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             return NULL;
 118         }
 119
 120         result = g_dbus_proxy_get_cached_property(proxy, "Id");
 121         if (!result) {
 122             g_set_error_literal(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 123                                 "VMState Id property is missing.");
 124             return NULL;
 125         }
 126
 127         id = g_variant_dup_string(result, &size);
 128         if (ids && !g_hash_table_remove(ids, id)) {
 129             g_clear_pointer(&id, g_free);
 130             g_clear_object(&proxy);
 131             continue;
 132         }
 133         if (size == 0 || size >= 256) {
 134             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 135                         "VMState Id '%s' is invalid.", id);
 136             return NULL;
 137         }
 138
 139         if (!g_hash_table_insert(proxies, id, proxy)) {
 140             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 141                         "Duplicated VMState Id '%s'", id);
 142             return NULL;
 143         }
 144         id = NULL;
 145         proxy = NULL;
 146
 147         g_clear_pointer(&result, g_variant_unref);
 148     }
 149
 150     if (ids) {
 151         g_autofree char **left = NULL;
 152
 153         left = (char **)g_hash_table_get_keys_as_array(ids, NULL);
 154         if (*left) {
 155             g_autofree char *leftids = g_strjoinv(",", left);
 156             g_set_error(err, G_IO_ERROR, G_IO_ERROR_FAILED,
 157                         "Required VMState Id are missing: %s", leftids);
 158             return NULL;
 159         }
 160     }
 161
 162     return g_steal_pointer(&proxies);
 163 }
 164
 165 static int
 166 dbus_load_state_proxy(GDBusProxy *proxy, const uint8_t *data, size_t size)
 167 {
 168     g_autoptr(GError) err = NULL;
 169     g_autoptr(GVariant) result = NULL;
 170     g_autoptr(GVariant) value = NULL;
 171
 172     value = g_variant_new_fixed_array(G_VARIANT_TYPE_BYTE,
 173                                       data, size, sizeof(char));
 174     result = g_dbus_proxy_call_sync(proxy, "Load",
 175                                     g_variant_new("(@ay)",
 176                                                   g_steal_pointer(&value)),
 177                                     G_DBUS_CALL_FLAGS_NO_AUTO_START,
 178                                     -1, NULL, &err);
 179     if (!result) {
 180         error_report("%s: Failed to Load: %s", __func__, err->message);
 181         return -1;
 182     }
 183
 184     return 0;
 185 }
 186
 187 static int dbus_vmstate_post_load(void *opaque, int version_id)
 188 {
 189     DBusVMState *self = DBUS_VMSTATE(opaque);
 190     g_autoptr(GInputStream) m = NULL;
 191     g_autoptr(GDataInputStream) s = NULL;
 192     g_autoptr(GError) err = NULL;
 193     g_autoptr(GHashTable) proxies = NULL;
 194     uint32_t nelem;
 195
 196     trace_dbus_vmstate_post_load(version_id);
 197
 198     proxies = dbus_get_proxies(self, &err);
 199     if (!proxies) {
 200         error_report("%s: Failed to get proxies: %s", __func__, err->message);
 201         return -1;
 202     }
 203
 204     m = g_memory_input_stream_new_from_data(self->data, self->data_size, NULL);
 205     s = g_data_input_stream_new(m);
 206     g_data_input_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
 207
 208     nelem = g_data_input_stream_read_uint32(s, NULL, &err);
 209     if (err) {
 210         goto error;
 211     }
 212
 213     while (nelem > 0) {
 214         GDBusProxy *proxy = NULL;
 215         uint32_t len;
 216         gsize bytes_read, avail;
 217         char id[256];
 218
 219         len = g_data_input_stream_read_uint32(s, NULL, &err);
 220         if (err) {
 221             goto error;
 222         }
 223         if (len >= 256) {
 224             error_report("%s: Invalid DBus vmstate proxy name %u",
 225                          __func__, len);
 226             return -1;
 227         }
 228         if (!g_input_stream_read_all(G_INPUT_STREAM(s), id, len,
 229                                      &bytes_read, NULL, &err)) {
 230             goto error;
 231         }
 232         if (bytes_read != len) {
 233             error_report("%s: Short read", __func__);
 234             return -1;
 235         }
 236         id[len] = 0;
 237
 238         trace_dbus_vmstate_loading(id);
 239
 240         proxy = g_hash_table_lookup(proxies, id);
 241         if (!proxy) {
 242             error_report("%s: Failed to find proxy Id '%s'", __func__, id);
 243             return -1;
 244         }
 245
 246         len = g_data_input_stream_read_uint32(s, NULL, &err);
 247         avail = g_buffered_input_stream_get_available(
 248             G_BUFFERED_INPUT_STREAM(s));
 249
 250         if (len > DBUS_VMSTATE_SIZE_LIMIT || len > avail) {
 251             error_report("%s: Invalid vmstate size: %u", __func__, len);
 252             return -1;
 253         }
 254
 255         if (dbus_load_state_proxy(proxy,
 256                 g_buffered_input_stream_peek_buffer(G_BUFFERED_INPUT_STREAM(s),
 257                                                     NULL),
 258                 len) < 0) {
 259             error_report("%s: Failed to restore Id '%s'", __func__, id);
 260             return -1;
 261         }
 262
 263         if (!g_seekable_seek(G_SEEKABLE(s), len, G_SEEK_CUR, NULL, &err)) {
 264             goto error;
 265         }
 266
 267         nelem -= 1;
 268     }
 269
 270     return 0;
 271
 272 error:
 273     error_report("%s: Failed to read from stream: %s", __func__, err->message);
 274     return -1;
 275 }
 276
 277 static void
 278 dbus_save_state_proxy(gpointer key,
 279                       gpointer value,
 280                       gpointer user_data)
 281 {
 282     GDataOutputStream *s = user_data;
 283     const char *id = key;
 284     GDBusProxy *proxy = value;
 285     g_autoptr(GVariant) result = NULL;
 286     g_autoptr(GVariant) child = NULL;
 287     g_autoptr(GError) err = NULL;
 288     const uint8_t *data;
 289     gsize size;
 290
 291     trace_dbus_vmstate_saving(id);
 292
 293     result = g_dbus_proxy_call_sync(proxy, "Save",
 294                                     NULL, G_DBUS_CALL_FLAGS_NO_AUTO_START,
 295                                     -1, NULL, &err);
 296     if (!result) {
 297         error_report("%s: Failed to Save: %s", __func__, err->message);
 298         return;
 299     }
 300
 301     child = g_variant_get_child_value(result, 0);
 302     data = g_variant_get_fixed_array(child, &size, sizeof(char));
 303     if (!data) {
 304         error_report("%s: Failed to Save: not a byte array", __func__);
 305         return;
 306     }
 307     if (size > DBUS_VMSTATE_SIZE_LIMIT) {
 308         error_report("%s: Too large vmstate data to save: %zu",
 309                      __func__, (size_t)size);
 310         return;
 311     }
 312
 313     if (!g_data_output_stream_put_uint32(s, strlen(id), NULL, &err) ||
 314         !g_data_output_stream_put_string(s, id, NULL, &err) ||
 315         !g_data_output_stream_put_uint32(s, size, NULL, &err) ||
 316         !g_output_stream_write_all(G_OUTPUT_STREAM(s),
 317                                    data, size, NULL, NULL, &err)) {
 318         error_report("%s: Failed to write to stream: %s",
 319                      __func__, err->message);
 320     }
 321 }
 322
 323 static int dbus_vmstate_pre_save(void *opaque)
 324 {
 325     DBusVMState *self = DBUS_VMSTATE(opaque);
 326     g_autoptr(GOutputStream) m = NULL;
 327     g_autoptr(GDataOutputStream) s = NULL;
 328     g_autoptr(GHashTable) proxies = NULL;
 329     g_autoptr(GError) err = NULL;
 330
 331     trace_dbus_vmstate_pre_save();
 332
 333     proxies = dbus_get_proxies(self, &err);
 334     if (!proxies) {
 335         error_report("%s: Failed to get proxies: %s", __func__, err->message);
 336         return -1;
 337     }
 338
 339     m = g_memory_output_stream_new_resizable();
 340     s = g_data_output_stream_new(m);
 341     g_data_output_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
 342
 343     if (!g_data_output_stream_put_uint32(s, g_hash_table_size(proxies),
 344                                          NULL, &err)) {
 345         error_report("%s: Failed to write to stream: %s",
 346                      __func__, err->message);
 347         return -1;
 348     }
 349
 350     g_hash_table_foreach(proxies, dbus_save_state_proxy, s);
 351
 352     if (g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m))
 353         > UINT32_MAX) {
 354         error_report("%s: DBus vmstate buffer is too large", __func__);
 355         return -1;
 356     }
 357
 358     if (!g_output_stream_close(G_OUTPUT_STREAM(m), NULL, &err)) {
 359         error_report("%s: Failed to close stream: %s", __func__, err->message);
 360         return -1;
 361     }
 362
 363     g_free(self->data);
 364     self->data_size =
 365         g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m));
 366     self->data =
 367         g_memory_output_stream_steal_data(G_MEMORY_OUTPUT_STREAM(m));
 368
 369     return 0;
 370 }
 371
 372 static const VMStateDescription dbus_vmstate = {
 373     .name = TYPE_DBUS_VMSTATE,
 374     .version_id = 0,
 375     .pre_save = dbus_vmstate_pre_save,
 376     .post_load = dbus_vmstate_post_load,
 377     .fields = (VMStateField[]) {
 378         VMSTATE_UINT32(data_size, DBusVMState),
 379         VMSTATE_VBUFFER_ALLOC_UINT32(data, DBusVMState, 0, 0, data_size),
 380         VMSTATE_END_OF_LIST()
 381     }
 382 };
 383
 384 static void
 385 dbus_vmstate_complete(UserCreatable *uc, Error **errp)
 386 {
 387     DBusVMState *self = DBUS_VMSTATE(uc);
 388     g_autoptr(GError) err = NULL;
 389
 390     if (!object_resolve_path_type("", TYPE_DBUS_VMSTATE, NULL)) {
 391         error_setg(errp, "There is already an instance of %s",
 392                    TYPE_DBUS_VMSTATE);
 393         return;
 394     }
 395
 396     if (!self->dbus_addr) {
 397         error_setg(errp, QERR_MISSING_PARAMETER, "addr");
 398         return;
 399     }
 400
 401     self->bus = g_dbus_connection_new_for_address_sync(self->dbus_addr,
 402                     G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
 403                     G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION,
 404                     NULL, NULL, &err);
 405     if (err) {
 406         error_setg(errp, "failed to connect to DBus: '%s'", err->message);
 407         return;
 408     }
 409
 410     if (vmstate_register(VMSTATE_IF(self), VMSTATE_INSTANCE_ID_ANY,
 411                          &dbus_vmstate, self) < 0) {
 412         error_setg(errp, "Failed to register vmstate");
 413     }
 414 }
 415
 416 static void
 417 dbus_vmstate_finalize(Object *o)
 418 {
 419     DBusVMState *self = DBUS_VMSTATE(o);
 420
 421     vmstate_unregister(VMSTATE_IF(self), &dbus_vmstate, self);
 422
 423     g_clear_object(&self->bus);
 424     g_free(self->dbus_addr);
 425     g_free(self->id_list);
 426     g_free(self->data);
 427 }
 428
 429 static char *
 430 get_dbus_addr(Object *o, Error **errp)
 431 {
 432     DBusVMState *self = DBUS_VMSTATE(o);
 433
 434     return g_strdup(self->dbus_addr);
 435 }
 436
 437 static void
 438 set_dbus_addr(Object *o, const char *str, Error **errp)
 439 {
 440     DBusVMState *self = DBUS_VMSTATE(o);
 441
 442     g_free(self->dbus_addr);
 443     self->dbus_addr = g_strdup(str);
 444 }
 445
 446 static char *
 447 get_id_list(Object *o, Error **errp)
 448 {
 449     DBusVMState *self = DBUS_VMSTATE(o);
 450
 451     return g_strdup(self->id_list);
 452 }
 453
 454 static void
 455 set_id_list(Object *o, const char *str, Error **errp)
 456 {
 457     DBusVMState *self = DBUS_VMSTATE(o);
 458
 459     g_free(self->id_list);
 460     self->id_list = g_strdup(str);
 461 }
 462
 463 static char *
 464 dbus_vmstate_get_id(VMStateIf *vmif)
 465 {
 466     return g_strdup(TYPE_DBUS_VMSTATE);
 467 }
 468
 469 static void
 470 dbus_vmstate_class_init(ObjectClass *oc, void *data)
 471 {
 472     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 473     VMStateIfClass *vc = VMSTATE_IF_CLASS(oc);
 474
 475     ucc->complete = dbus_vmstate_complete;
 476     vc->get_id = dbus_vmstate_get_id;
 477
 478     object_class_property_add_str(oc, "addr",
 479                                   get_dbus_addr, set_dbus_addr);
 480     object_class_property_add_str(oc, "id-list",
 481                                   get_id_list, set_id_list);
 482 }
 483
 484 static const TypeInfo dbus_vmstate_info = {
 485     .name = TYPE_DBUS_VMSTATE,
 486     .parent = TYPE_OBJECT,
 487     .instance_size = sizeof(DBusVMState),
 488     .instance_finalize = dbus_vmstate_finalize,
 489     .class_init = dbus_vmstate_class_init,
 490     .interfaces = (InterfaceInfo[]) {
 491         { TYPE_USER_CREATABLE },
 492         { TYPE_VMSTATE_IF },
 493         { }
 494     }
 495 };
 496
 497 static void
 498 register_types(void)
 499 {
 500     type_register_static(&dbus_vmstate_info);
 501 }
 502
 503 type_init(register_types);