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

475 lines
12 KiB
Go

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
hasCachedStdio bool
stdioLock sync.Mutex
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. Once returned, these pipes
// are the responsibility of the caller to close.
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)
}
process.stdioLock.Lock()
defer process.stdioLock.Unlock()
if process.hasCachedStdio {
stdin, stdout, stderr := process.stdin, process.stdout, process.stderr
process.stdin, process.stdout, process.stderr = nil, nil, nil
process.hasCachedStdio = false
return stdin, stdout, stderr, 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) {
process.stdioLock.Lock()
defer process.stdioLock.Unlock()
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)
}
process.stdioLock.Lock()
if process.stdin != nil {
process.stdin.Close()
process.stdin = nil
}
process.stdioLock.Unlock()
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
}
process.stdioLock.Lock()
if process.stdin != nil {
process.stdin.Close()
process.stdin = nil
}
if process.stdout != nil {
process.stdout.Close()
process.stdout = nil
}
if process.stderr != nil {
process.stderr.Close()
process.stderr = nil
}
process.stdioLock.Unlock()
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
}