Initial

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

vendor/github.com/Microsoft/hcsshim/internal/hcs/process.go

@@ -0,0 +1,452 @@
+package hcs
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/Microsoft/hcsshim/internal/log"
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/Microsoft/hcsshim/internal/vmcompute"
+	"go.opencensus.io/trace"
+)
+
+// ContainerError is an error encountered in HCS
+type Process struct {
+	handleLock     sync.RWMutex
+	handle         vmcompute.HcsProcess
+	processID      int
+	system         *System
+	stdin          io.WriteCloser
+	stdout         io.ReadCloser
+	stderr         io.ReadCloser
+	callbackNumber uintptr
+
+	closedWaitOnce sync.Once
+	waitBlock      chan struct{}
+	exitCode       int
+	waitError      error
+}
+
+func newProcess(process vmcompute.HcsProcess, processID int, computeSystem *System) *Process {
+	return &Process{
+		handle:    process,
+		processID: processID,
+		system:    computeSystem,
+		waitBlock: make(chan struct{}),
+	}
+}
+
+type processModifyRequest struct {
+	Operation   string
+	ConsoleSize *consoleSize `json:",omitempty"`
+	CloseHandle *closeHandle `json:",omitempty"`
+}
+
+type consoleSize struct {
+	Height uint16
+	Width  uint16
+}
+
+type closeHandle struct {
+	Handle string
+}
+
+type processStatus struct {
+	ProcessID      uint32
+	Exited         bool
+	ExitCode       uint32
+	LastWaitResult int32
+}
+
+const (
+	stdIn  string = "StdIn"
+	stdOut string = "StdOut"
+	stdErr string = "StdErr"
+)
+
+const (
+	modifyConsoleSize string = "ConsoleSize"
+	modifyCloseHandle string = "CloseHandle"
+)
+
+// Pid returns the process ID of the process within the container.
+func (process *Process) Pid() int {
+	return process.processID
+}
+
+// SystemID returns the ID of the process's compute system.
+func (process *Process) SystemID() string {
+	return process.system.ID()
+}
+
+func (process *Process) processSignalResult(ctx context.Context, err error) (bool, error) {
+	switch err {
+	case nil:
+		return true, nil
+	case ErrVmcomputeOperationInvalidState, ErrComputeSystemDoesNotExist, ErrElementNotFound:
+		select {
+		case <-process.waitBlock:
+			// The process exit notification has already arrived.
+		default:
+			// The process should be gone, but we have not received the notification.
+			// After a second, force unblock the process wait to work around a possible
+			// deadlock in the HCS.
+			go func() {
+				time.Sleep(time.Second)
+				process.closedWaitOnce.Do(func() {
+					log.G(ctx).WithError(err).Warn("force unblocking process waits")
+					process.exitCode = -1
+					process.waitError = err
+					close(process.waitBlock)
+				})
+			}()
+		}
+		return false, nil
+	default:
+		return false, err
+	}
+}
+
+// Signal signals the process with `options`.
+//
+// For LCOW `guestrequest.SignalProcessOptionsLCOW`.
+//
+// For WCOW `guestrequest.SignalProcessOptionsWCOW`.
+func (process *Process) Signal(ctx context.Context, options interface{}) (bool, error) {
+	process.handleLock.RLock()
+	defer process.handleLock.RUnlock()
+
+	operation := "hcsshim::Process::Signal"
+
+	if process.handle == 0 {
+		return false, makeProcessError(process, operation, ErrAlreadyClosed, nil)
+	}
+
+	optionsb, err := json.Marshal(options)
+	if err != nil {
+		return false, err
+	}
+
+	resultJSON, err := vmcompute.HcsSignalProcess(ctx, process.handle, string(optionsb))
+	events := processHcsResult(ctx, resultJSON)
+	delivered, err := process.processSignalResult(ctx, err)
+	if err != nil {
+		err = makeProcessError(process, operation, err, events)
+	}
+	return delivered, err
+}
+
+// Kill signals the process to terminate but does not wait for it to finish terminating.
+func (process *Process) Kill(ctx context.Context) (bool, error) {
+	process.handleLock.RLock()
+	defer process.handleLock.RUnlock()
+
+	operation := "hcsshim::Process::Kill"
+
+	if process.handle == 0 {
+		return false, makeProcessError(process, operation, ErrAlreadyClosed, nil)
+	}
+
+	resultJSON, err := vmcompute.HcsTerminateProcess(ctx, process.handle)
+	events := processHcsResult(ctx, resultJSON)
+	delivered, err := process.processSignalResult(ctx, err)
+	if err != nil {
+		err = makeProcessError(process, operation, err, events)
+	}
+	return delivered, err
+}
+
+// waitBackground waits for the process exit notification. Once received sets
+// `process.waitError` (if any) and unblocks all `Wait` calls.
+//
+// This MUST be called exactly once per `process.handle` but `Wait` is safe to
+// call multiple times.
+func (process *Process) waitBackground() {
+	operation := "hcsshim::Process::waitBackground"
+	ctx, span := trace.StartSpan(context.Background(), operation)
+	defer span.End()
+	span.AddAttributes(
+		trace.StringAttribute("cid", process.SystemID()),
+		trace.Int64Attribute("pid", int64(process.processID)))
+
+	var (
+		err      error
+		exitCode = -1
+	)
+
+	err = waitForNotification(ctx, process.callbackNumber, hcsNotificationProcessExited, nil)
+	if err != nil {
+		err = makeProcessError(process, operation, err, nil)
+		log.G(ctx).WithError(err).Error("failed wait")
+	} else {
+		process.handleLock.RLock()
+		defer process.handleLock.RUnlock()
+
+		// Make sure we didnt race with Close() here
+		if process.handle != 0 {
+			propertiesJSON, resultJSON, err := vmcompute.HcsGetProcessProperties(ctx, process.handle)
+			events := processHcsResult(ctx, resultJSON)
+			if err != nil {
+				err = makeProcessError(process, operation, err, events)
+			} else {
+				properties := &processStatus{}
+				err = json.Unmarshal([]byte(propertiesJSON), properties)
+				if err != nil {
+					err = makeProcessError(process, operation, err, nil)
+				} else {
+					if properties.LastWaitResult != 0 {
+						log.G(ctx).WithField("wait-result", properties.LastWaitResult).Warning("non-zero last wait result")
+					} else {
+						exitCode = int(properties.ExitCode)
+					}
+				}
+			}
+		}
+	}
+	log.G(ctx).WithField("exitCode", exitCode).Debug("process exited")
+
+	process.closedWaitOnce.Do(func() {
+		process.exitCode = exitCode
+		process.waitError = err
+		close(process.waitBlock)
+	})
+	oc.SetSpanStatus(span, err)
+}
+
+// Wait waits for the process to exit. If the process has already exited returns
+// the pervious error (if any).
+func (process *Process) Wait() error {
+	<-process.waitBlock
+	return process.waitError
+}
+
+// ResizeConsole resizes the console of the process.
+func (process *Process) ResizeConsole(ctx context.Context, width, height uint16) error {
+	process.handleLock.RLock()
+	defer process.handleLock.RUnlock()
+
+	operation := "hcsshim::Process::ResizeConsole"
+
+	if process.handle == 0 {
+		return makeProcessError(process, operation, ErrAlreadyClosed, nil)
+	}
+
+	modifyRequest := processModifyRequest{
+		Operation: modifyConsoleSize,
+		ConsoleSize: &consoleSize{
+			Height: height,
+			Width:  width,
+		},
+	}
+
+	modifyRequestb, err := json.Marshal(modifyRequest)
+	if err != nil {
+		return err
+	}
+
+	resultJSON, err := vmcompute.HcsModifyProcess(ctx, process.handle, string(modifyRequestb))
+	events := processHcsResult(ctx, resultJSON)
+	if err != nil {
+		return makeProcessError(process, operation, err, events)
+	}
+
+	return nil
+}
+
+// ExitCode returns the exit code of the process. The process must have
+// already terminated.
+func (process *Process) ExitCode() (int, error) {
+	select {
+	case <-process.waitBlock:
+		if process.waitError != nil {
+			return -1, process.waitError
+		}
+		return process.exitCode, nil
+	default:
+		return -1, makeProcessError(process, "hcsshim::Process::ExitCode", ErrInvalidProcessState, nil)
+	}
+}
+
+// StdioLegacy returns the stdin, stdout, and stderr pipes, respectively. Closing
+// these pipes does not close the underlying pipes; but this function can only
+// be called once on each Process.
+func (process *Process) StdioLegacy() (_ io.WriteCloser, _ io.ReadCloser, _ io.ReadCloser, err error) {
+	operation := "hcsshim::Process::StdioLegacy"
+	ctx, span := trace.StartSpan(context.Background(), operation)
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("cid", process.SystemID()),
+		trace.Int64Attribute("pid", int64(process.processID)))
+
+	process.handleLock.RLock()
+	defer process.handleLock.RUnlock()
+
+	if process.handle == 0 {
+		return nil, nil, nil, makeProcessError(process, operation, ErrAlreadyClosed, nil)
+	}
+
+	processInfo, resultJSON, err := vmcompute.HcsGetProcessInfo(ctx, process.handle)
+	events := processHcsResult(ctx, resultJSON)
+	if err != nil {
+		return nil, nil, nil, makeProcessError(process, operation, err, events)
+	}
+
+	pipes, err := makeOpenFiles([]syscall.Handle{processInfo.StdInput, processInfo.StdOutput, processInfo.StdError})
+	if err != nil {
+		return nil, nil, nil, makeProcessError(process, operation, err, nil)
+	}
+
+	return pipes[0], pipes[1], pipes[2], nil
+}
+
+// Stdio returns the stdin, stdout, and stderr pipes, respectively.
+// To close them, close the process handle.
+func (process *Process) Stdio() (stdin io.Writer, stdout, stderr io.Reader) {
+	return process.stdin, process.stdout, process.stderr
+}
+
+// CloseStdin closes the write side of the stdin pipe so that the process is
+// notified on the read side that there is no more data in stdin.
+func (process *Process) CloseStdin(ctx context.Context) error {
+	process.handleLock.RLock()
+	defer process.handleLock.RUnlock()
+
+	operation := "hcsshim::Process::CloseStdin"
+
+	if process.handle == 0 {
+		return makeProcessError(process, operation, ErrAlreadyClosed, nil)
+	}
+
+	modifyRequest := processModifyRequest{
+		Operation: modifyCloseHandle,
+		CloseHandle: &closeHandle{
+			Handle: stdIn,
+		},
+	}
+
+	modifyRequestb, err := json.Marshal(modifyRequest)
+	if err != nil {
+		return err
+	}
+
+	resultJSON, err := vmcompute.HcsModifyProcess(ctx, process.handle, string(modifyRequestb))
+	events := processHcsResult(ctx, resultJSON)
+	if err != nil {
+		return makeProcessError(process, operation, err, events)
+	}
+
+	if process.stdin != nil {
+		process.stdin.Close()
+	}
+	return nil
+}
+
+// Close cleans up any state associated with the process but does not kill
+// or wait on it.
+func (process *Process) Close() (err error) {
+	operation := "hcsshim::Process::Close"
+	ctx, span := trace.StartSpan(context.Background(), operation)
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("cid", process.SystemID()),
+		trace.Int64Attribute("pid", int64(process.processID)))
+
+	process.handleLock.Lock()
+	defer process.handleLock.Unlock()
+
+	// Don't double free this
+	if process.handle == 0 {
+		return nil
+	}
+
+	if process.stdin != nil {
+		process.stdin.Close()
+	}
+	if process.stdout != nil {
+		process.stdout.Close()
+	}
+	if process.stderr != nil {
+		process.stderr.Close()
+	}
+
+	if err = process.unregisterCallback(ctx); err != nil {
+		return makeProcessError(process, operation, err, nil)
+	}
+
+	if err = vmcompute.HcsCloseProcess(ctx, process.handle); err != nil {
+		return makeProcessError(process, operation, err, nil)
+	}
+
+	process.handle = 0
+	process.closedWaitOnce.Do(func() {
+		process.exitCode = -1
+		process.waitError = ErrAlreadyClosed
+		close(process.waitBlock)
+	})
+
+	return nil
+}
+
+func (process *Process) registerCallback(ctx context.Context) error {
+	callbackContext := &notifcationWatcherContext{
+		channels:  newProcessChannels(),
+		systemID:  process.SystemID(),
+		processID: process.processID,
+	}
+
+	callbackMapLock.Lock()
+	callbackNumber := nextCallback
+	nextCallback++
+	callbackMap[callbackNumber] = callbackContext
+	callbackMapLock.Unlock()
+
+	callbackHandle, err := vmcompute.HcsRegisterProcessCallback(ctx, process.handle, notificationWatcherCallback, callbackNumber)
+	if err != nil {
+		return err
+	}
+	callbackContext.handle = callbackHandle
+	process.callbackNumber = callbackNumber
+
+	return nil
+}
+
+func (process *Process) unregisterCallback(ctx context.Context) error {
+	callbackNumber := process.callbackNumber
+
+	callbackMapLock.RLock()
+	callbackContext := callbackMap[callbackNumber]
+	callbackMapLock.RUnlock()
+
+	if callbackContext == nil {
+		return nil
+	}
+
+	handle := callbackContext.handle
+
+	if handle == 0 {
+		return nil
+	}
+
+	// vmcompute.HcsUnregisterProcessCallback has its own synchronization to
+	// wait for all callbacks to complete. We must NOT hold the callbackMapLock.
+	err := vmcompute.HcsUnregisterProcessCallback(ctx, handle)
+	if err != nil {
+		return err
+	}
+
+	closeChannels(callbackContext.channels)
+
+	callbackMapLock.Lock()
+	delete(callbackMap, callbackNumber)
+	callbackMapLock.Unlock()
+
+	handle = 0
+
+	return nil
+}