internal/rosa: initramfs artifact

This constructs a single-program initramfs and populates /dev/null so the runtime does not throw if the kernel fails to set up console.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/images.go

@@ -0,0 +1,16 @@
+package rosa
+
+import "hakurei.app/internal/pkg"
+
+func (t Toolchain) newImageInitramfs() pkg.Artifact {
+	return t.New("initramfs", TNoToolchain, []pkg.Artifact{
+		t.Load(Zstd),
+		t.Load(Hakurei),
+	}, nil, nil, `
+cd "$(mktemp -d)"
+cp /system/libexec/hakurei/earlyinit init
+((find . | cpio -R 0:0 -o) && (cd / && echo dev/null | cpio -R 0:0 -o)) | \
+	zstd -19 > /work/initramfs.zst
+`)
+}
+func init() { artifactsF[ImageInitramfs] = Toolchain.newImageInitramfs }