/*
* Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* 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
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.tools.jstack;
import java.lang.reflect.Method;
import java.lang.reflect.Constructor;
import java.io.IOException;
import java.io.InputStream;
import com.sun.tools.attach.VirtualMachine;
import com.sun.tools.attach.AttachNotSupportedException;
import sun.tools.attach.HotSpotVirtualMachine;
/*
* This class is the main class for the JStack utility. It parses its arguments
* and decides if the command should be executed by the SA JStack tool or by
* obtained the thread dump from a target process using the VM attach mechanism
*/
public class JStack {
public static void main(String[] args) throws Exception {
if (args.length == 0) {
usage(); // no arguments
}
boolean useSA = false;
boolean mixed = false;
boolean locks = false;
// Parse the options (arguments starting with "-" )
int optionCount = 0;
while (optionCount < args.length) {
String arg = args[optionCount];
if (!arg.startsWith("-")) {
break;
}
if (arg.equals("-F")) {
useSA = true;
} else {
if (arg.equals("-m")) {
mixed = true;
} else {
if (arg.equals("-l")) {
locks = true;
} else {
usage();
}
}
}
optionCount++;
}
// mixed stack implies SA tool
if (mixed) {
useSA = true;
}
// Next we check the parameter count. If there are two parameters
// we assume core file and executable so we use SA.
int paramCount = args.length - optionCount;
if (paramCount == 0 || paramCount > 2) {
usage();
}
if (paramCount == 2) {
useSA = true;
} else {
// If we can't parse it as a pid then it must be debug server
if (!args[optionCount].matches("[0-9]+")) {
useSA = true;
}
}
// now execute using the SA JStack tool or the built-in thread dumper
if (useSA) {
// parameters (<pid> or <exe> <core>
String params[] = new String[paramCount];
for (int i=optionCount; i<args.length; i++ ){
params[i-optionCount] = args[i];
}
runJStackTool(mixed, locks, params);
} else {
// pass -l to thread dump operation to get extra lock info
String pid = args[optionCount];
String params[];
if (locks) {
params = new String[] { "-l" };
} else {
params = new String[0];
}
runThreadDump(pid, params);
}
}
// SA JStack tool
private static void runJStackTool(boolean mixed, boolean locks, String args[]) throws Exception {
Class<?> cl = loadSAClass();
if (cl == null) {
usage(); // SA not available
}
// JStack tool also takes -m and -l arguments
if (mixed) {
args = prepend("-m", args);
}
if (locks) {
args = prepend("-l", args);
}
Class[] argTypes = { String[].class };
Method m = cl.getDeclaredMethod("main", argTypes);
Object[] invokeArgs = { args };
m.invoke(null, invokeArgs);
}
// Returns sun.jvm.hotspot.tools.JStack if available, otherwise null.
private static Class<?> loadSAClass() {
//
// Attempt to load JStack class - we specify the system class
// loader so as to cater for development environments where
// this class is on the boot class path but sa-jdi.jar is on
// the system class path. Once the JDK is deployed then both
// tools.jar and sa-jdi.jar are on the system class path.
//
try {
return Class.forName("sun.jvm.hotspot.tools.JStack", true,
ClassLoader.getSystemClassLoader());
} catch (Exception x) { }
return null;
}
// Attach to pid and perform a thread dump
private static void runThreadDump(String pid, String args[]) throws Exception {
VirtualMachine vm = null;
try {
vm = VirtualMachine.attach(pid);
} catch (Exception x) {
String msg = x.getMessage();
if (msg != null) {
System.err.println(pid + ": " + msg);
} else {
x.printStackTrace();
}
if ((x instanceof AttachNotSupportedException) &&
(loadSAClass() != null)) {
System.err.println("The -F option can be used when the target " +
"process is not responding");
}
System.exit(1);
}
// Cast to HotSpotVirtualMachine as this is implementation specific
// method.
InputStream in = ((HotSpotVirtualMachine)vm).remoteDataDump((Object[])args);
// read to EOF and just print output
byte b[] = new byte[256];
int n;
do {
n = in.read(b);
if (n > 0) {
String s = new String(b, 0, n, "UTF-8");
System.out.print(s);
}
} while (n > 0);
in.close();
vm.detach();
}
// return a new string array with arg as the first element
private static String[] prepend(String arg, String args[]) {
String[] newargs = new String[args.length+1];
newargs[0] = arg;
System.arraycopy(args, 0, newargs, 1, args.length);
return newargs;
}
// print usage message
private static void usage() {
System.out.println("Usage:");
System.out.println(" jstack [-l] <pid>");
System.out.println(" (to connect to running process)");
if (loadSAClass() != null) {
System.out.println(" jstack -F [-m] [-l] <pid>");
System.out.println(" (to connect to a hung process)");
System.out.println(" jstack [-m] [-l] <executable> <core>");
System.out.println(" (to connect to a core file)");
System.out.println(" jstack [-m] [-l] [server_id@]<remote server IP or hostname>");
System.out.println(" (to connect to a remote debug server)");
}
System.out.println("");
System.out.println("Options:");
if (loadSAClass() != null) {
System.out.println(" -F to force a thread dump. Use when jstack <pid> does not respond" +
" (process is hung)");
System.out.println(" -m to print both java and native frames (mixed mode)");
}
System.out.println(" -l long listing. Prints additional information about locks");
System.out.println(" -h or -help to print this help message");
System.exit(1);
}
}