ui/dbus: add chardev backend & interface

Add a new chardev backend which allows D-Bus client to handle the
chardev stream & events.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 296 insertions, 0 deletions

diff --git a/ui/dbus-chardev.c b/ui/dbus-chardev.c
new file mode 100644
index 0000000000..940ef937cd
--- /dev/null
+++ b/ui/dbus-chardev.c
@@ -0,0 +1,296 @@
+/*
+ * QEMU DBus display
+ *
+ * Copyright (c) 2021 Marc-André Lureau <marcandre.lureau@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu/osdep.h"
+#include "trace.h"
+#include "qapi/error.h"
+#include "qemu/config-file.h"
+#include "qemu/option.h"
+
+#include <gio/gunixfdlist.h>
+
+#include "dbus.h"
+
+static char *
+dbus_display_chardev_path(DBusChardev *chr)
+{
+    return g_strdup_printf(DBUS_DISPLAY1_ROOT "/Chardev_%s",
+                           CHARDEV(chr)->label);
+}
+
+static void
+dbus_display_chardev_export(DBusDisplay *dpy, DBusChardev *chr)
+{
+    g_autoptr(GDBusObjectSkeleton) sk = NULL;
+    g_autofree char *path = dbus_display_chardev_path(chr);
+
+    if (chr->exported) {
+        return;
+    }
+
+    sk = g_dbus_object_skeleton_new(path);
+    g_dbus_object_skeleton_add_interface(
+        sk, G_DBUS_INTERFACE_SKELETON(chr->iface));
+    g_dbus_object_manager_server_export(dpy->server, sk);
+    chr->exported = true;
+}
+
+static void
+dbus_display_chardev_unexport(DBusDisplay *dpy, DBusChardev *chr)
+{
+    g_autofree char *path = dbus_display_chardev_path(chr);
+
+    if (!chr->exported) {
+        return;
+    }
+
+    g_dbus_object_manager_server_unexport(dpy->server, path);
+    chr->exported = false;
+}
+
+static int
+dbus_display_chardev_foreach(Object *obj, void *data)
+{
+    DBusDisplay *dpy = DBUS_DISPLAY(data);
+
+    if (!CHARDEV_IS_DBUS(obj)) {
+        return 0;
+    }
+
+    dbus_display_chardev_export(dpy, DBUS_CHARDEV(obj));
+
+    return 0;
+}
+
+static void
+dbus_display_on_notify(Notifier *notifier, void *data)
+{
+    DBusDisplay *dpy = container_of(notifier, DBusDisplay, notifier);
+    DBusDisplayEvent *event = data;
+
+    switch (event->type) {
+    case DBUS_DISPLAY_CHARDEV_OPEN:
+        dbus_display_chardev_export(dpy, event->chardev);
+        break;
+    case DBUS_DISPLAY_CHARDEV_CLOSE:
+        dbus_display_chardev_unexport(dpy, event->chardev);
+        break;
+    }
+}
+
+void
+dbus_chardev_init(DBusDisplay *dpy)
+{
+    dpy->notifier.notify = dbus_display_on_notify;
+    dbus_display_notifier_add(&dpy->notifier);
+
+    object_child_foreach(container_get(object_get_root(), "/chardevs"),
+                         dbus_display_chardev_foreach, dpy);
+}
+
+static gboolean
+dbus_chr_register(
+    DBusChardev *dc,
+    GDBusMethodInvocation *invocation,
+    GUnixFDList *fd_list,
+    GVariant *arg_stream,
+    QemuDBusDisplay1Chardev *object)
+{
+    g_autoptr(GError) err = NULL;
+    int fd;
+
+    fd = g_unix_fd_list_get(fd_list, g_variant_get_handle(arg_stream), &err);
+    if (err) {
+        g_dbus_method_invocation_return_error(
+            invocation,
+            DBUS_DISPLAY_ERROR,
+            DBUS_DISPLAY_ERROR_FAILED,
+            "Couldn't get peer FD: %s", err->message);
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    if (qemu_chr_add_client(CHARDEV(dc), fd) < 0) {
+        g_dbus_method_invocation_return_error(invocation,
+                                              DBUS_DISPLAY_ERROR,
+                                              DBUS_DISPLAY_ERROR_FAILED,
+                                              "Couldn't register FD!");
+        close(fd);
+        return DBUS_METHOD_INVOCATION_HANDLED;
+    }
+
+    g_object_set(dc->iface,
+                 "owner", g_dbus_method_invocation_get_sender(invocation),
+                 NULL);
+
+    qemu_dbus_display1_chardev_complete_register(object, invocation, NULL);
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static gboolean
+dbus_chr_send_break(
+    DBusChardev *dc,
+    GDBusMethodInvocation *invocation,
+    QemuDBusDisplay1Chardev *object)
+{
+    qemu_chr_be_event(CHARDEV(dc), CHR_EVENT_BREAK);
+
+    qemu_dbus_display1_chardev_complete_send_break(object, invocation);
+    return DBUS_METHOD_INVOCATION_HANDLED;
+}
+
+static void
+dbus_chr_open(Chardev *chr, ChardevBackend *backend,
+              bool *be_opened, Error **errp)
+{
+    ERRP_GUARD();
+
+    DBusChardev *dc = DBUS_CHARDEV(chr);
+    DBusDisplayEvent event = {
+        .type = DBUS_DISPLAY_CHARDEV_OPEN,
+        .chardev = dc,
+    };
+    g_autoptr(ChardevBackend) be = NULL;
+    g_autoptr(QemuOpts) opts = NULL;
+
+    dc->iface = qemu_dbus_display1_chardev_skeleton_new();
+    g_object_set(dc->iface, "name", backend->u.dbus.data->name, NULL);
+    g_object_connect(dc->iface,
+                     "swapped-signal::handle-register",
+                     dbus_chr_register, dc,
+                     "swapped-signal::handle-send-break",
+                     dbus_chr_send_break, dc,
+                     NULL);
+
+    dbus_display_notify(&event);
+
+    be = g_new0(ChardevBackend, 1);
+    opts = qemu_opts_create(qemu_find_opts("chardev"), NULL, 0, &error_abort);
+    qemu_opt_set(opts, "server", "on", &error_abort);
+    qemu_opt_set(opts, "wait", "off", &error_abort);
+    CHARDEV_CLASS(object_class_by_name(TYPE_CHARDEV_SOCKET))->parse(
+        opts, be, errp);
+    if (*errp) {
+        return;
+    }
+    CHARDEV_CLASS(object_class_by_name(TYPE_CHARDEV_SOCKET))->open(
+        chr, be, be_opened, errp);
+}
+
+static void
+dbus_chr_set_fe_open(Chardev *chr, int fe_open)
+{
+    DBusChardev *dc = DBUS_CHARDEV(chr);
+
+    g_object_set(dc->iface, "feopened", fe_open, NULL);
+}
+
+static void
+dbus_chr_set_echo(Chardev *chr, bool echo)
+{
+    DBusChardev *dc = DBUS_CHARDEV(chr);
+
+    g_object_set(dc->iface, "echo", echo, NULL);
+}
+
+static void
+dbus_chr_be_event(Chardev *chr, QEMUChrEvent event)
+{
+    DBusChardev *dc = DBUS_CHARDEV(chr);
+    DBusChardevClass *klass = DBUS_CHARDEV_GET_CLASS(chr);
+
+    switch (event) {
+    case CHR_EVENT_CLOSED:
+        if (dc->iface) {
+            /* on finalize, iface is set to NULL */
+            g_object_set(dc->iface, "owner", "", NULL);
+        }
+        break;
+    default:
+        break;
+    };
+
+    klass->parent_chr_be_event(chr, event);
+}
+
+static void
+dbus_chr_parse(QemuOpts *opts, ChardevBackend *backend,
+               Error **errp)
+{
+    const char *name = qemu_opt_get(opts, "name");
+    ChardevDBus *dbus;
+
+    if (name == NULL) {
+        error_setg(errp, "chardev: dbus: no name given");
+        return;
+    }
+
+    backend->type = CHARDEV_BACKEND_KIND_DBUS;
+    dbus = backend->u.dbus.data = g_new0(ChardevDBus, 1);
+    qemu_chr_parse_common(opts, qapi_ChardevDBus_base(dbus));
+    dbus->name = g_strdup(name);
+}
+
+static void
+char_dbus_class_init(ObjectClass *oc, void *data)
+{
+    DBusChardevClass *klass = DBUS_CHARDEV_CLASS(oc);
+    ChardevClass *cc = CHARDEV_CLASS(oc);
+
+    cc->parse = dbus_chr_parse;
+    cc->open = dbus_chr_open;
+    cc->chr_set_fe_open = dbus_chr_set_fe_open;
+    cc->chr_set_echo = dbus_chr_set_echo;
+    klass->parent_chr_be_event = cc->chr_be_event;
+    cc->chr_be_event = dbus_chr_be_event;
+}
+
+static void
+char_dbus_finalize(Object *obj)
+{
+    DBusChardev *dc = DBUS_CHARDEV(obj);
+    DBusDisplayEvent event = {
+        .type = DBUS_DISPLAY_CHARDEV_CLOSE,
+        .chardev = dc,
+    };
+
+    dbus_display_notify(&event);
+    g_clear_object(&dc->iface);
+}
+
+static const TypeInfo char_dbus_type_info = {
+    .name = TYPE_CHARDEV_DBUS,
+    .parent = TYPE_CHARDEV_SOCKET,
+    .class_size = sizeof(DBusChardevClass),
+    .instance_size = sizeof(DBusChardev),
+    .instance_finalize = char_dbus_finalize,
+    .class_init = char_dbus_class_init,
+};
+module_obj(TYPE_CHARDEV_DBUS);
+
+static void
+register_types(void)
+{
+    type_register_static(&char_dbus_type_info);
+}
+
+type_init(register_types);