Caleb Gardner
68 lines
1.9 KiB
Go
68 lines
1.9 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/GoSquashfs/internal/directory"
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"github.com/CalebQ42/GoSquashfs/internal/inode"
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)
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//ProcessInodeRef processes an inode reference and returns two values
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//
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//The first value is the inode table offset. AKA, it's where the metadata block of the inode STARTS relative to the inode table.
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//
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//The second value is the offset of the inode, INSIDE of the metadata.
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func processInodeRef(inodeRef uint64) (tableOffset uint64, metaOffset uint64) {
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tableOffset = inodeRef >> 16
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metaOffset = inodeRef &^ 0xFFFFFFFF0000
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return
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}
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func (r *Reader) ReadDirFromInode(i inode.Inode) (*directory.Directory, error) {
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var offset uint32
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var metaOffset uint16
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var size uint16
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switch i.Type {
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case inode.BasicDirectoryType:
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offset = i.Info.(inode.BasicDirectory).DirectoryIndex
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metaOffset = i.Info.(inode.BasicDirectory).DirectoryOffset
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size = i.Info.(inode.BasicDirectory).DirectorySize
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case inode.ExtDirType:
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offset = i.Info.(inode.ExtendedDirectory).Init.DirectoryIndex
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metaOffset = i.Info.(inode.ExtendedDirectory).Init.DirectoryOffset
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size = uint16(i.Info.(inode.ExtendedDirectory).Init.DirectorySize)
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default:
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return nil, errors.New("Not a directory inode")
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}
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br, err := r.NewBlockReader(int64(r.super.DirTableStart + uint64(offset)))
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if err != nil {
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return nil, err
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}
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_, err = br.Seek(int64(metaOffset), io.SeekStart)
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if err != nil {
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return nil, err
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}
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dir, err := directory.NewDirectory(br, size)
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if err != nil {
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return dir, err
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}
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return dir, nil
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}
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func (r *Reader) GetInodeFromEntry(en *directory.Entry) (*inode.Inode, error) {
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br, err := r.NewBlockReader(int64(r.super.InodeTableStart + uint64(en.Header.InodeOffset)))
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if err != nil {
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return nil, err
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}
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_, err = br.Seek(int64(en.Init.Offset), io.SeekStart)
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if err != nil {
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return nil, err
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}
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i, err := inode.ProcessInode(br, r.super.BlockSize)
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if err != nil {
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return nil, err
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}
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return &i, nil
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}
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