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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 | /* * Copyright (c) 2021 Apple Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #include "MemoryBuffer.h" #include <algorithm> #include <mach-o/loader.h> #include <sys/types.h> #include <assert.h> #include <limits.h> #include <stdlib.h> #include <string.h> #if !TARGET_OS_EXCLAVEKIT #include <mach-o/stab.h> #endif #include "Symbol.h" #include "NListSymbolTable.h" #include "Misc.h" namespace mach_o { // // MARK: --- NListSymbolTable inspection methods --- // NListSymbolTable::NListSymbolTable(uint32_t preferredLoadAddress, const struct nlist* symbols, uint32_t nlistCount, const char* stringPool, uint32_t stringPoolSize, uint32_t localsCount, uint32_t globalsCount, uint32_t undefsCount) : _preferredLoadAddress(preferredLoadAddress), _stringPool(stringPool), _nlist32(symbols), _nlist64(nullptr), _stringPoolSize(stringPoolSize), _nlistCount(nlistCount), _localsCount(localsCount), _globalsCount(globalsCount), _undefsCount(undefsCount) { } NListSymbolTable::NListSymbolTable(uint64_t preferredLoadAddress, const struct nlist_64* symbols, uint32_t nlistCount, const char* stringPool, uint32_t stringPoolSize, uint32_t localsCount, uint32_t globalsCount, uint32_t undefsCount) : _preferredLoadAddress(preferredLoadAddress), _stringPool(stringPool), _nlist32(nullptr), _nlist64(symbols), _stringPoolSize(stringPoolSize), _nlistCount(nlistCount), _localsCount(localsCount), _globalsCount(globalsCount), _undefsCount(undefsCount) { } Error NListSymbolTable::valid(uint64_t maxVmOffset) const { // FIXME return Error::none(); } int NListSymbolTable::libOrdinalFromDesc(uint16_t n_desc) const { // -flat_namespace is always flat lookup // if ( (this->flags & MH_TWOLEVEL) == 0 ) // return BIND_SPECIAL_DYLIB_FLAT_LOOKUP; // extract byte from undefined symbol entry int libIndex = GET_LIBRARY_ORDINAL(n_desc); switch ( libIndex ) { case SELF_LIBRARY_ORDINAL: return BIND_SPECIAL_DYLIB_SELF; case DYNAMIC_LOOKUP_ORDINAL: return BIND_SPECIAL_DYLIB_FLAT_LOOKUP; case EXECUTABLE_ORDINAL: return BIND_SPECIAL_DYLIB_MAIN_EXECUTABLE; } return libIndex; } Symbol NListSymbolTable::symbolFromNList(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc) const { bool dontDeadStrip = (n_desc & N_NO_DEAD_STRIP); bool cold = (n_desc & N_COLD_FUNC); bool isThumb = (n_desc & N_ARM_THUMB_DEF); switch ( n_type & N_TYPE ) { case N_UNDF: if ( n_value == 0 ) return Symbol::makeUndefined(symbolName, libOrdinalFromDesc(n_desc), ((n_desc & N_WEAK_REF) != 0)); else if ( n_type & N_PEXT ) return Symbol::makeHiddenTentativeDef(symbolName, n_value, GET_COMM_ALIGN(n_desc), dontDeadStrip, cold); else return Symbol::makeTentativeDef(symbolName, n_value, GET_COMM_ALIGN(n_desc), dontDeadStrip, cold); case N_ABS: { Symbol::Scope scope = Symbol::Scope::global; if ( (n_type & N_EXT) == 0 ) { if ( n_type & N_PEXT ) scope = Symbol::Scope::wasLinkageUnit; else scope = Symbol::Scope::translationUnit; } else if ( n_type & N_PEXT ) scope = Symbol::Scope::linkageUnit; else scope = Symbol::Scope::global; return Symbol::makeAbsolute(symbolName, n_value, dontDeadStrip, scope); } case N_INDR: { const char* importName = symbolName; if ( n_value < _stringPoolSize ) importName = _stringPool + n_value; if ( (n_type & N_EXT) == 0 ) { if ( (n_type & N_PEXT )) return Symbol::makeReExport(symbolName, 0, importName, Symbol::Scope::wasLinkageUnit); else return Symbol::makeReExport(symbolName, 0, importName, Symbol::Scope::translationUnit); } else if ( (n_type & N_PEXT ) ) return Symbol::makeReExport(symbolName, 0, importName, Symbol::Scope::linkageUnit); else return Symbol::makeReExport(symbolName, 0, importName, Symbol::Scope::global); } case N_SECT: { if ( (n_type & N_EXT) == 0 ) { if ( n_desc & N_ALT_ENTRY ) { if ( n_type & N_PEXT ) return Symbol::makeAltEntry(symbolName, n_value - _preferredLoadAddress, n_sect, Symbol::Scope::wasLinkageUnit, dontDeadStrip, cold, (n_desc & N_WEAK_DEF) != 0); else return Symbol::makeAltEntry(symbolName, n_value - _preferredLoadAddress, n_sect, Symbol::Scope::translationUnit, dontDeadStrip, cold, (n_desc & N_WEAK_DEF) != 0); } else if ( n_type & N_PEXT ) { if ( n_desc & N_WEAK_DEF ) return Symbol::makeWeakDefWasPrivateExtern(symbolName, n_value - _preferredLoadAddress, n_sect, dontDeadStrip, cold, isThumb); else return Symbol::makeRegularWasPrivateExtern(symbolName, n_value - _preferredLoadAddress, n_sect, dontDeadStrip, cold, isThumb); } else return Symbol::makeRegularLocal(symbolName, n_value - _preferredLoadAddress, n_sect, dontDeadStrip, cold, isThumb); } else if ( n_type & N_PEXT ) { if ( n_desc & N_ALT_ENTRY ) return Symbol::makeAltEntry(symbolName, n_value - _preferredLoadAddress, n_sect, Symbol::Scope::linkageUnit, dontDeadStrip, cold, (n_desc & N_WEAK_DEF) != 0); else if ( n_desc & N_WEAK_DEF ) return Symbol::makeWeakDefHidden(symbolName, n_value - _preferredLoadAddress, n_sect, dontDeadStrip, cold, isThumb); else if ( n_desc & N_SYMBOL_RESOLVER ) // rdar://123349256 (ld-prime needs to handle internal resolvers) return Symbol::makeDynamicResolver(symbolName, n_sect, 0, n_value - _preferredLoadAddress, Symbol::Scope::linkageUnit); else return Symbol::makeRegularHidden(symbolName, n_value - _preferredLoadAddress, n_sect, dontDeadStrip, cold, isThumb); } else if ( n_desc & N_ALT_ENTRY ) { return Symbol::makeAltEntry(symbolName, n_value - _preferredLoadAddress, n_sect, Symbol::Scope::global, dontDeadStrip, cold, (n_desc & N_WEAK_DEF) != 0); } else if ( (n_desc & (N_WEAK_DEF|N_WEAK_REF)) == (N_WEAK_DEF|N_WEAK_REF) ) { return Symbol::makeWeakDefAutoHide(symbolName, n_value - _preferredLoadAddress, n_sect, dontDeadStrip, cold, isThumb); } else if ( n_desc & N_WEAK_DEF ) { return Symbol::makeWeakDefExport(symbolName, n_value - _preferredLoadAddress, n_sect, dontDeadStrip, cold, isThumb); } else if ( n_desc & N_SYMBOL_RESOLVER ) { return Symbol::makeDynamicResolver(symbolName, n_sect, 0, n_value - _preferredLoadAddress); } else { bool neverStrip = (n_desc & REFERENCED_DYNAMICALLY); return Symbol::makeRegularExport(symbolName, n_value - _preferredLoadAddress, n_sect, dontDeadStrip, cold, neverStrip, isThumb); } } } return Symbol(); } void NListSymbolTable::forEachExportedSymbol(void (^callback)(const Symbol& symbol, uint32_t symbolIndex, bool& stop)) const { if ( (_localsCount == 0) && (_globalsCount == 0) && (_undefsCount == 0) && (_nlistCount != 0) ) { // if no LC_DYSYMTAB, need to scan whole table and selectively find global symbols forEachSymbol(^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { uint8_t type = n_type & N_TYPE; if ( (n_type & N_EXT) && ((type == N_SECT) || (type == N_ABS) || (type == N_INDR)) && ((n_type & N_STAB) == 0)) callback(symbolFromNList(symbolName, n_value, n_type, n_sect, n_desc), symbolIndex, stop); }); } else { uint32_t globalsStartIndex = _localsCount; forEachSymbol(globalsStartIndex, _globalsCount, ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { uint8_t type = n_type & N_TYPE; if ( (n_type & N_EXT) && ((type == N_SECT) || (type == N_ABS) || (type == N_INDR)) && ((n_type & N_STAB) == 0)) callback(symbolFromNList(symbolName, n_value, n_type, n_sect, n_desc), symbolIndex, stop); }); } } void NListSymbolTable::forEachDefinedSymbol(void (^callback)(const Symbol& symbol, uint32_t symbolIndex, bool& stop)) const { if ( (_localsCount == 0) && (_globalsCount == 0) && (_undefsCount == 0) && (_nlistCount != 0) ) { // if no LC_DYSYMTAB, need to scan whole table and selectively find defined symbols forEachSymbol(0, _nlistCount, ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { uint8_t type = n_type & N_TYPE; if ( ((type == N_SECT) || (type == N_ABS)) && ((n_type & N_STAB) == 0) ) callback(symbolFromNList(symbolName, n_value, n_type, n_sect, n_desc), symbolIndex, stop); }); } else { forEachSymbol(0, _localsCount+_globalsCount, ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { uint8_t type = n_type & N_TYPE; if ( ((type == N_SECT) || (type == N_ABS)) && ((n_type & N_STAB) == 0) ) callback(symbolFromNList(symbolName, n_value, n_type, n_sect, n_desc), symbolIndex, stop); }); } } void NListSymbolTable::forEachSymbol(void (^callback)(const Symbol& symbol, uint32_t symbolIndex, bool& stop)) const { forEachSymbol(0, _nlistCount, ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { if ( (n_type & N_STAB) == 0 ) callback(symbolFromNList(symbolName, n_value, n_type, n_sect, n_desc), symbolIndex, stop); }); } void NListSymbolTable::forEachSymbol(void (^callback)(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop)) const { forEachSymbol(0, _nlistCount, ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { callback(symbolName, n_value, n_type, n_sect, n_desc, symbolIndex, stop); }); } bool NListSymbolTable::forEachSymbol(uint32_t startSymbolIndex, uint32_t symbolCount, void (^callback)(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop)) const { bool stop = false; for (uint32_t i = 0; (i < symbolCount) && !stop; ++i ) { if ( _nlist64 != nullptr ) { const struct nlist_64& sym = _nlist64[startSymbolIndex + i]; if ( sym.n_un.n_strx > _stringPoolSize ) continue; callback(&_stringPool[sym.n_un.n_strx], sym.n_value, sym.n_type, sym.n_sect, sym.n_desc, startSymbolIndex + i, stop); } else { const struct nlist& sym = _nlist32[startSymbolIndex + i]; if ( sym.n_un.n_strx > _stringPoolSize ) continue; callback(&_stringPool[sym.n_un.n_strx], sym.n_value, sym.n_type, sym.n_sect, sym.n_desc, startSymbolIndex + i, stop); } } return stop; } bool NListSymbolTable::symbolAtIndex(uint32_t symbolIndex, Symbol& symbol) const { if ( symbolIndex >= _nlistCount ) return false; if ( _nlist64 ) { const struct nlist_64& sym = _nlist64[symbolIndex]; if ( sym.n_un.n_strx > _stringPoolSize ) return false; symbol = symbolFromNList(&_stringPool[sym.n_un.n_strx], sym.n_value, sym.n_type, sym.n_sect, sym.n_desc); return true; } if ( _nlist32 ) { const struct nlist& sym = _nlist32[symbolIndex]; if ( sym.n_un.n_strx > _stringPoolSize ) return false; symbol = symbolFromNList(&_stringPool[sym.n_un.n_strx], sym.n_value, sym.n_type, sym.n_sect, sym.n_desc); return true; } return false; } bool NListSymbolTable::findClosestDefinedSymbol(uint64_t unslidAddr, Symbol& sym) const { __block uint64_t bestNValue = 0; __block const char* bestName = nullptr; __block uint16_t bestNDesc = 0; __block uint8_t bestNType = 0; __block uint8_t bestNSect = 0; auto nlistChecker = ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { if ( ((n_type & N_TYPE) == N_SECT) && ((n_type & N_STAB) == 0) ) { if ( (bestNValue < n_value) && (n_value <= unslidAddr) ) { bestNValue = n_value; bestNDesc = n_desc; bestNType = n_type; bestNSect = n_sect; bestName = symbolName; } } }; // first walk all global symbols, then all locals, recording closet symbol <= to target const uint32_t globalsStartIndex = _localsCount; const uint32_t localsStartIndex = 0; if ( !this->forEachSymbol(globalsStartIndex, _globalsCount, nlistChecker) ) this->forEachSymbol(localsStartIndex, _localsCount, nlistChecker); if ( bestName != nullptr ) { sym = symbolFromNList(bestName, bestNValue, bestNType, bestNSect, bestNDesc); return true; } return false; } uint32_t NListSymbolTable::undefsStartIndex() const { if ( (_localsCount == 0) && (_globalsCount == 0) && (_undefsCount == 0) && (_nlistCount != 0) ) return 0; // no LC_DYSYMTAB, any symbol can be undefined return _localsCount+_globalsCount; } void NListSymbolTable::forEachUndefinedSymbol(void (^callback)(const Symbol& symbol, uint32_t symbolIndex, bool& stop)) const { if ( (_localsCount == 0) && (_globalsCount == 0) && (_undefsCount == 0) && (_nlistCount != 0) ) { // if no LC_DYSYMTAB, need to scan whole table and selectively find undefined symbols forEachSymbol(0, _nlistCount, ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { if ( ((n_type & N_TYPE) == N_UNDF) && ((n_type & N_STAB) == 0) ) callback(symbolFromNList(symbolName, n_value, n_type, n_sect, n_desc), symbolIndex, stop); }); } else { uint32_t undefinesStartIndex = _localsCount+_globalsCount; forEachSymbol(undefinesStartIndex, _undefsCount, ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { callback(symbolFromNList(symbolName, n_value, n_type, n_sect, n_desc), symbolIndex, stop); }); } } uint64_t NListSymbolTable::nValueFromSymbolIndex(uint32_t symbolIndex) const { assert(symbolIndex < _nlistCount); if ( _nlist64 != nullptr ) return _nlist64[symbolIndex].n_value; else return _nlist32[symbolIndex].n_value; } #if !TARGET_OS_EXCLAVEKIT void NListSymbolTable::forEachDebugNote(bool freeFileInfo, void (^callback)(const DebugNote& note, bool& stop)) const { __block CString currentSrcDir = nullptr; __block CString currentSrcName = nullptr; __block CString currentObjPath = nullptr; __block uint32_t currentObjModTime = 0; __block uint32_t currentObjSubType = 0; __block CString currentOriginlibPath = nullptr; __block DebugNote currentNote; // if no LC_DYSYMTAB, need to scan whole table and selectively find stab symbols uint32_t count = _localsCount; if ( (_localsCount == 0) && (_globalsCount == 0) && (_undefsCount == 0) && (_nlistCount != 0) ) count = _nlistCount; forEachSymbol(0, count, ^(const char* symbolName, uint64_t n_value, uint8_t n_type, uint8_t n_sect, uint16_t n_desc, uint32_t symbolIndex, bool& stop) { if ( (n_type & N_STAB) == 0 ) return; switch ( n_type ) { case N_SO: if ( n_sect == 1 ) { // end of file // ld64 wrote extra "end SO" at start of debug notes, we need to skip over that if ( !currentSrcName.empty() ) { // build temp DebugNoteFileInfo just for use during the callback const DebugNoteFileInfo* fileInfo = DebugNoteFileInfo::make(currentSrcDir, currentSrcName, currentObjPath, currentObjModTime, currentObjSubType, "", currentOriginlibPath); currentNote.fileInfo = fileInfo; callback(currentNote, stop); currentNote.fileInfo = nullptr; currentSrcDir = nullptr; currentSrcName = nullptr; currentObjPath = nullptr; currentObjModTime = 0; currentObjSubType = 0; currentOriginlibPath = nullptr; if ( freeFileInfo ) free((void*)fileInfo); } } else { currentNote.items.clear(); size_t len = strlen(symbolName); if ( (len > 1) && (symbolName[len-1] == '/') ) currentSrcDir = symbolName; else currentSrcName = symbolName; } break; case N_OSO: currentObjPath = symbolName; currentObjModTime = (uint32_t)n_value; currentObjSubType = n_sect; break; case N_LIB: currentOriginlibPath = symbolName; break; case N_BNSYM: currentNote.items.push_back({n_value, 0, nullptr, N_FUN, n_sect}); break; case N_FUN: if ( n_sect != 0 ) currentNote.items.back().name = symbolName; else currentNote.items.back().size = n_value; break; case N_ENSYM: break; case N_STSYM: currentNote.items.push_back({n_value, 0, symbolName, N_STSYM, n_sect}); break; case N_GSYM: currentNote.items.push_back({0, 0, symbolName, N_GSYM, 0}); break; default: // ignore other stabs break; } }); } #endif // !TARGET_OS_EXCLAVEKIT const DebugNoteFileInfo* DebugNoteFileInfo::make(CString srcDir, CString srcName, CString objPath, uint32_t objModTime, uint8_t objSubType, CString libPath, CString originLibPath) { DebugNoteFileInfo* result = (DebugNoteFileInfo*)calloc(1, sizeof(DebugNoteFileInfo)); result->_objModTime = objModTime; result->_objSubType = objSubType; result->_srcDir = srcDir; result->_srcName = srcName; result->_objPath = objPath; result->_libPath = libPath; result->_originLibPath = originLibPath; return result; } Error DebugNoteFileInfo::valid(std::span<const uint8_t> buffer) { return Error::none(); } const DebugNoteFileInfo* DebugNoteFileInfo::copy() const { return DebugNoteFileInfo::make(_srcDir, _srcName, _objPath, _objModTime, _objSubType, _libPath, _originLibPath); } bool DebugNoteFileInfo::shouldbeUpdated(CString libPath) const { // .o -> .dylib if ( !this->hasLibInfo() && !this->hasOriginLibInfo() ) return true; if ( strcmp(libPath.c_str(), this->libPath().c_str()) != 0 ) return true; return false; } __attribute__((used)) void DebugNoteFileInfo::dump() const { fprintf(stdout, "scrDir: %s\n", srcDir().c_str()); fprintf(stdout, "scrName: %s\n", srcName().c_str()); fprintf(stdout, "objPath: %s\n", objPath().c_str()); fprintf(stdout, "objModTime: 0x%08X\n", this->objModTime()); fprintf(stdout, "objSubType: 0X%02X\n", this->objSubType()); fprintf(stdout, "libPath: %s\n", hasLibInfo() ? libPath().c_str() : "N/A"); fprintf(stdout, "origlibPath: %s\n", hasOriginLibInfo() ? originLibPath().c_str() : "N/A"); } } // namespace mach_o |