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 2 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, write to the Free Software
21 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
27 #define DBGC_CLASS DBGC_TDB
29 #define TIMEOUT_LEN 12
30 #define CACHE_DATA_FMT "%12u/%s"
31 #define READ_CACHE_DATA_FMT_TEMPLATE "%%12u/%%%us"
33 static TDB_CONTEXT *cache;
37 * @brief Generic, persistent and shared between processes cache mechanism
38 * for use by various parts of the Samba code
44 * Cache initialisation function. Opens cache tdb file or creates
45 * it if does not exist.
47 * @return true on successful initialisation of the cache or
51 BOOL gencache_init(void)
53 char* cache_fname = NULL;
55 /* skip file open if it's already opened */
56 if (cache) return True;
58 asprintf(&cache_fname, "%s/%s", lp_lockdir(), "gencache.tdb");
60 DEBUG(5, ("Opening cache file at %s\n", cache_fname));
62 DEBUG(0, ("Filename allocation failed.\n"));
66 cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT,
67 O_RDWR|O_CREAT, 0644);
69 SAFE_FREE(cache_fname);
71 DEBUG(5, ("Attempt to open gencache.tdb has failed.\n"));
79 * Cache shutdown function. Closes opened cache tdb file.
81 * @return true on successful closing the cache or
82 * false on failure during cache shutdown
85 BOOL gencache_shutdown(void)
88 /* tdb_close routine returns -1 on error */
89 if (!cache) return False;
90 DEBUG(5, ("Closing cache file\n"));
91 ret = tdb_close(cache);
98 * Set an entry in the cache file. If there's no such
101 * @param keystr string that represents a key of this entry
102 * @param value text representation value being cached
103 * @param timeout time when the value is expired
105 * @retval true when entry is successfuly stored
106 * @retval false on failure
109 BOOL gencache_set(const char *keystr, const char *value, time_t timeout)
112 TDB_DATA keybuf, databuf;
115 /* fail completely if get null pointers passed */
116 SMB_ASSERT(keystr && value);
118 if (!gencache_init()) return False;
120 asprintf(&valstr, CACHE_DATA_FMT, (int)timeout, value);
124 keybuf.dptr = SMB_STRDUP(keystr);
125 keybuf.dsize = strlen(keystr)+1;
126 databuf.dptr = SMB_STRDUP(valstr);
127 databuf.dsize = strlen(valstr)+1;
128 DEBUG(10, ("Adding cache entry with key = %s; value = %s and timeout ="
129 " %s (%d seconds %s)\n", keybuf.dptr, value,ctime(&timeout),
130 (int)(timeout - time(NULL)),
131 timeout > time(NULL) ? "ahead" : "in the past"));
133 ret = tdb_store(cache, keybuf, databuf, 0);
135 SAFE_FREE(keybuf.dptr);
136 SAFE_FREE(databuf.dptr);
143 * Set existing entry to the cache file.
145 * @param keystr string that represents a key of this entry
146 * @param valstr text representation value being cached
147 * @param timeout time when the value is expired
149 * @retval true when entry is successfuly set
150 * @retval false on failure
153 BOOL gencache_set_only(const char *keystr, const char *valstr, time_t timeout)
156 TDB_DATA keybuf, databuf;
157 char *old_valstr, *datastr;
160 /* fail completely if get null pointers passed */
161 SMB_ASSERT(keystr && valstr);
163 if (!gencache_init()) return False;
166 * Check whether entry exists in the cache
167 * Don't verify gencache_get exit code, since the entry may be expired
169 gencache_get(keystr, &old_valstr, &old_timeout);
171 if (!(old_valstr && old_timeout)) return False;
173 DEBUG(10, ("Setting cache entry with key = %s; old value = %s and old timeout \
174 = %s\n", keystr, old_valstr, ctime(&old_timeout)));
176 asprintf(&datastr, CACHE_DATA_FMT, (int)timeout, valstr);
177 keybuf.dptr = SMB_STRDUP(keystr);
178 keybuf.dsize = strlen(keystr)+1;
179 databuf.dptr = SMB_STRDUP(datastr);
180 databuf.dsize = strlen(datastr)+1;
181 DEBUGADD(10, ("New value = %s, new timeout = %s (%d seconds %s)", valstr,
182 ctime(&timeout), (int)(timeout - time(NULL)),
183 timeout > time(NULL) ? "ahead" : "in the past"));
186 ret = tdb_store(cache, keybuf, databuf, TDB_REPLACE);
189 SAFE_FREE(old_valstr);
190 SAFE_FREE(keybuf.dptr);
191 SAFE_FREE(databuf.dptr);
198 * Delete one entry from the cache file.
200 * @param keystr string that represents a key of this entry
202 * @retval true upon successful deletion
203 * @retval false in case of failure
206 BOOL gencache_del(const char *keystr)
211 /* fail completely if get null pointers passed */
214 if (!gencache_init()) return False;
216 keybuf.dptr = SMB_STRDUP(keystr);
217 keybuf.dsize = strlen(keystr)+1;
218 DEBUG(10, ("Deleting cache entry (key = %s)\n", keystr));
219 ret = tdb_delete(cache, keybuf);
221 SAFE_FREE(keybuf.dptr);
227 * Get existing entry from the cache file.
229 * @param keystr string that represents a key of this entry
230 * @param valstr buffer that is allocated and filled with the entry value
231 * buffer's disposing must be done outside
232 * @param timeout pointer to a time_t that is filled with entry's
235 * @retval true when entry is successfuly fetched
236 * @retval False for failure
239 BOOL gencache_get(const char *keystr, char **valstr, time_t *timeout)
241 TDB_DATA keybuf, databuf;
243 /* fail completely if get null pointers passed */
246 if (!gencache_init()) {
250 keybuf.dptr = SMB_STRDUP(keystr);
251 keybuf.dsize = strlen(keystr)+1;
252 databuf = tdb_fetch(cache, keybuf);
253 SAFE_FREE(keybuf.dptr);
255 if (databuf.dptr && databuf.dsize > TIMEOUT_LEN) {
256 char* entry_buf = SMB_STRNDUP(databuf.dptr, databuf.dsize);
263 v = SMB_MALLOC(databuf.dsize + 1 - TIMEOUT_LEN);
268 SAFE_FREE(databuf.dptr);
270 asprintf(&fmt, READ_CACHE_DATA_FMT_TEMPLATE, (unsigned int)databuf.dsize - TIMEOUT_LEN);
276 status = sscanf(entry_buf, fmt, &u, v);
280 DEBUG(0, ("gencache_get: Invalid return %d from sscanf\n", status ));
283 SAFE_FREE(entry_buf);
285 DEBUG(10, ("Returning %s cache entry: key = %s, value = %s, "
286 "timeout = %s", t > time(NULL) ? "valid" :
287 "expired", keystr, v, ctime(&t)));
299 return t > time(NULL);
303 SAFE_FREE(databuf.dptr);
312 DEBUG(10, ("Cache entry with key = %s couldn't be found\n", keystr));
317 * Iterate through all entries which key matches to specified pattern
319 * @param fn pointer to the function that will be supplied with each single
320 * matching cache entry (key, value and timeout) as an arguments
321 * @param data void pointer to an arbitrary data that is passed directly to the fn
322 * function on each call
323 * @param keystr_pattern pattern the existing entries' keys are matched to
327 void gencache_iterate(void (*fn)(const char* key, const char *value, time_t timeout, void* dptr),
328 void* data, const char* keystr_pattern)
330 TDB_LIST_NODE *node, *first_node;
332 char *keystr = NULL, *valstr = NULL, *entry = NULL;
337 /* fail completely if get null pointers passed */
338 SMB_ASSERT(fn && keystr_pattern);
340 if (!gencache_init()) return;
342 DEBUG(5, ("Searching cache keys with pattern %s\n", keystr_pattern));
343 node = tdb_search_keys(cache, keystr_pattern);
349 /* ensure null termination of the key string */
350 keystr = SMB_STRNDUP(node->node_key.dptr, node->node_key.dsize);
356 * We don't use gencache_get function, because we need to iterate through
357 * all of the entries. Validity verification is up to fn routine.
359 databuf = tdb_fetch(cache, node->node_key);
360 if (!databuf.dptr || databuf.dsize <= TIMEOUT_LEN) {
361 SAFE_FREE(databuf.dptr);
366 entry = SMB_STRNDUP(databuf.dptr, databuf.dsize);
368 SAFE_FREE(databuf.dptr);
373 SAFE_FREE(databuf.dptr);
375 valstr = SMB_MALLOC(databuf.dsize + 1 - TIMEOUT_LEN);
382 asprintf(&fmt, READ_CACHE_DATA_FMT_TEMPLATE, (unsigned int)databuf.dsize - TIMEOUT_LEN);
389 status = sscanf(entry, fmt, &u, valstr);
393 DEBUG(0,("gencache_iterate: invalid return from sscanf %d\n",status));
397 DEBUG(10, ("Calling function with arguments (key = %s, value = %s, timeout = %s)\n",
398 keystr, valstr, ctime(&timeout)));
399 fn(keystr, valstr, timeout, data);
407 tdb_search_list_free(first_node);
410 /********************************************************************
412 ********************************************************************/
414 int gencache_lock_entry( const char *key )
416 if (!gencache_init())
419 return tdb_lock_bystring(cache, key);
422 /********************************************************************
424 ********************************************************************/
426 void gencache_unlock_entry( const char *key )
428 if (!gencache_init())
431 tdb_unlock_bystring(cache, key);