blob: ac0b0c319ec1a9b39fee2db7b76a608ba6aebde9
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * cksum - calculate the CRC32 checksum of a file |
4 | * |
5 | * Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms |
6 | * |
7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
8 | */ |
9 | |
10 | //usage:#define cksum_trivial_usage |
11 | //usage: "FILES..." |
12 | //usage:#define cksum_full_usage "\n\n" |
13 | //usage: "Calculate the CRC32 checksums of FILES" |
14 | |
15 | #include "libbb.h" |
16 | |
17 | /* This is a NOEXEC applet. Be very careful! */ |
18 | |
19 | int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
20 | int cksum_main(int argc UNUSED_PARAM, char **argv) |
21 | { |
22 | uint32_t *crc32_table = crc32_filltable(NULL, 1); |
23 | uint32_t crc; |
24 | off_t length, filesize; |
25 | int bytes_read; |
26 | int exit_code = EXIT_SUCCESS; |
27 | |
28 | #if ENABLE_DESKTOP |
29 | getopt32(argv, ""); /* coreutils 6.9 compat */ |
30 | argv += optind; |
31 | #else |
32 | argv++; |
33 | #endif |
34 | |
35 | do { |
36 | int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input); |
37 | |
38 | if (fd < 0) { |
39 | exit_code = EXIT_FAILURE; |
40 | continue; |
41 | } |
42 | crc = 0; |
43 | length = 0; |
44 | |
45 | #define read_buf bb_common_bufsiz1 |
46 | while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) { |
47 | length += bytes_read; |
48 | crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table); |
49 | } |
50 | close(fd); |
51 | |
52 | filesize = length; |
53 | |
54 | while (length) { |
55 | crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length]; |
56 | /* must ensure that shift is unsigned! */ |
57 | if (sizeof(length) <= sizeof(unsigned)) |
58 | length = (unsigned)length >> 8; |
59 | else if (sizeof(length) <= sizeof(unsigned long)) |
60 | length = (unsigned long)length >> 8; |
61 | else |
62 | length = (unsigned long long)length >> 8; |
63 | } |
64 | crc = ~crc; |
65 | |
66 | printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"), |
67 | crc, filesize, *argv); |
68 | } while (*argv && *++argv); |
69 | |
70 | fflush_stdout_and_exit(exit_code); |
71 | } |
72 |