[asterisk-commits] tilghman: trunk r77834 - in /trunk: UPGRADE.txt funcs/func_lock.c
SVN commits to the Asterisk project
asterisk-commits at lists.digium.com
Tue Jul 31 11:44:25 CDT 2007
Author: tilghman
Date: Tue Jul 31 11:44:25 2007
New Revision: 77834
URL: http://svn.digium.com/view/asterisk?view=rev&rev=77834
Log:
Add func_lock, which creates dialplan mutexes, and note that the Macro apps are now deprecated.
(Closes issue #10264)
Added:
trunk/funcs/func_lock.c (with props)
Modified:
trunk/UPGRADE.txt
Modified: trunk/UPGRADE.txt
URL: http://svn.digium.com/view/asterisk/trunk/UPGRADE.txt?view=diff&rev=77834&r1=77833&r2=77834
==============================================================================
--- trunk/UPGRADE.txt (original)
+++ trunk/UPGRADE.txt Tue Jul 31 11:44:25 2007
@@ -71,6 +71,11 @@
* DISA()'s fifth argument is now an options argument. If you have previously
used 'NOANSWER' in this argument, you'll need to convert that to the new
option 'n'.
+* Macro() is now deprecated. If you need subroutines, you should use the
+ Gosub()/Return() applications. To replace MacroExclusive(), we have
+ introduced dialplan functions LOCK(), TRYLOCK(), and UNLOCK(). You may use
+ these functions in any location where you desire to ensure that only one
+ channel is executing that path at any one time.
CDR:
Added: trunk/funcs/func_lock.c
URL: http://svn.digium.com/view/asterisk/trunk/funcs/func_lock.c?view=auto&rev=77834
==============================================================================
--- trunk/funcs/func_lock.c (added)
+++ trunk/funcs/func_lock.c Tue Jul 31 11:44:25 2007
@@ -1,0 +1,247 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2007, Tilghman Lesher
+ *
+ * Tilghman Lesher <func_lock_2007 at the-tilghman.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ *
+ * \brief Dialplan mutexes
+ *
+ * \author Tilghman Lesher <func_lock_2007 at the-tilghman.com>
+ *
+ * \ingroup functions
+ *
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "asterisk/lock.h"
+#include "asterisk/file.h"
+#include "asterisk/logger.h"
+#include "asterisk/options.h"
+#include "asterisk/channel.h"
+#include "asterisk/pbx.h"
+#include "asterisk/module.h"
+#include "asterisk/options.h"
+#include "asterisk/linkedlists.h"
+
+AST_LIST_HEAD_STATIC(locklist, lock_frame);
+
+static void lock_free(void *data);
+static int unloading = 0;
+
+static struct ast_datastore_info lock_info = {
+ .type = "MUTEX",
+ .destroy = lock_free,
+};
+
+struct lock_frame {
+ AST_LIST_ENTRY(lock_frame) entries;
+ ast_mutex_t mutex;
+ struct ast_channel *channel;
+ char name[0];
+};
+
+static void lock_free(void *data)
+{
+ struct lock_frame *frame = data;
+ if (!frame)
+ return;
+ frame->channel = NULL;
+ ast_mutex_unlock(&frame->mutex);
+}
+
+static int get_lock(struct ast_channel *chan, char *lockname, int try)
+{
+ struct ast_datastore *lock_store = ast_channel_datastore_find(chan, &lock_info, NULL);
+ struct lock_frame *current;
+ int res;
+
+ if (!lock_store) {
+ ast_debug(1, "Channel %s has no lock datastore, so we're allocating one.\n", chan->name);
+ lock_store = ast_channel_datastore_alloc(&lock_info, NULL);
+ if (!lock_store) {
+ ast_log(LOG_ERROR, "Unable to allocate new datastore. No locks will be obtained.\n");
+ return -1;
+ }
+ ast_channel_datastore_add(chan, lock_store);
+ }
+
+ /* If the channel already has a lock, then free the existing lock */
+ if (lock_store->data) {
+ struct lock_frame *old = lock_store->data;
+ old->channel = NULL;
+ ast_mutex_unlock(&old->mutex);
+ }
+
+ /* Lock already exist? */
+ AST_LIST_LOCK(&locklist);
+ AST_LIST_TRAVERSE(&locklist, current, entries) {
+ if (strcmp(current->name, lockname) == 0) {
+ break;
+ }
+ }
+
+ if (!current) {
+ if (unloading) {
+ /* Don't bother */
+ AST_LIST_UNLOCK(&locklist);
+ return -1;
+ }
+
+ /* Create new lock entry */
+ current = ast_calloc(1, sizeof(*current) + strlen(lockname) + 1);
+ if (!current) {
+ AST_LIST_UNLOCK(&locklist);
+ return -1;
+ }
+
+ strcpy((char *)current + sizeof(*current), lockname);
+ ast_mutex_init(¤t->mutex);
+ AST_LIST_INSERT_TAIL(&locklist, current, entries);
+ }
+
+ res = try ? ast_mutex_trylock(¤t->mutex) : ast_mutex_lock(¤t->mutex);
+ if (res == 0) {
+ lock_store->data = current;
+ current->channel = chan;
+ }
+
+ AST_LIST_UNLOCK(&locklist);
+ return res;
+}
+
+static int unlock_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
+{
+ struct ast_datastore *lock_store = ast_channel_datastore_find(chan, &lock_info, NULL);
+ struct lock_frame *current;
+
+ if (!lock_store) {
+ ast_log(LOG_WARNING, "No datastore for dialplan locks. Nothing was ever locked!\n");
+ ast_copy_string(buf, "0", len);
+ return 0;
+ }
+
+ current = lock_store->data;
+
+ if (!current) {
+ ast_copy_string(buf, "0", len);
+ return 0;
+ }
+
+ current->channel = NULL;
+ ast_mutex_unlock(¤t->mutex);
+ ast_copy_string(buf, "1", len);
+ return 0;
+}
+
+static int lock_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
+{
+ ast_copy_string(buf, get_lock(chan, data, 0) ? "0" : "1", len);
+ return 0;
+}
+
+static int trylock_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
+{
+ ast_copy_string(buf, get_lock(chan, data, 1) ? "0" : "1", len);
+ return 0;
+}
+
+static struct ast_custom_function lock_function = {
+ .name = "LOCK",
+ .synopsis = "Attempt to obtain a named mutex",
+ .desc =
+"Attempts to grab a named lock exclusively, and prevents other channels\n"
+"from obtaining the same lock. LOCK will wait for the lock to become\n"
+"available. Returns 1 if the lock was obtained or 0 on error.\n\n"
+"Note: to avoid the possibility of a deadlock, LOCK will only attempt to\n"
+"grab a single lock. If you have a lock already and you attempt to lock\n"
+"another name, LOCK will unlock the first name before attempting to lock\n"
+"the second name.\n",
+ .syntax = "LOCK(<lockname>)",
+ .read = lock_read,
+};
+
+static struct ast_custom_function trylock_function = {
+ .name = "TRYLOCK",
+ .synopsis = "Attempt to obtain a named mutex",
+ .desc =
+"Attempts to grab a named lock exclusively, and prevents other channels\n"
+"from obtaining the same lock. Returns 1 if the lock was available or 0\n"
+"otherwise.\n\n"
+"Note: to avoid the possibility of a deadlock, TRYLOCK will only attempt to\n"
+"grab a single lock. If you have a lock already and you attempt to lock\n"
+"another name, TRYLOCK will unlock the first name before attempting to lock\n"
+"the second name.\n",
+ .syntax = "TRYLOCK(<lockname>)",
+ .read = trylock_read,
+};
+
+static struct ast_custom_function unlock_function = {
+ .name = "UNLOCK",
+ .synopsis = "Unlocks a named mutex",
+ .desc =
+"Unlocks a previously locked mutex. Returns 1 if the channel had a lock\n"
+"or 0 otherwise.\n",
+ .syntax = "UNLOCK()",
+ .read = unlock_read,
+};
+
+static int unload_module(void)
+{
+ struct lock_frame *current;
+
+ /* Module flag */
+ unloading = 1;
+
+ AST_LIST_LOCK(&locklist);
+ while ((current = AST_LIST_REMOVE_HEAD(&locklist, entries))) {
+ /* If any locks are currently in use, then we cannot unload this module */
+ if (current->channel) {
+ /* Put it back */
+ AST_LIST_INSERT_HEAD(&locklist, current, entries);
+ AST_LIST_UNLOCK(&locklist);
+ unloading = 0;
+ return -1;
+ }
+ ast_mutex_destroy(¤t->mutex);
+ ast_free(current);
+ }
+
+ /* No locks left, unregister functions */
+ ast_custom_function_unregister(&lock_function);
+ ast_custom_function_unregister(&trylock_function);
+ ast_custom_function_unregister(&unlock_function);
+
+ AST_LIST_UNLOCK(&locklist);
+ return 0;
+}
+
+static int load_module(void)
+{
+ int res = ast_custom_function_register(&lock_function);
+ res |= ast_custom_function_register(&trylock_function);
+ res |= ast_custom_function_register(&unlock_function);
+ return res;
+}
+
+AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Dialplan mutexes");
Propchange: trunk/funcs/func_lock.c
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