There is an old reported problem that using jmap on a process that is
not running
Java could cause the process to terminate. This is due to the SIGQUIT used
when attaching to the process.
It is a fairly simple operation to validate that the pid matches one of
the known
running Java processes using VirtualMachine.list().
Issue: https://bugs.openjdk.java.net/browse/JDK-8149461
Proposed fix:
diff --git a/src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java
b/src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java
--- a/src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java
+++ b/src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights
reserved.
+ * Copyright (c) 2005, 2019, 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
@@ -30,6 +30,7 @@
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.Collection;
+import java.util.List;
import com.sun.tools.attach.VirtualMachine;
import com.sun.tools.attach.VirtualMachineDescriptor;
@@ -125,6 +126,10 @@
private static void executeCommandForPid(String pid, String
command, Object ... args)
throws AttachNotSupportedException, IOException,
UnsupportedEncodingException {
+ // Before attaching, confirm that pid is a known Java process
+ if (!checkJavaPid(pid)) {
+ throw new AttachNotSupportedException();
+ }
VirtualMachine vm = VirtualMachine.attach(pid);
// Cast to HotSpotVirtualMachine as this is an
@@ -196,6 +201,19 @@
executeCommandForPid(pid, "dumpheap", filename, liveopt);
}
+ // Check that pid matches a known running Java process
+ static boolean checkJavaPid(String pid) {
+ List<VirtualMachineDescriptor> l = VirtualMachine.list();
+ boolean found = false;
+ for (VirtualMachineDescriptor vmd: l) {
+ if (vmd.id().equals(pid)) {
+ found = true;
+ break;
+ }
+ }
+ return found;
+ }
+
private static void checkForUnsupportedOptions(String[] args) {
// Check arguments for -F, -m, and non-numeric value
// and warn the user that SA is not supported anymore
