/*      $NetBSD: h_mdserv.c,v 1.5 2021/09/16 22:19:11 andvar Exp $      */

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/ioctl.h>

#include <dev/md.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <rump/rump.h>
#include <rump/rump_syscalls.h>

#define MDSIZE (1024*1024)

#define REQUIRE(a, msg) if ((a) != 0) err(1, msg);

static void *
prober(void *arg)
{
        int fd, error;
        char buf[4];
        ssize_t n;

        fd = rump_sys_open(arg, O_RDONLY);
        for (;;) {
                n = rump_sys_read(fd, buf, sizeof(buf));

                switch (n) {
                case 4:
                        error = 0;
                        goto out;

                case -1:
                        if (errno == ENXIO) {
                                usleep(1000);
                                continue;
                        }

                        /* FALLTHROUGH */
                default:
                        error = EPIPE;
                        goto out;
                }
        }
 out:

        error = rump_daemonize_done(error);
        REQUIRE(error, "rump_daemonize_done");

        if (error)
                exit(1);

        return NULL;
}

int
main(int argc, char *argv[])
{
        pthread_t pt;
        struct md_conf md;
        int fd, error;

        if (argc != 2)
                exit(1);

        md.md_addr = calloc(1, MDSIZE);
        md.md_size = MDSIZE;
        md.md_type = MD_UMEM_SERVER;

        error = rump_daemonize_begin();
        REQUIRE(error, "rump_daemonize_begin");

        error = rump_init();
        REQUIRE(error, "rump_init");

        error = rump_init_server("unix://commsock");
        REQUIRE(error, "init server");

        if ((fd = rump_sys_open(argv[1], O_RDWR)) == -1)
                err(1, "open");

        /*
         * Now, configuring the md driver also causes our process
         * to start acting as the worker for the md.  Splitting it
         * into two steps in the driver is not easy, since md is
         * supposed to be unconfigured when the process dies
         * (process may exit between calling ioctl1 and ioctl2).
         * So, start a probe thread which attempts to read the md
         * and declares the md as configured when the read is
         * successful.
         */
        error = pthread_create(&pt, NULL, prober, argv[1]);
        REQUIRE(error, "pthread_create");
        pthread_detach(pt);

        if (rump_sys_ioctl(fd, MD_SETCONF, &md) == -1) {
                rump_daemonize_done(errno);
                exit(1);
        }

        return 0;
}