test/hotspot/jtreg/runtime/appcds/jvmti/InstrumentationApp.java

*** 1,7 ****
  /*
!  * Copyright (c) 2014, 2017, 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.
--- 1,7 ----
  /*
!  * Copyright (c) 2014, 2019, 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.
*** 26,35 ****
--- 26,36 ----
  import java.lang.instrument.Instrumentation;
  import java.lang.instrument.UnmodifiableClassException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.io.File;
+ import java.io.FileWriter;
  import java.security.CodeSigner;
  import java.security.CodeSource;
  import java.security.ProtectionDomain;
  import sun.hotspot.WhiteBox;
  
*** 138,149 ****
--- 139,164 ----
              System.out.println("FINAL RESULT: All " + numTests + " test case(s) have passed!");
          }
      }
  
      static void waitAttach(String flagFile) throws Throwable {
+         // See InstrumentationTest.java for the hand-shake protocol.
          if (!flagFile.equals("noattach")) {
              File f = new File(flagFile);
+             try (FileWriter fw = new FileWriter(f)) {
+                 long pid = ProcessHandle.current().pid();
+                 System.out.println("my pid = " + pid);
+                 fw.write(Long.toString(pid));
+                 fw.write("\n");
+                 for (int i=0; i<10; i++) {
+                   // Parent process waits until we have written more than 100 bytes, so it won't
+                   // read a partial pid
+                   fw.write("==========");
+                 }
+                 fw.close();
+             }
+ 
              long start = System.currentTimeMillis();
              while (f.exists()) {
                  long elapsed = System.currentTimeMillis() - start;
                  System.out.println(".... (" + elapsed + ") waiting for deletion of " + f);
                  Thread.sleep(1000);