Move flipcall.packetWindowMmap to memutil.

PiperOrigin-RevId: 381100861

pkg/flipcall/BUILD

@@ -10,9 +10,7 @@ go_library(
         "flipcall_unsafe.go",
         "futex_linux.go",
         "io.go",
-        "packet_window_allocator.go",
-        "packet_window_mmap_amd64.go",
-        "packet_window_mmap_arm64.go",
+        "packet_window.go",
     ],
     visibility = ["//visibility:public"],
     deps = [

pkg/flipcall/flipcall.go

@@ -22,6 +22,7 @@ import (
 	"sync/atomic"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/memutil"
 )
 
 // An Endpoint provides the ability to synchronously transfer data and control
@@ -96,9 +97,9 @@ func (ep *Endpoint) Init(side EndpointSide, pwd PacketWindowDescriptor, opts ...
 	if pwd.Length > math.MaxUint32 {
 		return fmt.Errorf("packet window size (%d) exceeds maximum (%d)", pwd.Length, math.MaxUint32)
 	}
-	m, e := packetWindowMmap(pwd)
-	if e != 0 {
-		return fmt.Errorf("failed to mmap packet window: %v", e)
+	m, err := memutil.MapFile(0, uintptr(pwd.Length), unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED, uintptr(pwd.FD), uintptr(pwd.Offset))
+	if err != nil {
+		return fmt.Errorf("failed to mmap packet window: %v", err)
 	}
 	ep.packet = m
 	ep.dataCap = uint32(pwd.Length) - uint32(PacketHeaderBytes)

pkg/flipcall/packet_window_mmap_amd64.go

@@ -1,23 +0,0 @@
-// 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 flipcall
-
-import "golang.org/x/sys/unix"
-
-// Return a memory mapping of the pwd in memory that can be shared outside the sandbox.
-func packetWindowMmap(pwd PacketWindowDescriptor) (uintptr, unix.Errno) {
-	m, _, err := unix.RawSyscall6(unix.SYS_MMAP, 0, uintptr(pwd.Length), unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED, uintptr(pwd.FD), uintptr(pwd.Offset))
-	return m, err
-}

pkg/flipcall/packet_window_mmap_arm64.go

@@ -1,25 +0,0 @@
-// 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.
-
-// +build arm64
-
-package flipcall
-
-import "golang.org/x/sys/unix"
-
-// Return a memory mapping of the pwd in memory that can be shared outside the sandbox.
-func packetWindowMmap(pwd PacketWindowDescriptor) (uintptr, unix.Errno) {
-	m, _, err := unix.RawSyscall6(unix.SYS_MMAP, 0, uintptr(pwd.Length), unix.PROT_READ|unix.PROT_WRITE, unix.MAP_SHARED, uintptr(pwd.FD), uintptr(pwd.Offset))
-	return m, err
-}