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

int main(int argc, char *argv[])
{   pid_t traced_process;
    struct user_regs_struct regs;
    long ins;

    if(argc != 2) {
        printf("Usage: %s <pid to be traced>\n", argv[0], argv[1]);
        exit(1);
    }

    traced_process = atoi(argv[1]);
    ptrace(PTRACE_ATTACH, traced_process, NULL, NULL);
    wait(NULL);
    ptrace(PTRACE_GETREGS, traced_process, NULL, &regs);
    ins = ptrace(PTRACE_PEEKTEXT, traced_process, regs.eip, NULL);
    printf("EIP: %lx Instruction executed: %lx\n", regs.eip, ins);
    ptrace(PTRACE_DETACH, traced_process, NULL, NULL);

    return 0;
}