yuzu/src/core/hle/kernel/mutex.cpp
Yuri Kunde Schlesner 52f58e64ef Kernel: Make WaitObjects share ownership of Threads waiting on them
During normal operation, a thread waiting on an WaitObject and the
object hold mutual references to each other for the duration of the
wait.

If a process is forcefully terminated (The CTR kernel has a SVC to do
this, TerminateProcess, though no equivalent exists for threads.) its
threads would also be stopped and destroyed, leaving dangling pointers
in the WaitObjects.

The solution is to simply have the Thread remove itself from WaitObjects
when it is stopped. The vector of Threads in WaitObject has also been
changed to hold SharedPtrs, just in case. (Better to have a reference
cycle than a crash.)
2015-02-02 15:37:08 -02:00

88 lines
2.1 KiB
C++

// Copyright 2014 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <map>
#include <vector>
#include <boost/range/algorithm_ext/erase.hpp>
#include "common/common.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/mutex.h"
#include "core/hle/kernel/thread.h"
namespace Kernel {
/**
* Resumes a thread waiting for the specified mutex
* @param mutex The mutex that some thread is waiting on
*/
static void ResumeWaitingThread(Mutex* mutex) {
// Reset mutex lock thread handle, nothing is waiting
mutex->locked = false;
mutex->holding_thread = nullptr;
// Find the next waiting thread for the mutex...
auto next_thread = mutex->WakeupNextThread();
if (next_thread != nullptr) {
mutex->Acquire(next_thread);
}
}
void ReleaseThreadMutexes(Thread* thread) {
for (auto& mtx : thread->held_mutexes) {
ResumeWaitingThread(mtx.get());
}
thread->held_mutexes.clear();
}
Mutex::Mutex() {}
Mutex::~Mutex() {}
ResultVal<SharedPtr<Mutex>> Mutex::Create(bool initial_locked, std::string name) {
SharedPtr<Mutex> mutex(new Mutex);
// TOOD(yuriks): Don't create Handle (see Thread::Create())
CASCADE_RESULT(auto unused, Kernel::g_handle_table.Create(mutex));
mutex->initial_locked = initial_locked;
mutex->locked = false;
mutex->name = std::move(name);
mutex->holding_thread = nullptr;
// Acquire mutex with current thread if initialized as locked...
if (initial_locked)
mutex->Acquire();
return MakeResult<SharedPtr<Mutex>>(mutex);
}
bool Mutex::ShouldWait() {
return locked && holding_thread != GetCurrentThread();
}
void Mutex::Acquire() {
Acquire(GetCurrentThread());
}
void Mutex::Acquire(SharedPtr<Thread> thread) {
_assert_msg_(Kernel, !ShouldWait(), "object unavailable!");
if (locked)
return;
locked = true;
thread->held_mutexes.insert(this);
holding_thread = std::move(thread);
}
void Mutex::Release() {
if (!locked)
return;
holding_thread->held_mutexes.erase(this);
ResumeWaitingThread(this);
}
} // namespace