// 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 mgr can be used to manage Windows service programs.
// It can be used to install and remove them. It can also start,
// stop and pause them. The package can query / change current
// service state and config parameters.
package mgr
import (
"syscall"
"time"
"unicode/utf16"
"unsafe"
"golang.org/x/sys/windows"
)
// Mgr is used to manage Windows service.
type Mgr struct {
Handle windows.Handle
}
// Connect establishes a connection to the service control manager.
func Connect() (*Mgr, error) {
return ConnectRemote("")
}
// ConnectRemote establishes a connection to the
// service control manager on computer named host.
func ConnectRemote(host string) (*Mgr, error) {
var s *uint16
if host != "" {
s = syscall.StringToUTF16Ptr(host)
}
h, err := windows.OpenSCManager(s, nil, windows.SC_MANAGER_ALL_ACCESS)
if err != nil {
return nil, err
}
return &Mgr{Handle: h}, nil
}
// Disconnect closes connection to the service control manager m.
func (m *Mgr) Disconnect() error {
return windows.CloseServiceHandle(m.Handle)
}
type LockStatus struct {
IsLocked bool // Whether the SCM has been locked.
Age time.Duration // For how long the SCM has been locked.
Owner string // The name of the user who has locked the SCM.
}
// LockStatus returns whether the service control manager is locked by
// the system, for how long, and by whom. A locked SCM indicates that
// most service actions will block until the system unlocks the SCM.
func (m *Mgr) LockStatus() (*LockStatus, error) {
bytesNeeded := uint32(unsafe.Sizeof(windows.QUERY_SERVICE_LOCK_STATUS{}) + 1024)
for {
bytes := make([]byte, bytesNeeded)
lockStatus := (*windows.QUERY_SERVICE_LOCK_STATUS)(unsafe.Pointer(&bytes[0]))
err := windows.QueryServiceLockStatus(m.Handle, lockStatus, uint32(len(bytes)), &bytesNeeded)
if err == windows.ERROR_INSUFFICIENT_BUFFER && bytesNeeded >= uint32(unsafe.Sizeof(windows.QUERY_SERVICE_LOCK_STATUS{})) {
continue
}
if err != nil {
return nil, err
}
status := &LockStatus{
IsLocked: lockStatus.IsLocked != 0,
Age: time.Duration(lockStatus.LockDuration) * time.Second,
Owner: windows.UTF16PtrToString(lockStatus.LockOwner),
}
return status, nil
}
}
func toPtr(s string) *uint16 {
if len(s) == 0 {
return nil
}
return syscall.StringToUTF16Ptr(s)
}
// toStringBlock terminates strings in ss with 0, and then
// concatenates them together. It also adds extra 0 at the end.
func toStringBlock(ss []string) *uint16 {
if len(ss) == 0 {
return nil
}
t := ""
for _, s := range ss {
if s != "" {
t += s + "\x00"
}
}
if t == "" {
return nil
}
t += "\x00"
return &utf16.Encode([]rune(t))[0]
}
// CreateService installs new service name on the system.
// The service will be executed by running exepath binary.
// Use config c to specify service parameters.
// Any args will be passed as command-line arguments when
// the service is started; these arguments are distinct from
// the arguments passed to Service.Start or via the "Start
// parameters" field in the service's Properties dialog box.
func (m *Mgr) CreateService(name, exepath string, c Config, args ...string) (*Service, error) {
if c.StartType == 0 {
c.StartType = StartManual
}
if c.ServiceType == 0 {
c.ServiceType = windows.SERVICE_WIN32_OWN_PROCESS
}
s := syscall.EscapeArg(exepath)
for _, v := range args {
s += " " + syscall.EscapeArg(v)
}
h, err := windows.CreateService(m.Handle, toPtr(name), toPtr(c.DisplayName),
windows.SERVICE_ALL_ACCESS, c.ServiceType,
c.StartType, c.ErrorControl, toPtr(s), toPtr(c.LoadOrderGroup),
nil, toStringBlock(c.Dependencies), toPtr(c.ServiceStartName), toPtr(c.Password))
if err != nil {
return nil, err
}
if c.SidType != windows.SERVICE_SID_TYPE_NONE {
err = updateSidType(h, c.SidType)
if err != nil {
windows.DeleteService(h)
windows.CloseServiceHandle(h)
return nil, err
}
}
if c.Description != "" {
err = updateDescription(h, c.Description)
if err != nil {
windows.DeleteService(h)
windows.CloseServiceHandle(h)
return nil, err
}
}
if c.DelayedAutoStart {
err = updateStartUp(h, c.DelayedAutoStart)
if err != nil {
windows.DeleteService(h)
windows.CloseServiceHandle(h)
return nil, err
}
}
return &Service{Name: name, Handle: h}, nil
}
// OpenService retrieves access to service name, so it can
// be interrogated and controlled.
func (m *Mgr) OpenService(name string) (*Service, error) {
h, err := windows.OpenService(m.Handle, syscall.StringToUTF16Ptr(name), windows.SERVICE_ALL_ACCESS)
if err != nil {
return nil, err
}
return &Service{Name: name, Handle: h}, nil
}
// ListServices enumerates services in the specified
// service control manager database m.
// If the caller does not have the SERVICE_QUERY_STATUS
// access right to a service, the service is silently
// omitted from the list of services returned.
func (m *Mgr) ListServices() ([]string, error) {
var err error
var bytesNeeded, servicesReturned uint32
var buf []byte
for {
var p *byte
if len(buf) > 0 {
p = &buf[0]
}
err = windows.EnumServicesStatusEx(m.Handle, windows.SC_ENUM_PROCESS_INFO,
windows.SERVICE_WIN32, windows.SERVICE_STATE_ALL,
p, uint32(len(buf)), &bytesNeeded, &servicesReturned, nil, nil)
if err == nil {
break
}
if err != syscall.ERROR_MORE_DATA {
return nil, err
}
if bytesNeeded <= uint32(len(buf)) {
return nil, err
}
buf = make([]byte, bytesNeeded)
}
if servicesReturned == 0 {
return nil, nil
}
services := unsafe.Slice((*windows.ENUM_SERVICE_STATUS_PROCESS)(unsafe.Pointer(&buf[0])), int(servicesReturned))
var names []string
for _, s := range services {
name := windows.UTF16PtrToString(s.ServiceName)
names = append(names, name)
}
return names, nil
}
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