blob: 31038a0052a2c3e007a4e792f2945ff015a7856e [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>
21#include <linux/string.h>
22#include <linux/major.h>
23#include <linux/mm.h>
24#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/sysctl.h>
Alan Coxd81ed102008-10-13 10:41:42 +010026#include <linux/device.h>
Alan Coxfe9cd962008-10-13 10:43:38 +010027#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/bitops.h>
29#include <linux/devpts_fs.h>
30
Alan Coxfe9cd962008-10-13 10:43:38 +010031#include <asm/system.h>
32
Linus Torvalds1da177e2005-04-16 15:20:36 -070033/* These are global because they are accessed in tty_io.c */
34#ifdef CONFIG_UNIX98_PTYS
Roel Kluinda2bdf92009-01-07 18:09:15 -080035static struct tty_driver *ptm_driver;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036static struct tty_driver *pts_driver;
37#endif
38
Alan Coxfe9cd962008-10-13 10:43:38 +010039static void pty_close(struct tty_struct *tty, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -070040{
Alan Coxfe9cd962008-10-13 10:43:38 +010041 BUG_ON(!tty);
42 if (tty->driver->subtype == PTY_TYPE_MASTER)
43 WARN_ON(tty->count > 1);
44 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 if (tty->count > 2)
46 return;
47 }
48 wake_up_interruptible(&tty->read_wait);
49 wake_up_interruptible(&tty->write_wait);
50 tty->packet = 0;
51 if (!tty->link)
52 return;
53 tty->link->packet = 0;
54 set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
55 wake_up_interruptible(&tty->link->read_wait);
56 wake_up_interruptible(&tty->link->write_wait);
57 if (tty->driver->subtype == PTY_TYPE_MASTER) {
58 set_bit(TTY_OTHER_CLOSED, &tty->flags);
59#ifdef CONFIG_UNIX98_PTYS
60 if (tty->driver == ptm_driver)
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +010061 devpts_pty_kill(tty->link);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062#endif
63 tty_vhangup(tty->link);
64 }
65}
66
67/*
68 * The unthrottle routine is called by the line discipline to signal
69 * that it can receive more characters. For PTY's, the TTY_THROTTLED
70 * flag is always set, to force the line discipline to always call the
Alan Coxfe9cd962008-10-13 10:43:38 +010071 * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 * characters in the queue. This is necessary since each time this
73 * happens, we need to wake up any sleeping processes that could be
74 * (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
75 * for the pty buffer to be drained.
76 */
Alan Coxfe9cd962008-10-13 10:43:38 +010077static void pty_unthrottle(struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -070078{
79 struct tty_struct *o_tty = tty->link;
80
81 if (!o_tty)
82 return;
83
84 tty_wakeup(o_tty);
85 set_bit(TTY_THROTTLED, &tty->flags);
86}
87
88/*
Alan Coxfe9cd962008-10-13 10:43:38 +010089 * WSH 05/24/97: modified to
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 * (1) use space in tty->flip instead of a shared temp buffer
91 * The flip buffers aren't being used for a pty, so there's lots
92 * of space available. The buffer is protected by a per-pty
93 * semaphore that should almost never come under contention.
94 * (2) avoid redundant copying for cases where count >> receive_room
95 * N.B. Calls from user space may now return an error code instead of
96 * a count.
97 *
98 * FIXME: Our pty_write method is called with our ldisc lock held but
99 * not our partners. We can't just take the other one blindly without
Paul Fulghum817d6d32006-06-28 04:26:47 -0700100 * risking deadlocks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 */
Alan Coxfe9cd962008-10-13 10:43:38 +0100102static int pty_write(struct tty_struct *tty, const unsigned char *buf,
103 int count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104{
105 struct tty_struct *to = tty->link;
106 int c;
107
108 if (!to || tty->stopped)
109 return 0;
110
Alan Cox33f0f882006-01-09 20:54:13 -0800111 c = to->receive_room;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 if (c > count)
113 c = count;
Alan Coxa352def2008-07-16 21:53:12 +0100114 to->ldisc.ops->receive_buf(to, buf, NULL, c);
Alan Coxfe9cd962008-10-13 10:43:38 +0100115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 return c;
117}
118
119static int pty_write_room(struct tty_struct *tty)
120{
121 struct tty_struct *to = tty->link;
122
123 if (!to || tty->stopped)
124 return 0;
125
Alan Cox33f0f882006-01-09 20:54:13 -0800126 return to->receive_room;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127}
128
129/*
130 * WSH 05/24/97: Modified for asymmetric MASTER/SLAVE behavior
Alan Coxfe9cd962008-10-13 10:43:38 +0100131 * The chars_in_buffer() value is used by the ldisc select() function
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 * to hold off writing when chars_in_buffer > WAKEUP_CHARS (== 256).
133 * The pty driver chars_in_buffer() Master/Slave must behave differently:
134 *
135 * The Master side needs to allow typed-ahead commands to accumulate
136 * while being canonicalized, so we report "our buffer" as empty until
137 * some threshold is reached, and then report the count. (Any count >
Alan Coxfe9cd962008-10-13 10:43:38 +0100138 * WAKEUP_CHARS is regarded by select() as "full".) To avoid deadlock
139 * the count returned must be 0 if no canonical data is available to be
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 * read. (The N_TTY ldisc.chars_in_buffer now knows this.)
Alan Coxfe9cd962008-10-13 10:43:38 +0100141 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 * The Slave side passes all characters in raw mode to the Master side's
143 * buffer where they can be read immediately, so in this case we can
144 * return the true count in the buffer.
145 */
146static int pty_chars_in_buffer(struct tty_struct *tty)
147{
148 struct tty_struct *to = tty->link;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 int count;
150
151 /* We should get the line discipline lock for "tty->link" */
Alan Coxa352def2008-07-16 21:53:12 +0100152 if (!to || !to->ldisc.ops->chars_in_buffer)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 return 0;
154
155 /* The ldisc must report 0 if no characters available to be read */
Alan Coxa352def2008-07-16 21:53:12 +0100156 count = to->ldisc.ops->chars_in_buffer(to);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
Alan Coxfe9cd962008-10-13 10:43:38 +0100158 if (tty->driver->subtype == PTY_TYPE_SLAVE)
159 return count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160
Alan Coxfe9cd962008-10-13 10:43:38 +0100161 /* Master side driver ... if the other side's read buffer is less than
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 * half full, return 0 to allow writers to proceed; otherwise return
Alan Coxfe9cd962008-10-13 10:43:38 +0100163 * the count. This leaves a comfortable margin to avoid overflow,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 * and still allows half a buffer's worth of typed-ahead commands.
165 */
Alan Coxfe9cd962008-10-13 10:43:38 +0100166 return (count < N_TTY_BUF_SIZE/2) ? 0 : count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167}
168
169/* Set the lock flag on a pty */
Alan Coxfe9cd962008-10-13 10:43:38 +0100170static int pty_set_lock(struct tty_struct *tty, int __user *arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171{
172 int val;
Alan Coxfe9cd962008-10-13 10:43:38 +0100173 if (get_user(val, arg))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 return -EFAULT;
175 if (val)
176 set_bit(TTY_PTY_LOCK, &tty->flags);
177 else
178 clear_bit(TTY_PTY_LOCK, &tty->flags);
179 return 0;
180}
181
182static void pty_flush_buffer(struct tty_struct *tty)
183{
184 struct tty_struct *to = tty->link;
Alan Cox04f378b2008-04-30 00:53:29 -0700185 unsigned long flags;
Alan Coxfe9cd962008-10-13 10:43:38 +0100186
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 if (!to)
188 return;
Alan Coxfe9cd962008-10-13 10:43:38 +0100189
Alan Coxa352def2008-07-16 21:53:12 +0100190 if (to->ldisc.ops->flush_buffer)
191 to->ldisc.ops->flush_buffer(to);
Alan Coxfe9cd962008-10-13 10:43:38 +0100192
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 if (to->packet) {
Alan Cox04f378b2008-04-30 00:53:29 -0700194 spin_lock_irqsave(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
196 wake_up_interruptible(&to->read_wait);
Alan Cox04f378b2008-04-30 00:53:29 -0700197 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 }
199}
200
Alan Coxfe9cd962008-10-13 10:43:38 +0100201static int pty_open(struct tty_struct *tty, struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202{
203 int retval = -ENODEV;
204
205 if (!tty || !tty->link)
206 goto out;
207
208 retval = -EIO;
209 if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
210 goto out;
211 if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
212 goto out;
213 if (tty->link->count != 1)
214 goto out;
215
216 clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
217 set_bit(TTY_THROTTLED, &tty->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 retval = 0;
219out:
220 return retval;
221}
222
Alan Coxfe9cd962008-10-13 10:43:38 +0100223static void pty_set_termios(struct tty_struct *tty,
224 struct ktermios *old_termios)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225{
Alan Coxfe9cd962008-10-13 10:43:38 +0100226 tty->termios->c_cflag &= ~(CSIZE | PARENB);
227 tty->termios->c_cflag |= (CS8 | CREAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228}
229
Alan Coxfc6f6232009-01-02 13:43:17 +0000230/**
231 * pty_do_resize - resize event
232 * @tty: tty being resized
Alan Coxc774bda2009-01-11 19:46:49 +0000233 * @ws: window size being set.
Alan Coxfc6f6232009-01-02 13:43:17 +0000234 *
235 * Update the termios variables and send the neccessary signals to
236 * peform a terminal resize correctly
237 */
238
239int pty_resize(struct tty_struct *tty, struct winsize *ws)
240{
241 struct pid *pgrp, *rpgrp;
242 unsigned long flags;
243 struct tty_struct *pty = tty->link;
244
245 /* For a PTY we need to lock the tty side */
246 mutex_lock(&tty->termios_mutex);
247 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
248 goto done;
249
250 /* Get the PID values and reference them so we can
251 avoid holding the tty ctrl lock while sending signals.
252 We need to lock these individually however. */
253
254 spin_lock_irqsave(&tty->ctrl_lock, flags);
255 pgrp = get_pid(tty->pgrp);
256 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
257
258 spin_lock_irqsave(&pty->ctrl_lock, flags);
259 rpgrp = get_pid(pty->pgrp);
260 spin_unlock_irqrestore(&pty->ctrl_lock, flags);
261
262 if (pgrp)
263 kill_pgrp(pgrp, SIGWINCH, 1);
264 if (rpgrp != pgrp && rpgrp)
265 kill_pgrp(rpgrp, SIGWINCH, 1);
266
267 put_pid(pgrp);
268 put_pid(rpgrp);
269
270 tty->winsize = *ws;
271 pty->winsize = *ws; /* Never used so will go away soon */
272done:
273 mutex_unlock(&tty->termios_mutex);
274 return 0;
275}
276
Alan Coxbf970ee2008-10-13 10:42:39 +0100277static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
278{
279 struct tty_struct *o_tty;
280 int idx = tty->index;
281 int retval;
282
283 o_tty = alloc_tty_struct();
284 if (!o_tty)
285 return -ENOMEM;
286 if (!try_module_get(driver->other->owner)) {
287 /* This cannot in fact currently happen */
288 free_tty_struct(o_tty);
289 return -ENOMEM;
290 }
291 initialize_tty_struct(o_tty, driver->other, idx);
292
293 /* We always use new tty termios data so we can do this
294 the easy way .. */
295 retval = tty_init_termios(tty);
296 if (retval)
297 goto free_mem_out;
298
299 retval = tty_init_termios(o_tty);
300 if (retval) {
301 tty_free_termios(tty);
302 goto free_mem_out;
303 }
Alan Coxfe9cd962008-10-13 10:43:38 +0100304
Alan Coxbf970ee2008-10-13 10:42:39 +0100305 /*
306 * Everything allocated ... set up the o_tty structure.
307 */
308 driver->other->ttys[idx] = o_tty;
309 tty_driver_kref_get(driver->other);
310 if (driver->subtype == PTY_TYPE_MASTER)
311 o_tty->count++;
312 /* Establish the links in both directions */
313 tty->link = o_tty;
314 o_tty->link = tty;
315
316 tty_driver_kref_get(driver);
317 tty->count++;
318 driver->ttys[idx] = tty;
319 return 0;
320free_mem_out:
321 module_put(o_tty->driver->owner);
322 free_tty_struct(o_tty);
323 return -ENOMEM;
324}
325
326
Jeff Dikeb68e31d2006-10-02 02:17:18 -0700327static const struct tty_operations pty_ops = {
Alan Coxbf970ee2008-10-13 10:42:39 +0100328 .install = pty_install,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 .open = pty_open,
330 .close = pty_close,
331 .write = pty_write,
332 .write_room = pty_write_room,
333 .flush_buffer = pty_flush_buffer,
334 .chars_in_buffer = pty_chars_in_buffer,
335 .unthrottle = pty_unthrottle,
336 .set_termios = pty_set_termios,
Alan Coxfc6f6232009-01-02 13:43:17 +0000337 .resize = pty_resize
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338};
339
340/* Traditional BSD devices */
341#ifdef CONFIG_LEGACY_PTYS
342static struct tty_driver *pty_driver, *pty_slave_driver;
343
344static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
345 unsigned int cmd, unsigned long arg)
346{
347 switch (cmd) {
348 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
349 return pty_set_lock(tty, (int __user *) arg);
350 }
351 return -ENOIOCTLCMD;
352}
353
Kay Sieversdc8c8582007-08-15 12:25:38 +0200354static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
355module_param(legacy_count, int, 0);
356
Alan Cox3e8e88c2008-04-30 00:54:10 -0700357static const struct tty_operations pty_ops_bsd = {
358 .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 Torvalds1da177e2005-04-16 15:20:36 -0700370static void __init legacy_pty_init(void)
371{
Kay Sieversdc8c8582007-08-15 12:25:38 +0200372 if (legacy_count <= 0)
373 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374
Kay Sieversdc8c8582007-08-15 12:25:38 +0200375 pty_driver = alloc_tty_driver(legacy_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 if (!pty_driver)
377 panic("Couldn't allocate pty driver");
378
Kay Sieversdc8c8582007-08-15 12:25:38 +0200379 pty_slave_driver = alloc_tty_driver(legacy_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 if (!pty_slave_driver)
381 panic("Couldn't allocate pty slave driver");
382
383 pty_driver->owner = THIS_MODULE;
384 pty_driver->driver_name = "pty_master";
385 pty_driver->name = "pty";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 pty_driver->major = PTY_MASTER_MAJOR;
387 pty_driver->minor_start = 0;
388 pty_driver->type = TTY_DRIVER_TYPE_PTY;
389 pty_driver->subtype = PTY_TYPE_MASTER;
390 pty_driver->init_termios = tty_std_termios;
391 pty_driver->init_termios.c_iflag = 0;
392 pty_driver->init_termios.c_oflag = 0;
393 pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
394 pty_driver->init_termios.c_lflag = 0;
Alan Cox606d0992006-12-08 02:38:45 -0800395 pty_driver->init_termios.c_ispeed = 38400;
396 pty_driver->init_termios.c_ospeed = 38400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 pty_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW;
398 pty_driver->other = pty_slave_driver;
399 tty_set_operations(pty_driver, &pty_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400
401 pty_slave_driver->owner = THIS_MODULE;
402 pty_slave_driver->driver_name = "pty_slave";
403 pty_slave_driver->name = "ttyp";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 pty_slave_driver->major = PTY_SLAVE_MAJOR;
405 pty_slave_driver->minor_start = 0;
406 pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
407 pty_slave_driver->subtype = PTY_TYPE_SLAVE;
408 pty_slave_driver->init_termios = tty_std_termios;
409 pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
Alan Cox606d0992006-12-08 02:38:45 -0800410 pty_slave_driver->init_termios.c_ispeed = 38400;
411 pty_slave_driver->init_termios.c_ospeed = 38400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 pty_slave_driver->flags = TTY_DRIVER_RESET_TERMIOS |
413 TTY_DRIVER_REAL_RAW;
414 pty_slave_driver->other = pty_driver;
415 tty_set_operations(pty_slave_driver, &pty_ops);
416
417 if (tty_register_driver(pty_driver))
418 panic("Couldn't register pty driver");
419 if (tty_register_driver(pty_slave_driver))
420 panic("Couldn't register pty slave driver");
421}
422#else
423static inline void legacy_pty_init(void) { }
424#endif
425
426/* Unix98 devices */
427#ifdef CONFIG_UNIX98_PTYS
428/*
429 * sysctl support for setting limits on the number of Unix98 ptys allocated.
430 * Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
431 */
432int pty_limit = NR_UNIX98_PTY_DEFAULT;
Alan Coxfe9cd962008-10-13 10:43:38 +0100433static int pty_limit_min;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434static int pty_limit_max = NR_UNIX98_PTY_MAX;
Alan Coxfe9cd962008-10-13 10:43:38 +0100435static int pty_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436
Alan Coxd81ed102008-10-13 10:41:42 +0100437static struct cdev ptmx_cdev;
438
Eric W. Biederman35834ca2007-10-18 03:05:31 -0700439static struct ctl_table pty_table[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 {
441 .ctl_name = PTY_MAX,
442 .procname = "max",
443 .maxlen = sizeof(int),
444 .mode = 0644,
445 .data = &pty_limit,
446 .proc_handler = &proc_dointvec_minmax,
447 .strategy = &sysctl_intvec,
448 .extra1 = &pty_limit_min,
449 .extra2 = &pty_limit_max,
450 }, {
451 .ctl_name = PTY_NR,
452 .procname = "nr",
453 .maxlen = sizeof(int),
454 .mode = 0444,
Alan Coxbf970ee2008-10-13 10:42:39 +0100455 .data = &pty_count,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 .proc_handler = &proc_dointvec,
457 }, {
458 .ctl_name = 0
459 }
460};
461
Eric W. Biederman35834ca2007-10-18 03:05:31 -0700462static struct ctl_table pty_kern_table[] = {
463 {
464 .ctl_name = KERN_PTY,
465 .procname = "pty",
466 .mode = 0555,
467 .child = pty_table,
468 },
469 {}
470};
471
472static struct ctl_table pty_root_table[] = {
473 {
474 .ctl_name = CTL_KERN,
475 .procname = "kernel",
476 .mode = 0555,
477 .child = pty_kern_table,
478 },
479 {}
480};
481
482
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
484 unsigned int cmd, unsigned long arg)
485{
486 switch (cmd) {
487 case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
488 return pty_set_lock(tty, (int __user *)arg);
489 case TIOCGPTN: /* Get PT Number */
490 return put_user(tty->index, (unsigned int __user *)arg);
491 }
492
493 return -ENOIOCTLCMD;
494}
495
Alan Cox99f1fe12008-10-13 10:42:00 +0100496/**
497 * ptm_unix98_lookup - find a pty master
498 * @driver: ptm driver
499 * @idx: tty index
500 *
501 * Look up a pty master device. Called under the tty_mutex for now.
502 * This provides our locking.
503 */
504
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100505static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
506 struct inode *ptm_inode, int idx)
Alan Cox99f1fe12008-10-13 10:42:00 +0100507{
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100508 struct tty_struct *tty = devpts_get_tty(ptm_inode, idx);
Alan Cox99f1fe12008-10-13 10:42:00 +0100509 if (tty)
510 tty = tty->link;
511 return tty;
512}
513
514/**
515 * pts_unix98_lookup - find a pty slave
516 * @driver: pts driver
517 * @idx: tty index
518 *
519 * Look up a pty master device. Called under the tty_mutex for now.
520 * This provides our locking.
521 */
522
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100523static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
524 struct inode *pts_inode, int idx)
Alan Cox99f1fe12008-10-13 10:42:00 +0100525{
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100526 struct tty_struct *tty = devpts_get_tty(pts_inode, idx);
Alan Cox99f1fe12008-10-13 10:42:00 +0100527 /* Master must be open before slave */
528 if (!tty)
529 return ERR_PTR(-EIO);
530 return tty;
531}
532
Alan Coxbf970ee2008-10-13 10:42:39 +0100533static void pty_unix98_shutdown(struct tty_struct *tty)
Alan Coxfeebed62008-10-13 10:41:30 +0100534{
535 /* We have our own method as we don't use the tty index */
536 kfree(tty->termios);
Alan Coxfeebed62008-10-13 10:41:30 +0100537}
538
Alan Cox8b0a88d2008-10-13 10:42:19 +0100539/* We have no need to install and remove our tty objects as devpts does all
540 the work for us */
541
Alan Coxbf970ee2008-10-13 10:42:39 +0100542static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
Alan Cox8b0a88d2008-10-13 10:42:19 +0100543{
Alan Coxbf970ee2008-10-13 10:42:39 +0100544 struct tty_struct *o_tty;
545 int idx = tty->index;
546
547 o_tty = alloc_tty_struct();
548 if (!o_tty)
549 return -ENOMEM;
550 if (!try_module_get(driver->other->owner)) {
551 /* This cannot in fact currently happen */
552 free_tty_struct(o_tty);
553 return -ENOMEM;
554 }
555 initialize_tty_struct(o_tty, driver->other, idx);
556
Alan Cox8dff04e2008-10-13 10:43:58 +0100557 tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
Alan Coxbf970ee2008-10-13 10:42:39 +0100558 if (tty->termios == NULL)
559 goto free_mem_out;
560 *tty->termios = driver->init_termios;
Alan Cox8dff04e2008-10-13 10:43:58 +0100561 tty->termios_locked = tty->termios + 1;
562
563 o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
Alan Coxbf970ee2008-10-13 10:42:39 +0100564 if (o_tty->termios == NULL)
565 goto free_mem_out;
566 *o_tty->termios = driver->other->init_termios;
Alan Cox8dff04e2008-10-13 10:43:58 +0100567 o_tty->termios_locked = o_tty->termios + 1;
Alan Coxbf970ee2008-10-13 10:42:39 +0100568
569 tty_driver_kref_get(driver->other);
570 if (driver->subtype == PTY_TYPE_MASTER)
571 o_tty->count++;
572 /* Establish the links in both directions */
573 tty->link = o_tty;
574 o_tty->link = tty;
575 /*
576 * All structures have been allocated, so now we install them.
577 * Failures after this point use release_tty to clean up, so
578 * there's no need to null out the local pointers.
579 */
580 tty_driver_kref_get(driver);
581 tty->count++;
582 pty_count++;
Alan Cox8b0a88d2008-10-13 10:42:19 +0100583 return 0;
Alan Coxbf970ee2008-10-13 10:42:39 +0100584free_mem_out:
Alan Cox8dff04e2008-10-13 10:43:58 +0100585 kfree(o_tty->termios);
Alan Coxbf970ee2008-10-13 10:42:39 +0100586 module_put(o_tty->driver->owner);
587 free_tty_struct(o_tty);
Alan Cox8dff04e2008-10-13 10:43:58 +0100588 kfree(tty->termios);
Alan Coxbf970ee2008-10-13 10:42:39 +0100589 return -ENOMEM;
Alan Cox8b0a88d2008-10-13 10:42:19 +0100590}
591
Alan Coxbf970ee2008-10-13 10:42:39 +0100592static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
Alan Cox8b0a88d2008-10-13 10:42:19 +0100593{
Alan Coxbf970ee2008-10-13 10:42:39 +0100594 pty_count--;
Alan Cox8b0a88d2008-10-13 10:42:19 +0100595}
596
Alan Coxfeebed62008-10-13 10:41:30 +0100597static const struct tty_operations ptm_unix98_ops = {
Alan Cox99f1fe12008-10-13 10:42:00 +0100598 .lookup = ptm_unix98_lookup,
Alan Coxbf970ee2008-10-13 10:42:39 +0100599 .install = pty_unix98_install,
600 .remove = pty_unix98_remove,
Alan Cox3e8e88c2008-04-30 00:54:10 -0700601 .open = pty_open,
602 .close = pty_close,
603 .write = pty_write,
604 .write_room = pty_write_room,
605 .flush_buffer = pty_flush_buffer,
606 .chars_in_buffer = pty_chars_in_buffer,
607 .unthrottle = pty_unthrottle,
608 .set_termios = pty_set_termios,
Alan Coxfeebed62008-10-13 10:41:30 +0100609 .ioctl = pty_unix98_ioctl,
Alan Coxfc6f6232009-01-02 13:43:17 +0000610 .shutdown = pty_unix98_shutdown,
611 .resize = pty_resize
Alan Cox3e8e88c2008-04-30 00:54:10 -0700612};
613
Alan Cox99f1fe12008-10-13 10:42:00 +0100614static const struct tty_operations pty_unix98_ops = {
615 .lookup = pts_unix98_lookup,
Alan Coxbf970ee2008-10-13 10:42:39 +0100616 .install = pty_unix98_install,
617 .remove = pty_unix98_remove,
Alan Cox99f1fe12008-10-13 10:42:00 +0100618 .open = pty_open,
619 .close = pty_close,
620 .write = pty_write,
621 .write_room = pty_write_room,
622 .flush_buffer = pty_flush_buffer,
623 .chars_in_buffer = pty_chars_in_buffer,
624 .unthrottle = pty_unthrottle,
625 .set_termios = pty_set_termios,
Alan Coxbf970ee2008-10-13 10:42:39 +0100626 .shutdown = pty_unix98_shutdown
Alan Cox99f1fe12008-10-13 10:42:00 +0100627};
Alan Coxd81ed102008-10-13 10:41:42 +0100628
629/**
630 * ptmx_open - open a unix 98 pty master
631 * @inode: inode of device file
632 * @filp: file pointer to tty
633 *
634 * Allocate a unix98 pty master device from the ptmx driver.
635 *
636 * Locking: tty_mutex protects the init_dev work. tty->count should
637 * protect the rest.
638 * allocated_ptys_lock handles the list of free pty numbers
639 */
640
641static int __ptmx_open(struct inode *inode, struct file *filp)
642{
643 struct tty_struct *tty;
644 int retval;
645 int index;
646
647 nonseekable_open(inode, filp);
648
649 /* find a device that is not in use. */
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100650 index = devpts_new_index(inode);
Alan Coxd81ed102008-10-13 10:41:42 +0100651 if (index < 0)
652 return index;
653
654 mutex_lock(&tty_mutex);
Alan Cox73ec06f2008-10-13 10:42:29 +0100655 tty = tty_init_dev(ptm_driver, index, 1);
Alan Coxd81ed102008-10-13 10:41:42 +0100656 mutex_unlock(&tty_mutex);
657
Alan Cox73ec06f2008-10-13 10:42:29 +0100658 if (IS_ERR(tty)) {
659 retval = PTR_ERR(tty);
Alan Coxd81ed102008-10-13 10:41:42 +0100660 goto out;
Alan Cox73ec06f2008-10-13 10:42:29 +0100661 }
Alan Coxd81ed102008-10-13 10:41:42 +0100662
663 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
664 filp->private_data = tty;
665 file_move(filp, &tty->tty_files);
666
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100667 retval = devpts_pty_new(inode, tty->link);
Alan Coxd81ed102008-10-13 10:41:42 +0100668 if (retval)
669 goto out1;
670
671 retval = ptm_driver->ops->open(tty, filp);
672 if (!retval)
673 return 0;
674out1:
675 tty_release_dev(filp);
676 return retval;
677out:
Sukadev Bhattiprolu15f1a632008-10-13 10:42:59 +0100678 devpts_kill_index(inode, index);
Alan Coxd81ed102008-10-13 10:41:42 +0100679 return retval;
680}
681
682static int ptmx_open(struct inode *inode, struct file *filp)
683{
684 int ret;
685
686 lock_kernel();
687 ret = __ptmx_open(inode, filp);
688 unlock_kernel();
689 return ret;
690}
691
692static struct file_operations ptmx_fops;
693
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694static void __init unix98_pty_init(void)
695{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 ptm_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
697 if (!ptm_driver)
698 panic("Couldn't allocate Unix98 ptm driver");
699 pts_driver = alloc_tty_driver(NR_UNIX98_PTY_MAX);
700 if (!pts_driver)
701 panic("Couldn't allocate Unix98 pts driver");
702
703 ptm_driver->owner = THIS_MODULE;
704 ptm_driver->driver_name = "pty_master";
705 ptm_driver->name = "ptm";
706 ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
707 ptm_driver->minor_start = 0;
708 ptm_driver->type = TTY_DRIVER_TYPE_PTY;
709 ptm_driver->subtype = PTY_TYPE_MASTER;
710 ptm_driver->init_termios = tty_std_termios;
711 ptm_driver->init_termios.c_iflag = 0;
712 ptm_driver->init_termios.c_oflag = 0;
713 ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
714 ptm_driver->init_termios.c_lflag = 0;
Alan Cox606d0992006-12-08 02:38:45 -0800715 ptm_driver->init_termios.c_ispeed = 38400;
716 ptm_driver->init_termios.c_ospeed = 38400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
Greg Kroah-Hartman331b8312005-06-20 21:15:16 -0700718 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 ptm_driver->other = pts_driver;
Alan Coxfeebed62008-10-13 10:41:30 +0100720 tty_set_operations(ptm_driver, &ptm_unix98_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721
722 pts_driver->owner = THIS_MODULE;
723 pts_driver->driver_name = "pty_slave";
724 pts_driver->name = "pts";
725 pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
726 pts_driver->minor_start = 0;
727 pts_driver->type = TTY_DRIVER_TYPE_PTY;
728 pts_driver->subtype = PTY_TYPE_SLAVE;
729 pts_driver->init_termios = tty_std_termios;
730 pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
Alan Cox606d0992006-12-08 02:38:45 -0800731 pts_driver->init_termios.c_ispeed = 38400;
732 pts_driver->init_termios.c_ospeed = 38400;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |
Greg Kroah-Hartman331b8312005-06-20 21:15:16 -0700734 TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 pts_driver->other = ptm_driver;
Alan Cox99f1fe12008-10-13 10:42:00 +0100736 tty_set_operations(pts_driver, &pty_unix98_ops);
Alan Coxfe9cd962008-10-13 10:43:38 +0100737
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 if (tty_register_driver(ptm_driver))
739 panic("Couldn't register Unix98 ptm driver");
740 if (tty_register_driver(pts_driver))
741 panic("Couldn't register Unix98 pts driver");
742
Alan Coxfe9cd962008-10-13 10:43:38 +0100743 register_sysctl_table(pty_root_table);
Alan Coxd81ed102008-10-13 10:41:42 +0100744
745 /* Now create the /dev/ptmx special device */
746 tty_default_fops(&ptmx_fops);
747 ptmx_fops.open = ptmx_open;
748
749 cdev_init(&ptmx_cdev, &ptmx_fops);
750 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
751 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
752 panic("Couldn't register /dev/ptmx driver\n");
753 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754}
Alan Coxd81ed102008-10-13 10:41:42 +0100755
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756#else
757static inline void unix98_pty_init(void) { }
758#endif
759
760static int __init pty_init(void)
761{
762 legacy_pty_init();
763 unix98_pty_init();
764 return 0;
765}
766module_init(pty_init);