// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build windows
// Package svc provides everything required to build Windows service.
package svc
import (
"errors"
"sync"
"unsafe"
"golang.org/x/sys/windows"
)
// State describes service execution state (Stopped, Running and so on).
type State uint32
const (
Stopped = State(windows.SERVICE_STOPPED)
StartPending = State(windows.SERVICE_START_PENDING)
StopPending = State(windows.SERVICE_STOP_PENDING)
Running = State(windows.SERVICE_RUNNING)
ContinuePending = State(windows.SERVICE_CONTINUE_PENDING)
PausePending = State(windows.SERVICE_PAUSE_PENDING)
Paused = State(windows.SERVICE_PAUSED)
)
// Cmd represents service state change request. It is sent to a service
// by the service manager, and should be actioned upon by the service.
type Cmd uint32
const (
Stop = Cmd(windows.SERVICE_CONTROL_STOP)
Pause = Cmd(windows.SERVICE_CONTROL_PAUSE)
Continue = Cmd(windows.SERVICE_CONTROL_CONTINUE)
Interrogate = Cmd(windows.SERVICE_CONTROL_INTERROGATE)
Shutdown = Cmd(windows.SERVICE_CONTROL_SHUTDOWN)
ParamChange = Cmd(windows.SERVICE_CONTROL_PARAMCHANGE)
NetBindAdd = Cmd(windows.SERVICE_CONTROL_NETBINDADD)
NetBindRemove = Cmd(windows.SERVICE_CONTROL_NETBINDREMOVE)
NetBindEnable = Cmd(windows.SERVICE_CONTROL_NETBINDENABLE)
NetBindDisable = Cmd(windows.SERVICE_CONTROL_NETBINDDISABLE)
DeviceEvent = Cmd(windows.SERVICE_CONTROL_DEVICEEVENT)
HardwareProfileChange = Cmd(windows.SERVICE_CONTROL_HARDWAREPROFILECHANGE)
PowerEvent = Cmd(windows.SERVICE_CONTROL_POWEREVENT)
SessionChange = Cmd(windows.SERVICE_CONTROL_SESSIONCHANGE)
PreShutdown = Cmd(windows.SERVICE_CONTROL_PRESHUTDOWN)
)
// Accepted is used to describe commands accepted by the service.
// Note that Interrogate is always accepted.
type Accepted uint32
const (
AcceptStop = Accepted(windows.SERVICE_ACCEPT_STOP)
AcceptShutdown = Accepted(windows.SERVICE_ACCEPT_SHUTDOWN)
AcceptPauseAndContinue = Accepted(windows.SERVICE_ACCEPT_PAUSE_CONTINUE)
AcceptParamChange = Accepted(windows.SERVICE_ACCEPT_PARAMCHANGE)
AcceptNetBindChange = Accepted(windows.SERVICE_ACCEPT_NETBINDCHANGE)
AcceptHardwareProfileChange = Accepted(windows.SERVICE_ACCEPT_HARDWAREPROFILECHANGE)
AcceptPowerEvent = Accepted(windows.SERVICE_ACCEPT_POWEREVENT)
AcceptSessionChange = Accepted(windows.SERVICE_ACCEPT_SESSIONCHANGE)
AcceptPreShutdown = Accepted(windows.SERVICE_ACCEPT_PRESHUTDOWN)
)
// ActivityStatus allows for services to be selected based on active and inactive categories of service state.
type ActivityStatus uint32
const (
Active = ActivityStatus(windows.SERVICE_ACTIVE)
Inactive = ActivityStatus(windows.SERVICE_INACTIVE)
AnyActivity = ActivityStatus(windows.SERVICE_STATE_ALL)
)
// Status combines State and Accepted commands to fully describe running service.
type Status struct {
State State
Accepts Accepted
CheckPoint uint32 // used to report progress during a lengthy operation
WaitHint uint32 // estimated time required for a pending operation, in milliseconds
ProcessId uint32 // if the service is running, the process identifier of it, and otherwise zero
Win32ExitCode uint32 // set if the service has exited with a win32 exit code
ServiceSpecificExitCode uint32 // set if the service has exited with a service-specific exit code
}
// StartReason is the reason that the service was started.
type StartReason uint32
const (
StartReasonDemand = StartReason(windows.SERVICE_START_REASON_DEMAND)
StartReasonAuto = StartReason(windows.SERVICE_START_REASON_AUTO)
StartReasonTrigger = StartReason(windows.SERVICE_START_REASON_TRIGGER)
StartReasonRestartOnFailure = StartReason(windows.SERVICE_START_REASON_RESTART_ON_FAILURE)
StartReasonDelayedAuto = StartReason(windows.SERVICE_START_REASON_DELAYEDAUTO)
)
// ChangeRequest is sent to the service Handler to request service status change.
type ChangeRequest struct {
Cmd Cmd
EventType uint32
EventData uintptr
CurrentStatus Status
Context uintptr
}
// Handler is the interface that must be implemented to build Windows service.
type Handler interface {
// Execute will be called by the package code at the start of
// the service, and the service will exit once Execute completes.
// Inside Execute you must read service change requests from r and
// act accordingly. You must keep service control manager up to date
// about state of your service by writing into s as required.
// args contains service name followed by argument strings passed
// to the service.
// You can provide service exit code in exitCode return parameter,
// with 0 being "no error". You can also indicate if exit code,
// if any, is service specific or not by using svcSpecificEC
// parameter.
Execute(args []string, r <-chan ChangeRequest, s chan<- Status) (svcSpecificEC bool, exitCode uint32)
}
type ctlEvent struct {
cmd Cmd
eventType uint32
eventData uintptr
context uintptr
errno uint32
}
// service provides access to windows service api.
type service struct {
name string
h windows.Handle
c chan ctlEvent
handler Handler
}
type exitCode struct {
isSvcSpecific bool
errno uint32
}
func (s *service) updateStatus(status *Status, ec *exitCode) error {
if s.h == 0 {
return errors.New("updateStatus with no service status handle")
}
var t windows.SERVICE_STATUS
t.ServiceType = windows.SERVICE_WIN32_OWN_PROCESS
t.CurrentState = uint32(status.State)
if status.Accepts&AcceptStop != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_STOP
}
if status.Accepts&AcceptShutdown != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_SHUTDOWN
}
if status.Accepts&AcceptPauseAndContinue != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_PAUSE_CONTINUE
}
if status.Accepts&AcceptParamChange != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_PARAMCHANGE
}
if status.Accepts&AcceptNetBindChange != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_NETBINDCHANGE
}
if status.Accepts&AcceptHardwareProfileChange != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_HARDWAREPROFILECHANGE
}
if status.Accepts&AcceptPowerEvent != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_POWEREVENT
}
if status.Accepts&AcceptSessionChange != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_SESSIONCHANGE
}
if status.Accepts&AcceptPreShutdown != 0 {
t.ControlsAccepted |= windows.SERVICE_ACCEPT_PRESHUTDOWN
}
if ec.errno == 0 {
t.Win32ExitCode = windows.NO_ERROR
t.ServiceSpecificExitCode = windows.NO_ERROR
} else if ec.isSvcSpecific {
t.Win32ExitCode = uint32(windows.ERROR_SERVICE_SPECIFIC_ERROR)
t.ServiceSpecificExitCode = ec.errno
} else {
t.Win32ExitCode = ec.errno
t.ServiceSpecificExitCode = windows.NO_ERROR
}
t.CheckPoint = status.CheckPoint
t.WaitHint = status.WaitHint
return windows.SetServiceStatus(s.h, &t)
}
var (
initCallbacks sync.Once
ctlHandlerCallback uintptr
serviceMainCallback uintptr
)
func ctlHandler(ctl, evtype, evdata, context uintptr) uintptr {
e := ctlEvent{cmd: Cmd(ctl), eventType: uint32(evtype), eventData: evdata, context: 123456} // Set context to 123456 to test issue #25660.
theService.c <- e
return 0
}
var theService service // This is, unfortunately, a global, which means only one service per process.
// serviceMain is the entry point called by the service manager, registered earlier by
// the call to StartServiceCtrlDispatcher.
func serviceMain(argc uint32, argv **uint16) uintptr {
handle, err := windows.RegisterServiceCtrlHandlerEx(windows.StringToUTF16Ptr(theService.name), ctlHandlerCallback, 0)
if sysErr, ok := err.(windows.Errno); ok {
return uintptr(sysErr)
} else if err != nil {
return uintptr(windows.ERROR_UNKNOWN_EXCEPTION)
}
theService.h = handle
defer func() {
theService.h = 0
}()
args16 := unsafe.Slice(argv, int(argc))
args := make([]string, len(args16))
for i, a := range args16 {
args[i] = windows.UTF16PtrToString(a)
}
cmdsToHandler := make(chan ChangeRequest)
changesFromHandler := make(chan Status)
exitFromHandler := make(chan exitCode)
go func() {
ss, errno := theService.handler.Execute(args, cmdsToHandler, changesFromHandler)
exitFromHandler <- exitCode{ss, errno}
}()
ec := exitCode{isSvcSpecific: true, errno: 0}
outcr := ChangeRequest{
CurrentStatus: Status{State: Stopped},
}
var outch chan ChangeRequest
inch := theService.c
loop:
for {
select {
case r := <-inch:
if r.errno != 0 {
ec.errno = r.errno
break loop
}
inch = nil
outch = cmdsToHandler
outcr.Cmd = r.cmd
outcr.EventType = r.eventType
outcr.EventData = r.eventData
outcr.Context = r.context
case outch <- outcr:
inch = theService.c
outch = nil
case c := <-changesFromHandler:
err := theService.updateStatus(&c, &ec)
if err != nil {
ec.errno = uint32(windows.ERROR_EXCEPTION_IN_SERVICE)
if err2, ok := err.(windows.Errno); ok {
ec.errno = uint32(err2)
}
break loop
}
outcr.CurrentStatus = c
case ec = <-exitFromHandler:
break loop
}
}
theService.updateStatus(&Status{State: Stopped}, &ec)
return windows.NO_ERROR
}
// Run executes service name by calling appropriate handler function.
func Run(name string, handler Handler) error {
initCallbacks.Do(func() {
ctlHandlerCallback = windows.NewCallback(ctlHandler)
serviceMainCallback = windows.NewCallback(serviceMain)
})
theService.name = name
theService.handler = handler
theService.c = make(chan ctlEvent)
t := []windows.SERVICE_TABLE_ENTRY{
{ServiceName: windows.StringToUTF16Ptr(theService.name), ServiceProc: serviceMainCallback},
{ServiceName: nil, ServiceProc: 0},
}
return windows.StartServiceCtrlDispatcher(&t[0])
}
// StatusHandle returns service status handle. It is safe to call this function
// from inside the Handler.Execute because then it is guaranteed to be set.
func StatusHandle() windows.Handle {
return theService.h
}
// DynamicStartReason returns the reason why the service was started. It is safe
// to call this function from inside the Handler.Execute because then it is
// guaranteed to be set.
func DynamicStartReason() (StartReason, error) {
var allocReason *uint32
err := windows.QueryServiceDynamicInformation(theService.h, windows.SERVICE_DYNAMIC_INFORMATION_LEVEL_START_REASON, unsafe.Pointer(&allocReason))
if err != nil {
return 0, err
}
reason := StartReason(*allocReason)
windows.LocalFree(windows.Handle(unsafe.Pointer(allocReason)))
return reason, nil
}
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