#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define UNCONN_DGRAM_PATH       "/tmp/unconn_dgram.sock"

static void
test_send_unconn_dgram(void)
{
        struct sockaddr_un un;
        int s, n;

        s = socket(AF_LOCAL, SOCK_DGRAM, 0);
        if (s < 0)
                err(1, "send socket failed");

        memset(&un, 0, sizeof(un));
        un.sun_family = AF_LOCAL;
        strlcpy(un.sun_path, UNCONN_DGRAM_PATH, sizeof(un.sun_path));

        n = sendto(s, UNCONN_DGRAM_PATH, sizeof(UNCONN_DGRAM_PATH), 0,
            (const struct sockaddr *)&un, sizeof(un));
        if (n < 0)
                err(1, "sendto failed");
        else if (n != sizeof(UNCONN_DGRAM_PATH))
                err(1, "sendto size mismatch");
}

int
main(void)
{
        struct sockaddr_un un;
        char buf[64];
        pid_t pid;
        int s, n, status;

        s = socket(AF_LOCAL, SOCK_DGRAM, 0);
        if (s < 0)
                err(1, "socket failed");

        memset(&un, 0, sizeof(un));
        un.sun_family = AF_LOCAL;
        strlcpy(un.sun_path, UNCONN_DGRAM_PATH, sizeof(un.sun_path));
        unlink(un.sun_path);

        if (bind(s, (const struct sockaddr *)&un, sizeof(un)) < 0)
                err(1, "bind failed");

        pid = fork();
        if (pid < 0) {
                err(1, "fork failed");
        } else if (pid == 0) {
                close(s);
                test_send_unconn_dgram();
                exit(0);
        }
        waitpid(pid, &status, 0);
        if (!WIFEXITED(status))
                err(1, "child did not exit");
        if (WEXITSTATUS(status) != 0)
                err(WEXITSTATUS(status), "child failed");

        n = read(s, buf, sizeof(buf));
        if (n < 0) {
                err(1, "read failed");
        } else if (n != sizeof(UNCONN_DGRAM_PATH)) {
                warnx("dgram size mismatch");
                abort();
        }
        fprintf(stderr, "%s\n", buf);

        exit(0);
}