client.c

linux平台下的网络通讯程序

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

#define SERVER_PORT 8888
#define MAX_BUF_SIZE 1024
#define MIN_BUF_SIZE 256
#define MSGLEN (sizeof(MSG))
#define SOCKLEN (sizeof(struct sockaddr_in))
void exit();
void bzero();
size_t strlen(const char *);
char *strcpy(char *,const char *);
typedef struct
{
    int ctl;
    char uinfo1[MIN_BUF_SIZE];
    char uinfo2[MIN_BUF_SIZE];
    char msg[MAX_BUF_SIZE];
}MSG;
void stopChild(pid_t child)
{
	if(kill(child,SIGSTOP)==-1)
	{
		printf("STOP Child Error:%s\n",strerror(errno));
		exit(1);
	}
}

void contChild(pid_t child)
{
	if(kill(child,SIGCONT)==-1)
	{
		printf("CONTUINE Child Error:%s\n",strerror(errno));
		exit(1);
	}
}

void trimStr(char *p)
{
	int len;
	len=(strlen(p));
	p[len-1]=0;
}
void send_msg(int sockfd,const MSG *buf,const struct sockaddr_in *addr)
{
    sendto(sockfd,(char *)buf,MSGLEN,0,(struct sockaddr *)addr,sizeof(struct sockaddr_in));
}
int recv_msg(int sockfd,MSG *p)
{
    int n;
    n=recvfrom(sockfd,p,MSGLEN,0,NULL,NULL);
    return n;
}
int main(int argc,char **argv)
{
    int sockfd;
    struct sockaddr_in addr,chataddr;
    if(argc!=2)
    {
    	fprintf(stderr,"Usage:%s server_ip\n",argv[0]);
    	exit(1);
    }
	sockfd=socket(AF_INET,SOCK_DGRAM,0);
    if(sockfd<0)
    {
    	fprintf(stderr,"Socket Error:%s\n",strerror(errno));
    	exit(1);
    }
    bzero(&addr,sizeof(struct sockaddr_in));
    addr.sin_family=AF_INET;
    addr.sin_port=htons(SERVER_PORT);
    if(inet_aton(argv[1],&addr.sin_addr)<0)
    {
			fprintf(stderr,"Ip error:%s\n",strerror(errno));
			exit(1);
    }
    pid_t child;
    if((child=fork())==-1)
    {
    	printf("Fork Error :%s\n",strerror(errno));
    	exit(1);
    }
    else if(child==0)
    {
			MSG current;
    	//子进程无限接收信息
    	while(1)
    	{
				printf("\n");
	    	recv_msg(sockfd,&current);
				printf("[%s]send to [%s] :%s",current.uinfo1,current.uinfo2,current.msg);
				bzero(&current,sizeof(MSG));
    	}
    }
    char ctl_str[MAX_BUF_SIZE];
    char my_uid[MAX_BUF_SIZE]="guest";
    int logstatus=0;
    MSG current;
    strcpy(current.uinfo1,"guest");
    printf("Your status is no login!\nType /help to see list.\n");	
    do
    {
    	//输入控制命令
    	fgets(ctl_str,MAX_BUF_SIZE,stdin);
			trimStr(ctl_str);
			if(strcmp(ctl_str,"/reg")==0){current.ctl=1;}
			else if(strcmp(ctl_str,"/login")==0){current.ctl=2;}
			else if(strcmp(ctl_str,"/logout")==0){current.ctl=3;}
			else if(strcmp(ctl_str,"/msg")==0){current.ctl=4;}
			else if(strcmp(ctl_str,"/listuser")==0){current.ctl=5;}
			else if(strcmp(ctl_str,"/help")==0){current.ctl=6;}
			else if(strcmp(ctl_str,"/exit")==0){current.ctl=7;}
			else current.ctl=0;
			switch(current.ctl)
			{
	    	case 1:{
						char temp[MAX_BUF_SIZE];
						printf("please input your uid :");
						fgets(current.uinfo1,MIN_BUF_SIZE,stdin);
						trimStr(current.uinfo1);
						printf("please input your pwd :");
						fgets(current.uinfo2,MIN_BUF_SIZE,stdin);
						trimStr(current.uinfo2);
						send_msg(sockfd,&current,&addr);
						//bzero(&current,MSGLEN);
						stopChild(child);
						recv_msg(sockfd,&current);
						contChild(child);
						int n;
						if((n=strcmp(current.msg,"registered"))==0)
						{
							printf("registere succeddful!\n");
						}else
						{ 
							printf("uid = %s,msg = %s \n",current.uinfo1,current.msg);
							printf("[#]unavail user! please try again by using other name.\n");
						}
					}break;
				case 2:{
					   if(logstatus == 1)
					   {
							printf("You have logined,please logout first.\n");
					   }
						else
						{
							char temp[MAX_BUF_SIZE];
							printf("please input your uid :");
							fgets(current.uinfo1,MIN_BUF_SIZE,stdin);
							trimStr(current.uinfo1);
							printf("please input your pwd :");
							fgets(current.uinfo2,MIN_BUF_SIZE,stdin);
							trimStr(current.uinfo2);
							send_msg(sockfd,&current,&addr);
							stopChild(child);
							recv_msg(sockfd,&current);
							contChild(child);
							//printf("msg = %s \n",current.msg);
							if(strcmp(current.msg,"login")==0)
							{
								strcpy(my_uid,current.uinfo1);
								logstatus = 1;
								printf("login succeddful!\n");
							}else
							{
								if(strcmp(current.msg,"user have login")==0)
								{
									printf("[#]the ID has login!please try the other ID plz.\n");
								}else
								printf("[#]unavail user! please confirm your user infomation and try again.\n");
							}
						}
				   }break;
				case 3:{
					   if(logstatus == 0)
					   {
						   printf("You haven't logined,please login first.\n");
					   }
					   else
					   {
						   int n;
						   strcpy(current.uinfo1,my_uid);
						   send_msg(sockfd,&current,&addr);
						   bzero(current.msg,MAX_BUF_SIZE);
						   stopChild(child);
						   recv_msg(sockfd,&current);
						   contChild(child);
						   if((n=strcmp(current.msg,"logout"))==0)
						   {
							   strcpy(my_uid,"guest");
							   logstatus = 0;
							   printf("logout succeddful!\n");
						   }else
						   {
							   printf("Something unexpect wrong happend,please try again.\n");
						   };		       
					   }
				   }break;
				case 4:{
					   if(logstatus==0)
					   {
						   printf("You haven't logined,please login first.\n");
					   }else
					   {
						   strcpy(current.uinfo1,my_uid);
						   printf("sendto :");
						   fgets(current.uinfo2,MIN_BUF_SIZE,stdin);
						   trimStr(current.uinfo2);
						   printf("msg :");
						   fgets(current.msg,MAX_BUF_SIZE,stdin);
						   trimStr(current.msg);
						   send_msg(sockfd,&current,&addr);	
					   }
				   }break;
				case 5:{
					   if(logstatus==0)
					   {
						   printf("You haven't logined,please login first.\n");
					   }else
					   {
						   strcpy(current.uinfo1,my_uid);
						   trimStr(current.uinfo2);
						   send_msg(sockfd,&current,&addr);	
					   }
				   }break;
				case 6:{
					   printf("/reg\n/login\n/logout\n/msg (send to \"all\" to chat to all)\n/listuser\n/exit\n");
				   }break;
				case 7:{
					   if(logstatus == 1)
					   {
						   int n;
						   current.ctl=3;
						   strcpy(current.uinfo1,my_uid);
						   send_msg(sockfd,&current,&addr);
						   bzero(current.msg,MAX_BUF_SIZE);
						   stopChild(child);
						   recv_msg(sockfd,&current);
						   contChild(child);
						   if((n=strcmp(current.msg,"logout"))==0)
						   {
							   strcpy(my_uid,"guest");
							   logstatus = 0;
							   printf("logout succeddful!\n");
						   }else
						   {
							   printf("Something unexpect wrong happend,please try again.\n");
							   if(kill(child,SIGTERM)==-1)
							   {
								   printf("Kill Child Error:%s\n",strerror(errno));
								   exit(1);
							   }
						   };		       
					   }
					   if(kill(child,SIGTERM)==-1)
					   {
						   printf("Kill Child Error:%s\n",strerror(errno));
						   exit(1);
					   }
					   exit(0);
				   }break;
			default:break;
		}
		bzero(&current,MSGLEN);
	}while(1);
	close(sockfd);
}