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1 | /* | |
2 | * VMState interpreter | |
3 | * | |
4 | * Copyright (c) 2009-2017 Red Hat Inc | |
5 | * | |
6 | * Authors: | |
7 | * Juan Quintela <quintela@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 "migration.h" | |
15 | #include "migration/vmstate.h" | |
16 | #include "savevm.h" | |
17 | #include "qapi/error.h" | |
18 | #include "qapi/qmp/json-writer.h" | |
19 | #include "qemu-file.h" | |
20 | #include "qemu/bitops.h" | |
21 | #include "qemu/error-report.h" | |
22 | #include "trace.h" | |
23 | ||
24 | static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd, | |
25 | void *opaque, JSONWriter *vmdesc); | |
26 | static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, | |
27 | void *opaque); | |
28 | ||
29 | /* Whether this field should exist for either save or load the VM? */ | |
30 | static bool | |
31 | vmstate_field_exists(const VMStateDescription *vmsd, const VMStateField *field, | |
32 | void *opaque, int version_id) | |
33 | { | |
34 | bool result; | |
35 | ||
36 | if (field->field_exists) { | |
37 | /* If there's the function checker, that's the solo truth */ | |
38 | result = field->field_exists(opaque, version_id); | |
39 | trace_vmstate_field_exists(vmsd->name, field->name, field->version_id, | |
40 | version_id, result); | |
41 | } else { | |
42 | /* | |
43 | * Otherwise, we only save/load if field version is same or older. | |
44 | * For example, when loading from an old binary with old version, | |
45 | * we ignore new fields with newer version_ids. | |
46 | */ | |
47 | result = field->version_id <= version_id; | |
48 | } | |
49 | ||
50 | return result; | |
51 | } | |
52 | ||
53 | static int vmstate_n_elems(void *opaque, const VMStateField *field) | |
54 | { | |
55 | int n_elems = 1; | |
56 | ||
57 | if (field->flags & VMS_ARRAY) { | |
58 | n_elems = field->num; | |
59 | } else if (field->flags & VMS_VARRAY_INT32) { | |
60 | n_elems = *(int32_t *)(opaque + field->num_offset); | |
61 | } else if (field->flags & VMS_VARRAY_UINT32) { | |
62 | n_elems = *(uint32_t *)(opaque + field->num_offset); | |
63 | } else if (field->flags & VMS_VARRAY_UINT16) { | |
64 | n_elems = *(uint16_t *)(opaque + field->num_offset); | |
65 | } else if (field->flags & VMS_VARRAY_UINT8) { | |
66 | n_elems = *(uint8_t *)(opaque + field->num_offset); | |
67 | } | |
68 | ||
69 | if (field->flags & VMS_MULTIPLY_ELEMENTS) { | |
70 | n_elems *= field->num; | |
71 | } | |
72 | ||
73 | trace_vmstate_n_elems(field->name, n_elems); | |
74 | return n_elems; | |
75 | } | |
76 | ||
77 | static int vmstate_size(void *opaque, const VMStateField *field) | |
78 | { | |
79 | int size = field->size; | |
80 | ||
81 | if (field->flags & VMS_VBUFFER) { | |
82 | size = *(int32_t *)(opaque + field->size_offset); | |
83 | if (field->flags & VMS_MULTIPLY) { | |
84 | size *= field->size; | |
85 | } | |
86 | } | |
87 | ||
88 | return size; | |
89 | } | |
90 | ||
91 | static void vmstate_handle_alloc(void *ptr, const VMStateField *field, | |
92 | void *opaque) | |
93 | { | |
94 | if (field->flags & VMS_POINTER && field->flags & VMS_ALLOC) { | |
95 | gsize size = vmstate_size(opaque, field); | |
96 | size *= vmstate_n_elems(opaque, field); | |
97 | if (size) { | |
98 | *(void **)ptr = g_malloc(size); | |
99 | } | |
100 | } | |
101 | } | |
102 | ||
103 | int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, | |
104 | void *opaque, int version_id) | |
105 | { | |
106 | const VMStateField *field = vmsd->fields; | |
107 | int ret = 0; | |
108 | ||
109 | trace_vmstate_load_state(vmsd->name, version_id); | |
110 | if (version_id > vmsd->version_id) { | |
111 | error_report("%s: incoming version_id %d is too new " | |
112 | "for local version_id %d", | |
113 | vmsd->name, version_id, vmsd->version_id); | |
114 | trace_vmstate_load_state_end(vmsd->name, "too new", -EINVAL); | |
115 | return -EINVAL; | |
116 | } | |
117 | if (version_id < vmsd->minimum_version_id) { | |
118 | error_report("%s: incoming version_id %d is too old " | |
119 | "for local minimum version_id %d", | |
120 | vmsd->name, version_id, vmsd->minimum_version_id); | |
121 | trace_vmstate_load_state_end(vmsd->name, "too old", -EINVAL); | |
122 | return -EINVAL; | |
123 | } | |
124 | if (vmsd->pre_load) { | |
125 | ret = vmsd->pre_load(opaque); | |
126 | if (ret) { | |
127 | return ret; | |
128 | } | |
129 | } | |
130 | while (field->name) { | |
131 | trace_vmstate_load_state_field(vmsd->name, field->name); | |
132 | if (vmstate_field_exists(vmsd, field, opaque, version_id)) { | |
133 | void *first_elem = opaque + field->offset; | |
134 | int i, n_elems = vmstate_n_elems(opaque, field); | |
135 | int size = vmstate_size(opaque, field); | |
136 | ||
137 | vmstate_handle_alloc(first_elem, field, opaque); | |
138 | if (field->flags & VMS_POINTER) { | |
139 | first_elem = *(void **)first_elem; | |
140 | assert(first_elem || !n_elems || !size); | |
141 | } | |
142 | for (i = 0; i < n_elems; i++) { | |
143 | void *curr_elem = first_elem + size * i; | |
144 | ||
145 | if (field->flags & VMS_ARRAY_OF_POINTER) { | |
146 | curr_elem = *(void **)curr_elem; | |
147 | } | |
148 | if (!curr_elem && size) { | |
149 | /* if null pointer check placeholder and do not follow */ | |
150 | assert(field->flags & VMS_ARRAY_OF_POINTER); | |
151 | ret = vmstate_info_nullptr.get(f, curr_elem, size, NULL); | |
152 | } else if (field->flags & VMS_STRUCT) { | |
153 | ret = vmstate_load_state(f, field->vmsd, curr_elem, | |
154 | field->vmsd->version_id); | |
155 | } else if (field->flags & VMS_VSTRUCT) { | |
156 | ret = vmstate_load_state(f, field->vmsd, curr_elem, | |
157 | field->struct_version_id); | |
158 | } else { | |
159 | ret = field->info->get(f, curr_elem, size, field); | |
160 | } | |
161 | if (ret >= 0) { | |
162 | ret = qemu_file_get_error(f); | |
163 | } | |
164 | if (ret < 0) { | |
165 | qemu_file_set_error(f, ret); | |
166 | error_report("Failed to load %s:%s", vmsd->name, | |
167 | field->name); | |
168 | trace_vmstate_load_field_error(field->name, ret); | |
169 | return ret; | |
170 | } | |
171 | } | |
172 | } else if (field->flags & VMS_MUST_EXIST) { | |
173 | error_report("Input validation failed: %s/%s", | |
174 | vmsd->name, field->name); | |
175 | return -1; | |
176 | } | |
177 | field++; | |
178 | } | |
179 | assert(field->flags == VMS_END); | |
180 | ret = vmstate_subsection_load(f, vmsd, opaque); | |
181 | if (ret != 0) { | |
182 | qemu_file_set_error(f, ret); | |
183 | return ret; | |
184 | } | |
185 | if (vmsd->post_load) { | |
186 | ret = vmsd->post_load(opaque, version_id); | |
187 | } | |
188 | trace_vmstate_load_state_end(vmsd->name, "end", ret); | |
189 | return ret; | |
190 | } | |
191 | ||
192 | static int vmfield_name_num(const VMStateField *start, | |
193 | const VMStateField *search) | |
194 | { | |
195 | const VMStateField *field; | |
196 | int found = 0; | |
197 | ||
198 | for (field = start; field->name; field++) { | |
199 | if (!strcmp(field->name, search->name)) { | |
200 | if (field == search) { | |
201 | return found; | |
202 | } | |
203 | found++; | |
204 | } | |
205 | } | |
206 | ||
207 | return -1; | |
208 | } | |
209 | ||
210 | static bool vmfield_name_is_unique(const VMStateField *start, | |
211 | const VMStateField *search) | |
212 | { | |
213 | const VMStateField *field; | |
214 | int found = 0; | |
215 | ||
216 | for (field = start; field->name; field++) { | |
217 | if (!strcmp(field->name, search->name)) { | |
218 | found++; | |
219 | /* name found more than once, so it's not unique */ | |
220 | if (found > 1) { | |
221 | return false; | |
222 | } | |
223 | } | |
224 | } | |
225 | ||
226 | return true; | |
227 | } | |
228 | ||
229 | static const char *vmfield_get_type_name(const VMStateField *field) | |
230 | { | |
231 | const char *type = "unknown"; | |
232 | ||
233 | if (field->flags & VMS_STRUCT) { | |
234 | type = "struct"; | |
235 | } else if (field->flags & VMS_VSTRUCT) { | |
236 | type = "vstruct"; | |
237 | } else if (field->info->name) { | |
238 | type = field->info->name; | |
239 | } | |
240 | ||
241 | return type; | |
242 | } | |
243 | ||
244 | static bool vmsd_can_compress(const VMStateField *field) | |
245 | { | |
246 | if (field->field_exists) { | |
247 | /* Dynamically existing fields mess up compression */ | |
248 | return false; | |
249 | } | |
250 | ||
251 | if (field->flags & VMS_STRUCT) { | |
252 | const VMStateField *sfield = field->vmsd->fields; | |
253 | while (sfield->name) { | |
254 | if (!vmsd_can_compress(sfield)) { | |
255 | /* Child elements can't compress, so can't we */ | |
256 | return false; | |
257 | } | |
258 | sfield++; | |
259 | } | |
260 | ||
261 | if (field->vmsd->subsections) { | |
262 | /* Subsections may come and go, better don't compress */ | |
263 | return false; | |
264 | } | |
265 | } | |
266 | ||
267 | return true; | |
268 | } | |
269 | ||
270 | static void vmsd_desc_field_start(const VMStateDescription *vmsd, | |
271 | JSONWriter *vmdesc, | |
272 | const VMStateField *field, int i, int max) | |
273 | { | |
274 | char *name, *old_name; | |
275 | bool is_array = max > 1; | |
276 | bool can_compress = vmsd_can_compress(field); | |
277 | ||
278 | if (!vmdesc) { | |
279 | return; | |
280 | } | |
281 | ||
282 | name = g_strdup(field->name); | |
283 | ||
284 | /* Field name is not unique, need to make it unique */ | |
285 | if (!vmfield_name_is_unique(vmsd->fields, field)) { | |
286 | int num = vmfield_name_num(vmsd->fields, field); | |
287 | old_name = name; | |
288 | name = g_strdup_printf("%s[%d]", name, num); | |
289 | g_free(old_name); | |
290 | } | |
291 | ||
292 | json_writer_start_object(vmdesc, NULL); | |
293 | json_writer_str(vmdesc, "name", name); | |
294 | if (is_array) { | |
295 | if (can_compress) { | |
296 | json_writer_int64(vmdesc, "array_len", max); | |
297 | } else { | |
298 | json_writer_int64(vmdesc, "index", i); | |
299 | } | |
300 | } | |
301 | json_writer_str(vmdesc, "type", vmfield_get_type_name(field)); | |
302 | ||
303 | if (field->flags & VMS_STRUCT) { | |
304 | json_writer_start_object(vmdesc, "struct"); | |
305 | } | |
306 | ||
307 | g_free(name); | |
308 | } | |
309 | ||
310 | static void vmsd_desc_field_end(const VMStateDescription *vmsd, | |
311 | JSONWriter *vmdesc, | |
312 | const VMStateField *field, size_t size, int i) | |
313 | { | |
314 | if (!vmdesc) { | |
315 | return; | |
316 | } | |
317 | ||
318 | if (field->flags & VMS_STRUCT) { | |
319 | /* We printed a struct in between, close its child object */ | |
320 | json_writer_end_object(vmdesc); | |
321 | } | |
322 | ||
323 | json_writer_int64(vmdesc, "size", size); | |
324 | json_writer_end_object(vmdesc); | |
325 | } | |
326 | ||
327 | ||
328 | bool vmstate_section_needed(const VMStateDescription *vmsd, void *opaque) | |
329 | { | |
330 | if (vmsd->needed && !vmsd->needed(opaque)) { | |
331 | /* optional section not needed */ | |
332 | return false; | |
333 | } | |
334 | return true; | |
335 | } | |
336 | ||
337 | ||
338 | int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, | |
339 | void *opaque, JSONWriter *vmdesc_id) | |
340 | { | |
341 | return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id, NULL); | |
342 | } | |
343 | ||
344 | int vmstate_save_state_with_err(QEMUFile *f, const VMStateDescription *vmsd, | |
345 | void *opaque, JSONWriter *vmdesc_id, Error **errp) | |
346 | { | |
347 | return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id, errp); | |
348 | } | |
349 | ||
350 | int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, | |
351 | void *opaque, JSONWriter *vmdesc, int version_id, Error **errp) | |
352 | { | |
353 | int ret = 0; | |
354 | const VMStateField *field = vmsd->fields; | |
355 | ||
356 | trace_vmstate_save_state_top(vmsd->name); | |
357 | ||
358 | if (vmsd->pre_save) { | |
359 | ret = vmsd->pre_save(opaque); | |
360 | trace_vmstate_save_state_pre_save_res(vmsd->name, ret); | |
361 | if (ret) { | |
362 | error_setg(errp, "pre-save failed: %s", vmsd->name); | |
363 | return ret; | |
364 | } | |
365 | } | |
366 | ||
367 | if (vmdesc) { | |
368 | json_writer_str(vmdesc, "vmsd_name", vmsd->name); | |
369 | json_writer_int64(vmdesc, "version", version_id); | |
370 | json_writer_start_array(vmdesc, "fields"); | |
371 | } | |
372 | ||
373 | while (field->name) { | |
374 | if (vmstate_field_exists(vmsd, field, opaque, version_id)) { | |
375 | void *first_elem = opaque + field->offset; | |
376 | int i, n_elems = vmstate_n_elems(opaque, field); | |
377 | int size = vmstate_size(opaque, field); | |
378 | uint64_t old_offset, written_bytes; | |
379 | JSONWriter *vmdesc_loop = vmdesc; | |
380 | ||
381 | trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems); | |
382 | if (field->flags & VMS_POINTER) { | |
383 | first_elem = *(void **)first_elem; | |
384 | assert(first_elem || !n_elems || !size); | |
385 | } | |
386 | for (i = 0; i < n_elems; i++) { | |
387 | void *curr_elem = first_elem + size * i; | |
388 | ||
389 | vmsd_desc_field_start(vmsd, vmdesc_loop, field, i, n_elems); | |
390 | old_offset = qemu_file_transferred(f); | |
391 | if (field->flags & VMS_ARRAY_OF_POINTER) { | |
392 | assert(curr_elem); | |
393 | curr_elem = *(void **)curr_elem; | |
394 | } | |
395 | if (!curr_elem && size) { | |
396 | /* if null pointer write placeholder and do not follow */ | |
397 | assert(field->flags & VMS_ARRAY_OF_POINTER); | |
398 | ret = vmstate_info_nullptr.put(f, curr_elem, size, NULL, | |
399 | NULL); | |
400 | } else if (field->flags & VMS_STRUCT) { | |
401 | ret = vmstate_save_state(f, field->vmsd, curr_elem, | |
402 | vmdesc_loop); | |
403 | } else if (field->flags & VMS_VSTRUCT) { | |
404 | ret = vmstate_save_state_v(f, field->vmsd, curr_elem, | |
405 | vmdesc_loop, | |
406 | field->struct_version_id, errp); | |
407 | } else { | |
408 | ret = field->info->put(f, curr_elem, size, field, | |
409 | vmdesc_loop); | |
410 | } | |
411 | if (ret) { | |
412 | error_setg(errp, "Save of field %s/%s failed", | |
413 | vmsd->name, field->name); | |
414 | if (vmsd->post_save) { | |
415 | vmsd->post_save(opaque); | |
416 | } | |
417 | return ret; | |
418 | } | |
419 | ||
420 | written_bytes = qemu_file_transferred(f) - old_offset; | |
421 | vmsd_desc_field_end(vmsd, vmdesc_loop, field, written_bytes, i); | |
422 | ||
423 | /* Compressed arrays only care about the first element */ | |
424 | if (vmdesc_loop && vmsd_can_compress(field)) { | |
425 | vmdesc_loop = NULL; | |
426 | } | |
427 | } | |
428 | } else { | |
429 | if (field->flags & VMS_MUST_EXIST) { | |
430 | error_report("Output state validation failed: %s/%s", | |
431 | vmsd->name, field->name); | |
432 | assert(!(field->flags & VMS_MUST_EXIST)); | |
433 | } | |
434 | } | |
435 | field++; | |
436 | } | |
437 | assert(field->flags == VMS_END); | |
438 | ||
439 | if (vmdesc) { | |
440 | json_writer_end_array(vmdesc); | |
441 | } | |
442 | ||
443 | ret = vmstate_subsection_save(f, vmsd, opaque, vmdesc); | |
444 | ||
445 | if (vmsd->post_save) { | |
446 | int ps_ret = vmsd->post_save(opaque); | |
447 | if (!ret) { | |
448 | ret = ps_ret; | |
449 | } | |
450 | } | |
451 | return ret; | |
452 | } | |
453 | ||
454 | static const VMStateDescription * | |
455 | vmstate_get_subsection(const VMStateDescription **sub, char *idstr) | |
456 | { | |
457 | while (sub && *sub) { | |
458 | if (strcmp(idstr, (*sub)->name) == 0) { | |
459 | return *sub; | |
460 | } | |
461 | sub++; | |
462 | } | |
463 | return NULL; | |
464 | } | |
465 | ||
466 | static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, | |
467 | void *opaque) | |
468 | { | |
469 | trace_vmstate_subsection_load(vmsd->name); | |
470 | ||
471 | while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) { | |
472 | char idstr[256], *idstr_ret; | |
473 | int ret; | |
474 | uint8_t version_id, len, size; | |
475 | const VMStateDescription *sub_vmsd; | |
476 | ||
477 | len = qemu_peek_byte(f, 1); | |
478 | if (len < strlen(vmsd->name) + 1) { | |
479 | /* subsection name has be be "section_name/a" */ | |
480 | trace_vmstate_subsection_load_bad(vmsd->name, "(short)", ""); | |
481 | return 0; | |
482 | } | |
483 | size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2); | |
484 | if (size != len) { | |
485 | trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)", ""); | |
486 | return 0; | |
487 | } | |
488 | memcpy(idstr, idstr_ret, size); | |
489 | idstr[size] = 0; | |
490 | ||
491 | if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) { | |
492 | trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(prefix)"); | |
493 | /* it doesn't have a valid subsection name */ | |
494 | return 0; | |
495 | } | |
496 | sub_vmsd = vmstate_get_subsection(vmsd->subsections, idstr); | |
497 | if (sub_vmsd == NULL) { | |
498 | trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(lookup)"); | |
499 | return -ENOENT; | |
500 | } | |
501 | qemu_file_skip(f, 1); /* subsection */ | |
502 | qemu_file_skip(f, 1); /* len */ | |
503 | qemu_file_skip(f, len); /* idstr */ | |
504 | version_id = qemu_get_be32(f); | |
505 | ||
506 | ret = vmstate_load_state(f, sub_vmsd, opaque, version_id); | |
507 | if (ret) { | |
508 | trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(child)"); | |
509 | return ret; | |
510 | } | |
511 | } | |
512 | ||
513 | trace_vmstate_subsection_load_good(vmsd->name); | |
514 | return 0; | |
515 | } | |
516 | ||
517 | static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd, | |
518 | void *opaque, JSONWriter *vmdesc) | |
519 | { | |
520 | const VMStateDescription **sub = vmsd->subsections; | |
521 | bool vmdesc_has_subsections = false; | |
522 | int ret = 0; | |
523 | ||
524 | trace_vmstate_subsection_save_top(vmsd->name); | |
525 | while (sub && *sub) { | |
526 | if (vmstate_section_needed(*sub, opaque)) { | |
527 | const VMStateDescription *vmsdsub = *sub; | |
528 | uint8_t len; | |
529 | ||
530 | trace_vmstate_subsection_save_loop(vmsd->name, vmsdsub->name); | |
531 | if (vmdesc) { | |
532 | /* Only create subsection array when we have any */ | |
533 | if (!vmdesc_has_subsections) { | |
534 | json_writer_start_array(vmdesc, "subsections"); | |
535 | vmdesc_has_subsections = true; | |
536 | } | |
537 | ||
538 | json_writer_start_object(vmdesc, NULL); | |
539 | } | |
540 | ||
541 | qemu_put_byte(f, QEMU_VM_SUBSECTION); | |
542 | len = strlen(vmsdsub->name); | |
543 | qemu_put_byte(f, len); | |
544 | qemu_put_buffer(f, (uint8_t *)vmsdsub->name, len); | |
545 | qemu_put_be32(f, vmsdsub->version_id); | |
546 | ret = vmstate_save_state(f, vmsdsub, opaque, vmdesc); | |
547 | if (ret) { | |
548 | return ret; | |
549 | } | |
550 | ||
551 | if (vmdesc) { | |
552 | json_writer_end_object(vmdesc); | |
553 | } | |
554 | } | |
555 | sub++; | |
556 | } | |
557 | ||
558 | if (vmdesc_has_subsections) { | |
559 | json_writer_end_array(vmdesc); | |
560 | } | |
561 | ||
562 | return ret; | |
563 | } |