| //===- MachOWriter.cpp ------------------------------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "MachOWriter.h" |
| #include "MachOLayoutBuilder.h" |
| #include "Object.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/BinaryFormat/MachO.h" |
| #include "llvm/Object/MachO.h" |
| #include "llvm/Support/Errc.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include <memory> |
| |
| namespace llvm { |
| namespace objcopy { |
| namespace macho { |
| |
| size_t MachOWriter::headerSize() const { |
| return Is64Bit ? sizeof(MachO::mach_header_64) : sizeof(MachO::mach_header); |
| } |
| |
| size_t MachOWriter::loadCommandsSize() const { return O.Header.SizeOfCmds; } |
| |
| size_t MachOWriter::symTableSize() const { |
| return O.SymTable.Symbols.size() * |
| (Is64Bit ? sizeof(MachO::nlist_64) : sizeof(MachO::nlist)); |
| } |
| |
| size_t MachOWriter::totalSize() const { |
| // Going from tail to head and looking for an appropriate "anchor" to |
| // calculate the total size assuming that all the offsets are either valid |
| // ("true") or 0 (0 indicates that the corresponding part is missing). |
| |
| SmallVector<size_t, 7> Ends; |
| if (O.SymTabCommandIndex) { |
| const MachO::symtab_command &SymTabCommand = |
| O.LoadCommands[*O.SymTabCommandIndex] |
| .MachOLoadCommand.symtab_command_data; |
| if (SymTabCommand.symoff) |
| Ends.push_back(SymTabCommand.symoff + symTableSize()); |
| if (SymTabCommand.stroff) |
| Ends.push_back(SymTabCommand.stroff + SymTabCommand.strsize); |
| } |
| if (O.DyLdInfoCommandIndex) { |
| const MachO::dyld_info_command &DyLdInfoCommand = |
| O.LoadCommands[*O.DyLdInfoCommandIndex] |
| .MachOLoadCommand.dyld_info_command_data; |
| if (DyLdInfoCommand.rebase_off) { |
| assert((DyLdInfoCommand.rebase_size == O.Rebases.Opcodes.size()) && |
| "Incorrect rebase opcodes size"); |
| Ends.push_back(DyLdInfoCommand.rebase_off + DyLdInfoCommand.rebase_size); |
| } |
| if (DyLdInfoCommand.bind_off) { |
| assert((DyLdInfoCommand.bind_size == O.Binds.Opcodes.size()) && |
| "Incorrect bind opcodes size"); |
| Ends.push_back(DyLdInfoCommand.bind_off + DyLdInfoCommand.bind_size); |
| } |
| if (DyLdInfoCommand.weak_bind_off) { |
| assert((DyLdInfoCommand.weak_bind_size == O.WeakBinds.Opcodes.size()) && |
| "Incorrect weak bind opcodes size"); |
| Ends.push_back(DyLdInfoCommand.weak_bind_off + |
| DyLdInfoCommand.weak_bind_size); |
| } |
| if (DyLdInfoCommand.lazy_bind_off) { |
| assert((DyLdInfoCommand.lazy_bind_size == O.LazyBinds.Opcodes.size()) && |
| "Incorrect lazy bind opcodes size"); |
| Ends.push_back(DyLdInfoCommand.lazy_bind_off + |
| DyLdInfoCommand.lazy_bind_size); |
| } |
| if (DyLdInfoCommand.export_off) { |
| assert((DyLdInfoCommand.export_size == O.Exports.Trie.size()) && |
| "Incorrect trie size"); |
| Ends.push_back(DyLdInfoCommand.export_off + DyLdInfoCommand.export_size); |
| } |
| } |
| |
| if (O.DySymTabCommandIndex) { |
| const MachO::dysymtab_command &DySymTabCommand = |
| O.LoadCommands[*O.DySymTabCommandIndex] |
| .MachOLoadCommand.dysymtab_command_data; |
| |
| if (DySymTabCommand.indirectsymoff) |
| Ends.push_back(DySymTabCommand.indirectsymoff + |
| sizeof(uint32_t) * O.IndirectSymTable.Symbols.size()); |
| } |
| |
| if (O.DataInCodeCommandIndex) { |
| const MachO::linkedit_data_command &LinkEditDataCommand = |
| O.LoadCommands[*O.DataInCodeCommandIndex] |
| .MachOLoadCommand.linkedit_data_command_data; |
| |
| if (LinkEditDataCommand.dataoff) |
| Ends.push_back(LinkEditDataCommand.dataoff + |
| LinkEditDataCommand.datasize); |
| } |
| |
| if (O.FunctionStartsCommandIndex) { |
| const MachO::linkedit_data_command &LinkEditDataCommand = |
| O.LoadCommands[*O.FunctionStartsCommandIndex] |
| .MachOLoadCommand.linkedit_data_command_data; |
| |
| if (LinkEditDataCommand.dataoff) |
| Ends.push_back(LinkEditDataCommand.dataoff + |
| LinkEditDataCommand.datasize); |
| } |
| |
| // Otherwise, use the last section / reloction. |
| for (const auto &LC : O.LoadCommands) |
| for (const auto &S : LC.Sections) { |
| Ends.push_back(S.Offset + S.Size); |
| if (S.RelOff) |
| Ends.push_back(S.RelOff + |
| S.NReloc * sizeof(MachO::any_relocation_info)); |
| } |
| |
| if (!Ends.empty()) |
| return *std::max_element(Ends.begin(), Ends.end()); |
| |
| // Otherwise, we have only Mach header and load commands. |
| return headerSize() + loadCommandsSize(); |
| } |
| |
| void MachOWriter::writeHeader() { |
| MachO::mach_header_64 Header; |
| |
| Header.magic = O.Header.Magic; |
| Header.cputype = O.Header.CPUType; |
| Header.cpusubtype = O.Header.CPUSubType; |
| Header.filetype = O.Header.FileType; |
| Header.ncmds = O.Header.NCmds; |
| Header.sizeofcmds = O.Header.SizeOfCmds; |
| Header.flags = O.Header.Flags; |
| Header.reserved = O.Header.Reserved; |
| |
| if (IsLittleEndian != sys::IsLittleEndianHost) |
| MachO::swapStruct(Header); |
| |
| auto HeaderSize = |
| Is64Bit ? sizeof(MachO::mach_header_64) : sizeof(MachO::mach_header); |
| memcpy(B.getBufferStart(), &Header, HeaderSize); |
| } |
| |
| void MachOWriter::writeLoadCommands() { |
| uint8_t *Begin = B.getBufferStart() + headerSize(); |
| for (const auto &LC : O.LoadCommands) { |
| // Construct a load command. |
| MachO::macho_load_command MLC = LC.MachOLoadCommand; |
| switch (MLC.load_command_data.cmd) { |
| case MachO::LC_SEGMENT: |
| if (IsLittleEndian != sys::IsLittleEndianHost) |
| MachO::swapStruct(MLC.segment_command_data); |
| memcpy(Begin, &MLC.segment_command_data, sizeof(MachO::segment_command)); |
| Begin += sizeof(MachO::segment_command); |
| |
| for (const auto &Sec : LC.Sections) |
| writeSectionInLoadCommand<MachO::section>(Sec, Begin); |
| continue; |
| case MachO::LC_SEGMENT_64: |
| if (IsLittleEndian != sys::IsLittleEndianHost) |
| MachO::swapStruct(MLC.segment_command_64_data); |
| memcpy(Begin, &MLC.segment_command_64_data, |
| sizeof(MachO::segment_command_64)); |
| Begin += sizeof(MachO::segment_command_64); |
| |
| for (const auto &Sec : LC.Sections) |
| writeSectionInLoadCommand<MachO::section_64>(Sec, Begin); |
| continue; |
| } |
| |
| #define HANDLE_LOAD_COMMAND(LCName, LCValue, LCStruct) \ |
| case MachO::LCName: \ |
| assert(sizeof(MachO::LCStruct) + LC.Payload.size() == \ |
| MLC.load_command_data.cmdsize); \ |
| if (IsLittleEndian != sys::IsLittleEndianHost) \ |
| MachO::swapStruct(MLC.LCStruct##_data); \ |
| memcpy(Begin, &MLC.LCStruct##_data, sizeof(MachO::LCStruct)); \ |
| Begin += sizeof(MachO::LCStruct); \ |
| memcpy(Begin, LC.Payload.data(), LC.Payload.size()); \ |
| Begin += LC.Payload.size(); \ |
| break; |
| |
| // Copy the load command as it is. |
| switch (MLC.load_command_data.cmd) { |
| default: |
| assert(sizeof(MachO::load_command) + LC.Payload.size() == |
| MLC.load_command_data.cmdsize); |
| if (IsLittleEndian != sys::IsLittleEndianHost) |
| MachO::swapStruct(MLC.load_command_data); |
| memcpy(Begin, &MLC.load_command_data, sizeof(MachO::load_command)); |
| Begin += sizeof(MachO::load_command); |
| memcpy(Begin, LC.Payload.data(), LC.Payload.size()); |
| Begin += LC.Payload.size(); |
| break; |
| #include "llvm/BinaryFormat/MachO.def" |
| } |
| } |
| } |
| |
| template <typename StructType> |
| void MachOWriter::writeSectionInLoadCommand(const Section &Sec, uint8_t *&Out) { |
| StructType Temp; |
| assert(Sec.Segname.size() <= sizeof(Temp.segname) && "too long segment name"); |
| assert(Sec.Sectname.size() <= sizeof(Temp.sectname) && |
| "too long section name"); |
| memset(&Temp, 0, sizeof(StructType)); |
| memcpy(Temp.segname, Sec.Segname.data(), Sec.Segname.size()); |
| memcpy(Temp.sectname, Sec.Sectname.data(), Sec.Sectname.size()); |
| Temp.addr = Sec.Addr; |
| Temp.size = Sec.Size; |
| Temp.offset = Sec.Offset; |
| Temp.align = Sec.Align; |
| Temp.reloff = Sec.RelOff; |
| Temp.nreloc = Sec.NReloc; |
| Temp.flags = Sec.Flags; |
| Temp.reserved1 = Sec.Reserved1; |
| Temp.reserved2 = Sec.Reserved2; |
| |
| if (IsLittleEndian != sys::IsLittleEndianHost) |
| MachO::swapStruct(Temp); |
| memcpy(Out, &Temp, sizeof(StructType)); |
| Out += sizeof(StructType); |
| } |
| |
| void MachOWriter::writeSections() { |
| for (const auto &LC : O.LoadCommands) |
| for (const auto &Sec : LC.Sections) { |
| if (Sec.isVirtualSection()) |
| continue; |
| |
| assert(Sec.Offset && "Section offset can not be zero"); |
| assert((Sec.Size == Sec.Content.size()) && "Incorrect section size"); |
| memcpy(B.getBufferStart() + Sec.Offset, Sec.Content.data(), |
| Sec.Content.size()); |
| for (size_t Index = 0; Index < Sec.Relocations.size(); ++Index) { |
| auto RelocInfo = Sec.Relocations[Index]; |
| if (!RelocInfo.Scattered) { |
| auto *Info = |
| reinterpret_cast<MachO::relocation_info *>(&RelocInfo.Info); |
| Info->r_symbolnum = RelocInfo.Symbol->Index; |
| } |
| |
| if (IsLittleEndian != sys::IsLittleEndianHost) |
| MachO::swapStruct( |
| reinterpret_cast<MachO::any_relocation_info &>(RelocInfo.Info)); |
| memcpy(B.getBufferStart() + Sec.RelOff + |
| Index * sizeof(MachO::any_relocation_info), |
| &RelocInfo.Info, sizeof(RelocInfo.Info)); |
| } |
| } |
| } |
| |
| template <typename NListType> |
| void writeNListEntry(const SymbolEntry &SE, bool IsLittleEndian, char *&Out, |
| uint32_t Nstrx) { |
| NListType ListEntry; |
| ListEntry.n_strx = Nstrx; |
| ListEntry.n_type = SE.n_type; |
| ListEntry.n_sect = SE.n_sect; |
| ListEntry.n_desc = SE.n_desc; |
| ListEntry.n_value = SE.n_value; |
| |
| if (IsLittleEndian != sys::IsLittleEndianHost) |
| MachO::swapStruct(ListEntry); |
| memcpy(Out, reinterpret_cast<const char *>(&ListEntry), sizeof(NListType)); |
| Out += sizeof(NListType); |
| } |
| |
| void MachOWriter::writeStringTable() { |
| if (!O.SymTabCommandIndex) |
| return; |
| const MachO::symtab_command &SymTabCommand = |
| O.LoadCommands[*O.SymTabCommandIndex] |
| .MachOLoadCommand.symtab_command_data; |
| |
| uint8_t *StrTable = (uint8_t *)B.getBufferStart() + SymTabCommand.stroff; |
| LayoutBuilder.getStringTableBuilder().write(StrTable); |
| } |
| |
| void MachOWriter::writeSymbolTable() { |
| if (!O.SymTabCommandIndex) |
| return; |
| const MachO::symtab_command &SymTabCommand = |
| O.LoadCommands[*O.SymTabCommandIndex] |
| .MachOLoadCommand.symtab_command_data; |
| |
| char *SymTable = (char *)B.getBufferStart() + SymTabCommand.symoff; |
| for (auto Iter = O.SymTable.Symbols.begin(), End = O.SymTable.Symbols.end(); |
| Iter != End; Iter++) { |
| SymbolEntry *Sym = Iter->get(); |
| uint32_t Nstrx = LayoutBuilder.getStringTableBuilder().getOffset(Sym->Name); |
| |
| if (Is64Bit) |
| writeNListEntry<MachO::nlist_64>(*Sym, IsLittleEndian, SymTable, Nstrx); |
| else |
| writeNListEntry<MachO::nlist>(*Sym, IsLittleEndian, SymTable, Nstrx); |
| } |
| } |
| |
| void MachOWriter::writeRebaseInfo() { |
| if (!O.DyLdInfoCommandIndex) |
| return; |
| const MachO::dyld_info_command &DyLdInfoCommand = |
| O.LoadCommands[*O.DyLdInfoCommandIndex] |
| .MachOLoadCommand.dyld_info_command_data; |
| char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.rebase_off; |
| assert((DyLdInfoCommand.rebase_size == O.Rebases.Opcodes.size()) && |
| "Incorrect rebase opcodes size"); |
| memcpy(Out, O.Rebases.Opcodes.data(), O.Rebases.Opcodes.size()); |
| } |
| |
| void MachOWriter::writeBindInfo() { |
| if (!O.DyLdInfoCommandIndex) |
| return; |
| const MachO::dyld_info_command &DyLdInfoCommand = |
| O.LoadCommands[*O.DyLdInfoCommandIndex] |
| .MachOLoadCommand.dyld_info_command_data; |
| char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.bind_off; |
| assert((DyLdInfoCommand.bind_size == O.Binds.Opcodes.size()) && |
| "Incorrect bind opcodes size"); |
| memcpy(Out, O.Binds.Opcodes.data(), O.Binds.Opcodes.size()); |
| } |
| |
| void MachOWriter::writeWeakBindInfo() { |
| if (!O.DyLdInfoCommandIndex) |
| return; |
| const MachO::dyld_info_command &DyLdInfoCommand = |
| O.LoadCommands[*O.DyLdInfoCommandIndex] |
| .MachOLoadCommand.dyld_info_command_data; |
| char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.weak_bind_off; |
| assert((DyLdInfoCommand.weak_bind_size == O.WeakBinds.Opcodes.size()) && |
| "Incorrect weak bind opcodes size"); |
| memcpy(Out, O.WeakBinds.Opcodes.data(), O.WeakBinds.Opcodes.size()); |
| } |
| |
| void MachOWriter::writeLazyBindInfo() { |
| if (!O.DyLdInfoCommandIndex) |
| return; |
| const MachO::dyld_info_command &DyLdInfoCommand = |
| O.LoadCommands[*O.DyLdInfoCommandIndex] |
| .MachOLoadCommand.dyld_info_command_data; |
| char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.lazy_bind_off; |
| assert((DyLdInfoCommand.lazy_bind_size == O.LazyBinds.Opcodes.size()) && |
| "Incorrect lazy bind opcodes size"); |
| memcpy(Out, O.LazyBinds.Opcodes.data(), O.LazyBinds.Opcodes.size()); |
| } |
| |
| void MachOWriter::writeExportInfo() { |
| if (!O.DyLdInfoCommandIndex) |
| return; |
| const MachO::dyld_info_command &DyLdInfoCommand = |
| O.LoadCommands[*O.DyLdInfoCommandIndex] |
| .MachOLoadCommand.dyld_info_command_data; |
| char *Out = (char *)B.getBufferStart() + DyLdInfoCommand.export_off; |
| assert((DyLdInfoCommand.export_size == O.Exports.Trie.size()) && |
| "Incorrect export trie size"); |
| memcpy(Out, O.Exports.Trie.data(), O.Exports.Trie.size()); |
| } |
| |
| void MachOWriter::writeIndirectSymbolTable() { |
| if (!O.DySymTabCommandIndex) |
| return; |
| |
| const MachO::dysymtab_command &DySymTabCommand = |
| O.LoadCommands[*O.DySymTabCommandIndex] |
| .MachOLoadCommand.dysymtab_command_data; |
| |
| char *Out = (char *)B.getBufferStart() + DySymTabCommand.indirectsymoff; |
| assert((DySymTabCommand.nindirectsyms == O.IndirectSymTable.Symbols.size()) && |
| "Incorrect indirect symbol table size"); |
| memcpy(Out, O.IndirectSymTable.Symbols.data(), |
| sizeof(uint32_t) * O.IndirectSymTable.Symbols.size()); |
| } |
| |
| void MachOWriter::writeDataInCodeData() { |
| if (!O.DataInCodeCommandIndex) |
| return; |
| const MachO::linkedit_data_command &LinkEditDataCommand = |
| O.LoadCommands[*O.DataInCodeCommandIndex] |
| .MachOLoadCommand.linkedit_data_command_data; |
| char *Out = (char *)B.getBufferStart() + LinkEditDataCommand.dataoff; |
| assert((LinkEditDataCommand.datasize == O.DataInCode.Data.size()) && |
| "Incorrect data in code data size"); |
| memcpy(Out, O.DataInCode.Data.data(), O.DataInCode.Data.size()); |
| } |
| |
| void MachOWriter::writeFunctionStartsData() { |
| if (!O.FunctionStartsCommandIndex) |
| return; |
| const MachO::linkedit_data_command &LinkEditDataCommand = |
| O.LoadCommands[*O.FunctionStartsCommandIndex] |
| .MachOLoadCommand.linkedit_data_command_data; |
| char *Out = (char *)B.getBufferStart() + LinkEditDataCommand.dataoff; |
| assert((LinkEditDataCommand.datasize == O.FunctionStarts.Data.size()) && |
| "Incorrect function starts data size"); |
| memcpy(Out, O.FunctionStarts.Data.data(), O.FunctionStarts.Data.size()); |
| } |
| |
| void MachOWriter::writeTail() { |
| typedef void (MachOWriter::*WriteHandlerType)(void); |
| typedef std::pair<uint64_t, WriteHandlerType> WriteOperation; |
| SmallVector<WriteOperation, 7> Queue; |
| |
| if (O.SymTabCommandIndex) { |
| const MachO::symtab_command &SymTabCommand = |
| O.LoadCommands[*O.SymTabCommandIndex] |
| .MachOLoadCommand.symtab_command_data; |
| if (SymTabCommand.symoff) |
| Queue.push_back({SymTabCommand.symoff, &MachOWriter::writeSymbolTable}); |
| if (SymTabCommand.stroff) |
| Queue.push_back({SymTabCommand.stroff, &MachOWriter::writeStringTable}); |
| } |
| |
| if (O.DyLdInfoCommandIndex) { |
| const MachO::dyld_info_command &DyLdInfoCommand = |
| O.LoadCommands[*O.DyLdInfoCommandIndex] |
| .MachOLoadCommand.dyld_info_command_data; |
| if (DyLdInfoCommand.rebase_off) |
| Queue.push_back( |
| {DyLdInfoCommand.rebase_off, &MachOWriter::writeRebaseInfo}); |
| if (DyLdInfoCommand.bind_off) |
| Queue.push_back({DyLdInfoCommand.bind_off, &MachOWriter::writeBindInfo}); |
| if (DyLdInfoCommand.weak_bind_off) |
| Queue.push_back( |
| {DyLdInfoCommand.weak_bind_off, &MachOWriter::writeWeakBindInfo}); |
| if (DyLdInfoCommand.lazy_bind_off) |
| Queue.push_back( |
| {DyLdInfoCommand.lazy_bind_off, &MachOWriter::writeLazyBindInfo}); |
| if (DyLdInfoCommand.export_off) |
| Queue.push_back( |
| {DyLdInfoCommand.export_off, &MachOWriter::writeExportInfo}); |
| } |
| |
| if (O.DySymTabCommandIndex) { |
| const MachO::dysymtab_command &DySymTabCommand = |
| O.LoadCommands[*O.DySymTabCommandIndex] |
| .MachOLoadCommand.dysymtab_command_data; |
| |
| if (DySymTabCommand.indirectsymoff) |
| Queue.emplace_back(DySymTabCommand.indirectsymoff, |
| &MachOWriter::writeIndirectSymbolTable); |
| } |
| |
| if (O.DataInCodeCommandIndex) { |
| const MachO::linkedit_data_command &LinkEditDataCommand = |
| O.LoadCommands[*O.DataInCodeCommandIndex] |
| .MachOLoadCommand.linkedit_data_command_data; |
| |
| if (LinkEditDataCommand.dataoff) |
| Queue.emplace_back(LinkEditDataCommand.dataoff, |
| &MachOWriter::writeDataInCodeData); |
| } |
| |
| if (O.FunctionStartsCommandIndex) { |
| const MachO::linkedit_data_command &LinkEditDataCommand = |
| O.LoadCommands[*O.FunctionStartsCommandIndex] |
| .MachOLoadCommand.linkedit_data_command_data; |
| |
| if (LinkEditDataCommand.dataoff) |
| Queue.emplace_back(LinkEditDataCommand.dataoff, |
| &MachOWriter::writeFunctionStartsData); |
| } |
| |
| llvm::sort(Queue, [](const WriteOperation &LHS, const WriteOperation &RHS) { |
| return LHS.first < RHS.first; |
| }); |
| |
| for (auto WriteOp : Queue) |
| (this->*WriteOp.second)(); |
| } |
| |
| Error MachOWriter::finalize() { return LayoutBuilder.layout(); } |
| |
| Error MachOWriter::write() { |
| if (Error E = B.allocate(totalSize())) |
| return E; |
| memset(B.getBufferStart(), 0, totalSize()); |
| writeHeader(); |
| writeLoadCommands(); |
| writeSections(); |
| writeTail(); |
| return B.commit(); |
| } |
| |
| } // end namespace macho |
| } // end namespace objcopy |
| } // end namespace llvm |
