#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>

int descr;
struct message m,k;

struct message{
	long mtype;
	pid_t pid;
	char mtext[100];
};

static void sigHandle(int signum);

void main(){
	if(signal(SIGINT, sigHandle) == SIG_ERR){
		perror("Can't handle a signal SIGINT.");
		exit(1);
	}
	if(signal(SIGUSR1, sigHandle) == SIG_ERR){
		perror("Can't handle a signal SIGUSR1.");
		exit(1);
	}
	m.mtype = 1;
	m.pid = getpid();
	k.mtype = 2;
	descr = msgget(100,IPC_CREAT|0666);
	printf("descriptor : %d\n", descr);
	printf("PID : %d\n", getpid());
	if(descr==-1){
		printf("msgget");
	}
	while(1){
		strcpy(m.mtext, "[msg1] : ");
		char buf[100];
		scanf("%s", buf);
		strcat(m.mtext, buf);
		int res1=msgsnd(descr,&m,sizeof(struct message),0);
		if(res1==-1){
			printf("msgsnd");
		}
		int res2;
		do{
			res2=msgrcv(descr,&k,sizeof(struct message),2,IPC_NOWAIT);
			if(res2!=-1){
				printf("%s\n",k.mtext);
			}
		}while(res2!=-1);
	}
}

static void sigHandle(int signum){
	if(signum == SIGUSR1){
		printf("Other pal has quited.\n");
		exit(0);
	}
	if(signum == SIGINT){
		printf("\nSIGINT has been received, terminated.\n");
		kill(k.pid, SIGUSR1);
		msgctl(descr, IPC_RMID, 0);
		exit(0);
	}
};