Now works between SUNs and VAXen

[unix-history] / usr / src / usr.bin / talk / io.c

#ifndef lint
static char sccsid[] = "@(#)io.c	1.2 (Berkeley) %G%";
#endif

/*
 * This file contains the I/O handling and the exchange of 
 * edit characters. This connection itself is established in
 * ctl.c
 */

#include "talk.h"
#include <stdio.h>
#include <errno.h>
#include <sys/time.h>

#define A_LONG_TIME 10000000
#define STDIN_MASK (1<<fileno(stdin))	/* the bit mask for standard
					   input */
extern int errno;

/*
 * The routine to do the actual talking
 */
talk()
{
	register int read_template, sockt_mask;
	int read_set, nb;
	char buf[BUFSIZ];
	struct timeval wait;

	message("Connection established\007\007\007");
	current_line = 0;
	sockt_mask = (1<<sockt);

	/*
	 * Wait on both the other process (sockt_mask) and 
	 * standard input ( STDIN_MASK )
	 */
	read_template = sockt_mask | STDIN_MASK;
	forever {
		read_set = read_template;
		wait.tv_sec = A_LONG_TIME;
		wait.tv_usec = 0;
		nb = select(32, &read_set, 0, 0, &wait);
		if (nb <= 0) {
			if (errno == EINTR) {
				read_set = read_template;
				continue;
			}
			/* panic, we don't know what happened */
			p_error("Unexpected error from select");
			quit();
		}
		if (read_set & sockt_mask) { 
			/* There is data on sockt */
			nb = read(sockt, buf, sizeof buf);
			if (nb <= 0) {
				message("Connection closed. Exiting");
				quit();
			}
			display(&his_win, buf, nb);
		}
		if (read_set & STDIN_MASK) {
			/*
			 * We can't make the tty non_blocking, because
			 * curses's output routines would screw up
			 */
			ioctl(0, FIONREAD, (struct sgttyb *) &nb);
			nb = read(0, buf, nb);
			display(&my_win, buf, nb);
			/* might lose data here because sockt is non-blocking */
			write(sockt, buf, nb);
		}
	}
}

extern	int errno;
extern	int sys_nerr;
extern	char *sys_errlist[];

/*
 * p_error prints the system error message on the standard location
 * on the screen and then exits. (i.e. a curses version of perror)
 */
p_error(string) 
	char *string;
{
	char *sys;

	sys = "Unknown error";
	if (errno < sys_nerr)
		sys = sys_errlist[errno];
	wmove(my_win.x_win, current_line%my_win.x_nlines, 0);
	wprintw(my_win.x_win, "[%s : %s (%d)]\n", string, sys, errno);
	wrefresh(my_win.x_win);
	move(LINES-1, 0);
	refresh();
	quit();
}

/*
 * Display string in the standard location
 */
message(string)
	char *string;
{

	wmove(my_win.x_win, current_line%my_win.x_nlines, 0);
	wprintw(my_win.x_win, "[%s]\n", string);
	wrefresh(my_win.x_win);
}