internal ProcessWaitHandle(ProcessWaitState processWaitState)
{
// Get the wait state's event, and use that event's safe wait handle
// in place of ours. This will let code register for completion notifications
// on this ProcessWaitHandle and be notified when the wait state's handle completes.
ManualResetEvent mre = processWaitState.EnsureExitedEvent();
this.SetSafeWaitHandle(mre.GetSafeWaitHandle());
}
public void Dispose()
{
if (_state != null)
{
GC.SuppressFinalize(this);
_state.ReleaseRef();
_state = null;
}
}
/// <summary>
/// Ensures that the mapping table contains an entry for the process ID,
/// increments its ref count, and returns it.
/// </summary>
/// <param name="processId">The process ID for which we need wait state.</param>
/// <returns>The wait state object.</returns>
internal static ProcessWaitState AddRef(int processId, bool isNewChild, bool usesTerminal)
{
lock (s_childProcessWaitStates)
{
ProcessWaitState pws;
if (isNewChild)
{
// When the PID is recycled for a new child, we remove the old child.
s_childProcessWaitStates.Remove(processId);
pws = new ProcessWaitState(processId, isChild: true, usesTerminal);
s_childProcessWaitStates.Add(processId, pws);
pws._outstandingRefCount++; // For Holder
pws._outstandingRefCount++; // Decremented in CheckChildren
}
else
{
lock (s_processWaitStates)
{
DateTime exitTime = default;
// We are referencing an existing process.
// This may be a child process, so we check s_childProcessWaitStates too.
if (s_childProcessWaitStates.TryGetValue(processId, out pws))
{
// child process
}
else if (s_processWaitStates.TryGetValue(processId, out pws))
{
// This is best effort for dealing with recycled pids for non-child processes.
// As long as we haven't observed process exit, it's safe to share the ProcessWaitState.
// Once we've observed the exit, we'll create a new ProcessWaitState just in case
// this may be a recycled pid.
// If it wasn't, that ProcessWaitState will observe too that the process has exited.
// We pass the ExitTime so it can be the same, but we'll clear it when we see there
// is a live process with that pid.
if (pws.GetExited(out _, refresh: false))
{
s_processWaitStates.Remove(processId);
exitTime = pws.ExitTime;
pws = null;
}
}
if (pws == null)
{
pws = new ProcessWaitState(processId, isChild: false, usesTerminal: false, exitTime);
s_processWaitStates.Add(processId, pws);
}
pws._outstandingRefCount++;
}
}
return(pws);
}
}
private static void OnSigChild(bool reapAll)
{
// Lock to avoid races with Process.Start
s_processStartLock.EnterWriteLock();
try
{
ProcessWaitState.CheckChildren(reapAll);
}
finally
{
s_processStartLock.ExitWriteLock();
}
}
internal static void CheckChildren(bool reapAll)
{
// This is called on SIGCHLD from a native thread.
// A lock in Process ensures no new processes are spawned while we are checking.
lock (s_childProcessWaitStates)
{
bool checkAll = false;
// Check terminated processes.
int pid;
do
{
// Find a process that terminated without reaping it yet.
pid = Interop.Sys.WaitIdAnyExitedNoHangNoWait();
if (pid > 0)
{
if (s_childProcessWaitStates.TryGetValue(pid, out ProcessWaitState pws))
{
// Known Process.
if (pws.TryReapChild())
{
pws.ReleaseRef();
}
}
else
{
// unlikely: This is not a managed Process, so we are not responsible for reaping.
// Fall back to checking all Processes.
checkAll = true;
break;
}
}
else if (pid == 0)
{
// No more terminated children.
}
else
{
// Unexpected.
int errorCode = Marshal.GetLastWin32Error();
Environment.FailFast("Error while checking for terminated children. errno = " + errorCode);
}
} while (pid > 0);
if (checkAll)
{
// We track things to unref so we don't invalidate our iterator by changing s_childProcessWaitStates.
ProcessWaitState firstToRemove = null;
List <ProcessWaitState> additionalToRemove = null;
foreach (KeyValuePair <int, ProcessWaitState> kv in s_childProcessWaitStates)
{
ProcessWaitState pws = kv.Value;
if (pws.TryReapChild())
{
if (firstToRemove == null)
{
firstToRemove = pws;
}
else
{
if (additionalToRemove == null)
{
additionalToRemove = new List <ProcessWaitState>();
}
additionalToRemove.Add(pws);
}
}
}
if (firstToRemove != null)
{
firstToRemove.ReleaseRef();
if (additionalToRemove != null)
{
foreach (ProcessWaitState pws in additionalToRemove)
{
pws.ReleaseRef();
}
}
}
}
if (reapAll)
{
do
{
int exitCode;
pid = Interop.Sys.WaitPidExitedNoHang(-1, out exitCode);
} while (pid > 0);
}
}
}
internal Holder(int processId, bool isNewChild = false, bool usesTerminal = false)
{
_state = ProcessWaitState.AddRef(processId, isNewChild, usesTerminal);
}