mirror of
https://github.com/J3vb/OwnCord.git
synced 2026-09-03 03:50:00 +03:00
35 lines
1.2 KiB
Go
35 lines
1.2 KiB
Go
|
//go:build linux || darwin
|
||
|
|
|
||
|
|
package db
|
||
|
|
|
||
|
|
import (
|
||
|
|
"errors"
|
||
|
|
"os"
|
||
|
|
"syscall"
|
||
|
|
)
|
||
|
|
|
||
|
|
// tryLockFile takes a non-blocking exclusive flock on path. The lock is tied
|
||
|
|
// to the open descriptor, so it vanishes with the process no matter how it
|
||
|
|
// dies — there is no stale-lock failure mode.
|
||
|
|
func tryLockFile(path string) (func(), error) {
|
||
|
|
f, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0o600) //nolint:gosec // sidecar of the configured db path
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
if err := syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil { //nolint:gosec // G115: fd of a just-opened file is far below int range
|
||
|
|
_ = f.Close()
|
||
|
|
if errors.Is(err, syscall.EWOULDBLOCK) || errors.Is(err, syscall.EAGAIN) {
|
||
|
|
return nil, errAlreadyLocked
|
||
|
|
}
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
return func() {
|
||
|
|
// Unlock before close is redundant (close releases flock) but keeps
|
||
|
|
// the intent explicit. The file itself is left behind on purpose:
|
||
|
|
// removing it opens an inode-swap race with a concurrent acquirer,
|
||
|
|
// and a leftover zero-byte .lock file is harmless.
|
||
|
|
_ = syscall.Flock(int(f.Fd()), syscall.LOCK_UN) //nolint:gosec // G115: same fd as above
|
||
|
|
_ = f.Close()
|
||
|
|
}, nil
|
||
|
|
}
|