pre-unlock — 路径解锁尝试的通知。
The pre-unlock hook runs whenever
someone attempts to remove a lock on a file. It can be used
to create policies that specify which users are allowed to
unlock particular paths. It's particularly important for
determining policies about lock breakage. If user A locks a
file, is user B allowed to break the lock? What if the lock
is more than a week old? These sorts of things can be
decided and enforced by the hook.
If the pre-unlock hook program
returns a nonzero exit value, the unlock action is aborted
and anything printed to stderr is marshalled back to the
client.