xref: /qemu/backends/dbus-vmstate.c (revision 727385c4) 
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     g_buffered_input_stream_set_buffer_size(G_BUFFERED_INPUT_STREAM(s),
208                                             DBUS_VMSTATE_SIZE_LIMIT);
209 
210     nelem = g_data_input_stream_read_uint32(s, NULL, &err);
211     if (err) {
212         goto error;
213     }
214 
215     while (nelem > 0) {
216         GDBusProxy *proxy = NULL;
217         uint32_t len;
218         gsize bytes_read, avail;
219         char id[256];
220 
221         len = g_data_input_stream_read_uint32(s, NULL, &err);
222         if (err) {
223             goto error;
224         }
225         if (len >= 256) {
226             error_report("%s: Invalid DBus vmstate proxy name %u",
227                          __func__, len);
228             return -1;
229         }
230         if (!g_input_stream_read_all(G_INPUT_STREAM(s), id, len,
231                                      &bytes_read, NULL, &err)) {
232             goto error;
233         }
234         if (bytes_read != len) {
235             error_report("%s: Short read", __func__);
236             return -1;
237         }
238         id[len] = 0;
239 
240         trace_dbus_vmstate_loading(id);
241 
242         proxy = g_hash_table_lookup(proxies, id);
243         if (!proxy) {
244             error_report("%s: Failed to find proxy Id '%s'", __func__, id);
245             return -1;
246         }
247 
248         len = g_data_input_stream_read_uint32(s, NULL, &err);
249         if (len > DBUS_VMSTATE_SIZE_LIMIT) {
250             error_report("%s: Invalid vmstate size: %u", __func__, len);
251             return -1;
252         }
253 
254         g_buffered_input_stream_fill(G_BUFFERED_INPUT_STREAM(s), len, NULL,
255                                      &err);
256         if (err) {
257             goto error;
258         }
259 
260         avail = g_buffered_input_stream_get_available(
261             G_BUFFERED_INPUT_STREAM(s));
262         if (len > avail) {
263             error_report("%s: Not enough data available to load for Id: '%s'. "
264                 "Available data size: %zu, Actual vmstate size: %u",
265                 __func__, id, avail, len);
266             return -1;
267         }
268 
269         if (dbus_load_state_proxy(proxy,
270                 g_buffered_input_stream_peek_buffer(G_BUFFERED_INPUT_STREAM(s),
271                                                     NULL),
272                 len) < 0) {
273             error_report("%s: Failed to restore Id '%s'", __func__, id);
274             return -1;
275         }
276 
277         if (!g_seekable_seek(G_SEEKABLE(s), len, G_SEEK_CUR, NULL, &err)) {
278             goto error;
279         }
280 
281         nelem -= 1;
282     }
283 
284     return 0;
285 
286 error:
287     error_report("%s: Failed to read from stream: %s", __func__, err->message);
288     return -1;
289 }
290 
291 static void
292 dbus_save_state_proxy(gpointer key,
293                       gpointer value,
294                       gpointer user_data)
295 {
296     GDataOutputStream *s = user_data;
297     const char *id = key;
298     GDBusProxy *proxy = value;
299     g_autoptr(GVariant) result = NULL;
300     g_autoptr(GVariant) child = NULL;
301     g_autoptr(GError) err = NULL;
302     const uint8_t *data;
303     gsize size;
304 
305     trace_dbus_vmstate_saving(id);
306 
307     result = g_dbus_proxy_call_sync(proxy, "Save",
308                                     NULL, G_DBUS_CALL_FLAGS_NO_AUTO_START,
309                                     -1, NULL, &err);
310     if (!result) {
311         error_report("%s: Failed to Save: %s", __func__, err->message);
312         return;
313     }
314 
315     child = g_variant_get_child_value(result, 0);
316     data = g_variant_get_fixed_array(child, &size, sizeof(char));
317     if (!data) {
318         error_report("%s: Failed to Save: not a byte array", __func__);
319         return;
320     }
321     if (size > DBUS_VMSTATE_SIZE_LIMIT) {
322         error_report("%s: Too large vmstate data to save: %zu",
323                      __func__, (size_t)size);
324         return;
325     }
326 
327     if (!g_data_output_stream_put_uint32(s, strlen(id), NULL, &err) ||
328         !g_data_output_stream_put_string(s, id, NULL, &err) ||
329         !g_data_output_stream_put_uint32(s, size, NULL, &err) ||
330         !g_output_stream_write_all(G_OUTPUT_STREAM(s),
331                                    data, size, NULL, NULL, &err)) {
332         error_report("%s: Failed to write to stream: %s",
333                      __func__, err->message);
334     }
335 }
336 
337 static int dbus_vmstate_pre_save(void *opaque)
338 {
339     DBusVMState *self = DBUS_VMSTATE(opaque);
340     g_autoptr(GOutputStream) m = NULL;
341     g_autoptr(GDataOutputStream) s = NULL;
342     g_autoptr(GHashTable) proxies = NULL;
343     g_autoptr(GError) err = NULL;
344 
345     trace_dbus_vmstate_pre_save();
346 
347     proxies = dbus_get_proxies(self, &err);
348     if (!proxies) {
349         error_report("%s: Failed to get proxies: %s", __func__, err->message);
350         return -1;
351     }
352 
353     m = g_memory_output_stream_new_resizable();
354     s = g_data_output_stream_new(m);
355     g_data_output_stream_set_byte_order(s, G_DATA_STREAM_BYTE_ORDER_BIG_ENDIAN);
356 
357     if (!g_data_output_stream_put_uint32(s, g_hash_table_size(proxies),
358                                          NULL, &err)) {
359         error_report("%s: Failed to write to stream: %s",
360                      __func__, err->message);
361         return -1;
362     }
363 
364     g_hash_table_foreach(proxies, dbus_save_state_proxy, s);
365 
366     if (g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m))
367         > UINT32_MAX) {
368         error_report("%s: DBus vmstate buffer is too large", __func__);
369         return -1;
370     }
371 
372     if (!g_output_stream_close(G_OUTPUT_STREAM(m), NULL, &err)) {
373         error_report("%s: Failed to close stream: %s", __func__, err->message);
374         return -1;
375     }
376 
377     g_free(self->data);
378     self->data_size =
379         g_memory_output_stream_get_size(G_MEMORY_OUTPUT_STREAM(m));
380     self->data =
381         g_memory_output_stream_steal_data(G_MEMORY_OUTPUT_STREAM(m));
382 
383     return 0;
384 }
385 
386 static const VMStateDescription dbus_vmstate = {
387     .name = TYPE_DBUS_VMSTATE,
388     .version_id = 0,
389     .pre_save = dbus_vmstate_pre_save,
390     .post_load = dbus_vmstate_post_load,
391     .fields = (VMStateField[]) {
392         VMSTATE_UINT32(data_size, DBusVMState),
393         VMSTATE_VBUFFER_ALLOC_UINT32(data, DBusVMState, 0, 0, data_size),
394         VMSTATE_END_OF_LIST()
395     }
396 };
397 
398 static void
399 dbus_vmstate_complete(UserCreatable *uc, Error **errp)
400 {
401     DBusVMState *self = DBUS_VMSTATE(uc);
402     g_autoptr(GError) err = NULL;
403 
404     if (!object_resolve_path_type("", TYPE_DBUS_VMSTATE, NULL)) {
405         error_setg(errp, "There is already an instance of %s",
406                    TYPE_DBUS_VMSTATE);
407         return;
408     }
409 
410     if (!self->dbus_addr) {
411         error_setg(errp, QERR_MISSING_PARAMETER, "addr");
412         return;
413     }
414 
415     self->bus = g_dbus_connection_new_for_address_sync(self->dbus_addr,
416                     G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT |
417                     G_DBUS_CONNECTION_FLAGS_MESSAGE_BUS_CONNECTION,
418                     NULL, NULL, &err);
419     if (err) {
420         error_setg(errp, "failed to connect to DBus: '%s'", err->message);
421         return;
422     }
423 
424     if (vmstate_register(VMSTATE_IF(self), VMSTATE_INSTANCE_ID_ANY,
425                          &dbus_vmstate, self) < 0) {
426         error_setg(errp, "Failed to register vmstate");
427     }
428 }
429 
430 static void
431 dbus_vmstate_finalize(Object *o)
432 {
433     DBusVMState *self = DBUS_VMSTATE(o);
434 
435     vmstate_unregister(VMSTATE_IF(self), &dbus_vmstate, self);
436 
437     g_clear_object(&self->bus);
438     g_free(self->dbus_addr);
439     g_free(self->id_list);
440     g_free(self->data);
441 }
442 
443 static char *
444 get_dbus_addr(Object *o, Error **errp)
445 {
446     DBusVMState *self = DBUS_VMSTATE(o);
447 
448     return g_strdup(self->dbus_addr);
449 }
450 
451 static void
452 set_dbus_addr(Object *o, const char *str, Error **errp)
453 {
454     DBusVMState *self = DBUS_VMSTATE(o);
455 
456     g_free(self->dbus_addr);
457     self->dbus_addr = g_strdup(str);
458 }
459 
460 static char *
461 get_id_list(Object *o, Error **errp)
462 {
463     DBusVMState *self = DBUS_VMSTATE(o);
464 
465     return g_strdup(self->id_list);
466 }
467 
468 static void
469 set_id_list(Object *o, const char *str, Error **errp)
470 {
471     DBusVMState *self = DBUS_VMSTATE(o);
472 
473     g_free(self->id_list);
474     self->id_list = g_strdup(str);
475 }
476 
477 static char *
478 dbus_vmstate_get_id(VMStateIf *vmif)
479 {
480     return g_strdup(TYPE_DBUS_VMSTATE);
481 }
482 
483 static void
484 dbus_vmstate_class_init(ObjectClass *oc, void *data)
485 {
486     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
487     VMStateIfClass *vc = VMSTATE_IF_CLASS(oc);
488 
489     ucc->complete = dbus_vmstate_complete;
490     vc->get_id = dbus_vmstate_get_id;
491 
492     object_class_property_add_str(oc, "addr",
493                                   get_dbus_addr, set_dbus_addr);
494     object_class_property_add_str(oc, "id-list",
495                                   get_id_list, set_id_list);
496 }
497 
498 static const TypeInfo dbus_vmstate_info = {
499     .name = TYPE_DBUS_VMSTATE,
500     .parent = TYPE_OBJECT,
501     .instance_size = sizeof(DBusVMState),
502     .instance_finalize = dbus_vmstate_finalize,
503     .class_init = dbus_vmstate_class_init,
504     .interfaces = (InterfaceInfo[]) {
505         { TYPE_USER_CREATABLE },
506         { TYPE_VMSTATE_IF },
507         { }
508     }
509 };
510 
511 static void
512 register_types(void)
513 {
514     type_register_static(&dbus_vmstate_info);
515 }
516 
517 type_init(register_types);
518