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 asmlinkage long sys_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)))
142 asmlinkage long sys_statfs64(const char __user *pathname, size_t sz, struct statfs64 __user *buf)
147 if (sz != sizeof(*buf))
149 error = user_path(pathname, &path);
152 error = vfs_statfs64(path.dentry, &tmp);
153 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
161 asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf)
171 error = vfs_statfs_native(file->f_path.dentry, &tmp);
172 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
179 asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf)
185 if (sz != sizeof(*buf))
192 error = vfs_statfs64(file->f_path.dentry, &tmp);
193 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
200 int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
204 struct iattr newattrs;
206 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
210 newattrs.ia_size = length;
211 newattrs.ia_valid = ATTR_SIZE | time_attrs;
213 newattrs.ia_file = filp;
214 newattrs.ia_valid |= ATTR_FILE;
217 /* Remove suid/sgid on truncate too */
218 newattrs.ia_valid |= should_remove_suid(dentry);
220 mutex_lock(&dentry->d_inode->i_mutex);
221 err = notify_change(dentry, &newattrs);
222 mutex_unlock(&dentry->d_inode->i_mutex);
226 static long do_sys_truncate(const char __user *pathname, loff_t length)
233 if (length < 0) /* sorry, but loff_t says... */
236 error = user_path(pathname, &path);
239 inode = path.dentry->d_inode;
241 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
243 if (S_ISDIR(inode->i_mode))
247 if (!S_ISREG(inode->i_mode))
250 error = mnt_want_write(path.mnt);
254 error = inode_permission(inode, MAY_WRITE);
256 goto mnt_drop_write_and_out;
259 if (IS_APPEND(inode))
260 goto mnt_drop_write_and_out;
262 error = get_write_access(inode);
264 goto mnt_drop_write_and_out;
267 * Make sure that there are no leases. get_write_access() protects
268 * against the truncate racing with a lease-granting setlease().
270 error = break_lease(inode, FMODE_WRITE);
272 goto put_write_and_out;
274 error = locks_verify_truncate(inode, NULL, length);
276 error = security_path_truncate(&path, length, 0);
279 error = do_truncate(path.dentry, length, 0, NULL);
283 put_write_access(inode);
284 mnt_drop_write_and_out:
285 mnt_drop_write(path.mnt);
292 asmlinkage long sys_truncate(const char __user * path, unsigned long length)
294 /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
295 return do_sys_truncate(path, (long)length);
298 static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
300 struct inode * inode;
301 struct dentry *dentry;
313 /* explicitly opened as large or we are on 64-bit box */
314 if (file->f_flags & O_LARGEFILE)
317 dentry = file->f_path.dentry;
318 inode = dentry->d_inode;
320 if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
324 /* Cannot ftruncate over 2^31 bytes without large file support */
325 if (small && length > MAX_NON_LFS)
329 if (IS_APPEND(inode))
332 error = locks_verify_truncate(inode, file, length);
334 error = security_path_truncate(&file->f_path, length,
335 ATTR_MTIME|ATTR_CTIME);
337 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file);
344 asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
346 long ret = do_sys_ftruncate(fd, length, 1);
347 /* avoid REGPARM breakage on x86: */
348 asmlinkage_protect(2, ret, fd, length);
352 /* LFS versions of truncate are only needed on 32 bit machines */
353 #if BITS_PER_LONG == 32
354 SYSCALL_DEFINE(truncate64)(const char __user * path, loff_t length)
356 return do_sys_truncate(path, length);
358 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
359 asmlinkage long SyS_truncate64(long path, loff_t length)
361 return SYSC_truncate64((const char __user *) path, length);
363 SYSCALL_ALIAS(sys_truncate64, SyS_truncate64);
366 SYSCALL_DEFINE(ftruncate64)(unsigned int fd, loff_t length)
368 long ret = do_sys_ftruncate(fd, length, 0);
369 /* avoid REGPARM breakage on x86: */
370 asmlinkage_protect(2, ret, fd, length);
373 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
374 asmlinkage long SyS_ftruncate64(long fd, loff_t length)
376 return SYSC_ftruncate64((unsigned int) fd, length);
378 SYSCALL_ALIAS(sys_ftruncate64, SyS_ftruncate64);
380 #endif /* BITS_PER_LONG == 32 */
382 SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)
388 if (offset < 0 || len <= 0)
391 /* Return error if mode is not supported */
393 if (mode && !(mode & FALLOC_FL_KEEP_SIZE))
400 if (!(file->f_mode & FMODE_WRITE))
403 * Revalidate the write permissions, in case security policy has
404 * changed since the files were opened.
406 ret = security_file_permission(file, MAY_WRITE);
410 inode = file->f_path.dentry->d_inode;
413 if (S_ISFIFO(inode->i_mode))
418 * Let individual file system decide if it supports preallocation
419 * for directories or not.
421 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
425 /* Check for wrap through zero too */
426 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
429 if (inode->i_op->fallocate)
430 ret = inode->i_op->fallocate(inode, mode, offset, len);
439 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
440 asmlinkage long SyS_fallocate(long fd, long mode, loff_t offset, loff_t len)
442 return SYSC_fallocate((int)fd, (int)mode, offset, len);
444 SYSCALL_ALIAS(sys_fallocate, SyS_fallocate);
448 * access() needs to use the real uid/gid, not the effective uid/gid.
449 * We do this by temporarily clearing all FS-related capabilities and
450 * switching the fsuid/fsgid around to the real ones.
452 asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
454 const struct cred *old_cred;
455 struct cred *override_cred;
460 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
463 override_cred = prepare_creds();
467 override_cred->fsuid = override_cred->uid;
468 override_cred->fsgid = override_cred->gid;
470 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
471 /* Clear the capabilities if we switch to a non-root user */
472 if (override_cred->uid)
473 cap_clear(override_cred->cap_effective);
475 override_cred->cap_effective =
476 override_cred->cap_permitted;
479 old_cred = override_creds(override_cred);
481 res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
485 inode = path.dentry->d_inode;
487 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
489 * MAY_EXEC on regular files is denied if the fs is mounted
490 * with the "noexec" flag.
493 if (path.mnt->mnt_flags & MNT_NOEXEC)
494 goto out_path_release;
497 res = inode_permission(inode, mode | MAY_ACCESS);
498 /* SuS v2 requires we report a read only fs too */
499 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
500 goto out_path_release;
502 * This is a rare case where using __mnt_is_readonly()
503 * is OK without a mnt_want/drop_write() pair. Since
504 * no actual write to the fs is performed here, we do
505 * not need to telegraph to that to anyone.
507 * By doing this, we accept that this access is
508 * inherently racy and know that the fs may change
509 * state before we even see this result.
511 if (__mnt_is_readonly(path.mnt))
517 revert_creds(old_cred);
518 put_cred(override_cred);
522 asmlinkage long sys_access(const char __user *filename, int mode)
524 return sys_faccessat(AT_FDCWD, filename, mode);
527 asmlinkage long sys_chdir(const char __user * filename)
532 error = user_path_dir(filename, &path);
536 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
540 set_fs_pwd(current->fs, &path);
548 asmlinkage long sys_fchdir(unsigned int fd)
559 inode = file->f_path.dentry->d_inode;
562 if (!S_ISDIR(inode->i_mode))
565 error = inode_permission(inode, MAY_EXEC | MAY_ACCESS);
567 set_fs_pwd(current->fs, &file->f_path);
574 asmlinkage long sys_chroot(const char __user * filename)
579 error = user_path_dir(filename, &path);
583 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
588 if (!capable(CAP_SYS_CHROOT))
591 set_fs_root(current->fs, &path);
599 asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
601 struct inode * inode;
602 struct dentry * dentry;
605 struct iattr newattrs;
611 dentry = file->f_path.dentry;
612 inode = dentry->d_inode;
614 audit_inode(NULL, dentry);
616 err = mnt_want_write(file->f_path.mnt);
619 mutex_lock(&inode->i_mutex);
620 if (mode == (mode_t) -1)
621 mode = inode->i_mode;
622 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
623 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
624 err = notify_change(dentry, &newattrs);
625 mutex_unlock(&inode->i_mutex);
626 mnt_drop_write(file->f_path.mnt);
633 asmlinkage long sys_fchmodat(int dfd, const char __user *filename,
639 struct iattr newattrs;
641 error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
644 inode = path.dentry->d_inode;
646 error = mnt_want_write(path.mnt);
649 mutex_lock(&inode->i_mutex);
650 if (mode == (mode_t) -1)
651 mode = inode->i_mode;
652 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
653 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
654 error = notify_change(path.dentry, &newattrs);
655 mutex_unlock(&inode->i_mutex);
656 mnt_drop_write(path.mnt);
663 asmlinkage long sys_chmod(const char __user *filename, mode_t mode)
665 return sys_fchmodat(AT_FDCWD, filename, mode);
668 static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
670 struct inode *inode = dentry->d_inode;
672 struct iattr newattrs;
674 newattrs.ia_valid = ATTR_CTIME;
675 if (user != (uid_t) -1) {
676 newattrs.ia_valid |= ATTR_UID;
677 newattrs.ia_uid = user;
679 if (group != (gid_t) -1) {
680 newattrs.ia_valid |= ATTR_GID;
681 newattrs.ia_gid = group;
683 if (!S_ISDIR(inode->i_mode))
685 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
686 mutex_lock(&inode->i_mutex);
687 error = notify_change(dentry, &newattrs);
688 mutex_unlock(&inode->i_mutex);
693 asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
698 error = user_path(filename, &path);
701 error = mnt_want_write(path.mnt);
704 error = chown_common(path.dentry, user, group);
705 mnt_drop_write(path.mnt);
712 asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
713 gid_t group, int flag)
719 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
722 follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
723 error = user_path_at(dfd, filename, follow, &path);
726 error = mnt_want_write(path.mnt);
729 error = chown_common(path.dentry, user, group);
730 mnt_drop_write(path.mnt);
737 asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group)
742 error = user_lpath(filename, &path);
745 error = mnt_want_write(path.mnt);
748 error = chown_common(path.dentry, user, group);
749 mnt_drop_write(path.mnt);
757 asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
761 struct dentry * dentry;
767 error = mnt_want_write(file->f_path.mnt);
770 dentry = file->f_path.dentry;
771 audit_inode(NULL, dentry);
772 error = chown_common(dentry, user, group);
773 mnt_drop_write(file->f_path.mnt);
781 * You have to be very careful that these write
782 * counts get cleaned up in error cases and
783 * upon __fput(). This should probably never
784 * be called outside of __dentry_open().
786 static inline int __get_file_write_access(struct inode *inode,
787 struct vfsmount *mnt)
790 error = get_write_access(inode);
794 * Do not take mount writer counts on
795 * special files since no writes to
796 * the mount itself will occur.
798 if (!special_file(inode->i_mode)) {
800 * Balanced in __fput()
802 error = mnt_want_write(mnt);
804 put_write_access(inode);
809 static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
810 int flags, struct file *f,
811 int (*open)(struct inode *, struct file *),
812 const struct cred *cred)
818 f->f_mode = (__force fmode_t)((flags+1) & O_ACCMODE) | FMODE_LSEEK |
819 FMODE_PREAD | FMODE_PWRITE;
820 inode = dentry->d_inode;
821 if (f->f_mode & FMODE_WRITE) {
822 error = __get_file_write_access(inode, mnt);
825 if (!special_file(inode->i_mode))
829 f->f_mapping = inode->i_mapping;
830 f->f_path.dentry = dentry;
833 f->f_op = fops_get(inode->i_fop);
834 file_move(f, &inode->i_sb->s_files);
836 error = security_dentry_open(f, cred);
840 if (!open && f->f_op)
841 open = f->f_op->open;
843 error = open(inode, f);
848 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
850 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
852 /* NB: we're sure to have correct a_ops only after f_op->open */
853 if (f->f_flags & O_DIRECT) {
854 if (!f->f_mapping->a_ops ||
855 ((!f->f_mapping->a_ops->direct_IO) &&
856 (!f->f_mapping->a_ops->get_xip_mem))) {
858 f = ERR_PTR(-EINVAL);
866 if (f->f_mode & FMODE_WRITE) {
867 put_write_access(inode);
868 if (!special_file(inode->i_mode)) {
870 * We don't consider this a real
871 * mnt_want/drop_write() pair
872 * because it all happenend right
873 * here, so just reset the state.
880 f->f_path.dentry = NULL;
881 f->f_path.mnt = NULL;
886 return ERR_PTR(error);
890 * lookup_instantiate_filp - instantiates the open intent filp
891 * @nd: pointer to nameidata
892 * @dentry: pointer to dentry
893 * @open: open callback
895 * Helper for filesystems that want to use lookup open intents and pass back
896 * a fully instantiated struct file to the caller.
897 * This function is meant to be called from within a filesystem's
899 * Beware of calling it for non-regular files! Those ->open methods might block
900 * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
901 * leading to a deadlock, as nobody can open that fifo anymore, because
902 * another process to open fifo will block on locked parent when doing lookup).
903 * Note that in case of error, nd->intent.open.file is destroyed, but the
904 * path information remains valid.
905 * If the open callback is set to NULL, then the standard f_op->open()
906 * filesystem callback is substituted.
908 struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
909 int (*open)(struct inode *, struct file *))
911 const struct cred *cred = current_cred();
913 if (IS_ERR(nd->intent.open.file))
917 nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
918 nd->intent.open.flags - 1,
919 nd->intent.open.file,
922 return nd->intent.open.file;
924 release_open_intent(nd);
925 nd->intent.open.file = (struct file *)dentry;
928 EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
931 * nameidata_to_filp - convert a nameidata to an open filp.
932 * @nd: pointer to nameidata
935 * Note that this function destroys the original nameidata
937 struct file *nameidata_to_filp(struct nameidata *nd, int flags)
939 const struct cred *cred = current_cred();
942 /* Pick up the filp from the open intent */
943 filp = nd->intent.open.file;
944 /* Has the filesystem initialised the file for us? */
945 if (filp->f_path.dentry == NULL)
946 filp = __dentry_open(nd->path.dentry, nd->path.mnt, flags, filp,
954 * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
957 struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
958 const struct cred *cred)
964 * We must always pass in a valid mount pointer. Historically
965 * callers got away with not passing it, but we must enforce this at
966 * the earliest possible point now to avoid strange problems deep in the
970 printk(KERN_WARNING "%s called with NULL vfsmount\n", __func__);
972 return ERR_PTR(-EINVAL);
976 f = get_empty_filp();
980 return ERR_PTR(error);
983 return __dentry_open(dentry, mnt, flags, f, NULL, cred);
985 EXPORT_SYMBOL(dentry_open);
987 static void __put_unused_fd(struct files_struct *files, unsigned int fd)
989 struct fdtable *fdt = files_fdtable(files);
990 __FD_CLR(fd, fdt->open_fds);
991 if (fd < files->next_fd)
995 void put_unused_fd(unsigned int fd)
997 struct files_struct *files = current->files;
998 spin_lock(&files->file_lock);
999 __put_unused_fd(files, fd);
1000 spin_unlock(&files->file_lock);
1003 EXPORT_SYMBOL(put_unused_fd);
1006 * Install a file pointer in the fd array.
1008 * The VFS is full of places where we drop the files lock between
1009 * setting the open_fds bitmap and installing the file in the file
1010 * array. At any such point, we are vulnerable to a dup2() race
1011 * installing a file in the array before us. We need to detect this and
1012 * fput() the struct file we are about to overwrite in this case.
1014 * It should never happen - if we allow dup2() do it, _really_ bad things
1018 void fd_install(unsigned int fd, struct file *file)
1020 struct files_struct *files = current->files;
1021 struct fdtable *fdt;
1022 spin_lock(&files->file_lock);
1023 fdt = files_fdtable(files);
1024 BUG_ON(fdt->fd[fd] != NULL);
1025 rcu_assign_pointer(fdt->fd[fd], file);
1026 spin_unlock(&files->file_lock);
1029 EXPORT_SYMBOL(fd_install);
1031 long do_sys_open(int dfd, const char __user *filename, int flags, int mode)
1033 char *tmp = getname(filename);
1034 int fd = PTR_ERR(tmp);
1037 fd = get_unused_fd_flags(flags);
1039 struct file *f = do_filp_open(dfd, tmp, flags, mode);
1044 fsnotify_open(f->f_path.dentry);
1053 asmlinkage long sys_open(const char __user *filename, int flags, int mode)
1057 if (force_o_largefile())
1058 flags |= O_LARGEFILE;
1060 ret = do_sys_open(AT_FDCWD, filename, flags, mode);
1061 /* avoid REGPARM breakage on x86: */
1062 asmlinkage_protect(3, ret, filename, flags, mode);
1066 asmlinkage long sys_openat(int dfd, const char __user *filename, int flags,
1071 if (force_o_largefile())
1072 flags |= O_LARGEFILE;
1074 ret = do_sys_open(dfd, filename, flags, mode);
1075 /* avoid REGPARM breakage on x86: */
1076 asmlinkage_protect(4, ret, dfd, filename, flags, mode);
1083 * For backward compatibility? Maybe this should be moved
1084 * into arch/i386 instead?
1086 asmlinkage long sys_creat(const char __user * pathname, int mode)
1088 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1094 * "id" is the POSIX thread ID. We use the
1095 * files pointer for this..
1097 int filp_close(struct file *filp, fl_owner_t id)
1101 if (!file_count(filp)) {
1102 printk(KERN_ERR "VFS: Close: file count is 0\n");
1106 if (filp->f_op && filp->f_op->flush)
1107 retval = filp->f_op->flush(filp, id);
1109 dnotify_flush(filp, id);
1110 locks_remove_posix(filp, id);
1115 EXPORT_SYMBOL(filp_close);
1118 * Careful here! We test whether the file pointer is NULL before
1119 * releasing the fd. This ensures that one clone task can't release
1120 * an fd while another clone is opening it.
1122 asmlinkage long sys_close(unsigned int fd)
1125 struct files_struct *files = current->files;
1126 struct fdtable *fdt;
1129 spin_lock(&files->file_lock);
1130 fdt = files_fdtable(files);
1131 if (fd >= fdt->max_fds)
1136 rcu_assign_pointer(fdt->fd[fd], NULL);
1137 FD_CLR(fd, fdt->close_on_exec);
1138 __put_unused_fd(files, fd);
1139 spin_unlock(&files->file_lock);
1140 retval = filp_close(filp, files);
1142 /* can't restart close syscall because file table entry was cleared */
1143 if (unlikely(retval == -ERESTARTSYS ||
1144 retval == -ERESTARTNOINTR ||
1145 retval == -ERESTARTNOHAND ||
1146 retval == -ERESTART_RESTARTBLOCK))
1152 spin_unlock(&files->file_lock);
1156 EXPORT_SYMBOL(sys_close);
1159 * This routine simulates a hangup on the tty, to arrange that users
1160 * are given clean terminals at login time.
1162 asmlinkage long sys_vhangup(void)
1164 if (capable(CAP_SYS_TTY_CONFIG)) {
1172 * Called when an inode is about to be open.
1173 * We use this to disallow opening large files on 32bit systems if
1174 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1175 * on this flag in sys_open.
1177 int generic_file_open(struct inode * inode, struct file * filp)
1179 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1184 EXPORT_SYMBOL(generic_file_open);
1187 * This is used by subsystems that don't want seekable
1190 int nonseekable_open(struct inode *inode, struct file *filp)
1192 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1196 EXPORT_SYMBOL(nonseekable_open);