Class: DBus::Connection

Inherits:
Object
  • Object
show all
Defined in:
lib/dbus/bus.rb

Overview

D-Bus main connection class

Main class that maintains a connection to a bus and can handle incoming and outgoing messages.

Direct Known Subclasses

RemoteBus, SessionBus, SystemBus

Defined Under Namespace

Classes: NameRequestError

Constant Summary collapse

NAME_FLAG_ALLOW_REPLACEMENT =

FIXME: describe the following names, flags and constants. See DBus spec for definition

0x1
NAME_FLAG_REPLACE_EXISTING = 
0x2
NAME_FLAG_DO_NOT_QUEUE = 
0x4
REQUEST_NAME_REPLY_PRIMARY_OWNER = 
0x1
REQUEST_NAME_REPLY_IN_QUEUE = 
0x2
REQUEST_NAME_REPLY_EXISTS = 
0x3
REQUEST_NAME_REPLY_ALREADY_OWNER = 
0x4
DBUSXMLINTRO = 
'<!DOCTYPE node PUBLIC "-//freedesktop//DTD D-BUS Object Introspection 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd">
<node>
  <interface name="org.freedesktop.DBus.Introspectable">
    <method name="Introspect">
      <arg name="data" direction="out" type="s"/>
    </method>
  </interface>
  <interface name="org.freedesktop.DBus">
    <method name="RequestName">
      <arg direction="in" type="s"/>
      <arg direction="in" type="u"/>
      <arg direction="out" type="u"/>
    </method>
    <method name="ReleaseName">
      <arg direction="in" type="s"/>
      <arg direction="out" type="u"/>
    </method>
    <method name="StartServiceByName">
      <arg direction="in" type="s"/>
      <arg direction="in" type="u"/>
      <arg direction="out" type="u"/>
    </method>
    <method name="Hello">
      <arg direction="out" type="s"/>
    </method>
    <method name="NameHasOwner">
      <arg direction="in" type="s"/>
      <arg direction="out" type="b"/>
    </method>
    <method name="ListNames">
      <arg direction="out" type="as"/>
    </method>
    <method name="ListActivatableNames">
      <arg direction="out" type="as"/>
    </method>
    <method name="AddMatch">
      <arg direction="in" type="s"/>
    </method>
    <method name="RemoveMatch">
      <arg direction="in" type="s"/>
    </method>
    <method name="GetNameOwner">
      <arg direction="in" type="s"/>
      <arg direction="out" type="s"/>
    </method>
    <method name="ListQueuedOwners">
      <arg direction="in" type="s"/>
      <arg direction="out" type="as"/>
    </method>
    <method name="GetConnectionUnixUser">
      <arg direction="in" type="s"/>
      <arg direction="out" type="u"/>
    </method>
    <method name="GetConnectionUnixProcessID">
      <arg direction="in" type="s"/>
      <arg direction="out" type="u"/>
    </method>
    <method name="GetConnectionSELinuxSecurityContext">
      <arg direction="in" type="s"/>
      <arg direction="out" type="ay"/>
    </method>
    <method name="ReloadConfig">
    </method>
    <signal name="NameOwnerChanged">
      <arg type="s"/>
      <arg type="s"/>
      <arg type="s"/>
    </signal>
    <signal name="NameLost">
      <arg type="s"/>
    </signal>
    <signal name="NameAcquired">
      <arg type="s"/>
    </signal>
  </interface>
</node>
'
MSG_BUF_SIZE =

The buffer size for messages.

4096

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path) ⇒ Connection

and is something like: “transport1:key1=value1,key2=value2;transport2:key1=value1,key2=value2” e.g. “unix:path=/tmp/dbus-test” or “tcp:host=localhost,port=2687”



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# File 'lib/dbus/bus.rb', line 178

def initialize(path)
  dlog "path: #{path}"
  @path = path
  @unique_name = nil
  @buffer = ""
  @method_call_replies = Hash.new
  @method_call_msgs = Hash.new
  @signal_matchrules = Array.new
  @proxy = nil
  @object_root = Node.new("/")
  @is_tcp = false
end

Instance Attribute Details

#socket ⇒ Object (readonly)

The socket that is used to connect with the bus.



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# File 'lib/dbus/bus.rb', line 170

def socket
  @socket
end

#unique_name ⇒ Object (readonly)

The unique name (by specification) of the message.



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# File 'lib/dbus/bus.rb', line 168

def unique_name
  @unique_name
end

Instance Method Details

#add_match(mr, &slot) ⇒ Object

Asks bus to send us messages matching mr, and execute slot when received



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# File 'lib/dbus/bus.rb', line 551

def add_match(mr, &slot)
  # check this is a signal.
  @signal_matchrules << [mr, slot]
  self.proxy.AddMatch(mr.to_s)
end

#connect ⇒ Object

Connect to the bus and initialize the connection.



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# File 'lib/dbus/bus.rb', line 192

def connect
  connect_to_tcp if @path.include? "tcp:" #connect to tcp socket
  connect_to_unix if @path.include? "unix:" #connect to unix socket
end

#connect_to_tcp ⇒ Object

Connect to a bus over tcp and initialize the connection.



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# File 'lib/dbus/bus.rb', line 198

def connect_to_tcp
  #check if the path is sufficient
  if @path.include? "host=" and @path.include? "port="
    host,port,family = "","",""
    #get the parameters
    @path.split(",").each do |para|
      host = para.sub("tcp:","").sub("host=","") if para.include? "host="
      port = para.sub("port=","").to_i if para.include? "port="
      family = para.sub("family=","") if para.include? "family="
    end
    #dlog "host,port,family : #{host},#{port},#{family}"      
    begin
      #initialize the tcp socket
      @socket = TCPSocket.new(host,port)
      init_connection
      @is_tcp = true
    rescue
      elog "Could not establish connection to: #{@path}, will now exit."
      exit(0) #a little harsh
    end
  else
    #Danger, Will Robinson: the specified "path" is not usable
    elog "supplied path: #{@path}, unusable! sorry."
  end
end

#connect_to_unix ⇒ Object

Connect to an abstract unix bus and initialize the connection.



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# File 'lib/dbus/bus.rb', line 225

def connect_to_unix
  @socket = Socket.new(Socket::Constants::PF_UNIX,Socket::Constants::SOCK_STREAM, 0)
  parse_session_string
  if @transport == "unix" and @type == "abstract"
    if HOST_END == LIL_END
      sockaddr = "\1\0\0#{@unix_abstract}"
    else
      sockaddr = "\0\1\0#{@unix_abstract}"
    end
  elsif @transport == "unix" and @type == "path"
    sockaddr = Socket.pack_sockaddr_un(@unix)
  end
  @socket.connect(sockaddr)
  init_connection
end

#emit(service, obj, intf, sig, *args) ⇒ Object

Emit a signal event for the given service, object obj, interface intf and signal sig with arguments args.



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# File 'lib/dbus/bus.rb', line 619

def emit(service, obj, intf, sig, *args)
  m = Message.new(DBus::Message::SIGNAL)
  m.path = obj.path
  m.interface = intf.name
  m.member = sig.name
  m.sender = service.name
  i = 0
  sig.params.each do |par|
    m.add_param(par[1], args[i])
    i += 1
  end
  send(m.marshall)
end

#glibize ⇒ Object

Tell a bus to register itself on the glib main loop



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# File 'lib/dbus/bus.rb', line 269

def glibize
  require 'glib2'
  # Circumvent a ruby-glib bug
  @channels ||= Array.new

  gio = GLib::IOChannel.new(@socket.fileno)
  @channels << gio
  gio.add_watch(GLib::IOChannel::IN) do |c, ch|
    update_buffer
    messages.each do |msg|
      process(msg)
    end
    true
  end
end

#introspect(dest, path) ⇒ Object

Issues a call to the org.freedesktop.DBus.Introspectable.Introspect method dest is the service and path the object path you want to introspect If a code block is given, the introspect call in asynchronous. If not data is returned

FIXME: link to ProxyObject data definition The returned object is a ProxyObject that has methods you can call to issue somme METHOD_CALL messages, and to setup to receive METHOD_RETURN



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# File 'lib/dbus/bus.rb', line 412

def introspect(dest, path)
  if not block_given?
    # introspect in synchronous !
    data = introspect_data(dest, path)
    pof = DBus::ProxyObjectFactory.new(data, self, dest, path)
    return pof.build
  else
    introspect_data(dest, path) do |data|
      yield(DBus::ProxyObjectFactory.new(data, self, dest, path).build)
    end
  end
end

#introspect_data(dest, path) ⇒ Object 



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# File 'lib/dbus/bus.rb', line 375

def introspect_data(dest, path)
  m = DBus::Message.new(DBus::Message::METHOD_CALL)
  m.path = path
  m.interface = "org.freedesktop.DBus.Introspectable"
  m.destination = dest
  m.member = "Introspect"
  m.sender = unique_name
  if not block_given?
    # introspect in synchronous !
    send_sync(m) do |rmsg|
      if rmsg.is_a?(Error)
        raise rmsg
      else
        return rmsg.params[0]
      end
    end
  else
    send(m.marshall)
    on_return(m) do |rmsg|
      if rmsg.is_a?(Error)
        yield rmsg
      else
        yield rmsg.params[0]
      end
    end
  end
  nil
end

#messages ⇒ Object

Retrieve all the messages that are currently in the buffer.



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# File 'lib/dbus/bus.rb', line 477

def messages
  ret = Array.new
  while msg = pop_message
    ret << msg
  end
  ret
end

#on_return(m, &retc) ⇒ Object

Specify a code block that has to be executed when a reply for message m is received.



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# File 'lib/dbus/bus.rb', line 539

def on_return(m, &retc)
  # Have a better exception here
  if m.message_type != Message::METHOD_CALL
    elog "Funky exception, occured."
    raise "on_return should only get method_calls"
  end
  @method_call_msgs[m.serial] = m
  @method_call_replies[m.serial] = retc
end

#parse_session_string ⇒ Object

Parse the session string (socket address).



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# File 'lib/dbus/bus.rb', line 242

def parse_session_string
  path_parsed = /^([^:]*):([^;]*)$/.match(@path)
  @transport = path_parsed[1]
  adr = path_parsed[2]
  if @transport == "unix"
    adr.split(",").each do |eqstr|
      idx, val = eqstr.split("=")
      case idx
      when "path"
        @type = idx
        @unix = val
      when "abstract"
        @type = idx
        @unix_abstract = val
      when "guid"
        @guid = val
      end
    end
  end
end

#poll_messages ⇒ Object

Update the buffer and retrieve all messages using Connection#messages. Return the messages.



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# File 'lib/dbus/bus.rb', line 490

def poll_messages
  ret = nil
  r, d, d = IO.select([@socket], nil, nil, 0)
  if r and r.size > 0
    update_buffer
  end
  messages
end

#pop_message ⇒ Object

Get one message from the bus and remove it from the buffer. Return the message.



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# File 'lib/dbus/bus.rb', line 465

def pop_message
  ret = nil
  begin
    ret, size = Message.new.unmarshall_buffer(@buffer)
    @buffer.slice!(0, size)
  rescue IncompleteBufferException => e
    # fall through, let ret be null
  end
  ret
end

#process(m) ⇒ Object

Process a message m based on its type.



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# File 'lib/dbus/bus.rb', line 558

def process(m)
  return if m.nil? #check if somethings wrong
  case m.message_type
  when Message::ERROR, Message::METHOD_RETURN
    raise InvalidPacketException if m.reply_serial == nil
    mcs = @method_call_replies[m.reply_serial]
    if not mcs
      dlog "no return code for mcs: #{mcs.inspect} m: #{m.inspect}"
    else
      if m.message_type == Message::ERROR
        mcs.call(Error.new(m))
      else
        mcs.call(m)
      end
      @method_call_replies.delete(m.reply_serial)
      @method_call_msgs.delete(m.reply_serial)
    end
  when DBus::Message::METHOD_CALL
    if m.path == "/org/freedesktop/DBus"
      dlog "Got method call on /org/freedesktop/DBus"
    end
    # handle introspectable as an exception:
    if m.interface == "org.freedesktop.DBus.Introspectable" and
        m.member == "Introspect"
      reply = Message.new(Message::METHOD_RETURN).reply_to(m)
      reply.sender = @unique_name
      node = @service.get_node(m.path)
      raise NotImplementedError if not node
      reply.sender = @unique_name
      reply.add_param(Type::STRING, @service.get_node(m.path).to_xml)
      send(reply.marshall)
    else
      node = @service.get_node(m.path)
      return if node.nil?
      obj = node.object
      return if obj.nil?
      obj.dispatch(m) if obj
    end
  when DBus::Message::SIGNAL
    @signal_matchrules.each do |elem|
      mr, slot = elem
      if mr.match(m)
        slot.call(m)
        return
      end
    end
  else
    dlog "Unknown message type: #{m.message_type}"
  end
end

#proxy ⇒ Object

Set up a ProxyObject for the bus itself, since the bus is introspectable. Returns the object.



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# File 'lib/dbus/bus.rb', line 439

def proxy
  if @proxy == nil
    path = "/org/freedesktop/DBus"
    dest = "org.freedesktop.DBus"
    pof = DBus::ProxyObjectFactory.new(DBUSXMLINTRO, self, dest, path)
    @proxy = pof.build["org.freedesktop.DBus"]
  end
  @proxy
end

#request_service(name) ⇒ Object

Attempt to request a service name.

Raises:



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# File 'lib/dbus/bus.rb', line 430

def request_service(name)
  r = proxy.RequestName(name, NAME_FLAG_REPLACE_EXISTING)
  raise NameRequestError if r[0] != REQUEST_NAME_REPLY_PRIMARY_OWNER
  @service = Service.new(name, self)
  @service
end

#send(buf) ⇒ Object

Send the buffer buf to the bus using Connection#writel.



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# File 'lib/dbus/bus.rb', line 264

def send(buf)
  @socket.write(buf) unless @socket.nil?
end

#send_sync(m, &retc) ⇒ Object

Send a message m on to the bus. This is done synchronously, thus the call will block until a reply message arrives.



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# File 'lib/dbus/bus.rb', line 518

def send_sync(m, &retc) # :yields: reply/return message
  return if m.nil? #check if somethings wrong
  send(m.marshall)
  @method_call_msgs[m.serial] = m
  @method_call_replies[m.serial] = retc

  retm = wait_for_message
  
  return if retm.nil? #check if somethings wrong
  
  process(retm)
  until [DBus::Message::ERROR,
      DBus::Message::METHOD_RETURN].include?(retm.message_type) and
      retm.reply_serial == m.serial
    retm = wait_for_message
    process(retm)
  end
end

#service(name) ⇒ Object Also known as: []

Retrieves the service with the given name.



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# File 'lib/dbus/bus.rb', line 610

def service(name)
  # The service might not exist at this time so we cannot really check
  # anything
  Service.new(name, self)
end

#update_buffer ⇒ Object

Fill (append) the buffer from data that might be available on the socket.



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# File 'lib/dbus/bus.rb', line 451

def update_buffer
  @buffer += @socket.read_nonblock(MSG_BUF_SIZE) if @is_tcp
  unless @is_tcp
    begin
      @buffer += @socket.read_nonblock(MSG_BUF_SIZE)  
    rescue
      wlog ".read_nonblock failed, falling back to .recv"
      @buffer += @socket.recv(MSG_BUF_SIZE)  
    end
  end
end

#wait_for_message ⇒ Object

Wait for a message to arrive. Return it once it is available.



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# File 'lib/dbus/bus.rb', line 500

def wait_for_message
  if @socket.nil?
    elog "Can't wait for messages, @socket is nil."
    return
  end
  ret = pop_message
  while ret == nil
    r, d, d = IO.select([@socket])
    if r and r[0] == @socket
      update_buffer
      ret = pop_message
    end
  end
  ret
end