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//------------------------------------------------------------------------------
// <copyright file="UnsafeMethods.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Net
{
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.Win32.SafeHandles;
using System.Security;
using System.Runtime.InteropServices;
using System.Runtime.ConstrainedExecution;
using System.Threading;
using System.Net.Sockets;
[Flags]
internal enum FormatMessageFlags : uint
{
FORMAT_MESSAGE_ALLOCATE_BUFFER = 0x00000100,
//FORMAT_MESSAGE_IGNORE_INSERTS = 0x00000200,
//FORMAT_MESSAGE_FROM_STRING = 0x00000400,
FORMAT_MESSAGE_FROM_HMODULE = 0x00000800,
FORMAT_MESSAGE_FROM_SYSTEM = 0x00001000,
FORMAT_MESSAGE_ARGUMENT_ARRAY = 0x00002000
}
[System.Security.SuppressUnmanagedCodeSecurityAttribute()]
internal static class UnsafeSystemNativeMethods
{
private const string KERNEL32 = "KERNEL32.dll";
[System.Security.SecurityCritical]
[DllImport(KERNEL32, ExactSpelling = true, CharSet = CharSet.Unicode, SetLastError = true)]
internal static extern unsafe SafeLoadLibrary LoadLibraryExW( string lpwLibFileName, [In] void* hFile, uint dwFlags);
[DllImport(KERNEL32, ExactSpelling = true, SetLastError = true)]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern unsafe bool FreeLibrary(IntPtr hModule);
[System.Security.SecurityCritical]
[DllImport(KERNEL32, EntryPoint = "GetProcAddress", SetLastError = true, BestFitMapping = false)]
internal extern static IntPtr GetProcAddress(SafeLoadLibrary hModule, string entryPoint);
[DllImport(KERNEL32, CharSet = CharSet.Unicode)]
internal extern static uint FormatMessage(
FormatMessageFlags dwFlags,
IntPtr lpSource,
UInt32 dwMessageId,
UInt32 dwLanguageId,
ref IntPtr lpBuffer,
UInt32 nSize,
IntPtr vaArguments
);
[DllImport(KERNEL32, CharSet = CharSet.Unicode)]
internal extern static uint LocalFree(IntPtr lpMem);
}
// <SecurityKernel Critical="True" Ring="0">
// <SatisfiesLinkDemand Name="SafeHandleZeroOrMinusOneIsInvalid" />
// </SecurityKernel>
#pragma warning disable 618 // Have not migrated to v4 transparency yet
[System.Security.SecurityCritical(System.Security.SecurityCriticalScope.Everything)]
#pragma warning restore 618
[System.Security.SuppressUnmanagedCodeSecurityAttribute()]
internal sealed class SafeLoadLibrary : SafeHandleZeroOrMinusOneIsInvalid
{
private const string KERNEL32 = "kernel32.dll";
private SafeLoadLibrary() : base(true) { }
//private SafeLoadLibrary(bool ownsHandle) : base(ownsHandle) { }
//internal static readonly SafeLoadLibrary Zero = new SafeLoadLibrary(false);
internal unsafe static SafeLoadLibrary LoadLibraryEx(string library) {
SafeLoadLibrary result = UnsafeSystemNativeMethods.LoadLibraryExW(library, null, 0);
if (result.IsInvalid) {
//NOTE:
//IsInvalid tests the numeric value of the handle.
//SetHandleAsInvalid sets the handle as closed, so that further closing
//does not have to take place in the critical finalizer thread.
//
//You would think that when you assign 0 or -1 to an instance of
//SafeHandleZeroOrMinusoneIsInvalid, the handle will not be closed, since after all it is invalid
//It turns out that the SafeHandleZetoOrMinusOneIsInvalid overrides only the IsInvalid() method
//It does not do anything to automatically close it.
//So we have to SetHandleAsInvalid --> Which means mark it closed -- so that
//we will not eventually call CloseHandle on 0 or -1
result.SetHandleAsInvalid();
}
return result;
}
protected override bool ReleaseHandle() {
return UnsafeSystemNativeMethods.FreeLibrary(handle);
}
}
}
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