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
= SMB_STRDUP(keystr
);
121 keybuf
.dsize
= strlen(keystr
)+1;
122 databuf
.dptr
= SMB_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
= SMB_STRDUP(keystr
);
174 keybuf
.dsize
= strlen(keystr
)+1;
175 databuf
.dptr
= SMB_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
= SMB_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
= SMB_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
= SMB_STRNDUP(databuf
.dptr
, databuf
.dsize
);
255 v
= SMB_MALLOC(databuf
.dsize
- TIMEOUT_LEN
);
257 SAFE_FREE(databuf
.dptr
);
258 sscanf(entry_buf
, CACHE_DATA_FMT
, (int*)&t
, v
);
259 SAFE_FREE(entry_buf
);
261 DEBUG(10, ("Returning %s cache entry: key = %s, value = %s, "
262 "timeout = %s\n", t
> time(NULL
) ? "valid" :
263 "expired", keystr
, v
, ctime(&t
)));
273 return t
> time(NULL
);
276 SAFE_FREE(databuf
.dptr
);
284 DEBUG(10, ("Cache entry with key = %s couldn't be found\n",
293 * Iterate through all entries which key matches to specified pattern
295 * @param fn pointer to the function that will be supplied with each single
296 * matching cache entry (key, value and timeout) as an arguments
297 * @param data void pointer to an arbitrary data that is passed directly to the fn
298 * function on each call
299 * @param keystr_pattern pattern the existing entries' keys are matched to
303 void gencache_iterate(void (*fn
)(const char* key
, const char *value
, time_t timeout
, void* dptr
),
304 void* data
, const char* keystr_pattern
)
306 TDB_LIST_NODE
*node
, *first_node
;
308 char *keystr
= NULL
, *valstr
= NULL
, *entry
= NULL
;
311 /* fail completely if get null pointers passed */
312 SMB_ASSERT(fn
&& keystr_pattern
);
314 if (!gencache_init()) return;
316 DEBUG(5, ("Searching cache keys with pattern %s\n", keystr_pattern
));
317 node
= tdb_search_keys(cache
, keystr_pattern
);
321 /* ensure null termination of the key string */
322 keystr
= SMB_STRNDUP(node
->node_key
.dptr
, node
->node_key
.dsize
);
325 * We don't use gencache_get function, because we need to iterate through
326 * all of the entries. Validity verification is up to fn routine.
328 databuf
= tdb_fetch(cache
, node
->node_key
);
329 if (!databuf
.dptr
|| databuf
.dsize
<= TIMEOUT_LEN
) {
330 SAFE_FREE(databuf
.dptr
);
335 entry
= SMB_STRNDUP(databuf
.dptr
, databuf
.dsize
);
336 SAFE_FREE(databuf
.dptr
);
337 valstr
= SMB_MALLOC(databuf
.dsize
- TIMEOUT_LEN
);
338 sscanf(entry
, CACHE_DATA_FMT
, (int*)(&timeout
), valstr
);
340 DEBUG(10, ("Calling function with arguments (key = %s, value = %s, timeout = %s)\n",
341 keystr
, valstr
, ctime(&timeout
)));
342 fn(keystr
, valstr
, timeout
, data
);
350 tdb_search_list_free(first_node
);
353 /********************************************************************
355 ********************************************************************/
357 int gencache_lock_entry( const char *key
)
359 if (!gencache_init())
362 return tdb_lock_bystring(cache
, key
, 0);
365 /********************************************************************
367 ********************************************************************/
369 void gencache_unlock_entry( const char *key
)
371 if (!gencache_init())
374 tdb_unlock_bystring(cache
, key
);