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// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
package utils
import (
"errors"
"fmt"
"io/fs"
"os"
"golang.org/x/sys/unix"
)
var _ = fmt.Print
func lock(fd, op int, path string) (err error) {
for {
err = unix.Flock(fd, op)
if !errors.Is(err, unix.EINTR) {
break
}
}
if err != nil {
opname := "exclusive flock()"
switch op {
case unix.LOCK_UN:
opname = "unlock flock()"
case unix.LOCK_SH:
opname = "shared flock()"
}
return &fs.PathError{
Op: opname,
Path: path,
Err: err,
}
}
return nil
}
func LockFileShared(f *os.File) error {
return lock(int(f.Fd()), unix.LOCK_SH, f.Name())
}
func LockFileExclusive(f *os.File) error {
return lock(int(f.Fd()), unix.LOCK_EX, f.Name())
}
func UnlockFile(f *os.File) error {
return lock(int(f.Fd()), unix.LOCK_UN, f.Name())
}
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