1 /*
2 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.io.BufferedInputStream;
29 import java.io.BufferedOutputStream;
30 import java.io.ByteArrayInputStream;
31 import java.io.FileDescriptor;
32 import java.io.FileInputStream;
33 import java.io.FileOutputStream;
34 import java.io.IOException;
35 import java.io.InputStream;
36 import java.io.OutputStream;
37 import java.util.Arrays;
38 import java.util.concurrent.Executors;
39 import java.util.concurrent.Executor;
40 import java.util.concurrent.ThreadFactory;
41 import java.util.concurrent.TimeUnit;
42 import java.security.AccessController;
43 import static java.security.AccessController.doPrivileged;
44 import java.security.PrivilegedAction;
45 import java.security.PrivilegedActionException;
46 import java.security.PrivilegedExceptionAction;
47
48 /**
49 * java.lang.Process subclass in the UNIX environment.
50 *
51 * @author Mario Wolczko and Ross Knippel.
52 * @author Konstantin Kladko (ported to Linux)
53 * @author Martin Buchholz
54 */
55 final class UNIXProcess extends Process {
56 private static final sun.misc.JavaIOFileDescriptorAccess fdAccess
57 = sun.misc.SharedSecrets.getJavaIOFileDescriptorAccess();
58
59 private final int pid;
60 private int exitcode;
61 private boolean hasExited;
62
63 private /* final */ OutputStream stdin;
64 private /* final */ InputStream stdout;
65 private /* final */ InputStream stderr;
66
67 private static enum LaunchMechanism {
68 FORK(1),
69 VFORK(3);
70
71 private int value;
72 LaunchMechanism(int x) {value = x;}
73 };
74
75 /* default is VFORK on Linux */
76 private static final LaunchMechanism launchMechanism;
77 private static byte[] helperpath;
78
79 private static byte[] toCString(String s) {
80 if (s == null)
81 return null;
82 byte[] bytes = s.getBytes();
83 byte[] result = new byte[bytes.length + 1];
84 System.arraycopy(bytes, 0,
85 result, 0,
86 bytes.length);
87 result[result.length-1] = (byte)0;
88 return result;
89 }
90
91 static {
92 launchMechanism = AccessController.doPrivileged(
93 new PrivilegedAction<LaunchMechanism>()
94 {
95 public LaunchMechanism run() {
96 String javahome = System.getProperty("java.home");
97 String osArch = System.getProperty("os.arch");
98
99 helperpath = toCString(javahome + "/lib/" + osArch + "/jspawnhelper");
100 String s = System.getProperty(
101 "jdk.lang.Process.launchMechanism", "vfork");
102
103 try {
104 return LaunchMechanism.valueOf(s.toUpperCase());
105 } catch (IllegalArgumentException e) {
106 throw new Error(s + " is not a supported " +
107 "process launch mechanism on this platform.");
108 }
109 }
110 });
111 }
112
113 /* this is for the reaping thread */
114 private native int waitForProcessExit(int pid);
115
116 /**
117 * Create a process. Depending on the mode flag, this is done by
118 * one of the following mechanisms.
119 * - fork(2) and exec(2)
120 * - clone(2) and exec(2)
121 * - vfork(2) and exec(2)
122 *
123 * @param fds an array of three file descriptors.
124 * Indexes 0, 1, and 2 correspond to standard input,
125 * standard output and standard error, respectively. On
126 * input, a value of -1 means to create a pipe to connect
127 * child and parent processes. On output, a value which
128 * is not -1 is the parent pipe fd corresponding to the
129 * pipe which has been created. An element of this array
130 * is -1 on input if and only if it is <em>not</em> -1 on
131 * output.
132 * @return the pid of the subprocess
133 */
134 private native int forkAndExec(int mode, byte[] helperpath,
135 byte[] prog,
136 byte[] argBlock, int argc,
137 byte[] envBlock, int envc,
138 byte[] dir,
139 int[] fds,
140 boolean redirectErrorStream)
141 throws IOException;
142
143 /**
144 * The thread factory used to create "process reaper" daemon threads.
145 */
146 private static class ProcessReaperThreadFactory implements ThreadFactory {
147 private final static ThreadGroup group = getRootThreadGroup();
148
149 private static ThreadGroup getRootThreadGroup() {
150 return doPrivileged(new PrivilegedAction<ThreadGroup> () {
151 public ThreadGroup run() {
152 ThreadGroup root = Thread.currentThread().getThreadGroup();
153 while (root.getParent() != null)
154 root = root.getParent();
155 return root;
156 }});
157 }
158
159 public Thread newThread(Runnable grimReaper) {
160 // Our thread stack requirement is quite modest.
161 Thread t = new Thread(group, grimReaper, "process reaper", 32768);
162 t.setDaemon(true);
163 // A small attempt (probably futile) to avoid priority inversion
164 t.setPriority(Thread.MAX_PRIORITY);
165 return t;
166 }
167 }
168
169 /**
170 * The thread pool of "process reaper" daemon threads.
171 */
172 private static final Executor processReaperExecutor =
173 doPrivileged(new PrivilegedAction<Executor>() {
174 public Executor run() {
175 return Executors.newCachedThreadPool
176 (new ProcessReaperThreadFactory());
177 }});
178
179 UNIXProcess(final byte[] prog,
180 final byte[] argBlock, final int argc,
181 final byte[] envBlock, final int envc,
182 final byte[] dir,
183 final int[] fds,
184 final boolean redirectErrorStream)
185 throws IOException {
186
187 pid = forkAndExec(launchMechanism.value,
188 helperpath,
189 prog,
190 argBlock, argc,
191 envBlock, envc,
192 dir,
193 fds,
194 redirectErrorStream);
195
196 try {
197 doPrivileged(new PrivilegedExceptionAction<Void>() {
198 public Void run() throws IOException {
199 initStreams(fds);
200 return null;
201 }});
202 } catch (PrivilegedActionException ex) {
203 throw (IOException) ex.getException();
204 }
205 }
206
207 static FileDescriptor newFileDescriptor(int fd) {
208 FileDescriptor fileDescriptor = new FileDescriptor();
209 fdAccess.set(fileDescriptor, fd);
210 return fileDescriptor;
211 }
212
213 void initStreams(int[] fds) throws IOException {
214 stdin = (fds[0] == -1) ?
215 ProcessBuilder.NullOutputStream.INSTANCE :
216 new ProcessPipeOutputStream(fds[0]);
217
218 stdout = (fds[1] == -1) ?
219 ProcessBuilder.NullInputStream.INSTANCE :
220 new ProcessPipeInputStream(fds[1]);
221
222 stderr = (fds[2] == -1) ?
223 ProcessBuilder.NullInputStream.INSTANCE :
224 new ProcessPipeInputStream(fds[2]);
225
226 processReaperExecutor.execute(new Runnable() {
227 public void run() {
228 int exitcode = waitForProcessExit(pid);
229 UNIXProcess.this.processExited(exitcode);
230 }});
231 }
232
233 void processExited(int exitcode) {
234 synchronized (this) {
235 this.exitcode = exitcode;
236 hasExited = true;
237 notifyAll();
238 }
239
240 if (stdout instanceof ProcessPipeInputStream)
241 ((ProcessPipeInputStream) stdout).processExited();
242
243 if (stderr instanceof ProcessPipeInputStream)
244 ((ProcessPipeInputStream) stderr).processExited();
245
246 if (stdin instanceof ProcessPipeOutputStream)
247 ((ProcessPipeOutputStream) stdin).processExited();
248 }
249
250 public OutputStream getOutputStream() {
251 return stdin;
252 }
253
254 public InputStream getInputStream() {
255 return stdout;
256 }
257
258 public InputStream getErrorStream() {
259 return stderr;
260 }
261
262 public synchronized int waitFor() throws InterruptedException {
263 while (!hasExited) {
264 wait();
265 }
266 return exitcode;
267 }
275
276 long timeoutAsNanos = unit.toNanos(timeout);
277 long startTime = System.nanoTime();
278 long rem = timeoutAsNanos;
279
280 while (!hasExited && (rem > 0)) {
281 wait(Math.max(TimeUnit.NANOSECONDS.toMillis(rem), 1));
282 rem = timeoutAsNanos - (System.nanoTime() - startTime);
283 }
284 return hasExited;
285 }
286
287 public synchronized int exitValue() {
288 if (!hasExited) {
289 throw new IllegalThreadStateException("process hasn't exited");
290 }
291 return exitcode;
292 }
293
294 private static native void destroyProcess(int pid, boolean force);
295 private void destroy(boolean force) {
296 // There is a risk that pid will be recycled, causing us to
297 // kill the wrong process! So we only terminate processes
298 // that appear to still be running. Even with this check,
299 // there is an unavoidable race condition here, but the window
300 // is very small, and OSes try hard to not recycle pids too
301 // soon, so this is quite safe.
302 synchronized (this) {
303 if (!hasExited)
304 destroyProcess(pid, force);
305 }
306 try { stdin.close(); } catch (IOException ignored) {}
307 try { stdout.close(); } catch (IOException ignored) {}
308 try { stderr.close(); } catch (IOException ignored) {}
309 }
310
311 public void destroy() {
312 destroy(false);
313 }
314
315 @Override
316 public Process destroyForcibly() {
317 destroy(true);
318 return this;
319 }
320
321 @Override
322 public synchronized boolean isAlive() {
323 return !hasExited;
324 }
325
326 private static native void init();
327
328 static {
329 init();
330 }
331
332 /**
333 * A buffered input stream for a subprocess pipe file descriptor
334 * that allows the underlying file descriptor to be reclaimed when
335 * the process exits, via the processExited hook.
336 *
337 * This is tricky because we do not want the user-level InputStream to be
338 * closed until the user invokes close(), and we need to continue to be
339 * able to read any buffered data lingering in the OS pipe buffer.
340 */
341 static class ProcessPipeInputStream extends BufferedInputStream {
342 private final Object closeLock = new Object();
343
344 ProcessPipeInputStream(int fd) {
345 super(new FileInputStream(newFileDescriptor(fd)));
346 }
347 private static byte[] drainInputStream(InputStream in)
348 throws IOException {
349 int n = 0;
350 int j;
351 byte[] a = null;
352 while ((j = in.available()) > 0) {
353 a = (a == null) ? new byte[j] : Arrays.copyOf(a, n + j);
354 n += in.read(a, n, j);
355 }
356 return (a == null || n == a.length) ? a : Arrays.copyOf(a, n);
357 }
358
359 /** Called by the process reaper thread when the process exits. */
360 synchronized void processExited() {
361 synchronized (closeLock) {
362 try {
363 InputStream in = this.in;
364 // this stream is closed if and only if: in == null
365 if (in != null) {
366 byte[] stragglers = drainInputStream(in);
367 in.close();
368 this.in = (stragglers == null) ?
369 ProcessBuilder.NullInputStream.INSTANCE :
370 new ByteArrayInputStream(stragglers);
371 }
372 } catch (IOException ignored) {}
373 }
374 }
375
376 @Override
377 public void close() throws IOException {
378 // BufferedInputStream#close() is not synchronized unlike most other methods.
379 // Synchronizing helps avoid race with processExited().
380 synchronized (closeLock) {
381 super.close();
382 }
383 }
384 }
385
386 /**
387 * A buffered output stream for a subprocess pipe file descriptor
388 * that allows the underlying file descriptor to be reclaimed when
389 * the process exits, via the processExited hook.
390 */
391 static class ProcessPipeOutputStream extends BufferedOutputStream {
392 ProcessPipeOutputStream(int fd) {
393 super(new FileOutputStream(newFileDescriptor(fd)));
394 }
395
396 /** Called by the process reaper thread when the process exits. */
397 synchronized void processExited() {
398 OutputStream out = this.out;
399 if (out != null) {
400 try {
401 out.close();
402 } catch (IOException ignored) {
403 // We know of no reason to get an IOException, but if
404 // we do, there's nothing else to do but carry on.
405 }
406 this.out = ProcessBuilder.NullOutputStream.INSTANCE;
407 }
408 }
409 }
410 }
|
1 /*
2 * Copyright (c) 1995, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import java.io.BufferedInputStream;
29 import java.io.BufferedOutputStream;
30 import java.io.ByteArrayInputStream;
31 import java.io.FileDescriptor;
32 import java.io.FileInputStream;
33 import java.io.FileOutputStream;
34 import java.io.IOException;
35 import java.io.InputStream;
36 import java.io.OutputStream;
37 import java.util.Arrays;
38 import java.util.EnumSet;
39 import java.util.Locale;
40 import java.util.Set;
41 import java.util.concurrent.Executors;
42 import java.util.concurrent.Executor;
43 import java.util.concurrent.TimeUnit;
44 import java.security.AccessController;
45 import static java.security.AccessController.doPrivileged;
46 import java.security.PrivilegedAction;
47 import java.security.PrivilegedActionException;
48 import java.security.PrivilegedExceptionAction;
49
50 /**
51 * java.lang.Process subclass in the UNIX environment.
52 *
53 * @author Mario Wolczko and Ross Knippel.
54 * @author Konstantin Kladko (ported to Linux and Bsd)
55 * @author Martin Buchholz
56 * @author Volker Simonis (ported to AIX)
57 */
58 final class UNIXProcess extends Process {
59 private static final sun.misc.JavaIOFileDescriptorAccess fdAccess
60 = sun.misc.SharedSecrets.getJavaIOFileDescriptorAccess();
61
62 private final int pid;
63 private int exitcode;
64 private boolean hasExited;
65
66 private /* final */ OutputStream stdin;
67 private /* final */ InputStream stdout;
68 private /* final */ InputStream stderr;
69
70 // only used on Solaris
71 private /* final */ DeferredCloseInputStream stdout_inner_stream;
72
73 private static enum LaunchMechanism {
74 // order IS important!
75 FORK,
76 POSIX_SPAWN,
77 VFORK
78 }
79
80 private static enum Platform {
81
82 LINUX(LaunchMechanism.VFORK, LaunchMechanism.FORK),
83
84 BSD(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK),
85
86 SOLARIS(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK),
87
88 AIX(LaunchMechanism.POSIX_SPAWN, LaunchMechanism.FORK);
89
90 final LaunchMechanism defaultLaunchMechanism;
91 final Set<LaunchMechanism> validLaunchMechanisms;
92
93 Platform(LaunchMechanism ... launchMechanisms) {
94 this.defaultLaunchMechanism = launchMechanisms[0];
95 this.validLaunchMechanisms =
96 EnumSet.copyOf(Arrays.asList(launchMechanisms));
97 }
98
99 private String helperPath(String javahome, String osArch) {
100 switch (this) {
101 case SOLARIS:
102 if (osArch.equals("x86")) { osArch = "i386"; }
103 else if (osArch.equals("x86_64")) { osArch = "amd64"; }
104 // fall through...
105 case LINUX:
106 case AIX:
107 return javahome + "/lib/" + osArch + "/jspawnhelper";
108
109 case BSD:
110 return javahome + "/lib/jspawnhelper";
111
112 default:
113 throw new AssertionError("Unsupported platform: " + this);
114 }
115 }
116
117 String helperPath() {
118 return AccessController.doPrivileged(
119 (PrivilegedAction<String>) () ->
120 helperPath(System.getProperty("java.home"),
121 System.getProperty("os.arch"))
122 );
123 }
124
125 LaunchMechanism launchMechanism() {
126 return AccessController.doPrivileged(
127 (PrivilegedAction<LaunchMechanism>) () -> {
128 String s = System.getProperty(
129 "jdk.lang.Process.launchMechanism");
130 LaunchMechanism lm;
131 if (s == null) {
132 lm = defaultLaunchMechanism;
133 s = lm.name().toLowerCase(Locale.ENGLISH);
134 } else {
135 try {
136 lm = LaunchMechanism.valueOf(
137 s.toUpperCase(Locale.ENGLISH));
138 } catch (IllegalArgumentException e) {
139 lm = null;
140 }
141 }
142 if (lm == null || !validLaunchMechanisms.contains(lm)) {
143 throw new Error(
144 s + " is not a supported " +
145 "process launch mechanism on this platform."
146 );
147 }
148 return lm;
149 }
150 );
151 }
152
153 static Platform get() {
154 String osName = AccessController.doPrivileged(
155 (PrivilegedAction<String>) () -> System.getProperty("os.name")
156 );
157
158 if (osName.equals("Linux")) { return LINUX; }
159 if (osName.contains("OS X")) { return BSD; }
160 if (osName.equals("SunOS")) { return SOLARIS; }
161 if (osName.equals("AIX")) { return AIX; }
162
163 throw new Error(osName + " is not a supported OS platform.");
164 }
165 }
166
167 private static final Platform platform = Platform.get();
168 private static final LaunchMechanism launchMechanism = platform.launchMechanism();
169 private static final byte[] helperpath = toCString(platform.helperPath());
170
171 private static byte[] toCString(String s) {
172 if (s == null)
173 return null;
174 byte[] bytes = s.getBytes();
175 byte[] result = new byte[bytes.length + 1];
176 System.arraycopy(bytes, 0,
177 result, 0,
178 bytes.length);
179 result[result.length-1] = (byte)0;
180 return result;
181 }
182
183 /* this is for the reaping thread */
184 private native int waitForProcessExit(int pid);
185
186 /**
187 * Create a process. Depending on the mode flag, this is done by
188 * one of the following mechanisms.
189 * - fork(2) and exec(2)
190 * - clone(2) and exec(2)
191 * - vfork(2) and exec(2)
192 *
193 * @param fds an array of three file descriptors.
194 * Indexes 0, 1, and 2 correspond to standard input,
195 * standard output and standard error, respectively. On
196 * input, a value of -1 means to create a pipe to connect
197 * child and parent processes. On output, a value which
198 * is not -1 is the parent pipe fd corresponding to the
199 * pipe which has been created. An element of this array
200 * is -1 on input if and only if it is <em>not</em> -1 on
201 * output.
202 * @return the pid of the subprocess
203 */
204 private native int forkAndExec(int mode, byte[] helperpath,
205 byte[] prog,
206 byte[] argBlock, int argc,
207 byte[] envBlock, int envc,
208 byte[] dir,
209 int[] fds,
210 boolean redirectErrorStream)
211 throws IOException;
212
213 /**
214 * Root thread group for threads created by processReaperExecutor's
215 * ThreadFactory
216 */
217 private static final ThreadGroup rootThreadGroup =
218 doPrivileged((PrivilegedAction<ThreadGroup>) () -> {
219 ThreadGroup root = Thread.currentThread().getThreadGroup();
220 while (root.getParent() != null)
221 root = root.getParent();
222 return root;
223 });
224
225 /**
226 * The thread pool of "process reaper" daemon threads.
227 */
228 private static final Executor processReaperExecutor =
229 Executors.newCachedThreadPool(grimReaper -> {
230 // Our thread stack requirement is quite modest.
231 Thread t = new Thread(rootThreadGroup, grimReaper,
232 "process reaper", 32768);
233 t.setDaemon(true);
234 // A small attempt (probably futile) to avoid priority inversion
235 t.setPriority(Thread.MAX_PRIORITY);
236 return t;
237 });
238
239 UNIXProcess(final byte[] prog,
240 final byte[] argBlock, final int argc,
241 final byte[] envBlock, final int envc,
242 final byte[] dir,
243 final int[] fds,
244 final boolean redirectErrorStream)
245 throws IOException {
246
247 pid = forkAndExec(launchMechanism.ordinal() + 1,
248 helperpath,
249 prog,
250 argBlock, argc,
251 envBlock, envc,
252 dir,
253 fds,
254 redirectErrorStream);
255
256 try {
257 doPrivileged((PrivilegedExceptionAction<Void>) () -> {
258 initStreams(fds);
259 return null;
260 });
261 } catch (PrivilegedActionException ex) {
262 throw (IOException) ex.getException();
263 }
264 }
265
266 static FileDescriptor newFileDescriptor(int fd) {
267 FileDescriptor fileDescriptor = new FileDescriptor();
268 fdAccess.set(fileDescriptor, fd);
269 return fileDescriptor;
270 }
271
272 void initStreams(int[] fds) throws IOException {
273 switch (platform) {
274 case LINUX:
275 case BSD:
276 stdin = (fds[0] == -1) ?
277 ProcessBuilder.NullOutputStream.INSTANCE :
278 new ProcessPipeOutputStream(fds[0]);
279
280 stdout = (fds[1] == -1) ?
281 ProcessBuilder.NullInputStream.INSTANCE :
282 new ProcessPipeInputStream(fds[1]);
283
284 stderr = (fds[2] == -1) ?
285 ProcessBuilder.NullInputStream.INSTANCE :
286 new ProcessPipeInputStream(fds[2]);
287
288 processReaperExecutor.execute(() -> {
289 int exitcode = waitForProcessExit(pid);
290
291 synchronized (this) {
292 this.exitcode = exitcode;
293 this.hasExited = true;
294 this.notifyAll();
295 }
296
297 if (stdout instanceof ProcessPipeInputStream)
298 ((ProcessPipeInputStream) stdout).processExited();
299
300 if (stderr instanceof ProcessPipeInputStream)
301 ((ProcessPipeInputStream) stderr).processExited();
302
303 if (stdin instanceof ProcessPipeOutputStream)
304 ((ProcessPipeOutputStream) stdin).processExited();
305 });
306 break;
307
308 case SOLARIS:
309 stdin = (fds[0] == -1) ?
310 ProcessBuilder.NullOutputStream.INSTANCE :
311 new BufferedOutputStream(
312 new FileOutputStream(newFileDescriptor(fds[0])));
313
314 stdout = (fds[1] == -1) ?
315 ProcessBuilder.NullInputStream.INSTANCE :
316 new BufferedInputStream(
317 stdout_inner_stream =
318 new DeferredCloseInputStream(
319 newFileDescriptor(fds[1])));
320
321 stderr = (fds[2] == -1) ?
322 ProcessBuilder.NullInputStream.INSTANCE :
323 new DeferredCloseInputStream(newFileDescriptor(fds[2]));
324
325 /*
326 * For each subprocess forked a corresponding reaper task
327 * is submitted. That task is the only thread which waits
328 * for the subprocess to terminate and it doesn't hold any
329 * locks while doing so. This design allows waitFor() and
330 * exitStatus() to be safely executed in parallel (and they
331 * need no native code).
332 */
333 processReaperExecutor.execute(() -> {
334 int exitcode = waitForProcessExit(pid);
335
336 synchronized (this) {
337 this.exitcode = exitcode;
338 this.hasExited = true;
339 this.notifyAll();
340 }
341 });
342 break;
343
344 case AIX:
345 stdin = (fds[0] == -1) ?
346 ProcessBuilder.NullOutputStream.INSTANCE :
347 new ProcessPipeOutputStream(fds[0]);
348
349 stdout = (fds[1] == -1) ?
350 ProcessBuilder.NullInputStream.INSTANCE :
351 new DeferredCloseProcessPipeInputStream(fds[1]);
352
353 stderr = (fds[2] == -1) ?
354 ProcessBuilder.NullInputStream.INSTANCE :
355 new DeferredCloseProcessPipeInputStream(fds[2]);
356
357 processReaperExecutor.execute(() -> {
358 int exitcode = waitForProcessExit(pid);
359
360 synchronized (this) {
361 this.exitcode = exitcode;
362 this.hasExited = true;
363 this.notifyAll();
364 }
365
366 if (stdout instanceof DeferredCloseProcessPipeInputStream)
367 ((DeferredCloseProcessPipeInputStream) stdout).processExited();
368
369 if (stderr instanceof DeferredCloseProcessPipeInputStream)
370 ((DeferredCloseProcessPipeInputStream) stderr).processExited();
371
372 if (stdin instanceof ProcessPipeOutputStream)
373 ((ProcessPipeOutputStream) stdin).processExited();
374 });
375 break;
376
377 default: throw new AssertionError("Unsupported platform: " + platform);
378 }
379 }
380
381 public OutputStream getOutputStream() {
382 return stdin;
383 }
384
385 public InputStream getInputStream() {
386 return stdout;
387 }
388
389 public InputStream getErrorStream() {
390 return stderr;
391 }
392
393 public synchronized int waitFor() throws InterruptedException {
394 while (!hasExited) {
395 wait();
396 }
397 return exitcode;
398 }
406
407 long timeoutAsNanos = unit.toNanos(timeout);
408 long startTime = System.nanoTime();
409 long rem = timeoutAsNanos;
410
411 while (!hasExited && (rem > 0)) {
412 wait(Math.max(TimeUnit.NANOSECONDS.toMillis(rem), 1));
413 rem = timeoutAsNanos - (System.nanoTime() - startTime);
414 }
415 return hasExited;
416 }
417
418 public synchronized int exitValue() {
419 if (!hasExited) {
420 throw new IllegalThreadStateException("process hasn't exited");
421 }
422 return exitcode;
423 }
424
425 private static native void destroyProcess(int pid, boolean force);
426
427 private void destroy(boolean force) {
428 switch (platform) {
429 case LINUX:
430 case BSD:
431 case AIX:
432 // There is a risk that pid will be recycled, causing us to
433 // kill the wrong process! So we only terminate processes
434 // that appear to still be running. Even with this check,
435 // there is an unavoidable race condition here, but the window
436 // is very small, and OSes try hard to not recycle pids too
437 // soon, so this is quite safe.
438 synchronized (this) {
439 if (!hasExited)
440 destroyProcess(pid, force);
441 }
442 try { stdin.close(); } catch (IOException ignored) {}
443 try { stdout.close(); } catch (IOException ignored) {}
444 try { stderr.close(); } catch (IOException ignored) {}
445 break;
446
447 case SOLARIS:
448 // There is a risk that pid will be recycled, causing us to
449 // kill the wrong process! So we only terminate processes
450 // that appear to still be running. Even with this check,
451 // there is an unavoidable race condition here, but the window
452 // is very small, and OSes try hard to not recycle pids too
453 // soon, so this is quite safe.
454 synchronized (this) {
455 if (!hasExited)
456 destroyProcess(pid, force);
457 try {
458 stdin.close();
459 if (stdout_inner_stream != null)
460 stdout_inner_stream.closeDeferred(stdout);
461 if (stderr instanceof DeferredCloseInputStream)
462 ((DeferredCloseInputStream) stderr)
463 .closeDeferred(stderr);
464 } catch (IOException e) {
465 // ignore
466 }
467 }
468 break;
469
470 default: throw new AssertionError("Unsupported platform: " + platform);
471 }
472 }
473
474 public void destroy() {
475 destroy(false);
476 }
477
478 @Override
479 public Process destroyForcibly() {
480 destroy(true);
481 return this;
482 }
483
484 @Override
485 public synchronized boolean isAlive() {
486 return !hasExited;
487 }
488
489 private static native void init();
490
491 static {
492 init();
493 }
494
495 /**
496 * A buffered input stream for a subprocess pipe file descriptor
497 * that allows the underlying file descriptor to be reclaimed when
498 * the process exits, via the processExited hook.
499 *
500 * This is tricky because we do not want the user-level InputStream to be
501 * closed until the user invokes close(), and we need to continue to be
502 * able to read any buffered data lingering in the OS pipe buffer.
503 */
504 private static class ProcessPipeInputStream extends BufferedInputStream {
505 private final Object closeLock = new Object();
506
507 ProcessPipeInputStream(int fd) {
508 super(new FileInputStream(newFileDescriptor(fd)));
509 }
510 private static byte[] drainInputStream(InputStream in)
511 throws IOException {
512 int n = 0;
513 int j;
514 byte[] a = null;
515 while ((j = in.available()) > 0) {
516 a = (a == null) ? new byte[j] : Arrays.copyOf(a, n + j);
517 n += in.read(a, n, j);
518 }
519 return (a == null || n == a.length) ? a : Arrays.copyOf(a, n);
520 }
521
522 /** Called by the process reaper thread when the process exits. */
523 synchronized void processExited() {
524 synchronized (closeLock) {
525 try {
526 InputStream in = this.in;
527 // this stream is closed if and only if: in == null
528 if (in != null) {
529 byte[] stragglers = drainInputStream(in);
530 in.close();
531 this.in = (stragglers == null) ?
532 ProcessBuilder.NullInputStream.INSTANCE :
533 new ByteArrayInputStream(stragglers);
534 }
535 } catch (IOException ignored) {}
536 }
537 }
538
539 @Override
540 public void close() throws IOException {
541 // BufferedInputStream#close() is not synchronized unlike most other
542 // methods. Synchronizing helps avoid race with processExited().
543 synchronized (closeLock) {
544 super.close();
545 }
546 }
547 }
548
549 /**
550 * A buffered output stream for a subprocess pipe file descriptor
551 * that allows the underlying file descriptor to be reclaimed when
552 * the process exits, via the processExited hook.
553 */
554 private static class ProcessPipeOutputStream extends BufferedOutputStream {
555 ProcessPipeOutputStream(int fd) {
556 super(new FileOutputStream(newFileDescriptor(fd)));
557 }
558
559 /** Called by the process reaper thread when the process exits. */
560 synchronized void processExited() {
561 OutputStream out = this.out;
562 if (out != null) {
563 try {
564 out.close();
565 } catch (IOException ignored) {
566 // We know of no reason to get an IOException, but if
567 // we do, there's nothing else to do but carry on.
568 }
569 this.out = ProcessBuilder.NullOutputStream.INSTANCE;
570 }
571 }
572 }
573
574 // A FileInputStream that supports the deferment of the actual close
575 // operation until the last pending I/O operation on the stream has
576 // finished. This is required on Solaris because we must close the stdin
577 // and stdout streams in the destroy method in order to reclaim the
578 // underlying file descriptors. Doing so, however, causes any thread
579 // currently blocked in a read on one of those streams to receive an
580 // IOException("Bad file number"), which is incompatible with historical
581 // behavior. By deferring the close we allow any pending reads to see -1
582 // (EOF) as they did before.
583 //
584 private static class DeferredCloseInputStream extends FileInputStream
585 {
586 DeferredCloseInputStream(FileDescriptor fd) {
587 super(fd);
588 }
589
590 private Object lock = new Object(); // For the following fields
591 private boolean closePending = false;
592 private int useCount = 0;
593 private InputStream streamToClose;
594
595 private void raise() {
596 synchronized (lock) {
597 useCount++;
598 }
599 }
600
601 private void lower() throws IOException {
602 synchronized (lock) {
603 useCount--;
604 if (useCount == 0 && closePending) {
605 streamToClose.close();
606 }
607 }
608 }
609
610 // stc is the actual stream to be closed; it might be this object, or
611 // it might be an upstream object for which this object is downstream.
612 //
613 private void closeDeferred(InputStream stc) throws IOException {
614 synchronized (lock) {
615 if (useCount == 0) {
616 stc.close();
617 } else {
618 closePending = true;
619 streamToClose = stc;
620 }
621 }
622 }
623
624 public void close() throws IOException {
625 synchronized (lock) {
626 useCount = 0;
627 closePending = false;
628 }
629 super.close();
630 }
631
632 public int read() throws IOException {
633 raise();
634 try {
635 return super.read();
636 } finally {
637 lower();
638 }
639 }
640
641 public int read(byte[] b) throws IOException {
642 raise();
643 try {
644 return super.read(b);
645 } finally {
646 lower();
647 }
648 }
649
650 public int read(byte[] b, int off, int len) throws IOException {
651 raise();
652 try {
653 return super.read(b, off, len);
654 } finally {
655 lower();
656 }
657 }
658
659 public long skip(long n) throws IOException {
660 raise();
661 try {
662 return super.skip(n);
663 } finally {
664 lower();
665 }
666 }
667
668 public int available() throws IOException {
669 raise();
670 try {
671 return super.available();
672 } finally {
673 lower();
674 }
675 }
676 }
677
678 /**
679 * A buffered input stream for a subprocess pipe file descriptor
680 * that allows the underlying file descriptor to be reclaimed when
681 * the process exits, via the processExited hook.
682 *
683 * This is tricky because we do not want the user-level InputStream to be
684 * closed until the user invokes close(), and we need to continue to be
685 * able to read any buffered data lingering in the OS pipe buffer.
686 *
687 * On AIX this is especially tricky, because the 'close()' system call
688 * will block if another thread is at the same time blocked in a file
689 * operation (e.g. 'read()') on the same file descriptor. We therefore
690 * combine 'ProcessPipeInputStream' approach used on Linux and Bsd
691 * with the DeferredCloseInputStream approach used on Solaris. This means
692 * that every potentially blocking operation on the file descriptor
693 * increments a counter before it is executed and decrements it once it
694 * finishes. The 'close()' operation will only be executed if there are
695 * no pending operations. Otherwise it is deferred after the last pending
696 * operation has finished.
697 *
698 */
699 private static class DeferredCloseProcessPipeInputStream
700 extends BufferedInputStream {
701
702 private final Object closeLock = new Object();
703 private int useCount = 0;
704 private boolean closePending = false;
705
706 DeferredCloseProcessPipeInputStream(int fd) {
707 super(new FileInputStream(newFileDescriptor(fd)));
708 }
709
710 private InputStream drainInputStream(InputStream in)
711 throws IOException {
712 int n = 0;
713 int j;
714 byte[] a = null;
715 synchronized (closeLock) {
716 if (buf == null) // asynchronous close()?
717 return null; // discard
718 j = in.available();
719 }
720 while (j > 0) {
721 a = (a == null) ? new byte[j] : Arrays.copyOf(a, n + j);
722 synchronized (closeLock) {
723 if (buf == null) // asynchronous close()?
724 return null; // discard
725 n += in.read(a, n, j);
726 j = in.available();
727 }
728 }
729 return (a == null) ?
730 ProcessBuilder.NullInputStream.INSTANCE :
731 new ByteArrayInputStream(n == a.length ? a : Arrays.copyOf(a, n));
732 }
733
734 /** Called by the process reaper thread when the process exits. */
735 synchronized void processExited() {
736 try {
737 InputStream in = this.in;
738 if (in != null) {
739 InputStream stragglers = drainInputStream(in);
740 in.close();
741 this.in = stragglers;
742 }
743 } catch (IOException ignored) { }
744 }
745
746 private void raise() {
747 synchronized (closeLock) {
748 useCount++;
749 }
750 }
751
752 private void lower() throws IOException {
753 synchronized (closeLock) {
754 useCount--;
755 if (useCount == 0 && closePending) {
756 closePending = false;
757 super.close();
758 }
759 }
760 }
761
762 @Override
763 public int read() throws IOException {
764 raise();
765 try {
766 return super.read();
767 } finally {
768 lower();
769 }
770 }
771
772 @Override
773 public int read(byte[] b) throws IOException {
774 raise();
775 try {
776 return super.read(b);
777 } finally {
778 lower();
779 }
780 }
781
782 @Override
783 public int read(byte[] b, int off, int len) throws IOException {
784 raise();
785 try {
786 return super.read(b, off, len);
787 } finally {
788 lower();
789 }
790 }
791
792 @Override
793 public long skip(long n) throws IOException {
794 raise();
795 try {
796 return super.skip(n);
797 } finally {
798 lower();
799 }
800 }
801
802 @Override
803 public int available() throws IOException {
804 raise();
805 try {
806 return super.available();
807 } finally {
808 lower();
809 }
810 }
811
812 @Override
813 public void close() throws IOException {
814 // BufferedInputStream#close() is not synchronized unlike most other
815 // methods. Synchronizing helps avoid racing with drainInputStream().
816 synchronized (closeLock) {
817 if (useCount == 0) {
818 super.close();
819 }
820 else {
821 closePending = true;
822 }
823 }
824 }
825 }
826 }
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