RFR 8237858: PlainSocketImpl.socketAccept() handles EINTR incorrectly

[Michael McMahon]

The change looks okay to me. Though the comment about the -1 case also 
applies
if timeout is 0. The behavior is still okay in that case, but the 
comment should acknowledge that,
however unlikely it is to occur.

- Michael.

On 10/03/2020 16:37, Daniel Fuchs wrote:
> 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;
>>           }
>>
>> ############################################################
>>
>