go-ethereum/vendor/github.com/prometheus/tsdb/fileutil/mmap_unix.go

// Copyright 2017 The Prometheus 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 !windows,!plan9

package fileutil

import (
	"os"

	"golang.org/x/sys/unix"
)

func mmap(f *os.File, length int) ([]byte, error) {
	return unix.Mmap(int(f.Fd()), 0, length, unix.PROT_READ, unix.MAP_SHARED)
}

func munmap(b []byte) (err error) {
	return unix.Munmap(b)
}