RFR: JDK-8224642: Test sun/tools/jcmd/TestJcmdSanity.java fails: Bad file descriptor

[gary.adams at oracle.com]

The workaround below passed 1000 testruns on linux-x64-debug.

A more localized fix simply moves the stream reader out of the
try with resources, so only one close is applied to the underlying
socket. I'll run this test through 1000 testruns today.

Looking for a final review for this change.

diff --git a/src/jdk.jcmd/share/classes/sun/tools/jcmd/JCmd.java 
b/src/jdk.jcmd/share/classes/sun/tools/jcmd/JCmd.java
--- a/src/jdk.jcmd/share/classes/sun/tools/jcmd/JCmd.java
+++ b/src/jdk.jcmd/share/classes/sun/tools/jcmd/JCmd.java
@@ -122,8 +122,8 @@
              if (line.trim().equals("stop")) {
                  break;
              }
-            try (InputStream in = hvm.executeJCmd(line);
-                 InputStreamReader isr = new InputStreamReader(in, 
"UTF-8")) {
+            try (InputStream in = hvm.executeJCmd(line)) {
+                InputStreamReader isr = new InputStreamReader(in, "UTF-8");
                  // read to EOF and just print output
                  char c[] = new char[256];
                  int n;

On 6/17/19 3:23 PM, Gary Adams wrote:
> https://bugs.openjdk.java.net/browse/JDK-8224642
>
> I may have a handle on what is going wrong with the
> TestJcmdSanity test and the bad file descriptor.
>
> A change made in April 2019 placed the input stream and reader
> within the same try with resources block. This has the effect of 
> calling the
> SocketInputStream close method twice for each command processed.
>
> https://bugs.openjdk.java.net/browse/JDK-8222491
>   http://hg.openjdk.java.net/jdk/jdk/rev/4224f26b2e7f
>
> The last set of tests in the TestJcmdSanity test attempts to process ~100
> VM.version commands in a loop. Since the closes are handled
> when the objects are collected it may come at an inopportune time.
>
> I'm testing the fix below to ensure a second close becomes a noop.
> It may be better to revisit the earlier change that set up the double 
> close calls.
>
> diff --git 
> a/src/jdk.attach/linux/classes/sun/tools/attach/VirtualMachineImpl.java 
> b/src/jdk.attach/linux/classes/sun/tools/attach/VirtualMachineImpl.java
> --- 
> a/src/jdk.attach/linux/classes/sun/tools/attach/VirtualMachineImpl.java
> +++ 
> b/src/jdk.attach/linux/classes/sun/tools/attach/VirtualMachineImpl.java
> @@ -233,7 +233,7 @@
>       * InputStream for the socket connection to get target VM
>       */
>      private class SocketInputStream extends InputStream {
> -        int s;
> +        int s = -1;
>
>          public SocketInputStream(int s) {
>              this.s = s;
> @@ -261,7 +261,10 @@
>          }
>
>          public void close() throws IOException {
> +            if (s != -1) {
>              VirtualMachineImpl.close(s);
> +                s = -1;
> +            }
>          }
>      }