UKI builder

Author: sprat

Dockerfile

@@ -19,6 +19,7 @@ yamllint -v && yamllint -s -f colored .
 # =========================================================
 FROM golang:1.25.5-alpine AS imager-build
 SHELL ["/bin/ash", "-euxo", "pipefail", "-c"]
+RUN apk add --no-cache binutils systemd-efistub
 WORKDIR /go/src
 COPY imager/go.mod imager/go.sum ./
 RUN go mod download
@@ -34,11 +35,11 @@ FROM alpine:3.23.2 AS alpine-base
 
 # =========================================================
 FROM alpine-base AS imager
-# TODO: bundle objcopy (or use a golang lib) and systemd-efistub into the imager binary
-RUN apk add --no-cache binutils systemd-efistub
-COPY --from=imager-build /go/bin/imager /bin/imager
+# TODO: bundle systemd-efistub into the imager binary
+RUN apk add --no-cache systemd-efistub
+COPY --from=imager-build /go/bin/imager /usr/bin/imager
 WORKDIR /out
-ENTRYPOINT ["/bin/imager"]
+ENTRYPOINT ["/usr/bin/imager"]
 
 # =========================================================
 FROM alpine-base AS bootable-alpine-rootfs
@@ -97,7 +98,7 @@ if [ "$UCODE" != "none" ]; then apk add --no-cache "${UCODE}-ucode"; fi;
 # hadolint ignore=DL3006
 FROM imager AS test
 ARG FORMAT=efi
-RUN --mount=from=test-rootfs,target=/system /bin/imager --format "$FORMAT"
+RUN --mount=from=test-rootfs,target=/system imager --format "$FORMAT"
 
 # =========================================================
 # Generate a qemu image running our custom OS image

check_edit_pe.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/soyum2222/editPE"
+)
+
+func main() {
+    // open a exe file
+	file, err := os.ReadFile("..\\hello.exe")
+	if err != nil {
+		panic(err)
+	}
+
+	p := editPE.PE{}
+	p.Parse(file)
+
+	fmt.Println(len(p.ImageSectionHeaders))
+
+	// add a new section size is 100 byte
+	p.AddSection(".new", 100)
+
+	// save to disk
+	f, err := os.Create("..\\hello2.exe")
+	if err != nil {
+		panic(err)
+	}
+
+	f.Write(p.Raw)
+}

imager/cmdline.go

@@ -1,8 +1,17 @@
 package imager
 
-import "path/filepath"
+import (
+	"os"
+	"path/filepath"
+	"strings"
+)
 
-func (i Image) getCmdline() string {
-	// TODO: space-separated
-	return filepath.Join(i.RootFsDir, "boot", "cmdline")
+func (i Image) getCmdline() (string, error) {
+	path := filepath.Join(i.RootFsDir, "boot", "cmdline")
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return "", err
+	}
+	cmdline := strings.Replace(string(data), "\n", " ", -1)
+	return cmdline, nil
 }

imager/go.mod

@@ -5,6 +5,7 @@ go 1.25.0
 require (
 	github.com/cavaliergopher/cpio v1.0.1
 	github.com/otiai10/copy v1.14.1
+	github.com/soyum2222/editPE v0.0.0-20210624070249-c6fb60af2160
 	golang.org/x/sys v0.39.0
 )
 

imager/go.sum

@@ -4,6 +4,8 @@ github.com/otiai10/copy v1.14.1 h1:5/7E6qsUMBaH5AnQ0sSLzzTg1oTECmcCmT6lvF45Na8=
 github.com/otiai10/copy v1.14.1/go.mod h1:oQwrEDDOci3IM8dJF0d8+jnbfPDllW6vUjNc3DoZm9I=
 github.com/otiai10/mint v1.6.3 h1:87qsV/aw1F5as1eH1zS/yqHY85ANKVMgkDrf9rcxbQs=
 github.com/otiai10/mint v1.6.3/go.mod h1:MJm72SBthJjz8qhefc4z1PYEieWmy8Bku7CjcAqyUSM=
+github.com/soyum2222/editPE v0.0.0-20210624070249-c6fb60af2160 h1:4qLL5A+f9VE4R7H5viRlBI/ax/oxkLsphN2grtAaLFY=
+github.com/soyum2222/editPE v0.0.0-20210624070249-c6fb60af2160/go.mod h1:++uT61R9lWv7RD8YmtMk76ck2N9FYhRkgah3bmHkSBU=
 golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
 golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=

imager/initramfs.go

@@ -2,7 +2,6 @@ package imager
 
 import (
 	_ "embed"
-	"fmt"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -110,7 +109,8 @@ func addToCpioArchive(writer *cpio.Writer, path string, fileInfo fs.FileInfo, na
 	var err error
 	var data []byte
 
-	fmt.Printf("Adding %s\n", name)
+	// TODO: add to debug log
+	//fmt.Printf("Adding %s\n", name)
 
 	mode := fileInfo.Mode()
 

imager/kernel.go

@@ -3,7 +3,7 @@ package imager
 import "path/filepath"
 
 // Find the Linux kernel file in the root filesystem
-func (i Image) findKernel() (string, error) {
+func (i Image) findKernelPath() (string, error) {
 	pattern := filepath.Join(i.RootFsDir, "boot", "vmlinu*")
 	return findSingleFile(pattern)
 }

imager/os.go

@@ -0,0 +1,13 @@
+package imager
+
+import (
+	"os"
+	"path/filepath"
+)
+
+// Get the kernel release information
+func (i Image) getOSRelease() (string, error) {
+	path := filepath.Join(i.RootFsDir, "etc", "os-release")
+	data, err := os.ReadFile(path)
+	return string(data), err
+}

imager/pefile.go

@@ -5,75 +5,74 @@ import (
 	"path/filepath"
 
 	"github.com/sprat/claylinux/imager/efi"
+	"github.com/sprat/claylinux/imager/uki"
 )
 
 // Build the Unified Kernel Image
 func (i Image) buildUKI() (string, error) {
 	stubPath := efi.GetStubPath()
-	peFile, err := NewPEFile(stubPath)
+	stub, err := os.ReadFile(stubPath)
 	if err != nil {
 		return "", err
 	}
+	builder := uki.NewBuilder(stub)
 
 	// cmdline
-	cmdline := i.getCmdline()
-	err = peFile.AddSection(".cmdline", cmdline)
+	cmdline, err := i.getCmdline()
 	if err != nil {
 		return "", err
 	}
+	builder.AddSection(".cmdline", []byte(cmdline))
 
 	// initramfs
+	// TODO: build in memory?
 	initRamFsPath, err := i.buildInitRamFs()
 	if err != nil {
 		return "", err
 	}
-	err = peFile.AddSection(".initrd", initRamFsPath)
+	initRamFs, err := os.ReadFile(initRamFsPath)
 	if err != nil {
 		return "", err
 	}
+	builder.AddSection(".initrd", initRamFs)
 
 	// kernel release
 	kernelRelease, err := i.getKernelRelease()
 	if err != nil {
 		return "", err
 	}
-	kernelReleasePath := filepath.Join(i.BuildDir, "kernel-release")
-	os.WriteFile(kernelReleasePath, []byte(kernelRelease), 0644)
-	err = peFile.AddSection(".uname", kernelReleasePath)
-	if err != nil {
-		return "", err
-	}
+	builder.AddSection(".uname", []byte(kernelRelease))
 
 	// os release
-	osReleasePath := filepath.Join(i.RootFsDir, "etc", "os-release")
-	err = peFile.AddSection(".osrel", osReleasePath)
+	osRelease, err := i.getOSRelease()
 	if err != nil {
 		return "", err
 	}
+	builder.AddSection(".osrel", []byte(osRelease))
 
 	// TODO: include ucode
 	// ucodePath, err := findSingleFile(filepath.Join(i.RootFsDir, "boot", "*-ucode.img"))
-	// peFile.AddSection("".ucode", ucodePath)
-
-	// peFile.AddSection("".dtb", ...)
-	// peFile.AddSection("".splash", ...)
+	// builder.AddSection(".ucode", ucodePath)
+	// builder.AddSection(".dtb", ...)
+	// builder.AddSection(".splash", ...)
 
 	// kernel
 	// Should be the last section because everything after can be overwritten by in-place kernel decompression
-	kernelPath, err := i.findKernel()
+	kernelPath, err := i.findKernelPath()
 	if err != nil {
 		return "", err
 	}
-	err = peFile.AddSection(".linux", kernelPath)
+	kernel, err := os.ReadFile(kernelPath)
 	if err != nil {
 		return "", err
 	}
+	builder.AddSection(".linux", kernel)
 
-	// run objcopy
 	outputPath := filepath.Join(i.BuildDir, "claylinux.efi")
-	err = peFile.Finalize(outputPath)
+	err = builder.Write(outputPath)
 	if err != nil {
 		return "", err
 	}
+
 	return outputPath, nil
 }