seq_clientmgr.c

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		if (snd_seq_ev_is_variable(&event)) {
			int extlen = event.data.ext.len & ~SNDRV_SEQ_EXT_MASK;
			if ((size_t)(extlen + len) > count) {
				/* back out, will get an error this time or next */
				err = -EINVAL;
				break;
			}
			/* set user space pointer */
			event.data.ext.len = extlen | SNDRV_SEQ_EXT_USRPTR;
			event.data.ext.ptr = (char*)buf + sizeof(snd_seq_event_t);
			len += extlen; /* increment data length */
		} else {
#if defined(CONFIG_SND_BIT32_EMUL) || defined(CONFIG_SND_BIT32_EMUL_MODULE)
			if (client->convert32 && snd_seq_ev_is_varusr(&event)) {
				void *ptr = compat_ptr(event.data.raw32.d[1]);
				event.data.ext.ptr = ptr;
			}
#endif
		}

		/* ok, enqueue it */
		err = snd_seq_client_enqueue_event(client, &event, file,
						   !(file->f_flags & O_NONBLOCK),
						   0, 0);
		if (err < 0)
			break;

	__skip_event:
		/* Update pointers and counts */
		count -= len;
		buf += len;
		written += len;
	}

	return written ? written : err;
}


/*
 * handle polling
 */
static unsigned int snd_seq_poll(struct file *file, poll_table * wait)
{
	client_t *client = (client_t *) file->private_data;
	unsigned int mask = 0;

	/* check client structures are in place */
	snd_assert(client != NULL, return -ENXIO);

	if ((snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_INPUT) &&
	    client->data.user.fifo) {

		/* check if data is available in the outqueue */
		if (snd_seq_fifo_poll_wait(client->data.user.fifo, file, wait))
			mask |= POLLIN | POLLRDNORM;
	}

	if (snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_OUTPUT) {

		/* check if data is available in the pool */
		if (!snd_seq_write_pool_allocated(client) ||
		    snd_seq_pool_poll_wait(client->pool, file, wait))
			mask |= POLLOUT | POLLWRNORM;
	}

	return mask;
}


/*-----------------------------------------------------*/


/* SYSTEM_INFO ioctl() */
static int snd_seq_ioctl_system_info(client_t *client, void __user *arg)
{
	snd_seq_system_info_t info;

	memset(&info, 0, sizeof(info));
	/* fill the info fields */
	info.queues = SNDRV_SEQ_MAX_QUEUES;
	info.clients = SNDRV_SEQ_MAX_CLIENTS;
	info.ports = 256;	/* fixed limit */
	info.channels = 256;	/* fixed limit */
	info.cur_clients = client_usage.cur;
	info.cur_queues = snd_seq_queue_get_cur_queues();

	if (copy_to_user(arg, &info, sizeof(info)))
		return -EFAULT;
	return 0;
}


/* RUNNING_MODE ioctl() */
static int snd_seq_ioctl_running_mode(client_t *client, void __user *arg)
{
	struct sndrv_seq_running_info info;
	client_t *cptr;
	int err = 0;

	if (copy_from_user(&info, arg, sizeof(info)))
		return -EFAULT;

	/* requested client number */
	cptr = snd_seq_client_use_ptr(info.client);
	if (cptr == NULL)
		return -ENOENT;		/* don't change !!! */

#ifdef SNDRV_BIG_ENDIAN
	if (! info.big_endian) {
		err = -EINVAL;
		goto __err;
	}
#else
	if (info.big_endian) {
		err = -EINVAL;
		goto __err;
	}

#endif
	if (info.cpu_mode > sizeof(long)) {
		err = -EINVAL;
		goto __err;
	}
	cptr->convert32 = (info.cpu_mode < sizeof(long));
 __err:
	snd_seq_client_unlock(cptr);
	return err;
}

/* CLIENT_INFO ioctl() */
static void get_client_info(client_t *cptr, snd_seq_client_info_t *info)
{
	info->client = cptr->number;

	/* fill the info fields */
	info->type = cptr->type;
	strcpy(info->name, cptr->name);
	info->filter = cptr->filter;
	info->event_lost = cptr->event_lost;
	memcpy(info->event_filter, cptr->event_filter, 32);
	info->num_ports = cptr->num_ports;
	memset(info->reserved, 0, sizeof(info->reserved));
}

static int snd_seq_ioctl_get_client_info(client_t * client, void __user *arg)
{
	client_t *cptr;
	snd_seq_client_info_t client_info;

	if (copy_from_user(&client_info, arg, sizeof(client_info)))
		return -EFAULT;

	/* requested client number */
	cptr = snd_seq_client_use_ptr(client_info.client);
	if (cptr == NULL)
		return -ENOENT;		/* don't change !!! */

	get_client_info(cptr, &client_info);
	snd_seq_client_unlock(cptr);

	if (copy_to_user(arg, &client_info, sizeof(client_info)))
		return -EFAULT;
	return 0;
}


/* CLIENT_INFO ioctl() */
static int snd_seq_ioctl_set_client_info(client_t * client, void __user *arg)
{
	snd_seq_client_info_t client_info;

	if (copy_from_user(&client_info, arg, sizeof(client_info)))
		return -EFAULT;

	/* it is not allowed to set the info fields for an another client */
	if (client->number != client_info.client)
		return -EPERM;
	/* also client type must be set now */
	if (client->type != client_info.type)
		return -EINVAL;

	/* fill the info fields */
	if (client_info.name[0])
		strlcpy(client->name, client_info.name, sizeof(client->name));

	client->filter = client_info.filter;
	client->event_lost = client_info.event_lost;
	memcpy(client->event_filter, client_info.event_filter, 32);

	return 0;
}


/* 
 * CREATE PORT ioctl() 
 */
static int snd_seq_ioctl_create_port(client_t * client, void __user *arg)
{
	client_port_t *port;
	snd_seq_port_info_t info;
	snd_seq_port_callback_t *callback;

	if (copy_from_user(&info, arg, sizeof(info)))
		return -EFAULT;

	/* it is not allowed to create the port for an another client */
	if (info.addr.client != client->number)
		return -EPERM;

	port = snd_seq_create_port(client, (info.flags & SNDRV_SEQ_PORT_FLG_GIVEN_PORT) ? info.addr.port : -1);
	if (port == NULL)
		return -ENOMEM;

	if (client->type == USER_CLIENT && info.kernel) {
		snd_seq_delete_port(client, port->addr.port);
		return -EINVAL;
	}
	if (client->type == KERNEL_CLIENT) {
		if ((callback = info.kernel) != NULL) {
			if (callback->owner)
				port->owner = callback->owner;
			port->private_data = callback->private_data;
			port->private_free = callback->private_free;
			port->callback_all = callback->callback_all;
			port->event_input = callback->event_input;
			port->c_src.open = callback->subscribe;
			port->c_src.close = callback->unsubscribe;
			port->c_dest.open = callback->use;
			port->c_dest.close = callback->unuse;
		}
	}

	info.addr = port->addr;

	snd_seq_set_port_info(port, &info);
	snd_seq_system_client_ev_port_start(port->addr.client, port->addr.port);

	if (copy_to_user(arg, &info, sizeof(info)))
		return -EFAULT;

	return 0;
}

/* 
 * DELETE PORT ioctl() 
 */
static int snd_seq_ioctl_delete_port(client_t * client, void __user *arg)
{
	snd_seq_port_info_t info;
	int err;

	/* set passed parameters */
	if (copy_from_user(&info, arg, sizeof(info)))
		return -EFAULT;
	
	/* it is not allowed to remove the port for an another client */
	if (info.addr.client != client->number)
		return -EPERM;

	err = snd_seq_delete_port(client, info.addr.port);
	if (err >= 0)
		snd_seq_system_client_ev_port_exit(client->number, info.addr.port);
	return err;
}


/* 
 * GET_PORT_INFO ioctl() (on any client) 
 */
static int snd_seq_ioctl_get_port_info(client_t *client, void __user *arg)
{
	client_t *cptr;
	client_port_t *port;
	snd_seq_port_info_t info;

	if (copy_from_user(&info, arg, sizeof(info)))
		return -EFAULT;
	cptr = snd_seq_client_use_ptr(info.addr.client);
	if (cptr == NULL)
		return -ENXIO;

	port = snd_seq_port_use_ptr(cptr, info.addr.port);
	if (port == NULL) {
		snd_seq_client_unlock(cptr);
		return -ENOENT;			/* don't change */
	}

	/* get port info */
	snd_seq_get_port_info(port, &info);
	snd_seq_port_unlock(port);
	snd_seq_client_unlock(cptr);

	if (copy_to_user(arg, &info, sizeof(info)))
		return -EFAULT;
	return 0;
}


/* 
 * SET_PORT_INFO ioctl() (only ports on this/own client) 
 */
static int snd_seq_ioctl_set_port_info(client_t * client, void __user *arg)
{
	client_port_t *port;
	snd_seq_port_info_t info;

	if (copy_from_user(&info, arg, sizeof(info)))
		return -EFAULT;

	if (info.addr.client != client->number) /* only set our own ports ! */
		return -EPERM;
	port = snd_seq_port_use_ptr(client, info.addr.port);
	if (port) {
		snd_seq_set_port_info(port, &info);
		snd_seq_port_unlock(port);
	}
	return 0;
}


/*
 * port subscription (connection)
 */
#define PERM_RD		(SNDRV_SEQ_PORT_CAP_READ|SNDRV_SEQ_PORT_CAP_SUBS_READ)
#define PERM_WR		(SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_SUBS_WRITE)

static int check_subscription_permission(client_t *client, client_port_t *sport,
					 client_port_t *dport,
					 snd_seq_port_subscribe_t *subs)
{
	if (client->number != subs->sender.client &&
	    client->number != subs->dest.client) {
		/* connection by third client - check export permission */
		if (check_port_perm(sport, SNDRV_SEQ_PORT_CAP_NO_EXPORT))
			return -EPERM;
		if (check_port_perm(dport, SNDRV_SEQ_PORT_CAP_NO_EXPORT))
			return -EPERM;
	}

	/* check read permission */
	/* if sender or receiver is the subscribing client itself,
	 * no permission check is necessary
	 */
	if (client->number != subs->sender.client) {
		if (! check_port_perm(sport, PERM_RD))
			return -EPERM;
	}
	/* check write permission */
	if (client->number != subs->dest.client) {
		if (! check_port_perm(dport, PERM_WR))
			return -EPERM;
	}
	return 0;
}

/*
 * send an subscription notify event to user client:
 * client must be user client.
 */
int snd_seq_client_notify_subscription(int client, int port,
				       snd_seq_port_subscribe_t *info, int evtype)
{
	snd_seq_event_t event;

	memset(&event, 0, sizeof(event));
	event.type = evtype;
	event.data.connect.dest = info->dest;
	event.data.connect.sender = info->sender;

	return snd_seq_system_notify(client, port, &event);  /* non-atomic */
}


/* 
 * add to port's subscription list IOCTL interface 
 */
static int snd_seq_ioctl_subscribe_port(client_t * client, void __user *arg)
{
	int result = -EINVAL;
	client_t *receiver = NULL, *sender = NULL;
	client_port_t *sport = NULL, *dport = NULL;
	snd_seq_port_subscribe_t subs;

	if (copy_from_user(&subs, arg, sizeof(subs)))
		return -EFAULT;

	if ((receiver = snd_seq_client_use_ptr(subs.dest.client)) == NULL)
		goto __end;
	if ((sender = snd_seq_client_use_ptr(subs.sender.client)) == NULL)
		goto __end;
	if ((sport = snd_seq_port_use_ptr(sender, subs.sender.port)) == NULL)
		goto __end;
	if ((dport = snd_seq_port_use_ptr(receiver, subs.dest.port)) == NULL)
		goto __end;

	result = check_subscription_permission(client, sport, dport, &subs);
	if (result < 0)
		goto __end;

	/* connect them */
	result = snd_seq_port_connect(client, sender, sport, receiver, dport, &subs);
	if (! result) /* broadcast announce */
		snd_seq_client_notify_subscription(SNDRV_SEQ_ADDRESS_SUBSCRIBERS, 0,
						   &subs, SNDRV_SEQ_EVENT_PORT_SUBSCRIBED);
      __end:
      	if (sport)
		snd_seq_port_unlock(sport);
	if (dport)
		snd_seq_port_unlock(dport);
	if (sender)
		snd_seq_client_unlock(sender);
	if (receiver)
		snd_seq_client_unlock(receiver);
	return result;
}


/* 
 * remove from port's subscription list 
 */
static int snd_seq_ioctl_unsubscribe_port(client_t * client, void __user *arg)
{
	int result = -ENXIO;
	client_t *receiver = NULL, *sender = NULL;
	client_port_t *sport = NULL, *dport = NULL;
	snd_seq_port_subscribe_t subs;

	if (copy_from_user(&subs, arg, sizeof(subs)))
		return -EFAULT;

	if ((receiver = snd_seq_client_use_ptr(subs.dest.client)) == NULL)
		goto __end;
	if ((sender = snd_seq_client_use_ptr(subs.sender.client)) == NULL)
		goto __end;
	if ((sport = snd_seq_port_use_ptr(sender, subs.sender.port)) == NULL)
		goto __end;
	if ((dport = snd_seq_port_use_ptr(receiver, subs.dest.port)) == NULL)
		goto __end;

	result = check_subscription_permission(client, sport, dport, &subs);
	if (result < 0)
		goto __end;

	result = snd_seq_port_disconnect(client, sender, sport, receiver, dport, &subs);
	if (! result) /* broadcast announce */
		snd_seq_client_notify_subscription(SNDRV_SEQ_ADDRESS_SUBSCRIBERS, 0,
						   &subs, SNDRV_SEQ_EVENT_PORT_UNSUBSCRIBED);
      __end:
      	if (sport)
		snd_seq_port_unlock(sport);
	if (dport)
		snd_seq_port_unlock(dport);
	if (sender)
		snd_seq_client_unlock(sender);
	if (receiver)
		snd_seq_client_unlock(receiver);
	return result;
}


/* CREATE_QUEUE ioctl() */
static int snd_seq_ioctl_create_queue(client_t *client, void __user *arg)
{
	snd_seq_queue_info_t info;
	int result;
	queue_t *q;

	if (copy_from_user(&info, arg, sizeof(info)))
		return -EFAULT;

	result = snd_seq_queue_alloc(client->number, info.locked, info.flags);
	if (result < 0)
		return result;

	q = queueptr(result);
	if (q == NULL)
		return -EINVAL;

	info.queue = q->queue;
	info.locked = q->locked;
	info.owner = q->owner;

	/* set queue name */
	if (! info.name[0])
		snprintf(info.name, sizeof(info.name), "Queue-%d", q->queue);
	strlcpy(q->name, info.name, sizeof(q->name));
	queuefree(q);

	if (copy_to_user(arg, &info, sizeof(info)))
		return -EFAULT;

	return 0;
}

/* DELETE_QUEUE ioctl() */
static int snd_seq_ioctl_delete_queue(client_t *client, void __user *arg)
{
	snd_seq_queue_info_t info;

	if (copy_from_user(&info, arg, sizeof(info)))
		return -EFAULT;