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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
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package jdk.internal.agent;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.lang.management.ManagementFactory;
import java.lang.reflect.Method;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.UnknownHostException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.Properties;
import java.util.ResourceBundle;
import java.util.ServiceLoader;
import java.util.function.Function;
import java.util.function.Predicate;

import javax.management.remote.JMXConnectorServer;
import javax.management.remote.JMXServiceURL;

import static jdk.internal.agent.AgentConfigurationError.*;
import jdk.internal.agent.spi.AgentProvider;
import jdk.internal.vm.VMSupport;
import sun.management.jdp.JdpController;
import sun.management.jdp.JdpException;
import sun.management.jmxremote.ConnectorBootstrap;

This class provides the methods to start the management agent. 1. startAgent method is invoked by the VM if -Dcom.sun.management.* is set 2. startLocalManagementAgent or startRemoteManagementAgent is invoked to start the management agent after the VM starts via jcmd ManagementAgent.start and start_local command.
/** * This class provides the methods to start the management agent. * 1. {@link #startAgent} method is invoked by the VM if {@code -Dcom.sun.management.*} is set * 2. {@link #startLocalManagementAgent} or {@link #startRemoteManagementAgent} * is invoked to start the management agent after the VM starts * via jcmd ManagementAgent.start and start_local command. */
public class Agent {
Agent status collector strategy class
/** * Agent status collector strategy class */
private static abstract class StatusCollector { protected static final Map<String, String> DEFAULT_PROPS = new HashMap<>(); static { DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.PORT, ConnectorBootstrap.DefaultValues.PORT); DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.USE_LOCAL_ONLY, ConnectorBootstrap.DefaultValues.USE_LOCAL_ONLY); DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.USE_AUTHENTICATION, ConnectorBootstrap.DefaultValues.USE_AUTHENTICATION); DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.USE_SSL, ConnectorBootstrap.DefaultValues.USE_SSL); DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.USE_REGISTRY_SSL, ConnectorBootstrap.DefaultValues.USE_REGISTRY_SSL); DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.SSL_NEED_CLIENT_AUTH, ConnectorBootstrap.DefaultValues.SSL_NEED_CLIENT_AUTH); DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.CONFIG_FILE_NAME, ConnectorBootstrap.DefaultValues.CONFIG_FILE_NAME); DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.PASSWORD_FILE_NAME, ConnectorBootstrap.DefaultValues.PASSWORD_FILE_NAME); DEFAULT_PROPS.put(ConnectorBootstrap.PropertyNames.ACCESS_FILE_NAME, ConnectorBootstrap.DefaultValues.ACCESS_FILE_NAME); } final protected StringBuilder sb = new StringBuilder(); final public String collect() { Properties agentProps = VMSupport.getAgentProperties(); String localConnAddr = (String)agentProps.get(LOCAL_CONNECTOR_ADDRESS_PROP); if (localConnAddr != null || jmxServer != null) { addAgentStatus(true); appendConnections(localConnAddr); } else { addAgentStatus(false); } return sb.toString(); } private void appendConnections(String localConnAddr) { appendConnectionsHeader(); if (localConnAddr != null) { try { JMXServiceURL u = new JMXServiceURL(localConnAddr); addConnection(false, u); } catch (MalformedURLException e) { // will never happen } } if (jmxServer != null) { addConnection(true, jmxServer.getAddress()); } appendConnectionsFooter(); } private void addConnection(boolean remote, JMXServiceURL u) { appendConnectionHeader(remote); addConnectionDetails(u); addConfigProperties(); appendConnectionFooter(remote); } private void addConfigProperties() { appendConfigPropsHeader(); Properties remoteProps = configProps != null ? configProps : getManagementProperties(); Map<Object, Object> props = new HashMap<>(DEFAULT_PROPS); if (remoteProps == null) { // local connector only String loc_only = System.getProperty( ConnectorBootstrap.PropertyNames.USE_LOCAL_ONLY ); if (loc_only != null && !ConnectorBootstrap.DefaultValues.USE_LOCAL_ONLY.equals(loc_only)) { props.put( ConnectorBootstrap.PropertyNames.USE_LOCAL_ONLY, loc_only ); } } else { props.putAll(remoteProps); } props.entrySet().stream() .filter(preprocess(Map.Entry::getKey, StatusCollector::isManagementProp)) .forEach(this::addConfigProp); appendConfigPropsFooter(); } private static boolean isManagementProp(Object pName) { return pName != null && pName.toString().startsWith("com.sun.management."); } private static <T, V> Predicate<T> preprocess(Function<T, V> f, Predicate<V> p) { return (T t) -> p.test(f.apply(t)); } abstract protected void addAgentStatus(boolean enabled); abstract protected void appendConnectionsHeader(); abstract protected void appendConnectionsFooter(); abstract protected void addConnectionDetails(JMXServiceURL u); abstract protected void appendConnectionHeader(boolean remote); abstract protected void appendConnectionFooter(boolean remote); abstract protected void appendConfigPropsHeader(); abstract protected void appendConfigPropsFooter(); abstract protected void addConfigProp(Map.Entry<?, ?> prop); }
Free-text status collector strategy implementation
/** * Free-text status collector strategy implementation */
final private static class TextStatusCollector extends StatusCollector { @Override protected void addAgentStatus(boolean enabled) { sb.append("Agent: ").append(enabled ? "enabled" : "disabled").append('\n'); } @Override protected void appendConnectionsHeader() { sb.append('\n'); } @Override protected void addConnectionDetails(JMXServiceURL u) { sb.append("Protocol : ").append(u.getProtocol()).append('\n') .append("Host : ").append(u.getHost()).append('\n') .append("URL : ").append(u).append('\n'); } @Override protected void appendConnectionHeader(boolean remote) { sb.append("Connection Type: ").append(remote ? "remote" : "local").append('\n'); } @Override protected void appendConfigPropsHeader() { sb.append("Properties :\n"); } @Override protected void addConfigProp(Map.Entry<?, ?> prop) { sb.append(" ").append(prop.getKey()).append(" = ") .append(prop.getValue()); Object defVal = DEFAULT_PROPS.get(prop.getKey()); if (defVal != null && defVal.equals(prop.getValue())) { sb.append(" [default]"); } sb.append("\n"); } @Override protected void appendConnectionsFooter() {} @Override protected void appendConnectionFooter(boolean remote) { sb.append('\n'); } @Override protected void appendConfigPropsFooter() {} } // management properties private static Properties mgmtProps; private static ResourceBundle messageRB; private static final String CONFIG_FILE = "com.sun.management.config.file"; private static final String JMXREMOTE = "com.sun.management.jmxremote"; private static final String JMXREMOTE_PORT = "com.sun.management.jmxremote.port"; private static final String RMI_PORT = "com.sun.management.jmxremote.rmi.port"; private static final String ENABLE_THREAD_CONTENTION_MONITORING = "com.sun.management.enableThreadContentionMonitoring"; private static final String LOCAL_CONNECTOR_ADDRESS_PROP = "com.sun.management.jmxremote.localConnectorAddress"; private static final String JDP_DEFAULT_ADDRESS = "224.0.23.178"; private static final int JDP_DEFAULT_PORT = 7095; // The only active agent allowed private static JMXConnectorServer jmxServer = null; // The properties used to configure the server private static Properties configProps = null; // Parse string com.sun.management.prop=xxx,com.sun.management.prop=yyyy // and return property set if args is null or empty // return empty property set private static Properties parseString(String args) { Properties argProps = new Properties(); if (args != null && !args.trim().isEmpty()) { for (String option : args.split(",")) { String s[] = option.split("=", 2); String name = s[0].trim(); String value = (s.length > 1) ? s[1].trim() : ""; if (!name.startsWith("com.sun.management.")) { error(INVALID_OPTION, name); } argProps.setProperty(name, value); } } return argProps; } // invoked by -javaagent or -Dcom.sun.management.agent.class public static void premain(String args) throws Exception { agentmain(args); } // invoked by attach mechanism public static void agentmain(String args) throws Exception { if (args == null || args.length() == 0) { args = JMXREMOTE; // default to local management } Properties arg_props = parseString(args); // Read properties from the config file Properties config_props = new Properties(); String fname = arg_props.getProperty(CONFIG_FILE); readConfiguration(fname, config_props); // Arguments override config file config_props.putAll(arg_props); startAgent(config_props); } /* * Starts the local management agent. * This method is invoked by either startAgent method or * by the VM directly via jcmd ManagementAgent.start_local command. */ private static synchronized void startLocalManagementAgent() { Properties agentProps = VMSupport.getAgentProperties(); // start local connector if not started if (agentProps.get(LOCAL_CONNECTOR_ADDRESS_PROP) == null) { JMXConnectorServer cs = ConnectorBootstrap.startLocalConnectorServer(); String address = cs.getAddress().toString(); // Add the local connector address to the agent properties agentProps.put(LOCAL_CONNECTOR_ADDRESS_PROP, address); try { // export the address to the instrumentation buffer ConnectorAddressLink.export(address); } catch (Exception x) { // Connector server started but unable to export address // to instrumentation buffer - non-fatal error. warning(EXPORT_ADDRESS_FAILED, x.getMessage()); } } } /* * This method is invoked by the VM to start the remote management agent * via jcmd ManagementAgent.start command. */ private static synchronized void startRemoteManagementAgent(String args) throws Exception { if (jmxServer != null) { throw new RuntimeException(getText(INVALID_STATE, "Agent already started")); } try { Properties argProps = parseString(args); configProps = new Properties(); // Load the management properties from the config file // if config file is not specified readConfiguration implicitly // reads <java.home>/conf/management/management.properties String fname = System.getProperty(CONFIG_FILE); readConfiguration(fname, configProps); // management properties can be overridden by system properties // which take precedence Properties sysProps = System.getProperties(); synchronized (sysProps) { configProps.putAll(sysProps); } // if user specifies config file into command line for either // jcmd utilities or attach command it overrides properties set in // command line at the time of VM start String fnameUser = argProps.getProperty(CONFIG_FILE); if (fnameUser != null) { readConfiguration(fnameUser, configProps); } // arguments specified in command line of jcmd utilities // override both system properties and one set by config file // specified in jcmd command line configProps.putAll(argProps); // jcmd doesn't allow to change ThreadContentionMonitoring, but user // can specify this property inside config file, so enable optional // monitoring functionality if this property is set final String enableThreadContentionMonitoring = configProps.getProperty(ENABLE_THREAD_CONTENTION_MONITORING); if (enableThreadContentionMonitoring != null) { ManagementFactory.getThreadMXBean(). setThreadContentionMonitoringEnabled(true); } String jmxremotePort = configProps.getProperty(JMXREMOTE_PORT); if (jmxremotePort != null) { jmxServer = ConnectorBootstrap. startRemoteConnectorServer(jmxremotePort, configProps); startDiscoveryService(configProps); } else { throw new AgentConfigurationError(INVALID_JMXREMOTE_PORT, "No port specified"); } } catch (JdpException e) { error(e); } catch (AgentConfigurationError err) { error(err); } } private static synchronized void stopRemoteManagementAgent() throws Exception { JdpController.stopDiscoveryService(); if (jmxServer != null) { ConnectorBootstrap.unexportRegistry(); ConnectorAddressLink.unexportRemote(); // Attempt to stop already stopped agent // Don't cause any errors. jmxServer.stop(); jmxServer = null; configProps = null; } } private static synchronized String getManagementAgentStatus() throws Exception { return new TextStatusCollector().collect(); } private static void startAgent(Properties props) throws Exception { String jmxremote = props.getProperty(JMXREMOTE); String jmxremotePort = props.getProperty(JMXREMOTE_PORT); // Enable optional monitoring functionality if requested final String enableThreadContentionMonitoring = props.getProperty(ENABLE_THREAD_CONTENTION_MONITORING); if (enableThreadContentionMonitoring != null) { ManagementFactory.getThreadMXBean(). setThreadContentionMonitoringEnabled(true); } try { /* * If the jmxremote.port property is set then we start the * RMIConnectorServer for remote M&M. * * If the jmxremote or jmxremote.port properties are set then * we start a RMIConnectorServer for local M&M. The address * of this "local" server is exported as a counter to the jstat * instrumentation buffer. */ if (jmxremote != null || jmxremotePort != null) { if (jmxremotePort != null) { jmxServer = ConnectorBootstrap. startRemoteConnectorServer(jmxremotePort, props); startDiscoveryService(props); } startLocalManagementAgent(); } } catch (AgentConfigurationError e) { error(e); } catch (Exception e) { error(e); } } private static void startDiscoveryService(Properties props) throws IOException, JdpException { // Start discovery service if requested String discoveryPort = props.getProperty("com.sun.management.jdp.port"); String discoveryAddress = props.getProperty("com.sun.management.jdp.address"); String discoveryShouldStart = props.getProperty("com.sun.management.jmxremote.autodiscovery"); // Decide whether we should start autodicovery service. // To start autodiscovery following conditions should be met: // autodiscovery==true OR (autodicovery==null AND jdp.port != NULL) boolean shouldStart = false; if (discoveryShouldStart == null){ shouldStart = (discoveryPort != null); } else{ try{ shouldStart = Boolean.parseBoolean(discoveryShouldStart); } catch (NumberFormatException e) { throw new AgentConfigurationError(AGENT_EXCEPTION, "Couldn't parse autodiscovery argument"); } } if (shouldStart) { // port and address are required arguments and have no default values InetAddress address; try { address = (discoveryAddress == null) ? InetAddress.getByName(JDP_DEFAULT_ADDRESS) : InetAddress.getByName(discoveryAddress); } catch (UnknownHostException e) { throw new AgentConfigurationError(AGENT_EXCEPTION, e, "Unable to broadcast to requested address"); } int port = JDP_DEFAULT_PORT; if (discoveryPort != null) { try { port = Integer.parseInt(discoveryPort); } catch (NumberFormatException e) { throw new AgentConfigurationError(AGENT_EXCEPTION, "Couldn't parse JDP port argument"); } } // Get service URL to broadcast it Map<String,String> remoteProps = ConnectorAddressLink.importRemoteFrom(0); String jmxUrlStr = remoteProps.get("sun.management.JMXConnectorServer.0.remoteAddress"); String instanceName = props.getProperty("com.sun.management.jdp.name"); JdpController.startDiscoveryService(address, port, instanceName, jmxUrlStr); } } public static Properties loadManagementProperties() { Properties props = new Properties(); // Load the management properties from the config file String fname = System.getProperty(CONFIG_FILE); readConfiguration(fname, props); // management properties can be overridden by system properties // which take precedence Properties sysProps = System.getProperties(); synchronized (sysProps) { props.putAll(sysProps); } return props; } public static synchronized Properties getManagementProperties() { if (mgmtProps == null) { String configFile = System.getProperty(CONFIG_FILE); String jmxremote = System.getProperty(JMXREMOTE); String jmxremotePort = System.getProperty(JMXREMOTE_PORT); if (configFile == null && jmxremote == null && jmxremotePort == null) { // return if out-of-the-management option is not specified return null; } mgmtProps = loadManagementProperties(); } return mgmtProps; } // read config file and initialize the properties private static void readConfiguration(String fname, Properties p) { if (fname == null) { String home = System.getProperty("java.home"); if (home == null) { throw new Error("Can't find java.home ??"); } StringBuilder defaultFileName = new StringBuilder(home); defaultFileName.append(File.separator).append("conf"); defaultFileName.append(File.separator).append("management"); defaultFileName.append(File.separator).append("management.properties"); // Set file name fname = defaultFileName.toString(); } final File configFile = new File(fname); if (!configFile.exists()) { error(CONFIG_FILE_NOT_FOUND, fname); } InputStream in = null; try { in = new FileInputStream(configFile); BufferedInputStream bin = new BufferedInputStream(in); p.load(bin); } catch (FileNotFoundException e) { error(CONFIG_FILE_OPEN_FAILED, e.getMessage()); } catch (IOException e) { error(CONFIG_FILE_OPEN_FAILED, e.getMessage()); } catch (SecurityException e) { error(CONFIG_FILE_ACCESS_DENIED, fname); } finally { if (in != null) { try { in.close(); } catch (IOException e) { error(CONFIG_FILE_CLOSE_FAILED, fname); } } } }
This method is invoked by the VM to start the management agent when -Dcom.sun.management.* is set during startup.
/** * This method is invoked by the VM to start the management agent * when -Dcom.sun.management.* is set during startup. */
public static void startAgent() throws Exception { String prop = System.getProperty("com.sun.management.agent.class"); // -Dcom.sun.management.agent.class not set so read management // properties and start agent if (prop == null) { // initialize management properties Properties props = getManagementProperties(); if (props != null) { startAgent(props); } return; } // -Dcom.sun.management.agent.class=<agent classname>:<agent args> String[] values = prop.split(":"); if (values.length < 1 || values.length > 2) { error(AGENT_CLASS_INVALID, "\"" + prop + "\""); } String cname = values[0]; String args = (values.length == 2 ? values[1] : null); if (cname == null || cname.length() == 0) { error(AGENT_CLASS_INVALID, "\"" + prop + "\""); } if (cname != null) { try { // Instantiate the named class. // invoke the premain(String args) method Class<?> clz = ClassLoader.getSystemClassLoader().loadClass(cname); Method premain = clz.getMethod("premain", new Class<?>[]{String.class}); premain.invoke(null, /* static */ new Object[]{args}); } catch (ClassNotFoundException ex) { error(AGENT_CLASS_NOT_FOUND, "\"" + cname + "\""); } catch (NoSuchMethodException ex) { error(AGENT_CLASS_PREMAIN_NOT_FOUND, "\"" + cname + "\""); } catch (SecurityException ex) { error(AGENT_CLASS_ACCESS_DENIED); } catch (Exception ex) { String msg = (ex.getCause() == null ? ex.getMessage() : ex.getCause().getMessage()); error(AGENT_CLASS_FAILED, msg); } } } public static void error(String key) { String keyText = getText(key); System.err.print(getText("agent.err.error") + ": " + keyText); throw new RuntimeException(keyText); } public static void error(String key, String message) { String keyText = getText(key); System.err.print(getText("agent.err.error") + ": " + keyText); System.err.println(": " + message); throw new RuntimeException(keyText + ": " + message); } public static void error(Exception e) { e.printStackTrace(); System.err.println(getText(AGENT_EXCEPTION) + ": " + e.toString()); throw new RuntimeException(e); } public static void error(AgentConfigurationError e) { String keyText = getText(e.getError()); String[] params = e.getParams(); System.err.print(getText("agent.err.error") + ": " + keyText); if (params != null && params.length != 0) { System.err.println(": " + String.join(" ", params)); } e.printStackTrace(); throw new RuntimeException(e); } public static void warning(String key, String message) { System.err.print(getText("agent.err.warning") + ": " + getText(key)); System.err.println(": " + message); } private static void initResource() { try { messageRB = ResourceBundle.getBundle("jdk.internal.agent.resources.agent"); } catch (MissingResourceException e) { throw new Error("Fatal: Resource for management agent is missing"); } } public static String getText(String key) { if (messageRB == null) { initResource(); } try { return messageRB.getString(key); } catch (MissingResourceException e) { return "Missing management agent resource bundle: key = \"" + key + "\""; } } public static String getText(String key, String... args) { if (messageRB == null) { initResource(); } String format = messageRB.getString(key); if (format == null) { format = "missing resource key: key = \"" + key + "\", " + "arguments = \"{0}\", \"{1}\", \"{2}\""; } return MessageFormat.format(format, (Object[]) args); } }