Started working on the main library (nearly complete)

README.md

@@ -4,13 +4,13 @@
 
 A PURE Go library to read squashfs. There is currently no plans to add archive creation support as it will almost always be better to just call `mksquashfs`. I could see some possible use cases, but probably won't spend time on it unless it's requested (open a discussion if you want this feature).
 
+The library has two parts with this `github.com/CalebQ42/squashfs` being easy to use as it implements `io/fs` interfaces and doesn't expose unnecessary information. 95% this is the library you want. If you need lower level access to the information, use `github.com/CalebQ42/squashfs/squashfs` where far more information is exposed.
+
 Currently has support for reading squashfs files and extracting files and folders.
 
 Special thanks to <https://dr-emann.github.io/squashfs/> for some VERY important information in an easy to understand format.
 Thanks also to [distri's squashfs library](https://github.com/distr1/distri/tree/master/internal/squashfs) as I referenced it to figure some things out (and double check others).
 
-## [TODO](https://github.com/CalebQ42/squashfs/projects/1?fullscreen=true)
-
 ## Limitations
 
 * No Xattr parsing. This is simply because I haven't done any research on it and how to apply these in a pure go way.

extraction_options.go

@@ -0,0 +1,21 @@
+package squashfs
+
+import (
+	"io"
+	"io/fs"
+)
+
+type ExtractionOptions struct {
+	LogOutput          io.Writer   //Where error log should write.
+	DereferenceSymlink bool        //Replace symlinks with the target file.
+	UnbreakSymlink     bool        //Try to make sure symlinks remain unbroken when extracted, without changing the symlink.
+	Verbose            bool        //Prints extra info to log on an error.
+	IgnorePerm         bool        //Ignore file's permissions and instead use Perm.
+	Perm               fs.FileMode //Permission to use when IgnorePerm. Defaults to 0777.
+}
+
+func DefaultOptions() *ExtractionOptions {
+	return &ExtractionOptions{
+		Perm: 0777,
+	}
+}

file.go

@@ -0,0 +1,175 @@
+package squashfs
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+	"path/filepath"
+
+	"github.com/CalebQ42/squashfs/squashfs"
+	"github.com/CalebQ42/squashfs/squashfs/data"
+	"github.com/CalebQ42/squashfs/squashfs/inode"
+)
+
+// File represents a file inside a squashfs archive.
+type File struct {
+	b        *squashfs.Base
+	full     *data.FullReader
+	rdr      *data.Reader
+	parent   *FS
+	r        *Reader
+	dirsRead int
+}
+
+func (f *File) FS() (*FS, error) {
+	if !f.IsDir() {
+		return nil, errors.New("not a directory")
+	}
+	d, err := f.b.ToDir(f.r.r)
+	if err != nil {
+		return nil, err
+	}
+	return &FS{d: d, parent: f.parent, r: f.r}, nil
+}
+
+// Closes the underlying readers.
+// Further calls to Read and WriteTo will re-create the readers.
+// Never returns an error.
+func (f *File) Close() error {
+	if f.rdr != nil {
+		return f.rdr.Close()
+	}
+	f.rdr = nil
+	f.full = nil
+	return nil
+}
+
+// Returns the file the symlink points to.
+// If the file isn't a symlink, or points to a file outside the archive, returns nil.
+func (f *File) GetSymlinkFile() fs.File {
+	if !f.IsSymlink() {
+		return nil
+	}
+	if filepath.IsAbs(f.SymlinkPath()) {
+		return nil
+	}
+	fil, err := f.parent.Open(f.SymlinkPath())
+	if err != nil {
+		return nil
+	}
+	return fil
+}
+
+// Returns whether the file is a directory.
+func (f *File) IsDir() bool {
+	return f.b.IsDir()
+}
+
+// Returns whether the file is a regular file.
+func (f *File) IsRegular() bool {
+	return f.b.IsRegular()
+}
+
+// Returns whether the file is a symlink.
+func (f *File) IsSymlink() bool {
+	return f.b.Inode.Type == inode.Sym || f.b.Inode.Type == inode.ESym
+}
+
+func (f *File) Mode() fs.FileMode {
+	return f.b.Inode.Mode()
+}
+
+// Read reads the data from the file. Only works if file is a normal file.
+func (f *File) Read(b []byte) (int, error) {
+	if !f.IsRegular() {
+		return 0, errors.New("file is not a regular file")
+	}
+	if f.rdr == nil {
+		err := f.initializeReaders()
+		if err != nil {
+			return 0, err
+		}
+	}
+	return f.rdr.Read(b)
+}
+
+// ReadDir returns n fs.DirEntry's that's contained in the File (if it's a directory).
+// If n <= 0 all fs.DirEntry's are returned.
+func (f *File) ReadDir(n int) ([]fs.DirEntry, error) {
+	if !f.IsDir() {
+		return nil, errors.New("file is not a directory")
+	}
+	d, err := f.b.ToDir(f.r.r)
+	if err != nil {
+		return nil, err
+	}
+	start, end := 0, len(d.Entries)
+	if n > 0 {
+		start, end = f.dirsRead, f.dirsRead+n
+		if end > len(d.Entries) {
+			end = len(d.Entries)
+			err = io.EOF
+		}
+	}
+	var out []fs.DirEntry
+	var fi fileInfo
+	for _, e := range d.Entries[start:end] {
+		fi, err = f.r.newFileInfo(e)
+		if err != nil {
+			f.dirsRead += len(out)
+			return out, err
+		}
+		out = append(out, fs.FileInfoToDirEntry(fi))
+	}
+	f.dirsRead += len(out)
+	return out, err
+}
+
+// Returns the file's fs.FileInfo
+func (f *File) Stat() (fs.FileInfo, error) {
+	return newFileInfo(f.b.Name, f.b.Inode), nil
+}
+
+// SymlinkPath returns the symlink's target path. Is the File isn't a symlink, returns an empty string.
+func (f *File) SymlinkPath() string {
+	switch f.b.Inode.Type {
+	case inode.Sym:
+		return string(f.b.Inode.Data.(inode.Symlink).Target)
+	case inode.ESym:
+		return string(f.b.Inode.Data.(inode.ESymlink).Target)
+	}
+	return ""
+}
+
+// Writes all data from the file to the given writer in a multi-threaded manner.
+// The underlying reader is separate
+func (f *File) WriteTo(w io.Writer) (int64, error) {
+	if !f.IsRegular() {
+		return 0, errors.New("file is not a regular file")
+	}
+	if f.full == nil {
+		err := f.initializeReaders()
+		if err != nil {
+			return 0, err
+		}
+	}
+	return f.full.WriteTo(w)
+}
+
+func (f *File) initializeReaders() error {
+	var err error
+	f.rdr, f.full, err = f.b.GetRegFileReaders(f.r.r)
+	return err
+}
+
+// Extract the file to the given folder. If the file is a folder, the folder's contents will be extracted to the folder.
+// Uses default extraction options.
+func (f *File) Extract(folder string) error {
+	return f.ExtractWithOptions(folder, DefaultOptions())
+}
+
+// Extract the file to the given folder. If the file is a folder, the folder's contents will be extracted to the folder.
+// Allows setting various extraction options via ExtractionOptions.
+func (f *File) ExtractWithOptions(folder string, op *ExtractionOptions) error {
+	//TODO
+}

file_info.go

@@ -0,0 +1,68 @@
+package squashfs
+
+import (
+	"io/fs"
+	"time"
+
+	"github.com/CalebQ42/squashfs/squashfs/directory"
+	"github.com/CalebQ42/squashfs/squashfs/inode"
+)
+
+type fileInfo struct {
+	name     string
+	size     int64
+	perm     uint32
+	modTime  uint32
+	fileType uint16
+}
+
+func (r Reader) newFileInfo(e directory.Entry) (fileInfo, error) {
+	i, err := r.r.InodeFromEntry(e)
+	if err != nil {
+		return fileInfo{}, err
+	}
+	return newFileInfo(e.Name, i), nil
+}
+
+func newFileInfo(name string, i *inode.Inode) fileInfo {
+	var size int64
+	if i.Type == inode.Fil {
+		size = int64(i.Data.(inode.File).Size)
+	} else if i.Type == inode.EFil {
+		size = int64(i.Data.(inode.EFile).Size)
+	}
+	return fileInfo{
+		name:     name,
+		size:     size,
+		perm:     uint32(i.Perm),
+		modTime:  i.ModTime,
+		fileType: i.Type,
+	}
+}
+
+func (f fileInfo) Name() string {
+	return f.name
+}
+
+func (f fileInfo) Size() int64 {
+	return f.size
+}
+
+func (f fileInfo) Mode() fs.FileMode {
+	if f.IsDir() {
+		return fs.FileMode(f.perm | uint32(fs.ModeDir))
+	}
+	return fs.FileMode(f.perm)
+}
+
+func (f fileInfo) ModTime() time.Time {
+	return time.Unix(int64(f.modTime), 0)
+}
+
+func (f fileInfo) IsDir() bool {
+	return f.fileType == inode.Dir || f.fileType == inode.EDir
+}
+
+func (f fileInfo) Sys() any {
+	return nil
+}

fs.go

@@ -0,0 +1,241 @@
+package squashfs
+
+import (
+	"io"
+	"io/fs"
+	"path"
+	"path/filepath"
+	"slices"
+	"strings"
+
+	"github.com/CalebQ42/squashfs/squashfs"
+	"github.com/CalebQ42/squashfs/squashfs/directory"
+)
+
+// FS is a fs.FS representation of a squashfs directory.
+// Implements fs.GlobFS, fs.ReadDirFS, fs.ReadFileFS, fs.StatFS, and fs.SubFS
+type FS struct {
+	d      *squashfs.Directory
+	r      *Reader
+	parent *FS
+}
+
+// Glob returns the name of the files at the given pattern.
+// All paths are relative to the FS.
+// Uses filepath.Match to compare names.
+func (f *FS) Glob(pattern string) (out []string, err error) {
+	pattern = filepath.Clean(pattern)
+	if !fs.ValidPath(pattern) {
+		return nil, &fs.PathError{
+			Op:   "glob",
+			Path: pattern,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	split := strings.Split(pattern, "/")
+	for i := 0; i < len(f.d.Entries); i++ {
+		if match, _ := path.Match(split[0], f.d.Entries[i].Name); match {
+			if len(split) == 1 {
+				out = append(out, f.d.Entries[i].Name)
+				continue
+			}
+			sub, err := f.Sub(split[0])
+			if err != nil {
+				if pathErr, ok := err.(*fs.PathError); ok {
+					if pathErr.Err == fs.ErrNotExist {
+						continue
+					}
+					pathErr.Op = "glob"
+					pathErr.Path = pattern
+					return nil, pathErr
+				}
+				return nil, &fs.PathError{
+					Op:   "glob",
+					Path: pattern,
+					Err:  err,
+				}
+			}
+			subGlob, err := sub.(fs.GlobFS).Glob(strings.Join(split[1:], "/"))
+			if err != nil {
+				if pathErr, ok := err.(*fs.PathError); ok {
+					if pathErr.Err == fs.ErrNotExist {
+						continue
+					}
+					pathErr.Op = "glob"
+					pathErr.Path = pattern
+					return nil, pathErr
+				}
+				return nil, &fs.PathError{
+					Op:   "glob",
+					Path: pattern,
+					Err:  err,
+				}
+			}
+			for i := 0; i < len(subGlob); i++ {
+				subGlob[i] = f.d.Name + "/" + subGlob[i]
+			}
+			out = append(out, subGlob...)
+		}
+	}
+	return
+}
+
+// Opens the file at name. Returns a *File as an fs.File.
+func (f *FS) Open(name string) (fs.File, error) {
+	name = filepath.Clean(name)
+	if !fs.ValidPath(name) {
+		return nil, &fs.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if name == "." || name == "" {
+		return &File{
+			b:      &f.d.Base,
+			r:      f.r,
+			parent: f.parent,
+		}, nil
+	}
+	split := strings.Split(name, "/")
+	i, found := slices.BinarySearchFunc(f.d.Entries, split[0], func(e directory.Entry, name string) int {
+		return strings.Compare(e.Name, name)
+	})
+	if !found {
+		return nil, &fs.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  fs.ErrNotExist,
+		}
+	}
+	b, err := f.r.r.BaseFromEntry(f.d.Entries[i])
+	if err != nil {
+		return nil, err
+	}
+	if len(split) == 1 {
+		return &File{
+			b:      b,
+			r:      f.r,
+			parent: f.parent,
+		}, nil
+	}
+	if !b.IsDir() {
+		return nil, &fs.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  fs.ErrNotExist,
+		}
+	}
+	d, err := b.ToDir(f.r.r)
+	if err != nil {
+		return nil, err
+	}
+	return (&FS{
+		d:      d,
+		r:      f.r,
+		parent: f,
+	}).Open(strings.Join(split[1:], "/"))
+}
+
+// Returns all DirEntry's for the directory at name.
+// If name is not a directory, returns an error.
+func (f *FS) ReadDir(name string) ([]fs.DirEntry, error) {
+	name = filepath.Clean(name)
+	if !fs.ValidPath(name) {
+		return nil, &fs.PathError{
+			Op:   "readdir",
+			Path: name,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if name == "." || name == "" {
+		return (&File{
+			b:      &f.d.Base,
+			parent: f.parent,
+			r:      f.r,
+		}).ReadDir(-1)
+	}
+	fil, err := f.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return fil.(*File).ReadDir(-1)
+}
+
+// Returns the contents of the file at name.
+func (f *FS) ReadFile(name string) (out []byte, err error) {
+	name = filepath.Clean(name)
+	if !fs.ValidPath(name) {
+		return nil, &fs.PathError{
+			Op:   "readfile",
+			Path: name,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if name == "." || name == "" {
+		return nil, fs.ErrInvalid
+	}
+	fil, err := f.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	if !fil.(*File).IsRegular() {
+		return nil, fs.ErrInvalid
+	}
+	return io.ReadAll(fil)
+}
+
+// Returns the fs.FileInfo for the file at name.
+func (f *FS) Stat(name string) (fs.FileInfo, error) {
+	name = filepath.Clean(name)
+	if !fs.ValidPath(name) {
+		return nil, &fs.PathError{
+			Op:   "stat",
+			Path: name,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if name == "." || name == "" {
+		return (&File{
+			b:      &f.d.Base,
+			parent: f.parent,
+			r:      f.r,
+		}).Stat()
+	}
+	fil, err := f.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return fil.(*File).Stat()
+}
+
+// Returns the FS at dir
+func (f *FS) Sub(dir string) (fs.FS, error) {
+	dir = filepath.Clean(dir)
+	if !fs.ValidPath(dir) {
+		return nil, &fs.PathError{
+			Op:   "dir",
+			Path: dir,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if dir == "." || dir == "" {
+		return f, nil
+	}
+	fil, err := f.Open(dir)
+	if err != nil {
+		return nil, err
+	}
+	if !fil.(*File).IsDir() {
+		return nil, &fs.PathError{
+			Op:   "dir",
+			Path: dir,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	return fil.(*File).FS()
+}
+
+func (f *FS) path() string {
+	return filepath.Join(f.parent.path(), f.d.Name)
+}

reader.go

@@ -0,0 +1,30 @@
+package squashfs
+
+import (
+	"io"
+	"time"
+
+	"github.com/CalebQ42/squashfs/squashfs"
+)
+
+type Reader struct {
+	*FS
+	r *squashfs.Reader
+}
+
+func NewReader(r io.ReaderAt) (*Reader, error) {
+	rdr, err := squashfs.NewReader(r)
+	if err != nil {
+		return nil, err
+	}
+	return &Reader{
+		r: rdr,
+		FS: &FS{
+			d: rdr.Root,
+		},
+	}, nil
+}
+
+func (r *Reader) ModTime() time.Time {
+	return time.Unix(int64(r.r.Superblock.ModTime), 0)
+}

squashfs/base.go

@@ -21,10 +21,7 @@ func (r *Reader) BaseFromInode(i *inode.Inode, name string) *Base {
 }
 
 func (r *Reader) BaseFromEntry(e directory.Entry) (*Base, error) {
-	rdr := metadata.NewReader(toreader.NewReader(r.r, int64(r.Superblock.InodeTableStart)+int64(e.BlockStart)), r.d)
-	defer rdr.Close()
-	rdr.Read(make([]byte, e.Offset))
-	in, err := inode.Read(rdr, r.Superblock.BlockSize)
+	in, err := r.InodeFromEntry(e)
 	if err != nil {
 		return nil, err
 	}
@@ -32,7 +29,7 @@ func (r *Reader) BaseFromEntry(e directory.Entry) (*Base, error) {
 }
 
 func (r *Reader) BaseFromRef(ref uint64, name string) (*Base, error) {
-	in, err := r.inodeFromRef(ref)
+	in, err := r.InodeFromRef(ref)
 	if err != nil {
 		return nil, err
 	}

squashfs/directory.go

@@ -20,7 +20,7 @@ type Directory struct {
 }
 
 func (r *Reader) directoryFromRef(ref uint64, name string) (*Directory, error) {
-	i, err := r.inodeFromRef(ref)
+	i, err := r.InodeFromRef(ref)
 	if err != nil {
 		fmt.Println("yo")
 		return nil, err

squashfs/inode.go

@@ -3,10 +3,11 @@ package squashfs
 import (
 	"github.com/CalebQ42/squashfs/internal/metadata"
 	"github.com/CalebQ42/squashfs/internal/toreader"
+	"github.com/CalebQ42/squashfs/squashfs/directory"
 	"github.com/CalebQ42/squashfs/squashfs/inode"
 )
 
-func (r *Reader) inodeFromRef(ref uint64) (*inode.Inode, error) {
+func (r *Reader) InodeFromRef(ref uint64) (*inode.Inode, error) {
 	offset, meta := (ref>>16)+r.Superblock.InodeTableStart, ref&0xFFFF
 	rdr := metadata.NewReader(toreader.NewReader(r.r, int64(offset)), r.d)
 	defer rdr.Close()
@@ -16,3 +17,10 @@ func (r *Reader) inodeFromRef(ref uint64) (*inode.Inode, error) {
 	}
 	return inode.Read(rdr, r.Superblock.BlockSize)
 }
+
+func (r *Reader) InodeFromEntry(e directory.Entry) (*inode.Inode, error) {
+	rdr := metadata.NewReader(toreader.NewReader(r.r, int64(r.Superblock.InodeTableStart)+int64(e.BlockStart)), r.d)
+	defer rdr.Close()
+	rdr.Read(make([]byte, e.Offset))
+	return inode.Read(rdr, r.Superblock.BlockSize)
+}

squashfs/reader.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"io"
 	"math"
-	"time"
 
 	"github.com/CalebQ42/squashfs/internal/decompress"
 	"github.com/CalebQ42/squashfs/internal/metadata"
@@ -79,11 +78,6 @@ func NewReader(r io.ReaderAt) (rdr *Reader, err error) {
 	return
 }
 
-// Returns the last time the archive was modified.
-func (r *Reader) ModTime() time.Time {
-	return time.Unix(int64(r.Superblock.ModTime), 0)
-}
-
 // Get a uid/gid at the given index. Lazily populates the reader's Id table as necessary.
 func (r *Reader) Id(i uint16) (uint32, error) {
 	if len(r.idTable) > int(i) {
@@ -221,5 +215,5 @@ func (r *Reader) Inode(i uint32) (*inode.Inode, error) {
 	if err != nil {
 		return nil, err
 	}
-	return r.inodeFromRef(ref)
+	return r.InodeFromRef(ref)
 }