Add dbus-vmstate object
When instantiated, this object will connect to the given D-Bus bus "addr". During migration, it will take/restore the data from org.qemu.VMState1 instances. See documentation for details. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Marc-André Lureau
parent
a5021d6991
commit
5010cec2bc
@ -2209,9 +2209,11 @@ F: qapi/migration.json
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D-Bus
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M: Marc-André Lureau <marcandre.lureau@redhat.com>
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S: Maintained
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F: backends/dbus-vmstate.c
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F: util/dbus.c
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F: include/qemu/dbus.h
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F: docs/interop/dbus.rst
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F: docs/interop/dbus-vmstate.rst
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Seccomp
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M: Eduardo Otubo <otubo@redhat.com>
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@ -128,6 +128,7 @@ vhost-user-gpu-obj-y = contrib/vhost-user-gpu/
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trace-events-subdirs =
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trace-events-subdirs += accel/kvm
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trace-events-subdirs += accel/tcg
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trace-events-subdirs += backends
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trace-events-subdirs += crypto
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trace-events-subdirs += monitor
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ifeq ($(CONFIG_USER_ONLY),y)
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@ -17,3 +17,7 @@ endif
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common-obj-$(call land,$(CONFIG_VHOST_USER),$(CONFIG_VIRTIO)) += vhost-user.o
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common-obj-$(CONFIG_LINUX) += hostmem-memfd.o
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common-obj-$(CONFIG_GIO) += dbus-vmstate.o
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dbus-vmstate.o-cflags = $(GIO_CFLAGS)
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dbus-vmstate.o-libs = $(GIO_LIBS)
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510
backends/dbus-vmstate.c
Normal file
510
backends/dbus-vmstate.c
Normal file
@ -0,0 +1,510 @@
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/*
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* QEMU dbus-vmstate
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*
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* Copyright (C) 2019 Red Hat Inc
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*
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* Authors:
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* Marc-André Lureau <marcandre.lureau@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "qemu/units.h"
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#include "qemu/dbus.h"
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#include "qemu/error-report.h"
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#include "qapi/error.h"
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#include "qom/object_interfaces.h"
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#include "qapi/qmp/qerror.h"
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#include "migration/vmstate.h"
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#include "trace.h"
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typedef struct DBusVMState DBusVMState;
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typedef struct DBusVMStateClass DBusVMStateClass;
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#define TYPE_DBUS_VMSTATE "dbus-vmstate"
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#define DBUS_VMSTATE(obj) \
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OBJECT_CHECK(DBusVMState, (obj), TYPE_DBUS_VMSTATE)
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#define DBUS_VMSTATE_GET_CLASS(obj) \
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OBJECT_GET_CLASS(DBusVMStateClass, (obj), TYPE_DBUS_VMSTATE)
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#define DBUS_VMSTATE_CLASS(klass) \
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OBJECT_CLASS_CHECK(DBusVMStateClass, (klass), TYPE_DBUS_VMSTATE)
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struct DBusVMStateClass {
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ObjectClass parent_class;
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};
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struct DBusVMState {
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Object parent;
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GDBusConnection *bus;
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char *dbus_addr;
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char *id_list;
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uint32_t data_size;
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uint8_t *data;
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};
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static const GDBusPropertyInfo vmstate_property_info[] = {
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{ -1, (char *) "Id", (char *) "s",
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G_DBUS_PROPERTY_INFO_FLAGS_READABLE, NULL },
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};
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static const GDBusPropertyInfo * const vmstate_property_info_pointers[] = {
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&vmstate_property_info[0],
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NULL
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};
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static const GDBusInterfaceInfo vmstate1_interface_info = {
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-1,
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(char *) "org.qemu.VMState1",
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(GDBusMethodInfo **) NULL,
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(GDBusSignalInfo **) NULL,
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(GDBusPropertyInfo **) &vmstate_property_info_pointers,
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NULL,
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};
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#define DBUS_VMSTATE_SIZE_LIMIT (1 * MiB)
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static GHashTable *
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get_id_list_set(DBusVMState *self)
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{
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g_auto(GStrv) ids = NULL;
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g_autoptr(GHashTable) set = NULL;
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int i;
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if (!self->id_list) {
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return NULL;
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}
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ids = g_strsplit(self->id_list, ",", -1);
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set = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, NULL);
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for (i = 0; ids[i]; i++) {
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g_hash_table_add(set, ids[i]);
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ids[i] = NULL;
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}
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return g_steal_pointer(&set);
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}
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static GHashTable *
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dbus_get_proxies(DBusVMState *self, GError **err)
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{
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g_autoptr(GHashTable) proxies = NULL;
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g_autoptr(GHashTable) ids = NULL;
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g_auto(GStrv) names = NULL;
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Error *error = NULL;
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size_t i;
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ids = get_id_list_set(self);
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proxies = g_hash_table_new_full(g_str_hash, g_str_equal,
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g_free, g_object_unref);
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names = qemu_dbus_get_queued_owners(self->bus, "org.qemu.VMState1", &error);
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if (!names) {
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g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED, "%s",
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error_get_pretty(error));
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error_free(error);
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return NULL;
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}
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for (i = 0; names[i]; i++) {
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g_autoptr(GDBusProxy) proxy = NULL;
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g_autoptr(GVariant) result = NULL;
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g_autofree char *id = NULL;
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size_t size;
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proxy = g_dbus_proxy_new_sync(self->bus, G_DBUS_PROXY_FLAGS_NONE,
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(GDBusInterfaceInfo *) &vmstate1_interface_info,
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names[i],
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"/org/qemu/VMState1",
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"org.qemu.VMState1",
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NULL, err);
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if (!proxy) {
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return NULL;
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}
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result = g_dbus_proxy_get_cached_property(proxy, "Id");
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if (!result) {
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g_set_error_literal(err, G_IO_ERROR, G_IO_ERROR_FAILED,
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"VMState Id property is missing.");
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return NULL;
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}
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id = g_variant_dup_string(result, &size);
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if (ids && !g_hash_table_remove(ids, id)) {
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g_clear_pointer(&id, g_free);
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g_clear_object(&proxy);
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continue;
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}
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if (size == 0 || size >= 256) {
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g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
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"VMState Id '%s' is invalid.", id);
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return NULL;
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}
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if (!g_hash_table_insert(proxies, id, proxy)) {
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g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Duplicated VMState Id '%s'", id);
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return NULL;
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}
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id = NULL;
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proxy = NULL;
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g_clear_pointer(&result, g_variant_unref);
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}
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if (ids) {
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g_autofree char **left = NULL;
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left = (char **)g_hash_table_get_keys_as_array(ids, NULL);
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if (*left) {
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g_autofree char *leftids = g_strjoinv(",", left);
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g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
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"Required VMState Id are missing: %s", leftids);
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return NULL;
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}
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}
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return g_steal_pointer(&proxies);
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}
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static int
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dbus_load_state_proxy(GDBusProxy *proxy, const uint8_t *data, size_t size)
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{
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g_autoptr(GError) err = NULL;
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g_autoptr(GVariant) result = NULL;
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g_autoptr(GVariant) value = NULL;
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value = g_variant_new_fixed_array(G_VARIANT_TYPE_BYTE,
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data, size, sizeof(char));
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result = g_dbus_proxy_call_sync(proxy, "Load",
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g_variant_new("(@ay)",
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g_steal_pointer(&value)),
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G_DBUS_CALL_FLAGS_NO_AUTO_START,
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-1, NULL, &err);
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if (!result) {
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error_report("%s: Failed to Load: %s", __func__, err->message);
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return -1;
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}
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return 0;
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}
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static int dbus_vmstate_post_load(void *opaque, int version_id)
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{
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DBusVMState *self = DBUS_VMSTATE(opaque);
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g_autoptr(GInputStream) m = NULL;
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g_autoptr(GDataInputStream) s = NULL;
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g_autoptr(GError) err = NULL;
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g_autoptr(GHashTable) proxies = NULL;
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uint32_t nelem;
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trace_dbus_vmstate_post_load(version_id);
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proxies = dbus_get_proxies(self, &err);
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if (!proxies) {
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error_report("%s: Failed to get proxies: %s", __func__, err->message);
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return -1;
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}
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m = g_memory_input_stream_new_from_data(self->data, self->data_size, NULL);
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s = g_data_input_stream_new(m);
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g_data_input_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
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nelem = g_data_input_stream_read_uint32(s, NULL, &err);
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if (err) {
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goto error;
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}
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while (nelem > 0) {
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GDBusProxy *proxy = NULL;
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uint32_t len;
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gsize bytes_read, avail;
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char id[256];
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len = g_data_input_stream_read_uint32(s, NULL, &err);
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if (err) {
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goto error;
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}
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if (len >= 256) {
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error_report("%s: Invalid DBus vmstate proxy name %u",
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__func__, len);
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return -1;
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}
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if (!g_input_stream_read_all(G_INPUT_STREAM(s), id, len,
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&bytes_read, NULL, &err)) {
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goto error;
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}
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g_return_val_if_fail(bytes_read == len, -1);
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id[len] = 0;
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trace_dbus_vmstate_loading(id);
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proxy = g_hash_table_lookup(proxies, id);
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if (!proxy) {
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error_report("%s: Failed to find proxy Id '%s'", __func__, id);
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return -1;
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}
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len = g_data_input_stream_read_uint32(s, NULL, &err);
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avail = g_buffered_input_stream_get_available(
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G_BUFFERED_INPUT_STREAM(s));
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if (len > DBUS_VMSTATE_SIZE_LIMIT || len > avail) {
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error_report("%s: Invalid vmstate size: %u", __func__, len);
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return -1;
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}
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if (dbus_load_state_proxy(proxy,
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g_buffered_input_stream_peek_buffer(G_BUFFERED_INPUT_STREAM(s),
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NULL),
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len) < 0) {
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error_report("%s: Failed to restore Id '%s'", __func__, id);
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return -1;
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}
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if (!g_seekable_seek(G_SEEKABLE(s), len, G_SEEK_CUR, NULL, &err)) {
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goto error;
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}
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nelem -= 1;
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}
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return 0;
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error:
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error_report("%s: Failed to read from stream: %s", __func__, err->message);
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return -1;
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}
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static void
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dbus_save_state_proxy(gpointer key,
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gpointer value,
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gpointer user_data)
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{
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GDataOutputStream *s = user_data;
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const char *id = key;
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GDBusProxy *proxy = value;
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g_autoptr(GVariant) result = NULL;
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g_autoptr(GVariant) child = NULL;
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g_autoptr(GError) err = NULL;
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const uint8_t *data;
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gsize size;
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trace_dbus_vmstate_saving(id);
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result = g_dbus_proxy_call_sync(proxy, "Save",
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NULL, G_DBUS_CALL_FLAGS_NO_AUTO_START,
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-1, NULL, &err);
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if (!result) {
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error_report("%s: Failed to Save: %s", __func__, err->message);
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return;
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}
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child = g_variant_get_child_value(result, 0);
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data = g_variant_get_fixed_array(child, &size, sizeof(char));
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if (!data) {
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error_report("%s: Failed to Save: not a byte array", __func__);
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return;
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}
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if (size > DBUS_VMSTATE_SIZE_LIMIT) {
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error_report("%s: Too large vmstate data to save: %zu",
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__func__, (size_t)size);
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return;
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}
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if (!g_data_output_stream_put_uint32(s, strlen(id), NULL, &err) ||
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!g_data_output_stream_put_string(s, id, NULL, &err) ||
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!g_data_output_stream_put_uint32(s, size, NULL, &err) ||
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!g_output_stream_write_all(G_OUTPUT_STREAM(s),
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data, size, NULL, NULL, &err)) {
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error_report("%s: Failed to write to stream: %s",
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__func__, err->message);
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}
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}
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static int dbus_vmstate_pre_save(void *opaque)
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{
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DBusVMState *self = DBUS_VMSTATE(opaque);
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g_autoptr(GOutputStream) m = NULL;
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g_autoptr(GDataOutputStream) s = NULL;
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g_autoptr(GHashTable) proxies = NULL;
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g_autoptr(GError) err = NULL;
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trace_dbus_vmstate_pre_save();
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proxies = dbus_get_proxies(self, &err);
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if (!proxies) {
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error_report("%s: Failed to get proxies: %s", __func__, err->message);
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return -1;
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}
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m = g_memory_output_stream_new_resizable();
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s = g_data_output_stream_new(m);
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g_data_output_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
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if (!g_data_output_stream_put_uint32(s, g_hash_table_size(proxies),
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NULL, &err)) {
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error_report("%s: Failed to write to stream: %s",
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__func__, err->message);
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return -1;
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}
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g_hash_table_foreach(proxies, dbus_save_state_proxy, s);
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if (g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m))
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> UINT32_MAX) {
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error_report("%s: DBus vmstate buffer is too large", __func__);
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return -1;
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}
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if (!g_output_stream_close(G_OUTPUT_STREAM(m), NULL, &err)) {
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error_report("%s: Failed to close stream: %s", __func__, err->message);
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return -1;
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}
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g_free(self->data);
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self->data_size =
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g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m));
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self->data =
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g_memory_output_stream_steal_data(G_MEMORY_OUTPUT_STREAM(m));
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return 0;
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}
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static const VMStateDescription dbus_vmstate = {
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.name = TYPE_DBUS_VMSTATE,
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.version_id = 0,
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.pre_save = dbus_vmstate_pre_save,
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.post_load = dbus_vmstate_post_load,
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.fields = (VMStateField[]) {
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VMSTATE_UINT32(data_size, DBusVMState),
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VMSTATE_VBUFFER_ALLOC_UINT32(data, DBusVMState, 0, 0, data_size),
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VMSTATE_END_OF_LIST()
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}
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};
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static void
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dbus_vmstate_complete(UserCreatable *uc, Error **errp)
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{
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DBusVMState *self = DBUS_VMSTATE(uc);
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g_autoptr(GError) err = NULL;
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if (!object_resolve_path_type("", TYPE_DBUS_VMSTATE, NULL)) {
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error_setg(errp, "There is already an instance of %s",
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TYPE_DBUS_VMSTATE);
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return;
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}
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if (!self->dbus_addr) {
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error_setg(errp, QERR_MISSING_PARAMETER, "addr");
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return;
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}
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self->bus = g_dbus_connection_new_for_address_sync(self->dbus_addr,
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G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
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G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION,
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NULL, NULL, &err);
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if (err) {
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error_setg(errp, "failed to connect to DBus: '%s'", err->message);
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return;
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}
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if (vmstate_register(VMSTATE_IF(self), -1, &dbus_vmstate, self) < 0) {
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error_setg(errp, "Failed to register vmstate");
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}
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}
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static void
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dbus_vmstate_finalize(Object *o)
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{
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DBusVMState *self = DBUS_VMSTATE(o);
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|
||||
vmstate_unregister(VMSTATE_IF(self), &dbus_vmstate, self);
|
||||
|
||||
g_clear_object(&self->bus);
|
||||
g_free(self->dbus_addr);
|
||||
g_free(self->id_list);
|
||||
g_free(self->data);
|
||||
}
|
||||
|
||||
static char *
|
||||
get_dbus_addr(Object *o, Error **errp)
|
||||
{
|
||||
DBusVMState *self = DBUS_VMSTATE(o);
|
||||
|
||||
return g_strdup(self->dbus_addr);
|
||||
}
|
||||
|
||||
static void
|
||||
set_dbus_addr(Object *o, const char *str, Error **errp)
|
||||
{
|
||||
DBusVMState *self = DBUS_VMSTATE(o);
|
||||
|
||||
g_free(self->dbus_addr);
|
||||
self->dbus_addr = g_strdup(str);
|
||||
}
|
||||
|
||||
static char *
|
||||
get_id_list(Object *o, Error **errp)
|
||||
{
|
||||
DBusVMState *self = DBUS_VMSTATE(o);
|
||||
|
||||
return g_strdup(self->id_list);
|
||||
}
|
||||
|
||||
static void
|
||||
set_id_list(Object *o, const char *str, Error **errp)
|
||||
{
|
||||
DBusVMState *self = DBUS_VMSTATE(o);
|
||||
|
||||
g_free(self->id_list);
|
||||
self->id_list = g_strdup(str);
|
||||
}
|
||||
|
||||
static char *
|
||||
dbus_vmstate_get_id(VMStateIf *vmif)
|
||||
{
|
||||
return g_strdup(TYPE_DBUS_VMSTATE);
|
||||
}
|
||||
|
||||
static void
|
||||
dbus_vmstate_class_init(ObjectClass *oc, void *data)
|
||||
{
|
||||
UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
|
||||
VMStateIfClass *vc = VMSTATE_IF_CLASS(oc);
|
||||
|
||||
ucc->complete = dbus_vmstate_complete;
|
||||
vc->get_id = dbus_vmstate_get_id;
|
||||
|
||||
object_class_property_add_str(oc, "addr",
|
||||
get_dbus_addr, set_dbus_addr,
|
||||
&error_abort);
|
||||
object_class_property_add_str(oc, "id-list",
|
||||
get_id_list, set_id_list,
|
||||
&error_abort);
|
||||
}
|
||||
|
||||
static const TypeInfo dbus_vmstate_info = {
|
||||
.name = TYPE_DBUS_VMSTATE,
|
||||
.parent = TYPE_OBJECT,
|
||||
.instance_size = sizeof(DBusVMState),
|
||||
.instance_finalize = dbus_vmstate_finalize,
|
||||
.class_size = sizeof(DBusVMStateClass),
|
||||
.class_init = dbus_vmstate_class_init,
|
||||
.interfaces = (InterfaceInfo[]) {
|
||||
{ TYPE_USER_CREATABLE },
|
||||
{ TYPE_VMSTATE_IF },
|
||||
{ }
|
||||
}
|
||||
};
|
||||
|
||||
static void
|
||||
register_types(void)
|
||||
{
|
||||
type_register_static(&dbus_vmstate_info);
|
||||
}
|
||||
|
||||
type_init(register_types);
|
||||
7
backends/trace-events
Normal file
7
backends/trace-events
Normal file
@ -0,0 +1,7 @@
|
||||
# See docs/devel/tracing.txt for syntax documentation.
|
||||
|
||||
# dbus-vmstate.c
|
||||
dbus_vmstate_pre_save(void)
|
||||
dbus_vmstate_post_load(int version_id) "version_id: %d"
|
||||
dbus_vmstate_loading(const char *id) "id: %s"
|
||||
dbus_vmstate_saving(const char *id) "id: %s"
|
||||
74
docs/interop/dbus-vmstate.rst
Normal file
74
docs/interop/dbus-vmstate.rst
Normal file
@ -0,0 +1,74 @@
|
||||
=============
|
||||
D-Bus VMState
|
||||
=============
|
||||
|
||||
Introduction
|
||||
============
|
||||
|
||||
The QEMU dbus-vmstate object's aim is to migrate helpers' data running
|
||||
on a QEMU D-Bus bus. (refer to the :doc:`dbus` document for
|
||||
some recommendations on D-Bus usage)
|
||||
|
||||
Upon migration, QEMU will go through the queue of
|
||||
``org.qemu.VMState1`` D-Bus name owners and query their ``Id``. It
|
||||
must be unique among the helpers.
|
||||
|
||||
It will then save arbitrary data of each Id to be transferred in the
|
||||
migration stream and restored/loaded at the corresponding destination
|
||||
helper.
|
||||
|
||||
For now, the data amount to be transferred is arbitrarily limited to
|
||||
1Mb. The state must be saved quickly (a fraction of a second). (D-Bus
|
||||
imposes a time limit on reply anyway, and migration would fail if data
|
||||
isn't given quickly enough.)
|
||||
|
||||
dbus-vmstate object can be configured with the expected list of
|
||||
helpers by setting its ``id-list`` property, with a comma-separated
|
||||
``Id`` list.
|
||||
|
||||
Interface
|
||||
=========
|
||||
|
||||
On object path ``/org/qemu/VMState1``, the following
|
||||
``org.qemu.VMState1`` interface should be implemented:
|
||||
|
||||
.. code:: xml
|
||||
|
||||
<interface name="org.qemu.VMState1">
|
||||
<property name="Id" type="s" access="read"/>
|
||||
<method name="Load">
|
||||
<arg type="ay" name="data" direction="in"/>
|
||||
</method>
|
||||
<method name="Save">
|
||||
<arg type="ay" name="data" direction="out"/>
|
||||
</method>
|
||||
</interface>
|
||||
|
||||
"Id" property
|
||||
-------------
|
||||
|
||||
A string that identifies the helper uniquely. (maximum 256 bytes
|
||||
including terminating NUL byte)
|
||||
|
||||
.. note::
|
||||
|
||||
The helper ID namespace is a separate namespace. In particular, it is not
|
||||
related to QEMU "id" used in -object/-device objects.
|
||||
|
||||
Load(in u8[] bytes) method
|
||||
--------------------------
|
||||
|
||||
The method called on destination with the state to restore.
|
||||
|
||||
The helper may be initially started in a waiting state (with
|
||||
an --incoming argument for example), and it may resume on success.
|
||||
|
||||
An error may be returned to the caller.
|
||||
|
||||
Save(out u8[] bytes) method
|
||||
---------------------------
|
||||
|
||||
The method called on the source to get the current state to be
|
||||
migrated. The helper should continue to run normally.
|
||||
|
||||
An error may be returned to the caller.
|
||||
@ -103,3 +103,8 @@ https://dbus.freedesktop.org/doc/dbus-api-design.html
|
||||
|
||||
The "org.qemu.*" prefix is reserved for services implemented &
|
||||
distributed by the QEMU project.
|
||||
|
||||
QEMU Interfaces
|
||||
===============
|
||||
|
||||
:doc:`dbus-vmstate`
|
||||
|
||||
@ -14,6 +14,7 @@ Contents:
|
||||
|
||||
bitmaps
|
||||
dbus
|
||||
dbus-vmstate
|
||||
live-block-operations
|
||||
pr-helper
|
||||
qemu-ga
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user