1 import static java.io.File.createTempFile;
2 import static java.lang.Long.parseLong;
3 import static java.lang.System.getProperty;
4 import static java.lang.management.ManagementFactory.getOperatingSystemMXBean;
5 import static java.nio.file.Files.readAllBytes;
6 import static jdk.test.lib.process.ProcessTools.createJavaProcessBuilder;
7
8 import java.io.File;
9 import java.io.IOException;
10
11 import com.sun.management.UnixOperatingSystemMXBean;
12
13 /*
14 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
15 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
16 *
17 * This code is free software; you can redistribute it and/or modify it
18 * under the terms of the GNU General Public License version 2 only, as
19 * published by the Free Software Foundation.
20 *
21 * This code is distributed in the hope that it will be useful, but WITHOUT
22 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
23 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
24 * version 2 for more details (a copy is included in the LICENSE file that
25 * accompanied this code).
26 *
27 * You should have received a copy of the GNU General Public License version
28 * 2 along with this work; if not, write to the Free Software Foundation,
29 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
30 *
31 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
32 * or visit www.oracle.com if you need additional information or have any
33 * questions.
34 */
35
36 /*
37 * @test TestInheritFD
38 * @bug 8176717 8176809
39 * @summary a new process should not inherit open file descriptors
40 * @library /test/lib
41 * @modules java.base/jdk.internal.misc
42 * java.management
43 */
44
45 /**
46 * Test that HotSpot does not leak logging file descriptors.
47 *
48 * This test is performed in three steps. The first VM starts a second VM with
49 * gc logging enabled. The second VM starts a third VM and redirects the third
50 * VMs output to the first VM, it then exits and hopefully closes its log file.
51 *
52 * The third VM waits for the second to exit and close its log file. After that,
53 * the third VM tries to rename the log file of the second VM. If it succeeds in
54 * doing so it means that the third VM did not inherit the open log file
55 * (windows can not rename opened files easily)
56 *
57 * The third VM communicates the success to rename the file by printing "CLOSED
58 * FD". The first VM checks that the string was printed by the third VM.
59 *
60 * On unix like systems, UnixOperatingSystemMXBean is used to check open file
61 * descriptors.
62 */
63
64 public class TestInheritFD {
65
66 public static final String LEAKS_FD = "VM RESULT => LEAKS FD";
67 public static final String RETAINS_FD = "VM RESULT => RETAINS FD";
68 public static final String EXIT = "VM RESULT => VM EXIT";
69
70 // first VM
71 public static void main(String[] args) throws Exception {
72 String logPath = createTempFile("logging", ".log").getName();
73 File commFile = createTempFile("communication", ".txt");
74
75 ProcessBuilder pb = createJavaProcessBuilder(
76 "-Xlog:gc:\"" + logPath + "\"",
77 "-Dtest.jdk=" + getProperty("test.jdk"),
78 VMStartedWithLogging.class.getName(),
79 logPath);
80
81 pb.redirectOutput(commFile); // use temp file to communicate between processes
82 pb.start();
83
84 String out = "";
85 do {
86 out = new String(readAllBytes(commFile.toPath()));
87 Thread.sleep(100);
88 System.out.println("SLEEP 100 millis");
89 } while (!out.contains(EXIT));
90
91 System.out.println(out);
92 if (out.contains(RETAINS_FD)) {
93 System.out.println("Log file was not inherited by third VM");
94 } else {
95 throw new RuntimeException("could not match: " + RETAINS_FD);
96 }
97 }
98
99 static class VMStartedWithLogging {
100 // second VM
101 public static void main(String[] args) throws IOException, InterruptedException {
102 ProcessBuilder pb = createJavaProcessBuilder(
103 "-Dtest.jdk=" + getProperty("test.jdk"),
104 VMShouldNotInheritFileDescriptors.class.getName(),
105 args[0],
106 "" + ProcessHandle.current().pid(),
107 "" + (supportsUnixMXBean()?+unixNrFD():-1));
108 pb.inheritIO(); // in future, redirect information from third VM to first VM
109 pb.start();
110 }
111 }
112
113 static class VMShouldNotInheritFileDescriptors {
114 // third VM
115 public static void main(String[] args) throws InterruptedException {
116 File logFile = new File(args[0]);
117 long parentPid = parseLong(args[1]);
118 long parentFDCount = parseLong(args[2]);
119
120 if(supportsUnixMXBean()){
121 long thisFDCount = unixNrFD();
122 System.out.println("This VM FD-count (" + thisFDCount + ") should be strictly less than parent VM FD-count (" + parentFDCount + ") as log file should have been closed");
123 System.out.println(thisFDCount<parentFDCount?RETAINS_FD:LEAKS_FD);
124 } else if (getProperty("os.name").toLowerCase().contains("win")) {
125 windows(logFile, parentPid);
126 } else {
127 System.out.println(LEAKS_FD); // default fail on unknown configuration
128 }
129 System.out.println(EXIT);
130 }
131 }
132
133 static boolean supportsUnixMXBean() {
134 return getOperatingSystemMXBean() instanceof UnixOperatingSystemMXBean;
135 }
136
137 static long unixNrFD() {
138 UnixOperatingSystemMXBean osBean = (UnixOperatingSystemMXBean) getOperatingSystemMXBean();
139 return osBean.getOpenFileDescriptorCount();
140 }
141
142 static void windows(File f, long parentPid) throws InterruptedException {
143 System.out.println("waiting for pid: " + parentPid);
144 ProcessHandle.of(parentPid).ifPresent(handle -> handle.onExit().join());
145 System.out.println("trying to rename file to the same name: " + f);
146 System.out.println(f.renameTo(f)?RETAINS_FD:LEAKS_FD); // this parts communicates a closed file descriptor by printing "CLOSED FD"
147 }