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