2 Unix SMB/CIFS implementation.
4 Generic, persistent and shared between processes cache mechanism for use
5 by various parts of the Samba code
7 Copyright (C) Rafal Szczesniak 2002
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>.
24 #include "system/time.h"
25 #include "system/filesys.h"
27 #include "lib/gencache/gencache.h"
29 #define TIMEOUT_LEN 12
30 #define CACHE_DATA_FMT "%12u/%s"
32 static struct tdb_wrap *cache;
36 * @brief Generic, persistent and shared between processes cache mechanism
37 * for use by various parts of the Samba code
43 * Cache initialisation function. Opens cache tdb file or creates
44 * it if does not exist.
46 * @return true on successful initialisation of the cache or
50 BOOL gencache_init(void)
52 char* cache_fname = NULL;
54 /* skip file open if it's already opened */
55 if (cache) return True;
57 asprintf(&cache_fname, "%s/%s", lp_lockdir(), "gencache.tdb");
59 DEBUG(5, ("Opening cache file at %s\n", cache_fname));
61 DEBUG(0, ("Filename allocation failed.\n"));
65 cache = tdb_wrap_open(NULL, cache_fname, 0, TDB_DEFAULT,
66 O_RDWR|O_CREAT, 0644);
68 SAFE_FREE(cache_fname);
70 DEBUG(5, ("Attempt to open gencache.tdb has failed.\n"));
78 * Cache shutdown function. Closes opened cache tdb file.
80 * @return true on successful closing the cache or
81 * false on failure during cache shutdown
84 BOOL gencache_shutdown(void)
86 if (!cache) return False;
87 DEBUG(5, ("Closing cache file\n"));
94 * Set an entry in the cache file. If there's no such
97 * @param keystr string that represents a key of this entry
98 * @param value text representation value being cached
99 * @param timeout time when the value is expired
101 * @retval true when entry is successfuly stored
102 * @retval false on failure
105 BOOL gencache_set(const char *keystr, const char *value, time_t timeout)
108 TDB_DATA keybuf, databuf;
111 /* fail completely if get null pointers passed */
112 SMB_ASSERT(keystr && value);
114 if (!gencache_init()) return False;
116 asprintf(&valstr, CACHE_DATA_FMT, (int)timeout, value);
120 keybuf.dptr = (uint8_t *)strdup(keystr);
121 keybuf.dsize = strlen(keystr)+1;
122 databuf.dptr = (uint8_t *)strdup(valstr);
123 databuf.dsize = strlen(valstr)+1;
124 DEBUG(10, ("Adding cache entry with key = %s; value = %s and timeout \
125 = %s (%d seconds %s)\n", keybuf.dptr, value, ctime(&timeout),
126 (int)(timeout - time(NULL)), timeout > time(NULL) ? "ahead" : "in the past"));
128 ret = tdb_store(cache->tdb, keybuf, databuf, 0);
130 SAFE_FREE(keybuf.dptr);
131 SAFE_FREE(databuf.dptr);
138 * Set existing entry to the cache file.
140 * @param keystr string that represents a key of this entry
141 * @param valstr text representation value being cached
142 * @param timeout time when the value is expired
144 * @retval true when entry is successfuly set
145 * @retval false on failure
148 BOOL gencache_set_only(const char *keystr, const char *valstr, time_t timeout)
151 TDB_DATA keybuf, databuf;
152 char *old_valstr, *datastr;
155 /* fail completely if get null pointers passed */
156 SMB_ASSERT(keystr && valstr);
158 if (!gencache_init()) return False;
161 * Check whether entry exists in the cache
162 * Don't verify gencache_get exit code, since the entry may be expired
164 gencache_get(keystr, &old_valstr, &old_timeout);
166 if (!(old_valstr && old_timeout)) return False;
168 DEBUG(10, ("Setting cache entry with key = %s; old value = %s and old timeout \
169 = %s\n", keystr, old_valstr, ctime(&old_timeout)));
171 asprintf(&datastr, CACHE_DATA_FMT, (int)timeout, valstr);
172 keybuf.dptr = (uint8_t *)strdup(keystr);
173 keybuf.dsize = strlen(keystr)+1;
174 databuf.dptr = (uint8_t *)strdup(datastr);
175 databuf.dsize = strlen(datastr)+1;
176 DEBUGADD(10, ("New value = %s, new timeout = %s (%d seconds %s)", valstr,
177 ctime(&timeout), (int)(timeout - time(NULL)),
178 timeout > time(NULL) ? "ahead" : "in the past"));
181 ret = tdb_store(cache->tdb, keybuf, databuf, TDB_REPLACE);
184 SAFE_FREE(old_valstr);
185 SAFE_FREE(keybuf.dptr);
186 SAFE_FREE(databuf.dptr);
193 * Delete one entry from the cache file.
195 * @param keystr string that represents a key of this entry
197 * @retval true upon successful deletion
198 * @retval false in case of failure
201 BOOL gencache_del(const char *keystr)
206 /* fail completely if get null pointers passed */
209 if (!gencache_init()) return False;
211 keybuf.dptr = (uint8_t *)strdup(keystr);
212 keybuf.dsize = strlen(keystr)+1;
213 DEBUG(10, ("Deleting cache entry (key = %s)\n", keystr));
214 ret = tdb_delete(cache->tdb, keybuf);
216 SAFE_FREE(keybuf.dptr);
222 * Get existing entry from the cache file.
224 * @param keystr string that represents a key of this entry
225 * @param valstr buffer that is allocated and filled with the entry value
226 * buffer's disposing must be done outside
227 * @param timeout pointer to a time_t that is filled with entry's
230 * @retval true when entry is successfuly fetched
231 * @retval False for failure
234 BOOL gencache_get(const char *keystr, char **valstr, time_t *timeout)
236 TDB_DATA keybuf, databuf;
238 /* fail completely if get null pointers passed */
241 if (!gencache_init())
244 keybuf.dptr = (uint8_t *)strdup(keystr);
245 keybuf.dsize = strlen(keystr)+1;
246 databuf = tdb_fetch(cache->tdb, keybuf);
247 SAFE_FREE(keybuf.dptr);
249 if (databuf.dptr && databuf.dsize > TIMEOUT_LEN) {
250 char* entry_buf = strndup((char *)databuf.dptr, databuf.dsize);
255 v = malloc_array_p(char, databuf.dsize - TIMEOUT_LEN);
257 SAFE_FREE(databuf.dptr);
258 sscanf(entry_buf, CACHE_DATA_FMT, (int*)&i, v);
259 SAFE_FREE(entry_buf);
262 DEBUG(10, ("Returning %s cache entry: key = %s, value = %s, "
263 "timeout = %s\n", t > time(NULL) ? "valid" :
264 "expired", keystr, v, ctime(&t)));
274 return t > time(NULL);
277 SAFE_FREE(databuf.dptr);
285 DEBUG(10, ("Cache entry with key = %s couldn't be found\n",
294 * Iterate through all entries which key matches to specified pattern
296 * @param fn pointer to the function that will be supplied with each single
297 * matching cache entry (key, value and timeout) as an arguments
298 * @param data void pointer to an arbitrary data that is passed directly to the fn
299 * function on each call
300 * @param keystr_pattern pattern the existing entries' keys are matched to
304 void gencache_iterate(void (*fn)(const char* key, const char *value, time_t timeout, void* dptr),
305 void* data, const char* keystr_pattern)
307 TDB_LIST_NODE *node, *first_node;
309 char *keystr = NULL, *valstr = NULL, *entry = NULL;
313 /* fail completely if get null pointers passed */
314 SMB_ASSERT(fn && keystr_pattern);
316 if (!gencache_init()) return;
318 DEBUG(5, ("Searching cache keys with pattern %s\n", keystr_pattern));
319 node = tdb_search_keys(cache->tdb, keystr_pattern);
323 /* ensure null termination of the key string */
324 keystr = strndup((char *)node->node_key.dptr, node->node_key.dsize);
327 * We don't use gencache_get function, because we need to iterate through
328 * all of the entries. Validity verification is up to fn routine.
330 databuf = tdb_fetch(cache->tdb, node->node_key);
331 if (!databuf.dptr || databuf.dsize <= TIMEOUT_LEN) {
332 SAFE_FREE(databuf.dptr);
337 entry = strndup((char *)databuf.dptr, databuf.dsize);
338 SAFE_FREE(databuf.dptr);
339 valstr = malloc_array_p(char, databuf.dsize - TIMEOUT_LEN);
340 sscanf(entry, CACHE_DATA_FMT, (int*)(&i), valstr);
343 DEBUG(10, ("Calling function with arguments (key = %s, value = %s, timeout = %s)\n",
344 keystr, valstr, ctime(&timeout)));
345 fn(keystr, valstr, timeout, data);
353 tdb_search_list_free(first_node);
356 /********************************************************************
358 ********************************************************************/
360 int gencache_lock_entry( const char *key )
362 return tdb_lock_bystring(cache->tdb, key);
365 /********************************************************************
367 ********************************************************************/
369 void gencache_unlock_entry( const char *key )
371 tdb_unlock_bystring(cache->tdb, key);