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 long vfs_truncate(struct path *path, loff_t length)
69 inode = path->dentry->d_inode;
71 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
72 if (S_ISDIR(inode->i_mode))
74 if (!S_ISREG(inode->i_mode))
77 error = mnt_want_write(path->mnt);
81 error = inode_permission(inode, MAY_WRITE);
83 goto mnt_drop_write_and_out;
87 goto mnt_drop_write_and_out;
89 error = get_write_access(inode);
91 goto mnt_drop_write_and_out;
94 * Make sure that there are no leases. get_write_access() protects
95 * against the truncate racing with a lease-granting setlease().
97 error = break_lease(inode, O_WRONLY);
99 goto put_write_and_out;
101 error = locks_verify_truncate(inode, NULL, length);
103 error = security_path_truncate(path);
105 error = do_truncate(path->dentry, length, 0, NULL);
108 put_write_access(inode);
109 mnt_drop_write_and_out:
110 mnt_drop_write(path->mnt);
114 EXPORT_SYMBOL_GPL(vfs_truncate);
116 static long do_sys_truncate(const char __user *pathname, loff_t length)
118 unsigned int lookup_flags = LOOKUP_FOLLOW;
122 if (length < 0) /* sorry, but loff_t says... */
126 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
128 error = vfs_truncate(&path, length);
131 if (retry_estale(error, lookup_flags)) {
132 lookup_flags |= LOOKUP_REVAL;
138 SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
140 return do_sys_truncate(path, length);
143 static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
146 struct dentry *dentry;
158 /* explicitly opened as large or we are on 64-bit box */
159 if (f.file->f_flags & O_LARGEFILE)
162 dentry = f.file->f_path.dentry;
163 inode = dentry->d_inode;
165 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
169 /* Cannot ftruncate over 2^31 bytes without large file support */
170 if (small && length > MAX_NON_LFS)
174 if (IS_APPEND(inode))
177 sb_start_write(inode->i_sb);
178 error = locks_verify_truncate(inode, f.file, length);
180 error = security_path_truncate(&f.file->f_path);
182 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
183 sb_end_write(inode->i_sb);
190 SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
192 long ret = do_sys_ftruncate(fd, length, 1);
193 /* avoid REGPARM breakage on x86: */
194 asmlinkage_protect(2, ret, fd, length);
198 /* LFS versions of truncate are only needed on 32 bit machines */
199 #if BITS_PER_LONG == 32
200 SYSCALL_DEFINE(truncate64)(const char __user * path, loff_t length)
202 return do_sys_truncate(path, length);
204 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
205 asmlinkage long SyS_truncate64(long path, loff_t length)
207 return SYSC_truncate64((const char __user *) path, length);
209 SYSCALL_ALIAS(sys_truncate64, SyS_truncate64);
212 SYSCALL_DEFINE(ftruncate64)(unsigned int fd, loff_t length)
214 long ret = do_sys_ftruncate(fd, length, 0);
215 /* avoid REGPARM breakage on x86: */
216 asmlinkage_protect(2, ret, fd, length);
219 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
220 asmlinkage long SyS_ftruncate64(long fd, loff_t length)
222 return SYSC_ftruncate64((unsigned int) fd, length);
224 SYSCALL_ALIAS(sys_ftruncate64, SyS_ftruncate64);
226 #endif /* BITS_PER_LONG == 32 */
229 int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
231 struct inode *inode = file->f_path.dentry->d_inode;
234 if (offset < 0 || len <= 0)
237 /* Return error if mode is not supported */
238 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
241 /* Punch hole must have keep size set */
242 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
243 !(mode & FALLOC_FL_KEEP_SIZE))
246 if (!(file->f_mode & FMODE_WRITE))
249 /* It's not possible punch hole on append only file */
250 if (mode & FALLOC_FL_PUNCH_HOLE && IS_APPEND(inode))
253 if (IS_IMMUTABLE(inode))
257 * Revalidate the write permissions, in case security policy has
258 * changed since the files were opened.
260 ret = security_file_permission(file, MAY_WRITE);
264 if (S_ISFIFO(inode->i_mode))
268 * Let individual file system decide if it supports preallocation
269 * for directories or not.
271 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
274 /* Check for wrap through zero too */
275 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
278 if (!file->f_op->fallocate)
281 sb_start_write(inode->i_sb);
282 ret = file->f_op->fallocate(file, mode, offset, len);
283 sb_end_write(inode->i_sb);
287 SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)
289 struct fd f = fdget(fd);
293 error = do_fallocate(f.file, mode, offset, len);
299 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
300 asmlinkage long SyS_fallocate(long fd, long mode, loff_t offset, loff_t len)
302 return SYSC_fallocate((int)fd, (int)mode, offset, len);
304 SYSCALL_ALIAS(sys_fallocate, SyS_fallocate);
308 * access() needs to use the real uid/gid, not the effective uid/gid.
309 * We do this by temporarily clearing all FS-related capabilities and
310 * switching the fsuid/fsgid around to the real ones.
312 SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
314 const struct cred *old_cred;
315 struct cred *override_cred;
319 unsigned int lookup_flags = LOOKUP_FOLLOW;
321 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
324 override_cred = prepare_creds();
328 override_cred->fsuid = override_cred->uid;
329 override_cred->fsgid = override_cred->gid;
331 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
332 /* Clear the capabilities if we switch to a non-root user */
333 kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
334 if (!uid_eq(override_cred->uid, root_uid))
335 cap_clear(override_cred->cap_effective);
337 override_cred->cap_effective =
338 override_cred->cap_permitted;
341 old_cred = override_creds(override_cred);
343 res = user_path_at(dfd, filename, lookup_flags, &path);
347 inode = path.dentry->d_inode;
349 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
351 * MAY_EXEC on regular files is denied if the fs is mounted
352 * with the "noexec" flag.
355 if (path.mnt->mnt_flags & MNT_NOEXEC)
356 goto out_path_release;
359 res = inode_permission(inode, mode | MAY_ACCESS);
360 /* SuS v2 requires we report a read only fs too */
361 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
362 goto out_path_release;
364 * This is a rare case where using __mnt_is_readonly()
365 * is OK without a mnt_want/drop_write() pair. Since
366 * no actual write to the fs is performed here, we do
367 * not need to telegraph to that to anyone.
369 * By doing this, we accept that this access is
370 * inherently racy and know that the fs may change
371 * state before we even see this result.
373 if (__mnt_is_readonly(path.mnt))
378 if (retry_estale(res, lookup_flags)) {
379 lookup_flags |= LOOKUP_REVAL;
383 revert_creds(old_cred);
384 put_cred(override_cred);
388 SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
390 return sys_faccessat(AT_FDCWD, filename, mode);
393 SYSCALL_DEFINE1(chdir, const char __user *, filename)
398 error = user_path_dir(filename, &path);
402 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
406 set_fs_pwd(current->fs, &path);
414 SYSCALL_DEFINE1(fchdir, unsigned int, fd)
416 struct fd f = fdget_raw(fd);
424 inode = f.file->f_path.dentry->d_inode;
427 if (!S_ISDIR(inode->i_mode))
430 error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
432 set_fs_pwd(current->fs, &f.file->f_path);
439 SYSCALL_DEFINE1(chroot, const char __user *, filename)
444 error = user_path_dir(filename, &path);
448 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
453 if (!nsown_capable(CAP_SYS_CHROOT))
455 error = security_path_chroot(&path);
459 set_fs_root(current->fs, &path);
467 static int chmod_common(struct path *path, umode_t mode)
469 struct inode *inode = path->dentry->d_inode;
470 struct iattr newattrs;
473 error = mnt_want_write(path->mnt);
476 mutex_lock(&inode->i_mutex);
477 error = security_path_chmod(path, mode);
480 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
481 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
482 error = notify_change(path->dentry, &newattrs);
484 mutex_unlock(&inode->i_mutex);
485 mnt_drop_write(path->mnt);
489 SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
496 audit_inode(NULL, file->f_path.dentry, 0);
497 err = chmod_common(&file->f_path, mode);
503 SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
508 error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
510 error = chmod_common(&path, mode);
516 SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
518 return sys_fchmodat(AT_FDCWD, filename, mode);
521 static int chown_common(struct path *path, uid_t user, gid_t group)
523 struct inode *inode = path->dentry->d_inode;
525 struct iattr newattrs;
529 uid = make_kuid(current_user_ns(), user);
530 gid = make_kgid(current_user_ns(), group);
532 newattrs.ia_valid = ATTR_CTIME;
533 if (user != (uid_t) -1) {
536 newattrs.ia_valid |= ATTR_UID;
537 newattrs.ia_uid = uid;
539 if (group != (gid_t) -1) {
542 newattrs.ia_valid |= ATTR_GID;
543 newattrs.ia_gid = gid;
545 if (!S_ISDIR(inode->i_mode))
547 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
548 mutex_lock(&inode->i_mutex);
549 error = security_path_chown(path, uid, gid);
551 error = notify_change(path->dentry, &newattrs);
552 mutex_unlock(&inode->i_mutex);
557 SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
558 gid_t, group, int, flag)
564 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
567 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
568 if (flag & AT_EMPTY_PATH)
569 lookup_flags |= LOOKUP_EMPTY;
570 error = user_path_at(dfd, filename, lookup_flags, &path);
573 error = mnt_want_write(path.mnt);
576 error = chown_common(&path, user, group);
577 mnt_drop_write(path.mnt);
584 SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
586 return sys_fchownat(AT_FDCWD, filename, user, group, 0);
589 SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
591 return sys_fchownat(AT_FDCWD, filename, user, group,
592 AT_SYMLINK_NOFOLLOW);
595 SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
597 struct fd f = fdget(fd);
603 error = mnt_want_write_file(f.file);
606 audit_inode(NULL, f.file->f_path.dentry, 0);
607 error = chown_common(&f.file->f_path, user, group);
608 mnt_drop_write_file(f.file);
616 * You have to be very careful that these write
617 * counts get cleaned up in error cases and
618 * upon __fput(). This should probably never
619 * be called outside of __dentry_open().
621 static inline int __get_file_write_access(struct inode *inode,
622 struct vfsmount *mnt)
625 error = get_write_access(inode);
629 * Do not take mount writer counts on
630 * special files since no writes to
631 * the mount itself will occur.
633 if (!special_file(inode->i_mode)) {
635 * Balanced in __fput()
637 error = __mnt_want_write(mnt);
639 put_write_access(inode);
644 int open_check_o_direct(struct file *f)
646 /* NB: we're sure to have correct a_ops only after f_op->open */
647 if (f->f_flags & O_DIRECT) {
648 if (!f->f_mapping->a_ops ||
649 ((!f->f_mapping->a_ops->direct_IO) &&
650 (!f->f_mapping->a_ops->get_xip_mem))) {
657 static int do_dentry_open(struct file *f,
658 int (*open)(struct inode *, struct file *),
659 const struct cred *cred)
661 static const struct file_operations empty_fops = {};
665 f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
666 FMODE_PREAD | FMODE_PWRITE;
668 if (unlikely(f->f_flags & O_PATH))
669 f->f_mode = FMODE_PATH;
671 path_get(&f->f_path);
672 inode = f->f_path.dentry->d_inode;
673 if (f->f_mode & FMODE_WRITE) {
674 error = __get_file_write_access(inode, f->f_path.mnt);
677 if (!special_file(inode->i_mode))
681 f->f_mapping = inode->i_mapping;
683 file_sb_list_add(f, inode->i_sb);
685 if (unlikely(f->f_mode & FMODE_PATH)) {
686 f->f_op = &empty_fops;
690 f->f_op = fops_get(inode->i_fop);
692 error = security_file_open(f, cred);
696 error = break_lease(inode, f->f_flags);
700 if (!open && f->f_op)
701 open = f->f_op->open;
703 error = open(inode, f);
707 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
708 i_readcount_inc(inode);
710 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
712 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
719 if (f->f_mode & FMODE_WRITE) {
720 put_write_access(inode);
721 if (!special_file(inode->i_mode)) {
723 * We don't consider this a real
724 * mnt_want/drop_write() pair
725 * because it all happenend right
726 * here, so just reset the state.
729 __mnt_drop_write(f->f_path.mnt);
733 path_put(&f->f_path);
734 f->f_path.mnt = NULL;
735 f->f_path.dentry = NULL;
740 * finish_open - finish opening a file
741 * @od: opaque open data
742 * @dentry: pointer to dentry
743 * @open: open callback
745 * This can be used to finish opening a file passed to i_op->atomic_open().
747 * If the open callback is set to NULL, then the standard f_op->open()
748 * filesystem callback is substituted.
750 int finish_open(struct file *file, struct dentry *dentry,
751 int (*open)(struct inode *, struct file *),
755 BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
757 file->f_path.dentry = dentry;
758 error = do_dentry_open(file, open, current_cred());
760 *opened |= FILE_OPENED;
764 EXPORT_SYMBOL(finish_open);
767 * finish_no_open - finish ->atomic_open() without opening the file
769 * @od: opaque open data
770 * @dentry: dentry or NULL (as returned from ->lookup())
772 * This can be used to set the result of a successful lookup in ->atomic_open().
773 * The filesystem's atomic_open() method shall return NULL after calling this.
775 int finish_no_open(struct file *file, struct dentry *dentry)
777 file->f_path.dentry = dentry;
780 EXPORT_SYMBOL(finish_no_open);
782 struct file *dentry_open(const struct path *path, int flags,
783 const struct cred *cred)
788 validate_creds(cred);
790 /* We must always pass in a valid mount pointer. */
794 f = get_empty_filp();
796 return ERR_PTR(error);
800 error = do_dentry_open(f, NULL, cred);
802 error = open_check_o_direct(f);
813 EXPORT_SYMBOL(dentry_open);
815 static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
817 int lookup_flags = 0;
821 op->mode = (mode & S_IALLUGO) | S_IFREG;
825 /* Must never be set by userspace */
826 flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
829 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
830 * check for O_DSYNC if the need any syncing at all we enforce it's
831 * always set instead of having to deal with possibly weird behaviour
832 * for malicious applications setting only __O_SYNC.
834 if (flags & __O_SYNC)
838 * If we have O_PATH in the open flag. Then we
839 * cannot have anything other than the below set of flags
841 if (flags & O_PATH) {
842 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
845 acc_mode = MAY_OPEN | ACC_MODE(flags);
848 op->open_flag = flags;
850 /* O_TRUNC implies we need access checks for write permissions */
852 acc_mode |= MAY_WRITE;
854 /* Allow the LSM permission hook to distinguish append
855 access from general write access. */
856 if (flags & O_APPEND)
857 acc_mode |= MAY_APPEND;
859 op->acc_mode = acc_mode;
861 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
863 if (flags & O_CREAT) {
864 op->intent |= LOOKUP_CREATE;
866 op->intent |= LOOKUP_EXCL;
869 if (flags & O_DIRECTORY)
870 lookup_flags |= LOOKUP_DIRECTORY;
871 if (!(flags & O_NOFOLLOW))
872 lookup_flags |= LOOKUP_FOLLOW;
877 * file_open_name - open file and return file pointer
879 * @name: struct filename containing path to open
880 * @flags: open flags as per the open(2) second argument
881 * @mode: mode for the new file if O_CREAT is set, else ignored
883 * This is the helper to open a file from kernelspace if you really
884 * have to. But in generally you should not do this, so please move
885 * along, nothing to see here..
887 struct file *file_open_name(struct filename *name, int flags, umode_t mode)
889 struct open_flags op;
890 int lookup = build_open_flags(flags, mode, &op);
891 return do_filp_open(AT_FDCWD, name, &op, lookup);
895 * filp_open - open file and return file pointer
897 * @filename: path to open
898 * @flags: open flags as per the open(2) second argument
899 * @mode: mode for the new file if O_CREAT is set, else ignored
901 * This is the helper to open a file from kernelspace if you really
902 * have to. But in generally you should not do this, so please move
903 * along, nothing to see here..
905 struct file *filp_open(const char *filename, int flags, umode_t mode)
907 struct filename name = {.name = filename};
908 return file_open_name(&name, flags, mode);
910 EXPORT_SYMBOL(filp_open);
912 struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
913 const char *filename, int flags)
915 struct open_flags op;
916 int lookup = build_open_flags(flags, 0, &op);
918 return ERR_PTR(-EINVAL);
919 if (!filename && (flags & O_DIRECTORY))
920 if (!dentry->d_inode->i_op->lookup)
921 return ERR_PTR(-ENOTDIR);
922 return do_file_open_root(dentry, mnt, filename, &op, lookup);
924 EXPORT_SYMBOL(file_open_root);
926 long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
928 struct open_flags op;
929 int lookup = build_open_flags(flags, mode, &op);
930 struct filename *tmp = getname(filename);
931 int fd = PTR_ERR(tmp);
934 fd = get_unused_fd_flags(flags);
936 struct file *f = do_filp_open(dfd, tmp, &op, lookup);
950 SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
954 if (force_o_largefile())
955 flags |= O_LARGEFILE;
957 ret = do_sys_open(AT_FDCWD, filename, flags, mode);
958 /* avoid REGPARM breakage on x86: */
959 asmlinkage_protect(3, ret, filename, flags, mode);
963 SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
968 if (force_o_largefile())
969 flags |= O_LARGEFILE;
971 ret = do_sys_open(dfd, filename, flags, mode);
972 /* avoid REGPARM breakage on x86: */
973 asmlinkage_protect(4, ret, dfd, filename, flags, mode);
980 * For backward compatibility? Maybe this should be moved
981 * into arch/i386 instead?
983 SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
985 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
991 * "id" is the POSIX thread ID. We use the
992 * files pointer for this..
994 int filp_close(struct file *filp, fl_owner_t id)
998 if (!file_count(filp)) {
999 printk(KERN_ERR "VFS: Close: file count is 0\n");
1003 if (filp->f_op && filp->f_op->flush)
1004 retval = filp->f_op->flush(filp, id);
1006 if (likely(!(filp->f_mode & FMODE_PATH))) {
1007 dnotify_flush(filp, id);
1008 locks_remove_posix(filp, id);
1014 EXPORT_SYMBOL(filp_close);
1017 * Careful here! We test whether the file pointer is NULL before
1018 * releasing the fd. This ensures that one clone task can't release
1019 * an fd while another clone is opening it.
1021 SYSCALL_DEFINE1(close, unsigned int, fd)
1023 int retval = __close_fd(current->files, fd);
1025 /* can't restart close syscall because file table entry was cleared */
1026 if (unlikely(retval == -ERESTARTSYS ||
1027 retval == -ERESTARTNOINTR ||
1028 retval == -ERESTARTNOHAND ||
1029 retval == -ERESTART_RESTARTBLOCK))
1034 EXPORT_SYMBOL(sys_close);
1037 * This routine simulates a hangup on the tty, to arrange that users
1038 * are given clean terminals at login time.
1040 SYSCALL_DEFINE0(vhangup)
1042 if (capable(CAP_SYS_TTY_CONFIG)) {
1050 * Called when an inode is about to be open.
1051 * We use this to disallow opening large files on 32bit systems if
1052 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1053 * on this flag in sys_open.
1055 int generic_file_open(struct inode * inode, struct file * filp)
1057 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1062 EXPORT_SYMBOL(generic_file_open);
1065 * This is used by subsystems that don't want seekable
1066 * file descriptors. The function is not supposed to ever fail, the only
1067 * reason it returns an 'int' and not 'void' is so that it can be plugged
1068 * directly into file_operations structure.
1070 int nonseekable_open(struct inode *inode, struct file *filp)
1072 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1076 EXPORT_SYMBOL(nonseekable_open);