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/quotaops.h>
12 #include <linux/fsnotify.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/tty.h>
16 #include <linux/namei.h>
17 #include <linux/backing-dev.h>
18 #include <linux/capability.h>
19 #include <linux/securebits.h>
20 #include <linux/security.h>
21 #include <linux/mount.h>
22 #include <linux/vfs.h>
23 #include <linux/fcntl.h>
24 #include <asm/uaccess.h>
26 #include <linux/personality.h>
27 #include <linux/pagemap.h>
28 #include <linux/syscalls.h>
29 #include <linux/rcupdate.h>
30 #include <linux/audit.h>
31 #include <linux/falloc.h>
33 int vfs_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
39 if (dentry
->d_sb
->s_op
->statfs
) {
40 memset(buf
, 0, sizeof(*buf
));
41 retval
= security_sb_statfs(dentry
);
44 retval
= dentry
->d_sb
->s_op
->statfs(dentry
, buf
);
45 if (retval
== 0 && buf
->f_frsize
== 0)
46 buf
->f_frsize
= buf
->f_bsize
;
52 EXPORT_SYMBOL(vfs_statfs
);
54 static int vfs_statfs_native(struct dentry
*dentry
, struct statfs
*buf
)
59 retval
= vfs_statfs(dentry
, &st
);
63 if (sizeof(*buf
) == sizeof(st
))
64 memcpy(buf
, &st
, sizeof(st
));
66 if (sizeof buf
->f_blocks
== 4) {
67 if ((st
.f_blocks
| st
.f_bfree
| st
.f_bavail
|
68 st
.f_bsize
| st
.f_frsize
) &
69 0xffffffff00000000ULL
)
72 * f_files and f_ffree may be -1; it's okay to stuff
75 if (st
.f_files
!= -1 &&
76 (st
.f_files
& 0xffffffff00000000ULL
))
78 if (st
.f_ffree
!= -1 &&
79 (st
.f_ffree
& 0xffffffff00000000ULL
))
83 buf
->f_type
= st
.f_type
;
84 buf
->f_bsize
= st
.f_bsize
;
85 buf
->f_blocks
= st
.f_blocks
;
86 buf
->f_bfree
= st
.f_bfree
;
87 buf
->f_bavail
= st
.f_bavail
;
88 buf
->f_files
= st
.f_files
;
89 buf
->f_ffree
= st
.f_ffree
;
90 buf
->f_fsid
= st
.f_fsid
;
91 buf
->f_namelen
= st
.f_namelen
;
92 buf
->f_frsize
= st
.f_frsize
;
93 memset(buf
->f_spare
, 0, sizeof(buf
->f_spare
));
98 static int vfs_statfs64(struct dentry
*dentry
, struct statfs64
*buf
)
103 retval
= vfs_statfs(dentry
, &st
);
107 if (sizeof(*buf
) == sizeof(st
))
108 memcpy(buf
, &st
, sizeof(st
));
110 buf
->f_type
= st
.f_type
;
111 buf
->f_bsize
= st
.f_bsize
;
112 buf
->f_blocks
= st
.f_blocks
;
113 buf
->f_bfree
= st
.f_bfree
;
114 buf
->f_bavail
= st
.f_bavail
;
115 buf
->f_files
= st
.f_files
;
116 buf
->f_ffree
= st
.f_ffree
;
117 buf
->f_fsid
= st
.f_fsid
;
118 buf
->f_namelen
= st
.f_namelen
;
119 buf
->f_frsize
= st
.f_frsize
;
120 memset(buf
->f_spare
, 0, sizeof(buf
->f_spare
));
125 SYSCALL_DEFINE2(statfs
, const char __user
*, pathname
, struct statfs __user
*, buf
)
130 error
= user_path(pathname
, &path
);
133 error
= vfs_statfs_native(path
.dentry
, &tmp
);
134 if (!error
&& copy_to_user(buf
, &tmp
, sizeof(tmp
)))
141 SYSCALL_DEFINE3(statfs64
, const char __user
*, pathname
, size_t, sz
, struct statfs64 __user
*, buf
)
146 if (sz
!= sizeof(*buf
))
148 error
= user_path(pathname
, &path
);
151 error
= vfs_statfs64(path
.dentry
, &tmp
);
152 if (!error
&& copy_to_user(buf
, &tmp
, sizeof(tmp
)))
159 SYSCALL_DEFINE2(fstatfs
, unsigned int, fd
, struct statfs __user
*, buf
)
169 error
= vfs_statfs_native(file
->f_path
.dentry
, &tmp
);
170 if (!error
&& copy_to_user(buf
, &tmp
, sizeof(tmp
)))
177 SYSCALL_DEFINE3(fstatfs64
, unsigned int, fd
, size_t, sz
, struct statfs64 __user
*, buf
)
183 if (sz
!= sizeof(*buf
))
190 error
= vfs_statfs64(file
->f_path
.dentry
, &tmp
);
191 if (!error
&& copy_to_user(buf
, &tmp
, sizeof(tmp
)))
198 int do_truncate(struct dentry
*dentry
, loff_t length
, unsigned int time_attrs
,
202 struct iattr newattrs
;
204 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
208 newattrs
.ia_size
= length
;
209 newattrs
.ia_valid
= ATTR_SIZE
| time_attrs
;
211 newattrs
.ia_file
= filp
;
212 newattrs
.ia_valid
|= ATTR_FILE
;
215 /* Remove suid/sgid on truncate too */
216 newattrs
.ia_valid
|= should_remove_suid(dentry
);
218 mutex_lock(&dentry
->d_inode
->i_mutex
);
219 err
= notify_change(dentry
, &newattrs
);
220 mutex_unlock(&dentry
->d_inode
->i_mutex
);
224 static long do_sys_truncate(const char __user
*pathname
, loff_t length
)
231 if (length
< 0) /* sorry, but loff_t says... */
234 error
= user_path(pathname
, &path
);
237 inode
= path
.dentry
->d_inode
;
239 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
241 if (S_ISDIR(inode
->i_mode
))
245 if (!S_ISREG(inode
->i_mode
))
248 error
= mnt_want_write(path
.mnt
);
252 error
= inode_permission(inode
, MAY_WRITE
);
254 goto mnt_drop_write_and_out
;
257 if (IS_APPEND(inode
))
258 goto mnt_drop_write_and_out
;
260 error
= get_write_access(inode
);
262 goto mnt_drop_write_and_out
;
265 * Make sure that there are no leases. get_write_access() protects
266 * against the truncate racing with a lease-granting setlease().
268 error
= break_lease(inode
, FMODE_WRITE
);
270 goto put_write_and_out
;
272 error
= locks_verify_truncate(inode
, NULL
, length
);
274 error
= security_path_truncate(&path
, length
, 0);
277 error
= do_truncate(path
.dentry
, length
, 0, NULL
);
281 put_write_access(inode
);
282 mnt_drop_write_and_out
:
283 mnt_drop_write(path
.mnt
);
290 SYSCALL_DEFINE2(truncate
, const char __user
*, path
, unsigned long, length
)
292 /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
293 return do_sys_truncate(path
, (long)length
);
296 static long do_sys_ftruncate(unsigned int fd
, loff_t length
, int small
)
298 struct inode
* inode
;
299 struct dentry
*dentry
;
311 /* explicitly opened as large or we are on 64-bit box */
312 if (file
->f_flags
& O_LARGEFILE
)
315 dentry
= file
->f_path
.dentry
;
316 inode
= dentry
->d_inode
;
318 if (!S_ISREG(inode
->i_mode
) || !(file
->f_mode
& FMODE_WRITE
))
322 /* Cannot ftruncate over 2^31 bytes without large file support */
323 if (small
&& length
> MAX_NON_LFS
)
327 if (IS_APPEND(inode
))
330 error
= locks_verify_truncate(inode
, file
, length
);
332 error
= security_path_truncate(&file
->f_path
, length
,
333 ATTR_MTIME
|ATTR_CTIME
);
335 error
= do_truncate(dentry
, length
, ATTR_MTIME
|ATTR_CTIME
, file
);
342 SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, unsigned long, length
)
344 long ret
= do_sys_ftruncate(fd
, length
, 1);
345 /* avoid REGPARM breakage on x86: */
346 asmlinkage_protect(2, ret
, fd
, length
);
350 /* LFS versions of truncate are only needed on 32 bit machines */
351 #if BITS_PER_LONG == 32
352 SYSCALL_DEFINE(truncate64
)(const char __user
* path
, loff_t length
)
354 return do_sys_truncate(path
, length
);
356 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
357 asmlinkage
long SyS_truncate64(long path
, loff_t length
)
359 return SYSC_truncate64((const char __user
*) path
, length
);
361 SYSCALL_ALIAS(sys_truncate64
, SyS_truncate64
);
364 SYSCALL_DEFINE(ftruncate64
)(unsigned int fd
, loff_t length
)
366 long ret
= do_sys_ftruncate(fd
, length
, 0);
367 /* avoid REGPARM breakage on x86: */
368 asmlinkage_protect(2, ret
, fd
, length
);
371 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
372 asmlinkage
long SyS_ftruncate64(long fd
, loff_t length
)
374 return SYSC_ftruncate64((unsigned int) fd
, length
);
376 SYSCALL_ALIAS(sys_ftruncate64
, SyS_ftruncate64
);
378 #endif /* BITS_PER_LONG == 32 */
380 SYSCALL_DEFINE(fallocate
)(int fd
, int mode
, loff_t offset
, loff_t len
)
386 if (offset
< 0 || len
<= 0)
389 /* Return error if mode is not supported */
391 if (mode
&& !(mode
& FALLOC_FL_KEEP_SIZE
))
398 if (!(file
->f_mode
& FMODE_WRITE
))
401 * Revalidate the write permissions, in case security policy has
402 * changed since the files were opened.
404 ret
= security_file_permission(file
, MAY_WRITE
);
408 inode
= file
->f_path
.dentry
->d_inode
;
411 if (S_ISFIFO(inode
->i_mode
))
416 * Let individual file system decide if it supports preallocation
417 * for directories or not.
419 if (!S_ISREG(inode
->i_mode
) && !S_ISDIR(inode
->i_mode
))
423 /* Check for wrap through zero too */
424 if (((offset
+ len
) > inode
->i_sb
->s_maxbytes
) || ((offset
+ len
) < 0))
427 if (inode
->i_op
->fallocate
)
428 ret
= inode
->i_op
->fallocate(inode
, mode
, offset
, len
);
437 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
438 asmlinkage
long SyS_fallocate(long fd
, long mode
, loff_t offset
, loff_t len
)
440 return SYSC_fallocate((int)fd
, (int)mode
, offset
, len
);
442 SYSCALL_ALIAS(sys_fallocate
, SyS_fallocate
);
446 * access() needs to use the real uid/gid, not the effective uid/gid.
447 * We do this by temporarily clearing all FS-related capabilities and
448 * switching the fsuid/fsgid around to the real ones.
450 asmlinkage
long sys_faccessat(int dfd
, const char __user
*filename
, int mode
)
452 const struct cred
*old_cred
;
453 struct cred
*override_cred
;
458 if (mode
& ~S_IRWXO
) /* where's F_OK, X_OK, W_OK, R_OK? */
461 override_cred
= prepare_creds();
465 override_cred
->fsuid
= override_cred
->uid
;
466 override_cred
->fsgid
= override_cred
->gid
;
468 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
469 /* Clear the capabilities if we switch to a non-root user */
470 if (override_cred
->uid
)
471 cap_clear(override_cred
->cap_effective
);
473 override_cred
->cap_effective
=
474 override_cred
->cap_permitted
;
477 old_cred
= override_creds(override_cred
);
479 res
= user_path_at(dfd
, filename
, LOOKUP_FOLLOW
, &path
);
483 inode
= path
.dentry
->d_inode
;
485 if ((mode
& MAY_EXEC
) && S_ISREG(inode
->i_mode
)) {
487 * MAY_EXEC on regular files is denied if the fs is mounted
488 * with the "noexec" flag.
491 if (path
.mnt
->mnt_flags
& MNT_NOEXEC
)
492 goto out_path_release
;
495 res
= inode_permission(inode
, mode
| MAY_ACCESS
);
496 /* SuS v2 requires we report a read only fs too */
497 if (res
|| !(mode
& S_IWOTH
) || special_file(inode
->i_mode
))
498 goto out_path_release
;
500 * This is a rare case where using __mnt_is_readonly()
501 * is OK without a mnt_want/drop_write() pair. Since
502 * no actual write to the fs is performed here, we do
503 * not need to telegraph to that to anyone.
505 * By doing this, we accept that this access is
506 * inherently racy and know that the fs may change
507 * state before we even see this result.
509 if (__mnt_is_readonly(path
.mnt
))
515 revert_creds(old_cred
);
516 put_cred(override_cred
);
520 asmlinkage
long sys_access(const char __user
*filename
, int mode
)
522 return sys_faccessat(AT_FDCWD
, filename
, mode
);
525 asmlinkage
long sys_chdir(const char __user
* filename
)
530 error
= user_path_dir(filename
, &path
);
534 error
= inode_permission(path
.dentry
->d_inode
, MAY_EXEC
| MAY_ACCESS
);
538 set_fs_pwd(current
->fs
, &path
);
546 asmlinkage
long sys_fchdir(unsigned int fd
)
557 inode
= file
->f_path
.dentry
->d_inode
;
560 if (!S_ISDIR(inode
->i_mode
))
563 error
= inode_permission(inode
, MAY_EXEC
| MAY_ACCESS
);
565 set_fs_pwd(current
->fs
, &file
->f_path
);
572 asmlinkage
long sys_chroot(const char __user
* filename
)
577 error
= user_path_dir(filename
, &path
);
581 error
= inode_permission(path
.dentry
->d_inode
, MAY_EXEC
| MAY_ACCESS
);
586 if (!capable(CAP_SYS_CHROOT
))
589 set_fs_root(current
->fs
, &path
);
597 asmlinkage
long sys_fchmod(unsigned int fd
, mode_t mode
)
599 struct inode
* inode
;
600 struct dentry
* dentry
;
603 struct iattr newattrs
;
609 dentry
= file
->f_path
.dentry
;
610 inode
= dentry
->d_inode
;
612 audit_inode(NULL
, dentry
);
614 err
= mnt_want_write(file
->f_path
.mnt
);
617 mutex_lock(&inode
->i_mutex
);
618 if (mode
== (mode_t
) -1)
619 mode
= inode
->i_mode
;
620 newattrs
.ia_mode
= (mode
& S_IALLUGO
) | (inode
->i_mode
& ~S_IALLUGO
);
621 newattrs
.ia_valid
= ATTR_MODE
| ATTR_CTIME
;
622 err
= notify_change(dentry
, &newattrs
);
623 mutex_unlock(&inode
->i_mutex
);
624 mnt_drop_write(file
->f_path
.mnt
);
631 asmlinkage
long sys_fchmodat(int dfd
, const char __user
*filename
,
637 struct iattr newattrs
;
639 error
= user_path_at(dfd
, filename
, LOOKUP_FOLLOW
, &path
);
642 inode
= path
.dentry
->d_inode
;
644 error
= mnt_want_write(path
.mnt
);
647 mutex_lock(&inode
->i_mutex
);
648 if (mode
== (mode_t
) -1)
649 mode
= inode
->i_mode
;
650 newattrs
.ia_mode
= (mode
& S_IALLUGO
) | (inode
->i_mode
& ~S_IALLUGO
);
651 newattrs
.ia_valid
= ATTR_MODE
| ATTR_CTIME
;
652 error
= notify_change(path
.dentry
, &newattrs
);
653 mutex_unlock(&inode
->i_mutex
);
654 mnt_drop_write(path
.mnt
);
661 asmlinkage
long sys_chmod(const char __user
*filename
, mode_t mode
)
663 return sys_fchmodat(AT_FDCWD
, filename
, mode
);
666 static int chown_common(struct dentry
* dentry
, uid_t user
, gid_t group
)
668 struct inode
*inode
= dentry
->d_inode
;
670 struct iattr newattrs
;
672 newattrs
.ia_valid
= ATTR_CTIME
;
673 if (user
!= (uid_t
) -1) {
674 newattrs
.ia_valid
|= ATTR_UID
;
675 newattrs
.ia_uid
= user
;
677 if (group
!= (gid_t
) -1) {
678 newattrs
.ia_valid
|= ATTR_GID
;
679 newattrs
.ia_gid
= group
;
681 if (!S_ISDIR(inode
->i_mode
))
683 ATTR_KILL_SUID
| ATTR_KILL_SGID
| ATTR_KILL_PRIV
;
684 mutex_lock(&inode
->i_mutex
);
685 error
= notify_change(dentry
, &newattrs
);
686 mutex_unlock(&inode
->i_mutex
);
691 asmlinkage
long sys_chown(const char __user
* filename
, uid_t user
, gid_t group
)
696 error
= user_path(filename
, &path
);
699 error
= mnt_want_write(path
.mnt
);
702 error
= chown_common(path
.dentry
, user
, group
);
703 mnt_drop_write(path
.mnt
);
710 asmlinkage
long sys_fchownat(int dfd
, const char __user
*filename
, uid_t user
,
711 gid_t group
, int flag
)
717 if ((flag
& ~AT_SYMLINK_NOFOLLOW
) != 0)
720 follow
= (flag
& AT_SYMLINK_NOFOLLOW
) ? 0 : LOOKUP_FOLLOW
;
721 error
= user_path_at(dfd
, filename
, follow
, &path
);
724 error
= mnt_want_write(path
.mnt
);
727 error
= chown_common(path
.dentry
, user
, group
);
728 mnt_drop_write(path
.mnt
);
735 asmlinkage
long sys_lchown(const char __user
* filename
, uid_t user
, gid_t group
)
740 error
= user_lpath(filename
, &path
);
743 error
= mnt_want_write(path
.mnt
);
746 error
= chown_common(path
.dentry
, user
, group
);
747 mnt_drop_write(path
.mnt
);
755 asmlinkage
long sys_fchown(unsigned int fd
, uid_t user
, gid_t group
)
759 struct dentry
* dentry
;
765 error
= mnt_want_write(file
->f_path
.mnt
);
768 dentry
= file
->f_path
.dentry
;
769 audit_inode(NULL
, dentry
);
770 error
= chown_common(dentry
, user
, group
);
771 mnt_drop_write(file
->f_path
.mnt
);
779 * You have to be very careful that these write
780 * counts get cleaned up in error cases and
781 * upon __fput(). This should probably never
782 * be called outside of __dentry_open().
784 static inline int __get_file_write_access(struct inode
*inode
,
785 struct vfsmount
*mnt
)
788 error
= get_write_access(inode
);
792 * Do not take mount writer counts on
793 * special files since no writes to
794 * the mount itself will occur.
796 if (!special_file(inode
->i_mode
)) {
798 * Balanced in __fput()
800 error
= mnt_want_write(mnt
);
802 put_write_access(inode
);
807 static struct file
*__dentry_open(struct dentry
*dentry
, struct vfsmount
*mnt
,
808 int flags
, struct file
*f
,
809 int (*open
)(struct inode
*, struct file
*),
810 const struct cred
*cred
)
816 f
->f_mode
= (__force fmode_t
)((flags
+1) & O_ACCMODE
) | FMODE_LSEEK
|
817 FMODE_PREAD
| FMODE_PWRITE
;
818 inode
= dentry
->d_inode
;
819 if (f
->f_mode
& FMODE_WRITE
) {
820 error
= __get_file_write_access(inode
, mnt
);
823 if (!special_file(inode
->i_mode
))
827 f
->f_mapping
= inode
->i_mapping
;
828 f
->f_path
.dentry
= dentry
;
831 f
->f_op
= fops_get(inode
->i_fop
);
832 file_move(f
, &inode
->i_sb
->s_files
);
834 error
= security_dentry_open(f
, cred
);
838 if (!open
&& f
->f_op
)
839 open
= f
->f_op
->open
;
841 error
= open(inode
, f
);
846 f
->f_flags
&= ~(O_CREAT
| O_EXCL
| O_NOCTTY
| O_TRUNC
);
848 file_ra_state_init(&f
->f_ra
, f
->f_mapping
->host
->i_mapping
);
850 /* NB: we're sure to have correct a_ops only after f_op->open */
851 if (f
->f_flags
& O_DIRECT
) {
852 if (!f
->f_mapping
->a_ops
||
853 ((!f
->f_mapping
->a_ops
->direct_IO
) &&
854 (!f
->f_mapping
->a_ops
->get_xip_mem
))) {
856 f
= ERR_PTR(-EINVAL
);
864 if (f
->f_mode
& FMODE_WRITE
) {
865 put_write_access(inode
);
866 if (!special_file(inode
->i_mode
)) {
868 * We don't consider this a real
869 * mnt_want/drop_write() pair
870 * because it all happenend right
871 * here, so just reset the state.
878 f
->f_path
.dentry
= NULL
;
879 f
->f_path
.mnt
= NULL
;
884 return ERR_PTR(error
);
888 * lookup_instantiate_filp - instantiates the open intent filp
889 * @nd: pointer to nameidata
890 * @dentry: pointer to dentry
891 * @open: open callback
893 * Helper for filesystems that want to use lookup open intents and pass back
894 * a fully instantiated struct file to the caller.
895 * This function is meant to be called from within a filesystem's
897 * Beware of calling it for non-regular files! Those ->open methods might block
898 * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
899 * leading to a deadlock, as nobody can open that fifo anymore, because
900 * another process to open fifo will block on locked parent when doing lookup).
901 * Note that in case of error, nd->intent.open.file is destroyed, but the
902 * path information remains valid.
903 * If the open callback is set to NULL, then the standard f_op->open()
904 * filesystem callback is substituted.
906 struct file
*lookup_instantiate_filp(struct nameidata
*nd
, struct dentry
*dentry
,
907 int (*open
)(struct inode
*, struct file
*))
909 const struct cred
*cred
= current_cred();
911 if (IS_ERR(nd
->intent
.open
.file
))
915 nd
->intent
.open
.file
= __dentry_open(dget(dentry
), mntget(nd
->path
.mnt
),
916 nd
->intent
.open
.flags
- 1,
917 nd
->intent
.open
.file
,
920 return nd
->intent
.open
.file
;
922 release_open_intent(nd
);
923 nd
->intent
.open
.file
= (struct file
*)dentry
;
926 EXPORT_SYMBOL_GPL(lookup_instantiate_filp
);
929 * nameidata_to_filp - convert a nameidata to an open filp.
930 * @nd: pointer to nameidata
933 * Note that this function destroys the original nameidata
935 struct file
*nameidata_to_filp(struct nameidata
*nd
, int flags
)
937 const struct cred
*cred
= current_cred();
940 /* Pick up the filp from the open intent */
941 filp
= nd
->intent
.open
.file
;
942 /* Has the filesystem initialised the file for us? */
943 if (filp
->f_path
.dentry
== NULL
)
944 filp
= __dentry_open(nd
->path
.dentry
, nd
->path
.mnt
, flags
, filp
,
952 * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
955 struct file
*dentry_open(struct dentry
*dentry
, struct vfsmount
*mnt
, int flags
,
956 const struct cred
*cred
)
962 * We must always pass in a valid mount pointer. Historically
963 * callers got away with not passing it, but we must enforce this at
964 * the earliest possible point now to avoid strange problems deep in the
968 printk(KERN_WARNING
"%s called with NULL vfsmount\n", __func__
);
970 return ERR_PTR(-EINVAL
);
974 f
= get_empty_filp();
978 return ERR_PTR(error
);
981 return __dentry_open(dentry
, mnt
, flags
, f
, NULL
, cred
);
983 EXPORT_SYMBOL(dentry_open
);
985 static void __put_unused_fd(struct files_struct
*files
, unsigned int fd
)
987 struct fdtable
*fdt
= files_fdtable(files
);
988 __FD_CLR(fd
, fdt
->open_fds
);
989 if (fd
< files
->next_fd
)
993 void put_unused_fd(unsigned int fd
)
995 struct files_struct
*files
= current
->files
;
996 spin_lock(&files
->file_lock
);
997 __put_unused_fd(files
, fd
);
998 spin_unlock(&files
->file_lock
);
1001 EXPORT_SYMBOL(put_unused_fd
);
1004 * Install a file pointer in the fd array.
1006 * The VFS is full of places where we drop the files lock between
1007 * setting the open_fds bitmap and installing the file in the file
1008 * array. At any such point, we are vulnerable to a dup2() race
1009 * installing a file in the array before us. We need to detect this and
1010 * fput() the struct file we are about to overwrite in this case.
1012 * It should never happen - if we allow dup2() do it, _really_ bad things
1016 void fd_install(unsigned int fd
, struct file
*file
)
1018 struct files_struct
*files
= current
->files
;
1019 struct fdtable
*fdt
;
1020 spin_lock(&files
->file_lock
);
1021 fdt
= files_fdtable(files
);
1022 BUG_ON(fdt
->fd
[fd
] != NULL
);
1023 rcu_assign_pointer(fdt
->fd
[fd
], file
);
1024 spin_unlock(&files
->file_lock
);
1027 EXPORT_SYMBOL(fd_install
);
1029 long do_sys_open(int dfd
, const char __user
*filename
, int flags
, int mode
)
1031 char *tmp
= getname(filename
);
1032 int fd
= PTR_ERR(tmp
);
1035 fd
= get_unused_fd_flags(flags
);
1037 struct file
*f
= do_filp_open(dfd
, tmp
, flags
, mode
);
1042 fsnotify_open(f
->f_path
.dentry
);
1051 asmlinkage
long sys_open(const char __user
*filename
, int flags
, int mode
)
1055 if (force_o_largefile())
1056 flags
|= O_LARGEFILE
;
1058 ret
= do_sys_open(AT_FDCWD
, filename
, flags
, mode
);
1059 /* avoid REGPARM breakage on x86: */
1060 asmlinkage_protect(3, ret
, filename
, flags
, mode
);
1064 asmlinkage
long sys_openat(int dfd
, const char __user
*filename
, int flags
,
1069 if (force_o_largefile())
1070 flags
|= O_LARGEFILE
;
1072 ret
= do_sys_open(dfd
, filename
, flags
, mode
);
1073 /* avoid REGPARM breakage on x86: */
1074 asmlinkage_protect(4, ret
, dfd
, filename
, flags
, mode
);
1081 * For backward compatibility? Maybe this should be moved
1082 * into arch/i386 instead?
1084 asmlinkage
long sys_creat(const char __user
* pathname
, int mode
)
1086 return sys_open(pathname
, O_CREAT
| O_WRONLY
| O_TRUNC
, mode
);
1092 * "id" is the POSIX thread ID. We use the
1093 * files pointer for this..
1095 int filp_close(struct file
*filp
, fl_owner_t id
)
1099 if (!file_count(filp
)) {
1100 printk(KERN_ERR
"VFS: Close: file count is 0\n");
1104 if (filp
->f_op
&& filp
->f_op
->flush
)
1105 retval
= filp
->f_op
->flush(filp
, id
);
1107 dnotify_flush(filp
, id
);
1108 locks_remove_posix(filp
, id
);
1113 EXPORT_SYMBOL(filp_close
);
1116 * Careful here! We test whether the file pointer is NULL before
1117 * releasing the fd. This ensures that one clone task can't release
1118 * an fd while another clone is opening it.
1120 asmlinkage
long sys_close(unsigned int fd
)
1123 struct files_struct
*files
= current
->files
;
1124 struct fdtable
*fdt
;
1127 spin_lock(&files
->file_lock
);
1128 fdt
= files_fdtable(files
);
1129 if (fd
>= fdt
->max_fds
)
1134 rcu_assign_pointer(fdt
->fd
[fd
], NULL
);
1135 FD_CLR(fd
, fdt
->close_on_exec
);
1136 __put_unused_fd(files
, fd
);
1137 spin_unlock(&files
->file_lock
);
1138 retval
= filp_close(filp
, files
);
1140 /* can't restart close syscall because file table entry was cleared */
1141 if (unlikely(retval
== -ERESTARTSYS
||
1142 retval
== -ERESTARTNOINTR
||
1143 retval
== -ERESTARTNOHAND
||
1144 retval
== -ERESTART_RESTARTBLOCK
))
1150 spin_unlock(&files
->file_lock
);
1154 EXPORT_SYMBOL(sys_close
);
1157 * This routine simulates a hangup on the tty, to arrange that users
1158 * are given clean terminals at login time.
1160 asmlinkage
long sys_vhangup(void)
1162 if (capable(CAP_SYS_TTY_CONFIG
)) {
1170 * Called when an inode is about to be open.
1171 * We use this to disallow opening large files on 32bit systems if
1172 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1173 * on this flag in sys_open.
1175 int generic_file_open(struct inode
* inode
, struct file
* filp
)
1177 if (!(filp
->f_flags
& O_LARGEFILE
) && i_size_read(inode
) > MAX_NON_LFS
)
1182 EXPORT_SYMBOL(generic_file_open
);
1185 * This is used by subsystems that don't want seekable
1188 int nonseekable_open(struct inode
*inode
, struct file
*filp
)
1190 filp
->f_mode
&= ~(FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
);
1194 EXPORT_SYMBOL(nonseekable_open
);
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