4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/string.h>
9 #include <linux/file.h>
10 #include <linux/fdtable.h>
11 #include <linux/fsnotify.h>
12 #include <linux/module.h>
13 #include <linux/tty.h>
14 #include <linux/namei.h>
15 #include <linux/backing-dev.h>
16 #include <linux/capability.h>
17 #include <linux/securebits.h>
18 #include <linux/security.h>
19 #include <linux/mount.h>
20 #include <linux/fcntl.h>
21 #include <linux/slab.h>
22 #include <asm/uaccess.h>
24 #include <linux/personality.h>
25 #include <linux/pagemap.h>
26 #include <linux/syscalls.h>
27 #include <linux/rcupdate.h>
28 #include <linux/audit.h>
29 #include <linux/falloc.h>
30 #include <linux/fs_struct.h>
31 #include <linux/ima.h>
32 #include <linux/dnotify.h>
33 #include <linux/compat.h>
37 int do_truncate(struct dentry
*dentry
, loff_t length
, unsigned int time_attrs
,
41 struct iattr newattrs
;
43 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
47 newattrs
.ia_size
= length
;
48 newattrs
.ia_valid
= ATTR_SIZE
| time_attrs
;
50 newattrs
.ia_file
= filp
;
51 newattrs
.ia_valid
|= ATTR_FILE
;
54 /* Remove suid, sgid, and file capabilities on truncate too */
55 ret
= dentry_needs_remove_privs(dentry
);
59 newattrs
.ia_valid
|= ret
| ATTR_FORCE
;
61 inode_lock(dentry
->d_inode
);
62 /* Note any delegations or leases have already been broken: */
63 ret
= notify_change(dentry
, &newattrs
, NULL
);
64 inode_unlock(dentry
->d_inode
);
68 long vfs_truncate(const struct path
*path
, loff_t length
)
71 struct dentry
*upperdentry
;
74 inode
= path
->dentry
->d_inode
;
76 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
77 if (S_ISDIR(inode
->i_mode
))
79 if (!S_ISREG(inode
->i_mode
))
82 error
= mnt_want_write(path
->mnt
);
86 error
= inode_permission(inode
, MAY_WRITE
);
88 goto mnt_drop_write_and_out
;
92 goto mnt_drop_write_and_out
;
95 * If this is an overlayfs then do as if opening the file so we get
96 * write access on the upper inode, not on the overlay inode. For
97 * non-overlay filesystems d_real() is an identity function.
99 upperdentry
= d_real(path
->dentry
, NULL
, O_WRONLY
);
100 error
= PTR_ERR(upperdentry
);
101 if (IS_ERR(upperdentry
))
102 goto mnt_drop_write_and_out
;
104 error
= get_write_access(upperdentry
->d_inode
);
106 goto mnt_drop_write_and_out
;
109 * Make sure that there are no leases. get_write_access() protects
110 * against the truncate racing with a lease-granting setlease().
112 error
= break_lease(inode
, O_WRONLY
);
114 goto put_write_and_out
;
116 error
= locks_verify_truncate(inode
, NULL
, length
);
118 error
= security_path_truncate(path
);
120 error
= do_truncate(path
->dentry
, length
, 0, NULL
);
123 put_write_access(upperdentry
->d_inode
);
124 mnt_drop_write_and_out
:
125 mnt_drop_write(path
->mnt
);
129 EXPORT_SYMBOL_GPL(vfs_truncate
);
131 static long do_sys_truncate(const char __user
*pathname
, loff_t length
)
133 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
137 if (length
< 0) /* sorry, but loff_t says... */
141 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
143 error
= vfs_truncate(&path
, length
);
146 if (retry_estale(error
, lookup_flags
)) {
147 lookup_flags
|= LOOKUP_REVAL
;
153 SYSCALL_DEFINE2(truncate
, const char __user
*, path
, long, length
)
155 return do_sys_truncate(path
, length
);
159 COMPAT_SYSCALL_DEFINE2(truncate
, const char __user
*, path
, compat_off_t
, length
)
161 return do_sys_truncate(path
, length
);
165 static long do_sys_ftruncate(unsigned int fd
, loff_t length
, int small
)
168 struct dentry
*dentry
;
180 /* explicitly opened as large or we are on 64-bit box */
181 if (f
.file
->f_flags
& O_LARGEFILE
)
184 dentry
= f
.file
->f_path
.dentry
;
185 inode
= dentry
->d_inode
;
187 if (!S_ISREG(inode
->i_mode
) || !(f
.file
->f_mode
& FMODE_WRITE
))
191 /* Cannot ftruncate over 2^31 bytes without large file support */
192 if (small
&& length
> MAX_NON_LFS
)
196 if (IS_APPEND(inode
))
199 sb_start_write(inode
->i_sb
);
200 error
= locks_verify_truncate(inode
, f
.file
, length
);
202 error
= security_path_truncate(&f
.file
->f_path
);
204 error
= do_truncate(dentry
, length
, ATTR_MTIME
|ATTR_CTIME
, f
.file
);
205 sb_end_write(inode
->i_sb
);
212 SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, unsigned long, length
)
214 return do_sys_ftruncate(fd
, length
, 1);
218 COMPAT_SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, compat_ulong_t
, length
)
220 return do_sys_ftruncate(fd
, length
, 1);
224 /* LFS versions of truncate are only needed on 32 bit machines */
225 #if BITS_PER_LONG == 32
226 SYSCALL_DEFINE2(truncate64
, const char __user
*, path
, loff_t
, length
)
228 return do_sys_truncate(path
, length
);
231 SYSCALL_DEFINE2(ftruncate64
, unsigned int, fd
, loff_t
, length
)
233 return do_sys_ftruncate(fd
, length
, 0);
235 #endif /* BITS_PER_LONG == 32 */
238 int vfs_fallocate(struct file
*file
, int mode
, loff_t offset
, loff_t len
)
240 struct inode
*inode
= file_inode(file
);
243 if (offset
< 0 || len
<= 0)
246 /* Return error if mode is not supported */
247 if (mode
& ~FALLOC_FL_SUPPORTED_MASK
)
250 /* Punch hole and zero range are mutually exclusive */
251 if ((mode
& (FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_ZERO_RANGE
)) ==
252 (FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_ZERO_RANGE
))
255 /* Punch hole must have keep size set */
256 if ((mode
& FALLOC_FL_PUNCH_HOLE
) &&
257 !(mode
& FALLOC_FL_KEEP_SIZE
))
260 /* Collapse range should only be used exclusively. */
261 if ((mode
& FALLOC_FL_COLLAPSE_RANGE
) &&
262 (mode
& ~FALLOC_FL_COLLAPSE_RANGE
))
265 /* Insert range should only be used exclusively. */
266 if ((mode
& FALLOC_FL_INSERT_RANGE
) &&
267 (mode
& ~FALLOC_FL_INSERT_RANGE
))
270 if (!(file
->f_mode
& FMODE_WRITE
))
274 * We can only allow pure fallocate on append only files
276 if ((mode
& ~FALLOC_FL_KEEP_SIZE
) && IS_APPEND(inode
))
279 if (IS_IMMUTABLE(inode
))
283 * We cannot allow any fallocate operation on an active swapfile
285 if (IS_SWAPFILE(inode
))
289 * Revalidate the write permissions, in case security policy has
290 * changed since the files were opened.
292 ret
= security_file_permission(file
, MAY_WRITE
);
296 if (S_ISFIFO(inode
->i_mode
))
300 * Let individual file system decide if it supports preallocation
301 * for directories or not.
303 if (!S_ISREG(inode
->i_mode
) && !S_ISDIR(inode
->i_mode
))
306 /* Check for wrap through zero too */
307 if (((offset
+ len
) > inode
->i_sb
->s_maxbytes
) || ((offset
+ len
) < 0))
310 if (!file
->f_op
->fallocate
)
313 sb_start_write(inode
->i_sb
);
314 ret
= file
->f_op
->fallocate(file
, mode
, offset
, len
);
317 * Create inotify and fanotify events.
319 * To keep the logic simple always create events if fallocate succeeds.
320 * This implies that events are even created if the file size remains
321 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
324 fsnotify_modify(file
);
326 sb_end_write(inode
->i_sb
);
329 EXPORT_SYMBOL_GPL(vfs_fallocate
);
331 SYSCALL_DEFINE4(fallocate
, int, fd
, int, mode
, loff_t
, offset
, loff_t
, len
)
333 struct fd f
= fdget(fd
);
337 error
= vfs_fallocate(f
.file
, mode
, offset
, len
);
344 * access() needs to use the real uid/gid, not the effective uid/gid.
345 * We do this by temporarily clearing all FS-related capabilities and
346 * switching the fsuid/fsgid around to the real ones.
348 SYSCALL_DEFINE3(faccessat
, int, dfd
, const char __user
*, filename
, int, mode
)
350 const struct cred
*old_cred
;
351 struct cred
*override_cred
;
355 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
357 if (mode
& ~S_IRWXO
) /* where's F_OK, X_OK, W_OK, R_OK? */
360 override_cred
= prepare_creds();
364 override_cred
->fsuid
= override_cred
->uid
;
365 override_cred
->fsgid
= override_cred
->gid
;
367 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
368 /* Clear the capabilities if we switch to a non-root user */
369 kuid_t root_uid
= make_kuid(override_cred
->user_ns
, 0);
370 if (!uid_eq(override_cred
->uid
, root_uid
))
371 cap_clear(override_cred
->cap_effective
);
373 override_cred
->cap_effective
=
374 override_cred
->cap_permitted
;
377 old_cred
= override_creds(override_cred
);
379 res
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
383 inode
= d_backing_inode(path
.dentry
);
385 if ((mode
& MAY_EXEC
) && S_ISREG(inode
->i_mode
)) {
387 * MAY_EXEC on regular files is denied if the fs is mounted
388 * with the "noexec" flag.
391 if (path_noexec(&path
))
392 goto out_path_release
;
395 res
= inode_permission(inode
, mode
| MAY_ACCESS
);
396 /* SuS v2 requires we report a read only fs too */
397 if (res
|| !(mode
& S_IWOTH
) || special_file(inode
->i_mode
))
398 goto out_path_release
;
400 * This is a rare case where using __mnt_is_readonly()
401 * is OK without a mnt_want/drop_write() pair. Since
402 * no actual write to the fs is performed here, we do
403 * not need to telegraph to that to anyone.
405 * By doing this, we accept that this access is
406 * inherently racy and know that the fs may change
407 * state before we even see this result.
409 if (__mnt_is_readonly(path
.mnt
))
414 if (retry_estale(res
, lookup_flags
)) {
415 lookup_flags
|= LOOKUP_REVAL
;
419 revert_creds(old_cred
);
420 put_cred(override_cred
);
424 SYSCALL_DEFINE2(access
, const char __user
*, filename
, int, mode
)
426 return sys_faccessat(AT_FDCWD
, filename
, mode
);
429 SYSCALL_DEFINE1(chdir
, const char __user
*, filename
)
433 unsigned int lookup_flags
= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
435 error
= user_path_at(AT_FDCWD
, filename
, lookup_flags
, &path
);
439 error
= inode_permission(path
.dentry
->d_inode
, MAY_EXEC
| MAY_CHDIR
);
443 set_fs_pwd(current
->fs
, &path
);
447 if (retry_estale(error
, lookup_flags
)) {
448 lookup_flags
|= LOOKUP_REVAL
;
455 SYSCALL_DEFINE1(fchdir
, unsigned int, fd
)
457 struct fd f
= fdget_raw(fd
);
465 inode
= file_inode(f
.file
);
468 if (!S_ISDIR(inode
->i_mode
))
471 error
= inode_permission(inode
, MAY_EXEC
| MAY_CHDIR
);
473 set_fs_pwd(current
->fs
, &f
.file
->f_path
);
480 SYSCALL_DEFINE1(chroot
, const char __user
*, filename
)
484 unsigned int lookup_flags
= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
486 error
= user_path_at(AT_FDCWD
, filename
, lookup_flags
, &path
);
490 error
= inode_permission(path
.dentry
->d_inode
, MAY_EXEC
| MAY_CHDIR
);
495 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT
))
497 error
= security_path_chroot(&path
);
501 set_fs_root(current
->fs
, &path
);
505 if (retry_estale(error
, lookup_flags
)) {
506 lookup_flags
|= LOOKUP_REVAL
;
513 static int chmod_common(const struct path
*path
, umode_t mode
)
515 struct inode
*inode
= path
->dentry
->d_inode
;
516 struct inode
*delegated_inode
= NULL
;
517 struct iattr newattrs
;
520 error
= mnt_want_write(path
->mnt
);
525 error
= security_path_chmod(path
, mode
);
528 newattrs
.ia_mode
= (mode
& S_IALLUGO
) | (inode
->i_mode
& ~S_IALLUGO
);
529 newattrs
.ia_valid
= ATTR_MODE
| ATTR_CTIME
;
530 error
= notify_change(path
->dentry
, &newattrs
, &delegated_inode
);
533 if (delegated_inode
) {
534 error
= break_deleg_wait(&delegated_inode
);
538 mnt_drop_write(path
->mnt
);
542 SYSCALL_DEFINE2(fchmod
, unsigned int, fd
, umode_t
, mode
)
544 struct fd f
= fdget(fd
);
549 err
= chmod_common(&f
.file
->f_path
, mode
);
555 SYSCALL_DEFINE3(fchmodat
, int, dfd
, const char __user
*, filename
, umode_t
, mode
)
559 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
561 error
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
563 error
= chmod_common(&path
, mode
);
565 if (retry_estale(error
, lookup_flags
)) {
566 lookup_flags
|= LOOKUP_REVAL
;
573 SYSCALL_DEFINE2(chmod
, const char __user
*, filename
, umode_t
, mode
)
575 return sys_fchmodat(AT_FDCWD
, filename
, mode
);
578 static int chown_common(const struct path
*path
, uid_t user
, gid_t group
)
580 struct inode
*inode
= path
->dentry
->d_inode
;
581 struct inode
*delegated_inode
= NULL
;
583 struct iattr newattrs
;
587 uid
= make_kuid(current_user_ns(), user
);
588 gid
= make_kgid(current_user_ns(), group
);
591 newattrs
.ia_valid
= ATTR_CTIME
;
592 if (user
!= (uid_t
) -1) {
595 newattrs
.ia_valid
|= ATTR_UID
;
596 newattrs
.ia_uid
= uid
;
598 if (group
!= (gid_t
) -1) {
601 newattrs
.ia_valid
|= ATTR_GID
;
602 newattrs
.ia_gid
= gid
;
604 if (!S_ISDIR(inode
->i_mode
))
606 ATTR_KILL_SUID
| ATTR_KILL_SGID
| ATTR_KILL_PRIV
;
608 error
= security_path_chown(path
, uid
, gid
);
610 error
= notify_change(path
->dentry
, &newattrs
, &delegated_inode
);
612 if (delegated_inode
) {
613 error
= break_deleg_wait(&delegated_inode
);
620 SYSCALL_DEFINE5(fchownat
, int, dfd
, const char __user
*, filename
, uid_t
, user
,
621 gid_t
, group
, int, flag
)
627 if ((flag
& ~(AT_SYMLINK_NOFOLLOW
| AT_EMPTY_PATH
)) != 0)
630 lookup_flags
= (flag
& AT_SYMLINK_NOFOLLOW
) ? 0 : LOOKUP_FOLLOW
;
631 if (flag
& AT_EMPTY_PATH
)
632 lookup_flags
|= LOOKUP_EMPTY
;
634 error
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
637 error
= mnt_want_write(path
.mnt
);
640 error
= chown_common(&path
, user
, group
);
641 mnt_drop_write(path
.mnt
);
644 if (retry_estale(error
, lookup_flags
)) {
645 lookup_flags
|= LOOKUP_REVAL
;
652 SYSCALL_DEFINE3(chown
, const char __user
*, filename
, uid_t
, user
, gid_t
, group
)
654 return sys_fchownat(AT_FDCWD
, filename
, user
, group
, 0);
657 SYSCALL_DEFINE3(lchown
, const char __user
*, filename
, uid_t
, user
, gid_t
, group
)
659 return sys_fchownat(AT_FDCWD
, filename
, user
, group
,
660 AT_SYMLINK_NOFOLLOW
);
663 SYSCALL_DEFINE3(fchown
, unsigned int, fd
, uid_t
, user
, gid_t
, group
)
665 struct fd f
= fdget(fd
);
671 error
= mnt_want_write_file(f
.file
);
675 error
= chown_common(&f
.file
->f_path
, user
, group
);
676 mnt_drop_write_file(f
.file
);
683 int open_check_o_direct(struct file
*f
)
685 /* NB: we're sure to have correct a_ops only after f_op->open */
686 if (f
->f_flags
& O_DIRECT
) {
687 if (!f
->f_mapping
->a_ops
|| !f
->f_mapping
->a_ops
->direct_IO
)
693 static int do_dentry_open(struct file
*f
,
695 int (*open
)(struct inode
*, struct file
*),
696 const struct cred
*cred
)
698 static const struct file_operations empty_fops
= {};
701 f
->f_mode
= OPEN_FMODE(f
->f_flags
) | FMODE_LSEEK
|
702 FMODE_PREAD
| FMODE_PWRITE
;
704 path_get(&f
->f_path
);
706 f
->f_mapping
= inode
->i_mapping
;
708 if (unlikely(f
->f_flags
& O_PATH
)) {
709 f
->f_mode
= FMODE_PATH
;
710 f
->f_op
= &empty_fops
;
714 if (f
->f_mode
& FMODE_WRITE
&& !special_file(inode
->i_mode
)) {
715 error
= get_write_access(inode
);
718 error
= __mnt_want_write(f
->f_path
.mnt
);
719 if (unlikely(error
)) {
720 put_write_access(inode
);
723 f
->f_mode
|= FMODE_WRITER
;
726 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
727 if (S_ISREG(inode
->i_mode
) || S_ISDIR(inode
->i_mode
))
728 f
->f_mode
|= FMODE_ATOMIC_POS
;
730 f
->f_op
= fops_get(inode
->i_fop
);
731 if (unlikely(WARN_ON(!f
->f_op
))) {
736 error
= security_file_open(f
, cred
);
740 error
= break_lease(locks_inode(f
), f
->f_flags
);
745 open
= f
->f_op
->open
;
747 error
= open(inode
, f
);
751 if ((f
->f_mode
& (FMODE_READ
| FMODE_WRITE
)) == FMODE_READ
)
752 i_readcount_inc(inode
);
753 if ((f
->f_mode
& FMODE_READ
) &&
754 likely(f
->f_op
->read
|| f
->f_op
->read_iter
))
755 f
->f_mode
|= FMODE_CAN_READ
;
756 if ((f
->f_mode
& FMODE_WRITE
) &&
757 likely(f
->f_op
->write
|| f
->f_op
->write_iter
))
758 f
->f_mode
|= FMODE_CAN_WRITE
;
760 f
->f_flags
&= ~(O_CREAT
| O_EXCL
| O_NOCTTY
| O_TRUNC
);
762 file_ra_state_init(&f
->f_ra
, f
->f_mapping
->host
->i_mapping
);
768 if (f
->f_mode
& FMODE_WRITER
) {
769 put_write_access(inode
);
770 __mnt_drop_write(f
->f_path
.mnt
);
773 path_put(&f
->f_path
);
774 f
->f_path
.mnt
= NULL
;
775 f
->f_path
.dentry
= NULL
;
781 * finish_open - finish opening a file
782 * @file: file pointer
783 * @dentry: pointer to dentry
784 * @open: open callback
785 * @opened: state of open
787 * This can be used to finish opening a file passed to i_op->atomic_open().
789 * If the open callback is set to NULL, then the standard f_op->open()
790 * filesystem callback is substituted.
792 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
793 * the return value of d_splice_alias(), then the caller needs to perform dput()
794 * on it after finish_open().
796 * On successful return @file is a fully instantiated open file. After this, if
797 * an error occurs in ->atomic_open(), it needs to clean up with fput().
799 * Returns zero on success or -errno if the open failed.
801 int finish_open(struct file
*file
, struct dentry
*dentry
,
802 int (*open
)(struct inode
*, struct file
*),
806 BUG_ON(*opened
& FILE_OPENED
); /* once it's opened, it's opened */
808 file
->f_path
.dentry
= dentry
;
809 error
= do_dentry_open(file
, d_backing_inode(dentry
), open
,
812 *opened
|= FILE_OPENED
;
816 EXPORT_SYMBOL(finish_open
);
819 * finish_no_open - finish ->atomic_open() without opening the file
821 * @file: file pointer
822 * @dentry: dentry or NULL (as returned from ->lookup())
824 * This can be used to set the result of a successful lookup in ->atomic_open().
826 * NB: unlike finish_open() this function does consume the dentry reference and
827 * the caller need not dput() it.
829 * Returns "1" which must be the return value of ->atomic_open() after having
830 * called this function.
832 int finish_no_open(struct file
*file
, struct dentry
*dentry
)
834 file
->f_path
.dentry
= dentry
;
837 EXPORT_SYMBOL(finish_no_open
);
839 char *file_path(struct file
*filp
, char *buf
, int buflen
)
841 return d_path(&filp
->f_path
, buf
, buflen
);
843 EXPORT_SYMBOL(file_path
);
846 * vfs_open - open the file at the given path
847 * @path: path to open
848 * @file: newly allocated file with f_flag initialized
849 * @cred: credentials to use
851 int vfs_open(const struct path
*path
, struct file
*file
,
852 const struct cred
*cred
)
854 struct dentry
*dentry
= d_real(path
->dentry
, NULL
, file
->f_flags
);
857 return PTR_ERR(dentry
);
859 file
->f_path
= *path
;
860 return do_dentry_open(file
, d_backing_inode(dentry
), NULL
, cred
);
863 struct file
*dentry_open(const struct path
*path
, int flags
,
864 const struct cred
*cred
)
869 validate_creds(cred
);
871 /* We must always pass in a valid mount pointer. */
874 f
= get_empty_filp();
877 error
= vfs_open(path
, f
, cred
);
879 /* from now on we need fput() to dispose of f */
880 error
= open_check_o_direct(f
);
892 EXPORT_SYMBOL(dentry_open
);
894 static inline int build_open_flags(int flags
, umode_t mode
, struct open_flags
*op
)
896 int lookup_flags
= 0;
897 int acc_mode
= ACC_MODE(flags
);
899 if (flags
& (O_CREAT
| __O_TMPFILE
))
900 op
->mode
= (mode
& S_IALLUGO
) | S_IFREG
;
904 /* Must never be set by userspace */
905 flags
&= ~FMODE_NONOTIFY
& ~O_CLOEXEC
;
908 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
909 * check for O_DSYNC if the need any syncing at all we enforce it's
910 * always set instead of having to deal with possibly weird behaviour
911 * for malicious applications setting only __O_SYNC.
913 if (flags
& __O_SYNC
)
916 if (flags
& __O_TMPFILE
) {
917 if ((flags
& O_TMPFILE_MASK
) != O_TMPFILE
)
919 if (!(acc_mode
& MAY_WRITE
))
921 } else if (flags
& O_PATH
) {
923 * If we have O_PATH in the open flag. Then we
924 * cannot have anything other than the below set of flags
926 flags
&= O_DIRECTORY
| O_NOFOLLOW
| O_PATH
;
930 op
->open_flag
= flags
;
932 /* O_TRUNC implies we need access checks for write permissions */
934 acc_mode
|= MAY_WRITE
;
936 /* Allow the LSM permission hook to distinguish append
937 access from general write access. */
938 if (flags
& O_APPEND
)
939 acc_mode
|= MAY_APPEND
;
941 op
->acc_mode
= acc_mode
;
943 op
->intent
= flags
& O_PATH
? 0 : LOOKUP_OPEN
;
945 if (flags
& O_CREAT
) {
946 op
->intent
|= LOOKUP_CREATE
;
948 op
->intent
|= LOOKUP_EXCL
;
951 if (flags
& O_DIRECTORY
)
952 lookup_flags
|= LOOKUP_DIRECTORY
;
953 if (!(flags
& O_NOFOLLOW
))
954 lookup_flags
|= LOOKUP_FOLLOW
;
955 op
->lookup_flags
= lookup_flags
;
960 * file_open_name - open file and return file pointer
962 * @name: struct filename containing path to open
963 * @flags: open flags as per the open(2) second argument
964 * @mode: mode for the new file if O_CREAT is set, else ignored
966 * This is the helper to open a file from kernelspace if you really
967 * have to. But in generally you should not do this, so please move
968 * along, nothing to see here..
970 struct file
*file_open_name(struct filename
*name
, int flags
, umode_t mode
)
972 struct open_flags op
;
973 int err
= build_open_flags(flags
, mode
, &op
);
974 return err
? ERR_PTR(err
) : do_filp_open(AT_FDCWD
, name
, &op
);
978 * filp_open - open file and return file pointer
980 * @filename: path to open
981 * @flags: open flags as per the open(2) second argument
982 * @mode: mode for the new file if O_CREAT is set, else ignored
984 * This is the helper to open a file from kernelspace if you really
985 * have to. But in generally you should not do this, so please move
986 * along, nothing to see here..
988 struct file
*filp_open(const char *filename
, int flags
, umode_t mode
)
990 struct filename
*name
= getname_kernel(filename
);
991 struct file
*file
= ERR_CAST(name
);
994 file
= file_open_name(name
, flags
, mode
);
999 EXPORT_SYMBOL(filp_open
);
1001 struct file
*file_open_root(struct dentry
*dentry
, struct vfsmount
*mnt
,
1002 const char *filename
, int flags
, umode_t mode
)
1004 struct open_flags op
;
1005 int err
= build_open_flags(flags
, mode
, &op
);
1007 return ERR_PTR(err
);
1008 return do_file_open_root(dentry
, mnt
, filename
, &op
);
1010 EXPORT_SYMBOL(file_open_root
);
1012 struct file
*filp_clone_open(struct file
*oldfile
)
1017 file
= get_empty_filp();
1021 file
->f_flags
= oldfile
->f_flags
;
1022 retval
= vfs_open(&oldfile
->f_path
, file
, oldfile
->f_cred
);
1025 return ERR_PTR(retval
);
1030 EXPORT_SYMBOL(filp_clone_open
);
1032 long do_sys_open(int dfd
, const char __user
*filename
, int flags
, umode_t mode
)
1034 struct open_flags op
;
1035 int fd
= build_open_flags(flags
, mode
, &op
);
1036 struct filename
*tmp
;
1041 tmp
= getname(filename
);
1043 return PTR_ERR(tmp
);
1045 fd
= get_unused_fd_flags(flags
);
1047 struct file
*f
= do_filp_open(dfd
, tmp
, &op
);
1060 SYSCALL_DEFINE3(open
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1062 if (force_o_largefile())
1063 flags
|= O_LARGEFILE
;
1065 return do_sys_open(AT_FDCWD
, filename
, flags
, mode
);
1068 SYSCALL_DEFINE4(openat
, int, dfd
, const char __user
*, filename
, int, flags
,
1071 if (force_o_largefile())
1072 flags
|= O_LARGEFILE
;
1074 return do_sys_open(dfd
, filename
, flags
, mode
);
1080 * For backward compatibility? Maybe this should be moved
1081 * into arch/i386 instead?
1083 SYSCALL_DEFINE2(creat
, const char __user
*, pathname
, umode_t
, mode
)
1085 return sys_open(pathname
, O_CREAT
| O_WRONLY
| O_TRUNC
, mode
);
1091 * "id" is the POSIX thread ID. We use the
1092 * files pointer for this..
1094 int filp_close(struct file
*filp
, fl_owner_t id
)
1098 if (!file_count(filp
)) {
1099 printk(KERN_ERR
"VFS: Close: file count is 0\n");
1103 if (filp
->f_op
->flush
)
1104 retval
= filp
->f_op
->flush(filp
, id
);
1106 if (likely(!(filp
->f_mode
& FMODE_PATH
))) {
1107 dnotify_flush(filp
, id
);
1108 locks_remove_posix(filp
, id
);
1114 EXPORT_SYMBOL(filp_close
);
1117 * Careful here! We test whether the file pointer is NULL before
1118 * releasing the fd. This ensures that one clone task can't release
1119 * an fd while another clone is opening it.
1121 SYSCALL_DEFINE1(close
, unsigned int, fd
)
1123 int retval
= __close_fd(current
->files
, fd
);
1125 /* can't restart close syscall because file table entry was cleared */
1126 if (unlikely(retval
== -ERESTARTSYS
||
1127 retval
== -ERESTARTNOINTR
||
1128 retval
== -ERESTARTNOHAND
||
1129 retval
== -ERESTART_RESTARTBLOCK
))
1134 EXPORT_SYMBOL(sys_close
);
1137 * This routine simulates a hangup on the tty, to arrange that users
1138 * are given clean terminals at login time.
1140 SYSCALL_DEFINE0(vhangup
)
1142 if (capable(CAP_SYS_TTY_CONFIG
)) {
1150 * Called when an inode is about to be open.
1151 * We use this to disallow opening large files on 32bit systems if
1152 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1153 * on this flag in sys_open.
1155 int generic_file_open(struct inode
* inode
, struct file
* filp
)
1157 if (!(filp
->f_flags
& O_LARGEFILE
) && i_size_read(inode
) > MAX_NON_LFS
)
1162 EXPORT_SYMBOL(generic_file_open
);
1165 * This is used by subsystems that don't want seekable
1166 * file descriptors. The function is not supposed to ever fail, the only
1167 * reason it returns an 'int' and not 'void' is so that it can be plugged
1168 * directly into file_operations structure.
1170 int nonseekable_open(struct inode
*inode
, struct file
*filp
)
1172 filp
->f_mode
&= ~(FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
);
1176 EXPORT_SYMBOL(nonseekable_open
);