Commit | Line | Data |
---|---|---|
1da177e4 LT |
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> | |
1da177e4 LT |
12 | #include <linux/file.h> |
13 | #include <linux/xattr.h> | |
18f335af | 14 | #include <linux/mount.h> |
1da177e4 LT |
15 | #include <linux/namei.h> |
16 | #include <linux/security.h> | |
17 | #include <linux/syscalls.h> | |
18 | #include <linux/module.h> | |
0eeca283 | 19 | #include <linux/fsnotify.h> |
73241ccc | 20 | #include <linux/audit.h> |
1da177e4 LT |
21 | #include <asm/uaccess.h> |
22 | ||
5be196e5 | 23 | |
e0ad7b07 | 24 | /* |
25 | * Check permissions for extended attribute access. This is a bit complicated | |
26 | * because different namespaces have very different rules. | |
27 | */ | |
28 | static int | |
29 | xattr_permission(struct inode *inode, const char *name, int mask) | |
30 | { | |
31 | /* | |
32 | * We can never set or remove an extended attribute on a read-only | |
33 | * filesystem or on an immutable / append-only inode. | |
34 | */ | |
35 | if (mask & MAY_WRITE) { | |
e0ad7b07 | 36 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
37 | return -EPERM; | |
38 | } | |
39 | ||
40 | /* | |
41 | * No restriction for security.* and system.* from the VFS. Decision | |
42 | * on these is left to the underlying filesystem / security module. | |
43 | */ | |
44 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || | |
45 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
46 | return 0; | |
47 | ||
48 | /* | |
f1f2d871 | 49 | * The trusted.* namespace can only be accessed by a privileged user. |
e0ad7b07 | 50 | */ |
51 | if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) | |
52 | return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM); | |
53 | ||
f1f2d871 AG |
54 | /* In user.* namespace, only regular files and directories can have |
55 | * extended attributes. For sticky directories, only the owner and | |
56 | * privileged user can write attributes. | |
57 | */ | |
e0ad7b07 | 58 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
f1f2d871 AG |
59 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
60 | return -EPERM; | |
61 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && | |
3bd858ab | 62 | (mask & MAY_WRITE) && !is_owner_or_cap(inode)) |
e0ad7b07 | 63 | return -EPERM; |
64 | } | |
65 | ||
66 | return permission(inode, mask, NULL); | |
67 | } | |
68 | ||
5be196e5 CH |
69 | int |
70 | vfs_setxattr(struct dentry *dentry, char *name, void *value, | |
71 | size_t size, int flags) | |
72 | { | |
73 | struct inode *inode = dentry->d_inode; | |
74 | int error; | |
75 | ||
e0ad7b07 | 76 | error = xattr_permission(inode, name, MAY_WRITE); |
77 | if (error) | |
78 | return error; | |
79 | ||
5be196e5 CH |
80 | mutex_lock(&inode->i_mutex); |
81 | error = security_inode_setxattr(dentry, name, value, size, flags); | |
82 | if (error) | |
83 | goto out; | |
84 | error = -EOPNOTSUPP; | |
85 | if (inode->i_op->setxattr) { | |
86 | error = inode->i_op->setxattr(dentry, name, value, size, flags); | |
87 | if (!error) { | |
88 | fsnotify_xattr(dentry); | |
89 | security_inode_post_setxattr(dentry, name, value, | |
90 | size, flags); | |
91 | } | |
92 | } else if (!strncmp(name, XATTR_SECURITY_PREFIX, | |
e0ad7b07 | 93 | XATTR_SECURITY_PREFIX_LEN)) { |
94 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
5be196e5 CH |
95 | error = security_inode_setsecurity(inode, suffix, value, |
96 | size, flags); | |
97 | if (!error) | |
98 | fsnotify_xattr(dentry); | |
99 | } | |
100 | out: | |
101 | mutex_unlock(&inode->i_mutex); | |
102 | return error; | |
103 | } | |
104 | EXPORT_SYMBOL_GPL(vfs_setxattr); | |
105 | ||
42492594 DQ |
106 | ssize_t |
107 | xattr_getsecurity(struct inode *inode, const char *name, void *value, | |
108 | size_t size) | |
109 | { | |
110 | void *buffer = NULL; | |
111 | ssize_t len; | |
112 | ||
113 | if (!value || !size) { | |
114 | len = security_inode_getsecurity(inode, name, &buffer, false); | |
115 | goto out_noalloc; | |
116 | } | |
117 | ||
118 | len = security_inode_getsecurity(inode, name, &buffer, true); | |
119 | if (len < 0) | |
120 | return len; | |
121 | if (size < len) { | |
122 | len = -ERANGE; | |
123 | goto out; | |
124 | } | |
125 | memcpy(value, buffer, len); | |
126 | out: | |
127 | security_release_secctx(buffer, len); | |
128 | out_noalloc: | |
129 | return len; | |
130 | } | |
131 | EXPORT_SYMBOL_GPL(xattr_getsecurity); | |
132 | ||
5be196e5 CH |
133 | ssize_t |
134 | vfs_getxattr(struct dentry *dentry, char *name, void *value, size_t size) | |
135 | { | |
136 | struct inode *inode = dentry->d_inode; | |
137 | int error; | |
138 | ||
e0ad7b07 | 139 | error = xattr_permission(inode, name, MAY_READ); |
140 | if (error) | |
141 | return error; | |
142 | ||
5be196e5 CH |
143 | error = security_inode_getxattr(dentry, name); |
144 | if (error) | |
145 | return error; | |
146 | ||
5be196e5 | 147 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b07 | 148 | XATTR_SECURITY_PREFIX_LEN)) { |
149 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
42492594 | 150 | int ret = xattr_getsecurity(inode, suffix, value, size); |
5be196e5 CH |
151 | /* |
152 | * Only overwrite the return value if a security module | |
153 | * is actually active. | |
154 | */ | |
4bea5805 DQ |
155 | if (ret == -EOPNOTSUPP) |
156 | goto nolsm; | |
157 | return ret; | |
5be196e5 | 158 | } |
4bea5805 DQ |
159 | nolsm: |
160 | if (inode->i_op->getxattr) | |
161 | error = inode->i_op->getxattr(dentry, name, value, size); | |
162 | else | |
163 | error = -EOPNOTSUPP; | |
5be196e5 CH |
164 | |
165 | return error; | |
166 | } | |
167 | EXPORT_SYMBOL_GPL(vfs_getxattr); | |
168 | ||
659564c8 BN |
169 | ssize_t |
170 | vfs_listxattr(struct dentry *d, char *list, size_t size) | |
171 | { | |
172 | ssize_t error; | |
173 | ||
174 | error = security_inode_listxattr(d); | |
175 | if (error) | |
176 | return error; | |
177 | error = -EOPNOTSUPP; | |
178 | if (d->d_inode->i_op && d->d_inode->i_op->listxattr) { | |
179 | error = d->d_inode->i_op->listxattr(d, list, size); | |
180 | } else { | |
181 | error = security_inode_listsecurity(d->d_inode, list, size); | |
182 | if (size && error > size) | |
183 | error = -ERANGE; | |
184 | } | |
185 | return error; | |
186 | } | |
187 | EXPORT_SYMBOL_GPL(vfs_listxattr); | |
188 | ||
5be196e5 CH |
189 | int |
190 | vfs_removexattr(struct dentry *dentry, char *name) | |
191 | { | |
192 | struct inode *inode = dentry->d_inode; | |
193 | int error; | |
194 | ||
195 | if (!inode->i_op->removexattr) | |
196 | return -EOPNOTSUPP; | |
197 | ||
e0ad7b07 | 198 | error = xattr_permission(inode, name, MAY_WRITE); |
199 | if (error) | |
200 | return error; | |
201 | ||
5be196e5 CH |
202 | error = security_inode_removexattr(dentry, name); |
203 | if (error) | |
204 | return error; | |
205 | ||
206 | mutex_lock(&inode->i_mutex); | |
207 | error = inode->i_op->removexattr(dentry, name); | |
208 | mutex_unlock(&inode->i_mutex); | |
209 | ||
210 | if (!error) | |
211 | fsnotify_xattr(dentry); | |
212 | return error; | |
213 | } | |
214 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
215 | ||
216 | ||
1da177e4 LT |
217 | /* |
218 | * Extended attribute SET operations | |
219 | */ | |
220 | static long | |
221 | setxattr(struct dentry *d, char __user *name, void __user *value, | |
222 | size_t size, int flags) | |
223 | { | |
224 | int error; | |
225 | void *kvalue = NULL; | |
226 | char kname[XATTR_NAME_MAX + 1]; | |
227 | ||
228 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) | |
229 | return -EINVAL; | |
230 | ||
231 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
232 | if (error == 0 || error == sizeof(kname)) | |
233 | error = -ERANGE; | |
234 | if (error < 0) | |
235 | return error; | |
236 | ||
237 | if (size) { | |
238 | if (size > XATTR_SIZE_MAX) | |
239 | return -E2BIG; | |
240 | kvalue = kmalloc(size, GFP_KERNEL); | |
241 | if (!kvalue) | |
242 | return -ENOMEM; | |
243 | if (copy_from_user(kvalue, value, size)) { | |
244 | kfree(kvalue); | |
245 | return -EFAULT; | |
246 | } | |
247 | } | |
248 | ||
5be196e5 | 249 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
f99d49ad | 250 | kfree(kvalue); |
1da177e4 LT |
251 | return error; |
252 | } | |
253 | ||
254 | asmlinkage long | |
255 | sys_setxattr(char __user *path, char __user *name, void __user *value, | |
256 | size_t size, int flags) | |
257 | { | |
258 | struct nameidata nd; | |
259 | int error; | |
260 | ||
261 | error = user_path_walk(path, &nd); | |
262 | if (error) | |
263 | return error; | |
18f335af DH |
264 | error = mnt_want_write(nd.path.mnt); |
265 | if (!error) { | |
266 | error = setxattr(nd.path.dentry, name, value, size, flags); | |
267 | mnt_drop_write(nd.path.mnt); | |
268 | } | |
1d957f9b | 269 | path_put(&nd.path); |
1da177e4 LT |
270 | return error; |
271 | } | |
272 | ||
273 | asmlinkage long | |
274 | sys_lsetxattr(char __user *path, char __user *name, void __user *value, | |
275 | size_t size, int flags) | |
276 | { | |
277 | struct nameidata nd; | |
278 | int error; | |
279 | ||
280 | error = user_path_walk_link(path, &nd); | |
281 | if (error) | |
282 | return error; | |
18f335af DH |
283 | error = mnt_want_write(nd.path.mnt); |
284 | if (!error) { | |
285 | error = setxattr(nd.path.dentry, name, value, size, flags); | |
286 | mnt_drop_write(nd.path.mnt); | |
287 | } | |
1d957f9b | 288 | path_put(&nd.path); |
1da177e4 LT |
289 | return error; |
290 | } | |
291 | ||
292 | asmlinkage long | |
293 | sys_fsetxattr(int fd, char __user *name, void __user *value, | |
294 | size_t size, int flags) | |
295 | { | |
296 | struct file *f; | |
73241ccc | 297 | struct dentry *dentry; |
1da177e4 LT |
298 | int error = -EBADF; |
299 | ||
300 | f = fget(fd); | |
301 | if (!f) | |
302 | return error; | |
0f7fc9e4 | 303 | dentry = f->f_path.dentry; |
5a190ae6 | 304 | audit_inode(NULL, dentry); |
18f335af DH |
305 | error = mnt_want_write(f->f_path.mnt); |
306 | if (!error) { | |
307 | error = setxattr(dentry, name, value, size, flags); | |
308 | mnt_drop_write(f->f_path.mnt); | |
309 | } | |
1da177e4 LT |
310 | fput(f); |
311 | return error; | |
312 | } | |
313 | ||
314 | /* | |
315 | * Extended attribute GET operations | |
316 | */ | |
317 | static ssize_t | |
318 | getxattr(struct dentry *d, char __user *name, void __user *value, size_t size) | |
319 | { | |
320 | ssize_t error; | |
321 | void *kvalue = NULL; | |
322 | char kname[XATTR_NAME_MAX + 1]; | |
323 | ||
324 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
325 | if (error == 0 || error == sizeof(kname)) | |
326 | error = -ERANGE; | |
327 | if (error < 0) | |
328 | return error; | |
329 | ||
330 | if (size) { | |
331 | if (size > XATTR_SIZE_MAX) | |
332 | size = XATTR_SIZE_MAX; | |
d381d8a9 | 333 | kvalue = kzalloc(size, GFP_KERNEL); |
1da177e4 LT |
334 | if (!kvalue) |
335 | return -ENOMEM; | |
336 | } | |
337 | ||
5be196e5 | 338 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 SS |
339 | if (error > 0) { |
340 | if (size && copy_to_user(value, kvalue, error)) | |
341 | error = -EFAULT; | |
342 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
343 | /* The file system tried to returned a value bigger | |
344 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
345 | error = -E2BIG; | |
1da177e4 | 346 | } |
f99d49ad | 347 | kfree(kvalue); |
1da177e4 LT |
348 | return error; |
349 | } | |
350 | ||
351 | asmlinkage ssize_t | |
352 | sys_getxattr(char __user *path, char __user *name, void __user *value, | |
353 | size_t size) | |
354 | { | |
355 | struct nameidata nd; | |
356 | ssize_t error; | |
357 | ||
358 | error = user_path_walk(path, &nd); | |
359 | if (error) | |
360 | return error; | |
4ac91378 | 361 | error = getxattr(nd.path.dentry, name, value, size); |
1d957f9b | 362 | path_put(&nd.path); |
1da177e4 LT |
363 | return error; |
364 | } | |
365 | ||
366 | asmlinkage ssize_t | |
367 | sys_lgetxattr(char __user *path, char __user *name, void __user *value, | |
368 | size_t size) | |
369 | { | |
370 | struct nameidata nd; | |
371 | ssize_t error; | |
372 | ||
373 | error = user_path_walk_link(path, &nd); | |
374 | if (error) | |
375 | return error; | |
4ac91378 | 376 | error = getxattr(nd.path.dentry, name, value, size); |
1d957f9b | 377 | path_put(&nd.path); |
1da177e4 LT |
378 | return error; |
379 | } | |
380 | ||
381 | asmlinkage ssize_t | |
382 | sys_fgetxattr(int fd, char __user *name, void __user *value, size_t size) | |
383 | { | |
384 | struct file *f; | |
385 | ssize_t error = -EBADF; | |
386 | ||
387 | f = fget(fd); | |
388 | if (!f) | |
389 | return error; | |
5a190ae6 | 390 | audit_inode(NULL, f->f_path.dentry); |
0f7fc9e4 | 391 | error = getxattr(f->f_path.dentry, name, value, size); |
1da177e4 LT |
392 | fput(f); |
393 | return error; | |
394 | } | |
395 | ||
396 | /* | |
397 | * Extended attribute LIST operations | |
398 | */ | |
399 | static ssize_t | |
400 | listxattr(struct dentry *d, char __user *list, size_t size) | |
401 | { | |
402 | ssize_t error; | |
403 | char *klist = NULL; | |
404 | ||
405 | if (size) { | |
406 | if (size > XATTR_LIST_MAX) | |
407 | size = XATTR_LIST_MAX; | |
408 | klist = kmalloc(size, GFP_KERNEL); | |
409 | if (!klist) | |
410 | return -ENOMEM; | |
411 | } | |
412 | ||
659564c8 | 413 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
414 | if (error > 0) { |
415 | if (size && copy_to_user(list, klist, error)) | |
416 | error = -EFAULT; | |
417 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
418 | /* The file system tried to returned a list bigger | |
419 | than XATTR_LIST_MAX bytes. Not possible. */ | |
420 | error = -E2BIG; | |
1da177e4 | 421 | } |
f99d49ad | 422 | kfree(klist); |
1da177e4 LT |
423 | return error; |
424 | } | |
425 | ||
426 | asmlinkage ssize_t | |
427 | sys_listxattr(char __user *path, char __user *list, size_t size) | |
428 | { | |
429 | struct nameidata nd; | |
430 | ssize_t error; | |
431 | ||
432 | error = user_path_walk(path, &nd); | |
433 | if (error) | |
434 | return error; | |
4ac91378 | 435 | error = listxattr(nd.path.dentry, list, size); |
1d957f9b | 436 | path_put(&nd.path); |
1da177e4 LT |
437 | return error; |
438 | } | |
439 | ||
440 | asmlinkage ssize_t | |
441 | sys_llistxattr(char __user *path, char __user *list, size_t size) | |
442 | { | |
443 | struct nameidata nd; | |
444 | ssize_t error; | |
445 | ||
446 | error = user_path_walk_link(path, &nd); | |
447 | if (error) | |
448 | return error; | |
4ac91378 | 449 | error = listxattr(nd.path.dentry, list, size); |
1d957f9b | 450 | path_put(&nd.path); |
1da177e4 LT |
451 | return error; |
452 | } | |
453 | ||
454 | asmlinkage ssize_t | |
455 | sys_flistxattr(int fd, char __user *list, size_t size) | |
456 | { | |
457 | struct file *f; | |
458 | ssize_t error = -EBADF; | |
459 | ||
460 | f = fget(fd); | |
461 | if (!f) | |
462 | return error; | |
5a190ae6 | 463 | audit_inode(NULL, f->f_path.dentry); |
0f7fc9e4 | 464 | error = listxattr(f->f_path.dentry, list, size); |
1da177e4 LT |
465 | fput(f); |
466 | return error; | |
467 | } | |
468 | ||
469 | /* | |
470 | * Extended attribute REMOVE operations | |
471 | */ | |
472 | static long | |
473 | removexattr(struct dentry *d, char __user *name) | |
474 | { | |
475 | int error; | |
476 | char kname[XATTR_NAME_MAX + 1]; | |
477 | ||
478 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
479 | if (error == 0 || error == sizeof(kname)) | |
480 | error = -ERANGE; | |
481 | if (error < 0) | |
482 | return error; | |
483 | ||
5be196e5 | 484 | return vfs_removexattr(d, kname); |
1da177e4 LT |
485 | } |
486 | ||
487 | asmlinkage long | |
488 | sys_removexattr(char __user *path, char __user *name) | |
489 | { | |
490 | struct nameidata nd; | |
491 | int error; | |
492 | ||
493 | error = user_path_walk(path, &nd); | |
494 | if (error) | |
495 | return error; | |
18f335af DH |
496 | error = mnt_want_write(nd.path.mnt); |
497 | if (!error) { | |
498 | error = removexattr(nd.path.dentry, name); | |
499 | mnt_drop_write(nd.path.mnt); | |
500 | } | |
1d957f9b | 501 | path_put(&nd.path); |
1da177e4 LT |
502 | return error; |
503 | } | |
504 | ||
505 | asmlinkage long | |
506 | sys_lremovexattr(char __user *path, char __user *name) | |
507 | { | |
508 | struct nameidata nd; | |
509 | int error; | |
510 | ||
511 | error = user_path_walk_link(path, &nd); | |
512 | if (error) | |
513 | return error; | |
18f335af DH |
514 | error = mnt_want_write(nd.path.mnt); |
515 | if (!error) { | |
516 | error = removexattr(nd.path.dentry, name); | |
517 | mnt_drop_write(nd.path.mnt); | |
518 | } | |
1d957f9b | 519 | path_put(&nd.path); |
1da177e4 LT |
520 | return error; |
521 | } | |
522 | ||
523 | asmlinkage long | |
524 | sys_fremovexattr(int fd, char __user *name) | |
525 | { | |
526 | struct file *f; | |
73241ccc | 527 | struct dentry *dentry; |
1da177e4 LT |
528 | int error = -EBADF; |
529 | ||
530 | f = fget(fd); | |
531 | if (!f) | |
532 | return error; | |
0f7fc9e4 | 533 | dentry = f->f_path.dentry; |
5a190ae6 | 534 | audit_inode(NULL, dentry); |
18f335af DH |
535 | error = mnt_want_write(f->f_path.mnt); |
536 | if (!error) { | |
537 | error = removexattr(dentry, name); | |
538 | mnt_drop_write(f->f_path.mnt); | |
539 | } | |
1da177e4 LT |
540 | fput(f); |
541 | return error; | |
542 | } | |
543 | ||
544 | ||
545 | static const char * | |
546 | strcmp_prefix(const char *a, const char *a_prefix) | |
547 | { | |
548 | while (*a_prefix && *a == *a_prefix) { | |
549 | a++; | |
550 | a_prefix++; | |
551 | } | |
552 | return *a_prefix ? NULL : a; | |
553 | } | |
554 | ||
555 | /* | |
556 | * In order to implement different sets of xattr operations for each xattr | |
557 | * prefix with the generic xattr API, a filesystem should create a | |
558 | * null-terminated array of struct xattr_handler (one for each prefix) and | |
559 | * hang a pointer to it off of the s_xattr field of the superblock. | |
560 | * | |
561 | * The generic_fooxattr() functions will use this list to dispatch xattr | |
562 | * operations to the correct xattr_handler. | |
563 | */ | |
564 | #define for_each_xattr_handler(handlers, handler) \ | |
565 | for ((handler) = *(handlers)++; \ | |
566 | (handler) != NULL; \ | |
567 | (handler) = *(handlers)++) | |
568 | ||
569 | /* | |
570 | * Find the xattr_handler with the matching prefix. | |
571 | */ | |
572 | static struct xattr_handler * | |
573 | xattr_resolve_name(struct xattr_handler **handlers, const char **name) | |
574 | { | |
575 | struct xattr_handler *handler; | |
576 | ||
577 | if (!*name) | |
578 | return NULL; | |
579 | ||
580 | for_each_xattr_handler(handlers, handler) { | |
581 | const char *n = strcmp_prefix(*name, handler->prefix); | |
582 | if (n) { | |
583 | *name = n; | |
584 | break; | |
585 | } | |
586 | } | |
587 | return handler; | |
588 | } | |
589 | ||
590 | /* | |
591 | * Find the handler for the prefix and dispatch its get() operation. | |
592 | */ | |
593 | ssize_t | |
594 | generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) | |
595 | { | |
596 | struct xattr_handler *handler; | |
597 | struct inode *inode = dentry->d_inode; | |
598 | ||
599 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); | |
600 | if (!handler) | |
601 | return -EOPNOTSUPP; | |
602 | return handler->get(inode, name, buffer, size); | |
603 | } | |
604 | ||
605 | /* | |
606 | * Combine the results of the list() operation from every xattr_handler in the | |
607 | * list. | |
608 | */ | |
609 | ssize_t | |
610 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
611 | { | |
612 | struct inode *inode = dentry->d_inode; | |
613 | struct xattr_handler *handler, **handlers = inode->i_sb->s_xattr; | |
614 | unsigned int size = 0; | |
615 | ||
616 | if (!buffer) { | |
617 | for_each_xattr_handler(handlers, handler) | |
618 | size += handler->list(inode, NULL, 0, NULL, 0); | |
619 | } else { | |
620 | char *buf = buffer; | |
621 | ||
622 | for_each_xattr_handler(handlers, handler) { | |
623 | size = handler->list(inode, buf, buffer_size, NULL, 0); | |
624 | if (size > buffer_size) | |
625 | return -ERANGE; | |
626 | buf += size; | |
627 | buffer_size -= size; | |
628 | } | |
629 | size = buf - buffer; | |
630 | } | |
631 | return size; | |
632 | } | |
633 | ||
634 | /* | |
635 | * Find the handler for the prefix and dispatch its set() operation. | |
636 | */ | |
637 | int | |
638 | generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) | |
639 | { | |
640 | struct xattr_handler *handler; | |
641 | struct inode *inode = dentry->d_inode; | |
642 | ||
643 | if (size == 0) | |
644 | value = ""; /* empty EA, do not remove */ | |
645 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); | |
646 | if (!handler) | |
647 | return -EOPNOTSUPP; | |
648 | return handler->set(inode, name, value, size, flags); | |
649 | } | |
650 | ||
651 | /* | |
652 | * Find the handler for the prefix and dispatch its set() operation to remove | |
653 | * any associated extended attribute. | |
654 | */ | |
655 | int | |
656 | generic_removexattr(struct dentry *dentry, const char *name) | |
657 | { | |
658 | struct xattr_handler *handler; | |
659 | struct inode *inode = dentry->d_inode; | |
660 | ||
661 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); | |
662 | if (!handler) | |
663 | return -EOPNOTSUPP; | |
664 | return handler->set(inode, name, NULL, 0, XATTR_REPLACE); | |
665 | } | |
666 | ||
667 | EXPORT_SYMBOL(generic_getxattr); | |
668 | EXPORT_SYMBOL(generic_listxattr); | |
669 | EXPORT_SYMBOL(generic_setxattr); | |
670 | EXPORT_SYMBOL(generic_removexattr); |