v2api/reverse: implement Lookup for gocryptfs.conf & gocryptfs.diriv

1 files changed, 53 insertions, 6 deletions

diff --git a/internal/fusefrontend_reverse/node.go b/internal/fusefrontend_reverse/node.go
index 8af7bed..0b2df12 100644
--- a/internal/fusefrontend_reverse/node.go
+++ b/internal/fusefrontend_reverse/node.go
@@ -9,6 +9,8 @@ import (
 	"github.com/hanwen/go-fuse/v2/fs"
 	"github.com/hanwen/go-fuse/v2/fuse"
 
+	"github.com/rfjakob/gocryptfs/internal/configfile"
+	"github.com/rfjakob/gocryptfs/internal/pathiv"
 	"github.com/rfjakob/gocryptfs/internal/syscallcompat"
 )
 
@@ -19,13 +21,56 @@ type Node struct {
 }
 
 // Lookup - FUSE call for discovering a file.
-// TODO handle virtual files
 func (n *Node) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (ch *fs.Inode, errno syscall.Errno) {
-	dirfd, pName, errno := n.prepareAtSyscall(name)
-	if errno != 0 {
+	dirfd := int(-1)
+	pName := ""
+	t := n.lookupFileType(name)
+	// gocryptfs.conf
+	if t == typeConfig {
+		var err error
+		rn := n.rootNode()
+		dirfd, err = syscallcompat.OpenDirNofollow(rn.args.Cipherdir, "")
+		if err != nil {
+			errno = fs.ToErrno(err)
+			return
+		}
+		defer syscall.Close(dirfd)
+		pName = configfile.ConfReverseName
+	} else if t == typeDiriv {
+		// gocryptfs.diriv
+		dirfd, pName, errno = n.prepareAtSyscall("")
+		if errno != 0 {
+			return
+		}
+		defer syscall.Close(dirfd)
+		st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
+		if err != nil {
+			errno = fs.ToErrno(err)
+			return
+		}
+		content := pathiv.Derive(n.Path(), pathiv.PurposeDirIV)
+		var vf *virtualFile
+		vf, errno = n.newVirtualFile(content, st, inoTagDirIV)
+		if errno != 0 {
+			return nil, errno
+		}
+		out.Attr = vf.attr
+		// Create child node
+		id := fs.StableAttr{Mode: uint32(vf.attr.Mode), Gen: 1, Ino: vf.attr.Ino}
+		ch = n.NewInode(ctx, vf, id)
 		return
+	} else if t == typeName {
+		// gocryptfs.longname.*.name
+
+		// TODO
+	} else if t == typeReal {
+		// real file
+		dirfd, pName, errno = n.prepareAtSyscall(name)
+		if errno != 0 {
+			return
+		}
+		defer syscall.Close(dirfd)
 	}
-	defer syscall.Close(dirfd)
 
 	// Get device number and inode number into `st`
 	st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
@@ -36,8 +81,10 @@ func (n *Node) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (ch
 	// Create new inode and fill `out`
 	ch = n.newChild(ctx, st, out)
 
-	// Translate ciphertext size in `out.Attr.Size` to plaintext size
-	n.translateSize(dirfd, pName, &out.Attr)
+	if t == typeReal {
+		// Translate ciphertext size in `out.Attr.Size` to plaintext size
+		n.translateSize(dirfd, pName, &out.Attr)
+	}
 
 	return ch, 0
 }