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-rw-r--r--source4/lib/gencache.c372
1 files changed, 372 insertions, 0 deletions
diff --git a/source4/lib/gencache.c b/source4/lib/gencache.c
new file mode 100644
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--- /dev/null
+++ b/source4/lib/gencache.c
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+/*
+ 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(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)
+{
+ /* tdb_close routine returns -1 on error */
+ if (!cache) return False;
+ DEBUG(5, ("Closing cache file\n"));
+ return tdb_close(cache) != -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 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);
+ if (!valstr)
+ return False;
+
+ keybuf.dptr = strdup(keystr);
+ keybuf.dsize = strlen(keystr)+1;
+ databuf.dptr = strdup(valstr);
+ databuf.dsize = strlen(valstr)+1;
+ 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, 0);
+ SAFE_FREE(valstr);
+ SAFE_FREE(keybuf.dptr);
+ SAFE_FREE(databuf.dptr);
+
+ return ret == 0;
+}
+
+
+/**
+ * Set existing entry to the cache file.
+ *
+ * @param keystr string that represents a key of this entry
+ * @param valstr text representation value being cached
+ * @param timeout time when the value is expired
+ *
+ * @retval true when entry is successfuly set
+ * @retval false on failure
+ **/
+
+BOOL gencache_set_only(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)+1;
+ databuf.dptr = strdup(datastr);
+ databuf.dsize = strlen(datastr)+1;
+ 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;
+}
+
+
+/**
+ * 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;
+ 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)+1;
+ DEBUG(10, ("Deleting cache entry (key = %s)\n", keystr));
+ ret = tdb_delete(cache, keybuf);
+
+ SAFE_FREE(keybuf.dptr);
+ 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 keybuf, databuf;
+
+ /* fail completely if get null pointers passed */
+ SMB_ASSERT(keystr);
+
+ if (!gencache_init())
+ return False;
+
+ keybuf.dptr = strdup(keystr);
+ keybuf.dsize = strlen(keystr)+1;
+ databuf = tdb_fetch(cache, keybuf);
+ SAFE_FREE(keybuf.dptr);
+
+ if (databuf.dptr && databuf.dsize > TIMEOUT_LEN) {
+ char* entry_buf = strndup(databuf.dptr, databuf.dsize);
+ char *v;
+ time_t t;
+
+ v = (char*)malloc(sizeof(char) *
+ (databuf.dsize - TIMEOUT_LEN));
+
+ SAFE_FREE(databuf.dptr);
+ sscanf(entry_buf, CACHE_DATA_FMT, (int*)&t, v);
+ SAFE_FREE(entry_buf);
+
+ DEBUG(10, ("Returning %s cache entry: key = %s, value = %s, "
+ "timeout = %s\n", t > time(NULL) ? "valid" :
+ "expired", keystr, v, ctime(&t)));
+
+ if (valstr)
+ *valstr = v;
+ else
+ SAFE_FREE(v);
+
+ if (timeout)
+ *timeout = t;
+
+ return t > time(NULL);
+
+ } else {
+ SAFE_FREE(databuf.dptr);
+
+ if (valstr)
+ *valstr = NULL;
+
+ if (timeout)
+ 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 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;
+
+ /* 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) {
+ /* ensure null termination of the key string */
+ keystr = strndup(node->node_key.dptr, node->node_key.dsize);
+
+ /*
+ * 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 = strndup(databuf.dptr, databuf.dsize);
+ SAFE_FREE(databuf.dptr);
+ 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, 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 )
+{
+ return tdb_lock_bystring(cache, key, 0);
+}
+
+/********************************************************************
+ unlock a key
+********************************************************************/
+
+void gencache_unlock_entry( const char *key )
+{
+ tdb_unlock_bystring(cache, key);
+ return;
+}
+
+
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