@@ -1,6 +1,6 @@

 # the following lines are in sorted order, FYI

 github.com/Azure/go-ansiterm d6e3b3328b783f23731bc4d058875b0371ff8109

-github.com/Microsoft/hcsshim ada9cb39f715fb568e1030e7613732bb4f1e4aeb

+github.com/Microsoft/hcsshim ba3d6667710fa905116f39a19d059c4c1016be7c

 github.com/Microsoft/go-winio c599b533b43b1363d7d7c6cfda5ede70ed73ff13

 github.com/docker/libtrust 9cbd2a1374f46905c68a4eb3694a130610adc62a

 github.com/go-check/check 4ed411733c5785b40214c70bce814c3a3a689609 https://github.com/cpuguy83/check.git

@@ -23,6 +23,10 @@ type Process struct {

 	callbackNumber uintptr

 	logctx logrus.Fields

+

+	closedWaitOnce sync.Once

+	waitBlock      chan struct{}

+	waitError      error

 }

 func newProcess(process hcsProcess, processID int, computeSystem *System) *Process {

@@ -34,6 +38,7 @@ func newProcess(process hcsProcess, processID int, computeSystem *System) *Proce

 			logfields.ContainerID: computeSystem.ID(),

 			logfields.ProcessID:   processID,

 		},

+		waitBlock: make(chan struct{}),

 	}

 }

@@ -163,33 +168,49 @@ func (process *Process) Kill() (err error) {

 	return nil

 }

-// Wait waits for the process to exit.

+// waitBackground waits for the process exit notification. Once received sets

+// `process.waitError` (if any) and unblocks all `Wait` and `WaitTimeout` calls.

+//

+// This MUST be called exactly once per `process.handle` but `Wait` and

+// `WaitTimeout` are safe to call multiple times.

+func (process *Process) waitBackground() {

+	process.waitError = waitForNotification(process.callbackNumber, hcsNotificationProcessExited, nil)

+	process.closedWaitOnce.Do(func() {

+		close(process.waitBlock)

+	})

+}

+

+// Wait waits for the process to exit. If the process has already exited returns

+// the pervious error (if any).

 func (process *Process) Wait() (err error) {

 	operation := "hcsshim::Process::Wait"

 	process.logOperationBegin(operation)

 	defer func() { process.logOperationEnd(operation, err) }()

-	err = waitForNotification(process.callbackNumber, hcsNotificationProcessExited, nil)

-	if err != nil {

+	<-process.waitBlock

+	if process.waitError != nil {

 		return makeProcessError(process, operation, err, nil)

 	}

-

 	return nil

 }

-// WaitTimeout waits for the process to exit or the duration to elapse. It returns

-// false if timeout occurs.

+// WaitTimeout waits for the process to exit or the duration to elapse. If the

+// process has already exited returns the pervious error (if any). If a timeout

+// occurs returns `ErrTimeout`.

 func (process *Process) WaitTimeout(timeout time.Duration) (err error) {

 	operation := "hcssshim::Process::WaitTimeout"

 	process.logOperationBegin(operation)

 	defer func() { process.logOperationEnd(operation, err) }()

-	err = waitForNotification(process.callbackNumber, hcsNotificationProcessExited, &timeout)

-	if err != nil {

-		return makeProcessError(process, operation, err, nil)

+	select {

+	case <-process.waitBlock:

+		if process.waitError != nil {

+			return makeProcessError(process, operation, process.waitError, nil)

+		}

+		return nil

+	case <-time.After(timeout):

+		return makeProcessError(process, operation, ErrTimeout, nil)

 	}

-

-	return nil

 }

 // ResizeConsole resizes the console of the process.

@@ -402,6 +423,9 @@ func (process *Process) Close() (err error) {

 	}

 	process.handle = 0

+	process.closedWaitOnce.Do(func() {

+		close(process.waitBlock)

+	})

 	return nil

 }

@@ -43,6 +43,10 @@ type System struct {

 	callbackNumber uintptr

 	logctx logrus.Fields

+

+	closedWaitOnce sync.Once

+	waitBlock      chan struct{}

+	waitError      error

 }

 func newSystem(id string) *System {

@@ -51,6 +55,7 @@ func newSystem(id string) *System {

 		logctx: logrus.Fields{

 			logfields.ContainerID: id,

 		},

+		waitBlock: make(chan struct{}),

 	}

 }

@@ -121,6 +126,8 @@ func CreateComputeSystem(id string, hcsDocumentInterface interface{}) (_ *System

 		return nil, makeSystemError(computeSystem, operation, hcsDocument, err, events)

 	}

+	go computeSystem.waitBackground()

+

 	return computeSystem, nil

 }

@@ -153,6 +160,7 @@ func OpenComputeSystem(id string) (_ *System, err error) {

 	if err = computeSystem.registerCallback(); err != nil {

 		return nil, makeSystemError(computeSystem, operation, "", err, nil)

 	}

+	go computeSystem.waitBackground()

 	return computeSystem, nil

 }

@@ -280,7 +288,7 @@ func (computeSystem *System) Shutdown() (err error) {

 	operation := "hcsshim::ComputeSystem::Shutdown"

 	computeSystem.logOperationBegin(operation)

 	defer func() {

-		if IsAlreadyStopped(err) || IsPending(err) {

+		if IsAlreadyClosed(err) || IsAlreadyStopped(err) || IsPending(err) {

 			computeSystem.logOperationEnd(operation, nil)

 		} else {

 			computeSystem.logOperationEnd(operation, err)

@@ -312,7 +320,7 @@ func (computeSystem *System) Terminate() (err error) {

 	operation := "hcsshim::ComputeSystem::Terminate"

 	computeSystem.logOperationBegin(operation)

 	defer func() {

-		if IsPending(err) {

+		if IsAlreadyClosed(err) || IsAlreadyStopped(err) || IsPending(err) {

 			computeSystem.logOperationEnd(operation, nil)

 		} else {

 			computeSystem.logOperationEnd(operation, err)

@@ -335,48 +343,67 @@ func (computeSystem *System) Terminate() (err error) {

 	return nil

 }

-// Wait synchronously waits for the compute system to shutdown or terminate.

+// waitBackground waits for the compute system exit notification. Once received

+// sets `computeSystem.waitError` (if any) and unblocks all `Wait`,

+// `WaitExpectedError`, and `WaitTimeout` calls.

+//

+// This MUST be called exactly once per `computeSystem.handle` but `Wait`,

+// `WaitExpectedError`, and `WaitTimeout` are safe to call multiple times.

+func (computeSystem *System) waitBackground() {

+	computeSystem.waitError = waitForNotification(computeSystem.callbackNumber, hcsNotificationSystemExited, nil)

+	computeSystem.closedWaitOnce.Do(func() {

+		close(computeSystem.waitBlock)

+	})

+}

+

+// Wait synchronously waits for the compute system to shutdown or terminate. If

+// the compute system has already exited returns the previous error (if any).

 func (computeSystem *System) Wait() (err error) {

 	operation := "hcsshim::ComputeSystem::Wait"

 	computeSystem.logOperationBegin(operation)

 	defer func() { computeSystem.logOperationEnd(operation, err) }()

-	err = waitForNotification(computeSystem.callbackNumber, hcsNotificationSystemExited, nil)

-	if err != nil {

-		return makeSystemError(computeSystem, "Wait", "", err, nil)

+	<-computeSystem.waitBlock

+	if computeSystem.waitError != nil {

+		return makeSystemError(computeSystem, "Wait", "", computeSystem.waitError, nil)

 	}

 	return nil

 }

 // WaitExpectedError synchronously waits for the compute system to shutdown or

-// terminate, and ignores the passed error if it occurs.

+// terminate and returns the error (if any) as long as it does not match

+// `expected`. If the compute system has already exited returns the previous

+// error (if any) as long as it does not match `expected`.

 func (computeSystem *System) WaitExpectedError(expected error) (err error) {

 	operation := "hcsshim::ComputeSystem::WaitExpectedError"

 	computeSystem.logOperationBegin(operation)

 	defer func() { computeSystem.logOperationEnd(operation, err) }()

-	err = waitForNotification(computeSystem.callbackNumber, hcsNotificationSystemExited, nil)

-	if err != nil && getInnerError(err) != expected {

-		return makeSystemError(computeSystem, "WaitExpectedError", "", err, nil)

+	<-computeSystem.waitBlock

+	if computeSystem.waitError != nil && getInnerError(computeSystem.waitError) != expected {

+		return makeSystemError(computeSystem, "WaitExpectedError", "", computeSystem.waitError, nil)

 	}

-

 	return nil

 }

-// WaitTimeout synchronously waits for the compute system to terminate or the duration to elapse.

-// If the timeout expires, IsTimeout(err) == true

+// WaitTimeout synchronously waits for the compute system to terminate or the

+// duration to elapse. If the timeout expires, `IsTimeout(err) == true`. If

+// the compute system has already exited returns the previous error (if any).

 func (computeSystem *System) WaitTimeout(timeout time.Duration) (err error) {

 	operation := "hcsshim::ComputeSystem::WaitTimeout"

 	computeSystem.logOperationBegin(operation)

 	defer func() { computeSystem.logOperationEnd(operation, err) }()

-	err = waitForNotification(computeSystem.callbackNumber, hcsNotificationSystemExited, &timeout)

-	if err != nil {

-		return makeSystemError(computeSystem, "WaitTimeout", "", err, nil)

+	select {

+	case <-computeSystem.waitBlock:

+		if computeSystem.waitError != nil {

+			return makeSystemError(computeSystem, "WaitTimeout", "", computeSystem.waitError, nil)

+		}

+		return nil

+	case <-time.After(timeout):

+		return makeSystemError(computeSystem, "WaitTimeout", "", ErrTimeout, nil)

 	}

-

-	return nil

 }

 func (computeSystem *System) Properties(types ...schema1.PropertyType) (_ *schema1.ContainerProperties, err error) {

@@ -519,6 +546,7 @@ func (computeSystem *System) CreateProcess(c interface{}) (_ *Process, err error

 	if err = process.registerCallback(); err != nil {

 		return nil, makeSystemError(computeSystem, "CreateProcess", "", err, nil)

 	}

+	go process.waitBackground()

 	return process, nil

 }

@@ -557,6 +585,7 @@ func (computeSystem *System) OpenProcess(pid int) (_ *Process, err error) {

 	if err = process.registerCallback(); err != nil {

 		return nil, makeSystemError(computeSystem, "OpenProcess", "", err, nil)

 	}

+	go process.waitBackground()

 	return process, nil

 }

@@ -587,6 +616,9 @@ func (computeSystem *System) Close() (err error) {

 	}

 	computeSystem.handle = 0

+	computeSystem.closedWaitOnce.Do(func() {

+		close(computeSystem.waitBlock)

+	})

 	return nil

 }

@@ -10,7 +10,7 @@ github.com/hashicorp/errwrap 7554cd9344cec97297fa6649b055a8c98c2a1e55

 github.com/hashicorp/go-multierror ed905158d87462226a13fe39ddf685ea65f1c11f

 github.com/konsorten/go-windows-terminal-sequences v1.0.1

 github.com/linuxkit/virtsock 8e79449dea0735c1c056d814934dd035734cc97c

-github.com/Microsoft/go-winio 16cfc975803886a5e47c4257a24c8d8c52e178b2

+github.com/Microsoft/go-winio c599b533b43b1363d7d7c6cfda5ede70ed73ff13

 github.com/Microsoft/opengcs v0.3.9

 github.com/opencontainers/go-digest c9281466c8b2f606084ac71339773efd177436e7

 github.com/opencontainers/runc 12f6a991201fdb8f82579582d5e00e28fba06d0a