Question

我有一个必须使用Ctrl-C或SIGINT终止的进程。在这种情况下，我不能在键盘上使用Ctrl-C，因此必须在C中使用kill命令。此代码基本上读取GPIO输入并启动和停止脚本record.sh，即GStreamer命令行脚本。

我只想终止在startVideoRecording（）中创建的子进程。我需要按照我喜欢的方式多次开始，停止，开始，停止录制。这不是一次性的事情。

但是，当我更改gpio值并触发stopAllRecordings（）时，它不会将SIGINT发送到子进程。只是挂在那里＆＃34;向GStreamer进程发送中断..状态0＆＃34;

如何确保使用Ctrl-C等效的视频录制过程终止？

感谢。

以下是代码：

int main() {
    pollGPIOSwitch(&vn200);
}


void* pollGPIOSwitch(void* arg) {


   Vn200* vn200 = (Vn200*)arg;
   int fd;
   char buf[100];
   char value; 
   int videoRecError;
   bool videoRecOn = false;

   sprintf(buf, "/sys/class/gpio/gpio56/value");

   while (KEEP_GOING) {
       fd = open(buf,O_RDONLY);
       lseek(fd,0,SEEK_SET); // move to beginning of file
       read(fd,&value,1);
       if (value=='0') {
           if (videoRecOn) { // recording on, switch off, end recording
               stopAllRecordings();
               videoRecOn = false;
               TriggerGPSINSThreadExit = 0; // reset variables
               printf("Reset GPSINS Thread variables.\n");
           }
       }
       else if (!videoRecOn) { // recording off, switch on, start recording
            if (pthread_create(&GPSINSLoggingThread, NULL, runGPSINS,(void*) vn200) != 0) {
                printf("Error: Fail to create runGPSINS thread\n");
            }

            videoRecError = startVideoRecording();
            if (videoRecError == -1)
                pthread_exit(&videoRecError);
            videoRecOn = true; 
       }
       usleep(500000);
   }
   close(fd);


   printf("Exited Polling!");
}

int startVideoRecording() {
    int error;
    error = 0;

    if ((AVRecordingProcess = fork()) != -1) {
        switch (AVRecordingProcess) {
            case -1:
                printf("Error: Fail to create AVRecordingProcess\n");
                error = -1;
            case 0:
                execl("record.sh", "0", NULL);
                //system("//root//record.sh");
                printf("Error: Fail to execute AVRecordingProcess\n");
                error = -1;
            default:
               printf("Video Recording...process id %d\n", AVRecordingProcess); 
                break;
        }
    } else {  
        printf("Error: MainHost failed to fork AVRecordingProcess\n");
        error = -1;
    } 

    return error;

}


void stopAllRecordings() {
    int ret; 
    FILE *infile, *outfile;
    int ch;


    printf("Terminating child processes..%d\n", AVRecordingProcess);
    ret = kill(AVRecordingProcess, SIGINT);
    printf("Sending interrupt to GStreamer process.. Status %d\n", ret);

    int status;
    printf("Wait for the GStreamer process %d to end....", AVRecordingProcess);
    wait(AVRecordingProcess);
    printf("GStreamer ended.\n"); 
}

Answer 1

您是否可能正在启动多个子进程并且只将SIGINT发送到您创建的最后一个子进程而不是之前的进程？输入“PS”并在启动此程序后按Enter键，查看已启动的进程数。

Answer 2

我最终做到了这一点：

int startVideoRecording() {
    int error;
    error = 0;

    if ((AVRecordingProcess = fork()) != -1) {
        switch (AVRecordingProcess) {
            case -1:
                printf("Error: Fail to create AVRecordingProcess\n");
                error = -1;
            case 0:
                setpgid(AVRecordingProcess,0);  <-- NEW
                execl("record.sh", "0", NULL);
                //system("//root//record.sh");
                printf("Error: Fail to execute AVRecordingProcess\n");
                error = -1;
            default:
               printf("Video Recording...process id %d\n", AVRecordingProcess); 
                break;
        }
    } else {  
        printf("Error: MainHost failed to fork AVRecordingProcess\n");
        error = -1;
    } 

    return error;

}

void stopAllRecordings() {
    int ret; 
    FILE *infile, *outfile;
    int ch;


    printf("Terminating child processes..%d\n", AVRecordingProcess);
    ret = killpg(AVRecordingProcess, SIGINT); <-- NEW
    printf("Sending interrupt to GStreamer process.. Status %d\n", ret);

    int status;
    printf("Wait for the GStreamer process %d to end....", AVRecordingProcess);
    waitpid(AVRecordingProcess,0,0); <-- NEW
    printf("GStreamer ended.\n"); 
}

它有效。

基本上，在创建AVRecordingProcess期间，我将其设置为进程组的头部。发送进程组SIGINT还将其发送到组内的其余进程。为了确保进程组结束，我使用了waitpid。

Linux专家，随时纠正我，谢谢！

无法终止分叉进程

2 个答案: