Filesystems shouldn't be saving references to Platform.

Platform objects are not savable, storing references to them in
filesystem datastructures would cause save to fail if someone actually
passed in a Platform.

Current implementations work because everywhere a Platform is
expected, we currently pass in a Kernel object which embeds Platform
and thus satisfies the interface.

Eliminate this indirection and save pointers to Kernel directly.

PiperOrigin-RevId: 225288336
Change-Id: Ica399ff43f425e15bc150a0d7102196c3d54a2ab

2 files changed, 55 insertions, 0 deletions

diff --git a/pkg/sentry/kernel/contexttest/BUILD b/pkg/sentry/kernel/contexttest/BUILD
new file mode 100644
index 000000000..391986291
--- /dev/null
+++ b/pkg/sentry/kernel/contexttest/BUILD
@@ -0,0 +1,17 @@
+package(licenses = ["notice"])  # Apache 2.0
+
+load("//tools/go_stateify:defs.bzl", "go_library")
+
+go_library(
+    name = "contexttest",
+    testonly = 1,
+    srcs = ["contexttest.go"],
+    importpath = "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/contexttest",
+    visibility = ["//pkg/sentry:internal"],
+    deps = [
+        "//pkg/sentry/context",
+        "//pkg/sentry/context/contexttest",
+        "//pkg/sentry/kernel",
+        "//pkg/sentry/platform",
+    ],
+)
diff --git a/pkg/sentry/kernel/contexttest/contexttest.go b/pkg/sentry/kernel/contexttest/contexttest.go
new file mode 100644
index 000000000..9eb18e7e8
--- /dev/null
+++ b/pkg/sentry/kernel/contexttest/contexttest.go
@@ -0,0 +1,38 @@
+// Copyright 2018 Google LLC
+//
+// 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 contexttest provides a test context.Context which includes
+// a dummy kernel pointing to a valid platform.
+package contexttest
+
+import (
+	"testing"
+
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/context/contexttest"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/platform"
+)
+
+// Context returns a Context that may be used in tests. Uses ptrace as the
+// platform.Platform, and provides a stub kernel that only serves to point to
+// the platform.
+func Context(tb testing.TB) context.Context {
+	ctx := contexttest.Context(tb)
+	k := &kernel.Kernel{
+		Platform: platform.FromContext(ctx),
+	}
+	ctx.(*contexttest.TestContext).RegisterValue(kernel.CtxKernel, k)
+	return ctx
+}