Caleb Gardner
92 lines
2.0 KiB
Go
92 lines
2.0 KiB
Go
package directory
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import (
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"encoding/binary"
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"fmt"
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"io"
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)
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//Header is the header for a directory in the directory table
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type Header struct {
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Count uint32
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InodeOffset uint32
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InodeNumber uint32
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}
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//EntryInit is the values that can be easily decoded
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type EntryInit struct {
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Offset uint16
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InodeOffset int16
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Type uint16
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NameSize uint16
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}
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//Entry is an entry in a directory.
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type Entry struct {
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Init EntryInit
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Name []byte
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}
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//NewEntry creates a new directory entry
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func NewEntry(rdr io.Reader) (Entry, error) {
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var entry Entry
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err := binary.Read(rdr, binary.LittleEndian, &entry.Init)
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fmt.Println("entry", entry.Init)
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if err != nil {
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return Entry{}, err
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}
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entry.Name = make([]byte, entry.Init.NameSize+1, entry.Init.NameSize+1)
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err = binary.Read(rdr, binary.LittleEndian, &entry.Name)
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if err != nil {
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return Entry{}, err
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}
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return entry, err
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}
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//Directory is an entry in the directory table of a squashfs.
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//Will only have multiple headers if there are more then 256 entries
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type Directory struct {
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Headers []Header
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Entries []Entry
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}
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//NewDirectory reads the directory from rdr
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func NewDirectory(rdr io.Reader) (*Directory, error) {
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var dir Directory
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var hdr Header
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err := binary.Read(rdr, binary.LittleEndian, &hdr)
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if err != nil {
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return nil, err
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}
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hdr.Count++
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fmt.Println("entries coutn", hdr.Count)
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headers := hdr.Count / 256
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if hdr.Count%256 > 0 {
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headers++
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}
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headersRead := 1
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dir.Headers = make([]Header, headers)
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dir.Headers[0] = hdr
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for i := uint32(0); i < hdr.Count; i++ {
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fmt.Println("reading entry", i)
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if i != 0 && i%256 == 0 {
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fmt.Println("reading new header...")
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var newHdr Header
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err = binary.Read(rdr, binary.LittleEndian, &newHdr)
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if err != nil {
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fmt.Println("Error processing header ", headersRead)
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return &dir, err
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}
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dir.Headers[headersRead] = newHdr
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headersRead++
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}
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ent, err := NewEntry(rdr)
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if err != nil {
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fmt.Println("Error processing entry ", len(dir.Entries))
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return &dir, err
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}
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dir.Entries = append(dir.Entries, ent)
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}
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return &dir, nil
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}
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