Merge release-20201019.0-34-g9ca66ec59 (automated)

3 files changed, 136 insertions, 0 deletions

diff --git a/pkg/refsvfs2/refs.go b/pkg/refsvfs2/refs.go
new file mode 100644
index 000000000..ef8beb659
--- /dev/null
+++ b/pkg/refsvfs2/refs.go
@@ -0,0 +1,36 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package refsvfs2 defines an interface for a reference-counted object.
+package refsvfs2
+
+import (
+	"gvisor.dev/gvisor/pkg/context"
+)
+
+// RefCounter is the interface to be implemented by objects that are reference
+// counted.
+type RefCounter interface {
+	// IncRef increments the reference counter on the object.
+	IncRef()
+
+	// DecRef decrements the object's reference count. Users of refs_template.Refs
+	// may specify a destructor to be called once the reference count reaches zero.
+	DecRef(ctx context.Context)
+
+	// TryIncRef attempts to increment the reference count, but may fail if all
+	// references have already been dropped, in which case it returns false. If
+	// true is returned, then a valid reference is now held on the object.
+	TryIncRef() bool
+}
diff --git a/pkg/refsvfs2/refs_map.go b/pkg/refsvfs2/refs_map.go
new file mode 100644
index 000000000..be75b0cc2
--- /dev/null
+++ b/pkg/refsvfs2/refs_map.go
@@ -0,0 +1,97 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package refsvfs2
+
+import (
+	"fmt"
+	"strings"
+
+	"gvisor.dev/gvisor/pkg/log"
+	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
+	"gvisor.dev/gvisor/pkg/sync"
+)
+
+// TODO(gvisor.dev/issue/1193): re-enable once kernfs refs are fixed.
+var ignored []string = []string{"kernfs.", "proc.", "sys.", "devpts.", "fuse."}
+
+var (
+	// liveObjects is a global map of reference-counted objects. Objects are
+	// inserted when leak check is enabled, and they are removed when they are
+	// destroyed. It is protected by liveObjectsMu.
+	liveObjects   map[CheckedObject]struct{}
+	liveObjectsMu sync.Mutex
+)
+
+// CheckedObject represents a reference-counted object with an informative
+// leak detection message.
+type CheckedObject interface {
+	// LeakMessage supplies a warning to be printed upon leak detection.
+	LeakMessage() string
+}
+
+func init() {
+	liveObjects = make(map[CheckedObject]struct{})
+}
+
+// LeakCheckEnabled returns whether leak checking is enabled. The following
+// functions should only be called if it returns true.
+func LeakCheckEnabled() bool {
+	return refs_vfs1.GetLeakMode() != refs_vfs1.NoLeakChecking
+}
+
+// Register adds obj to the live object map.
+func Register(obj CheckedObject, typ string) {
+	for _, str := range ignored {
+		if strings.Contains(typ, str) {
+			return
+		}
+	}
+	liveObjectsMu.Lock()
+	if _, ok := liveObjects[obj]; ok {
+		panic(fmt.Sprintf("Unexpected entry in leak checking map: reference %p already added", obj))
+	}
+	liveObjects[obj] = struct{}{}
+	liveObjectsMu.Unlock()
+}
+
+// Unregister removes obj from the live object map.
+func Unregister(obj CheckedObject, typ string) {
+	liveObjectsMu.Lock()
+	defer liveObjectsMu.Unlock()
+	if _, ok := liveObjects[obj]; !ok {
+		for _, str := range ignored {
+			if strings.Contains(typ, str) {
+				return
+			}
+		}
+		panic(fmt.Sprintf("Expected to find entry in leak checking map for reference %p", obj))
+	}
+	delete(liveObjects, obj)
+}
+
+// DoLeakCheck iterates through the live object map and logs a message for each
+// object. It is called once no reference-counted objects should be reachable
+// anymore, at which point anything left in the map is considered a leak.
+func DoLeakCheck() {
+	liveObjectsMu.Lock()
+	defer liveObjectsMu.Unlock()
+	leaked := len(liveObjects)
+	if leaked > 0 {
+		log.Warningf("Leak checking detected %d leaked objects:", leaked)
+		for obj := range liveObjects {
+			log.Warningf(obj.LeakMessage())
+		}
+	}
+}
diff --git a/pkg/refsvfs2/refsvfs2_state_autogen.go b/pkg/refsvfs2/refsvfs2_state_autogen.go
new file mode 100644
index 000000000..ca5fbb104
--- /dev/null
+++ b/pkg/refsvfs2/refsvfs2_state_autogen.go
@@ -0,0 +1,3 @@
+// automatically generated by stateify.
+
+package refsvfs2