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/*++
/* NAME
/* rand_sleep 3
/* SUMMARY
/* sleep for randomized interval
/* SYNOPSIS
/* #include <iostuff.h>
/*
/* void rand_sleep(delay, variation)
/* unsigned delay;
/* unsigned variation;
/* DESCRIPTION
/* rand_sleep() blocks the current process for an amount of time
/* pseudo-randomly chosen from the interval (delay +- variation/2).
/*
/* Arguments:
/* .IP delay
/* Time to sleep in microseconds.
/* .IP variation
/* Variation in microseconds; must not be larger than delay.
/* DIAGNOSTICS
/* Panic: interface violation. All system call errors are fatal.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
/* Utility library. */
#include <msg.h>
#include <myrand.h>
#include <iostuff.h>
/* rand_sleep - block for random time */
void rand_sleep(unsigned delay, unsigned variation)
{
const char *myname = "rand_sleep";
unsigned usec;
/*
* Sanity checks.
*/
if (delay == 0)
msg_panic("%s: bad delay %d", myname, delay);
if (variation > delay)
msg_panic("%s: bad variation %d", myname, variation);
/*
* Use the semi-crappy random number generator.
*/
usec = (delay - variation / 2) + variation * (double) myrand() / RAND_MAX;
doze(usec);
}
#ifdef TEST
#include <msg_vstream.h>
int main(int argc, char **argv)
{
int delay;
int variation;
msg_vstream_init(argv[0], VSTREAM_ERR);
if (argc != 3)
msg_fatal("usage: %s delay variation", argv[0]);
if ((delay = atoi(argv[1])) <= 0)
msg_fatal("bad delay: %s", argv[1]);
if ((variation = atoi(argv[2])) < 0)
msg_fatal("bad variation: %s", argv[2]);
rand_sleep(delay * 1000000, variation * 1000000);
exit(0);
}
#endif
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