嗨，我正在为此硬件编码，使用信号（sigaction，sigprocmask）

Question

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <time.h>

unsigned time_duration;
int num_count=0;

void sig_handling(int sig){
    if(sig==SIGINT){
        num_count++;
        printf("The number of SIGINT signals are %d\n", num_count);
    }
 } 


int main(int argc, char *argv[])
{
    unsigned time_stamp1=(unsigned)time(NULL);
    time_stamp1=time_stamp1+30;
    sigset_t newmask;
    sigset_t oldmask;
    sigset_t pendmask;
    struct sigaction act;
    act.sa_handler=&sig_handling;
act.sa_flags=SA_RESTART;
sigaction(SIGINT, &act, NULL);
while(1){
    unsigned time_stamp2=(unsigned)time(NULL);
    time_duration=time_stamp1-time_stamp2;
    if(time_duration>20&&time_duration<30)
    {
        sigemptyset(&newmask);
        sigaddset(&newmask, SIGINT);
    }
    if(time_duration>10&&time_duration<20)
    {
        sigprocmask(SIG_BLOCK, &newmask, &oldmask);
    }
    if(time_duration>0&&time_duration<10)
    {
        sigpending(&pendmask);
        sigprocmask(SIG_SETMASK, &oldmask, NULL);
        
    }
    if(time_duration==0)
    {
        break;
    }
}
return 0;

}

要求是计算并打印在前 10 秒内接收到的 SIGINT 信号的数量，一旦达到 10 秒就“阻止”SIGINT 信号，一旦达到 20 秒就“取消阻止”和“忽略”SIGINT 信号它的生命，在 30 秒后终止。

只有前 10 秒有效。 第二个 10 秒似乎不算 SIGINT（我不确定如何“忽略”信号）。 要求是使用sigaction和sigpromask 。

Answer 1

我已经修复了我的热门评论中提到的问题。

time_duration从 30倒数到 0。但是，如果它从 0 倒数到30，它会更接近问题陈述[并使逻辑更容易]。 所以，从这里开始，我将参考那个区间

在 10-20 间隔中，您设置newmask ，但直到 20-30 间隔才在sigprocmask中使用它。 我认为你应该立即使用口罩。

在 20-30 间隔，我们必须恢复原始掩码，但我们需要另一个sigaction调用， sa_handler设置为SIG_IGN

你有sigpending(&pendmsk); 但不要对它做任何事情[而且它并不是真正需要的]。

由于我在顶级评论中提到的信号安全要求，所有打印都应该在信号处理程序之外完成。 而且，这需要在num_count上使用volatile [因此基本级别将使用最新值]。

---

我添加了一个标志，允许在进入新的间隔/时代时执行一次给定的操作。

我添加了一个kill系统调用来模拟用户执行ctrl-c并将信号更改为SIGTERM ，因此真正的SIGINT将终止程序 [方便调试]。 您可以将其还原为生产。

我更改了一些变量名称以更具描述性。

这是重构的代码：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <time.h>

time_t time_duration;
volatile long long num_count = 0;

#define SIGSELF     SIGTERM

void
sig_handling(int sig)
{
    if (sig == SIGSELF) {
        num_count++;
#if 0
        printf("The number of SIGINT signals are %d\n", num_count);
#endif
    }
}

int
main(int argc, char **argv)
{

    time_t time_begin = time(NULL);

    sigset_t newmask;
    sigset_t oldmask;
    struct sigaction act;

#if 1
    sigaction(SIGSELF,NULL,&act);
#endif
    act.sa_handler = sig_handling;
    act.sa_flags = SA_RESTART;
    sigaction(SIGSELF, &act, NULL);

    pid_t pid = getpid();
    time_t time_msg = -1;

    long long kill_count = 0;

    int interval_count[10] = { 0 };

    while (1) {
        kill(pid,SIGSELF);
        ++kill_count;

        time_t time_current = time(NULL);
        time_duration = time_current - time_begin;

        if (time_duration != time_msg) {
            time_msg = time_duration;
            printf("At %ld seconds the number of signals are %lld",
                time_duration,num_count);
            printf(" (kills %lld)",kill_count);
            printf("\n");
        }

        time_t time_switch = time_duration / 10;

        int curstate = interval_count[time_switch];

        if (curstate == 0)
            printf("New interval %ld\n",time_switch);

        switch (time_switch) {
        case 0:  // 0-10
            break;

        case 1:  // 10-20
            if (curstate == 0) {
                sigemptyset(&newmask);
                sigaddset(&newmask, SIGSELF);
                sigprocmask(SIG_BLOCK, &newmask, &oldmask);
            }
            break;

        case 2:  // 20-30
            if (curstate == 0) {
                act.sa_handler = SIG_IGN;
                sigaction(SIGSELF, &act, NULL);
                sigprocmask(SIG_SETMASK, &oldmask, NULL);
            }
            break;
        }

        interval_count[time_switch] = curstate + 1;

        if (time_duration > 30)
            break;
    }

    return 0;
}

---

这是程序 output：

At 0 seconds the number of signals are 1 (kills 1)
New interval 0
At 1 seconds the number of signals are 487973 (kills 487973)
At 2 seconds the number of signals are 1021629 (kills 1021629)
At 3 seconds the number of signals are 1560710 (kills 1560710)
At 4 seconds the number of signals are 2100419 (kills 2100419)
At 5 seconds the number of signals are 2647694 (kills 2647694)
At 6 seconds the number of signals are 3192151 (kills 3192151)
At 7 seconds the number of signals are 3731573 (kills 3731573)
At 8 seconds the number of signals are 4273751 (kills 4273751)
At 9 seconds the number of signals are 4817509 (kills 4817509)
At 10 seconds the number of signals are 5360348 (kills 5360348)
New interval 1
At 11 seconds the number of signals are 5360348 (kills 6948004)
At 12 seconds the number of signals are 5360348 (kills 8523401)
At 13 seconds the number of signals are 5360348 (kills 10074263)
At 14 seconds the number of signals are 5360348 (kills 11432598)
At 15 seconds the number of signals are 5360348 (kills 12950546)
At 16 seconds the number of signals are 5360348 (kills 14533591)
At 17 seconds the number of signals are 5360348 (kills 15990611)
At 18 seconds the number of signals are 5360348 (kills 17410250)
At 19 seconds the number of signals are 5360348 (kills 18986650)
At 20 seconds the number of signals are 5360348 (kills 20552985)
New interval 2
At 21 seconds the number of signals are 5360348 (kills 22138819)
At 22 seconds the number of signals are 5360348 (kills 23743963)
At 23 seconds the number of signals are 5360348 (kills 25265593)
At 24 seconds the number of signals are 5360348 (kills 26802154)
At 25 seconds the number of signals are 5360348 (kills 28349228)
At 26 seconds the number of signals are 5360348 (kills 29926249)
At 27 seconds the number of signals are 5360348 (kills 31509756)
At 28 seconds the number of signals are 5360348 (kills 33100829)
At 29 seconds the number of signals are 5360348 (kills 34688121)
At 30 seconds the number of signals are 5360348 (kills 36274367)
New interval 3
At 31 seconds the number of signals are 5360348 (kills 37870874)