nixos/grub: Insert required image modules for themes

With a limited testing of all packaged GRUB 2 themes (pkgs.nixos-grub2-theme)
this is tested to work.

Without this change, the theme loading will error out (waiting for a key press).

With this change, the theme loads and works as expected.

1 files changed, 25 insertions, 0 deletions

diff --git a/nixos/modules/system/boot/loader/grub/install-grub.pl b/nixos/modules/system/boot/loader/grub/install-grub.pl
index 93ad3f1ed706a..a84e374624d1b 100644
--- a/nixos/modules/system/boot/loader/grub/install-grub.pl
+++ b/nixos/modules/system/boot/loader/grub/install-grub.pl
@@ -385,6 +385,31 @@ rmtree("$bootPath/theme") or die "cannot clean up theme folder in $bootPath\n" i
 if ($theme) {
     # Copy theme
     rcopy($theme, "$bootPath/theme") or die "cannot copy $theme to $bootPath\n";
+
+    # Detect which modules will need to be loaded
+    my $with_png = 0;
+    my $with_jpeg = 0;
+
+    find({ wanted => sub {
+            if ($_ =~ /\.png$/i) {
+                $with_png = 1;
+            }
+            elsif ($_ =~ /\.jpe?g$/i) {
+                $with_jpeg = 1;
+            }
+    }, no_chdir => 1 }, $theme);
+
+    if ($with_png) {
+        $conf .= "
+            insmod png
+        "
+    }
+    if ($with_jpeg) {
+        $conf .= "
+            insmod jpeg
+        "
+    }
+
     $conf .= "
         # Sets theme.
         set theme=" . ($grubBoot->path eq "/" ? "" : $grubBoot->path) . "/theme/theme.txt