ftok.c revision 1.10 
1/*	$NetBSD: ftok.c,v 1.10 2004/09/15 19:45:17 hubertf 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29#if defined(LIBC_SCCS) && !defined(lint)
30__RCSID("$NetBSD: ftok.c,v 1.10 2004/09/15 19:45:17 hubertf Exp $");
31#endif /* LIBC_SCCS and not lint */
32
33#include "namespace.h"
34#include <sys/types.h>
35#include <sys/stat.h>
36#include <sys/ipc.h>
37
38#include <assert.h>
39#include <errno.h>
40
41#ifdef __weak_alias
42__weak_alias(ftok,_ftok)
43#endif
44
45key_t
46ftok(path, id)
47	const char *path;
48	int id;
49{
50	struct stat st;
51
52	_DIAGASSERT(path != NULL);
53
54	if (stat(path, &st) < 0)
55		return (key_t)-1;
56
57	return (key_t)
58	    (id << 24 | (st.st_dev & 0xff) << 16 | (st.st_ino & 0xffff));
59}
60