/* 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 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, 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> #include <unistd.h> /* Return the session ID of FD. */ pid_t tcgetsid (fd) 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; }