Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

pkg/sentry/uniqueid/BUILD

@@ -0,0 +1,11 @@
+package(licenses = ["notice"])  # Apache 2.0
+
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "uniqueid",
+    srcs = ["context.go"],
+    importpath = "gvisor.googlesource.com/gvisor/pkg/sentry/uniqueid",
+    visibility = ["//pkg/sentry:internal"],
+    deps = ["//pkg/sentry/context"],
+)

pkg/sentry/uniqueid/context.go

@@ -0,0 +1,44 @@
+// Copyright 2018 Google Inc.
+//
+// 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 uniqueid defines context.Context keys for obtaining system-wide
+// unique identifiers.
+package uniqueid
+
+import (
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+)
+
+// contextID is the kernel package's type for context.Context.Value keys.
+type contextID int
+
+const (
+	// CtxGlobalUniqueID is a Context.Value key for a system-wide
+	// unique identifier.
+	CtxGlobalUniqueID contextID = iota
+
+	// CtxInotifyCookie is a Context.Value key for a unique inotify
+	// event cookie.
+	CtxInotifyCookie
+)
+
+// GlobalFromContext returns a system-wide unique identifier from ctx.
+func GlobalFromContext(ctx context.Context) uint64 {
+	return ctx.Value(CtxGlobalUniqueID).(uint64)
+}
+
+// InotifyCookie generates a unique inotify event cookie from ctx.
+func InotifyCookie(ctx context.Context) uint32 {
+	return ctx.Value(CtxInotifyCookie).(uint32)
+}