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"
32 static TDB_CONTEXT *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_open_log(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 /* tdb_close routine returns -1 on error */
87 if (!cache) return False;
88 DEBUG(5, ("Closing cache file\n"));
89 return tdb_close(cache) != -1;
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 = strdup(keystr);
121 keybuf.dsize = strlen(keystr)+1;
122 databuf.dptr = 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)),
127 timeout > time(NULL) ? "ahead" : "in the past"));
129 ret = tdb_store(cache, keybuf, databuf, 0);
131 SAFE_FREE(keybuf.dptr);
132 SAFE_FREE(databuf.dptr);
139 * Set existing entry to the cache file.
141 * @param keystr string that represents a key of this entry
142 * @param valstr text representation value being cached
143 * @param timeout time when the value is expired
145 * @retval true when entry is successfuly set
146 * @retval false on failure
149 BOOL gencache_set_only(const char *keystr, const char *valstr, time_t timeout)
152 TDB_DATA keybuf, databuf;
153 char *old_valstr, *datastr;
156 /* fail completely if get null pointers passed */
157 SMB_ASSERT(keystr && valstr);
159 if (!gencache_init()) return False;
162 * Check whether entry exists in the cache
163 * Don't verify gencache_get exit code, since the entry may be expired
165 gencache_get(keystr, &old_valstr, &old_timeout);
167 if (!(old_valstr && old_timeout)) return False;
169 DEBUG(10, ("Setting cache entry with key = %s; old value = %s and old timeout \
170 = %s\n", keystr, old_valstr, ctime(&old_timeout)));
172 asprintf(&datastr, CACHE_DATA_FMT, (int)timeout, valstr);
173 keybuf.dptr = strdup(keystr);
174 keybuf.dsize = strlen(keystr)+1;
175 databuf.dptr = strdup(datastr);
176 databuf.dsize = strlen(datastr)+1;
177 DEBUGADD(10, ("New value = %s, new timeout = %s (%d seconds %s)", valstr,
178 ctime(&timeout), (int)(timeout - time(NULL)),
179 timeout > time(NULL) ? "ahead" : "in the past"));
182 ret = tdb_store(cache, keybuf, databuf, TDB_REPLACE);
185 SAFE_FREE(old_valstr);
186 SAFE_FREE(keybuf.dptr);
187 SAFE_FREE(databuf.dptr);
194 * Delete one entry from the cache file.
196 * @param keystr string that represents a key of this entry
198 * @retval true upon successful deletion
199 * @retval false in case of failure
202 BOOL gencache_del(const char *keystr)
207 /* fail completely if get null pointers passed */
210 if (!gencache_init()) return False;
212 keybuf.dptr = strdup(keystr);
213 keybuf.dsize = strlen(keystr)+1;
214 DEBUG(10, ("Deleting cache entry (key = %s)\n", keystr));
215 ret = tdb_delete(cache, keybuf);
217 SAFE_FREE(keybuf.dptr);
223 * Get existing entry from the cache file.
225 * @param keystr string that represents a key of this entry
226 * @param valstr buffer that is allocated and filled with the entry value
227 * buffer's disposing must be done outside
228 * @param timeout pointer to a time_t that is filled with entry's
231 * @retval true when entry is successfuly fetched
232 * @retval False for failure
235 BOOL gencache_get(const char *keystr, char **valstr, time_t *timeout)
237 TDB_DATA keybuf, databuf;
239 /* fail completely if get null pointers passed */
242 if (!gencache_init())
245 keybuf.dptr = strdup(keystr);
246 keybuf.dsize = strlen(keystr)+1;
247 databuf = tdb_fetch(cache, keybuf);
248 SAFE_FREE(keybuf.dptr);
250 if (databuf.dptr && databuf.dsize > TIMEOUT_LEN) {
251 char* entry_buf = strndup(databuf.dptr, databuf.dsize);
255 v = (char*)malloc(sizeof(char) *
256 (databuf.dsize - TIMEOUT_LEN));
258 SAFE_FREE(databuf.dptr);
259 sscanf(entry_buf, CACHE_DATA_FMT, (int*)&t, v);
260 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;
312 /* fail completely if get null pointers passed */
313 SMB_ASSERT(fn && keystr_pattern);
315 if (!gencache_init()) return;
317 DEBUG(5, ("Searching cache keys with pattern %s\n", keystr_pattern));
318 node = tdb_search_keys(cache, keystr_pattern);
322 /* ensure null termination of the key string */
323 keystr = strndup(node->node_key.dptr, node->node_key.dsize);
326 * We don't use gencache_get function, because we need to iterate through
327 * all of the entries. Validity verification is up to fn routine.
329 databuf = tdb_fetch(cache, node->node_key);
330 if (!databuf.dptr || databuf.dsize <= TIMEOUT_LEN) {
331 SAFE_FREE(databuf.dptr);
336 entry = strndup(databuf.dptr, databuf.dsize);
337 SAFE_FREE(databuf.dptr);
338 valstr = (char*)malloc(sizeof(char) * (databuf.dsize - TIMEOUT_LEN));
339 sscanf(entry, CACHE_DATA_FMT, (int*)(&timeout), valstr);
341 DEBUG(10, ("Calling function with arguments (key = %s, value = %s, timeout = %s)\n",
342 keystr, valstr, ctime(&timeout)));
343 fn(keystr, valstr, timeout, data);
351 tdb_search_list_free(first_node);
354 /********************************************************************
356 ********************************************************************/
358 int gencache_lock_entry( const char *key )
360 if (!gencache_init())
363 return tdb_lock_bystring(cache, key, 0);
366 /********************************************************************
368 ********************************************************************/
370 void gencache_unlock_entry( const char *key )
372 if (!gencache_init())
375 tdb_unlock_bystring(cache, key);