co.elastic.apm.attach.bytebuddy.agent.VirtualMachine Maven / Gradle / Ivy
/*
* Copyright 2014 - Present Rafael Winterhalter
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package co.elastic.apm.attach.bytebuddy.agent;
import com.sun.jna.*;
import com.sun.jna.platform.win32.*;
import com.sun.jna.ptr.IntByReference;
import com.sun.jna.win32.StdCallLibrary;
import com.sun.jna.win32.W32APIOptions;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
import co.elastic.apm.attach.bytebuddy.agent.utility.nullability.MaybeNull;
import co.elastic.apm.attach.bytebuddy.agent.utility.nullability.UnknownNull;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.channels.FileLock;
import java.security.PrivilegedAction;
import java.security.SecureRandom;
import java.util.*;
import java.util.concurrent.TimeUnit;
/**
*
* An implementation for attachment on a virtual machine. This interface mimics the tooling API's virtual
* machine interface to allow for similar usage by {@link ByteBuddyAgent} where all calls are made via
* reflection such that this structural typing suffices for interoperability.
*
*
* Note: Implementations are required to declare a static method {@code attach(String)} returning an
* instance of a class that declares the methods defined by {@link VirtualMachine}.
*
*/
public interface VirtualMachine {
/**
* Loads the target VMs system properties.
*
* @return The target VM properties.
* @throws IOException If an I/O exception occurs.
*/
Properties getSystemProperties() throws IOException;
/**
* Loads the target VMs agent properties.
*
* @return The target VM properties.
* @throws IOException If an I/O exception occurs.
*/
Properties getAgentProperties() throws IOException;
/**
* Loads an agent into the represented virtual machine.
*
* @param jarFile The jar file to attach.
* @throws IOException If an I/O exception occurs.
*/
void loadAgent(String jarFile) throws IOException;
/**
* Loads an agent into the represented virtual machine.
*
* @param jarFile The jar file to attach.
* @param argument The argument to provide or {@code null} if no argument should be provided.
* @throws IOException If an I/O exception occurs.
*/
void loadAgent(String jarFile, @MaybeNull String argument) throws IOException;
/**
* Loads a native agent into the represented virtual machine.
*
* @param path The agent path.
* @throws IOException If an I/O exception occurs.
*/
void loadAgentPath(String path) throws IOException;
/**
* Loads a native agent into the represented virtual machine.
*
* @param path The agent path.
* @param argument The argument to provide or {@code null} if no argument should be provided.
* @throws IOException If an I/O exception occurs.
*/
void loadAgentPath(String path, @MaybeNull String argument) throws IOException;
/**
* Loads a native agent library into the represented virtual machine.
*
* @param library The agent library.
* @throws IOException If an I/O exception occurs.
*/
void loadAgentLibrary(String library) throws IOException;
/**
* Loads a native agent library into the represented virtual machine.
*
* @param library The agent library.
* @param argument The argument to provide or {@code null} if no argument should be provided.
* @throws IOException If an I/O exception occurs.
*/
void loadAgentLibrary(String library, @MaybeNull String argument) throws IOException;
/**
* Starts a JMX management agent.
*
* @param properties The properties to transfer to the JMX agent.
* @throws IOException If an I/O error occurs.
*/
void startManagementAgent(Properties properties) throws IOException;
/**
* Starts a local management agent.
*
* @return The local connector address.
* @throws IOException If an I/O error occurs.
*/
String startLocalManagementAgent() throws IOException;
/**
* Detaches this virtual machine representation.
*
* @throws IOException If an I/O exception occurs.
*/
void detach() throws IOException;
/**
* A resolver for the current VM's virtual machine attachment emulation.
*/
enum Resolver implements PrivilegedAction> {
/**
* The singleton instance.
*/
INSTANCE;
/**
* {@inheritDoc}
*/
public Class run() {
try {
Class.forName("com.sun.jna.Platform");
} catch (ClassNotFoundException exception) {
throw new IllegalStateException("Optional JNA dependency is not available", exception);
}
return System.getProperty("java.vm.name", "").toUpperCase(Locale.US).contains("J9")
? ForOpenJ9.class
: ForHotSpot.class;
}
}
/**
* An abstract base implementation for a virtual machine.
*/
abstract class AbstractBase implements VirtualMachine {
/**
* {@inheritDoc}
*/
public void loadAgent(String jarFile) throws IOException {
loadAgent(jarFile, null);
}
/**
* {@inheritDoc}
*/
public void loadAgentPath(String path) throws IOException {
loadAgentPath(path, null);
}
/**
* {@inheritDoc}
*/
public void loadAgentLibrary(String library) throws IOException {
loadAgentLibrary(library, null);
}
}
/**
* A virtual machine attachment implementation for a HotSpot VM or any compatible JVM.
*/
class ForHotSpot extends AbstractBase {
/**
* The protocol version to use for communication.
*/
private static final String PROTOCOL_VERSION = "1";
/**
* The {@code load} command.
*/
private static final String LOAD_COMMAND = "load";
/**
* The {@code instrument} command.
*/
private static final String INSTRUMENT_COMMAND = "instrument";
/**
* A delimiter to be used for attachment.
*/
private static final String ARGUMENT_DELIMITER = "=";
/**
* The virtual machine connection.
*/
private final Connection connection;
/**
* Creates a new virtual machine connection for HotSpot.
*
* @param connection The virtual machine connection.
*/
protected ForHotSpot(Connection connection) {
this.connection = connection;
}
/**
* Attaches to the supplied process id using the default JNA implementation.
*
* @param processId The process id.
* @return A suitable virtual machine implementation.
* @throws IOException If an IO exception occurs during establishing the connection.
*/
public static VirtualMachine attach(String processId) throws IOException {
if (Platform.isWindows()) {
return attach(processId, new Connection.ForJnaWindowsNamedPipe.Factory());
} else if (Platform.isSolaris()) {
return attach(processId, new Connection.ForJnaSolarisDoor.Factory(15, 100, TimeUnit.MILLISECONDS));
} else {
return attach(processId, Connection.ForJnaPosixSocket.Factory.withDefaultTemporaryFolder(15, 100, TimeUnit.MILLISECONDS));
}
}
/**
* Attaches to the supplied process id using the supplied connection factory.
*
* @param processId The process id.
* @param connectionFactory The connection factory to use.
* @return A suitable virtual machine implementation.
* @throws IOException If an IO exception occurs during establishing the connection.
*/
public static VirtualMachine attach(String processId, Connection.Factory connectionFactory) throws IOException {
return new ForHotSpot(connectionFactory.connect(processId));
}
/**
* Checks the header of a response.
*
* @param response The response to check the header for.
* @throws IOException If an I/O exception occurs.
*/
private static void checkHeader(Connection.Response response) throws IOException {
byte[] buffer = new byte[1];
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
int length;
while ((length = response.read(buffer)) != -1) {
if (length > 0) {
if (buffer[0] == '\n') {
break;
}
outputStream.write(buffer[0]);
}
}
switch (Integer.parseInt(outputStream.toString("UTF-8"))) {
case 0:
return;
case 101:
throw new IOException("Protocol mismatch with target VM");
default:
buffer = new byte[1024];
outputStream = new ByteArrayOutputStream();
while ((length = response.read(buffer)) != -1) {
outputStream.write(buffer, 0, length);
}
throw new IllegalStateException(outputStream.toString("UTF-8"));
}
}
/**
* {@inheritDoc}
*/
public Properties getSystemProperties() throws IOException {
return getProperties("properties");
}
/**
* {@inheritDoc}
*/
public Properties getAgentProperties() throws IOException {
return getProperties("agentProperties");
}
/**
* Loads properties of the target VM.
*
* @param command The command for fetching properties.
* @return The read properties.
* @throws IOException If an I/O exception occurs.
*/
private Properties getProperties(String command) throws IOException {
Connection.Response response = connection.execute(PROTOCOL_VERSION, command, null, null, null);
try {
checkHeader(response);
byte[] buffer = new byte[1024];
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
int length;
while ((length = response.read(buffer)) != -1) {
outputStream.write(buffer, 0, length);
}
Properties properties = new Properties();
properties.load(new ByteArrayInputStream(outputStream.toByteArray()));
return properties;
} finally {
response.close();
}
}
/**
* {@inheritDoc}
*/
public void loadAgent(String jarFile, @MaybeNull String argument) throws IOException {
load(jarFile, false, argument);
}
/**
* {@inheritDoc}
*/
public void loadAgentPath(String path, @MaybeNull String argument) throws IOException {
load(path, true, argument);
}
/**
* {@inheritDoc}
*/
public void loadAgentLibrary(String library, @MaybeNull String argument) throws IOException {
load(library, false, argument);
}
/**
* Loads an agent by the given command.
*
* @param file The Java agent or library to be loaded.
* @param absolute {@code true} if the agent location is absolute.
* @param argument The argument to the agent or {@code null} if no argument is given.
* @throws IOException If an I/O exception occurs.
*/
protected void load(String file, boolean absolute, @MaybeNull String argument) throws IOException {
Connection.Response response = connection.execute(PROTOCOL_VERSION, LOAD_COMMAND, INSTRUMENT_COMMAND, Boolean.toString(absolute), (argument == null
? file
: file + ARGUMENT_DELIMITER + argument));
try {
checkHeader(response);
} finally {
response.close();
}
}
/**
* {@inheritDoc}
*/
public void startManagementAgent(Properties properties) throws IOException {
StringBuilder stringBuilder = new StringBuilder("ManagementAgent.start ");
boolean first = true;
for (Map.Entry entry : properties.entrySet()) {
if (!(entry.getKey() instanceof String) || !((String) entry.getKey()).startsWith("com.sun.management.")) {
throw new IllegalArgumentException("Illegal property name: " + entry.getKey());
} else if (first) {
first = false;
} else {
stringBuilder.append(' ');
}
stringBuilder.append(((String) entry.getKey()).substring("com.sun.management.".length())).append('=');
String value = entry.getValue().toString();
if (value.contains(" ")) {
stringBuilder.append('\'').append(value).append('\'');
} else {
stringBuilder.append(value);
}
}
Connection.Response response = connection.execute(PROTOCOL_VERSION, "jcmd", stringBuilder.toString(), null, null);
try {
checkHeader(response);
} finally {
response.close();
}
}
/**
* {@inheritDoc}
*/
public String startLocalManagementAgent() throws IOException {
Connection.Response response = connection.execute(PROTOCOL_VERSION, "jcmd", "ManagementAgent.start_local", null, null);
try {
checkHeader(response);
return getAgentProperties().getProperty("com.sun.management.jmxremote.localConnectorAddress");
} finally {
response.close();
}
}
/**
* {@inheritDoc}
*/
public void detach() throws IOException {
connection.close();
}
/**
* Represents a connection to a virtual machine.
*/
public interface Connection extends Closeable {
/**
* Executes a command on the current connection.
*
* @param protocol The target VMs protocol version for the attach API.
* @param argument The arguments to send to the target VM.
* @return The response of the target JVM.
* @throws IOException If an I/O error occurred.
*/
Response execute(String protocol, String... argument) throws IOException;
/**
* A response to an execution command to a VM.
*/
interface Response extends Closeable {
/**
* Reads a buffer from the target VM.
*
* @param buffer The buffer to read to.
* @return The bytes read or {@code -1} if no more bytes could be read.
* @throws IOException If an I/O exception occurred.
*/
int read(byte[] buffer) throws IOException;
}
/**
* A factory for creating connections to virtual machines.
*/
interface Factory {
/**
* Connects to the supplied process.
*
* @param processId The process id.
* @return The connection to the virtual machine with the supplied process id.
* @throws IOException If an I/O exception occurs during connecting to the targeted VM.
*/
Connection connect(String processId) throws IOException;
/**
* A factory for attaching via a socket file.
*/
abstract class ForSocketFile implements Factory {
/**
* The name prefix for a socket.
*/
private static final String SOCKET_FILE_PREFIX = ".java_pid";
/**
* The name prefix for an attachment file indicator.
*/
private static final String ATTACH_FILE_PREFIX = ".attach_pid";
/**
* The temporary directory to use.
*/
private final String temporaryDirectory;
/**
* The maximum amount of attempts for checking the establishment of a socket connection.
*/
private final int attempts;
/**
* The pause between two checks for an established socket connection.
*/
private final long pause;
/**
* The time unit of the pause time.
*/
private final TimeUnit timeUnit;
/**
* Creates a connection factory for creating a socket connection via a file.
*
* @param temporaryDirectory The temporary directory to use.
* @param attempts The maximum amount of attempts for checking the establishment of a socket connection.
* @param pause The pause between two checks for an established socket connection.
* @param timeUnit The time unit of the pause time.
*/
protected ForSocketFile(String temporaryDirectory, int attempts, long pause, TimeUnit timeUnit) {
this.temporaryDirectory = temporaryDirectory;
this.attempts = attempts;
this.pause = pause;
this.timeUnit = timeUnit;
}
/**
* {@inheritDoc}
*/
@SuppressFBWarnings(value = "DMI_HARDCODED_ABSOLUTE_FILENAME", justification = "File name convention is specified.")
public Connection connect(String processId) throws IOException {
File socket = new File(temporaryDirectory, SOCKET_FILE_PREFIX + processId);
if (!socket.exists()) {
String target = ATTACH_FILE_PREFIX + processId, path = "/proc/" + processId + "/cwd/" + target;
File attachFile = new File(path);
try {
if (!attachFile.createNewFile() && !attachFile.isFile()) {
throw new IllegalStateException("Could not create attach file: " + attachFile);
}
} catch (IOException ignored) {
attachFile = new File(temporaryDirectory, target);
if (!attachFile.createNewFile() && !attachFile.isFile()) {
throw new IllegalStateException("Could not create attach file: " + attachFile);
}
}
try {
kill(processId, 3);
int attempts = this.attempts;
while (!socket.exists() && attempts-- > 0) {
timeUnit.sleep(pause);
}
if (!socket.exists()) {
throw new IllegalStateException("Target VM did not respond: " + processId);
}
} catch (InterruptedException exception) {
Thread.currentThread().interrupt();
throw new IllegalStateException(exception);
} finally {
if (!attachFile.delete()) {
attachFile.deleteOnExit();
}
}
}
return doConnect(socket);
}
/**
* Sends a kill signal to the target process.
*
* @param processId The process id.
* @param signal The signal to send.
*/
protected abstract void kill(String processId, int signal);
/**
* Connects to the supplied POSIX socket.
*
* @param socket The socket to connect to.
* @return An active connection to the supplied socket.
* @throws IOException If an error occurs during connection.
*/
protected abstract Connection doConnect(File socket) throws IOException;
}
}
/**
* A connection that is represented by a byte channel that is persistent during communication.
*
* @param The connection representation.
*/
abstract class OnPersistentByteChannel implements Connection {
/**
* A blank line argument.
*/
private static final byte[] BLANK = new byte[]{0};
/**
* {@inheritDoc}
*/
public Connection.Response execute(String protocol, String... argument) throws IOException {
T connection = connect();
try {
write(connection, protocol.getBytes("UTF-8"));
write(connection, BLANK);
for (String anArgument : argument) {
if (anArgument != null) {
write(connection, anArgument.getBytes("UTF-8"));
}
write(connection, BLANK);
}
return new Response(connection);
} catch (Throwable throwable) {
close(connection);
if (throwable instanceof RuntimeException) {
throw (RuntimeException) throwable;
} else if (throwable instanceof IOException) {
throw (IOException) throwable;
} else {
throw new IllegalStateException(throwable);
}
}
}
/**
* A response of a persistent byte channel.
*/
private class Response implements Connection.Response {
/**
* The connection representing this response.
*/
private final T connection;
/**
* Creates a new response for a persistent byte channel.
*
* @param connection The connection representing this response.
*/
private Response(T connection) {
this.connection = connection;
}
/**
* {@inheritDoc}
*/
public int read(byte[] buffer) throws IOException {
return OnPersistentByteChannel.this.read(connection, buffer);
}
/**
* {@inheritDoc}
*/
public void close() throws IOException {
OnPersistentByteChannel.this.close(connection);
}
}
/**
* Creates a new connection to the target VM.
*
* @return Returns a new connection to the target VM.
* @throws IOException If an I/O exception occurs.
*/
protected abstract T connect() throws IOException;
/**
* Closes the connection to the target VM.
*
* @param connection The connection to close.
* @throws IOException If an I/O exception occurs.
*/
protected abstract void close(T connection) throws IOException;
/**
* Writes to the target VM.
*
* @param connection The connection to write to.
* @param buffer The buffer to write to.
* @throws IOException If an I/O exception occurs during writing.
*/
protected abstract void write(T connection, byte[] buffer) throws IOException;
/**
* Reads from the target VM.
*
* @param connection The connection to read from.
* @param buffer The buffer to store the result in.
* @return The number of byte that were read.
* @throws IOException If an I/O exception occurs.
*/
protected abstract int read(T connection, byte[] buffer) throws IOException;
}
/**
* Implements a connection for a Posix socket in JNA.
*/
class ForJnaPosixSocket extends OnPersistentByteChannel {
/**
* The JNA library to use.
*/
private final PosixLibrary library;
/**
* The POSIX socket.
*/
private final File socket;
/**
* Creates a connection for a virtual posix socket implemented in JNA.
*
* @param library The JNA library to use.
* @param socket The POSIX socket.
*/
protected ForJnaPosixSocket(PosixLibrary library, File socket) {
this.library = library;
this.socket = socket;
}
@Override
protected Integer connect() {
int handle = library.socket(1, 1, 0);
try {
PosixLibrary.SocketAddress address = new PosixLibrary.SocketAddress();
try {
address.setPath(socket.getAbsolutePath());
library.connect(handle, address, address.size());
return handle;
} finally {
address = null;
}
} catch (RuntimeException exception) {
library.close(handle);
throw exception;
}
}
@Override
protected int read(Integer handle, byte[] buffer) {
int read = library.read(handle, ByteBuffer.wrap(buffer), buffer.length);
return read == 0 ? -1 : read;
}
@Override
protected void write(Integer handle, byte[] buffer) {
library.write(handle, ByteBuffer.wrap(buffer), buffer.length);
}
@Override
protected void close(Integer handle) {
library.close(handle);
}
/**
* {@inheritDoc}
*/
public void close() {
/* do nothing */
}
/**
* A JNA library binding for Posix sockets.
*/
protected interface PosixLibrary extends Library {
/**
* Sends a kill command.
*
* @param processId The process id to kill.
* @param signal The signal to send.
* @return The return code.
* @throws LastErrorException If an error occurs.
*/
int kill(int processId, int signal) throws LastErrorException;
/**
* Creates a POSIX socket connection.
*
* @param domain The socket's domain.
* @param type The socket's type.
* @param protocol The protocol version.
* @return A handle to the socket that was created or {@code 0} if no socket could be created.
* @throws LastErrorException If an error occurs.
*/
int socket(int domain, int type, int protocol) throws LastErrorException;
/**
* Connects a socket connection.
*
* @param handle The socket's handle.
* @param address The address of the POSIX socket.
* @param length The length of the socket value.
* @return The return code.
* @throws LastErrorException If an error occurs.
*/
int connect(int handle, SocketAddress address, int length) throws LastErrorException;
/**
* Reads from a POSIX socket.
*
* @param handle The socket's handle.
* @param buffer The buffer to read from.
* @param count The bytes being read.
* @return The amount of bytes that could be read.
* @throws LastErrorException If an error occurs.
*/
int read(int handle, ByteBuffer buffer, int count) throws LastErrorException;
/**
* Writes to a POSIX socket.
*
* @param handle The socket's handle.
* @param buffer The buffer to write to.
* @param count The bytes being written.
* @return The return code.
* @throws LastErrorException If an error occurs.
*/
int write(int handle, ByteBuffer buffer, int count) throws LastErrorException;
/**
* Closes the socket connection.
*
* @param handle The handle of the connection.
* @return The return code.
* @throws LastErrorException If an error occurs.
*/
int close(int handle) throws LastErrorException;
/**
* Represents an address for a POSIX socket.
*/
class SocketAddress extends Structure {
/**
* The socket family.
*/
@SuppressWarnings("unused")
@SuppressFBWarnings(value = "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD", justification = "Field required by native implementation.")
public short family = 1;
/**
* The socket path.
*/
public byte[] path = new byte[100];
/**
* Sets the socket path.
*
* @param path The socket path.
*/
protected void setPath(String path) {
try {
System.arraycopy(path.getBytes("UTF-8"), 0, this.path, 0, path.length());
System.arraycopy(new byte[]{0}, 0, this.path, path.length(), 1);
} catch (UnsupportedEncodingException exception) {
throw new IllegalStateException(exception);
}
}
@Override
protected List getFieldOrder() {
return Arrays.asList("family", "path");
}
}
}
/**
* A factory for a POSIX socket connection to a JVM using JNA.
*/
public static class Factory extends Connection.Factory.ForSocketFile {
/**
* The socket library API.
*/
private final PosixLibrary library;
/**
* Creates a connection factory for a POSIX socket using JNA.
*
* @param temporaryDirectory The temporary directory to use.
* @param attempts The maximum amount of attempts for checking the establishment of a socket connection.
* @param pause The pause between two checks for an established socket connection.
* @param timeUnit The time unit of the pause time.
*/
@SuppressWarnings("deprecation")
public Factory(String temporaryDirectory, int attempts, long pause, TimeUnit timeUnit) {
super(temporaryDirectory, attempts, pause, timeUnit);
library = Native.loadLibrary("c", PosixLibrary.class);
}
/**
* Creates a connection factory for a POSIX socket using JNA while locating the default temporary directory used on the
* current platform.
*
* @param attempts The maximum amount of attempts for checking the establishment of a socket connection.
* @param pause The pause between two checks for an established socket connection.
* @param timeUnit The time unit of the pause time.
* @return An appropriate connection factory.
*/
@SuppressWarnings("deprecation")
public static Connection.Factory withDefaultTemporaryFolder(int attempts, long pause, TimeUnit timeUnit) {
String temporaryDirectory;
if (Platform.isMac()) {
MacLibrary library = Native.loadLibrary("c", MacLibrary.class);
Memory memory = new Memory(4096);
try {
long length = library.confstr(MacLibrary.CS_DARWIN_USER_TEMP_DIR, memory, memory.size());
if (length == 0 || length > 4096) {
temporaryDirectory = "/tmp";
} else {
temporaryDirectory = memory.getString(0);
}
} finally {
memory = null;
}
} else {
temporaryDirectory = "/tmp";
}
return new Factory(temporaryDirectory, attempts, pause, timeUnit);
}
@Override
protected void kill(String processId, int signal) {
library.kill(Integer.parseInt(processId), signal);
}
@Override
public Connection doConnect(File socket) {
return new Connection.ForJnaPosixSocket(library, socket);
}
/**
* A library for reading a Mac user's temporary directory.
*/
public interface MacLibrary extends Library {
/**
* The temporary directory.
*/
int CS_DARWIN_USER_TEMP_DIR = 65537;
/**
* Reads a configuration dependant variable into a memory segment.
*
* @param name The name of the variable.
* @param buffer The buffer to read the variable into.
* @param length The length of the buffer.
* @return The amount of bytes written to the buffer.
*/
long confstr(int name, Pointer buffer, long length);
}
}
}
/**
* Implements a connection for a Windows named pipe in JNA.
*/
class ForJnaWindowsNamedPipe implements Connection {
/**
* Indicates a memory release.
*/
private static final int MEM_RELEASE = 0x8000;
/**
* The library to use for communicating with Windows native functions.
*/
private final WindowsLibrary library;
/**
* The library to use for communicating with Windows attachment extension that is included as a DLL.
*/
private final WindowsAttachLibrary attachLibrary;
/**
* The handle of the target VM's process.
*/
private final WinNT.HANDLE process;
/**
* A pointer to the code that was injected into the target process.
*/
private final WinDef.LPVOID code;
/**
* A source of random values being used for generating pipe names.
*/
private final SecureRandom random;
/**
* Creates a new connection via a named pipe.
*
* @param library The library to use for communicating with Windows native functions.
* @param attachLibrary The library to use for communicating with Windows attachment extension that is included as a DLL.
* @param process The handle of the target VM's process.
* @param code A pointer to the code that was injected into the target process.
*/
protected ForJnaWindowsNamedPipe(WindowsLibrary library,
WindowsAttachLibrary attachLibrary,
WinNT.HANDLE process,
WinDef.LPVOID code) {
this.library = library;
this.attachLibrary = attachLibrary;
this.process = process;
this.code = code;
random = new SecureRandom();
}
/**
* {@inheritDoc}
*/
public Response execute(String protocol, String... argument) {
if (!"1".equals(protocol)) {
throw new IllegalArgumentException("Unknown protocol version: " + protocol);
} else if (argument.length > 4) {
throw new IllegalArgumentException("Cannot supply more then four arguments to Windows attach mechanism: " + Arrays.asList(argument));
}
String name = "\\\\.\\pipe\\javatool" + Math.abs(random.nextInt() + 1);
WinNT.HANDLE pipe = Kernel32.INSTANCE.CreateNamedPipe(name,
WinBase.PIPE_ACCESS_INBOUND,
WinBase.PIPE_TYPE_BYTE | WinBase.PIPE_READMODE_BYTE | WinBase.PIPE_WAIT,
1,
4096,
8192,
WinBase.NMPWAIT_USE_DEFAULT_WAIT,
null);
if (pipe == null) {
throw new Win32Exception(Native.getLastError());
}
try {
WinDef.LPVOID data = attachLibrary.allocate_remote_argument(process,
name,
argument.length < 1 ? null : argument[0],
argument.length < 2 ? null : argument[1],
argument.length < 3 ? null : argument[2],
argument.length < 4 ? null : argument[3]);
if (data == null) {
throw new Win32Exception(Native.getLastError());
}
try {
WinNT.HANDLE thread = library.CreateRemoteThread(process, null, 0, code.getPointer(), data.getPointer(), null, null);
if (thread == null) {
throw new Win32Exception(Native.getLastError());
}
try {
int result = Kernel32.INSTANCE.WaitForSingleObject(thread, WinBase.INFINITE);
if (result != 0) {
throw new Win32Exception(result);
}
IntByReference exitCode = new IntByReference();
if (!library.GetExitCodeThread(thread, exitCode)) {
throw new Win32Exception(Native.getLastError());
} else if (exitCode.getValue() != 0) {
throw new IllegalStateException("Target VM could not dispatch command successfully: " + exitCode.getValue());
}
if (!Kernel32.INSTANCE.ConnectNamedPipe(pipe, null)) {
int code = Native.getLastError();
if (code != WinError.ERROR_PIPE_CONNECTED) {
throw new Win32Exception(code);
}
}
return new NamedPipeResponse(pipe);
} finally {
if (!Kernel32.INSTANCE.CloseHandle(thread)) {
throw new Win32Exception(Native.getLastError());
}
}
} finally {
if (!library.VirtualFreeEx(process, data.getPointer(), 0, MEM_RELEASE)) {
throw new Win32Exception(Native.getLastError());
}
}
} catch (Throwable throwable) {
if (!Kernel32.INSTANCE.CloseHandle(pipe)) {
throw new Win32Exception(Native.getLastError());
} else if (throwable instanceof RuntimeException) {
throw (RuntimeException) throwable;
} else {
throw new IllegalStateException(throwable);
}
}
}
/**
* {@inheritDoc}
*/
public void close() {
try {
if (!library.VirtualFreeEx(process, code.getPointer(), 0, MEM_RELEASE)) {
throw new Win32Exception(Native.getLastError());
}
} finally {
if (!Kernel32.INSTANCE.CloseHandle(process)) {
throw new Win32Exception(Native.getLastError());
}
}
}
/**
* A library for interacting with Windows.
*/
protected interface WindowsLibrary extends StdCallLibrary {
/**
* Changes the state of memory in a given process.
*
* @param process The process in which to change the memory.
* @param address The address of the memory to allocate.
* @param size The size of the allocated region.
* @param allocationType The allocation type.
* @param protect The memory protection.
* @return A pointer to the allocated memory.
*/
@SuppressWarnings({"unused", "checkstyle:methodname"})
Pointer VirtualAllocEx(WinNT.HANDLE process, Pointer address, int size, int allocationType, int protect);
/**
* Frees memory in the given process.
*
* @param process The process in which to change the memory.
* @param address The address of the memory to free.
* @param size The size of the freed region.
* @param freeType The freeing type.
* @return {@code true} if the operation succeeded.
*/
@SuppressWarnings("checkstyle:methodname")
boolean VirtualFreeEx(WinNT.HANDLE process, Pointer address, int size, int freeType);
/**
* An alternative implementation of
* {@link Kernel32#CreateRemoteThread(WinNT.HANDLE, WinBase.SECURITY_ATTRIBUTES, int, WinBase.FOREIGN_THREAD_START_ROUTINE, Pointer, WinDef.DWORD, Pointer)}
* that uses a pointer as the {@code code} argument rather then a structure to avoid accessing foreign memory.
*
* @param process A handle of the target process.
* @param securityAttributes The security attributes to use or {@code null} if no attributes are provided.
* @param stackSize The stack size or {@code 0} for using the system default.
* @param code A pointer to the code to execute.
* @param argument A pointer to the argument to provide to the code being executed.
* @param creationFlags The creation flags or {@code null} if no flags are set.
* @param threadId A pointer to the thread id or {@code null} if no thread reference is set.
* @return A handle to the created remote thread or {@code null} if the creation failed.
*/
@MaybeNull
@SuppressWarnings("checkstyle:methodname")
WinNT.HANDLE CreateRemoteThread(WinNT.HANDLE process,
@MaybeNull WinBase.SECURITY_ATTRIBUTES securityAttributes,
int stackSize,
Pointer code,
Pointer argument,
@MaybeNull WinDef.DWORD creationFlags,
@MaybeNull Pointer threadId);
/**
* Receives the exit code of a given thread.
*
* @param thread A handle to the targeted thread.
* @param exitCode A reference to the exit code value.
* @return {@code true} if the exit code retrieval succeeded.
*/
@SuppressWarnings("checkstyle:methodname")
boolean GetExitCodeThread(WinNT.HANDLE thread, IntByReference exitCode);
}
/**
* A library for interacting with Windows.
*/
protected interface WindowsAttachLibrary extends StdCallLibrary {
/**
* Allocates the code to invoke on the remote VM.
*
* @param process A handle to the target process.
* @return A pointer to the allocated code or {@code null} if the code could not be allocated.
*/
@MaybeNull
@SuppressWarnings("checkstyle:methodname")
WinDef.LPVOID allocate_remote_code(WinNT.HANDLE process);
/**
* Allocates the remote argument to supply to the remote code upon execution.
*
* @param process A handle to the target process.
* @param pipe The name of the pipe used for supplying an answer.
* @param argument0 The first argument or {@code null} if no such argument is provided.
* @param argument1 The second argument or {@code null} if no such argument is provided.
* @param argument2 The third argument or {@code null} if no such argument is provided.
* @param argument3 The forth argument or {@code null} if no such argument is provided.
* @return A pointer to the allocated argument or {@code null} if the argument could not be allocated.
*/
@MaybeNull
@SuppressWarnings("checkstyle:methodname")
WinDef.LPVOID allocate_remote_argument(WinNT.HANDLE process,
String pipe,
@MaybeNull String argument0,
@MaybeNull String argument1,
@MaybeNull String argument2,
@MaybeNull String argument3);
}
/**
* A response that is sent via a named pipe.
*/
protected static class NamedPipeResponse implements Response {
/**
* A handle of the named pipe.
*/
private final WinNT.HANDLE pipe;
/**
* Creates a new response via a named pipe.
*
* @param pipe The handle of the named pipe.
*/
protected NamedPipeResponse(WinNT.HANDLE pipe) {
this.pipe = pipe;
}
/**
* {@inheritDoc}
*/
public int read(byte[] buffer) {
IntByReference read = new IntByReference();
if (!Kernel32.INSTANCE.ReadFile(pipe, buffer, buffer.length, read, null)) {
int code = Native.getLastError();
if (code == WinError.ERROR_BROKEN_PIPE) {
return -1;
} else {
throw new Win32Exception(code);
}
}
return read.getValue();
}
/**
* {@inheritDoc}
*/
public void close() {
try {
if (!Kernel32.INSTANCE.DisconnectNamedPipe(pipe)) {
throw new Win32Exception(Native.getLastError());
}
} finally {
if (!Kernel32.INSTANCE.CloseHandle(pipe)) {
throw new Win32Exception(Native.getLastError());
}
}
}
}
/**
* A factory for establishing a connection to a JVM using a named pipe in JNA.
*/
public static class Factory implements Connection.Factory {
/**
* The name of the native code library that is included in this artifact to support Windows attachment.
* This property can be set by other libraries that shade Byte Buddy agent and relocates the library.
*/
public static final String LIBRARY_NAME = "co.elastic.apm.attach.bytebuddy.library.name";
/**
* The library to use for communicating with Windows native functions.
*/
private final WindowsLibrary library;
/**
* The library to use for communicating with Windows attachment extension that is included as a DLL.
*/
private final WindowsAttachLibrary attachLibrary;
/**
* Creates a new connection factory for Windows using JNA.
*/
@SuppressWarnings("deprecation")
public Factory() {
library = Native.loadLibrary("kernel32", WindowsLibrary.class, W32APIOptions.DEFAULT_OPTIONS);
attachLibrary = Native.loadLibrary(System.getProperty(LIBRARY_NAME, "attach_hotspot_windows"), WindowsAttachLibrary.class);
}
/**
* {@inheritDoc}
*/
public Connection connect(String processId) {
WinNT.HANDLE process = Kernel32.INSTANCE.OpenProcess(WinNT.PROCESS_ALL_ACCESS, false, Integer.parseInt(processId));
if (process == null) {
throw new Win32Exception(Native.getLastError());
}
try {
WinDef.LPVOID code = attachLibrary.allocate_remote_code(process);
if (code == null) {
throw new Win32Exception(Native.getLastError());
}
return new ForJnaWindowsNamedPipe(library, attachLibrary, process, code);
} catch (Throwable throwable) {
if (!Kernel32.INSTANCE.CloseHandle(process)) {
throw new Win32Exception(Native.getLastError());
} else if (throwable instanceof RuntimeException) {
throw (RuntimeException) throwable;
} else {
throw new IllegalStateException(throwable);
}
}
}
}
}
/**
* A connection to a VM using a Solaris door.
*/
class ForJnaSolarisDoor implements Connection {
/**
* The library to use for interacting with Solaris.
*/
private final SolarisLibrary library;
/**
* The socket used for communication.
*/
private final File socket;
/**
* Creates a new connection using a Solaris door.
*
* @param library The library to use for interacting with Solaris.
* @param socket The socket used for communication.
*/
protected ForJnaSolarisDoor(SolarisLibrary library, File socket) {
this.library = library;
this.socket = socket;
}
/**
* {@inheritDoc}
*/
@SuppressFBWarnings(value = {"UWF_UNWRITTEN_PUBLIC_OR_PROTECTED_FIELD", "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD"}, justification = "This pattern is required for use of JNA.")
public Connection.Response execute(String protocol, String... argument) throws IOException {
int handle = library.open(socket.getAbsolutePath(), 2);
try {
SolarisLibrary.DoorArgument door = new SolarisLibrary.DoorArgument();
try {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
outputStream.write(protocol.getBytes("UTF-8"));
outputStream.write(0);
for (String anArgument : argument) {
if (anArgument != null) {
outputStream.write(anArgument.getBytes("UTF-8"));
}
outputStream.write(0);
}
door.dataSize = outputStream.size();
Memory dataPointer = new Memory(outputStream.size());
try {
dataPointer.write(0, outputStream.toByteArray(), 0, outputStream.size());
door.dataPointer = dataPointer;
Memory result = new Memory(128);
try {
door.resultPointer = result;
door.resultSize = (int) result.size();
if (library.door_call(handle, door) != 0) {
throw new IllegalStateException("Door call to target VM failed");
} else if (door.resultSize < 4 || door.resultPointer.getInt(0) != 0) {
throw new IllegalStateException("Target VM could not execute door call");
} else if (door.descriptorCount != 1 || door.descriptorPointer == null) {
throw new IllegalStateException("Did not receive communication descriptor from target VM");
} else {
return new Response(library, door.descriptorPointer.getInt(4));
}
} finally {
result = null;
}
} finally {
dataPointer = null;
}
} finally {
door = null;
}
} finally {
library.close(handle);
}
}
/**
* {@inheritDoc}
*/
public void close() {
/* do nothing */
}
/**
* A library for interacting with Solaris.
*/
protected interface SolarisLibrary extends Library {
/**
* Sends a kill signal to the target VM.
*
* @param processId The target process's id.
* @param signal The signal to send.
* @return The return code.
* @throws LastErrorException If an error occurred while sending the signal.
*/
int kill(int processId, int signal) throws LastErrorException;
/**
* Opens a file.
*
* @param file The file name.
* @param flags the flags for opening.
* @return The file descriptor.
* @throws LastErrorException If the file could not be opened.
*/
int open(String file, int flags) throws LastErrorException;
/**
* Reads from a handle.
*
* @param handle The handle representing the source being read.
* @param buffer The buffer to read to.
* @param length The buffer length.
* @return The amount of bytes being read.
* @throws LastErrorException If a read operation failed.
*/
int read(int handle, ByteBuffer buffer, int length) throws LastErrorException;
/**
* Releases a descriptor.
*
* @param descriptor The descriptor to release.
* @return The return code.
* @throws LastErrorException If the descriptor could not be closed.
*/
int close(int descriptor) throws LastErrorException;
/**
* Executes a door call.
*
* @param descriptor The door's descriptor.
* @param argument A pointer to the argument.
* @return The door's handle.
* @throws LastErrorException If the door call failed.
*/
@SuppressWarnings("checkstyle:methodname")
int door_call(int descriptor, DoorArgument argument) throws LastErrorException;
/**
* A structure representing the argument to a Solaris door operation.
*/
class DoorArgument extends Structure {
/**
* A pointer to the operation argument.
*/
@MaybeNull
public Pointer dataPointer;
/**
* The size of the argument being pointed to.
*/
public int dataSize;
/**
* A pointer to the operation descriptor.
*/
@MaybeNull
public Pointer descriptorPointer;
/**
* The size of the operation argument.
*/
public int descriptorCount;
/**
* A pointer to the operation result.
*/
@UnknownNull
public Pointer resultPointer;
/**
* The size of the operation argument.
*/
public int resultSize;
@Override
protected List getFieldOrder() {
return Arrays.asList("dataPointer", "dataSize", "descriptorPointer", "descriptorCount", "resultPointer", "resultSize");
}
}
}
/**
* A response from a VM using a Solaris door.
*/
protected static class Response implements Connection.Response {
/**
* The Solaris library to use.
*/
private final SolarisLibrary library;
/**
* The door handle.
*/
private final int handle;
/**
* Creates a response from a VM using a Solaris door.
*
* @param library The Solaris library to use.
* @param handle The door handle.
*/
protected Response(SolarisLibrary library, int handle) {
this.library = library;
this.handle = handle;
}
/**
* {@inheritDoc}
*/
public int read(byte[] buffer) {
int read = library.read(handle, ByteBuffer.wrap(buffer), buffer.length);
return read == 0 ? -1 : read;
}
/**
* {@inheritDoc}
*/
public void close() {
library.close(handle);
}
}
/**
* A factory for establishing a connection to a JVM using a Solaris door in JNA.
*/
public static class Factory extends Connection.Factory.ForSocketFile {
/**
* The library to use for interacting with Solaris.
*/
private final SolarisLibrary library;
/**
* Creates a new connection factory for a Solaris VM.
*
* @param attempts The maximum amount of attempts for checking the establishment of a socket connection.
* @param pause The pause between two checks for an established socket connection.
* @param timeUnit The time unit of the pause time.
*/
@SuppressWarnings("deprecation")
public Factory(int attempts, long pause, TimeUnit timeUnit) {
super("/tmp", attempts, pause, timeUnit);
library = Native.loadLibrary("c", SolarisLibrary.class);
}
/**
* {@inheritDoc}
*/
protected void kill(String processId, int signal) {
library.kill(Integer.parseInt(processId), signal);
}
/**
* {@inheritDoc}
*/
protected Connection doConnect(File socket) {
return new ForJnaSolarisDoor(library, socket);
}
}
}
}
}
/**
* A virtual machine attachment implementation for OpenJ9 or any compatible JVM.
*/
class ForOpenJ9 extends AbstractBase {
/**
* The temporary folder for attachment files for OpenJ9 VMs.
*/
private static final String IBM_TEMPORARY_FOLDER = "com.ibm.tools.attach.directory";
/**
* The socket on which this VM and the target VM communicate.
*/
private final Socket socket;
/**
* Creates a new virtual machine connection for OpenJ9.
*
* @param socket The socket on which this VM and the target VM communicate.
*/
protected ForOpenJ9(Socket socket) {
this.socket = socket;
}
/**
* Attaches to the supplied process id using the default JNA implementation.
*
* @param processId The process id.
* @return A suitable virtual machine implementation.
* @throws IOException If an IO exception occurs during establishing the connection.
*/
public static VirtualMachine attach(String processId) throws IOException {
return attach(processId, 5000, Platform.isWindows()
? new Dispatcher.ForJnaWindowsEnvironment()
: new Dispatcher.ForJnaPosixEnvironment(15, 100, TimeUnit.MILLISECONDS));
}
/**
* Attaches to the supplied process id.
*
* @param processId The process id.
* @param timeout The timeout for establishing the socket connection.
* @param dispatcher The connector to use to communicate with the target VM.
* @return A suitable virtual machine implementation.
* @throws IOException If an IO exception occurs during establishing the connection.
*/
public static VirtualMachine attach(String processId, int timeout, Dispatcher dispatcher) throws IOException {
File directory = new File(System.getProperty(IBM_TEMPORARY_FOLDER, dispatcher.getTemporaryFolder(processId)), ".com_ibm_tools_attach");
RandomAccessFile attachLock = new RandomAccessFile(new File(directory, "_attachlock"), "rw");
try {
FileLock attachLockLock = attachLock.getChannel().lock();
try {
List virtualMachines;
RandomAccessFile master = new RandomAccessFile(new File(directory, "_master"), "rw");
try {
FileLock masterLock = master.getChannel().lock();
try {
File[] vmFolder = directory.listFiles();
if (vmFolder == null) {
throw new IllegalStateException("No descriptor files found in " + directory);
}
long userId = dispatcher.userId();
virtualMachines = new ArrayList();
for (File aVmFolder : vmFolder) {
if (aVmFolder.isDirectory() && dispatcher.getOwnerIdOf(aVmFolder) == userId) {
File attachInfo = new File(aVmFolder, "attachInfo");
if (attachInfo.isFile()) {
Properties virtualMachine = new Properties();
FileInputStream inputStream = new FileInputStream(attachInfo);
try {
virtualMachine.load(inputStream);
} finally {
inputStream.close();
}
int targetProcessId = Integer.parseInt(virtualMachine.getProperty("processId"));
long targetUserId;
try {
targetUserId = Long.parseLong(virtualMachine.getProperty("userUid"));
} catch (NumberFormatException ignored) {
targetUserId = 0L;
}
if (userId != 0L && targetUserId == 0L) {
targetUserId = dispatcher.getOwnerIdOf(attachInfo);
}
if (targetProcessId == 0L || dispatcher.isExistingProcess(targetProcessId)) {
virtualMachines.add(virtualMachine);
} else if (userId == 0L || targetUserId == userId) {
File[] vmFile = aVmFolder.listFiles();
if (vmFile != null) {
for (File aVmFile : vmFile) {
if (!aVmFile.delete()) {
aVmFile.deleteOnExit();
}
}
}
if (!aVmFolder.delete()) {
aVmFolder.deleteOnExit();
}
}
}
}
}
} finally {
masterLock.release();
}
} finally {
master.close();
}
Properties target = null;
for (Properties virtualMachine : virtualMachines) {
if (virtualMachine.getProperty("processId").equalsIgnoreCase(processId)) {
target = virtualMachine;
break;
}
}
if (target == null) {
throw new IllegalStateException("Could not locate target process info in " + directory);
}
ServerSocket serverSocket = new ServerSocket(0);
try {
serverSocket.setSoTimeout(timeout);
File receiver = new File(directory, target.getProperty("vmId"));
String key = Long.toHexString(new SecureRandom().nextLong());
File reply = new File(receiver, "replyInfo");
try {
if (reply.createNewFile()) {
dispatcher.setPermissions(reply, 0600);
}
FileOutputStream outputStream = new FileOutputStream(reply);
try {
outputStream.write(key.getBytes("UTF-8"));
outputStream.write("\n".getBytes("UTF-8"));
outputStream.write(Long.toString(serverSocket.getLocalPort()).getBytes("UTF-8"));
outputStream.write("\n".getBytes("UTF-8"));
} finally {
outputStream.close();
}
Map locks = new HashMap();
try {
String pid = Long.toString(dispatcher.pid());
for (Properties virtualMachine : virtualMachines) {
if (!virtualMachine.getProperty("processId").equalsIgnoreCase(pid)) {
String attachNotificationSync = virtualMachine.getProperty("attachNotificationSync");
RandomAccessFile syncFile = new RandomAccessFile(attachNotificationSync == null
? new File(directory, "attachNotificationSync")
: new File(attachNotificationSync), "rw");
try {
locks.put(syncFile, syncFile.getChannel().lock());
} catch (IOException ignored) {
syncFile.close();
}
}
}
int notifications = 0;
File[] item = directory.listFiles();
if (item != null) {
for (File anItem : item) {
String name = anItem.getName();
if (!name.startsWith(".trash_")
&& !name.equalsIgnoreCase("_attachlock")
&& !name.equalsIgnoreCase("_master")
&& !name.equalsIgnoreCase("_notifier")) {
notifications += 1;
}
}
}
boolean global = Boolean.parseBoolean(target.getProperty("globalSemaphore"));
dispatcher.incrementSemaphore(directory, "_notifier", global, notifications);
try {
Socket socket = serverSocket.accept();
String answer = new String(read(socket), "UTF-8");
if (answer.contains(' ' + key + ' ')) {
return new ForOpenJ9(socket);
} else {
socket.close();
throw new IllegalStateException("Unexpected answered to attachment: " + answer);
}
} finally {
dispatcher.decrementSemaphore(directory, "_notifier", global, notifications);
}
} finally {
for (Map.Entry entry : locks.entrySet()) {
try {
try {
entry.getValue().release();
} finally {
entry.getKey().close();
}
} catch (Throwable ignored) {
/* do nothing */
}
}
}
} finally {
if (!reply.delete()) {
reply.deleteOnExit();
}
}
} finally {
serverSocket.close();
}
} finally {
attachLockLock.release();
}
} finally {
attachLock.close();
}
}
/**
* {@inheritDoc}
*/
public Properties getSystemProperties() throws IOException {
write(socket, "ATTACH_GETSYSTEMPROPERTIES".getBytes("UTF-8"));
Properties properties = new Properties();
properties.load(new ByteArrayInputStream(read(socket)));
return properties;
}
/**
* {@inheritDoc}
*/
public Properties getAgentProperties() throws IOException {
write(socket, "ATTACH_GETAGENTPROPERTIES".getBytes("UTF-8"));
Properties properties = new Properties();
properties.load(new ByteArrayInputStream(read(socket)));
return properties;
}
/**
* {@inheritDoc}
*/
public void loadAgent(String jarFile, @MaybeNull String argument) throws IOException {
write(socket, ("ATTACH_LOADAGENT(instrument," + jarFile + '=' + (argument == null ? "" : argument) + ')').getBytes("UTF-8"));
String answer = new String(read(socket), "UTF-8");
if (answer.startsWith("ATTACH_ERR")) {
throw new IllegalStateException("Target VM failed loading agent: " + answer);
} else if (!answer.startsWith("ATTACH_ACK") && !answer.startsWith("ATTACH_RESULT=")) {
throw new IllegalStateException("Unexpected response: " + answer);
}
}
/**
* {@inheritDoc}
*/
public void loadAgentPath(String path, @MaybeNull String argument) throws IOException {
write(socket, ("ATTACH_LOADAGENTPATH(" + path + (argument == null ? "" : (',' + argument)) + ')').getBytes("UTF-8"));
String answer = new String(read(socket), "UTF-8");
if (answer.startsWith("ATTACH_ERR")) {
throw new IllegalStateException("Target VM failed loading native agent: " + answer);
} else if (!answer.startsWith("ATTACH_ACK") && !answer.startsWith("ATTACH_RESULT=")) {
throw new IllegalStateException("Unexpected response: " + answer);
}
}
/**
* {@inheritDoc}
*/
public void loadAgentLibrary(String library, @MaybeNull String argument) throws IOException {
write(socket, ("ATTACH_LOADAGENTLIBRARY(" + library + (argument == null ? "" : (',' + argument)) + ')').getBytes("UTF-8"));
String answer = new String(read(socket), "UTF-8");
if (answer.startsWith("ATTACH_ERR")) {
throw new IllegalStateException("Target VM failed loading native library: " + answer);
} else if (!answer.startsWith("ATTACH_ACK") && !answer.startsWith("ATTACH_RESULT=")) {
throw new IllegalStateException("Unexpected response: " + answer);
}
}
/**
* {@inheritDoc}
*/
public void startManagementAgent(Properties properties) throws IOException {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
properties.store(outputStream, null);
write(socket, "ATTACH_START_MANAGEMENT_AGENT".getBytes("UTF-8"));
write(socket, outputStream.toByteArray());
String answer = new String(read(socket), "UTF-8");
if (answer.startsWith("ATTACH_ERR")) {
throw new IllegalStateException("Target VM could not start management agent: " + answer);
} else if (!answer.startsWith("ATTACH_ACK") && !answer.startsWith("ATTACH_RESULT=")) {
throw new IllegalStateException("Unexpected response: " + answer);
}
}
/**
* {@inheritDoc}
*/
public String startLocalManagementAgent() throws IOException {
write(socket, "ATTACH_START_LOCAL_MANAGEMENT_AGENT".getBytes("UTF-8"));
String answer = new String(read(socket), "UTF-8");
if (answer.startsWith("ATTACH_ERR")) {
throw new IllegalStateException("Target VM could not start management agent: " + answer);
} else if (answer.startsWith("ATTACH_ACK")) {
return answer.substring("ATTACH_ACK".length());
} else if (answer.startsWith("ATTACH_RESULT=")) {
return answer.substring("ATTACH_RESULT=".length());
} else {
throw new IllegalStateException("Unexpected response: " + answer);
}
}
/**
* {@inheritDoc}
*/
public void detach() throws IOException {
try {
write(socket, "ATTACH_DETACH".getBytes("UTF-8"));
read(socket); // The answer is intentionally ignored.
} finally {
socket.close();
}
}
/**
* Writes the supplied value to the target socket.
*
* @param socket The socket to write to.
* @param value The value being written.
* @throws IOException If an I/O exception occurs.
*/
private static void write(Socket socket, byte[] value) throws IOException {
socket.getOutputStream().write(value);
socket.getOutputStream().write(0);
socket.getOutputStream().flush();
}
/**
* Reads a {@code '\0'}-terminated value from the target socket.
*
* @param socket The socket to read from.
* @return The value that was read.
* @throws IOException If an I/O exception occurs.
*/
private static byte[] read(Socket socket) throws IOException {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int length;
while ((length = socket.getInputStream().read(buffer)) != -1) {
if (length > 0 && buffer[length - 1] == 0) {
outputStream.write(buffer, 0, length - 1);
break;
} else {
outputStream.write(buffer, 0, length);
}
}
return outputStream.toByteArray();
}
/**
* A dispatcher for native operations being used for communication with an OpenJ9 virtual machine.
*/
public interface Dispatcher {
/**
* Returns this machine's temporary folder.
*
* @param processId The target process's id.
* @return The temporary folder.
*/
String getTemporaryFolder(String processId);
/**
* Returns the process id of this process.
*
* @return The process id of this process.
*/
int pid();
/**
* Returns the user id of this process.
*
* @return The user id of this process
*/
int userId();
/**
* Returns {@code true} if the supplied process id is a running process.
*
* @param processId The process id to evaluate.
* @return {@code true} if the supplied process id is currently running.
*/
boolean isExistingProcess(int processId);
/**
* Returns the user id of the owner of the supplied file.
*
* @param file The file for which to locate the owner.
* @return The owner id of the supplied file.
*/
int getOwnerIdOf(File file);
/**
* Sets permissions for the supplied file.
*
* @param file The file for which to set the permissions.
* @param permissions The permission bits to set.
*/
void setPermissions(File file, int permissions);
/**
* Increments a semaphore.
*
* @param directory The sempahore's control directory.
* @param name The semaphore's name.
* @param global {@code true} if the semaphore is in the global namespace (only applicable on Windows).
* @param count The amount of increments.
*/
void incrementSemaphore(File directory, String name, boolean global, int count);
/**
* Decrements a semaphore.
*
* @param directory The sempahore's control directory.
* @param name The semaphore's name.
* @param global {@code true} if the semaphore is in the global namespace (only applicable on Windows).
* @param count The amount of decrements.
*/
void decrementSemaphore(File directory, String name, boolean global, int count);
/**
* A connector implementation for a POSIX environment using JNA.
*/
class ForJnaPosixEnvironment implements Dispatcher {
/**
* The JNA library to use.
*/
private final PosixLibrary library;
/**
* The maximum amount of attempts for checking the result of a foreign process.
*/
private final int attempts;
/**
* The pause between two checks for another process to return.
*/
private final long pause;
/**
* The time unit of the pause time.
*/
private final TimeUnit timeUnit;
/**
* Creates a new connector for a POSIX enviornment using JNA.
*
* @param attempts The maximum amount of attempts for checking the result of a foreign process.
* @param pause The pause between two checks for another process to return.
* @param timeUnit The time unit of the pause time.
*/
@SuppressWarnings("deprecation")
public ForJnaPosixEnvironment(int attempts, long pause, TimeUnit timeUnit) {
this.attempts = attempts;
this.pause = pause;
this.timeUnit = timeUnit;
library = Native.loadLibrary("c", PosixLibrary.class);
}
/**
* {@inheritDoc}
*/
public String getTemporaryFolder(String processId) {
if (Platform.isLinux()) {
File file = new File("/proc/" + processId + "/root/tmp");
if (file.isDirectory() && file.canRead()) {
return file.getAbsolutePath();
}
}
String temporaryFolder = System.getenv("TMPDIR");
return temporaryFolder == null ? "/tmp" : temporaryFolder;
}
/**
* {@inheritDoc}
*/
public int pid() {
return library.getpid();
}
/**
* {@inheritDoc}
*/
public int userId() {
return library.getuid();
}
/**
* {@inheritDoc}
*/
public boolean isExistingProcess(int processId) {
return library.kill(processId, PosixLibrary.NULL_SIGNAL) != PosixLibrary.ESRCH;
}
/**
* {@inheritDoc}
*/
@SuppressFBWarnings(value = "OS_OPEN_STREAM", justification = "The stream life-cycle is bound to its process.")
public int getOwnerIdOf(File file) {
try {
// The binding for 'stat' is very platform dependant. To avoid the complexity of binding the correct method,
// stat is called as a separate command. This is less efficient but more portable.
Process process = Runtime.getRuntime().exec(new String[]{"stat",
Platform.isMac() ? "-f" : "-c",
"%u",
file.getAbsolutePath()});
int attempts = this.attempts;
boolean exited = false;
String line = new BufferedReader(new InputStreamReader(process.getInputStream(), "UTF-8")).readLine();
do {
try {
if (process.exitValue() != 0) {
throw new IllegalStateException("Error while executing stat");
}
exited = true;
break;
} catch (IllegalThreadStateException ignored) {
try {
Thread.sleep(timeUnit.toMillis(pause));
} catch (InterruptedException exception) {
Thread.currentThread().interrupt();
throw new IllegalStateException(exception);
}
}
} while (--attempts > 0);
if (!exited) {
process.destroy();
throw new IllegalStateException("Command for stat did not exit in time");
}
return Integer.parseInt(line);
} catch (IOException exception) {
throw new IllegalStateException("Unable to execute stat command", exception);
}
}
/**
* {@inheritDoc}
*/
public void setPermissions(File file, int permissions) {
library.chmod(file.getAbsolutePath(), permissions);
}
/**
* {@inheritDoc}
*/
public void incrementSemaphore(File directory, String name, boolean global, int count) {
notifySemaphore(directory, name, count, (short) 1, (short) 0, false);
}
/**
* {@inheritDoc}
*/
public void decrementSemaphore(File directory, String name, boolean global, int count) {
notifySemaphore(directory, name, count, (short) -1, (short) (PosixLibrary.SEM_UNDO | PosixLibrary.IPC_NOWAIT), true);
}
/**
* Notifies a POSIX semaphore.
*
* @param directory The semaphore's directory.
* @param name The semaphore's name.
* @param count The amount of notifications to send.
* @param operation The operation to apply.
* @param flags The flags to set.
* @param acceptUnavailable {@code true} if a {@code EAGAIN} code should be accepted.
*/
@SuppressFBWarnings(value = {"URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD", "UUF_UNUSED_PUBLIC_OR_PROTECTED_FIELD"}, justification = "Modifier is required by JNA.")
private void notifySemaphore(File directory, String name, int count, short operation, short flags, boolean acceptUnavailable) {
int semaphore = library.semget(library.ftok(new File(directory, name).getAbsolutePath(), 0xA1), 2, 0666);
PosixLibrary.SemaphoreOperation target = new PosixLibrary.SemaphoreOperation();
target.operation = operation;
target.flags = flags;
try {
while (count-- > 0) {
try {
library.semop(semaphore, target, 1);
} catch (LastErrorException exception) {
if (acceptUnavailable && (Native.getLastError() == PosixLibrary.EAGAIN
|| Native.getLastError() == PosixLibrary.EDEADLK)) {
break;
} else {
throw exception;
}
}
}
} finally {
target = null;
}
}
/**
* An API for interaction with POSIX systems.
*/
protected interface PosixLibrary extends Library {
/**
* A null signal.
*/
int NULL_SIGNAL = 0;
/**
* Indicates that a process does not exist.
*/
int ESRCH = 3;
/**
* Indicates that a request timed out.
*/
int EAGAIN = 11;
/**
* Indicates a dead lock on a resource.
*/
int EDEADLK = 35;
/**
* Indicates that a semaphore's operations should be undone at process shutdown.
*/
short SEM_UNDO = 0x1000;
/**
* Indicates that one should not wait for the release of a semaphore if it is not currently available.
*/
short IPC_NOWAIT = 04000;
/**
* Runs the {@code getpid} command.
*
* @return The command's return value.
* @throws LastErrorException If an error occurred.
*/
int getpid() throws LastErrorException;
/**
* Runs the {@code getuid} command.
*
* @return The command's return value.
* @throws LastErrorException If an error occurred.
*/
int getuid() throws LastErrorException;
/**
* Runs the {@code kill} command.
*
* @param processId The target process id.
* @param signal The signal to send.
* @return The command's return value.
* @throws LastErrorException If an error occurred.
*/
int kill(int processId, int signal) throws LastErrorException;
/**
* Runs the {@code chmod} command.
*
* @param path The file path.
* @param mode The mode to set.
* @return The return code.
* @throws LastErrorException If an error occurred.
*/
int chmod(String path, int mode) throws LastErrorException;
/**
* Runs the {@code ftok} command.
*
* @param path The file path.
* @param id The id being used for creating the generated key.
* @return The generated key.
* @throws LastErrorException If an error occurred.
*/
int ftok(String path, int id) throws LastErrorException;
/**
* Runs the {@code semget} command.
*
* @param key The key of the semaphore.
* @param count The initial count of the semaphore.
* @param flags The flags to set.
* @return The id of the semaphore.
* @throws LastErrorException If an error occurred.
*/
int semget(int key, int count, int flags) throws LastErrorException;
/**
* Runs the {@code semop} command.
*
* @param id The id of the semaphore.
* @param operation The initial count of the semaphore.
* @param flags The flags to set.
* @return The return code.
* @throws LastErrorException If the operation was not successful.
*/
int semop(int id, SemaphoreOperation operation, int flags) throws LastErrorException;
/**
* A structure to represent a semaphore operation for {@code semop}.
*/
class SemaphoreOperation extends Structure {
/**
* The semaphore number.
*/
@SuppressWarnings("unused")
public short number;
/**
* The operation to execute.
*/
public short operation;
/**
* The flags being set for the operation.
*/
public short flags;
@Override
protected List getFieldOrder() {
return Arrays.asList("number", "operation", "flags");
}
}
}
}
/**
* A connector implementation for a Windows environment using JNA.
*/
class ForJnaWindowsEnvironment implements Dispatcher {
/**
* Indicates a missing user id what is not supported on Windows.
*/
private static final int NO_USER_ID = 0;
/**
* The name of the creation mutex.
*/
private static final String CREATION_MUTEX_NAME = "j9shsemcreationMutex";
/**
* A library to use for interacting with Windows.
*/
private final WindowsLibrary library;
/**
* Creates a new connector for a Windows environment using JNA.
*/
@SuppressWarnings("deprecation")
public ForJnaWindowsEnvironment() {
library = Native.loadLibrary("kernel32", WindowsLibrary.class, W32APIOptions.DEFAULT_OPTIONS);
}
/**
* {@inheritDoc}
*/
public String getTemporaryFolder(String processId) {
WinDef.DWORD length = new WinDef.DWORD(WinDef.MAX_PATH);
char[] path = new char[length.intValue()];
if (Kernel32.INSTANCE.GetTempPath(length, path).intValue() == 0) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
return Native.toString(path);
}
/**
* {@inheritDoc}
*/
public int pid() {
return Kernel32.INSTANCE.GetCurrentProcessId();
}
/**
* {@inheritDoc}
*/
public int userId() {
return NO_USER_ID;
}
/**
* {@inheritDoc}
*/
public boolean isExistingProcess(int processId) {
WinNT.HANDLE handle = Kernel32.INSTANCE.OpenProcess(WinNT.PROCESS_QUERY_INFORMATION, false, processId);
if (handle == null) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
IntByReference exists = new IntByReference();
if (!Kernel32.INSTANCE.GetExitCodeProcess(handle, exists)) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
return exists.getValue() == WinBase.STILL_ACTIVE;
}
/**
* {@inheritDoc}
*/
public int getOwnerIdOf(File file) {
return NO_USER_ID;
}
/**
* {@inheritDoc}
*/
public void setPermissions(File file, int permissions) {
/* do nothing */
}
/**
* {@inheritDoc}
*/
public void incrementSemaphore(File directory, String name, boolean global, int count) {
AttachmentHandle handle = openSemaphore(directory, name, global);
try {
while (count-- > 0) {
if (!library.ReleaseSemaphore(handle.getHandle(), 1, null)) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
}
} finally {
handle.close();
}
}
/**
* {@inheritDoc}
*/
public void decrementSemaphore(File directory, String name, boolean global, int count) {
AttachmentHandle handle = openSemaphore(directory, name, global);
try {
while (count-- > 0) {
int result = Kernel32.INSTANCE.WaitForSingleObject(handle.getHandle(), 0);
switch (result) {
case WinBase.WAIT_ABANDONED:
case WinBase.WAIT_OBJECT_0:
break;
case WinError.WAIT_TIMEOUT:
return;
default:
throw new Win32Exception(result);
}
}
} finally {
handle.close();
}
}
/**
* Opens a semaphore for signaling another process that an attachment is performed.
*
* @param directory The control directory.
* @param name The semaphore's name.
* @param global {@code true} if the semaphore is in the global namespace.
* @return A handle for signaling an attachment to the target process.
*/
private AttachmentHandle openSemaphore(File directory, String name, boolean global) {
WinNT.SECURITY_DESCRIPTOR securityDescriptor = new WinNT.SECURITY_DESCRIPTOR(64 * 1024);
try {
if (!Advapi32.INSTANCE.InitializeSecurityDescriptor(securityDescriptor, WinNT.SECURITY_DESCRIPTOR_REVISION)) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
if (!Advapi32.INSTANCE.SetSecurityDescriptorDacl(securityDescriptor, true, null, true)) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
WindowsLibrary.SecurityAttributes securityAttributes = new WindowsLibrary.SecurityAttributes();
try {
securityAttributes.length = new WinDef.DWORD(securityAttributes.size());
securityAttributes.securityDescriptor = securityDescriptor.getPointer();
WinNT.HANDLE mutex = library.CreateMutex(securityAttributes, false, CREATION_MUTEX_NAME);
if (mutex == null) {
int lastError = Kernel32.INSTANCE.GetLastError();
if (lastError == WinError.ERROR_ALREADY_EXISTS) {
mutex = library.OpenMutex(WinNT.STANDARD_RIGHTS_REQUIRED | WinNT.SYNCHRONIZE | 0x0001, false, CREATION_MUTEX_NAME);
if (mutex == null) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
} else {
throw new Win32Exception(lastError);
}
}
int result = Kernel32.INSTANCE.WaitForSingleObject(mutex, 2000);
switch (result) {
case WinBase.WAIT_FAILED:
case WinError.WAIT_TIMEOUT:
throw new Win32Exception(result);
default:
try {
String target = (global ? "Global\\" : "")
+ (directory.getAbsolutePath() + '_' + name).replaceAll("[^a-zA-Z0-9_]", "")
+ "_semaphore";
WinNT.HANDLE parent = library.OpenSemaphoreW(WindowsLibrary.SEMAPHORE_ALL_ACCESS, false, target);
if (parent == null) {
parent = library.CreateSemaphoreW(null, 0, Integer.MAX_VALUE, target);
if (parent == null) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
WinNT.HANDLE child = library.CreateSemaphoreW(null, 0, Integer.MAX_VALUE, target + "_set0");
if (child == null) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
return new AttachmentHandle(parent, child);
} else {
WinNT.HANDLE child = library.OpenSemaphoreW(WindowsLibrary.SEMAPHORE_ALL_ACCESS, false, target + "_set0");
if (child == null) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
return new AttachmentHandle(parent, child);
}
} finally {
if (!library.ReleaseMutex(mutex)) {
throw new Win32Exception(Native.getLastError());
}
}
}
} finally {
securityAttributes = null;
}
} finally {
securityDescriptor = null;
}
}
/**
* A library for interacting with Windows.
*/
protected interface WindowsLibrary extends StdCallLibrary {
/**
* Indicates that a semaphore requires all access rights.
*/
int SEMAPHORE_ALL_ACCESS = 0x1F0003;
/**
* Opens an existing semaphore.
*
* @param access The access rights.
* @param inheritHandle {@code true} if the handle is inherited.
* @param name The semaphore's name.
* @return The handle or {@code null} if the handle could not be created.
*/
@MaybeNull
@SuppressWarnings("checkstyle:methodname")
WinNT.HANDLE OpenSemaphoreW(int access, boolean inheritHandle, String name);
/**
* Creates a new semaphore.
*
* @param securityAttributes The security attributes for the created semaphore.
* @param count The initial count for the semaphore.
* @param maximumCount The maximum count for the semaphore.
* @param name The semaphore's name.
* @return The handle or {@code null} if the handle could not be created.
*/
@MaybeNull
@SuppressWarnings("checkstyle:methodname")
WinNT.HANDLE CreateSemaphoreW(@MaybeNull WinBase.SECURITY_ATTRIBUTES securityAttributes,
long count,
long maximumCount,
String name);
/**
* Releases the semaphore.
*
* @param handle The semaphore's handle.
* @param count The amount with which to increase the semaphore.
* @param previousCount The previous count of the semaphore or {@code null}.
* @return {@code true} if the semaphore was successfully released.
*/
@SuppressWarnings("checkstyle:methodname")
boolean ReleaseSemaphore(WinNT.HANDLE handle, long count, @MaybeNull Long previousCount);
/**
* Create or opens a mutex.
*
* @param attributes The mutex's security attributes.
* @param owner {@code true} if the caller is supposed to be the initial owner.
* @param name The mutex name.
* @return The handle to the mutex or {@code null} if the mutex could not be created.
*/
@MaybeNull
@SuppressWarnings("checkstyle:methodname")
WinNT.HANDLE CreateMutex(SecurityAttributes attributes, boolean owner, String name);
/**
* Opens an existing object.
*
* @param access The required access privileges.
* @param inherit {@code true} if the mutex should be inherited.
* @param name The mutex's name.
* @return The handle or {@code null} if the mutex could not be opened.
*/
@SuppressWarnings("checkstyle:methodname")
WinNT.HANDLE OpenMutex(int access, boolean inherit, String name);
/**
* Releases the supplied mutex.
*
* @param handle The handle to the mutex.
* @return {@code true} if the handle was successfully released.
*/
@SuppressWarnings("checkstyle:methodname")
boolean ReleaseMutex(WinNT.HANDLE handle);
/**
* A structure representing a mutex's security attributes.
*/
@SuppressFBWarnings(value = {"URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD", "UUF_UNUSED_PUBLIC_OR_PROTECTED_FIELD"}, justification = "Field required by native implementation.")
class SecurityAttributes extends Structure {
/**
* The descriptor's length.
*/
@MaybeNull
public WinDef.DWORD length;
/**
* A pointer to the descriptor.
*/
@MaybeNull
public Pointer securityDescriptor;
/**
* {@code true} if the attributes are inherited.
*/
@SuppressWarnings("unused")
public boolean inherit;
@Override
protected List getFieldOrder() {
return Arrays.asList("length", "securityDescriptor", "inherit");
}
}
}
/**
* A handle for an attachment which is represented by a pair of handles.
*/
protected static class AttachmentHandle implements Closeable {
/**
* The parent handle.
*/
private final WinNT.HANDLE parent;
/**
* The child handle.
*/
private final WinNT.HANDLE child;
/**
* Creates a new attachment handle.
*
* @param parent The parent handle.
* @param child The child handle.
*/
protected AttachmentHandle(WinNT.HANDLE parent, WinNT.HANDLE child) {
this.parent = parent;
this.child = child;
}
/**
* Returns the handle on which signals are to be sent.
*
* @return The handle on which signals are to be sent.
*/
protected WinNT.HANDLE getHandle() {
return child;
}
/**
* {@inheritDoc}
*/
public void close() {
boolean closed;
try {
if (!Kernel32.INSTANCE.CloseHandle(child)) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
} finally {
closed = Kernel32.INSTANCE.CloseHandle(parent);
}
if (!closed) {
throw new Win32Exception(Kernel32.INSTANCE.GetLastError());
}
}
}
}
}
}
}
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