//----------------------------------------------------------------
//	mytracer.cpp
//
//	Here is an experimental 'prototype' for a debugging tool, 
//	based on the Linux 'ptrace()' programming interface.
//
//	programmer: ALLAN CRUSE
//	written on: 13 NOV 2003
//----------------------------------------------------------------

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

char *regname[ 17 ] = { "EBX", "ECX", "EDX", "ESI", "EDI", "EBP", "EAX",
	"DS", "ES", "FS", "GS", "---", "EIP", "CS", "EFL", "ESP", "SS" };

int main( int argc, char **argv )
{
	int	pid = fork();
	if ( !pid ) 
		{
		ptrace( PTRACE_TRACEME, 0, 0, 0 );
		execve( argv[1], NULL, NULL );
		exit(1);
		}

	int	status = 0;
	wait( &status );

	for (int step = 0; step < 8; step++)
		{
		unsigned int	address;
		for (int i = 0; i < 17; i++)
			{
			address = ptrace( PTRACE_PEEKUSER, pid, i<<2 ); 
			printf( "\n%02X: %08X ", i<<2, address );
			printf( " (%s) ", regname[ i ] );
			}
		printf( "\n" );
		getchar();
	
		ptrace( PTRACE_SINGLESTEP, pid, 0, 0 );
		status = 0;
		wait( &status );
		}

	ptrace( PTRACE_CONT, pid );	
	status = 0;
	wait( &status );
	
	printf( "\nparent-process \'%s\' is quitting\n", argv[0] );
}