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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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 | |
1da177e4 | 8 | * |
fe9cd962 AC |
9 | * 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. | |
1da177e4 LT |
12 | */ |
13 | ||
fe9cd962 | 14 | #include <linux/module.h> |
1da177e4 LT |
15 | |
16 | #include <linux/errno.h> | |
1da177e4 LT |
17 | #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> | |
1da177e4 | 25 | #include <linux/sysctl.h> |
d81ed103 | 26 | #include <linux/device.h> |
fe9cd962 | 27 | #include <linux/uaccess.h> |
1da177e4 LT |
28 | #include <linux/bitops.h> |
29 | #include <linux/devpts_fs.h> | |
30 | ||
fe9cd962 AC |
31 | #include <asm/system.h> |
32 | ||
1da177e4 LT |
33 | /* These are global because they are accessed in tty_io.c */ |
34 | #ifdef CONFIG_UNIX98_PTYS | |
da2bdf9a | 35 | static struct tty_driver *ptm_driver; |
1da177e4 LT |
36 | static struct tty_driver *pts_driver; |
37 | #endif | |
38 | ||
fe9cd962 | 39 | static void pty_close(struct tty_struct *tty, struct file *filp) |
1da177e4 | 40 | { |
fe9cd962 AC |
41 | BUG_ON(!tty); |
42 | if (tty->driver->subtype == PTY_TYPE_MASTER) | |
43 | WARN_ON(tty->count > 1); | |
44 | else { | |
1da177e4 LT |
45 | 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) | |
15f1a633 | 61 | devpts_pty_kill(tty->link); |
1da177e4 LT |
62 | #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 | |
fe9cd962 | 71 | * unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE |
1da177e4 LT |
72 | * 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 | */ | |
fe9cd962 | 77 | static void pty_unthrottle(struct tty_struct *tty) |
1da177e4 LT |
78 | { |
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 | /* | |
fe9cd962 | 89 | * WSH 05/24/97: modified to |
1da177e4 LT |
90 | * (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 | |
817d6d3b | 100 | * risking deadlocks. |
1da177e4 | 101 | */ |
fe9cd962 AC |
102 | static int pty_write(struct tty_struct *tty, const unsigned char *buf, |
103 | int count) | |
1da177e4 LT |
104 | { |
105 | struct tty_struct *to = tty->link; | |
106 | int c; | |
107 | ||
108 | if (!to || tty->stopped) | |
109 | return 0; | |
110 | ||
33f0f88f | 111 | c = to->receive_room; |
1da177e4 LT |
112 | if (c > count) |
113 | c = count; | |
a352def2 | 114 | to->ldisc.ops->receive_buf(to, buf, NULL, c); |
fe9cd962 | 115 | |
1da177e4 LT |
116 | return c; |
117 | } | |
118 | ||
119 | static 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 | ||
33f0f88f | 126 | return to->receive_room; |
1da177e4 LT |
127 | } |
128 | ||
129 | /* | |
130 | * WSH 05/24/97: Modified for asymmetric MASTER/SLAVE behavior | |
fe9cd962 | 131 | * The chars_in_buffer() value is used by the ldisc select() function |
1da177e4 LT |
132 | * 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 > | |
fe9cd962 AC |
138 | * 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 | |
1da177e4 | 140 | * read. (The N_TTY ldisc.chars_in_buffer now knows this.) |
fe9cd962 | 141 | * |
1da177e4 LT |
142 | * 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 | */ | |
146 | static int pty_chars_in_buffer(struct tty_struct *tty) | |
147 | { | |
148 | struct tty_struct *to = tty->link; | |
1da177e4 LT |
149 | int count; |
150 | ||
151 | /* We should get the line discipline lock for "tty->link" */ | |
a352def2 | 152 | if (!to || !to->ldisc.ops->chars_in_buffer) |
1da177e4 LT |
153 | return 0; |
154 | ||
155 | /* The ldisc must report 0 if no characters available to be read */ | |
a352def2 | 156 | count = to->ldisc.ops->chars_in_buffer(to); |
1da177e4 | 157 | |
fe9cd962 AC |
158 | if (tty->driver->subtype == PTY_TYPE_SLAVE) |
159 | return count; | |
1da177e4 | 160 | |
fe9cd962 | 161 | /* Master side driver ... if the other side's read buffer is less than |
1da177e4 | 162 | * half full, return 0 to allow writers to proceed; otherwise return |
fe9cd962 | 163 | * the count. This leaves a comfortable margin to avoid overflow, |
1da177e4 LT |
164 | * and still allows half a buffer's worth of typed-ahead commands. |
165 | */ | |
fe9cd962 | 166 | return (count < N_TTY_BUF_SIZE/2) ? 0 : count; |
1da177e4 LT |
167 | } |
168 | ||
169 | /* Set the lock flag on a pty */ | |
fe9cd962 | 170 | static int pty_set_lock(struct tty_struct *tty, int __user *arg) |
1da177e4 LT |
171 | { |
172 | int val; | |
fe9cd962 | 173 | if (get_user(val, arg)) |
1da177e4 LT |
174 | 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 | ||
182 | static void pty_flush_buffer(struct tty_struct *tty) | |
183 | { | |
184 | struct tty_struct *to = tty->link; | |
04f378b1 | 185 | unsigned long flags; |
fe9cd962 | 186 | |
1da177e4 LT |
187 | if (!to) |
188 | return; | |
fe9cd962 | 189 | |
a352def2 AC |
190 | if (to->ldisc.ops->flush_buffer) |
191 | to->ldisc.ops->flush_buffer(to); | |
fe9cd962 | 192 | |
1da177e4 | 193 | if (to->packet) { |
04f378b1 | 194 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 LT |
195 | tty->ctrl_status |= TIOCPKT_FLUSHWRITE; |
196 | wake_up_interruptible(&to->read_wait); | |
04f378b1 | 197 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
198 | } |
199 | } | |
200 | ||
fe9cd962 | 201 | static int pty_open(struct tty_struct *tty, struct file *filp) |
1da177e4 LT |
202 | { |
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); | |
1da177e4 LT |
218 | retval = 0; |
219 | out: | |
220 | return retval; | |
221 | } | |
222 | ||
fe9cd962 AC |
223 | static void pty_set_termios(struct tty_struct *tty, |
224 | struct ktermios *old_termios) | |
1da177e4 | 225 | { |
fe9cd962 AC |
226 | tty->termios->c_cflag &= ~(CSIZE | PARENB); |
227 | tty->termios->c_cflag |= (CS8 | CREAD); | |
1da177e4 LT |
228 | } |
229 | ||
fc6f6238 AC |
230 | /** |
231 | * pty_do_resize - resize event | |
232 | * @tty: tty being resized | |
c774bda2 | 233 | * @ws: window size being set. |
fc6f6238 AC |
234 | * |
235 | * Update the termios variables and send the neccessary signals to | |
236 | * peform a terminal resize correctly | |
237 | */ | |
238 | ||
239 | int 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 */ | |
272 | done: | |
273 | mutex_unlock(&tty->termios_mutex); | |
274 | return 0; | |
275 | } | |
276 | ||
bf970ee4 AC |
277 | static 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 | } | |
fe9cd962 | 304 | |
bf970ee4 AC |
305 | /* |
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; | |
320 | free_mem_out: | |
321 | module_put(o_tty->driver->owner); | |
322 | free_tty_struct(o_tty); | |
323 | return -ENOMEM; | |
324 | } | |
325 | ||
326 | ||
b68e31d0 | 327 | static const struct tty_operations pty_ops = { |
bf970ee4 | 328 | .install = pty_install, |
1da177e4 LT |
329 | .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, | |
fc6f6238 | 337 | .resize = pty_resize |
1da177e4 LT |
338 | }; |
339 | ||
340 | /* Traditional BSD devices */ | |
341 | #ifdef CONFIG_LEGACY_PTYS | |
342 | static struct tty_driver *pty_driver, *pty_slave_driver; | |
343 | ||
344 | static 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 | ||
dc8c8587 KS |
354 | static int legacy_count = CONFIG_LEGACY_PTY_COUNT; |
355 | module_param(legacy_count, int, 0); | |
356 | ||
3e8e88ca AC |
357 | static 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, | |
fc6f6238 | 367 | .resize = pty_resize |
3e8e88ca AC |
368 | }; |
369 | ||
1da177e4 LT |
370 | static void __init legacy_pty_init(void) |
371 | { | |
dc8c8587 KS |
372 | if (legacy_count <= 0) |
373 | return; | |
1da177e4 | 374 | |
dc8c8587 | 375 | pty_driver = alloc_tty_driver(legacy_count); |
1da177e4 LT |
376 | if (!pty_driver) |
377 | panic("Couldn't allocate pty driver"); | |
378 | ||
dc8c8587 | 379 | pty_slave_driver = alloc_tty_driver(legacy_count); |
1da177e4 LT |
380 | 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"; | |
1da177e4 LT |
386 | 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; | |
606d099c AC |
395 | pty_driver->init_termios.c_ispeed = 38400; |
396 | pty_driver->init_termios.c_ospeed = 38400; | |
1da177e4 LT |
397 | 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); | |
1da177e4 LT |
400 | |
401 | pty_slave_driver->owner = THIS_MODULE; | |
402 | pty_slave_driver->driver_name = "pty_slave"; | |
403 | pty_slave_driver->name = "ttyp"; | |
1da177e4 LT |
404 | 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; | |
606d099c AC |
410 | pty_slave_driver->init_termios.c_ispeed = 38400; |
411 | pty_slave_driver->init_termios.c_ospeed = 38400; | |
1da177e4 LT |
412 | 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 | |
423 | static 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 | */ | |
432 | int pty_limit = NR_UNIX98_PTY_DEFAULT; | |
fe9cd962 | 433 | static int pty_limit_min; |
1da177e4 | 434 | static int pty_limit_max = NR_UNIX98_PTY_MAX; |
fe9cd962 | 435 | static int pty_count; |
1da177e4 | 436 | |
d81ed103 AC |
437 | static struct cdev ptmx_cdev; |
438 | ||
35834ca1 | 439 | static struct ctl_table pty_table[] = { |
1da177e4 LT |
440 | { |
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, | |
bf970ee4 | 455 | .data = &pty_count, |
1da177e4 LT |
456 | .proc_handler = &proc_dointvec, |
457 | }, { | |
458 | .ctl_name = 0 | |
459 | } | |
460 | }; | |
461 | ||
35834ca1 EB |
462 | static 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 | ||
472 | static 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 | ||
1da177e4 LT |
483 | static 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 | ||
99f1fe18 AC |
496 | /** |
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 | ||
15f1a633 SB |
505 | static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, |
506 | struct inode *ptm_inode, int idx) | |
99f1fe18 | 507 | { |
15f1a633 | 508 | struct tty_struct *tty = devpts_get_tty(ptm_inode, idx); |
99f1fe18 AC |
509 | 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 | ||
15f1a633 SB |
523 | static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver, |
524 | struct inode *pts_inode, int idx) | |
99f1fe18 | 525 | { |
15f1a633 | 526 | struct tty_struct *tty = devpts_get_tty(pts_inode, idx); |
99f1fe18 AC |
527 | /* Master must be open before slave */ |
528 | if (!tty) | |
529 | return ERR_PTR(-EIO); | |
530 | return tty; | |
531 | } | |
532 | ||
bf970ee4 | 533 | static void pty_unix98_shutdown(struct tty_struct *tty) |
feebed65 AC |
534 | { |
535 | /* We have our own method as we don't use the tty index */ | |
536 | kfree(tty->termios); | |
feebed65 AC |
537 | } |
538 | ||
8b0a88d5 AC |
539 | /* We have no need to install and remove our tty objects as devpts does all |
540 | the work for us */ | |
541 | ||
bf970ee4 | 542 | static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty) |
8b0a88d5 | 543 | { |
bf970ee4 AC |
544 | 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 | ||
8dff04ea | 557 | tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL); |
bf970ee4 AC |
558 | if (tty->termios == NULL) |
559 | goto free_mem_out; | |
560 | *tty->termios = driver->init_termios; | |
8dff04ea AC |
561 | tty->termios_locked = tty->termios + 1; |
562 | ||
563 | o_tty->termios = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL); | |
bf970ee4 AC |
564 | if (o_tty->termios == NULL) |
565 | goto free_mem_out; | |
566 | *o_tty->termios = driver->other->init_termios; | |
8dff04ea | 567 | o_tty->termios_locked = o_tty->termios + 1; |
bf970ee4 AC |
568 | |
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++; | |
8b0a88d5 | 583 | return 0; |
bf970ee4 | 584 | free_mem_out: |
8dff04ea | 585 | kfree(o_tty->termios); |
bf970ee4 AC |
586 | module_put(o_tty->driver->owner); |
587 | free_tty_struct(o_tty); | |
8dff04ea | 588 | kfree(tty->termios); |
bf970ee4 | 589 | return -ENOMEM; |
8b0a88d5 AC |
590 | } |
591 | ||
bf970ee4 | 592 | static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty) |
8b0a88d5 | 593 | { |
bf970ee4 | 594 | pty_count--; |
8b0a88d5 AC |
595 | } |
596 | ||
feebed65 | 597 | static const struct tty_operations ptm_unix98_ops = { |
99f1fe18 | 598 | .lookup = ptm_unix98_lookup, |
bf970ee4 AC |
599 | .install = pty_unix98_install, |
600 | .remove = pty_unix98_remove, | |
3e8e88ca AC |
601 | .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, | |
feebed65 | 609 | .ioctl = pty_unix98_ioctl, |
fc6f6238 AC |
610 | .shutdown = pty_unix98_shutdown, |
611 | .resize = pty_resize | |
3e8e88ca AC |
612 | }; |
613 | ||
99f1fe18 AC |
614 | static const struct tty_operations pty_unix98_ops = { |
615 | .lookup = pts_unix98_lookup, | |
bf970ee4 AC |
616 | .install = pty_unix98_install, |
617 | .remove = pty_unix98_remove, | |
99f1fe18 AC |
618 | .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, | |
bf970ee4 | 626 | .shutdown = pty_unix98_shutdown |
99f1fe18 | 627 | }; |
d81ed103 AC |
628 | |
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 | ||
641 | static 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. */ | |
15f1a633 | 650 | index = devpts_new_index(inode); |
d81ed103 AC |
651 | if (index < 0) |
652 | return index; | |
653 | ||
654 | mutex_lock(&tty_mutex); | |
73ec06fc | 655 | tty = tty_init_dev(ptm_driver, index, 1); |
d81ed103 AC |
656 | mutex_unlock(&tty_mutex); |
657 | ||
73ec06fc AC |
658 | if (IS_ERR(tty)) { |
659 | retval = PTR_ERR(tty); | |
d81ed103 | 660 | goto out; |
73ec06fc | 661 | } |
d81ed103 AC |
662 | |
663 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
664 | filp->private_data = tty; | |
665 | file_move(filp, &tty->tty_files); | |
666 | ||
15f1a633 | 667 | retval = devpts_pty_new(inode, tty->link); |
d81ed103 AC |
668 | if (retval) |
669 | goto out1; | |
670 | ||
671 | retval = ptm_driver->ops->open(tty, filp); | |
672 | if (!retval) | |
673 | return 0; | |
674 | out1: | |
675 | tty_release_dev(filp); | |
676 | return retval; | |
677 | out: | |
15f1a633 | 678 | devpts_kill_index(inode, index); |
d81ed103 AC |
679 | return retval; |
680 | } | |
681 | ||
682 | static 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 | ||
692 | static struct file_operations ptmx_fops; | |
693 | ||
1da177e4 LT |
694 | static void __init unix98_pty_init(void) |
695 | { | |
1da177e4 LT |
696 | 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; | |
606d099c AC |
715 | ptm_driver->init_termios.c_ispeed = 38400; |
716 | ptm_driver->init_termios.c_ospeed = 38400; | |
1da177e4 | 717 | ptm_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | |
331b8319 | 718 | TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; |
1da177e4 | 719 | ptm_driver->other = pts_driver; |
feebed65 | 720 | tty_set_operations(ptm_driver, &ptm_unix98_ops); |
1da177e4 LT |
721 | |
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; | |
606d099c AC |
731 | pts_driver->init_termios.c_ispeed = 38400; |
732 | pts_driver->init_termios.c_ospeed = 38400; | |
1da177e4 | 733 | pts_driver->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | |
331b8319 | 734 | TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_DEVPTS_MEM; |
1da177e4 | 735 | pts_driver->other = ptm_driver; |
99f1fe18 | 736 | tty_set_operations(pts_driver, &pty_unix98_ops); |
fe9cd962 | 737 | |
1da177e4 LT |
738 | 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 | ||
fe9cd962 | 743 | register_sysctl_table(pty_root_table); |
d81ed103 AC |
744 | |
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"); | |
1da177e4 | 754 | } |
d81ed103 | 755 | |
1da177e4 LT |
756 | #else |
757 | static inline void unix98_pty_init(void) { } | |
758 | #endif | |
759 | ||
760 | static int __init pty_init(void) | |
761 | { | |
762 | legacy_pty_init(); | |
763 | unix98_pty_init(); | |
764 | return 0; | |
765 | } | |
766 | module_init(pty_init); |