From 48961d27a8bcc76b3783a7cc4a4a5ebcd5532d25 Mon Sep 17 00:00:00 2001
From: Jamie Liu <jamieliu@google.com>
Date: Fri, 7 Jun 2019 14:51:18 -0700
Subject: Move //pkg/sentry/memutil to //pkg/memutil.

PiperOrigin-RevId: 252124156
---
 pkg/memutil/memutil_unsafe.go | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 pkg/memutil/memutil_unsafe.go

(limited to 'pkg/memutil/memutil_unsafe.go')

diff --git a/pkg/memutil/memutil_unsafe.go b/pkg/memutil/memutil_unsafe.go
new file mode 100644
index 000000000..979d942a9
--- /dev/null
+++ b/pkg/memutil/memutil_unsafe.go
@@ -0,0 +1,42 @@
+// Copyright 2018 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.
+
+// +build linux
+
+// Package memutil provides a wrapper for the memfd_create() system call.
+package memutil
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// CreateMemFD creates a memfd file and returns the fd.
+func CreateMemFD(name string, flags int) (int, error) {
+	p, err := syscall.BytePtrFromString(name)
+	if err != nil {
+		return -1, err
+	}
+	fd, _, e := syscall.Syscall(unix.SYS_MEMFD_CREATE, uintptr(unsafe.Pointer(p)), uintptr(flags), 0)
+	if e != 0 {
+		if e == syscall.ENOSYS {
+			return -1, fmt.Errorf("memfd_create(2) is not implemented. Check that you have Linux 3.17 or higher")
+		}
+		return -1, e
+	}
+	return int(fd), nil
+}
-- 
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