/* 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 3 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, see <http://www.gnu.org/licenses/>. */ #include "includes.h" #undef DBGC_CLASS #define DBGC_CLASS DBGC_TDB #define TIMEOUT_LEN 12 #define CACHE_DATA_FMT "%12u/%s" #define READ_CACHE_DATA_FMT_TEMPLATE "%%12u/%%%us" #define BLOB_TYPE "DATA_BLOB" #define BLOB_TYPE_LEN 9 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; cache_fname = lock_path("gencache.tdb"); DEBUG(5, ("Opening cache file at %s\n", cache_fname)); cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT, O_RDWR|O_CREAT, 0644); if (!cache && (errno == EACCES)) { cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT, O_RDONLY, 0644); if (cache) { DEBUG(5, ("gencache_init: Opening cache file %s read-only.\n", cache_fname)); } } if (!cache) { DEBUG(5, ("Attempt to open gencache.tdb 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) { int ret; /* tdb_close routine returns -1 on error */ if (!cache) return False; DEBUG(5, ("Closing cache file\n")); ret = tdb_close(cache); cache = NULL; return ret != -1; } /** * Set an entry in the cache file. If there's no such * one, then add it. * * @param keystr string that represents a key of this entry * @param value text representation value being cached * @param timeout time when the value is expired * * @retval true when entry is successfuly stored * @retval false on failure **/ bool gencache_set(const char *keystr, const char *value, time_t timeout) { int ret; TDB_DATA 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); if (!valstr) return False; databuf = string_term_tdb_data(valstr); DEBUG(10, ("Adding cache entry with key = %s; value = %s and timeout =" " %s (%d seconds %s)\n", keystr, value,ctime(&timeout), (int)(timeout - time(NULL)), timeout > time(NULL) ? "ahead" : "in the past")); ret = tdb_store_bystring(cache, keystr, databuf, 0); SAFE_FREE(valstr); return ret == 0; } /** * Delete one entry from the cache file. * * @param keystr string that represents a key of this entry * * @retval true upon successful deletion * @retval false in case of failure **/ bool gencache_del(const char *keystr) { int ret; /* fail completely if get null pointers passed */ SMB_ASSERT(keystr); if (!gencache_init()) return False; DEBUG(10, ("Deleting cache entry (key = %s)\n", keystr)); ret = tdb_delete_bystring(cache, keystr); return ret == 0; } /** * Get existing entry from the cache file. * * @param keystr string that represents a key of this entry * @param valstr buffer that is allocated and filled with the entry value * buffer's disposing must be done outside * @param timeout pointer to a time_t that is filled with entry's * timeout * * @retval true when entry is successfuly fetched * @retval False for failure **/ bool gencache_get(const char *keystr, char **valstr, time_t *timeout) { TDB_DATA databuf; time_t t; char *endptr; /* fail completely if get null pointers passed */ SMB_ASSERT(keystr); if (!gencache_init()) { return False; } databuf = tdb_fetch_bystring(cache, keystr); if (databuf.dptr == NULL) { DEBUG(10, ("Cache entry with key = %s couldn't be found\n", keystr)); return False; } t = strtol((const char *)databuf.dptr, &endptr, 10); if ((endptr == NULL) || (*endptr != '/')) { DEBUG(2, ("Invalid gencache data format: %s\n", databuf.dptr)); SAFE_FREE(databuf.dptr); return False; } DEBUG(10, ("Returning %s cache entry: key = %s, value = %s, " "timeout = %s", t > time(NULL) ? "valid" : "expired", keystr, endptr+1, ctime(&t))); if (t <= time(NULL)) { /* We're expired, delete the entry */ tdb_delete_bystring(cache, keystr); SAFE_FREE(databuf.dptr); return False; } if (valstr) { *valstr = SMB_STRDUP(endptr+1); if (*valstr == NULL) { SAFE_FREE(databuf.dptr); DEBUG(0, ("strdup failed\n")); return False; } } SAFE_FREE(databuf.dptr); if (timeout) { *timeout = t; } return True; } /** * Get existing entry from the cache file. * * @param keystr string that represents a key of this entry * @param blob DATA_BLOB that is filled with entry's blob * @param expired pointer to a bool that indicates whether the entry is expired * * @retval true when entry is successfuly fetched * @retval False for failure **/ bool gencache_get_data_blob(const char *keystr, DATA_BLOB *blob, bool *expired) { TDB_DATA databuf; time_t t; char *blob_type; unsigned char *buf = NULL; bool ret = False; fstring valstr; int buflen = 0, len = 0, blob_len = 0; unsigned char *blob_buf = NULL; /* fail completely if get null pointers passed */ SMB_ASSERT(keystr); if (!gencache_init()) { return False; } databuf = tdb_fetch_bystring(cache, keystr); if (!databuf.dptr) { DEBUG(10,("Cache entry with key = %s couldn't be found\n", keystr)); return False; } buf = (unsigned char *)databuf.dptr; buflen = databuf.dsize; len += tdb_unpack(buf+len, buflen-len, "fB", &valstr, &blob_len, &blob_buf); if (len == -1) { goto out; } t = strtol(valstr, &blob_type, 10); if (strcmp(blob_type+1, BLOB_TYPE) != 0) { goto out; } DEBUG(10,("Returning %s cache entry: key = %s, " "timeout = %s", t > time(NULL) ? "valid" : "expired", keystr, ctime(&t))); if (t <= time(NULL)) { /* We're expired */ if (expired) { *expired = True; } } if (blob) { *blob = data_blob(blob_buf, blob_len); if (!blob->data) { goto out; } } ret = True; out: SAFE_FREE(blob_buf); SAFE_FREE(databuf.dptr); return ret; } /** * Set an entry in the cache file. If there's no such * one, then add it. * * @param keystr string that represents a key of this entry * @param blob DATA_BLOB value being cached * @param timeout time when the value is expired * * @retval true when entry is successfuly stored * @retval false on failure **/ bool gencache_set_data_blob(const char *keystr, DATA_BLOB *blob, time_t timeout) { bool ret = False; int tdb_ret; TDB_DATA databuf; char *valstr = NULL; unsigned char *buf = NULL; int len = 0, buflen = 0; /* fail completely if get null pointers passed */ SMB_ASSERT(keystr && blob); if (!gencache_init()) { return False; } asprintf(&valstr, "%12u/%s", (int)timeout, BLOB_TYPE); if (!valstr) { return False; } again: len = 0; len += tdb_pack(buf+len, buflen-len, "fB", valstr, blob->length, blob->data); if (len == -1) { goto out; } if (buflen < len) { SAFE_FREE(buf); buf = SMB_MALLOC_ARRAY(unsigned char, len); if (!buf) { goto out; } buflen = len; goto again; } databuf = make_tdb_data(buf, len); DEBUG(10,("Adding cache entry with key = %s; " "blob size = %d and timeout = %s" "(%d seconds %s)\n", keystr, (int)databuf.dsize, ctime(&timeout), (int)(timeout - time(NULL)), timeout > time(NULL) ? "ahead" : "in the past")); tdb_ret = tdb_store_bystring(cache, keystr, databuf, 0); if (tdb_ret == 0) { ret = True; } out: SAFE_FREE(valstr); SAFE_FREE(buf); return ret; } /** * 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 data void pointer to an arbitrary data that is passed directly to the fn * function on each call * @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, void* dptr), void* data, const char* keystr_pattern) { TDB_LIST_NODE *node, *first_node; TDB_DATA databuf; char *keystr = NULL, *valstr = NULL, *entry = NULL; time_t timeout = 0; int status; unsigned u; /* fail completely if get null pointers passed */ SMB_ASSERT(fn && keystr_pattern); if (!gencache_init()) return; DEBUG(5, ("Searching cache keys with pattern %s\n", keystr_pattern)); node = tdb_search_keys(cache, keystr_pattern); first_node = node; while (node) { char *fmt; /* ensure null termination of the key string */ keystr = SMB_STRNDUP((const char *)node->node_key.dptr, node->node_key.dsize); if (!keystr) { break; } /* * 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); if (!databuf.dptr || databuf.dsize <= TIMEOUT_LEN) { SAFE_FREE(databuf.dptr); SAFE_FREE(keystr); node = node->next; continue; } entry = SMB_STRNDUP((const char *)databuf.dptr, databuf.dsize); if (!entry) { SAFE_FREE(databuf.dptr); SAFE_FREE(keystr); break; } SAFE_FREE(databuf.dptr); valstr = (char *)SMB_MALLOC(databuf.dsize + 1 - TIMEOUT_LEN); if (!valstr) { SAFE_FREE(entry); SAFE_FREE(keystr); break; } asprintf(&fmt, READ_CACHE_DATA_FMT_TEMPLATE, (unsigned int)databuf.dsize - TIMEOUT_LEN); if (!fmt) { SAFE_FREE(valstr); SAFE_FREE(entry); SAFE_FREE(keystr); break; } status = sscanf(entry, fmt, &u, valstr); SAFE_FREE(fmt); if ( status != 2 ) { DEBUG(0,("gencache_iterate: invalid return from sscanf %d\n",status)); } timeout = u; DEBUG(10, ("Calling function with arguments (key = %s, value = %s, timeout = %s)\n", keystr, valstr, ctime(&timeout))); fn(keystr, valstr, timeout, data); SAFE_FREE(valstr); SAFE_FREE(entry); SAFE_FREE(keystr); node = node->next; } tdb_search_list_free(first_node); } /******************************************************************** lock a key ********************************************************************/ int gencache_lock_entry( const char *key ) { if (!gencache_init()) return -1; return tdb_lock_bystring(cache, key); } /******************************************************************** unlock a key ********************************************************************/ void gencache_unlock_entry( const char *key ) { if (!gencache_init()) return; tdb_unlock_bystring(cache, key); return; }