4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * Some corrections by tytso.
11 /* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname
14 /* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture.
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
21 #include <linux/namei.h>
22 #include <linux/quotaops.h>
23 #include <linux/pagemap.h>
24 #include <linux/fsnotify.h>
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>
30 #include <linux/capability.h>
31 #include <linux/file.h>
32 #include <linux/fcntl.h>
33 #include <linux/device_cgroup.h>
34 #include <asm/uaccess.h>
36 #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
38 /* [Feb-1997 T. Schoebel-Theuer]
39 * Fundamental changes in the pathname lookup mechanisms (namei)
40 * were necessary because of omirr. The reason is that omirr needs
41 * to know the _real_ pathname, not the user-supplied one, in case
42 * of symlinks (and also when transname replacements occur).
44 * The new code replaces the old recursive symlink resolution with
45 * an iterative one (in case of non-nested symlink chains). It does
46 * this with calls to <fs>_follow_link().
47 * As a side effect, dir_namei(), _namei() and follow_link() are now
48 * replaced with a single function lookup_dentry() that can handle all
49 * the special cases of the former code.
51 * With the new dcache, the pathname is stored at each inode, at least as
52 * long as the refcount of the inode is positive. As a side effect, the
53 * size of the dcache depends on the inode cache and thus is dynamic.
55 * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink
56 * resolution to correspond with current state of the code.
58 * Note that the symlink resolution is not *completely* iterative.
59 * There is still a significant amount of tail- and mid- recursion in
60 * the algorithm. Also, note that <fs>_readlink() is not used in
61 * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink()
62 * may return different results than <fs>_follow_link(). Many virtual
63 * filesystems (including /proc) exhibit this behavior.
66 /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation:
67 * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL
68 * and the name already exists in form of a symlink, try to create the new
69 * name indicated by the symlink. The old code always complained that the
70 * name already exists, due to not following the symlink even if its target
71 * is nonexistent. The new semantics affects also mknod() and link() when
72 * the name is a symlink pointing to a non-existant name.
74 * I don't know which semantics is the right one, since I have no access
75 * to standards. But I found by trial that HP-UX 9.0 has the full "new"
76 * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the
77 * "old" one. Personally, I think the new semantics is much more logical.
78 * Note that "ln old new" where "new" is a symlink pointing to a non-existing
79 * file does succeed in both HP-UX and SunOs, but not in Solaris
80 * and in the old Linux semantics.
83 /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink
84 * semantics. See the comments in "open_namei" and "do_link" below.
86 * [10-Sep-98 Alan Modra] Another symlink change.
89 /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks:
90 * inside the path - always follow.
91 * in the last component in creation/removal/renaming - never follow.
92 * if LOOKUP_FOLLOW passed - follow.
93 * if the pathname has trailing slashes - follow.
94 * otherwise - don't follow.
95 * (applied in that order).
97 * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT
98 * restored for 2.4. This is the last surviving part of old 4.2BSD bug.
99 * During the 2.4 we need to fix the userland stuff depending on it -
100 * hopefully we will be able to get rid of that wart in 2.5. So far only
101 * XEmacs seems to be relying on it...
104 * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland)
105 * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives
106 * any extra contention...
109 static int __link_path_walk(const char *name
, struct nameidata
*nd
);
111 /* In order to reduce some races, while at the same time doing additional
112 * checking and hopefully speeding things up, we copy filenames to the
113 * kernel data space before using them..
115 * POSIX.1 2.4: an empty pathname is invalid (ENOENT).
116 * PATH_MAX includes the nul terminator --RR.
118 static int do_getname(const char __user
*filename
, char *page
)
121 unsigned long len
= PATH_MAX
;
123 if (!segment_eq(get_fs(), KERNEL_DS
)) {
124 if ((unsigned long) filename
>= TASK_SIZE
)
126 if (TASK_SIZE
- (unsigned long) filename
< PATH_MAX
)
127 len
= TASK_SIZE
- (unsigned long) filename
;
130 retval
= strncpy_from_user(page
, filename
, len
);
134 return -ENAMETOOLONG
;
140 char * getname(const char __user
* filename
)
144 result
= ERR_PTR(-ENOMEM
);
147 int retval
= do_getname(filename
, tmp
);
152 result
= ERR_PTR(retval
);
155 audit_getname(result
);
159 #ifdef CONFIG_AUDITSYSCALL
160 void putname(const char *name
)
162 if (unlikely(!audit_dummy_context()))
167 EXPORT_SYMBOL(putname
);
172 * generic_permission - check for access rights on a Posix-like filesystem
173 * @inode: inode to check access rights for
174 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
175 * @check_acl: optional callback to check for Posix ACLs
177 * Used to check for read/write/execute permissions on a file.
178 * We use "fsuid" for this, letting us set arbitrary permissions
179 * for filesystem access without changing the "normal" uids which
180 * are used for other things..
182 int generic_permission(struct inode
*inode
, int mask
,
183 int (*check_acl
)(struct inode
*inode
, int mask
))
185 umode_t mode
= inode
->i_mode
;
187 mask
&= MAY_READ
| MAY_WRITE
| MAY_EXEC
;
189 if (current
->fsuid
== inode
->i_uid
)
192 if (IS_POSIXACL(inode
) && (mode
& S_IRWXG
) && check_acl
) {
193 int error
= check_acl(inode
, mask
);
194 if (error
== -EACCES
)
195 goto check_capabilities
;
196 else if (error
!= -EAGAIN
)
200 if (in_group_p(inode
->i_gid
))
205 * If the DACs are ok we don't need any capability check.
207 if ((mask
& ~mode
) == 0)
212 * Read/write DACs are always overridable.
213 * Executable DACs are overridable if at least one exec bit is set.
215 if (!(mask
& MAY_EXEC
) ||
216 (inode
->i_mode
& S_IXUGO
) || S_ISDIR(inode
->i_mode
))
217 if (capable(CAP_DAC_OVERRIDE
))
221 * Searching includes executable on directories, else just read.
223 if (mask
== MAY_READ
|| (S_ISDIR(inode
->i_mode
) && !(mask
& MAY_WRITE
)))
224 if (capable(CAP_DAC_READ_SEARCH
))
230 int inode_permission(struct inode
*inode
, int mask
)
234 if (mask
& MAY_WRITE
) {
235 umode_t mode
= inode
->i_mode
;
238 * Nobody gets write access to a read-only fs.
240 if (IS_RDONLY(inode
) &&
241 (S_ISREG(mode
) || S_ISDIR(mode
) || S_ISLNK(mode
)))
245 * Nobody gets write access to an immutable file.
247 if (IS_IMMUTABLE(inode
))
251 /* Ordinary permission routines do not understand MAY_APPEND. */
252 if (inode
->i_op
&& inode
->i_op
->permission
) {
253 retval
= inode
->i_op
->permission(inode
, mask
);
256 * Exec permission on a regular file is denied if none
257 * of the execute bits are set.
259 * This check should be done by the ->permission()
262 if ((mask
& MAY_EXEC
) && S_ISREG(inode
->i_mode
) &&
263 !(inode
->i_mode
& S_IXUGO
))
267 retval
= generic_permission(inode
, mask
, NULL
);
272 retval
= devcgroup_inode_permission(inode
, mask
);
276 return security_inode_permission(inode
,
277 mask
& (MAY_READ
|MAY_WRITE
|MAY_EXEC
|MAY_APPEND
));
281 * vfs_permission - check for access rights to a given path
282 * @nd: lookup result that describes the path
283 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
285 * Used to check for read/write/execute permissions on a path.
286 * We use "fsuid" for this, letting us set arbitrary permissions
287 * for filesystem access without changing the "normal" uids which
288 * are used for other things.
290 int vfs_permission(struct nameidata
*nd
, int mask
)
292 return inode_permission(nd
->path
.dentry
->d_inode
, mask
);
296 * file_permission - check for additional access rights to a given file
297 * @file: file to check access rights for
298 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
300 * Used to check for read/write/execute permissions on an already opened
304 * Do not use this function in new code. All access checks should
305 * be done using vfs_permission().
307 int file_permission(struct file
*file
, int mask
)
309 return inode_permission(file
->f_path
.dentry
->d_inode
, mask
);
313 * get_write_access() gets write permission for a file.
314 * put_write_access() releases this write permission.
315 * This is used for regular files.
316 * We cannot support write (and maybe mmap read-write shared) accesses and
317 * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
318 * can have the following values:
319 * 0: no writers, no VM_DENYWRITE mappings
320 * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
321 * > 0: (i_writecount) users are writing to the file.
323 * Normally we operate on that counter with atomic_{inc,dec} and it's safe
324 * except for the cases where we don't hold i_writecount yet. Then we need to
325 * use {get,deny}_write_access() - these functions check the sign and refuse
326 * to do the change if sign is wrong. Exclusion between them is provided by
327 * the inode->i_lock spinlock.
330 int get_write_access(struct inode
* inode
)
332 spin_lock(&inode
->i_lock
);
333 if (atomic_read(&inode
->i_writecount
) < 0) {
334 spin_unlock(&inode
->i_lock
);
337 atomic_inc(&inode
->i_writecount
);
338 spin_unlock(&inode
->i_lock
);
343 int deny_write_access(struct file
* file
)
345 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
347 spin_lock(&inode
->i_lock
);
348 if (atomic_read(&inode
->i_writecount
) > 0) {
349 spin_unlock(&inode
->i_lock
);
352 atomic_dec(&inode
->i_writecount
);
353 spin_unlock(&inode
->i_lock
);
359 * path_get - get a reference to a path
360 * @path: path to get the reference to
362 * Given a path increment the reference count to the dentry and the vfsmount.
364 void path_get(struct path
*path
)
369 EXPORT_SYMBOL(path_get
);
372 * path_put - put a reference to a path
373 * @path: path to put the reference to
375 * Given a path decrement the reference count to the dentry and the vfsmount.
377 void path_put(struct path
*path
)
382 EXPORT_SYMBOL(path_put
);
385 * release_open_intent - free up open intent resources
386 * @nd: pointer to nameidata
388 void release_open_intent(struct nameidata
*nd
)
390 if (nd
->intent
.open
.file
->f_path
.dentry
== NULL
)
391 put_filp(nd
->intent
.open
.file
);
393 fput(nd
->intent
.open
.file
);
396 static inline struct dentry
*
397 do_revalidate(struct dentry
*dentry
, struct nameidata
*nd
)
399 int status
= dentry
->d_op
->d_revalidate(dentry
, nd
);
400 if (unlikely(status
<= 0)) {
402 * The dentry failed validation.
403 * If d_revalidate returned 0 attempt to invalidate
404 * the dentry otherwise d_revalidate is asking us
405 * to return a fail status.
408 if (!d_invalidate(dentry
)) {
414 dentry
= ERR_PTR(status
);
421 * Internal lookup() using the new generic dcache.
424 static struct dentry
* cached_lookup(struct dentry
* parent
, struct qstr
* name
, struct nameidata
*nd
)
426 struct dentry
* dentry
= __d_lookup(parent
, name
);
428 /* lockess __d_lookup may fail due to concurrent d_move()
429 * in some unrelated directory, so try with d_lookup
432 dentry
= d_lookup(parent
, name
);
434 if (dentry
&& dentry
->d_op
&& dentry
->d_op
->d_revalidate
)
435 dentry
= do_revalidate(dentry
, nd
);
441 * Short-cut version of permission(), for calling by
442 * path_walk(), when dcache lock is held. Combines parts
443 * of permission() and generic_permission(), and tests ONLY for
444 * MAY_EXEC permission.
446 * If appropriate, check DAC only. If not appropriate, or
447 * short-cut DAC fails, then call permission() to do more
448 * complete permission check.
450 static int exec_permission_lite(struct inode
*inode
)
452 umode_t mode
= inode
->i_mode
;
454 if (inode
->i_op
&& inode
->i_op
->permission
)
457 if (current
->fsuid
== inode
->i_uid
)
459 else if (in_group_p(inode
->i_gid
))
465 if ((inode
->i_mode
& S_IXUGO
) && capable(CAP_DAC_OVERRIDE
))
468 if (S_ISDIR(inode
->i_mode
) && capable(CAP_DAC_OVERRIDE
))
471 if (S_ISDIR(inode
->i_mode
) && capable(CAP_DAC_READ_SEARCH
))
476 return security_inode_permission(inode
, MAY_EXEC
);
480 * This is called when everything else fails, and we actually have
481 * to go to the low-level filesystem to find out what we should do..
483 * We get the directory semaphore, and after getting that we also
484 * make sure that nobody added the entry to the dcache in the meantime..
487 static struct dentry
* real_lookup(struct dentry
* parent
, struct qstr
* name
, struct nameidata
*nd
)
489 struct dentry
* result
;
490 struct inode
*dir
= parent
->d_inode
;
492 mutex_lock(&dir
->i_mutex
);
494 * First re-do the cached lookup just in case it was created
495 * while we waited for the directory semaphore..
497 * FIXME! This could use version numbering or similar to
498 * avoid unnecessary cache lookups.
500 * The "dcache_lock" is purely to protect the RCU list walker
501 * from concurrent renames at this point (we mustn't get false
502 * negatives from the RCU list walk here, unlike the optimistic
505 * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
507 result
= d_lookup(parent
, name
);
509 struct dentry
*dentry
;
511 /* Don't create child dentry for a dead directory. */
512 result
= ERR_PTR(-ENOENT
);
516 dentry
= d_alloc(parent
, name
);
517 result
= ERR_PTR(-ENOMEM
);
519 result
= dir
->i_op
->lookup(dir
, dentry
, nd
);
526 mutex_unlock(&dir
->i_mutex
);
531 * Uhhuh! Nasty case: the cache was re-populated while
532 * we waited on the semaphore. Need to revalidate.
534 mutex_unlock(&dir
->i_mutex
);
535 if (result
->d_op
&& result
->d_op
->d_revalidate
) {
536 result
= do_revalidate(result
, nd
);
538 result
= ERR_PTR(-ENOENT
);
544 static __always_inline
void
545 walk_init_root(const char *name
, struct nameidata
*nd
)
547 struct fs_struct
*fs
= current
->fs
;
549 read_lock(&fs
->lock
);
552 read_unlock(&fs
->lock
);
556 * Wrapper to retry pathname resolution whenever the underlying
557 * file system returns an ESTALE.
559 * Retry the whole path once, forcing real lookup requests
560 * instead of relying on the dcache.
562 static __always_inline
int link_path_walk(const char *name
, struct nameidata
*nd
)
564 struct path save
= nd
->path
;
567 /* make sure the stuff we saved doesn't go away */
570 result
= __link_path_walk(name
, nd
);
571 if (result
== -ESTALE
) {
572 /* nd->path had been dropped */
575 nd
->flags
|= LOOKUP_REVAL
;
576 result
= __link_path_walk(name
, nd
);
584 static __always_inline
int __vfs_follow_link(struct nameidata
*nd
, const char *link
)
593 walk_init_root(link
, nd
);
595 res
= link_path_walk(link
, nd
);
596 if (nd
->depth
|| res
|| nd
->last_type
!=LAST_NORM
)
599 * If it is an iterative symlinks resolution in open_namei() we
600 * have to copy the last component. And all that crap because of
601 * bloody create() on broken symlinks. Furrfu...
604 if (unlikely(!name
)) {
608 strcpy(name
, nd
->last
.name
);
609 nd
->last
.name
= name
;
613 return PTR_ERR(link
);
616 static void path_put_conditional(struct path
*path
, struct nameidata
*nd
)
619 if (path
->mnt
!= nd
->path
.mnt
)
623 static inline void path_to_nameidata(struct path
*path
, struct nameidata
*nd
)
625 dput(nd
->path
.dentry
);
626 if (nd
->path
.mnt
!= path
->mnt
)
627 mntput(nd
->path
.mnt
);
628 nd
->path
.mnt
= path
->mnt
;
629 nd
->path
.dentry
= path
->dentry
;
632 static __always_inline
int __do_follow_link(struct path
*path
, struct nameidata
*nd
)
636 struct dentry
*dentry
= path
->dentry
;
638 touch_atime(path
->mnt
, dentry
);
639 nd_set_link(nd
, NULL
);
641 if (path
->mnt
!= nd
->path
.mnt
) {
642 path_to_nameidata(path
, nd
);
646 cookie
= dentry
->d_inode
->i_op
->follow_link(dentry
, nd
);
647 error
= PTR_ERR(cookie
);
648 if (!IS_ERR(cookie
)) {
649 char *s
= nd_get_link(nd
);
652 error
= __vfs_follow_link(nd
, s
);
653 if (dentry
->d_inode
->i_op
->put_link
)
654 dentry
->d_inode
->i_op
->put_link(dentry
, nd
, cookie
);
662 * This limits recursive symlink follows to 8, while
663 * limiting consecutive symlinks to 40.
665 * Without that kind of total limit, nasty chains of consecutive
666 * symlinks can cause almost arbitrarily long lookups.
668 static inline int do_follow_link(struct path
*path
, struct nameidata
*nd
)
671 if (current
->link_count
>= MAX_NESTED_LINKS
)
673 if (current
->total_link_count
>= 40)
675 BUG_ON(nd
->depth
>= MAX_NESTED_LINKS
);
677 err
= security_inode_follow_link(path
->dentry
, nd
);
680 current
->link_count
++;
681 current
->total_link_count
++;
683 err
= __do_follow_link(path
, nd
);
684 current
->link_count
--;
688 path_put_conditional(path
, nd
);
693 int follow_up(struct vfsmount
**mnt
, struct dentry
**dentry
)
695 struct vfsmount
*parent
;
696 struct dentry
*mountpoint
;
697 spin_lock(&vfsmount_lock
);
698 parent
=(*mnt
)->mnt_parent
;
699 if (parent
== *mnt
) {
700 spin_unlock(&vfsmount_lock
);
704 mountpoint
=dget((*mnt
)->mnt_mountpoint
);
705 spin_unlock(&vfsmount_lock
);
707 *dentry
= mountpoint
;
713 /* no need for dcache_lock, as serialization is taken care in
716 static int __follow_mount(struct path
*path
)
719 while (d_mountpoint(path
->dentry
)) {
720 struct vfsmount
*mounted
= lookup_mnt(path
->mnt
, path
->dentry
);
727 path
->dentry
= dget(mounted
->mnt_root
);
733 static void follow_mount(struct vfsmount
**mnt
, struct dentry
**dentry
)
735 while (d_mountpoint(*dentry
)) {
736 struct vfsmount
*mounted
= lookup_mnt(*mnt
, *dentry
);
742 *dentry
= dget(mounted
->mnt_root
);
746 /* no need for dcache_lock, as serialization is taken care in
749 int follow_down(struct vfsmount
**mnt
, struct dentry
**dentry
)
751 struct vfsmount
*mounted
;
753 mounted
= lookup_mnt(*mnt
, *dentry
);
758 *dentry
= dget(mounted
->mnt_root
);
764 static __always_inline
void follow_dotdot(struct nameidata
*nd
)
766 struct fs_struct
*fs
= current
->fs
;
769 struct vfsmount
*parent
;
770 struct dentry
*old
= nd
->path
.dentry
;
772 read_lock(&fs
->lock
);
773 if (nd
->path
.dentry
== fs
->root
.dentry
&&
774 nd
->path
.mnt
== fs
->root
.mnt
) {
775 read_unlock(&fs
->lock
);
778 read_unlock(&fs
->lock
);
779 spin_lock(&dcache_lock
);
780 if (nd
->path
.dentry
!= nd
->path
.mnt
->mnt_root
) {
781 nd
->path
.dentry
= dget(nd
->path
.dentry
->d_parent
);
782 spin_unlock(&dcache_lock
);
786 spin_unlock(&dcache_lock
);
787 spin_lock(&vfsmount_lock
);
788 parent
= nd
->path
.mnt
->mnt_parent
;
789 if (parent
== nd
->path
.mnt
) {
790 spin_unlock(&vfsmount_lock
);
794 nd
->path
.dentry
= dget(nd
->path
.mnt
->mnt_mountpoint
);
795 spin_unlock(&vfsmount_lock
);
797 mntput(nd
->path
.mnt
);
798 nd
->path
.mnt
= parent
;
800 follow_mount(&nd
->path
.mnt
, &nd
->path
.dentry
);
804 * It's more convoluted than I'd like it to be, but... it's still fairly
805 * small and for now I'd prefer to have fast path as straight as possible.
806 * It _is_ time-critical.
808 static int do_lookup(struct nameidata
*nd
, struct qstr
*name
,
811 struct vfsmount
*mnt
= nd
->path
.mnt
;
812 struct dentry
*dentry
= __d_lookup(nd
->path
.dentry
, name
);
816 if (dentry
->d_op
&& dentry
->d_op
->d_revalidate
)
817 goto need_revalidate
;
820 path
->dentry
= dentry
;
821 __follow_mount(path
);
825 dentry
= real_lookup(nd
->path
.dentry
, name
, nd
);
831 dentry
= do_revalidate(dentry
, nd
);
839 return PTR_ERR(dentry
);
844 * This is the basic name resolution function, turning a pathname into
845 * the final dentry. We expect 'base' to be positive and a directory.
847 * Returns 0 and nd will have valid dentry and mnt on success.
848 * Returns error and drops reference to input namei data on failure.
850 static int __link_path_walk(const char *name
, struct nameidata
*nd
)
855 unsigned int lookup_flags
= nd
->flags
;
862 inode
= nd
->path
.dentry
->d_inode
;
864 lookup_flags
= LOOKUP_FOLLOW
| (nd
->flags
& LOOKUP_CONTINUE
);
866 /* At this point we know we have a real path component. */
872 nd
->flags
|= LOOKUP_CONTINUE
;
873 err
= exec_permission_lite(inode
);
875 err
= vfs_permission(nd
, MAY_EXEC
);
880 c
= *(const unsigned char *)name
;
882 hash
= init_name_hash();
885 hash
= partial_name_hash(c
, hash
);
886 c
= *(const unsigned char *)name
;
887 } while (c
&& (c
!= '/'));
888 this.len
= name
- (const char *) this.name
;
889 this.hash
= end_name_hash(hash
);
891 /* remove trailing slashes? */
894 while (*++name
== '/');
896 goto last_with_slashes
;
899 * "." and ".." are special - ".." especially so because it has
900 * to be able to know about the current root directory and
901 * parent relationships.
903 if (this.name
[0] == '.') switch (this.len
) {
907 if (this.name
[1] != '.')
910 inode
= nd
->path
.dentry
->d_inode
;
916 * See if the low-level filesystem might want
917 * to use its own hash..
919 if (nd
->path
.dentry
->d_op
&& nd
->path
.dentry
->d_op
->d_hash
) {
920 err
= nd
->path
.dentry
->d_op
->d_hash(nd
->path
.dentry
,
925 /* This does the actual lookups.. */
926 err
= do_lookup(nd
, &this, &next
);
931 inode
= next
.dentry
->d_inode
;
938 if (inode
->i_op
->follow_link
) {
939 err
= do_follow_link(&next
, nd
);
943 inode
= nd
->path
.dentry
->d_inode
;
950 path_to_nameidata(&next
, nd
);
952 if (!inode
->i_op
->lookup
)
955 /* here ends the main loop */
958 lookup_flags
|= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
960 /* Clear LOOKUP_CONTINUE iff it was previously unset */
961 nd
->flags
&= lookup_flags
| ~LOOKUP_CONTINUE
;
962 if (lookup_flags
& LOOKUP_PARENT
)
964 if (this.name
[0] == '.') switch (this.len
) {
968 if (this.name
[1] != '.')
971 inode
= nd
->path
.dentry
->d_inode
;
976 if (nd
->path
.dentry
->d_op
&& nd
->path
.dentry
->d_op
->d_hash
) {
977 err
= nd
->path
.dentry
->d_op
->d_hash(nd
->path
.dentry
,
982 err
= do_lookup(nd
, &this, &next
);
985 inode
= next
.dentry
->d_inode
;
986 if ((lookup_flags
& LOOKUP_FOLLOW
)
987 && inode
&& inode
->i_op
&& inode
->i_op
->follow_link
) {
988 err
= do_follow_link(&next
, nd
);
991 inode
= nd
->path
.dentry
->d_inode
;
993 path_to_nameidata(&next
, nd
);
997 if (lookup_flags
& LOOKUP_DIRECTORY
) {
999 if (!inode
->i_op
|| !inode
->i_op
->lookup
)
1005 nd
->last_type
= LAST_NORM
;
1006 if (this.name
[0] != '.')
1009 nd
->last_type
= LAST_DOT
;
1010 else if (this.len
== 2 && this.name
[1] == '.')
1011 nd
->last_type
= LAST_DOTDOT
;
1016 * We bypassed the ordinary revalidation routines.
1017 * We may need to check the cached dentry for staleness.
1019 if (nd
->path
.dentry
&& nd
->path
.dentry
->d_sb
&&
1020 (nd
->path
.dentry
->d_sb
->s_type
->fs_flags
& FS_REVAL_DOT
)) {
1022 /* Note: we do not d_invalidate() */
1023 if (!nd
->path
.dentry
->d_op
->d_revalidate(
1024 nd
->path
.dentry
, nd
))
1030 path_put_conditional(&next
, nd
);
1033 path_put(&nd
->path
);
1038 static int path_walk(const char *name
, struct nameidata
*nd
)
1040 current
->total_link_count
= 0;
1041 return link_path_walk(name
, nd
);
1044 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
1045 static int do_path_lookup(int dfd
, const char *name
,
1046 unsigned int flags
, struct nameidata
*nd
)
1051 struct fs_struct
*fs
= current
->fs
;
1053 nd
->last_type
= LAST_ROOT
; /* if there are only slashes... */
1058 read_lock(&fs
->lock
);
1059 nd
->path
= fs
->root
;
1060 path_get(&fs
->root
);
1061 read_unlock(&fs
->lock
);
1062 } else if (dfd
== AT_FDCWD
) {
1063 read_lock(&fs
->lock
);
1066 read_unlock(&fs
->lock
);
1068 struct dentry
*dentry
;
1070 file
= fget_light(dfd
, &fput_needed
);
1075 dentry
= file
->f_path
.dentry
;
1078 if (!S_ISDIR(dentry
->d_inode
->i_mode
))
1081 retval
= file_permission(file
, MAY_EXEC
);
1085 nd
->path
= file
->f_path
;
1086 path_get(&file
->f_path
);
1088 fput_light(file
, fput_needed
);
1091 retval
= path_walk(name
, nd
);
1092 if (unlikely(!retval
&& !audit_dummy_context() && nd
->path
.dentry
&&
1093 nd
->path
.dentry
->d_inode
))
1094 audit_inode(name
, nd
->path
.dentry
);
1099 fput_light(file
, fput_needed
);
1103 int path_lookup(const char *name
, unsigned int flags
,
1104 struct nameidata
*nd
)
1106 return do_path_lookup(AT_FDCWD
, name
, flags
, nd
);
1109 int kern_path(const char *name
, unsigned int flags
, struct path
*path
)
1111 struct nameidata nd
;
1112 int res
= do_path_lookup(AT_FDCWD
, name
, flags
, &nd
);
1119 * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
1120 * @dentry: pointer to dentry of the base directory
1121 * @mnt: pointer to vfs mount of the base directory
1122 * @name: pointer to file name
1123 * @flags: lookup flags
1124 * @nd: pointer to nameidata
1126 int vfs_path_lookup(struct dentry
*dentry
, struct vfsmount
*mnt
,
1127 const char *name
, unsigned int flags
,
1128 struct nameidata
*nd
)
1132 /* same as do_path_lookup */
1133 nd
->last_type
= LAST_ROOT
;
1137 nd
->path
.dentry
= dentry
;
1139 path_get(&nd
->path
);
1141 retval
= path_walk(name
, nd
);
1142 if (unlikely(!retval
&& !audit_dummy_context() && nd
->path
.dentry
&&
1143 nd
->path
.dentry
->d_inode
))
1144 audit_inode(name
, nd
->path
.dentry
);
1150 static int __path_lookup_intent_open(int dfd
, const char *name
,
1151 unsigned int lookup_flags
, struct nameidata
*nd
,
1152 int open_flags
, int create_mode
)
1154 struct file
*filp
= get_empty_filp();
1159 nd
->intent
.open
.file
= filp
;
1160 nd
->intent
.open
.flags
= open_flags
;
1161 nd
->intent
.open
.create_mode
= create_mode
;
1162 err
= do_path_lookup(dfd
, name
, lookup_flags
|LOOKUP_OPEN
, nd
);
1163 if (IS_ERR(nd
->intent
.open
.file
)) {
1165 err
= PTR_ERR(nd
->intent
.open
.file
);
1166 path_put(&nd
->path
);
1168 } else if (err
!= 0)
1169 release_open_intent(nd
);
1174 * path_lookup_open - lookup a file path with open intent
1175 * @dfd: the directory to use as base, or AT_FDCWD
1176 * @name: pointer to file name
1177 * @lookup_flags: lookup intent flags
1178 * @nd: pointer to nameidata
1179 * @open_flags: open intent flags
1181 int path_lookup_open(int dfd
, const char *name
, unsigned int lookup_flags
,
1182 struct nameidata
*nd
, int open_flags
)
1184 return __path_lookup_intent_open(dfd
, name
, lookup_flags
, nd
,
1189 * path_lookup_create - lookup a file path with open + create intent
1190 * @dfd: the directory to use as base, or AT_FDCWD
1191 * @name: pointer to file name
1192 * @lookup_flags: lookup intent flags
1193 * @nd: pointer to nameidata
1194 * @open_flags: open intent flags
1195 * @create_mode: create intent flags
1197 static int path_lookup_create(int dfd
, const char *name
,
1198 unsigned int lookup_flags
, struct nameidata
*nd
,
1199 int open_flags
, int create_mode
)
1201 return __path_lookup_intent_open(dfd
, name
, lookup_flags
|LOOKUP_CREATE
,
1202 nd
, open_flags
, create_mode
);
1205 static struct dentry
*__lookup_hash(struct qstr
*name
,
1206 struct dentry
*base
, struct nameidata
*nd
)
1208 struct dentry
*dentry
;
1209 struct inode
*inode
;
1212 inode
= base
->d_inode
;
1215 * See if the low-level filesystem might want
1216 * to use its own hash..
1218 if (base
->d_op
&& base
->d_op
->d_hash
) {
1219 err
= base
->d_op
->d_hash(base
, name
);
1220 dentry
= ERR_PTR(err
);
1225 dentry
= cached_lookup(base
, name
, nd
);
1229 /* Don't create child dentry for a dead directory. */
1230 dentry
= ERR_PTR(-ENOENT
);
1231 if (IS_DEADDIR(inode
))
1234 new = d_alloc(base
, name
);
1235 dentry
= ERR_PTR(-ENOMEM
);
1238 dentry
= inode
->i_op
->lookup(inode
, new, nd
);
1249 * Restricted form of lookup. Doesn't follow links, single-component only,
1250 * needs parent already locked. Doesn't follow mounts.
1253 static struct dentry
*lookup_hash(struct nameidata
*nd
)
1257 err
= inode_permission(nd
->path
.dentry
->d_inode
, MAY_EXEC
);
1259 return ERR_PTR(err
);
1260 return __lookup_hash(&nd
->last
, nd
->path
.dentry
, nd
);
1263 static int __lookup_one_len(const char *name
, struct qstr
*this,
1264 struct dentry
*base
, int len
)
1274 hash
= init_name_hash();
1276 c
= *(const unsigned char *)name
++;
1277 if (c
== '/' || c
== '\0')
1279 hash
= partial_name_hash(c
, hash
);
1281 this->hash
= end_name_hash(hash
);
1286 * lookup_one_len - filesystem helper to lookup single pathname component
1287 * @name: pathname component to lookup
1288 * @base: base directory to lookup from
1289 * @len: maximum length @len should be interpreted to
1291 * Note that this routine is purely a helper for filesystem usage and should
1292 * not be called by generic code. Also note that by using this function the
1293 * nameidata argument is passed to the filesystem methods and a filesystem
1294 * using this helper needs to be prepared for that.
1296 struct dentry
*lookup_one_len(const char *name
, struct dentry
*base
, int len
)
1301 err
= __lookup_one_len(name
, &this, base
, len
);
1303 return ERR_PTR(err
);
1305 err
= inode_permission(base
->d_inode
, MAY_EXEC
);
1307 return ERR_PTR(err
);
1308 return __lookup_hash(&this, base
, NULL
);
1312 * lookup_one_noperm - bad hack for sysfs
1313 * @name: pathname component to lookup
1314 * @base: base directory to lookup from
1316 * This is a variant of lookup_one_len that doesn't perform any permission
1317 * checks. It's a horrible hack to work around the braindead sysfs
1318 * architecture and should not be used anywhere else.
1320 * DON'T USE THIS FUNCTION EVER, thanks.
1322 struct dentry
*lookup_one_noperm(const char *name
, struct dentry
*base
)
1327 err
= __lookup_one_len(name
, &this, base
, strlen(name
));
1329 return ERR_PTR(err
);
1330 return __lookup_hash(&this, base
, NULL
);
1333 int user_path_at(int dfd
, const char __user
*name
, unsigned flags
,
1336 struct nameidata nd
;
1337 char *tmp
= getname(name
);
1338 int err
= PTR_ERR(tmp
);
1341 BUG_ON(flags
& LOOKUP_PARENT
);
1343 err
= do_path_lookup(dfd
, tmp
, flags
, &nd
);
1351 static int user_path_parent(int dfd
, const char __user
*path
,
1352 struct nameidata
*nd
, char **name
)
1354 char *s
= getname(path
);
1360 error
= do_path_lookup(dfd
, s
, LOOKUP_PARENT
, nd
);
1370 * It's inline, so penalty for filesystems that don't use sticky bit is
1373 static inline int check_sticky(struct inode
*dir
, struct inode
*inode
)
1375 if (!(dir
->i_mode
& S_ISVTX
))
1377 if (inode
->i_uid
== current
->fsuid
)
1379 if (dir
->i_uid
== current
->fsuid
)
1381 return !capable(CAP_FOWNER
);
1385 * Check whether we can remove a link victim from directory dir, check
1386 * whether the type of victim is right.
1387 * 1. We can't do it if dir is read-only (done in permission())
1388 * 2. We should have write and exec permissions on dir
1389 * 3. We can't remove anything from append-only dir
1390 * 4. We can't do anything with immutable dir (done in permission())
1391 * 5. If the sticky bit on dir is set we should either
1392 * a. be owner of dir, or
1393 * b. be owner of victim, or
1394 * c. have CAP_FOWNER capability
1395 * 6. If the victim is append-only or immutable we can't do antyhing with
1396 * links pointing to it.
1397 * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
1398 * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
1399 * 9. We can't remove a root or mountpoint.
1400 * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
1401 * nfs_async_unlink().
1403 static int may_delete(struct inode
*dir
,struct dentry
*victim
,int isdir
)
1407 if (!victim
->d_inode
)
1410 BUG_ON(victim
->d_parent
->d_inode
!= dir
);
1411 audit_inode_child(victim
->d_name
.name
, victim
, dir
);
1413 error
= inode_permission(dir
, MAY_WRITE
| MAY_EXEC
);
1418 if (check_sticky(dir
, victim
->d_inode
)||IS_APPEND(victim
->d_inode
)||
1419 IS_IMMUTABLE(victim
->d_inode
))
1422 if (!S_ISDIR(victim
->d_inode
->i_mode
))
1424 if (IS_ROOT(victim
))
1426 } else if (S_ISDIR(victim
->d_inode
->i_mode
))
1428 if (IS_DEADDIR(dir
))
1430 if (victim
->d_flags
& DCACHE_NFSFS_RENAMED
)
1435 /* Check whether we can create an object with dentry child in directory
1437 * 1. We can't do it if child already exists (open has special treatment for
1438 * this case, but since we are inlined it's OK)
1439 * 2. We can't do it if dir is read-only (done in permission())
1440 * 3. We should have write and exec permissions on dir
1441 * 4. We can't do it if dir is immutable (done in permission())
1443 static inline int may_create(struct inode
*dir
, struct dentry
*child
)
1447 if (IS_DEADDIR(dir
))
1449 return inode_permission(dir
, MAY_WRITE
| MAY_EXEC
);
1453 * O_DIRECTORY translates into forcing a directory lookup.
1455 static inline int lookup_flags(unsigned int f
)
1457 unsigned long retval
= LOOKUP_FOLLOW
;
1460 retval
&= ~LOOKUP_FOLLOW
;
1462 if (f
& O_DIRECTORY
)
1463 retval
|= LOOKUP_DIRECTORY
;
1469 * p1 and p2 should be directories on the same fs.
1471 struct dentry
*lock_rename(struct dentry
*p1
, struct dentry
*p2
)
1476 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1480 mutex_lock(&p1
->d_inode
->i_sb
->s_vfs_rename_mutex
);
1482 for (p
= p1
; p
->d_parent
!= p
; p
= p
->d_parent
) {
1483 if (p
->d_parent
== p2
) {
1484 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1485 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1490 for (p
= p2
; p
->d_parent
!= p
; p
= p
->d_parent
) {
1491 if (p
->d_parent
== p1
) {
1492 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1493 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1498 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1499 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1503 void unlock_rename(struct dentry
*p1
, struct dentry
*p2
)
1505 mutex_unlock(&p1
->d_inode
->i_mutex
);
1507 mutex_unlock(&p2
->d_inode
->i_mutex
);
1508 mutex_unlock(&p1
->d_inode
->i_sb
->s_vfs_rename_mutex
);
1512 int vfs_create(struct inode
*dir
, struct dentry
*dentry
, int mode
,
1513 struct nameidata
*nd
)
1515 int error
= may_create(dir
, dentry
);
1520 if (!dir
->i_op
|| !dir
->i_op
->create
)
1521 return -EACCES
; /* shouldn't it be ENOSYS? */
1524 error
= security_inode_create(dir
, dentry
, mode
);
1528 error
= dir
->i_op
->create(dir
, dentry
, mode
, nd
);
1530 fsnotify_create(dir
, dentry
);
1534 int may_open(struct nameidata
*nd
, int acc_mode
, int flag
)
1536 struct dentry
*dentry
= nd
->path
.dentry
;
1537 struct inode
*inode
= dentry
->d_inode
;
1543 if (S_ISLNK(inode
->i_mode
))
1546 if (S_ISDIR(inode
->i_mode
) && (acc_mode
& MAY_WRITE
))
1550 * FIFO's, sockets and device files are special: they don't
1551 * actually live on the filesystem itself, and as such you
1552 * can write to them even if the filesystem is read-only.
1554 if (S_ISFIFO(inode
->i_mode
) || S_ISSOCK(inode
->i_mode
)) {
1556 } else if (S_ISBLK(inode
->i_mode
) || S_ISCHR(inode
->i_mode
)) {
1557 if (nd
->path
.mnt
->mnt_flags
& MNT_NODEV
)
1563 error
= vfs_permission(nd
, acc_mode
);
1567 * An append-only file must be opened in append mode for writing.
1569 if (IS_APPEND(inode
)) {
1570 if ((flag
& FMODE_WRITE
) && !(flag
& O_APPEND
))
1576 /* O_NOATIME can only be set by the owner or superuser */
1577 if (flag
& O_NOATIME
)
1578 if (!is_owner_or_cap(inode
))
1582 * Ensure there are no outstanding leases on the file.
1584 error
= break_lease(inode
, flag
);
1588 if (flag
& O_TRUNC
) {
1589 error
= get_write_access(inode
);
1594 * Refuse to truncate files with mandatory locks held on them.
1596 error
= locks_verify_locked(inode
);
1600 error
= do_truncate(dentry
, 0,
1601 ATTR_MTIME
|ATTR_CTIME
|ATTR_OPEN
,
1604 put_write_access(inode
);
1608 if (flag
& FMODE_WRITE
)
1615 * Be careful about ever adding any more callers of this
1616 * function. Its flags must be in the namei format, not
1617 * what get passed to sys_open().
1619 static int __open_namei_create(struct nameidata
*nd
, struct path
*path
,
1623 struct dentry
*dir
= nd
->path
.dentry
;
1625 if (!IS_POSIXACL(dir
->d_inode
))
1626 mode
&= ~current
->fs
->umask
;
1627 error
= vfs_create(dir
->d_inode
, path
->dentry
, mode
, nd
);
1628 mutex_unlock(&dir
->d_inode
->i_mutex
);
1629 dput(nd
->path
.dentry
);
1630 nd
->path
.dentry
= path
->dentry
;
1633 /* Don't check for write permission, don't truncate */
1634 return may_open(nd
, 0, flag
& ~O_TRUNC
);
1638 * Note that while the flag value (low two bits) for sys_open means:
1643 * it is changed into
1644 * 00 - no permissions needed
1645 * 01 - read-permission
1646 * 10 - write-permission
1648 * for the internal routines (ie open_namei()/follow_link() etc)
1649 * This is more logical, and also allows the 00 "no perm needed"
1650 * to be used for symlinks (where the permissions are checked
1654 static inline int open_to_namei_flags(int flag
)
1656 if ((flag
+1) & O_ACCMODE
)
1661 static int open_will_write_to_fs(int flag
, struct inode
*inode
)
1664 * We'll never write to the fs underlying
1667 if (special_file(inode
->i_mode
))
1669 return (flag
& O_TRUNC
);
1673 * Note that the low bits of the passed in "open_flag"
1674 * are not the same as in the local variable "flag". See
1675 * open_to_namei_flags() for more details.
1677 struct file
*do_filp_open(int dfd
, const char *pathname
,
1678 int open_flag
, int mode
)
1681 struct nameidata nd
;
1682 int acc_mode
, error
;
1687 int flag
= open_to_namei_flags(open_flag
);
1689 acc_mode
= MAY_OPEN
| ACC_MODE(flag
);
1691 /* O_TRUNC implies we need access checks for write permissions */
1693 acc_mode
|= MAY_WRITE
;
1695 /* Allow the LSM permission hook to distinguish append
1696 access from general write access. */
1697 if (flag
& O_APPEND
)
1698 acc_mode
|= MAY_APPEND
;
1701 * The simplest case - just a plain lookup.
1703 if (!(flag
& O_CREAT
)) {
1704 error
= path_lookup_open(dfd
, pathname
, lookup_flags(flag
),
1707 return ERR_PTR(error
);
1712 * Create - we need to know the parent.
1714 error
= path_lookup_create(dfd
, pathname
, LOOKUP_PARENT
,
1717 return ERR_PTR(error
);
1720 * We have the parent and last component. First of all, check
1721 * that we are not asked to creat(2) an obvious directory - that
1725 if (nd
.last_type
!= LAST_NORM
|| nd
.last
.name
[nd
.last
.len
])
1728 dir
= nd
.path
.dentry
;
1729 nd
.flags
&= ~LOOKUP_PARENT
;
1730 mutex_lock(&dir
->d_inode
->i_mutex
);
1731 path
.dentry
= lookup_hash(&nd
);
1732 path
.mnt
= nd
.path
.mnt
;
1735 error
= PTR_ERR(path
.dentry
);
1736 if (IS_ERR(path
.dentry
)) {
1737 mutex_unlock(&dir
->d_inode
->i_mutex
);
1741 if (IS_ERR(nd
.intent
.open
.file
)) {
1742 error
= PTR_ERR(nd
.intent
.open
.file
);
1743 goto exit_mutex_unlock
;
1746 /* Negative dentry, just create the file */
1747 if (!path
.dentry
->d_inode
) {
1749 * This write is needed to ensure that a
1750 * ro->rw transition does not occur between
1751 * the time when the file is created and when
1752 * a permanent write count is taken through
1753 * the 'struct file' in nameidata_to_filp().
1755 error
= mnt_want_write(nd
.path
.mnt
);
1757 goto exit_mutex_unlock
;
1758 error
= __open_namei_create(&nd
, &path
, flag
, mode
);
1760 mnt_drop_write(nd
.path
.mnt
);
1763 filp
= nameidata_to_filp(&nd
, open_flag
);
1764 mnt_drop_write(nd
.path
.mnt
);
1769 * It already exists.
1771 mutex_unlock(&dir
->d_inode
->i_mutex
);
1772 audit_inode(pathname
, path
.dentry
);
1778 if (__follow_mount(&path
)) {
1780 if (flag
& O_NOFOLLOW
)
1785 if (!path
.dentry
->d_inode
)
1787 if (path
.dentry
->d_inode
->i_op
&& path
.dentry
->d_inode
->i_op
->follow_link
)
1790 path_to_nameidata(&path
, &nd
);
1792 if (path
.dentry
->d_inode
&& S_ISDIR(path
.dentry
->d_inode
->i_mode
))
1797 * 1. may_open() truncates a file
1798 * 2. a rw->ro mount transition occurs
1799 * 3. nameidata_to_filp() fails due to
1801 * That would be inconsistent, and should
1802 * be avoided. Taking this mnt write here
1803 * ensures that (2) can not occur.
1805 will_write
= open_will_write_to_fs(flag
, nd
.path
.dentry
->d_inode
);
1807 error
= mnt_want_write(nd
.path
.mnt
);
1811 error
= may_open(&nd
, acc_mode
, flag
);
1814 mnt_drop_write(nd
.path
.mnt
);
1817 filp
= nameidata_to_filp(&nd
, open_flag
);
1819 * It is now safe to drop the mnt write
1820 * because the filp has had a write taken
1824 mnt_drop_write(nd
.path
.mnt
);
1828 mutex_unlock(&dir
->d_inode
->i_mutex
);
1830 path_put_conditional(&path
, &nd
);
1832 if (!IS_ERR(nd
.intent
.open
.file
))
1833 release_open_intent(&nd
);
1835 return ERR_PTR(error
);
1839 if (flag
& O_NOFOLLOW
)
1842 * This is subtle. Instead of calling do_follow_link() we do the
1843 * thing by hands. The reason is that this way we have zero link_count
1844 * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT.
1845 * After that we have the parent and last component, i.e.
1846 * we are in the same situation as after the first path_walk().
1847 * Well, almost - if the last component is normal we get its copy
1848 * stored in nd->last.name and we will have to putname() it when we
1849 * are done. Procfs-like symlinks just set LAST_BIND.
1851 nd
.flags
|= LOOKUP_PARENT
;
1852 error
= security_inode_follow_link(path
.dentry
, &nd
);
1855 error
= __do_follow_link(&path
, &nd
);
1857 /* Does someone understand code flow here? Or it is only
1858 * me so stupid? Anathema to whoever designed this non-sense
1859 * with "intent.open".
1861 release_open_intent(&nd
);
1862 return ERR_PTR(error
);
1864 nd
.flags
&= ~LOOKUP_PARENT
;
1865 if (nd
.last_type
== LAST_BIND
)
1868 if (nd
.last_type
!= LAST_NORM
)
1870 if (nd
.last
.name
[nd
.last
.len
]) {
1871 __putname(nd
.last
.name
);
1876 __putname(nd
.last
.name
);
1879 dir
= nd
.path
.dentry
;
1880 mutex_lock(&dir
->d_inode
->i_mutex
);
1881 path
.dentry
= lookup_hash(&nd
);
1882 path
.mnt
= nd
.path
.mnt
;
1883 __putname(nd
.last
.name
);
1888 * filp_open - open file and return file pointer
1890 * @filename: path to open
1891 * @flags: open flags as per the open(2) second argument
1892 * @mode: mode for the new file if O_CREAT is set, else ignored
1894 * This is the helper to open a file from kernelspace if you really
1895 * have to. But in generally you should not do this, so please move
1896 * along, nothing to see here..
1898 struct file
*filp_open(const char *filename
, int flags
, int mode
)
1900 return do_filp_open(AT_FDCWD
, filename
, flags
, mode
);
1902 EXPORT_SYMBOL(filp_open
);
1905 * lookup_create - lookup a dentry, creating it if it doesn't exist
1906 * @nd: nameidata info
1907 * @is_dir: directory flag
1909 * Simple function to lookup and return a dentry and create it
1910 * if it doesn't exist. Is SMP-safe.
1912 * Returns with nd->path.dentry->d_inode->i_mutex locked.
1914 struct dentry
*lookup_create(struct nameidata
*nd
, int is_dir
)
1916 struct dentry
*dentry
= ERR_PTR(-EEXIST
);
1918 mutex_lock_nested(&nd
->path
.dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1920 * Yucky last component or no last component at all?
1921 * (foo/., foo/.., /////)
1923 if (nd
->last_type
!= LAST_NORM
)
1925 nd
->flags
&= ~LOOKUP_PARENT
;
1926 nd
->flags
|= LOOKUP_CREATE
;
1927 nd
->intent
.open
.flags
= O_EXCL
;
1930 * Do the final lookup.
1932 dentry
= lookup_hash(nd
);
1936 if (dentry
->d_inode
)
1939 * Special case - lookup gave negative, but... we had foo/bar/
1940 * From the vfs_mknod() POV we just have a negative dentry -
1941 * all is fine. Let's be bastards - you had / on the end, you've
1942 * been asking for (non-existent) directory. -ENOENT for you.
1944 if (unlikely(!is_dir
&& nd
->last
.name
[nd
->last
.len
])) {
1946 dentry
= ERR_PTR(-ENOENT
);
1951 dentry
= ERR_PTR(-EEXIST
);
1955 EXPORT_SYMBOL_GPL(lookup_create
);
1957 int vfs_mknod(struct inode
*dir
, struct dentry
*dentry
, int mode
, dev_t dev
)
1959 int error
= may_create(dir
, dentry
);
1964 if ((S_ISCHR(mode
) || S_ISBLK(mode
)) && !capable(CAP_MKNOD
))
1967 if (!dir
->i_op
|| !dir
->i_op
->mknod
)
1970 error
= devcgroup_inode_mknod(mode
, dev
);
1974 error
= security_inode_mknod(dir
, dentry
, mode
, dev
);
1979 error
= dir
->i_op
->mknod(dir
, dentry
, mode
, dev
);
1981 fsnotify_create(dir
, dentry
);
1985 static int may_mknod(mode_t mode
)
1987 switch (mode
& S_IFMT
) {
1993 case 0: /* zero mode translates to S_IFREG */
2002 asmlinkage
long sys_mknodat(int dfd
, const char __user
*filename
, int mode
,
2007 struct dentry
*dentry
;
2008 struct nameidata nd
;
2013 error
= user_path_parent(dfd
, filename
, &nd
, &tmp
);
2017 dentry
= lookup_create(&nd
, 0);
2018 if (IS_ERR(dentry
)) {
2019 error
= PTR_ERR(dentry
);
2022 if (!IS_POSIXACL(nd
.path
.dentry
->d_inode
))
2023 mode
&= ~current
->fs
->umask
;
2024 error
= may_mknod(mode
);
2027 error
= mnt_want_write(nd
.path
.mnt
);
2030 switch (mode
& S_IFMT
) {
2031 case 0: case S_IFREG
:
2032 error
= vfs_create(nd
.path
.dentry
->d_inode
,dentry
,mode
,&nd
);
2034 case S_IFCHR
: case S_IFBLK
:
2035 error
= vfs_mknod(nd
.path
.dentry
->d_inode
,dentry
,mode
,
2036 new_decode_dev(dev
));
2038 case S_IFIFO
: case S_IFSOCK
:
2039 error
= vfs_mknod(nd
.path
.dentry
->d_inode
,dentry
,mode
,0);
2042 mnt_drop_write(nd
.path
.mnt
);
2046 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2053 asmlinkage
long sys_mknod(const char __user
*filename
, int mode
, unsigned dev
)
2055 return sys_mknodat(AT_FDCWD
, filename
, mode
, dev
);
2058 int vfs_mkdir(struct inode
*dir
, struct dentry
*dentry
, int mode
)
2060 int error
= may_create(dir
, dentry
);
2065 if (!dir
->i_op
|| !dir
->i_op
->mkdir
)
2068 mode
&= (S_IRWXUGO
|S_ISVTX
);
2069 error
= security_inode_mkdir(dir
, dentry
, mode
);
2074 error
= dir
->i_op
->mkdir(dir
, dentry
, mode
);
2076 fsnotify_mkdir(dir
, dentry
);
2080 asmlinkage
long sys_mkdirat(int dfd
, const char __user
*pathname
, int mode
)
2084 struct dentry
*dentry
;
2085 struct nameidata nd
;
2087 error
= user_path_parent(dfd
, pathname
, &nd
, &tmp
);
2091 dentry
= lookup_create(&nd
, 1);
2092 error
= PTR_ERR(dentry
);
2096 if (!IS_POSIXACL(nd
.path
.dentry
->d_inode
))
2097 mode
&= ~current
->fs
->umask
;
2098 error
= mnt_want_write(nd
.path
.mnt
);
2101 error
= vfs_mkdir(nd
.path
.dentry
->d_inode
, dentry
, mode
);
2102 mnt_drop_write(nd
.path
.mnt
);
2106 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2113 asmlinkage
long sys_mkdir(const char __user
*pathname
, int mode
)
2115 return sys_mkdirat(AT_FDCWD
, pathname
, mode
);
2119 * We try to drop the dentry early: we should have
2120 * a usage count of 2 if we're the only user of this
2121 * dentry, and if that is true (possibly after pruning
2122 * the dcache), then we drop the dentry now.
2124 * A low-level filesystem can, if it choses, legally
2127 * if (!d_unhashed(dentry))
2130 * if it cannot handle the case of removing a directory
2131 * that is still in use by something else..
2133 void dentry_unhash(struct dentry
*dentry
)
2136 shrink_dcache_parent(dentry
);
2137 spin_lock(&dcache_lock
);
2138 spin_lock(&dentry
->d_lock
);
2139 if (atomic_read(&dentry
->d_count
) == 2)
2141 spin_unlock(&dentry
->d_lock
);
2142 spin_unlock(&dcache_lock
);
2145 int vfs_rmdir(struct inode
*dir
, struct dentry
*dentry
)
2147 int error
= may_delete(dir
, dentry
, 1);
2152 if (!dir
->i_op
|| !dir
->i_op
->rmdir
)
2157 mutex_lock(&dentry
->d_inode
->i_mutex
);
2158 dentry_unhash(dentry
);
2159 if (d_mountpoint(dentry
))
2162 error
= security_inode_rmdir(dir
, dentry
);
2164 error
= dir
->i_op
->rmdir(dir
, dentry
);
2166 dentry
->d_inode
->i_flags
|= S_DEAD
;
2169 mutex_unlock(&dentry
->d_inode
->i_mutex
);
2178 static long do_rmdir(int dfd
, const char __user
*pathname
)
2182 struct dentry
*dentry
;
2183 struct nameidata nd
;
2185 error
= user_path_parent(dfd
, pathname
, &nd
, &name
);
2189 switch(nd
.last_type
) {
2200 mutex_lock_nested(&nd
.path
.dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
2201 dentry
= lookup_hash(&nd
);
2202 error
= PTR_ERR(dentry
);
2205 error
= mnt_want_write(nd
.path
.mnt
);
2208 error
= vfs_rmdir(nd
.path
.dentry
->d_inode
, dentry
);
2209 mnt_drop_write(nd
.path
.mnt
);
2213 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2220 asmlinkage
long sys_rmdir(const char __user
*pathname
)
2222 return do_rmdir(AT_FDCWD
, pathname
);
2225 int vfs_unlink(struct inode
*dir
, struct dentry
*dentry
)
2227 int error
= may_delete(dir
, dentry
, 0);
2232 if (!dir
->i_op
|| !dir
->i_op
->unlink
)
2237 mutex_lock(&dentry
->d_inode
->i_mutex
);
2238 if (d_mountpoint(dentry
))
2241 error
= security_inode_unlink(dir
, dentry
);
2243 error
= dir
->i_op
->unlink(dir
, dentry
);
2245 mutex_unlock(&dentry
->d_inode
->i_mutex
);
2247 /* We don't d_delete() NFS sillyrenamed files--they still exist. */
2248 if (!error
&& !(dentry
->d_flags
& DCACHE_NFSFS_RENAMED
)) {
2249 fsnotify_link_count(dentry
->d_inode
);
2257 * Make sure that the actual truncation of the file will occur outside its
2258 * directory's i_mutex. Truncate can take a long time if there is a lot of
2259 * writeout happening, and we don't want to prevent access to the directory
2260 * while waiting on the I/O.
2262 static long do_unlinkat(int dfd
, const char __user
*pathname
)
2266 struct dentry
*dentry
;
2267 struct nameidata nd
;
2268 struct inode
*inode
= NULL
;
2270 error
= user_path_parent(dfd
, pathname
, &nd
, &name
);
2275 if (nd
.last_type
!= LAST_NORM
)
2277 mutex_lock_nested(&nd
.path
.dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
2278 dentry
= lookup_hash(&nd
);
2279 error
= PTR_ERR(dentry
);
2280 if (!IS_ERR(dentry
)) {
2281 /* Why not before? Because we want correct error value */
2282 if (nd
.last
.name
[nd
.last
.len
])
2284 inode
= dentry
->d_inode
;
2286 atomic_inc(&inode
->i_count
);
2287 error
= mnt_want_write(nd
.path
.mnt
);
2290 error
= vfs_unlink(nd
.path
.dentry
->d_inode
, dentry
);
2291 mnt_drop_write(nd
.path
.mnt
);
2295 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2297 iput(inode
); /* truncate the inode here */
2304 error
= !dentry
->d_inode
? -ENOENT
:
2305 S_ISDIR(dentry
->d_inode
->i_mode
) ? -EISDIR
: -ENOTDIR
;
2309 asmlinkage
long sys_unlinkat(int dfd
, const char __user
*pathname
, int flag
)
2311 if ((flag
& ~AT_REMOVEDIR
) != 0)
2314 if (flag
& AT_REMOVEDIR
)
2315 return do_rmdir(dfd
, pathname
);
2317 return do_unlinkat(dfd
, pathname
);
2320 asmlinkage
long sys_unlink(const char __user
*pathname
)
2322 return do_unlinkat(AT_FDCWD
, pathname
);
2325 int vfs_symlink(struct inode
*dir
, struct dentry
*dentry
, const char *oldname
)
2327 int error
= may_create(dir
, dentry
);
2332 if (!dir
->i_op
|| !dir
->i_op
->symlink
)
2335 error
= security_inode_symlink(dir
, dentry
, oldname
);
2340 error
= dir
->i_op
->symlink(dir
, dentry
, oldname
);
2342 fsnotify_create(dir
, dentry
);
2346 asmlinkage
long sys_symlinkat(const char __user
*oldname
,
2347 int newdfd
, const char __user
*newname
)
2352 struct dentry
*dentry
;
2353 struct nameidata nd
;
2355 from
= getname(oldname
);
2357 return PTR_ERR(from
);
2359 error
= user_path_parent(newdfd
, newname
, &nd
, &to
);
2363 dentry
= lookup_create(&nd
, 0);
2364 error
= PTR_ERR(dentry
);
2368 error
= mnt_want_write(nd
.path
.mnt
);
2371 error
= vfs_symlink(nd
.path
.dentry
->d_inode
, dentry
, from
);
2372 mnt_drop_write(nd
.path
.mnt
);
2376 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2384 asmlinkage
long sys_symlink(const char __user
*oldname
, const char __user
*newname
)
2386 return sys_symlinkat(oldname
, AT_FDCWD
, newname
);
2389 int vfs_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*new_dentry
)
2391 struct inode
*inode
= old_dentry
->d_inode
;
2397 error
= may_create(dir
, new_dentry
);
2401 if (dir
->i_sb
!= inode
->i_sb
)
2405 * A link to an append-only or immutable file cannot be created.
2407 if (IS_APPEND(inode
) || IS_IMMUTABLE(inode
))
2409 if (!dir
->i_op
|| !dir
->i_op
->link
)
2411 if (S_ISDIR(inode
->i_mode
))
2414 error
= security_inode_link(old_dentry
, dir
, new_dentry
);
2418 mutex_lock(&inode
->i_mutex
);
2420 error
= dir
->i_op
->link(old_dentry
, dir
, new_dentry
);
2421 mutex_unlock(&inode
->i_mutex
);
2423 fsnotify_link(dir
, inode
, new_dentry
);
2428 * Hardlinks are often used in delicate situations. We avoid
2429 * security-related surprises by not following symlinks on the
2432 * We don't follow them on the oldname either to be compatible
2433 * with linux 2.0, and to avoid hard-linking to directories
2434 * and other special files. --ADM
2436 asmlinkage
long sys_linkat(int olddfd
, const char __user
*oldname
,
2437 int newdfd
, const char __user
*newname
,
2440 struct dentry
*new_dentry
;
2441 struct nameidata nd
;
2442 struct path old_path
;
2446 if ((flags
& ~AT_SYMLINK_FOLLOW
) != 0)
2449 error
= user_path_at(olddfd
, oldname
,
2450 flags
& AT_SYMLINK_FOLLOW
? LOOKUP_FOLLOW
: 0,
2455 error
= user_path_parent(newdfd
, newname
, &nd
, &to
);
2459 if (old_path
.mnt
!= nd
.path
.mnt
)
2461 new_dentry
= lookup_create(&nd
, 0);
2462 error
= PTR_ERR(new_dentry
);
2463 if (IS_ERR(new_dentry
))
2465 error
= mnt_want_write(nd
.path
.mnt
);
2468 error
= vfs_link(old_path
.dentry
, nd
.path
.dentry
->d_inode
, new_dentry
);
2469 mnt_drop_write(nd
.path
.mnt
);
2473 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2478 path_put(&old_path
);
2483 asmlinkage
long sys_link(const char __user
*oldname
, const char __user
*newname
)
2485 return sys_linkat(AT_FDCWD
, oldname
, AT_FDCWD
, newname
, 0);
2489 * The worst of all namespace operations - renaming directory. "Perverted"
2490 * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
2492 * a) we can get into loop creation. Check is done in is_subdir().
2493 * b) race potential - two innocent renames can create a loop together.
2494 * That's where 4.4 screws up. Current fix: serialization on
2495 * sb->s_vfs_rename_mutex. We might be more accurate, but that's another
2497 * c) we have to lock _three_ objects - parents and victim (if it exists).
2498 * And that - after we got ->i_mutex on parents (until then we don't know
2499 * whether the target exists). Solution: try to be smart with locking
2500 * order for inodes. We rely on the fact that tree topology may change
2501 * only under ->s_vfs_rename_mutex _and_ that parent of the object we
2502 * move will be locked. Thus we can rank directories by the tree
2503 * (ancestors first) and rank all non-directories after them.
2504 * That works since everybody except rename does "lock parent, lookup,
2505 * lock child" and rename is under ->s_vfs_rename_mutex.
2506 * HOWEVER, it relies on the assumption that any object with ->lookup()
2507 * has no more than 1 dentry. If "hybrid" objects will ever appear,
2508 * we'd better make sure that there's no link(2) for them.
2509 * d) some filesystems don't support opened-but-unlinked directories,
2510 * either because of layout or because they are not ready to deal with
2511 * all cases correctly. The latter will be fixed (taking this sort of
2512 * stuff into VFS), but the former is not going away. Solution: the same
2513 * trick as in rmdir().
2514 * e) conversion from fhandle to dentry may come in the wrong moment - when
2515 * we are removing the target. Solution: we will have to grab ->i_mutex
2516 * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on
2517 * ->i_mutex on parents, which works but leads to some truely excessive
2520 static int vfs_rename_dir(struct inode
*old_dir
, struct dentry
*old_dentry
,
2521 struct inode
*new_dir
, struct dentry
*new_dentry
)
2524 struct inode
*target
;
2527 * If we are going to change the parent - check write permissions,
2528 * we'll need to flip '..'.
2530 if (new_dir
!= old_dir
) {
2531 error
= inode_permission(old_dentry
->d_inode
, MAY_WRITE
);
2536 error
= security_inode_rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2540 target
= new_dentry
->d_inode
;
2542 mutex_lock(&target
->i_mutex
);
2543 dentry_unhash(new_dentry
);
2545 if (d_mountpoint(old_dentry
)||d_mountpoint(new_dentry
))
2548 error
= old_dir
->i_op
->rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2551 target
->i_flags
|= S_DEAD
;
2552 mutex_unlock(&target
->i_mutex
);
2553 if (d_unhashed(new_dentry
))
2554 d_rehash(new_dentry
);
2558 if (!(old_dir
->i_sb
->s_type
->fs_flags
& FS_RENAME_DOES_D_MOVE
))
2559 d_move(old_dentry
,new_dentry
);
2563 static int vfs_rename_other(struct inode
*old_dir
, struct dentry
*old_dentry
,
2564 struct inode
*new_dir
, struct dentry
*new_dentry
)
2566 struct inode
*target
;
2569 error
= security_inode_rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2574 target
= new_dentry
->d_inode
;
2576 mutex_lock(&target
->i_mutex
);
2577 if (d_mountpoint(old_dentry
)||d_mountpoint(new_dentry
))
2580 error
= old_dir
->i_op
->rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2582 if (!(old_dir
->i_sb
->s_type
->fs_flags
& FS_RENAME_DOES_D_MOVE
))
2583 d_move(old_dentry
, new_dentry
);
2586 mutex_unlock(&target
->i_mutex
);
2591 int vfs_rename(struct inode
*old_dir
, struct dentry
*old_dentry
,
2592 struct inode
*new_dir
, struct dentry
*new_dentry
)
2595 int is_dir
= S_ISDIR(old_dentry
->d_inode
->i_mode
);
2596 const char *old_name
;
2598 if (old_dentry
->d_inode
== new_dentry
->d_inode
)
2601 error
= may_delete(old_dir
, old_dentry
, is_dir
);
2605 if (!new_dentry
->d_inode
)
2606 error
= may_create(new_dir
, new_dentry
);
2608 error
= may_delete(new_dir
, new_dentry
, is_dir
);
2612 if (!old_dir
->i_op
|| !old_dir
->i_op
->rename
)
2615 DQUOT_INIT(old_dir
);
2616 DQUOT_INIT(new_dir
);
2618 old_name
= fsnotify_oldname_init(old_dentry
->d_name
.name
);
2621 error
= vfs_rename_dir(old_dir
,old_dentry
,new_dir
,new_dentry
);
2623 error
= vfs_rename_other(old_dir
,old_dentry
,new_dir
,new_dentry
);
2625 const char *new_name
= old_dentry
->d_name
.name
;
2626 fsnotify_move(old_dir
, new_dir
, old_name
, new_name
, is_dir
,
2627 new_dentry
->d_inode
, old_dentry
);
2629 fsnotify_oldname_free(old_name
);
2634 asmlinkage
long sys_renameat(int olddfd
, const char __user
*oldname
,
2635 int newdfd
, const char __user
*newname
)
2637 struct dentry
*old_dir
, *new_dir
;
2638 struct dentry
*old_dentry
, *new_dentry
;
2639 struct dentry
*trap
;
2640 struct nameidata oldnd
, newnd
;
2645 error
= user_path_parent(olddfd
, oldname
, &oldnd
, &from
);
2649 error
= user_path_parent(newdfd
, newname
, &newnd
, &to
);
2654 if (oldnd
.path
.mnt
!= newnd
.path
.mnt
)
2657 old_dir
= oldnd
.path
.dentry
;
2659 if (oldnd
.last_type
!= LAST_NORM
)
2662 new_dir
= newnd
.path
.dentry
;
2663 if (newnd
.last_type
!= LAST_NORM
)
2666 trap
= lock_rename(new_dir
, old_dir
);
2668 old_dentry
= lookup_hash(&oldnd
);
2669 error
= PTR_ERR(old_dentry
);
2670 if (IS_ERR(old_dentry
))
2672 /* source must exist */
2674 if (!old_dentry
->d_inode
)
2676 /* unless the source is a directory trailing slashes give -ENOTDIR */
2677 if (!S_ISDIR(old_dentry
->d_inode
->i_mode
)) {
2679 if (oldnd
.last
.name
[oldnd
.last
.len
])
2681 if (newnd
.last
.name
[newnd
.last
.len
])
2684 /* source should not be ancestor of target */
2686 if (old_dentry
== trap
)
2688 new_dentry
= lookup_hash(&newnd
);
2689 error
= PTR_ERR(new_dentry
);
2690 if (IS_ERR(new_dentry
))
2692 /* target should not be an ancestor of source */
2694 if (new_dentry
== trap
)
2697 error
= mnt_want_write(oldnd
.path
.mnt
);
2700 error
= vfs_rename(old_dir
->d_inode
, old_dentry
,
2701 new_dir
->d_inode
, new_dentry
);
2702 mnt_drop_write(oldnd
.path
.mnt
);
2708 unlock_rename(new_dir
, old_dir
);
2710 path_put(&newnd
.path
);
2713 path_put(&oldnd
.path
);
2719 asmlinkage
long sys_rename(const char __user
*oldname
, const char __user
*newname
)
2721 return sys_renameat(AT_FDCWD
, oldname
, AT_FDCWD
, newname
);
2724 int vfs_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
, const char *link
)
2728 len
= PTR_ERR(link
);
2733 if (len
> (unsigned) buflen
)
2735 if (copy_to_user(buffer
, link
, len
))
2742 * A helper for ->readlink(). This should be used *ONLY* for symlinks that
2743 * have ->follow_link() touching nd only in nd_set_link(). Using (or not
2744 * using) it for any given inode is up to filesystem.
2746 int generic_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
)
2748 struct nameidata nd
;
2753 cookie
= dentry
->d_inode
->i_op
->follow_link(dentry
, &nd
);
2755 return PTR_ERR(cookie
);
2757 res
= vfs_readlink(dentry
, buffer
, buflen
, nd_get_link(&nd
));
2758 if (dentry
->d_inode
->i_op
->put_link
)
2759 dentry
->d_inode
->i_op
->put_link(dentry
, &nd
, cookie
);
2763 int vfs_follow_link(struct nameidata
*nd
, const char *link
)
2765 return __vfs_follow_link(nd
, link
);
2768 /* get the link contents into pagecache */
2769 static char *page_getlink(struct dentry
* dentry
, struct page
**ppage
)
2772 struct address_space
*mapping
= dentry
->d_inode
->i_mapping
;
2773 page
= read_mapping_page(mapping
, 0, NULL
);
2780 int page_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
)
2782 struct page
*page
= NULL
;
2783 char *s
= page_getlink(dentry
, &page
);
2784 int res
= vfs_readlink(dentry
,buffer
,buflen
,s
);
2787 page_cache_release(page
);
2792 void *page_follow_link_light(struct dentry
*dentry
, struct nameidata
*nd
)
2794 struct page
*page
= NULL
;
2795 nd_set_link(nd
, page_getlink(dentry
, &page
));
2799 void page_put_link(struct dentry
*dentry
, struct nameidata
*nd
, void *cookie
)
2801 struct page
*page
= cookie
;
2805 page_cache_release(page
);
2809 int __page_symlink(struct inode
*inode
, const char *symname
, int len
,
2812 struct address_space
*mapping
= inode
->i_mapping
;
2819 err
= pagecache_write_begin(NULL
, mapping
, 0, len
-1,
2820 AOP_FLAG_UNINTERRUPTIBLE
, &page
, &fsdata
);
2824 kaddr
= kmap_atomic(page
, KM_USER0
);
2825 memcpy(kaddr
, symname
, len
-1);
2826 kunmap_atomic(kaddr
, KM_USER0
);
2828 err
= pagecache_write_end(NULL
, mapping
, 0, len
-1, len
-1,
2835 mark_inode_dirty(inode
);
2841 int page_symlink(struct inode
*inode
, const char *symname
, int len
)
2843 return __page_symlink(inode
, symname
, len
,
2844 mapping_gfp_mask(inode
->i_mapping
));
2847 const struct inode_operations page_symlink_inode_operations
= {
2848 .readlink
= generic_readlink
,
2849 .follow_link
= page_follow_link_light
,
2850 .put_link
= page_put_link
,
2853 EXPORT_SYMBOL(user_path_at
);
2854 EXPORT_SYMBOL(follow_down
);
2855 EXPORT_SYMBOL(follow_up
);
2856 EXPORT_SYMBOL(get_write_access
); /* binfmt_aout */
2857 EXPORT_SYMBOL(getname
);
2858 EXPORT_SYMBOL(lock_rename
);
2859 EXPORT_SYMBOL(lookup_one_len
);
2860 EXPORT_SYMBOL(page_follow_link_light
);
2861 EXPORT_SYMBOL(page_put_link
);
2862 EXPORT_SYMBOL(page_readlink
);
2863 EXPORT_SYMBOL(__page_symlink
);
2864 EXPORT_SYMBOL(page_symlink
);
2865 EXPORT_SYMBOL(page_symlink_inode_operations
);
2866 EXPORT_SYMBOL(path_lookup
);
2867 EXPORT_SYMBOL(kern_path
);
2868 EXPORT_SYMBOL(vfs_path_lookup
);
2869 EXPORT_SYMBOL(inode_permission
);
2870 EXPORT_SYMBOL(vfs_permission
);
2871 EXPORT_SYMBOL(file_permission
);
2872 EXPORT_SYMBOL(unlock_rename
);
2873 EXPORT_SYMBOL(vfs_create
);
2874 EXPORT_SYMBOL(vfs_follow_link
);
2875 EXPORT_SYMBOL(vfs_link
);
2876 EXPORT_SYMBOL(vfs_mkdir
);
2877 EXPORT_SYMBOL(vfs_mknod
);
2878 EXPORT_SYMBOL(generic_permission
);
2879 EXPORT_SYMBOL(vfs_readlink
);
2880 EXPORT_SYMBOL(vfs_rename
);
2881 EXPORT_SYMBOL(vfs_rmdir
);
2882 EXPORT_SYMBOL(vfs_symlink
);
2883 EXPORT_SYMBOL(vfs_unlink
);
2884 EXPORT_SYMBOL(dentry_unhash
);
2885 EXPORT_SYMBOL(generic_readlink
);