mirror of
https://github.com/prometheus/prometheus.git
synced 2024-11-15 18:14:06 -08:00
47 lines
1.4 KiB
Go
47 lines
1.4 KiB
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.
|
|
|
|
package fileutil
|
|
|
|
import (
|
|
"os"
|
|
"syscall"
|
|
"unsafe"
|
|
)
|
|
|
|
func mmap(f *os.File, size int) ([]byte, error) {
|
|
low, high := uint32(size), uint32(size>>32)
|
|
h, errno := syscall.CreateFileMapping(syscall.Handle(f.Fd()), nil, syscall.PAGE_READONLY, high, low, nil)
|
|
if h == 0 {
|
|
return nil, os.NewSyscallError("CreateFileMapping", errno)
|
|
}
|
|
|
|
addr, errno := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, uintptr(size))
|
|
if addr == 0 {
|
|
return nil, os.NewSyscallError("MapViewOfFile", errno)
|
|
}
|
|
|
|
if err := syscall.CloseHandle(syscall.Handle(h)); err != nil {
|
|
return nil, os.NewSyscallError("CloseHandle", err)
|
|
}
|
|
|
|
return (*[maxMapSize]byte)(unsafe.Pointer(addr))[:size], nil
|
|
}
|
|
|
|
func munmap(b []byte) error {
|
|
if err := syscall.UnmapViewOfFile((uintptr)(unsafe.Pointer(&b[0]))); err != nil {
|
|
return os.NewSyscallError("UnmapViewOfFile", err)
|
|
}
|
|
return nil
|
|
}
|