On Mon, Mar 23, 2015 at 02:12:34PM +0000, David Drysdale wrote:

On Mon, Mar 16, 2015 at 11:29 PM,  [off-list ref] wrote:

quoted

On Mon, Mar 16, 2015 at 03:14:14PM -0700, Thiago Macieira wrote:

quoted

On Monday 16 March 2015 14:44:20 Kees Cook wrote:

quoted

quoted

              O_CLOEXEC
                     Set  the  close-on-exec  flag on the new file
descriptor. See the description of the O_CLOEXEC flag in open(2)  for
reasons why this may be useful.

This begs the question: what happens when all CLONE_FD fds for a
process are closed? Will the parent get SIGCHLD instead, will it
auto-reap, or will it be un-wait-able (I assume not this...)

Depends on CLONE_AUTOREAP. If it's on, then no one gets SIGCHLD, no one can
wait() on it and the process autoreaps itself.

Minor nit: CLONE_AUTOREAP makes the process autoreap and nobody can wait
on it, but if you pass SIGCHLD or some other exit signal to clone then
you'll still get that signal.

Quick query: does CLONE_AUTOREAP also affect waiting for non-exit
events (i.e. WUNTRACED / WCONTINUED), by original parent and/or ptracer?

It shouldn't, no.  You can't wait on the process to exit (you'll get
-ECHLD after it wakes up), but you can wait on it to continue or
similar; none of the autoreap changes should affect that.

- Josh Triplett