cloudflared-mirror/cmd/cloudflared/windows_service.go

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//go:build windows
package main
// Copypasta from the example files:
// https://github.com/golang/sys/blob/master/windows/svc/example
import (
"fmt"
"os"
"syscall"
"time"
"unsafe"
"github.com/pkg/errors"
"github.com/urfave/cli/v2"
"golang.org/x/sys/windows"
"golang.org/x/sys/windows/svc"
"golang.org/x/sys/windows/svc/eventlog"
"golang.org/x/sys/windows/svc/mgr"
"github.com/cloudflare/cloudflared/cmd/cloudflared/cliutil"
"github.com/cloudflare/cloudflared/logger"
)
const (
windowsServiceName = "Cloudflared"
windowsServiceDescription = "Cloudflared agent"
windowsServiceUrl = "https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/run-tunnel/as-a-service/windows/"
recoverActionDelay = time.Second * 20
failureCountResetPeriod = time.Hour * 24
// not defined in golang.org/x/sys/windows package
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms681988(v=vs.85).aspx
serviceConfigFailureActionsFlag = 4
// ERROR_FAILED_SERVICE_CONTROLLER_CONNECT
// https://docs.microsoft.com/en-us/windows/desktop/debug/system-error-codes--1000-1299-
serviceControllerConnectionFailure = 1063
LogFieldWindowsServiceName = "windowsServiceName"
)
func runApp(app *cli.App, graceShutdownC chan struct{}) {
app.Commands = append(app.Commands, &cli.Command{
Name: "service",
Usage: "Manages the cloudflared Windows service",
Subcommands: []*cli.Command{
{
Name: "install",
Usage: "Install cloudflared as a Windows service",
Action: cliutil.ConfiguredAction(installWindowsService),
},
{
Name: "uninstall",
Usage: "Uninstall the cloudflared service",
Action: cliutil.ConfiguredAction(uninstallWindowsService),
},
},
})
// `IsAnInteractiveSession()` isn't exactly equivalent to "should the
// process run as a normal EXE?" There are legitimate non-service cases,
// like running cloudflared in a GCP startup script, for which
// `IsAnInteractiveSession()` returns false. For more context, see:
// https://github.com/judwhite/go-svc/issues/6
// It seems that the "correct way" to check "is this a normal EXE?" is:
// 1. attempt to connect to the Service Control Manager
// 2. get ERROR_FAILED_SERVICE_CONTROLLER_CONNECT
// This involves actually trying to start the service.
log := logger.Create(nil)
isIntSess, err := svc.IsAnInteractiveSession()
if err != nil {
log.Fatal().Err(err).Msg("failed to determine if we are running in an interactive session")
}
if isIntSess {
app.Run(os.Args)
return
}
// Run executes service name by calling windowsService which is a Handler
// interface that implements Execute method.
// It will set service status to stop after Execute returns
err = svc.Run(windowsServiceName, &windowsService{app: app, graceShutdownC: graceShutdownC})
if err != nil {
if errno, ok := err.(syscall.Errno); ok && int(errno) == serviceControllerConnectionFailure {
// Hack: assume this is a false negative from the IsAnInteractiveSession() check above.
// Run the app in "interactive" mode anyway.
app.Run(os.Args)
return
}
log.Fatal().Err(err).Msgf("%s service failed", windowsServiceName)
}
}
type windowsService struct {
app *cli.App
graceShutdownC chan struct{}
}
// Execute is called by the service manager when service starts, the state
// of the service will be set to Stopped when this function returns.
func (s *windowsService) Execute(serviceArgs []string, r <-chan svc.ChangeRequest, statusChan chan<- svc.Status) (ssec bool, errno uint32) {
log := logger.Create(nil)
elog, err := eventlog.Open(windowsServiceName)
if err != nil {
log.Err(err).Msgf("Cannot open event log for %s", windowsServiceName)
return
}
defer elog.Close()
elog.Info(1, fmt.Sprintf("%s service starting", windowsServiceName))
defer func() {
elog.Info(1, fmt.Sprintf("%s service stopped", windowsServiceName))
}()
// the arguments passed here are only meaningful if they were manually
// specified by the user, e.g. using the Services console or `sc start`.
// https://docs.microsoft.com/en-us/windows/desktop/services/service-entry-point
// https://stackoverflow.com/a/6235139
var args []string
if len(serviceArgs) > 1 {
args = serviceArgs
} else {
// fall back to the arguments from ImagePath (or, as sc calls it, binPath)
args = os.Args
}
elog.Info(1, fmt.Sprintf("%s service arguments: %v", windowsServiceName, args))
statusChan <- svc.Status{State: svc.StartPending}
errC := make(chan error)
go func() {
errC <- s.app.Run(args)
}()
statusChan <- svc.Status{State: svc.Running, Accepts: svc.AcceptStop | svc.AcceptShutdown}
for {
select {
case c := <-r:
switch c.Cmd {
case svc.Interrogate:
statusChan <- c.CurrentStatus
case svc.Stop, svc.Shutdown:
if s.graceShutdownC != nil {
// start graceful shutdown
elog.Info(1, "cloudflared starting graceful shutdown")
close(s.graceShutdownC)
s.graceShutdownC = nil
statusChan <- svc.Status{State: svc.StopPending}
continue
}
// repeated attempts at graceful shutdown forces immediate stop
elog.Info(1, "cloudflared terminating immediately")
statusChan <- svc.Status{State: svc.StopPending}
return false, 0
default:
elog.Error(1, fmt.Sprintf("unexpected control request #%d", c))
}
case err := <-errC:
if err != nil {
elog.Error(1, fmt.Sprintf("cloudflared terminated with error %v", err))
ssec = true
errno = 1
} else {
elog.Info(1, "cloudflared terminated without error")
errno = 0
}
return
}
}
}
func installWindowsService(c *cli.Context) error {
zeroLogger := logger.CreateLoggerFromContext(c, logger.EnableTerminalLog)
zeroLogger.Info().Msg("Installing cloudflared Windows service")
exepath, err := os.Executable()
if err != nil {
return errors.Wrap(err, "Cannot find path name that start the process")
}
m, err := mgr.Connect()
if err != nil {
return errors.Wrap(err, "Cannot establish a connection to the service control manager")
}
defer m.Disconnect()
s, err := m.OpenService(windowsServiceName)
log := zeroLogger.With().Str(LogFieldWindowsServiceName, windowsServiceName).Logger()
if err == nil {
s.Close()
return fmt.Errorf(serviceAlreadyExistsWarn(windowsServiceName))
}
extraArgs, err := getServiceExtraArgsFromCliArgs(c, &log)
if err != nil {
errMsg := "Unable to determine extra arguments for windows service"
log.Err(err).Msg(errMsg)
return errors.Wrap(err, errMsg)
}
config := mgr.Config{StartType: mgr.StartAutomatic, DisplayName: windowsServiceDescription}
s, err = m.CreateService(windowsServiceName, exepath, config, extraArgs...)
if err != nil {
return errors.Wrap(err, "Cannot install service")
}
defer s.Close()
log.Info().Msg("cloudflared agent service is installed")
err = eventlog.InstallAsEventCreate(windowsServiceName, eventlog.Error|eventlog.Warning|eventlog.Info)
if err != nil {
s.Delete()
return errors.Wrap(err, "Cannot install event logger")
}
err = configRecoveryOption(s.Handle)
if err != nil {
log.Err(err).Msg("Cannot set service recovery actions")
log.Info().Msgf("See %s to manually configure service recovery actions", windowsServiceUrl)
}
err = s.Start()
if err == nil {
log.Info().Msg("Agent service for cloudflared installed successfully")
}
return err
}
func uninstallWindowsService(c *cli.Context) error {
log := logger.CreateLoggerFromContext(c, logger.EnableTerminalLog).
With().
Str(LogFieldWindowsServiceName, windowsServiceName).Logger()
log.Info().Msg("Uninstalling cloudflared agent service")
m, err := mgr.Connect()
if err != nil {
return errors.Wrap(err, "Cannot establish a connection to the service control manager")
}
defer m.Disconnect()
s, err := m.OpenService(windowsServiceName)
if err != nil {
return fmt.Errorf("Agent service %s is not installed, so it could not be uninstalled", windowsServiceName)
}
defer s.Close()
if status, err := s.Query(); err == nil && status.State == svc.Running {
log.Info().Msg("Stopping cloudflared agent service")
if _, err := s.Control(svc.Stop); err != nil {
log.Info().Err(err).Msg("Failed to stop cloudflared agent service, you may need to stop it manually to complete uninstall.")
}
}
err = s.Delete()
if err != nil {
return errors.Wrap(err, "Cannot delete agent service")
}
log.Info().Msg("Agent service for cloudflared was uninstalled successfully")
err = eventlog.Remove(windowsServiceName)
if err != nil {
return errors.Wrap(err, "Cannot remove event logger")
}
return nil
}
// defined in https://msdn.microsoft.com/en-us/library/windows/desktop/ms685126(v=vs.85).aspx
type scAction int
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms685126(v=vs.85).aspx
const (
scActionNone scAction = iota
scActionRestart
scActionReboot
scActionRunCommand
)
// defined in https://msdn.microsoft.com/en-us/library/windows/desktop/ms685939(v=vs.85).aspx
type serviceFailureActions struct {
// time to wait to reset the failure count to zero if there are no failures in seconds
resetPeriod uint32
rebootMsg *uint16
command *uint16
// If failure count is greater than actionCount, the service controller repeats
// the last action in actions
actionCount uint32
actions uintptr
}
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms685937(v=vs.85).aspx
// Not supported in Windows Server 2003 and Windows XP
type serviceFailureActionsFlag struct {
// enableActionsForStopsWithErr is of type BOOL, which is declared as
// typedef int BOOL in C
enableActionsForStopsWithErr int
}
type recoveryAction struct {
recoveryType uint32
// The time to wait before performing the specified action, in milliseconds
delay uint32
}
// until https://github.com/golang/go/issues/23239 is release, we will need to
// configure through ChangeServiceConfig2
func configRecoveryOption(handle windows.Handle) error {
actions := []recoveryAction{
{recoveryType: uint32(scActionRestart), delay: uint32(recoverActionDelay / time.Millisecond)},
}
serviceRecoveryActions := serviceFailureActions{
resetPeriod: uint32(failureCountResetPeriod / time.Second),
actionCount: uint32(len(actions)),
actions: uintptr(unsafe.Pointer(&actions[0])),
}
if err := windows.ChangeServiceConfig2(handle, windows.SERVICE_CONFIG_FAILURE_ACTIONS, (*byte)(unsafe.Pointer(&serviceRecoveryActions))); err != nil {
return err
}
serviceFailureActionsFlag := serviceFailureActionsFlag{enableActionsForStopsWithErr: 1}
return windows.ChangeServiceConfig2(handle, serviceConfigFailureActionsFlag, (*byte)(unsafe.Pointer(&serviceFailureActionsFlag)))
}