1 /* 2 * crcsum.c 3 * 4 * Copyright (C) 2013 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Public 8 * License. 9 * %End-Header% 10 */ 11 12 #include "config.h" 13 #include <stdio.h> 14 #include <stdlib.h> 15 #include <stdint.h> 16 #include <string.h> 17 #include <unistd.h> 18 #ifdef HAVE_GETOPT_H 19 #include <getopt.h> 20 #endif 21 #include <fcntl.h> 22 23 #include "et/com_err.h" 24 #include "ss/ss.h" 25 #include "ext2fs/ext2fs.h" 26 27 28 int main(int argc, char **argv) 29 { 30 int c; 31 uint32_t crc = ~0; 32 uint32_t (*csum_func)(uint32_t crc, unsigned char const *p, 33 size_t len); 34 FILE *f; 35 36 csum_func = ext2fs_crc32c_le; 37 38 while ((c = getopt (argc, argv, "h")) != EOF) { 39 switch (c) { 40 case 'h': 41 default: 42 com_err(argv[0], 0, "Usage: crcsum [file]\n"); 43 return 1; 44 } 45 } 46 47 if (optind == argc) 48 f = stdin; 49 else { 50 f = fopen(argv[optind], "r"); 51 if (!f) { 52 com_err(argv[0], errno, "while trying to open %s\n", 53 argv[optind]); 54 exit(1); 55 } 56 } 57 58 while (!feof(f)) { 59 unsigned char buf[4096]; 60 61 int c = fread(buf, 1, sizeof(buf), f); 62 63 if (c) 64 crc = csum_func(crc, buf, c); 65 } 66 printf("%u\n", crc); 67 return 0; 68 } 69
