#include <sys/param.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/siginfo.h>
#include <sys/wait.h>
#include <signal.h>
#include <unistd.h>
#include <assert.h>
#include <stdio.h>

int
main(int argc, char **argv)
{
        const int exitval = 5;
        const int sigval = SIGSTOP;
        pid_t child, wpid;
        int status;
        struct ptrace_lwpinfo info = {};

        printf("Before forking process PID=%d\n", getpid());
        assert((child = fork()) != -1);
        if (child == 0) {
                printf("Before calling PT_TRACE_ME from child %d\n", getpid());
                assert(ptrace(PT_TRACE_ME, 0, NULL, 0) != -1);

                printf("Before raising breakpoint from child\n");
		__asm__ __volatile__("int3");
                                                                                                                                                                                              
                printf("Before exiting of the child process\n");
                _exit(exitval);
        }
        printf("Parent process PID=%d, child's PID=%d\n", getpid(), child);

        printf("Before calling waitpid for the child\n");
        wpid = waitpid(child, &status, 0);

        printf("Before calling ptrace(2) with PT_LWPINFO for child\n");
        assert(ptrace(PT_LWPINFO, child, &info, sizeof(info)) != -1);

        printf("Assert that there exists a thread\n");
        assert(info.pl_lwpid > 0);

        printf("Assert that lwp thread %d received event PL_EVENT_SIGNAL\n",
            info.pl_lwpid);
        assert(info.pl_event == PL_EVENT_SIGNAL);

	printf("signo=%#x errno=%#x code=%#x\n", info.pl_siginfo.si_signo, info.pl_siginfo.si_errno, info.pl_siginfo.si_code);

        printf("Before calling ptrace(2) with PT_LWPINFO for child\n");
        assert(ptrace(PT_LWPINFO, child, &info, sizeof(info)) != -1);
                                                                                                                                                                                              
        printf("Assert that there are no more lwp threads in child\n");
        assert(info.pl_lwpid == 0);

        printf("Before resuming the child process where it left off and "
            "without signal to be sent\n");
        assert(ptrace(PT_CONTINUE, child, (void *)1, 0) != -1);

        printf("Before calling waitpid for the child\n");
        wpid = waitpid(child, &status, 0);

        printf("Before calling waitpid for the child\n");
        wpid = waitpid(child, &status, 0);
}