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5b88fdd9 SF |
1 | /* |
2 | * Copyright (C) 2014-2016 Junjiro R. Okajima | |
3 | * | |
4 | * This program, aufs is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
16 | */ | |
17 | ||
18 | /* | |
19 | * handling xattr functions | |
20 | */ | |
21 | ||
22 | #include <linux/xattr.h> | |
23 | #include "aufs.h" | |
24 | ||
25 | static int au_xattr_ignore(int err, char *name, unsigned int ignore_flags) | |
26 | { | |
27 | if (!ignore_flags) | |
28 | goto out; | |
29 | switch (err) { | |
30 | case -ENOMEM: | |
31 | case -EDQUOT: | |
32 | goto out; | |
33 | } | |
34 | ||
35 | if ((ignore_flags & AuBrAttr_ICEX) == AuBrAttr_ICEX) { | |
36 | err = 0; | |
37 | goto out; | |
38 | } | |
39 | ||
40 | #define cmp(brattr, prefix) do { \ | |
41 | if (!strncmp(name, XATTR_##prefix##_PREFIX, \ | |
42 | XATTR_##prefix##_PREFIX_LEN)) { \ | |
43 | if (ignore_flags & AuBrAttr_ICEX_##brattr) \ | |
44 | err = 0; \ | |
45 | goto out; \ | |
46 | } \ | |
47 | } while (0) | |
48 | ||
49 | cmp(SEC, SECURITY); | |
50 | cmp(SYS, SYSTEM); | |
51 | cmp(TR, TRUSTED); | |
52 | cmp(USR, USER); | |
53 | #undef cmp | |
54 | ||
55 | if (ignore_flags & AuBrAttr_ICEX_OTH) | |
56 | err = 0; | |
57 | ||
58 | out: | |
59 | return err; | |
60 | } | |
61 | ||
62 | static const int au_xattr_out_of_list = AuBrAttr_ICEX_OTH << 1; | |
63 | ||
64 | static int au_do_cpup_xattr(struct dentry *h_dst, struct dentry *h_src, | |
65 | char *name, char **buf, unsigned int ignore_flags, | |
66 | unsigned int verbose) | |
67 | { | |
68 | int err; | |
69 | ssize_t ssz; | |
70 | struct inode *h_idst; | |
71 | ||
72 | ssz = vfs_getxattr_alloc(h_src, name, buf, 0, GFP_NOFS); | |
73 | err = ssz; | |
74 | if (unlikely(err <= 0)) { | |
75 | if (err == -ENODATA | |
76 | || (err == -EOPNOTSUPP | |
77 | && ((ignore_flags & au_xattr_out_of_list) | |
78 | || (au_test_nfs_noacl(d_inode(h_src)) | |
79 | && (!strcmp(name, XATTR_NAME_POSIX_ACL_ACCESS) | |
80 | || !strcmp(name, | |
81 | XATTR_NAME_POSIX_ACL_DEFAULT)))) | |
82 | )) | |
83 | err = 0; | |
84 | if (err && (verbose || au_debug_test())) | |
85 | pr_err("%s, err %d\n", name, err); | |
86 | goto out; | |
87 | } | |
88 | ||
89 | /* unlock it temporary */ | |
90 | h_idst = d_inode(h_dst); | |
91 | inode_unlock(h_idst); | |
92 | err = vfsub_setxattr(h_dst, name, *buf, ssz, /*flags*/0); | |
93 | inode_lock_nested(h_idst, AuLsc_I_CHILD2); | |
94 | if (unlikely(err)) { | |
95 | if (verbose || au_debug_test()) | |
96 | pr_err("%s, err %d\n", name, err); | |
97 | err = au_xattr_ignore(err, name, ignore_flags); | |
98 | } | |
99 | ||
100 | out: | |
101 | return err; | |
102 | } | |
103 | ||
104 | int au_cpup_xattr(struct dentry *h_dst, struct dentry *h_src, int ignore_flags, | |
105 | unsigned int verbose) | |
106 | { | |
107 | int err, unlocked, acl_access, acl_default; | |
108 | ssize_t ssz; | |
109 | struct inode *h_isrc, *h_idst; | |
110 | char *value, *p, *o, *e; | |
111 | ||
112 | /* try stopping to update the source inode while we are referencing */ | |
113 | /* there should not be the parent-child relationship between them */ | |
114 | h_isrc = d_inode(h_src); | |
115 | h_idst = d_inode(h_dst); | |
116 | inode_unlock(h_idst); | |
117 | inode_lock_nested(h_isrc, AuLsc_I_CHILD); | |
118 | inode_lock_nested(h_idst, AuLsc_I_CHILD2); | |
119 | unlocked = 0; | |
120 | ||
121 | /* some filesystems don't list POSIX ACL, for example tmpfs */ | |
122 | ssz = vfs_listxattr(h_src, NULL, 0); | |
123 | err = ssz; | |
124 | if (unlikely(err < 0)) { | |
125 | AuTraceErr(err); | |
126 | if (err == -ENODATA | |
127 | || err == -EOPNOTSUPP) | |
128 | err = 0; /* ignore */ | |
129 | goto out; | |
130 | } | |
131 | ||
132 | err = 0; | |
133 | p = NULL; | |
134 | o = NULL; | |
135 | if (ssz) { | |
136 | err = -ENOMEM; | |
137 | p = kmalloc(ssz, GFP_NOFS); | |
138 | o = p; | |
139 | if (unlikely(!p)) | |
140 | goto out; | |
141 | err = vfs_listxattr(h_src, p, ssz); | |
142 | } | |
143 | inode_unlock(h_isrc); | |
144 | unlocked = 1; | |
145 | AuDbg("err %d, ssz %zd\n", err, ssz); | |
146 | if (unlikely(err < 0)) | |
147 | goto out_free; | |
148 | ||
149 | err = 0; | |
150 | e = p + ssz; | |
151 | value = NULL; | |
152 | acl_access = 0; | |
153 | acl_default = 0; | |
154 | while (!err && p < e) { | |
155 | acl_access |= !strncmp(p, XATTR_NAME_POSIX_ACL_ACCESS, | |
156 | sizeof(XATTR_NAME_POSIX_ACL_ACCESS) - 1); | |
157 | acl_default |= !strncmp(p, XATTR_NAME_POSIX_ACL_DEFAULT, | |
158 | sizeof(XATTR_NAME_POSIX_ACL_DEFAULT) | |
159 | - 1); | |
160 | err = au_do_cpup_xattr(h_dst, h_src, p, &value, ignore_flags, | |
161 | verbose); | |
162 | p += strlen(p) + 1; | |
163 | } | |
164 | AuTraceErr(err); | |
165 | ignore_flags |= au_xattr_out_of_list; | |
166 | if (!err && !acl_access) { | |
167 | err = au_do_cpup_xattr(h_dst, h_src, | |
168 | XATTR_NAME_POSIX_ACL_ACCESS, &value, | |
169 | ignore_flags, verbose); | |
170 | AuTraceErr(err); | |
171 | } | |
172 | if (!err && !acl_default) { | |
173 | err = au_do_cpup_xattr(h_dst, h_src, | |
174 | XATTR_NAME_POSIX_ACL_DEFAULT, &value, | |
175 | ignore_flags, verbose); | |
176 | AuTraceErr(err); | |
177 | } | |
178 | ||
179 | if (value) | |
180 | au_delayed_kfree(value); | |
181 | ||
182 | out_free: | |
183 | if (o) | |
184 | au_delayed_kfree(o); | |
185 | out: | |
186 | if (!unlocked) | |
187 | inode_unlock(h_isrc); | |
188 | AuTraceErr(err); | |
189 | return err; | |
190 | } | |
191 | ||
192 | /* ---------------------------------------------------------------------- */ | |
193 | ||
194 | enum { | |
195 | AU_XATTR_LIST, | |
196 | AU_XATTR_GET | |
197 | }; | |
198 | ||
199 | struct au_lgxattr { | |
200 | int type; | |
201 | union { | |
202 | struct { | |
203 | char *list; | |
204 | size_t size; | |
205 | } list; | |
206 | struct { | |
207 | const char *name; | |
208 | void *value; | |
209 | size_t size; | |
210 | } get; | |
211 | } u; | |
212 | }; | |
213 | ||
214 | static ssize_t au_lgxattr(struct dentry *dentry, struct au_lgxattr *arg) | |
215 | { | |
216 | ssize_t err; | |
217 | struct path h_path; | |
218 | struct super_block *sb; | |
219 | ||
220 | sb = dentry->d_sb; | |
221 | err = si_read_lock(sb, AuLock_FLUSH | AuLock_NOPLM); | |
222 | if (unlikely(err)) | |
223 | goto out; | |
224 | err = au_h_path_getattr(dentry, /*force*/1, &h_path); | |
225 | if (unlikely(err)) | |
226 | goto out_si; | |
227 | if (unlikely(!h_path.dentry)) | |
228 | /* illegally overlapped or something */ | |
229 | goto out_di; /* pretending success */ | |
230 | ||
231 | /* always topmost entry only */ | |
232 | switch (arg->type) { | |
233 | case AU_XATTR_LIST: | |
234 | err = vfs_listxattr(h_path.dentry, | |
235 | arg->u.list.list, arg->u.list.size); | |
236 | break; | |
237 | case AU_XATTR_GET: | |
238 | AuDebugOn(d_is_negative(h_path.dentry)); | |
239 | err = vfs_getxattr(h_path.dentry, | |
240 | arg->u.get.name, arg->u.get.value, | |
241 | arg->u.get.size); | |
242 | break; | |
243 | } | |
244 | ||
245 | out_di: | |
246 | di_read_unlock(dentry, AuLock_IR); | |
247 | out_si: | |
248 | si_read_unlock(sb); | |
249 | out: | |
250 | AuTraceErr(err); | |
251 | return err; | |
252 | } | |
253 | ||
254 | ssize_t aufs_listxattr(struct dentry *dentry, char *list, size_t size) | |
255 | { | |
256 | struct au_lgxattr arg = { | |
257 | .type = AU_XATTR_LIST, | |
258 | .u.list = { | |
259 | .list = list, | |
260 | .size = size | |
261 | }, | |
262 | }; | |
263 | ||
264 | return au_lgxattr(dentry, &arg); | |
265 | } | |
266 | ||
b7ca57c6 SF |
267 | ssize_t aufs_getxattr(struct dentry *dentry, struct inode *inode __maybe_unused, |
268 | const char *name, void *value, size_t size) | |
5b88fdd9 SF |
269 | { |
270 | struct au_lgxattr arg = { | |
271 | .type = AU_XATTR_GET, | |
272 | .u.get = { | |
273 | .name = name, | |
274 | .value = value, | |
275 | .size = size | |
276 | }, | |
277 | }; | |
278 | ||
279 | return au_lgxattr(dentry, &arg); | |
280 | } | |
281 | ||
b7ca57c6 SF |
282 | int aufs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, |
283 | const void *value, size_t size, int flags) | |
5b88fdd9 SF |
284 | { |
285 | struct au_srxattr arg = { | |
286 | .type = AU_XATTR_SET, | |
287 | .u.set = { | |
288 | .name = name, | |
289 | .value = value, | |
290 | .size = size, | |
291 | .flags = flags | |
292 | }, | |
293 | }; | |
294 | ||
295 | return au_srxattr(dentry, inode, &arg); | |
296 | } | |
297 | ||
b7ca57c6 | 298 | int aufs_removexattr(struct dentry *dentry, const char *name) |
5b88fdd9 SF |
299 | { |
300 | struct au_srxattr arg = { | |
301 | .type = AU_XATTR_REMOVE, | |
302 | .u.remove = { | |
303 | .name = name | |
304 | }, | |
305 | }; | |
306 | ||
307 | return au_srxattr(dentry, d_inode(dentry), &arg); | |
308 | } | |
309 | ||
b7ca57c6 SF |
310 | /* ---------------------------------------------------------------------- */ |
311 | ||
312 | #if 0 | |
313 | static size_t au_xattr_list(struct dentry *dentry, char *list, size_t list_size, | |
314 | const char *name, size_t name_len, int type) | |
5b88fdd9 | 315 | { |
b7ca57c6 | 316 | return aufs_listxattr(dentry, list, list_size); |
5b88fdd9 SF |
317 | } |
318 | ||
b7ca57c6 SF |
319 | static int au_xattr_get(struct dentry *dentry, const char *name, void *buffer, |
320 | size_t size, int type) | |
5b88fdd9 | 321 | { |
b7ca57c6 SF |
322 | return aufs_getxattr(dentry, name, buffer, size); |
323 | } | |
324 | ||
325 | static int au_xattr_set(struct dentry *dentry, const char *name, | |
326 | const void *value, size_t size, int flags, int type) | |
327 | { | |
328 | return aufs_setxattr(dentry, name, value, size, flags); | |
5b88fdd9 SF |
329 | } |
330 | ||
331 | static const struct xattr_handler au_xattr_handler = { | |
b7ca57c6 SF |
332 | /* no prefix, no flags */ |
333 | .list = au_xattr_list, | |
334 | .get = au_xattr_get, | |
335 | .set = au_xattr_set | |
336 | /* why no remove? */ | |
5b88fdd9 SF |
337 | }; |
338 | ||
339 | static const struct xattr_handler *au_xattr_handlers[] = { | |
b7ca57c6 | 340 | &au_xattr_handler |
5b88fdd9 SF |
341 | }; |
342 | ||
343 | void au_xattr_init(struct super_block *sb) | |
344 | { | |
b7ca57c6 | 345 | /* sb->s_xattr = au_xattr_handlers; */ |
5b88fdd9 | 346 | } |
b7ca57c6 | 347 | #endif |