fusefrontend: only compile getBackingPath() on Darwin

This function is NOT symlink-safe. Darwin needs it because it lacks
fgetxattr(2) and friends.

internal/fusefrontend/names.go

@@ -31,21 +31,6 @@ func (fs *FS) isFiltered(path string) bool {
 	return false
 }
 
-// GetBackingPath - get the absolute encrypted path of the backing file
-// from the relative plaintext path "relPath"
-//
-// TODO: this function is NOT symlink-safe.
-// TODO: Move to xattr_darwin.go.
-func (fs *FS) getBackingPath(relPath string) (string, error) {
-	cPath, err := fs.encryptPath(relPath)
-	if err != nil {
-		return "", err
-	}
-	cAbsPath := filepath.Join(fs.args.Cipherdir, cPath)
-	tlog.Debug.Printf("getBackingPath: %s + %s -> %s", fs.args.Cipherdir, relPath, cAbsPath)
-	return cAbsPath, nil
-}
-
 // openBackingDir opens the parent ciphertext directory of plaintext path
 // "relPath" and returns the dirfd and the encrypted basename.
 //

internal/fusefrontend/xattr_darwin.go

@@ -4,9 +4,13 @@
 package fusefrontend
 
 import (
+	"path/filepath"
+
 	"github.com/pkg/xattr"
 
 	"github.com/hanwen/go-fuse/fuse"
+
+	"github.com/rfjakob/gocryptfs/internal/tlog"
 )
 
 func disallowedXAttrName(attr string) bool {
@@ -67,3 +71,18 @@ func (fs *FS) listXAttr(relPath string, context *fuse.Context) ([]string, fuse.S
 	}
 	return cNames, fuse.OK
 }
+
+// getBackingPath - get the absolute encrypted path of the backing file
+// from the relative plaintext path "relPath"
+//
+// This function is NOT symlink-safe. Darwin needs it because it lacks
+// fgetxattr(2) and friends.
+func (fs *FS) getBackingPath(relPath string) (string, error) {
+	cPath, err := fs.encryptPath(relPath)
+	if err != nil {
+		return "", err
+	}
+	cAbsPath := filepath.Join(fs.args.Cipherdir, cPath)
+	tlog.Debug.Printf("getBackingPath: %s + %s -> %s", fs.args.Cipherdir, relPath, cAbsPath)
+	return cAbsPath, nil
+}