/*      $OpenBSD: kqueue-pty.c,v 1.10 2019/03/04 19:35:28 anton Exp $   */

/*      Written by Michael Shalayeff, 2003, Public Domain       */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/event.h>

#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <util.h>

#include "main.h"

static int
pty_check(int kq, struct kevent *ev, int n, int rm, int rs, int wm, int ws)
{
        struct timespec ts;
        int i;

        ts.tv_sec = 0;
        ts.tv_nsec = 0;
        if ((n = kevent(kq, NULL, 0, ev, n, &ts)) < 0)
                err(1, "slave: kevent");

        ASSX(n != 0);

        for (i = 0; i < n; i++, ev++) {
                if (ev->filter == EVFILT_READ) {
                        ASSX(ev->ident != -rm);
                        ASSX(ev->ident != -rs);
                        if (ev->ident == rm)
                                rm = 0;
                        if (ev->ident == rs)
                                rs = 0;
                } else if (ev->filter == EVFILT_WRITE) {
                        ASSX(ev->ident != -wm);
                        ASSX(ev->ident != -ws);
                        if (ev->ident == wm)
                                wm = 0;
                        if (ev->ident == ws)
                                ws = 0;
                } else
                        errx(1, "unknown event");
        }
        ASSX(rm <= 0);
        ASSX(rs <= 0);
        ASSX(wm <= 0);
        ASSX(ws <= 0);

        return (0);
}

static int
pty_rdrw(void)
{
        struct kevent ev[4];
        struct termios tt;
        int fd, kq, massa, slave;
        char buf[1024];

        ASS((fd = open("/dev/console", O_RDONLY, &tt)) > 0,
            warn("open /dev/console"));
        ASS(tcgetattr(fd, &tt) == 0,
            warn("tcgetattr"));
        cfmakeraw(&tt);
        tt.c_lflag &= ~ECHO;
        if (openpty(&massa, &slave, NULL, &tt, NULL) < 0)
                err(1, "openpty");
        if (fcntl(massa, F_SETFL, O_NONBLOCK) < 0)
                err(1, "massa: fcntl");
        if (fcntl(slave, F_SETFL, O_NONBLOCK) < 0)
                err(1, "massa: fcntl");
        if ((kq = kqueue()) == -1)
                err(1, "kqueue");

        /* test the read from the slave works */
        EV_SET(&ev[0], massa, EVFILT_READ,  EV_ADD|EV_ENABLE, 0, 0, NULL);
        EV_SET(&ev[1], massa, EVFILT_WRITE, EV_ADD|EV_ENABLE, 0, 0, NULL);
        EV_SET(&ev[2], slave, EVFILT_READ,  EV_ADD|EV_ENABLE, 0, 0, NULL);
        EV_SET(&ev[3], slave, EVFILT_WRITE, EV_ADD|EV_ENABLE, 0, 0, NULL);
        if (kevent(kq, ev, 4, NULL, 0, NULL) < 0)
                err(1, "slave: kevent add");

        memset(buf, 0, sizeof(buf));

        ASSX(pty_check(kq, ev, 4, -massa, -slave, massa, slave) == 0);

        if (write(massa, " ", 1) != 1)
                err(1, "massa: write");

        ASSX(pty_check(kq, ev, 4, -massa, slave, massa, slave) == 0);

        read(slave, buf, sizeof(buf));

        ASSX(pty_check(kq, ev, 4, -massa, -slave, massa, slave) == 0);

        while (write(massa, buf, sizeof(buf)) > 0)
                continue;

        ASSX(pty_check(kq, ev, 4, -massa, slave, -massa, slave) == 0);

        read(slave, buf, 1);

        ASSX(pty_check(kq, ev, 4, -massa, slave, massa, slave) == 0);

        while (read(slave, buf, sizeof(buf)) > 0)
                continue;

        ASSX(pty_check(kq, ev, 4, -massa, -slave, massa, slave) == 0);

        return (0);
}

static int
pty_close(void)
{
        struct kevent ev[1];
        struct timespec ts;
        int kq, massa, n, slave;

        if (openpty(&massa, &slave, NULL, NULL, NULL) == -1)
                err(1, "openpty");

        kq = kqueue();
        if (kq == -1)
                err(1, "kqueue");

        EV_SET(&ev[0], massa, EVFILT_READ, EV_ADD|EV_ENABLE, 0, 0, NULL);
        if (kevent(kq, ev, 1, NULL, 0, NULL) == -1)
                err(1, "kevent: add");

        close(slave);

        ts.tv_sec = 5;
        ts.tv_nsec = 0;
        n = kevent(kq, NULL, 0, ev, 1, &ts);
        ASSX(n == 1);
        ASSX(ev[0].filter == EVFILT_READ);
        ASSX(ev[0].flags & EV_EOF);

        return 0;
}

int
do_pty(int n)
{
        switch (n) {
        case 1:
                return pty_rdrw();
        case 2:
                return pty_close();
        default:
                errx(1, "unknown pty test number %d", n);
        }
}