blob: 4ea63ed5e79100d991e5f25656a263b04a29e611 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
22#include <linux/quotaops.h>
23#include <linux/pagemap.h>
Robert Love0eeca282005-07-12 17:06:03 -040024#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/personality.h>
26#include <linux/security.h>
27#include <linux/syscalls.h>
28#include <linux/mount.h>
29#include <linux/audit.h>
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080030#include <linux/capability.h>
Trond Myklebust834f2a42005-10-18 14:20:16 -070031#include <linux/file.h>
Ulrich Drepper5590ff02006-01-18 17:43:53 -080032#include <linux/fcntl.h>
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070033#include <linux/device_cgroup.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <asm/uaccess.h>
35
36#define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
37
38/* [Feb-1997 T. Schoebel-Theuer]
39 * Fundamental changes in the pathname lookup mechanisms (namei)
40 * were necessary because of omirr. The reason is that omirr needs
41 * to know the _real_ pathname, not the user-supplied one, in case
42 * of symlinks (and also when transname replacements occur).
43 *
44 * The new code replaces the old recursive symlink resolution with
45 * an iterative one (in case of non-nested symlink chains). It does
46 * this with calls to <fs>_follow_link().
47 * As a side effect, dir_namei(), _namei() and follow_link() are now
48 * replaced with a single function lookup_dentry() that can handle all
49 * the special cases of the former code.
50 *
51 * With the new dcache, the pathname is stored at each inode, at least as
52 * long as the refcount of the inode is positive. As a side effect, the
53 * size of the dcache depends on the inode cache and thus is dynamic.
54 *
55 * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink
56 * resolution to correspond with current state of the code.
57 *
58 * Note that the symlink resolution is not *completely* iterative.
59 * There is still a significant amount of tail- and mid- recursion in
60 * the algorithm. Also, note that <fs>_readlink() is not used in
61 * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink()
62 * may return different results than <fs>_follow_link(). Many virtual
63 * filesystems (including /proc) exhibit this behavior.
64 */
65
66/* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation:
67 * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL
68 * and the name already exists in form of a symlink, try to create the new
69 * name indicated by the symlink. The old code always complained that the
70 * name already exists, due to not following the symlink even if its target
71 * is nonexistent. The new semantics affects also mknod() and link() when
72 * the name is a symlink pointing to a non-existant name.
73 *
74 * I don't know which semantics is the right one, since I have no access
75 * to standards. But I found by trial that HP-UX 9.0 has the full "new"
76 * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the
77 * "old" one. Personally, I think the new semantics is much more logical.
78 * Note that "ln old new" where "new" is a symlink pointing to a non-existing
79 * file does succeed in both HP-UX and SunOs, but not in Solaris
80 * and in the old Linux semantics.
81 */
82
83/* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink
84 * semantics. See the comments in "open_namei" and "do_link" below.
85 *
86 * [10-Sep-98 Alan Modra] Another symlink change.
87 */
88
89/* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks:
90 * inside the path - always follow.
91 * in the last component in creation/removal/renaming - never follow.
92 * if LOOKUP_FOLLOW passed - follow.
93 * if the pathname has trailing slashes - follow.
94 * otherwise - don't follow.
95 * (applied in that order).
96 *
97 * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT
98 * restored for 2.4. This is the last surviving part of old 4.2BSD bug.
99 * During the 2.4 we need to fix the userland stuff depending on it -
100 * hopefully we will be able to get rid of that wart in 2.5. So far only
101 * XEmacs seems to be relying on it...
102 */
103/*
104 * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland)
Arjan van de Vena11f3a02006-03-23 03:00:33 -0800105 * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 * any extra contention...
107 */
108
Al Viroa02f76c2008-02-23 15:14:28 +0000109static int __link_path_walk(const char *name, struct nameidata *nd);
Josef 'Jeff' Sipekc4a78082007-07-19 01:48:22 -0700110
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111/* In order to reduce some races, while at the same time doing additional
112 * checking and hopefully speeding things up, we copy filenames to the
113 * kernel data space before using them..
114 *
115 * POSIX.1 2.4: an empty pathname is invalid (ENOENT).
116 * PATH_MAX includes the nul terminator --RR.
117 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800118static int do_getname(const char __user *filename, char *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119{
120 int retval;
121 unsigned long len = PATH_MAX;
122
123 if (!segment_eq(get_fs(), KERNEL_DS)) {
124 if ((unsigned long) filename >= TASK_SIZE)
125 return -EFAULT;
126 if (TASK_SIZE - (unsigned long) filename < PATH_MAX)
127 len = TASK_SIZE - (unsigned long) filename;
128 }
129
130 retval = strncpy_from_user(page, filename, len);
131 if (retval > 0) {
132 if (retval < len)
133 return 0;
134 return -ENAMETOOLONG;
135 } else if (!retval)
136 retval = -ENOENT;
137 return retval;
138}
139
140char * getname(const char __user * filename)
141{
142 char *tmp, *result;
143
144 result = ERR_PTR(-ENOMEM);
145 tmp = __getname();
146 if (tmp) {
147 int retval = do_getname(filename, tmp);
148
149 result = tmp;
150 if (retval < 0) {
151 __putname(tmp);
152 result = ERR_PTR(retval);
153 }
154 }
155 audit_getname(result);
156 return result;
157}
158
159#ifdef CONFIG_AUDITSYSCALL
160void putname(const char *name)
161{
Al Viro5ac3a9c2006-07-16 06:38:45 -0400162 if (unlikely(!audit_dummy_context()))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 audit_putname(name);
164 else
165 __putname(name);
166}
167EXPORT_SYMBOL(putname);
168#endif
169
170
171/**
172 * generic_permission - check for access rights on a Posix-like filesystem
173 * @inode: inode to check access rights for
174 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
175 * @check_acl: optional callback to check for Posix ACLs
176 *
177 * Used to check for read/write/execute permissions on a file.
178 * We use "fsuid" for this, letting us set arbitrary permissions
179 * for filesystem access without changing the "normal" uids which
180 * are used for other things..
181 */
182int generic_permission(struct inode *inode, int mask,
183 int (*check_acl)(struct inode *inode, int mask))
184{
185 umode_t mode = inode->i_mode;
186
Al Viroe6305c42008-07-15 21:03:57 -0400187 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
188
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 if (current->fsuid == inode->i_uid)
190 mode >>= 6;
191 else {
192 if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) {
193 int error = check_acl(inode, mask);
194 if (error == -EACCES)
195 goto check_capabilities;
196 else if (error != -EAGAIN)
197 return error;
198 }
199
200 if (in_group_p(inode->i_gid))
201 mode >>= 3;
202 }
203
204 /*
205 * If the DACs are ok we don't need any capability check.
206 */
Al Viroe6305c42008-07-15 21:03:57 -0400207 if ((mask & ~mode) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 return 0;
209
210 check_capabilities:
211 /*
212 * Read/write DACs are always overridable.
213 * Executable DACs are overridable if at least one exec bit is set.
214 */
215 if (!(mask & MAY_EXEC) ||
216 (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
217 if (capable(CAP_DAC_OVERRIDE))
218 return 0;
219
220 /*
221 * Searching includes executable on directories, else just read.
222 */
223 if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
224 if (capable(CAP_DAC_READ_SEARCH))
225 return 0;
226
227 return -EACCES;
228}
229
Al Virof419a2e2008-07-22 00:07:17 -0400230int inode_permission(struct inode *inode, int mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231{
Al Viroe6305c42008-07-15 21:03:57 -0400232 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
234 if (mask & MAY_WRITE) {
Miklos Szeredi22590e42007-10-16 23:27:08 -0700235 umode_t mode = inode->i_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
237 /*
238 * Nobody gets write access to a read-only fs.
239 */
240 if (IS_RDONLY(inode) &&
241 (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
242 return -EROFS;
243
244 /*
245 * Nobody gets write access to an immutable file.
246 */
247 if (IS_IMMUTABLE(inode))
248 return -EACCES;
249 }
250
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 /* Ordinary permission routines do not understand MAY_APPEND. */
Miklos Szeredi22590e42007-10-16 23:27:08 -0700252 if (inode->i_op && inode->i_op->permission) {
Al Virob77b0642008-07-17 09:37:02 -0400253 retval = inode->i_op->permission(inode, mask);
Miklos Szeredi22590e42007-10-16 23:27:08 -0700254 if (!retval) {
255 /*
256 * Exec permission on a regular file is denied if none
257 * of the execute bits are set.
258 *
259 * This check should be done by the ->permission()
260 * method.
261 */
262 if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode) &&
263 !(inode->i_mode & S_IXUGO))
264 return -EACCES;
265 }
266 } else {
Al Viroe6305c42008-07-15 21:03:57 -0400267 retval = generic_permission(inode, mask, NULL);
Miklos Szeredi22590e42007-10-16 23:27:08 -0700268 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 if (retval)
270 return retval;
271
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700272 retval = devcgroup_inode_permission(inode, mask);
273 if (retval)
274 return retval;
275
Al Viroe6305c42008-07-15 21:03:57 -0400276 return security_inode_permission(inode,
Stephen Smalleyf418b002008-07-28 13:32:38 -0400277 mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278}
279
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800280/**
281 * vfs_permission - check for access rights to a given path
282 * @nd: lookup result that describes the path
283 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
284 *
285 * Used to check for read/write/execute permissions on a path.
286 * We use "fsuid" for this, letting us set arbitrary permissions
287 * for filesystem access without changing the "normal" uids which
288 * are used for other things.
289 */
290int vfs_permission(struct nameidata *nd, int mask)
291{
Al Virof419a2e2008-07-22 00:07:17 -0400292 return inode_permission(nd->path.dentry->d_inode, mask);
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800293}
294
Christoph Hellwig8c744fb2005-11-08 21:35:04 -0800295/**
296 * file_permission - check for additional access rights to a given file
297 * @file: file to check access rights for
298 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
299 *
300 * Used to check for read/write/execute permissions on an already opened
301 * file.
302 *
303 * Note:
304 * Do not use this function in new code. All access checks should
305 * be done using vfs_permission().
306 */
307int file_permission(struct file *file, int mask)
308{
Al Virof419a2e2008-07-22 00:07:17 -0400309 return inode_permission(file->f_path.dentry->d_inode, mask);
Christoph Hellwig8c744fb2005-11-08 21:35:04 -0800310}
311
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312/*
313 * get_write_access() gets write permission for a file.
314 * put_write_access() releases this write permission.
315 * This is used for regular files.
316 * We cannot support write (and maybe mmap read-write shared) accesses and
317 * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
318 * can have the following values:
319 * 0: no writers, no VM_DENYWRITE mappings
320 * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
321 * > 0: (i_writecount) users are writing to the file.
322 *
323 * Normally we operate on that counter with atomic_{inc,dec} and it's safe
324 * except for the cases where we don't hold i_writecount yet. Then we need to
325 * use {get,deny}_write_access() - these functions check the sign and refuse
326 * to do the change if sign is wrong. Exclusion between them is provided by
327 * the inode->i_lock spinlock.
328 */
329
330int get_write_access(struct inode * inode)
331{
332 spin_lock(&inode->i_lock);
333 if (atomic_read(&inode->i_writecount) < 0) {
334 spin_unlock(&inode->i_lock);
335 return -ETXTBSY;
336 }
337 atomic_inc(&inode->i_writecount);
338 spin_unlock(&inode->i_lock);
339
340 return 0;
341}
342
343int deny_write_access(struct file * file)
344{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800345 struct inode *inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346
347 spin_lock(&inode->i_lock);
348 if (atomic_read(&inode->i_writecount) > 0) {
349 spin_unlock(&inode->i_lock);
350 return -ETXTBSY;
351 }
352 atomic_dec(&inode->i_writecount);
353 spin_unlock(&inode->i_lock);
354
355 return 0;
356}
357
Jan Blunck1d957f92008-02-14 19:34:35 -0800358/**
Jan Blunck5dd784d02008-02-14 19:34:38 -0800359 * path_get - get a reference to a path
360 * @path: path to get the reference to
361 *
362 * Given a path increment the reference count to the dentry and the vfsmount.
363 */
364void path_get(struct path *path)
365{
366 mntget(path->mnt);
367 dget(path->dentry);
368}
369EXPORT_SYMBOL(path_get);
370
371/**
Jan Blunck1d957f92008-02-14 19:34:35 -0800372 * path_put - put a reference to a path
373 * @path: path to put the reference to
374 *
375 * Given a path decrement the reference count to the dentry and the vfsmount.
376 */
377void path_put(struct path *path)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378{
Jan Blunck1d957f92008-02-14 19:34:35 -0800379 dput(path->dentry);
380 mntput(path->mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381}
Jan Blunck1d957f92008-02-14 19:34:35 -0800382EXPORT_SYMBOL(path_put);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383
Trond Myklebust834f2a42005-10-18 14:20:16 -0700384/**
385 * release_open_intent - free up open intent resources
386 * @nd: pointer to nameidata
387 */
388void release_open_intent(struct nameidata *nd)
389{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800390 if (nd->intent.open.file->f_path.dentry == NULL)
Trond Myklebust834f2a42005-10-18 14:20:16 -0700391 put_filp(nd->intent.open.file);
392 else
393 fput(nd->intent.open.file);
394}
395
Ian Kentbcdc5e02006-09-27 01:50:44 -0700396static inline struct dentry *
397do_revalidate(struct dentry *dentry, struct nameidata *nd)
398{
399 int status = dentry->d_op->d_revalidate(dentry, nd);
400 if (unlikely(status <= 0)) {
401 /*
402 * The dentry failed validation.
403 * If d_revalidate returned 0 attempt to invalidate
404 * the dentry otherwise d_revalidate is asking us
405 * to return a fail status.
406 */
407 if (!status) {
408 if (!d_invalidate(dentry)) {
409 dput(dentry);
410 dentry = NULL;
411 }
412 } else {
413 dput(dentry);
414 dentry = ERR_PTR(status);
415 }
416 }
417 return dentry;
418}
419
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420/*
421 * Internal lookup() using the new generic dcache.
422 * SMP-safe
423 */
424static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd)
425{
426 struct dentry * dentry = __d_lookup(parent, name);
427
428 /* lockess __d_lookup may fail due to concurrent d_move()
429 * in some unrelated directory, so try with d_lookup
430 */
431 if (!dentry)
432 dentry = d_lookup(parent, name);
433
Ian Kentbcdc5e02006-09-27 01:50:44 -0700434 if (dentry && dentry->d_op && dentry->d_op->d_revalidate)
435 dentry = do_revalidate(dentry, nd);
436
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 return dentry;
438}
439
440/*
441 * Short-cut version of permission(), for calling by
442 * path_walk(), when dcache lock is held. Combines parts
443 * of permission() and generic_permission(), and tests ONLY for
444 * MAY_EXEC permission.
445 *
446 * If appropriate, check DAC only. If not appropriate, or
447 * short-cut DAC fails, then call permission() to do more
448 * complete permission check.
449 */
Al Viro672b16b2008-07-17 09:45:01 -0400450static int exec_permission_lite(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451{
452 umode_t mode = inode->i_mode;
453
454 if (inode->i_op && inode->i_op->permission)
455 return -EAGAIN;
456
457 if (current->fsuid == inode->i_uid)
458 mode >>= 6;
459 else if (in_group_p(inode->i_gid))
460 mode >>= 3;
461
462 if (mode & MAY_EXEC)
463 goto ok;
464
465 if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE))
466 goto ok;
467
468 if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE))
469 goto ok;
470
471 if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH))
472 goto ok;
473
474 return -EACCES;
475ok:
Al Virob77b0642008-07-17 09:37:02 -0400476 return security_inode_permission(inode, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477}
478
479/*
480 * This is called when everything else fails, and we actually have
481 * to go to the low-level filesystem to find out what we should do..
482 *
483 * We get the directory semaphore, and after getting that we also
484 * make sure that nobody added the entry to the dcache in the meantime..
485 * SMP-safe
486 */
487static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd)
488{
489 struct dentry * result;
490 struct inode *dir = parent->d_inode;
491
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800492 mutex_lock(&dir->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 /*
494 * First re-do the cached lookup just in case it was created
495 * while we waited for the directory semaphore..
496 *
497 * FIXME! This could use version numbering or similar to
498 * avoid unnecessary cache lookups.
499 *
500 * The "dcache_lock" is purely to protect the RCU list walker
501 * from concurrent renames at this point (we mustn't get false
502 * negatives from the RCU list walk here, unlike the optimistic
503 * fast walk).
504 *
505 * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
506 */
507 result = d_lookup(parent, name);
508 if (!result) {
Miklos Szeredid70b67c2008-07-02 21:30:15 +0200509 struct dentry *dentry;
510
511 /* Don't create child dentry for a dead directory. */
512 result = ERR_PTR(-ENOENT);
513 if (IS_DEADDIR(dir))
514 goto out_unlock;
515
516 dentry = d_alloc(parent, name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 result = ERR_PTR(-ENOMEM);
518 if (dentry) {
519 result = dir->i_op->lookup(dir, dentry, nd);
520 if (result)
521 dput(dentry);
522 else
523 result = dentry;
524 }
Miklos Szeredid70b67c2008-07-02 21:30:15 +0200525out_unlock:
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800526 mutex_unlock(&dir->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 return result;
528 }
529
530 /*
531 * Uhhuh! Nasty case: the cache was re-populated while
532 * we waited on the semaphore. Need to revalidate.
533 */
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800534 mutex_unlock(&dir->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 if (result->d_op && result->d_op->d_revalidate) {
Ian Kentbcdc5e02006-09-27 01:50:44 -0700536 result = do_revalidate(result, nd);
537 if (!result)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 result = ERR_PTR(-ENOENT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 }
540 return result;
541}
542
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543/* SMP-safe */
Al Viro7f2da1e2008-05-10 20:44:54 -0400544static __always_inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545walk_init_root(const char *name, struct nameidata *nd)
546{
Andreas Mohre518ddb2006-09-29 02:01:22 -0700547 struct fs_struct *fs = current->fs;
548
549 read_lock(&fs->lock);
Jan Blunck6ac08c32008-02-14 19:34:38 -0800550 nd->path = fs->root;
551 path_get(&fs->root);
Andreas Mohre518ddb2006-09-29 02:01:22 -0700552 read_unlock(&fs->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553}
554
Al Viroa02f76c2008-02-23 15:14:28 +0000555/*
556 * Wrapper to retry pathname resolution whenever the underlying
557 * file system returns an ESTALE.
558 *
559 * Retry the whole path once, forcing real lookup requests
560 * instead of relying on the dcache.
561 */
562static __always_inline int link_path_walk(const char *name, struct nameidata *nd)
563{
564 struct path save = nd->path;
565 int result;
566
567 /* make sure the stuff we saved doesn't go away */
Jan Blunckc8e7f442008-06-09 16:40:35 -0700568 path_get(&save);
Al Viroa02f76c2008-02-23 15:14:28 +0000569
570 result = __link_path_walk(name, nd);
571 if (result == -ESTALE) {
572 /* nd->path had been dropped */
573 nd->path = save;
Jan Blunckc8e7f442008-06-09 16:40:35 -0700574 path_get(&nd->path);
Al Viroa02f76c2008-02-23 15:14:28 +0000575 nd->flags |= LOOKUP_REVAL;
576 result = __link_path_walk(name, nd);
577 }
578
579 path_put(&save);
580
581 return result;
582}
583
Arjan van de Venf1662352006-01-14 13:21:31 -0800584static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585{
586 int res = 0;
587 char *name;
588 if (IS_ERR(link))
589 goto fail;
590
591 if (*link == '/') {
Jan Blunck1d957f92008-02-14 19:34:35 -0800592 path_put(&nd->path);
Al Viro7f2da1e2008-05-10 20:44:54 -0400593 walk_init_root(link, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 }
595 res = link_path_walk(link, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 if (nd->depth || res || nd->last_type!=LAST_NORM)
597 return res;
598 /*
599 * If it is an iterative symlinks resolution in open_namei() we
600 * have to copy the last component. And all that crap because of
601 * bloody create() on broken symlinks. Furrfu...
602 */
603 name = __getname();
604 if (unlikely(!name)) {
Jan Blunck1d957f92008-02-14 19:34:35 -0800605 path_put(&nd->path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 return -ENOMEM;
607 }
608 strcpy(name, nd->last.name);
609 nd->last.name = name;
610 return 0;
611fail:
Jan Blunck1d957f92008-02-14 19:34:35 -0800612 path_put(&nd->path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 return PTR_ERR(link);
614}
615
Jan Blunck1d957f92008-02-14 19:34:35 -0800616static void path_put_conditional(struct path *path, struct nameidata *nd)
Miklos Szeredi09dd17d2005-09-06 15:18:21 -0700617{
618 dput(path->dentry);
Jan Blunck4ac91372008-02-14 19:34:32 -0800619 if (path->mnt != nd->path.mnt)
Miklos Szeredi09dd17d2005-09-06 15:18:21 -0700620 mntput(path->mnt);
621}
622
623static inline void path_to_nameidata(struct path *path, struct nameidata *nd)
624{
Jan Blunck4ac91372008-02-14 19:34:32 -0800625 dput(nd->path.dentry);
626 if (nd->path.mnt != path->mnt)
627 mntput(nd->path.mnt);
628 nd->path.mnt = path->mnt;
629 nd->path.dentry = path->dentry;
Miklos Szeredi09dd17d2005-09-06 15:18:21 -0700630}
631
Ian Kent051d3812006-03-27 01:14:53 -0800632static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd)
633{
634 int error;
635 void *cookie;
636 struct dentry *dentry = path->dentry;
637
638 touch_atime(path->mnt, dentry);
639 nd_set_link(nd, NULL);
640
Jan Blunck4ac91372008-02-14 19:34:32 -0800641 if (path->mnt != nd->path.mnt) {
Ian Kent051d3812006-03-27 01:14:53 -0800642 path_to_nameidata(path, nd);
643 dget(dentry);
644 }
645 mntget(path->mnt);
646 cookie = dentry->d_inode->i_op->follow_link(dentry, nd);
647 error = PTR_ERR(cookie);
648 if (!IS_ERR(cookie)) {
649 char *s = nd_get_link(nd);
650 error = 0;
651 if (s)
652 error = __vfs_follow_link(nd, s);
653 if (dentry->d_inode->i_op->put_link)
654 dentry->d_inode->i_op->put_link(dentry, nd, cookie);
655 }
Jan Blunck09da59162008-02-14 19:34:37 -0800656 path_put(path);
Ian Kent051d3812006-03-27 01:14:53 -0800657
658 return error;
659}
660
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661/*
662 * This limits recursive symlink follows to 8, while
663 * limiting consecutive symlinks to 40.
664 *
665 * Without that kind of total limit, nasty chains of consecutive
666 * symlinks can cause almost arbitrarily long lookups.
667 */
Al Viro90ebe562005-06-06 13:35:58 -0700668static inline int do_follow_link(struct path *path, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669{
670 int err = -ELOOP;
671 if (current->link_count >= MAX_NESTED_LINKS)
672 goto loop;
673 if (current->total_link_count >= 40)
674 goto loop;
675 BUG_ON(nd->depth >= MAX_NESTED_LINKS);
676 cond_resched();
Al Viro90ebe562005-06-06 13:35:58 -0700677 err = security_inode_follow_link(path->dentry, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 if (err)
679 goto loop;
680 current->link_count++;
681 current->total_link_count++;
682 nd->depth++;
Al Virocd4e91d2005-06-06 13:36:03 -0700683 err = __do_follow_link(path, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 current->link_count--;
685 nd->depth--;
686 return err;
687loop:
Jan Blunck1d957f92008-02-14 19:34:35 -0800688 path_put_conditional(path, nd);
689 path_put(&nd->path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 return err;
691}
692
693int follow_up(struct vfsmount **mnt, struct dentry **dentry)
694{
695 struct vfsmount *parent;
696 struct dentry *mountpoint;
697 spin_lock(&vfsmount_lock);
698 parent=(*mnt)->mnt_parent;
699 if (parent == *mnt) {
700 spin_unlock(&vfsmount_lock);
701 return 0;
702 }
703 mntget(parent);
704 mountpoint=dget((*mnt)->mnt_mountpoint);
705 spin_unlock(&vfsmount_lock);
706 dput(*dentry);
707 *dentry = mountpoint;
708 mntput(*mnt);
709 *mnt = parent;
710 return 1;
711}
712
713/* no need for dcache_lock, as serialization is taken care in
714 * namespace.c
715 */
Al Viro463ffb22005-06-06 13:36:05 -0700716static int __follow_mount(struct path *path)
717{
718 int res = 0;
719 while (d_mountpoint(path->dentry)) {
720 struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry);
721 if (!mounted)
722 break;
723 dput(path->dentry);
724 if (res)
725 mntput(path->mnt);
726 path->mnt = mounted;
727 path->dentry = dget(mounted->mnt_root);
728 res = 1;
729 }
730 return res;
731}
732
Al Viro58c465e2005-06-06 13:36:13 -0700733static void follow_mount(struct vfsmount **mnt, struct dentry **dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 while (d_mountpoint(*dentry)) {
736 struct vfsmount *mounted = lookup_mnt(*mnt, *dentry);
737 if (!mounted)
738 break;
Al Viro58c465e2005-06-06 13:36:13 -0700739 dput(*dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 mntput(*mnt);
741 *mnt = mounted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 *dentry = dget(mounted->mnt_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744}
745
746/* no need for dcache_lock, as serialization is taken care in
747 * namespace.c
748 */
Al Viroe13b2102005-06-06 13:36:06 -0700749int follow_down(struct vfsmount **mnt, struct dentry **dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750{
751 struct vfsmount *mounted;
752
753 mounted = lookup_mnt(*mnt, *dentry);
754 if (mounted) {
Al Viroe13b2102005-06-06 13:36:06 -0700755 dput(*dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 mntput(*mnt);
757 *mnt = mounted;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 *dentry = dget(mounted->mnt_root);
759 return 1;
760 }
761 return 0;
762}
763
Arjan van de Venf1662352006-01-14 13:21:31 -0800764static __always_inline void follow_dotdot(struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765{
Andreas Mohre518ddb2006-09-29 02:01:22 -0700766 struct fs_struct *fs = current->fs;
767
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 while(1) {
769 struct vfsmount *parent;
Jan Blunck4ac91372008-02-14 19:34:32 -0800770 struct dentry *old = nd->path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771
Andreas Mohre518ddb2006-09-29 02:01:22 -0700772 read_lock(&fs->lock);
Jan Blunck6ac08c32008-02-14 19:34:38 -0800773 if (nd->path.dentry == fs->root.dentry &&
774 nd->path.mnt == fs->root.mnt) {
Andreas Mohre518ddb2006-09-29 02:01:22 -0700775 read_unlock(&fs->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 break;
777 }
Andreas Mohre518ddb2006-09-29 02:01:22 -0700778 read_unlock(&fs->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 spin_lock(&dcache_lock);
Jan Blunck4ac91372008-02-14 19:34:32 -0800780 if (nd->path.dentry != nd->path.mnt->mnt_root) {
781 nd->path.dentry = dget(nd->path.dentry->d_parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 spin_unlock(&dcache_lock);
783 dput(old);
784 break;
785 }
786 spin_unlock(&dcache_lock);
787 spin_lock(&vfsmount_lock);
Jan Blunck4ac91372008-02-14 19:34:32 -0800788 parent = nd->path.mnt->mnt_parent;
789 if (parent == nd->path.mnt) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 spin_unlock(&vfsmount_lock);
791 break;
792 }
793 mntget(parent);
Jan Blunck4ac91372008-02-14 19:34:32 -0800794 nd->path.dentry = dget(nd->path.mnt->mnt_mountpoint);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 spin_unlock(&vfsmount_lock);
796 dput(old);
Jan Blunck4ac91372008-02-14 19:34:32 -0800797 mntput(nd->path.mnt);
798 nd->path.mnt = parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 }
Jan Blunck4ac91372008-02-14 19:34:32 -0800800 follow_mount(&nd->path.mnt, &nd->path.dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801}
802
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803/*
804 * It's more convoluted than I'd like it to be, but... it's still fairly
805 * small and for now I'd prefer to have fast path as straight as possible.
806 * It _is_ time-critical.
807 */
808static int do_lookup(struct nameidata *nd, struct qstr *name,
809 struct path *path)
810{
Jan Blunck4ac91372008-02-14 19:34:32 -0800811 struct vfsmount *mnt = nd->path.mnt;
812 struct dentry *dentry = __d_lookup(nd->path.dentry, name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813
814 if (!dentry)
815 goto need_lookup;
816 if (dentry->d_op && dentry->d_op->d_revalidate)
817 goto need_revalidate;
818done:
819 path->mnt = mnt;
820 path->dentry = dentry;
Al Viro634ee702005-06-06 13:36:13 -0700821 __follow_mount(path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 return 0;
823
824need_lookup:
Jan Blunck4ac91372008-02-14 19:34:32 -0800825 dentry = real_lookup(nd->path.dentry, name, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 if (IS_ERR(dentry))
827 goto fail;
828 goto done;
829
830need_revalidate:
Ian Kentbcdc5e02006-09-27 01:50:44 -0700831 dentry = do_revalidate(dentry, nd);
832 if (!dentry)
833 goto need_lookup;
834 if (IS_ERR(dentry))
835 goto fail;
836 goto done;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837
838fail:
839 return PTR_ERR(dentry);
840}
841
842/*
843 * Name resolution.
Prasanna Medaea3834d2005-04-29 16:00:17 +0100844 * This is the basic name resolution function, turning a pathname into
845 * the final dentry. We expect 'base' to be positive and a directory.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 *
Prasanna Medaea3834d2005-04-29 16:00:17 +0100847 * Returns 0 and nd will have valid dentry and mnt on success.
848 * Returns error and drops reference to input namei data on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -0800850static int __link_path_walk(const char *name, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851{
852 struct path next;
853 struct inode *inode;
854 int err;
855 unsigned int lookup_flags = nd->flags;
856
857 while (*name=='/')
858 name++;
859 if (!*name)
860 goto return_reval;
861
Jan Blunck4ac91372008-02-14 19:34:32 -0800862 inode = nd->path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 if (nd->depth)
Trond Myklebustf55eab82006-02-04 23:28:01 -0800864 lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865
866 /* At this point we know we have a real path component. */
867 for(;;) {
868 unsigned long hash;
869 struct qstr this;
870 unsigned int c;
871
Trond Myklebustcdce5d62005-10-18 14:20:18 -0700872 nd->flags |= LOOKUP_CONTINUE;
Al Viro672b16b2008-07-17 09:45:01 -0400873 err = exec_permission_lite(inode);
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800874 if (err == -EAGAIN)
875 err = vfs_permission(nd, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 if (err)
877 break;
878
879 this.name = name;
880 c = *(const unsigned char *)name;
881
882 hash = init_name_hash();
883 do {
884 name++;
885 hash = partial_name_hash(c, hash);
886 c = *(const unsigned char *)name;
887 } while (c && (c != '/'));
888 this.len = name - (const char *) this.name;
889 this.hash = end_name_hash(hash);
890
891 /* remove trailing slashes? */
892 if (!c)
893 goto last_component;
894 while (*++name == '/');
895 if (!*name)
896 goto last_with_slashes;
897
898 /*
899 * "." and ".." are special - ".." especially so because it has
900 * to be able to know about the current root directory and
901 * parent relationships.
902 */
903 if (this.name[0] == '.') switch (this.len) {
904 default:
905 break;
906 case 2:
907 if (this.name[1] != '.')
908 break;
Al Viro58c465e2005-06-06 13:36:13 -0700909 follow_dotdot(nd);
Jan Blunck4ac91372008-02-14 19:34:32 -0800910 inode = nd->path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 /* fallthrough */
912 case 1:
913 continue;
914 }
915 /*
916 * See if the low-level filesystem might want
917 * to use its own hash..
918 */
Jan Blunck4ac91372008-02-14 19:34:32 -0800919 if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) {
920 err = nd->path.dentry->d_op->d_hash(nd->path.dentry,
921 &this);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 if (err < 0)
923 break;
924 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925 /* This does the actual lookups.. */
926 err = do_lookup(nd, &this, &next);
927 if (err)
928 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929
930 err = -ENOENT;
931 inode = next.dentry->d_inode;
932 if (!inode)
933 goto out_dput;
934 err = -ENOTDIR;
935 if (!inode->i_op)
936 goto out_dput;
937
938 if (inode->i_op->follow_link) {
Al Viro90ebe562005-06-06 13:35:58 -0700939 err = do_follow_link(&next, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700940 if (err)
941 goto return_err;
942 err = -ENOENT;
Jan Blunck4ac91372008-02-14 19:34:32 -0800943 inode = nd->path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944 if (!inode)
945 break;
946 err = -ENOTDIR;
947 if (!inode->i_op)
948 break;
Miklos Szeredi09dd17d2005-09-06 15:18:21 -0700949 } else
950 path_to_nameidata(&next, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 err = -ENOTDIR;
952 if (!inode->i_op->lookup)
953 break;
954 continue;
955 /* here ends the main loop */
956
957last_with_slashes:
958 lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
959last_component:
Trond Myklebustf55eab82006-02-04 23:28:01 -0800960 /* Clear LOOKUP_CONTINUE iff it was previously unset */
961 nd->flags &= lookup_flags | ~LOOKUP_CONTINUE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 if (lookup_flags & LOOKUP_PARENT)
963 goto lookup_parent;
964 if (this.name[0] == '.') switch (this.len) {
965 default:
966 break;
967 case 2:
968 if (this.name[1] != '.')
969 break;
Al Viro58c465e2005-06-06 13:36:13 -0700970 follow_dotdot(nd);
Jan Blunck4ac91372008-02-14 19:34:32 -0800971 inode = nd->path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 /* fallthrough */
973 case 1:
974 goto return_reval;
975 }
Jan Blunck4ac91372008-02-14 19:34:32 -0800976 if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) {
977 err = nd->path.dentry->d_op->d_hash(nd->path.dentry,
978 &this);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979 if (err < 0)
980 break;
981 }
982 err = do_lookup(nd, &this, &next);
983 if (err)
984 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 inode = next.dentry->d_inode;
986 if ((lookup_flags & LOOKUP_FOLLOW)
987 && inode && inode->i_op && inode->i_op->follow_link) {
Al Viro90ebe562005-06-06 13:35:58 -0700988 err = do_follow_link(&next, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 if (err)
990 goto return_err;
Jan Blunck4ac91372008-02-14 19:34:32 -0800991 inode = nd->path.dentry->d_inode;
Miklos Szeredi09dd17d2005-09-06 15:18:21 -0700992 } else
993 path_to_nameidata(&next, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 err = -ENOENT;
995 if (!inode)
996 break;
997 if (lookup_flags & LOOKUP_DIRECTORY) {
998 err = -ENOTDIR;
999 if (!inode->i_op || !inode->i_op->lookup)
1000 break;
1001 }
1002 goto return_base;
1003lookup_parent:
1004 nd->last = this;
1005 nd->last_type = LAST_NORM;
1006 if (this.name[0] != '.')
1007 goto return_base;
1008 if (this.len == 1)
1009 nd->last_type = LAST_DOT;
1010 else if (this.len == 2 && this.name[1] == '.')
1011 nd->last_type = LAST_DOTDOT;
1012 else
1013 goto return_base;
1014return_reval:
1015 /*
1016 * We bypassed the ordinary revalidation routines.
1017 * We may need to check the cached dentry for staleness.
1018 */
Jan Blunck4ac91372008-02-14 19:34:32 -08001019 if (nd->path.dentry && nd->path.dentry->d_sb &&
1020 (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 err = -ESTALE;
1022 /* Note: we do not d_invalidate() */
Jan Blunck4ac91372008-02-14 19:34:32 -08001023 if (!nd->path.dentry->d_op->d_revalidate(
1024 nd->path.dentry, nd))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 break;
1026 }
1027return_base:
1028 return 0;
1029out_dput:
Jan Blunck1d957f92008-02-14 19:34:35 -08001030 path_put_conditional(&next, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 break;
1032 }
Jan Blunck1d957f92008-02-14 19:34:35 -08001033 path_put(&nd->path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034return_err:
1035 return err;
1036}
1037
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -08001038static int path_walk(const char *name, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039{
1040 current->total_link_count = 0;
1041 return link_path_walk(name, nd);
1042}
1043
Prasanna Medaea3834d2005-04-29 16:00:17 +01001044/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -08001045static int do_path_lookup(int dfd, const char *name,
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001046 unsigned int flags, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047{
Prasanna Medaea3834d2005-04-29 16:00:17 +01001048 int retval = 0;
Ulrich Drepper170aa3d2006-02-04 23:28:02 -08001049 int fput_needed;
1050 struct file *file;
Andreas Mohre518ddb2006-09-29 02:01:22 -07001051 struct fs_struct *fs = current->fs;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052
1053 nd->last_type = LAST_ROOT; /* if there are only slashes... */
1054 nd->flags = flags;
1055 nd->depth = 0;
1056
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057 if (*name=='/') {
Andreas Mohre518ddb2006-09-29 02:01:22 -07001058 read_lock(&fs->lock);
Jan Blunck6ac08c32008-02-14 19:34:38 -08001059 nd->path = fs->root;
1060 path_get(&fs->root);
Andreas Mohre518ddb2006-09-29 02:01:22 -07001061 read_unlock(&fs->lock);
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001062 } else if (dfd == AT_FDCWD) {
Andreas Mohre518ddb2006-09-29 02:01:22 -07001063 read_lock(&fs->lock);
Jan Blunck6ac08c32008-02-14 19:34:38 -08001064 nd->path = fs->pwd;
1065 path_get(&fs->pwd);
Andreas Mohre518ddb2006-09-29 02:01:22 -07001066 read_unlock(&fs->lock);
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001067 } else {
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001068 struct dentry *dentry;
1069
1070 file = fget_light(dfd, &fput_needed);
Ulrich Drepper170aa3d2006-02-04 23:28:02 -08001071 retval = -EBADF;
1072 if (!file)
Trond Myklebust6d09bb62006-06-04 02:51:37 -07001073 goto out_fail;
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001074
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001075 dentry = file->f_path.dentry;
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001076
Ulrich Drepper170aa3d2006-02-04 23:28:02 -08001077 retval = -ENOTDIR;
1078 if (!S_ISDIR(dentry->d_inode->i_mode))
Trond Myklebust6d09bb62006-06-04 02:51:37 -07001079 goto fput_fail;
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001080
1081 retval = file_permission(file, MAY_EXEC);
Ulrich Drepper170aa3d2006-02-04 23:28:02 -08001082 if (retval)
Trond Myklebust6d09bb62006-06-04 02:51:37 -07001083 goto fput_fail;
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001084
Jan Blunck5dd784d02008-02-14 19:34:38 -08001085 nd->path = file->f_path;
1086 path_get(&file->f_path);
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001087
1088 fput_light(file, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 }
Josef 'Jeff' Sipek2dfdd262007-05-09 02:33:41 -07001090
1091 retval = path_walk(name, nd);
Jan Blunck4ac91372008-02-14 19:34:32 -08001092 if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
1093 nd->path.dentry->d_inode))
1094 audit_inode(name, nd->path.dentry);
Trond Myklebust6d09bb62006-06-04 02:51:37 -07001095out_fail:
Ulrich Drepper170aa3d2006-02-04 23:28:02 -08001096 return retval;
1097
Trond Myklebust6d09bb62006-06-04 02:51:37 -07001098fput_fail:
Ulrich Drepper170aa3d2006-02-04 23:28:02 -08001099 fput_light(file, fput_needed);
Trond Myklebust6d09bb62006-06-04 02:51:37 -07001100 goto out_fail;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101}
1102
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -08001103int path_lookup(const char *name, unsigned int flags,
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001104 struct nameidata *nd)
1105{
1106 return do_path_lookup(AT_FDCWD, name, flags, nd);
1107}
1108
Josef 'Jeff' Sipek16f18202007-07-19 01:48:18 -07001109/**
1110 * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
1111 * @dentry: pointer to dentry of the base directory
1112 * @mnt: pointer to vfs mount of the base directory
1113 * @name: pointer to file name
1114 * @flags: lookup flags
1115 * @nd: pointer to nameidata
1116 */
1117int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
1118 const char *name, unsigned int flags,
1119 struct nameidata *nd)
1120{
1121 int retval;
1122
1123 /* same as do_path_lookup */
1124 nd->last_type = LAST_ROOT;
1125 nd->flags = flags;
1126 nd->depth = 0;
1127
Jan Blunckc8e7f442008-06-09 16:40:35 -07001128 nd->path.dentry = dentry;
1129 nd->path.mnt = mnt;
1130 path_get(&nd->path);
Josef 'Jeff' Sipek16f18202007-07-19 01:48:18 -07001131
1132 retval = path_walk(name, nd);
Jan Blunck4ac91372008-02-14 19:34:32 -08001133 if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
1134 nd->path.dentry->d_inode))
1135 audit_inode(name, nd->path.dentry);
Josef 'Jeff' Sipek16f18202007-07-19 01:48:18 -07001136
1137 return retval;
1138
1139}
1140
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001141static int __path_lookup_intent_open(int dfd, const char *name,
1142 unsigned int lookup_flags, struct nameidata *nd,
1143 int open_flags, int create_mode)
Trond Myklebust834f2a42005-10-18 14:20:16 -07001144{
1145 struct file *filp = get_empty_filp();
1146 int err;
1147
1148 if (filp == NULL)
1149 return -ENFILE;
1150 nd->intent.open.file = filp;
1151 nd->intent.open.flags = open_flags;
1152 nd->intent.open.create_mode = create_mode;
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001153 err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd);
Trond Myklebust834f2a42005-10-18 14:20:16 -07001154 if (IS_ERR(nd->intent.open.file)) {
1155 if (err == 0) {
1156 err = PTR_ERR(nd->intent.open.file);
Jan Blunck1d957f92008-02-14 19:34:35 -08001157 path_put(&nd->path);
Trond Myklebust834f2a42005-10-18 14:20:16 -07001158 }
1159 } else if (err != 0)
1160 release_open_intent(nd);
1161 return err;
1162}
1163
1164/**
1165 * path_lookup_open - lookup a file path with open intent
Martin Waitz7045f372006-02-01 03:06:57 -08001166 * @dfd: the directory to use as base, or AT_FDCWD
Trond Myklebust834f2a42005-10-18 14:20:16 -07001167 * @name: pointer to file name
1168 * @lookup_flags: lookup intent flags
1169 * @nd: pointer to nameidata
1170 * @open_flags: open intent flags
1171 */
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001172int path_lookup_open(int dfd, const char *name, unsigned int lookup_flags,
Trond Myklebust834f2a42005-10-18 14:20:16 -07001173 struct nameidata *nd, int open_flags)
1174{
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001175 return __path_lookup_intent_open(dfd, name, lookup_flags, nd,
Trond Myklebust834f2a42005-10-18 14:20:16 -07001176 open_flags, 0);
1177}
1178
1179/**
1180 * path_lookup_create - lookup a file path with open + create intent
Martin Waitz7045f372006-02-01 03:06:57 -08001181 * @dfd: the directory to use as base, or AT_FDCWD
Trond Myklebust834f2a42005-10-18 14:20:16 -07001182 * @name: pointer to file name
1183 * @lookup_flags: lookup intent flags
1184 * @nd: pointer to nameidata
1185 * @open_flags: open intent flags
1186 * @create_mode: create intent flags
1187 */
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001188static int path_lookup_create(int dfd, const char *name,
1189 unsigned int lookup_flags, struct nameidata *nd,
1190 int open_flags, int create_mode)
Trond Myklebust834f2a42005-10-18 14:20:16 -07001191{
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001192 return __path_lookup_intent_open(dfd, name, lookup_flags|LOOKUP_CREATE,
1193 nd, open_flags, create_mode);
Trond Myklebust834f2a42005-10-18 14:20:16 -07001194}
1195
Christoph Hellwigeead1912007-10-16 23:25:38 -07001196static struct dentry *__lookup_hash(struct qstr *name,
1197 struct dentry *base, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198{
James Morris057f6c02007-04-26 00:12:05 -07001199 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 struct inode *inode;
1201 int err;
1202
1203 inode = base->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204
1205 /*
1206 * See if the low-level filesystem might want
1207 * to use its own hash..
1208 */
1209 if (base->d_op && base->d_op->d_hash) {
1210 err = base->d_op->d_hash(base, name);
1211 dentry = ERR_PTR(err);
1212 if (err < 0)
1213 goto out;
1214 }
1215
1216 dentry = cached_lookup(base, name, nd);
1217 if (!dentry) {
Miklos Szeredid70b67c2008-07-02 21:30:15 +02001218 struct dentry *new;
1219
1220 /* Don't create child dentry for a dead directory. */
1221 dentry = ERR_PTR(-ENOENT);
1222 if (IS_DEADDIR(inode))
1223 goto out;
1224
1225 new = d_alloc(base, name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226 dentry = ERR_PTR(-ENOMEM);
1227 if (!new)
1228 goto out;
1229 dentry = inode->i_op->lookup(inode, new, nd);
1230 if (!dentry)
1231 dentry = new;
1232 else
1233 dput(new);
1234 }
1235out:
1236 return dentry;
1237}
1238
James Morris057f6c02007-04-26 00:12:05 -07001239/*
1240 * Restricted form of lookup. Doesn't follow links, single-component only,
1241 * needs parent already locked. Doesn't follow mounts.
1242 * SMP-safe.
1243 */
Adrian Bunka244e162006-03-31 02:32:11 -08001244static struct dentry *lookup_hash(struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245{
Christoph Hellwigeead1912007-10-16 23:25:38 -07001246 int err;
1247
Al Virof419a2e2008-07-22 00:07:17 -04001248 err = inode_permission(nd->path.dentry->d_inode, MAY_EXEC);
Christoph Hellwigeead1912007-10-16 23:25:38 -07001249 if (err)
1250 return ERR_PTR(err);
Jan Blunck4ac91372008-02-14 19:34:32 -08001251 return __lookup_hash(&nd->last, nd->path.dentry, nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252}
1253
Christoph Hellwigeead1912007-10-16 23:25:38 -07001254static int __lookup_one_len(const char *name, struct qstr *this,
1255 struct dentry *base, int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256{
1257 unsigned long hash;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258 unsigned int c;
1259
James Morris057f6c02007-04-26 00:12:05 -07001260 this->name = name;
1261 this->len = len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 if (!len)
James Morris057f6c02007-04-26 00:12:05 -07001263 return -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264
1265 hash = init_name_hash();
1266 while (len--) {
1267 c = *(const unsigned char *)name++;
1268 if (c == '/' || c == '\0')
James Morris057f6c02007-04-26 00:12:05 -07001269 return -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 hash = partial_name_hash(c, hash);
1271 }
James Morris057f6c02007-04-26 00:12:05 -07001272 this->hash = end_name_hash(hash);
1273 return 0;
1274}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275
Christoph Hellwigeead1912007-10-16 23:25:38 -07001276/**
Randy Dunlapa6b91912008-03-19 17:01:00 -07001277 * lookup_one_len - filesystem helper to lookup single pathname component
Christoph Hellwigeead1912007-10-16 23:25:38 -07001278 * @name: pathname component to lookup
1279 * @base: base directory to lookup from
1280 * @len: maximum length @len should be interpreted to
1281 *
Randy Dunlapa6b91912008-03-19 17:01:00 -07001282 * Note that this routine is purely a helper for filesystem usage and should
1283 * not be called by generic code. Also note that by using this function the
Christoph Hellwigeead1912007-10-16 23:25:38 -07001284 * nameidata argument is passed to the filesystem methods and a filesystem
1285 * using this helper needs to be prepared for that.
1286 */
James Morris057f6c02007-04-26 00:12:05 -07001287struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
1288{
1289 int err;
1290 struct qstr this;
1291
1292 err = __lookup_one_len(name, &this, base, len);
1293 if (err)
1294 return ERR_PTR(err);
Christoph Hellwigeead1912007-10-16 23:25:38 -07001295
Al Virof419a2e2008-07-22 00:07:17 -04001296 err = inode_permission(base->d_inode, MAY_EXEC);
Christoph Hellwigeead1912007-10-16 23:25:38 -07001297 if (err)
1298 return ERR_PTR(err);
Christoph Hellwig49705b72005-11-08 21:35:06 -08001299 return __lookup_hash(&this, base, NULL);
James Morris057f6c02007-04-26 00:12:05 -07001300}
1301
Christoph Hellwigeead1912007-10-16 23:25:38 -07001302/**
1303 * lookup_one_noperm - bad hack for sysfs
1304 * @name: pathname component to lookup
1305 * @base: base directory to lookup from
1306 *
1307 * This is a variant of lookup_one_len that doesn't perform any permission
1308 * checks. It's a horrible hack to work around the braindead sysfs
1309 * architecture and should not be used anywhere else.
1310 *
1311 * DON'T USE THIS FUNCTION EVER, thanks.
1312 */
1313struct dentry *lookup_one_noperm(const char *name, struct dentry *base)
James Morris057f6c02007-04-26 00:12:05 -07001314{
1315 int err;
1316 struct qstr this;
1317
Christoph Hellwigeead1912007-10-16 23:25:38 -07001318 err = __lookup_one_len(name, &this, base, strlen(name));
James Morris057f6c02007-04-26 00:12:05 -07001319 if (err)
1320 return ERR_PTR(err);
Christoph Hellwigeead1912007-10-16 23:25:38 -07001321 return __lookup_hash(&this, base, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322}
1323
Al Viro2d8f3032008-07-22 09:59:21 -04001324int user_path_at(int dfd, const char __user *name, unsigned flags,
1325 struct path *path)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001326{
Al Viro2d8f3032008-07-22 09:59:21 -04001327 struct nameidata nd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 char *tmp = getname(name);
1329 int err = PTR_ERR(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 if (!IS_ERR(tmp)) {
Al Viro2d8f3032008-07-22 09:59:21 -04001331
1332 BUG_ON(flags & LOOKUP_PARENT);
1333
1334 err = do_path_lookup(dfd, tmp, flags, &nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 putname(tmp);
Al Viro2d8f3032008-07-22 09:59:21 -04001336 if (!err)
1337 *path = nd.path;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 }
1339 return err;
1340}
1341
Al Viro2ad94ae2008-07-21 09:32:51 -04001342static int user_path_parent(int dfd, const char __user *path,
1343 struct nameidata *nd, char **name)
1344{
1345 char *s = getname(path);
1346 int error;
1347
1348 if (IS_ERR(s))
1349 return PTR_ERR(s);
1350
1351 error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd);
1352 if (error)
1353 putname(s);
1354 else
1355 *name = s;
1356
1357 return error;
1358}
1359
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360/*
1361 * It's inline, so penalty for filesystems that don't use sticky bit is
1362 * minimal.
1363 */
1364static inline int check_sticky(struct inode *dir, struct inode *inode)
1365{
1366 if (!(dir->i_mode & S_ISVTX))
1367 return 0;
1368 if (inode->i_uid == current->fsuid)
1369 return 0;
1370 if (dir->i_uid == current->fsuid)
1371 return 0;
1372 return !capable(CAP_FOWNER);
1373}
1374
1375/*
1376 * Check whether we can remove a link victim from directory dir, check
1377 * whether the type of victim is right.
1378 * 1. We can't do it if dir is read-only (done in permission())
1379 * 2. We should have write and exec permissions on dir
1380 * 3. We can't remove anything from append-only dir
1381 * 4. We can't do anything with immutable dir (done in permission())
1382 * 5. If the sticky bit on dir is set we should either
1383 * a. be owner of dir, or
1384 * b. be owner of victim, or
1385 * c. have CAP_FOWNER capability
1386 * 6. If the victim is append-only or immutable we can't do antyhing with
1387 * links pointing to it.
1388 * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
1389 * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
1390 * 9. We can't remove a root or mountpoint.
1391 * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
1392 * nfs_async_unlink().
1393 */
Arjan van de Ven858119e2006-01-14 13:20:43 -08001394static int may_delete(struct inode *dir,struct dentry *victim,int isdir)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395{
1396 int error;
1397
1398 if (!victim->d_inode)
1399 return -ENOENT;
1400
1401 BUG_ON(victim->d_parent->d_inode != dir);
Al Viro5a190ae2007-06-07 12:19:32 -04001402 audit_inode_child(victim->d_name.name, victim, dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001403
Al Virof419a2e2008-07-22 00:07:17 -04001404 error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 if (error)
1406 return error;
1407 if (IS_APPEND(dir))
1408 return -EPERM;
1409 if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)||
1410 IS_IMMUTABLE(victim->d_inode))
1411 return -EPERM;
1412 if (isdir) {
1413 if (!S_ISDIR(victim->d_inode->i_mode))
1414 return -ENOTDIR;
1415 if (IS_ROOT(victim))
1416 return -EBUSY;
1417 } else if (S_ISDIR(victim->d_inode->i_mode))
1418 return -EISDIR;
1419 if (IS_DEADDIR(dir))
1420 return -ENOENT;
1421 if (victim->d_flags & DCACHE_NFSFS_RENAMED)
1422 return -EBUSY;
1423 return 0;
1424}
1425
1426/* Check whether we can create an object with dentry child in directory
1427 * dir.
1428 * 1. We can't do it if child already exists (open has special treatment for
1429 * this case, but since we are inlined it's OK)
1430 * 2. We can't do it if dir is read-only (done in permission())
1431 * 3. We should have write and exec permissions on dir
1432 * 4. We can't do it if dir is immutable (done in permission())
1433 */
Miklos Szeredia95164d2008-07-30 15:08:48 +02001434static inline int may_create(struct inode *dir, struct dentry *child)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435{
1436 if (child->d_inode)
1437 return -EEXIST;
1438 if (IS_DEADDIR(dir))
1439 return -ENOENT;
Al Virof419a2e2008-07-22 00:07:17 -04001440 return inode_permission(dir, MAY_WRITE | MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441}
1442
1443/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001444 * O_DIRECTORY translates into forcing a directory lookup.
1445 */
1446static inline int lookup_flags(unsigned int f)
1447{
1448 unsigned long retval = LOOKUP_FOLLOW;
1449
1450 if (f & O_NOFOLLOW)
1451 retval &= ~LOOKUP_FOLLOW;
1452
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 if (f & O_DIRECTORY)
1454 retval |= LOOKUP_DIRECTORY;
1455
1456 return retval;
1457}
1458
1459/*
1460 * p1 and p2 should be directories on the same fs.
1461 */
1462struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)
1463{
1464 struct dentry *p;
1465
1466 if (p1 == p2) {
Ingo Molnarf2eace22006-07-03 00:25:05 -07001467 mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 return NULL;
1469 }
1470
Arjan van de Vena11f3a02006-03-23 03:00:33 -08001471 mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472
1473 for (p = p1; p->d_parent != p; p = p->d_parent) {
1474 if (p->d_parent == p2) {
Ingo Molnarf2eace22006-07-03 00:25:05 -07001475 mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT);
1476 mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477 return p;
1478 }
1479 }
1480
1481 for (p = p2; p->d_parent != p; p = p->d_parent) {
1482 if (p->d_parent == p1) {
Ingo Molnarf2eace22006-07-03 00:25:05 -07001483 mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
1484 mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 return p;
1486 }
1487 }
1488
Ingo Molnarf2eace22006-07-03 00:25:05 -07001489 mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
1490 mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 return NULL;
1492}
1493
1494void unlock_rename(struct dentry *p1, struct dentry *p2)
1495{
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001496 mutex_unlock(&p1->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001497 if (p1 != p2) {
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001498 mutex_unlock(&p2->d_inode->i_mutex);
Arjan van de Vena11f3a02006-03-23 03:00:33 -08001499 mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 }
1501}
1502
1503int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
1504 struct nameidata *nd)
1505{
Miklos Szeredia95164d2008-07-30 15:08:48 +02001506 int error = may_create(dir, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507
1508 if (error)
1509 return error;
1510
1511 if (!dir->i_op || !dir->i_op->create)
1512 return -EACCES; /* shouldn't it be ENOSYS? */
1513 mode &= S_IALLUGO;
1514 mode |= S_IFREG;
1515 error = security_inode_create(dir, dentry, mode);
1516 if (error)
1517 return error;
1518 DQUOT_INIT(dir);
1519 error = dir->i_op->create(dir, dentry, mode, nd);
Stephen Smalleya74574a2005-09-09 13:01:44 -07001520 if (!error)
Amy Griffisf38aa942005-11-03 15:57:06 +00001521 fsnotify_create(dir, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001522 return error;
1523}
1524
1525int may_open(struct nameidata *nd, int acc_mode, int flag)
1526{
Jan Blunck4ac91372008-02-14 19:34:32 -08001527 struct dentry *dentry = nd->path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001528 struct inode *inode = dentry->d_inode;
1529 int error;
1530
1531 if (!inode)
1532 return -ENOENT;
1533
1534 if (S_ISLNK(inode->i_mode))
1535 return -ELOOP;
1536
Linus Torvalds974a9f02008-01-12 14:06:34 -08001537 if (S_ISDIR(inode->i_mode) && (acc_mode & MAY_WRITE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538 return -EISDIR;
1539
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540 /*
1541 * FIFO's, sockets and device files are special: they don't
1542 * actually live on the filesystem itself, and as such you
1543 * can write to them even if the filesystem is read-only.
1544 */
1545 if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
1546 flag &= ~O_TRUNC;
1547 } else if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
Jan Blunck4ac91372008-02-14 19:34:32 -08001548 if (nd->path.mnt->mnt_flags & MNT_NODEV)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549 return -EACCES;
1550
1551 flag &= ~O_TRUNC;
Dave Hansen4a3fd212008-02-15 14:37:48 -08001552 }
Dave Hansenb41572e2007-10-16 23:31:14 -07001553
1554 error = vfs_permission(nd, acc_mode);
1555 if (error)
1556 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557 /*
1558 * An append-only file must be opened in append mode for writing.
1559 */
1560 if (IS_APPEND(inode)) {
1561 if ((flag & FMODE_WRITE) && !(flag & O_APPEND))
1562 return -EPERM;
1563 if (flag & O_TRUNC)
1564 return -EPERM;
1565 }
1566
1567 /* O_NOATIME can only be set by the owner or superuser */
1568 if (flag & O_NOATIME)
Satyam Sharma3bd858a2007-07-17 15:00:08 +05301569 if (!is_owner_or_cap(inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 return -EPERM;
1571
1572 /*
1573 * Ensure there are no outstanding leases on the file.
1574 */
1575 error = break_lease(inode, flag);
1576 if (error)
1577 return error;
1578
1579 if (flag & O_TRUNC) {
1580 error = get_write_access(inode);
1581 if (error)
1582 return error;
1583
1584 /*
1585 * Refuse to truncate files with mandatory locks held on them.
1586 */
1587 error = locks_verify_locked(inode);
1588 if (!error) {
1589 DQUOT_INIT(inode);
Miklos Szeredid139d7f2007-10-18 03:07:00 -07001590
1591 error = do_truncate(dentry, 0,
1592 ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
1593 NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594 }
1595 put_write_access(inode);
1596 if (error)
1597 return error;
1598 } else
1599 if (flag & FMODE_WRITE)
1600 DQUOT_INIT(inode);
1601
1602 return 0;
1603}
1604
Dave Hansend57999e2008-02-15 14:37:27 -08001605/*
1606 * Be careful about ever adding any more callers of this
1607 * function. Its flags must be in the namei format, not
1608 * what get passed to sys_open().
1609 */
1610static int __open_namei_create(struct nameidata *nd, struct path *path,
Dave Hansenaab520e2006-09-30 23:29:02 -07001611 int flag, int mode)
1612{
1613 int error;
Jan Blunck4ac91372008-02-14 19:34:32 -08001614 struct dentry *dir = nd->path.dentry;
Dave Hansenaab520e2006-09-30 23:29:02 -07001615
1616 if (!IS_POSIXACL(dir->d_inode))
1617 mode &= ~current->fs->umask;
1618 error = vfs_create(dir->d_inode, path->dentry, mode, nd);
1619 mutex_unlock(&dir->d_inode->i_mutex);
Jan Blunck4ac91372008-02-14 19:34:32 -08001620 dput(nd->path.dentry);
1621 nd->path.dentry = path->dentry;
Dave Hansenaab520e2006-09-30 23:29:02 -07001622 if (error)
1623 return error;
1624 /* Don't check for write permission, don't truncate */
1625 return may_open(nd, 0, flag & ~O_TRUNC);
1626}
1627
Linus Torvalds1da177e2005-04-16 15:20:36 -07001628/*
Dave Hansend57999e2008-02-15 14:37:27 -08001629 * Note that while the flag value (low two bits) for sys_open means:
1630 * 00 - read-only
1631 * 01 - write-only
1632 * 10 - read-write
1633 * 11 - special
1634 * it is changed into
1635 * 00 - no permissions needed
1636 * 01 - read-permission
1637 * 10 - write-permission
1638 * 11 - read-write
1639 * for the internal routines (ie open_namei()/follow_link() etc)
1640 * This is more logical, and also allows the 00 "no perm needed"
1641 * to be used for symlinks (where the permissions are checked
1642 * later).
1643 *
1644*/
1645static inline int open_to_namei_flags(int flag)
1646{
1647 if ((flag+1) & O_ACCMODE)
1648 flag++;
1649 return flag;
1650}
1651
Dave Hansen4a3fd212008-02-15 14:37:48 -08001652static int open_will_write_to_fs(int flag, struct inode *inode)
1653{
1654 /*
1655 * We'll never write to the fs underlying
1656 * a device file.
1657 */
1658 if (special_file(inode->i_mode))
1659 return 0;
1660 return (flag & O_TRUNC);
1661}
1662
Dave Hansend57999e2008-02-15 14:37:27 -08001663/*
Dave Hansen4a3fd212008-02-15 14:37:48 -08001664 * Note that the low bits of the passed in "open_flag"
1665 * are not the same as in the local variable "flag". See
1666 * open_to_namei_flags() for more details.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001667 */
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001668struct file *do_filp_open(int dfd, const char *pathname,
1669 int open_flag, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670{
Dave Hansen4a3fd212008-02-15 14:37:48 -08001671 struct file *filp;
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001672 struct nameidata nd;
Trond Myklebust834f2a42005-10-18 14:20:16 -07001673 int acc_mode, error;
Al Viro4e7506e2005-06-06 13:36:00 -07001674 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675 struct dentry *dir;
1676 int count = 0;
Dave Hansen4a3fd212008-02-15 14:37:48 -08001677 int will_write;
Dave Hansend57999e2008-02-15 14:37:27 -08001678 int flag = open_to_namei_flags(open_flag);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679
Al Virob77b0642008-07-17 09:37:02 -04001680 acc_mode = MAY_OPEN | ACC_MODE(flag);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681
Trond Myklebust834f2a42005-10-18 14:20:16 -07001682 /* O_TRUNC implies we need access checks for write permissions */
1683 if (flag & O_TRUNC)
1684 acc_mode |= MAY_WRITE;
1685
Linus Torvalds1da177e2005-04-16 15:20:36 -07001686 /* Allow the LSM permission hook to distinguish append
1687 access from general write access. */
1688 if (flag & O_APPEND)
1689 acc_mode |= MAY_APPEND;
1690
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 /*
1692 * The simplest case - just a plain lookup.
1693 */
1694 if (!(flag & O_CREAT)) {
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001695 error = path_lookup_open(dfd, pathname, lookup_flags(flag),
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001696 &nd, flag);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 if (error)
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001698 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699 goto ok;
1700 }
1701
1702 /*
1703 * Create - we need to know the parent.
1704 */
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001705 error = path_lookup_create(dfd, pathname, LOOKUP_PARENT,
1706 &nd, flag, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707 if (error)
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001708 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709
1710 /*
1711 * We have the parent and last component. First of all, check
1712 * that we are not asked to creat(2) an obvious directory - that
1713 * will not do.
1714 */
1715 error = -EISDIR;
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001716 if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len])
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717 goto exit;
1718
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001719 dir = nd.path.dentry;
1720 nd.flags &= ~LOOKUP_PARENT;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001721 mutex_lock(&dir->d_inode->i_mutex);
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001722 path.dentry = lookup_hash(&nd);
1723 path.mnt = nd.path.mnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724
1725do_last:
Al Viro4e7506e2005-06-06 13:36:00 -07001726 error = PTR_ERR(path.dentry);
1727 if (IS_ERR(path.dentry)) {
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001728 mutex_unlock(&dir->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001729 goto exit;
1730 }
1731
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001732 if (IS_ERR(nd.intent.open.file)) {
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001733 error = PTR_ERR(nd.intent.open.file);
Dave Hansen4a3fd212008-02-15 14:37:48 -08001734 goto exit_mutex_unlock;
Oleg Drokin4af4c522006-03-25 03:06:54 -08001735 }
1736
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 /* Negative dentry, just create the file */
Al Viro4e7506e2005-06-06 13:36:00 -07001738 if (!path.dentry->d_inode) {
Dave Hansen4a3fd212008-02-15 14:37:48 -08001739 /*
1740 * This write is needed to ensure that a
1741 * ro->rw transition does not occur between
1742 * the time when the file is created and when
1743 * a permanent write count is taken through
1744 * the 'struct file' in nameidata_to_filp().
1745 */
1746 error = mnt_want_write(nd.path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001747 if (error)
Dave Hansen4a3fd212008-02-15 14:37:48 -08001748 goto exit_mutex_unlock;
1749 error = __open_namei_create(&nd, &path, flag, mode);
1750 if (error) {
1751 mnt_drop_write(nd.path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752 goto exit;
Dave Hansen4a3fd212008-02-15 14:37:48 -08001753 }
1754 filp = nameidata_to_filp(&nd, open_flag);
1755 mnt_drop_write(nd.path.mnt);
1756 return filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757 }
1758
1759 /*
1760 * It already exists.
1761 */
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001762 mutex_unlock(&dir->d_inode->i_mutex);
Al Viro5a190ae2007-06-07 12:19:32 -04001763 audit_inode(pathname, path.dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001764
1765 error = -EEXIST;
1766 if (flag & O_EXCL)
1767 goto exit_dput;
1768
Al Viroe13b2102005-06-06 13:36:06 -07001769 if (__follow_mount(&path)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770 error = -ELOOP;
Al Viroba7a4c12005-06-06 13:36:08 -07001771 if (flag & O_NOFOLLOW)
1772 goto exit_dput;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 }
Amy Griffis3e2efce2006-07-13 13:16:02 -04001774
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775 error = -ENOENT;
Al Viro4e7506e2005-06-06 13:36:00 -07001776 if (!path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777 goto exit_dput;
Al Viro4e7506e2005-06-06 13:36:00 -07001778 if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779 goto do_link;
1780
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001781 path_to_nameidata(&path, &nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782 error = -EISDIR;
Al Viro4e7506e2005-06-06 13:36:00 -07001783 if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 goto exit;
1785ok:
Dave Hansen4a3fd212008-02-15 14:37:48 -08001786 /*
1787 * Consider:
1788 * 1. may_open() truncates a file
1789 * 2. a rw->ro mount transition occurs
1790 * 3. nameidata_to_filp() fails due to
1791 * the ro mount.
1792 * That would be inconsistent, and should
1793 * be avoided. Taking this mnt write here
1794 * ensures that (2) can not occur.
1795 */
1796 will_write = open_will_write_to_fs(flag, nd.path.dentry->d_inode);
1797 if (will_write) {
1798 error = mnt_want_write(nd.path.mnt);
1799 if (error)
1800 goto exit;
1801 }
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001802 error = may_open(&nd, acc_mode, flag);
Dave Hansen4a3fd212008-02-15 14:37:48 -08001803 if (error) {
1804 if (will_write)
1805 mnt_drop_write(nd.path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001806 goto exit;
Dave Hansen4a3fd212008-02-15 14:37:48 -08001807 }
1808 filp = nameidata_to_filp(&nd, open_flag);
1809 /*
1810 * It is now safe to drop the mnt write
1811 * because the filp has had a write taken
1812 * on its behalf.
1813 */
1814 if (will_write)
1815 mnt_drop_write(nd.path.mnt);
1816 return filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817
Dave Hansen4a3fd212008-02-15 14:37:48 -08001818exit_mutex_unlock:
1819 mutex_unlock(&dir->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820exit_dput:
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001821 path_put_conditional(&path, &nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822exit:
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001823 if (!IS_ERR(nd.intent.open.file))
1824 release_open_intent(&nd);
1825 path_put(&nd.path);
1826 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827
1828do_link:
1829 error = -ELOOP;
1830 if (flag & O_NOFOLLOW)
1831 goto exit_dput;
1832 /*
1833 * This is subtle. Instead of calling do_follow_link() we do the
1834 * thing by hands. The reason is that this way we have zero link_count
1835 * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT.
1836 * After that we have the parent and last component, i.e.
1837 * we are in the same situation as after the first path_walk().
1838 * Well, almost - if the last component is normal we get its copy
1839 * stored in nd->last.name and we will have to putname() it when we
1840 * are done. Procfs-like symlinks just set LAST_BIND.
1841 */
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001842 nd.flags |= LOOKUP_PARENT;
1843 error = security_inode_follow_link(path.dentry, &nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844 if (error)
1845 goto exit_dput;
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001846 error = __do_follow_link(&path, &nd);
Kirill Korotaevde459212006-07-14 00:23:49 -07001847 if (error) {
1848 /* Does someone understand code flow here? Or it is only
1849 * me so stupid? Anathema to whoever designed this non-sense
1850 * with "intent.open".
1851 */
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001852 release_open_intent(&nd);
1853 return ERR_PTR(error);
Kirill Korotaevde459212006-07-14 00:23:49 -07001854 }
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001855 nd.flags &= ~LOOKUP_PARENT;
1856 if (nd.last_type == LAST_BIND)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 goto ok;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858 error = -EISDIR;
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001859 if (nd.last_type != LAST_NORM)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001860 goto exit;
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001861 if (nd.last.name[nd.last.len]) {
1862 __putname(nd.last.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863 goto exit;
1864 }
1865 error = -ELOOP;
1866 if (count++==32) {
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001867 __putname(nd.last.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001868 goto exit;
1869 }
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001870 dir = nd.path.dentry;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001871 mutex_lock(&dir->d_inode->i_mutex);
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001872 path.dentry = lookup_hash(&nd);
1873 path.mnt = nd.path.mnt;
1874 __putname(nd.last.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 goto do_last;
1876}
1877
1878/**
Christoph Hellwiga70e65d2008-02-15 14:37:28 -08001879 * filp_open - open file and return file pointer
1880 *
1881 * @filename: path to open
1882 * @flags: open flags as per the open(2) second argument
1883 * @mode: mode for the new file if O_CREAT is set, else ignored
1884 *
1885 * This is the helper to open a file from kernelspace if you really
1886 * have to. But in generally you should not do this, so please move
1887 * along, nothing to see here..
1888 */
1889struct file *filp_open(const char *filename, int flags, int mode)
1890{
1891 return do_filp_open(AT_FDCWD, filename, flags, mode);
1892}
1893EXPORT_SYMBOL(filp_open);
1894
1895/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896 * lookup_create - lookup a dentry, creating it if it doesn't exist
1897 * @nd: nameidata info
1898 * @is_dir: directory flag
1899 *
1900 * Simple function to lookup and return a dentry and create it
1901 * if it doesn't exist. Is SMP-safe.
Christoph Hellwigc663e5d2005-06-23 00:09:49 -07001902 *
Jan Blunck4ac91372008-02-14 19:34:32 -08001903 * Returns with nd->path.dentry->d_inode->i_mutex locked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904 */
1905struct dentry *lookup_create(struct nameidata *nd, int is_dir)
1906{
Christoph Hellwigc663e5d2005-06-23 00:09:49 -07001907 struct dentry *dentry = ERR_PTR(-EEXIST);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908
Jan Blunck4ac91372008-02-14 19:34:32 -08001909 mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
Christoph Hellwigc663e5d2005-06-23 00:09:49 -07001910 /*
1911 * Yucky last component or no last component at all?
1912 * (foo/., foo/.., /////)
1913 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914 if (nd->last_type != LAST_NORM)
1915 goto fail;
1916 nd->flags &= ~LOOKUP_PARENT;
ASANO Masahiroa6349042006-08-22 20:06:02 -04001917 nd->flags |= LOOKUP_CREATE;
1918 nd->intent.open.flags = O_EXCL;
Christoph Hellwigc663e5d2005-06-23 00:09:49 -07001919
1920 /*
1921 * Do the final lookup.
1922 */
Christoph Hellwig49705b72005-11-08 21:35:06 -08001923 dentry = lookup_hash(nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 if (IS_ERR(dentry))
1925 goto fail;
Christoph Hellwigc663e5d2005-06-23 00:09:49 -07001926
Al Viroe9baf6e2008-05-15 04:49:12 -04001927 if (dentry->d_inode)
1928 goto eexist;
Christoph Hellwigc663e5d2005-06-23 00:09:49 -07001929 /*
1930 * Special case - lookup gave negative, but... we had foo/bar/
1931 * From the vfs_mknod() POV we just have a negative dentry -
1932 * all is fine. Let's be bastards - you had / on the end, you've
1933 * been asking for (non-existent) directory. -ENOENT for you.
1934 */
Al Viroe9baf6e2008-05-15 04:49:12 -04001935 if (unlikely(!is_dir && nd->last.name[nd->last.len])) {
1936 dput(dentry);
1937 dentry = ERR_PTR(-ENOENT);
1938 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939 return dentry;
Al Viroe9baf6e2008-05-15 04:49:12 -04001940eexist:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941 dput(dentry);
Al Viroe9baf6e2008-05-15 04:49:12 -04001942 dentry = ERR_PTR(-EEXIST);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943fail:
1944 return dentry;
1945}
Christoph Hellwigf81a0bf2005-05-19 12:26:43 -07001946EXPORT_SYMBOL_GPL(lookup_create);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001947
1948int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
1949{
Miklos Szeredia95164d2008-07-30 15:08:48 +02001950 int error = may_create(dir, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951
1952 if (error)
1953 return error;
1954
1955 if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD))
1956 return -EPERM;
1957
1958 if (!dir->i_op || !dir->i_op->mknod)
1959 return -EPERM;
1960
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -07001961 error = devcgroup_inode_mknod(mode, dev);
1962 if (error)
1963 return error;
1964
Linus Torvalds1da177e2005-04-16 15:20:36 -07001965 error = security_inode_mknod(dir, dentry, mode, dev);
1966 if (error)
1967 return error;
1968
1969 DQUOT_INIT(dir);
1970 error = dir->i_op->mknod(dir, dentry, mode, dev);
Stephen Smalleya74574a2005-09-09 13:01:44 -07001971 if (!error)
Amy Griffisf38aa942005-11-03 15:57:06 +00001972 fsnotify_create(dir, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973 return error;
1974}
1975
Dave Hansen463c3192008-02-15 14:37:57 -08001976static int may_mknod(mode_t mode)
1977{
1978 switch (mode & S_IFMT) {
1979 case S_IFREG:
1980 case S_IFCHR:
1981 case S_IFBLK:
1982 case S_IFIFO:
1983 case S_IFSOCK:
1984 case 0: /* zero mode translates to S_IFREG */
1985 return 0;
1986 case S_IFDIR:
1987 return -EPERM;
1988 default:
1989 return -EINVAL;
1990 }
1991}
1992
Ulrich Drepper5590ff02006-01-18 17:43:53 -08001993asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
1994 unsigned dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001995{
Al Viro2ad94ae2008-07-21 09:32:51 -04001996 int error;
1997 char *tmp;
1998 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001999 struct nameidata nd;
2000
2001 if (S_ISDIR(mode))
2002 return -EPERM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003
Al Viro2ad94ae2008-07-21 09:32:51 -04002004 error = user_path_parent(dfd, filename, &nd, &tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002005 if (error)
Al Viro2ad94ae2008-07-21 09:32:51 -04002006 return error;
2007
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 dentry = lookup_create(&nd, 0);
Dave Hansen463c3192008-02-15 14:37:57 -08002009 if (IS_ERR(dentry)) {
2010 error = PTR_ERR(dentry);
2011 goto out_unlock;
2012 }
Jan Blunck4ac91372008-02-14 19:34:32 -08002013 if (!IS_POSIXACL(nd.path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002014 mode &= ~current->fs->umask;
Dave Hansen463c3192008-02-15 14:37:57 -08002015 error = may_mknod(mode);
2016 if (error)
2017 goto out_dput;
2018 error = mnt_want_write(nd.path.mnt);
2019 if (error)
2020 goto out_dput;
2021 switch (mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002022 case 0: case S_IFREG:
Jan Blunck4ac91372008-02-14 19:34:32 -08002023 error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002024 break;
2025 case S_IFCHR: case S_IFBLK:
Jan Blunck4ac91372008-02-14 19:34:32 -08002026 error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002027 new_decode_dev(dev));
2028 break;
2029 case S_IFIFO: case S_IFSOCK:
Jan Blunck4ac91372008-02-14 19:34:32 -08002030 error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002031 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002032 }
Dave Hansen463c3192008-02-15 14:37:57 -08002033 mnt_drop_write(nd.path.mnt);
2034out_dput:
2035 dput(dentry);
2036out_unlock:
Jan Blunck4ac91372008-02-14 19:34:32 -08002037 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
Jan Blunck1d957f92008-02-14 19:34:35 -08002038 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002039 putname(tmp);
2040
2041 return error;
2042}
2043
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002044asmlinkage long sys_mknod(const char __user *filename, int mode, unsigned dev)
2045{
2046 return sys_mknodat(AT_FDCWD, filename, mode, dev);
2047}
2048
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
2050{
Miklos Szeredia95164d2008-07-30 15:08:48 +02002051 int error = may_create(dir, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052
2053 if (error)
2054 return error;
2055
2056 if (!dir->i_op || !dir->i_op->mkdir)
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
2064 DQUOT_INIT(dir);
2065 error = dir->i_op->mkdir(dir, dentry, mode);
Stephen Smalleya74574a2005-09-09 13:01:44 -07002066 if (!error)
Amy Griffisf38aa942005-11-03 15:57:06 +00002067 fsnotify_mkdir(dir, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002068 return error;
2069}
2070
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002071asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002072{
2073 int error = 0;
2074 char * tmp;
Dave Hansen6902d922006-09-30 23:29:01 -07002075 struct dentry *dentry;
2076 struct nameidata nd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002077
Al Viro2ad94ae2008-07-21 09:32:51 -04002078 error = user_path_parent(dfd, pathname, &nd, &tmp);
2079 if (error)
Dave Hansen6902d922006-09-30 23:29:01 -07002080 goto out_err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002081
Dave Hansen6902d922006-09-30 23:29:01 -07002082 dentry = lookup_create(&nd, 1);
2083 error = PTR_ERR(dentry);
2084 if (IS_ERR(dentry))
2085 goto out_unlock;
2086
Jan Blunck4ac91372008-02-14 19:34:32 -08002087 if (!IS_POSIXACL(nd.path.dentry->d_inode))
Dave Hansen6902d922006-09-30 23:29:01 -07002088 mode &= ~current->fs->umask;
Dave Hansen463c3192008-02-15 14:37:57 -08002089 error = mnt_want_write(nd.path.mnt);
2090 if (error)
2091 goto out_dput;
Jan Blunck4ac91372008-02-14 19:34:32 -08002092 error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
Dave Hansen463c3192008-02-15 14:37:57 -08002093 mnt_drop_write(nd.path.mnt);
2094out_dput:
Dave Hansen6902d922006-09-30 23:29:01 -07002095 dput(dentry);
2096out_unlock:
Jan Blunck4ac91372008-02-14 19:34:32 -08002097 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
Jan Blunck1d957f92008-02-14 19:34:35 -08002098 path_put(&nd.path);
Dave Hansen6902d922006-09-30 23:29:01 -07002099 putname(tmp);
2100out_err:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002101 return error;
2102}
2103
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002104asmlinkage long sys_mkdir(const char __user *pathname, int mode)
2105{
2106 return sys_mkdirat(AT_FDCWD, pathname, mode);
2107}
2108
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109/*
2110 * We try to drop the dentry early: we should have
2111 * a usage count of 2 if we're the only user of this
2112 * dentry, and if that is true (possibly after pruning
2113 * the dcache), then we drop the dentry now.
2114 *
2115 * A low-level filesystem can, if it choses, legally
2116 * do a
2117 *
2118 * if (!d_unhashed(dentry))
2119 * return -EBUSY;
2120 *
2121 * if it cannot handle the case of removing a directory
2122 * that is still in use by something else..
2123 */
2124void dentry_unhash(struct dentry *dentry)
2125{
2126 dget(dentry);
Vasily Averindc168422006-12-06 20:37:07 -08002127 shrink_dcache_parent(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002128 spin_lock(&dcache_lock);
2129 spin_lock(&dentry->d_lock);
2130 if (atomic_read(&dentry->d_count) == 2)
2131 __d_drop(dentry);
2132 spin_unlock(&dentry->d_lock);
2133 spin_unlock(&dcache_lock);
2134}
2135
2136int vfs_rmdir(struct inode *dir, struct dentry *dentry)
2137{
2138 int error = may_delete(dir, dentry, 1);
2139
2140 if (error)
2141 return error;
2142
2143 if (!dir->i_op || !dir->i_op->rmdir)
2144 return -EPERM;
2145
2146 DQUOT_INIT(dir);
2147
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002148 mutex_lock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002149 dentry_unhash(dentry);
2150 if (d_mountpoint(dentry))
2151 error = -EBUSY;
2152 else {
2153 error = security_inode_rmdir(dir, dentry);
2154 if (!error) {
2155 error = dir->i_op->rmdir(dir, dentry);
2156 if (!error)
2157 dentry->d_inode->i_flags |= S_DEAD;
2158 }
2159 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002160 mutex_unlock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002161 if (!error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002162 d_delete(dentry);
2163 }
2164 dput(dentry);
2165
2166 return error;
2167}
2168
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002169static long do_rmdir(int dfd, const char __user *pathname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002170{
2171 int error = 0;
2172 char * name;
2173 struct dentry *dentry;
2174 struct nameidata nd;
2175
Al Viro2ad94ae2008-07-21 09:32:51 -04002176 error = user_path_parent(dfd, pathname, &nd, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002177 if (error)
Al Viro2ad94ae2008-07-21 09:32:51 -04002178 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179
2180 switch(nd.last_type) {
2181 case LAST_DOTDOT:
2182 error = -ENOTEMPTY;
2183 goto exit1;
2184 case LAST_DOT:
2185 error = -EINVAL;
2186 goto exit1;
2187 case LAST_ROOT:
2188 error = -EBUSY;
2189 goto exit1;
2190 }
Jan Blunck4ac91372008-02-14 19:34:32 -08002191 mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
Christoph Hellwig49705b72005-11-08 21:35:06 -08002192 dentry = lookup_hash(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002193 error = PTR_ERR(dentry);
Dave Hansen6902d922006-09-30 23:29:01 -07002194 if (IS_ERR(dentry))
2195 goto exit2;
Dave Hansen06227532008-02-15 14:37:34 -08002196 error = mnt_want_write(nd.path.mnt);
2197 if (error)
2198 goto exit3;
Jan Blunck4ac91372008-02-14 19:34:32 -08002199 error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
Dave Hansen06227532008-02-15 14:37:34 -08002200 mnt_drop_write(nd.path.mnt);
2201exit3:
Dave Hansen6902d922006-09-30 23:29:01 -07002202 dput(dentry);
2203exit2:
Jan Blunck4ac91372008-02-14 19:34:32 -08002204 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002205exit1:
Jan Blunck1d957f92008-02-14 19:34:35 -08002206 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207 putname(name);
2208 return error;
2209}
2210
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002211asmlinkage long sys_rmdir(const char __user *pathname)
2212{
2213 return do_rmdir(AT_FDCWD, pathname);
2214}
2215
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216int vfs_unlink(struct inode *dir, struct dentry *dentry)
2217{
2218 int error = may_delete(dir, dentry, 0);
2219
2220 if (error)
2221 return error;
2222
2223 if (!dir->i_op || !dir->i_op->unlink)
2224 return -EPERM;
2225
2226 DQUOT_INIT(dir);
2227
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002228 mutex_lock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002229 if (d_mountpoint(dentry))
2230 error = -EBUSY;
2231 else {
2232 error = security_inode_unlink(dir, dentry);
2233 if (!error)
2234 error = dir->i_op->unlink(dir, dentry);
2235 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002236 mutex_unlock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002237
2238 /* We don't d_delete() NFS sillyrenamed files--they still exist. */
2239 if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
Jan Karaece95912008-02-06 01:37:13 -08002240 fsnotify_link_count(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002241 d_delete(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002242 }
Robert Love0eeca282005-07-12 17:06:03 -04002243
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244 return error;
2245}
2246
2247/*
2248 * Make sure that the actual truncation of the file will occur outside its
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002249 * directory's i_mutex. Truncate can take a long time if there is a lot of
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250 * writeout happening, and we don't want to prevent access to the directory
2251 * while waiting on the I/O.
2252 */
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002253static long do_unlinkat(int dfd, const char __user *pathname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002254{
Al Viro2ad94ae2008-07-21 09:32:51 -04002255 int error;
2256 char *name;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002257 struct dentry *dentry;
2258 struct nameidata nd;
2259 struct inode *inode = NULL;
2260
Al Viro2ad94ae2008-07-21 09:32:51 -04002261 error = user_path_parent(dfd, pathname, &nd, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262 if (error)
Al Viro2ad94ae2008-07-21 09:32:51 -04002263 return error;
2264
Linus Torvalds1da177e2005-04-16 15:20:36 -07002265 error = -EISDIR;
2266 if (nd.last_type != LAST_NORM)
2267 goto exit1;
Jan Blunck4ac91372008-02-14 19:34:32 -08002268 mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
Christoph Hellwig49705b72005-11-08 21:35:06 -08002269 dentry = lookup_hash(&nd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270 error = PTR_ERR(dentry);
2271 if (!IS_ERR(dentry)) {
2272 /* Why not before? Because we want correct error value */
2273 if (nd.last.name[nd.last.len])
2274 goto slashes;
2275 inode = dentry->d_inode;
2276 if (inode)
2277 atomic_inc(&inode->i_count);
Dave Hansen06227532008-02-15 14:37:34 -08002278 error = mnt_want_write(nd.path.mnt);
2279 if (error)
2280 goto exit2;
Jan Blunck4ac91372008-02-14 19:34:32 -08002281 error = vfs_unlink(nd.path.dentry->d_inode, dentry);
Dave Hansen06227532008-02-15 14:37:34 -08002282 mnt_drop_write(nd.path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002283 exit2:
2284 dput(dentry);
2285 }
Jan Blunck4ac91372008-02-14 19:34:32 -08002286 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002287 if (inode)
2288 iput(inode); /* truncate the inode here */
2289exit1:
Jan Blunck1d957f92008-02-14 19:34:35 -08002290 path_put(&nd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002291 putname(name);
2292 return error;
2293
2294slashes:
2295 error = !dentry->d_inode ? -ENOENT :
2296 S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR;
2297 goto exit2;
2298}
2299
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002300asmlinkage long sys_unlinkat(int dfd, const char __user *pathname, int flag)
2301{
2302 if ((flag & ~AT_REMOVEDIR) != 0)
2303 return -EINVAL;
2304
2305 if (flag & AT_REMOVEDIR)
2306 return do_rmdir(dfd, pathname);
2307
2308 return do_unlinkat(dfd, pathname);
2309}
2310
2311asmlinkage long sys_unlink(const char __user *pathname)
2312{
2313 return do_unlinkat(AT_FDCWD, pathname);
2314}
2315
Miklos Szeredidb2e7472008-06-24 16:50:16 +02002316int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002317{
Miklos Szeredia95164d2008-07-30 15:08:48 +02002318 int error = may_create(dir, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002319
2320 if (error)
2321 return error;
2322
2323 if (!dir->i_op || !dir->i_op->symlink)
2324 return -EPERM;
2325
2326 error = security_inode_symlink(dir, dentry, oldname);
2327 if (error)
2328 return error;
2329
2330 DQUOT_INIT(dir);
2331 error = dir->i_op->symlink(dir, dentry, oldname);
Stephen Smalleya74574a2005-09-09 13:01:44 -07002332 if (!error)
Amy Griffisf38aa942005-11-03 15:57:06 +00002333 fsnotify_create(dir, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002334 return error;
2335}
2336
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002337asmlinkage long sys_symlinkat(const char __user *oldname,
2338 int newdfd, const char __user *newname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002339{
Al Viro2ad94ae2008-07-21 09:32:51 -04002340 int error;
2341 char *from;
2342 char *to;
Dave Hansen6902d922006-09-30 23:29:01 -07002343 struct dentry *dentry;
2344 struct nameidata nd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002345
2346 from = getname(oldname);
Al Viro2ad94ae2008-07-21 09:32:51 -04002347 if (IS_ERR(from))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002348 return PTR_ERR(from);
Al Viro2ad94ae2008-07-21 09:32:51 -04002349
2350 error = user_path_parent(newdfd, newname, &nd, &to);
2351 if (error)
Dave Hansen6902d922006-09-30 23:29:01 -07002352 goto out_putname;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002353
Dave Hansen6902d922006-09-30 23:29:01 -07002354 dentry = lookup_create(&nd, 0);
2355 error = PTR_ERR(dentry);
2356 if (IS_ERR(dentry))
2357 goto out_unlock;
2358
Dave Hansen75c3f292008-02-15 14:37:45 -08002359 error = mnt_want_write(nd.path.mnt);
2360 if (error)
2361 goto out_dput;
Miklos Szeredidb2e7472008-06-24 16:50:16 +02002362 error = vfs_symlink(nd.path.dentry->d_inode, dentry, from);
Dave Hansen75c3f292008-02-15 14:37:45 -08002363 mnt_drop_write(nd.path.mnt);
2364out_dput:
Dave Hansen6902d922006-09-30 23:29:01 -07002365 dput(dentry);
2366out_unlock:
Jan Blunck4ac91372008-02-14 19:34:32 -08002367 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
Jan Blunck1d957f92008-02-14 19:34:35 -08002368 path_put(&nd.path);
Dave Hansen6902d922006-09-30 23:29:01 -07002369 putname(to);
2370out_putname:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002371 putname(from);
2372 return error;
2373}
2374
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002375asmlinkage long sys_symlink(const char __user *oldname, const char __user *newname)
2376{
2377 return sys_symlinkat(oldname, AT_FDCWD, newname);
2378}
2379
Linus Torvalds1da177e2005-04-16 15:20:36 -07002380int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
2381{
2382 struct inode *inode = old_dentry->d_inode;
2383 int error;
2384
2385 if (!inode)
2386 return -ENOENT;
2387
Miklos Szeredia95164d2008-07-30 15:08:48 +02002388 error = may_create(dir, new_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002389 if (error)
2390 return error;
2391
2392 if (dir->i_sb != inode->i_sb)
2393 return -EXDEV;
2394
2395 /*
2396 * A link to an append-only or immutable file cannot be created.
2397 */
2398 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
2399 return -EPERM;
2400 if (!dir->i_op || !dir->i_op->link)
2401 return -EPERM;
Tetsuo Handa7e79eed2008-06-24 16:50:15 +02002402 if (S_ISDIR(inode->i_mode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002403 return -EPERM;
2404
2405 error = security_inode_link(old_dentry, dir, new_dentry);
2406 if (error)
2407 return error;
2408
Tetsuo Handa7e79eed2008-06-24 16:50:15 +02002409 mutex_lock(&inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002410 DQUOT_INIT(dir);
2411 error = dir->i_op->link(old_dentry, dir, new_dentry);
Tetsuo Handa7e79eed2008-06-24 16:50:15 +02002412 mutex_unlock(&inode->i_mutex);
Stephen Smalleye31e14e2005-09-09 13:01:45 -07002413 if (!error)
Tetsuo Handa7e79eed2008-06-24 16:50:15 +02002414 fsnotify_link(dir, inode, new_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002415 return error;
2416}
2417
2418/*
2419 * Hardlinks are often used in delicate situations. We avoid
2420 * security-related surprises by not following symlinks on the
2421 * newname. --KAB
2422 *
2423 * We don't follow them on the oldname either to be compatible
2424 * with linux 2.0, and to avoid hard-linking to directories
2425 * and other special files. --ADM
2426 */
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002427asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
Ulrich Drepperc04030e2006-02-24 13:04:21 -08002428 int newdfd, const char __user *newname,
2429 int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002430{
2431 struct dentry *new_dentry;
Al Viro2d8f3032008-07-22 09:59:21 -04002432 struct nameidata nd;
2433 struct path old_path;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002434 int error;
Al Viro2ad94ae2008-07-21 09:32:51 -04002435 char *to;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002436
Ulrich Drepper45c9b112006-06-25 05:49:11 -07002437 if ((flags & ~AT_SYMLINK_FOLLOW) != 0)
Ulrich Drepperc04030e2006-02-24 13:04:21 -08002438 return -EINVAL;
2439
Al Viro2d8f3032008-07-22 09:59:21 -04002440 error = user_path_at(olddfd, oldname,
2441 flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
2442 &old_path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002443 if (error)
Al Viro2ad94ae2008-07-21 09:32:51 -04002444 return error;
2445
2446 error = user_path_parent(newdfd, newname, &nd, &to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002447 if (error)
2448 goto out;
2449 error = -EXDEV;
Al Viro2d8f3032008-07-22 09:59:21 -04002450 if (old_path.mnt != nd.path.mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451 goto out_release;
2452 new_dentry = lookup_create(&nd, 0);
2453 error = PTR_ERR(new_dentry);
Dave Hansen6902d922006-09-30 23:29:01 -07002454 if (IS_ERR(new_dentry))
2455 goto out_unlock;
Dave Hansen75c3f292008-02-15 14:37:45 -08002456 error = mnt_want_write(nd.path.mnt);
2457 if (error)
2458 goto out_dput;
Al Viro2d8f3032008-07-22 09:59:21 -04002459 error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry);
Dave Hansen75c3f292008-02-15 14:37:45 -08002460 mnt_drop_write(nd.path.mnt);
2461out_dput:
Dave Hansen6902d922006-09-30 23:29:01 -07002462 dput(new_dentry);
2463out_unlock:
Jan Blunck4ac91372008-02-14 19:34:32 -08002464 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002465out_release:
Jan Blunck1d957f92008-02-14 19:34:35 -08002466 path_put(&nd.path);
Al Viro2ad94ae2008-07-21 09:32:51 -04002467 putname(to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002468out:
Al Viro2d8f3032008-07-22 09:59:21 -04002469 path_put(&old_path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002470
2471 return error;
2472}
2473
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002474asmlinkage long sys_link(const char __user *oldname, const char __user *newname)
2475{
Ulrich Drepperc04030e2006-02-24 13:04:21 -08002476 return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002477}
2478
Linus Torvalds1da177e2005-04-16 15:20:36 -07002479/*
2480 * The worst of all namespace operations - renaming directory. "Perverted"
2481 * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
2482 * Problems:
2483 * a) we can get into loop creation. Check is done in is_subdir().
2484 * b) race potential - two innocent renames can create a loop together.
2485 * That's where 4.4 screws up. Current fix: serialization on
Arjan van de Vena11f3a02006-03-23 03:00:33 -08002486 * sb->s_vfs_rename_mutex. We might be more accurate, but that's another
Linus Torvalds1da177e2005-04-16 15:20:36 -07002487 * story.
2488 * c) we have to lock _three_ objects - parents and victim (if it exists).
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002489 * And that - after we got ->i_mutex on parents (until then we don't know
Linus Torvalds1da177e2005-04-16 15:20:36 -07002490 * whether the target exists). Solution: try to be smart with locking
2491 * order for inodes. We rely on the fact that tree topology may change
Arjan van de Vena11f3a02006-03-23 03:00:33 -08002492 * only under ->s_vfs_rename_mutex _and_ that parent of the object we
Linus Torvalds1da177e2005-04-16 15:20:36 -07002493 * move will be locked. Thus we can rank directories by the tree
2494 * (ancestors first) and rank all non-directories after them.
2495 * That works since everybody except rename does "lock parent, lookup,
Arjan van de Vena11f3a02006-03-23 03:00:33 -08002496 * lock child" and rename is under ->s_vfs_rename_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002497 * HOWEVER, it relies on the assumption that any object with ->lookup()
2498 * has no more than 1 dentry. If "hybrid" objects will ever appear,
2499 * we'd better make sure that there's no link(2) for them.
2500 * d) some filesystems don't support opened-but-unlinked directories,
2501 * either because of layout or because they are not ready to deal with
2502 * all cases correctly. The latter will be fixed (taking this sort of
2503 * stuff into VFS), but the former is not going away. Solution: the same
2504 * trick as in rmdir().
2505 * e) conversion from fhandle to dentry may come in the wrong moment - when
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002506 * we are removing the target. Solution: we will have to grab ->i_mutex
Linus Torvalds1da177e2005-04-16 15:20:36 -07002507 * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002508 * ->i_mutex on parents, which works but leads to some truely excessive
Linus Torvalds1da177e2005-04-16 15:20:36 -07002509 * locking].
2510 */
Adrian Bunk75c96f82005-05-05 16:16:09 -07002511static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
2512 struct inode *new_dir, struct dentry *new_dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513{
2514 int error = 0;
2515 struct inode *target;
2516
2517 /*
2518 * If we are going to change the parent - check write permissions,
2519 * we'll need to flip '..'.
2520 */
2521 if (new_dir != old_dir) {
Al Virof419a2e2008-07-22 00:07:17 -04002522 error = inode_permission(old_dentry->d_inode, MAY_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002523 if (error)
2524 return error;
2525 }
2526
2527 error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry);
2528 if (error)
2529 return error;
2530
2531 target = new_dentry->d_inode;
2532 if (target) {
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002533 mutex_lock(&target->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002534 dentry_unhash(new_dentry);
2535 }
2536 if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
2537 error = -EBUSY;
2538 else
2539 error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
2540 if (target) {
2541 if (!error)
2542 target->i_flags |= S_DEAD;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002543 mutex_unlock(&target->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002544 if (d_unhashed(new_dentry))
2545 d_rehash(new_dentry);
2546 dput(new_dentry);
2547 }
Stephen Smalleye31e14e2005-09-09 13:01:45 -07002548 if (!error)
Mark Fasheh349457c2006-09-08 14:22:21 -07002549 if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
2550 d_move(old_dentry,new_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002551 return error;
2552}
2553
Adrian Bunk75c96f82005-05-05 16:16:09 -07002554static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
2555 struct inode *new_dir, struct dentry *new_dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002556{
2557 struct inode *target;
2558 int error;
2559
2560 error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry);
2561 if (error)
2562 return error;
2563
2564 dget(new_dentry);
2565 target = new_dentry->d_inode;
2566 if (target)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002567 mutex_lock(&target->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002568 if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
2569 error = -EBUSY;
2570 else
2571 error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
2572 if (!error) {
Mark Fasheh349457c2006-09-08 14:22:21 -07002573 if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002574 d_move(old_dentry, new_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002575 }
2576 if (target)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002577 mutex_unlock(&target->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002578 dput(new_dentry);
2579 return error;
2580}
2581
2582int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
2583 struct inode *new_dir, struct dentry *new_dentry)
2584{
2585 int error;
2586 int is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
Robert Love0eeca282005-07-12 17:06:03 -04002587 const char *old_name;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002588
2589 if (old_dentry->d_inode == new_dentry->d_inode)
2590 return 0;
2591
2592 error = may_delete(old_dir, old_dentry, is_dir);
2593 if (error)
2594 return error;
2595
2596 if (!new_dentry->d_inode)
Miklos Szeredia95164d2008-07-30 15:08:48 +02002597 error = may_create(new_dir, new_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002598 else
2599 error = may_delete(new_dir, new_dentry, is_dir);
2600 if (error)
2601 return error;
2602
2603 if (!old_dir->i_op || !old_dir->i_op->rename)
2604 return -EPERM;
2605
2606 DQUOT_INIT(old_dir);
2607 DQUOT_INIT(new_dir);
2608
Robert Love0eeca282005-07-12 17:06:03 -04002609 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
2610
Linus Torvalds1da177e2005-04-16 15:20:36 -07002611 if (is_dir)
2612 error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry);
2613 else
2614 error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry);
2615 if (!error) {
Robert Love0eeca282005-07-12 17:06:03 -04002616 const char *new_name = old_dentry->d_name.name;
John McCutchan89204c42005-08-15 12:13:28 -04002617 fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir,
Al Viro5a190ae2007-06-07 12:19:32 -04002618 new_dentry->d_inode, old_dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002619 }
Robert Love0eeca282005-07-12 17:06:03 -04002620 fsnotify_oldname_free(old_name);
2621
Linus Torvalds1da177e2005-04-16 15:20:36 -07002622 return error;
2623}
2624
Al Viro2ad94ae2008-07-21 09:32:51 -04002625asmlinkage long sys_renameat(int olddfd, const char __user *oldname,
2626 int newdfd, const char __user *newname)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002627{
Al Viro2ad94ae2008-07-21 09:32:51 -04002628 struct dentry *old_dir, *new_dir;
2629 struct dentry *old_dentry, *new_dentry;
2630 struct dentry *trap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631 struct nameidata oldnd, newnd;
Al Viro2ad94ae2008-07-21 09:32:51 -04002632 char *from;
2633 char *to;
2634 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002635
Al Viro2ad94ae2008-07-21 09:32:51 -04002636 error = user_path_parent(olddfd, oldname, &oldnd, &from);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002637 if (error)
2638 goto exit;
2639
Al Viro2ad94ae2008-07-21 09:32:51 -04002640 error = user_path_parent(newdfd, newname, &newnd, &to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002641 if (error)
2642 goto exit1;
2643
2644 error = -EXDEV;
Jan Blunck4ac91372008-02-14 19:34:32 -08002645 if (oldnd.path.mnt != newnd.path.mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002646 goto exit2;
2647
Jan Blunck4ac91372008-02-14 19:34:32 -08002648 old_dir = oldnd.path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002649 error = -EBUSY;
2650 if (oldnd.last_type != LAST_NORM)
2651 goto exit2;
2652
Jan Blunck4ac91372008-02-14 19:34:32 -08002653 new_dir = newnd.path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002654 if (newnd.last_type != LAST_NORM)
2655 goto exit2;
2656
2657 trap = lock_rename(new_dir, old_dir);
2658
Christoph Hellwig49705b72005-11-08 21:35:06 -08002659 old_dentry = lookup_hash(&oldnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002660 error = PTR_ERR(old_dentry);
2661 if (IS_ERR(old_dentry))
2662 goto exit3;
2663 /* source must exist */
2664 error = -ENOENT;
2665 if (!old_dentry->d_inode)
2666 goto exit4;
2667 /* unless the source is a directory trailing slashes give -ENOTDIR */
2668 if (!S_ISDIR(old_dentry->d_inode->i_mode)) {
2669 error = -ENOTDIR;
2670 if (oldnd.last.name[oldnd.last.len])
2671 goto exit4;
2672 if (newnd.last.name[newnd.last.len])
2673 goto exit4;
2674 }
2675 /* source should not be ancestor of target */
2676 error = -EINVAL;
2677 if (old_dentry == trap)
2678 goto exit4;
Christoph Hellwig49705b72005-11-08 21:35:06 -08002679 new_dentry = lookup_hash(&newnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002680 error = PTR_ERR(new_dentry);
2681 if (IS_ERR(new_dentry))
2682 goto exit4;
2683 /* target should not be an ancestor of source */
2684 error = -ENOTEMPTY;
2685 if (new_dentry == trap)
2686 goto exit5;
2687
Dave Hansen9079b1e2008-02-15 14:37:49 -08002688 error = mnt_want_write(oldnd.path.mnt);
2689 if (error)
2690 goto exit5;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002691 error = vfs_rename(old_dir->d_inode, old_dentry,
2692 new_dir->d_inode, new_dentry);
Dave Hansen9079b1e2008-02-15 14:37:49 -08002693 mnt_drop_write(oldnd.path.mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002694exit5:
2695 dput(new_dentry);
2696exit4:
2697 dput(old_dentry);
2698exit3:
2699 unlock_rename(new_dir, old_dir);
2700exit2:
Jan Blunck1d957f92008-02-14 19:34:35 -08002701 path_put(&newnd.path);
Al Viro2ad94ae2008-07-21 09:32:51 -04002702 putname(to);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002703exit1:
Jan Blunck1d957f92008-02-14 19:34:35 -08002704 path_put(&oldnd.path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002705 putname(from);
Al Viro2ad94ae2008-07-21 09:32:51 -04002706exit:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002707 return error;
2708}
2709
Ulrich Drepper5590ff02006-01-18 17:43:53 -08002710asmlinkage long sys_rename(const char __user *oldname, const char __user *newname)
2711{
2712 return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname);
2713}
2714
Linus Torvalds1da177e2005-04-16 15:20:36 -07002715int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link)
2716{
2717 int len;
2718
2719 len = PTR_ERR(link);
2720 if (IS_ERR(link))
2721 goto out;
2722
2723 len = strlen(link);
2724 if (len > (unsigned) buflen)
2725 len = buflen;
2726 if (copy_to_user(buffer, link, len))
2727 len = -EFAULT;
2728out:
2729 return len;
2730}
2731
2732/*
2733 * A helper for ->readlink(). This should be used *ONLY* for symlinks that
2734 * have ->follow_link() touching nd only in nd_set_link(). Using (or not
2735 * using) it for any given inode is up to filesystem.
2736 */
2737int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
2738{
2739 struct nameidata nd;
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002740 void *cookie;
Marcin Slusarz694a1762008-06-09 16:40:37 -07002741 int res;
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002742
Linus Torvalds1da177e2005-04-16 15:20:36 -07002743 nd.depth = 0;
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002744 cookie = dentry->d_inode->i_op->follow_link(dentry, &nd);
Marcin Slusarz694a1762008-06-09 16:40:37 -07002745 if (IS_ERR(cookie))
2746 return PTR_ERR(cookie);
2747
2748 res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));
2749 if (dentry->d_inode->i_op->put_link)
2750 dentry->d_inode->i_op->put_link(dentry, &nd, cookie);
2751 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002752}
2753
2754int vfs_follow_link(struct nameidata *nd, const char *link)
2755{
2756 return __vfs_follow_link(nd, link);
2757}
2758
2759/* get the link contents into pagecache */
2760static char *page_getlink(struct dentry * dentry, struct page **ppage)
2761{
2762 struct page * page;
2763 struct address_space *mapping = dentry->d_inode->i_mapping;
Pekka Enberg090d2b12006-06-23 02:05:08 -07002764 page = read_mapping_page(mapping, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002765 if (IS_ERR(page))
Nick Piggin6fe69002007-05-06 14:49:04 -07002766 return (char*)page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002767 *ppage = page;
2768 return kmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002769}
2770
2771int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
2772{
2773 struct page *page = NULL;
2774 char *s = page_getlink(dentry, &page);
2775 int res = vfs_readlink(dentry,buffer,buflen,s);
2776 if (page) {
2777 kunmap(page);
2778 page_cache_release(page);
2779 }
2780 return res;
2781}
2782
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002783void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002784{
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002785 struct page *page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002786 nd_set_link(nd, page_getlink(dentry, &page));
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002787 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002788}
2789
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002790void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002791{
Linus Torvaldscc314ee2005-08-19 18:02:56 -07002792 struct page *page = cookie;
2793
2794 if (page) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002795 kunmap(page);
2796 page_cache_release(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002797 }
2798}
2799
Kirill Korotaev0adb25d2006-03-11 03:27:13 -08002800int __page_symlink(struct inode *inode, const char *symname, int len,
2801 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002802{
2803 struct address_space *mapping = inode->i_mapping;
Kirill Korotaev0adb25d2006-03-11 03:27:13 -08002804 struct page *page;
Nick Pigginafddba42007-10-16 01:25:01 -07002805 void *fsdata;
Dmitriy Monakhovbeb497a2007-02-16 01:27:18 -08002806 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002807 char *kaddr;
2808
NeilBrown7e53cac2006-03-25 03:07:57 -08002809retry:
Nick Pigginafddba42007-10-16 01:25:01 -07002810 err = pagecache_write_begin(NULL, mapping, 0, len-1,
2811 AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002812 if (err)
Nick Pigginafddba42007-10-16 01:25:01 -07002813 goto fail;
2814
Linus Torvalds1da177e2005-04-16 15:20:36 -07002815 kaddr = kmap_atomic(page, KM_USER0);
2816 memcpy(kaddr, symname, len-1);
2817 kunmap_atomic(kaddr, KM_USER0);
Nick Pigginafddba42007-10-16 01:25:01 -07002818
2819 err = pagecache_write_end(NULL, mapping, 0, len-1, len-1,
2820 page, fsdata);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002821 if (err < 0)
2822 goto fail;
Nick Pigginafddba42007-10-16 01:25:01 -07002823 if (err < len-1)
2824 goto retry;
2825
Linus Torvalds1da177e2005-04-16 15:20:36 -07002826 mark_inode_dirty(inode);
2827 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002828fail:
2829 return err;
2830}
2831
Kirill Korotaev0adb25d2006-03-11 03:27:13 -08002832int page_symlink(struct inode *inode, const char *symname, int len)
2833{
2834 return __page_symlink(inode, symname, len,
2835 mapping_gfp_mask(inode->i_mapping));
2836}
2837
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -08002838const struct inode_operations page_symlink_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002839 .readlink = generic_readlink,
2840 .follow_link = page_follow_link_light,
2841 .put_link = page_put_link,
2842};
2843
Al Viro2d8f3032008-07-22 09:59:21 -04002844EXPORT_SYMBOL(user_path_at);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002845EXPORT_SYMBOL(follow_down);
2846EXPORT_SYMBOL(follow_up);
2847EXPORT_SYMBOL(get_write_access); /* binfmt_aout */
2848EXPORT_SYMBOL(getname);
2849EXPORT_SYMBOL(lock_rename);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002850EXPORT_SYMBOL(lookup_one_len);
2851EXPORT_SYMBOL(page_follow_link_light);
2852EXPORT_SYMBOL(page_put_link);
2853EXPORT_SYMBOL(page_readlink);
Kirill Korotaev0adb25d2006-03-11 03:27:13 -08002854EXPORT_SYMBOL(__page_symlink);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002855EXPORT_SYMBOL(page_symlink);
2856EXPORT_SYMBOL(page_symlink_inode_operations);
2857EXPORT_SYMBOL(path_lookup);
Josef 'Jeff' Sipek16f18202007-07-19 01:48:18 -07002858EXPORT_SYMBOL(vfs_path_lookup);
Al Virof419a2e2008-07-22 00:07:17 -04002859EXPORT_SYMBOL(inode_permission);
Christoph Hellwige4543ed2005-11-08 21:35:04 -08002860EXPORT_SYMBOL(vfs_permission);
Christoph Hellwig8c744fb2005-11-08 21:35:04 -08002861EXPORT_SYMBOL(file_permission);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002862EXPORT_SYMBOL(unlock_rename);
2863EXPORT_SYMBOL(vfs_create);
2864EXPORT_SYMBOL(vfs_follow_link);
2865EXPORT_SYMBOL(vfs_link);
2866EXPORT_SYMBOL(vfs_mkdir);
2867EXPORT_SYMBOL(vfs_mknod);
2868EXPORT_SYMBOL(generic_permission);
2869EXPORT_SYMBOL(vfs_readlink);
2870EXPORT_SYMBOL(vfs_rename);
2871EXPORT_SYMBOL(vfs_rmdir);
2872EXPORT_SYMBOL(vfs_symlink);
2873EXPORT_SYMBOL(vfs_unlink);
2874EXPORT_SYMBOL(dentry_unhash);
2875EXPORT_SYMBOL(generic_readlink);