> On Mon, 20.12.10 14:26, Scott James Remnant (
scott@netsplit.com) wrote:
>
>> > This patch adds a simple flag for each process that marks it as an
>> > "anchor" process for all its children and grandchildren. If a child of
>> > such an anchor dies all its children will not be reparented to init, but
>> > instead to this anchor, escaping this anchor process is not possible. A
>> > task with this flag set hence acts is little "sub-init".
>> >
>> Why can't you simply begin a new pid namespace with the session
>> manager or other process supervisor? That way the session
>> manager/process supervisor is for all intents and purposes an init
>> daemon, so shouldn't be surprised about getting SIGCHLD.
>
> PID namespaces primarily provide an independent PID numbering scheme for
> a subset of processes, i.e. so that identical may PIDs refer to different
> processes depending on the namespace they are running in. As a side
> effect this also provides init-like behaviour for processes that aren't
> the original PID 1 of the operating system. For systemd we are only
> interested in this side effect, but are not interested at all in the
> renumbering of processes, and in fact would even really dislike if it
> happened. That's why PR_SET_ANCHOR is useful: it gives us init-like
> behaviour without renaming all processes.
>
