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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef MmapFaultHandler_h_
#define MmapFaultHandler_h_
#if defined(XP_WIN)
// Windows
# ifdef HAVE_SEH_EXCEPTIONS
# define MMAP_FAULT_HANDLER_BEGIN_HANDLE(fd) __try {
# define MMAP_FAULT_HANDLER_BEGIN_BUFFER(buf, bufLen) __try {
# define MMAP_FAULT_HANDLER_CATCH(retval) \
} \
__except (GetExceptionCode() == EXCEPTION_IN_PAGE_ERROR \
? EXCEPTION_EXECUTE_HANDLER \
: EXCEPTION_CONTINUE_SEARCH) { \
NS_WARNING("unexpected EXCEPTION_IN_PAGE_ERROR"); \
return retval; \
}
# else
# define MMAP_FAULT_HANDLER_BEGIN_HANDLE(fd) {
# define MMAP_FAULT_HANDLER_BEGIN_BUFFER(buf, bufLen) {
# define MMAP_FAULT_HANDLER_CATCH(retval) }
# endif
#elif defined(XP_DARWIN)
// MacOS
# define MMAP_FAULT_HANDLER_BEGIN_HANDLE(fd) {
# define MMAP_FAULT_HANDLER_BEGIN_BUFFER(buf, bufLen) {
# define MMAP_FAULT_HANDLER_CATCH(retval) }
#elif defined(__wasi__)
# define MMAP_FAULT_HANDLER_BEGIN_HANDLE(fd) {
# define MMAP_FAULT_HANDLER_BEGIN_BUFFER(buf, bufLen) {
# define MMAP_FAULT_HANDLER_CATCH(retval) }
#else
// Linux
# include "mozilla/Attributes.h"
# include "mozilla/Types.h"
# include <stdint.h>
# include <setjmp.h>
class MOZ_RAII MmapAccessScope {
public:
MFBT_API MmapAccessScope(void* aBuf, uint32_t aBufLen,
const char* aFilename = nullptr);
MFBT_API ~MmapAccessScope();
MmapAccessScope(const MmapAccessScope&) = delete;
MmapAccessScope& operator=(const MmapAccessScope&) = delete;
void SetThreadLocalScope();
bool IsInsideBuffer(void* aPtr);
void CrashWithInfo(void* aPtr);
// sigsetjmp cannot be called from a method that returns before calling
// siglongjmp, so the macro must call sigsetjmp directly and mJmpBuf must be
// public.
sigjmp_buf mJmpBuf;
private:
void* mBuf;
const char* mFilename;
uint32_t mBufLen;
MmapAccessScope* mPreviousScope;
};
// Gets around warnings for null-checking in a macro.
template <typename T>
inline bool ValidFD(T fd) {
return !!fd;
}
# define MMAP_FAULT_HANDLER_BEGIN_HANDLE(fd) \
{ \
void* mmapScopeBuf = nullptr; \
nsCString mmapScopeFilename; \
uint32_t mmapScopeBufLen = 0; \
if (ValidFD(fd) && fd->mMap) { \
mmapScopeBuf = (void*)fd->mFileStart; \
mmapScopeBufLen = fd->mTotalLen; \
} \
if (ValidFD(fd) && fd->mFile) { \
nsCOMPtr<nsIFile> file = fd->mFile.GetBaseFile(); \
if (file) { \
file->GetNativeLeafName(mmapScopeFilename); \
} \
} \
MmapAccessScope mmapScope(mmapScopeBuf, mmapScopeBufLen, \
mmapScopeFilename.get()); \
if (sigsetjmp(mmapScope.mJmpBuf, 0) == 0) {
# define MMAP_FAULT_HANDLER_BEGIN_BUFFER(buf, bufLen) \
{ \
MmapAccessScope mmapScope((void*)(buf), (bufLen)); \
if (sigsetjmp(mmapScope.mJmpBuf, 0) == 0) {
# define MMAP_FAULT_HANDLER_CATCH(retval) \
} \
else { \
NS_WARNING("SIGBUS received when accessing mmapped file"); \
return retval; \
} \
}
#endif
#endif
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