Add pathfs frontend (uses go-fuse instead of bazil-fuse), part I

Currently fails main_test.go, will be fixed in part II

1 files changed, 166 insertions, 0 deletions

diff --git a/pathfs_frontend/fs.go b/pathfs_frontend/fs.go
new file mode 100644
index 0000000..2f73462
--- /dev/null
+++ b/pathfs_frontend/fs.go
@@ -0,0 +1,166 @@
+package pathfs_frontend
+
+import (
+	"os"
+	"path/filepath"
+	"time"
+	"fmt"
+
+	"github.com/hanwen/go-fuse/fuse"
+	"github.com/hanwen/go-fuse/fuse/nodefs"
+	"github.com/hanwen/go-fuse/fuse/pathfs"
+	"github.com/rfjakob/gocryptfs/cryptfs"
+)
+
+type FS struct {
+	*cryptfs.CryptFS
+	pathfs.FileSystem    // loopbackFileSystem
+	backing string       // Backing directory
+}
+
+// Encrypted FUSE overlay filesystem
+func NewFS(key [16]byte, backing string, useOpenssl bool) *FS {
+	return &FS{
+		CryptFS:     cryptfs.NewCryptFS(key, useOpenssl),
+		FileSystem:  pathfs.NewLoopbackFileSystem(backing),
+		backing:     backing,
+
+	}
+}
+
+// GetPath - get the absolute path of the backing file
+func (fs *FS) GetPath(relPath string) string {
+	return filepath.Join(fs.backing, fs.EncryptPath(relPath))
+}
+
+func (fs *FS) GetAttr(name string, context *fuse.Context) (*fuse.Attr, fuse.Status) {
+	a, status := fs.FileSystem.GetAttr(fs.EncryptPath(name), context)
+	if a == nil {
+		return a, status
+	}
+
+	a.Size = fs.PlainSize(a.Size)
+	return a, status
+}
+
+func (fs *FS) OpenDir(name string, context *fuse.Context) ([]fuse.DirEntry, fuse.Status) {
+	cipherEntries, status := fs.FileSystem.OpenDir(fs.EncryptPath(name), context);
+	var plain []fuse.DirEntry
+	var skipped int
+	if cipherEntries != nil {
+		for i := range cipherEntries {
+			n, err := fs.DecryptPath(cipherEntries[i].Name)
+			if err != nil {
+				fmt.Printf("Skipping invalid filename \"%s\": %s\n", cipherEntries[i].Name, err)
+				skipped++
+				continue
+			}
+			cipherEntries[i].Name = n
+			plain = append(plain, cipherEntries[i])
+		}
+	}
+	return plain, status
+}
+
+// We always need read access to do read-modify-write cycles
+func (fs *FS) mangleOpenFlags(flags uint32) (newFlags int, writeOnly bool) {
+	newFlags = int(flags)
+	if newFlags & os.O_WRONLY > 0 {
+		writeOnly = true
+		newFlags = newFlags ^ os.O_WRONLY | os.O_RDWR
+	}
+	// We also cannot open the file in append mode, we need to seek back for RMW
+	newFlags = newFlags &^ os.O_APPEND
+
+	return newFlags, writeOnly
+}
+
+func (fs *FS) Open(name string, flags uint32, context *fuse.Context) (fuseFile nodefs.File, status fuse.Status) {
+	cryptfs.Debug.Printf("Open(%s)\n", name)
+
+	iflags, writeOnly := fs.mangleOpenFlags(flags)
+	f, err := os.OpenFile(fs.GetPath(name), iflags, 0666)
+	if err != nil {
+		return nil, fuse.ToStatus(err)
+	}
+
+	return NewFile(f, writeOnly, fs.CryptFS), fuse.OK
+}
+
+func (fs *FS) Create(path string, flags uint32, mode uint32, context *fuse.Context) (fuseFile nodefs.File, code fuse.Status) {
+	iflags, writeOnly := fs.mangleOpenFlags(flags)
+	f, err := os.OpenFile(fs.GetPath(path), iflags|os.O_CREATE, os.FileMode(mode))
+	if err != nil {
+		return nil, fuse.ToStatus(err)
+	}
+	return NewFile(f, writeOnly, fs.CryptFS), fuse.OK
+}
+
+func (fs *FS) Chmod(path string, mode uint32, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Chmod(fs.EncryptPath(path), mode, context)
+}
+
+func (fs *FS) Chown(path string, uid uint32, gid uint32, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Chmod(fs.EncryptPath(path), gid, context)
+}
+
+func (fs *FS) Truncate(path string, offset uint64, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Truncate(fs.EncryptPath(path), offset, context)
+}
+
+func (fs *FS) Utimens(path string, Atime *time.Time, Mtime *time.Time, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Utimens(fs.EncryptPath(path), Atime, Mtime, context)
+}
+
+func (fs *FS) Readlink(name string, context *fuse.Context) (out string, code fuse.Status) {
+	return fs.FileSystem.Readlink(fs.EncryptPath(name), context)
+}
+
+func (fs *FS) Mknod(name string, mode uint32, dev uint32, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Mknod(fs.EncryptPath(name), mode, dev, context)
+}
+
+func (fs *FS) Mkdir(path string, mode uint32, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Mkdir(fs.EncryptPath(path), mode, context)
+}
+
+func (fs *FS) Unlink(name string, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Unlink(fs.EncryptPath(name), context)
+}
+
+func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Rmdir(fs.EncryptPath(name), context)
+}
+
+func (fs *FS) Symlink(pointedTo string, linkName string, context *fuse.Context) (code fuse.Status) {
+	// TODO symlink encryption
+	return fs.FileSystem.Symlink(fs.EncryptPath(pointedTo), fs.EncryptPath(linkName), context)
+}
+
+func (fs *FS) Rename(oldPath string, newPath string, context *fuse.Context) (codee fuse.Status) {
+	return fs.FileSystem.Rename(fs.EncryptPath(oldPath), fs.EncryptPath(newPath), context)
+}
+
+func (fs *FS) Link(orig string, newName string, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Link(fs.EncryptPath(orig), fs.EncryptPath(newName), context)
+}
+
+func (fs *FS) Access(name string, mode uint32, context *fuse.Context) (code fuse.Status) {
+	return fs.FileSystem.Access(fs.EncryptPath(name), mode, context)
+}
+
+func (fs *FS) GetXAttr(name string, attr string, context *fuse.Context) ([]byte, fuse.Status) {
+	return nil, fuse.ENOSYS
+}
+
+func (fs *FS) SetXAttr(name string, attr string, data []byte, flags int, context *fuse.Context) fuse.Status {
+	return fuse.ENOSYS
+}
+
+func (fs *FS) ListXAttr(name string, context *fuse.Context) ([]string, fuse.Status) {
+	return nil, fuse.ENOSYS
+}
+
+func (fs *FS) RemoveXAttr(name string, attr string, context *fuse.Context) fuse.Status {
+	return fuse.ENOSYS
+}