/**
* 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 extends ProcessTree {
static final Log LOG = LogFactory
.getLog(ProcfsBasedProcessTree.class);
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}");
static final String PROCFS_STAT_FILE = "stat";
static final String PROCFS_CMDLINE_FILE = "cmdline";
// to enable testing, using this variable which can be configured
// to a test directory.
private String procfsDir;
private Integer pid = -1;
private boolean setsidUsed = false;
private long sleeptimeBeforeSigkill = DEFAULT_SLEEPTIME_BEFORE_SIGKILL;
private Map<Integer, ProcessInfo> processTree = new HashMap<Integer, ProcessInfo>();
public ProcfsBasedProcessTree(String pid) {
this(pid, false, DEFAULT_SLEEPTIME_BEFORE_SIGKILL);
}
public ProcfsBasedProcessTree(String pid, boolean setsidUsed,
long sigkillInterval) {
this(pid,PROCFS);
this.setsidUsed = setsidUsed;
sleeptimeBeforeSigkill = sigkillInterval;
}
public ProcfsBasedProcessTree(String pid, String procfsDir) {
this.pid = getValidPID(pid);
this.procfsDir = procfsDir;
}
/**
* Sets SIGKILL interval
* @deprecated Use {@link ProcfsBasedProcessTree#ProcfsBasedProcessTree(
* String, boolean, long)} instead
* @param interval The time to wait before sending SIGKILL
* after sending SIGTERM
*/
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 root-process alive?
*
* @return true if the root-process is alive, false otherwise.
*/
public boolean isAlive() {
if (pid == -1) {
return false;
} else {
return isAlive(pid.toString());
}
}
/**
* Is any of the subprocesses in the process-tree alive?
*
* @return true if any of the processes in the process-tree is
* alive, false otherwise.
*/
public boolean isAnyProcessInTreeAlive() {
for (Integer pId : processTree.keySet()) {
if (isAlive(pId.toString())) {
return true;
}
}
return false;
}
/** Verify that the given process id is same as its process group id.
* @param pidStr Process id of the to-be-verified-process
*/
private static boolean assertPidPgrpidForMatch(String pidStr) {
Integer pId = Integer.parseInt(pidStr);
// Get information for this process
ProcessInfo pInfo = new ProcessInfo(pId);
pInfo = constructProcessInfo(pInfo);
//make sure that pId and its pgrpId match
if (!pInfo.getPgrpId().equals(pId)) {
LOG.warn("Unexpected: Process with PID " + pId +
" is not a process group leader.");
return false;
}
if (LOG.isDebugEnabled()) {
LOG.debug(pId + " is a process group leader, as expected.");
}
return true;
}
/** Make sure that the given pid is a process group leader and then
* destroy the process group.
* @param pgrpId Process group id of to-be-killed-processes
* @param interval The time to wait before sending SIGKILL
* after sending SIGTERM
* @param inBackground Process is to be killed in the back ground with
* a separate thread
*/
public static void assertAndDestroyProcessGroup(String pgrpId, long interval,
boolean inBackground)
throws IOException {
// Make sure that the pid given is a process group leader
if (!assertPidPgrpidForMatch(pgrpId)) {
throw new IOException("Process with PID " + pgrpId +
" is not a process group leader.");
}
destroyProcessGroup(pgrpId, interval, inBackground);
}
/**
* Destroy the process-tree.
*/
public void destroy() {
destroy(true);
}
/**
* Destroy the process-tree.
* @param inBackground Process is to be killed in the back ground with
* a separate thread
*/
public void destroy(boolean inBackground) {
LOG.debug("Killing ProcfsBasedProcessTree of " + pid);
if (pid == -1) {
return;
}
if (isAlive(pid.toString())) {
if (isSetsidAvailable && setsidUsed) {
// In this case, we know that pid got created using setsid. So kill the
// whole processGroup.
try {
assertAndDestroyProcessGroup(pid.toString(), sleeptimeBeforeSigkill,
inBackground);
} catch (IOException e) {
LOG.warn(StringUtils.stringifyException(e));
}
}
else {
//TODO: Destroy all the processes in the subtree in this case also.
// For the time being, killing only the root process.
destroyProcess(pid.toString(), sleeptimeBeforeSigkill, inBackground);
}
}
}
private static final String PROCESSTREE_DUMP_FORMAT =
"\t|- %d %d %d %d %s %d %s\n";
/**
* Get a dump of the process-tree.
*
* @return a string concatenating the dump of information of all the processes
* in the process-tree
*/
public String getProcessTreeDump() {
StringBuilder ret = new StringBuilder();
// The header.
ret.append(String.format("\t|- PID PPID PGRPID SESSID CMD_NAME "
+ "VMEM_USAGE(BYTES) FULL_CMD_LINE\n"));
for (ProcessInfo p : processTree.values()) {
if (p != null) {
ret.append(String.format(PROCESSTREE_DUMP_FORMAT, p.getPid(), p
.getPpid(), p.getPgrpId(), p.getSessionId(), p.getName(), p
.getVmem(), p.getCmdLine(procfsDir)));
}
}
return ret.toString();
}
/**
* 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;
}
private static 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 static 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 static 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, PROCFS_STAT_FILE));
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 {
fReader.close();
try {
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;
}
public String getCmdLine(String procfsDir) {
String ret = "N/A";
if (pid == null) {
return ret;
}
BufferedReader in = null;
FileReader fReader = null;
try {
fReader =
new FileReader(new File(new File(procfsDir, pid.toString()),
PROCFS_CMDLINE_FILE));
} catch (FileNotFoundException f) {
// The process vanished in the interim!
return ret;
}
in = new BufferedReader(fReader);
try {
ret = in.readLine(); // only one line
ret = ret.replace('\0', ' '); // Replace each null char with a space
if (ret.equals("")) {
// The cmdline might be empty because the process is swapped out or is
// a zombie.
ret = "N/A";
}
} catch (IOException io) {
LOG.warn("Error reading the stream " + io);
ret = "N/A";
} finally {
// Close the streams
try {
fReader.close();
try {
in.close();
} catch (IOException i) {
LOG.warn("Error closing the stream " + in);
}
} catch (IOException i) {
LOG.warn("Error closing the stream " + fReader);
}
}
return ret;
}
}
}