Setting nixosVersion to something custom is useful for meaningful GRUB
menus and /nix/store paths, but actuallly changing it rebulids the
whole system path (because of `nixos-version` script and manual
pages). Also, changing it is not a particularly good idea because you
can then be differentitated from other NixOS users by a lot of
programs that read /etc/os-release.
This patch introduces an alternative option that does all you want
from nixosVersion, but rebuilds only the very top system level and
/etc while using your label in the names of system /nix/store paths,
GRUB and other boot loaders' menus, getty greetings and so on.
When using extlinux-conf-builder in a nix build using chroots, the
following error message could be seen:
/nix/store/XXX-extlinux-conf-builder.sh: line 121: cd: /nix/var/nix/profiles: No such file or directory
To avoid this, just skip the code path parsing /nix/var/nix/profiles
when $numGenerations (passed from the command line) is 0 (which is the
only legal value of $numGenerations in a nix build context).
Without a menu title, U-Boot's distro scripts just autoboot the first
entry by default.
When I initially wrote this, my board wasn't apparently running stock
U-Boot but had some local hacks saved in the U-Boot's environment
which made it always display the prompt.
When calling addEntry inside a subshell, the filesCopied array would
be updated only in the subshell's environment. This would only cause an
issue if no -g flag was passed to the script, causing no kernels
to be copied.
This module generates a /boot/extlinux/extlinux.conf bootloader
configuration file that is supported by e.g. U-Boot:
http://git.denx.de/?p=u-boot.git;a=blob;f=doc/README.distro;hb=refs/heads/master
With this, all ARM boards supported by U-Boot can be booted in a common
way (a single boot file generator, all boards booting via initrd like
x86) and with same boot menu functionality as GRUB has.
-- sample extlinux.conf file --
# Generated file, all changes will be lost on nixos-rebuild!
# Change this to e.g. nixos-42 to temporarily boot to an older configuration.
DEFAULT nixos-default
TIMEOUT 50
LABEL nixos-default
MENU LABEL NixOS - Default
LINUX ../nixos/n7vxfk60nb5h0mcbhkwwxhcz2q2nvxzv-linux-4.1.0-rc3-cpufreq-zImage
INITRD ../nixos/0ss2zs8sb6d1qn4gblxpwlxkfjsgs5f0-initrd-initrd
FDTDIR ../nixos/n7vxfk60nb5h0mcbhkwwxhcz2q2nvxzv-linux-4.1.0-rc3-cpufreq-dtbs
APPEND systemConfig=/nix/store/469qvr43ln8bfsnk5lzcz6m6jfcgdd4r-nixos-15.06.git.0b7a7a6M init=/nix/store/469qvr43ln8bfsnk5lzcz6m6jfcgdd4r-nixos-15.06.git.0b7a7a6M/init loglevel=8 console=ttyS0,115200n8 drm.debug=0xf
LABEL nixos-71
MENU LABEL NixOS - Configuration 71 (2015-05-17 21:32 - 15.06.git.0b7a7a6M)
LINUX ../nixos/n7vxfk60nb5h0mcbhkwwxhcz2q2nvxzv-linux-4.1.0-rc3-cpufreq-zImage
INITRD ../nixos/0ss2zs8sb6d1qn4gblxpwlxkfjsgs5f0-initrd-initrd
FDTDIR ../nixos/n7vxfk60nb5h0mcbhkwwxhcz2q2nvxzv-linux-4.1.0-rc3-cpufreq-dtbs
APPEND systemConfig=/nix/store/469qvr43ln8bfsnk5lzcz6m6jfcgdd4r-nixos-15.06.git.0b7a7a6M init=/nix/store/469qvr43ln8bfsnk5lzcz6m6jfcgdd4r-nixos-15.06.git.0b7a7a6M/init loglevel=8 console=ttyS0,115200n8 drm.debug=0xf
