v2api/reverse: implement Lookup for longname

1 files changed, 41 insertions, 0 deletions

diff --git a/internal/fusefrontend_reverse/root_node.go b/internal/fusefrontend_reverse/root_node.go
index 726380f..4297ecf 100644
--- a/internal/fusefrontend_reverse/root_node.go
+++ b/internal/fusefrontend_reverse/root_node.go
@@ -1,10 +1,19 @@
 package fusefrontend_reverse
 
 import (
+	"log"
+	"strings"
+	"syscall"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/hanwen/go-fuse/v2/fs"
+
 	"github.com/rfjakob/gocryptfs/internal/contentenc"
 	"github.com/rfjakob/gocryptfs/internal/fusefrontend"
 	"github.com/rfjakob/gocryptfs/internal/inomap"
 	"github.com/rfjakob/gocryptfs/internal/nametransform"
+	"github.com/rfjakob/gocryptfs/internal/syscallcompat"
 
 	"github.com/sabhiram/go-gitignore"
 )
@@ -37,3 +46,35 @@ func NewRootNode(args fusefrontend.Args, c *contentenc.ContentEnc, n nametransfo
 		excluder:      prepareExcluder(args),
 	}
 }
+
+// You can pass either gocryptfs.longname.XYZ.name or gocryptfs.longname.XYZ.
+func (rn *RootNode) findLongnameParent(fd int, diriv []byte, longname string) (pName string, cFullName string, errno syscall.Errno) {
+	if strings.HasSuffix(longname, nametransform.LongNameSuffix) {
+		longname = nametransform.RemoveLongNameSuffix(longname)
+	}
+	entries, err := syscallcompat.Getdents(fd)
+	if err != nil {
+		errno = fs.ToErrno(err)
+		return
+	}
+	for _, entry := range entries {
+		if len(entry.Name) <= shortNameMax {
+			continue
+		}
+		cFullName = rn.nameTransform.EncryptName(entry.Name, diriv)
+		if len(cFullName) <= unix.NAME_MAX {
+			// Entry should have been skipped by the "continue" above
+			log.Panic("logic error or wrong shortNameMax constant?")
+		}
+		hName := rn.nameTransform.HashLongName(cFullName)
+		if longname == hName {
+			pName = entry.Name
+			break
+		}
+	}
+	if pName == "" {
+		errno = syscall.ENOENT
+		return
+	}
+	return
+}