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package core
import (
"bufio"
"bytes"
"encoding/binary"
"encoding/json"
"fmt"
bolt "go.etcd.io/bbolt"
"io"
"os"
)
type Header struct {
MagicNumber int
Signature string
FilesystemSize int
FilesystemUnit int
TableSize int
TableUnit int
}
type Node struct {
BlockStart int
BlockEnd int
BlockSum string
PrevNodeSum string
}
func (n *Node) GetHash() (string, error) {
return calculateStringHash(fmt.Sprintf("%d%d%s%s", n.BlockStart, n.BlockEnd, n.BlockSum, n.PrevNodeSum))
}
func parseUnitSpec(size []byte) int {
switch size[0] {
case 0:
return 1
case 1:
return 1000
case 2:
return 1000000
case 3:
return 1000000000
case 4:
return 1000000000000
case 5:
return 1000000000000000
default:
return -1
}
}
func ReadHeader(partition string) (Header, error) {
_, exist := os.Stat(partition)
if os.IsNotExist(exist) {
return Header{}, fmt.Errorf("Cannot find partition %s", partition)
}
part, err := os.Open(partition)
if err != nil {
return Header{}, err
}
defer part.Close()
header := Header{}
reader := bufio.NewReader(part)
MagicNumber := make([]byte, 2)
UntrustedHash := make([]byte, 100)
TrustedHash := make([]byte, 88)
FilesystemSize := make([]byte, 4)
FilesystemUnit := make([]byte, 1)
TableSize := make([]byte, 4)
TableUnit := make([]byte, 1)
_, err = reader.Read(MagicNumber)
MagicNum := binary.BigEndian.Uint16(MagicNumber)
if MagicNum != 0xACAB { // The Silliest of magic numbers
return Header{}, err
}
header.MagicNumber = int(MagicNum)
_, err = reader.Read(UntrustedHash)
if err != nil {
return Header{}, err
}
_, err = reader.Read(TrustedHash)
if err != nil {
return Header{}, err
}
_, err = reader.Read(FilesystemSize)
if err != nil {
return Header{}, err
}
_, err = reader.Read(FilesystemUnit)
if err != nil {
return Header{}, err
}
_, err = reader.Read(TableSize)
if err != nil {
return Header{}, err
}
_, err = reader.Read(TableUnit)
if err != nil {
return Header{}, err
}
header.Signature = fmt.Sprintf("untrusted comment: fsverify\n%s\ntrusted comment: fsverify\n%s\n", string(UntrustedHash), string(TrustedHash))
header.FilesystemSize = int(binary.BigEndian.Uint32(FilesystemSize))
header.TableSize = int(binary.BigEndian.Uint32(TableSize))
header.FilesystemUnit = parseUnitSpec(FilesystemUnit)
header.TableUnit = parseUnitSpec(TableUnit)
if header.FilesystemUnit == -1 || header.TableUnit == -1 {
return Header{}, fmt.Errorf("unit size for Filesystem or Table invalid: fs: %x, table: %x", FilesystemUnit, TableUnit)
}
return header, nil
}
func ReadDB(partition string) (string, error) {
_, exist := os.Stat(partition)
if os.IsNotExist(exist) {
return "", fmt.Errorf("Cannot find partition %s", partition)
}
part, err := os.Open(partition)
if err != nil {
return "", err
}
defer part.Close()
reader := bufio.NewReader(part)
_, err = reader.Read(make([]byte, 200))
if err != nil {
fmt.Println(err)
return "", err
}
header, err := ReadHeader(partition)
if err != nil {
fmt.Println(err)
return "", err
}
db := make([]byte, header.TableSize*header.TableUnit)
n, err := io.ReadFull(reader, db)
if err != nil {
fmt.Println("failed reading db")
fmt.Println(header.TableSize * header.TableUnit)
return "", err
}
if n != header.TableSize*header.TableUnit {
return "", fmt.Errorf("Database is not expected size. Expected %d, got %d", header.TableSize*header.TableUnit, n)
}
fmt.Printf("db: %d\n", n)
temp, err := os.MkdirTemp("", "*-fsverify")
if err != nil {
return "", err
}
err = os.WriteFile(temp+"/verify.db", db, 0700)
if err != nil {
return "", err
}
return temp + "/verify.db", nil
}
func OpenDB(dbpath string, readonly bool) (*bolt.DB, error) {
_, exist := os.Stat(dbpath)
if os.IsNotExist(exist) {
os.Create(dbpath)
}
db, err := bolt.Open(dbpath, 0777, &bolt.Options{ReadOnly: readonly})
if err != nil {
return nil, err
}
return db, nil
}
func GetNode(checksum string, db *bolt.DB) (Node, error) {
var err error
var deferDB bool
if db == nil {
db, err = OpenDB("my.db", true)
if err != nil {
return Node{}, err
}
deferDB = true
}
var node Node
err = db.View(func(tx *bolt.Tx) error {
nodes := tx.Bucket([]byte("Nodes"))
app := nodes.Get([]byte(checksum))
err := json.Unmarshal(app, &node)
return err
})
if deferDB {
defer db.Close()
}
return node, err
}
func CopyByteArea(start int, end int, reader *bytes.Reader) ([]byte, error) {
bytes := make([]byte, end-start)
n, err := reader.ReadAt(bytes, int64(start))
if err != nil {
return nil, err
} else if n != end-start {
return nil, fmt.Errorf("Unable to read requested size. Expected %d, got %d", end-start, n)
}
return bytes, nil
}
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