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1 | /* |
2 | File: fs/xattr.c |
3 | |
4 | Extended attribute handling. |
5 | |
6 | Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org> |
7 | Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com> |
8 | Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> |
9 | */ |
10 | #include <linux/fs.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/file.h> |
13 | #include <linux/xattr.h> |
14 | #include <linux/mount.h> |
15 | #include <linux/namei.h> |
16 | #include <linux/security.h> |
17 | #include <linux/evm.h> |
18 | #include <linux/syscalls.h> |
19 | #include <linux/module.h> |
20 | #include <linux/fsnotify.h> |
21 | #include <linux/audit.h> |
22 | #include <asm/uaccess.h> |
23 | |
24 | |
25 | /* |
26 | * Check permissions for extended attribute access. This is a bit complicated |
27 | * because different namespaces have very different rules. |
28 | */ |
29 | static int |
30 | xattr_permission(struct inode *inode, const char *name, int mask) |
31 | { |
32 | /* |
33 | * We can never set or remove an extended attribute on a read-only |
34 | * filesystem or on an immutable / append-only inode. |
35 | */ |
36 | if (mask & MAY_WRITE) { |
37 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
38 | return -EPERM; |
39 | } |
40 | |
41 | /* |
42 | * No restriction for security.* and system.* from the VFS. Decision |
43 | * on these is left to the underlying filesystem / security module. |
44 | */ |
45 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || |
46 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
47 | return 0; |
48 | |
49 | /* |
50 | * The trusted.* namespace can only be accessed by privileged users. |
51 | */ |
52 | if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { |
53 | if (!capable(CAP_SYS_ADMIN)) |
54 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
55 | return 0; |
56 | } |
57 | |
58 | /* |
59 | * In the user.* namespace, only regular files and directories can have |
60 | * extended attributes. For sticky directories, only the owner and |
61 | * privileged users can write attributes. |
62 | */ |
63 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
64 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
65 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
66 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
67 | (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) |
68 | return -EPERM; |
69 | } |
70 | |
71 | return inode_permission(inode, mask); |
72 | } |
73 | |
74 | /** |
75 | * __vfs_setxattr_noperm - perform setxattr operation without performing |
76 | * permission checks. |
77 | * |
78 | * @dentry - object to perform setxattr on |
79 | * @name - xattr name to set |
80 | * @value - value to set @name to |
81 | * @size - size of @value |
82 | * @flags - flags to pass into filesystem operations |
83 | * |
84 | * returns the result of the internal setxattr or setsecurity operations. |
85 | * |
86 | * This function requires the caller to lock the inode's i_mutex before it |
87 | * is executed. It also assumes that the caller will make the appropriate |
88 | * permission checks. |
89 | */ |
90 | int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, |
91 | const void *value, size_t size, int flags) |
92 | { |
93 | struct inode *inode = dentry->d_inode; |
94 | int error = -EOPNOTSUPP; |
95 | int issec = !strncmp(name, XATTR_SECURITY_PREFIX, |
96 | XATTR_SECURITY_PREFIX_LEN); |
97 | |
98 | if (issec) |
99 | inode->i_flags &= ~S_NOSEC; |
100 | if (inode->i_op->setxattr) { |
101 | error = inode->i_op->setxattr(dentry, name, value, size, flags); |
102 | if (!error) { |
103 | fsnotify_xattr(dentry); |
104 | security_inode_post_setxattr(dentry, name, value, |
105 | size, flags); |
106 | } |
107 | } else if (issec) { |
108 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
109 | error = security_inode_setsecurity(inode, suffix, value, |
110 | size, flags); |
111 | if (!error) |
112 | fsnotify_xattr(dentry); |
113 | } |
114 | |
115 | return error; |
116 | } |
117 | |
118 | |
119 | int |
120 | vfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
121 | size_t size, int flags) |
122 | { |
123 | struct inode *inode = dentry->d_inode; |
124 | int error; |
125 | |
126 | error = xattr_permission(inode, name, MAY_WRITE); |
127 | if (error) |
128 | return error; |
129 | |
130 | mutex_lock(&inode->i_mutex); |
131 | error = security_inode_setxattr(dentry, name, value, size, flags); |
132 | if (error) |
133 | goto out; |
134 | |
135 | error = __vfs_setxattr_noperm(dentry, name, value, size, flags); |
136 | |
137 | out: |
138 | mutex_unlock(&inode->i_mutex); |
139 | return error; |
140 | } |
141 | EXPORT_SYMBOL_GPL(vfs_setxattr); |
142 | |
143 | ssize_t |
144 | xattr_getsecurity(struct inode *inode, const char *name, void *value, |
145 | size_t size) |
146 | { |
147 | void *buffer = NULL; |
148 | ssize_t len; |
149 | |
150 | if (!value || !size) { |
151 | len = security_inode_getsecurity(inode, name, &buffer, false); |
152 | goto out_noalloc; |
153 | } |
154 | |
155 | len = security_inode_getsecurity(inode, name, &buffer, true); |
156 | if (len < 0) |
157 | return len; |
158 | if (size < len) { |
159 | len = -ERANGE; |
160 | goto out; |
161 | } |
162 | memcpy(value, buffer, len); |
163 | out: |
164 | security_release_secctx(buffer, len); |
165 | out_noalloc: |
166 | return len; |
167 | } |
168 | EXPORT_SYMBOL_GPL(xattr_getsecurity); |
169 | |
170 | /* |
171 | * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr |
172 | * |
173 | * Allocate memory, if not already allocated, or re-allocate correct size, |
174 | * before retrieving the extended attribute. |
175 | * |
176 | * Returns the result of alloc, if failed, or the getxattr operation. |
177 | */ |
178 | ssize_t |
179 | vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, |
180 | size_t xattr_size, gfp_t flags) |
181 | { |
182 | struct inode *inode = dentry->d_inode; |
183 | char *value = *xattr_value; |
184 | int error; |
185 | |
186 | error = xattr_permission(inode, name, MAY_READ); |
187 | if (error) |
188 | return error; |
189 | |
190 | if (!inode->i_op->getxattr) |
191 | return -EOPNOTSUPP; |
192 | |
193 | error = inode->i_op->getxattr(dentry, name, NULL, 0); |
194 | if (error < 0) |
195 | return error; |
196 | |
197 | if (!value || (error > xattr_size)) { |
198 | value = krealloc(*xattr_value, error + 1, flags); |
199 | if (!value) |
200 | return -ENOMEM; |
201 | memset(value, 0, error + 1); |
202 | } |
203 | |
204 | error = inode->i_op->getxattr(dentry, name, value, error); |
205 | *xattr_value = value; |
206 | return error; |
207 | } |
208 | |
209 | /* Compare an extended attribute value with the given value */ |
210 | int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name, |
211 | const char *value, size_t size, gfp_t flags) |
212 | { |
213 | char *xattr_value = NULL; |
214 | int rc; |
215 | |
216 | rc = vfs_getxattr_alloc(dentry, xattr_name, &xattr_value, 0, flags); |
217 | if (rc < 0) |
218 | return rc; |
219 | |
220 | if ((rc != size) || (memcmp(xattr_value, value, rc) != 0)) |
221 | rc = -EINVAL; |
222 | else |
223 | rc = 0; |
224 | kfree(xattr_value); |
225 | return rc; |
226 | } |
227 | |
228 | ssize_t |
229 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
230 | { |
231 | struct inode *inode = dentry->d_inode; |
232 | int error; |
233 | |
234 | error = xattr_permission(inode, name, MAY_READ); |
235 | if (error) |
236 | return error; |
237 | |
238 | error = security_inode_getxattr(dentry, name); |
239 | if (error) |
240 | return error; |
241 | |
242 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
243 | XATTR_SECURITY_PREFIX_LEN)) { |
244 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
245 | int ret = xattr_getsecurity(inode, suffix, value, size); |
246 | /* |
247 | * Only overwrite the return value if a security module |
248 | * is actually active. |
249 | */ |
250 | if (ret == -EOPNOTSUPP) |
251 | goto nolsm; |
252 | return ret; |
253 | } |
254 | nolsm: |
255 | if (inode->i_op->getxattr) |
256 | error = inode->i_op->getxattr(dentry, name, value, size); |
257 | else |
258 | error = -EOPNOTSUPP; |
259 | |
260 | return error; |
261 | } |
262 | EXPORT_SYMBOL_GPL(vfs_getxattr); |
263 | |
264 | ssize_t |
265 | vfs_listxattr(struct dentry *d, char *list, size_t size) |
266 | { |
267 | ssize_t error; |
268 | |
269 | error = security_inode_listxattr(d); |
270 | if (error) |
271 | return error; |
272 | error = -EOPNOTSUPP; |
273 | if (d->d_inode->i_op->listxattr) { |
274 | error = d->d_inode->i_op->listxattr(d, list, size); |
275 | } else { |
276 | error = security_inode_listsecurity(d->d_inode, list, size); |
277 | if (size && error > size) |
278 | error = -ERANGE; |
279 | } |
280 | return error; |
281 | } |
282 | EXPORT_SYMBOL_GPL(vfs_listxattr); |
283 | |
284 | int |
285 | vfs_removexattr(struct dentry *dentry, const char *name) |
286 | { |
287 | struct inode *inode = dentry->d_inode; |
288 | int error; |
289 | |
290 | if (!inode->i_op->removexattr) |
291 | return -EOPNOTSUPP; |
292 | |
293 | error = xattr_permission(inode, name, MAY_WRITE); |
294 | if (error) |
295 | return error; |
296 | |
297 | error = security_inode_removexattr(dentry, name); |
298 | if (error) |
299 | return error; |
300 | |
301 | mutex_lock(&inode->i_mutex); |
302 | error = inode->i_op->removexattr(dentry, name); |
303 | mutex_unlock(&inode->i_mutex); |
304 | |
305 | if (!error) { |
306 | fsnotify_xattr(dentry); |
307 | evm_inode_post_removexattr(dentry, name); |
308 | } |
309 | return error; |
310 | } |
311 | EXPORT_SYMBOL_GPL(vfs_removexattr); |
312 | |
313 | |
314 | /* |
315 | * Extended attribute SET operations |
316 | */ |
317 | static long |
318 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
319 | size_t size, int flags) |
320 | { |
321 | int error; |
322 | void *kvalue = NULL; |
323 | char kname[XATTR_NAME_MAX + 1]; |
324 | |
325 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) |
326 | return -EINVAL; |
327 | |
328 | error = strncpy_from_user(kname, name, sizeof(kname)); |
329 | if (error == 0 || error == sizeof(kname)) |
330 | error = -ERANGE; |
331 | if (error < 0) |
332 | return error; |
333 | |
334 | if (size) { |
335 | if (size > XATTR_SIZE_MAX) |
336 | return -E2BIG; |
337 | kvalue = memdup_user(value, size); |
338 | if (IS_ERR(kvalue)) |
339 | return PTR_ERR(kvalue); |
340 | } |
341 | |
342 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
343 | kfree(kvalue); |
344 | return error; |
345 | } |
346 | |
347 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
348 | const char __user *, name, const void __user *, value, |
349 | size_t, size, int, flags) |
350 | { |
351 | struct path path; |
352 | int error; |
353 | |
354 | error = user_path(pathname, &path); |
355 | if (error) |
356 | return error; |
357 | error = mnt_want_write(path.mnt); |
358 | if (!error) { |
359 | error = setxattr(path.dentry, name, value, size, flags); |
360 | mnt_drop_write(path.mnt); |
361 | } |
362 | path_put(&path); |
363 | return error; |
364 | } |
365 | |
366 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
367 | const char __user *, name, const void __user *, value, |
368 | size_t, size, int, flags) |
369 | { |
370 | struct path path; |
371 | int error; |
372 | |
373 | error = user_lpath(pathname, &path); |
374 | if (error) |
375 | return error; |
376 | error = mnt_want_write(path.mnt); |
377 | if (!error) { |
378 | error = setxattr(path.dentry, name, value, size, flags); |
379 | mnt_drop_write(path.mnt); |
380 | } |
381 | path_put(&path); |
382 | return error; |
383 | } |
384 | |
385 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
386 | const void __user *,value, size_t, size, int, flags) |
387 | { |
388 | struct file *f; |
389 | struct dentry *dentry; |
390 | int error = -EBADF; |
391 | |
392 | f = fget(fd); |
393 | if (!f) |
394 | return error; |
395 | dentry = f->f_path.dentry; |
396 | audit_inode(NULL, dentry); |
397 | error = mnt_want_write_file(f); |
398 | if (!error) { |
399 | error = setxattr(dentry, name, value, size, flags); |
400 | mnt_drop_write_file(f); |
401 | } |
402 | fput(f); |
403 | return error; |
404 | } |
405 | |
406 | /* |
407 | * Extended attribute GET operations |
408 | */ |
409 | static ssize_t |
410 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
411 | size_t size) |
412 | { |
413 | ssize_t error; |
414 | void *kvalue = NULL; |
415 | char kname[XATTR_NAME_MAX + 1]; |
416 | |
417 | error = strncpy_from_user(kname, name, sizeof(kname)); |
418 | if (error == 0 || error == sizeof(kname)) |
419 | error = -ERANGE; |
420 | if (error < 0) |
421 | return error; |
422 | |
423 | if (size) { |
424 | if (size > XATTR_SIZE_MAX) |
425 | size = XATTR_SIZE_MAX; |
426 | kvalue = kzalloc(size, GFP_KERNEL); |
427 | if (!kvalue) |
428 | return -ENOMEM; |
429 | } |
430 | |
431 | error = vfs_getxattr(d, kname, kvalue, size); |
432 | if (error > 0) { |
433 | if (size && copy_to_user(value, kvalue, error)) |
434 | error = -EFAULT; |
435 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { |
436 | /* The file system tried to returned a value bigger |
437 | than XATTR_SIZE_MAX bytes. Not possible. */ |
438 | error = -E2BIG; |
439 | } |
440 | kfree(kvalue); |
441 | return error; |
442 | } |
443 | |
444 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
445 | const char __user *, name, void __user *, value, size_t, size) |
446 | { |
447 | struct path path; |
448 | ssize_t error; |
449 | |
450 | error = user_path(pathname, &path); |
451 | if (error) |
452 | return error; |
453 | error = getxattr(path.dentry, name, value, size); |
454 | path_put(&path); |
455 | return error; |
456 | } |
457 | |
458 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
459 | const char __user *, name, void __user *, value, size_t, size) |
460 | { |
461 | struct path path; |
462 | ssize_t error; |
463 | |
464 | error = user_lpath(pathname, &path); |
465 | if (error) |
466 | return error; |
467 | error = getxattr(path.dentry, name, value, size); |
468 | path_put(&path); |
469 | return error; |
470 | } |
471 | |
472 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
473 | void __user *, value, size_t, size) |
474 | { |
475 | struct file *f; |
476 | ssize_t error = -EBADF; |
477 | |
478 | f = fget(fd); |
479 | if (!f) |
480 | return error; |
481 | audit_inode(NULL, f->f_path.dentry); |
482 | error = getxattr(f->f_path.dentry, name, value, size); |
483 | fput(f); |
484 | return error; |
485 | } |
486 | |
487 | /* |
488 | * Extended attribute LIST operations |
489 | */ |
490 | static ssize_t |
491 | listxattr(struct dentry *d, char __user *list, size_t size) |
492 | { |
493 | ssize_t error; |
494 | char *klist = NULL; |
495 | |
496 | if (size) { |
497 | if (size > XATTR_LIST_MAX) |
498 | size = XATTR_LIST_MAX; |
499 | klist = kmalloc(size, GFP_KERNEL); |
500 | if (!klist) |
501 | return -ENOMEM; |
502 | } |
503 | |
504 | error = vfs_listxattr(d, klist, size); |
505 | if (error > 0) { |
506 | if (size && copy_to_user(list, klist, error)) |
507 | error = -EFAULT; |
508 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { |
509 | /* The file system tried to returned a list bigger |
510 | than XATTR_LIST_MAX bytes. Not possible. */ |
511 | error = -E2BIG; |
512 | } |
513 | kfree(klist); |
514 | return error; |
515 | } |
516 | |
517 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
518 | size_t, size) |
519 | { |
520 | struct path path; |
521 | ssize_t error; |
522 | |
523 | error = user_path(pathname, &path); |
524 | if (error) |
525 | return error; |
526 | error = listxattr(path.dentry, list, size); |
527 | path_put(&path); |
528 | return error; |
529 | } |
530 | |
531 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
532 | size_t, size) |
533 | { |
534 | struct path path; |
535 | ssize_t error; |
536 | |
537 | error = user_lpath(pathname, &path); |
538 | if (error) |
539 | return error; |
540 | error = listxattr(path.dentry, list, size); |
541 | path_put(&path); |
542 | return error; |
543 | } |
544 | |
545 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
546 | { |
547 | struct file *f; |
548 | ssize_t error = -EBADF; |
549 | |
550 | f = fget(fd); |
551 | if (!f) |
552 | return error; |
553 | audit_inode(NULL, f->f_path.dentry); |
554 | error = listxattr(f->f_path.dentry, list, size); |
555 | fput(f); |
556 | return error; |
557 | } |
558 | |
559 | /* |
560 | * Extended attribute REMOVE operations |
561 | */ |
562 | static long |
563 | removexattr(struct dentry *d, const char __user *name) |
564 | { |
565 | int error; |
566 | char kname[XATTR_NAME_MAX + 1]; |
567 | |
568 | error = strncpy_from_user(kname, name, sizeof(kname)); |
569 | if (error == 0 || error == sizeof(kname)) |
570 | error = -ERANGE; |
571 | if (error < 0) |
572 | return error; |
573 | |
574 | return vfs_removexattr(d, kname); |
575 | } |
576 | |
577 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
578 | const char __user *, name) |
579 | { |
580 | struct path path; |
581 | int error; |
582 | |
583 | error = user_path(pathname, &path); |
584 | if (error) |
585 | return error; |
586 | error = mnt_want_write(path.mnt); |
587 | if (!error) { |
588 | error = removexattr(path.dentry, name); |
589 | mnt_drop_write(path.mnt); |
590 | } |
591 | path_put(&path); |
592 | return error; |
593 | } |
594 | |
595 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
596 | const char __user *, name) |
597 | { |
598 | struct path path; |
599 | int error; |
600 | |
601 | error = user_lpath(pathname, &path); |
602 | if (error) |
603 | return error; |
604 | error = mnt_want_write(path.mnt); |
605 | if (!error) { |
606 | error = removexattr(path.dentry, name); |
607 | mnt_drop_write(path.mnt); |
608 | } |
609 | path_put(&path); |
610 | return error; |
611 | } |
612 | |
613 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
614 | { |
615 | struct file *f; |
616 | struct dentry *dentry; |
617 | int error = -EBADF; |
618 | |
619 | f = fget(fd); |
620 | if (!f) |
621 | return error; |
622 | dentry = f->f_path.dentry; |
623 | audit_inode(NULL, dentry); |
624 | error = mnt_want_write_file(f); |
625 | if (!error) { |
626 | error = removexattr(dentry, name); |
627 | mnt_drop_write_file(f); |
628 | } |
629 | fput(f); |
630 | return error; |
631 | } |
632 | |
633 | |
634 | static const char * |
635 | strcmp_prefix(const char *a, const char *a_prefix) |
636 | { |
637 | while (*a_prefix && *a == *a_prefix) { |
638 | a++; |
639 | a_prefix++; |
640 | } |
641 | return *a_prefix ? NULL : a; |
642 | } |
643 | |
644 | /* |
645 | * In order to implement different sets of xattr operations for each xattr |
646 | * prefix with the generic xattr API, a filesystem should create a |
647 | * null-terminated array of struct xattr_handler (one for each prefix) and |
648 | * hang a pointer to it off of the s_xattr field of the superblock. |
649 | * |
650 | * The generic_fooxattr() functions will use this list to dispatch xattr |
651 | * operations to the correct xattr_handler. |
652 | */ |
653 | #define for_each_xattr_handler(handlers, handler) \ |
654 | for ((handler) = *(handlers)++; \ |
655 | (handler) != NULL; \ |
656 | (handler) = *(handlers)++) |
657 | |
658 | /* |
659 | * Find the xattr_handler with the matching prefix. |
660 | */ |
661 | static const struct xattr_handler * |
662 | xattr_resolve_name(const struct xattr_handler **handlers, const char **name) |
663 | { |
664 | const struct xattr_handler *handler; |
665 | |
666 | if (!*name) |
667 | return NULL; |
668 | |
669 | for_each_xattr_handler(handlers, handler) { |
670 | const char *n = strcmp_prefix(*name, handler->prefix); |
671 | if (n) { |
672 | *name = n; |
673 | break; |
674 | } |
675 | } |
676 | return handler; |
677 | } |
678 | |
679 | /* |
680 | * Find the handler for the prefix and dispatch its get() operation. |
681 | */ |
682 | ssize_t |
683 | generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) |
684 | { |
685 | const struct xattr_handler *handler; |
686 | |
687 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
688 | if (!handler) |
689 | return -EOPNOTSUPP; |
690 | return handler->get(dentry, name, buffer, size, handler->flags); |
691 | } |
692 | |
693 | /* |
694 | * Combine the results of the list() operation from every xattr_handler in the |
695 | * list. |
696 | */ |
697 | ssize_t |
698 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) |
699 | { |
700 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
701 | unsigned int size = 0; |
702 | |
703 | if (!buffer) { |
704 | for_each_xattr_handler(handlers, handler) { |
705 | size += handler->list(dentry, NULL, 0, NULL, 0, |
706 | handler->flags); |
707 | } |
708 | } else { |
709 | char *buf = buffer; |
710 | |
711 | for_each_xattr_handler(handlers, handler) { |
712 | size = handler->list(dentry, buf, buffer_size, |
713 | NULL, 0, handler->flags); |
714 | if (size > buffer_size) |
715 | return -ERANGE; |
716 | buf += size; |
717 | buffer_size -= size; |
718 | } |
719 | size = buf - buffer; |
720 | } |
721 | return size; |
722 | } |
723 | |
724 | /* |
725 | * Find the handler for the prefix and dispatch its set() operation. |
726 | */ |
727 | int |
728 | generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) |
729 | { |
730 | const struct xattr_handler *handler; |
731 | |
732 | if (size == 0) |
733 | value = ""; /* empty EA, do not remove */ |
734 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
735 | if (!handler) |
736 | return -EOPNOTSUPP; |
737 | return handler->set(dentry, name, value, size, flags, handler->flags); |
738 | } |
739 | |
740 | /* |
741 | * Find the handler for the prefix and dispatch its set() operation to remove |
742 | * any associated extended attribute. |
743 | */ |
744 | int |
745 | generic_removexattr(struct dentry *dentry, const char *name) |
746 | { |
747 | const struct xattr_handler *handler; |
748 | |
749 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
750 | if (!handler) |
751 | return -EOPNOTSUPP; |
752 | return handler->set(dentry, name, NULL, 0, |
753 | XATTR_REPLACE, handler->flags); |
754 | } |
755 | |
756 | EXPORT_SYMBOL(generic_getxattr); |
757 | EXPORT_SYMBOL(generic_listxattr); |
758 | EXPORT_SYMBOL(generic_setxattr); |
759 | EXPORT_SYMBOL(generic_removexattr); |
760 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
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