add basic consts and functions for mbr

go.mod

@@ -0,0 +1,3 @@
+module github.com/byReqz/pt
+
+go 1.17

mbr/mbr.go

@@ -0,0 +1,74 @@
+package mbr
+import (
+	"fmt"
+	"os"
+)
+
+const (
+	MBRsize = 512
+
+	BootstrapCodeArea1Size = 218
+	BootstrapCodeArea1Offset = 0
+	BootstrapCodeArea2Size = 216
+	BootstrapCodeArea2Offset = 224
+	LegacyBootstrapCodeAreaOffset = 0
+	LegacyBootstrapCodeAreaSize = 446
+
+	DiskTimestampOffset = 218
+	DiskTimestampSize = 6
+	DiskTimeStampSecondsOffset = 221
+	DiskTimeStampSecondsSize = 1
+	DiskTimeStampMinutesOffset = 222
+	DiskTimeStampMinutesSize = 1
+	DiskTimeStampHoursOffset = 223
+	DiskTimeStampHoursSize = 1
+
+	PartitionEntrySize = 16
+	PartitionEntry1Offset = 446
+	PartitionEntry2Offset = 462
+	PartitionEntry3Offset = 478
+	PartitionEntry4Offset = 494
+
+	BootSignatureSize = 2
+	BootSignatureOffset = 510
+)
+
+type MBR struct {
+	BootstrapCode []byte
+	TimeStamp string
+	DiskSignature DiskSignature
+	Partitions []Partition
+	BootSignature int
+}
+
+type Partition struct {
+	Status string
+	Type string
+	Sectors int
+}
+
+type DiskSignature struct {
+	CopyProtected bool 
+	Signature int32
+}
+
+func DumpMBR(f *os.File) ([]byte, error) {
+	mbr := make([]byte, MBRsize)
+	_, err := f.Read(mbr)
+	if err != nil {
+		return mbr, err
+	}
+	return mbr, nil
+}
+
+func GetMBR(mbr []byte) error {
+	if len(mbr) < MBRsize {
+		return fmt.Errorf("input does not contain full mbr")
+	}
+
+	fmt.Println(mbr[446:462]) // part entry 1
+	fmt.Println(mbr[446]) // status  --  if 128 == bootable, if 0 == inactive
+	fmt.Println(mbr[450]) // partition type https://en.wikipedia.org/wiki/Partition_type
+
+	return nil
+}