fusefrontend: make GetXAttr() symlink-safe on Linux

Uses the /proc/self/fd trick, which does not work
on Darwin.

1 files changed, 18 insertions, 1 deletions

diff --git a/internal/fusefrontend/xattr_darwin.go b/internal/fusefrontend/xattr_darwin.go
index b626006..cf48d13 100644
--- a/internal/fusefrontend/xattr_darwin.go
+++ b/internal/fusefrontend/xattr_darwin.go
@@ -3,7 +3,11 @@
 // Package fusefrontend interfaces directly with the go-fuse library.
 package fusefrontend
 
-import "github.com/pkg/xattr"
+import (
+	"github.com/pkg/xattr"
+
+	"github.com/hanwen/go-fuse/fuse"
+)
 
 func disallowedXAttrName(attr string) bool {
 	return false
@@ -13,3 +17,16 @@ func disallowedXAttrName(attr string) bool {
 func filterXattrSetFlags(flags int) int {
 	return flags &^ xattr.XATTR_NOSECURITY
 }
+
+// This function is NOT symlink-safe because Darwin lacks fgetxattr().
+func (fs *FS) getXattr(relPath string, cAttr string, context *fuse.Context) ([]byte, fuse.Status) {
+	cPath, err := fs.getBackingPath(relPath)
+	if err != nil {
+		return nil, fuse.ToStatus(err)
+	}
+	cData, err := xattr.LGet(cPath, cAttr)
+	if err != nil {
+		return nil, unpackXattrErr(err)
+	}
+	return cData, fuse.OK
+}