ocfs2: Enable metadata checksums.
[deliverable/linux.git] / fs / open.c
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/quotaops.h>
12 #include <linux/fsnotify.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/tty.h>
16 #include <linux/namei.h>
17 #include <linux/backing-dev.h>
18 #include <linux/capability.h>
19 #include <linux/securebits.h>
20 #include <linux/security.h>
21 #include <linux/mount.h>
22 #include <linux/vfs.h>
23 #include <linux/fcntl.h>
24 #include <asm/uaccess.h>
25 #include <linux/fs.h>
26 #include <linux/personality.h>
27 #include <linux/pagemap.h>
28 #include <linux/syscalls.h>
29 #include <linux/rcupdate.h>
30 #include <linux/audit.h>
31 #include <linux/falloc.h>
32
33 int vfs_statfs(struct dentry *dentry, struct kstatfs *buf)
34 {
35 int retval = -ENODEV;
36
37 if (dentry) {
38 retval = -ENOSYS;
39 if (dentry->d_sb->s_op->statfs) {
40 memset(buf, 0, sizeof(*buf));
41 retval = security_sb_statfs(dentry);
42 if (retval)
43 return retval;
44 retval = dentry->d_sb->s_op->statfs(dentry, buf);
45 if (retval == 0 && buf->f_frsize == 0)
46 buf->f_frsize = buf->f_bsize;
47 }
48 }
49 return retval;
50 }
51
52 EXPORT_SYMBOL(vfs_statfs);
53
54 static int vfs_statfs_native(struct dentry *dentry, struct statfs *buf)
55 {
56 struct kstatfs st;
57 int retval;
58
59 retval = vfs_statfs(dentry, &st);
60 if (retval)
61 return retval;
62
63 if (sizeof(*buf) == sizeof(st))
64 memcpy(buf, &st, sizeof(st));
65 else {
66 if (sizeof buf->f_blocks == 4) {
67 if ((st.f_blocks | st.f_bfree | st.f_bavail |
68 st.f_bsize | st.f_frsize) &
69 0xffffffff00000000ULL)
70 return -EOVERFLOW;
71 /*
72 * f_files and f_ffree may be -1; it's okay to stuff
73 * that into 32 bits
74 */
75 if (st.f_files != -1 &&
76 (st.f_files & 0xffffffff00000000ULL))
77 return -EOVERFLOW;
78 if (st.f_ffree != -1 &&
79 (st.f_ffree & 0xffffffff00000000ULL))
80 return -EOVERFLOW;
81 }
82
83 buf->f_type = st.f_type;
84 buf->f_bsize = st.f_bsize;
85 buf->f_blocks = st.f_blocks;
86 buf->f_bfree = st.f_bfree;
87 buf->f_bavail = st.f_bavail;
88 buf->f_files = st.f_files;
89 buf->f_ffree = st.f_ffree;
90 buf->f_fsid = st.f_fsid;
91 buf->f_namelen = st.f_namelen;
92 buf->f_frsize = st.f_frsize;
93 memset(buf->f_spare, 0, sizeof(buf->f_spare));
94 }
95 return 0;
96 }
97
98 static int vfs_statfs64(struct dentry *dentry, struct statfs64 *buf)
99 {
100 struct kstatfs st;
101 int retval;
102
103 retval = vfs_statfs(dentry, &st);
104 if (retval)
105 return retval;
106
107 if (sizeof(*buf) == sizeof(st))
108 memcpy(buf, &st, sizeof(st));
109 else {
110 buf->f_type = st.f_type;
111 buf->f_bsize = st.f_bsize;
112 buf->f_blocks = st.f_blocks;
113 buf->f_bfree = st.f_bfree;
114 buf->f_bavail = st.f_bavail;
115 buf->f_files = st.f_files;
116 buf->f_ffree = st.f_ffree;
117 buf->f_fsid = st.f_fsid;
118 buf->f_namelen = st.f_namelen;
119 buf->f_frsize = st.f_frsize;
120 memset(buf->f_spare, 0, sizeof(buf->f_spare));
121 }
122 return 0;
123 }
124
125 asmlinkage long sys_statfs(const char __user *pathname, struct statfs __user * buf)
126 {
127 struct path path;
128 int error;
129
130 error = user_path(pathname, &path);
131 if (!error) {
132 struct statfs tmp;
133 error = vfs_statfs_native(path.dentry, &tmp);
134 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
135 error = -EFAULT;
136 path_put(&path);
137 }
138 return error;
139 }
140
141
142 asmlinkage long sys_statfs64(const char __user *pathname, size_t sz, struct statfs64 __user *buf)
143 {
144 struct path path;
145 long error;
146
147 if (sz != sizeof(*buf))
148 return -EINVAL;
149 error = user_path(pathname, &path);
150 if (!error) {
151 struct statfs64 tmp;
152 error = vfs_statfs64(path.dentry, &tmp);
153 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
154 error = -EFAULT;
155 path_put(&path);
156 }
157 return error;
158 }
159
160
161 asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf)
162 {
163 struct file * file;
164 struct statfs tmp;
165 int error;
166
167 error = -EBADF;
168 file = fget(fd);
169 if (!file)
170 goto out;
171 error = vfs_statfs_native(file->f_path.dentry, &tmp);
172 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
173 error = -EFAULT;
174 fput(file);
175 out:
176 return error;
177 }
178
179 asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf)
180 {
181 struct file * file;
182 struct statfs64 tmp;
183 int error;
184
185 if (sz != sizeof(*buf))
186 return -EINVAL;
187
188 error = -EBADF;
189 file = fget(fd);
190 if (!file)
191 goto out;
192 error = vfs_statfs64(file->f_path.dentry, &tmp);
193 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
194 error = -EFAULT;
195 fput(file);
196 out:
197 return error;
198 }
199
200 int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
201 struct file *filp)
202 {
203 int err;
204 struct iattr newattrs;
205
206 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
207 if (length < 0)
208 return -EINVAL;
209
210 newattrs.ia_size = length;
211 newattrs.ia_valid = ATTR_SIZE | time_attrs;
212 if (filp) {
213 newattrs.ia_file = filp;
214 newattrs.ia_valid |= ATTR_FILE;
215 }
216
217 /* Remove suid/sgid on truncate too */
218 newattrs.ia_valid |= should_remove_suid(dentry);
219
220 mutex_lock(&dentry->d_inode->i_mutex);
221 err = notify_change(dentry, &newattrs);
222 mutex_unlock(&dentry->d_inode->i_mutex);
223 return err;
224 }
225
226 static long do_sys_truncate(const char __user *pathname, loff_t length)
227 {
228 struct path path;
229 struct inode *inode;
230 int error;
231
232 error = -EINVAL;
233 if (length < 0) /* sorry, but loff_t says... */
234 goto out;
235
236 error = user_path(pathname, &path);
237 if (error)
238 goto out;
239 inode = path.dentry->d_inode;
240
241 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
242 error = -EISDIR;
243 if (S_ISDIR(inode->i_mode))
244 goto dput_and_out;
245
246 error = -EINVAL;
247 if (!S_ISREG(inode->i_mode))
248 goto dput_and_out;
249
250 error = mnt_want_write(path.mnt);
251 if (error)
252 goto dput_and_out;
253
254 error = inode_permission(inode, MAY_WRITE);
255 if (error)
256 goto mnt_drop_write_and_out;
257
258 error = -EPERM;
259 if (IS_APPEND(inode))
260 goto mnt_drop_write_and_out;
261
262 error = get_write_access(inode);
263 if (error)
264 goto mnt_drop_write_and_out;
265
266 /*
267 * Make sure that there are no leases. get_write_access() protects
268 * against the truncate racing with a lease-granting setlease().
269 */
270 error = break_lease(inode, FMODE_WRITE);
271 if (error)
272 goto put_write_and_out;
273
274 error = locks_verify_truncate(inode, NULL, length);
275 if (!error)
276 error = security_path_truncate(&path, length, 0);
277 if (!error) {
278 DQUOT_INIT(inode);
279 error = do_truncate(path.dentry, length, 0, NULL);
280 }
281
282 put_write_and_out:
283 put_write_access(inode);
284 mnt_drop_write_and_out:
285 mnt_drop_write(path.mnt);
286 dput_and_out:
287 path_put(&path);
288 out:
289 return error;
290 }
291
292 asmlinkage long sys_truncate(const char __user * path, unsigned long length)
293 {
294 /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
295 return do_sys_truncate(path, (long)length);
296 }
297
298 static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
299 {
300 struct inode * inode;
301 struct dentry *dentry;
302 struct file * file;
303 int error;
304
305 error = -EINVAL;
306 if (length < 0)
307 goto out;
308 error = -EBADF;
309 file = fget(fd);
310 if (!file)
311 goto out;
312
313 /* explicitly opened as large or we are on 64-bit box */
314 if (file->f_flags & O_LARGEFILE)
315 small = 0;
316
317 dentry = file->f_path.dentry;
318 inode = dentry->d_inode;
319 error = -EINVAL;
320 if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
321 goto out_putf;
322
323 error = -EINVAL;
324 /* Cannot ftruncate over 2^31 bytes without large file support */
325 if (small && length > MAX_NON_LFS)
326 goto out_putf;
327
328 error = -EPERM;
329 if (IS_APPEND(inode))
330 goto out_putf;
331
332 error = locks_verify_truncate(inode, file, length);
333 if (!error)
334 error = security_path_truncate(&file->f_path, length,
335 ATTR_MTIME|ATTR_CTIME);
336 if (!error)
337 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file);
338 out_putf:
339 fput(file);
340 out:
341 return error;
342 }
343
344 asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
345 {
346 long ret = do_sys_ftruncate(fd, length, 1);
347 /* avoid REGPARM breakage on x86: */
348 asmlinkage_protect(2, ret, fd, length);
349 return ret;
350 }
351
352 /* LFS versions of truncate are only needed on 32 bit machines */
353 #if BITS_PER_LONG == 32
354 asmlinkage long sys_truncate64(const char __user * path, loff_t length)
355 {
356 return do_sys_truncate(path, length);
357 }
358
359 asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
360 {
361 long ret = do_sys_ftruncate(fd, length, 0);
362 /* avoid REGPARM breakage on x86: */
363 asmlinkage_protect(2, ret, fd, length);
364 return ret;
365 }
366 #endif
367
368 asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len)
369 {
370 struct file *file;
371 struct inode *inode;
372 long ret = -EINVAL;
373
374 if (offset < 0 || len <= 0)
375 goto out;
376
377 /* Return error if mode is not supported */
378 ret = -EOPNOTSUPP;
379 if (mode && !(mode & FALLOC_FL_KEEP_SIZE))
380 goto out;
381
382 ret = -EBADF;
383 file = fget(fd);
384 if (!file)
385 goto out;
386 if (!(file->f_mode & FMODE_WRITE))
387 goto out_fput;
388 /*
389 * Revalidate the write permissions, in case security policy has
390 * changed since the files were opened.
391 */
392 ret = security_file_permission(file, MAY_WRITE);
393 if (ret)
394 goto out_fput;
395
396 inode = file->f_path.dentry->d_inode;
397
398 ret = -ESPIPE;
399 if (S_ISFIFO(inode->i_mode))
400 goto out_fput;
401
402 ret = -ENODEV;
403 /*
404 * Let individual file system decide if it supports preallocation
405 * for directories or not.
406 */
407 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
408 goto out_fput;
409
410 ret = -EFBIG;
411 /* Check for wrap through zero too */
412 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
413 goto out_fput;
414
415 if (inode->i_op && inode->i_op->fallocate)
416 ret = inode->i_op->fallocate(inode, mode, offset, len);
417 else
418 ret = -EOPNOTSUPP;
419
420 out_fput:
421 fput(file);
422 out:
423 return ret;
424 }
425
426 /*
427 * access() needs to use the real uid/gid, not the effective uid/gid.
428 * We do this by temporarily clearing all FS-related capabilities and
429 * switching the fsuid/fsgid around to the real ones.
430 */
431 asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode)
432 {
433 const struct cred *old_cred;
434 struct cred *override_cred;
435 struct path path;
436 struct inode *inode;
437 int res;
438
439 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
440 return -EINVAL;
441
442 override_cred = prepare_creds();
443 if (!override_cred)
444 return -ENOMEM;
445
446 override_cred->fsuid = override_cred->uid;
447 override_cred->fsgid = override_cred->gid;
448
449 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
450 /* Clear the capabilities if we switch to a non-root user */
451 if (override_cred->uid)
452 cap_clear(override_cred->cap_effective);
453 else
454 override_cred->cap_effective =
455 override_cred->cap_permitted;
456 }
457
458 old_cred = override_creds(override_cred);
459
460 res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
461 if (res)
462 goto out;
463
464 inode = path.dentry->d_inode;
465
466 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
467 /*
468 * MAY_EXEC on regular files is denied if the fs is mounted
469 * with the "noexec" flag.
470 */
471 res = -EACCES;
472 if (path.mnt->mnt_flags & MNT_NOEXEC)
473 goto out_path_release;
474 }
475
476 res = inode_permission(inode, mode | MAY_ACCESS);
477 /* SuS v2 requires we report a read only fs too */
478 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
479 goto out_path_release;
480 /*
481 * This is a rare case where using __mnt_is_readonly()
482 * is OK without a mnt_want/drop_write() pair. Since
483 * no actual write to the fs is performed here, we do
484 * not need to telegraph to that to anyone.
485 *
486 * By doing this, we accept that this access is
487 * inherently racy and know that the fs may change
488 * state before we even see this result.
489 */
490 if (__mnt_is_readonly(path.mnt))
491 res = -EROFS;
492
493 out_path_release:
494 path_put(&path);
495 out:
496 revert_creds(old_cred);
497 put_cred(override_cred);
498 return res;
499 }
500
501 asmlinkage long sys_access(const char __user *filename, int mode)
502 {
503 return sys_faccessat(AT_FDCWD, filename, mode);
504 }
505
506 asmlinkage long sys_chdir(const char __user * filename)
507 {
508 struct path path;
509 int error;
510
511 error = user_path_dir(filename, &path);
512 if (error)
513 goto out;
514
515 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
516 if (error)
517 goto dput_and_out;
518
519 set_fs_pwd(current->fs, &path);
520
521 dput_and_out:
522 path_put(&path);
523 out:
524 return error;
525 }
526
527 asmlinkage long sys_fchdir(unsigned int fd)
528 {
529 struct file *file;
530 struct inode *inode;
531 int error;
532
533 error = -EBADF;
534 file = fget(fd);
535 if (!file)
536 goto out;
537
538 inode = file->f_path.dentry->d_inode;
539
540 error = -ENOTDIR;
541 if (!S_ISDIR(inode->i_mode))
542 goto out_putf;
543
544 error = inode_permission(inode, MAY_EXEC | MAY_ACCESS);
545 if (!error)
546 set_fs_pwd(current->fs, &file->f_path);
547 out_putf:
548 fput(file);
549 out:
550 return error;
551 }
552
553 asmlinkage long sys_chroot(const char __user * filename)
554 {
555 struct path path;
556 int error;
557
558 error = user_path_dir(filename, &path);
559 if (error)
560 goto out;
561
562 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
563 if (error)
564 goto dput_and_out;
565
566 error = -EPERM;
567 if (!capable(CAP_SYS_CHROOT))
568 goto dput_and_out;
569
570 set_fs_root(current->fs, &path);
571 error = 0;
572 dput_and_out:
573 path_put(&path);
574 out:
575 return error;
576 }
577
578 asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
579 {
580 struct inode * inode;
581 struct dentry * dentry;
582 struct file * file;
583 int err = -EBADF;
584 struct iattr newattrs;
585
586 file = fget(fd);
587 if (!file)
588 goto out;
589
590 dentry = file->f_path.dentry;
591 inode = dentry->d_inode;
592
593 audit_inode(NULL, dentry);
594
595 err = mnt_want_write(file->f_path.mnt);
596 if (err)
597 goto out_putf;
598 mutex_lock(&inode->i_mutex);
599 if (mode == (mode_t) -1)
600 mode = inode->i_mode;
601 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
602 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
603 err = notify_change(dentry, &newattrs);
604 mutex_unlock(&inode->i_mutex);
605 mnt_drop_write(file->f_path.mnt);
606 out_putf:
607 fput(file);
608 out:
609 return err;
610 }
611
612 asmlinkage long sys_fchmodat(int dfd, const char __user *filename,
613 mode_t mode)
614 {
615 struct path path;
616 struct inode *inode;
617 int error;
618 struct iattr newattrs;
619
620 error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
621 if (error)
622 goto out;
623 inode = path.dentry->d_inode;
624
625 error = mnt_want_write(path.mnt);
626 if (error)
627 goto dput_and_out;
628 mutex_lock(&inode->i_mutex);
629 if (mode == (mode_t) -1)
630 mode = inode->i_mode;
631 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
632 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
633 error = notify_change(path.dentry, &newattrs);
634 mutex_unlock(&inode->i_mutex);
635 mnt_drop_write(path.mnt);
636 dput_and_out:
637 path_put(&path);
638 out:
639 return error;
640 }
641
642 asmlinkage long sys_chmod(const char __user *filename, mode_t mode)
643 {
644 return sys_fchmodat(AT_FDCWD, filename, mode);
645 }
646
647 static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
648 {
649 struct inode *inode = dentry->d_inode;
650 int error;
651 struct iattr newattrs;
652
653 newattrs.ia_valid = ATTR_CTIME;
654 if (user != (uid_t) -1) {
655 newattrs.ia_valid |= ATTR_UID;
656 newattrs.ia_uid = user;
657 }
658 if (group != (gid_t) -1) {
659 newattrs.ia_valid |= ATTR_GID;
660 newattrs.ia_gid = group;
661 }
662 if (!S_ISDIR(inode->i_mode))
663 newattrs.ia_valid |=
664 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
665 mutex_lock(&inode->i_mutex);
666 error = notify_change(dentry, &newattrs);
667 mutex_unlock(&inode->i_mutex);
668
669 return error;
670 }
671
672 asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
673 {
674 struct path path;
675 int error;
676
677 error = user_path(filename, &path);
678 if (error)
679 goto out;
680 error = mnt_want_write(path.mnt);
681 if (error)
682 goto out_release;
683 error = chown_common(path.dentry, user, group);
684 mnt_drop_write(path.mnt);
685 out_release:
686 path_put(&path);
687 out:
688 return error;
689 }
690
691 asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
692 gid_t group, int flag)
693 {
694 struct path path;
695 int error = -EINVAL;
696 int follow;
697
698 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
699 goto out;
700
701 follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
702 error = user_path_at(dfd, filename, follow, &path);
703 if (error)
704 goto out;
705 error = mnt_want_write(path.mnt);
706 if (error)
707 goto out_release;
708 error = chown_common(path.dentry, user, group);
709 mnt_drop_write(path.mnt);
710 out_release:
711 path_put(&path);
712 out:
713 return error;
714 }
715
716 asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group)
717 {
718 struct path path;
719 int error;
720
721 error = user_lpath(filename, &path);
722 if (error)
723 goto out;
724 error = mnt_want_write(path.mnt);
725 if (error)
726 goto out_release;
727 error = chown_common(path.dentry, user, group);
728 mnt_drop_write(path.mnt);
729 out_release:
730 path_put(&path);
731 out:
732 return error;
733 }
734
735
736 asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
737 {
738 struct file * file;
739 int error = -EBADF;
740 struct dentry * dentry;
741
742 file = fget(fd);
743 if (!file)
744 goto out;
745
746 error = mnt_want_write(file->f_path.mnt);
747 if (error)
748 goto out_fput;
749 dentry = file->f_path.dentry;
750 audit_inode(NULL, dentry);
751 error = chown_common(dentry, user, group);
752 mnt_drop_write(file->f_path.mnt);
753 out_fput:
754 fput(file);
755 out:
756 return error;
757 }
758
759 /*
760 * You have to be very careful that these write
761 * counts get cleaned up in error cases and
762 * upon __fput(). This should probably never
763 * be called outside of __dentry_open().
764 */
765 static inline int __get_file_write_access(struct inode *inode,
766 struct vfsmount *mnt)
767 {
768 int error;
769 error = get_write_access(inode);
770 if (error)
771 return error;
772 /*
773 * Do not take mount writer counts on
774 * special files since no writes to
775 * the mount itself will occur.
776 */
777 if (!special_file(inode->i_mode)) {
778 /*
779 * Balanced in __fput()
780 */
781 error = mnt_want_write(mnt);
782 if (error)
783 put_write_access(inode);
784 }
785 return error;
786 }
787
788 static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
789 int flags, struct file *f,
790 int (*open)(struct inode *, struct file *),
791 const struct cred *cred)
792 {
793 struct inode *inode;
794 int error;
795
796 f->f_flags = flags;
797 f->f_mode = (__force fmode_t)((flags+1) & O_ACCMODE) | FMODE_LSEEK |
798 FMODE_PREAD | FMODE_PWRITE;
799 inode = dentry->d_inode;
800 if (f->f_mode & FMODE_WRITE) {
801 error = __get_file_write_access(inode, mnt);
802 if (error)
803 goto cleanup_file;
804 if (!special_file(inode->i_mode))
805 file_take_write(f);
806 }
807
808 f->f_mapping = inode->i_mapping;
809 f->f_path.dentry = dentry;
810 f->f_path.mnt = mnt;
811 f->f_pos = 0;
812 f->f_op = fops_get(inode->i_fop);
813 file_move(f, &inode->i_sb->s_files);
814
815 error = security_dentry_open(f, cred);
816 if (error)
817 goto cleanup_all;
818
819 if (!open && f->f_op)
820 open = f->f_op->open;
821 if (open) {
822 error = open(inode, f);
823 if (error)
824 goto cleanup_all;
825 }
826
827 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
828
829 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
830
831 /* NB: we're sure to have correct a_ops only after f_op->open */
832 if (f->f_flags & O_DIRECT) {
833 if (!f->f_mapping->a_ops ||
834 ((!f->f_mapping->a_ops->direct_IO) &&
835 (!f->f_mapping->a_ops->get_xip_mem))) {
836 fput(f);
837 f = ERR_PTR(-EINVAL);
838 }
839 }
840
841 return f;
842
843 cleanup_all:
844 fops_put(f->f_op);
845 if (f->f_mode & FMODE_WRITE) {
846 put_write_access(inode);
847 if (!special_file(inode->i_mode)) {
848 /*
849 * We don't consider this a real
850 * mnt_want/drop_write() pair
851 * because it all happenend right
852 * here, so just reset the state.
853 */
854 file_reset_write(f);
855 mnt_drop_write(mnt);
856 }
857 }
858 file_kill(f);
859 f->f_path.dentry = NULL;
860 f->f_path.mnt = NULL;
861 cleanup_file:
862 put_filp(f);
863 dput(dentry);
864 mntput(mnt);
865 return ERR_PTR(error);
866 }
867
868 /**
869 * lookup_instantiate_filp - instantiates the open intent filp
870 * @nd: pointer to nameidata
871 * @dentry: pointer to dentry
872 * @open: open callback
873 *
874 * Helper for filesystems that want to use lookup open intents and pass back
875 * a fully instantiated struct file to the caller.
876 * This function is meant to be called from within a filesystem's
877 * lookup method.
878 * Beware of calling it for non-regular files! Those ->open methods might block
879 * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
880 * leading to a deadlock, as nobody can open that fifo anymore, because
881 * another process to open fifo will block on locked parent when doing lookup).
882 * Note that in case of error, nd->intent.open.file is destroyed, but the
883 * path information remains valid.
884 * If the open callback is set to NULL, then the standard f_op->open()
885 * filesystem callback is substituted.
886 */
887 struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
888 int (*open)(struct inode *, struct file *))
889 {
890 const struct cred *cred = current_cred();
891
892 if (IS_ERR(nd->intent.open.file))
893 goto out;
894 if (IS_ERR(dentry))
895 goto out_err;
896 nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
897 nd->intent.open.flags - 1,
898 nd->intent.open.file,
899 open, cred);
900 out:
901 return nd->intent.open.file;
902 out_err:
903 release_open_intent(nd);
904 nd->intent.open.file = (struct file *)dentry;
905 goto out;
906 }
907 EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
908
909 /**
910 * nameidata_to_filp - convert a nameidata to an open filp.
911 * @nd: pointer to nameidata
912 * @flags: open flags
913 *
914 * Note that this function destroys the original nameidata
915 */
916 struct file *nameidata_to_filp(struct nameidata *nd, int flags)
917 {
918 const struct cred *cred = current_cred();
919 struct file *filp;
920
921 /* Pick up the filp from the open intent */
922 filp = nd->intent.open.file;
923 /* Has the filesystem initialised the file for us? */
924 if (filp->f_path.dentry == NULL)
925 filp = __dentry_open(nd->path.dentry, nd->path.mnt, flags, filp,
926 NULL, cred);
927 else
928 path_put(&nd->path);
929 return filp;
930 }
931
932 /*
933 * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
934 * error.
935 */
936 struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
937 const struct cred *cred)
938 {
939 int error;
940 struct file *f;
941
942 /*
943 * We must always pass in a valid mount pointer. Historically
944 * callers got away with not passing it, but we must enforce this at
945 * the earliest possible point now to avoid strange problems deep in the
946 * filesystem stack.
947 */
948 if (!mnt) {
949 printk(KERN_WARNING "%s called with NULL vfsmount\n", __func__);
950 dump_stack();
951 return ERR_PTR(-EINVAL);
952 }
953
954 error = -ENFILE;
955 f = get_empty_filp();
956 if (f == NULL) {
957 dput(dentry);
958 mntput(mnt);
959 return ERR_PTR(error);
960 }
961
962 return __dentry_open(dentry, mnt, flags, f, NULL, cred);
963 }
964 EXPORT_SYMBOL(dentry_open);
965
966 static void __put_unused_fd(struct files_struct *files, unsigned int fd)
967 {
968 struct fdtable *fdt = files_fdtable(files);
969 __FD_CLR(fd, fdt->open_fds);
970 if (fd < files->next_fd)
971 files->next_fd = fd;
972 }
973
974 void put_unused_fd(unsigned int fd)
975 {
976 struct files_struct *files = current->files;
977 spin_lock(&files->file_lock);
978 __put_unused_fd(files, fd);
979 spin_unlock(&files->file_lock);
980 }
981
982 EXPORT_SYMBOL(put_unused_fd);
983
984 /*
985 * Install a file pointer in the fd array.
986 *
987 * The VFS is full of places where we drop the files lock between
988 * setting the open_fds bitmap and installing the file in the file
989 * array. At any such point, we are vulnerable to a dup2() race
990 * installing a file in the array before us. We need to detect this and
991 * fput() the struct file we are about to overwrite in this case.
992 *
993 * It should never happen - if we allow dup2() do it, _really_ bad things
994 * will follow.
995 */
996
997 void fd_install(unsigned int fd, struct file *file)
998 {
999 struct files_struct *files = current->files;
1000 struct fdtable *fdt;
1001 spin_lock(&files->file_lock);
1002 fdt = files_fdtable(files);
1003 BUG_ON(fdt->fd[fd] != NULL);
1004 rcu_assign_pointer(fdt->fd[fd], file);
1005 spin_unlock(&files->file_lock);
1006 }
1007
1008 EXPORT_SYMBOL(fd_install);
1009
1010 long do_sys_open(int dfd, const char __user *filename, int flags, int mode)
1011 {
1012 char *tmp = getname(filename);
1013 int fd = PTR_ERR(tmp);
1014
1015 if (!IS_ERR(tmp)) {
1016 fd = get_unused_fd_flags(flags);
1017 if (fd >= 0) {
1018 struct file *f = do_filp_open(dfd, tmp, flags, mode);
1019 if (IS_ERR(f)) {
1020 put_unused_fd(fd);
1021 fd = PTR_ERR(f);
1022 } else {
1023 fsnotify_open(f->f_path.dentry);
1024 fd_install(fd, f);
1025 }
1026 }
1027 putname(tmp);
1028 }
1029 return fd;
1030 }
1031
1032 asmlinkage long sys_open(const char __user *filename, int flags, int mode)
1033 {
1034 long ret;
1035
1036 if (force_o_largefile())
1037 flags |= O_LARGEFILE;
1038
1039 ret = do_sys_open(AT_FDCWD, filename, flags, mode);
1040 /* avoid REGPARM breakage on x86: */
1041 asmlinkage_protect(3, ret, filename, flags, mode);
1042 return ret;
1043 }
1044
1045 asmlinkage long sys_openat(int dfd, const char __user *filename, int flags,
1046 int mode)
1047 {
1048 long ret;
1049
1050 if (force_o_largefile())
1051 flags |= O_LARGEFILE;
1052
1053 ret = do_sys_open(dfd, filename, flags, mode);
1054 /* avoid REGPARM breakage on x86: */
1055 asmlinkage_protect(4, ret, dfd, filename, flags, mode);
1056 return ret;
1057 }
1058
1059 #ifndef __alpha__
1060
1061 /*
1062 * For backward compatibility? Maybe this should be moved
1063 * into arch/i386 instead?
1064 */
1065 asmlinkage long sys_creat(const char __user * pathname, int mode)
1066 {
1067 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1068 }
1069
1070 #endif
1071
1072 /*
1073 * "id" is the POSIX thread ID. We use the
1074 * files pointer for this..
1075 */
1076 int filp_close(struct file *filp, fl_owner_t id)
1077 {
1078 int retval = 0;
1079
1080 if (!file_count(filp)) {
1081 printk(KERN_ERR "VFS: Close: file count is 0\n");
1082 return 0;
1083 }
1084
1085 if (filp->f_op && filp->f_op->flush)
1086 retval = filp->f_op->flush(filp, id);
1087
1088 dnotify_flush(filp, id);
1089 locks_remove_posix(filp, id);
1090 fput(filp);
1091 return retval;
1092 }
1093
1094 EXPORT_SYMBOL(filp_close);
1095
1096 /*
1097 * Careful here! We test whether the file pointer is NULL before
1098 * releasing the fd. This ensures that one clone task can't release
1099 * an fd while another clone is opening it.
1100 */
1101 asmlinkage long sys_close(unsigned int fd)
1102 {
1103 struct file * filp;
1104 struct files_struct *files = current->files;
1105 struct fdtable *fdt;
1106 int retval;
1107
1108 spin_lock(&files->file_lock);
1109 fdt = files_fdtable(files);
1110 if (fd >= fdt->max_fds)
1111 goto out_unlock;
1112 filp = fdt->fd[fd];
1113 if (!filp)
1114 goto out_unlock;
1115 rcu_assign_pointer(fdt->fd[fd], NULL);
1116 FD_CLR(fd, fdt->close_on_exec);
1117 __put_unused_fd(files, fd);
1118 spin_unlock(&files->file_lock);
1119 retval = filp_close(filp, files);
1120
1121 /* can't restart close syscall because file table entry was cleared */
1122 if (unlikely(retval == -ERESTARTSYS ||
1123 retval == -ERESTARTNOINTR ||
1124 retval == -ERESTARTNOHAND ||
1125 retval == -ERESTART_RESTARTBLOCK))
1126 retval = -EINTR;
1127
1128 return retval;
1129
1130 out_unlock:
1131 spin_unlock(&files->file_lock);
1132 return -EBADF;
1133 }
1134
1135 EXPORT_SYMBOL(sys_close);
1136
1137 /*
1138 * This routine simulates a hangup on the tty, to arrange that users
1139 * are given clean terminals at login time.
1140 */
1141 asmlinkage long sys_vhangup(void)
1142 {
1143 if (capable(CAP_SYS_TTY_CONFIG)) {
1144 tty_vhangup_self();
1145 return 0;
1146 }
1147 return -EPERM;
1148 }
1149
1150 /*
1151 * Called when an inode is about to be open.
1152 * We use this to disallow opening large files on 32bit systems if
1153 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1154 * on this flag in sys_open.
1155 */
1156 int generic_file_open(struct inode * inode, struct file * filp)
1157 {
1158 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1159 return -EOVERFLOW;
1160 return 0;
1161 }
1162
1163 EXPORT_SYMBOL(generic_file_open);
1164
1165 /*
1166 * This is used by subsystems that don't want seekable
1167 * file descriptors
1168 */
1169 int nonseekable_open(struct inode *inode, struct file *filp)
1170 {
1171 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1172 return 0;
1173 }
1174
1175 EXPORT_SYMBOL(nonseekable_open);
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