cloudflared-mirror/cmd/cloudflared/windows_service.go

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// +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/cloudflare/cloudflared/logger"
"github.com/pkg/errors"
cli "gopkg.in/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"
)
const (
windowsServiceName = "Cloudflared"
windowsServiceDescription = "Argo Tunnel agent"
windowsServiceUrl = "https://developers.cloudflare.com/argo-tunnel/reference/service/"
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
)
func runApp(app *cli.App, shutdownC, graceShutdownC chan struct{}) {
app.Commands = append(app.Commands, &cli.Command{
Name: "service",
Usage: "Manages the Argo Tunnel Windows service",
Subcommands: []*cli.Command{
&cli.Command{
Name: "install",
Usage: "Install Argo Tunnel as a Windows service",
Action: installWindowsService,
},
&cli.Command{
Name: "uninstall",
Usage: "Uninstall the Argo Tunnel service",
Action: 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.
logger, err := logger.New()
if err != nil {
os.Exit(1)
return
}
isIntSess, err := svc.IsAnInteractiveSession()
if err != nil {
logger.Fatalf("failed to determine if we are running in an interactive session: %v", err)
}
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, shutdownC: shutdownC, 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
}
logger.Fatalf("%s service failed: %v", windowsServiceName, err)
}
}
type windowsService struct {
app *cli.App
shutdownC chan struct{}
graceShutdownC chan struct{}
}
// called by the package code at the start of the service
func (s *windowsService) Execute(serviceArgs []string, r <-chan svc.ChangeRequest, statusChan chan<- svc.Status) (ssec bool, errno uint32) {
logger, err := logger.New()
if err != nil {
os.Exit(1)
return
}
elog, err := eventlog.Open(windowsServiceName)
if err != nil {
logger.Errorf("Cannot open event log for %s with error: %s", windowsServiceName, err)
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))
const cmdsAccepted = svc.AcceptStop | svc.AcceptShutdown
statusChan <- svc.Status{State: svc.StartPending}
errC := make(chan error)
go func() {
errC <- s.app.Run(args)
}()
statusChan <- svc.Status{State: svc.Running, Accepts: cmdsAccepted}
for {
select {
case c := <-r:
switch c.Cmd {
case svc.Interrogate:
statusChan <- c.CurrentStatus
case svc.Stop:
close(s.graceShutdownC)
statusChan <- svc.Status{State: svc.StopPending}
case svc.Shutdown:
close(s.shutdownC)
statusChan <- svc.Status{State: svc.StopPending}
default:
elog.Error(1, fmt.Sprintf("unexpected control request #%d", c))
}
case err := <-errC:
ssec = true
if err != nil {
elog.Error(1, fmt.Sprintf("cloudflared terminated with error %v", err))
errno = 1
} else {
elog.Info(1, "cloudflared terminated without error")
errno = 0
}
return
}
}
}
func installWindowsService(c *cli.Context) error {
logger, err := logger.New()
if err != nil {
return errors.Wrap(err, "error setting up logger")
}
logger.Infof("Installing Argo Tunnel Windows service")
exepath, err := os.Executable()
if err != nil {
logger.Errorf("Cannot find path name that start the process")
return err
}
m, err := mgr.Connect()
if err != nil {
logger.Errorf("Cannot establish a connection to the service control manager: %s", err)
return err
}
defer m.Disconnect()
s, err := m.OpenService(windowsServiceName)
if err == nil {
s.Close()
logger.Errorf("service %s already exists", windowsServiceName)
return fmt.Errorf("service %s already exists", windowsServiceName)
}
config := mgr.Config{StartType: mgr.StartAutomatic, DisplayName: windowsServiceDescription}
s, err = m.CreateService(windowsServiceName, exepath, config)
if err != nil {
logger.Errorf("Cannot install service %s", windowsServiceName)
return err
}
defer s.Close()
logger.Infof("Argo Tunnel agent service is installed")
err = eventlog.InstallAsEventCreate(windowsServiceName, eventlog.Error|eventlog.Warning|eventlog.Info)
if err != nil {
s.Delete()
logger.Errorf("Cannot install event logger: %s", err)
return fmt.Errorf("SetupEventLogSource() failed: %s", err)
}
err = configRecoveryOption(s.Handle)
if err != nil {
logger.Errorf("Cannot set service recovery actions: %s", err)
logger.Infof("See %s to manually configure service recovery actions", windowsServiceUrl)
}
return nil
}
func uninstallWindowsService(c *cli.Context) error {
logger, err := logger.New()
if err != nil {
return errors.Wrap(err, "error setting up logger")
}
logger.Infof("Uninstalling Argo Tunnel Windows Service")
m, err := mgr.Connect()
if err != nil {
logger.Errorf("Cannot establish a connection to the service control manager")
return err
}
defer m.Disconnect()
s, err := m.OpenService(windowsServiceName)
if err != nil {
logger.Errorf("service %s is not installed", windowsServiceName)
return fmt.Errorf("service %s is not installed", windowsServiceName)
}
defer s.Close()
err = s.Delete()
if err != nil {
logger.Errorf("Cannot delete service %s", windowsServiceName)
return err
}
logger.Infof("Argo Tunnel agent service is uninstalled")
err = eventlog.Remove(windowsServiceName)
if err != nil {
logger.Errorf("Cannot remove event logger")
return fmt.Errorf("RemoveEventLogSource() failed: %s", err)
}
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)))
}