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Directorty table info parsing.

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Futher work on reading data.
This commit is contained in:
Caleb Gardner
2020-11-13 04:47:54 -06:00
parent f135457443
commit dbf7e9465a
9 changed files with 288 additions and 114 deletions
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squashfs.go
+45 -11
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@@ -3,7 +3,10 @@ package squashfs
import (
"encoding/binary"
"errors"
"fmt"
"io"
"github.com/CalebQ42/GoSquashfs/internal/inode"
)
var (
@@ -34,7 +37,7 @@ func NewSquashfs(reader io.ReaderAt) (*Squashfs, error) {
flags := superblock.GetFlags()
var compressionOptions CompressionOptions
switch superblock.Compression {
case zlibCompression:
case gzipCompression:
if flags.CompressorOptions {
var gzipOpRaw gzipOptionsRaw
err = binary.Read(&rdr, binary.LittleEndian, &gzipOpRaw)
@@ -69,9 +72,39 @@ func NewSquashfs(reader io.ReaderAt) (*Squashfs, error) {
}, nil
}
func (s *Squashfs) readRootDirectoryTable() error {
offset, metaOffset := inode.ProcessInodeRef(s.super.RootInode)
meta, err := s.parseMetadataAt(int64(s.super.InodeTableOffset) + int64(offset))
if err != nil {
fmt.Println("Error processing metadata")
return err
}
_, err = meta.Data.Read(make([]byte, metaOffset))
if err != nil {
fmt.Println("error reading forward to offset")
return err
}
common, _, err := inode.ProcessInode(&meta.Data, s.super.BlockSize)
if err != nil {
fmt.Println("Error reading inode")
return err
}
if common.InodeType != inode.BasicDirectoryType {
return errors.New("Not a basic directory")
}
// dirTable, err := directory.NewDirectory(meta.Data)
// if err != nil {
// return err
// }
// for _, entry := range dirTable.Entries {
// fmt.Println(entry.Name)
// }
return nil
}
//GetFlags return the SuperblockFlags of the Squashfs
func (s *Squashfs) GetFlags() SuperblockFlags {
return s.super.GetFlags()
return s.flags
}
//metadata is a parsed metadata block
@@ -90,13 +123,14 @@ func (m *metadata) close() {
func (s *Squashfs) parseNextMetadata() (*metadata, error) {
var metaHeader uint16
err := binary.Read(s.rdr, binary.LittleEndian, metaHeader)
err := binary.Read(s.rdr, binary.LittleEndian, &metaHeader)
if err != nil {
return nil, err
}
reader := io.NewSectionReader(s.rdr, s.rdr.offset, s.rdr.offset+int64(metaHeader))
if metaHeader&0x8000 == 0x8000 {
metaHeader = metaHeader &^ 0x8000
compressRead, err := s.compressionOptions.Reader(io.NewSectionReader(s.rdr, s.rdr.offset, int64(metaHeader)))
compressRead, err := s.compressionOptions.Reader(reader)
return &metadata{
Compressed: true,
Size: metaHeader,
@@ -106,19 +140,19 @@ func (s *Squashfs) parseNextMetadata() (*metadata, error) {
return &metadata{
Compressed: false,
Size: metaHeader,
Data: io.NewSectionReader(s.rdr, s.rdr.offset, int64(metaHeader)),
Data: reader,
}, nil
}
func (s *Squashfs) parseMetadataAt(offset int64) (*metadata, error) {
var metaHeader uint16
err := binary.Read(s.rdr, binary.LittleEndian, metaHeader)
if err != nil {
return nil, err
}
var headerBytes []byte
headerBytes = make([]byte, 2)
s.rdr.ReadAt(headerBytes, offset)
metaHeader = binary.LittleEndian.Uint16(headerBytes)
if metaHeader&0x8000 == 0x8000 {
metaHeader = metaHeader &^ 0x8000
compressRead, err := s.compressionOptions.Reader(io.NewSectionReader(s.rdr, offset, int64(metaHeader)))
compressRead, err := s.compressionOptions.Reader(io.NewSectionReader(s.rdr, s.rdr.offset, s.rdr.offset+int64(s.super.BlockSize)))
return &metadata{
Compressed: true,
Size: metaHeader,
@@ -128,6 +162,6 @@ func (s *Squashfs) parseMetadataAt(offset int64) (*metadata, error) {
return &metadata{
Compressed: false,
Size: metaHeader,
Data: io.NewSectionReader(s.rdr, offset, int64(metaHeader)),
Data: io.NewSectionReader(s.rdr, s.rdr.offset, s.rdr.offset+int64(s.super.BlockSize)),
}, nil
}