/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.hadoop.util;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.HashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.Arrays;
import java.util.LinkedList;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.util.Shell.ExitCodeException;
import org.apache.hadoop.util.Shell.ShellCommandExecutor;
/**
* A Proc file-system based ProcessTree. Works only on Linux.
*/
public class ProcfsBasedProcessTree {
private static final Log LOG = LogFactory
.getLog("org.apache.hadoop.mapred.ProcfsBasedProcessTree");
private static final String PROCFS = "/proc/";
public static final long DEFAULT_SLEEPTIME_BEFORE_SIGKILL = 5000L;
private long sleepTimeBeforeSigKill = DEFAULT_SLEEPTIME_BEFORE_SIGKILL;
private static final Pattern PROCFS_STAT_FILE_FORMAT = Pattern
.compile("^([0-9-]+)\\s([^\\s]+)\\s[^\\s]\\s([0-9-]+)\\s([0-9-]+)\\s([0-9-]+)\\s([0-9-]+\\s){16}([0-9]+)(\\s[0-9-]+){16}");
// to enable testing, using this variable which can be configured
// to a test directory.
private String procfsDir;
private Integer pid = -1;
private Map<Integer, ProcessInfo> processTree = new HashMap<Integer, ProcessInfo>();
public ProcfsBasedProcessTree(String pid) {
this(pid, PROCFS);
}
public ProcfsBasedProcessTree(String pid, String procfsDir) {
this.pid = getValidPID(pid);
this.procfsDir = procfsDir;
}
public void setSigKillInterval(long interval) {
sleepTimeBeforeSigKill = interval;
}
/**
* Checks if the ProcfsBasedProcessTree is available on this system.
*
* @return true if ProcfsBasedProcessTree is available. False otherwise.
*/
public static boolean isAvailable() {
try {
String osName = System.getProperty("os.name");
if (!osName.startsWith("Linux")) {
LOG.info("ProcfsBasedProcessTree currently is supported only on "
+ "Linux.");
return false;
}
} catch (SecurityException se) {
LOG.warn("Failed to get Operating System name. " + se);
return false;
}
return true;
}
/**
* Get the process-tree with latest state. If the root-process is not alive,
* an empty tree will be returned.
*
* @return the process-tree with latest state.
*/
public ProcfsBasedProcessTree getProcessTree() {
if (pid != -1) {
// Get the list of processes
List<Integer> processList = getProcessList();
Map<Integer, ProcessInfo> allProcessInfo = new HashMap<Integer, ProcessInfo>();
// cache the processTree to get the age for processes
Map<Integer, ProcessInfo> oldProcs =
new HashMap<Integer, ProcessInfo>(processTree);
processTree.clear();
ProcessInfo me = null;
for (Integer proc : processList) {
// Get information for each process
ProcessInfo pInfo = new ProcessInfo(proc);
if (constructProcessInfo(pInfo, procfsDir) != null) {
allProcessInfo.put(proc, pInfo);
if (proc.equals(this.pid)) {
me = pInfo; // cache 'me'
processTree.put(proc, pInfo);
}
}
}
if (me == null) {
return this;
}
// Add each process to its parent.
for (Map.Entry<Integer, ProcessInfo> entry : allProcessInfo.entrySet()) {
Integer pID = entry.getKey();
if (pID != 1) {
ProcessInfo pInfo = entry.getValue();
ProcessInfo parentPInfo = allProcessInfo.get(pInfo.getPpid());
if (parentPInfo != null) {
parentPInfo.addChild(pInfo);
}
}
}
// now start constructing the process-tree
LinkedList<ProcessInfo> pInfoQueue = new LinkedList<ProcessInfo>();
pInfoQueue.addAll(me.getChildren());
while (!pInfoQueue.isEmpty()) {
ProcessInfo pInfo = pInfoQueue.remove();
if (!processTree.containsKey(pInfo.getPid())) {
processTree.put(pInfo.getPid(), pInfo);
}
pInfoQueue.addAll(pInfo.getChildren());
}
// update age values.
for (Map.Entry<Integer, ProcessInfo> procs : processTree.entrySet()) {
ProcessInfo oldInfo = oldProcs.get(procs.getKey());
if (oldInfo != null) {
if (procs.getValue() != null) {
procs.getValue().updateAge(oldInfo);
}
}
}
if (LOG.isDebugEnabled()) {
// Log.debug the ProcfsBasedProcessTree
LOG.debug(this.toString());
}
}
return this;
}
/**
* Is the process-tree alive? Currently we care only about the status of the
* root-process.
*
* @return true if the process-true is alive, false otherwise.
*/
public boolean isAlive() {
if (pid == -1) {
return false;
} else {
return this.isAlive(pid);
}
}
/**
* Destroy the process-tree. Currently we only make sure the root process is
* gone. It is the responsibility of the root process to make sure that all
* its descendants are cleaned up.
*/
public void destroy() {
LOG.debug("Killing ProcfsBasedProcessTree of " + pid);
if (pid == -1) {
return;
}
ShellCommandExecutor shexec = null;
if (isAlive(this.pid)) {
try {
String[] args = { "kill", this.pid.toString() };
shexec = new ShellCommandExecutor(args);
shexec.execute();
} catch (IOException ioe) {
LOG.warn("Error executing shell command " + ioe);
} finally {
LOG.info("Killing " + pid + " with SIGTERM. Exit code "
+ shexec.getExitCode());
}
}
SigKillThread sigKillThread = new SigKillThread();
sigKillThread.setDaemon(true);
sigKillThread.start();
}
/**
* Get the cumulative virtual memory used by all the processes in the
* process-tree.
*
* @return cumulative virtual memory used by the process-tree in bytes.
*/
public long getCumulativeVmem() {
// include all processes.. all processes will be older than 0.
return getCumulativeVmem(0);
}
/**
* Get the cumulative virtual memory used by all the processes in the
* process-tree that are older than the passed in age.
*
* @param olderThanAge processes above this age are included in the
* memory addition
* @return cumulative virtual memory used by the process-tree in bytes,
* for processes older than this age.
*/
public long getCumulativeVmem(int olderThanAge) {
long total = 0;
for (ProcessInfo p : processTree.values()) {
if ((p != null) && (p.getAge() > olderThanAge)) {
total += p.getVmem();
}
}
return total;
}
/**
* Get PID from a pid-file.
*
* @param pidFileName
* Name of the pid-file.
* @return the PID string read from the pid-file. Returns null if the
* pidFileName points to a non-existing file or if read fails from the
* file.
*/
public static String getPidFromPidFile(String pidFileName) {
BufferedReader pidFile = null;
FileReader fReader = null;
String pid = null;
try {
fReader = new FileReader(pidFileName);
pidFile = new BufferedReader(fReader);
} catch (FileNotFoundException f) {
LOG.debug("PidFile doesn't exist : " + pidFileName);
return pid;
}
try {
pid = pidFile.readLine();
} catch (IOException i) {
LOG.error("Failed to read from " + pidFileName);
} finally {
try {
if (fReader != null) {
fReader.close();
}
try {
if (pidFile != null) {
pidFile.close();
}
} catch (IOException i) {
LOG.warn("Error closing the stream " + pidFile);
}
} catch (IOException i) {
LOG.warn("Error closing the stream " + fReader);
}
}
return pid;
}
private Integer getValidPID(String pid) {
Integer retPid = -1;
try {
retPid = Integer.parseInt((String) pid);
if (retPid <= 0) {
retPid = -1;
}
} catch (NumberFormatException nfe) {
retPid = -1;
}
return retPid;
}
/**
* Get the list of all processes in the system.
*/
private List<Integer> getProcessList() {
String[] processDirs = (new File(procfsDir)).list();
List<Integer> processList = new ArrayList<Integer>();
for (String dir : processDirs) {
try {
int pd = Integer.parseInt(dir);
if ((new File(procfsDir, dir)).isDirectory()) {
processList.add(Integer.valueOf(pd));
}
} catch (NumberFormatException n) {
// skip this directory
} catch (SecurityException s) {
// skip this process
}
}
return processList;
}
/**
*
* Construct the ProcessInfo using the process' PID and procfs and return the
* same. Returns null on failing to read from procfs,
*/
private ProcessInfo constructProcessInfo(ProcessInfo pinfo) {
return constructProcessInfo(pinfo, PROCFS);
}
/**
* Construct the ProcessInfo using the process' PID and procfs rooted at the
* specified directory and return the same. It is provided mainly to assist
* testing purposes.
*
* Returns null on failing to read from procfs,
*
* @param pinfo ProcessInfo that needs to be updated
* @param procfsDir root of the proc file system
* @return updated ProcessInfo, null on errors.
*/
private ProcessInfo constructProcessInfo(ProcessInfo pinfo,
String procfsDir) {
ProcessInfo ret = null;
// Read "procfsDir/<pid>/stat" file
BufferedReader in = null;
FileReader fReader = null;
try {
File pidDir = new File(procfsDir, String.valueOf(pinfo.getPid()));
fReader = new FileReader(new File(pidDir, "/stat"));
in = new BufferedReader(fReader);
} catch (FileNotFoundException f) {
// The process vanished in the interim!
return ret;
}
ret = pinfo;
try {
String str = in.readLine(); // only one line
Matcher m = PROCFS_STAT_FILE_FORMAT.matcher(str);
boolean mat = m.find();
if (mat) {
// Set ( name ) ( ppid ) ( pgrpId ) (session ) (vsize )
pinfo.updateProcessInfo(m.group(2), Integer.parseInt(m.group(3)), Integer
.parseInt(m.group(4)), Integer.parseInt(m.group(5)), Long
.parseLong(m.group(7)));
}
} catch (IOException io) {
LOG.warn("Error reading the stream " + io);
ret = null;
} finally {
// Close the streams
try {
if (fReader != null) {
fReader.close();
}
try {
if (in != null) {
in.close();
}
} catch (IOException i) {
LOG.warn("Error closing the stream " + in);
}
} catch (IOException i) {
LOG.warn("Error closing the stream " + fReader);
}
}
return ret;
}
/**
* Is the process with PID pid still alive?
*/
private boolean isAlive(Integer pid) {
// This method assumes that isAlive is called on a pid that was alive not
// too long ago, and hence assumes no chance of pid-wrapping-around.
ShellCommandExecutor shexec = null;
try {
String[] args = { "kill", "-0", pid.toString() };
shexec = new ShellCommandExecutor(args);
shexec.execute();
} catch (ExitCodeException ee) {
return false;
} catch (IOException ioe) {
LOG.warn("Error executing shell command "
+ Arrays.toString(shexec.getExecString()) + ioe);
return false;
}
return (shexec.getExitCode() == 0 ? true : false);
}
/**
* Helper thread class that kills process-tree with SIGKILL in background
*/
private class SigKillThread extends Thread {
public void run() {
this.setName(this.getClass().getName() + "-" + String.valueOf(pid));
ShellCommandExecutor shexec = null;
try {
// Sleep for some time before sending SIGKILL
Thread.sleep(sleepTimeBeforeSigKill);
} catch (InterruptedException i) {
LOG.warn("Thread sleep is interrupted.");
}
// Kill the root process with SIGKILL if it is still alive
if (ProcfsBasedProcessTree.this.isAlive(pid)) {
try {
String[] args = { "kill", "-9", pid.toString() };
shexec = new ShellCommandExecutor(args);
shexec.execute();
} catch (IOException ioe) {
LOG.warn("Error executing shell command " + ioe);
} finally {
LOG.info("Killing " + pid + " with SIGKILL. Exit code "
+ shexec.getExitCode());
}
}
}
}
/**
* Returns a string printing PIDs of process present in the
* ProcfsBasedProcessTree. Output format : [pid pid ..]
*/
public String toString() {
StringBuffer pTree = new StringBuffer("[ ");
for (Integer p : processTree.keySet()) {
pTree.append(p);
pTree.append(" ");
}
return pTree.substring(0, pTree.length()) + "]";
}
/**
*
* Class containing information of a process.
*
*/
private static class ProcessInfo {
private Integer pid; // process-id
private String name; // command name
private Integer pgrpId; // process group-id
private Integer ppid; // parent process-id
private Integer sessionId; // session-id
private Long vmem; // virtual memory usage
// how many times has this process been seen alive
private int age;
private List<ProcessInfo> children = new ArrayList<ProcessInfo>(); // list of children
public ProcessInfo(int pid) {
this.pid = Integer.valueOf(pid);
// seeing this the first time.
this.age = 1;
}
public Integer getPid() {
return pid;
}
public String getName() {
return name;
}
public Integer getPgrpId() {
return pgrpId;
}
public Integer getPpid() {
return ppid;
}
public Integer getSessionId() {
return sessionId;
}
public Long getVmem() {
return vmem;
}
public int getAge() {
return age;
}
public boolean isParent(ProcessInfo p) {
if (pid.equals(p.getPpid())) {
return true;
}
return false;
}
public void updateProcessInfo(String name, Integer ppid, Integer pgrpId,
Integer sessionId, Long vmem) {
this.name = name;
this.ppid = ppid;
this.pgrpId = pgrpId;
this.sessionId = sessionId;
this.vmem = vmem;
}
public void updateAge(ProcessInfo oldInfo) {
this.age = oldInfo.age + 1;
}
public boolean addChild(ProcessInfo p) {
return children.add(p);
}
public List<ProcessInfo> getChildren() {
return children;
}
}
}