asterisk/main/autoservice.c

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.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 Automatic channel service routines
 *
 * \author Mark Spencer <markster@digium.com> 
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include <sys/time.h>
#include <signal.h>

#include "asterisk/pbx.h"
#include "asterisk/frame.h"
#include "asterisk/sched.h"
#include "asterisk/channel.h"
#include "asterisk/file.h"
#include "asterisk/translate.h"
#include "asterisk/manager.h"
#include "asterisk/chanvars.h"
#include "asterisk/linkedlists.h"
#include "asterisk/indications.h"
#include "asterisk/lock.h"
#include "asterisk/utils.h"

#define MAX_AUTOMONS 256

struct asent {
	struct ast_channel *chan;
	/*! This gets incremented each time autoservice gets started on the same
	 *  channel.  It will ensure that it doesn't actually get stopped until 
	 *  it gets stopped for the last time. */
	unsigned int use_count;
	AST_LIST_HEAD_NOLOCK(, ast_frame) dtmf_frames;
	AST_LIST_ENTRY(asent) list;
};

static AST_RWLIST_HEAD_STATIC(aslist, asent);

static pthread_t asthread = AST_PTHREADT_NULL;

static void defer_frame(struct ast_channel *chan, struct ast_frame *f)
{
	struct ast_frame *dup_f;
	struct asent *as;

	AST_RWLIST_WRLOCK(&aslist);
	AST_RWLIST_TRAVERSE(&aslist, as, list) {
		if (as->chan != chan)
			continue;
		if ((dup_f = ast_frdup(f)))
			AST_LIST_INSERT_TAIL(&as->dtmf_frames, dup_f, frame_list);
	}
	AST_RWLIST_UNLOCK(&aslist);
}

static void *autoservice_run(void *ign)
{
	for (;;) {
		struct ast_channel *mons[MAX_AUTOMONS], *chan;
		struct asent *as;
		int x = 0, ms = 500;

		AST_RWLIST_RDLOCK(&aslist);
		AST_RWLIST_TRAVERSE(&aslist, as, list) {
			if (!ast_check_hangup(as->chan)) {
				if (x < MAX_AUTOMONS)
					mons[x++] = as->chan;
				else
					ast_log(LOG_WARNING, "Exceeded maximum number of automatic monitoring events.  Fix autoservice.c\n");
			}
		}
		AST_RWLIST_UNLOCK(&aslist);

		if ((chan = ast_waitfor_n(mons, x, &ms))) {
			struct ast_frame *f = ast_read(chan);
	
			if (!f) {
				struct ast_frame hangup_frame = { 0, };
				/* No frame means the channel has been hung up.
				 * A hangup frame needs to be queued here as ast_waitfor() may
				 * never return again for the condition to be detected outside
				 * of autoservice.  So, we'll leave a HANGUP queued up so the
				 * thread in charge of this channel will know. */

				hangup_frame.frametype = AST_FRAME_CONTROL;
				hangup_frame.subclass = AST_CONTROL_HANGUP;

				defer_frame(chan, &hangup_frame);

				continue;
			}
			
			/* Do not add a default entry in this switch statement.  Each new
			 * frame type should be addressed directly as to whether it should
			 * be queued up or not. */
			switch (f->frametype) {
			/* Save these frames */
			case AST_FRAME_DTMF_BEGIN:
			case AST_FRAME_DTMF_END:
			case AST_FRAME_CONTROL:
			case AST_FRAME_TEXT:
			case AST_FRAME_IMAGE:
			case AST_FRAME_HTML:
				defer_frame(chan, f);
				break;

			/* Throw these frames away */
			case AST_FRAME_VOICE:
			case AST_FRAME_VIDEO:
			case AST_FRAME_NULL:
			case AST_FRAME_IAX:
			case AST_FRAME_CNG:
			case AST_FRAME_MODEM:
				break;
			}

			if (f)
				ast_frfree(f);
		}
	}

	asthread = AST_PTHREADT_NULL;

	return NULL;
}

int ast_autoservice_start(struct ast_channel *chan)
{
	int res = 0;
	struct asent *as;

	AST_RWLIST_WRLOCK(&aslist);

	/* Check if the channel already has autoservice */
	AST_RWLIST_TRAVERSE(&aslist, as, list) {
		if (as->chan == chan) {
			as->use_count++;
			break;
		}
	}

	/* If not, start autoservice on channel */
	if (as) {
		/* Entry extist, autoservice is already handling this channel */
	} else if ((as = ast_calloc(1, sizeof(*as))) == NULL) {
		/* Memory allocation failed */
		res = -1;
	} else {
		/* New entry created */
		as->chan = chan;
		as->use_count = 1;
		AST_RWLIST_INSERT_HEAD(&aslist, as, list);
		if (asthread == AST_PTHREADT_NULL) { /* need start the thread */
			if (ast_pthread_create_background(&asthread, NULL, autoservice_run, NULL)) {
				ast_log(LOG_WARNING, "Unable to create autoservice thread :(\n");
				/* There will only be a single member in the list at this point,
				   the one we just added. */
				AST_RWLIST_REMOVE(&aslist, as, list);
				ast_free(as);
				res = -1;
			} else
				pthread_kill(asthread, SIGURG);
		}
	}

	AST_RWLIST_UNLOCK(&aslist);

	return res;
}

int ast_autoservice_stop(struct ast_channel *chan)
{
	int res = -1;
	struct asent *as;
	AST_LIST_HEAD_NOLOCK(, ast_frame) dtmf_frames;
	struct ast_frame *f;
	int removed = 0;

	AST_LIST_HEAD_INIT_NOLOCK(&dtmf_frames);

	AST_RWLIST_WRLOCK(&aslist);
	AST_RWLIST_TRAVERSE_SAFE_BEGIN(&aslist, as, list) {	
		if (as->chan == chan) {
			AST_RWLIST_REMOVE_CURRENT(list);
			as->use_count--;
			if (as->use_count)
				break;
			AST_LIST_APPEND_LIST(&dtmf_frames, &as->dtmf_frames, frame_list);
			ast_free(as);
			removed = 1;
			if (!ast_check_hangup(chan))
				res = 0;
			break;
		}
	}
	AST_RWLIST_TRAVERSE_SAFE_END;

	if (removed && asthread != AST_PTHREADT_NULL) 
		pthread_kill(asthread, SIGURG);
	
	AST_RWLIST_UNLOCK(&aslist);

	if (!removed)
		return 0;

	/* Wait for it to un-block */
	while (ast_test_flag(chan, AST_FLAG_BLOCKING))
		usleep(1000);

	while ((f = AST_LIST_REMOVE_HEAD(&dtmf_frames, frame_list))) {
		ast_queue_frame(chan, f);
		ast_frfree(f);
	}

	return res;
}