backends/dbus-vmstate.c

   1 /*
   2  * QEMU dbus-vmstate
   3  *
   4  * Copyright (C) 2019 Red Hat Inc
   5  *
   6  * Authors:
   7  *  Marc-André Lureau <marcandre.lureau@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qemu/units.h"
  15 #include "qemu/dbus.h"
  16 #include "qemu/error-report.h"
  17 #include "qapi/error.h"
  18 #include "qom/object_interfaces.h"
  19 #include "qapi/qmp/qerror.h"
  20 #include "migration/vmstate.h"
  21 #include "trace.h"
  22
  23 typedef struct DBusVMState DBusVMState;
  24 typedef struct DBusVMStateClass DBusVMStateClass;
  25
  26 #define TYPE_DBUS_VMSTATE "dbus-vmstate"
  27 #define DBUS_VMSTATE(obj)                                \
  28     OBJECT_CHECK(DBusVMState, (obj), TYPE_DBUS_VMSTATE)
  29 #define DBUS_VMSTATE_GET_CLASS(obj)                              \
  30     OBJECT_GET_CLASS(DBusVMStateClass, (obj), TYPE_DBUS_VMSTATE)
  31 #define DBUS_VMSTATE_CLASS(klass)                                    \
  32     OBJECT_CLASS_CHECK(DBusVMStateClass, (klass), TYPE_DBUS_VMSTATE)
  33
  34 struct DBusVMStateClass {
  35     ObjectClass parent_class;
  36 };
  37
  38 struct DBusVMState {
  39     Object parent;
  40
  41     GDBusConnection *bus;
  42     char *dbus_addr;
  43     char *id_list;
  44
  45     uint32_t data_size;
  46     uint8_t *data;
  47 };
  48
  49 static const GDBusPropertyInfo vmstate_property_info[] = {
  50     { -1, (char *) "Id", (char *) "s",
  51       G_DBUS_PROPERTY_INFO_FLAGS_READABLE, NULL },
  52 };
  53
  54 static const GDBusPropertyInfo * const vmstate_property_info_pointers[] = {
  55     &vmstate_property_info[0],
  56     NULL
  57 };
  58
  59 static const GDBusInterfaceInfo vmstate1_interface_info = {
  60     -1,
  61     (char *) "org.qemu.VMState1",
  62     (GDBusMethodInfo **) NULL,
  63     (GDBusSignalInfo **) NULL,
  64     (GDBusPropertyInfo **) &vmstate_property_info_pointers,
  65     NULL,
  66 };
  67
  68 #define DBUS_VMSTATE_SIZE_LIMIT (1 * MiB)
  69
  70 static GHashTable *
  71 get_id_list_set(DBusVMState *self)
  72 {
  73     g_auto(GStrv) ids = NULL;
  74     g_autoptr(GHashTable) set = NULL;
  75     int i;
  76
  77     if (!self->id_list) {
  78         return NULL;
  79     }
  80
  81     ids = g_strsplit(self->id_list, ",", -1);
  82     set = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, NULL);
  83     for (i = 0; ids[i]; i++) {
  84         g_hash_table_add(set, ids[i]);
  85         ids[i] = NULL;
  86     }
  87
  88     return g_steal_pointer(&set);
  89 }
  90
  91 static GHashTable *
  92 dbus_get_proxies(DBusVMState *self, GError **err)
  93 {
  94     g_autoptr(GHashTable) proxies = NULL;
  95     g_autoptr(GHashTable) ids = NULL;
  96     g_auto(GStrv) names = NULL;
  97     Error *error = NULL;
  98     size_t i;
  99
 100     ids = get_id_list_set(self);
 101     proxies = g_hash_table_new_full(g_str_hash, g_str_equal,
 102                                     g_free, g_object_unref);
 103
 104     names = qemu_dbus_get_queued_owners(self->bus, "org.qemu.VMState1", &error);
 105     if (!names) {
 106         g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED, "%s",
 107                     error_get_pretty(error));
 108         error_free(error);
 109         return NULL;
 110     }
 111
 112     for (i = 0; names[i]; i++) {
 113         g_autoptr(GDBusProxy) proxy = NULL;
 114         g_autoptr(GVariant) result = NULL;
 115         g_autofree char *id = NULL;
 116         size_t size;
 117
 118         proxy = g_dbus_proxy_new_sync(self->bus, G_DBUS_PROXY_FLAGS_NONE,
 119                     (GDBusInterfaceInfo *) &vmstate1_interface_info,
 120                     names[i],
 121                     "/org/qemu/VMState1",
 122                     "org.qemu.VMState1",
 123                     NULL, err);
 124         if (!proxy) {
 125             return NULL;
 126         }
 127
 128         result = g_dbus_proxy_get_cached_property(proxy, "Id");
 129         if (!result) {
 130             g_set_error_literal(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 131                                 "VMState Id property is missing.");
 132             return NULL;
 133         }
 134
 135         id = g_variant_dup_string(result, &size);
 136         if (ids && !g_hash_table_remove(ids, id)) {
 137             g_clear_pointer(&id, g_free);
 138             g_clear_object(&proxy);
 139             continue;
 140         }
 141         if (size == 0 || size >= 256) {
 142             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 143                         "VMState Id '%s' is invalid.", id);
 144             return NULL;
 145         }
 146
 147         if (!g_hash_table_insert(proxies, id, proxy)) {
 148             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 149                         "Duplicated VMState Id '%s'", id);
 150             return NULL;
 151         }
 152         id = NULL;
 153         proxy = NULL;
 154
 155         g_clear_pointer(&result, g_variant_unref);
 156     }
 157
 158     if (ids) {
 159         g_autofree char **left = NULL;
 160
 161         left = (char **)g_hash_table_get_keys_as_array(ids, NULL);
 162         if (*left) {
 163             g_autofree char *leftids = g_strjoinv(",", left);
 164             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 165                         "Required VMState Id are missing: %s", leftids);
 166             return NULL;
 167         }
 168     }
 169
 170     return g_steal_pointer(&proxies);
 171 }
 172
 173 static int
 174 dbus_load_state_proxy(GDBusProxy *proxy, const uint8_t *data, size_t size)
 175 {
 176     g_autoptr(GError) err = NULL;
 177     g_autoptr(GVariant) result = NULL;
 178     g_autoptr(GVariant) value = NULL;
 179
 180     value = g_variant_new_fixed_array(G_VARIANT_TYPE_BYTE,
 181                                       data, size, sizeof(char));
 182     result = g_dbus_proxy_call_sync(proxy, "Load",
 183                                     g_variant_new("(@ay)",
 184                                                   g_steal_pointer(&value)),
 185                                     G_DBUS_CALL_FLAGS_NO_AUTO_START,
 186                                     -1, NULL, &err);
 187     if (!result) {
 188         error_report("%s: Failed to Load: %s", __func__, err->message);
 189         return -1;
 190     }
 191
 192     return 0;
 193 }
 194
 195 static int dbus_vmstate_post_load(void *opaque, int version_id)
 196 {
 197     DBusVMState *self = DBUS_VMSTATE(opaque);
 198     g_autoptr(GInputStream) m = NULL;
 199     g_autoptr(GDataInputStream) s = NULL;
 200     g_autoptr(GError) err = NULL;
 201     g_autoptr(GHashTable) proxies = NULL;
 202     uint32_t nelem;
 203
 204     trace_dbus_vmstate_post_load(version_id);
 205
 206     proxies = dbus_get_proxies(self, &err);
 207     if (!proxies) {
 208         error_report("%s: Failed to get proxies: %s", __func__, err->message);
 209         return -1;
 210     }
 211
 212     m = g_memory_input_stream_new_from_data(self->data, self->data_size, NULL);
 213     s = g_data_input_stream_new(m);
 214     g_data_input_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
 215
 216     nelem = g_data_input_stream_read_uint32(s, NULL, &err);
 217     if (err) {
 218         goto error;
 219     }
 220
 221     while (nelem > 0) {
 222         GDBusProxy *proxy = NULL;
 223         uint32_t len;
 224         gsize bytes_read, avail;
 225         char id[256];
 226
 227         len = g_data_input_stream_read_uint32(s, NULL, &err);
 228         if (err) {
 229             goto error;
 230         }
 231         if (len >= 256) {
 232             error_report("%s: Invalid DBus vmstate proxy name %u",
 233                          __func__, len);
 234             return -1;
 235         }
 236         if (!g_input_stream_read_all(G_INPUT_STREAM(s), id, len,
 237                                      &bytes_read, NULL, &err)) {
 238             goto error;
 239         }
 240         g_return_val_if_fail(bytes_read == len, -1);
 241         id[len] = 0;
 242
 243         trace_dbus_vmstate_loading(id);
 244
 245         proxy = g_hash_table_lookup(proxies, id);
 246         if (!proxy) {
 247             error_report("%s: Failed to find proxy Id '%s'", __func__, id);
 248             return -1;
 249         }
 250
 251         len = g_data_input_stream_read_uint32(s, NULL, &err);
 252         avail = g_buffered_input_stream_get_available(
 253             G_BUFFERED_INPUT_STREAM(s));
 254
 255         if (len > DBUS_VMSTATE_SIZE_LIMIT || len > avail) {
 256             error_report("%s: Invalid vmstate size: %u", __func__, len);
 257             return -1;
 258         }
 259
 260         if (dbus_load_state_proxy(proxy,
 261                 g_buffered_input_stream_peek_buffer(G_BUFFERED_INPUT_STREAM(s),
 262                                                     NULL),
 263                 len) < 0) {
 264             error_report("%s: Failed to restore Id '%s'", __func__, id);
 265             return -1;
 266         }
 267
 268         if (!g_seekable_seek(G_SEEKABLE(s), len, G_SEEK_CUR, NULL, &err)) {
 269             goto error;
 270         }
 271
 272         nelem -= 1;
 273     }
 274
 275     return 0;
 276
 277 error:
 278     error_report("%s: Failed to read from stream: %s", __func__, err->message);
 279     return -1;
 280 }
 281
 282 static void
 283 dbus_save_state_proxy(gpointer key,
 284                       gpointer value,
 285                       gpointer user_data)
 286 {
 287     GDataOutputStream *s = user_data;
 288     const char *id = key;
 289     GDBusProxy *proxy = value;
 290     g_autoptr(GVariant) result = NULL;
 291     g_autoptr(GVariant) child = NULL;
 292     g_autoptr(GError) err = NULL;
 293     const uint8_t *data;
 294     gsize size;
 295
 296     trace_dbus_vmstate_saving(id);
 297
 298     result = g_dbus_proxy_call_sync(proxy, "Save",
 299                                     NULL, G_DBUS_CALL_FLAGS_NO_AUTO_START,
 300                                     -1, NULL, &err);
 301     if (!result) {
 302         error_report("%s: Failed to Save: %s", __func__, err->message);
 303         return;
 304     }
 305
 306     child = g_variant_get_child_value(result, 0);
 307     data = g_variant_get_fixed_array(child, &size, sizeof(char));
 308     if (!data) {
 309         error_report("%s: Failed to Save: not a byte array", __func__);
 310         return;
 311     }
 312     if (size > DBUS_VMSTATE_SIZE_LIMIT) {
 313         error_report("%s: Too large vmstate data to save: %zu",
 314                      __func__, (size_t)size);
 315         return;
 316     }
 317
 318     if (!g_data_output_stream_put_uint32(s, strlen(id), NULL, &err) ||
 319         !g_data_output_stream_put_string(s, id, NULL, &err) ||
 320         !g_data_output_stream_put_uint32(s, size, NULL, &err) ||
 321         !g_output_stream_write_all(G_OUTPUT_STREAM(s),
 322                                    data, size, NULL, NULL, &err)) {
 323         error_report("%s: Failed to write to stream: %s",
 324                      __func__, err->message);
 325     }
 326 }
 327
 328 static int dbus_vmstate_pre_save(void *opaque)
 329 {
 330     DBusVMState *self = DBUS_VMSTATE(opaque);
 331     g_autoptr(GOutputStream) m = NULL;
 332     g_autoptr(GDataOutputStream) s = NULL;
 333     g_autoptr(GHashTable) proxies = NULL;
 334     g_autoptr(GError) err = NULL;
 335
 336     trace_dbus_vmstate_pre_save();
 337
 338     proxies = dbus_get_proxies(self, &err);
 339     if (!proxies) {
 340         error_report("%s: Failed to get proxies: %s", __func__, err->message);
 341         return -1;
 342     }
 343
 344     m = g_memory_output_stream_new_resizable();
 345     s = g_data_output_stream_new(m);
 346     g_data_output_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
 347
 348     if (!g_data_output_stream_put_uint32(s, g_hash_table_size(proxies),
 349                                          NULL, &err)) {
 350         error_report("%s: Failed to write to stream: %s",
 351                      __func__, err->message);
 352         return -1;
 353     }
 354
 355     g_hash_table_foreach(proxies, dbus_save_state_proxy, s);
 356
 357     if (g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m))
 358         > UINT32_MAX) {
 359         error_report("%s: DBus vmstate buffer is too large", __func__);
 360         return -1;
 361     }
 362
 363     if (!g_output_stream_close(G_OUTPUT_STREAM(m), NULL, &err)) {
 364         error_report("%s: Failed to close stream: %s", __func__, err->message);
 365         return -1;
 366     }
 367
 368     g_free(self->data);
 369     self->data_size =
 370         g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m));
 371     self->data =
 372         g_memory_output_stream_steal_data(G_MEMORY_OUTPUT_STREAM(m));
 373
 374     return 0;
 375 }
 376
 377 static const VMStateDescription dbus_vmstate = {
 378     .name = TYPE_DBUS_VMSTATE,
 379     .version_id = 0,
 380     .pre_save = dbus_vmstate_pre_save,
 381     .post_load = dbus_vmstate_post_load,
 382     .fields = (VMStateField[]) {
 383         VMSTATE_UINT32(data_size, DBusVMState),
 384         VMSTATE_VBUFFER_ALLOC_UINT32(data, DBusVMState, 0, 0, data_size),
 385         VMSTATE_END_OF_LIST()
 386     }
 387 };
 388
 389 static void
 390 dbus_vmstate_complete(UserCreatable *uc, Error **errp)
 391 {
 392     DBusVMState *self = DBUS_VMSTATE(uc);
 393     g_autoptr(GError) err = NULL;
 394
 395     if (!object_resolve_path_type("", TYPE_DBUS_VMSTATE, NULL)) {
 396         error_setg(errp, "There is already an instance of %s",
 397                    TYPE_DBUS_VMSTATE);
 398         return;
 399     }
 400
 401     if (!self->dbus_addr) {
 402         error_setg(errp, QERR_MISSING_PARAMETER, "addr");
 403         return;
 404     }
 405
 406     self->bus = g_dbus_connection_new_for_address_sync(self->dbus_addr,
 407                     G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
 408                     G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION,
 409                     NULL, NULL, &err);
 410     if (err) {
 411         error_setg(errp, "failed to connect to DBus: '%s'", err->message);
 412         return;
 413     }
 414
 415     if (vmstate_register(VMSTATE_IF(self), VMSTATE_INSTANCE_ID_ANY,
 416                          &dbus_vmstate, self) < 0) {
 417         error_setg(errp, "Failed to register vmstate");
 418     }
 419 }
 420
 421 static void
 422 dbus_vmstate_finalize(Object *o)
 423 {
 424     DBusVMState *self = DBUS_VMSTATE(o);
 425
 426     vmstate_unregister(VMSTATE_IF(self), &dbus_vmstate, self);
 427
 428     g_clear_object(&self->bus);
 429     g_free(self->dbus_addr);
 430     g_free(self->id_list);
 431     g_free(self->data);
 432 }
 433
 434 static char *
 435 get_dbus_addr(Object *o, Error **errp)
 436 {
 437     DBusVMState *self = DBUS_VMSTATE(o);
 438
 439     return g_strdup(self->dbus_addr);
 440 }
 441
 442 static void
 443 set_dbus_addr(Object *o, const char *str, Error **errp)
 444 {
 445     DBusVMState *self = DBUS_VMSTATE(o);
 446
 447     g_free(self->dbus_addr);
 448     self->dbus_addr = g_strdup(str);
 449 }
 450
 451 static char *
 452 get_id_list(Object *o, Error **errp)
 453 {
 454     DBusVMState *self = DBUS_VMSTATE(o);
 455
 456     return g_strdup(self->id_list);
 457 }
 458
 459 static void
 460 set_id_list(Object *o, const char *str, Error **errp)
 461 {
 462     DBusVMState *self = DBUS_VMSTATE(o);
 463
 464     g_free(self->id_list);
 465     self->id_list = g_strdup(str);
 466 }
 467
 468 static char *
 469 dbus_vmstate_get_id(VMStateIf *vmif)
 470 {
 471     return g_strdup(TYPE_DBUS_VMSTATE);
 472 }
 473
 474 static void
 475 dbus_vmstate_class_init(ObjectClass *oc, void *data)
 476 {
 477     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 478     VMStateIfClass *vc = VMSTATE_IF_CLASS(oc);
 479
 480     ucc->complete = dbus_vmstate_complete;
 481     vc->get_id = dbus_vmstate_get_id;
 482
 483     object_class_property_add_str(oc, "addr",
 484                                   get_dbus_addr, set_dbus_addr,
 485                                   &error_abort);
 486     object_class_property_add_str(oc, "id-list",
 487                                   get_id_list, set_id_list,
 488                                   &error_abort);
 489 }
 490
 491 static const TypeInfo dbus_vmstate_info = {
 492     .name = TYPE_DBUS_VMSTATE,
 493     .parent = TYPE_OBJECT,
 494     .instance_size = sizeof(DBusVMState),
 495     .instance_finalize = dbus_vmstate_finalize,
 496     .class_size = sizeof(DBusVMStateClass),
 497     .class_init = dbus_vmstate_class_init,
 498     .interfaces = (InterfaceInfo[]) {
 499         { TYPE_USER_CREATABLE },
 500         { TYPE_VMSTATE_IF },
 501         { }
 502     }
 503 };
 504
 505 static void
 506 register_types(void)
 507 {
 508     type_register_static(&dbus_vmstate_info);
 509 }
 510
 511 type_init(register_types);