keywords: fix xattrs for broken symlinks

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

keywords_linux.go

@@ -59,6 +59,9 @@ var (
 			}
 			return strings.Join(klist, " "), nil
 		}
+		if !info.Mode().IsRegular() && !info.Mode().IsDir() {
+			return "", nil
+		}
 
 		xlist, err := xattr.List(path)
 		if err != nil {

keywords_linux_test.go

@@ -0,0 +1,79 @@
+// +build linux
+
+package mtree
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/vbatts/go-mtree/xattr"
+)
+
+func TestXattr(t *testing.T) {
+	// a bit dirty to create/destory a directory in cwd, but often /tmp is
+	// mounted tmpfs and doesn't support xattrs
+	dir, err := ioutil.TempDir(".", "test.xattrs.")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+	fh, err := os.Create(filepath.Join(dir, "file"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	fh.WriteString("howdy")
+	fh.Sync()
+	if _, err := fh.Seek(0, 0); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := os.Symlink("./no/such/path", filepath.Join(dir, "symlink")); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := xattr.Set(dir, "user.test", []byte("directory")); err != nil {
+		t.Skip(fmt.Sprintf("skipping: %q does not support xattrs", dir))
+	}
+	if err := xattr.Set(filepath.Join(dir, "file"), "user.test", []byte("regular file")); err != nil {
+		t.Fatal(err)
+	}
+
+	dirstat, err := os.Lstat(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Check the directory
+	str, err := xattrKeywordFunc(dir, dirstat, nil)
+	if err != nil {
+		t.Error(err)
+	}
+	if str == "" {
+		t.Errorf("expected a keyval; got %q", str)
+	}
+
+	filestat, err := fh.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Check the regular file
+	str, err = xattrKeywordFunc(filepath.Join(dir, "file"), filestat, fh)
+	if err != nil {
+		t.Error(err)
+	}
+	if str == "" {
+		t.Errorf("expected a keyval; got %q", str)
+	}
+
+	linkstat, err := os.Lstat(filepath.Join(dir, "symlink"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Check a broken symlink
+	_, err = xattrKeywordFunc(filepath.Join(dir, "symlink"), linkstat, nil)
+	if err != nil {
+		t.Error(err)
+	}
+}