summaryrefslogtreecommitdiffstats
path: root/vendor/golang.org/x/sys/windows/svc/service.go
blob: 903cba3f1213f6d862eb683ee136a51684dbb361 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
// 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.

// +build windows

// Package svc provides everything required to build Windows service.
//
package svc

import (
	"errors"
	"runtime"
	"syscall"
	"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)
)

// 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)
)

// 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
}

// ChangeRequest is sent to the service Handler to request service status change.
type ChangeRequest struct {
	Cmd           Cmd
	EventType     uint32
	EventData     uintptr
	CurrentStatus Status
}

// 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)
}

var (
	// These are used by asm code.
	goWaitsH                       uintptr
	cWaitsH                        uintptr
	ssHandle                       uintptr
	sName                          *uint16
	sArgc                          uintptr
	sArgv                          **uint16
	ctlHandlerExProc               uintptr
	cSetEvent                      uintptr
	cWaitForSingleObject           uintptr
	cRegisterServiceCtrlHandlerExW uintptr
)

func init() {
	k := syscall.MustLoadDLL("kernel32.dll")
	cSetEvent = k.MustFindProc("SetEvent").Addr()
	cWaitForSingleObject = k.MustFindProc("WaitForSingleObject").Addr()
	a := syscall.MustLoadDLL("advapi32.dll")
	cRegisterServiceCtrlHandlerExW = a.MustFindProc("RegisterServiceCtrlHandlerExW").Addr()
}

// The HandlerEx prototype also has a context pointer but since we don't use
// it at start-up time we don't have to pass it over either.
type ctlEvent struct {
	cmd       Cmd
	eventType uint32
	eventData uintptr
	errno     uint32
}

// service provides access to windows service api.
type service struct {
	name    string
	h       windows.Handle
	cWaits  *event
	goWaits *event
	c       chan ctlEvent
	handler Handler
}

func newService(name string, handler Handler) (*service, error) {
	var s service
	var err error
	s.name = name
	s.c = make(chan ctlEvent)
	s.handler = handler
	s.cWaits, err = newEvent()
	if err != nil {
		return nil, err
	}
	s.goWaits, err = newEvent()
	if err != nil {
		s.cWaits.Close()
		return nil, err
	}
	return &s, nil
}

func (s *service) close() error {
	s.cWaits.Close()
	s.goWaits.Close()
	return nil
}

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 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)
}

const (
	sysErrSetServiceStatusFailed = uint32(syscall.APPLICATION_ERROR) + iota
	sysErrNewThreadInCallback
)

func (s *service) run() {
	s.goWaits.Wait()
	s.h = windows.Handle(ssHandle)
	argv := (*[100]*int16)(unsafe.Pointer(sArgv))[:sArgc]
	args := make([]string, len(argv))
	for i, a := range argv {
		args[i] = syscall.UTF16ToString((*[1 << 20]uint16)(unsafe.Pointer(a))[:])
	}

	cmdsToHandler := make(chan ChangeRequest)
	changesFromHandler := make(chan Status)
	exitFromHandler := make(chan exitCode)

	go func() {
		ss, errno := s.handler.Execute(args, cmdsToHandler, changesFromHandler)
		exitFromHandler <- exitCode{ss, errno}
	}()

	status := Status{State: Stopped}
	ec := exitCode{isSvcSpecific: true, errno: 0}
	var outch chan ChangeRequest
	inch := s.c
	var cmd Cmd
	var evtype uint32
	var evdata uintptr
loop:
	for {
		select {
		case r := <-inch:
			if r.errno != 0 {
				ec.errno = r.errno
				break loop
			}
			inch = nil
			outch = cmdsToHandler
			cmd = r.cmd
			evtype = r.eventType
			evdata = r.eventData
		case outch <- ChangeRequest{cmd, evtype, evdata, status}:
			inch = s.c
			outch = nil
		case c := <-changesFromHandler:
			err := s.updateStatus(&c, &ec)
			if err != nil {
				// best suitable error number
				ec.errno = sysErrSetServiceStatusFailed
				if err2, ok := err.(syscall.Errno); ok {
					ec.errno = uint32(err2)
				}
				break loop
			}
			status = c
		case ec = <-exitFromHandler:
			break loop
		}
	}

	s.updateStatus(&Status{State: Stopped}, &ec)
	s.cWaits.Set()
}

func newCallback(fn interface{}) (cb uintptr, err error) {
	defer func() {
		r := recover()
		if r == nil {
			return
		}
		cb = 0
		switch v := r.(type) {
		case string:
			err = errors.New(v)
		case error:
			err = v
		default:
			err = errors.New("unexpected panic in syscall.NewCallback")
		}
	}()
	return syscall.NewCallback(fn), nil
}

// BUG(brainman): There is no mechanism to run multiple services
// inside one single executable. Perhaps, it can be overcome by
// using RegisterServiceCtrlHandlerEx Windows api.

// Run executes service name by calling appropriate handler function.
func Run(name string, handler Handler) error {
	runtime.LockOSThread()

	tid := windows.GetCurrentThreadId()

	s, err := newService(name, handler)
	if err != nil {
		return err
	}

	ctlHandler := func(ctl uint32, evtype uint32, evdata uintptr, context uintptr) uintptr {
		e := ctlEvent{cmd: Cmd(ctl), eventType: evtype, eventData: evdata}
		// We assume that this callback function is running on
		// the same thread as Run. Nowhere in MS documentation
		// I could find statement to guarantee that. So putting
		// check here to verify, otherwise things will go bad
		// quickly, if ignored.
		i := windows.GetCurrentThreadId()
		if i != tid {
			e.errno = sysErrNewThreadInCallback
		}
		s.c <- e
		// Always return NO_ERROR (0) for now.
		return 0
	}

	var svcmain uintptr
	getServiceMain(&svcmain)
	t := []windows.SERVICE_TABLE_ENTRY{
		{syscall.StringToUTF16Ptr(s.name), svcmain},
		{nil, 0},
	}

	goWaitsH = uintptr(s.goWaits.h)
	cWaitsH = uintptr(s.cWaits.h)
	sName = t[0].ServiceName
	ctlHandlerExProc, err = newCallback(ctlHandler)
	if err != nil {
		return err
	}

	go s.run()

	err = windows.StartServiceCtrlDispatcher(&t[0])
	if err != nil {
		return err
	}
	return nil
}

// 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.
// This code will have to change once multiple services are possible per process.
func StatusHandle() windows.Handle {
	return windows.Handle(ssHandle)
}