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 "qemu-file.h" 18 #include "qemu/bitops.h" 19 #include "qemu/error-report.h" 20 #include "trace.h" 21 #include "qjson.h" 22 23 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd, 24 void *opaque, QJSON *vmdesc); 25 static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, 26 void *opaque); 27 28 static int vmstate_n_elems(void *opaque, const VMStateField *field) 29 { 30 int n_elems = 1; 31 32 if (field->flags & VMS_ARRAY) { 33 n_elems = field->num; 34 } else if (field->flags & VMS_VARRAY_INT32) { 35 n_elems = *(int32_t *)(opaque + field->num_offset); 36 } else if (field->flags & VMS_VARRAY_UINT32) { 37 n_elems = *(uint32_t *)(opaque + field->num_offset); 38 } else if (field->flags & VMS_VARRAY_UINT16) { 39 n_elems = *(uint16_t *)(opaque + field->num_offset); 40 } else if (field->flags & VMS_VARRAY_UINT8) { 41 n_elems = *(uint8_t *)(opaque + field->num_offset); 42 } 43 44 if (field->flags & VMS_MULTIPLY_ELEMENTS) { 45 n_elems *= field->num; 46 } 47 48 trace_vmstate_n_elems(field->name, n_elems); 49 return n_elems; 50 } 51 52 static int vmstate_size(void *opaque, const VMStateField *field) 53 { 54 int size = field->size; 55 56 if (field->flags & VMS_VBUFFER) { 57 size = *(int32_t *)(opaque + field->size_offset); 58 if (field->flags & VMS_MULTIPLY) { 59 size *= field->size; 60 } 61 } 62 63 return size; 64 } 65 66 static void vmstate_handle_alloc(void *ptr, const VMStateField *field, 67 void *opaque) 68 { 69 if (field->flags & VMS_POINTER && field->flags & VMS_ALLOC) { 70 gsize size = vmstate_size(opaque, field); 71 size *= vmstate_n_elems(opaque, field); 72 if (size) { 73 *(void **)ptr = g_malloc(size); 74 } 75 } 76 } 77 78 int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, 79 void *opaque, int version_id) 80 { 81 const VMStateField *field = vmsd->fields; 82 int ret = 0; 83 84 trace_vmstate_load_state(vmsd->name, version_id); 85 if (version_id > vmsd->version_id) { 86 error_report("%s: incoming version_id %d is too new " 87 "for local version_id %d", 88 vmsd->name, version_id, vmsd->version_id); 89 trace_vmstate_load_state_end(vmsd->name, "too new", -EINVAL); 90 return -EINVAL; 91 } 92 if (version_id < vmsd->minimum_version_id) { 93 if (vmsd->load_state_old && 94 version_id >= vmsd->minimum_version_id_old) { 95 ret = vmsd->load_state_old(f, opaque, version_id); 96 trace_vmstate_load_state_end(vmsd->name, "old path", ret); 97 return ret; 98 } 99 error_report("%s: incoming version_id %d is too old " 100 "for local minimum version_id %d", 101 vmsd->name, version_id, vmsd->minimum_version_id); 102 trace_vmstate_load_state_end(vmsd->name, "too old", -EINVAL); 103 return -EINVAL; 104 } 105 if (vmsd->pre_load) { 106 int ret = vmsd->pre_load(opaque); 107 if (ret) { 108 return ret; 109 } 110 } 111 while (field->name) { 112 trace_vmstate_load_state_field(vmsd->name, field->name); 113 if ((field->field_exists && 114 field->field_exists(opaque, version_id)) || 115 (!field->field_exists && 116 field->version_id <= version_id)) { 117 void *first_elem = opaque + field->offset; 118 int i, n_elems = vmstate_n_elems(opaque, field); 119 int size = vmstate_size(opaque, field); 120 121 vmstate_handle_alloc(first_elem, field, opaque); 122 if (field->flags & VMS_POINTER) { 123 first_elem = *(void **)first_elem; 124 assert(first_elem || !n_elems || !size); 125 } 126 for (i = 0; i < n_elems; i++) { 127 void *curr_elem = first_elem + size * i; 128 129 if (field->flags & VMS_ARRAY_OF_POINTER) { 130 curr_elem = *(void **)curr_elem; 131 } 132 if (!curr_elem && size) { 133 /* if null pointer check placeholder and do not follow */ 134 assert(field->flags & VMS_ARRAY_OF_POINTER); 135 ret = vmstate_info_nullptr.get(f, curr_elem, size, NULL); 136 } else if (field->flags & VMS_STRUCT) { 137 ret = vmstate_load_state(f, field->vmsd, curr_elem, 138 field->vmsd->version_id); 139 } else if (field->flags & VMS_VSTRUCT) { 140 ret = vmstate_load_state(f, field->vmsd, curr_elem, 141 field->struct_version_id); 142 } else { 143 ret = field->info->get(f, curr_elem, size, field); 144 } 145 if (ret >= 0) { 146 ret = qemu_file_get_error(f); 147 } 148 if (ret < 0) { 149 qemu_file_set_error(f, ret); 150 error_report("Failed to load %s:%s", vmsd->name, 151 field->name); 152 trace_vmstate_load_field_error(field->name, ret); 153 return ret; 154 } 155 } 156 } else if (field->flags & VMS_MUST_EXIST) { 157 error_report("Input validation failed: %s/%s", 158 vmsd->name, field->name); 159 return -1; 160 } 161 field++; 162 } 163 ret = vmstate_subsection_load(f, vmsd, opaque); 164 if (ret != 0) { 165 return ret; 166 } 167 if (vmsd->post_load) { 168 ret = vmsd->post_load(opaque, version_id); 169 } 170 trace_vmstate_load_state_end(vmsd->name, "end", ret); 171 return ret; 172 } 173 174 static int vmfield_name_num(const VMStateField *start, 175 const VMStateField *search) 176 { 177 const VMStateField *field; 178 int found = 0; 179 180 for (field = start; field->name; field++) { 181 if (!strcmp(field->name, search->name)) { 182 if (field == search) { 183 return found; 184 } 185 found++; 186 } 187 } 188 189 return -1; 190 } 191 192 static bool vmfield_name_is_unique(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 found++; 201 /* name found more than once, so it's not unique */ 202 if (found > 1) { 203 return false; 204 } 205 } 206 } 207 208 return true; 209 } 210 211 static const char *vmfield_get_type_name(const VMStateField *field) 212 { 213 const char *type = "unknown"; 214 215 if (field->flags & VMS_STRUCT) { 216 type = "struct"; 217 } else if (field->flags & VMS_VSTRUCT) { 218 type = "vstruct"; 219 } else if (field->info->name) { 220 type = field->info->name; 221 } 222 223 return type; 224 } 225 226 static bool vmsd_can_compress(const VMStateField *field) 227 { 228 if (field->field_exists) { 229 /* Dynamically existing fields mess up compression */ 230 return false; 231 } 232 233 if (field->flags & VMS_STRUCT) { 234 const VMStateField *sfield = field->vmsd->fields; 235 while (sfield->name) { 236 if (!vmsd_can_compress(sfield)) { 237 /* Child elements can't compress, so can't we */ 238 return false; 239 } 240 sfield++; 241 } 242 243 if (field->vmsd->subsections) { 244 /* Subsections may come and go, better don't compress */ 245 return false; 246 } 247 } 248 249 return true; 250 } 251 252 static void vmsd_desc_field_start(const VMStateDescription *vmsd, QJSON *vmdesc, 253 const VMStateField *field, int i, int max) 254 { 255 char *name, *old_name; 256 bool is_array = max > 1; 257 bool can_compress = vmsd_can_compress(field); 258 259 if (!vmdesc) { 260 return; 261 } 262 263 name = g_strdup(field->name); 264 265 /* Field name is not unique, need to make it unique */ 266 if (!vmfield_name_is_unique(vmsd->fields, field)) { 267 int num = vmfield_name_num(vmsd->fields, field); 268 old_name = name; 269 name = g_strdup_printf("%s[%d]", name, num); 270 g_free(old_name); 271 } 272 273 json_start_object(vmdesc, NULL); 274 json_prop_str(vmdesc, "name", name); 275 if (is_array) { 276 if (can_compress) { 277 json_prop_int(vmdesc, "array_len", max); 278 } else { 279 json_prop_int(vmdesc, "index", i); 280 } 281 } 282 json_prop_str(vmdesc, "type", vmfield_get_type_name(field)); 283 284 if (field->flags & VMS_STRUCT) { 285 json_start_object(vmdesc, "struct"); 286 } 287 288 g_free(name); 289 } 290 291 static void vmsd_desc_field_end(const VMStateDescription *vmsd, QJSON *vmdesc, 292 const VMStateField *field, size_t size, int i) 293 { 294 if (!vmdesc) { 295 return; 296 } 297 298 if (field->flags & VMS_STRUCT) { 299 /* We printed a struct in between, close its child object */ 300 json_end_object(vmdesc); 301 } 302 303 json_prop_int(vmdesc, "size", size); 304 json_end_object(vmdesc); 305 } 306 307 308 bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque) 309 { 310 if (vmsd->needed && !vmsd->needed(opaque)) { 311 /* optional section not needed */ 312 return false; 313 } 314 return true; 315 } 316 317 318 int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, 319 void *opaque, QJSON *vmdesc_id) 320 { 321 return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id); 322 } 323 324 int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, 325 void *opaque, QJSON *vmdesc, int version_id) 326 { 327 int ret = 0; 328 const VMStateField *field = vmsd->fields; 329 330 trace_vmstate_save_state_top(vmsd->name); 331 332 if (vmsd->pre_save) { 333 ret = vmsd->pre_save(opaque); 334 trace_vmstate_save_state_pre_save_res(vmsd->name, ret); 335 if (ret) { 336 error_report("pre-save failed: %s", vmsd->name); 337 return ret; 338 } 339 } 340 341 if (vmdesc) { 342 json_prop_str(vmdesc, "vmsd_name", vmsd->name); 343 json_prop_int(vmdesc, "version", version_id); 344 json_start_array(vmdesc, "fields"); 345 } 346 347 while (field->name) { 348 if ((field->field_exists && 349 field->field_exists(opaque, version_id)) || 350 (!field->field_exists && 351 field->version_id <= version_id)) { 352 void *first_elem = opaque + field->offset; 353 int i, n_elems = vmstate_n_elems(opaque, field); 354 int size = vmstate_size(opaque, field); 355 int64_t old_offset, written_bytes; 356 QJSON *vmdesc_loop = vmdesc; 357 358 trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems); 359 if (field->flags & VMS_POINTER) { 360 first_elem = *(void **)first_elem; 361 assert(first_elem || !n_elems || !size); 362 } 363 for (i = 0; i < n_elems; i++) { 364 void *curr_elem = first_elem + size * i; 365 366 vmsd_desc_field_start(vmsd, vmdesc_loop, field, i, n_elems); 367 old_offset = qemu_ftell_fast(f); 368 if (field->flags & VMS_ARRAY_OF_POINTER) { 369 assert(curr_elem); 370 curr_elem = *(void **)curr_elem; 371 } 372 if (!curr_elem && size) { 373 /* if null pointer write placeholder and do not follow */ 374 assert(field->flags & VMS_ARRAY_OF_POINTER); 375 ret = vmstate_info_nullptr.put(f, curr_elem, size, NULL, 376 NULL); 377 } else if (field->flags & VMS_STRUCT) { 378 ret = vmstate_save_state(f, field->vmsd, curr_elem, 379 vmdesc_loop); 380 } else if (field->flags & VMS_VSTRUCT) { 381 ret = vmstate_save_state_v(f, field->vmsd, curr_elem, 382 vmdesc_loop, 383 field->struct_version_id); 384 } else { 385 ret = field->info->put(f, curr_elem, size, field, 386 vmdesc_loop); 387 } 388 if (ret) { 389 error_report("Save of field %s/%s failed", 390 vmsd->name, field->name); 391 if (vmsd->post_save) { 392 vmsd->post_save(opaque); 393 } 394 return ret; 395 } 396 397 written_bytes = qemu_ftell_fast(f) - old_offset; 398 vmsd_desc_field_end(vmsd, vmdesc_loop, field, written_bytes, i); 399 400 /* Compressed arrays only care about the first element */ 401 if (vmdesc_loop && vmsd_can_compress(field)) { 402 vmdesc_loop = NULL; 403 } 404 } 405 } else { 406 if (field->flags & VMS_MUST_EXIST) { 407 error_report("Output state validation failed: %s/%s", 408 vmsd->name, field->name); 409 assert(!(field->flags & VMS_MUST_EXIST)); 410 } 411 } 412 field++; 413 } 414 415 if (vmdesc) { 416 json_end_array(vmdesc); 417 } 418 419 ret = vmstate_subsection_save(f, vmsd, opaque, vmdesc); 420 421 if (vmsd->post_save) { 422 int ps_ret = vmsd->post_save(opaque); 423 if (!ret) { 424 ret = ps_ret; 425 } 426 } 427 return ret; 428 } 429 430 static const VMStateDescription * 431 vmstate_get_subsection(const VMStateDescription **sub, char *idstr) 432 { 433 while (sub && *sub) { 434 if (strcmp(idstr, (*sub)->name) == 0) { 435 return *sub; 436 } 437 sub++; 438 } 439 return NULL; 440 } 441 442 static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, 443 void *opaque) 444 { 445 trace_vmstate_subsection_load(vmsd->name); 446 447 while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) { 448 char idstr[256], *idstr_ret; 449 int ret; 450 uint8_t version_id, len, size; 451 const VMStateDescription *sub_vmsd; 452 453 len = qemu_peek_byte(f, 1); 454 if (len < strlen(vmsd->name) + 1) { 455 /* subsection name has be be "section_name/a" */ 456 trace_vmstate_subsection_load_bad(vmsd->name, "(short)", ""); 457 return 0; 458 } 459 size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2); 460 if (size != len) { 461 trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)", ""); 462 return 0; 463 } 464 memcpy(idstr, idstr_ret, size); 465 idstr[size] = 0; 466 467 if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) { 468 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(prefix)"); 469 /* it doesn't have a valid subsection name */ 470 return 0; 471 } 472 sub_vmsd = vmstate_get_subsection(vmsd->subsections, idstr); 473 if (sub_vmsd == NULL) { 474 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(lookup)"); 475 return -ENOENT; 476 } 477 qemu_file_skip(f, 1); /* subsection */ 478 qemu_file_skip(f, 1); /* len */ 479 qemu_file_skip(f, len); /* idstr */ 480 version_id = qemu_get_be32(f); 481 482 ret = vmstate_load_state(f, sub_vmsd, opaque, version_id); 483 if (ret) { 484 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(child)"); 485 return ret; 486 } 487 } 488 489 trace_vmstate_subsection_load_good(vmsd->name); 490 return 0; 491 } 492 493 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd, 494 void *opaque, QJSON *vmdesc) 495 { 496 const VMStateDescription **sub = vmsd->subsections; 497 bool vmdesc_has_subsections = false; 498 int ret = 0; 499 500 trace_vmstate_subsection_save_top(vmsd->name); 501 while (sub && *sub) { 502 if (vmstate_save_needed(*sub, opaque)) { 503 const VMStateDescription *vmsdsub = *sub; 504 uint8_t len; 505 506 trace_vmstate_subsection_save_loop(vmsd->name, vmsdsub->name); 507 if (vmdesc) { 508 /* Only create subsection array when we have any */ 509 if (!vmdesc_has_subsections) { 510 json_start_array(vmdesc, "subsections"); 511 vmdesc_has_subsections = true; 512 } 513 514 json_start_object(vmdesc, NULL); 515 } 516 517 qemu_put_byte(f, QEMU_VM_SUBSECTION); 518 len = strlen(vmsdsub->name); 519 qemu_put_byte(f, len); 520 qemu_put_buffer(f, (uint8_t *)vmsdsub->name, len); 521 qemu_put_be32(f, vmsdsub->version_id); 522 ret = vmstate_save_state(f, vmsdsub, opaque, vmdesc); 523 if (ret) { 524 return ret; 525 } 526 527 if (vmdesc) { 528 json_end_object(vmdesc); 529 } 530 } 531 sub++; 532 } 533 534 if (vmdesc_has_subsections) { 535 json_end_array(vmdesc); 536 } 537 538 return ret; 539 } 540