Move flipcall.packetWindowMmap to memutil.

PiperOrigin-RevId: 381100861

4 files changed, 50 insertions, 2 deletions

diff --git a/pkg/memutil/BUILD b/pkg/memutil/BUILD
index 9d07d98b4..bea595286 100644
--- a/pkg/memutil/BUILD
+++ b/pkg/memutil/BUILD
@@ -4,7 +4,11 @@ package(licenses = ["notice"])
 
 go_library(
     name = "memutil",
-    srcs = ["memutil_unsafe.go"],
+    srcs = [
+        "memfd_linux_unsafe.go",
+        "memutil.go",
+        "mmap.go",
+    ],
     visibility = ["//visibility:public"],
     deps = ["@org_golang_x_sys//unix:go_default_library"],
 )
diff --git a/pkg/memutil/memutil_unsafe.go b/pkg/memutil/memfd_linux_unsafe.go
index 6676d1ce3..504382213 100644
--- a/pkg/memutil/memutil_unsafe.go
+++ b/pkg/memutil/memfd_linux_unsafe.go
@@ -14,7 +14,6 @@
 
 // +build linux
 
-// Package memutil provides a wrapper for the memfd_create() system call.
 package memutil
 
 import (
diff --git a/pkg/memutil/memutil.go b/pkg/memutil/memutil.go
new file mode 100644
index 000000000..3185882fd
--- /dev/null
+++ b/pkg/memutil/memutil.go
@@ -0,0 +1,16 @@
+// 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.
+
+// Package memutil provides utilities for working with shared memory files.
+package memutil
diff --git a/pkg/memutil/mmap.go b/pkg/memutil/mmap.go
new file mode 100644
index 000000000..7c939293f
--- /dev/null
+++ b/pkg/memutil/mmap.go
@@ -0,0 +1,29 @@
+// 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 memutil
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+// MapFile returns a memory mapping configured by the given options as per
+// mmap(2).
+func MapFile(addr, len, prot, flags, fd, offset uintptr) (uintptr, error) {
+	m, _, e := unix.RawSyscall6(unix.SYS_MMAP, addr, len, prot, flags, fd, offset)
+	if e != 0 {
+		return 0, e
+	}
+	return m, nil
+}