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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6 | *
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7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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8 | */
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9 | #include "libbb.h"
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10 |
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11 | /* This is a NOEXEC applet. Be very careful! */
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12 |
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13 | int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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14 | int cksum_main(int argc UNUSED_PARAM, char **argv)
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15 | {
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16 | uint32_t *crc32_table = crc32_filltable(NULL, 1);
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17 | uint32_t crc;
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18 | off_t length, filesize;
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19 | int bytes_read;
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20 | int exit_code = EXIT_SUCCESS;
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21 |
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22 | #if ENABLE_DESKTOP
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23 | getopt32(argv, ""); /* coreutils 6.9 compat */
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24 | argv += optind;
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25 | #else
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26 | argv++;
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27 | #endif
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28 |
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29 | do {
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30 | int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
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31 |
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32 | if (fd < 0) {
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33 | exit_code = EXIT_FAILURE;
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34 | continue;
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35 | }
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36 | crc = 0;
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37 | length = 0;
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38 |
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39 | #define read_buf bb_common_bufsiz1
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40 | while ((bytes_read = safe_read(fd, read_buf, sizeof(read_buf))) > 0) {
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41 | length += bytes_read;
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42 | crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
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43 | }
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44 | close(fd);
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45 |
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46 | filesize = length;
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47 |
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48 | while (length) {
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49 | crc = (crc << 8) ^ crc32_table[(uint8_t)(crc >> 24) ^ (uint8_t)length];
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50 | /* must ensure that shift is unsigned! */
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51 | if (sizeof(length) <= sizeof(unsigned))
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52 | length = (unsigned)length >> 8;
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53 | else if (sizeof(length) <= sizeof(unsigned long))
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54 | length = (unsigned long)length >> 8;
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55 | else
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56 | length = (unsigned long long)length >> 8;
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57 | }
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58 | crc = ~crc;
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59 |
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60 | printf((*argv ? "%"PRIu32" %"OFF_FMT"i %s\n" : "%"PRIu32" %"OFF_FMT"i\n"),
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61 | crc, filesize, *argv);
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62 | } while (*argv && *++argv);
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63 |
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64 | fflush_stdout_and_exit(exit_code);
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65 | }
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