7ffe927935
Document that only the 8 least significant bits are used in the key generation and that the return value is (key_t)-1 [this is to fix K&R vs. ansi compilation and lint warnings]
57 lines
2.0 KiB
C
57 lines
2.0 KiB
C
/* $NetBSD: ftok.c,v 1.6 1998/11/12 16:15:17 christos Exp $ */
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/*
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* Copyright (c) 1994 SigmaSoft, Th. Lockert <tholo@sigmasoft.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: ftok.c,v 1.6 1998/11/12 16:15:17 christos Exp $");
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#endif /* LIBC_SCCS and not lint */
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#include "namespace.h"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/ipc.h>
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#ifdef __weak_alias
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__weak_alias(ftok,_ftok);
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#endif
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key_t
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ftok(path, id)
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const char *path;
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int id;
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{
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struct stat st;
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if (stat(path, &st) < 0)
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return (key_t)-1;
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return (key_t)
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(id << 24 | (st.st_dev & 0xff) << 16 | (st.st_ino & 0xffff));
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}
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