diff options
Diffstat (limited to 'vendor/github.com/godbus/dbus/conn.go')
-rw-r--r-- | vendor/github.com/godbus/dbus/conn.go | 683 |
1 files changed, 683 insertions, 0 deletions
diff --git a/vendor/github.com/godbus/dbus/conn.go b/vendor/github.com/godbus/dbus/conn.go new file mode 100644 index 000000000..5720e2ebb --- /dev/null +++ b/vendor/github.com/godbus/dbus/conn.go @@ -0,0 +1,683 @@ +package dbus + +import ( + "errors" + "io" + "os" + "reflect" + "strings" + "sync" +) + +var ( + systemBus *Conn + systemBusLck sync.Mutex + sessionBus *Conn + sessionBusLck sync.Mutex + sessionEnvLck sync.Mutex +) + +// ErrClosed is the error returned by calls on a closed connection. +var ErrClosed = errors.New("dbus: connection closed by user") + +// Conn represents a connection to a message bus (usually, the system or +// session bus). +// +// Connections are either shared or private. Shared connections +// are shared between calls to the functions that return them. As a result, +// the methods Close, Auth and Hello must not be called on them. +// +// Multiple goroutines may invoke methods on a connection simultaneously. +type Conn struct { + transport + + busObj BusObject + unixFD bool + uuid string + + names []string + namesLck sync.RWMutex + + serialLck sync.Mutex + nextSerial uint32 + serialUsed map[uint32]bool + + calls map[uint32]*Call + callsLck sync.RWMutex + + handler Handler + + out chan *Message + closed bool + outLck sync.RWMutex + + signalHandler SignalHandler + + eavesdropped chan<- *Message + eavesdroppedLck sync.Mutex +} + +// SessionBus returns a shared connection to the session bus, connecting to it +// if not already done. +func SessionBus() (conn *Conn, err error) { + sessionBusLck.Lock() + defer sessionBusLck.Unlock() + if sessionBus != nil { + return sessionBus, nil + } + defer func() { + if conn != nil { + sessionBus = conn + } + }() + conn, err = SessionBusPrivate() + if err != nil { + return + } + if err = conn.Auth(nil); err != nil { + conn.Close() + conn = nil + return + } + if err = conn.Hello(); err != nil { + conn.Close() + conn = nil + } + return +} + +func getSessionBusAddress() (string, error) { + sessionEnvLck.Lock() + defer sessionEnvLck.Unlock() + address := os.Getenv("DBUS_SESSION_BUS_ADDRESS") + if address != "" && address != "autolaunch:" { + return address, nil + } + return getSessionBusPlatformAddress() +} + +// SessionBusPrivate returns a new private connection to the session bus. +func SessionBusPrivate() (*Conn, error) { + address, err := getSessionBusAddress() + if err != nil { + return nil, err + } + + return Dial(address) +} + +// SessionBusPrivate returns a new private connection to the session bus. +func SessionBusPrivateHandler(handler Handler, signalHandler SignalHandler) (*Conn, error) { + address, err := getSessionBusAddress() + if err != nil { + return nil, err + } + return DialHandler(address, handler, signalHandler) +} + +// SystemBus returns a shared connection to the system bus, connecting to it if +// not already done. +func SystemBus() (conn *Conn, err error) { + systemBusLck.Lock() + defer systemBusLck.Unlock() + if systemBus != nil { + return systemBus, nil + } + defer func() { + if conn != nil { + systemBus = conn + } + }() + conn, err = SystemBusPrivate() + if err != nil { + return + } + if err = conn.Auth(nil); err != nil { + conn.Close() + conn = nil + return + } + if err = conn.Hello(); err != nil { + conn.Close() + conn = nil + } + return +} + +// SystemBusPrivate returns a new private connection to the system bus. +func SystemBusPrivate() (*Conn, error) { + return Dial(getSystemBusPlatformAddress()) +} + +// SystemBusPrivateHandler returns a new private connection to the system bus, using the provided handlers. +func SystemBusPrivateHandler(handler Handler, signalHandler SignalHandler) (*Conn, error) { + return DialHandler(getSystemBusPlatformAddress(), handler, signalHandler) +} + +// Dial establishes a new private connection to the message bus specified by address. +func Dial(address string) (*Conn, error) { + tr, err := getTransport(address) + if err != nil { + return nil, err + } + return newConn(tr, NewDefaultHandler(), NewDefaultSignalHandler()) +} + +// DialHandler establishes a new private connection to the message bus specified by address, using the supplied handlers. +func DialHandler(address string, handler Handler, signalHandler SignalHandler) (*Conn, error) { + tr, err := getTransport(address) + if err != nil { + return nil, err + } + return newConn(tr, handler, signalHandler) +} + +// NewConn creates a new private *Conn from an already established connection. +func NewConn(conn io.ReadWriteCloser) (*Conn, error) { + return NewConnHandler(conn, NewDefaultHandler(), NewDefaultSignalHandler()) +} + +// NewConnHandler creates a new private *Conn from an already established connection, using the supplied handlers. +func NewConnHandler(conn io.ReadWriteCloser, handler Handler, signalHandler SignalHandler) (*Conn, error) { + return newConn(genericTransport{conn}, handler, signalHandler) +} + +// newConn creates a new *Conn from a transport. +func newConn(tr transport, handler Handler, signalHandler SignalHandler) (*Conn, error) { + conn := new(Conn) + conn.transport = tr + conn.calls = make(map[uint32]*Call) + conn.out = make(chan *Message, 10) + conn.handler = handler + conn.signalHandler = signalHandler + conn.nextSerial = 1 + conn.serialUsed = map[uint32]bool{0: true} + conn.busObj = conn.Object("org.freedesktop.DBus", "/org/freedesktop/DBus") + return conn, nil +} + +// BusObject returns the object owned by the bus daemon which handles +// administrative requests. +func (conn *Conn) BusObject() BusObject { + return conn.busObj +} + +// Close closes the connection. Any blocked operations will return with errors +// and the channels passed to Eavesdrop and Signal are closed. This method must +// not be called on shared connections. +func (conn *Conn) Close() error { + conn.outLck.Lock() + if conn.closed { + // inWorker calls Close on read error, the read error may + // be caused by another caller calling Close to shutdown the + // dbus connection, a double-close scenario we prevent here. + conn.outLck.Unlock() + return nil + } + close(conn.out) + conn.closed = true + conn.outLck.Unlock() + + if term, ok := conn.signalHandler.(Terminator); ok { + term.Terminate() + } + + if term, ok := conn.handler.(Terminator); ok { + term.Terminate() + } + + conn.eavesdroppedLck.Lock() + if conn.eavesdropped != nil { + close(conn.eavesdropped) + } + conn.eavesdroppedLck.Unlock() + + return conn.transport.Close() +} + +// Eavesdrop causes conn to send all incoming messages to the given channel +// without further processing. Method replies, errors and signals will not be +// sent to the appropiate channels and method calls will not be handled. If nil +// is passed, the normal behaviour is restored. +// +// The caller has to make sure that ch is sufficiently buffered; +// if a message arrives when a write to ch is not possible, the message is +// discarded. +func (conn *Conn) Eavesdrop(ch chan<- *Message) { + conn.eavesdroppedLck.Lock() + conn.eavesdropped = ch + conn.eavesdroppedLck.Unlock() +} + +// getSerial returns an unused serial. +func (conn *Conn) getSerial() uint32 { + conn.serialLck.Lock() + defer conn.serialLck.Unlock() + n := conn.nextSerial + for conn.serialUsed[n] { + n++ + } + conn.serialUsed[n] = true + conn.nextSerial = n + 1 + return n +} + +// Hello sends the initial org.freedesktop.DBus.Hello call. This method must be +// called after authentication, but before sending any other messages to the +// bus. Hello must not be called for shared connections. +func (conn *Conn) Hello() error { + var s string + err := conn.busObj.Call("org.freedesktop.DBus.Hello", 0).Store(&s) + if err != nil { + return err + } + conn.namesLck.Lock() + conn.names = make([]string, 1) + conn.names[0] = s + conn.namesLck.Unlock() + return nil +} + +// inWorker runs in an own goroutine, reading incoming messages from the +// transport and dispatching them appropiately. +func (conn *Conn) inWorker() { + for { + msg, err := conn.ReadMessage() + if err == nil { + conn.eavesdroppedLck.Lock() + if conn.eavesdropped != nil { + select { + case conn.eavesdropped <- msg: + default: + } + conn.eavesdroppedLck.Unlock() + continue + } + conn.eavesdroppedLck.Unlock() + dest, _ := msg.Headers[FieldDestination].value.(string) + found := false + if dest == "" { + found = true + } else { + conn.namesLck.RLock() + if len(conn.names) == 0 { + found = true + } + for _, v := range conn.names { + if dest == v { + found = true + break + } + } + conn.namesLck.RUnlock() + } + if !found { + // Eavesdropped a message, but no channel for it is registered. + // Ignore it. + continue + } + switch msg.Type { + case TypeMethodReply, TypeError: + serial := msg.Headers[FieldReplySerial].value.(uint32) + conn.callsLck.Lock() + if c, ok := conn.calls[serial]; ok { + if msg.Type == TypeError { + name, _ := msg.Headers[FieldErrorName].value.(string) + c.Err = Error{name, msg.Body} + } else { + c.Body = msg.Body + } + c.Done <- c + conn.serialLck.Lock() + delete(conn.serialUsed, serial) + conn.serialLck.Unlock() + delete(conn.calls, serial) + } + conn.callsLck.Unlock() + case TypeSignal: + iface := msg.Headers[FieldInterface].value.(string) + member := msg.Headers[FieldMember].value.(string) + // as per http://dbus.freedesktop.org/doc/dbus-specification.html , + // sender is optional for signals. + sender, _ := msg.Headers[FieldSender].value.(string) + if iface == "org.freedesktop.DBus" && sender == "org.freedesktop.DBus" { + if member == "NameLost" { + // If we lost the name on the bus, remove it from our + // tracking list. + name, ok := msg.Body[0].(string) + if !ok { + panic("Unable to read the lost name") + } + conn.namesLck.Lock() + for i, v := range conn.names { + if v == name { + conn.names = append(conn.names[:i], + conn.names[i+1:]...) + } + } + conn.namesLck.Unlock() + } else if member == "NameAcquired" { + // If we acquired the name on the bus, add it to our + // tracking list. + name, ok := msg.Body[0].(string) + if !ok { + panic("Unable to read the acquired name") + } + conn.namesLck.Lock() + conn.names = append(conn.names, name) + conn.namesLck.Unlock() + } + } + conn.handleSignal(msg) + case TypeMethodCall: + go conn.handleCall(msg) + } + } else if _, ok := err.(InvalidMessageError); !ok { + // Some read error occured (usually EOF); we can't really do + // anything but to shut down all stuff and returns errors to all + // pending replies. + conn.Close() + conn.callsLck.RLock() + for _, v := range conn.calls { + v.Err = err + v.Done <- v + } + conn.callsLck.RUnlock() + return + } + // invalid messages are ignored + } +} + +func (conn *Conn) handleSignal(msg *Message) { + iface := msg.Headers[FieldInterface].value.(string) + member := msg.Headers[FieldMember].value.(string) + // as per http://dbus.freedesktop.org/doc/dbus-specification.html , + // sender is optional for signals. + sender, _ := msg.Headers[FieldSender].value.(string) + signal := &Signal{ + Sender: sender, + Path: msg.Headers[FieldPath].value.(ObjectPath), + Name: iface + "." + member, + Body: msg.Body, + } + conn.signalHandler.DeliverSignal(iface, member, signal) +} + +// Names returns the list of all names that are currently owned by this +// connection. The slice is always at least one element long, the first element +// being the unique name of the connection. +func (conn *Conn) Names() []string { + conn.namesLck.RLock() + // copy the slice so it can't be modified + s := make([]string, len(conn.names)) + copy(s, conn.names) + conn.namesLck.RUnlock() + return s +} + +// Object returns the object identified by the given destination name and path. +func (conn *Conn) Object(dest string, path ObjectPath) BusObject { + return &Object{conn, dest, path} +} + +// outWorker runs in an own goroutine, encoding and sending messages that are +// sent to conn.out. +func (conn *Conn) outWorker() { + for msg := range conn.out { + err := conn.SendMessage(msg) + conn.callsLck.RLock() + if err != nil { + if c := conn.calls[msg.serial]; c != nil { + c.Err = err + c.Done <- c + } + conn.serialLck.Lock() + delete(conn.serialUsed, msg.serial) + conn.serialLck.Unlock() + } else if msg.Type != TypeMethodCall { + conn.serialLck.Lock() + delete(conn.serialUsed, msg.serial) + conn.serialLck.Unlock() + } + conn.callsLck.RUnlock() + } +} + +// Send sends the given message to the message bus. You usually don't need to +// use this; use the higher-level equivalents (Call / Go, Emit and Export) +// instead. If msg is a method call and NoReplyExpected is not set, a non-nil +// call is returned and the same value is sent to ch (which must be buffered) +// once the call is complete. Otherwise, ch is ignored and a Call structure is +// returned of which only the Err member is valid. +func (conn *Conn) Send(msg *Message, ch chan *Call) *Call { + var call *Call + + msg.serial = conn.getSerial() + if msg.Type == TypeMethodCall && msg.Flags&FlagNoReplyExpected == 0 { + if ch == nil { + ch = make(chan *Call, 5) + } else if cap(ch) == 0 { + panic("dbus: unbuffered channel passed to (*Conn).Send") + } + call = new(Call) + call.Destination, _ = msg.Headers[FieldDestination].value.(string) + call.Path, _ = msg.Headers[FieldPath].value.(ObjectPath) + iface, _ := msg.Headers[FieldInterface].value.(string) + member, _ := msg.Headers[FieldMember].value.(string) + call.Method = iface + "." + member + call.Args = msg.Body + call.Done = ch + conn.callsLck.Lock() + conn.calls[msg.serial] = call + conn.callsLck.Unlock() + conn.outLck.RLock() + if conn.closed { + call.Err = ErrClosed + call.Done <- call + } else { + conn.out <- msg + } + conn.outLck.RUnlock() + } else { + conn.outLck.RLock() + if conn.closed { + call = &Call{Err: ErrClosed} + } else { + conn.out <- msg + call = &Call{Err: nil} + } + conn.outLck.RUnlock() + } + return call +} + +// sendError creates an error message corresponding to the parameters and sends +// it to conn.out. +func (conn *Conn) sendError(err error, dest string, serial uint32) { + var e *Error + switch em := err.(type) { + case Error: + e = &em + case *Error: + e = em + case DBusError: + name, body := em.DBusError() + e = NewError(name, body) + default: + e = MakeFailedError(err) + } + msg := new(Message) + msg.Type = TypeError + msg.serial = conn.getSerial() + msg.Headers = make(map[HeaderField]Variant) + if dest != "" { + msg.Headers[FieldDestination] = MakeVariant(dest) + } + msg.Headers[FieldErrorName] = MakeVariant(e.Name) + msg.Headers[FieldReplySerial] = MakeVariant(serial) + msg.Body = e.Body + if len(e.Body) > 0 { + msg.Headers[FieldSignature] = MakeVariant(SignatureOf(e.Body...)) + } + conn.outLck.RLock() + if !conn.closed { + conn.out <- msg + } + conn.outLck.RUnlock() +} + +// sendReply creates a method reply message corresponding to the parameters and +// sends it to conn.out. +func (conn *Conn) sendReply(dest string, serial uint32, values ...interface{}) { + msg := new(Message) + msg.Type = TypeMethodReply + msg.serial = conn.getSerial() + msg.Headers = make(map[HeaderField]Variant) + if dest != "" { + msg.Headers[FieldDestination] = MakeVariant(dest) + } + msg.Headers[FieldReplySerial] = MakeVariant(serial) + msg.Body = values + if len(values) > 0 { + msg.Headers[FieldSignature] = MakeVariant(SignatureOf(values...)) + } + conn.outLck.RLock() + if !conn.closed { + conn.out <- msg + } + conn.outLck.RUnlock() +} + +func (conn *Conn) defaultSignalAction(fn func(h *defaultSignalHandler, ch chan<- *Signal), ch chan<- *Signal) { + if !isDefaultSignalHandler(conn.signalHandler) { + return + } + handler := conn.signalHandler.(*defaultSignalHandler) + fn(handler, ch) +} + +// Signal registers the given channel to be passed all received signal messages. +// The caller has to make sure that ch is sufficiently buffered; if a message +// arrives when a write to c is not possible, it is discarded. +// +// Multiple of these channels can be registered at the same time. +// +// These channels are "overwritten" by Eavesdrop; i.e., if there currently is a +// channel for eavesdropped messages, this channel receives all signals, and +// none of the channels passed to Signal will receive any signals. +func (conn *Conn) Signal(ch chan<- *Signal) { + conn.defaultSignalAction((*defaultSignalHandler).addSignal, ch) +} + +// RemoveSignal removes the given channel from the list of the registered channels. +func (conn *Conn) RemoveSignal(ch chan<- *Signal) { + conn.defaultSignalAction((*defaultSignalHandler).removeSignal, ch) +} + +// SupportsUnixFDs returns whether the underlying transport supports passing of +// unix file descriptors. If this is false, method calls containing unix file +// descriptors will return an error and emitted signals containing them will +// not be sent. +func (conn *Conn) SupportsUnixFDs() bool { + return conn.unixFD +} + +// Error represents a D-Bus message of type Error. +type Error struct { + Name string + Body []interface{} +} + +func NewError(name string, body []interface{}) *Error { + return &Error{name, body} +} + +func (e Error) Error() string { + if len(e.Body) >= 1 { + s, ok := e.Body[0].(string) + if ok { + return s + } + } + return e.Name +} + +// Signal represents a D-Bus message of type Signal. The name member is given in +// "interface.member" notation, e.g. org.freedesktop.D-Bus.NameLost. +type Signal struct { + Sender string + Path ObjectPath + Name string + Body []interface{} +} + +// transport is a D-Bus transport. +type transport interface { + // Read and Write raw data (for example, for the authentication protocol). + io.ReadWriteCloser + + // Send the initial null byte used for the EXTERNAL mechanism. + SendNullByte() error + + // Returns whether this transport supports passing Unix FDs. + SupportsUnixFDs() bool + + // Signal the transport that Unix FD passing is enabled for this connection. + EnableUnixFDs() + + // Read / send a message, handling things like Unix FDs. + ReadMessage() (*Message, error) + SendMessage(*Message) error +} + +var ( + transports = make(map[string]func(string) (transport, error)) +) + +func getTransport(address string) (transport, error) { + var err error + var t transport + + addresses := strings.Split(address, ";") + for _, v := range addresses { + i := strings.IndexRune(v, ':') + if i == -1 { + err = errors.New("dbus: invalid bus address (no transport)") + continue + } + f := transports[v[:i]] + if f == nil { + err = errors.New("dbus: invalid bus address (invalid or unsupported transport)") + continue + } + t, err = f(v[i+1:]) + if err == nil { + return t, nil + } + } + return nil, err +} + +// dereferenceAll returns a slice that, assuming that vs is a slice of pointers +// of arbitrary types, containes the values that are obtained from dereferencing +// all elements in vs. +func dereferenceAll(vs []interface{}) []interface{} { + for i := range vs { + v := reflect.ValueOf(vs[i]) + v = v.Elem() + vs[i] = v.Interface() + } + return vs +} + +// getKey gets a key from a the list of keys. Returns "" on error / not found... +func getKey(s, key string) string { + for _, keyEqualsValue := range strings.Split(s, ",") { + keyValue := strings.SplitN(keyEqualsValue, "=", 2) + if len(keyValue) == 2 && keyValue[0] == key { + return keyValue[1] + } + } + return "" +} |