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 (4.3 kb)"
  11 //config:       default y
  12 //config:
  13 //config:config CRC32
  14 //config:       bool "crc32 (4.2 kb)"
  15 //config:       default y
  16
  17 //                APPLET_NOEXEC:name   main   location        suid_type     help
  18 //applet:IF_CKSUM(APPLET_NOEXEC(cksum, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum))
  19 //applet:IF_CRC32(APPLET_NOEXEC(crc32, cksum, BB_DIR_USR_BIN, BB_SUID_DROP, cksum))
  20 /* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
  21
  22 //kbuild:lib-$(CONFIG_CKSUM) += cksum.o
  23 //kbuild:lib-$(CONFIG_CRC32) += cksum.o
  24
  25 //usage:#define cksum_trivial_usage
  26 //usage:       "FILE..."
  27 //usage:#define cksum_full_usage "\n\n"
  28 //usage:       "Calculate CRC32 checksum of FILEs"
  29
  30 #include "libbb.h"
  31 #include "common_bufsiz.h"
  32
  33 /* This is a NOEXEC applet. Be very careful! */
  34
  35 #define IS_CKSUM (ENABLE_CKSUM && (!ENABLE_CRC32 || applet_name[1] == 'k'))
  36 #define IS_CRC32 (ENABLE_CRC32 && (!ENABLE_CKSUM || applet_name[1] == 'r'))
  37
  38 int cksum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  39 int cksum_main(int argc UNUSED_PARAM, char **argv)
  40 {
  41         uint32_t *crc32_table = crc32_filltable(NULL, IS_CKSUM);
  42         exitcode_t exit_code = EXIT_SUCCESS;
  43
  44 #if ENABLE_DESKTOP
  45         getopt32(argv, ""); /* cksum coreutils 6.9 compat */
  46         argv += optind;
  47 #else
  48         argv++;
  49 #endif
  50
  51         setup_common_bufsiz();
  52         do {
  53                 uint32_t crc;
  54                 IF_CKSUM(off_t filesize;)
  55                 const char *fname = *argv ? *argv : bb_msg_standard_input;
  56                 int fd = open_or_warn_stdin(fname);
  57
  58                 if (fd < 0) {
  59                         exit_code = EXIT_FAILURE;
  60                         continue;
  61                 }
  62
  63                 crc = IS_CKSUM ? 0 : 0xffffffff;
  64                 IF_CKSUM(filesize = 0;)
  65 #define read_buf bb_common_bufsiz1
  66                 for (;;) {
  67                         int bytes_read = safe_read(fd, read_buf, COMMON_BUFSIZE);
  68                         if (bytes_read < 0)
  69                                 bb_simple_perror_msg_and_die(fname);
  70                         if (bytes_read > 0) {
  71                                 IF_CKSUM(filesize += bytes_read;)
  72                         } else {
  73                                 IF_CKSUM(uoff_t t;)
  74
  75                                 close(fd);
  76                                 if (IS_CRC32)
  77                                         break;
  78 #if ENABLE_CKSUM
  79                                 fd = -1; /* break flag */
  80                                 /* Checksum filesize bytes, LSB first */
  81                                 t = filesize;
  82                                 /*bytes_read = 0; - already is */
  83                                 while (t != 0) {
  84                                         read_buf[bytes_read++] = (uint8_t)t;
  85                                         t >>= 8;
  86                                 }
  87 #endif
  88                         }
  89                         crc = (IS_CKSUM ? crc32_block_endian1 : crc32_block_endian0)(crc, read_buf, bytes_read, crc32_table);
  90                         if (ENABLE_CKSUM && fd < 0)
  91                                 break;
  92                 }
  93
  94                 crc = ~crc;
  95 #if ENABLE_CKSUM
  96                 if (IS_CKSUM)
  97                         printf((*argv ? "%u %"OFF_FMT"u %s\n" : "%u %"OFF_FMT"u\n"),
  98                                 (unsigned)crc, filesize, *argv);
  99                 else
 100 #endif
 101                         printf((*argv ? "%08x %s\n" : "%08x\n"),
 102                                 (unsigned)crc, *argv);
 103         } while (*argv && *++argv);
 104
 105         fflush_stdout_and_exit(exit_code);
 106 }