Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/namei.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * Some corrections by tytso. | |
9 | */ | |
10 | ||
11 | /* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname | |
12 | * lookup logic. | |
13 | */ | |
14 | /* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture. | |
15 | */ | |
16 | ||
17 | #include <linux/init.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/namei.h> | |
22 | #include <linux/quotaops.h> | |
23 | #include <linux/pagemap.h> | |
0eeca283 | 24 | #include <linux/fsnotify.h> |
1da177e4 LT |
25 | #include <linux/personality.h> |
26 | #include <linux/security.h> | |
27 | #include <linux/syscalls.h> | |
28 | #include <linux/mount.h> | |
29 | #include <linux/audit.h> | |
16f7e0fe | 30 | #include <linux/capability.h> |
834f2a4a | 31 | #include <linux/file.h> |
5590ff0d UD |
32 | #include <linux/fcntl.h> |
33 | #include <linux/namei.h> | |
1da177e4 LT |
34 | #include <asm/namei.h> |
35 | #include <asm/uaccess.h> | |
36 | ||
37 | #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE]) | |
38 | ||
39 | /* [Feb-1997 T. Schoebel-Theuer] | |
40 | * Fundamental changes in the pathname lookup mechanisms (namei) | |
41 | * were necessary because of omirr. The reason is that omirr needs | |
42 | * to know the _real_ pathname, not the user-supplied one, in case | |
43 | * of symlinks (and also when transname replacements occur). | |
44 | * | |
45 | * The new code replaces the old recursive symlink resolution with | |
46 | * an iterative one (in case of non-nested symlink chains). It does | |
47 | * this with calls to <fs>_follow_link(). | |
48 | * As a side effect, dir_namei(), _namei() and follow_link() are now | |
49 | * replaced with a single function lookup_dentry() that can handle all | |
50 | * the special cases of the former code. | |
51 | * | |
52 | * With the new dcache, the pathname is stored at each inode, at least as | |
53 | * long as the refcount of the inode is positive. As a side effect, the | |
54 | * size of the dcache depends on the inode cache and thus is dynamic. | |
55 | * | |
56 | * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink | |
57 | * resolution to correspond with current state of the code. | |
58 | * | |
59 | * Note that the symlink resolution is not *completely* iterative. | |
60 | * There is still a significant amount of tail- and mid- recursion in | |
61 | * the algorithm. Also, note that <fs>_readlink() is not used in | |
62 | * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() | |
63 | * may return different results than <fs>_follow_link(). Many virtual | |
64 | * filesystems (including /proc) exhibit this behavior. | |
65 | */ | |
66 | ||
67 | /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: | |
68 | * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL | |
69 | * and the name already exists in form of a symlink, try to create the new | |
70 | * name indicated by the symlink. The old code always complained that the | |
71 | * name already exists, due to not following the symlink even if its target | |
72 | * is nonexistent. The new semantics affects also mknod() and link() when | |
73 | * the name is a symlink pointing to a non-existant name. | |
74 | * | |
75 | * I don't know which semantics is the right one, since I have no access | |
76 | * to standards. But I found by trial that HP-UX 9.0 has the full "new" | |
77 | * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the | |
78 | * "old" one. Personally, I think the new semantics is much more logical. | |
79 | * Note that "ln old new" where "new" is a symlink pointing to a non-existing | |
80 | * file does succeed in both HP-UX and SunOs, but not in Solaris | |
81 | * and in the old Linux semantics. | |
82 | */ | |
83 | ||
84 | /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink | |
85 | * semantics. See the comments in "open_namei" and "do_link" below. | |
86 | * | |
87 | * [10-Sep-98 Alan Modra] Another symlink change. | |
88 | */ | |
89 | ||
90 | /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: | |
91 | * inside the path - always follow. | |
92 | * in the last component in creation/removal/renaming - never follow. | |
93 | * if LOOKUP_FOLLOW passed - follow. | |
94 | * if the pathname has trailing slashes - follow. | |
95 | * otherwise - don't follow. | |
96 | * (applied in that order). | |
97 | * | |
98 | * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT | |
99 | * restored for 2.4. This is the last surviving part of old 4.2BSD bug. | |
100 | * During the 2.4 we need to fix the userland stuff depending on it - | |
101 | * hopefully we will be able to get rid of that wart in 2.5. So far only | |
102 | * XEmacs seems to be relying on it... | |
103 | */ | |
104 | /* | |
105 | * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland) | |
a11f3a05 | 106 | * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives |
1da177e4 LT |
107 | * any extra contention... |
108 | */ | |
109 | ||
110 | /* In order to reduce some races, while at the same time doing additional | |
111 | * checking and hopefully speeding things up, we copy filenames to the | |
112 | * kernel data space before using them.. | |
113 | * | |
114 | * POSIX.1 2.4: an empty pathname is invalid (ENOENT). | |
115 | * PATH_MAX includes the nul terminator --RR. | |
116 | */ | |
858119e1 | 117 | static int do_getname(const char __user *filename, char *page) |
1da177e4 LT |
118 | { |
119 | int retval; | |
120 | unsigned long len = PATH_MAX; | |
121 | ||
122 | if (!segment_eq(get_fs(), KERNEL_DS)) { | |
123 | if ((unsigned long) filename >= TASK_SIZE) | |
124 | return -EFAULT; | |
125 | if (TASK_SIZE - (unsigned long) filename < PATH_MAX) | |
126 | len = TASK_SIZE - (unsigned long) filename; | |
127 | } | |
128 | ||
129 | retval = strncpy_from_user(page, filename, len); | |
130 | if (retval > 0) { | |
131 | if (retval < len) | |
132 | return 0; | |
133 | return -ENAMETOOLONG; | |
134 | } else if (!retval) | |
135 | retval = -ENOENT; | |
136 | return retval; | |
137 | } | |
138 | ||
139 | char * getname(const char __user * filename) | |
140 | { | |
141 | char *tmp, *result; | |
142 | ||
143 | result = ERR_PTR(-ENOMEM); | |
144 | tmp = __getname(); | |
145 | if (tmp) { | |
146 | int retval = do_getname(filename, tmp); | |
147 | ||
148 | result = tmp; | |
149 | if (retval < 0) { | |
150 | __putname(tmp); | |
151 | result = ERR_PTR(retval); | |
152 | } | |
153 | } | |
154 | audit_getname(result); | |
155 | return result; | |
156 | } | |
157 | ||
158 | #ifdef CONFIG_AUDITSYSCALL | |
159 | void putname(const char *name) | |
160 | { | |
5ac3a9c2 | 161 | if (unlikely(!audit_dummy_context())) |
1da177e4 LT |
162 | audit_putname(name); |
163 | else | |
164 | __putname(name); | |
165 | } | |
166 | EXPORT_SYMBOL(putname); | |
167 | #endif | |
168 | ||
169 | ||
170 | /** | |
171 | * generic_permission - check for access rights on a Posix-like filesystem | |
172 | * @inode: inode to check access rights for | |
173 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) | |
174 | * @check_acl: optional callback to check for Posix ACLs | |
175 | * | |
176 | * Used to check for read/write/execute permissions on a file. | |
177 | * We use "fsuid" for this, letting us set arbitrary permissions | |
178 | * for filesystem access without changing the "normal" uids which | |
179 | * are used for other things.. | |
180 | */ | |
181 | int generic_permission(struct inode *inode, int mask, | |
182 | int (*check_acl)(struct inode *inode, int mask)) | |
183 | { | |
184 | umode_t mode = inode->i_mode; | |
185 | ||
186 | if (current->fsuid == inode->i_uid) | |
187 | mode >>= 6; | |
188 | else { | |
189 | if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) { | |
190 | int error = check_acl(inode, mask); | |
191 | if (error == -EACCES) | |
192 | goto check_capabilities; | |
193 | else if (error != -EAGAIN) | |
194 | return error; | |
195 | } | |
196 | ||
197 | if (in_group_p(inode->i_gid)) | |
198 | mode >>= 3; | |
199 | } | |
200 | ||
201 | /* | |
202 | * If the DACs are ok we don't need any capability check. | |
203 | */ | |
204 | if (((mode & mask & (MAY_READ|MAY_WRITE|MAY_EXEC)) == mask)) | |
205 | return 0; | |
206 | ||
207 | check_capabilities: | |
208 | /* | |
209 | * Read/write DACs are always overridable. | |
210 | * Executable DACs are overridable if at least one exec bit is set. | |
211 | */ | |
212 | if (!(mask & MAY_EXEC) || | |
213 | (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode)) | |
214 | if (capable(CAP_DAC_OVERRIDE)) | |
215 | return 0; | |
216 | ||
217 | /* | |
218 | * Searching includes executable on directories, else just read. | |
219 | */ | |
220 | if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) | |
221 | if (capable(CAP_DAC_READ_SEARCH)) | |
222 | return 0; | |
223 | ||
224 | return -EACCES; | |
225 | } | |
226 | ||
227 | int permission(struct inode *inode, int mask, struct nameidata *nd) | |
228 | { | |
a343bb77 | 229 | umode_t mode = inode->i_mode; |
1da177e4 LT |
230 | int retval, submask; |
231 | ||
232 | if (mask & MAY_WRITE) { | |
1da177e4 LT |
233 | |
234 | /* | |
235 | * Nobody gets write access to a read-only fs. | |
236 | */ | |
237 | if (IS_RDONLY(inode) && | |
238 | (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) | |
239 | return -EROFS; | |
240 | ||
241 | /* | |
242 | * Nobody gets write access to an immutable file. | |
243 | */ | |
244 | if (IS_IMMUTABLE(inode)) | |
245 | return -EACCES; | |
246 | } | |
247 | ||
248 | ||
a343bb77 TM |
249 | /* |
250 | * MAY_EXEC on regular files requires special handling: We override | |
317a40ac SS |
251 | * filesystem execute permissions if the mode bits aren't set or |
252 | * the fs is mounted with the "noexec" flag. | |
a343bb77 | 253 | */ |
317a40ac SS |
254 | if ((mask & MAY_EXEC) && S_ISREG(mode) && (!(mode & S_IXUGO) || |
255 | (nd && nd->mnt && (nd->mnt->mnt_flags & MNT_NOEXEC)))) | |
a343bb77 TM |
256 | return -EACCES; |
257 | ||
1da177e4 LT |
258 | /* Ordinary permission routines do not understand MAY_APPEND. */ |
259 | submask = mask & ~MAY_APPEND; | |
260 | if (inode->i_op && inode->i_op->permission) | |
261 | retval = inode->i_op->permission(inode, submask, nd); | |
262 | else | |
263 | retval = generic_permission(inode, submask, NULL); | |
264 | if (retval) | |
265 | return retval; | |
266 | ||
267 | return security_inode_permission(inode, mask, nd); | |
268 | } | |
269 | ||
e4543edd CH |
270 | /** |
271 | * vfs_permission - check for access rights to a given path | |
272 | * @nd: lookup result that describes the path | |
273 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) | |
274 | * | |
275 | * Used to check for read/write/execute permissions on a path. | |
276 | * We use "fsuid" for this, letting us set arbitrary permissions | |
277 | * for filesystem access without changing the "normal" uids which | |
278 | * are used for other things. | |
279 | */ | |
280 | int vfs_permission(struct nameidata *nd, int mask) | |
281 | { | |
282 | return permission(nd->dentry->d_inode, mask, nd); | |
283 | } | |
284 | ||
8c744fb8 CH |
285 | /** |
286 | * file_permission - check for additional access rights to a given file | |
287 | * @file: file to check access rights for | |
288 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) | |
289 | * | |
290 | * Used to check for read/write/execute permissions on an already opened | |
291 | * file. | |
292 | * | |
293 | * Note: | |
294 | * Do not use this function in new code. All access checks should | |
295 | * be done using vfs_permission(). | |
296 | */ | |
297 | int file_permission(struct file *file, int mask) | |
298 | { | |
0f7fc9e4 | 299 | return permission(file->f_path.dentry->d_inode, mask, NULL); |
8c744fb8 CH |
300 | } |
301 | ||
1da177e4 LT |
302 | /* |
303 | * get_write_access() gets write permission for a file. | |
304 | * put_write_access() releases this write permission. | |
305 | * This is used for regular files. | |
306 | * We cannot support write (and maybe mmap read-write shared) accesses and | |
307 | * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode | |
308 | * can have the following values: | |
309 | * 0: no writers, no VM_DENYWRITE mappings | |
310 | * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist | |
311 | * > 0: (i_writecount) users are writing to the file. | |
312 | * | |
313 | * Normally we operate on that counter with atomic_{inc,dec} and it's safe | |
314 | * except for the cases where we don't hold i_writecount yet. Then we need to | |
315 | * use {get,deny}_write_access() - these functions check the sign and refuse | |
316 | * to do the change if sign is wrong. Exclusion between them is provided by | |
317 | * the inode->i_lock spinlock. | |
318 | */ | |
319 | ||
320 | int get_write_access(struct inode * inode) | |
321 | { | |
322 | spin_lock(&inode->i_lock); | |
323 | if (atomic_read(&inode->i_writecount) < 0) { | |
324 | spin_unlock(&inode->i_lock); | |
325 | return -ETXTBSY; | |
326 | } | |
327 | atomic_inc(&inode->i_writecount); | |
328 | spin_unlock(&inode->i_lock); | |
329 | ||
330 | return 0; | |
331 | } | |
332 | ||
333 | int deny_write_access(struct file * file) | |
334 | { | |
0f7fc9e4 | 335 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
336 | |
337 | spin_lock(&inode->i_lock); | |
338 | if (atomic_read(&inode->i_writecount) > 0) { | |
339 | spin_unlock(&inode->i_lock); | |
340 | return -ETXTBSY; | |
341 | } | |
342 | atomic_dec(&inode->i_writecount); | |
343 | spin_unlock(&inode->i_lock); | |
344 | ||
345 | return 0; | |
346 | } | |
347 | ||
348 | void path_release(struct nameidata *nd) | |
349 | { | |
350 | dput(nd->dentry); | |
351 | mntput(nd->mnt); | |
352 | } | |
353 | ||
354 | /* | |
355 | * umount() mustn't call path_release()/mntput() as that would clear | |
356 | * mnt_expiry_mark | |
357 | */ | |
358 | void path_release_on_umount(struct nameidata *nd) | |
359 | { | |
360 | dput(nd->dentry); | |
751c404b | 361 | mntput_no_expire(nd->mnt); |
1da177e4 LT |
362 | } |
363 | ||
834f2a4a TM |
364 | /** |
365 | * release_open_intent - free up open intent resources | |
366 | * @nd: pointer to nameidata | |
367 | */ | |
368 | void release_open_intent(struct nameidata *nd) | |
369 | { | |
0f7fc9e4 | 370 | if (nd->intent.open.file->f_path.dentry == NULL) |
834f2a4a TM |
371 | put_filp(nd->intent.open.file); |
372 | else | |
373 | fput(nd->intent.open.file); | |
374 | } | |
375 | ||
bcdc5e01 IK |
376 | static inline struct dentry * |
377 | do_revalidate(struct dentry *dentry, struct nameidata *nd) | |
378 | { | |
379 | int status = dentry->d_op->d_revalidate(dentry, nd); | |
380 | if (unlikely(status <= 0)) { | |
381 | /* | |
382 | * The dentry failed validation. | |
383 | * If d_revalidate returned 0 attempt to invalidate | |
384 | * the dentry otherwise d_revalidate is asking us | |
385 | * to return a fail status. | |
386 | */ | |
387 | if (!status) { | |
388 | if (!d_invalidate(dentry)) { | |
389 | dput(dentry); | |
390 | dentry = NULL; | |
391 | } | |
392 | } else { | |
393 | dput(dentry); | |
394 | dentry = ERR_PTR(status); | |
395 | } | |
396 | } | |
397 | return dentry; | |
398 | } | |
399 | ||
1da177e4 LT |
400 | /* |
401 | * Internal lookup() using the new generic dcache. | |
402 | * SMP-safe | |
403 | */ | |
404 | static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) | |
405 | { | |
406 | struct dentry * dentry = __d_lookup(parent, name); | |
407 | ||
408 | /* lockess __d_lookup may fail due to concurrent d_move() | |
409 | * in some unrelated directory, so try with d_lookup | |
410 | */ | |
411 | if (!dentry) | |
412 | dentry = d_lookup(parent, name); | |
413 | ||
bcdc5e01 IK |
414 | if (dentry && dentry->d_op && dentry->d_op->d_revalidate) |
415 | dentry = do_revalidate(dentry, nd); | |
416 | ||
1da177e4 LT |
417 | return dentry; |
418 | } | |
419 | ||
420 | /* | |
421 | * Short-cut version of permission(), for calling by | |
422 | * path_walk(), when dcache lock is held. Combines parts | |
423 | * of permission() and generic_permission(), and tests ONLY for | |
424 | * MAY_EXEC permission. | |
425 | * | |
426 | * If appropriate, check DAC only. If not appropriate, or | |
427 | * short-cut DAC fails, then call permission() to do more | |
428 | * complete permission check. | |
429 | */ | |
858119e1 | 430 | static int exec_permission_lite(struct inode *inode, |
1da177e4 LT |
431 | struct nameidata *nd) |
432 | { | |
433 | umode_t mode = inode->i_mode; | |
434 | ||
435 | if (inode->i_op && inode->i_op->permission) | |
436 | return -EAGAIN; | |
437 | ||
438 | if (current->fsuid == inode->i_uid) | |
439 | mode >>= 6; | |
440 | else if (in_group_p(inode->i_gid)) | |
441 | mode >>= 3; | |
442 | ||
443 | if (mode & MAY_EXEC) | |
444 | goto ok; | |
445 | ||
446 | if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE)) | |
447 | goto ok; | |
448 | ||
449 | if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE)) | |
450 | goto ok; | |
451 | ||
452 | if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH)) | |
453 | goto ok; | |
454 | ||
455 | return -EACCES; | |
456 | ok: | |
457 | return security_inode_permission(inode, MAY_EXEC, nd); | |
458 | } | |
459 | ||
460 | /* | |
461 | * This is called when everything else fails, and we actually have | |
462 | * to go to the low-level filesystem to find out what we should do.. | |
463 | * | |
464 | * We get the directory semaphore, and after getting that we also | |
465 | * make sure that nobody added the entry to the dcache in the meantime.. | |
466 | * SMP-safe | |
467 | */ | |
468 | static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) | |
469 | { | |
470 | struct dentry * result; | |
471 | struct inode *dir = parent->d_inode; | |
472 | ||
1b1dcc1b | 473 | mutex_lock(&dir->i_mutex); |
1da177e4 LT |
474 | /* |
475 | * First re-do the cached lookup just in case it was created | |
476 | * while we waited for the directory semaphore.. | |
477 | * | |
478 | * FIXME! This could use version numbering or similar to | |
479 | * avoid unnecessary cache lookups. | |
480 | * | |
481 | * The "dcache_lock" is purely to protect the RCU list walker | |
482 | * from concurrent renames at this point (we mustn't get false | |
483 | * negatives from the RCU list walk here, unlike the optimistic | |
484 | * fast walk). | |
485 | * | |
486 | * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup | |
487 | */ | |
488 | result = d_lookup(parent, name); | |
489 | if (!result) { | |
490 | struct dentry * dentry = d_alloc(parent, name); | |
491 | result = ERR_PTR(-ENOMEM); | |
492 | if (dentry) { | |
493 | result = dir->i_op->lookup(dir, dentry, nd); | |
494 | if (result) | |
495 | dput(dentry); | |
496 | else | |
497 | result = dentry; | |
498 | } | |
1b1dcc1b | 499 | mutex_unlock(&dir->i_mutex); |
1da177e4 LT |
500 | return result; |
501 | } | |
502 | ||
503 | /* | |
504 | * Uhhuh! Nasty case: the cache was re-populated while | |
505 | * we waited on the semaphore. Need to revalidate. | |
506 | */ | |
1b1dcc1b | 507 | mutex_unlock(&dir->i_mutex); |
1da177e4 | 508 | if (result->d_op && result->d_op->d_revalidate) { |
bcdc5e01 IK |
509 | result = do_revalidate(result, nd); |
510 | if (!result) | |
1da177e4 | 511 | result = ERR_PTR(-ENOENT); |
1da177e4 LT |
512 | } |
513 | return result; | |
514 | } | |
515 | ||
516 | static int __emul_lookup_dentry(const char *, struct nameidata *); | |
517 | ||
518 | /* SMP-safe */ | |
f1662356 | 519 | static __always_inline int |
1da177e4 LT |
520 | walk_init_root(const char *name, struct nameidata *nd) |
521 | { | |
e518ddb7 AM |
522 | struct fs_struct *fs = current->fs; |
523 | ||
524 | read_lock(&fs->lock); | |
525 | if (fs->altroot && !(nd->flags & LOOKUP_NOALT)) { | |
526 | nd->mnt = mntget(fs->altrootmnt); | |
527 | nd->dentry = dget(fs->altroot); | |
528 | read_unlock(&fs->lock); | |
1da177e4 LT |
529 | if (__emul_lookup_dentry(name,nd)) |
530 | return 0; | |
e518ddb7 | 531 | read_lock(&fs->lock); |
1da177e4 | 532 | } |
e518ddb7 AM |
533 | nd->mnt = mntget(fs->rootmnt); |
534 | nd->dentry = dget(fs->root); | |
535 | read_unlock(&fs->lock); | |
1da177e4 LT |
536 | return 1; |
537 | } | |
538 | ||
f1662356 | 539 | static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) |
1da177e4 LT |
540 | { |
541 | int res = 0; | |
542 | char *name; | |
543 | if (IS_ERR(link)) | |
544 | goto fail; | |
545 | ||
546 | if (*link == '/') { | |
547 | path_release(nd); | |
548 | if (!walk_init_root(link, nd)) | |
549 | /* weird __emul_prefix() stuff did it */ | |
550 | goto out; | |
551 | } | |
552 | res = link_path_walk(link, nd); | |
553 | out: | |
554 | if (nd->depth || res || nd->last_type!=LAST_NORM) | |
555 | return res; | |
556 | /* | |
557 | * If it is an iterative symlinks resolution in open_namei() we | |
558 | * have to copy the last component. And all that crap because of | |
559 | * bloody create() on broken symlinks. Furrfu... | |
560 | */ | |
561 | name = __getname(); | |
562 | if (unlikely(!name)) { | |
563 | path_release(nd); | |
564 | return -ENOMEM; | |
565 | } | |
566 | strcpy(name, nd->last.name); | |
567 | nd->last.name = name; | |
568 | return 0; | |
569 | fail: | |
570 | path_release(nd); | |
571 | return PTR_ERR(link); | |
572 | } | |
573 | ||
051d3812 IK |
574 | static inline void dput_path(struct path *path, struct nameidata *nd) |
575 | { | |
576 | dput(path->dentry); | |
577 | if (path->mnt != nd->mnt) | |
578 | mntput(path->mnt); | |
579 | } | |
580 | ||
581 | static inline void path_to_nameidata(struct path *path, struct nameidata *nd) | |
582 | { | |
583 | dput(nd->dentry); | |
584 | if (nd->mnt != path->mnt) | |
585 | mntput(nd->mnt); | |
586 | nd->mnt = path->mnt; | |
587 | nd->dentry = path->dentry; | |
588 | } | |
589 | ||
f1662356 | 590 | static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd) |
1da177e4 LT |
591 | { |
592 | int error; | |
cc314eef | 593 | void *cookie; |
cd4e91d3 | 594 | struct dentry *dentry = path->dentry; |
1da177e4 | 595 | |
d671a1cb | 596 | touch_atime(path->mnt, dentry); |
1da177e4 | 597 | nd_set_link(nd, NULL); |
cd4e91d3 | 598 | |
051d3812 IK |
599 | if (path->mnt != nd->mnt) { |
600 | path_to_nameidata(path, nd); | |
601 | dget(dentry); | |
602 | } | |
603 | mntget(path->mnt); | |
cc314eef LT |
604 | cookie = dentry->d_inode->i_op->follow_link(dentry, nd); |
605 | error = PTR_ERR(cookie); | |
606 | if (!IS_ERR(cookie)) { | |
1da177e4 | 607 | char *s = nd_get_link(nd); |
cc314eef | 608 | error = 0; |
1da177e4 LT |
609 | if (s) |
610 | error = __vfs_follow_link(nd, s); | |
611 | if (dentry->d_inode->i_op->put_link) | |
cc314eef | 612 | dentry->d_inode->i_op->put_link(dentry, nd, cookie); |
1da177e4 | 613 | } |
cd4e91d3 AV |
614 | dput(dentry); |
615 | mntput(path->mnt); | |
1da177e4 LT |
616 | |
617 | return error; | |
618 | } | |
619 | ||
620 | /* | |
621 | * This limits recursive symlink follows to 8, while | |
622 | * limiting consecutive symlinks to 40. | |
623 | * | |
624 | * Without that kind of total limit, nasty chains of consecutive | |
625 | * symlinks can cause almost arbitrarily long lookups. | |
626 | */ | |
90ebe565 | 627 | static inline int do_follow_link(struct path *path, struct nameidata *nd) |
1da177e4 LT |
628 | { |
629 | int err = -ELOOP; | |
630 | if (current->link_count >= MAX_NESTED_LINKS) | |
631 | goto loop; | |
632 | if (current->total_link_count >= 40) | |
633 | goto loop; | |
634 | BUG_ON(nd->depth >= MAX_NESTED_LINKS); | |
635 | cond_resched(); | |
90ebe565 | 636 | err = security_inode_follow_link(path->dentry, nd); |
1da177e4 LT |
637 | if (err) |
638 | goto loop; | |
639 | current->link_count++; | |
640 | current->total_link_count++; | |
641 | nd->depth++; | |
cd4e91d3 | 642 | err = __do_follow_link(path, nd); |
839d9f93 AV |
643 | current->link_count--; |
644 | nd->depth--; | |
1da177e4 LT |
645 | return err; |
646 | loop: | |
09dd17d3 | 647 | dput_path(path, nd); |
839d9f93 | 648 | path_release(nd); |
1da177e4 LT |
649 | return err; |
650 | } | |
651 | ||
652 | int follow_up(struct vfsmount **mnt, struct dentry **dentry) | |
653 | { | |
654 | struct vfsmount *parent; | |
655 | struct dentry *mountpoint; | |
656 | spin_lock(&vfsmount_lock); | |
657 | parent=(*mnt)->mnt_parent; | |
658 | if (parent == *mnt) { | |
659 | spin_unlock(&vfsmount_lock); | |
660 | return 0; | |
661 | } | |
662 | mntget(parent); | |
663 | mountpoint=dget((*mnt)->mnt_mountpoint); | |
664 | spin_unlock(&vfsmount_lock); | |
665 | dput(*dentry); | |
666 | *dentry = mountpoint; | |
667 | mntput(*mnt); | |
668 | *mnt = parent; | |
669 | return 1; | |
670 | } | |
671 | ||
672 | /* no need for dcache_lock, as serialization is taken care in | |
673 | * namespace.c | |
674 | */ | |
463ffb2e AV |
675 | static int __follow_mount(struct path *path) |
676 | { | |
677 | int res = 0; | |
678 | while (d_mountpoint(path->dentry)) { | |
679 | struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry); | |
680 | if (!mounted) | |
681 | break; | |
682 | dput(path->dentry); | |
683 | if (res) | |
684 | mntput(path->mnt); | |
685 | path->mnt = mounted; | |
686 | path->dentry = dget(mounted->mnt_root); | |
687 | res = 1; | |
688 | } | |
689 | return res; | |
690 | } | |
691 | ||
58c465eb | 692 | static void follow_mount(struct vfsmount **mnt, struct dentry **dentry) |
1da177e4 | 693 | { |
1da177e4 LT |
694 | while (d_mountpoint(*dentry)) { |
695 | struct vfsmount *mounted = lookup_mnt(*mnt, *dentry); | |
696 | if (!mounted) | |
697 | break; | |
58c465eb | 698 | dput(*dentry); |
1da177e4 LT |
699 | mntput(*mnt); |
700 | *mnt = mounted; | |
1da177e4 | 701 | *dentry = dget(mounted->mnt_root); |
1da177e4 | 702 | } |
1da177e4 LT |
703 | } |
704 | ||
705 | /* no need for dcache_lock, as serialization is taken care in | |
706 | * namespace.c | |
707 | */ | |
e13b210f | 708 | int follow_down(struct vfsmount **mnt, struct dentry **dentry) |
1da177e4 LT |
709 | { |
710 | struct vfsmount *mounted; | |
711 | ||
712 | mounted = lookup_mnt(*mnt, *dentry); | |
713 | if (mounted) { | |
e13b210f | 714 | dput(*dentry); |
1da177e4 LT |
715 | mntput(*mnt); |
716 | *mnt = mounted; | |
1da177e4 LT |
717 | *dentry = dget(mounted->mnt_root); |
718 | return 1; | |
719 | } | |
720 | return 0; | |
721 | } | |
722 | ||
f1662356 | 723 | static __always_inline void follow_dotdot(struct nameidata *nd) |
1da177e4 | 724 | { |
e518ddb7 AM |
725 | struct fs_struct *fs = current->fs; |
726 | ||
1da177e4 LT |
727 | while(1) { |
728 | struct vfsmount *parent; | |
58c465eb | 729 | struct dentry *old = nd->dentry; |
1da177e4 | 730 | |
e518ddb7 AM |
731 | read_lock(&fs->lock); |
732 | if (nd->dentry == fs->root && | |
733 | nd->mnt == fs->rootmnt) { | |
734 | read_unlock(&fs->lock); | |
1da177e4 LT |
735 | break; |
736 | } | |
e518ddb7 | 737 | read_unlock(&fs->lock); |
1da177e4 | 738 | spin_lock(&dcache_lock); |
58c465eb AV |
739 | if (nd->dentry != nd->mnt->mnt_root) { |
740 | nd->dentry = dget(nd->dentry->d_parent); | |
1da177e4 LT |
741 | spin_unlock(&dcache_lock); |
742 | dput(old); | |
743 | break; | |
744 | } | |
745 | spin_unlock(&dcache_lock); | |
746 | spin_lock(&vfsmount_lock); | |
58c465eb AV |
747 | parent = nd->mnt->mnt_parent; |
748 | if (parent == nd->mnt) { | |
1da177e4 LT |
749 | spin_unlock(&vfsmount_lock); |
750 | break; | |
751 | } | |
752 | mntget(parent); | |
58c465eb | 753 | nd->dentry = dget(nd->mnt->mnt_mountpoint); |
1da177e4 LT |
754 | spin_unlock(&vfsmount_lock); |
755 | dput(old); | |
58c465eb AV |
756 | mntput(nd->mnt); |
757 | nd->mnt = parent; | |
1da177e4 | 758 | } |
58c465eb | 759 | follow_mount(&nd->mnt, &nd->dentry); |
1da177e4 LT |
760 | } |
761 | ||
1da177e4 LT |
762 | /* |
763 | * It's more convoluted than I'd like it to be, but... it's still fairly | |
764 | * small and for now I'd prefer to have fast path as straight as possible. | |
765 | * It _is_ time-critical. | |
766 | */ | |
767 | static int do_lookup(struct nameidata *nd, struct qstr *name, | |
768 | struct path *path) | |
769 | { | |
770 | struct vfsmount *mnt = nd->mnt; | |
771 | struct dentry *dentry = __d_lookup(nd->dentry, name); | |
772 | ||
773 | if (!dentry) | |
774 | goto need_lookup; | |
775 | if (dentry->d_op && dentry->d_op->d_revalidate) | |
776 | goto need_revalidate; | |
777 | done: | |
778 | path->mnt = mnt; | |
779 | path->dentry = dentry; | |
634ee701 | 780 | __follow_mount(path); |
1da177e4 LT |
781 | return 0; |
782 | ||
783 | need_lookup: | |
784 | dentry = real_lookup(nd->dentry, name, nd); | |
785 | if (IS_ERR(dentry)) | |
786 | goto fail; | |
787 | goto done; | |
788 | ||
789 | need_revalidate: | |
bcdc5e01 IK |
790 | dentry = do_revalidate(dentry, nd); |
791 | if (!dentry) | |
792 | goto need_lookup; | |
793 | if (IS_ERR(dentry)) | |
794 | goto fail; | |
795 | goto done; | |
1da177e4 LT |
796 | |
797 | fail: | |
798 | return PTR_ERR(dentry); | |
799 | } | |
800 | ||
801 | /* | |
802 | * Name resolution. | |
ea3834d9 PM |
803 | * This is the basic name resolution function, turning a pathname into |
804 | * the final dentry. We expect 'base' to be positive and a directory. | |
1da177e4 | 805 | * |
ea3834d9 PM |
806 | * Returns 0 and nd will have valid dentry and mnt on success. |
807 | * Returns error and drops reference to input namei data on failure. | |
1da177e4 LT |
808 | */ |
809 | static fastcall int __link_path_walk(const char * name, struct nameidata *nd) | |
810 | { | |
811 | struct path next; | |
812 | struct inode *inode; | |
813 | int err; | |
814 | unsigned int lookup_flags = nd->flags; | |
815 | ||
816 | while (*name=='/') | |
817 | name++; | |
818 | if (!*name) | |
819 | goto return_reval; | |
820 | ||
821 | inode = nd->dentry->d_inode; | |
822 | if (nd->depth) | |
f55eab82 | 823 | lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE); |
1da177e4 LT |
824 | |
825 | /* At this point we know we have a real path component. */ | |
826 | for(;;) { | |
827 | unsigned long hash; | |
828 | struct qstr this; | |
829 | unsigned int c; | |
830 | ||
cdce5d6b | 831 | nd->flags |= LOOKUP_CONTINUE; |
1da177e4 | 832 | err = exec_permission_lite(inode, nd); |
e4543edd CH |
833 | if (err == -EAGAIN) |
834 | err = vfs_permission(nd, MAY_EXEC); | |
1da177e4 LT |
835 | if (err) |
836 | break; | |
837 | ||
838 | this.name = name; | |
839 | c = *(const unsigned char *)name; | |
840 | ||
841 | hash = init_name_hash(); | |
842 | do { | |
843 | name++; | |
844 | hash = partial_name_hash(c, hash); | |
845 | c = *(const unsigned char *)name; | |
846 | } while (c && (c != '/')); | |
847 | this.len = name - (const char *) this.name; | |
848 | this.hash = end_name_hash(hash); | |
849 | ||
850 | /* remove trailing slashes? */ | |
851 | if (!c) | |
852 | goto last_component; | |
853 | while (*++name == '/'); | |
854 | if (!*name) | |
855 | goto last_with_slashes; | |
856 | ||
857 | /* | |
858 | * "." and ".." are special - ".." especially so because it has | |
859 | * to be able to know about the current root directory and | |
860 | * parent relationships. | |
861 | */ | |
862 | if (this.name[0] == '.') switch (this.len) { | |
863 | default: | |
864 | break; | |
865 | case 2: | |
866 | if (this.name[1] != '.') | |
867 | break; | |
58c465eb | 868 | follow_dotdot(nd); |
1da177e4 LT |
869 | inode = nd->dentry->d_inode; |
870 | /* fallthrough */ | |
871 | case 1: | |
872 | continue; | |
873 | } | |
874 | /* | |
875 | * See if the low-level filesystem might want | |
876 | * to use its own hash.. | |
877 | */ | |
878 | if (nd->dentry->d_op && nd->dentry->d_op->d_hash) { | |
879 | err = nd->dentry->d_op->d_hash(nd->dentry, &this); | |
880 | if (err < 0) | |
881 | break; | |
882 | } | |
1da177e4 LT |
883 | /* This does the actual lookups.. */ |
884 | err = do_lookup(nd, &this, &next); | |
885 | if (err) | |
886 | break; | |
1da177e4 LT |
887 | |
888 | err = -ENOENT; | |
889 | inode = next.dentry->d_inode; | |
890 | if (!inode) | |
891 | goto out_dput; | |
892 | err = -ENOTDIR; | |
893 | if (!inode->i_op) | |
894 | goto out_dput; | |
895 | ||
896 | if (inode->i_op->follow_link) { | |
90ebe565 | 897 | err = do_follow_link(&next, nd); |
1da177e4 LT |
898 | if (err) |
899 | goto return_err; | |
900 | err = -ENOENT; | |
901 | inode = nd->dentry->d_inode; | |
902 | if (!inode) | |
903 | break; | |
904 | err = -ENOTDIR; | |
905 | if (!inode->i_op) | |
906 | break; | |
09dd17d3 MS |
907 | } else |
908 | path_to_nameidata(&next, nd); | |
1da177e4 LT |
909 | err = -ENOTDIR; |
910 | if (!inode->i_op->lookup) | |
911 | break; | |
912 | continue; | |
913 | /* here ends the main loop */ | |
914 | ||
915 | last_with_slashes: | |
916 | lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; | |
917 | last_component: | |
f55eab82 TM |
918 | /* Clear LOOKUP_CONTINUE iff it was previously unset */ |
919 | nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; | |
1da177e4 LT |
920 | if (lookup_flags & LOOKUP_PARENT) |
921 | goto lookup_parent; | |
922 | if (this.name[0] == '.') switch (this.len) { | |
923 | default: | |
924 | break; | |
925 | case 2: | |
926 | if (this.name[1] != '.') | |
927 | break; | |
58c465eb | 928 | follow_dotdot(nd); |
1da177e4 LT |
929 | inode = nd->dentry->d_inode; |
930 | /* fallthrough */ | |
931 | case 1: | |
932 | goto return_reval; | |
933 | } | |
934 | if (nd->dentry->d_op && nd->dentry->d_op->d_hash) { | |
935 | err = nd->dentry->d_op->d_hash(nd->dentry, &this); | |
936 | if (err < 0) | |
937 | break; | |
938 | } | |
939 | err = do_lookup(nd, &this, &next); | |
940 | if (err) | |
941 | break; | |
1da177e4 LT |
942 | inode = next.dentry->d_inode; |
943 | if ((lookup_flags & LOOKUP_FOLLOW) | |
944 | && inode && inode->i_op && inode->i_op->follow_link) { | |
90ebe565 | 945 | err = do_follow_link(&next, nd); |
1da177e4 LT |
946 | if (err) |
947 | goto return_err; | |
948 | inode = nd->dentry->d_inode; | |
09dd17d3 MS |
949 | } else |
950 | path_to_nameidata(&next, nd); | |
1da177e4 LT |
951 | err = -ENOENT; |
952 | if (!inode) | |
953 | break; | |
954 | if (lookup_flags & LOOKUP_DIRECTORY) { | |
955 | err = -ENOTDIR; | |
956 | if (!inode->i_op || !inode->i_op->lookup) | |
957 | break; | |
958 | } | |
959 | goto return_base; | |
960 | lookup_parent: | |
961 | nd->last = this; | |
962 | nd->last_type = LAST_NORM; | |
963 | if (this.name[0] != '.') | |
964 | goto return_base; | |
965 | if (this.len == 1) | |
966 | nd->last_type = LAST_DOT; | |
967 | else if (this.len == 2 && this.name[1] == '.') | |
968 | nd->last_type = LAST_DOTDOT; | |
969 | else | |
970 | goto return_base; | |
971 | return_reval: | |
972 | /* | |
973 | * We bypassed the ordinary revalidation routines. | |
974 | * We may need to check the cached dentry for staleness. | |
975 | */ | |
976 | if (nd->dentry && nd->dentry->d_sb && | |
977 | (nd->dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) { | |
978 | err = -ESTALE; | |
979 | /* Note: we do not d_invalidate() */ | |
980 | if (!nd->dentry->d_op->d_revalidate(nd->dentry, nd)) | |
981 | break; | |
982 | } | |
983 | return_base: | |
984 | return 0; | |
985 | out_dput: | |
09dd17d3 | 986 | dput_path(&next, nd); |
1da177e4 LT |
987 | break; |
988 | } | |
989 | path_release(nd); | |
990 | return_err: | |
991 | return err; | |
992 | } | |
993 | ||
994 | /* | |
995 | * Wrapper to retry pathname resolution whenever the underlying | |
996 | * file system returns an ESTALE. | |
997 | * | |
998 | * Retry the whole path once, forcing real lookup requests | |
999 | * instead of relying on the dcache. | |
1000 | */ | |
1001 | int fastcall link_path_walk(const char *name, struct nameidata *nd) | |
1002 | { | |
1003 | struct nameidata save = *nd; | |
1004 | int result; | |
1005 | ||
1006 | /* make sure the stuff we saved doesn't go away */ | |
1007 | dget(save.dentry); | |
1008 | mntget(save.mnt); | |
1009 | ||
1010 | result = __link_path_walk(name, nd); | |
1011 | if (result == -ESTALE) { | |
1012 | *nd = save; | |
1013 | dget(nd->dentry); | |
1014 | mntget(nd->mnt); | |
1015 | nd->flags |= LOOKUP_REVAL; | |
1016 | result = __link_path_walk(name, nd); | |
1017 | } | |
1018 | ||
1019 | dput(save.dentry); | |
1020 | mntput(save.mnt); | |
1021 | ||
1022 | return result; | |
1023 | } | |
1024 | ||
1025 | int fastcall path_walk(const char * name, struct nameidata *nd) | |
1026 | { | |
1027 | current->total_link_count = 0; | |
1028 | return link_path_walk(name, nd); | |
1029 | } | |
1030 | ||
ea3834d9 PM |
1031 | /* |
1032 | * SMP-safe: Returns 1 and nd will have valid dentry and mnt, if | |
1033 | * everything is done. Returns 0 and drops input nd, if lookup failed; | |
1034 | */ | |
1da177e4 LT |
1035 | static int __emul_lookup_dentry(const char *name, struct nameidata *nd) |
1036 | { | |
1037 | if (path_walk(name, nd)) | |
1038 | return 0; /* something went wrong... */ | |
1039 | ||
1040 | if (!nd->dentry->d_inode || S_ISDIR(nd->dentry->d_inode->i_mode)) { | |
1041 | struct dentry *old_dentry = nd->dentry; | |
1042 | struct vfsmount *old_mnt = nd->mnt; | |
1043 | struct qstr last = nd->last; | |
1044 | int last_type = nd->last_type; | |
e518ddb7 AM |
1045 | struct fs_struct *fs = current->fs; |
1046 | ||
1da177e4 | 1047 | /* |
e518ddb7 AM |
1048 | * NAME was not found in alternate root or it's a directory. |
1049 | * Try to find it in the normal root: | |
1da177e4 LT |
1050 | */ |
1051 | nd->last_type = LAST_ROOT; | |
e518ddb7 AM |
1052 | read_lock(&fs->lock); |
1053 | nd->mnt = mntget(fs->rootmnt); | |
1054 | nd->dentry = dget(fs->root); | |
1055 | read_unlock(&fs->lock); | |
1da177e4 LT |
1056 | if (path_walk(name, nd) == 0) { |
1057 | if (nd->dentry->d_inode) { | |
1058 | dput(old_dentry); | |
1059 | mntput(old_mnt); | |
1060 | return 1; | |
1061 | } | |
1062 | path_release(nd); | |
1063 | } | |
1064 | nd->dentry = old_dentry; | |
1065 | nd->mnt = old_mnt; | |
1066 | nd->last = last; | |
1067 | nd->last_type = last_type; | |
1068 | } | |
1069 | return 1; | |
1070 | } | |
1071 | ||
1072 | void set_fs_altroot(void) | |
1073 | { | |
1074 | char *emul = __emul_prefix(); | |
1075 | struct nameidata nd; | |
1076 | struct vfsmount *mnt = NULL, *oldmnt; | |
1077 | struct dentry *dentry = NULL, *olddentry; | |
1078 | int err; | |
e518ddb7 | 1079 | struct fs_struct *fs = current->fs; |
1da177e4 LT |
1080 | |
1081 | if (!emul) | |
1082 | goto set_it; | |
1083 | err = path_lookup(emul, LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_NOALT, &nd); | |
1084 | if (!err) { | |
1085 | mnt = nd.mnt; | |
1086 | dentry = nd.dentry; | |
1087 | } | |
1088 | set_it: | |
e518ddb7 AM |
1089 | write_lock(&fs->lock); |
1090 | oldmnt = fs->altrootmnt; | |
1091 | olddentry = fs->altroot; | |
1092 | fs->altrootmnt = mnt; | |
1093 | fs->altroot = dentry; | |
1094 | write_unlock(&fs->lock); | |
1da177e4 LT |
1095 | if (olddentry) { |
1096 | dput(olddentry); | |
1097 | mntput(oldmnt); | |
1098 | } | |
1099 | } | |
1100 | ||
ea3834d9 | 1101 | /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ |
5590ff0d UD |
1102 | static int fastcall do_path_lookup(int dfd, const char *name, |
1103 | unsigned int flags, struct nameidata *nd) | |
1da177e4 | 1104 | { |
ea3834d9 | 1105 | int retval = 0; |
170aa3d0 UD |
1106 | int fput_needed; |
1107 | struct file *file; | |
e518ddb7 | 1108 | struct fs_struct *fs = current->fs; |
1da177e4 LT |
1109 | |
1110 | nd->last_type = LAST_ROOT; /* if there are only slashes... */ | |
1111 | nd->flags = flags; | |
1112 | nd->depth = 0; | |
1113 | ||
1da177e4 | 1114 | if (*name=='/') { |
e518ddb7 AM |
1115 | read_lock(&fs->lock); |
1116 | if (fs->altroot && !(nd->flags & LOOKUP_NOALT)) { | |
1117 | nd->mnt = mntget(fs->altrootmnt); | |
1118 | nd->dentry = dget(fs->altroot); | |
1119 | read_unlock(&fs->lock); | |
1da177e4 | 1120 | if (__emul_lookup_dentry(name,nd)) |
ea3834d9 | 1121 | goto out; /* found in altroot */ |
e518ddb7 | 1122 | read_lock(&fs->lock); |
1da177e4 | 1123 | } |
e518ddb7 AM |
1124 | nd->mnt = mntget(fs->rootmnt); |
1125 | nd->dentry = dget(fs->root); | |
1126 | read_unlock(&fs->lock); | |
5590ff0d | 1127 | } else if (dfd == AT_FDCWD) { |
e518ddb7 AM |
1128 | read_lock(&fs->lock); |
1129 | nd->mnt = mntget(fs->pwdmnt); | |
1130 | nd->dentry = dget(fs->pwd); | |
1131 | read_unlock(&fs->lock); | |
5590ff0d | 1132 | } else { |
5590ff0d UD |
1133 | struct dentry *dentry; |
1134 | ||
1135 | file = fget_light(dfd, &fput_needed); | |
170aa3d0 UD |
1136 | retval = -EBADF; |
1137 | if (!file) | |
6d09bb62 | 1138 | goto out_fail; |
5590ff0d | 1139 | |
0f7fc9e4 | 1140 | dentry = file->f_path.dentry; |
5590ff0d | 1141 | |
170aa3d0 UD |
1142 | retval = -ENOTDIR; |
1143 | if (!S_ISDIR(dentry->d_inode->i_mode)) | |
6d09bb62 | 1144 | goto fput_fail; |
5590ff0d UD |
1145 | |
1146 | retval = file_permission(file, MAY_EXEC); | |
170aa3d0 | 1147 | if (retval) |
6d09bb62 | 1148 | goto fput_fail; |
5590ff0d | 1149 | |
0f7fc9e4 | 1150 | nd->mnt = mntget(file->f_path.mnt); |
5590ff0d UD |
1151 | nd->dentry = dget(dentry); |
1152 | ||
1153 | fput_light(file, fput_needed); | |
1da177e4 | 1154 | } |
1da177e4 LT |
1155 | current->total_link_count = 0; |
1156 | retval = link_path_walk(name, nd); | |
ea3834d9 | 1157 | out: |
3bc8414b | 1158 | if (likely(retval == 0)) { |
5ac3a9c2 | 1159 | if (unlikely(!audit_dummy_context() && nd && nd->dentry && |
3bc8414b | 1160 | nd->dentry->d_inode)) |
9c937dcc | 1161 | audit_inode(name, nd->dentry->d_inode); |
3bc8414b | 1162 | } |
6d09bb62 | 1163 | out_fail: |
170aa3d0 UD |
1164 | return retval; |
1165 | ||
6d09bb62 | 1166 | fput_fail: |
170aa3d0 | 1167 | fput_light(file, fput_needed); |
6d09bb62 | 1168 | goto out_fail; |
1da177e4 LT |
1169 | } |
1170 | ||
5590ff0d UD |
1171 | int fastcall path_lookup(const char *name, unsigned int flags, |
1172 | struct nameidata *nd) | |
1173 | { | |
1174 | return do_path_lookup(AT_FDCWD, name, flags, nd); | |
1175 | } | |
1176 | ||
1177 | static int __path_lookup_intent_open(int dfd, const char *name, | |
1178 | unsigned int lookup_flags, struct nameidata *nd, | |
1179 | int open_flags, int create_mode) | |
834f2a4a TM |
1180 | { |
1181 | struct file *filp = get_empty_filp(); | |
1182 | int err; | |
1183 | ||
1184 | if (filp == NULL) | |
1185 | return -ENFILE; | |
1186 | nd->intent.open.file = filp; | |
1187 | nd->intent.open.flags = open_flags; | |
1188 | nd->intent.open.create_mode = create_mode; | |
5590ff0d | 1189 | err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd); |
834f2a4a TM |
1190 | if (IS_ERR(nd->intent.open.file)) { |
1191 | if (err == 0) { | |
1192 | err = PTR_ERR(nd->intent.open.file); | |
1193 | path_release(nd); | |
1194 | } | |
1195 | } else if (err != 0) | |
1196 | release_open_intent(nd); | |
1197 | return err; | |
1198 | } | |
1199 | ||
1200 | /** | |
1201 | * path_lookup_open - lookup a file path with open intent | |
7045f37b | 1202 | * @dfd: the directory to use as base, or AT_FDCWD |
834f2a4a TM |
1203 | * @name: pointer to file name |
1204 | * @lookup_flags: lookup intent flags | |
1205 | * @nd: pointer to nameidata | |
1206 | * @open_flags: open intent flags | |
1207 | */ | |
5590ff0d | 1208 | int path_lookup_open(int dfd, const char *name, unsigned int lookup_flags, |
834f2a4a TM |
1209 | struct nameidata *nd, int open_flags) |
1210 | { | |
5590ff0d | 1211 | return __path_lookup_intent_open(dfd, name, lookup_flags, nd, |
834f2a4a TM |
1212 | open_flags, 0); |
1213 | } | |
1214 | ||
1215 | /** | |
1216 | * path_lookup_create - lookup a file path with open + create intent | |
7045f37b | 1217 | * @dfd: the directory to use as base, or AT_FDCWD |
834f2a4a TM |
1218 | * @name: pointer to file name |
1219 | * @lookup_flags: lookup intent flags | |
1220 | * @nd: pointer to nameidata | |
1221 | * @open_flags: open intent flags | |
1222 | * @create_mode: create intent flags | |
1223 | */ | |
5590ff0d UD |
1224 | static int path_lookup_create(int dfd, const char *name, |
1225 | unsigned int lookup_flags, struct nameidata *nd, | |
1226 | int open_flags, int create_mode) | |
834f2a4a | 1227 | { |
5590ff0d UD |
1228 | return __path_lookup_intent_open(dfd, name, lookup_flags|LOOKUP_CREATE, |
1229 | nd, open_flags, create_mode); | |
834f2a4a TM |
1230 | } |
1231 | ||
1232 | int __user_path_lookup_open(const char __user *name, unsigned int lookup_flags, | |
1233 | struct nameidata *nd, int open_flags) | |
1234 | { | |
1235 | char *tmp = getname(name); | |
1236 | int err = PTR_ERR(tmp); | |
1237 | ||
1238 | if (!IS_ERR(tmp)) { | |
5590ff0d | 1239 | err = __path_lookup_intent_open(AT_FDCWD, tmp, lookup_flags, nd, open_flags, 0); |
834f2a4a TM |
1240 | putname(tmp); |
1241 | } | |
1242 | return err; | |
1243 | } | |
1244 | ||
057f6c01 | 1245 | static inline struct dentry *__lookup_hash_kern(struct qstr *name, struct dentry *base, struct nameidata *nd) |
1da177e4 | 1246 | { |
057f6c01 | 1247 | struct dentry *dentry; |
1da177e4 LT |
1248 | struct inode *inode; |
1249 | int err; | |
1250 | ||
1251 | inode = base->d_inode; | |
1da177e4 LT |
1252 | |
1253 | /* | |
1254 | * See if the low-level filesystem might want | |
1255 | * to use its own hash.. | |
1256 | */ | |
1257 | if (base->d_op && base->d_op->d_hash) { | |
1258 | err = base->d_op->d_hash(base, name); | |
1259 | dentry = ERR_PTR(err); | |
1260 | if (err < 0) | |
1261 | goto out; | |
1262 | } | |
1263 | ||
1264 | dentry = cached_lookup(base, name, nd); | |
1265 | if (!dentry) { | |
1266 | struct dentry *new = d_alloc(base, name); | |
1267 | dentry = ERR_PTR(-ENOMEM); | |
1268 | if (!new) | |
1269 | goto out; | |
1270 | dentry = inode->i_op->lookup(inode, new, nd); | |
1271 | if (!dentry) | |
1272 | dentry = new; | |
1273 | else | |
1274 | dput(new); | |
1275 | } | |
1276 | out: | |
1277 | return dentry; | |
1278 | } | |
1279 | ||
057f6c01 JM |
1280 | /* |
1281 | * Restricted form of lookup. Doesn't follow links, single-component only, | |
1282 | * needs parent already locked. Doesn't follow mounts. | |
1283 | * SMP-safe. | |
1284 | */ | |
1285 | static inline struct dentry * __lookup_hash(struct qstr *name, struct dentry *base, struct nameidata *nd) | |
1286 | { | |
1287 | struct dentry *dentry; | |
1288 | struct inode *inode; | |
1289 | int err; | |
1290 | ||
1291 | inode = base->d_inode; | |
1292 | ||
1293 | err = permission(inode, MAY_EXEC, nd); | |
1294 | dentry = ERR_PTR(err); | |
1295 | if (err) | |
1296 | goto out; | |
1297 | ||
1298 | dentry = __lookup_hash_kern(name, base, nd); | |
1299 | out: | |
1300 | return dentry; | |
1301 | } | |
1302 | ||
a244e169 | 1303 | static struct dentry *lookup_hash(struct nameidata *nd) |
1da177e4 | 1304 | { |
49705b77 | 1305 | return __lookup_hash(&nd->last, nd->dentry, nd); |
1da177e4 LT |
1306 | } |
1307 | ||
1308 | /* SMP-safe */ | |
057f6c01 | 1309 | static inline int __lookup_one_len(const char *name, struct qstr *this, struct dentry *base, int len) |
1da177e4 LT |
1310 | { |
1311 | unsigned long hash; | |
1da177e4 LT |
1312 | unsigned int c; |
1313 | ||
057f6c01 JM |
1314 | this->name = name; |
1315 | this->len = len; | |
1da177e4 | 1316 | if (!len) |
057f6c01 | 1317 | return -EACCES; |
1da177e4 LT |
1318 | |
1319 | hash = init_name_hash(); | |
1320 | while (len--) { | |
1321 | c = *(const unsigned char *)name++; | |
1322 | if (c == '/' || c == '\0') | |
057f6c01 | 1323 | return -EACCES; |
1da177e4 LT |
1324 | hash = partial_name_hash(c, hash); |
1325 | } | |
057f6c01 JM |
1326 | this->hash = end_name_hash(hash); |
1327 | return 0; | |
1328 | } | |
1da177e4 | 1329 | |
057f6c01 JM |
1330 | struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) |
1331 | { | |
1332 | int err; | |
1333 | struct qstr this; | |
1334 | ||
1335 | err = __lookup_one_len(name, &this, base, len); | |
1336 | if (err) | |
1337 | return ERR_PTR(err); | |
49705b77 | 1338 | return __lookup_hash(&this, base, NULL); |
057f6c01 JM |
1339 | } |
1340 | ||
1341 | struct dentry *lookup_one_len_kern(const char *name, struct dentry *base, int len) | |
1342 | { | |
1343 | int err; | |
1344 | struct qstr this; | |
1345 | ||
1346 | err = __lookup_one_len(name, &this, base, len); | |
1347 | if (err) | |
1348 | return ERR_PTR(err); | |
1349 | return __lookup_hash_kern(&this, base, NULL); | |
1da177e4 LT |
1350 | } |
1351 | ||
5590ff0d UD |
1352 | int fastcall __user_walk_fd(int dfd, const char __user *name, unsigned flags, |
1353 | struct nameidata *nd) | |
1da177e4 LT |
1354 | { |
1355 | char *tmp = getname(name); | |
1356 | int err = PTR_ERR(tmp); | |
1357 | ||
1358 | if (!IS_ERR(tmp)) { | |
5590ff0d | 1359 | err = do_path_lookup(dfd, tmp, flags, nd); |
1da177e4 LT |
1360 | putname(tmp); |
1361 | } | |
1362 | return err; | |
1363 | } | |
1364 | ||
5590ff0d UD |
1365 | int fastcall __user_walk(const char __user *name, unsigned flags, struct nameidata *nd) |
1366 | { | |
1367 | return __user_walk_fd(AT_FDCWD, name, flags, nd); | |
1368 | } | |
1369 | ||
1da177e4 LT |
1370 | /* |
1371 | * It's inline, so penalty for filesystems that don't use sticky bit is | |
1372 | * minimal. | |
1373 | */ | |
1374 | static inline int check_sticky(struct inode *dir, struct inode *inode) | |
1375 | { | |
1376 | if (!(dir->i_mode & S_ISVTX)) | |
1377 | return 0; | |
1378 | if (inode->i_uid == current->fsuid) | |
1379 | return 0; | |
1380 | if (dir->i_uid == current->fsuid) | |
1381 | return 0; | |
1382 | return !capable(CAP_FOWNER); | |
1383 | } | |
1384 | ||
1385 | /* | |
1386 | * Check whether we can remove a link victim from directory dir, check | |
1387 | * whether the type of victim is right. | |
1388 | * 1. We can't do it if dir is read-only (done in permission()) | |
1389 | * 2. We should have write and exec permissions on dir | |
1390 | * 3. We can't remove anything from append-only dir | |
1391 | * 4. We can't do anything with immutable dir (done in permission()) | |
1392 | * 5. If the sticky bit on dir is set we should either | |
1393 | * a. be owner of dir, or | |
1394 | * b. be owner of victim, or | |
1395 | * c. have CAP_FOWNER capability | |
1396 | * 6. If the victim is append-only or immutable we can't do antyhing with | |
1397 | * links pointing to it. | |
1398 | * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. | |
1399 | * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. | |
1400 | * 9. We can't remove a root or mountpoint. | |
1401 | * 10. We don't allow removal of NFS sillyrenamed files; it's handled by | |
1402 | * nfs_async_unlink(). | |
1403 | */ | |
858119e1 | 1404 | static int may_delete(struct inode *dir,struct dentry *victim,int isdir) |
1da177e4 LT |
1405 | { |
1406 | int error; | |
1407 | ||
1408 | if (!victim->d_inode) | |
1409 | return -ENOENT; | |
1410 | ||
1411 | BUG_ON(victim->d_parent->d_inode != dir); | |
73d3ec5a | 1412 | audit_inode_child(victim->d_name.name, victim->d_inode, dir); |
1da177e4 LT |
1413 | |
1414 | error = permission(dir,MAY_WRITE | MAY_EXEC, NULL); | |
1415 | if (error) | |
1416 | return error; | |
1417 | if (IS_APPEND(dir)) | |
1418 | return -EPERM; | |
1419 | if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| | |
1420 | IS_IMMUTABLE(victim->d_inode)) | |
1421 | return -EPERM; | |
1422 | if (isdir) { | |
1423 | if (!S_ISDIR(victim->d_inode->i_mode)) | |
1424 | return -ENOTDIR; | |
1425 | if (IS_ROOT(victim)) | |
1426 | return -EBUSY; | |
1427 | } else if (S_ISDIR(victim->d_inode->i_mode)) | |
1428 | return -EISDIR; | |
1429 | if (IS_DEADDIR(dir)) | |
1430 | return -ENOENT; | |
1431 | if (victim->d_flags & DCACHE_NFSFS_RENAMED) | |
1432 | return -EBUSY; | |
1433 | return 0; | |
1434 | } | |
1435 | ||
1436 | /* Check whether we can create an object with dentry child in directory | |
1437 | * dir. | |
1438 | * 1. We can't do it if child already exists (open has special treatment for | |
1439 | * this case, but since we are inlined it's OK) | |
1440 | * 2. We can't do it if dir is read-only (done in permission()) | |
1441 | * 3. We should have write and exec permissions on dir | |
1442 | * 4. We can't do it if dir is immutable (done in permission()) | |
1443 | */ | |
1444 | static inline int may_create(struct inode *dir, struct dentry *child, | |
1445 | struct nameidata *nd) | |
1446 | { | |
1447 | if (child->d_inode) | |
1448 | return -EEXIST; | |
1449 | if (IS_DEADDIR(dir)) | |
1450 | return -ENOENT; | |
1451 | return permission(dir,MAY_WRITE | MAY_EXEC, nd); | |
1452 | } | |
1453 | ||
1454 | /* | |
1da177e4 LT |
1455 | * O_DIRECTORY translates into forcing a directory lookup. |
1456 | */ | |
1457 | static inline int lookup_flags(unsigned int f) | |
1458 | { | |
1459 | unsigned long retval = LOOKUP_FOLLOW; | |
1460 | ||
1461 | if (f & O_NOFOLLOW) | |
1462 | retval &= ~LOOKUP_FOLLOW; | |
1463 | ||
1da177e4 LT |
1464 | if (f & O_DIRECTORY) |
1465 | retval |= LOOKUP_DIRECTORY; | |
1466 | ||
1467 | return retval; | |
1468 | } | |
1469 | ||
1470 | /* | |
1471 | * p1 and p2 should be directories on the same fs. | |
1472 | */ | |
1473 | struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) | |
1474 | { | |
1475 | struct dentry *p; | |
1476 | ||
1477 | if (p1 == p2) { | |
f2eace23 | 1478 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
1da177e4 LT |
1479 | return NULL; |
1480 | } | |
1481 | ||
a11f3a05 | 1482 | mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
1da177e4 LT |
1483 | |
1484 | for (p = p1; p->d_parent != p; p = p->d_parent) { | |
1485 | if (p->d_parent == p2) { | |
f2eace23 IM |
1486 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); |
1487 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); | |
1da177e4 LT |
1488 | return p; |
1489 | } | |
1490 | } | |
1491 | ||
1492 | for (p = p2; p->d_parent != p; p = p->d_parent) { | |
1493 | if (p->d_parent == p1) { | |
f2eace23 IM |
1494 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
1495 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); | |
1da177e4 LT |
1496 | return p; |
1497 | } | |
1498 | } | |
1499 | ||
f2eace23 IM |
1500 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
1501 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); | |
1da177e4 LT |
1502 | return NULL; |
1503 | } | |
1504 | ||
1505 | void unlock_rename(struct dentry *p1, struct dentry *p2) | |
1506 | { | |
1b1dcc1b | 1507 | mutex_unlock(&p1->d_inode->i_mutex); |
1da177e4 | 1508 | if (p1 != p2) { |
1b1dcc1b | 1509 | mutex_unlock(&p2->d_inode->i_mutex); |
a11f3a05 | 1510 | mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
1da177e4 LT |
1511 | } |
1512 | } | |
1513 | ||
1514 | int vfs_create(struct inode *dir, struct dentry *dentry, int mode, | |
1515 | struct nameidata *nd) | |
1516 | { | |
1517 | int error = may_create(dir, dentry, nd); | |
1518 | ||
1519 | if (error) | |
1520 | return error; | |
1521 | ||
1522 | if (!dir->i_op || !dir->i_op->create) | |
1523 | return -EACCES; /* shouldn't it be ENOSYS? */ | |
1524 | mode &= S_IALLUGO; | |
1525 | mode |= S_IFREG; | |
1526 | error = security_inode_create(dir, dentry, mode); | |
1527 | if (error) | |
1528 | return error; | |
1529 | DQUOT_INIT(dir); | |
1530 | error = dir->i_op->create(dir, dentry, mode, nd); | |
a74574aa | 1531 | if (!error) |
f38aa942 | 1532 | fsnotify_create(dir, dentry); |
1da177e4 LT |
1533 | return error; |
1534 | } | |
1535 | ||
1536 | int may_open(struct nameidata *nd, int acc_mode, int flag) | |
1537 | { | |
1538 | struct dentry *dentry = nd->dentry; | |
1539 | struct inode *inode = dentry->d_inode; | |
1540 | int error; | |
1541 | ||
1542 | if (!inode) | |
1543 | return -ENOENT; | |
1544 | ||
1545 | if (S_ISLNK(inode->i_mode)) | |
1546 | return -ELOOP; | |
1547 | ||
1548 | if (S_ISDIR(inode->i_mode) && (flag & FMODE_WRITE)) | |
1549 | return -EISDIR; | |
1550 | ||
e4543edd | 1551 | error = vfs_permission(nd, acc_mode); |
1da177e4 LT |
1552 | if (error) |
1553 | return error; | |
1554 | ||
1555 | /* | |
1556 | * FIFO's, sockets and device files are special: they don't | |
1557 | * actually live on the filesystem itself, and as such you | |
1558 | * can write to them even if the filesystem is read-only. | |
1559 | */ | |
1560 | if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { | |
1561 | flag &= ~O_TRUNC; | |
1562 | } else if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) { | |
1563 | if (nd->mnt->mnt_flags & MNT_NODEV) | |
1564 | return -EACCES; | |
1565 | ||
1566 | flag &= ~O_TRUNC; | |
1567 | } else if (IS_RDONLY(inode) && (flag & FMODE_WRITE)) | |
1568 | return -EROFS; | |
1569 | /* | |
1570 | * An append-only file must be opened in append mode for writing. | |
1571 | */ | |
1572 | if (IS_APPEND(inode)) { | |
1573 | if ((flag & FMODE_WRITE) && !(flag & O_APPEND)) | |
1574 | return -EPERM; | |
1575 | if (flag & O_TRUNC) | |
1576 | return -EPERM; | |
1577 | } | |
1578 | ||
1579 | /* O_NOATIME can only be set by the owner or superuser */ | |
1580 | if (flag & O_NOATIME) | |
1581 | if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER)) | |
1582 | return -EPERM; | |
1583 | ||
1584 | /* | |
1585 | * Ensure there are no outstanding leases on the file. | |
1586 | */ | |
1587 | error = break_lease(inode, flag); | |
1588 | if (error) | |
1589 | return error; | |
1590 | ||
1591 | if (flag & O_TRUNC) { | |
1592 | error = get_write_access(inode); | |
1593 | if (error) | |
1594 | return error; | |
1595 | ||
1596 | /* | |
1597 | * Refuse to truncate files with mandatory locks held on them. | |
1598 | */ | |
1599 | error = locks_verify_locked(inode); | |
1600 | if (!error) { | |
1601 | DQUOT_INIT(inode); | |
1602 | ||
4a30131e | 1603 | error = do_truncate(dentry, 0, ATTR_MTIME|ATTR_CTIME, NULL); |
1da177e4 LT |
1604 | } |
1605 | put_write_access(inode); | |
1606 | if (error) | |
1607 | return error; | |
1608 | } else | |
1609 | if (flag & FMODE_WRITE) | |
1610 | DQUOT_INIT(inode); | |
1611 | ||
1612 | return 0; | |
1613 | } | |
1614 | ||
aab520e2 DH |
1615 | static int open_namei_create(struct nameidata *nd, struct path *path, |
1616 | int flag, int mode) | |
1617 | { | |
1618 | int error; | |
1619 | struct dentry *dir = nd->dentry; | |
1620 | ||
1621 | if (!IS_POSIXACL(dir->d_inode)) | |
1622 | mode &= ~current->fs->umask; | |
1623 | error = vfs_create(dir->d_inode, path->dentry, mode, nd); | |
1624 | mutex_unlock(&dir->d_inode->i_mutex); | |
1625 | dput(nd->dentry); | |
1626 | nd->dentry = path->dentry; | |
1627 | if (error) | |
1628 | return error; | |
1629 | /* Don't check for write permission, don't truncate */ | |
1630 | return may_open(nd, 0, flag & ~O_TRUNC); | |
1631 | } | |
1632 | ||
1da177e4 LT |
1633 | /* |
1634 | * open_namei() | |
1635 | * | |
1636 | * namei for open - this is in fact almost the whole open-routine. | |
1637 | * | |
1638 | * Note that the low bits of "flag" aren't the same as in the open | |
1639 | * system call - they are 00 - no permissions needed | |
1640 | * 01 - read permission needed | |
1641 | * 10 - write permission needed | |
1642 | * 11 - read/write permissions needed | |
1643 | * which is a lot more logical, and also allows the "no perm" needed | |
1644 | * for symlinks (where the permissions are checked later). | |
1645 | * SMP-safe | |
1646 | */ | |
5590ff0d UD |
1647 | int open_namei(int dfd, const char *pathname, int flag, |
1648 | int mode, struct nameidata *nd) | |
1da177e4 | 1649 | { |
834f2a4a | 1650 | int acc_mode, error; |
4e7506e4 | 1651 | struct path path; |
1da177e4 LT |
1652 | struct dentry *dir; |
1653 | int count = 0; | |
1654 | ||
1655 | acc_mode = ACC_MODE(flag); | |
1656 | ||
834f2a4a TM |
1657 | /* O_TRUNC implies we need access checks for write permissions */ |
1658 | if (flag & O_TRUNC) | |
1659 | acc_mode |= MAY_WRITE; | |
1660 | ||
1da177e4 LT |
1661 | /* Allow the LSM permission hook to distinguish append |
1662 | access from general write access. */ | |
1663 | if (flag & O_APPEND) | |
1664 | acc_mode |= MAY_APPEND; | |
1665 | ||
1da177e4 LT |
1666 | /* |
1667 | * The simplest case - just a plain lookup. | |
1668 | */ | |
1669 | if (!(flag & O_CREAT)) { | |
5590ff0d UD |
1670 | error = path_lookup_open(dfd, pathname, lookup_flags(flag), |
1671 | nd, flag); | |
1da177e4 LT |
1672 | if (error) |
1673 | return error; | |
1674 | goto ok; | |
1675 | } | |
1676 | ||
1677 | /* | |
1678 | * Create - we need to know the parent. | |
1679 | */ | |
5590ff0d | 1680 | error = path_lookup_create(dfd,pathname,LOOKUP_PARENT,nd,flag,mode); |
1da177e4 LT |
1681 | if (error) |
1682 | return error; | |
1683 | ||
1684 | /* | |
1685 | * We have the parent and last component. First of all, check | |
1686 | * that we are not asked to creat(2) an obvious directory - that | |
1687 | * will not do. | |
1688 | */ | |
1689 | error = -EISDIR; | |
1690 | if (nd->last_type != LAST_NORM || nd->last.name[nd->last.len]) | |
1691 | goto exit; | |
1692 | ||
1693 | dir = nd->dentry; | |
1694 | nd->flags &= ~LOOKUP_PARENT; | |
1b1dcc1b | 1695 | mutex_lock(&dir->d_inode->i_mutex); |
49705b77 | 1696 | path.dentry = lookup_hash(nd); |
d73ffe16 | 1697 | path.mnt = nd->mnt; |
1da177e4 LT |
1698 | |
1699 | do_last: | |
4e7506e4 AV |
1700 | error = PTR_ERR(path.dentry); |
1701 | if (IS_ERR(path.dentry)) { | |
1b1dcc1b | 1702 | mutex_unlock(&dir->d_inode->i_mutex); |
1da177e4 LT |
1703 | goto exit; |
1704 | } | |
1705 | ||
4af4c52f OD |
1706 | if (IS_ERR(nd->intent.open.file)) { |
1707 | mutex_unlock(&dir->d_inode->i_mutex); | |
1708 | error = PTR_ERR(nd->intent.open.file); | |
1709 | goto exit_dput; | |
1710 | } | |
1711 | ||
1da177e4 | 1712 | /* Negative dentry, just create the file */ |
4e7506e4 | 1713 | if (!path.dentry->d_inode) { |
aab520e2 | 1714 | error = open_namei_create(nd, &path, flag, mode); |
1da177e4 LT |
1715 | if (error) |
1716 | goto exit; | |
aab520e2 | 1717 | return 0; |
1da177e4 LT |
1718 | } |
1719 | ||
1720 | /* | |
1721 | * It already exists. | |
1722 | */ | |
1b1dcc1b | 1723 | mutex_unlock(&dir->d_inode->i_mutex); |
3e2efce0 | 1724 | audit_inode_update(path.dentry->d_inode); |
1da177e4 LT |
1725 | |
1726 | error = -EEXIST; | |
1727 | if (flag & O_EXCL) | |
1728 | goto exit_dput; | |
1729 | ||
e13b210f | 1730 | if (__follow_mount(&path)) { |
1da177e4 | 1731 | error = -ELOOP; |
ba7a4c1a AV |
1732 | if (flag & O_NOFOLLOW) |
1733 | goto exit_dput; | |
1da177e4 | 1734 | } |
3e2efce0 | 1735 | |
1da177e4 | 1736 | error = -ENOENT; |
4e7506e4 | 1737 | if (!path.dentry->d_inode) |
1da177e4 | 1738 | goto exit_dput; |
4e7506e4 | 1739 | if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link) |
1da177e4 LT |
1740 | goto do_link; |
1741 | ||
09dd17d3 | 1742 | path_to_nameidata(&path, nd); |
1da177e4 | 1743 | error = -EISDIR; |
4e7506e4 | 1744 | if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode)) |
1da177e4 LT |
1745 | goto exit; |
1746 | ok: | |
1747 | error = may_open(nd, acc_mode, flag); | |
1748 | if (error) | |
1749 | goto exit; | |
1750 | return 0; | |
1751 | ||
1752 | exit_dput: | |
09dd17d3 | 1753 | dput_path(&path, nd); |
1da177e4 | 1754 | exit: |
834f2a4a TM |
1755 | if (!IS_ERR(nd->intent.open.file)) |
1756 | release_open_intent(nd); | |
1da177e4 LT |
1757 | path_release(nd); |
1758 | return error; | |
1759 | ||
1760 | do_link: | |
1761 | error = -ELOOP; | |
1762 | if (flag & O_NOFOLLOW) | |
1763 | goto exit_dput; | |
1764 | /* | |
1765 | * This is subtle. Instead of calling do_follow_link() we do the | |
1766 | * thing by hands. The reason is that this way we have zero link_count | |
1767 | * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT. | |
1768 | * After that we have the parent and last component, i.e. | |
1769 | * we are in the same situation as after the first path_walk(). | |
1770 | * Well, almost - if the last component is normal we get its copy | |
1771 | * stored in nd->last.name and we will have to putname() it when we | |
1772 | * are done. Procfs-like symlinks just set LAST_BIND. | |
1773 | */ | |
1774 | nd->flags |= LOOKUP_PARENT; | |
4e7506e4 | 1775 | error = security_inode_follow_link(path.dentry, nd); |
1da177e4 LT |
1776 | if (error) |
1777 | goto exit_dput; | |
cd4e91d3 | 1778 | error = __do_follow_link(&path, nd); |
de459215 KK |
1779 | if (error) { |
1780 | /* Does someone understand code flow here? Or it is only | |
1781 | * me so stupid? Anathema to whoever designed this non-sense | |
1782 | * with "intent.open". | |
1783 | */ | |
1784 | release_open_intent(nd); | |
1da177e4 | 1785 | return error; |
de459215 | 1786 | } |
1da177e4 | 1787 | nd->flags &= ~LOOKUP_PARENT; |
d671d5e5 | 1788 | if (nd->last_type == LAST_BIND) |
1da177e4 | 1789 | goto ok; |
1da177e4 LT |
1790 | error = -EISDIR; |
1791 | if (nd->last_type != LAST_NORM) | |
1792 | goto exit; | |
1793 | if (nd->last.name[nd->last.len]) { | |
82984114 | 1794 | __putname(nd->last.name); |
1da177e4 LT |
1795 | goto exit; |
1796 | } | |
1797 | error = -ELOOP; | |
1798 | if (count++==32) { | |
82984114 | 1799 | __putname(nd->last.name); |
1da177e4 LT |
1800 | goto exit; |
1801 | } | |
1802 | dir = nd->dentry; | |
1b1dcc1b | 1803 | mutex_lock(&dir->d_inode->i_mutex); |
49705b77 | 1804 | path.dentry = lookup_hash(nd); |
d671d5e5 | 1805 | path.mnt = nd->mnt; |
82984114 | 1806 | __putname(nd->last.name); |
1da177e4 LT |
1807 | goto do_last; |
1808 | } | |
1809 | ||
1810 | /** | |
1811 | * lookup_create - lookup a dentry, creating it if it doesn't exist | |
1812 | * @nd: nameidata info | |
1813 | * @is_dir: directory flag | |
1814 | * | |
1815 | * Simple function to lookup and return a dentry and create it | |
1816 | * if it doesn't exist. Is SMP-safe. | |
c663e5d8 | 1817 | * |
1b1dcc1b | 1818 | * Returns with nd->dentry->d_inode->i_mutex locked. |
1da177e4 LT |
1819 | */ |
1820 | struct dentry *lookup_create(struct nameidata *nd, int is_dir) | |
1821 | { | |
c663e5d8 | 1822 | struct dentry *dentry = ERR_PTR(-EEXIST); |
1da177e4 | 1823 | |
f2eace23 | 1824 | mutex_lock_nested(&nd->dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
c663e5d8 CH |
1825 | /* |
1826 | * Yucky last component or no last component at all? | |
1827 | * (foo/., foo/.., /////) | |
1828 | */ | |
1da177e4 LT |
1829 | if (nd->last_type != LAST_NORM) |
1830 | goto fail; | |
1831 | nd->flags &= ~LOOKUP_PARENT; | |
a634904a AM |
1832 | nd->flags |= LOOKUP_CREATE; |
1833 | nd->intent.open.flags = O_EXCL; | |
c663e5d8 CH |
1834 | |
1835 | /* | |
1836 | * Do the final lookup. | |
1837 | */ | |
49705b77 | 1838 | dentry = lookup_hash(nd); |
1da177e4 LT |
1839 | if (IS_ERR(dentry)) |
1840 | goto fail; | |
c663e5d8 CH |
1841 | |
1842 | /* | |
1843 | * Special case - lookup gave negative, but... we had foo/bar/ | |
1844 | * From the vfs_mknod() POV we just have a negative dentry - | |
1845 | * all is fine. Let's be bastards - you had / on the end, you've | |
1846 | * been asking for (non-existent) directory. -ENOENT for you. | |
1847 | */ | |
1da177e4 LT |
1848 | if (!is_dir && nd->last.name[nd->last.len] && !dentry->d_inode) |
1849 | goto enoent; | |
1850 | return dentry; | |
1851 | enoent: | |
1852 | dput(dentry); | |
1853 | dentry = ERR_PTR(-ENOENT); | |
1854 | fail: | |
1855 | return dentry; | |
1856 | } | |
f81a0bff | 1857 | EXPORT_SYMBOL_GPL(lookup_create); |
1da177e4 LT |
1858 | |
1859 | int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1860 | { | |
1861 | int error = may_create(dir, dentry, NULL); | |
1862 | ||
1863 | if (error) | |
1864 | return error; | |
1865 | ||
1866 | if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) | |
1867 | return -EPERM; | |
1868 | ||
1869 | if (!dir->i_op || !dir->i_op->mknod) | |
1870 | return -EPERM; | |
1871 | ||
1872 | error = security_inode_mknod(dir, dentry, mode, dev); | |
1873 | if (error) | |
1874 | return error; | |
1875 | ||
1876 | DQUOT_INIT(dir); | |
1877 | error = dir->i_op->mknod(dir, dentry, mode, dev); | |
a74574aa | 1878 | if (!error) |
f38aa942 | 1879 | fsnotify_create(dir, dentry); |
1da177e4 LT |
1880 | return error; |
1881 | } | |
1882 | ||
5590ff0d UD |
1883 | asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, |
1884 | unsigned dev) | |
1da177e4 LT |
1885 | { |
1886 | int error = 0; | |
1887 | char * tmp; | |
1888 | struct dentry * dentry; | |
1889 | struct nameidata nd; | |
1890 | ||
1891 | if (S_ISDIR(mode)) | |
1892 | return -EPERM; | |
1893 | tmp = getname(filename); | |
1894 | if (IS_ERR(tmp)) | |
1895 | return PTR_ERR(tmp); | |
1896 | ||
5590ff0d | 1897 | error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd); |
1da177e4 LT |
1898 | if (error) |
1899 | goto out; | |
1900 | dentry = lookup_create(&nd, 0); | |
1901 | error = PTR_ERR(dentry); | |
1902 | ||
1903 | if (!IS_POSIXACL(nd.dentry->d_inode)) | |
1904 | mode &= ~current->fs->umask; | |
1905 | if (!IS_ERR(dentry)) { | |
1906 | switch (mode & S_IFMT) { | |
1907 | case 0: case S_IFREG: | |
1908 | error = vfs_create(nd.dentry->d_inode,dentry,mode,&nd); | |
1909 | break; | |
1910 | case S_IFCHR: case S_IFBLK: | |
1911 | error = vfs_mknod(nd.dentry->d_inode,dentry,mode, | |
1912 | new_decode_dev(dev)); | |
1913 | break; | |
1914 | case S_IFIFO: case S_IFSOCK: | |
1915 | error = vfs_mknod(nd.dentry->d_inode,dentry,mode,0); | |
1916 | break; | |
1917 | case S_IFDIR: | |
1918 | error = -EPERM; | |
1919 | break; | |
1920 | default: | |
1921 | error = -EINVAL; | |
1922 | } | |
1923 | dput(dentry); | |
1924 | } | |
1b1dcc1b | 1925 | mutex_unlock(&nd.dentry->d_inode->i_mutex); |
1da177e4 LT |
1926 | path_release(&nd); |
1927 | out: | |
1928 | putname(tmp); | |
1929 | ||
1930 | return error; | |
1931 | } | |
1932 | ||
5590ff0d UD |
1933 | asmlinkage long sys_mknod(const char __user *filename, int mode, unsigned dev) |
1934 | { | |
1935 | return sys_mknodat(AT_FDCWD, filename, mode, dev); | |
1936 | } | |
1937 | ||
1da177e4 LT |
1938 | int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
1939 | { | |
1940 | int error = may_create(dir, dentry, NULL); | |
1941 | ||
1942 | if (error) | |
1943 | return error; | |
1944 | ||
1945 | if (!dir->i_op || !dir->i_op->mkdir) | |
1946 | return -EPERM; | |
1947 | ||
1948 | mode &= (S_IRWXUGO|S_ISVTX); | |
1949 | error = security_inode_mkdir(dir, dentry, mode); | |
1950 | if (error) | |
1951 | return error; | |
1952 | ||
1953 | DQUOT_INIT(dir); | |
1954 | error = dir->i_op->mkdir(dir, dentry, mode); | |
a74574aa | 1955 | if (!error) |
f38aa942 | 1956 | fsnotify_mkdir(dir, dentry); |
1da177e4 LT |
1957 | return error; |
1958 | } | |
1959 | ||
5590ff0d | 1960 | asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) |
1da177e4 LT |
1961 | { |
1962 | int error = 0; | |
1963 | char * tmp; | |
6902d925 DH |
1964 | struct dentry *dentry; |
1965 | struct nameidata nd; | |
1da177e4 LT |
1966 | |
1967 | tmp = getname(pathname); | |
1968 | error = PTR_ERR(tmp); | |
6902d925 DH |
1969 | if (IS_ERR(tmp)) |
1970 | goto out_err; | |
1da177e4 | 1971 | |
6902d925 DH |
1972 | error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd); |
1973 | if (error) | |
1974 | goto out; | |
1975 | dentry = lookup_create(&nd, 1); | |
1976 | error = PTR_ERR(dentry); | |
1977 | if (IS_ERR(dentry)) | |
1978 | goto out_unlock; | |
1da177e4 | 1979 | |
6902d925 DH |
1980 | if (!IS_POSIXACL(nd.dentry->d_inode)) |
1981 | mode &= ~current->fs->umask; | |
1982 | error = vfs_mkdir(nd.dentry->d_inode, dentry, mode); | |
1983 | dput(dentry); | |
1984 | out_unlock: | |
1985 | mutex_unlock(&nd.dentry->d_inode->i_mutex); | |
1986 | path_release(&nd); | |
1987 | out: | |
1988 | putname(tmp); | |
1989 | out_err: | |
1da177e4 LT |
1990 | return error; |
1991 | } | |
1992 | ||
5590ff0d UD |
1993 | asmlinkage long sys_mkdir(const char __user *pathname, int mode) |
1994 | { | |
1995 | return sys_mkdirat(AT_FDCWD, pathname, mode); | |
1996 | } | |
1997 | ||
1da177e4 LT |
1998 | /* |
1999 | * We try to drop the dentry early: we should have | |
2000 | * a usage count of 2 if we're the only user of this | |
2001 | * dentry, and if that is true (possibly after pruning | |
2002 | * the dcache), then we drop the dentry now. | |
2003 | * | |
2004 | * A low-level filesystem can, if it choses, legally | |
2005 | * do a | |
2006 | * | |
2007 | * if (!d_unhashed(dentry)) | |
2008 | * return -EBUSY; | |
2009 | * | |
2010 | * if it cannot handle the case of removing a directory | |
2011 | * that is still in use by something else.. | |
2012 | */ | |
2013 | void dentry_unhash(struct dentry *dentry) | |
2014 | { | |
2015 | dget(dentry); | |
dc168427 | 2016 | shrink_dcache_parent(dentry); |
1da177e4 LT |
2017 | spin_lock(&dcache_lock); |
2018 | spin_lock(&dentry->d_lock); | |
2019 | if (atomic_read(&dentry->d_count) == 2) | |
2020 | __d_drop(dentry); | |
2021 | spin_unlock(&dentry->d_lock); | |
2022 | spin_unlock(&dcache_lock); | |
2023 | } | |
2024 | ||
2025 | int vfs_rmdir(struct inode *dir, struct dentry *dentry) | |
2026 | { | |
2027 | int error = may_delete(dir, dentry, 1); | |
2028 | ||
2029 | if (error) | |
2030 | return error; | |
2031 | ||
2032 | if (!dir->i_op || !dir->i_op->rmdir) | |
2033 | return -EPERM; | |
2034 | ||
2035 | DQUOT_INIT(dir); | |
2036 | ||
1b1dcc1b | 2037 | mutex_lock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
2038 | dentry_unhash(dentry); |
2039 | if (d_mountpoint(dentry)) | |
2040 | error = -EBUSY; | |
2041 | else { | |
2042 | error = security_inode_rmdir(dir, dentry); | |
2043 | if (!error) { | |
2044 | error = dir->i_op->rmdir(dir, dentry); | |
2045 | if (!error) | |
2046 | dentry->d_inode->i_flags |= S_DEAD; | |
2047 | } | |
2048 | } | |
1b1dcc1b | 2049 | mutex_unlock(&dentry->d_inode->i_mutex); |
1da177e4 | 2050 | if (!error) { |
1da177e4 LT |
2051 | d_delete(dentry); |
2052 | } | |
2053 | dput(dentry); | |
2054 | ||
2055 | return error; | |
2056 | } | |
2057 | ||
5590ff0d | 2058 | static long do_rmdir(int dfd, const char __user *pathname) |
1da177e4 LT |
2059 | { |
2060 | int error = 0; | |
2061 | char * name; | |
2062 | struct dentry *dentry; | |
2063 | struct nameidata nd; | |
2064 | ||
2065 | name = getname(pathname); | |
2066 | if(IS_ERR(name)) | |
2067 | return PTR_ERR(name); | |
2068 | ||
5590ff0d | 2069 | error = do_path_lookup(dfd, name, LOOKUP_PARENT, &nd); |
1da177e4 LT |
2070 | if (error) |
2071 | goto exit; | |
2072 | ||
2073 | switch(nd.last_type) { | |
2074 | case LAST_DOTDOT: | |
2075 | error = -ENOTEMPTY; | |
2076 | goto exit1; | |
2077 | case LAST_DOT: | |
2078 | error = -EINVAL; | |
2079 | goto exit1; | |
2080 | case LAST_ROOT: | |
2081 | error = -EBUSY; | |
2082 | goto exit1; | |
2083 | } | |
f2eace23 | 2084 | mutex_lock_nested(&nd.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
49705b77 | 2085 | dentry = lookup_hash(&nd); |
1da177e4 | 2086 | error = PTR_ERR(dentry); |
6902d925 DH |
2087 | if (IS_ERR(dentry)) |
2088 | goto exit2; | |
2089 | error = vfs_rmdir(nd.dentry->d_inode, dentry); | |
2090 | dput(dentry); | |
2091 | exit2: | |
1b1dcc1b | 2092 | mutex_unlock(&nd.dentry->d_inode->i_mutex); |
1da177e4 LT |
2093 | exit1: |
2094 | path_release(&nd); | |
2095 | exit: | |
2096 | putname(name); | |
2097 | return error; | |
2098 | } | |
2099 | ||
5590ff0d UD |
2100 | asmlinkage long sys_rmdir(const char __user *pathname) |
2101 | { | |
2102 | return do_rmdir(AT_FDCWD, pathname); | |
2103 | } | |
2104 | ||
1da177e4 LT |
2105 | int vfs_unlink(struct inode *dir, struct dentry *dentry) |
2106 | { | |
2107 | int error = may_delete(dir, dentry, 0); | |
2108 | ||
2109 | if (error) | |
2110 | return error; | |
2111 | ||
2112 | if (!dir->i_op || !dir->i_op->unlink) | |
2113 | return -EPERM; | |
2114 | ||
2115 | DQUOT_INIT(dir); | |
2116 | ||
1b1dcc1b | 2117 | mutex_lock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
2118 | if (d_mountpoint(dentry)) |
2119 | error = -EBUSY; | |
2120 | else { | |
2121 | error = security_inode_unlink(dir, dentry); | |
2122 | if (!error) | |
2123 | error = dir->i_op->unlink(dir, dentry); | |
2124 | } | |
1b1dcc1b | 2125 | mutex_unlock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
2126 | |
2127 | /* We don't d_delete() NFS sillyrenamed files--they still exist. */ | |
2128 | if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { | |
e234f35c | 2129 | d_delete(dentry); |
1da177e4 | 2130 | } |
0eeca283 | 2131 | |
1da177e4 LT |
2132 | return error; |
2133 | } | |
2134 | ||
2135 | /* | |
2136 | * Make sure that the actual truncation of the file will occur outside its | |
1b1dcc1b | 2137 | * directory's i_mutex. Truncate can take a long time if there is a lot of |
1da177e4 LT |
2138 | * writeout happening, and we don't want to prevent access to the directory |
2139 | * while waiting on the I/O. | |
2140 | */ | |
5590ff0d | 2141 | static long do_unlinkat(int dfd, const char __user *pathname) |
1da177e4 LT |
2142 | { |
2143 | int error = 0; | |
2144 | char * name; | |
2145 | struct dentry *dentry; | |
2146 | struct nameidata nd; | |
2147 | struct inode *inode = NULL; | |
2148 | ||
2149 | name = getname(pathname); | |
2150 | if(IS_ERR(name)) | |
2151 | return PTR_ERR(name); | |
2152 | ||
5590ff0d | 2153 | error = do_path_lookup(dfd, name, LOOKUP_PARENT, &nd); |
1da177e4 LT |
2154 | if (error) |
2155 | goto exit; | |
2156 | error = -EISDIR; | |
2157 | if (nd.last_type != LAST_NORM) | |
2158 | goto exit1; | |
f2eace23 | 2159 | mutex_lock_nested(&nd.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
49705b77 | 2160 | dentry = lookup_hash(&nd); |
1da177e4 LT |
2161 | error = PTR_ERR(dentry); |
2162 | if (!IS_ERR(dentry)) { | |
2163 | /* Why not before? Because we want correct error value */ | |
2164 | if (nd.last.name[nd.last.len]) | |
2165 | goto slashes; | |
2166 | inode = dentry->d_inode; | |
2167 | if (inode) | |
2168 | atomic_inc(&inode->i_count); | |
2169 | error = vfs_unlink(nd.dentry->d_inode, dentry); | |
2170 | exit2: | |
2171 | dput(dentry); | |
2172 | } | |
1b1dcc1b | 2173 | mutex_unlock(&nd.dentry->d_inode->i_mutex); |
1da177e4 LT |
2174 | if (inode) |
2175 | iput(inode); /* truncate the inode here */ | |
2176 | exit1: | |
2177 | path_release(&nd); | |
2178 | exit: | |
2179 | putname(name); | |
2180 | return error; | |
2181 | ||
2182 | slashes: | |
2183 | error = !dentry->d_inode ? -ENOENT : | |
2184 | S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; | |
2185 | goto exit2; | |
2186 | } | |
2187 | ||
5590ff0d UD |
2188 | asmlinkage long sys_unlinkat(int dfd, const char __user *pathname, int flag) |
2189 | { | |
2190 | if ((flag & ~AT_REMOVEDIR) != 0) | |
2191 | return -EINVAL; | |
2192 | ||
2193 | if (flag & AT_REMOVEDIR) | |
2194 | return do_rmdir(dfd, pathname); | |
2195 | ||
2196 | return do_unlinkat(dfd, pathname); | |
2197 | } | |
2198 | ||
2199 | asmlinkage long sys_unlink(const char __user *pathname) | |
2200 | { | |
2201 | return do_unlinkat(AT_FDCWD, pathname); | |
2202 | } | |
2203 | ||
1da177e4 LT |
2204 | int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname, int mode) |
2205 | { | |
2206 | int error = may_create(dir, dentry, NULL); | |
2207 | ||
2208 | if (error) | |
2209 | return error; | |
2210 | ||
2211 | if (!dir->i_op || !dir->i_op->symlink) | |
2212 | return -EPERM; | |
2213 | ||
2214 | error = security_inode_symlink(dir, dentry, oldname); | |
2215 | if (error) | |
2216 | return error; | |
2217 | ||
2218 | DQUOT_INIT(dir); | |
2219 | error = dir->i_op->symlink(dir, dentry, oldname); | |
a74574aa | 2220 | if (!error) |
f38aa942 | 2221 | fsnotify_create(dir, dentry); |
1da177e4 LT |
2222 | return error; |
2223 | } | |
2224 | ||
5590ff0d UD |
2225 | asmlinkage long sys_symlinkat(const char __user *oldname, |
2226 | int newdfd, const char __user *newname) | |
1da177e4 LT |
2227 | { |
2228 | int error = 0; | |
2229 | char * from; | |
2230 | char * to; | |
6902d925 DH |
2231 | struct dentry *dentry; |
2232 | struct nameidata nd; | |
1da177e4 LT |
2233 | |
2234 | from = getname(oldname); | |
2235 | if(IS_ERR(from)) | |
2236 | return PTR_ERR(from); | |
2237 | to = getname(newname); | |
2238 | error = PTR_ERR(to); | |
6902d925 DH |
2239 | if (IS_ERR(to)) |
2240 | goto out_putname; | |
1da177e4 | 2241 | |
6902d925 DH |
2242 | error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd); |
2243 | if (error) | |
2244 | goto out; | |
2245 | dentry = lookup_create(&nd, 0); | |
2246 | error = PTR_ERR(dentry); | |
2247 | if (IS_ERR(dentry)) | |
2248 | goto out_unlock; | |
2249 | ||
2250 | error = vfs_symlink(nd.dentry->d_inode, dentry, from, S_IALLUGO); | |
2251 | dput(dentry); | |
2252 | out_unlock: | |
2253 | mutex_unlock(&nd.dentry->d_inode->i_mutex); | |
2254 | path_release(&nd); | |
1da177e4 | 2255 | out: |
6902d925 DH |
2256 | putname(to); |
2257 | out_putname: | |
1da177e4 LT |
2258 | putname(from); |
2259 | return error; | |
2260 | } | |
2261 | ||
5590ff0d UD |
2262 | asmlinkage long sys_symlink(const char __user *oldname, const char __user *newname) |
2263 | { | |
2264 | return sys_symlinkat(oldname, AT_FDCWD, newname); | |
2265 | } | |
2266 | ||
1da177e4 LT |
2267 | int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) |
2268 | { | |
2269 | struct inode *inode = old_dentry->d_inode; | |
2270 | int error; | |
2271 | ||
2272 | if (!inode) | |
2273 | return -ENOENT; | |
2274 | ||
2275 | error = may_create(dir, new_dentry, NULL); | |
2276 | if (error) | |
2277 | return error; | |
2278 | ||
2279 | if (dir->i_sb != inode->i_sb) | |
2280 | return -EXDEV; | |
2281 | ||
2282 | /* | |
2283 | * A link to an append-only or immutable file cannot be created. | |
2284 | */ | |
2285 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) | |
2286 | return -EPERM; | |
2287 | if (!dir->i_op || !dir->i_op->link) | |
2288 | return -EPERM; | |
2289 | if (S_ISDIR(old_dentry->d_inode->i_mode)) | |
2290 | return -EPERM; | |
2291 | ||
2292 | error = security_inode_link(old_dentry, dir, new_dentry); | |
2293 | if (error) | |
2294 | return error; | |
2295 | ||
1b1dcc1b | 2296 | mutex_lock(&old_dentry->d_inode->i_mutex); |
1da177e4 LT |
2297 | DQUOT_INIT(dir); |
2298 | error = dir->i_op->link(old_dentry, dir, new_dentry); | |
1b1dcc1b | 2299 | mutex_unlock(&old_dentry->d_inode->i_mutex); |
e31e14ec | 2300 | if (!error) |
f38aa942 | 2301 | fsnotify_create(dir, new_dentry); |
1da177e4 LT |
2302 | return error; |
2303 | } | |
2304 | ||
2305 | /* | |
2306 | * Hardlinks are often used in delicate situations. We avoid | |
2307 | * security-related surprises by not following symlinks on the | |
2308 | * newname. --KAB | |
2309 | * | |
2310 | * We don't follow them on the oldname either to be compatible | |
2311 | * with linux 2.0, and to avoid hard-linking to directories | |
2312 | * and other special files. --ADM | |
2313 | */ | |
5590ff0d | 2314 | asmlinkage long sys_linkat(int olddfd, const char __user *oldname, |
c04030e1 UD |
2315 | int newdfd, const char __user *newname, |
2316 | int flags) | |
1da177e4 LT |
2317 | { |
2318 | struct dentry *new_dentry; | |
2319 | struct nameidata nd, old_nd; | |
2320 | int error; | |
2321 | char * to; | |
2322 | ||
45c9b11a | 2323 | if ((flags & ~AT_SYMLINK_FOLLOW) != 0) |
c04030e1 UD |
2324 | return -EINVAL; |
2325 | ||
1da177e4 LT |
2326 | to = getname(newname); |
2327 | if (IS_ERR(to)) | |
2328 | return PTR_ERR(to); | |
2329 | ||
45c9b11a UD |
2330 | error = __user_walk_fd(olddfd, oldname, |
2331 | flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, | |
2332 | &old_nd); | |
1da177e4 LT |
2333 | if (error) |
2334 | goto exit; | |
5590ff0d | 2335 | error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd); |
1da177e4 LT |
2336 | if (error) |
2337 | goto out; | |
2338 | error = -EXDEV; | |
2339 | if (old_nd.mnt != nd.mnt) | |
2340 | goto out_release; | |
2341 | new_dentry = lookup_create(&nd, 0); | |
2342 | error = PTR_ERR(new_dentry); | |
6902d925 DH |
2343 | if (IS_ERR(new_dentry)) |
2344 | goto out_unlock; | |
2345 | error = vfs_link(old_nd.dentry, nd.dentry->d_inode, new_dentry); | |
2346 | dput(new_dentry); | |
2347 | out_unlock: | |
1b1dcc1b | 2348 | mutex_unlock(&nd.dentry->d_inode->i_mutex); |
1da177e4 LT |
2349 | out_release: |
2350 | path_release(&nd); | |
2351 | out: | |
2352 | path_release(&old_nd); | |
2353 | exit: | |
2354 | putname(to); | |
2355 | ||
2356 | return error; | |
2357 | } | |
2358 | ||
5590ff0d UD |
2359 | asmlinkage long sys_link(const char __user *oldname, const char __user *newname) |
2360 | { | |
c04030e1 | 2361 | return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); |
5590ff0d UD |
2362 | } |
2363 | ||
1da177e4 LT |
2364 | /* |
2365 | * The worst of all namespace operations - renaming directory. "Perverted" | |
2366 | * doesn't even start to describe it. Somebody in UCB had a heck of a trip... | |
2367 | * Problems: | |
2368 | * a) we can get into loop creation. Check is done in is_subdir(). | |
2369 | * b) race potential - two innocent renames can create a loop together. | |
2370 | * That's where 4.4 screws up. Current fix: serialization on | |
a11f3a05 | 2371 | * sb->s_vfs_rename_mutex. We might be more accurate, but that's another |
1da177e4 LT |
2372 | * story. |
2373 | * c) we have to lock _three_ objects - parents and victim (if it exists). | |
1b1dcc1b | 2374 | * And that - after we got ->i_mutex on parents (until then we don't know |
1da177e4 LT |
2375 | * whether the target exists). Solution: try to be smart with locking |
2376 | * order for inodes. We rely on the fact that tree topology may change | |
a11f3a05 | 2377 | * only under ->s_vfs_rename_mutex _and_ that parent of the object we |
1da177e4 LT |
2378 | * move will be locked. Thus we can rank directories by the tree |
2379 | * (ancestors first) and rank all non-directories after them. | |
2380 | * That works since everybody except rename does "lock parent, lookup, | |
a11f3a05 | 2381 | * lock child" and rename is under ->s_vfs_rename_mutex. |
1da177e4 LT |
2382 | * HOWEVER, it relies on the assumption that any object with ->lookup() |
2383 | * has no more than 1 dentry. If "hybrid" objects will ever appear, | |
2384 | * we'd better make sure that there's no link(2) for them. | |
2385 | * d) some filesystems don't support opened-but-unlinked directories, | |
2386 | * either because of layout or because they are not ready to deal with | |
2387 | * all cases correctly. The latter will be fixed (taking this sort of | |
2388 | * stuff into VFS), but the former is not going away. Solution: the same | |
2389 | * trick as in rmdir(). | |
2390 | * e) conversion from fhandle to dentry may come in the wrong moment - when | |
1b1dcc1b | 2391 | * we are removing the target. Solution: we will have to grab ->i_mutex |
1da177e4 | 2392 | * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on |
1b1dcc1b | 2393 | * ->i_mutex on parents, which works but leads to some truely excessive |
1da177e4 LT |
2394 | * locking]. |
2395 | */ | |
75c96f85 AB |
2396 | static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, |
2397 | struct inode *new_dir, struct dentry *new_dentry) | |
1da177e4 LT |
2398 | { |
2399 | int error = 0; | |
2400 | struct inode *target; | |
2401 | ||
2402 | /* | |
2403 | * If we are going to change the parent - check write permissions, | |
2404 | * we'll need to flip '..'. | |
2405 | */ | |
2406 | if (new_dir != old_dir) { | |
2407 | error = permission(old_dentry->d_inode, MAY_WRITE, NULL); | |
2408 | if (error) | |
2409 | return error; | |
2410 | } | |
2411 | ||
2412 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); | |
2413 | if (error) | |
2414 | return error; | |
2415 | ||
2416 | target = new_dentry->d_inode; | |
2417 | if (target) { | |
1b1dcc1b | 2418 | mutex_lock(&target->i_mutex); |
1da177e4 LT |
2419 | dentry_unhash(new_dentry); |
2420 | } | |
2421 | if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) | |
2422 | error = -EBUSY; | |
2423 | else | |
2424 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); | |
2425 | if (target) { | |
2426 | if (!error) | |
2427 | target->i_flags |= S_DEAD; | |
1b1dcc1b | 2428 | mutex_unlock(&target->i_mutex); |
1da177e4 LT |
2429 | if (d_unhashed(new_dentry)) |
2430 | d_rehash(new_dentry); | |
2431 | dput(new_dentry); | |
2432 | } | |
e31e14ec | 2433 | if (!error) |
349457cc MF |
2434 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
2435 | d_move(old_dentry,new_dentry); | |
1da177e4 LT |
2436 | return error; |
2437 | } | |
2438 | ||
75c96f85 AB |
2439 | static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, |
2440 | struct inode *new_dir, struct dentry *new_dentry) | |
1da177e4 LT |
2441 | { |
2442 | struct inode *target; | |
2443 | int error; | |
2444 | ||
2445 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); | |
2446 | if (error) | |
2447 | return error; | |
2448 | ||
2449 | dget(new_dentry); | |
2450 | target = new_dentry->d_inode; | |
2451 | if (target) | |
1b1dcc1b | 2452 | mutex_lock(&target->i_mutex); |
1da177e4 LT |
2453 | if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) |
2454 | error = -EBUSY; | |
2455 | else | |
2456 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); | |
2457 | if (!error) { | |
349457cc | 2458 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
1da177e4 | 2459 | d_move(old_dentry, new_dentry); |
1da177e4 LT |
2460 | } |
2461 | if (target) | |
1b1dcc1b | 2462 | mutex_unlock(&target->i_mutex); |
1da177e4 LT |
2463 | dput(new_dentry); |
2464 | return error; | |
2465 | } | |
2466 | ||
2467 | int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, | |
2468 | struct inode *new_dir, struct dentry *new_dentry) | |
2469 | { | |
2470 | int error; | |
2471 | int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); | |
0eeca283 | 2472 | const char *old_name; |
1da177e4 LT |
2473 | |
2474 | if (old_dentry->d_inode == new_dentry->d_inode) | |
2475 | return 0; | |
2476 | ||
2477 | error = may_delete(old_dir, old_dentry, is_dir); | |
2478 | if (error) | |
2479 | return error; | |
2480 | ||
2481 | if (!new_dentry->d_inode) | |
2482 | error = may_create(new_dir, new_dentry, NULL); | |
2483 | else | |
2484 | error = may_delete(new_dir, new_dentry, is_dir); | |
2485 | if (error) | |
2486 | return error; | |
2487 | ||
2488 | if (!old_dir->i_op || !old_dir->i_op->rename) | |
2489 | return -EPERM; | |
2490 | ||
2491 | DQUOT_INIT(old_dir); | |
2492 | DQUOT_INIT(new_dir); | |
2493 | ||
0eeca283 RL |
2494 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); |
2495 | ||
1da177e4 LT |
2496 | if (is_dir) |
2497 | error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); | |
2498 | else | |
2499 | error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); | |
2500 | if (!error) { | |
0eeca283 | 2501 | const char *new_name = old_dentry->d_name.name; |
89204c40 JM |
2502 | fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir, |
2503 | new_dentry->d_inode, old_dentry->d_inode); | |
1da177e4 | 2504 | } |
0eeca283 RL |
2505 | fsnotify_oldname_free(old_name); |
2506 | ||
1da177e4 LT |
2507 | return error; |
2508 | } | |
2509 | ||
5590ff0d UD |
2510 | static int do_rename(int olddfd, const char *oldname, |
2511 | int newdfd, const char *newname) | |
1da177e4 LT |
2512 | { |
2513 | int error = 0; | |
2514 | struct dentry * old_dir, * new_dir; | |
2515 | struct dentry * old_dentry, *new_dentry; | |
2516 | struct dentry * trap; | |
2517 | struct nameidata oldnd, newnd; | |
2518 | ||
5590ff0d | 2519 | error = do_path_lookup(olddfd, oldname, LOOKUP_PARENT, &oldnd); |
1da177e4 LT |
2520 | if (error) |
2521 | goto exit; | |
2522 | ||
5590ff0d | 2523 | error = do_path_lookup(newdfd, newname, LOOKUP_PARENT, &newnd); |
1da177e4 LT |
2524 | if (error) |
2525 | goto exit1; | |
2526 | ||
2527 | error = -EXDEV; | |
2528 | if (oldnd.mnt != newnd.mnt) | |
2529 | goto exit2; | |
2530 | ||
2531 | old_dir = oldnd.dentry; | |
2532 | error = -EBUSY; | |
2533 | if (oldnd.last_type != LAST_NORM) | |
2534 | goto exit2; | |
2535 | ||
2536 | new_dir = newnd.dentry; | |
2537 | if (newnd.last_type != LAST_NORM) | |
2538 | goto exit2; | |
2539 | ||
2540 | trap = lock_rename(new_dir, old_dir); | |
2541 | ||
49705b77 | 2542 | old_dentry = lookup_hash(&oldnd); |
1da177e4 LT |
2543 | error = PTR_ERR(old_dentry); |
2544 | if (IS_ERR(old_dentry)) | |
2545 | goto exit3; | |
2546 | /* source must exist */ | |
2547 | error = -ENOENT; | |
2548 | if (!old_dentry->d_inode) | |
2549 | goto exit4; | |
2550 | /* unless the source is a directory trailing slashes give -ENOTDIR */ | |
2551 | if (!S_ISDIR(old_dentry->d_inode->i_mode)) { | |
2552 | error = -ENOTDIR; | |
2553 | if (oldnd.last.name[oldnd.last.len]) | |
2554 | goto exit4; | |
2555 | if (newnd.last.name[newnd.last.len]) | |
2556 | goto exit4; | |
2557 | } | |
2558 | /* source should not be ancestor of target */ | |
2559 | error = -EINVAL; | |
2560 | if (old_dentry == trap) | |
2561 | goto exit4; | |
49705b77 | 2562 | new_dentry = lookup_hash(&newnd); |
1da177e4 LT |
2563 | error = PTR_ERR(new_dentry); |
2564 | if (IS_ERR(new_dentry)) | |
2565 | goto exit4; | |
2566 | /* target should not be an ancestor of source */ | |
2567 | error = -ENOTEMPTY; | |
2568 | if (new_dentry == trap) | |
2569 | goto exit5; | |
2570 | ||
2571 | error = vfs_rename(old_dir->d_inode, old_dentry, | |
2572 | new_dir->d_inode, new_dentry); | |
2573 | exit5: | |
2574 | dput(new_dentry); | |
2575 | exit4: | |
2576 | dput(old_dentry); | |
2577 | exit3: | |
2578 | unlock_rename(new_dir, old_dir); | |
2579 | exit2: | |
2580 | path_release(&newnd); | |
2581 | exit1: | |
2582 | path_release(&oldnd); | |
2583 | exit: | |
2584 | return error; | |
2585 | } | |
2586 | ||
5590ff0d UD |
2587 | asmlinkage long sys_renameat(int olddfd, const char __user *oldname, |
2588 | int newdfd, const char __user *newname) | |
1da177e4 LT |
2589 | { |
2590 | int error; | |
2591 | char * from; | |
2592 | char * to; | |
2593 | ||
2594 | from = getname(oldname); | |
2595 | if(IS_ERR(from)) | |
2596 | return PTR_ERR(from); | |
2597 | to = getname(newname); | |
2598 | error = PTR_ERR(to); | |
2599 | if (!IS_ERR(to)) { | |
5590ff0d | 2600 | error = do_rename(olddfd, from, newdfd, to); |
1da177e4 LT |
2601 | putname(to); |
2602 | } | |
2603 | putname(from); | |
2604 | return error; | |
2605 | } | |
2606 | ||
5590ff0d UD |
2607 | asmlinkage long sys_rename(const char __user *oldname, const char __user *newname) |
2608 | { | |
2609 | return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); | |
2610 | } | |
2611 | ||
1da177e4 LT |
2612 | int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) |
2613 | { | |
2614 | int len; | |
2615 | ||
2616 | len = PTR_ERR(link); | |
2617 | if (IS_ERR(link)) | |
2618 | goto out; | |
2619 | ||
2620 | len = strlen(link); | |
2621 | if (len > (unsigned) buflen) | |
2622 | len = buflen; | |
2623 | if (copy_to_user(buffer, link, len)) | |
2624 | len = -EFAULT; | |
2625 | out: | |
2626 | return len; | |
2627 | } | |
2628 | ||
2629 | /* | |
2630 | * A helper for ->readlink(). This should be used *ONLY* for symlinks that | |
2631 | * have ->follow_link() touching nd only in nd_set_link(). Using (or not | |
2632 | * using) it for any given inode is up to filesystem. | |
2633 | */ | |
2634 | int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) | |
2635 | { | |
2636 | struct nameidata nd; | |
cc314eef LT |
2637 | void *cookie; |
2638 | ||
1da177e4 | 2639 | nd.depth = 0; |
cc314eef LT |
2640 | cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); |
2641 | if (!IS_ERR(cookie)) { | |
2642 | int res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); | |
1da177e4 | 2643 | if (dentry->d_inode->i_op->put_link) |
cc314eef LT |
2644 | dentry->d_inode->i_op->put_link(dentry, &nd, cookie); |
2645 | cookie = ERR_PTR(res); | |
1da177e4 | 2646 | } |
cc314eef | 2647 | return PTR_ERR(cookie); |
1da177e4 LT |
2648 | } |
2649 | ||
2650 | int vfs_follow_link(struct nameidata *nd, const char *link) | |
2651 | { | |
2652 | return __vfs_follow_link(nd, link); | |
2653 | } | |
2654 | ||
2655 | /* get the link contents into pagecache */ | |
2656 | static char *page_getlink(struct dentry * dentry, struct page **ppage) | |
2657 | { | |
2658 | struct page * page; | |
2659 | struct address_space *mapping = dentry->d_inode->i_mapping; | |
090d2b18 | 2660 | page = read_mapping_page(mapping, 0, NULL); |
1da177e4 | 2661 | if (IS_ERR(page)) |
6fe6900e | 2662 | return (char*)page; |
1da177e4 LT |
2663 | *ppage = page; |
2664 | return kmap(page); | |
1da177e4 LT |
2665 | } |
2666 | ||
2667 | int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) | |
2668 | { | |
2669 | struct page *page = NULL; | |
2670 | char *s = page_getlink(dentry, &page); | |
2671 | int res = vfs_readlink(dentry,buffer,buflen,s); | |
2672 | if (page) { | |
2673 | kunmap(page); | |
2674 | page_cache_release(page); | |
2675 | } | |
2676 | return res; | |
2677 | } | |
2678 | ||
cc314eef | 2679 | void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 2680 | { |
cc314eef | 2681 | struct page *page = NULL; |
1da177e4 | 2682 | nd_set_link(nd, page_getlink(dentry, &page)); |
cc314eef | 2683 | return page; |
1da177e4 LT |
2684 | } |
2685 | ||
cc314eef | 2686 | void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 | 2687 | { |
cc314eef LT |
2688 | struct page *page = cookie; |
2689 | ||
2690 | if (page) { | |
1da177e4 LT |
2691 | kunmap(page); |
2692 | page_cache_release(page); | |
1da177e4 LT |
2693 | } |
2694 | } | |
2695 | ||
0adb25d2 KK |
2696 | int __page_symlink(struct inode *inode, const char *symname, int len, |
2697 | gfp_t gfp_mask) | |
1da177e4 LT |
2698 | { |
2699 | struct address_space *mapping = inode->i_mapping; | |
0adb25d2 | 2700 | struct page *page; |
beb497ab | 2701 | int err; |
1da177e4 LT |
2702 | char *kaddr; |
2703 | ||
7e53cac4 | 2704 | retry: |
beb497ab | 2705 | err = -ENOMEM; |
0adb25d2 | 2706 | page = find_or_create_page(mapping, 0, gfp_mask); |
1da177e4 LT |
2707 | if (!page) |
2708 | goto fail; | |
2709 | err = mapping->a_ops->prepare_write(NULL, page, 0, len-1); | |
7e53cac4 N |
2710 | if (err == AOP_TRUNCATED_PAGE) { |
2711 | page_cache_release(page); | |
2712 | goto retry; | |
2713 | } | |
1da177e4 LT |
2714 | if (err) |
2715 | goto fail_map; | |
2716 | kaddr = kmap_atomic(page, KM_USER0); | |
2717 | memcpy(kaddr, symname, len-1); | |
2718 | kunmap_atomic(kaddr, KM_USER0); | |
7e53cac4 N |
2719 | err = mapping->a_ops->commit_write(NULL, page, 0, len-1); |
2720 | if (err == AOP_TRUNCATED_PAGE) { | |
2721 | page_cache_release(page); | |
2722 | goto retry; | |
2723 | } | |
2724 | if (err) | |
2725 | goto fail_map; | |
1da177e4 LT |
2726 | /* |
2727 | * Notice that we are _not_ going to block here - end of page is | |
2728 | * unmapped, so this will only try to map the rest of page, see | |
2729 | * that it is unmapped (typically even will not look into inode - | |
2730 | * ->i_size will be enough for everything) and zero it out. | |
2731 | * OTOH it's obviously correct and should make the page up-to-date. | |
2732 | */ | |
2733 | if (!PageUptodate(page)) { | |
2734 | err = mapping->a_ops->readpage(NULL, page); | |
7e53cac4 N |
2735 | if (err != AOP_TRUNCATED_PAGE) |
2736 | wait_on_page_locked(page); | |
1da177e4 LT |
2737 | } else { |
2738 | unlock_page(page); | |
2739 | } | |
2740 | page_cache_release(page); | |
2741 | if (err < 0) | |
2742 | goto fail; | |
2743 | mark_inode_dirty(inode); | |
2744 | return 0; | |
2745 | fail_map: | |
2746 | unlock_page(page); | |
2747 | page_cache_release(page); | |
2748 | fail: | |
2749 | return err; | |
2750 | } | |
2751 | ||
0adb25d2 KK |
2752 | int page_symlink(struct inode *inode, const char *symname, int len) |
2753 | { | |
2754 | return __page_symlink(inode, symname, len, | |
2755 | mapping_gfp_mask(inode->i_mapping)); | |
2756 | } | |
2757 | ||
92e1d5be | 2758 | const struct inode_operations page_symlink_inode_operations = { |
1da177e4 LT |
2759 | .readlink = generic_readlink, |
2760 | .follow_link = page_follow_link_light, | |
2761 | .put_link = page_put_link, | |
2762 | }; | |
2763 | ||
2764 | EXPORT_SYMBOL(__user_walk); | |
5590ff0d | 2765 | EXPORT_SYMBOL(__user_walk_fd); |
1da177e4 LT |
2766 | EXPORT_SYMBOL(follow_down); |
2767 | EXPORT_SYMBOL(follow_up); | |
2768 | EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ | |
2769 | EXPORT_SYMBOL(getname); | |
2770 | EXPORT_SYMBOL(lock_rename); | |
1da177e4 LT |
2771 | EXPORT_SYMBOL(lookup_one_len); |
2772 | EXPORT_SYMBOL(page_follow_link_light); | |
2773 | EXPORT_SYMBOL(page_put_link); | |
2774 | EXPORT_SYMBOL(page_readlink); | |
0adb25d2 | 2775 | EXPORT_SYMBOL(__page_symlink); |
1da177e4 LT |
2776 | EXPORT_SYMBOL(page_symlink); |
2777 | EXPORT_SYMBOL(page_symlink_inode_operations); | |
2778 | EXPORT_SYMBOL(path_lookup); | |
2779 | EXPORT_SYMBOL(path_release); | |
2780 | EXPORT_SYMBOL(path_walk); | |
2781 | EXPORT_SYMBOL(permission); | |
e4543edd | 2782 | EXPORT_SYMBOL(vfs_permission); |
8c744fb8 | 2783 | EXPORT_SYMBOL(file_permission); |
1da177e4 LT |
2784 | EXPORT_SYMBOL(unlock_rename); |
2785 | EXPORT_SYMBOL(vfs_create); | |
2786 | EXPORT_SYMBOL(vfs_follow_link); | |
2787 | EXPORT_SYMBOL(vfs_link); | |
2788 | EXPORT_SYMBOL(vfs_mkdir); | |
2789 | EXPORT_SYMBOL(vfs_mknod); | |
2790 | EXPORT_SYMBOL(generic_permission); | |
2791 | EXPORT_SYMBOL(vfs_readlink); | |
2792 | EXPORT_SYMBOL(vfs_rename); | |
2793 | EXPORT_SYMBOL(vfs_rmdir); | |
2794 | EXPORT_SYMBOL(vfs_symlink); | |
2795 | EXPORT_SYMBOL(vfs_unlink); | |
2796 | EXPORT_SYMBOL(dentry_unhash); | |
2797 | EXPORT_SYMBOL(generic_readlink); |