RFR: 8039173 Propagate errors from Diagnostic Commands as exceptions in the attach framework

[Staffan Larsen]

Thanks for finding these bugs, Ivan!

I have updated the webrev at: http://cr.openjdk.java.net/~sla/8039173/webrev.01/, and I have also included the diff below.

The updated webrev also has some changes in the javadoc for VirtualMachine to clarify that some methods can now throw AttachOperationFailedException.

Thanks,
/Staffan


diff --git a/src/share/classes/sun/tools/attach/HotSpotVirtualMachine.java b/src/share/classes/sun/tools/attach/HotSpotVirtualMachine.java
--- a/src/share/classes/sun/tools/attach/HotSpotVirtualMachine.java
+++ b/src/share/classes/sun/tools/attach/HotSpotVirtualMachine.java
@@ -266,18 +266,21 @@
      */
     String getErrorMessage(InputStream sis, int maxlen) throws IOException {
         byte b[] = new byte[maxlen];
-        int n, off = 0, len = b.length;
+        int n, off = 0, len = maxlen;
         do {
             n = sis.read(b, off, len);
+            if (n == -1) {
+                break;
+            }
             off += n;
             len -= n;
-        } while (n >= 0 && off < b.length);
+        } while (off < maxlen);

         String message = null;
         if (off > 0) {
             message = new String(b, 0, off, "UTF-8");
         }
-        if (off == b.length && message != null) {
+        if (off > b.length && message != null) {
             message += " ...";
         }
         return message;


On 4 apr 2014, at 11:18, Ivan Gerasimov <ivan.gerasimov at oracle.com> wrote:

> Hi Staffan!
> 
> I think there is a couple of minor bugs in getErrorMessage(InputStream sis, int maxlen).
> 
> 1) If maxlen is exactly the size of the message to read, the function will add an ellipsis, even though the message isn't truncated,
> 2) If maxlen is greater than needed, then sis.read(b, off, len) at the line #271 will eventually return -1, and it will cause the message to lose its last character.
> 
> Sincerely yours,
> Ivan
>