2007-07-31 16:44:25 +00:00
|
|
|
/*
|
|
|
|
* 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(¤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 =
|
2007-07-31 18:50:06 +00:00
|
|
|
"Unlocks a previously locked mutex. Note that it is generally unnecessary to\n"
|
|
|
|
"unlock in a hangup routine, as any lock held is automatically freed when the\n"
|
|
|
|
"channel is destroyed. Returns 1 if the channel had a lock or 0 otherwise.\n",
|
2007-07-31 16:44:25 +00:00
|
|
|
.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");
|