#!/bin/bash

rm main.so

echo '#define _GNU_SOURCE
#include <dlfcn.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>

void dump(const char* text, int fildes, const void* buf, ssize_t size)
{
  ssize_t i;
  if(size==-1)
  {
    printf("%s(%i)=-1\n\n",text, fildes);
    return;
  }
  printf("%s(%i)=%zu\n  ",text, fildes, size);
  for(i=0;i<size;i++)
    printf("%02X ", ((const char*)buf)[i]);
  printf("\n\n");
}

ssize_t write(int fildes, const void *buf, size_t nbyte)
{
  static ssize_t (*real_write)(int fildes, const void *buf, size_t nbyte) = 0;
  ssize_t result;
  if(!real_write) real_write = dlsym(RTLD_NEXT, "write");
  result = real_write(fildes, buf, nbyte);
  dump("write", fildes, buf, result);
  return result;
}

ssize_t read(int fildes, void *buf, size_t nbyte)
{
  static ssize_t (*real_read)(int fildes, void *buf, size_t nbyte) = 0;
  ssize_t result;
  if(!real_read) real_read = dlsym(RTLD_NEXT, "read");
  result = real_read(fildes, buf, nbyte);
  dump("read", fildes, buf, result);
  return result;
}

int open(const char *filename, int flags, ...)
{
  static int (*real_open)(const char *, int, mode_t) = 0;
  int result;
  va_list ap;
  mode_t mode;

  if (!real_open) real_open = dlsym(RTLD_NEXT, "open");

  va_start(ap, flags);
  mode = va_arg(ap, mode_t);
  va_end(ap);

  result = real_open(filename, flags, mode);

  printf("open(%s)=%i\n\n", filename, result);

  return result;
}
' | gcc -fPIC -shared -Wl,-soname,main.so -o main.so -xc -
LD_PRELOAD=$PWD/main.so putty >out.log