Check in gVisor.

PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

3 files changed, 65 insertions, 0 deletions

diff --git a/pkg/sentry/memutil/BUILD b/pkg/sentry/memutil/BUILD
new file mode 100644
index 000000000..a387a0c9f
--- /dev/null
+++ b/pkg/sentry/memutil/BUILD
@@ -0,0 +1,14 @@
+package(licenses = ["notice"])  # Apache 2.0
+
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "memutil",
+    srcs = [
+        "memutil.go",
+        "memutil_unsafe.go",
+    ],
+    importpath = "gvisor.googlesource.com/gvisor/pkg/sentry/memutil",
+    visibility = ["//pkg/sentry:internal"],
+    deps = ["@org_golang_x_sys//unix:go_default_library"],
+)
diff --git a/pkg/sentry/memutil/memutil.go b/pkg/sentry/memutil/memutil.go
new file mode 100644
index 000000000..4f245cf3c
--- /dev/null
+++ b/pkg/sentry/memutil/memutil.go
@@ -0,0 +1,16 @@
+// 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 memutil contains the utility functions for memory operations.
+package memutil
diff --git a/pkg/sentry/memutil/memutil_unsafe.go b/pkg/sentry/memutil/memutil_unsafe.go
new file mode 100644
index 000000000..32c27eb2f
--- /dev/null
+++ b/pkg/sentry/memutil/memutil_unsafe.go
@@ -0,0 +1,35 @@
+// 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 memutil
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// CreateMemFD creates a memfd file and returns the fd.
+func CreateMemFD(name string, flags int) (fd int, err error) {
+	p, err := syscall.BytePtrFromString(name)
+	if err != nil {
+		return -1, err
+	}
+	r0, _, e0 := syscall.Syscall(unix.SYS_MEMFD_CREATE, uintptr(unsafe.Pointer(p)), uintptr(flags), 0)
+	if e0 != 0 {
+		return -1, e0
+	}
+	return int(r0), nil
+}