Review Request for JMC-6621 - Handle event size 0

[Henrik Dafgård]

Hi Erik,

Using "jfr print" on a recording with a zero event size works as expected,
but running "jfr summary" on it doesn't produce a result. It seems to also
be stuck in an infinite loop.


Cheers,
Henrik Dafgård


On Thu, 31 Oct 2019 at 15:29, Erik Gahlin <erik.gahlin at oracle.com> wrote:

> Looks good.
>
> The JDK parser checks for a zero size, so the JMC parser should do the
> same,
>
> Erik
>
> > On 31 Oct 2019, at 15:05, Henrik Dafgård <hdafgard at gmail.com> wrote:
> >
> > Hi all,
> >
> > Should JMC attempt to parse a recording with an event size of 0 (this
> > should not be possible) it will currently enter an infinite loop. The
> patch
> > outlined below simply adds a check for size 0 and then throws a
> > CouldNotLoadRecordingException if that is the case.
> >
> > diff -r b153474a15a6
> >
> core/org.openjdk.jmc.flightrecorder/src/main/java/org/openjdk/jmc/flightrecorder/internal/parser/v1/ChunkLoaderV1.java
> > ---
> >
> a/core/org.openjdk.jmc.flightrecorder/src/main/java/org/openjdk/jmc/flightrecorder/internal/parser/v1/ChunkLoaderV1.java
> > Fri Oct 25 15:48:20 2019 +0200
> > +++
> >
> b/core/org.openjdk.jmc.flightrecorder/src/main/java/org/openjdk/jmc/flightrecorder/internal/parser/v1/ChunkLoaderV1.java
> > Thu Oct 31 15:00:27 2019 +0100
> > @@ -84,6 +84,9 @@
> >  input.seek(index);
> >  int size = input.readInt();
> >  long type = input.readLong();
> > + if (size == 0) {
> > + throw new CouldNotLoadRecordingException("Found event with invalid size
> > (0)");
> > + }
> >  if (type != CONSTANT_POOL_EVENT_TYPE && type !=
> > ChunkMetadata.METADATA_EVENT_TYPE) {
> >  manager.readEvent(type, input);
> >  }
> >
> >
> > Cheers,
> > Henrik Dafgård
>
>