1 files changed, 52 insertions, 0 deletions
diff --git a/internal/fusefrontend/node_helpers.go b/internal/fusefrontend/node_helpers.go
index a31a41d..ad92043 100644
--- a/internal/fusefrontend/node_helpers.go
+++ b/internal/fusefrontend/node_helpers.go
@@ -2,6 +2,7 @@ package fusefrontend
 
 import (
 	"context"
+	"path/filepath"
 	"syscall"
 
 	"github.com/hanwen/go-fuse/v2/fs"
@@ -63,3 +64,54 @@ func (n *Node) translateSize(dirfd int, cName string, out *fuse.Attr) {
 		out.Size = uint64(len(target))
 	}
 }
+
+// Path returns the relative plaintext path of this node
+func (n *Node) Path() string {
+	return n.Inode.Path(n.Root())
+}
+
+// rootNode returns the Root Node of the filesystem.
+func (n *Node) rootNode() *RootNode {
+	return n.Root().Operations().(*RootNode)
+}
+
+// prepareAtSyscall returns a (dirfd, cName) pair that can be used
+// with the "___at" family of system calls (openat, fstatat, unlinkat...) to
+// access the backing encrypted directory.
+//
+// If you pass a `child` file name, the (dirfd, cName) pair will refer to
+// a child of this node.
+// If `child` is empty, the (dirfd, cName) pair refers to this node itself.
+func (n *Node) prepareAtSyscall(child string) (dirfd int, cName string, errno syscall.Errno) {
+	p := n.Path()
+	if child != "" {
+		p = filepath.Join(p, child)
+	}
+	rn := n.rootNode()
+	if rn.isFiltered(p) {
+		errno = syscall.EPERM
+		return
+	}
+	dirfd, cName, err := rn.openBackingDir(p)
+	if err != nil {
+		errno = fs.ToErrno(err)
+	}
+	return
+}
+
+// newChild attaches a new child inode to n.
+// The passed-in `st` will be modified to get a unique inode number.
+func (n *Node) newChild(ctx context.Context, st *syscall.Stat_t, out *fuse.EntryOut) *fs.Inode {
+	// Get unique inode number
+	rn := n.rootNode()
+	rn.inoMap.TranslateStat(st)
+	out.Attr.FromStat(st)
+	// Create child node
+	id := fs.StableAttr{
+		Mode: uint32(st.Mode),
+		Gen:  1,
+		Ino:  st.Ino,
+	}
+	node := &Node{}
+	return n.NewInode(ctx, node, id)
+}