#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/ptrace.h>
#include<sys/user.h>
#include<sys/wait.h>

#define DONT_CARE 0

int stats;
struct user_regs_struct regs;

void continue_execution(pid_t pid)
{
  ptrace(PTRACE_CONT, pid, DONT_CARE, DONT_CARE);
  waitpid(pid, &stats, 0);
  return;
}

void print_rax(pid_t pid)
{
  ptrace(PTRACE_GETREGS, pid, DONT_CARE, &regs);
  printf("rax = %llu\n", regs.rax);
  return;
}

void step(pid_t pid)
{
  ptrace(PTRACE_SINGLESTEP, pid, DONT_CARE, DONT_CARE);
  waitpid(pid, &stats, 0);
  return;
}

int main()
{
  printf("procces is run ");
  pid_t pid;
  pid = fork();
  if (pid==0)
  {
    printf(" -- child\n");
    ptrace(PTRACE_TRACEME, 0, 0, 0);
    execl("./testee", "testee", NULL);
    printf("____AFTER_TRACE_CHILD____\n");
  }
  else if(pid > 0)
  {
    char buff;
    printf(" -- parrent\n");
    continue_execution(pid); // to start app
    continue_execution(pid);
    if (stats & SIGTRAP)
    {
      printf("--BREAKPOINT--\n");
      while (stats != 0)
      {
        read(0, &buff, 1);
        print_rax(pid);
        step(pid);
      }
    }

  printf("____PROCESS_WAS_TERMINATED____\n");
  }
  return 0;
}