src/jdk.internal.jvmstat/linux/classes/sun/jvmstat/PlatformSupportImpl.java - platform/libcore - Git at Google

 /*
  * 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;
         }
     }
 }
	/*
	* 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;
	}
	}
	}