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838d9fa251
Similar to Process, we need to make Thread refcounted. This will solve problems that will appear once we schedule threads on more than one processor. This allows us to hold onto threads without necessarily holding the scheduler lock for the entire duration.
126 lines
4.5 KiB
C++
126 lines
4.5 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <Kernel/Process.h>
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//#define PROCESS_DEBUG
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namespace Kernel {
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KResultOr<siginfo_t> Process::do_waitid(idtype_t idtype, int id, int options)
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{
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if (idtype == P_PID) {
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ScopedSpinLock lock(g_processes_lock);
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if (idtype == P_PID && !Process::from_pid(id))
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return KResult(-ECHILD);
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// FIXME: Race: After 'lock' releases, the 'id' process might vanish.
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// If that is not a problem, why check for it?
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// If it is a problem, let's fix it! (Eventually.)
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}
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ProcessID waitee_pid { 0 };
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// FIXME: WaitBlocker should support idtype/id specs directly.
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if (idtype == P_ALL) {
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waitee_pid = -1;
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} else if (idtype == P_PID) {
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waitee_pid = id;
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} else {
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// FIXME: Implement other PID specs.
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return KResult(-EINVAL);
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}
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if (Thread::current()->block<Thread::WaitBlocker>(nullptr, options, waitee_pid).was_interrupted())
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return KResult(-EINTR);
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ScopedSpinLock lock(g_processes_lock);
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// NOTE: If waitee was -1, m_waitee_pid will have been filled in by the scheduler.
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auto waitee_process = Process::from_pid(waitee_pid);
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if (!waitee_process)
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return KResult(-ECHILD);
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ASSERT(waitee_process);
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if (waitee_process->is_dead()) {
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return reap(*waitee_process);
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} else {
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// FIXME: PID/TID BUG
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// Make sure to hold the scheduler lock so that we operate on a consistent state
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ScopedSpinLock scheduler_lock(g_scheduler_lock);
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auto waitee_thread = Thread::from_tid(waitee_pid.value());
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if (!waitee_thread)
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return KResult(-ECHILD);
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ASSERT((options & WNOHANG) || waitee_thread->state() == Thread::State::Stopped);
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siginfo_t siginfo;
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memset(&siginfo, 0, sizeof(siginfo));
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siginfo.si_signo = SIGCHLD;
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siginfo.si_pid = waitee_process->pid().value();
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siginfo.si_uid = waitee_process->uid();
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switch (waitee_thread->state()) {
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case Thread::State::Stopped:
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siginfo.si_code = CLD_STOPPED;
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break;
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case Thread::State::Running:
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case Thread::State::Runnable:
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case Thread::State::Blocked:
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case Thread::State::Dying:
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case Thread::State::Dead:
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case Thread::State::Queued:
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siginfo.si_code = CLD_CONTINUED;
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break;
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default:
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ASSERT_NOT_REACHED();
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break;
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}
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siginfo.si_status = waitee_thread->m_stop_signal;
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return siginfo;
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}
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}
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pid_t Process::sys$waitid(Userspace<const Syscall::SC_waitid_params*> user_params)
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{
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REQUIRE_PROMISE(proc);
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Syscall::SC_waitid_params params;
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if (!copy_from_user(¶ms, user_params))
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return -EFAULT;
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#ifdef PROCESS_DEBUG
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dbg() << "sys$waitid(" << params.idtype << ", " << params.id << ", " << params.infop << ", " << params.options << ")";
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#endif
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auto siginfo_or_error = do_waitid(static_cast<idtype_t>(params.idtype), params.id, params.options);
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if (siginfo_or_error.is_error())
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return siginfo_or_error.error();
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if (!copy_to_user(params.infop, &siginfo_or_error.value()))
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return -EFAULT;
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return 0;
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}
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}
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