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Diffstat (limited to 'source3/lib/gencache.c')
| -rw-r--r-- | source3/lib/gencache.c | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/source3/lib/gencache.c b/source3/lib/gencache.c new file mode 100644 index 0000000000..9e2009ad4a --- /dev/null +++ b/source3/lib/gencache.c @@ -0,0 +1,319 @@ +/* + Unix SMB/CIFS implementation. + + Generic, persistent and shared between processes cache mechanism for use + by various parts of the Samba code + + Copyright (C) Rafal Szczesniak 2002 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include "includes.h" + +#undef DBGC_CLASS +#define DBGC_CLASS DBGC_TDB + +#define TIMEOUT_LEN 12 +#define CACHE_DATA_FMT "%12u/%s" + +static TDB_CONTEXT *cache; + +/** + * @file gencache.c + * @brief Generic, persistent and shared between processes cache mechanism + * for use by various parts of the Samba code + * + **/ + + +/** + * Cache initialisation function. Opens cache tdb file or creates + * it if does not exist. + * + * @return true on successful initialisation of the cache or + * false on failure + **/ + +BOOL gencache_init(void) +{ + char* cache_fname = NULL; + + /* skip file open if it's already opened */ + if (cache) return True; + + asprintf(&cache_fname, "%s/%s", lp_lockdir(), "gencache.tdb"); + if (cache_fname) + DEBUG(5, ("Opening cache file at %s\n", cache_fname)); + else { + DEBUG(0, ("Filename allocation failed.\n")); + return False; + } + + cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT, + O_RDWR|O_CREAT, 0644); + + SAFE_FREE(cache_fname); + if (!cache) { + DEBUG(0, ("Attempt to open the cache file has failed.\n")); + return False; + } + return True; +} + + +/** + * Cache shutdown function. Closes opened cache tdb file. + * + * @return true on successful closing the cache or + * false on failure during cache shutdown + **/ + +BOOL gencache_shutdown(void) +{ + /* tdb_close routine returns 0 on successful close */ + if (!cache) return False; + DEBUG(5, ("Closing cache file\n")); + return tdb_close(cache) ? False : True; +} + + +/** + * Add one entry to the cache file. + * (it part of tridge's proposed API) + * + * @param key string that represents a key of this entry + * @param value text representation value being cached + * @param timeout time when the value is expired + * + * @return true when entry is successfuly stored or + * false on the attempt's failure + **/ + +BOOL gencache_add(const char *keystr, const char *value, time_t timeout) +{ + int ret; + TDB_DATA keybuf, databuf; + char* valstr = NULL; + + /* fail completely if get null pointers passed */ + SMB_ASSERT(keystr && value); + + if (!gencache_init()) return False; + + asprintf(&valstr, CACHE_DATA_FMT, (int)timeout, value); + keybuf.dptr = strdup(keystr); + keybuf.dsize = strlen(keystr); + databuf.dptr = strdup(valstr); + databuf.dsize = strlen(valstr); + DEBUG(10, ("Adding cache entry with key = %s; value = %s and timeout \ + = %s (%d seconds %s)\n", keybuf.dptr, value, ctime(&timeout), + (int)(timeout - time(NULL)), timeout > time(NULL) ? "ahead" : "in the past")); + + ret = tdb_store(cache, keybuf, databuf, TDB_INSERT); + SAFE_FREE(valstr); + SAFE_FREE(keybuf.dptr); + SAFE_FREE(databuf.dptr); + + return ret == 0 ? True : False; +} + + +/** + * Set existing entry to the cache file. + * (it part of tridge's proposed API) + * + * @param key string that represents a key of this entry + * @param value text representation value being cached + * @param timeout time when the value is expired + * + * @return true when entry is successfuly set or + * false on the attempt's failure + **/ + +BOOL gencache_set(const char *keystr, const char *valstr, time_t timeout) +{ + int ret = -1; + TDB_DATA keybuf, databuf; + char *old_valstr, *datastr; + time_t old_timeout; + + /* fail completely if get null pointers passed */ + SMB_ASSERT(keystr && valstr); + + if (!gencache_init()) return False; + + /* + * Check whether entry exists in the cache + * Don't verify gencache_get exit code, since the entry may be expired + */ + gencache_get(keystr, &old_valstr, &old_timeout); + + if (!(old_valstr && old_timeout)) return False; + + DEBUG(10, ("Setting cache entry with key = %s; old value = %s and old timeout \ + = %s\n", keystr, old_valstr, ctime(&old_timeout))); + + asprintf(&datastr, CACHE_DATA_FMT, (int)timeout, valstr); + keybuf.dptr = strdup(keystr); + keybuf.dsize = strlen(keystr); + databuf.dptr = strdup(datastr); + databuf.dsize = strlen(datastr); + DEBUGADD(10, ("New value = %s, new timeout = %s (%d seconds %s)", valstr, + ctime(&timeout), (int)(timeout - time(NULL)), + timeout > time(NULL) ? "ahead" : "in the past")); + + + ret = tdb_store(cache, keybuf, databuf, TDB_REPLACE); + + SAFE_FREE(datastr); + SAFE_FREE(old_valstr); + SAFE_FREE(keybuf.dptr); + SAFE_FREE(databuf.dptr); + + return ret == 0 ? True : False; +} + + +/** + * Delete one entry from the cache file. + * (it part of tridge's proposed API) + * + * @param key string that represents a key of this entry + * + * @return true upon successful deletion or + * false in case of failure + **/ + +BOOL gencache_del(const char *keystr) +{ + int ret; + TDB_DATA keybuf; + + /* fail completely if get null pointers passed */ + SMB_ASSERT(keystr); + + if (!gencache_init()) return False; + + keybuf.dptr = strdup(keystr); + keybuf.dsize = strlen(keystr); + DEBUG(10, ("Deleting cache entry (key = %s)\n", keystr)); + ret = tdb_delete(cache, keybuf); + + SAFE_FREE(keybuf.dptr); + return ret == 0 ? True : False; +} + + +/** + * Get existing entry from the cache file. + * (it part of tridge's proposed API) + * + * @param key string that represents a key of this entry + * @param value buffer that is allocated and filled with the entry value + * buffer's disposing is done outside + * @param timeout pointer to a time_t that is filled with entry's + * timeout + * + * @return true when entry is successfuly fetched or + * false on the failure + **/ + +BOOL gencache_get(const char *keystr, char **valstr, time_t *timeout) +{ + TDB_DATA keybuf, databuf; + + /* fail completely if get null pointers passed */ + SMB_ASSERT(keystr && valstr && timeout); + + if (!gencache_init()) return False; + + keybuf.dptr = strdup(keystr); + keybuf.dsize = strlen(keystr); + databuf = tdb_fetch(cache, keybuf); + + if (databuf.dptr) { + char* entry_buf = strndup(databuf.dptr, databuf.dsize); + *valstr = (char*)malloc(sizeof(char) * (databuf.dsize - TIMEOUT_LEN)); + + sscanf(entry_buf, CACHE_DATA_FMT, (int*)timeout, *valstr); + SAFE_FREE(entry_buf); + + DEBUG(10, ("Returning %s cache entry: key = %s, value = %s, timeout = %s\n", + *timeout > time(NULL) ? "valid" : "expired", keystr, *valstr, + ctime(timeout))); + return *timeout > time(NULL); + } else { + *valstr = NULL; + timeout = NULL; + DEBUG(10, ("Cache entry with key = %s couldn't be found\n", keystr)); + return False; + } +} + + +/** + * Iterate through all entries which key matches to specified pattern + * + * @param fn pointer to the function that will be supplied with each single + * matching cache entry (key, value and timeout) as an arguments + * @param keystr_pattern pattern the existing entries' keys are matched to + * + **/ + +void gencache_iterate(void (*fn)(const char* key, const char *value, time_t timeout), + const char* keystr_pattern) +{ + TDB_LIST_NODE *node, *first_node; + TDB_DATA databuf; + char *keystr = NULL, *valstr = NULL, *entry = NULL; + time_t timeout = 0; + + /* fail completely if get null pointers passed */ + SMB_ASSERT(fn && keystr_pattern); + + if (!gencache_init()) return; + + DEBUG(5, ("Searching cache keys with pattern %s", keystr_pattern)); + node = tdb_search_keys(cache, keystr_pattern); + first_node = node; + + while (node) { + /* ensure null termination of the key string */ + node->node_key.dptr[node->node_key.dsize] = '\0'; + keystr = node->node_key.dptr; + + /* + * We don't use gencache_get function, because we need to iterate through + * all of the entries. Validity verification is up to fn routine. + */ + databuf = tdb_fetch(cache, node->node_key); + entry = strndup(databuf.dptr, databuf.dsize); + valstr = (char*)malloc(sizeof(char) * (databuf.dsize - TIMEOUT_LEN)); + sscanf(entry, CACHE_DATA_FMT, (int*)(&timeout), valstr); + + DEBUG(10, ("Calling function with arguments (key = %s, value = %s, timeout = %s)\n", + keystr, valstr, ctime(&timeout))); + fn(keystr, valstr, timeout); + + SAFE_FREE(valstr); + SAFE_FREE(entry); + node = node->next; + } + + tdb_search_list_free(first_node); +} + + |