85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* cksum - calculate the CRC32 checksum of a file
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*
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* Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config CKSUM
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//config: bool "cksum (4.1 kb)"
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//config: default y
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//config: help
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//config: cksum is used to calculate the CRC32 checksum of a file.
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//applet:IF_CKSUM(APPLET_NOEXEC(cksum, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum))
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/* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
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//kbuild:lib-$(CONFIG_CKSUM) += cksum.o
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//usage:#define cksum_trivial_usage
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//usage: "FILE..."
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//usage:#define cksum_full_usage "\n\n"
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//usage: "Calculate the CRC32 checksums of FILEs"
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#include "libbb.h"
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#include "common_bufsiz.h"
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/* This is a NOEXEC applet. Be very careful! */
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int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int cksum_main(int argc UNUSED_PARAM, char **argv)
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{
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uint32_t *crc32_table = crc32_filltable(NULL, 1);
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int exit_code = EXIT_SUCCESS;
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#if ENABLE_DESKTOP
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getopt32(argv, ""); /* coreutils 6.9 compat */
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argv += optind;
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#else
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argv++;
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#endif
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setup_common_bufsiz();
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do {
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uint32_t crc;
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off_t filesize;
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int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
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if (fd < 0) {
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exit_code = EXIT_FAILURE;
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continue;
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}
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crc = 0;
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filesize = 0;
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#define read_buf bb_common_bufsiz1
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for (;;) {
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uoff_t t;
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int bytes_read = safe_read(fd, read_buf, COMMON_BUFSIZE);
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if (bytes_read > 0) {
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filesize += bytes_read;
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} else {
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/* Checksum filesize bytes, LSB first, and exit */
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close(fd);
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fd = -1; /* break flag */
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t = filesize;
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bytes_read = 0;
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while (t != 0) {
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read_buf[bytes_read++] = (uint8_t)t;
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t >>= 8;
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}
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}
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crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
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if (fd < 0)
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break;
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}
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crc = ~crc;
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printf((*argv ? "%u %"OFF_FMT"u %s\n" : "%u %"OFF_FMT"u\n"),
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(unsigned)crc, filesize, *argv);
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} while (*argv && *++argv);
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fflush_stdout_and_exit(exit_code);
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}
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