/* Create subprocess.

   Copyright (C) 2019 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <stdio.h>

#include <signal.h>

#include <time.h>

#include <sys/wait.h>

#include <stdbool.h>

#include <support/xspawn.h>

#include <support/check.h>

#include <support/xunistd.h>

#include <support/subprocess.h>

static struct support_subprocess

support_suprocess_init (void)

{

  struct support_subprocess result;

  xpipe (result.stdout_pipe);

  TEST_VERIFY (result.stdout_pipe[0] > STDERR_FILENO);

  TEST_VERIFY (result.stdout_pipe[1] > STDERR_FILENO);

  xpipe (result.stderr_pipe);

  TEST_VERIFY (result.stderr_pipe[0] > STDERR_FILENO);

  TEST_VERIFY (result.stderr_pipe[1] > STDERR_FILENO);

  TEST_VERIFY (fflush (stdout) == 0);

  TEST_VERIFY (fflush (stderr) == 0);

  return result;

}

struct support_subprocess

support_subprocess (void (*callback) (void *), void *closure)

{

  struct support_subprocess result = support_suprocess_init ();

  result.pid = xfork ();

  if (result.pid == 0)

    {

      xclose (result.stdout_pipe[0]);

      xclose (result.stderr_pipe[0]);

      xdup2 (result.stdout_pipe[1], STDOUT_FILENO);

      xdup2 (result.stderr_pipe[1], STDERR_FILENO);

      xclose (result.stdout_pipe[1]);

      xclose (result.stderr_pipe[1]);

      callback (closure);

     _exit (0);

    }

  xclose (result.stdout_pipe[1]);

  xclose (result.stderr_pipe[1]);

  return result;

}

struct support_subprocess

support_subprogram (const char *file, char *const argv[])

{

  struct support_subprocess result = support_suprocess_init ();

  posix_spawn_file_actions_t fa;

  /* posix_spawn_file_actions_init does not fail.  */

  posix_spawn_file_actions_init (&fa);

  xposix_spawn_file_actions_addclose (&fa, result.stdout_pipe[0]);

  xposix_spawn_file_actions_addclose (&fa, result.stderr_pipe[0]);

  xposix_spawn_file_actions_adddup2 (&fa, result.stdout_pipe[1], STDOUT_FILENO);

  xposix_spawn_file_actions_adddup2 (&fa, result.stderr_pipe[1], STDERR_FILENO);

  xposix_spawn_file_actions_addclose (&fa, result.stdout_pipe[1]);

  xposix_spawn_file_actions_addclose (&fa, result.stderr_pipe[1]);

  result.pid = xposix_spawn (file, &fa, NULL, argv, NULL);

  xclose (result.stdout_pipe[1]);

  xclose (result.stderr_pipe[1]);

  return result;

}

int

support_process_wait (struct support_subprocess *proc)

{

  xclose (proc->stdout_pipe[0]);

  xclose (proc->stderr_pipe[0]);

  int status;

  xwaitpid (proc->pid, &status, 0);

  return status;

}

static bool

support_process_kill (int pid, int signo, int *status)

{

  /* Kill the whole process group.  */

  kill (-pid, signo);

  /* In case setpgid failed in the child, kill it individually too.  */

  kill (pid, signo);

  /* Wait for it to terminate.  */

  pid_t killed;

  for (int i = 0; i < 5; ++i)

    {

      int status;

      killed = xwaitpid (pid, &status, WNOHANG|WUNTRACED);

      if (killed != 0)

        break;

      /* Delay, give the system time to process the kill.  If the

         nanosleep() call return prematurely, all the better.  We

         won't restart it since this probably means the child process

         finally died.  */

      nanosleep (&((struct timespec) { 0, 100000000 }), NULL);

    }

  if (killed != 0 && killed != pid)

    return false;

  return true;

}

int

support_process_terminate (struct support_subprocess *proc)

{

  xclose (proc->stdout_pipe[0]);

  xclose (proc->stderr_pipe[0]);

  int status;

  pid_t killed = xwaitpid (proc->pid, &status, WNOHANG|WUNTRACED);

  if (killed != 0 && killed == proc->pid)

    return status;

  /* Subprocess is still running, terminate it.  */

  if (!support_process_kill (proc->pid, SIGTERM, &status) )

    support_process_kill (proc->pid, SIGKILL, &status);

  return status;

}