/* Copyright (C) 1993-2018 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 <errno.h>

#include <unistd.h>

#include <hurd.h>

#include <hurd/port.h>

#include <hurd/fd.h>

#include <hurd/ioctl.h>

#include <lowlevellock.h>

/* Create a new session with the calling process as its leader.

   The process group IDs of the session and the calling process

   are set to the process ID of the calling process, which is returned.  */

pid_t

__setsid (void)

{

  error_t err;

  unsigned int stamp;

  HURD_CRITICAL_BEGIN;

  __mutex_lock (&_hurd_dtable_lock);

  stamp = _hurd_pids_changed_stamp; /* Atomic fetch.  */

  /* Tell the proc server we want to start a new session.  */

  err = __USEPORT (PROC, __proc_setsid (port));

  if (err)

    __mutex_unlock (&_hurd_dtable_lock);

  else

    {

      /* Punt our current ctty, and update the dtable accordingly.  We hold

	 the dtable lock from before the proc_setsid call through clearing

	 the cttyid port and processing the dtable, so that we can be sure

	 that it's all done by the time the signal thread processes the

	 pgrp change notification.  */

      _hurd_locked_install_cttyid (MACH_PORT_NULL);

      /* Synchronize with the signal thread to make sure we have received

	 and processed proc_newids before returning to the user.

	 This is necessary to ensure that _hurd_pgrp (and thus the value

	 returned by `getpgrp ()' in other threads) has been updated before

	 we return.  */

      while (_hurd_pids_changed_stamp == stamp)

        lll_wait (&_hurd_pids_changed_stamp, stamp, 0);

    }

  HURD_CRITICAL_END;

  return err ? __hurd_fail (err) : _hurd_pgrp;

}

weak_alias (__setsid, setsid)