obfuscate.c

   1 /*
   2  * Example trivial client program that uses the sparse library
   3  * to tokenize, pre-process and parse a C file, and prints out
   4  * the results.
   5  *
   6  * Copyright (C) 2003 Transmeta Corp.
   7  *               2003 Linus Torvalds
   8  *
   9  *  Licensed under the Open Software License version 1.1
  10  */
  11 #include <stdarg.h>
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <string.h>
  15 #include <ctype.h>
  16 #include <unistd.h>
  17 #include <fcntl.h>
  18
  19 #include "lib.h"
  20 #include "token.h"
  21 #include "parse.h"
  22 #include "symbol.h"
  23 #include "expression.h"
  24
  25 static void emit_blob(struct symbol *sym)
  26 {
  27         int size = sym->bit_size;
  28         int alignment = sym->ctype.alignment;
  29         const char *name = show_ident(sym->ident);
  30
  31         if (size <= 0) {
  32                 warn(sym->pos, "emitting insized symbol");
  33                 size = 8;
  34         }
  35         if (size & 7)
  36                 warn(sym->pos, "emitting symbol of size %d bits\n", size);
  37         size = (size+7) >> 3;
  38         if (alignment < 1)
  39                 alignment = 1;
  40         if (!(size & (alignment-1))) {
  41                 switch (alignment) {
  42                 case 1:
  43                         printf("unsigned char %s[%d];\n", name, size);
  44                         return;
  45                 case 2:
  46                         printf("unsigned short %s[%d];\n", name, (size+1) >> 1);
  47                         return;
  48                 case 4:
  49                         printf("unsigned int %s[%d];\n", name, (size+3) >> 2);
  50                         return;
  51                 }
  52         }
  53         printf("unsigned char %s[%d] __attribute__((aligned(%d)));\n",
  54                 name, size, alignment);
  55         return;
  56 }
  57
  58 static void emit_fn(struct symbol *sym)
  59 {
  60         const char *name = show_ident(sym->ident);
  61         printf("%s();\n", name);
  62 }
  63
  64 void emit_symbol(struct symbol *sym, void *_parent, int flags)
  65 {
  66         struct symbol *ctype;
  67
  68         evaluate_symbol(sym);
  69         if (sym->type != SYM_NODE) {
  70                 warn(sym->pos, "I really want to emit nodes, not pure types!");
  71                 return;
  72         }
  73
  74         ctype = sym->ctype.base_type;
  75         if (!ctype)
  76                 return;
  77         switch (ctype->type) {
  78         case SYM_NODE:
  79         case SYM_PTR:
  80         case SYM_ARRAY:
  81         case SYM_STRUCT:
  82         case SYM_UNION:
  83         case SYM_BASETYPE:
  84                 emit_blob(sym);
  85                 return;
  86         case SYM_FN:
  87                 emit_fn(sym);
  88                 return;
  89         default:
  90                 warn(sym->pos, "what kind of strange node do you want me to emit again?");
  91                 return;
  92         }
  93 }
  94
  95 int main(int argc, char **argv)
  96 {
  97         int fd;
  98         char *filename = argv[1];
  99         struct token *token;
 100         struct symbol_list *list = NULL;
 101
 102         // Initialize symbol stream first, so that we can add defines etc
 103         init_symbols();
 104
 105         fd = open(filename, O_RDONLY);
 106         if (fd < 0)
 107                 die("No such file: %s", argv[1]);
 108
 109         // Initialize type system
 110         init_ctype();
 111
 112         // Tokenize the input stream
 113         token = tokenize(filename, fd, NULL);
 114         close(fd);
 115
 116         // Pre-process the stream
 117         token = preprocess(token);
 118
 119         // Parse the resulting C code
 120         translation_unit(token, &list);
 121
 122         // Do type evaluation and simplify
 123         symbol_iterate(list, emit_symbol, NULL);
 124
 125         return 0;
 126 }