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GeezerVison is showing github.com — cpython/Modules/_remote_debugging/code_objects.c at main · python/cpython Expand file tree/ Copy pathcode_objects.cMore file actions 606 lines (539 loc) · 20.4 KB / Copy pathcode_objects.cFile metadata and controls606 lines (539 loc) · 20.4 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 /****************************************************************************** * Remote Debugging Module - Code Object Functions * * This file contains functions for parsing code objects and line tables * from remote process memory. ******************************************************************************/ #include "_remote_debugging.h" #define MAX_LINETABLE_SIZE (64 * 1024) /* ============================================================================ * TLBC CACHING FUNCTIONS (Py_GIL_DISABLED only) * ============================================================================ */ #ifdef Py_GIL_DISABLED void tlbc_cache_entry_destroy(void *ptr) { TLBCCacheEntry *entry = (TLBCCacheEntry *)ptr; if (entry->tlbc_array) { PyMem_RawFree(entry->tlbc_array); } PyMem_RawFree(entry); } TLBCCacheEntry * get_tlbc_cache_entry(RemoteUnwinderObject *self, uintptr_t code_addr, uint32_t current_generation) { void *key = (void *)code_addr; TLBCCacheEntry *entry = _Py_hashtable_get(self->tlbc_cache, key); if (entry && entry->generation != current_generation) { // Entry is stale, remove it from the cache and destroy it TLBCCacheEntry *old = _Py_hashtable_steal(self->tlbc_cache, key); if (old != NULL) { tlbc_cache_entry_destroy(old); } return NULL; } return entry; } int cache_tlbc_array(RemoteUnwinderObject *unwinder, uintptr_t code_addr, uintptr_t tlbc_array_addr, uint32_t generation) { uintptr_t tlbc_array_ptr; void *tlbc_array = NULL; TLBCCacheEntry *entry = NULL; // Read the TLBC array pointer if (read_ptr(unwinder, tlbc_array_addr, &tlbc_array_ptr) != 0) { set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to read TLBC array pointer"); return 0; // Read error } // Validate TLBC array pointer if (tlbc_array_ptr == 0) { PyErr_SetString(PyExc_RuntimeError, "TLBC array pointer is NULL"); return 0; // No TLBC array } // Read the TLBC array size Py_ssize_t tlbc_size; if (_Py_RemoteDebug_PagedReadRemoteMemory(&unwinder->handle, tlbc_array_ptr, sizeof(tlbc_size), &tlbc_size) != 0) { set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to read TLBC array size"); return 0; // Read error } // Validate TLBC array size if (tlbc_size <= 0) { PyErr_SetString(PyExc_RuntimeError, "Invalid TLBC array size"); return 0; // Invalid size } if (tlbc_size > MAX_TLBC_SIZE) { PyErr_SetString(PyExc_RuntimeError, "TLBC array size exceeds maximum limit"); return 0; // Invalid size } assert(tlbc_size > 0 && tlbc_size <= MAX_TLBC_SIZE); // Allocate and read the entire TLBC array size_t array_data_size = tlbc_size * sizeof(void*); tlbc_array = PyMem_RawMalloc(sizeof(Py_ssize_t) + array_data_size); if (!tlbc_array) { PyErr_NoMemory(); set_exception_cause(unwinder, PyExc_MemoryError, "Failed to allocate TLBC array"); return 0; // Memory error } if (_Py_RemoteDebug_PagedReadRemoteMemory(&unwinder->handle, tlbc_array_ptr, sizeof(Py_ssize_t) + array_data_size, tlbc_array) != 0) { PyMem_RawFree(tlbc_array); set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to read TLBC array data"); return 0; // Read error } // Create cache entry entry = PyMem_RawMalloc(sizeof(TLBCCacheEntry)); if (!entry) { PyErr_NoMemory(); PyMem_RawFree(tlbc_array); set_exception_cause(unwinder, PyExc_MemoryError, "Failed to allocate TLBC cache entry"); return 0; // Memory error } entry->tlbc_array = tlbc_array; entry->tlbc_array_size = tlbc_size; entry->generation = generation; // Store in cache void *key = (void *)code_addr; if (_Py_hashtable_set(unwinder->tlbc_cache, key, entry) < 0) { tlbc_cache_entry_destroy(entry); PyErr_NoMemory(); set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to store TLBC entry in cache"); return 0; // Cache error } return 1; // Success } #endif /* ============================================================================ * LINE TABLE PARSING FUNCTIONS * ============================================================================ */ // Inline helper for bounds-checked byte reading (no function call overhead) static inline int read_byte(const uint8_t **ptr, const uint8_t *end, uint8_t *out) { if (*ptr >= end) { return -1; } *out = *(*ptr)++; return 0; } static int scan_varint(const uint8_t **ptr, const uint8_t *end) { uint8_t read; if (read_byte(ptr, end, &read) < 0) { return -1; } unsigned int val = read & 63; unsigned int shift = 0; while (read & 64) { if (read_byte(ptr, end, &read) < 0) { return -1; } shift += 6; // Prevent infinite loop on malformed data (shift overflow) if (shift > 28) { return -1; } val |= (read & 63) << shift; } return (int)val; } static int scan_signed_varint(const uint8_t **ptr, const uint8_t *end) { int uval = scan_varint(ptr, end); if (uval < 0) { return INT_MIN; // Error sentinel (valid signed varints won't be INT_MIN) } if (uval & 1) { return -(int)((unsigned int)uval >> 1); } else { return (int)((unsigned int)uval >> 1); } } bool parse_linetable(const uintptr_t addrq, const char* linetable, Py_ssize_t linetable_size, int firstlineno, LocationInfo* info) { // Reject garbage: zero or negative size if (linetable_size <= 0) { return false; } const uint8_t* ptr = (const uint8_t*)(linetable); const uint8_t* end = ptr + linetable_size; uintptr_t addr = 0; int computed_line = firstlineno; // Running accumulator, separate from output int val; // Temporary for varint results uint8_t byte; // Temporary for byte reads while (ptr < end && *ptr != '\0') { uint8_t first_byte = *(ptr++); uint8_t code = (first_byte >> 3) & 15; size_t length = (first_byte & 7) + 1; uintptr_t end_addr = addr + length; switch (code) { case PY_CODE_LOCATION_INFO_NONE: info->lineno = info->end_lineno = -1; info->column = info->end_column = -1; break; case PY_CODE_LOCATION_INFO_LONG: val = scan_signed_varint(&ptr, end); if (val == INT_MIN) { return false; } computed_line += val; info->lineno = computed_line; val = scan_varint(&ptr, end); if (val < 0) { return false; } info->end_lineno = computed_line + val; val = scan_varint(&ptr, end); if (val < 0) { return false; } info->column = val - 1; val = scan_varint(&ptr, end); if (val < 0) { return false; } info->end_column = val - 1; break; case PY_CODE_LOCATION_INFO_NO_COLUMNS: val = scan_signed_varint(&ptr, end); if (val == INT_MIN) { return false; } computed_line += val; info->lineno = info->end_lineno = computed_line; info->column = info->end_column = -1; break; case PY_CODE_LOCATION_INFO_ONE_LINE0: case PY_CODE_LOCATION_INFO_ONE_LINE1: case PY_CODE_LOCATION_INFO_ONE_LINE2: computed_line += code - 10; info->lineno = info->end_lineno = computed_line; if (read_byte(&ptr, end, &byte) < 0) { return false; } info->column = byte; if (read_byte(&ptr, end, &byte) < 0) { return false; } info->end_column = byte; break; default: { if (read_byte(&ptr, end, &byte) < 0) { return false; } if ((byte & 128) != 0) { return false; } info->lineno = info->end_lineno = computed_line; info->column = code << 3 | (byte >> 4); info->end_column = info->column + (byte & 15); break; } } if (addr <= addrq && end_addr > addrq) { return true; } addr = end_addr; } return false; } /* ============================================================================ * CODE OBJECT AND FRAME INFO FUNCTIONS * ============================================================================ */ PyObject * make_location_info(RemoteUnwinderObject *unwinder, int lineno, int end_lineno, int col_offset, int end_col_offset) { RemoteDebuggingState *state = RemoteDebugging_GetStateFromObject((PyObject*)unwinder); PyObject *info = PyStructSequence_New(state->LocationInfo_Type); if (info == NULL) { set_exception_cause(unwinder, PyExc_MemoryError, "Failed to create LocationInfo"); return NULL; } PyObject *py_lineno = PyLong_FromLong(lineno); if (py_lineno == NULL) { Py_DECREF(info); return NULL; } PyStructSequence_SetItem(info, 0, py_lineno); // steals reference PyObject *py_end_lineno = PyLong_FromLong(end_lineno); if (py_end_lineno == NULL) { Py_DECREF(info); return NULL; } PyStructSequence_SetItem(info, 1, py_end_lineno); // steals reference PyObject *py_col_offset = PyLong_FromLong(col_offset); if (py_col_offset == NULL) { Py_DECREF(info); return NULL; } PyStructSequence_SetItem(info, 2, py_col_offset); // steals reference PyObject *py_end_col_offset = PyLong_FromLong(end_col_offset); if (py_end_col_offset == NULL) { Py_DECREF(info); return NULL; } PyStructSequence_SetItem(info, 3, py_end_col_offset); // steals reference return info; } PyObject * make_frame_info(RemoteUnwinderObject *unwinder, PyObject *file, PyObject *location, PyObject *func, PyObject *opcode) { RemoteDebuggingState *state = RemoteDebugging_GetStateFromObject((PyObject*)unwinder); PyObject *info = PyStructSequence_New(state->FrameInfo_Type); if (info == NULL) { set_exception_cause(unwinder, PyExc_MemoryError, "Failed to create FrameInfo"); return NULL; } Py_INCREF(file); Py_INCREF(location); Py_INCREF(func); Py_INCREF(opcode); PyStructSequence_SetItem(info, 0, file); PyStructSequence_SetItem(info, 1, location); PyStructSequence_SetItem(info, 2, func); PyStructSequence_SetItem(info, 3, opcode); return info; } int parse_code_object(RemoteUnwinderObject *unwinder, PyObject **result, const CodeObjectContext *ctx) { _Py_DECLARE_STR(unknown_function, "<unknown function>"); _Py_DECLARE_STR(unknown_file, "<unknown file>"); _Py_DECLARE_STR(unreadable_frame, "<unreadable frame>"); void *key = (void *)ctx->code_addr; CachedCodeMetadata *meta = NULL; PyObject *func = NULL; PyObject *file = NULL; PyObject *linetable = NULL; int code_metadata_incomplete = 0; #ifdef Py_GIL_DISABLED // In free threading builds, code object addresses might have the low bit set // as a flag, so we need to mask it off to get the real address uintptr_t real_address = ctx->code_addr & (~1); #else uintptr_t real_address = ctx->code_addr; #endif if (unwinder && unwinder->code_object_cache != NULL) { meta = _Py_hashtable_get(unwinder->code_object_cache, key); if (meta) { STATS_INC(unwinder, code_object_cache_hits); } else { STATS_INC(unwinder, code_object_cache_misses); } } if (meta == NULL) { char code_object[SIZEOF_CODE_OBJ]; if (_Py_RemoteDebug_PagedReadRemoteMemory( &unwinder->handle, real_address, SIZEOF_CODE_OBJ, code_object) < 0) { if (_Py_RemoteDebug_IsFatalReadError()) { goto error; } PyErr_Clear(); func = Py_NewRef(&_Py_STR(unreadable_frame)); file = Py_NewRef(_Py_LATIN1_CHR('~')); goto degraded; } func = read_py_str(unwinder, GET_MEMBER(uintptr_t, code_object, unwinder->debug_offsets.code_object.qualname), 1024); if (!func) { if (_Py_RemoteDebug_IsFatalReadError()) { goto error; } PyErr_Clear(); func = Py_NewRef(&_Py_STR(unknown_function)); code_metadata_incomplete = 1; } file = read_py_str(unwinder, GET_MEMBER(uintptr_t, code_object, unwinder->debug_offsets.code_object.filename), 1024); if (!file) { if (_Py_RemoteDebug_IsFatalReadError()) { goto error; } PyErr_Clear(); file = Py_NewRef(&_Py_STR(unknown_file)); code_metadata_incomplete = 1; } if (code_metadata_incomplete) { goto degraded; } linetable = read_py_bytes(unwinder, GET_MEMBER(uintptr_t, code_object, unwinder->debug_offsets.code_object.linetable), MAX_LINETABLE_SIZE); if (!linetable) { if (_Py_RemoteDebug_IsFatalReadError()) { goto error; } PyErr_Clear(); goto degraded; } meta = PyMem_RawMalloc(sizeof(CachedCodeMetadata)); if (!meta) { PyErr_NoMemory(); set_exception_cause(unwinder, PyExc_MemoryError, "Failed to allocate cached code metadata"); goto error; } meta->func_name = func; meta->file_name = file; meta->linetable = linetable; meta->last_frame_info = NULL; meta->last_addrq = -1; meta->first_lineno = GET_MEMBER(int, code_object, unwinder->debug_offsets.code_object.firstlineno); meta->addr_code_adaptive = real_address + (uintptr_t)unwinder->debug_offsets.code_object.co_code_adaptive; if (unwinder && unwinder->code_object_cache && _Py_hashtable_set(unwinder->code_object_cache, key, meta) < 0) { // Ownership of func/file/linetable was transferred to meta, // so NULL them before destroying meta to prevent double-free // in the error label's Py_XDECREF calls. func = NULL; file = NULL; linetable = NULL; cached_code_metadata_destroy(meta); PyErr_NoMemory(); set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to cache code metadata"); goto error; } // Ownership transferred to meta func = NULL; file = NULL; linetable = NULL; } uintptr_t ip = ctx->instruction_pointer; ptrdiff_t addrq; #ifdef Py_GIL_DISABLED // Handle thread-local bytecode (TLBC) in free threading builds if (ctx->tlbc_index == 0 || unwinder == NULL || unwinder->debug_offsets.code_object.co_tlbc == 0) { // No TLBC or no unwinder - use main bytecode directly addrq = (uint16_t *)ip - (uint16_t *)meta->addr_code_adaptive; goto done_tlbc; } // Try to get TLBC data from cache (we'll get generation from the caller) TLBCCacheEntry *tlbc_entry = get_tlbc_cache_entry(unwinder, real_address, unwinder->tlbc_generation); if (!tlbc_entry) { // Cache miss - try to read and cache TLBC array if (!cache_tlbc_array(unwinder, real_address, real_address + unwinder->debug_offsets.code_object.co_tlbc, unwinder->tlbc_generation)) { set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to cache TLBC array"); goto error; } tlbc_entry = get_tlbc_cache_entry(unwinder, real_address, unwinder->tlbc_generation); } if (tlbc_entry && ctx->tlbc_index >= 0) { uintptr_t *entries = (uintptr_t *)((char *)tlbc_entry->tlbc_array + sizeof(Py_ssize_t)); if (ctx->tlbc_index >= tlbc_entry->tlbc_array_size || entries[ctx->tlbc_index] == 0) { TLBCCacheEntry *old = _Py_hashtable_steal(unwinder->tlbc_cache, (void *)real_address); if (old != NULL) { tlbc_cache_entry_destroy(old); } if (!cache_tlbc_array(unwinder, real_address, real_address + unwinder->debug_offsets.code_object.co_tlbc, unwinder->tlbc_generation)) { goto error; } tlbc_entry = get_tlbc_cache_entry(unwinder, real_address, unwinder->tlbc_generation); } } // Validate tlbc_index and check TLBC cache if (tlbc_entry) { // Validate index bounds (also catches negative values since tlbc_index is signed) if (ctx->tlbc_index < 0 || ctx->tlbc_index >= tlbc_entry->tlbc_array_size) { PyErr_Format(PyExc_RuntimeError, "Invalid tlbc_index %d (array size %zd, corrupted remote memory)", ctx->tlbc_index, tlbc_entry->tlbc_array_size); set_exception_cause(unwinder, PyExc_RuntimeError, "Invalid tlbc_index (corrupted remote memory)"); goto error; } assert(tlbc_entry->tlbc_array_size > 0); // Use cached TLBC data uintptr_t *entries = (uintptr_t *)((char *)tlbc_entry->tlbc_array + sizeof(Py_ssize_t)); uintptr_t tlbc_bytecode_addr = entries[ctx->tlbc_index]; if (tlbc_bytecode_addr != 0) { // Calculate offset from TLBC bytecode addrq = (uint16_t *)ip - (uint16_t *)tlbc_bytecode_addr; goto done_tlbc; } } // Fall back to main bytecode (no tlbc_entry or tlbc_bytecode_addr was 0) addrq = (uint16_t *)ip - (uint16_t *)meta->addr_code_adaptive; done_tlbc: #else // Non-free-threaded build, always use the main bytecode addrq = (uint16_t *)ip - (uint16_t *)meta->addr_code_adaptive; #endif ; // Empty statement to avoid C23 extension warning if (!unwinder->opcodes && meta->last_frame_info != NULL && meta->last_addrq == addrq) { *result = Py_NewRef(meta->last_frame_info); return 0; } LocationInfo info = {0}; bool ok = parse_linetable(addrq, PyBytes_AS_STRING(meta->linetable), PyBytes_GET_SIZE(meta->linetable), meta->first_lineno, &info); if (!ok) { info.lineno = -1; info.end_lineno = -1; info.column = -1; info.end_column = -1; } // Create the LocationInfo structseq: (lineno, end_lineno, col_offset, end_col_offset) PyObject *location = make_location_info(unwinder, info.lineno, info.end_lineno, info.column, info.end_column); if (!location) { goto error; } // Read the instruction opcode from target process if opcodes flag is set PyObject *opcode_obj = NULL; if (unwinder->opcodes) { uint16_t instruction_word = 0; if (_Py_RemoteDebug_PagedReadRemoteMemory(&unwinder->handle, ip, sizeof(uint16_t), &instruction_word) == 0) { opcode_obj = PyLong_FromLong(instruction_word & 0xFF); if (!opcode_obj) { Py_DECREF(location); set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to create opcode object"); goto error; } } else { // Opcode read failed - clear the exception since opcode is optional PyErr_Clear(); } } PyObject *tuple = make_frame_info(unwinder, meta->file_name, location, meta->func_name, opcode_obj ? opcode_obj : Py_None); Py_DECREF(location); Py_XDECREF(opcode_obj); if (!tuple) { goto error; } if (!unwinder->opcodes) { Py_XSETREF(meta->last_frame_info, Py_NewRef(tuple)); meta->last_addrq = addrq; } *result = tuple; return 0; degraded: { PyObject *degraded_tuple = make_frame_info(unwinder, file, Py_None, func, Py_None); Py_CLEAR(func); Py_CLEAR(file); if (!degraded_tuple) { return -1; } *result = degraded_tuple; return 0; } error: Py_XDECREF(func); Py_XDECREF(file); Py_XDECREF(linetable); return -1; } |
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