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 #include "qom/object.h"
  23
  24
  25 #define TYPE_DBUS_VMSTATE "dbus-vmstate"
  26 OBJECT_DECLARE_SIMPLE_TYPE(DBusVMState,
  27                            DBUS_VMSTATE)
  28
  29
  30 struct DBusVMState {
  31     Object parent;
  32
  33     GDBusConnection *bus;
  34     char *dbus_addr;
  35     char *id_list;
  36
  37     uint32_t data_size;
  38     uint8_t *data;
  39 };
  40
  41 static const GDBusPropertyInfo vmstate_property_info[] = {
  42     { -1, (char *) "Id", (char *) "s",
  43       G_DBUS_PROPERTY_INFO_FLAGS_READABLE, NULL },
  44 };
  45
  46 static const GDBusPropertyInfo * const vmstate_property_info_pointers[] = {
  47     &vmstate_property_info[0],
  48     NULL
  49 };
  50
  51 static const GDBusInterfaceInfo vmstate1_interface_info = {
  52     -1,
  53     (char *) "org.qemu.VMState1",
  54     (GDBusMethodInfo **) NULL,
  55     (GDBusSignalInfo **) NULL,
  56     (GDBusPropertyInfo **) &vmstate_property_info_pointers,
  57     NULL,
  58 };
  59
  60 #define DBUS_VMSTATE_SIZE_LIMIT (1 * MiB)
  61
  62 static GHashTable *
  63 get_id_list_set(DBusVMState *self)
  64 {
  65     g_auto(GStrv) ids = NULL;
  66     g_autoptr(GHashTable) set = NULL;
  67     int i;
  68
  69     if (!self->id_list) {
  70         return NULL;
  71     }
  72
  73     ids = g_strsplit(self->id_list, ",", -1);
  74     set = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, NULL);
  75     for (i = 0; ids[i]; i++) {
  76         g_hash_table_add(set, ids[i]);
  77         ids[i] = NULL;
  78     }
  79
  80     return g_steal_pointer(&set);
  81 }
  82
  83 static GHashTable *
  84 dbus_get_proxies(DBusVMState *self, GError **err)
  85 {
  86     g_autoptr(GHashTable) proxies = NULL;
  87     g_autoptr(GHashTable) ids = NULL;
  88     g_auto(GStrv) names = NULL;
  89     Error *error = NULL;
  90     size_t i;
  91
  92     ids = get_id_list_set(self);
  93     proxies = g_hash_table_new_full(g_str_hash, g_str_equal,
  94                                     g_free, g_object_unref);
  95
  96     names = qemu_dbus_get_queued_owners(self->bus, "org.qemu.VMState1", &error);
  97     if (!names) {
  98         g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED, "%s",
  99                     error_get_pretty(error));
 100         error_free(error);
 101         return NULL;
 102     }
 103
 104     for (i = 0; names[i]; i++) {
 105         g_autoptr(GDBusProxy) proxy = NULL;
 106         g_autoptr(GVariant) result = NULL;
 107         g_autofree char *id = NULL;
 108         size_t size;
 109
 110         proxy = g_dbus_proxy_new_sync(self->bus, G_DBUS_PROXY_FLAGS_NONE,
 111                     (GDBusInterfaceInfo *) &vmstate1_interface_info,
 112                     names[i],
 113                     "/org/qemu/VMState1",
 114                     "org.qemu.VMState1",
 115                     NULL, err);
 116         if (!proxy) {
 117             if (err != NULL && *err != NULL) {
 118                 warn_report("%s: Failed to create proxy: %s",
 119                             __func__, (*err)->message);
 120                 g_clear_error(err);
 121             }
 122             continue;
 123         }
 124
 125         result = g_dbus_proxy_get_cached_property(proxy, "Id");
 126         if (!result) {
 127             warn_report("%s: VMState Id property is missing.", __func__);
 128             g_clear_object(&proxy);
 129             continue;
 130         }
 131
 132         id = g_variant_dup_string(result, &size);
 133         if (ids && !g_hash_table_remove(ids, id)) {
 134             g_clear_pointer(&id, g_free);
 135             g_clear_object(&proxy);
 136             continue;
 137         }
 138         if (size == 0 || size >= 256) {
 139             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 140                         "VMState Id '%s' is invalid.", id);
 141             return NULL;
 142         }
 143
 144         if (!g_hash_table_insert(proxies, id, proxy)) {
 145             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 146                         "Duplicated VMState Id '%s'", id);
 147             return NULL;
 148         }
 149         id = NULL;
 150         proxy = NULL;
 151
 152         g_clear_pointer(&result, g_variant_unref);
 153     }
 154
 155     if (ids) {
 156         g_autofree char **left = NULL;
 157
 158         left = (char **)g_hash_table_get_keys_as_array(ids, NULL);
 159         if (*left) {
 160             g_autofree char *leftids = g_strjoinv(",", left);
 161             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 162                         "Required VMState Id are missing: %s", leftids);
 163             return NULL;
 164         }
 165     }
 166
 167     return g_steal_pointer(&proxies);
 168 }
 169
 170 static int
 171 dbus_load_state_proxy(GDBusProxy *proxy, const uint8_t *data, size_t size)
 172 {
 173     g_autoptr(GError) err = NULL;
 174     g_autoptr(GVariant) result = NULL;
 175     g_autoptr(GVariant) value = NULL;
 176
 177     value = g_variant_new_fixed_array(G_VARIANT_TYPE_BYTE,
 178                                       data, size, sizeof(char));
 179     result = g_dbus_proxy_call_sync(proxy, "Load",
 180                                     g_variant_new("(@ay)",
 181                                                   g_steal_pointer(&value)),
 182                                     G_DBUS_CALL_FLAGS_NO_AUTO_START,
 183                                     -1, NULL, &err);
 184     if (!result) {
 185         error_report("%s: Failed to Load: %s", __func__, err->message);
 186         return -1;
 187     }
 188
 189     return 0;
 190 }
 191
 192 static int dbus_vmstate_post_load(void *opaque, int version_id)
 193 {
 194     DBusVMState *self = DBUS_VMSTATE(opaque);
 195     g_autoptr(GInputStream) m = NULL;
 196     g_autoptr(GDataInputStream) s = NULL;
 197     g_autoptr(GError) err = NULL;
 198     g_autoptr(GHashTable) proxies = NULL;
 199     uint32_t nelem;
 200
 201     trace_dbus_vmstate_post_load(version_id);
 202
 203     proxies = dbus_get_proxies(self, &err);
 204     if (!proxies) {
 205         error_report("%s: Failed to get proxies: %s", __func__, err->message);
 206         return -1;
 207     }
 208
 209     m = g_memory_input_stream_new_from_data(self->data, self->data_size, NULL);
 210     s = g_data_input_stream_new(m);
 211     g_data_input_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
 212     g_buffered_input_stream_set_buffer_size(G_BUFFERED_INPUT_STREAM(s),
 213                                             DBUS_VMSTATE_SIZE_LIMIT);
 214
 215     nelem = g_data_input_stream_read_uint32(s, NULL, &err);
 216     if (err) {
 217         goto error;
 218     }
 219
 220     while (nelem > 0) {
 221         GDBusProxy *proxy = NULL;
 222         uint32_t len;
 223         gsize bytes_read, avail;
 224         char id[256];
 225
 226         len = g_data_input_stream_read_uint32(s, NULL, &err);
 227         if (err) {
 228             goto error;
 229         }
 230         if (len >= 256) {
 231             error_report("%s: Invalid DBus vmstate proxy name %u",
 232                          __func__, len);
 233             return -1;
 234         }
 235         if (!g_input_stream_read_all(G_INPUT_STREAM(s), id, len,
 236                                      &bytes_read, NULL, &err)) {
 237             goto error;
 238         }
 239         if (bytes_read != len) {
 240             error_report("%s: Short read", __func__);
 241             return -1;
 242         }
 243         id[len] = 0;
 244
 245         trace_dbus_vmstate_loading(id);
 246
 247         proxy = g_hash_table_lookup(proxies, id);
 248         if (!proxy) {
 249             error_report("%s: Failed to find proxy Id '%s'", __func__, id);
 250             return -1;
 251         }
 252
 253         len = g_data_input_stream_read_uint32(s, NULL, &err);
 254         if (len > DBUS_VMSTATE_SIZE_LIMIT) {
 255             error_report("%s: Invalid vmstate size: %u", __func__, len);
 256             return -1;
 257         }
 258
 259         g_buffered_input_stream_fill(G_BUFFERED_INPUT_STREAM(s), len, NULL,
 260                                      &err);
 261         if (err) {
 262             goto error;
 263         }
 264
 265         avail = g_buffered_input_stream_get_available(
 266             G_BUFFERED_INPUT_STREAM(s));
 267         if (len > avail) {
 268             error_report("%s: Not enough data available to load for Id: '%s'. "
 269                 "Available data size: %zu, Actual vmstate size: %u",
 270                 __func__, id, avail, len);
 271             return -1;
 272         }
 273
 274         if (dbus_load_state_proxy(proxy,
 275                 g_buffered_input_stream_peek_buffer(G_BUFFERED_INPUT_STREAM(s),
 276                                                     NULL),
 277                 len) < 0) {
 278             error_report("%s: Failed to restore Id '%s'", __func__, id);
 279             return -1;
 280         }
 281
 282         if (!g_seekable_seek(G_SEEKABLE(s), len, G_SEEK_CUR, NULL, &err)) {
 283             goto error;
 284         }
 285
 286         nelem -= 1;
 287     }
 288
 289     return 0;
 290
 291 error:
 292     error_report("%s: Failed to read from stream: %s", __func__, err->message);
 293     return -1;
 294 }
 295
 296 static void
 297 dbus_save_state_proxy(gpointer key,
 298                       gpointer value,
 299                       gpointer user_data)
 300 {
 301     GDataOutputStream *s = user_data;
 302     const char *id = key;
 303     GDBusProxy *proxy = value;
 304     g_autoptr(GVariant) result = NULL;
 305     g_autoptr(GVariant) child = NULL;
 306     g_autoptr(GError) err = NULL;
 307     const uint8_t *data;
 308     gsize size;
 309
 310     trace_dbus_vmstate_saving(id);
 311
 312     result = g_dbus_proxy_call_sync(proxy, "Save",
 313                                     NULL, G_DBUS_CALL_FLAGS_NO_AUTO_START,
 314                                     -1, NULL, &err);
 315     if (!result) {
 316         error_report("%s: Failed to Save: %s", __func__, err->message);
 317         return;
 318     }
 319
 320     child = g_variant_get_child_value(result, 0);
 321     data = g_variant_get_fixed_array(child, &size, sizeof(char));
 322     if (!data) {
 323         error_report("%s: Failed to Save: not a byte array", __func__);
 324         return;
 325     }
 326     if (size > DBUS_VMSTATE_SIZE_LIMIT) {
 327         error_report("%s: Too large vmstate data to save: %zu",
 328                      __func__, (size_t)size);
 329         return;
 330     }
 331
 332     if (!g_data_output_stream_put_uint32(s, strlen(id), NULL, &err) ||
 333         !g_data_output_stream_put_string(s, id, NULL, &err) ||
 334         !g_data_output_stream_put_uint32(s, size, NULL, &err) ||
 335         !g_output_stream_write_all(G_OUTPUT_STREAM(s),
 336                                    data, size, NULL, NULL, &err)) {
 337         error_report("%s: Failed to write to stream: %s",
 338                      __func__, err->message);
 339     }
 340 }
 341
 342 static int dbus_vmstate_pre_save(void *opaque)
 343 {
 344     DBusVMState *self = DBUS_VMSTATE(opaque);
 345     g_autoptr(GOutputStream) m = NULL;
 346     g_autoptr(GDataOutputStream) s = NULL;
 347     g_autoptr(GHashTable) proxies = NULL;
 348     g_autoptr(GError) err = NULL;
 349
 350     trace_dbus_vmstate_pre_save();
 351
 352     proxies = dbus_get_proxies(self, &err);
 353     if (!proxies) {
 354         error_report("%s: Failed to get proxies: %s", __func__, err->message);
 355         return -1;
 356     }
 357
 358     m = g_memory_output_stream_new_resizable();
 359     s = g_data_output_stream_new(m);
 360     g_data_output_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
 361
 362     if (!g_data_output_stream_put_uint32(s, g_hash_table_size(proxies),
 363                                          NULL, &err)) {
 364         error_report("%s: Failed to write to stream: %s",
 365                      __func__, err->message);
 366         return -1;
 367     }
 368
 369     g_hash_table_foreach(proxies, dbus_save_state_proxy, s);
 370
 371     if (g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m))
 372         > UINT32_MAX) {
 373         error_report("%s: DBus vmstate buffer is too large", __func__);
 374         return -1;
 375     }
 376
 377     if (!g_output_stream_close(G_OUTPUT_STREAM(m), NULL, &err)) {
 378         error_report("%s: Failed to close stream: %s", __func__, err->message);
 379         return -1;
 380     }
 381
 382     g_free(self->data);
 383     self->data_size =
 384         g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m));
 385     self->data =
 386         g_memory_output_stream_steal_data(G_MEMORY_OUTPUT_STREAM(m));
 387
 388     return 0;
 389 }
 390
 391 static const VMStateDescription dbus_vmstate = {
 392     .name = TYPE_DBUS_VMSTATE,
 393     .version_id = 0,
 394     .pre_save = dbus_vmstate_pre_save,
 395     .post_load = dbus_vmstate_post_load,
 396     .fields = (VMStateField[]) {
 397         VMSTATE_UINT32(data_size, DBusVMState),
 398         VMSTATE_VBUFFER_ALLOC_UINT32(data, DBusVMState, 0, 0, data_size),
 399         VMSTATE_END_OF_LIST()
 400     }
 401 };
 402
 403 static void
 404 dbus_vmstate_complete(UserCreatable *uc, Error **errp)
 405 {
 406     DBusVMState *self = DBUS_VMSTATE(uc);
 407     g_autoptr(GError) err = NULL;
 408
 409     if (!object_resolve_path_type("", TYPE_DBUS_VMSTATE, NULL)) {
 410         error_setg(errp, "There is already an instance of %s",
 411                    TYPE_DBUS_VMSTATE);
 412         return;
 413     }
 414
 415     if (!self->dbus_addr) {
 416         error_setg(errp, QERR_MISSING_PARAMETER, "addr");
 417         return;
 418     }
 419
 420     self->bus = g_dbus_connection_new_for_address_sync(self->dbus_addr,
 421                     G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
 422                     G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION,
 423                     NULL, NULL, &err);
 424     if (err) {
 425         error_setg(errp, "failed to connect to DBus: '%s'", err->message);
 426         return;
 427     }
 428
 429     if (vmstate_register(VMSTATE_IF(self), VMSTATE_INSTANCE_ID_ANY,
 430                          &dbus_vmstate, self) < 0) {
 431         error_setg(errp, "Failed to register vmstate");
 432     }
 433 }
 434
 435 static void
 436 dbus_vmstate_finalize(Object *o)
 437 {
 438     DBusVMState *self = DBUS_VMSTATE(o);
 439
 440     vmstate_unregister(VMSTATE_IF(self), &dbus_vmstate, self);
 441
 442     g_clear_object(&self->bus);
 443     g_free(self->dbus_addr);
 444     g_free(self->id_list);
 445     g_free(self->data);
 446 }
 447
 448 static char *
 449 get_dbus_addr(Object *o, Error **errp)
 450 {
 451     DBusVMState *self = DBUS_VMSTATE(o);
 452
 453     return g_strdup(self->dbus_addr);
 454 }
 455
 456 static void
 457 set_dbus_addr(Object *o, const char *str, Error **errp)
 458 {
 459     DBusVMState *self = DBUS_VMSTATE(o);
 460
 461     g_free(self->dbus_addr);
 462     self->dbus_addr = g_strdup(str);
 463 }
 464
 465 static char *
 466 get_id_list(Object *o, Error **errp)
 467 {
 468     DBusVMState *self = DBUS_VMSTATE(o);
 469
 470     return g_strdup(self->id_list);
 471 }
 472
 473 static void
 474 set_id_list(Object *o, const char *str, Error **errp)
 475 {
 476     DBusVMState *self = DBUS_VMSTATE(o);
 477
 478     g_free(self->id_list);
 479     self->id_list = g_strdup(str);
 480 }
 481
 482 static char *
 483 dbus_vmstate_get_id(VMStateIf *vmif)
 484 {
 485     return g_strdup(TYPE_DBUS_VMSTATE);
 486 }
 487
 488 static void
 489 dbus_vmstate_class_init(ObjectClass *oc, void *data)
 490 {
 491     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 492     VMStateIfClass *vc = VMSTATE_IF_CLASS(oc);
 493
 494     ucc->complete = dbus_vmstate_complete;
 495     vc->get_id = dbus_vmstate_get_id;
 496
 497     object_class_property_add_str(oc, "addr",
 498                                   get_dbus_addr, set_dbus_addr);
 499     object_class_property_add_str(oc, "id-list",
 500                                   get_id_list, set_id_list);
 501 }
 502
 503 static const TypeInfo dbus_vmstate_info = {
 504     .name = TYPE_DBUS_VMSTATE,
 505     .parent = TYPE_OBJECT,
 506     .instance_size = sizeof(DBusVMState),
 507     .instance_finalize = dbus_vmstate_finalize,
 508     .class_init = dbus_vmstate_class_init,
 509     .interfaces = (InterfaceInfo[]) {
 510         { TYPE_USER_CREATABLE },
 511         { TYPE_VMSTATE_IF },
 512         { }
 513     }
 514 };
 515
 516 static void
 517 register_types(void)
 518 {
 519     type_register_static(&dbus_vmstate_info);
 520 }
 521
 522 type_init(register_types);