Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/fs/open.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 23637 byte(s)
Tag kernel26-2.6.12-alx-r9
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/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> |
24 | #include <linux/pagemap.h> |
25 | #include <linux/syscalls.h> |
26 | |
27 | #include <asm/unistd.h> |
28 | |
29 | int vfs_statfs(struct super_block *sb, struct kstatfs *buf) |
30 | { |
31 | int retval = -ENODEV; |
32 | |
33 | if (sb) { |
34 | retval = -ENOSYS; |
35 | if (sb->s_op->statfs) { |
36 | memset(buf, 0, sizeof(*buf)); |
37 | retval = security_sb_statfs(sb); |
38 | if (retval) |
39 | return retval; |
40 | retval = sb->s_op->statfs(sb, buf); |
41 | if (retval == 0 && buf->f_frsize == 0) |
42 | buf->f_frsize = buf->f_bsize; |
43 | } |
44 | } |
45 | return retval; |
46 | } |
47 | |
48 | EXPORT_SYMBOL(vfs_statfs); |
49 | |
50 | static int vfs_statfs_native(struct super_block *sb, struct statfs *buf) |
51 | { |
52 | struct kstatfs st; |
53 | int retval; |
54 | |
55 | retval = vfs_statfs(sb, &st); |
56 | if (retval) |
57 | return retval; |
58 | |
59 | if (sizeof(*buf) == sizeof(st)) |
60 | memcpy(buf, &st, sizeof(st)); |
61 | else { |
62 | if (sizeof buf->f_blocks == 4) { |
63 | if ((st.f_blocks | st.f_bfree | st.f_bavail) & |
64 | 0xffffffff00000000ULL) |
65 | return -EOVERFLOW; |
66 | /* |
67 | * f_files and f_ffree may be -1; it's okay to stuff |
68 | * that into 32 bits |
69 | */ |
70 | if (st.f_files != -1 && |
71 | (st.f_files & 0xffffffff00000000ULL)) |
72 | return -EOVERFLOW; |
73 | if (st.f_ffree != -1 && |
74 | (st.f_ffree & 0xffffffff00000000ULL)) |
75 | return -EOVERFLOW; |
76 | } |
77 | |
78 | buf->f_type = st.f_type; |
79 | buf->f_bsize = st.f_bsize; |
80 | buf->f_blocks = st.f_blocks; |
81 | buf->f_bfree = st.f_bfree; |
82 | buf->f_bavail = st.f_bavail; |
83 | buf->f_files = st.f_files; |
84 | buf->f_ffree = st.f_ffree; |
85 | buf->f_fsid = st.f_fsid; |
86 | buf->f_namelen = st.f_namelen; |
87 | buf->f_frsize = st.f_frsize; |
88 | memset(buf->f_spare, 0, sizeof(buf->f_spare)); |
89 | } |
90 | return 0; |
91 | } |
92 | |
93 | static int vfs_statfs64(struct super_block *sb, struct statfs64 *buf) |
94 | { |
95 | struct kstatfs st; |
96 | int retval; |
97 | |
98 | retval = vfs_statfs(sb, &st); |
99 | if (retval) |
100 | return retval; |
101 | |
102 | if (sizeof(*buf) == sizeof(st)) |
103 | memcpy(buf, &st, sizeof(st)); |
104 | else { |
105 | buf->f_type = st.f_type; |
106 | buf->f_bsize = st.f_bsize; |
107 | buf->f_blocks = st.f_blocks; |
108 | buf->f_bfree = st.f_bfree; |
109 | buf->f_bavail = st.f_bavail; |
110 | buf->f_files = st.f_files; |
111 | buf->f_ffree = st.f_ffree; |
112 | buf->f_fsid = st.f_fsid; |
113 | buf->f_namelen = st.f_namelen; |
114 | buf->f_frsize = st.f_frsize; |
115 | memset(buf->f_spare, 0, sizeof(buf->f_spare)); |
116 | } |
117 | return 0; |
118 | } |
119 | |
120 | asmlinkage long sys_statfs(const char __user * path, struct statfs __user * buf) |
121 | { |
122 | struct nameidata nd; |
123 | int error; |
124 | |
125 | error = user_path_walk(path, &nd); |
126 | if (!error) { |
127 | struct statfs tmp; |
128 | error = vfs_statfs_native(nd.dentry->d_inode->i_sb, &tmp); |
129 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) |
130 | error = -EFAULT; |
131 | path_release(&nd); |
132 | } |
133 | return error; |
134 | } |
135 | |
136 | |
137 | asmlinkage long sys_statfs64(const char __user *path, size_t sz, struct statfs64 __user *buf) |
138 | { |
139 | struct nameidata nd; |
140 | long error; |
141 | |
142 | if (sz != sizeof(*buf)) |
143 | return -EINVAL; |
144 | error = user_path_walk(path, &nd); |
145 | if (!error) { |
146 | struct statfs64 tmp; |
147 | error = vfs_statfs64(nd.dentry->d_inode->i_sb, &tmp); |
148 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) |
149 | error = -EFAULT; |
150 | path_release(&nd); |
151 | } |
152 | return error; |
153 | } |
154 | |
155 | |
156 | asmlinkage long sys_fstatfs(unsigned int fd, struct statfs __user * buf) |
157 | { |
158 | struct file * file; |
159 | struct statfs tmp; |
160 | int error; |
161 | |
162 | error = -EBADF; |
163 | file = fget(fd); |
164 | if (!file) |
165 | goto out; |
166 | error = vfs_statfs_native(file->f_dentry->d_inode->i_sb, &tmp); |
167 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) |
168 | error = -EFAULT; |
169 | fput(file); |
170 | out: |
171 | return error; |
172 | } |
173 | |
174 | asmlinkage long sys_fstatfs64(unsigned int fd, size_t sz, struct statfs64 __user *buf) |
175 | { |
176 | struct file * file; |
177 | struct statfs64 tmp; |
178 | int error; |
179 | |
180 | if (sz != sizeof(*buf)) |
181 | return -EINVAL; |
182 | |
183 | error = -EBADF; |
184 | file = fget(fd); |
185 | if (!file) |
186 | goto out; |
187 | error = vfs_statfs64(file->f_dentry->d_inode->i_sb, &tmp); |
188 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) |
189 | error = -EFAULT; |
190 | fput(file); |
191 | out: |
192 | return error; |
193 | } |
194 | |
195 | int do_truncate(struct dentry *dentry, loff_t length) |
196 | { |
197 | int err; |
198 | struct iattr newattrs; |
199 | |
200 | /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ |
201 | if (length < 0) |
202 | return -EINVAL; |
203 | |
204 | newattrs.ia_size = length; |
205 | newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; |
206 | |
207 | down(&dentry->d_inode->i_sem); |
208 | err = notify_change(dentry, &newattrs); |
209 | up(&dentry->d_inode->i_sem); |
210 | return err; |
211 | } |
212 | |
213 | static inline long do_sys_truncate(const char __user * path, loff_t length) |
214 | { |
215 | struct nameidata nd; |
216 | struct inode * inode; |
217 | int error; |
218 | |
219 | error = -EINVAL; |
220 | if (length < 0) /* sorry, but loff_t says... */ |
221 | goto out; |
222 | |
223 | error = user_path_walk(path, &nd); |
224 | if (error) |
225 | goto out; |
226 | inode = nd.dentry->d_inode; |
227 | |
228 | /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ |
229 | error = -EISDIR; |
230 | if (S_ISDIR(inode->i_mode)) |
231 | goto dput_and_out; |
232 | |
233 | error = -EINVAL; |
234 | if (!S_ISREG(inode->i_mode)) |
235 | goto dput_and_out; |
236 | |
237 | error = permission(inode,MAY_WRITE,&nd); |
238 | if (error) |
239 | goto dput_and_out; |
240 | |
241 | error = -EROFS; |
242 | if (IS_RDONLY(inode)) |
243 | goto dput_and_out; |
244 | |
245 | error = -EPERM; |
246 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
247 | goto dput_and_out; |
248 | |
249 | /* |
250 | * Make sure that there are no leases. |
251 | */ |
252 | error = break_lease(inode, FMODE_WRITE); |
253 | if (error) |
254 | goto dput_and_out; |
255 | |
256 | error = get_write_access(inode); |
257 | if (error) |
258 | goto dput_and_out; |
259 | |
260 | error = locks_verify_truncate(inode, NULL, length); |
261 | if (!error) { |
262 | DQUOT_INIT(inode); |
263 | error = do_truncate(nd.dentry, length); |
264 | } |
265 | put_write_access(inode); |
266 | |
267 | dput_and_out: |
268 | path_release(&nd); |
269 | out: |
270 | return error; |
271 | } |
272 | |
273 | asmlinkage long sys_truncate(const char __user * path, unsigned long length) |
274 | { |
275 | /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */ |
276 | return do_sys_truncate(path, (long)length); |
277 | } |
278 | |
279 | static inline long do_sys_ftruncate(unsigned int fd, loff_t length, int small) |
280 | { |
281 | struct inode * inode; |
282 | struct dentry *dentry; |
283 | struct file * file; |
284 | int error; |
285 | |
286 | error = -EINVAL; |
287 | if (length < 0) |
288 | goto out; |
289 | error = -EBADF; |
290 | file = fget(fd); |
291 | if (!file) |
292 | goto out; |
293 | |
294 | /* explicitly opened as large or we are on 64-bit box */ |
295 | if (file->f_flags & O_LARGEFILE) |
296 | small = 0; |
297 | |
298 | dentry = file->f_dentry; |
299 | inode = dentry->d_inode; |
300 | error = -EINVAL; |
301 | if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) |
302 | goto out_putf; |
303 | |
304 | error = -EINVAL; |
305 | /* Cannot ftruncate over 2^31 bytes without large file support */ |
306 | if (small && length > MAX_NON_LFS) |
307 | goto out_putf; |
308 | |
309 | error = -EPERM; |
310 | if (IS_APPEND(inode)) |
311 | goto out_putf; |
312 | |
313 | error = locks_verify_truncate(inode, file, length); |
314 | if (!error) |
315 | error = do_truncate(dentry, length); |
316 | out_putf: |
317 | fput(file); |
318 | out: |
319 | return error; |
320 | } |
321 | |
322 | asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length) |
323 | { |
324 | return do_sys_ftruncate(fd, length, 1); |
325 | } |
326 | |
327 | /* LFS versions of truncate are only needed on 32 bit machines */ |
328 | #if BITS_PER_LONG == 32 |
329 | asmlinkage long sys_truncate64(const char __user * path, loff_t length) |
330 | { |
331 | return do_sys_truncate(path, length); |
332 | } |
333 | |
334 | asmlinkage long sys_ftruncate64(unsigned int fd, loff_t length) |
335 | { |
336 | return do_sys_ftruncate(fd, length, 0); |
337 | } |
338 | #endif |
339 | |
340 | #ifdef __ARCH_WANT_SYS_UTIME |
341 | |
342 | /* |
343 | * sys_utime() can be implemented in user-level using sys_utimes(). |
344 | * Is this for backwards compatibility? If so, why not move it |
345 | * into the appropriate arch directory (for those architectures that |
346 | * need it). |
347 | */ |
348 | |
349 | /* If times==NULL, set access and modification to current time, |
350 | * must be owner or have write permission. |
351 | * Else, update from *times, must be owner or super user. |
352 | */ |
353 | asmlinkage long sys_utime(char __user * filename, struct utimbuf __user * times) |
354 | { |
355 | int error; |
356 | struct nameidata nd; |
357 | struct inode * inode; |
358 | struct iattr newattrs; |
359 | |
360 | error = user_path_walk(filename, &nd); |
361 | if (error) |
362 | goto out; |
363 | inode = nd.dentry->d_inode; |
364 | |
365 | error = -EROFS; |
366 | if (IS_RDONLY(inode)) |
367 | goto dput_and_out; |
368 | |
369 | /* Don't worry, the checks are done in inode_change_ok() */ |
370 | newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; |
371 | if (times) { |
372 | error = -EPERM; |
373 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) |
374 | goto dput_and_out; |
375 | |
376 | error = get_user(newattrs.ia_atime.tv_sec, ×->actime); |
377 | newattrs.ia_atime.tv_nsec = 0; |
378 | if (!error) |
379 | error = get_user(newattrs.ia_mtime.tv_sec, ×->modtime); |
380 | newattrs.ia_mtime.tv_nsec = 0; |
381 | if (error) |
382 | goto dput_and_out; |
383 | |
384 | newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; |
385 | } else { |
386 | error = -EACCES; |
387 | if (IS_IMMUTABLE(inode)) |
388 | goto dput_and_out; |
389 | |
390 | if (current->fsuid != inode->i_uid && |
391 | (error = permission(inode,MAY_WRITE,&nd)) != 0) |
392 | goto dput_and_out; |
393 | } |
394 | down(&inode->i_sem); |
395 | error = notify_change(nd.dentry, &newattrs); |
396 | up(&inode->i_sem); |
397 | dput_and_out: |
398 | path_release(&nd); |
399 | out: |
400 | return error; |
401 | } |
402 | |
403 | #endif |
404 | |
405 | /* If times==NULL, set access and modification to current time, |
406 | * must be owner or have write permission. |
407 | * Else, update from *times, must be owner or super user. |
408 | */ |
409 | long do_utimes(char __user * filename, struct timeval * times) |
410 | { |
411 | int error; |
412 | struct nameidata nd; |
413 | struct inode * inode; |
414 | struct iattr newattrs; |
415 | |
416 | error = user_path_walk(filename, &nd); |
417 | |
418 | if (error) |
419 | goto out; |
420 | inode = nd.dentry->d_inode; |
421 | |
422 | error = -EROFS; |
423 | if (IS_RDONLY(inode)) |
424 | goto dput_and_out; |
425 | |
426 | /* Don't worry, the checks are done in inode_change_ok() */ |
427 | newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; |
428 | if (times) { |
429 | error = -EPERM; |
430 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) |
431 | goto dput_and_out; |
432 | |
433 | newattrs.ia_atime.tv_sec = times[0].tv_sec; |
434 | newattrs.ia_atime.tv_nsec = times[0].tv_usec * 1000; |
435 | newattrs.ia_mtime.tv_sec = times[1].tv_sec; |
436 | newattrs.ia_mtime.tv_nsec = times[1].tv_usec * 1000; |
437 | newattrs.ia_valid |= ATTR_ATIME_SET | ATTR_MTIME_SET; |
438 | } else { |
439 | error = -EACCES; |
440 | if (IS_IMMUTABLE(inode)) |
441 | goto dput_and_out; |
442 | |
443 | if (current->fsuid != inode->i_uid && |
444 | (error = permission(inode,MAY_WRITE,&nd)) != 0) |
445 | goto dput_and_out; |
446 | } |
447 | down(&inode->i_sem); |
448 | error = notify_change(nd.dentry, &newattrs); |
449 | up(&inode->i_sem); |
450 | dput_and_out: |
451 | path_release(&nd); |
452 | out: |
453 | return error; |
454 | } |
455 | |
456 | asmlinkage long sys_utimes(char __user * filename, struct timeval __user * utimes) |
457 | { |
458 | struct timeval times[2]; |
459 | |
460 | if (utimes && copy_from_user(×, utimes, sizeof(times))) |
461 | return -EFAULT; |
462 | return do_utimes(filename, utimes ? times : NULL); |
463 | } |
464 | |
465 | |
466 | /* |
467 | * access() needs to use the real uid/gid, not the effective uid/gid. |
468 | * We do this by temporarily clearing all FS-related capabilities and |
469 | * switching the fsuid/fsgid around to the real ones. |
470 | */ |
471 | asmlinkage long sys_access(const char __user * filename, int mode) |
472 | { |
473 | struct nameidata nd; |
474 | int old_fsuid, old_fsgid; |
475 | kernel_cap_t old_cap; |
476 | int res; |
477 | |
478 | if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ |
479 | return -EINVAL; |
480 | |
481 | old_fsuid = current->fsuid; |
482 | old_fsgid = current->fsgid; |
483 | old_cap = current->cap_effective; |
484 | |
485 | current->fsuid = current->uid; |
486 | current->fsgid = current->gid; |
487 | |
488 | /* |
489 | * Clear the capabilities if we switch to a non-root user |
490 | * |
491 | * FIXME: There is a race here against sys_capset. The |
492 | * capabilities can change yet we will restore the old |
493 | * value below. We should hold task_capabilities_lock, |
494 | * but we cannot because user_path_walk can sleep. |
495 | */ |
496 | if (current->uid) |
497 | cap_clear(current->cap_effective); |
498 | else |
499 | current->cap_effective = current->cap_permitted; |
500 | |
501 | res = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd); |
502 | if (!res) { |
503 | res = permission(nd.dentry->d_inode, mode, &nd); |
504 | /* SuS v2 requires we report a read only fs too */ |
505 | if(!res && (mode & S_IWOTH) && IS_RDONLY(nd.dentry->d_inode) |
506 | && !special_file(nd.dentry->d_inode->i_mode)) |
507 | res = -EROFS; |
508 | path_release(&nd); |
509 | } |
510 | |
511 | current->fsuid = old_fsuid; |
512 | current->fsgid = old_fsgid; |
513 | current->cap_effective = old_cap; |
514 | |
515 | return res; |
516 | } |
517 | |
518 | asmlinkage long sys_chdir(const char __user * filename) |
519 | { |
520 | struct nameidata nd; |
521 | int error; |
522 | |
523 | error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd); |
524 | if (error) |
525 | goto out; |
526 | |
527 | error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); |
528 | if (error) |
529 | goto dput_and_out; |
530 | |
531 | set_fs_pwd(current->fs, nd.mnt, nd.dentry); |
532 | |
533 | dput_and_out: |
534 | path_release(&nd); |
535 | out: |
536 | return error; |
537 | } |
538 | |
539 | asmlinkage long sys_fchdir(unsigned int fd) |
540 | { |
541 | struct file *file; |
542 | struct dentry *dentry; |
543 | struct inode *inode; |
544 | struct vfsmount *mnt; |
545 | int error; |
546 | |
547 | error = -EBADF; |
548 | file = fget(fd); |
549 | if (!file) |
550 | goto out; |
551 | |
552 | dentry = file->f_dentry; |
553 | mnt = file->f_vfsmnt; |
554 | inode = dentry->d_inode; |
555 | |
556 | error = -ENOTDIR; |
557 | if (!S_ISDIR(inode->i_mode)) |
558 | goto out_putf; |
559 | |
560 | error = permission(inode, MAY_EXEC, NULL); |
561 | if (!error) |
562 | set_fs_pwd(current->fs, mnt, dentry); |
563 | out_putf: |
564 | fput(file); |
565 | out: |
566 | return error; |
567 | } |
568 | |
569 | asmlinkage long sys_chroot(const char __user * filename) |
570 | { |
571 | struct nameidata nd; |
572 | int error; |
573 | |
574 | error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd); |
575 | if (error) |
576 | goto out; |
577 | |
578 | error = permission(nd.dentry->d_inode,MAY_EXEC,&nd); |
579 | if (error) |
580 | goto dput_and_out; |
581 | |
582 | error = -EPERM; |
583 | if (!capable(CAP_SYS_CHROOT)) |
584 | goto dput_and_out; |
585 | |
586 | set_fs_root(current->fs, nd.mnt, nd.dentry); |
587 | set_fs_altroot(); |
588 | error = 0; |
589 | dput_and_out: |
590 | path_release(&nd); |
591 | out: |
592 | return error; |
593 | } |
594 | |
595 | asmlinkage long sys_fchmod(unsigned int fd, mode_t mode) |
596 | { |
597 | struct inode * inode; |
598 | struct dentry * dentry; |
599 | struct file * file; |
600 | int err = -EBADF; |
601 | struct iattr newattrs; |
602 | |
603 | file = fget(fd); |
604 | if (!file) |
605 | goto out; |
606 | |
607 | dentry = file->f_dentry; |
608 | inode = dentry->d_inode; |
609 | |
610 | err = -EROFS; |
611 | if (IS_RDONLY(inode)) |
612 | goto out_putf; |
613 | err = -EPERM; |
614 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
615 | goto out_putf; |
616 | down(&inode->i_sem); |
617 | if (mode == (mode_t) -1) |
618 | mode = inode->i_mode; |
619 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); |
620 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; |
621 | err = notify_change(dentry, &newattrs); |
622 | up(&inode->i_sem); |
623 | |
624 | out_putf: |
625 | fput(file); |
626 | out: |
627 | return err; |
628 | } |
629 | |
630 | asmlinkage long sys_chmod(const char __user * filename, mode_t mode) |
631 | { |
632 | struct nameidata nd; |
633 | struct inode * inode; |
634 | int error; |
635 | struct iattr newattrs; |
636 | |
637 | error = user_path_walk(filename, &nd); |
638 | if (error) |
639 | goto out; |
640 | inode = nd.dentry->d_inode; |
641 | |
642 | error = -EROFS; |
643 | if (IS_RDONLY(inode)) |
644 | goto dput_and_out; |
645 | |
646 | error = -EPERM; |
647 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
648 | goto dput_and_out; |
649 | |
650 | down(&inode->i_sem); |
651 | if (mode == (mode_t) -1) |
652 | mode = inode->i_mode; |
653 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); |
654 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; |
655 | error = notify_change(nd.dentry, &newattrs); |
656 | up(&inode->i_sem); |
657 | |
658 | dput_and_out: |
659 | path_release(&nd); |
660 | out: |
661 | return error; |
662 | } |
663 | |
664 | static int chown_common(struct dentry * dentry, uid_t user, gid_t group) |
665 | { |
666 | struct inode * inode; |
667 | int error; |
668 | struct iattr newattrs; |
669 | |
670 | error = -ENOENT; |
671 | if (!(inode = dentry->d_inode)) { |
672 | printk(KERN_ERR "chown_common: NULL inode\n"); |
673 | goto out; |
674 | } |
675 | error = -EROFS; |
676 | if (IS_RDONLY(inode)) |
677 | goto out; |
678 | error = -EPERM; |
679 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
680 | goto out; |
681 | newattrs.ia_valid = ATTR_CTIME; |
682 | if (user != (uid_t) -1) { |
683 | newattrs.ia_valid |= ATTR_UID; |
684 | newattrs.ia_uid = user; |
685 | } |
686 | if (group != (gid_t) -1) { |
687 | newattrs.ia_valid |= ATTR_GID; |
688 | newattrs.ia_gid = group; |
689 | } |
690 | if (!S_ISDIR(inode->i_mode)) |
691 | newattrs.ia_valid |= ATTR_KILL_SUID|ATTR_KILL_SGID; |
692 | down(&inode->i_sem); |
693 | error = notify_change(dentry, &newattrs); |
694 | up(&inode->i_sem); |
695 | out: |
696 | return error; |
697 | } |
698 | |
699 | asmlinkage long sys_chown(const char __user * filename, uid_t user, gid_t group) |
700 | { |
701 | struct nameidata nd; |
702 | int error; |
703 | |
704 | error = user_path_walk(filename, &nd); |
705 | if (!error) { |
706 | error = chown_common(nd.dentry, user, group); |
707 | path_release(&nd); |
708 | } |
709 | return error; |
710 | } |
711 | |
712 | asmlinkage long sys_lchown(const char __user * filename, uid_t user, gid_t group) |
713 | { |
714 | struct nameidata nd; |
715 | int error; |
716 | |
717 | error = user_path_walk_link(filename, &nd); |
718 | if (!error) { |
719 | error = chown_common(nd.dentry, user, group); |
720 | path_release(&nd); |
721 | } |
722 | return error; |
723 | } |
724 | |
725 | |
726 | asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group) |
727 | { |
728 | struct file * file; |
729 | int error = -EBADF; |
730 | |
731 | file = fget(fd); |
732 | if (file) { |
733 | error = chown_common(file->f_dentry, user, group); |
734 | fput(file); |
735 | } |
736 | return error; |
737 | } |
738 | |
739 | /* |
740 | * Note that while the flag value (low two bits) for sys_open means: |
741 | * 00 - read-only |
742 | * 01 - write-only |
743 | * 10 - read-write |
744 | * 11 - special |
745 | * it is changed into |
746 | * 00 - no permissions needed |
747 | * 01 - read-permission |
748 | * 10 - write-permission |
749 | * 11 - read-write |
750 | * for the internal routines (ie open_namei()/follow_link() etc). 00 is |
751 | * used by symlinks. |
752 | */ |
753 | struct file *filp_open(const char * filename, int flags, int mode) |
754 | { |
755 | int namei_flags, error; |
756 | struct nameidata nd; |
757 | |
758 | namei_flags = flags; |
759 | if ((namei_flags+1) & O_ACCMODE) |
760 | namei_flags++; |
761 | if (namei_flags & O_TRUNC) |
762 | namei_flags |= 2; |
763 | |
764 | error = open_namei(filename, namei_flags, mode, &nd); |
765 | if (!error) |
766 | return dentry_open(nd.dentry, nd.mnt, flags); |
767 | |
768 | return ERR_PTR(error); |
769 | } |
770 | |
771 | EXPORT_SYMBOL(filp_open); |
772 | |
773 | struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags) |
774 | { |
775 | struct file * f; |
776 | struct inode *inode; |
777 | int error; |
778 | |
779 | error = -ENFILE; |
780 | f = get_empty_filp(); |
781 | if (!f) |
782 | goto cleanup_dentry; |
783 | f->f_flags = flags; |
784 | f->f_mode = ((flags+1) & O_ACCMODE) | FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; |
785 | inode = dentry->d_inode; |
786 | if (f->f_mode & FMODE_WRITE) { |
787 | error = get_write_access(inode); |
788 | if (error) |
789 | goto cleanup_file; |
790 | } |
791 | |
792 | f->f_mapping = inode->i_mapping; |
793 | f->f_dentry = dentry; |
794 | f->f_vfsmnt = mnt; |
795 | f->f_pos = 0; |
796 | f->f_op = fops_get(inode->i_fop); |
797 | file_move(f, &inode->i_sb->s_files); |
798 | |
799 | if (f->f_op && f->f_op->open) { |
800 | error = f->f_op->open(inode,f); |
801 | if (error) |
802 | goto cleanup_all; |
803 | } |
804 | f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); |
805 | |
806 | file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); |
807 | |
808 | /* NB: we're sure to have correct a_ops only after f_op->open */ |
809 | if (f->f_flags & O_DIRECT) { |
810 | if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) { |
811 | fput(f); |
812 | f = ERR_PTR(-EINVAL); |
813 | } |
814 | } |
815 | |
816 | return f; |
817 | |
818 | cleanup_all: |
819 | fops_put(f->f_op); |
820 | if (f->f_mode & FMODE_WRITE) |
821 | put_write_access(inode); |
822 | file_kill(f); |
823 | f->f_dentry = NULL; |
824 | f->f_vfsmnt = NULL; |
825 | cleanup_file: |
826 | put_filp(f); |
827 | cleanup_dentry: |
828 | dput(dentry); |
829 | mntput(mnt); |
830 | return ERR_PTR(error); |
831 | } |
832 | |
833 | EXPORT_SYMBOL(dentry_open); |
834 | |
835 | /* |
836 | * Find an empty file descriptor entry, and mark it busy. |
837 | */ |
838 | int get_unused_fd(void) |
839 | { |
840 | struct files_struct * files = current->files; |
841 | int fd, error; |
842 | |
843 | error = -EMFILE; |
844 | spin_lock(&files->file_lock); |
845 | |
846 | repeat: |
847 | fd = find_next_zero_bit(files->open_fds->fds_bits, |
848 | files->max_fdset, |
849 | files->next_fd); |
850 | |
851 | /* |
852 | * N.B. For clone tasks sharing a files structure, this test |
853 | * will limit the total number of files that can be opened. |
854 | */ |
855 | if (fd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
856 | goto out; |
857 | |
858 | /* Do we need to expand the fd array or fd set? */ |
859 | error = expand_files(files, fd); |
860 | if (error < 0) |
861 | goto out; |
862 | |
863 | if (error) { |
864 | /* |
865 | * If we needed to expand the fs array we |
866 | * might have blocked - try again. |
867 | */ |
868 | error = -EMFILE; |
869 | goto repeat; |
870 | } |
871 | |
872 | FD_SET(fd, files->open_fds); |
873 | FD_CLR(fd, files->close_on_exec); |
874 | files->next_fd = fd + 1; |
875 | #if 1 |
876 | /* Sanity check */ |
877 | if (files->fd[fd] != NULL) { |
878 | printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd); |
879 | files->fd[fd] = NULL; |
880 | } |
881 | #endif |
882 | error = fd; |
883 | |
884 | out: |
885 | spin_unlock(&files->file_lock); |
886 | return error; |
887 | } |
888 | |
889 | EXPORT_SYMBOL(get_unused_fd); |
890 | |
891 | static inline void __put_unused_fd(struct files_struct *files, unsigned int fd) |
892 | { |
893 | __FD_CLR(fd, files->open_fds); |
894 | if (fd < files->next_fd) |
895 | files->next_fd = fd; |
896 | } |
897 | |
898 | void fastcall put_unused_fd(unsigned int fd) |
899 | { |
900 | struct files_struct *files = current->files; |
901 | spin_lock(&files->file_lock); |
902 | __put_unused_fd(files, fd); |
903 | spin_unlock(&files->file_lock); |
904 | } |
905 | |
906 | EXPORT_SYMBOL(put_unused_fd); |
907 | |
908 | /* |
909 | * Install a file pointer in the fd array. |
910 | * |
911 | * The VFS is full of places where we drop the files lock between |
912 | * setting the open_fds bitmap and installing the file in the file |
913 | * array. At any such point, we are vulnerable to a dup2() race |
914 | * installing a file in the array before us. We need to detect this and |
915 | * fput() the struct file we are about to overwrite in this case. |
916 | * |
917 | * It should never happen - if we allow dup2() do it, _really_ bad things |
918 | * will follow. |
919 | */ |
920 | |
921 | void fastcall fd_install(unsigned int fd, struct file * file) |
922 | { |
923 | struct files_struct *files = current->files; |
924 | spin_lock(&files->file_lock); |
925 | if (unlikely(files->fd[fd] != NULL)) |
926 | BUG(); |
927 | files->fd[fd] = file; |
928 | spin_unlock(&files->file_lock); |
929 | } |
930 | |
931 | EXPORT_SYMBOL(fd_install); |
932 | |
933 | asmlinkage long sys_open(const char __user * filename, int flags, int mode) |
934 | { |
935 | char * tmp; |
936 | int fd, error; |
937 | |
938 | #if BITS_PER_LONG != 32 |
939 | flags |= O_LARGEFILE; |
940 | #endif |
941 | tmp = getname(filename); |
942 | fd = PTR_ERR(tmp); |
943 | if (!IS_ERR(tmp)) { |
944 | fd = get_unused_fd(); |
945 | if (fd >= 0) { |
946 | struct file *f = filp_open(tmp, flags, mode); |
947 | error = PTR_ERR(f); |
948 | if (IS_ERR(f)) |
949 | goto out_error; |
950 | fd_install(fd, f); |
951 | } |
952 | out: |
953 | putname(tmp); |
954 | } |
955 | return fd; |
956 | |
957 | out_error: |
958 | put_unused_fd(fd); |
959 | fd = error; |
960 | goto out; |
961 | } |
962 | EXPORT_SYMBOL_GPL(sys_open); |
963 | |
964 | #ifndef __alpha__ |
965 | |
966 | /* |
967 | * For backward compatibility? Maybe this should be moved |
968 | * into arch/i386 instead? |
969 | */ |
970 | asmlinkage long sys_creat(const char __user * pathname, int mode) |
971 | { |
972 | return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); |
973 | } |
974 | |
975 | #endif |
976 | |
977 | /* |
978 | * "id" is the POSIX thread ID. We use the |
979 | * files pointer for this.. |
980 | */ |
981 | int filp_close(struct file *filp, fl_owner_t id) |
982 | { |
983 | int retval; |
984 | |
985 | /* Report and clear outstanding errors */ |
986 | retval = filp->f_error; |
987 | if (retval) |
988 | filp->f_error = 0; |
989 | |
990 | if (!file_count(filp)) { |
991 | printk(KERN_ERR "VFS: Close: file count is 0\n"); |
992 | return retval; |
993 | } |
994 | |
995 | if (filp->f_op && filp->f_op->flush) { |
996 | int err = filp->f_op->flush(filp); |
997 | if (!retval) |
998 | retval = err; |
999 | } |
1000 | |
1001 | dnotify_flush(filp, id); |
1002 | locks_remove_posix(filp, id); |
1003 | fput(filp); |
1004 | return retval; |
1005 | } |
1006 | |
1007 | EXPORT_SYMBOL(filp_close); |
1008 | |
1009 | /* |
1010 | * Careful here! We test whether the file pointer is NULL before |
1011 | * releasing the fd. This ensures that one clone task can't release |
1012 | * an fd while another clone is opening it. |
1013 | */ |
1014 | asmlinkage long sys_close(unsigned int fd) |
1015 | { |
1016 | struct file * filp; |
1017 | struct files_struct *files = current->files; |
1018 | |
1019 | spin_lock(&files->file_lock); |
1020 | if (fd >= files->max_fds) |
1021 | goto out_unlock; |
1022 | filp = files->fd[fd]; |
1023 | if (!filp) |
1024 | goto out_unlock; |
1025 | files->fd[fd] = NULL; |
1026 | FD_CLR(fd, files->close_on_exec); |
1027 | __put_unused_fd(files, fd); |
1028 | spin_unlock(&files->file_lock); |
1029 | return filp_close(filp, files); |
1030 | |
1031 | out_unlock: |
1032 | spin_unlock(&files->file_lock); |
1033 | return -EBADF; |
1034 | } |
1035 | |
1036 | EXPORT_SYMBOL(sys_close); |
1037 | |
1038 | /* |
1039 | * This routine simulates a hangup on the tty, to arrange that users |
1040 | * are given clean terminals at login time. |
1041 | */ |
1042 | asmlinkage long sys_vhangup(void) |
1043 | { |
1044 | if (capable(CAP_SYS_TTY_CONFIG)) { |
1045 | tty_vhangup(current->signal->tty); |
1046 | return 0; |
1047 | } |
1048 | return -EPERM; |
1049 | } |
1050 | |
1051 | /* |
1052 | * Called when an inode is about to be open. |
1053 | * We use this to disallow opening large files on 32bit systems if |
1054 | * the caller didn't specify O_LARGEFILE. On 64bit systems we force |
1055 | * on this flag in sys_open. |
1056 | */ |
1057 | int generic_file_open(struct inode * inode, struct file * filp) |
1058 | { |
1059 | if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) |
1060 | return -EFBIG; |
1061 | return 0; |
1062 | } |
1063 | |
1064 | EXPORT_SYMBOL(generic_file_open); |
1065 | |
1066 | /* |
1067 | * This is used by subsystems that don't want seekable |
1068 | * file descriptors |
1069 | */ |
1070 | int nonseekable_open(struct inode *inode, struct file *filp) |
1071 | { |
1072 | filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); |
1073 | return 0; |
1074 | } |
1075 | |
1076 | EXPORT_SYMBOL(nonseekable_open); |