On 03/15/2015 08:59 AM, Josh Triplett wrote:

This patch series introduces a new clone flag, CLONE_FD, which lets the caller
receive child process exit notification via a file descriptor rather than
SIGCHLD.  CLONE_FD makes it possible for libraries to safely launch and manage
child processes on behalf of their caller, *without* taking over process-wide
SIGCHLD handling (either via signal handler or signalfd).

Note that signalfd for SIGCHLD does not suffice here, because that still
receives notification for all child processes, and interferes with process-wide
signal handling.

It has been suggested (e.g.,
<https://sourceware.org/bugzilla/show_bug.cgi?id=15661#c3>) that you can
use the existing clone(2) without specifying SIGCHLD to create a new
process.  The resulting child process is not supposed to show up in
wait(2), only in a waitpid(2) (or similar) explicitly specifying the
PID.  Is this not the case?

-- 
Florian Weimer / Red Hat Product Security