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1/*
2 * linux/fs/open.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/string.h>
8#include <linux/mm.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 <linux/uaccess.h>
23#include <linux/fs.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>
34
35#include "internal.h"
36
37int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
38 struct file *filp)
39{
40 int ret;
41 struct iattr newattrs;
42
43 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
44 if (length < 0)
45 return -EINVAL;
46
47 newattrs.ia_size = length;
48 newattrs.ia_valid = ATTR_SIZE | time_attrs;
49 if (filp) {
50 newattrs.ia_file = filp;
51 newattrs.ia_valid |= ATTR_FILE;
52 }
53
54 /* Remove suid, sgid, and file capabilities on truncate too */
55 ret = dentry_needs_remove_privs(dentry);
56 if (ret < 0)
57 return ret;
58 if (ret)
59 newattrs.ia_valid |= ret | ATTR_FORCE;
60
61 inode_lock(dentry->d_inode);
62 /* Note any delegations or leases have already been broken: */
63 ret = notify_change(dentry, &newattrs, NULL);
64 inode_unlock(dentry->d_inode);
65 return ret;
66}
67
68long vfs_truncate(const struct path *path, loff_t length)
69{
70 struct inode *inode;
71 struct dentry *upperdentry;
72 long error;
73
74 inode = path->dentry->d_inode;
75
76 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
77 if (S_ISDIR(inode->i_mode))
78 return -EISDIR;
79 if (!S_ISREG(inode->i_mode))
80 return -EINVAL;
81
82 error = mnt_want_write(path->mnt);
83 if (error)
84 goto out;
85
86 error = inode_permission(inode, MAY_WRITE);
87 if (error)
88 goto mnt_drop_write_and_out;
89
90 error = -EPERM;
91 if (IS_APPEND(inode))
92 goto mnt_drop_write_and_out;
93
94 /*
95 * If this is an overlayfs then do as if opening the file so we get
96 * write access on the upper inode, not on the overlay inode. For
97 * non-overlay filesystems d_real() is an identity function.
98 */
99 upperdentry = d_real(path->dentry, NULL, O_WRONLY, 0);
100 error = PTR_ERR(upperdentry);
101 if (IS_ERR(upperdentry))
102 goto mnt_drop_write_and_out;
103
104 error = get_write_access(upperdentry->d_inode);
105 if (error)
106 goto mnt_drop_write_and_out;
107
108 /*
109 * Make sure that there are no leases. get_write_access() protects
110 * against the truncate racing with a lease-granting setlease().
111 */
112 error = break_lease(inode, O_WRONLY);
113 if (error)
114 goto put_write_and_out;
115
116 error = locks_verify_truncate(inode, NULL, length);
117 if (!error)
118 error = security_path_truncate(path);
119 if (!error)
120 error = do_truncate(path->dentry, length, 0, NULL);
121
122put_write_and_out:
123 put_write_access(upperdentry->d_inode);
124mnt_drop_write_and_out:
125 mnt_drop_write(path->mnt);
126out:
127 return error;
128}
129EXPORT_SYMBOL_GPL(vfs_truncate);
130
131long do_sys_truncate(const char __user *pathname, loff_t length)
132{
133 unsigned int lookup_flags = LOOKUP_FOLLOW;
134 struct path path;
135 int error;
136
137 if (length < 0) /* sorry, but loff_t says... */
138 return -EINVAL;
139
140retry:
141 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
142 if (!error) {
143 error = vfs_truncate(&path, length);
144 path_put(&path);
145 }
146 if (retry_estale(error, lookup_flags)) {
147 lookup_flags |= LOOKUP_REVAL;
148 goto retry;
149 }
150 return error;
151}
152
153SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
154{
155 return do_sys_truncate(path, length);
156}
157
158#ifdef CONFIG_COMPAT
159COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
160{
161 return do_sys_truncate(path, length);
162}
163#endif
164
165long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
166{
167 struct inode *inode;
168 struct dentry *dentry;
169 struct fd f;
170 int error;
171
172 error = -EINVAL;
173 if (length < 0)
174 goto out;
175 error = -EBADF;
176 f = fdget(fd);
177 if (!f.file)
178 goto out;
179
180 /* explicitly opened as large or we are on 64-bit box */
181 if (f.file->f_flags & O_LARGEFILE)
182 small = 0;
183
184 dentry = f.file->f_path.dentry;
185 inode = dentry->d_inode;
186 error = -EINVAL;
187 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
188 goto out_putf;
189
190 error = -EINVAL;
191 /* Cannot ftruncate over 2^31 bytes without large file support */
192 if (small && length > MAX_NON_LFS)
193 goto out_putf;
194
195 error = -EPERM;
196 /* Check IS_APPEND on real upper inode */
197 if (IS_APPEND(file_inode(f.file)))
198 goto out_putf;
199
200 sb_start_write(inode->i_sb);
201 error = locks_verify_truncate(inode, f.file, length);
202 if (!error)
203 error = security_path_truncate(&f.file->f_path);
204 if (!error)
205 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
206 sb_end_write(inode->i_sb);
207out_putf:
208 fdput(f);
209out:
210 return error;
211}
212
213SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
214{
215 return do_sys_ftruncate(fd, length, 1);
216}
217
218#ifdef CONFIG_COMPAT
219COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
220{
221 return do_sys_ftruncate(fd, length, 1);
222}
223#endif
224
225/* LFS versions of truncate are only needed on 32 bit machines */
226#if BITS_PER_LONG == 32
227SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
228{
229 return do_sys_truncate(path, length);
230}
231
232SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
233{
234 return do_sys_ftruncate(fd, length, 0);
235}
236#endif /* BITS_PER_LONG == 32 */
237
238
239int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
240{
241 struct inode *inode = file_inode(file);
242 long ret;
243
244 if (offset < 0 || len <= 0)
245 return -EINVAL;
246
247 /* Return error if mode is not supported */
248 if (mode & ~FALLOC_FL_SUPPORTED_MASK)
249 return -EOPNOTSUPP;
250
251 /* Punch hole and zero range are mutually exclusive */
252 if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
253 (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
254 return -EOPNOTSUPP;
255
256 /* Punch hole must have keep size set */
257 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
258 !(mode & FALLOC_FL_KEEP_SIZE))
259 return -EOPNOTSUPP;
260
261 /* Collapse range should only be used exclusively. */
262 if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
263 (mode & ~FALLOC_FL_COLLAPSE_RANGE))
264 return -EINVAL;
265
266 /* Insert range should only be used exclusively. */
267 if ((mode & FALLOC_FL_INSERT_RANGE) &&
268 (mode & ~FALLOC_FL_INSERT_RANGE))
269 return -EINVAL;
270
271 /* Unshare range should only be used with allocate mode. */
272 if ((mode & FALLOC_FL_UNSHARE_RANGE) &&
273 (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE)))
274 return -EINVAL;
275
276 if (!(file->f_mode & FMODE_WRITE))
277 return -EBADF;
278
279 /*
280 * We can only allow pure fallocate on append only files
281 */
282 if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
283 return -EPERM;
284
285 if (IS_IMMUTABLE(inode))
286 return -EPERM;
287
288 /*
289 * We cannot allow any fallocate operation on an active swapfile
290 */
291 if (IS_SWAPFILE(inode))
292 return -ETXTBSY;
293
294 /*
295 * Revalidate the write permissions, in case security policy has
296 * changed since the files were opened.
297 */
298 ret = security_file_permission(file, MAY_WRITE);
299 if (ret)
300 return ret;
301
302 if (S_ISFIFO(inode->i_mode))
303 return -ESPIPE;
304
305 if (S_ISDIR(inode->i_mode))
306 return -EISDIR;
307
308 if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
309 return -ENODEV;
310
311 /* Check for wrap through zero too */
312 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
313 return -EFBIG;
314
315 if (!file->f_op->fallocate)
316 return -EOPNOTSUPP;
317
318 file_start_write(file);
319 ret = file->f_op->fallocate(file, mode, offset, len);
320
321 /*
322 * Create inotify and fanotify events.
323 *
324 * To keep the logic simple always create events if fallocate succeeds.
325 * This implies that events are even created if the file size remains
326 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
327 */
328 if (ret == 0)
329 fsnotify_modify(file);
330
331 file_end_write(file);
332 return ret;
333}
334EXPORT_SYMBOL_GPL(vfs_fallocate);
335
336int ksys_fallocate(int fd, int mode, loff_t offset, loff_t len)
337{
338 struct fd f = fdget(fd);
339 int error = -EBADF;
340
341 if (f.file) {
342 error = vfs_fallocate(f.file, mode, offset, len);
343 fdput(f);
344 }
345 return error;
346}
347
348SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
349{
350 return ksys_fallocate(fd, mode, offset, len);
351}
352
353/*
354 * access() needs to use the real uid/gid, not the effective uid/gid.
355 * We do this by temporarily clearing all FS-related capabilities and
356 * switching the fsuid/fsgid around to the real ones.
357 */
358long do_faccessat(int dfd, const char __user *filename, int mode)
359{
360 const struct cred *old_cred;
361 struct cred *override_cred;
362 struct path path;
363 struct inode *inode;
364 int res;
365 unsigned int lookup_flags = LOOKUP_FOLLOW;
366
367 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
368 return -EINVAL;
369
370 override_cred = prepare_creds();
371 if (!override_cred)
372 return -ENOMEM;
373
374 override_cred->fsuid = override_cred->uid;
375 override_cred->fsgid = override_cred->gid;
376
377 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
378 /* Clear the capabilities if we switch to a non-root user */
379 kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
380 if (!uid_eq(override_cred->uid, root_uid))
381 cap_clear(override_cred->cap_effective);
382 else
383 override_cred->cap_effective =
384 override_cred->cap_permitted;
385 }
386
387 old_cred = override_creds(override_cred);
388retry:
389 res = user_path_at(dfd, filename, lookup_flags, &path);
390 if (res)
391 goto out;
392
393 inode = d_backing_inode(path.dentry);
394
395 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
396 /*
397 * MAY_EXEC on regular files is denied if the fs is mounted
398 * with the "noexec" flag.
399 */
400 res = -EACCES;
401 if (path_noexec(&path))
402 goto out_path_release;
403 }
404
405 res = inode_permission(inode, mode | MAY_ACCESS);
406 /* SuS v2 requires we report a read only fs too */
407 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
408 goto out_path_release;
409 /*
410 * This is a rare case where using __mnt_is_readonly()
411 * is OK without a mnt_want/drop_write() pair. Since
412 * no actual write to the fs is performed here, we do
413 * not need to telegraph to that to anyone.
414 *
415 * By doing this, we accept that this access is
416 * inherently racy and know that the fs may change
417 * state before we even see this result.
418 */
419 if (__mnt_is_readonly(path.mnt))
420 res = -EROFS;
421
422out_path_release:
423 path_put(&path);
424 if (retry_estale(res, lookup_flags)) {
425 lookup_flags |= LOOKUP_REVAL;
426 goto retry;
427 }
428out:
429 revert_creds(old_cred);
430 put_cred(override_cred);
431 return res;
432}
433
434SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
435{
436 return do_faccessat(dfd, filename, mode);
437}
438
439SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
440{
441 return do_faccessat(AT_FDCWD, filename, mode);
442}
443
444int ksys_chdir(const char __user *filename)
445{
446 struct path path;
447 int error;
448 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
449retry:
450 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
451 if (error)
452 goto out;
453
454 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
455 if (error)
456 goto dput_and_out;
457
458 set_fs_pwd(current->fs, &path);
459
460dput_and_out:
461 path_put(&path);
462 if (retry_estale(error, lookup_flags)) {
463 lookup_flags |= LOOKUP_REVAL;
464 goto retry;
465 }
466out:
467 return error;
468}
469
470SYSCALL_DEFINE1(chdir, const char __user *, filename)
471{
472 return ksys_chdir(filename);
473}
474
475SYSCALL_DEFINE1(fchdir, unsigned int, fd)
476{
477 struct fd f = fdget_raw(fd);
478 int error;
479
480 error = -EBADF;
481 if (!f.file)
482 goto out;
483
484 error = -ENOTDIR;
485 if (!d_can_lookup(f.file->f_path.dentry))
486 goto out_putf;
487
488 error = inode_permission(file_inode(f.file), MAY_EXEC | MAY_CHDIR);
489 if (!error)
490 set_fs_pwd(current->fs, &f.file->f_path);
491out_putf:
492 fdput(f);
493out:
494 return error;
495}
496
497int ksys_chroot(const char __user *filename)
498{
499 struct path path;
500 int error;
501 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
502retry:
503 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
504 if (error)
505 goto out;
506
507 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
508 if (error)
509 goto dput_and_out;
510
511 error = -EPERM;
512 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
513 goto dput_and_out;
514 error = security_path_chroot(&path);
515 if (error)
516 goto dput_and_out;
517
518 set_fs_root(current->fs, &path);
519 error = 0;
520dput_and_out:
521 path_put(&path);
522 if (retry_estale(error, lookup_flags)) {
523 lookup_flags |= LOOKUP_REVAL;
524 goto retry;
525 }
526out:
527 return error;
528}
529
530SYSCALL_DEFINE1(chroot, const char __user *, filename)
531{
532 return ksys_chroot(filename);
533}
534
535static int chmod_common(const struct path *path, umode_t mode)
536{
537 struct inode *inode = path->dentry->d_inode;
538 struct inode *delegated_inode = NULL;
539 struct iattr newattrs;
540 int error;
541
542 error = mnt_want_write(path->mnt);
543 if (error)
544 return error;
545retry_deleg:
546 inode_lock(inode);
547 error = security_path_chmod(path, mode);
548 if (error)
549 goto out_unlock;
550 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
551 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
552 error = notify_change(path->dentry, &newattrs, &delegated_inode);
553out_unlock:
554 inode_unlock(inode);
555 if (delegated_inode) {
556 error = break_deleg_wait(&delegated_inode);
557 if (!error)
558 goto retry_deleg;
559 }
560 mnt_drop_write(path->mnt);
561 return error;
562}
563
564int ksys_fchmod(unsigned int fd, umode_t mode)
565{
566 struct fd f = fdget(fd);
567 int err = -EBADF;
568
569 if (f.file) {
570 audit_file(f.file);
571 err = chmod_common(&f.file->f_path, mode);
572 fdput(f);
573 }
574 return err;
575}
576
577SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
578{
579 return ksys_fchmod(fd, mode);
580}
581
582int do_fchmodat(int dfd, const char __user *filename, umode_t mode)
583{
584 struct path path;
585 int error;
586 unsigned int lookup_flags = LOOKUP_FOLLOW;
587retry:
588 error = user_path_at(dfd, filename, lookup_flags, &path);
589 if (!error) {
590 error = chmod_common(&path, mode);
591 path_put(&path);
592 if (retry_estale(error, lookup_flags)) {
593 lookup_flags |= LOOKUP_REVAL;
594 goto retry;
595 }
596 }
597 return error;
598}
599
600SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename,
601 umode_t, mode)
602{
603 return do_fchmodat(dfd, filename, mode);
604}
605
606SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
607{
608 return do_fchmodat(AT_FDCWD, filename, mode);
609}
610
611static int chown_common(const struct path *path, uid_t user, gid_t group)
612{
613 struct inode *inode = path->dentry->d_inode;
614 struct inode *delegated_inode = NULL;
615 int error;
616 struct iattr newattrs;
617 kuid_t uid;
618 kgid_t gid;
619
620 uid = make_kuid(current_user_ns(), user);
621 gid = make_kgid(current_user_ns(), group);
622
623retry_deleg:
624 newattrs.ia_valid = ATTR_CTIME;
625 if (user != (uid_t) -1) {
626 if (!uid_valid(uid))
627 return -EINVAL;
628 newattrs.ia_valid |= ATTR_UID;
629 newattrs.ia_uid = uid;
630 }
631 if (group != (gid_t) -1) {
632 if (!gid_valid(gid))
633 return -EINVAL;
634 newattrs.ia_valid |= ATTR_GID;
635 newattrs.ia_gid = gid;
636 }
637 if (!S_ISDIR(inode->i_mode))
638 newattrs.ia_valid |=
639 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
640 inode_lock(inode);
641 error = security_path_chown(path, uid, gid);
642 if (!error)
643 error = notify_change(path->dentry, &newattrs, &delegated_inode);
644 inode_unlock(inode);
645 if (delegated_inode) {
646 error = break_deleg_wait(&delegated_inode);
647 if (!error)
648 goto retry_deleg;
649 }
650 return error;
651}
652
653int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
654 int flag)
655{
656 struct path path;
657 int error = -EINVAL;
658 int lookup_flags;
659
660 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
661 goto out;
662
663 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
664 if (flag & AT_EMPTY_PATH)
665 lookup_flags |= LOOKUP_EMPTY;
666retry:
667 error = user_path_at(dfd, filename, lookup_flags, &path);
668 if (error)
669 goto out;
670 error = mnt_want_write(path.mnt);
671 if (error)
672 goto out_release;
673 error = chown_common(&path, user, group);
674 mnt_drop_write(path.mnt);
675out_release:
676 path_put(&path);
677 if (retry_estale(error, lookup_flags)) {
678 lookup_flags |= LOOKUP_REVAL;
679 goto retry;
680 }
681out:
682 return error;
683}
684
685SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
686 gid_t, group, int, flag)
687{
688 return do_fchownat(dfd, filename, user, group, flag);
689}
690
691SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
692{
693 return do_fchownat(AT_FDCWD, filename, user, group, 0);
694}
695
696SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
697{
698 return do_fchownat(AT_FDCWD, filename, user, group,
699 AT_SYMLINK_NOFOLLOW);
700}
701
702int ksys_fchown(unsigned int fd, uid_t user, gid_t group)
703{
704 struct fd f = fdget(fd);
705 int error = -EBADF;
706
707 if (!f.file)
708 goto out;
709
710 error = mnt_want_write_file_path(f.file);
711 if (error)
712 goto out_fput;
713 audit_file(f.file);
714 error = chown_common(&f.file->f_path, user, group);
715 mnt_drop_write_file_path(f.file);
716out_fput:
717 fdput(f);
718out:
719 return error;
720}
721
722SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
723{
724 return ksys_fchown(fd, user, group);
725}
726
727int open_check_o_direct(struct file *f)
728{
729 /* NB: we're sure to have correct a_ops only after f_op->open */
730 if (f->f_flags & O_DIRECT) {
731 if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
732 return -EINVAL;
733 }
734 return 0;
735}
736
737static int do_dentry_open(struct file *f,
738 struct inode *inode,
739 int (*open)(struct inode *, struct file *),
740 const struct cred *cred)
741{
742 static const struct file_operations empty_fops = {};
743 int error;
744
745 f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
746 FMODE_PREAD | FMODE_PWRITE;
747
748 path_get(&f->f_path);
749 f->f_inode = inode;
750 f->f_mapping = inode->i_mapping;
751
752 /* Ensure that we skip any errors that predate opening of the file */
753 f->f_wb_err = filemap_sample_wb_err(f->f_mapping);
754
755 if (unlikely(f->f_flags & O_PATH)) {
756 f->f_mode = FMODE_PATH;
757 f->f_op = &empty_fops;
758 return 0;
759 }
760
761 if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
762 error = get_write_access(inode);
763 if (unlikely(error))
764 goto cleanup_file;
765 error = __mnt_want_write(f->f_path.mnt);
766 if (unlikely(error)) {
767 put_write_access(inode);
768 goto cleanup_file;
769 }
770 f->f_mode |= FMODE_WRITER;
771 }
772
773 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
774 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
775 f->f_mode |= FMODE_ATOMIC_POS;
776
777 f->f_op = fops_get(inode->i_fop);
778 if (unlikely(WARN_ON(!f->f_op))) {
779 error = -ENODEV;
780 goto cleanup_all;
781 }
782
783 error = security_file_open(f, cred);
784 if (error)
785 goto cleanup_all;
786
787 error = break_lease(locks_inode(f), f->f_flags);
788 if (error)
789 goto cleanup_all;
790
791 if (!open)
792 open = f->f_op->open;
793 if (open) {
794 error = open(inode, f);
795 if (error)
796 goto cleanup_all;
797 }
798 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
799 i_readcount_inc(inode);
800 if ((f->f_mode & FMODE_READ) &&
801 likely(f->f_op->read || f->f_op->read_iter))
802 f->f_mode |= FMODE_CAN_READ;
803 if ((f->f_mode & FMODE_WRITE) &&
804 likely(f->f_op->write || f->f_op->write_iter))
805 f->f_mode |= FMODE_CAN_WRITE;
806
807 f->f_write_hint = WRITE_LIFE_NOT_SET;
808 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
809
810 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
811
812 return 0;
813
814cleanup_all:
815 fops_put(f->f_op);
816 if (f->f_mode & FMODE_WRITER) {
817 put_write_access(inode);
818 __mnt_drop_write(f->f_path.mnt);
819 }
820cleanup_file:
821 path_put(&f->f_path);
822 f->f_path.mnt = NULL;
823 f->f_path.dentry = NULL;
824 f->f_inode = NULL;
825 return error;
826}
827
828/**
829 * finish_open - finish opening a file
830 * @file: file pointer
831 * @dentry: pointer to dentry
832 * @open: open callback
833 * @opened: state of open
834 *
835 * This can be used to finish opening a file passed to i_op->atomic_open().
836 *
837 * If the open callback is set to NULL, then the standard f_op->open()
838 * filesystem callback is substituted.
839 *
840 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
841 * the return value of d_splice_alias(), then the caller needs to perform dput()
842 * on it after finish_open().
843 *
844 * On successful return @file is a fully instantiated open file. After this, if
845 * an error occurs in ->atomic_open(), it needs to clean up with fput().
846 *
847 * Returns zero on success or -errno if the open failed.
848 */
849int finish_open(struct file *file, struct dentry *dentry,
850 int (*open)(struct inode *, struct file *),
851 int *opened)
852{
853 int error;
854 BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
855
856 file->f_path.dentry = dentry;
857 error = do_dentry_open(file, d_backing_inode(dentry), open,
858 current_cred());
859 if (!error)
860 *opened |= FILE_OPENED;
861
862 return error;
863}
864EXPORT_SYMBOL(finish_open);
865
866/**
867 * finish_no_open - finish ->atomic_open() without opening the file
868 *
869 * @file: file pointer
870 * @dentry: dentry or NULL (as returned from ->lookup())
871 *
872 * This can be used to set the result of a successful lookup in ->atomic_open().
873 *
874 * NB: unlike finish_open() this function does consume the dentry reference and
875 * the caller need not dput() it.
876 *
877 * Returns "1" which must be the return value of ->atomic_open() after having
878 * called this function.
879 */
880int finish_no_open(struct file *file, struct dentry *dentry)
881{
882 file->f_path.dentry = dentry;
883 return 1;
884}
885EXPORT_SYMBOL(finish_no_open);
886
887char *file_path(struct file *filp, char *buf, int buflen)
888{
889 return d_path(&filp->f_path, buf, buflen);
890}
891EXPORT_SYMBOL(file_path);
892
893/**
894 * vfs_open - open the file at the given path
895 * @path: path to open
896 * @file: newly allocated file with f_flag initialized
897 * @cred: credentials to use
898 */
899int vfs_open(const struct path *path, struct file *file,
900 const struct cred *cred)
901{
902 struct dentry *dentry = d_real(path->dentry, NULL, file->f_flags, 0);
903
904 if (IS_ERR(dentry))
905 return PTR_ERR(dentry);
906
907 file->f_path = *path;
908 return do_dentry_open(file, d_backing_inode(dentry), NULL, cred);
909}
910
911struct file *dentry_open(const struct path *path, int flags,
912 const struct cred *cred)
913{
914 int error;
915 struct file *f;
916
917 validate_creds(cred);
918
919 /* We must always pass in a valid mount pointer. */
920 BUG_ON(!path->mnt);
921
922 f = get_empty_filp();
923 if (!IS_ERR(f)) {
924 f->f_flags = flags;
925 error = vfs_open(path, f, cred);
926 if (!error) {
927 /* from now on we need fput() to dispose of f */
928 error = open_check_o_direct(f);
929 if (error) {
930 fput(f);
931 f = ERR_PTR(error);
932 }
933 } else {
934 put_filp(f);
935 f = ERR_PTR(error);
936 }
937 }
938 return f;
939}
940EXPORT_SYMBOL(dentry_open);
941
942static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
943{
944 int lookup_flags = 0;
945 int acc_mode = ACC_MODE(flags);
946
947 /*
948 * Clear out all open flags we don't know about so that we don't report
949 * them in fcntl(F_GETFD) or similar interfaces.
950 */
951 flags &= VALID_OPEN_FLAGS;
952
953 if (flags & (O_CREAT | __O_TMPFILE))
954 op->mode = (mode & S_IALLUGO) | S_IFREG;
955 else
956 op->mode = 0;
957
958 /* Must never be set by userspace */
959 flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
960
961 /*
962 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
963 * check for O_DSYNC if the need any syncing at all we enforce it's
964 * always set instead of having to deal with possibly weird behaviour
965 * for malicious applications setting only __O_SYNC.
966 */
967 if (flags & __O_SYNC)
968 flags |= O_DSYNC;
969
970 if (flags & __O_TMPFILE) {
971 if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
972 return -EINVAL;
973 if (!(acc_mode & MAY_WRITE))
974 return -EINVAL;
975 } else if (flags & O_PATH) {
976 /*
977 * If we have O_PATH in the open flag. Then we
978 * cannot have anything other than the below set of flags
979 */
980 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
981 acc_mode = 0;
982 }
983
984 op->open_flag = flags;
985
986 /* O_TRUNC implies we need access checks for write permissions */
987 if (flags & O_TRUNC)
988 acc_mode |= MAY_WRITE;
989
990 /* Allow the LSM permission hook to distinguish append
991 access from general write access. */
992 if (flags & O_APPEND)
993 acc_mode |= MAY_APPEND;
994
995 op->acc_mode = acc_mode;
996
997 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
998
999 if (flags & O_CREAT) {
1000 op->intent |= LOOKUP_CREATE;
1001 if (flags & O_EXCL)
1002 op->intent |= LOOKUP_EXCL;
1003 }
1004
1005 if (flags & O_DIRECTORY)
1006 lookup_flags |= LOOKUP_DIRECTORY;
1007 if (!(flags & O_NOFOLLOW))
1008 lookup_flags |= LOOKUP_FOLLOW;
1009 op->lookup_flags = lookup_flags;
1010 return 0;
1011}
1012
1013/**
1014 * file_open_name - open file and return file pointer
1015 *
1016 * @name: struct filename containing path to open
1017 * @flags: open flags as per the open(2) second argument
1018 * @mode: mode for the new file if O_CREAT is set, else ignored
1019 *
1020 * This is the helper to open a file from kernelspace if you really
1021 * have to. But in generally you should not do this, so please move
1022 * along, nothing to see here..
1023 */
1024struct file *file_open_name(struct filename *name, int flags, umode_t mode)
1025{
1026 struct open_flags op;
1027 int err = build_open_flags(flags, mode, &op);
1028 return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op);
1029}
1030
1031/**
1032 * filp_open - open file and return file pointer
1033 *
1034 * @filename: path to open
1035 * @flags: open flags as per the open(2) second argument
1036 * @mode: mode for the new file if O_CREAT is set, else ignored
1037 *
1038 * This is the helper to open a file from kernelspace if you really
1039 * have to. But in generally you should not do this, so please move
1040 * along, nothing to see here..
1041 */
1042struct file *filp_open(const char *filename, int flags, umode_t mode)
1043{
1044 struct filename *name = getname_kernel(filename);
1045 struct file *file = ERR_CAST(name);
1046
1047 if (!IS_ERR(name)) {
1048 file = file_open_name(name, flags, mode);
1049 putname(name);
1050 }
1051 return file;
1052}
1053EXPORT_SYMBOL(filp_open);
1054
1055struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
1056 const char *filename, int flags, umode_t mode)
1057{
1058 struct open_flags op;
1059 int err = build_open_flags(flags, mode, &op);
1060 if (err)
1061 return ERR_PTR(err);
1062 return do_file_open_root(dentry, mnt, filename, &op);
1063}
1064EXPORT_SYMBOL(file_open_root);
1065
1066struct file *filp_clone_open(struct file *oldfile)
1067{
1068 struct file *file;
1069 int retval;
1070
1071 file = get_empty_filp();
1072 if (IS_ERR(file))
1073 return file;
1074
1075 file->f_flags = oldfile->f_flags;
1076 retval = vfs_open(&oldfile->f_path, file, oldfile->f_cred);
1077 if (retval) {
1078 put_filp(file);
1079 return ERR_PTR(retval);
1080 }
1081
1082 return file;
1083}
1084EXPORT_SYMBOL(filp_clone_open);
1085
1086long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
1087{
1088 struct open_flags op;
1089 int fd = build_open_flags(flags, mode, &op);
1090 struct filename *tmp;
1091
1092 if (fd)
1093 return fd;
1094
1095 tmp = getname(filename);
1096 if (IS_ERR(tmp))
1097 return PTR_ERR(tmp);
1098
1099 fd = get_unused_fd_flags(flags);
1100 if (fd >= 0) {
1101 struct file *f = do_filp_open(dfd, tmp, &op);
1102 if (IS_ERR(f)) {
1103 put_unused_fd(fd);
1104 fd = PTR_ERR(f);
1105 } else {
1106 fsnotify_open(f);
1107 fd_install(fd, f);
1108 }
1109 }
1110 putname(tmp);
1111 return fd;
1112}
1113
1114SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
1115{
1116 if (force_o_largefile())
1117 flags |= O_LARGEFILE;
1118
1119 return do_sys_open(AT_FDCWD, filename, flags, mode);
1120}
1121
1122SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
1123 umode_t, mode)
1124{
1125 if (force_o_largefile())
1126 flags |= O_LARGEFILE;
1127
1128 return do_sys_open(dfd, filename, flags, mode);
1129}
1130
1131#ifdef CONFIG_COMPAT
1132/*
1133 * Exactly like sys_open(), except that it doesn't set the
1134 * O_LARGEFILE flag.
1135 */
1136COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
1137{
1138 return do_sys_open(AT_FDCWD, filename, flags, mode);
1139}
1140
1141/*
1142 * Exactly like sys_openat(), except that it doesn't set the
1143 * O_LARGEFILE flag.
1144 */
1145COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode)
1146{
1147 return do_sys_open(dfd, filename, flags, mode);
1148}
1149#endif
1150
1151#ifndef __alpha__
1152
1153/*
1154 * For backward compatibility? Maybe this should be moved
1155 * into arch/i386 instead?
1156 */
1157SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
1158{
1159 return ksys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1160}
1161
1162#endif
1163
1164/*
1165 * "id" is the POSIX thread ID. We use the
1166 * files pointer for this..
1167 */
1168int filp_close(struct file *filp, fl_owner_t id)
1169{
1170 int retval = 0;
1171
1172 if (!file_count(filp)) {
1173 printk(KERN_ERR "VFS: Close: file count is 0\n");
1174 return 0;
1175 }
1176
1177 if (filp->f_op->flush)
1178 retval = filp->f_op->flush(filp, id);
1179
1180 if (likely(!(filp->f_mode & FMODE_PATH))) {
1181 dnotify_flush(filp, id);
1182 locks_remove_posix(filp, id);
1183 }
1184 fput(filp);
1185 return retval;
1186}
1187
1188EXPORT_SYMBOL(filp_close);
1189
1190/*
1191 * Careful here! We test whether the file pointer is NULL before
1192 * releasing the fd. This ensures that one clone task can't release
1193 * an fd while another clone is opening it.
1194 */
1195SYSCALL_DEFINE1(close, unsigned int, fd)
1196{
1197 int retval = __close_fd(current->files, fd);
1198
1199 /* can't restart close syscall because file table entry was cleared */
1200 if (unlikely(retval == -ERESTARTSYS ||
1201 retval == -ERESTARTNOINTR ||
1202 retval == -ERESTARTNOHAND ||
1203 retval == -ERESTART_RESTARTBLOCK))
1204 retval = -EINTR;
1205
1206 return retval;
1207}
1208
1209/*
1210 * This routine simulates a hangup on the tty, to arrange that users
1211 * are given clean terminals at login time.
1212 */
1213SYSCALL_DEFINE0(vhangup)
1214{
1215 if (capable(CAP_SYS_TTY_CONFIG)) {
1216 tty_vhangup_self();
1217 return 0;
1218 }
1219 return -EPERM;
1220}
1221
1222/*
1223 * Called when an inode is about to be open.
1224 * We use this to disallow opening large files on 32bit systems if
1225 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1226 * on this flag in sys_open.
1227 */
1228int generic_file_open(struct inode * inode, struct file * filp)
1229{
1230 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1231 return -EOVERFLOW;
1232 return 0;
1233}
1234
1235EXPORT_SYMBOL(generic_file_open);
1236
1237/*
1238 * This is used by subsystems that don't want seekable
1239 * file descriptors. The function is not supposed to ever fail, the only
1240 * reason it returns an 'int' and not 'void' is so that it can be plugged
1241 * directly into file_operations structure.
1242 */
1243int nonseekable_open(struct inode *inode, struct file *filp)
1244{
1245 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1246 return 0;
1247}
1248
1249EXPORT_SYMBOL(nonseekable_open);
1/*
2 * linux/fs/open.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/string.h>
8#include <linux/mm.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>
23#include <linux/fs.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>
34
35#include "internal.h"
36
37int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
38 struct file *filp)
39{
40 int ret;
41 struct iattr newattrs;
42
43 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
44 if (length < 0)
45 return -EINVAL;
46
47 newattrs.ia_size = length;
48 newattrs.ia_valid = ATTR_SIZE | time_attrs;
49 if (filp) {
50 newattrs.ia_file = filp;
51 newattrs.ia_valid |= ATTR_FILE;
52 }
53
54 /* Remove suid/sgid on truncate too */
55 ret = should_remove_suid(dentry);
56 if (ret)
57 newattrs.ia_valid |= ret | ATTR_FORCE;
58
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);
63 return ret;
64}
65
66long vfs_truncate(struct path *path, loff_t length)
67{
68 struct inode *inode;
69 long error;
70
71 inode = path->dentry->d_inode;
72
73 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
74 if (S_ISDIR(inode->i_mode))
75 return -EISDIR;
76 if (!S_ISREG(inode->i_mode))
77 return -EINVAL;
78
79 error = mnt_want_write(path->mnt);
80 if (error)
81 goto out;
82
83 error = inode_permission(inode, MAY_WRITE);
84 if (error)
85 goto mnt_drop_write_and_out;
86
87 error = -EPERM;
88 if (IS_APPEND(inode))
89 goto mnt_drop_write_and_out;
90
91 error = get_write_access(inode);
92 if (error)
93 goto mnt_drop_write_and_out;
94
95 /*
96 * Make sure that there are no leases. get_write_access() protects
97 * against the truncate racing with a lease-granting setlease().
98 */
99 error = break_lease(inode, O_WRONLY);
100 if (error)
101 goto put_write_and_out;
102
103 error = locks_verify_truncate(inode, NULL, length);
104 if (!error)
105 error = security_path_truncate(path);
106 if (!error)
107 error = do_truncate(path->dentry, length, 0, NULL);
108
109put_write_and_out:
110 put_write_access(inode);
111mnt_drop_write_and_out:
112 mnt_drop_write(path->mnt);
113out:
114 return error;
115}
116EXPORT_SYMBOL_GPL(vfs_truncate);
117
118static long do_sys_truncate(const char __user *pathname, loff_t length)
119{
120 unsigned int lookup_flags = LOOKUP_FOLLOW;
121 struct path path;
122 int error;
123
124 if (length < 0) /* sorry, but loff_t says... */
125 return -EINVAL;
126
127retry:
128 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
129 if (!error) {
130 error = vfs_truncate(&path, length);
131 path_put(&path);
132 }
133 if (retry_estale(error, lookup_flags)) {
134 lookup_flags |= LOOKUP_REVAL;
135 goto retry;
136 }
137 return error;
138}
139
140SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
141{
142 return do_sys_truncate(path, length);
143}
144
145#ifdef CONFIG_COMPAT
146COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
147{
148 return do_sys_truncate(path, length);
149}
150#endif
151
152static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
153{
154 struct inode *inode;
155 struct dentry *dentry;
156 struct fd f;
157 int error;
158
159 error = -EINVAL;
160 if (length < 0)
161 goto out;
162 error = -EBADF;
163 f = fdget(fd);
164 if (!f.file)
165 goto out;
166
167 /* explicitly opened as large or we are on 64-bit box */
168 if (f.file->f_flags & O_LARGEFILE)
169 small = 0;
170
171 dentry = f.file->f_path.dentry;
172 inode = dentry->d_inode;
173 error = -EINVAL;
174 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
175 goto out_putf;
176
177 error = -EINVAL;
178 /* Cannot ftruncate over 2^31 bytes without large file support */
179 if (small && length > MAX_NON_LFS)
180 goto out_putf;
181
182 error = -EPERM;
183 if (IS_APPEND(inode))
184 goto out_putf;
185
186 sb_start_write(inode->i_sb);
187 error = locks_verify_truncate(inode, f.file, length);
188 if (!error)
189 error = security_path_truncate(&f.file->f_path);
190 if (!error)
191 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
192 sb_end_write(inode->i_sb);
193out_putf:
194 fdput(f);
195out:
196 return error;
197}
198
199SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
200{
201 return do_sys_ftruncate(fd, length, 1);
202}
203
204#ifdef CONFIG_COMPAT
205COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
206{
207 return do_sys_ftruncate(fd, length, 1);
208}
209#endif
210
211/* LFS versions of truncate are only needed on 32 bit machines */
212#if BITS_PER_LONG == 32
213SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
214{
215 return do_sys_truncate(path, length);
216}
217
218SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
219{
220 return do_sys_ftruncate(fd, length, 0);
221}
222#endif /* BITS_PER_LONG == 32 */
223
224
225int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
226{
227 struct inode *inode = file_inode(file);
228 long ret;
229
230 if (offset < 0 || len <= 0)
231 return -EINVAL;
232
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))
236 return -EOPNOTSUPP;
237
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))
241 return -EOPNOTSUPP;
242
243 /* Punch hole must have keep size set */
244 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
245 !(mode & FALLOC_FL_KEEP_SIZE))
246 return -EOPNOTSUPP;
247
248 /* Collapse range should only be used exclusively. */
249 if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
250 (mode & ~FALLOC_FL_COLLAPSE_RANGE))
251 return -EINVAL;
252
253 if (!(file->f_mode & FMODE_WRITE))
254 return -EBADF;
255
256 /*
257 * We can only allow pure fallocate on append only files
258 */
259 if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
260 return -EPERM;
261
262 if (IS_IMMUTABLE(inode))
263 return -EPERM;
264
265 /*
266 * We can not allow to do any fallocate operation on an active
267 * swapfile
268 */
269 if (IS_SWAPFILE(inode))
270 ret = -ETXTBSY;
271
272 /*
273 * Revalidate the write permissions, in case security policy has
274 * changed since the files were opened.
275 */
276 ret = security_file_permission(file, MAY_WRITE);
277 if (ret)
278 return ret;
279
280 if (S_ISFIFO(inode->i_mode))
281 return -ESPIPE;
282
283 /*
284 * Let individual file system decide if it supports preallocation
285 * for directories or not.
286 */
287 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
288 return -ENODEV;
289
290 /* Check for wrap through zero too */
291 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
292 return -EFBIG;
293
294 if (!file->f_op->fallocate)
295 return -EOPNOTSUPP;
296
297 sb_start_write(inode->i_sb);
298 ret = file->f_op->fallocate(file, mode, offset, len);
299 sb_end_write(inode->i_sb);
300 return ret;
301}
302
303SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
304{
305 struct fd f = fdget(fd);
306 int error = -EBADF;
307
308 if (f.file) {
309 error = do_fallocate(f.file, mode, offset, len);
310 fdput(f);
311 }
312 return error;
313}
314
315/*
316 * access() needs to use the real uid/gid, not the effective uid/gid.
317 * We do this by temporarily clearing all FS-related capabilities and
318 * switching the fsuid/fsgid around to the real ones.
319 */
320SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
321{
322 const struct cred *old_cred;
323 struct cred *override_cred;
324 struct path path;
325 struct inode *inode;
326 int res;
327 unsigned int lookup_flags = LOOKUP_FOLLOW;
328
329 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
330 return -EINVAL;
331
332 override_cred = prepare_creds();
333 if (!override_cred)
334 return -ENOMEM;
335
336 override_cred->fsuid = override_cred->uid;
337 override_cred->fsgid = override_cred->gid;
338
339 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
340 /* Clear the capabilities if we switch to a non-root user */
341 kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
342 if (!uid_eq(override_cred->uid, root_uid))
343 cap_clear(override_cred->cap_effective);
344 else
345 override_cred->cap_effective =
346 override_cred->cap_permitted;
347 }
348
349 old_cred = override_creds(override_cred);
350retry:
351 res = user_path_at(dfd, filename, lookup_flags, &path);
352 if (res)
353 goto out;
354
355 inode = path.dentry->d_inode;
356
357 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
358 /*
359 * MAY_EXEC on regular files is denied if the fs is mounted
360 * with the "noexec" flag.
361 */
362 res = -EACCES;
363 if (path.mnt->mnt_flags & MNT_NOEXEC)
364 goto out_path_release;
365 }
366
367 res = inode_permission(inode, mode | MAY_ACCESS);
368 /* SuS v2 requires we report a read only fs too */
369 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
370 goto out_path_release;
371 /*
372 * This is a rare case where using __mnt_is_readonly()
373 * is OK without a mnt_want/drop_write() pair. Since
374 * no actual write to the fs is performed here, we do
375 * not need to telegraph to that to anyone.
376 *
377 * By doing this, we accept that this access is
378 * inherently racy and know that the fs may change
379 * state before we even see this result.
380 */
381 if (__mnt_is_readonly(path.mnt))
382 res = -EROFS;
383
384out_path_release:
385 path_put(&path);
386 if (retry_estale(res, lookup_flags)) {
387 lookup_flags |= LOOKUP_REVAL;
388 goto retry;
389 }
390out:
391 revert_creds(old_cred);
392 put_cred(override_cred);
393 return res;
394}
395
396SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
397{
398 return sys_faccessat(AT_FDCWD, filename, mode);
399}
400
401SYSCALL_DEFINE1(chdir, const char __user *, filename)
402{
403 struct path path;
404 int error;
405 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
406retry:
407 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
408 if (error)
409 goto out;
410
411 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
412 if (error)
413 goto dput_and_out;
414
415 set_fs_pwd(current->fs, &path);
416
417dput_and_out:
418 path_put(&path);
419 if (retry_estale(error, lookup_flags)) {
420 lookup_flags |= LOOKUP_REVAL;
421 goto retry;
422 }
423out:
424 return error;
425}
426
427SYSCALL_DEFINE1(fchdir, unsigned int, fd)
428{
429 struct fd f = fdget_raw(fd);
430 struct inode *inode;
431 int error = -EBADF;
432
433 error = -EBADF;
434 if (!f.file)
435 goto out;
436
437 inode = file_inode(f.file);
438
439 error = -ENOTDIR;
440 if (!S_ISDIR(inode->i_mode))
441 goto out_putf;
442
443 error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
444 if (!error)
445 set_fs_pwd(current->fs, &f.file->f_path);
446out_putf:
447 fdput(f);
448out:
449 return error;
450}
451
452SYSCALL_DEFINE1(chroot, const char __user *, filename)
453{
454 struct path path;
455 int error;
456 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
457retry:
458 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
459 if (error)
460 goto out;
461
462 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
463 if (error)
464 goto dput_and_out;
465
466 error = -EPERM;
467 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
468 goto dput_and_out;
469 error = security_path_chroot(&path);
470 if (error)
471 goto dput_and_out;
472
473 set_fs_root(current->fs, &path);
474 error = 0;
475dput_and_out:
476 path_put(&path);
477 if (retry_estale(error, lookup_flags)) {
478 lookup_flags |= LOOKUP_REVAL;
479 goto retry;
480 }
481out:
482 return error;
483}
484
485static int chmod_common(struct path *path, umode_t mode)
486{
487 struct inode *inode = path->dentry->d_inode;
488 struct inode *delegated_inode = NULL;
489 struct iattr newattrs;
490 int error;
491
492 error = mnt_want_write(path->mnt);
493 if (error)
494 return error;
495retry_deleg:
496 mutex_lock(&inode->i_mutex);
497 error = security_path_chmod(path, mode);
498 if (error)
499 goto out_unlock;
500 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
501 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
502 error = notify_change(path->dentry, &newattrs, &delegated_inode);
503out_unlock:
504 mutex_unlock(&inode->i_mutex);
505 if (delegated_inode) {
506 error = break_deleg_wait(&delegated_inode);
507 if (!error)
508 goto retry_deleg;
509 }
510 mnt_drop_write(path->mnt);
511 return error;
512}
513
514SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
515{
516 struct fd f = fdget(fd);
517 int err = -EBADF;
518
519 if (f.file) {
520 audit_inode(NULL, f.file->f_path.dentry, 0);
521 err = chmod_common(&f.file->f_path, mode);
522 fdput(f);
523 }
524 return err;
525}
526
527SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
528{
529 struct path path;
530 int error;
531 unsigned int lookup_flags = LOOKUP_FOLLOW;
532retry:
533 error = user_path_at(dfd, filename, lookup_flags, &path);
534 if (!error) {
535 error = chmod_common(&path, mode);
536 path_put(&path);
537 if (retry_estale(error, lookup_flags)) {
538 lookup_flags |= LOOKUP_REVAL;
539 goto retry;
540 }
541 }
542 return error;
543}
544
545SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
546{
547 return sys_fchmodat(AT_FDCWD, filename, mode);
548}
549
550static int chown_common(struct path *path, uid_t user, gid_t group)
551{
552 struct inode *inode = path->dentry->d_inode;
553 struct inode *delegated_inode = NULL;
554 int error;
555 struct iattr newattrs;
556 kuid_t uid;
557 kgid_t gid;
558
559 uid = make_kuid(current_user_ns(), user);
560 gid = make_kgid(current_user_ns(), group);
561
562 newattrs.ia_valid = ATTR_CTIME;
563 if (user != (uid_t) -1) {
564 if (!uid_valid(uid))
565 return -EINVAL;
566 newattrs.ia_valid |= ATTR_UID;
567 newattrs.ia_uid = uid;
568 }
569 if (group != (gid_t) -1) {
570 if (!gid_valid(gid))
571 return -EINVAL;
572 newattrs.ia_valid |= ATTR_GID;
573 newattrs.ia_gid = gid;
574 }
575 if (!S_ISDIR(inode->i_mode))
576 newattrs.ia_valid |=
577 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
578retry_deleg:
579 mutex_lock(&inode->i_mutex);
580 error = security_path_chown(path, uid, gid);
581 if (!error)
582 error = notify_change(path->dentry, &newattrs, &delegated_inode);
583 mutex_unlock(&inode->i_mutex);
584 if (delegated_inode) {
585 error = break_deleg_wait(&delegated_inode);
586 if (!error)
587 goto retry_deleg;
588 }
589 return error;
590}
591
592SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
593 gid_t, group, int, flag)
594{
595 struct path path;
596 int error = -EINVAL;
597 int lookup_flags;
598
599 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
600 goto out;
601
602 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
603 if (flag & AT_EMPTY_PATH)
604 lookup_flags |= LOOKUP_EMPTY;
605retry:
606 error = user_path_at(dfd, filename, lookup_flags, &path);
607 if (error)
608 goto out;
609 error = mnt_want_write(path.mnt);
610 if (error)
611 goto out_release;
612 error = chown_common(&path, user, group);
613 mnt_drop_write(path.mnt);
614out_release:
615 path_put(&path);
616 if (retry_estale(error, lookup_flags)) {
617 lookup_flags |= LOOKUP_REVAL;
618 goto retry;
619 }
620out:
621 return error;
622}
623
624SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
625{
626 return sys_fchownat(AT_FDCWD, filename, user, group, 0);
627}
628
629SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
630{
631 return sys_fchownat(AT_FDCWD, filename, user, group,
632 AT_SYMLINK_NOFOLLOW);
633}
634
635SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
636{
637 struct fd f = fdget(fd);
638 int error = -EBADF;
639
640 if (!f.file)
641 goto out;
642
643 error = mnt_want_write_file(f.file);
644 if (error)
645 goto out_fput;
646 audit_inode(NULL, f.file->f_path.dentry, 0);
647 error = chown_common(&f.file->f_path, user, group);
648 mnt_drop_write_file(f.file);
649out_fput:
650 fdput(f);
651out:
652 return error;
653}
654
655int open_check_o_direct(struct file *f)
656{
657 /* NB: we're sure to have correct a_ops only after f_op->open */
658 if (f->f_flags & O_DIRECT) {
659 if (!f->f_mapping->a_ops ||
660 ((!f->f_mapping->a_ops->direct_IO) &&
661 (!f->f_mapping->a_ops->get_xip_mem))) {
662 return -EINVAL;
663 }
664 }
665 return 0;
666}
667
668static int do_dentry_open(struct file *f,
669 int (*open)(struct inode *, struct file *),
670 const struct cred *cred)
671{
672 static const struct file_operations empty_fops = {};
673 struct inode *inode;
674 int error;
675
676 f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
677 FMODE_PREAD | FMODE_PWRITE;
678
679 path_get(&f->f_path);
680 inode = f->f_inode = f->f_path.dentry->d_inode;
681 f->f_mapping = inode->i_mapping;
682
683 if (unlikely(f->f_flags & O_PATH)) {
684 f->f_mode = FMODE_PATH;
685 f->f_op = &empty_fops;
686 return 0;
687 }
688
689 if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
690 error = get_write_access(inode);
691 if (unlikely(error))
692 goto cleanup_file;
693 error = __mnt_want_write(f->f_path.mnt);
694 if (unlikely(error)) {
695 put_write_access(inode);
696 goto cleanup_file;
697 }
698 f->f_mode |= FMODE_WRITER;
699 }
700
701 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
702 if (S_ISREG(inode->i_mode))
703 f->f_mode |= FMODE_ATOMIC_POS;
704
705 f->f_op = fops_get(inode->i_fop);
706 if (unlikely(WARN_ON(!f->f_op))) {
707 error = -ENODEV;
708 goto cleanup_all;
709 }
710
711 error = security_file_open(f, cred);
712 if (error)
713 goto cleanup_all;
714
715 error = break_lease(inode, f->f_flags);
716 if (error)
717 goto cleanup_all;
718
719 if (!open)
720 open = f->f_op->open;
721 if (open) {
722 error = open(inode, f);
723 if (error)
724 goto cleanup_all;
725 }
726 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
727 i_readcount_inc(inode);
728
729 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
730
731 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
732
733 return 0;
734
735cleanup_all:
736 fops_put(f->f_op);
737 if (f->f_mode & FMODE_WRITER) {
738 put_write_access(inode);
739 __mnt_drop_write(f->f_path.mnt);
740 }
741cleanup_file:
742 path_put(&f->f_path);
743 f->f_path.mnt = NULL;
744 f->f_path.dentry = NULL;
745 f->f_inode = NULL;
746 return error;
747}
748
749/**
750 * finish_open - finish opening a file
751 * @file: file pointer
752 * @dentry: pointer to dentry
753 * @open: open callback
754 * @opened: state of open
755 *
756 * This can be used to finish opening a file passed to i_op->atomic_open().
757 *
758 * If the open callback is set to NULL, then the standard f_op->open()
759 * filesystem callback is substituted.
760 *
761 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
762 * the return value of d_splice_alias(), then the caller needs to perform dput()
763 * on it after finish_open().
764 *
765 * On successful return @file is a fully instantiated open file. After this, if
766 * an error occurs in ->atomic_open(), it needs to clean up with fput().
767 *
768 * Returns zero on success or -errno if the open failed.
769 */
770int finish_open(struct file *file, struct dentry *dentry,
771 int (*open)(struct inode *, struct file *),
772 int *opened)
773{
774 int error;
775 BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
776
777 file->f_path.dentry = dentry;
778 error = do_dentry_open(file, open, current_cred());
779 if (!error)
780 *opened |= FILE_OPENED;
781
782 return error;
783}
784EXPORT_SYMBOL(finish_open);
785
786/**
787 * finish_no_open - finish ->atomic_open() without opening the file
788 *
789 * @file: file pointer
790 * @dentry: dentry or NULL (as returned from ->lookup())
791 *
792 * This can be used to set the result of a successful lookup in ->atomic_open().
793 *
794 * NB: unlike finish_open() this function does consume the dentry reference and
795 * the caller need not dput() it.
796 *
797 * Returns "1" which must be the return value of ->atomic_open() after having
798 * called this function.
799 */
800int finish_no_open(struct file *file, struct dentry *dentry)
801{
802 file->f_path.dentry = dentry;
803 return 1;
804}
805EXPORT_SYMBOL(finish_no_open);
806
807struct file *dentry_open(const struct path *path, int flags,
808 const struct cred *cred)
809{
810 int error;
811 struct file *f;
812
813 validate_creds(cred);
814
815 /* We must always pass in a valid mount pointer. */
816 BUG_ON(!path->mnt);
817
818 f = get_empty_filp();
819 if (!IS_ERR(f)) {
820 f->f_flags = flags;
821 f->f_path = *path;
822 error = do_dentry_open(f, NULL, cred);
823 if (!error) {
824 /* from now on we need fput() to dispose of f */
825 error = open_check_o_direct(f);
826 if (error) {
827 fput(f);
828 f = ERR_PTR(error);
829 }
830 } else {
831 put_filp(f);
832 f = ERR_PTR(error);
833 }
834 }
835 return f;
836}
837EXPORT_SYMBOL(dentry_open);
838
839static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
840{
841 int lookup_flags = 0;
842 int acc_mode;
843
844 if (flags & (O_CREAT | __O_TMPFILE))
845 op->mode = (mode & S_IALLUGO) | S_IFREG;
846 else
847 op->mode = 0;
848
849 /* Must never be set by userspace */
850 flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
851
852 /*
853 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
854 * check for O_DSYNC if the need any syncing at all we enforce it's
855 * always set instead of having to deal with possibly weird behaviour
856 * for malicious applications setting only __O_SYNC.
857 */
858 if (flags & __O_SYNC)
859 flags |= O_DSYNC;
860
861 if (flags & __O_TMPFILE) {
862 if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
863 return -EINVAL;
864 acc_mode = MAY_OPEN | ACC_MODE(flags);
865 if (!(acc_mode & MAY_WRITE))
866 return -EINVAL;
867 } else if (flags & O_PATH) {
868 /*
869 * If we have O_PATH in the open flag. Then we
870 * cannot have anything other than the below set of flags
871 */
872 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
873 acc_mode = 0;
874 } else {
875 acc_mode = MAY_OPEN | ACC_MODE(flags);
876 }
877
878 op->open_flag = flags;
879
880 /* O_TRUNC implies we need access checks for write permissions */
881 if (flags & O_TRUNC)
882 acc_mode |= MAY_WRITE;
883
884 /* Allow the LSM permission hook to distinguish append
885 access from general write access. */
886 if (flags & O_APPEND)
887 acc_mode |= MAY_APPEND;
888
889 op->acc_mode = acc_mode;
890
891 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
892
893 if (flags & O_CREAT) {
894 op->intent |= LOOKUP_CREATE;
895 if (flags & O_EXCL)
896 op->intent |= LOOKUP_EXCL;
897 }
898
899 if (flags & O_DIRECTORY)
900 lookup_flags |= LOOKUP_DIRECTORY;
901 if (!(flags & O_NOFOLLOW))
902 lookup_flags |= LOOKUP_FOLLOW;
903 op->lookup_flags = lookup_flags;
904 return 0;
905}
906
907/**
908 * file_open_name - open file and return file pointer
909 *
910 * @name: struct filename containing path to open
911 * @flags: open flags as per the open(2) second argument
912 * @mode: mode for the new file if O_CREAT is set, else ignored
913 *
914 * This is the helper to open a file from kernelspace if you really
915 * have to. But in generally you should not do this, so please move
916 * along, nothing to see here..
917 */
918struct file *file_open_name(struct filename *name, int flags, umode_t mode)
919{
920 struct open_flags op;
921 int err = build_open_flags(flags, mode, &op);
922 return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op);
923}
924
925/**
926 * filp_open - open file and return file pointer
927 *
928 * @filename: path to open
929 * @flags: open flags as per the open(2) second argument
930 * @mode: mode for the new file if O_CREAT is set, else ignored
931 *
932 * This is the helper to open a file from kernelspace if you really
933 * have to. But in generally you should not do this, so please move
934 * along, nothing to see here..
935 */
936struct file *filp_open(const char *filename, int flags, umode_t mode)
937{
938 struct filename name = {.name = filename};
939 return file_open_name(&name, flags, mode);
940}
941EXPORT_SYMBOL(filp_open);
942
943struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
944 const char *filename, int flags)
945{
946 struct open_flags op;
947 int err = build_open_flags(flags, 0, &op);
948 if (err)
949 return ERR_PTR(err);
950 if (flags & O_CREAT)
951 return ERR_PTR(-EINVAL);
952 if (!filename && (flags & O_DIRECTORY))
953 if (!dentry->d_inode->i_op->lookup)
954 return ERR_PTR(-ENOTDIR);
955 return do_file_open_root(dentry, mnt, filename, &op);
956}
957EXPORT_SYMBOL(file_open_root);
958
959long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
960{
961 struct open_flags op;
962 int fd = build_open_flags(flags, mode, &op);
963 struct filename *tmp;
964
965 if (fd)
966 return fd;
967
968 tmp = getname(filename);
969 if (IS_ERR(tmp))
970 return PTR_ERR(tmp);
971
972 fd = get_unused_fd_flags(flags);
973 if (fd >= 0) {
974 struct file *f = do_filp_open(dfd, tmp, &op);
975 if (IS_ERR(f)) {
976 put_unused_fd(fd);
977 fd = PTR_ERR(f);
978 } else {
979 fsnotify_open(f);
980 fd_install(fd, f);
981 }
982 }
983 putname(tmp);
984 return fd;
985}
986
987SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
988{
989 if (force_o_largefile())
990 flags |= O_LARGEFILE;
991
992 return do_sys_open(AT_FDCWD, filename, flags, mode);
993}
994
995SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
996 umode_t, mode)
997{
998 if (force_o_largefile())
999 flags |= O_LARGEFILE;
1000
1001 return do_sys_open(dfd, filename, flags, mode);
1002}
1003
1004#ifndef __alpha__
1005
1006/*
1007 * For backward compatibility? Maybe this should be moved
1008 * into arch/i386 instead?
1009 */
1010SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
1011{
1012 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1013}
1014
1015#endif
1016
1017/*
1018 * "id" is the POSIX thread ID. We use the
1019 * files pointer for this..
1020 */
1021int filp_close(struct file *filp, fl_owner_t id)
1022{
1023 int retval = 0;
1024
1025 if (!file_count(filp)) {
1026 printk(KERN_ERR "VFS: Close: file count is 0\n");
1027 return 0;
1028 }
1029
1030 if (filp->f_op->flush)
1031 retval = filp->f_op->flush(filp, id);
1032
1033 if (likely(!(filp->f_mode & FMODE_PATH))) {
1034 dnotify_flush(filp, id);
1035 locks_remove_posix(filp, id);
1036 }
1037 fput(filp);
1038 return retval;
1039}
1040
1041EXPORT_SYMBOL(filp_close);
1042
1043/*
1044 * Careful here! We test whether the file pointer is NULL before
1045 * releasing the fd. This ensures that one clone task can't release
1046 * an fd while another clone is opening it.
1047 */
1048SYSCALL_DEFINE1(close, unsigned int, fd)
1049{
1050 int retval = __close_fd(current->files, fd);
1051
1052 /* can't restart close syscall because file table entry was cleared */
1053 if (unlikely(retval == -ERESTARTSYS ||
1054 retval == -ERESTARTNOINTR ||
1055 retval == -ERESTARTNOHAND ||
1056 retval == -ERESTART_RESTARTBLOCK))
1057 retval = -EINTR;
1058
1059 return retval;
1060}
1061EXPORT_SYMBOL(sys_close);
1062
1063/*
1064 * This routine simulates a hangup on the tty, to arrange that users
1065 * are given clean terminals at login time.
1066 */
1067SYSCALL_DEFINE0(vhangup)
1068{
1069 if (capable(CAP_SYS_TTY_CONFIG)) {
1070 tty_vhangup_self();
1071 return 0;
1072 }
1073 return -EPERM;
1074}
1075
1076/*
1077 * Called when an inode is about to be open.
1078 * We use this to disallow opening large files on 32bit systems if
1079 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1080 * on this flag in sys_open.
1081 */
1082int generic_file_open(struct inode * inode, struct file * filp)
1083{
1084 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1085 return -EOVERFLOW;
1086 return 0;
1087}
1088
1089EXPORT_SYMBOL(generic_file_open);
1090
1091/*
1092 * This is used by subsystems that don't want seekable
1093 * file descriptors. The function is not supposed to ever fail, the only
1094 * reason it returns an 'int' and not 'void' is so that it can be plugged
1095 * directly into file_operations structure.
1096 */
1097int nonseekable_open(struct inode *inode, struct file *filp)
1098{
1099 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1100 return 0;
1101}
1102
1103EXPORT_SYMBOL(nonseekable_open);