// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ALSA sequencer Ports
* Copyright (c) 1998 by Frank van de Pol <[email protected]>
* Jaroslav Kysela <[email protected]>
*/
#include <sound/core.h>
#include <linux/slab.h>
#include <linux/module.h>
#include "seq_system.h"
#include "seq_ports.h"
#include "seq_clientmgr.h"
/*
registration of client ports
*/
/*
NOTE: the current implementation of the port structure as a linked list is
not optimal for clients that have many ports. For sending messages to all
subscribers of a port we first need to find the address of the port
structure, which means we have to traverse the list. A direct access table
(array) would be better, but big preallocated arrays waste memory.
Possible actions:
1) leave it this way, a client does normaly does not have more than a few
ports
2) replace the linked list of ports by a array of pointers which is
dynamicly kmalloced. When a port is added or deleted we can simply allocate
a new array, copy the corresponding pointers, and delete the old one. We
then only need a pointer to this array, and an integer that tells us how
much elements are in array.
*/
/* return pointer to port structure - port is locked if found */
struct snd_seq_client_port *snd_seq_port_use_ptr(struct snd_seq_client *client,
int num)
{
struct snd_seq_client_port *port;
if (client == NULL)
return NULL;
guard(read_lock)(&client->ports_lock);
list_for_each_entry(port, &client->ports_list_head, list) {
if (port->addr.port == num) {
if (port->closing)
break; /* deleting now */
snd_use_lock_use(&port->use_lock);
return port;
}
}
return NULL; /* not found */
}
/* search for the next port - port is locked if found */
struct snd_seq_client_port *snd_seq_port_query_nearest(struct snd_seq_client *client,
struct snd_seq_port_info *pinfo)
{
int num;
struct snd_seq_client_port *port, *found;
bool check_inactive = (pinfo->capability & SNDRV_SEQ_PORT_CAP_INACTIVE);
num = pinfo->addr.port;
found = NULL;
guard(read_lock)(&client->ports_lock);
list_for_each_entry(port, &client->ports_list_head, list) {
if ((port->capability & SNDRV_SEQ_PORT_CAP_INACTIVE) &&
!check_inactive)
continue; /* skip inactive ports */
if (port->addr.port < num)
continue;
if (port->addr.port == num) {
found = port;
break;
}
if (found == NULL || port->addr.port < found->addr.port)
found = port;
}
if (found) {
if (found->closing)
found = NULL;
else
snd_use_lock_use(&found->use_lock);
}
return found;
}
/* initialize snd_seq_port_subs_info */
static void port_subs_info_init(struct snd_seq_port_subs_info *grp)
{
INIT_LIST_HEAD(&grp->list_head);
grp->count = 0;
grp->exclusive = 0;
rwlock_init(&grp->list_lock);
init_rwsem(&grp->list_mutex);
grp->open = NULL;
grp->close = NULL;
}
/* create a port, port number or a negative error code is returned
* the caller needs to unref the port via snd_seq_port_unlock() appropriately
*/
int snd_seq_create_port(struct snd_seq_client *client, int port,
struct snd_seq_client_port **port_ret)
{
struct snd_seq_client_port *new_port, *p;
int num;
*port_ret = NULL;
/* sanity check */
if (snd_BUG_ON(!client))
return -EINVAL;
if (client->num_ports >= SNDRV_SEQ_MAX_PORTS) {
pr_warn("ALSA: seq: too many ports for client %d\n", client->number);
return -EINVAL;
}
/* create a new port */
new_port = kzalloc(sizeof(*new_port), GFP_KERNEL);
if (!new_port)
return -ENOMEM; /* failure, out of memory */
/* init port data */
new_port->addr.client = client->number;
new_port->addr.port = -1;
new_port->owner = THIS_MODULE;
snd_use_lock_init(&new_port->use_lock);
port_subs_info_init(&new_port->c_src);
port_subs_info_init(&new_port->c_dest);
snd_use_lock_use(&new_port->use_lock);
num = max(port, 0);
guard(mutex)(&client->ports_mutex);
guard(write_lock_irq)(&client->ports_lock);
list_for_each_entry(p, &client->ports_list_head, list) {
if (p->addr.port == port) {
kfree(new_port);
return -EBUSY;
}
if (p->addr.port > num)
break;
if (port < 0) /* auto-probe mode */
num = p->addr.port + 1;
}
/* insert the new port */
list_add_tail(&new_port->list, &p->list);
client->num_ports++;
new_port->addr.port = num; /* store the port number in the port */
sprintf(new_port->name, "port-%d", num);
*port_ret = new_port;
return num;
}
/* */
static int subscribe_port(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_port_subs_info *grp,
struct snd_seq_port_subscribe *info, int send_ack);
static int unsubscribe_port(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_port_subs_info *grp,
struct snd_seq_port_subscribe *info, int send_ack);
static struct snd_seq_client_port *get_client_port(struct snd_seq_addr *addr,
struct snd_seq_client **cp)
{
struct snd_seq_client_port *p;
*cp = snd_seq_client_use_ptr(addr->client);
if (*cp) {
p = snd_seq_port_use_ptr(*cp, addr->port);
if (! p) {
snd_seq_client_unlock(*cp);
*cp = NULL;
}
return p;
}
return NULL;
}
static void delete_and_unsubscribe_port(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_subscribers *subs,
bool is_src, bool ack);
static inline struct snd_seq_subscribers *
get_subscriber(struct list_head *p, bool is_src)
{
if (is_src)
return list_entry(p, struct snd_seq_subscribers, src_list);
else
return list_entry(p, struct snd_seq_subscribers, dest_list);
}
/*
* remove all subscribers on the list
* this is called from port_delete, for each src and dest list.
*/
static void clear_subscriber_list(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_port_subs_info *grp,
int is_src)
{
struct list_head *p, *n;
list_for_each_safe(p, n, &grp->list_head) {
struct snd_seq_subscribers *subs;
struct snd_seq_client *c;
struct snd_seq_client_port *aport;
subs = get_subscriber(p, is_src);
if (is_src)
aport = get_client_port(&subs->info.dest, &c);
else
aport = get_client_port(&subs->info.sender, &c);
delete_and_unsubscribe_port(client, port, subs, is_src, false);
if (!aport) {
/* looks like the connected port is being deleted.
* we decrease the counter, and when both ports are deleted
* remove the subscriber info
*/
if (atomic_dec_and_test(&subs->ref_count))
kfree(subs);
continue;
}
/* ok we got the connected port */
delete_and_unsubscribe_port(c, aport, subs, !is_src, true);
kfree(subs);
snd_seq_port_unlock(aport);
snd_seq_client_unlock(c);
}
}
/* delete port data */
static int port_delete(struct snd_seq_client *client,
struct snd_seq_client_port *port)
{
/* set closing flag and wait for all port access are gone */
port->closing = 1;
snd_use_lock_sync(&port->use_lock);
/* clear subscribers info */
clear_subscriber_list(client, port, &port->c_src, true);
clear_subscriber_list(client, port, &port->c_dest, false);
if (port->private_free)
port->private_free(port->private_data);
snd_BUG_ON(port->c_src.count != 0);
snd_BUG_ON(port->c_dest.count != 0);
kfree(port);
return 0;
}
/* delete a port with the given port id */
int snd_seq_delete_port(struct snd_seq_client *client, int port)
{
struct snd_seq_client_port *found = NULL, *p;
scoped_guard(mutex, &client->ports_mutex) {
guard(write_lock_irq)(&client->ports_lock);
list_for_each_entry(p, &client->ports_list_head, list) {
if (p->addr.port == port) {
/* ok found. delete from the list at first */
list_del(&p->list);
client->num_ports--;
found = p;
break;
}
}
}
if (found)
return port_delete(client, found);
else
return -ENOENT;
}
/* delete the all ports belonging to the given client */
int snd_seq_delete_all_ports(struct snd_seq_client *client)
{
struct list_head deleted_list;
struct snd_seq_client_port *port, *tmp;
/* move the port list to deleted_list, and
* clear the port list in the client data.
*/
guard(mutex)(&client->ports_mutex);
scoped_guard(write_lock_irq, &client->ports_lock) {
if (!list_empty(&client->ports_list_head)) {
list_add(&deleted_list, &client->ports_list_head);
list_del_init(&client->ports_list_head);
} else {
INIT_LIST_HEAD(&deleted_list);
}
client->num_ports = 0;
}
/* remove each port in deleted_list */
list_for_each_entry_safe(port, tmp, &deleted_list, list) {
list_del(&port->list);
snd_seq_system_client_ev_port_exit(port->addr.client, port->addr.port);
port_delete(client, port);
}
return 0;
}
/* set port info fields */
int snd_seq_set_port_info(struct snd_seq_client_port * port,
struct snd_seq_port_info * info)
{
if (snd_BUG_ON(!port || !info))
return -EINVAL;
/* set port name */
if (info->name[0])
strscpy(port->name, info->name, sizeof(port->name));
/* set capabilities */
port->capability = info->capability;
/* get port type */
port->type = info->type;
/* information about supported channels/voices */
port->midi_channels = info->midi_channels;
port->midi_voices = info->midi_voices;
port->synth_voices = info->synth_voices;
/* timestamping */
port->timestamping = (info->flags & SNDRV_SEQ_PORT_FLG_TIMESTAMP) ? 1 : 0;
port->time_real = (info->flags & SNDRV_SEQ_PORT_FLG_TIME_REAL) ? 1 : 0;
port->time_queue = info->time_queue;
/* UMP direction and group */
port->direction = info->direction;
port->ump_group = info->ump_group;
if (port->ump_group > SNDRV_UMP_MAX_GROUPS)
port->ump_group = 0;
/* fill default port direction */
if (!port->direction) {
if (info->capability & SNDRV_SEQ_PORT_CAP_READ)
port->direction |= SNDRV_SEQ_PORT_DIR_INPUT;
if (info->capability & SNDRV_SEQ_PORT_CAP_WRITE)
port->direction |= SNDRV_SEQ_PORT_DIR_OUTPUT;
}
port->is_midi1 = !!(info->flags & SNDRV_SEQ_PORT_FLG_IS_MIDI1);
return 0;
}
/* get port info fields */
int snd_seq_get_port_info(struct snd_seq_client_port * port,
struct snd_seq_port_info * info)
{
if (snd_BUG_ON(!port || !info))
return -EINVAL;
/* get port name */
strscpy(info->name, port->name, sizeof(info->name));
/* get capabilities */
info->capability = port->capability;
/* get port type */
info->type = port->type;
/* information about supported channels/voices */
info->midi_channels = port->midi_channels;
info->midi_voices = port->midi_voices;
info->synth_voices = port->synth_voices;
/* get subscriber counts */
info->read_use = port->c_src.count;
info->write_use = port->c_dest.count;
/* timestamping */
info->flags = 0;
if (port->timestamping) {
info->flags |= SNDRV_SEQ_PORT_FLG_TIMESTAMP;
if (port->time_real)
info->flags |= SNDRV_SEQ_PORT_FLG_TIME_REAL;
info->time_queue = port->time_queue;
}
if (port->is_midi1)
info->flags |= SNDRV_SEQ_PORT_FLG_IS_MIDI1;
/* UMP direction and group */
info->direction = port->direction;
info->ump_group = port->ump_group;
return 0;
}
/*
* call callback functions (if any):
* the callbacks are invoked only when the first (for connection) or
* the last subscription (for disconnection) is done. Second or later
* subscription results in increment of counter, but no callback is
* invoked.
* This feature is useful if these callbacks are associated with
* initialization or termination of devices (see seq_midi.c).
*/
static int subscribe_port(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_port_subs_info *grp,
struct snd_seq_port_subscribe *info,
int send_ack)
{
int err = 0;
if (!try_module_get(port->owner))
return -EFAULT;
grp->count++;
if (grp->open && grp->count == 1) {
err = grp->open(port->private_data, info);
if (err < 0) {
module_put(port->owner);
grp->count--;
}
}
if (err >= 0 && send_ack && client->type == USER_CLIENT)
snd_seq_client_notify_subscription(port->addr.client, port->addr.port,
info, SNDRV_SEQ_EVENT_PORT_SUBSCRIBED);
return err;
}
static int unsubscribe_port(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_port_subs_info *grp,
struct snd_seq_port_subscribe *info,
int send_ack)
{
int err = 0;
if (! grp->count)
return -EINVAL;
grp->count--;
if (grp->close && grp->count == 0)
err = grp->close(port->private_data, info);
if (send_ack && client->type == USER_CLIENT)
snd_seq_client_notify_subscription(port->addr.client, port->addr.port,
info, SNDRV_SEQ_EVENT_PORT_UNSUBSCRIBED);
module_put(port->owner);
return err;
}
/* check if both addresses are identical */
static inline int addr_match(struct snd_seq_addr *r, struct snd_seq_addr *s)
{
return (r->client == s->client) && (r->port == s->port);
}
/* check the two subscribe info match */
/* if flags is zero, checks only sender and destination addresses */
static int match_subs_info(struct snd_seq_port_subscribe *r,
struct snd_seq_port_subscribe *s)
{
if (addr_match(&r->sender, &s->sender) &&
addr_match(&r->dest, &s->dest)) {
if (r->flags && r->flags == s->flags)
return r->queue == s->queue;
else if (! r->flags)
return 1;
}
return 0;
}
static int check_and_subscribe_port(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_subscribers *subs,
bool is_src, bool exclusive, bool ack)
{
struct snd_seq_port_subs_info *grp;
struct list_head *p;
struct snd_seq_subscribers *s;
int err;
grp = is_src ? &port->c_src : &port->c_dest;
guard(rwsem_write)(&grp->list_mutex);
if (exclusive) {
if (!list_empty(&grp->list_head))
return -EBUSY;
} else {
if (grp->exclusive)
return -EBUSY;
/* check whether already exists */
list_for_each(p, &grp->list_head) {
s = get_subscriber(p, is_src);
if (match_subs_info(&subs->info, &s->info))
return -EBUSY;
}
}
err = subscribe_port(client, port, grp, &subs->info, ack);
if (err < 0) {
grp->exclusive = 0;
return err;
}
/* add to list */
guard(write_lock_irq)(&grp->list_lock);
if (is_src)
list_add_tail(&subs->src_list, &grp->list_head);
else
list_add_tail(&subs->dest_list, &grp->list_head);
grp->exclusive = exclusive;
atomic_inc(&subs->ref_count);
return 0;
}
/* called with grp->list_mutex held */
static void __delete_and_unsubscribe_port(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_subscribers *subs,
bool is_src, bool ack)
{
struct snd_seq_port_subs_info *grp;
struct list_head *list;
bool empty;
grp = is_src ? &port->c_src : &port->c_dest;
list = is_src ? &subs->src_list : &subs->dest_list;
scoped_guard(write_lock_irq, &grp->list_lock) {
empty = list_empty(list);
if (!empty)
list_del_init(list);
grp->exclusive = 0;
}
if (!empty)
unsubscribe_port(client, port, grp, &subs->info, ack);
}
static void delete_and_unsubscribe_port(struct snd_seq_client *client,
struct snd_seq_client_port *port,
struct snd_seq_subscribers *subs,
bool is_src, bool ack)
{
struct snd_seq_port_subs_info *grp;
grp = is_src ? &port->c_src : &port->c_dest;
guard(rwsem_write)(&grp->list_mutex);
__delete_and_unsubscribe_port(client, port, subs, is_src, ack);
}
/* connect two ports */
int snd_seq_port_connect(struct snd_seq_client *connector,
struct snd_seq_client *src_client,
struct snd_seq_client_port *src_port,
struct snd_seq_client *dest_client,
struct snd_seq_client_port *dest_port,
struct snd_seq_port_subscribe *info)
{
struct snd_seq_subscribers *subs;
bool exclusive;
int err;
subs = kzalloc(sizeof(*subs), GFP_KERNEL);
if (!subs)
return -ENOMEM;
subs->info = *info;
atomic_set(&subs->ref_count, 0);
INIT_LIST_HEAD(&subs->src_list);
INIT_LIST_HEAD(&subs->dest_list);
exclusive = !!(info->flags & SNDRV_SEQ_PORT_SUBS_EXCLUSIVE);
err = check_and_subscribe_port(src_client, src_port, subs, true,
exclusive,
connector->number != src_client->number);
if (err < 0)
goto error;
err = check_and_subscribe_port(dest_client, dest_port, subs, false,
exclusive,
connector->number != dest_client->number);
if (err < 0)
goto error_dest;
return 0;
error_dest:
delete_and_unsubscribe_port(src_client, src_port, subs, true,
connector->number != src_client->number);
error:
kfree(subs);
return err;
}
/* remove the connection */
int snd_seq_port_disconnect(struct snd_seq_client *connector,
struct snd_seq_client *src_client,
struct snd_seq_client_port *src_port,
struct snd_seq_client *dest_client,
struct snd_seq_client_port *dest_port,
struct snd_seq_port_subscribe *info)
{
struct snd_seq_port_subs_info *dest = &dest_port->c_dest;
struct snd_seq_subscribers *subs;
int err = -ENOENT;
/* always start from deleting the dest port for avoiding concurrent
* deletions
*/
scoped_guard(rwsem_write, &dest->list_mutex) {
/* look for the connection */
list_for_each_entry(subs, &dest->list_head, dest_list) {
if (match_subs_info(info, &subs->info)) {
__delete_and_unsubscribe_port(dest_client, dest_port,
subs, false,
connector->number != dest_client->number);
err = 0;
break;
}
}
}
if (err < 0)
return err;
delete_and_unsubscribe_port(src_client, src_port, subs, true,
connector->number != src_client->number);
kfree(subs);
return 0;
}
/* get matched subscriber */
int snd_seq_port_get_subscription(struct snd_seq_port_subs_info *src_grp,
struct snd_seq_addr *dest_addr,
struct snd_seq_port_subscribe *subs)
{
struct snd_seq_subscribers *s;
int err = -ENOENT;
guard(rwsem_read)(&src_grp->list_mutex);
list_for_each_entry(s, &src_grp->list_head, src_list) {
if (addr_match(dest_addr, &s->info.dest)) {
*subs = s->info;
err = 0;
break;
}
}
return err;
}
/*
* Attach a device driver that wants to receive events from the
* sequencer. Returns the new port number on success.
* A driver that wants to receive the events converted to midi, will
* use snd_seq_midisynth_register_port().
*/
/* exported */
int snd_seq_event_port_attach(int client,
struct snd_seq_port_callback *pcbp,
int cap, int type, int midi_channels,
int midi_voices, char *portname)
{
struct snd_seq_port_info portinfo;
int ret;
/* Set up the port */
memset(&portinfo, 0, sizeof(portinfo));
portinfo.addr.client = client;
strscpy(portinfo.name, portname ? portname : "Unnamed port",
sizeof(portinfo.name));
portinfo.capability = cap;
portinfo.type = type;
portinfo.kernel = pcbp;
portinfo.midi_channels = midi_channels;
portinfo.midi_voices = midi_voices;
/* Create it */
ret = snd_seq_kernel_client_ctl(client,
SNDRV_SEQ_IOCTL_CREATE_PORT,
&portinfo);
if (ret >= 0)
ret = portinfo.addr.port;
return ret;
}
EXPORT_SYMBOL(snd_seq_event_port_attach);
/*
* Detach the driver from a port.
*/
/* exported */
int snd_seq_event_port_detach(int client, int port)
{
struct snd_seq_port_info portinfo;
int err;
memset(&portinfo, 0, sizeof(portinfo));
portinfo.addr.client = client;
portinfo.addr.port = port;
err = snd_seq_kernel_client_ctl(client,
SNDRV_SEQ_IOCTL_DELETE_PORT,
&portinfo);
return err;
}
EXPORT_SYMBOL(snd_seq_event_port_detach);
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