blob: f0d90cf0495c490316d427e309c38695ceb4e005 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/utime.h>
10#include <linux/file.h>
11#include <linux/smp_lock.h>
12#include <linux/quotaops.h>
Robert Love0eeca282005-07-12 17:06:03 -040013#include <linux/fsnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/tty.h>
17#include <linux/namei.h>
18#include <linux/backing-dev.h>
19#include <linux/security.h>
20#include <linux/mount.h>
21#include <linux/vfs.h>
22#include <asm/uaccess.h>
23#include <linux/fs.h>
Yoav Zachef3daed2005-06-23 00:09:58 -070024#include <linux/personality.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/pagemap.h>
26#include <linux/syscalls.h>
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070027#include <linux/rcupdate.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
29#include <asm/unistd.h>
30
31int vfs_statfs(struct super_block *sb, struct kstatfs *buf)
32{
33 int retval = -ENODEV;
34
35 if (sb) {
36 retval = -ENOSYS;
37 if (sb->s_op->statfs) {
38 memset(buf, 0, sizeof(*buf));
39 retval = security_sb_statfs(sb);
40 if (retval)
41 return retval;
42 retval = sb->s_op->statfs(sb, buf);
43 if (retval == 0 && buf->f_frsize == 0)
44 buf->f_frsize = buf->f_bsize;
45 }
46 }
47 return retval;
48}
49
50EXPORT_SYMBOL(vfs_statfs);
51
52static int vfs_statfs_native(struct super_block *sb, struct statfs *buf)
53{
54 struct kstatfs st;
55 int retval;
56
57 retval = vfs_statfs(sb, &st);
58 if (retval)
59 return retval;
60
61 if (sizeof(*buf) == sizeof(st))
62 memcpy(buf, &st, sizeof(st));
63 else {
64 if (sizeof buf->f_blocks == 4) {
65 if ((st.f_blocks | st.f_bfree | st.f_bavail) &
66 0xffffffff00000000ULL)
67 return -EOVERFLOW;
68 /*
69 * f_files and f_ffree may be -1; it's okay to stuff
70 * that into 32 bits
71 */
72 if (st.f_files != -1 &&
73 (st.f_files & 0xffffffff00000000ULL))
74 return -EOVERFLOW;
75 if (st.f_ffree != -1 &&
76 (st.f_ffree & 0xffffffff00000000ULL))
77 return -EOVERFLOW;
78 }
79
80 buf->f_type = st.f_type;
81 buf->f_bsize = st.f_bsize;
82 buf->f_blocks = st.f_blocks;
83 buf->f_bfree = st.f_bfree;
84 buf->f_bavail = st.f_bavail;
85 buf->f_files = st.f_files;
86 buf->f_ffree = st.f_ffree;
87 buf->f_fsid = st.f_fsid;
88 buf->f_namelen = st.f_namelen;
89 buf->f_frsize = st.f_frsize;
90 memset(buf->f_spare, 0, sizeof(buf->f_spare));
91 }
92 return 0;
93}
94
95static int vfs_statfs64(struct super_block *sb, struct statfs64 *buf)
96{
97 struct kstatfs st;
98 int retval;
99
100 retval = vfs_statfs(sb, &st);
101 if (retval)
102 return retval;
103
104 if (sizeof(*buf) == sizeof(st))
105 memcpy(buf, &st, sizeof(st));
106 else {
107 buf->f_type = st.f_type;
108 buf->f_bsize = st.f_bsize;
109 buf->f_blocks = st.f_blocks;
110 buf->f_bfree = st.f_bfree;
111 buf->f_bavail = st.f_bavail;
112 buf->f_files = st.f_files;
113 buf->f_ffree = st.f_ffree;
114 buf->f_fsid = st.f_fsid;
115 buf->f_namelen = st.f_namelen;
116 buf->f_frsize = st.f_frsize;
117 memset(buf->f_spare, 0, sizeof(buf->f_spare));
118 }
119 return 0;
120}
121
122asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf)
123{
124 struct nameidata nd;
125 int error;
126
127 error = user_path_walk(path, &nd);
128 if (!error) {
129 struct statfs tmp;
130 error = vfs_statfs_native(nd.dentry->d_inode->i_sb, &tmp);
131 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
132 error = -EFAULT;
133 path_release(&nd);
134 }
135 return error;
136}
137
138
139asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf)
140{
141 struct nameidata nd;
142 long error;
143
144 if (sz != sizeof(*buf))
145 return -EINVAL;
146 error = user_path_walk(path, &nd);
147 if (!error) {
148 struct statfs64 tmp;
149 error = vfs_statfs64(nd.dentry->d_inode->i_sb, &tmp);
150 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
151 error = -EFAULT;
152 path_release(&nd);
153 }
154 return error;
155}
156
157
158asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf)
159{
160 struct file * file;
161 struct statfs tmp;
162 int error;
163
164 error = -EBADF;
165 file = fget(fd);
166 if (!file)
167 goto out;
168 error = vfs_statfs_native(file->f_dentry->d_inode->i_sb, &tmp);
169 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
170 error = -EFAULT;
171 fput(file);
172out:
173 return error;
174}
175
176asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf)
177{
178 struct file * file;
179 struct statfs64 tmp;
180 int error;
181
182 if (sz != sizeof(*buf))
183 return -EINVAL;
184
185 error = -EBADF;
186 file = fget(fd);
187 if (!file)
188 goto out;
189 error = vfs_statfs64(file->f_dentry->d_inode->i_sb, &tmp);
190 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
191 error = -EFAULT;
192 fput(file);
193out:
194 return error;
195}
196
197int do_truncate(struct dentry *dentry, loff_t length)
198{
199 int err;
200 struct iattr newattrs;
201
202 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
203 if (length < 0)
204 return -EINVAL;
205
206 newattrs.ia_size = length;
207 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
208
209 down(&dentry->d_inode->i_sem);
210 err = notify_change(dentry, &newattrs);
211 up(&dentry->d_inode->i_sem);
212 return err;
213}
214
215static inline long do_sys_truncate(const char __user * path, loff_t length)
216{
217 struct nameidata nd;
218 struct inode * inode;
219 int error;
220
221 error = -EINVAL;
222 if (length < 0) /* sorry, but loff_t says... */
223 goto out;
224
225 error = user_path_walk(path, &nd);
226 if (error)
227 goto out;
228 inode = nd.dentry->d_inode;
229
230 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
231 error = -EISDIR;
232 if (S_ISDIR(inode->i_mode))
233 goto dput_and_out;
234
235 error = -EINVAL;
236 if (!S_ISREG(inode->i_mode))
237 goto dput_and_out;
238
239 error = permission(inode,MAY_WRITE,&nd);
240 if (error)
241 goto dput_and_out;
242
243 error = -EROFS;
244 if (IS_RDONLY(inode))
245 goto dput_and_out;
246
247 error = -EPERM;
248 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
249 goto dput_and_out;
250
251 /*
252 * Make sure that there are no leases.
253 */
254 error = break_lease(inode, FMODE_WRITE);
255 if (error)
256 goto dput_and_out;
257
258 error = get_write_access(inode);
259 if (error)
260 goto dput_and_out;
261
262 error = locks_verify_truncate(inode, NULL, length);
263 if (!error) {
264 DQUOT_INIT(inode);
265 error = do_truncate(nd.dentry, length);
266 }
267 put_write_access(inode);
268
269dput_and_out:
270 path_release(&nd);
271out:
272 return error;
273}
274
275asmlinkage long sys_truncate(const char __user * path, unsigned long length)
276{
277 /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
278 return do_sys_truncate(path, (long)length);
279}
280
281static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
282{
283 struct inode * inode;
284 struct dentry *dentry;
285 struct file * file;
286 int error;
287
288 error = -EINVAL;
289 if (length < 0)
290 goto out;
291 error = -EBADF;
292 file = fget(fd);
293 if (!file)
294 goto out;
295
296 /* explicitly opened as large or we are on 64-bit box */
297 if (file->f_flags & O_LARGEFILE)
298 small = 0;
299
300 dentry = file->f_dentry;
301 inode = dentry->d_inode;
302 error = -EINVAL;
303 if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
304 goto out_putf;
305
306 error = -EINVAL;
307 /* Cannot ftruncate over 2^31 bytes without large file support */
308 if (small && length > MAX_NON_LFS)
309 goto out_putf;
310
311 error = -EPERM;
312 if (IS_APPEND(inode))
313 goto out_putf;
314
315 error = locks_verify_truncate(inode, file, length);
316 if (!error)
317 error = do_truncate(dentry, length);
318out_putf:
319 fput(file);
320out:
321 return error;
322}
323
324asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
325{
326 return do_sys_ftruncate(fd, length, 1);
327}
328
329/* LFS versions of truncate are only needed on 32 bit machines */
330#if BITS_PER_LONG == 32
331asmlinkage long sys_truncate64(const char __user * path, loff_t length)
332{
333 return do_sys_truncate(path, length);
334}
335
336asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
337{
338 return do_sys_ftruncate(fd, length, 0);
339}
340#endif
341
342#ifdef __ARCH_WANT_SYS_UTIME
343
344/*
345 * sys_utime() can be implemented in user-level using sys_utimes().
346 * Is this for backwards compatibility? If so, why not move it
347 * into the appropriate arch directory (for those architectures that
348 * need it).
349 */
350
351/* If times==NULL, set access and modification to current time,
352 * must be owner or have write permission.
353 * Else, update from *times, must be owner or super user.
354 */
355asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
356{
357 int error;
358 struct nameidata nd;
359 struct inode * inode;
360 struct iattr newattrs;
361
362 error = user_path_walk(filename, &nd);
363 if (error)
364 goto out;
365 inode = nd.dentry->d_inode;
366
367 error = -EROFS;
368 if (IS_RDONLY(inode))
369 goto dput_and_out;
370
371 /* Don't worry, the checks are done in inode_change_ok() */
372 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
373 if (times) {
374 error = -EPERM;
375 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
376 goto dput_and_out;
377
378 error = get_user(newattrs.ia_atime.tv_sec, &times->actime);
379 newattrs.ia_atime.tv_nsec = 0;
380 if (!error)
381 error = get_user(newattrs.ia_mtime.tv_sec, &times->modtime);
382 newattrs.ia_mtime.tv_nsec = 0;
383 if (error)
384 goto dput_and_out;
385
386 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
387 } else {
388 error = -EACCES;
389 if (IS_IMMUTABLE(inode))
390 goto dput_and_out;
391
392 if (current->fsuid != inode->i_uid &&
393 (error = permission(inode,MAY_WRITE,&nd)) != 0)
394 goto dput_and_out;
395 }
396 down(&inode->i_sem);
397 error = notify_change(nd.dentry, &newattrs);
398 up(&inode->i_sem);
399dput_and_out:
400 path_release(&nd);
401out:
402 return error;
403}
404
405#endif
406
407/* If times==NULL, set access and modification to current time,
408 * must be owner or have write permission.
409 * Else, update from *times, must be owner or super user.
410 */
411long do_utimes(char __user * filename, struct timeval * times)
412{
413 int error;
414 struct nameidata nd;
415 struct inode * inode;
416 struct iattr newattrs;
417
418 error = user_path_walk(filename, &nd);
419
420 if (error)
421 goto out;
422 inode = nd.dentry->d_inode;
423
424 error = -EROFS;
425 if (IS_RDONLY(inode))
426 goto dput_and_out;
427
428 /* Don't worry, the checks are done in inode_change_ok() */
429 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
430 if (times) {
431 error = -EPERM;
432 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
433 goto dput_and_out;
434
435 newattrs.ia_atime.tv_sec = times[0].tv_sec;
436 newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000;
437 newattrs.ia_mtime.tv_sec = times[1].tv_sec;
438 newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000;
439 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
440 } else {
441 error = -EACCES;
442 if (IS_IMMUTABLE(inode))
443 goto dput_and_out;
444
445 if (current->fsuid != inode->i_uid &&
446 (error = permission(inode,MAY_WRITE,&nd)) != 0)
447 goto dput_and_out;
448 }
449 down(&inode->i_sem);
450 error = notify_change(nd.dentry, &newattrs);
451 up(&inode->i_sem);
452dput_and_out:
453 path_release(&nd);
454out:
455 return error;
456}
457
458asmlinkage long sys_utimes(char __user * filename, struct timeval __user * utimes)
459{
460 struct timeval times[2];
461
462 if (utimes && copy_from_user(&times, utimes, sizeof(times)))
463 return -EFAULT;
464 return do_utimes(filename, utimes ? times : NULL);
465}
466
467
468/*
469 * access() needs to use the real uid/gid, not the effective uid/gid.
470 * We do this by temporarily clearing all FS-related capabilities and
471 * switching the fsuid/fsgid around to the real ones.
472 */
473asmlinkage long sys_access(const char __user * filename, int mode)
474{
475 struct nameidata nd;
476 int old_fsuid, old_fsgid;
477 kernel_cap_t old_cap;
478 int res;
479
480 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
481 return -EINVAL;
482
483 old_fsuid = current->fsuid;
484 old_fsgid = current->fsgid;
485 old_cap = current->cap_effective;
486
487 current->fsuid = current->uid;
488 current->fsgid = current->gid;
489
490 /*
491 * Clear the capabilities if we switch to a non-root user
492 *
493 * FIXME: There is a race here against sys_capset. The
494 * capabilities can change yet we will restore the old
495 * value below. We should hold task_capabilities_lock,
496 * but we cannot because user_path_walk can sleep.
497 */
498 if (current->uid)
499 cap_clear(current->cap_effective);
500 else
501 current->cap_effective = current->cap_permitted;
502
503 res = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd);
504 if (!res) {
505 res = permission(nd.dentry->d_inode, mode, &nd);
506 /* SuS v2 requires we report a read only fs too */
507 if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode)
508 && !special_file(nd.dentry->d_inode->i_mode))
509 res = -EROFS;
510 path_release(&nd);
511 }
512
513 current->fsuid = old_fsuid;
514 current->fsgid = old_fsgid;
515 current->cap_effective = old_cap;
516
517 return res;
518}
519
520asmlinkage long sys_chdir(const char __user * filename)
521{
522 struct nameidata nd;
523 int error;
524
525 error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd);
526 if (error)
527 goto out;
528
529 error = permission(nd.dentry->d_inode,MAY_EXEC,&nd);
530 if (error)
531 goto dput_and_out;
532
533 set_fs_pwd(current->fs, nd.mnt, nd.dentry);
534
535dput_and_out:
536 path_release(&nd);
537out:
538 return error;
539}
540
541asmlinkage long sys_fchdir(unsigned int fd)
542{
543 struct file *file;
544 struct dentry *dentry;
545 struct inode *inode;
546 struct vfsmount *mnt;
547 int error;
548
549 error = -EBADF;
550 file = fget(fd);
551 if (!file)
552 goto out;
553
554 dentry = file->f_dentry;
555 mnt = file->f_vfsmnt;
556 inode = dentry->d_inode;
557
558 error = -ENOTDIR;
559 if (!S_ISDIR(inode->i_mode))
560 goto out_putf;
561
562 error = permission(inode, MAY_EXEC, NULL);
563 if (!error)
564 set_fs_pwd(current->fs, mnt, dentry);
565out_putf:
566 fput(file);
567out:
568 return error;
569}
570
571asmlinkage long sys_chroot(const char __user * filename)
572{
573 struct nameidata nd;
574 int error;
575
576 error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd);
577 if (error)
578 goto out;
579
580 error = permission(nd.dentry->d_inode,MAY_EXEC,&nd);
581 if (error)
582 goto dput_and_out;
583
584 error = -EPERM;
585 if (!capable(CAP_SYS_CHROOT))
586 goto dput_and_out;
587
588 set_fs_root(current->fs, nd.mnt, nd.dentry);
589 set_fs_altroot();
590 error = 0;
591dput_and_out:
592 path_release(&nd);
593out:
594 return error;
595}
596
597asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
598{
599 struct inode * inode;
600 struct dentry * dentry;
601 struct file * file;
602 int err = -EBADF;
603 struct iattr newattrs;
604
605 file = fget(fd);
606 if (!file)
607 goto out;
608
609 dentry = file->f_dentry;
610 inode = dentry->d_inode;
611
612 err = -EROFS;
613 if (IS_RDONLY(inode))
614 goto out_putf;
615 err = -EPERM;
616 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
617 goto out_putf;
618 down(&inode->i_sem);
619 if (mode == (mode_t) -1)
620 mode = inode->i_mode;
621 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
622 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
623 err = notify_change(dentry, &newattrs);
624 up(&inode->i_sem);
625
626out_putf:
627 fput(file);
628out:
629 return err;
630}
631
632asmlinkage long sys_chmod(const char __user * filename, mode_t mode)
633{
634 struct nameidata nd;
635 struct inode * inode;
636 int error;
637 struct iattr newattrs;
638
639 error = user_path_walk(filename, &nd);
640 if (error)
641 goto out;
642 inode = nd.dentry->d_inode;
643
644 error = -EROFS;
645 if (IS_RDONLY(inode))
646 goto dput_and_out;
647
648 error = -EPERM;
649 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
650 goto dput_and_out;
651
652 down(&inode->i_sem);
653 if (mode == (mode_t) -1)
654 mode = inode->i_mode;
655 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
656 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
657 error = notify_change(nd.dentry, &newattrs);
658 up(&inode->i_sem);
659
660dput_and_out:
661 path_release(&nd);
662out:
663 return error;
664}
665
666static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
667{
668 struct inode * inode;
669 int error;
670 struct iattr newattrs;
671
672 error = -ENOENT;
673 if (!(inode = dentry->d_inode)) {
674 printk(KERN_ERR "chown_common: NULL inode\n");
675 goto out;
676 }
677 error = -EROFS;
678 if (IS_RDONLY(inode))
679 goto out;
680 error = -EPERM;
681 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
682 goto out;
683 newattrs.ia_valid = ATTR_CTIME;
684 if (user != (uid_t) -1) {
685 newattrs.ia_valid |= ATTR_UID;
686 newattrs.ia_uid = user;
687 }
688 if (group != (gid_t) -1) {
689 newattrs.ia_valid |= ATTR_GID;
690 newattrs.ia_gid = group;
691 }
692 if (!S_ISDIR(inode->i_mode))
693 newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID;
694 down(&inode->i_sem);
695 error = notify_change(dentry, &newattrs);
696 up(&inode->i_sem);
697out:
698 return error;
699}
700
701asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
702{
703 struct nameidata nd;
704 int error;
705
706 error = user_path_walk(filename, &nd);
707 if (!error) {
708 error = chown_common(nd.dentry, user, group);
709 path_release(&nd);
710 }
711 return error;
712}
713
714asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group)
715{
716 struct nameidata nd;
717 int error;
718
719 error = user_path_walk_link(filename, &nd);
720 if (!error) {
721 error = chown_common(nd.dentry, user, group);
722 path_release(&nd);
723 }
724 return error;
725}
726
727
728asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
729{
730 struct file * file;
731 int error = -EBADF;
732
733 file = fget(fd);
734 if (file) {
735 error = chown_common(file->f_dentry, user, group);
736 fput(file);
737 }
738 return error;
739}
740
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700741static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
742 int flags, struct file *f)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 struct inode *inode;
745 int error;
746
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 f->f_flags = flags;
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700748 f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK |
749 FMODE_PREAD | FMODE_PWRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 inode = dentry->d_inode;
751 if (f->f_mode & FMODE_WRITE) {
752 error = get_write_access(inode);
753 if (error)
754 goto cleanup_file;
755 }
756
757 f->f_mapping = inode->i_mapping;
758 f->f_dentry = dentry;
759 f->f_vfsmnt = mnt;
760 f->f_pos = 0;
761 f->f_op = fops_get(inode->i_fop);
762 file_move(f, &inode->i_sb->s_files);
763
764 if (f->f_op && f->f_op->open) {
765 error = f->f_op->open(inode,f);
766 if (error)
767 goto cleanup_all;
768 }
769 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
770
771 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
772
773 /* NB: we're sure to have correct a_ops only after f_op->open */
774 if (f->f_flags & O_DIRECT) {
Carsten Otteceffc072005-06-23 22:05:25 -0700775 if (!f->f_mapping->a_ops ||
776 ((!f->f_mapping->a_ops->direct_IO) &&
777 (!f->f_mapping->a_ops->get_xip_page))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 fput(f);
779 f = ERR_PTR(-EINVAL);
780 }
781 }
782
783 return f;
784
785cleanup_all:
786 fops_put(f->f_op);
787 if (f->f_mode & FMODE_WRITE)
788 put_write_access(inode);
789 file_kill(f);
790 f->f_dentry = NULL;
791 f->f_vfsmnt = NULL;
792cleanup_file:
793 put_filp(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 dput(dentry);
795 mntput(mnt);
796 return ERR_PTR(error);
797}
798
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700799/*
800 * Note that while the flag value (low two bits) for sys_open means:
801 * 00 - read-only
802 * 01 - write-only
803 * 10 - read-write
804 * 11 - special
805 * it is changed into
806 * 00 - no permissions needed
807 * 01 - read-permission
808 * 10 - write-permission
809 * 11 - read-write
810 * for the internal routines (ie open_namei()/follow_link() etc). 00 is
811 * used by symlinks.
812 */
813struct file *filp_open(const char * filename, int flags, int mode)
814{
815 int namei_flags, error;
816 struct nameidata nd;
817 struct file *f;
818
819 namei_flags = flags;
820 if ((namei_flags+1) & O_ACCMODE)
821 namei_flags++;
822 if (namei_flags & O_TRUNC)
823 namei_flags |= 2;
824
825 error = -ENFILE;
826 f = get_empty_filp();
827 if (f == NULL)
828 return ERR_PTR(error);
829
830 error = open_namei(filename, namei_flags, mode, &nd);
831 if (!error)
832 return __dentry_open(nd.dentry, nd.mnt, flags, f);
833
834 put_filp(f);
835 return ERR_PTR(error);
836}
837EXPORT_SYMBOL(filp_open);
838
839struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
840{
841 int error;
842 struct file *f;
843
844 error = -ENFILE;
845 f = get_empty_filp();
846 if (f == NULL)
847 return ERR_PTR(error);
848
849 return __dentry_open(dentry, mnt, flags, f);
850}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851EXPORT_SYMBOL(dentry_open);
852
853/*
854 * Find an empty file descriptor entry, and mark it busy.
855 */
856int get_unused_fd(void)
857{
858 struct files_struct * files = current->files;
859 int fd, error;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700860 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861
862 error = -EMFILE;
863 spin_lock(&files->file_lock);
864
865repeat:
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700866 fdt = files_fdtable(files);
867 fd = find_next_zero_bit(fdt->open_fds->fds_bits,
868 fdt->max_fdset,
869 fdt->next_fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870
871 /*
872 * N.B. For clone tasks sharing a files structure, this test
873 * will limit the total number of files that can be opened.
874 */
875 if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
876 goto out;
877
878 /* Do we need to expand the fd array or fd set? */
879 error = expand_files(files, fd);
880 if (error < 0)
881 goto out;
882
883 if (error) {
884 /*
885 * If we needed to expand the fs array we
886 * might have blocked - try again.
887 */
888 error = -EMFILE;
889 goto repeat;
890 }
891
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700892 FD_SET(fd, fdt->open_fds);
893 FD_CLR(fd, fdt->close_on_exec);
894 fdt->next_fd = fd + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895#if 1
896 /* Sanity check */
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700897 if (fdt->fd[fd] != NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700899 fdt->fd[fd] = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 }
901#endif
902 error = fd;
903
904out:
905 spin_unlock(&files->file_lock);
906 return error;
907}
908
909EXPORT_SYMBOL(get_unused_fd);
910
911static inline void __put_unused_fd(struct files_struct *files, unsigned int fd)
912{
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700913 struct fdtable *fdt = files_fdtable(files);
914 __FD_CLR(fd, fdt->open_fds);
915 if (fd < fdt->next_fd)
916 fdt->next_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917}
918
919void fastcall put_unused_fd(unsigned int fd)
920{
921 struct files_struct *files = current->files;
922 spin_lock(&files->file_lock);
923 __put_unused_fd(files, fd);
924 spin_unlock(&files->file_lock);
925}
926
927EXPORT_SYMBOL(put_unused_fd);
928
929/*
930 * Install a file pointer in the fd array.
931 *
932 * The VFS is full of places where we drop the files lock between
933 * setting the open_fds bitmap and installing the file in the file
934 * array. At any such point, we are vulnerable to a dup2() race
935 * installing a file in the array before us. We need to detect this and
936 * fput() the struct file we are about to overwrite in this case.
937 *
938 * It should never happen - if we allow dup2() do it, _really_ bad things
939 * will follow.
940 */
941
942void fastcall fd_install(unsigned int fd, struct file * file)
943{
944 struct files_struct *files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700945 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 spin_lock(&files->file_lock);
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700947 fdt = files_fdtable(files);
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -0700948 BUG_ON(fdt->fd[fd] != NULL);
949 rcu_assign_pointer(fdt->fd[fd], file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 spin_unlock(&files->file_lock);
951}
952
953EXPORT_SYMBOL(fd_install);
954
Miklos Szeredie922efc2005-09-06 15:18:25 -0700955long do_sys_open(const char __user *filename, int flags, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956{
Miklos Szeredie922efc2005-09-06 15:18:25 -0700957 char *tmp = getname(filename);
958 int fd = PTR_ERR(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 if (!IS_ERR(tmp)) {
961 fd = get_unused_fd();
962 if (fd >= 0) {
963 struct file *f = filp_open(tmp, flags, mode);
Telemaque Ndizihiwefed2fc12005-06-23 00:10:33 -0700964 if (IS_ERR(f)) {
965 put_unused_fd(fd);
966 fd = PTR_ERR(f);
967 } else {
Robert Love0eeca282005-07-12 17:06:03 -0400968 fsnotify_open(f->f_dentry);
Telemaque Ndizihiwefed2fc12005-06-23 00:10:33 -0700969 fd_install(fd, f);
970 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 putname(tmp);
973 }
974 return fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975}
Miklos Szeredie922efc2005-09-06 15:18:25 -0700976
977asmlinkage long sys_open(const char __user *filename, int flags, int mode)
978{
979 if (force_o_largefile())
980 flags |= O_LARGEFILE;
981
982 return do_sys_open(filename, flags, mode);
983}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984EXPORT_SYMBOL_GPL(sys_open);
985
986#ifndef __alpha__
987
988/*
989 * For backward compatibility? Maybe this should be moved
990 * into arch/i386 instead?
991 */
992asmlinkage long sys_creat(const char __user * pathname, int mode)
993{
994 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
995}
996
997#endif
998
999/*
1000 * "id" is the POSIX thread ID. We use the
1001 * files pointer for this..
1002 */
1003int filp_close(struct file *filp, fl_owner_t id)
1004{
Christoph Lameter45778ca2005-06-23 00:10:17 -07001005 int retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006
1007 if (!file_count(filp)) {
1008 printk(KERN_ERR "VFS: Close: file count is 0\n");
Christoph Lameter45778ca2005-06-23 00:10:17 -07001009 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 }
1011
Christoph Lameter45778ca2005-06-23 00:10:17 -07001012 if (filp->f_op && filp->f_op->flush)
1013 retval = filp->f_op->flush(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014
1015 dnotify_flush(filp, id);
1016 locks_remove_posix(filp, id);
1017 fput(filp);
1018 return retval;
1019}
1020
1021EXPORT_SYMBOL(filp_close);
1022
1023/*
1024 * Careful here! We test whether the file pointer is NULL before
1025 * releasing the fd. This ensures that one clone task can't release
1026 * an fd while another clone is opening it.
1027 */
1028asmlinkage long sys_close(unsigned int fd)
1029{
1030 struct file * filp;
1031 struct files_struct *files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001032 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033
1034 spin_lock(&files->file_lock);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001035 fdt = files_fdtable(files);
1036 if (fd >= fdt->max_fds)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 goto out_unlock;
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001038 filp = fdt->fd[fd];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 if (!filp)
1040 goto out_unlock;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -07001041 rcu_assign_pointer(fdt->fd[fd], NULL);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001042 FD_CLR(fd, fdt->close_on_exec);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 __put_unused_fd(files, fd);
1044 spin_unlock(&files->file_lock);
1045 return filp_close(filp, files);
1046
1047out_unlock:
1048 spin_unlock(&files->file_lock);
1049 return -EBADF;
1050}
1051
1052EXPORT_SYMBOL(sys_close);
1053
1054/*
1055 * This routine simulates a hangup on the tty, to arrange that users
1056 * are given clean terminals at login time.
1057 */
1058asmlinkage long sys_vhangup(void)
1059{
1060 if (capable(CAP_SYS_TTY_CONFIG)) {
1061 tty_vhangup(current->signal->tty);
1062 return 0;
1063 }
1064 return -EPERM;
1065}
1066
1067/*
1068 * Called when an inode is about to be open.
1069 * We use this to disallow opening large files on 32bit systems if
1070 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1071 * on this flag in sys_open.
1072 */
1073int generic_file_open(struct inode * inode, struct file * filp)
1074{
1075 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1076 return -EFBIG;
1077 return 0;
1078}
1079
1080EXPORT_SYMBOL(generic_file_open);
1081
1082/*
1083 * This is used by subsystems that don't want seekable
1084 * file descriptors
1085 */
1086int nonseekable_open(struct inode *inode, struct file *filp)
1087{
1088 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1089 return 0;
1090}
1091
1092EXPORT_SYMBOL(nonseekable_open);