blob: 75f3329e8a67885036e06ee76e570073cb5e106f [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
NeilBrown4a301312006-01-08 01:02:39 -0800197int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
198 struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199{
200 int err;
201 struct iattr newattrs;
202
203 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
204 if (length < 0)
205 return -EINVAL;
206
207 newattrs.ia_size = length;
NeilBrown4a301312006-01-08 01:02:39 -0800208 newattrs.ia_valid = ATTR_SIZE | time_attrs;
Miklos Szeredicc4e69d2005-11-07 00:59:49 -0800209 if (filp) {
210 newattrs.ia_file = filp;
211 newattrs.ia_valid |= ATTR_FILE;
212 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
214 down(&dentry->d_inode->i_sem);
215 err = notify_change(dentry, &newattrs);
216 up(&dentry->d_inode->i_sem);
217 return err;
218}
219
Matt Mackallb01ec0e2006-01-08 01:05:20 -0800220static long do_sys_truncate(const char __user * path, loff_t length)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221{
222 struct nameidata nd;
223 struct inode * inode;
224 int error;
225
226 error = -EINVAL;
227 if (length < 0) /* sorry, but loff_t says... */
228 goto out;
229
230 error = user_path_walk(path, &nd);
231 if (error)
232 goto out;
233 inode = nd.dentry->d_inode;
234
235 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
236 error = -EISDIR;
237 if (S_ISDIR(inode->i_mode))
238 goto dput_and_out;
239
240 error = -EINVAL;
241 if (!S_ISREG(inode->i_mode))
242 goto dput_and_out;
243
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800244 error = vfs_permission(&nd, MAY_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 if (error)
246 goto dput_and_out;
247
248 error = -EROFS;
249 if (IS_RDONLY(inode))
250 goto dput_and_out;
251
252 error = -EPERM;
253 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
254 goto dput_and_out;
255
256 /*
257 * Make sure that there are no leases.
258 */
259 error = break_lease(inode, FMODE_WRITE);
260 if (error)
261 goto dput_and_out;
262
263 error = get_write_access(inode);
264 if (error)
265 goto dput_and_out;
266
267 error = locks_verify_truncate(inode, NULL, length);
268 if (!error) {
269 DQUOT_INIT(inode);
NeilBrown4a301312006-01-08 01:02:39 -0800270 error = do_truncate(nd.dentry, length, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 }
272 put_write_access(inode);
273
274dput_and_out:
275 path_release(&nd);
276out:
277 return error;
278}
279
280asmlinkage long sys_truncate(const char __user * path, unsigned long length)
281{
282 /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
283 return do_sys_truncate(path, (long)length);
284}
285
Matt Mackallb01ec0e2006-01-08 01:05:20 -0800286static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287{
288 struct inode * inode;
289 struct dentry *dentry;
290 struct file * file;
291 int error;
292
293 error = -EINVAL;
294 if (length < 0)
295 goto out;
296 error = -EBADF;
297 file = fget(fd);
298 if (!file)
299 goto out;
300
301 /* explicitly opened as large or we are on 64-bit box */
302 if (file->f_flags & O_LARGEFILE)
303 small = 0;
304
305 dentry = file->f_dentry;
306 inode = dentry->d_inode;
307 error = -EINVAL;
308 if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
309 goto out_putf;
310
311 error = -EINVAL;
312 /* Cannot ftruncate over 2^31 bytes without large file support */
313 if (small && length > MAX_NON_LFS)
314 goto out_putf;
315
316 error = -EPERM;
317 if (IS_APPEND(inode))
318 goto out_putf;
319
320 error = locks_verify_truncate(inode, file, length);
321 if (!error)
NeilBrown4a301312006-01-08 01:02:39 -0800322 error = do_truncate(dentry, length, 0, file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323out_putf:
324 fput(file);
325out:
326 return error;
327}
328
329asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length)
330{
331 return do_sys_ftruncate(fd, length, 1);
332}
333
334/* LFS versions of truncate are only needed on 32 bit machines */
335#if BITS_PER_LONG == 32
336asmlinkage long sys_truncate64(const char __user * path, loff_t length)
337{
338 return do_sys_truncate(path, length);
339}
340
341asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length)
342{
343 return do_sys_ftruncate(fd, length, 0);
344}
345#endif
346
347#ifdef __ARCH_WANT_SYS_UTIME
348
349/*
350 * sys_utime() can be implemented in user-level using sys_utimes().
351 * Is this for backwards compatibility? If so, why not move it
352 * into the appropriate arch directory (for those architectures that
353 * need it).
354 */
355
356/* If times==NULL, set access and modification to current time,
357 * must be owner or have write permission.
358 * Else, update from *times, must be owner or super user.
359 */
360asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times)
361{
362 int error;
363 struct nameidata nd;
364 struct inode * inode;
365 struct iattr newattrs;
366
367 error = user_path_walk(filename, &nd);
368 if (error)
369 goto out;
370 inode = nd.dentry->d_inode;
371
372 error = -EROFS;
373 if (IS_RDONLY(inode))
374 goto dput_and_out;
375
376 /* Don't worry, the checks are done in inode_change_ok() */
377 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
378 if (times) {
379 error = -EPERM;
380 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
381 goto dput_and_out;
382
383 error = get_user(newattrs.ia_atime.tv_sec, &times->actime);
384 newattrs.ia_atime.tv_nsec = 0;
385 if (!error)
386 error = get_user(newattrs.ia_mtime.tv_sec, &times->modtime);
387 newattrs.ia_mtime.tv_nsec = 0;
388 if (error)
389 goto dput_and_out;
390
391 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
392 } else {
393 error = -EACCES;
394 if (IS_IMMUTABLE(inode))
395 goto dput_and_out;
396
397 if (current->fsuid != inode->i_uid &&
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800398 (error = vfs_permission(&nd, MAY_WRITE)) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 goto dput_and_out;
400 }
401 down(&inode->i_sem);
402 error = notify_change(nd.dentry, &newattrs);
403 up(&inode->i_sem);
404dput_and_out:
405 path_release(&nd);
406out:
407 return error;
408}
409
410#endif
411
412/* If times==NULL, set access and modification to current time,
413 * must be owner or have write permission.
414 * Else, update from *times, must be owner or super user.
415 */
416long do_utimes(char __user * filename, struct timeval * times)
417{
418 int error;
419 struct nameidata nd;
420 struct inode * inode;
421 struct iattr newattrs;
422
423 error = user_path_walk(filename, &nd);
424
425 if (error)
426 goto out;
427 inode = nd.dentry->d_inode;
428
429 error = -EROFS;
430 if (IS_RDONLY(inode))
431 goto dput_and_out;
432
433 /* Don't worry, the checks are done in inode_change_ok() */
434 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
435 if (times) {
436 error = -EPERM;
437 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
438 goto dput_and_out;
439
440 newattrs.ia_atime.tv_sec = times[0].tv_sec;
441 newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000;
442 newattrs.ia_mtime.tv_sec = times[1].tv_sec;
443 newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000;
444 newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET;
445 } else {
446 error = -EACCES;
447 if (IS_IMMUTABLE(inode))
448 goto dput_and_out;
449
450 if (current->fsuid != inode->i_uid &&
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800451 (error = vfs_permission(&nd, MAY_WRITE)) != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 goto dput_and_out;
453 }
454 down(&inode->i_sem);
455 error = notify_change(nd.dentry, &newattrs);
456 up(&inode->i_sem);
457dput_and_out:
458 path_release(&nd);
459out:
460 return error;
461}
462
463asmlinkage long sys_utimes(char __user * filename, struct timeval __user * utimes)
464{
465 struct timeval times[2];
466
467 if (utimes && copy_from_user(&times, utimes, sizeof(times)))
468 return -EFAULT;
469 return do_utimes(filename, utimes ? times : NULL);
470}
471
472
473/*
474 * access() needs to use the real uid/gid, not the effective uid/gid.
475 * We do this by temporarily clearing all FS-related capabilities and
476 * switching the fsuid/fsgid around to the real ones.
477 */
478asmlinkage long sys_access(const char __user * filename, int mode)
479{
480 struct nameidata nd;
481 int old_fsuid, old_fsgid;
482 kernel_cap_t old_cap;
483 int res;
484
485 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
486 return -EINVAL;
487
488 old_fsuid = current->fsuid;
489 old_fsgid = current->fsgid;
490 old_cap = current->cap_effective;
491
492 current->fsuid = current->uid;
493 current->fsgid = current->gid;
494
495 /*
496 * Clear the capabilities if we switch to a non-root user
497 *
498 * FIXME: There is a race here against sys_capset. The
499 * capabilities can change yet we will restore the old
500 * value below. We should hold task_capabilities_lock,
501 * but we cannot because user_path_walk can sleep.
502 */
503 if (current->uid)
504 cap_clear(current->cap_effective);
505 else
506 current->cap_effective = current->cap_permitted;
507
508 res = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd);
509 if (!res) {
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800510 res = vfs_permission(&nd, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 /* SuS v2 requires we report a read only fs too */
512 if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode)
513 && !special_file(nd.dentry->d_inode->i_mode))
514 res = -EROFS;
515 path_release(&nd);
516 }
517
518 current->fsuid = old_fsuid;
519 current->fsgid = old_fsgid;
520 current->cap_effective = old_cap;
521
522 return res;
523}
524
525asmlinkage long sys_chdir(const char __user * filename)
526{
527 struct nameidata nd;
528 int error;
529
530 error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd);
531 if (error)
532 goto out;
533
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800534 error = vfs_permission(&nd, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 if (error)
536 goto dput_and_out;
537
538 set_fs_pwd(current->fs, nd.mnt, nd.dentry);
539
540dput_and_out:
541 path_release(&nd);
542out:
543 return error;
544}
545
546asmlinkage long sys_fchdir(unsigned int fd)
547{
548 struct file *file;
549 struct dentry *dentry;
550 struct inode *inode;
551 struct vfsmount *mnt;
552 int error;
553
554 error = -EBADF;
555 file = fget(fd);
556 if (!file)
557 goto out;
558
559 dentry = file->f_dentry;
560 mnt = file->f_vfsmnt;
561 inode = dentry->d_inode;
562
563 error = -ENOTDIR;
564 if (!S_ISDIR(inode->i_mode))
565 goto out_putf;
566
Christoph Hellwig8c744fb2005-11-08 21:35:04 -0800567 error = file_permission(file, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 if (!error)
569 set_fs_pwd(current->fs, mnt, dentry);
570out_putf:
571 fput(file);
572out:
573 return error;
574}
575
576asmlinkage long sys_chroot(const char __user * filename)
577{
578 struct nameidata nd;
579 int error;
580
581 error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd);
582 if (error)
583 goto out;
584
Christoph Hellwige4543ed2005-11-08 21:35:04 -0800585 error = vfs_permission(&nd, MAY_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 if (error)
587 goto dput_and_out;
588
589 error = -EPERM;
590 if (!capable(CAP_SYS_CHROOT))
591 goto dput_and_out;
592
593 set_fs_root(current->fs, nd.mnt, nd.dentry);
594 set_fs_altroot();
595 error = 0;
596dput_and_out:
597 path_release(&nd);
598out:
599 return error;
600}
601
602asmlinkage long sys_fchmod(unsigned int fd, mode_t mode)
603{
604 struct inode * inode;
605 struct dentry * dentry;
606 struct file * file;
607 int err = -EBADF;
608 struct iattr newattrs;
609
610 file = fget(fd);
611 if (!file)
612 goto out;
613
614 dentry = file->f_dentry;
615 inode = dentry->d_inode;
616
617 err = -EROFS;
618 if (IS_RDONLY(inode))
619 goto out_putf;
620 err = -EPERM;
621 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
622 goto out_putf;
623 down(&inode->i_sem);
624 if (mode == (mode_t) -1)
625 mode = inode->i_mode;
626 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
627 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
628 err = notify_change(dentry, &newattrs);
629 up(&inode->i_sem);
630
631out_putf:
632 fput(file);
633out:
634 return err;
635}
636
637asmlinkage long sys_chmod(const char __user * filename, mode_t mode)
638{
639 struct nameidata nd;
640 struct inode * inode;
641 int error;
642 struct iattr newattrs;
643
644 error = user_path_walk(filename, &nd);
645 if (error)
646 goto out;
647 inode = nd.dentry->d_inode;
648
649 error = -EROFS;
650 if (IS_RDONLY(inode))
651 goto dput_and_out;
652
653 error = -EPERM;
654 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
655 goto dput_and_out;
656
657 down(&inode->i_sem);
658 if (mode == (mode_t) -1)
659 mode = inode->i_mode;
660 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
661 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
662 error = notify_change(nd.dentry, &newattrs);
663 up(&inode->i_sem);
664
665dput_and_out:
666 path_release(&nd);
667out:
668 return error;
669}
670
671static int chown_common(struct dentry * dentry, uid_t user, gid_t group)
672{
673 struct inode * inode;
674 int error;
675 struct iattr newattrs;
676
677 error = -ENOENT;
678 if (!(inode = dentry->d_inode)) {
679 printk(KERN_ERR "chown_common: NULL inode\n");
680 goto out;
681 }
682 error = -EROFS;
683 if (IS_RDONLY(inode))
684 goto out;
685 error = -EPERM;
686 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
687 goto out;
688 newattrs.ia_valid = ATTR_CTIME;
689 if (user != (uid_t) -1) {
690 newattrs.ia_valid |= ATTR_UID;
691 newattrs.ia_uid = user;
692 }
693 if (group != (gid_t) -1) {
694 newattrs.ia_valid |= ATTR_GID;
695 newattrs.ia_gid = group;
696 }
697 if (!S_ISDIR(inode->i_mode))
698 newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID;
699 down(&inode->i_sem);
700 error = notify_change(dentry, &newattrs);
701 up(&inode->i_sem);
702out:
703 return error;
704}
705
706asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group)
707{
708 struct nameidata nd;
709 int error;
710
711 error = user_path_walk(filename, &nd);
712 if (!error) {
713 error = chown_common(nd.dentry, user, group);
714 path_release(&nd);
715 }
716 return error;
717}
718
719asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group)
720{
721 struct nameidata nd;
722 int error;
723
724 error = user_path_walk_link(filename, &nd);
725 if (!error) {
726 error = chown_common(nd.dentry, user, group);
727 path_release(&nd);
728 }
729 return error;
730}
731
732
733asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group)
734{
735 struct file * file;
736 int error = -EBADF;
737
738 file = fget(fd);
739 if (file) {
740 error = chown_common(file->f_dentry, user, group);
741 fput(file);
742 }
743 return error;
744}
745
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700746static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
Trond Myklebust834f2a42005-10-18 14:20:16 -0700747 int flags, struct file *f,
748 int (*open)(struct inode *, struct file *))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 struct inode *inode;
751 int error;
752
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 f->f_flags = flags;
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700754 f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK |
755 FMODE_PREAD | FMODE_PWRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756 inode = dentry->d_inode;
757 if (f->f_mode & FMODE_WRITE) {
758 error = get_write_access(inode);
759 if (error)
760 goto cleanup_file;
761 }
762
763 f->f_mapping = inode->i_mapping;
764 f->f_dentry = dentry;
765 f->f_vfsmnt = mnt;
766 f->f_pos = 0;
767 f->f_op = fops_get(inode->i_fop);
768 file_move(f, &inode->i_sb->s_files);
769
Trond Myklebust834f2a42005-10-18 14:20:16 -0700770 if (!open && f->f_op)
771 open = f->f_op->open;
772 if (open) {
773 error = open(inode, f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 if (error)
775 goto cleanup_all;
776 }
Trond Myklebust834f2a42005-10-18 14:20:16 -0700777
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
779
780 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
781
782 /* NB: we're sure to have correct a_ops only after f_op->open */
783 if (f->f_flags & O_DIRECT) {
Carsten Otteceffc072005-06-23 22:05:25 -0700784 if (!f->f_mapping->a_ops ||
785 ((!f->f_mapping->a_ops->direct_IO) &&
786 (!f->f_mapping->a_ops->get_xip_page))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 fput(f);
788 f = ERR_PTR(-EINVAL);
789 }
790 }
791
792 return f;
793
794cleanup_all:
795 fops_put(f->f_op);
796 if (f->f_mode & FMODE_WRITE)
797 put_write_access(inode);
798 file_kill(f);
799 f->f_dentry = NULL;
800 f->f_vfsmnt = NULL;
801cleanup_file:
802 put_filp(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 dput(dentry);
804 mntput(mnt);
805 return ERR_PTR(error);
806}
807
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700808/*
809 * Note that while the flag value (low two bits) for sys_open means:
810 * 00 - read-only
811 * 01 - write-only
812 * 10 - read-write
813 * 11 - special
814 * it is changed into
815 * 00 - no permissions needed
816 * 01 - read-permission
817 * 10 - write-permission
818 * 11 - read-write
819 * for the internal routines (ie open_namei()/follow_link() etc). 00 is
820 * used by symlinks.
821 */
822struct file *filp_open(const char * filename, int flags, int mode)
823{
824 int namei_flags, error;
825 struct nameidata nd;
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700826
827 namei_flags = flags;
828 if ((namei_flags+1) & O_ACCMODE)
829 namei_flags++;
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700830
831 error = open_namei(filename, namei_flags, mode, &nd);
832 if (!error)
Trond Myklebust834f2a42005-10-18 14:20:16 -0700833 return nameidata_to_filp(&nd, flags);
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700834
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700835 return ERR_PTR(error);
836}
837EXPORT_SYMBOL(filp_open);
838
Trond Myklebust834f2a42005-10-18 14:20:16 -0700839/**
840 * lookup_instantiate_filp - instantiates the open intent filp
841 * @nd: pointer to nameidata
842 * @dentry: pointer to dentry
843 * @open: open callback
844 *
845 * Helper for filesystems that want to use lookup open intents and pass back
846 * a fully instantiated struct file to the caller.
847 * This function is meant to be called from within a filesystem's
848 * lookup method.
849 * Note that in case of error, nd->intent.open.file is destroyed, but the
850 * path information remains valid.
851 * If the open callback is set to NULL, then the standard f_op->open()
852 * filesystem callback is substituted.
853 */
854struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
855 int (*open)(struct inode *, struct file *))
856{
857 if (IS_ERR(nd->intent.open.file))
858 goto out;
859 if (IS_ERR(dentry))
860 goto out_err;
861 nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->mnt),
862 nd->intent.open.flags - 1,
863 nd->intent.open.file,
864 open);
865out:
866 return nd->intent.open.file;
867out_err:
868 release_open_intent(nd);
869 nd->intent.open.file = (struct file *)dentry;
870 goto out;
871}
872EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
873
874/**
875 * nameidata_to_filp - convert a nameidata to an open filp.
876 * @nd: pointer to nameidata
877 * @flags: open flags
878 *
879 * Note that this function destroys the original nameidata
880 */
881struct file *nameidata_to_filp(struct nameidata *nd, int flags)
882{
883 struct file *filp;
884
885 /* Pick up the filp from the open intent */
886 filp = nd->intent.open.file;
887 /* Has the filesystem initialised the file for us? */
888 if (filp->f_dentry == NULL)
889 filp = __dentry_open(nd->dentry, nd->mnt, flags, filp, NULL);
890 else
891 path_release(nd);
892 return filp;
893}
894
Peter Staubach6fdcc212005-11-07 00:59:42 -0800895/*
896 * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
897 * error.
898 */
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700899struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
900{
901 int error;
902 struct file *f;
903
904 error = -ENFILE;
905 f = get_empty_filp();
Peter Staubach6fdcc212005-11-07 00:59:42 -0800906 if (f == NULL) {
907 dput(dentry);
908 mntput(mnt);
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700909 return ERR_PTR(error);
Peter Staubach6fdcc212005-11-07 00:59:42 -0800910 }
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700911
Trond Myklebust834f2a42005-10-18 14:20:16 -0700912 return __dentry_open(dentry, mnt, flags, f, NULL);
Peter Staubacha1a5b3d2005-09-13 01:25:12 -0700913}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914EXPORT_SYMBOL(dentry_open);
915
916/*
917 * Find an empty file descriptor entry, and mark it busy.
918 */
919int get_unused_fd(void)
920{
921 struct files_struct * files = current->files;
922 int fd, error;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700923 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924
925 error = -EMFILE;
926 spin_lock(&files->file_lock);
927
928repeat:
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700929 fdt = files_fdtable(files);
930 fd = find_next_zero_bit(fdt->open_fds->fds_bits,
931 fdt->max_fdset,
932 fdt->next_fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933
934 /*
935 * N.B. For clone tasks sharing a files structure, this test
936 * will limit the total number of files that can be opened.
937 */
938 if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
939 goto out;
940
941 /* Do we need to expand the fd array or fd set? */
942 error = expand_files(files, fd);
943 if (error < 0)
944 goto out;
945
946 if (error) {
947 /*
948 * If we needed to expand the fs array we
949 * might have blocked - try again.
950 */
951 error = -EMFILE;
952 goto repeat;
953 }
954
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700955 FD_SET(fd, fdt->open_fds);
956 FD_CLR(fd, fdt->close_on_exec);
957 fdt->next_fd = fd + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958#if 1
959 /* Sanity check */
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700960 if (fdt->fd[fd] != NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700962 fdt->fd[fd] = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 }
964#endif
965 error = fd;
966
967out:
968 spin_unlock(&files->file_lock);
969 return error;
970}
971
972EXPORT_SYMBOL(get_unused_fd);
973
Matt Mackallb01ec0e2006-01-08 01:05:20 -0800974static void __put_unused_fd(struct files_struct *files, unsigned int fd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975{
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700976 struct fdtable *fdt = files_fdtable(files);
977 __FD_CLR(fd, fdt->open_fds);
978 if (fd < fdt->next_fd)
979 fdt->next_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980}
981
982void fastcall put_unused_fd(unsigned int fd)
983{
984 struct files_struct *files = current->files;
985 spin_lock(&files->file_lock);
986 __put_unused_fd(files, fd);
987 spin_unlock(&files->file_lock);
988}
989
990EXPORT_SYMBOL(put_unused_fd);
991
992/*
993 * Install a file pointer in the fd array.
994 *
995 * The VFS is full of places where we drop the files lock between
996 * setting the open_fds bitmap and installing the file in the file
997 * array. At any such point, we are vulnerable to a dup2() race
998 * installing a file in the array before us. We need to detect this and
999 * fput() the struct file we are about to overwrite in this case.
1000 *
1001 * It should never happen - if we allow dup2() do it, _really_ bad things
1002 * will follow.
1003 */
1004
1005void fastcall fd_install(unsigned int fd, struct file * file)
1006{
1007 struct files_struct *files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001008 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 spin_lock(&files->file_lock);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001010 fdt = files_fdtable(files);
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -07001011 BUG_ON(fdt->fd[fd] != NULL);
1012 rcu_assign_pointer(fdt->fd[fd], file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 spin_unlock(&files->file_lock);
1014}
1015
1016EXPORT_SYMBOL(fd_install);
1017
Miklos Szeredie922efc2005-09-06 15:18:25 -07001018long do_sys_open(const char __user *filename, int flags, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019{
Miklos Szeredie922efc2005-09-06 15:18:25 -07001020 char *tmp = getname(filename);
1021 int fd = PTR_ERR(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023 if (!IS_ERR(tmp)) {
1024 fd = get_unused_fd();
1025 if (fd >= 0) {
1026 struct file *f = filp_open(tmp, flags, mode);
Telemaque Ndizihiwefed2fc12005-06-23 00:10:33 -07001027 if (IS_ERR(f)) {
1028 put_unused_fd(fd);
1029 fd = PTR_ERR(f);
1030 } else {
Robert Love0eeca282005-07-12 17:06:03 -04001031 fsnotify_open(f->f_dentry);
Telemaque Ndizihiwefed2fc12005-06-23 00:10:33 -07001032 fd_install(fd, f);
1033 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 putname(tmp);
1036 }
1037 return fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038}
Miklos Szeredie922efc2005-09-06 15:18:25 -07001039
1040asmlinkage long sys_open(const char __user *filename, int flags, int mode)
1041{
1042 if (force_o_largefile())
1043 flags |= O_LARGEFILE;
1044
1045 return do_sys_open(filename, flags, mode);
1046}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047EXPORT_SYMBOL_GPL(sys_open);
1048
1049#ifndef __alpha__
1050
1051/*
1052 * For backward compatibility? Maybe this should be moved
1053 * into arch/i386 instead?
1054 */
1055asmlinkage long sys_creat(const char __user * pathname, int mode)
1056{
1057 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1058}
1059
1060#endif
1061
1062/*
1063 * "id" is the POSIX thread ID. We use the
1064 * files pointer for this..
1065 */
1066int filp_close(struct file *filp, fl_owner_t id)
1067{
Christoph Lameter45778ca2005-06-23 00:10:17 -07001068 int retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069
1070 if (!file_count(filp)) {
1071 printk(KERN_ERR "VFS: Close: file count is 0\n");
Christoph Lameter45778ca2005-06-23 00:10:17 -07001072 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 }
1074
Christoph Lameter45778ca2005-06-23 00:10:17 -07001075 if (filp->f_op && filp->f_op->flush)
1076 retval = filp->f_op->flush(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077
1078 dnotify_flush(filp, id);
1079 locks_remove_posix(filp, id);
1080 fput(filp);
1081 return retval;
1082}
1083
1084EXPORT_SYMBOL(filp_close);
1085
1086/*
1087 * Careful here! We test whether the file pointer is NULL before
1088 * releasing the fd. This ensures that one clone task can't release
1089 * an fd while another clone is opening it.
1090 */
1091asmlinkage long sys_close(unsigned int fd)
1092{
1093 struct file * filp;
1094 struct files_struct *files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001095 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096
1097 spin_lock(&files->file_lock);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001098 fdt = files_fdtable(files);
1099 if (fd >= fdt->max_fds)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100 goto out_unlock;
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001101 filp = fdt->fd[fd];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 if (!filp)
1103 goto out_unlock;
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -07001104 rcu_assign_pointer(fdt->fd[fd], NULL);
Dipankar Sarmabadf1662005-09-09 13:04:10 -07001105 FD_CLR(fd, fdt->close_on_exec);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 __put_unused_fd(files, fd);
1107 spin_unlock(&files->file_lock);
1108 return filp_close(filp, files);
1109
1110out_unlock:
1111 spin_unlock(&files->file_lock);
1112 return -EBADF;
1113}
1114
1115EXPORT_SYMBOL(sys_close);
1116
1117/*
1118 * This routine simulates a hangup on the tty, to arrange that users
1119 * are given clean terminals at login time.
1120 */
1121asmlinkage long sys_vhangup(void)
1122{
1123 if (capable(CAP_SYS_TTY_CONFIG)) {
1124 tty_vhangup(current->signal->tty);
1125 return 0;
1126 }
1127 return -EPERM;
1128}
1129
1130/*
1131 * Called when an inode is about to be open.
1132 * We use this to disallow opening large files on 32bit systems if
1133 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1134 * on this flag in sys_open.
1135 */
1136int generic_file_open(struct inode * inode, struct file * filp)
1137{
1138 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1139 return -EFBIG;
1140 return 0;
1141}
1142
1143EXPORT_SYMBOL(generic_file_open);
1144
1145/*
1146 * This is used by subsystems that don't want seekable
1147 * file descriptors
1148 */
1149int nonseekable_open(struct inode *inode, struct file *filp)
1150{
1151 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1152 return 0;
1153}
1154
1155EXPORT_SYMBOL(nonseekable_open);