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/ima.h>
28 #include <linux/syscalls.h>
29 #include <linux/mount.h>
30 #include <linux/audit.h>
31 #include <linux/capability.h>
32 #include <linux/file.h>
33 #include <linux/fcntl.h>
34 #include <linux/device_cgroup.h>
35 #include <linux/fs_struct.h>
36 #include <asm/uaccess.h>
38 #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
40 /* [Feb-1997 T. Schoebel-Theuer]
41 * Fundamental changes in the pathname lookup mechanisms (namei)
42 * were necessary because of omirr. The reason is that omirr needs
43 * to know the _real_ pathname, not the user-supplied one, in case
44 * of symlinks (and also when transname replacements occur).
46 * The new code replaces the old recursive symlink resolution with
47 * an iterative one (in case of non-nested symlink chains). It does
48 * this with calls to <fs>_follow_link().
49 * As a side effect, dir_namei(), _namei() and follow_link() are now
50 * replaced with a single function lookup_dentry() that can handle all
51 * the special cases of the former code.
53 * With the new dcache, the pathname is stored at each inode, at least as
54 * long as the refcount of the inode is positive. As a side effect, the
55 * size of the dcache depends on the inode cache and thus is dynamic.
57 * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink
58 * resolution to correspond with current state of the code.
60 * Note that the symlink resolution is not *completely* iterative.
61 * There is still a significant amount of tail- and mid- recursion in
62 * the algorithm. Also, note that <fs>_readlink() is not used in
63 * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink()
64 * may return different results than <fs>_follow_link(). Many virtual
65 * filesystems (including /proc) exhibit this behavior.
68 /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation:
69 * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL
70 * and the name already exists in form of a symlink, try to create the new
71 * name indicated by the symlink. The old code always complained that the
72 * name already exists, due to not following the symlink even if its target
73 * is nonexistent. The new semantics affects also mknod() and link() when
74 * the name is a symlink pointing to a non-existant name.
76 * I don't know which semantics is the right one, since I have no access
77 * to standards. But I found by trial that HP-UX 9.0 has the full "new"
78 * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the
79 * "old" one. Personally, I think the new semantics is much more logical.
80 * Note that "ln old new" where "new" is a symlink pointing to a non-existing
81 * file does succeed in both HP-UX and SunOs, but not in Solaris
82 * and in the old Linux semantics.
85 /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink
86 * semantics. See the comments in "open_namei" and "do_link" below.
88 * [10-Sep-98 Alan Modra] Another symlink change.
91 /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks:
92 * inside the path - always follow.
93 * in the last component in creation/removal/renaming - never follow.
94 * if LOOKUP_FOLLOW passed - follow.
95 * if the pathname has trailing slashes - follow.
96 * otherwise - don't follow.
97 * (applied in that order).
99 * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT
100 * restored for 2.4. This is the last surviving part of old 4.2BSD bug.
101 * During the 2.4 we need to fix the userland stuff depending on it -
102 * hopefully we will be able to get rid of that wart in 2.5. So far only
103 * XEmacs seems to be relying on it...
106 * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland)
107 * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives
108 * any extra contention...
111 static int __link_path_walk(const char *name
, struct nameidata
*nd
);
113 /* In order to reduce some races, while at the same time doing additional
114 * checking and hopefully speeding things up, we copy filenames to the
115 * kernel data space before using them..
117 * POSIX.1 2.4: an empty pathname is invalid (ENOENT).
118 * PATH_MAX includes the nul terminator --RR.
120 static int do_getname(const char __user
*filename
, char *page
)
123 unsigned long len
= PATH_MAX
;
125 if (!segment_eq(get_fs(), KERNEL_DS
)) {
126 if ((unsigned long) filename
>= TASK_SIZE
)
128 if (TASK_SIZE
- (unsigned long) filename
< PATH_MAX
)
129 len
= TASK_SIZE
- (unsigned long) filename
;
132 retval
= strncpy_from_user(page
, filename
, len
);
136 return -ENAMETOOLONG
;
142 char * getname(const char __user
* filename
)
146 result
= ERR_PTR(-ENOMEM
);
149 int retval
= do_getname(filename
, tmp
);
154 result
= ERR_PTR(retval
);
157 audit_getname(result
);
161 #ifdef CONFIG_AUDITSYSCALL
162 void putname(const char *name
)
164 if (unlikely(!audit_dummy_context()))
169 EXPORT_SYMBOL(putname
);
174 * generic_permission - check for access rights on a Posix-like filesystem
175 * @inode: inode to check access rights for
176 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
177 * @check_acl: optional callback to check for Posix ACLs
179 * Used to check for read/write/execute permissions on a file.
180 * We use "fsuid" for this, letting us set arbitrary permissions
181 * for filesystem access without changing the "normal" uids which
182 * are used for other things..
184 int generic_permission(struct inode
*inode
, int mask
,
185 int (*check_acl
)(struct inode
*inode
, int mask
))
187 umode_t mode
= inode
->i_mode
;
189 mask
&= MAY_READ
| MAY_WRITE
| MAY_EXEC
;
191 if (current_fsuid() == inode
->i_uid
)
194 if (IS_POSIXACL(inode
) && (mode
& S_IRWXG
) && check_acl
) {
195 int error
= check_acl(inode
, mask
);
196 if (error
== -EACCES
)
197 goto check_capabilities
;
198 else if (error
!= -EAGAIN
)
202 if (in_group_p(inode
->i_gid
))
207 * If the DACs are ok we don't need any capability check.
209 if ((mask
& ~mode
) == 0)
214 * Read/write DACs are always overridable.
215 * Executable DACs are overridable if at least one exec bit is set.
217 if (!(mask
& MAY_EXEC
) || execute_ok(inode
))
218 if (capable(CAP_DAC_OVERRIDE
))
222 * Searching includes executable on directories, else just read.
224 if (mask
== MAY_READ
|| (S_ISDIR(inode
->i_mode
) && !(mask
& MAY_WRITE
)))
225 if (capable(CAP_DAC_READ_SEARCH
))
232 * inode_permission - check for access rights to a given inode
233 * @inode: inode to check permission on
234 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
236 * Used to check for read/write/execute permissions on an inode.
237 * We use "fsuid" for this, letting us set arbitrary permissions
238 * for filesystem access without changing the "normal" uids which
239 * are used for other things.
241 int inode_permission(struct inode
*inode
, int mask
)
245 if (mask
& MAY_WRITE
) {
246 umode_t mode
= inode
->i_mode
;
249 * Nobody gets write access to a read-only fs.
251 if (IS_RDONLY(inode
) &&
252 (S_ISREG(mode
) || S_ISDIR(mode
) || S_ISLNK(mode
)))
256 * Nobody gets write access to an immutable file.
258 if (IS_IMMUTABLE(inode
))
262 if (inode
->i_op
->permission
)
263 retval
= inode
->i_op
->permission(inode
, mask
);
265 retval
= generic_permission(inode
, mask
, NULL
);
270 retval
= devcgroup_inode_permission(inode
, mask
);
274 return security_inode_permission(inode
,
275 mask
& (MAY_READ
|MAY_WRITE
|MAY_EXEC
|MAY_APPEND
));
279 * file_permission - check for additional access rights to a given file
280 * @file: file to check access rights for
281 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
283 * Used to check for read/write/execute permissions on an already opened
287 * Do not use this function in new code. All access checks should
288 * be done using inode_permission().
290 int file_permission(struct file
*file
, int mask
)
292 return inode_permission(file
->f_path
.dentry
->d_inode
, mask
);
296 * get_write_access() gets write permission for a file.
297 * put_write_access() releases this write permission.
298 * This is used for regular files.
299 * We cannot support write (and maybe mmap read-write shared) accesses and
300 * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
301 * can have the following values:
302 * 0: no writers, no VM_DENYWRITE mappings
303 * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
304 * > 0: (i_writecount) users are writing to the file.
306 * Normally we operate on that counter with atomic_{inc,dec} and it's safe
307 * except for the cases where we don't hold i_writecount yet. Then we need to
308 * use {get,deny}_write_access() - these functions check the sign and refuse
309 * to do the change if sign is wrong. Exclusion between them is provided by
310 * the inode->i_lock spinlock.
313 int get_write_access(struct inode
* inode
)
315 spin_lock(&inode
->i_lock
);
316 if (atomic_read(&inode
->i_writecount
) < 0) {
317 spin_unlock(&inode
->i_lock
);
320 atomic_inc(&inode
->i_writecount
);
321 spin_unlock(&inode
->i_lock
);
326 int deny_write_access(struct file
* file
)
328 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
330 spin_lock(&inode
->i_lock
);
331 if (atomic_read(&inode
->i_writecount
) > 0) {
332 spin_unlock(&inode
->i_lock
);
335 atomic_dec(&inode
->i_writecount
);
336 spin_unlock(&inode
->i_lock
);
342 * path_get - get a reference to a path
343 * @path: path to get the reference to
345 * Given a path increment the reference count to the dentry and the vfsmount.
347 void path_get(struct path
*path
)
352 EXPORT_SYMBOL(path_get
);
355 * path_put - put a reference to a path
356 * @path: path to put the reference to
358 * Given a path decrement the reference count to the dentry and the vfsmount.
360 void path_put(struct path
*path
)
365 EXPORT_SYMBOL(path_put
);
368 * release_open_intent - free up open intent resources
369 * @nd: pointer to nameidata
371 void release_open_intent(struct nameidata
*nd
)
373 if (nd
->intent
.open
.file
->f_path
.dentry
== NULL
)
374 put_filp(nd
->intent
.open
.file
);
376 fput(nd
->intent
.open
.file
);
379 static inline struct dentry
*
380 do_revalidate(struct dentry
*dentry
, struct nameidata
*nd
)
382 int status
= dentry
->d_op
->d_revalidate(dentry
, nd
);
383 if (unlikely(status
<= 0)) {
385 * The dentry failed validation.
386 * If d_revalidate returned 0 attempt to invalidate
387 * the dentry otherwise d_revalidate is asking us
388 * to return a fail status.
391 if (!d_invalidate(dentry
)) {
397 dentry
= ERR_PTR(status
);
404 * Internal lookup() using the new generic dcache.
407 static struct dentry
* cached_lookup(struct dentry
* parent
, struct qstr
* name
, struct nameidata
*nd
)
409 struct dentry
* dentry
= __d_lookup(parent
, name
);
411 /* lockess __d_lookup may fail due to concurrent d_move()
412 * in some unrelated directory, so try with d_lookup
415 dentry
= d_lookup(parent
, name
);
417 if (dentry
&& dentry
->d_op
&& dentry
->d_op
->d_revalidate
)
418 dentry
= do_revalidate(dentry
, nd
);
424 * Short-cut version of permission(), for calling by
425 * path_walk(), when dcache lock is held. Combines parts
426 * of permission() and generic_permission(), and tests ONLY for
427 * MAY_EXEC permission.
429 * If appropriate, check DAC only. If not appropriate, or
430 * short-cut DAC fails, then call permission() to do more
431 * complete permission check.
433 static int exec_permission_lite(struct inode
*inode
)
435 umode_t mode
= inode
->i_mode
;
437 if (inode
->i_op
->permission
) {
438 int ret
= inode
->i_op
->permission(inode
, MAY_EXEC
);
444 if (current_fsuid() == inode
->i_uid
)
446 else if (in_group_p(inode
->i_gid
))
452 if (capable(CAP_DAC_OVERRIDE
) || capable(CAP_DAC_READ_SEARCH
))
457 return security_inode_permission(inode
, MAY_EXEC
);
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..
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..
468 static struct dentry
* real_lookup(struct dentry
* parent
, struct qstr
* name
, struct nameidata
*nd
)
470 struct dentry
* result
;
471 struct inode
*dir
= parent
->d_inode
;
473 mutex_lock(&dir
->i_mutex
);
475 * First re-do the cached lookup just in case it was created
476 * while we waited for the directory semaphore..
478 * FIXME! This could use version numbering or similar to
479 * avoid unnecessary cache lookups.
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
486 * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
488 result
= d_lookup(parent
, name
);
490 struct dentry
*dentry
;
492 /* Don't create child dentry for a dead directory. */
493 result
= ERR_PTR(-ENOENT
);
497 dentry
= d_alloc(parent
, name
);
498 result
= ERR_PTR(-ENOMEM
);
500 result
= dir
->i_op
->lookup(dir
, dentry
, nd
);
507 mutex_unlock(&dir
->i_mutex
);
512 * Uhhuh! Nasty case: the cache was re-populated while
513 * we waited on the semaphore. Need to revalidate.
515 mutex_unlock(&dir
->i_mutex
);
516 if (result
->d_op
&& result
->d_op
->d_revalidate
) {
517 result
= do_revalidate(result
, nd
);
519 result
= ERR_PTR(-ENOENT
);
525 * Wrapper to retry pathname resolution whenever the underlying
526 * file system returns an ESTALE.
528 * Retry the whole path once, forcing real lookup requests
529 * instead of relying on the dcache.
531 static __always_inline
int link_path_walk(const char *name
, struct nameidata
*nd
)
533 struct path save
= nd
->path
;
536 /* make sure the stuff we saved doesn't go away */
539 result
= __link_path_walk(name
, nd
);
540 if (result
== -ESTALE
) {
541 /* nd->path had been dropped */
544 nd
->flags
|= LOOKUP_REVAL
;
545 result
= __link_path_walk(name
, nd
);
553 static __always_inline
void set_root(struct nameidata
*nd
)
556 struct fs_struct
*fs
= current
->fs
;
557 read_lock(&fs
->lock
);
560 read_unlock(&fs
->lock
);
564 static __always_inline
int __vfs_follow_link(struct nameidata
*nd
, const char *link
)
578 res
= link_path_walk(link
, nd
);
579 if (nd
->depth
|| res
|| nd
->last_type
!=LAST_NORM
)
582 * If it is an iterative symlinks resolution in open_namei() we
583 * have to copy the last component. And all that crap because of
584 * bloody create() on broken symlinks. Furrfu...
587 if (unlikely(!name
)) {
591 strcpy(name
, nd
->last
.name
);
592 nd
->last
.name
= name
;
596 return PTR_ERR(link
);
599 static void path_put_conditional(struct path
*path
, struct nameidata
*nd
)
602 if (path
->mnt
!= nd
->path
.mnt
)
606 static inline void path_to_nameidata(struct path
*path
, struct nameidata
*nd
)
608 dput(nd
->path
.dentry
);
609 if (nd
->path
.mnt
!= path
->mnt
)
610 mntput(nd
->path
.mnt
);
611 nd
->path
.mnt
= path
->mnt
;
612 nd
->path
.dentry
= path
->dentry
;
615 static __always_inline
int __do_follow_link(struct path
*path
, struct nameidata
*nd
)
619 struct dentry
*dentry
= path
->dentry
;
621 touch_atime(path
->mnt
, dentry
);
622 nd_set_link(nd
, NULL
);
624 if (path
->mnt
!= nd
->path
.mnt
) {
625 path_to_nameidata(path
, nd
);
629 cookie
= dentry
->d_inode
->i_op
->follow_link(dentry
, nd
);
630 error
= PTR_ERR(cookie
);
631 if (!IS_ERR(cookie
)) {
632 char *s
= nd_get_link(nd
);
635 error
= __vfs_follow_link(nd
, s
);
636 if (dentry
->d_inode
->i_op
->put_link
)
637 dentry
->d_inode
->i_op
->put_link(dentry
, nd
, cookie
);
645 * This limits recursive symlink follows to 8, while
646 * limiting consecutive symlinks to 40.
648 * Without that kind of total limit, nasty chains of consecutive
649 * symlinks can cause almost arbitrarily long lookups.
651 static inline int do_follow_link(struct path
*path
, struct nameidata
*nd
)
654 if (current
->link_count
>= MAX_NESTED_LINKS
)
656 if (current
->total_link_count
>= 40)
658 BUG_ON(nd
->depth
>= MAX_NESTED_LINKS
);
660 err
= security_inode_follow_link(path
->dentry
, nd
);
663 current
->link_count
++;
664 current
->total_link_count
++;
666 err
= __do_follow_link(path
, nd
);
667 current
->link_count
--;
671 path_put_conditional(path
, nd
);
676 int follow_up(struct path
*path
)
678 struct vfsmount
*parent
;
679 struct dentry
*mountpoint
;
680 spin_lock(&vfsmount_lock
);
681 parent
= path
->mnt
->mnt_parent
;
682 if (parent
== path
->mnt
) {
683 spin_unlock(&vfsmount_lock
);
687 mountpoint
= dget(path
->mnt
->mnt_mountpoint
);
688 spin_unlock(&vfsmount_lock
);
690 path
->dentry
= mountpoint
;
696 /* no need for dcache_lock, as serialization is taken care in
699 static int __follow_mount(struct path
*path
)
702 while (d_mountpoint(path
->dentry
)) {
703 struct vfsmount
*mounted
= lookup_mnt(path
);
710 path
->dentry
= dget(mounted
->mnt_root
);
716 static void follow_mount(struct path
*path
)
718 while (d_mountpoint(path
->dentry
)) {
719 struct vfsmount
*mounted
= lookup_mnt(path
);
725 path
->dentry
= dget(mounted
->mnt_root
);
729 /* no need for dcache_lock, as serialization is taken care in
732 int follow_down(struct path
*path
)
734 struct vfsmount
*mounted
;
736 mounted
= lookup_mnt(path
);
741 path
->dentry
= dget(mounted
->mnt_root
);
747 static __always_inline
void follow_dotdot(struct nameidata
*nd
)
752 struct vfsmount
*parent
;
753 struct dentry
*old
= nd
->path
.dentry
;
755 if (nd
->path
.dentry
== nd
->root
.dentry
&&
756 nd
->path
.mnt
== nd
->root
.mnt
) {
759 spin_lock(&dcache_lock
);
760 if (nd
->path
.dentry
!= nd
->path
.mnt
->mnt_root
) {
761 nd
->path
.dentry
= dget(nd
->path
.dentry
->d_parent
);
762 spin_unlock(&dcache_lock
);
766 spin_unlock(&dcache_lock
);
767 spin_lock(&vfsmount_lock
);
768 parent
= nd
->path
.mnt
->mnt_parent
;
769 if (parent
== nd
->path
.mnt
) {
770 spin_unlock(&vfsmount_lock
);
774 nd
->path
.dentry
= dget(nd
->path
.mnt
->mnt_mountpoint
);
775 spin_unlock(&vfsmount_lock
);
777 mntput(nd
->path
.mnt
);
778 nd
->path
.mnt
= parent
;
780 follow_mount(&nd
->path
);
784 * It's more convoluted than I'd like it to be, but... it's still fairly
785 * small and for now I'd prefer to have fast path as straight as possible.
786 * It _is_ time-critical.
788 static int do_lookup(struct nameidata
*nd
, struct qstr
*name
,
791 struct vfsmount
*mnt
= nd
->path
.mnt
;
792 struct dentry
*dentry
= __d_lookup(nd
->path
.dentry
, name
);
796 if (dentry
->d_op
&& dentry
->d_op
->d_revalidate
)
797 goto need_revalidate
;
800 path
->dentry
= dentry
;
801 __follow_mount(path
);
805 dentry
= real_lookup(nd
->path
.dentry
, name
, nd
);
811 dentry
= do_revalidate(dentry
, nd
);
819 return PTR_ERR(dentry
);
824 * This is the basic name resolution function, turning a pathname into
825 * the final dentry. We expect 'base' to be positive and a directory.
827 * Returns 0 and nd will have valid dentry and mnt on success.
828 * Returns error and drops reference to input namei data on failure.
830 static int __link_path_walk(const char *name
, struct nameidata
*nd
)
835 unsigned int lookup_flags
= nd
->flags
;
842 inode
= nd
->path
.dentry
->d_inode
;
844 lookup_flags
= LOOKUP_FOLLOW
| (nd
->flags
& LOOKUP_CONTINUE
);
846 /* At this point we know we have a real path component. */
852 nd
->flags
|= LOOKUP_CONTINUE
;
853 err
= exec_permission_lite(inode
);
858 c
= *(const unsigned char *)name
;
860 hash
= init_name_hash();
863 hash
= partial_name_hash(c
, hash
);
864 c
= *(const unsigned char *)name
;
865 } while (c
&& (c
!= '/'));
866 this.len
= name
- (const char *) this.name
;
867 this.hash
= end_name_hash(hash
);
869 /* remove trailing slashes? */
872 while (*++name
== '/');
874 goto last_with_slashes
;
877 * "." and ".." are special - ".." especially so because it has
878 * to be able to know about the current root directory and
879 * parent relationships.
881 if (this.name
[0] == '.') switch (this.len
) {
885 if (this.name
[1] != '.')
888 inode
= nd
->path
.dentry
->d_inode
;
894 * See if the low-level filesystem might want
895 * to use its own hash..
897 if (nd
->path
.dentry
->d_op
&& nd
->path
.dentry
->d_op
->d_hash
) {
898 err
= nd
->path
.dentry
->d_op
->d_hash(nd
->path
.dentry
,
903 /* This does the actual lookups.. */
904 err
= do_lookup(nd
, &this, &next
);
909 inode
= next
.dentry
->d_inode
;
913 if (inode
->i_op
->follow_link
) {
914 err
= do_follow_link(&next
, nd
);
918 inode
= nd
->path
.dentry
->d_inode
;
922 path_to_nameidata(&next
, nd
);
924 if (!inode
->i_op
->lookup
)
927 /* here ends the main loop */
930 lookup_flags
|= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
932 /* Clear LOOKUP_CONTINUE iff it was previously unset */
933 nd
->flags
&= lookup_flags
| ~LOOKUP_CONTINUE
;
934 if (lookup_flags
& LOOKUP_PARENT
)
936 if (this.name
[0] == '.') switch (this.len
) {
940 if (this.name
[1] != '.')
943 inode
= nd
->path
.dentry
->d_inode
;
948 if (nd
->path
.dentry
->d_op
&& nd
->path
.dentry
->d_op
->d_hash
) {
949 err
= nd
->path
.dentry
->d_op
->d_hash(nd
->path
.dentry
,
954 err
= do_lookup(nd
, &this, &next
);
957 inode
= next
.dentry
->d_inode
;
958 if ((lookup_flags
& LOOKUP_FOLLOW
)
959 && inode
&& inode
->i_op
->follow_link
) {
960 err
= do_follow_link(&next
, nd
);
963 inode
= nd
->path
.dentry
->d_inode
;
965 path_to_nameidata(&next
, nd
);
969 if (lookup_flags
& LOOKUP_DIRECTORY
) {
971 if (!inode
->i_op
->lookup
)
977 nd
->last_type
= LAST_NORM
;
978 if (this.name
[0] != '.')
981 nd
->last_type
= LAST_DOT
;
982 else if (this.len
== 2 && this.name
[1] == '.')
983 nd
->last_type
= LAST_DOTDOT
;
988 * We bypassed the ordinary revalidation routines.
989 * We may need to check the cached dentry for staleness.
991 if (nd
->path
.dentry
&& nd
->path
.dentry
->d_sb
&&
992 (nd
->path
.dentry
->d_sb
->s_type
->fs_flags
& FS_REVAL_DOT
)) {
994 /* Note: we do not d_invalidate() */
995 if (!nd
->path
.dentry
->d_op
->d_revalidate(
996 nd
->path
.dentry
, nd
))
1002 path_put_conditional(&next
, nd
);
1005 path_put(&nd
->path
);
1010 static int path_walk(const char *name
, struct nameidata
*nd
)
1012 current
->total_link_count
= 0;
1013 return link_path_walk(name
, nd
);
1016 static int path_init(int dfd
, const char *name
, unsigned int flags
, struct nameidata
*nd
)
1022 nd
->last_type
= LAST_ROOT
; /* if there are only slashes... */
1025 nd
->root
.mnt
= NULL
;
1029 nd
->path
= nd
->root
;
1030 path_get(&nd
->root
);
1031 } else if (dfd
== AT_FDCWD
) {
1032 struct fs_struct
*fs
= current
->fs
;
1033 read_lock(&fs
->lock
);
1036 read_unlock(&fs
->lock
);
1038 struct dentry
*dentry
;
1040 file
= fget_light(dfd
, &fput_needed
);
1045 dentry
= file
->f_path
.dentry
;
1048 if (!S_ISDIR(dentry
->d_inode
->i_mode
))
1051 retval
= file_permission(file
, MAY_EXEC
);
1055 nd
->path
= file
->f_path
;
1056 path_get(&file
->f_path
);
1058 fput_light(file
, fput_needed
);
1063 fput_light(file
, fput_needed
);
1068 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
1069 static int do_path_lookup(int dfd
, const char *name
,
1070 unsigned int flags
, struct nameidata
*nd
)
1072 int retval
= path_init(dfd
, name
, flags
, nd
);
1074 retval
= path_walk(name
, nd
);
1075 if (unlikely(!retval
&& !audit_dummy_context() && nd
->path
.dentry
&&
1076 nd
->path
.dentry
->d_inode
))
1077 audit_inode(name
, nd
->path
.dentry
);
1079 path_put(&nd
->root
);
1080 nd
->root
.mnt
= NULL
;
1085 int path_lookup(const char *name
, unsigned int flags
,
1086 struct nameidata
*nd
)
1088 return do_path_lookup(AT_FDCWD
, name
, flags
, nd
);
1091 int kern_path(const char *name
, unsigned int flags
, struct path
*path
)
1093 struct nameidata nd
;
1094 int res
= do_path_lookup(AT_FDCWD
, name
, flags
, &nd
);
1101 * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
1102 * @dentry: pointer to dentry of the base directory
1103 * @mnt: pointer to vfs mount of the base directory
1104 * @name: pointer to file name
1105 * @flags: lookup flags
1106 * @nd: pointer to nameidata
1108 int vfs_path_lookup(struct dentry
*dentry
, struct vfsmount
*mnt
,
1109 const char *name
, unsigned int flags
,
1110 struct nameidata
*nd
)
1114 /* same as do_path_lookup */
1115 nd
->last_type
= LAST_ROOT
;
1119 nd
->path
.dentry
= dentry
;
1121 path_get(&nd
->path
);
1122 nd
->root
= nd
->path
;
1123 path_get(&nd
->root
);
1125 retval
= path_walk(name
, nd
);
1126 if (unlikely(!retval
&& !audit_dummy_context() && nd
->path
.dentry
&&
1127 nd
->path
.dentry
->d_inode
))
1128 audit_inode(name
, nd
->path
.dentry
);
1130 path_put(&nd
->root
);
1131 nd
->root
.mnt
= NULL
;
1137 * path_lookup_open - lookup a file path with open intent
1138 * @dfd: the directory to use as base, or AT_FDCWD
1139 * @name: pointer to file name
1140 * @lookup_flags: lookup intent flags
1141 * @nd: pointer to nameidata
1142 * @open_flags: open intent flags
1144 static int path_lookup_open(int dfd
, const char *name
,
1145 unsigned int lookup_flags
, struct nameidata
*nd
, int open_flags
)
1147 struct file
*filp
= get_empty_filp();
1152 nd
->intent
.open
.file
= filp
;
1153 nd
->intent
.open
.flags
= open_flags
;
1154 nd
->intent
.open
.create_mode
= 0;
1155 err
= do_path_lookup(dfd
, name
, lookup_flags
|LOOKUP_OPEN
, nd
);
1156 if (IS_ERR(nd
->intent
.open
.file
)) {
1158 err
= PTR_ERR(nd
->intent
.open
.file
);
1159 path_put(&nd
->path
);
1161 } else if (err
!= 0)
1162 release_open_intent(nd
);
1166 static struct dentry
*__lookup_hash(struct qstr
*name
,
1167 struct dentry
*base
, struct nameidata
*nd
)
1169 struct dentry
*dentry
;
1170 struct inode
*inode
;
1173 inode
= base
->d_inode
;
1176 * See if the low-level filesystem might want
1177 * to use its own hash..
1179 if (base
->d_op
&& base
->d_op
->d_hash
) {
1180 err
= base
->d_op
->d_hash(base
, name
);
1181 dentry
= ERR_PTR(err
);
1186 dentry
= cached_lookup(base
, name
, nd
);
1190 /* Don't create child dentry for a dead directory. */
1191 dentry
= ERR_PTR(-ENOENT
);
1192 if (IS_DEADDIR(inode
))
1195 new = d_alloc(base
, name
);
1196 dentry
= ERR_PTR(-ENOMEM
);
1199 dentry
= inode
->i_op
->lookup(inode
, new, nd
);
1210 * Restricted form of lookup. Doesn't follow links, single-component only,
1211 * needs parent already locked. Doesn't follow mounts.
1214 static struct dentry
*lookup_hash(struct nameidata
*nd
)
1218 err
= inode_permission(nd
->path
.dentry
->d_inode
, MAY_EXEC
);
1220 return ERR_PTR(err
);
1221 return __lookup_hash(&nd
->last
, nd
->path
.dentry
, nd
);
1224 static int __lookup_one_len(const char *name
, struct qstr
*this,
1225 struct dentry
*base
, int len
)
1235 hash
= init_name_hash();
1237 c
= *(const unsigned char *)name
++;
1238 if (c
== '/' || c
== '\0')
1240 hash
= partial_name_hash(c
, hash
);
1242 this->hash
= end_name_hash(hash
);
1247 * lookup_one_len - filesystem helper to lookup single pathname component
1248 * @name: pathname component to lookup
1249 * @base: base directory to lookup from
1250 * @len: maximum length @len should be interpreted to
1252 * Note that this routine is purely a helper for filesystem usage and should
1253 * not be called by generic code. Also note that by using this function the
1254 * nameidata argument is passed to the filesystem methods and a filesystem
1255 * using this helper needs to be prepared for that.
1257 struct dentry
*lookup_one_len(const char *name
, struct dentry
*base
, int len
)
1262 WARN_ON_ONCE(!mutex_is_locked(&base
->d_inode
->i_mutex
));
1264 err
= __lookup_one_len(name
, &this, base
, len
);
1266 return ERR_PTR(err
);
1268 err
= inode_permission(base
->d_inode
, MAY_EXEC
);
1270 return ERR_PTR(err
);
1271 return __lookup_hash(&this, base
, NULL
);
1275 * lookup_one_noperm - bad hack for sysfs
1276 * @name: pathname component to lookup
1277 * @base: base directory to lookup from
1279 * This is a variant of lookup_one_len that doesn't perform any permission
1280 * checks. It's a horrible hack to work around the braindead sysfs
1281 * architecture and should not be used anywhere else.
1283 * DON'T USE THIS FUNCTION EVER, thanks.
1285 struct dentry
*lookup_one_noperm(const char *name
, struct dentry
*base
)
1290 err
= __lookup_one_len(name
, &this, base
, strlen(name
));
1292 return ERR_PTR(err
);
1293 return __lookup_hash(&this, base
, NULL
);
1296 int user_path_at(int dfd
, const char __user
*name
, unsigned flags
,
1299 struct nameidata nd
;
1300 char *tmp
= getname(name
);
1301 int err
= PTR_ERR(tmp
);
1304 BUG_ON(flags
& LOOKUP_PARENT
);
1306 err
= do_path_lookup(dfd
, tmp
, flags
, &nd
);
1314 static int user_path_parent(int dfd
, const char __user
*path
,
1315 struct nameidata
*nd
, char **name
)
1317 char *s
= getname(path
);
1323 error
= do_path_lookup(dfd
, s
, LOOKUP_PARENT
, nd
);
1333 * It's inline, so penalty for filesystems that don't use sticky bit is
1336 static inline int check_sticky(struct inode
*dir
, struct inode
*inode
)
1338 uid_t fsuid
= current_fsuid();
1340 if (!(dir
->i_mode
& S_ISVTX
))
1342 if (inode
->i_uid
== fsuid
)
1344 if (dir
->i_uid
== fsuid
)
1346 return !capable(CAP_FOWNER
);
1350 * Check whether we can remove a link victim from directory dir, check
1351 * whether the type of victim is right.
1352 * 1. We can't do it if dir is read-only (done in permission())
1353 * 2. We should have write and exec permissions on dir
1354 * 3. We can't remove anything from append-only dir
1355 * 4. We can't do anything with immutable dir (done in permission())
1356 * 5. If the sticky bit on dir is set we should either
1357 * a. be owner of dir, or
1358 * b. be owner of victim, or
1359 * c. have CAP_FOWNER capability
1360 * 6. If the victim is append-only or immutable we can't do antyhing with
1361 * links pointing to it.
1362 * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
1363 * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
1364 * 9. We can't remove a root or mountpoint.
1365 * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
1366 * nfs_async_unlink().
1368 static int may_delete(struct inode
*dir
,struct dentry
*victim
,int isdir
)
1372 if (!victim
->d_inode
)
1375 BUG_ON(victim
->d_parent
->d_inode
!= dir
);
1376 audit_inode_child(victim
->d_name
.name
, victim
, dir
);
1378 error
= inode_permission(dir
, MAY_WRITE
| MAY_EXEC
);
1383 if (check_sticky(dir
, victim
->d_inode
)||IS_APPEND(victim
->d_inode
)||
1384 IS_IMMUTABLE(victim
->d_inode
) || IS_SWAPFILE(victim
->d_inode
))
1387 if (!S_ISDIR(victim
->d_inode
->i_mode
))
1389 if (IS_ROOT(victim
))
1391 } else if (S_ISDIR(victim
->d_inode
->i_mode
))
1393 if (IS_DEADDIR(dir
))
1395 if (victim
->d_flags
& DCACHE_NFSFS_RENAMED
)
1400 /* Check whether we can create an object with dentry child in directory
1402 * 1. We can't do it if child already exists (open has special treatment for
1403 * this case, but since we are inlined it's OK)
1404 * 2. We can't do it if dir is read-only (done in permission())
1405 * 3. We should have write and exec permissions on dir
1406 * 4. We can't do it if dir is immutable (done in permission())
1408 static inline int may_create(struct inode
*dir
, struct dentry
*child
)
1412 if (IS_DEADDIR(dir
))
1414 return inode_permission(dir
, MAY_WRITE
| MAY_EXEC
);
1418 * O_DIRECTORY translates into forcing a directory lookup.
1420 static inline int lookup_flags(unsigned int f
)
1422 unsigned long retval
= LOOKUP_FOLLOW
;
1425 retval
&= ~LOOKUP_FOLLOW
;
1427 if (f
& O_DIRECTORY
)
1428 retval
|= LOOKUP_DIRECTORY
;
1434 * p1 and p2 should be directories on the same fs.
1436 struct dentry
*lock_rename(struct dentry
*p1
, struct dentry
*p2
)
1441 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1445 mutex_lock(&p1
->d_inode
->i_sb
->s_vfs_rename_mutex
);
1447 p
= d_ancestor(p2
, p1
);
1449 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1450 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1454 p
= d_ancestor(p1
, p2
);
1456 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1457 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1461 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1462 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1466 void unlock_rename(struct dentry
*p1
, struct dentry
*p2
)
1468 mutex_unlock(&p1
->d_inode
->i_mutex
);
1470 mutex_unlock(&p2
->d_inode
->i_mutex
);
1471 mutex_unlock(&p1
->d_inode
->i_sb
->s_vfs_rename_mutex
);
1475 int vfs_create(struct inode
*dir
, struct dentry
*dentry
, int mode
,
1476 struct nameidata
*nd
)
1478 int error
= may_create(dir
, dentry
);
1483 if (!dir
->i_op
->create
)
1484 return -EACCES
; /* shouldn't it be ENOSYS? */
1487 error
= security_inode_create(dir
, dentry
, mode
);
1491 error
= dir
->i_op
->create(dir
, dentry
, mode
, nd
);
1493 fsnotify_create(dir
, dentry
);
1497 int may_open(struct path
*path
, int acc_mode
, int flag
)
1499 struct dentry
*dentry
= path
->dentry
;
1500 struct inode
*inode
= dentry
->d_inode
;
1506 switch (inode
->i_mode
& S_IFMT
) {
1510 if (acc_mode
& MAY_WRITE
)
1515 if (path
->mnt
->mnt_flags
& MNT_NODEV
)
1524 error
= inode_permission(inode
, acc_mode
);
1528 error
= ima_path_check(path
,
1529 acc_mode
& (MAY_READ
| MAY_WRITE
| MAY_EXEC
),
1534 * An append-only file must be opened in append mode for writing.
1536 if (IS_APPEND(inode
)) {
1538 if ((flag
& FMODE_WRITE
) && !(flag
& O_APPEND
))
1544 /* O_NOATIME can only be set by the owner or superuser */
1545 if (flag
& O_NOATIME
)
1546 if (!is_owner_or_cap(inode
)) {
1552 * Ensure there are no outstanding leases on the file.
1554 error
= break_lease(inode
, flag
);
1558 if (flag
& O_TRUNC
) {
1559 error
= get_write_access(inode
);
1564 * Refuse to truncate files with mandatory locks held on them.
1566 error
= locks_verify_locked(inode
);
1568 error
= security_path_truncate(path
, 0,
1569 ATTR_MTIME
|ATTR_CTIME
|ATTR_OPEN
);
1573 error
= do_truncate(dentry
, 0,
1574 ATTR_MTIME
|ATTR_CTIME
|ATTR_OPEN
,
1577 put_write_access(inode
);
1581 if (flag
& FMODE_WRITE
)
1586 ima_counts_put(path
, acc_mode
?
1587 acc_mode
& (MAY_READ
| MAY_WRITE
| MAY_EXEC
) :
1588 ACC_MODE(flag
) & (MAY_READ
| MAY_WRITE
));
1593 * Be careful about ever adding any more callers of this
1594 * function. Its flags must be in the namei format, not
1595 * what get passed to sys_open().
1597 static int __open_namei_create(struct nameidata
*nd
, struct path
*path
,
1601 struct dentry
*dir
= nd
->path
.dentry
;
1603 if (!IS_POSIXACL(dir
->d_inode
))
1604 mode
&= ~current_umask();
1605 error
= security_path_mknod(&nd
->path
, path
->dentry
, mode
, 0);
1608 error
= vfs_create(dir
->d_inode
, path
->dentry
, mode
, nd
);
1610 mutex_unlock(&dir
->d_inode
->i_mutex
);
1611 dput(nd
->path
.dentry
);
1612 nd
->path
.dentry
= path
->dentry
;
1615 /* Don't check for write permission, don't truncate */
1616 return may_open(&nd
->path
, 0, flag
& ~O_TRUNC
);
1620 * Note that while the flag value (low two bits) for sys_open means:
1625 * it is changed into
1626 * 00 - no permissions needed
1627 * 01 - read-permission
1628 * 10 - write-permission
1630 * for the internal routines (ie open_namei()/follow_link() etc)
1631 * This is more logical, and also allows the 00 "no perm needed"
1632 * to be used for symlinks (where the permissions are checked
1636 static inline int open_to_namei_flags(int flag
)
1638 if ((flag
+1) & O_ACCMODE
)
1643 static int open_will_write_to_fs(int flag
, struct inode
*inode
)
1646 * We'll never write to the fs underlying
1649 if (special_file(inode
->i_mode
))
1651 return (flag
& O_TRUNC
);
1655 * Note that the low bits of the passed in "open_flag"
1656 * are not the same as in the local variable "flag". See
1657 * open_to_namei_flags() for more details.
1659 struct file
*do_filp_open(int dfd
, const char *pathname
,
1660 int open_flag
, int mode
, int acc_mode
)
1663 struct nameidata nd
;
1669 int flag
= open_to_namei_flags(open_flag
);
1672 acc_mode
= MAY_OPEN
| ACC_MODE(flag
);
1674 /* O_TRUNC implies we need access checks for write permissions */
1676 acc_mode
|= MAY_WRITE
;
1678 /* Allow the LSM permission hook to distinguish append
1679 access from general write access. */
1680 if (flag
& O_APPEND
)
1681 acc_mode
|= MAY_APPEND
;
1684 * The simplest case - just a plain lookup.
1686 if (!(flag
& O_CREAT
)) {
1687 error
= path_lookup_open(dfd
, pathname
, lookup_flags(flag
),
1690 return ERR_PTR(error
);
1695 * Create - we need to know the parent.
1697 error
= path_init(dfd
, pathname
, LOOKUP_PARENT
, &nd
);
1699 return ERR_PTR(error
);
1700 error
= path_walk(pathname
, &nd
);
1704 return ERR_PTR(error
);
1706 if (unlikely(!audit_dummy_context()))
1707 audit_inode(pathname
, nd
.path
.dentry
);
1710 * We have the parent and last component. First of all, check
1711 * that we are not asked to creat(2) an obvious directory - that
1715 if (nd
.last_type
!= LAST_NORM
|| nd
.last
.name
[nd
.last
.len
])
1719 filp
= get_empty_filp();
1722 nd
.intent
.open
.file
= filp
;
1723 nd
.intent
.open
.flags
= flag
;
1724 nd
.intent
.open
.create_mode
= mode
;
1725 dir
= nd
.path
.dentry
;
1726 nd
.flags
&= ~LOOKUP_PARENT
;
1727 nd
.flags
|= LOOKUP_CREATE
| LOOKUP_OPEN
;
1729 nd
.flags
|= LOOKUP_EXCL
;
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
);
1765 ima_counts_put(&nd
.path
,
1766 acc_mode
& (MAY_READ
| MAY_WRITE
|
1768 mnt_drop_write(nd
.path
.mnt
);
1775 * It already exists.
1777 mutex_unlock(&dir
->d_inode
->i_mutex
);
1778 audit_inode(pathname
, path
.dentry
);
1784 if (__follow_mount(&path
)) {
1786 if (flag
& O_NOFOLLOW
)
1791 if (!path
.dentry
->d_inode
)
1793 if (path
.dentry
->d_inode
->i_op
->follow_link
)
1796 path_to_nameidata(&path
, &nd
);
1798 if (path
.dentry
->d_inode
&& S_ISDIR(path
.dentry
->d_inode
->i_mode
))
1803 * 1. may_open() truncates a file
1804 * 2. a rw->ro mount transition occurs
1805 * 3. nameidata_to_filp() fails due to
1807 * That would be inconsistent, and should
1808 * be avoided. Taking this mnt write here
1809 * ensures that (2) can not occur.
1811 will_write
= open_will_write_to_fs(flag
, nd
.path
.dentry
->d_inode
);
1813 error
= mnt_want_write(nd
.path
.mnt
);
1817 error
= may_open(&nd
.path
, acc_mode
, flag
);
1820 mnt_drop_write(nd
.path
.mnt
);
1823 filp
= nameidata_to_filp(&nd
, open_flag
);
1825 ima_counts_put(&nd
.path
,
1826 acc_mode
& (MAY_READ
| MAY_WRITE
| MAY_EXEC
));
1828 * It is now safe to drop the mnt write
1829 * because the filp has had a write taken
1833 mnt_drop_write(nd
.path
.mnt
);
1839 mutex_unlock(&dir
->d_inode
->i_mutex
);
1841 path_put_conditional(&path
, &nd
);
1843 if (!IS_ERR(nd
.intent
.open
.file
))
1844 release_open_intent(&nd
);
1849 return ERR_PTR(error
);
1853 if (flag
& O_NOFOLLOW
)
1856 * This is subtle. Instead of calling do_follow_link() we do the
1857 * thing by hands. The reason is that this way we have zero link_count
1858 * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT.
1859 * After that we have the parent and last component, i.e.
1860 * we are in the same situation as after the first path_walk().
1861 * Well, almost - if the last component is normal we get its copy
1862 * stored in nd->last.name and we will have to putname() it when we
1863 * are done. Procfs-like symlinks just set LAST_BIND.
1865 nd
.flags
|= LOOKUP_PARENT
;
1866 error
= security_inode_follow_link(path
.dentry
, &nd
);
1869 error
= __do_follow_link(&path
, &nd
);
1871 /* Does someone understand code flow here? Or it is only
1872 * me so stupid? Anathema to whoever designed this non-sense
1873 * with "intent.open".
1875 release_open_intent(&nd
);
1878 return ERR_PTR(error
);
1880 nd
.flags
&= ~LOOKUP_PARENT
;
1881 if (nd
.last_type
== LAST_BIND
)
1884 if (nd
.last_type
!= LAST_NORM
)
1886 if (nd
.last
.name
[nd
.last
.len
]) {
1887 __putname(nd
.last
.name
);
1892 __putname(nd
.last
.name
);
1895 dir
= nd
.path
.dentry
;
1896 mutex_lock(&dir
->d_inode
->i_mutex
);
1897 path
.dentry
= lookup_hash(&nd
);
1898 path
.mnt
= nd
.path
.mnt
;
1899 __putname(nd
.last
.name
);
1904 * filp_open - open file and return file pointer
1906 * @filename: path to open
1907 * @flags: open flags as per the open(2) second argument
1908 * @mode: mode for the new file if O_CREAT is set, else ignored
1910 * This is the helper to open a file from kernelspace if you really
1911 * have to. But in generally you should not do this, so please move
1912 * along, nothing to see here..
1914 struct file
*filp_open(const char *filename
, int flags
, int mode
)
1916 return do_filp_open(AT_FDCWD
, filename
, flags
, mode
, 0);
1918 EXPORT_SYMBOL(filp_open
);
1921 * lookup_create - lookup a dentry, creating it if it doesn't exist
1922 * @nd: nameidata info
1923 * @is_dir: directory flag
1925 * Simple function to lookup and return a dentry and create it
1926 * if it doesn't exist. Is SMP-safe.
1928 * Returns with nd->path.dentry->d_inode->i_mutex locked.
1930 struct dentry
*lookup_create(struct nameidata
*nd
, int is_dir
)
1932 struct dentry
*dentry
= ERR_PTR(-EEXIST
);
1934 mutex_lock_nested(&nd
->path
.dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1936 * Yucky last component or no last component at all?
1937 * (foo/., foo/.., /////)
1939 if (nd
->last_type
!= LAST_NORM
)
1941 nd
->flags
&= ~LOOKUP_PARENT
;
1942 nd
->flags
|= LOOKUP_CREATE
| LOOKUP_EXCL
;
1943 nd
->intent
.open
.flags
= O_EXCL
;
1946 * Do the final lookup.
1948 dentry
= lookup_hash(nd
);
1952 if (dentry
->d_inode
)
1955 * Special case - lookup gave negative, but... we had foo/bar/
1956 * From the vfs_mknod() POV we just have a negative dentry -
1957 * all is fine. Let's be bastards - you had / on the end, you've
1958 * been asking for (non-existent) directory. -ENOENT for you.
1960 if (unlikely(!is_dir
&& nd
->last
.name
[nd
->last
.len
])) {
1962 dentry
= ERR_PTR(-ENOENT
);
1967 dentry
= ERR_PTR(-EEXIST
);
1971 EXPORT_SYMBOL_GPL(lookup_create
);
1973 int vfs_mknod(struct inode
*dir
, struct dentry
*dentry
, int mode
, dev_t dev
)
1975 int error
= may_create(dir
, dentry
);
1980 if ((S_ISCHR(mode
) || S_ISBLK(mode
)) && !capable(CAP_MKNOD
))
1983 if (!dir
->i_op
->mknod
)
1986 error
= devcgroup_inode_mknod(mode
, dev
);
1990 error
= security_inode_mknod(dir
, dentry
, mode
, dev
);
1995 error
= dir
->i_op
->mknod(dir
, dentry
, mode
, dev
);
1997 fsnotify_create(dir
, dentry
);
2001 static int may_mknod(mode_t mode
)
2003 switch (mode
& S_IFMT
) {
2009 case 0: /* zero mode translates to S_IFREG */
2018 SYSCALL_DEFINE4(mknodat
, int, dfd
, const char __user
*, filename
, int, mode
,
2023 struct dentry
*dentry
;
2024 struct nameidata nd
;
2029 error
= user_path_parent(dfd
, filename
, &nd
, &tmp
);
2033 dentry
= lookup_create(&nd
, 0);
2034 if (IS_ERR(dentry
)) {
2035 error
= PTR_ERR(dentry
);
2038 if (!IS_POSIXACL(nd
.path
.dentry
->d_inode
))
2039 mode
&= ~current_umask();
2040 error
= may_mknod(mode
);
2043 error
= mnt_want_write(nd
.path
.mnt
);
2046 error
= security_path_mknod(&nd
.path
, dentry
, mode
, dev
);
2048 goto out_drop_write
;
2049 switch (mode
& S_IFMT
) {
2050 case 0: case S_IFREG
:
2051 error
= vfs_create(nd
.path
.dentry
->d_inode
,dentry
,mode
,&nd
);
2053 case S_IFCHR
: case S_IFBLK
:
2054 error
= vfs_mknod(nd
.path
.dentry
->d_inode
,dentry
,mode
,
2055 new_decode_dev(dev
));
2057 case S_IFIFO
: case S_IFSOCK
:
2058 error
= vfs_mknod(nd
.path
.dentry
->d_inode
,dentry
,mode
,0);
2062 mnt_drop_write(nd
.path
.mnt
);
2066 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2073 SYSCALL_DEFINE3(mknod
, const char __user
*, filename
, int, mode
, unsigned, dev
)
2075 return sys_mknodat(AT_FDCWD
, filename
, mode
, dev
);
2078 int vfs_mkdir(struct inode
*dir
, struct dentry
*dentry
, int mode
)
2080 int error
= may_create(dir
, dentry
);
2085 if (!dir
->i_op
->mkdir
)
2088 mode
&= (S_IRWXUGO
|S_ISVTX
);
2089 error
= security_inode_mkdir(dir
, dentry
, mode
);
2094 error
= dir
->i_op
->mkdir(dir
, dentry
, mode
);
2096 fsnotify_mkdir(dir
, dentry
);
2100 SYSCALL_DEFINE3(mkdirat
, int, dfd
, const char __user
*, pathname
, int, mode
)
2104 struct dentry
*dentry
;
2105 struct nameidata nd
;
2107 error
= user_path_parent(dfd
, pathname
, &nd
, &tmp
);
2111 dentry
= lookup_create(&nd
, 1);
2112 error
= PTR_ERR(dentry
);
2116 if (!IS_POSIXACL(nd
.path
.dentry
->d_inode
))
2117 mode
&= ~current_umask();
2118 error
= mnt_want_write(nd
.path
.mnt
);
2121 error
= security_path_mkdir(&nd
.path
, dentry
, mode
);
2123 goto out_drop_write
;
2124 error
= vfs_mkdir(nd
.path
.dentry
->d_inode
, dentry
, mode
);
2126 mnt_drop_write(nd
.path
.mnt
);
2130 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2137 SYSCALL_DEFINE2(mkdir
, const char __user
*, pathname
, int, mode
)
2139 return sys_mkdirat(AT_FDCWD
, pathname
, mode
);
2143 * We try to drop the dentry early: we should have
2144 * a usage count of 2 if we're the only user of this
2145 * dentry, and if that is true (possibly after pruning
2146 * the dcache), then we drop the dentry now.
2148 * A low-level filesystem can, if it choses, legally
2151 * if (!d_unhashed(dentry))
2154 * if it cannot handle the case of removing a directory
2155 * that is still in use by something else..
2157 void dentry_unhash(struct dentry
*dentry
)
2160 shrink_dcache_parent(dentry
);
2161 spin_lock(&dcache_lock
);
2162 spin_lock(&dentry
->d_lock
);
2163 if (atomic_read(&dentry
->d_count
) == 2)
2165 spin_unlock(&dentry
->d_lock
);
2166 spin_unlock(&dcache_lock
);
2169 int vfs_rmdir(struct inode
*dir
, struct dentry
*dentry
)
2171 int error
= may_delete(dir
, dentry
, 1);
2176 if (!dir
->i_op
->rmdir
)
2181 mutex_lock(&dentry
->d_inode
->i_mutex
);
2182 dentry_unhash(dentry
);
2183 if (d_mountpoint(dentry
))
2186 error
= security_inode_rmdir(dir
, dentry
);
2188 error
= dir
->i_op
->rmdir(dir
, dentry
);
2190 dentry
->d_inode
->i_flags
|= S_DEAD
;
2193 mutex_unlock(&dentry
->d_inode
->i_mutex
);
2202 static long do_rmdir(int dfd
, const char __user
*pathname
)
2206 struct dentry
*dentry
;
2207 struct nameidata nd
;
2209 error
= user_path_parent(dfd
, pathname
, &nd
, &name
);
2213 switch(nd
.last_type
) {
2225 nd
.flags
&= ~LOOKUP_PARENT
;
2227 mutex_lock_nested(&nd
.path
.dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
2228 dentry
= lookup_hash(&nd
);
2229 error
= PTR_ERR(dentry
);
2232 error
= mnt_want_write(nd
.path
.mnt
);
2235 error
= security_path_rmdir(&nd
.path
, dentry
);
2238 error
= vfs_rmdir(nd
.path
.dentry
->d_inode
, dentry
);
2240 mnt_drop_write(nd
.path
.mnt
);
2244 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2251 SYSCALL_DEFINE1(rmdir
, const char __user
*, pathname
)
2253 return do_rmdir(AT_FDCWD
, pathname
);
2256 int vfs_unlink(struct inode
*dir
, struct dentry
*dentry
)
2258 int error
= may_delete(dir
, dentry
, 0);
2263 if (!dir
->i_op
->unlink
)
2268 mutex_lock(&dentry
->d_inode
->i_mutex
);
2269 if (d_mountpoint(dentry
))
2272 error
= security_inode_unlink(dir
, dentry
);
2274 error
= dir
->i_op
->unlink(dir
, dentry
);
2276 mutex_unlock(&dentry
->d_inode
->i_mutex
);
2278 /* We don't d_delete() NFS sillyrenamed files--they still exist. */
2279 if (!error
&& !(dentry
->d_flags
& DCACHE_NFSFS_RENAMED
)) {
2280 fsnotify_link_count(dentry
->d_inode
);
2288 * Make sure that the actual truncation of the file will occur outside its
2289 * directory's i_mutex. Truncate can take a long time if there is a lot of
2290 * writeout happening, and we don't want to prevent access to the directory
2291 * while waiting on the I/O.
2293 static long do_unlinkat(int dfd
, const char __user
*pathname
)
2297 struct dentry
*dentry
;
2298 struct nameidata nd
;
2299 struct inode
*inode
= NULL
;
2301 error
= user_path_parent(dfd
, pathname
, &nd
, &name
);
2306 if (nd
.last_type
!= LAST_NORM
)
2309 nd
.flags
&= ~LOOKUP_PARENT
;
2311 mutex_lock_nested(&nd
.path
.dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
2312 dentry
= lookup_hash(&nd
);
2313 error
= PTR_ERR(dentry
);
2314 if (!IS_ERR(dentry
)) {
2315 /* Why not before? Because we want correct error value */
2316 if (nd
.last
.name
[nd
.last
.len
])
2318 inode
= dentry
->d_inode
;
2320 atomic_inc(&inode
->i_count
);
2321 error
= mnt_want_write(nd
.path
.mnt
);
2324 error
= security_path_unlink(&nd
.path
, dentry
);
2327 error
= vfs_unlink(nd
.path
.dentry
->d_inode
, dentry
);
2329 mnt_drop_write(nd
.path
.mnt
);
2333 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2335 iput(inode
); /* truncate the inode here */
2342 error
= !dentry
->d_inode
? -ENOENT
:
2343 S_ISDIR(dentry
->d_inode
->i_mode
) ? -EISDIR
: -ENOTDIR
;
2347 SYSCALL_DEFINE3(unlinkat
, int, dfd
, const char __user
*, pathname
, int, flag
)
2349 if ((flag
& ~AT_REMOVEDIR
) != 0)
2352 if (flag
& AT_REMOVEDIR
)
2353 return do_rmdir(dfd
, pathname
);
2355 return do_unlinkat(dfd
, pathname
);
2358 SYSCALL_DEFINE1(unlink
, const char __user
*, pathname
)
2360 return do_unlinkat(AT_FDCWD
, pathname
);
2363 int vfs_symlink(struct inode
*dir
, struct dentry
*dentry
, const char *oldname
)
2365 int error
= may_create(dir
, dentry
);
2370 if (!dir
->i_op
->symlink
)
2373 error
= security_inode_symlink(dir
, dentry
, oldname
);
2378 error
= dir
->i_op
->symlink(dir
, dentry
, oldname
);
2380 fsnotify_create(dir
, dentry
);
2384 SYSCALL_DEFINE3(symlinkat
, const char __user
*, oldname
,
2385 int, newdfd
, const char __user
*, newname
)
2390 struct dentry
*dentry
;
2391 struct nameidata nd
;
2393 from
= getname(oldname
);
2395 return PTR_ERR(from
);
2397 error
= user_path_parent(newdfd
, newname
, &nd
, &to
);
2401 dentry
= lookup_create(&nd
, 0);
2402 error
= PTR_ERR(dentry
);
2406 error
= mnt_want_write(nd
.path
.mnt
);
2409 error
= security_path_symlink(&nd
.path
, dentry
, from
);
2411 goto out_drop_write
;
2412 error
= vfs_symlink(nd
.path
.dentry
->d_inode
, dentry
, from
);
2414 mnt_drop_write(nd
.path
.mnt
);
2418 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2426 SYSCALL_DEFINE2(symlink
, const char __user
*, oldname
, const char __user
*, newname
)
2428 return sys_symlinkat(oldname
, AT_FDCWD
, newname
);
2431 int vfs_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*new_dentry
)
2433 struct inode
*inode
= old_dentry
->d_inode
;
2439 error
= may_create(dir
, new_dentry
);
2443 if (dir
->i_sb
!= inode
->i_sb
)
2447 * A link to an append-only or immutable file cannot be created.
2449 if (IS_APPEND(inode
) || IS_IMMUTABLE(inode
))
2451 if (!dir
->i_op
->link
)
2453 if (S_ISDIR(inode
->i_mode
))
2456 error
= security_inode_link(old_dentry
, dir
, new_dentry
);
2460 mutex_lock(&inode
->i_mutex
);
2462 error
= dir
->i_op
->link(old_dentry
, dir
, new_dentry
);
2463 mutex_unlock(&inode
->i_mutex
);
2465 fsnotify_link(dir
, inode
, new_dentry
);
2470 * Hardlinks are often used in delicate situations. We avoid
2471 * security-related surprises by not following symlinks on the
2474 * We don't follow them on the oldname either to be compatible
2475 * with linux 2.0, and to avoid hard-linking to directories
2476 * and other special files. --ADM
2478 SYSCALL_DEFINE5(linkat
, int, olddfd
, const char __user
*, oldname
,
2479 int, newdfd
, const char __user
*, newname
, int, flags
)
2481 struct dentry
*new_dentry
;
2482 struct nameidata nd
;
2483 struct path old_path
;
2487 if ((flags
& ~AT_SYMLINK_FOLLOW
) != 0)
2490 error
= user_path_at(olddfd
, oldname
,
2491 flags
& AT_SYMLINK_FOLLOW
? LOOKUP_FOLLOW
: 0,
2496 error
= user_path_parent(newdfd
, newname
, &nd
, &to
);
2500 if (old_path
.mnt
!= nd
.path
.mnt
)
2502 new_dentry
= lookup_create(&nd
, 0);
2503 error
= PTR_ERR(new_dentry
);
2504 if (IS_ERR(new_dentry
))
2506 error
= mnt_want_write(nd
.path
.mnt
);
2509 error
= security_path_link(old_path
.dentry
, &nd
.path
, new_dentry
);
2511 goto out_drop_write
;
2512 error
= vfs_link(old_path
.dentry
, nd
.path
.dentry
->d_inode
, new_dentry
);
2514 mnt_drop_write(nd
.path
.mnt
);
2518 mutex_unlock(&nd
.path
.dentry
->d_inode
->i_mutex
);
2523 path_put(&old_path
);
2528 SYSCALL_DEFINE2(link
, const char __user
*, oldname
, const char __user
*, newname
)
2530 return sys_linkat(AT_FDCWD
, oldname
, AT_FDCWD
, newname
, 0);
2534 * The worst of all namespace operations - renaming directory. "Perverted"
2535 * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
2537 * a) we can get into loop creation. Check is done in is_subdir().
2538 * b) race potential - two innocent renames can create a loop together.
2539 * That's where 4.4 screws up. Current fix: serialization on
2540 * sb->s_vfs_rename_mutex. We might be more accurate, but that's another
2542 * c) we have to lock _three_ objects - parents and victim (if it exists).
2543 * And that - after we got ->i_mutex on parents (until then we don't know
2544 * whether the target exists). Solution: try to be smart with locking
2545 * order for inodes. We rely on the fact that tree topology may change
2546 * only under ->s_vfs_rename_mutex _and_ that parent of the object we
2547 * move will be locked. Thus we can rank directories by the tree
2548 * (ancestors first) and rank all non-directories after them.
2549 * That works since everybody except rename does "lock parent, lookup,
2550 * lock child" and rename is under ->s_vfs_rename_mutex.
2551 * HOWEVER, it relies on the assumption that any object with ->lookup()
2552 * has no more than 1 dentry. If "hybrid" objects will ever appear,
2553 * we'd better make sure that there's no link(2) for them.
2554 * d) some filesystems don't support opened-but-unlinked directories,
2555 * either because of layout or because they are not ready to deal with
2556 * all cases correctly. The latter will be fixed (taking this sort of
2557 * stuff into VFS), but the former is not going away. Solution: the same
2558 * trick as in rmdir().
2559 * e) conversion from fhandle to dentry may come in the wrong moment - when
2560 * we are removing the target. Solution: we will have to grab ->i_mutex
2561 * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on
2562 * ->i_mutex on parents, which works but leads to some truely excessive
2565 static int vfs_rename_dir(struct inode
*old_dir
, struct dentry
*old_dentry
,
2566 struct inode
*new_dir
, struct dentry
*new_dentry
)
2569 struct inode
*target
;
2572 * If we are going to change the parent - check write permissions,
2573 * we'll need to flip '..'.
2575 if (new_dir
!= old_dir
) {
2576 error
= inode_permission(old_dentry
->d_inode
, MAY_WRITE
);
2581 error
= security_inode_rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2585 target
= new_dentry
->d_inode
;
2587 mutex_lock(&target
->i_mutex
);
2588 dentry_unhash(new_dentry
);
2590 if (d_mountpoint(old_dentry
)||d_mountpoint(new_dentry
))
2593 error
= old_dir
->i_op
->rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2596 target
->i_flags
|= S_DEAD
;
2597 mutex_unlock(&target
->i_mutex
);
2598 if (d_unhashed(new_dentry
))
2599 d_rehash(new_dentry
);
2603 if (!(old_dir
->i_sb
->s_type
->fs_flags
& FS_RENAME_DOES_D_MOVE
))
2604 d_move(old_dentry
,new_dentry
);
2608 static int vfs_rename_other(struct inode
*old_dir
, struct dentry
*old_dentry
,
2609 struct inode
*new_dir
, struct dentry
*new_dentry
)
2611 struct inode
*target
;
2614 error
= security_inode_rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2619 target
= new_dentry
->d_inode
;
2621 mutex_lock(&target
->i_mutex
);
2622 if (d_mountpoint(old_dentry
)||d_mountpoint(new_dentry
))
2625 error
= old_dir
->i_op
->rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2627 if (!(old_dir
->i_sb
->s_type
->fs_flags
& FS_RENAME_DOES_D_MOVE
))
2628 d_move(old_dentry
, new_dentry
);
2631 mutex_unlock(&target
->i_mutex
);
2636 int vfs_rename(struct inode
*old_dir
, struct dentry
*old_dentry
,
2637 struct inode
*new_dir
, struct dentry
*new_dentry
)
2640 int is_dir
= S_ISDIR(old_dentry
->d_inode
->i_mode
);
2641 const char *old_name
;
2643 if (old_dentry
->d_inode
== new_dentry
->d_inode
)
2646 error
= may_delete(old_dir
, old_dentry
, is_dir
);
2650 if (!new_dentry
->d_inode
)
2651 error
= may_create(new_dir
, new_dentry
);
2653 error
= may_delete(new_dir
, new_dentry
, is_dir
);
2657 if (!old_dir
->i_op
->rename
)
2660 vfs_dq_init(old_dir
);
2661 vfs_dq_init(new_dir
);
2663 old_name
= fsnotify_oldname_init(old_dentry
->d_name
.name
);
2666 error
= vfs_rename_dir(old_dir
,old_dentry
,new_dir
,new_dentry
);
2668 error
= vfs_rename_other(old_dir
,old_dentry
,new_dir
,new_dentry
);
2670 const char *new_name
= old_dentry
->d_name
.name
;
2671 fsnotify_move(old_dir
, new_dir
, old_name
, new_name
, is_dir
,
2672 new_dentry
->d_inode
, old_dentry
);
2674 fsnotify_oldname_free(old_name
);
2679 SYSCALL_DEFINE4(renameat
, int, olddfd
, const char __user
*, oldname
,
2680 int, newdfd
, const char __user
*, newname
)
2682 struct dentry
*old_dir
, *new_dir
;
2683 struct dentry
*old_dentry
, *new_dentry
;
2684 struct dentry
*trap
;
2685 struct nameidata oldnd
, newnd
;
2690 error
= user_path_parent(olddfd
, oldname
, &oldnd
, &from
);
2694 error
= user_path_parent(newdfd
, newname
, &newnd
, &to
);
2699 if (oldnd
.path
.mnt
!= newnd
.path
.mnt
)
2702 old_dir
= oldnd
.path
.dentry
;
2704 if (oldnd
.last_type
!= LAST_NORM
)
2707 new_dir
= newnd
.path
.dentry
;
2708 if (newnd
.last_type
!= LAST_NORM
)
2711 oldnd
.flags
&= ~LOOKUP_PARENT
;
2712 newnd
.flags
&= ~LOOKUP_PARENT
;
2713 newnd
.flags
|= LOOKUP_RENAME_TARGET
;
2715 trap
= lock_rename(new_dir
, old_dir
);
2717 old_dentry
= lookup_hash(&oldnd
);
2718 error
= PTR_ERR(old_dentry
);
2719 if (IS_ERR(old_dentry
))
2721 /* source must exist */
2723 if (!old_dentry
->d_inode
)
2725 /* unless the source is a directory trailing slashes give -ENOTDIR */
2726 if (!S_ISDIR(old_dentry
->d_inode
->i_mode
)) {
2728 if (oldnd
.last
.name
[oldnd
.last
.len
])
2730 if (newnd
.last
.name
[newnd
.last
.len
])
2733 /* source should not be ancestor of target */
2735 if (old_dentry
== trap
)
2737 new_dentry
= lookup_hash(&newnd
);
2738 error
= PTR_ERR(new_dentry
);
2739 if (IS_ERR(new_dentry
))
2741 /* target should not be an ancestor of source */
2743 if (new_dentry
== trap
)
2746 error
= mnt_want_write(oldnd
.path
.mnt
);
2749 error
= security_path_rename(&oldnd
.path
, old_dentry
,
2750 &newnd
.path
, new_dentry
);
2753 error
= vfs_rename(old_dir
->d_inode
, old_dentry
,
2754 new_dir
->d_inode
, new_dentry
);
2756 mnt_drop_write(oldnd
.path
.mnt
);
2762 unlock_rename(new_dir
, old_dir
);
2764 path_put(&newnd
.path
);
2767 path_put(&oldnd
.path
);
2773 SYSCALL_DEFINE2(rename
, const char __user
*, oldname
, const char __user
*, newname
)
2775 return sys_renameat(AT_FDCWD
, oldname
, AT_FDCWD
, newname
);
2778 int vfs_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
, const char *link
)
2782 len
= PTR_ERR(link
);
2787 if (len
> (unsigned) buflen
)
2789 if (copy_to_user(buffer
, link
, len
))
2796 * A helper for ->readlink(). This should be used *ONLY* for symlinks that
2797 * have ->follow_link() touching nd only in nd_set_link(). Using (or not
2798 * using) it for any given inode is up to filesystem.
2800 int generic_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
)
2802 struct nameidata nd
;
2807 cookie
= dentry
->d_inode
->i_op
->follow_link(dentry
, &nd
);
2809 return PTR_ERR(cookie
);
2811 res
= vfs_readlink(dentry
, buffer
, buflen
, nd_get_link(&nd
));
2812 if (dentry
->d_inode
->i_op
->put_link
)
2813 dentry
->d_inode
->i_op
->put_link(dentry
, &nd
, cookie
);
2817 int vfs_follow_link(struct nameidata
*nd
, const char *link
)
2819 return __vfs_follow_link(nd
, link
);
2822 /* get the link contents into pagecache */
2823 static char *page_getlink(struct dentry
* dentry
, struct page
**ppage
)
2827 struct address_space
*mapping
= dentry
->d_inode
->i_mapping
;
2828 page
= read_mapping_page(mapping
, 0, NULL
);
2833 nd_terminate_link(kaddr
, dentry
->d_inode
->i_size
, PAGE_SIZE
- 1);
2837 int page_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
)
2839 struct page
*page
= NULL
;
2840 char *s
= page_getlink(dentry
, &page
);
2841 int res
= vfs_readlink(dentry
,buffer
,buflen
,s
);
2844 page_cache_release(page
);
2849 void *page_follow_link_light(struct dentry
*dentry
, struct nameidata
*nd
)
2851 struct page
*page
= NULL
;
2852 nd_set_link(nd
, page_getlink(dentry
, &page
));
2856 void page_put_link(struct dentry
*dentry
, struct nameidata
*nd
, void *cookie
)
2858 struct page
*page
= cookie
;
2862 page_cache_release(page
);
2867 * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS
2869 int __page_symlink(struct inode
*inode
, const char *symname
, int len
, int nofs
)
2871 struct address_space
*mapping
= inode
->i_mapping
;
2876 unsigned int flags
= AOP_FLAG_UNINTERRUPTIBLE
;
2878 flags
|= AOP_FLAG_NOFS
;
2881 err
= pagecache_write_begin(NULL
, mapping
, 0, len
-1,
2882 flags
, &page
, &fsdata
);
2886 kaddr
= kmap_atomic(page
, KM_USER0
);
2887 memcpy(kaddr
, symname
, len
-1);
2888 kunmap_atomic(kaddr
, KM_USER0
);
2890 err
= pagecache_write_end(NULL
, mapping
, 0, len
-1, len
-1,
2897 mark_inode_dirty(inode
);
2903 int page_symlink(struct inode
*inode
, const char *symname
, int len
)
2905 return __page_symlink(inode
, symname
, len
,
2906 !(mapping_gfp_mask(inode
->i_mapping
) & __GFP_FS
));
2909 const struct inode_operations page_symlink_inode_operations
= {
2910 .readlink
= generic_readlink
,
2911 .follow_link
= page_follow_link_light
,
2912 .put_link
= page_put_link
,
2915 EXPORT_SYMBOL(user_path_at
);
2916 EXPORT_SYMBOL(follow_down
);
2917 EXPORT_SYMBOL(follow_up
);
2918 EXPORT_SYMBOL(get_write_access
); /* binfmt_aout */
2919 EXPORT_SYMBOL(getname
);
2920 EXPORT_SYMBOL(lock_rename
);
2921 EXPORT_SYMBOL(lookup_one_len
);
2922 EXPORT_SYMBOL(page_follow_link_light
);
2923 EXPORT_SYMBOL(page_put_link
);
2924 EXPORT_SYMBOL(page_readlink
);
2925 EXPORT_SYMBOL(__page_symlink
);
2926 EXPORT_SYMBOL(page_symlink
);
2927 EXPORT_SYMBOL(page_symlink_inode_operations
);
2928 EXPORT_SYMBOL(path_lookup
);
2929 EXPORT_SYMBOL(kern_path
);
2930 EXPORT_SYMBOL(vfs_path_lookup
);
2931 EXPORT_SYMBOL(inode_permission
);
2932 EXPORT_SYMBOL(file_permission
);
2933 EXPORT_SYMBOL(unlock_rename
);
2934 EXPORT_SYMBOL(vfs_create
);
2935 EXPORT_SYMBOL(vfs_follow_link
);
2936 EXPORT_SYMBOL(vfs_link
);
2937 EXPORT_SYMBOL(vfs_mkdir
);
2938 EXPORT_SYMBOL(vfs_mknod
);
2939 EXPORT_SYMBOL(generic_permission
);
2940 EXPORT_SYMBOL(vfs_readlink
);
2941 EXPORT_SYMBOL(vfs_rename
);
2942 EXPORT_SYMBOL(vfs_rmdir
);
2943 EXPORT_SYMBOL(vfs_symlink
);
2944 EXPORT_SYMBOL(vfs_unlink
);
2945 EXPORT_SYMBOL(dentry_unhash
);
2946 EXPORT_SYMBOL(generic_readlink
);