sigio.c

Linux网络编程教程适合初学者入门学习

/*sigio.c*/
#include	<sys/types.h>
#include	<sys/socket.h>
#include	<netinet/in.h>
#include	<signal.h>
#include	<unistd.h>

int	fdqueue[20];
int	qsize = 0;
int	qtail = 0;
int	lfd;
void	signal_handle();
int
main()
{
	struct sockaddr_in	addr;
	struct signaction	act;
	sigset_t		sus, nes, ols;
	fd_set			wds;
	int			maxfd = 0;
	int 			i;
	lfd = socket(AF_INET, SOCK_STREAM, 0);
	if (lfd < 0) {
		printf("socket error: %s\n", strerror(errno));
		exit(1);
	}
	i = 1;
	setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
	bzero(&addr, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_port = htons(8080);
	addr.sin_addr.s_addr = htonl(INADDR_ANY);
	if (bind(lfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
		printf("bind error: %s\n", strerror(errno));
		exit(1);
	}
	act.sa_handler = sigio_handler;
	act.sa_mask = 0;
	act.sa_flags = 0;
	sigaction(SIGIO, &act, NULL);
	fcntl(lfd, F_SETOWN, getpid());
	i = 1;
	ioctl(lfd, FIOASYNC, &i);
	for (i=0; i<20; i++)
		cfd_queue[i] = -1;
	listen(lfd, 5);
	FD_ZERO(&wds);
	sigemptyset(&sus);
	sigemptyset(&ols);
	sigemptyset(&nes);
	sigaddset(&nes, SIGIO);
	sigprocmask(SIG_BLOCK, &nes, &ols);
	for ( ; ; ) {
		for ( ; qsize == 0; )
			sigsuspend(&sus);
		sigprocmask(SIG_SETMASK, &ols, NULL);
		for (i=0; i<20; i++) {
			if (cfd_queue[i] != -1) {
				FD_SET(fdqueue[i], &wds);
			maxfd = maxfd > fdqueue[i]? maxfd:cfd_queue[i];
			}
		}
		select(maxfd+1, NULL, &wds, NULL, NULL);
		for (i=0; i<20; i++) {
			if (FD_ISSET(fdqueue[i], &wds)) {
				write(fdqueue[i], "OK!", 3);
				close(fdqueue[i]);
				sigprocmask(SIG_BLOCK, &nes, &ols);
				fdqueue[i] = -1;
				qsize--;
			}
		}
	}
}
void
signal_handle(int sig)
{
	int	err;
	int	i;
	i = sizeof(err);
	getsockopt(lfd, SOL_SOCKET, SO_ERROR, &err, &i);
	if (err) {
		printf("socket pending error: %s\n", seterror(err));
		return;
	}
	if (qsize == 20)
		return;
	for ( ; fdqueue[qtail] >= 0; )
		qtail = ++qtail % 20;
	fdqueue[qtail] = accept(lfd, NULL, NULL);
	if (fdqueue[qtail] < 0) {
		printf("accept error: %s\n", strerror(errno));
		return;
	}
	qsize++;
}