| 1 | //===- ELFObjcopy.cpp -----------------------------------------------------===// |
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | #include "llvm/ObjCopy/ELF/ELFObjcopy.h" |
| 10 | #include "ELFObject.h" |
| 11 | #include "llvm/ADT/BitmaskEnum.h" |
| 12 | #include "llvm/ADT/DenseSet.h" |
| 13 | #include "llvm/ADT/SmallVector.h" |
| 14 | #include "llvm/ADT/StringRef.h" |
| 15 | #include "llvm/ADT/Twine.h" |
| 16 | #include "llvm/BinaryFormat/ELF.h" |
| 17 | #include "llvm/MC/MCTargetOptions.h" |
| 18 | #include "llvm/ObjCopy/CommonConfig.h" |
| 19 | #include "llvm/ObjCopy/ELF/ELFConfig.h" |
| 20 | #include "llvm/Object/Binary.h" |
| 21 | #include "llvm/Object/ELFObjectFile.h" |
| 22 | #include "llvm/Object/ELFTypes.h" |
| 23 | #include "llvm/Object/Error.h" |
| 24 | #include "llvm/Option/Option.h" |
| 25 | #include "llvm/Support/Casting.h" |
| 26 | #include "llvm/Support/Compression.h" |
| 27 | #include "llvm/Support/Errc.h" |
| 28 | #include "llvm/Support/Error.h" |
| 29 | #include "llvm/Support/ErrorHandling.h" |
| 30 | #include "llvm/Support/Memory.h" |
| 31 | #include "llvm/Support/raw_ostream.h" |
| 32 | #include <algorithm> |
| 33 | #include <cassert> |
| 34 | #include <cstdlib> |
| 35 | #include <functional> |
| 36 | #include <memory> |
| 37 | #include <string> |
| 38 | #include <system_error> |
| 39 | #include <utility> |
| 40 | |
| 41 | using namespace llvm; |
| 42 | using namespace llvm::ELF; |
| 43 | using namespace llvm::objcopy; |
| 44 | using namespace llvm::objcopy::elf; |
| 45 | using namespace llvm::object; |
| 46 | |
| 47 | using SectionPred = std::function<bool(const SectionBase &Sec)>; |
| 48 | |
| 49 | static bool isDebugSection(const SectionBase &Sec) { |
| 50 | return StringRef(Sec.Name).starts_with(Prefix: ".debug" ) || Sec.Name == ".gdb_index" ; |
| 51 | } |
| 52 | |
| 53 | static bool isDWOSection(const SectionBase &Sec) { |
| 54 | return StringRef(Sec.Name).ends_with(Suffix: ".dwo" ); |
| 55 | } |
| 56 | |
| 57 | static bool onlyKeepDWOPred(const Object &Obj, const SectionBase &Sec) { |
| 58 | // We can't remove the section header string table. |
| 59 | if (&Sec == Obj.SectionNames) |
| 60 | return false; |
| 61 | // Short of keeping the string table we want to keep everything that is a DWO |
| 62 | // section and remove everything else. |
| 63 | return !isDWOSection(Sec); |
| 64 | } |
| 65 | |
| 66 | static Expected<uint64_t> getNewShfFlags(SectionFlag AllFlags, |
| 67 | uint16_t EMachine) { |
| 68 | uint64_t NewFlags = 0; |
| 69 | if (AllFlags & SectionFlag::SecAlloc) |
| 70 | NewFlags |= ELF::SHF_ALLOC; |
| 71 | if (!(AllFlags & SectionFlag::SecReadonly)) |
| 72 | NewFlags |= ELF::SHF_WRITE; |
| 73 | if (AllFlags & SectionFlag::SecCode) |
| 74 | NewFlags |= ELF::SHF_EXECINSTR; |
| 75 | if (AllFlags & SectionFlag::SecMerge) |
| 76 | NewFlags |= ELF::SHF_MERGE; |
| 77 | if (AllFlags & SectionFlag::SecStrings) |
| 78 | NewFlags |= ELF::SHF_STRINGS; |
| 79 | if (AllFlags & SectionFlag::SecExclude) |
| 80 | NewFlags |= ELF::SHF_EXCLUDE; |
| 81 | if (AllFlags & SectionFlag::SecLarge) { |
| 82 | if (EMachine != EM_X86_64) |
| 83 | return createStringError(EC: errc::invalid_argument, |
| 84 | S: "section flag SHF_X86_64_LARGE can only be used " |
| 85 | "with x86_64 architecture" ); |
| 86 | NewFlags |= ELF::SHF_X86_64_LARGE; |
| 87 | } |
| 88 | return NewFlags; |
| 89 | } |
| 90 | |
| 91 | static uint64_t getSectionFlagsPreserveMask(uint64_t OldFlags, |
| 92 | uint64_t NewFlags, |
| 93 | uint16_t EMachine) { |
| 94 | // Preserve some flags which should not be dropped when setting flags. |
| 95 | // Also, preserve anything OS/processor dependant. |
| 96 | const uint64_t PreserveMask = |
| 97 | (ELF::SHF_COMPRESSED | ELF::SHF_GROUP | ELF::SHF_LINK_ORDER | |
| 98 | ELF::SHF_MASKOS | ELF::SHF_MASKPROC | ELF::SHF_TLS | |
| 99 | ELF::SHF_INFO_LINK) & |
| 100 | ~ELF::SHF_EXCLUDE & |
| 101 | ~(EMachine == EM_X86_64 ? (uint64_t)ELF::SHF_X86_64_LARGE : 0UL); |
| 102 | return (OldFlags & PreserveMask) | (NewFlags & ~PreserveMask); |
| 103 | } |
| 104 | |
| 105 | static void setSectionType(SectionBase &Sec, uint64_t Type) { |
| 106 | // If Sec's type is changed from SHT_NOBITS due to --set-section-flags, |
| 107 | // Offset may not be aligned. Align it to max(Align, 1). |
| 108 | if (Sec.Type == ELF::SHT_NOBITS && Type != ELF::SHT_NOBITS) |
| 109 | Sec.Offset = alignTo(Value: Sec.Offset, Align: std::max(a: Sec.Align, b: uint64_t(1))); |
| 110 | Sec.Type = Type; |
| 111 | } |
| 112 | |
| 113 | static Error setSectionFlagsAndType(SectionBase &Sec, SectionFlag Flags, |
| 114 | uint16_t EMachine) { |
| 115 | Expected<uint64_t> NewFlags = getNewShfFlags(AllFlags: Flags, EMachine); |
| 116 | if (!NewFlags) |
| 117 | return NewFlags.takeError(); |
| 118 | Sec.Flags = getSectionFlagsPreserveMask(OldFlags: Sec.Flags, NewFlags: *NewFlags, EMachine); |
| 119 | |
| 120 | // In GNU objcopy, certain flags promote SHT_NOBITS to SHT_PROGBITS. This rule |
| 121 | // may promote more non-ALLOC sections than GNU objcopy, but it is fine as |
| 122 | // non-ALLOC SHT_NOBITS sections do not make much sense. |
| 123 | if (Sec.Type == SHT_NOBITS && |
| 124 | (!(Sec.Flags & ELF::SHF_ALLOC) || |
| 125 | Flags & (SectionFlag::SecContents | SectionFlag::SecLoad))) |
| 126 | setSectionType(Sec, Type: ELF::SHT_PROGBITS); |
| 127 | |
| 128 | return Error::success(); |
| 129 | } |
| 130 | |
| 131 | static ElfType getOutputElfType(const Binary &Bin) { |
| 132 | // Infer output ELF type from the input ELF object |
| 133 | if (isa<ELFObjectFile<ELF32LE>>(Val: Bin)) |
| 134 | return ELFT_ELF32LE; |
| 135 | if (isa<ELFObjectFile<ELF64LE>>(Val: Bin)) |
| 136 | return ELFT_ELF64LE; |
| 137 | if (isa<ELFObjectFile<ELF32BE>>(Val: Bin)) |
| 138 | return ELFT_ELF32BE; |
| 139 | if (isa<ELFObjectFile<ELF64BE>>(Val: Bin)) |
| 140 | return ELFT_ELF64BE; |
| 141 | llvm_unreachable("Invalid ELFType" ); |
| 142 | } |
| 143 | |
| 144 | static ElfType getOutputElfType(const MachineInfo &MI) { |
| 145 | // Infer output ELF type from the binary arch specified |
| 146 | if (MI.Is64Bit) |
| 147 | return MI.IsLittleEndian ? ELFT_ELF64LE : ELFT_ELF64BE; |
| 148 | else |
| 149 | return MI.IsLittleEndian ? ELFT_ELF32LE : ELFT_ELF32BE; |
| 150 | } |
| 151 | |
| 152 | static std::unique_ptr<Writer> createELFWriter(const CommonConfig &Config, |
| 153 | Object &Obj, raw_ostream &Out, |
| 154 | ElfType OutputElfType) { |
| 155 | // Depending on the initial ELFT and OutputFormat we need a different Writer. |
| 156 | switch (OutputElfType) { |
| 157 | case ELFT_ELF32LE: |
| 158 | return std::make_unique<ELFWriter<ELF32LE>>(args&: Obj, args&: Out, args: !Config.StripSections, |
| 159 | args: Config.OnlyKeepDebug); |
| 160 | case ELFT_ELF64LE: |
| 161 | return std::make_unique<ELFWriter<ELF64LE>>(args&: Obj, args&: Out, args: !Config.StripSections, |
| 162 | args: Config.OnlyKeepDebug); |
| 163 | case ELFT_ELF32BE: |
| 164 | return std::make_unique<ELFWriter<ELF32BE>>(args&: Obj, args&: Out, args: !Config.StripSections, |
| 165 | args: Config.OnlyKeepDebug); |
| 166 | case ELFT_ELF64BE: |
| 167 | return std::make_unique<ELFWriter<ELF64BE>>(args&: Obj, args&: Out, args: !Config.StripSections, |
| 168 | args: Config.OnlyKeepDebug); |
| 169 | } |
| 170 | llvm_unreachable("Invalid output format" ); |
| 171 | } |
| 172 | |
| 173 | static std::unique_ptr<Writer> createWriter(const CommonConfig &Config, |
| 174 | Object &Obj, raw_ostream &Out, |
| 175 | ElfType OutputElfType) { |
| 176 | switch (Config.OutputFormat) { |
| 177 | case FileFormat::Binary: |
| 178 | return std::make_unique<BinaryWriter>(args&: Obj, args&: Out, args: Config); |
| 179 | case FileFormat::IHex: |
| 180 | return std::make_unique<IHexWriter>(args&: Obj, args&: Out, args: Config.OutputFilename); |
| 181 | case FileFormat::SREC: |
| 182 | return std::make_unique<SRECWriter>(args&: Obj, args&: Out, args: Config.OutputFilename); |
| 183 | default: |
| 184 | return createELFWriter(Config, Obj, Out, OutputElfType); |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | static Error dumpSectionToFile(StringRef SecName, StringRef Filename, |
| 189 | StringRef InputFilename, Object &Obj) { |
| 190 | for (auto &Sec : Obj.sections()) { |
| 191 | if (Sec.Name == SecName) { |
| 192 | if (Sec.Type == SHT_NOBITS) |
| 193 | return createFileError(F: InputFilename, EC: object_error::parse_failed, |
| 194 | Fmt: "cannot dump section '%s': it has no contents" , |
| 195 | Vals: SecName.str().c_str()); |
| 196 | Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr = |
| 197 | FileOutputBuffer::create(FilePath: Filename, Size: Sec.OriginalData.size()); |
| 198 | if (!BufferOrErr) |
| 199 | return createFileError(F: Filename, E: BufferOrErr.takeError()); |
| 200 | std::unique_ptr<FileOutputBuffer> Buf = std::move(*BufferOrErr); |
| 201 | std::copy(first: Sec.OriginalData.begin(), last: Sec.OriginalData.end(), |
| 202 | result: Buf->getBufferStart()); |
| 203 | if (Error E = Buf->commit()) |
| 204 | return createFileError(F: Filename, E: std::move(E)); |
| 205 | return Error::success(); |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | return createFileError(F: InputFilename, EC: object_error::parse_failed, |
| 210 | Fmt: "section '%s' not found" , Vals: SecName.str().c_str()); |
| 211 | } |
| 212 | |
| 213 | Error Object::compressOrDecompressSections(const CommonConfig &Config) { |
| 214 | // Build a list of sections we are going to replace. |
| 215 | // We can't call `addSection` while iterating over sections, |
| 216 | // because it would mutate the sections array. |
| 217 | SmallVector<std::pair<SectionBase *, std::function<SectionBase *()>>, 0> |
| 218 | ToReplace; |
| 219 | for (SectionBase &Sec : sections()) { |
| 220 | std::optional<DebugCompressionType> CType; |
| 221 | for (auto &[Matcher, T] : Config.compressSections) |
| 222 | if (Matcher.matches(S: Sec.Name)) |
| 223 | CType = T; |
| 224 | // Handle --compress-debug-sections and --decompress-debug-sections, which |
| 225 | // apply to non-ALLOC debug sections. |
| 226 | if (!(Sec.Flags & SHF_ALLOC) && StringRef(Sec.Name).starts_with(Prefix: ".debug" )) { |
| 227 | if (Config.CompressionType != DebugCompressionType::None) |
| 228 | CType = Config.CompressionType; |
| 229 | else if (Config.DecompressDebugSections) |
| 230 | CType = DebugCompressionType::None; |
| 231 | } |
| 232 | if (!CType) |
| 233 | continue; |
| 234 | |
| 235 | if (Sec.ParentSegment) |
| 236 | return createStringError( |
| 237 | EC: errc::invalid_argument, |
| 238 | S: "section '" + Sec.Name + |
| 239 | "' within a segment cannot be (de)compressed" ); |
| 240 | |
| 241 | if (auto *CS = dyn_cast<CompressedSection>(Val: &Sec)) { |
| 242 | if (*CType == DebugCompressionType::None) |
| 243 | ToReplace.emplace_back( |
| 244 | Args: &Sec, Args: [=] { return &addSection<DecompressedSection>(Args&: *CS); }); |
| 245 | } else if (*CType != DebugCompressionType::None) { |
| 246 | ToReplace.emplace_back(Args: &Sec, Args: [=, S = &Sec] { |
| 247 | return &addSection<CompressedSection>( |
| 248 | Args: CompressedSection(*S, *CType, Is64Bits)); |
| 249 | }); |
| 250 | } |
| 251 | } |
| 252 | |
| 253 | DenseMap<SectionBase *, SectionBase *> FromTo; |
| 254 | for (auto [S, Func] : ToReplace) |
| 255 | FromTo[S] = Func(); |
| 256 | return replaceSections(FromTo); |
| 257 | } |
| 258 | |
| 259 | static bool isAArch64MappingSymbol(const Symbol &Sym) { |
| 260 | if (Sym.Binding != STB_LOCAL || Sym.Type != STT_NOTYPE || |
| 261 | Sym.getShndx() == SHN_UNDEF) |
| 262 | return false; |
| 263 | StringRef Name = Sym.Name; |
| 264 | if (!Name.consume_front(Prefix: "$x" ) && !Name.consume_front(Prefix: "$d" )) |
| 265 | return false; |
| 266 | return Name.empty() || Name.starts_with(Prefix: "." ); |
| 267 | } |
| 268 | |
| 269 | static bool isArmMappingSymbol(const Symbol &Sym) { |
| 270 | if (Sym.Binding != STB_LOCAL || Sym.Type != STT_NOTYPE || |
| 271 | Sym.getShndx() == SHN_UNDEF) |
| 272 | return false; |
| 273 | StringRef Name = Sym.Name; |
| 274 | if (!Name.consume_front(Prefix: "$a" ) && !Name.consume_front(Prefix: "$d" ) && |
| 275 | !Name.consume_front(Prefix: "$t" )) |
| 276 | return false; |
| 277 | return Name.empty() || Name.starts_with(Prefix: "." ); |
| 278 | } |
| 279 | |
| 280 | // Check if the symbol should be preserved because it is required by ABI. |
| 281 | static bool isRequiredByABISymbol(const Object &Obj, const Symbol &Sym) { |
| 282 | switch (Obj.Machine) { |
| 283 | case EM_AARCH64: |
| 284 | // Mapping symbols should be preserved for a relocatable object file. |
| 285 | return Obj.isRelocatable() && isAArch64MappingSymbol(Sym); |
| 286 | case EM_ARM: |
| 287 | // Mapping symbols should be preserved for a relocatable object file. |
| 288 | return Obj.isRelocatable() && isArmMappingSymbol(Sym); |
| 289 | default: |
| 290 | return false; |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | static bool isUnneededSymbol(const Symbol &Sym) { |
| 295 | return !Sym.Referenced && |
| 296 | (Sym.Binding == STB_LOCAL || Sym.getShndx() == SHN_UNDEF) && |
| 297 | Sym.Type != STT_SECTION; |
| 298 | } |
| 299 | |
| 300 | static Error updateAndRemoveSymbols(const CommonConfig &Config, |
| 301 | const ELFConfig &ELFConfig, Object &Obj) { |
| 302 | // TODO: update or remove symbols only if there is an option that affects |
| 303 | // them. |
| 304 | if (!Obj.SymbolTable) |
| 305 | return Error::success(); |
| 306 | |
| 307 | Obj.SymbolTable->updateSymbols(Callable: [&](Symbol &Sym) { |
| 308 | if (Config.SymbolsToSkip.matches(S: Sym.Name)) |
| 309 | return; |
| 310 | |
| 311 | // Common and undefined symbols don't make sense as local symbols, and can |
| 312 | // even cause crashes if we localize those, so skip them. |
| 313 | if (!Sym.isCommon() && Sym.getShndx() != SHN_UNDEF && |
| 314 | ((ELFConfig.LocalizeHidden && |
| 315 | (Sym.Visibility == STV_HIDDEN || Sym.Visibility == STV_INTERNAL)) || |
| 316 | Config.SymbolsToLocalize.matches(S: Sym.Name))) |
| 317 | Sym.Binding = STB_LOCAL; |
| 318 | |
| 319 | for (auto &[Matcher, Visibility] : ELFConfig.SymbolsToSetVisibility) |
| 320 | if (Matcher.matches(S: Sym.Name)) |
| 321 | Sym.Visibility = Visibility; |
| 322 | |
| 323 | // Note: these two globalize flags have very similar names but different |
| 324 | // meanings: |
| 325 | // |
| 326 | // --globalize-symbol: promote a symbol to global |
| 327 | // --keep-global-symbol: all symbols except for these should be made local |
| 328 | // |
| 329 | // If --globalize-symbol is specified for a given symbol, it will be |
| 330 | // global in the output file even if it is not included via |
| 331 | // --keep-global-symbol. Because of that, make sure to check |
| 332 | // --globalize-symbol second. |
| 333 | if (!Config.SymbolsToKeepGlobal.empty() && |
| 334 | !Config.SymbolsToKeepGlobal.matches(S: Sym.Name) && |
| 335 | Sym.getShndx() != SHN_UNDEF) |
| 336 | Sym.Binding = STB_LOCAL; |
| 337 | |
| 338 | if (Config.SymbolsToGlobalize.matches(S: Sym.Name) && |
| 339 | Sym.getShndx() != SHN_UNDEF) |
| 340 | Sym.Binding = STB_GLOBAL; |
| 341 | |
| 342 | // SymbolsToWeaken applies to both STB_GLOBAL and STB_GNU_UNIQUE. |
| 343 | if (Config.SymbolsToWeaken.matches(S: Sym.Name) && Sym.Binding != STB_LOCAL) |
| 344 | Sym.Binding = STB_WEAK; |
| 345 | |
| 346 | if (Config.Weaken && Sym.Binding != STB_LOCAL && |
| 347 | Sym.getShndx() != SHN_UNDEF) |
| 348 | Sym.Binding = STB_WEAK; |
| 349 | |
| 350 | const auto I = Config.SymbolsToRename.find(Key: Sym.Name); |
| 351 | if (I != Config.SymbolsToRename.end()) |
| 352 | Sym.Name = std::string(I->getValue()); |
| 353 | |
| 354 | if (!Config.SymbolsPrefixRemove.empty() && Sym.Type != STT_SECTION) |
| 355 | if (StringRef(Sym.Name).starts_with(Prefix: Config.SymbolsPrefixRemove)) |
| 356 | Sym.Name = Sym.Name.substr(pos: Config.SymbolsPrefixRemove.size()); |
| 357 | |
| 358 | if (!Config.SymbolsPrefix.empty() && Sym.Type != STT_SECTION) |
| 359 | Sym.Name = (Config.SymbolsPrefix + Sym.Name).str(); |
| 360 | }); |
| 361 | |
| 362 | // The purpose of this loop is to mark symbols referenced by sections |
| 363 | // (like GroupSection or RelocationSection). This way, we know which |
| 364 | // symbols are still 'needed' and which are not. |
| 365 | if (Config.StripUnneeded || !Config.UnneededSymbolsToRemove.empty() || |
| 366 | !Config.OnlySection.empty() || Config.DiscardMode != DiscardType::None) { |
| 367 | for (SectionBase &Sec : Obj.sections()) |
| 368 | Sec.markSymbols(); |
| 369 | } |
| 370 | |
| 371 | auto RemoveSymbolsPred = [&](const Symbol &Sym) { |
| 372 | if (Config.SymbolsToKeep.matches(S: Sym.Name) || |
| 373 | (ELFConfig.KeepFileSymbols && Sym.Type == STT_FILE)) |
| 374 | return false; |
| 375 | |
| 376 | if (Config.SymbolsToRemove.matches(S: Sym.Name)) |
| 377 | return true; |
| 378 | |
| 379 | if (Config.StripAll || Config.StripAllGNU) |
| 380 | return true; |
| 381 | |
| 382 | if (isRequiredByABISymbol(Obj, Sym)) |
| 383 | return false; |
| 384 | |
| 385 | if (Config.StripDebug && Sym.Type == STT_FILE) |
| 386 | return true; |
| 387 | |
| 388 | if ((Config.StripUnneeded || |
| 389 | Config.UnneededSymbolsToRemove.matches(S: Sym.Name)) && |
| 390 | (!Obj.isRelocatable() || isUnneededSymbol(Sym))) |
| 391 | return true; |
| 392 | |
| 393 | if (!Sym.Referenced) { |
| 394 | if ((Config.DiscardMode == DiscardType::All || |
| 395 | (Config.DiscardMode == DiscardType::Locals && |
| 396 | StringRef(Sym.Name).starts_with(Prefix: ".L" ))) && |
| 397 | Sym.Binding == STB_LOCAL && Sym.getShndx() != SHN_UNDEF && |
| 398 | Sym.Type != STT_FILE && Sym.Type != STT_SECTION) |
| 399 | return true; |
| 400 | // We want to remove undefined symbols if all references have been |
| 401 | // stripped. |
| 402 | if (!Config.OnlySection.empty() && Sym.getShndx() == SHN_UNDEF) |
| 403 | return true; |
| 404 | } |
| 405 | |
| 406 | return false; |
| 407 | }; |
| 408 | |
| 409 | return Obj.removeSymbols(ToRemove: RemoveSymbolsPred); |
| 410 | } |
| 411 | |
| 412 | static Error replaceAndRemoveSections(const CommonConfig &Config, |
| 413 | const ELFConfig &ELFConfig, Object &Obj) { |
| 414 | SectionPred RemovePred = [](const SectionBase &) { return false; }; |
| 415 | |
| 416 | // Removes: |
| 417 | if (!Config.ToRemove.empty()) { |
| 418 | RemovePred = [&Config](const SectionBase &Sec) { |
| 419 | return Config.ToRemove.matches(S: Sec.Name); |
| 420 | }; |
| 421 | } |
| 422 | |
| 423 | if (Config.StripDWO) |
| 424 | RemovePred = [RemovePred](const SectionBase &Sec) { |
| 425 | return isDWOSection(Sec) || RemovePred(Sec); |
| 426 | }; |
| 427 | |
| 428 | if (Config.ExtractDWO) |
| 429 | RemovePred = [RemovePred, &Obj](const SectionBase &Sec) { |
| 430 | return onlyKeepDWOPred(Obj, Sec) || RemovePred(Sec); |
| 431 | }; |
| 432 | |
| 433 | if (Config.StripAllGNU) |
| 434 | RemovePred = [RemovePred, &Obj](const SectionBase &Sec) { |
| 435 | if (RemovePred(Sec)) |
| 436 | return true; |
| 437 | if ((Sec.Flags & SHF_ALLOC) != 0) |
| 438 | return false; |
| 439 | if (&Sec == Obj.SectionNames) |
| 440 | return false; |
| 441 | switch (Sec.Type) { |
| 442 | case SHT_SYMTAB: |
| 443 | case SHT_REL: |
| 444 | case SHT_RELA: |
| 445 | case SHT_STRTAB: |
| 446 | return true; |
| 447 | } |
| 448 | return isDebugSection(Sec); |
| 449 | }; |
| 450 | |
| 451 | if (Config.StripSections) { |
| 452 | RemovePred = [RemovePred](const SectionBase &Sec) { |
| 453 | return RemovePred(Sec) || Sec.ParentSegment == nullptr; |
| 454 | }; |
| 455 | } |
| 456 | |
| 457 | if (Config.StripDebug || Config.StripUnneeded) { |
| 458 | RemovePred = [RemovePred](const SectionBase &Sec) { |
| 459 | return RemovePred(Sec) || isDebugSection(Sec); |
| 460 | }; |
| 461 | } |
| 462 | |
| 463 | if (Config.StripNonAlloc) |
| 464 | RemovePred = [RemovePred, &Obj](const SectionBase &Sec) { |
| 465 | if (RemovePred(Sec)) |
| 466 | return true; |
| 467 | if (&Sec == Obj.SectionNames) |
| 468 | return false; |
| 469 | return (Sec.Flags & SHF_ALLOC) == 0 && Sec.ParentSegment == nullptr; |
| 470 | }; |
| 471 | |
| 472 | if (Config.StripAll) |
| 473 | RemovePred = [RemovePred, &Obj](const SectionBase &Sec) { |
| 474 | if (RemovePred(Sec)) |
| 475 | return true; |
| 476 | if (&Sec == Obj.SectionNames) |
| 477 | return false; |
| 478 | if (StringRef(Sec.Name).starts_with(Prefix: ".gnu.warning" )) |
| 479 | return false; |
| 480 | if (StringRef(Sec.Name).starts_with(Prefix: ".gnu_debuglink" )) |
| 481 | return false; |
| 482 | // We keep the .ARM.attribute section to maintain compatibility |
| 483 | // with Debian derived distributions. This is a bug in their |
| 484 | // patchset as documented here: |
| 485 | // https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=943798 |
| 486 | if (Sec.Type == SHT_ARM_ATTRIBUTES) |
| 487 | return false; |
| 488 | if (Sec.ParentSegment != nullptr) |
| 489 | return false; |
| 490 | return (Sec.Flags & SHF_ALLOC) == 0; |
| 491 | }; |
| 492 | |
| 493 | if (Config.ExtractPartition || Config.ExtractMainPartition) { |
| 494 | RemovePred = [RemovePred](const SectionBase &Sec) { |
| 495 | if (RemovePred(Sec)) |
| 496 | return true; |
| 497 | if (Sec.Type == SHT_LLVM_PART_EHDR || Sec.Type == SHT_LLVM_PART_PHDR) |
| 498 | return true; |
| 499 | return (Sec.Flags & SHF_ALLOC) != 0 && !Sec.ParentSegment; |
| 500 | }; |
| 501 | } |
| 502 | |
| 503 | // Explicit copies: |
| 504 | if (!Config.OnlySection.empty()) { |
| 505 | RemovePred = [&Config, RemovePred, &Obj](const SectionBase &Sec) { |
| 506 | // Explicitly keep these sections regardless of previous removes. |
| 507 | if (Config.OnlySection.matches(S: Sec.Name)) |
| 508 | return false; |
| 509 | |
| 510 | // Allow all implicit removes. |
| 511 | if (RemovePred(Sec)) |
| 512 | return true; |
| 513 | |
| 514 | // Keep special sections. |
| 515 | if (Obj.SectionNames == &Sec) |
| 516 | return false; |
| 517 | if (Obj.SymbolTable == &Sec || |
| 518 | (Obj.SymbolTable && Obj.SymbolTable->getStrTab() == &Sec)) |
| 519 | return false; |
| 520 | |
| 521 | // Remove everything else. |
| 522 | return true; |
| 523 | }; |
| 524 | } |
| 525 | |
| 526 | if (!Config.KeepSection.empty()) { |
| 527 | RemovePred = [&Config, RemovePred](const SectionBase &Sec) { |
| 528 | // Explicitly keep these sections regardless of previous removes. |
| 529 | if (Config.KeepSection.matches(S: Sec.Name)) |
| 530 | return false; |
| 531 | // Otherwise defer to RemovePred. |
| 532 | return RemovePred(Sec); |
| 533 | }; |
| 534 | } |
| 535 | |
| 536 | // This has to be the last predicate assignment. |
| 537 | // If the option --keep-symbol has been specified |
| 538 | // and at least one of those symbols is present |
| 539 | // (equivalently, the updated symbol table is not empty) |
| 540 | // the symbol table and the string table should not be removed. |
| 541 | if ((!Config.SymbolsToKeep.empty() || ELFConfig.KeepFileSymbols) && |
| 542 | Obj.SymbolTable && !Obj.SymbolTable->empty()) { |
| 543 | RemovePred = [&Obj, RemovePred](const SectionBase &Sec) { |
| 544 | if (&Sec == Obj.SymbolTable || &Sec == Obj.SymbolTable->getStrTab()) |
| 545 | return false; |
| 546 | return RemovePred(Sec); |
| 547 | }; |
| 548 | } |
| 549 | |
| 550 | if (Error E = Obj.removeSections(AllowBrokenLinks: ELFConfig.AllowBrokenLinks, ToRemove: RemovePred)) |
| 551 | return E; |
| 552 | |
| 553 | if (Error E = Obj.compressOrDecompressSections(Config)) |
| 554 | return E; |
| 555 | |
| 556 | return Error::success(); |
| 557 | } |
| 558 | |
| 559 | // Add symbol to the Object symbol table with the specified properties. |
| 560 | static void addSymbol(Object &Obj, const NewSymbolInfo &SymInfo, |
| 561 | uint8_t DefaultVisibility) { |
| 562 | SectionBase *Sec = Obj.findSection(Name: SymInfo.SectionName); |
| 563 | uint64_t Value = Sec ? Sec->Addr + SymInfo.Value : SymInfo.Value; |
| 564 | |
| 565 | uint8_t Bind = ELF::STB_GLOBAL; |
| 566 | uint8_t Type = ELF::STT_NOTYPE; |
| 567 | uint8_t Visibility = DefaultVisibility; |
| 568 | |
| 569 | for (SymbolFlag FlagValue : SymInfo.Flags) |
| 570 | switch (FlagValue) { |
| 571 | case SymbolFlag::Global: |
| 572 | Bind = ELF::STB_GLOBAL; |
| 573 | break; |
| 574 | case SymbolFlag::Local: |
| 575 | Bind = ELF::STB_LOCAL; |
| 576 | break; |
| 577 | case SymbolFlag::Weak: |
| 578 | Bind = ELF::STB_WEAK; |
| 579 | break; |
| 580 | case SymbolFlag::Default: |
| 581 | Visibility = ELF::STV_DEFAULT; |
| 582 | break; |
| 583 | case SymbolFlag::Hidden: |
| 584 | Visibility = ELF::STV_HIDDEN; |
| 585 | break; |
| 586 | case SymbolFlag::Protected: |
| 587 | Visibility = ELF::STV_PROTECTED; |
| 588 | break; |
| 589 | case SymbolFlag::File: |
| 590 | Type = ELF::STT_FILE; |
| 591 | break; |
| 592 | case SymbolFlag::Section: |
| 593 | Type = ELF::STT_SECTION; |
| 594 | break; |
| 595 | case SymbolFlag::Object: |
| 596 | Type = ELF::STT_OBJECT; |
| 597 | break; |
| 598 | case SymbolFlag::Function: |
| 599 | Type = ELF::STT_FUNC; |
| 600 | break; |
| 601 | case SymbolFlag::IndirectFunction: |
| 602 | Type = ELF::STT_GNU_IFUNC; |
| 603 | break; |
| 604 | default: /* Other flag values are ignored for ELF. */ |
| 605 | break; |
| 606 | }; |
| 607 | |
| 608 | Obj.SymbolTable->addSymbol( |
| 609 | Name: SymInfo.SymbolName, Bind, Type, DefinedIn: Sec, Value, Visibility, |
| 610 | Shndx: Sec ? (uint16_t)SYMBOL_SIMPLE_INDEX : (uint16_t)SHN_ABS, SymbolSize: 0); |
| 611 | } |
| 612 | |
| 613 | namespace { |
| 614 | struct RemoveNoteDetail { |
| 615 | struct DeletedRange { |
| 616 | uint64_t OldFrom; |
| 617 | uint64_t OldTo; |
| 618 | }; |
| 619 | |
| 620 | template <class ELFT> |
| 621 | static std::vector<DeletedRange> |
| 622 | findNotesToRemove(ArrayRef<uint8_t> Data, size_t Align, |
| 623 | ArrayRef<RemoveNoteInfo> NotesToRemove); |
| 624 | static std::vector<uint8_t> updateData(ArrayRef<uint8_t> OldData, |
| 625 | ArrayRef<DeletedRange> ToRemove); |
| 626 | }; |
| 627 | } // namespace |
| 628 | |
| 629 | template <class ELFT> |
| 630 | std::vector<RemoveNoteDetail::DeletedRange> |
| 631 | RemoveNoteDetail::findNotesToRemove(ArrayRef<uint8_t> Data, size_t Align, |
| 632 | ArrayRef<RemoveNoteInfo> NotesToRemove) { |
| 633 | using Elf_Nhdr = typename ELFT::Nhdr; |
| 634 | using Elf_Note = typename ELFT::Note; |
| 635 | std::vector<DeletedRange> ToRemove; |
| 636 | uint64_t CurPos = 0; |
| 637 | while (CurPos + sizeof(Elf_Nhdr) <= Data.size()) { |
| 638 | auto Nhdr = reinterpret_cast<const Elf_Nhdr *>(Data.data() + CurPos); |
| 639 | size_t FullSize = Nhdr->getSize(Align); |
| 640 | if (CurPos + FullSize > Data.size()) |
| 641 | break; |
| 642 | Elf_Note Note(*Nhdr); |
| 643 | bool ShouldRemove = |
| 644 | llvm::any_of(NotesToRemove, [&Note](const RemoveNoteInfo &NoteInfo) { |
| 645 | return NoteInfo.TypeId == Note.getType() && |
| 646 | (NoteInfo.Name.empty() || NoteInfo.Name == Note.getName()); |
| 647 | }); |
| 648 | if (ShouldRemove) |
| 649 | ToRemove.push_back(x: {.OldFrom: CurPos, .OldTo: CurPos + FullSize}); |
| 650 | CurPos += FullSize; |
| 651 | } |
| 652 | return ToRemove; |
| 653 | } |
| 654 | |
| 655 | std::vector<uint8_t> |
| 656 | RemoveNoteDetail::updateData(ArrayRef<uint8_t> OldData, |
| 657 | ArrayRef<DeletedRange> ToRemove) { |
| 658 | std::vector<uint8_t> NewData; |
| 659 | NewData.reserve(n: OldData.size()); |
| 660 | uint64_t CurPos = 0; |
| 661 | for (const DeletedRange &RemRange : ToRemove) { |
| 662 | if (CurPos < RemRange.OldFrom) { |
| 663 | auto Slice = OldData.slice(N: CurPos, M: RemRange.OldFrom - CurPos); |
| 664 | llvm::append_range(C&: NewData, R&: Slice); |
| 665 | } |
| 666 | CurPos = RemRange.OldTo; |
| 667 | } |
| 668 | if (CurPos < OldData.size()) { |
| 669 | auto Slice = OldData.slice(N: CurPos); |
| 670 | llvm::append_range(C&: NewData, R&: Slice); |
| 671 | } |
| 672 | return NewData; |
| 673 | } |
| 674 | |
| 675 | static Error removeNotes(Object &Obj, endianness Endianness, |
| 676 | ArrayRef<RemoveNoteInfo> NotesToRemove, |
| 677 | function_ref<Error(Error)> ErrorCallback) { |
| 678 | // TODO: Support note segments. |
| 679 | if (ErrorCallback) { |
| 680 | for (Segment &Seg : Obj.segments()) { |
| 681 | if (Seg.Type == PT_NOTE) { |
| 682 | if (Error E = ErrorCallback(createStringError( |
| 683 | EC: errc::not_supported, S: "note segments are not supported" ))) |
| 684 | return E; |
| 685 | break; |
| 686 | } |
| 687 | } |
| 688 | } |
| 689 | for (auto &Sec : Obj.sections()) { |
| 690 | if (Sec.Type != SHT_NOTE || !Sec.hasContents()) |
| 691 | continue; |
| 692 | // TODO: Support note sections in segments. |
| 693 | if (Sec.ParentSegment) { |
| 694 | if (ErrorCallback) |
| 695 | if (Error E = ErrorCallback(createStringError( |
| 696 | EC: errc::not_supported, |
| 697 | S: "cannot remove note(s) from " + Sec.Name + |
| 698 | ": sections in segments are not supported" ))) |
| 699 | return E; |
| 700 | continue; |
| 701 | } |
| 702 | ArrayRef<uint8_t> OldData = Sec.getContents(); |
| 703 | size_t Align = std::max<size_t>(a: 4, b: Sec.Align); |
| 704 | // Note: notes for both 32-bit and 64-bit ELF files use 4-byte words in the |
| 705 | // header, so the parsers are the same. |
| 706 | auto ToRemove = (Endianness == endianness::little) |
| 707 | ? RemoveNoteDetail::findNotesToRemove<ELF64LE>( |
| 708 | Data: OldData, Align, NotesToRemove) |
| 709 | : RemoveNoteDetail::findNotesToRemove<ELF64BE>( |
| 710 | Data: OldData, Align, NotesToRemove); |
| 711 | if (!ToRemove.empty()) { |
| 712 | if (Error E = Obj.updateSectionData( |
| 713 | S&: Sec, Data: RemoveNoteDetail::updateData(OldData, ToRemove))) |
| 714 | return E; |
| 715 | } |
| 716 | } |
| 717 | return Error::success(); |
| 718 | } |
| 719 | |
| 720 | static Error |
| 721 | handleUserSection(const NewSectionInfo &NewSection, |
| 722 | function_ref<Error(StringRef, ArrayRef<uint8_t>)> F) { |
| 723 | ArrayRef<uint8_t> Data(reinterpret_cast<const uint8_t *>( |
| 724 | NewSection.SectionData->getBufferStart()), |
| 725 | NewSection.SectionData->getBufferSize()); |
| 726 | return F(NewSection.SectionName, Data); |
| 727 | } |
| 728 | |
| 729 | static Error verifyNoteSection(StringRef Name, endianness Endianness, |
| 730 | ArrayRef<uint8_t> Data) { |
| 731 | // An ELF note has the following structure: |
| 732 | // Name Size: 4 bytes (integer) |
| 733 | // Desc Size: 4 bytes (integer) |
| 734 | // Type : 4 bytes |
| 735 | // Name : variable size, padded to a 4 byte boundary |
| 736 | // Desc : variable size, padded to a 4 byte boundary |
| 737 | |
| 738 | if (Data.empty()) |
| 739 | return Error::success(); |
| 740 | |
| 741 | if (Data.size() < 12) { |
| 742 | std::string msg; |
| 743 | raw_string_ostream(msg) |
| 744 | << Name << " data must be either empty or at least 12 bytes long" ; |
| 745 | return createStringError(EC: errc::invalid_argument, S: msg); |
| 746 | } |
| 747 | if (Data.size() % 4 != 0) { |
| 748 | std::string msg; |
| 749 | raw_string_ostream(msg) |
| 750 | << Name << " data size must be a multiple of 4 bytes" ; |
| 751 | return createStringError(EC: errc::invalid_argument, S: msg); |
| 752 | } |
| 753 | ArrayRef<uint8_t> NameSize = Data.slice(N: 0, M: 4); |
| 754 | ArrayRef<uint8_t> DescSize = Data.slice(N: 4, M: 4); |
| 755 | |
| 756 | uint32_t NameSizeValue = support::endian::read32(P: NameSize.data(), E: Endianness); |
| 757 | uint32_t DescSizeValue = support::endian::read32(P: DescSize.data(), E: Endianness); |
| 758 | |
| 759 | uint64_t ExpectedDataSize = |
| 760 | /*NameSize=*/4 + /*DescSize=*/4 + /*Type=*/4 + |
| 761 | /*Name=*/alignTo(Value: NameSizeValue, Align: 4) + |
| 762 | /*Desc=*/alignTo(Value: DescSizeValue, Align: 4); |
| 763 | uint64_t ActualDataSize = Data.size(); |
| 764 | if (ActualDataSize != ExpectedDataSize) { |
| 765 | std::string msg; |
| 766 | raw_string_ostream(msg) |
| 767 | << Name |
| 768 | << " data size is incompatible with the content of " |
| 769 | "the name and description size fields:" |
| 770 | << " expecting " << ExpectedDataSize << ", found " << ActualDataSize; |
| 771 | return createStringError(EC: errc::invalid_argument, S: msg); |
| 772 | } |
| 773 | |
| 774 | return Error::success(); |
| 775 | } |
| 776 | |
| 777 | // This function handles the high level operations of GNU objcopy including |
| 778 | // handling command line options. It's important to outline certain properties |
| 779 | // we expect to hold of the command line operations. Any operation that "keeps" |
| 780 | // should keep regardless of a remove. Additionally any removal should respect |
| 781 | // any previous removals. Lastly whether or not something is removed shouldn't |
| 782 | // depend a) on the order the options occur in or b) on some opaque priority |
| 783 | // system. The only priority is that keeps/copies overrule removes. |
| 784 | static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig, |
| 785 | ElfType OutputElfType, Object &Obj) { |
| 786 | if (Config.OutputArch) { |
| 787 | Obj.Machine = Config.OutputArch->EMachine; |
| 788 | Obj.OSABI = Config.OutputArch->OSABI; |
| 789 | } |
| 790 | |
| 791 | if (!Config.SplitDWO.empty() && Config.ExtractDWO) { |
| 792 | return Obj.removeSections( |
| 793 | AllowBrokenLinks: ELFConfig.AllowBrokenLinks, |
| 794 | ToRemove: [&Obj](const SectionBase &Sec) { return onlyKeepDWOPred(Obj, Sec); }); |
| 795 | } |
| 796 | |
| 797 | // Dump sections before add/remove for compatibility with GNU objcopy. |
| 798 | for (StringRef Flag : Config.DumpSection) { |
| 799 | StringRef SectionName; |
| 800 | StringRef FileName; |
| 801 | std::tie(args&: SectionName, args&: FileName) = Flag.split(Separator: '='); |
| 802 | if (Error E = |
| 803 | dumpSectionToFile(SecName: SectionName, Filename: FileName, InputFilename: Config.InputFilename, Obj)) |
| 804 | return E; |
| 805 | } |
| 806 | |
| 807 | // It is important to remove the sections first. For example, we want to |
| 808 | // remove the relocation sections before removing the symbols. That allows |
| 809 | // us to avoid reporting the inappropriate errors about removing symbols |
| 810 | // named in relocations. |
| 811 | if (Error E = replaceAndRemoveSections(Config, ELFConfig, Obj)) |
| 812 | return createFileError(F: Config.InputFilename, E: std::move(E)); |
| 813 | |
| 814 | if (Error E = updateAndRemoveSymbols(Config, ELFConfig, Obj)) |
| 815 | return createFileError(F: Config.InputFilename, E: std::move(E)); |
| 816 | |
| 817 | if (!Config.SetSectionAlignment.empty()) { |
| 818 | for (SectionBase &Sec : Obj.sections()) { |
| 819 | auto I = Config.SetSectionAlignment.find(Key: Sec.Name); |
| 820 | if (I != Config.SetSectionAlignment.end()) |
| 821 | Sec.Align = I->second; |
| 822 | } |
| 823 | } |
| 824 | |
| 825 | if (Config.ChangeSectionLMAValAll != 0) { |
| 826 | for (Segment &Seg : Obj.segments()) { |
| 827 | if (Seg.MemSize > 0) { |
| 828 | if (Config.ChangeSectionLMAValAll > 0 && |
| 829 | Seg.PAddr > std::numeric_limits<uint64_t>::max() - |
| 830 | Config.ChangeSectionLMAValAll) { |
| 831 | return createFileError( |
| 832 | F: Config.InputFilename, EC: errc::invalid_argument, |
| 833 | S: "address 0x" + Twine::utohexstr(Val: Seg.PAddr) + |
| 834 | " cannot be increased by 0x" + |
| 835 | Twine::utohexstr(Val: Config.ChangeSectionLMAValAll) + |
| 836 | ". The result would overflow" ); |
| 837 | } else if (Config.ChangeSectionLMAValAll < 0 && |
| 838 | Seg.PAddr < std::numeric_limits<uint64_t>::min() - |
| 839 | Config.ChangeSectionLMAValAll) { |
| 840 | return createFileError( |
| 841 | F: Config.InputFilename, EC: errc::invalid_argument, |
| 842 | S: "address 0x" + Twine::utohexstr(Val: Seg.PAddr) + |
| 843 | " cannot be decreased by 0x" + |
| 844 | Twine::utohexstr(Val: std::abs(i: Config.ChangeSectionLMAValAll)) + |
| 845 | ". The result would underflow" ); |
| 846 | } |
| 847 | Seg.PAddr += Config.ChangeSectionLMAValAll; |
| 848 | } |
| 849 | } |
| 850 | } |
| 851 | |
| 852 | if (!Config.ChangeSectionAddress.empty()) { |
| 853 | if (Obj.Type != ELF::ET_REL) |
| 854 | return createFileError( |
| 855 | F: Config.InputFilename, EC: object_error::invalid_file_type, |
| 856 | Fmt: "cannot change section address in a non-relocatable file" ); |
| 857 | StringMap<AddressUpdate> SectionsToUpdateAddress; |
| 858 | for (const SectionPatternAddressUpdate &PatternUpdate : |
| 859 | reverse(C: Config.ChangeSectionAddress)) { |
| 860 | for (SectionBase &Sec : Obj.sections()) { |
| 861 | if (PatternUpdate.SectionPattern.matches(S: Sec.Name) && |
| 862 | SectionsToUpdateAddress.try_emplace(Key: Sec.Name, Args: PatternUpdate.Update) |
| 863 | .second) { |
| 864 | if (PatternUpdate.Update.Kind == AdjustKind::Subtract && |
| 865 | Sec.Addr < PatternUpdate.Update.Value) { |
| 866 | return createFileError( |
| 867 | F: Config.InputFilename, EC: errc::invalid_argument, |
| 868 | S: "address 0x" + Twine::utohexstr(Val: Sec.Addr) + |
| 869 | " cannot be decreased by 0x" + |
| 870 | Twine::utohexstr(Val: PatternUpdate.Update.Value) + |
| 871 | ". The result would underflow" ); |
| 872 | } |
| 873 | if (PatternUpdate.Update.Kind == AdjustKind::Add && |
| 874 | Sec.Addr > std::numeric_limits<uint64_t>::max() - |
| 875 | PatternUpdate.Update.Value) { |
| 876 | return createFileError( |
| 877 | F: Config.InputFilename, EC: errc::invalid_argument, |
| 878 | S: "address 0x" + Twine::utohexstr(Val: Sec.Addr) + |
| 879 | " cannot be increased by 0x" + |
| 880 | Twine::utohexstr(Val: PatternUpdate.Update.Value) + |
| 881 | ". The result would overflow" ); |
| 882 | } |
| 883 | |
| 884 | switch (PatternUpdate.Update.Kind) { |
| 885 | case (AdjustKind::Set): |
| 886 | Sec.Addr = PatternUpdate.Update.Value; |
| 887 | break; |
| 888 | case (AdjustKind::Subtract): |
| 889 | Sec.Addr -= PatternUpdate.Update.Value; |
| 890 | break; |
| 891 | case (AdjustKind::Add): |
| 892 | Sec.Addr += PatternUpdate.Update.Value; |
| 893 | break; |
| 894 | } |
| 895 | } |
| 896 | } |
| 897 | } |
| 898 | } |
| 899 | |
| 900 | if (Config.OnlyKeepDebug) |
| 901 | for (auto &Sec : Obj.sections()) |
| 902 | if (Sec.Flags & SHF_ALLOC && Sec.Type != SHT_NOTE) |
| 903 | Sec.Type = SHT_NOBITS; |
| 904 | |
| 905 | endianness E = OutputElfType == ELFT_ELF32LE || OutputElfType == ELFT_ELF64LE |
| 906 | ? endianness::little |
| 907 | : endianness::big; |
| 908 | |
| 909 | if (!ELFConfig.NotesToRemove.empty()) { |
| 910 | if (Error Err = |
| 911 | removeNotes(Obj, Endianness: E, NotesToRemove: ELFConfig.NotesToRemove, ErrorCallback: Config.ErrorCallback)) |
| 912 | return createFileError(F: Config.InputFilename, E: std::move(Err)); |
| 913 | } |
| 914 | |
| 915 | for (const NewSectionInfo &AddedSection : Config.AddSection) { |
| 916 | auto AddSection = [&](StringRef Name, ArrayRef<uint8_t> Data) -> Error { |
| 917 | OwnedDataSection &NewSection = |
| 918 | Obj.addSection<OwnedDataSection>(Args&: Name, Args&: Data); |
| 919 | if (Name.starts_with(Prefix: ".note" ) && Name != ".note.GNU-stack" ) { |
| 920 | NewSection.Type = SHT_NOTE; |
| 921 | if (ELFConfig.VerifyNoteSections) |
| 922 | return verifyNoteSection(Name, Endianness: E, Data); |
| 923 | } |
| 924 | return Error::success(); |
| 925 | }; |
| 926 | if (Error E = handleUserSection(NewSection: AddedSection, F: AddSection)) |
| 927 | return createFileError(F: Config.InputFilename, E: std::move(E)); |
| 928 | } |
| 929 | |
| 930 | for (const NewSectionInfo &NewSection : Config.UpdateSection) { |
| 931 | auto UpdateSection = [&](StringRef Name, ArrayRef<uint8_t> Data) { |
| 932 | return Obj.updateSection(Name, Data); |
| 933 | }; |
| 934 | if (Error E = handleUserSection(NewSection, F: UpdateSection)) |
| 935 | return createFileError(F: Config.InputFilename, E: std::move(E)); |
| 936 | } |
| 937 | |
| 938 | if (!Config.AddGnuDebugLink.empty()) |
| 939 | Obj.addSection<GnuDebugLinkSection>(Args: Config.AddGnuDebugLink, |
| 940 | Args: Config.GnuDebugLinkCRC32); |
| 941 | |
| 942 | // If the symbol table was previously removed, we need to create a new one |
| 943 | // before adding new symbols. |
| 944 | if (!Obj.SymbolTable && !Config.SymbolsToAdd.empty()) |
| 945 | if (Error E = Obj.addNewSymbolTable()) |
| 946 | return createFileError(F: Config.InputFilename, E: std::move(E)); |
| 947 | |
| 948 | for (const NewSymbolInfo &SI : Config.SymbolsToAdd) |
| 949 | addSymbol(Obj, SymInfo: SI, DefaultVisibility: ELFConfig.NewSymbolVisibility); |
| 950 | |
| 951 | // --set-section-{flags,type} work with sections added by --add-section. |
| 952 | if (!Config.SetSectionFlags.empty() || !Config.SetSectionType.empty()) { |
| 953 | for (auto &Sec : Obj.sections()) { |
| 954 | const auto Iter = Config.SetSectionFlags.find(Key: Sec.Name); |
| 955 | if (Iter != Config.SetSectionFlags.end()) { |
| 956 | const SectionFlagsUpdate &SFU = Iter->second; |
| 957 | if (Error E = setSectionFlagsAndType(Sec, Flags: SFU.NewFlags, EMachine: Obj.Machine)) |
| 958 | return createFileError(F: Config.InputFilename, E: std::move(E)); |
| 959 | } |
| 960 | auto It2 = Config.SetSectionType.find(Key: Sec.Name); |
| 961 | if (It2 != Config.SetSectionType.end()) |
| 962 | setSectionType(Sec, Type: It2->second); |
| 963 | } |
| 964 | } |
| 965 | |
| 966 | if (!Config.SectionsToRename.empty()) { |
| 967 | std::vector<RelocationSectionBase *> RelocSections; |
| 968 | DenseSet<SectionBase *> RenamedSections; |
| 969 | for (SectionBase &Sec : Obj.sections()) { |
| 970 | auto *RelocSec = dyn_cast<RelocationSectionBase>(Val: &Sec); |
| 971 | const auto Iter = Config.SectionsToRename.find(Key: Sec.Name); |
| 972 | if (Iter != Config.SectionsToRename.end()) { |
| 973 | const SectionRename &SR = Iter->second; |
| 974 | Sec.Name = std::string(SR.NewName); |
| 975 | if (SR.NewFlags) { |
| 976 | if (Error E = setSectionFlagsAndType(Sec, Flags: *SR.NewFlags, EMachine: Obj.Machine)) |
| 977 | return createFileError(F: Config.InputFilename, E: std::move(E)); |
| 978 | } |
| 979 | RenamedSections.insert(V: &Sec); |
| 980 | } else if (RelocSec && !(Sec.Flags & SHF_ALLOC)) |
| 981 | // Postpone processing relocation sections which are not specified in |
| 982 | // their explicit '--rename-section' commands until after their target |
| 983 | // sections are renamed. |
| 984 | // Dynamic relocation sections (i.e. ones with SHF_ALLOC) should be |
| 985 | // renamed only explicitly. Otherwise, renaming, for example, '.got.plt' |
| 986 | // would affect '.rela.plt', which is not desirable. |
| 987 | RelocSections.push_back(x: RelocSec); |
| 988 | } |
| 989 | |
| 990 | // Rename relocation sections according to their target sections. |
| 991 | for (RelocationSectionBase *RelocSec : RelocSections) { |
| 992 | auto Iter = RenamedSections.find(V: RelocSec->getSection()); |
| 993 | if (Iter != RenamedSections.end()) |
| 994 | RelocSec->Name = (RelocSec->getNamePrefix() + (*Iter)->Name).str(); |
| 995 | } |
| 996 | } |
| 997 | |
| 998 | // Add a prefix to allocated sections and their relocation sections. This |
| 999 | // should be done after renaming the section by Config.SectionToRename to |
| 1000 | // imitate the GNU objcopy behavior. |
| 1001 | if (!Config.AllocSectionsPrefix.empty()) { |
| 1002 | DenseSet<SectionBase *> PrefixedSections; |
| 1003 | for (SectionBase &Sec : Obj.sections()) { |
| 1004 | if (Sec.Flags & SHF_ALLOC) { |
| 1005 | Sec.Name = (Config.AllocSectionsPrefix + Sec.Name).str(); |
| 1006 | PrefixedSections.insert(V: &Sec); |
| 1007 | } else if (auto *RelocSec = dyn_cast<RelocationSectionBase>(Val: &Sec)) { |
| 1008 | // Rename relocation sections associated to the allocated sections. |
| 1009 | // For example, if we rename .text to .prefix.text, we also rename |
| 1010 | // .rel.text to .rel.prefix.text. |
| 1011 | // |
| 1012 | // Dynamic relocation sections (SHT_REL[A] with SHF_ALLOC) are handled |
| 1013 | // above, e.g., .rela.plt is renamed to .prefix.rela.plt, not |
| 1014 | // .rela.prefix.plt since GNU objcopy does so. |
| 1015 | const SectionBase *TargetSec = RelocSec->getSection(); |
| 1016 | if (TargetSec && (TargetSec->Flags & SHF_ALLOC)) { |
| 1017 | // If the relocation section comes *after* the target section, we |
| 1018 | // don't add Config.AllocSectionsPrefix because we've already added |
| 1019 | // the prefix to TargetSec->Name. Otherwise, if the relocation |
| 1020 | // section comes *before* the target section, we add the prefix. |
| 1021 | if (PrefixedSections.count(V: TargetSec)) |
| 1022 | Sec.Name = (RelocSec->getNamePrefix() + TargetSec->Name).str(); |
| 1023 | else |
| 1024 | Sec.Name = (RelocSec->getNamePrefix() + Config.AllocSectionsPrefix + |
| 1025 | TargetSec->Name) |
| 1026 | .str(); |
| 1027 | } |
| 1028 | } |
| 1029 | } |
| 1030 | } |
| 1031 | |
| 1032 | if (ELFConfig.EntryExpr) |
| 1033 | Obj.Entry = ELFConfig.EntryExpr(Obj.Entry); |
| 1034 | return Error::success(); |
| 1035 | } |
| 1036 | |
| 1037 | static Error writeOutput(const CommonConfig &Config, Object &Obj, |
| 1038 | raw_ostream &Out, ElfType OutputElfType) { |
| 1039 | std::unique_ptr<Writer> Writer = |
| 1040 | createWriter(Config, Obj, Out, OutputElfType); |
| 1041 | if (Error E = Writer->finalize()) |
| 1042 | return E; |
| 1043 | return Writer->write(); |
| 1044 | } |
| 1045 | |
| 1046 | Error objcopy::elf::executeObjcopyOnIHex(const CommonConfig &Config, |
| 1047 | const ELFConfig &ELFConfig, |
| 1048 | MemoryBuffer &In, raw_ostream &Out) { |
| 1049 | IHexReader Reader(&In); |
| 1050 | Expected<std::unique_ptr<Object>> Obj = Reader.create(EnsureSymtab: true); |
| 1051 | if (!Obj) |
| 1052 | return Obj.takeError(); |
| 1053 | |
| 1054 | const ElfType OutputElfType = |
| 1055 | getOutputElfType(MI: Config.OutputArch.value_or(u: MachineInfo())); |
| 1056 | if (Error E = handleArgs(Config, ELFConfig, OutputElfType, Obj&: **Obj)) |
| 1057 | return E; |
| 1058 | return writeOutput(Config, Obj&: **Obj, Out, OutputElfType); |
| 1059 | } |
| 1060 | |
| 1061 | Error objcopy::elf::executeObjcopyOnRawBinary(const CommonConfig &Config, |
| 1062 | const ELFConfig &ELFConfig, |
| 1063 | MemoryBuffer &In, |
| 1064 | raw_ostream &Out) { |
| 1065 | BinaryReader Reader(&In, ELFConfig.NewSymbolVisibility); |
| 1066 | Expected<std::unique_ptr<Object>> Obj = Reader.create(EnsureSymtab: true); |
| 1067 | if (!Obj) |
| 1068 | return Obj.takeError(); |
| 1069 | |
| 1070 | // Prefer OutputArch (-O<format>) if set, otherwise fallback to BinaryArch |
| 1071 | // (-B<arch>). |
| 1072 | const ElfType OutputElfType = |
| 1073 | getOutputElfType(MI: Config.OutputArch.value_or(u: MachineInfo())); |
| 1074 | if (Error E = handleArgs(Config, ELFConfig, OutputElfType, Obj&: **Obj)) |
| 1075 | return E; |
| 1076 | return writeOutput(Config, Obj&: **Obj, Out, OutputElfType); |
| 1077 | } |
| 1078 | |
| 1079 | Error objcopy::elf::executeObjcopyOnBinary(const CommonConfig &Config, |
| 1080 | const ELFConfig &ELFConfig, |
| 1081 | object::ELFObjectFileBase &In, |
| 1082 | raw_ostream &Out) { |
| 1083 | ELFReader Reader(&In, Config.ExtractPartition); |
| 1084 | Expected<std::unique_ptr<Object>> Obj = |
| 1085 | Reader.create(EnsureSymtab: !Config.SymbolsToAdd.empty()); |
| 1086 | if (!Obj) |
| 1087 | return Obj.takeError(); |
| 1088 | // Prefer OutputArch (-O<format>) if set, otherwise infer it from the input. |
| 1089 | const ElfType OutputElfType = Config.OutputArch |
| 1090 | ? getOutputElfType(MI: *Config.OutputArch) |
| 1091 | : getOutputElfType(Bin: In); |
| 1092 | |
| 1093 | if (Error E = handleArgs(Config, ELFConfig, OutputElfType, Obj&: **Obj)) |
| 1094 | return E; |
| 1095 | |
| 1096 | if (Error E = writeOutput(Config, Obj&: **Obj, Out, OutputElfType)) |
| 1097 | return createFileError(F: Config.InputFilename, E: std::move(E)); |
| 1098 | |
| 1099 | return Error::success(); |
| 1100 | } |
| 1101 | |