On Wed, 10 Dec 2025 15:45:35 GMT, Alan Bateman <[email protected]> wrote:
>> Hi,
>>
>> This change updates the use of NET_ThrowNew in Inet4AddressImpl.c +
>> Inet6AddressImpl.c (unix).
>> Currently EINTR is incorrectly handled in NET_ThrowNew to throw
>> InterruptedIOException.
>>
>> The only possible places in these files where EINTR can be returned is in
>> the sendto() calls
>> for ping4() and ping6() used by the InetAddress.isReachable() API.
>>
>> The change checks for EINTR returned from those calls and restarts the
>> sendto()
>> if the timeout allows it. If EINTR is detected by NET_ThrowNew it is thrown
>> as an ordinary
>> SocketException, but this should not happen.
>>
>> The fix is only partially tested as it is difficult to make sendto() return
>> EINTR in practice, but
>> I added a unit test for the new native function that checks if the timeout
>> has expired.
>>
>> Thanks,
>> Michael
>
> src/java.base/unix/native/libnet/Inet4AddressImpl.c line 401:
>
>> 399: icmp->icmp_cksum = in_cksum((u_short *)icmp, plen);
>> 400: // send it
>> 401: while (1) {
>
> Are you sure it is possible for sendto to block indefinitely here? Maybe
> EINTR is possible but I think it would be okay to retry unconditionally,
> meaning I don't think timerMillisExpired is needed here.
>
> Are you sure that we restart for the other blocking syscalls (poll, recvfrom,
> ...) in these methods?
Oops. Didn't notice I had left the other calls out. Will add them now.
As for sendto() it's a lot less likely to block and I doubt it can block
indefinitely, but I imagine it can block if socket buffer is full. I don't have
a strong preference. If EINTR can be returned maybe it should be handled the
same way?
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/28750#discussion_r2607281100
