1 /* 2 * Copyright (c) 2016 Red Hat Inc. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License as 6 * published by the Free Software Foundation; either version 2 of 7 * the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it would be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 17 * 18 * Author: Chunyu Hu <chuhu (at) redhat.com> 19 * 20 */ 21 22 #include <stdio.h> 23 #include <unistd.h> 24 #include <stdlib.h> 25 #include <string.h> 26 #include <sys/time.h> 27 28 static void print_help(void) 29 { 30 printf("Usage: tst_random <value1> [value2]\n"); 31 printf(" Generated random will be between value1 and value2.\n"); 32 printf(" If only value1 is specified, value2 will treated as 0.\n"); 33 } 34 35 static int get_seed(void) 36 { 37 struct timeval tv; 38 gettimeofday(&tv, NULL); 39 return tv.tv_usec; 40 } 41 42 static long rand_range(long min, long max) 43 { 44 return random() % (max - min + 1) + min; 45 } 46 47 int main(int argc, char *argv[]) 48 { 49 int opt; 50 long min = 0, max = 0; 51 long rval = 0; 52 char *end; 53 54 while ((opt = getopt(argc, argv, ":h")) != -1) { 55 switch (opt) { 56 case 'h': 57 print_help(); 58 return 0; 59 default: 60 print_help(); 61 return 1; 62 } 63 } 64 65 if (argc != 2 && argc != 3) { 66 print_help(); 67 return 1; 68 } 69 70 max = strtol(argv[1], &end, 10); 71 if (argv[1][0] == '\0' || *end != '\0') { 72 fprintf(stderr, "ERROR: Invalid range value1 '%s'\n\n", 73 argv[optind]); 74 print_help(); 75 return 1; 76 } 77 78 if (argc == 3) { 79 min = strtol(argv[2], &end, 10); 80 if (argv[2][0] == '\0' || *end != '\0') { 81 fprintf(stderr, "ERROR: Invalid range value2 '%s'\n\n", 82 argv[optind+1]); 83 print_help(); 84 return 1; 85 } 86 } 87 88 srandom(get_seed()); 89 rval = (min > max) ? rand_range(max, min) : rand_range(min, max); 90 printf("%ld\n", rval); 91 92 return 0; 93 } 94
