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 |