/*
 * Copyright (c) 2026 Mark Johnston <markj@FreeBSD.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

/*
 * A regression test that exercises a bug where TIOCNOTTY would leave some
 * dangling pointers behind in the controlling terminal structure.
 */

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

#include <err.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int
main(void)
{
        int master, slave, status;
        pid_t child;

        master = posix_openpt(O_RDWR | O_NOCTTY);
        if (master < 0)
                err(1, "posix_openpt");
        if (grantpt(master) < 0)
                err(1, "grantpt");
        if (unlockpt(master) < 0)
                err(1, "unlockpt");

        child = fork();
        if (child < 0)
                err(1, "fork");
        if (child == 0) {
                if (setsid() < 0)
                        err(1, "setsid");
                slave = open(ptsname(master), O_RDWR | O_NOCTTY);
                if (slave < 0)
                        err(2, "open");
                if (ioctl(slave, TIOCSCTTY, 0) < 0)
                        err(3, "ioctl(TIOCSCTTY)");
                /* Detach ourselves from the controlling terminal. */
                if (ioctl(slave, TIOCNOTTY, 0) < 0)
                        err(4, "ioctl(TIOCNOTTY)");
                _exit(0);
        }

        if (waitpid(child, &status, 0) < 0)
                err(1, "waitpid");
        if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
                errx(1, "child exited with status %d", WEXITSTATUS(status));

        child = fork();
        if (child < 0)
                err(1, "fork");
        if (child == 0) {
                struct winsize winsz;

                if (setsid() < 0)
                        err(1, "setsid");
                slave = open(ptsname(master), O_RDWR | O_NOCTTY);
                if (slave < 0)
                        err(2, "open");
                /* Dereferences dangling t_pgrp pointer in the terminal. */
                memset(&winsz, 0xff, sizeof(winsz));
                if (ioctl(slave, TIOCSWINSZ, &winsz) < 0)
                        err(3, "ioctl(TIOCSWINSZ)");
                /* Dereferences dangling t_session pointer in the terminal. */
                if (ioctl(slave, TIOCSCTTY, 0) < 0)
                        err(4, "ioctl(TIOCSCTTY)");
                _exit(0);
        }

        if (waitpid(child, &status, 0) < 0)
                err(1, "waitpid");
        if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
                errx(1, "child exited with status %d", WEXITSTATUS(status));
}