/*      @(#)wwiomux.c   8.1 (Berkeley) 6/6/93   */
/*      $NetBSD: wwiomux.c,v 1.14 2009/04/14 08:50:06 lukem Exp $       */

/*
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Edward Wang at The University of California, Berkeley.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#if !defined(OLD_TTY) && !defined(TIOCPKT_DATA)
#include <sys/ioctl.h>
#endif
#include <sys/time.h>
#include <poll.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <err.h>
#include "ww.h"

/*
 * Multiple window output handler.
 * The idea is to copy window outputs to the terminal, via the
 * display package.  We try to give wwcurwin highest priority.
 * The only return conditions are when there is keyboard input
 * and when a child process dies.
 * When there's nothing to do, we sleep in a select().
 * The history of this routine is interesting.
 */
void
wwiomux(void)
{
        struct ww *w;
        nfds_t nfd;
        int i;
        int volatile dostdin;   /* avoid longjmp clobbering */
        char volatile c;        /* avoid longjmp clobbering */
        char *p;
        int millis;
        char noblock = 0;
        static struct pollfd *pfd = NULL;
        static nfds_t maxfds = 0;

        c = 0;  /* XXXGCC -Wuninitialized */

        for (;;) {
                if (wwinterrupt()) {
                        wwclrintr();
                        return;
                }

                nfd = 0;
                for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
                        if (w->ww_pty < 0 || w->ww_obq >= w->ww_obe)
                                continue;
                        nfd++;
                }

                if (maxfds <= ++nfd) {  /* One more for the fd=0 case below */
                        struct pollfd *npfd = pfd == NULL ?
                            malloc(sizeof(*pfd) * nfd) :
                           realloc(pfd, sizeof(*pfd) * nfd);
                        if (npfd == NULL) {
                                warn("will retry");
                                if (pfd)
                                        free(pfd);
                                pfd = NULL;
                                maxfds = 0;
                                return;
                        }
                        pfd = npfd;
                        maxfds = nfd;
                }

                nfd = 0;
                for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
                        if (w->ww_pty < 0)
                                continue;
                        if (w->ww_obq < w->ww_obe) {
                                pfd[nfd].fd = w->ww_pty;
                                pfd[nfd++].events = POLLIN;
                        }
                        if (w->ww_obq > w->ww_obp &&
                            !ISSET(w->ww_pflags, WWP_STOPPED))
                                noblock = 1;
                }
                if (wwibq < wwibe) {
                        dostdin = nfd;
                        pfd[nfd].fd = 0;
                        pfd[nfd++].events = POLLIN;
                } else {
                        dostdin = -1;
                }

                if (!noblock) {
                        if (wwcurwin != 0)
                                wwcurtowin(wwcurwin);
                        wwupdate();
                        wwflush();
                        (void) setjmp(wwjmpbuf);
                        wwsetjmp = 1;
                        if (wwinterrupt()) {
                                wwsetjmp = 0;
                                wwclrintr();
                                return;
                        }
                        /* XXXX */
                        millis = 30000;
                } else {
                        millis = 10;
                }
                wwnselect++;
                i = poll(pfd, nfd, millis);
                wwsetjmp = 0;
                noblock = 0;

                if (i < 0)
                        wwnselecte++;
                else if (i == 0)
                        wwnselectz++;
                else {
                        if (dostdin != -1 && (pfd[dostdin].revents & POLLIN) != 0)
                                wwrint();

                        nfd = 0;
                        for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw) {
                                int n;

                                if (w->ww_pty < 0)
                                        continue;
                                if (w->ww_pty != pfd[nfd].fd)
                                        continue;
                                if ((pfd[nfd++].revents & POLLIN) == 0)
                                        continue;
                                wwnwread++;
                                p = w->ww_obq;
                                if (w->ww_type == WWT_PTY) {
                                        if (p == w->ww_ob) {
                                                w->ww_obp++;
                                                w->ww_obq++;
                                        } else
                                                p--;
                                        c = *p;
                                }
                                n = read(w->ww_pty, p, w->ww_obe - p);
                                if (n < 0) {
                                        wwnwreade++;
                                        (void) close(w->ww_pty);
                                        w->ww_pty = -1;
                                } else if (n == 0) {
                                        wwnwreadz++;
                                        (void) close(w->ww_pty);
                                        w->ww_pty = -1;
                                } else if (w->ww_type != WWT_PTY) {
                                        wwnwreadd++;
                                        wwnwreadc += n;
                                        w->ww_obq += n;
                                } else if (*p == TIOCPKT_DATA) {
                                        n--;
                                        wwnwreadd++;
                                        wwnwreadc += n;
                                        w->ww_obq += n;
                                } else {
                                        wwnwreadp++;
                                        if (*p & TIOCPKT_STOP)
                                                SET(w->ww_pflags, WWP_STOPPED);
                                        if (*p & TIOCPKT_START)
                                                CLR(w->ww_pflags, WWP_STOPPED);
                                        if (*p & TIOCPKT_FLUSHWRITE) {
                                                CLR(w->ww_pflags, WWP_STOPPED);
                                                w->ww_obq = w->ww_obp =
                                                        w->ww_ob;
                                        }
                                }
                                if (w->ww_type == WWT_PTY)
                                        *p = c;
                        }
                }
                /*
                 * Try the current window first, if there is output
                 * then process it and go back to the top to try again.
                 * This can lead to starvation of the other windows,
                 * but presumably that what we want.
                 * Update will eventually happen when output from wwcurwin
                 * dies down.
                 */
                if ((w = wwcurwin) != NULL && w->ww_pty >= 0 &&
                    w->ww_obq > w->ww_obp &&
                    !ISSET(w->ww_pflags, WWP_STOPPED)) {
                        int n = wwwrite(w, w->ww_obp, w->ww_obq - w->ww_obp);
                        if ((w->ww_obp += n) == w->ww_obq)
                                w->ww_obq = w->ww_obp = w->ww_ob;
                        noblock = 1;
                        continue;
                }
                for (w = wwhead.ww_forw; w != &wwhead; w = w->ww_forw)
                        if (w->ww_pty >= 0 && w->ww_obq > w->ww_obp &&
                            !ISSET(w->ww_pflags, WWP_STOPPED)) {
                                int n = wwwrite(w, w->ww_obp,
                                        w->ww_obq - w->ww_obp);
                                if ((w->ww_obp += n) == w->ww_obq)
                                        w->ww_obq = w->ww_obp = w->ww_ob;
                                if (wwinterrupt())
                                        break;
                        }
        }
}