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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 */
5
6/*
7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
8 * or rs-channels. It also implements echoing, cooked mode etc.
9 *
10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 *
12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
13 * tty_struct and tty_queue structures. Previously there was an array
14 * of 256 tty_struct's which was statically allocated, and the
15 * tty_queue structures were allocated at boot time. Both are now
16 * dynamically allocated only when the tty is open.
17 *
18 * Also restructured routines so that there is more of a separation
19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
20 * the low-level tty routines (serial.c, pty.c, console.c). This
21 * makes for cleaner and more compact code. -TYT, 9/17/92
22 *
23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
24 * which can be dynamically activated and de-activated by the line
25 * discipline handling modules (like SLIP).
26 *
27 * NOTE: pay no attention to the line discipline code (yet); its
28 * interface is still subject to change in this version...
29 * -- TYT, 1/31/92
30 *
31 * Added functionality to the OPOST tty handling. No delays, but all
32 * other bits should be there.
33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 *
35 * Rewrote canonical mode and added more termios flags.
36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 *
38 * Reorganized FASYNC support so mouse code can share it.
39 * -- ctm@ardi.com, 9Sep95
40 *
41 * New TIOCLINUX variants added.
42 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 *
44 * Restrict vt switching via ioctl()
45 * -- grif@cs.ucr.edu, 5-Dec-95
46 *
47 * Move console and virtual terminal code to more appropriate files,
48 * implement CONFIG_VT and generalize console device interface.
49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 *
51 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
52 * -- Bill Hawes <whawes@star.net>, June 97
53 *
54 * Added devfs support.
55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 *
57 * Added support for a Unix98-style ptmx device.
58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 *
60 * Reduced memory usage for older ARM systems
61 * -- Russell King <rmk@arm.linux.org.uk>
62 *
63 * Move do_SAK() into process context. Less stack use in devfs functions.
64 * alloc_tty_struct() always uses kmalloc()
65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
66 */
67
68#include <linux/types.h>
69#include <linux/major.h>
70#include <linux/errno.h>
71#include <linux/signal.h>
72#include <linux/fcntl.h>
73#include <linux/sched/signal.h>
74#include <linux/sched/task.h>
75#include <linux/interrupt.h>
76#include <linux/tty.h>
77#include <linux/tty_driver.h>
78#include <linux/tty_flip.h>
79#include <linux/devpts_fs.h>
80#include <linux/file.h>
81#include <linux/fdtable.h>
82#include <linux/console.h>
83#include <linux/timer.h>
84#include <linux/ctype.h>
85#include <linux/kd.h>
86#include <linux/mm.h>
87#include <linux/string.h>
88#include <linux/slab.h>
89#include <linux/poll.h>
90#include <linux/ppp-ioctl.h>
91#include <linux/proc_fs.h>
92#include <linux/init.h>
93#include <linux/module.h>
94#include <linux/device.h>
95#include <linux/wait.h>
96#include <linux/bitops.h>
97#include <linux/delay.h>
98#include <linux/seq_file.h>
99#include <linux/serial.h>
100#include <linux/ratelimit.h>
101#include <linux/compat.h>
102#include <linux/uaccess.h>
103#include <linux/termios_internal.h>
104#include <linux/fs.h>
105
106#include <linux/kbd_kern.h>
107#include <linux/vt_kern.h>
108#include <linux/selection.h>
109
110#include <linux/kmod.h>
111#include <linux/nsproxy.h>
112#include "tty.h"
113
114#undef TTY_DEBUG_HANGUP
115#ifdef TTY_DEBUG_HANGUP
116# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
117#else
118# define tty_debug_hangup(tty, f, args...) do { } while (0)
119#endif
120
121#define TTY_PARANOIA_CHECK 1
122#define CHECK_TTY_COUNT 1
123
124struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
125 .c_iflag = ICRNL | IXON,
126 .c_oflag = OPOST | ONLCR,
127 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
128 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
129 ECHOCTL | ECHOKE | IEXTEN,
130 .c_cc = INIT_C_CC,
131 .c_ispeed = 38400,
132 .c_ospeed = 38400,
133 /* .c_line = N_TTY, */
134};
135EXPORT_SYMBOL(tty_std_termios);
136
137/* This list gets poked at by procfs and various bits of boot up code. This
138 * could do with some rationalisation such as pulling the tty proc function
139 * into this file.
140 */
141
142LIST_HEAD(tty_drivers); /* linked list of tty drivers */
143
144/* Mutex to protect creating and releasing a tty */
145DEFINE_MUTEX(tty_mutex);
146
147static ssize_t tty_read(struct kiocb *, struct iov_iter *);
148static ssize_t tty_write(struct kiocb *, struct iov_iter *);
149static __poll_t tty_poll(struct file *, poll_table *);
150static int tty_open(struct inode *, struct file *);
151#ifdef CONFIG_COMPAT
152static long tty_compat_ioctl(struct file *file, unsigned int cmd,
153 unsigned long arg);
154#else
155#define tty_compat_ioctl NULL
156#endif
157static int __tty_fasync(int fd, struct file *filp, int on);
158static int tty_fasync(int fd, struct file *filp, int on);
159static void release_tty(struct tty_struct *tty, int idx);
160
161/**
162 * free_tty_struct - free a disused tty
163 * @tty: tty struct to free
164 *
165 * Free the write buffers, tty queue and tty memory itself.
166 *
167 * Locking: none. Must be called after tty is definitely unused
168 */
169static void free_tty_struct(struct tty_struct *tty)
170{
171 tty_ldisc_deinit(tty);
172 put_device(tty->dev);
173 kvfree(tty->write_buf);
174 kfree(tty);
175}
176
177static inline struct tty_struct *file_tty(struct file *file)
178{
179 return ((struct tty_file_private *)file->private_data)->tty;
180}
181
182int tty_alloc_file(struct file *file)
183{
184 struct tty_file_private *priv;
185
186 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
187 if (!priv)
188 return -ENOMEM;
189
190 file->private_data = priv;
191
192 return 0;
193}
194
195/* Associate a new file with the tty structure */
196void tty_add_file(struct tty_struct *tty, struct file *file)
197{
198 struct tty_file_private *priv = file->private_data;
199
200 priv->tty = tty;
201 priv->file = file;
202
203 spin_lock(&tty->files_lock);
204 list_add(&priv->list, &tty->tty_files);
205 spin_unlock(&tty->files_lock);
206}
207
208/**
209 * tty_free_file - free file->private_data
210 * @file: to free private_data of
211 *
212 * This shall be used only for fail path handling when tty_add_file was not
213 * called yet.
214 */
215void tty_free_file(struct file *file)
216{
217 struct tty_file_private *priv = file->private_data;
218
219 file->private_data = NULL;
220 kfree(priv);
221}
222
223/* Delete file from its tty */
224static void tty_del_file(struct file *file)
225{
226 struct tty_file_private *priv = file->private_data;
227 struct tty_struct *tty = priv->tty;
228
229 spin_lock(&tty->files_lock);
230 list_del(&priv->list);
231 spin_unlock(&tty->files_lock);
232 tty_free_file(file);
233}
234
235/**
236 * tty_name - return tty naming
237 * @tty: tty structure
238 *
239 * Convert a tty structure into a name. The name reflects the kernel naming
240 * policy and if udev is in use may not reflect user space
241 *
242 * Locking: none
243 */
244const char *tty_name(const struct tty_struct *tty)
245{
246 if (!tty) /* Hmm. NULL pointer. That's fun. */
247 return "NULL tty";
248 return tty->name;
249}
250EXPORT_SYMBOL(tty_name);
251
252const char *tty_driver_name(const struct tty_struct *tty)
253{
254 if (!tty || !tty->driver)
255 return "";
256 return tty->driver->name;
257}
258
259static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
260 const char *routine)
261{
262#ifdef TTY_PARANOIA_CHECK
263 if (!tty) {
264 pr_warn("(%d:%d): %s: NULL tty\n",
265 imajor(inode), iminor(inode), routine);
266 return 1;
267 }
268#endif
269 return 0;
270}
271
272/* Caller must hold tty_lock */
273static void check_tty_count(struct tty_struct *tty, const char *routine)
274{
275#ifdef CHECK_TTY_COUNT
276 struct list_head *p;
277 int count = 0, kopen_count = 0;
278
279 spin_lock(&tty->files_lock);
280 list_for_each(p, &tty->tty_files) {
281 count++;
282 }
283 spin_unlock(&tty->files_lock);
284 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
285 tty->driver->subtype == PTY_TYPE_SLAVE &&
286 tty->link && tty->link->count)
287 count++;
288 if (tty_port_kopened(tty->port))
289 kopen_count++;
290 if (tty->count != (count + kopen_count)) {
291 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
292 routine, tty->count, count, kopen_count);
293 }
294#endif
295}
296
297/**
298 * get_tty_driver - find device of a tty
299 * @device: device identifier
300 * @index: returns the index of the tty
301 *
302 * This routine returns a tty driver structure, given a device number and also
303 * passes back the index number.
304 *
305 * Locking: caller must hold tty_mutex
306 */
307static struct tty_driver *get_tty_driver(dev_t device, int *index)
308{
309 struct tty_driver *p;
310
311 list_for_each_entry(p, &tty_drivers, tty_drivers) {
312 dev_t base = MKDEV(p->major, p->minor_start);
313
314 if (device < base || device >= base + p->num)
315 continue;
316 *index = device - base;
317 return tty_driver_kref_get(p);
318 }
319 return NULL;
320}
321
322/**
323 * tty_dev_name_to_number - return dev_t for device name
324 * @name: user space name of device under /dev
325 * @number: pointer to dev_t that this function will populate
326 *
327 * This function converts device names like ttyS0 or ttyUSB1 into dev_t like
328 * (4, 64) or (188, 1). If no corresponding driver is registered then the
329 * function returns -%ENODEV.
330 *
331 * Locking: this acquires tty_mutex to protect the tty_drivers list from
332 * being modified while we are traversing it, and makes sure to
333 * release it before exiting.
334 */
335int tty_dev_name_to_number(const char *name, dev_t *number)
336{
337 struct tty_driver *p;
338 int ret;
339 int index, prefix_length = 0;
340 const char *str;
341
342 for (str = name; *str && !isdigit(*str); str++)
343 ;
344
345 if (!*str)
346 return -EINVAL;
347
348 ret = kstrtoint(str, 10, &index);
349 if (ret)
350 return ret;
351
352 prefix_length = str - name;
353 mutex_lock(&tty_mutex);
354
355 list_for_each_entry(p, &tty_drivers, tty_drivers)
356 if (prefix_length == strlen(p->name) && strncmp(name,
357 p->name, prefix_length) == 0) {
358 if (index < p->num) {
359 *number = MKDEV(p->major, p->minor_start + index);
360 goto out;
361 }
362 }
363
364 /* if here then driver wasn't found */
365 ret = -ENODEV;
366out:
367 mutex_unlock(&tty_mutex);
368 return ret;
369}
370EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
371
372#ifdef CONFIG_CONSOLE_POLL
373
374/**
375 * tty_find_polling_driver - find device of a polled tty
376 * @name: name string to match
377 * @line: pointer to resulting tty line nr
378 *
379 * This routine returns a tty driver structure, given a name and the condition
380 * that the tty driver is capable of polled operation.
381 */
382struct tty_driver *tty_find_polling_driver(char *name, int *line)
383{
384 struct tty_driver *p, *res = NULL;
385 int tty_line = 0;
386 int len;
387 char *str, *stp;
388
389 for (str = name; *str; str++)
390 if ((*str >= '0' && *str <= '9') || *str == ',')
391 break;
392 if (!*str)
393 return NULL;
394
395 len = str - name;
396 tty_line = simple_strtoul(str, &str, 10);
397
398 mutex_lock(&tty_mutex);
399 /* Search through the tty devices to look for a match */
400 list_for_each_entry(p, &tty_drivers, tty_drivers) {
401 if (!len || strncmp(name, p->name, len) != 0)
402 continue;
403 stp = str;
404 if (*stp == ',')
405 stp++;
406 if (*stp == '\0')
407 stp = NULL;
408
409 if (tty_line >= 0 && tty_line < p->num && p->ops &&
410 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
411 res = tty_driver_kref_get(p);
412 *line = tty_line;
413 break;
414 }
415 }
416 mutex_unlock(&tty_mutex);
417
418 return res;
419}
420EXPORT_SYMBOL_GPL(tty_find_polling_driver);
421#endif
422
423static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to)
424{
425 return 0;
426}
427
428static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
429{
430 return -EIO;
431}
432
433/* No kernel lock held - none needed ;) */
434static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
435{
436 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
437}
438
439static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
440 unsigned long arg)
441{
442 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
443}
444
445static long hung_up_tty_compat_ioctl(struct file *file,
446 unsigned int cmd, unsigned long arg)
447{
448 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
449}
450
451static int hung_up_tty_fasync(int fd, struct file *file, int on)
452{
453 return -ENOTTY;
454}
455
456static void tty_show_fdinfo(struct seq_file *m, struct file *file)
457{
458 struct tty_struct *tty = file_tty(file);
459
460 if (tty && tty->ops && tty->ops->show_fdinfo)
461 tty->ops->show_fdinfo(tty, m);
462}
463
464static const struct file_operations tty_fops = {
465 .llseek = no_llseek,
466 .read_iter = tty_read,
467 .write_iter = tty_write,
468 .splice_read = copy_splice_read,
469 .splice_write = iter_file_splice_write,
470 .poll = tty_poll,
471 .unlocked_ioctl = tty_ioctl,
472 .compat_ioctl = tty_compat_ioctl,
473 .open = tty_open,
474 .release = tty_release,
475 .fasync = tty_fasync,
476 .show_fdinfo = tty_show_fdinfo,
477};
478
479static const struct file_operations console_fops = {
480 .llseek = no_llseek,
481 .read_iter = tty_read,
482 .write_iter = redirected_tty_write,
483 .splice_read = copy_splice_read,
484 .splice_write = iter_file_splice_write,
485 .poll = tty_poll,
486 .unlocked_ioctl = tty_ioctl,
487 .compat_ioctl = tty_compat_ioctl,
488 .open = tty_open,
489 .release = tty_release,
490 .fasync = tty_fasync,
491};
492
493static const struct file_operations hung_up_tty_fops = {
494 .llseek = no_llseek,
495 .read_iter = hung_up_tty_read,
496 .write_iter = hung_up_tty_write,
497 .poll = hung_up_tty_poll,
498 .unlocked_ioctl = hung_up_tty_ioctl,
499 .compat_ioctl = hung_up_tty_compat_ioctl,
500 .release = tty_release,
501 .fasync = hung_up_tty_fasync,
502};
503
504static DEFINE_SPINLOCK(redirect_lock);
505static struct file *redirect;
506
507/**
508 * tty_wakeup - request more data
509 * @tty: terminal
510 *
511 * Internal and external helper for wakeups of tty. This function informs the
512 * line discipline if present that the driver is ready to receive more output
513 * data.
514 */
515void tty_wakeup(struct tty_struct *tty)
516{
517 struct tty_ldisc *ld;
518
519 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
520 ld = tty_ldisc_ref(tty);
521 if (ld) {
522 if (ld->ops->write_wakeup)
523 ld->ops->write_wakeup(tty);
524 tty_ldisc_deref(ld);
525 }
526 }
527 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
528}
529EXPORT_SYMBOL_GPL(tty_wakeup);
530
531/**
532 * tty_release_redirect - Release a redirect on a pty if present
533 * @tty: tty device
534 *
535 * This is available to the pty code so if the master closes, if the slave is a
536 * redirect it can release the redirect.
537 */
538static struct file *tty_release_redirect(struct tty_struct *tty)
539{
540 struct file *f = NULL;
541
542 spin_lock(&redirect_lock);
543 if (redirect && file_tty(redirect) == tty) {
544 f = redirect;
545 redirect = NULL;
546 }
547 spin_unlock(&redirect_lock);
548
549 return f;
550}
551
552/**
553 * __tty_hangup - actual handler for hangup events
554 * @tty: tty device
555 * @exit_session: if non-zero, signal all foreground group processes
556 *
557 * This can be called by a "kworker" kernel thread. That is process synchronous
558 * but doesn't hold any locks, so we need to make sure we have the appropriate
559 * locks for what we're doing.
560 *
561 * The hangup event clears any pending redirections onto the hung up device. It
562 * ensures future writes will error and it does the needed line discipline
563 * hangup and signal delivery. The tty object itself remains intact.
564 *
565 * Locking:
566 * * BTM
567 *
568 * * redirect lock for undoing redirection
569 * * file list lock for manipulating list of ttys
570 * * tty_ldiscs_lock from called functions
571 * * termios_rwsem resetting termios data
572 * * tasklist_lock to walk task list for hangup event
573 *
574 * * ->siglock to protect ->signal/->sighand
575 *
576 */
577static void __tty_hangup(struct tty_struct *tty, int exit_session)
578{
579 struct file *cons_filp = NULL;
580 struct file *filp, *f;
581 struct tty_file_private *priv;
582 int closecount = 0, n;
583 int refs;
584
585 if (!tty)
586 return;
587
588 f = tty_release_redirect(tty);
589
590 tty_lock(tty);
591
592 if (test_bit(TTY_HUPPED, &tty->flags)) {
593 tty_unlock(tty);
594 return;
595 }
596
597 /*
598 * Some console devices aren't actually hung up for technical and
599 * historical reasons, which can lead to indefinite interruptible
600 * sleep in n_tty_read(). The following explicitly tells
601 * n_tty_read() to abort readers.
602 */
603 set_bit(TTY_HUPPING, &tty->flags);
604
605 /* inuse_filps is protected by the single tty lock,
606 * this really needs to change if we want to flush the
607 * workqueue with the lock held.
608 */
609 check_tty_count(tty, "tty_hangup");
610
611 spin_lock(&tty->files_lock);
612 /* This breaks for file handles being sent over AF_UNIX sockets ? */
613 list_for_each_entry(priv, &tty->tty_files, list) {
614 filp = priv->file;
615 if (filp->f_op->write_iter == redirected_tty_write)
616 cons_filp = filp;
617 if (filp->f_op->write_iter != tty_write)
618 continue;
619 closecount++;
620 __tty_fasync(-1, filp, 0); /* can't block */
621 filp->f_op = &hung_up_tty_fops;
622 }
623 spin_unlock(&tty->files_lock);
624
625 refs = tty_signal_session_leader(tty, exit_session);
626 /* Account for the p->signal references we killed */
627 while (refs--)
628 tty_kref_put(tty);
629
630 tty_ldisc_hangup(tty, cons_filp != NULL);
631
632 spin_lock_irq(&tty->ctrl.lock);
633 clear_bit(TTY_THROTTLED, &tty->flags);
634 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
635 put_pid(tty->ctrl.session);
636 put_pid(tty->ctrl.pgrp);
637 tty->ctrl.session = NULL;
638 tty->ctrl.pgrp = NULL;
639 tty->ctrl.pktstatus = 0;
640 spin_unlock_irq(&tty->ctrl.lock);
641
642 /*
643 * If one of the devices matches a console pointer, we
644 * cannot just call hangup() because that will cause
645 * tty->count and state->count to go out of sync.
646 * So we just call close() the right number of times.
647 */
648 if (cons_filp) {
649 if (tty->ops->close)
650 for (n = 0; n < closecount; n++)
651 tty->ops->close(tty, cons_filp);
652 } else if (tty->ops->hangup)
653 tty->ops->hangup(tty);
654 /*
655 * We don't want to have driver/ldisc interactions beyond the ones
656 * we did here. The driver layer expects no calls after ->hangup()
657 * from the ldisc side, which is now guaranteed.
658 */
659 set_bit(TTY_HUPPED, &tty->flags);
660 clear_bit(TTY_HUPPING, &tty->flags);
661 tty_unlock(tty);
662
663 if (f)
664 fput(f);
665}
666
667static void do_tty_hangup(struct work_struct *work)
668{
669 struct tty_struct *tty =
670 container_of(work, struct tty_struct, hangup_work);
671
672 __tty_hangup(tty, 0);
673}
674
675/**
676 * tty_hangup - trigger a hangup event
677 * @tty: tty to hangup
678 *
679 * A carrier loss (virtual or otherwise) has occurred on @tty. Schedule a
680 * hangup sequence to run after this event.
681 */
682void tty_hangup(struct tty_struct *tty)
683{
684 tty_debug_hangup(tty, "hangup\n");
685 schedule_work(&tty->hangup_work);
686}
687EXPORT_SYMBOL(tty_hangup);
688
689/**
690 * tty_vhangup - process vhangup
691 * @tty: tty to hangup
692 *
693 * The user has asked via system call for the terminal to be hung up. We do
694 * this synchronously so that when the syscall returns the process is complete.
695 * That guarantee is necessary for security reasons.
696 */
697void tty_vhangup(struct tty_struct *tty)
698{
699 tty_debug_hangup(tty, "vhangup\n");
700 __tty_hangup(tty, 0);
701}
702EXPORT_SYMBOL(tty_vhangup);
703
704
705/**
706 * tty_vhangup_self - process vhangup for own ctty
707 *
708 * Perform a vhangup on the current controlling tty
709 */
710void tty_vhangup_self(void)
711{
712 struct tty_struct *tty;
713
714 tty = get_current_tty();
715 if (tty) {
716 tty_vhangup(tty);
717 tty_kref_put(tty);
718 }
719}
720
721/**
722 * tty_vhangup_session - hangup session leader exit
723 * @tty: tty to hangup
724 *
725 * The session leader is exiting and hanging up its controlling terminal.
726 * Every process in the foreground process group is signalled %SIGHUP.
727 *
728 * We do this synchronously so that when the syscall returns the process is
729 * complete. That guarantee is necessary for security reasons.
730 */
731void tty_vhangup_session(struct tty_struct *tty)
732{
733 tty_debug_hangup(tty, "session hangup\n");
734 __tty_hangup(tty, 1);
735}
736
737/**
738 * tty_hung_up_p - was tty hung up
739 * @filp: file pointer of tty
740 *
741 * Return: true if the tty has been subject to a vhangup or a carrier loss
742 */
743int tty_hung_up_p(struct file *filp)
744{
745 return (filp && filp->f_op == &hung_up_tty_fops);
746}
747EXPORT_SYMBOL(tty_hung_up_p);
748
749void __stop_tty(struct tty_struct *tty)
750{
751 if (tty->flow.stopped)
752 return;
753 tty->flow.stopped = true;
754 if (tty->ops->stop)
755 tty->ops->stop(tty);
756}
757
758/**
759 * stop_tty - propagate flow control
760 * @tty: tty to stop
761 *
762 * Perform flow control to the driver. May be called on an already stopped
763 * device and will not re-call the &tty_driver->stop() method.
764 *
765 * This functionality is used by both the line disciplines for halting incoming
766 * flow and by the driver. It may therefore be called from any context, may be
767 * under the tty %atomic_write_lock but not always.
768 *
769 * Locking:
770 * flow.lock
771 */
772void stop_tty(struct tty_struct *tty)
773{
774 unsigned long flags;
775
776 spin_lock_irqsave(&tty->flow.lock, flags);
777 __stop_tty(tty);
778 spin_unlock_irqrestore(&tty->flow.lock, flags);
779}
780EXPORT_SYMBOL(stop_tty);
781
782void __start_tty(struct tty_struct *tty)
783{
784 if (!tty->flow.stopped || tty->flow.tco_stopped)
785 return;
786 tty->flow.stopped = false;
787 if (tty->ops->start)
788 tty->ops->start(tty);
789 tty_wakeup(tty);
790}
791
792/**
793 * start_tty - propagate flow control
794 * @tty: tty to start
795 *
796 * Start a tty that has been stopped if at all possible. If @tty was previously
797 * stopped and is now being started, the &tty_driver->start() method is invoked
798 * and the line discipline woken.
799 *
800 * Locking:
801 * flow.lock
802 */
803void start_tty(struct tty_struct *tty)
804{
805 unsigned long flags;
806
807 spin_lock_irqsave(&tty->flow.lock, flags);
808 __start_tty(tty);
809 spin_unlock_irqrestore(&tty->flow.lock, flags);
810}
811EXPORT_SYMBOL(start_tty);
812
813static void tty_update_time(struct tty_struct *tty, bool mtime)
814{
815 time64_t sec = ktime_get_real_seconds();
816 struct tty_file_private *priv;
817
818 spin_lock(&tty->files_lock);
819 list_for_each_entry(priv, &tty->tty_files, list) {
820 struct inode *inode = file_inode(priv->file);
821 struct timespec64 time = mtime ? inode_get_mtime(inode) : inode_get_atime(inode);
822
823 /*
824 * We only care if the two values differ in anything other than the
825 * lower three bits (i.e every 8 seconds). If so, then we can update
826 * the time of the tty device, otherwise it could be construded as a
827 * security leak to let userspace know the exact timing of the tty.
828 */
829 if ((sec ^ time.tv_sec) & ~7) {
830 if (mtime)
831 inode_set_mtime(inode, sec, 0);
832 else
833 inode_set_atime(inode, sec, 0);
834 }
835 }
836 spin_unlock(&tty->files_lock);
837}
838
839/*
840 * Iterate on the ldisc ->read() function until we've gotten all
841 * the data the ldisc has for us.
842 *
843 * The "cookie" is something that the ldisc read function can fill
844 * in to let us know that there is more data to be had.
845 *
846 * We promise to continue to call the ldisc until it stops returning
847 * data or clears the cookie. The cookie may be something that the
848 * ldisc maintains state for and needs to free.
849 */
850static ssize_t iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
851 struct file *file, struct iov_iter *to)
852{
853 void *cookie = NULL;
854 unsigned long offset = 0;
855 ssize_t retval = 0;
856 size_t copied, count = iov_iter_count(to);
857 u8 kernel_buf[64];
858
859 do {
860 ssize_t size = min(count, sizeof(kernel_buf));
861
862 size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
863 if (!size)
864 break;
865
866 if (size < 0) {
867 /* Did we have an earlier error (ie -EFAULT)? */
868 if (retval)
869 break;
870 retval = size;
871
872 /*
873 * -EOVERFLOW means we didn't have enough space
874 * for a whole packet, and we shouldn't return
875 * a partial result.
876 */
877 if (retval == -EOVERFLOW)
878 offset = 0;
879 break;
880 }
881
882 copied = copy_to_iter(kernel_buf, size, to);
883 offset += copied;
884 count -= copied;
885
886 /*
887 * If the user copy failed, we still need to do another ->read()
888 * call if we had a cookie to let the ldisc clear up.
889 *
890 * But make sure size is zeroed.
891 */
892 if (unlikely(copied != size)) {
893 count = 0;
894 retval = -EFAULT;
895 }
896 } while (cookie);
897
898 /* We always clear tty buffer in case they contained passwords */
899 memzero_explicit(kernel_buf, sizeof(kernel_buf));
900 return offset ? offset : retval;
901}
902
903
904/**
905 * tty_read - read method for tty device files
906 * @iocb: kernel I/O control block
907 * @to: destination for the data read
908 *
909 * Perform the read system call function on this terminal device. Checks
910 * for hung up devices before calling the line discipline method.
911 *
912 * Locking:
913 * Locks the line discipline internally while needed. Multiple read calls
914 * may be outstanding in parallel.
915 */
916static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
917{
918 struct file *file = iocb->ki_filp;
919 struct inode *inode = file_inode(file);
920 struct tty_struct *tty = file_tty(file);
921 struct tty_ldisc *ld;
922 ssize_t ret;
923
924 if (tty_paranoia_check(tty, inode, "tty_read"))
925 return -EIO;
926 if (!tty || tty_io_error(tty))
927 return -EIO;
928
929 /* We want to wait for the line discipline to sort out in this
930 * situation.
931 */
932 ld = tty_ldisc_ref_wait(tty);
933 if (!ld)
934 return hung_up_tty_read(iocb, to);
935 ret = -EIO;
936 if (ld->ops->read)
937 ret = iterate_tty_read(ld, tty, file, to);
938 tty_ldisc_deref(ld);
939
940 if (ret > 0)
941 tty_update_time(tty, false);
942
943 return ret;
944}
945
946void tty_write_unlock(struct tty_struct *tty)
947{
948 mutex_unlock(&tty->atomic_write_lock);
949 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
950}
951
952int tty_write_lock(struct tty_struct *tty, bool ndelay)
953{
954 if (!mutex_trylock(&tty->atomic_write_lock)) {
955 if (ndelay)
956 return -EAGAIN;
957 if (mutex_lock_interruptible(&tty->atomic_write_lock))
958 return -ERESTARTSYS;
959 }
960 return 0;
961}
962
963/*
964 * Split writes up in sane blocksizes to avoid
965 * denial-of-service type attacks
966 */
967static ssize_t iterate_tty_write(struct tty_ldisc *ld, struct tty_struct *tty,
968 struct file *file, struct iov_iter *from)
969{
970 size_t chunk, count = iov_iter_count(from);
971 ssize_t ret, written = 0;
972
973 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
974 if (ret < 0)
975 return ret;
976
977 /*
978 * We chunk up writes into a temporary buffer. This
979 * simplifies low-level drivers immensely, since they
980 * don't have locking issues and user mode accesses.
981 *
982 * But if TTY_NO_WRITE_SPLIT is set, we should use a
983 * big chunk-size..
984 *
985 * The default chunk-size is 2kB, because the NTTY
986 * layer has problems with bigger chunks. It will
987 * claim to be able to handle more characters than
988 * it actually does.
989 */
990 chunk = 2048;
991 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
992 chunk = 65536;
993 if (count < chunk)
994 chunk = count;
995
996 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
997 if (tty->write_cnt < chunk) {
998 u8 *buf_chunk;
999
1000 if (chunk < 1024)
1001 chunk = 1024;
1002
1003 buf_chunk = kvmalloc(chunk, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1004 if (!buf_chunk) {
1005 ret = -ENOMEM;
1006 goto out;
1007 }
1008 kvfree(tty->write_buf);
1009 tty->write_cnt = chunk;
1010 tty->write_buf = buf_chunk;
1011 }
1012
1013 /* Do the write .. */
1014 for (;;) {
1015 size_t size = min(chunk, count);
1016
1017 ret = -EFAULT;
1018 if (copy_from_iter(tty->write_buf, size, from) != size)
1019 break;
1020
1021 ret = ld->ops->write(tty, file, tty->write_buf, size);
1022 if (ret <= 0)
1023 break;
1024
1025 written += ret;
1026 if (ret > size)
1027 break;
1028
1029 /* FIXME! Have Al check this! */
1030 if (ret != size)
1031 iov_iter_revert(from, size-ret);
1032
1033 count -= ret;
1034 if (!count)
1035 break;
1036 ret = -ERESTARTSYS;
1037 if (signal_pending(current))
1038 break;
1039 cond_resched();
1040 }
1041 if (written) {
1042 tty_update_time(tty, true);
1043 ret = written;
1044 }
1045out:
1046 tty_write_unlock(tty);
1047 return ret;
1048}
1049
1050#ifdef CONFIG_PRINT_QUOTA_WARNING
1051/**
1052 * tty_write_message - write a message to a certain tty, not just the console.
1053 * @tty: the destination tty_struct
1054 * @msg: the message to write
1055 *
1056 * This is used for messages that need to be redirected to a specific tty. We
1057 * don't put it into the syslog queue right now maybe in the future if really
1058 * needed.
1059 *
1060 * We must still hold the BTM and test the CLOSING flag for the moment.
1061 *
1062 * This function is DEPRECATED, do not use in new code.
1063 */
1064void tty_write_message(struct tty_struct *tty, char *msg)
1065{
1066 if (tty) {
1067 mutex_lock(&tty->atomic_write_lock);
1068 tty_lock(tty);
1069 if (tty->ops->write && tty->count > 0)
1070 tty->ops->write(tty, msg, strlen(msg));
1071 tty_unlock(tty);
1072 tty_write_unlock(tty);
1073 }
1074}
1075#endif
1076
1077static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_iter *from)
1078{
1079 struct tty_struct *tty = file_tty(file);
1080 struct tty_ldisc *ld;
1081 ssize_t ret;
1082
1083 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1084 return -EIO;
1085 if (!tty || !tty->ops->write || tty_io_error(tty))
1086 return -EIO;
1087 /* Short term debug to catch buggy drivers */
1088 if (tty->ops->write_room == NULL)
1089 tty_err(tty, "missing write_room method\n");
1090 ld = tty_ldisc_ref_wait(tty);
1091 if (!ld)
1092 return hung_up_tty_write(iocb, from);
1093 if (!ld->ops->write)
1094 ret = -EIO;
1095 else
1096 ret = iterate_tty_write(ld, tty, file, from);
1097 tty_ldisc_deref(ld);
1098 return ret;
1099}
1100
1101/**
1102 * tty_write - write method for tty device file
1103 * @iocb: kernel I/O control block
1104 * @from: iov_iter with data to write
1105 *
1106 * Write data to a tty device via the line discipline.
1107 *
1108 * Locking:
1109 * Locks the line discipline as required
1110 * Writes to the tty driver are serialized by the atomic_write_lock
1111 * and are then processed in chunks to the device. The line
1112 * discipline write method will not be invoked in parallel for
1113 * each device.
1114 */
1115static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from)
1116{
1117 return file_tty_write(iocb->ki_filp, iocb, from);
1118}
1119
1120ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter)
1121{
1122 struct file *p = NULL;
1123
1124 spin_lock(&redirect_lock);
1125 if (redirect)
1126 p = get_file(redirect);
1127 spin_unlock(&redirect_lock);
1128
1129 /*
1130 * We know the redirected tty is just another tty, we can
1131 * call file_tty_write() directly with that file pointer.
1132 */
1133 if (p) {
1134 ssize_t res;
1135
1136 res = file_tty_write(p, iocb, iter);
1137 fput(p);
1138 return res;
1139 }
1140 return tty_write(iocb, iter);
1141}
1142
1143/**
1144 * tty_send_xchar - send priority character
1145 * @tty: the tty to send to
1146 * @ch: xchar to send
1147 *
1148 * Send a high priority character to the tty even if stopped.
1149 *
1150 * Locking: none for xchar method, write ordering for write method.
1151 */
1152int tty_send_xchar(struct tty_struct *tty, u8 ch)
1153{
1154 bool was_stopped = tty->flow.stopped;
1155
1156 if (tty->ops->send_xchar) {
1157 down_read(&tty->termios_rwsem);
1158 tty->ops->send_xchar(tty, ch);
1159 up_read(&tty->termios_rwsem);
1160 return 0;
1161 }
1162
1163 if (tty_write_lock(tty, false) < 0)
1164 return -ERESTARTSYS;
1165
1166 down_read(&tty->termios_rwsem);
1167 if (was_stopped)
1168 start_tty(tty);
1169 tty->ops->write(tty, &ch, 1);
1170 if (was_stopped)
1171 stop_tty(tty);
1172 up_read(&tty->termios_rwsem);
1173 tty_write_unlock(tty);
1174 return 0;
1175}
1176
1177/**
1178 * pty_line_name - generate name for a pty
1179 * @driver: the tty driver in use
1180 * @index: the minor number
1181 * @p: output buffer of at least 6 bytes
1182 *
1183 * Generate a name from a @driver reference and write it to the output buffer
1184 * @p.
1185 *
1186 * Locking: None
1187 */
1188static void pty_line_name(struct tty_driver *driver, int index, char *p)
1189{
1190 static const char ptychar[] = "pqrstuvwxyzabcde";
1191 int i = index + driver->name_base;
1192 /* ->name is initialized to "ttyp", but "tty" is expected */
1193 sprintf(p, "%s%c%x",
1194 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1195 ptychar[i >> 4 & 0xf], i & 0xf);
1196}
1197
1198/**
1199 * tty_line_name - generate name for a tty
1200 * @driver: the tty driver in use
1201 * @index: the minor number
1202 * @p: output buffer of at least 7 bytes
1203 *
1204 * Generate a name from a @driver reference and write it to the output buffer
1205 * @p.
1206 *
1207 * Locking: None
1208 */
1209static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1210{
1211 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1212 return sprintf(p, "%s", driver->name);
1213 else
1214 return sprintf(p, "%s%d", driver->name,
1215 index + driver->name_base);
1216}
1217
1218/**
1219 * tty_driver_lookup_tty() - find an existing tty, if any
1220 * @driver: the driver for the tty
1221 * @file: file object
1222 * @idx: the minor number
1223 *
1224 * Return: the tty, if found. If not found, return %NULL or ERR_PTR() if the
1225 * driver lookup() method returns an error.
1226 *
1227 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1228 */
1229static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1230 struct file *file, int idx)
1231{
1232 struct tty_struct *tty;
1233
1234 if (driver->ops->lookup) {
1235 if (!file)
1236 tty = ERR_PTR(-EIO);
1237 else
1238 tty = driver->ops->lookup(driver, file, idx);
1239 } else {
1240 if (idx >= driver->num)
1241 return ERR_PTR(-EINVAL);
1242 tty = driver->ttys[idx];
1243 }
1244 if (!IS_ERR(tty))
1245 tty_kref_get(tty);
1246 return tty;
1247}
1248
1249/**
1250 * tty_init_termios - helper for termios setup
1251 * @tty: the tty to set up
1252 *
1253 * Initialise the termios structure for this tty. This runs under the
1254 * %tty_mutex currently so we can be relaxed about ordering.
1255 */
1256void tty_init_termios(struct tty_struct *tty)
1257{
1258 struct ktermios *tp;
1259 int idx = tty->index;
1260
1261 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1262 tty->termios = tty->driver->init_termios;
1263 else {
1264 /* Check for lazy saved data */
1265 tp = tty->driver->termios[idx];
1266 if (tp != NULL) {
1267 tty->termios = *tp;
1268 tty->termios.c_line = tty->driver->init_termios.c_line;
1269 } else
1270 tty->termios = tty->driver->init_termios;
1271 }
1272 /* Compatibility until drivers always set this */
1273 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1274 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1275}
1276EXPORT_SYMBOL_GPL(tty_init_termios);
1277
1278/**
1279 * tty_standard_install - usual tty->ops->install
1280 * @driver: the driver for the tty
1281 * @tty: the tty
1282 *
1283 * If the @driver overrides @tty->ops->install, it still can call this function
1284 * to perform the standard install operations.
1285 */
1286int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1287{
1288 tty_init_termios(tty);
1289 tty_driver_kref_get(driver);
1290 tty->count++;
1291 driver->ttys[tty->index] = tty;
1292 return 0;
1293}
1294EXPORT_SYMBOL_GPL(tty_standard_install);
1295
1296/**
1297 * tty_driver_install_tty() - install a tty entry in the driver
1298 * @driver: the driver for the tty
1299 * @tty: the tty
1300 *
1301 * Install a tty object into the driver tables. The @tty->index field will be
1302 * set by the time this is called. This method is responsible for ensuring any
1303 * need additional structures are allocated and configured.
1304 *
1305 * Locking: tty_mutex for now
1306 */
1307static int tty_driver_install_tty(struct tty_driver *driver,
1308 struct tty_struct *tty)
1309{
1310 return driver->ops->install ? driver->ops->install(driver, tty) :
1311 tty_standard_install(driver, tty);
1312}
1313
1314/**
1315 * tty_driver_remove_tty() - remove a tty from the driver tables
1316 * @driver: the driver for the tty
1317 * @tty: tty to remove
1318 *
1319 * Remove a tty object from the driver tables. The tty->index field will be set
1320 * by the time this is called.
1321 *
1322 * Locking: tty_mutex for now
1323 */
1324static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1325{
1326 if (driver->ops->remove)
1327 driver->ops->remove(driver, tty);
1328 else
1329 driver->ttys[tty->index] = NULL;
1330}
1331
1332/**
1333 * tty_reopen() - fast re-open of an open tty
1334 * @tty: the tty to open
1335 *
1336 * Re-opens on master ptys are not allowed and return -%EIO.
1337 *
1338 * Locking: Caller must hold tty_lock
1339 * Return: 0 on success, -errno on error.
1340 */
1341static int tty_reopen(struct tty_struct *tty)
1342{
1343 struct tty_driver *driver = tty->driver;
1344 struct tty_ldisc *ld;
1345 int retval = 0;
1346
1347 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1348 driver->subtype == PTY_TYPE_MASTER)
1349 return -EIO;
1350
1351 if (!tty->count)
1352 return -EAGAIN;
1353
1354 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1355 return -EBUSY;
1356
1357 ld = tty_ldisc_ref_wait(tty);
1358 if (ld) {
1359 tty_ldisc_deref(ld);
1360 } else {
1361 retval = tty_ldisc_lock(tty, 5 * HZ);
1362 if (retval)
1363 return retval;
1364
1365 if (!tty->ldisc)
1366 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1367 tty_ldisc_unlock(tty);
1368 }
1369
1370 if (retval == 0)
1371 tty->count++;
1372
1373 return retval;
1374}
1375
1376/**
1377 * tty_init_dev - initialise a tty device
1378 * @driver: tty driver we are opening a device on
1379 * @idx: device index
1380 *
1381 * Prepare a tty device. This may not be a "new" clean device but could also be
1382 * an active device. The pty drivers require special handling because of this.
1383 *
1384 * Locking:
1385 * The function is called under the tty_mutex, which protects us from the
1386 * tty struct or driver itself going away.
1387 *
1388 * On exit the tty device has the line discipline attached and a reference
1389 * count of 1. If a pair was created for pty/tty use and the other was a pty
1390 * master then it too has a reference count of 1.
1391 *
1392 * WSH 06/09/97: Rewritten to remove races and properly clean up after a failed
1393 * open. The new code protects the open with a mutex, so it's really quite
1394 * straightforward. The mutex locking can probably be relaxed for the (most
1395 * common) case of reopening a tty.
1396 *
1397 * Return: new tty structure
1398 */
1399struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1400{
1401 struct tty_struct *tty;
1402 int retval;
1403
1404 /*
1405 * First time open is complex, especially for PTY devices.
1406 * This code guarantees that either everything succeeds and the
1407 * TTY is ready for operation, or else the table slots are vacated
1408 * and the allocated memory released. (Except that the termios
1409 * may be retained.)
1410 */
1411
1412 if (!try_module_get(driver->owner))
1413 return ERR_PTR(-ENODEV);
1414
1415 tty = alloc_tty_struct(driver, idx);
1416 if (!tty) {
1417 retval = -ENOMEM;
1418 goto err_module_put;
1419 }
1420
1421 tty_lock(tty);
1422 retval = tty_driver_install_tty(driver, tty);
1423 if (retval < 0)
1424 goto err_free_tty;
1425
1426 if (!tty->port)
1427 tty->port = driver->ports[idx];
1428
1429 if (WARN_RATELIMIT(!tty->port,
1430 "%s: %s driver does not set tty->port. This would crash the kernel. Fix the driver!\n",
1431 __func__, tty->driver->name)) {
1432 retval = -EINVAL;
1433 goto err_release_lock;
1434 }
1435
1436 retval = tty_ldisc_lock(tty, 5 * HZ);
1437 if (retval)
1438 goto err_release_lock;
1439 tty->port->itty = tty;
1440
1441 /*
1442 * Structures all installed ... call the ldisc open routines.
1443 * If we fail here just call release_tty to clean up. No need
1444 * to decrement the use counts, as release_tty doesn't care.
1445 */
1446 retval = tty_ldisc_setup(tty, tty->link);
1447 if (retval)
1448 goto err_release_tty;
1449 tty_ldisc_unlock(tty);
1450 /* Return the tty locked so that it cannot vanish under the caller */
1451 return tty;
1452
1453err_free_tty:
1454 tty_unlock(tty);
1455 free_tty_struct(tty);
1456err_module_put:
1457 module_put(driver->owner);
1458 return ERR_PTR(retval);
1459
1460 /* call the tty release_tty routine to clean out this slot */
1461err_release_tty:
1462 tty_ldisc_unlock(tty);
1463 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1464 retval, idx);
1465err_release_lock:
1466 tty_unlock(tty);
1467 release_tty(tty, idx);
1468 return ERR_PTR(retval);
1469}
1470
1471/**
1472 * tty_save_termios() - save tty termios data in driver table
1473 * @tty: tty whose termios data to save
1474 *
1475 * Locking: Caller guarantees serialisation with tty_init_termios().
1476 */
1477void tty_save_termios(struct tty_struct *tty)
1478{
1479 struct ktermios *tp;
1480 int idx = tty->index;
1481
1482 /* If the port is going to reset then it has no termios to save */
1483 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1484 return;
1485
1486 /* Stash the termios data */
1487 tp = tty->driver->termios[idx];
1488 if (tp == NULL) {
1489 tp = kmalloc(sizeof(*tp), GFP_KERNEL);
1490 if (tp == NULL)
1491 return;
1492 tty->driver->termios[idx] = tp;
1493 }
1494 *tp = tty->termios;
1495}
1496EXPORT_SYMBOL_GPL(tty_save_termios);
1497
1498/**
1499 * tty_flush_works - flush all works of a tty/pty pair
1500 * @tty: tty device to flush works for (or either end of a pty pair)
1501 *
1502 * Sync flush all works belonging to @tty (and the 'other' tty).
1503 */
1504static void tty_flush_works(struct tty_struct *tty)
1505{
1506 flush_work(&tty->SAK_work);
1507 flush_work(&tty->hangup_work);
1508 if (tty->link) {
1509 flush_work(&tty->link->SAK_work);
1510 flush_work(&tty->link->hangup_work);
1511 }
1512}
1513
1514/**
1515 * release_one_tty - release tty structure memory
1516 * @work: work of tty we are obliterating
1517 *
1518 * Releases memory associated with a tty structure, and clears out the
1519 * driver table slots. This function is called when a device is no longer
1520 * in use. It also gets called when setup of a device fails.
1521 *
1522 * Locking:
1523 * takes the file list lock internally when working on the list of ttys
1524 * that the driver keeps.
1525 *
1526 * This method gets called from a work queue so that the driver private
1527 * cleanup ops can sleep (needed for USB at least)
1528 */
1529static void release_one_tty(struct work_struct *work)
1530{
1531 struct tty_struct *tty =
1532 container_of(work, struct tty_struct, hangup_work);
1533 struct tty_driver *driver = tty->driver;
1534 struct module *owner = driver->owner;
1535
1536 if (tty->ops->cleanup)
1537 tty->ops->cleanup(tty);
1538
1539 tty_driver_kref_put(driver);
1540 module_put(owner);
1541
1542 spin_lock(&tty->files_lock);
1543 list_del_init(&tty->tty_files);
1544 spin_unlock(&tty->files_lock);
1545
1546 put_pid(tty->ctrl.pgrp);
1547 put_pid(tty->ctrl.session);
1548 free_tty_struct(tty);
1549}
1550
1551static void queue_release_one_tty(struct kref *kref)
1552{
1553 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1554
1555 /* The hangup queue is now free so we can reuse it rather than
1556 * waste a chunk of memory for each port.
1557 */
1558 INIT_WORK(&tty->hangup_work, release_one_tty);
1559 schedule_work(&tty->hangup_work);
1560}
1561
1562/**
1563 * tty_kref_put - release a tty kref
1564 * @tty: tty device
1565 *
1566 * Release a reference to the @tty device and if need be let the kref layer
1567 * destruct the object for us.
1568 */
1569void tty_kref_put(struct tty_struct *tty)
1570{
1571 if (tty)
1572 kref_put(&tty->kref, queue_release_one_tty);
1573}
1574EXPORT_SYMBOL(tty_kref_put);
1575
1576/**
1577 * release_tty - release tty structure memory
1578 * @tty: tty device release
1579 * @idx: index of the tty device release
1580 *
1581 * Release both @tty and a possible linked partner (think pty pair),
1582 * and decrement the refcount of the backing module.
1583 *
1584 * Locking:
1585 * tty_mutex
1586 * takes the file list lock internally when working on the list of ttys
1587 * that the driver keeps.
1588 */
1589static void release_tty(struct tty_struct *tty, int idx)
1590{
1591 /* This should always be true but check for the moment */
1592 WARN_ON(tty->index != idx);
1593 WARN_ON(!mutex_is_locked(&tty_mutex));
1594 if (tty->ops->shutdown)
1595 tty->ops->shutdown(tty);
1596 tty_save_termios(tty);
1597 tty_driver_remove_tty(tty->driver, tty);
1598 if (tty->port)
1599 tty->port->itty = NULL;
1600 if (tty->link)
1601 tty->link->port->itty = NULL;
1602 if (tty->port)
1603 tty_buffer_cancel_work(tty->port);
1604 if (tty->link)
1605 tty_buffer_cancel_work(tty->link->port);
1606
1607 tty_kref_put(tty->link);
1608 tty_kref_put(tty);
1609}
1610
1611/**
1612 * tty_release_checks - check a tty before real release
1613 * @tty: tty to check
1614 * @idx: index of the tty
1615 *
1616 * Performs some paranoid checking before true release of the @tty. This is a
1617 * no-op unless %TTY_PARANOIA_CHECK is defined.
1618 */
1619static int tty_release_checks(struct tty_struct *tty, int idx)
1620{
1621#ifdef TTY_PARANOIA_CHECK
1622 if (idx < 0 || idx >= tty->driver->num) {
1623 tty_debug(tty, "bad idx %d\n", idx);
1624 return -1;
1625 }
1626
1627 /* not much to check for devpts */
1628 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1629 return 0;
1630
1631 if (tty != tty->driver->ttys[idx]) {
1632 tty_debug(tty, "bad driver table[%d] = %p\n",
1633 idx, tty->driver->ttys[idx]);
1634 return -1;
1635 }
1636 if (tty->driver->other) {
1637 struct tty_struct *o_tty = tty->link;
1638
1639 if (o_tty != tty->driver->other->ttys[idx]) {
1640 tty_debug(tty, "bad other table[%d] = %p\n",
1641 idx, tty->driver->other->ttys[idx]);
1642 return -1;
1643 }
1644 if (o_tty->link != tty) {
1645 tty_debug(tty, "bad link = %p\n", o_tty->link);
1646 return -1;
1647 }
1648 }
1649#endif
1650 return 0;
1651}
1652
1653/**
1654 * tty_kclose - closes tty opened by tty_kopen
1655 * @tty: tty device
1656 *
1657 * Performs the final steps to release and free a tty device. It is the same as
1658 * tty_release_struct() except that it also resets %TTY_PORT_KOPENED flag on
1659 * @tty->port.
1660 */
1661void tty_kclose(struct tty_struct *tty)
1662{
1663 /*
1664 * Ask the line discipline code to release its structures
1665 */
1666 tty_ldisc_release(tty);
1667
1668 /* Wait for pending work before tty destruction commences */
1669 tty_flush_works(tty);
1670
1671 tty_debug_hangup(tty, "freeing structure\n");
1672 /*
1673 * The release_tty function takes care of the details of clearing
1674 * the slots and preserving the termios structure.
1675 */
1676 mutex_lock(&tty_mutex);
1677 tty_port_set_kopened(tty->port, 0);
1678 release_tty(tty, tty->index);
1679 mutex_unlock(&tty_mutex);
1680}
1681EXPORT_SYMBOL_GPL(tty_kclose);
1682
1683/**
1684 * tty_release_struct - release a tty struct
1685 * @tty: tty device
1686 * @idx: index of the tty
1687 *
1688 * Performs the final steps to release and free a tty device. It is roughly the
1689 * reverse of tty_init_dev().
1690 */
1691void tty_release_struct(struct tty_struct *tty, int idx)
1692{
1693 /*
1694 * Ask the line discipline code to release its structures
1695 */
1696 tty_ldisc_release(tty);
1697
1698 /* Wait for pending work before tty destruction commmences */
1699 tty_flush_works(tty);
1700
1701 tty_debug_hangup(tty, "freeing structure\n");
1702 /*
1703 * The release_tty function takes care of the details of clearing
1704 * the slots and preserving the termios structure.
1705 */
1706 mutex_lock(&tty_mutex);
1707 release_tty(tty, idx);
1708 mutex_unlock(&tty_mutex);
1709}
1710EXPORT_SYMBOL_GPL(tty_release_struct);
1711
1712/**
1713 * tty_release - vfs callback for close
1714 * @inode: inode of tty
1715 * @filp: file pointer for handle to tty
1716 *
1717 * Called the last time each file handle is closed that references this tty.
1718 * There may however be several such references.
1719 *
1720 * Locking:
1721 * Takes BKL. See tty_release_dev().
1722 *
1723 * Even releasing the tty structures is a tricky business. We have to be very
1724 * careful that the structures are all released at the same time, as interrupts
1725 * might otherwise get the wrong pointers.
1726 *
1727 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1728 * lead to double frees or releasing memory still in use.
1729 */
1730int tty_release(struct inode *inode, struct file *filp)
1731{
1732 struct tty_struct *tty = file_tty(filp);
1733 struct tty_struct *o_tty = NULL;
1734 int do_sleep, final;
1735 int idx;
1736 long timeout = 0;
1737 int once = 1;
1738
1739 if (tty_paranoia_check(tty, inode, __func__))
1740 return 0;
1741
1742 tty_lock(tty);
1743 check_tty_count(tty, __func__);
1744
1745 __tty_fasync(-1, filp, 0);
1746
1747 idx = tty->index;
1748 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1749 tty->driver->subtype == PTY_TYPE_MASTER)
1750 o_tty = tty->link;
1751
1752 if (tty_release_checks(tty, idx)) {
1753 tty_unlock(tty);
1754 return 0;
1755 }
1756
1757 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1758
1759 if (tty->ops->close)
1760 tty->ops->close(tty, filp);
1761
1762 /* If tty is pty master, lock the slave pty (stable lock order) */
1763 tty_lock_slave(o_tty);
1764
1765 /*
1766 * Sanity check: if tty->count is going to zero, there shouldn't be
1767 * any waiters on tty->read_wait or tty->write_wait. We test the
1768 * wait queues and kick everyone out _before_ actually starting to
1769 * close. This ensures that we won't block while releasing the tty
1770 * structure.
1771 *
1772 * The test for the o_tty closing is necessary, since the master and
1773 * slave sides may close in any order. If the slave side closes out
1774 * first, its count will be one, since the master side holds an open.
1775 * Thus this test wouldn't be triggered at the time the slave closed,
1776 * so we do it now.
1777 */
1778 while (1) {
1779 do_sleep = 0;
1780
1781 if (tty->count <= 1) {
1782 if (waitqueue_active(&tty->read_wait)) {
1783 wake_up_poll(&tty->read_wait, EPOLLIN);
1784 do_sleep++;
1785 }
1786 if (waitqueue_active(&tty->write_wait)) {
1787 wake_up_poll(&tty->write_wait, EPOLLOUT);
1788 do_sleep++;
1789 }
1790 }
1791 if (o_tty && o_tty->count <= 1) {
1792 if (waitqueue_active(&o_tty->read_wait)) {
1793 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1794 do_sleep++;
1795 }
1796 if (waitqueue_active(&o_tty->write_wait)) {
1797 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1798 do_sleep++;
1799 }
1800 }
1801 if (!do_sleep)
1802 break;
1803
1804 if (once) {
1805 once = 0;
1806 tty_warn(tty, "read/write wait queue active!\n");
1807 }
1808 schedule_timeout_killable(timeout);
1809 if (timeout < 120 * HZ)
1810 timeout = 2 * timeout + 1;
1811 else
1812 timeout = MAX_SCHEDULE_TIMEOUT;
1813 }
1814
1815 if (o_tty) {
1816 if (--o_tty->count < 0) {
1817 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1818 o_tty->count = 0;
1819 }
1820 }
1821 if (--tty->count < 0) {
1822 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1823 tty->count = 0;
1824 }
1825
1826 /*
1827 * We've decremented tty->count, so we need to remove this file
1828 * descriptor off the tty->tty_files list; this serves two
1829 * purposes:
1830 * - check_tty_count sees the correct number of file descriptors
1831 * associated with this tty.
1832 * - do_tty_hangup no longer sees this file descriptor as
1833 * something that needs to be handled for hangups.
1834 */
1835 tty_del_file(filp);
1836
1837 /*
1838 * Perform some housekeeping before deciding whether to return.
1839 *
1840 * If _either_ side is closing, make sure there aren't any
1841 * processes that still think tty or o_tty is their controlling
1842 * tty.
1843 */
1844 if (!tty->count) {
1845 read_lock(&tasklist_lock);
1846 session_clear_tty(tty->ctrl.session);
1847 if (o_tty)
1848 session_clear_tty(o_tty->ctrl.session);
1849 read_unlock(&tasklist_lock);
1850 }
1851
1852 /* check whether both sides are closing ... */
1853 final = !tty->count && !(o_tty && o_tty->count);
1854
1855 tty_unlock_slave(o_tty);
1856 tty_unlock(tty);
1857
1858 /* At this point, the tty->count == 0 should ensure a dead tty
1859 * cannot be re-opened by a racing opener.
1860 */
1861
1862 if (!final)
1863 return 0;
1864
1865 tty_debug_hangup(tty, "final close\n");
1866
1867 tty_release_struct(tty, idx);
1868 return 0;
1869}
1870
1871/**
1872 * tty_open_current_tty - get locked tty of current task
1873 * @device: device number
1874 * @filp: file pointer to tty
1875 * @return: locked tty of the current task iff @device is /dev/tty
1876 *
1877 * Performs a re-open of the current task's controlling tty.
1878 *
1879 * We cannot return driver and index like for the other nodes because devpts
1880 * will not work then. It expects inodes to be from devpts FS.
1881 */
1882static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1883{
1884 struct tty_struct *tty;
1885 int retval;
1886
1887 if (device != MKDEV(TTYAUX_MAJOR, 0))
1888 return NULL;
1889
1890 tty = get_current_tty();
1891 if (!tty)
1892 return ERR_PTR(-ENXIO);
1893
1894 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1895 /* noctty = 1; */
1896 tty_lock(tty);
1897 tty_kref_put(tty); /* safe to drop the kref now */
1898
1899 retval = tty_reopen(tty);
1900 if (retval < 0) {
1901 tty_unlock(tty);
1902 tty = ERR_PTR(retval);
1903 }
1904 return tty;
1905}
1906
1907/**
1908 * tty_lookup_driver - lookup a tty driver for a given device file
1909 * @device: device number
1910 * @filp: file pointer to tty
1911 * @index: index for the device in the @return driver
1912 *
1913 * If returned value is not erroneous, the caller is responsible to decrement
1914 * the refcount by tty_driver_kref_put().
1915 *
1916 * Locking: %tty_mutex protects get_tty_driver()
1917 *
1918 * Return: driver for this inode (with increased refcount)
1919 */
1920static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1921 int *index)
1922{
1923 struct tty_driver *driver = NULL;
1924
1925 switch (device) {
1926#ifdef CONFIG_VT
1927 case MKDEV(TTY_MAJOR, 0): {
1928 extern struct tty_driver *console_driver;
1929
1930 driver = tty_driver_kref_get(console_driver);
1931 *index = fg_console;
1932 break;
1933 }
1934#endif
1935 case MKDEV(TTYAUX_MAJOR, 1): {
1936 struct tty_driver *console_driver = console_device(index);
1937
1938 if (console_driver) {
1939 driver = tty_driver_kref_get(console_driver);
1940 if (driver && filp) {
1941 /* Don't let /dev/console block */
1942 filp->f_flags |= O_NONBLOCK;
1943 break;
1944 }
1945 }
1946 if (driver)
1947 tty_driver_kref_put(driver);
1948 return ERR_PTR(-ENODEV);
1949 }
1950 default:
1951 driver = get_tty_driver(device, index);
1952 if (!driver)
1953 return ERR_PTR(-ENODEV);
1954 break;
1955 }
1956 return driver;
1957}
1958
1959static struct tty_struct *tty_kopen(dev_t device, int shared)
1960{
1961 struct tty_struct *tty;
1962 struct tty_driver *driver;
1963 int index = -1;
1964
1965 mutex_lock(&tty_mutex);
1966 driver = tty_lookup_driver(device, NULL, &index);
1967 if (IS_ERR(driver)) {
1968 mutex_unlock(&tty_mutex);
1969 return ERR_CAST(driver);
1970 }
1971
1972 /* check whether we're reopening an existing tty */
1973 tty = tty_driver_lookup_tty(driver, NULL, index);
1974 if (IS_ERR(tty) || shared)
1975 goto out;
1976
1977 if (tty) {
1978 /* drop kref from tty_driver_lookup_tty() */
1979 tty_kref_put(tty);
1980 tty = ERR_PTR(-EBUSY);
1981 } else { /* tty_init_dev returns tty with the tty_lock held */
1982 tty = tty_init_dev(driver, index);
1983 if (IS_ERR(tty))
1984 goto out;
1985 tty_port_set_kopened(tty->port, 1);
1986 }
1987out:
1988 mutex_unlock(&tty_mutex);
1989 tty_driver_kref_put(driver);
1990 return tty;
1991}
1992
1993/**
1994 * tty_kopen_exclusive - open a tty device for kernel
1995 * @device: dev_t of device to open
1996 *
1997 * Opens tty exclusively for kernel. Performs the driver lookup, makes sure
1998 * it's not already opened and performs the first-time tty initialization.
1999 *
2000 * Claims the global %tty_mutex to serialize:
2001 * * concurrent first-time tty initialization
2002 * * concurrent tty driver removal w/ lookup
2003 * * concurrent tty removal from driver table
2004 *
2005 * Return: the locked initialized &tty_struct
2006 */
2007struct tty_struct *tty_kopen_exclusive(dev_t device)
2008{
2009 return tty_kopen(device, 0);
2010}
2011EXPORT_SYMBOL_GPL(tty_kopen_exclusive);
2012
2013/**
2014 * tty_kopen_shared - open a tty device for shared in-kernel use
2015 * @device: dev_t of device to open
2016 *
2017 * Opens an already existing tty for in-kernel use. Compared to
2018 * tty_kopen_exclusive() above it doesn't ensure to be the only user.
2019 *
2020 * Locking: identical to tty_kopen() above.
2021 */
2022struct tty_struct *tty_kopen_shared(dev_t device)
2023{
2024 return tty_kopen(device, 1);
2025}
2026EXPORT_SYMBOL_GPL(tty_kopen_shared);
2027
2028/**
2029 * tty_open_by_driver - open a tty device
2030 * @device: dev_t of device to open
2031 * @filp: file pointer to tty
2032 *
2033 * Performs the driver lookup, checks for a reopen, or otherwise performs the
2034 * first-time tty initialization.
2035 *
2036 *
2037 * Claims the global tty_mutex to serialize:
2038 * * concurrent first-time tty initialization
2039 * * concurrent tty driver removal w/ lookup
2040 * * concurrent tty removal from driver table
2041 *
2042 * Return: the locked initialized or re-opened &tty_struct
2043 */
2044static struct tty_struct *tty_open_by_driver(dev_t device,
2045 struct file *filp)
2046{
2047 struct tty_struct *tty;
2048 struct tty_driver *driver = NULL;
2049 int index = -1;
2050 int retval;
2051
2052 mutex_lock(&tty_mutex);
2053 driver = tty_lookup_driver(device, filp, &index);
2054 if (IS_ERR(driver)) {
2055 mutex_unlock(&tty_mutex);
2056 return ERR_CAST(driver);
2057 }
2058
2059 /* check whether we're reopening an existing tty */
2060 tty = tty_driver_lookup_tty(driver, filp, index);
2061 if (IS_ERR(tty)) {
2062 mutex_unlock(&tty_mutex);
2063 goto out;
2064 }
2065
2066 if (tty) {
2067 if (tty_port_kopened(tty->port)) {
2068 tty_kref_put(tty);
2069 mutex_unlock(&tty_mutex);
2070 tty = ERR_PTR(-EBUSY);
2071 goto out;
2072 }
2073 mutex_unlock(&tty_mutex);
2074 retval = tty_lock_interruptible(tty);
2075 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2076 if (retval) {
2077 if (retval == -EINTR)
2078 retval = -ERESTARTSYS;
2079 tty = ERR_PTR(retval);
2080 goto out;
2081 }
2082 retval = tty_reopen(tty);
2083 if (retval < 0) {
2084 tty_unlock(tty);
2085 tty = ERR_PTR(retval);
2086 }
2087 } else { /* Returns with the tty_lock held for now */
2088 tty = tty_init_dev(driver, index);
2089 mutex_unlock(&tty_mutex);
2090 }
2091out:
2092 tty_driver_kref_put(driver);
2093 return tty;
2094}
2095
2096/**
2097 * tty_open - open a tty device
2098 * @inode: inode of device file
2099 * @filp: file pointer to tty
2100 *
2101 * tty_open() and tty_release() keep up the tty count that contains the number
2102 * of opens done on a tty. We cannot use the inode-count, as different inodes
2103 * might point to the same tty.
2104 *
2105 * Open-counting is needed for pty masters, as well as for keeping track of
2106 * serial lines: DTR is dropped when the last close happens.
2107 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2108 *
2109 * The termios state of a pty is reset on the first open so that settings don't
2110 * persist across reuse.
2111 *
2112 * Locking:
2113 * * %tty_mutex protects tty, tty_lookup_driver() and tty_init_dev().
2114 * * @tty->count should protect the rest.
2115 * * ->siglock protects ->signal/->sighand
2116 *
2117 * Note: the tty_unlock/lock cases without a ref are only safe due to %tty_mutex
2118 */
2119static int tty_open(struct inode *inode, struct file *filp)
2120{
2121 struct tty_struct *tty;
2122 int noctty, retval;
2123 dev_t device = inode->i_rdev;
2124 unsigned saved_flags = filp->f_flags;
2125
2126 nonseekable_open(inode, filp);
2127
2128retry_open:
2129 retval = tty_alloc_file(filp);
2130 if (retval)
2131 return -ENOMEM;
2132
2133 tty = tty_open_current_tty(device, filp);
2134 if (!tty)
2135 tty = tty_open_by_driver(device, filp);
2136
2137 if (IS_ERR(tty)) {
2138 tty_free_file(filp);
2139 retval = PTR_ERR(tty);
2140 if (retval != -EAGAIN || signal_pending(current))
2141 return retval;
2142 schedule();
2143 goto retry_open;
2144 }
2145
2146 tty_add_file(tty, filp);
2147
2148 check_tty_count(tty, __func__);
2149 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2150
2151 if (tty->ops->open)
2152 retval = tty->ops->open(tty, filp);
2153 else
2154 retval = -ENODEV;
2155 filp->f_flags = saved_flags;
2156
2157 if (retval) {
2158 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2159
2160 tty_unlock(tty); /* need to call tty_release without BTM */
2161 tty_release(inode, filp);
2162 if (retval != -ERESTARTSYS)
2163 return retval;
2164
2165 if (signal_pending(current))
2166 return retval;
2167
2168 schedule();
2169 /*
2170 * Need to reset f_op in case a hangup happened.
2171 */
2172 if (tty_hung_up_p(filp))
2173 filp->f_op = &tty_fops;
2174 goto retry_open;
2175 }
2176 clear_bit(TTY_HUPPED, &tty->flags);
2177
2178 noctty = (filp->f_flags & O_NOCTTY) ||
2179 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2180 device == MKDEV(TTYAUX_MAJOR, 1) ||
2181 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2182 tty->driver->subtype == PTY_TYPE_MASTER);
2183 if (!noctty)
2184 tty_open_proc_set_tty(filp, tty);
2185 tty_unlock(tty);
2186 return 0;
2187}
2188
2189
2190/**
2191 * tty_poll - check tty status
2192 * @filp: file being polled
2193 * @wait: poll wait structures to update
2194 *
2195 * Call the line discipline polling method to obtain the poll status of the
2196 * device.
2197 *
2198 * Locking: locks called line discipline but ldisc poll method may be
2199 * re-entered freely by other callers.
2200 */
2201static __poll_t tty_poll(struct file *filp, poll_table *wait)
2202{
2203 struct tty_struct *tty = file_tty(filp);
2204 struct tty_ldisc *ld;
2205 __poll_t ret = 0;
2206
2207 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2208 return 0;
2209
2210 ld = tty_ldisc_ref_wait(tty);
2211 if (!ld)
2212 return hung_up_tty_poll(filp, wait);
2213 if (ld->ops->poll)
2214 ret = ld->ops->poll(tty, filp, wait);
2215 tty_ldisc_deref(ld);
2216 return ret;
2217}
2218
2219static int __tty_fasync(int fd, struct file *filp, int on)
2220{
2221 struct tty_struct *tty = file_tty(filp);
2222 unsigned long flags;
2223 int retval = 0;
2224
2225 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2226 goto out;
2227
2228 retval = fasync_helper(fd, filp, on, &tty->fasync);
2229 if (retval <= 0)
2230 goto out;
2231
2232 if (on) {
2233 enum pid_type type;
2234 struct pid *pid;
2235
2236 spin_lock_irqsave(&tty->ctrl.lock, flags);
2237 if (tty->ctrl.pgrp) {
2238 pid = tty->ctrl.pgrp;
2239 type = PIDTYPE_PGID;
2240 } else {
2241 pid = task_pid(current);
2242 type = PIDTYPE_TGID;
2243 }
2244 get_pid(pid);
2245 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
2246 __f_setown(filp, pid, type, 0);
2247 put_pid(pid);
2248 retval = 0;
2249 }
2250out:
2251 return retval;
2252}
2253
2254static int tty_fasync(int fd, struct file *filp, int on)
2255{
2256 struct tty_struct *tty = file_tty(filp);
2257 int retval = -ENOTTY;
2258
2259 tty_lock(tty);
2260 if (!tty_hung_up_p(filp))
2261 retval = __tty_fasync(fd, filp, on);
2262 tty_unlock(tty);
2263
2264 return retval;
2265}
2266
2267static bool tty_legacy_tiocsti __read_mostly = IS_ENABLED(CONFIG_LEGACY_TIOCSTI);
2268/**
2269 * tiocsti - fake input character
2270 * @tty: tty to fake input into
2271 * @p: pointer to character
2272 *
2273 * Fake input to a tty device. Does the necessary locking and input management.
2274 *
2275 * FIXME: does not honour flow control ??
2276 *
2277 * Locking:
2278 * * Called functions take tty_ldiscs_lock
2279 * * current->signal->tty check is safe without locks
2280 */
2281static int tiocsti(struct tty_struct *tty, u8 __user *p)
2282{
2283 struct tty_ldisc *ld;
2284 u8 ch;
2285
2286 if (!tty_legacy_tiocsti && !capable(CAP_SYS_ADMIN))
2287 return -EIO;
2288
2289 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2290 return -EPERM;
2291 if (get_user(ch, p))
2292 return -EFAULT;
2293 tty_audit_tiocsti(tty, ch);
2294 ld = tty_ldisc_ref_wait(tty);
2295 if (!ld)
2296 return -EIO;
2297 tty_buffer_lock_exclusive(tty->port);
2298 if (ld->ops->receive_buf)
2299 ld->ops->receive_buf(tty, &ch, NULL, 1);
2300 tty_buffer_unlock_exclusive(tty->port);
2301 tty_ldisc_deref(ld);
2302 return 0;
2303}
2304
2305/**
2306 * tiocgwinsz - implement window query ioctl
2307 * @tty: tty
2308 * @arg: user buffer for result
2309 *
2310 * Copies the kernel idea of the window size into the user buffer.
2311 *
2312 * Locking: @tty->winsize_mutex is taken to ensure the winsize data is
2313 * consistent.
2314 */
2315static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2316{
2317 int err;
2318
2319 mutex_lock(&tty->winsize_mutex);
2320 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2321 mutex_unlock(&tty->winsize_mutex);
2322
2323 return err ? -EFAULT : 0;
2324}
2325
2326/**
2327 * tty_do_resize - resize event
2328 * @tty: tty being resized
2329 * @ws: new dimensions
2330 *
2331 * Update the termios variables and send the necessary signals to peform a
2332 * terminal resize correctly.
2333 */
2334int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2335{
2336 struct pid *pgrp;
2337
2338 /* Lock the tty */
2339 mutex_lock(&tty->winsize_mutex);
2340 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2341 goto done;
2342
2343 /* Signal the foreground process group */
2344 pgrp = tty_get_pgrp(tty);
2345 if (pgrp)
2346 kill_pgrp(pgrp, SIGWINCH, 1);
2347 put_pid(pgrp);
2348
2349 tty->winsize = *ws;
2350done:
2351 mutex_unlock(&tty->winsize_mutex);
2352 return 0;
2353}
2354EXPORT_SYMBOL(tty_do_resize);
2355
2356/**
2357 * tiocswinsz - implement window size set ioctl
2358 * @tty: tty side of tty
2359 * @arg: user buffer for result
2360 *
2361 * Copies the user idea of the window size to the kernel. Traditionally this is
2362 * just advisory information but for the Linux console it actually has driver
2363 * level meaning and triggers a VC resize.
2364 *
2365 * Locking:
2366 * Driver dependent. The default do_resize method takes the tty termios
2367 * mutex and ctrl.lock. The console takes its own lock then calls into the
2368 * default method.
2369 */
2370static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2371{
2372 struct winsize tmp_ws;
2373
2374 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2375 return -EFAULT;
2376
2377 if (tty->ops->resize)
2378 return tty->ops->resize(tty, &tmp_ws);
2379 else
2380 return tty_do_resize(tty, &tmp_ws);
2381}
2382
2383/**
2384 * tioccons - allow admin to move logical console
2385 * @file: the file to become console
2386 *
2387 * Allow the administrator to move the redirected console device.
2388 *
2389 * Locking: uses redirect_lock to guard the redirect information
2390 */
2391static int tioccons(struct file *file)
2392{
2393 if (!capable(CAP_SYS_ADMIN))
2394 return -EPERM;
2395 if (file->f_op->write_iter == redirected_tty_write) {
2396 struct file *f;
2397
2398 spin_lock(&redirect_lock);
2399 f = redirect;
2400 redirect = NULL;
2401 spin_unlock(&redirect_lock);
2402 if (f)
2403 fput(f);
2404 return 0;
2405 }
2406 if (file->f_op->write_iter != tty_write)
2407 return -ENOTTY;
2408 if (!(file->f_mode & FMODE_WRITE))
2409 return -EBADF;
2410 if (!(file->f_mode & FMODE_CAN_WRITE))
2411 return -EINVAL;
2412 spin_lock(&redirect_lock);
2413 if (redirect) {
2414 spin_unlock(&redirect_lock);
2415 return -EBUSY;
2416 }
2417 redirect = get_file(file);
2418 spin_unlock(&redirect_lock);
2419 return 0;
2420}
2421
2422/**
2423 * tiocsetd - set line discipline
2424 * @tty: tty device
2425 * @p: pointer to user data
2426 *
2427 * Set the line discipline according to user request.
2428 *
2429 * Locking: see tty_set_ldisc(), this function is just a helper
2430 */
2431static int tiocsetd(struct tty_struct *tty, int __user *p)
2432{
2433 int disc;
2434 int ret;
2435
2436 if (get_user(disc, p))
2437 return -EFAULT;
2438
2439 ret = tty_set_ldisc(tty, disc);
2440
2441 return ret;
2442}
2443
2444/**
2445 * tiocgetd - get line discipline
2446 * @tty: tty device
2447 * @p: pointer to user data
2448 *
2449 * Retrieves the line discipline id directly from the ldisc.
2450 *
2451 * Locking: waits for ldisc reference (in case the line discipline is changing
2452 * or the @tty is being hungup)
2453 */
2454static int tiocgetd(struct tty_struct *tty, int __user *p)
2455{
2456 struct tty_ldisc *ld;
2457 int ret;
2458
2459 ld = tty_ldisc_ref_wait(tty);
2460 if (!ld)
2461 return -EIO;
2462 ret = put_user(ld->ops->num, p);
2463 tty_ldisc_deref(ld);
2464 return ret;
2465}
2466
2467/**
2468 * send_break - performed time break
2469 * @tty: device to break on
2470 * @duration: timeout in mS
2471 *
2472 * Perform a timed break on hardware that lacks its own driver level timed
2473 * break functionality.
2474 *
2475 * Locking:
2476 * @tty->atomic_write_lock serializes
2477 */
2478static int send_break(struct tty_struct *tty, unsigned int duration)
2479{
2480 int retval;
2481
2482 if (tty->ops->break_ctl == NULL)
2483 return 0;
2484
2485 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2486 return tty->ops->break_ctl(tty, duration);
2487
2488 /* Do the work ourselves */
2489 if (tty_write_lock(tty, false) < 0)
2490 return -EINTR;
2491
2492 retval = tty->ops->break_ctl(tty, -1);
2493 if (!retval) {
2494 msleep_interruptible(duration);
2495 retval = tty->ops->break_ctl(tty, 0);
2496 } else if (retval == -EOPNOTSUPP) {
2497 /* some drivers can tell only dynamically */
2498 retval = 0;
2499 }
2500 tty_write_unlock(tty);
2501
2502 if (signal_pending(current))
2503 retval = -EINTR;
2504
2505 return retval;
2506}
2507
2508/**
2509 * tty_get_tiocm - get tiocm status register
2510 * @tty: tty device
2511 *
2512 * Obtain the modem status bits from the tty driver if the feature
2513 * is supported.
2514 */
2515int tty_get_tiocm(struct tty_struct *tty)
2516{
2517 int retval = -ENOTTY;
2518
2519 if (tty->ops->tiocmget)
2520 retval = tty->ops->tiocmget(tty);
2521
2522 return retval;
2523}
2524EXPORT_SYMBOL_GPL(tty_get_tiocm);
2525
2526/**
2527 * tty_tiocmget - get modem status
2528 * @tty: tty device
2529 * @p: pointer to result
2530 *
2531 * Obtain the modem status bits from the tty driver if the feature is
2532 * supported. Return -%ENOTTY if it is not available.
2533 *
2534 * Locking: none (up to the driver)
2535 */
2536static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2537{
2538 int retval;
2539
2540 retval = tty_get_tiocm(tty);
2541 if (retval >= 0)
2542 retval = put_user(retval, p);
2543
2544 return retval;
2545}
2546
2547/**
2548 * tty_tiocmset - set modem status
2549 * @tty: tty device
2550 * @cmd: command - clear bits, set bits or set all
2551 * @p: pointer to desired bits
2552 *
2553 * Set the modem status bits from the tty driver if the feature
2554 * is supported. Return -%ENOTTY if it is not available.
2555 *
2556 * Locking: none (up to the driver)
2557 */
2558static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2559 unsigned __user *p)
2560{
2561 int retval;
2562 unsigned int set, clear, val;
2563
2564 if (tty->ops->tiocmset == NULL)
2565 return -ENOTTY;
2566
2567 retval = get_user(val, p);
2568 if (retval)
2569 return retval;
2570 set = clear = 0;
2571 switch (cmd) {
2572 case TIOCMBIS:
2573 set = val;
2574 break;
2575 case TIOCMBIC:
2576 clear = val;
2577 break;
2578 case TIOCMSET:
2579 set = val;
2580 clear = ~val;
2581 break;
2582 }
2583 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2584 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2585 return tty->ops->tiocmset(tty, set, clear);
2586}
2587
2588/**
2589 * tty_get_icount - get tty statistics
2590 * @tty: tty device
2591 * @icount: output parameter
2592 *
2593 * Gets a copy of the @tty's icount statistics.
2594 *
2595 * Locking: none (up to the driver)
2596 */
2597int tty_get_icount(struct tty_struct *tty,
2598 struct serial_icounter_struct *icount)
2599{
2600 memset(icount, 0, sizeof(*icount));
2601
2602 if (tty->ops->get_icount)
2603 return tty->ops->get_icount(tty, icount);
2604 else
2605 return -ENOTTY;
2606}
2607EXPORT_SYMBOL_GPL(tty_get_icount);
2608
2609static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2610{
2611 struct serial_icounter_struct icount;
2612 int retval;
2613
2614 retval = tty_get_icount(tty, &icount);
2615 if (retval != 0)
2616 return retval;
2617
2618 if (copy_to_user(arg, &icount, sizeof(icount)))
2619 return -EFAULT;
2620 return 0;
2621}
2622
2623static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss)
2624{
2625 char comm[TASK_COMM_LEN];
2626 int flags;
2627
2628 flags = ss->flags & ASYNC_DEPRECATED;
2629
2630 if (flags)
2631 pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2632 __func__, get_task_comm(comm, current), flags);
2633
2634 if (!tty->ops->set_serial)
2635 return -ENOTTY;
2636
2637 return tty->ops->set_serial(tty, ss);
2638}
2639
2640static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2641{
2642 struct serial_struct v;
2643
2644 if (copy_from_user(&v, ss, sizeof(*ss)))
2645 return -EFAULT;
2646
2647 return tty_set_serial(tty, &v);
2648}
2649
2650static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2651{
2652 struct serial_struct v;
2653 int err;
2654
2655 memset(&v, 0, sizeof(v));
2656 if (!tty->ops->get_serial)
2657 return -ENOTTY;
2658 err = tty->ops->get_serial(tty, &v);
2659 if (!err && copy_to_user(ss, &v, sizeof(v)))
2660 err = -EFAULT;
2661 return err;
2662}
2663
2664/*
2665 * if pty, return the slave side (real_tty)
2666 * otherwise, return self
2667 */
2668static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2669{
2670 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2671 tty->driver->subtype == PTY_TYPE_MASTER)
2672 tty = tty->link;
2673 return tty;
2674}
2675
2676/*
2677 * Split this up, as gcc can choke on it otherwise..
2678 */
2679long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2680{
2681 struct tty_struct *tty = file_tty(file);
2682 struct tty_struct *real_tty;
2683 void __user *p = (void __user *)arg;
2684 int retval;
2685 struct tty_ldisc *ld;
2686
2687 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2688 return -EINVAL;
2689
2690 real_tty = tty_pair_get_tty(tty);
2691
2692 /*
2693 * Factor out some common prep work
2694 */
2695 switch (cmd) {
2696 case TIOCSETD:
2697 case TIOCSBRK:
2698 case TIOCCBRK:
2699 case TCSBRK:
2700 case TCSBRKP:
2701 retval = tty_check_change(tty);
2702 if (retval)
2703 return retval;
2704 if (cmd != TIOCCBRK) {
2705 tty_wait_until_sent(tty, 0);
2706 if (signal_pending(current))
2707 return -EINTR;
2708 }
2709 break;
2710 }
2711
2712 /*
2713 * Now do the stuff.
2714 */
2715 switch (cmd) {
2716 case TIOCSTI:
2717 return tiocsti(tty, p);
2718 case TIOCGWINSZ:
2719 return tiocgwinsz(real_tty, p);
2720 case TIOCSWINSZ:
2721 return tiocswinsz(real_tty, p);
2722 case TIOCCONS:
2723 return real_tty != tty ? -EINVAL : tioccons(file);
2724 case TIOCEXCL:
2725 set_bit(TTY_EXCLUSIVE, &tty->flags);
2726 return 0;
2727 case TIOCNXCL:
2728 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2729 return 0;
2730 case TIOCGEXCL:
2731 {
2732 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2733
2734 return put_user(excl, (int __user *)p);
2735 }
2736 case TIOCGETD:
2737 return tiocgetd(tty, p);
2738 case TIOCSETD:
2739 return tiocsetd(tty, p);
2740 case TIOCVHANGUP:
2741 if (!capable(CAP_SYS_ADMIN))
2742 return -EPERM;
2743 tty_vhangup(tty);
2744 return 0;
2745 case TIOCGDEV:
2746 {
2747 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2748
2749 return put_user(ret, (unsigned int __user *)p);
2750 }
2751 /*
2752 * Break handling
2753 */
2754 case TIOCSBRK: /* Turn break on, unconditionally */
2755 if (tty->ops->break_ctl)
2756 return tty->ops->break_ctl(tty, -1);
2757 return 0;
2758 case TIOCCBRK: /* Turn break off, unconditionally */
2759 if (tty->ops->break_ctl)
2760 return tty->ops->break_ctl(tty, 0);
2761 return 0;
2762 case TCSBRK: /* SVID version: non-zero arg --> no break */
2763 /* non-zero arg means wait for all output data
2764 * to be sent (performed above) but don't send break.
2765 * This is used by the tcdrain() termios function.
2766 */
2767 if (!arg)
2768 return send_break(tty, 250);
2769 return 0;
2770 case TCSBRKP: /* support for POSIX tcsendbreak() */
2771 return send_break(tty, arg ? arg*100 : 250);
2772
2773 case TIOCMGET:
2774 return tty_tiocmget(tty, p);
2775 case TIOCMSET:
2776 case TIOCMBIC:
2777 case TIOCMBIS:
2778 return tty_tiocmset(tty, cmd, p);
2779 case TIOCGICOUNT:
2780 return tty_tiocgicount(tty, p);
2781 case TCFLSH:
2782 switch (arg) {
2783 case TCIFLUSH:
2784 case TCIOFLUSH:
2785 /* flush tty buffer and allow ldisc to process ioctl */
2786 tty_buffer_flush(tty, NULL);
2787 break;
2788 }
2789 break;
2790 case TIOCSSERIAL:
2791 return tty_tiocsserial(tty, p);
2792 case TIOCGSERIAL:
2793 return tty_tiocgserial(tty, p);
2794 case TIOCGPTPEER:
2795 /* Special because the struct file is needed */
2796 return ptm_open_peer(file, tty, (int)arg);
2797 default:
2798 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2799 if (retval != -ENOIOCTLCMD)
2800 return retval;
2801 }
2802 if (tty->ops->ioctl) {
2803 retval = tty->ops->ioctl(tty, cmd, arg);
2804 if (retval != -ENOIOCTLCMD)
2805 return retval;
2806 }
2807 ld = tty_ldisc_ref_wait(tty);
2808 if (!ld)
2809 return hung_up_tty_ioctl(file, cmd, arg);
2810 retval = -EINVAL;
2811 if (ld->ops->ioctl) {
2812 retval = ld->ops->ioctl(tty, cmd, arg);
2813 if (retval == -ENOIOCTLCMD)
2814 retval = -ENOTTY;
2815 }
2816 tty_ldisc_deref(ld);
2817 return retval;
2818}
2819
2820#ifdef CONFIG_COMPAT
2821
2822struct serial_struct32 {
2823 compat_int_t type;
2824 compat_int_t line;
2825 compat_uint_t port;
2826 compat_int_t irq;
2827 compat_int_t flags;
2828 compat_int_t xmit_fifo_size;
2829 compat_int_t custom_divisor;
2830 compat_int_t baud_base;
2831 unsigned short close_delay;
2832 char io_type;
2833 char reserved_char;
2834 compat_int_t hub6;
2835 unsigned short closing_wait; /* time to wait before closing */
2836 unsigned short closing_wait2; /* no longer used... */
2837 compat_uint_t iomem_base;
2838 unsigned short iomem_reg_shift;
2839 unsigned int port_high;
2840 /* compat_ulong_t iomap_base FIXME */
2841 compat_int_t reserved;
2842};
2843
2844static int compat_tty_tiocsserial(struct tty_struct *tty,
2845 struct serial_struct32 __user *ss)
2846{
2847 struct serial_struct32 v32;
2848 struct serial_struct v;
2849
2850 if (copy_from_user(&v32, ss, sizeof(*ss)))
2851 return -EFAULT;
2852
2853 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2854 v.iomem_base = compat_ptr(v32.iomem_base);
2855 v.iomem_reg_shift = v32.iomem_reg_shift;
2856 v.port_high = v32.port_high;
2857 v.iomap_base = 0;
2858
2859 return tty_set_serial(tty, &v);
2860}
2861
2862static int compat_tty_tiocgserial(struct tty_struct *tty,
2863 struct serial_struct32 __user *ss)
2864{
2865 struct serial_struct32 v32;
2866 struct serial_struct v;
2867 int err;
2868
2869 memset(&v, 0, sizeof(v));
2870 memset(&v32, 0, sizeof(v32));
2871
2872 if (!tty->ops->get_serial)
2873 return -ENOTTY;
2874 err = tty->ops->get_serial(tty, &v);
2875 if (!err) {
2876 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2877 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2878 0xfffffff : ptr_to_compat(v.iomem_base);
2879 v32.iomem_reg_shift = v.iomem_reg_shift;
2880 v32.port_high = v.port_high;
2881 if (copy_to_user(ss, &v32, sizeof(v32)))
2882 err = -EFAULT;
2883 }
2884 return err;
2885}
2886static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2887 unsigned long arg)
2888{
2889 struct tty_struct *tty = file_tty(file);
2890 struct tty_ldisc *ld;
2891 int retval = -ENOIOCTLCMD;
2892
2893 switch (cmd) {
2894 case TIOCOUTQ:
2895 case TIOCSTI:
2896 case TIOCGWINSZ:
2897 case TIOCSWINSZ:
2898 case TIOCGEXCL:
2899 case TIOCGETD:
2900 case TIOCSETD:
2901 case TIOCGDEV:
2902 case TIOCMGET:
2903 case TIOCMSET:
2904 case TIOCMBIC:
2905 case TIOCMBIS:
2906 case TIOCGICOUNT:
2907 case TIOCGPGRP:
2908 case TIOCSPGRP:
2909 case TIOCGSID:
2910 case TIOCSERGETLSR:
2911 case TIOCGRS485:
2912 case TIOCSRS485:
2913#ifdef TIOCGETP
2914 case TIOCGETP:
2915 case TIOCSETP:
2916 case TIOCSETN:
2917#endif
2918#ifdef TIOCGETC
2919 case TIOCGETC:
2920 case TIOCSETC:
2921#endif
2922#ifdef TIOCGLTC
2923 case TIOCGLTC:
2924 case TIOCSLTC:
2925#endif
2926 case TCSETSF:
2927 case TCSETSW:
2928 case TCSETS:
2929 case TCGETS:
2930#ifdef TCGETS2
2931 case TCGETS2:
2932 case TCSETSF2:
2933 case TCSETSW2:
2934 case TCSETS2:
2935#endif
2936 case TCGETA:
2937 case TCSETAF:
2938 case TCSETAW:
2939 case TCSETA:
2940 case TIOCGLCKTRMIOS:
2941 case TIOCSLCKTRMIOS:
2942#ifdef TCGETX
2943 case TCGETX:
2944 case TCSETX:
2945 case TCSETXW:
2946 case TCSETXF:
2947#endif
2948 case TIOCGSOFTCAR:
2949 case TIOCSSOFTCAR:
2950
2951 case PPPIOCGCHAN:
2952 case PPPIOCGUNIT:
2953 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2954 case TIOCCONS:
2955 case TIOCEXCL:
2956 case TIOCNXCL:
2957 case TIOCVHANGUP:
2958 case TIOCSBRK:
2959 case TIOCCBRK:
2960 case TCSBRK:
2961 case TCSBRKP:
2962 case TCFLSH:
2963 case TIOCGPTPEER:
2964 case TIOCNOTTY:
2965 case TIOCSCTTY:
2966 case TCXONC:
2967 case TIOCMIWAIT:
2968 case TIOCSERCONFIG:
2969 return tty_ioctl(file, cmd, arg);
2970 }
2971
2972 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2973 return -EINVAL;
2974
2975 switch (cmd) {
2976 case TIOCSSERIAL:
2977 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2978 case TIOCGSERIAL:
2979 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2980 }
2981 if (tty->ops->compat_ioctl) {
2982 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2983 if (retval != -ENOIOCTLCMD)
2984 return retval;
2985 }
2986
2987 ld = tty_ldisc_ref_wait(tty);
2988 if (!ld)
2989 return hung_up_tty_compat_ioctl(file, cmd, arg);
2990 if (ld->ops->compat_ioctl)
2991 retval = ld->ops->compat_ioctl(tty, cmd, arg);
2992 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2993 retval = ld->ops->ioctl(tty, (unsigned long)compat_ptr(cmd),
2994 arg);
2995 tty_ldisc_deref(ld);
2996
2997 return retval;
2998}
2999#endif
3000
3001static int this_tty(const void *t, struct file *file, unsigned fd)
3002{
3003 if (likely(file->f_op->read_iter != tty_read))
3004 return 0;
3005 return file_tty(file) != t ? 0 : fd + 1;
3006}
3007
3008/*
3009 * This implements the "Secure Attention Key" --- the idea is to
3010 * prevent trojan horses by killing all processes associated with this
3011 * tty when the user hits the "Secure Attention Key". Required for
3012 * super-paranoid applications --- see the Orange Book for more details.
3013 *
3014 * This code could be nicer; ideally it should send a HUP, wait a few
3015 * seconds, then send a INT, and then a KILL signal. But you then
3016 * have to coordinate with the init process, since all processes associated
3017 * with the current tty must be dead before the new getty is allowed
3018 * to spawn.
3019 *
3020 * Now, if it would be correct ;-/ The current code has a nasty hole -
3021 * it doesn't catch files in flight. We may send the descriptor to ourselves
3022 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3023 *
3024 * Nasty bug: do_SAK is being called in interrupt context. This can
3025 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3026 */
3027void __do_SAK(struct tty_struct *tty)
3028{
3029 struct task_struct *g, *p;
3030 struct pid *session;
3031 int i;
3032 unsigned long flags;
3033
3034 spin_lock_irqsave(&tty->ctrl.lock, flags);
3035 session = get_pid(tty->ctrl.session);
3036 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
3037
3038 tty_ldisc_flush(tty);
3039
3040 tty_driver_flush_buffer(tty);
3041
3042 read_lock(&tasklist_lock);
3043 /* Kill the entire session */
3044 do_each_pid_task(session, PIDTYPE_SID, p) {
3045 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3046 task_pid_nr(p), p->comm);
3047 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3048 } while_each_pid_task(session, PIDTYPE_SID, p);
3049
3050 /* Now kill any processes that happen to have the tty open */
3051 for_each_process_thread(g, p) {
3052 if (p->signal->tty == tty) {
3053 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3054 task_pid_nr(p), p->comm);
3055 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
3056 PIDTYPE_SID);
3057 continue;
3058 }
3059 task_lock(p);
3060 i = iterate_fd(p->files, 0, this_tty, tty);
3061 if (i != 0) {
3062 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3063 task_pid_nr(p), p->comm, i - 1);
3064 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
3065 PIDTYPE_SID);
3066 }
3067 task_unlock(p);
3068 }
3069 read_unlock(&tasklist_lock);
3070 put_pid(session);
3071}
3072
3073static void do_SAK_work(struct work_struct *work)
3074{
3075 struct tty_struct *tty =
3076 container_of(work, struct tty_struct, SAK_work);
3077 __do_SAK(tty);
3078}
3079
3080/*
3081 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3082 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3083 * the values which we write to it will be identical to the values which it
3084 * already has. --akpm
3085 */
3086void do_SAK(struct tty_struct *tty)
3087{
3088 if (!tty)
3089 return;
3090 schedule_work(&tty->SAK_work);
3091}
3092EXPORT_SYMBOL(do_SAK);
3093
3094/* Must put_device() after it's unused! */
3095static struct device *tty_get_device(struct tty_struct *tty)
3096{
3097 dev_t devt = tty_devnum(tty);
3098
3099 return class_find_device_by_devt(&tty_class, devt);
3100}
3101
3102
3103/**
3104 * alloc_tty_struct - allocate a new tty
3105 * @driver: driver which will handle the returned tty
3106 * @idx: minor of the tty
3107 *
3108 * This subroutine allocates and initializes a tty structure.
3109 *
3110 * Locking: none - @tty in question is not exposed at this point
3111 */
3112struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3113{
3114 struct tty_struct *tty;
3115
3116 tty = kzalloc(sizeof(*tty), GFP_KERNEL_ACCOUNT);
3117 if (!tty)
3118 return NULL;
3119
3120 kref_init(&tty->kref);
3121 if (tty_ldisc_init(tty)) {
3122 kfree(tty);
3123 return NULL;
3124 }
3125 tty->ctrl.session = NULL;
3126 tty->ctrl.pgrp = NULL;
3127 mutex_init(&tty->legacy_mutex);
3128 mutex_init(&tty->throttle_mutex);
3129 init_rwsem(&tty->termios_rwsem);
3130 mutex_init(&tty->winsize_mutex);
3131 init_ldsem(&tty->ldisc_sem);
3132 init_waitqueue_head(&tty->write_wait);
3133 init_waitqueue_head(&tty->read_wait);
3134 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3135 mutex_init(&tty->atomic_write_lock);
3136 spin_lock_init(&tty->ctrl.lock);
3137 spin_lock_init(&tty->flow.lock);
3138 spin_lock_init(&tty->files_lock);
3139 INIT_LIST_HEAD(&tty->tty_files);
3140 INIT_WORK(&tty->SAK_work, do_SAK_work);
3141
3142 tty->driver = driver;
3143 tty->ops = driver->ops;
3144 tty->index = idx;
3145 tty_line_name(driver, idx, tty->name);
3146 tty->dev = tty_get_device(tty);
3147
3148 return tty;
3149}
3150
3151/**
3152 * tty_put_char - write one character to a tty
3153 * @tty: tty
3154 * @ch: character to write
3155 *
3156 * Write one byte to the @tty using the provided @tty->ops->put_char() method
3157 * if present.
3158 *
3159 * Note: the specific put_char operation in the driver layer may go
3160 * away soon. Don't call it directly, use this method
3161 *
3162 * Return: the number of characters successfully output.
3163 */
3164int tty_put_char(struct tty_struct *tty, u8 ch)
3165{
3166 if (tty->ops->put_char)
3167 return tty->ops->put_char(tty, ch);
3168 return tty->ops->write(tty, &ch, 1);
3169}
3170EXPORT_SYMBOL_GPL(tty_put_char);
3171
3172static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3173 unsigned int index, unsigned int count)
3174{
3175 int err;
3176
3177 /* init here, since reused cdevs cause crashes */
3178 driver->cdevs[index] = cdev_alloc();
3179 if (!driver->cdevs[index])
3180 return -ENOMEM;
3181 driver->cdevs[index]->ops = &tty_fops;
3182 driver->cdevs[index]->owner = driver->owner;
3183 err = cdev_add(driver->cdevs[index], dev, count);
3184 if (err)
3185 kobject_put(&driver->cdevs[index]->kobj);
3186 return err;
3187}
3188
3189/**
3190 * tty_register_device - register a tty device
3191 * @driver: the tty driver that describes the tty device
3192 * @index: the index in the tty driver for this tty device
3193 * @device: a struct device that is associated with this tty device.
3194 * This field is optional, if there is no known struct device
3195 * for this tty device it can be set to NULL safely.
3196 *
3197 * This call is required to be made to register an individual tty device
3198 * if the tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If
3199 * that bit is not set, this function should not be called by a tty
3200 * driver.
3201 *
3202 * Locking: ??
3203 *
3204 * Return: A pointer to the struct device for this tty device (or
3205 * ERR_PTR(-EFOO) on error).
3206 */
3207struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3208 struct device *device)
3209{
3210 return tty_register_device_attr(driver, index, device, NULL, NULL);
3211}
3212EXPORT_SYMBOL(tty_register_device);
3213
3214static void tty_device_create_release(struct device *dev)
3215{
3216 dev_dbg(dev, "releasing...\n");
3217 kfree(dev);
3218}
3219
3220/**
3221 * tty_register_device_attr - register a tty device
3222 * @driver: the tty driver that describes the tty device
3223 * @index: the index in the tty driver for this tty device
3224 * @device: a struct device that is associated with this tty device.
3225 * This field is optional, if there is no known struct device
3226 * for this tty device it can be set to %NULL safely.
3227 * @drvdata: Driver data to be set to device.
3228 * @attr_grp: Attribute group to be set on device.
3229 *
3230 * This call is required to be made to register an individual tty device if the
3231 * tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If that bit is
3232 * not set, this function should not be called by a tty driver.
3233 *
3234 * Locking: ??
3235 *
3236 * Return: A pointer to the struct device for this tty device (or
3237 * ERR_PTR(-EFOO) on error).
3238 */
3239struct device *tty_register_device_attr(struct tty_driver *driver,
3240 unsigned index, struct device *device,
3241 void *drvdata,
3242 const struct attribute_group **attr_grp)
3243{
3244 char name[64];
3245 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3246 struct ktermios *tp;
3247 struct device *dev;
3248 int retval;
3249
3250 if (index >= driver->num) {
3251 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3252 driver->name, index);
3253 return ERR_PTR(-EINVAL);
3254 }
3255
3256 if (driver->type == TTY_DRIVER_TYPE_PTY)
3257 pty_line_name(driver, index, name);
3258 else
3259 tty_line_name(driver, index, name);
3260
3261 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3262 if (!dev)
3263 return ERR_PTR(-ENOMEM);
3264
3265 dev->devt = devt;
3266 dev->class = &tty_class;
3267 dev->parent = device;
3268 dev->release = tty_device_create_release;
3269 dev_set_name(dev, "%s", name);
3270 dev->groups = attr_grp;
3271 dev_set_drvdata(dev, drvdata);
3272
3273 dev_set_uevent_suppress(dev, 1);
3274
3275 retval = device_register(dev);
3276 if (retval)
3277 goto err_put;
3278
3279 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3280 /*
3281 * Free any saved termios data so that the termios state is
3282 * reset when reusing a minor number.
3283 */
3284 tp = driver->termios[index];
3285 if (tp) {
3286 driver->termios[index] = NULL;
3287 kfree(tp);
3288 }
3289
3290 retval = tty_cdev_add(driver, devt, index, 1);
3291 if (retval)
3292 goto err_del;
3293 }
3294
3295 dev_set_uevent_suppress(dev, 0);
3296 kobject_uevent(&dev->kobj, KOBJ_ADD);
3297
3298 return dev;
3299
3300err_del:
3301 device_del(dev);
3302err_put:
3303 put_device(dev);
3304
3305 return ERR_PTR(retval);
3306}
3307EXPORT_SYMBOL_GPL(tty_register_device_attr);
3308
3309/**
3310 * tty_unregister_device - unregister a tty device
3311 * @driver: the tty driver that describes the tty device
3312 * @index: the index in the tty driver for this tty device
3313 *
3314 * If a tty device is registered with a call to tty_register_device() then
3315 * this function must be called when the tty device is gone.
3316 *
3317 * Locking: ??
3318 */
3319void tty_unregister_device(struct tty_driver *driver, unsigned index)
3320{
3321 device_destroy(&tty_class, MKDEV(driver->major, driver->minor_start) + index);
3322 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3323 cdev_del(driver->cdevs[index]);
3324 driver->cdevs[index] = NULL;
3325 }
3326}
3327EXPORT_SYMBOL(tty_unregister_device);
3328
3329/**
3330 * __tty_alloc_driver - allocate tty driver
3331 * @lines: count of lines this driver can handle at most
3332 * @owner: module which is responsible for this driver
3333 * @flags: some of %TTY_DRIVER_ flags, will be set in driver->flags
3334 *
3335 * This should not be called directly, some of the provided macros should be
3336 * used instead. Use IS_ERR() and friends on @retval.
3337 */
3338struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3339 unsigned long flags)
3340{
3341 struct tty_driver *driver;
3342 unsigned int cdevs = 1;
3343 int err;
3344
3345 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3346 return ERR_PTR(-EINVAL);
3347
3348 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
3349 if (!driver)
3350 return ERR_PTR(-ENOMEM);
3351
3352 kref_init(&driver->kref);
3353 driver->num = lines;
3354 driver->owner = owner;
3355 driver->flags = flags;
3356
3357 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3358 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3359 GFP_KERNEL);
3360 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3361 GFP_KERNEL);
3362 if (!driver->ttys || !driver->termios) {
3363 err = -ENOMEM;
3364 goto err_free_all;
3365 }
3366 }
3367
3368 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3369 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3370 GFP_KERNEL);
3371 if (!driver->ports) {
3372 err = -ENOMEM;
3373 goto err_free_all;
3374 }
3375 cdevs = lines;
3376 }
3377
3378 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3379 if (!driver->cdevs) {
3380 err = -ENOMEM;
3381 goto err_free_all;
3382 }
3383
3384 return driver;
3385err_free_all:
3386 kfree(driver->ports);
3387 kfree(driver->ttys);
3388 kfree(driver->termios);
3389 kfree(driver->cdevs);
3390 kfree(driver);
3391 return ERR_PTR(err);
3392}
3393EXPORT_SYMBOL(__tty_alloc_driver);
3394
3395static void destruct_tty_driver(struct kref *kref)
3396{
3397 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3398 int i;
3399 struct ktermios *tp;
3400
3401 if (driver->flags & TTY_DRIVER_INSTALLED) {
3402 for (i = 0; i < driver->num; i++) {
3403 tp = driver->termios[i];
3404 if (tp) {
3405 driver->termios[i] = NULL;
3406 kfree(tp);
3407 }
3408 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3409 tty_unregister_device(driver, i);
3410 }
3411 proc_tty_unregister_driver(driver);
3412 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3413 cdev_del(driver->cdevs[0]);
3414 }
3415 kfree(driver->cdevs);
3416 kfree(driver->ports);
3417 kfree(driver->termios);
3418 kfree(driver->ttys);
3419 kfree(driver);
3420}
3421
3422/**
3423 * tty_driver_kref_put - drop a reference to a tty driver
3424 * @driver: driver of which to drop the reference
3425 *
3426 * The final put will destroy and free up the driver.
3427 */
3428void tty_driver_kref_put(struct tty_driver *driver)
3429{
3430 kref_put(&driver->kref, destruct_tty_driver);
3431}
3432EXPORT_SYMBOL(tty_driver_kref_put);
3433
3434/**
3435 * tty_register_driver - register a tty driver
3436 * @driver: driver to register
3437 *
3438 * Called by a tty driver to register itself.
3439 */
3440int tty_register_driver(struct tty_driver *driver)
3441{
3442 int error;
3443 int i;
3444 dev_t dev;
3445 struct device *d;
3446
3447 if (!driver->major) {
3448 error = alloc_chrdev_region(&dev, driver->minor_start,
3449 driver->num, driver->name);
3450 if (!error) {
3451 driver->major = MAJOR(dev);
3452 driver->minor_start = MINOR(dev);
3453 }
3454 } else {
3455 dev = MKDEV(driver->major, driver->minor_start);
3456 error = register_chrdev_region(dev, driver->num, driver->name);
3457 }
3458 if (error < 0)
3459 goto err;
3460
3461 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3462 error = tty_cdev_add(driver, dev, 0, driver->num);
3463 if (error)
3464 goto err_unreg_char;
3465 }
3466
3467 mutex_lock(&tty_mutex);
3468 list_add(&driver->tty_drivers, &tty_drivers);
3469 mutex_unlock(&tty_mutex);
3470
3471 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3472 for (i = 0; i < driver->num; i++) {
3473 d = tty_register_device(driver, i, NULL);
3474 if (IS_ERR(d)) {
3475 error = PTR_ERR(d);
3476 goto err_unreg_devs;
3477 }
3478 }
3479 }
3480 proc_tty_register_driver(driver);
3481 driver->flags |= TTY_DRIVER_INSTALLED;
3482 return 0;
3483
3484err_unreg_devs:
3485 for (i--; i >= 0; i--)
3486 tty_unregister_device(driver, i);
3487
3488 mutex_lock(&tty_mutex);
3489 list_del(&driver->tty_drivers);
3490 mutex_unlock(&tty_mutex);
3491
3492err_unreg_char:
3493 unregister_chrdev_region(dev, driver->num);
3494err:
3495 return error;
3496}
3497EXPORT_SYMBOL(tty_register_driver);
3498
3499/**
3500 * tty_unregister_driver - unregister a tty driver
3501 * @driver: driver to unregister
3502 *
3503 * Called by a tty driver to unregister itself.
3504 */
3505void tty_unregister_driver(struct tty_driver *driver)
3506{
3507 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3508 driver->num);
3509 mutex_lock(&tty_mutex);
3510 list_del(&driver->tty_drivers);
3511 mutex_unlock(&tty_mutex);
3512}
3513EXPORT_SYMBOL(tty_unregister_driver);
3514
3515dev_t tty_devnum(struct tty_struct *tty)
3516{
3517 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3518}
3519EXPORT_SYMBOL(tty_devnum);
3520
3521void tty_default_fops(struct file_operations *fops)
3522{
3523 *fops = tty_fops;
3524}
3525
3526static char *tty_devnode(const struct device *dev, umode_t *mode)
3527{
3528 if (!mode)
3529 return NULL;
3530 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3531 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3532 *mode = 0666;
3533 return NULL;
3534}
3535
3536const struct class tty_class = {
3537 .name = "tty",
3538 .devnode = tty_devnode,
3539};
3540
3541static int __init tty_class_init(void)
3542{
3543 return class_register(&tty_class);
3544}
3545
3546postcore_initcall(tty_class_init);
3547
3548/* 3/2004 jmc: why do these devices exist? */
3549static struct cdev tty_cdev, console_cdev;
3550
3551static ssize_t show_cons_active(struct device *dev,
3552 struct device_attribute *attr, char *buf)
3553{
3554 struct console *cs[16];
3555 int i = 0;
3556 struct console *c;
3557 ssize_t count = 0;
3558
3559 /*
3560 * Hold the console_list_lock to guarantee that no consoles are
3561 * unregistered until all console processing is complete.
3562 * This also allows safe traversal of the console list and
3563 * race-free reading of @flags.
3564 */
3565 console_list_lock();
3566
3567 for_each_console(c) {
3568 if (!c->device)
3569 continue;
3570 if (!c->write)
3571 continue;
3572 if ((c->flags & CON_ENABLED) == 0)
3573 continue;
3574 cs[i++] = c;
3575 if (i >= ARRAY_SIZE(cs))
3576 break;
3577 }
3578
3579 /*
3580 * Take console_lock to serialize device() callback with
3581 * other console operations. For example, fg_console is
3582 * modified under console_lock when switching vt.
3583 */
3584 console_lock();
3585 while (i--) {
3586 int index = cs[i]->index;
3587 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3588
3589 /* don't resolve tty0 as some programs depend on it */
3590 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3591 count += tty_line_name(drv, index, buf + count);
3592 else
3593 count += sprintf(buf + count, "%s%d",
3594 cs[i]->name, cs[i]->index);
3595
3596 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3597 }
3598 console_unlock();
3599
3600 console_list_unlock();
3601
3602 return count;
3603}
3604static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3605
3606static struct attribute *cons_dev_attrs[] = {
3607 &dev_attr_active.attr,
3608 NULL
3609};
3610
3611ATTRIBUTE_GROUPS(cons_dev);
3612
3613static struct device *consdev;
3614
3615void console_sysfs_notify(void)
3616{
3617 if (consdev)
3618 sysfs_notify(&consdev->kobj, NULL, "active");
3619}
3620
3621static struct ctl_table tty_table[] = {
3622 {
3623 .procname = "legacy_tiocsti",
3624 .data = &tty_legacy_tiocsti,
3625 .maxlen = sizeof(tty_legacy_tiocsti),
3626 .mode = 0644,
3627 .proc_handler = proc_dobool,
3628 },
3629 {
3630 .procname = "ldisc_autoload",
3631 .data = &tty_ldisc_autoload,
3632 .maxlen = sizeof(tty_ldisc_autoload),
3633 .mode = 0644,
3634 .proc_handler = proc_dointvec,
3635 .extra1 = SYSCTL_ZERO,
3636 .extra2 = SYSCTL_ONE,
3637 },
3638};
3639
3640/*
3641 * Ok, now we can initialize the rest of the tty devices and can count
3642 * on memory allocations, interrupts etc..
3643 */
3644int __init tty_init(void)
3645{
3646 register_sysctl_init("dev/tty", tty_table);
3647 cdev_init(&tty_cdev, &tty_fops);
3648 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3649 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3650 panic("Couldn't register /dev/tty driver\n");
3651 device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3652
3653 cdev_init(&console_cdev, &console_fops);
3654 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3655 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3656 panic("Couldn't register /dev/console driver\n");
3657 consdev = device_create_with_groups(&tty_class, NULL,
3658 MKDEV(TTYAUX_MAJOR, 1), NULL,
3659 cons_dev_groups, "console");
3660 if (IS_ERR(consdev))
3661 consdev = NULL;
3662
3663#ifdef CONFIG_VT
3664 vty_init(&console_fops);
3665#endif
3666 return 0;
3667}
1/*
2 * Copyright (C) 1991, 1992 Linus Torvalds
3 */
4
5/*
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
8 *
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
10 *
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
16 *
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
21 *
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
25 *
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
28 * -- TYT, 1/31/92
29 *
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
33 *
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
36 *
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
39 *
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
42 *
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
45 *
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
49 *
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
52 *
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
55 *
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
58 *
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
61 *
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
65 */
66
67#include <linux/types.h>
68#include <linux/major.h>
69#include <linux/errno.h>
70#include <linux/signal.h>
71#include <linux/fcntl.h>
72#include <linux/sched.h>
73#include <linux/interrupt.h>
74#include <linux/tty.h>
75#include <linux/tty_driver.h>
76#include <linux/tty_flip.h>
77#include <linux/devpts_fs.h>
78#include <linux/file.h>
79#include <linux/fdtable.h>
80#include <linux/console.h>
81#include <linux/timer.h>
82#include <linux/ctype.h>
83#include <linux/kd.h>
84#include <linux/mm.h>
85#include <linux/string.h>
86#include <linux/slab.h>
87#include <linux/poll.h>
88#include <linux/proc_fs.h>
89#include <linux/init.h>
90#include <linux/module.h>
91#include <linux/device.h>
92#include <linux/wait.h>
93#include <linux/bitops.h>
94#include <linux/delay.h>
95#include <linux/seq_file.h>
96#include <linux/serial.h>
97#include <linux/ratelimit.h>
98
99#include <linux/uaccess.h>
100
101#include <linux/kbd_kern.h>
102#include <linux/vt_kern.h>
103#include <linux/selection.h>
104
105#include <linux/kmod.h>
106#include <linux/nsproxy.h>
107
108#undef TTY_DEBUG_HANGUP
109
110#define TTY_PARANOIA_CHECK 1
111#define CHECK_TTY_COUNT 1
112
113struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
114 .c_iflag = ICRNL | IXON,
115 .c_oflag = OPOST | ONLCR,
116 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
117 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
118 ECHOCTL | ECHOKE | IEXTEN,
119 .c_cc = INIT_C_CC,
120 .c_ispeed = 38400,
121 .c_ospeed = 38400
122};
123
124EXPORT_SYMBOL(tty_std_termios);
125
126/* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
128 into this file */
129
130LIST_HEAD(tty_drivers); /* linked list of tty drivers */
131
132/* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134DEFINE_MUTEX(tty_mutex);
135EXPORT_SYMBOL(tty_mutex);
136
137/* Spinlock to protect the tty->tty_files list */
138DEFINE_SPINLOCK(tty_files_lock);
139
140static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
141static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
142ssize_t redirected_tty_write(struct file *, const char __user *,
143 size_t, loff_t *);
144static unsigned int tty_poll(struct file *, poll_table *);
145static int tty_open(struct inode *, struct file *);
146long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
147#ifdef CONFIG_COMPAT
148static long tty_compat_ioctl(struct file *file, unsigned int cmd,
149 unsigned long arg);
150#else
151#define tty_compat_ioctl NULL
152#endif
153static int __tty_fasync(int fd, struct file *filp, int on);
154static int tty_fasync(int fd, struct file *filp, int on);
155static void release_tty(struct tty_struct *tty, int idx);
156static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
157static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
158
159/**
160 * alloc_tty_struct - allocate a tty object
161 *
162 * Return a new empty tty structure. The data fields have not
163 * been initialized in any way but has been zeroed
164 *
165 * Locking: none
166 */
167
168struct tty_struct *alloc_tty_struct(void)
169{
170 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
171}
172
173/**
174 * free_tty_struct - free a disused tty
175 * @tty: tty struct to free
176 *
177 * Free the write buffers, tty queue and tty memory itself.
178 *
179 * Locking: none. Must be called after tty is definitely unused
180 */
181
182void free_tty_struct(struct tty_struct *tty)
183{
184 if (!tty)
185 return;
186 if (tty->dev)
187 put_device(tty->dev);
188 kfree(tty->write_buf);
189 tty->magic = 0xDEADDEAD;
190 kfree(tty);
191}
192
193static inline struct tty_struct *file_tty(struct file *file)
194{
195 return ((struct tty_file_private *)file->private_data)->tty;
196}
197
198int tty_alloc_file(struct file *file)
199{
200 struct tty_file_private *priv;
201
202 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
203 if (!priv)
204 return -ENOMEM;
205
206 file->private_data = priv;
207
208 return 0;
209}
210
211/* Associate a new file with the tty structure */
212void tty_add_file(struct tty_struct *tty, struct file *file)
213{
214 struct tty_file_private *priv = file->private_data;
215
216 priv->tty = tty;
217 priv->file = file;
218
219 spin_lock(&tty_files_lock);
220 list_add(&priv->list, &tty->tty_files);
221 spin_unlock(&tty_files_lock);
222}
223
224/**
225 * tty_free_file - free file->private_data
226 *
227 * This shall be used only for fail path handling when tty_add_file was not
228 * called yet.
229 */
230void tty_free_file(struct file *file)
231{
232 struct tty_file_private *priv = file->private_data;
233
234 file->private_data = NULL;
235 kfree(priv);
236}
237
238/* Delete file from its tty */
239static void tty_del_file(struct file *file)
240{
241 struct tty_file_private *priv = file->private_data;
242
243 spin_lock(&tty_files_lock);
244 list_del(&priv->list);
245 spin_unlock(&tty_files_lock);
246 tty_free_file(file);
247}
248
249
250#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
251
252/**
253 * tty_name - return tty naming
254 * @tty: tty structure
255 * @buf: buffer for output
256 *
257 * Convert a tty structure into a name. The name reflects the kernel
258 * naming policy and if udev is in use may not reflect user space
259 *
260 * Locking: none
261 */
262
263char *tty_name(struct tty_struct *tty, char *buf)
264{
265 if (!tty) /* Hmm. NULL pointer. That's fun. */
266 strcpy(buf, "NULL tty");
267 else
268 strcpy(buf, tty->name);
269 return buf;
270}
271
272EXPORT_SYMBOL(tty_name);
273
274int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
275 const char *routine)
276{
277#ifdef TTY_PARANOIA_CHECK
278 if (!tty) {
279 printk(KERN_WARNING
280 "null TTY for (%d:%d) in %s\n",
281 imajor(inode), iminor(inode), routine);
282 return 1;
283 }
284 if (tty->magic != TTY_MAGIC) {
285 printk(KERN_WARNING
286 "bad magic number for tty struct (%d:%d) in %s\n",
287 imajor(inode), iminor(inode), routine);
288 return 1;
289 }
290#endif
291 return 0;
292}
293
294static int check_tty_count(struct tty_struct *tty, const char *routine)
295{
296#ifdef CHECK_TTY_COUNT
297 struct list_head *p;
298 int count = 0;
299
300 spin_lock(&tty_files_lock);
301 list_for_each(p, &tty->tty_files) {
302 count++;
303 }
304 spin_unlock(&tty_files_lock);
305 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
306 tty->driver->subtype == PTY_TYPE_SLAVE &&
307 tty->link && tty->link->count)
308 count++;
309 if (tty->count != count) {
310 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
311 "!= #fd's(%d) in %s\n",
312 tty->name, tty->count, count, routine);
313 return count;
314 }
315#endif
316 return 0;
317}
318
319/**
320 * get_tty_driver - find device of a tty
321 * @dev_t: device identifier
322 * @index: returns the index of the tty
323 *
324 * This routine returns a tty driver structure, given a device number
325 * and also passes back the index number.
326 *
327 * Locking: caller must hold tty_mutex
328 */
329
330static struct tty_driver *get_tty_driver(dev_t device, int *index)
331{
332 struct tty_driver *p;
333
334 list_for_each_entry(p, &tty_drivers, tty_drivers) {
335 dev_t base = MKDEV(p->major, p->minor_start);
336 if (device < base || device >= base + p->num)
337 continue;
338 *index = device - base;
339 return tty_driver_kref_get(p);
340 }
341 return NULL;
342}
343
344#ifdef CONFIG_CONSOLE_POLL
345
346/**
347 * tty_find_polling_driver - find device of a polled tty
348 * @name: name string to match
349 * @line: pointer to resulting tty line nr
350 *
351 * This routine returns a tty driver structure, given a name
352 * and the condition that the tty driver is capable of polled
353 * operation.
354 */
355struct tty_driver *tty_find_polling_driver(char *name, int *line)
356{
357 struct tty_driver *p, *res = NULL;
358 int tty_line = 0;
359 int len;
360 char *str, *stp;
361
362 for (str = name; *str; str++)
363 if ((*str >= '0' && *str <= '9') || *str == ',')
364 break;
365 if (!*str)
366 return NULL;
367
368 len = str - name;
369 tty_line = simple_strtoul(str, &str, 10);
370
371 mutex_lock(&tty_mutex);
372 /* Search through the tty devices to look for a match */
373 list_for_each_entry(p, &tty_drivers, tty_drivers) {
374 if (strncmp(name, p->name, len) != 0)
375 continue;
376 stp = str;
377 if (*stp == ',')
378 stp++;
379 if (*stp == '\0')
380 stp = NULL;
381
382 if (tty_line >= 0 && tty_line < p->num && p->ops &&
383 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
384 res = tty_driver_kref_get(p);
385 *line = tty_line;
386 break;
387 }
388 }
389 mutex_unlock(&tty_mutex);
390
391 return res;
392}
393EXPORT_SYMBOL_GPL(tty_find_polling_driver);
394#endif
395
396/**
397 * tty_check_change - check for POSIX terminal changes
398 * @tty: tty to check
399 *
400 * If we try to write to, or set the state of, a terminal and we're
401 * not in the foreground, send a SIGTTOU. If the signal is blocked or
402 * ignored, go ahead and perform the operation. (POSIX 7.2)
403 *
404 * Locking: ctrl_lock
405 */
406
407int tty_check_change(struct tty_struct *tty)
408{
409 unsigned long flags;
410 int ret = 0;
411
412 if (current->signal->tty != tty)
413 return 0;
414
415 spin_lock_irqsave(&tty->ctrl_lock, flags);
416
417 if (!tty->pgrp) {
418 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
419 goto out_unlock;
420 }
421 if (task_pgrp(current) == tty->pgrp)
422 goto out_unlock;
423 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
424 if (is_ignored(SIGTTOU))
425 goto out;
426 if (is_current_pgrp_orphaned()) {
427 ret = -EIO;
428 goto out;
429 }
430 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
431 set_thread_flag(TIF_SIGPENDING);
432 ret = -ERESTARTSYS;
433out:
434 return ret;
435out_unlock:
436 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
437 return ret;
438}
439
440EXPORT_SYMBOL(tty_check_change);
441
442static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
443 size_t count, loff_t *ppos)
444{
445 return 0;
446}
447
448static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
449 size_t count, loff_t *ppos)
450{
451 return -EIO;
452}
453
454/* No kernel lock held - none needed ;) */
455static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
456{
457 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
458}
459
460static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
461 unsigned long arg)
462{
463 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
464}
465
466static long hung_up_tty_compat_ioctl(struct file *file,
467 unsigned int cmd, unsigned long arg)
468{
469 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
470}
471
472static const struct file_operations tty_fops = {
473 .llseek = no_llseek,
474 .read = tty_read,
475 .write = tty_write,
476 .poll = tty_poll,
477 .unlocked_ioctl = tty_ioctl,
478 .compat_ioctl = tty_compat_ioctl,
479 .open = tty_open,
480 .release = tty_release,
481 .fasync = tty_fasync,
482};
483
484static const struct file_operations console_fops = {
485 .llseek = no_llseek,
486 .read = tty_read,
487 .write = redirected_tty_write,
488 .poll = tty_poll,
489 .unlocked_ioctl = tty_ioctl,
490 .compat_ioctl = tty_compat_ioctl,
491 .open = tty_open,
492 .release = tty_release,
493 .fasync = tty_fasync,
494};
495
496static const struct file_operations hung_up_tty_fops = {
497 .llseek = no_llseek,
498 .read = hung_up_tty_read,
499 .write = hung_up_tty_write,
500 .poll = hung_up_tty_poll,
501 .unlocked_ioctl = hung_up_tty_ioctl,
502 .compat_ioctl = hung_up_tty_compat_ioctl,
503 .release = tty_release,
504};
505
506static DEFINE_SPINLOCK(redirect_lock);
507static struct file *redirect;
508
509/**
510 * tty_wakeup - request more data
511 * @tty: terminal
512 *
513 * Internal and external helper for wakeups of tty. This function
514 * informs the line discipline if present that the driver is ready
515 * to receive more output data.
516 */
517
518void tty_wakeup(struct tty_struct *tty)
519{
520 struct tty_ldisc *ld;
521
522 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
523 ld = tty_ldisc_ref(tty);
524 if (ld) {
525 if (ld->ops->write_wakeup)
526 ld->ops->write_wakeup(tty);
527 tty_ldisc_deref(ld);
528 }
529 }
530 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
531}
532
533EXPORT_SYMBOL_GPL(tty_wakeup);
534
535/**
536 * tty_signal_session_leader - sends SIGHUP to session leader
537 * @tty controlling tty
538 * @exit_session if non-zero, signal all foreground group processes
539 *
540 * Send SIGHUP and SIGCONT to the session leader and its process group.
541 * Optionally, signal all processes in the foreground process group.
542 *
543 * Returns the number of processes in the session with this tty
544 * as their controlling terminal. This value is used to drop
545 * tty references for those processes.
546 */
547static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
548{
549 struct task_struct *p;
550 int refs = 0;
551 struct pid *tty_pgrp = NULL;
552
553 read_lock(&tasklist_lock);
554 if (tty->session) {
555 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
556 spin_lock_irq(&p->sighand->siglock);
557 if (p->signal->tty == tty) {
558 p->signal->tty = NULL;
559 /* We defer the dereferences outside fo
560 the tasklist lock */
561 refs++;
562 }
563 if (!p->signal->leader) {
564 spin_unlock_irq(&p->sighand->siglock);
565 continue;
566 }
567 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
568 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
569 put_pid(p->signal->tty_old_pgrp); /* A noop */
570 spin_lock(&tty->ctrl_lock);
571 tty_pgrp = get_pid(tty->pgrp);
572 if (tty->pgrp)
573 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
574 spin_unlock(&tty->ctrl_lock);
575 spin_unlock_irq(&p->sighand->siglock);
576 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
577 }
578 read_unlock(&tasklist_lock);
579
580 if (tty_pgrp) {
581 if (exit_session)
582 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
583 put_pid(tty_pgrp);
584 }
585
586 return refs;
587}
588
589/**
590 * __tty_hangup - actual handler for hangup events
591 * @work: tty device
592 *
593 * This can be called by a "kworker" kernel thread. That is process
594 * synchronous but doesn't hold any locks, so we need to make sure we
595 * have the appropriate locks for what we're doing.
596 *
597 * The hangup event clears any pending redirections onto the hung up
598 * device. It ensures future writes will error and it does the needed
599 * line discipline hangup and signal delivery. The tty object itself
600 * remains intact.
601 *
602 * Locking:
603 * BTM
604 * redirect lock for undoing redirection
605 * file list lock for manipulating list of ttys
606 * tty_ldiscs_lock from called functions
607 * termios_rwsem resetting termios data
608 * tasklist_lock to walk task list for hangup event
609 * ->siglock to protect ->signal/->sighand
610 */
611static void __tty_hangup(struct tty_struct *tty, int exit_session)
612{
613 struct file *cons_filp = NULL;
614 struct file *filp, *f = NULL;
615 struct tty_file_private *priv;
616 int closecount = 0, n;
617 int refs;
618
619 if (!tty)
620 return;
621
622
623 spin_lock(&redirect_lock);
624 if (redirect && file_tty(redirect) == tty) {
625 f = redirect;
626 redirect = NULL;
627 }
628 spin_unlock(&redirect_lock);
629
630 tty_lock(tty);
631
632 if (test_bit(TTY_HUPPED, &tty->flags)) {
633 tty_unlock(tty);
634 return;
635 }
636
637 /* some functions below drop BTM, so we need this bit */
638 set_bit(TTY_HUPPING, &tty->flags);
639
640 /* inuse_filps is protected by the single tty lock,
641 this really needs to change if we want to flush the
642 workqueue with the lock held */
643 check_tty_count(tty, "tty_hangup");
644
645 spin_lock(&tty_files_lock);
646 /* This breaks for file handles being sent over AF_UNIX sockets ? */
647 list_for_each_entry(priv, &tty->tty_files, list) {
648 filp = priv->file;
649 if (filp->f_op->write == redirected_tty_write)
650 cons_filp = filp;
651 if (filp->f_op->write != tty_write)
652 continue;
653 closecount++;
654 __tty_fasync(-1, filp, 0); /* can't block */
655 filp->f_op = &hung_up_tty_fops;
656 }
657 spin_unlock(&tty_files_lock);
658
659 refs = tty_signal_session_leader(tty, exit_session);
660 /* Account for the p->signal references we killed */
661 while (refs--)
662 tty_kref_put(tty);
663
664 /*
665 * it drops BTM and thus races with reopen
666 * we protect the race by TTY_HUPPING
667 */
668 tty_ldisc_hangup(tty);
669
670 spin_lock_irq(&tty->ctrl_lock);
671 clear_bit(TTY_THROTTLED, &tty->flags);
672 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
673 put_pid(tty->session);
674 put_pid(tty->pgrp);
675 tty->session = NULL;
676 tty->pgrp = NULL;
677 tty->ctrl_status = 0;
678 spin_unlock_irq(&tty->ctrl_lock);
679
680 /*
681 * If one of the devices matches a console pointer, we
682 * cannot just call hangup() because that will cause
683 * tty->count and state->count to go out of sync.
684 * So we just call close() the right number of times.
685 */
686 if (cons_filp) {
687 if (tty->ops->close)
688 for (n = 0; n < closecount; n++)
689 tty->ops->close(tty, cons_filp);
690 } else if (tty->ops->hangup)
691 (tty->ops->hangup)(tty);
692 /*
693 * We don't want to have driver/ldisc interactions beyond
694 * the ones we did here. The driver layer expects no
695 * calls after ->hangup() from the ldisc side. However we
696 * can't yet guarantee all that.
697 */
698 set_bit(TTY_HUPPED, &tty->flags);
699 clear_bit(TTY_HUPPING, &tty->flags);
700
701 tty_unlock(tty);
702
703 if (f)
704 fput(f);
705}
706
707static void do_tty_hangup(struct work_struct *work)
708{
709 struct tty_struct *tty =
710 container_of(work, struct tty_struct, hangup_work);
711
712 __tty_hangup(tty, 0);
713}
714
715/**
716 * tty_hangup - trigger a hangup event
717 * @tty: tty to hangup
718 *
719 * A carrier loss (virtual or otherwise) has occurred on this like
720 * schedule a hangup sequence to run after this event.
721 */
722
723void tty_hangup(struct tty_struct *tty)
724{
725#ifdef TTY_DEBUG_HANGUP
726 char buf[64];
727 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
728#endif
729 schedule_work(&tty->hangup_work);
730}
731
732EXPORT_SYMBOL(tty_hangup);
733
734/**
735 * tty_vhangup - process vhangup
736 * @tty: tty to hangup
737 *
738 * The user has asked via system call for the terminal to be hung up.
739 * We do this synchronously so that when the syscall returns the process
740 * is complete. That guarantee is necessary for security reasons.
741 */
742
743void tty_vhangup(struct tty_struct *tty)
744{
745#ifdef TTY_DEBUG_HANGUP
746 char buf[64];
747
748 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
749#endif
750 __tty_hangup(tty, 0);
751}
752
753EXPORT_SYMBOL(tty_vhangup);
754
755
756/**
757 * tty_vhangup_self - process vhangup for own ctty
758 *
759 * Perform a vhangup on the current controlling tty
760 */
761
762void tty_vhangup_self(void)
763{
764 struct tty_struct *tty;
765
766 tty = get_current_tty();
767 if (tty) {
768 tty_vhangup(tty);
769 tty_kref_put(tty);
770 }
771}
772
773/**
774 * tty_vhangup_session - hangup session leader exit
775 * @tty: tty to hangup
776 *
777 * The session leader is exiting and hanging up its controlling terminal.
778 * Every process in the foreground process group is signalled SIGHUP.
779 *
780 * We do this synchronously so that when the syscall returns the process
781 * is complete. That guarantee is necessary for security reasons.
782 */
783
784static void tty_vhangup_session(struct tty_struct *tty)
785{
786#ifdef TTY_DEBUG_HANGUP
787 char buf[64];
788
789 printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
790#endif
791 __tty_hangup(tty, 1);
792}
793
794/**
795 * tty_hung_up_p - was tty hung up
796 * @filp: file pointer of tty
797 *
798 * Return true if the tty has been subject to a vhangup or a carrier
799 * loss
800 */
801
802int tty_hung_up_p(struct file *filp)
803{
804 return (filp->f_op == &hung_up_tty_fops);
805}
806
807EXPORT_SYMBOL(tty_hung_up_p);
808
809static void session_clear_tty(struct pid *session)
810{
811 struct task_struct *p;
812 do_each_pid_task(session, PIDTYPE_SID, p) {
813 proc_clear_tty(p);
814 } while_each_pid_task(session, PIDTYPE_SID, p);
815}
816
817/**
818 * disassociate_ctty - disconnect controlling tty
819 * @on_exit: true if exiting so need to "hang up" the session
820 *
821 * This function is typically called only by the session leader, when
822 * it wants to disassociate itself from its controlling tty.
823 *
824 * It performs the following functions:
825 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
826 * (2) Clears the tty from being controlling the session
827 * (3) Clears the controlling tty for all processes in the
828 * session group.
829 *
830 * The argument on_exit is set to 1 if called when a process is
831 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
832 *
833 * Locking:
834 * BTM is taken for hysterical raisins, and held when
835 * called from no_tty().
836 * tty_mutex is taken to protect tty
837 * ->siglock is taken to protect ->signal/->sighand
838 * tasklist_lock is taken to walk process list for sessions
839 * ->siglock is taken to protect ->signal/->sighand
840 */
841
842void disassociate_ctty(int on_exit)
843{
844 struct tty_struct *tty;
845
846 if (!current->signal->leader)
847 return;
848
849 tty = get_current_tty();
850 if (tty) {
851 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
852 tty_vhangup_session(tty);
853 } else {
854 struct pid *tty_pgrp = tty_get_pgrp(tty);
855 if (tty_pgrp) {
856 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
857 if (!on_exit)
858 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
859 put_pid(tty_pgrp);
860 }
861 }
862 tty_kref_put(tty);
863
864 } else if (on_exit) {
865 struct pid *old_pgrp;
866 spin_lock_irq(¤t->sighand->siglock);
867 old_pgrp = current->signal->tty_old_pgrp;
868 current->signal->tty_old_pgrp = NULL;
869 spin_unlock_irq(¤t->sighand->siglock);
870 if (old_pgrp) {
871 kill_pgrp(old_pgrp, SIGHUP, on_exit);
872 kill_pgrp(old_pgrp, SIGCONT, on_exit);
873 put_pid(old_pgrp);
874 }
875 return;
876 }
877
878 spin_lock_irq(¤t->sighand->siglock);
879 put_pid(current->signal->tty_old_pgrp);
880 current->signal->tty_old_pgrp = NULL;
881
882 tty = tty_kref_get(current->signal->tty);
883 if (tty) {
884 unsigned long flags;
885 spin_lock_irqsave(&tty->ctrl_lock, flags);
886 put_pid(tty->session);
887 put_pid(tty->pgrp);
888 tty->session = NULL;
889 tty->pgrp = NULL;
890 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
891 tty_kref_put(tty);
892 } else {
893#ifdef TTY_DEBUG_HANGUP
894 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
895 " = NULL", tty);
896#endif
897 }
898
899 spin_unlock_irq(¤t->sighand->siglock);
900 /* Now clear signal->tty under the lock */
901 read_lock(&tasklist_lock);
902 session_clear_tty(task_session(current));
903 read_unlock(&tasklist_lock);
904}
905
906/**
907 *
908 * no_tty - Ensure the current process does not have a controlling tty
909 */
910void no_tty(void)
911{
912 /* FIXME: Review locking here. The tty_lock never covered any race
913 between a new association and proc_clear_tty but possible we need
914 to protect against this anyway */
915 struct task_struct *tsk = current;
916 disassociate_ctty(0);
917 proc_clear_tty(tsk);
918}
919
920
921/**
922 * stop_tty - propagate flow control
923 * @tty: tty to stop
924 *
925 * Perform flow control to the driver. For PTY/TTY pairs we
926 * must also propagate the TIOCKPKT status. May be called
927 * on an already stopped device and will not re-call the driver
928 * method.
929 *
930 * This functionality is used by both the line disciplines for
931 * halting incoming flow and by the driver. It may therefore be
932 * called from any context, may be under the tty atomic_write_lock
933 * but not always.
934 *
935 * Locking:
936 * Uses the tty control lock internally
937 */
938
939void stop_tty(struct tty_struct *tty)
940{
941 unsigned long flags;
942 spin_lock_irqsave(&tty->ctrl_lock, flags);
943 if (tty->stopped) {
944 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
945 return;
946 }
947 tty->stopped = 1;
948 if (tty->link && tty->link->packet) {
949 tty->ctrl_status &= ~TIOCPKT_START;
950 tty->ctrl_status |= TIOCPKT_STOP;
951 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
952 }
953 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
954 if (tty->ops->stop)
955 (tty->ops->stop)(tty);
956}
957
958EXPORT_SYMBOL(stop_tty);
959
960/**
961 * start_tty - propagate flow control
962 * @tty: tty to start
963 *
964 * Start a tty that has been stopped if at all possible. Perform
965 * any necessary wakeups and propagate the TIOCPKT status. If this
966 * is the tty was previous stopped and is being started then the
967 * driver start method is invoked and the line discipline woken.
968 *
969 * Locking:
970 * ctrl_lock
971 */
972
973void start_tty(struct tty_struct *tty)
974{
975 unsigned long flags;
976 spin_lock_irqsave(&tty->ctrl_lock, flags);
977 if (!tty->stopped || tty->flow_stopped) {
978 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
979 return;
980 }
981 tty->stopped = 0;
982 if (tty->link && tty->link->packet) {
983 tty->ctrl_status &= ~TIOCPKT_STOP;
984 tty->ctrl_status |= TIOCPKT_START;
985 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
986 }
987 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
988 if (tty->ops->start)
989 (tty->ops->start)(tty);
990 /* If we have a running line discipline it may need kicking */
991 tty_wakeup(tty);
992}
993
994EXPORT_SYMBOL(start_tty);
995
996/* We limit tty time update visibility to every 8 seconds or so. */
997static void tty_update_time(struct timespec *time)
998{
999 unsigned long sec = get_seconds() & ~7;
1000 if ((long)(sec - time->tv_sec) > 0)
1001 time->tv_sec = sec;
1002}
1003
1004/**
1005 * tty_read - read method for tty device files
1006 * @file: pointer to tty file
1007 * @buf: user buffer
1008 * @count: size of user buffer
1009 * @ppos: unused
1010 *
1011 * Perform the read system call function on this terminal device. Checks
1012 * for hung up devices before calling the line discipline method.
1013 *
1014 * Locking:
1015 * Locks the line discipline internally while needed. Multiple
1016 * read calls may be outstanding in parallel.
1017 */
1018
1019static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1020 loff_t *ppos)
1021{
1022 int i;
1023 struct inode *inode = file_inode(file);
1024 struct tty_struct *tty = file_tty(file);
1025 struct tty_ldisc *ld;
1026
1027 if (tty_paranoia_check(tty, inode, "tty_read"))
1028 return -EIO;
1029 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1030 return -EIO;
1031
1032 /* We want to wait for the line discipline to sort out in this
1033 situation */
1034 ld = tty_ldisc_ref_wait(tty);
1035 if (ld->ops->read)
1036 i = (ld->ops->read)(tty, file, buf, count);
1037 else
1038 i = -EIO;
1039 tty_ldisc_deref(ld);
1040
1041 if (i > 0)
1042 tty_update_time(&inode->i_atime);
1043
1044 return i;
1045}
1046
1047void tty_write_unlock(struct tty_struct *tty)
1048 __releases(&tty->atomic_write_lock)
1049{
1050 mutex_unlock(&tty->atomic_write_lock);
1051 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1052}
1053
1054int tty_write_lock(struct tty_struct *tty, int ndelay)
1055 __acquires(&tty->atomic_write_lock)
1056{
1057 if (!mutex_trylock(&tty->atomic_write_lock)) {
1058 if (ndelay)
1059 return -EAGAIN;
1060 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1061 return -ERESTARTSYS;
1062 }
1063 return 0;
1064}
1065
1066/*
1067 * Split writes up in sane blocksizes to avoid
1068 * denial-of-service type attacks
1069 */
1070static inline ssize_t do_tty_write(
1071 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1072 struct tty_struct *tty,
1073 struct file *file,
1074 const char __user *buf,
1075 size_t count)
1076{
1077 ssize_t ret, written = 0;
1078 unsigned int chunk;
1079
1080 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1081 if (ret < 0)
1082 return ret;
1083
1084 /*
1085 * We chunk up writes into a temporary buffer. This
1086 * simplifies low-level drivers immensely, since they
1087 * don't have locking issues and user mode accesses.
1088 *
1089 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1090 * big chunk-size..
1091 *
1092 * The default chunk-size is 2kB, because the NTTY
1093 * layer has problems with bigger chunks. It will
1094 * claim to be able to handle more characters than
1095 * it actually does.
1096 *
1097 * FIXME: This can probably go away now except that 64K chunks
1098 * are too likely to fail unless switched to vmalloc...
1099 */
1100 chunk = 2048;
1101 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1102 chunk = 65536;
1103 if (count < chunk)
1104 chunk = count;
1105
1106 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1107 if (tty->write_cnt < chunk) {
1108 unsigned char *buf_chunk;
1109
1110 if (chunk < 1024)
1111 chunk = 1024;
1112
1113 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1114 if (!buf_chunk) {
1115 ret = -ENOMEM;
1116 goto out;
1117 }
1118 kfree(tty->write_buf);
1119 tty->write_cnt = chunk;
1120 tty->write_buf = buf_chunk;
1121 }
1122
1123 /* Do the write .. */
1124 for (;;) {
1125 size_t size = count;
1126 if (size > chunk)
1127 size = chunk;
1128 ret = -EFAULT;
1129 if (copy_from_user(tty->write_buf, buf, size))
1130 break;
1131 ret = write(tty, file, tty->write_buf, size);
1132 if (ret <= 0)
1133 break;
1134 written += ret;
1135 buf += ret;
1136 count -= ret;
1137 if (!count)
1138 break;
1139 ret = -ERESTARTSYS;
1140 if (signal_pending(current))
1141 break;
1142 cond_resched();
1143 }
1144 if (written) {
1145 tty_update_time(&file_inode(file)->i_mtime);
1146 ret = written;
1147 }
1148out:
1149 tty_write_unlock(tty);
1150 return ret;
1151}
1152
1153/**
1154 * tty_write_message - write a message to a certain tty, not just the console.
1155 * @tty: the destination tty_struct
1156 * @msg: the message to write
1157 *
1158 * This is used for messages that need to be redirected to a specific tty.
1159 * We don't put it into the syslog queue right now maybe in the future if
1160 * really needed.
1161 *
1162 * We must still hold the BTM and test the CLOSING flag for the moment.
1163 */
1164
1165void tty_write_message(struct tty_struct *tty, char *msg)
1166{
1167 if (tty) {
1168 mutex_lock(&tty->atomic_write_lock);
1169 tty_lock(tty);
1170 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1171 tty_unlock(tty);
1172 tty->ops->write(tty, msg, strlen(msg));
1173 } else
1174 tty_unlock(tty);
1175 tty_write_unlock(tty);
1176 }
1177 return;
1178}
1179
1180
1181/**
1182 * tty_write - write method for tty device file
1183 * @file: tty file pointer
1184 * @buf: user data to write
1185 * @count: bytes to write
1186 * @ppos: unused
1187 *
1188 * Write data to a tty device via the line discipline.
1189 *
1190 * Locking:
1191 * Locks the line discipline as required
1192 * Writes to the tty driver are serialized by the atomic_write_lock
1193 * and are then processed in chunks to the device. The line discipline
1194 * write method will not be invoked in parallel for each device.
1195 */
1196
1197static ssize_t tty_write(struct file *file, const char __user *buf,
1198 size_t count, loff_t *ppos)
1199{
1200 struct tty_struct *tty = file_tty(file);
1201 struct tty_ldisc *ld;
1202 ssize_t ret;
1203
1204 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1205 return -EIO;
1206 if (!tty || !tty->ops->write ||
1207 (test_bit(TTY_IO_ERROR, &tty->flags)))
1208 return -EIO;
1209 /* Short term debug to catch buggy drivers */
1210 if (tty->ops->write_room == NULL)
1211 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1212 tty->driver->name);
1213 ld = tty_ldisc_ref_wait(tty);
1214 if (!ld->ops->write)
1215 ret = -EIO;
1216 else
1217 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1218 tty_ldisc_deref(ld);
1219 return ret;
1220}
1221
1222ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1223 size_t count, loff_t *ppos)
1224{
1225 struct file *p = NULL;
1226
1227 spin_lock(&redirect_lock);
1228 if (redirect)
1229 p = get_file(redirect);
1230 spin_unlock(&redirect_lock);
1231
1232 if (p) {
1233 ssize_t res;
1234 res = vfs_write(p, buf, count, &p->f_pos);
1235 fput(p);
1236 return res;
1237 }
1238 return tty_write(file, buf, count, ppos);
1239}
1240
1241static char ptychar[] = "pqrstuvwxyzabcde";
1242
1243/**
1244 * pty_line_name - generate name for a pty
1245 * @driver: the tty driver in use
1246 * @index: the minor number
1247 * @p: output buffer of at least 6 bytes
1248 *
1249 * Generate a name from a driver reference and write it to the output
1250 * buffer.
1251 *
1252 * Locking: None
1253 */
1254static void pty_line_name(struct tty_driver *driver, int index, char *p)
1255{
1256 int i = index + driver->name_base;
1257 /* ->name is initialized to "ttyp", but "tty" is expected */
1258 sprintf(p, "%s%c%x",
1259 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1260 ptychar[i >> 4 & 0xf], i & 0xf);
1261}
1262
1263/**
1264 * tty_line_name - generate name for a tty
1265 * @driver: the tty driver in use
1266 * @index: the minor number
1267 * @p: output buffer of at least 7 bytes
1268 *
1269 * Generate a name from a driver reference and write it to the output
1270 * buffer.
1271 *
1272 * Locking: None
1273 */
1274static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1275{
1276 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1277 return sprintf(p, "%s", driver->name);
1278 else
1279 return sprintf(p, "%s%d", driver->name,
1280 index + driver->name_base);
1281}
1282
1283/**
1284 * tty_driver_lookup_tty() - find an existing tty, if any
1285 * @driver: the driver for the tty
1286 * @idx: the minor number
1287 *
1288 * Return the tty, if found or ERR_PTR() otherwise.
1289 *
1290 * Locking: tty_mutex must be held. If tty is found, the mutex must
1291 * be held until the 'fast-open' is also done. Will change once we
1292 * have refcounting in the driver and per driver locking
1293 */
1294static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1295 struct inode *inode, int idx)
1296{
1297 if (driver->ops->lookup)
1298 return driver->ops->lookup(driver, inode, idx);
1299
1300 return driver->ttys[idx];
1301}
1302
1303/**
1304 * tty_init_termios - helper for termios setup
1305 * @tty: the tty to set up
1306 *
1307 * Initialise the termios structures for this tty. Thus runs under
1308 * the tty_mutex currently so we can be relaxed about ordering.
1309 */
1310
1311int tty_init_termios(struct tty_struct *tty)
1312{
1313 struct ktermios *tp;
1314 int idx = tty->index;
1315
1316 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1317 tty->termios = tty->driver->init_termios;
1318 else {
1319 /* Check for lazy saved data */
1320 tp = tty->driver->termios[idx];
1321 if (tp != NULL)
1322 tty->termios = *tp;
1323 else
1324 tty->termios = tty->driver->init_termios;
1325 }
1326 /* Compatibility until drivers always set this */
1327 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1328 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1329 return 0;
1330}
1331EXPORT_SYMBOL_GPL(tty_init_termios);
1332
1333int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1334{
1335 int ret = tty_init_termios(tty);
1336 if (ret)
1337 return ret;
1338
1339 tty_driver_kref_get(driver);
1340 tty->count++;
1341 driver->ttys[tty->index] = tty;
1342 return 0;
1343}
1344EXPORT_SYMBOL_GPL(tty_standard_install);
1345
1346/**
1347 * tty_driver_install_tty() - install a tty entry in the driver
1348 * @driver: the driver for the tty
1349 * @tty: the tty
1350 *
1351 * Install a tty object into the driver tables. The tty->index field
1352 * will be set by the time this is called. This method is responsible
1353 * for ensuring any need additional structures are allocated and
1354 * configured.
1355 *
1356 * Locking: tty_mutex for now
1357 */
1358static int tty_driver_install_tty(struct tty_driver *driver,
1359 struct tty_struct *tty)
1360{
1361 return driver->ops->install ? driver->ops->install(driver, tty) :
1362 tty_standard_install(driver, tty);
1363}
1364
1365/**
1366 * tty_driver_remove_tty() - remove a tty from the driver tables
1367 * @driver: the driver for the tty
1368 * @idx: the minor number
1369 *
1370 * Remvoe a tty object from the driver tables. The tty->index field
1371 * will be set by the time this is called.
1372 *
1373 * Locking: tty_mutex for now
1374 */
1375void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1376{
1377 if (driver->ops->remove)
1378 driver->ops->remove(driver, tty);
1379 else
1380 driver->ttys[tty->index] = NULL;
1381}
1382
1383/*
1384 * tty_reopen() - fast re-open of an open tty
1385 * @tty - the tty to open
1386 *
1387 * Return 0 on success, -errno on error.
1388 *
1389 * Locking: tty_mutex must be held from the time the tty was found
1390 * till this open completes.
1391 */
1392static int tty_reopen(struct tty_struct *tty)
1393{
1394 struct tty_driver *driver = tty->driver;
1395
1396 if (test_bit(TTY_CLOSING, &tty->flags) ||
1397 test_bit(TTY_HUPPING, &tty->flags))
1398 return -EIO;
1399
1400 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1401 driver->subtype == PTY_TYPE_MASTER) {
1402 /*
1403 * special case for PTY masters: only one open permitted,
1404 * and the slave side open count is incremented as well.
1405 */
1406 if (tty->count)
1407 return -EIO;
1408
1409 tty->link->count++;
1410 }
1411 tty->count++;
1412
1413 WARN_ON(!tty->ldisc);
1414
1415 return 0;
1416}
1417
1418/**
1419 * tty_init_dev - initialise a tty device
1420 * @driver: tty driver we are opening a device on
1421 * @idx: device index
1422 * @ret_tty: returned tty structure
1423 *
1424 * Prepare a tty device. This may not be a "new" clean device but
1425 * could also be an active device. The pty drivers require special
1426 * handling because of this.
1427 *
1428 * Locking:
1429 * The function is called under the tty_mutex, which
1430 * protects us from the tty struct or driver itself going away.
1431 *
1432 * On exit the tty device has the line discipline attached and
1433 * a reference count of 1. If a pair was created for pty/tty use
1434 * and the other was a pty master then it too has a reference count of 1.
1435 *
1436 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1437 * failed open. The new code protects the open with a mutex, so it's
1438 * really quite straightforward. The mutex locking can probably be
1439 * relaxed for the (most common) case of reopening a tty.
1440 */
1441
1442struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1443{
1444 struct tty_struct *tty;
1445 int retval;
1446
1447 /*
1448 * First time open is complex, especially for PTY devices.
1449 * This code guarantees that either everything succeeds and the
1450 * TTY is ready for operation, or else the table slots are vacated
1451 * and the allocated memory released. (Except that the termios
1452 * and locked termios may be retained.)
1453 */
1454
1455 if (!try_module_get(driver->owner))
1456 return ERR_PTR(-ENODEV);
1457
1458 tty = alloc_tty_struct();
1459 if (!tty) {
1460 retval = -ENOMEM;
1461 goto err_module_put;
1462 }
1463 initialize_tty_struct(tty, driver, idx);
1464
1465 tty_lock(tty);
1466 retval = tty_driver_install_tty(driver, tty);
1467 if (retval < 0)
1468 goto err_deinit_tty;
1469
1470 if (!tty->port)
1471 tty->port = driver->ports[idx];
1472
1473 WARN_RATELIMIT(!tty->port,
1474 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1475 __func__, tty->driver->name);
1476
1477 tty->port->itty = tty;
1478
1479 /*
1480 * Structures all installed ... call the ldisc open routines.
1481 * If we fail here just call release_tty to clean up. No need
1482 * to decrement the use counts, as release_tty doesn't care.
1483 */
1484 retval = tty_ldisc_setup(tty, tty->link);
1485 if (retval)
1486 goto err_release_tty;
1487 /* Return the tty locked so that it cannot vanish under the caller */
1488 return tty;
1489
1490err_deinit_tty:
1491 tty_unlock(tty);
1492 deinitialize_tty_struct(tty);
1493 free_tty_struct(tty);
1494err_module_put:
1495 module_put(driver->owner);
1496 return ERR_PTR(retval);
1497
1498 /* call the tty release_tty routine to clean out this slot */
1499err_release_tty:
1500 tty_unlock(tty);
1501 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1502 "clearing slot %d\n", idx);
1503 release_tty(tty, idx);
1504 return ERR_PTR(retval);
1505}
1506
1507void tty_free_termios(struct tty_struct *tty)
1508{
1509 struct ktermios *tp;
1510 int idx = tty->index;
1511
1512 /* If the port is going to reset then it has no termios to save */
1513 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1514 return;
1515
1516 /* Stash the termios data */
1517 tp = tty->driver->termios[idx];
1518 if (tp == NULL) {
1519 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1520 if (tp == NULL) {
1521 pr_warn("tty: no memory to save termios state.\n");
1522 return;
1523 }
1524 tty->driver->termios[idx] = tp;
1525 }
1526 *tp = tty->termios;
1527}
1528EXPORT_SYMBOL(tty_free_termios);
1529
1530/**
1531 * tty_flush_works - flush all works of a tty
1532 * @tty: tty device to flush works for
1533 *
1534 * Sync flush all works belonging to @tty.
1535 */
1536static void tty_flush_works(struct tty_struct *tty)
1537{
1538 flush_work(&tty->SAK_work);
1539 flush_work(&tty->hangup_work);
1540}
1541
1542/**
1543 * release_one_tty - release tty structure memory
1544 * @kref: kref of tty we are obliterating
1545 *
1546 * Releases memory associated with a tty structure, and clears out the
1547 * driver table slots. This function is called when a device is no longer
1548 * in use. It also gets called when setup of a device fails.
1549 *
1550 * Locking:
1551 * takes the file list lock internally when working on the list
1552 * of ttys that the driver keeps.
1553 *
1554 * This method gets called from a work queue so that the driver private
1555 * cleanup ops can sleep (needed for USB at least)
1556 */
1557static void release_one_tty(struct work_struct *work)
1558{
1559 struct tty_struct *tty =
1560 container_of(work, struct tty_struct, hangup_work);
1561 struct tty_driver *driver = tty->driver;
1562
1563 if (tty->ops->cleanup)
1564 tty->ops->cleanup(tty);
1565
1566 tty->magic = 0;
1567 tty_driver_kref_put(driver);
1568 module_put(driver->owner);
1569
1570 spin_lock(&tty_files_lock);
1571 list_del_init(&tty->tty_files);
1572 spin_unlock(&tty_files_lock);
1573
1574 put_pid(tty->pgrp);
1575 put_pid(tty->session);
1576 free_tty_struct(tty);
1577}
1578
1579static void queue_release_one_tty(struct kref *kref)
1580{
1581 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1582
1583 /* The hangup queue is now free so we can reuse it rather than
1584 waste a chunk of memory for each port */
1585 INIT_WORK(&tty->hangup_work, release_one_tty);
1586 schedule_work(&tty->hangup_work);
1587}
1588
1589/**
1590 * tty_kref_put - release a tty kref
1591 * @tty: tty device
1592 *
1593 * Release a reference to a tty device and if need be let the kref
1594 * layer destruct the object for us
1595 */
1596
1597void tty_kref_put(struct tty_struct *tty)
1598{
1599 if (tty)
1600 kref_put(&tty->kref, queue_release_one_tty);
1601}
1602EXPORT_SYMBOL(tty_kref_put);
1603
1604/**
1605 * release_tty - release tty structure memory
1606 *
1607 * Release both @tty and a possible linked partner (think pty pair),
1608 * and decrement the refcount of the backing module.
1609 *
1610 * Locking:
1611 * tty_mutex
1612 * takes the file list lock internally when working on the list
1613 * of ttys that the driver keeps.
1614 *
1615 */
1616static void release_tty(struct tty_struct *tty, int idx)
1617{
1618 /* This should always be true but check for the moment */
1619 WARN_ON(tty->index != idx);
1620 WARN_ON(!mutex_is_locked(&tty_mutex));
1621 if (tty->ops->shutdown)
1622 tty->ops->shutdown(tty);
1623 tty_free_termios(tty);
1624 tty_driver_remove_tty(tty->driver, tty);
1625 tty->port->itty = NULL;
1626 if (tty->link)
1627 tty->link->port->itty = NULL;
1628 cancel_work_sync(&tty->port->buf.work);
1629
1630 if (tty->link)
1631 tty_kref_put(tty->link);
1632 tty_kref_put(tty);
1633}
1634
1635/**
1636 * tty_release_checks - check a tty before real release
1637 * @tty: tty to check
1638 * @o_tty: link of @tty (if any)
1639 * @idx: index of the tty
1640 *
1641 * Performs some paranoid checking before true release of the @tty.
1642 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1643 */
1644static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1645 int idx)
1646{
1647#ifdef TTY_PARANOIA_CHECK
1648 if (idx < 0 || idx >= tty->driver->num) {
1649 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1650 __func__, tty->name);
1651 return -1;
1652 }
1653
1654 /* not much to check for devpts */
1655 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1656 return 0;
1657
1658 if (tty != tty->driver->ttys[idx]) {
1659 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1660 __func__, idx, tty->name);
1661 return -1;
1662 }
1663 if (tty->driver->other) {
1664 if (o_tty != tty->driver->other->ttys[idx]) {
1665 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1666 __func__, idx, tty->name);
1667 return -1;
1668 }
1669 if (o_tty->link != tty) {
1670 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1671 return -1;
1672 }
1673 }
1674#endif
1675 return 0;
1676}
1677
1678/**
1679 * tty_release - vfs callback for close
1680 * @inode: inode of tty
1681 * @filp: file pointer for handle to tty
1682 *
1683 * Called the last time each file handle is closed that references
1684 * this tty. There may however be several such references.
1685 *
1686 * Locking:
1687 * Takes bkl. See tty_release_dev
1688 *
1689 * Even releasing the tty structures is a tricky business.. We have
1690 * to be very careful that the structures are all released at the
1691 * same time, as interrupts might otherwise get the wrong pointers.
1692 *
1693 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1694 * lead to double frees or releasing memory still in use.
1695 */
1696
1697int tty_release(struct inode *inode, struct file *filp)
1698{
1699 struct tty_struct *tty = file_tty(filp);
1700 struct tty_struct *o_tty;
1701 int pty_master, tty_closing, o_tty_closing, do_sleep;
1702 int idx;
1703 char buf[64];
1704
1705 if (tty_paranoia_check(tty, inode, __func__))
1706 return 0;
1707
1708 tty_lock(tty);
1709 check_tty_count(tty, __func__);
1710
1711 __tty_fasync(-1, filp, 0);
1712
1713 idx = tty->index;
1714 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1715 tty->driver->subtype == PTY_TYPE_MASTER);
1716 /* Review: parallel close */
1717 o_tty = tty->link;
1718
1719 if (tty_release_checks(tty, o_tty, idx)) {
1720 tty_unlock(tty);
1721 return 0;
1722 }
1723
1724#ifdef TTY_DEBUG_HANGUP
1725 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1726 tty_name(tty, buf), tty->count);
1727#endif
1728
1729 if (tty->ops->close)
1730 tty->ops->close(tty, filp);
1731
1732 tty_unlock(tty);
1733 /*
1734 * Sanity check: if tty->count is going to zero, there shouldn't be
1735 * any waiters on tty->read_wait or tty->write_wait. We test the
1736 * wait queues and kick everyone out _before_ actually starting to
1737 * close. This ensures that we won't block while releasing the tty
1738 * structure.
1739 *
1740 * The test for the o_tty closing is necessary, since the master and
1741 * slave sides may close in any order. If the slave side closes out
1742 * first, its count will be one, since the master side holds an open.
1743 * Thus this test wouldn't be triggered at the time the slave closes,
1744 * so we do it now.
1745 *
1746 * Note that it's possible for the tty to be opened again while we're
1747 * flushing out waiters. By recalculating the closing flags before
1748 * each iteration we avoid any problems.
1749 */
1750 while (1) {
1751 /* Guard against races with tty->count changes elsewhere and
1752 opens on /dev/tty */
1753
1754 mutex_lock(&tty_mutex);
1755 tty_lock_pair(tty, o_tty);
1756 tty_closing = tty->count <= 1;
1757 o_tty_closing = o_tty &&
1758 (o_tty->count <= (pty_master ? 1 : 0));
1759 do_sleep = 0;
1760
1761 if (tty_closing) {
1762 if (waitqueue_active(&tty->read_wait)) {
1763 wake_up_poll(&tty->read_wait, POLLIN);
1764 do_sleep++;
1765 }
1766 if (waitqueue_active(&tty->write_wait)) {
1767 wake_up_poll(&tty->write_wait, POLLOUT);
1768 do_sleep++;
1769 }
1770 }
1771 if (o_tty_closing) {
1772 if (waitqueue_active(&o_tty->read_wait)) {
1773 wake_up_poll(&o_tty->read_wait, POLLIN);
1774 do_sleep++;
1775 }
1776 if (waitqueue_active(&o_tty->write_wait)) {
1777 wake_up_poll(&o_tty->write_wait, POLLOUT);
1778 do_sleep++;
1779 }
1780 }
1781 if (!do_sleep)
1782 break;
1783
1784 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1785 __func__, tty_name(tty, buf));
1786 tty_unlock_pair(tty, o_tty);
1787 mutex_unlock(&tty_mutex);
1788 schedule();
1789 }
1790
1791 /*
1792 * The closing flags are now consistent with the open counts on
1793 * both sides, and we've completed the last operation that could
1794 * block, so it's safe to proceed with closing.
1795 *
1796 * We must *not* drop the tty_mutex until we ensure that a further
1797 * entry into tty_open can not pick up this tty.
1798 */
1799 if (pty_master) {
1800 if (--o_tty->count < 0) {
1801 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1802 __func__, o_tty->count, tty_name(o_tty, buf));
1803 o_tty->count = 0;
1804 }
1805 }
1806 if (--tty->count < 0) {
1807 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1808 __func__, tty->count, tty_name(tty, buf));
1809 tty->count = 0;
1810 }
1811
1812 /*
1813 * We've decremented tty->count, so we need to remove this file
1814 * descriptor off the tty->tty_files list; this serves two
1815 * purposes:
1816 * - check_tty_count sees the correct number of file descriptors
1817 * associated with this tty.
1818 * - do_tty_hangup no longer sees this file descriptor as
1819 * something that needs to be handled for hangups.
1820 */
1821 tty_del_file(filp);
1822
1823 /*
1824 * Perform some housekeeping before deciding whether to return.
1825 *
1826 * Set the TTY_CLOSING flag if this was the last open. In the
1827 * case of a pty we may have to wait around for the other side
1828 * to close, and TTY_CLOSING makes sure we can't be reopened.
1829 */
1830 if (tty_closing)
1831 set_bit(TTY_CLOSING, &tty->flags);
1832 if (o_tty_closing)
1833 set_bit(TTY_CLOSING, &o_tty->flags);
1834
1835 /*
1836 * If _either_ side is closing, make sure there aren't any
1837 * processes that still think tty or o_tty is their controlling
1838 * tty.
1839 */
1840 if (tty_closing || o_tty_closing) {
1841 read_lock(&tasklist_lock);
1842 session_clear_tty(tty->session);
1843 if (o_tty)
1844 session_clear_tty(o_tty->session);
1845 read_unlock(&tasklist_lock);
1846 }
1847
1848 mutex_unlock(&tty_mutex);
1849 tty_unlock_pair(tty, o_tty);
1850 /* At this point the TTY_CLOSING flag should ensure a dead tty
1851 cannot be re-opened by a racing opener */
1852
1853 /* check whether both sides are closing ... */
1854 if (!tty_closing || (o_tty && !o_tty_closing))
1855 return 0;
1856
1857#ifdef TTY_DEBUG_HANGUP
1858 printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
1859#endif
1860 /*
1861 * Ask the line discipline code to release its structures
1862 */
1863 tty_ldisc_release(tty, o_tty);
1864
1865 /* Wait for pending work before tty destruction commmences */
1866 tty_flush_works(tty);
1867 if (o_tty)
1868 tty_flush_works(o_tty);
1869
1870#ifdef TTY_DEBUG_HANGUP
1871 printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
1872#endif
1873 /*
1874 * The release_tty function takes care of the details of clearing
1875 * the slots and preserving the termios structure. The tty_unlock_pair
1876 * should be safe as we keep a kref while the tty is locked (so the
1877 * unlock never unlocks a freed tty).
1878 */
1879 mutex_lock(&tty_mutex);
1880 release_tty(tty, idx);
1881 mutex_unlock(&tty_mutex);
1882
1883 return 0;
1884}
1885
1886/**
1887 * tty_open_current_tty - get tty of current task for open
1888 * @device: device number
1889 * @filp: file pointer to tty
1890 * @return: tty of the current task iff @device is /dev/tty
1891 *
1892 * We cannot return driver and index like for the other nodes because
1893 * devpts will not work then. It expects inodes to be from devpts FS.
1894 *
1895 * We need to move to returning a refcounted object from all the lookup
1896 * paths including this one.
1897 */
1898static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1899{
1900 struct tty_struct *tty;
1901
1902 if (device != MKDEV(TTYAUX_MAJOR, 0))
1903 return NULL;
1904
1905 tty = get_current_tty();
1906 if (!tty)
1907 return ERR_PTR(-ENXIO);
1908
1909 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1910 /* noctty = 1; */
1911 tty_kref_put(tty);
1912 /* FIXME: we put a reference and return a TTY! */
1913 /* This is only safe because the caller holds tty_mutex */
1914 return tty;
1915}
1916
1917/**
1918 * tty_lookup_driver - lookup a tty driver for a given device file
1919 * @device: device number
1920 * @filp: file pointer to tty
1921 * @noctty: set if the device should not become a controlling tty
1922 * @index: index for the device in the @return driver
1923 * @return: driver for this inode (with increased refcount)
1924 *
1925 * If @return is not erroneous, the caller is responsible to decrement the
1926 * refcount by tty_driver_kref_put.
1927 *
1928 * Locking: tty_mutex protects get_tty_driver
1929 */
1930static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1931 int *noctty, int *index)
1932{
1933 struct tty_driver *driver;
1934
1935 switch (device) {
1936#ifdef CONFIG_VT
1937 case MKDEV(TTY_MAJOR, 0): {
1938 extern struct tty_driver *console_driver;
1939 driver = tty_driver_kref_get(console_driver);
1940 *index = fg_console;
1941 *noctty = 1;
1942 break;
1943 }
1944#endif
1945 case MKDEV(TTYAUX_MAJOR, 1): {
1946 struct tty_driver *console_driver = console_device(index);
1947 if (console_driver) {
1948 driver = tty_driver_kref_get(console_driver);
1949 if (driver) {
1950 /* Don't let /dev/console block */
1951 filp->f_flags |= O_NONBLOCK;
1952 *noctty = 1;
1953 break;
1954 }
1955 }
1956 return ERR_PTR(-ENODEV);
1957 }
1958 default:
1959 driver = get_tty_driver(device, index);
1960 if (!driver)
1961 return ERR_PTR(-ENODEV);
1962 break;
1963 }
1964 return driver;
1965}
1966
1967/**
1968 * tty_open - open a tty device
1969 * @inode: inode of device file
1970 * @filp: file pointer to tty
1971 *
1972 * tty_open and tty_release keep up the tty count that contains the
1973 * number of opens done on a tty. We cannot use the inode-count, as
1974 * different inodes might point to the same tty.
1975 *
1976 * Open-counting is needed for pty masters, as well as for keeping
1977 * track of serial lines: DTR is dropped when the last close happens.
1978 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1979 *
1980 * The termios state of a pty is reset on first open so that
1981 * settings don't persist across reuse.
1982 *
1983 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1984 * tty->count should protect the rest.
1985 * ->siglock protects ->signal/->sighand
1986 *
1987 * Note: the tty_unlock/lock cases without a ref are only safe due to
1988 * tty_mutex
1989 */
1990
1991static int tty_open(struct inode *inode, struct file *filp)
1992{
1993 struct tty_struct *tty;
1994 int noctty, retval;
1995 struct tty_driver *driver = NULL;
1996 int index;
1997 dev_t device = inode->i_rdev;
1998 unsigned saved_flags = filp->f_flags;
1999
2000 nonseekable_open(inode, filp);
2001
2002retry_open:
2003 retval = tty_alloc_file(filp);
2004 if (retval)
2005 return -ENOMEM;
2006
2007 noctty = filp->f_flags & O_NOCTTY;
2008 index = -1;
2009 retval = 0;
2010
2011 mutex_lock(&tty_mutex);
2012 /* This is protected by the tty_mutex */
2013 tty = tty_open_current_tty(device, filp);
2014 if (IS_ERR(tty)) {
2015 retval = PTR_ERR(tty);
2016 goto err_unlock;
2017 } else if (!tty) {
2018 driver = tty_lookup_driver(device, filp, &noctty, &index);
2019 if (IS_ERR(driver)) {
2020 retval = PTR_ERR(driver);
2021 goto err_unlock;
2022 }
2023
2024 /* check whether we're reopening an existing tty */
2025 tty = tty_driver_lookup_tty(driver, inode, index);
2026 if (IS_ERR(tty)) {
2027 retval = PTR_ERR(tty);
2028 goto err_unlock;
2029 }
2030 }
2031
2032 if (tty) {
2033 tty_lock(tty);
2034 retval = tty_reopen(tty);
2035 if (retval < 0) {
2036 tty_unlock(tty);
2037 tty = ERR_PTR(retval);
2038 }
2039 } else /* Returns with the tty_lock held for now */
2040 tty = tty_init_dev(driver, index);
2041
2042 mutex_unlock(&tty_mutex);
2043 if (driver)
2044 tty_driver_kref_put(driver);
2045 if (IS_ERR(tty)) {
2046 retval = PTR_ERR(tty);
2047 goto err_file;
2048 }
2049
2050 tty_add_file(tty, filp);
2051
2052 check_tty_count(tty, __func__);
2053 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2054 tty->driver->subtype == PTY_TYPE_MASTER)
2055 noctty = 1;
2056#ifdef TTY_DEBUG_HANGUP
2057 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
2058#endif
2059 if (tty->ops->open)
2060 retval = tty->ops->open(tty, filp);
2061 else
2062 retval = -ENODEV;
2063 filp->f_flags = saved_flags;
2064
2065 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
2066 !capable(CAP_SYS_ADMIN))
2067 retval = -EBUSY;
2068
2069 if (retval) {
2070#ifdef TTY_DEBUG_HANGUP
2071 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
2072 retval, tty->name);
2073#endif
2074 tty_unlock(tty); /* need to call tty_release without BTM */
2075 tty_release(inode, filp);
2076 if (retval != -ERESTARTSYS)
2077 return retval;
2078
2079 if (signal_pending(current))
2080 return retval;
2081
2082 schedule();
2083 /*
2084 * Need to reset f_op in case a hangup happened.
2085 */
2086 if (filp->f_op == &hung_up_tty_fops)
2087 filp->f_op = &tty_fops;
2088 goto retry_open;
2089 }
2090 clear_bit(TTY_HUPPED, &tty->flags);
2091 tty_unlock(tty);
2092
2093
2094 mutex_lock(&tty_mutex);
2095 tty_lock(tty);
2096 spin_lock_irq(¤t->sighand->siglock);
2097 if (!noctty &&
2098 current->signal->leader &&
2099 !current->signal->tty &&
2100 tty->session == NULL)
2101 __proc_set_tty(current, tty);
2102 spin_unlock_irq(¤t->sighand->siglock);
2103 tty_unlock(tty);
2104 mutex_unlock(&tty_mutex);
2105 return 0;
2106err_unlock:
2107 mutex_unlock(&tty_mutex);
2108 /* after locks to avoid deadlock */
2109 if (!IS_ERR_OR_NULL(driver))
2110 tty_driver_kref_put(driver);
2111err_file:
2112 tty_free_file(filp);
2113 return retval;
2114}
2115
2116
2117
2118/**
2119 * tty_poll - check tty status
2120 * @filp: file being polled
2121 * @wait: poll wait structures to update
2122 *
2123 * Call the line discipline polling method to obtain the poll
2124 * status of the device.
2125 *
2126 * Locking: locks called line discipline but ldisc poll method
2127 * may be re-entered freely by other callers.
2128 */
2129
2130static unsigned int tty_poll(struct file *filp, poll_table *wait)
2131{
2132 struct tty_struct *tty = file_tty(filp);
2133 struct tty_ldisc *ld;
2134 int ret = 0;
2135
2136 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2137 return 0;
2138
2139 ld = tty_ldisc_ref_wait(tty);
2140 if (ld->ops->poll)
2141 ret = (ld->ops->poll)(tty, filp, wait);
2142 tty_ldisc_deref(ld);
2143 return ret;
2144}
2145
2146static int __tty_fasync(int fd, struct file *filp, int on)
2147{
2148 struct tty_struct *tty = file_tty(filp);
2149 struct tty_ldisc *ldisc;
2150 unsigned long flags;
2151 int retval = 0;
2152
2153 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2154 goto out;
2155
2156 retval = fasync_helper(fd, filp, on, &tty->fasync);
2157 if (retval <= 0)
2158 goto out;
2159
2160 ldisc = tty_ldisc_ref(tty);
2161 if (ldisc) {
2162 if (ldisc->ops->fasync)
2163 ldisc->ops->fasync(tty, on);
2164 tty_ldisc_deref(ldisc);
2165 }
2166
2167 if (on) {
2168 enum pid_type type;
2169 struct pid *pid;
2170
2171 spin_lock_irqsave(&tty->ctrl_lock, flags);
2172 if (tty->pgrp) {
2173 pid = tty->pgrp;
2174 type = PIDTYPE_PGID;
2175 } else {
2176 pid = task_pid(current);
2177 type = PIDTYPE_PID;
2178 }
2179 get_pid(pid);
2180 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2181 retval = __f_setown(filp, pid, type, 0);
2182 put_pid(pid);
2183 }
2184out:
2185 return retval;
2186}
2187
2188static int tty_fasync(int fd, struct file *filp, int on)
2189{
2190 struct tty_struct *tty = file_tty(filp);
2191 int retval;
2192
2193 tty_lock(tty);
2194 retval = __tty_fasync(fd, filp, on);
2195 tty_unlock(tty);
2196
2197 return retval;
2198}
2199
2200/**
2201 * tiocsti - fake input character
2202 * @tty: tty to fake input into
2203 * @p: pointer to character
2204 *
2205 * Fake input to a tty device. Does the necessary locking and
2206 * input management.
2207 *
2208 * FIXME: does not honour flow control ??
2209 *
2210 * Locking:
2211 * Called functions take tty_ldiscs_lock
2212 * current->signal->tty check is safe without locks
2213 *
2214 * FIXME: may race normal receive processing
2215 */
2216
2217static int tiocsti(struct tty_struct *tty, char __user *p)
2218{
2219 char ch, mbz = 0;
2220 struct tty_ldisc *ld;
2221
2222 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2223 return -EPERM;
2224 if (get_user(ch, p))
2225 return -EFAULT;
2226 tty_audit_tiocsti(tty, ch);
2227 ld = tty_ldisc_ref_wait(tty);
2228 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2229 tty_ldisc_deref(ld);
2230 return 0;
2231}
2232
2233/**
2234 * tiocgwinsz - implement window query ioctl
2235 * @tty; tty
2236 * @arg: user buffer for result
2237 *
2238 * Copies the kernel idea of the window size into the user buffer.
2239 *
2240 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2241 * is consistent.
2242 */
2243
2244static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2245{
2246 int err;
2247
2248 mutex_lock(&tty->winsize_mutex);
2249 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2250 mutex_unlock(&tty->winsize_mutex);
2251
2252 return err ? -EFAULT: 0;
2253}
2254
2255/**
2256 * tty_do_resize - resize event
2257 * @tty: tty being resized
2258 * @rows: rows (character)
2259 * @cols: cols (character)
2260 *
2261 * Update the termios variables and send the necessary signals to
2262 * peform a terminal resize correctly
2263 */
2264
2265int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2266{
2267 struct pid *pgrp;
2268 unsigned long flags;
2269
2270 /* Lock the tty */
2271 mutex_lock(&tty->winsize_mutex);
2272 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2273 goto done;
2274 /* Get the PID values and reference them so we can
2275 avoid holding the tty ctrl lock while sending signals */
2276 spin_lock_irqsave(&tty->ctrl_lock, flags);
2277 pgrp = get_pid(tty->pgrp);
2278 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2279
2280 if (pgrp)
2281 kill_pgrp(pgrp, SIGWINCH, 1);
2282 put_pid(pgrp);
2283
2284 tty->winsize = *ws;
2285done:
2286 mutex_unlock(&tty->winsize_mutex);
2287 return 0;
2288}
2289EXPORT_SYMBOL(tty_do_resize);
2290
2291/**
2292 * tiocswinsz - implement window size set ioctl
2293 * @tty; tty side of tty
2294 * @arg: user buffer for result
2295 *
2296 * Copies the user idea of the window size to the kernel. Traditionally
2297 * this is just advisory information but for the Linux console it
2298 * actually has driver level meaning and triggers a VC resize.
2299 *
2300 * Locking:
2301 * Driver dependent. The default do_resize method takes the
2302 * tty termios mutex and ctrl_lock. The console takes its own lock
2303 * then calls into the default method.
2304 */
2305
2306static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2307{
2308 struct winsize tmp_ws;
2309 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2310 return -EFAULT;
2311
2312 if (tty->ops->resize)
2313 return tty->ops->resize(tty, &tmp_ws);
2314 else
2315 return tty_do_resize(tty, &tmp_ws);
2316}
2317
2318/**
2319 * tioccons - allow admin to move logical console
2320 * @file: the file to become console
2321 *
2322 * Allow the administrator to move the redirected console device
2323 *
2324 * Locking: uses redirect_lock to guard the redirect information
2325 */
2326
2327static int tioccons(struct file *file)
2328{
2329 if (!capable(CAP_SYS_ADMIN))
2330 return -EPERM;
2331 if (file->f_op->write == redirected_tty_write) {
2332 struct file *f;
2333 spin_lock(&redirect_lock);
2334 f = redirect;
2335 redirect = NULL;
2336 spin_unlock(&redirect_lock);
2337 if (f)
2338 fput(f);
2339 return 0;
2340 }
2341 spin_lock(&redirect_lock);
2342 if (redirect) {
2343 spin_unlock(&redirect_lock);
2344 return -EBUSY;
2345 }
2346 redirect = get_file(file);
2347 spin_unlock(&redirect_lock);
2348 return 0;
2349}
2350
2351/**
2352 * fionbio - non blocking ioctl
2353 * @file: file to set blocking value
2354 * @p: user parameter
2355 *
2356 * Historical tty interfaces had a blocking control ioctl before
2357 * the generic functionality existed. This piece of history is preserved
2358 * in the expected tty API of posix OS's.
2359 *
2360 * Locking: none, the open file handle ensures it won't go away.
2361 */
2362
2363static int fionbio(struct file *file, int __user *p)
2364{
2365 int nonblock;
2366
2367 if (get_user(nonblock, p))
2368 return -EFAULT;
2369
2370 spin_lock(&file->f_lock);
2371 if (nonblock)
2372 file->f_flags |= O_NONBLOCK;
2373 else
2374 file->f_flags &= ~O_NONBLOCK;
2375 spin_unlock(&file->f_lock);
2376 return 0;
2377}
2378
2379/**
2380 * tiocsctty - set controlling tty
2381 * @tty: tty structure
2382 * @arg: user argument
2383 *
2384 * This ioctl is used to manage job control. It permits a session
2385 * leader to set this tty as the controlling tty for the session.
2386 *
2387 * Locking:
2388 * Takes tty_mutex() to protect tty instance
2389 * Takes tasklist_lock internally to walk sessions
2390 * Takes ->siglock() when updating signal->tty
2391 */
2392
2393static int tiocsctty(struct tty_struct *tty, int arg)
2394{
2395 int ret = 0;
2396 if (current->signal->leader && (task_session(current) == tty->session))
2397 return ret;
2398
2399 mutex_lock(&tty_mutex);
2400 /*
2401 * The process must be a session leader and
2402 * not have a controlling tty already.
2403 */
2404 if (!current->signal->leader || current->signal->tty) {
2405 ret = -EPERM;
2406 goto unlock;
2407 }
2408
2409 if (tty->session) {
2410 /*
2411 * This tty is already the controlling
2412 * tty for another session group!
2413 */
2414 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2415 /*
2416 * Steal it away
2417 */
2418 read_lock(&tasklist_lock);
2419 session_clear_tty(tty->session);
2420 read_unlock(&tasklist_lock);
2421 } else {
2422 ret = -EPERM;
2423 goto unlock;
2424 }
2425 }
2426 proc_set_tty(current, tty);
2427unlock:
2428 mutex_unlock(&tty_mutex);
2429 return ret;
2430}
2431
2432/**
2433 * tty_get_pgrp - return a ref counted pgrp pid
2434 * @tty: tty to read
2435 *
2436 * Returns a refcounted instance of the pid struct for the process
2437 * group controlling the tty.
2438 */
2439
2440struct pid *tty_get_pgrp(struct tty_struct *tty)
2441{
2442 unsigned long flags;
2443 struct pid *pgrp;
2444
2445 spin_lock_irqsave(&tty->ctrl_lock, flags);
2446 pgrp = get_pid(tty->pgrp);
2447 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2448
2449 return pgrp;
2450}
2451EXPORT_SYMBOL_GPL(tty_get_pgrp);
2452
2453/**
2454 * tiocgpgrp - get process group
2455 * @tty: tty passed by user
2456 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2457 * @p: returned pid
2458 *
2459 * Obtain the process group of the tty. If there is no process group
2460 * return an error.
2461 *
2462 * Locking: none. Reference to current->signal->tty is safe.
2463 */
2464
2465static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2466{
2467 struct pid *pid;
2468 int ret;
2469 /*
2470 * (tty == real_tty) is a cheap way of
2471 * testing if the tty is NOT a master pty.
2472 */
2473 if (tty == real_tty && current->signal->tty != real_tty)
2474 return -ENOTTY;
2475 pid = tty_get_pgrp(real_tty);
2476 ret = put_user(pid_vnr(pid), p);
2477 put_pid(pid);
2478 return ret;
2479}
2480
2481/**
2482 * tiocspgrp - attempt to set process group
2483 * @tty: tty passed by user
2484 * @real_tty: tty side device matching tty passed by user
2485 * @p: pid pointer
2486 *
2487 * Set the process group of the tty to the session passed. Only
2488 * permitted where the tty session is our session.
2489 *
2490 * Locking: RCU, ctrl lock
2491 */
2492
2493static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2494{
2495 struct pid *pgrp;
2496 pid_t pgrp_nr;
2497 int retval = tty_check_change(real_tty);
2498 unsigned long flags;
2499
2500 if (retval == -EIO)
2501 return -ENOTTY;
2502 if (retval)
2503 return retval;
2504 if (!current->signal->tty ||
2505 (current->signal->tty != real_tty) ||
2506 (real_tty->session != task_session(current)))
2507 return -ENOTTY;
2508 if (get_user(pgrp_nr, p))
2509 return -EFAULT;
2510 if (pgrp_nr < 0)
2511 return -EINVAL;
2512 rcu_read_lock();
2513 pgrp = find_vpid(pgrp_nr);
2514 retval = -ESRCH;
2515 if (!pgrp)
2516 goto out_unlock;
2517 retval = -EPERM;
2518 if (session_of_pgrp(pgrp) != task_session(current))
2519 goto out_unlock;
2520 retval = 0;
2521 spin_lock_irqsave(&tty->ctrl_lock, flags);
2522 put_pid(real_tty->pgrp);
2523 real_tty->pgrp = get_pid(pgrp);
2524 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2525out_unlock:
2526 rcu_read_unlock();
2527 return retval;
2528}
2529
2530/**
2531 * tiocgsid - get session id
2532 * @tty: tty passed by user
2533 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2534 * @p: pointer to returned session id
2535 *
2536 * Obtain the session id of the tty. If there is no session
2537 * return an error.
2538 *
2539 * Locking: none. Reference to current->signal->tty is safe.
2540 */
2541
2542static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2543{
2544 /*
2545 * (tty == real_tty) is a cheap way of
2546 * testing if the tty is NOT a master pty.
2547 */
2548 if (tty == real_tty && current->signal->tty != real_tty)
2549 return -ENOTTY;
2550 if (!real_tty->session)
2551 return -ENOTTY;
2552 return put_user(pid_vnr(real_tty->session), p);
2553}
2554
2555/**
2556 * tiocsetd - set line discipline
2557 * @tty: tty device
2558 * @p: pointer to user data
2559 *
2560 * Set the line discipline according to user request.
2561 *
2562 * Locking: see tty_set_ldisc, this function is just a helper
2563 */
2564
2565static int tiocsetd(struct tty_struct *tty, int __user *p)
2566{
2567 int ldisc;
2568 int ret;
2569
2570 if (get_user(ldisc, p))
2571 return -EFAULT;
2572
2573 ret = tty_set_ldisc(tty, ldisc);
2574
2575 return ret;
2576}
2577
2578/**
2579 * send_break - performed time break
2580 * @tty: device to break on
2581 * @duration: timeout in mS
2582 *
2583 * Perform a timed break on hardware that lacks its own driver level
2584 * timed break functionality.
2585 *
2586 * Locking:
2587 * atomic_write_lock serializes
2588 *
2589 */
2590
2591static int send_break(struct tty_struct *tty, unsigned int duration)
2592{
2593 int retval;
2594
2595 if (tty->ops->break_ctl == NULL)
2596 return 0;
2597
2598 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2599 retval = tty->ops->break_ctl(tty, duration);
2600 else {
2601 /* Do the work ourselves */
2602 if (tty_write_lock(tty, 0) < 0)
2603 return -EINTR;
2604 retval = tty->ops->break_ctl(tty, -1);
2605 if (retval)
2606 goto out;
2607 if (!signal_pending(current))
2608 msleep_interruptible(duration);
2609 retval = tty->ops->break_ctl(tty, 0);
2610out:
2611 tty_write_unlock(tty);
2612 if (signal_pending(current))
2613 retval = -EINTR;
2614 }
2615 return retval;
2616}
2617
2618/**
2619 * tty_tiocmget - get modem status
2620 * @tty: tty device
2621 * @file: user file pointer
2622 * @p: pointer to result
2623 *
2624 * Obtain the modem status bits from the tty driver if the feature
2625 * is supported. Return -EINVAL if it is not available.
2626 *
2627 * Locking: none (up to the driver)
2628 */
2629
2630static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2631{
2632 int retval = -EINVAL;
2633
2634 if (tty->ops->tiocmget) {
2635 retval = tty->ops->tiocmget(tty);
2636
2637 if (retval >= 0)
2638 retval = put_user(retval, p);
2639 }
2640 return retval;
2641}
2642
2643/**
2644 * tty_tiocmset - set modem status
2645 * @tty: tty device
2646 * @cmd: command - clear bits, set bits or set all
2647 * @p: pointer to desired bits
2648 *
2649 * Set the modem status bits from the tty driver if the feature
2650 * is supported. Return -EINVAL if it is not available.
2651 *
2652 * Locking: none (up to the driver)
2653 */
2654
2655static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2656 unsigned __user *p)
2657{
2658 int retval;
2659 unsigned int set, clear, val;
2660
2661 if (tty->ops->tiocmset == NULL)
2662 return -EINVAL;
2663
2664 retval = get_user(val, p);
2665 if (retval)
2666 return retval;
2667 set = clear = 0;
2668 switch (cmd) {
2669 case TIOCMBIS:
2670 set = val;
2671 break;
2672 case TIOCMBIC:
2673 clear = val;
2674 break;
2675 case TIOCMSET:
2676 set = val;
2677 clear = ~val;
2678 break;
2679 }
2680 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2681 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2682 return tty->ops->tiocmset(tty, set, clear);
2683}
2684
2685static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2686{
2687 int retval = -EINVAL;
2688 struct serial_icounter_struct icount;
2689 memset(&icount, 0, sizeof(icount));
2690 if (tty->ops->get_icount)
2691 retval = tty->ops->get_icount(tty, &icount);
2692 if (retval != 0)
2693 return retval;
2694 if (copy_to_user(arg, &icount, sizeof(icount)))
2695 return -EFAULT;
2696 return 0;
2697}
2698
2699struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2700{
2701 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2702 tty->driver->subtype == PTY_TYPE_MASTER)
2703 tty = tty->link;
2704 return tty;
2705}
2706EXPORT_SYMBOL(tty_pair_get_tty);
2707
2708struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2709{
2710 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2711 tty->driver->subtype == PTY_TYPE_MASTER)
2712 return tty;
2713 return tty->link;
2714}
2715EXPORT_SYMBOL(tty_pair_get_pty);
2716
2717/*
2718 * Split this up, as gcc can choke on it otherwise..
2719 */
2720long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2721{
2722 struct tty_struct *tty = file_tty(file);
2723 struct tty_struct *real_tty;
2724 void __user *p = (void __user *)arg;
2725 int retval;
2726 struct tty_ldisc *ld;
2727
2728 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2729 return -EINVAL;
2730
2731 real_tty = tty_pair_get_tty(tty);
2732
2733 /*
2734 * Factor out some common prep work
2735 */
2736 switch (cmd) {
2737 case TIOCSETD:
2738 case TIOCSBRK:
2739 case TIOCCBRK:
2740 case TCSBRK:
2741 case TCSBRKP:
2742 retval = tty_check_change(tty);
2743 if (retval)
2744 return retval;
2745 if (cmd != TIOCCBRK) {
2746 tty_wait_until_sent(tty, 0);
2747 if (signal_pending(current))
2748 return -EINTR;
2749 }
2750 break;
2751 }
2752
2753 /*
2754 * Now do the stuff.
2755 */
2756 switch (cmd) {
2757 case TIOCSTI:
2758 return tiocsti(tty, p);
2759 case TIOCGWINSZ:
2760 return tiocgwinsz(real_tty, p);
2761 case TIOCSWINSZ:
2762 return tiocswinsz(real_tty, p);
2763 case TIOCCONS:
2764 return real_tty != tty ? -EINVAL : tioccons(file);
2765 case FIONBIO:
2766 return fionbio(file, p);
2767 case TIOCEXCL:
2768 set_bit(TTY_EXCLUSIVE, &tty->flags);
2769 return 0;
2770 case TIOCNXCL:
2771 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2772 return 0;
2773 case TIOCGEXCL:
2774 {
2775 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2776 return put_user(excl, (int __user *)p);
2777 }
2778 case TIOCNOTTY:
2779 if (current->signal->tty != tty)
2780 return -ENOTTY;
2781 no_tty();
2782 return 0;
2783 case TIOCSCTTY:
2784 return tiocsctty(tty, arg);
2785 case TIOCGPGRP:
2786 return tiocgpgrp(tty, real_tty, p);
2787 case TIOCSPGRP:
2788 return tiocspgrp(tty, real_tty, p);
2789 case TIOCGSID:
2790 return tiocgsid(tty, real_tty, p);
2791 case TIOCGETD:
2792 return put_user(tty->ldisc->ops->num, (int __user *)p);
2793 case TIOCSETD:
2794 return tiocsetd(tty, p);
2795 case TIOCVHANGUP:
2796 if (!capable(CAP_SYS_ADMIN))
2797 return -EPERM;
2798 tty_vhangup(tty);
2799 return 0;
2800 case TIOCGDEV:
2801 {
2802 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2803 return put_user(ret, (unsigned int __user *)p);
2804 }
2805 /*
2806 * Break handling
2807 */
2808 case TIOCSBRK: /* Turn break on, unconditionally */
2809 if (tty->ops->break_ctl)
2810 return tty->ops->break_ctl(tty, -1);
2811 return 0;
2812 case TIOCCBRK: /* Turn break off, unconditionally */
2813 if (tty->ops->break_ctl)
2814 return tty->ops->break_ctl(tty, 0);
2815 return 0;
2816 case TCSBRK: /* SVID version: non-zero arg --> no break */
2817 /* non-zero arg means wait for all output data
2818 * to be sent (performed above) but don't send break.
2819 * This is used by the tcdrain() termios function.
2820 */
2821 if (!arg)
2822 return send_break(tty, 250);
2823 return 0;
2824 case TCSBRKP: /* support for POSIX tcsendbreak() */
2825 return send_break(tty, arg ? arg*100 : 250);
2826
2827 case TIOCMGET:
2828 return tty_tiocmget(tty, p);
2829 case TIOCMSET:
2830 case TIOCMBIC:
2831 case TIOCMBIS:
2832 return tty_tiocmset(tty, cmd, p);
2833 case TIOCGICOUNT:
2834 retval = tty_tiocgicount(tty, p);
2835 /* For the moment allow fall through to the old method */
2836 if (retval != -EINVAL)
2837 return retval;
2838 break;
2839 case TCFLSH:
2840 switch (arg) {
2841 case TCIFLUSH:
2842 case TCIOFLUSH:
2843 /* flush tty buffer and allow ldisc to process ioctl */
2844 tty_buffer_flush(tty);
2845 break;
2846 }
2847 break;
2848 }
2849 if (tty->ops->ioctl) {
2850 retval = (tty->ops->ioctl)(tty, cmd, arg);
2851 if (retval != -ENOIOCTLCMD)
2852 return retval;
2853 }
2854 ld = tty_ldisc_ref_wait(tty);
2855 retval = -EINVAL;
2856 if (ld->ops->ioctl) {
2857 retval = ld->ops->ioctl(tty, file, cmd, arg);
2858 if (retval == -ENOIOCTLCMD)
2859 retval = -ENOTTY;
2860 }
2861 tty_ldisc_deref(ld);
2862 return retval;
2863}
2864
2865#ifdef CONFIG_COMPAT
2866static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2867 unsigned long arg)
2868{
2869 struct tty_struct *tty = file_tty(file);
2870 struct tty_ldisc *ld;
2871 int retval = -ENOIOCTLCMD;
2872
2873 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2874 return -EINVAL;
2875
2876 if (tty->ops->compat_ioctl) {
2877 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2878 if (retval != -ENOIOCTLCMD)
2879 return retval;
2880 }
2881
2882 ld = tty_ldisc_ref_wait(tty);
2883 if (ld->ops->compat_ioctl)
2884 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2885 else
2886 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2887 tty_ldisc_deref(ld);
2888
2889 return retval;
2890}
2891#endif
2892
2893static int this_tty(const void *t, struct file *file, unsigned fd)
2894{
2895 if (likely(file->f_op->read != tty_read))
2896 return 0;
2897 return file_tty(file) != t ? 0 : fd + 1;
2898}
2899
2900/*
2901 * This implements the "Secure Attention Key" --- the idea is to
2902 * prevent trojan horses by killing all processes associated with this
2903 * tty when the user hits the "Secure Attention Key". Required for
2904 * super-paranoid applications --- see the Orange Book for more details.
2905 *
2906 * This code could be nicer; ideally it should send a HUP, wait a few
2907 * seconds, then send a INT, and then a KILL signal. But you then
2908 * have to coordinate with the init process, since all processes associated
2909 * with the current tty must be dead before the new getty is allowed
2910 * to spawn.
2911 *
2912 * Now, if it would be correct ;-/ The current code has a nasty hole -
2913 * it doesn't catch files in flight. We may send the descriptor to ourselves
2914 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2915 *
2916 * Nasty bug: do_SAK is being called in interrupt context. This can
2917 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2918 */
2919void __do_SAK(struct tty_struct *tty)
2920{
2921#ifdef TTY_SOFT_SAK
2922 tty_hangup(tty);
2923#else
2924 struct task_struct *g, *p;
2925 struct pid *session;
2926 int i;
2927
2928 if (!tty)
2929 return;
2930 session = tty->session;
2931
2932 tty_ldisc_flush(tty);
2933
2934 tty_driver_flush_buffer(tty);
2935
2936 read_lock(&tasklist_lock);
2937 /* Kill the entire session */
2938 do_each_pid_task(session, PIDTYPE_SID, p) {
2939 printk(KERN_NOTICE "SAK: killed process %d"
2940 " (%s): task_session(p)==tty->session\n",
2941 task_pid_nr(p), p->comm);
2942 send_sig(SIGKILL, p, 1);
2943 } while_each_pid_task(session, PIDTYPE_SID, p);
2944 /* Now kill any processes that happen to have the
2945 * tty open.
2946 */
2947 do_each_thread(g, p) {
2948 if (p->signal->tty == tty) {
2949 printk(KERN_NOTICE "SAK: killed process %d"
2950 " (%s): task_session(p)==tty->session\n",
2951 task_pid_nr(p), p->comm);
2952 send_sig(SIGKILL, p, 1);
2953 continue;
2954 }
2955 task_lock(p);
2956 i = iterate_fd(p->files, 0, this_tty, tty);
2957 if (i != 0) {
2958 printk(KERN_NOTICE "SAK: killed process %d"
2959 " (%s): fd#%d opened to the tty\n",
2960 task_pid_nr(p), p->comm, i - 1);
2961 force_sig(SIGKILL, p);
2962 }
2963 task_unlock(p);
2964 } while_each_thread(g, p);
2965 read_unlock(&tasklist_lock);
2966#endif
2967}
2968
2969static void do_SAK_work(struct work_struct *work)
2970{
2971 struct tty_struct *tty =
2972 container_of(work, struct tty_struct, SAK_work);
2973 __do_SAK(tty);
2974}
2975
2976/*
2977 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2978 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2979 * the values which we write to it will be identical to the values which it
2980 * already has. --akpm
2981 */
2982void do_SAK(struct tty_struct *tty)
2983{
2984 if (!tty)
2985 return;
2986 schedule_work(&tty->SAK_work);
2987}
2988
2989EXPORT_SYMBOL(do_SAK);
2990
2991static int dev_match_devt(struct device *dev, const void *data)
2992{
2993 const dev_t *devt = data;
2994 return dev->devt == *devt;
2995}
2996
2997/* Must put_device() after it's unused! */
2998static struct device *tty_get_device(struct tty_struct *tty)
2999{
3000 dev_t devt = tty_devnum(tty);
3001 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3002}
3003
3004
3005/**
3006 * initialize_tty_struct
3007 * @tty: tty to initialize
3008 *
3009 * This subroutine initializes a tty structure that has been newly
3010 * allocated.
3011 *
3012 * Locking: none - tty in question must not be exposed at this point
3013 */
3014
3015void initialize_tty_struct(struct tty_struct *tty,
3016 struct tty_driver *driver, int idx)
3017{
3018 memset(tty, 0, sizeof(struct tty_struct));
3019 kref_init(&tty->kref);
3020 tty->magic = TTY_MAGIC;
3021 tty_ldisc_init(tty);
3022 tty->session = NULL;
3023 tty->pgrp = NULL;
3024 mutex_init(&tty->legacy_mutex);
3025 mutex_init(&tty->throttle_mutex);
3026 init_rwsem(&tty->termios_rwsem);
3027 mutex_init(&tty->winsize_mutex);
3028 init_ldsem(&tty->ldisc_sem);
3029 init_waitqueue_head(&tty->write_wait);
3030 init_waitqueue_head(&tty->read_wait);
3031 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3032 mutex_init(&tty->atomic_write_lock);
3033 spin_lock_init(&tty->ctrl_lock);
3034 INIT_LIST_HEAD(&tty->tty_files);
3035 INIT_WORK(&tty->SAK_work, do_SAK_work);
3036
3037 tty->driver = driver;
3038 tty->ops = driver->ops;
3039 tty->index = idx;
3040 tty_line_name(driver, idx, tty->name);
3041 tty->dev = tty_get_device(tty);
3042}
3043
3044/**
3045 * deinitialize_tty_struct
3046 * @tty: tty to deinitialize
3047 *
3048 * This subroutine deinitializes a tty structure that has been newly
3049 * allocated but tty_release cannot be called on that yet.
3050 *
3051 * Locking: none - tty in question must not be exposed at this point
3052 */
3053void deinitialize_tty_struct(struct tty_struct *tty)
3054{
3055 tty_ldisc_deinit(tty);
3056}
3057
3058/**
3059 * tty_put_char - write one character to a tty
3060 * @tty: tty
3061 * @ch: character
3062 *
3063 * Write one byte to the tty using the provided put_char method
3064 * if present. Returns the number of characters successfully output.
3065 *
3066 * Note: the specific put_char operation in the driver layer may go
3067 * away soon. Don't call it directly, use this method
3068 */
3069
3070int tty_put_char(struct tty_struct *tty, unsigned char ch)
3071{
3072 if (tty->ops->put_char)
3073 return tty->ops->put_char(tty, ch);
3074 return tty->ops->write(tty, &ch, 1);
3075}
3076EXPORT_SYMBOL_GPL(tty_put_char);
3077
3078struct class *tty_class;
3079
3080static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3081 unsigned int index, unsigned int count)
3082{
3083 /* init here, since reused cdevs cause crashes */
3084 cdev_init(&driver->cdevs[index], &tty_fops);
3085 driver->cdevs[index].owner = driver->owner;
3086 return cdev_add(&driver->cdevs[index], dev, count);
3087}
3088
3089/**
3090 * tty_register_device - register a tty device
3091 * @driver: the tty driver that describes the tty device
3092 * @index: the index in the tty driver for this tty device
3093 * @device: a struct device that is associated with this tty device.
3094 * This field is optional, if there is no known struct device
3095 * for this tty device it can be set to NULL safely.
3096 *
3097 * Returns a pointer to the struct device for this tty device
3098 * (or ERR_PTR(-EFOO) on error).
3099 *
3100 * This call is required to be made to register an individual tty device
3101 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3102 * that bit is not set, this function should not be called by a tty
3103 * driver.
3104 *
3105 * Locking: ??
3106 */
3107
3108struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3109 struct device *device)
3110{
3111 return tty_register_device_attr(driver, index, device, NULL, NULL);
3112}
3113EXPORT_SYMBOL(tty_register_device);
3114
3115static void tty_device_create_release(struct device *dev)
3116{
3117 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3118 kfree(dev);
3119}
3120
3121/**
3122 * tty_register_device_attr - register a tty device
3123 * @driver: the tty driver that describes the tty device
3124 * @index: the index in the tty driver for this tty device
3125 * @device: a struct device that is associated with this tty device.
3126 * This field is optional, if there is no known struct device
3127 * for this tty device it can be set to NULL safely.
3128 * @drvdata: Driver data to be set to device.
3129 * @attr_grp: Attribute group to be set on device.
3130 *
3131 * Returns a pointer to the struct device for this tty device
3132 * (or ERR_PTR(-EFOO) on error).
3133 *
3134 * This call is required to be made to register an individual tty device
3135 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3136 * that bit is not set, this function should not be called by a tty
3137 * driver.
3138 *
3139 * Locking: ??
3140 */
3141struct device *tty_register_device_attr(struct tty_driver *driver,
3142 unsigned index, struct device *device,
3143 void *drvdata,
3144 const struct attribute_group **attr_grp)
3145{
3146 char name[64];
3147 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3148 struct device *dev = NULL;
3149 int retval = -ENODEV;
3150 bool cdev = false;
3151
3152 if (index >= driver->num) {
3153 printk(KERN_ERR "Attempt to register invalid tty line number "
3154 " (%d).\n", index);
3155 return ERR_PTR(-EINVAL);
3156 }
3157
3158 if (driver->type == TTY_DRIVER_TYPE_PTY)
3159 pty_line_name(driver, index, name);
3160 else
3161 tty_line_name(driver, index, name);
3162
3163 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3164 retval = tty_cdev_add(driver, devt, index, 1);
3165 if (retval)
3166 goto error;
3167 cdev = true;
3168 }
3169
3170 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3171 if (!dev) {
3172 retval = -ENOMEM;
3173 goto error;
3174 }
3175
3176 dev->devt = devt;
3177 dev->class = tty_class;
3178 dev->parent = device;
3179 dev->release = tty_device_create_release;
3180 dev_set_name(dev, "%s", name);
3181 dev->groups = attr_grp;
3182 dev_set_drvdata(dev, drvdata);
3183
3184 retval = device_register(dev);
3185 if (retval)
3186 goto error;
3187
3188 return dev;
3189
3190error:
3191 put_device(dev);
3192 if (cdev)
3193 cdev_del(&driver->cdevs[index]);
3194 return ERR_PTR(retval);
3195}
3196EXPORT_SYMBOL_GPL(tty_register_device_attr);
3197
3198/**
3199 * tty_unregister_device - unregister a tty device
3200 * @driver: the tty driver that describes the tty device
3201 * @index: the index in the tty driver for this tty device
3202 *
3203 * If a tty device is registered with a call to tty_register_device() then
3204 * this function must be called when the tty device is gone.
3205 *
3206 * Locking: ??
3207 */
3208
3209void tty_unregister_device(struct tty_driver *driver, unsigned index)
3210{
3211 device_destroy(tty_class,
3212 MKDEV(driver->major, driver->minor_start) + index);
3213 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3214 cdev_del(&driver->cdevs[index]);
3215}
3216EXPORT_SYMBOL(tty_unregister_device);
3217
3218/**
3219 * __tty_alloc_driver -- allocate tty driver
3220 * @lines: count of lines this driver can handle at most
3221 * @owner: module which is repsonsible for this driver
3222 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3223 *
3224 * This should not be called directly, some of the provided macros should be
3225 * used instead. Use IS_ERR and friends on @retval.
3226 */
3227struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3228 unsigned long flags)
3229{
3230 struct tty_driver *driver;
3231 unsigned int cdevs = 1;
3232 int err;
3233
3234 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3235 return ERR_PTR(-EINVAL);
3236
3237 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3238 if (!driver)
3239 return ERR_PTR(-ENOMEM);
3240
3241 kref_init(&driver->kref);
3242 driver->magic = TTY_DRIVER_MAGIC;
3243 driver->num = lines;
3244 driver->owner = owner;
3245 driver->flags = flags;
3246
3247 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3248 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3249 GFP_KERNEL);
3250 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3251 GFP_KERNEL);
3252 if (!driver->ttys || !driver->termios) {
3253 err = -ENOMEM;
3254 goto err_free_all;
3255 }
3256 }
3257
3258 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3259 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3260 GFP_KERNEL);
3261 if (!driver->ports) {
3262 err = -ENOMEM;
3263 goto err_free_all;
3264 }
3265 cdevs = lines;
3266 }
3267
3268 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3269 if (!driver->cdevs) {
3270 err = -ENOMEM;
3271 goto err_free_all;
3272 }
3273
3274 return driver;
3275err_free_all:
3276 kfree(driver->ports);
3277 kfree(driver->ttys);
3278 kfree(driver->termios);
3279 kfree(driver);
3280 return ERR_PTR(err);
3281}
3282EXPORT_SYMBOL(__tty_alloc_driver);
3283
3284static void destruct_tty_driver(struct kref *kref)
3285{
3286 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3287 int i;
3288 struct ktermios *tp;
3289
3290 if (driver->flags & TTY_DRIVER_INSTALLED) {
3291 /*
3292 * Free the termios and termios_locked structures because
3293 * we don't want to get memory leaks when modular tty
3294 * drivers are removed from the kernel.
3295 */
3296 for (i = 0; i < driver->num; i++) {
3297 tp = driver->termios[i];
3298 if (tp) {
3299 driver->termios[i] = NULL;
3300 kfree(tp);
3301 }
3302 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3303 tty_unregister_device(driver, i);
3304 }
3305 proc_tty_unregister_driver(driver);
3306 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3307 cdev_del(&driver->cdevs[0]);
3308 }
3309 kfree(driver->cdevs);
3310 kfree(driver->ports);
3311 kfree(driver->termios);
3312 kfree(driver->ttys);
3313 kfree(driver);
3314}
3315
3316void tty_driver_kref_put(struct tty_driver *driver)
3317{
3318 kref_put(&driver->kref, destruct_tty_driver);
3319}
3320EXPORT_SYMBOL(tty_driver_kref_put);
3321
3322void tty_set_operations(struct tty_driver *driver,
3323 const struct tty_operations *op)
3324{
3325 driver->ops = op;
3326};
3327EXPORT_SYMBOL(tty_set_operations);
3328
3329void put_tty_driver(struct tty_driver *d)
3330{
3331 tty_driver_kref_put(d);
3332}
3333EXPORT_SYMBOL(put_tty_driver);
3334
3335/*
3336 * Called by a tty driver to register itself.
3337 */
3338int tty_register_driver(struct tty_driver *driver)
3339{
3340 int error;
3341 int i;
3342 dev_t dev;
3343 struct device *d;
3344
3345 if (!driver->major) {
3346 error = alloc_chrdev_region(&dev, driver->minor_start,
3347 driver->num, driver->name);
3348 if (!error) {
3349 driver->major = MAJOR(dev);
3350 driver->minor_start = MINOR(dev);
3351 }
3352 } else {
3353 dev = MKDEV(driver->major, driver->minor_start);
3354 error = register_chrdev_region(dev, driver->num, driver->name);
3355 }
3356 if (error < 0)
3357 goto err;
3358
3359 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3360 error = tty_cdev_add(driver, dev, 0, driver->num);
3361 if (error)
3362 goto err_unreg_char;
3363 }
3364
3365 mutex_lock(&tty_mutex);
3366 list_add(&driver->tty_drivers, &tty_drivers);
3367 mutex_unlock(&tty_mutex);
3368
3369 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3370 for (i = 0; i < driver->num; i++) {
3371 d = tty_register_device(driver, i, NULL);
3372 if (IS_ERR(d)) {
3373 error = PTR_ERR(d);
3374 goto err_unreg_devs;
3375 }
3376 }
3377 }
3378 proc_tty_register_driver(driver);
3379 driver->flags |= TTY_DRIVER_INSTALLED;
3380 return 0;
3381
3382err_unreg_devs:
3383 for (i--; i >= 0; i--)
3384 tty_unregister_device(driver, i);
3385
3386 mutex_lock(&tty_mutex);
3387 list_del(&driver->tty_drivers);
3388 mutex_unlock(&tty_mutex);
3389
3390err_unreg_char:
3391 unregister_chrdev_region(dev, driver->num);
3392err:
3393 return error;
3394}
3395EXPORT_SYMBOL(tty_register_driver);
3396
3397/*
3398 * Called by a tty driver to unregister itself.
3399 */
3400int tty_unregister_driver(struct tty_driver *driver)
3401{
3402#if 0
3403 /* FIXME */
3404 if (driver->refcount)
3405 return -EBUSY;
3406#endif
3407 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3408 driver->num);
3409 mutex_lock(&tty_mutex);
3410 list_del(&driver->tty_drivers);
3411 mutex_unlock(&tty_mutex);
3412 return 0;
3413}
3414
3415EXPORT_SYMBOL(tty_unregister_driver);
3416
3417dev_t tty_devnum(struct tty_struct *tty)
3418{
3419 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3420}
3421EXPORT_SYMBOL(tty_devnum);
3422
3423void proc_clear_tty(struct task_struct *p)
3424{
3425 unsigned long flags;
3426 struct tty_struct *tty;
3427 spin_lock_irqsave(&p->sighand->siglock, flags);
3428 tty = p->signal->tty;
3429 p->signal->tty = NULL;
3430 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3431 tty_kref_put(tty);
3432}
3433
3434/* Called under the sighand lock */
3435
3436static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3437{
3438 if (tty) {
3439 unsigned long flags;
3440 /* We should not have a session or pgrp to put here but.... */
3441 spin_lock_irqsave(&tty->ctrl_lock, flags);
3442 put_pid(tty->session);
3443 put_pid(tty->pgrp);
3444 tty->pgrp = get_pid(task_pgrp(tsk));
3445 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3446 tty->session = get_pid(task_session(tsk));
3447 if (tsk->signal->tty) {
3448 printk(KERN_DEBUG "tty not NULL!!\n");
3449 tty_kref_put(tsk->signal->tty);
3450 }
3451 }
3452 put_pid(tsk->signal->tty_old_pgrp);
3453 tsk->signal->tty = tty_kref_get(tty);
3454 tsk->signal->tty_old_pgrp = NULL;
3455}
3456
3457static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3458{
3459 spin_lock_irq(&tsk->sighand->siglock);
3460 __proc_set_tty(tsk, tty);
3461 spin_unlock_irq(&tsk->sighand->siglock);
3462}
3463
3464struct tty_struct *get_current_tty(void)
3465{
3466 struct tty_struct *tty;
3467 unsigned long flags;
3468
3469 spin_lock_irqsave(¤t->sighand->siglock, flags);
3470 tty = tty_kref_get(current->signal->tty);
3471 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3472 return tty;
3473}
3474EXPORT_SYMBOL_GPL(get_current_tty);
3475
3476void tty_default_fops(struct file_operations *fops)
3477{
3478 *fops = tty_fops;
3479}
3480
3481/*
3482 * Initialize the console device. This is called *early*, so
3483 * we can't necessarily depend on lots of kernel help here.
3484 * Just do some early initializations, and do the complex setup
3485 * later.
3486 */
3487void __init console_init(void)
3488{
3489 initcall_t *call;
3490
3491 /* Setup the default TTY line discipline. */
3492 tty_ldisc_begin();
3493
3494 /*
3495 * set up the console device so that later boot sequences can
3496 * inform about problems etc..
3497 */
3498 call = __con_initcall_start;
3499 while (call < __con_initcall_end) {
3500 (*call)();
3501 call++;
3502 }
3503}
3504
3505static char *tty_devnode(struct device *dev, umode_t *mode)
3506{
3507 if (!mode)
3508 return NULL;
3509 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3510 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3511 *mode = 0666;
3512 return NULL;
3513}
3514
3515static int __init tty_class_init(void)
3516{
3517 tty_class = class_create(THIS_MODULE, "tty");
3518 if (IS_ERR(tty_class))
3519 return PTR_ERR(tty_class);
3520 tty_class->devnode = tty_devnode;
3521 return 0;
3522}
3523
3524postcore_initcall(tty_class_init);
3525
3526/* 3/2004 jmc: why do these devices exist? */
3527static struct cdev tty_cdev, console_cdev;
3528
3529static ssize_t show_cons_active(struct device *dev,
3530 struct device_attribute *attr, char *buf)
3531{
3532 struct console *cs[16];
3533 int i = 0;
3534 struct console *c;
3535 ssize_t count = 0;
3536
3537 console_lock();
3538 for_each_console(c) {
3539 if (!c->device)
3540 continue;
3541 if (!c->write)
3542 continue;
3543 if ((c->flags & CON_ENABLED) == 0)
3544 continue;
3545 cs[i++] = c;
3546 if (i >= ARRAY_SIZE(cs))
3547 break;
3548 }
3549 while (i--) {
3550 int index = cs[i]->index;
3551 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3552
3553 /* don't resolve tty0 as some programs depend on it */
3554 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3555 count += tty_line_name(drv, index, buf + count);
3556 else
3557 count += sprintf(buf + count, "%s%d",
3558 cs[i]->name, cs[i]->index);
3559
3560 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3561 }
3562 console_unlock();
3563
3564 return count;
3565}
3566static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3567
3568static struct device *consdev;
3569
3570void console_sysfs_notify(void)
3571{
3572 if (consdev)
3573 sysfs_notify(&consdev->kobj, NULL, "active");
3574}
3575
3576/*
3577 * Ok, now we can initialize the rest of the tty devices and can count
3578 * on memory allocations, interrupts etc..
3579 */
3580int __init tty_init(void)
3581{
3582 cdev_init(&tty_cdev, &tty_fops);
3583 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3584 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3585 panic("Couldn't register /dev/tty driver\n");
3586 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3587
3588 cdev_init(&console_cdev, &console_fops);
3589 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3590 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3591 panic("Couldn't register /dev/console driver\n");
3592 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3593 "console");
3594 if (IS_ERR(consdev))
3595 consdev = NULL;
3596 else
3597 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3598
3599#ifdef CONFIG_VT
3600 vty_init(&console_fops);
3601#endif
3602 return 0;
3603}
3604