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>
36 int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
40 struct iattr newattrs;
42 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
46 newattrs.ia_size = length;
47 newattrs.ia_valid = ATTR_SIZE | time_attrs;
49 newattrs.ia_file = filp;
50 newattrs.ia_valid |= ATTR_FILE;
53 /* Remove suid/sgid on truncate too */
54 ret = should_remove_suid(dentry);
56 newattrs.ia_valid |= ret | ATTR_FORCE;
58 mutex_lock(&dentry->d_inode->i_mutex);
59 ret = notify_change(dentry, &newattrs);
60 mutex_unlock(&dentry->d_inode->i_mutex);
64 static long do_sys_truncate(const char __user *pathname, loff_t length)
71 if (length < 0) /* sorry, but loff_t says... */
74 error = user_path(pathname, &path);
77 inode = path.dentry->d_inode;
79 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
81 if (S_ISDIR(inode->i_mode))
85 if (!S_ISREG(inode->i_mode))
88 error = mnt_want_write(path.mnt);
92 error = inode_permission(inode, MAY_WRITE);
94 goto mnt_drop_write_and_out;
98 goto mnt_drop_write_and_out;
100 error = get_write_access(inode);
102 goto mnt_drop_write_and_out;
105 * Make sure that there are no leases. get_write_access() protects
106 * against the truncate racing with a lease-granting setlease().
108 error = break_lease(inode, O_WRONLY);
110 goto put_write_and_out;
112 error = locks_verify_truncate(inode, NULL, length);
114 error = security_path_truncate(&path);
116 error = do_truncate(path.dentry, length, 0, NULL);
119 put_write_access(inode);
120 mnt_drop_write_and_out:
121 mnt_drop_write(path.mnt);
128 SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
130 return do_sys_truncate(path, length);
133 static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
135 struct inode * inode;
136 struct dentry *dentry;
148 /* explicitly opened as large or we are on 64-bit box */
149 if (file->f_flags & O_LARGEFILE)
152 dentry = file->f_path.dentry;
153 inode = dentry->d_inode;
155 if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
159 /* Cannot ftruncate over 2^31 bytes without large file support */
160 if (small && length > MAX_NON_LFS)
164 if (IS_APPEND(inode))
167 error = locks_verify_truncate(inode, file, length);
169 error = security_path_truncate(&file->f_path);
171 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file);
178 SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
180 long ret = do_sys_ftruncate(fd, length, 1);
181 /* avoid REGPARM breakage on x86: */
182 asmlinkage_protect(2, ret, fd, length);
186 /* LFS versions of truncate are only needed on 32 bit machines */
187 #if BITS_PER_LONG == 32
188 SYSCALL_DEFINE(truncate64)(const char __user * path, loff_t length)
190 return do_sys_truncate(path, length);
192 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
193 asmlinkage long SyS_truncate64(long path, loff_t length)
195 return SYSC_truncate64((const char __user *) path, length);
197 SYSCALL_ALIAS(sys_truncate64, SyS_truncate64);
200 SYSCALL_DEFINE(ftruncate64)(unsigned int fd, loff_t length)
202 long ret = do_sys_ftruncate(fd, length, 0);
203 /* avoid REGPARM breakage on x86: */
204 asmlinkage_protect(2, ret, fd, length);
207 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
208 asmlinkage long SyS_ftruncate64(long fd, loff_t length)
210 return SYSC_ftruncate64((unsigned int) fd, length);
212 SYSCALL_ALIAS(sys_ftruncate64, SyS_ftruncate64);
214 #endif /* BITS_PER_LONG == 32 */
217 int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
219 struct inode *inode = file->f_path.dentry->d_inode;
222 if (offset < 0 || len <= 0)
225 /* Return error if mode is not supported */
226 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
229 /* Punch hole must have keep size set */
230 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
231 !(mode & FALLOC_FL_KEEP_SIZE))
234 if (!(file->f_mode & FMODE_WRITE))
237 /* It's not possible punch hole on append only file */
238 if (mode & FALLOC_FL_PUNCH_HOLE && IS_APPEND(inode))
241 if (IS_IMMUTABLE(inode))
245 * Revalidate the write permissions, in case security policy has
246 * changed since the files were opened.
248 ret = security_file_permission(file, MAY_WRITE);
252 if (S_ISFIFO(inode->i_mode))
256 * Let individual file system decide if it supports preallocation
257 * for directories or not.
259 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
262 /* Check for wrap through zero too */
263 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
266 if (!file->f_op->fallocate)
269 return file->f_op->fallocate(file, mode, offset, len);
272 SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)
279 error = do_fallocate(file, mode, offset, len);
286 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
287 asmlinkage long SyS_fallocate(long fd, long mode, loff_t offset, loff_t len)
289 return SYSC_fallocate((int)fd, (int)mode, offset, len);
291 SYSCALL_ALIAS(sys_fallocate, SyS_fallocate);
295 * access() needs to use the real uid/gid, not the effective uid/gid.
296 * We do this by temporarily clearing all FS-related capabilities and
297 * switching the fsuid/fsgid around to the real ones.
299 SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
301 const struct cred *old_cred;
302 struct cred *override_cred;
307 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
310 override_cred = prepare_creds();
314 override_cred->fsuid = override_cred->uid;
315 override_cred->fsgid = override_cred->gid;
317 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
318 /* Clear the capabilities if we switch to a non-root user */
319 if (override_cred->uid)
320 cap_clear(override_cred->cap_effective);
322 override_cred->cap_effective =
323 override_cred->cap_permitted;
326 old_cred = override_creds(override_cred);
328 res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
332 inode = path.dentry->d_inode;
334 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
336 * MAY_EXEC on regular files is denied if the fs is mounted
337 * with the "noexec" flag.
340 if (path.mnt->mnt_flags & MNT_NOEXEC)
341 goto out_path_release;
344 res = inode_permission(inode, mode | MAY_ACCESS);
345 /* SuS v2 requires we report a read only fs too */
346 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
347 goto out_path_release;
349 * This is a rare case where using __mnt_is_readonly()
350 * is OK without a mnt_want/drop_write() pair. Since
351 * no actual write to the fs is performed here, we do
352 * not need to telegraph to that to anyone.
354 * By doing this, we accept that this access is
355 * inherently racy and know that the fs may change
356 * state before we even see this result.
358 if (__mnt_is_readonly(path.mnt))
364 revert_creds(old_cred);
365 put_cred(override_cred);
369 SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
371 return sys_faccessat(AT_FDCWD, filename, mode);
374 SYSCALL_DEFINE1(chdir, const char __user *, filename)
379 error = user_path_dir(filename, &path);
383 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
387 set_fs_pwd(current->fs, &path);
395 SYSCALL_DEFINE1(fchdir, unsigned int, fd)
406 inode = file->f_path.dentry->d_inode;
409 if (!S_ISDIR(inode->i_mode))
412 error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
414 set_fs_pwd(current->fs, &file->f_path);
421 SYSCALL_DEFINE1(chroot, const char __user *, filename)
426 error = user_path_dir(filename, &path);
430 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
435 if (!capable(CAP_SYS_CHROOT))
437 error = security_path_chroot(&path);
441 set_fs_root(current->fs, &path);
449 static int chmod_common(struct path *path, umode_t mode)
451 struct inode *inode = path->dentry->d_inode;
452 struct iattr newattrs;
455 error = mnt_want_write(path->mnt);
458 mutex_lock(&inode->i_mutex);
459 error = security_path_chmod(path, mode);
462 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
463 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
464 error = notify_change(path->dentry, &newattrs);
466 mutex_unlock(&inode->i_mutex);
467 mnt_drop_write(path->mnt);
471 SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
478 audit_inode(NULL, file->f_path.dentry);
479 err = chmod_common(&file->f_path, mode);
485 SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
490 error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
492 error = chmod_common(&path, mode);
498 SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
500 return sys_fchmodat(AT_FDCWD, filename, mode);
503 static int chown_common(struct path *path, uid_t user, gid_t group)
505 struct inode *inode = path->dentry->d_inode;
507 struct iattr newattrs;
509 newattrs.ia_valid = ATTR_CTIME;
510 if (user != (uid_t) -1) {
511 newattrs.ia_valid |= ATTR_UID;
512 newattrs.ia_uid = user;
514 if (group != (gid_t) -1) {
515 newattrs.ia_valid |= ATTR_GID;
516 newattrs.ia_gid = group;
518 if (!S_ISDIR(inode->i_mode))
520 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
521 mutex_lock(&inode->i_mutex);
522 error = security_path_chown(path, user, group);
524 error = notify_change(path->dentry, &newattrs);
525 mutex_unlock(&inode->i_mutex);
530 SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
535 error = user_path(filename, &path);
538 error = mnt_want_write(path.mnt);
541 error = chown_common(&path, user, group);
542 mnt_drop_write(path.mnt);
549 SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
550 gid_t, group, int, flag)
556 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
559 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
560 if (flag & AT_EMPTY_PATH)
561 lookup_flags |= LOOKUP_EMPTY;
562 error = user_path_at(dfd, filename, lookup_flags, &path);
565 error = mnt_want_write(path.mnt);
568 error = chown_common(&path, user, group);
569 mnt_drop_write(path.mnt);
576 SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
581 error = user_lpath(filename, &path);
584 error = mnt_want_write(path.mnt);
587 error = chown_common(&path, user, group);
588 mnt_drop_write(path.mnt);
595 SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
599 struct dentry * dentry;
605 error = mnt_want_write_file(file);
608 dentry = file->f_path.dentry;
609 audit_inode(NULL, dentry);
610 error = chown_common(&file->f_path, user, group);
611 mnt_drop_write_file(file);
619 * You have to be very careful that these write
620 * counts get cleaned up in error cases and
621 * upon __fput(). This should probably never
622 * be called outside of __dentry_open().
624 static inline int __get_file_write_access(struct inode *inode,
625 struct vfsmount *mnt)
628 error = get_write_access(inode);
632 * Do not take mount writer counts on
633 * special files since no writes to
634 * the mount itself will occur.
636 if (!special_file(inode->i_mode)) {
638 * Balanced in __fput()
640 error = mnt_want_write(mnt);
642 put_write_access(inode);
647 static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
649 int (*open)(struct inode *, struct file *),
650 const struct cred *cred)
652 static const struct file_operations empty_fops = {};
656 f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
657 FMODE_PREAD | FMODE_PWRITE;
659 if (unlikely(f->f_flags & O_PATH))
660 f->f_mode = FMODE_PATH;
662 inode = dentry->d_inode;
663 if (f->f_mode & FMODE_WRITE) {
664 error = __get_file_write_access(inode, mnt);
667 if (!special_file(inode->i_mode))
671 f->f_mapping = inode->i_mapping;
672 f->f_path.dentry = dentry;
675 file_sb_list_add(f, inode->i_sb);
677 if (unlikely(f->f_mode & FMODE_PATH)) {
678 f->f_op = &empty_fops;
682 f->f_op = fops_get(inode->i_fop);
684 error = security_dentry_open(f, cred);
688 error = break_lease(inode, f->f_flags);
692 if (!open && f->f_op)
693 open = f->f_op->open;
695 error = open(inode, f);
699 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
700 i_readcount_inc(inode);
702 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
704 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
706 /* NB: we're sure to have correct a_ops only after f_op->open */
707 if (f->f_flags & O_DIRECT) {
708 if (!f->f_mapping->a_ops ||
709 ((!f->f_mapping->a_ops->direct_IO) &&
710 (!f->f_mapping->a_ops->get_xip_mem))) {
712 f = ERR_PTR(-EINVAL);
720 if (f->f_mode & FMODE_WRITE) {
721 put_write_access(inode);
722 if (!special_file(inode->i_mode)) {
724 * We don't consider this a real
725 * mnt_want/drop_write() pair
726 * because it all happenend right
727 * here, so just reset the state.
734 f->f_path.dentry = NULL;
735 f->f_path.mnt = NULL;
740 return ERR_PTR(error);
744 * lookup_instantiate_filp - instantiates the open intent filp
745 * @nd: pointer to nameidata
746 * @dentry: pointer to dentry
747 * @open: open callback
749 * Helper for filesystems that want to use lookup open intents and pass back
750 * a fully instantiated struct file to the caller.
751 * This function is meant to be called from within a filesystem's
753 * Beware of calling it for non-regular files! Those ->open methods might block
754 * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
755 * leading to a deadlock, as nobody can open that fifo anymore, because
756 * another process to open fifo will block on locked parent when doing lookup).
757 * Note that in case of error, nd->intent.open.file is destroyed, but the
758 * path information remains valid.
759 * If the open callback is set to NULL, then the standard f_op->open()
760 * filesystem callback is substituted.
762 struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
763 int (*open)(struct inode *, struct file *))
765 const struct cred *cred = current_cred();
767 if (IS_ERR(nd->intent.open.file))
771 nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
772 nd->intent.open.file,
775 return nd->intent.open.file;
777 release_open_intent(nd);
778 nd->intent.open.file = ERR_CAST(dentry);
781 EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
784 * nameidata_to_filp - convert a nameidata to an open filp.
785 * @nd: pointer to nameidata
788 * Note that this function destroys the original nameidata
790 struct file *nameidata_to_filp(struct nameidata *nd)
792 const struct cred *cred = current_cred();
795 /* Pick up the filp from the open intent */
796 filp = nd->intent.open.file;
797 nd->intent.open.file = NULL;
799 /* Has the filesystem initialised the file for us? */
800 if (filp->f_path.dentry == NULL) {
802 filp = __dentry_open(nd->path.dentry, nd->path.mnt, filp,
809 * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
812 struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
813 const struct cred *cred)
818 validate_creds(cred);
820 /* We must always pass in a valid mount pointer. */
824 f = get_empty_filp();
828 return ERR_PTR(error);
832 return __dentry_open(dentry, mnt, f, NULL, cred);
834 EXPORT_SYMBOL(dentry_open);
836 static void __put_unused_fd(struct files_struct *files, unsigned int fd)
838 struct fdtable *fdt = files_fdtable(files);
839 __FD_CLR(fd, fdt->open_fds);
840 if (fd < files->next_fd)
844 void put_unused_fd(unsigned int fd)
846 struct files_struct *files = current->files;
847 spin_lock(&files->file_lock);
848 __put_unused_fd(files, fd);
849 spin_unlock(&files->file_lock);
852 EXPORT_SYMBOL(put_unused_fd);
855 * Install a file pointer in the fd array.
857 * The VFS is full of places where we drop the files lock between
858 * setting the open_fds bitmap and installing the file in the file
859 * array. At any such point, we are vulnerable to a dup2() race
860 * installing a file in the array before us. We need to detect this and
861 * fput() the struct file we are about to overwrite in this case.
863 * It should never happen - if we allow dup2() do it, _really_ bad things
867 void fd_install(unsigned int fd, struct file *file)
869 struct files_struct *files = current->files;
871 spin_lock(&files->file_lock);
872 fdt = files_fdtable(files);
873 BUG_ON(fdt->fd[fd] != NULL);
874 rcu_assign_pointer(fdt->fd[fd], file);
875 spin_unlock(&files->file_lock);
878 EXPORT_SYMBOL(fd_install);
880 static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
882 int lookup_flags = 0;
885 if (!(flags & O_CREAT))
889 /* Must never be set by userspace */
890 flags &= ~FMODE_NONOTIFY;
893 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
894 * check for O_DSYNC if the need any syncing at all we enforce it's
895 * always set instead of having to deal with possibly weird behaviour
896 * for malicious applications setting only __O_SYNC.
898 if (flags & __O_SYNC)
902 * If we have O_PATH in the open flag. Then we
903 * cannot have anything other than the below set of flags
905 if (flags & O_PATH) {
906 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
909 acc_mode = MAY_OPEN | ACC_MODE(flags);
912 op->open_flag = flags;
914 /* O_TRUNC implies we need access checks for write permissions */
916 acc_mode |= MAY_WRITE;
918 /* Allow the LSM permission hook to distinguish append
919 access from general write access. */
920 if (flags & O_APPEND)
921 acc_mode |= MAY_APPEND;
923 op->acc_mode = acc_mode;
925 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
927 if (flags & O_CREAT) {
928 op->intent |= LOOKUP_CREATE;
930 op->intent |= LOOKUP_EXCL;
933 if (flags & O_DIRECTORY)
934 lookup_flags |= LOOKUP_DIRECTORY;
935 if (!(flags & O_NOFOLLOW))
936 lookup_flags |= LOOKUP_FOLLOW;
941 * filp_open - open file and return file pointer
943 * @filename: path to open
944 * @flags: open flags as per the open(2) second argument
945 * @mode: mode for the new file if O_CREAT is set, else ignored
947 * This is the helper to open a file from kernelspace if you really
948 * have to. But in generally you should not do this, so please move
949 * along, nothing to see here..
951 struct file *filp_open(const char *filename, int flags, umode_t mode)
953 struct open_flags op;
954 int lookup = build_open_flags(flags, mode, &op);
955 return do_filp_open(AT_FDCWD, filename, &op, lookup);
957 EXPORT_SYMBOL(filp_open);
959 struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
960 const char *filename, int flags)
962 struct open_flags op;
963 int lookup = build_open_flags(flags, 0, &op);
965 return ERR_PTR(-EINVAL);
966 if (!filename && (flags & O_DIRECTORY))
967 if (!dentry->d_inode->i_op->lookup)
968 return ERR_PTR(-ENOTDIR);
969 return do_file_open_root(dentry, mnt, filename, &op, lookup);
971 EXPORT_SYMBOL(file_open_root);
973 long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
975 struct open_flags op;
976 int lookup = build_open_flags(flags, mode, &op);
977 char *tmp = getname(filename);
978 int fd = PTR_ERR(tmp);
981 fd = get_unused_fd_flags(flags);
983 struct file *f = do_filp_open(dfd, tmp, &op, lookup);
997 SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
1001 if (force_o_largefile())
1002 flags |= O_LARGEFILE;
1004 ret = do_sys_open(AT_FDCWD, filename, flags, mode);
1005 /* avoid REGPARM breakage on x86: */
1006 asmlinkage_protect(3, ret, filename, flags, mode);
1010 SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
1015 if (force_o_largefile())
1016 flags |= O_LARGEFILE;
1018 ret = do_sys_open(dfd, filename, flags, mode);
1019 /* avoid REGPARM breakage on x86: */
1020 asmlinkage_protect(4, ret, dfd, filename, flags, mode);
1027 * For backward compatibility? Maybe this should be moved
1028 * into arch/i386 instead?
1030 SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
1032 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1038 * "id" is the POSIX thread ID. We use the
1039 * files pointer for this..
1041 int filp_close(struct file *filp, fl_owner_t id)
1045 if (!file_count(filp)) {
1046 printk(KERN_ERR "VFS: Close: file count is 0\n");
1050 if (filp->f_op && filp->f_op->flush)
1051 retval = filp->f_op->flush(filp, id);
1053 if (likely(!(filp->f_mode & FMODE_PATH))) {
1054 dnotify_flush(filp, id);
1055 locks_remove_posix(filp, id);
1061 EXPORT_SYMBOL(filp_close);
1064 * Careful here! We test whether the file pointer is NULL before
1065 * releasing the fd. This ensures that one clone task can't release
1066 * an fd while another clone is opening it.
1068 SYSCALL_DEFINE1(close, unsigned int, fd)
1071 struct files_struct *files = current->files;
1072 struct fdtable *fdt;
1075 spin_lock(&files->file_lock);
1076 fdt = files_fdtable(files);
1077 if (fd >= fdt->max_fds)
1082 rcu_assign_pointer(fdt->fd[fd], NULL);
1083 FD_CLR(fd, fdt->close_on_exec);
1084 __put_unused_fd(files, fd);
1085 spin_unlock(&files->file_lock);
1086 retval = filp_close(filp, files);
1088 /* can't restart close syscall because file table entry was cleared */
1089 if (unlikely(retval == -ERESTARTSYS ||
1090 retval == -ERESTARTNOINTR ||
1091 retval == -ERESTARTNOHAND ||
1092 retval == -ERESTART_RESTARTBLOCK))
1098 spin_unlock(&files->file_lock);
1101 EXPORT_SYMBOL(sys_close);
1104 * This routine simulates a hangup on the tty, to arrange that users
1105 * are given clean terminals at login time.
1107 SYSCALL_DEFINE0(vhangup)
1109 if (capable(CAP_SYS_TTY_CONFIG)) {
1117 * Called when an inode is about to be open.
1118 * We use this to disallow opening large files on 32bit systems if
1119 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1120 * on this flag in sys_open.
1122 int generic_file_open(struct inode * inode, struct file * filp)
1124 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1129 EXPORT_SYMBOL(generic_file_open);
1132 * This is used by subsystems that don't want seekable
1133 * file descriptors. The function is not supposed to ever fail, the only
1134 * reason it returns an 'int' and not 'void' is so that it can be plugged
1135 * directly into file_operations structure.
1137 int nonseekable_open(struct inode *inode, struct file *filp)
1139 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1143 EXPORT_SYMBOL(nonseekable_open);