qemu/backends/dbus-vmstate.c

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/*
* QEMU dbus-vmstate
*
* Copyright (C) 2019 Red Hat Inc
*
* Authors:
* Marc-André Lureau <marcandre.lureau@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/units.h"
#include "qemu/dbus.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "qom/object_interfaces.h"
#include "qapi/qmp/qerror.h"
#include "migration/vmstate.h"
#include "trace.h"
#include "qom/object.h"
#define TYPE_DBUS_VMSTATE "dbus-vmstate"
OBJECT_DECLARE_SIMPLE_TYPE(DBusVMState,
DBUS_VMSTATE)
struct DBusVMState {
Object parent;
GDBusConnection *bus;
char *dbus_addr;
char *id_list;
uint32_t data_size;
uint8_t *data;
};
static const GDBusPropertyInfo vmstate_property_info[] = {
{ -1, (char *) "Id", (char *) "s",
G_DBUS_PROPERTY_INFO_FLAGS_READABLE, NULL },
};
static const GDBusPropertyInfo * const vmstate_property_info_pointers[] = {
&vmstate_property_info[0],
NULL
};
static const GDBusInterfaceInfo vmstate1_interface_info = {
-1,
(char *) "org.qemu.VMState1",
(GDBusMethodInfo **) NULL,
(GDBusSignalInfo **) NULL,
(GDBusPropertyInfo **) &vmstate_property_info_pointers,
NULL,
};
#define DBUS_VMSTATE_SIZE_LIMIT (1 * MiB)
static GHashTable *
get_id_list_set(DBusVMState *self)
{
g_auto(GStrv) ids = NULL;
g_autoptr(GHashTable) set = NULL;
int i;
if (!self->id_list) {
return NULL;
}
ids = g_strsplit(self->id_list, ",", -1);
set = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, NULL);
for (i = 0; ids[i]; i++) {
g_hash_table_add(set, ids[i]);
ids[i] = NULL;
}
return g_steal_pointer(&set);
}
static GHashTable *
dbus_get_proxies(DBusVMState *self, GError **err)
{
g_autoptr(GHashTable) proxies = NULL;
g_autoptr(GHashTable) ids = NULL;
g_auto(GStrv) names = NULL;
Error *error = NULL;
size_t i;
ids = get_id_list_set(self);
proxies = g_hash_table_new_full(g_str_hash, g_str_equal,
g_free, g_object_unref);
names = qemu_dbus_get_queued_owners(self->bus, "org.qemu.VMState1", &error);
if (!names) {
g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED, "%s",
error_get_pretty(error));
error_free(error);
return NULL;
}
for (i = 0; names[i]; i++) {
g_autoptr(GDBusProxy) proxy = NULL;
g_autoptr(GVariant) result = NULL;
g_autofree char *id = NULL;
size_t size;
proxy = g_dbus_proxy_new_sync(self->bus, G_DBUS_PROXY_FLAGS_NONE,
(GDBusInterfaceInfo *) &vmstate1_interface_info,
names[i],
"/org/qemu/VMState1",
"org.qemu.VMState1",
NULL, err);
if (!proxy) {
if (err != NULL && *err != NULL) {
warn_report("%s: Failed to create proxy: %s",
__func__, (*err)->message);
g_clear_error(err);
}
continue;
}
result = g_dbus_proxy_get_cached_property(proxy, "Id");
if (!result) {
warn_report("%s: VMState Id property is missing.", __func__);
g_clear_object(&proxy);
continue;
}
id = g_variant_dup_string(result, &size);
if (ids && !g_hash_table_remove(ids, id)) {
g_clear_pointer(&id, g_free);
g_clear_object(&proxy);
continue;
}
if (size == 0 || size >= 256) {
g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
"VMState Id '%s' is invalid.", id);
return NULL;
}
if (!g_hash_table_insert(proxies, id, proxy)) {
g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
"Duplicated VMState Id '%s'", id);
return NULL;
}
id = NULL;
proxy = NULL;
g_clear_pointer(&result, g_variant_unref);
}
if (ids) {
g_autofree char **left = NULL;
left = (char **)g_hash_table_get_keys_as_array(ids, NULL);
if (*left) {
g_autofree char *leftids = g_strjoinv(",", left);
g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
"Required VMState Id are missing: %s", leftids);
return NULL;
}
}
return g_steal_pointer(&proxies);
}
static int
dbus_load_state_proxy(GDBusProxy *proxy, const uint8_t *data, size_t size)
{
g_autoptr(GError) err = NULL;
g_autoptr(GVariant) result = NULL;
g_autoptr(GVariant) value = NULL;
value = g_variant_new_fixed_array(G_VARIANT_TYPE_BYTE,
data, size, sizeof(char));
result = g_dbus_proxy_call_sync(proxy, "Load",
g_variant_new("(@ay)",
g_steal_pointer(&value)),
G_DBUS_CALL_FLAGS_NO_AUTO_START,
-1, NULL, &err);
if (!result) {
error_report("%s: Failed to Load: %s", __func__, err->message);
return -1;
}
return 0;
}
static int dbus_vmstate_post_load(void *opaque, int version_id)
{
DBusVMState *self = DBUS_VMSTATE(opaque);
g_autoptr(GInputStream) m = NULL;
g_autoptr(GDataInputStream) s = NULL;
g_autoptr(GError) err = NULL;
g_autoptr(GHashTable) proxies = NULL;
uint32_t nelem;
trace_dbus_vmstate_post_load(version_id);
proxies = dbus_get_proxies(self, &err);
if (!proxies) {
error_report("%s: Failed to get proxies: %s", __func__, err->message);
return -1;
}
m = g_memory_input_stream_new_from_data(self->data, self->data_size, NULL);
s = g_data_input_stream_new(m);
g_data_input_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
g_buffered_input_stream_set_buffer_size(G_BUFFERED_INPUT_STREAM(s),
DBUS_VMSTATE_SIZE_LIMIT);
nelem = g_data_input_stream_read_uint32(s, NULL, &err);
if (err) {
goto error;
}
while (nelem > 0) {
GDBusProxy *proxy = NULL;
uint32_t len;
gsize bytes_read, avail;
char id[256];
len = g_data_input_stream_read_uint32(s, NULL, &err);
if (err) {
goto error;
}
if (len >= 256) {
error_report("%s: Invalid DBus vmstate proxy name %u",
__func__, len);
return -1;
}
if (!g_input_stream_read_all(G_INPUT_STREAM(s), id, len,
&bytes_read, NULL, &err)) {
goto error;
}
if (bytes_read != len) {
error_report("%s: Short read", __func__);
return -1;
}
id[len] = 0;
trace_dbus_vmstate_loading(id);
proxy = g_hash_table_lookup(proxies, id);
if (!proxy) {
error_report("%s: Failed to find proxy Id '%s'", __func__, id);
return -1;
}
len = g_data_input_stream_read_uint32(s, NULL, &err);
if (len > DBUS_VMSTATE_SIZE_LIMIT) {
error_report("%s: Invalid vmstate size: %u", __func__, len);
return -1;
}
g_buffered_input_stream_fill(G_BUFFERED_INPUT_STREAM(s), len, NULL,
&err);
if (err) {
goto error;
}
avail = g_buffered_input_stream_get_available(
G_BUFFERED_INPUT_STREAM(s));
if (len > avail) {
error_report("%s: Not enough data available to load for Id: '%s'. "
"Available data size: %zu, Actual vmstate size: %u",
__func__, id, avail, len);
return -1;
}
if (dbus_load_state_proxy(proxy,
g_buffered_input_stream_peek_buffer(G_BUFFERED_INPUT_STREAM(s),
NULL),
len) < 0) {
error_report("%s: Failed to restore Id '%s'", __func__, id);
return -1;
}
if (!g_seekable_seek(G_SEEKABLE(s), len, G_SEEK_CUR, NULL, &err)) {
goto error;
}
nelem -= 1;
}
return 0;
error:
error_report("%s: Failed to read from stream: %s", __func__, err->message);
return -1;
}
static void
dbus_save_state_proxy(gpointer key,
gpointer value,
gpointer user_data)
{
GDataOutputStream *s = user_data;
const char *id = key;
GDBusProxy *proxy = value;
g_autoptr(GVariant) result = NULL;
g_autoptr(GVariant) child = NULL;
g_autoptr(GError) err = NULL;
const uint8_t *data;
gsize size;
trace_dbus_vmstate_saving(id);
result = g_dbus_proxy_call_sync(proxy, "Save",
NULL, G_DBUS_CALL_FLAGS_NO_AUTO_START,
-1, NULL, &err);
if (!result) {
error_report("%s: Failed to Save: %s", __func__, err->message);
return;
}
child = g_variant_get_child_value(result, 0);
data = g_variant_get_fixed_array(child, &size, sizeof(char));
if (!data) {
error_report("%s: Failed to Save: not a byte array", __func__);
return;
}
if (size > DBUS_VMSTATE_SIZE_LIMIT) {
error_report("%s: Too large vmstate data to save: %zu",
__func__, (size_t)size);
return;
}
if (!g_data_output_stream_put_uint32(s, strlen(id), NULL, &err) ||
!g_data_output_stream_put_string(s, id, NULL, &err) ||
!g_data_output_stream_put_uint32(s, size, NULL, &err) ||
!g_output_stream_write_all(G_OUTPUT_STREAM(s),
data, size, NULL, NULL, &err)) {
error_report("%s: Failed to write to stream: %s",
__func__, err->message);
}
}
static int dbus_vmstate_pre_save(void *opaque)
{
DBusVMState *self = DBUS_VMSTATE(opaque);
g_autoptr(GOutputStream) m = NULL;
g_autoptr(GDataOutputStream) s = NULL;
g_autoptr(GHashTable) proxies = NULL;
g_autoptr(GError) err = NULL;
trace_dbus_vmstate_pre_save();
proxies = dbus_get_proxies(self, &err);
if (!proxies) {
error_report("%s: Failed to get proxies: %s", __func__, err->message);
return -1;
}
m = g_memory_output_stream_new_resizable();
s = g_data_output_stream_new(m);
g_data_output_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
if (!g_data_output_stream_put_uint32(s, g_hash_table_size(proxies),
NULL, &err)) {
error_report("%s: Failed to write to stream: %s",
__func__, err->message);
return -1;
}
g_hash_table_foreach(proxies, dbus_save_state_proxy, s);
if (g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m))
> UINT32_MAX) {
error_report("%s: DBus vmstate buffer is too large", __func__);
return -1;
}
if (!g_output_stream_close(G_OUTPUT_STREAM(m), NULL, &err)) {
error_report("%s: Failed to close stream: %s", __func__, err->message);
return -1;
}
g_free(self->data);
self->data_size =
g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m));
self->data =
g_memory_output_stream_steal_data(G_MEMORY_OUTPUT_STREAM(m));
return 0;
}
static const VMStateDescription dbus_vmstate = {
.name = TYPE_DBUS_VMSTATE,
.version_id = 0,
.pre_save = dbus_vmstate_pre_save,
.post_load = dbus_vmstate_post_load,
.fields = (VMStateField[]) {
VMSTATE_UINT32(data_size, DBusVMState),
VMSTATE_VBUFFER_ALLOC_UINT32(data, DBusVMState, 0, 0, data_size),
VMSTATE_END_OF_LIST()
}
};
static void
dbus_vmstate_complete(UserCreatable *uc, Error **errp)
{
DBusVMState *self = DBUS_VMSTATE(uc);
g_autoptr(GError) err = NULL;
if (!object_resolve_path_type("", TYPE_DBUS_VMSTATE, NULL)) {
error_setg(errp, "There is already an instance of %s",
TYPE_DBUS_VMSTATE);
return;
}
if (!self->dbus_addr) {
error_setg(errp, QERR_MISSING_PARAMETER, "addr");
return;
}
self->bus = g_dbus_connection_new_for_address_sync(self->dbus_addr,
G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION,
NULL, NULL, &err);
if (err) {
error_setg(errp, "failed to connect to DBus: '%s'", err->message);
return;
}
if (vmstate_register_any(VMSTATE_IF(self), &dbus_vmstate, self) < 0) {
error_setg(errp, "Failed to register vmstate");
}
}
static void
dbus_vmstate_finalize(Object *o)
{
DBusVMState *self = DBUS_VMSTATE(o);
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",
qom: Drop parameter @errp of object_property_add() & friends The only way object_property_add() can fail is when a property with the same name already exists. Since our property names are all hardcoded, failure is a programming error, and the appropriate way to handle it is passing &error_abort. Same for its variants, except for object_property_add_child(), which additionally fails when the child already has a parent. Parentage is also under program control, so this is a programming error, too. We have a bit over 500 callers. Almost half of them pass &error_abort, slightly fewer ignore errors, one test case handles errors, and the remaining few callers pass them to their own callers. The previous few commits demonstrated once again that ignoring programming errors is a bad idea. Of the few ones that pass on errors, several violate the Error API. The Error ** argument must be NULL, &error_abort, &error_fatal, or a pointer to a variable containing NULL. Passing an argument of the latter kind twice without clearing it in between is wrong: if the first call sets an error, it no longer points to NULL for the second call. ich9_pm_add_properties(), sparc32_ledma_realize(), sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize() are wrong that way. When the one appropriate choice of argument is &error_abort, letting users pick the argument is a bad idea. Drop parameter @errp and assert the preconditions instead. There's one exception to "duplicate property name is a programming error": the way object_property_add() implements the magic (and undocumented) "automatic arrayification". Don't drop @errp there. Instead, rename object_property_add() to object_property_try_add(), and add the obvious wrapper object_property_add(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20200505152926.18877-15-armbru@redhat.com> [Two semantic rebase conflicts resolved]
2020-05-05 18:29:22 +03:00
get_dbus_addr, set_dbus_addr);
object_class_property_add_str(oc, "id-list",
qom: Drop parameter @errp of object_property_add() & friends The only way object_property_add() can fail is when a property with the same name already exists. Since our property names are all hardcoded, failure is a programming error, and the appropriate way to handle it is passing &error_abort. Same for its variants, except for object_property_add_child(), which additionally fails when the child already has a parent. Parentage is also under program control, so this is a programming error, too. We have a bit over 500 callers. Almost half of them pass &error_abort, slightly fewer ignore errors, one test case handles errors, and the remaining few callers pass them to their own callers. The previous few commits demonstrated once again that ignoring programming errors is a bad idea. Of the few ones that pass on errors, several violate the Error API. The Error ** argument must be NULL, &error_abort, &error_fatal, or a pointer to a variable containing NULL. Passing an argument of the latter kind twice without clearing it in between is wrong: if the first call sets an error, it no longer points to NULL for the second call. ich9_pm_add_properties(), sparc32_ledma_realize(), sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize() are wrong that way. When the one appropriate choice of argument is &error_abort, letting users pick the argument is a bad idea. Drop parameter @errp and assert the preconditions instead. There's one exception to "duplicate property name is a programming error": the way object_property_add() implements the magic (and undocumented) "automatic arrayification". Don't drop @errp there. Instead, rename object_property_add() to object_property_try_add(), and add the obvious wrapper object_property_add(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20200505152926.18877-15-armbru@redhat.com> [Two semantic rebase conflicts resolved]
2020-05-05 18:29:22 +03:00
get_id_list, set_id_list);
}
static const TypeInfo dbus_vmstate_info = {
.name = TYPE_DBUS_VMSTATE,
.parent = TYPE_OBJECT,
.instance_size = sizeof(DBusVMState),
.instance_finalize = dbus_vmstate_finalize,
.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);