/* ----------------------------------------------------------------------------------------------------------- 
파일명 : multi_server.c 
기 능 : echo와 daytime을 같이 제공하는 멀티서버 
컴파일 : cc -o multi_server multi_server.c -lsocket -lnsl	
실행예 : multi_server 3001 
--------------------------------------------------------------------------------------------------------------*/ 
#include <sys/types.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 
#include <sys/wait.h> 
#include <stdio.h> 
#include <time.h> 
#include <string.h> 
extern int errno; 

#define MAXLINE 1024 

int main(int argc, char *argv[]) { 
int echo_fd, daytime_fd, s;	/* 소켓번호 */ 
int echo_port, daytime_port;	/* 포트번호 */ 
int nfds, len; 
fd_set read_fds; 
struct sockaddr_in server_addr, client_addr;	/* 소켓주소 구조체 */ 

if(argc != 2) { 
printf("실행방법: %s포트번호\n", argv[0]); 
return -1; 
} 
echo_port = atoi(argv[1]); 

/* daytime 서비스 포트번호를 임의로 배정 */ 
daytime_port = echo_port + 1;	

/* echo 서비스를 위한 소켓 생성 */ 
echo_fd = socket(PF_INET, SOCK_STREAM, 0); 
bzero((char *)&server_addr, sizeof(server_addr)); 
server_addr.sin_family = AF_INET; 
server_addr.sin_addr.s_addr = htonl(INADDR_ANY); 
server_addr.sin_port = htons(echo_port);
bind(echo_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)); 
/* daytime 서비스를 위한 소켓 생성 */ 
daytime_fd = socket(PF_INET, SOCK_STREAM, 0); 
server_addr.sin_port = htons(daytime_port); 
bind(daytime_fd,(struct sockaddr *)&server_addr,sizeof(server_addr)); 

listen(echo_fd, 5); 
listen(daytime_fd, 5); 

/*----------------------------------------- select() 호출 ------------------------------------------*/ 
nfds = daytime_fd + 1; 
FD_ZERO(&read_fds); 

while(1) { 
FD_SET(echo_fd, &read_fds); 
FD_SET(daytime_fd, &read_fds); 
if(select(nfds, &read_fds, (fd_set *)0, (fd_set *)0, (struct timeval *)0) < 0) { 
printf("select error: %s\n", strerror(errno)); 
} 


/*---------------------------------------------------------------------------------------------------------- 
echo 클라이언트가 접속을 요구해 온 경우 
---------------------------------------------------------------------------------------------------------*/ 
if(FD_ISSET(echo_fd, &read_fds)) { 
len = sizeof(client_addr); 
bzero((char *)&client_addr, len); 
s = accept(echo_fd, (struct sockaddr *)&client_addr, &len); 
echo_process(s); 
close(s); 
} 

/*----------------------------------------------------------------------------------------------------------- daytime 클라이언트가 접속을 요구해 온 경우 
---------------------------------------------------------------------------------------------------------*/ 
if(FD_ISSET(daytime_fd, &read_fds)) { 
len = sizeof(client_addr); 
s = accept(daytime_fd, (struct sockaddr *)&client_addr, &len); 
daytime_process(s);
close(s); 
} 
} 
} 

/*---------------------------------------------------------------------------------------------------------------- 
echo 서비스 처리 함수 정의 
-----------------------------------------------------------------------------------------------------------------*/ 
int echo_process(int echo_fd) { 
int len; 
char buf[MAXLINE]; 
while((len = read(echo_fd, buf, sizeof(buf))) != 0) { 
if (len < 0) { 
printf("echo: read error - %s\n", strerror(errno)); 
return -1; 
} 

if(write(echo_fd, buf, len) < 0) { 
printf("echo: write error - %s\n", strerror(errno)); 
return -1; 
} 
} 
return 0; 
} 

/*---------------------------------------------------------------------------------------------------------------- 
daytime 서비스 처리 함수 
----------------------------------------------------------------------------------------------------------------*/ 
int daytime_process(int daytime_fd) { 
time_t now; 
char buf[MAXLINE]; 
time(&now); 
sprintf(buf, "%s\n", ctime(&now)); 
if(write(daytime_fd, buf, strlen(buf)) < 0) { 
printf("daytime: write error - %s\n", strerror(errno)); 
return -1; 
} 
return 0; 
}