* Copyright (c) 1981, 1993, 1994

/* $NetBSD: tstp.c,v 1.45 2021/09/06 07:03:50 rin Exp $ */

/*
* Copyright (c) 1981, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* 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/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)tstp.c 8.3 (Berkeley) 5/4/94";
#else
__RCSID("$NetBSD: tstp.c,v 1.45 2021/09/06 07:03:50 rin Exp $");
#endif
#endif /* not lint */

#include <sys/ioctl.h>
#include <sys/param.h>

#include <errno.h>
#include <signal.h>
#include <termios.h>
#include <unistd.h>

#include "curses.h"
#include "curses_private.h"

static int tstp_set;
static int winch_set;

static void (*otstpfn)(int) = SIG_DFL;

static struct sigaction owsa;
#ifndef TCSASOFT
#define TCSASOFT 0
#endif

/*
* stop_signal_handler --
* Handle stop signals.
*/
void
__stop_signal_handler(/*ARGSUSED*/int signo)
{
sigset_t oset, set;

/*
* Block window change and timer signals. The latter is because
* applications use timers to decide when to repaint the screen.
*/
(void)sigemptyset(&set);
(void)sigaddset(&set, SIGALRM);
(void)sigaddset(&set, SIGWINCH);
(void)sigprocmask(SIG_BLOCK, &set, &oset);

/*
* End the window, which also resets the terminal state to the
* original modes.
*/
__stopwin();

/* Unblock SIGTSTP. */
(void)sigemptyset(&set);
(void)sigaddset(&set, SIGTSTP);
(void)sigprocmask(SIG_UNBLOCK, &set, NULL);

/* Stop ourselves. */
(void)kill(0, SIGTSTP);

/* Time passes ... */

/* restart things */
__restartwin();

/* Reset the signals. */
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
}

/*
* Set the TSTP handler.
*/
void
__set_stophandler(void)
{

__CTRACE(__CTRACE_MISC, "__set_stophandler: %d\n", tstp_set);
if (!tstp_set) {
otstpfn = signal(SIGTSTP, __stop_signal_handler);
tstp_set = 1;
}
}

/*
* Restore the TSTP handler.
*/
void
__restore_stophandler(void)
{

__CTRACE(__CTRACE_MISC, "__restore_stophandler: %d\n", tstp_set);
if (tstp_set) {
(void)signal(SIGTSTP, otstpfn);
tstp_set = 0;
}
}

/*
* winch_signal_handler --
* Handle winch signals by pushing KEY_RESIZE into the input stream.
*/
void
__winch_signal_handler(/*ARGSUSED*/int signo)
{
struct winsize win;

if (ioctl(fileno(_cursesi_screen->outfd), TIOCGWINSZ, &win) != -1 &&
win.ws_row != 0 && win.ws_col != 0)
{
LINES = win.ws_row;
COLS = win.ws_col;
}
/*
* If there was a previous handler, call that,
* otherwise tell getch() to send KEY_RESIZE.
*/
if (owsa.sa_handler != SIG_DFL &&
owsa.sa_handler != SIG_IGN &&
owsa.sa_handler != SIG_ERR &&
owsa.sa_handler != SIG_HOLD)
owsa.sa_handler(signo);
else
_cursesi_screen->resized = 1;
}

/*
* Set the WINCH handler.
*/
void
__set_winchhandler(void)
{

__CTRACE(__CTRACE_MISC, "__set_winchhandler: %d\n", winch_set);
if (!winch_set) {
struct sigaction sa;

sa.sa_handler = __winch_signal_handler;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
sigaction(SIGWINCH, &sa, &owsa);
winch_set = 1;
__CTRACE(__CTRACE_MISC,
"__set_winchhandler: owsa.sa_handler=%p\n",
owsa.sa_handler);
}
}

/*
* Restore the WINCH handler.
*/
void
__restore_winchhandler(void)
{

__CTRACE(__CTRACE_MISC, "__restore_winchhandler: %d\n", winch_set);
if (winch_set > 0) {
struct sigaction cwsa;

sigaction(SIGWINCH, NULL, &cwsa);
if (cwsa.sa_handler == owsa.sa_handler) {
sigaction(SIGWINCH, &owsa, NULL);
winch_set = 0;
} else {
/*
* We're now using the programs WINCH handler,
* so don't restore the previous one.
*/
winch_set = -1;
__CTRACE(__CTRACE_MISC, "cwsa.sa_handler = %p\n",
cwsa.sa_handler);
}
}
}

/* To allow both SIGTSTP and endwin() to come back nicely, we provide
the following routines. */

int
__stopwin(void)
{

__CTRACE(__CTRACE_MISC, "__stopwin\n");
if (_cursesi_screen == NULL)
return ERR;
if (_cursesi_screen->endwin)
return OK;

/* Get the current terminal state (which the user may have changed). */
(void)tcgetattr(fileno(_cursesi_screen->infd),
&_cursesi_screen->save_termios);

__restore_stophandler();
__restore_winchhandler();

if (curscr != NULL) {
__unsetattr(0);
__mvcur((int)curscr->cury, (int)curscr->curx,
(int)curscr->maxy - 1, 0, 0);
}

if (meta_on != NULL)
(void)tputs(meta_on, 0, __cputchar);

if ((curscr != NULL) && (curscr->flags & __KEYPAD))
(void)tputs(keypad_local, 0, __cputchar);
(void)tputs(cursor_normal, 0, __cputchar);
(void)tputs(exit_ca_mode, 0, __cputchar);
(void)fflush(_cursesi_screen->outfd);
#ifdef BSD
(void)setvbuf(_cursesi_screen->outfd, NULL, _IOLBF, 0);
#endif

_cursesi_screen->endwin = 1;

return tcsetattr(fileno(_cursesi_screen->infd), TCSASOFT | TCSADRAIN,
&_cursesi_screen->orig_termios) ? ERR : OK;
}

void
__restartwin(void)
{
struct winsize win;
int nlines, ncols;

__CTRACE(__CTRACE_MISC, "__restartwin\n");
if (!_cursesi_screen->endwin)
return;

/* Reset the curses SIGTSTP and SIGWINCH signal handlers. */
__set_stophandler();
__set_winchhandler();

/*
* Check to see if the window size has changed.
* If the application didn't update LINES and COLS,
* set the * resized flag to tell getch() to push KEY_RESIZE.
* Update curscr (which also updates __virtscr) and stdscr
* to match the new size.
*/
if (ioctl(fileno(_cursesi_screen->outfd), TIOCGWINSZ, &win) != -1 &&
win.ws_row != 0 && win.ws_col != 0)
{
if (win.ws_row != LINES) {
LINES = win.ws_row;
_cursesi_screen->resized = 1;
}
if (win.ws_col != COLS) {
COLS = win.ws_col;
_cursesi_screen->resized = 1;
}
}
/*
* We need to make local copies of LINES and COLS, otherwise we
* could lose if they are changed between wresize() calls.
*/
nlines = LINES;
ncols = COLS;
if (curscr->maxy != nlines || curscr->maxx != ncols)
wresize(curscr, nlines, ncols);
if (stdscr->maxy != nlines || stdscr->maxx != ncols)
wresize(stdscr, nlines, ncols);

/* save the new "default" terminal state */
(void)tcgetattr(fileno(_cursesi_screen->infd),
&_cursesi_screen->orig_termios);

/* Reset the terminal state to the mode just before we stopped. */
(void)tcsetattr(fileno(_cursesi_screen->infd), TCSASOFT | TCSADRAIN,
&_cursesi_screen->save_termios);

/* Restore colours */
__restore_colors();

/* Reset meta */
__restore_meta_state();

/* Restart the screen. */
__startwin(_cursesi_screen);

/* Reset cursor visibility */
__restore_cursor_vis();

/* Repaint the screen. */
wrefresh(curscr);
}

int
def_prog_mode(void)
{

if (_cursesi_screen->endwin)
return ERR;

return tcgetattr(fileno(_cursesi_screen->infd),
&_cursesi_screen->save_termios) ? ERR : OK;
}

int
reset_prog_mode(void)
{

return tcsetattr(fileno(_cursesi_screen->infd), TCSASOFT | TCSADRAIN,
&_cursesi_screen->save_termios) ? ERR : OK;
}

int
def_shell_mode(void)
{

return tcgetattr(fileno(_cursesi_screen->infd),
&_cursesi_screen->orig_termios) ? ERR : OK;
}

int
reset_shell_mode(void)
{

return __stopwin();
}