support UKI

2026-05-07 23:41:29 +02:00
parent e89b164581
commit 7a6310c93e
7 changed files with 230 additions and 109 deletions
@@ -3,11 +3,13 @@ package main
 import (
 	"archive/tar"
 	"bytes"
+	"debug/pe"
+	"fmt"
 	"io"
 	"log"
 	"os"
-
-	"novit.tech/direktil/local-server/pkg/utf16"
+	"path/filepath"
+	"time"
 )

 func rmTempFile(f *os.File) {
@@ -17,7 +19,124 @@ func rmTempFile(f *os.File) {
 	}
 }

-func buildBootTar(out io.Writer, ctx *renderContext) (err error) {
+func buildUki(out io.Writer, ctx *renderContext, uki bool, cmdline string) error {
+	if !uki {
+		return fmt.Errorf("buildUki only builds UKI")
+	}
+
+	const efiStubPath = "/usr/lib/systemd/boot/efi/linuxx64.efi.stub"
+
+	stub, err := pe.Open(efiStubPath)
+	if err != nil {
+		return fmt.Errorf("efi stub open: %w", err)
+	}
+
+	hdr := stub.OptionalHeader.(*pe.OptionalHeader64)
+	align := uint64(hdr.SectionAlignment)
+
+	var offset uint64
+	for _, s := range stub.Sections {
+		end := uint64(s.VirtualAddress) + uint64(s.VirtualSize)
+		if end > offset {
+			offset = end
+		}
+	}
+
+	offset += hdr.ImageBase
+
+	stub.Close()
+
+	// kernel
+	kernelPath, err := distFetch("kernels", ctx.Host.Kernel)
+	if err != nil {
+		return fmt.Errorf("fetch kernel: %w", err)
+	}
+
+	// temp dir
+	tempDir, err := os.MkdirTemp(os.TempDir(), "uki-")
+	if err != nil {
+		return fmt.Errorf("mkdir temp: %w", err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	// osrel
+	osrelPath := filepath.Join(tempDir, "osrel")
+	if err := os.WriteFile(osrelPath, fmt.Appendf(nil, "ID=direktil\nPRETTY_NAME='Direktil %s %s+0'\n", ctx.Host.Name,
+		time.Now().UTC().Format(time.DateTime)), 0o600); err != nil {
+		return fmt.Errorf("create osrel: %w", err)
+	}
+
+	// cmdline
+	cmdlinePath := filepath.Join(tempDir, "cmdline")
+	if err := os.WriteFile(cmdlinePath, append([]byte(cmdline), 0), 0o600); err != nil {
+		return fmt.Errorf("create cmdline: %w", err)
+	}
+
+	// initrd
+	initrdPath := filepath.Join(tempDir, "initrd")
+	if err := func() (err error) {
+		initrd, err := os.Create(initrdPath)
+		if err != nil {
+			return
+		}
+		defer initrd.Close()
+		return buildInitrd(initrd, ctx)
+	}(); err != nil {
+		return fmt.Errorf("create initrd: %w", err)
+	}
+
+	// assemble
+
+	args := make([]string, 0)
+	for _, i := range []struct {
+		section string
+		path    string
+	}{
+		{"osrel", osrelPath},
+		{"cmdline", cmdlinePath},
+		{"initrd", initrdPath},
+		{"linux", kernelPath},
+	} {
+		offset += align - offset%align
+		args = append(args,
+			"--add-section", "."+i.section+"="+i.path, "--change-section-vma", fmt.Sprintf(".%s=0x%x", i.section, offset))
+
+		stat, err := os.Stat(i.path)
+		if err != nil {
+			return fmt.Errorf("stat %s: %w", i.section, err)
+		}
+
+		offset += uint64(stat.Size())
+	}
+
+	ukiPath := filepath.Join(tempDir, "uki")
+	args = append(args, efiStubPath, ukiPath)
+
+	if err := run("objcopy", args...); err != nil {
+		return fmt.Errorf("objcopy: %w", err)
+	}
+
+	// read
+	ukiBytes, err := os.ReadFile(ukiPath)
+	if err != nil {
+		return fmt.Errorf("read uki: %w", err)
+	}
+
+	io.Copy(out, bytes.NewBuffer(ukiBytes))
+
+	// done
+	return nil
+}
+
+func buildBootTar(out io.Writer, ctx *renderContext, uki bool, cmdline string) (err error) {
+	if uki {
+		return buildUkiBootTar(out, ctx, cmdline)
+	} else {
+		return buildGrubBootTar(out, ctx)
+	}
+}
+
+func buildGrubBootTar(out io.Writer, ctx *renderContext) (err error) {
 	arch := tar.NewWriter(out)
 	defer arch.Close()

@@ -62,7 +181,7 @@ func buildBootTar(out io.Writer, ctx *renderContext) (err error) {
 	return nil
 }

-func buildBootEFITar(out io.Writer, ctx *renderContext) (err error) {
+func buildUkiBootTar(out io.Writer, ctx *renderContext, cmdline string) (err error) {
 	arch := tar.NewWriter(out)
 	defer arch.Close()

@@ -75,46 +194,14 @@ func buildBootEFITar(out io.Writer, ctx *renderContext) (err error) {
 		return
 	}

-	const (
-		prefix    = "EFI/dkl/"
-		efiPrefix = "\\EFI\\dkl\\"
-	)
-
-	// boot.csv
-	// -> annoyingly it's UTF-16...
-	bootCsvBytes := utf16.FromUTF8([]byte("" +
-		"current_kernel.efi,dkl current,initrd=" + efiPrefix + "current_initrd.img,Direktil current\n" +
-		"previous_kernel.efi,dkl previous,initrd=" + efiPrefix + "previous_initrd.img,Direktil previous\n"))
-
-	err = archAdd(prefix+"BOOT.CSV", []byte(bootCsvBytes))
+	// UKI
+	uki := new(bytes.Buffer)
+	err = buildUki(uki, ctx, true, cmdline)
 	if err != nil {
 		return
 	}

-	// kernel
-	kernelPath, err := distFetch("kernels", ctx.Host.Kernel)
-	if err != nil {
-		return
-	}
-
-	kernelBytes, err := os.ReadFile(kernelPath)
-	if err != nil {
-		return
-	}
-
-	err = archAdd(prefix+"current_kernel.efi", kernelBytes)
-	if err != nil {
-		return
-	}
-
-	// initrd
-	initrd := new(bytes.Buffer)
-	err = buildInitrd(initrd, ctx)
-	if err != nil {
-		return
-	}
-
-	err = archAdd(prefix+"current_initrd.img", initrd.Bytes())
+	err = archAdd("EFI/BOOT/BOOTX64.EFI", uki.Bytes())
 	if err != nil {
 		return
 	}