chan_alsa.c

Asterisk中信道部分的源码 。。。。

	if (err <= 0)
		ast_log(LOG_ERROR, "Unable to get a poll descriptors count, error is %s\n", snd_strerror(err));
	if (err != 1)
		ast_log(LOG_DEBUG, "Can't handle more than one device\n");

	snd_pcm_poll_descriptors(handle, &pfd, err);
	ast_log(LOG_DEBUG, "Acquired fd %d from the poll descriptor\n", pfd.fd);

	if (stream == SND_PCM_STREAM_CAPTURE)
		readdev = pfd.fd;
	else
		writedev = pfd.fd;

	return handle;
}

static int soundcard_init(void)
{
	alsa.icard = alsa_card_init(indevname, SND_PCM_STREAM_CAPTURE);
	alsa.ocard = alsa_card_init(outdevname, SND_PCM_STREAM_PLAYBACK);

	if (!alsa.icard || !alsa.ocard) {
		ast_log(LOG_ERROR, "Problem opening alsa I/O devices\n");
		return -1;
	}

	return readdev;
}

static int alsa_digit(struct ast_channel *c, char digit, unsigned int duration)
{
	ast_mutex_lock(&alsalock);
	ast_verbose(" << Console Received digit %c of duration %u ms >> \n", 
		digit, duration);
	ast_mutex_unlock(&alsalock);
	return 0;
}

static int alsa_text(struct ast_channel *c, const char *text)
{
	ast_mutex_lock(&alsalock);
	ast_verbose(" << Console Received text %s >> \n", text);
	ast_mutex_unlock(&alsalock);
	return 0;
}

static void grab_owner(void)
{
	while (alsa.owner && ast_mutex_trylock(&alsa.owner->lock)) {
		DEADLOCK_AVOIDANCE(&alsalock);
	}
}

static int alsa_call(struct ast_channel *c, char *dest, int timeout)
{
	int res = 3;
	struct ast_frame f = { AST_FRAME_CONTROL };
	ast_mutex_lock(&alsalock);
	ast_verbose(" << Call placed to '%s' on console >> \n", dest);
	if (autoanswer) {
		ast_verbose(" << Auto-answered >> \n");
		grab_owner();
		if (alsa.owner) {
			f.subclass = AST_CONTROL_ANSWER;
			ast_queue_frame(alsa.owner, &f);
			ast_mutex_unlock(&alsa.owner->lock);
		}
	} else {
		ast_verbose(" << Type 'answer' to answer, or use 'autoanswer' for future calls >> \n");
		grab_owner();
		if (alsa.owner) {
			f.subclass = AST_CONTROL_RINGING;
			ast_queue_frame(alsa.owner, &f);
			ast_mutex_unlock(&alsa.owner->lock);
		}
		write(sndcmd[1], &res, sizeof(res));
	}
	snd_pcm_prepare(alsa.icard);
	snd_pcm_start(alsa.icard);
	ast_mutex_unlock(&alsalock);
	return 0;
}

static void answer_sound(void)
{
	int res;
	nosound = 1;
	res = 4;
	write(sndcmd[1], &res, sizeof(res));

}

static int alsa_answer(struct ast_channel *c)
{
	ast_mutex_lock(&alsalock);
	ast_verbose(" << Console call has been answered >> \n");
	answer_sound();
	ast_setstate(c, AST_STATE_UP);
	cursound = -1;
	snd_pcm_prepare(alsa.icard);
	snd_pcm_start(alsa.icard);
	ast_mutex_unlock(&alsalock);
	return 0;
}

static int alsa_hangup(struct ast_channel *c)
{
	int res;
	ast_mutex_lock(&alsalock);
	cursound = -1;
	c->tech_pvt = NULL;
	alsa.owner = NULL;
	ast_verbose(" << Hangup on console >> \n");
	ast_module_unref(ast_module_info->self);
	if (hookstate) {
		hookstate = 0;
		if (!autoanswer) {
			/* Congestion noise */
			res = 2;
			write(sndcmd[1], &res, sizeof(res));
		}
	}
	snd_pcm_drop(alsa.icard);
	ast_mutex_unlock(&alsalock);
	return 0;
}

static int alsa_write(struct ast_channel *chan, struct ast_frame *f)
{
	static char sizbuf[8000];
	static int sizpos = 0;
	int len = sizpos;
	int pos;
	int res = 0;
	/* size_t frames = 0; */
	snd_pcm_state_t state;

	/* Immediately return if no sound is enabled */
	if (nosound)
		return 0;

	ast_mutex_lock(&alsalock);
	/* Stop any currently playing sound */
	if (cursound != -1) {
		snd_pcm_drop(alsa.ocard);
		snd_pcm_prepare(alsa.ocard);
		cursound = -1;
	}


	/* We have to digest the frame in 160-byte portions */
	if (f->datalen > sizeof(sizbuf) - sizpos) {
		ast_log(LOG_WARNING, "Frame too large\n");
		res = -1;
	} else {
		memcpy(sizbuf + sizpos, f->data, f->datalen);
		len += f->datalen;
		pos = 0;
#ifdef ALSA_MONITOR
		alsa_monitor_write(sizbuf, len);
#endif
		state = snd_pcm_state(alsa.ocard);
		if (state == SND_PCM_STATE_XRUN)
			snd_pcm_prepare(alsa.ocard);
		res = snd_pcm_writei(alsa.ocard, sizbuf, len / 2);
		if (res == -EPIPE) {
#if DEBUG
			ast_log(LOG_DEBUG, "XRUN write\n");
#endif
			snd_pcm_prepare(alsa.ocard);
			res = snd_pcm_writei(alsa.ocard, sizbuf, len / 2);
			if (res != len / 2) {
				ast_log(LOG_ERROR, "Write error: %s\n", snd_strerror(res));
				res = -1;
			} else if (res < 0) {
				ast_log(LOG_ERROR, "Write error %s\n", snd_strerror(res));
				res = -1;
			}
		} else {
			if (res == -ESTRPIPE)
				ast_log(LOG_ERROR, "You've got some big problems\n");
			else if (res < 0)
				ast_log(LOG_NOTICE, "Error %d on write\n", res);
		}
	}
	ast_mutex_unlock(&alsalock);
	if (res > 0)
		res = 0;
	return res;
}


static struct ast_frame *alsa_read(struct ast_channel *chan)
{
	static struct ast_frame f;
	static short __buf[FRAME_SIZE + AST_FRIENDLY_OFFSET / 2];
	short *buf;
	static int readpos = 0;
	static int left = FRAME_SIZE;
	snd_pcm_state_t state;
	int r = 0;
	int off = 0;

	ast_mutex_lock(&alsalock);
	/* Acknowledge any pending cmd */
	f.frametype = AST_FRAME_NULL;
	f.subclass = 0;
	f.samples = 0;
	f.datalen = 0;
	f.data = NULL;
	f.offset = 0;
	f.src = "Console";
	f.mallocd = 0;
	f.delivery.tv_sec = 0;
	f.delivery.tv_usec = 0;

	state = snd_pcm_state(alsa.icard);
	if ((state != SND_PCM_STATE_PREPARED) && (state != SND_PCM_STATE_RUNNING)) {
		snd_pcm_prepare(alsa.icard);
	}

	buf = __buf + AST_FRIENDLY_OFFSET / 2;

	r = snd_pcm_readi(alsa.icard, buf + readpos, left);
	if (r == -EPIPE) {
#if DEBUG
		ast_log(LOG_ERROR, "XRUN read\n");
#endif
		snd_pcm_prepare(alsa.icard);
	} else if (r == -ESTRPIPE) {
		ast_log(LOG_ERROR, "-ESTRPIPE\n");
		snd_pcm_prepare(alsa.icard);
	} else if (r < 0) {
		ast_log(LOG_ERROR, "Read error: %s\n", snd_strerror(r));
	} else if (r >= 0) {
		off -= r;
	}
	/* Update positions */
	readpos += r;
	left -= r;

	if (readpos >= FRAME_SIZE) {
		/* A real frame */
		readpos = 0;
		left = FRAME_SIZE;
		if (chan->_state != AST_STATE_UP) {
			/* Don't transmit unless it's up */
			ast_mutex_unlock(&alsalock);
			return &f;
		}
		f.frametype = AST_FRAME_VOICE;
		f.subclass = AST_FORMAT_SLINEAR;
		f.samples = FRAME_SIZE;
		f.datalen = FRAME_SIZE * 2;
		f.data = buf;
		f.offset = AST_FRIENDLY_OFFSET;
		f.src = "Console";
		f.mallocd = 0;
#ifdef ALSA_MONITOR
		alsa_monitor_read((char *) buf, FRAME_SIZE * 2);
#endif

	}
	ast_mutex_unlock(&alsalock);
	return &f;
}

static int alsa_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
{
	struct chan_alsa_pvt *p = newchan->tech_pvt;
	ast_mutex_lock(&alsalock);
	p->owner = newchan;
	ast_mutex_unlock(&alsalock);
	return 0;
}

static int alsa_indicate(struct ast_channel *chan, int cond, const void *data, size_t datalen)
{
	int res = 0;

	ast_mutex_lock(&alsalock);

	switch (cond) {
	case AST_CONTROL_BUSY:
		res = 1;
		break;
	case AST_CONTROL_CONGESTION:
		res = 2;
		break;
	case AST_CONTROL_RINGING:
	case AST_CONTROL_PROGRESS:
		break;
	case -1:
		res = -1;
		break;
	case AST_CONTROL_VIDUPDATE:
		res = -1;
		break;
	case AST_CONTROL_HOLD:
		ast_verbose(" << Console Has Been Placed on Hold >> \n");
		ast_moh_start(chan, data, mohinterpret);
		break;
	case AST_CONTROL_UNHOLD:
		ast_verbose(" << Console Has Been Retrieved from Hold >> \n");
		ast_moh_stop(chan);
		break;
	case AST_CONTROL_SRCUPDATE:
		break;
	default:
		ast_log(LOG_WARNING, "Don't know how to display condition %d on %s\n", cond, chan->name);
		res = -1;
	}

	if (res > -1)
		write(sndcmd[1], &res, sizeof(res));

	ast_mutex_unlock(&alsalock);

	return res;
}

static struct ast_channel *alsa_new(struct chan_alsa_pvt *p, int state)
{
	struct ast_channel *tmp = NULL;
	
	if (!(tmp = ast_channel_alloc(1, state, 0, 0, "", p->exten, p->context, 0, "ALSA/%s", indevname)))
		return NULL;

	tmp->tech = &alsa_tech;
	tmp->fds[0] = readdev;
	tmp->nativeformats = AST_FORMAT_SLINEAR;
	tmp->readformat = AST_FORMAT_SLINEAR;
	tmp->writeformat = AST_FORMAT_SLINEAR;
	tmp->tech_pvt = p;
	if (!ast_strlen_zero(p->context))
		ast_copy_string(tmp->context, p->context, sizeof(tmp->context));
	if (!ast_strlen_zero(p->exten))
		ast_copy_string(tmp->exten, p->exten, sizeof(tmp->exten));
	if (!ast_strlen_zero(language))
		ast_string_field_set(tmp, language, language);
	p->owner = tmp;
	ast_module_ref(ast_module_info->self);
	ast_jb_configure(tmp, &global_jbconf);
	if (state != AST_STATE_DOWN) {
		if (ast_pbx_start(tmp)) {
			ast_log(LOG_WARNING, "Unable to start PBX on %s\n", tmp->name);
			ast_hangup(tmp);
			tmp = NULL;
		}
	}

	return tmp;
}

static struct ast_channel *alsa_request(const char *type, int format, void *data, int *cause)
{
	int oldformat = format;
	struct ast_channel *tmp = NULL;

	format &= AST_FORMAT_SLINEAR;
	if (!format) {
		ast_log(LOG_NOTICE, "Asked to get a channel of format '%d'\n", oldformat);
		return NULL;
	}

	ast_mutex_lock(&alsalock);

	if (alsa.owner) {
		ast_log(LOG_NOTICE, "Already have a call on the ALSA channel\n");
		*cause = AST_CAUSE_BUSY;
	} else if (!(tmp = alsa_new(&alsa, AST_STATE_DOWN)))
		ast_log(LOG_WARNING, "Unable to create new ALSA channel\n");

	ast_mutex_unlock(&alsalock);

	return tmp;
}

static int console_autoanswer_deprecated(int fd, int argc, char *argv[])
{
	int res = RESULT_SUCCESS;

	if ((argc != 1) && (argc != 2))
		return RESULT_SHOWUSAGE;

	ast_mutex_lock(&alsalock);

	if (argc == 1) {
		ast_cli(fd, "Auto answer is %s.\n", autoanswer ? "on" : "off");
	} else {
		if (!strcasecmp(argv[1], "on"))
			autoanswer = -1;
		else if (!strcasecmp(argv[1], "off"))
			autoanswer = 0;
		else
			res = RESULT_SHOWUSAGE;
	}

	ast_mutex_unlock(&alsalock);

	return res;
}

static int console_autoanswer(int fd, int argc, char *argv[])
{
	int res = RESULT_SUCCESS;;
	if ((argc != 2) && (argc != 3))
		return RESULT_SHOWUSAGE;
	ast_mutex_lock(&alsalock);
	if (argc == 2) {
		ast_cli(fd, "Auto answer is %s.\n", autoanswer ? "on" : "off");
	} else {
		if (!strcasecmp(argv[2], "on"))
			autoanswer = -1;
		else if (!strcasecmp(argv[2], "off"))
			autoanswer = 0;
		else
			res = RESULT_SHOWUSAGE;
	}
	ast_mutex_unlock(&alsalock);
	return res;
}

static char *autoanswer_complete(const char *line, const char *word, int pos, int state)
{
#ifndef MIN
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
	switch (state) {
		case 0:
			if (!ast_strlen_zero(word) && !strncasecmp(word, "on", MIN(strlen(word), 2)))
				return ast_strdup("on");
		case 1:
			if (!ast_strlen_zero(word) && !strncasecmp(word, "off", MIN(strlen(word), 3)))
				return ast_strdup("off");
		default:
			return NULL;
	}
	return NULL;
}

static const char autoanswer_usage[] =
	"Usage: console autoanswer [on|off]\n"
	"       Enables or disables autoanswer feature.  If used without\n"
	"       argument, displays the current on/off status of autoanswer.\n"
	"       The default value of autoanswer is in 'alsa.conf'.\n";

static int console_answer_deprecated(int fd, int argc, char *argv[])
{
	int res = RESULT_SUCCESS;

	if (argc != 1)
		return RESULT_SHOWUSAGE;

	ast_mutex_lock(&alsalock);

	if (!alsa.owner) {
		ast_cli(fd, "No one is calling us\n");
		res = RESULT_FAILURE;