nuttx/sched/sig_mqnotempty.c

/************************************************************
 * sig_mqnotempty.c
 *
 *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name Gregory Nutt nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ************************************************************/

/************************************************************
 * Included Files
 ************************************************************/

#include <sys/types.h>
#include <signal.h>
#include <sched.h>
#include <debug.h>
#include "os_internal.h"
#include "sig_internal.h"

/************************************************************
 * Definitions
 ************************************************************/

/************************************************************
 * Private Type Declarations
 ************************************************************/

/************************************************************
 * Global Variables
 ************************************************************/

/************************************************************
 * Private Variables
 ************************************************************/

/************************************************************
 * Private Functionss
 ************************************************************/

/************************************************************
 * Public Functions
 ************************************************************/

/************************************************************
 * Function: sig_mqnotempty
 *
 * Description:
 *   This function is equivalent to sigqueue(), but supports
 *   the messaging system's requirement to signal a task when
 *   a message queue becomes non-empty.  It is identical to
 *   sigqueue(), except that it sets the si_code field in
 *   the siginfo structure to SI_MESGQ rather than SI_QUEUE.
 *
 ************************************************************/

int sig_mqnotempty (int pid, int signo, const union sigval value)
{
  _TCB     *stcb;
  siginfo_t info;
  int       ret = ERROR;

  sched_lock();

  /* Get the TCB of the receiving task */

  stcb = sched_gettcb(pid);
  dbg("sig_mqnotempty: TCB=0x%08x signo=%d value=%d\n",
      stcb, signo, value.sival_int);

  /* Create the siginfo structure */

  info.si_signo = signo;
  info.si_code  = SI_MESGQ;
  info.si_value = value;

  /* Verify that we can perform the signalling operation */

  if ((stcb) && (GOOD_SIGNO(signo)))
   {
     /* Process the receipt of the signal */
     ret = sig_received(stcb, &info);
   }

  sched_unlock();
  return ret;
}