4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/string.h>
9 #include <linux/file.h>
10 #include <linux/fdtable.h>
11 #include <linux/fsnotify.h>
12 #include <linux/module.h>
13 #include <linux/tty.h>
14 #include <linux/namei.h>
15 #include <linux/backing-dev.h>
16 #include <linux/capability.h>
17 #include <linux/securebits.h>
18 #include <linux/security.h>
19 #include <linux/mount.h>
20 #include <linux/fcntl.h>
21 #include <linux/slab.h>
22 #include <asm/uaccess.h>
24 #include <linux/personality.h>
25 #include <linux/pagemap.h>
26 #include <linux/syscalls.h>
27 #include <linux/rcupdate.h>
28 #include <linux/audit.h>
29 #include <linux/falloc.h>
30 #include <linux/fs_struct.h>
31 #include <linux/ima.h>
32 #include <linux/dnotify.h>
33 #include <linux/compat.h>
37 int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
41 struct iattr newattrs;
43 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
47 newattrs.ia_size = length;
48 newattrs.ia_valid = ATTR_SIZE | time_attrs;
50 newattrs.ia_file = filp;
51 newattrs.ia_valid |= ATTR_FILE;
54 /* Remove suid/sgid on truncate too */
55 ret = should_remove_suid(dentry);
57 newattrs.ia_valid |= ret | ATTR_FORCE;
59 mutex_lock(&dentry->d_inode->i_mutex);
60 /* Note any delegations or leases have already been broken: */
61 ret = notify_change(dentry, &newattrs, NULL);
62 mutex_unlock(&dentry->d_inode->i_mutex);
66 long vfs_truncate(struct path *path, loff_t length)
71 inode = path->dentry->d_inode;
73 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
74 if (S_ISDIR(inode->i_mode))
76 if (!S_ISREG(inode->i_mode))
79 error = mnt_want_write(path->mnt);
83 error = inode_permission(inode, MAY_WRITE);
85 goto mnt_drop_write_and_out;
89 goto mnt_drop_write_and_out;
91 error = get_write_access(inode);
93 goto mnt_drop_write_and_out;
96 * Make sure that there are no leases. get_write_access() protects
97 * against the truncate racing with a lease-granting setlease().
99 error = break_lease(inode, O_WRONLY);
101 goto put_write_and_out;
103 error = locks_verify_truncate(inode, NULL, length);
105 error = security_path_truncate(path);
107 error = do_truncate(path->dentry, length, 0, NULL);
110 put_write_access(inode);
111 mnt_drop_write_and_out:
112 mnt_drop_write(path->mnt);
116 EXPORT_SYMBOL_GPL(vfs_truncate);
118 static long do_sys_truncate(const char __user *pathname, loff_t length)
120 unsigned int lookup_flags = LOOKUP_FOLLOW;
124 if (length < 0) /* sorry, but loff_t says... */
128 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
130 error = vfs_truncate(&path, length);
133 if (retry_estale(error, lookup_flags)) {
134 lookup_flags |= LOOKUP_REVAL;
140 SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
142 return do_sys_truncate(path, length);
146 COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
148 return do_sys_truncate(path, length);
152 static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
155 struct dentry *dentry;
167 /* explicitly opened as large or we are on 64-bit box */
168 if (f.file->f_flags & O_LARGEFILE)
171 dentry = f.file->f_path.dentry;
172 inode = dentry->d_inode;
174 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
178 /* Cannot ftruncate over 2^31 bytes without large file support */
179 if (small && length > MAX_NON_LFS)
183 if (IS_APPEND(inode))
186 sb_start_write(inode->i_sb);
187 error = locks_verify_truncate(inode, f.file, length);
189 error = security_path_truncate(&f.file->f_path);
191 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
192 sb_end_write(inode->i_sb);
199 SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
201 return do_sys_ftruncate(fd, length, 1);
205 COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
207 return do_sys_ftruncate(fd, length, 1);
211 /* LFS versions of truncate are only needed on 32 bit machines */
212 #if BITS_PER_LONG == 32
213 SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
215 return do_sys_truncate(path, length);
218 SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
220 return do_sys_ftruncate(fd, length, 0);
222 #endif /* BITS_PER_LONG == 32 */
225 int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
227 struct inode *inode = file_inode(file);
230 if (offset < 0 || len <= 0)
233 /* Return error if mode is not supported */
234 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
235 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
238 /* Punch hole and zero range are mutually exclusive */
239 if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
240 (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
243 /* Punch hole must have keep size set */
244 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
245 !(mode & FALLOC_FL_KEEP_SIZE))
248 /* Collapse range should only be used exclusively. */
249 if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
250 (mode & ~FALLOC_FL_COLLAPSE_RANGE))
253 if (!(file->f_mode & FMODE_WRITE))
257 * We can only allow pure fallocate on append only files
259 if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
262 if (IS_IMMUTABLE(inode))
266 * Revalidate the write permissions, in case security policy has
267 * changed since the files were opened.
269 ret = security_file_permission(file, MAY_WRITE);
273 if (S_ISFIFO(inode->i_mode))
277 * Let individual file system decide if it supports preallocation
278 * for directories or not.
280 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
283 /* Check for wrap through zero too */
284 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
287 if (!file->f_op->fallocate)
290 sb_start_write(inode->i_sb);
291 ret = file->f_op->fallocate(file, mode, offset, len);
292 sb_end_write(inode->i_sb);
296 SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
298 struct fd f = fdget(fd);
302 error = do_fallocate(f.file, mode, offset, len);
309 * access() needs to use the real uid/gid, not the effective uid/gid.
310 * We do this by temporarily clearing all FS-related capabilities and
311 * switching the fsuid/fsgid around to the real ones.
313 SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
315 const struct cred *old_cred;
316 struct cred *override_cred;
320 unsigned int lookup_flags = LOOKUP_FOLLOW;
322 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
325 override_cred = prepare_creds();
329 override_cred->fsuid = override_cred->uid;
330 override_cred->fsgid = override_cred->gid;
332 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
333 /* Clear the capabilities if we switch to a non-root user */
334 kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
335 if (!uid_eq(override_cred->uid, root_uid))
336 cap_clear(override_cred->cap_effective);
338 override_cred->cap_effective =
339 override_cred->cap_permitted;
342 old_cred = override_creds(override_cred);
344 res = user_path_at(dfd, filename, lookup_flags, &path);
348 inode = path.dentry->d_inode;
350 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
352 * MAY_EXEC on regular files is denied if the fs is mounted
353 * with the "noexec" flag.
356 if (path.mnt->mnt_flags & MNT_NOEXEC)
357 goto out_path_release;
360 res = inode_permission(inode, mode | MAY_ACCESS);
361 /* SuS v2 requires we report a read only fs too */
362 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
363 goto out_path_release;
365 * This is a rare case where using __mnt_is_readonly()
366 * is OK without a mnt_want/drop_write() pair. Since
367 * no actual write to the fs is performed here, we do
368 * not need to telegraph to that to anyone.
370 * By doing this, we accept that this access is
371 * inherently racy and know that the fs may change
372 * state before we even see this result.
374 if (__mnt_is_readonly(path.mnt))
379 if (retry_estale(res, lookup_flags)) {
380 lookup_flags |= LOOKUP_REVAL;
384 revert_creds(old_cred);
385 put_cred(override_cred);
389 SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
391 return sys_faccessat(AT_FDCWD, filename, mode);
394 SYSCALL_DEFINE1(chdir, const char __user *, filename)
398 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
400 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
404 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
408 set_fs_pwd(current->fs, &path);
412 if (retry_estale(error, lookup_flags)) {
413 lookup_flags |= LOOKUP_REVAL;
420 SYSCALL_DEFINE1(fchdir, unsigned int, fd)
422 struct fd f = fdget_raw(fd);
430 inode = file_inode(f.file);
433 if (!S_ISDIR(inode->i_mode))
436 error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
438 set_fs_pwd(current->fs, &f.file->f_path);
445 SYSCALL_DEFINE1(chroot, 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_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
460 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
462 error = security_path_chroot(&path);
466 set_fs_root(current->fs, &path);
470 if (retry_estale(error, lookup_flags)) {
471 lookup_flags |= LOOKUP_REVAL;
478 static int chmod_common(struct path *path, umode_t mode)
480 struct inode *inode = path->dentry->d_inode;
481 struct inode *delegated_inode = NULL;
482 struct iattr newattrs;
485 error = mnt_want_write(path->mnt);
489 mutex_lock(&inode->i_mutex);
490 error = security_path_chmod(path, mode);
493 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
494 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
495 error = notify_change(path->dentry, &newattrs, &delegated_inode);
497 mutex_unlock(&inode->i_mutex);
498 if (delegated_inode) {
499 error = break_deleg_wait(&delegated_inode);
503 mnt_drop_write(path->mnt);
507 SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
509 struct fd f = fdget(fd);
513 audit_inode(NULL, f.file->f_path.dentry, 0);
514 err = chmod_common(&f.file->f_path, mode);
520 SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
524 unsigned int lookup_flags = LOOKUP_FOLLOW;
526 error = user_path_at(dfd, filename, lookup_flags, &path);
528 error = chmod_common(&path, mode);
530 if (retry_estale(error, lookup_flags)) {
531 lookup_flags |= LOOKUP_REVAL;
538 SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
540 return sys_fchmodat(AT_FDCWD, filename, mode);
543 static int chown_common(struct path *path, uid_t user, gid_t group)
545 struct inode *inode = path->dentry->d_inode;
546 struct inode *delegated_inode = NULL;
548 struct iattr newattrs;
552 uid = make_kuid(current_user_ns(), user);
553 gid = make_kgid(current_user_ns(), group);
555 newattrs.ia_valid = ATTR_CTIME;
556 if (user != (uid_t) -1) {
559 newattrs.ia_valid |= ATTR_UID;
560 newattrs.ia_uid = uid;
562 if (group != (gid_t) -1) {
565 newattrs.ia_valid |= ATTR_GID;
566 newattrs.ia_gid = gid;
568 if (!S_ISDIR(inode->i_mode))
570 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
572 mutex_lock(&inode->i_mutex);
573 error = security_path_chown(path, uid, gid);
575 error = notify_change(path->dentry, &newattrs, &delegated_inode);
576 mutex_unlock(&inode->i_mutex);
577 if (delegated_inode) {
578 error = break_deleg_wait(&delegated_inode);
585 SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
586 gid_t, group, int, flag)
592 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
595 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
596 if (flag & AT_EMPTY_PATH)
597 lookup_flags |= LOOKUP_EMPTY;
599 error = user_path_at(dfd, filename, lookup_flags, &path);
602 error = mnt_want_write(path.mnt);
605 error = chown_common(&path, user, group);
606 mnt_drop_write(path.mnt);
609 if (retry_estale(error, lookup_flags)) {
610 lookup_flags |= LOOKUP_REVAL;
617 SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
619 return sys_fchownat(AT_FDCWD, filename, user, group, 0);
622 SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
624 return sys_fchownat(AT_FDCWD, filename, user, group,
625 AT_SYMLINK_NOFOLLOW);
628 SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
630 struct fd f = fdget(fd);
636 error = mnt_want_write_file(f.file);
639 audit_inode(NULL, f.file->f_path.dentry, 0);
640 error = chown_common(&f.file->f_path, user, group);
641 mnt_drop_write_file(f.file);
649 * You have to be very careful that these write
650 * counts get cleaned up in error cases and
651 * upon __fput(). This should probably never
652 * be called outside of __dentry_open().
654 static inline int __get_file_write_access(struct inode *inode,
655 struct vfsmount *mnt)
658 error = get_write_access(inode);
662 * Do not take mount writer counts on
663 * special files since no writes to
664 * the mount itself will occur.
666 if (!special_file(inode->i_mode)) {
668 * Balanced in __fput()
670 error = __mnt_want_write(mnt);
672 put_write_access(inode);
677 int open_check_o_direct(struct file *f)
679 /* NB: we're sure to have correct a_ops only after f_op->open */
680 if (f->f_flags & O_DIRECT) {
681 if (!f->f_mapping->a_ops ||
682 ((!f->f_mapping->a_ops->direct_IO) &&
683 (!f->f_mapping->a_ops->get_xip_mem))) {
690 static int do_dentry_open(struct file *f,
691 int (*open)(struct inode *, struct file *),
692 const struct cred *cred)
694 static const struct file_operations empty_fops = {};
698 f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
699 FMODE_PREAD | FMODE_PWRITE;
701 if (unlikely(f->f_flags & O_PATH))
702 f->f_mode = FMODE_PATH;
704 path_get(&f->f_path);
705 inode = f->f_inode = f->f_path.dentry->d_inode;
706 if (f->f_mode & FMODE_WRITE) {
707 error = __get_file_write_access(inode, f->f_path.mnt);
710 if (!special_file(inode->i_mode))
714 f->f_mapping = inode->i_mapping;
716 if (unlikely(f->f_mode & FMODE_PATH)) {
717 f->f_op = &empty_fops;
721 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
722 if (S_ISREG(inode->i_mode))
723 f->f_mode |= FMODE_ATOMIC_POS;
725 f->f_op = fops_get(inode->i_fop);
726 if (unlikely(WARN_ON(!f->f_op))) {
731 error = security_file_open(f, cred);
735 error = break_lease(inode, f->f_flags);
740 open = f->f_op->open;
742 error = open(inode, f);
746 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
747 i_readcount_inc(inode);
749 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
751 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
757 if (f->f_mode & FMODE_WRITE) {
758 put_write_access(inode);
759 if (!special_file(inode->i_mode)) {
761 * We don't consider this a real
762 * mnt_want/drop_write() pair
763 * because it all happenend right
764 * here, so just reset the state.
767 __mnt_drop_write(f->f_path.mnt);
771 path_put(&f->f_path);
772 f->f_path.mnt = NULL;
773 f->f_path.dentry = NULL;
779 * finish_open - finish opening a file
780 * @file: file pointer
781 * @dentry: pointer to dentry
782 * @open: open callback
783 * @opened: state of open
785 * This can be used to finish opening a file passed to i_op->atomic_open().
787 * If the open callback is set to NULL, then the standard f_op->open()
788 * filesystem callback is substituted.
790 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
791 * the return value of d_splice_alias(), then the caller needs to perform dput()
792 * on it after finish_open().
794 * On successful return @file is a fully instantiated open file. After this, if
795 * an error occurs in ->atomic_open(), it needs to clean up with fput().
797 * Returns zero on success or -errno if the open failed.
799 int finish_open(struct file *file, struct dentry *dentry,
800 int (*open)(struct inode *, struct file *),
804 BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
806 file->f_path.dentry = dentry;
807 error = do_dentry_open(file, open, current_cred());
809 *opened |= FILE_OPENED;
813 EXPORT_SYMBOL(finish_open);
816 * finish_no_open - finish ->atomic_open() without opening the file
818 * @file: file pointer
819 * @dentry: dentry or NULL (as returned from ->lookup())
821 * This can be used to set the result of a successful lookup in ->atomic_open().
823 * NB: unlike finish_open() this function does consume the dentry reference and
824 * the caller need not dput() it.
826 * Returns "1" which must be the return value of ->atomic_open() after having
827 * called this function.
829 int finish_no_open(struct file *file, struct dentry *dentry)
831 file->f_path.dentry = dentry;
834 EXPORT_SYMBOL(finish_no_open);
836 struct file *dentry_open(const struct path *path, int flags,
837 const struct cred *cred)
842 validate_creds(cred);
844 /* We must always pass in a valid mount pointer. */
847 f = get_empty_filp();
851 error = do_dentry_open(f, NULL, cred);
853 /* from now on we need fput() to dispose of f */
854 error = open_check_o_direct(f);
866 EXPORT_SYMBOL(dentry_open);
868 static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
870 int lookup_flags = 0;
873 if (flags & (O_CREAT | __O_TMPFILE))
874 op->mode = (mode & S_IALLUGO) | S_IFREG;
878 /* Must never be set by userspace */
879 flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
882 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
883 * check for O_DSYNC if the need any syncing at all we enforce it's
884 * always set instead of having to deal with possibly weird behaviour
885 * for malicious applications setting only __O_SYNC.
887 if (flags & __O_SYNC)
890 if (flags & __O_TMPFILE) {
891 if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
893 acc_mode = MAY_OPEN | ACC_MODE(flags);
894 if (!(acc_mode & MAY_WRITE))
896 } else if (flags & O_PATH) {
898 * If we have O_PATH in the open flag. Then we
899 * cannot have anything other than the below set of flags
901 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
904 acc_mode = MAY_OPEN | ACC_MODE(flags);
907 op->open_flag = flags;
909 /* O_TRUNC implies we need access checks for write permissions */
911 acc_mode |= MAY_WRITE;
913 /* Allow the LSM permission hook to distinguish append
914 access from general write access. */
915 if (flags & O_APPEND)
916 acc_mode |= MAY_APPEND;
918 op->acc_mode = acc_mode;
920 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
922 if (flags & O_CREAT) {
923 op->intent |= LOOKUP_CREATE;
925 op->intent |= LOOKUP_EXCL;
928 if (flags & O_DIRECTORY)
929 lookup_flags |= LOOKUP_DIRECTORY;
930 if (!(flags & O_NOFOLLOW))
931 lookup_flags |= LOOKUP_FOLLOW;
932 op->lookup_flags = lookup_flags;
937 * file_open_name - open file and return file pointer
939 * @name: struct filename containing path to open
940 * @flags: open flags as per the open(2) second argument
941 * @mode: mode for the new file if O_CREAT is set, else ignored
943 * This is the helper to open a file from kernelspace if you really
944 * have to. But in generally you should not do this, so please move
945 * along, nothing to see here..
947 struct file *file_open_name(struct filename *name, int flags, umode_t mode)
949 struct open_flags op;
950 int err = build_open_flags(flags, mode, &op);
951 return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op);
955 * filp_open - open file and return file pointer
957 * @filename: path to open
958 * @flags: open flags as per the open(2) second argument
959 * @mode: mode for the new file if O_CREAT is set, else ignored
961 * This is the helper to open a file from kernelspace if you really
962 * have to. But in generally you should not do this, so please move
963 * along, nothing to see here..
965 struct file *filp_open(const char *filename, int flags, umode_t mode)
967 struct filename name = {.name = filename};
968 return file_open_name(&name, flags, mode);
970 EXPORT_SYMBOL(filp_open);
972 struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
973 const char *filename, int flags)
975 struct open_flags op;
976 int err = build_open_flags(flags, 0, &op);
980 return ERR_PTR(-EINVAL);
981 if (!filename && (flags & O_DIRECTORY))
982 if (!dentry->d_inode->i_op->lookup)
983 return ERR_PTR(-ENOTDIR);
984 return do_file_open_root(dentry, mnt, filename, &op);
986 EXPORT_SYMBOL(file_open_root);
988 long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
990 struct open_flags op;
991 int fd = build_open_flags(flags, mode, &op);
992 struct filename *tmp;
997 tmp = getname(filename);
1001 fd = get_unused_fd_flags(flags);
1003 struct file *f = do_filp_open(dfd, tmp, &op);
1016 SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
1018 if (force_o_largefile())
1019 flags |= O_LARGEFILE;
1021 return do_sys_open(AT_FDCWD, filename, flags, mode);
1024 SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
1027 if (force_o_largefile())
1028 flags |= O_LARGEFILE;
1030 return do_sys_open(dfd, filename, flags, mode);
1036 * For backward compatibility? Maybe this should be moved
1037 * into arch/i386 instead?
1039 SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
1041 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1047 * "id" is the POSIX thread ID. We use the
1048 * files pointer for this..
1050 int filp_close(struct file *filp, fl_owner_t id)
1054 if (!file_count(filp)) {
1055 printk(KERN_ERR "VFS: Close: file count is 0\n");
1059 if (filp->f_op->flush)
1060 retval = filp->f_op->flush(filp, id);
1062 if (likely(!(filp->f_mode & FMODE_PATH))) {
1063 dnotify_flush(filp, id);
1064 locks_remove_posix(filp, id);
1070 EXPORT_SYMBOL(filp_close);
1073 * Careful here! We test whether the file pointer is NULL before
1074 * releasing the fd. This ensures that one clone task can't release
1075 * an fd while another clone is opening it.
1077 SYSCALL_DEFINE1(close, unsigned int, fd)
1079 int retval = __close_fd(current->files, fd);
1081 /* can't restart close syscall because file table entry was cleared */
1082 if (unlikely(retval == -ERESTARTSYS ||
1083 retval == -ERESTARTNOINTR ||
1084 retval == -ERESTARTNOHAND ||
1085 retval == -ERESTART_RESTARTBLOCK))
1090 EXPORT_SYMBOL(sys_close);
1093 * This routine simulates a hangup on the tty, to arrange that users
1094 * are given clean terminals at login time.
1096 SYSCALL_DEFINE0(vhangup)
1098 if (capable(CAP_SYS_TTY_CONFIG)) {
1106 * Called when an inode is about to be open.
1107 * We use this to disallow opening large files on 32bit systems if
1108 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1109 * on this flag in sys_open.
1111 int generic_file_open(struct inode * inode, struct file * filp)
1113 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1118 EXPORT_SYMBOL(generic_file_open);
1121 * This is used by subsystems that don't want seekable
1122 * file descriptors. The function is not supposed to ever fail, the only
1123 * reason it returns an 'int' and not 'void' is so that it can be plugged
1124 * directly into file_operations structure.
1126 int nonseekable_open(struct inode *inode, struct file *filp)
1128 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1132 EXPORT_SYMBOL(nonseekable_open);