bin2sh.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3
   4 static int syntax() {
   5         printf("bin2sh - converts a file into a shellscript which recreates "
   6                 "the file when run\nthe output is written to stdout\n"
   7                "bin2sh [-c N] filename\n"
   8                "where N is the number of chars per line\n");
   9         return 1;
  10 }
  11
  12 static int is_c_arg(char* s) {
  13         return s[0]=='-' && s[1]=='c' &&!s[2];
  14 }
  15 int main(int argc, char** argv) {
  16         if(argc == 1 || argc > 4 || argc == 3 ||
  17            (is_c_arg(argv[1]) && argc != 4)) return syntax();
  18         int f_arg = 1;
  19         unsigned cpl = 20;
  20         if(is_c_arg(argv[1])) {
  21                 f_arg = 3;
  22                 cpl = atoi(argv[2]);
  23                 if(!cpl) return syntax();
  24         }
  25         FILE *f = fopen(argv[f_arg], "r");
  26         if(!f) { perror("fopen"); return 1; }
  27         unsigned long long cnt = 0;
  28         unsigned char buf[1];
  29         static const char redir[][3] = {">", ">>"};
  30         int printed = 0;
  31         while(fread(buf, 1, 1, f)) {
  32                 if(!(cnt % cpl)) {
  33                         if(cnt) {
  34                                 printf("\" %s f", redir[printed]);
  35                                 printed = 1;
  36                         } else printf("#!/bin/sh");
  37                         printf("\n\necho -ne \"");
  38                 }
  39                 printf("\\x%02X", buf[0]);
  40                 cnt++;
  41         }
  42         if(cnt % cpl) printf("\" %s f\n", redir[printed]);
  43         fclose(f);
  44         return 0;
  45 }