39 lines
939 B
Go
39 lines
939 B
Go
//go:build !windows
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package instance
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import (
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"errors"
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"os"
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"syscall"
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)
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type unixInstanceLock struct {
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file *os.File
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}
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// tryAcquireInstanceLock 用 flock 非阻塞独占锁文件。
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// 第二个参数表示「锁被别的进程持有」，此时调用方应继续扫描下一个槽位。
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func tryAcquireInstanceLock(path string) (instanceLock, bool, error) {
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file, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0o600)
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if err != nil {
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return nil, false, err
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}
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if err := syscall.Flock(int(file.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
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_ = file.Close()
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if errors.Is(err, syscall.EWOULDBLOCK) || errors.Is(err, syscall.EAGAIN) {
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return nil, false, nil
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}
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return nil, false, err
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}
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return &unixInstanceLock{file: file}, true, nil
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}
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func (l *unixInstanceLock) Close() error {
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if l == nil || l.file == nil {
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return nil
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}
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_ = syscall.Flock(int(l.file.Fd()), syscall.LOCK_UN)
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return l.file.Close()
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}
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