1 /* vi: set sw=4 ts=4: */
3 * cksum - calculate the CRC32 checksum of a file
5 * Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
10 //config: bool "cksum (4.2 kb)"
13 //config: cksum is used to calculate the CRC32 checksum of a file.
15 //applet:IF_CKSUM(APPLET_NOEXEC(cksum, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum))
16 /* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
18 //kbuild:lib-$(CONFIG_CKSUM) += cksum.o
20 //usage:#define cksum_trivial_usage
22 //usage:#define cksum_full_usage "\n\n"
23 //usage: "Calculate the CRC32 checksums of FILEs"
26 #include "common_bufsiz.h"
28 /* This is a NOEXEC applet. Be very careful! */
30 int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
31 int cksum_main(int argc UNUSED_PARAM, char **argv)
33 uint32_t *crc32_table = crc32_filltable(NULL, 1);
34 int exit_code = EXIT_SUCCESS;
37 getopt32(argv, ""); /* coreutils 6.9 compat */
43 setup_common_bufsiz();
47 int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
50 exit_code = EXIT_FAILURE;
56 #define read_buf bb_common_bufsiz1
59 int bytes_read = safe_read(fd, read_buf, COMMON_BUFSIZE);
61 filesize += bytes_read;
63 /* Checksum filesize bytes, LSB first, and exit */
65 fd = -1; /* break flag */
69 read_buf[bytes_read++] = (uint8_t)t;
73 crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
79 printf((*argv ? "%u %"OFF_FMT"u %s\n" : "%u %"OFF_FMT"u\n"),
80 (unsigned)crc, filesize, *argv);
81 } while (*argv && *++argv);
83 fflush_stdout_and_exit(exit_code);