ojluni/src/main/java/java/lang/UNIXProcess.java - platform/libcore - Git at Google

 /*
  * Copyright (C) 2014 The Android Open Source Project
  * Copyright (c) 1995, 2010, 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 java.lang;

 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.ByteArrayInputStream;
 import java.io.FileDescriptor;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.Arrays;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ThreadFactory;
 import java.security.AccessController;
 import static java.security.AccessController.doPrivileged;
 import java.security.PrivilegedAction;
 import java.security.PrivilegedActionException;
 import java.security.PrivilegedExceptionAction;

 /**
  * java.lang.Process subclass in the UNIX environment.
  *
  * @author Mario Wolczko and Ross Knippel.
  * @author Konstantin Kladko (ported to Linux)
  * @author Martin Buchholz
  */
 final class UNIXProcess extends Process {
     private final int pid;
     private int exitcode;
     private boolean hasExited;

     private /* final */ OutputStream stdin;
     private /* final */ InputStream  stdout;
     private /* final */ InputStream  stderr;

     /* this is for the reaping thread */
     private native int waitForProcessExit(int pid);

     /**
      * Create a process using fork(2) and exec(2).
      *
      * @param fds an array of three file descriptors.
      *        Indexes 0, 1, and 2 correspond to standard input,
      *        standard output and standard error, respectively.  On
      *        input, a value of -1 means to create a pipe to connect
      *        child and parent processes.  On output, a value which
      *        is not -1 is the parent pipe fd corresponding to the
      *        pipe which has been created.  An element of this array
      *        is -1 on input if and only if it is <em>not</em> -1 on
      *        output.
      * @return the pid of the subprocess
      */
     private native int forkAndExec(byte[] prog,
                                    byte[] argBlock, int argc,
                                    byte[] envBlock, int envc,
                                    byte[] dir,
                                    int[] fds,
                                    boolean redirectErrorStream)
         throws IOException;

     /**
      * The thread factory used to create "process reaper" daemon threads.
      */
     private static class ProcessReaperThreadFactory implements ThreadFactory {
         private final static ThreadGroup group = getRootThreadGroup();

         private static ThreadGroup getRootThreadGroup() {
             return doPrivileged(new PrivilegedAction<ThreadGroup> () {
                 public ThreadGroup run() {
                     ThreadGroup root = Thread.currentThread().getThreadGroup();
                     while (root.getParent() != null)
                         root = root.getParent();
                     return root;
                 }});
         }

         public Thread newThread(Runnable grimReaper) {
             // Our thread stack requirement is quite modest.
             Thread t = new Thread(group, grimReaper, "process reaper", 32768);
             t.setDaemon(true);
             // A small attempt (probably futile) to avoid priority inversion
             t.setPriority(Thread.MAX_PRIORITY);
             return t;
         }
     }

     /**
      * The thread pool of "process reaper" daemon threads.
      */
     private static final Executor processReaperExecutor =
         doPrivileged(new PrivilegedAction<Executor>() {
             public Executor run() {
                 return Executors.newCachedThreadPool
                     (new ProcessReaperThreadFactory());
             }});

     UNIXProcess(final byte[] prog,
                 final byte[] argBlock, final int argc,
                 final byte[] envBlock, final int envc,
                 final byte[] dir,
                 final int[] fds,
                 final boolean redirectErrorStream)
             throws IOException {

         pid = forkAndExec(prog,
                           argBlock, argc,
                           envBlock, envc,
                           dir,
                           fds,
                           redirectErrorStream);

         try {
             doPrivileged(new PrivilegedExceptionAction<Void>() {
                 public Void run() throws IOException {
                     initStreams(fds);
                     return null;
                 }});
         } catch (PrivilegedActionException ex) {
             throw (IOException) ex.getException();
         }
     }

     static FileDescriptor newFileDescriptor(int fd) {
         FileDescriptor fileDescriptor = new FileDescriptor();
         fileDescriptor.setInt$(fd);
         return fileDescriptor;
     }

     void initStreams(int[] fds) throws IOException {
         stdin = (fds[0] == -1) ?
             ProcessBuilder.NullOutputStream.INSTANCE :
             new ProcessPipeOutputStream(fds[0]);

         stdout = (fds[1] == -1) ?
             ProcessBuilder.NullInputStream.INSTANCE :
             new ProcessPipeInputStream(fds[1]);

         stderr = (fds[2] == -1) ?
             ProcessBuilder.NullInputStream.INSTANCE :
             new ProcessPipeInputStream(fds[2]);

         processReaperExecutor.execute(new Runnable() {
             public void run() {
                 int exitcode = waitForProcessExit(pid);
                 UNIXProcess.this.processExited(exitcode);
             }});
     }

     void processExited(int exitcode) {
         synchronized (this) {
             this.exitcode = exitcode;
             hasExited = true;
             notifyAll();
         }

         if (stdout instanceof ProcessPipeInputStream)
             ((ProcessPipeInputStream) stdout).processExited();

         if (stderr instanceof ProcessPipeInputStream)
             ((ProcessPipeInputStream) stderr).processExited();

         if (stdin instanceof ProcessPipeOutputStream)
             ((ProcessPipeOutputStream) stdin).processExited();
     }

     public OutputStream getOutputStream() {
         return stdin;
     }

     public InputStream getInputStream() {
         return stdout;
     }

     public InputStream getErrorStream() {
         return stderr;
     }

     public synchronized int waitFor() throws InterruptedException {
         while (!hasExited) {
             wait();
         }
         return exitcode;
     }

     public synchronized int exitValue() {
         if (!hasExited) {
             throw new IllegalThreadStateException("process hasn't exited");
         }
         return exitcode;
     }

     private static native void destroyProcess(int pid);
     public void destroy() {
         // There is a risk that pid will be recycled, causing us to
         // kill the wrong process!  So we only terminate processes
         // that appear to still be running.  Even with this check,
         // there is an unavoidable race condition here, but the window
         // is very small, and OSes try hard to not recycle pids too
         // soon, so this is quite safe.
         synchronized (this) {
             if (!hasExited)
                 destroyProcess(pid);
         }
         try { stdin.close();  } catch (IOException ignored) {}
         try { stdout.close(); } catch (IOException ignored) {}
         try { stderr.close(); } catch (IOException ignored) {}
     }

     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder("Process[pid=");
         sb.append(pid);
         if (hasExited) {
             sb.append(" ,hasExited=true, exitcode=");
             sb.append(exitcode);
             sb.append("]");
         } else {
             sb.append(", hasExited=false]");
         }

         return sb.toString();
     }

     /* This routine initializes JNI field offsets for the class */
     private static native void initIDs();

     static {
         initIDs();
     }

     /**
      * A buffered input stream for a subprocess pipe file descriptor
      * that allows the underlying file descriptor to be reclaimed when
      * the process exits, via the processExited hook.
      *
      * This is tricky because we do not want the user-level InputStream to be
      * closed until the user invokes close(), and we need to continue to be
      * able to read any buffered data lingering in the OS pipe buffer.
      */
     static class ProcessPipeInputStream extends BufferedInputStream {
         ProcessPipeInputStream(int fd) {
             super(new FileInputStream(newFileDescriptor(fd), true /* isFdOwner */));
         }

         private static byte[] drainInputStream(InputStream in)
                 throws IOException {
             if (in == null) return null;
             int n = 0;
             int j;
             byte[] a = null;
             while ((j = in.available()) > 0) {
                 a = (a == null) ? new byte[j] : Arrays.copyOf(a, n + j);
                 n += in.read(a, n, j);
             }
             return (a == null || n == a.length) ? a : Arrays.copyOf(a, n);
         }

         /** Called by the process reaper thread when the process exits. */
         synchronized void processExited() {
             // Most BufferedInputStream methods are synchronized, but close()
             // is not, and so we have to handle concurrent racing close().
             try {
                 InputStream in = this.in;
                 if (in != null) {
                     byte[] stragglers = drainInputStream(in);
                     in.close();
                     this.in = (stragglers == null) ?
                         ProcessBuilder.NullInputStream.INSTANCE :
                         new ByteArrayInputStream(stragglers);
                     if (buf == null) // asynchronous close()?
                         this.in = null;
                 }
             } catch (IOException ignored) {
                 // probably an asynchronous close().
             }
         }
     }

     /**
      * A buffered output stream for a subprocess pipe file descriptor
      * that allows the underlying file descriptor to be reclaimed when
      * the process exits, via the processExited hook.
      */
     static class ProcessPipeOutputStream extends BufferedOutputStream {
         ProcessPipeOutputStream(int fd) {
             super(new FileOutputStream(newFileDescriptor(fd), true /* isFdOwner */));
         }

         /** Called by the process reaper thread when the process exits. */
         synchronized void processExited() {
             OutputStream out = this.out;
             if (out != null) {
                 try {
                     out.close();
                 } catch (IOException ignored) {
                     // We know of no reason to get an IOException, but if
                     // we do, there's nothing else to do but carry on.
                 }
                 this.out = ProcessBuilder.NullOutputStream.INSTANCE;
             }
         }
     }
 }
	/*
	* Copyright (C) 2014 The Android Open Source Project
	* Copyright (c) 1995, 2010, 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 java.lang;

	import java.io.BufferedInputStream;
	import java.io.BufferedOutputStream;
	import java.io.ByteArrayInputStream;
	import java.io.FileDescriptor;
	import java.io.FileInputStream;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStream;
	import java.io.OutputStream;
	import java.util.Arrays;
	import java.util.concurrent.Executors;
	import java.util.concurrent.Executor;
	import java.util.concurrent.ThreadFactory;
	import java.security.AccessController;
	import static java.security.AccessController.doPrivileged;
	import java.security.PrivilegedAction;
	import java.security.PrivilegedActionException;
	import java.security.PrivilegedExceptionAction;

	/**
	* java.lang.Process subclass in the UNIX environment.
	*
	* @author Mario Wolczko and Ross Knippel.
	* @author Konstantin Kladko (ported to Linux)
	* @author Martin Buchholz
	*/
	final class UNIXProcess extends Process {
	private final int pid;
	private int exitcode;
	private boolean hasExited;

	private /* final */ OutputStream stdin;
	private /* final */ InputStream stdout;
	private /* final */ InputStream stderr;

	/* this is for the reaping thread */
	private native int waitForProcessExit(int pid);

	/**
	* Create a process using fork(2) and exec(2).
	*
	* @param fds an array of three file descriptors.
	* Indexes 0, 1, and 2 correspond to standard input,
	* standard output and standard error, respectively. On
	* input, a value of -1 means to create a pipe to connect
	* child and parent processes. On output, a value which
	* is not -1 is the parent pipe fd corresponding to the
	* pipe which has been created. An element of this array
	* is -1 on input if and only if it is <em>not</em> -1 on
	* output.
	* @return the pid of the subprocess
	*/
	private native int forkAndExec(byte[] prog,
	byte[] argBlock, int argc,
	byte[] envBlock, int envc,
	byte[] dir,
	int[] fds,
	boolean redirectErrorStream)
	throws IOException;

	/**
	* The thread factory used to create "process reaper" daemon threads.
	*/
	private static class ProcessReaperThreadFactory implements ThreadFactory {
	private final static ThreadGroup group = getRootThreadGroup();

	private static ThreadGroup getRootThreadGroup() {
	return doPrivileged(new PrivilegedAction<ThreadGroup> () {
	public ThreadGroup run() {
	ThreadGroup root = Thread.currentThread().getThreadGroup();
	while (root.getParent() != null)
	root = root.getParent();
	return root;
	}});
	}

	public Thread newThread(Runnable grimReaper) {
	// Our thread stack requirement is quite modest.
	Thread t = new Thread(group, grimReaper, "process reaper", 32768);
	t.setDaemon(true);
	// A small attempt (probably futile) to avoid priority inversion
	t.setPriority(Thread.MAX_PRIORITY);
	return t;
	}
	}

	/**
	* The thread pool of "process reaper" daemon threads.
	*/
	private static final Executor processReaperExecutor =
	doPrivileged(new PrivilegedAction<Executor>() {
	public Executor run() {
	return Executors.newCachedThreadPool
	(new ProcessReaperThreadFactory());
	}});

	UNIXProcess(final byte[] prog,
	final byte[] argBlock, final int argc,
	final byte[] envBlock, final int envc,
	final byte[] dir,
	final int[] fds,
	final boolean redirectErrorStream)
	throws IOException {

	pid = forkAndExec(prog,
	argBlock, argc,
	envBlock, envc,
	dir,
	fds,
	redirectErrorStream);

	try {
	doPrivileged(new PrivilegedExceptionAction<Void>() {
	public Void run() throws IOException {
	initStreams(fds);
	return null;
	}});
	} catch (PrivilegedActionException ex) {
	throw (IOException) ex.getException();
	}
	}

	static FileDescriptor newFileDescriptor(int fd) {
	FileDescriptor fileDescriptor = new FileDescriptor();
	fileDescriptor.setInt$(fd);
	return fileDescriptor;
	}

	void initStreams(int[] fds) throws IOException {
	stdin = (fds[0] == -1) ?
	ProcessBuilder.NullOutputStream.INSTANCE :
	new ProcessPipeOutputStream(fds[0]);

	stdout = (fds[1] == -1) ?
	ProcessBuilder.NullInputStream.INSTANCE :
	new ProcessPipeInputStream(fds[1]);

	stderr = (fds[2] == -1) ?
	ProcessBuilder.NullInputStream.INSTANCE :
	new ProcessPipeInputStream(fds[2]);

	processReaperExecutor.execute(new Runnable() {
	public void run() {
	int exitcode = waitForProcessExit(pid);
	UNIXProcess.this.processExited(exitcode);
	}});
	}

	void processExited(int exitcode) {
	synchronized (this) {
	this.exitcode = exitcode;
	hasExited = true;
	notifyAll();
	}

	if (stdout instanceof ProcessPipeInputStream)
	((ProcessPipeInputStream) stdout).processExited();

	if (stderr instanceof ProcessPipeInputStream)
	((ProcessPipeInputStream) stderr).processExited();

	if (stdin instanceof ProcessPipeOutputStream)
	((ProcessPipeOutputStream) stdin).processExited();
	}

	public OutputStream getOutputStream() {
	return stdin;
	}

	public InputStream getInputStream() {
	return stdout;
	}

	public InputStream getErrorStream() {
	return stderr;
	}

	public synchronized int waitFor() throws InterruptedException {
	while (!hasExited) {
	wait();
	}
	return exitcode;
	}

	public synchronized int exitValue() {
	if (!hasExited) {
	throw new IllegalThreadStateException("process hasn't exited");
	}
	return exitcode;
	}

	private static native void destroyProcess(int pid);
	public void destroy() {
	// There is a risk that pid will be recycled, causing us to
	// kill the wrong process! So we only terminate processes
	// that appear to still be running. Even with this check,
	// there is an unavoidable race condition here, but the window
	// is very small, and OSes try hard to not recycle pids too
	// soon, so this is quite safe.
	synchronized (this) {
	if (!hasExited)
	destroyProcess(pid);
	}
	try { stdin.close(); } catch (IOException ignored) {}
	try { stdout.close(); } catch (IOException ignored) {}
	try { stderr.close(); } catch (IOException ignored) {}
	}

	@Override
	public String toString() {
	StringBuilder sb = new StringBuilder("Process[pid=");
	sb.append(pid);
	if (hasExited) {
	sb.append(" ,hasExited=true, exitcode=");
	sb.append(exitcode);
	sb.append("]");
	} else {
	sb.append(", hasExited=false]");
	}

	return sb.toString();
	}

	/* This routine initializes JNI field offsets for the class */
	private static native void initIDs();

	static {
	initIDs();
	}

	/**
	* A buffered input stream for a subprocess pipe file descriptor
	* that allows the underlying file descriptor to be reclaimed when
	* the process exits, via the processExited hook.
	*
	* This is tricky because we do not want the user-level InputStream to be
	* closed until the user invokes close(), and we need to continue to be
	* able to read any buffered data lingering in the OS pipe buffer.
	*/
	static class ProcessPipeInputStream extends BufferedInputStream {
	ProcessPipeInputStream(int fd) {
	super(new FileInputStream(newFileDescriptor(fd), true /* isFdOwner */));
	}

	private static byte[] drainInputStream(InputStream in)
	throws IOException {
	if (in == null) return null;
	int n = 0;
	int j;
	byte[] a = null;
	while ((j = in.available()) > 0) {
	a = (a == null) ? new byte[j] : Arrays.copyOf(a, n + j);
	n += in.read(a, n, j);
	}
	return (a == null \|\| n == a.length) ? a : Arrays.copyOf(a, n);
	}

	/** Called by the process reaper thread when the process exits. */
	synchronized void processExited() {
	// Most BufferedInputStream methods are synchronized, but close()
	// is not, and so we have to handle concurrent racing close().
	try {
	InputStream in = this.in;
	if (in != null) {
	byte[] stragglers = drainInputStream(in);
	in.close();
	this.in = (stragglers == null) ?
	ProcessBuilder.NullInputStream.INSTANCE :
	new ByteArrayInputStream(stragglers);
	if (buf == null) // asynchronous close()?
	this.in = null;
	}
	} catch (IOException ignored) {
	// probably an asynchronous close().
	}
	}
	}

	/**
	* A buffered output stream for a subprocess pipe file descriptor
	* that allows the underlying file descriptor to be reclaimed when
	* the process exits, via the processExited hook.
	*/
	static class ProcessPipeOutputStream extends BufferedOutputStream {
	ProcessPipeOutputStream(int fd) {
	super(new FileOutputStream(newFileDescriptor(fd), true /* isFdOwner */));
	}

	/** Called by the process reaper thread when the process exits. */
	synchronized void processExited() {
	OutputStream out = this.out;
	if (out != null) {
	try {
	out.close();
	} catch (IOException ignored) {
	// We know of no reason to get an IOException, but if
	// we do, there's nothing else to do but carry on.
	}
	this.out = ProcessBuilder.NullOutputStream.INSTANCE;
	}
	}
	}
	}