ftok.c revision 1.8 
1/*	$NetBSD: ftok.c,v 1.8 1999/09/20 04:38:59 lukem Exp $	*/
2
3/*
4 * Copyright (c) 1994 SigmaSoft, Th. Lockert <tholo@sigmasoft.com>
5 * 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. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31#if defined(LIBC_SCCS) && !defined(lint)
32__RCSID("$NetBSD: ftok.c,v 1.8 1999/09/20 04:38:59 lukem Exp $");
33#endif /* LIBC_SCCS and not lint */
34
35#include "namespace.h"
36#include <sys/types.h>
37#include <sys/stat.h>
38#include <sys/ipc.h>
39
40#include <assert.h>
41#include <errno.h>
42
43#ifdef __weak_alias
44__weak_alias(ftok,_ftok);
45#endif
46
47key_t
48ftok(path, id)
49	const char *path;
50	int id;
51{
52	struct stat st;
53
54	_DIAGASSERT(path != NULL);
55
56	if (stat(path, &st) < 0)
57		return (key_t)-1;
58
59	return (key_t)
60	    (id << 24 | (st.st_dev & 0xff) << 16 | (st.st_ino & 0xffff));
61}
62