Re: io_close proposal

[Roland McGrath]

I think any synchronization call definitely needs to be interruptible.  If
close can block, you should be able to take a signal during close and then
resume it just like with other io calls.  If you've lost the send right,
then you don't have to wait for the reply but you can't restart the close
operation.  If the RPC uses a move-send for the receiver right, then the
only solution I see is special-case stubs on both sides so that the EINTR
reply instead is a special format that returns the send right.  close will
have to put that new right (which probably has a different name) into the
dtable so that the fd can be used in the signal handler if the close didn't
complete.