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()
116 	if (tty->flow.stopped)  in pty_write()
120 		spin_lock_irqsave(&to->port->lock, flags);  in pty_write()
122 		c = tty_insert_flip_string(to->port, buf, c);  in pty_write()
123 		spin_unlock_irqrestore(&to->port->lock, flags);  in pty_write()
126 			tty_flip_buffer_push(to->port);  in pty_write()
132  *	pty_write_room	-	write space
141 	if (tty->flow.stopped)  in pty_write_room()
143 	return tty_buffer_space_avail(tty->link->port);  in pty_write_room()
152 		return -EFAULT;  in pty_set_lock()
154 		set_bit(TTY_PTY_LOCK, &tty->flags);  in pty_set_lock()
156 		clear_bit(TTY_PTY_LOCK, &tty->flags);  in pty_set_lock()
162 	int locked = test_bit(TTY_PTY_LOCK, &tty->flags);  in pty_get_lock()
173 		return -EFAULT;  in pty_set_pktmode()
175 	spin_lock_irq(&tty->ctrl.lock);  in pty_set_pktmode()
177 		if (!tty->ctrl.packet) {  in pty_set_pktmode()
178 			tty->link->ctrl.pktstatus = 0;  in pty_set_pktmode()
180 			tty->ctrl.packet = true;  in pty_set_pktmode()
183 		tty->ctrl.packet = false;  in pty_set_pktmode()
184 	spin_unlock_irq(&tty->ctrl.lock);  in pty_set_pktmode()
192 	int pktmode = tty->ctrl.packet;  in pty_get_pktmode()
203 		return -EINVAL;  in pty_signal()
205 	if (tty->link) {  in pty_signal()
206 		pgrp = tty_get_pgrp(tty->link);  in pty_signal()
216 	struct tty_struct *to = tty->link;  in pty_flush_buffer()
222 	if (to->ctrl.packet) {  in pty_flush_buffer()
223 		spin_lock_irq(&tty->ctrl.lock);  in pty_flush_buffer()
224 		tty->ctrl.pktstatus |= TIOCPKT_FLUSHWRITE;  in pty_flush_buffer()
225 		wake_up_interruptible(&to->read_wait);  in pty_flush_buffer()
226 		spin_unlock_irq(&tty->ctrl.lock);  in pty_flush_buffer()
232 	if (!tty || !tty->link)  in pty_open()
233 		return -ENODEV;  in pty_open()
235 	if (test_bit(TTY_OTHER_CLOSED, &tty->flags))  in pty_open()
237 	if (test_bit(TTY_PTY_LOCK, &tty->link->flags))  in pty_open()
239 	if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1)  in pty_open()
242 	clear_bit(TTY_IO_ERROR, &tty->flags);  in pty_open()
243 	clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);  in pty_open()
244 	set_bit(TTY_THROTTLED, &tty->flags);  in pty_open()
248 	set_bit(TTY_IO_ERROR, &tty->flags);  in pty_open()
249 	return -EIO;  in pty_open()
256 	if (tty->link && tty->link->ctrl.packet) {  in pty_set_termios()
257 		int extproc = (old_termios->c_lflag & EXTPROC) | L_EXTPROC(tty);  in pty_set_termios()
258 		int old_flow = ((old_termios->c_iflag & IXON) &&  in pty_set_termios()
259 				(old_termios->c_cc[VSTOP] == '\023') &&  in pty_set_termios()
260 				(old_termios->c_cc[VSTART] == '\021'));  in pty_set_termios()
265 			spin_lock_irq(&tty->ctrl.lock);  in pty_set_termios()
267 				tty->ctrl.pktstatus &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);  in pty_set_termios()
269 					tty->ctrl.pktstatus |= TIOCPKT_DOSTOP;  in pty_set_termios()
271 					tty->ctrl.pktstatus |= TIOCPKT_NOSTOP;  in pty_set_termios()
274 				tty->ctrl.pktstatus |= TIOCPKT_IOCTL;  in pty_set_termios()
275 			spin_unlock_irq(&tty->ctrl.lock);  in pty_set_termios()
276 			wake_up_interruptible(&tty->link->read_wait);  in pty_set_termios()
280 	tty->termios.c_cflag &= ~(CSIZE | PARENB);  in pty_set_termios()
281 	tty->termios.c_cflag |= (CS8 | CREAD);  in pty_set_termios()
285  *	pty_resize		-	resize event
296 	struct tty_struct *pty = tty->link;  in pty_resize()
298 	/* For a PTY we need to lock the tty side */  in pty_resize()
299 	mutex_lock(&tty->winsize_mutex);  in pty_resize()
300 	if (!memcmp(ws, &tty->winsize, sizeof(*ws)))  in pty_resize()
315 	tty->winsize = *ws;  in pty_resize()
316 	pty->winsize = *ws;	/* Never used so will go away soon */  in pty_resize()
318 	mutex_unlock(&tty->winsize_mutex);  in pty_resize()
323  *	pty_start - start() handler
324  *	pty_stop  - stop() handler
325  *	@tty: tty being flow-controlled
327  *	Propagates the TIOCPKT status to the master pty.
329  *	NB: only the master pty can be in packet mode so only the slave
336 	if (tty->link && tty->link->ctrl.packet) {  in pty_start()
337 		spin_lock_irqsave(&tty->ctrl.lock, flags);  in pty_start()
338 		tty->ctrl.pktstatus &= ~TIOCPKT_STOP;  in pty_start()
339 		tty->ctrl.pktstatus |= TIOCPKT_START;  in pty_start()
340 		spin_unlock_irqrestore(&tty->ctrl.lock, flags);  in pty_start()
341 		wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN);  in pty_start()
349 	if (tty->link && tty->link->ctrl.packet) {  in pty_stop()
350 		spin_lock_irqsave(&tty->ctrl.lock, flags);  in pty_stop()
351 		tty->ctrl.pktstatus &= ~TIOCPKT_START;  in pty_stop()
352 		tty->ctrl.pktstatus |= TIOCPKT_STOP;  in pty_stop()
353 		spin_unlock_irqrestore(&tty->ctrl.lock, flags);  in pty_stop()
354 		wake_up_interruptible_poll(&tty->link->read_wait, EPOLLIN);  in pty_stop()
359  *	pty_common_install		-	set up the pty pair
374 	int idx = tty->index;  in pty_common_install()
375 	int retval = -ENOMEM;  in pty_common_install()
377 	/* Opening the slave first has always returned -EIO */  in pty_common_install()
378 	if (driver->subtype != PTY_TYPE_MASTER)  in pty_common_install()
379 		return -EIO;  in pty_common_install()
385 	if (!try_module_get(driver->other->owner)) {  in pty_common_install()
389 	o_tty = alloc_tty_struct(driver->other, idx);  in pty_common_install()
394 	lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE);  in pty_common_install()
402 		driver->other->ttys[idx] = o_tty;  in pty_common_install()
403 		driver->ttys[idx] = tty;  in pty_common_install()
405 		memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));  in pty_common_install()
406 		tty->termios = driver->init_termios;  in pty_common_install()
407 		memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));  in pty_common_install()
408 		o_tty->termios = driver->other->init_termios;  in pty_common_install()
414 	tty_driver_kref_get(driver->other);  in pty_common_install()
416 	tty->link   = o_tty;  in pty_common_install()
417 	o_tty->link = tty;  in pty_common_install()
422 	o_tty->port = ports[0];  in pty_common_install()
423 	tty->port = ports[1];  in pty_common_install()
424 	o_tty->port->itty = o_tty;  in pty_common_install()
426 	tty_buffer_set_lock_subclass(o_tty->port);  in pty_common_install()
429 	tty->count++;  in pty_common_install()
430 	o_tty->count++;  in pty_common_install()
434 	module_put(driver->other->owner);  in pty_common_install()
443 	tty_port_put(tty->port);  in pty_cleanup()
456 	struct tty_struct *pair = tty->link;  in pty_remove()
458 	driver->ttys[tty->index] = NULL;  in pty_remove()
460 		pair->driver->ttys[pair->index] = NULL;  in pty_remove()
475 	case TIOCSIG:    /* Send signal to other side of pty */  in pty_bsd_ioctl()
478 		return -EINVAL;  in pty_bsd_ioctl()
480 	return -ENOIOCTLCMD;  in pty_bsd_ioctl()
488 	 * PTY ioctls don't require any special translation between 32-bit and  in pty_bsd_compat_ioctl()
489 	 * 64-bit userspace, they are already compatible.  in pty_bsd_compat_ioctl()
505  * The master side of a pty can do TIOCSPTLCK and thus
560 	pty_driver->driver_name = "pty_master";  in legacy_pty_init()
561 	pty_driver->name = "pty";  in legacy_pty_init()
562 	pty_driver->major = PTY_MASTER_MAJOR;  in legacy_pty_init()
563 	pty_driver->minor_start = 0;  in legacy_pty_init()
564 	pty_driver->type = TTY_DRIVER_TYPE_PTY;  in legacy_pty_init()
565 	pty_driver->subtype = PTY_TYPE_MASTER;  in legacy_pty_init()
566 	pty_driver->init_termios = tty_std_termios;  in legacy_pty_init()
567 	pty_driver->init_termios.c_iflag = 0;  in legacy_pty_init()
568 	pty_driver->init_termios.c_oflag = 0;  in legacy_pty_init()
569 	pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;  in legacy_pty_init()
570 	pty_driver->init_termios.c_lflag = 0;  in legacy_pty_init()
571 	pty_driver->init_termios.c_ispeed = 38400;  in legacy_pty_init()
572 	pty_driver->init_termios.c_ospeed = 38400;  in legacy_pty_init()
573 	pty_driver->other = pty_slave_driver;  in legacy_pty_init()
576 	pty_slave_driver->driver_name = "pty_slave";  in legacy_pty_init()
577 	pty_slave_driver->name = "ttyp";  in legacy_pty_init()
578 	pty_slave_driver->major = PTY_SLAVE_MAJOR;  in legacy_pty_init()
579 	pty_slave_driver->minor_start = 0;  in legacy_pty_init()
580 	pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;  in legacy_pty_init()
581 	pty_slave_driver->subtype = PTY_TYPE_SLAVE;  in legacy_pty_init()
582 	pty_slave_driver->init_termios = tty_std_termios;  in legacy_pty_init()
583 	pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;  in legacy_pty_init()
584 	pty_slave_driver->init_termios.c_ispeed = 38400;  in legacy_pty_init()
585 	pty_slave_driver->init_termios.c_ospeed = 38400;  in legacy_pty_init()
586 	pty_slave_driver->other = pty_driver;  in legacy_pty_init()
603  *	ptm_open_peer - open the peer of a pty
604  *	@master: the open struct file of the ptmx device node
605  *	@tty: the master of the pty being opened
609  *	(where they have the master fd and cannot access or trust the mount
612 int ptm_open_peer(struct file *master, struct tty_struct *tty, int flags)  in ptm_open_peer()  argument
616 	int retval = -EINVAL;  in ptm_open_peer()
619 	if (tty->driver != ptm_driver)  in ptm_open_peer()
620 		return -EIO;  in ptm_open_peer()
629 	path.mnt = devpts_mntget(master, tty->driver_data);  in ptm_open_peer()
634 	path.dentry = tty->link->driver_data;  in ptm_open_peer()
665 		return put_user(tty->index, (unsigned int __user *)arg);  in pty_unix98_ioctl()
666 	case TIOCSIG:    /* Send signal to other side of pty */  in pty_unix98_ioctl()
670 	return -ENOIOCTLCMD;  in pty_unix98_ioctl()
678 	 * PTY ioctls don't require any special translation between 32-bit and  in pty_unix98_compat_ioctl()
679 	 * 64-bit userspace, they are already compatible.  in pty_unix98_compat_ioctl()
689  *	ptm_unix98_lookup	-	find a pty master
694  *	Look up a pty master device. Called under the tty_mutex for now.
701 	/* Master must be open via /dev/ptmx */  in ptm_unix98_lookup()
702 	return ERR_PTR(-EIO);  in ptm_unix98_lookup()
706  *	pts_unix98_lookup	-	find a pty slave
711  *	Look up a pty master device. Called under the tty_mutex for now.
721 	tty = devpts_get_priv(file->f_path.dentry);  in pts_unix98_lookup()
723 	/* Master must be open before slave */  in pts_unix98_lookup()
725 		return ERR_PTR(-EIO);  in pts_unix98_lookup()
739 	if (tty->driver->subtype == PTY_TYPE_MASTER)  in pty_unix98_remove()
740 		fsi = tty->driver_data;  in pty_unix98_remove()
742 		fsi = tty->link->driver_data;  in pty_unix98_remove()
745 		devpts_kill_index(fsi, tty->index);  in pty_unix98_remove()
752 	seq_printf(m, "tty-index:\t%d\n", tty->index);  in pty_show_fdinfo()
789  *	ptmx_open		-	open a unix 98 pty master
793  *	Allocate a unix98 pty master device from the ptmx driver.
795  *	Locking: tty_mutex protects the init_dev work. tty->count should
811 	filp->f_mode |= FMODE_NONOTIFY;  in ptmx_open()
847 	set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */  in ptmx_open()
848 	tty->driver_data = fsi;  in ptmx_open()
852 	dentry = devpts_pty_new(fsi, index, tty->link);  in ptmx_open()
857 	tty->link->driver_data = dentry;  in ptmx_open()
859 	retval = ptm_driver->ops->open(tty, filp);  in ptmx_open()
863 	tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);  in ptmx_open()
869 	// This will also put-ref the fsi  in ptmx_open()
902 	ptm_driver->driver_name = "pty_master";  in unix98_pty_init()
903 	ptm_driver->name = "ptm";  in unix98_pty_init()
904 	ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;  in unix98_pty_init()
905 	ptm_driver->minor_start = 0;  in unix98_pty_init()
906 	ptm_driver->type = TTY_DRIVER_TYPE_PTY;  in unix98_pty_init()
907 	ptm_driver->subtype = PTY_TYPE_MASTER;  in unix98_pty_init()
908 	ptm_driver->init_termios = tty_std_termios;  in unix98_pty_init()
909 	ptm_driver->init_termios.c_iflag = 0;  in unix98_pty_init()
910 	ptm_driver->init_termios.c_oflag = 0;  in unix98_pty_init()
911 	ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;  in unix98_pty_init()
912 	ptm_driver->init_termios.c_lflag = 0;  in unix98_pty_init()
913 	ptm_driver->init_termios.c_ispeed = 38400;  in unix98_pty_init()
914 	ptm_driver->init_termios.c_ospeed = 38400;  in unix98_pty_init()
915 	ptm_driver->other = pts_driver;  in unix98_pty_init()
918 	pts_driver->driver_name = "pty_slave";  in unix98_pty_init()
919 	pts_driver->name = "pts";  in unix98_pty_init()
920 	pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;  in unix98_pty_init()
921 	pts_driver->minor_start = 0;  in unix98_pty_init()
922 	pts_driver->type = TTY_DRIVER_TYPE_PTY;  in unix98_pty_init()
923 	pts_driver->subtype = PTY_TYPE_SLAVE;  in unix98_pty_init()
924 	pts_driver->init_termios = tty_std_termios;  in unix98_pty_init()
925 	pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;  in unix98_pty_init()
926 	pts_driver->init_termios.c_ispeed = 38400;  in unix98_pty_init()
927 	pts_driver->init_termios.c_ospeed = 38400;  in unix98_pty_init()
928 	pts_driver->other = ptm_driver;  in unix98_pty_init()