path: root/vendor/github.com/edsrzf/mmap-go/mmap_unix.go

// Copyright 2011 Evan Shaw. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build darwin dragonfly freebsd linux openbsd solaris netbsd

package mmap

import (
    "syscall"
)

func mmap(len int, inprot, inflags, fd uintptr, off int64) ([]byte, error) {
    flags := syscall.MAP_SHARED
    prot := syscall.PROT_READ
    switch {
    case inprot&COPY != 0:
        prot |= syscall.PROT_WRITE
        flags = syscall.MAP_PRIVATE
    case inprot&RDWR != 0:
        prot |= syscall.PROT_WRITE
    }
    if inprot&EXEC != 0 {
        prot |= syscall.PROT_EXEC
    }
    if inflags&ANON != 0 {
        flags |= syscall.MAP_ANON
    }

    b, err := syscall.Mmap(int(fd), off, len, prot, flags)
    if err != nil {
        return nil, err
    }
    return b, nil
}

func flush(addr, len uintptr) error {
    _, _, errno := syscall.Syscall(_SYS_MSYNC, addr, len, _MS_SYNC)
    if errno != 0 {
        return syscall.Errno(errno)
    }
    return nil
}

func lock(addr, len uintptr) error {
    _, _, errno := syscall.Syscall(syscall.SYS_MLOCK, addr, len, 0)
    if errno != 0 {
        return syscall.Errno(errno)
    }
    return nil
}

func unlock(addr, len uintptr) error {
    _, _, errno := syscall.Syscall(syscall.SYS_MUNLOCK, addr, len, 0)
    if errno != 0 {
        return syscall.Errno(errno)
    }
    return nil
}

func unmap(addr, len uintptr) error {
    _, _, errno := syscall.Syscall(syscall.SYS_MUNMAP, addr, len, 0)
    if errno != 0 {
        return syscall.Errno(errno)
    }
    return nil
}