blob: 2ebb72c1a876e22d3e164add4092e809cff1ed87 [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>
13#include <linux/dnotify.h>
14#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>
27
28#include <asm/unistd.h>
29
30int vfs_statfs(struct super_block *sb, struct kstatfs *buf)
31{
32 int retval = -ENODEV;
33
34 if (sb) {
35 retval = -ENOSYS;
36 if (sb->s_op->statfs) {
37 memset(buf, 0, sizeof(*buf));
38 retval = security_sb_statfs(sb);
39 if (retval)
40 return retval;
41 retval = sb->s_op->statfs(sb, buf);
42 if (retval == 0 && buf->f_frsize == 0)
43 buf->f_frsize = buf->f_bsize;
44 }
45 }
46 return retval;
47}
48
49EXPORT_SYMBOL(vfs_statfs);
50
51static int vfs_statfs_native(struct super_block *sb, struct statfs *buf)
52{
53 struct kstatfs st;
54 int retval;
55
56 retval = vfs_statfs(sb, &st);
57 if (retval)
58 return retval;
59
60 if (sizeof(*buf) == sizeof(st))
61 memcpy(buf, &st, sizeof(st));
62 else {
63 if (sizeof buf->f_blocks == 4) {
64 if ((st.f_blocks | st.f_bfree | st.f_bavail) &
65 0xffffffff00000000ULL)
66 return -EOVERFLOW;
67 /*
68 * f_files and f_ffree may be -1; it's okay to stuff
69 * that into 32 bits
70 */
71 if (st.f_files != -1 &&
72 (st.f_files & 0xffffffff00000000ULL))
73 return -EOVERFLOW;
74 if (st.f_ffree != -1 &&
75 (st.f_ffree & 0xffffffff00000000ULL))
76 return -EOVERFLOW;
77 }
78
79 buf->f_type = st.f_type;
80 buf->f_bsize = st.f_bsize;
81 buf->f_blocks = st.f_blocks;
82 buf->f_bfree = st.f_bfree;
83 buf->f_bavail = st.f_bavail;
84 buf->f_files = st.f_files;
85 buf->f_ffree = st.f_ffree;
86 buf->f_fsid = st.f_fsid;
87 buf->f_namelen = st.f_namelen;
88 buf->f_frsize = st.f_frsize;
89 memset(buf->f_spare, 0, sizeof(buf->f_spare));
90 }
91 return 0;
92}
93
94static int vfs_statfs64(struct super_block *sb, struct statfs64 *buf)
95{
96 struct kstatfs st;
97 int retval;
98
99 retval = vfs_statfs(sb, &st);
100 if (retval)
101 return retval;
102
103 if (sizeof(*buf) == sizeof(st))
104 memcpy(buf, &st, sizeof(st));
105 else {
106 buf->f_type = st.f_type;
107 buf->f_bsize = st.f_bsize;
108 buf->f_blocks = st.f_blocks;
109 buf->f_bfree = st.f_bfree;
110 buf->f_bavail = st.f_bavail;
111 buf->f_files = st.f_files;
112 buf->f_ffree = st.f_ffree;
113 buf->f_fsid = st.f_fsid;
114 buf->f_namelen = st.f_namelen;
115 buf->f_frsize = st.f_frsize;
116 memset(buf->f_spare, 0, sizeof(buf->f_spare));
117 }
118 return 0;
119}
120
121asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf)
122{
123 struct nameidata nd;
124 int error;
125
126 error = user_path_walk(path, &nd);
127 if (!error) {
128 struct statfs tmp;
129 error = vfs_statfs_native(nd.dentry->d_inode->i_sb, &tmp);
130 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
131 error = -EFAULT;
132 path_release(&nd);
133 }
134 return error;
135}
136
137
138asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf)
139{
140 struct nameidata nd;
141 long error;
142
143 if (sz != sizeof(*buf))
144 return -EINVAL;
145 error = user_path_walk(path, &nd);
146 if (!error) {
147 struct statfs64 tmp;
148 error = vfs_statfs64(nd.dentry->d_inode->i_sb, &tmp);
149 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
150 error = -EFAULT;
151 path_release(&nd);
152 }
153 return error;
154}
155
156
157asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf)
158{
159 struct file * file;
160 struct statfs tmp;
161 int error;
162
163 error = -EBADF;
164 file = fget(fd);
165 if (!file)
166 goto out;
167 error = vfs_statfs_native(file->f_dentry->d_inode->i_sb, &tmp);
168 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
169 error = -EFAULT;
170 fput(file);
171out:
172 return error;
173}
174
175asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf)
176{
177 struct file * file;
178 struct statfs64 tmp;
179 int error;
180
181 if (sz != sizeof(*buf))
182 return -EINVAL;
183
184 error = -EBADF;
185 file = fget(fd);
186 if (!file)
187 goto out;
188 error = vfs_statfs64(file->f_dentry->d_inode->i_sb, &tmp);
189 if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
190 error = -EFAULT;
191 fput(file);
192out:
193 return error;
194}
195
196int do_truncate(struct dentry *dentry, loff_t length)
197{
198 int err;
199 struct iattr newattrs;
200
201 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
202 if (length < 0)
203 return -EINVAL;
204
205 newattrs.ia_size = length;
206 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
207
208 down(&dentry->d_inode->i_sem);
209 err = notify_change(dentry, &newattrs);
210 up(&dentry->d_inode->i_sem);
211 return err;
212}
213
214static inline long do_sys_truncate(const char __user * path, loff_t length)
215{
216 struct nameidata nd;
217 struct inode * inode;
218 int error;
219
220 error = -EINVAL;
221 if (length < 0) /* sorry, but loff_t says... */
222 goto out;
223
224 error = user_path_walk(path, &nd);
225 if (error)
226 goto out;
227 inode = nd.dentry->d_inode;
228
229 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
230 error = -EISDIR;
231 if (S_ISDIR(inode->i_mode))
232 goto dput_and_out;
233
234 error = -EINVAL;
235 if (!S_ISREG(inode->i_mode))
236 goto dput_and_out;
237
238 error = permission(inode,MAY_WRITE,&nd);
239 if (error)
240 goto dput_and_out;
241
242 error = -EROFS;
243 if (IS_RDONLY(inode))
244 goto dput_and_out;
245
246 error = -EPERM;
247 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
248 goto dput_and_out;
249
250 /*
251 * Make sure that there are no leases.
252 */
253 error = break_lease(inode, FMODE_WRITE);
254 if (error)
255 goto dput_and_out;
256
257 error = get_write_access(inode);
258 if (error)
259 goto dput_and_out;
260
261 error = locks_verify_truncate(inode, NULL, length);
262 if (!error) {
263 DQUOT_INIT(inode);
264 error = do_truncate(nd.dentry, length);
265 }
266 put_write_access(inode);
267
268dput_and_out:
269 path_release(&nd);
270out:
271 return error;
272}
273
274asmlinkage long sys_truncate(const char __user * path, unsigned long length)
275{
276 /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
277 return do_sys_truncate(path, (long)length);
278}
279
280static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
281{
282 struct inode * inode;
283 struct dentry *dentry;
284 struct file * file;
285 int error;
286
287 error = -EINVAL;
288 if (length < 0)
289 goto out;
290 error = -EBADF;
291 file = fget(fd);
292 if (!file)
293 goto out;
294
295 /* explicitly opened as large or we are on 64-bit box */
296 if (file->f_flags & O_LARGEFILE)
297 small = 0;
298
299 dentry = file->f_dentry;
300 inode = dentry->d_inode;
301 error = -EINVAL;
302 if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
303 goto out_putf;
304
305 error = -EINVAL;
306 /* Cannot ftruncate over 2^31 bytes without large file support */
307 if (small && length > MAX_NON_LFS)
308 goto out_putf;
309
310 error = -EPERM;
311 if (IS_APPEND(inode))
312 goto out_putf;
313
314 error = locks_verify_truncate(inode, file, length);
315 if (!error)
316 error = do_truncate(dentry, length);
317out_putf:
318 fput(file);
319out:
320 return error;
321}
322
323asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
324{
325 return do_sys_ftruncate(fd, length, 1);
326}
327
328/* LFS versions of truncate are only needed on 32 bit machines */
329#if BITS_PER_LONG == 32
330asmlinkage long sys_truncate64(const char __user * path, loff_t length)
331{
332 return do_sys_truncate(path, length);
333}
334
335asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
336{
337 return do_sys_ftruncate(fd, length, 0);
338}
339#endif
340
341#ifdef __ARCH_WANT_SYS_UTIME
342
343/*
344 * sys_utime() can be implemented in user-level using sys_utimes().
345 * Is this for backwards compatibility? If so, why not move it
346 * into the appropriate arch directory (for those architectures that
347 * need it).
348 */
349
350/* If times==NULL, set access and modification to current time,
351 * must be owner or have write permission.
352 * Else, update from *times, must be owner or super user.
353 */
354asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
355{
356 int error;
357 struct nameidata nd;
358 struct inode * inode;
359 struct iattr newattrs;
360
361 error = user_path_walk(filename, &nd);
362 if (error)
363 goto out;
364 inode = nd.dentry->d_inode;
365
366 error = -EROFS;
367 if (IS_RDONLY(inode))
368 goto dput_and_out;
369
370 /* Don't worry, the checks are done in inode_change_ok() */
371 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
372 if (times) {
373 error = -EPERM;
374 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
375 goto dput_and_out;
376
377 error = get_user(newattrs.ia_atime.tv_sec, &times->actime);
378 newattrs.ia_atime.tv_nsec = 0;
379 if (!error)
380 error = get_user(newattrs.ia_mtime.tv_sec, &times->modtime);
381 newattrs.ia_mtime.tv_nsec = 0;
382 if (error)
383 goto dput_and_out;
384
385 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
386 } else {
387 error = -EACCES;
388 if (IS_IMMUTABLE(inode))
389 goto dput_and_out;
390
391 if (current->fsuid != inode->i_uid &&
392 (error = permission(inode,MAY_WRITE,&nd)) != 0)
393 goto dput_and_out;
394 }
395 down(&inode->i_sem);
396 error = notify_change(nd.dentry, &newattrs);
397 up(&inode->i_sem);
398dput_and_out:
399 path_release(&nd);
400out:
401 return error;
402}
403
404#endif
405
406/* If times==NULL, set access and modification to current time,
407 * must be owner or have write permission.
408 * Else, update from *times, must be owner or super user.
409 */
410long do_utimes(char __user * filename, struct timeval * times)
411{
412 int error;
413 struct nameidata nd;
414 struct inode * inode;
415 struct iattr newattrs;
416
417 error = user_path_walk(filename, &nd);
418
419 if (error)
420 goto out;
421 inode = nd.dentry->d_inode;
422
423 error = -EROFS;
424 if (IS_RDONLY(inode))
425 goto dput_and_out;
426
427 /* Don't worry, the checks are done in inode_change_ok() */
428 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
429 if (times) {
430 error = -EPERM;
431 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
432 goto dput_and_out;
433
434 newattrs.ia_atime.tv_sec = times[0].tv_sec;
435 newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000;
436 newattrs.ia_mtime.tv_sec = times[1].tv_sec;
437 newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000;
438 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
439 } else {
440 error = -EACCES;
441 if (IS_IMMUTABLE(inode))
442 goto dput_and_out;
443
444 if (current->fsuid != inode->i_uid &&
445 (error = permission(inode,MAY_WRITE,&nd)) != 0)
446 goto dput_and_out;
447 }
448 down(&inode->i_sem);
449 error = notify_change(nd.dentry, &newattrs);
450 up(&inode->i_sem);
451dput_and_out:
452 path_release(&nd);
453out:
454 return error;
455}
456
457asmlinkage long sys_utimes(char __user * filename, struct timeval __user * utimes)
458{
459 struct timeval times[2];
460
461 if (utimes && copy_from_user(&times, utimes, sizeof(times)))
462 return -EFAULT;
463 return do_utimes(filename, utimes ? times : NULL);
464}
465
466
467/*
468 * access() needs to use the real uid/gid, not the effective uid/gid.
469 * We do this by temporarily clearing all FS-related capabilities and
470 * switching the fsuid/fsgid around to the real ones.
471 */
472asmlinkage long sys_access(const char __user * filename, int mode)
473{
474 struct nameidata nd;
475 int old_fsuid, old_fsgid;
476 kernel_cap_t old_cap;
477 int res;
478
479 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
480 return -EINVAL;
481
482 old_fsuid = current->fsuid;
483 old_fsgid = current->fsgid;
484 old_cap = current->cap_effective;
485
486 current->fsuid = current->uid;
487 current->fsgid = current->gid;
488
489 /*
490 * Clear the capabilities if we switch to a non-root user
491 *
492 * FIXME: There is a race here against sys_capset. The
493 * capabilities can change yet we will restore the old
494 * value below. We should hold task_capabilities_lock,
495 * but we cannot because user_path_walk can sleep.
496 */
497 if (current->uid)
498 cap_clear(current->cap_effective);
499 else
500 current->cap_effective = current->cap_permitted;
501
502 res = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd);
503 if (!res) {
504 res = permission(nd.dentry->d_inode, mode, &nd);
505 /* SuS v2 requires we report a read only fs too */
506 if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode)
507 && !special_file(nd.dentry->d_inode->i_mode))
508 res = -EROFS;
509 path_release(&nd);
510 }
511
512 current->fsuid = old_fsuid;
513 current->fsgid = old_fsgid;
514 current->cap_effective = old_cap;
515
516 return res;
517}
518
519asmlinkage long sys_chdir(const char __user * filename)
520{
521 struct nameidata nd;
522 int error;
523
524 error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd);
525 if (error)
526 goto out;
527
528 error = permission(nd.dentry->d_inode,MAY_EXEC,&nd);
529 if (error)
530 goto dput_and_out;
531
532 set_fs_pwd(current->fs, nd.mnt, nd.dentry);
533
534dput_and_out:
535 path_release(&nd);
536out:
537 return error;
538}
539
540asmlinkage long sys_fchdir(unsigned int fd)
541{
542 struct file *file;
543 struct dentry *dentry;
544 struct inode *inode;
545 struct vfsmount *mnt;
546 int error;
547
548 error = -EBADF;
549 file = fget(fd);
550 if (!file)
551 goto out;
552
553 dentry = file->f_dentry;
554 mnt = file->f_vfsmnt;
555 inode = dentry->d_inode;
556
557 error = -ENOTDIR;
558 if (!S_ISDIR(inode->i_mode))
559 goto out_putf;
560
561 error = permission(inode, MAY_EXEC, NULL);
562 if (!error)
563 set_fs_pwd(current->fs, mnt, dentry);
564out_putf:
565 fput(file);
566out:
567 return error;
568}
569
570asmlinkage long sys_chroot(const char __user * filename)
571{
572 struct nameidata nd;
573 int error;
574
575 error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd);
576 if (error)
577 goto out;
578
579 error = permission(nd.dentry->d_inode,MAY_EXEC,&nd);
580 if (error)
581 goto dput_and_out;
582
583 error = -EPERM;
584 if (!capable(CAP_SYS_CHROOT))
585 goto dput_and_out;
586
587 set_fs_root(current->fs, nd.mnt, nd.dentry);
588 set_fs_altroot();
589 error = 0;
590dput_and_out:
591 path_release(&nd);
592out:
593 return error;
594}
595
596asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
597{
598 struct inode * inode;
599 struct dentry * dentry;
600 struct file * file;
601 int err = -EBADF;
602 struct iattr newattrs;
603
604 file = fget(fd);
605 if (!file)
606 goto out;
607
608 dentry = file->f_dentry;
609 inode = dentry->d_inode;
610
611 err = -EROFS;
612 if (IS_RDONLY(inode))
613 goto out_putf;
614 err = -EPERM;
615 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
616 goto out_putf;
617 down(&inode->i_sem);
618 if (mode == (mode_t) -1)
619 mode = inode->i_mode;
620 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
621 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
622 err = notify_change(dentry, &newattrs);
623 up(&inode->i_sem);
624
625out_putf:
626 fput(file);
627out:
628 return err;
629}
630
631asmlinkage long sys_chmod(const char __user * filename, mode_t mode)
632{
633 struct nameidata nd;
634 struct inode * inode;
635 int error;
636 struct iattr newattrs;
637
638 error = user_path_walk(filename, &nd);
639 if (error)
640 goto out;
641 inode = nd.dentry->d_inode;
642
643 error = -EROFS;
644 if (IS_RDONLY(inode))
645 goto dput_and_out;
646
647 error = -EPERM;
648 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
649 goto dput_and_out;
650
651 down(&inode->i_sem);
652 if (mode == (mode_t) -1)
653 mode = inode->i_mode;
654 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
655 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
656 error = notify_change(nd.dentry, &newattrs);
657 up(&inode->i_sem);
658
659dput_and_out:
660 path_release(&nd);
661out:
662 return error;
663}
664
665static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
666{
667 struct inode * inode;
668 int error;
669 struct iattr newattrs;
670
671 error = -ENOENT;
672 if (!(inode = dentry->d_inode)) {
673 printk(KERN_ERR "chown_common: NULL inode\n");
674 goto out;
675 }
676 error = -EROFS;
677 if (IS_RDONLY(inode))
678 goto out;
679 error = -EPERM;
680 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
681 goto out;
682 newattrs.ia_valid = ATTR_CTIME;
683 if (user != (uid_t) -1) {
684 newattrs.ia_valid |= ATTR_UID;
685 newattrs.ia_uid = user;
686 }
687 if (group != (gid_t) -1) {
688 newattrs.ia_valid |= ATTR_GID;
689 newattrs.ia_gid = group;
690 }
691 if (!S_ISDIR(inode->i_mode))
692 newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID;
693 down(&inode->i_sem);
694 error = notify_change(dentry, &newattrs);
695 up(&inode->i_sem);
696out:
697 return error;
698}
699
700asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
701{
702 struct nameidata nd;
703 int error;
704
705 error = user_path_walk(filename, &nd);
706 if (!error) {
707 error = chown_common(nd.dentry, user, group);
708 path_release(&nd);
709 }
710 return error;
711}
712
713asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group)
714{
715 struct nameidata nd;
716 int error;
717
718 error = user_path_walk_link(filename, &nd);
719 if (!error) {
720 error = chown_common(nd.dentry, user, group);
721 path_release(&nd);
722 }
723 return error;
724}
725
726
727asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
728{
729 struct file * file;
730 int error = -EBADF;
731
732 file = fget(fd);
733 if (file) {
734 error = chown_common(file->f_dentry, user, group);
735 fput(file);
736 }
737 return error;
738}
739
740/*
741 * Note that while the flag value (low two bits) for sys_open means:
742 * 00 - read-only
743 * 01 - write-only
744 * 10 - read-write
745 * 11 - special
746 * it is changed into
747 * 00 - no permissions needed
748 * 01 - read-permission
749 * 10 - write-permission
750 * 11 - read-write
751 * for the internal routines (ie open_namei()/follow_link() etc). 00 is
752 * used by symlinks.
753 */
754struct file *filp_open(const char * filename, int flags, int mode)
755{
756 int namei_flags, error;
757 struct nameidata nd;
758
759 namei_flags = flags;
760 if ((namei_flags+1) & O_ACCMODE)
761 namei_flags++;
762 if (namei_flags & O_TRUNC)
763 namei_flags |= 2;
764
765 error = open_namei(filename, namei_flags, mode, &nd);
766 if (!error)
767 return dentry_open(nd.dentry, nd.mnt, flags);
768
769 return ERR_PTR(error);
770}
771
772EXPORT_SYMBOL(filp_open);
773
774struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
775{
776 struct file * f;
777 struct inode *inode;
778 int error;
779
780 error = -ENFILE;
781 f = get_empty_filp();
782 if (!f)
783 goto cleanup_dentry;
784 f->f_flags = flags;
785 f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
786 inode = dentry->d_inode;
787 if (f->f_mode & FMODE_WRITE) {
788 error = get_write_access(inode);
789 if (error)
790 goto cleanup_file;
791 }
792
793 f->f_mapping = inode->i_mapping;
794 f->f_dentry = dentry;
795 f->f_vfsmnt = mnt;
796 f->f_pos = 0;
797 f->f_op = fops_get(inode->i_fop);
798 file_move(f, &inode->i_sb->s_files);
799
800 if (f->f_op && f->f_op->open) {
801 error = f->f_op->open(inode,f);
802 if (error)
803 goto cleanup_all;
804 }
805 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
806
807 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
808
809 /* NB: we're sure to have correct a_ops only after f_op->open */
810 if (f->f_flags & O_DIRECT) {
811 if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) {
812 fput(f);
813 f = ERR_PTR(-EINVAL);
814 }
815 }
816
817 return f;
818
819cleanup_all:
820 fops_put(f->f_op);
821 if (f->f_mode & FMODE_WRITE)
822 put_write_access(inode);
823 file_kill(f);
824 f->f_dentry = NULL;
825 f->f_vfsmnt = NULL;
826cleanup_file:
827 put_filp(f);
828cleanup_dentry:
829 dput(dentry);
830 mntput(mnt);
831 return ERR_PTR(error);
832}
833
834EXPORT_SYMBOL(dentry_open);
835
836/*
837 * Find an empty file descriptor entry, and mark it busy.
838 */
839int get_unused_fd(void)
840{
841 struct files_struct * files = current->files;
842 int fd, error;
843
844 error = -EMFILE;
845 spin_lock(&files->file_lock);
846
847repeat:
848 fd = find_next_zero_bit(files->open_fds->fds_bits,
849 files->max_fdset,
850 files->next_fd);
851
852 /*
853 * N.B. For clone tasks sharing a files structure, this test
854 * will limit the total number of files that can be opened.
855 */
856 if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
857 goto out;
858
859 /* Do we need to expand the fd array or fd set? */
860 error = expand_files(files, fd);
861 if (error < 0)
862 goto out;
863
864 if (error) {
865 /*
866 * If we needed to expand the fs array we
867 * might have blocked - try again.
868 */
869 error = -EMFILE;
870 goto repeat;
871 }
872
873 FD_SET(fd, files->open_fds);
874 FD_CLR(fd, files->close_on_exec);
875 files->next_fd = fd + 1;
876#if 1
877 /* Sanity check */
878 if (files->fd[fd] != NULL) {
879 printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
880 files->fd[fd] = NULL;
881 }
882#endif
883 error = fd;
884
885out:
886 spin_unlock(&files->file_lock);
887 return error;
888}
889
890EXPORT_SYMBOL(get_unused_fd);
891
892static inline void __put_unused_fd(struct files_struct *files, unsigned int fd)
893{
894 __FD_CLR(fd, files->open_fds);
895 if (fd < files->next_fd)
896 files->next_fd = fd;
897}
898
899void fastcall put_unused_fd(unsigned int fd)
900{
901 struct files_struct *files = current->files;
902 spin_lock(&files->file_lock);
903 __put_unused_fd(files, fd);
904 spin_unlock(&files->file_lock);
905}
906
907EXPORT_SYMBOL(put_unused_fd);
908
909/*
910 * Install a file pointer in the fd array.
911 *
912 * The VFS is full of places where we drop the files lock between
913 * setting the open_fds bitmap and installing the file in the file
914 * array. At any such point, we are vulnerable to a dup2() race
915 * installing a file in the array before us. We need to detect this and
916 * fput() the struct file we are about to overwrite in this case.
917 *
918 * It should never happen - if we allow dup2() do it, _really_ bad things
919 * will follow.
920 */
921
922void fastcall fd_install(unsigned int fd, struct file * file)
923{
924 struct files_struct *files = current->files;
925 spin_lock(&files->file_lock);
926 if (unlikely(files->fd[fd] != NULL))
927 BUG();
928 files->fd[fd] = file;
929 spin_unlock(&files->file_lock);
930}
931
932EXPORT_SYMBOL(fd_install);
933
934asmlinkage long sys_open(const char __user * filename, int flags, int mode)
935{
936 char * tmp;
937 int fd, error;
938
Yoav Zachef3daed2005-06-23 00:09:58 -0700939 if (force_o_largefile())
940 flags |= O_LARGEFILE;
941
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 tmp = getname(filename);
943 fd = PTR_ERR(tmp);
944 if (!IS_ERR(tmp)) {
945 fd = get_unused_fd();
946 if (fd >= 0) {
947 struct file *f = filp_open(tmp, flags, mode);
948 error = PTR_ERR(f);
949 if (IS_ERR(f))
950 goto out_error;
951 fd_install(fd, f);
952 }
953out:
954 putname(tmp);
955 }
956 return fd;
957
958out_error:
959 put_unused_fd(fd);
960 fd = error;
961 goto out;
962}
963EXPORT_SYMBOL_GPL(sys_open);
964
965#ifndef __alpha__
966
967/*
968 * For backward compatibility? Maybe this should be moved
969 * into arch/i386 instead?
970 */
971asmlinkage long sys_creat(const char __user * pathname, int mode)
972{
973 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
974}
975
976#endif
977
978/*
979 * "id" is the POSIX thread ID. We use the
980 * files pointer for this..
981 */
982int filp_close(struct file *filp, fl_owner_t id)
983{
984 int retval;
985
986 /* Report and clear outstanding errors */
987 retval = filp->f_error;
988 if (retval)
989 filp->f_error = 0;
990
991 if (!file_count(filp)) {
992 printk(KERN_ERR "VFS: Close: file count is 0\n");
993 return retval;
994 }
995
996 if (filp->f_op && filp->f_op->flush) {
997 int err = filp->f_op->flush(filp);
998 if (!retval)
999 retval = err;
1000 }
1001
1002 dnotify_flush(filp, id);
1003 locks_remove_posix(filp, id);
1004 fput(filp);
1005 return retval;
1006}
1007
1008EXPORT_SYMBOL(filp_close);
1009
1010/*
1011 * Careful here! We test whether the file pointer is NULL before
1012 * releasing the fd. This ensures that one clone task can't release
1013 * an fd while another clone is opening it.
1014 */
1015asmlinkage long sys_close(unsigned int fd)
1016{
1017 struct file * filp;
1018 struct files_struct *files = current->files;
1019
1020 spin_lock(&files->file_lock);
1021 if (fd >= files->max_fds)
1022 goto out_unlock;
1023 filp = files->fd[fd];
1024 if (!filp)
1025 goto out_unlock;
1026 files->fd[fd] = NULL;
1027 FD_CLR(fd, files->close_on_exec);
1028 __put_unused_fd(files, fd);
1029 spin_unlock(&files->file_lock);
1030 return filp_close(filp, files);
1031
1032out_unlock:
1033 spin_unlock(&files->file_lock);
1034 return -EBADF;
1035}
1036
1037EXPORT_SYMBOL(sys_close);
1038
1039/*
1040 * This routine simulates a hangup on the tty, to arrange that users
1041 * are given clean terminals at login time.
1042 */
1043asmlinkage long sys_vhangup(void)
1044{
1045 if (capable(CAP_SYS_TTY_CONFIG)) {
1046 tty_vhangup(current->signal->tty);
1047 return 0;
1048 }
1049 return -EPERM;
1050}
1051
1052/*
1053 * Called when an inode is about to be open.
1054 * We use this to disallow opening large files on 32bit systems if
1055 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1056 * on this flag in sys_open.
1057 */
1058int generic_file_open(struct inode * inode, struct file * filp)
1059{
1060 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1061 return -EFBIG;
1062 return 0;
1063}
1064
1065EXPORT_SYMBOL(generic_file_open);
1066
1067/*
1068 * This is used by subsystems that don't want seekable
1069 * file descriptors
1070 */
1071int nonseekable_open(struct inode *inode, struct file *filp)
1072{
1073 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1074 return 0;
1075}
1076
1077EXPORT_SYMBOL(nonseekable_open);