125
vendor/go.etcd.io/etcd/pkg/fileutil/lock_windows.go
generated
vendored
Normal file
125
vendor/go.etcd.io/etcd/pkg/fileutil/lock_windows.go
generated
vendored
Normal file
@@ -0,0 +1,125 @@
|
||||
// Copyright 2015 The etcd 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
|
||||
|
||||
package fileutil
|
||||
|
||||
import (
|
||||
"errors"
|
||||
"fmt"
|
||||
"os"
|
||||
"syscall"
|
||||
"unsafe"
|
||||
)
|
||||
|
||||
var (
|
||||
modkernel32 = syscall.NewLazyDLL("kernel32.dll")
|
||||
procLockFileEx = modkernel32.NewProc("LockFileEx")
|
||||
|
||||
errLocked = errors.New("The process cannot access the file because another process has locked a portion of the file.")
|
||||
)
|
||||
|
||||
const (
|
||||
// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365203(v=vs.85).aspx
|
||||
LOCKFILE_EXCLUSIVE_LOCK = 2
|
||||
LOCKFILE_FAIL_IMMEDIATELY = 1
|
||||
|
||||
// see https://msdn.microsoft.com/en-us/library/windows/desktop/ms681382(v=vs.85).aspx
|
||||
errLockViolation syscall.Errno = 0x21
|
||||
)
|
||||
|
||||
func TryLockFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
|
||||
f, err := open(path, flag, perm)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
if err := lockFile(syscall.Handle(f.Fd()), LOCKFILE_FAIL_IMMEDIATELY); err != nil {
|
||||
f.Close()
|
||||
return nil, err
|
||||
}
|
||||
return &LockedFile{f}, nil
|
||||
}
|
||||
|
||||
func LockFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
|
||||
f, err := open(path, flag, perm)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
if err := lockFile(syscall.Handle(f.Fd()), 0); err != nil {
|
||||
f.Close()
|
||||
return nil, err
|
||||
}
|
||||
return &LockedFile{f}, nil
|
||||
}
|
||||
|
||||
func open(path string, flag int, perm os.FileMode) (*os.File, error) {
|
||||
if path == "" {
|
||||
return nil, fmt.Errorf("cannot open empty filename")
|
||||
}
|
||||
var access uint32
|
||||
switch flag {
|
||||
case syscall.O_RDONLY:
|
||||
access = syscall.GENERIC_READ
|
||||
case syscall.O_WRONLY:
|
||||
access = syscall.GENERIC_WRITE
|
||||
case syscall.O_RDWR:
|
||||
access = syscall.GENERIC_READ | syscall.GENERIC_WRITE
|
||||
case syscall.O_WRONLY | syscall.O_CREAT:
|
||||
access = syscall.GENERIC_ALL
|
||||
default:
|
||||
panic(fmt.Errorf("flag %v is not supported", flag))
|
||||
}
|
||||
fd, err := syscall.CreateFile(&(syscall.StringToUTF16(path)[0]),
|
||||
access,
|
||||
syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE,
|
||||
nil,
|
||||
syscall.OPEN_ALWAYS,
|
||||
syscall.FILE_ATTRIBUTE_NORMAL,
|
||||
0)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return os.NewFile(uintptr(fd), path), nil
|
||||
}
|
||||
|
||||
func lockFile(fd syscall.Handle, flags uint32) error {
|
||||
var flag uint32 = LOCKFILE_EXCLUSIVE_LOCK
|
||||
flag |= flags
|
||||
if fd == syscall.InvalidHandle {
|
||||
return nil
|
||||
}
|
||||
err := lockFileEx(fd, flag, 1, 0, &syscall.Overlapped{})
|
||||
if err == nil {
|
||||
return nil
|
||||
} else if err.Error() == errLocked.Error() {
|
||||
return ErrLocked
|
||||
} else if err != errLockViolation {
|
||||
return err
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func lockFileEx(h syscall.Handle, flags, locklow, lockhigh uint32, ol *syscall.Overlapped) (err error) {
|
||||
var reserved uint32 = 0
|
||||
r1, _, e1 := syscall.Syscall6(procLockFileEx.Addr(), 6, uintptr(h), uintptr(flags), uintptr(reserved), uintptr(locklow), uintptr(lockhigh), uintptr(unsafe.Pointer(ol)))
|
||||
if r1 == 0 {
|
||||
if e1 != 0 {
|
||||
err = error(e1)
|
||||
} else {
|
||||
err = syscall.EINVAL
|
||||
}
|
||||
}
|
||||
return err
|
||||
}
|
||||
Reference in New Issue
Block a user