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 "qemu-common.h" 15 #include "migration.h" 16 #include "migration/vmstate.h" 17 #include "savevm.h" 18 #include "qemu-file.h" 19 #include "qemu/bitops.h" 20 #include "qemu/error-report.h" 21 #include "trace.h" 22 #include "qjson.h" 23 24 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd, 25 void *opaque, QJSON *vmdesc); 26 static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, 27 void *opaque); 28 29 static int vmstate_n_elems(void *opaque, VMStateField *field) 30 { 31 int n_elems = 1; 32 33 if (field->flags & VMS_ARRAY) { 34 n_elems = field->num; 35 } else if (field->flags & VMS_VARRAY_INT32) { 36 n_elems = *(int32_t *)(opaque+field->num_offset); 37 } else if (field->flags & VMS_VARRAY_UINT32) { 38 n_elems = *(uint32_t *)(opaque+field->num_offset); 39 } else if (field->flags & VMS_VARRAY_UINT16) { 40 n_elems = *(uint16_t *)(opaque+field->num_offset); 41 } else if (field->flags & VMS_VARRAY_UINT8) { 42 n_elems = *(uint8_t *)(opaque+field->num_offset); 43 } 44 45 if (field->flags & VMS_MULTIPLY_ELEMENTS) { 46 n_elems *= field->num; 47 } 48 49 trace_vmstate_n_elems(field->name, n_elems); 50 return n_elems; 51 } 52 53 static int vmstate_size(void *opaque, VMStateField *field) 54 { 55 int size = field->size; 56 57 if (field->flags & VMS_VBUFFER) { 58 size = *(int32_t *)(opaque+field->size_offset); 59 if (field->flags & VMS_MULTIPLY) { 60 size *= field->size; 61 } 62 } 63 64 return size; 65 } 66 67 static void vmstate_handle_alloc(void *ptr, VMStateField *field, 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 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(VMStateField *start, VMStateField *search) 175 { 176 VMStateField *field; 177 int found = 0; 178 179 for (field = start; field->name; field++) { 180 if (!strcmp(field->name, search->name)) { 181 if (field == search) { 182 return found; 183 } 184 found++; 185 } 186 } 187 188 return -1; 189 } 190 191 static bool vmfield_name_is_unique(VMStateField *start, VMStateField *search) 192 { 193 VMStateField *field; 194 int found = 0; 195 196 for (field = start; field->name; field++) { 197 if (!strcmp(field->name, search->name)) { 198 found++; 199 /* name found more than once, so it's not unique */ 200 if (found > 1) { 201 return false; 202 } 203 } 204 } 205 206 return true; 207 } 208 209 static const char *vmfield_get_type_name(VMStateField *field) 210 { 211 const char *type = "unknown"; 212 213 if (field->flags & VMS_STRUCT) { 214 type = "struct"; 215 } else if (field->flags & VMS_VSTRUCT) { 216 type = "vstruct"; 217 } else if (field->info->name) { 218 type = field->info->name; 219 } 220 221 return type; 222 } 223 224 static bool vmsd_can_compress(VMStateField *field) 225 { 226 if (field->field_exists) { 227 /* Dynamically existing fields mess up compression */ 228 return false; 229 } 230 231 if (field->flags & VMS_STRUCT) { 232 VMStateField *sfield = field->vmsd->fields; 233 while (sfield->name) { 234 if (!vmsd_can_compress(sfield)) { 235 /* Child elements can't compress, so can't we */ 236 return false; 237 } 238 sfield++; 239 } 240 241 if (field->vmsd->subsections) { 242 /* Subsections may come and go, better don't compress */ 243 return false; 244 } 245 } 246 247 return true; 248 } 249 250 static void vmsd_desc_field_start(const VMStateDescription *vmsd, QJSON *vmdesc, 251 VMStateField *field, int i, int max) 252 { 253 char *name, *old_name; 254 bool is_array = max > 1; 255 bool can_compress = vmsd_can_compress(field); 256 257 if (!vmdesc) { 258 return; 259 } 260 261 name = g_strdup(field->name); 262 263 /* Field name is not unique, need to make it unique */ 264 if (!vmfield_name_is_unique(vmsd->fields, field)) { 265 int num = vmfield_name_num(vmsd->fields, field); 266 old_name = name; 267 name = g_strdup_printf("%s[%d]", name, num); 268 g_free(old_name); 269 } 270 271 json_start_object(vmdesc, NULL); 272 json_prop_str(vmdesc, "name", name); 273 if (is_array) { 274 if (can_compress) { 275 json_prop_int(vmdesc, "array_len", max); 276 } else { 277 json_prop_int(vmdesc, "index", i); 278 } 279 } 280 json_prop_str(vmdesc, "type", vmfield_get_type_name(field)); 281 282 if (field->flags & VMS_STRUCT) { 283 json_start_object(vmdesc, "struct"); 284 } 285 286 g_free(name); 287 } 288 289 static void vmsd_desc_field_end(const VMStateDescription *vmsd, QJSON *vmdesc, 290 VMStateField *field, size_t size, int i) 291 { 292 if (!vmdesc) { 293 return; 294 } 295 296 if (field->flags & VMS_STRUCT) { 297 /* We printed a struct in between, close its child object */ 298 json_end_object(vmdesc); 299 } 300 301 json_prop_int(vmdesc, "size", size); 302 json_end_object(vmdesc); 303 } 304 305 306 bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque) 307 { 308 if (vmsd->needed && !vmsd->needed(opaque)) { 309 /* optional section not needed */ 310 return false; 311 } 312 return true; 313 } 314 315 316 int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, 317 void *opaque, QJSON *vmdesc_id) 318 { 319 return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id); 320 } 321 322 int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd, 323 void *opaque, QJSON *vmdesc, int version_id) 324 { 325 int ret = 0; 326 VMStateField *field = vmsd->fields; 327 328 trace_vmstate_save_state_top(vmsd->name); 329 330 if (vmsd->pre_save) { 331 ret = vmsd->pre_save(opaque); 332 trace_vmstate_save_state_pre_save_res(vmsd->name, ret); 333 if (ret) { 334 error_report("pre-save failed: %s", vmsd->name); 335 return ret; 336 } 337 } 338 339 if (vmdesc) { 340 json_prop_str(vmdesc, "vmsd_name", vmsd->name); 341 json_prop_int(vmdesc, "version", version_id); 342 json_start_array(vmdesc, "fields"); 343 } 344 345 while (field->name) { 346 if ((field->field_exists && 347 field->field_exists(opaque, version_id)) || 348 (!field->field_exists && 349 field->version_id <= version_id)) { 350 void *first_elem = opaque + field->offset; 351 int i, n_elems = vmstate_n_elems(opaque, field); 352 int size = vmstate_size(opaque, field); 353 int64_t old_offset, written_bytes; 354 QJSON *vmdesc_loop = vmdesc; 355 356 trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems); 357 if (field->flags & VMS_POINTER) { 358 first_elem = *(void **)first_elem; 359 assert(first_elem || !n_elems || !size); 360 } 361 for (i = 0; i < n_elems; i++) { 362 void *curr_elem = first_elem + size * i; 363 ret = 0; 364 365 vmsd_desc_field_start(vmsd, vmdesc_loop, field, i, n_elems); 366 old_offset = qemu_ftell_fast(f); 367 if (field->flags & VMS_ARRAY_OF_POINTER) { 368 assert(curr_elem); 369 curr_elem = *(void **)curr_elem; 370 } 371 if (!curr_elem && size) { 372 /* if null pointer write placeholder and do not follow */ 373 assert(field->flags & VMS_ARRAY_OF_POINTER); 374 ret = vmstate_info_nullptr.put(f, curr_elem, size, NULL, 375 NULL); 376 } else if (field->flags & VMS_STRUCT) { 377 ret = vmstate_save_state(f, field->vmsd, curr_elem, 378 vmdesc_loop); 379 } else if (field->flags & VMS_VSTRUCT) { 380 ret = vmstate_save_state_v(f, field->vmsd, curr_elem, 381 vmdesc_loop, 382 field->struct_version_id); 383 } else { 384 ret = field->info->put(f, curr_elem, size, field, 385 vmdesc_loop); 386 } 387 if (ret) { 388 error_report("Save of field %s/%s failed", 389 vmsd->name, field->name); 390 return ret; 391 } 392 393 written_bytes = qemu_ftell_fast(f) - old_offset; 394 vmsd_desc_field_end(vmsd, vmdesc_loop, field, written_bytes, i); 395 396 /* Compressed arrays only care about the first element */ 397 if (vmdesc_loop && vmsd_can_compress(field)) { 398 vmdesc_loop = NULL; 399 } 400 } 401 } else { 402 if (field->flags & VMS_MUST_EXIST) { 403 error_report("Output state validation failed: %s/%s", 404 vmsd->name, field->name); 405 assert(!(field->flags & VMS_MUST_EXIST)); 406 } 407 } 408 field++; 409 } 410 411 if (vmdesc) { 412 json_end_array(vmdesc); 413 } 414 415 return vmstate_subsection_save(f, vmsd, opaque, vmdesc); 416 } 417 418 static const VMStateDescription * 419 vmstate_get_subsection(const VMStateDescription **sub, char *idstr) 420 { 421 while (sub && *sub) { 422 if (strcmp(idstr, (*sub)->name) == 0) { 423 return *sub; 424 } 425 sub++; 426 } 427 return NULL; 428 } 429 430 static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, 431 void *opaque) 432 { 433 trace_vmstate_subsection_load(vmsd->name); 434 435 while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) { 436 char idstr[256], *idstr_ret; 437 int ret; 438 uint8_t version_id, len, size; 439 const VMStateDescription *sub_vmsd; 440 441 len = qemu_peek_byte(f, 1); 442 if (len < strlen(vmsd->name) + 1) { 443 /* subsection name has be be "section_name/a" */ 444 trace_vmstate_subsection_load_bad(vmsd->name, "(short)", ""); 445 return 0; 446 } 447 size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2); 448 if (size != len) { 449 trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)", ""); 450 return 0; 451 } 452 memcpy(idstr, idstr_ret, size); 453 idstr[size] = 0; 454 455 if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) { 456 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(prefix)"); 457 /* it doesn't have a valid subsection name */ 458 return 0; 459 } 460 sub_vmsd = vmstate_get_subsection(vmsd->subsections, idstr); 461 if (sub_vmsd == NULL) { 462 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(lookup)"); 463 return -ENOENT; 464 } 465 qemu_file_skip(f, 1); /* subsection */ 466 qemu_file_skip(f, 1); /* len */ 467 qemu_file_skip(f, len); /* idstr */ 468 version_id = qemu_get_be32(f); 469 470 ret = vmstate_load_state(f, sub_vmsd, opaque, version_id); 471 if (ret) { 472 trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(child)"); 473 return ret; 474 } 475 } 476 477 trace_vmstate_subsection_load_good(vmsd->name); 478 return 0; 479 } 480 481 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd, 482 void *opaque, QJSON *vmdesc) 483 { 484 const VMStateDescription **sub = vmsd->subsections; 485 bool subsection_found = false; 486 int ret = 0; 487 488 trace_vmstate_subsection_save_top(vmsd->name); 489 while (sub && *sub) { 490 if (vmstate_save_needed(*sub, opaque)) { 491 const VMStateDescription *vmsdsub = *sub; 492 uint8_t len; 493 494 trace_vmstate_subsection_save_loop(vmsd->name, vmsdsub->name); 495 if (vmdesc) { 496 /* Only create subsection array when we have any */ 497 if (!subsection_found) { 498 json_start_array(vmdesc, "subsections"); 499 subsection_found = true; 500 } 501 502 json_start_object(vmdesc, NULL); 503 } 504 505 qemu_put_byte(f, QEMU_VM_SUBSECTION); 506 len = strlen(vmsdsub->name); 507 qemu_put_byte(f, len); 508 qemu_put_buffer(f, (uint8_t *)vmsdsub->name, len); 509 qemu_put_be32(f, vmsdsub->version_id); 510 ret = vmstate_save_state(f, vmsdsub, opaque, vmdesc); 511 if (ret) { 512 return ret; 513 } 514 515 if (vmdesc) { 516 json_end_object(vmdesc); 517 } 518 } 519 sub++; 520 } 521 522 if (vmdesc && subsection_found) { 523 json_end_array(vmdesc); 524 } 525 526 return ret; 527 } 528