added gencache implementation from mimir - thanks!

1 files changed, 319 insertions, 0 deletions

diff --git a/source/lib/gencache.c b/source/lib/gencache.c
new file mode 100644
index 00000000000..9e2009ad4a6
--- /dev/null
+++ b/source/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);
+}
+
+