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