source: kBuild/vendor/grep/current/gnulib-tests/test-sigprocmask.c

/* Test of sigprocmask.
   Copyright (C) 2011-2021 Free Software Foundation, Inc.

   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 3 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, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <bruno@clisp.org>, 2011.  */

#include <config.h>

#include <signal.h>

#include "signature.h"
SIGNATURE_CHECK (sigprocmask, int, (int, const sigset_t *, sigset_t *));

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "macros.h"

#if !(defined _WIN32 && !defined __CYGWIN__)

static volatile int sigint_occurred;

static void
sigint_handler (int sig)
{
  sigint_occurred++;
}

int
main (int argc, char *argv[])
{
  sigset_t set;
  pid_t pid = getpid ();
  char command[80];

  if (sizeof (int) < sizeof pid && 0x7fffffff < pid)
    {
      fputs ("Skipping test: pid too large\n", stderr);
      return 77;
    }

  signal (SIGINT, sigint_handler);

  sigemptyset (&set);
  sigaddset (&set, SIGINT);

  /* Check error handling.  */
  ASSERT (sigprocmask (1729, &set, NULL) == -1);
  ASSERT (errno == EINVAL);

  /* Block SIGINT.  */
  ASSERT (sigprocmask (SIG_BLOCK, &set, NULL) == 0);

  /* Request a SIGINT signal from outside.  */
  sprintf (command, "sh -c 'sleep 1; kill -%d %d' &", SIGINT, (int) pid);
  ASSERT (system (command) == 0);

  /* Wait.  */
  sleep (2);

  /* The signal should not have arrived yet, because it is blocked.  */
  ASSERT (sigint_occurred == 0);

  /* Unblock SIGINT.  */
  ASSERT (sigprocmask (SIG_UNBLOCK, &set, NULL) == 0);

  /* The signal should have arrived now, because POSIX says
       "If there are any pending unblocked signals after the call to
        sigprocmask(), at least one of those signals shall be delivered
        before the call to sigprocmask() returns."  */
  ASSERT (sigint_occurred == 1);

  return 0;
}

#else

/* On native Windows, getpid() values and the arguments that are passed to
   the (Cygwin?) 'kill' program are not necessarily related.  */

int
main ()
{
  fputs ("Skipping test: native Windows platform\n", stderr);
  return 77;
}

#endif