text: //===- llvm-objcopy.cpp ---------------------------------------------------===//
  //
  // 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 "llvm-objcopy.h"
  #include "Buffer.h"
  #include "COFF/COFFObjcopy.h"
  #include "CopyConfig.h"
  #include "ELF/ELFObjcopy.h"
  
  #include "llvm/ADT/STLExtras.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/ADT/StringRef.h"
  #include "llvm/ADT/Twine.h"
  #include "llvm/Object/Archive.h"
  #include "llvm/Object/ArchiveWriter.h"
  #include "llvm/Object/Binary.h"
  #include "llvm/Object/COFF.h"
  #include "llvm/Object/ELFObjectFile.h"
  #include "llvm/Object/ELFTypes.h"
  #include "llvm/Object/Error.h"
  #include "llvm/Option/Arg.h"
  #include "llvm/Option/ArgList.h"
  #include "llvm/Option/Option.h"
  #include "llvm/Support/Casting.h"
  #include "llvm/Support/Error.h"
  #include "llvm/Support/ErrorHandling.h"
  #include "llvm/Support/ErrorOr.h"
  #include "llvm/Support/InitLLVM.h"
  #include "llvm/Support/Memory.h"
  #include "llvm/Support/Path.h"
  #include "llvm/Support/Process.h"
  #include "llvm/Support/WithColor.h"
  #include "llvm/Support/raw_ostream.h"
  #include <algorithm>
  #include <cassert>
  #include <cstdlib>
  #include <memory>
  #include <string>
  #include <system_error>
  #include <utility>
  
  namespace llvm {
  namespace objcopy {
  
  // The name this program was invoked as.
  StringRef ToolName;
  
  LLVM_ATTRIBUTE_NORETURN void error(Twine Message) {
    WithColor::error(errs(), ToolName) << Message << ".\n";
    errs().flush();
    exit(1);
  }
  
  LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, std::error_code EC) {
    assert(EC);
    WithColor::error(errs(), ToolName)
        << "'" << File << "': " << EC.message() << ".\n";
    exit(1);
  }
  
  LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, Error E) {
    assert(E);
    std::string Buf;
    raw_string_ostream OS(Buf);
    logAllUnhandledErrors(std::move(E), OS);
    OS.flush();
    WithColor::error(errs(), ToolName) << "'" << File << "': " << Buf;
    exit(1);
  }
  
  } // end namespace objcopy
  } // end namespace llvm
  
  using namespace llvm;
  using namespace llvm::object;
  using namespace llvm::objcopy;
  
  // For regular archives this function simply calls llvm::writeArchive,
  // For thin archives it writes the archive file itself as well as its members.
  static Error deepWriteArchive(StringRef ArcName,
                                ArrayRef<NewArchiveMember> NewMembers,
                                bool WriteSymtab, object::Archive::Kind Kind,
                                bool Deterministic, bool Thin) {
    Error E =
        writeArchive(ArcName, NewMembers, WriteSymtab, Kind, Deterministic, Thin);
    if (!Thin || E)
      return E;
    for (const NewArchiveMember &Member : NewMembers) {
      // Internally, FileBuffer will use the buffer created by
      // FileOutputBuffer::create, for regular files (that is the case for
      // deepWriteArchive) FileOutputBuffer::create will return OnDiskBuffer.
      // OnDiskBuffer uses a temporary file and then renames it. So in reality
      // there is no inefficiency / duplicated in-memory buffers in this case. For
      // now in-memory buffers can not be completely avoided since
      // NewArchiveMember still requires them even though writeArchive does not
      // write them on disk.
      FileBuffer FB(Member.MemberName);
      FB.allocate(Member.Buf->getBufferSize());
      std::copy(Member.Buf->getBufferStart(), Member.Buf->getBufferEnd(),
                FB.getBufferStart());
      if (auto E = FB.commit())
        return E;
    }
    return Error::success();
  }
  
  /// The function executeObjcopyOnRawBinary does the dispatch based on the format
  /// of the output specified by the command line options.
  static void executeObjcopyOnRawBinary(const CopyConfig &Config,
                                        MemoryBuffer &In, Buffer &Out) {
    // TODO: llvm-objcopy should parse CopyConfig.OutputFormat to recognize
    // formats other than ELF / "binary" and invoke
    // elf::executeObjcopyOnRawBinary, macho::executeObjcopyOnRawBinary or
    // coff::executeObjcopyOnRawBinary accordingly.
    return elf::executeObjcopyOnRawBinary(Config, In, Out);
  }
  
  /// The function executeObjcopyOnBinary does the dispatch based on the format
  /// of the input binary (ELF, MachO or COFF).
  static void executeObjcopyOnBinary(const CopyConfig &Config, object::Binary &In,
                                     Buffer &Out) {
    if (auto *ELFBinary = dyn_cast<object::ELFObjectFileBase>(&In))
      return elf::executeObjcopyOnBinary(Config, *ELFBinary, Out);
    else if (auto *COFFBinary = dyn_cast<object::COFFObjectFile>(&In))
      return coff::executeObjcopyOnBinary(Config, *COFFBinary, Out);
    else
      error("Unsupported object file format");
  }
  
  static void executeObjcopyOnArchive(const CopyConfig &Config,
                                      const Archive &Ar) {
    std::vector<NewArchiveMember> NewArchiveMembers;
    Error Err = Error::success();
    for (const Archive::Child &Child : Ar.children(Err)) {
      Expected<std::unique_ptr<Binary>> ChildOrErr = Child.getAsBinary();
      if (!ChildOrErr)
        reportError(Ar.getFileName(), ChildOrErr.takeError());
      Binary *Bin = ChildOrErr->get();
  
      Expected<StringRef> ChildNameOrErr = Child.getName();
      if (!ChildNameOrErr)
        reportError(Ar.getFileName(), ChildNameOrErr.takeError());
  
      MemBuffer MB(ChildNameOrErr.get());
      executeObjcopyOnBinary(Config, *Bin, MB);
  
      Expected<NewArchiveMember> Member =
          NewArchiveMember::getOldMember(Child, Config.DeterministicArchives);
      if (!Member)
        reportError(Ar.getFileName(), Member.takeError());
      Member->Buf = MB.releaseMemoryBuffer();
      Member->MemberName = Member->Buf->getBufferIdentifier();
      NewArchiveMembers.push_back(std::move(*Member));
    }
  
    if (Err)
      reportError(Config.InputFilename, std::move(Err));
    if (Error E = deepWriteArchive(Config.OutputFilename, NewArchiveMembers,
                                   Ar.hasSymbolTable(), Ar.kind(),
                                   Config.DeterministicArchives, Ar.isThin()))
      reportError(Config.OutputFilename, std::move(E));
  }
  
  static void restoreDateOnFile(StringRef Filename,
                                const sys::fs::file_status &Stat) {
    int FD;
  
    if (auto EC =
            sys::fs::openFileForWrite(Filename, FD, sys::fs::CD_OpenExisting))
      reportError(Filename, EC);
  
    if (auto EC = sys::fs::setLastAccessAndModificationTime(
            FD, Stat.getLastAccessedTime(), Stat.getLastModificationTime()))
      reportError(Filename, EC);
  
    if (auto EC = sys::Process::SafelyCloseFileDescriptor(FD))
      reportError(Filename, EC);
  }
  
  /// The function executeObjcopy does the higher level dispatch based on the type
  /// of input (raw binary, archive or single object file) and takes care of the
  /// format-agnostic modifications, i.e. preserving dates.
  static void executeObjcopy(const CopyConfig &Config) {
    sys::fs::file_status Stat;
    if (Config.PreserveDates)
      if (auto EC = sys::fs::status(Config.InputFilename, Stat))
        reportError(Config.InputFilename, EC);
  
    if (Config.InputFormat == "binary") {
      auto BufOrErr = MemoryBuffer::getFile(Config.InputFilename);
      if (!BufOrErr)
        reportError(Config.InputFilename, BufOrErr.getError());
      FileBuffer FB(Config.OutputFilename);
      executeObjcopyOnRawBinary(Config, *BufOrErr->get(), FB);
    } else {
      Expected<OwningBinary<llvm::object::Binary>> BinaryOrErr =
          createBinary(Config.InputFilename);
      if (!BinaryOrErr)
        reportError(Config.InputFilename, BinaryOrErr.takeError());
  
      if (Archive *Ar = dyn_cast<Archive>(BinaryOrErr.get().getBinary())) {
        executeObjcopyOnArchive(Config, *Ar);
      } else {
        FileBuffer FB(Config.OutputFilename);
        executeObjcopyOnBinary(Config, *BinaryOrErr.get().getBinary(), FB);
      }
    }
  
    if (Config.PreserveDates) {
      restoreDateOnFile(Config.OutputFilename, Stat);
      if (!Config.SplitDWO.empty())
        restoreDateOnFile(Config.SplitDWO, Stat);
    }
  }
  
  int main(int argc, char **argv) {
    InitLLVM X(argc, argv);
    ToolName = argv[0];
    DriverConfig DriverConfig;
    if (sys::path::stem(ToolName).contains("strip"))
      DriverConfig = parseStripOptions(makeArrayRef(argv + 1, argc));
    else
      DriverConfig = parseObjcopyOptions(makeArrayRef(argv + 1, argc));
    for (const CopyConfig &CopyConfig : DriverConfig.CopyConfigs)
      executeObjcopy(CopyConfig);
  }
  