org.jikesrvm.runtime

Class DynamicLibrary

java.lang.Object

org.jikesrvm.runtime.DynamicLibrary

public final class DynamicLibrary
extends Object

Interface to the dynamic libraries of our underlying operating system.

Field Summary

Fields

Modifier and Type	Field and Description
private static ImmutableEntryHashMapRVM<String,DynamicLibrary>	dynamicLibraries Currently loaded dynamic libraries.
private Address	jniOnLoad Address of JNI_OnLoad method
private Address	jniOnUnload Address of JNI_OnUnLoad
private Address	libHandler Value returned from dlopen
private String	libName The name of the library

Constructor Summary

Constructors

Modifier	Constructor and Description
private	DynamicLibrary(String libName, Address libHandler) Maintain a loaded library, call it's JNI_OnLoad function if present

Method Summary

Modifier and Type	Method and Description
static void	boot() Add symbol for the bootloader to find symbols within it.
private void	callOnLoad() Called after we've successfully loaded the shared library
private static void	checkJNIVersion(int version) Check JNI version is ≥ 1 and ≤ 1.4 and if not throw an UnsatisfiedLinkError
void	clean() Tell the operating system to remove the dynamic library from the system space.
private Address	getJNI_OnLoad() Get the unique JNI_OnLoad symbol associated with this library
private Address	getJNI_OnUnload() Get the unique JNI_OnUnload symbol associated with this library
String	getLibName()
Address	getSymbol(String symbolName) look up this dynamic library for a symbol
static int	load(String libName) Load a dynamic library
static Address	resolveSymbol(String symbol) Resolves a symbol to an address in a currently loaded dynamic library.
private static int	runJNI_OnLoad(Address JNI_OnLoadAddress) Method call to run the onload method.
String	toString()
void	unload() unload a dynamic library

Methods inherited from class java.lang.Object

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

Field Detail

dynamicLibraries

private static final ImmutableEntryHashMapRVM<String,DynamicLibrary> dynamicLibraries

Currently loaded dynamic libraries.

libName

private final String libName

The name of the library

libHandler

private final Address libHandler

Value returned from dlopen

jniOnLoad

private final Address jniOnLoad

Address of JNI_OnLoad method

jniOnUnload

private final Address jniOnUnload

Address of JNI_OnUnLoad

Constructor Detail

DynamicLibrary

private DynamicLibrary(String libName,
                       Address libHandler)

Maintain a loaded library, call it's JNI_OnLoad function if present

Parameters:

libName - library name

libHandler - handle of loaded library

Method Detail

boot

public static void boot()

Add symbol for the bootloader to find symbols within it.

getJNI_OnLoad

private Address getJNI_OnLoad()

Get the unique JNI_OnLoad symbol associated with this library

Returns:

JNI_OnLoad address or zero if not present

getJNI_OnUnload

private Address getJNI_OnUnload()

Get the unique JNI_OnUnload symbol associated with this library

Returns:

JNI_OnUnload address or zero if not present

callOnLoad

private void callOnLoad()

Called after we've successfully loaded the shared library

runJNI_OnLoad

private static int runJNI_OnLoad(Address JNI_OnLoadAddress)

Method call to run the onload method. Performed as a native method as the JNI_OnLoad method may contain JNI calls and we need the RVMThread of the JNIEnv to be correctly populated (this wouldn't happen with a SysCall)

Parameters:

JNI_OnLoadAddress - address of JNI_OnLoad function

Returns:

the JNI version returned by the JNI_OnLoad function

checkJNIVersion

private static void checkJNIVersion(int version)

Check JNI version is ≥ 1 and ≤ 1.4 and if not throw an UnsatisfiedLinkError

Parameters:

version - to check

getLibName

public String getLibName()

Returns:

the true name of the dynamic library

getSymbol

public Address getSymbol(String symbolName)

look up this dynamic library for a symbol

Parameters:

symbolName - symbol name

Returns:

The Address of the symbol system handler (or an address of a PowerPC Linkage triplet). (-1: not found or couldn't be created)

unload

public void unload()

unload a dynamic library

clean

public void clean()

Tell the operating system to remove the dynamic library from the system space.

toString

public String toString()

Overrides:

toString in class Object

load

public static int load(String libName)

Load a dynamic library

Parameters:

libName - the name of the library to load.

Returns:

0 on failure, 1 on success

resolveSymbol

public static Address resolveSymbol(String symbol)

Resolves a symbol to an address in a currently loaded dynamic library.

Parameters:

symbol - the symbol to resolves

Returns:

the address of the symbol of Address.zero() if it cannot be resolved