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 <linux/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_truncate2(struct vfsmount
*mnt
, struct dentry
*dentry
, loff_t length
,
38 unsigned int time_attrs
, struct file
*filp
)
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_change2(mnt
, dentry
, &newattrs
, NULL
);
64 inode_unlock(dentry
->d_inode
);
67 int do_truncate(struct dentry
*dentry
, loff_t length
, unsigned int time_attrs
,
70 return do_truncate2(NULL
, dentry
, length
, time_attrs
, filp
);
73 long vfs_truncate(const struct path
*path
, loff_t length
)
77 struct dentry
*upperdentry
;
80 inode
= path
->dentry
->d_inode
;
83 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
84 if (S_ISDIR(inode
->i_mode
))
86 if (!S_ISREG(inode
->i_mode
))
89 error
= mnt_want_write(path
->mnt
);
93 error
= inode_permission2(mnt
, inode
, MAY_WRITE
);
95 goto mnt_drop_write_and_out
;
99 goto mnt_drop_write_and_out
;
102 * If this is an overlayfs then do as if opening the file so we get
103 * write access on the upper inode, not on the overlay inode. For
104 * non-overlay filesystems d_real() is an identity function.
106 upperdentry
= d_real(path
->dentry
, NULL
, O_WRONLY
, 0);
107 error
= PTR_ERR(upperdentry
);
108 if (IS_ERR(upperdentry
))
109 goto mnt_drop_write_and_out
;
111 error
= get_write_access(upperdentry
->d_inode
);
113 goto mnt_drop_write_and_out
;
116 * Make sure that there are no leases. get_write_access() protects
117 * against the truncate racing with a lease-granting setlease().
119 error
= break_lease(inode
, O_WRONLY
);
121 goto put_write_and_out
;
123 error
= locks_verify_truncate(inode
, NULL
, length
);
125 error
= security_path_truncate(path
);
127 error
= do_truncate2(mnt
, path
->dentry
, length
, 0, NULL
);
130 put_write_access(upperdentry
->d_inode
);
131 mnt_drop_write_and_out
:
132 mnt_drop_write(path
->mnt
);
136 EXPORT_SYMBOL_GPL(vfs_truncate
);
138 static long do_sys_truncate(const char __user
*pathname
, loff_t length
)
140 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
144 if (length
< 0) /* sorry, but loff_t says... */
148 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
150 error
= vfs_truncate(&path
, length
);
153 if (retry_estale(error
, lookup_flags
)) {
154 lookup_flags
|= LOOKUP_REVAL
;
160 SYSCALL_DEFINE2(truncate
, const char __user
*, path
, long, length
)
162 return do_sys_truncate(path
, length
);
166 COMPAT_SYSCALL_DEFINE2(truncate
, const char __user
*, path
, compat_off_t
, length
)
168 return do_sys_truncate(path
, length
);
172 static long do_sys_ftruncate(unsigned int fd
, loff_t length
, int small
)
175 struct dentry
*dentry
;
176 struct vfsmount
*mnt
;
188 /* explicitly opened as large or we are on 64-bit box */
189 if (f
.file
->f_flags
& O_LARGEFILE
)
192 dentry
= f
.file
->f_path
.dentry
;
193 mnt
= f
.file
->f_path
.mnt
;
194 inode
= dentry
->d_inode
;
196 if (!S_ISREG(inode
->i_mode
) || !(f
.file
->f_mode
& FMODE_WRITE
))
200 /* Cannot ftruncate over 2^31 bytes without large file support */
201 if (small
&& length
> MAX_NON_LFS
)
205 /* Check IS_APPEND on real upper inode */
206 if (IS_APPEND(file_inode(f
.file
)))
209 sb_start_write(inode
->i_sb
);
210 error
= locks_verify_truncate(inode
, f
.file
, length
);
212 error
= security_path_truncate(&f
.file
->f_path
);
214 error
= do_truncate2(mnt
, dentry
, length
, ATTR_MTIME
|ATTR_CTIME
, f
.file
);
215 sb_end_write(inode
->i_sb
);
222 SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, unsigned long, length
)
224 return do_sys_ftruncate(fd
, length
, 1);
228 COMPAT_SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, compat_ulong_t
, length
)
230 return do_sys_ftruncate(fd
, length
, 1);
234 /* LFS versions of truncate are only needed on 32 bit machines */
235 #if BITS_PER_LONG == 32
236 SYSCALL_DEFINE2(truncate64
, const char __user
*, path
, loff_t
, length
)
238 return do_sys_truncate(path
, length
);
241 SYSCALL_DEFINE2(ftruncate64
, unsigned int, fd
, loff_t
, length
)
243 return do_sys_ftruncate(fd
, length
, 0);
245 #endif /* BITS_PER_LONG == 32 */
248 int vfs_fallocate(struct file
*file
, int mode
, loff_t offset
, loff_t len
)
250 struct inode
*inode
= file_inode(file
);
253 if (offset
< 0 || len
<= 0)
256 /* Return error if mode is not supported */
257 if (mode
& ~FALLOC_FL_SUPPORTED_MASK
)
260 /* Punch hole and zero range are mutually exclusive */
261 if ((mode
& (FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_ZERO_RANGE
)) ==
262 (FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_ZERO_RANGE
))
265 /* Punch hole must have keep size set */
266 if ((mode
& FALLOC_FL_PUNCH_HOLE
) &&
267 !(mode
& FALLOC_FL_KEEP_SIZE
))
270 /* Collapse range should only be used exclusively. */
271 if ((mode
& FALLOC_FL_COLLAPSE_RANGE
) &&
272 (mode
& ~FALLOC_FL_COLLAPSE_RANGE
))
275 /* Insert range should only be used exclusively. */
276 if ((mode
& FALLOC_FL_INSERT_RANGE
) &&
277 (mode
& ~FALLOC_FL_INSERT_RANGE
))
280 /* Unshare range should only be used with allocate mode. */
281 if ((mode
& FALLOC_FL_UNSHARE_RANGE
) &&
282 (mode
& ~(FALLOC_FL_UNSHARE_RANGE
| FALLOC_FL_KEEP_SIZE
)))
285 if (!(file
->f_mode
& FMODE_WRITE
))
289 * We can only allow pure fallocate on append only files
291 if ((mode
& ~FALLOC_FL_KEEP_SIZE
) && IS_APPEND(inode
))
294 if (IS_IMMUTABLE(inode
))
298 * We cannot allow any fallocate operation on an active swapfile
300 if (IS_SWAPFILE(inode
))
304 * Revalidate the write permissions, in case security policy has
305 * changed since the files were opened.
307 ret
= security_file_permission(file
, MAY_WRITE
);
311 if (S_ISFIFO(inode
->i_mode
))
314 if (S_ISDIR(inode
->i_mode
))
317 if (!S_ISREG(inode
->i_mode
) && !S_ISBLK(inode
->i_mode
))
320 /* Check for wrap through zero too */
321 if (((offset
+ len
) > inode
->i_sb
->s_maxbytes
) || ((offset
+ len
) < 0))
324 if (!file
->f_op
->fallocate
)
327 file_start_write(file
);
328 ret
= file
->f_op
->fallocate(file
, mode
, offset
, len
);
331 * Create inotify and fanotify events.
333 * To keep the logic simple always create events if fallocate succeeds.
334 * This implies that events are even created if the file size remains
335 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
338 fsnotify_modify(file
);
340 file_end_write(file
);
343 EXPORT_SYMBOL_GPL(vfs_fallocate
);
345 SYSCALL_DEFINE4(fallocate
, int, fd
, int, mode
, loff_t
, offset
, loff_t
, len
)
347 struct fd f
= fdget(fd
);
351 error
= vfs_fallocate(f
.file
, mode
, offset
, len
);
358 * access() needs to use the real uid/gid, not the effective uid/gid.
359 * We do this by temporarily clearing all FS-related capabilities and
360 * switching the fsuid/fsgid around to the real ones.
362 SYSCALL_DEFINE3(faccessat
, int, dfd
, const char __user
*, filename
, int, mode
)
364 const struct cred
*old_cred
;
365 struct cred
*override_cred
;
368 struct vfsmount
*mnt
;
370 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
372 if (mode
& ~S_IRWXO
) /* where's F_OK, X_OK, W_OK, R_OK? */
375 override_cred
= prepare_creds();
379 override_cred
->fsuid
= override_cred
->uid
;
380 override_cred
->fsgid
= override_cred
->gid
;
382 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
383 /* Clear the capabilities if we switch to a non-root user */
384 kuid_t root_uid
= make_kuid(override_cred
->user_ns
, 0);
385 if (!uid_eq(override_cred
->uid
, root_uid
))
386 cap_clear(override_cred
->cap_effective
);
388 override_cred
->cap_effective
=
389 override_cred
->cap_permitted
;
392 old_cred
= override_creds(override_cred
);
394 res
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
398 inode
= d_backing_inode(path
.dentry
);
401 if ((mode
& MAY_EXEC
) && S_ISREG(inode
->i_mode
)) {
403 * MAY_EXEC on regular files is denied if the fs is mounted
404 * with the "noexec" flag.
407 if (path_noexec(&path
))
408 goto out_path_release
;
411 res
= inode_permission2(mnt
, inode
, mode
| MAY_ACCESS
);
412 /* SuS v2 requires we report a read only fs too */
413 if (res
|| !(mode
& S_IWOTH
) || special_file(inode
->i_mode
))
414 goto out_path_release
;
416 * This is a rare case where using __mnt_is_readonly()
417 * is OK without a mnt_want/drop_write() pair. Since
418 * no actual write to the fs is performed here, we do
419 * not need to telegraph to that to anyone.
421 * By doing this, we accept that this access is
422 * inherently racy and know that the fs may change
423 * state before we even see this result.
425 if (__mnt_is_readonly(path
.mnt
))
430 if (retry_estale(res
, lookup_flags
)) {
431 lookup_flags
|= LOOKUP_REVAL
;
435 revert_creds(old_cred
);
436 put_cred(override_cred
);
440 SYSCALL_DEFINE2(access
, const char __user
*, filename
, int, mode
)
442 return sys_faccessat(AT_FDCWD
, filename
, mode
);
445 SYSCALL_DEFINE1(chdir
, const char __user
*, filename
)
449 unsigned int lookup_flags
= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
451 error
= user_path_at(AT_FDCWD
, filename
, lookup_flags
, &path
);
455 error
= inode_permission2(path
.mnt
, path
.dentry
->d_inode
, MAY_EXEC
| MAY_CHDIR
);
459 set_fs_pwd(current
->fs
, &path
);
463 if (retry_estale(error
, lookup_flags
)) {
464 lookup_flags
|= LOOKUP_REVAL
;
471 SYSCALL_DEFINE1(fchdir
, unsigned int, fd
)
473 struct fd f
= fdget_raw(fd
);
481 if (!d_can_lookup(f
.file
->f_path
.dentry
))
484 error
= inode_permission2(f
.file
->f_path
.mnt
, file_inode(f
.file
),
485 MAY_EXEC
| MAY_CHDIR
);
487 set_fs_pwd(current
->fs
, &f
.file
->f_path
);
494 SYSCALL_DEFINE1(chroot
, const char __user
*, filename
)
498 unsigned int lookup_flags
= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
500 error
= user_path_at(AT_FDCWD
, filename
, lookup_flags
, &path
);
504 error
= inode_permission2(path
.mnt
, path
.dentry
->d_inode
, MAY_EXEC
| MAY_CHDIR
);
509 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT
))
511 error
= security_path_chroot(&path
);
515 set_fs_root(current
->fs
, &path
);
519 if (retry_estale(error
, lookup_flags
)) {
520 lookup_flags
|= LOOKUP_REVAL
;
527 static int chmod_common(const struct path
*path
, umode_t mode
)
529 struct inode
*inode
= path
->dentry
->d_inode
;
530 struct inode
*delegated_inode
= NULL
;
531 struct iattr newattrs
;
534 error
= mnt_want_write(path
->mnt
);
539 error
= security_path_chmod(path
, mode
);
542 newattrs
.ia_mode
= (mode
& S_IALLUGO
) | (inode
->i_mode
& ~S_IALLUGO
);
543 newattrs
.ia_valid
= ATTR_MODE
| ATTR_CTIME
;
544 error
= notify_change2(path
->mnt
, path
->dentry
, &newattrs
, &delegated_inode
);
547 if (delegated_inode
) {
548 error
= break_deleg_wait(&delegated_inode
);
552 mnt_drop_write(path
->mnt
);
556 SYSCALL_DEFINE2(fchmod
, unsigned int, fd
, umode_t
, mode
)
558 struct fd f
= fdget(fd
);
563 err
= chmod_common(&f
.file
->f_path
, mode
);
569 SYSCALL_DEFINE3(fchmodat
, int, dfd
, const char __user
*, filename
, umode_t
, mode
)
573 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
575 error
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
577 error
= chmod_common(&path
, mode
);
579 if (retry_estale(error
, lookup_flags
)) {
580 lookup_flags
|= LOOKUP_REVAL
;
587 SYSCALL_DEFINE2(chmod
, const char __user
*, filename
, umode_t
, mode
)
589 return sys_fchmodat(AT_FDCWD
, filename
, mode
);
592 static int chown_common(const struct path
*path
, uid_t user
, gid_t group
)
594 struct inode
*inode
= path
->dentry
->d_inode
;
595 struct inode
*delegated_inode
= NULL
;
597 struct iattr newattrs
;
601 uid
= make_kuid(current_user_ns(), user
);
602 gid
= make_kgid(current_user_ns(), group
);
605 newattrs
.ia_valid
= ATTR_CTIME
;
606 if (user
!= (uid_t
) -1) {
609 newattrs
.ia_valid
|= ATTR_UID
;
610 newattrs
.ia_uid
= uid
;
612 if (group
!= (gid_t
) -1) {
615 newattrs
.ia_valid
|= ATTR_GID
;
616 newattrs
.ia_gid
= gid
;
618 if (!S_ISDIR(inode
->i_mode
))
620 ATTR_KILL_SUID
| ATTR_KILL_SGID
| ATTR_KILL_PRIV
;
622 error
= security_path_chown(path
, uid
, gid
);
624 error
= notify_change2(path
->mnt
, path
->dentry
, &newattrs
, &delegated_inode
);
626 if (delegated_inode
) {
627 error
= break_deleg_wait(&delegated_inode
);
634 SYSCALL_DEFINE5(fchownat
, int, dfd
, const char __user
*, filename
, uid_t
, user
,
635 gid_t
, group
, int, flag
)
641 if ((flag
& ~(AT_SYMLINK_NOFOLLOW
| AT_EMPTY_PATH
)) != 0)
644 lookup_flags
= (flag
& AT_SYMLINK_NOFOLLOW
) ? 0 : LOOKUP_FOLLOW
;
645 if (flag
& AT_EMPTY_PATH
)
646 lookup_flags
|= LOOKUP_EMPTY
;
648 error
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
651 error
= mnt_want_write(path
.mnt
);
654 error
= chown_common(&path
, user
, group
);
655 mnt_drop_write(path
.mnt
);
658 if (retry_estale(error
, lookup_flags
)) {
659 lookup_flags
|= LOOKUP_REVAL
;
666 SYSCALL_DEFINE3(chown
, const char __user
*, filename
, uid_t
, user
, gid_t
, group
)
668 return sys_fchownat(AT_FDCWD
, filename
, user
, group
, 0);
671 SYSCALL_DEFINE3(lchown
, const char __user
*, filename
, uid_t
, user
, gid_t
, group
)
673 return sys_fchownat(AT_FDCWD
, filename
, user
, group
,
674 AT_SYMLINK_NOFOLLOW
);
677 SYSCALL_DEFINE3(fchown
, unsigned int, fd
, uid_t
, user
, gid_t
, group
)
679 struct fd f
= fdget(fd
);
685 error
= mnt_want_write_file_path(f
.file
);
689 error
= chown_common(&f
.file
->f_path
, user
, group
);
690 mnt_drop_write_file_path(f
.file
);
697 int open_check_o_direct(struct file
*f
)
699 /* NB: we're sure to have correct a_ops only after f_op->open */
700 if (f
->f_flags
& O_DIRECT
) {
701 if (!f
->f_mapping
->a_ops
|| !f
->f_mapping
->a_ops
->direct_IO
)
707 static int do_dentry_open(struct file
*f
,
709 int (*open
)(struct inode
*, struct file
*),
710 const struct cred
*cred
)
712 static const struct file_operations empty_fops
= {};
715 f
->f_mode
= OPEN_FMODE(f
->f_flags
) | FMODE_LSEEK
|
716 FMODE_PREAD
| FMODE_PWRITE
;
718 path_get(&f
->f_path
);
720 f
->f_mapping
= inode
->i_mapping
;
722 /* Ensure that we skip any errors that predate opening of the file */
723 f
->f_wb_err
= filemap_sample_wb_err(f
->f_mapping
);
725 if (unlikely(f
->f_flags
& O_PATH
)) {
726 f
->f_mode
= FMODE_PATH
;
727 f
->f_op
= &empty_fops
;
731 /* Any file opened for execve()/uselib() has to be a regular file. */
732 if (unlikely(f
->f_flags
& FMODE_EXEC
&& !S_ISREG(inode
->i_mode
))) {
737 if (f
->f_mode
& FMODE_WRITE
&& !special_file(inode
->i_mode
)) {
738 error
= get_write_access(inode
);
741 error
= __mnt_want_write(f
->f_path
.mnt
);
742 if (unlikely(error
)) {
743 put_write_access(inode
);
746 f
->f_mode
|= FMODE_WRITER
;
749 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
750 if (S_ISREG(inode
->i_mode
) || S_ISDIR(inode
->i_mode
))
751 f
->f_mode
|= FMODE_ATOMIC_POS
;
753 f
->f_op
= fops_get(inode
->i_fop
);
754 if (unlikely(WARN_ON(!f
->f_op
))) {
759 error
= security_file_open(f
, cred
);
763 error
= break_lease(locks_inode(f
), f
->f_flags
);
768 open
= f
->f_op
->open
;
770 error
= open(inode
, f
);
774 if ((f
->f_mode
& (FMODE_READ
| FMODE_WRITE
)) == FMODE_READ
)
775 i_readcount_inc(inode
);
776 if ((f
->f_mode
& FMODE_READ
) &&
777 likely(f
->f_op
->read
|| f
->f_op
->read_iter
))
778 f
->f_mode
|= FMODE_CAN_READ
;
779 if ((f
->f_mode
& FMODE_WRITE
) &&
780 likely(f
->f_op
->write
|| f
->f_op
->write_iter
))
781 f
->f_mode
|= FMODE_CAN_WRITE
;
783 f
->f_write_hint
= WRITE_LIFE_NOT_SET
;
784 f
->f_flags
&= ~(O_CREAT
| O_EXCL
| O_NOCTTY
| O_TRUNC
);
786 file_ra_state_init(&f
->f_ra
, f
->f_mapping
->host
->i_mapping
);
792 if (f
->f_mode
& FMODE_WRITER
) {
793 put_write_access(inode
);
794 __mnt_drop_write(f
->f_path
.mnt
);
797 path_put(&f
->f_path
);
798 f
->f_path
.mnt
= NULL
;
799 f
->f_path
.dentry
= NULL
;
805 * finish_open - finish opening a file
806 * @file: file pointer
807 * @dentry: pointer to dentry
808 * @open: open callback
809 * @opened: state of open
811 * This can be used to finish opening a file passed to i_op->atomic_open().
813 * If the open callback is set to NULL, then the standard f_op->open()
814 * filesystem callback is substituted.
816 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
817 * the return value of d_splice_alias(), then the caller needs to perform dput()
818 * on it after finish_open().
820 * On successful return @file is a fully instantiated open file. After this, if
821 * an error occurs in ->atomic_open(), it needs to clean up with fput().
823 * Returns zero on success or -errno if the open failed.
825 int finish_open(struct file
*file
, struct dentry
*dentry
,
826 int (*open
)(struct inode
*, struct file
*),
830 BUG_ON(*opened
& FILE_OPENED
); /* once it's opened, it's opened */
832 file
->f_path
.dentry
= dentry
;
833 error
= do_dentry_open(file
, d_backing_inode(dentry
), open
,
836 *opened
|= FILE_OPENED
;
840 EXPORT_SYMBOL(finish_open
);
843 * finish_no_open - finish ->atomic_open() without opening the file
845 * @file: file pointer
846 * @dentry: dentry or NULL (as returned from ->lookup())
848 * This can be used to set the result of a successful lookup in ->atomic_open().
850 * NB: unlike finish_open() this function does consume the dentry reference and
851 * the caller need not dput() it.
853 * Returns "1" which must be the return value of ->atomic_open() after having
854 * called this function.
856 int finish_no_open(struct file
*file
, struct dentry
*dentry
)
858 file
->f_path
.dentry
= dentry
;
861 EXPORT_SYMBOL(finish_no_open
);
863 char *file_path(struct file
*filp
, char *buf
, int buflen
)
865 return d_path(&filp
->f_path
, buf
, buflen
);
867 EXPORT_SYMBOL(file_path
);
870 * vfs_open - open the file at the given path
871 * @path: path to open
872 * @file: newly allocated file with f_flag initialized
873 * @cred: credentials to use
875 int vfs_open(const struct path
*path
, struct file
*file
,
876 const struct cred
*cred
)
878 struct dentry
*dentry
= d_real(path
->dentry
, NULL
, file
->f_flags
, 0);
881 return PTR_ERR(dentry
);
883 file
->f_path
= *path
;
884 return do_dentry_open(file
, d_backing_inode(dentry
), NULL
, cred
);
887 struct file
*dentry_open(const struct path
*path
, int flags
,
888 const struct cred
*cred
)
893 validate_creds(cred
);
895 /* We must always pass in a valid mount pointer. */
898 f
= get_empty_filp();
901 error
= vfs_open(path
, f
, cred
);
903 /* from now on we need fput() to dispose of f */
904 error
= open_check_o_direct(f
);
916 EXPORT_SYMBOL(dentry_open
);
918 static inline int build_open_flags(int flags
, umode_t mode
, struct open_flags
*op
)
920 int lookup_flags
= 0;
921 int acc_mode
= ACC_MODE(flags
);
924 * Clear out all open flags we don't know about so that we don't report
925 * them in fcntl(F_GETFD) or similar interfaces.
927 flags
&= VALID_OPEN_FLAGS
;
929 if (flags
& (O_CREAT
| __O_TMPFILE
))
930 op
->mode
= (mode
& S_IALLUGO
) | S_IFREG
;
934 /* Must never be set by userspace */
935 flags
&= ~FMODE_NONOTIFY
& ~O_CLOEXEC
;
938 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
939 * check for O_DSYNC if the need any syncing at all we enforce it's
940 * always set instead of having to deal with possibly weird behaviour
941 * for malicious applications setting only __O_SYNC.
943 if (flags
& __O_SYNC
)
946 if (flags
& __O_TMPFILE
) {
947 if ((flags
& O_TMPFILE_MASK
) != O_TMPFILE
)
949 if (!(acc_mode
& MAY_WRITE
))
951 } else if (flags
& O_PATH
) {
953 * If we have O_PATH in the open flag. Then we
954 * cannot have anything other than the below set of flags
956 flags
&= O_DIRECTORY
| O_NOFOLLOW
| O_PATH
;
960 op
->open_flag
= flags
;
962 /* O_TRUNC implies we need access checks for write permissions */
964 acc_mode
|= MAY_WRITE
;
966 /* Allow the LSM permission hook to distinguish append
967 access from general write access. */
968 if (flags
& O_APPEND
)
969 acc_mode
|= MAY_APPEND
;
971 op
->acc_mode
= acc_mode
;
973 op
->intent
= flags
& O_PATH
? 0 : LOOKUP_OPEN
;
975 if (flags
& O_CREAT
) {
976 op
->intent
|= LOOKUP_CREATE
;
978 op
->intent
|= LOOKUP_EXCL
;
981 if (flags
& O_DIRECTORY
)
982 lookup_flags
|= LOOKUP_DIRECTORY
;
983 if (!(flags
& O_NOFOLLOW
))
984 lookup_flags
|= LOOKUP_FOLLOW
;
985 op
->lookup_flags
= lookup_flags
;
990 * file_open_name - open file and return file pointer
992 * @name: struct filename containing path to open
993 * @flags: open flags as per the open(2) second argument
994 * @mode: mode for the new file if O_CREAT is set, else ignored
996 * This is the helper to open a file from kernelspace if you really
997 * have to. But in generally you should not do this, so please move
998 * along, nothing to see here..
1000 struct file
*file_open_name(struct filename
*name
, int flags
, umode_t mode
)
1002 struct open_flags op
;
1003 int err
= build_open_flags(flags
, mode
, &op
);
1004 return err
? ERR_PTR(err
) : do_filp_open(AT_FDCWD
, name
, &op
);
1008 * filp_open - open file and return file pointer
1010 * @filename: path to open
1011 * @flags: open flags as per the open(2) second argument
1012 * @mode: mode for the new file if O_CREAT is set, else ignored
1014 * This is the helper to open a file from kernelspace if you really
1015 * have to. But in generally you should not do this, so please move
1016 * along, nothing to see here..
1018 struct file
*filp_open(const char *filename
, int flags
, umode_t mode
)
1020 struct filename
*name
= getname_kernel(filename
);
1021 struct file
*file
= ERR_CAST(name
);
1023 if (!IS_ERR(name
)) {
1024 file
= file_open_name(name
, flags
, mode
);
1029 EXPORT_SYMBOL(filp_open
);
1031 struct file
*file_open_root(struct dentry
*dentry
, struct vfsmount
*mnt
,
1032 const char *filename
, int flags
, umode_t mode
)
1034 struct open_flags op
;
1035 int err
= build_open_flags(flags
, mode
, &op
);
1037 return ERR_PTR(err
);
1038 return do_file_open_root(dentry
, mnt
, filename
, &op
);
1040 EXPORT_SYMBOL(file_open_root
);
1042 struct file
*filp_clone_open(struct file
*oldfile
)
1047 file
= get_empty_filp();
1051 file
->f_flags
= oldfile
->f_flags
;
1052 retval
= vfs_open(&oldfile
->f_path
, file
, oldfile
->f_cred
);
1055 return ERR_PTR(retval
);
1060 EXPORT_SYMBOL(filp_clone_open
);
1062 long do_sys_open(int dfd
, const char __user
*filename
, int flags
, umode_t mode
)
1064 struct open_flags op
;
1065 int fd
= build_open_flags(flags
, mode
, &op
);
1066 struct filename
*tmp
;
1071 tmp
= getname(filename
);
1073 return PTR_ERR(tmp
);
1075 fd
= get_unused_fd_flags(flags
);
1077 struct file
*f
= do_filp_open(dfd
, tmp
, &op
);
1090 SYSCALL_DEFINE3(open
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1092 if (force_o_largefile())
1093 flags
|= O_LARGEFILE
;
1095 return do_sys_open(AT_FDCWD
, filename
, flags
, mode
);
1098 SYSCALL_DEFINE4(openat
, int, dfd
, const char __user
*, filename
, int, flags
,
1101 if (force_o_largefile())
1102 flags
|= O_LARGEFILE
;
1104 return do_sys_open(dfd
, filename
, flags
, mode
);
1107 #ifdef CONFIG_COMPAT
1109 * Exactly like sys_open(), except that it doesn't set the
1112 COMPAT_SYSCALL_DEFINE3(open
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1114 return do_sys_open(AT_FDCWD
, filename
, flags
, mode
);
1118 * Exactly like sys_openat(), except that it doesn't set the
1121 COMPAT_SYSCALL_DEFINE4(openat
, int, dfd
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1123 return do_sys_open(dfd
, filename
, flags
, mode
);
1130 * For backward compatibility? Maybe this should be moved
1131 * into arch/i386 instead?
1133 SYSCALL_DEFINE2(creat
, const char __user
*, pathname
, umode_t
, mode
)
1135 return sys_open(pathname
, O_CREAT
| O_WRONLY
| O_TRUNC
, mode
);
1141 * "id" is the POSIX thread ID. We use the
1142 * files pointer for this..
1144 int filp_close(struct file
*filp
, fl_owner_t id
)
1148 if (!file_count(filp
)) {
1149 printk(KERN_ERR
"VFS: Close: file count is 0\n");
1153 if (filp
->f_op
->flush
)
1154 retval
= filp
->f_op
->flush(filp
, id
);
1156 if (likely(!(filp
->f_mode
& FMODE_PATH
))) {
1157 dnotify_flush(filp
, id
);
1158 locks_remove_posix(filp
, id
);
1164 EXPORT_SYMBOL(filp_close
);
1167 * Careful here! We test whether the file pointer is NULL before
1168 * releasing the fd. This ensures that one clone task can't release
1169 * an fd while another clone is opening it.
1171 SYSCALL_DEFINE1(close
, unsigned int, fd
)
1173 int retval
= __close_fd(current
->files
, fd
);
1175 /* can't restart close syscall because file table entry was cleared */
1176 if (unlikely(retval
== -ERESTARTSYS
||
1177 retval
== -ERESTARTNOINTR
||
1178 retval
== -ERESTARTNOHAND
||
1179 retval
== -ERESTART_RESTARTBLOCK
))
1184 EXPORT_SYMBOL(sys_close
);
1187 * This routine simulates a hangup on the tty, to arrange that users
1188 * are given clean terminals at login time.
1190 SYSCALL_DEFINE0(vhangup
)
1192 if (capable(CAP_SYS_TTY_CONFIG
)) {
1200 * Called when an inode is about to be open.
1201 * We use this to disallow opening large files on 32bit systems if
1202 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1203 * on this flag in sys_open.
1205 int generic_file_open(struct inode
* inode
, struct file
* filp
)
1207 if (!(filp
->f_flags
& O_LARGEFILE
) && i_size_read(inode
) > MAX_NON_LFS
)
1212 EXPORT_SYMBOL(generic_file_open
);
1215 * This is used by subsystems that don't want seekable
1216 * file descriptors. The function is not supposed to ever fail, the only
1217 * reason it returns an 'int' and not 'void' is so that it can be plugged
1218 * directly into file_operations structure.
1220 int nonseekable_open(struct inode
*inode
, struct file
*filp
)
1222 filp
->f_mode
&= ~(FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
);
1226 EXPORT_SYMBOL(nonseekable_open
);