blob: aeec0188dd09dfd7139d09ae594c4fabb4af6257
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 | //config:config CKSUM |
10 | //config: bool "cksum" |
11 | //config: default y |
12 | //config: help |
13 | //config: cksum is used to calculate the CRC32 checksum of a file. |
14 | |
15 | //applet:IF_CKSUM(APPLET_NOEXEC(cksum, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum)) |
16 | |
17 | //kbuild:lib-$(CONFIG_CKSUM) += cksum.o |
18 | |
19 | //usage:#define cksum_trivial_usage |
20 | //usage: "FILES..." |
21 | //usage:#define cksum_full_usage "\n\n" |
22 | //usage: "Calculate the CRC32 checksums of FILES" |
23 | |
24 | #include "libbb.h" |
25 | #include "common_bufsiz.h" |
26 | |
27 | /* This is a NOEXEC applet. Be very careful! */ |
28 | |
29 | int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
30 | int cksum_main(int argc UNUSED_PARAM, char **argv) |
31 | { |
32 | uint32_t *crc32_table = crc32_filltable(NULL, 1); |
33 | uint32_t crc; |
34 | off_t length, filesize; |
35 | int bytes_read; |
36 | int exit_code = EXIT_SUCCESS; |
37 | |
38 | #if ENABLE_DESKTOP |
39 | getopt32(argv, ""); /* coreutils 6.9 compat */ |
40 | argv += optind; |
41 | #else |
42 | argv++; |
43 | #endif |
44 | |
45 | setup_common_bufsiz(); |
46 | do { |
47 | int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input); |
48 | |
49 | if (fd < 0) { |
50 | exit_code = EXIT_FAILURE; |
51 | continue; |
52 | } |
53 | crc = 0; |
54 | length = 0; |
55 | |
56 | #define read_buf bb_common_bufsiz1 |
57 | while ((bytes_read = safe_read(fd, read_buf, COMMON_BUFSIZE)) > 0) { |
58 | length += bytes_read; |
59 | crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table); |
60 | } |
61 | close(fd); |
62 | |
63 | filesize = length; |
64 | |
65 | while (length) { |
66 | crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length]; |
67 | /* must ensure that shift is unsigned! */ |
68 | if (sizeof(length) <= sizeof(unsigned)) |
69 | length = (unsigned)length >> 8; |
70 | else if (sizeof(length) <= sizeof(unsigned long)) |
71 | length = (unsigned long)length >> 8; |
72 | else |
73 | length = (unsigned long long)length >> 8; |
74 | } |
75 | crc = ~crc; |
76 | |
77 | printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"), |
78 | crc, filesize, *argv); |
79 | } while (*argv && *++argv); |
80 | |
81 | fflush_stdout_and_exit(exit_code); |
82 | } |
83 |