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/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
package io.opentelemetry.javaagent.bootstrap;
import io.opentelemetry.instrumentation.api.internal.ConfigPropertiesUtil;
import java.io.File;
import java.lang.instrument.Instrumentation;
import java.lang.reflect.Constructor;
import java.security.PrivilegedAction;
import java.security.PrivilegedExceptionAction;
import javax.annotation.Nullable;
/**
* Agent start up logic.
*
* This class is loaded and called by {@code io.opentelemetry.javaagent.OpenTelemetryAgent}
*
*
The intention is for this class to be loaded by bootstrap class loader to make sure we have
* unimpeded access to the rest of agent parts.
*/
public final class AgentInitializer {
@Nullable private static ClassLoader agentClassLoader = null;
@Nullable private static AgentStarter agentStarter = null;
private static boolean isSecurityManagerSupportEnabled = false;
private static volatile boolean agentStarted = false;
public static void initialize(Instrumentation inst, File javaagentFile, boolean fromPremain)
throws Exception {
if (agentClassLoader != null) {
return;
}
// we expect that at this point agent jar has been appended to boot class path and all agent
// classes are loaded in boot loader
if (AgentInitializer.class.getClassLoader() != null) {
throw new IllegalStateException("agent initializer should be loaded in boot loader");
}
isSecurityManagerSupportEnabled = isSecurityManagerSupportEnabled();
// this call deliberately uses anonymous class instead of lambda because using lambdas too
// early on early jdk8 (see isEarlyOracle18 method) causes jvm to crash. See CrashEarlyJdk8Test.
execute(
new PrivilegedExceptionAction() {
@Override
public Void run() throws Exception {
agentClassLoader = createAgentClassLoader("inst", javaagentFile);
agentStarter = createAgentStarter(agentClassLoader, inst, javaagentFile);
if (!fromPremain || !delayAgentStart()) {
agentStarter.start();
agentStarted = true;
}
return null;
}
});
}
private static void execute(PrivilegedExceptionAction action) throws Exception {
// When security manager support is enabled we use doPrivileged even if security manager is not
// present because security manager could be installed later. ByteBuddy initialization captures
// the access control context used during transformation. If we don't use doPrivileged here then
// that context will not have the privileges if security manager is installed later.
if (isSecurityManagerSupportEnabled) {
doPrivilegedExceptionAction(action);
} else {
action.run();
}
}
private static boolean isSecurityManagerSupportEnabled() {
return getBoolean("otel.javaagent.experimental.security-manager-support.enabled", false);
}
private static boolean getBoolean(String property, boolean defaultValue) {
// this call deliberately uses anonymous class instead of lambda because using lambdas too
// early on early jdk8 (see isEarlyOracle18 method) causes jvm to crash. See CrashEarlyJdk8Test.
return doPrivileged(
new PrivilegedAction() {
@Override
public Boolean run() {
return ConfigPropertiesUtil.getBoolean(property, defaultValue);
}
});
}
@SuppressWarnings("removal") // AccessController is deprecated for removal
private static T doPrivilegedExceptionAction(PrivilegedExceptionAction action)
throws Exception {
return java.security.AccessController.doPrivileged(action);
}
@SuppressWarnings("removal") // AccessController is deprecated for removal
private static T doPrivileged(PrivilegedAction action) {
return java.security.AccessController.doPrivileged(action);
}
/**
* Test whether we are running on oracle 1.8 before 1.8.0_40.
*
* @return true for oracle 1.8 before 1.8.0_40
*/
private static boolean isEarlyOracle18() {
// Java HotSpot(TM) 64-Bit Server VM or OpenJDK 64-Bit Server VM
String vmName = System.getProperty("java.vm.name");
if (!vmName.contains("HotSpot") && !vmName.contains("OpenJDK")) {
return false;
}
// 1.8.0_31
String javaVersion = System.getProperty("java.version");
if (!javaVersion.startsWith("1.8")) {
return false;
}
int index = javaVersion.indexOf('_');
if (index == -1) {
return false;
}
String minorVersion = javaVersion.substring(index + 1);
try {
int version = Integer.parseInt(minorVersion);
if (version >= 40) {
return false;
}
} catch (NumberFormatException exception) {
return false;
}
return true;
}
private static boolean delayAgentStart() {
if (!isEarlyOracle18()) {
return false;
}
return agentStarter.delayStart();
}
/**
* Call to this method is inserted into {@code sun.launcher.LauncherHelper.checkAndLoadMain()}.
*/
@SuppressWarnings("unused")
public static void delayedStartHook() throws Exception {
// this call deliberately uses anonymous class instead of lambda because using lambdas too
// early on early jdk8 (see isEarlyOracle18 method) causes jvm to crash. See CrashEarlyJdk8Test.
execute(
new PrivilegedExceptionAction() {
@Override
public Void run() {
agentStarter.start();
agentStarted = true;
return null;
}
});
}
/**
* Check whether agent has started or not along with VM.
*
* This method is used by
* io.opentelemetry.javaagent.tooling.AgentStarterImpl#InetAddressClassFileTransformer internally
* to check whether agent has started.
*
* @param vmStarted flag about whether VM has started or not.
* @return {@code true} if agent has started or not along with VM, {@code false} otherwise.
*/
@SuppressWarnings("unused")
public static boolean isAgentStarted(boolean vmStarted) {
return vmStarted && agentStarted;
}
public static ClassLoader getExtensionsClassLoader() {
// agentStarter can be null when running tests
return agentStarter != null ? agentStarter.getExtensionClassLoader() : null;
}
/**
* Create the agent class loader. This must be called after the bootstrap jar has been appended to
* the bootstrap classpath.
*
* @param innerJarFilename Filename of internal jar to use for the classpath of the agent class
* loader
* @return Agent Classloader
*/
private static ClassLoader createAgentClassLoader(String innerJarFilename, File javaagentFile) {
return new AgentClassLoader(javaagentFile, innerJarFilename, isSecurityManagerSupportEnabled);
}
private static AgentStarter createAgentStarter(
ClassLoader agentClassLoader, Instrumentation instrumentation, File javaagentFile)
throws Exception {
Class starterClass =
agentClassLoader.loadClass("io.opentelemetry.javaagent.tooling.AgentStarterImpl");
Constructor constructor =
starterClass.getDeclaredConstructor(Instrumentation.class, File.class, boolean.class);
return (AgentStarter)
constructor.newInstance(instrumentation, javaagentFile, isSecurityManagerSupportEnabled);
}
private AgentInitializer() {}
}