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seq_clientmgr.c

/*
 *  ALSA sequencer Client Manager
 *  Copyright (c) 1998-2001 by Frank van de Pol <fvdpol@coil.demon.nl>
 *                             Jaroslav Kysela <perex@perex.cz>
 *                             Takashi Iwai <tiwai@suse.de>
 *
 *
 *   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 <sound/driver.h>
#include <linux/init.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];
}

extern int seq_client_load[];

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_KMOD
      if (!in_interrupt() && current->fs->root) {
            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] && current->fs->root) {
                        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;

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

      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 */
      snd_assert(client != NULL, 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;

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

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

      if (cell->event.type == SNDRV_SEQ_EVENT_NOTE) {
            /* NOTE event:
             * the event cell is re-used as a NOTE-OFF event and
             * enqueued again.
             */
            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_instr_type(ev) ||
                ! snd_seq_ev_is_direct(ev))
                  return -EINVAL;
            break;
      }
      return 0;
}


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

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

      /* only process whole events */
      while (count >= sizeof(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 = 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 */
      snd_assert(client != NULL, return -ENXIO);

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

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

      if (snd_seq_file_flags(file) & SNDRV_SEQ_LFLG_OUTPUT) {

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

      return mask;
}


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


/* SYSTEM_INFO ioctl() */
static int snd_seq_ioctl_system_info(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%2x)\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;

      snd_assert(client != NULL, 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;

      snd_assert(! 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;

      snd_assert(! 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;

      snd_assert(ev != NULL, 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;

      snd_assert(ev != NULL, 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 __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);
}


void snd_seq_info_pool(struct snd_info_buffer *buffer,
                   struct snd_seq_pool *pool, char *space);

/* 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,
      .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);
}

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