#include <signal.h>
#include <sys/wait.h>
#include <sys/ptrace.h>
#include <sys/user.h>
#include <unistd.h>
#include <sched.h>
#include <assert.h>
#include <asm/unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <error.h>
#include <errno.h>
	      
#if defined __x86_64__ || defined __i386__
#define LOOP 10

static pid_t child;      

static void
cleanup (void)
{
  if (child != 0)
    kill (child, SIGKILL);
}

static void
handler_fail (int signo)
{
  cleanup ();

  signal (SIGABRT, SIG_DFL);
  assert (0);
}


int main(int argc, char **argv) {
     int status, j;
     long l;	      
     pid_t pid;

     setbuf (stdout, NULL);
     atexit (cleanup);
     signal (SIGABRT, handler_fail);

     child = fork();
     switch (child) 
     {
	case -1:
		assert(0);
	case 0:  
	  {  l = ptrace(PTRACE_TRACEME, 0, 0, 0);
	     assert(l==0);
	     raise(SIGSTOP);
	     while (1) { 
		l = access(".",R_OK);
		assert(l==0);
	     }	
	     assert(0); //not reached
	   } //end child
	default:
	    break;
         }
    	
 	pid = waitpid(child, &status, 0); 
	assert(pid==child);

        assert(WIFSTOPPED(status));
        assert(WSTOPSIG(status) == SIGSTOP);

	l = ptrace(PTRACE_SYSCALL,child, 0, 0);
	assert(l==0);

       	j = 0;
	while (j < LOOP){

	      pid = waitpid(child, &status, 0);
	      assert(child==pid);
		
	      assert(WIFSTOPPED(status));
	      assert(WSTOPSIG(status) == SIGTRAP);

       	      l = ptrace(PTRACE_SYSCALL, child, 0, 0);
	      assert(l==0);
	      j++;
         } //end loop

	l = ptrace(PTRACE_CONT, child, 0, SIGKILL);
	//if the following statement, always successful
	//l = ptrace(PTRACE_KILL, child, 0,0); 
	if (l < 0) {
   	    error (0, errno,"PTRACE_CONT, pid %ld, retvalue %ld",(long)child,l);
  	    return 1;
	}	
	else
	    assert(l==0);

	pid = waitpid(child, &status, 0);
	assert(child==pid);

	if (WIFEXITED(status) && WTERMSIG(status)!=SIGKILL) 
	      return 1;
	return 0;
} //end main
	      
#else
int main(int argc, char **argv) {
	return 77;
}
#endif