added update & uboot functions

resources/uboot.c

@@ -71,7 +71,7 @@ int main(int argc, char* argv[]) {
         data[1] = 0;
 
         // boot partition
-        data[2] = 2; // A=2, B=3
+        data[2] = 2; // A=1, B=2
     }
 
     // handle commands

system.go

@@ -65,6 +65,7 @@ func SystemDisableSSH() error {
 	return nil
 }
 
+// SystemShutdown start shutdown of system
 func SystemShutdown() error {
 	cmd := exec.Command(systemShutdown)
 	err := cmd.Run()
@@ -74,6 +75,7 @@ func SystemShutdown() error {
 	return nil
 }
 
+// SystemReboot start reboot of system
 func SystemReboot() error {
 	cmd := exec.Command(systemReboot)
 	err := cmd.Run()

update.go

@@ -0,0 +1,143 @@
+package alpine_builder
+
+import (
+	"compress/gzip"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"hash/crc32"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+)
+
+var ubootFile = "/uboot/uboot.dat"
+var ubootRemountRW = "mount -o remount,rw /uboot"
+var ubootRemountRO = "mount -o remount,ro /uboot"
+
+var rootPartitionA = "/dev/mmcblk0p1"
+var rootPartitionB = "/dev/mmcblk0p2"
+
+// loadUbootDat file to byte array
+func loadUbootDat() ([]byte, error) {
+	defaultData := make([]byte, 1024)
+	defaultData[0] = 1 // file version
+	defaultData[1] = 0 // boot counter
+	defaultData[2] = 1 // boot partition  A=1, B=2
+
+	data, err := ioutil.ReadFile(ubootFile)
+	if err != nil {
+		return defaultData, fmt.Errorf("failed to open file: %w", err)
+	}
+
+	// invalid dat file?
+	if len(data) < 1024 {
+		return defaultData, errors.New("invalid dat file -> fallback to defaults")
+	}
+
+	crc := binary.LittleEndian.Uint32(data[1020:])
+	bla := crc32.ChecksumIEEE(data[:1020])
+	if crc != bla {
+		return defaultData, errors.New("invalid crc -> fallback to defaults")
+	}
+
+	return data, nil
+}
+
+// saveUbootDat from byte array
+func saveUbootDat(data []byte) error {
+	// update crc
+	binary.LittleEndian.PutUint32(data[1020:],
+		crc32.ChecksumIEEE(data[:1020]))
+
+	// remount boot partition - writable
+	cmd := exec.Command(ubootRemountRW)
+	err := cmd.Run()
+	if err != nil {
+		return fmt.Errorf("failed to remount RW: %w", err)
+	}
+
+	// update uboot dat file
+	err = ioutil.WriteFile(ubootFile, data[:1024], os.ModePerm)
+	if err != nil {
+		return fmt.Errorf("failed write uboot dat: %w", err)
+	}
+
+	// remount boot partition - readonly
+	cmd = exec.Command(ubootRemountRO)
+	err = cmd.Run()
+	if err != nil {
+		return fmt.Errorf("failed to remount RO: %w", err)
+	}
+	return nil
+}
+
+// UBootResetCounter to 0
+func UBootResetCounter() error {
+	data, _ := loadUbootDat()
+	data[1] = 0
+	return saveUbootDat(data)
+}
+
+// UBootActive returns the active partition. A=1, B=2
+func UBootActive() uint8 {
+	data, _ := loadUbootDat()
+	return data[2]
+}
+
+// UBootSetActive sets the active partition. A=1, B=2
+func UBootSetActive(active uint8) error {
+	data, _ := loadUbootDat()
+	if active == 1 {
+		data[2] = 1
+	} else {
+		data[2] = 2
+	}
+	return saveUbootDat(data)
+}
+
+// UpdateSystem with the given image
+func UpdateSystem(image string) error {
+	data, _ := loadUbootDat()
+	rootPart := rootPartitionA
+	if data[2] == 1 {
+		rootPart = rootPartitionB
+	}
+
+	// open image file
+	inFile, err := os.Open(image)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer inFile.Close()
+
+	// decompress image
+	inDecompress, err := gzip.NewReader(inFile)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer inDecompress.Close()
+
+	// open root partition
+	out, err := os.OpenFile(rootPart,
+		os.O_WRONLY|os.O_TRUNC|os.O_SYNC, os.ModePerm)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer out.Close()
+
+	// write update
+	_, err = io.Copy(out, inDecompress)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// switch active partition
+	if data[2] == 1 {
+		return UBootSetActive(2)
+	} else {
+		return UBootSetActive(1)
+	}
+}

update_test.go

@@ -0,0 +1,179 @@
+package alpine_builder
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto/rand"
+	"encoding/binary"
+	"io"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func init() {
+	ubootFile = "test_uboot"
+	ubootRemountRW = "true"
+	ubootRemountRO = "true"
+	rootPartitionA = "test_rootA"
+	rootPartitionB = "test_rootB"
+}
+
+func TestLoadUbootDat(t *testing.T) {
+	ass := assert.New(t)
+
+	// file missing
+	data, err := loadUbootDat()
+	ass.EqualError(err, "failed to open file: open test_uboot: no such file or directory")
+	ass.Equal([]byte{1, 0, 1}, data[:3])
+
+	// file with invalid data
+	ass.NoError(ioutil.WriteFile(ubootFile, []byte{}, os.ModePerm))
+
+	data, err = loadUbootDat()
+	ass.EqualError(err, "invalid dat file -> fallback to defaults")
+	ass.Equal([]byte{1, 0, 1}, data[:3])
+
+	// file with invalid CRC
+	testData := make([]byte, 1024)
+	testData[0] = 1
+	testData[1] = 2
+	testData[2] = 2
+
+	ass.NoError(ioutil.WriteFile(ubootFile, testData, os.ModePerm))
+	data, err = loadUbootDat()
+	ass.EqualError(err, "invalid crc -> fallback to defaults")
+	ass.Equal([]byte{1, 0, 1}, data[:3])
+
+	// file with valid CRC
+	binary.LittleEndian.PutUint32(testData[1020:], 0x982E8B7A)
+
+	ass.NoError(ioutil.WriteFile(ubootFile, testData, os.ModePerm))
+	data, err = loadUbootDat()
+	ass.NoError(err)
+	ass.Equal(testData, data)
+
+	_ = os.Remove(ubootFile)
+}
+
+func TestSaveUbootDat(t *testing.T) {
+	ass := assert.New(t)
+
+	testData := make([]byte, 1024)
+	testData[0] = 1
+	testData[1] = 2
+	testData[2] = 2
+	ass.NoError(saveUbootDat(testData))
+
+	binary.LittleEndian.PutUint32(testData[1020:], 0x982E8B7A)
+
+	data, err := ioutil.ReadFile(ubootFile)
+	ass.NoError(err)
+	ass.Equal(testData, data)
+
+	_ = os.Remove(ubootFile)
+}
+
+func TestUBootResetCounter(t *testing.T) {
+	ass := assert.New(t)
+
+	// write test file
+	testData := make([]byte, 1024)
+	testData[0] = 1
+	testData[1] = 2
+	testData[2] = 2
+	binary.LittleEndian.PutUint32(testData[1020:], 0x982E8B7A)
+	ass.NoError(ioutil.WriteFile(ubootFile, testData, os.ModePerm))
+
+	ass.NoError(UBootResetCounter())
+
+	data, err := ioutil.ReadFile(ubootFile)
+	ass.NoError(err)
+	ass.Zero(data[1])
+
+	_ = os.Remove(ubootFile)
+}
+
+func TestUBootActive(t *testing.T) {
+	ass := assert.New(t)
+
+	// write test file
+	testData := make([]byte, 1024)
+	testData[0] = 1
+	testData[1] = 2
+	testData[2] = 2
+	binary.LittleEndian.PutUint32(testData[1020:], 0x982E8B7A)
+	ass.NoError(ioutil.WriteFile(ubootFile, testData, os.ModePerm))
+
+	ass.Equal(uint8(2), UBootActive())
+
+	_ = os.Remove(ubootFile)
+}
+
+func TestUBootSetActive(t *testing.T) {
+	ass := assert.New(t)
+
+	// write test file
+	testData := make([]byte, 1024)
+	testData[0] = 1
+	testData[1] = 2
+	testData[2] = 2
+	binary.LittleEndian.PutUint32(testData[1020:], 0x982E8B7A)
+	ass.NoError(ioutil.WriteFile(ubootFile, testData, os.ModePerm))
+
+	ass.NoError(UBootSetActive(1))
+
+	data, err := ioutil.ReadFile(ubootFile)
+	ass.NoError(err)
+	ass.Equal(uint8(1), data[2])
+
+	_ = os.Remove(ubootFile)
+}
+
+func TestUpdateSystem(t *testing.T) {
+	ass := assert.New(t)
+
+	// test uboot file
+	testData := make([]byte, 1024)
+	testData[0] = 1
+	testData[1] = 2
+	testData[2] = 2
+	binary.LittleEndian.PutUint32(testData[1020:], 0x982E8B7A)
+	ass.NoError(ioutil.WriteFile(ubootFile, testData, os.ModePerm))
+
+	// generate test image content
+	size := int64(1024 * 1024 * 5)
+	testImgData := make([]byte, size)
+	buffer := bytes.NewBuffer(testImgData)
+	_, err := io.CopyN(buffer, rand.Reader, size)
+	ass.NoError(err)
+
+	// write compressed image file
+	file, err := os.Create("test_image.gz")
+	ass.NoError(err)
+	gzipWriter := gzip.NewWriter(file)
+	_, err = gzipWriter.Write(testImgData)
+	ass.NoError(err)
+	ass.NoError(gzipWriter.Close())
+	ass.NoError(file.Close())
+
+	ass.NoError(ioutil.WriteFile(rootPartitionA, nil, os.ModePerm))
+	ass.NoError(UpdateSystem("test_image.gz"))
+
+	// check if image was written
+	data, err := ioutil.ReadFile(rootPartitionA)
+	ass.NoError(err)
+	ass.Equal(testImgData, data)
+
+	// check if uboot dat was updated
+	data, err = ioutil.ReadFile(ubootFile)
+	ass.NoError(err)
+	ass.Equal(uint8(1), data[2])
+
+	_ = os.Remove("test_image.gz")
+	_ = os.Remove(ubootFile)
+	_ = os.Remove(rootPartitionA)
+	_ = os.Remove(rootPartitionB)
+}