RFR : 8038491: Improve synchronization in ZipFile.read()

[Xueming Shen]

Hi Sean,

It might be more explicit to check "if (zentry == 0)" here?

-Sherman

On 4/8/14 8:21 AM, Seán Coffey wrote:
> A recently reported bug shows a race condition is possible on the rem 
> == 0 check in ZipFile.read(byte b[], int off, int len). A bad check 
> can result in referencing a jzentry structure that might already be 
> freed and hence result in a SEGV. The fix is trivial and involves 
> moving the rem == 0 check into a synchronized block. The ZipFile API 
> itself is not thread safe so having mutiple threads operate on the 
> same ZipFileInputStream is something that should never be performed.
>
> webrev : http://cr.openjdk.java.net/~coffeys/webrev.8038491/webrev/
>
> regards,
> Sean.