Bug#913247: Please provide a C implementation of /lib/init/init-d-script

[Mert Dirik]

On 11/22/18, Ian Jackson <ijackson at chiark.greenend.org.uk> wrote:
> Mert Dirik writes ("Bug#913247: Please provide a C implementation of
> /lib/init/init-d-script"):
>> I noticed the new snippet in the man page of experimental version uses
>> the
>> #! /usr/bin/env /lib/init/init-d-script
>> shebang, which doesn't work with systemd redirection.
>
> I don't know what `systemd redirection' is.  Why does it not work ?
> Can it be fixed ?
>

To sum it up, when /lib/lsb/init-functions is sourced from a script in
/etc/init.d, /lib/lsb/init-functions.d/40-systemd is also sourced and
the script is executed using a corresponding "systemctl ...." command
so that systemd can track the daemon. Relevant bug report is #826214.

The problem here is, 40-systemd uses the value of "$0" to figure out
whether the caller  was a script inside /etc/init.d/ and using
/lib/init/init-d-script breaks that. We partially fixed this in
init-d-script so that using the old "set "$0" "$@";
INIT_D_SCRIPT_SOURCED=true . /lib/init/init-d-script" snippet (as it
was in the /etc/init.d/skeleton) works correctly, but if
/lib/init/init-d-script (or /usr/bin/env) is used as shebang there is
no way to fix it inside init-d-script since dash scripts can't change
the value of $0.

I'm in the process of writing a longer opinion mail on
/lib/init/init-d-script but it's not finished yet.