On 2022-11-01, Arnaud Ferraris wrote: > Le 23/09/2022 à 19:22, Vagrant Cascadian a écrit : >> On 2022-09-23, Arnaud Ferraris wrote: >>> On Sat, 10 Sep 2022 10:18:39 -0700 Vagrant Cascadian >>> <vagr...@debian.org> wrote: >>>> On 2022-06-04, Jonas Smedegaard wrote: >>>>> Quoting Arnaud Ferraris (2022-06-04 16:39:03) >>>>>> Currently u-boot-menu makes use of a single configuration file >>>>>> one has to edit in order to change the default options. It could >>>>>> be useful to use config fragments containing only one (or more) >>>>>> variables, so that different packages could change different >>>>>> config options (for example, one fragment could modify the >>>>>> default cmdline, while another one could change the DTB folder). >>>>> >>>>> Thanks, that sounds like a useful feature indeed. >>>>> >>>>> Seems more sensible for me, however, to implement this using debconf. >>>>> >>>>> Otherwise, installation and removal of a package would need to trigger >>>>> u-boot-menu, and u-boot-menu would need to specially examine such >>>>> cofigfile snippets to skip snippets belonging to removed but not purged >>>>> packages. >>>> >>>> Well, you could implement configuration files snippets directory outside >>>> of /etc (e.g. /usr/share/u-boot-menu/snippet.d or something like that), >>>> which would avoid this problem. u-boot-menu could have a dpkg trigger >>>> that for when files in this directory change. >>> >>> I quite like this approach, thanks for the suggestion! >>> >>> Do you think allowing both /etc/u-boot-menu.d (aimed solely at >>> end-users) and /usr/share/u-boot-menu/conf.d (for other packages and/or >>> derivatives), with a dpkg trigger only on the latter, would make sense? >>> Or should we aim only for the /usr/share... approach? >> >> I think it's reasonable, though you'd have to encourage packages to >> *not* use /etc/u-boot-menu*.d, maybe documenting it in >> README.Debian... > > I added some notes about this in both the manpage and a (new) README.Debian > >> >> I could see a preference order being /etc/default/u-boot which is >> overidden by /usr/share/u-boot-menu/conf.d which is overridden by >> /etc/u-boot-menu.d (or /etc/u-boot-menu/conf.d ?). > > Yes, that makes the most sense to me (I also used > /etc/u-boot-menu/conf.d instead of /etc/u-boot-menu.d for consistency). > >> >> A fancy implementation might allow /etc to override /usr/share if the >> filenames match, but that might be more complicated than it's >> worth. Jonas knows I've fallen into that rabbit hole in packages of the >> ancient past... :) > > Hmm, I don't think that's worth the hassle as it would add *a lot* of > complexity for very little gain IMHO. > >> >> >>>> That seems a lot simpler than introducing the complexity of debconf >>>> generated configuration files... >>> >>> Indeed, so far my experiments with debconf for solving this matter have >>> been sub-optimal at best. >>> >>> I'll update my patch in the next few days and submit it asap. > > Updated patch attached, as always comments and suggestions are welcome :)
Looks good to me! Even uses dpkg-triggers properly. :)
Thanks!
I'll merge this and take a look at anything else that needs
poking at and maybe upload soon...
live well,
vagrant
> From 2949907b16bff2857cff0fb713967d264feb6567 Mon Sep 17 00:00:00 2001
> From: Arnaud Ferraris <aferra...@debian.org>
> Date: Tue, 1 Nov 2022 13:33:22 +0100
> Subject: [PATCH] u-boot-update: allow using config fragments
>
> In order to allow other packages and/or derivative distros to configure
> specific aspects of `u-boot-menu` it can be useful to allow using config
> fragments. This patch therefore implements loading config files from
> `/usr/share/u-boot-menu/conf.d` (to be used by other packages) and
> `/etc/u-boot-menu.d` (to be used by end-users, taking priority over
> files under the preceding location), overriding the values loaded from
> the default configuration file.
>
> This commit also adds a dpkg trigger so any modification of files under
> `/usr/share/u-boot-menu/conf.d` will result in `u-boot-update` being
> automatically run.
> ---
> debian/README.Debian | 32 ++++++++++++++++++++++++++++++++
> debian/u-boot-menu.postinst | 8 ++++++++
> debian/u-boot-menu.triggers | 1 +
> u-boot-update | 9 +++++++++
> u-boot-update.8 | 16 +++++++++++++++-
> 5 files changed, 65 insertions(+), 1 deletion(-)
> create mode 100644 debian/README.Debian
> create mode 100755 debian/u-boot-menu.postinst
> create mode 100644 debian/u-boot-menu.triggers
>
> diff --git a/debian/README.Debian b/debian/README.Debian
> new file mode 100644
> index 0000000..f502387
> --- /dev/null
> +++ b/debian/README.Debian
> @@ -0,0 +1,32 @@
> +Configuration files handling
> +============================
> +
> +Configuration files are read from the following locations, ordered by
> priority:
> +1. /etc/default/u-boot
> +2. /usr/share/u-boot-menu/conf.d/*.conf
> +3. /etc/u-boot-menu/conf.d/*.conf
> +
> +Each configuration file can contain one or more environment variable and is
> +sourced by u-boot-update. See u-boot-update(8) for more information about
> +allowed variables.
> +
> +Variables values can be overriden by highest-priority configuration files.
> For
> +example, if /etc/default/u-boot contains `U_BOOT_DEFAULT=l0` and there is a
> +file named /usr/share/u-boot-menu/conf.d/new-default.conf containing
> +`U_BOOT_DEFAULT=l0r`, then the menu entry labelled `l0r` will be set as the
> +default entry. Moreover, if there is a file named, for example,
> +/etc/u-boot-menu/conf.d/restore-default.conf containing `U_BOOT_DEFAULT=l1`,
> +then the default menu entry will be the one labelled `l1`.
> +
> +This allows flexible configuration management by allowing other packages (for
> +example, a support package for a specific device) to place configuration
> +fragment files under /usr/share/u-boot-menu/conf.d/ to override the default
> +values provided by u-boot-menu, while leaving an option for the end user to
> +get the final word by creating a configuration fragment file under
> +/etc/u-boot-menu/conf.d/.
> +
> +IMPORTANT: In order to avoid situations where the system might be rendered
> +unbootable by a package removed but not purged, other packages (or downstream
> +distributions) MUST NOT edit or modify files under /etc as those are meant
> for
> +use by end-users only. Instead, it is mandated for such packages to install
> +their config fragments ONLY under /usr/share/u-boot-menu/conf.d/.
> diff --git a/debian/u-boot-menu.postinst b/debian/u-boot-menu.postinst
> new file mode 100755
> index 0000000..abff2bf
> --- /dev/null
> +++ b/debian/u-boot-menu.postinst
> @@ -0,0 +1,8 @@
> +#!/bin/sh
> +
> +set -e
> +
> +if [ "$1" = "triggered" ]
> +then
> + /usr/sbin/u-boot-update
> +fi
> diff --git a/debian/u-boot-menu.triggers b/debian/u-boot-menu.triggers
> new file mode 100644
> index 0000000..ae73129
> --- /dev/null
> +++ b/debian/u-boot-menu.triggers
> @@ -0,0 +1 @@
> +interest-noawait /usr/share/u-boot-menu/conf.d
> diff --git a/u-boot-update b/u-boot-update
> index 69da211..8f3cd4f 100755
> --- a/u-boot-update
> +++ b/u-boot-update
> @@ -49,6 +49,15 @@ then
> . /etc/default/u-boot
> fi
>
> +# Reading config file fragments if they exist
> +for file in /usr/share/u-boot-menu/conf.d/*.conf
> /etc/u-boot-menu/conf.d/*.conf
> +do
> + if [ -e "${file}" ]
> + then
> + . "${file}"
> + fi
> +done
> +
> # Reading the os-release file
> if [ -e /etc/os-release ]
> then
> diff --git a/u-boot-update.8 b/u-boot-update.8
> index dfc3cd7..0c936fe 100644
> --- a/u-boot-update.8
> +++ b/u-boot-update.8
> @@ -9,7 +9,19 @@ u\-boot\-update \- program to generate u\-boot menu files
> .SH DESCRIPTION
> u\-boot\-update is a tool used to generate the menu files
> used by the U\-BOOT bootloader.
> -Options can be configured in /etc/default/u\-boot.
> +Options can be configured in /etc/default/u\-boot
> +or by adding configuration fragment files to /usr/share/u\-boot\-menu/conf.d/
> +(those take precedence over /etc/default/u\-boot) and/or to
> +/etc/u\-boot\-menu/conf.d/ (those take precedence over the 2 aforementioned
> +locations).
> +
> +.PP
> +
> +In order to avoid situations where the system might be rendered unbootable
> by a
> +package removal, other packages and downstream distributions MUST NOT edit or
> +modify files under /etc as those are meant for use by end\-users only.
> Instead,
> +it is mandated for such packages to install their config fragments ONLY under
> +/usr/share/u\-boot\-menu/conf.d/.
>
> .PP
>
> @@ -126,6 +138,8 @@ Default is 'initrd.img'.
>
> .SH FILES
> /etc/default/u-boot
> +/usr/share/u-boot-menu/conf.d/
> +/etc/u-boot-menu/conf.d/
>
> .SH HOMEPAGE
> More information about U\-BOOT
> --
> 2.35.1
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