text: //===- Archive.cpp - ar File Format implementation --------------*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file defines the ArchiveObjectFile class.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/Object/Archive.h"
  #include "llvm/ADT/APInt.h"
  #include "llvm/ADT/SmallString.h"
  #include "llvm/ADT/Twine.h"
  #include "llvm/Support/Endian.h"
  #include "llvm/Support/MemoryBuffer.h"
  #include "llvm/Support/Path.h"
  
  using namespace llvm;
  using namespace object;
  using namespace llvm::support::endian;
  
  static const char *const Magic = "!<arch>\n";
  static const char *const ThinMagic = "!<thin>\n";
  
  void Archive::anchor() { }
  
  StringRef ArchiveMemberHeader::getName() const {
    char EndCond;
    if (Name[0] == '/' || Name[0] == '#')
      EndCond = ' ';
    else
      EndCond = '/';
    llvm::StringRef::size_type end =
        llvm::StringRef(Name, sizeof(Name)).find(EndCond);
    if (end == llvm::StringRef::npos)
      end = sizeof(Name);
    assert(end <= sizeof(Name) && end > 0);
    // Don't include the EndCond if there is one.
    return llvm::StringRef(Name, end);
  }
  
  uint32_t ArchiveMemberHeader::getSize() const {
    uint32_t Ret;
    if (llvm::StringRef(Size, sizeof(Size)).rtrim(" ").getAsInteger(10, Ret))
      llvm_unreachable("Size is not a decimal number.");
    return Ret;
  }
  
  sys::fs::perms ArchiveMemberHeader::getAccessMode() const {
    unsigned Ret;
    if (StringRef(AccessMode, sizeof(AccessMode)).rtrim(" ").getAsInteger(8, Ret))
      llvm_unreachable("Access mode is not an octal number.");
    return static_cast<sys::fs::perms>(Ret);
  }
  
  sys::TimeValue ArchiveMemberHeader::getLastModified() const {
    unsigned Seconds;
    if (StringRef(LastModified, sizeof(LastModified)).rtrim(" ")
            .getAsInteger(10, Seconds))
      llvm_unreachable("Last modified time not a decimal number.");
  
    sys::TimeValue Ret;
    Ret.fromEpochTime(Seconds);
    return Ret;
  }
  
  unsigned ArchiveMemberHeader::getUID() const {
    unsigned Ret;
    if (StringRef(UID, sizeof(UID)).rtrim(" ").getAsInteger(10, Ret))
      llvm_unreachable("UID time not a decimal number.");
    return Ret;
  }
  
  unsigned ArchiveMemberHeader::getGID() const {
    unsigned Ret;
    if (StringRef(GID, sizeof(GID)).rtrim(" ").getAsInteger(10, Ret))
      llvm_unreachable("GID time not a decimal number.");
    return Ret;
  }
  
  Archive::Child::Child(const Archive *Parent, const char *Start)
      : Parent(Parent) {
    if (!Start)
      return;
  
    const ArchiveMemberHeader *Header =
        reinterpret_cast<const ArchiveMemberHeader *>(Start);
    uint64_t Size = sizeof(ArchiveMemberHeader);
    if (!Parent->IsThin || Header->getName() == "/" || Header->getName() == "//")
      Size += Header->getSize();
    Data = StringRef(Start, Size);
  
    // Setup StartOfFile and PaddingBytes.
    StartOfFile = sizeof(ArchiveMemberHeader);
    // Don't include attached name.
    StringRef Name = Header->getName();
    if (Name.startswith("#1/")) {
      uint64_t NameSize;
      if (Name.substr(3).rtrim(" ").getAsInteger(10, NameSize))
        llvm_unreachable("Long name length is not an integer");
      StartOfFile += NameSize;
    }
  }
  
  uint64_t Archive::Child::getSize() const {
    if (Parent->IsThin)
      return getHeader()->getSize();
    return Data.size() - StartOfFile;
  }
  
  uint64_t Archive::Child::getRawSize() const {
    return getHeader()->getSize();
  }
  
  ErrorOr<StringRef> Archive::Child::getBuffer() const {
    if (!Parent->IsThin)
      return StringRef(Data.data() + StartOfFile, getSize());
    ErrorOr<StringRef> Name = getName();
    if (std::error_code EC = Name.getError())
      return EC;
    SmallString<128> FullName =
        Parent->getMemoryBufferRef().getBufferIdentifier();
    sys::path::remove_filename(FullName);
    sys::path::append(FullName, *Name);
    ErrorOr<std::unique_ptr<MemoryBuffer>> Buf = MemoryBuffer::getFile(FullName);
    if (std::error_code EC = Buf.getError())
      return EC;
    Parent->ThinBuffers.push_back(std::move(*Buf));
    return Parent->ThinBuffers.back()->getBuffer();
  }
  
  Archive::Child Archive::Child::getNext() const {
    size_t SpaceToSkip = Data.size();
    // If it's odd, add 1 to make it even.
    if (SpaceToSkip & 1)
      ++SpaceToSkip;
  
    const char *NextLoc = Data.data() + SpaceToSkip;
  
    // Check to see if this is past the end of the archive.
    if (NextLoc >= Parent->Data.getBufferEnd())
      return Child(Parent, nullptr);
  
    return Child(Parent, NextLoc);
  }
  
  uint64_t Archive::Child::getChildOffset() const {
    const char *a = Parent->Data.getBuffer().data();
    const char *c = Data.data();
    uint64_t offset = c - a;
    return offset;
  }
  
  ErrorOr<StringRef> Archive::Child::getName() const {
    StringRef name = getRawName();
    // Check if it's a special name.
    if (name[0] == '/') {
      if (name.size() == 1) // Linker member.
        return name;
      if (name.size() == 2 && name[1] == '/') // String table.
        return name;
      // It's a long name.
      // Get the offset.
      std::size_t offset;
      if (name.substr(1).rtrim(" ").getAsInteger(10, offset))
        llvm_unreachable("Long name offset is not an integer");
      const char *addr = Parent->StringTable->Data.begin()
                         + sizeof(ArchiveMemberHeader)
                         + offset;
      // Verify it.
      if (Parent->StringTable == Parent->child_end()
          || addr < (Parent->StringTable->Data.begin()
                     + sizeof(ArchiveMemberHeader))
          || addr > (Parent->StringTable->Data.begin()
                     + sizeof(ArchiveMemberHeader)
                     + Parent->StringTable->getSize()))
        return object_error::parse_failed;
  
      // GNU long file names end with a "/\n".
      if (Parent->kind() == K_GNU || Parent->kind() == K_MIPS64) {
        StringRef::size_type End = StringRef(addr).find('\n');
        return StringRef(addr, End - 1);
      }
      return StringRef(addr);
    } else if (name.startswith("#1/")) {
      uint64_t name_size;
      if (name.substr(3).rtrim(" ").getAsInteger(10, name_size))
        llvm_unreachable("Long name length is not an ingeter");
      return Data.substr(sizeof(ArchiveMemberHeader), name_size)
          .rtrim(StringRef("\0", 1));
    }
    // It's a simple name.
    if (name[name.size() - 1] == '/')
      return name.substr(0, name.size() - 1);
    return name;
  }
  
  ErrorOr<MemoryBufferRef> Archive::Child::getMemoryBufferRef() const {
    ErrorOr<StringRef> NameOrErr = getName();
    if (std::error_code EC = NameOrErr.getError())
      return EC;
    StringRef Name = NameOrErr.get();
    ErrorOr<StringRef> Buf = getBuffer();
    if (std::error_code EC = Buf.getError())
      return EC;
    return MemoryBufferRef(*Buf, Name);
  }
  
  ErrorOr<std::unique_ptr<Binary>>
  Archive::Child::getAsBinary(LLVMContext *Context) const {
    ErrorOr<MemoryBufferRef> BuffOrErr = getMemoryBufferRef();
    if (std::error_code EC = BuffOrErr.getError())
      return EC;
  
    return createBinary(BuffOrErr.get(), Context);
  }
  
  ErrorOr<std::unique_ptr<Archive>> Archive::create(MemoryBufferRef Source) {
    std::error_code EC;
    std::unique_ptr<Archive> Ret(new Archive(Source, EC));
    if (EC)
      return EC;
    return std::move(Ret);
  }
  
  Archive::Archive(MemoryBufferRef Source, std::error_code &ec)
      : Binary(Binary::ID_Archive, Source), SymbolTable(child_end()),
        StringTable(child_end()), FirstRegular(child_end()) {
    StringRef Buffer = Data.getBuffer();
    // Check for sufficient magic.
    if (Buffer.startswith(ThinMagic)) {
      IsThin = true;
    } else if (Buffer.startswith(Magic)) {
      IsThin = false;
    } else {
      ec = object_error::invalid_file_type;
      return;
    }
  
    // Get the special members.
    child_iterator i = child_begin(false);
    child_iterator e = child_end();
  
    if (i == e) {
      ec = std::error_code();
      return;
    }
  
    StringRef Name = i->getRawName();
  
    // Below is the pattern that is used to figure out the archive format
    // GNU archive format
    //  First member : / (may exist, if it exists, points to the symbol table )
    //  Second member : // (may exist, if it exists, points to the string table)
    //  Note : The string table is used if the filename exceeds 15 characters
    // BSD archive format
    //  First member : __.SYMDEF or "__.SYMDEF SORTED" (the symbol table)
    //  There is no string table, if the filename exceeds 15 characters or has a
    //  embedded space, the filename has #1/<size>, The size represents the size
    //  of the filename that needs to be read after the archive header
    // COFF archive format
    //  First member : /
    //  Second member : / (provides a directory of symbols)
    //  Third member : // (may exist, if it exists, contains the string table)
    //  Note: Microsoft PE/COFF Spec 8.3 says that the third member is present
    //  even if the string table is empty. However, lib.exe does not in fact
    //  seem to create the third member if there's no member whose filename
    //  exceeds 15 characters. So the third member is optional.
  
    if (Name == "__.SYMDEF") {
      Format = K_BSD;
      SymbolTable = i;
      ++i;
      FirstRegular = i;
      ec = std::error_code();
      return;
    }
  
    if (Name.startswith("#1/")) {
      Format = K_BSD;
      // We know this is BSD, so getName will work since there is no string table.
      ErrorOr<StringRef> NameOrErr = i->getName();
      ec = NameOrErr.getError();
      if (ec)
        return;
      Name = NameOrErr.get();
      if (Name == "__.SYMDEF SORTED" || Name == "__.SYMDEF") {
        SymbolTable = i;
        ++i;
      }
      FirstRegular = i;
      return;
    }
  
    // MIPS 64-bit ELF archives use a special format of a symbol table.
    // This format is marked by `ar_name` field equals to "/SYM64/".
    // For detailed description see page 96 in the following document:
    // http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf
  
    bool has64SymTable = false;
    if (Name == "/" || Name == "/SYM64/") {
      SymbolTable = i;
      if (Name == "/SYM64/")
        has64SymTable = true;
  
      ++i;
      if (i == e) {
        ec = std::error_code();
        return;
      }
      Name = i->getRawName();
    }
  
    if (Name == "//") {
      Format = has64SymTable ? K_MIPS64 : K_GNU;
      StringTable = i;
      ++i;
      FirstRegular = i;
      ec = std::error_code();
      return;
    }
  
    if (Name[0] != '/') {
      Format = has64SymTable ? K_MIPS64 : K_GNU;
      FirstRegular = i;
      ec = std::error_code();
      return;
    }
  
    if (Name != "/") {
      ec = object_error::parse_failed;
      return;
    }
  
    Format = K_COFF;
    SymbolTable = i;
  
    ++i;
    if (i == e) {
      FirstRegular = i;
      ec = std::error_code();
      return;
    }
  
    Name = i->getRawName();
  
    if (Name == "//") {
      StringTable = i;
      ++i;
    }
  
    FirstRegular = i;
    ec = std::error_code();
  }
  
  Archive::child_iterator Archive::child_begin(bool SkipInternal) const {
    if (Data.getBufferSize() == 8) // empty archive.
      return child_end();
  
    if (SkipInternal)
      return FirstRegular;
  
    const char *Loc = Data.getBufferStart() + strlen(Magic);
    Child c(this, Loc);
    return c;
  }
  
  Archive::child_iterator Archive::child_end() const {
    return Child(this, nullptr);
  }
  
  StringRef Archive::Symbol::getName() const {
    return Parent->getSymbolTable().begin() + StringIndex;
  }
  
  ErrorOr<Archive::child_iterator> Archive::Symbol::getMember() const {
    const char *Buf = Parent->getSymbolTable().begin();
    const char *Offsets = Buf;
    if (Parent->kind() == K_MIPS64)
      Offsets += sizeof(uint64_t);
    else
      Offsets += sizeof(uint32_t);
    uint32_t Offset = 0;
    if (Parent->kind() == K_GNU) {
      Offset = read32be(Offsets + SymbolIndex * 4);
    } else if (Parent->kind() == K_MIPS64) {
      Offset = read64be(Offsets + SymbolIndex * 8);
    } else if (Parent->kind() == K_BSD) {
      // The SymbolIndex is an index into the ranlib structs that start at
      // Offsets (the first uint32_t is the number of bytes of the ranlib
      // structs).  The ranlib structs are a pair of uint32_t's the first
      // being a string table offset and the second being the offset into
      // the archive of the member that defines the symbol.  Which is what
      // is needed here.
      Offset = read32le(Offsets + SymbolIndex * 8 + 4);
    } else {
      // Skip offsets.
      uint32_t MemberCount = read32le(Buf);
      Buf += MemberCount * 4 + 4;
  
      uint32_t SymbolCount = read32le(Buf);
      if (SymbolIndex >= SymbolCount)
        return object_error::parse_failed;
  
      // Skip SymbolCount to get to the indices table.
      const char *Indices = Buf + 4;
  
      // Get the index of the offset in the file member offset table for this
      // symbol.
      uint16_t OffsetIndex = read16le(Indices + SymbolIndex * 2);
      // Subtract 1 since OffsetIndex is 1 based.
      --OffsetIndex;
  
      if (OffsetIndex >= MemberCount)
        return object_error::parse_failed;
  
      Offset = read32le(Offsets + OffsetIndex * 4);
    }
  
    const char *Loc = Parent->getData().begin() + Offset;
    child_iterator Iter(Child(Parent, Loc));
    return Iter;
  }
  
  Archive::Symbol Archive::Symbol::getNext() const {
    Symbol t(*this);
    if (Parent->kind() == K_BSD) {
      // t.StringIndex is an offset from the start of the __.SYMDEF or
      // "__.SYMDEF SORTED" member into the string table for the ranlib
      // struct indexed by t.SymbolIndex .  To change t.StringIndex to the
      // offset in the string table for t.SymbolIndex+1 we subtract the
      // its offset from the start of the string table for t.SymbolIndex
      // and add the offset of the string table for t.SymbolIndex+1.
  
      // The __.SYMDEF or "__.SYMDEF SORTED" member starts with a uint32_t
      // which is the number of bytes of ranlib structs that follow.  The ranlib
      // structs are a pair of uint32_t's the first being a string table offset
      // and the second being the offset into the archive of the member that
      // define the symbol. After that the next uint32_t is the byte count of
      // the string table followed by the string table.
      const char *Buf = Parent->getSymbolTable().begin();
      uint32_t RanlibCount = 0;
      RanlibCount = read32le(Buf) / 8;
      // If t.SymbolIndex + 1 will be past the count of symbols (the RanlibCount)
      // don't change the t.StringIndex as we don't want to reference a ranlib
      // past RanlibCount.
      if (t.SymbolIndex + 1 < RanlibCount) {
        const char *Ranlibs = Buf + 4;
        uint32_t CurRanStrx = 0;
        uint32_t NextRanStrx = 0;
        CurRanStrx = read32le(Ranlibs + t.SymbolIndex * 8);
        NextRanStrx = read32le(Ranlibs + (t.SymbolIndex + 1) * 8);
        t.StringIndex -= CurRanStrx;
        t.StringIndex += NextRanStrx;
      }
    } else {
      // Go to one past next null.
      t.StringIndex = Parent->getSymbolTable().find('\0', t.StringIndex) + 1;
    }
    ++t.SymbolIndex;
    return t;
  }
  
  Archive::symbol_iterator Archive::symbol_begin() const {
    if (!hasSymbolTable())
      return symbol_iterator(Symbol(this, 0, 0));
  
    const char *buf = getSymbolTable().begin();
    if (kind() == K_GNU) {
      uint32_t symbol_count = 0;
      symbol_count = read32be(buf);
      buf += sizeof(uint32_t) + (symbol_count * (sizeof(uint32_t)));
    } else if (kind() == K_MIPS64) {
      uint64_t symbol_count = read64be(buf);
      buf += sizeof(uint64_t) + (symbol_count * (sizeof(uint64_t)));
    } else if (kind() == K_BSD) {
      // The __.SYMDEF or "__.SYMDEF SORTED" member starts with a uint32_t
      // which is the number of bytes of ranlib structs that follow.  The ranlib
      // structs are a pair of uint32_t's the first being a string table offset
      // and the second being the offset into the archive of the member that
      // define the symbol. After that the next uint32_t is the byte count of
      // the string table followed by the string table.
      uint32_t ranlib_count = 0;
      ranlib_count = read32le(buf) / 8;
      const char *ranlibs = buf + 4;
      uint32_t ran_strx = 0;
      ran_strx = read32le(ranlibs);
      buf += sizeof(uint32_t) + (ranlib_count * (2 * (sizeof(uint32_t))));
      // Skip the byte count of the string table.
      buf += sizeof(uint32_t);
      buf += ran_strx;
    } else {
      uint32_t member_count = 0;
      uint32_t symbol_count = 0;
      member_count = read32le(buf);
      buf += 4 + (member_count * 4); // Skip offsets.
      symbol_count = read32le(buf);
      buf += 4 + (symbol_count * 2); // Skip indices.
    }
    uint32_t string_start_offset = buf - getSymbolTable().begin();
    return symbol_iterator(Symbol(this, 0, string_start_offset));
  }
  
  Archive::symbol_iterator Archive::symbol_end() const {
    if (!hasSymbolTable())
      return symbol_iterator(Symbol(this, 0, 0));
    return symbol_iterator(Symbol(this, getNumberOfSymbols(), 0));
  }
  
  uint32_t Archive::getNumberOfSymbols() const {
    const char *buf = getSymbolTable().begin();
    if (kind() == K_GNU)
      return read32be(buf);
    if (kind() == K_MIPS64)
      return read64be(buf);
    if (kind() == K_BSD)
      return read32le(buf) / 8;
    uint32_t member_count = 0;
    member_count = read32le(buf);
    buf += 4 + (member_count * 4); // Skip offsets.
    return read32le(buf);
  }
  
  Archive::child_iterator Archive::findSym(StringRef name) const {
    Archive::symbol_iterator bs = symbol_begin();
    Archive::symbol_iterator es = symbol_end();
  
    for (; bs != es; ++bs) {
      StringRef SymName = bs->getName();
      if (SymName == name) {
        ErrorOr<Archive::child_iterator> ResultOrErr = bs->getMember();
        // FIXME: Should we really eat the error?
        if (ResultOrErr.getError())
          return child_end();
        return ResultOrErr.get();
      }
    }
    return child_end();
  }
  
  bool Archive::hasSymbolTable() const {
    return SymbolTable != child_end();
  }
  