1 // SPDX-License-Identifier: GPL-2.0
5  *  Added support for a Unix98-style ptmx device.
6  *    -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
49 	if (tty->driver->subtype == PTY_TYPE_MASTER)  in pty_close()
50 		WARN_ON(tty->count > 1);  in pty_close()
54 		if (tty->count > 2)  in pty_close()
57 	set_bit(TTY_IO_ERROR, &tty->flags);  in pty_close()
58 	wake_up_interruptible(&tty->read_wait);  in pty_close()
59 	wake_up_interruptible(&tty->write_wait);  in pty_close()
60 	spin_lock_irq(&tty->ctrl.lock);  in pty_close()
61 	tty->ctrl.packet = false;  in pty_close()
62 	spin_unlock_irq(&tty->ctrl.lock);  in pty_close()
63 	/* Review - krefs on tty_link ?? */  in pty_close()
64 	if (!tty->link)  in pty_close()
66 	set_bit(TTY_OTHER_CLOSED, &tty->link->flags);  in pty_close()
67 	wake_up_interruptible(&tty->link->read_wait);  in pty_close()
68 	wake_up_interruptible(&tty->link->write_wait);  in pty_close()
69 	if (tty->driver->subtype == PTY_TYPE_MASTER) {  in pty_close()
70 		set_bit(TTY_OTHER_CLOSED, &tty->flags);  in pty_close()
72 		if (tty->driver == ptm_driver) {  in pty_close()
74 			if (tty->link->driver_data)  in pty_close()
75 				devpts_pty_kill(tty->link->driver_data);  in pty_close()
79 		tty_vhangup(tty->link);  in pty_close()
95 	tty_wakeup(tty->link);  in pty_unthrottle()
96 	set_bit(TTY_THROTTLED, &tty->flags);  in pty_unthrottle()
100  *	pty_write		-	write to a pty
108  *	the other side of the pty/tty pair.
113 	struct tty_struct *to = tty->link;  in pty_write()
115 	if (tty->flow.stopped || !c)  in pty_write()
118 	return tty_insert_flip_string_and_push_buffer(to->port, buf, c);  in pty_write()
122  *	pty_write_room	-	write space
131 	if (tty->flow.stopped)  in pty_write_room()
133 	return tty_buffer_space_avail(tty->link->port);  in pty_write_room()
142 		return -EFAULT;  in pty_set_lock()
144 		set_bit(TTY_PTY_LOCK, &tty->flags);  in pty_set_lock()
146 		clear_bit(TTY_PTY_LOCK, &tty->flags);  in pty_set_lock()
152 	int locked = test_bit(TTY_PTY_LOCK, &tty->flags);  in pty_get_lock()
163 		return -EFAULT;  in pty_set_pktmode()
165 	spin_lock_irq(&tty->ctrl.lock);  in pty_set_pktmode()
167 		if (!tty->ctrl.packet) {  in pty_set_pktmode()
168 			tty->link->ctrl.pktstatus = 0;  in pty_set_pktmode()
170 			tty->ctrl.packet = true;  in pty_set_pktmode()
173 		tty->ctrl.packet = false;  in pty_set_pktmode()
174 	spin_unlock_irq(&tty->ctrl.lock);  in pty_set_pktmode()
182 	int pktmode = tty->ctrl.packet;  in pty_get_pktmode()
193 		return -EINVAL;  in pty_signal()
195 	if (tty->link) {  in pty_signal()
196 		pgrp = tty_get_pgrp(tty->link);  in pty_signal()
206 	struct tty_struct *to = tty->link;  in pty_flush_buffer()
212 	if (to->ctrl.packet) {  in pty_flush_buffer()
213 		spin_lock_irq(&tty->ctrl.lock);  in pty_flush_buffer()
214 		tty->ctrl.pktstatus |= TIOCPKT_FLUSHWRITE;  in pty_flush_buffer()
215 		wake_up_interruptible(&to->read_wait);  in pty_flush_buffer()
216 		spin_unlock_irq(&tty->ctrl.lock);  in pty_flush_buffer()
222 	if (!tty || !tty->link)  in pty_open()
223 		return -ENODEV;  in pty_open()
225 	if (test_bit(TTY_OTHER_CLOSED, &tty->flags))  in pty_open()
227 	if (test_bit(TTY_PTY_LOCK, &tty->link->flags))  in pty_open()
229 	if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1)  in pty_open()
232 	clear_bit(TTY_IO_ERROR, &tty->flags);  in pty_open()
233 	clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);  in pty_open()
234 	set_bit(TTY_THROTTLED, &tty->flags);  in pty_open()
238 	set_bit(TTY_IO_ERROR, &tty->flags);  in pty_open()
239 	return -EIO;  in pty_open()
246 	if (tty->link && tty->link->ctrl.packet) {  in pty_set_termios()
247 		int extproc = (old_termios->c_lflag & EXTPROC) | L_EXTPROC(tty);  in pty_set_termios()
248 		int old_flow = ((old_termios->c_iflag & IXON) &&  in pty_set_termios()
249 				(old_termios->c_cc[VSTOP] == '\023') &&  in pty_set_termios()
250 				(old_termios->c_cc[VSTART] == '\021'));  in pty_set_termios()
255 			spin_lock_irq(&tty->ctrl.lock);  in pty_set_termios()
257 				tty->ctrl.pktstatus &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);  in pty_set_termios()
259 					tty->ctrl.pktstatus |= TIOCPKT_DOSTOP;  in pty_set_termios()
261 					tty->ctrl.pktstatus |= TIOCPKT_NOSTOP;  in pty_set_termios()
264 				tty->ctrl.pktstatus |= TIOCPKT_IOCTL;  in pty_set_termios()
265 			spin_unlock_irq(&tty->ctrl.lock);  in pty_set_termios()
266 			wake_up_interruptible(&tty->link->read_wait);  in pty_set_termios()
270 	tty->termios.c_cflag &= ~(CSIZE | PARENB);  in pty_set_termios()
271 	tty->termios.c_cflag |= (CS8 | CREAD);  in pty_set_termios()
275  *	pty_resize		-	resize event
286 	struct tty_struct *pty = tty->link;  in pty_resize()
288 	/* For a PTY we need to lock the tty side */  in pty_resize()
289 	mutex_lock(&tty->winsize_mutex);  in pty_resize()
290 	if (!memcmp(ws, &tty->winsize, sizeof(*ws)))  in pty_resize()
305 	tty->winsize = *ws;  in pty_resize()
306 	pty->winsize = *ws;	/* Never used so will go away soon */  in pty_resize()
308 	mutex_unlock(&tty->winsize_mutex);  in pty_resize()
313  *	pty_start - start() handler
314  *	pty_stop  - stop() handler
315  *	@tty: tty being flow-controlled
317  *	Propagates the TIOCPKT status to the master pty.
319  *	NB: only the master pty can be in packet mode so only the slave
326 	if (tty->link && tty->link->ctrl.packet) {  in pty_start()
327 		spin_lock_irqsave(&tty->ctrl.lock, flags);  in pty_start()
328 		tty->ctrl.pktstatus &= ~TIOCPKT_STOP;  in pty_start()
329 		tty->ctrl.pktstatus |= TIOCPKT_START;  in pty_start()
330 		spin_unlock_irqrestore(&tty->ctrl.lock, flags);  in pty_start()
331 		wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN);  in pty_start()
339 	if (tty->link && tty->link->ctrl.packet) {  in pty_stop()
340 		spin_lock_irqsave(&tty->ctrl.lock, flags);  in pty_stop()
341 		tty->ctrl.pktstatus &= ~TIOCPKT_START;  in pty_stop()
342 		tty->ctrl.pktstatus |= TIOCPKT_STOP;  in pty_stop()
343 		spin_unlock_irqrestore(&tty->ctrl.lock, flags);  in pty_stop()
344 		wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN);  in pty_stop()
349  *	pty_common_install		-	set up the pty pair
364 	int idx = tty->index;  in pty_common_install()
365 	int retval = -ENOMEM;  in pty_common_install()
367 	/* Opening the slave first has always returned -EIO */  in pty_common_install()
368 	if (driver->subtype != PTY_TYPE_MASTER)  in pty_common_install()
369 		return -EIO;  in pty_common_install()
375 	if (!try_module_get(driver->other->owner)) {  in pty_common_install()
379 	o_tty = alloc_tty_struct(driver->other, idx);  in pty_common_install()
384 	lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE);  in pty_common_install()
392 		driver->other->ttys[idx] = o_tty;  in pty_common_install()
393 		driver->ttys[idx] = tty;  in pty_common_install()
395 		memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));  in pty_common_install()
396 		tty->termios = driver->init_termios;  in pty_common_install()
397 		memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));  in pty_common_install()
398 		o_tty->termios = driver->other->init_termios;  in pty_common_install()
404 	tty_driver_kref_get(driver->other);  in pty_common_install()
406 	tty->link   = o_tty;  in pty_common_install()
407 	o_tty->link = tty;  in pty_common_install()
412 	o_tty->port = ports[0];  in pty_common_install()
413 	tty->port = ports[1];  in pty_common_install()
414 	o_tty->port->itty = o_tty;  in pty_common_install()
416 	tty_buffer_set_lock_subclass(o_tty->port);  in pty_common_install()
419 	tty->count++;  in pty_common_install()
420 	o_tty->count++;  in pty_common_install()
424 	module_put(driver->other->owner);  in pty_common_install()
433 	tty_port_put(tty->port);  in pty_cleanup()
446 	struct tty_struct *pair = tty->link;  in pty_remove()
448 	driver->ttys[tty->index] = NULL;  in pty_remove()
450 		pair->driver->ttys[pair->index] = NULL;  in pty_remove()
465 	case TIOCSIG:    /* Send signal to other side of pty */  in pty_bsd_ioctl()
468 		return -EINVAL;  in pty_bsd_ioctl()
470 	return -ENOIOCTLCMD;  in pty_bsd_ioctl()
478 	 * PTY ioctls don't require any special translation between 32-bit and  in pty_bsd_compat_ioctl()
479 	 * 64-bit userspace, they are already compatible.  in pty_bsd_compat_ioctl()
495  * The master side of a pty can do TIOCSPTLCK and thus
550 	pty_driver->driver_name = "pty_master";  in legacy_pty_init()
551 	pty_driver->name = "pty";  in legacy_pty_init()
552 	pty_driver->major = PTY_MASTER_MAJOR;  in legacy_pty_init()
553 	pty_driver->minor_start = 0;  in legacy_pty_init()
554 	pty_driver->type = TTY_DRIVER_TYPE_PTY;  in legacy_pty_init()
555 	pty_driver->subtype = PTY_TYPE_MASTER;  in legacy_pty_init()
556 	pty_driver->init_termios = tty_std_termios;  in legacy_pty_init()
557 	pty_driver->init_termios.c_iflag = 0;  in legacy_pty_init()
558 	pty_driver->init_termios.c_oflag = 0;  in legacy_pty_init()
559 	pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;  in legacy_pty_init()
560 	pty_driver->init_termios.c_lflag = 0;  in legacy_pty_init()
561 	pty_driver->init_termios.c_ispeed = 38400;  in legacy_pty_init()
562 	pty_driver->init_termios.c_ospeed = 38400;  in legacy_pty_init()
563 	pty_driver->other = pty_slave_driver;  in legacy_pty_init()
566 	pty_slave_driver->driver_name = "pty_slave";  in legacy_pty_init()
567 	pty_slave_driver->name = "ttyp";  in legacy_pty_init()
568 	pty_slave_driver->major = PTY_SLAVE_MAJOR;  in legacy_pty_init()
569 	pty_slave_driver->minor_start = 0;  in legacy_pty_init()
570 	pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;  in legacy_pty_init()
571 	pty_slave_driver->subtype = PTY_TYPE_SLAVE;  in legacy_pty_init()
572 	pty_slave_driver->init_termios = tty_std_termios;  in legacy_pty_init()
573 	pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;  in legacy_pty_init()
574 	pty_slave_driver->init_termios.c_ispeed = 38400;  in legacy_pty_init()
575 	pty_slave_driver->init_termios.c_ospeed = 38400;  in legacy_pty_init()
576 	pty_slave_driver->other = pty_driver;  in legacy_pty_init()
593  *	ptm_open_peer - open the peer of a pty
594  *	@master: the open struct file of the ptmx device node
595  *	@tty: the master of the pty being opened
599  *	(where they have the master fd and cannot access or trust the mount
602 int ptm_open_peer(struct file *master, struct tty_struct *tty, int flags)  in ptm_open_peer()  argument
606 	int retval = -EINVAL;  in ptm_open_peer()
609 	if (tty->driver != ptm_driver)  in ptm_open_peer()
610 		return -EIO;  in ptm_open_peer()
619 	path.mnt = devpts_mntget(master, tty->driver_data);  in ptm_open_peer()
624 	path.dentry = tty->link->driver_data;  in ptm_open_peer()
655 		return put_user(tty->index, (unsigned int __user *)arg);  in pty_unix98_ioctl()
656 	case TIOCSIG:    /* Send signal to other side of pty */  in pty_unix98_ioctl()
660 	return -ENOIOCTLCMD;  in pty_unix98_ioctl()
668 	 * PTY ioctls don't require any special translation between 32-bit and  in pty_unix98_compat_ioctl()
669 	 * 64-bit userspace, they are already compatible.  in pty_unix98_compat_ioctl()
679  *	ptm_unix98_lookup	-	find a pty master
684  *	Look up a pty master device. Called under the tty_mutex for now.
691 	/* Master must be open via /dev/ptmx */  in ptm_unix98_lookup()
692 	return ERR_PTR(-EIO);  in ptm_unix98_lookup()
696  *	pts_unix98_lookup	-	find a pty slave
701  *	Look up a pty master device. Called under the tty_mutex for now.
711 	tty = devpts_get_priv(file->f_path.dentry);  in pts_unix98_lookup()
713 	/* Master must be open before slave */  in pts_unix98_lookup()
715 		return ERR_PTR(-EIO);  in pts_unix98_lookup()
729 	if (tty->driver->subtype == PTY_TYPE_MASTER)  in pty_unix98_remove()
730 		fsi = tty->driver_data;  in pty_unix98_remove()
732 		fsi = tty->link->driver_data;  in pty_unix98_remove()
735 		devpts_kill_index(fsi, tty->index);  in pty_unix98_remove()
742 	seq_printf(m, "tty-index:\t%d\n", tty->index);  in pty_show_fdinfo()
779  *	ptmx_open		-	open a unix 98 pty master
783  *	Allocate a unix98 pty master device from the ptmx driver.
785  *	Locking: tty_mutex protects the init_dev work. tty->count should
801 	filp->f_mode |= FMODE_NONOTIFY;  in ptmx_open()
837 	set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */  in ptmx_open()
838 	tty->driver_data = fsi;  in ptmx_open()
842 	dentry = devpts_pty_new(fsi, index, tty->link);  in ptmx_open()
847 	tty->link->driver_data = dentry;  in ptmx_open()
849 	retval = ptm_driver->ops->open(tty, filp);  in ptmx_open()
853 	tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);  in ptmx_open()
859 	// This will also put-ref the fsi  in ptmx_open()
892 	ptm_driver->driver_name = "pty_master";  in unix98_pty_init()
893 	ptm_driver->name = "ptm";  in unix98_pty_init()
894 	ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;  in unix98_pty_init()
895 	ptm_driver->minor_start = 0;  in unix98_pty_init()
896 	ptm_driver->type = TTY_DRIVER_TYPE_PTY;  in unix98_pty_init()
897 	ptm_driver->subtype = PTY_TYPE_MASTER;  in unix98_pty_init()
898 	ptm_driver->init_termios = tty_std_termios;  in unix98_pty_init()
899 	ptm_driver->init_termios.c_iflag = 0;  in unix98_pty_init()
900 	ptm_driver->init_termios.c_oflag = 0;  in unix98_pty_init()
901 	ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;  in unix98_pty_init()
902 	ptm_driver->init_termios.c_lflag = 0;  in unix98_pty_init()
903 	ptm_driver->init_termios.c_ispeed = 38400;  in unix98_pty_init()
904 	ptm_driver->init_termios.c_ospeed = 38400;  in unix98_pty_init()
905 	ptm_driver->other = pts_driver;  in unix98_pty_init()
908 	pts_driver->driver_name = "pty_slave";  in unix98_pty_init()
909 	pts_driver->name = "pts";  in unix98_pty_init()
910 	pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;  in unix98_pty_init()
911 	pts_driver->minor_start = 0;  in unix98_pty_init()
912 	pts_driver->type = TTY_DRIVER_TYPE_PTY;  in unix98_pty_init()
913 	pts_driver->subtype = PTY_TYPE_SLAVE;  in unix98_pty_init()
914 	pts_driver->init_termios = tty_std_termios;  in unix98_pty_init()
915 	pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;  in unix98_pty_init()
916 	pts_driver->init_termios.c_ispeed = 38400;  in unix98_pty_init()
917 	pts_driver->init_termios.c_ospeed = 38400;  in unix98_pty_init()
918 	pts_driver->other = ptm_driver;  in unix98_pty_init()