412 lines
12 KiB
Go
412 lines
12 KiB
Go
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package dbus
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import (
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"errors"
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"fmt"
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"reflect"
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"strings"
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)
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var (
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errmsgInvalidArg = Error{
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"org.freedesktop.DBus.Error.InvalidArgs",
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[]interface{}{"Invalid type / number of args"},
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}
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errmsgNoObject = Error{
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"org.freedesktop.DBus.Error.NoSuchObject",
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[]interface{}{"No such object"},
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}
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errmsgUnknownMethod = Error{
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"org.freedesktop.DBus.Error.UnknownMethod",
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[]interface{}{"Unknown / invalid method"},
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}
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)
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// exportWithMapping represents an exported struct along with a method name
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// mapping to allow for exporting lower-case methods, etc.
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type exportWithMapping struct {
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export interface{}
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// Method name mapping; key -> struct method, value -> dbus method.
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mapping map[string]string
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// Whether or not this export is for the entire subtree
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includeSubtree bool
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}
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// Sender is a type which can be used in exported methods to receive the message
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// sender.
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type Sender string
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func exportedMethod(export exportWithMapping, name string) reflect.Value {
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if export.export == nil {
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return reflect.Value{}
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}
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// If a mapping was included in the export, check the map to see if we
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// should be looking for a different method in the export.
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if export.mapping != nil {
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for key, value := range export.mapping {
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if value == name {
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name = key
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break
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}
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// Catch the case where a method is aliased but the client is calling
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// the original, e.g. the "Foo" method was exported mapped to
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// "foo," and dbus client called the original "Foo."
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if key == name {
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return reflect.Value{}
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}
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}
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}
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value := reflect.ValueOf(export.export)
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m := value.MethodByName(name)
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// Catch the case of attempting to call an unexported method
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method, ok := value.Type().MethodByName(name)
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if !m.IsValid() || !ok || method.PkgPath != "" {
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return reflect.Value{}
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}
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t := m.Type()
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if t.NumOut() == 0 ||
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t.Out(t.NumOut()-1) != reflect.TypeOf(&errmsgInvalidArg) {
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return reflect.Value{}
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}
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return m
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}
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// searchHandlers will look through all registered handlers looking for one
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// to handle the given path. If a verbatim one isn't found, it will check for
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// a subtree registration for the path as well.
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func (conn *Conn) searchHandlers(path ObjectPath) (map[string]exportWithMapping, bool) {
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conn.handlersLck.RLock()
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defer conn.handlersLck.RUnlock()
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handlers, ok := conn.handlers[path]
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if ok {
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return handlers, ok
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}
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// If handlers weren't found for this exact path, look for a matching subtree
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// registration
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handlers = make(map[string]exportWithMapping)
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path = path[:strings.LastIndex(string(path), "/")]
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for len(path) > 0 {
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var subtreeHandlers map[string]exportWithMapping
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subtreeHandlers, ok = conn.handlers[path]
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if ok {
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for iface, handler := range subtreeHandlers {
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// Only include this handler if it registered for the subtree
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if handler.includeSubtree {
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handlers[iface] = handler
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}
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}
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break
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}
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path = path[:strings.LastIndex(string(path), "/")]
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}
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return handlers, ok
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}
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// handleCall handles the given method call (i.e. looks if it's one of the
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// pre-implemented ones and searches for a corresponding handler if not).
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func (conn *Conn) handleCall(msg *Message) {
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name := msg.Headers[FieldMember].value.(string)
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path := msg.Headers[FieldPath].value.(ObjectPath)
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ifaceName, hasIface := msg.Headers[FieldInterface].value.(string)
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sender, hasSender := msg.Headers[FieldSender].value.(string)
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serial := msg.serial
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if ifaceName == "org.freedesktop.DBus.Peer" {
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switch name {
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case "Ping":
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conn.sendReply(sender, serial)
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case "GetMachineId":
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conn.sendReply(sender, serial, conn.uuid)
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default:
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conn.sendError(errmsgUnknownMethod, sender, serial)
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}
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return
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}
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if len(name) == 0 {
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conn.sendError(errmsgUnknownMethod, sender, serial)
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}
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// Find the exported handler (if any) for this path
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handlers, ok := conn.searchHandlers(path)
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if !ok {
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conn.sendError(errmsgNoObject, sender, serial)
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return
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}
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var m reflect.Value
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if hasIface {
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iface := handlers[ifaceName]
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m = exportedMethod(iface, name)
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} else {
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for _, v := range handlers {
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m = exportedMethod(v, name)
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if m.IsValid() {
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break
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}
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}
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}
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if !m.IsValid() {
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conn.sendError(errmsgUnknownMethod, sender, serial)
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return
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}
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t := m.Type()
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vs := msg.Body
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pointers := make([]interface{}, t.NumIn())
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decode := make([]interface{}, 0, len(vs))
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for i := 0; i < t.NumIn(); i++ {
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tp := t.In(i)
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val := reflect.New(tp)
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pointers[i] = val.Interface()
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if tp == reflect.TypeOf((*Sender)(nil)).Elem() {
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val.Elem().SetString(sender)
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} else if tp == reflect.TypeOf((*Message)(nil)).Elem() {
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val.Elem().Set(reflect.ValueOf(*msg))
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} else {
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decode = append(decode, pointers[i])
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}
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}
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if len(decode) != len(vs) {
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conn.sendError(errmsgInvalidArg, sender, serial)
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return
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}
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if err := Store(vs, decode...); err != nil {
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conn.sendError(errmsgInvalidArg, sender, serial)
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return
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}
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// Extract parameters
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params := make([]reflect.Value, len(pointers))
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for i := 0; i < len(pointers); i++ {
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params[i] = reflect.ValueOf(pointers[i]).Elem()
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}
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// Call method
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ret := m.Call(params)
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if em := ret[t.NumOut()-1].Interface().(*Error); em != nil {
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conn.sendError(*em, sender, serial)
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return
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}
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if msg.Flags&FlagNoReplyExpected == 0 {
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reply := new(Message)
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reply.Type = TypeMethodReply
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reply.serial = conn.getSerial()
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reply.Headers = make(map[HeaderField]Variant)
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if hasSender {
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reply.Headers[FieldDestination] = msg.Headers[FieldSender]
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}
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reply.Headers[FieldReplySerial] = MakeVariant(msg.serial)
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reply.Body = make([]interface{}, len(ret)-1)
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for i := 0; i < len(ret)-1; i++ {
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reply.Body[i] = ret[i].Interface()
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}
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if len(ret) != 1 {
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reply.Headers[FieldSignature] = MakeVariant(SignatureOf(reply.Body...))
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}
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conn.outLck.RLock()
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if !conn.closed {
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conn.out <- reply
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}
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conn.outLck.RUnlock()
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}
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}
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// Emit emits the given signal on the message bus. The name parameter must be
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// formatted as "interface.member", e.g., "org.freedesktop.DBus.NameLost".
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func (conn *Conn) Emit(path ObjectPath, name string, values ...interface{}) error {
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if !path.IsValid() {
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return errors.New("dbus: invalid object path")
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}
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i := strings.LastIndex(name, ".")
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if i == -1 {
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return errors.New("dbus: invalid method name")
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}
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iface := name[:i]
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member := name[i+1:]
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if !isValidMember(member) {
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return errors.New("dbus: invalid method name")
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}
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if !isValidInterface(iface) {
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return errors.New("dbus: invalid interface name")
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}
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msg := new(Message)
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msg.Type = TypeSignal
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msg.serial = conn.getSerial()
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msg.Headers = make(map[HeaderField]Variant)
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msg.Headers[FieldInterface] = MakeVariant(iface)
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msg.Headers[FieldMember] = MakeVariant(member)
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msg.Headers[FieldPath] = MakeVariant(path)
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msg.Body = values
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if len(values) > 0 {
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msg.Headers[FieldSignature] = MakeVariant(SignatureOf(values...))
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}
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conn.outLck.RLock()
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defer conn.outLck.RUnlock()
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if conn.closed {
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return ErrClosed
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}
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conn.out <- msg
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return nil
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}
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// Export registers the given value to be exported as an object on the
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// message bus.
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//
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// If a method call on the given path and interface is received, an exported
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// method with the same name is called with v as the receiver if the
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// parameters match and the last return value is of type *Error. If this
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// *Error is not nil, it is sent back to the caller as an error.
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// Otherwise, a method reply is sent with the other return values as its body.
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//
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// Any parameters with the special type Sender are set to the sender of the
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// dbus message when the method is called. Parameters of this type do not
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// contribute to the dbus signature of the method (i.e. the method is exposed
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// as if the parameters of type Sender were not there).
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//
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// Similarly, any parameters with the type Message are set to the raw message
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// received on the bus. Again, parameters of this type do not contribute to the
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// dbus signature of the method.
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//
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// Every method call is executed in a new goroutine, so the method may be called
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// in multiple goroutines at once.
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//
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// Method calls on the interface org.freedesktop.DBus.Peer will be automatically
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// handled for every object.
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//
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// Passing nil as the first parameter will cause conn to cease handling calls on
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// the given combination of path and interface.
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//
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// Export returns an error if path is not a valid path name.
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func (conn *Conn) Export(v interface{}, path ObjectPath, iface string) error {
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return conn.ExportWithMap(v, nil, path, iface)
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}
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// ExportWithMap works exactly like Export but provides the ability to remap
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// method names (e.g. export a lower-case method).
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//
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// The keys in the map are the real method names (exported on the struct), and
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// the values are the method names to be exported on DBus.
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func (conn *Conn) ExportWithMap(v interface{}, mapping map[string]string, path ObjectPath, iface string) error {
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return conn.exportWithMap(v, mapping, path, iface, false)
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}
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// ExportSubtree works exactly like Export but registers the given value for
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// an entire subtree rather under the root path provided.
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//
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// In order to make this useful, one parameter in each of the value's exported
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// methods should be a Message, in which case it will contain the raw message
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// (allowing one to get access to the path that caused the method to be called).
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//
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// Note that more specific export paths take precedence over less specific. For
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// example, a method call using the ObjectPath /foo/bar/baz will call a method
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// exported on /foo/bar before a method exported on /foo.
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func (conn *Conn) ExportSubtree(v interface{}, path ObjectPath, iface string) error {
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return conn.ExportSubtreeWithMap(v, nil, path, iface)
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}
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// ExportSubtreeWithMap works exactly like ExportSubtree but provides the
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// ability to remap method names (e.g. export a lower-case method).
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//
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// The keys in the map are the real method names (exported on the struct), and
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// the values are the method names to be exported on DBus.
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func (conn *Conn) ExportSubtreeWithMap(v interface{}, mapping map[string]string, path ObjectPath, iface string) error {
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return conn.exportWithMap(v, mapping, path, iface, true)
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}
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// exportWithMap is the worker function for all exports/registrations.
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func (conn *Conn) exportWithMap(v interface{}, mapping map[string]string, path ObjectPath, iface string, includeSubtree bool) error {
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if !path.IsValid() {
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return fmt.Errorf(`dbus: Invalid path name: "%s"`, path)
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}
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conn.handlersLck.Lock()
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defer conn.handlersLck.Unlock()
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// Remove a previous export if the interface is nil
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if v == nil {
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if _, ok := conn.handlers[path]; ok {
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delete(conn.handlers[path], iface)
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if len(conn.handlers[path]) == 0 {
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delete(conn.handlers, path)
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}
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}
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return nil
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}
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// If this is the first handler for this path, make a new map to hold all
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// handlers for this path.
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if _, ok := conn.handlers[path]; !ok {
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conn.handlers[path] = make(map[string]exportWithMapping)
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}
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// Finally, save this handler
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conn.handlers[path][iface] = exportWithMapping{export: v, mapping: mapping, includeSubtree: includeSubtree}
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return nil
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}
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// ReleaseName calls org.freedesktop.DBus.ReleaseName and awaits a response.
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func (conn *Conn) ReleaseName(name string) (ReleaseNameReply, error) {
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var r uint32
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err := conn.busObj.Call("org.freedesktop.DBus.ReleaseName", 0, name).Store(&r)
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if err != nil {
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return 0, err
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}
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return ReleaseNameReply(r), nil
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}
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// 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
|
||
|
|
)
|