#!/bin/bash

target="target \"test\""
c_target=$(echo "$target" | sed 's/\"/\\\"/g')

rm -rf "$target" 2>/dev/null
rm -f cd1.iso cd2.iso hook.so dummy 2>/dev/null

mkdir "$target"
dd if=/dev/urandom of="$target/bigfile" bs=1M count=5 2>/dev/null
for((i=0;i<10;i++)); do
  mkdir -p "$target/$i"
  dd if=/dev/urandom of="$target/$i/file" bs=1K count=1 2>/dev/null
done

function src() {
  cat <<EOF
#define _GNU_SOURCE
#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>

static const char target[] = "$c_target";

EOF
  fopen ""
  fopen "64"
}
function fopen() {
  cat <<EOF
FILE* fopen$1( const char * filename, const char * mode )
{
  typedef FILE* (*t_fopen$1)(const char *, const char *);
  static t_fopen$1 r_fopen$1 = 0;
  if(!r_fopen$1) r_fopen$1 = (t_fopen$1)dlsym(RTLD_NEXT, "fopen$1");

  if(memcmp(target, filename, sizeof(target)-1)==0)
    return NULL;

  return r_fopen$1(filename, mode);
}
EOF
}

src >hook.c
src | gcc -shared -fPIC -o hook.so -xc - -l dl

genisoimage -r -J -o cd1.iso "$target"

export LD_PRELOAD=$PWD/hook.so
genisoimage -r -J -o cd2.iso "$target"