LXR busybox/coreutils/cksum.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * cksum - calculate the CRC32 checksum of a file
   4 *
   5 * Copyright (C) 2006 by Rob Sullivan, with ideas from code by Walter Harms
   6 *
   7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8 */
   9//config:config CKSUM
  10//config:       bool "cksum (4.2 kb)"
  11//config:       default y
  12//config:       help
  13//config:       cksum is used to calculate the CRC32 checksum of a file.
  14
  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. */
  17
  18//kbuild:lib-$(CONFIG_CKSUM) += cksum.o
  19
  20//usage:#define cksum_trivial_usage
  21//usage:       "FILE..."
  22//usage:#define cksum_full_usage "\n\n"
  23//usage:       "Calculate the CRC32 checksums of FILEs"
  24
  25#include "libbb.h"
  26#include "common_bufsiz.h"
  27
  28/* This is a NOEXEC applet. Be very careful! */
  29
  30int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  31int cksum_main(int argc UNUSED_PARAM, char **argv)
  32{
  33        uint32_t *crc32_table = crc32_filltable(NULL, 1);
  34        int exit_code = EXIT_SUCCESS;
  35
  36#if ENABLE_DESKTOP
  37        getopt32(argv, ""); /* coreutils 6.9 compat */
  38        argv += optind;
  39#else
  40        argv++;
  41#endif
  42
  43        setup_common_bufsiz();
  44        do {
  45                uint32_t crc;
  46                off_t filesize;
  47                int fd = open_or_warn_stdin(*argv ? *argv : bb_msg_standard_input);
  48
  49                if (fd < 0) {
  50                        exit_code = EXIT_FAILURE;
  51                        continue;
  52                }
  53
  54                crc = 0;
  55                filesize = 0;
  56#define read_buf bb_common_bufsiz1
  57                for (;;) {
  58                        uoff_t t;
  59                        int bytes_read = safe_read(fd, read_buf, COMMON_BUFSIZE);
  60                        if (bytes_read > 0) {
  61                                filesize += bytes_read;
  62                        } else {
  63                                /* Checksum filesize bytes, LSB first, and exit */
  64                                close(fd);
  65                                fd = -1; /* break flag */
  66                                t = filesize;
  67                                bytes_read = 0;
  68                                while (t != 0) {
  69                                        read_buf[bytes_read++] = (uint8_t)t;
  70                                        t >>= 8;
  71                                }
  72                        }
  73                        crc = crc32_block_endian1(crc, read_buf, bytes_read, crc32_table);
  74                        if (fd < 0)
  75                                break;
  76                }
  77
  78                crc = ~crc;
  79                printf((*argv ? "%u %"OFF_FMT"u %s\n" : "%u %"OFF_FMT"u\n"),
  80                                (unsigned)crc, filesize, *argv);
  81        } while (*argv && *++argv);
  82
  83        fflush_stdout_and_exit(exit_code);
  84}
  85