tcpserver.c

linux环境下的运用C程序语言写的TCP远程控制程序

/**********************************************************\
*                                                         *\
*  program name:tcpserver.c                               *
*  Author:Liang gang & Hu Xiao-qin                        *\
*  Funtion:This program is just a demostrate program      *\
*          to tell students how to use socket to          *\
*          make a tcp communation.                        *\
*  Date: 03-06-2009                                       *\
*                                                         *\
***********************************************************/


#include<stdlib.h>
#include<stdio.h>
#include<sys/socket.h>
#include<netdb.h>
#include<string.h>
#include<unistd.h>
#include<netinet/in.h>
#include<arpa/inet.h>

#define PORT 8300

int main(int argc,char** argv)
{
	struct sockaddr_in server;
	struct sockaddr_in client;
	int len;
	int port;
	int listend;
	int connectd;
	int sendnum;
	int opt;
	int recvnum;
	char send_buf[2048];
	char recv_buf[2048];
	char cmd[2048];


	port= PORT;
	memset(send_buf,0,2048);
	memset(recv_buf,0,2048);
	
      opt = SO_REUSEADDR;
      

      if (-1==(listend=socket(AF_INET,SOCK_STREAM,0)))
      {
	 perror("create listen socket error\n");
	 exit(1);
      }
      setsockopt(listend,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));

      #ifdef DEBUG
	printf("the listen id is %d\n",listend);
      #endif

     memset(&server,0,sizeof(struct sockaddr_in));
     server.sin_family = AF_INET;
     server.sin_addr.s_addr = htonl(INADDR_ANY);
     server.sin_port = htons(port);

     if (-1==bind(listend,(struct sockaddr *)&server,sizeof(struct sockaddr)))
     {
	perror("bind error\n");
	exit(1);

     }

    if (-1==listen(listend,5))
    {
	perror("listen error\n");
	exit(1);
    }

    while (1)
    {
    

        if (-1==(connectd=accept(listend,(struct sockaddr*)&client,&len)))

    	{
		perror("create connect socket error\n");
		continue;
    	}

     while(1)  
	 { if (0>(recvnum = recv(connectd,recv_buf,sizeof(recv_buf),0)))
	   {
		perror("recv error\n");
		close(connectd);
		continue;
	}
	    recv_buf[recvnum]='\0';

		if (0==strcmp(recv_buf,"quit"))
        {
		perror("the client break the server process\n");
		close(connectd);
		break;
	}

        strcpy(cmd,"/bin/");
		strcat(cmd,recv_buf);
		execute(cmd,send_buf);

		if ('\0'==*send_buf)
		{
			memset(cmd,0,sizeof(cmd));
			strcpy(cmd,"/sbin/");
			strcat(cmd,recv_buf);
			execute(cmd,send_buf);
			
			if ('\0'==*send_buf)
			{	
				memset(cmd,0,sizeof(cmd));
				strcpy(cmd,"/usr/bin/");
				strcat(cmd,recv_buf);
				execute(cmd,send_buf);
			}
			
			if ('\0'==*send_buf)
			{	
				memset(cmd,0,sizeof(cmd));
				strcpy(cmd,"/usr/sbin/");
				strcat(cmd,recv_buf);
				execute(cmd,send_buf);
			}
		}
		if ('\0'==*send_buf)
			sprintf(send_buf,"command is not vaild,check it please\n");

		printf("the server message is:%s\n",send_buf);

printf ("the message from the client is: %s\n",recv_buf);


        sendnum = sizeof(send_buf);
        send(connectd,send_buf,sendnum,0);
	 }

   }


    close(listend);
    return 0;



}

int execute(char* command,char* buf)
{
	FILE * 	fp;
	int count;

	if (NULL==(fp = popen(command,"r")))
	{
		perror("creating pipe error\n");
		exit(1);

	}
	
	count = 0 ;

	while(((buf[count] = fgetc(fp))!=EOF)&&count<2047)
	count++;
	buf[count]='\0';

	pclose(fp);
	return count;
	

}