xref: /openbmc/qemu/backends/dbus-vmstate.c (revision 835fde4a)
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);
504