我正在使用fork()来实现一个TFTP服务器。如果我的服务器有20秒没有收到另一方的消息,我如何使用SIGALRM中止连接?
以下是我的代码:

while (1)
{
    pid = fork();
    if ( pid == -1 )
    {
        return EXIT_FAILURE;
    }

    if ( pid > 0 )
    {
        wait(NULL);
        close(server_socket);
    }
    else
    {
        do
        {
            n = recvfrom(server_socket, buffer, BUF_LEN, 0,
                         (struct sockaddr *)&sock_info, &sockaddr_len);
        }while(n > 0);
    }
}

最佳答案

使用alarm()设置计时器,计时器过期后使用sigaction()处理信号。

do
{
        struct sigaction s;
        s.sa_handler = handler; /* Establish the  signal handler */
        sigemptyset(&s.sa_mask);
        s.sa_flags = 0;
        alarm(20); /* first set the alarm of 20s */
        /* if within 20s server doesn't receive anthing, handler will be evoked */
        sigaction(SIGALRM, &s, NULL); /* when timer expires, handler will be called */
        n = recvfrom(server_socket, buffer, BUF_LEN, 0,
                        (struct sockaddr *)&sock_info, &sockaddr_len);
}while(n > 0);

调用处理程序后,中止服务器fd。
 static void handler(int sig) {
            /* send the SIGABRT to server process  */

 }

07-24 09:46
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