Subversion Repositories or1k

/* Copyright (C) 1997, 1999 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 Library General Public License as

   published by the Free Software Foundation; either version 2 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

   Library General Public License for more details.

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

   License along with the GNU C Library; see the file COPYING.LIB.  If not,

   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,

   Boston, MA 02111-1307, USA.  */

#include <errno.h>

#include <termios.h>

#include <sys/ioctl.h>

#include <sys/types.h>

#define __USE_XOPEN_EXTENDED

#include <unistd.h>

/* Return the session ID of FD.  */

pid_t tcgetsid (int fd)

{

    pid_t pgrp;

    pid_t sid;

#ifdef TIOCGSID

    static int tiocgsid_does_not_work;

    if (! tiocgsid_does_not_work)

    {

        int serrno = errno;

        int sid;

        if (ioctl (fd, TIOCGSID, &sid) < 0)

        {

            if (errno == EINVAL)

            {

                tiocgsid_does_not_work = 1;

                __set_errno(serrno);

            }

            else

                return (pid_t) -1;

        }

        else

            return (pid_t) sid;

    }

#endif

    pgrp = tcgetpgrp (fd);

    if (pgrp == -1)

        return (pid_t) -1;

    sid = getsid (pgrp);

    if (sid == -1 && errno == ESRCH)

        __set_errno(ENOTTY);

    return sid;

}