71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
/*
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* magic.c - PPP Magic Number routines.
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*
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* Copyright (c) 1989 Carnegie Mellon University.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by Carnegie Mellon University. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#ifndef lint
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static char rcsid[] = "$Id: magic.c,v 1.1 1993/11/11 03:54:25 paulus Exp $";
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#endif
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/time.h>
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#include "magic.h"
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static u_long next; /* Next value to return */
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extern u_long gethostid __ARGS((void));
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extern long random __ARGS((void));
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extern void srandom __ARGS((int));
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/*
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* magic_init - Initialize the magic number generator.
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*
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* Computes first magic number and seed for random number generator.
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* Attempts to compute a random number seed which will not repeat.
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* The current method uses the current hostid and current time.
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*/
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void magic_init()
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{
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struct timeval tv;
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next = gethostid();
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if (gettimeofday(&tv, NULL)) {
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perror("gettimeofday");
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exit(1);
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}
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next ^= (u_long) tv.tv_sec ^ (u_long) tv.tv_usec;
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srandom((int) next);
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}
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/*
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* magic - Returns the next magic number.
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*/
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u_long magic()
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{
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u_long m;
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m = next;
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next = (u_long) random();
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return (m);
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}
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