00:59:49 -080049 if (filp) {
50 newattrs.ia_file = filp;
51 newattrs.ia_valid |= ATTR_FILE;
52 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Jan Kara45f147a2015-05-21 16:05:55 +020054 /* Remove suid, sgid, and file capabilities on truncate too */
55 ret = dentry_needs_remove_privs(dentry);
56 if (ret < 0)
57 return ret;
Amerigo Wang939a9422009-08-20 19:29:03 -070058 if (ret)
59 newattrs.ia_valid |= ret | ATTR_FORCE;
Linus Torvalds7b82dc02007-05-08 20:10:00 -070060
Al Viro59551022016-01-22 15:40:57 -050061 inode_lock(dentry->d_inode);
J. Bruce Fields27ac0ff2011-09-20 17:19:26 -040062 /* Note any delegations or leases have already been broken: */
63 ret = notify_change(dentry, &newattrs, NULL);
Al Viro59551022016-01-22 15:40:57 -050064 inode_unlock(dentry->d_inode);
Amerigo Wang939a9422009-08-20 19:29:03 -070065 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066}
67
Al Viro7df818b2016-03-25 14:24:09 -040068long vfs_truncate(const struct path *path, loff_t length)
Linus Torvalds1da177e2005-04-16 15:20:36 -070069{
Al Viro2d8f3032008-07-22 09:59:21 -040070 struct inode *inode;
Miklos Szeredi4d0c5ba2016-09-16 12:44:21 +020071 struct dentry *upperdentry;
David Howellsa02de962012-12-20 21:52:36 +000072 long error;
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
David Howellsa02de962012-12-20 21:52:36 +000074 inode = path->dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
76 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 if (S_ISDIR(inode->i_mode))
David Howellsa02de962012-12-20 21:52:36 +000078 return -EISDIR;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 if (!S_ISREG(inode->i_mode))
David Howellsa02de962012-12-20 21:52:36 +000080 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
David Howellsa02de962012-12-20 21:52:36 +000082 error = mnt_want_write(path->mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 if (error)
David Howellsa02de962012-12-20 21:52:36 +000084 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Al Viro256984a2008-07-22 08:09:30 -040086 error = inode_permission(inode, MAY_WRITE);
Dave Hansen9ac9b842008-02-15 14:37:52 -080087 if (error)
88 goto mnt_drop_write_and_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089
90 error = -EPERM;
Miklos Szeredic82e42d2008-06-24 16:50:12 +020091 if (IS_APPEND(inode))
Dave Hansen9ac9b842008-02-15 14:37:52 -080092 goto mnt_drop_write_and_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Miklos Szeredi4d0c5ba2016-09-16 12:44:21 +020094 /*
95 * If this is an overlayfs then do as if opening the file so we get
96 * write access on the upper inode, not on the overlay inode. For
97 * non-overlay filesystems d_real() is an identity function.
98 */
99 upperdentry = d_real(path->dentry, NULL, O_WRONLY);
100 error = PTR_ERR(upperdentry);
101 if (IS_ERR(upperdentry))
102 goto mnt_drop_write_and_out;
103
104 error = get_write_access(upperdentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 if (error)
Dave Hansen9ac9b842008-02-15 14:37:52 -0800106 goto mnt_drop_write_and_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107
david m. richter97003822007-07-31 00:39:12 -0700108 /*
109 * Make sure that there are no leases. get_write_access() protects
110 * against the truncate racing with a lease-granting setlease().
111 */
Al Viro8737c932009-12-24 06:47:55 -0500112 error = break_lease(inode, O_WRONLY);
david m. richter97003822007-07-31 00:39:12 -0700113 if (error)
114 goto put_write_and_out;
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 error = locks_verify_truncate(inode, NULL, length);
Kentaro Takedabe6d3e52008-12-17 13:24:15 +0900117 if (!error)
David Howellsa02de962012-12-20 21:52:36 +0000118 error = security_path_truncate(path);
Christoph Hellwig907f4552010-03-03 09:05:06 -0500119 if (!error)
David Howellsa02de962012-12-20 21:52:36 +0000120 error = do_truncate(path->dentry, length, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
david m. richter97003822007-07-31 00:39:12 -0700122put_write_and_out:
Miklos Szeredi4d0c5ba2016-09-16 12:44:21 +0200123 put_write_access(upperdentry->d_inode);
Dave Hansen9ac9b842008-02-15 14:37:52 -0800124mnt_drop_write_and_out:
David Howellsa02de962012-12-20 21:52:36 +0000125 mnt_drop_write(path->mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126out:
127 return error;
128}
David Howellsa02de962012-12-20 21:52:36 +0000129EXPORT_SYMBOL_GPL(vfs_truncate);
130
131static long do_sys_truncate(const char __user *pathname, loff_t length)
132{
Jeff Layton48f75302012-12-11 12:10:11 -0500133 unsigned int lookup_flags = LOOKUP_FOLLOW;
David Howellsa02de962012-12-20 21:52:36 +0000134 struct path path;
135 int error;
136
137 if (length < 0) /* sorry, but loff_t says... */
138 return -EINVAL;
139
Jeff Layton48f75302012-12-11 12:10:11 -0500140retry:
141 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
David Howellsa02de962012-12-20 21:52:36 +0000142 if (!error) {
143 error = vfs_truncate(&path, length);
144 path_put(&path);
145 }
Jeff Layton48f75302012-12-11 12:10:11 -0500146 if (retry_estale(error, lookup_flags)) {
147 lookup_flags |= LOOKUP_REVAL;
148 goto retry;
149 }
David Howellsa02de962012-12-20 21:52:36 +0000150 return error;
151}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
Heiko Carstens4fd8da82009-09-23 17:49:55 +0200153SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154{
Heiko Carstens4fd8da82009-09-23 17:49:55 +0200155 return do_sys_truncate(path, length);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156}
157
Al Viro3f6d0782013-02-24 13:49:08 -0500158#ifdef CONFIG_COMPAT
159COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
160{
161 return do_sys_truncate(path, length);
162}
163#endif
164
Matt Mackallb01ec0e2006-01-08 01:05:20 -0800165static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166{
Al Virobf2965d2012-08-26 20:13:36 -0400167 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 struct dentry *dentry;
Al Viro2903ff02012-08-28 12:52:22 -0400169 struct fd f;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 int error;
171
172 error = -EINVAL;
173 if (length < 0)
174 goto out;
175 error = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -0400176 f = fdget(fd);
177 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 goto out;
179
180 /* explicitly opened as large or we are on 64-bit box */
Al Viro2903ff02012-08-28 12:52:22 -0400181 if (f.file->f_flags & O_LARGEFILE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 small = 0;
183
Al Viro2903ff02012-08-28 12:52:22 -0400184 dentry = f.file->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 inode = dentry->d_inode;
186 error = -EINVAL;
Al Viro2903ff02012-08-28 12:52:22 -0400187 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 goto out_putf;
189
190 error = -EINVAL;
191 /* Cannot ftruncate over 2^31 bytes without large file support */
192 if (small && length > MAX_NON_LFS)
193 goto out_putf;
194
195 error = -EPERM;
196 if (IS_APPEND(inode))
197 goto out_putf;
198
Jan Kara14da9202012-06-12 16:20:37 +0200199 sb_start_write(inode->i_sb);
Al Viro2903ff02012-08-28 12:52:22 -0400200 error = locks_verify_truncate(inode, f.file, length);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 if (!error)
Al Viro2903ff02012-08-28 12:52:22 -0400202 error = security_path_truncate(&f.file->f_path);
Kentaro Takedabe6d3e52008-12-17 13:24:15 +0900203 if (!error)
Al Viro2903ff02012-08-28 12:52:22 -0400204 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
Jan Kara14da9202012-06-12 16:20:37 +0200205 sb_end_write(inode->i_sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206out_putf:
Al Viro2903ff02012-08-28 12:52:22 -0400207 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208out:
209 return error;
210}
211
Heiko Carstensbdc480e2009-01-14 14:14:12 +0100212SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
Al Viro2cf09662013-01-21 15:25:54 -0500214 return do_sys_ftruncate(fd, length, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215}
216
Al Viro3f6d0782013-02-24 13:49:08 -0500217#ifdef CONFIG_COMPAT
218COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
219{
220 return do_sys_ftruncate(fd, length, 1);
221}
222#endif
223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224/* LFS versions of truncate are only needed on 32 bit machines */
225#if BITS_PER_LONG == 32
Al Viro4a0fd5b2013-01-21 15:16:58 -0500226SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227{
228 return do_sys_truncate(path, length);
229}
230
Al Viro4a0fd5b2013-01-21 15:16:58 -0500231SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232{
Al Viro2cf09662013-01-21 15:25:54 -0500233 return do_sys_ftruncate(fd, length, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100235#endif /* BITS_PER_LONG == 32 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400237
Anna Schumaker72c72bd2014-11-07 14:44:25 -0500238int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
Amit Arora97ac7352007-07-17 21:42:44 -0400239{
Al Viro496ad9a2013-01-23 17:07:38 -0500240 struct inode *inode = file_inode(file);
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400241 long ret;
Amit Arora97ac7352007-07-17 21:42:44 -0400242
243 if (offset < 0 || len <= 0)
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400244 return -EINVAL;
Amit Arora97ac7352007-07-17 21:42:44 -0400245
246 /* Return error if mode is not supported */
Namjae Jeondd46c782015-03-25 15:07:05 +1100247 if (mode & ~FALLOC_FL_SUPPORTED_MASK)
Lukas Czerner409332b2014-03-13 19:07:42 +1100248 return -EOPNOTSUPP;
249
250 /* Punch hole and zero range are mutually exclusive */
251 if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
252 (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
Josef Bacik79124f182010-11-17 20:46:15 -0500253 return -EOPNOTSUPP;
254
255 /* Punch hole must have keep size set */
256 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
257 !(mode & FALLOC_FL_KEEP_SIZE))
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400258 return -EOPNOTSUPP;
Amit Arora97ac7352007-07-17 21:42:44 -0400259
Namjae Jeon00f5e612014-02-24 10:58:15 +1100260 /* Collapse range should only be used exclusively. */
261 if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
262 (mode & ~FALLOC_FL_COLLAPSE_RANGE))
263 return -EINVAL;
264
Namjae Jeondd46c782015-03-25 15:07:05 +1100265 /* Insert range should only be used exclusively. */
266 if ((mode & FALLOC_FL_INSERT_RANGE) &&
267 (mode & ~FALLOC_FL_INSERT_RANGE))
268 return -EINVAL;
269
Darrick J. Wong71be6b42016-10-03 09:11:14 -0700270 /* Unshare range should only be used with allocate mode. */
271 if ((mode & FALLOC_FL_UNSHARE_RANGE) &&
272 (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE)))
273 return -EINVAL;
274
Amit Arora97ac7352007-07-17 21:42:44 -0400275 if (!(file->f_mode & FMODE_WRITE))
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400276 return -EBADF;
Marco Stornelli1ca551c2011-03-05 11:10:19 +0100277
Namjae Jeon00f5e612014-02-24 10:58:15 +1100278 /*
Lukas Czerner8fc61d92014-04-12 09:51:34 -0400279 * We can only allow pure fallocate on append only files
Namjae Jeon00f5e612014-02-24 10:58:15 +1100280 */
Lukas Czerner8fc61d92014-04-12 09:51:34 -0400281 if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
Marco Stornelli1ca551c2011-03-05 11:10:19 +0100282 return -EPERM;
283
284 if (IS_IMMUTABLE(inode))
285 return -EPERM;
286
Amit Arora97ac7352007-07-17 21:42:44 -0400287 /*
Eric Biggers6d2b6172014-06-24 23:45:08 -0500288 * We cannot allow any fallocate operation on an active swapfile
Lukas Czerner0790b312014-04-12 10:05:37 -0400289 */
290 if (IS_SWAPFILE(inode))
Eric Biggers6d2b6172014-06-24 23:45:08 -0500291 return -ETXTBSY;
Lukas Czerner0790b312014-04-12 10:05:37 -0400292
293 /*
Amit Arora97ac7352007-07-17 21:42:44 -0400294 * Revalidate the write permissions, in case security policy has
295 * changed since the files were opened.
296 */
297 ret = security_file_permission(file, MAY_WRITE);
298 if (ret)
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400299 return ret;
Amit Arora97ac7352007-07-17 21:42:44 -0400300
Amit Arora97ac7352007-07-17 21:42:44 -0400301 if (S_ISFIFO(inode->i_mode))
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400302 return -ESPIPE;
Amit Arora97ac7352007-07-17 21:42:44 -0400303
Amit Arora97ac7352007-07-17 21:42:44 -0400304 /*
305 * Let individual file system decide if it supports preallocation
306 * for directories or not.
307 */
Darrick J. Wong25f4c412016-10-11 13:51:11 -0700308 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode) &&
309 !S_ISBLK(inode->i_mode))
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400310 return -ENODEV;
Amit Arora97ac7352007-07-17 21:42:44 -0400311
Amit Arora97ac7352007-07-17 21:42:44 -0400312 /* Check for wrap through zero too */
313 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400314 return -EFBIG;
Amit Arora97ac7352007-07-17 21:42:44 -0400315
Christoph Hellwig2fe17c12011-01-14 13:07:43 +0100316 if (!file->f_op->fallocate)
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400317 return -EOPNOTSUPP;
Amit Arora97ac7352007-07-17 21:42:44 -0400318
Jan Kara14da9202012-06-12 16:20:37 +0200319 sb_start_write(inode->i_sb);
320 ret = file->f_op->fallocate(file, mode, offset, len);
Heinrich Schuchardt820c12d2014-12-12 16:58:34 -0800321
322 /*
323 * Create inotify and fanotify events.
324 *
325 * To keep the logic simple always create events if fallocate succeeds.
326 * This implies that events are even created if the file size remains
327 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
328 */
329 if (ret == 0)
330 fsnotify_modify(file);
331
Jan Kara14da9202012-06-12 16:20:37 +0200332 sb_end_write(inode->i_sb);
333 return ret;
Amit Arora97ac7352007-07-17 21:42:44 -0400334}
Anna Schumaker72c72bd2014-11-07 14:44:25 -0500335EXPORT_SYMBOL_GPL(vfs_fallocate);
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400336
Al Viro4a0fd5b2013-01-21 15:16:58 -0500337SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400338{
Al Viro2903ff02012-08-28 12:52:22 -0400339 struct fd f = fdget(fd);
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400340 int error = -EBADF;
341
Al Viro2903ff02012-08-28 12:52:22 -0400342 if (f.file) {
Anna Schumaker72c72bd2014-11-07 14:44:25 -0500343 error = vfs_fallocate(f.file, mode, offset, len);
Al Viro2903ff02012-08-28 12:52:22 -0400344 fdput(f);
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400345 }
Ankit Jain3e63cbb2009-06-19 14:28:07 -0400346 return error;
347}
348
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349/*
350 * access() needs to use the real uid/gid, not the effective uid/gid.
351 * We do this by temporarily clearing all FS-related capabilities and
352 * switching the fsuid/fsgid around to the real ones.
353 */
Heiko Carstens6559eed82009-01-14 14:14:32 +0100354SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355{
David Howellsd84f4f92008-11-14 10:39:23 +1100356 const struct cred *old_cred;
357 struct cred *override_cred;
Al Viro2d8f3032008-07-22 09:59:21 -0400358 struct path path;
Al Viro256984a2008-07-22 08:09:30 -0400359 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 int res;
Jeff Layton87fa5592012-12-11 12:10:11 -0500361 unsigned int lookup_flags = LOOKUP_FOLLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
363 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
364 return -EINVAL;
365
David Howellsd84f4f92008-11-14 10:39:23 +1100366 override_cred = prepare_creds();
367 if (!override_cred)
368 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369
David Howellsd84f4f92008-11-14 10:39:23 +1100370 override_cred->fsuid = override_cred->uid;
371 override_cred->fsgid = override_cred->gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372
Andrew G. Morgan086f7312008-07-04 09:59:58 -0700373 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
David Howells1cdcbec2008-11-14 10:39:14 +1100374 /* Clear the capabilities if we switch to a non-root user */
Eric W. Biederman18815a12012-02-07 16:45:47 -0800375 kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
376 if (!uid_eq(override_cred->uid, root_uid))
David Howellsd84f4f92008-11-14 10:39:23 +1100377 cap_clear(override_cred->cap_effective);
Andrew G. Morgan086f7312008-07-04 09:59:58 -0700378 else
David Howellsd84f4f92008-11-14 10:39:23 +1100379 override_cred->cap_effective =
380 override_cred->cap_permitted;
Andrew G. Morgan086f7312008-07-04 09:59:58 -0700381 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382
David Howellsd84f4f92008-11-14 10:39:23 +1100383 old_cred = override_creds(override_cred);
Jeff Layton87fa5592012-12-11 12:10:11 -0500384retry:
385 res = user_path_at(dfd, filename, lookup_flags, &path);
Dave Hansen6902d922006-09-30 23:29:01 -0700386 if (res)
387 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388
David Howells63afdfc2015-05-06 15:59:00 +0100389 inode = d_backing_inode(path.dentry);
Al Viro256984a2008-07-22 08:09:30 -0400390
391 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
Al Viro30524472008-07-22 00:02:33 -0400392 /*
393 * MAY_EXEC on regular files is denied if the fs is mounted
394 * with the "noexec" flag.
395 */
396 res = -EACCES;
Eric W. Biederman90f85722015-06-29 14:42:03 -0500397 if (path_noexec(&path))
Al Viro30524472008-07-22 00:02:33 -0400398 goto out_path_release;
399 }
400
Al Viro256984a2008-07-22 08:09:30 -0400401 res = inode_permission(inode, mode | MAY_ACCESS);
Dave Hansen6902d922006-09-30 23:29:01 -0700402 /* SuS v2 requires we report a read only fs too */
Al Viro256984a2008-07-22 08:09:30 -0400403 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
Dave Hansen6902d922006-09-30 23:29:01 -0700404 goto out_path_release;
Dave Hansen2f676cb2008-02-15 14:37:55 -0800405 /*
406 * This is a rare case where using __mnt_is_readonly()
407 * is OK without a mnt_want/drop_write() pair. Since
408 * no actual write to the fs is performed here, we do
409 * not need to telegraph to that to anyone.
410 *
411 * By doing this, we accept that this access is
412 * inherently racy and know that the fs may change
413 * state before we even see this result.
414 */
Al Viro2d8f3032008-07-22 09:59:21 -0400415 if (__mnt_is_readonly(path.mnt))
Dave Hansen6902d922006-09-30 23:29:01 -0700416 res = -EROFS;
417
418out_path_release:
Al Viro2d8f3032008-07-22 09:59:21 -0400419 path_put(&path);
Jeff Layton87fa5592012-12-11 12:10:11 -0500420 if (retry_estale(res, lookup_flags)) {
421 lookup_flags |= LOOKUP_REVAL;
422 goto retry;
423 }
Dave Hansen6902d922006-09-30 23:29:01 -0700424out:
David Howellsd84f4f92008-11-14 10:39:23 +1100425 revert_creds(old_cred);
426 put_cred(override_cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 return res;
428}
429
Heiko Carstensca013e92009-01-14 14:14:19 +0100430SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800431{
432 return sys_faccessat(AT_FDCWD, filename, mode);
433}
434
Heiko Carstens3cdad422009-01-14 14:14:22 +0100435SYSCALL_DEFINE1(chdir, const char __user *, filename)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436{
Al Viro2d8f3032008-07-22 09:59:21 -0400437 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 int error;
Jeff Layton0291c0a2012-12-11 12:10:12 -0500439 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
440retry:
441 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 if (error)
443 goto out;
444
Eric Paris9cfcac82010-07-23 11:43:51 -0400445 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 if (error)
447 goto dput_and_out;
448
Al Viro2d8f3032008-07-22 09:59:21 -0400449 set_fs_pwd(current->fs, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450
451dput_and_out:
Al Viro2d8f3032008-07-22 09:59:21 -0400452 path_put(&path);
Jeff Layton0291c0a2012-12-11 12:10:12 -0500453 if (retry_estale(error, lookup_flags)) {
454 lookup_flags |= LOOKUP_REVAL;
455 goto retry;
456 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457out:
458 return error;
459}
460
Heiko Carstens3cdad422009-01-14 14:14:22 +0100461SYSCALL_DEFINE1(fchdir, unsigned int, fd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462{
Al Viro2903ff02012-08-28 12:52:22 -0400463 struct fd f = fdget_raw(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 struct inode *inode;
Al Viro2903ff02012-08-28 12:52:22 -0400465 int error = -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466
467 error = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -0400468 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 goto out;
470
Al Viro496ad9a2013-01-23 17:07:38 -0500471 inode = file_inode(f.file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472
473 error = -ENOTDIR;
474 if (!S_ISDIR(inode->i_mode))
475 goto out_putf;
476
Eric Paris9cfcac82010-07-23 11:43:51 -0400477 error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 if (!error)
Al Viro2903ff02012-08-28 12:52:22 -0400479 set_fs_pwd(current->fs, &f.file->f_path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480out_putf:
Al Viro2903ff02012-08-28 12:52:22 -0400481 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482out:
483 return error;
484}
485
Heiko Carstens3480b252009-01-14 14:14:16 +0100486SYSCALL_DEFINE1(chroot, const char __user *, filename)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487{
Al Viro2d8f3032008-07-22 09:59:21 -0400488 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 int error;
Jeff Layton27712612012-12-20 17:08:32 -0500490 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
491retry:
492 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 if (error)
494 goto out;
495
Eric Paris9cfcac82010-07-23 11:43:51 -0400496 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 if (error)
498 goto dput_and_out;
499
500 error = -EPERM;
Eric W. Biedermanc7b96ac2013-03-20 12:49:49 -0700501 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 goto dput_and_out;
Tetsuo Handa8b8efb42009-10-04 21:49:48 +0900503 error = security_path_chroot(&path);
504 if (error)
505 goto dput_and_out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506
Al Viro2d8f3032008-07-22 09:59:21 -0400507 set_fs_root(current->fs, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 error = 0;
509dput_and_out:
Al Viro2d8f3032008-07-22 09:59:21 -0400510 path_put(&path);
Jeff Layton27712612012-12-20 17:08:32 -0500511 if (retry_estale(error, lookup_flags)) {
512 lookup_flags |= LOOKUP_REVAL;
513 goto retry;
514 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515out:
516 return error;
517}
518
Al Virobe01f9f2016-03-25 14:56:23 -0400519static int chmod_common(const struct path *path, umode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520{
Al Viroe57712e2011-07-26 04:15:54 -0400521 struct inode *inode = path->dentry->d_inode;
J. Bruce Fields27ac0ff2011-09-20 17:19:26 -0400522 struct inode *delegated_inode = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 struct iattr newattrs;
Al Viroe57712e2011-07-26 04:15:54 -0400524 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525
Al Viroe57712e2011-07-26 04:15:54 -0400526 error = mnt_want_write(path->mnt);
527 if (error)
528 return error;
J. Bruce Fields27ac0ff2011-09-20 17:19:26 -0400529retry_deleg:
Al Viro59551022016-01-22 15:40:57 -0500530 inode_lock(inode);
Al Virocdcf1162011-12-08 10:51:53 -0500531 error = security_path_chmod(path, mode);
Al Viroe57712e2011-07-26 04:15:54 -0400532 if (error)
Tetsuo Handafe542cf2009-11-22 11:49:55 +0900533 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
535 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
J. Bruce Fields27ac0ff2011-09-20 17:19:26 -0400536 error = notify_change(path->dentry, &newattrs, &delegated_inode);
Tetsuo Handafe542cf2009-11-22 11:49:55 +0900537out_unlock:
Al Viro59551022016-01-22 15:40:57 -0500538 inode_unlock(inode);
J. Bruce Fields27ac0ff2011-09-20 17:19:26 -0400539 if (delegated_inode) {
540 error = break_deleg_wait(&delegated_inode);
541 if (!error)
542 goto retry_deleg;
543 }
Al Viroe57712e2011-07-26 04:15:54 -0400544 mnt_drop_write(path->mnt);
545 return error;
546}
547
Al Viro49f0a072011-07-26 04:22:01 -0400548SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
Al Viroe57712e2011-07-26 04:15:54 -0400549{
Al Viro173c8402013-08-30 12:48:53 -0400550 struct fd f = fdget(fd);
Al Viroe57712e2011-07-26 04:15:54 -0400551 int err = -EBADF;
552
Al Viro173c8402013-08-30 12:48:53 -0400553 if (f.file) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400554 audit_file(f.file);
Al Viro173c8402013-08-30 12:48:53 -0400555 err = chmod_common(&f.file->f_path, mode);
556 fdput(f);
Al Viroe57712e2011-07-26 04:15:54 -0400557 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 return err;
559}
560
Al Viro49f0a072011-07-26 04:22:01 -0400561SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562{
Al Viro2d8f3032008-07-22 09:59:21 -0400563 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 int error;
Jeff Layton14ff6902012-12-11 12:10:13 -0500565 unsigned int lookup_flags = LOOKUP_FOLLOW;
566retry:
567 error = user_path_at(dfd, filename, lookup_flags, &path);
Al Viroe57712e2011-07-26 04:15:54 -0400568 if (!error) {
569 error = chmod_common(&path, mode);
570 path_put(&path);
Jeff Layton14ff6902012-12-11 12:10:13 -0500571 if (retry_estale(error, lookup_flags)) {
572 lookup_flags |= LOOKUP_REVAL;
573 goto retry;
574 }
Al Viroe57712e2011-07-26 04:15:54 -0400575 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 return error;
577}
578
Al Viro49f0a072011-07-26 04:22:01 -0400579SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800580{
581 return sys_fchmodat(AT_FDCWD, filename, mode);
582}
583
Al Viro7fd25da2016-03-25 14:44:41 -0400584static int chown_common(const struct path *path, uid_t user, gid_t group)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585{
Tetsuo Handafe542cf2009-11-22 11:49:55 +0900586 struct inode *inode = path->dentry->d_inode;
J. Bruce Fields27ac0ff2011-09-20 17:19:26 -0400587 struct inode *delegated_inode = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 int error;
589 struct iattr newattrs;
Eric W. Biederman52137ab2012-03-03 19:52:01 -0800590 kuid_t uid;
591 kgid_t gid;
592
593 uid = make_kuid(current_user_ns(), user);
594 gid = make_kgid(current_user_ns(), group);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595
Andrew Elblec1b89402015-02-23 08:51:24 -0500596retry_deleg:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 newattrs.ia_valid = ATTR_CTIME;
598 if (user != (uid_t) -1) {
Eric W. Biederman52137ab2012-03-03 19:52:01 -0800599 if (!uid_valid(uid))
600 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 newattrs.ia_valid |= ATTR_UID;
Eric W. Biederman52137ab2012-03-03 19:52:01 -0800602 newattrs.ia_uid = uid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 }
604 if (group != (gid_t) -1) {
Eric W. Biederman52137ab2012-03-03 19:52:01 -0800605 if (!gid_valid(gid))
606 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 newattrs.ia_valid |= ATTR_GID;
Eric W. Biederman52137ab2012-03-03 19:52:01 -0800608 newattrs.ia_gid = gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 }
610 if (!S_ISDIR(inode->i_mode))
Serge E. Hallynb5376772007-10-16 23:31:36 -0700611 newattrs.ia_valid |=
612 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
Al Viro59551022016-01-22 15:40:57 -0500613 inode_lock(inode);
Eric W. Biedermand2b31ca2012-06-01 16:14:19 -0600614 error = security_path_chown(path, uid, gid);
Tetsuo Handafe542cf2009-11-22 11:49:55 +0900615 if (!error)
J. Bruce Fields27ac0ff2011-09-20 17:19:26 -0400616 error = notify_change(path->dentry, &newattrs, &delegated_inode);
Al Viro59551022016-01-22 15:40:57 -0500617 inode_unlock(inode);
J. Bruce Fields27ac0ff2011-09-20 17:19:26 -0400618 if (delegated_inode) {
619 error = break_deleg_wait(&delegated_inode);
620 if (!error)
621 goto retry_deleg;
622 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 return error;
624}
625
Heiko Carstens6559eed82009-01-14 14:14:32 +0100626SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
627 gid_t, group, int, flag)
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800628{
Al Viro2d8f3032008-07-22 09:59:21 -0400629 struct path path;
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800630 int error = -EINVAL;
Al Viro65cfc672011-03-13 15:56:26 -0400631 int lookup_flags;
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800632
Al Viro65cfc672011-03-13 15:56:26 -0400633 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800634 goto out;
635
Al Viro65cfc672011-03-13 15:56:26 -0400636 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
637 if (flag & AT_EMPTY_PATH)
638 lookup_flags |= LOOKUP_EMPTY;
Jeff Layton99a5df32012-12-11 12:10:13 -0500639retry:
Al Viro65cfc672011-03-13 15:56:26 -0400640 error = user_path_at(dfd, filename, lookup_flags, &path);
Dave Hansen6902d922006-09-30 23:29:01 -0700641 if (error)
642 goto out;
Al Viro2d8f3032008-07-22 09:59:21 -0400643 error = mnt_want_write(path.mnt);
Dave Hansen2af482a2008-02-15 14:37:50 -0800644 if (error)
645 goto out_release;
Tetsuo Handafe542cf2009-11-22 11:49:55 +0900646 error = chown_common(&path, user, group);
Al Viro2d8f3032008-07-22 09:59:21 -0400647 mnt_drop_write(path.mnt);
Dave Hansen2af482a2008-02-15 14:37:50 -0800648out_release:
Al Viro2d8f3032008-07-22 09:59:21 -0400649 path_put(&path);
Jeff Layton99a5df32012-12-11 12:10:13 -0500650 if (retry_estale(error, lookup_flags)) {
651 lookup_flags |= LOOKUP_REVAL;
652 goto retry;
653 }
Ulrich Drepper5590ff02006-01-18 17:43:53 -0800654out:
655 return error;
656}
657
David Howells55e4def2012-06-25 12:55:09 +0100658SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
659{
660 return sys_fchownat(AT_FDCWD, filename, user, group, 0);
661}
662
Heiko Carstensca013e92009-01-14 14:14:19 +0100663SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664{
David Howells55e4def2012-06-25 12:55:09 +0100665 return sys_fchownat(AT_FDCWD, filename, user, group,
666 AT_SYMLINK_NOFOLLOW);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667}
668
Heiko Carstensca013e92009-01-14 14:14:19 +0100669SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670{
Al Viro2903ff02012-08-28 12:52:22 -0400671 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 int error = -EBADF;
673
Al Viro2903ff02012-08-28 12:52:22 -0400674 if (!f.file)
Dave Hansen6902d922006-09-30 23:29:01 -0700675 goto out;
676
Al Viro2903ff02012-08-28 12:52:22 -0400677 error = mnt_want_write_file(f.file);
Dave Hansen2af482a2008-02-15 14:37:50 -0800678 if (error)
679 goto out_fput;
Al Viro9f45f5b2014-10-31 17:44:57 -0400680 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400681 error = chown_common(&f.file->f_path, user, group);
682 mnt_drop_write_file(f.file);
Dave Hansen2af482a2008-02-15 14:37:50 -0800683out_fput:
Al Viro2903ff02012-08-28 12:52:22 -0400684 fdput(f);
Dave Hansen6902d922006-09-30 23:29:01 -0700685out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 return error;
687}
688
Miklos Szeredi90ad1a82012-05-21 17:30:15 +0200689int open_check_o_direct(struct file *f)
690{
691 /* NB: we're sure to have correct a_ops only after f_op->open */
692 if (f->f_flags & O_DIRECT) {
Matthew Wilcoxe748dcd2015-02-16 15:59:12 -0800693 if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
Miklos Szeredi90ad1a82012-05-21 17:30:15 +0200694 return -EINVAL;
Miklos Szeredi90ad1a82012-05-21 17:30:15 +0200695 }
696 return 0;
697}
698
Al Viro02e51802012-06-10 14:32:45 -0400699static int do_dentry_open(struct file *f,
David Howells4bacc9c2015-06-18 14:32:31 +0100700 struct inode *inode,
Al Viro96b7e572012-06-10 14:22:04 -0400701 int (*open)(struct inode *, struct file *),
702 const struct cred *cred)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703{
Al Viro1abf0c72011-03-13 03:51:11 -0400704 static const struct file_operations empty_fops = {};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 int error;
706
Al Viro53009902009-12-19 10:15:07 -0500707 f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700708 FMODE_PREAD | FMODE_PWRITE;
Al Viro1abf0c72011-03-13 03:51:11 -0400709
Al Virob5bcdda2012-07-20 23:28:46 +0400710 path_get(&f->f_path);
David Howells4bacc9c2015-06-18 14:32:31 +0100711 f->f_inode = inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 f->f_mapping = inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713
Al Viro3f4d5a02014-03-14 09:43:29 -0400714 if (unlikely(f->f_flags & O_PATH)) {
715 f->f_mode = FMODE_PATH;
Al Viro1abf0c72011-03-13 03:51:11 -0400716 f->f_op = &empty_fops;
Al Viro96b7e572012-06-10 14:22:04 -0400717 return 0;
Al Viro1abf0c72011-03-13 03:51:11 -0400718 }
719
Tetsuo Handa7d7637d2019-03-28 20:43:30 -0700720 /* Any file opened for execve()/uselib() has to be a regular file. */
721 if (unlikely(f->f_flags & FMODE_EXEC && !S_ISREG(inode->i_mode))) {
722 error = -EACCES;
723 goto cleanup_file;
724 }
725
Al Virodd209082014-03-14 10:56:20 -0400726 if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
Al Viro0ccb2862014-03-14 10:40:46 -0400727 error = get_write_access(inode);
Al Viro3f4d5a02014-03-14 09:43:29 -0400728 if (unlikely(error))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 goto cleanup_file;
Al Viro0ccb2862014-03-14 10:40:46 -0400730 error = __mnt_want_write(f->f_path.mnt);
Al Viro3f4d5a02014-03-14 09:43:29 -0400731 if (unlikely(error)) {
Al Viro0ccb2862014-03-14 10:40:46 -0400732 put_write_access(inode);
733 goto cleanup_file;
734 }
Al Viro83f936c2014-03-14 12:02:47 -0400735 f->f_mode |= FMODE_WRITER;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 }
737
Linus Torvalds9c225f22014-03-03 09:36:58 -0800738 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
Al Viro63b6df12016-04-20 17:08:21 -0400739 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
Linus Torvalds9c225f22014-03-03 09:36:58 -0800740 f->f_mode |= FMODE_ATOMIC_POS;
741
Al Viro1abf0c72011-03-13 03:51:11 -0400742 f->f_op = fops_get(inode->i_fop);
Al Viro72c2d532013-09-22 16:27:52 -0400743 if (unlikely(WARN_ON(!f->f_op))) {
744 error = -ENODEV;
745 goto cleanup_all;
746 }
Al Viro1abf0c72011-03-13 03:51:11 -0400747
Eric Paris83d49852012-04-04 13:45:40 -0400748 error = security_file_open(f, cred);
Yuichi Nakamura788e7dd2007-09-14 09:27:07 +0900749 if (error)
750 goto cleanup_all;
751
Miklos Szeredic568d682016-09-16 12:44:20 +0200752 error = break_lease(locks_inode(f), f->f_flags);
J. Bruce Fieldsf3c7691e2011-09-21 10:58:13 -0400753 if (error)
754 goto cleanup_all;
755
Al Viro72c2d532013-09-22 16:27:52 -0400756 if (!open)
Trond Myklebust834f2a42005-10-18 14:20:16 -0700757 open = f->f_op->open;
758 if (open) {
759 error = open(inode, f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 if (error)
761 goto cleanup_all;
762 }
Mimi Zohar890275b52010-11-02 10:13:07 -0400763 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
764 i_readcount_inc(inode);
Al Viro293bc982014-02-11 18:37:41 -0500765 if ((f->f_mode & FMODE_READ) &&
Al Viro84363182015-04-04 01:14:53 -0400766 likely(f->f_op->read || f->f_op->read_iter))
Al Viro7f7f25e2014-02-11 17:49:24 -0500767 f->f_mode |= FMODE_CAN_READ;
Al Viro293bc982014-02-11 18:37:41 -0500768 if ((f->f_mode & FMODE_WRITE) &&
Al Viro84363182015-04-04 01:14:53 -0400769 likely(f->f_op->write || f->f_op->write_iter))
Al Viro7f7f25e2014-02-11 17:49:24 -0500770 f->f_mode |= FMODE_CAN_WRITE;
Trond Myklebust834f2a42005-10-18 14:20:16 -0700771
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
773
774 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
775
Al Viro96b7e572012-06-10 14:22:04 -0400776 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777
778cleanup_all:
779 fops_put(f->f_op);
Al Viro83f936c2014-03-14 12:02:47 -0400780 if (f->f_mode & FMODE_WRITER) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 put_write_access(inode);
Al Viro83f936c2014-03-14 12:02:47 -0400782 __mnt_drop_write(f->f_path.mnt);
Dave Hansen4a3fd212008-02-15 14:37:48 -0800783 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784cleanup_file:
Al Viro02e51802012-06-10 14:32:45 -0400785 path_put(&f->f_path);
786 f->f_path.mnt = NULL;
787 f->f_path.dentry = NULL;
Al Virodd379782013-03-01 19:48:30 -0500788 f->f_inode = NULL;
Al Viro96b7e572012-06-10 14:22:04 -0400789 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790}
791
Trond Myklebust834f2a42005-10-18 14:20:16 -0700792/**
Miklos Szeredid18e9002012-06-05 15:10:17 +0200793 * finish_open - finish opening a file
Miklos Szeredi0854d452013-09-16 14:51:55 +0200794 * @file: file pointer
Miklos Szeredid18e9002012-06-05 15:10:17 +0200795 * @dentry: pointer to dentry
796 * @open: open callback
Miklos Szeredi0854d452013-09-16 14:51:55 +0200797 * @opened: state of open
Miklos Szeredid18e9002012-06-05 15:10:17 +0200798 *
799 * This can be used to finish opening a file passed to i_op->atomic_open().
800 *
801 * If the open callback is set to NULL, then the standard f_op->open()
802 * filesystem callback is substituted.
Miklos Szeredi0854d452013-09-16 14:51:55 +0200803 *
804 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
805 * the return value of d_splice_alias(), then the caller needs to perform dput()
806 * on it after finish_open().
807 *
808 * On successful return @file is a fully instantiated open file. After this, if
809 * an error occurs in ->atomic_open(), it needs to clean up with fput().
810 *
811 * Returns zero on success or -errno if the open failed.
Miklos Szeredid18e9002012-06-05 15:10:17 +0200812 */
Al Viro30d90492012-06-22 12:40:19 +0400813int finish_open(struct file *file, struct dentry *dentry,
814 int (*open)(struct inode *, struct file *),
815 int *opened)
Miklos Szeredid18e9002012-06-05 15:10:17 +0200816{
Al Viro96b7e572012-06-10 14:22:04 -0400817 int error;
Al Viro3d8a00d2012-06-10 05:04:43 -0400818 BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
Miklos Szeredid18e9002012-06-05 15:10:17 +0200819
Al Virob5bcdda2012-07-20 23:28:46 +0400820 file->f_path.dentry = dentry;
David Howells4bacc9c2015-06-18 14:32:31 +0100821 error = do_dentry_open(file, d_backing_inode(dentry), open,
822 current_cred());
Al Viro96b7e572012-06-10 14:22:04 -0400823 if (!error)
Al Viro47237682012-06-10 05:01:45 -0400824 *opened |= FILE_OPENED;
Miklos Szeredid18e9002012-06-05 15:10:17 +0200825
Al Viro96b7e572012-06-10 14:22:04 -0400826 return error;
Miklos Szeredid18e9002012-06-05 15:10:17 +0200827}
828EXPORT_SYMBOL(finish_open);
829
830/**
831 * finish_no_open - finish ->atomic_open() without opening the file
832 *
Miklos Szeredi0854d452013-09-16 14:51:55 +0200833 * @file: file pointer
Miklos Szeredid18e9002012-06-05 15:10:17 +0200834 * @dentry: dentry or NULL (as returned from ->lookup())
835 *
836 * This can be used to set the result of a successful lookup in ->atomic_open().
Miklos Szeredi0854d452013-09-16 14:51:55 +0200837 *
838 * NB: unlike finish_open() this function does consume the dentry reference and
839 * the caller need not dput() it.
840 *
841 * Returns "1" which must be the return value of ->atomic_open() after having
842 * called this function.
Miklos Szeredid18e9002012-06-05 15:10:17 +0200843 */
Al Viroe45198a2012-06-10 06:48:09 -0400844int finish_no_open(struct file *file, struct dentry *dentry)
Miklos Szeredid18e9002012-06-05 15:10:17 +0200845{
Al Viro30d90492012-06-22 12:40:19 +0400846 file->f_path.dentry = dentry;
Al Viroe45198a2012-06-10 06:48:09 -0400847 return 1;
Miklos Szeredid18e9002012-06-05 15:10:17 +0200848}
849EXPORT_SYMBOL(finish_no_open);
850
Miklos Szeredi9bf39ab2015-06-19 10:29:13 +0200851char *file_path(struct file *filp, char *buf, int buflen)
852{
853 return d_path(&filp->f_path, buf, buflen);
854}
855EXPORT_SYMBOL(file_path);
856
David Howells4bacc9c2015-06-18 14:32:31 +0100857/**
858 * vfs_open - open the file at the given path
859 * @path: path to open
860 * @file: newly allocated file with f_flag initialized
861 * @cred: credentials to use
862 */
863int vfs_open(const struct path *path, struct file *file,
864 const struct cred *cred)
865{
Miklos Szeredi2d902672016-06-30 08:53:27 +0200866 struct dentry *dentry = d_real(path->dentry, NULL, file->f_flags);
Miklos Szeredi54d5ca82016-05-11 01:16:37 +0200867
Miklos Szeredi2d902672016-06-30 08:53:27 +0200868 if (IS_ERR(dentry))
869 return PTR_ERR(dentry);
David Howells4bacc9c2015-06-18 14:32:31 +0100870
871 file->f_path = *path;
Miklos Szeredi2d902672016-06-30 08:53:27 +0200872 return do_dentry_open(file, d_backing_inode(dentry), NULL, cred);
David Howells4bacc9c2015-06-18 14:32:31 +0100873}
874
Al Viro765927b2012-06-26 21:58:53 +0400875struct file *dentry_open(const struct path *path, int flags,
David Howells745ca242008-11-14 10:39:22 +1100876 const struct cred *cred)
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700877{
878 int error;
879 struct file *f;
880
David Howellse0e81732009-09-02 09:13:40 +0100881 validate_creds(cred);
882
Tetsuo Handac212f9a2011-01-19 21:08:41 +0900883 /* We must always pass in a valid mount pointer. */
Al Viro765927b2012-06-26 21:58:53 +0400884 BUG_ON(!path->mnt);
Christoph Hellwig322ee5b2008-02-15 14:37:24 -0800885
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700886 f = get_empty_filp();
Al Viro1afc99b2013-02-14 20:41:04 -0500887 if (!IS_ERR(f)) {
888 f->f_flags = flags;
Miklos Szeredi4aa7c632014-10-24 00:14:35 +0200889 error = vfs_open(path, f, cred);
Al Viro1afc99b2013-02-14 20:41:04 -0500890 if (!error) {
891 /* from now on we need fput() to dispose of f */
892 error = open_check_o_direct(f);
893 if (error) {
894 fput(f);
895 f = ERR_PTR(error);
896 }
897 } else {
898 put_filp(f);
Al Viro2a027e72012-06-10 14:24:38 -0400899 f = ERR_PTR(error);
900 }
Al Viro2a027e72012-06-10 14:24:38 -0400901 }
902 return f;
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700903}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904EXPORT_SYMBOL(dentry_open);
905
Al Viroa218d0f2011-11-21 14:59:34 -0500906static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
Al Viro47c805d2011-02-23 17:44:09 -0500907{
908 int lookup_flags = 0;
Al Viro62fb4a12015-12-26 22:33:24 -0500909 int acc_mode = ACC_MODE(flags);
Al Viro47c805d2011-02-23 17:44:09 -0500910
Christoph Hellwig26ff0652017-04-27 09:42:25 +0200911 /*
912 * Clear out all open flags we don't know about so that we don't report
913 * them in fcntl(F_GETFD) or similar interfaces.
914 */
915 flags &= VALID_OPEN_FLAGS;
916
Andy Lutomirskie305f482013-08-01 21:07:52 -0700917 if (flags & (O_CREAT | __O_TMPFILE))
Miklos Szeredie68726f2012-08-15 13:01:24 +0200918 op->mode = (mode & S_IALLUGO) | S_IFREG;
919 else
920 op->mode = 0;
Al Viro47c805d2011-02-23 17:44:09 -0500921
922 /* Must never be set by userspace */
Al Viroc6f3d812012-08-26 11:01:04 -0400923 flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
Al Viro47c805d2011-02-23 17:44:09 -0500924
925 /*
926 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
927 * check for O_DSYNC if the need any syncing at all we enforce it's
928 * always set instead of having to deal with possibly weird behaviour
929 * for malicious applications setting only __O_SYNC.
930 */
931 if (flags & __O_SYNC)
932 flags |= O_DSYNC;
933
Al Virobb458c62013-07-13 13:26:37 +0400934 if (flags & __O_TMPFILE) {
935 if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
Al Viro60545d02013-06-07 01:20:27 -0400936 return -EINVAL;
Al Viroba57ea62013-07-20 03:11:32 +0400937 if (!(acc_mode & MAY_WRITE))
938 return -EINVAL;
Al Viro60545d02013-06-07 01:20:27 -0400939 } else if (flags & O_PATH) {
940 /*
941 * If we have O_PATH in the open flag. Then we
942 * cannot have anything other than the below set of flags
943 */
Al Viro1abf0c72011-03-13 03:51:11 -0400944 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
945 acc_mode = 0;
Al Viro1abf0c72011-03-13 03:51:11 -0400946 }
Al Viro47c805d2011-02-23 17:44:09 -0500947
Al Viro1abf0c72011-03-13 03:51:11 -0400948 op->open_flag = flags;
Al Viro47c805d2011-02-23 17:44:09 -0500949
950 /* O_TRUNC implies we need access checks for write permissions */
951 if (flags & O_TRUNC)
952 acc_mode |= MAY_WRITE;
953
954 /* Allow the LSM permission hook to distinguish append
955 access from general write access. */
956 if (flags & O_APPEND)
957 acc_mode |= MAY_APPEND;
958
959 op->acc_mode = acc_mode;
960
Al Viro1abf0c72011-03-13 03:51:11 -0400961 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
962
Al Viro47c805d2011-02-23 17:44:09 -0500963 if (flags & O_CREAT) {
964 op->intent |= LOOKUP_CREATE;
965 if (flags & O_EXCL)
966 op->intent |= LOOKUP_EXCL;
967 }
968
969 if (flags & O_DIRECTORY)
970 lookup_flags |= LOOKUP_DIRECTORY;
971 if (!(flags & O_NOFOLLOW))
972 lookup_flags |= LOOKUP_FOLLOW;
Al Virof9652e12013-06-11 08:23:01 +0400973 op->lookup_flags = lookup_flags;
974 return 0;
Al Viro47c805d2011-02-23 17:44:09 -0500975}
976
977/**
Jeff Layton669abf42012-10-10 16:43:10 -0400978 * file_open_name - open file and return file pointer
979 *
980 * @name: struct filename containing path to open
981 * @flags: open flags as per the open(2) second argument
982 * @mode: mode for the new file if O_CREAT is set, else ignored
983 *
984 * This is the helper to open a file from kernelspace if you really
985 * have to. But in generally you should not do this, so please move
986 * along, nothing to see here..
987 */
988struct file *file_open_name(struct filename *name, int flags, umode_t mode)
989{
990 struct open_flags op;
Al Virof9652e12013-06-11 08:23:01 +0400991 int err = build_open_flags(flags, mode, &op);
992 return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op);
Jeff Layton669abf42012-10-10 16:43:10 -0400993}
994
995/**
Al Viro47c805d2011-02-23 17:44:09 -0500996 * filp_open - open file and return file pointer
997 *
998 * @filename: path to open
999 * @flags: open flags as per the open(2) second argument
1000 * @mode: mode for the new file if O_CREAT is set, else ignored
1001 *
1002 * This is the helper to open a file from kernelspace if you really
1003 * have to. But in generally you should not do this, so please move
1004 * along, nothing to see here..
1005 */
Al Viroa218d0f2011-11-21 14:59:34 -05001006struct file *filp_open(const char *filename, int flags, umode_t mode)
Al Viro47c805d2011-02-23 17:44:09 -05001007{
Paul Moore51689102015-01-22 00:00:03 -05001008 struct filename *name = getname_kernel(filename);
1009 struct file *file = ERR_CAST(name);
1010
1011 if (!IS_ERR(name)) {
1012 file = file_open_name(name, flags, mode);
1013 putname(name);
1014 }
1015 return file;
Al Viro47c805d2011-02-23 17:44:09 -05001016}
1017EXPORT_SYMBOL(filp_open);
1018
Al Viro73d049a2011-03-11 12:08:24 -05001019struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
Jann Horn378c6522016-03-22 14:25:36 -07001020 const char *filename, int flags, umode_t mode)
Al Viro73d049a2011-03-11 12:08:24 -05001021{
1022 struct open_flags op;
Jann Horn378c6522016-03-22 14:25:36 -07001023 int err = build_open_flags(flags, mode, &op);
Al Virof9652e12013-06-11 08:23:01 +04001024 if (err)
1025 return ERR_PTR(err);
Al Virof9652e12013-06-11 08:23:01 +04001026 return do_file_open_root(dentry, mnt, filename, &op);
Al Viro73d049a2011-03-11 12:08:24 -05001027}
1028EXPORT_SYMBOL(file_open_root);
1029
James Bottomley9a08c352016-02-17 16:49:38 -08001030struct file *filp_clone_open(struct file *oldfile)
1031{
1032 struct file *file;
1033 int retval;
1034
1035 file = get_empty_filp();
1036 if (IS_ERR(file))
1037 return file;
1038
1039 file->f_flags = oldfile->f_flags;
1040 retval = vfs_open(&oldfile->f_path, file, oldfile->f_cred);
1041 if (retval) {
1042 put_filp(file);
1043 return ERR_PTR(retval);
1044 }
1045
1046 return file;
1047}
1048EXPORT_SYMBOL(filp_clone_open);
1049
Al Viroa218d0f2011-11-21 14:59:34 -05001050long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051{
Al Viro47c805d2011-02-23 17:44:09 -05001052 struct open_flags op;
Al Virof9652e12013-06-11 08:23:01 +04001053 int fd = build_open_flags(flags, mode, &op);
1054 struct filename *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055
Al Virof9652e12013-06-11 08:23:01 +04001056 if (fd)
1057 return fd;
1058
1059 tmp = getname(filename);
1060 if (IS_ERR(tmp))
1061 return PTR_ERR(tmp);
1062
1063 fd = get_unused_fd_flags(flags);
1064 if (fd >= 0) {
1065 struct file *f = do_filp_open(dfd, tmp, &op);
1066 if (IS_ERR(f)) {
1067 put_unused_fd(fd);
1068 fd = PTR_ERR(f);
1069 } else {
1070 fsnotify_open(f);
1071 fd_install(fd, f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 }
Al Virof9652e12013-06-11 08:23:01 +04001074 putname(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075 return fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076}
Miklos Szeredie922efc2005-09-06 15:18:25 -07001077
Al Viroa218d0f2011-11-21 14:59:34 -05001078SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
Miklos Szeredie922efc2005-09-06 15:18:25 -07001079{
1080 if (force_o_largefile())
1081 flags |= O_LARGEFILE;
1082
Al Viro2cf09662013-01-21 15:25:54 -05001083 return do_sys_open(AT_FDCWD, filename, flags, mode);
Miklos Szeredie922efc2005-09-06 15:18:25 -07001084}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085
Heiko Carstens6559eed82009-01-14 14:14:32 +01001086SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
Al Viroa218d0f2011-11-21 14:59:34 -05001087 umode_t, mode)
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001088{
1089 if (force_o_largefile())
1090 flags |= O_LARGEFILE;
1091
Al Viro2cf09662013-01-21 15:25:54 -05001092 return do_sys_open(dfd, filename, flags, mode);
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001093}
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001094
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095#ifndef __alpha__
1096
1097/*
1098 * For backward compatibility? Maybe this should be moved
1099 * into arch/i386 instead?
1100 */
Al Viroa218d0f2011-11-21 14:59:34 -05001101SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102{
1103 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1104}
1105
1106#endif
1107
1108/*
1109 * "id" is the POSIX thread ID. We use the
1110 * files pointer for this..
1111 */
1112int filp_close(struct file *filp, fl_owner_t id)
1113{
Christoph Lameter45778ca2005-06-23 00:10:17 -07001114 int retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115
1116 if (!file_count(filp)) {
1117 printk(KERN_ERR "VFS: Close: file count is 0\n");
Christoph Lameter45778ca2005-06-23 00:10:17 -07001118 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 }
1120
Al Viro72c2d532013-09-22 16:27:52 -04001121 if (filp->f_op->flush)
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -07001122 retval = filp->f_op->flush(filp, id);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123
Al Viro1abf0c72011-03-13 03:51:11 -04001124 if (likely(!(filp->f_mode & FMODE_PATH))) {
1125 dnotify_flush(filp, id);
1126 locks_remove_posix(filp, id);
1127 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128 fput(filp);
1129 return retval;
1130}
1131
1132EXPORT_SYMBOL(filp_close);
1133
1134/*
1135 * Careful here! We test whether the file pointer is NULL before
1136 * releasing the fd. This ensures that one clone task can't release
1137 * an fd while another clone is opening it.
1138 */
Heiko Carstensca013e92009-01-14 14:14:19 +01001139SYSCALL_DEFINE1(close, unsigned int, fd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140{
Al Viro483ce1d2012-08-19 12:04:24 -04001141 int retval = __close_fd(current->files, fd);
Ernie Petridesee731f42006-09-29 02:00:13 -07001142
1143 /* can't restart close syscall because file table entry was cleared */
1144 if (unlikely(retval == -ERESTARTSYS ||
1145 retval == -ERESTARTNOINTR ||
1146 retval == -ERESTARTNOHAND ||
1147 retval == -ERESTART_RESTARTBLOCK))
1148 retval = -EINTR;
1149
1150 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152EXPORT_SYMBOL(sys_close);
1153
1154/*
1155 * This routine simulates a hangup on the tty, to arrange that users
1156 * are given clean terminals at login time.
1157 */
Heiko Carstensca013e92009-01-14 14:14:19 +01001158SYSCALL_DEFINE0(vhangup)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159{
1160 if (capable(CAP_SYS_TTY_CONFIG)) {
Alan Cox2cb59982008-10-13 10:40:30 +01001161 tty_vhangup_self();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 return 0;
1163 }
1164 return -EPERM;
1165}
1166
1167/*
1168 * Called when an inode is about to be open.
1169 * We use this to disallow opening large files on 32bit systems if
1170 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1171 * on this flag in sys_open.
1172 */
1173int generic_file_open(struct inode * inode, struct file * filp)
1174{
1175 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
Alan Coxa9c62a12007-10-16 23:30:22 -07001176 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 return 0;
1178}
1179
1180EXPORT_SYMBOL(generic_file_open);
1181
1182/*
1183 * This is used by subsystems that don't want seekable
Dmitry Torokhov06b1e102010-08-10 18:01:33 -07001184 * file descriptors. The function is not supposed to ever fail, the only
1185 * reason it returns an 'int' and not 'void' is so that it can be plugged
1186 * directly into file_operations structure.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 */
1188int nonseekable_open(struct inode *inode, struct file *filp)
1189{
1190 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1191 return 0;
1192}
1193
1194EXPORT_SYMBOL(nonseekable_open);
Kirill Smelkov9c829b62019-03-26 22:20:43 +00001195
1196/*
1197 * stream_open is used by subsystems that want stream-like file descriptors.
1198 * Such file descriptors are not seekable and don't have notion of position
1199 * (file.f_pos is always 0). Contrary to file descriptors of other regular
1200 * files, .read() and .write() can run simultaneously.
1201 *
1202 * stream_open never fails and is marked to return int so that it could be
1203 * directly used as file_operations.open .
1204 */
1205int stream_open(struct inode *inode, struct file *filp)
1206{
1207 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS);
1208 filp->f_mode |= FMODE_STREAM;
1209 return 0;
1210}
1211
1212EXPORT_SYMBOL(stream_open);