ladybird/Kernel/Syscalls/disown.cpp
Tom 4bbee00650 Kernel: disown should unblock any potential waiters
This is necessary because if a process changes the state to Stopped
or resumes from that state, a wait entry is created in the parent
process. So, if a child process does this before disown is called,
we need to clear those entries to avoid leaking references/zombies
that won't be cleaned up until the former parent exits.

This also should solve an even more unlikely corner case where another
thread is waiting on a pid that is being disowned by another thread.
2020-12-12 21:28:12 +01:00

43 lines
1.7 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/Process.h>
namespace Kernel {
int Process::sys$disown(ProcessID pid)
{
REQUIRE_PROMISE(proc);
auto process = Process::from_pid(pid);
if (!process)
return -ESRCH;
if (process->ppid() != this->pid())
return -ECHILD;
process->m_ppid = 0;
process->disowned_by_waiter(*this);
return 0;
}
}