bin/tools/genrandom.c

	genrandom.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 2000-2005, 2007, 2009, 2010, 2012, 2014, 2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* $Id: genrandom.c,v 1.7 2010/05/17 23:51:04 tbox Exp $ */

/*! \file */
#include <config.h>

#include <isc/commandline.h>
#include <isc/print.h>
#include <isc/stdlib.h>
#include <isc/util.h>

#include <stdio.h>
#include <string.h>

const char *program = "genrandom";

ISC_PLATFORM_NORETURN_PRE static void
usage(void) ISC_PLATFORM_NORETURN_POST;

static void
usage(void) {
    fprintf(stderr, "usage: %s [-n 2..9] k file\n", program);
    exit(1);
}

static void
generate(char *filename, unsigned int bytes) {
    FILE *fp;

    fp = fopen(filename, "w");
    if (fp == NULL) {
        printf("failed to open %s\n", filename);
        exit(1);
    }

    while (bytes > 0) {
#ifndef HAVE_ARC4RANDOM
        unsigned short int x = (rand() & 0xFFFF);
#else
        unsigned short int x = (arc4random() & 0xFFFF);
#endif
        unsigned char c = x & 0xFF;
        if (putc(c, fp) == EOF) {
            printf("error writing to %s\n", filename);
            exit(1);
        }
        c = x >> 8;
        if (putc(c, fp) == EOF) {
            printf("error writing to %s\n", filename);
            exit(1);
        }
        bytes -= 2;
    }
    fclose(fp);
}

int
main(int argc, char **argv) {
    unsigned int bytes;
    unsigned int k;
    char *endp;
    int c, i, n = 1;
    size_t len;
    char *name;

    isc_commandline_errprint = ISC_FALSE;

    while ((c = isc_commandline_parse(argc, argv, "hn:")) != EOF) {
        switch (c) {
        case 'n':
            n = strtol(isc_commandline_argument, &endp, 10);
            if ((*endp != 0) || (n <= 1) || (n > 9))
                usage();
            break;

        case '?':
            if (isc_commandline_option != '?')
                fprintf(stderr, "%s: invalid argument -%c\n",
                    program, isc_commandline_option);
            /* FALLTHROUGH */
        case 'h':
            usage();

        default:
            fprintf(stderr, "%s: unhandled option -%c\n",
                program, isc_commandline_option);
            exit(1);
        }
    }

    if (isc_commandline_index + 2 != argc)
        usage();

    k = strtoul(argv[isc_commandline_index++], &endp, 10);
    if (*endp != 0)
        usage();
    bytes = k << 10;

#ifndef HAVE_ARC4RANDOM
    srand(0x12345678);
#endif
    if (n == 1) {
        generate(argv[isc_commandline_index], bytes);
        return (0);
    }

    len = strlen(argv[isc_commandline_index]);
    INSIST((len + 2) > len);
    len += 2;
    name = (char *) malloc(len);
    if (name == NULL) {
        perror("malloc");
        exit(1);
    }

    for (i = 1; i <= n; i++) {
        snprintf(name, len, "%s%d", argv[isc_commandline_index], i);
        generate(name, bytes);
    }
    free(name);

    return (0);
}