obfusc.c

   1 /*
   2  * Stand-alone tool to access the Puzzles obfuscation algorithm.
   3  *
   4  * To deobfuscate, use "obfusc -d":
   5  *
   6  *   obfusc -d                 reads binary data from stdin, writes to stdout
   7  *   obfusc -d <hex string>    works on the given hex string instead of stdin
   8  *   obfusc -d -h              writes a hex string instead of binary to stdout
   9  *
  10  * To obfuscate, "obfusc -e":
  11  *
  12  *   obfusc -e                 reads binary from stdin, writes hex to stdout
  13  *   obfusc -e <hex string>    works on the given hex string instead of stdin
  14  *   obfusc -e -b              writes binary instead of text to stdout
  15  *
  16  * The default output format is hex for -e and binary for -d
  17  * because that's the way obfuscation is generally used in
  18  * Puzzles. Either of -b and -h can always be specified to set it
  19  * explicitly.
  20  *
  21  * Data read from standard input is assumed always to be binary;
  22  * data provided on the command line is taken to be hex.
  23  */
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <stdarg.h>
  28 #include <string.h>
  29 #include <errno.h>
  30
  31 #include "puzzles.h"
  32
  33 int main(int argc, char **argv)
  34 {
  35     enum { BINARY, DEFAULT, HEX } outputmode = DEFAULT;
  36     char *inhex = NULL;
  37     unsigned char *data;
  38     int datalen;
  39     int decode = -1;
  40     int doing_opts = TRUE;
  41
  42     while (--argc > 0) {
  43         char *p = *++argv;
  44
  45         if (doing_opts && *p == '-') {
  46             if (!strcmp(p, "--")) {
  47                 doing_opts = 0;
  48                 continue;
  49             }
  50             p++;
  51             while (*p) {
  52                 switch (*p) {
  53                   case 'e':
  54                     decode = 0;
  55                     break;
  56                   case 'd':
  57                     decode = 1;
  58                     break;
  59                   case 'b':
  60                     outputmode = BINARY;
  61                     break;
  62                   case 'h':
  63                     outputmode = HEX;
  64                     break;
  65                   default:
  66                     fprintf(stderr, "obfusc: unrecognised option '-%c'\n",
  67                             *p);
  68                     return 1;
  69                 }
  70                 p++;
  71             }
  72         } else {
  73             if (!inhex) {
  74                 inhex = p;
  75             } else {
  76                 fprintf(stderr, "obfusc: expected at most one argument\n");
  77                 return 1;
  78             }
  79         }
  80     }
  81
  82     if (decode < 0) {
  83         fprintf(stderr, "usage: obfusc < -e | -d > [ -b | -h ] [hex data]\n");
  84         return 0;
  85     }
  86
  87     if (outputmode == DEFAULT)
  88         outputmode = (decode ? BINARY : HEX);
  89
  90     if (inhex) {
  91         datalen = strlen(inhex) / 2;
  92         data = hex2bin(inhex, datalen);
  93     } else {
  94         int datasize = 4096;
  95         datalen = 0;
  96         data = snewn(datasize, unsigned char);
  97         while (1) {
  98             int ret = fread(data + datalen, 1, datasize - datalen, stdin);
  99             if (ret < 0) {
 100                 fprintf(stderr, "obfusc: read: %s\n", strerror(errno));
 101                 return 1;
 102             } else if (ret == 0) {
 103                 break;
 104             } else {
 105                 datalen += ret;
 106                 if (datasize - datalen < 4096) {
 107                     datasize = datalen * 5 / 4 + 4096;
 108                     data = sresize(data, datasize, unsigned char);
 109                 }
 110             }
 111         }
 112     }
 113
 114     obfuscate_bitmap(data, datalen * 8, decode);
 115
 116     if (outputmode == BINARY) {
 117         int ret = fwrite(data, 1, datalen, stdout);
 118         if (ret < 0) {
 119             fprintf(stderr, "obfusc: write: %s\n", strerror(errno));
 120             return 1;
 121         }
 122     } else {
 123         int i;
 124         for (i = 0; i < datalen; i++)
 125             printf("%02x", data[i]);
 126         printf("\n");
 127     }
 128
 129     return 0;
 130 }