/// <summary>
/// Called right after the process starts executing.
///
/// Since we set the process file name to be /bin/sh and its arguments to be empty (<see cref="CreateProcess"/>),
/// the process will effectively start in a "suspended" mode, with /bin/sh just waiting for some content to be
/// piped to its standard input. Therefore, in this handler we first notify the sandbox of the new process (so that
/// it starts tracking it) and then just send the actual process command line to /bin/sh via its standard input.
/// </summary>
private async Task OnProcessStartedAsync(SandboxedProcessInfo info)
{
// Generate "Process Created" report because the rest of the system expects to see it before any other file access reports
//
// IMPORTANT: do this before notifying sandbox kernel extension, because otherwise it can happen that a report
// from the extension is received before the "process created" report is handled, causing
// a "Should see a process creation before its accesses" assertion exception.
ReportProcessCreated();
// Allow read access for /bin/sh
// When executed using external tool, the manifest tree has been sealed, and cannot be modified.
// We take care of adding this path in the manifest in SandboxedProcessPipExecutor.cs;
// see AddUnixSpecificSandcboxedProcessFileAccessPolicies
if (!info.FileAccessManifest.IsManifestTreeBlockSealed)
{
info.FileAccessManifest.AddPath(
AbsolutePath.Create(PathTable, Process.StartInfo.FileName),
mask: FileAccessPolicy.MaskNothing,
values: FileAccessPolicy.AllowReadAlways);
}
if (OperatingSystemHelper.IsLinuxOS)
{
m_perfCollector?.Start();
}
string processStdinFileName = await FlushStandardInputToFileIfNeededAsync(info);
if (!SandboxConnection.NotifyPipStarted(info.LoggingContext, info.FileAccessManifest, this))
{
ThrowCouldNotStartProcess("Failed to initialize the sandbox for process observation, make sure BuildXL is setup correctly!");
}
try
{
await FeedStdInAsync(info, processStdinFileName);
m_processTreeTimeoutTask = ProcessTreeTimeoutTask();
}
catch (IOException e)
{
// IOException can happen if the process is forcefully killed while we're feeding its std in.
// When that happens, instead of crashing, just make sure the process is killed.
LogProcessState($"IOException caught while feeding the standard input: {e.ToString()}");
await KillAsync();
}
finally
{
// release the FileAccessManifest memory
// NOTE: just by not keeping any references to 'info' should make the FileAccessManifest object
// unreachable and thus available for garbage collection. We call Release() here explicitly
// just to emphasize the importance of reclaiming this memory.
info.FileAccessManifest.Release();
}
}
public void MultipleActionStartsTest()
{
var mre = new ManualResetEvent(false);
int counter = 0;
using (var timedAction = new CancellableTimedAction(() =>
{
// Signal that thread is started
mre.Set();
++counter;
}, 10, nameof(MultipleActionStartsTest)))
{
XAssert.IsTrue(timedAction.Start());
XAssert.IsFalse(timedAction.Start());
Thread.Sleep(500);
XAssert.IsFalse(timedAction.Start());
timedAction.Cancel();
timedAction.Join();
XAssert.IsTrue(counter > 2, "Value of counter is " + counter);
}
}
public void LongIntervalTest()
{
int counter = 0;
using (var timedAction = new CancellableTimedAction(() => Interlocked.Increment(ref counter), 1000, nameof(LongIntervalTest)))
{
var sw = System.Diagnostics.Stopwatch.StartNew();
XAssert.IsTrue(timedAction.Start());
Thread.Sleep(100);
timedAction.Cancel();
timedAction.Join();
sw.Stop();
XAssert.AreEqual(1, counter);
XAssert.IsTrue(sw.ElapsedMilliseconds < 1000);
}
}
/// <summary>
/// Removes <paramref name="pid" /> from the set of active processes.
/// If no active processes are left thereafter, calls <see cref="RequestStop"/>.
/// </summary>
internal void RemovePid(int pid)
{
bool removed = m_activeProcesses.TryRemove(pid, out var _);
LogDebug($"RemovePid({pid}) :: removed: {removed}; size: {m_activeProcesses.Count()}");
if (m_activeProcesses.Count == 0)
{
RequestStop();
}
else if (removed && pid == Process.ProcessId)
{
// We just removed the root process and there are still active processes left
// => start periodically checking if they are still alive, because we don't
// have a reliable mechanism for receiving those events straight from the
// child processes (e.g., if they crash, we might not hear about it)
//
// Observe also that we do have a reliable mechanism for detecting when the
// root process exits (even if it crashes): see NotifyRootProcessExited below,
// which is guaranteed to be called by SandboxedProcessUnix.
m_activeProcessesChecker.Start();
}
}
public void BasicFunctionalityTest()
{
var mre = new ManualResetEvent(false);
int counter = 0;
using (var timedAction = new CancellableTimedAction(() =>
{
// Signal that thread is started
mre.Set();
++counter;
}, 10, nameof(BasicFunctionalityTest)))
{
XAssert.IsTrue(timedAction.Start());
// Wait for thread to start
mre.WaitOne();
Thread.Sleep(500);
timedAction.Cancel();
timedAction.Join();
XAssert.IsTrue(counter > 2, "Value of counter is " + counter);
}
}
