nuttx/sched/signal/sig_procmask.c

/****************************************************************************
 * sched/signal/sig_procmask.c
 *
 *   Copyright (C) 2007-2009, 2014, 2016-2017 Gregory Nutt. All rights
 *     reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * 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 NuttX 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 <nuttx/config.h>

#include <unistd.h>
#include <signal.h>
#include <time.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>

#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/wdog.h>
#include <nuttx/kmalloc.h>
#include <nuttx/signal.h>

#include "sched/sched.h"
#include "signal/signal.h"

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

/****************************************************************************
 * Name: nxsig_procmask
 *
 * 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
 *   nxsig_procmask(), those signals will be delivered before
 *    nxsig_procmask() returns.
 *
 *   If nxsig_procmask() fails, the signal mask of the process is not changed
 *   by this function call.
 *
 *   This is an internal OS interface.  It is functionally equivalent to
 *   sigprocmask() except that it does not modify the errno value.
 *
 * 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:
 *   This is an internal OS interface and should not be used by applications.
 *   It follows the NuttX internal error return policy:  Zero (OK) is
 *   returned on success.  A negated errno value is returned on failure.
 *
 *     EINVAL - The 'how' argument is invalid.
 *
 ****************************************************************************/

int nxsig_procmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
{
  FAR struct tcb_s *rtcb = this_task();
  sigset_t   oldsigprocmask;
  irqstate_t flags;
  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 != NULL)
    {
      /* Some of these operations are non-atomic.  We need to protect
       * ourselves from attempts to process signals from interrupts
       */

      flags = enter_critical_section();

      /* 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 = -EINVAL;
            break;
        }

      leave_critical_section(flags);

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

      nxsig_unmask_pendingsignal();
    }

  sched_unlock();
  return ret;
}

/****************************************************************************
 * Name: 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:
 *   This function will return 0 (OK) on success or -1 (ERROR) if how is
 *   invalid.  In the latter case, the errno variable will be set to EINVAL.
 *
 ****************************************************************************/

int sigprocmask(int how, FAR const sigset_t *set, FAR sigset_t *oset)
{
  int ret;

  /* Let nxsig_procmask do all of the work */

  ret = nxsig_procmask(how, set, oset);
  if (ret < 0)
    {
      set_errno(-ret);
      ret = ERROR;
    }

  return ret;
}