| // Copyright 2019 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package ld |
| |
| import ( |
| "reflect" |
| "syscall" |
| "unsafe" |
| ) |
| |
| func (out *OutBuf) Mmap(filesize uint64) error { |
| err := out.f.Truncate(int64(filesize)) |
| if err != nil { |
| Exitf("resize output file failed: %v", err) |
| } |
| |
| low, high := uint32(filesize), uint32(filesize>>32) |
| fmap, err := syscall.CreateFileMapping(syscall.Handle(out.f.Fd()), nil, syscall.PAGE_READWRITE, high, low, nil) |
| if err != nil { |
| return err |
| } |
| defer syscall.CloseHandle(fmap) |
| |
| ptr, err := syscall.MapViewOfFile(fmap, syscall.FILE_MAP_READ|syscall.FILE_MAP_WRITE, 0, 0, uintptr(filesize)) |
| if err != nil { |
| return err |
| } |
| *(*reflect.SliceHeader)(unsafe.Pointer(&out.buf)) = reflect.SliceHeader{Data: ptr, Len: int(filesize), Cap: int(filesize)} |
| return nil |
| } |
| |
| func (out *OutBuf) munmap() { |
| if out.buf == nil { |
| return |
| } |
| // Apparently unmapping without flush may cause ACCESS_DENIED error |
| // (see issue 38440). |
| err := syscall.FlushViewOfFile(uintptr(unsafe.Pointer(&out.buf[0])), 0) |
| if err != nil { |
| Exitf("FlushViewOfFile failed: %v", err) |
| } |
| err = syscall.UnmapViewOfFile(uintptr(unsafe.Pointer(&out.buf[0]))) |
| out.buf = nil |
| if err != nil { |
| Exitf("UnmapViewOfFile failed: %v", err) |
| } |
| } |
