/*
* Listen on the specified address and port. Return a listener
* that encapsulates the ServerSocket.
*/
ListenKey startListening(String localaddress, int port) throws IOException {
InetSocketAddress sa;
if (localaddress == null) {
sa = new InetSocketAddress(port);
} else {
sa = new InetSocketAddress(localaddress, port);
}
ServerSocket ss = new ServerSocket();
ss.bind(sa);
return new SocketListenKey(ss);
}
/** Stop the listener */
public void stopListening(ListenKey listener) throws IOException {
if (!(listener instanceof SocketListenKey)) {
throw new IllegalArgumentException("Invalid listener");
}
synchronized (listener) {
ServerSocket ss = ((SocketListenKey) listener).socket();
// if the ServerSocket has been closed it means
// the listener is invalid
if (ss.isClosed()) {
throw new IllegalArgumentException("Invalid listener");
}
ss.close();
}
}
/*
* Returns the string representation of the address that this
* listen key represents.
*/
public String address() {
InetAddress address = ss.getInetAddress();
/*
* If bound to the wildcard address then use current local
* hostname. In the event that we don't know our own hostname
* then assume that host supports IPv4 and return something to
* represent the loopback address.
*/
if (address.isAnyLocalAddress()) {
try {
address = InetAddress.getLocalHost();
} catch (UnknownHostException uhe) {
byte[] loopback = {0x7f, 0x00, 0x00, 0x01};
try {
address = InetAddress.getByAddress("127.0.0.1", loopback);
} catch (UnknownHostException x) {
throw new InternalError("unable to get local hostname");
}
}
}
/*
* Now decide if we return a hostname or IP address. Where possible
* return a hostname but in the case that we are bound to an
* address that isn't registered in the name service then we
* return an address.
*/
String result;
String hostname = address.getHostName();
String hostaddr = address.getHostAddress();
if (hostname.equals(hostaddr)) {
if (address instanceof Inet6Address) {
result = "[" + hostaddr + "]";
} else {
result = hostaddr;
}
} else {
result = hostname;
}
/*
* Finally return "hostname:port", "ipv4-address:port" or
* "[ipv6-address]:port".
*/
return result + ":" + ss.getLocalPort();
}
/** Accept a connection from a debuggee and handshake with it. */
public Connection accept(ListenKey listener, long acceptTimeout, long handshakeTimeout)
throws IOException {
if (acceptTimeout < 0 || handshakeTimeout < 0) {
throw new IllegalArgumentException("timeout is negative");
}
if (!(listener instanceof SocketListenKey)) {
throw new IllegalArgumentException("Invalid listener");
}
ServerSocket ss;
// obtain the ServerSocket from the listener - if the
// socket is closed it means the listener is invalid
synchronized (listener) {
ss = ((SocketListenKey) listener).socket();
if (ss.isClosed()) {
throw new IllegalArgumentException("Invalid listener");
}
}
// from here onwards it's possible that the ServerSocket
// may be closed by a call to stopListening - that's okay
// because the ServerSocket methods will throw an
// IOException indicating the socket is closed.
//
// Additionally, it's possible that another thread calls accept
// with a different accept timeout - that creates a same race
// condition between setting the timeout and calling accept.
// As it is such an unlikely scenario (requires both threads
// to be using the same listener we've chosen to ignore the issue).
ss.setSoTimeout((int) acceptTimeout);
Socket s;
try {
s = ss.accept();
} catch (SocketTimeoutException x) {
throw new TransportTimeoutException("timeout waiting for connection");
}
// handshake here
handshake(s, handshakeTimeout);
return new SocketConnection(s);
}