summaryrefslogtreecommitdiff
path: root/vendor/github.com/godbus/dbus/export.go
blob: 95d0e29582d44bf4200c182ebe943369fb5a95e7 (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
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
package dbus

import (
	"errors"
	"fmt"
	"reflect"
	"strings"
)

var (
	ErrMsgInvalidArg = Error{
		"org.freedesktop.DBus.Error.InvalidArgs",
		[]interface{}{"Invalid type / number of args"},
	}
	ErrMsgNoObject = Error{
		"org.freedesktop.DBus.Error.NoSuchObject",
		[]interface{}{"No such object"},
	}
	ErrMsgUnknownMethod = Error{
		"org.freedesktop.DBus.Error.UnknownMethod",
		[]interface{}{"Unknown / invalid method"},
	}
	ErrMsgUnknownInterface = Error{
		"org.freedesktop.DBus.Error.UnknownInterface",
		[]interface{}{"Object does not implement the interface"},
	}
)

func MakeFailedError(err error) *Error {
	return &Error{
		"org.freedesktop.DBus.Error.Failed",
		[]interface{}{err.Error()},
	}
}

// Sender is a type which can be used in exported methods to receive the message
// sender.
type Sender string

func computeMethodName(name string, mapping map[string]string) string {
	newname, ok := mapping[name]
	if ok {
		name = newname
	}
	return name
}

func getMethods(in interface{}, mapping map[string]string) map[string]reflect.Value {
	if in == nil {
		return nil
	}
	methods := make(map[string]reflect.Value)
	val := reflect.ValueOf(in)
	typ := val.Type()
	for i := 0; i < typ.NumMethod(); i++ {
		methtype := typ.Method(i)
		method := val.Method(i)
		t := method.Type()
		// only track valid methods must return *Error as last arg
		// and must be exported
		if t.NumOut() == 0 ||
			t.Out(t.NumOut()-1) != reflect.TypeOf(&ErrMsgInvalidArg) ||
			methtype.PkgPath != "" {
			continue
		}
		// map names while building table
		methods[computeMethodName(methtype.Name, mapping)] = method
	}
	return methods
}

func standardMethodArgumentDecode(m Method, sender string, msg *Message, body []interface{}) ([]interface{}, error) {
	pointers := make([]interface{}, m.NumArguments())
	decode := make([]interface{}, 0, len(body))

	for i := 0; i < m.NumArguments(); i++ {
		tp := reflect.TypeOf(m.ArgumentValue(i))
		val := reflect.New(tp)
		pointers[i] = val.Interface()
		if tp == reflect.TypeOf((*Sender)(nil)).Elem() {
			val.Elem().SetString(sender)
		} else if tp == reflect.TypeOf((*Message)(nil)).Elem() {
			val.Elem().Set(reflect.ValueOf(*msg))
		} else {
			decode = append(decode, pointers[i])
		}
	}

	if len(decode) != len(body) {
		return nil, ErrMsgInvalidArg
	}

	if err := Store(body, decode...); err != nil {
		return nil, ErrMsgInvalidArg
	}

	return pointers, nil
}

func (conn *Conn) decodeArguments(m Method, sender string, msg *Message) ([]interface{}, error) {
	if decoder, ok := m.(ArgumentDecoder); ok {
		return decoder.DecodeArguments(conn, sender, msg, msg.Body)
	}
	return standardMethodArgumentDecode(m, sender, msg, msg.Body)
}

// handleCall handles the given method call (i.e. looks if it's one of the
// pre-implemented ones and searches for a corresponding handler if not).
func (conn *Conn) handleCall(msg *Message) {
	name := msg.Headers[FieldMember].value.(string)
	path := msg.Headers[FieldPath].value.(ObjectPath)
	ifaceName, _ := msg.Headers[FieldInterface].value.(string)
	sender, hasSender := msg.Headers[FieldSender].value.(string)
	serial := msg.serial
	if ifaceName == "org.freedesktop.DBus.Peer" {
		switch name {
		case "Ping":
			conn.sendReply(sender, serial)
		case "GetMachineId":
			conn.sendReply(sender, serial, conn.uuid)
		default:
			conn.sendError(ErrMsgUnknownMethod, sender, serial)
		}
		return
	}
	if len(name) == 0 {
		conn.sendError(ErrMsgUnknownMethod, sender, serial)
	}

	object, ok := conn.handler.LookupObject(path)
	if !ok {
		conn.sendError(ErrMsgNoObject, sender, serial)
		return
	}

	iface, exists := object.LookupInterface(ifaceName)
	if !exists {
		conn.sendError(ErrMsgUnknownInterface, sender, serial)
		return
	}

	m, exists := iface.LookupMethod(name)
	if !exists {
		conn.sendError(ErrMsgUnknownMethod, sender, serial)
		return
	}
	args, err := conn.decodeArguments(m, sender, msg)
	if err != nil {
		conn.sendError(err, sender, serial)
		return
	}

	ret, err := m.Call(args...)
	if err != nil {
		conn.sendError(err, sender, serial)
		return
	}

	if msg.Flags&FlagNoReplyExpected == 0 {
		reply := new(Message)
		reply.Type = TypeMethodReply
		reply.serial = conn.getSerial()
		reply.Headers = make(map[HeaderField]Variant)
		if hasSender {
			reply.Headers[FieldDestination] = msg.Headers[FieldSender]
		}
		reply.Headers[FieldReplySerial] = MakeVariant(msg.serial)
		reply.Body = make([]interface{}, len(ret))
		for i := 0; i < len(ret); i++ {
			reply.Body[i] = ret[i]
		}
		reply.Headers[FieldSignature] = MakeVariant(SignatureOf(reply.Body...))

		conn.sendMessage(reply)
	}
}

// Emit emits the given signal on the message bus. The name parameter must be
// formatted as "interface.member", e.g., "org.freedesktop.DBus.NameLost".
func (conn *Conn) Emit(path ObjectPath, name string, values ...interface{}) error {
	if !path.IsValid() {
		return errors.New("dbus: invalid object path")
	}
	i := strings.LastIndex(name, ".")
	if i == -1 {
		return errors.New("dbus: invalid method name")
	}
	iface := name[:i]
	member := name[i+1:]
	if !isValidMember(member) {
		return errors.New("dbus: invalid method name")
	}
	if !isValidInterface(iface) {
		return errors.New("dbus: invalid interface name")
	}
	msg := new(Message)
	msg.Type = TypeSignal
	msg.serial = conn.getSerial()
	msg.Headers = make(map[HeaderField]Variant)
	msg.Headers[FieldInterface] = MakeVariant(iface)
	msg.Headers[FieldMember] = MakeVariant(member)
	msg.Headers[FieldPath] = MakeVariant(path)
	msg.Body = values
	if len(values) > 0 {
		msg.Headers[FieldSignature] = MakeVariant(SignatureOf(values...))
	}

	var closed bool
	conn.sendMessageAndIfClosed(msg, func() {
		closed = true
	})
	if closed {
		return ErrClosed
	}
	return nil
}

// Export registers the given value to be exported as an object on the
// message bus.
//
// If a method call on the given path and interface is received, an exported
// method with the same name is called with v as the receiver if the
// parameters match and the last return value is of type *Error. If this
// *Error is not nil, it is sent back to the caller as an error.
// Otherwise, a method reply is sent with the other return values as its body.
//
// Any parameters with the special type Sender are set to the sender of the
// dbus message when the method is called. Parameters of this type do not
// contribute to the dbus signature of the method (i.e. the method is exposed
// as if the parameters of type Sender were not there).
//
// Similarly, any parameters with the type Message are set to the raw message
// received on the bus. Again, parameters of this type do not contribute to the
// dbus signature of the method.
//
// Every method call is executed in a new goroutine, so the method may be called
// in multiple goroutines at once.
//
// Method calls on the interface org.freedesktop.DBus.Peer will be automatically
// handled for every object.
//
// Passing nil as the first parameter will cause conn to cease handling calls on
// the given combination of path and interface.
//
// Export returns an error if path is not a valid path name.
func (conn *Conn) Export(v interface{}, path ObjectPath, iface string) error {
	return conn.ExportWithMap(v, nil, path, iface)
}

// ExportWithMap works exactly like Export but provides the ability to remap
// method names (e.g. export a lower-case method).
//
// The keys in the map are the real method names (exported on the struct), and
// the values are the method names to be exported on DBus.
func (conn *Conn) ExportWithMap(v interface{}, mapping map[string]string, path ObjectPath, iface string) error {
	return conn.export(getMethods(v, mapping), path, iface, false)
}

// ExportSubtree works exactly like Export but registers the given value for
// an entire subtree rather under the root path provided.
//
// In order to make this useful, one parameter in each of the value's exported
// methods should be a Message, in which case it will contain the raw message
// (allowing one to get access to the path that caused the method to be called).
//
// Note that more specific export paths take precedence over less specific. For
// example, a method call using the ObjectPath /foo/bar/baz will call a method
// exported on /foo/bar before a method exported on /foo.
func (conn *Conn) ExportSubtree(v interface{}, path ObjectPath, iface string) error {
	return conn.ExportSubtreeWithMap(v, nil, path, iface)
}

// ExportSubtreeWithMap works exactly like ExportSubtree but provides the
// ability to remap method names (e.g. export a lower-case method).
//
// The keys in the map are the real method names (exported on the struct), and
// the values are the method names to be exported on DBus.
func (conn *Conn) ExportSubtreeWithMap(v interface{}, mapping map[string]string, path ObjectPath, iface string) error {
	return conn.export(getMethods(v, mapping), path, iface, true)
}

// ExportMethodTable like Export registers the given methods as an object
// on the message bus. Unlike Export the it uses a method table to define
// the object instead of a native go object.
//
// The method table is a map from method name to function closure
// representing the method. This allows an object exported on the bus to not
// necessarily be a native go object. It can be useful for generating exposed
// methods on the fly.
//
// Any non-function objects in the method table are ignored.
func (conn *Conn) ExportMethodTable(methods map[string]interface{}, path ObjectPath, iface string) error {
	return conn.exportMethodTable(methods, path, iface, false)
}

// Like ExportSubtree, but with the same caveats as ExportMethodTable.
func (conn *Conn) ExportSubtreeMethodTable(methods map[string]interface{}, path ObjectPath, iface string) error {
	return conn.exportMethodTable(methods, path, iface, true)
}

func (conn *Conn) exportMethodTable(methods map[string]interface{}, path ObjectPath, iface string, includeSubtree bool) error {
	out := make(map[string]reflect.Value)
	for name, method := range methods {
		rval := reflect.ValueOf(method)
		if rval.Kind() != reflect.Func {
			continue
		}
		t := rval.Type()
		// only track valid methods must return *Error as last arg
		if t.NumOut() == 0 ||
			t.Out(t.NumOut()-1) != reflect.TypeOf(&ErrMsgInvalidArg) {
			continue
		}
		out[name] = rval
	}
	return conn.export(out, path, iface, includeSubtree)
}

func (conn *Conn) unexport(h *defaultHandler, path ObjectPath, iface string) error {
	if h.PathExists(path) {
		obj := h.objects[path]
		obj.DeleteInterface(iface)
		if len(obj.interfaces) == 0 {
			h.DeleteObject(path)
		}
	}
	return nil
}

// exportWithMap is the worker function for all exports/registrations.
func (conn *Conn) export(methods map[string]reflect.Value, path ObjectPath, iface string, includeSubtree bool) error {
	h, ok := conn.handler.(*defaultHandler)
	if !ok {
		return fmt.Errorf(
			`dbus: export only allowed on the default hander handler have %T"`,
			conn.handler)
	}

	if !path.IsValid() {
		return fmt.Errorf(`dbus: Invalid path name: "%s"`, path)
	}

	// Remove a previous export if the interface is nil
	if methods == nil {
		return conn.unexport(h, path, iface)
	}

	// If this is the first handler for this path, make a new map to hold all
	// handlers for this path.
	if !h.PathExists(path) {
		h.AddObject(path, newExportedObject())
	}

	exportedMethods := make(map[string]Method)
	for name, method := range methods {
		exportedMethods[name] = exportedMethod{method}
	}

	// Finally, save this handler
	obj := h.objects[path]
	obj.AddInterface(iface, newExportedIntf(exportedMethods, includeSubtree))

	return nil
}

// ReleaseName calls org.freedesktop.DBus.ReleaseName and awaits a response.
func (conn *Conn) ReleaseName(name string) (ReleaseNameReply, error) {
	var r uint32
	err := conn.busObj.Call("org.freedesktop.DBus.ReleaseName", 0, name).Store(&r)
	if err != nil {
		return 0, err
	}
	return ReleaseNameReply(r), nil
}

// RequestName calls org.freedesktop.DBus.RequestName and awaits a response.
func (conn *Conn) RequestName(name string, flags RequestNameFlags) (RequestNameReply, error) {
	var r uint32
	err := conn.busObj.Call("org.freedesktop.DBus.RequestName", 0, name, flags).Store(&r)
	if err != nil {
		return 0, err
	}
	return RequestNameReply(r), nil
}

// ReleaseNameReply is the reply to a ReleaseName call.
type ReleaseNameReply uint32

const (
	ReleaseNameReplyReleased ReleaseNameReply = 1 + iota
	ReleaseNameReplyNonExistent
	ReleaseNameReplyNotOwner
)

// RequestNameFlags represents the possible flags for a RequestName call.
type RequestNameFlags uint32

const (
	NameFlagAllowReplacement RequestNameFlags = 1 << iota
	NameFlagReplaceExisting
	NameFlagDoNotQueue
)

// RequestNameReply is the reply to a RequestName call.
type RequestNameReply uint32

const (
	RequestNameReplyPrimaryOwner RequestNameReply = 1 + iota
	RequestNameReplyInQueue
	RequestNameReplyExists
	RequestNameReplyAlreadyOwner
)