If the process in the new namespace dies very early
we have currently no chance to detect this.
The parent process will just die due to SIGPIPE
if it write to the fd used for synchronisation and
nobody will notice the real cause of the problem.
Install a SIGCHLD handler to detect the death.
Later
Quoting Richard Weinberger (rich...@nod.at):
> If the process in the new namespace dies very early
> we have currently no chance to detect this.
> The parent process will just die due to SIGPIPE
> if it write to the fd used for synchronisation and
> nobody will notice the real cause of the problem.
