Tools/TestWebKitAPI/Tests/WTF/Signals.cpp

/*
 * Copyright (C) 2017-2023 Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer in the
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 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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#include "config.h"

#include <type_traits>
#include <wtf/DataLog.h>
#include <wtf/Threading.h>
#include <wtf/WTFConfig.h>
#if OS(UNIX)
#include <signal.h>
#else
#include <wtf/Gigacage.h>
#include <wtf/OSAllocator.h>
#endif

#if OS(UNIX)
class ReflectedThread : public Thread {
public:
    using Thread::m_mutex;
    using Thread::m_handle;
    using Thread::hasExited;
};

TEST(Signals, SignalsWorkOnExit)
{
    static bool handlerRan = false;
    addSignalHandler(Signal::Usr, [] (Signal signal, SigInfo&, PlatformRegisters&) -> SignalAction {
        RELEASE_ASSERT(signal == Signal::Usr);

        handlerRan = true;
        return SignalAction::Handled;
    });
    activateSignalHandlersFor(Signal::Usr);
    WTF::Config::finalize();

    Atomic<bool> receiverShouldKeepRunning(true);
    Ref<Thread> receiverThread = (Thread::create("ThreadMessage receiver"_s,
        [&receiverShouldKeepRunning] () {
            while (receiverShouldKeepRunning.load()) { }
    }));

    bool signalFired;
    {
        std::unique_lock<WordLock> locker(static_cast<ReflectedThread&>(receiverThread.get()).m_mutex);
        receiverShouldKeepRunning.store(false);
        EXPECT_FALSE(static_cast<ReflectedThread&>(receiverThread.get()).hasExited());
        sleep(1_s);
        signalFired = !pthread_kill(static_cast<ReflectedThread&>(receiverThread.get()).m_handle, SIGUSR2);
    }

    receiverThread->waitForCompletion();
    EXPECT_TRUE(handlerRan || !signalFired);
}
#else
TEST(Signals, SignalsAccessFault)
{
    static bool handlerRan = false;
    addSignalHandler(Signal::AccessFault, [] (Signal signal, SigInfo& sigInfo, PlatformRegisters& context) -> SignalAction {
        RELEASE_ASSERT(signal == Signal::AccessFault);

        handlerRan = true;
#if CPU(ARM)
        context.Pc += 2;
#elif CPU(X86)
        context.Eip += 3;
#elif CPU(X86_64)
        context.Rip += 3;
#else
#error Unsupported CPU
#endif

        return SignalAction::Handled;
    });
    activateSignalHandlersFor(Signal::AccessFault);
    WTF::Config::finalize();

    // Allocate a page of memory
    char* ptr = std::bit_cast<char*>(Gigacage::tryAllocateZeroedVirtualPages(Gigacage::Primitive, 4096));

    // Protect that page - 4096 bytes, not readable or writeable
    OSAllocator::protect(ptr, 4096, false, false);

    // Try and read, triggering an AccessFault
    dataLogLn("Reading from protected memory", static_cast<unsigned>(ptr[0]));

    EXPECT_TRUE(handlerRan);
}
#endif