6 files changed, 62 insertions, 0 deletions
diff --git a/back/cmd/authfs/authfs.go b/back/cmd/authfs/authfs.go
index 71e5128..bf6e340 100644
--- a/back/cmd/authfs/authfs.go
+++ b/back/cmd/authfs/authfs.go
@@ -12,6 +12,7 @@ import (
 
 type File interface {
 	Qid() (p9.QID, error)
+	Open(mode p9.Mode) error
 	// TODO
 }
 
@@ -121,3 +122,35 @@ func (fs *Authfs) attach(fid p9.FID, f File) error {
 	fs.files[fid] = f
 	return nil
 }
+
+func (fs *Authfs) Rclunk(fid p9.FID) error {
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+
+	if _, exists := fs.files[fid]; !exists {
+		return ErrFidNotExist
+	}
+	delete(fs.files, fid)
+	return nil
+}
+
+func (fs *Authfs) Ropen(fid p9.FID, mode p9.Mode) (p9.QID, error) {
+	f, err := fs.getFile(fid)
+	if err != nil {
+		return p9.QID{}, err
+	}
+	if err := f.Open(mode); err != nil {
+		return p9.QID{}, err
+	}
+	return f.Qid()
+}
+
+func (fs *Authfs) getFile(fid p9.FID) (File, error) {
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	f, exists := fs.files[fid]
+	if !exists {
+		return nil, ErrFidNotExist
+	}
+	return f, nil
+}
diff --git a/back/cmd/authfs/err.go b/back/cmd/authfs/err.go
index 81da2ba..4f4dbbf 100644
--- a/back/cmd/authfs/err.go
+++ b/back/cmd/authfs/err.go
@@ -7,4 +7,5 @@ var (
 	ErrFileNotExist = errors.New("file does not exist")
 	ErrFidExist     = errors.New("fid already exists")
 	ErrFidNotExist  = errors.New("fid does not exist")
+	ErrPerm         = errors.New("permission denied")
 )
diff --git a/back/cmd/authfs/root.go b/back/cmd/authfs/root.go
index 5d56045..7a0fcbd 100644
--- a/back/cmd/authfs/root.go
+++ b/back/cmd/authfs/root.go
@@ -29,3 +29,10 @@ func (r *RootDir) Qid() (p9.QID, error) {
 		Path:    rootQidPath,
 	}, nil
 }
+
+func (r *RootDir) Open(mode p9.Mode) error {
+	if mode != p9.OREAD {
+		return ErrPerm
+	}
+	return nil
+}
diff --git a/back/cmd/authfs/sess.go b/back/cmd/authfs/sess.go
index 3d0cca3..ce45ae4 100644
--- a/back/cmd/authfs/sess.go
+++ b/back/cmd/authfs/sess.go
@@ -52,3 +52,10 @@ func (s *Session) Extend() bool {
 }
 
 func (s *Session) Qid() (p9.QID, error) { return s.qid, nil }
+
+func (s *Session) Open(mode p9.Mode) error {
+	if mode != p9.OREAD {
+		return ErrPerm
+	}
+	return nil
+}
diff --git a/back/cmd/authfs/sessdir.go b/back/cmd/authfs/sessdir.go
index eafc92f..22d8202 100644
--- a/back/cmd/authfs/sessdir.go
+++ b/back/cmd/authfs/sessdir.go
@@ -72,3 +72,10 @@ func (dir *SessionsDir) Qid() (p9.QID, error) {
 		Path:    sessionsQidPath,
 	}, nil
 }
+
+func (dir *SessionsDir) Open(mode p9.Mode) error {
+	if mode&(p9.OEXEC|p9.OTRUNC|p9.ORCLOSE) != 0 {
+		return ErrPerm
+	}
+	return nil
+}
diff --git a/back/cmd/authfs/userdir.go b/back/cmd/authfs/userdir.go
index f7ef5a7..d5e1cce 100644
--- a/back/cmd/authfs/userdir.go
+++ b/back/cmd/authfs/userdir.go
@@ -49,3 +49,10 @@ func (dir *UsersDir) Qid() (p9.QID, error) {
 		Path:    usersQidPath,
 	}, nil
 }
+
+func (dir *UsersDir) Open(mode p9.Mode) error {
+	if mode&(p9.OEXEC|p9.OTRUNC|p9.ORCLOSE) != 0 {
+		return ErrPerm
+	}
+	return nil
+}