Fixed a race condition with mounts that caused them to fail

fuse.go

@@ -3,6 +3,7 @@ package squashfs
 import (
 	"bytes"
 	"context"
+	"errors"
 	"io"
 
 	"github.com/CalebQ42/fuse"
@@ -10,17 +11,38 @@ import (
 	"github.com/CalebQ42/squashfs/internal/inode"
 )
 
-// Creates a fuse mount, then mounts the archive on a seperate goroutine.
-// If waiting for the mount to end, simply do <-con.Ready.
-func (r *Reader) Mount(mountpoint string) (con *fuse.Conn, err error) {
-	con, err = fuse.Mount(mountpoint, fuse.ReadOnly())
+// Mounts the archive to the given mountpoint using fuse3.
+// Blocks until the arhive is unmounted.
+// Hightly suggested to run in a goroutine.
+// Will take a moment before MountWait and Unmount will work correctly.
+func (r *Reader) Mount(mountpoint string) (err error) {
+	if r.con != nil {
+		return errors.New("squashfs archive already mounted")
+	}
+	r.con, err = fuse.Mount(mountpoint, fuse.ReadOnly())
 	if err != nil {
 		return
 	}
-	go fs.Serve(con, &squashFuse{r: r})
+	err = fs.Serve(r.con, &squashFuse{r: r})
 	return
 }
 
+// Blocks until the mount ends.
+func (r *Reader) MountWait() {
+	if r.con != nil {
+		<-r.con.Ready
+	}
+}
+
+// Unmounts the archive.
+func (r *Reader) Unmount() error {
+	if r.con != nil {
+		defer func() { r.con = nil }()
+		return r.con.Close()
+	}
+	return errors.New("squashfs archive is not mounted")
+}
+
 type squashFuse struct {
 	r *Reader
 }

internal/toreader/offsetreader.go

@@ -0,0 +1,19 @@
+package toreader
+
+import "io"
+
+type OffsetReader struct {
+	r   io.ReaderAt
+	off int64
+}
+
+func NewOffsetReader(r io.ReaderAt, off int64) *OffsetReader {
+	return &OffsetReader{
+		r:   r,
+		off: off,
+	}
+}
+
+func (r OffsetReader) ReadAt(p []byte, off int64) (n int, e error) {
+	return r.r.ReadAt(p, off+r.off)
+}

internal/toreader/readerat.go

@@ -6,7 +6,8 @@ type ReaderAt struct {
 	d []byte
 }
 
-func NewReaderAt(r io.Reader) (ra ReaderAt, err error) {
+func NewReaderAt(r io.Reader) (ra *ReaderAt, err error) {
+	ra = new(ReaderAt)
 	ra.d, err = io.ReadAll(r)
 	return
 }

reader.go

@@ -7,6 +7,7 @@ import (
 	"math"
 	"time"
 
+	"github.com/CalebQ42/fuse"
 	"github.com/CalebQ42/squashfs/internal/decompress"
 	"github.com/CalebQ42/squashfs/internal/directory"
 	"github.com/CalebQ42/squashfs/internal/inode"
@@ -16,6 +17,7 @@ import (
 
 type Reader struct {
 	*FS
+	con         *fuse.Conn
 	d           decompress.Decompressor
 	r           io.ReaderAt
 	fragEntries []fragEntry
@@ -40,6 +42,10 @@ const (
 	ZSTDCompression
 )
 
+func NewReaderAtOffset(r io.ReaderAt, off int64) (*Reader, error) {
+	return NewReader(toreader.NewOffsetReader(r, off))
+}
+
 // Creates a new squashfs.Reader from the given io.Reader. NOTE: All data from the io.Reader will be read and stored in memory.
 func NewReaderFromReader(r io.Reader) (*Reader, error) {
 	rdr, err := toreader.NewReaderAt(r)

squashfs_test.go

@@ -196,11 +196,11 @@ func TestFuse(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	con, err := rdr.Mount("testing/fuseTest")
+	err = rdr.Mount("testing/fuseTest")
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer con.Close()
-	<-con.Ready
+	defer rdr.Unmount()
+	rdr.MountWait()
 	t.Fatal("testing")
 }