Further work on directory table reading

This commit is contained in:
Caleb Gardner
2020-11-18 22:24:26 -06:00
parent 774366004c
commit be1be40a17
5 changed files with 58 additions and 30 deletions
+23 -3
View File
@@ -37,6 +37,28 @@ func (s *Reader) NewBlockReader(offset int64) (*BlockReader, error) {
return &br, nil
}
func (s *Reader) NewBlockReaderFromInodeRef(ref uint64) (*BlockReader, error) {
offset, metaOffset := processInodeRef(ref)
br, err := s.NewBlockReader(int64(s.super.InodeTableStart + offset))
if err != nil {
return nil, err
}
_, err = br.Seek(int64(metaOffset), io.SeekStart)
if err != nil {
return nil, err
}
return br, nil
}
func (s *Reader) NewBlockReaderFromDirIndex(index uint64) (*BlockReader, error) {
br, err := s.NewBlockReader(int64(s.super.DirTableStart))
if err != nil {
return nil, err
}
readIndex := 0
for readIndex <
}
func (br *BlockReader) parseMetadata() error {
var raw uint16
err := binary.Read(io.NewSectionReader(br.s.r, br.offset, 2), binary.LittleEndian, &raw)
@@ -77,18 +99,16 @@ func (br *BlockReader) readNextDataBlock() error {
}
func (br *BlockReader) Read(p []byte) (int, error) {
fmt.Println("reading", len(p))
fmt.Println("reading", len(p), "bytes")
if br.readOffset+len(p) < len(br.data) {
for i := 0; i < len(p); i++ {
p[i] = br.data[br.readOffset+i]
}
br.readOffset += len(p)
fmt.Println("enough data available")
return len(p), nil
}
read := 0
for read < len(p) {
fmt.Println("Reading new block")
err := br.parseMetadata()
if err != nil {
br.readOffset += read
+9 -12
View File
@@ -4,6 +4,7 @@ import (
"encoding/binary"
"fmt"
"io"
"math"
)
//Header is the header for a directory in the directory table
@@ -28,26 +29,25 @@ type Entry struct {
}
//NewEntry creates a new directory entry
func NewEntry(rdr io.Reader) (Entry, error) {
func NewEntry(rdr io.Reader) (*Entry, error) {
var entry Entry
err := binary.Read(rdr, binary.LittleEndian, &entry.Init)
fmt.Println("entry", entry.Init)
if err != nil {
return Entry{}, err
return nil, err
}
entry.Name = make([]byte, entry.Init.NameSize+1, entry.Init.NameSize+1)
entry.Name = make([]byte, entry.Init.NameSize+1)
err = binary.Read(rdr, binary.LittleEndian, &entry.Name)
if err != nil {
return Entry{}, err
return nil, err
}
return entry, err
return &entry, err
}
//Directory is an entry in the directory table of a squashfs.
//Will only have multiple headers if there are more then 256 entries
type Directory struct {
Headers []Header
Entries []Entry
Entries []*Entry
}
//NewDirectory reads the directory from rdr
@@ -59,22 +59,20 @@ func NewDirectory(rdr io.Reader) (*Directory, error) {
return nil, err
}
hdr.Count++
fmt.Println("entries coutn", hdr.Count)
headers := hdr.Count / 256
if hdr.Count%256 > 0 {
headers++
}
fmt.Println("headers", headers)
fmt.Println("headers ceil", math.Ceil(float64(hdr.Count)/256))
headersRead := 1
dir.Headers = make([]Header, headers)
dir.Headers[0] = hdr
for i := uint32(0); i < hdr.Count; i++ {
fmt.Println("reading entry", i)
if i != 0 && i%256 == 0 {
fmt.Println("reading new header...")
var newHdr Header
err = binary.Read(rdr, binary.LittleEndian, &newHdr)
if err != nil {
fmt.Println("Error processing header ", headersRead)
return &dir, err
}
dir.Headers[headersRead] = newHdr
@@ -82,7 +80,6 @@ func NewDirectory(rdr io.Reader) (*Directory, error) {
}
ent, err := NewEntry(rdr)
if err != nil {
fmt.Println("Error processing entry ", len(dir.Entries))
return &dir, err
}
dir.Entries = append(dir.Entries, ent)
+1 -1
View File
@@ -35,7 +35,7 @@ func TestMain(t *testing.T) {
if err != nil {
t.Fatal(err)
}
err = rdr.readRootDirTable()
err = rdr.readDirTable()
if err != nil {
t.Fatal(err)
}
+8 -14
View File
@@ -19,6 +19,7 @@ type Reader struct {
super Superblock
flags SuperblockFlags
decompressor Decompressor
dirs []*directory.Directory
}
func NewSquashfsReader(r io.ReaderAt) (*Reader, error) {
@@ -46,31 +47,24 @@ func NewSquashfsReader(r io.ReaderAt) (*Reader, error) {
return &rdr, nil
}
func (r *Reader) readRootDirTable() error {
offset, blockOffset := processInodeRef(r.super.RootInodeRef)
br, err := r.NewBlockReader(int64(r.super.InodeTableStart + offset))
func (r *Reader) readDirTable() error {
inoderdr, err := r.NewBlockReaderFromInodeRef(r.super.RootInodeRef)
if err != nil {
return err
}
_, err = br.Seek(int64(blockOffset), io.SeekStart)
i, err := inode.ProcessInode(inoderdr, r.super.BlockSize)
if err != nil {
return err
}
i, err := inode.ProcessInode(br, r.super.BlockSize)
inDir := i.Info.(inode.BasicDirectory)
dirrdr, err := r.NewBlockReader(int64(r.super.DirTableStart) + int64(inDir.DirectoryIndex))
if err != nil {
return err
}
fmt.Println("Done reading inode...")
dirRdr, err := r.NewBlockReader(int64(r.super.DirTableStart + uint64(i.Info.(inode.BasicDirectory).DirectoryIndex)))
dir, err := directory.NewDirectory(dirrdr)
if err != nil {
return err
}
dir, err := directory.NewDirectory(dirRdr)
if err != nil {
return err
}
for _, entry := range dir.Entries {
fmt.Println(string(entry.Name))
}
fmt.Println("Entries", len(dir.Entries))
return nil
}
+17
View File
@@ -1,5 +1,12 @@
package squashfs
import (
"errors"
"github.com/CalebQ42/GoSquashfs/internal/directory"
"github.com/CalebQ42/GoSquashfs/internal/inode"
)
//ProcessInodeRef processes an inode reference and returns two values
//
//The first value is the inode table offset. AKA, it's where the metadata block of the inode STARTS relative to the inode table.
@@ -10,3 +17,13 @@ func processInodeRef(inodeRef uint64) (tableOffset uint64, metaOffset uint64) {
metaOffset = inodeRef &^ 0xFFFFFFFF0000
return
}
func (r *Reader) ReadDirFromInode(i inode.Inode) (*directory.Directory, error) {
if i.Type == inode.BasicDirectoryType {
} else if i.Type == inode.ExtDirType {
} else {
return nil, errors.New("Not a directory inode")
}
}