From 23ec82f4ec576efb8b2783b56dcaba99f28998d7 Mon Sep 17 00:00:00 2001
From: Melora Hugues <dev@faercol.me>
Date: Sat, 16 Sep 2023 17:00:46 +0200
Subject: [PATCH] Add support for hard drive nodes

---
 base.go           |   2 +
 go.mod            |   5 ++-
 go.sum            |   2 +
 harddrive.go      | 105 ++++++++++++++++++++++++++++++++++++++++++++++
 harddrive_test.go |  18 ++++++++
 parser.go         |   1 +
 6 files changed, 132 insertions(+), 1 deletion(-)
 create mode 100644 harddrive.go
 create mode 100644 harddrive_test.go

diff --git a/base.go b/base.go
index 239da4c..5b8e5b5 100644
--- a/base.go
+++ b/base.go
@@ -30,6 +30,8 @@ const EndOfEntireDevicePath DeviceNodeSubType = 0xFF
 
 const ACPISubType DeviceNodeSubType = 1
 
+const HardDriveSubType DeviceNodeSubType = 1
+
 type DevicePathNode interface {
 	Type() DeviceNodeType
 	SubType() DeviceNodeSubType
diff --git a/go.mod b/go.mod
index 0d690c3..6deb360 100644
--- a/go.mod
+++ b/go.mod
@@ -2,7 +2,10 @@ module git.faercol.me/faercol/devicepath
 
 go 1.20
 
-require github.com/stretchr/testify v1.8.4
+require (
+	github.com/google/uuid v1.3.1
+	github.com/stretchr/testify v1.8.4
+)
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
diff --git a/go.sum b/go.sum
index fa4b6e6..e70524c 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,7 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/google/uuid v1.3.1 h1:KjJaJ9iWZ3jOFZIf1Lqf4laDRCasjl0BCmnEGxkdLb4=
+github.com/google/uuid v1.3.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
diff --git a/harddrive.go b/harddrive.go
new file mode 100644
index 0000000..f2aa503
--- /dev/null
+++ b/harddrive.go
@@ -0,0 +1,105 @@
+package devicepath
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/google/uuid"
+)
+
+const (
+	hdLength uint16 = 2
+	hdPrefix string = "HD"
+)
+
+func signatureTypeToStr(val uint8) string {
+	switch val {
+	case 1:
+		return "MBR"
+	default:
+		return "GPT"
+	}
+}
+
+func formatSignature(signature [16]byte, signatureType uint8) string {
+	switch signatureType {
+	case 1: // MBR
+		return fmt.Sprintf("%x", signature[:4]) // only stored on the first 4 bytes
+	default: // default is GPT
+		parsedUID, _ := uuid.FromBytes(signature[:])
+		return parsedUID.String()
+	}
+}
+
+type HardDriveDevicePath struct {
+	partitionNumber    uint32
+	partitionStart     uint64
+	partitionSize      uint64
+	partitionSignature [16]byte
+	// partitionFormat    uint8
+	signatureType uint8
+}
+
+func (hp *HardDriveDevicePath) Type() DeviceNodeType {
+	return MediaDevicePath
+}
+
+func (hp *HardDriveDevicePath) SubType() DeviceNodeSubType {
+	return HardDriveSubType
+}
+
+func (hp *HardDriveDevicePath) String() string {
+	return fmt.Sprintf("%s(%d,%s,%s,0x%x,0x%x)", hdPrefix, hp.partitionNumber, signatureTypeToStr(hp.signatureType), formatSignature(hp.partitionSignature, hp.signatureType), hp.partitionStart, hp.partitionSize)
+}
+
+func (hp *HardDriveDevicePath) Bytes() []byte {
+	return nil
+}
+
+func (hp *HardDriveDevicePath) ParseString(raw string) error {
+	if !checkStringFormat(raw, hdPrefix, -1) {
+		return ErrMalformedString
+	}
+	args := strings.Split(raw[len(hdPrefix)+1:len(raw)-1], ",")
+	if len(args) != 5 {
+		return errors.New("unexpected number of arguments")
+	}
+
+	if partNumber, err := strconv.ParseUint(args[0], 10, 32); err != nil {
+		return err
+	} else {
+		hp.partitionNumber = uint32(partNumber)
+	}
+
+	switch args[1] {
+	case "MBR":
+		return errors.New("MBR partitions not yet supported")
+	default:
+		hp.signatureType = 2
+	}
+
+	if uid, err := uuid.Parse(args[2]); err != nil {
+		return err
+	} else {
+		if dat, err := uid.MarshalBinary(); err != nil {
+			return err
+		} else {
+			hp.partitionSignature = [16]byte(dat)
+		}
+	}
+
+	if start, err := strconv.ParseUint(args[3], 0, 64); err != nil {
+		return err
+	} else {
+		hp.partitionStart = start
+	}
+
+	if size, err := strconv.ParseUint(args[4], 0, 64); err != nil {
+		return err
+	} else {
+		hp.partitionSize = size
+	}
+	return nil
+}
diff --git a/harddrive_test.go b/harddrive_test.go
new file mode 100644
index 0000000..4f2bc39
--- /dev/null
+++ b/harddrive_test.go
@@ -0,0 +1,18 @@
+package devicepath_test
+
+import (
+	"testing"
+
+	"git.faercol.me/faercol/devicepath"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestHDParseString(t *testing.T) {
+	t.Run("GPT", func(t *testing.T) {
+		expected := "HD(1,GPT,16f06d01-50da-6544-86bd-f3457f980086,0x1000,0x96000)"
+		var dev devicepath.HardDriveDevicePath
+		require.NoError(t, dev.ParseString(expected))
+		assert.Equal(t, expected, dev.String())
+	})
+}
diff --git a/parser.go b/parser.go
index 1a92ab5..c7ac1c7 100644
--- a/parser.go
+++ b/parser.go
@@ -34,6 +34,7 @@ var prefixTypeAssociation = map[string]nodeGenerator{
 	sataPrefix:    func() DevicePathNode { return &SataDevicePath{} },
 	pciPrefix:     func() DevicePathNode { return &PCIDevicePath{} },
 	pciRootPrefix: func() DevicePathNode { return &PCIRootDevicePath{} },
+	hdPrefix:      func() DevicePathNode { return &HardDriveDevicePath{} },
 }
 
 func Parsenode(raw string) (DevicePathNode, error) {