Merge pull request #10223 from giuseppe/improve-rootless-automatic-range-split

rootless: improve automatic range split

pkg/rootless/rootless.go

@@ -137,7 +137,7 @@ func GetAvailableGids() (int64, error) {
 // It assumes availableMappings is sorted by ID.
 func findIDInMappings(id int64, availableMappings []user.IDMap) *user.IDMap {
 	i := sort.Search(len(availableMappings), func(i int) bool {
-		return availableMappings[i].ID >= id
+		return availableMappings[i].ID <= id
 	})
 	if i < 0 || i >= len(availableMappings) {
 		return nil
@@ -157,7 +157,7 @@ func MaybeSplitMappings(mappings []spec.LinuxIDMapping, availableMappings []user
 	overflow.Size = 0
 	consumed := 0
 	sort.Slice(availableMappings, func(i, j int) bool {
-		return availableMappings[i].ID < availableMappings[j].ID
+		return availableMappings[i].ID > availableMappings[j].ID
 	})
 	for {
 		cur := overflow

pkg/rootless/rootless_test.go

@@ -98,4 +98,61 @@ func TestMaybeSplitMappings(t *testing.T) {
 	if !reflect.DeepEqual(newMappings, desiredMappings) {
 		t.Fatal("wrong mappings generated")
 	}
+
+	mappings = []spec.LinuxIDMapping{
+		{
+			ContainerID: 0,
+			HostID:      0,
+			Size:        4,
+		},
+	}
+	desiredMappings = []spec.LinuxIDMapping{
+		{
+			ContainerID: 0,
+			HostID:      0,
+			Size:        1,
+		},
+		{
+			ContainerID: 1,
+			HostID:      1,
+			Size:        1,
+		},
+		{
+			ContainerID: 2,
+			HostID:      2,
+			Size:        1,
+		},
+		{
+			ContainerID: 3,
+			HostID:      3,
+			Size:        1,
+		},
+	}
+	availableMappings = []user.IDMap{
+		{
+			ID:       0,
+			ParentID: 0,
+			Count:    1,
+		},
+		{
+			ID:       1,
+			ParentID: 1,
+			Count:    1,
+		},
+		{
+			ID:       2,
+			ParentID: 2,
+			Count:    1,
+		},
+		{
+			ID:       3,
+			ParentID: 3,
+			Count:    1,
+		},
+	}
+
+	newMappings = MaybeSplitMappings(mappings, availableMappings)
+	if !reflect.DeepEqual(newMappings, desiredMappings) {
+		t.Fatal("wrong mappings generated")
+	}
 }