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 bool useStringTable(bool Thin, StringRef Name) {
 139   return Thin || Name.size() >= 16;
 140 }
 141
 142 static void
 143 printMemberHeader(raw_fd_ostream &Out, object::Archive::Kind Kind, bool Thin,
 144                   StringRef Name,
 145                   std::vector<unsigned>::iterator &StringMapIndexIter,
 146                   const sys::TimeValue &ModTime, unsigned UID, unsigned GID,
 147                   unsigned Perms, unsigned Size) {
 148   if (Kind == object::Archive::K_BSD)
 149     return printBSDMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
 150   if (!useStringTable(Thin, Name))
 151     return printGNUSmallMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
 152   Out << '/';
 153   printWithSpacePadding(Out, *StringMapIndexIter++, 15);
 154   printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
 155 }
 156
 157 static void writeStringTable(raw_fd_ostream &Out,
 158                              ArrayRef<NewArchiveIterator> Members,
 159                              std::vector<unsigned> &StringMapIndexes,
 160                              bool Thin) {
 161   unsigned StartOffset = 0;
 162   for (const NewArchiveIterator &I : Members) {
 163     StringRef Name = I.getName();
 164     if (!useStringTable(Thin, Name))
 165       continue;
 166     if (StartOffset == 0) {
 167       printWithSpacePadding(Out, "//", 58);
 168       Out << "`\n";
 169       StartOffset = Out.tell();
 170     }
 171     StringMapIndexes.push_back(Out.tell() - StartOffset);
 172     Out << Name << "/\n";
 173   }
 174   if (StartOffset == 0)
 175     return;
 176   if (Out.tell() % 2)
 177     Out << '\n';
 178   int Pos = Out.tell();
 179   Out.seek(StartOffset - 12);
 180   printWithSpacePadding(Out, Pos - StartOffset, 10);
 181   Out.seek(Pos);
 182 }
 183
 184 static sys::TimeValue now(bool Deterministic) {
 185   if (!Deterministic)
 186     return sys::TimeValue::now();
 187   sys::TimeValue TV;
 188   TV.fromEpochTime(0);
 189   return TV;
 190 }
 191
 192 // Returns the offset of the first reference to a member offset.
 193 static ErrorOr<unsigned>
 194 writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
 195                  ArrayRef<NewArchiveIterator> Members,
 196                  ArrayRef<MemoryBufferRef> Buffers,
 197                  std::vector<unsigned> &MemberOffsetRefs, bool Deterministic) {
 198   unsigned HeaderStartOffset = 0;
 199   unsigned BodyStartOffset = 0;
 200   SmallString<128> NameBuf;
 201   raw_svector_ostream NameOS(NameBuf);
 202   LLVMContext Context;
 203   for (unsigned MemberNum = 0, N = Members.size(); MemberNum < N; ++MemberNum) {
 204     MemoryBufferRef MemberBuffer = Buffers[MemberNum];
 205     ErrorOr<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
 206         object::SymbolicFile::createSymbolicFile(
 207             MemberBuffer, sys::fs::file_magic::unknown, &Context);
 208     if (!ObjOrErr)
 209       continue;  // FIXME: check only for "not an object file" errors.
 210     object::SymbolicFile &Obj = *ObjOrErr.get();
 211
 212     if (!HeaderStartOffset) {
 213       HeaderStartOffset = Out.tell();
 214       if (Kind == object::Archive::K_GNU)
 215         printGNUSmallMemberHeader(Out, "", now(Deterministic), 0, 0, 0, 0);
 216       else
 217         printBSDMemberHeader(Out, "__.SYMDEF", now(Deterministic), 0, 0, 0, 0);
 218       BodyStartOffset = Out.tell();
 219       print32(Out, Kind, 0); // number of entries or bytes
 220     }
 221
 222     for (const object::BasicSymbolRef &S : Obj.symbols()) {
 223       uint32_t Symflags = S.getFlags();
 224       if (Symflags & object::SymbolRef::SF_FormatSpecific)
 225         continue;
 226       if (!(Symflags & object::SymbolRef::SF_Global))
 227         continue;
 228       if (Symflags & object::SymbolRef::SF_Undefined)
 229         continue;
 230
 231       unsigned NameOffset = NameOS.tell();
 232       if (auto EC = S.printName(NameOS))
 233         return EC;
 234       NameOS << '\0';
 235       MemberOffsetRefs.push_back(MemberNum);
 236       if (Kind == object::Archive::K_BSD)
 237         print32(Out, Kind, NameOffset);
 238       print32(Out, Kind, 0); // member offset
 239     }
 240   }
 241
 242   if (HeaderStartOffset == 0)
 243     return 0;
 244
 245   StringRef StringTable = NameOS.str();
 246   if (Kind == object::Archive::K_BSD)
 247     print32(Out, Kind, StringTable.size()); // byte count of the string table
 248   Out << StringTable;
 249
 250   // ld64 requires the next member header to start at an offset that is
 251   // 4 bytes aligned.
 252   unsigned Pad = OffsetToAlignment(Out.tell(), 4);
 253   while (Pad--)
 254     Out.write(uint8_t(0));
 255
 256   // Patch up the size of the symbol table now that we know how big it is.
 257   unsigned Pos = Out.tell();
 258   const unsigned MemberHeaderSize = 60;
 259   Out.seek(HeaderStartOffset + 48); // offset of the size field.
 260   printWithSpacePadding(Out, Pos - MemberHeaderSize - HeaderStartOffset, 10);
 261
 262   // Patch up the number of symbols.
 263   Out.seek(BodyStartOffset);
 264   unsigned NumSyms = MemberOffsetRefs.size();
 265   if (Kind == object::Archive::K_GNU)
 266     print32(Out, Kind, NumSyms);
 267   else
 268     print32(Out, Kind, NumSyms * 8);
 269
 270   Out.seek(Pos);
 271   return BodyStartOffset + 4;
 272 }
 273
 274 std::pair<StringRef, std::error_code>
 275 llvm::writeArchive(StringRef ArcName,
 276                    std::vector<NewArchiveIterator> &NewMembers,
 277                    bool WriteSymtab, object::Archive::Kind Kind,
 278                    bool Deterministic, bool Thin) {
 279   SmallString<128> TmpArchive;
 280   int TmpArchiveFD;
 281   if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
 282                                           TmpArchiveFD, TmpArchive))
 283     return std::make_pair(ArcName, EC);
 284
 285   tool_output_file Output(TmpArchive, TmpArchiveFD);
 286   raw_fd_ostream &Out = Output.os();
 287   if (Thin)
 288     Out << "!<thin>\n";
 289   else
 290     Out << "!<arch>\n";
 291
 292   std::vector<unsigned> MemberOffsetRefs;
 293
 294   std::vector<std::unique_ptr<MemoryBuffer>> Buffers;
 295   std::vector<MemoryBufferRef> Members;
 296   std::vector<sys::fs::file_status> NewMemberStatus;
 297
 298   for (unsigned I = 0, N = NewMembers.size(); I < N; ++I) {
 299     NewArchiveIterator &Member = NewMembers[I];
 300     MemoryBufferRef MemberRef;
 301
 302     if (Member.isNewMember()) {
 303       StringRef Filename = Member.getNew();
 304       NewMemberStatus.resize(NewMemberStatus.size() + 1);
 305       sys::fs::file_status &Status = NewMemberStatus.back();
 306       ErrorOr<int> FD = Member.getFD(Status);
 307       if (auto EC = FD.getError())
 308         return std::make_pair(Filename, EC);
 309       ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
 310           MemoryBuffer::getOpenFile(FD.get(), Filename, Status.getSize(),
 311                                     false);
 312       if (auto EC = MemberBufferOrErr.getError())
 313         return std::make_pair(Filename, EC);
 314       if (close(FD.get()) != 0)
 315         return std::make_pair(Filename,
 316                               std::error_code(errno, std::generic_category()));
 317       Buffers.push_back(std::move(MemberBufferOrErr.get()));
 318       MemberRef = Buffers.back()->getMemBufferRef();
 319     } else {
 320       object::Archive::child_iterator OldMember = Member.getOld();
 321       ErrorOr<MemoryBufferRef> MemberBufferOrErr =
 322           OldMember->getMemoryBufferRef();
 323       if (auto EC = MemberBufferOrErr.getError())
 324         return std::make_pair("", EC);
 325       MemberRef = MemberBufferOrErr.get();
 326     }
 327     Members.push_back(MemberRef);
 328   }
 329
 330   unsigned MemberReferenceOffset = 0;
 331   if (WriteSymtab) {
 332     ErrorOr<unsigned> MemberReferenceOffsetOrErr = writeSymbolTable(
 333         Out, Kind, NewMembers, Members, MemberOffsetRefs, Deterministic);
 334     if (auto EC = MemberReferenceOffsetOrErr.getError())
 335       return std::make_pair(ArcName, EC);
 336     MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
 337   }
 338
 339   std::vector<unsigned> StringMapIndexes;
 340   if (Kind != object::Archive::K_BSD)
 341     writeStringTable(Out, NewMembers, StringMapIndexes, Thin);
 342
 343   unsigned MemberNum = 0;
 344   unsigned NewMemberNum = 0;
 345   std::vector<unsigned>::iterator StringMapIndexIter = StringMapIndexes.begin();
 346   std::vector<unsigned> MemberOffset;
 347   for (const NewArchiveIterator &I : NewMembers) {
 348     MemoryBufferRef File = Members[MemberNum++];
 349
 350     unsigned Pos = Out.tell();
 351     MemberOffset.push_back(Pos);
 352
 353     sys::TimeValue ModTime;
 354     unsigned UID;
 355     unsigned GID;
 356     unsigned Perms;
 357     if (Deterministic) {
 358       ModTime.fromEpochTime(0);
 359       UID = 0;
 360       GID = 0;
 361       Perms = 0644;
 362     } else if (I.isNewMember()) {
 363       const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum];
 364       ModTime = Status.getLastModificationTime();
 365       UID = Status.getUser();
 366       GID = Status.getGroup();
 367       Perms = Status.permissions();
 368     } else {
 369       object::Archive::child_iterator OldMember = I.getOld();
 370       ModTime = OldMember->getLastModified();
 371       UID = OldMember->getUID();
 372       GID = OldMember->getGID();
 373       Perms = OldMember->getAccessMode();
 374     }
 375
 376     if (I.isNewMember()) {
 377       StringRef FileName = I.getNew();
 378       const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum++];
 379       printMemberHeader(Out, Kind, Thin, sys::path::filename(FileName),
 380                         StringMapIndexIter, ModTime, UID, GID, Perms,
 381                         Status.getSize());
 382     } else {
 383       object::Archive::child_iterator OldMember = I.getOld();
 384       printMemberHeader(Out, Kind, Thin, I.getName(), StringMapIndexIter,
 385                         ModTime, UID, GID, Perms, OldMember->getSize());
 386     }
 387
 388     if (!Thin)
 389       Out << File.getBuffer();
 390
 391     if (Out.tell() % 2)
 392       Out << '\n';
 393   }
 394
 395   if (MemberReferenceOffset) {
 396     Out.seek(MemberReferenceOffset);
 397     for (unsigned MemberNum : MemberOffsetRefs) {
 398       if (Kind == object::Archive::K_BSD)
 399         Out.seek(Out.tell() + 4); // skip over the string offset
 400       print32(Out, Kind, MemberOffset[MemberNum]);
 401     }
 402   }
 403
 404   Output.keep();
 405   Out.close();
 406   sys::fs::rename(TmpArchive, ArcName);
 407   return std::make_pair("", std::error_code());
 408 }