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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 | ||
f419a2e3 | 66 | return inode_permission(inode, mask); |
e0ad7b07 | 67 | } |
68 | ||
5be196e5 | 69 | int |
8f0cfa52 | 70 | vfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
5be196e5 CH |
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 | 133 | ssize_t |
8f0cfa52 | 134 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
5be196e5 CH |
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; | |
acfa4380 | 178 | if (d->d_inode->i_op->listxattr) { |
659564c8 BN |
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 | 189 | int |
8f0cfa52 | 190 | vfs_removexattr(struct dentry *dentry, const char *name) |
5be196e5 CH |
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 | |
8f0cfa52 | 221 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4 LT |
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 | |
2d8f3038 | 255 | sys_setxattr(const char __user *pathname, const char __user *name, |
8f0cfa52 | 256 | const void __user *value, size_t size, int flags) |
1da177e4 | 257 | { |
2d8f3038 | 258 | struct path path; |
1da177e4 LT |
259 | int error; |
260 | ||
2d8f3038 | 261 | error = user_path(pathname, &path); |
1da177e4 LT |
262 | if (error) |
263 | return error; | |
2d8f3038 | 264 | error = mnt_want_write(path.mnt); |
18f335af | 265 | if (!error) { |
2d8f3038 AV |
266 | error = setxattr(path.dentry, name, value, size, flags); |
267 | mnt_drop_write(path.mnt); | |
18f335af | 268 | } |
2d8f3038 | 269 | path_put(&path); |
1da177e4 LT |
270 | return error; |
271 | } | |
272 | ||
273 | asmlinkage long | |
2d8f3038 | 274 | sys_lsetxattr(const char __user *pathname, const char __user *name, |
8f0cfa52 | 275 | const void __user *value, size_t size, int flags) |
1da177e4 | 276 | { |
2d8f3038 | 277 | struct path path; |
1da177e4 LT |
278 | int error; |
279 | ||
2d8f3038 | 280 | error = user_lpath(pathname, &path); |
1da177e4 LT |
281 | if (error) |
282 | return error; | |
2d8f3038 | 283 | error = mnt_want_write(path.mnt); |
18f335af | 284 | if (!error) { |
2d8f3038 AV |
285 | error = setxattr(path.dentry, name, value, size, flags); |
286 | mnt_drop_write(path.mnt); | |
18f335af | 287 | } |
2d8f3038 | 288 | path_put(&path); |
1da177e4 LT |
289 | return error; |
290 | } | |
291 | ||
292 | asmlinkage long | |
8f0cfa52 | 293 | sys_fsetxattr(int fd, const char __user *name, const void __user *value, |
1da177e4 LT |
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 | |
8f0cfa52 DH |
318 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
319 | size_t size) | |
1da177e4 LT |
320 | { |
321 | ssize_t error; | |
322 | void *kvalue = NULL; | |
323 | char kname[XATTR_NAME_MAX + 1]; | |
324 | ||
325 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
326 | if (error == 0 || error == sizeof(kname)) | |
327 | error = -ERANGE; | |
328 | if (error < 0) | |
329 | return error; | |
330 | ||
331 | if (size) { | |
332 | if (size > XATTR_SIZE_MAX) | |
333 | size = XATTR_SIZE_MAX; | |
d381d8a9 | 334 | kvalue = kzalloc(size, GFP_KERNEL); |
1da177e4 LT |
335 | if (!kvalue) |
336 | return -ENOMEM; | |
337 | } | |
338 | ||
5be196e5 | 339 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 SS |
340 | if (error > 0) { |
341 | if (size && copy_to_user(value, kvalue, error)) | |
342 | error = -EFAULT; | |
343 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
344 | /* The file system tried to returned a value bigger | |
345 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
346 | error = -E2BIG; | |
1da177e4 | 347 | } |
f99d49ad | 348 | kfree(kvalue); |
1da177e4 LT |
349 | return error; |
350 | } | |
351 | ||
2ed7c03e | 352 | asmlinkage long |
2d8f3038 | 353 | sys_getxattr(const char __user *pathname, const char __user *name, |
8f0cfa52 | 354 | void __user *value, size_t size) |
1da177e4 | 355 | { |
2d8f3038 | 356 | struct path path; |
1da177e4 LT |
357 | ssize_t error; |
358 | ||
2d8f3038 | 359 | error = user_path(pathname, &path); |
1da177e4 LT |
360 | if (error) |
361 | return error; | |
2d8f3038 AV |
362 | error = getxattr(path.dentry, name, value, size); |
363 | path_put(&path); | |
1da177e4 LT |
364 | return error; |
365 | } | |
366 | ||
2ed7c03e | 367 | asmlinkage long |
2d8f3038 | 368 | sys_lgetxattr(const char __user *pathname, const char __user *name, void __user *value, |
1da177e4 LT |
369 | size_t size) |
370 | { | |
2d8f3038 | 371 | struct path path; |
1da177e4 LT |
372 | ssize_t error; |
373 | ||
2d8f3038 | 374 | error = user_lpath(pathname, &path); |
1da177e4 LT |
375 | if (error) |
376 | return error; | |
2d8f3038 AV |
377 | error = getxattr(path.dentry, name, value, size); |
378 | path_put(&path); | |
1da177e4 LT |
379 | return error; |
380 | } | |
381 | ||
2ed7c03e | 382 | asmlinkage long |
8f0cfa52 | 383 | sys_fgetxattr(int fd, const char __user *name, void __user *value, size_t size) |
1da177e4 LT |
384 | { |
385 | struct file *f; | |
386 | ssize_t error = -EBADF; | |
387 | ||
388 | f = fget(fd); | |
389 | if (!f) | |
390 | return error; | |
5a190ae6 | 391 | audit_inode(NULL, f->f_path.dentry); |
0f7fc9e4 | 392 | error = getxattr(f->f_path.dentry, name, value, size); |
1da177e4 LT |
393 | fput(f); |
394 | return error; | |
395 | } | |
396 | ||
397 | /* | |
398 | * Extended attribute LIST operations | |
399 | */ | |
400 | static ssize_t | |
401 | listxattr(struct dentry *d, char __user *list, size_t size) | |
402 | { | |
403 | ssize_t error; | |
404 | char *klist = NULL; | |
405 | ||
406 | if (size) { | |
407 | if (size > XATTR_LIST_MAX) | |
408 | size = XATTR_LIST_MAX; | |
409 | klist = kmalloc(size, GFP_KERNEL); | |
410 | if (!klist) | |
411 | return -ENOMEM; | |
412 | } | |
413 | ||
659564c8 | 414 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
415 | if (error > 0) { |
416 | if (size && copy_to_user(list, klist, error)) | |
417 | error = -EFAULT; | |
418 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
419 | /* The file system tried to returned a list bigger | |
420 | than XATTR_LIST_MAX bytes. Not possible. */ | |
421 | error = -E2BIG; | |
1da177e4 | 422 | } |
f99d49ad | 423 | kfree(klist); |
1da177e4 LT |
424 | return error; |
425 | } | |
426 | ||
2ed7c03e | 427 | asmlinkage long |
2d8f3038 | 428 | sys_listxattr(const char __user *pathname, char __user *list, size_t size) |
1da177e4 | 429 | { |
2d8f3038 | 430 | struct path path; |
1da177e4 LT |
431 | ssize_t error; |
432 | ||
2d8f3038 | 433 | error = user_path(pathname, &path); |
1da177e4 LT |
434 | if (error) |
435 | return error; | |
2d8f3038 AV |
436 | error = listxattr(path.dentry, list, size); |
437 | path_put(&path); | |
1da177e4 LT |
438 | return error; |
439 | } | |
440 | ||
2ed7c03e | 441 | asmlinkage long |
2d8f3038 | 442 | sys_llistxattr(const char __user *pathname, char __user *list, size_t size) |
1da177e4 | 443 | { |
2d8f3038 | 444 | struct path path; |
1da177e4 LT |
445 | ssize_t error; |
446 | ||
2d8f3038 | 447 | error = user_lpath(pathname, &path); |
1da177e4 LT |
448 | if (error) |
449 | return error; | |
2d8f3038 AV |
450 | error = listxattr(path.dentry, list, size); |
451 | path_put(&path); | |
1da177e4 LT |
452 | return error; |
453 | } | |
454 | ||
2ed7c03e | 455 | asmlinkage long |
1da177e4 LT |
456 | sys_flistxattr(int fd, char __user *list, size_t size) |
457 | { | |
458 | struct file *f; | |
459 | ssize_t error = -EBADF; | |
460 | ||
461 | f = fget(fd); | |
462 | if (!f) | |
463 | return error; | |
5a190ae6 | 464 | audit_inode(NULL, f->f_path.dentry); |
0f7fc9e4 | 465 | error = listxattr(f->f_path.dentry, list, size); |
1da177e4 LT |
466 | fput(f); |
467 | return error; | |
468 | } | |
469 | ||
470 | /* | |
471 | * Extended attribute REMOVE operations | |
472 | */ | |
473 | static long | |
8f0cfa52 | 474 | removexattr(struct dentry *d, const char __user *name) |
1da177e4 LT |
475 | { |
476 | int error; | |
477 | char kname[XATTR_NAME_MAX + 1]; | |
478 | ||
479 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
480 | if (error == 0 || error == sizeof(kname)) | |
481 | error = -ERANGE; | |
482 | if (error < 0) | |
483 | return error; | |
484 | ||
5be196e5 | 485 | return vfs_removexattr(d, kname); |
1da177e4 LT |
486 | } |
487 | ||
488 | asmlinkage long | |
2d8f3038 | 489 | sys_removexattr(const char __user *pathname, const char __user *name) |
1da177e4 | 490 | { |
2d8f3038 | 491 | struct path path; |
1da177e4 LT |
492 | int error; |
493 | ||
2d8f3038 | 494 | error = user_path(pathname, &path); |
1da177e4 LT |
495 | if (error) |
496 | return error; | |
2d8f3038 | 497 | error = mnt_want_write(path.mnt); |
18f335af | 498 | if (!error) { |
2d8f3038 AV |
499 | error = removexattr(path.dentry, name); |
500 | mnt_drop_write(path.mnt); | |
18f335af | 501 | } |
2d8f3038 | 502 | path_put(&path); |
1da177e4 LT |
503 | return error; |
504 | } | |
505 | ||
506 | asmlinkage long | |
2d8f3038 | 507 | sys_lremovexattr(const char __user *pathname, const char __user *name) |
1da177e4 | 508 | { |
2d8f3038 | 509 | struct path path; |
1da177e4 LT |
510 | int error; |
511 | ||
2d8f3038 | 512 | error = user_lpath(pathname, &path); |
1da177e4 LT |
513 | if (error) |
514 | return error; | |
2d8f3038 | 515 | error = mnt_want_write(path.mnt); |
18f335af | 516 | if (!error) { |
2d8f3038 AV |
517 | error = removexattr(path.dentry, name); |
518 | mnt_drop_write(path.mnt); | |
18f335af | 519 | } |
2d8f3038 | 520 | path_put(&path); |
1da177e4 LT |
521 | return error; |
522 | } | |
523 | ||
524 | asmlinkage long | |
8f0cfa52 | 525 | sys_fremovexattr(int fd, const char __user *name) |
1da177e4 LT |
526 | { |
527 | struct file *f; | |
73241ccc | 528 | struct dentry *dentry; |
1da177e4 LT |
529 | int error = -EBADF; |
530 | ||
531 | f = fget(fd); | |
532 | if (!f) | |
533 | return error; | |
0f7fc9e4 | 534 | dentry = f->f_path.dentry; |
5a190ae6 | 535 | audit_inode(NULL, dentry); |
18f335af DH |
536 | error = mnt_want_write(f->f_path.mnt); |
537 | if (!error) { | |
538 | error = removexattr(dentry, name); | |
539 | mnt_drop_write(f->f_path.mnt); | |
540 | } | |
1da177e4 LT |
541 | fput(f); |
542 | return error; | |
543 | } | |
544 | ||
545 | ||
546 | static const char * | |
547 | strcmp_prefix(const char *a, const char *a_prefix) | |
548 | { | |
549 | while (*a_prefix && *a == *a_prefix) { | |
550 | a++; | |
551 | a_prefix++; | |
552 | } | |
553 | return *a_prefix ? NULL : a; | |
554 | } | |
555 | ||
556 | /* | |
557 | * In order to implement different sets of xattr operations for each xattr | |
558 | * prefix with the generic xattr API, a filesystem should create a | |
559 | * null-terminated array of struct xattr_handler (one for each prefix) and | |
560 | * hang a pointer to it off of the s_xattr field of the superblock. | |
561 | * | |
562 | * The generic_fooxattr() functions will use this list to dispatch xattr | |
563 | * operations to the correct xattr_handler. | |
564 | */ | |
565 | #define for_each_xattr_handler(handlers, handler) \ | |
566 | for ((handler) = *(handlers)++; \ | |
567 | (handler) != NULL; \ | |
568 | (handler) = *(handlers)++) | |
569 | ||
570 | /* | |
571 | * Find the xattr_handler with the matching prefix. | |
572 | */ | |
573 | static struct xattr_handler * | |
574 | xattr_resolve_name(struct xattr_handler **handlers, const char **name) | |
575 | { | |
576 | struct xattr_handler *handler; | |
577 | ||
578 | if (!*name) | |
579 | return NULL; | |
580 | ||
581 | for_each_xattr_handler(handlers, handler) { | |
582 | const char *n = strcmp_prefix(*name, handler->prefix); | |
583 | if (n) { | |
584 | *name = n; | |
585 | break; | |
586 | } | |
587 | } | |
588 | return handler; | |
589 | } | |
590 | ||
591 | /* | |
592 | * Find the handler for the prefix and dispatch its get() operation. | |
593 | */ | |
594 | ssize_t | |
595 | generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) | |
596 | { | |
597 | struct xattr_handler *handler; | |
598 | struct inode *inode = dentry->d_inode; | |
599 | ||
600 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); | |
601 | if (!handler) | |
602 | return -EOPNOTSUPP; | |
603 | return handler->get(inode, name, buffer, size); | |
604 | } | |
605 | ||
606 | /* | |
607 | * Combine the results of the list() operation from every xattr_handler in the | |
608 | * list. | |
609 | */ | |
610 | ssize_t | |
611 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
612 | { | |
613 | struct inode *inode = dentry->d_inode; | |
614 | struct xattr_handler *handler, **handlers = inode->i_sb->s_xattr; | |
615 | unsigned int size = 0; | |
616 | ||
617 | if (!buffer) { | |
618 | for_each_xattr_handler(handlers, handler) | |
619 | size += handler->list(inode, NULL, 0, NULL, 0); | |
620 | } else { | |
621 | char *buf = buffer; | |
622 | ||
623 | for_each_xattr_handler(handlers, handler) { | |
624 | size = handler->list(inode, buf, buffer_size, NULL, 0); | |
625 | if (size > buffer_size) | |
626 | return -ERANGE; | |
627 | buf += size; | |
628 | buffer_size -= size; | |
629 | } | |
630 | size = buf - buffer; | |
631 | } | |
632 | return size; | |
633 | } | |
634 | ||
635 | /* | |
636 | * Find the handler for the prefix and dispatch its set() operation. | |
637 | */ | |
638 | int | |
639 | generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) | |
640 | { | |
641 | struct xattr_handler *handler; | |
642 | struct inode *inode = dentry->d_inode; | |
643 | ||
644 | if (size == 0) | |
645 | value = ""; /* empty EA, do not remove */ | |
646 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); | |
647 | if (!handler) | |
648 | return -EOPNOTSUPP; | |
649 | return handler->set(inode, name, value, size, flags); | |
650 | } | |
651 | ||
652 | /* | |
653 | * Find the handler for the prefix and dispatch its set() operation to remove | |
654 | * any associated extended attribute. | |
655 | */ | |
656 | int | |
657 | generic_removexattr(struct dentry *dentry, const char *name) | |
658 | { | |
659 | struct xattr_handler *handler; | |
660 | struct inode *inode = dentry->d_inode; | |
661 | ||
662 | handler = xattr_resolve_name(inode->i_sb->s_xattr, &name); | |
663 | if (!handler) | |
664 | return -EOPNOTSUPP; | |
665 | return handler->set(inode, name, NULL, 0, XATTR_REPLACE); | |
666 | } | |
667 | ||
668 | EXPORT_SYMBOL(generic_getxattr); | |
669 | EXPORT_SYMBOL(generic_listxattr); | |
670 | EXPORT_SYMBOL(generic_setxattr); | |
671 | EXPORT_SYMBOL(generic_removexattr); |