Bug#711853: insserv: Design bug: rcN.d unstable and not, maintainable

[Alessandro Vesely]

On Thu 25/Apr/2019 16:12:42 +0200 Dmitry Bogatov wrote:
> [2019-04-22 19:07] Alessandro Vesely <vesely at tana.it>
> 
>> The point is building every time from scratch, rigidly enjoining specs,
>> like it or lump it, versus an incremental, tolerant, minimal changes
>> operation.
> 
> What is the point of "incremental, tolerant, minimal changes operation"?


Just to allow a wider set of possibilities.


> C compiler always builds .o file from source file always afresh, and it
> reduces its complexity, and insserv(8) can be seen as compiler from
> content of /etc/init.d/, /etc/insserv/ and /etc/insserv.conf to
> /etc/rc[0-6].d


.o files are not quite editable.  To patch them, one needs so much careful
checking that it is not practical to do it.  There is no tool to support it.

And, you don't recompile every object and library every time.


> The only possible reason to attempt reusing existing content of
> /etc/rc[0-6].d is perfomance, and it does not apply.


I agree performance is not an issue.


> I argue, that isserv(8) is compiler, not build tool like make(1), since
> it is impossible to separate processing of any individual file from rest
> of them: /etc/init.d/, /etc/insserv/ and /etc/insserv.conf together
> are single input. It is possible to consider each /etc/rc[0-6].d as
> separate output, but it is useless.


Your latter paragraph condenses very well the point on which we disagree.

Unlike object files, /etc/rc?.d can be edited using ln, mv and rm.  It would
even be possible to place there a plain script or --why not?-- an executable.
No, I never did that and cannot imagine why on earth someone else would do it.
 But, in case, who am I to deny them the right to do so?

Put it another way, if I drop the (admittedly unrealistic) possibility to edit
rc?.d's by hand, I would have to conclude that that architecture is a relic
devoid of its functionality.  Do we maintain it for aesthetic reasons, like the
Colosseum?  I wouldn't know.  I like it, probably just because I've been using
it for so long.  I appreciate LSB comment convention as a clever evolution,
which helps ordering the links.  Preserving that somewhat baroque directory
structure, deprived of its flexibility merits, however, sounds fictional.


Best
Ale
--