aboutsummaryrefslogtreecommitdiff
path: root/core/storage.go
blob: b3e1b53b620a6333099c46e5ae53e23825f2708c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
package core

import (
	"bufio"
	"encoding/binary"
	"encoding/json"
	"fmt"
	"io"
	"os"
	"strings"

	bolt "go.etcd.io/bbolt"
)

type Header struct {
	MagicNumber    int
	Signature      string
	FilesystemSize int
	TableSize      int
	TableUnit      int
}

type Node struct {
	BlockStart  int
	BlockEnd    int
	BlockSum    string
	PrevNodeSum string
}

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)
	Signature := make([]byte, 302)
	FileSystemSize := make([]byte, 4)
	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(Signature)
	if err != nil {
		return Header{}, err
	}
	_, err = reader.Read(FileSystemSize)
	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 = string(Signature)
	header.FilesystemSize = int(binary.BigEndian.Uint16(FileSystemSize))
	header.TableSize = int(binary.BigEndian.Uint32(TableSize))
	switch TableUnit[0] {
	case 0:
		header.TableUnit = 1
	case 1:
		header.TableUnit = 1000
	case 2:
		header.TableUnit = 1000000
	case 3:
		header.TableUnit = 1000000000
	case 4:
		header.TableUnit = 1000000000000
	case 5:
		header.TableUnit = 1000000000000000
	default:
		return Header{}, fmt.Errorf("Unknown TableUnit %d", 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, 313))
	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)
	_, err = io.ReadFull(reader, db)
	if err != nil {
		return "", err
	}

	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) (*bolt.DB, error) {
	_, exist := os.Stat(dbpath)
	if os.IsNotExist(exist) {
		os.Create(dbpath)
	}
	db, err := bolt.Open(dbpath, 0777, nil)
	if err != nil {
		return nil, err
	}
	return db, nil
}

func AddNode(node Node, db *bolt.DB) error {
	var err error
	var deferDB bool
	if db == nil {
		db, err = OpenDB("my.db")
		if err != nil {
			return err
		}
		deferDB = true
	}
	err = db.Update(func(tx *bolt.Tx) error {
		nodes, err := tx.CreateBucketIfNotExists([]byte("Nodes"))
		if err != nil {
			return err
		}
		if buf, err := json.Marshal(node); err != nil {
			return err
		} else if err := nodes.Put([]byte(node.PrevNodeSum), buf); err != nil {
			return err
		}
		return nil

	})
	if deferDB {
		defer db.Close()
	}
	return err
}

func GetNode(checksum string, db *bolt.DB) (Node, error) {
	var err error
	var deferDB bool
	if db == nil {
		db, err = OpenDB("my.db")
		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 VerifyNode(node Node, nextNode Node) error {
	nodeHash, err := calculateStringHash(fmt.Sprintf("%d%d%s%s", node.BlockStart, node.BlockEnd, node.BlockSum, node.PrevNodeSum))
	if err != nil {
		return err
	}
	if strings.Compare(nodeHash, nextNode.PrevNodeSum) != 0 {
		return fmt.Errorf("Node %s is not valid!", node.PrevNodeSum)
	}
	return nil
}