/* * Copyright (c) 2016 Red Hat Inc. * * 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. * * This program is distributed in the hope that it would 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. * * You should have received a copy of the GNU General Public License * along with this program; if not, write the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * * Author: Chunyu Hu <chuhu@redhat.com> * */ #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <sys/time.h> static void print_help(void) { printf("Usage: tst_random <value1> [value2]\n"); printf(" Generated random will be between value1 and value2.\n"); printf(" If only value1 is specified, value2 will treated as 0.\n"); } static int get_seed(void) { struct timeval tv; gettimeofday(&tv, NULL); return tv.tv_usec; } static long rand_range(long min, long max) { return random() % (max - min + 1) + min; } int main(int argc, char *argv[]) { int opt; long min = 0, max = 0; long rval = 0; char *end; while ((opt = getopt(argc, argv, ":h")) != -1) { switch (opt) { case 'h': print_help(); return 0; default: print_help(); return 1; } } if (argc != 2 && argc != 3) { print_help(); return 1; } max = strtol(argv[1], &end, 10); if (argv[1][0] == '\0' || *end != '\0') { fprintf(stderr, "ERROR: Invalid range value1 '%s'\n\n", argv[optind]); print_help(); return 1; } if (argc == 3) { min = strtol(argv[2], &end, 10); if (argv[2][0] == '\0' || *end != '\0') { fprintf(stderr, "ERROR: Invalid range value2 '%s'\n\n", argv[optind+1]); print_help(); return 1; } } srandom(get_seed()); rval = (min > max) ? rand_range(max, min) : rand_range(min, max); printf("%ld\n", rval); return 0; }