[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * cksum - calculate the CRC32 checksum of a file
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| 4 | *
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| 5 | * Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
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[1765] | 6 | *
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[2725] | 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 8 | */
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[3232] | 9 |
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| 10 | //usage:#define cksum_trivial_usage
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| 11 | //usage: "FILES..."
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| 12 | //usage:#define cksum_full_usage "\n\n"
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| 13 | //usage: "Calculate the CRC32 checksums of FILES"
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| 14 |
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[1765] | 15 | #include "libbb.h"
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[821] | 16 |
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[2725] | 17 | /* This is a NOEXEC applet. Be very careful! */
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| 18 |
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| 19 | int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 20 | int cksum_main(int argc UNUSED_PARAM, char **argv)
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[1765] | 21 | {
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| 22 | uint32_t *crc32_table = crc32_filltable(NULL, 1);
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[821] | 23 | uint32_t crc;
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[2725] | 24 | off_t length, filesize;
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[821] | 25 | int bytes_read;
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[2725] | 26 | int exit_code = EXIT_SUCCESS;
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[1765] | 27 |
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[2725] | 28 | #if ENABLE_DESKTOP
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| 29 | getopt32(argv, ""); /* coreutils 6.9 compat */
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| 30 | argv += optind;
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| 31 | #else
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| 32 | argv++;
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| 33 | #endif
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[1765] | 34 |
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[821] | 35 | do {
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[2725] | 36 | int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
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[1765] | 37 |
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[2725] | 38 | if (fd < 0) {
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| 39 | exit_code = EXIT_FAILURE;
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| 40 | continue;
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| 41 | }
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[821] | 42 | crc = 0;
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| 43 | length = 0;
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[1765] | 44 |
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| 45 | #define read_buf bb_common_bufsiz1
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[2725] | 46 | while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) {
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[2859] | 47 | length += bytes_read;
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[2725] | 48 | crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
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[821] | 49 | }
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[2725] | 50 | close(fd);
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[1765] | 51 |
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[821] | 52 | filesize = length;
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[1765] | 53 |
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[2725] | 54 | while (length) {
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| 55 | crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length];
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| 56 | /* must ensure that shift is unsigned! */
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| 57 | if (sizeof(length) <= sizeof(unsigned))
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| 58 | length = (unsigned)length >> 8;
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| 59 | else if (sizeof(length) <= sizeof(unsigned long))
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| 60 | length = (unsigned long)length >> 8;
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| 61 | else
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| 62 | length = (unsigned long long)length >> 8;
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[821] | 63 | }
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[2725] | 64 | crc = ~crc;
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[1765] | 65 |
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[2725] | 66 | printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"),
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| 67 | crc, filesize, *argv);
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| 68 | } while (*argv && *++argv);
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[1765] | 69 |
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[2725] | 70 | fflush_stdout_and_exit(exit_code);
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[821] | 71 | }
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