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e0e72660 JG |
1 | /* |
2 | * Copyright (C) 2018 - Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License, version 2 only, as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program; if not, write to the Free Software Foundation, Inc., 51 | |
15 | * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
16 | */ | |
17 | ||
18 | #include <sys/types.h> | |
19 | #include <sys/stat.h> | |
20 | #include <unistd.h> | |
21 | #include <inttypes.h> | |
22 | #include <urcu.h> | |
23 | #include <urcu/ref.h> | |
24 | #include <urcu/rculfhash.h> | |
25 | #include <common/hashtable/utils.h> | |
26 | #include <common/macros.h> | |
27 | #include <common/defaults.h> | |
28 | #include <common/error.h> | |
29 | #include <lttng/constant.h> | |
30 | ||
31 | #include "inode.h" | |
32 | ||
33 | struct inode_id { | |
34 | dev_t device; | |
35 | ino_t inode; | |
36 | }; | |
37 | ||
38 | struct lttng_inode_registry { | |
39 | /* Hashtable of inode_id to lttng_inode. */ | |
40 | struct cds_lfht *inodes; | |
41 | }; | |
42 | ||
43 | struct lttng_inode { | |
44 | struct inode_id id; | |
45 | char *path; | |
46 | bool unlink_pending; | |
47 | /* Node in the lttng_inode_registry's ht. */ | |
48 | struct cds_lfht_node registry_node; | |
49 | /* Weak reference to ht containing the node. */ | |
50 | struct cds_lfht *registry_ht; | |
51 | struct urcu_ref ref; | |
52 | struct rcu_head rcu_head; | |
53 | }; | |
54 | ||
55 | static struct { | |
56 | pthread_mutex_t lock; | |
57 | bool initialized; | |
58 | unsigned long value; | |
59 | } seed = { | |
60 | .lock = PTHREAD_MUTEX_INITIALIZER, | |
61 | }; | |
62 | ||
63 | static | |
64 | unsigned long lttng_inode_id_hash(struct inode_id *id) | |
65 | { | |
66 | uint64_t device = id->device, inode_no = id->inode; | |
67 | ||
68 | return hash_key_u64(&device, seed.value) ^ | |
69 | hash_key_u64(&inode_no, seed.value); | |
70 | } | |
71 | ||
72 | static | |
73 | int lttng_inode_match(struct cds_lfht_node *node, const void *key) | |
74 | { | |
75 | const struct inode_id *id = key; | |
76 | struct lttng_inode *inode = caa_container_of(node, struct lttng_inode, | |
77 | registry_node); | |
78 | ||
79 | return inode->id.device == id->device && inode->id.inode == id->inode; | |
80 | } | |
81 | ||
82 | static | |
83 | void lttng_inode_delete(struct rcu_head *head) | |
84 | { | |
85 | struct lttng_inode *inode = caa_container_of(head, | |
86 | struct lttng_inode, rcu_head); | |
87 | ||
88 | free(inode->path); | |
89 | free(inode); | |
90 | } | |
91 | ||
92 | static | |
93 | void lttng_inode_destroy(struct lttng_inode *inode) | |
94 | { | |
95 | if (!inode) { | |
96 | return; | |
97 | } | |
98 | if (inode->unlink_pending) { | |
99 | int ret = unlink(inode->path); | |
100 | ||
101 | DBG("Unlinking %s during lttng_inode destruction", inode->path); | |
102 | if (ret) { | |
103 | PERROR("Failed to unlink %s", inode->path); | |
104 | } | |
105 | } | |
106 | rcu_read_lock(); | |
107 | cds_lfht_del(inode->registry_ht, &inode->registry_node); | |
108 | rcu_read_unlock(); | |
109 | call_rcu(&inode->rcu_head, lttng_inode_delete); | |
110 | } | |
111 | ||
112 | static | |
113 | void lttng_inode_release(struct urcu_ref *ref) | |
114 | { | |
115 | lttng_inode_destroy(caa_container_of(ref, struct lttng_inode, ref)); | |
116 | } | |
117 | ||
118 | static | |
119 | void lttng_inode_get(struct lttng_inode *inode) | |
120 | { | |
121 | urcu_ref_get(&inode->ref); | |
122 | } | |
123 | ||
124 | void lttng_inode_put(struct lttng_inode *inode) | |
125 | { | |
126 | urcu_ref_put(&inode->ref, lttng_inode_release); | |
127 | } | |
128 | ||
129 | const char *lttng_inode_get_path(const struct lttng_inode *inode) | |
130 | { | |
131 | return inode->path; | |
132 | } | |
133 | ||
134 | int lttng_inode_rename(struct lttng_inode *inode, const char *new_path, | |
135 | bool overwrite) | |
136 | { | |
137 | int ret = 0; | |
138 | char *new_path_copy = NULL; | |
139 | ||
140 | if (inode->unlink_pending) { | |
141 | WARN("An attempt to rename an unlinked file, %s to %s, has been performed", | |
142 | inode->path, new_path); | |
143 | ret = -ENOENT; | |
144 | goto end; | |
145 | } | |
146 | ||
147 | if (!overwrite) { | |
148 | struct stat statbuf; | |
149 | ||
150 | ret = stat(new_path, &statbuf); | |
151 | if (ret == 0) { | |
152 | ret = -EEXIST; | |
153 | goto end; | |
154 | } else if (ret < 0 && errno != ENOENT) { | |
155 | PERROR("Failed to stat() %s", new_path); | |
156 | ret = -errno; | |
157 | goto end; | |
158 | } | |
159 | } | |
160 | ||
161 | new_path_copy = strdup(new_path); | |
162 | if (!new_path_copy) { | |
163 | ERR("Failed to allocate storage for path %s", new_path); | |
164 | ret = -ENOMEM; | |
165 | goto end; | |
166 | } | |
167 | ||
168 | ret = rename(inode->path, new_path); | |
169 | if (ret) { | |
170 | PERROR("Failed to rename %s to %s", inode->path, new_path); | |
171 | ret = -errno; | |
172 | goto end; | |
173 | } | |
174 | ||
175 | free(inode->path); | |
176 | inode->path = new_path_copy; | |
177 | new_path_copy = NULL; | |
178 | end: | |
179 | free(new_path_copy); | |
180 | return ret; | |
181 | } | |
182 | ||
183 | int lttng_inode_defer_unlink(struct lttng_inode *inode) | |
184 | { | |
185 | int ret = 0; | |
186 | uint16_t i = 0; | |
187 | char suffix[sizeof("-deleted-65535")] = "-deleted"; | |
188 | char new_path[LTTNG_PATH_MAX]; | |
189 | size_t original_path_len = strlen(inode->path); | |
190 | ||
191 | if (inode->unlink_pending) { | |
192 | WARN("An attempt to re-unlink %s has been performed, ignoring.", | |
193 | inode->path); | |
194 | ret = -ENOENT; | |
195 | goto end; | |
196 | } | |
197 | ||
198 | ret = lttng_strncpy(new_path, inode->path, sizeof(new_path)); | |
199 | if (ret < 0) { | |
200 | ret = -ENAMETOOLONG; | |
201 | goto end; | |
202 | } | |
203 | ||
204 | for (i = 0; i < UINT16_MAX; i++) { | |
205 | int p_ret; | |
206 | ||
207 | if (i != 0) { | |
208 | p_ret = snprintf(suffix, sizeof(suffix), "-deleted-%" PRIu16, i); | |
209 | ||
210 | if (p_ret < 0) { | |
211 | PERROR("Failed to form suffix to rename file %s", | |
212 | inode->path); | |
213 | ret = -errno; | |
214 | goto end; | |
215 | } | |
216 | assert(p_ret != sizeof(suffix)); | |
217 | } else { | |
218 | /* suffix is initialy set to '-deleted'. */ | |
219 | p_ret = strlen(suffix); | |
220 | } | |
221 | ||
222 | if (original_path_len + p_ret + 1 >= sizeof(new_path)) { | |
223 | ret = -ENAMETOOLONG; | |
224 | goto end; | |
225 | } | |
226 | ||
227 | strcat(&new_path[original_path_len], suffix); | |
228 | ret = lttng_inode_rename(inode, new_path, false); | |
229 | if (ret != -EEXIST) { | |
230 | break; | |
231 | } | |
232 | new_path[original_path_len] = '\0'; | |
233 | } | |
234 | if (!ret) { | |
235 | inode->unlink_pending = true; | |
236 | } | |
237 | end: | |
238 | return ret; | |
239 | } | |
240 | ||
241 | static | |
242 | struct lttng_inode *lttng_inode_create(const struct inode_id *id, | |
243 | const char *path, struct cds_lfht *ht) | |
244 | { | |
245 | struct lttng_inode *inode = zmalloc(sizeof(*inode)); | |
246 | ||
247 | if (!inode) { | |
248 | goto end; | |
249 | } | |
250 | ||
251 | urcu_ref_init(&inode->ref); | |
252 | cds_lfht_node_init(&inode->registry_node); | |
253 | inode->id = *id; | |
254 | inode->path = strdup(path); | |
255 | inode->registry_ht = ht; | |
256 | if (!inode->path) { | |
257 | goto error; | |
258 | } | |
259 | end: | |
260 | return inode; | |
261 | error: | |
262 | lttng_inode_destroy(inode); | |
263 | return NULL; | |
264 | } | |
265 | ||
266 | struct lttng_inode_registry *lttng_inode_registry_create(void) | |
267 | { | |
268 | struct lttng_inode_registry *registry = zmalloc(sizeof(*registry)); | |
269 | ||
270 | if (!registry) { | |
271 | goto end; | |
272 | } | |
273 | ||
274 | pthread_mutex_lock(&seed.lock); | |
275 | if (!seed.initialized) { | |
276 | seed.value = (unsigned long) time(NULL); | |
277 | seed.initialized = true; | |
278 | } | |
279 | pthread_mutex_unlock(&seed.lock); | |
280 | ||
281 | registry->inodes = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0, | |
282 | CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL); | |
283 | if (!registry->inodes) { | |
284 | goto error; | |
285 | } | |
286 | end: | |
287 | return registry; | |
288 | error: | |
289 | lttng_inode_registry_destroy(registry); | |
290 | return NULL; | |
291 | } | |
292 | ||
293 | void lttng_inode_registry_destroy(struct lttng_inode_registry *registry) | |
294 | { | |
295 | if (!registry) { | |
296 | return; | |
297 | } | |
298 | if (registry->inodes) { | |
299 | int ret = cds_lfht_destroy(registry->inodes, NULL); | |
300 | ||
301 | assert(!ret); | |
302 | } | |
303 | free(registry); | |
304 | } | |
305 | ||
306 | struct lttng_inode *lttng_inode_registry_get_inode( | |
307 | struct lttng_inode_registry *registry, | |
308 | int fd, const char *path) | |
309 | { | |
310 | int ret; | |
311 | struct stat statbuf; | |
312 | struct inode_id id; | |
313 | struct cds_lfht_iter iter; | |
314 | struct cds_lfht_node *node; | |
315 | struct lttng_inode *inode = NULL; | |
316 | ||
317 | ret = fstat(fd, &statbuf); | |
318 | if (ret < 0) { | |
319 | PERROR("stat() failed on file %s, fd = %i", path, fd); | |
320 | goto end; | |
321 | } | |
322 | ||
323 | id.device = statbuf.st_dev; | |
324 | id.inode = statbuf.st_ino; | |
325 | ||
326 | rcu_read_lock(); | |
327 | cds_lfht_lookup(registry->inodes, | |
328 | lttng_inode_id_hash(&id), | |
329 | lttng_inode_match, | |
330 | &id, | |
331 | &iter); | |
332 | node = cds_lfht_iter_get_node(&iter); | |
333 | if (node) { | |
334 | inode = caa_container_of(node, struct lttng_inode, registry_node); | |
335 | /* Renames should happen through the fs-handle interface. */ | |
336 | assert(!strcmp(path, inode->path)); | |
337 | lttng_inode_get(inode); | |
338 | goto end_unlock; | |
339 | } | |
340 | ||
341 | inode = lttng_inode_create(&id, path, registry->inodes); | |
342 | node = cds_lfht_add_unique(registry->inodes, | |
343 | lttng_inode_id_hash(&inode->id), | |
344 | lttng_inode_match, | |
345 | &inode->id, | |
346 | &inode->registry_node); | |
347 | assert(node == &inode->registry_node); | |
348 | end_unlock: | |
349 | rcu_read_unlock(); | |
350 | end: | |
351 | return inode; | |
352 | } |