busybox/coreutils/cksum.c

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/* vi: set sw=4 ts=4: */
/*
* cksum - calculate the CRC32 checksum of a file
*
* Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config CKSUM
//config: bool "cksum (4.1 kb)"
//config: default y
//config:
//config:config CRC32
//config: bool "crc32 (4.1 kb)"
//config: default y
// APPLET_NOEXEC:name main location suid_type help
//applet:IF_CKSUM(APPLET_NOEXEC(cksum, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum))
//applet:IF_CRC32(APPLET_NOEXEC(crc32, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum))
/* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
//kbuild:lib-$(CONFIG_CKSUM) += cksum.o
//kbuild:lib-$(CONFIG_CRC32) += cksum.o
//usage:#define cksum_trivial_usage
//usage: "FILE..."
//usage:#define cksum_full_usage "\n\n"
//usage: "Calculate CRC32 checksum of FILEs"
#include "libbb.h"
#include "common_bufsiz.h"
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/* This is a NOEXEC applet. Be very careful! */
#define IS_CKSUM (ENABLE_CKSUM && (!ENABLE_CRC32 || applet_name[1] == 'k'))
#define IS_CRC32 (ENABLE_CRC32 && (!ENABLE_CKSUM || applet_name[1] == 'r'))
int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int cksum_main(int argc UNUSED_PARAM, char **argv)
{
uint32_t *crc32_table = crc32_filltable(NULL, IS_CKSUM);
int exit_code = EXIT_SUCCESS;
#if ENABLE_DESKTOP
getopt32(argv, ""); /* cksum coreutils 6.9 compat */
argv += optind;
#else
argv++;
#endif
setup_common_bufsiz();
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do {
uint32_t crc;
IF_CKSUM(off_t filesize;)
const char *fname = *argv ? *argv : bb_msg_standard_input;
int fd = open_or_warn_stdin(fname);
if (fd < 0) {
exit_code = EXIT_FAILURE;
continue;
}
crc = IS_CKSUM ? 0 : 0xffffffff;
IF_CKSUM(filesize = 0;)
#define read_buf bb_common_bufsiz1
for (;;) {
int bytes_read = safe_read(fd, read_buf, COMMON_BUFSIZE);
if (bytes_read < 0)
bb_simple_perror_msg_and_die(fname);
if (bytes_read > 0) {
IF_CKSUM(filesize += bytes_read;)
} else {
IF_CKSUM(uoff_t t;)
close(fd);
if (IS_CRC32)
break;
#if ENABLE_CKSUM
fd = -1; /* break flag */
/* Checksum filesize bytes, LSB first */
t = filesize;
/*bytes_read = 0; - already is */
while (t != 0) {
read_buf[bytes_read++] = (uint8_t)t;
t >>= 8;
}
#endif
}
crc = (IS_CKSUM ? crc32_block_endian1 : crc32_block_endian0)(crc, read_buf, bytes_read, crc32_table);
if (ENABLE_CKSUM && fd < 0)
break;
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}
crc = ~crc;
#if ENABLE_CKSUM
if (IS_CKSUM)
printf((*argv ? "%u %"OFF_FMT"u %s\n" : "%u %"OFF_FMT"u\n"),
(unsigned)crc, filesize, *argv);
else
#endif
printf((*argv ? "%08x %s\n" : "%08x\n"),
(unsigned)crc, *argv);
} while (*argv && *++argv);
fflush_stdout_and_exit(exit_code);
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}