客户端断开连接后 C 套接字 TCP 服务器失败

Question

我正在从这里修改服务器代码 http://www.linuxhowtos.org/C_C++/socket.htm .我想在客户端断开连接时重置服务器，以便下次为客户端准备好。但是当我关闭客户端时，服务器关闭并且服务器日志中没有任何内容。因为我一次只想处理一个客户，所以我不需要 fork ，对吗？否则服务器工作正常并响应我从我用 C# 编写的客户端发送的消息。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>

FILE *fp;

double square(double x)
{
     return x*x;
}

void error(const char *msg)
{
     fprintf(fp, "%s", msg);
     fprintf(fp, "%s", "\n");
}

int main(int argc, char *argv[])
{
     fp = fopen("serverlog.txt", "a");

     int sockfd;
     int newsockfd;
     int portno = 43635;
     int clientIsConnected;

     socklen_t clilen;
     char buffer[256];

     struct sockaddr_in serv_addr, cli_addr;
     int n;

while (1)
{
     sockfd = socket(AF_INET, SOCK_STREAM, 0);

     if (sockfd < 0)
     { 
          error("ERROR opening socket");
          close(sockfd);
          return 0;
     }

     bzero((char *) &serv_addr, sizeof(serv_addr));

     serv_addr.sin_family = AF_INET;
     serv_addr.sin_addr.s_addr = INADDR_ANY;
     serv_addr.sin_port = htons(portno);

     if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) 
     {
          error("ERROR on binding");
          close(sockfd);
          return 0;
     }

     if (listen(sockfd,5) < 0)
     {
          error("ERROR on listen");
          close(sockfd);
          return 0;
     }

     clilen = sizeof(cli_addr);
     newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);

     if (newsockfd < 0) 
     {
          error("ERROR on accept");
          close(newsockfd);
          close(sockfd);
          return 0;
     }

     clientIsConnected = 1;

     while (clientIsConnected)
     {
          bzero(buffer, 256);
          n = read(newsockfd, buffer, 255);

          if (n < 0)
          {
               error("ERROR reading from socket");
               clientIsConnected = 0;
               break;
          }

          double x = atof(buffer);
          double squared = square(x); 
          char response[256];
          sprintf(response, "%f", squared);

          n = write(newsockfd, response, strlen(response));

          if (n < 0)
          { 
               error("ERROR writing to socket");
               clientIsConnected = 0;
               break;
          }
     }
}

     close(sockfd);
     return 0; 
}

Answer 1

可能是你的服务器因为收到SIGPIPE而停止。你可以使用

信号(SIGPIPE，SIG_IGN)；

为了让您的程序继续运行，您可以在应用程序代码中处理关闭的通信。