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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.
using System.IO;
using System.Runtime.InteropServices;
using Microsoft.Win32.SafeHandles;
namespace System.Threading
{
public partial class EventWaitHandle
{
private const uint AccessRights = (uint)Interop.Kernel32.MAXIMUM_ALLOWED | Interop.Kernel32.SYNCHRONIZE | Interop.Kernel32.EVENT_MODIFY_STATE;
#if TARGET_WINDOWS
// Can't use MAXIMUM_ALLOWED in an access control entry (ACE)
private const int CurrentUserOnlyAceRights =
Interop.Kernel32.STANDARD_RIGHTS_REQUIRED | Interop.Kernel32.SYNCHRONIZE | Interop.Kernel32.EVENT_MODIFY_STATE;
#endif
private EventWaitHandle(SafeWaitHandle handle)
{
SafeWaitHandle = handle;
}
private void CreateEventCore(bool initialState, EventResetMode mode)
{
ValidateMode(mode);
uint flags = initialState ? Interop.Kernel32.CREATE_EVENT_INITIAL_SET : 0;
if (mode == EventResetMode.ManualReset)
flags |= Interop.Kernel32.CREATE_EVENT_MANUAL_RESET;
SafeWaitHandle handle = Interop.Kernel32.CreateEventEx(lpSecurityAttributes: 0, name: null, flags, AccessRights);
if (handle.IsInvalid)
{
int errorCode = Marshal.GetLastPInvokeError();
handle.SetHandleAsInvalid();
throw Win32Marshal.GetExceptionForWin32Error(errorCode);
}
SafeWaitHandle = handle;
}
private unsafe void CreateEventCore(
bool initialState,
EventResetMode mode,
string? name,
NamedWaitHandleOptionsInternal options,
out bool createdNew)
{
ValidateMode(mode);
#if !TARGET_WINDOWS
if (name != null)
{
throw new PlatformNotSupportedException(SR.PlatformNotSupported_NamedSynchronizationPrimitives);
}
#endif
void* securityAttributesPtr = null;
SafeWaitHandle handle;
int errorCode;
#if TARGET_WINDOWS
Thread.CurrentUserSecurityDescriptorInfo securityDescriptorInfo = default;
Interop.Kernel32.SECURITY_ATTRIBUTES securityAttributes = default;
if (!string.IsNullOrEmpty(name) && options.WasSpecified)
{
name = options.GetNameWithSessionPrefix(name);
if (options.CurrentUserOnly)
{
securityDescriptorInfo = new(CurrentUserOnlyAceRights);
securityAttributes.nLength = (uint)sizeof(Interop.Kernel32.SECURITY_ATTRIBUTES);
securityAttributes.lpSecurityDescriptor = (void*)securityDescriptorInfo.SecurityDescriptor;
securityAttributesPtr = &securityAttributes;
}
}
using (securityDescriptorInfo)
{
#endif
uint eventFlags = initialState ? Interop.Kernel32.CREATE_EVENT_INITIAL_SET : 0;
if (mode == EventResetMode.ManualReset)
eventFlags |= Interop.Kernel32.CREATE_EVENT_MANUAL_RESET;
handle = Interop.Kernel32.CreateEventEx((nint)securityAttributesPtr, name, eventFlags, AccessRights);
errorCode = Marshal.GetLastPInvokeError();
if (handle.IsInvalid)
{
handle.SetHandleAsInvalid();
if (!string.IsNullOrEmpty(name) && errorCode == Interop.Errors.ERROR_INVALID_HANDLE)
throw new WaitHandleCannotBeOpenedException(SR.Format(SR.Threading_WaitHandleCannotBeOpenedException_InvalidHandle, name));
throw Win32Marshal.GetExceptionForWin32Error(errorCode, name);
}
#if TARGET_WINDOWS
if (errorCode == Interop.Errors.ERROR_ALREADY_EXISTS && securityAttributesPtr != null)
{
try
{
if (!Thread.CurrentUserSecurityDescriptorInfo.IsSecurityDescriptorCompatible(
securityDescriptorInfo.TokenUser,
handle,
Interop.Kernel32.EVENT_MODIFY_STATE))
{
throw new WaitHandleCannotBeOpenedException(SR.Format(SR.NamedWaitHandles_ExistingObjectIncompatibleWithCurrentUserOnly, name));
}
}
catch
{
handle.Dispose();
throw;
}
}
}
#endif
createdNew = errorCode != Interop.Errors.ERROR_ALREADY_EXISTS;
SafeWaitHandle = handle;
}
private static OpenExistingResult OpenExistingWorker(
string name,
NamedWaitHandleOptionsInternal options,
out EventWaitHandle? result)
{
#if TARGET_WINDOWS
ArgumentException.ThrowIfNullOrEmpty(name);
if (options.WasSpecified)
{
name = options.GetNameWithSessionPrefix(name);
}
SafeWaitHandle myHandle = Interop.Kernel32.OpenEvent(AccessRights, false, name);
if (myHandle.IsInvalid)
{
result = null;
int errorCode = Marshal.GetLastPInvokeError();
myHandle.Dispose();
if (errorCode == Interop.Errors.ERROR_FILE_NOT_FOUND || errorCode == Interop.Errors.ERROR_INVALID_NAME)
return OpenExistingResult.NameNotFound;
if (errorCode == Interop.Errors.ERROR_PATH_NOT_FOUND)
return OpenExistingResult.PathNotFound;
if (errorCode == Interop.Errors.ERROR_INVALID_HANDLE)
return OpenExistingResult.NameInvalid;
throw Win32Marshal.GetExceptionForWin32Error(errorCode, name);
}
if (options.WasSpecified && options.CurrentUserOnly)
{
try
{
if (!Thread.CurrentUserSecurityDescriptorInfo.IsValidSecurityDescriptor(
myHandle,
Interop.Kernel32.EVENT_MODIFY_STATE))
{
myHandle.Dispose();
result = null;
return OpenExistingResult.ObjectIncompatibleWithCurrentUserOnly;
}
}
catch
{
myHandle.Dispose();
throw;
}
}
result = new EventWaitHandle(myHandle);
return OpenExistingResult.Success;
#else
throw new PlatformNotSupportedException(SR.PlatformNotSupported_NamedSynchronizationPrimitives);
#endif
}
public bool Reset()
{
bool res = Interop.Kernel32.ResetEvent(SafeWaitHandle);
if (!res)
throw Win32Marshal.GetExceptionForLastWin32Error();
return res;
}
public bool Set()
{
bool res = Interop.Kernel32.SetEvent(SafeWaitHandle);
if (!res)
throw Win32Marshal.GetExceptionForLastWin32Error();
return res;
}
internal static bool Set(SafeWaitHandle waitHandle)
{
return Interop.Kernel32.SetEvent(waitHandle);
}
}
}
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