Make sure error logging or destructors don't throw exception when trying to get file name from handle (#393)

- Bugfix: Make sure error logging or destructors don't throw exception when trying to get file name from handle

3 files changed, 58 insertions, 20 deletions

diff --git a/src/zencore/filesystem.cpp b/src/zencore/filesystem.cpp
index 8abe5af00..b1ec14a37 100644
--- a/src/zencore/filesystem.cpp
+++ b/src/zencore/filesystem.cpp
@@ -1063,19 +1063,25 @@ FileSystemTraversal::TraverseFileSystem(const std::filesystem::path& RootDir, Tr
 	closedir(Dir);
 #endif	// ZEN_PLATFORM_WINDOWS
 }
-
 std::filesystem::path
-PathFromHandle(void* NativeHandle)
+PathFromHandle(void* NativeHandle, std::error_code& Ec)
 {
+	if (NativeHandle == nullptr)
+	{
+		return std::filesystem::path();
+	}
 #if ZEN_PLATFORM_WINDOWS
-	if (NativeHandle == nullptr || NativeHandle == INVALID_HANDLE_VALUE)
+	if (NativeHandle == INVALID_HANDLE_VALUE)
 	{
 		return std::filesystem::path();
 	}
 
-	auto GetFinalPathNameByHandleWRetry = [](HANDLE hFile, LPWSTR lpszFilePath, DWORD cchFilePath, DWORD dwFlags) -> DWORD {
-		while (true)
+	auto GetFinalPathNameByHandleWRetry =
+		[&Ec](HANDLE hFile, LPWSTR lpszFilePath, DWORD cchFilePath, DWORD dwFlags, DWORD& OutRequiredLength) -> DWORD {
+		size_t MaxTries = 5;
+		while (MaxTries > 0)
 		{
+			MaxTries--;
 			DWORD Res = GetFinalPathNameByHandleW(hFile, lpszFilePath, cchFilePath, dwFlags);
 			if (Res == 0)
 			{
@@ -1084,22 +1090,27 @@ PathFromHandle(void* NativeHandle)
 				// Retry if that is the case.
 				if (LastError != ERROR_ACCESS_DENIED)
 				{
-					ThrowSystemError(LastError, fmt::format("failed to get path from file handle {}", hFile));
+					Sleep(2);
+					return LastError;
 				}
 				// Retry
 				continue;
 			}
 			ZEN_ASSERT(Res != 1);  // We don't accept empty path names
-			return Res;
+			OutRequiredLength = Res;
+			return ERROR_SUCCESS;
 		}
+		return ERROR_ACCESS_DENIED;
 	};
 
 	static const DWORD PathDataSize = 512;
 	wchar_t			   PathData[PathDataSize];
-	DWORD			   RequiredLengthIncludingNul = GetFinalPathNameByHandleWRetry(NativeHandle, PathData, PathDataSize, FILE_NAME_OPENED);
-	if (RequiredLengthIncludingNul == 0)
+	DWORD			   RequiredLengthIncludingNul = 0;
+	DWORD Error = GetFinalPathNameByHandleWRetry(NativeHandle, PathData, PathDataSize, FILE_NAME_OPENED, RequiredLengthIncludingNul);
+	if (Error != ERROR_SUCCESS)
 	{
-		ThrowLastError(fmt::format("failed to get path from file handle {}", NativeHandle));
+		Ec = MakeErrorCodeFromLastError();
+		return std::filesystem::path();
 	}
 
 	if (RequiredLengthIncludingNul < PathDataSize)
@@ -1111,7 +1122,13 @@ PathFromHandle(void* NativeHandle)
 	std::wstring FullPath;
 	FullPath.resize(RequiredLengthIncludingNul - 1);
 
-	const DWORD FinalLength = GetFinalPathNameByHandleWRetry(NativeHandle, FullPath.data(), RequiredLengthIncludingNul, FILE_NAME_OPENED);
+	DWORD FinalLength = 0;
+	Error = GetFinalPathNameByHandleWRetry(NativeHandle, FullPath.data(), RequiredLengthIncludingNul, FILE_NAME_OPENED, FinalLength);
+	if (Error != ERROR_SUCCESS)
+	{
+		Ec = MakeErrorCodeFromLastError();
+		return std::filesystem::path();
+	}
 	ZEN_UNUSED(FinalLength);
 	return FullPath;
 
@@ -1123,7 +1140,8 @@ PathFromHandle(void* NativeHandle)
 	ssize_t BytesRead = readlink(Path, Link, sizeof(Link) - 1);
 	if (BytesRead <= 0)
 	{
-		return std::filesystem::path();
+		Ec = MakeErrorCodeFromLastError();
+		return {};
 	}
 
 	Link[BytesRead] = '\0';
@@ -1133,13 +1151,26 @@ PathFromHandle(void* NativeHandle)
 	char Path[MAXPATHLEN];
 	if (fcntl(Fd, F_GETPATH, Path) < 0)
 	{
-		return std::filesystem::path();
+		Ec = MakeErrorCodeFromLastError();
+		return {};
 	}
 
 	return Path;
 #endif	// ZEN_PLATFORM_WINDOWS
 }
 
+std::filesystem::path
+PathFromHandle(void* NativeHandle)
+{
+	std::error_code		  Ec;
+	std::filesystem::path Result = PathFromHandle(NativeHandle, Ec);
+	if (Ec)
+	{
+		throw std::system_error(Ec, fmt::format("failed to get path from file handle '{}'", NativeHandle));
+	}
+	return Result;
+}
+
 uint64_t
 FileSizeFromHandle(void* NativeHandle)
 {
diff --git a/src/zencore/include/zencore/filesystem.h b/src/zencore/include/zencore/filesystem.h
index 37a562664..a78edd16b 100644
--- a/src/zencore/include/zencore/filesystem.h
+++ b/src/zencore/include/zencore/filesystem.h
@@ -34,6 +34,10 @@ ZENCORE_API bool CleanDirectory(const std::filesystem::path& dir);
  */
 ZENCORE_API std::filesystem::path PathFromHandle(void* NativeHandle);
 
+/** Map native file handle to a path
+ */
+ZENCORE_API std::filesystem::path PathFromHandle(void* NativeHandle, std::error_code& Ec);
+
 /** Query file size from native file handle
  */
 ZENCORE_API uint64_t FileSizeFromHandle(void* NativeHandle);
diff --git a/src/zencore/iobuffer.cpp b/src/zencore/iobuffer.cpp
index efec06f7f..73600a09e 100644
--- a/src/zencore/iobuffer.cpp
+++ b/src/zencore/iobuffer.cpp
@@ -332,17 +332,18 @@ IoBufferExtendedCore::Materialize() const
 #endif	// ZEN_PLATFORM_WINDOWS
 		if (Error || (BytesRead != m_DataBytes))
 		{
+			std::error_code DummyEc;
 			ZEN_ERROR("ReadFile/pread failed (offset {:#x}, size {:#x}) file: '{}' (size {:#x}), {}",
 					  m_FileOffset,
 					  m_DataBytes,
-					  zen::PathFromHandle(m_FileHandle),
+					  zen::PathFromHandle(m_FileHandle, DummyEc),
 					  zen::FileSizeFromHandle(m_FileHandle),
 					  GetSystemErrorAsString(Error));
 			throw std::system_error(std::error_code(Error, std::system_category()),
 									fmt::format("ReadFile/pread failed (offset {:#x}, size {:#x}) file: '{}' (size {:#x})",
 												m_FileOffset,
 												m_DataBytes,
-												PathFromHandle(m_FileHandle),
+												PathFromHandle(m_FileHandle, DummyEc),
 												FileSizeFromHandle(m_FileHandle)));
 		}
 
@@ -368,10 +369,11 @@ IoBufferExtendedCore::Materialize() const
 
 	if (NewMmapHandle == nullptr)
 	{
-		int32_t Error = zen::GetLastError();
-		ZEN_ERROR("CreateFileMapping failed on file '{}', {}", zen::PathFromHandle(m_FileHandle), GetSystemErrorAsString(Error));
+		int32_t			Error = zen::GetLastError();
+		std::error_code DummyEc;
+		ZEN_ERROR("CreateFileMapping failed on file '{}', {}", zen::PathFromHandle(m_FileHandle, DummyEc), GetSystemErrorAsString(Error));
 		throw std::system_error(std::error_code(Error, std::system_category()),
-								fmt::format("CreateFileMapping failed on file '{}'", zen::PathFromHandle(m_FileHandle)));
+								fmt::format("CreateFileMapping failed on file '{}'", zen::PathFromHandle(m_FileHandle, DummyEc)));
 	}
 
 	NewFlags |= kOwnsMmap;
@@ -401,17 +403,18 @@ IoBufferExtendedCore::Materialize() const
 		CloseHandle(NewMmapHandle);
 #endif	// ZEN_PLATFORM_WINDOWS
 
+		std::error_code DummyEc;
 		ZEN_ERROR("MapViewOfFile/mmap failed (offset {:#x}, size {:#x}) file: '{}' (size {:#x}), {}",
 				  MapOffset,
 				  MapSize,
-				  zen::PathFromHandle(m_FileHandle),
+				  zen::PathFromHandle(m_FileHandle, DummyEc),
 				  zen::FileSizeFromHandle(m_FileHandle),
 				  GetSystemErrorAsString(Error));
 		throw std::system_error(std::error_code(Error, std::system_category()),
 								fmt::format("MapViewOfFile failed (offset {:#x}, size {:#x}) file: '{}' (size {:#x})",
 											MapOffset,
 											MapSize,
-											zen::PathFromHandle(m_FileHandle),
+											zen::PathFromHandle(m_FileHandle, DummyEc),
 											zen::FileSizeFromHandle(m_FileHandle)));
 	}