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* version 2 for more details (a copy is included in the LICENSE file that
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/*
* @test
* @bug 7162400
* @key regression
* @summary Regression test for attach issue where stale pid files in /tmp lead to connection issues
* @library /testlibrary
* @compile AttachWithStalePidFileTarget.java
* @run main AttachWithStalePidFile
*/
import com.oracle.java.testlibrary.*;
import com.sun.tools.attach.VirtualMachine;
import sun.tools.attach.HotSpotVirtualMachine;
import java.lang.reflect.Field;
import java.nio.file.*;
import java.nio.file.attribute.*;
import java.io.*;
public class AttachWithStalePidFile {
public static void main(String... args) throws Exception {
// this test is only valid on non-Windows platforms
if(Platform.isWindows()) {
System.out.println("This test is only valid on non-Windows platforms.");
return;
}
// Since there might be stale pid-files owned by different
// users on the system we may need to retry the test in case we
// are unable to remove the existing file.
int retries = 5;
while(!runTest() && --retries > 0);
if(retries == 0) {
throw new RuntimeException("Test failed after 5 retries. " +
"Remove any /tmp/.java_pid* files and retry.");
}
}
public static boolean runTest() throws Exception {
ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
"-XX:+UnlockDiagnosticVMOptions", "-XX:+PauseAtStartup", "AttachWithStalePidFileTarget");
Process target = pb.start();
Path pidFile = null;
try {
int pid = getUnixProcessId(target);
// create the stale .java_pid file. use hard-coded /tmp path as in th VM
pidFile = createJavaPidFile(pid);
if(pidFile == null) {
return false;
}
// wait for vm.paused file to be created and delete it once we find it.
waitForAndResumeVM(pid);
// unfortunately there's no reliable way to know the VM is ready to receive the
// attach request so we have to do an arbitrary sleep.
Thread.sleep(5000);
HotSpotVirtualMachine vm = (HotSpotVirtualMachine)VirtualMachine.attach(((Integer)pid).toString());
BufferedReader remoteDataReader = new BufferedReader(new InputStreamReader(vm.remoteDataDump()));
String line = null;
while((line = remoteDataReader.readLine()) != null);
vm.detach();
return true;
}
finally {
target.destroy();
target.waitFor();
if(pidFile != null && Files.exists(pidFile)) {
Files.delete(pidFile);
}
}
}
private static Path createJavaPidFile(int pid) throws Exception {
Path pidFile = Paths.get("/tmp/.java_pid" + pid);
if(Files.exists(pidFile)) {
try {
Files.delete(pidFile);
}
catch(FileSystemException e) {
if(e.getReason().equals("Operation not permitted")) {
System.out.println("Unable to remove exisiting stale PID file" + pidFile);
return null;
}
throw e;
}
}
return Files.createFile(pidFile,
PosixFilePermissions.asFileAttribute(PosixFilePermissions.fromString("rw-------")));
}
private static void waitForAndResumeVM(int pid) throws Exception {
Path pauseFile = Paths.get("vm.paused." + pid);
int retries = 60;
while(!Files.exists(pauseFile) && --retries > 0) {
Thread.sleep(1000);
}
if(retries == 0) {
throw new RuntimeException("Timeout waiting for VM to start. " +
"vm.paused file not created within 60 seconds.");
}
Files.delete(pauseFile);
}
private static int getUnixProcessId(Process unixProcess) throws Exception {
Field pidField = unixProcess.getClass().getDeclaredField("pid");
pidField.setAccessible(true);
return (Integer)pidField.get(unixProcess);
}
}