sshd: support IdentityAgent config

Handle the 'none' value, and change the value to select Pageant to
something that looks like an absolute UNC path name to avoid it's
handled as an relative path name.

Bug: 577053
Change-Id: I4ccf047abbc1def50e2782319e4fa7c744069401
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

org.eclipse.jgit.ssh.apache.agent/src/org/eclipse/jgit/internal/transport/sshd/agent/connector/PageantConnector.java

@@ -26,7 +26,10 @@ public class PageantConnector extends AbstractConnector {
 
 		@Override
 		public String getIdentityAgent() {
-			return "pageant"; //$NON-NLS-1$
+			// This must be an absolute Windows path name to avoid that
+			// OpenSshConfigFile treats it as a relative path name. Use an UNC
+			// name on localhost, like for pipes.
+			return "\\\\.\\pageant"; //$NON-NLS-1$
 		}
 
 		@Override

org.eclipse.jgit.ssh.apache/src/org/eclipse/jgit/internal/transport/sshd/agent/JGitSshAgentFactory.java

@@ -17,11 +17,14 @@
 import org.apache.sshd.agent.SshAgent;
 import org.apache.sshd.agent.SshAgentFactory;
 import org.apache.sshd.agent.SshAgentServer;
+import org.apache.sshd.client.config.hosts.HostConfigEntry;
 import org.apache.sshd.common.FactoryManager;
 import org.apache.sshd.common.channel.ChannelFactory;
 import org.apache.sshd.common.session.ConnectionService;
 import org.apache.sshd.common.session.Session;
 import org.eclipse.jgit.annotations.NonNull;
+import org.eclipse.jgit.internal.transport.sshd.JGitClientSession;
+import org.eclipse.jgit.transport.SshConstants;
 import org.eclipse.jgit.transport.sshd.agent.ConnectorFactory;
 
 /**
@@ -50,19 +53,24 @@ public JGitSshAgentFactory(@NonNull ConnectorFactory factory,
 	@Override
 	public List<ChannelFactory> getChannelForwardingFactories(
 			FactoryManager manager) {
-		// No agent forwarding supported yet.
+		// No agent forwarding supported.
 		return Collections.emptyList();
 	}
 
 	@Override
 	public SshAgent createClient(Session session, FactoryManager manager)
 			throws IOException {
-		// sshd 2.8.0 will pass us the session here. At that point, we can get
-		// the HostConfigEntry and extract and handle the IdentityAgent setting.
-		// For now, pass null to let the ConnectorFactory do its default
-		// behavior (Pageant on Windows, SSH_AUTH_SOCK on Unixes with the
-		// jgit-builtin factory).
-		return new SshAgentClient(factory.create(null, homeDir));
+		String identityAgent = null;
+		if (session instanceof JGitClientSession) {
+			HostConfigEntry hostConfig = ((JGitClientSession) session)
+					.getHostConfigEntry();
+			identityAgent = hostConfig.getProperty(SshConstants.IDENTITY_AGENT,
+					null);
+		}
+		if (SshConstants.NONE.equals(identityAgent)) {
+			return null;
+		}
+		return new SshAgentClient(factory.create(identityAgent, homeDir));
 	}
 
 	@Override

org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/transport/ssh/OpenSshConfigFileTest.java

@@ -562,6 +562,14 @@ public void testEnVarSubstitution() throws Exception {
 				h.getValue(SshConstants.IDENTITY_AGENT));
 	}
 
+	@Test
+	public void testIdentityAgentNone() throws Exception {
+		config("Host orcz\nIdentityAgent none\n");
+		HostConfig h = lookup("orcz");
+		assertEquals(SshConstants.NONE,
+				h.getValue(SshConstants.IDENTITY_AGENT));
+	}
+
 	@Test
 	public void testNegativeMatch() throws Exception {
 		config("Host foo.bar !foobar.baz *.baz\n" + "Port 29418\n");

org.eclipse.jgit/src/org/eclipse/jgit/internal/transport/ssh/OpenSshConfigFile.java

@@ -871,7 +871,7 @@ void substitute(String originalHostName, int port, String userName,
 			if (options != null) {
 				// HOSTNAME already done above
 				String value = options.get(SshConstants.IDENTITY_AGENT);
-				if (value != null) {
+				if (value != null && !SshConstants.NONE.equals(value)) {
 					value = r.substitute(value, Replacer.DEFAULT_TOKENS, true);
 					value = toFile(value, home).getPath();
 					options.put(SshConstants.IDENTITY_AGENT, value);