1// Copyright 2011 Evan Shaw. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// +build darwin dragonfly freebsd linux openbsd solaris netbsd
6
7package mmap
8
9import (
10	"golang.org/x/sys/unix"
11)
12
13func mmap(len int, inprot, inflags, fd uintptr, off int64) ([]byte, error) {
14	flags := unix.MAP_SHARED
15	prot := unix.PROT_READ
16	switch {
17	case inprot&COPY != 0:
18		prot |= unix.PROT_WRITE
19		flags = unix.MAP_PRIVATE
20	case inprot&RDWR != 0:
21		prot |= unix.PROT_WRITE
22	}
23	if inprot&EXEC != 0 {
24		prot |= unix.PROT_EXEC
25	}
26	if inflags&ANON != 0 {
27		flags |= unix.MAP_ANON
28	}
29
30	b, err := unix.Mmap(int(fd), off, len, prot, flags)
31	if err != nil {
32		return nil, err
33	}
34	return b, nil
35}
36
37func (m MMap) flush() error {
38	return unix.Msync([]byte(m), unix.MS_SYNC)
39}
40
41func (m MMap) lock() error {
42	return unix.Mlock([]byte(m))
43}
44
45func (m MMap) unlock() error {
46	return unix.Munlock([]byte(m))
47}
48
49func (m MMap) unmap() error {
50	return unix.Munmap([]byte(m))
51}
52