when we get eof, stop the loop immidiately and do not
rely on the read to eventually return an error.
when convM2S() fails to decode the message, error out
and stop the loop. there is no point in continuing.
listensrv() used to override Srv.end() with its own handler
to free the malloc'd Srv structure and close the fd. this
makes it impossible to register your own cleanup handler.
instead, we introduce the private Srv.free() handler that
is used by listensrv to register its cleanup code. Srv.free()
is called once all the srv procs have been exited and all
requests on that srv have been responded to while Srv.end()
is called once all the procs exited the srv loop regardless
of the requests still being in flight.
using "interrupt" ctl message directly doesnt work when the
process is doing libthread channel operations (threadrendezvous)
as it will just repeat a interrupted rendezvous(). threadint()
handles this for us.
file->parent can be nil when the file has been previously removed.
removefile() deals with this, so skip the permission check in
that case and let removefile() error out.
the code was correct. erealloc9p() terminates the process
on error, but the code was handling realloc() error explicitely
and responded the request with Enomem error.
use the Srv.end callback for freeing the srv and closing the
file descriptor of a connection. this makes sure we wont free
the srv while there are still outstanding requests that would
access the srv when doing the respond() call.
in multithreaded programs, we have to wait until all outstanding
requests have been responded before closing down the srv.
dont make write errors sysfatal(), only print them. in case if
listensrv() is used we dont want to exit the process in respond()
called by some worker thread.
make sure Tversion is only handled when there are no outstanding
requests and make sure message size is sane.
