#include <stdio.h>#include <stdarg.h>#include <stdlib.h>#include <string.h>#include <errno.h>#include <unistd.h>#include <getopt.h>#include <netdb.h>#include <pthread.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#define DICE_PORT 6173int do_debug = 0;int do_thread = 0;int do_stdin = 0;int do_sleep = 0;pthread_mutex_t count_mutex = PTHREAD_MUTEX_INITIALIZER;pthread_mutex_t rand_mutex = PTHREAD_MUTEX_INITIALIZER;int threadcount = 0;struct sockets {	int local;	FILE *in, *out;};struct sockets *get_sockets(int);int socket_setup(void);int debug(char *, ...);int fail(char *, ...);int warn(char *, ...);int roll_die(int);void *roll_dice(void *);void spawn(struct sockets *);intdebug(char *fmt, ...) {	va_list ap;	int r;	va_start(ap, fmt);	if (do_debug) {		r = vfprintf(stderr, fmt, ap);	} else {		r = 0;	}	va_end(ap);	return r;}intwarn(char *fmt, ...) {	int r;	va_list ap;	va_start(ap, fmt);	r = vfprintf(stderr, fmt, ap);	va_end(ap);	return r;}intfail(char *fmt, ...) {	int r;	va_list ap;	va_start(ap, fmt);	r = vfprintf(stderr, fmt, ap);	exit(1);	/* notreached */	va_end(ap);	return r;}introll_die(int n) {	int r;	pthread_mutex_lock(&rand_mutex);	r = rand() % n + 1;	pthread_mutex_unlock(&rand_mutex);	return r;}/* read dice on standard input, write results on standard output */void *roll_dice(void *v) {	struct sockets *s = v;	char inbuf[512];	/* think globally, program defensively */	if (!s || !s->out || !s->in)		return NULL;	fprintf(s->out, "enter die rolls, or q to quit\n");	while (fgets(inbuf, sizeof(inbuf), s->in) != 0) {		int dice;		int size;		if (inbuf[0] == 'q') {			fprintf(s->out, "buh-bye!\n");			if (s->local == 0) {				shutdown(fileno(s->out), SHUT_RDWR);			}			fclose(s->out);			fclose(s->in);			if (s->local == 0) {				free(s);			}			pthread_mutex_lock(&count_mutex);			--threadcount;			/* last one out closes the lights */			if (threadcount == 0)				exit(0);			pthread_mutex_unlock(&count_mutex);			return 0;		}		if (sscanf(inbuf, "%dd%d", &dice, &size) != 2) {			fprintf(s->out, "Sorry, but I couldn't understand that.\n");		} else {			int i;			int total = 0;			for (i = 0; i < dice; ++i) {				int x = roll_die(size);				total += x;				fprintf(s->out, "%d ", x);				fflush(s->out);				if (do_sleep)					sleep(1);			}			fprintf(s->out, "= %d\n", total);		}	}	return 0;}intmain(int argc, char *argv[]) {	int o;	int sock;	while ((o = getopt(argc, argv, "dstS")) != -1) {		switch (o) {		case 'S':			do_sleep = 1;			break;		case 'd':			do_debug = 1;			break;		case 's':			do_stdin = 1;			break;		case 't':			do_thread = 1;			break;		}	}	if (do_thread) {		/* set up mutexes */		pthread_mutex_init(&count_mutex, NULL);		pthread_mutex_init(&rand_mutex, NULL);	}	if (do_stdin) {		struct sockets s;		s.local = 1;		s.in = stdin;		s.out = stdout;		if (do_thread) {			spawn(&s);		} else {			roll_dice(&s);			exit(0);		}	}	sock = socket_setup();	while (1) {		struct sockets *s = get_sockets(sock);		if (s) {			if (do_thread) {				spawn(s);			} else {				roll_dice(s);				exit(0);			}		}	}	return 0;}intsocket_setup(void) {	struct protoent *tcp_proto;	struct sockaddr_in local;	int r, s, one;	tcp_proto = getprotobyname("tcp");	if (!tcp_proto) {		fail("Can't find TCP/IP protocol: %s\n", strerror(errno));	}	s = socket(PF_INET, SOCK_STREAM, tcp_proto->p_proto);	if (s == -1) {		fail("socket: %s\n", strerror(errno));	}	one = 1;	setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));	memset(&local, 0, sizeof(struct sockaddr_in));	local.sin_family = AF_INET;	local.sin_port = htons(DICE_PORT);	r = bind(s, (struct sockaddr *) &local, sizeof(struct sockaddr_in));	if (r == -1) {		fail("bind: %s\n", strerror(errno));	}	r = listen(s, 5);	if (r == -1) {		fail("listen: %s\n", strerror(errno));	}	return s;}struct sockets *get_sockets(int sock) {	int conn;	if ((conn = accept(sock, NULL, NULL)) < 0) {		warn("accept: %s\n", strerror(errno));		return 0;	} else {		struct sockets *s;		s = malloc(sizeof(struct sockets));		if (s == NULL) {			warn("malloc failed.\n");			return 0;		}		s->local = 0;		s->in = fdopen(conn, "r");		s->out = fdopen(conn, "w");		setlinebuf(s->in);		setlinebuf(s->out);		return s;	}}voidspawn(struct sockets *s) {	pthread_t p;	pthread_mutex_lock(&count_mutex);	pthread_create(&p, NULL, roll_dice, (void *) s);	++threadcount;	pthread_mutex_unlock(&count_mutex);}