#include <sys/types.h>
#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int stop_received;
int exit_received;
int cont_received;

void
job_handler(int sig, siginfo_t *si, void *ctx)
{
        int status;
        int ret;

        if (si->si_code == CLD_STOPPED) {
                printf("%d: stop received\n", si->si_pid);
                stop_received = 1;
                kill(si->si_pid, SIGCONT);
        } else if (si->si_code == CLD_EXITED) {
                printf("%d: exit received\n", si->si_pid);
                ret = waitpid(si->si_pid, &status, 0);
                if (ret == -1)
                        errx(1, "waitpid");
                if (!WIFEXITED(status))
                        errx(1, "!WIFEXITED(status)");
                exit_received = 1;
        } else if (si->si_code == CLD_CONTINUED) {
                printf("%d: cont received\n", si->si_pid);
                cont_received = 1;
        }
}

void
job_control_test(void)
{
        struct sigaction sa;
        pid_t pid;
        int count = 10;

        sigemptyset(&sa.sa_mask);
        sa.sa_flags = SA_SIGINFO;
        sa.sa_sigaction = job_handler;
        sigaction(SIGCHLD, &sa, NULL);
        stop_received = 0;
        cont_received = 0;
        exit_received = 0;
        fflush(stdout);
        pid = fork();
        if (pid == 0) {
                printf("child %d\n", getpid());
                kill(getpid(), SIGSTOP);
                sleep(2);
                exit(1);
        }

        while (!(cont_received && stop_received && exit_received)) {
                sleep(1);
                if (--count == 0)
                        break;
        }
        if (!(cont_received && stop_received && exit_received))
                errx(1, "job signals lost");

        printf("job control test OK.\n");
}

void
rtsig_handler(int sig, siginfo_t *si, void *ctx)
{
}

int
main()
{
        struct sigaction sa;
        sigset_t set;
        union sigval val;

        /* test job control with empty signal queue */
        job_control_test();

        /* now full fill signal queue in kernel */
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = SA_SIGINFO;
        sa.sa_sigaction = rtsig_handler;
        sigaction(SIGRTMIN, &sa, NULL);
        sigemptyset(&set);
        sigaddset(&set, SIGRTMIN);
        sigprocmask(SIG_BLOCK, &set, NULL);
        val.sival_int = 1;
        while (sigqueue(getpid(), SIGRTMIN, val))
                ;

        /* signal queue is fully filled, test the job control again. */
        job_control_test();
        return (0);
}