lib/libc/termios/tcgetpgrp.c

   1 /*      $NetBSD: tcgetpgrp.c,v 1.10 2012/06/25 22:32:46 abs Exp $       */
   2
   3 /*-
   4  * Copyright (c) 1989, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 #if 0
  35 static char sccsid[] = "@(#)termios.c   8.2 (Berkeley) 2/21/94";
  36 #else
  37 __RCSID("$NetBSD: tcgetpgrp.c,v 1.10 2012/06/25 22:32:46 abs Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include <sys/types.h>
  43 #include <sys/ioctl.h>
  44
  45 #include <assert.h>
  46 #include <errno.h>
  47 #include <termios.h>
  48 #include <unistd.h>
  49
  50 #ifdef __weak_alias
  51 __weak_alias(tcgetpgrp,_tcgetpgrp)
  52 #endif
  53
  54 pid_t
  55 tcgetpgrp(int fd)
  56 {
  57         int s;
  58
  59         _DIAGASSERT(fd != -1);
  60
  61         if (ioctl(fd, TIOCGPGRP, &s) < 0)
  62                 return ((pid_t)-1);
  63
  64         if (s == (pid_t)-1)
  65                 /* SVID requires a number > 1 that isn't a valid PGID... */
  66                 s = (uint)(pid_t)~0u >> 1;
  67         return ((pid_t)s);
  68 }