Bug#950788: /usr/share/man/man5/sysctl.d.5.gz: sysctl.d.5 man page has confusing directory order

[Craig Small]

Hi Michael,
  I had a look at the systemd source code.  My aim is to make sure the
procps sysctl and the systemd sysctl behave the same way. The first problem
is we have a different order of things (/etc vs /run) so I looked at the
manual page first.

It looks like a lot of systemd programs have a standard set of directories
they check[1] which is different from what sysctl uses[2]. However, the
manual page implies there are two groups of directories and some override
others. From what I can see from the configuration file handling of
systemd[3] there is no "special" set and it is a matter of what directory
comes first. In other words, /usr/local/lib overrides /usr/lib (or /lib
depending) but the manual page doesn't say that.

I must admit I'm not too familiar with the systemd code, but that's how I
read it.

If that's the case, then I think there are three problems here:
* The systemd sysctl.d.6 man page is incorrect and really each previous
directory can override any directory after it (this bug #950788)
* procps sysctl config files shipped by Debian should be in /usr/lib
(procps bug #915797)
* procps sysctl should swap the order of /etc and /run so /etc comes first
and overrides things in /run like systemd sysctl does.

Does that seem right to you? I'll make the necessary changes in procps if
so.

 - Craig

1:
https://salsa.debian.org/systemd-team/systemd/blob/debian/master/src/basic/def.h#L44
2: https://salsa.debian.org/debian/procps/blob/master/sysctl.c#L624
3:
https://salsa.debian.org/systemd-team/systemd/blob/debian/master/src/basic/conf-files.c#L23

On Thu, 6 Feb 2020 at 23:15, Michael Biebl <biebl at debian.org> wrote:

> Hi Craig
>
> Am 06.02.20 um 12:31 schrieb Craig Small:
> > Package: systemd
> > Version: 244-3
> > Severity: minor
> > File: /usr/share/man/man5/sysctl.d.5.gz
> >
> > The sysctl.d.5 man page says this:
> >
> >       Configuration files are read from directories in /etc/, /run/,
> /usr/local/lib/, and /lib/, in order of precedence. Each configuration file
> in these configuration directories shall be named in the
> >       style of filename.conf. Files in /etc/ override files with the
> same name in /run/, /usr/local/lib/, and /lib/. Files in /run/ override
> files with the same name under /usr/.
> >
> > OK, so we have 4 directories.
> > Anything in /etc overrides anything in the other 3.
> >
> > But files in /run? They override.. /usr?
> > Is this supposed to mean /usr/local/lib?
> > Does that mean /run does NOT override files in /lib ?
> >
> > I think the man page used to say /usr/local/lib and /usr/lib and it was
> > (badly) saying both directories under /usr
> >
> > Maybe.. I'm not really sure what way to interpret this.
>
> I suppose this is a result of
>
> https://salsa.debian.org/systemd-team/systemd/blob/debian/master/debian/rules#L200
> doing some incorrect replacements.
>
> Replace /lib with /usr/lib and it will make more sense, I guess.
>
> I guess we have to fine-tune the sed expression.
>
>
>
>
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