nuttx/sched/sig_procmask.c

/************************************************************
 * sig_procmask.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 <unistd.h>
#include <signal.h>
#include <time.h>
#include <wdog.h>
#include <assert.h>
#include <debug.h>
#include <sched.h>
#include <nuttx/kmalloc.h>
#include <nuttx/arch.h>
#include <nuttx/os_external.h>
#include "os_internal.h"
#include "sig_internal.h"

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

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

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

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

/************************************************************
 * Private Function Prototypes
 ************************************************************/

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

/************************************************************
 * Function: sigprocmask
 *
 * Description:
 *   This function allows the calling process to examine
 *   and/or change its signal mask.  If the set is not NULL,
 *   then it points to a set of signals to be used to change
 *   the currently blocked set.  The value of how indicates
 *   the manner in which the set is changed.
 *
 *   If there any pending unblocked signals after the call
 *   to sigprocmask(), those signals will be delivered
 *   before sigprocmask() returns.
 *
 *   If sigprocmask() fails, the signal mask of the process
 *   is not changed by this function call.
 *
 * Parameters:
 *   how - How the signal mast will be changed:
 *         SIG_BLOCK   - The resulting set is the union of
 *                       the current set and the signal set
 *                       pointed to by set.
 *         SIG_UNBLOCK - The resulting set is the intersection
 *                       of the current set and the complement
 *                       of the signal set pointed to by _set.
 *         SIG_SETMASK - The resulting set is the signal set
 *                       pointed to by set.
 *   set - Location of the new signal mask
 *   oset - Location to store the old signal mask
 *
 * Return Value:
 *   0 (OK), or -1 (ERROR) if how is invalid.
 *
 * Assumptions:
 *
 ************************************************************/

int sigprocmask(int how, const sigset_t *set, sigset_t *oset)
{
  FAR _TCB  *rtcb = (FAR _TCB*)g_readytorun.head;
  sigset_t   oldsigprocmask;
  irqstate_t saved_state;
  int        ret = OK;

  sched_lock();

  /* Return the old signal mask if requested */

  oldsigprocmask = rtcb->sigprocmask;
  if (oset)
    {
      *oset = oldsigprocmask;
    }

  /* Modify the current signal mask if so requested */

  if (set)
    {
      /* Some of these operations are non-atomic.  We need to protect
       * ourselves from attempts to process signals from interrupts
       */

      saved_state = irqsave();

      /* Okay, determine what we are supposed to do */

      switch (how)
        {
          /* The resulting set is the union of the current set and the
           * signal set pointed to by set.
           */

          case SIG_BLOCK:
            rtcb->sigprocmask |= *set;
            break;

          /* The resulting set is the intersection of the current set and
           * the complement of the signal set pointed to by _set.
           */

          case SIG_UNBLOCK:
            rtcb->sigprocmask &= ~(*set);
            break;

          /* The resulting set is the signal set pointed to by set. */

          case SIG_SETMASK:
            rtcb->sigprocmask = *set;
            break;

          default: 
            ret = ERROR;
            break;
        }
      irqrestore(saved_state);

      /* Now, process any pending signals that were just unmasked */

      sig_unmaskpendingsignal();
    }

   sched_unlock();
   return ret;
}