internal/rosa: remove xz utils hack

This replaces all xz invocations with the native decompressor. This also significantly cleans up the Gentoo stage3 bootstrap path.

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

1 files changed, 104 insertions, 0 deletions

diff --git a/internal/rosa/gentoo.go b/internal/rosa/gentoo.go
new file mode 100644
index 00000000..a0a8e525
--- /dev/null
+++ b/internal/rosa/gentoo.go
@@ -0,0 +1,104 @@
+package rosa
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+
+	"hakurei.app/internal/pkg"
+)
+
+// gentooOverlay are symlinks on top of a Gentoo LLVM stage3 tarball for
+// compatibility with the Rosa OS stage0 distribution.
+type gentooOverlay struct{ stage3 pkg.Artifact }
+
+// Kind returns the hardcoded [pkg.Kind] value.
+func (a gentooOverlay) Kind() pkg.Kind { return kindGentooOverlay }
+
+// Params is a noop.
+func (a gentooOverlay) Params(*pkg.IContext) {}
+
+// IsExclusive returns false: Cure performs a trivial filesystem write.
+func (gentooOverlay) IsExclusive() bool { return false }
+
+// Inputs returns the underlying Gentoo stage3.
+func (a gentooOverlay) Inputs() []pkg.Artifact {
+	return []pkg.Artifact{a.stage3}
+}
+
+func init() {
+	pkg.Register(kindGentooOverlay, func(r *pkg.IRReader) pkg.Artifact {
+		a := gentooOverlay{r.Next()}
+		if _, ok := r.Finalise(); ok {
+			panic(pkg.ErrUnexpectedChecksum)
+		}
+		return a
+	})
+}
+
+// String returns a hardcoded name.
+func (a gentooOverlay) String() string { return "gentoo-overlay" }
+
+// Revision returns a hardcoded value incremented on layout changes.
+func (a gentooOverlay) Revision() uint64 { return 0 }
+
+// Cure installs the overlay.
+func (a gentooOverlay) Cure(f *pkg.FContext) (err error) {
+	pathname, _ := f.GetArtifact(a.stage3)
+	var stage3 *os.Root
+	if stage3, err = os.OpenRoot(pathname.String()); err != nil {
+		return err
+	}
+	defer func() {
+		closeErr := stage3.Close()
+		if err == nil {
+			err = closeErr
+		}
+	}()
+	fsys := stage3.FS()
+
+	system := f.GetWorkDir().Append("system")
+	bin := system.Append("bin")
+	if err = os.MkdirAll(bin.String(), 0700); err != nil {
+		return
+	}
+
+	linknames := []string{
+		"../../bin/sh",
+	}
+
+	var dents []os.DirEntry
+
+	const llvm = "usr/lib/llvm"
+	dents, err = fs.ReadDir(fsys, llvm)
+	if err != nil {
+		return
+	}
+	if len(dents) != 1 {
+		return errors.New("stage3 /" + llvm + " contains more than one entry")
+	}
+
+	llvmBin := filepath.Join(llvm, dents[0].Name(), "bin")
+	dents, err = fs.ReadDir(fsys, llvmBin)
+	if err != nil {
+		return
+	}
+	for _, dent := range dents {
+		linknames = append(linknames, filepath.Join(
+			"../..",
+			llvmBin,
+			dent.Name(),
+		))
+	}
+
+	for _, linkname := range linknames {
+		if err = os.Symlink(
+			linkname,
+			bin.Append(filepath.Base(linkname)).String(),
+		); err != nil {
+			return
+		}
+	}
+	return
+}