44 lines
1.2 KiB
Go
44 lines
1.2 KiB
Go
// SPDX-License-Identifier: MIT
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//go:build unix
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package helper
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import (
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"errors"
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"fmt"
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"os"
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"path/filepath"
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"syscall"
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)
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// lockState serialises concurrent apply/remove operations using an advisory
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// file lock stored next to the state file. It returns a release function that
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// must always be called (typically deferred); its error reports a release that
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// failed, which the caller should surface.
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func lockState(statePath string) (func() error, error) {
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dir := filepath.Dir(statePath)
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if err := os.MkdirAll(dir, 0o755); err != nil {
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return nil, fmt.Errorf("create %s: %w", dir, err)
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}
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path := filepath.Join(dir, "prx.lock")
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f, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0o600)
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if err != nil {
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return nil, fmt.Errorf("open lock %s: %w", path, err)
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}
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if err := syscall.Flock(int(f.Fd()), syscall.LOCK_EX); err != nil {
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_ = f.Close()
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return nil, fmt.Errorf("lock %s: %w", path, err)
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}
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return func() error {
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var errs []error
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if err := syscall.Flock(int(f.Fd()), syscall.LOCK_UN); err != nil {
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errs = append(errs, fmt.Errorf("unlock %s: %w", path, err))
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}
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if err := f.Close(); err != nil {
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errs = append(errs, fmt.Errorf("close %s: %w", path, err))
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}
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return errors.Join(errs...)
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}, nil
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}
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