mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-01 08:23:21 +01:00
f5736f87f2
the caller requested a null-terminated one. When mapping the file there could be a racing issue that resulted in the file being larger than the FileSize passed by the caller. We already have an assertion for this in MemoryBuffer::init() but have a runtime guarantee that the buffer will be null-terminated, so do a copy that adds a null-terminator. Protects against crash of rdar://11161822. llvm-svn: 154082
391 lines
14 KiB
C++
391 lines
14 KiB
C++
//===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the MemoryBuffer interface.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Support/MemoryBuffer.h"
|
|
#include "llvm/ADT/OwningPtr.h"
|
|
#include "llvm/ADT/SmallString.h"
|
|
#include "llvm/Config/config.h"
|
|
#include "llvm/Support/MathExtras.h"
|
|
#include "llvm/Support/Errno.h"
|
|
#include "llvm/Support/Path.h"
|
|
#include "llvm/Support/Process.h"
|
|
#include "llvm/Support/Program.h"
|
|
#include "llvm/Support/system_error.h"
|
|
#include <cassert>
|
|
#include <cstdio>
|
|
#include <cstring>
|
|
#include <cerrno>
|
|
#include <new>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#if !defined(_MSC_VER) && !defined(__MINGW32__)
|
|
#include <unistd.h>
|
|
#else
|
|
#include <io.h>
|
|
#endif
|
|
#include <fcntl.h>
|
|
using namespace llvm;
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// MemoryBuffer implementation itself.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
MemoryBuffer::~MemoryBuffer() { }
|
|
|
|
/// init - Initialize this MemoryBuffer as a reference to externally allocated
|
|
/// memory, memory that we know is already null terminated.
|
|
void MemoryBuffer::init(const char *BufStart, const char *BufEnd,
|
|
bool RequiresNullTerminator) {
|
|
assert((!RequiresNullTerminator || BufEnd[0] == 0) &&
|
|
"Buffer is not null terminated!");
|
|
BufferStart = BufStart;
|
|
BufferEnd = BufEnd;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// MemoryBufferMem implementation.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
/// CopyStringRef - Copies contents of a StringRef into a block of memory and
|
|
/// null-terminates it.
|
|
static void CopyStringRef(char *Memory, StringRef Data) {
|
|
memcpy(Memory, Data.data(), Data.size());
|
|
Memory[Data.size()] = 0; // Null terminate string.
|
|
}
|
|
|
|
/// GetNamedBuffer - Allocates a new MemoryBuffer with Name copied after it.
|
|
template <typename T>
|
|
static T *GetNamedBuffer(StringRef Buffer, StringRef Name,
|
|
bool RequiresNullTerminator) {
|
|
char *Mem = static_cast<char*>(operator new(sizeof(T) + Name.size() + 1));
|
|
CopyStringRef(Mem + sizeof(T), Name);
|
|
return new (Mem) T(Buffer, RequiresNullTerminator);
|
|
}
|
|
|
|
namespace {
|
|
/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory.
|
|
class MemoryBufferMem : public MemoryBuffer {
|
|
public:
|
|
MemoryBufferMem(StringRef InputData, bool RequiresNullTerminator) {
|
|
init(InputData.begin(), InputData.end(), RequiresNullTerminator);
|
|
}
|
|
|
|
virtual const char *getBufferIdentifier() const {
|
|
// The name is stored after the class itself.
|
|
return reinterpret_cast<const char*>(this + 1);
|
|
}
|
|
|
|
virtual BufferKind getBufferKind() const {
|
|
return MemoryBuffer_Malloc;
|
|
}
|
|
};
|
|
}
|
|
|
|
/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
|
|
/// that InputData must be a null terminated if RequiresNullTerminator is true!
|
|
MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
|
|
StringRef BufferName,
|
|
bool RequiresNullTerminator) {
|
|
return GetNamedBuffer<MemoryBufferMem>(InputData, BufferName,
|
|
RequiresNullTerminator);
|
|
}
|
|
|
|
/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
|
|
/// copying the contents and taking ownership of it. This has no requirements
|
|
/// on EndPtr[0].
|
|
MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData,
|
|
StringRef BufferName) {
|
|
MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName);
|
|
if (!Buf) return 0;
|
|
memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
|
|
InputData.size());
|
|
return Buf;
|
|
}
|
|
|
|
/// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
|
|
/// that is not initialized. Note that the caller should initialize the
|
|
/// memory allocated by this method. The memory is owned by the MemoryBuffer
|
|
/// object.
|
|
MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
|
|
StringRef BufferName) {
|
|
// Allocate space for the MemoryBuffer, the data and the name. It is important
|
|
// that MemoryBuffer and data are aligned so PointerIntPair works with them.
|
|
size_t AlignedStringLen =
|
|
RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.size() + 1,
|
|
sizeof(void*)); // TODO: Is sizeof(void*) enough?
|
|
size_t RealLen = AlignedStringLen + Size + 1;
|
|
char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow));
|
|
if (!Mem) return 0;
|
|
|
|
// The name is stored after the class itself.
|
|
CopyStringRef(Mem + sizeof(MemoryBufferMem), BufferName);
|
|
|
|
// The buffer begins after the name and must be aligned.
|
|
char *Buf = Mem + AlignedStringLen;
|
|
Buf[Size] = 0; // Null terminate buffer.
|
|
|
|
return new (Mem) MemoryBufferMem(StringRef(Buf, Size), true);
|
|
}
|
|
|
|
/// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
|
|
/// is completely initialized to zeros. Note that the caller should
|
|
/// initialize the memory allocated by this method. The memory is owned by
|
|
/// the MemoryBuffer object.
|
|
MemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
|
|
MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName);
|
|
if (!SB) return 0;
|
|
memset(const_cast<char*>(SB->getBufferStart()), 0, Size);
|
|
return SB;
|
|
}
|
|
|
|
|
|
/// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin
|
|
/// if the Filename is "-". If an error occurs, this returns null and fills
|
|
/// in *ErrStr with a reason. If stdin is empty, this API (unlike getSTDIN)
|
|
/// returns an empty buffer.
|
|
error_code MemoryBuffer::getFileOrSTDIN(StringRef Filename,
|
|
OwningPtr<MemoryBuffer> &result,
|
|
int64_t FileSize) {
|
|
if (Filename == "-")
|
|
return getSTDIN(result);
|
|
return getFile(Filename, result, FileSize);
|
|
}
|
|
|
|
error_code MemoryBuffer::getFileOrSTDIN(const char *Filename,
|
|
OwningPtr<MemoryBuffer> &result,
|
|
int64_t FileSize) {
|
|
if (strcmp(Filename, "-") == 0)
|
|
return getSTDIN(result);
|
|
return getFile(Filename, result, FileSize);
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// MemoryBuffer::getFile implementation.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
/// MemoryBufferMMapFile - This represents a file that was mapped in with the
|
|
/// sys::Path::MapInFilePages method. When destroyed, it calls the
|
|
/// sys::Path::UnMapFilePages method.
|
|
class MemoryBufferMMapFile : public MemoryBufferMem {
|
|
public:
|
|
MemoryBufferMMapFile(StringRef Buffer, bool RequiresNullTerminator)
|
|
: MemoryBufferMem(Buffer, RequiresNullTerminator) { }
|
|
|
|
~MemoryBufferMMapFile() {
|
|
static int PageSize = sys::Process::GetPageSize();
|
|
|
|
uintptr_t Start = reinterpret_cast<uintptr_t>(getBufferStart());
|
|
size_t Size = getBufferSize();
|
|
uintptr_t RealStart = Start & ~(PageSize - 1);
|
|
size_t RealSize = Size + (Start - RealStart);
|
|
|
|
sys::Path::UnMapFilePages(reinterpret_cast<const char*>(RealStart),
|
|
RealSize);
|
|
}
|
|
|
|
virtual BufferKind getBufferKind() const {
|
|
return MemoryBuffer_MMap;
|
|
}
|
|
};
|
|
}
|
|
|
|
error_code MemoryBuffer::getFile(StringRef Filename,
|
|
OwningPtr<MemoryBuffer> &result,
|
|
int64_t FileSize,
|
|
bool RequiresNullTerminator) {
|
|
// Ensure the path is null terminated.
|
|
SmallString<256> PathBuf(Filename.begin(), Filename.end());
|
|
return MemoryBuffer::getFile(PathBuf.c_str(), result, FileSize,
|
|
RequiresNullTerminator);
|
|
}
|
|
|
|
error_code MemoryBuffer::getFile(const char *Filename,
|
|
OwningPtr<MemoryBuffer> &result,
|
|
int64_t FileSize,
|
|
bool RequiresNullTerminator) {
|
|
int OpenFlags = O_RDONLY;
|
|
#ifdef O_BINARY
|
|
OpenFlags |= O_BINARY; // Open input file in binary mode on win32.
|
|
#endif
|
|
int FD = ::open(Filename, OpenFlags);
|
|
if (FD == -1)
|
|
return error_code(errno, posix_category());
|
|
|
|
error_code ret = getOpenFile(FD, Filename, result, FileSize, FileSize,
|
|
0, RequiresNullTerminator);
|
|
close(FD);
|
|
return ret;
|
|
}
|
|
|
|
static bool shouldUseMmap(int FD,
|
|
size_t FileSize,
|
|
size_t MapSize,
|
|
off_t Offset,
|
|
bool RequiresNullTerminator,
|
|
int PageSize) {
|
|
// We don't use mmap for small files because this can severely fragment our
|
|
// address space.
|
|
if (MapSize < 4096*4)
|
|
return false;
|
|
|
|
if (!RequiresNullTerminator)
|
|
return true;
|
|
|
|
|
|
// If we don't know the file size, use fstat to find out. fstat on an open
|
|
// file descriptor is cheaper than stat on a random path.
|
|
// FIXME: this chunk of code is duplicated, but it avoids a fstat when
|
|
// RequiresNullTerminator = false and MapSize != -1.
|
|
if (FileSize == size_t(-1)) {
|
|
struct stat FileInfo;
|
|
// TODO: This should use fstat64 when available.
|
|
if (fstat(FD, &FileInfo) == -1) {
|
|
return error_code(errno, posix_category());
|
|
}
|
|
FileSize = FileInfo.st_size;
|
|
}
|
|
|
|
// If we need a null terminator and the end of the map is inside the file,
|
|
// we cannot use mmap.
|
|
size_t End = Offset + MapSize;
|
|
assert(End <= FileSize);
|
|
if (End != FileSize)
|
|
return false;
|
|
|
|
// Don't try to map files that are exactly a multiple of the system page size
|
|
// if we need a null terminator.
|
|
if ((FileSize & (PageSize -1)) == 0)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
|
|
OwningPtr<MemoryBuffer> &result,
|
|
uint64_t FileSize, uint64_t MapSize,
|
|
int64_t Offset,
|
|
bool RequiresNullTerminator) {
|
|
static int PageSize = sys::Process::GetPageSize();
|
|
|
|
// Default is to map the full file.
|
|
if (MapSize == uint64_t(-1)) {
|
|
// If we don't know the file size, use fstat to find out. fstat on an open
|
|
// file descriptor is cheaper than stat on a random path.
|
|
if (FileSize == uint64_t(-1)) {
|
|
struct stat FileInfo;
|
|
// TODO: This should use fstat64 when available.
|
|
if (fstat(FD, &FileInfo) == -1) {
|
|
return error_code(errno, posix_category());
|
|
}
|
|
FileSize = FileInfo.st_size;
|
|
}
|
|
MapSize = FileSize;
|
|
}
|
|
|
|
if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator,
|
|
PageSize)) {
|
|
off_t RealMapOffset = Offset & ~(PageSize - 1);
|
|
off_t Delta = Offset - RealMapOffset;
|
|
size_t RealMapSize = MapSize + Delta;
|
|
|
|
if (const char *Pages = sys::Path::MapInFilePages(FD,
|
|
RealMapSize,
|
|
RealMapOffset)) {
|
|
result.reset(GetNamedBuffer<MemoryBufferMMapFile>(
|
|
StringRef(Pages + Delta, MapSize), Filename, RequiresNullTerminator));
|
|
|
|
if (RequiresNullTerminator && result->getBufferEnd()[0] != '\0') {
|
|
// There could be a racing issue that resulted in the file being larger
|
|
// than the FileSize passed by the caller. We already have an assertion
|
|
// for this in MemoryBuffer::init() but have a runtime guarantee that
|
|
// the buffer will be null-terminated here, so do a copy that adds a
|
|
// null-terminator.
|
|
result.reset(MemoryBuffer::getMemBufferCopy(result->getBuffer(),
|
|
Filename));
|
|
}
|
|
return error_code::success();
|
|
}
|
|
}
|
|
|
|
MemoryBuffer *Buf = MemoryBuffer::getNewUninitMemBuffer(MapSize, Filename);
|
|
if (!Buf) {
|
|
// Failed to create a buffer. The only way it can fail is if
|
|
// new(std::nothrow) returns 0.
|
|
return make_error_code(errc::not_enough_memory);
|
|
}
|
|
|
|
OwningPtr<MemoryBuffer> SB(Buf);
|
|
char *BufPtr = const_cast<char*>(SB->getBufferStart());
|
|
|
|
size_t BytesLeft = MapSize;
|
|
#ifndef HAVE_PREAD
|
|
if (lseek(FD, Offset, SEEK_SET) == -1)
|
|
return error_code(errno, posix_category());
|
|
#endif
|
|
|
|
while (BytesLeft) {
|
|
#ifdef HAVE_PREAD
|
|
ssize_t NumRead = ::pread(FD, BufPtr, BytesLeft, MapSize-BytesLeft+Offset);
|
|
#else
|
|
ssize_t NumRead = ::read(FD, BufPtr, BytesLeft);
|
|
#endif
|
|
if (NumRead == -1) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
// Error while reading.
|
|
return error_code(errno, posix_category());
|
|
}
|
|
if (NumRead == 0) {
|
|
assert(0 && "We got inaccurate FileSize value or fstat reported an "
|
|
"invalid file size.");
|
|
*BufPtr = '\0'; // null-terminate at the actual size.
|
|
break;
|
|
}
|
|
BytesLeft -= NumRead;
|
|
BufPtr += NumRead;
|
|
}
|
|
|
|
result.swap(SB);
|
|
return error_code::success();
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// MemoryBuffer::getSTDIN implementation.
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
error_code MemoryBuffer::getSTDIN(OwningPtr<MemoryBuffer> &result) {
|
|
// Read in all of the data from stdin, we cannot mmap stdin.
|
|
//
|
|
// FIXME: That isn't necessarily true, we should try to mmap stdin and
|
|
// fallback if it fails.
|
|
sys::Program::ChangeStdinToBinary();
|
|
|
|
const ssize_t ChunkSize = 4096*4;
|
|
SmallString<ChunkSize> Buffer;
|
|
ssize_t ReadBytes;
|
|
// Read into Buffer until we hit EOF.
|
|
do {
|
|
Buffer.reserve(Buffer.size() + ChunkSize);
|
|
ReadBytes = read(0, Buffer.end(), ChunkSize);
|
|
if (ReadBytes == -1) {
|
|
if (errno == EINTR) continue;
|
|
return error_code(errno, posix_category());
|
|
}
|
|
Buffer.set_size(Buffer.size() + ReadBytes);
|
|
} while (ReadBytes != 0);
|
|
|
|
result.reset(getMemBufferCopy(Buffer, "<stdin>"));
|
|
return error_code::success();
|
|
}
|