[cups.development] [RFE] STR #2640: cups-polld doesn't notice if the cups it was logging stderr messages to goes away

[Jon Peatfield]

DO NOT REPLY TO THIS MESSAGE.  INSTEAD, POST ANY RESPONSES TO THE LINK BELOW.

[STR New]

Currently if cupsd is killed by something which means it doesn't clean up
child polld processes then the cups-pollds carry on running.

(actually in our case cupsd just died/crashed but it could have been
violently killed with the same effect).

Running strace/truss on the cups-polld shows it still trying to send
messages to stderr which reports EPIPE (here at least other OSs may be
different), but those errors arn't checked for.  It is also still sending
the update messages to the udp socket but those arn't easy to error check.

On starting a new cupsd it launches it's own cups-polld children so the
old ones arn't needed anyway.

I think it should be sagfe to add a check for ferror(stderr) and/or
foef(stderr) in the main loop and terminate if the parent has gone away.

This is (obviously) very very low priority 'cos it doesn't stop anything
from actually working, it would take a long time for the extra load to
become a problem and really cupsd shouldn't just die...

 -- Jon

Link: http://www.cups.org/str.php?L2640
Version:  -feature