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/*
* random bit generation for scripts, control files, etc.
* Copyright (C) 1998, 1999, 2000 Henry Spencer.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* RCSID $Id: ranbits.c,v 1.1 2004/03/15 20:35:30 as Exp $
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <limits.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <freeswan.h>
#ifndef DEVICE
#define DEVICE "/dev/random"
#endif
#ifndef QDEVICE
#define QDEVICE "/dev/urandom"
#endif
#ifndef MAXBITS
#define MAXBITS 20000
#endif
char usage[] = "Usage: ranbits [--quick] [--continuous] [--bytes] nbits";
struct option opts[] = {
{"quick", 0, NULL, 'q',},
{"continuous", 0, NULL, 'c',},
{"bytes", 0, NULL, 'b',},
{"help", 0, NULL, 'h',},
{"version", 0, NULL, 'v',},
{0, 0, NULL, 0,}
};
int quick = 0; /* quick and dirty? */
char format = 'h'; /* datatot() format code */
int isbytes = 0; /* byte count rather than bits? */
char me[] = "ipsec ranbits"; /* for messages */
char buf[MAXBITS/CHAR_BIT];
char outbuf[3*sizeof(buf)];
int main(int argc, char *argv[])
{
int opt;
extern int optind;
int errflg = 0;
int nbits;
size_t nbytes;
char *devname;
int dev;
size_t ndone;
size_t nneeded;
ssize_t got;
while ((opt = getopt_long(argc, argv, "", opts, NULL)) != EOF)
switch (opt) {
case 'q': /* quick and dirty randomness */
quick = 1;
break;
case 'c': /* continuous hex, no underscores */
format = 'x';
break;
case 'b': /* byte count, not bit count */
isbytes = 1;
break;
case 'h': /* help */
printf("%s\n", usage);
exit(0);
break;
case 'v': /* version */
printf("%s %s\n", me, ipsec_version_code());
exit(0);
break;
case '?':
default:
errflg = 1;
break;
}
if (errflg || optind != argc-1) {
fprintf(stderr, "%s\n", usage);
exit(2);
}
nbits = atoi(argv[optind]);
if (isbytes)
nbits *= CHAR_BIT;
if (nbits <= 0) {
fprintf(stderr, "%s: invalid bit count (%d)\n", me, nbits);
exit(1);
}
if (nbits > MAXBITS) {
fprintf(stderr, "%s: overlarge bit count (max %d)\n", me,
MAXBITS);
exit(1);
}
nbytes = (size_t)(nbits + CHAR_BIT - 1) / CHAR_BIT;
devname = (quick) ? QDEVICE : DEVICE;
dev = open(devname, 0);
if (dev < 0) {
fprintf(stderr, "%s: could not open %s (%s)\n", me,
devname, strerror(errno));
exit(1);
}
ndone = 0;
while (ndone < nbytes) {
got = read(dev, buf + ndone, nbytes - ndone);
if (got < 0) {
fprintf(stderr, "%s: read error on %s (%s)\n", me,
devname, strerror(errno));
exit(1);
}
if (got == 0) {
fprintf(stderr, "%s: eof on %s!?!\n", me, devname);
exit(1);
}
ndone += got;
}
nneeded = datatot(buf, nbytes, format, outbuf, sizeof(outbuf));
if (nneeded > sizeof(outbuf)) {
fprintf(stderr, "%s: buffer overflow (need %ld bytes)?!?\n",
me, (long)nneeded);
exit(1);
}
printf("%s\n", outbuf);
exit(0);
}
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