RFR 8237858: PlainSocketImpl.socketAccept() handles EINTR incorrectly

[Daniel Fuchs]

Hi Vyom,

I have sent your proposed fix to our test system and observed no
regression. I agree your proposed changes seem to address the
issue adequately. However, I'd like to hear a second opinion on the
possible side effects of this fix, since NET_Timeout may be called
at many other places.

I see that Alan has commented on
https://bugs.openjdk.java.net/browse/JDK-8237858

It would be good to get his approval (or at least Michael McMahon's) 
before pushing.

best regards,

-- daniel

On 25/02/2020 16:36, Vyom Tewari26 wrote:
> Hi ,
> Please find the below fix for the 
> issue(https://bugs.openjdk.java.net/browse/JDK-8237858). In 
> "PlainSocketImpl_socketAccept" did not handle -1 timeout  properly.
> In case of -1 timeout, "PlainSocketImpl_socketAccept" calls 
> "NET_Timeout"  if it is interrupted by signal(EINTR) then in case of -1 
> timeout it returns immediately instead of looping again.
> Thanks,
> Vyom
> ##########################################################
> diff -r d6b968af8b65 src/java.base/linux/native/libnet/linux_close.c
> --- a/src/java.base/linux/native/libnet/linux_close.c    Mon Feb 24 
> 23:44:29 2020 -0500
> +++ b/src/java.base/linux/native/libnet/linux_close.c    Tue Feb 25 
> 19:06:11 2020 +0530
> @@ -437,12 +437,16 @@
>            * has expired return 0 (indicating timeout expired).
>            */
>           if (rv < 0 && errno == EINTR) {
> -            jlong newNanoTime = JVM_NanoTime(env, 0);
> -            nanoTimeout -= newNanoTime - prevNanoTime;
> -            if (nanoTimeout < NET_NSEC_PER_MSEC) {
> -                return 0;
> +            if(timeout > 0) {
> +                jlong newNanoTime = JVM_NanoTime(env, 0);
> +                nanoTimeout -= newNanoTime - prevNanoTime;
> +                if (nanoTimeout < NET_NSEC_PER_MSEC) {
> +                    return 0;
> +                }
> +                prevNanoTime = newNanoTime;
> +            } else {
> +                continue; // timeout is -1, so  loop again.
>               }
> -            prevNanoTime = newNanoTime;
>           } else {
>               return rv;
>           }
> 
> ############################################################
>