Question

以下是一些代码示例，但问题是当使用'putty'在串行线上发送'break'时，信号处理程序不。

#include <sys/ioctl.h>
#include <termios.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/signal.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>

void signal_handler(int status);

int main(void)
{
    FILE* f = fopen("/dev/ttyS0", "r+b");

    struct sigaction saio; /* definition of signal action */
    saio.sa_handler = signal_handler;
    // saio.sa_mask = 0;
    saio.sa_flags = 0;
    saio.sa_restorer = NULL;
    sigaction(SIGINT,&saio,NULL);

    struct termios options;

    tcgetattr (fileno(f), &options);

    cfsetispeed(&options, B9600);
    cfsetospeed(&options, B9600);

    options.c_iflag &= ~IGNBRK; // & ~IGNPAR;
    options.c_iflag |= BRKINT; // | PARMRK | INPCK;
    options.c_cc[VMIN] = 0;
    options.c_cc[VTIME] = 1;

    if (tcsetattr(fileno(f), TCSAFLUSH, &options) == -1)
    {
        printf("port setup failure\n");
        return -1;
    }

    ioctl(fileno(f), TIOCSCTTY, (char *)NULL);
    while (1) {
        int ch = fgetc(f);
        switch (ch) {
        case EOF: break;
        case EAGAIN: printf("[EAGAIN]"); break;
        case EBADF: printf("[EBADF]"); break;
        case EINTR: printf("[EINTR]"); break;
        case EIO: printf("[EIO]"); break;
        case EOVERFLOW: printf("[EOVERFLOW]"); break;
        default:
            if (isprint(ch))
                putchar(ch);
            else
                printf("[%02x]", ch);
        }
    }
}

void signal_handler(int status)
{
    printf("received SIGINT %d signal.\n", status);
    exit(0);
}

以下是我的设置：

user@dev:~/$ sudo stty -F /dev/ttyS0
speed 9600 baud; line = 0;
intr = <undef>; quit = <undef>; erase = <undef>; kill = <undef>; eof = <undef>; start = <undef>; stop = <undef>; susp = <undef>; rprnt = <undef>; werase = <undef>;
lnext = <undef>; flush = <undef>; min = 0; time = 1;
-imaxbel
-opost -onlcr
-icanon -iexten -echo -echoe -echok -echoctl -echoke

我缺少什么/为什么我没有收到信号？我正在使用USB-2-Serial转换器，我可以看到中断发送，但在此客户端根本没有触发。

Answer 1

在strace监督下试一试。在tcgetattr之后添加对tcsetattr的来电，并检查您要求的所有更改是否已完成你也应该在获得一个新的之前摆脱你的控制权。根据man tty-ioctl：

   Controlling tty
       TIOCSCTTY int arg
              Make  the given tty the controlling tty of the calling process.  The calling process must be a session leader and not have a controlling tty already.  If
              this tty is already the controlling tty of a different session group then the ioctl fails with EPERM, unless the caller is root  and  arg  equals  1,  in
              which case the tty is stolen, and all processes that had it as controlling tty lose it.

       TIOCNOTTY void
              If  the  given tty was the controlling tty of the calling process, give up this controlling tty.  If the process was session leader, then send SIGHUP and
              SIGCONT to the foreground process group and all processes in the current session lose their controlling tty.

在Linux中的/ dev / tty设备上处理用户中断（UART中断）

1 个答案: