diff options
Diffstat (limited to 'vendor/github.com/godbus/dbus/message.go')
-rw-r--r-- | vendor/github.com/godbus/dbus/message.go | 353 |
1 files changed, 353 insertions, 0 deletions
diff --git a/vendor/github.com/godbus/dbus/message.go b/vendor/github.com/godbus/dbus/message.go new file mode 100644 index 000000000..6a925367e --- /dev/null +++ b/vendor/github.com/godbus/dbus/message.go @@ -0,0 +1,353 @@ +package dbus + +import ( + "bytes" + "encoding/binary" + "errors" + "io" + "reflect" + "strconv" +) + +const protoVersion byte = 1 + +// Flags represents the possible flags of a D-Bus message. +type Flags byte + +const ( + // FlagNoReplyExpected signals that the message is not expected to generate + // a reply. If this flag is set on outgoing messages, any possible reply + // will be discarded. + FlagNoReplyExpected Flags = 1 << iota + // FlagNoAutoStart signals that the message bus should not automatically + // start an application when handling this message. + FlagNoAutoStart + // FlagAllowInteractiveAuthorization may be set on a method call + // message to inform the receiving side that the caller is prepared + // to wait for interactive authorization, which might take a + // considerable time to complete. For instance, if this flag is set, + // it would be appropriate to query the user for passwords or + // confirmation via Polkit or a similar framework. + FlagAllowInteractiveAuthorization +) + +// Type represents the possible types of a D-Bus message. +type Type byte + +const ( + TypeMethodCall Type = 1 + iota + TypeMethodReply + TypeError + TypeSignal + typeMax +) + +func (t Type) String() string { + switch t { + case TypeMethodCall: + return "method call" + case TypeMethodReply: + return "reply" + case TypeError: + return "error" + case TypeSignal: + return "signal" + } + return "invalid" +} + +// HeaderField represents the possible byte codes for the headers +// of a D-Bus message. +type HeaderField byte + +const ( + FieldPath HeaderField = 1 + iota + FieldInterface + FieldMember + FieldErrorName + FieldReplySerial + FieldDestination + FieldSender + FieldSignature + FieldUnixFDs + fieldMax +) + +// An InvalidMessageError describes the reason why a D-Bus message is regarded as +// invalid. +type InvalidMessageError string + +func (e InvalidMessageError) Error() string { + return "dbus: invalid message: " + string(e) +} + +// fieldType are the types of the various header fields. +var fieldTypes = [fieldMax]reflect.Type{ + FieldPath: objectPathType, + FieldInterface: stringType, + FieldMember: stringType, + FieldErrorName: stringType, + FieldReplySerial: uint32Type, + FieldDestination: stringType, + FieldSender: stringType, + FieldSignature: signatureType, + FieldUnixFDs: uint32Type, +} + +// requiredFields lists the header fields that are required by the different +// message types. +var requiredFields = [typeMax][]HeaderField{ + TypeMethodCall: {FieldPath, FieldMember}, + TypeMethodReply: {FieldReplySerial}, + TypeError: {FieldErrorName, FieldReplySerial}, + TypeSignal: {FieldPath, FieldInterface, FieldMember}, +} + +// Message represents a single D-Bus message. +type Message struct { + Type + Flags + Headers map[HeaderField]Variant + Body []interface{} + + serial uint32 +} + +type header struct { + Field byte + Variant +} + +// DecodeMessage tries to decode a single message in the D-Bus wire format +// from the given reader. The byte order is figured out from the first byte. +// The possibly returned error can be an error of the underlying reader, an +// InvalidMessageError or a FormatError. +func DecodeMessage(rd io.Reader) (msg *Message, err error) { + var order binary.ByteOrder + var hlength, length uint32 + var typ, flags, proto byte + var headers []header + + b := make([]byte, 1) + _, err = rd.Read(b) + if err != nil { + return + } + switch b[0] { + case 'l': + order = binary.LittleEndian + case 'B': + order = binary.BigEndian + default: + return nil, InvalidMessageError("invalid byte order") + } + + dec := newDecoder(rd, order) + dec.pos = 1 + + msg = new(Message) + vs, err := dec.Decode(Signature{"yyyuu"}) + if err != nil { + return nil, err + } + if err = Store(vs, &typ, &flags, &proto, &length, &msg.serial); err != nil { + return nil, err + } + msg.Type = Type(typ) + msg.Flags = Flags(flags) + + // get the header length separately because we need it later + b = make([]byte, 4) + _, err = io.ReadFull(rd, b) + if err != nil { + return nil, err + } + binary.Read(bytes.NewBuffer(b), order, &hlength) + if hlength+length+16 > 1<<27 { + return nil, InvalidMessageError("message is too long") + } + dec = newDecoder(io.MultiReader(bytes.NewBuffer(b), rd), order) + dec.pos = 12 + vs, err = dec.Decode(Signature{"a(yv)"}) + if err != nil { + return nil, err + } + if err = Store(vs, &headers); err != nil { + return nil, err + } + + msg.Headers = make(map[HeaderField]Variant) + for _, v := range headers { + msg.Headers[HeaderField(v.Field)] = v.Variant + } + + dec.align(8) + body := make([]byte, int(length)) + if length != 0 { + _, err := io.ReadFull(rd, body) + if err != nil { + return nil, err + } + } + + if err = msg.IsValid(); err != nil { + return nil, err + } + sig, _ := msg.Headers[FieldSignature].value.(Signature) + if sig.str != "" { + buf := bytes.NewBuffer(body) + dec = newDecoder(buf, order) + vs, err := dec.Decode(sig) + if err != nil { + return nil, err + } + msg.Body = vs + } + + return +} + +// EncodeTo encodes and sends a message to the given writer. The byte order must +// be either binary.LittleEndian or binary.BigEndian. If the message is not +// valid or an error occurs when writing, an error is returned. +func (msg *Message) EncodeTo(out io.Writer, order binary.ByteOrder) error { + if err := msg.IsValid(); err != nil { + return err + } + var vs [7]interface{} + switch order { + case binary.LittleEndian: + vs[0] = byte('l') + case binary.BigEndian: + vs[0] = byte('B') + default: + return errors.New("dbus: invalid byte order") + } + body := new(bytes.Buffer) + enc := newEncoder(body, order) + if len(msg.Body) != 0 { + enc.Encode(msg.Body...) + } + vs[1] = msg.Type + vs[2] = msg.Flags + vs[3] = protoVersion + vs[4] = uint32(len(body.Bytes())) + vs[5] = msg.serial + headers := make([]header, 0, len(msg.Headers)) + for k, v := range msg.Headers { + headers = append(headers, header{byte(k), v}) + } + vs[6] = headers + var buf bytes.Buffer + enc = newEncoder(&buf, order) + enc.Encode(vs[:]...) + enc.align(8) + body.WriteTo(&buf) + if buf.Len() > 1<<27 { + return InvalidMessageError("message is too long") + } + if _, err := buf.WriteTo(out); err != nil { + return err + } + return nil +} + +// IsValid checks whether msg is a valid message and returns an +// InvalidMessageError if it is not. +func (msg *Message) IsValid() error { + if msg.Flags & ^(FlagNoAutoStart|FlagNoReplyExpected|FlagAllowInteractiveAuthorization) != 0 { + return InvalidMessageError("invalid flags") + } + if msg.Type == 0 || msg.Type >= typeMax { + return InvalidMessageError("invalid message type") + } + for k, v := range msg.Headers { + if k == 0 || k >= fieldMax { + return InvalidMessageError("invalid header") + } + if reflect.TypeOf(v.value) != fieldTypes[k] { + return InvalidMessageError("invalid type of header field") + } + } + for _, v := range requiredFields[msg.Type] { + if _, ok := msg.Headers[v]; !ok { + return InvalidMessageError("missing required header") + } + } + if path, ok := msg.Headers[FieldPath]; ok { + if !path.value.(ObjectPath).IsValid() { + return InvalidMessageError("invalid path name") + } + } + if iface, ok := msg.Headers[FieldInterface]; ok { + if !isValidInterface(iface.value.(string)) { + return InvalidMessageError("invalid interface name") + } + } + if member, ok := msg.Headers[FieldMember]; ok { + if !isValidMember(member.value.(string)) { + return InvalidMessageError("invalid member name") + } + } + if errname, ok := msg.Headers[FieldErrorName]; ok { + if !isValidInterface(errname.value.(string)) { + return InvalidMessageError("invalid error name") + } + } + if len(msg.Body) != 0 { + if _, ok := msg.Headers[FieldSignature]; !ok { + return InvalidMessageError("missing signature") + } + } + return nil +} + +// Serial returns the message's serial number. The returned value is only valid +// for messages received by eavesdropping. +func (msg *Message) Serial() uint32 { + return msg.serial +} + +// String returns a string representation of a message similar to the format of +// dbus-monitor. +func (msg *Message) String() string { + if err := msg.IsValid(); err != nil { + return "<invalid>" + } + s := msg.Type.String() + if v, ok := msg.Headers[FieldSender]; ok { + s += " from " + v.value.(string) + } + if v, ok := msg.Headers[FieldDestination]; ok { + s += " to " + v.value.(string) + } + s += " serial " + strconv.FormatUint(uint64(msg.serial), 10) + if v, ok := msg.Headers[FieldReplySerial]; ok { + s += " reply_serial " + strconv.FormatUint(uint64(v.value.(uint32)), 10) + } + if v, ok := msg.Headers[FieldUnixFDs]; ok { + s += " unixfds " + strconv.FormatUint(uint64(v.value.(uint32)), 10) + } + if v, ok := msg.Headers[FieldPath]; ok { + s += " path " + string(v.value.(ObjectPath)) + } + if v, ok := msg.Headers[FieldInterface]; ok { + s += " interface " + v.value.(string) + } + if v, ok := msg.Headers[FieldErrorName]; ok { + s += " error " + v.value.(string) + } + if v, ok := msg.Headers[FieldMember]; ok { + s += " member " + v.value.(string) + } + if len(msg.Body) != 0 { + s += "\n" + } + for i, v := range msg.Body { + s += " " + MakeVariant(v).String() + if i != len(msg.Body)-1 { + s += "\n" + } + } + return s +} |