コード例 #1
0
ファイル: libxl_create.c プロジェクト: CPFL/gxen
static int store_libxl_entry(libxl__gc *gc, uint32_t domid,
                             libxl_domain_build_info *b_info)
{
    char *path = NULL;

    path = libxl__xs_libxl_path(gc, domid);
    path = libxl__sprintf(gc, "%s/dm-version", path);
    return libxl__xs_write(gc, XBT_NULL, path, "%s",
        libxl_device_model_version_to_string(b_info->device_model_version));
}
コード例 #2
0
ファイル: libxl_bootloader.c プロジェクト: nypdmax/RT-Xen
static void bootloader_gotptys(libxl__egc *egc, libxl__openpty_state *op)
{
    libxl__bootloader_state *bl = CONTAINER_OF(op, *bl, openpty);
    STATE_AO_GC(bl->ao);
    int rc, r;
    char *const env[] = { "TERM", "vt100", NULL };

    if (bl->openpty.rc) {
        rc = bl->openpty.rc;
        goto out;
    }

    /*
     * We need to present the bootloader's tty as a pty slave that xenconsole
     * can access.  Since the bootloader itself needs a pty slave,
     * we end up with a connection like this:
     *
     * xenconsole -- (slave pty1 master) <-> (master pty2 slave) -- bootloader
     *
     * where we copy characters between the two master fds, as well as
     * listening on the bootloader's fifo for the results.
     */

    char *dom_console_xs_path;
    char dom_console_slave_tty_path[PATH_MAX];
    rc = setup_xenconsoled_pty(egc, bl,
                               &dom_console_slave_tty_path[0],
                               sizeof(dom_console_slave_tty_path));
    if (rc) goto out;

    char *dompath = libxl__xs_get_dompath(gc, bl->domid);
    if (!dompath) {
        rc = ERROR_FAIL;
        goto out;
    }

    dom_console_xs_path = GCSPRINTF("%s/console/tty", dompath);

    rc = libxl__xs_write(gc, XBT_NULL, dom_console_xs_path, "%s",
                         dom_console_slave_tty_path);
    if (rc) {
        LOGE(ERROR,"xs write console path %s := %s failed",
             dom_console_xs_path, dom_console_slave_tty_path);
        rc = ERROR_FAIL;
        goto out;
    }

    bl->deathcheck.what = "stopping bootloader";
    bl->deathcheck.domid = bl->domid;
    bl->deathcheck.callback = bootloader_domaindeath;
    rc = libxl__domaindeathcheck_start(gc, &bl->deathcheck);
    if (rc) goto out;

    if (bl->console_available)
        bl->console_available(egc, bl);

    int bootloader_master = libxl__carefd_fd(bl->ptys[0].master);
    int xenconsole_master = libxl__carefd_fd(bl->ptys[1].master);

    libxl_fd_set_nonblock(CTX, bootloader_master, 1);
    libxl_fd_set_nonblock(CTX, xenconsole_master, 1);

    bl->keystrokes.writefd   = bl->display.readfd   = bootloader_master;
    bl->keystrokes.writewhat = bl->display.readwhat = "bootloader pty";

    bl->keystrokes.readfd   = bl->display.writefd   = xenconsole_master;
    bl->keystrokes.readwhat = bl->display.writewhat = "xenconsole client pty";

    bl->keystrokes.ao = ao;
    bl->keystrokes.maxsz = BOOTLOADER_BUF_OUT;
    bl->keystrokes.copywhat =
        GCSPRINTF("bootloader input for domain %"PRIu32, bl->domid);
    bl->keystrokes.callback =         bootloader_keystrokes_copyfail;
    bl->keystrokes.callback_pollhup = bootloader_keystrokes_copyfail;
    /* pollhup gets called with errnoval==-1 which is not otherwise
     * possible since errnos are nonnegative, so it's unambiguous */
    rc = libxl__datacopier_start(&bl->keystrokes);
    if (rc) goto out;

    bl->display.ao = ao;
    bl->display.maxsz = BOOTLOADER_BUF_IN;
    bl->display.copywhat =
        GCSPRINTF("bootloader output for domain %"PRIu32, bl->domid);
    bl->display.callback =         bootloader_display_copyfail;
    bl->display.callback_pollhup = bootloader_display_copyfail;
    rc = libxl__datacopier_start(&bl->display);
    if (rc) goto out;

    LOG(DEBUG, "executing bootloader: %s", bl->args[0]);
    for (const char **blarg = bl->args;
            *blarg;
            blarg++)
        LOG(DEBUG, "  bootloader arg: %s", *blarg);

    struct termios termattr;

    pid_t pid = libxl__ev_child_fork(gc, &bl->child, bootloader_finished);
    if (pid == -1) {
        rc = ERROR_FAIL;
        goto out;
    }

    if (!pid) {
        /* child */
        r = login_tty(libxl__carefd_fd(bl->ptys[0].slave));
        if (r) {
            LOGE(ERROR, "login_tty failed");
            exit(-1);
        }
        libxl__exec(gc, -1, -1, -1, bl->args[0], (char **) bl->args, env);
        exit(-1);
    }

    /* parent */

    /*
     * On Solaris, the master pty side does not have terminal semantics,
     * so don't try to set any attributes, as it will fail.
     */
#if !defined(__sun__)
    tcgetattr(bootloader_master, &termattr);
    cfmakeraw(&termattr);
    tcsetattr(bootloader_master, TCSANOW, &termattr);
#endif

    return;

out:
    bootloader_callback(egc, bl, rc);
}
コード例 #3
0
ファイル: libxl_dm.c プロジェクト: jsgf/xen
void libxl__spawn_stub_dm(libxl__egc *egc, libxl__stub_dm_spawn_state *sdss)
{
    STATE_AO_GC(sdss->dm.spawn.ao);
    libxl_ctx *ctx = libxl__gc_owner(gc);
    int ret;
    libxl_device_vfb *vfb;
    libxl_device_vkb *vkb;
    char **args;
    struct xs_permissions perm[2];
    xs_transaction_t t;

    /* convenience aliases */
    libxl_domain_config *const dm_config = &sdss->dm_config;
    libxl_domain_config *const guest_config = sdss->dm.guest_config;
    const int guest_domid = sdss->dm.guest_domid;
    libxl__domain_build_state *const d_state = sdss->dm.build_state;
    libxl__domain_build_state *const stubdom_state = &sdss->dm_state;

    if (guest_config->b_info.device_model_version !=
        LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL) {
        ret = ERROR_INVAL;
        goto out;
    }

    sdss->pvqemu.guest_domid = 0;

    libxl_domain_create_info_init(&dm_config->c_info);
    dm_config->c_info.type = LIBXL_DOMAIN_TYPE_PV;
    dm_config->c_info.name = libxl__stub_dm_name(gc,
                                    libxl__domid_to_name(gc, guest_domid));
    dm_config->c_info.ssidref = guest_config->b_info.device_model_ssidref;

    libxl_uuid_generate(&dm_config->c_info.uuid);

    libxl_domain_build_info_init(&dm_config->b_info);
    libxl_domain_build_info_init_type(&dm_config->b_info, LIBXL_DOMAIN_TYPE_PV);

    dm_config->b_info.max_vcpus = 1;
    dm_config->b_info.max_memkb = 32 * 1024;
    dm_config->b_info.target_memkb = dm_config->b_info.max_memkb;

    dm_config->b_info.u.pv.features = "";

    dm_config->b_info.device_model_version =
        guest_config->b_info.device_model_version;
    dm_config->b_info.device_model =
        guest_config->b_info.device_model;
    dm_config->b_info.extra = guest_config->b_info.extra;
    dm_config->b_info.extra_pv = guest_config->b_info.extra_pv;
    dm_config->b_info.extra_hvm = guest_config->b_info.extra_hvm;

    dm_config->disks = guest_config->disks;
    dm_config->num_disks = guest_config->num_disks;

    libxl__dm_vifs_from_hvm_guest_config(gc, guest_config, dm_config);

    dm_config->c_info.run_hotplug_scripts =
        guest_config->c_info.run_hotplug_scripts;

    ret = libxl__domain_create_info_setdefault(gc, &dm_config->c_info);
    if (ret) goto out;
    ret = libxl__domain_build_info_setdefault(gc, &dm_config->b_info);
    if (ret) goto out;

    GCNEW(vfb);
    GCNEW(vkb);
    libxl__vfb_and_vkb_from_hvm_guest_config(gc, guest_config, vfb, vkb);
    dm_config->vfbs = vfb;
    dm_config->num_vfbs = 1;
    dm_config->vkbs = vkb;
    dm_config->num_vkbs = 1;

    stubdom_state->pv_kernel.path
        = libxl__abs_path(gc, "ioemu-stubdom.gz", libxl__xenfirmwaredir_path());
    stubdom_state->pv_cmdline = libxl__sprintf(gc, " -d %d", guest_domid);
    stubdom_state->pv_ramdisk.path = "";

    /* fixme: this function can leak the stubdom if it fails */
    ret = libxl__domain_make(gc, &dm_config->c_info, &sdss->pvqemu.guest_domid);
    if (ret)
        goto out;
    uint32_t dm_domid = sdss->pvqemu.guest_domid;
    ret = libxl__domain_build(gc, dm_config, dm_domid, stubdom_state);
    if (ret)
        goto out;

    args = libxl__build_device_model_args(gc, "stubdom-dm", guest_domid,
                                          guest_config, d_state);
    if (!args) {
        ret = ERROR_FAIL;
        goto out;
    }

    libxl__write_stub_dmargs(gc, dm_domid, guest_domid, args);
    libxl__xs_write(gc, XBT_NULL,
                   libxl__sprintf(gc, "%s/image/device-model-domid",
                                  libxl__xs_get_dompath(gc, guest_domid)),
                   "%d", dm_domid);
    libxl__xs_write(gc, XBT_NULL,
                   libxl__sprintf(gc, "%s/target",
                                  libxl__xs_get_dompath(gc, dm_domid)),
                   "%d", guest_domid);
    ret = xc_domain_set_target(ctx->xch, dm_domid, guest_domid);
    if (ret<0) {
        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
                         "setting target domain %d -> %d",
                         dm_domid, guest_domid);
        ret = ERROR_FAIL;
        goto out;
    }
    xs_set_target(ctx->xsh, dm_domid, guest_domid);

    perm[0].id = dm_domid;
    perm[0].perms = XS_PERM_NONE;
    perm[1].id = guest_domid;
    perm[1].perms = XS_PERM_READ;
retry_transaction:
    t = xs_transaction_start(ctx->xsh);
    xs_mkdir(ctx->xsh, t,
        libxl__sprintf(gc, "/local/domain/0/device-model/%d", guest_domid));
    xs_set_permissions(ctx->xsh, t,
        libxl__sprintf(gc, "/local/domain/0/device-model/%d", guest_domid),
                       perm, ARRAY_SIZE(perm));
    if (!xs_transaction_end(ctx->xsh, t, 0))
        if (errno == EAGAIN)
            goto retry_transaction;

    libxl__multidev_begin(ao, &sdss->multidev);
    sdss->multidev.callback = spawn_stub_launch_dm;
    libxl__add_disks(egc, ao, dm_domid, dm_config, &sdss->multidev);
    libxl__multidev_prepared(egc, &sdss->multidev, 0);

    return;

out:
    assert(ret);
    spawn_stubdom_pvqemu_cb(egc, &sdss->pvqemu, ret);
}
コード例 #4
0
ファイル: libxl_dm.c プロジェクト: jsgf/xen
void libxl__spawn_local_dm(libxl__egc *egc, libxl__dm_spawn_state *dmss)
{
    /* convenience aliases */
    const int domid = dmss->guest_domid;
    libxl__domain_build_state *const state = dmss->build_state;
    libxl__spawn_state *const spawn = &dmss->spawn;

    STATE_AO_GC(dmss->spawn.ao);

    libxl_ctx *ctx = CTX;
    libxl_domain_config *guest_config = dmss->guest_config;
    const libxl_domain_create_info *c_info = &guest_config->c_info;
    const libxl_domain_build_info *b_info = &guest_config->b_info;
    const libxl_vnc_info *vnc = libxl__dm_vnc(guest_config);
    char *path, *logfile;
    int logfile_w, null;
    int rc;
    char **args, **arg;
    xs_transaction_t t;
    char *vm_path;
    char **pass_stuff;
    const char *dm;

    if (libxl_defbool_val(b_info->device_model_stubdomain)) {
        abort();
    }

    dm = libxl__domain_device_model(gc, b_info);
    if (!dm) {
        rc = ERROR_FAIL;
        goto out;
    }
    if (access(dm, X_OK) < 0) {
        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
                         "device model %s is not executable", dm);
        rc = ERROR_FAIL;
        goto out;
    }
    args = libxl__build_device_model_args(gc, dm, domid, guest_config, state);
    if (!args) {
        rc = ERROR_FAIL;
        goto out;
    }

    if (b_info->type == LIBXL_DOMAIN_TYPE_HVM) {
        path = xs_get_domain_path(ctx->xsh, domid);
        libxl__xs_write(gc, XBT_NULL,
                        libxl__sprintf(gc, "%s/hvmloader/bios", path),
                        "%s", libxl_bios_type_to_string(b_info->u.hvm.bios));
        /* Disable relocating memory to make the MMIO hole larger
         * unless we're running qemu-traditional */
        libxl__xs_write(gc, XBT_NULL,
                        libxl__sprintf(gc,
                                       "%s/hvmloader/allow-memory-relocate",
                                       path),
                        "%d",
                        b_info->device_model_version==LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL);
        free(path);
    }

    path = libxl__sprintf(gc, "/local/domain/0/device-model/%d", domid);
    xs_mkdir(ctx->xsh, XBT_NULL, path);

    if (b_info->type == LIBXL_DOMAIN_TYPE_HVM &&
        b_info->device_model_version
        == LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL)
        libxl__xs_write(gc, XBT_NULL, libxl__sprintf(gc, "%s/disable_pf", path),
                    "%d", !libxl_defbool_val(b_info->u.hvm.xen_platform_pci));

    libxl_create_logfile(ctx,
                         libxl__sprintf(gc, "qemu-dm-%s", c_info->name),
                         &logfile);
    logfile_w = open(logfile, O_WRONLY|O_CREAT|O_APPEND, 0644);
    free(logfile);
    null = open("/dev/null", O_RDONLY);

    const char *dom_path = libxl__xs_get_dompath(gc, domid);
    spawn->pidpath = GCSPRINTF("%s/%s", dom_path, "image/device-model-pid");

    if (vnc && vnc->passwd) {
        /* This xenstore key will only be used by qemu-xen-traditionnal.
         * The code to supply vncpasswd to qemu-xen is later. */
retry_transaction:
        /* Find uuid and the write the vnc password to xenstore for qemu. */
        t = xs_transaction_start(ctx->xsh);
        vm_path = libxl__xs_read(gc,t,libxl__sprintf(gc, "%s/vm", dom_path));
        if (vm_path) {
            /* Now write the vncpassword into it. */
            pass_stuff = libxl__calloc(gc, 3, sizeof(char *));
            pass_stuff[0] = "vncpasswd";
            pass_stuff[1] = vnc->passwd;
            libxl__xs_writev(gc,t,vm_path,pass_stuff);
            if (!xs_transaction_end(ctx->xsh, t, 0))
                if (errno == EAGAIN)
                    goto retry_transaction;
        }
    }

    LIBXL__LOG(CTX, XTL_DEBUG, "Spawning device-model %s with arguments:", dm);
    for (arg = args; *arg; arg++)
        LIBXL__LOG(CTX, XTL_DEBUG, "  %s", *arg);

    spawn->what = GCSPRINTF("domain %d device model", domid);
    spawn->xspath = GCSPRINTF("/local/domain/0/device-model/%d/state", domid);
    spawn->timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000;
    spawn->pidpath = GCSPRINTF("%s/image/device-model-pid", dom_path);
    spawn->midproc_cb = libxl__spawn_record_pid;
    spawn->confirm_cb = device_model_confirm;
    spawn->failure_cb = device_model_startup_failed;
    spawn->detached_cb = device_model_detached;

    rc = libxl__spawn_spawn(egc, spawn);
    if (rc < 0)
        goto out_close;
    if (!rc) { /* inner child */
        setsid();
        libxl__exec(gc, null, logfile_w, logfile_w, dm, args, NULL);
    }

    rc = 0;

out_close:
    close(null);
    close(logfile_w);
out:
    if (rc)
        device_model_spawn_outcome(egc, dmss, rc);
}
コード例 #5
0
int libxl_run_bootloader(libxl_ctx *ctx,
                         libxl_domain_build_info *info,
                         libxl_device_disk *disk,
                         uint32_t domid)
{
    libxl__gc gc = LIBXL_INIT_GC(ctx);
    int ret, rc = 0;
    char *fifo = NULL;
    char *diskpath = NULL;
    char **args = NULL;

    char tempdir_template[] = "/var/run/libxl/bl.XXXXXX";
    char *tempdir;

    char *dom_console_xs_path;
    char dom_console_slave_tty_path[PATH_MAX];

    int xenconsoled_fd = -1, xenconsoled_slave = -1;
    int bootloader_fd = -1, fifo_fd = -1;

    int blrc;
    pid_t pid;
    char *blout;

    struct stat st_buf;

    if (info->hvm || !info->u.pv.bootloader)
        goto out;

    rc = ERROR_INVAL;
    if (!disk)
        goto out;

    rc = ERROR_FAIL;
    ret = mkdir("/var/run/libxl/", S_IRWXU);
    if (ret < 0 && errno != EEXIST)
        goto out;

    ret = stat("/var/run/libxl/", &st_buf);
    if (ret < 0)
        goto out;

    if (!S_ISDIR(st_buf.st_mode))
        goto out;

    tempdir = mkdtemp(tempdir_template);
    if (tempdir == NULL)
        goto out;

    ret = asprintf(&fifo, "%s/fifo", tempdir);
    if (ret < 0) {
        fifo = NULL;
        goto out_close;
    }

    ret = mkfifo(fifo, 0600);
    if (ret < 0) {
        goto out_close;
    }

    diskpath = libxl_device_disk_local_attach(ctx, disk);
    if (!diskpath) {
        goto out_close;
    }

    args = make_bootloader_args(&gc, info, domid, fifo, diskpath);
    if (args == NULL) {
        rc = ERROR_NOMEM;
        goto out_close;
    }

    /*
     * We need to present the bootloader's tty as a pty slave that xenconsole
     * can access.  Since the bootloader itself needs a pty slave,
     * we end up with a connection like this:
     *
     * xenconsole -- (slave pty1 master) <-> (master pty2 slave) -- bootloader
     *
     * where we copy characters between the two master fds, as well as
     * listening on the bootloader's fifo for the results.
     */
    ret = open_xenconsoled_pty(&xenconsoled_fd, &xenconsoled_slave,
                               &dom_console_slave_tty_path[0],
                               sizeof(dom_console_slave_tty_path));
    if (ret < 0) {
        goto out_close;
    }

    dom_console_xs_path = libxl__sprintf(&gc, "%s/console/tty", libxl__xs_get_dompath(&gc, domid));
    libxl__xs_write(&gc, XBT_NULL, dom_console_xs_path, "%s", dom_console_slave_tty_path);

    pid = fork_exec_bootloader(&bootloader_fd, info->u.pv.bootloader, args);
    if (pid < 0) {
        goto out_close;
    }

    while (1) {
        fifo_fd = open(fifo, O_RDONLY);
        if (fifo_fd > -1)
            break;

        if (errno == EINTR)
            continue;

        goto out_close;
    }

    fcntl(fifo_fd, F_SETFL, O_NDELAY);

    blout = bootloader_interact(&gc, xenconsoled_fd, bootloader_fd, fifo_fd);
    if (blout == NULL) {
        goto out_close;
    }

    pid = waitpid(pid, &blrc, 0);
    if (pid == -1 || (pid > 0 && WIFEXITED(blrc) && WEXITSTATUS(blrc) != 0)) {
        goto out_close;
    }

    parse_bootloader_result(ctx, info, blout);

    rc = 0;
out_close:
    if (diskpath) {
        libxl_device_disk_local_detach(ctx, disk);
        free(diskpath);
    }
    if (fifo_fd > -1)
        close(fifo_fd);
    if (bootloader_fd > -1)
        close(bootloader_fd);
    if (xenconsoled_fd > -1)
        close(xenconsoled_fd);
    if (xenconsoled_slave > -1)
        close(xenconsoled_slave);

    if (fifo) {
        unlink(fifo);
        free(fifo);
    }

    rmdir(tempdir);

    free(args);

out:
    libxl__free_all(&gc);
    return rc;
}
コード例 #6
0
ファイル: libxl_dm.c プロジェクト: changliwei/suse_xen
int libxl__create_device_model(libxl_ctx *ctx,
                              libxl_device_model_info *info,
                              libxl_device_disk *disks, int num_disks,
                              libxl_device_nic *vifs, int num_vifs,
                              libxl__device_model_starting **starting_r)
{
    libxl__gc gc = LIBXL_INIT_GC(ctx);
    char *path, *logfile;
    int logfile_w, null;
    int rc;
    char **args;
    libxl__device_model_starting buf_starting, *p;
    xs_transaction_t t; 
    char *vm_path;
    char **pass_stuff;

    if (strstr(info->device_model, "stubdom-dm")) {
        libxl_device_vfb vfb;
        libxl_device_vkb vkb;

        libxl_vfb_and_vkb_from_device_model_info(ctx, info, &vfb, &vkb);
        rc = libxl_create_stubdom(ctx, info, disks, num_disks, vifs, num_vifs, &vfb, &vkb, starting_r);
        goto out;
    }

    args = libxl_build_device_model_args(&gc, info, vifs, num_vifs);
    if (!args) {
        rc = ERROR_FAIL;
        goto out;
    }

    path = libxl__sprintf(&gc, "/local/domain/0/device-model/%d", info->domid);
    xs_mkdir(ctx->xsh, XBT_NULL, path);
    libxl__xs_write(&gc, XBT_NULL, libxl__sprintf(&gc, "%s/disable_pf", path), "%d", !info->xen_platform_pci);

    libxl_create_logfile(ctx, libxl__sprintf(&gc, "qemu-dm-%s", info->dom_name), &logfile);
    logfile_w = open(logfile, O_WRONLY|O_CREAT, 0644);
    free(logfile);
    null = open("/dev/null", O_RDONLY);

    if (starting_r) {
        rc = ERROR_NOMEM;
        *starting_r = calloc(sizeof(libxl__device_model_starting), 1);
        if (!*starting_r)
            goto out_close;
        p = *starting_r;
        p->for_spawn = calloc(sizeof(libxl__spawn_starting), 1);
    } else {
        p = &buf_starting;
        p->for_spawn = NULL;
    }

    p->domid = info->domid;
    p->dom_path = libxl__xs_get_dompath(&gc, info->domid);
    if (!p->dom_path) {
        rc = ERROR_FAIL;
        goto out_close;
    }

    if (info->vncpasswd) {
retry_transaction:
        /* Find uuid and the write the vnc password to xenstore for qemu. */
        t = xs_transaction_start(ctx->xsh);
        vm_path = libxl__xs_read(&gc,t,libxl__sprintf(&gc, "%s/vm", p->dom_path));
        if (vm_path) {
            /* Now write the vncpassword into it. */
            pass_stuff = libxl__calloc(&gc, 3, sizeof(char *));
            pass_stuff[0] = "vncpasswd";
            pass_stuff[1] = info->vncpasswd;
            libxl__xs_writev(&gc,t,vm_path,pass_stuff);
            if (!xs_transaction_end(ctx->xsh, t, 0))
                if (errno == EAGAIN)
                    goto retry_transaction;
        }
    }

    rc = libxl__spawn_spawn(ctx, p, "device model", dm_xenstore_record_pid);
    if (rc < 0)
        goto out_close;
    if (!rc) { /* inner child */
        setsid();
        libxl__exec(null, logfile_w, logfile_w,
                   libxl__abs_path(&gc, info->device_model, libxl_libexec_path()),
                   args);
    }

    rc = 0;

out_close:
    close(null);
    close(logfile_w);
    free(args);
out:
    libxl__free_all(&gc);
    return rc;
}
コード例 #7
0
ファイル: libxl_dm.c プロジェクト: changliwei/suse_xen
static int libxl_create_stubdom(libxl_ctx *ctx,
                                libxl_device_model_info *info,
                                libxl_device_disk *disks, int num_disks,
                                libxl_device_nic *vifs, int num_vifs,
                                libxl_device_vfb *vfb,
                                libxl_device_vkb *vkb,
                                libxl__device_model_starting **starting_r)
{
    libxl__gc gc = LIBXL_INIT_GC(ctx);
    int i, num_console = STUBDOM_SPECIAL_CONSOLES, ret;
    libxl_device_console *console;
    libxl_domain_create_info c_info;
    libxl_domain_build_info b_info;
    libxl_domain_build_state state;
    uint32_t domid;
    char **args;
    struct xs_permissions perm[2];
    xs_transaction_t t;
    libxl__device_model_starting *dm_starting = 0;

    args = libxl_build_device_model_args(&gc, info, vifs, num_vifs);
    if (!args) {
        ret = ERROR_FAIL;
        goto out;
    }

    memset(&c_info, 0x00, sizeof(libxl_domain_create_info));
    c_info.hvm = 0;
    c_info.name = libxl__sprintf(&gc, "%s-dm", libxl__domid_to_name(&gc, info->domid));

    libxl_uuid_copy(&c_info.uuid, &info->uuid);

    memset(&b_info, 0x00, sizeof(libxl_domain_build_info));
    b_info.max_vcpus = 1;
    b_info.max_memkb = 32 * 1024;
    b_info.target_memkb = b_info.max_memkb;
    b_info.kernel.path = libxl__abs_path(&gc, "ioemu-stubdom.gz", libxl_xenfirmwaredir_path());
    b_info.u.pv.cmdline = libxl__sprintf(&gc, " -d %d", info->domid);
    b_info.u.pv.ramdisk.path = "";
    b_info.u.pv.features = "";
    b_info.hvm = 0;

    /* fixme: this function can leak the stubdom if it fails */

    ret = libxl__domain_make(ctx, &c_info, &domid);
    if (ret)
        goto out_free;
    ret = libxl__domain_build(ctx, &b_info, domid, &state);
    if (ret)
        goto out_free;

    libxl_write_dmargs(ctx, domid, info->domid, args);
    libxl__xs_write(&gc, XBT_NULL,
                   libxl__sprintf(&gc, "%s/image/device-model-domid", libxl__xs_get_dompath(&gc, info->domid)),
                   "%d", domid);
    libxl__xs_write(&gc, XBT_NULL,
                   libxl__sprintf(&gc, "%s/target", libxl__xs_get_dompath(&gc, domid)),
                   "%d", info->domid);
    ret = xc_domain_set_target(ctx->xch, domid, info->domid);
    if (ret<0) {
        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "setting target domain %d -> %d", domid, info->domid);
        ret = ERROR_FAIL;
        goto out_free;
    }
    xs_set_target(ctx->xsh, domid, info->domid);

    perm[0].id = domid;
    perm[0].perms = XS_PERM_NONE;
    perm[1].id = info->domid;
    perm[1].perms = XS_PERM_READ;
retry_transaction:
    t = xs_transaction_start(ctx->xsh);
    xs_mkdir(ctx->xsh, t, libxl__sprintf(&gc, "/local/domain/0/device-model/%d", info->domid));
    xs_set_permissions(ctx->xsh, t, libxl__sprintf(&gc, "/local/domain/0/device-model/%d", info->domid), perm, ARRAY_SIZE(perm));
    xs_mkdir(ctx->xsh, t, libxl__sprintf(&gc, "/local/domain/%d/device/vfs", domid));
    xs_set_permissions(ctx->xsh, t, libxl__sprintf(&gc, "/local/domain/%d/device/vfs",domid), perm, ARRAY_SIZE(perm));
    if (!xs_transaction_end(ctx->xsh, t, 0))
        if (errno == EAGAIN)
            goto retry_transaction;

    for (i = 0; i < num_disks; i++) {
        disks[i].domid = domid;
        ret = libxl_device_disk_add(ctx, domid, &disks[i]);
        if (ret)
            goto out_free;
    }
    for (i = 0; i < num_vifs; i++) {
        vifs[i].domid = domid;
        ret = libxl_device_nic_add(ctx, domid, &vifs[i]);
        if (ret)
            goto out_free;
    }
    vfb->domid = domid;
    ret = libxl_device_vfb_add(ctx, domid, vfb);
    if (ret)
        goto out_free;
    vkb->domid = domid;
    ret = libxl_device_vkb_add(ctx, domid, vkb);
    if (ret)
        goto out_free;

    if (info->serial)
        num_console++;

    console = libxl__calloc(&gc, num_console, sizeof(libxl_device_console));
    if (!console) {
        ret = ERROR_NOMEM;
        goto out_free;
    }

    for (i = 0; i < num_console; i++) {
        console[i].devid = i;
        console[i].consback = LIBXL_CONSBACK_IOEMU;
        console[i].domid = domid;
        /* STUBDOM_CONSOLE_LOGGING (console 0) is for minios logging
         * STUBDOM_CONSOLE_SAVE (console 1) is for writing the save file
         * STUBDOM_CONSOLE_RESTORE (console 2) is for reading the save file
         */
        switch (i) {
            char *filename;
            char *name;
            case STUBDOM_CONSOLE_LOGGING:
                name = libxl__sprintf(&gc, "qemu-dm-%s", libxl_domid_to_name(ctx, info->domid));
                libxl_create_logfile(ctx, name, &filename);
                console[i].output = libxl__sprintf(&gc, "file:%s", filename);
                console[i].build_state = &state;
                free(filename);
                break;
            case STUBDOM_CONSOLE_SAVE:
                console[i].output = libxl__sprintf(&gc, "file:"SAVEFILE".%d", info->domid);
                break;
            case STUBDOM_CONSOLE_RESTORE:
                if (info->saved_state)
                    console[i].output = libxl__sprintf(&gc, "pipe:%s", info->saved_state);
                break;
            default:
                console[i].output = "pty";
                break;
        }
        ret = libxl_device_console_add(ctx, domid, &console[i]);
        if (ret)
            goto out_free;
    }
    if (libxl__create_xenpv_qemu(ctx, domid, vfb, &dm_starting) < 0) {
        ret = ERROR_FAIL;
        goto out_free;
    }
    if (libxl__confirm_device_model_startup(ctx, dm_starting) < 0) {
        ret = ERROR_FAIL;
        goto out_free;
    }

    libxl_domain_unpause(ctx, domid);

    if (starting_r) {
        *starting_r = calloc(sizeof(libxl__device_model_starting), 1);
        (*starting_r)->domid = info->domid;
        (*starting_r)->dom_path = libxl__xs_get_dompath(&gc, info->domid);
        (*starting_r)->for_spawn = NULL;
    }

    ret = 0;

out_free:
    free(args);
out:
    libxl__free_all(&gc);
    return ret;
}