1 /*
   2  * Copyright (c) 2013, 2015, 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 7162400
  27  * @key regression
  28  * @summary Regression test for attach issue where stale pid files in /tmp lead to connection issues
  29  * @modules jdk.attach/sun.tools.attach
  30  * @library /testlibrary
  31  * @build jdk.test.lib.* AttachWithStalePidFileTarget
  32  * @run main AttachWithStalePidFile
  33  */
  34 
  35 import jdk.test.lib.*;
  36 import com.sun.tools.attach.VirtualMachine;
  37 import sun.tools.attach.HotSpotVirtualMachine;
  38 import java.lang.reflect.Field;
  39 import java.nio.file.*;
  40 import java.nio.file.attribute.*;
  41 import java.io.*;
  42 
  43 public class AttachWithStalePidFile {
  44   public static void main(String... args) throws Exception {
  45 
  46     // this test is only valid on non-Windows platforms
  47     if(Platform.isWindows()) {
  48       System.out.println("This test is only valid on non-Windows platforms.");
  49       return;
  50     }
  51 
  52     // Since there might be stale pid-files owned by different
  53     // users on the system we may need to retry the test in case we
  54     // are unable to remove the existing file.
  55     int retries = 5;
  56     while(!runTest() && --retries > 0);
  57 
  58     if(retries == 0) {
  59       throw new RuntimeException("Test failed after 5 retries. " +
  60         "Remove any /tmp/.java_pid* files and retry.");
  61     }
  62   }
  63 
  64   public static boolean runTest() throws Exception {
  65     ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
  66       "-XX:+UnlockDiagnosticVMOptions", "-XX:+PauseAtStartup", "AttachWithStalePidFileTarget");
  67     Process target = pb.start();
  68     Path pidFile = null;
  69 
  70     try {
  71       int pid = getUnixProcessId(target);
  72 
  73       // create the stale .java_pid file. use hard-coded /tmp path as in th VM
  74       pidFile = createJavaPidFile(pid);
  75       if(pidFile == null) {
  76         return false;
  77       }
  78 
  79       // wait for vm.paused file to be created and delete it once we find it.
  80       waitForAndResumeVM(pid);
  81 
  82       waitForTargetReady(target);
  83 
  84       HotSpotVirtualMachine vm = (HotSpotVirtualMachine)VirtualMachine.attach(((Integer)pid).toString());
  85       BufferedReader remoteDataReader = new BufferedReader(new InputStreamReader(vm.remoteDataDump()));
  86       String line = null;
  87       while((line = remoteDataReader.readLine()) != null);
  88 
  89       vm.detach();
  90       return true;
  91     }
  92     finally {
  93       target.destroy();
  94       target.waitFor();
  95 
  96       if(pidFile != null && Files.exists(pidFile)) {
  97         Files.delete(pidFile);
  98       }
  99     }
 100   }
 101 
 102   private static void waitForTargetReady(Process target) throws IOException {
 103     BufferedReader br = new BufferedReader(new InputStreamReader(target.getInputStream()));
 104     String line = br.readLine();
 105     // wait for the ready message having been printed or EOF (line == null)
 106     while (line != null && !line.equals(AttachWithStalePidFileTarget.READY_MSG)) {
 107         line = br.readLine();
 108     }
 109     // target VM ready
 110   }
 111 
 112   private static Path createJavaPidFile(int pid) throws Exception {
 113     Path pidFile = Paths.get("/tmp/.java_pid" + pid);
 114     if(Files.exists(pidFile)) {
 115       try {
 116         Files.delete(pidFile);
 117       }
 118       catch(FileSystemException e) {
 119         if(e.getReason().matches("Operation not permitted|Not owner")) {
 120           System.out.println("Unable to remove exisiting stale PID file" + pidFile);
 121           System.out.println("===================================================");
 122           e.printStackTrace(System.out);
 123           return null;
 124         }
 125         throw e;
 126       }
 127     }
 128     return Files.createFile(pidFile,
 129       PosixFilePermissions.asFileAttribute(PosixFilePermissions.fromString("rw-------")));
 130   }
 131 
 132   private static void waitForAndResumeVM(int pid) throws Exception {
 133     Path pauseFile = Paths.get("vm.paused." + pid);
 134     int retries = 60;
 135     while(!Files.exists(pauseFile) && --retries > 0) {
 136       Thread.sleep(1000);
 137     }
 138     if(retries == 0) {
 139       throw new RuntimeException("Timeout waiting for VM to start. " +
 140         "vm.paused file not created within 60 seconds.");
 141     }
 142     Files.delete(pauseFile);
 143   }
 144 
 145   private static int getUnixProcessId(Process unixProcess) throws Exception {
 146     Field pidField = unixProcess.getClass().getDeclaredField("pid");
 147     pidField.setAccessible(true);
 148     return (Integer)pidField.get(unixProcess);
 149   }
 150 }