From ac5a911c64a30d5d29c9f9d9cd2930dca30270d3 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <me@cschwarz.com>
Date: Sun, 30 Apr 2017 16:13:05 +0200
Subject: [PATCH] zfs: glob mapping for complete wildcard ("*")

---
 zfs/mapping_test.go | 14 ++++++++++++++
 zfs/zfs.go          | 23 +++++++++++++++++++----
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/zfs/mapping_test.go b/zfs/mapping_test.go
index a1a741d..038fbb0 100644
--- a/zfs/mapping_test.go
+++ b/zfs/mapping_test.go
@@ -27,6 +27,20 @@ func TestGlobMapping(t *testing.T) {
 
 }
 
+func TestGlobMappingWildcard(t *testing.T) {
+	m := GlobMapping{
+		PrefixPath: EmptyDatasetPath,
+		TargetRoot: toDatasetPath("backups/share1"),
+	}
+
+	var r DatasetPath
+	var err error
+	r, err = m.Map(toDatasetPath("tank/usr/home"))
+
+	assert.Equal(t, toDatasetPath("backups/share1/tank/usr/home"), r)
+	assert.NoError(t, err)
+}
+
 func TestComboMapping(t *testing.T) {
 
 	m1 := GlobMapping{
diff --git a/zfs/zfs.go b/zfs/zfs.go
index ad2764e..1d38643 100644
--- a/zfs/zfs.go
+++ b/zfs/zfs.go
@@ -35,7 +35,16 @@ func (p DatasetPath) ToString() string {
 	return strings.Join(p, "/")
 }
 
+func (p DatasetPath) Empty() bool {
+	return len(p) == 0
+}
+
+var EmptyDatasetPath DatasetPath = []string{}
+
 func NewDatasetPath(s string) (p DatasetPath, err error) {
+	if s == "" {
+		return EmptyDatasetPath, nil // the empty dataset path
+	}
 	// TODO validation
 	return toDatasetPath(s), nil
 }
@@ -60,11 +69,17 @@ var ZFS_BINARY string = "zfs"
 func zfsList(root string, filter DatasetFilter) (datasets []DatasetPath, err error) {
 
 	const ZFS_LIST_FIELD_COUNT = 1
-
-	cmd := exec.Command(ZFS_BINARY, "list", "-H", "-r",
+	args := make([]string, 0, 10)
+	args = append(args,
+		"list", "-H", "-r",
 		"-t", "filesystem,volume",
-		"-o", "name",
-		root)
+		"-o", "name")
+
+	if len(root) > 0 {
+		args = append(args, root)
+	}
+
+	cmd := exec.Command(ZFS_BINARY, args...)
 
 	var stdout io.Reader
 	var stderr io.Reader