lib/Object/ArchiveWriter.cpp

   1 //===- ArchiveWriter.cpp - ar File Format implementation --------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file defines the writeArchive function.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Object/ArchiveWriter.h"
  15 #include "llvm/ADT/ArrayRef.h"
  16 #include "llvm/ADT/StringRef.h"
  17 #include "llvm/IR/LLVMContext.h"
  18 #include "llvm/Object/Archive.h"
  19 #include "llvm/Object/ObjectFile.h"
  20 #include "llvm/Object/SymbolicFile.h"
  21 #include "llvm/Support/EndianStream.h"
  22 #include "llvm/Support/Errc.h"
  23 #include "llvm/Support/ErrorHandling.h"
  24 #include "llvm/Support/Format.h"
  25 #include "llvm/Support/Path.h"
  26 #include "llvm/Support/ToolOutputFile.h"
  27 #include "llvm/Support/raw_ostream.h"
  28
  29 #if !defined(_MSC_VER) && !defined(__MINGW32__)
  30 #include <unistd.h>
  31 #else
  32 #include <io.h>
  33 #endif
  34
  35 using namespace llvm;
  36
  37 NewArchiveIterator::NewArchiveIterator(object::Archive::child_iterator I,
  38                                        StringRef Name)
  39     : IsNewMember(false), Name(Name), OldI(I) {}
  40
  41 NewArchiveIterator::NewArchiveIterator(StringRef NewFilename, StringRef Name)
  42     : IsNewMember(true), Name(Name), NewFilename(NewFilename) {}
  43
  44 StringRef NewArchiveIterator::getName() const { return Name; }
  45
  46 bool NewArchiveIterator::isNewMember() const { return IsNewMember; }
  47
  48 object::Archive::child_iterator NewArchiveIterator::getOld() const {
  49   assert(!IsNewMember);
  50   return OldI;
  51 }
  52
  53 StringRef NewArchiveIterator::getNew() const {
  54   assert(IsNewMember);
  55   return NewFilename;
  56 }
  57
  58 llvm::ErrorOr<int>
  59 NewArchiveIterator::getFD(sys::fs::file_status &NewStatus) const {
  60   assert(IsNewMember);
  61   int NewFD;
  62   if (auto EC = sys::fs::openFileForRead(NewFilename, NewFD))
  63     return EC;
  64   assert(NewFD != -1);
  65
  66   if (auto EC = sys::fs::status(NewFD, NewStatus))
  67     return EC;
  68
  69   // Opening a directory doesn't make sense. Let it fail.
  70   // Linux cannot open directories with open(2), although
  71   // cygwin and *bsd can.
  72   if (NewStatus.type() == sys::fs::file_type::directory_file)
  73     return make_error_code(errc::is_a_directory);
  74
  75   return NewFD;
  76 }
  77
  78 template <typename T>
  79 static void printWithSpacePadding(raw_fd_ostream &OS, T Data, unsigned Size,
  80                                   bool MayTruncate = false) {
  81   uint64_t OldPos = OS.tell();
  82   OS << Data;
  83   unsigned SizeSoFar = OS.tell() - OldPos;
  84   if (Size > SizeSoFar) {
  85     OS.indent(Size - SizeSoFar);
  86   } else if (Size < SizeSoFar) {
  87     assert(MayTruncate && "Data doesn't fit in Size");
  88     // Some of the data this is used for (like UID) can be larger than the
  89     // space available in the archive format. Truncate in that case.
  90     OS.seek(OldPos + Size);
  91   }
  92 }
  93
  94 static void print32(raw_ostream &Out, object::Archive::Kind Kind,
  95                     uint32_t Val) {
  96   if (Kind == object::Archive::K_GNU)
  97     support::endian::Writer<support::big>(Out).write(Val);
  98   else
  99     support::endian::Writer<support::little>(Out).write(Val);
 100 }
 101
 102 static void printRestOfMemberHeader(raw_fd_ostream &Out,
 103                                     const sys::TimeValue &ModTime, unsigned UID,
 104                                     unsigned GID, unsigned Perms,
 105                                     unsigned Size) {
 106   printWithSpacePadding(Out, ModTime.toEpochTime(), 12);
 107   printWithSpacePadding(Out, UID, 6, true);
 108   printWithSpacePadding(Out, GID, 6, true);
 109   printWithSpacePadding(Out, format("%o", Perms), 8);
 110   printWithSpacePadding(Out, Size, 10);
 111   Out << "`\n";
 112 }
 113
 114 static void printGNUSmallMemberHeader(raw_fd_ostream &Out, StringRef Name,
 115                                       const sys::TimeValue &ModTime,
 116                                       unsigned UID, unsigned GID,
 117                                       unsigned Perms, unsigned Size) {
 118   printWithSpacePadding(Out, Twine(Name) + "/", 16);
 119   printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
 120 }
 121
 122 static void printBSDMemberHeader(raw_fd_ostream &Out, StringRef Name,
 123                                  const sys::TimeValue &ModTime, unsigned UID,
 124                                  unsigned GID, unsigned Perms, unsigned Size) {
 125   uint64_t PosAfterHeader = Out.tell() + 60 + Name.size();
 126   // Pad so that even 64 bit object files are aligned.
 127   unsigned Pad = OffsetToAlignment(PosAfterHeader, 8);
 128   unsigned NameWithPadding = Name.size() + Pad;
 129   printWithSpacePadding(Out, Twine("#1/") + Twine(NameWithPadding), 16);
 130   printRestOfMemberHeader(Out, ModTime, UID, GID, Perms,
 131                           NameWithPadding + Size);
 132   Out << Name;
 133   assert(PosAfterHeader == Out.tell());
 134   while (Pad--)
 135     Out.write(uint8_t(0));
 136 }
 137
 138 static void
 139 printMemberHeader(raw_fd_ostream &Out, object::Archive::Kind Kind,
 140                   StringRef Name,
 141                   std::vector<unsigned>::iterator &StringMapIndexIter,
 142                   const sys::TimeValue &ModTime, unsigned UID, unsigned GID,
 143                   unsigned Perms, unsigned Size) {
 144   if (Kind == object::Archive::K_BSD)
 145     return printBSDMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
 146   if (Name.size() < 16)
 147     return printGNUSmallMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
 148   Out << '/';
 149   printWithSpacePadding(Out, *StringMapIndexIter++, 15);
 150   printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
 151 }
 152
 153 static void writeStringTable(raw_fd_ostream &Out,
 154                              ArrayRef<NewArchiveIterator> Members,
 155                              std::vector<unsigned> &StringMapIndexes) {
 156   unsigned StartOffset = 0;
 157   for (ArrayRef<NewArchiveIterator>::iterator I = Members.begin(),
 158                                               E = Members.end();
 159        I != E; ++I) {
 160     StringRef Name = I->getName();
 161     if (Name.size() < 16)
 162       continue;
 163     if (StartOffset == 0) {
 164       printWithSpacePadding(Out, "//", 58);
 165       Out << "`\n";
 166       StartOffset = Out.tell();
 167     }
 168     StringMapIndexes.push_back(Out.tell() - StartOffset);
 169     Out << Name << "/\n";
 170   }
 171   if (StartOffset == 0)
 172     return;
 173   if (Out.tell() % 2)
 174     Out << '\n';
 175   int Pos = Out.tell();
 176   Out.seek(StartOffset - 12);
 177   printWithSpacePadding(Out, Pos - StartOffset, 10);
 178   Out.seek(Pos);
 179 }
 180
 181 // Returns the offset of the first reference to a member offset.
 182 static ErrorOr<unsigned>
 183 writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
 184                  ArrayRef<NewArchiveIterator> Members,
 185                  ArrayRef<MemoryBufferRef> Buffers,
 186                  std::vector<unsigned> &MemberOffsetRefs) {
 187   unsigned HeaderStartOffset = 0;
 188   unsigned BodyStartOffset = 0;
 189   SmallString<128> NameBuf;
 190   raw_svector_ostream NameOS(NameBuf);
 191   LLVMContext Context;
 192   for (unsigned MemberNum = 0, N = Members.size(); MemberNum < N; ++MemberNum) {
 193     MemoryBufferRef MemberBuffer = Buffers[MemberNum];
 194     ErrorOr<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
 195         object::SymbolicFile::createSymbolicFile(
 196             MemberBuffer, sys::fs::file_magic::unknown, &Context);
 197     if (!ObjOrErr)
 198       continue;  // FIXME: check only for "not an object file" errors.
 199     object::SymbolicFile &Obj = *ObjOrErr.get();
 200
 201     if (!HeaderStartOffset) {
 202       HeaderStartOffset = Out.tell();
 203       if (Kind == object::Archive::K_GNU)
 204         printGNUSmallMemberHeader(Out, "", sys::TimeValue::now(), 0, 0, 0, 0);
 205       else
 206         printBSDMemberHeader(Out, "__.SYMDEF", sys::TimeValue::now(), 0, 0, 0,
 207                              0);
 208       BodyStartOffset = Out.tell();
 209       print32(Out, Kind, 0); // number of entries or bytes
 210     }
 211
 212     for (const object::BasicSymbolRef &S : Obj.symbols()) {
 213       uint32_t Symflags = S.getFlags();
 214       if (Symflags & object::SymbolRef::SF_FormatSpecific)
 215         continue;
 216       if (!(Symflags & object::SymbolRef::SF_Global))
 217         continue;
 218       if (Symflags & object::SymbolRef::SF_Undefined)
 219         continue;
 220
 221       unsigned NameOffset = NameOS.tell();
 222       if (auto EC = S.printName(NameOS))
 223         return EC;
 224       NameOS << '\0';
 225       MemberOffsetRefs.push_back(MemberNum);
 226       if (Kind == object::Archive::K_BSD)
 227         print32(Out, Kind, NameOffset);
 228       print32(Out, Kind, 0); // member offset
 229     }
 230   }
 231
 232   if (HeaderStartOffset == 0)
 233     return 0;
 234
 235   StringRef StringTable = NameOS.str();
 236   if (Kind == object::Archive::K_BSD)
 237     print32(Out, Kind, StringTable.size()); // byte count of the string table
 238   Out << StringTable;
 239
 240   // ld64 requires the next member header to start at an offset that is
 241   // 4 bytes aligned.
 242   unsigned Pad = OffsetToAlignment(Out.tell(), 4);
 243   while (Pad--)
 244     Out.write(uint8_t(0));
 245
 246   // Patch up the size of the symbol table now that we know how big it is.
 247   unsigned Pos = Out.tell();
 248   const unsigned MemberHeaderSize = 60;
 249   Out.seek(HeaderStartOffset + 48); // offset of the size field.
 250   printWithSpacePadding(Out, Pos - MemberHeaderSize - HeaderStartOffset, 10);
 251
 252   // Patch up the number of symbols.
 253   Out.seek(BodyStartOffset);
 254   unsigned NumSyms = MemberOffsetRefs.size();
 255   if (Kind == object::Archive::K_GNU)
 256     print32(Out, Kind, NumSyms);
 257   else
 258     print32(Out, Kind, NumSyms * 8);
 259
 260   Out.seek(Pos);
 261   return BodyStartOffset + 4;
 262 }
 263
 264 std::pair<StringRef, std::error_code>
 265 llvm::writeArchive(StringRef ArcName,
 266                    std::vector<NewArchiveIterator> &NewMembers,
 267                    bool WriteSymtab, object::Archive::Kind Kind) {
 268   SmallString<128> TmpArchive;
 269   int TmpArchiveFD;
 270   if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
 271                                           TmpArchiveFD, TmpArchive))
 272     return std::make_pair(ArcName, EC);
 273
 274   tool_output_file Output(TmpArchive, TmpArchiveFD);
 275   raw_fd_ostream &Out = Output.os();
 276   Out << "!<arch>\n";
 277
 278   std::vector<unsigned> MemberOffsetRefs;
 279
 280   std::vector<std::unique_ptr<MemoryBuffer>> Buffers;
 281   std::vector<MemoryBufferRef> Members;
 282   std::vector<sys::fs::file_status> NewMemberStatus;
 283
 284   for (unsigned I = 0, N = NewMembers.size(); I < N; ++I) {
 285     NewArchiveIterator &Member = NewMembers[I];
 286     MemoryBufferRef MemberRef;
 287
 288     if (Member.isNewMember()) {
 289       StringRef Filename = Member.getNew();
 290       NewMemberStatus.resize(NewMemberStatus.size() + 1);
 291       sys::fs::file_status &Status = NewMemberStatus.back();
 292       ErrorOr<int> FD = Member.getFD(Status);
 293       if (auto EC = FD.getError())
 294         return std::make_pair(Filename, EC);
 295       ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
 296           MemoryBuffer::getOpenFile(FD.get(), Filename, Status.getSize(),
 297                                     false);
 298       if (auto EC = MemberBufferOrErr.getError())
 299         return std::make_pair(Filename, EC);
 300       if (close(FD.get()) != 0)
 301         return std::make_pair(Filename,
 302                               std::error_code(errno, std::generic_category()));
 303       Buffers.push_back(std::move(MemberBufferOrErr.get()));
 304       MemberRef = Buffers.back()->getMemBufferRef();
 305     } else {
 306       object::Archive::child_iterator OldMember = Member.getOld();
 307       ErrorOr<MemoryBufferRef> MemberBufferOrErr =
 308           OldMember->getMemoryBufferRef();
 309       if (auto EC = MemberBufferOrErr.getError())
 310         return std::make_pair("", EC);
 311       MemberRef = MemberBufferOrErr.get();
 312     }
 313     Members.push_back(MemberRef);
 314   }
 315
 316   unsigned MemberReferenceOffset = 0;
 317   if (WriteSymtab) {
 318     ErrorOr<unsigned> MemberReferenceOffsetOrErr =
 319         writeSymbolTable(Out, Kind, NewMembers, Members, MemberOffsetRefs);
 320     if (auto EC = MemberReferenceOffsetOrErr.getError())
 321       return std::make_pair(ArcName, EC);
 322     MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
 323   }
 324
 325   std::vector<unsigned> StringMapIndexes;
 326   if (Kind != object::Archive::K_BSD)
 327     writeStringTable(Out, NewMembers, StringMapIndexes);
 328
 329   unsigned MemberNum = 0;
 330   unsigned NewMemberNum = 0;
 331   std::vector<unsigned>::iterator StringMapIndexIter = StringMapIndexes.begin();
 332   std::vector<unsigned> MemberOffset;
 333   for (const NewArchiveIterator &I : NewMembers) {
 334     MemoryBufferRef File = Members[MemberNum++];
 335
 336     unsigned Pos = Out.tell();
 337     MemberOffset.push_back(Pos);
 338
 339     if (I.isNewMember()) {
 340       StringRef FileName = I.getNew();
 341       const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum++];
 342       printMemberHeader(Out, Kind, sys::path::filename(FileName),
 343                         StringMapIndexIter, Status.getLastModificationTime(),
 344                         Status.getUser(), Status.getGroup(),
 345                         Status.permissions(), Status.getSize());
 346     } else {
 347       object::Archive::child_iterator OldMember = I.getOld();
 348       printMemberHeader(Out, Kind, I.getName(), StringMapIndexIter,
 349                         OldMember->getLastModified(), OldMember->getUID(),
 350                         OldMember->getGID(), OldMember->getAccessMode(),
 351                         OldMember->getSize());
 352     }
 353
 354     Out << File.getBuffer();
 355
 356     if (Out.tell() % 2)
 357       Out << '\n';
 358   }
 359
 360   if (MemberReferenceOffset) {
 361     Out.seek(MemberReferenceOffset);
 362     for (unsigned MemberNum : MemberOffsetRefs) {
 363       if (Kind == object::Archive::K_BSD)
 364         Out.seek(Out.tell() + 4); // skip over the string offset
 365       print32(Out, Kind, MemberOffset[MemberNum]);
 366     }
 367   }
 368
 369   Output.keep();
 370   Out.close();
 371   sys::fs::rename(TmpArchive, ArcName);
 372   return std::make_pair("", std::error_code());
 373 }