md5sum.c

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

          /* A valid line does not end with a backslash.  */
          return FALSE;
        }
        ++i;
        switch (s[i++]) {
         case 'n':
          *dst++ = '\n';
          break;
         case '\\':
          *dst++ = '\\';
          break;
         default:
          /* Only `\' or `n' may follow a backslash.  */
          return FALSE;
        }
        break;

       case '\0':
        /* The file name may not contain a NUL.  */
        return FALSE;
        break;

       default:
        *dst++ = s[i++];
        break;
      }
    }
    *dst = '\0';
  }
  return TRUE;
}

static inline int hex_digits(unsigned char const *s)
{
  while (*s) {
    if (!ISXDIGIT(*s))
      return TRUE;
    ++s;
  }
  return FALSE;
}

/* An interface to md5_stream.  Operate on FILENAME (it may be "-") and
   put the result in *MD5_RESULT.  Return non-zero upon failure, zero
   to indicate success.  */
static int md5_file(const char *filename,
                    unsigned char *md5_result)
{
  FILE *fp;

  if (filename[0] == '-' && filename[1] == '\0') {
    have_read_stdin = 1;
    fp = stdin;
  } else {
    fp = wfopen(filename, "r");
    if (fp == NULL)
      return FALSE;
    }

  if (md5_stream(fp, md5_result)) {
    perror_msg("%s", filename);

    if (fp != stdin)
      fclose(fp);
    return FALSE;
  }

  if (fp != stdin && fclose(fp) == EOF) {
    perror_msg("%s", filename);
    return FALSE;
  }

  return TRUE;
}

static int md5_check(const char *checkfile_name)
{
  FILE *checkfile_stream;
  int n_properly_formated_lines = 0;
  int n_mismatched_checksums = 0;
  int n_open_or_read_failures = 0;
  unsigned char md5buffer[16];
  size_t line_number;
  char line[BUFSIZ];

  if (checkfile_name[0] == '-' && checkfile_name[1] == '\0') {
    have_read_stdin = 1;
    checkfile_stream = stdin;
  } else {
    checkfile_stream = wfopen(checkfile_name, "r");
    if (checkfile_stream == NULL)
      return FALSE;
    }

  line_number = 0;

  do {
    char *filename;
    unsigned char *md5num;
    int line_length;

    ++line_number;

    fgets(line, BUFSIZ-1, checkfile_stream);
    line_length = strlen(line);

    if (line_length <= 0 || line==NULL)
      break;

    /* Ignore comment lines, which begin with a '#' character.  */
    if (line[0] == '#')
      continue;

    /* Remove any trailing newline.  */
    if (line[line_length - 1] == '\n')
      line[--line_length] = '\0';

    if (split_3(line, line_length, &md5num, &filename)
        || !hex_digits(md5num)) {
      if (warn) {
        error_msg("%s: %lu: improperly formatted MD5 checksum line",
                 checkfile_name, (unsigned long) line_number);
      }
    } else {
      static const char bin2hex[] = {
        '0', '1', '2', '3',
        '4', '5', '6', '7',
        '8', '9', 'a', 'b',
        'c', 'd', 'e', 'f'
      };

      ++n_properly_formated_lines;

      if (md5_file(filename, md5buffer)) {
        ++n_open_or_read_failures;
        if (!status_only) {
          printf("%s: FAILED open or read\n", filename);
          fflush(stdout);
        }
      } else {
        size_t cnt;
        /* Compare generated binary number with text representation
           in check file.  Ignore case of hex digits.  */
        for (cnt = 0; cnt < 16; ++cnt) {
          if (tolower(md5num[2 * cnt])
              != bin2hex[md5buffer[cnt] >> 4]
              || (tolower(md5num[2 * cnt + 1])
                  != (bin2hex[md5buffer[cnt] & 0xf])))
            break;
        }
        if (cnt != 16)
          ++n_mismatched_checksums;

        if (!status_only) {
          printf("%s: %s\n", filename,
                 (cnt != 16 ? "FAILED" : "OK"));
          fflush(stdout);
        }
      }
    }
  }

  while (!feof(checkfile_stream) && !ferror(checkfile_stream));

  if (ferror(checkfile_stream)) {
    error_msg("%s: read error", checkfile_name);
    return FALSE;
  }

  if (checkfile_stream != stdin && fclose(checkfile_stream) == EOF) {
    perror_msg("md5sum: %s", checkfile_name);
    return FALSE;
  }

  if (n_properly_formated_lines == 0) {
    /* Warn if no tests are found.  */
    error_msg("%s: no properly formatted MD5 checksum lines found",
             checkfile_name);
    return FALSE;
  } else {
    if (!status_only) {
      int n_computed_checkums = (n_properly_formated_lines
                                 - n_open_or_read_failures);

      if (n_open_or_read_failures > 0) {
        error_msg("WARNING: %d of %d listed files could not be read",
                 n_open_or_read_failures, n_properly_formated_lines);
        return FALSE;
      }

      if (n_mismatched_checksums > 0) {
        error_msg("WARNING: %d of %d computed checksums did NOT match",
                 n_mismatched_checksums, n_computed_checkums);
        return FALSE;
      }
    }
  }

  return ((n_properly_formated_lines > 0 && n_mismatched_checksums == 0
           && n_open_or_read_failures == 0) ? 0 : 1);
}

int md5sum_main(int argc,
                char **argv)
{
  unsigned char md5buffer[16];
  int do_check = 0;
  int opt;
  char **string = NULL;
  size_t n_strings = 0;
  size_t err = 0;
  char file_type_specified = 0;
  char binary = 0;

  while ((opt = getopt(argc, argv, "g:bcstw")) != -1) {
    switch (opt) {
     case 'g': { /* read a string */
       if (string == NULL)
         string = (char **) xmalloc ((argc - 1) * sizeof (char *));

       string[n_strings++] = optarg;
       break;
     }

     case 'b': /* read files in binary mode */
      file_type_specified = 1;
      binary = 1;
      break;

     case 'c': /* check MD5 sums against given list */
      do_check = 1;
      break;

     case 's':  /* don't output anything, status code shows success */
      status_only = 1;
      warn = 0;
      break;

     case 't': /* read files in text mode (default) */
      file_type_specified = 1;
      binary = 0;
      break;

     case 'w': /* warn about improperly formated MD5 checksum lines */
      status_only = 0;
      warn = 1;
      break;

     default:
      show_usage();
    }
  }

  if (file_type_specified && do_check) {
    error_msg_and_die("the -b and -t options are meaningless when verifying checksums");
  }

  if (n_strings > 0 && do_check) {
    error_msg_and_die("the -g and -c options are mutually exclusive");
  }

  if (status_only && !do_check) {
    error_msg_and_die("the -s option is meaningful only when verifying checksums");
  }

  if (warn && !do_check) {
    error_msg_and_die("the -w option is meaningful only when verifying checksums");
  }

  if (n_strings > 0) {
    size_t i;

    if (optind < argc) {
      error_msg_and_die("no files may be specified when using -g");
    }
    for (i = 0; i < n_strings; ++i) {
      size_t cnt;
      md5_buffer (string[i], strlen (string[i]), md5buffer);

      for (cnt = 0; cnt < 16; ++cnt)
        printf ("%02x", md5buffer[cnt]);

      printf ("  \"%s\"\n", string[i]);
    }
  } else if (do_check) {
    if (optind + 1 < argc) {
      error_msg("only one argument may be specified when using -c");
    }

    err = md5_check ((optind == argc) ? "-" : argv[optind]);
  } else {
    if (optind == argc)
      argv[argc++] = "-";

    for (; optind < argc; ++optind) {
      int fail;
      char *file = argv[optind];

      fail = md5_file (file, md5buffer);
      err |= fail;
      if (!fail && file[0]=='-' && file[1] == '\0') {
	  size_t i;
	  for (i = 0; i < 16; ++i)
	      printf ("%02x", md5buffer[i]);
	  putchar ('\n');
      } else if (!fail) {
        size_t i;
        /* Output a leading backslash if the file name contains
           a newline or backslash.  */
        if (strchr (file, '\n') || strchr (file, '\\'))
          putchar ('\\');

        for (i = 0; i < 16; ++i)
          printf ("%02x", md5buffer[i]);

        putchar (' ');
        if (binary)
          putchar ('*');
        else
          putchar (' ');

        /* Translate each NEWLINE byte to the string, "\\n",
           and each backslash to "\\\\".  */
        for (i = 0; i < strlen (file); ++i) {
          switch (file[i]) {
           case '\n':
            fputs ("\\n", stdout);
            break;

           case '\\':
            fputs ("\\\\", stdout);
            break;

           default:
            putchar (file[i]);
            break;
          }
        }
        putchar ('\n');
      }
    }
  }

  if (fclose (stdout) == EOF) {
    error_msg_and_die("write error");
  }

  if (have_read_stdin && fclose (stdin) == EOF) {
    error_msg_and_die("standard input");
  }

  if (err == 0)
	  return EXIT_SUCCESS;
  else
	  return EXIT_FAILURE;
}