Caleb Gardner
118 lines
3.6 KiB
Go
118 lines
3.6 KiB
Go
package squashfs
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import (
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"errors"
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"io"
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"github.com/CalebQ42/squashfs/internal/data"
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"github.com/CalebQ42/squashfs/internal/directory"
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"github.com/CalebQ42/squashfs/internal/inode"
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"github.com/CalebQ42/squashfs/internal/metadata"
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"github.com/CalebQ42/squashfs/internal/toreader"
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)
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func (r Reader) inodeFromRef(ref uint64) (i inode.Inode, err error) {
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offset, meta := (ref>>16)+r.s.InodeTableStart, ref&0xFFFF
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rdr := metadata.NewReader(toreader.NewReader(r.r, int64(offset)), r.d)
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_, err = rdr.Read(make([]byte, meta))
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if err != nil {
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return
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}
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return inode.Read(rdr, r.s.BlockSize)
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}
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func (r Reader) inodeFromDir(e directory.Entry) (i inode.Inode, err error) {
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rdr := metadata.NewReader(toreader.NewReader(r.r, int64(uint64(e.BlockStart)+r.s.InodeTableStart)), r.d)
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_, err = rdr.Read(make([]byte, e.Offset))
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if err != nil {
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return
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}
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return inode.Read(rdr, r.s.BlockSize)
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}
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func (r Reader) getReaders(i inode.Inode) (full *data.FullReader, rdr *data.Reader, err error) {
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var fragOffset uint64
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var blockOffset uint64
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var blockSizes []uint32
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var fragInd uint32
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var fragSize uint32
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var fileSize uint64
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if i.Type == inode.Fil {
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fragOffset = uint64(i.Data.(inode.File).FragOffset)
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blockOffset = uint64(i.Data.(inode.File).BlockStart)
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blockSizes = i.Data.(inode.File).BlockSizes
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fragInd = i.Data.(inode.File).FragInd
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fragSize = i.Data.(inode.File).Size % r.s.BlockSize
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fileSize = uint64(i.Data.(inode.File).Size)
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} else if i.Type == inode.EFil {
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fragOffset = uint64(i.Data.(inode.EFile).FragOffset)
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blockOffset = i.Data.(inode.EFile).BlockStart
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blockSizes = i.Data.(inode.EFile).BlockSizes
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fragInd = i.Data.(inode.EFile).FragInd
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fragSize = uint32(i.Data.(inode.EFile).Size % uint64(r.s.BlockSize))
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fileSize = i.Data.(inode.EFile).Size
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} else {
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return nil, nil, errors.New("getReaders called on non-file type")
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}
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rdr = data.NewReader(toreader.NewReader(r.r, int64(blockOffset)), r.d, blockSizes, r.s.BlockSize)
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full = data.NewFullReader(r.r, uint64(blockOffset), r.d, blockSizes, r.s.BlockSize, fileSize)
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if fragInd != 0xFFFFFFFF {
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full.AddFragment(func() (io.Reader, error) {
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var fragRdr io.Reader
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fragRdr, err = r.fragReader(fragInd)
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if err != nil {
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return nil, err
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}
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var n, tmpN int
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for n != int(fragOffset) {
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tmpN, err = fragRdr.Read(make([]byte, int(fragOffset)-n))
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if err != nil {
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return nil, err
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}
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n += tmpN
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}
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fragRdr = io.LimitReader(fragRdr, int64(fragSize))
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return fragRdr, nil
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})
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var fragRdr io.Reader
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fragRdr, err = r.fragReader(fragInd)
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if err != nil {
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return nil, nil, err
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}
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var n, tmpN int
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for n != int(fragOffset) {
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tmpN, err = fragRdr.Read(make([]byte, int(fragOffset)-n))
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if err != nil {
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return nil, nil, err
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}
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n += tmpN
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}
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fragRdr = io.LimitReader(fragRdr, int64(fragSize))
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rdr.AddFragment(fragRdr)
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}
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return
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}
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func (r Reader) readDirectory(i inode.Inode) ([]directory.Entry, error) {
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var offset uint64
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var blockOffset uint16
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var size uint32
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if i.Type == inode.Dir {
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offset = uint64(i.Data.(inode.Directory).BlockStart)
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blockOffset = i.Data.(inode.Directory).Offset
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size = uint32(i.Data.(inode.Directory).Size)
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} else if i.Type == inode.EDir {
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offset = uint64(i.Data.(inode.EDirectory).BlockStart)
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blockOffset = i.Data.(inode.EDirectory).Offset
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size = i.Data.(inode.EDirectory).Size
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} else {
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return nil, errors.New("readDirectory called on non-directory type")
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}
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rdr := metadata.NewReader(toreader.NewReader(r.r, int64(offset+r.s.DirTableStart)), r.d)
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_, err := rdr.Read(make([]byte, blockOffset))
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if err != nil {
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return nil, err
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}
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return directory.ReadEntries(rdr, size)
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}
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