2b2f4ae0fb
--change-section address and its alias --adjust-section-vma allows modification of section addresses in a relocatable file. This used to be used, for example, in Fiasco microkernel. On a relocatable file this option behaves the same as GNU objcopy, apart from the fact that it does not issue any warnings, for example, when an argument is not used. GNU objcopy does not produce an error when passed an executable file but the usecase for this is not clear, and the behaviour is inconsistent. The idea of GNU objcopy --change-section-address is that the option should change both LMA and VMA in an executable file. Since this patch does not implement executable file support, only VMA is changed.
993 lines
36 KiB
C++
993 lines
36 KiB
C++
//===- ELFObjcopy.cpp -----------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ObjCopy/ELF/ELFObjcopy.h"
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#include "ELFObject.h"
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#include "llvm/ADT/BitmaskEnum.h"
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/BinaryFormat/ELF.h"
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#include "llvm/MC/MCTargetOptions.h"
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#include "llvm/ObjCopy/CommonConfig.h"
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#include "llvm/ObjCopy/ELF/ELFConfig.h"
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#include "llvm/Object/Binary.h"
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#include "llvm/Object/ELFObjectFile.h"
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#include "llvm/Object/ELFTypes.h"
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#include "llvm/Object/Error.h"
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#include "llvm/Option/Option.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/Compression.h"
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#include "llvm/Support/Errc.h"
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#include "llvm/Support/Error.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/ErrorOr.h"
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#include "llvm/Support/FileSystem.h"
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#include "llvm/Support/Memory.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/raw_ostream.h"
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#include <algorithm>
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#include <cassert>
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#include <cstdlib>
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#include <functional>
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#include <iterator>
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#include <memory>
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#include <string>
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#include <system_error>
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#include <utility>
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using namespace llvm;
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using namespace llvm::ELF;
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using namespace llvm::objcopy;
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using namespace llvm::objcopy::elf;
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using namespace llvm::object;
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using SectionPred = std::function<bool(const SectionBase &Sec)>;
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static bool isDebugSection(const SectionBase &Sec) {
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return StringRef(Sec.Name).starts_with(".debug") || Sec.Name == ".gdb_index";
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}
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static bool isDWOSection(const SectionBase &Sec) {
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return StringRef(Sec.Name).ends_with(".dwo");
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}
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static bool onlyKeepDWOPred(const Object &Obj, const SectionBase &Sec) {
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// We can't remove the section header string table.
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if (&Sec == Obj.SectionNames)
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return false;
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// Short of keeping the string table we want to keep everything that is a DWO
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// section and remove everything else.
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return !isDWOSection(Sec);
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}
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static Expected<uint64_t> getNewShfFlags(SectionFlag AllFlags,
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uint16_t EMachine) {
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uint64_t NewFlags = 0;
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if (AllFlags & SectionFlag::SecAlloc)
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NewFlags |= ELF::SHF_ALLOC;
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if (!(AllFlags & SectionFlag::SecReadonly))
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NewFlags |= ELF::SHF_WRITE;
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if (AllFlags & SectionFlag::SecCode)
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NewFlags |= ELF::SHF_EXECINSTR;
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if (AllFlags & SectionFlag::SecMerge)
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NewFlags |= ELF::SHF_MERGE;
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if (AllFlags & SectionFlag::SecStrings)
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NewFlags |= ELF::SHF_STRINGS;
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if (AllFlags & SectionFlag::SecExclude)
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NewFlags |= ELF::SHF_EXCLUDE;
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if (AllFlags & SectionFlag::SecLarge) {
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if (EMachine != EM_X86_64)
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return createStringError(errc::invalid_argument,
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"section flag SHF_X86_64_LARGE can only be used "
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"with x86_64 architecture");
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NewFlags |= ELF::SHF_X86_64_LARGE;
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}
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return NewFlags;
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}
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static uint64_t getSectionFlagsPreserveMask(uint64_t OldFlags,
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uint64_t NewFlags,
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uint16_t EMachine) {
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// Preserve some flags which should not be dropped when setting flags.
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// Also, preserve anything OS/processor dependant.
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const uint64_t PreserveMask =
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(ELF::SHF_COMPRESSED | ELF::SHF_GROUP | ELF::SHF_LINK_ORDER |
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ELF::SHF_MASKOS | ELF::SHF_MASKPROC | ELF::SHF_TLS |
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ELF::SHF_INFO_LINK) &
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~ELF::SHF_EXCLUDE &
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~(EMachine == EM_X86_64 ? (uint64_t)ELF::SHF_X86_64_LARGE : 0UL);
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return (OldFlags & PreserveMask) | (NewFlags & ~PreserveMask);
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}
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static void setSectionType(SectionBase &Sec, uint64_t Type) {
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// If Sec's type is changed from SHT_NOBITS due to --set-section-flags,
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// Offset may not be aligned. Align it to max(Align, 1).
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if (Sec.Type == ELF::SHT_NOBITS && Type != ELF::SHT_NOBITS)
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Sec.Offset = alignTo(Sec.Offset, std::max(Sec.Align, uint64_t(1)));
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Sec.Type = Type;
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}
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static Error setSectionFlagsAndType(SectionBase &Sec, SectionFlag Flags,
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uint16_t EMachine) {
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Expected<uint64_t> NewFlags = getNewShfFlags(Flags, EMachine);
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if (!NewFlags)
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return NewFlags.takeError();
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Sec.Flags = getSectionFlagsPreserveMask(Sec.Flags, *NewFlags, EMachine);
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// In GNU objcopy, certain flags promote SHT_NOBITS to SHT_PROGBITS. This rule
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// may promote more non-ALLOC sections than GNU objcopy, but it is fine as
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// non-ALLOC SHT_NOBITS sections do not make much sense.
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if (Sec.Type == SHT_NOBITS &&
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(!(Sec.Flags & ELF::SHF_ALLOC) ||
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Flags & (SectionFlag::SecContents | SectionFlag::SecLoad)))
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setSectionType(Sec, ELF::SHT_PROGBITS);
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return Error::success();
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}
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static ElfType getOutputElfType(const Binary &Bin) {
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// Infer output ELF type from the input ELF object
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if (isa<ELFObjectFile<ELF32LE>>(Bin))
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return ELFT_ELF32LE;
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if (isa<ELFObjectFile<ELF64LE>>(Bin))
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return ELFT_ELF64LE;
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if (isa<ELFObjectFile<ELF32BE>>(Bin))
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return ELFT_ELF32BE;
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if (isa<ELFObjectFile<ELF64BE>>(Bin))
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return ELFT_ELF64BE;
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llvm_unreachable("Invalid ELFType");
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}
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static ElfType getOutputElfType(const MachineInfo &MI) {
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// Infer output ELF type from the binary arch specified
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if (MI.Is64Bit)
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return MI.IsLittleEndian ? ELFT_ELF64LE : ELFT_ELF64BE;
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else
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return MI.IsLittleEndian ? ELFT_ELF32LE : ELFT_ELF32BE;
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}
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static std::unique_ptr<Writer> createELFWriter(const CommonConfig &Config,
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Object &Obj, raw_ostream &Out,
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ElfType OutputElfType) {
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// Depending on the initial ELFT and OutputFormat we need a different Writer.
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switch (OutputElfType) {
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case ELFT_ELF32LE:
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return std::make_unique<ELFWriter<ELF32LE>>(Obj, Out, !Config.StripSections,
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Config.OnlyKeepDebug);
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case ELFT_ELF64LE:
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return std::make_unique<ELFWriter<ELF64LE>>(Obj, Out, !Config.StripSections,
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Config.OnlyKeepDebug);
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case ELFT_ELF32BE:
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return std::make_unique<ELFWriter<ELF32BE>>(Obj, Out, !Config.StripSections,
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Config.OnlyKeepDebug);
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case ELFT_ELF64BE:
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return std::make_unique<ELFWriter<ELF64BE>>(Obj, Out, !Config.StripSections,
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Config.OnlyKeepDebug);
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}
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llvm_unreachable("Invalid output format");
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}
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static std::unique_ptr<Writer> createWriter(const CommonConfig &Config,
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Object &Obj, raw_ostream &Out,
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ElfType OutputElfType) {
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switch (Config.OutputFormat) {
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case FileFormat::Binary:
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return std::make_unique<BinaryWriter>(Obj, Out, Config);
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case FileFormat::IHex:
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return std::make_unique<IHexWriter>(Obj, Out, Config.OutputFilename);
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case FileFormat::SREC:
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return std::make_unique<SRECWriter>(Obj, Out, Config.OutputFilename);
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default:
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return createELFWriter(Config, Obj, Out, OutputElfType);
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}
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}
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static Error dumpSectionToFile(StringRef SecName, StringRef Filename,
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Object &Obj) {
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for (auto &Sec : Obj.sections()) {
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if (Sec.Name == SecName) {
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if (Sec.Type == SHT_NOBITS)
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return createStringError(object_error::parse_failed,
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"cannot dump section '%s': it has no contents",
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SecName.str().c_str());
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Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
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FileOutputBuffer::create(Filename, Sec.OriginalData.size());
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if (!BufferOrErr)
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return BufferOrErr.takeError();
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std::unique_ptr<FileOutputBuffer> Buf = std::move(*BufferOrErr);
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std::copy(Sec.OriginalData.begin(), Sec.OriginalData.end(),
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Buf->getBufferStart());
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if (Error E = Buf->commit())
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return E;
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return Error::success();
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}
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}
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return createStringError(object_error::parse_failed, "section '%s' not found",
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SecName.str().c_str());
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}
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Error Object::compressOrDecompressSections(const CommonConfig &Config) {
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// Build a list of sections we are going to replace.
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// We can't call `addSection` while iterating over sections,
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// because it would mutate the sections array.
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SmallVector<std::pair<SectionBase *, std::function<SectionBase *()>>, 0>
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ToReplace;
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for (SectionBase &Sec : sections()) {
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std::optional<DebugCompressionType> CType;
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for (auto &[Matcher, T] : Config.compressSections)
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if (Matcher.matches(Sec.Name))
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CType = T;
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// Handle --compress-debug-sections and --decompress-debug-sections, which
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// apply to non-ALLOC debug sections.
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if (!(Sec.Flags & SHF_ALLOC) && StringRef(Sec.Name).starts_with(".debug")) {
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if (Config.CompressionType != DebugCompressionType::None)
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CType = Config.CompressionType;
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else if (Config.DecompressDebugSections)
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CType = DebugCompressionType::None;
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}
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if (!CType)
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continue;
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if (Sec.ParentSegment)
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return createStringError(
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errc::invalid_argument,
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"section '" + Sec.Name +
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"' within a segment cannot be (de)compressed");
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if (auto *CS = dyn_cast<CompressedSection>(&Sec)) {
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if (*CType == DebugCompressionType::None)
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ToReplace.emplace_back(
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&Sec, [=] { return &addSection<DecompressedSection>(*CS); });
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} else if (*CType != DebugCompressionType::None) {
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ToReplace.emplace_back(&Sec, [=, S = &Sec] {
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return &addSection<CompressedSection>(
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CompressedSection(*S, *CType, Is64Bits));
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});
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}
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}
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DenseMap<SectionBase *, SectionBase *> FromTo;
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for (auto [S, Func] : ToReplace)
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FromTo[S] = Func();
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return replaceSections(FromTo);
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}
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static bool isAArch64MappingSymbol(const Symbol &Sym) {
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if (Sym.Binding != STB_LOCAL || Sym.Type != STT_NOTYPE ||
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Sym.getShndx() == SHN_UNDEF)
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return false;
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StringRef Name = Sym.Name;
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if (!Name.consume_front("$x") && !Name.consume_front("$d"))
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return false;
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return Name.empty() || Name.starts_with(".");
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}
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static bool isArmMappingSymbol(const Symbol &Sym) {
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if (Sym.Binding != STB_LOCAL || Sym.Type != STT_NOTYPE ||
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Sym.getShndx() == SHN_UNDEF)
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return false;
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StringRef Name = Sym.Name;
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if (!Name.consume_front("$a") && !Name.consume_front("$d") &&
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!Name.consume_front("$t"))
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return false;
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return Name.empty() || Name.starts_with(".");
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}
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// Check if the symbol should be preserved because it is required by ABI.
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static bool isRequiredByABISymbol(const Object &Obj, const Symbol &Sym) {
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switch (Obj.Machine) {
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case EM_AARCH64:
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// Mapping symbols should be preserved for a relocatable object file.
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return Obj.isRelocatable() && isAArch64MappingSymbol(Sym);
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case EM_ARM:
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// Mapping symbols should be preserved for a relocatable object file.
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return Obj.isRelocatable() && isArmMappingSymbol(Sym);
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default:
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return false;
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}
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}
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static bool isUnneededSymbol(const Symbol &Sym) {
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return !Sym.Referenced &&
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(Sym.Binding == STB_LOCAL || Sym.getShndx() == SHN_UNDEF) &&
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Sym.Type != STT_SECTION;
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}
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static Error updateAndRemoveSymbols(const CommonConfig &Config,
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const ELFConfig &ELFConfig, Object &Obj) {
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// TODO: update or remove symbols only if there is an option that affects
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// them.
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if (!Obj.SymbolTable)
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return Error::success();
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Obj.SymbolTable->updateSymbols([&](Symbol &Sym) {
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if (Config.SymbolsToSkip.matches(Sym.Name))
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return;
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// Common and undefined symbols don't make sense as local symbols, and can
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// even cause crashes if we localize those, so skip them.
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if (!Sym.isCommon() && Sym.getShndx() != SHN_UNDEF &&
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((ELFConfig.LocalizeHidden &&
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(Sym.Visibility == STV_HIDDEN || Sym.Visibility == STV_INTERNAL)) ||
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Config.SymbolsToLocalize.matches(Sym.Name)))
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Sym.Binding = STB_LOCAL;
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for (auto &[Matcher, Visibility] : ELFConfig.SymbolsToSetVisibility)
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if (Matcher.matches(Sym.Name))
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Sym.Visibility = Visibility;
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// Note: these two globalize flags have very similar names but different
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// meanings:
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//
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// --globalize-symbol: promote a symbol to global
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// --keep-global-symbol: all symbols except for these should be made local
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//
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// If --globalize-symbol is specified for a given symbol, it will be
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// global in the output file even if it is not included via
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// --keep-global-symbol. Because of that, make sure to check
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// --globalize-symbol second.
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if (!Config.SymbolsToKeepGlobal.empty() &&
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!Config.SymbolsToKeepGlobal.matches(Sym.Name) &&
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Sym.getShndx() != SHN_UNDEF)
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Sym.Binding = STB_LOCAL;
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if (Config.SymbolsToGlobalize.matches(Sym.Name) &&
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Sym.getShndx() != SHN_UNDEF)
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Sym.Binding = STB_GLOBAL;
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// SymbolsToWeaken applies to both STB_GLOBAL and STB_GNU_UNIQUE.
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if (Config.SymbolsToWeaken.matches(Sym.Name) && Sym.Binding != STB_LOCAL)
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Sym.Binding = STB_WEAK;
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if (Config.Weaken && Sym.Binding != STB_LOCAL &&
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Sym.getShndx() != SHN_UNDEF)
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Sym.Binding = STB_WEAK;
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const auto I = Config.SymbolsToRename.find(Sym.Name);
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if (I != Config.SymbolsToRename.end())
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Sym.Name = std::string(I->getValue());
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if (!Config.SymbolsPrefixRemove.empty() && Sym.Type != STT_SECTION)
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if (Sym.Name.compare(0, Config.SymbolsPrefixRemove.size(),
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Config.SymbolsPrefixRemove) == 0)
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Sym.Name = Sym.Name.substr(Config.SymbolsPrefixRemove.size());
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if (!Config.SymbolsPrefix.empty() && Sym.Type != STT_SECTION)
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Sym.Name = (Config.SymbolsPrefix + Sym.Name).str();
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});
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// The purpose of this loop is to mark symbols referenced by sections
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// (like GroupSection or RelocationSection). This way, we know which
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// symbols are still 'needed' and which are not.
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if (Config.StripUnneeded || !Config.UnneededSymbolsToRemove.empty() ||
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!Config.OnlySection.empty()) {
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for (SectionBase &Sec : Obj.sections())
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Sec.markSymbols();
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}
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auto RemoveSymbolsPred = [&](const Symbol &Sym) {
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if (Config.SymbolsToKeep.matches(Sym.Name) ||
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(ELFConfig.KeepFileSymbols && Sym.Type == STT_FILE))
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return false;
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if (Config.SymbolsToRemove.matches(Sym.Name))
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return true;
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if (Config.StripAll || Config.StripAllGNU)
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return true;
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if (isRequiredByABISymbol(Obj, Sym))
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return false;
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if (Config.StripDebug && Sym.Type == STT_FILE)
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return true;
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if ((Config.DiscardMode == DiscardType::All ||
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(Config.DiscardMode == DiscardType::Locals &&
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StringRef(Sym.Name).starts_with(".L"))) &&
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Sym.Binding == STB_LOCAL && Sym.getShndx() != SHN_UNDEF &&
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Sym.Type != STT_FILE && Sym.Type != STT_SECTION)
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return true;
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if ((Config.StripUnneeded ||
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Config.UnneededSymbolsToRemove.matches(Sym.Name)) &&
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(!Obj.isRelocatable() || isUnneededSymbol(Sym)))
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return true;
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// We want to remove undefined symbols if all references have been stripped.
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if (!Config.OnlySection.empty() && !Sym.Referenced &&
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Sym.getShndx() == SHN_UNDEF)
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return true;
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return false;
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};
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return Obj.removeSymbols(RemoveSymbolsPred);
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}
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static Error replaceAndRemoveSections(const CommonConfig &Config,
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const ELFConfig &ELFConfig, Object &Obj) {
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SectionPred RemovePred = [](const SectionBase &) { return false; };
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// Removes:
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if (!Config.ToRemove.empty()) {
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RemovePred = [&Config](const SectionBase &Sec) {
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return Config.ToRemove.matches(Sec.Name);
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};
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}
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if (Config.StripDWO)
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RemovePred = [RemovePred](const SectionBase &Sec) {
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return isDWOSection(Sec) || RemovePred(Sec);
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};
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if (Config.ExtractDWO)
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RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
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return onlyKeepDWOPred(Obj, Sec) || RemovePred(Sec);
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};
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if (Config.StripAllGNU)
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RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
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if (RemovePred(Sec))
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return true;
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if ((Sec.Flags & SHF_ALLOC) != 0)
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return false;
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if (&Sec == Obj.SectionNames)
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return false;
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switch (Sec.Type) {
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case SHT_SYMTAB:
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case SHT_REL:
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case SHT_RELA:
|
|
case SHT_STRTAB:
|
|
return true;
|
|
}
|
|
return isDebugSection(Sec);
|
|
};
|
|
|
|
if (Config.StripSections) {
|
|
RemovePred = [RemovePred](const SectionBase &Sec) {
|
|
return RemovePred(Sec) || Sec.ParentSegment == nullptr;
|
|
};
|
|
}
|
|
|
|
if (Config.StripDebug || Config.StripUnneeded) {
|
|
RemovePred = [RemovePred](const SectionBase &Sec) {
|
|
return RemovePred(Sec) || isDebugSection(Sec);
|
|
};
|
|
}
|
|
|
|
if (Config.StripNonAlloc)
|
|
RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
|
|
if (RemovePred(Sec))
|
|
return true;
|
|
if (&Sec == Obj.SectionNames)
|
|
return false;
|
|
return (Sec.Flags & SHF_ALLOC) == 0 && Sec.ParentSegment == nullptr;
|
|
};
|
|
|
|
if (Config.StripAll)
|
|
RemovePred = [RemovePred, &Obj](const SectionBase &Sec) {
|
|
if (RemovePred(Sec))
|
|
return true;
|
|
if (&Sec == Obj.SectionNames)
|
|
return false;
|
|
if (StringRef(Sec.Name).starts_with(".gnu.warning"))
|
|
return false;
|
|
if (StringRef(Sec.Name).starts_with(".gnu_debuglink"))
|
|
return false;
|
|
// We keep the .ARM.attribute section to maintain compatibility
|
|
// with Debian derived distributions. This is a bug in their
|
|
// patchset as documented here:
|
|
// https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=943798
|
|
if (Sec.Type == SHT_ARM_ATTRIBUTES)
|
|
return false;
|
|
if (Sec.ParentSegment != nullptr)
|
|
return false;
|
|
return (Sec.Flags & SHF_ALLOC) == 0;
|
|
};
|
|
|
|
if (Config.ExtractPartition || Config.ExtractMainPartition) {
|
|
RemovePred = [RemovePred](const SectionBase &Sec) {
|
|
if (RemovePred(Sec))
|
|
return true;
|
|
if (Sec.Type == SHT_LLVM_PART_EHDR || Sec.Type == SHT_LLVM_PART_PHDR)
|
|
return true;
|
|
return (Sec.Flags & SHF_ALLOC) != 0 && !Sec.ParentSegment;
|
|
};
|
|
}
|
|
|
|
// Explicit copies:
|
|
if (!Config.OnlySection.empty()) {
|
|
RemovePred = [&Config, RemovePred, &Obj](const SectionBase &Sec) {
|
|
// Explicitly keep these sections regardless of previous removes.
|
|
if (Config.OnlySection.matches(Sec.Name))
|
|
return false;
|
|
|
|
// Allow all implicit removes.
|
|
if (RemovePred(Sec))
|
|
return true;
|
|
|
|
// Keep special sections.
|
|
if (Obj.SectionNames == &Sec)
|
|
return false;
|
|
if (Obj.SymbolTable == &Sec ||
|
|
(Obj.SymbolTable && Obj.SymbolTable->getStrTab() == &Sec))
|
|
return false;
|
|
|
|
// Remove everything else.
|
|
return true;
|
|
};
|
|
}
|
|
|
|
if (!Config.KeepSection.empty()) {
|
|
RemovePred = [&Config, RemovePred](const SectionBase &Sec) {
|
|
// Explicitly keep these sections regardless of previous removes.
|
|
if (Config.KeepSection.matches(Sec.Name))
|
|
return false;
|
|
// Otherwise defer to RemovePred.
|
|
return RemovePred(Sec);
|
|
};
|
|
}
|
|
|
|
// This has to be the last predicate assignment.
|
|
// If the option --keep-symbol has been specified
|
|
// and at least one of those symbols is present
|
|
// (equivalently, the updated symbol table is not empty)
|
|
// the symbol table and the string table should not be removed.
|
|
if ((!Config.SymbolsToKeep.empty() || ELFConfig.KeepFileSymbols) &&
|
|
Obj.SymbolTable && !Obj.SymbolTable->empty()) {
|
|
RemovePred = [&Obj, RemovePred](const SectionBase &Sec) {
|
|
if (&Sec == Obj.SymbolTable || &Sec == Obj.SymbolTable->getStrTab())
|
|
return false;
|
|
return RemovePred(Sec);
|
|
};
|
|
}
|
|
|
|
if (Error E = Obj.removeSections(ELFConfig.AllowBrokenLinks, RemovePred))
|
|
return E;
|
|
|
|
if (Error E = Obj.compressOrDecompressSections(Config))
|
|
return E;
|
|
|
|
return Error::success();
|
|
}
|
|
|
|
// Add symbol to the Object symbol table with the specified properties.
|
|
static void addSymbol(Object &Obj, const NewSymbolInfo &SymInfo,
|
|
uint8_t DefaultVisibility) {
|
|
SectionBase *Sec = Obj.findSection(SymInfo.SectionName);
|
|
uint64_t Value = Sec ? Sec->Addr + SymInfo.Value : SymInfo.Value;
|
|
|
|
uint8_t Bind = ELF::STB_GLOBAL;
|
|
uint8_t Type = ELF::STT_NOTYPE;
|
|
uint8_t Visibility = DefaultVisibility;
|
|
|
|
for (SymbolFlag FlagValue : SymInfo.Flags)
|
|
switch (FlagValue) {
|
|
case SymbolFlag::Global:
|
|
Bind = ELF::STB_GLOBAL;
|
|
break;
|
|
case SymbolFlag::Local:
|
|
Bind = ELF::STB_LOCAL;
|
|
break;
|
|
case SymbolFlag::Weak:
|
|
Bind = ELF::STB_WEAK;
|
|
break;
|
|
case SymbolFlag::Default:
|
|
Visibility = ELF::STV_DEFAULT;
|
|
break;
|
|
case SymbolFlag::Hidden:
|
|
Visibility = ELF::STV_HIDDEN;
|
|
break;
|
|
case SymbolFlag::Protected:
|
|
Visibility = ELF::STV_PROTECTED;
|
|
break;
|
|
case SymbolFlag::File:
|
|
Type = ELF::STT_FILE;
|
|
break;
|
|
case SymbolFlag::Section:
|
|
Type = ELF::STT_SECTION;
|
|
break;
|
|
case SymbolFlag::Object:
|
|
Type = ELF::STT_OBJECT;
|
|
break;
|
|
case SymbolFlag::Function:
|
|
Type = ELF::STT_FUNC;
|
|
break;
|
|
case SymbolFlag::IndirectFunction:
|
|
Type = ELF::STT_GNU_IFUNC;
|
|
break;
|
|
default: /* Other flag values are ignored for ELF. */
|
|
break;
|
|
};
|
|
|
|
Obj.SymbolTable->addSymbol(
|
|
SymInfo.SymbolName, Bind, Type, Sec, Value, Visibility,
|
|
Sec ? (uint16_t)SYMBOL_SIMPLE_INDEX : (uint16_t)SHN_ABS, 0);
|
|
}
|
|
|
|
static Error
|
|
handleUserSection(const NewSectionInfo &NewSection,
|
|
function_ref<Error(StringRef, ArrayRef<uint8_t>)> F) {
|
|
ArrayRef<uint8_t> Data(reinterpret_cast<const uint8_t *>(
|
|
NewSection.SectionData->getBufferStart()),
|
|
NewSection.SectionData->getBufferSize());
|
|
return F(NewSection.SectionName, Data);
|
|
}
|
|
|
|
static Error verifyNoteSection(StringRef Name, endianness Endianness,
|
|
ArrayRef<uint8_t> Data) {
|
|
// An ELF note has the following structure:
|
|
// Name Size: 4 bytes (integer)
|
|
// Desc Size: 4 bytes (integer)
|
|
// Type : 4 bytes
|
|
// Name : variable size, padded to a 4 byte boundary
|
|
// Desc : variable size, padded to a 4 byte boundary
|
|
|
|
if (Data.empty())
|
|
return Error::success();
|
|
|
|
if (Data.size() < 12) {
|
|
std::string msg;
|
|
raw_string_ostream(msg)
|
|
<< Name << " data must be either empty or at least 12 bytes long";
|
|
return createStringError(errc::invalid_argument, msg);
|
|
}
|
|
if (Data.size() % 4 != 0) {
|
|
std::string msg;
|
|
raw_string_ostream(msg)
|
|
<< Name << " data size must be a multiple of 4 bytes";
|
|
return createStringError(errc::invalid_argument, msg);
|
|
}
|
|
ArrayRef<uint8_t> NameSize = Data.slice(0, 4);
|
|
ArrayRef<uint8_t> DescSize = Data.slice(4, 4);
|
|
|
|
uint32_t NameSizeValue = support::endian::read32(NameSize.data(), Endianness);
|
|
uint32_t DescSizeValue = support::endian::read32(DescSize.data(), Endianness);
|
|
|
|
uint64_t ExpectedDataSize =
|
|
/*NameSize=*/4 + /*DescSize=*/4 + /*Type=*/4 +
|
|
/*Name=*/alignTo(NameSizeValue, 4) +
|
|
/*Desc=*/alignTo(DescSizeValue, 4);
|
|
uint64_t ActualDataSize = Data.size();
|
|
if (ActualDataSize != ExpectedDataSize) {
|
|
std::string msg;
|
|
raw_string_ostream(msg)
|
|
<< Name
|
|
<< " data size is incompatible with the content of "
|
|
"the name and description size fields:"
|
|
<< " expecting " << ExpectedDataSize << ", found " << ActualDataSize;
|
|
return createStringError(errc::invalid_argument, msg);
|
|
}
|
|
|
|
return Error::success();
|
|
}
|
|
|
|
// This function handles the high level operations of GNU objcopy including
|
|
// handling command line options. It's important to outline certain properties
|
|
// we expect to hold of the command line operations. Any operation that "keeps"
|
|
// should keep regardless of a remove. Additionally any removal should respect
|
|
// any previous removals. Lastly whether or not something is removed shouldn't
|
|
// depend a) on the order the options occur in or b) on some opaque priority
|
|
// system. The only priority is that keeps/copies overrule removes.
|
|
static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
|
|
ElfType OutputElfType, Object &Obj) {
|
|
if (Config.OutputArch) {
|
|
Obj.Machine = Config.OutputArch->EMachine;
|
|
Obj.OSABI = Config.OutputArch->OSABI;
|
|
}
|
|
|
|
if (!Config.SplitDWO.empty() && Config.ExtractDWO) {
|
|
return Obj.removeSections(
|
|
ELFConfig.AllowBrokenLinks,
|
|
[&Obj](const SectionBase &Sec) { return onlyKeepDWOPred(Obj, Sec); });
|
|
}
|
|
|
|
// Dump sections before add/remove for compatibility with GNU objcopy.
|
|
for (StringRef Flag : Config.DumpSection) {
|
|
StringRef SectionName;
|
|
StringRef FileName;
|
|
std::tie(SectionName, FileName) = Flag.split('=');
|
|
if (Error E = dumpSectionToFile(SectionName, FileName, Obj))
|
|
return E;
|
|
}
|
|
|
|
// It is important to remove the sections first. For example, we want to
|
|
// remove the relocation sections before removing the symbols. That allows
|
|
// us to avoid reporting the inappropriate errors about removing symbols
|
|
// named in relocations.
|
|
if (Error E = replaceAndRemoveSections(Config, ELFConfig, Obj))
|
|
return E;
|
|
|
|
if (Error E = updateAndRemoveSymbols(Config, ELFConfig, Obj))
|
|
return E;
|
|
|
|
if (!Config.SetSectionAlignment.empty()) {
|
|
for (SectionBase &Sec : Obj.sections()) {
|
|
auto I = Config.SetSectionAlignment.find(Sec.Name);
|
|
if (I != Config.SetSectionAlignment.end())
|
|
Sec.Align = I->second;
|
|
}
|
|
}
|
|
|
|
if (Config.ChangeSectionLMAValAll != 0) {
|
|
for (Segment &Seg : Obj.segments()) {
|
|
if (Seg.FileSize > 0) {
|
|
if (Config.ChangeSectionLMAValAll > 0 &&
|
|
Seg.PAddr > std::numeric_limits<uint64_t>::max() -
|
|
Config.ChangeSectionLMAValAll) {
|
|
return createStringError(
|
|
errc::invalid_argument,
|
|
"address 0x" + Twine::utohexstr(Seg.PAddr) +
|
|
" cannot be increased by 0x" +
|
|
Twine::utohexstr(Config.ChangeSectionLMAValAll) +
|
|
". The result would overflow");
|
|
} else if (Config.ChangeSectionLMAValAll < 0 &&
|
|
Seg.PAddr < std::numeric_limits<uint64_t>::min() -
|
|
Config.ChangeSectionLMAValAll) {
|
|
return createStringError(
|
|
errc::invalid_argument,
|
|
"address 0x" + Twine::utohexstr(Seg.PAddr) +
|
|
" cannot be decreased by 0x" +
|
|
Twine::utohexstr(std::abs(Config.ChangeSectionLMAValAll)) +
|
|
". The result would underflow");
|
|
}
|
|
Seg.PAddr += Config.ChangeSectionLMAValAll;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!Config.ChangeSectionAddress.empty()) {
|
|
if (Obj.Type != ELF::ET_REL)
|
|
return createStringError(
|
|
object_error::invalid_file_type,
|
|
"cannot change section address in a non-relocatable file");
|
|
|
|
StringMap<AddressUpdate> SectionsToUpdateAddress;
|
|
for (const SectionPatternAddressUpdate &PatternUpdate :
|
|
make_range(Config.ChangeSectionAddress.rbegin(),
|
|
Config.ChangeSectionAddress.rend())) {
|
|
for (SectionBase &Sec : Obj.sections()) {
|
|
if (PatternUpdate.SectionPattern.matches(Sec.Name) &&
|
|
SectionsToUpdateAddress.try_emplace(Sec.Name, PatternUpdate.Update)
|
|
.second) {
|
|
if (PatternUpdate.Update.Kind == AdjustKind::Subtract &&
|
|
Sec.Addr < PatternUpdate.Update.Value) {
|
|
return createStringError(
|
|
errc::invalid_argument,
|
|
"address 0x" + Twine::utohexstr(Sec.Addr) +
|
|
" cannot be decreased by 0x" +
|
|
Twine::utohexstr(PatternUpdate.Update.Value) +
|
|
". The result would underflow");
|
|
}
|
|
if (PatternUpdate.Update.Kind == AdjustKind::Add &&
|
|
Sec.Addr > std::numeric_limits<uint64_t>::max() -
|
|
PatternUpdate.Update.Value) {
|
|
return createStringError(
|
|
errc::invalid_argument,
|
|
"address 0x" + Twine::utohexstr(Sec.Addr) +
|
|
" cannot be increased by 0x" +
|
|
Twine::utohexstr(PatternUpdate.Update.Value) +
|
|
". The result would overflow");
|
|
}
|
|
|
|
switch (PatternUpdate.Update.Kind) {
|
|
case (AdjustKind::Set):
|
|
Sec.Addr = PatternUpdate.Update.Value;
|
|
break;
|
|
case (AdjustKind::Subtract):
|
|
Sec.Addr -= PatternUpdate.Update.Value;
|
|
break;
|
|
case (AdjustKind::Add):
|
|
Sec.Addr += PatternUpdate.Update.Value;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (Config.OnlyKeepDebug)
|
|
for (auto &Sec : Obj.sections())
|
|
if (Sec.Flags & SHF_ALLOC && Sec.Type != SHT_NOTE)
|
|
Sec.Type = SHT_NOBITS;
|
|
|
|
endianness E = OutputElfType == ELFT_ELF32LE || OutputElfType == ELFT_ELF64LE
|
|
? endianness::little
|
|
: endianness::big;
|
|
|
|
for (const NewSectionInfo &AddedSection : Config.AddSection) {
|
|
auto AddSection = [&](StringRef Name, ArrayRef<uint8_t> Data) -> Error {
|
|
OwnedDataSection &NewSection =
|
|
Obj.addSection<OwnedDataSection>(Name, Data);
|
|
if (Name.starts_with(".note") && Name != ".note.GNU-stack") {
|
|
NewSection.Type = SHT_NOTE;
|
|
if (ELFConfig.VerifyNoteSections)
|
|
return verifyNoteSection(Name, E, Data);
|
|
}
|
|
return Error::success();
|
|
};
|
|
if (Error E = handleUserSection(AddedSection, AddSection))
|
|
return E;
|
|
}
|
|
|
|
for (const NewSectionInfo &NewSection : Config.UpdateSection) {
|
|
auto UpdateSection = [&](StringRef Name, ArrayRef<uint8_t> Data) {
|
|
return Obj.updateSection(Name, Data);
|
|
};
|
|
if (Error E = handleUserSection(NewSection, UpdateSection))
|
|
return E;
|
|
}
|
|
|
|
if (!Config.AddGnuDebugLink.empty())
|
|
Obj.addSection<GnuDebugLinkSection>(Config.AddGnuDebugLink,
|
|
Config.GnuDebugLinkCRC32);
|
|
|
|
// If the symbol table was previously removed, we need to create a new one
|
|
// before adding new symbols.
|
|
if (!Obj.SymbolTable && !Config.SymbolsToAdd.empty())
|
|
if (Error E = Obj.addNewSymbolTable())
|
|
return E;
|
|
|
|
for (const NewSymbolInfo &SI : Config.SymbolsToAdd)
|
|
addSymbol(Obj, SI, ELFConfig.NewSymbolVisibility);
|
|
|
|
// --set-section-{flags,type} work with sections added by --add-section.
|
|
if (!Config.SetSectionFlags.empty() || !Config.SetSectionType.empty()) {
|
|
for (auto &Sec : Obj.sections()) {
|
|
const auto Iter = Config.SetSectionFlags.find(Sec.Name);
|
|
if (Iter != Config.SetSectionFlags.end()) {
|
|
const SectionFlagsUpdate &SFU = Iter->second;
|
|
if (Error E = setSectionFlagsAndType(Sec, SFU.NewFlags, Obj.Machine))
|
|
return E;
|
|
}
|
|
auto It2 = Config.SetSectionType.find(Sec.Name);
|
|
if (It2 != Config.SetSectionType.end())
|
|
setSectionType(Sec, It2->second);
|
|
}
|
|
}
|
|
|
|
if (!Config.SectionsToRename.empty()) {
|
|
std::vector<RelocationSectionBase *> RelocSections;
|
|
DenseSet<SectionBase *> RenamedSections;
|
|
for (SectionBase &Sec : Obj.sections()) {
|
|
auto *RelocSec = dyn_cast<RelocationSectionBase>(&Sec);
|
|
const auto Iter = Config.SectionsToRename.find(Sec.Name);
|
|
if (Iter != Config.SectionsToRename.end()) {
|
|
const SectionRename &SR = Iter->second;
|
|
Sec.Name = std::string(SR.NewName);
|
|
if (SR.NewFlags) {
|
|
if (Error E = setSectionFlagsAndType(Sec, *SR.NewFlags, Obj.Machine))
|
|
return E;
|
|
}
|
|
RenamedSections.insert(&Sec);
|
|
} else if (RelocSec && !(Sec.Flags & SHF_ALLOC))
|
|
// Postpone processing relocation sections which are not specified in
|
|
// their explicit '--rename-section' commands until after their target
|
|
// sections are renamed.
|
|
// Dynamic relocation sections (i.e. ones with SHF_ALLOC) should be
|
|
// renamed only explicitly. Otherwise, renaming, for example, '.got.plt'
|
|
// would affect '.rela.plt', which is not desirable.
|
|
RelocSections.push_back(RelocSec);
|
|
}
|
|
|
|
// Rename relocation sections according to their target sections.
|
|
for (RelocationSectionBase *RelocSec : RelocSections) {
|
|
auto Iter = RenamedSections.find(RelocSec->getSection());
|
|
if (Iter != RenamedSections.end())
|
|
RelocSec->Name = (RelocSec->getNamePrefix() + (*Iter)->Name).str();
|
|
}
|
|
}
|
|
|
|
// Add a prefix to allocated sections and their relocation sections. This
|
|
// should be done after renaming the section by Config.SectionToRename to
|
|
// imitate the GNU objcopy behavior.
|
|
if (!Config.AllocSectionsPrefix.empty()) {
|
|
DenseSet<SectionBase *> PrefixedSections;
|
|
for (SectionBase &Sec : Obj.sections()) {
|
|
if (Sec.Flags & SHF_ALLOC) {
|
|
Sec.Name = (Config.AllocSectionsPrefix + Sec.Name).str();
|
|
PrefixedSections.insert(&Sec);
|
|
} else if (auto *RelocSec = dyn_cast<RelocationSectionBase>(&Sec)) {
|
|
// Rename relocation sections associated to the allocated sections.
|
|
// For example, if we rename .text to .prefix.text, we also rename
|
|
// .rel.text to .rel.prefix.text.
|
|
//
|
|
// Dynamic relocation sections (SHT_REL[A] with SHF_ALLOC) are handled
|
|
// above, e.g., .rela.plt is renamed to .prefix.rela.plt, not
|
|
// .rela.prefix.plt since GNU objcopy does so.
|
|
const SectionBase *TargetSec = RelocSec->getSection();
|
|
if (TargetSec && (TargetSec->Flags & SHF_ALLOC)) {
|
|
// If the relocation section comes *after* the target section, we
|
|
// don't add Config.AllocSectionsPrefix because we've already added
|
|
// the prefix to TargetSec->Name. Otherwise, if the relocation
|
|
// section comes *before* the target section, we add the prefix.
|
|
if (PrefixedSections.count(TargetSec))
|
|
Sec.Name = (RelocSec->getNamePrefix() + TargetSec->Name).str();
|
|
else
|
|
Sec.Name = (RelocSec->getNamePrefix() + Config.AllocSectionsPrefix +
|
|
TargetSec->Name)
|
|
.str();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (ELFConfig.EntryExpr)
|
|
Obj.Entry = ELFConfig.EntryExpr(Obj.Entry);
|
|
return Error::success();
|
|
}
|
|
|
|
static Error writeOutput(const CommonConfig &Config, Object &Obj,
|
|
raw_ostream &Out, ElfType OutputElfType) {
|
|
std::unique_ptr<Writer> Writer =
|
|
createWriter(Config, Obj, Out, OutputElfType);
|
|
if (Error E = Writer->finalize())
|
|
return E;
|
|
return Writer->write();
|
|
}
|
|
|
|
Error objcopy::elf::executeObjcopyOnIHex(const CommonConfig &Config,
|
|
const ELFConfig &ELFConfig,
|
|
MemoryBuffer &In, raw_ostream &Out) {
|
|
IHexReader Reader(&In);
|
|
Expected<std::unique_ptr<Object>> Obj = Reader.create(true);
|
|
if (!Obj)
|
|
return Obj.takeError();
|
|
|
|
const ElfType OutputElfType =
|
|
getOutputElfType(Config.OutputArch.value_or(MachineInfo()));
|
|
if (Error E = handleArgs(Config, ELFConfig, OutputElfType, **Obj))
|
|
return E;
|
|
return writeOutput(Config, **Obj, Out, OutputElfType);
|
|
}
|
|
|
|
Error objcopy::elf::executeObjcopyOnRawBinary(const CommonConfig &Config,
|
|
const ELFConfig &ELFConfig,
|
|
MemoryBuffer &In,
|
|
raw_ostream &Out) {
|
|
BinaryReader Reader(&In, ELFConfig.NewSymbolVisibility);
|
|
Expected<std::unique_ptr<Object>> Obj = Reader.create(true);
|
|
if (!Obj)
|
|
return Obj.takeError();
|
|
|
|
// Prefer OutputArch (-O<format>) if set, otherwise fallback to BinaryArch
|
|
// (-B<arch>).
|
|
const ElfType OutputElfType =
|
|
getOutputElfType(Config.OutputArch.value_or(MachineInfo()));
|
|
if (Error E = handleArgs(Config, ELFConfig, OutputElfType, **Obj))
|
|
return E;
|
|
return writeOutput(Config, **Obj, Out, OutputElfType);
|
|
}
|
|
|
|
Error objcopy::elf::executeObjcopyOnBinary(const CommonConfig &Config,
|
|
const ELFConfig &ELFConfig,
|
|
object::ELFObjectFileBase &In,
|
|
raw_ostream &Out) {
|
|
ELFReader Reader(&In, Config.ExtractPartition);
|
|
Expected<std::unique_ptr<Object>> Obj =
|
|
Reader.create(!Config.SymbolsToAdd.empty());
|
|
if (!Obj)
|
|
return Obj.takeError();
|
|
// Prefer OutputArch (-O<format>) if set, otherwise infer it from the input.
|
|
const ElfType OutputElfType = Config.OutputArch
|
|
? getOutputElfType(*Config.OutputArch)
|
|
: getOutputElfType(In);
|
|
|
|
if (Error E = handleArgs(Config, ELFConfig, OutputElfType, **Obj))
|
|
return createFileError(Config.InputFilename, std::move(E));
|
|
|
|
if (Error E = writeOutput(Config, **Obj, Out, OutputElfType))
|
|
return createFileError(Config.InputFilename, std::move(E));
|
|
|
|
return Error::success();
|
|
}
|