c - sigwait() 和信号处理程序

Question

如果我为 SIGABRT 设置和发出信号处理程序，同时我有一个线程在 sigwait() 上等待 SIGABRT 到来(我在其他线程中有一个被 pthread_sigmask 阻塞的 SIGABRT)。

那么先处理哪一个呢？信号处理程序或 sigwait() ？

[我面临一些问题，sigwait() 永远被阻止。我目前正在调试它]

main()
{
    sigset_t                    signal_set;

    sigemptyset(&signal_set);
    sigaddset(&signal_set, SIGABRT); 
    sigprocmask(SIG_BLOCK, &signal_set, NULL); 

    // Dont deliver SIGABORT while running this thread and it's kids.
    pthread_sigmask(SIG_BLOCK, &signal_set, NULL);

    pthread_create(&tAbortWaitThread, NULL, WaitForAbortThread, NULL);
    ..
    Create all other threads
    ...
}   

static void*    WaitForAbortThread(void* v)
{
    sigset_t signal_set;
    int stat;
    int sig;

    sigfillset( &signal_set);
    pthread_sigmask( SIG_BLOCK, &signal_set, NULL ); // Dont want any signals


    sigemptyset(&signal_set);
    sigaddset(&signal_set, SIGABRT);     // Add only SIGABRT

    // This thread while executing , will handle the SIGABORT signal via signal handler.
    pthread_sigmask(SIG_UNBLOCK, &signal_set, NULL); 
    stat= sigwait( &signal_set, &sig  ); // lets wait for signal handled in CatchAbort().
    while (stat == -1)
    {
        stat= sigwait( &signal_set, &sig  );
    }

    TellAllThreadsWeAreGoingDown();

    sleep(10);

    return null;
}

// Abort signal handler executed via sigaction().
static void CatchAbort(int i, siginfo_t* info, void* v)
{
    sleep(20); // Dont return , hold on till the other threads are down.
}

在 sigwait() 处，我将知道已收到 SIGABRT。我会告诉其他线程。然后将持有中止信号处理程序，以便进程不会终止。

我想知道 sigwait() 和信号处理程序的交互。

Answer 1

来自 sigwait() 文档:

The sigwait() function suspends execution of the calling thread until one of the signals specified in the signal set becomes pending.

挂起信号是指等待传递给线程/进程之一的阻塞信号。因此，您需要不要像您对pthread_sigmask(SIG_UNBLOCK, &signal_set, NULL) 调用那样解锁信号。

这应该有效:

static void* WaitForAbortThread(void* v){
    sigset_t signal_set;

    sigemptyset(&signal_set);
    sigaddset(&signal_set, SIGABRT); 

    sigwait( &signal_set, &sig  );

    TellAllThreadsWeAreGoingDown();

    sleep(10);

    return null;
}