c-无法终止分叉进程

Question

我有一个进程必须使用Ctrl-C或SIGINT终止。在这种情况下，我无法在键盘上使用Ctrl-C，因此必须在C中使用kill命令。这段代码基本上读取GPIO输入，并启动和停止一个脚本record.sh，一个GStreamer命令行脚本。

我只想终止在startVideoRecording（）中创建的子进程。我需要随心所欲地开始、停止、开始、停止录音。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。它只是挂在"向GStreamer进程发送中断..状态0"

如何确保使用Ctrl-C等效程序终止视频录制过程？

谢谢。

这是代码：

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 threadn");
            }
            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 AVRecordingProcessn");
                error = -1;
            case 0:
                execl("record.sh", "0", NULL);
                //system("//root//record.sh");
                printf("Error: Fail to execute AVRecordingProcessn");
                error = -1;
            default:
               printf("Video Recording...process id %dn", AVRecordingProcess); 
                break;
        }
    } else {  
        printf("Error: MainHost failed to fork AVRecordingProcessn");
        error = -1;
    } 
    return error;
}

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

    printf("Terminating child processes..%dn", AVRecordingProcess);
    ret = kill(AVRecordingProcess, SIGINT);
    printf("Sending interrupt to GStreamer process.. Status %dn", ret);
    int status;
    printf("Wait for the GStreamer process %d to end....", AVRecordingProcess);
    wait(AVRecordingProcess);
    printf("GStreamer ended.n"); 
}

Answer 1

是否有可能启动多个子进程，并且只将SIGINT发送到您创建的最后一个子进程，而不是以前的子进程？键入"PS"并在启动此程序后点击回车键，查看您启动了多少进程。

Answer 2

我最终做到了：

int startVideoRecording() {
    int error;
    error = 0;
    if ((AVRecordingProcess = fork()) != -1) {
        switch (AVRecordingProcess) {
            case -1:
                printf("Error: Fail to create AVRecordingProcessn");
                error = -1;
            case 0:
                setpgid(AVRecordingProcess,0);  <-- NEW
                execl("record.sh", "0", NULL);
                //system("//root//record.sh");
                printf("Error: Fail to execute AVRecordingProcessn");
                error = -1;
            default:
               printf("Video Recording...process id %dn", AVRecordingProcess); 
                break;
        }
    } else {  
        printf("Error: MainHost failed to fork AVRecordingProcessn");
        error = -1;
    } 
    return error;
}
void stopAllRecordings() {
    int ret; 
    FILE *infile, *outfile;
    int ch;

    printf("Terminating child processes..%dn", AVRecordingProcess);
    ret = killpg(AVRecordingProcess, SIGINT); <-- NEW
    printf("Sending interrupt to GStreamer process.. Status %dn", ret);
    int status;
    printf("Wait for the GStreamer process %d to end....", AVRecordingProcess);
    waitpid(AVRecordingProcess,0,0); <-- NEW
    printf("GStreamer ended.n"); 
}

它是有效的。

基本上，在创建AVRecordingProcess的过程中，我将其设置为流程组的负责人。发送进程组SIGINT也会将其发送到该组中的其他进程。为了确保进程组结束，我使用了waitpid。

Linux专家，请随时纠正我的错误，谢谢！