Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix race on stopping monitor #1377

Merged
merged 2 commits into from
Dec 1, 2022
Merged

Fix race on stopping monitor #1377

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
47c6716
Fix race on stopping monitor
WardenGnaw Nov 29, 2022
699b18f
Add lock for stopping
WardenGnaw Dec 1, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
78 changes: 41 additions & 37 deletions src/DebugEngineHost/RegistryMonitor.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -47,14 +47,15 @@ private static extern int RegNotifyChangeKeyValue(SafeRegistryHandle hKey, bool

#endregion

private HostConfigurationSection _section;
private readonly HostConfigurationSection _section;
private readonly bool _watchSubtree;

// Set when registry value is changed
private AutoResetEvent m_changeEvent;

// Set when monitoring is stopped
private AutoResetEvent m_stoppedEvent;
private AutoResetEvent _stoppedEvent;

// Members to handle multiple stop calls.
private bool _isStopped = false;
private readonly object _stopLock = new object();

/// <summary>
/// Occurs when the specified registry key has changed.
Expand All @@ -80,9 +81,13 @@ public void Start()

public void Stop()
{
if (m_stoppedEvent != null)
lock (_stopLock)
{
m_stoppedEvent.Set();
if (!_isStopped)
{
_stoppedEvent?.Set();
_isStopped = true;
}
}
}

Expand All @@ -93,53 +98,52 @@ private void Monitor()
bool stopped = false;
try
{
m_stoppedEvent = new AutoResetEvent(false);
m_changeEvent = new AutoResetEvent(false);

IntPtr handle = m_changeEvent.SafeWaitHandle.DangerousGetHandle();

int errorCode = RegNotifyChangeKeyValue(_section.Handle, _watchSubtree, RegChangeNotifyFilter.REG_NOTIFY_CHANGE_NAME | RegChangeNotifyFilter.REG_NOTIFY_CHANGE_LAST_SET, handle, true);
if (errorCode != 0) // 0 is ERROR_SUCCESS
{
_nativsLogger?.WriteLine(LogLevel.Error, Resource.Error_WatchRegistry, errorCode);
}
else
_stoppedEvent = new AutoResetEvent(false);
using (AutoResetEvent registryChangedEvent = new AutoResetEvent(false))
{
while (!stopped)
{
int waitResult = WaitHandle.WaitAny(new WaitHandle[] { m_stoppedEvent, m_changeEvent });
IntPtr handle = registryChangedEvent.SafeWaitHandle.DangerousGetHandle();

if (waitResult == 0)
{
stopped = true;
}
else
int errorCode = RegNotifyChangeKeyValue(_section.Handle, _watchSubtree, RegChangeNotifyFilter.REG_NOTIFY_CHANGE_NAME | RegChangeNotifyFilter.REG_NOTIFY_CHANGE_LAST_SET, handle, true);
if (errorCode != 0) // 0 is ERROR_SUCCESS
{
_nativsLogger?.WriteLine(LogLevel.Error, Resource.Error_WatchRegistry, errorCode);
}
else
{
while (!stopped)
{
errorCode = RegNotifyChangeKeyValue(_section.Handle, _watchSubtree, RegChangeNotifyFilter.REG_NOTIFY_CHANGE_NAME | RegChangeNotifyFilter.REG_NOTIFY_CHANGE_LAST_SET, handle, true);
if (errorCode != 0) // 0 is ERROR_SUCCESS
int waitResult = WaitHandle.WaitAny(new WaitHandle[] { _stoppedEvent, registryChangedEvent });

if (waitResult == 0)
{
_nativsLogger?.WriteLine(LogLevel.Error, Resource.Error_WatchRegistry, errorCode);
break;
stopped = true;
}
else
{
errorCode = RegNotifyChangeKeyValue(_section.Handle, _watchSubtree, RegChangeNotifyFilter.REG_NOTIFY_CHANGE_NAME | RegChangeNotifyFilter.REG_NOTIFY_CHANGE_LAST_SET, handle, true);
if (errorCode != 0) // 0 is ERROR_SUCCESS
{
_nativsLogger?.WriteLine(LogLevel.Error, Resource.Error_WatchRegistry, errorCode);
break;
}
RegChanged?.Invoke(this, null);
}
RegChanged?.Invoke(this, null);
}
}
}
}
finally
{
_section.Dispose();
m_stoppedEvent?.Dispose();
m_changeEvent?.Dispose();
_stoppedEvent.Dispose();
_stoppedEvent = null;

m_stoppedEvent = null;
m_changeEvent = null;
_section.Dispose();
}
}

public void Dispose()
{
m_stoppedEvent?.Dispose();
Stop(); // Stopping the monitor will dispose of the AutoResetEvent and HostConfigurationSection
}
}
}