66 lines
1.8 KiB
Go
66 lines
1.8 KiB
Go
// Copyright 2026 Alibaba Group
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//go:build windows
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package lock
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import (
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"errors"
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"os"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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const (
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lockfileExclusiveLock = 0x00000002
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lockfileFailImmediately = 0x00000001
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// Keep the mandatory Windows lock outside the PID payload at the start
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// of the file. LockFileEx byte-range locks block reads through a second
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// handle, so locking byte zero made bus status unable to read the holder
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// PID while the daemon was running.
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lockfileLockOffset = 1 << 30
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)
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func lockFile(f *os.File) error {
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handle := windows.Handle(f.Fd())
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ol := &windows.Overlapped{Offset: lockfileLockOffset}
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return windows.LockFileEx(
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handle,
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lockfileExclusiveLock|lockfileFailImmediately,
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0,
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1,
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0,
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(*windows.Overlapped)(unsafe.Pointer(ol)),
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)
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}
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func unlockFile(f *os.File) {
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handle := windows.Handle(f.Fd())
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ol := &windows.Overlapped{Offset: lockfileLockOffset}
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_ = windows.UnlockFileEx(
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handle,
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0,
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1,
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0,
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(*windows.Overlapped)(unsafe.Pointer(ol)),
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)
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}
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func isBusy(err error) bool {
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// LockFileEx with LOCKFILE_FAIL_IMMEDIATELY returns ERROR_LOCK_VIOLATION
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// when the region is already locked.
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return errors.Is(err, windows.ERROR_LOCK_VIOLATION) || errors.Is(err, windows.ERROR_IO_PENDING)
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}
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