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(const object::Archive::Child &OldMember,
  38                                        StringRef Name)
  39     : IsNewMember(false), Name(Name), OldMember(OldMember) {}
  40
  41 NewArchiveIterator::NewArchiveIterator(StringRef FileName)
  42     : IsNewMember(true), Name(FileName), OldMember(nullptr, nullptr, nullptr) {}
  43
  44 StringRef NewArchiveIterator::getName() const { return Name; }
  45
  46 bool NewArchiveIterator::isNewMember() const { return IsNewMember; }
  47
  48 const object::Archive::Child &NewArchiveIterator::getOld() const {
  49   assert(!IsNewMember);
  50   return OldMember;
  51 }
  52
  53 StringRef NewArchiveIterator::getNew() const {
  54   assert(IsNewMember);
  55   return Name;
  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(Name, 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 // Compute the relative path from From to To.
 158 static std::string computeRelativePath(StringRef From, StringRef To) {
 159   if (sys::path::is_absolute(From) || sys::path::is_absolute(To))
 160     return To;
 161
 162   StringRef DirFrom = sys::path::parent_path(From);
 163   auto FromI = sys::path::begin(DirFrom);
 164   auto ToI = sys::path::begin(To);
 165   while (*FromI == *ToI) {
 166     ++FromI;
 167     ++ToI;
 168   }
 169
 170   SmallString<128> Relative;
 171   for (auto FromE = sys::path::end(DirFrom); FromI != FromE; ++FromI)
 172     sys::path::append(Relative, "..");
 173
 174   for (auto ToE = sys::path::end(To); ToI != ToE; ++ToI)
 175     sys::path::append(Relative, *ToI);
 176
 177   return Relative.str();
 178 }
 179
 180 static void writeStringTable(raw_fd_ostream &Out, StringRef ArcName,
 181                              ArrayRef<NewArchiveIterator> Members,
 182                              std::vector<unsigned> &StringMapIndexes,
 183                              bool Thin) {
 184   unsigned StartOffset = 0;
 185   for (const NewArchiveIterator &I : Members) {
 186     StringRef Name = sys::path::filename(I.getName());
 187     if (!useStringTable(Thin, Name))
 188       continue;
 189     if (StartOffset == 0) {
 190       printWithSpacePadding(Out, "//", 58);
 191       Out << "`\n";
 192       StartOffset = Out.tell();
 193     }
 194     StringMapIndexes.push_back(Out.tell() - StartOffset);
 195
 196     if (Thin)
 197       Out << computeRelativePath(ArcName, I.getName());
 198     else
 199       Out << Name;
 200
 201     Out << "/\n";
 202   }
 203   if (StartOffset == 0)
 204     return;
 205   if (Out.tell() % 2)
 206     Out << '\n';
 207   int Pos = Out.tell();
 208   Out.seek(StartOffset - 12);
 209   printWithSpacePadding(Out, Pos - StartOffset, 10);
 210   Out.seek(Pos);
 211 }
 212
 213 static sys::TimeValue now(bool Deterministic) {
 214   if (!Deterministic)
 215     return sys::TimeValue::now();
 216   sys::TimeValue TV;
 217   TV.fromEpochTime(0);
 218   return TV;
 219 }
 220
 221 // Returns the offset of the first reference to a member offset.
 222 static ErrorOr<unsigned>
 223 writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
 224                  ArrayRef<NewArchiveIterator> Members,
 225                  ArrayRef<MemoryBufferRef> Buffers,
 226                  std::vector<unsigned> &MemberOffsetRefs, bool Deterministic) {
 227   unsigned HeaderStartOffset = 0;
 228   unsigned BodyStartOffset = 0;
 229   SmallString<128> NameBuf;
 230   raw_svector_ostream NameOS(NameBuf);
 231   LLVMContext Context;
 232   for (unsigned MemberNum = 0, N = Members.size(); MemberNum < N; ++MemberNum) {
 233     MemoryBufferRef MemberBuffer = Buffers[MemberNum];
 234     ErrorOr<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
 235         object::SymbolicFile::createSymbolicFile(
 236             MemberBuffer, sys::fs::file_magic::unknown, &Context);
 237     if (!ObjOrErr)
 238       continue;  // FIXME: check only for "not an object file" errors.
 239     object::SymbolicFile &Obj = *ObjOrErr.get();
 240
 241     if (!HeaderStartOffset) {
 242       HeaderStartOffset = Out.tell();
 243       if (Kind == object::Archive::K_GNU)
 244         printGNUSmallMemberHeader(Out, "", now(Deterministic), 0, 0, 0, 0);
 245       else
 246         printBSDMemberHeader(Out, "__.SYMDEF", now(Deterministic), 0, 0, 0, 0);
 247       BodyStartOffset = Out.tell();
 248       print32(Out, Kind, 0); // number of entries or bytes
 249     }
 250
 251     for (const object::BasicSymbolRef &S : Obj.symbols()) {
 252       uint32_t Symflags = S.getFlags();
 253       if (Symflags & object::SymbolRef::SF_FormatSpecific)
 254         continue;
 255       if (!(Symflags & object::SymbolRef::SF_Global))
 256         continue;
 257       if (Symflags & object::SymbolRef::SF_Undefined)
 258         continue;
 259
 260       unsigned NameOffset = NameOS.tell();
 261       if (auto EC = S.printName(NameOS))
 262         return EC;
 263       NameOS << '\0';
 264       MemberOffsetRefs.push_back(MemberNum);
 265       if (Kind == object::Archive::K_BSD)
 266         print32(Out, Kind, NameOffset);
 267       print32(Out, Kind, 0); // member offset
 268     }
 269   }
 270
 271   if (HeaderStartOffset == 0)
 272     return 0;
 273
 274   StringRef StringTable = NameOS.str();
 275   if (Kind == object::Archive::K_BSD)
 276     print32(Out, Kind, StringTable.size()); // byte count of the string table
 277   Out << StringTable;
 278
 279   // ld64 requires the next member header to start at an offset that is
 280   // 4 bytes aligned.
 281   unsigned Pad = OffsetToAlignment(Out.tell(), 4);
 282   while (Pad--)
 283     Out.write(uint8_t(0));
 284
 285   // Patch up the size of the symbol table now that we know how big it is.
 286   unsigned Pos = Out.tell();
 287   const unsigned MemberHeaderSize = 60;
 288   Out.seek(HeaderStartOffset + 48); // offset of the size field.
 289   printWithSpacePadding(Out, Pos - MemberHeaderSize - HeaderStartOffset, 10);
 290
 291   // Patch up the number of symbols.
 292   Out.seek(BodyStartOffset);
 293   unsigned NumSyms = MemberOffsetRefs.size();
 294   if (Kind == object::Archive::K_GNU)
 295     print32(Out, Kind, NumSyms);
 296   else
 297     print32(Out, Kind, NumSyms * 8);
 298
 299   Out.seek(Pos);
 300   return BodyStartOffset + 4;
 301 }
 302
 303 std::pair<StringRef, std::error_code>
 304 llvm::writeArchive(StringRef ArcName,
 305                    std::vector<NewArchiveIterator> &NewMembers,
 306                    bool WriteSymtab, object::Archive::Kind Kind,
 307                    bool Deterministic, bool Thin) {
 308   SmallString<128> TmpArchive;
 309   int TmpArchiveFD;
 310   if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
 311                                           TmpArchiveFD, TmpArchive))
 312     return std::make_pair(ArcName, EC);
 313
 314   tool_output_file Output(TmpArchive, TmpArchiveFD);
 315   raw_fd_ostream &Out = Output.os();
 316   if (Thin)
 317     Out << "!<thin>\n";
 318   else
 319     Out << "!<arch>\n";
 320
 321   std::vector<unsigned> MemberOffsetRefs;
 322
 323   std::vector<std::unique_ptr<MemoryBuffer>> Buffers;
 324   std::vector<MemoryBufferRef> Members;
 325   std::vector<sys::fs::file_status> NewMemberStatus;
 326
 327   for (unsigned I = 0, N = NewMembers.size(); I < N; ++I) {
 328     NewArchiveIterator &Member = NewMembers[I];
 329     MemoryBufferRef MemberRef;
 330
 331     if (Member.isNewMember()) {
 332       StringRef Filename = Member.getNew();
 333       NewMemberStatus.resize(NewMemberStatus.size() + 1);
 334       sys::fs::file_status &Status = NewMemberStatus.back();
 335       ErrorOr<int> FD = Member.getFD(Status);
 336       if (auto EC = FD.getError())
 337         return std::make_pair(Filename, EC);
 338       ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
 339           MemoryBuffer::getOpenFile(FD.get(), Filename, Status.getSize(),
 340                                     false);
 341       if (auto EC = MemberBufferOrErr.getError())
 342         return std::make_pair(Filename, EC);
 343       if (close(FD.get()) != 0)
 344         return std::make_pair(Filename,
 345                               std::error_code(errno, std::generic_category()));
 346       Buffers.push_back(std::move(MemberBufferOrErr.get()));
 347       MemberRef = Buffers.back()->getMemBufferRef();
 348     } else {
 349       const object::Archive::Child &OldMember = Member.getOld();
 350       assert((!Thin || OldMember.getParent()->isThin()) &&
 351              "Thin archives cannot refers to member of other archives");
 352       ErrorOr<MemoryBufferRef> MemberBufferOrErr =
 353           OldMember.getMemoryBufferRef();
 354       if (auto EC = MemberBufferOrErr.getError())
 355         return std::make_pair("", EC);
 356       MemberRef = MemberBufferOrErr.get();
 357     }
 358     Members.push_back(MemberRef);
 359   }
 360
 361   unsigned MemberReferenceOffset = 0;
 362   if (WriteSymtab) {
 363     ErrorOr<unsigned> MemberReferenceOffsetOrErr = writeSymbolTable(
 364         Out, Kind, NewMembers, Members, MemberOffsetRefs, Deterministic);
 365     if (auto EC = MemberReferenceOffsetOrErr.getError())
 366       return std::make_pair(ArcName, EC);
 367     MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
 368   }
 369
 370   std::vector<unsigned> StringMapIndexes;
 371   if (Kind != object::Archive::K_BSD)
 372     writeStringTable(Out, ArcName, NewMembers, StringMapIndexes, Thin);
 373
 374   unsigned MemberNum = 0;
 375   unsigned NewMemberNum = 0;
 376   std::vector<unsigned>::iterator StringMapIndexIter = StringMapIndexes.begin();
 377   std::vector<unsigned> MemberOffset;
 378   for (const NewArchiveIterator &I : NewMembers) {
 379     MemoryBufferRef File = Members[MemberNum++];
 380
 381     unsigned Pos = Out.tell();
 382     MemberOffset.push_back(Pos);
 383
 384     sys::TimeValue ModTime;
 385     unsigned UID;
 386     unsigned GID;
 387     unsigned Perms;
 388     if (Deterministic) {
 389       ModTime.fromEpochTime(0);
 390       UID = 0;
 391       GID = 0;
 392       Perms = 0644;
 393     } else if (I.isNewMember()) {
 394       const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum];
 395       ModTime = Status.getLastModificationTime();
 396       UID = Status.getUser();
 397       GID = Status.getGroup();
 398       Perms = Status.permissions();
 399     } else {
 400       const object::Archive::Child &OldMember = I.getOld();
 401       ModTime = OldMember.getLastModified();
 402       UID = OldMember.getUID();
 403       GID = OldMember.getGID();
 404       Perms = OldMember.getAccessMode();
 405     }
 406
 407     if (I.isNewMember()) {
 408       StringRef FileName = I.getNew();
 409       const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum++];
 410       printMemberHeader(Out, Kind, Thin, sys::path::filename(FileName),
 411                         StringMapIndexIter, ModTime, UID, GID, Perms,
 412                         Status.getSize());
 413     } else {
 414       const object::Archive::Child &OldMember = I.getOld();
 415       ErrorOr<uint32_t> Size = OldMember.getSize();
 416       if (std::error_code EC = Size.getError())
 417         return std::make_pair("", EC);
 418       printMemberHeader(Out, Kind, Thin, I.getName(), StringMapIndexIter,
 419                         ModTime, UID, GID, Perms, Size.get());
 420     }
 421
 422     if (!Thin)
 423       Out << File.getBuffer();
 424
 425     if (Out.tell() % 2)
 426       Out << '\n';
 427   }
 428
 429   if (MemberReferenceOffset) {
 430     Out.seek(MemberReferenceOffset);
 431     for (unsigned MemberNum : MemberOffsetRefs) {
 432       if (Kind == object::Archive::K_BSD)
 433         Out.seek(Out.tell() + 4); // skip over the string offset
 434       print32(Out, Kind, MemberOffset[MemberNum]);
 435     }
 436   }
 437
 438   Output.keep();
 439   Out.close();
 440   sys::fs::rename(TmpArchive, ArcName);
 441   return std::make_pair("", std::error_code());
 442 }