Add func_lock, which creates dialplan mutexes, and note that the Macro apps are now...
authorTilghman Lesher <tilghman@meg.abyt.es>
Tue, 31 Jul 2007 16:44:25 +0000 (16:44 +0000)
committerTilghman Lesher <tilghman@meg.abyt.es>
Tue, 31 Jul 2007 16:44:25 +0000 (16:44 +0000)
(Closes issue #10264)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@77834 65c4cc65-6c06-0410-ace0-fbb531ad65f3

UPGRADE.txt
funcs/func_lock.c [new file with mode: 0644]

index 16b1777..034ecaf 100644 (file)
@@ -71,6 +71,11 @@ Applications:
 * 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:
 
diff --git a/funcs/func_lock.c b/funcs/func_lock.c
new file mode 100644 (file)
index 0000000..477f1c1
--- /dev/null
@@ -0,0 +1,247 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2007, Tilghman Lesher
+ *
+ * Tilghman Lesher <func_lock_2007@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@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(&current->mutex);
+               AST_LIST_INSERT_TAIL(&locklist, current, entries);
+       }
+
+       res = try ? ast_mutex_trylock(&current->mutex) : ast_mutex_lock(&current->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(&current->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(&current->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");