glibc/sysdeps/mach/hurd/getpgid.c

/* Copyright (C) 1991-2021 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
   <https://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <unistd.h>
#include <hurd.h>
#include <hurd/port.h>

/* Get the process group ID of process PID.  */
int
__getpgid (pid_t pid)
{
  error_t err;
  pid_t pgrp;

  if (pid == 0)
    {
      /* Assume atomic word fetch and store, so don't lock _hurd_pid_lock.  */
      pgrp = _hurd_pgrp;
      err = 0;
    }
  else
    err = __USEPORT (PROC, __proc_getpgrp (port, pid, &pgrp));

  return err ? __hurd_fail (err) : pgrp;
}
libc_hidden_def (__getpgid)
weak_alias (__getpgid, getpgid)