server1.c

先用makefile编译,连接后,client发字符到server端并返回该字符串,遇到a,e,i,o,u则加*号,如*a,收到fin字符串则结束客户端及服务器端程序.实现echo功能

/*
**server.c--a stream socket server demo
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>

#define MYPORT 3490  //the port users will be connecting to 

#define BACKLOG 10   //how many pending connections queue will hold

void sigchld_handler(int s)
{
   while(wait(NULL)>0);
}

int main(void)
{
 int sockfd, new_fd; //listen on sock_fd, new connection on new_fd
 struct sockaddr_in my_addr;   //my address information
 struct sockaddr_in their_addr;//connector's address information
 int sin_size;
 struct sigaction sa;
 int yes=1;
 char *recvbuf;
 char *caddr;
 int numbytes;

 
 if((sockfd=socket(AF_INET, SOCK_STREAM, 0))==-1){
    perror("socket");
    exit(1);
 } 

printf("SOCK_FD=%d\n", sockfd);
if(setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int))==-1){
   perror("setsockopt");
   exit(1);
}


my_addr.sin_family=AF_INET;     //host byte order
my_addr.sin_port=htons(MYPORT); //short, network byte order
my_addr.sin_addr.s_addr=INADDR_ANY;//automatically fill with my IP
memset(&(my_addr.sin_zero), '\0', 8);//zero the rest of the struct

if(bind(sockfd,(struct sockaddr*)&my_addr, sizeof(struct sockaddr))==-1){
   perror("bind");
   exit(1);
}

if(listen(sockfd, BACKLOG)==-1){
  perror("listen");
  exit(1);
}

sa.sa_handler=sigchld_handler; //reap all dead processes
sigemptyset(&sa.sa_mask);
sa.sa_flags=SA_RESTART;
if(sigaction(SIGCHLD, &sa, NULL)==-1){
  perror("sigaction");
  exit(1);
}

while(1){ //main accept() loop
   sin_size=sizeof(struct sockaddr_in);
   if((new_fd=accept(sockfd,(struct sockaddr*)&their_addr, &sin_size))==-1){
      perror("accept");
      continue;
}
printf("server: got connection from %s\n",(char*)inet_ntoa(their_addr.sin_addr));
//if(!fork()){ //this is the child process
    close(sockfd); //child doesn't need the listener
    recvbuf=(char*)calloc(128,sizeof(char));
  for(;;){
       numbytes=recv(new_fd, recvbuf,128,0);
       if(numbytes<0){
             perror("recv");
             close(new_fd);
             exit(1);
        }
 
  else if(numbytes==0||strncmp(recvbuf,"fin",3)==0){
            printf("clinet(%s) has been disconnected\n",(char*)inet_ntoa(their_addr.sin_addr));
               close(new_fd);
               exit(0);
               break;
           }
           printf("Received from %s: %s\n", inet_ntoa(their_addr.sin_addr),recvbuf);
           
void replace_string(char * source_str,char * targ_str,char *val)
{
        char temp_sstr[513],result[513];
        char * p,*q;
        int len;
        len=0;
        q=p=NULL;
        memset(result,0,sizeof(result));
        memset(temp_sstr,0,sizeof(temp_sstr));
        strcpy(temp_sstr,source_str);
        p=q=temp_sstr;
        len=strlen(targ_str);
        while(q!=NULL)
        {
                if((q=strstr(p,targ_str))!=NULL)
                {
                        strncat(result,p,q-p);
                        strcat(result,val);
                        strcat(result,"\0");
                        q+=len;
                        p=q;
                }
                else strcat(result,p);
        }
        strcpy(source_str,result);
}

          replace_string(recvbuf, "a", "a*");
          replace_string(recvbuf, "i", "i*");
          replace_string(recvbuf, "o", "o*");
          replace_string(recvbuf, "u", "u*");
          replace_string(recvbuf, "e", "e*");

           if(send(new_fd, recvbuf, numbytes, 0)==-1){
           perror("send");
                 close(new_fd);
                 exit(1);
           }
        }
        close(new_fd);
        exit(0);
       // }
        close(new_fd); //parent doesn't need this
        }
        return 0;
}