Question

我的程序捕获来自互联网的网络流量，以分析数据包的不确定性。我正在使用winPcap库。现在我希望程序运行2分钟＆amp;自动退出程序而无需手动关闭命令提示符控制台。你能为我提供这样做的代码吗？谢谢

代码如下：

int main()
{
    u_int i, res , inum ;
    u_char errbuf[PCAP_ERRBUF_SIZE] , buffer[100];
    u_char *pkt_data;
    time_t seconds;
    struct tm tbreak;
    pcap_if_t *alldevs, *d;
    pcap_t *fp;
    struct pcap_pkthdr *header;

    fopen_s(&logfile , "log.txt" , "w");

    if(logfile == NULL) 
    {
        printf("Unable to create file.");
    }

    /* The user didn't provide a packet source: Retrieve the local device list */
    if (pcap_findalldevs_ex(PCAP_SRC_IF_STRING, NULL, &alldevs, errbuf) == -1)
    {
        fprintf(stderr,"Error in pcap_findalldevs_ex: %s\n", errbuf);
        return -1;
    }

    i = 0;
    /* Print the list */
    for(d=alldevs; d; d=d->next)  
    {
        printf("%d. %s\n    ", ++i, d->name);

        if (d->description)
        {
            printf(" (%s)\n", d->description);
        }
        else
        {
            printf(" (No description available)\n");
        }
    }

    if (i==0)
    {
        fprintf(stderr,"No interfaces found! Exiting.\n");
        return -1;
    }

    printf("Enter the interface number you would like to sniff : ");
    scanf_s("%d" , &inum);


    /* Jump to the selected adapter */
    for (d=alldevs, i=0; i< inum-1 ;d=d->next, i++);

    /* Open the device */
    if ( (fp= pcap_open(d->name,
                        100 /*snaplen*/,
                        PCAP_OPENFLAG_PROMISCUOUS /*flags*/,
                        20 /*read timeout*/,
                        NULL /* remote authentication */,
                        errbuf)
                        ) == NULL)
    {
        fprintf(stderr,"\nError opening adapter\n");
        return -1;
    }

    //read packets in a loop :)
    while((res = pcap_next_ex( fp, &header, &pkt_data)) >= 0)
    {
        if(res == 0)
        {
            // Timeout elapsed
            continue;
        }
        seconds = header->ts.tv_sec;
        localtime_s( &tbreak , &seconds);
        strftime (buffer , 80 , "%d-%b-%Y %I:%M:%S %p" , &tbreak );
        //print pkt timestamp and pkt len
        //fprintf(logfile , "\nNext Packet : %ld:%ld (Packet Length : %ld bytes) " , header->ts.tv_sec, header->ts.tv_usec, header->len);
        fprintf(logfile , "\nNext Packet : %s.%ld (Packet Length : %ld bytes) " , buffer , header->ts.tv_usec, header->len);
        ProcessPacket(pkt_data , header->caplen);
    }

    if(res == -1)
    {
        fprintf(stderr, "Error reading the packets: %s\n" , pcap_geterr(fp) );
        return -1;
    }

    return 0;
}

Answer 1

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

void exitfunc(int sig)
{
    _exit();
}

int main(int argc, char **argv)
{
    signal(SIGALRM, exitfunc);
    alarm(120);

    return 0;
}

应该有效

如何在C中执行特定时间后退出main函数

1 个答案: