1 /*
2 * Copyright (c) 2021, 2025, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /*
25 * @test
26 * @bug 8284161 8287008
27 * @summary Basic test for jcmd Thread.dump_to_file
28 * @modules jdk.jcmd
29 * @library /test/lib
30 * @run junit/othervm ThreadDumpToFileTest
31 */
32
33 import java.io.IOException;
34 import java.nio.file.Files;
35 import java.nio.file.Path;
36 import java.util.stream.Stream;
37 import jdk.test.lib.dcmd.PidJcmdExecutor;
38 import jdk.test.lib.process.OutputAnalyzer;
39 import jdk.test.lib.threaddump.ThreadDump;
40
41 import org.junit.jupiter.api.Test;
42 import static org.junit.jupiter.api.Assertions.*;
43
44 class ThreadDumpToFileTest {
45
46 /**
47 * Test thread dump, should be in plain text format.
48 */
49 @Test
50 void testThreadDump() throws IOException {
51 Path file = genThreadDumpPath(".txt");
52 testPlainThreadDump(file);
53 }
54
55 /**
56 * Test thread dump in plain text format.
57 */
58 @Test
59 void testPlainThreadDump() throws IOException {
60 Path file = genThreadDumpPath(".txt");
61 testPlainThreadDump(file, "-format=plain");
62 }
63
64 /**
65 * Test thread dump in JSON format.
66 */
67 @Test
68 void testJsonThreadDump() throws IOException {
69 Path file = genThreadDumpPath(".json");
70 jcmdThreadDumpToFile(file, "-format=json")
71 .shouldMatch("Created");
72
73 // parse the JSON text
74 String jsonText = Files.readString(file);
75 ThreadDump threadDump = ThreadDump.parse(jsonText);
76
77 // test that the process id is this process
78 assertTrue(threadDump.processId() == ProcessHandle.current().pid());
79
80 // test that the current thread is in the root thread container
81 var rootContainer = threadDump.rootThreadContainer();
82 var tid = Thread.currentThread().threadId();
83 rootContainer.findThread(tid).orElseThrow();
84 }
85
86 /**
87 * Test that an existing file is not overwritten.
88 */
89 @Test
90 void testDoNotOverwriteFile() throws IOException {
91 Path file = genThreadDumpPath(".txt");
92 Files.writeString(file, "xxx");
93
94 jcmdThreadDumpToFile(file, "")
95 .shouldMatch("exists");
96
97 // file should not be overridden
98 assertEquals("xxx", Files.readString(file));
99 }
100
101 /**
102 * Test overwriting an existing file.
103 */
104 @Test
105 void testOverwriteFile() throws IOException {
106 Path file = genThreadDumpPath(".txt");
107 Files.writeString(file, "xxx");
108 jcmdThreadDumpToFile(file, "-overwrite")
109 .shouldMatch("Created");
110 }
111
112 /**
113 * Test output file cannot be created.
114 */
115 @Test
116 void testFileCreateFails() throws IOException {
117 Path badFile = Path.of(".").toAbsolutePath()
118 .resolve("does-not-exist")
119 .resolve("does-not-exist")
120 .resolve("threads.bad");
121 jcmdThreadDumpToFile(badFile, "-format=plain")
122 .shouldMatch("Failed");
123 jcmdThreadDumpToFile(badFile, "-format=json")
124 .shouldMatch("Failed");
125 }
126
127 /**
128 * Test thread dump in plain text format.
129 */
130 private void testPlainThreadDump(Path file, String... options) throws IOException {
131 jcmdThreadDumpToFile(file, options).shouldMatch("Created");
132
133 // test that thread dump contains the name and id of the current thread
134 String name = Thread.currentThread().getName();
135 long tid = Thread.currentThread().threadId();
136 String expected = "#" + tid + " \"" + name + "\"";
137 assertTrue(find(file, expected), expected + " not found in " + file);
138 }
139
140 /**
141 * Generate a file path with the given suffix to use for the thread dump.
142 */
143 private Path genThreadDumpPath(String suffix) throws IOException {
144 Path dir = Path.of(".").toAbsolutePath();
145 Path file = Files.createTempFile(dir, "threads-", suffix);
146 Files.delete(file);
147 return file;
148 }
149
150 /**
151 * Launches jcmd Thread.dump_to_file to obtain a thread dump of this VM.
152 */
153 private OutputAnalyzer jcmdThreadDumpToFile(Path file, String... options) {
154 String cmd = "Thread.dump_to_file";
155 for (String option : options) {
156 cmd += " " + option;
157 }
158 return new PidJcmdExecutor().execute(cmd + " " + file);
159 }
160
161 /**
162 * Returns true if the given file contains a line with the string.
163 */
164 private boolean find(Path file, String text) throws IOException {
165 try (Stream<String> stream = Files.lines(file)) {
166 return stream.anyMatch(line -> line.indexOf(text) >= 0);
167 }
168 }
169 }