Module org.elasticsearch.entitlement

Package org.elasticsearch.entitlement.initialization

Class EntitlementInitialization

java.lang.Object

org.elasticsearch.entitlement.initialization.EntitlementInitialization

public class EntitlementInitialization
extends Object

Called by the agent during agentmain to configure the entitlement system, instantiate and configure an EntitlementChecker, make it available to the bootstrap library via checker(), and then install the Instrumenter to begin injecting our instrumentation.

Constructor Summary

Constructors

Constructor	Description
EntitlementInitialization()

Method Summary

Modifier and Type	Method	Description
static EntitlementChecker	checker()
static void	initialize(Instrumentation inst)	Initializes the Entitlement system: Finds the version-specific subclass of EntitlementChecker to use Builds the set of methods to instrument using InstrumentationService.lookupMethods(java.lang.Class<?>) Augment this set “dynamically” using InstrumentationService.lookupImplementationMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>, java.lang.Class<?>, java.lang.String, java.lang.Class<?>...) Creates an Instrumenter via InstrumentationService.newInstrumenter(java.lang.Class<?>, java.util.Map<org.elasticsearch.entitlement.instrumentation.MethodKey, org.elasticsearch.entitlement.instrumentation.CheckMethod>), and adds a new Transformer (derived from ClassFileTransformer) that uses it.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

EntitlementInitialization

public EntitlementInitialization()

Method Details

checker

public static EntitlementChecker checker()

initialize

public static void initialize(Instrumentation inst)
                       throws Exception

Initializes the Entitlement system:

1. Finds the version-specific subclass of EntitlementChecker to use
2. Builds the set of methods to instrument using InstrumentationService.lookupMethods(java.lang.Class<?>)
3. Augment this set “dynamically” using InstrumentationService.lookupImplementationMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>, java.lang.Class<?>, java.lang.String, java.lang.Class<?>...)
4. Creates an Instrumenter via InstrumentationService.newInstrumenter(java.lang.Class<?>, java.util.Map<org.elasticsearch.entitlement.instrumentation.MethodKey, org.elasticsearch.entitlement.instrumentation.CheckMethod>), and adds a new Transformer (derived from ClassFileTransformer) that uses it. Transformers are invoked when a class is about to load, after its bytes have been deserialized to memory but before the class is initialized.
5. Re-transforms all already loaded classes: we force the Instrumenter to run on classes that might have been already loaded before entitlement initialization by calling the Instrumentation.retransformClasses(java.lang.Class<?>...) method on all classes that were already loaded.

The third step is needed as the JDK exposes some API through interfaces that have different (internal) implementations depending on the JVM host platform. As we cannot instrument an interfaces, we find its concrete implementation. A prime example is FileSystemProvider, which has different implementations (e.g. UnixFileSystemProvider or WindowsFileSystemProvider). At runtime, we find the implementation class which is currently used by the JVM, and add its methods to the set of methods to instrument. See e.g. fileSystemProviderChecks().

NOTE: this method is referenced by the agent reflectively

Parameters:

inst - the JVM instrumentation class instance

Throws:

Exception