seq_clientmgr.c

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	    ! client->accept_input)
		return 0; /* ignored */

	/* set up quoted error */
	memset(&bounce_ev, 0, sizeof(bounce_ev));
	bounce_ev.type = SNDRV_SEQ_EVENT_KERNEL_ERROR;
	bounce_ev.flags = SNDRV_SEQ_EVENT_LENGTH_FIXED;
	bounce_ev.queue = SNDRV_SEQ_QUEUE_DIRECT;
	bounce_ev.source.client = SNDRV_SEQ_CLIENT_SYSTEM;
	bounce_ev.source.port = SNDRV_SEQ_PORT_SYSTEM_ANNOUNCE;
	bounce_ev.dest.client = client->number;
	bounce_ev.dest.port = event->source.port;
	bounce_ev.data.quote.origin = event->dest;
	bounce_ev.data.quote.event = event;
	bounce_ev.data.quote.value = -err; /* use positive value */
	result = snd_seq_deliver_single_event(NULL, &bounce_ev, 0, atomic, hop + 1);
	if (result < 0) {
		client->event_lost++;
		return result;
	}

	return result;
}


/*
 * rewrite the time-stamp of the event record with the curren time
 * of the given queue.
 * return non-zero if updated.
 */
static int update_timestamp_of_queue(snd_seq_event_t *event, int queue, int real_time)
{
	queue_t *q;

	q = queueptr(queue);
	if (! q)
		return 0;
	event->queue = queue;
	event->flags &= ~SNDRV_SEQ_TIME_STAMP_MASK;
	if (real_time) {
		event->time.time = snd_seq_timer_get_cur_time(q->timer);
		event->flags |= SNDRV_SEQ_TIME_STAMP_REAL;
	} else {
		event->time.tick = snd_seq_timer_get_cur_tick(q->timer);
		event->flags |= SNDRV_SEQ_TIME_STAMP_TICK;
	}
	queuefree(q);
	return 1;
}


/*
 * deliver an event to the specified destination.
 * if filter is non-zero, client filter bitmap is tested.
 *
 *  RETURN VALUE: 0 : if succeeded
 *		 <0 : error
 */
static int snd_seq_deliver_single_event(client_t *client,
					snd_seq_event_t *event,
					int filter, int atomic, int hop)
{
	client_t *dest = NULL;
	client_port_t *dest_port = NULL;
	int result = -ENOENT;
	int direct;

	direct = snd_seq_ev_is_direct(event);

	dest = get_event_dest_client(event, filter);
	if (dest == NULL)
		goto __skip;
	dest_port = snd_seq_port_use_ptr(dest, event->dest.port);
	if (dest_port == NULL)
		goto __skip;

	/* check permission */
	if (! check_port_perm(dest_port, SNDRV_SEQ_PORT_CAP_WRITE)) {
		result = -EPERM;
		goto __skip;
	}
		
	if (dest_port->timestamping)
		update_timestamp_of_queue(event, dest_port->time_queue,
					  dest_port->time_real);

	switch (dest->type) {
	case USER_CLIENT:
		if (dest->data.user.fifo)
			result = snd_seq_fifo_event_in(dest->data.user.fifo, event);
		break;

	case KERNEL_CLIENT:
		if (dest_port->event_input == NULL)
			break;
		result = dest_port->event_input(event, direct, dest_port->private_data, atomic, hop);
		break;
	default:
		break;
	}

  __skip:
	if (dest_port)
		snd_seq_port_unlock(dest_port);
	if (dest)
		snd_seq_client_unlock(dest);

	if (result < 0 && !direct) {
		result = bounce_error_event(client, event, result, atomic, hop);
	}
	return result;
}


/*
 * send the event to all subscribers:
 */
static int deliver_to_subscribers(client_t *client,
				  snd_seq_event_t *event,
				  int atomic, int hop)
{
	subscribers_t *subs;
	int err = 0, num_ev = 0;
	snd_seq_event_t event_saved;
	client_port_t *src_port;
	struct list_head *p;
	port_subs_info_t *grp;

	src_port = snd_seq_port_use_ptr(client, event->source.port);
	if (src_port == NULL)
		return -EINVAL; /* invalid source port */
	/* save original event record */
	event_saved = *event;
	grp = &src_port->c_src;
	
	/* lock list */
	if (atomic)
		read_lock(&grp->list_lock);
	else
		down_read(&grp->list_mutex);
	list_for_each(p, &grp->list_head) {
		subs = list_entry(p, subscribers_t, src_list);
		event->dest = subs->info.dest;
		if (subs->info.flags & SNDRV_SEQ_PORT_SUBS_TIMESTAMP)
			/* convert time according to flag with subscription */
			update_timestamp_of_queue(event, subs->info.queue,
						  subs->info.flags & SNDRV_SEQ_PORT_SUBS_TIME_REAL);
		err = snd_seq_deliver_single_event(client, event,
						   0, atomic, hop);
		if (err < 0)
			break;
		num_ev++;
		/* restore original event record */
		*event = event_saved;
	}
	if (atomic)
		read_unlock(&grp->list_lock);
	else
		up_read(&grp->list_mutex);
	*event = event_saved; /* restore */
	snd_seq_port_unlock(src_port);
	return (err < 0) ? err : num_ev;
}


#ifdef SUPPORT_BROADCAST 
/*
 * broadcast to all ports:
 */
static int port_broadcast_event(client_t *client,
				snd_seq_event_t *event,
				int atomic, int hop)
{
	int num_ev = 0, err = 0;
	client_t *dest_client;
	struct list_head *p;

	dest_client = get_event_dest_client(event, SNDRV_SEQ_FILTER_BROADCAST);
	if (dest_client == NULL)
		return 0; /* no matching destination */

	read_lock(&dest_client->ports_lock);
	list_for_each(p, &dest_client->ports_list_head) {
		client_port_t *port = list_entry(p, client_port_t, list);
		event->dest.port = port->addr.port;
		/* pass NULL as source client to avoid error bounce */
		err = snd_seq_deliver_single_event(NULL, event,
						   SNDRV_SEQ_FILTER_BROADCAST,
						   atomic, hop);
		if (err < 0)
			break;
		num_ev++;
	}
	read_unlock(&dest_client->ports_lock);
	snd_seq_client_unlock(dest_client);
	event->dest.port = SNDRV_SEQ_ADDRESS_BROADCAST; /* restore */
	return (err < 0) ? err : num_ev;
}

/*
 * send the event to all clients:
 * if destination port is also ADDRESS_BROADCAST, deliver to all ports.
 */
static int broadcast_event(client_t *client,
			   snd_seq_event_t *event, int atomic, int hop)
{
	int err = 0, num_ev = 0;
	int dest;
	snd_seq_addr_t addr;

	addr = event->dest; /* save */

	for (dest = 0; dest < SNDRV_SEQ_MAX_CLIENTS; dest++) {
		/* don't send to itself */
		if (dest == client->number)
			continue;
		event->dest.client = dest;
		event->dest.port = addr.port;
		if (addr.port == SNDRV_SEQ_ADDRESS_BROADCAST)
			err = port_broadcast_event(client, event, atomic, hop);
		else
			/* pass NULL as source client to avoid error bounce */
			err = snd_seq_deliver_single_event(NULL, event,
							   SNDRV_SEQ_FILTER_BROADCAST,
							   atomic, hop);
		if (err < 0)
			break;
		num_ev += err;
	}
	event->dest = addr; /* restore */
	return (err < 0) ? err : num_ev;
}


/* multicast - not supported yet */
static int multicast_event(client_t *client, snd_seq_event_t *event,
			   int atomic, int hop)
{
	snd_printd("seq: multicast not supported yet.\n");
	return 0; /* ignored */
}
#endif /* SUPPORT_BROADCAST */


/* deliver an event to the destination port(s).
 * if the event is to subscribers or broadcast, the event is dispatched
 * to multiple targets.
 *
 * RETURN VALUE: n > 0  : the number of delivered events.
 *               n == 0 : the event was not passed to any client.
 *               n < 0  : error - event was not processed.
 */
static int snd_seq_deliver_event(client_t *client, snd_seq_event_t *event,
				 int atomic, int hop)
{
	int result;

	hop++;
	if (hop >= SNDRV_SEQ_MAX_HOPS) {
		snd_printd("too long delivery path (%d:%d->%d:%d)\n",
			   event->source.client, event->source.port,
			   event->dest.client, event->dest.port);
		return -EMLINK;
	}

	if (event->queue == SNDRV_SEQ_ADDRESS_SUBSCRIBERS ||
	    event->dest.client == SNDRV_SEQ_ADDRESS_SUBSCRIBERS)
		result = deliver_to_subscribers(client, event, atomic, hop);
#ifdef SUPPORT_BROADCAST
	else if (event->queue == SNDRV_SEQ_ADDRESS_BROADCAST ||
		 event->dest.client == SNDRV_SEQ_ADDRESS_BROADCAST)
		result = broadcast_event(client, event, atomic, hop);
	else if (event->dest.client >= SNDRV_SEQ_MAX_CLIENTS)
		result = multicast_event(client, event, atomic, hop);
	else if (event->dest.port == SNDRV_SEQ_ADDRESS_BROADCAST)
		result = port_broadcast_event(client, event, atomic, hop);
#endif
	else
		result = snd_seq_deliver_single_event(client, event, 0, atomic, hop);

	return result;
}

/*
 * dispatch an event cell:
 * This function is called only from queue check routines in timer
 * interrupts or after enqueued.
 * The event cell shall be released or re-queued in this function.
 *
 * RETURN VALUE: n > 0  : the number of delivered events.
 *		 n == 0 : the event was not passed to any client.
 *		 n < 0  : error - event was not processed.
 */
int snd_seq_dispatch_event(snd_seq_event_cell_t *cell, int atomic, int hop)
{
	client_t *client;
	int result;

	snd_assert(cell != NULL, return -EINVAL);

	client = snd_seq_client_use_ptr(cell->event.source.client);
	if (client == NULL) {
		snd_seq_cell_free(cell); /* release this cell */
		return -EINVAL;
	}

	if (cell->event.type == SNDRV_SEQ_EVENT_NOTE) {
		/* NOTE event:
		 * the event cell is re-used as a NOTE-OFF event and
		 * enqueued again.
		 */
		snd_seq_event_t tmpev, *ev;

		/* reserve this event to enqueue note-off later */
		tmpev = cell->event;
		tmpev.type = SNDRV_SEQ_EVENT_NOTEON;
		result = snd_seq_deliver_event(client, &tmpev, atomic, hop);

		/*
		 * This was originally a note event.  We now re-use the
		 * cell for the note-off event.
		 */

		ev = &cell->event;
		ev->type = SNDRV_SEQ_EVENT_NOTEOFF;
		ev->flags |= SNDRV_SEQ_PRIORITY_HIGH;

		/* add the duration time */
		switch (ev->flags & SNDRV_SEQ_TIME_STAMP_MASK) {
		case SNDRV_SEQ_TIME_STAMP_TICK:
			ev->time.tick += ev->data.note.duration;
			break;
		case SNDRV_SEQ_TIME_STAMP_REAL:
			/* unit for duration is ms */
			ev->time.time.tv_nsec += 1000000 * (ev->data.note.duration % 1000);
			ev->time.time.tv_sec += ev->data.note.duration / 1000 +
						ev->time.time.tv_nsec / 1000000000;
			ev->time.time.tv_nsec %= 1000000000;
			break;
		}
		ev->data.note.velocity = ev->data.note.off_velocity;

		/* Now queue this cell as the note off event */
		if (snd_seq_enqueue_event(cell, atomic, hop) < 0)
			snd_seq_cell_free(cell); /* release this cell */

	} else {
		/* Normal events:
		 * event cell is freed after processing the event
		 */

		result = snd_seq_deliver_event(client, &cell->event, atomic, hop);
		snd_seq_cell_free(cell);
	}

	snd_seq_client_unlock(client);
	return result;
}


/* Allocate a cell from client pool and enqueue it to queue:
 * if pool is empty and blocking is TRUE, sleep until a new cell is
 * available.
 */
static int snd_seq_client_enqueue_event(client_t *client,
					snd_seq_event_t *event,
					struct file *file, int blocking,
					int atomic, int hop)
{
	snd_seq_event_cell_t *cell;
	int err;

	/* special queue values - force direct passing */
	if (event->queue == SNDRV_SEQ_ADDRESS_SUBSCRIBERS) {
		event->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
		event->queue = SNDRV_SEQ_QUEUE_DIRECT;
	} else
#ifdef SUPPORT_BROADCAST
		if (event->queue == SNDRV_SEQ_ADDRESS_BROADCAST) {
			event->dest.client = SNDRV_SEQ_ADDRESS_BROADCAST;
			event->queue = SNDRV_SEQ_QUEUE_DIRECT;
		}
#endif
	if (event->dest.client == SNDRV_SEQ_ADDRESS_SUBSCRIBERS) {
		/* check presence of source port */
		client_port_t *src_port = snd_seq_port_use_ptr(client, event->source.port);
		if (src_port == NULL)
			return -EINVAL;
		snd_seq_port_unlock(src_port);
	}

	/* direct event processing without enqueued */
	if (snd_seq_ev_is_direct(event)) {
		if (event->type == SNDRV_SEQ_EVENT_NOTE)
			return -EINVAL; /* this event must be enqueued! */
		return snd_seq_deliver_event(client, event, atomic, hop);
	}

	/* Not direct, normal queuing */
	if (snd_seq_queue_is_used(event->queue, client->number) <= 0)
		return -EINVAL;  /* invalid queue */
	if (! snd_seq_write_pool_allocated(client))
		return -ENXIO; /* queue is not allocated */

	/* allocate an event cell */
	err = snd_seq_event_dup(client->pool, event, &cell, !blocking || atomic, file);
	if (err < 0)
		return err;

	/* we got a cell. enqueue it. */
	if ((err = snd_seq_enqueue_event(cell, atomic, hop)) < 0) {
		snd_seq_cell_free(cell);
		return err;
	}

	return 0;
}


/*
 * check validity of event type and data length.
 * return non-zero if invalid.
 */
static int check_event_type_and_length(snd_seq_event_t *ev)
{
	switch (snd_seq_ev_length_type(ev)) {
	case SNDRV_SEQ_EVENT_LENGTH_FIXED:
		if (snd_seq_ev_is_variable_type(ev))
			return -EINVAL;
		break;
	case SNDRV_SEQ_EVENT_LENGTH_VARIABLE:
		if (! snd_seq_ev_is_variable_type(ev) ||
		    (ev->data.ext.len & ~SNDRV_SEQ_EXT_MASK) >= SNDRV_SEQ_MAX_EVENT_LEN)
			return -EINVAL;
		break;
	case SNDRV_SEQ_EVENT_LENGTH_VARUSR:
		if (! snd_seq_ev_is_instr_type(ev) ||
		    ! snd_seq_ev_is_direct(ev))
			return -EINVAL;
		break;
	}
	return 0;
}


/* handle write() */
/* possible error values:
 *	-ENXIO	invalid client or file open mode
 *	-ENOMEM	malloc failed
 *	-EFAULT	seg. fault during copy from user space
 *	-EINVAL	invalid event
 *	-EAGAIN	no space in output pool
 *	-EINTR	interrupts while sleep
 *	-EMLINK	too many hops
 *	others	depends on return value from driver callback
 */
static ssize_t snd_seq_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
{
	client_t *client = (client_t *) file->private_data;
	int written = 0, len;
	int err = -EINVAL;
	snd_seq_event_t event;

	if (!(snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_OUTPUT))
		return -ENXIO;

	/* check client structures are in place */
	snd_assert(client != NULL, return -ENXIO);
		
	if (!client->accept_output || client->pool == NULL)
		return -ENXIO;

	/* allocate the pool now if the pool is not allocated yet */ 
	if (client->pool->size > 0 && !snd_seq_write_pool_allocated(client)) {
		if (snd_seq_pool_init(client->pool) < 0)
			return -ENOMEM;
	}

	/* only process whole events */
	while (count >= sizeof(snd_seq_event_t)) {
		/* Read in the event header from the user */
		len = sizeof(event);
		if (copy_from_user(&event, buf, len)) {
			err = -EFAULT;
			break;
		}
		event.source.client = client->number;	/* fill in client number */
		/* Check for extension data length */
		if (check_event_type_and_length(&event)) {
			err = -EINVAL;
			break;
		}

		/* check for special events */
		if (event.type == SNDRV_SEQ_EVENT_NONE)
			goto __skip_event;
		else if (snd_seq_ev_is_reserved(&event)) {
			err = -EINVAL;
			break;
		}