如何更改服务器以便多个客户端可以访问服务器中的共享数据？

Question

基本上，我在c中做了一个tcp项目，我做了这个，所以多个客户端可以使用fork连接到我的服务器。在我的服务器中，我有一个链表结构，用于保存客户端发送的数据。但是，当我将数据从客户端发送到位于服务器中的链接列表时，服务器会为该客户端创建新的链接列表。而不是将所有客户端数据添加到同一个链表。我肯定知道它不是链表的问题。 Fork（）复制了进程，因此在调用fork之后实际上有2个程序运行实例。所以是的，我意识到客户端没有与同一台服务器通信？我该如何解决这个问题？我摆脱了叉子吗？请从概念上向我解释我必须做些什么。我没有发布我的实际代码，因为它很敏感。但这基本上就是我在做的事情：

服务器：

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

void dostuff(int); /* function prototype */

void error(char *msg)
{
   perror(msg);
   exit(1);
}

int main(int argc, char *argv[])
{
  int sockfd, newsockfd, portno, clilen, pid;
  struct sockaddr_in serv_addr, cli_addr;

  if (argc < 2) {
     fprintf(stderr,"ERROR, no port provided\n");
     exit(1);
 }
 sockfd = socket(AF_INET, SOCK_STREAM, 0);
 if (sockfd < 0) 
    error("ERROR opening socket");
 bzero((char *) &serv_addr, sizeof(serv_addr));
 portno = atoi(argv[1]);
 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");
 listen(sockfd,5);
 clilen = sizeof(cli_addr);
 while (1) {
     newsockfd = accept(sockfd, 
           (struct sockaddr *) &cli_addr, &clilen);
     if (newsockfd < 0) 
         error("ERROR on accept");
     pid = fork();
     if (pid < 0)
         error("ERROR on fork");
     if (pid == 0)  {
         close(sockfd);
         dostuff(newsockfd);
         exit(0);
     }
     else close(newsockfd);
 } /* end of while */
 return 0; /* we never get here */
}


 void dostuff (int sock)
{
  int n;
  char buffer[256];

bzero(buffer,256);
n = read(sock,buffer,255);
if (n < 0) error("ERROR reading from socket");
printf("Here is the message: %s\n",buffer);
n = write(sock,"I got your message",18);
if (n < 0) error("ERROR writing to socket");

客户：

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> 

void error(char *msg)
{
    perror(msg);
    exit(0);
}

int main(int argc, char *argv[])
{
    int sockfd, portno, n;

    struct sockaddr_in serv_addr;
    struct hostent *server;

    char buffer[256];
    if (argc < 3) {
       fprintf(stderr,"usage %s hostname port\n", argv[0]);
       exit(0);
    }
    portno = atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr, 
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);
    serv_addr.sin_port = htons(portno);
    if (connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) < 0) 
        error("ERROR connecting");
    printf("Please enter the message: ");
    bzero(buffer,256);
    fgets(buffer,255,stdin);
    n = write(sockfd,buffer,strlen(buffer));
    if (n < 0) 
         error("ERROR writing to socket");
    bzero(buffer,256);
    n = read(sockfd,buffer,255);
    if (n < 0) 
         error("ERROR reading from socket");
    printf("%s\n",buffer);
    return 0;
}

Answer 1

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