Pfft, crashes are for chumps

Diabolical.c

static jmp_buf jmpEnv;

enum {
    kPrepareBinaryAddress = 0x44dd,
    kMutexBinaryAddress = 0x9090
};

void signal_handler(int n, siginfo_t *info, void *context)
{
    longjmp(jmpEnv, 1);
}

static int hwc_wrap_prepare(hwc_composer_device_1_t *dev, size_t numDisplays, hwc_display_contents_1_t **displays)
{
    if (numDisplays == 0) {
        return 0;
    }

    int result = 0;

    struct sigaction oldAction;
    struct sigaction action;

    memset(&oldAction, 0, sizeof(struct sigaction));
    memset(&action, 0, sizeof(struct sigaction));

    sigemptyset(&action.sa_mask);
    action.sa_sigaction = signal_handler;
    action.sa_flags = SA_RESTART | SA_SIGINFO;

    // Use the alternate signal stack if available so we can catch stack overflows.
    action.sa_flags |= SA_ONSTACK;

    sigaction(SIGSEGV, &action, &oldAction);

    if (setjmp(jmpEnv)) {
        // One of the first/last things prepare() does it lock/unlock a mutex. We're going to assume we failed whilst the mutex was locked.
        // So let's unlock it... using crazy hacks.
        pthread_mutex_t *mstarHwcMutex = (pthread_mutex_t *)((size_t)dev->wrapper.device->prepare - kPrepareBinaryAddress + kMutexBinaryAddress);
        pthread_mutex_unlock(mstarHwcMutex);
    } else {
        result = dev->wrapper.device->prepare(dev->wrapper.device, numDisplays, displays);

        if (result != 0) {
            ALOGE("hwc_wrap_prepare - numDisplays: %d - Failed with error: %d", numDisplays, result);
        }
    }

    // Restore original SIGSEGV handler
    sigaction(SIGSEGV, &oldAction, NULL);

    return result;
}