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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using Microsoft.Win32.SafeHandles;
using System.Runtime.InteropServices;
namespace System.IO
{
public partial class FileStream : Stream
{
private unsafe SafeFileHandle OpenHandle(FileMode mode, FileShare share, FileOptions options)
{
Interop.Kernel32.SECURITY_ATTRIBUTES secAttrs = GetSecAttrs(share);
int fAccess =
((_access & FileAccess.Read) == FileAccess.Read ? GENERIC_READ : 0) |
((_access & FileAccess.Write) == FileAccess.Write ? GENERIC_WRITE : 0);
// Our Inheritable bit was stolen from Windows, but should be set in
// the security attributes class. Don't leave this bit set.
share &= ~FileShare.Inheritable;
// Must use a valid Win32 constant here...
if (mode == FileMode.Append)
mode = FileMode.OpenOrCreate;
Interop.Kernel32.CREATEFILE2_EXTENDED_PARAMETERS parameters = new Interop.Kernel32.CREATEFILE2_EXTENDED_PARAMETERS();
parameters.dwSize = (uint)sizeof(Interop.Kernel32.CREATEFILE2_EXTENDED_PARAMETERS);
parameters.dwFileFlags = (uint)options;
parameters.lpSecurityAttributes = &secAttrs;
SafeFileHandle fileHandle = Interop.Kernel32.CreateFile2(
lpFileName: _path,
dwDesiredAccess: fAccess,
dwShareMode: share,
dwCreationDisposition: mode,
pCreateExParams: ¶meters);
fileHandle.IsAsync = _useAsyncIO;
if (fileHandle.IsInvalid)
{
// Return a meaningful exception with the full path.
// NT5 oddity - when trying to open "C:\" as a Win32FileStream,
// we usually get ERROR_PATH_NOT_FOUND from the OS. We should
// probably be consistent w/ every other directory.
int errorCode = Marshal.GetLastWin32Error();
if (errorCode == Interop.Errors.ERROR_PATH_NOT_FOUND && _path.Length == PathInternal.GetRootLength(_path))
errorCode = Interop.Errors.ERROR_ACCESS_DENIED;
throw Win32Marshal.GetExceptionForWin32Error(errorCode, $"{_path} {options} {fAccess} {share} {mode}");
}
return fileHandle;
}
#if PROJECTN
// TODO: These internal methods should be removed once we start consuming updated CoreFX builds
public static FileStream InternalOpen(string path, int bufferSize = 4096, bool useAsync = true)
{
return new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize, useAsync);
}
public static FileStream InternalCreate(string path, int bufferSize = 4096, bool useAsync = true)
{
return new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.Read, bufferSize, useAsync);
}
public static FileStream InternalAppend(string path, int bufferSize = 4096, bool useAsync = true)
{
return new FileStream(path, FileMode.Append, FileAccess.Write, FileShare.Read, bufferSize, useAsync);
}
#endif
}
}
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