Falling back to unversioned `/etc/fonts/conf.d` when versioned one does not exist
is problematic since it only occurs on non-NixOS systems and those are likely
to have a different version of fontconfig. When those versions use incompatible
elements in the config, apps using fontconfig will crash.
Instead, we are now falling back to the in-package `fonts.conf` file that loads
both the versioned global `conf.d` directory and the in-package `conf.d` since using
upstream settings on non-NixOS is preferable to not being able to use apps there.
In fact, we would not even need to link `fonts.conf`, as the in-package `fonts.conf`
will be always used unless someone creates the global one manually (the option is still
retained if one wants to write a custom NixOS module and to avoid unnecessary stat call on NixOS).
Additionally, since the `fonts.conf` will always load `conf.d` from the package, we no longer
need to install them to sytem `/etc` in the module. This needed some mucking with `50-user.conf`
which disables configs in user directories (a good thing IMO, NixOS module will turn it back on)
but otherwise, it is cleaner. The files are still prioritized by their name, regardless of their location.
See https://github.com/NixOS/nixpkgs/pull/73795#issuecomment-634370125 for more information.
Per upstream:
> libvirtd-tcp.socket - the unit file corresponding to the TCP 16509
> port for non-TLS remote access. This socket should not be configured
> to start on boot until the administrator has configured a suitable
> authentication mechanism.
Fixes error
Can't use an undefined value as an ARRAY reference at /nix/store/...-install-grub.pl line 642, <FILE> line 5.
with `/boot/grub/state` being:
```
grub
2.04
no
/dev/sda
/boot
```
I am not sure where the trailing empty line can come from; the script does not
seem to write it. In any case, now we handle that situation as well.
Further, ensure that `extraGrubInstallArgs` defaults to the empty array
if its key is not present in the `jsonState`.
For example, turns the error
cannot copy /nix/store/g24xsmmsz46hzi6whv7qwwn17myn3jfq-grub-2.04/share/grub/unicode.pf2 to /boot
into the more useful
cannot copy /nix/store/g24xsmmsz46hzi6whv7qwwn17myn3jfq-grub-2.04/share/grub/unicode.pf2 to /boot: Read-only file system
Useful for when you need to build grub modules into your grub kernel
to get a working boot, as shown in the added example.
To store this new value, we switch to more structural JSON approach.
Using one line per value to store in `/boot/grub/state` gets really messy when
the values are arrays, or even worse, can contain newlines (escaping would be
needed). Further, removing a value from the file would get extra messy
(empty lines we'd have to keep for backwards compatibility).
Thus, from now on we use JSON to store all values we'll need in the future.
Without this, systemd-boot does not add an EFI boot entry for itself.
The reason it worked before this fix is because it would fall back to
the default installed \EFI\BOOT\BOOTX64.EFI
`sslCACert` was used for trust store of client and server certificates. Since `smtpd_tls_ask_ccert` defaults to no the setup of `smtpd_tls_CApath` was removed.
>By default (see smtpd_tls_ask_ccert), client certificates are not requested, and smtpd_tls_CApath should remain empty.
see http://www.postfix.org/postconf.5.html#smtpd_tls_CAfile
boot.loader.grub.device` was hardcoded to `bootDevice`, which is
wrong, because that's the device for `/`, and with `useBootLoader`
the boot loader is not on that device.
This bug probably came into existence because of bad naming;
`virtualisation.bootDevice` has description
"The disk to be used for the root filesystem", which is very confusing;
it should be `.rootDevice` then!
Unfortunately, the description is right and the attribute name is wrong,
so it is not easy to change this without deprecation.
This commit ensures that even if you use `useBootLoader` and
`diskInterface == "scsi"`, the created VM can boot through, and can run
`nixos-rebuild afterwards.
It also adds extra commentary to explain what's going on in this module
in general in relation to `useBootLoader`.
