blob: b25d6c4014a54397448fc64fb215a5121c62a77b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/drivers/char/pty.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * Added support for a Unix98-style ptmx device.
7 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 *
Alan Coxfe9cd962008-10-13 10:43:38 +01009 * When reading this code see also fs/devpts. In particular note that the
10 * driver_data field is used by the devpts side as a binding to the devpts
11 * inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 */
13
Alan Coxfe9cd962008-10-13 10:43:38 +010014#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
16#include <linux/errno.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/interrupt.h>
18#include <linux/tty.h>
19#include <linux/tty_flip.h>
20#include <linux/fcntl.h>
Alexey Dobriyand43c36d2009-10-07 17:09:06 +040021#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/string.h>
23#include <linux/major.h>
24#include <linux/mm.h>
25#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/sysctl.h>
Alan Coxd81ed102008-10-13 10:41:42 +010027#include <linux/device.h>
Alan Coxfe9cd962008-10-13 10:43:38 +010028#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <linux/bitops.h>
30#include <linux/devpts_fs.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090031#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
Alan Coxfe9cd962008-10-13 10:43:38 +010033#include <asm/system.h>
34
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#ifdef CONFIG_UNIX98_PTYS
Roel Kluinda2bdf92009-01-07 18:09:15 -080036static struct tty_driver *ptm_driver;
Linus Torvalds1da177e2005-04-16 15:20:36 -070037static struct tty_driver *pts_driver;
38#endif
39
Alan Coxfe9cd962008-10-13 10:43:38 +010040static void pty_close(struct tty_struct *tty, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -070041{
Alan Coxfe9cd962008-10-13 10:43:38 +010042 BUG_ON(!tty);
43 if (tty->driver->subtype == PTY_TYPE_MASTER)
44 WARN_ON(tty->count > 1);
45 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 if (tty->count > 2)
47 return;
48 }
49 wake_up_interruptible(&tty->read_wait);
50 wake_up_interruptible(&tty->write_wait);
51 tty->packet = 0;
52 if (!tty->link)
53 return;
54 tty->link->packet = 0;
55 set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
56 wake_up_interruptible(&tty->link->read_wait);
57 wake_up_interruptible(&tty->link->write_wait);
58 if (tty->driver->subtype == PTY_TYPE_MASTER) {
59 set_bit(TTY_OTHER_CLOSED, &tty->flags);
60#ifdef CONFIG_UNIX98_PTYS
61 if (tty->driver == ptm_driver)
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +010062 devpts_pty_kill(tty->link);
Linus Torvalds1da177e2005-04-16 15:20:36 -070063#endif
Arnd Bergmann11dbf202010-06-18 14:58:07 +020064 tty_unlock();
65 tty_vhangup(tty->link);
66 tty_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 }
68}
69
70/*
71 * The unthrottle routine is called by the line discipline to signal
72 * that it can receive more characters. For PTY's, the TTY_THROTTLED
73 * flag is always set, to force the line discipline to always call the
Alan Coxfe9cd962008-10-13 10:43:38 +010074 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 * characters in the queue. This is necessary since each time this
76 * happens, we need to wake up any sleeping processes that could be
77 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
78 * for the pty buffer to be drained.
79 */
Alan Coxfe9cd962008-10-13 10:43:38 +010080static void pty_unthrottle(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -070081{
Alan Coxd945cb92009-07-07 16:39:41 +010082 tty_wakeup(tty->link);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 set_bit(TTY_THROTTLED, &tty->flags);
84}
85
Alan Coxd945cb92009-07-07 16:39:41 +010086/**
87 * pty_space - report space left for writing
88 * @to: tty we are writing into
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 *
Alan Coxd945cb92009-07-07 16:39:41 +010090 * The tty buffers allow 64K but we sneak a peak and clip at 8K this
91 * allows a lot of overspill room for echo and other fun messes to
92 * be handled properly
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 */
Alan Coxd945cb92009-07-07 16:39:41 +010094
95static int pty_space(struct tty_struct *to)
96{
97 int n = 8192 - to->buf.memory_used;
98 if (n < 0)
99 return 0;
100 return n;
101}
102
103/**
104 * pty_write - write to a pty
105 * @tty: the tty we write from
106 * @buf: kernel buffer of data
107 * @count: bytes to write
108 *
109 * Our "hardware" write method. Data is coming from the ldisc which
110 * may be in a non sleeping state. We simply throw this at the other
111 * end of the link as if we were an IRQ handler receiving stuff for
112 * the other side of the pty/tty pair.
113 */
114
Linus Torvaldsac89a912009-09-05 13:27:10 -0700115static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116{
117 struct tty_struct *to = tty->link;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
Alan Coxd945cb92009-07-07 16:39:41 +0100119 if (tty->stopped)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 return 0;
121
Alan Coxd945cb92009-07-07 16:39:41 +0100122 if (c > 0) {
123 /* Stuff the data into the input queue of the other end */
124 c = tty_insert_flip_string(to, buf, c);
125 /* And shovel */
Linus Torvalds202c4672009-09-18 07:05:58 -0700126 if (c) {
127 tty_flip_buffer_push(to);
128 tty_wakeup(tty);
129 }
Alan Cox762faae2009-06-16 17:01:13 +0100130 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 return c;
132}
133
Alan Coxd945cb92009-07-07 16:39:41 +0100134/**
135 * pty_write_room - write space
136 * @tty: tty we are writing from
137 *
138 * Report how many bytes the ldisc can send into the queue for
139 * the other device.
140 */
141
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142static int pty_write_room(struct tty_struct *tty)
143{
Linus Torvalds85dfd812009-08-10 13:21:19 -0700144 if (tty->stopped)
145 return 0;
Alan Coxd945cb92009-07-07 16:39:41 +0100146 return pty_space(tty->link);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147}
148
Alan Coxd945cb92009-07-07 16:39:41 +0100149/**
150 * pty_chars_in_buffer - characters currently in our tx queue
151 * @tty: our tty
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 *
Alan Coxd945cb92009-07-07 16:39:41 +0100153 * Report how much we have in the transmit queue. As everything is
154 * instantly at the other end this is easy to implement.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 */
Alan Coxd945cb92009-07-07 16:39:41 +0100156
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157static int pty_chars_in_buffer(struct tty_struct *tty)
158{
Alan Coxd945cb92009-07-07 16:39:41 +0100159 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160}
161
162/* Set the lock flag on a pty */
Alan Coxfe9cd962008-10-13 10:43:38 +0100163static int pty_set_lock(struct tty_struct *tty, int __user *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164{
165 int val;
Alan Coxfe9cd962008-10-13 10:43:38 +0100166 if (get_user(val, arg))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 return -EFAULT;
168 if (val)
169 set_bit(TTY_PTY_LOCK, &tty->flags);
170 else
171 clear_bit(TTY_PTY_LOCK, &tty->flags);
172 return 0;
173}
174
hyc@symas.com26df6d12010-06-22 10:14:49 -0700175/* Send a signal to the slave */
176static int pty_signal(struct tty_struct *tty, int sig)
177{
178 unsigned long flags;
179 struct pid *pgrp;
180
181 if (tty->link) {
182 spin_lock_irqsave(&tty->link->ctrl_lock, flags);
183 pgrp = get_pid(tty->link->pgrp);
184 spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
185
186 kill_pgrp(pgrp, sig, 1);
187 put_pid(pgrp);
188 }
189 return 0;
190}
191
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192static void pty_flush_buffer(struct tty_struct *tty)
193{
194 struct tty_struct *to = tty->link;
Alan Cox04f378b2008-04-30 00:53:29 -0700195 unsigned long flags;
Alan Coxfe9cd962008-10-13 10:43:38 +0100196
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 if (!to)
198 return;
Alan Coxd945cb92009-07-07 16:39:41 +0100199 /* tty_buffer_flush(to); FIXME */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 if (to->packet) {
Alan Cox04f378b2008-04-30 00:53:29 -0700201 spin_lock_irqsave(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
203 wake_up_interruptible(&to->read_wait);
Alan Cox04f378b2008-04-30 00:53:29 -0700204 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 }
206}
207
Alan Coxfe9cd962008-10-13 10:43:38 +0100208static int pty_open(struct tty_struct *tty, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209{
210 int retval = -ENODEV;
211
212 if (!tty || !tty->link)
213 goto out;
214
215 retval = -EIO;
216 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
217 goto out;
218 if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
219 goto out;
220 if (tty->link->count != 1)
221 goto out;
222
223 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
224 set_bit(TTY_THROTTLED, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 retval = 0;
226out:
227 return retval;
228}
229
Alan Coxfe9cd962008-10-13 10:43:38 +0100230static void pty_set_termios(struct tty_struct *tty,
231 struct ktermios *old_termios)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232{
Alan Coxfe9cd962008-10-13 10:43:38 +0100233 tty->termios->c_cflag &= ~(CSIZE | PARENB);
234 tty->termios->c_cflag |= (CS8 | CREAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235}
236
Alan Coxfc6f6232009-01-02 13:43:17 +0000237/**
238 * pty_do_resize - resize event
239 * @tty: tty being resized
Alan Coxc774bda2009-01-11 19:46:49 +0000240 * @ws: window size being set.
Alan Coxfc6f6232009-01-02 13:43:17 +0000241 *
Daniel Mack3ad2f3f2010-02-03 08:01:28 +0800242 * Update the termios variables and send the necessary signals to
Alan Coxfc6f6232009-01-02 13:43:17 +0000243 * peform a terminal resize correctly
244 */
245
246int pty_resize(struct tty_struct *tty, struct winsize *ws)
247{
248 struct pid *pgrp, *rpgrp;
249 unsigned long flags;
250 struct tty_struct *pty = tty->link;
251
252 /* For a PTY we need to lock the tty side */
253 mutex_lock(&tty->termios_mutex);
254 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
255 goto done;
256
257 /* Get the PID values and reference them so we can
258 avoid holding the tty ctrl lock while sending signals.
259 We need to lock these individually however. */
260
261 spin_lock_irqsave(&tty->ctrl_lock, flags);
262 pgrp = get_pid(tty->pgrp);
263 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
264
265 spin_lock_irqsave(&pty->ctrl_lock, flags);
266 rpgrp = get_pid(pty->pgrp);
267 spin_unlock_irqrestore(&pty->ctrl_lock, flags);
268
269 if (pgrp)
270 kill_pgrp(pgrp, SIGWINCH, 1);
271 if (rpgrp != pgrp && rpgrp)
272 kill_pgrp(rpgrp, SIGWINCH, 1);
273
274 put_pid(pgrp);
275 put_pid(rpgrp);
276
277 tty->winsize = *ws;
278 pty->winsize = *ws; /* Never used so will go away soon */
279done:
280 mutex_unlock(&tty->termios_mutex);
281 return 0;
282}
283
Linus Torvalds342a5972009-09-30 07:49:40 -0700284/* Traditional BSD devices */
285#ifdef CONFIG_LEGACY_PTYS
286
Alan Coxbf970ee2008-10-13 10:42:39 +0100287static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
288{
289 struct tty_struct *o_tty;
290 int idx = tty->index;
291 int retval;
292
293 o_tty = alloc_tty_struct();
294 if (!o_tty)
295 return -ENOMEM;
296 if (!try_module_get(driver->other->owner)) {
297 /* This cannot in fact currently happen */
Jiri Slaby8a1b8d72011-03-23 10:48:33 +0100298 retval = -ENOMEM;
299 goto err_free_tty;
Alan Coxbf970ee2008-10-13 10:42:39 +0100300 }
301 initialize_tty_struct(o_tty, driver->other, idx);
302
303 /* We always use new tty termios data so we can do this
304 the easy way .. */
305 retval = tty_init_termios(tty);
306 if (retval)
Jiri Slaby8a1b8d72011-03-23 10:48:33 +0100307 goto err_module_put;
Alan Coxbf970ee2008-10-13 10:42:39 +0100308
309 retval = tty_init_termios(o_tty);
Jiri Slaby8a1b8d72011-03-23 10:48:33 +0100310 if (retval)
311 goto err_free_termios;
Alan Coxfe9cd962008-10-13 10:43:38 +0100312
Alan Coxbf970ee2008-10-13 10:42:39 +0100313 /*
314 * Everything allocated ... set up the o_tty structure.
315 */
316 driver->other->ttys[idx] = o_tty;
317 tty_driver_kref_get(driver->other);
318 if (driver->subtype == PTY_TYPE_MASTER)
319 o_tty->count++;
320 /* Establish the links in both directions */
321 tty->link = o_tty;
322 o_tty->link = tty;
323
324 tty_driver_kref_get(driver);
325 tty->count++;
326 driver->ttys[idx] = tty;
327 return 0;
Jiri Slaby8a1b8d72011-03-23 10:48:33 +0100328err_free_termios:
329 tty_free_termios(tty);
330err_module_put:
Alan Coxbf970ee2008-10-13 10:42:39 +0100331 module_put(o_tty->driver->owner);
Jiri Slaby8a1b8d72011-03-23 10:48:33 +0100332err_free_tty:
Alan Coxbf970ee2008-10-13 10:42:39 +0100333 free_tty_struct(o_tty);
Jiri Slaby8a1b8d72011-03-23 10:48:33 +0100334 return retval;
Alan Coxbf970ee2008-10-13 10:42:39 +0100335}
336
Alan Cox6caa76b2011-02-14 16:27:22 +0000337static int pty_bsd_ioctl(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 unsigned int cmd, unsigned long arg)
339{
340 switch (cmd) {
341 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
342 return pty_set_lock(tty, (int __user *) arg);
hyc@symas.com26df6d12010-06-22 10:14:49 -0700343 case TIOCSIG: /* Send signal to other side of pty */
344 return pty_signal(tty, (int) arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 }
346 return -ENOIOCTLCMD;
347}
348
Kay Sieversdc8c8582007-08-15 12:25:38 +0200349static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
350module_param(legacy_count, int, 0);
351
Linus Torvalds342a5972009-09-30 07:49:40 -0700352/*
353 * The master side of a pty can do TIOCSPTLCK and thus
354 * has pty_bsd_ioctl.
355 */
356static const struct tty_operations master_pty_ops_bsd = {
357 .install = pty_install,
Alan Cox3e8e88c2008-04-30 00:54:10 -0700358 .open = pty_open,
359 .close = pty_close,
360 .write = pty_write,
361 .write_room = pty_write_room,
362 .flush_buffer = pty_flush_buffer,
363 .chars_in_buffer = pty_chars_in_buffer,
364 .unthrottle = pty_unthrottle,
365 .set_termios = pty_set_termios,
366 .ioctl = pty_bsd_ioctl,
Alan Coxfc6f6232009-01-02 13:43:17 +0000367 .resize = pty_resize
Alan Cox3e8e88c2008-04-30 00:54:10 -0700368};
369
Linus Torvalds342a5972009-09-30 07:49:40 -0700370static const struct tty_operations slave_pty_ops_bsd = {
371 .install = pty_install,
372 .open = pty_open,
373 .close = pty_close,
374 .write = pty_write,
375 .write_room = pty_write_room,
376 .flush_buffer = pty_flush_buffer,
377 .chars_in_buffer = pty_chars_in_buffer,
378 .unthrottle = pty_unthrottle,
379 .set_termios = pty_set_termios,
380 .resize = pty_resize
381};
382
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383static void __init legacy_pty_init(void)
384{
Linus Torvalds342a5972009-09-30 07:49:40 -0700385 struct tty_driver *pty_driver, *pty_slave_driver;
386
Kay Sieversdc8c8582007-08-15 12:25:38 +0200387 if (legacy_count <= 0)
388 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389
Kay Sieversdc8c8582007-08-15 12:25:38 +0200390 pty_driver = alloc_tty_driver(legacy_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 if (!pty_driver)
392 panic("Couldn't allocate pty driver");
393
Kay Sieversdc8c8582007-08-15 12:25:38 +0200394 pty_slave_driver = alloc_tty_driver(legacy_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 if (!pty_slave_driver)
396 panic("Couldn't allocate pty slave driver");
397
398 pty_driver->owner = THIS_MODULE;
399 pty_driver->driver_name = "pty_master";
400 pty_driver->name = "pty";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 pty_driver->major = PTY_MASTER_MAJOR;
402 pty_driver->minor_start = 0;
403 pty_driver->type = TTY_DRIVER_TYPE_PTY;
404 pty_driver->subtype = PTY_TYPE_MASTER;
405 pty_driver->init_termios = tty_std_termios;
406 pty_driver->init_termios.c_iflag = 0;
407 pty_driver->init_termios.c_oflag = 0;
408 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
409 pty_driver->init_termios.c_lflag = 0;
Alan Cox606d0992006-12-08 02:38:45 -0800410 pty_driver->init_termios.c_ispeed = 38400;
411 pty_driver->init_termios.c_ospeed = 38400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
413 pty_driver->other = pty_slave_driver;
Linus Torvalds342a5972009-09-30 07:49:40 -0700414 tty_set_operations(pty_driver, &master_pty_ops_bsd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415
416 pty_slave_driver->owner = THIS_MODULE;
417 pty_slave_driver->driver_name = "pty_slave";
418 pty_slave_driver->name = "ttyp";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 pty_slave_driver->major = PTY_SLAVE_MAJOR;
420 pty_slave_driver->minor_start = 0;
421 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
422 pty_slave_driver->subtype = PTY_TYPE_SLAVE;
423 pty_slave_driver->init_termios = tty_std_termios;
424 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
Alan Cox606d0992006-12-08 02:38:45 -0800425 pty_slave_driver->init_termios.c_ispeed = 38400;
426 pty_slave_driver->init_termios.c_ospeed = 38400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
428 TTY_DRIVER_REAL_RAW;
429 pty_slave_driver->other = pty_driver;
Linus Torvalds342a5972009-09-30 07:49:40 -0700430 tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431
432 if (tty_register_driver(pty_driver))
433 panic("Couldn't register pty driver");
434 if (tty_register_driver(pty_slave_driver))
435 panic("Couldn't register pty slave driver");
436}
437#else
438static inline void legacy_pty_init(void) { }
439#endif
440
441/* Unix98 devices */
442#ifdef CONFIG_UNIX98_PTYS
443/*
444 * sysctl support for setting limits on the number of Unix98 ptys allocated.
445 * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
446 */
447int pty_limit = NR_UNIX98_PTY_DEFAULT;
Alan Coxfe9cd962008-10-13 10:43:38 +0100448static int pty_limit_min;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449static int pty_limit_max = NR_UNIX98_PTY_MAX;
Alan Coxfe9cd962008-10-13 10:43:38 +0100450static int pty_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451
Alan Coxd81ed102008-10-13 10:41:42 +0100452static struct cdev ptmx_cdev;
453
Eric W. Biederman35834ca2007-10-18 03:05:31 -0700454static struct ctl_table pty_table[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 .procname = "max",
457 .maxlen = sizeof(int),
458 .mode = 0644,
459 .data = &pty_limit,
Eric W. Biederman6d456112009-11-16 03:11:48 -0800460 .proc_handler = proc_dointvec_minmax,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 .extra1 = &pty_limit_min,
462 .extra2 = &pty_limit_max,
463 }, {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 .procname = "nr",
465 .maxlen = sizeof(int),
466 .mode = 0444,
Alan Coxbf970ee2008-10-13 10:42:39 +0100467 .data = &pty_count,
Eric W. Biederman6d456112009-11-16 03:11:48 -0800468 .proc_handler = proc_dointvec,
Eric W. Biederman894d2492009-11-05 14:34:02 -0800469 },
470 {}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471};
472
Eric W. Biederman35834ca2007-10-18 03:05:31 -0700473static struct ctl_table pty_kern_table[] = {
474 {
Eric W. Biederman35834ca2007-10-18 03:05:31 -0700475 .procname = "pty",
476 .mode = 0555,
477 .child = pty_table,
478 },
479 {}
480};
481
482static struct ctl_table pty_root_table[] = {
483 {
Eric W. Biederman35834ca2007-10-18 03:05:31 -0700484 .procname = "kernel",
485 .mode = 0555,
486 .child = pty_kern_table,
487 },
488 {}
489};
490
491
Alan Cox6caa76b2011-02-14 16:27:22 +0000492static int pty_unix98_ioctl(struct tty_struct *tty,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 unsigned int cmd, unsigned long arg)
494{
495 switch (cmd) {
496 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
497 return pty_set_lock(tty, (int __user *)arg);
498 case TIOCGPTN: /* Get PT Number */
499 return put_user(tty->index, (unsigned int __user *)arg);
hyc@symas.com26df6d12010-06-22 10:14:49 -0700500 case TIOCSIG: /* Send signal to other side of pty */
501 return pty_signal(tty, (int) arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 }
503
504 return -ENOIOCTLCMD;
505}
506
Alan Cox99f1fe12008-10-13 10:42:00 +0100507/**
508 * ptm_unix98_lookup - find a pty master
509 * @driver: ptm driver
510 * @idx: tty index
511 *
512 * Look up a pty master device. Called under the tty_mutex for now.
513 * This provides our locking.
514 */
515
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100516static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
517 struct inode *ptm_inode, int idx)
Alan Cox99f1fe12008-10-13 10:42:00 +0100518{
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100519 struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
Alan Cox99f1fe12008-10-13 10:42:00 +0100520 if (tty)
521 tty = tty->link;
522 return tty;
523}
524
525/**
526 * pts_unix98_lookup - find a pty slave
527 * @driver: pts driver
528 * @idx: tty index
529 *
530 * Look up a pty master device. Called under the tty_mutex for now.
531 * This provides our locking.
532 */
533
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100534static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
535 struct inode *pts_inode, int idx)
Alan Cox99f1fe12008-10-13 10:42:00 +0100536{
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100537 struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
Alan Cox99f1fe12008-10-13 10:42:00 +0100538 /* Master must be open before slave */
539 if (!tty)
540 return ERR_PTR(-EIO);
541 return tty;
542}
543
Alan Coxbf970ee2008-10-13 10:42:39 +0100544static void pty_unix98_shutdown(struct tty_struct *tty)
Alan Coxfeebed62008-10-13 10:41:30 +0100545{
546 /* We have our own method as we don't use the tty index */
547 kfree(tty->termios);
Alan Coxfeebed62008-10-13 10:41:30 +0100548}
549
Alan Cox8b0a88d2008-10-13 10:42:19 +0100550/* We have no need to install and remove our tty objects as devpts does all
551 the work for us */
552
Alan Coxbf970ee2008-10-13 10:42:39 +0100553static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
Alan Cox8b0a88d2008-10-13 10:42:19 +0100554{
Alan Coxbf970ee2008-10-13 10:42:39 +0100555 struct tty_struct *o_tty;
556 int idx = tty->index;
557
558 o_tty = alloc_tty_struct();
559 if (!o_tty)
560 return -ENOMEM;
561 if (!try_module_get(driver->other->owner)) {
562 /* This cannot in fact currently happen */
Jiri Slabyc18d77a2011-03-23 10:48:34 +0100563 goto err_free_tty;
Alan Coxbf970ee2008-10-13 10:42:39 +0100564 }
565 initialize_tty_struct(o_tty, driver->other, idx);
566
Alan Cox8dff04e2008-10-13 10:43:58 +0100567 tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
Alan Coxbf970ee2008-10-13 10:42:39 +0100568 if (tty->termios == NULL)
Jiri Slabyc18d77a2011-03-23 10:48:34 +0100569 goto err_free_mem;
Alan Coxbf970ee2008-10-13 10:42:39 +0100570 *tty->termios = driver->init_termios;
Alan Cox8dff04e2008-10-13 10:43:58 +0100571 tty->termios_locked = tty->termios + 1;
572
573 o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
Alan Coxbf970ee2008-10-13 10:42:39 +0100574 if (o_tty->termios == NULL)
Jiri Slabyc18d77a2011-03-23 10:48:34 +0100575 goto err_free_mem;
Alan Coxbf970ee2008-10-13 10:42:39 +0100576 *o_tty->termios = driver->other->init_termios;
Alan Cox8dff04e2008-10-13 10:43:58 +0100577 o_tty->termios_locked = o_tty->termios + 1;
Alan Coxbf970ee2008-10-13 10:42:39 +0100578
579 tty_driver_kref_get(driver->other);
580 if (driver->subtype == PTY_TYPE_MASTER)
581 o_tty->count++;
582 /* Establish the links in both directions */
583 tty->link = o_tty;
584 o_tty->link = tty;
585 /*
586 * All structures have been allocated, so now we install them.
587 * Failures after this point use release_tty to clean up, so
588 * there's no need to null out the local pointers.
589 */
590 tty_driver_kref_get(driver);
591 tty->count++;
592 pty_count++;
Alan Cox8b0a88d2008-10-13 10:42:19 +0100593 return 0;
Jiri Slabyc18d77a2011-03-23 10:48:34 +0100594err_free_mem:
Alan Cox8dff04e2008-10-13 10:43:58 +0100595 kfree(o_tty->termios);
Alan Cox8dff04e2008-10-13 10:43:58 +0100596 kfree(tty->termios);
Jiri Slabyc18d77a2011-03-23 10:48:34 +0100597 module_put(o_tty->driver->owner);
598err_free_tty:
599 free_tty_struct(o_tty);
Alan Coxbf970ee2008-10-13 10:42:39 +0100600 return -ENOMEM;
Alan Cox8b0a88d2008-10-13 10:42:19 +0100601}
602
Alan Coxbf970ee2008-10-13 10:42:39 +0100603static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
Alan Cox8b0a88d2008-10-13 10:42:19 +0100604{
Alan Coxbf970ee2008-10-13 10:42:39 +0100605 pty_count--;
Alan Cox8b0a88d2008-10-13 10:42:19 +0100606}
607
Alan Coxfeebed62008-10-13 10:41:30 +0100608static const struct tty_operations ptm_unix98_ops = {
Alan Cox99f1fe12008-10-13 10:42:00 +0100609 .lookup = ptm_unix98_lookup,
Alan Coxbf970ee2008-10-13 10:42:39 +0100610 .install = pty_unix98_install,
611 .remove = pty_unix98_remove,
Alan Cox3e8e88c2008-04-30 00:54:10 -0700612 .open = pty_open,
613 .close = pty_close,
614 .write = pty_write,
615 .write_room = pty_write_room,
616 .flush_buffer = pty_flush_buffer,
617 .chars_in_buffer = pty_chars_in_buffer,
618 .unthrottle = pty_unthrottle,
619 .set_termios = pty_set_termios,
Alan Coxfeebed62008-10-13 10:41:30 +0100620 .ioctl = pty_unix98_ioctl,
Alan Coxfc6f6232009-01-02 13:43:17 +0000621 .shutdown = pty_unix98_shutdown,
622 .resize = pty_resize
Alan Cox3e8e88c2008-04-30 00:54:10 -0700623};
624
Alan Cox99f1fe12008-10-13 10:42:00 +0100625static const struct tty_operations pty_unix98_ops = {
626 .lookup = pts_unix98_lookup,
Alan Coxbf970ee2008-10-13 10:42:39 +0100627 .install = pty_unix98_install,
628 .remove = pty_unix98_remove,
Alan Cox99f1fe12008-10-13 10:42:00 +0100629 .open = pty_open,
630 .close = pty_close,
631 .write = pty_write,
632 .write_room = pty_write_room,
633 .flush_buffer = pty_flush_buffer,
634 .chars_in_buffer = pty_chars_in_buffer,
635 .unthrottle = pty_unthrottle,
636 .set_termios = pty_set_termios,
Alan Coxbf970ee2008-10-13 10:42:39 +0100637 .shutdown = pty_unix98_shutdown
Alan Cox99f1fe12008-10-13 10:42:00 +0100638};
Alan Coxd81ed102008-10-13 10:41:42 +0100639
640/**
641 * ptmx_open - open a unix 98 pty master
642 * @inode: inode of device file
643 * @filp: file pointer to tty
644 *
645 * Allocate a unix98 pty master device from the ptmx driver.
646 *
647 * Locking: tty_mutex protects the init_dev work. tty->count should
648 * protect the rest.
649 * allocated_ptys_lock handles the list of free pty numbers
650 */
651
Arnd Bergmann64ba3dc2010-06-01 22:53:02 +0200652static int ptmx_open(struct inode *inode, struct file *filp)
Alan Coxd81ed102008-10-13 10:41:42 +0100653{
654 struct tty_struct *tty;
655 int retval;
656 int index;
657
658 nonseekable_open(inode, filp);
659
660 /* find a device that is not in use. */
Arnd Bergmann64ba3dc2010-06-01 22:53:02 +0200661 tty_lock();
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100662 index = devpts_new_index(inode);
Arnd Bergmann64ba3dc2010-06-01 22:53:02 +0200663 tty_unlock();
Alan Coxd81ed102008-10-13 10:41:42 +0100664 if (index < 0)
665 return index;
666
667 mutex_lock(&tty_mutex);
Arnd Bergmann64ba3dc2010-06-01 22:53:02 +0200668 tty_lock();
Alan Cox73ec06f2008-10-13 10:42:29 +0100669 tty = tty_init_dev(ptm_driver, index, 1);
Alan Coxd81ed102008-10-13 10:41:42 +0100670 mutex_unlock(&tty_mutex);
671
Alan Cox73ec06f2008-10-13 10:42:29 +0100672 if (IS_ERR(tty)) {
673 retval = PTR_ERR(tty);
Alan Coxd81ed102008-10-13 10:41:42 +0100674 goto out;
Alan Cox73ec06f2008-10-13 10:42:29 +0100675 }
Alan Coxd81ed102008-10-13 10:41:42 +0100676
677 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
Nick Pigginee2ffa02010-08-18 04:37:35 +1000678
Pekka Enbergf573bd12010-08-24 07:48:34 +0300679 retval = tty_add_file(tty, filp);
680 if (retval)
681 goto out;
Alan Coxd81ed102008-10-13 10:41:42 +0100682
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100683 retval = devpts_pty_new(inode, tty->link);
Alan Coxd81ed102008-10-13 10:41:42 +0100684 if (retval)
685 goto out1;
686
687 retval = ptm_driver->ops->open(tty, filp);
Arnd Bergmann64ba3dc2010-06-01 22:53:02 +0200688 if (retval)
689 goto out2;
Alan Coxd81ed102008-10-13 10:41:42 +0100690out1:
Arnd Bergmann64ba3dc2010-06-01 22:53:02 +0200691 tty_unlock();
692 return retval;
693out2:
694 tty_unlock();
Alan Coxeeb89d92009-11-30 13:18:29 +0000695 tty_release(inode, filp);
Alan Coxd81ed102008-10-13 10:41:42 +0100696 return retval;
697out:
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100698 devpts_kill_index(inode, index);
Arnd Bergmannec79d602010-06-01 22:53:01 +0200699 tty_unlock();
Arnd Bergmann64ba3dc2010-06-01 22:53:02 +0200700 return retval;
Alan Coxd81ed102008-10-13 10:41:42 +0100701}
702
703static struct file_operations ptmx_fops;
704
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705static void __init unix98_pty_init(void)
706{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
708 if (!ptm_driver)
709 panic("Couldn't allocate Unix98 ptm driver");
710 pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
711 if (!pts_driver)
712 panic("Couldn't allocate Unix98 pts driver");
713
714 ptm_driver->owner = THIS_MODULE;
715 ptm_driver->driver_name = "pty_master";
716 ptm_driver->name = "ptm";
717 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
718 ptm_driver->minor_start = 0;
719 ptm_driver->type = TTY_DRIVER_TYPE_PTY;
720 ptm_driver->subtype = PTY_TYPE_MASTER;
721 ptm_driver->init_termios = tty_std_termios;
722 ptm_driver->init_termios.c_iflag = 0;
723 ptm_driver->init_termios.c_oflag = 0;
724 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
725 ptm_driver->init_termios.c_lflag = 0;
Alan Cox606d0992006-12-08 02:38:45 -0800726 ptm_driver->init_termios.c_ispeed = 38400;
727 ptm_driver->init_termios.c_ospeed = 38400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
Greg Kroah-Hartman331b8312005-06-20 21:15:16 -0700729 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 ptm_driver->other = pts_driver;
Alan Coxfeebed62008-10-13 10:41:30 +0100731 tty_set_operations(ptm_driver, &ptm_unix98_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732
733 pts_driver->owner = THIS_MODULE;
734 pts_driver->driver_name = "pty_slave";
735 pts_driver->name = "pts";
736 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
737 pts_driver->minor_start = 0;
738 pts_driver->type = TTY_DRIVER_TYPE_PTY;
739 pts_driver->subtype = PTY_TYPE_SLAVE;
740 pts_driver->init_termios = tty_std_termios;
741 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
Alan Cox606d0992006-12-08 02:38:45 -0800742 pts_driver->init_termios.c_ispeed = 38400;
743 pts_driver->init_termios.c_ospeed = 38400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
Greg Kroah-Hartman331b8312005-06-20 21:15:16 -0700745 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 pts_driver->other = ptm_driver;
Alan Cox99f1fe12008-10-13 10:42:00 +0100747 tty_set_operations(pts_driver, &pty_unix98_ops);
Alan Coxfe9cd962008-10-13 10:43:38 +0100748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 if (tty_register_driver(ptm_driver))
750 panic("Couldn't register Unix98 ptm driver");
751 if (tty_register_driver(pts_driver))
752 panic("Couldn't register Unix98 pts driver");
753
Alan Coxfe9cd962008-10-13 10:43:38 +0100754 register_sysctl_table(pty_root_table);
Alan Coxd81ed102008-10-13 10:41:42 +0100755
756 /* Now create the /dev/ptmx special device */
757 tty_default_fops(&ptmx_fops);
758 ptmx_fops.open = ptmx_open;
759
760 cdev_init(&ptmx_cdev, &ptmx_fops);
761 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
762 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
763 panic("Couldn't register /dev/ptmx driver\n");
764 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765}
Alan Coxd81ed102008-10-13 10:41:42 +0100766
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767#else
768static inline void unix98_pty_init(void) { }
769#endif
770
771static int __init pty_init(void)
772{
773 legacy_pty_init();
774 unix98_pty_init();
775 return 0;
776}
777module_init(pty_init);