Add support for /etc/dhcpcd/hooks/

[perkelix]

In its current form, dhcpcd ships its configured hooks in --libexecdir and its extra sample hooks in /usr/share/dhcpcd/hooks/.

It would be desirable for dhcpcd to also source e.g. /etc/dhcpcd/hooks/ for administrator-added scripts.

At the same time, it would be desirable for BUILDING.md or README.md to document the existence of EGHOOKSCRIPTS and explain the difference with HOOKSCRIPTS.

[rsmarples]

Administrator added scripts are /etc/dhcpcd.enter-hook and /etc/dhcpcd.exit-hook.
If the admin wants to source a directory inside these scripts they are more than welcome to.

[rsmarples]

At the same time, it would be desirable for BUILDING.md or README.md to document the existence of EGHOOKSCRIPTS and explain the difference with HOOKSCRIPTS.

BUILDING.md already has this:

Not all the hooks in dhcpcd-hooks are installed by default.
By default we install 01-test, 20-resolv.confand 30-hostname.
The other hooks, 10-wpa_supplicant, 15-timezone and 29-lookup-hostname
are installed to $(datadir)/dhcpcd/hooks by default and need to be
copied to $(libexecdir)/dhcpcd-hooks for use.

I think it's already explained there?

[perkelix]

That still doesn't tell us which one is which or what configure keys to use for either case.

[rsmarples]

datadir defaults to /usr/share and libexecdir defaults to /libexec. I used the gnu configure variables here to make life easy I thought?

[perkelix]

The variables' name remains opaque. It leaves downstream guessing.

--with-hooks="timesyncd.conf"

...apparently results in:

HOOKSCRIPTS = 50-timesyncd.conf

I emphasize apparently because it I wouldn't have known without experimenting with the configure options, which is how –among other thigns– I found out that --with-hooks expects filenames without the numeric prefix.

What option would populate the EGHOOKSCRIPTS line and what it's used for remains opaque.

"We install this here and that there" doesn't tell us much. i.e. BUILDING.md needs to show an example for both cases:

Not all the hooks in dhcpcd-hooks are installed by default. By default, we install 01-test, 20-resolv.confand 30-hostname into $(libexecdir)/dhcpcd-hooks for use. The other hooks, 10-wpa_supplicant, 15-timezone and 29-lookup-hostname are installed as examples into $(datadir)/dhcpcd/hooks by default. The configure program attempts to find hooks for daemons you have installed. These will appear on the HOOKSCRIPTS line in configure's output, along with any hook added using the --with-hooks option without the numeric prefix e.g. ./configure -with-hook=ntp.conf

This leaves EGHOOKSCRIPTS undocumented.

[perkelix]

Looking into the source code for dhcpcd-run-hooks, I notice:

for hook in \
    @SYSCONFDIR@/dhcpcd.enter-hook \
    @HOOKDIR@/* \
    @SYSCONFDIR@/dhcpcd.exit-hook
do

Could this possibly be converted to:

for hook in \
    @SYSCONFDIR@/dhcpcd/enter-hooks.d/* \
    @HOOKDIR@/* \
    @SYSCONFDIR@/dhcpcd/exit-hooks.d/*
do

...for upcoming releases, @rsmarples? This would probably accomplish what was requested at Debian.

[rsmarples]

Sorry for not doing anything on this for a while. If we're going to have an /etc/dhcpcd to avoid putting many things directly into /etc then we should move the config layout as well. Maybe something like this?

/etc/dhcpcd
    ./dhcpcd.conf
    ./enter-hook
    ./enter-hooks.d/
    ./exit-hooks.d/
    ./exit-hook

/etc/dhcpcd could then be a symlink to /var/chroot/dhcpcd/etc/dhcpcd if we ever need dhcpcd.conf inside the chroot