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/*

 * Project: S.Ha.R.K.

 *

 * Coordinators:

 *   Giorgio Buttazzo    <giorgio@sssup.it>

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *

 * Authors     :

 *   Paolo Gai           <pj@gandalf.sssup.it>

 *   (see the web pages for full authors list)

 *

 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)

 *

 * http://www.sssup.it

 * http://retis.sssup.it

 * http://shark.sssup.it

 */

/**

 ------------

 CVS :        $Id: mqueue.c,v 1.4 2003-11-05 15:05:11 giacomo Exp $

 File:        $File$

 Revision:    $Revision: 1.4 $

 Last update: $Date: 2003-11-05 15:05:11 $

 ------------

 POSIX message queues

**/

/*

 * Copyright (C) 2000 Paolo Gai

 *

 * 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 <mqueue.h>

#include <ll/string.h>

#include <kernel/types.h>

#include <kernel/var.h>

#include <kernel/func.h>

#include <errno.h>

#include <stdarg.h>

#include <pthread.h>

#include <sys/types.h>

/* some flags... */

#define MQ_USED                 1

#define MQ_NONBLOCK             2

#define MQ_NOTIFICATION_PRESENT 4

static int mq_once = 1;

struct mq_elem {

  unsigned int mq_prio;   /* the priority of a message */

  ssize_t msglen;         /* the length of a message   */

  int next;               /* the priority queue        */

};

/* Semaphores descriptor tables */

static struct mq_des {

    char *name;              /* a name */

    int  flags;              /* flags... */

    long maxmsg;             /* maximum number of messages */

    long msgsize;            /* Maximum message size */

    long count;              /* Number of messages currently queued */

    long start;              /* first not-empty message */

    BYTE *mq_data;           /* the data... */

    struct mq_elem *mq_info; /* the priorities */

    int mq_first;            /* the first empty message */

    struct sigevent notification; /* the notification, valid only if the

                                     correct bit is set */

    /* the blocked processes queues */

    IQUEUE blocked_send;

    IQUEUE blocked_rcv;

    int next;            /* the mq queue */

} mq_table[MQ_OPEN_MAX];

/* this -IS- an extension to the proc_table!!! */

static struct {

    int intsig;   /* Normally it is =0, -1 only when a task is woken up

                     by a signal */

    int mqdes;    /* message queue on which a task is blocked (meaningless

                     if the task is not blocked...) */

} mqproc_table[MAX_PROC];

static int free_mq;         /* Queue of free sem                    */

mqd_t mq_open(const char *name, int oflag, ...)

{

    int     i;

    int     found = 0;

    mode_t  m;

    mqd_t   mq;

    struct mq_attr *attr;

    SYS_FLAGS f;

    f = kern_fsave();

    for (i = 0; i < MQ_OPEN_MAX; i++)

      if (mq_table[i].flags & MQ_USED) {

        if (strcmp((char*)name, mq_table[i].name) == 0) {

          found = 1;

          break;

        }

      }

    if (found) {

      if (oflag == (O_CREAT | O_EXCL)) {

          errno = EEXIST;

          kern_frestore(f);

          return -1;

      } else {

          kern_frestore(f);

          return i;

      }

    } else {

      if (!(oflag & O_CREAT)) {

          errno = ENOENT;

          kern_frestore(f);

          return -1;

      } else if (!(oflag & O_RDWR)) {

          errno = EACCES;

          kern_frestore(f);

          return -1;

      } else {

          va_list l;

          va_start(l, oflag);

            m = va_arg(l,mode_t);

            attr = va_arg(l, struct mq_attr *);

          va_end(l);

          mq = free_mq;

          if (mq != -1) {

            mq_table[mq].name = kern_alloc(strlen((char *)name)+1);

            if (!mq_table[mq].name) {

              errno = ENOSPC;

              kern_frestore(f);

              return -1;

            }

            strcpy(mq_table[mq].name, (char *)name);

            if (attr) {

              mq_table[mq].maxmsg  = attr->mq_maxmsg;

              mq_table[mq].msgsize = attr->mq_msgsize;

            }

            else {

              mq_table[mq].maxmsg  = MQ_DEFAULT_MAXMSG;

              mq_table[mq].msgsize = MQ_DEFAULT_MSGSIZE;

            }

            iq_init(&mq_table[mq].blocked_send, &freedesc, 0);

            iq_init(&mq_table[mq].blocked_rcv, &freedesc, 0);

            mq_table[mq].count = 0;

            mq_table[mq].start = -1;

            mq_table[mq].mq_first = 0;

            if (oflag & O_NONBLOCK)

              mq_table[mq].flags = MQ_USED | MQ_NONBLOCK;

            else

              mq_table[mq].flags = MQ_USED;

            mq_table[mq].mq_data = (BYTE *)

              kern_alloc(mq_table[mq].maxmsg * mq_table[mq].msgsize);

            if (!mq_table[mq].mq_data) {

              kern_free(mq_table[mq].name,strlen((char *)name)+1);

              errno = ENOSPC;

              kern_frestore(f);

              return -1;

            }

            mq_table[mq].mq_info = (struct mq_elem *)

              kern_alloc(mq_table[mq].maxmsg * sizeof(struct mq_elem));

            if (!mq_table[mq].mq_info) {

              kern_free(mq_table[mq].name,strlen((char *)name)+1);

              kern_free(mq_table[mq].mq_data,

                        mq_table[mq].maxmsg * mq_table[mq].msgsize);

              errno = ENOSPC;

              kern_frestore(f);

              return -1;

            }

            /* set up the element queue */

            for (i=0; i<mq_table[mq].maxmsg-1; i++)

              mq_table[mq].mq_info[i].next = i+1;

            mq_table[mq].mq_info[mq_table[mq].maxmsg-1].next = -1;

            mq_table[mq].mq_first = 0;

            free_mq = mq_table[mq].next;

            kern_frestore(f);

            return mq;

          }

          else {

            errno = ENOSPC;

            kern_frestore(f);

            return -1;

          }

      }

    }

}

int mq_close(mqd_t mqdes)

{

    SYS_FLAGS f;

    f = kern_fsave();

    if (mqdes < 0 ||

        mqdes >= MQ_OPEN_MAX ||

        !(mq_table[mqdes].flags & MQ_USED) ) {

      errno = EBADF;

      kern_frestore(f);

      return -1;

    }

    kern_free(mq_table[mqdes].name, strlen(mq_table[mqdes].name)+1);

    kern_free(mq_table[mqdes].mq_data,

              mq_table[mqdes].maxmsg * mq_table[mqdes].msgsize);

    kern_free(mq_table[mqdes].mq_info,

              mq_table[mqdes].maxmsg * sizeof(struct mq_elem));

    mq_table[mqdes].flags = 0;

    mq_table[mqdes].next = free_mq;

    free_mq = mqdes;

    kern_frestore(f);

    return 0;

}

int mq_unlink(const char *name)

{

    int i;

    int found = 0;

    SYS_FLAGS f;

    f = kern_fsave();

    for (i = 0; i < MQ_OPEN_MAX; i++)

      if (mq_table[i].flags & MQ_USED) {

        if (strcmp((char*)name, mq_table[i].name) == 0) {

          found = 1;

        }

      }

    if (found) {

      kern_free(mq_table[i].name, strlen((char *)name)+1);

      kern_free(mq_table[i].mq_data,

                mq_table[i].maxmsg * mq_table[i].msgsize);

      kern_free(mq_table[i].mq_info,

                mq_table[i].maxmsg * sizeof(struct mq_elem));

      mq_table[i].flags = 0;

      mq_table[i].next = free_mq;

      free_mq = i;

      kern_frestore(f);

      return 0;

    } else {

      errno = ENOENT;

      kern_frestore(f);

      return -1;

    }

}

/* this function inserts a message in amessage queue mantaining the

   priority order */

static void insert_mq_entry(mqd_t mqdes, int newmsg)

{

    int prio; /* the priority of the message to insert */

    int p,q;  /* the messages... */

    p = NIL;

    q = mq_table[mqdes].start;

    prio = mq_table[mqdes].mq_info[ newmsg ].mq_prio;

    while ((q != NIL) && (prio <= mq_table[mqdes].mq_info[ q ].mq_prio)) {

        p = q;

        q = mq_table[mqdes].mq_info[ q ].next;

    }

    if (p != NIL)

      mq_table[mqdes].mq_info[ p ].next = newmsg;

    else

      mq_table[mqdes].start = newmsg;

    mq_table[mqdes].mq_info[ newmsg ].next = q;

}

/* this is the test that is done when a task is being killed

   and it is waiting on a sigwait */

static int mq_cancellation_point(PID i, void *arg)

{

    LEVEL l;

    if (proc_table[i].status == WAIT_MQSEND) {

      /* the task that have to be killed is waiting on a mq_send */

      /* we have to extract the task from the blocked queue... */

      iq_extract(i,&mq_table[mqproc_table[i].mqdes].blocked_send);

      /* and the task have to be reinserted into the ready queues, so it

         will fall into task_testcancel */

      l = proc_table[i].task_level;

      level_table[l]->public_unblock(l,i);

      return 1;

    }

    if (proc_table[i].status == WAIT_MQRECEIVE) {

      /* the task that have to be killed is waiting on a mq_send */

      /* we have to extract the task from the blocked queue... */

      iq_extract(i, &mq_table[mqproc_table[i].mqdes].blocked_rcv);

      /* and the task have to be reinserted into the ready queues, so it

         will fall into task_testcancel */

      l = proc_table[i].task_level;

      level_table[l]->public_unblock(l,i);

      return 1;

    }

    return 0;

}

int mq_interrupted_by_signal(PID i, void *arg)

{

    LEVEL l;

    if (proc_table[i].status == WAIT_MQSEND) {

      /* the task is waiting on a nanosleep and it is still receiving a

         signal... */

      mqproc_table[exec_shadow].intsig = 1;

      /* we have to extract the task from the blocked queue... */

      iq_extract(i, &mq_table[mqproc_table[i].mqdes].blocked_send);

      /* and the task have to be reinserted into the ready queues, so it

         will fall into task_testcancel */

      l = proc_table[i].task_level;

      level_table[l]->public_unblock(l,i);

      return 1;

    }

    if (proc_table[i].status == WAIT_MQRECEIVE) {

      /* the task is waiting on a nanosleep and it is still receiving a

         signal... */

      mqproc_table[exec_shadow].intsig = 1;

      /* we have to extract the task from the blocked queue... */

      iq_extract(i, &mq_table[mqproc_table[i].mqdes].blocked_rcv);

      /* and the task have to be reinserted into the ready queues, so it

         will fall into task_testcancel */

      l = proc_table[i].task_level;

      level_table[l]->public_unblock(l,i);

      return 1;

    }

    return 0;

}

int mq_send(mqd_t mqdes, const char *msg_ptr, size_t msg_len,

            unsigned int msg_prio)

{

  int newmsg;

  SYS_FLAGS f;

  task_testcancel();

  f = kern_fsave();

  /* first, if it is the first time that mq_receive or mq_send is called,

     register the cancellation point */

  if (mq_once) {

    mq_once = 0;

    register_cancellation_point(mq_cancellation_point, NULL);

    register_interruptable_point(mq_interrupted_by_signal, NULL);

  }

  if (mqdes < 0 ||

      mqdes >= MQ_OPEN_MAX ||

      !(mq_table[mqdes].flags & MQ_USED) ) {

    errno = EBADF;

    kern_frestore(f);

    return -1;

  }

  if (msg_len > mq_table[mqdes].msgsize) {

    errno = EMSGSIZE;

    kern_frestore(f);

    return -1;

  }

  if (msg_prio > MQ_PRIO_MAX) {

    errno = EINVAL;

    kern_frestore(f);

    return -1;

  }

  /* block the task if necessary */

  if (mq_table[mqdes].mq_first == -1) {

    /* the message queue is full!!! */

    if (mq_table[mqdes].flags & O_NONBLOCK) {

      errno = EAGAIN;

      kern_frestore(f);

      return -1;

    }

    else {

      LEVEL l;

      /* we block the task until:

         - a message is received, or

         - a signal is sent to the task, or

         - the task is killed               */

      mqproc_table[exec_shadow].intsig = 0;

      kern_epilogue_macro();

      l = proc_table[exec_shadow].task_level;

      level_table[l]->public_block(l,exec_shadow);

      /* we insert the task in the message queue */

      proc_table[exec_shadow].status = WAIT_MQSEND;

      iq_priority_insert(exec_shadow,&mq_table[mqdes].blocked_send);

      /* and finally we reschedule */

      exec = exec_shadow = -1;

      scheduler();

      ll_context_to(proc_table[exec_shadow].context);

      kern_deliver_pending_signals();

      /* mq_send is a cancellation point... */

      task_testcancel();

      if (mqproc_table[exec_shadow].intsig) {

        errno = EINTR;

        kern_frestore(f);

        return -1;

      }

    }

  }

  /* Now there is space to insert a new message */

  /* alloc a descriptor */

  newmsg = mq_table[mqdes].mq_first;

  mq_table[mqdes].mq_first = mq_table[mqdes].mq_info[newmsg].next;

  mq_table[mqdes].count++;

  /* fill the data */

  memcpy(mq_table[mqdes].mq_data + newmsg * mq_table[mqdes].msgsize,

         msg_ptr, msg_len);

  mq_table[mqdes].mq_info[ newmsg ].mq_prio = msg_prio;

  mq_table[mqdes].mq_info[ newmsg ].msglen  = msg_len;

  /* insert the data in an ordered way */

  insert_mq_entry(mqdes, newmsg);

//  kern_printf("Ûmq_des=%d, newmsg=%d, count=%dÛ",

//              mqdes, newmsg, mq_table[mqdes].count);

  if (mq_table[mqdes].count == 1) {

    /* the mq was empty */

    PID p;

    p = iq_getfirst(&mq_table[mqdes].blocked_rcv);

    if ( p != NIL) {

      /* The first blocked task has to be woken up */

      LEVEL l;

      proc_table[exec_shadow].context = ll_context_from();

      l = proc_table[p].task_level;

      level_table[l]->public_unblock(l,p);

      /* Preempt if necessary */

      scheduler();

      kern_context_load(proc_table[exec_shadow].context);

      return 0;

    }

    else if (mq_table[mqdes].flags & MQ_NOTIFICATION_PRESENT) {

      mq_table[mqdes].flags &= ~MQ_NOTIFICATION_PRESENT;

      // manage the notification...

      if (mq_table[mqdes].notification.sigev_notify == SIGEV_SIGNAL) {

          // there is no signal pending... post the signal!!!

          sigqueue_internal(0,

                            mq_table[mqdes].notification.sigev_signo,

                            mq_table[mqdes].notification.sigev_value,

                            SI_MESGQ);

      } else if (mq_table[mqdes].notification.sigev_notify == SIGEV_THREAD) {

        /* a new thread must be created; note that the pthread_create

           calls task_createn and task_activate; if task_activate is called

           into signal handlers and calls event_need_reschedule */

        pthread_t new_thread;

        if (mq_table[mqdes].notification.sigev_notify_attributes)

          pthread_create(&new_thread,

                         mq_table[mqdes].notification.sigev_notify_attributes,

                         (void *(*)(void *))mq_table[mqdes].notification.sigev_notify_function,

                         mq_table[mqdes].notification.sigev_value.sival_ptr);

        else {

          pthread_attr_t new_attr;

          // the task must be created detached

          pthread_attr_init(&new_attr);

          pthread_attr_setdetachstate(&new_attr, PTHREAD_CREATE_DETACHED);

          pthread_create(&new_thread,

                         &new_attr,

                         (void *(*)(void *))mq_table[mqdes].notification.sigev_notify_function,

                         &mq_table[mqdes].notification.sigev_value);

        }

      }

    }

  }

  kern_frestore(f);

  return 0;

}

ssize_t mq_receive(mqd_t mqdes, char *msg_ptr, size_t msg_len,

                   unsigned int *msg_prio)

{

  int msg;

  PID p;

  ssize_t returnvalue;

  SYS_FLAGS f;

  task_testcancel();

  f = kern_fsave();

  /* first, if it is the first time that mq_receive or mq_send is called,

     register the cancellation point */

  if (mq_once) {

    mq_once = 0;

    register_cancellation_point(mq_cancellation_point, NULL);

    register_interruptable_point(mq_interrupted_by_signal, NULL);

  }

  if (mqdes < 0 ||

      mqdes >= MQ_OPEN_MAX ||

      !(mq_table[mqdes].flags & MQ_USED) ) {

    errno = EBADF;

    kern_frestore(f);

    return -1;

  }

  if (msg_len > mq_table[mqdes].msgsize) {

    errno = EMSGSIZE;

    kern_frestore(f);

    return -1;

  }

  /* block the task if necessary */

  if (mq_table[mqdes].start == -1) {

    /* the message queue is empty!!! */

    if (mq_table[mqdes].flags & O_NONBLOCK) {

      errno = EAGAIN;

      kern_frestore(f);

      return -1;

    }

    else {

      LEVEL l;

      /* we block the task until:

         - a message arrives, or

         - a signal is sent to the task, or

         - the task is killed               */

      mqproc_table[exec_shadow].intsig = 0;

      kern_epilogue_macro();

      l = proc_table[exec_shadow].task_level;

      level_table[l]->public_block(l,exec_shadow);

      /* we insert the task into the message queue */

      proc_table[exec_shadow].status = WAIT_MQRECEIVE;

      iq_priority_insert(exec_shadow,&mq_table[mqdes].blocked_rcv);

      /* and finally we reschedule */

      exec = exec_shadow = -1;

      scheduler();

      ll_context_to(proc_table[exec_shadow].context);

      kern_deliver_pending_signals();

      /* mq_receive is a cancellation point... */

      task_testcancel();

      if (mqproc_table[exec_shadow].intsig) {

        errno = EINTR;

        kern_frestore(f);

        return -1;

      }

    }

  }

  /* Now there is at least one message...

     copy it to the destination, ... */

  msg = mq_table[mqdes].start;

  memcpy(msg_ptr,

         mq_table[mqdes].mq_data + msg * mq_table[mqdes].msgsize,

         mq_table[mqdes].msgsize);

  /* ...update the first messagee and the counters, ... */

  mq_table[mqdes].count++;

  mq_table[mqdes].start = mq_table[mqdes].mq_info[ msg ].next;

  /* and finally the free message queue */

  mq_table[mqdes].mq_info[ msg ].next = mq_table[mqdes].mq_first;

  mq_table[mqdes].mq_first = msg;

  /* return the priority if required */

  if (msg_prio) {

    *msg_prio = mq_table[mqdes].mq_info[ msg ].mq_prio;

  }

  /* set the returnvalue */

  returnvalue = mq_table[mqdes].mq_info[ msg ].msglen;

  /* if the mq was full, there may be a task into blocked-send queue */

  p = iq_getfirst(&mq_table[mqdes].blocked_send);

  if ( p != NIL) {

    /* The first blocked task on send has to be woken up */

    LEVEL l;

    proc_table[exec_shadow].context = ll_context_from();

    l = proc_table[p].task_level;

    level_table[l]->public_unblock(l,p);

    /* Preempt if necessary */

    scheduler();

    kern_context_load(proc_table[exec_shadow].context);

    return returnvalue;

  }

  kern_frestore(f);

  return returnvalue;

}

int mq_notify(mqd_t mqdes, const struct sigevent *notification)

{

  SYS_FLAGS f;

  f = kern_fsave();

  if (mqdes < 0 ||

      mqdes >= MQ_OPEN_MAX ||

      !(mq_table[mqdes].flags & MQ_USED) ) {

    errno = EBADF;

    kern_frestore(f);

    return -1;

  }

  if (mq_table[mqdes].flags & MQ_NOTIFICATION_PRESENT) {

    if (!notification) {

      mq_table[mqdes].flags &= ~MQ_NOTIFICATION_PRESENT;

      kern_frestore(f);

      return 0;

    }

    else {

      errno = EBUSY;

      kern_frestore(f);

      return -1;

    }

  }

  mq_table[mqdes].flags |= MQ_NOTIFICATION_PRESENT;

  memcpy(&mq_table[mqdes].notification, notification,sizeof(struct sigevent));

  kern_frestore(f);

  return 0;

}

int mq_setattr(mqd_t mqdes, const struct mq_attr *mqstat,

               struct mq_attr *omqstat)

{

  SYS_FLAGS f;

  f = kern_fsave();

  if (mqdes < 0 ||

      mqdes >= MQ_OPEN_MAX ||

      !(mq_table[mqdes].flags & MQ_USED) ) {

    errno = EBADF;

    kern_frestore(f);

    return -1;

  }

  if (omqstat) {

    omqstat->mq_flags   = mq_table[mqdes].flags & O_NONBLOCK;

    omqstat->mq_maxmsg  = mq_table[mqdes].maxmsg;

    omqstat->mq_msgsize = mq_table[mqdes].msgsize;

    omqstat->mq_curmsgs = mq_table[mqdes].count;

  }

  mq_table[mqdes].flags = (mq_table[mqdes].flags & ~O_NONBLOCK) |

                          (mqstat->mq_flags & O_NONBLOCK);

  kern_frestore(f);

  return 0;

}

int mq_getattr(mqd_t mqdes, struct mq_attr *mqstat)

{

  SYS_FLAGS f;

  f = kern_fsave();

  if (mqdes < 0 ||

      mqdes >= MQ_OPEN_MAX ||

      !(mq_table[mqdes].flags & MQ_USED) ) {

    errno = EBADF;

    kern_frestore(f);

    return -1;

  }

  mqstat->mq_flags   = mq_table[mqdes].flags & O_NONBLOCK;

  mqstat->mq_maxmsg  = mq_table[mqdes].maxmsg;

  mqstat->mq_msgsize = mq_table[mqdes].msgsize;

  mqstat->mq_curmsgs = mq_table[mqdes].count;

  kern_frestore(f);

  return 0;

}