src/solaris/classes/java/lang/UNIXProcess.java
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@@ -1,7 +1,7 @@
/*
- * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1995, 2014, 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
@@ -33,10 +33,13 @@
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
+import java.util.EnumSet;
+import java.util.Locale;
+import java.util.Set;
import java.util.concurrent.Executors;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.security.AccessController;
@@ -47,12 +50,13 @@
/**
* java.lang.Process subclass in the UNIX environment.
*
* @author Mario Wolczko and Ross Knippel.
- * @author Konstantin Kladko (ported to Linux)
+ * @author Konstantin Kladko (ported to Linux and Bsd)
* @author Martin Buchholz
+ * @author Volker Simonis (ported to AIX)
*/
final class UNIXProcess extends Process {
private static final sun.misc.JavaIOFileDescriptorAccess fdAccess
= sun.misc.SharedSecrets.getJavaIOFileDescriptorAccess();
@@ -62,21 +66,110 @@
private /* final */ OutputStream stdin;
private /* final */ InputStream stdout;
private /* final */ InputStream stderr;
+ // only used on Solaris
+ private /* final */ DeferredCloseInputStream stdout_inner_stream;
+
private static enum LaunchMechanism {
- FORK(1),
- VFORK(3);
+ // order IS important!
+ FORK,
+ POSIX_SPAWN,
+ VFORK
+ }
- private int value;
- LaunchMechanism(int x) {value = x;}
- };
+ private static enum Platform {
+
+ LINUX(LaunchMechanism.VFORK, LaunchMechanism.FORK),
+
+ BSD(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK),
+
+ SOLARIS(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK),
+
+ AIX(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK);
+
+ final LaunchMechanism defaultLaunchMechanism;
+ final Set<LaunchMechanism> validLaunchMechanisms;
+
+ Platform(LaunchMechanism ... launchMechanisms) {
+ this.defaultLaunchMechanism = launchMechanisms[0];
+ this.validLaunchMechanisms =
+ EnumSet.copyOf(Arrays.asList(launchMechanisms));
+ }
+
+ private String helperPath(String javahome, String osArch) {
+ switch (this) {
+ case SOLARIS:
+ if (osArch.equals("x86")) { osArch = "i386"; }
+ else if (osArch.equals("x86_64")) { osArch = "amd64"; }
+ // fall through...
+ case LINUX:
+ case AIX:
+ return javahome + "/lib/" + osArch + "/jspawnhelper";
+
+ case BSD:
+ return javahome + "/lib/jspawnhelper";
+
+ default:
+ throw new AssertionError("Unsupported platform: " + this);
+ }
+ }
+
+ String helperPath() {
+ return AccessController.doPrivileged(
+ (PrivilegedAction<String>) () ->
+ helperPath(System.getProperty("java.home"),
+ System.getProperty("os.arch"))
+ );
+ }
+
+ LaunchMechanism launchMechanism() {
+ return AccessController.doPrivileged(
+ (PrivilegedAction<LaunchMechanism>) () -> {
+ String s = System.getProperty(
+ "jdk.lang.Process.launchMechanism");
+ LaunchMechanism lm;
+ if (s == null) {
+ lm = defaultLaunchMechanism;
+ s = lm.name().toLowerCase(Locale.ENGLISH);
+ } else {
+ try {
+ lm = LaunchMechanism.valueOf(
+ s.toUpperCase(Locale.ENGLISH));
+ } catch (IllegalArgumentException e) {
+ lm = null;
+ }
+ }
+ if (lm == null || !validLaunchMechanisms.contains(lm)) {
+ throw new Error(
+ s + " is not a supported " +
+ "process launch mechanism on this platform."
+ );
+ }
+ return lm;
+ }
+ );
+ }
+
+ static Platform get() {
+ String osName = AccessController.doPrivileged(
+ (PrivilegedAction<String>) () -> System.getProperty("os.name")
+ );
+
+ if (osName.equals("Linux")) { return LINUX; }
+ if (osName.contains("OS X")) { return BSD; }
+ if (osName.equals("SunOS")) { return SOLARIS; }
+ if (osName.equals("AIX")) { return AIX; }
+
+ throw new Error(osName + " is not a supported OS platform.");
+ }
+ }
- /* default is VFORK on Linux */
- private static final LaunchMechanism launchMechanism;
- private static byte[] helperpath;
+ private static final Platform platform = Platform.get();
+ private static final LaunchMechanism launchMechanism = platform.launchMechanism();
+ private static final byte[] helperpath = toCString(platform.helperPath());
private static byte[] toCString(String s) {
if (s == null)
return null;
byte[] bytes = s.getBytes();
@@ -86,32 +179,10 @@
bytes.length);
result[result.length-1] = (byte)0;
return result;
}
- static {
- launchMechanism = AccessController.doPrivileged(
- new PrivilegedAction<LaunchMechanism>()
- {
- public LaunchMechanism run() {
- String javahome = System.getProperty("java.home");
- String osArch = System.getProperty("os.arch");
-
- helperpath = toCString(javahome + "/lib/" + osArch + "/jspawnhelper");
- String s = System.getProperty(
- "jdk.lang.Process.launchMechanism", "vfork");
-
- try {
- return LaunchMechanism.valueOf(s.toUpperCase());
- } catch (IllegalArgumentException e) {
- throw new Error(s + " is not a supported " +
- "process launch mechanism on this platform.");
- }
- }
- });
- }
-
/* this is for the reaping thread */
private native int waitForProcessExit(int pid);
/**
* Create a process. Depending on the mode flag, this is done by
@@ -139,68 +210,54 @@
int[] fds,
boolean redirectErrorStream)
throws IOException;
/**
- * The thread factory used to create "process reaper" daemon threads.
+ * The thread pool of "process reaper" daemon threads.
*/
- private static class ProcessReaperThreadFactory implements ThreadFactory {
- private final static ThreadGroup group = getRootThreadGroup();
+ private static final Executor processReaperExecutor =
+ doPrivileged((PrivilegedAction<Executor>) () -> {
- 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;
- }});
- }
+ ThreadGroup tg = Thread.currentThread().getThreadGroup();
+ while (tg.getParent() != null) tg = tg.getParent();
+ ThreadGroup systemThreadGroup = tg;
- public Thread newThread(Runnable grimReaper) {
+ ThreadFactory threadFactory = grimReaper -> {
// Our thread stack requirement is quite modest.
- Thread t = new Thread(group, grimReaper, "process reaper", 32768);
+ Thread t = new Thread(systemThreadGroup, 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());
- }});
+ return Executors.newCachedThreadPool(threadFactory);
+ });
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(launchMechanism.value,
+ pid = forkAndExec(launchMechanism.ordinal() + 1,
helperpath,
prog,
argBlock, argc,
envBlock, envc,
dir,
fds,
redirectErrorStream);
try {
- doPrivileged(new PrivilegedExceptionAction<Void>() {
- public Void run() throws IOException {
+ doPrivileged((PrivilegedExceptionAction<Void>) () -> {
initStreams(fds);
return null;
- }});
+ });
} catch (PrivilegedActionException ex) {
throw (IOException) ex.getException();
}
}
@@ -209,10 +266,13 @@
fdAccess.set(fileDescriptor, fd);
return fileDescriptor;
}
void initStreams(int[] fds) throws IOException {
+ switch (platform) {
+ case LINUX:
+ case BSD:
stdin = (fds[0] == -1) ?
ProcessBuilder.NullOutputStream.INSTANCE :
new ProcessPipeOutputStream(fds[0]);
stdout = (fds[1] == -1) ?
@@ -221,32 +281,101 @@
stderr = (fds[2] == -1) ?
ProcessBuilder.NullInputStream.INSTANCE :
new ProcessPipeInputStream(fds[2]);
- processReaperExecutor.execute(new Runnable() {
- public void run() {
+ processReaperExecutor.execute(() -> {
int exitcode = waitForProcessExit(pid);
- UNIXProcess.this.processExited(exitcode);
- }});
- }
- void processExited(int exitcode) {
synchronized (this) {
this.exitcode = exitcode;
- hasExited = true;
- notifyAll();
+ this.hasExited = true;
+ this.notifyAll();
}
if (stdout instanceof ProcessPipeInputStream)
((ProcessPipeInputStream) stdout).processExited();
if (stderr instanceof ProcessPipeInputStream)
((ProcessPipeInputStream) stderr).processExited();
if (stdin instanceof ProcessPipeOutputStream)
((ProcessPipeOutputStream) stdin).processExited();
+ });
+ break;
+
+ case SOLARIS:
+ stdin = (fds[0] == -1) ?
+ ProcessBuilder.NullOutputStream.INSTANCE :
+ new BufferedOutputStream(
+ new FileOutputStream(newFileDescriptor(fds[0])));
+
+ stdout = (fds[1] == -1) ?
+ ProcessBuilder.NullInputStream.INSTANCE :
+ new BufferedInputStream(
+ stdout_inner_stream =
+ new DeferredCloseInputStream(
+ newFileDescriptor(fds[1])));
+
+ stderr = (fds[2] == -1) ?
+ ProcessBuilder.NullInputStream.INSTANCE :
+ new DeferredCloseInputStream(newFileDescriptor(fds[2]));
+
+ /*
+ * For each subprocess forked a corresponding reaper task
+ * is submitted. That task is the only thread which waits
+ * for the subprocess to terminate and it doesn't hold any
+ * locks while doing so. This design allows waitFor() and
+ * exitStatus() to be safely executed in parallel (and they
+ * need no native code).
+ */
+ processReaperExecutor.execute(() -> {
+ int exitcode = waitForProcessExit(pid);
+
+ synchronized (this) {
+ this.exitcode = exitcode;
+ this.hasExited = true;
+ this.notifyAll();
+ }
+ });
+ break;
+
+ case AIX:
+ stdin = (fds[0] == -1) ?
+ ProcessBuilder.NullOutputStream.INSTANCE :
+ new ProcessPipeOutputStream(fds[0]);
+
+ stdout = (fds[1] == -1) ?
+ ProcessBuilder.NullInputStream.INSTANCE :
+ new DeferredCloseProcessPipeInputStream(fds[1]);
+
+ stderr = (fds[2] == -1) ?
+ ProcessBuilder.NullInputStream.INSTANCE :
+ new DeferredCloseProcessPipeInputStream(fds[2]);
+
+ processReaperExecutor.execute(() -> {
+ int exitcode = waitForProcessExit(pid);
+
+ synchronized (this) {
+ this.exitcode = exitcode;
+ this.hasExited = true;
+ this.notifyAll();
+ }
+
+ if (stdout instanceof DeferredCloseProcessPipeInputStream)
+ ((DeferredCloseProcessPipeInputStream) stdout).processExited();
+
+ if (stderr instanceof DeferredCloseProcessPipeInputStream)
+ ((DeferredCloseProcessPipeInputStream) stderr).processExited();
+
+ if (stdin instanceof ProcessPipeOutputStream)
+ ((ProcessPipeOutputStream) stdin).processExited();
+ });
+ break;
+
+ default: throw new AssertionError("Unsupported platform: " + platform);
+ }
}
public OutputStream getOutputStream() {
return stdin;
}
@@ -290,11 +419,16 @@
}
return exitcode;
}
private static native void destroyProcess(int pid, boolean force);
+
private void destroy(boolean force) {
+ switch (platform) {
+ case LINUX:
+ case BSD:
+ case AIX:
// 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
@@ -304,10 +438,37 @@
destroyProcess(pid, force);
}
try { stdin.close(); } catch (IOException ignored) {}
try { stdout.close(); } catch (IOException ignored) {}
try { stderr.close(); } catch (IOException ignored) {}
+ break;
+
+ case SOLARIS:
+ // 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, force);
+ try {
+ stdin.close();
+ if (stdout_inner_stream != null)
+ stdout_inner_stream.closeDeferred(stdout);
+ if (stderr instanceof DeferredCloseInputStream)
+ ((DeferredCloseInputStream) stderr)
+ .closeDeferred(stderr);
+ } catch (IOException e) {
+ // ignore
+ }
+ }
+ break;
+
+ default: throw new AssertionError("Unsupported platform: " + platform);
+ }
}
public void destroy() {
destroy(false);
}
@@ -336,11 +497,11 @@
*
* 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 {
+ private static class ProcessPipeInputStream extends BufferedInputStream {
private final Object closeLock = new Object();
ProcessPipeInputStream(int fd) {
super(new FileInputStream(newFileDescriptor(fd)));
}
@@ -373,12 +534,12 @@
}
}
@Override
public void close() throws IOException {
- // BufferedInputStream#close() is not synchronized unlike most other methods.
- // Synchronizing helps avoid race with processExited().
+ // BufferedInputStream#close() is not synchronized unlike most other
+ // methods. Synchronizing helps avoid race with processExited().
synchronized (closeLock) {
super.close();
}
}
}
@@ -386,11 +547,11 @@
/**
* 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 {
+ private static class ProcessPipeOutputStream extends BufferedOutputStream {
ProcessPipeOutputStream(int fd) {
super(new FileOutputStream(newFileDescriptor(fd)));
}
/** Called by the process reaper thread when the process exits. */
@@ -405,6 +566,259 @@
}
this.out = ProcessBuilder.NullOutputStream.INSTANCE;
}
}
}
+
+ // A FileInputStream that supports the deferment of the actual close
+ // operation until the last pending I/O operation on the stream has
+ // finished. This is required on Solaris because we must close the stdin
+ // and stdout streams in the destroy method in order to reclaim the
+ // underlying file descriptors. Doing so, however, causes any thread
+ // currently blocked in a read on one of those streams to receive an
+ // IOException("Bad file number"), which is incompatible with historical
+ // behavior. By deferring the close we allow any pending reads to see -1
+ // (EOF) as they did before.
+ //
+ private static class DeferredCloseInputStream extends FileInputStream
+ {
+ DeferredCloseInputStream(FileDescriptor fd) {
+ super(fd);
+ }
+
+ private Object lock = new Object(); // For the following fields
+ private boolean closePending = false;
+ private int useCount = 0;
+ private InputStream streamToClose;
+
+ private void raise() {
+ synchronized (lock) {
+ useCount++;
+ }
+ }
+
+ private void lower() throws IOException {
+ synchronized (lock) {
+ useCount--;
+ if (useCount == 0 && closePending) {
+ streamToClose.close();
+ }
+ }
+ }
+
+ // stc is the actual stream to be closed; it might be this object, or
+ // it might be an upstream object for which this object is downstream.
+ //
+ private void closeDeferred(InputStream stc) throws IOException {
+ synchronized (lock) {
+ if (useCount == 0) {
+ stc.close();
+ } else {
+ closePending = true;
+ streamToClose = stc;
+ }
+ }
+ }
+
+ public void close() throws IOException {
+ synchronized (lock) {
+ useCount = 0;
+ closePending = false;
+ }
+ super.close();
+ }
+
+ public int read() throws IOException {
+ raise();
+ try {
+ return super.read();
+ } finally {
+ lower();
+ }
+ }
+
+ public int read(byte[] b) throws IOException {
+ raise();
+ try {
+ return super.read(b);
+ } finally {
+ lower();
+ }
+ }
+
+ public int read(byte[] b, int off, int len) throws IOException {
+ raise();
+ try {
+ return super.read(b, off, len);
+ } finally {
+ lower();
+ }
+ }
+
+ public long skip(long n) throws IOException {
+ raise();
+ try {
+ return super.skip(n);
+ } finally {
+ lower();
+ }
+ }
+
+ public int available() throws IOException {
+ raise();
+ try {
+ return super.available();
+ } finally {
+ lower();
+ }
+ }
+ }
+
+ /**
+ * 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.
+ *
+ * On AIX this is especially tricky, because the 'close()' system call
+ * will block if another thread is at the same time blocked in a file
+ * operation (e.g. 'read()') on the same file descriptor. We therefore
+ * combine 'ProcessPipeInputStream' approach used on Linux and Bsd
+ * with the DeferredCloseInputStream approach used on Solaris. This means
+ * that every potentially blocking operation on the file descriptor
+ * increments a counter before it is executed and decrements it once it
+ * finishes. The 'close()' operation will only be executed if there are
+ * no pending operations. Otherwise it is deferred after the last pending
+ * operation has finished.
+ *
+ */
+ private static class DeferredCloseProcessPipeInputStream
+ extends BufferedInputStream {
+
+ private final Object closeLock = new Object();
+ private int useCount = 0;
+ private boolean closePending = false;
+
+ DeferredCloseProcessPipeInputStream(int fd) {
+ super(new FileInputStream(newFileDescriptor(fd)));
+ }
+
+ private InputStream drainInputStream(InputStream in)
+ throws IOException {
+ int n = 0;
+ int j;
+ byte[] a = null;
+ synchronized (closeLock) {
+ if (buf == null) // asynchronous close()?
+ return null; // discard
+ j = in.available();
+ }
+ while (j > 0) {
+ a = (a == null) ? new byte[j] : Arrays.copyOf(a, n + j);
+ synchronized (closeLock) {
+ if (buf == null) // asynchronous close()?
+ return null; // discard
+ n += in.read(a, n, j);
+ j = in.available();
+ }
+ }
+ return (a == null) ?
+ ProcessBuilder.NullInputStream.INSTANCE :
+ new ByteArrayInputStream(n == a.length ? a : Arrays.copyOf(a, n));
+ }
+
+ /** Called by the process reaper thread when the process exits. */
+ synchronized void processExited() {
+ try {
+ InputStream in = this.in;
+ if (in != null) {
+ InputStream stragglers = drainInputStream(in);
+ in.close();
+ this.in = stragglers;
+ }
+ } catch (IOException ignored) { }
+ }
+
+ private void raise() {
+ synchronized (closeLock) {
+ useCount++;
+ }
+ }
+
+ private void lower() throws IOException {
+ synchronized (closeLock) {
+ useCount--;
+ if (useCount == 0 && closePending) {
+ closePending = false;
+ super.close();
+ }
+ }
+ }
+
+ @Override
+ public int read() throws IOException {
+ raise();
+ try {
+ return super.read();
+ } finally {
+ lower();
+ }
+ }
+
+ @Override
+ public int read(byte[] b) throws IOException {
+ raise();
+ try {
+ return super.read(b);
+ } finally {
+ lower();
+ }
+ }
+
+ @Override
+ public int read(byte[] b, int off, int len) throws IOException {
+ raise();
+ try {
+ return super.read(b, off, len);
+ } finally {
+ lower();
+ }
+ }
+
+ @Override
+ public long skip(long n) throws IOException {
+ raise();
+ try {
+ return super.skip(n);
+ } finally {
+ lower();
+ }
+ }
+
+ @Override
+ public int available() throws IOException {
+ raise();
+ try {
+ return super.available();
+ } finally {
+ lower();
+ }
+ }
+
+ @Override
+ public void close() throws IOException {
+ // BufferedInputStream#close() is not synchronized unlike most other
+ // methods. Synchronizing helps avoid racing with drainInputStream().
+ synchronized (closeLock) {
+ if (useCount == 0) {
+ super.close();
+ }
+ else {
+ closePending = true;
+ }
+ }
+ }
+ }
}