web03.c

UNIX环境下多线程的网络编程例子

#include	"unpthread.h"
#include	<thread.h>		/* Solaris threads */

#define	MAXFILES	20
#define	SERV		"80"	/* port number or service name */

struct file {
  char	*f_name;			/* filename */
  char	*f_host;			/* hostname or IP address */
  int    f_fd;				/* descriptor */
  int	 f_flags;			/* F_xxx below */
  int	 f_tid;				/* thread ID */
} file[MAXFILES];
#define	F_CONNECTING	1	/* connect() in progress */
#define	F_READING		2	/* connect() complete; now reading */
#define	F_DONE			4	/* all done */
#define	F_JOINED		8	/* main has pthread_join'ed */

#define	GET_CMD		"GET %s HTTP/1.0\r\n\r\n"

int		nconn, nfiles, nlefttoconn, nlefttoread;

int				ndone;		/* number of terminated threads */
pthread_mutex_t	ndone_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t	ndone_cond = PTHREAD_COND_INITIALIZER;

void	*do_get_read(void *);
void	home_page(const char *, const char *);
void	write_get_cmd(struct file *);

int
main(int argc, char **argv)
{
	int			i, maxnconn;
	pthread_t	tid;
	struct file	*fptr;

	if (argc < 5)
		err_quit("usage: web <#conns> <IPaddr> <homepage> file1 ...");
	maxnconn = atoi(argv[1]);

	nfiles = min(argc - 4, MAXFILES);
	for (i = 0; i < nfiles; i++) {
		file[i].f_name = argv[i + 4];
		file[i].f_host = argv[2];
		file[i].f_flags = 0;
	}
	printf("nfiles = %d\n", nfiles);

	home_page(argv[2], argv[3]);

	nlefttoread = nlefttoconn = nfiles;
	nconn = 0;
/* include web2 */
	while (nlefttoread > 0) {
		while (nconn < maxnconn && nlefttoconn > 0) {
				/* 4find a file to read */
			for (i = 0 ; i < nfiles; i++)
				if (file[i].f_flags == 0)
					break;
			if (i == nfiles)
				err_quit("nlefttoconn = %d but nothing found", nlefttoconn);

			Pthread_create(&tid, NULL, &do_get_read, &file[i]);
			file[i].f_tid = tid;
			file[i].f_flags = F_CONNECTING;
			nconn++;
			nlefttoconn--;
		}

			/* 4Wait for one of the threads to terminate */
		Pthread_mutex_lock(&ndone_mutex);
		while (ndone == 0)
			Pthread_cond_wait(&ndone_cond, &ndone_mutex);

		for (i = 0; i < nfiles; i++) {
			if (file[i].f_flags & F_DONE) {
				Pthread_join(file[i].f_tid, (void **) &fptr);

				if (&file[i] != fptr)
					err_quit("file[i] != fptr");
				fptr->f_flags = F_JOINED;	/* clears F_DONE */
				ndone--;
				nconn--;
				nlefttoread--;
				printf("thread %d for %s done\n", fptr->f_tid, fptr->f_name);
			}
		}
		Pthread_mutex_unlock(&ndone_mutex);
	}

	exit(0);
}
/* end web2 */

void *
do_get_read(void *vptr)
{
	int					fd, n;
	char				line[MAXLINE];
	struct file			*fptr;

	fptr = (struct file *) vptr;

	fd = Tcp_connect(fptr->f_host, SERV);
	fptr->f_fd = fd;
	printf("do_get_read for %s, fd %d, thread %d\n",
			fptr->f_name, fd, fptr->f_tid);

	write_get_cmd(fptr);	/* write() the GET command */

		/* 4Read server's reply */
	for ( ; ; ) {
		if ( (n = Read(fd, line, MAXLINE)) == 0)
			break;		/* server closed connection */

		printf("read %d bytes from %s\n", n, fptr->f_name);
	}
	printf("end-of-file on %s\n", fptr->f_name);
	Close(fd);
	fptr->f_flags = F_DONE;		/* clears F_READING */

	Pthread_mutex_lock(&ndone_mutex);
	ndone++;
	Pthread_cond_signal(&ndone_cond);
	Pthread_mutex_unlock(&ndone_mutex);

	return(fptr);		/* terminate thread */
}

void
write_get_cmd(struct file *fptr)
{
	int		n;
	char	line[MAXLINE];

	n = snprintf(line, sizeof(line), GET_CMD, fptr->f_name);
	Writen(fptr->f_fd, line, n);
	printf("wrote %d bytes for %s\n", n, fptr->f_name);

	fptr->f_flags = F_READING;			/* clears F_CONNECTING */
}

void
home_page(const char *host, const char *fname)
{
	int		fd, n;
	char	line[MAXLINE];

	fd = Tcp_connect(host, SERV);	/* blocking connect() */

	n = snprintf(line, sizeof(line), GET_CMD, fname);
	Writen(fd, line, n);

	for ( ; ; ) {
		if ( (n = Read(fd, line, MAXLINE)) == 0)
			break;		/* server closed connection */

		printf("read %d bytes of home page\n", n);
		/* do whatever with data */
	}
	printf("end-of-file on home page\n");
	Close(fd);
}