www.pudn.com > pthread_examples.rar > dthread2.c

#include 
#include 
#include 
#include 
#include 

#include 
#include 
#include 
#include 

#include 
#include 
#include 

#define DICE_PORT 6173

int do_debug = 0;
int do_thread = 0;
int do_stdin = 0;
int do_sleep = 0;

pthread_mutex_t count_mutex = PTHREAD_MUTEX_INITIALIZER;   /*此处静态初始化线程锁*/
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 *);

int
debug(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;
}

int
warn(char *fmt, ...) {
	int r;
	va_list ap;
	va_start(ap, fmt);
	r = vfprintf(stderr, fmt, ap);
	va_end(ap);
	return r;
}
int
fail(char *fmt, ...) {
	int r;
	va_list ap;
	va_start(ap, fmt);
	r = vfprintf(stderr, fmt, ap);
	exit(1);
	/* notreached */
	va_end(ap);
	return r;
}

/*投骰子,获取一个随机数*/
int roll_die(int n) {
	return rand() % n + 1;
}

/* read dice on standard input, write results on standard output */
/*在标准输入上读入骰子,将结果在标准输出上输出*/
void * roll_dice(void *v) {

	printf("roll_dice running!\n");
	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");

	/*程序在此不断地读取数据*/
	while (fgets(inbuf, sizeof(inbuf), s->in) != 0) {
		int dice;
		int size;

		/*对退出的处理*/
		if (inbuf[0] == 'q') 
		{  /*表示该线程退出*/
			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);   /*如果所有的用户都退出该程序,则退出程序*/
			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)  /*如果指定do_sleep,则没停顿一秒投一次骰子*/
					sleep(1);
			}
			fprintf(s->out, "= %d\n", total);
		}
	}
	return 0;
}

int main(int argc, char *argv[]) {
	int o;
	int sock;
	/*getopt读取参数结束时返回-1*/
	while ((o = getopt(argc, argv, "dstS")) != -1) {
		switch (o) {
		case 'S':
			do_sleep = 1;
			break;
		case 'd':
			do_debug = 1;
			break;
		case 's':  /*指定了s, 进入控制台程序运行方式*/
			do_stdin = 1;
			break;
		case 't':
			do_thread = 1;
			break;
		}
	}

	if (do_thread) {
		/*启动线程锁使线程运行*/
		/* set up mutex for thread counting */
		pthread_mutex_init(&count_mutex, NULL);
	}

	if (do_stdin) {
		struct sockets s;
		s.local = 1;
		s.in = stdin;    /*指向标准输入*/
		s.out = stdout;  /*指向标准输出*/
		if (do_thread) {
			spawn(&s);
		} 
		else 
		{
			roll_dice(&s);
			exit(0);
		}
	}

	sock = socket_setup();
	while (1) {
		/*获取监听socket,如果没有连接进来,accept会被阻塞,除非设置成非阻塞*/
		struct sockets *s = get_sockets(sock);  
		if (s) {
			if (do_thread) {
				spawn(s);
			} else {
				roll_dice(s);
				exit(0);
			}
		}
	}
	return 0;
}

/*该函数用于建立socket*/
int socket_setup(void) {
	struct protoent *tcp_proto;
	struct sockaddr_in local;
	int r, s, one;

	tcp_proto = getprotobyname("tcp"); /*依据协议名称来获取协议的其他资料*/
	if (!tcp_proto) {
		fail("Can't find TCP/IP protocol: %s\n", strerror(errno));
	}
	
	/*tcp_proto->p_proto为tcp对应的通信协议的编号*/
	s = socket(PF_INET, SOCK_STREAM, tcp_proto->p_proto);
	if (s == -1) {
		fail("socket: %s\n", strerror(errno));
	}
	
	/*设置socket选项的参数*/
	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);
	/*将socket与地址,端口绑定在一起*/
	r = bind(s, (struct sockaddr *) &local, sizeof(struct sockaddr_in));
	if (r == -1) {
		fail("bind: %s\n", strerror(errno));
	}
	/*在绑定的socket上实现监听*/
	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");  /*将s->in流关联到conn文件描述符上*/
		s->out = fdopen(conn, "w");
		setlinebuf(s->in);  /*将相应的流关联为行缓存方式*/
		setlinebuf(s->out);
		return s;
	}
}

/*spawn创建一个线程,并不断地执行线程回调函数*/
/*如果一个线程正在创建,另一个线程退出,会出现竞态*/
void spawn(struct sockets *s) {
	pthread_t p;
	pthread_mutex_lock(&count_mutex);
	pthread_create(&p, NULL, roll_dice, (void *) s);  
	printf("spawn running\n");
	++threadcount; /*用于线程创建计数*/
	pthread_mutex_unlock(&count_mutex);
}