usr/src/lib/libcurses/tstp.c

/*
 * Copyright (c) 1981 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
static char sccsid[] = "@(#)tstp.c      8.1 (Berkeley) %G%";
#endif /* not lint */

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


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

        /* Get the current terminal state (which the user may have changed). */
        if (tcgetattr(STDIN_FILENO, &save))
                return;

        /*
         * Block every signal we can get our hands on.  This is because
         * applications have timers going off that want to repaint the
         * screen.
         */
        (void)sigfillset(&set);
        (void)sigprocmask(SIG_BLOCK, &set, &oset);

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

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

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

        /* Time passes ... */

        /* Reset the curses SIGTSTP signal handler. */
        __set_stophandler();

        /* save the new "default" terminal state */
        (void)tcgetattr(STDIN_FILENO, &__orig_termios);

        /* Reset the terminal state to the mode just before we stopped. */
        (void)tcsetattr(STDIN_FILENO, __tcaction, &save);

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

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

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

static void (*otstpfn)() = SIG_DFL;

/*
 * Set the TSTP handler.
 */
void
__set_stophandler()
{
        otstpfn = signal(SIGTSTP, __stop_signal_handler);
}

/*
 * Restore the TSTP handler.
 */
void
__restore_stophandler()
{
        (void)signal(SIGTSTP, otstpfn);
}