基於socket通訊的c/s模式開發

一個簡單的模型。server發送命令給client，client接收命令並處理。

//client.c

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define SERVPORT 3333
#define MAXDATASIZE 100    /*每次最大資料轉送量 */

main(int argc, char *argv[])
{
    int sock_fd, recvbytes;
    char buf[MAXDATASIZE];
    struct hostent *host;
    struct sockaddr_in serv_addr;
    if(argc< 2) {
        fprintf(stderr,"Please enter the server's hostname!/n");
        exit(1);
    }
    if((host=gethostbyname(argv[1])) == NULL) {
        herror("gethostbyname出錯！");
        exit(1);
    }
    if((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket建立出錯！");
        exit(1);
    }
    serv_addr.sin_family=AF_INET;
    serv_addr.sin_port=htons(SERVPORT);
    serv_addr.sin_addr = *((struct in_addr *)host->h_addr);
    bzero(&(serv_addr.sin_zero),8);
    if(connect(sock_fd, (struct sockaddr *)&serv_addr, sizeof(struct sockaddr)) == -1) {
        perror("connect出錯！");
        exit(1);
    }

    if((recvbytes=recv(sock_fd, buf, MAXDATASIZE, 0)) == -1) {
        perror("recv出錯！");
        exit(1);
    }
   
    buf[recvbytes] = '/0';
    printf("Received: %s/n",buf);
    if(!strcmp(buf, "ls"))
    {
      system("ls -l /");
    }
    if(!strcmp(buf, "date"));
    {
      system("date");
    }
  
    close(sock_fd);
}

 

//server.c

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#define SERVPORT 3333    /*伺服器監聽連接埠號碼 */
#define BACKLOG 10    /* 最大同時串連請求數 */

 

int main(int argc, char *argv[])
{
 
    if(argc<2)
      printf("enter command please/n");

   
    int sock_fd,client_fd;    /*sock_fd：監聽socket；client_fd：資料轉送socket */
    int sin_size;
    struct sockaddr_in my_addr;    /* 本機地址資訊 */
    struct sockaddr_in remote_addr;    /* 用戶端地址資訊 */
    if((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket error");
        exit(1);
    }
    my_addr.sin_family=AF_INET;
    my_addr.sin_port=htons(SERVPORT);
    my_addr.sin_addr.s_addr = INADDR_ANY;
    bzero(&(my_addr.sin_zero),8);
    if(bind(sock_fd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1) {
        perror("bind error");
        exit(1);
    }
    if(listen(sock_fd, BACKLOG) == -1) {
        perror("listen error");
        exit(1);
    }
    while(1) {
        sin_size = sizeof(struct sockaddr_in);
        if((client_fd = accept(sock_fd, (struct sockaddr *)&remote_addr, &sin_size)) == -1) {
            perror("accept error");
            continue;
        }
        printf("received a connection from %s/n", inet_ntoa(remote_addr.sin_addr));
        if(!fork()) { 
            if(send(client_fd, argv[1], 15, 0) == -1) {
                perror("send error");
            }
            close(client_fd);
            exit(0);
        }
        close(client_fd);
    }
}