#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<sys/types.h>
#include<signal.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#define MAXLINE 1024

int readline(int,char *,int);
char *escapechar = "exit\n";

int main(int argc,char *argv[]){
	char line[MAXLINE],sendline[MAXLINE],recvline[MAXLINE+1];
	char *haddr;
	int n,size,comp,port;
	pid_t pid;
	static int s;
	static struct sockaddr_in server_addr;
	
	if(argc<3){
		printf("Usang: talk_client server_ip_addr port_number");
		return -1;
	}
	else{
		haddr = argv[1];
		port = atoi(argv[2]);
	}
	
	if( (s=socket(PF_INET,SOCK_STREAM,0)) < 0 ){
		printf("Client: Can't open stream socket.\n");
		return -1;
	}
	bzero((char *)&server_addr,sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_addr.s_addr = inet_addr(haddr);
	server_addr.sin_port = htons(port);

	if( connect(s,(struct sockaddr *)&server_addr,sizeof(server_addr)) < 0 ){
		perror("\n========== Client : can't connect to server. ==========\n\n");
		return -1;
	}
	else{
		printf("\n========== Client : Server connected ==========\n\n");
	}

	if((pid=fork())>0){
		while(readline(0,sendline,MAXLINE) != 0){
			size=strlen(sendline);
			if(write(s,sendline,strlen(sendline)) != size){
				printf("Client: can't write to server.\n");
				return -1;
			}
			if(strncmp(sendline,escapechar,4) == 0){
				kill(pid,SIGQUIT);
				break;
			}
		}
	}
	else if(pid ==0){
		while(1){
			if((size=read(s,recvline,MAXLINE))>0){
				recvline[size] = '\0';
				
				if(strncmp(recvline,escapechar,4)==0){
					kill(getppid(),SIGQUIT);
					break;
				}				
				printf("Server : %s",recvline);
			}
		}
	}
	printf("========== Bye Bye ==========\n\n");
	close(s);
	return 0;
}

int readline(int fd,char *ptr,int maxlen){
	int n,rc;
	char c;
	for(n=1;n<maxlen;n++){
		if((rc=read(fd,&c,1))==1){
			*ptr++ = c;
			if( c=='\n') break;
		}
		else if(rc==0){
			if(n==1) return 0;
			else break;
		}
	}
	*ptr=0;
	return n;
}
ÿ