seq_clientmgr.c

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/*
 *  ALSA sequencer Client Manager
 *  Copyright (c) 1998-2001 by Frank van de Pol <[email protected]>
 *                             Jaroslav Kysela <[email protected]>
 *                             Takashi Iwai <[email protected]>
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <linux/init.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <linux/kmod.h>

#include <sound/seq_kernel.h>
#include "seq_clientmgr.h"
#include "seq_memory.h"
#include "seq_queue.h"
#include "seq_timer.h"
#include "seq_info.h"
#include "seq_system.h"
#include <sound/seq_device.h>
#ifdef CONFIG_COMPAT
#include <linux/compat.h>
#endif

/* Client Manager

 * this module handles the connections of userland and kernel clients
 * 
 */

/*
 * There are four ranges of client numbers (last two shared):
 * 0..15: global clients
 * 16..127: statically allocated client numbers for cards 0..27
 * 128..191: dynamically allocated client numbers for cards 28..31
 * 128..191: dynamically allocated client numbers for applications
 */

/* number of kernel non-card clients */
#define SNDRV_SEQ_GLOBAL_CLIENTS    16
/* clients per cards, for static clients */
#define SNDRV_SEQ_CLIENTS_PER_CARD  4
/* dynamically allocated client numbers (both kernel drivers and user space) */
#define SNDRV_SEQ_DYNAMIC_CLIENTS_BEGIN 128

#define SNDRV_SEQ_LFLG_INPUT    0x0001
#define SNDRV_SEQ_LFLG_OUTPUT   0x0002
#define SNDRV_SEQ_LFLG_OPEN (SNDRV_SEQ_LFLG_INPUT|SNDRV_SEQ_LFLG_OUTPUT)

static DEFINE_SPINLOCK(clients_lock);
static DEFINE_MUTEX(register_mutex);

/*
 * client table
 */
static char clienttablock[SNDRV_SEQ_MAX_CLIENTS];
static struct snd_seq_client *clienttab[SNDRV_SEQ_MAX_CLIENTS];
static struct snd_seq_usage client_usage;

/*
 * prototypes
 */
static int bounce_error_event(struct snd_seq_client *client,
                  struct snd_seq_event *event,
                  int err, int atomic, int hop);
static int snd_seq_deliver_single_event(struct snd_seq_client *client,
                    struct snd_seq_event *event,
                    int filter, int atomic, int hop);

/*
 */
 
static inline mm_segment_t snd_enter_user(void)
{
    mm_segment_t fs = get_fs();
    set_fs(get_ds());
    return fs;
}

static inline void snd_leave_user(mm_segment_t fs)
{
    set_fs(fs);
}

/*
 */
static inline unsigned short snd_seq_file_flags(struct file *file)
{
        switch (file->f_mode & (FMODE_READ | FMODE_WRITE)) {
        case FMODE_WRITE:
                return SNDRV_SEQ_LFLG_OUTPUT;
        case FMODE_READ:
                return SNDRV_SEQ_LFLG_INPUT;
        default:
                return SNDRV_SEQ_LFLG_OPEN;
        }
}

static inline int snd_seq_write_pool_allocated(struct snd_seq_client *client)
{
    return snd_seq_total_cells(client->pool) > 0;
}

/* return pointer to client structure for specified id */
static struct snd_seq_client *clientptr(int clientid)
{
    if (clientid < 0 || clientid >= SNDRV_SEQ_MAX_CLIENTS) {
        snd_printd("Seq: oops. Trying to get pointer to client %d\n",
               clientid);
        return NULL;
    }
    return clienttab[clientid];
}

struct snd_seq_client *snd_seq_client_use_ptr(int clientid)
{
    unsigned long flags;
    struct snd_seq_client *client;

    if (clientid < 0 || clientid >= SNDRV_SEQ_MAX_CLIENTS) {
        snd_printd("Seq: oops. Trying to get pointer to client %d\n",
               clientid);
        return NULL;
    }
    spin_lock_irqsave(&clients_lock, flags);
    client = clientptr(clientid);
    if (client)
        goto __lock;
    if (clienttablock[clientid]) {
        spin_unlock_irqrestore(&clients_lock, flags);
        return NULL;
    }
    spin_unlock_irqrestore(&clients_lock, flags);
#ifdef CONFIG_MODULES
    if (!in_interrupt()) {
        static char client_requested[SNDRV_SEQ_GLOBAL_CLIENTS];
        static char card_requested[SNDRV_CARDS];
        if (clientid < SNDRV_SEQ_GLOBAL_CLIENTS) {
            int idx;
            
            if (!client_requested[clientid]) {
                client_requested[clientid] = 1;
                for (idx = 0; idx < 15; idx++) {
                    if (seq_client_load[idx] < 0)
                        break;
                    if (seq_client_load[idx] == clientid) {
                        request_module("snd-seq-client-%i",
                                   clientid);
                        break;
                    }
                }
            }
        } else if (clientid < SNDRV_SEQ_DYNAMIC_CLIENTS_BEGIN) {
            int card = (clientid - SNDRV_SEQ_GLOBAL_CLIENTS) /
                SNDRV_SEQ_CLIENTS_PER_CARD;
            if (card < snd_ecards_limit) {
                if (! card_requested[card]) {
                    card_requested[card] = 1;
                    snd_request_card(card);
                }
                snd_seq_device_load_drivers();
            }
        }
        spin_lock_irqsave(&clients_lock, flags);
        client = clientptr(clientid);
        if (client)
            goto __lock;
        spin_unlock_irqrestore(&clients_lock, flags);
    }
#endif
    return NULL;

      __lock:
    snd_use_lock_use(&client->use_lock);
    spin_unlock_irqrestore(&clients_lock, flags);
    return client;
}

static void usage_alloc(struct snd_seq_usage *res, int num)
{
    res->cur += num;
    if (res->cur > res->peak)
        res->peak = res->cur;
}

static void usage_free(struct snd_seq_usage *res, int num)
{
    res->cur -= num;
}

/* initialise data structures */
int __init client_init_data(void)
{
    /* zap out the client table */
    memset(&clienttablock, 0, sizeof(clienttablock));
    memset(&clienttab, 0, sizeof(clienttab));
    return 0;
}


static struct snd_seq_client *seq_create_client1(int client_index, int poolsize)
{
    unsigned long flags;
    int c;
    struct snd_seq_client *client;

    /* init client data */
    client = kzalloc(sizeof(*client), GFP_KERNEL);
    if (client == NULL)
        return NULL;
    client->pool = snd_seq_pool_new(poolsize);
    if (client->pool == NULL) {
        kfree(client);
        return NULL;
    }
    client->type = NO_CLIENT;
    snd_use_lock_init(&client->use_lock);
    rwlock_init(&client->ports_lock);
    mutex_init(&client->ports_mutex);
    INIT_LIST_HEAD(&client->ports_list_head);

    /* find free slot in the client table */
    spin_lock_irqsave(&clients_lock, flags);
    if (client_index < 0) {
        for (c = SNDRV_SEQ_DYNAMIC_CLIENTS_BEGIN;
             c < SNDRV_SEQ_MAX_CLIENTS;
             c++) {
            if (clienttab[c] || clienttablock[c])
                continue;
            clienttab[client->number = c] = client;
            spin_unlock_irqrestore(&clients_lock, flags);
            return client;
        }
    } else {
        if (clienttab[client_index] == NULL && !clienttablock[client_index]) {
            clienttab[client->number = client_index] = client;
            spin_unlock_irqrestore(&clients_lock, flags);
            return client;
        }
    }
    spin_unlock_irqrestore(&clients_lock, flags);
    snd_seq_pool_delete(&client->pool);
    kfree(client);
    return NULL;    /* no free slot found or busy, return failure code */
}


static int seq_free_client1(struct snd_seq_client *client)
{
    unsigned long flags;

    if (!client)
        return 0;
    snd_seq_delete_all_ports(client);
    snd_seq_queue_client_leave(client->number);
    spin_lock_irqsave(&clients_lock, flags);
    clienttablock[client->number] = 1;
    clienttab[client->number] = NULL;
    spin_unlock_irqrestore(&clients_lock, flags);
    snd_use_lock_sync(&client->use_lock);
    snd_seq_queue_client_termination(client->number);
    if (client->pool)
        snd_seq_pool_delete(&client->pool);
    spin_lock_irqsave(&clients_lock, flags);
    clienttablock[client->number] = 0;
    spin_unlock_irqrestore(&clients_lock, flags);
    return 0;
}


static void seq_free_client(struct snd_seq_client * client)
{
    mutex_lock(&register_mutex);
    switch (client->type) {
    case NO_CLIENT:
        snd_printk(KERN_WARNING "Seq: Trying to free unused client %d\n",
               client->number);
        break;
    case USER_CLIENT:
    case KERNEL_CLIENT:
        seq_free_client1(client);
        usage_free(&client_usage, 1);
        break;

    default:
        snd_printk(KERN_ERR "Seq: Trying to free client %d with undefined type = %d\n",
               client->number, client->type);
    }
    mutex_unlock(&register_mutex);

    snd_seq_system_client_ev_client_exit(client->number);
}



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

/* create a user client */
static int snd_seq_open(struct inode *inode, struct file *file)
{
    int c, mode;            /* client id */
    struct snd_seq_client *client;
    struct snd_seq_user_client *user;
    int err;

    err = nonseekable_open(inode, file);
    if (err < 0)
        return err;

    if (mutex_lock_interruptible(&register_mutex))
        return -ERESTARTSYS;
    client = seq_create_client1(-1, SNDRV_SEQ_DEFAULT_EVENTS);
    if (client == NULL) {
        mutex_unlock(&register_mutex);
        return -ENOMEM; /* failure code */
    }

    mode = snd_seq_file_flags(file);
    if (mode & SNDRV_SEQ_LFLG_INPUT)
        client->accept_input = 1;
    if (mode & SNDRV_SEQ_LFLG_OUTPUT)
        client->accept_output = 1;

    user = &client->data.user;
    user->fifo = NULL;
    user->fifo_pool_size = 0;

    if (mode & SNDRV_SEQ_LFLG_INPUT) {
        user->fifo_pool_size = SNDRV_SEQ_DEFAULT_CLIENT_EVENTS;
        user->fifo = snd_seq_fifo_new(user->fifo_pool_size);
        if (user->fifo == NULL) {
            seq_free_client1(client);
            kfree(client);
            mutex_unlock(&register_mutex);
            return -ENOMEM;
        }
    }

    usage_alloc(&client_usage, 1);
    client->type = USER_CLIENT;
    mutex_unlock(&register_mutex);

    c = client->number;
    file->private_data = client;

    /* fill client data */
    user->file = file;
    sprintf(client->name, "Client-%d", c);

    /* make others aware this new client */
    snd_seq_system_client_ev_client_start(c);

    return 0;
}

/* delete a user client */
static int snd_seq_release(struct inode *inode, struct file *file)
{
    struct snd_seq_client *client = file->private_data;

    if (client) {
        seq_free_client(client);
        if (client->data.user.fifo)
            snd_seq_fifo_delete(&client->data.user.fifo);
        kfree(client);
    }

    return 0;
}


/* handle client read() */
/* possible error values:
 *  -ENXIO  invalid client or file open mode
 *  -ENOSPC FIFO overflow (the flag is cleared after this error report)
 *  -EINVAL no enough user-space buffer to write the whole event
 *  -EFAULT seg. fault during copy to user space
 */
static ssize_t snd_seq_read(struct file *file, char __user *buf, size_t count,
                loff_t *offset)
{
    struct snd_seq_client *client = file->private_data;
    struct snd_seq_fifo *fifo;
    int err;
    long result = 0;
    struct snd_seq_event_cell *cell;

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

    if (!access_ok(VERIFY_WRITE, buf, count))
        return -EFAULT;

    /* check client structures are in place */
    if (snd_BUG_ON(!client))
        return -ENXIO;

    if (!client->accept_input || (fifo = client->data.user.fifo) == NULL)
        return -ENXIO;

    if (atomic_read(&fifo->overflow) > 0) {
        /* buffer overflow is detected */
        snd_seq_fifo_clear(fifo);
        /* return error code */
        return -ENOSPC;
    }

    cell = NULL;
    err = 0;
    snd_seq_fifo_lock(fifo);

    /* while data available in queue */
    while (count >= sizeof(struct snd_seq_event)) {
        int nonblock;

        nonblock = (file->f_flags & O_NONBLOCK) || result > 0;
        if ((err = snd_seq_fifo_cell_out(fifo, &cell, nonblock)) < 0) {
            break;
        }
        if (snd_seq_ev_is_variable(&cell->event)) {
            struct snd_seq_event tmpev;
            tmpev = cell->event;
            tmpev.data.ext.len &= ~SNDRV_SEQ_EXT_MASK;
            if (copy_to_user(buf, &tmpev, sizeof(struct snd_seq_event))) {
                err = -EFAULT;
                break;
            }
            count -= sizeof(struct snd_seq_event);
            buf += sizeof(struct snd_seq_event);
            err = snd_seq_expand_var_event(&cell->event, count,
                               (char __force *)buf, 0,
                               sizeof(struct snd_seq_event));
            if (err < 0)
                break;
            result += err;
            count -= err;
            buf += err;
        } else {
            if (copy_to_user(buf, &cell->event, sizeof(struct snd_seq_event))) {
                err = -EFAULT;
                break;
            }
            count -= sizeof(struct snd_seq_event);
            buf += sizeof(struct snd_seq_event);
        }
        snd_seq_cell_free(cell);
        cell = NULL; /* to be sure */
        result += sizeof(struct snd_seq_event);
    }

    if (err < 0) {
        if (cell)
            snd_seq_fifo_cell_putback(fifo, cell);
        if (err == -EAGAIN && result > 0)
            err = 0;
    }
    snd_seq_fifo_unlock(fifo);

    return (err < 0) ? err : result;
}


/*
 * check access permission to the port
 */
static int check_port_perm(struct snd_seq_client_port *port, unsigned int flags)
{
    if ((port->capability & flags) != flags)
        return 0;
    return flags;
}

/*
 * check if the destination client is available, and return the pointer
 * if filter is non-zero, client filter bitmap is tested.
 */
static struct snd_seq_client *get_event_dest_client(struct snd_seq_event *event,
                            int filter)
{
    struct snd_seq_client *dest;

    dest = snd_seq_client_use_ptr(event->dest.client);
    if (dest == NULL)
        return NULL;
    if (! dest->accept_input)
        goto __not_avail;
    if ((dest->filter & SNDRV_SEQ_FILTER_USE_EVENT) &&
        ! test_bit(event->type, dest->event_filter))
        goto __not_avail;
    if (filter && !(dest->filter & filter))
        goto __not_avail;

    return dest; /* ok - accessible */
__not_avail:
    snd_seq_client_unlock(dest);
    return NULL;
}


/*
 * Return the error event.
 *
 * If the receiver client is a user client, the original event is
 * encapsulated in SNDRV_SEQ_EVENT_BOUNCE as variable length event.  If
 * the original event is also variable length, the external data is
 * copied after the event record. 
 * If the receiver client is a kernel client, the original event is
 * quoted in SNDRV_SEQ_EVENT_KERNEL_ERROR, since this requires no extra
 * kmalloc.
 */
static int bounce_error_event(struct snd_seq_client *client,
                  struct snd_seq_event *event,
                  int err, int atomic, int hop)
{
    struct snd_seq_event bounce_ev;
    int result;

    if (client == NULL ||
        ! (client->filter & SNDRV_SEQ_FILTER_BOUNCE) ||
        ! 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(struct snd_seq_event *event,
                     int queue, int real_time)
{
    struct snd_seq_queue *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(struct snd_seq_client *client,
                    struct snd_seq_event *event,
                    int filter, int atomic, int hop)
{
    struct snd_seq_client *dest = NULL;
    struct snd_seq_client_port *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(struct snd_seq_client *client,
                  struct snd_seq_event *event,
                  int atomic, int hop)
{
    struct snd_seq_subscribers *subs;
    int err = 0, num_ev = 0;
    struct snd_seq_event event_saved;
    struct snd_seq_client_port *src_port;
    struct snd_seq_port_subs_info *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_entry(subs, &grp->list_head, 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(struct snd_seq_client *client,
                struct snd_seq_event *event,
                int atomic, int hop)
{
    int num_ev = 0, err = 0;
    struct snd_seq_client *dest_client;
    struct snd_seq_client_port *port;

    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_entry(port, &dest_client->ports_list_head, 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(struct snd_seq_client *client,
               struct snd_seq_event *event, int atomic, int hop)
{
    int err = 0, num_ev = 0;
    int dest;
    struct snd_seq_addr 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(struct snd_seq_client *client, struct snd_seq_event *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(struct snd_seq_client *client, struct snd_seq_event *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(struct snd_seq_event_cell *cell, int atomic, int hop)
{
    struct snd_seq_client *client;
    int result;

    if (snd_BUG_ON(!cell))
        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.
         */
        struct snd_seq_event 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(struct snd_seq_client *client,
                    struct snd_seq_event *event,
                    struct file *file, int blocking,
                    int atomic, int hop)
{
    struct snd_seq_event_cell *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 */
        struct snd_seq_client_port *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(struct snd_seq_event *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_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)
{
    struct snd_seq_client *client = file->private_data;
    int written = 0, len;
    int err = -EINVAL;
    struct snd_seq_event event;

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

    /* check client structures are in place */
    if (snd_BUG_ON(!client))
        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(struct snd_seq_event)) {
        /* 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;
        }

        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 __force *)buf
                        + sizeof(struct snd_seq_event);
            len += extlen; /* increment data length */
        } else {
#ifdef CONFIG_COMPAT
            if (client->convert32 && snd_seq_ev_is_varusr(&event)) {
                void *ptr = (void __force *)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)
{
    struct snd_seq_client *client = file->private_data;
    unsigned int mask = 0;

    /* check client structures are in place */
    if (snd_BUG_ON(!client))
        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(struct snd_seq_client *client, void __user *arg)
{
    struct snd_seq_system_info 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(struct snd_seq_client *client, void __user *arg)
{
    struct snd_seq_running_info info;
    struct snd_seq_client *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(struct snd_seq_client *cptr,
                struct snd_seq_client_info *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(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_client *cptr;
    struct snd_seq_client_info 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(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_client_info 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(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_client_port *port;
    struct snd_seq_port_info info;
    struct snd_seq_port_callback *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(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_port_info 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(struct snd_seq_client *client,
                       void __user *arg)
{
    struct snd_seq_client *cptr;
    struct snd_seq_client_port *port;
    struct snd_seq_port_info 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(struct snd_seq_client *client,
                       void __user *arg)
{
    struct snd_seq_client_port *port;
    struct snd_seq_port_info 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(struct snd_seq_client *client,
                     struct snd_seq_client_port *sport,
                     struct snd_seq_client_port *dport,
                     struct snd_seq_port_subscribe *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,
                       struct snd_seq_port_subscribe *info,
                       int evtype)
{
    struct snd_seq_event 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(struct snd_seq_client *client,
                    void __user *arg)
{
    int result = -EINVAL;
    struct snd_seq_client *receiver = NULL, *sender = NULL;
    struct snd_seq_client_port *sport = NULL, *dport = NULL;
    struct snd_seq_port_subscribe 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(struct snd_seq_client *client,
                      void __user *arg)
{
    int result = -ENXIO;
    struct snd_seq_client *receiver = NULL, *sender = NULL;
    struct snd_seq_client_port *sport = NULL, *dport = NULL;
    struct snd_seq_port_subscribe 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(struct snd_seq_client *client,
                      void __user *arg)
{
    struct snd_seq_queue_info info;
    int result;
    struct snd_seq_queue *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(struct snd_seq_client *client,
                      void __user *arg)
{
    struct snd_seq_queue_info info;

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

    return snd_seq_queue_delete(client->number, info.queue);
}

/* GET_QUEUE_INFO ioctl() */
static int snd_seq_ioctl_get_queue_info(struct snd_seq_client *client,
                    void __user *arg)
{
    struct snd_seq_queue_info info;
    struct snd_seq_queue *q;

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

    q = queueptr(info.queue);
    if (q == NULL)
        return -EINVAL;

    memset(&info, 0, sizeof(info));
    info.queue = q->queue;
    info.owner = q->owner;
    info.locked = q->locked;
    strlcpy(info.name, q->name, sizeof(info.name));
    queuefree(q);

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

    return 0;
}

/* SET_QUEUE_INFO ioctl() */
static int snd_seq_ioctl_set_queue_info(struct snd_seq_client *client,
                    void __user *arg)
{
    struct snd_seq_queue_info info;
    struct snd_seq_queue *q;

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

    if (info.owner != client->number)
        return -EINVAL;

    /* change owner/locked permission */
    if (snd_seq_queue_check_access(info.queue, client->number)) {
        if (snd_seq_queue_set_owner(info.queue, client->number, info.locked) < 0)
            return -EPERM;
        if (info.locked)
            snd_seq_queue_use(info.queue, client->number, 1);
    } else {
        return -EPERM;
    }   

    q = queueptr(info.queue);
    if (! q)
        return -EINVAL;
    if (q->owner != client->number) {
        queuefree(q);
        return -EPERM;
    }
    strlcpy(q->name, info.name, sizeof(q->name));
    queuefree(q);

    return 0;
}

/* GET_NAMED_QUEUE ioctl() */
static int snd_seq_ioctl_get_named_queue(struct snd_seq_client *client, void __user *arg)
{
    struct snd_seq_queue_info info;
    struct snd_seq_queue *q;

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

    q = snd_seq_queue_find_name(info.name);
    if (q == NULL)
        return -EINVAL;
    info.queue = q->queue;
    info.owner = q->owner;
    info.locked = q->locked;
    queuefree(q);

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

    return 0;
}

/* GET_QUEUE_STATUS ioctl() */
static int snd_seq_ioctl_get_queue_status(struct snd_seq_client *client,
                      void __user *arg)
{
    struct snd_seq_queue_status status;
    struct snd_seq_queue *queue;
    struct snd_seq_timer *tmr;

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

    queue = queueptr(status.queue);
    if (queue == NULL)
        return -EINVAL;
    memset(&status, 0, sizeof(status));
    status.queue = queue->queue;
    
    tmr = queue->timer;
    status.events = queue->tickq->cells + queue->timeq->cells;

    status.time = snd_seq_timer_get_cur_time(tmr);
    status.tick = snd_seq_timer_get_cur_tick(tmr);

    status.running = tmr->running;

    status.flags = queue->flags;
    queuefree(queue);

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


/* GET_QUEUE_TEMPO ioctl() */
static int snd_seq_ioctl_get_queue_tempo(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_queue_tempo tempo;
    struct snd_seq_queue *queue;
    struct snd_seq_timer *tmr;

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

    queue = queueptr(tempo.queue);
    if (queue == NULL)
        return -EINVAL;
    memset(&tempo, 0, sizeof(tempo));
    tempo.queue = queue->queue;
    
    tmr = queue->timer;

    tempo.tempo = tmr->tempo;
    tempo.ppq = tmr->ppq;
    tempo.skew_value = tmr->skew;
    tempo.skew_base = tmr->skew_base;
    queuefree(queue);

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


/* SET_QUEUE_TEMPO ioctl() */
int snd_seq_set_queue_tempo(int client, struct snd_seq_queue_tempo *tempo)
{
    if (!snd_seq_queue_check_access(tempo->queue, client))
        return -EPERM;
    return snd_seq_queue_timer_set_tempo(tempo->queue, client, tempo);
}

EXPORT_SYMBOL(snd_seq_set_queue_tempo);

static int snd_seq_ioctl_set_queue_tempo(struct snd_seq_client *client,
                     void __user *arg)
{
    int result;
    struct snd_seq_queue_tempo tempo;

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

    result = snd_seq_set_queue_tempo(client->number, &tempo);
    return result < 0 ? result : 0;
}


/* GET_QUEUE_TIMER ioctl() */
static int snd_seq_ioctl_get_queue_timer(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_queue_timer timer;
    struct snd_seq_queue *queue;
    struct snd_seq_timer *tmr;

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

    queue = queueptr(timer.queue);
    if (queue == NULL)
        return -EINVAL;

    if (mutex_lock_interruptible(&queue->timer_mutex)) {
        queuefree(queue);
        return -ERESTARTSYS;
    }
    tmr = queue->timer;
    memset(&timer, 0, sizeof(timer));
    timer.queue = queue->queue;

    timer.type = tmr->type;
    if (tmr->type == SNDRV_SEQ_TIMER_ALSA) {
        timer.u.alsa.id = tmr->alsa_id;
        timer.u.alsa.resolution = tmr->preferred_resolution;
    }
    mutex_unlock(&queue->timer_mutex);
    queuefree(queue);
    
    if (copy_to_user(arg, &timer, sizeof(timer)))
        return -EFAULT;
    return 0;
}


/* SET_QUEUE_TIMER ioctl() */
static int snd_seq_ioctl_set_queue_timer(struct snd_seq_client *client,
                     void __user *arg)
{
    int result = 0;
    struct snd_seq_queue_timer timer;

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

    if (timer.type != SNDRV_SEQ_TIMER_ALSA)
        return -EINVAL;

    if (snd_seq_queue_check_access(timer.queue, client->number)) {
        struct snd_seq_queue *q;
        struct snd_seq_timer *tmr;

        q = queueptr(timer.queue);
        if (q == NULL)
            return -ENXIO;
        if (mutex_lock_interruptible(&q->timer_mutex)) {
            queuefree(q);
            return -ERESTARTSYS;
        }
        tmr = q->timer;
        snd_seq_queue_timer_close(timer.queue);
        tmr->type = timer.type;
        if (tmr->type == SNDRV_SEQ_TIMER_ALSA) {
            tmr->alsa_id = timer.u.alsa.id;
            tmr->preferred_resolution = timer.u.alsa.resolution;
        }
        result = snd_seq_queue_timer_open(timer.queue);
        mutex_unlock(&q->timer_mutex);
        queuefree(q);
    } else {
        return -EPERM;
    }   

    return result;
}


/* GET_QUEUE_CLIENT ioctl() */
static int snd_seq_ioctl_get_queue_client(struct snd_seq_client *client,
                      void __user *arg)
{
    struct snd_seq_queue_client info;
    int used;

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

    used = snd_seq_queue_is_used(info.queue, client->number);
    if (used < 0)
        return -EINVAL;
    info.used = used;
    info.client = client->number;

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


/* SET_QUEUE_CLIENT ioctl() */
static int snd_seq_ioctl_set_queue_client(struct snd_seq_client *client,
                      void __user *arg)
{
    int err;
    struct snd_seq_queue_client info;

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

    if (info.used >= 0) {
        err = snd_seq_queue_use(info.queue, client->number, info.used);
        if (err < 0)
            return err;
    }

    return snd_seq_ioctl_get_queue_client(client, arg);
}


/* GET_CLIENT_POOL ioctl() */
static int snd_seq_ioctl_get_client_pool(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_client_pool info;
    struct snd_seq_client *cptr;

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

    cptr = snd_seq_client_use_ptr(info.client);
    if (cptr == NULL)
        return -ENOENT;
    memset(&info, 0, sizeof(info));
    info.output_pool = cptr->pool->size;
    info.output_room = cptr->pool->room;
    info.output_free = info.output_pool;
    info.output_free = snd_seq_unused_cells(cptr->pool);
    if (cptr->type == USER_CLIENT) {
        info.input_pool = cptr->data.user.fifo_pool_size;
        info.input_free = info.input_pool;
        if (cptr->data.user.fifo)
            info.input_free = snd_seq_unused_cells(cptr->data.user.fifo->pool);
    } else {
        info.input_pool = 0;
        info.input_free = 0;
    }
    snd_seq_client_unlock(cptr);
    
    if (copy_to_user(arg, &info, sizeof(info)))
        return -EFAULT;
    return 0;
}

/* SET_CLIENT_POOL ioctl() */
static int snd_seq_ioctl_set_client_pool(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_client_pool info;
    int rc;

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

    if (client->number != info.client)
        return -EINVAL; /* can't change other clients */

    if (info.output_pool >= 1 && info.output_pool <= SNDRV_SEQ_MAX_EVENTS &&
        (! snd_seq_write_pool_allocated(client) ||
         info.output_pool != client->pool->size)) {
        if (snd_seq_write_pool_allocated(client)) {
            /* remove all existing cells */
            snd_seq_queue_client_leave_cells(client->number);
            snd_seq_pool_done(client->pool);
        }
        client->pool->size = info.output_pool;
        rc = snd_seq_pool_init(client->pool);
        if (rc < 0)
            return rc;
    }
    if (client->type == USER_CLIENT && client->data.user.fifo != NULL &&
        info.input_pool >= 1 &&
        info.input_pool <= SNDRV_SEQ_MAX_CLIENT_EVENTS &&
        info.input_pool != client->data.user.fifo_pool_size) {
        /* change pool size */
        rc = snd_seq_fifo_resize(client->data.user.fifo, info.input_pool);
        if (rc < 0)
            return rc;
        client->data.user.fifo_pool_size = info.input_pool;
    }
    if (info.output_room >= 1 &&
        info.output_room <= client->pool->size) {
        client->pool->room  = info.output_room;
    }

    return snd_seq_ioctl_get_client_pool(client, arg);
}


/* REMOVE_EVENTS ioctl() */
static int snd_seq_ioctl_remove_events(struct snd_seq_client *client,
                       void __user *arg)
{
    struct snd_seq_remove_events info;

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

    /*
     * Input mostly not implemented XXX.
     */
    if (info.remove_mode & SNDRV_SEQ_REMOVE_INPUT) {
        /*
         * No restrictions so for a user client we can clear
         * the whole fifo
         */
        if (client->type == USER_CLIENT)
            snd_seq_fifo_clear(client->data.user.fifo);
    }

    if (info.remove_mode & SNDRV_SEQ_REMOVE_OUTPUT)
        snd_seq_queue_remove_cells(client->number, &info);

    return 0;
}


/*
 * get subscription info
 */
static int snd_seq_ioctl_get_subscription(struct snd_seq_client *client,
                      void __user *arg)
{
    int result;
    struct snd_seq_client *sender = NULL;
    struct snd_seq_client_port *sport = NULL;
    struct snd_seq_port_subscribe subs;
    struct snd_seq_subscribers *p;

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

    result = -EINVAL;
    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;
    p = snd_seq_port_get_subscription(&sport->c_src, &subs.dest);
    if (p) {
        result = 0;
        subs = p->info;
    } else
        result = -ENOENT;

      __end:
        if (sport)
        snd_seq_port_unlock(sport);
    if (sender)
        snd_seq_client_unlock(sender);
    if (result >= 0) {
        if (copy_to_user(arg, &subs, sizeof(subs)))
            return -EFAULT;
    }
    return result;
}


/*
 * get subscription info - check only its presence
 */
static int snd_seq_ioctl_query_subs(struct snd_seq_client *client,
                    void __user *arg)
{
    int result = -ENXIO;
    struct snd_seq_client *cptr = NULL;
    struct snd_seq_client_port *port = NULL;
    struct snd_seq_query_subs subs;
    struct snd_seq_port_subs_info *group;
    struct list_head *p;
    int i;

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

    if ((cptr = snd_seq_client_use_ptr(subs.root.client)) == NULL)
        goto __end;
    if ((port = snd_seq_port_use_ptr(cptr, subs.root.port)) == NULL)
        goto __end;

    switch (subs.type) {
    case SNDRV_SEQ_QUERY_SUBS_READ:
        group = &port->c_src;
        break;
    case SNDRV_SEQ_QUERY_SUBS_WRITE:
        group = &port->c_dest;
        break;
    default:
        goto __end;
    }

    down_read(&group->list_mutex);
    /* search for the subscriber */
    subs.num_subs = group->count;
    i = 0;
    result = -ENOENT;
    list_for_each(p, &group->list_head) {
        if (i++ == subs.index) {
            /* found! */
            struct snd_seq_subscribers *s;
            if (subs.type == SNDRV_SEQ_QUERY_SUBS_READ) {
                s = list_entry(p, struct snd_seq_subscribers, src_list);
                subs.addr = s->info.dest;
            } else {
                s = list_entry(p, struct snd_seq_subscribers, dest_list);
                subs.addr = s->info.sender;
            }
            subs.flags = s->info.flags;
            subs.queue = s->info.queue;
            result = 0;
            break;
        }
    }
    up_read(&group->list_mutex);

      __end:
    if (port)
        snd_seq_port_unlock(port);
    if (cptr)
        snd_seq_client_unlock(cptr);
    if (result >= 0) {
        if (copy_to_user(arg, &subs, sizeof(subs)))
            return -EFAULT;
    }
    return result;
}


/*
 * query next client
 */
static int snd_seq_ioctl_query_next_client(struct snd_seq_client *client,
                       void __user *arg)
{
    struct snd_seq_client *cptr = NULL;
    struct snd_seq_client_info info;

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

    /* search for next client */
    info.client++;
    if (info.client < 0)
        info.client = 0;
    for (; info.client < SNDRV_SEQ_MAX_CLIENTS; info.client++) {
        cptr = snd_seq_client_use_ptr(info.client);
        if (cptr)
            break; /* found */
    }
    if (cptr == NULL)
        return -ENOENT;

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

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

/* 
 * query next port
 */
static int snd_seq_ioctl_query_next_port(struct snd_seq_client *client,
                     void __user *arg)
{
    struct snd_seq_client *cptr;
    struct snd_seq_client_port *port = NULL;
    struct snd_seq_port_info 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;

    /* search for next port */
    info.addr.port++;
    port = snd_seq_port_query_nearest(cptr, &info);
    if (port == NULL) {
        snd_seq_client_unlock(cptr);
        return -ENOENT;
    }

    /* get port info */
    info.addr = port->addr;
    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;
}

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

static struct seq_ioctl_table {
    unsigned int cmd;
    int (*func)(struct snd_seq_client *client, void __user * arg);
} ioctl_tables[] = {
    { SNDRV_SEQ_IOCTL_SYSTEM_INFO, snd_seq_ioctl_system_info },
    { SNDRV_SEQ_IOCTL_RUNNING_MODE, snd_seq_ioctl_running_mode },
    { SNDRV_SEQ_IOCTL_GET_CLIENT_INFO, snd_seq_ioctl_get_client_info },
    { SNDRV_SEQ_IOCTL_SET_CLIENT_INFO, snd_seq_ioctl_set_client_info },
    { SNDRV_SEQ_IOCTL_CREATE_PORT, snd_seq_ioctl_create_port },
    { SNDRV_SEQ_IOCTL_DELETE_PORT, snd_seq_ioctl_delete_port },
    { SNDRV_SEQ_IOCTL_GET_PORT_INFO, snd_seq_ioctl_get_port_info },
    { SNDRV_SEQ_IOCTL_SET_PORT_INFO, snd_seq_ioctl_set_port_info },
    { SNDRV_SEQ_IOCTL_SUBSCRIBE_PORT, snd_seq_ioctl_subscribe_port },
    { SNDRV_SEQ_IOCTL_UNSUBSCRIBE_PORT, snd_seq_ioctl_unsubscribe_port },
    { SNDRV_SEQ_IOCTL_CREATE_QUEUE, snd_seq_ioctl_create_queue },
    { SNDRV_SEQ_IOCTL_DELETE_QUEUE, snd_seq_ioctl_delete_queue },
    { SNDRV_SEQ_IOCTL_GET_QUEUE_INFO, snd_seq_ioctl_get_queue_info },
    { SNDRV_SEQ_IOCTL_SET_QUEUE_INFO, snd_seq_ioctl_set_queue_info },
    { SNDRV_SEQ_IOCTL_GET_NAMED_QUEUE, snd_seq_ioctl_get_named_queue },
    { SNDRV_SEQ_IOCTL_GET_QUEUE_STATUS, snd_seq_ioctl_get_queue_status },
    { SNDRV_SEQ_IOCTL_GET_QUEUE_TEMPO, snd_seq_ioctl_get_queue_tempo },
    { SNDRV_SEQ_IOCTL_SET_QUEUE_TEMPO, snd_seq_ioctl_set_queue_tempo },
    { SNDRV_SEQ_IOCTL_GET_QUEUE_TIMER, snd_seq_ioctl_get_queue_timer },
    { SNDRV_SEQ_IOCTL_SET_QUEUE_TIMER, snd_seq_ioctl_set_queue_timer },
    { SNDRV_SEQ_IOCTL_GET_QUEUE_CLIENT, snd_seq_ioctl_get_queue_client },
    { SNDRV_SEQ_IOCTL_SET_QUEUE_CLIENT, snd_seq_ioctl_set_queue_client },
    { SNDRV_SEQ_IOCTL_GET_CLIENT_POOL, snd_seq_ioctl_get_client_pool },
    { SNDRV_SEQ_IOCTL_SET_CLIENT_POOL, snd_seq_ioctl_set_client_pool },
    { SNDRV_SEQ_IOCTL_GET_SUBSCRIPTION, snd_seq_ioctl_get_subscription },
    { SNDRV_SEQ_IOCTL_QUERY_NEXT_CLIENT, snd_seq_ioctl_query_next_client },
    { SNDRV_SEQ_IOCTL_QUERY_NEXT_PORT, snd_seq_ioctl_query_next_port },
    { SNDRV_SEQ_IOCTL_REMOVE_EVENTS, snd_seq_ioctl_remove_events },
    { SNDRV_SEQ_IOCTL_QUERY_SUBS, snd_seq_ioctl_query_subs },
    { 0, NULL },
};

static int snd_seq_do_ioctl(struct snd_seq_client *client, unsigned int cmd,
                void __user *arg)
{
    struct seq_ioctl_table *p;

    switch (cmd) {
    case SNDRV_SEQ_IOCTL_PVERSION:
        /* return sequencer version number */
        return put_user(SNDRV_SEQ_VERSION, (int __user *)arg) ? -EFAULT : 0;
    case SNDRV_SEQ_IOCTL_CLIENT_ID:
        /* return the id of this client */
        return put_user(client->number, (int __user *)arg) ? -EFAULT : 0;
    }

    if (! arg)
        return -EFAULT;
    for (p = ioctl_tables; p->cmd; p++) {
        if (p->cmd == cmd)
            return p->func(client, arg);
    }
    snd_printd("seq unknown ioctl() 0x%x (type='%c', number=0x%02x)\n",
           cmd, _IOC_TYPE(cmd), _IOC_NR(cmd));
    return -ENOTTY;
}


static long snd_seq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    struct snd_seq_client *client = file->private_data;

    if (snd_BUG_ON(!client))
        return -ENXIO;
        
    return snd_seq_do_ioctl(client, cmd, (void __user *) arg);
}

#ifdef CONFIG_COMPAT
#include "seq_compat.c"
#else
#define snd_seq_ioctl_compat    NULL
#endif

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


/* exported to kernel modules */
int snd_seq_create_kernel_client(struct snd_card *card, int client_index,
                 const char *name_fmt, ...)
{
    struct snd_seq_client *client;
    va_list args;

    if (snd_BUG_ON(in_interrupt()))
        return -EBUSY;

    if (card && client_index >= SNDRV_SEQ_CLIENTS_PER_CARD)
        return -EINVAL;
    if (card == NULL && client_index >= SNDRV_SEQ_GLOBAL_CLIENTS)
        return -EINVAL;

    if (mutex_lock_interruptible(&register_mutex))
        return -ERESTARTSYS;

    if (card) {
        client_index += SNDRV_SEQ_GLOBAL_CLIENTS
            + card->number * SNDRV_SEQ_CLIENTS_PER_CARD;
        if (client_index >= SNDRV_SEQ_DYNAMIC_CLIENTS_BEGIN)
            client_index = -1;
    }

    /* empty write queue as default */
    client = seq_create_client1(client_index, 0);
    if (client == NULL) {
        mutex_unlock(&register_mutex);
        return -EBUSY;  /* failure code */
    }
    usage_alloc(&client_usage, 1);

    client->accept_input = 1;
    client->accept_output = 1;
        
    va_start(args, name_fmt);
    vsnprintf(client->name, sizeof(client->name), name_fmt, args);
    va_end(args);

    client->type = KERNEL_CLIENT;
    mutex_unlock(&register_mutex);

    /* make others aware this new client */
    snd_seq_system_client_ev_client_start(client->number);
    
    /* return client number to caller */
    return client->number;
}

EXPORT_SYMBOL(snd_seq_create_kernel_client);

/* exported to kernel modules */
int snd_seq_delete_kernel_client(int client)
{
    struct snd_seq_client *ptr;

    if (snd_BUG_ON(in_interrupt()))
        return -EBUSY;

    ptr = clientptr(client);
    if (ptr == NULL)
        return -EINVAL;

    seq_free_client(ptr);
    kfree(ptr);
    return 0;
}

EXPORT_SYMBOL(snd_seq_delete_kernel_client);

/* skeleton to enqueue event, called from snd_seq_kernel_client_enqueue
 * and snd_seq_kernel_client_enqueue_blocking
 */
static int kernel_client_enqueue(int client, struct snd_seq_event *ev,
                 struct file *file, int blocking,
                 int atomic, int hop)
{
    struct snd_seq_client *cptr;
    int result;

    if (snd_BUG_ON(!ev))
        return -EINVAL;

    if (ev->type == SNDRV_SEQ_EVENT_NONE)
        return 0; /* ignore this */
    if (ev->type == SNDRV_SEQ_EVENT_KERNEL_ERROR)
        return -EINVAL; /* quoted events can't be enqueued */

    /* fill in client number */
    ev->source.client = client;

    if (check_event_type_and_length(ev))
        return -EINVAL;

    cptr = snd_seq_client_use_ptr(client);
    if (cptr == NULL)
        return -EINVAL;
    
    if (! cptr->accept_output)
        result = -EPERM;
    else /* send it */
        result = snd_seq_client_enqueue_event(cptr, ev, file, blocking, atomic, hop);

    snd_seq_client_unlock(cptr);
    return result;
}

/*
 * exported, called by kernel clients to enqueue events (w/o blocking)
 *
 * RETURN VALUE: zero if succeed, negative if error
 */
int snd_seq_kernel_client_enqueue(int client, struct snd_seq_event * ev,
                  int atomic, int hop)
{
    return kernel_client_enqueue(client, ev, NULL, 0, atomic, hop);
}

EXPORT_SYMBOL(snd_seq_kernel_client_enqueue);

/*
 * exported, called by kernel clients to enqueue events (with blocking)
 *
 * RETURN VALUE: zero if succeed, negative if error
 */
int snd_seq_kernel_client_enqueue_blocking(int client, struct snd_seq_event * ev,
                       struct file *file,
                       int atomic, int hop)
{
    return kernel_client_enqueue(client, ev, file, 1, atomic, hop);
}

EXPORT_SYMBOL(snd_seq_kernel_client_enqueue_blocking);

/* 
 * exported, called by kernel clients to dispatch events directly to other
 * clients, bypassing the queues.  Event time-stamp will be updated.
 *
 * RETURN VALUE: negative = delivery failed,
 *       zero, or positive: the number of delivered events
 */
int snd_seq_kernel_client_dispatch(int client, struct snd_seq_event * ev,
                   int atomic, int hop)
{
    struct snd_seq_client *cptr;
    int result;

    if (snd_BUG_ON(!ev))
        return -EINVAL;

    /* fill in client number */
    ev->queue = SNDRV_SEQ_QUEUE_DIRECT;
    ev->source.client = client;

    if (check_event_type_and_length(ev))
        return -EINVAL;

    cptr = snd_seq_client_use_ptr(client);
    if (cptr == NULL)
        return -EINVAL;

    if (!cptr->accept_output)
        result = -EPERM;
    else
        result = snd_seq_deliver_event(cptr, ev, atomic, hop);

    snd_seq_client_unlock(cptr);
    return result;
}

EXPORT_SYMBOL(snd_seq_kernel_client_dispatch);

/*
 * exported, called by kernel clients to perform same functions as with
 * userland ioctl() 
 */
int snd_seq_kernel_client_ctl(int clientid, unsigned int cmd, void *arg)
{
    struct snd_seq_client *client;
    mm_segment_t fs;
    int result;

    client = clientptr(clientid);
    if (client == NULL)
        return -ENXIO;
    fs = snd_enter_user();
    result = snd_seq_do_ioctl(client, cmd, (void __force __user *)arg);
    snd_leave_user(fs);
    return result;
}

EXPORT_SYMBOL(snd_seq_kernel_client_ctl);

/* exported (for OSS emulator) */
int snd_seq_kernel_client_write_poll(int clientid, struct file *file, poll_table *wait)
{
    struct snd_seq_client *client;

    client = clientptr(clientid);
    if (client == NULL)
        return -ENXIO;

    if (! snd_seq_write_pool_allocated(client))
        return 1;
    if (snd_seq_pool_poll_wait(client->pool, file, wait))
        return 1;
    return 0;
}

EXPORT_SYMBOL(snd_seq_kernel_client_write_poll);

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

#ifdef CONFIG_PROC_FS
/*
 *  /proc interface
 */
static void snd_seq_info_dump_subscribers(struct snd_info_buffer *buffer,
                      struct snd_seq_port_subs_info *group,
                      int is_src, char *msg)
{
    struct list_head *p;
    struct snd_seq_subscribers *s;
    int count = 0;

    down_read(&group->list_mutex);
    if (list_empty(&group->list_head)) {
        up_read(&group->list_mutex);
        return;
    }
    snd_iprintf(buffer, msg);
    list_for_each(p, &group->list_head) {
        if (is_src)
            s = list_entry(p, struct snd_seq_subscribers, src_list);
        else
            s = list_entry(p, struct snd_seq_subscribers, dest_list);
        if (count++)
            snd_iprintf(buffer, ", ");
        snd_iprintf(buffer, "%d:%d",
                is_src ? s->info.dest.client : s->info.sender.client,
                is_src ? s->info.dest.port : s->info.sender.port);
        if (s->info.flags & SNDRV_SEQ_PORT_SUBS_TIMESTAMP)
            snd_iprintf(buffer, "[%c:%d]", ((s->info.flags & SNDRV_SEQ_PORT_SUBS_TIME_REAL) ? 'r' : 't'), s->info.queue);
        if (group->exclusive)
            snd_iprintf(buffer, "[ex]");
    }
    up_read(&group->list_mutex);
    snd_iprintf(buffer, "\n");
}

#define FLAG_PERM_RD(perm) ((perm) & SNDRV_SEQ_PORT_CAP_READ ? ((perm) & SNDRV_SEQ_PORT_CAP_SUBS_READ ? 'R' : 'r') : '-')
#define FLAG_PERM_WR(perm) ((perm) & SNDRV_SEQ_PORT_CAP_WRITE ? ((perm) & SNDRV_SEQ_PORT_CAP_SUBS_WRITE ? 'W' : 'w') : '-')
#define FLAG_PERM_EX(perm) ((perm) & SNDRV_SEQ_PORT_CAP_NO_EXPORT ? '-' : 'e')

#define FLAG_PERM_DUPLEX(perm) ((perm) & SNDRV_SEQ_PORT_CAP_DUPLEX ? 'X' : '-')

static void snd_seq_info_dump_ports(struct snd_info_buffer *buffer,
                    struct snd_seq_client *client)
{
    struct snd_seq_client_port *p;

    mutex_lock(&client->ports_mutex);
    list_for_each_entry(p, &client->ports_list_head, list) {
        snd_iprintf(buffer, "  Port %3d : \"%s\" (%c%c%c%c)\n",
                p->addr.port, p->name,
                FLAG_PERM_RD(p->capability),
                FLAG_PERM_WR(p->capability),
                FLAG_PERM_EX(p->capability),
                FLAG_PERM_DUPLEX(p->capability));
        snd_seq_info_dump_subscribers(buffer, &p->c_src, 1, "    Connecting To: ");
        snd_seq_info_dump_subscribers(buffer, &p->c_dest, 0, "    Connected From: ");
    }
    mutex_unlock(&client->ports_mutex);
}


/* exported to seq_info.c */
void snd_seq_info_clients_read(struct snd_info_entry *entry, 
                   struct snd_info_buffer *buffer)
{
    int c;
    struct snd_seq_client *client;

    snd_iprintf(buffer, "Client info\n");
    snd_iprintf(buffer, "  cur  clients : %d\n", client_usage.cur);
    snd_iprintf(buffer, "  peak clients : %d\n", client_usage.peak);
    snd_iprintf(buffer, "  max  clients : %d\n", SNDRV_SEQ_MAX_CLIENTS);
    snd_iprintf(buffer, "\n");

    /* list the client table */
    for (c = 0; c < SNDRV_SEQ_MAX_CLIENTS; c++) {
        client = snd_seq_client_use_ptr(c);
        if (client == NULL)
            continue;
        if (client->type == NO_CLIENT) {
            snd_seq_client_unlock(client);
            continue;
        }

        snd_iprintf(buffer, "Client %3d : \"%s\" [%s]\n",
                c, client->name,
                client->type == USER_CLIENT ? "User" : "Kernel");
        snd_seq_info_dump_ports(buffer, client);
        if (snd_seq_write_pool_allocated(client)) {
            snd_iprintf(buffer, "  Output pool :\n");
            snd_seq_info_pool(buffer, client->pool, "    ");
        }
        if (client->type == USER_CLIENT && client->data.user.fifo &&
            client->data.user.fifo->pool) {
            snd_iprintf(buffer, "  Input pool :\n");
            snd_seq_info_pool(buffer, client->data.user.fifo->pool, "    ");
        }
        snd_seq_client_unlock(client);
    }
}
#endif /* CONFIG_PROC_FS */

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


/*
 *  REGISTRATION PART
 */

static const struct file_operations snd_seq_f_ops =
{
    .owner =    THIS_MODULE,
    .read =     snd_seq_read,
    .write =    snd_seq_write,
    .open =     snd_seq_open,
    .release =  snd_seq_release,
    .llseek =   no_llseek,
    .poll =     snd_seq_poll,
    .unlocked_ioctl =   snd_seq_ioctl,
    .compat_ioctl = snd_seq_ioctl_compat,
};

/* 
 * register sequencer device 
 */
int __init snd_sequencer_device_init(void)
{
    int err;

    if (mutex_lock_interruptible(&register_mutex))
        return -ERESTARTSYS;

    if ((err = snd_register_device(SNDRV_DEVICE_TYPE_SEQUENCER, NULL, 0,
                       &snd_seq_f_ops, NULL, "seq")) < 0) {
        mutex_unlock(&register_mutex);
        return err;
    }
    
    mutex_unlock(&register_mutex);

    return 0;
}



/* 
 * unregister sequencer device 
 */
void __exit snd_sequencer_device_done(void)
{
    snd_unregister_device(SNDRV_DEVICE_TYPE_SEQUENCER, NULL, 0);
}