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llvm/lib/Object/ArchiveWriter.cpp
Kevin Enderby 268709a810 Reapply r250906 with many suggested updates from Rafael Espindola. 
The needed lld matching changes to be submitted immediately next,
but this revision will cause lld failures with this alone which is expected.

This removes the eating of the error in Archive::Child::getSize() when the characters
in the size field in the archive header for the member is not a number.  To do this we
have all of the needed methods return ErrorOr to push them up until we get out of lib.
Then the tools and can handle the error in whatever way is appropriate for that tool.

So the solution is to plumb all the ErrorOr stuff through everything that touches archives.
This include its iterators as one can create an Archive object but the first or any other
Child object may fail to be created due to a bad size field in its header.

Thanks to Lang Hames on the changes making child_iterator contain an
ErrorOr<Child> instead of a Child and the needed changes to ErrorOr.h to add
operator overloading for * and -> .

We don’t want to use llvm_unreachable() as it calls abort() and is produces a “crash”
and using report_fatal_error() to move the error checking will cause the program to
stop, neither of which are really correct in library code. There are still some uses of
these that should be cleaned up in this library code for other than the size field.

The test cases use archives with text files so one can see the non-digit character,
in this case a ‘%’, in the size field.

These changes will require corresponding changes to the lld project.  That will be
committed immediately after this change.  But this revision will cause lld failures
with this alone which is expected.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252192 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-05 19:24:56 +00:00

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//===- ArchiveWriter.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 writeArchive function.
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/ArchiveWriter.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/SymbolicFile.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/raw_ostream.h"
#if !defined(_MSC_VER) && !defined(__MINGW32__)
#include <unistd.h>
#else
#include <io.h>
#endif
using namespace llvm;
NewArchiveIterator::NewArchiveIterator(const object::Archive::Child &OldMember,
StringRef Name)
: IsNewMember(false), Name(Name), OldMember(OldMember) {}
NewArchiveIterator::NewArchiveIterator(StringRef FileName)
: IsNewMember(true), Name(FileName), OldMember(nullptr, nullptr, nullptr) {}
StringRef NewArchiveIterator::getName() const { return Name; }
bool NewArchiveIterator::isNewMember() const { return IsNewMember; }
const object::Archive::Child &NewArchiveIterator::getOld() const {
assert(!IsNewMember);
return OldMember;
}
StringRef NewArchiveIterator::getNew() const {
assert(IsNewMember);
return Name;
}
llvm::ErrorOr<int>
NewArchiveIterator::getFD(sys::fs::file_status &NewStatus) const {
assert(IsNewMember);
int NewFD;
if (auto EC = sys::fs::openFileForRead(Name, NewFD))
return EC;
assert(NewFD != -1);
if (auto EC = sys::fs::status(NewFD, NewStatus))
return EC;
// Opening a directory doesn't make sense. Let it fail.
// Linux cannot open directories with open(2), although
// cygwin and *bsd can.
if (NewStatus.type() == sys::fs::file_type::directory_file)
return make_error_code(errc::is_a_directory);
return NewFD;
}
template <typename T>
static void printWithSpacePadding(raw_fd_ostream &OS, T Data, unsigned Size,
bool MayTruncate = false) {
uint64_t OldPos = OS.tell();
OS << Data;
unsigned SizeSoFar = OS.tell() - OldPos;
if (Size > SizeSoFar) {
OS.indent(Size - SizeSoFar);
} else if (Size < SizeSoFar) {
assert(MayTruncate && "Data doesn't fit in Size");
// Some of the data this is used for (like UID) can be larger than the
// space available in the archive format. Truncate in that case.
OS.seek(OldPos + Size);
}
}
static void print32(raw_ostream &Out, object::Archive::Kind Kind,
uint32_t Val) {
if (Kind == object::Archive::K_GNU)
support::endian::Writer<support::big>(Out).write(Val);
else
support::endian::Writer<support::little>(Out).write(Val);
}
static void printRestOfMemberHeader(raw_fd_ostream &Out,
const sys::TimeValue &ModTime, unsigned UID,
unsigned GID, unsigned Perms,
unsigned Size) {
printWithSpacePadding(Out, ModTime.toEpochTime(), 12);
printWithSpacePadding(Out, UID, 6, true);
printWithSpacePadding(Out, GID, 6, true);
printWithSpacePadding(Out, format("%o", Perms), 8);
printWithSpacePadding(Out, Size, 10);
Out << "`\n";
}
static void printGNUSmallMemberHeader(raw_fd_ostream &Out, StringRef Name,
const sys::TimeValue &ModTime,
unsigned UID, unsigned GID,
unsigned Perms, unsigned Size) {
printWithSpacePadding(Out, Twine(Name) + "/", 16);
printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
}
static void printBSDMemberHeader(raw_fd_ostream &Out, StringRef Name,
const sys::TimeValue &ModTime, unsigned UID,
unsigned GID, unsigned Perms, unsigned Size) {
uint64_t PosAfterHeader = Out.tell() + 60 + Name.size();
// Pad so that even 64 bit object files are aligned.
unsigned Pad = OffsetToAlignment(PosAfterHeader, 8);
unsigned NameWithPadding = Name.size() + Pad;
printWithSpacePadding(Out, Twine("#1/") + Twine(NameWithPadding), 16);
printRestOfMemberHeader(Out, ModTime, UID, GID, Perms,
NameWithPadding + Size);
Out << Name;
assert(PosAfterHeader == Out.tell());
while (Pad--)
Out.write(uint8_t(0));
}
static bool useStringTable(bool Thin, StringRef Name) {
return Thin || Name.size() >= 16;
}
static void
printMemberHeader(raw_fd_ostream &Out, object::Archive::Kind Kind, bool Thin,
StringRef Name,
std::vector<unsigned>::iterator &StringMapIndexIter,
const sys::TimeValue &ModTime, unsigned UID, unsigned GID,
unsigned Perms, unsigned Size) {
if (Kind == object::Archive::K_BSD)
return printBSDMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
if (!useStringTable(Thin, Name))
return printGNUSmallMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
Out << '/';
printWithSpacePadding(Out, *StringMapIndexIter++, 15);
printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
}
// Compute the relative path from From to To.
static std::string computeRelativePath(StringRef From, StringRef To) {
if (sys::path::is_absolute(From) || sys::path::is_absolute(To))
return To;
StringRef DirFrom = sys::path::parent_path(From);
auto FromI = sys::path::begin(DirFrom);
auto ToI = sys::path::begin(To);
while (*FromI == *ToI) {
++FromI;
++ToI;
}
SmallString<128> Relative;
for (auto FromE = sys::path::end(DirFrom); FromI != FromE; ++FromI)
sys::path::append(Relative, "..");
for (auto ToE = sys::path::end(To); ToI != ToE; ++ToI)
sys::path::append(Relative, *ToI);
return Relative.str();
}
static void writeStringTable(raw_fd_ostream &Out, StringRef ArcName,
ArrayRef<NewArchiveIterator> Members,
std::vector<unsigned> &StringMapIndexes,
bool Thin) {
unsigned StartOffset = 0;
for (const NewArchiveIterator &I : Members) {
StringRef Name = sys::path::filename(I.getName());
if (!useStringTable(Thin, Name))
continue;
if (StartOffset == 0) {
printWithSpacePadding(Out, "//", 58);
Out << "`\n";
StartOffset = Out.tell();
}
StringMapIndexes.push_back(Out.tell() - StartOffset);
if (Thin)
Out << computeRelativePath(ArcName, I.getName());
else
Out << Name;
Out << "/\n";
}
if (StartOffset == 0)
return;
if (Out.tell() % 2)
Out << '\n';
int Pos = Out.tell();
Out.seek(StartOffset - 12);
printWithSpacePadding(Out, Pos - StartOffset, 10);
Out.seek(Pos);
}
static sys::TimeValue now(bool Deterministic) {
if (!Deterministic)
return sys::TimeValue::now();
sys::TimeValue TV;
TV.fromEpochTime(0);
return TV;
}
// Returns the offset of the first reference to a member offset.
static ErrorOr<unsigned>
writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
ArrayRef<NewArchiveIterator> Members,
ArrayRef<MemoryBufferRef> Buffers,
std::vector<unsigned> &MemberOffsetRefs, bool Deterministic) {
unsigned HeaderStartOffset = 0;
unsigned BodyStartOffset = 0;
SmallString<128> NameBuf;
raw_svector_ostream NameOS(NameBuf);
LLVMContext Context;
for (unsigned MemberNum = 0, N = Members.size(); MemberNum < N; ++MemberNum) {
MemoryBufferRef MemberBuffer = Buffers[MemberNum];
ErrorOr<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
object::SymbolicFile::createSymbolicFile(
MemberBuffer, sys::fs::file_magic::unknown, &Context);
if (!ObjOrErr)
continue; // FIXME: check only for "not an object file" errors.
object::SymbolicFile &Obj = *ObjOrErr.get();
if (!HeaderStartOffset) {
HeaderStartOffset = Out.tell();
if (Kind == object::Archive::K_GNU)
printGNUSmallMemberHeader(Out, "", now(Deterministic), 0, 0, 0, 0);
else
printBSDMemberHeader(Out, "__.SYMDEF", now(Deterministic), 0, 0, 0, 0);
BodyStartOffset = Out.tell();
print32(Out, Kind, 0); // number of entries or bytes
}
for (const object::BasicSymbolRef &S : Obj.symbols()) {
uint32_t Symflags = S.getFlags();
if (Symflags & object::SymbolRef::SF_FormatSpecific)
continue;
if (!(Symflags & object::SymbolRef::SF_Global))
continue;
if (Symflags & object::SymbolRef::SF_Undefined)
continue;
unsigned NameOffset = NameOS.tell();
if (auto EC = S.printName(NameOS))
return EC;
NameOS << '\0';
MemberOffsetRefs.push_back(MemberNum);
if (Kind == object::Archive::K_BSD)
print32(Out, Kind, NameOffset);
print32(Out, Kind, 0); // member offset
}
}
if (HeaderStartOffset == 0)
return 0;
StringRef StringTable = NameOS.str();
if (Kind == object::Archive::K_BSD)
print32(Out, Kind, StringTable.size()); // byte count of the string table
Out << StringTable;
// ld64 requires the next member header to start at an offset that is
// 4 bytes aligned.
unsigned Pad = OffsetToAlignment(Out.tell(), 4);
while (Pad--)
Out.write(uint8_t(0));
// Patch up the size of the symbol table now that we know how big it is.
unsigned Pos = Out.tell();
const unsigned MemberHeaderSize = 60;
Out.seek(HeaderStartOffset + 48); // offset of the size field.
printWithSpacePadding(Out, Pos - MemberHeaderSize - HeaderStartOffset, 10);
// Patch up the number of symbols.
Out.seek(BodyStartOffset);
unsigned NumSyms = MemberOffsetRefs.size();
if (Kind == object::Archive::K_GNU)
print32(Out, Kind, NumSyms);
else
print32(Out, Kind, NumSyms * 8);
Out.seek(Pos);
return BodyStartOffset + 4;
}
std::pair<StringRef, std::error_code>
llvm::writeArchive(StringRef ArcName,
std::vector<NewArchiveIterator> &NewMembers,
bool WriteSymtab, object::Archive::Kind Kind,
bool Deterministic, bool Thin) {
SmallString<128> TmpArchive;
int TmpArchiveFD;
if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
TmpArchiveFD, TmpArchive))
return std::make_pair(ArcName, EC);
tool_output_file Output(TmpArchive, TmpArchiveFD);
raw_fd_ostream &Out = Output.os();
if (Thin)
Out << "!<thin>\n";
else
Out << "!<arch>\n";
std::vector<unsigned> MemberOffsetRefs;
std::vector<std::unique_ptr<MemoryBuffer>> Buffers;
std::vector<MemoryBufferRef> Members;
std::vector<sys::fs::file_status> NewMemberStatus;
for (unsigned I = 0, N = NewMembers.size(); I < N; ++I) {
NewArchiveIterator &Member = NewMembers[I];
MemoryBufferRef MemberRef;
if (Member.isNewMember()) {
StringRef Filename = Member.getNew();
NewMemberStatus.resize(NewMemberStatus.size() + 1);
sys::fs::file_status &Status = NewMemberStatus.back();
ErrorOr<int> FD = Member.getFD(Status);
if (auto EC = FD.getError())
return std::make_pair(Filename, EC);
ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
MemoryBuffer::getOpenFile(FD.get(), Filename, Status.getSize(),
false);
if (auto EC = MemberBufferOrErr.getError())
return std::make_pair(Filename, EC);
if (close(FD.get()) != 0)
return std::make_pair(Filename,
std::error_code(errno, std::generic_category()));
Buffers.push_back(std::move(MemberBufferOrErr.get()));
MemberRef = Buffers.back()->getMemBufferRef();
} else {
const object::Archive::Child &OldMember = Member.getOld();
assert((!Thin || OldMember.getParent()->isThin()) &&
"Thin archives cannot refers to member of other archives");
ErrorOr<MemoryBufferRef> MemberBufferOrErr =
OldMember.getMemoryBufferRef();
if (auto EC = MemberBufferOrErr.getError())
return std::make_pair("", EC);
MemberRef = MemberBufferOrErr.get();
}
Members.push_back(MemberRef);
}
unsigned MemberReferenceOffset = 0;
if (WriteSymtab) {
ErrorOr<unsigned> MemberReferenceOffsetOrErr = writeSymbolTable(
Out, Kind, NewMembers, Members, MemberOffsetRefs, Deterministic);
if (auto EC = MemberReferenceOffsetOrErr.getError())
return std::make_pair(ArcName, EC);
MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
}
std::vector<unsigned> StringMapIndexes;
if (Kind != object::Archive::K_BSD)
writeStringTable(Out, ArcName, NewMembers, StringMapIndexes, Thin);
unsigned MemberNum = 0;
unsigned NewMemberNum = 0;
std::vector<unsigned>::iterator StringMapIndexIter = StringMapIndexes.begin();
std::vector<unsigned> MemberOffset;
for (const NewArchiveIterator &I : NewMembers) {
MemoryBufferRef File = Members[MemberNum++];
unsigned Pos = Out.tell();
MemberOffset.push_back(Pos);
sys::TimeValue ModTime;
unsigned UID;
unsigned GID;
unsigned Perms;
if (Deterministic) {
ModTime.fromEpochTime(0);
UID = 0;
GID = 0;
Perms = 0644;
} else if (I.isNewMember()) {
const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum];
ModTime = Status.getLastModificationTime();
UID = Status.getUser();
GID = Status.getGroup();
Perms = Status.permissions();
} else {
const object::Archive::Child &OldMember = I.getOld();
ModTime = OldMember.getLastModified();
UID = OldMember.getUID();
GID = OldMember.getGID();
Perms = OldMember.getAccessMode();
}
if (I.isNewMember()) {
StringRef FileName = I.getNew();
const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum++];
printMemberHeader(Out, Kind, Thin, sys::path::filename(FileName),
StringMapIndexIter, ModTime, UID, GID, Perms,
Status.getSize());
} else {
const object::Archive::Child &OldMember = I.getOld();
ErrorOr<uint32_t> Size = OldMember.getSize();
if (std::error_code EC = Size.getError())
return std::make_pair("", EC);
printMemberHeader(Out, Kind, Thin, I.getName(), StringMapIndexIter,
ModTime, UID, GID, Perms, Size.get());
}
if (!Thin)
Out << File.getBuffer();
if (Out.tell() % 2)
Out << '\n';
}
if (MemberReferenceOffset) {
Out.seek(MemberReferenceOffset);
for (unsigned MemberNum : MemberOffsetRefs) {
if (Kind == object::Archive::K_BSD)
Out.seek(Out.tell() + 4); // skip over the string offset
print32(Out, Kind, MemberOffset[MemberNum]);
}
}
Output.keep();
Out.close();
sys::fs::rename(TmpArchive, ArcName);
return std::make_pair("", std::error_code());
}
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