--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.internal.jvmstat/linux/classes/sun/jvmstat/PlatformSupportImpl.java Mon Jan 22 15:05:03 2018 -0500
@@ -0,0 +1,227 @@
+/*
+ * Copyright (c) 2018, 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
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package sun.jvmstat;
+
+import java.io.*;
+import java.util.*;
+import java.util.regex.*;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.Files;
+import java.nio.charset.*;
+
+/*
+ * Linux specific implementation of the PlatformSupport routines
+ * providing process ID and temp directory support for host and
+ * cgroup container processes.
+ */
+public class PlatformSupportImpl extends PlatformSupport {
+ private static final String containerTmpPath = "/root" + getTemporaryDirectory();
+ private static final String pidPatternStr = "^[0-9]+$";
+
+ /*
+ * Return the temporary directories that the VM uses for the attach
+ * and perf data files. This function returns the traditional
+ * /tmp directory in addition to paths within the /proc file system
+ * allowing access to container tmp directories such as /proc/{pid}/root/tmp.
+ *
+ * It is important that this directory is well-known and the
+ * same for all VM instances. It cannot be affected by configuration
+ * variables such as java.io.tmpdir.
+ *
+ * Implementation Details:
+ *
+ * Java processes that run in docker containers are typically running
+ * under cgroups with separate pid namespaces which means that pids
+ * within the container are different that the pid which is visible
+ * from the host. The container pids typically start with 1 and
+ * increase. The java process running in the container will use these
+ * pids when creating the hsperfdata files. In order to locate java
+ * processes that are running in containers, we take advantage of
+ * the Linux proc file system which maps the containers tmp directory
+ * to the hosts under /proc/{hostpid}/root/tmp. We use the /proc status
+ * file /proc/{hostpid}/status to determine the containers pid and
+ * then access the hsperfdata file. The status file contains an
+ * entry "NSPid:" which shows the mapping from the hostpid to the
+ * containers pid.
+ *
+ * Example:
+ *
+ * NSPid: 24345 11
+ *
+ * In this example process 24345 is visible from the host,
+ * is running under the PID namespace and has a container specific
+ * pid of 11.
+ *
+ * The search for Java processes is done by first looking in the
+ * traditional /tmp for host process hsperfdata files and then
+ * the search will container in every /proc/{pid}/root/tmp directory.
+ * There are of course added complications to this search that
+ * need to be taken into account.
+ *
+ * 1. duplication of tmp directories
+ *
+ * /proc/{hostpid}/root/tmp directories exist for many processes
+ * that are running on a Linux kernel that has cgroups enabled even
+ * if they are not running in a container. To avoid this duplication,
+ * we compare the inode of the /proc tmp directories to /tmp and
+ * skip these duplicated directories.
+ *
+ * 2. Containerized processes without PID namespaces being enabled.
+ *
+ * If a container is running a Java process without namespaces being
+ * enabled, an hsperfdata file will only be located at
+ * /proc/{hostpid}/root/tmp/{hostpid}. This is handled by
+ * checking the last component in the path for both the hostpid
+ * and potential namespacepids (if one exists).
+ */
+ public List<String> getTemporaryDirectories(int pid) {
+ FilenameFilter pidFilter;
+ Matcher pidMatcher;
+ Pattern pidPattern = Pattern.compile(pidPatternStr);
+ long tmpInode = 0;
+
+ File procdir = new File("/proc");
+
+ if (pid != 0) {
+ pidPattern = Pattern.compile(Integer.toString(pid));
+ }
+ else {
+ pidPattern = Pattern.compile(pidPatternStr);
+ }
+ pidMatcher = pidPattern.matcher("");
+
+ // Add the default temporary directory first
+ List<String> v = new ArrayList<>();
+ v.add(getTemporaryDirectory());
+
+ try {
+ File f = new File(getTemporaryDirectory());
+ tmpInode = (Long)Files.getAttribute(f.toPath(), "unix:ino");
+ }
+ catch (IOException e) {}
+
+ pidFilter = new FilenameFilter() {
+ public boolean accept(File dir, String name) {
+ if (!dir.isDirectory())
+ return false;
+ pidMatcher.reset(name);
+ return pidMatcher.matches();
+ }
+ };
+
+ File[] dirs = procdir.listFiles(pidFilter);
+
+ // Add all unique /proc/{pid}/root/tmp dirs that are not mapped to /tmp
+ for (File dir : dirs) {
+ String containerTmpDir = dir.getAbsolutePath() + containerTmpPath;
+ File containerFile = new File(containerTmpDir);
+
+ try {
+ long procInode = (Long)Files.getAttribute(containerFile.toPath(), "unix:ino");
+ if (containerFile.exists() && containerFile.isDirectory() &&
+ containerFile.canRead() && procInode != tmpInode) {
+ v.add(containerTmpDir);
+ }
+ }
+ catch (IOException e) {}
+ }
+
+ return v;
+ }
+
+
+ /*
+ * Extract either the host PID or the NameSpace PID
+ * from a file path.
+ *
+ * File path should be in 1 of these 2 forms:
+ *
+ * /proc/{pid}/root/tmp/hsperfdata_{user}/{nspid}
+ * or
+ * /tmp/hsperfdata_{user}/{pid}
+ *
+ * In either case we want to return {pid} and NOT {nspid}
+ *
+ * This function filters out host pids which do not have
+ * associated hsperfdata files. This is due to the fact that
+ * getTemporaryDirectories will return /proc/{pid}/root/tmp
+ * paths for all container processes whether they are java
+ * processes or not causing duplicate matches.
+ */
+ public int getLocalVmId(File file) throws NumberFormatException {
+ String p = file.getAbsolutePath();
+ String s[] = p.split("\\/");
+
+ // Determine if this file is from a container
+ if (s.length == 7 && s[1].equals("proc")) {
+ int hostpid = Integer.parseInt(s[2]);
+ int nspid = Integer.parseInt(s[6]);
+ if (nspid == hostpid || nspid == getNamespaceVmId(hostpid)) {
+ return hostpid;
+ }
+ else {
+ return -1;
+ }
+ }
+ else {
+ return Integer.parseInt(file.getName());
+ }
+ }
+
+
+ /*
+ * Return the inner most namespaced PID if there is one,
+ * otherwise return the original PID.
+ */
+ public int getNamespaceVmId(int pid) {
+ // Assuming a real procfs sits beneath, reading this doesn't block
+ // nor will it consume a lot of memory.
+ Path statusPath = Paths.get("/proc", Integer.toString(pid), "status");
+ if (Files.notExists(statusPath)) {
+ return pid; // Likely a bad pid, but this is properly handled later.
+ }
+
+ try {
+ for (String line : Files.readAllLines(statusPath, StandardCharsets.UTF_8)) {
+ String[] parts = line.split(":");
+ if (parts.length == 2 && parts[0].trim().equals("NSpid")) {
+ parts = parts[1].trim().split("\\s+");
+ // The last entry represents the PID the JVM "thinks" it is.
+ // Even in non-namespaced pids these entries should be
+ // valid. You could refer to it as the inner most pid.
+ int ns_pid = Integer.parseInt(parts[parts.length - 1]);
+ return ns_pid;
+ }
+ }
+ // Old kernels may not have NSpid field (i.e. 3.10).
+ // Fallback to original pid in the event we cannot deduce.
+ return pid;
+ } catch (NumberFormatException | IOException x) {
+ return pid;
+ }
+ }
+}