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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
105#include <linux/kbd_kern.h>
106#include <linux/vt_kern.h>
107#include <linux/selection.h>
108
109#include <linux/kmod.h>
110#include <linux/nsproxy.h>
111#include "tty.h"
112
113#undef TTY_DEBUG_HANGUP
114#ifdef TTY_DEBUG_HANGUP
115# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
116#else
117# define tty_debug_hangup(tty, f, args...) do { } while (0)
118#endif
119
120#define TTY_PARANOIA_CHECK 1
121#define CHECK_TTY_COUNT 1
122
123struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
124 .c_iflag = ICRNL | IXON,
125 .c_oflag = OPOST | ONLCR,
126 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
127 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
128 ECHOCTL | ECHOKE | IEXTEN,
129 .c_cc = INIT_C_CC,
130 .c_ispeed = 38400,
131 .c_ospeed = 38400,
132 /* .c_line = N_TTY, */
133};
134EXPORT_SYMBOL(tty_std_termios);
135
136/* This list gets poked at by procfs and various bits of boot up code. This
137 * could do with some rationalisation such as pulling the tty proc function
138 * into this file.
139 */
140
141LIST_HEAD(tty_drivers); /* linked list of tty drivers */
142
143/* Mutex to protect creating and releasing a tty */
144DEFINE_MUTEX(tty_mutex);
145
146static ssize_t tty_read(struct kiocb *, struct iov_iter *);
147static ssize_t tty_write(struct kiocb *, struct iov_iter *);
148static __poll_t tty_poll(struct file *, poll_table *);
149static int tty_open(struct inode *, struct file *);
150#ifdef CONFIG_COMPAT
151static long tty_compat_ioctl(struct file *file, unsigned int cmd,
152 unsigned long arg);
153#else
154#define tty_compat_ioctl NULL
155#endif
156static int __tty_fasync(int fd, struct file *filp, int on);
157static int tty_fasync(int fd, struct file *filp, int on);
158static void release_tty(struct tty_struct *tty, int idx);
159
160/**
161 * free_tty_struct - free a disused tty
162 * @tty: tty struct to free
163 *
164 * Free the write buffers, tty queue and tty memory itself.
165 *
166 * Locking: none. Must be called after tty is definitely unused
167 */
168static void free_tty_struct(struct tty_struct *tty)
169{
170 tty_ldisc_deinit(tty);
171 put_device(tty->dev);
172 kvfree(tty->write_buf);
173 kfree(tty);
174}
175
176static inline struct tty_struct *file_tty(struct file *file)
177{
178 return ((struct tty_file_private *)file->private_data)->tty;
179}
180
181int tty_alloc_file(struct file *file)
182{
183 struct tty_file_private *priv;
184
185 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
186 if (!priv)
187 return -ENOMEM;
188
189 file->private_data = priv;
190
191 return 0;
192}
193
194/* Associate a new file with the tty structure */
195void tty_add_file(struct tty_struct *tty, struct file *file)
196{
197 struct tty_file_private *priv = file->private_data;
198
199 priv->tty = tty;
200 priv->file = file;
201
202 spin_lock(&tty->files_lock);
203 list_add(&priv->list, &tty->tty_files);
204 spin_unlock(&tty->files_lock);
205}
206
207/**
208 * tty_free_file - free file->private_data
209 * @file: to free private_data of
210 *
211 * This shall be used only for fail path handling when tty_add_file was not
212 * called yet.
213 */
214void tty_free_file(struct file *file)
215{
216 struct tty_file_private *priv = file->private_data;
217
218 file->private_data = NULL;
219 kfree(priv);
220}
221
222/* Delete file from its tty */
223static void tty_del_file(struct file *file)
224{
225 struct tty_file_private *priv = file->private_data;
226 struct tty_struct *tty = priv->tty;
227
228 spin_lock(&tty->files_lock);
229 list_del(&priv->list);
230 spin_unlock(&tty->files_lock);
231 tty_free_file(file);
232}
233
234/**
235 * tty_name - return tty naming
236 * @tty: tty structure
237 *
238 * Convert a tty structure into a name. The name reflects the kernel naming
239 * policy and if udev is in use may not reflect user space
240 *
241 * Locking: none
242 */
243const char *tty_name(const struct tty_struct *tty)
244{
245 if (!tty) /* Hmm. NULL pointer. That's fun. */
246 return "NULL tty";
247 return tty->name;
248}
249EXPORT_SYMBOL(tty_name);
250
251const char *tty_driver_name(const struct tty_struct *tty)
252{
253 if (!tty || !tty->driver)
254 return "";
255 return tty->driver->name;
256}
257
258static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
259 const char *routine)
260{
261#ifdef TTY_PARANOIA_CHECK
262 if (!tty) {
263 pr_warn("(%d:%d): %s: NULL tty\n",
264 imajor(inode), iminor(inode), routine);
265 return 1;
266 }
267#endif
268 return 0;
269}
270
271/* Caller must hold tty_lock */
272static int check_tty_count(struct tty_struct *tty, const char *routine)
273{
274#ifdef CHECK_TTY_COUNT
275 struct list_head *p;
276 int count = 0, kopen_count = 0;
277
278 spin_lock(&tty->files_lock);
279 list_for_each(p, &tty->tty_files) {
280 count++;
281 }
282 spin_unlock(&tty->files_lock);
283 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
284 tty->driver->subtype == PTY_TYPE_SLAVE &&
285 tty->link && tty->link->count)
286 count++;
287 if (tty_port_kopened(tty->port))
288 kopen_count++;
289 if (tty->count != (count + kopen_count)) {
290 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
291 routine, tty->count, count, kopen_count);
292 return (count + kopen_count);
293 }
294#endif
295 return 0;
296}
297
298/**
299 * get_tty_driver - find device of a tty
300 * @device: device identifier
301 * @index: returns the index of the tty
302 *
303 * This routine returns a tty driver structure, given a device number and also
304 * passes back the index number.
305 *
306 * Locking: caller must hold tty_mutex
307 */
308static struct tty_driver *get_tty_driver(dev_t device, int *index)
309{
310 struct tty_driver *p;
311
312 list_for_each_entry(p, &tty_drivers, tty_drivers) {
313 dev_t base = MKDEV(p->major, p->minor_start);
314
315 if (device < base || device >= base + p->num)
316 continue;
317 *index = device - base;
318 return tty_driver_kref_get(p);
319 }
320 return NULL;
321}
322
323/**
324 * tty_dev_name_to_number - return dev_t for device name
325 * @name: user space name of device under /dev
326 * @number: pointer to dev_t that this function will populate
327 *
328 * This function converts device names like ttyS0 or ttyUSB1 into dev_t like
329 * (4, 64) or (188, 1). If no corresponding driver is registered then the
330 * function returns -%ENODEV.
331 *
332 * Locking: this acquires tty_mutex to protect the tty_drivers list from
333 * being modified while we are traversing it, and makes sure to
334 * release it before exiting.
335 */
336int tty_dev_name_to_number(const char *name, dev_t *number)
337{
338 struct tty_driver *p;
339 int ret;
340 int index, prefix_length = 0;
341 const char *str;
342
343 for (str = name; *str && !isdigit(*str); str++)
344 ;
345
346 if (!*str)
347 return -EINVAL;
348
349 ret = kstrtoint(str, 10, &index);
350 if (ret)
351 return ret;
352
353 prefix_length = str - name;
354 mutex_lock(&tty_mutex);
355
356 list_for_each_entry(p, &tty_drivers, tty_drivers)
357 if (prefix_length == strlen(p->name) && strncmp(name,
358 p->name, prefix_length) == 0) {
359 if (index < p->num) {
360 *number = MKDEV(p->major, p->minor_start + index);
361 goto out;
362 }
363 }
364
365 /* if here then driver wasn't found */
366 ret = -ENODEV;
367out:
368 mutex_unlock(&tty_mutex);
369 return ret;
370}
371EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
372
373#ifdef CONFIG_CONSOLE_POLL
374
375/**
376 * tty_find_polling_driver - find device of a polled tty
377 * @name: name string to match
378 * @line: pointer to resulting tty line nr
379 *
380 * This routine returns a tty driver structure, given a name and the condition
381 * that the tty driver is capable of polled operation.
382 */
383struct tty_driver *tty_find_polling_driver(char *name, int *line)
384{
385 struct tty_driver *p, *res = NULL;
386 int tty_line = 0;
387 int len;
388 char *str, *stp;
389
390 for (str = name; *str; str++)
391 if ((*str >= '0' && *str <= '9') || *str == ',')
392 break;
393 if (!*str)
394 return NULL;
395
396 len = str - name;
397 tty_line = simple_strtoul(str, &str, 10);
398
399 mutex_lock(&tty_mutex);
400 /* Search through the tty devices to look for a match */
401 list_for_each_entry(p, &tty_drivers, tty_drivers) {
402 if (!len || strncmp(name, p->name, len) != 0)
403 continue;
404 stp = str;
405 if (*stp == ',')
406 stp++;
407 if (*stp == '\0')
408 stp = NULL;
409
410 if (tty_line >= 0 && tty_line < p->num && p->ops &&
411 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
412 res = tty_driver_kref_get(p);
413 *line = tty_line;
414 break;
415 }
416 }
417 mutex_unlock(&tty_mutex);
418
419 return res;
420}
421EXPORT_SYMBOL_GPL(tty_find_polling_driver);
422#endif
423
424static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to)
425{
426 return 0;
427}
428
429static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
430{
431 return -EIO;
432}
433
434/* No kernel lock held - none needed ;) */
435static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
436{
437 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
438}
439
440static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
441 unsigned long arg)
442{
443 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
444}
445
446static long hung_up_tty_compat_ioctl(struct file *file,
447 unsigned int cmd, unsigned long arg)
448{
449 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
450}
451
452static int hung_up_tty_fasync(int fd, struct file *file, int on)
453{
454 return -ENOTTY;
455}
456
457static void tty_show_fdinfo(struct seq_file *m, struct file *file)
458{
459 struct tty_struct *tty = file_tty(file);
460
461 if (tty && tty->ops && tty->ops->show_fdinfo)
462 tty->ops->show_fdinfo(tty, m);
463}
464
465static const struct file_operations tty_fops = {
466 .llseek = no_llseek,
467 .read_iter = tty_read,
468 .write_iter = tty_write,
469 .splice_read = generic_file_splice_read,
470 .splice_write = iter_file_splice_write,
471 .poll = tty_poll,
472 .unlocked_ioctl = tty_ioctl,
473 .compat_ioctl = tty_compat_ioctl,
474 .open = tty_open,
475 .release = tty_release,
476 .fasync = tty_fasync,
477 .show_fdinfo = tty_show_fdinfo,
478};
479
480static const struct file_operations console_fops = {
481 .llseek = no_llseek,
482 .read_iter = tty_read,
483 .write_iter = redirected_tty_write,
484 .splice_read = generic_file_splice_read,
485 .splice_write = iter_file_splice_write,
486 .poll = tty_poll,
487 .unlocked_ioctl = tty_ioctl,
488 .compat_ioctl = tty_compat_ioctl,
489 .open = tty_open,
490 .release = tty_release,
491 .fasync = tty_fasync,
492};
493
494static const struct file_operations hung_up_tty_fops = {
495 .llseek = no_llseek,
496 .read_iter = hung_up_tty_read,
497 .write_iter = hung_up_tty_write,
498 .poll = hung_up_tty_poll,
499 .unlocked_ioctl = hung_up_tty_ioctl,
500 .compat_ioctl = hung_up_tty_compat_ioctl,
501 .release = tty_release,
502 .fasync = hung_up_tty_fasync,
503};
504
505static DEFINE_SPINLOCK(redirect_lock);
506static struct file *redirect;
507
508/**
509 * tty_wakeup - request more data
510 * @tty: terminal
511 *
512 * Internal and external helper for wakeups of tty. This function informs the
513 * line discipline if present that the driver is ready to receive more output
514 * data.
515 */
516void tty_wakeup(struct tty_struct *tty)
517{
518 struct tty_ldisc *ld;
519
520 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
521 ld = tty_ldisc_ref(tty);
522 if (ld) {
523 if (ld->ops->write_wakeup)
524 ld->ops->write_wakeup(tty);
525 tty_ldisc_deref(ld);
526 }
527 }
528 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
529}
530EXPORT_SYMBOL_GPL(tty_wakeup);
531
532/**
533 * tty_release_redirect - Release a redirect on a pty if present
534 * @tty: tty device
535 *
536 * This is available to the pty code so if the master closes, if the slave is a
537 * redirect it can release the redirect.
538 */
539static struct file *tty_release_redirect(struct tty_struct *tty)
540{
541 struct file *f = NULL;
542
543 spin_lock(&redirect_lock);
544 if (redirect && file_tty(redirect) == tty) {
545 f = redirect;
546 redirect = NULL;
547 }
548 spin_unlock(&redirect_lock);
549
550 return f;
551}
552
553/**
554 * __tty_hangup - actual handler for hangup events
555 * @tty: tty device
556 * @exit_session: if non-zero, signal all foreground group processes
557 *
558 * This can be called by a "kworker" kernel thread. That is process synchronous
559 * but doesn't hold any locks, so we need to make sure we have the appropriate
560 * locks for what we're doing.
561 *
562 * The hangup event clears any pending redirections onto the hung up device. It
563 * ensures future writes will error and it does the needed line discipline
564 * hangup and signal delivery. The tty object itself remains intact.
565 *
566 * Locking:
567 * * BTM
568 *
569 * * redirect lock for undoing redirection
570 * * file list lock for manipulating list of ttys
571 * * tty_ldiscs_lock from called functions
572 * * termios_rwsem resetting termios data
573 * * tasklist_lock to walk task list for hangup event
574 *
575 * * ->siglock to protect ->signal/->sighand
576 *
577 */
578static void __tty_hangup(struct tty_struct *tty, int exit_session)
579{
580 struct file *cons_filp = NULL;
581 struct file *filp, *f;
582 struct tty_file_private *priv;
583 int closecount = 0, n;
584 int refs;
585
586 if (!tty)
587 return;
588
589 f = tty_release_redirect(tty);
590
591 tty_lock(tty);
592
593 if (test_bit(TTY_HUPPED, &tty->flags)) {
594 tty_unlock(tty);
595 return;
596 }
597
598 /*
599 * Some console devices aren't actually hung up for technical and
600 * historical reasons, which can lead to indefinite interruptible
601 * sleep in n_tty_read(). The following explicitly tells
602 * n_tty_read() to abort readers.
603 */
604 set_bit(TTY_HUPPING, &tty->flags);
605
606 /* inuse_filps is protected by the single tty lock,
607 * this really needs to change if we want to flush the
608 * workqueue with the lock held.
609 */
610 check_tty_count(tty, "tty_hangup");
611
612 spin_lock(&tty->files_lock);
613 /* This breaks for file handles being sent over AF_UNIX sockets ? */
614 list_for_each_entry(priv, &tty->tty_files, list) {
615 filp = priv->file;
616 if (filp->f_op->write_iter == redirected_tty_write)
617 cons_filp = filp;
618 if (filp->f_op->write_iter != tty_write)
619 continue;
620 closecount++;
621 __tty_fasync(-1, filp, 0); /* can't block */
622 filp->f_op = &hung_up_tty_fops;
623 }
624 spin_unlock(&tty->files_lock);
625
626 refs = tty_signal_session_leader(tty, exit_session);
627 /* Account for the p->signal references we killed */
628 while (refs--)
629 tty_kref_put(tty);
630
631 tty_ldisc_hangup(tty, cons_filp != NULL);
632
633 spin_lock_irq(&tty->ctrl.lock);
634 clear_bit(TTY_THROTTLED, &tty->flags);
635 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
636 put_pid(tty->ctrl.session);
637 put_pid(tty->ctrl.pgrp);
638 tty->ctrl.session = NULL;
639 tty->ctrl.pgrp = NULL;
640 tty->ctrl.pktstatus = 0;
641 spin_unlock_irq(&tty->ctrl.lock);
642
643 /*
644 * If one of the devices matches a console pointer, we
645 * cannot just call hangup() because that will cause
646 * tty->count and state->count to go out of sync.
647 * So we just call close() the right number of times.
648 */
649 if (cons_filp) {
650 if (tty->ops->close)
651 for (n = 0; n < closecount; n++)
652 tty->ops->close(tty, cons_filp);
653 } else if (tty->ops->hangup)
654 tty->ops->hangup(tty);
655 /*
656 * We don't want to have driver/ldisc interactions beyond the ones
657 * we did here. The driver layer expects no calls after ->hangup()
658 * from the ldisc side, which is now guaranteed.
659 */
660 set_bit(TTY_HUPPED, &tty->flags);
661 clear_bit(TTY_HUPPING, &tty->flags);
662 tty_unlock(tty);
663
664 if (f)
665 fput(f);
666}
667
668static void do_tty_hangup(struct work_struct *work)
669{
670 struct tty_struct *tty =
671 container_of(work, struct tty_struct, hangup_work);
672
673 __tty_hangup(tty, 0);
674}
675
676/**
677 * tty_hangup - trigger a hangup event
678 * @tty: tty to hangup
679 *
680 * A carrier loss (virtual or otherwise) has occurred on @tty. Schedule a
681 * hangup sequence to run after this event.
682 */
683void tty_hangup(struct tty_struct *tty)
684{
685 tty_debug_hangup(tty, "hangup\n");
686 schedule_work(&tty->hangup_work);
687}
688EXPORT_SYMBOL(tty_hangup);
689
690/**
691 * tty_vhangup - process vhangup
692 * @tty: tty to hangup
693 *
694 * The user has asked via system call for the terminal to be hung up. We do
695 * this synchronously so that when the syscall returns the process is complete.
696 * That guarantee is necessary for security reasons.
697 */
698void tty_vhangup(struct tty_struct *tty)
699{
700 tty_debug_hangup(tty, "vhangup\n");
701 __tty_hangup(tty, 0);
702}
703EXPORT_SYMBOL(tty_vhangup);
704
705
706/**
707 * tty_vhangup_self - process vhangup for own ctty
708 *
709 * Perform a vhangup on the current controlling tty
710 */
711void tty_vhangup_self(void)
712{
713 struct tty_struct *tty;
714
715 tty = get_current_tty();
716 if (tty) {
717 tty_vhangup(tty);
718 tty_kref_put(tty);
719 }
720}
721
722/**
723 * tty_vhangup_session - hangup session leader exit
724 * @tty: tty to hangup
725 *
726 * The session leader is exiting and hanging up its controlling terminal.
727 * Every process in the foreground process group is signalled %SIGHUP.
728 *
729 * We do this synchronously so that when the syscall returns the process is
730 * complete. That guarantee is necessary for security reasons.
731 */
732void tty_vhangup_session(struct tty_struct *tty)
733{
734 tty_debug_hangup(tty, "session hangup\n");
735 __tty_hangup(tty, 1);
736}
737
738/**
739 * tty_hung_up_p - was tty hung up
740 * @filp: file pointer of tty
741 *
742 * Return: true if the tty has been subject to a vhangup or a carrier loss
743 */
744int tty_hung_up_p(struct file *filp)
745{
746 return (filp && filp->f_op == &hung_up_tty_fops);
747}
748EXPORT_SYMBOL(tty_hung_up_p);
749
750void __stop_tty(struct tty_struct *tty)
751{
752 if (tty->flow.stopped)
753 return;
754 tty->flow.stopped = true;
755 if (tty->ops->stop)
756 tty->ops->stop(tty);
757}
758
759/**
760 * stop_tty - propagate flow control
761 * @tty: tty to stop
762 *
763 * Perform flow control to the driver. May be called on an already stopped
764 * device and will not re-call the &tty_driver->stop() method.
765 *
766 * This functionality is used by both the line disciplines for halting incoming
767 * flow and by the driver. It may therefore be called from any context, may be
768 * under the tty %atomic_write_lock but not always.
769 *
770 * Locking:
771 * flow.lock
772 */
773void stop_tty(struct tty_struct *tty)
774{
775 unsigned long flags;
776
777 spin_lock_irqsave(&tty->flow.lock, flags);
778 __stop_tty(tty);
779 spin_unlock_irqrestore(&tty->flow.lock, flags);
780}
781EXPORT_SYMBOL(stop_tty);
782
783void __start_tty(struct tty_struct *tty)
784{
785 if (!tty->flow.stopped || tty->flow.tco_stopped)
786 return;
787 tty->flow.stopped = false;
788 if (tty->ops->start)
789 tty->ops->start(tty);
790 tty_wakeup(tty);
791}
792
793/**
794 * start_tty - propagate flow control
795 * @tty: tty to start
796 *
797 * Start a tty that has been stopped if at all possible. If @tty was previously
798 * stopped and is now being started, the &tty_driver->start() method is invoked
799 * and the line discipline woken.
800 *
801 * Locking:
802 * flow.lock
803 */
804void start_tty(struct tty_struct *tty)
805{
806 unsigned long flags;
807
808 spin_lock_irqsave(&tty->flow.lock, flags);
809 __start_tty(tty);
810 spin_unlock_irqrestore(&tty->flow.lock, flags);
811}
812EXPORT_SYMBOL(start_tty);
813
814static void tty_update_time(struct timespec64 *time)
815{
816 time64_t sec = ktime_get_real_seconds();
817
818 /*
819 * We only care if the two values differ in anything other than the
820 * lower three bits (i.e every 8 seconds). If so, then we can update
821 * the time of the tty device, otherwise it could be construded as a
822 * security leak to let userspace know the exact timing of the tty.
823 */
824 if ((sec ^ time->tv_sec) & ~7)
825 time->tv_sec = sec;
826}
827
828/*
829 * Iterate on the ldisc ->read() function until we've gotten all
830 * the data the ldisc has for us.
831 *
832 * The "cookie" is something that the ldisc read function can fill
833 * in to let us know that there is more data to be had.
834 *
835 * We promise to continue to call the ldisc until it stops returning
836 * data or clears the cookie. The cookie may be something that the
837 * ldisc maintains state for and needs to free.
838 */
839static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
840 struct file *file, struct iov_iter *to)
841{
842 int retval = 0;
843 void *cookie = NULL;
844 unsigned long offset = 0;
845 char kernel_buf[64];
846 size_t count = iov_iter_count(to);
847
848 do {
849 int size, copied;
850
851 size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count;
852 size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
853 if (!size)
854 break;
855
856 if (size < 0) {
857 /* Did we have an earlier error (ie -EFAULT)? */
858 if (retval)
859 break;
860 retval = size;
861
862 /*
863 * -EOVERFLOW means we didn't have enough space
864 * for a whole packet, and we shouldn't return
865 * a partial result.
866 */
867 if (retval == -EOVERFLOW)
868 offset = 0;
869 break;
870 }
871
872 copied = copy_to_iter(kernel_buf, size, to);
873 offset += copied;
874 count -= copied;
875
876 /*
877 * If the user copy failed, we still need to do another ->read()
878 * call if we had a cookie to let the ldisc clear up.
879 *
880 * But make sure size is zeroed.
881 */
882 if (unlikely(copied != size)) {
883 count = 0;
884 retval = -EFAULT;
885 }
886 } while (cookie);
887
888 /* We always clear tty buffer in case they contained passwords */
889 memzero_explicit(kernel_buf, sizeof(kernel_buf));
890 return offset ? offset : retval;
891}
892
893
894/**
895 * tty_read - read method for tty device files
896 * @iocb: kernel I/O control block
897 * @to: destination for the data read
898 *
899 * Perform the read system call function on this terminal device. Checks
900 * for hung up devices before calling the line discipline method.
901 *
902 * Locking:
903 * Locks the line discipline internally while needed. Multiple read calls
904 * may be outstanding in parallel.
905 */
906static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
907{
908 int i;
909 struct file *file = iocb->ki_filp;
910 struct inode *inode = file_inode(file);
911 struct tty_struct *tty = file_tty(file);
912 struct tty_ldisc *ld;
913
914 if (tty_paranoia_check(tty, inode, "tty_read"))
915 return -EIO;
916 if (!tty || tty_io_error(tty))
917 return -EIO;
918
919 /* We want to wait for the line discipline to sort out in this
920 * situation.
921 */
922 ld = tty_ldisc_ref_wait(tty);
923 if (!ld)
924 return hung_up_tty_read(iocb, to);
925 i = -EIO;
926 if (ld->ops->read)
927 i = iterate_tty_read(ld, tty, file, to);
928 tty_ldisc_deref(ld);
929
930 if (i > 0)
931 tty_update_time(&inode->i_atime);
932
933 return i;
934}
935
936static void tty_write_unlock(struct tty_struct *tty)
937{
938 mutex_unlock(&tty->atomic_write_lock);
939 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
940}
941
942static int tty_write_lock(struct tty_struct *tty, int ndelay)
943{
944 if (!mutex_trylock(&tty->atomic_write_lock)) {
945 if (ndelay)
946 return -EAGAIN;
947 if (mutex_lock_interruptible(&tty->atomic_write_lock))
948 return -ERESTARTSYS;
949 }
950 return 0;
951}
952
953/*
954 * Split writes up in sane blocksizes to avoid
955 * denial-of-service type attacks
956 */
957static inline ssize_t do_tty_write(
958 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
959 struct tty_struct *tty,
960 struct file *file,
961 struct iov_iter *from)
962{
963 size_t count = iov_iter_count(from);
964 ssize_t ret, written = 0;
965 unsigned int chunk;
966
967 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
968 if (ret < 0)
969 return ret;
970
971 /*
972 * We chunk up writes into a temporary buffer. This
973 * simplifies low-level drivers immensely, since they
974 * don't have locking issues and user mode accesses.
975 *
976 * But if TTY_NO_WRITE_SPLIT is set, we should use a
977 * big chunk-size..
978 *
979 * The default chunk-size is 2kB, because the NTTY
980 * layer has problems with bigger chunks. It will
981 * claim to be able to handle more characters than
982 * it actually does.
983 */
984 chunk = 2048;
985 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
986 chunk = 65536;
987 if (count < chunk)
988 chunk = count;
989
990 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
991 if (tty->write_cnt < chunk) {
992 unsigned char *buf_chunk;
993
994 if (chunk < 1024)
995 chunk = 1024;
996
997 buf_chunk = kvmalloc(chunk, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
998 if (!buf_chunk) {
999 ret = -ENOMEM;
1000 goto out;
1001 }
1002 kvfree(tty->write_buf);
1003 tty->write_cnt = chunk;
1004 tty->write_buf = buf_chunk;
1005 }
1006
1007 /* Do the write .. */
1008 for (;;) {
1009 size_t size = count;
1010
1011 if (size > chunk)
1012 size = chunk;
1013
1014 ret = -EFAULT;
1015 if (copy_from_iter(tty->write_buf, size, from) != size)
1016 break;
1017
1018 ret = write(tty, file, tty->write_buf, size);
1019 if (ret <= 0)
1020 break;
1021
1022 written += ret;
1023 if (ret > size)
1024 break;
1025
1026 /* FIXME! Have Al check this! */
1027 if (ret != size)
1028 iov_iter_revert(from, size-ret);
1029
1030 count -= ret;
1031 if (!count)
1032 break;
1033 ret = -ERESTARTSYS;
1034 if (signal_pending(current))
1035 break;
1036 cond_resched();
1037 }
1038 if (written) {
1039 tty_update_time(&file_inode(file)->i_mtime);
1040 ret = written;
1041 }
1042out:
1043 tty_write_unlock(tty);
1044 return ret;
1045}
1046
1047/**
1048 * tty_write_message - write a message to a certain tty, not just the console.
1049 * @tty: the destination tty_struct
1050 * @msg: the message to write
1051 *
1052 * This is used for messages that need to be redirected to a specific tty. We
1053 * don't put it into the syslog queue right now maybe in the future if really
1054 * needed.
1055 *
1056 * We must still hold the BTM and test the CLOSING flag for the moment.
1057 */
1058void tty_write_message(struct tty_struct *tty, char *msg)
1059{
1060 if (tty) {
1061 mutex_lock(&tty->atomic_write_lock);
1062 tty_lock(tty);
1063 if (tty->ops->write && tty->count > 0)
1064 tty->ops->write(tty, msg, strlen(msg));
1065 tty_unlock(tty);
1066 tty_write_unlock(tty);
1067 }
1068}
1069
1070static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_iter *from)
1071{
1072 struct tty_struct *tty = file_tty(file);
1073 struct tty_ldisc *ld;
1074 ssize_t ret;
1075
1076 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1077 return -EIO;
1078 if (!tty || !tty->ops->write || tty_io_error(tty))
1079 return -EIO;
1080 /* Short term debug to catch buggy drivers */
1081 if (tty->ops->write_room == NULL)
1082 tty_err(tty, "missing write_room method\n");
1083 ld = tty_ldisc_ref_wait(tty);
1084 if (!ld)
1085 return hung_up_tty_write(iocb, from);
1086 if (!ld->ops->write)
1087 ret = -EIO;
1088 else
1089 ret = do_tty_write(ld->ops->write, tty, file, from);
1090 tty_ldisc_deref(ld);
1091 return ret;
1092}
1093
1094/**
1095 * tty_write - write method for tty device file
1096 * @iocb: kernel I/O control block
1097 * @from: iov_iter with data to write
1098 *
1099 * Write data to a tty device via the line discipline.
1100 *
1101 * Locking:
1102 * Locks the line discipline as required
1103 * Writes to the tty driver are serialized by the atomic_write_lock
1104 * and are then processed in chunks to the device. The line
1105 * discipline write method will not be invoked in parallel for
1106 * each device.
1107 */
1108static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from)
1109{
1110 return file_tty_write(iocb->ki_filp, iocb, from);
1111}
1112
1113ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter)
1114{
1115 struct file *p = NULL;
1116
1117 spin_lock(&redirect_lock);
1118 if (redirect)
1119 p = get_file(redirect);
1120 spin_unlock(&redirect_lock);
1121
1122 /*
1123 * We know the redirected tty is just another tty, we can
1124 * call file_tty_write() directly with that file pointer.
1125 */
1126 if (p) {
1127 ssize_t res;
1128
1129 res = file_tty_write(p, iocb, iter);
1130 fput(p);
1131 return res;
1132 }
1133 return tty_write(iocb, iter);
1134}
1135
1136/**
1137 * tty_send_xchar - send priority character
1138 * @tty: the tty to send to
1139 * @ch: xchar to send
1140 *
1141 * Send a high priority character to the tty even if stopped.
1142 *
1143 * Locking: none for xchar method, write ordering for write method.
1144 */
1145int tty_send_xchar(struct tty_struct *tty, char ch)
1146{
1147 bool was_stopped = tty->flow.stopped;
1148
1149 if (tty->ops->send_xchar) {
1150 down_read(&tty->termios_rwsem);
1151 tty->ops->send_xchar(tty, ch);
1152 up_read(&tty->termios_rwsem);
1153 return 0;
1154 }
1155
1156 if (tty_write_lock(tty, 0) < 0)
1157 return -ERESTARTSYS;
1158
1159 down_read(&tty->termios_rwsem);
1160 if (was_stopped)
1161 start_tty(tty);
1162 tty->ops->write(tty, &ch, 1);
1163 if (was_stopped)
1164 stop_tty(tty);
1165 up_read(&tty->termios_rwsem);
1166 tty_write_unlock(tty);
1167 return 0;
1168}
1169
1170/**
1171 * pty_line_name - generate name for a pty
1172 * @driver: the tty driver in use
1173 * @index: the minor number
1174 * @p: output buffer of at least 6 bytes
1175 *
1176 * Generate a name from a @driver reference and write it to the output buffer
1177 * @p.
1178 *
1179 * Locking: None
1180 */
1181static void pty_line_name(struct tty_driver *driver, int index, char *p)
1182{
1183 static const char ptychar[] = "pqrstuvwxyzabcde";
1184 int i = index + driver->name_base;
1185 /* ->name is initialized to "ttyp", but "tty" is expected */
1186 sprintf(p, "%s%c%x",
1187 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1188 ptychar[i >> 4 & 0xf], i & 0xf);
1189}
1190
1191/**
1192 * tty_line_name - generate name for a tty
1193 * @driver: the tty driver in use
1194 * @index: the minor number
1195 * @p: output buffer of at least 7 bytes
1196 *
1197 * Generate a name from a @driver reference and write it to the output buffer
1198 * @p.
1199 *
1200 * Locking: None
1201 */
1202static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1203{
1204 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1205 return sprintf(p, "%s", driver->name);
1206 else
1207 return sprintf(p, "%s%d", driver->name,
1208 index + driver->name_base);
1209}
1210
1211/**
1212 * tty_driver_lookup_tty() - find an existing tty, if any
1213 * @driver: the driver for the tty
1214 * @file: file object
1215 * @idx: the minor number
1216 *
1217 * Return: the tty, if found. If not found, return %NULL or ERR_PTR() if the
1218 * driver lookup() method returns an error.
1219 *
1220 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1221 */
1222static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1223 struct file *file, int idx)
1224{
1225 struct tty_struct *tty;
1226
1227 if (driver->ops->lookup)
1228 if (!file)
1229 tty = ERR_PTR(-EIO);
1230 else
1231 tty = driver->ops->lookup(driver, file, idx);
1232 else
1233 tty = driver->ttys[idx];
1234
1235 if (!IS_ERR(tty))
1236 tty_kref_get(tty);
1237 return tty;
1238}
1239
1240/**
1241 * tty_init_termios - helper for termios setup
1242 * @tty: the tty to set up
1243 *
1244 * Initialise the termios structure for this tty. This runs under the
1245 * %tty_mutex currently so we can be relaxed about ordering.
1246 */
1247void tty_init_termios(struct tty_struct *tty)
1248{
1249 struct ktermios *tp;
1250 int idx = tty->index;
1251
1252 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1253 tty->termios = tty->driver->init_termios;
1254 else {
1255 /* Check for lazy saved data */
1256 tp = tty->driver->termios[idx];
1257 if (tp != NULL) {
1258 tty->termios = *tp;
1259 tty->termios.c_line = tty->driver->init_termios.c_line;
1260 } else
1261 tty->termios = tty->driver->init_termios;
1262 }
1263 /* Compatibility until drivers always set this */
1264 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1265 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1266}
1267EXPORT_SYMBOL_GPL(tty_init_termios);
1268
1269/**
1270 * tty_standard_install - usual tty->ops->install
1271 * @driver: the driver for the tty
1272 * @tty: the tty
1273 *
1274 * If the @driver overrides @tty->ops->install, it still can call this function
1275 * to perform the standard install operations.
1276 */
1277int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1278{
1279 tty_init_termios(tty);
1280 tty_driver_kref_get(driver);
1281 tty->count++;
1282 driver->ttys[tty->index] = tty;
1283 return 0;
1284}
1285EXPORT_SYMBOL_GPL(tty_standard_install);
1286
1287/**
1288 * tty_driver_install_tty() - install a tty entry in the driver
1289 * @driver: the driver for the tty
1290 * @tty: the tty
1291 *
1292 * Install a tty object into the driver tables. The @tty->index field will be
1293 * set by the time this is called. This method is responsible for ensuring any
1294 * need additional structures are allocated and configured.
1295 *
1296 * Locking: tty_mutex for now
1297 */
1298static int tty_driver_install_tty(struct tty_driver *driver,
1299 struct tty_struct *tty)
1300{
1301 return driver->ops->install ? driver->ops->install(driver, tty) :
1302 tty_standard_install(driver, tty);
1303}
1304
1305/**
1306 * tty_driver_remove_tty() - remove a tty from the driver tables
1307 * @driver: the driver for the tty
1308 * @tty: tty to remove
1309 *
1310 * Remove a tty object from the driver tables. The tty->index field will be set
1311 * by the time this is called.
1312 *
1313 * Locking: tty_mutex for now
1314 */
1315static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1316{
1317 if (driver->ops->remove)
1318 driver->ops->remove(driver, tty);
1319 else
1320 driver->ttys[tty->index] = NULL;
1321}
1322
1323/**
1324 * tty_reopen() - fast re-open of an open tty
1325 * @tty: the tty to open
1326 *
1327 * Re-opens on master ptys are not allowed and return -%EIO.
1328 *
1329 * Locking: Caller must hold tty_lock
1330 * Return: 0 on success, -errno on error.
1331 */
1332static int tty_reopen(struct tty_struct *tty)
1333{
1334 struct tty_driver *driver = tty->driver;
1335 struct tty_ldisc *ld;
1336 int retval = 0;
1337
1338 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1339 driver->subtype == PTY_TYPE_MASTER)
1340 return -EIO;
1341
1342 if (!tty->count)
1343 return -EAGAIN;
1344
1345 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1346 return -EBUSY;
1347
1348 ld = tty_ldisc_ref_wait(tty);
1349 if (ld) {
1350 tty_ldisc_deref(ld);
1351 } else {
1352 retval = tty_ldisc_lock(tty, 5 * HZ);
1353 if (retval)
1354 return retval;
1355
1356 if (!tty->ldisc)
1357 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1358 tty_ldisc_unlock(tty);
1359 }
1360
1361 if (retval == 0)
1362 tty->count++;
1363
1364 return retval;
1365}
1366
1367/**
1368 * tty_init_dev - initialise a tty device
1369 * @driver: tty driver we are opening a device on
1370 * @idx: device index
1371 *
1372 * Prepare a tty device. This may not be a "new" clean device but could also be
1373 * an active device. The pty drivers require special handling because of this.
1374 *
1375 * Locking:
1376 * The function is called under the tty_mutex, which protects us from the
1377 * tty struct or driver itself going away.
1378 *
1379 * On exit the tty device has the line discipline attached and a reference
1380 * count of 1. If a pair was created for pty/tty use and the other was a pty
1381 * master then it too has a reference count of 1.
1382 *
1383 * WSH 06/09/97: Rewritten to remove races and properly clean up after a failed
1384 * open. The new code protects the open with a mutex, so it's really quite
1385 * straightforward. The mutex locking can probably be relaxed for the (most
1386 * common) case of reopening a tty.
1387 *
1388 * Return: new tty structure
1389 */
1390struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1391{
1392 struct tty_struct *tty;
1393 int retval;
1394
1395 /*
1396 * First time open is complex, especially for PTY devices.
1397 * This code guarantees that either everything succeeds and the
1398 * TTY is ready for operation, or else the table slots are vacated
1399 * and the allocated memory released. (Except that the termios
1400 * may be retained.)
1401 */
1402
1403 if (!try_module_get(driver->owner))
1404 return ERR_PTR(-ENODEV);
1405
1406 tty = alloc_tty_struct(driver, idx);
1407 if (!tty) {
1408 retval = -ENOMEM;
1409 goto err_module_put;
1410 }
1411
1412 tty_lock(tty);
1413 retval = tty_driver_install_tty(driver, tty);
1414 if (retval < 0)
1415 goto err_free_tty;
1416
1417 if (!tty->port)
1418 tty->port = driver->ports[idx];
1419
1420 if (WARN_RATELIMIT(!tty->port,
1421 "%s: %s driver does not set tty->port. This would crash the kernel. Fix the driver!\n",
1422 __func__, tty->driver->name)) {
1423 retval = -EINVAL;
1424 goto err_release_lock;
1425 }
1426
1427 retval = tty_ldisc_lock(tty, 5 * HZ);
1428 if (retval)
1429 goto err_release_lock;
1430 tty->port->itty = tty;
1431
1432 /*
1433 * Structures all installed ... call the ldisc open routines.
1434 * If we fail here just call release_tty to clean up. No need
1435 * to decrement the use counts, as release_tty doesn't care.
1436 */
1437 retval = tty_ldisc_setup(tty, tty->link);
1438 if (retval)
1439 goto err_release_tty;
1440 tty_ldisc_unlock(tty);
1441 /* Return the tty locked so that it cannot vanish under the caller */
1442 return tty;
1443
1444err_free_tty:
1445 tty_unlock(tty);
1446 free_tty_struct(tty);
1447err_module_put:
1448 module_put(driver->owner);
1449 return ERR_PTR(retval);
1450
1451 /* call the tty release_tty routine to clean out this slot */
1452err_release_tty:
1453 tty_ldisc_unlock(tty);
1454 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1455 retval, idx);
1456err_release_lock:
1457 tty_unlock(tty);
1458 release_tty(tty, idx);
1459 return ERR_PTR(retval);
1460}
1461
1462/**
1463 * tty_save_termios() - save tty termios data in driver table
1464 * @tty: tty whose termios data to save
1465 *
1466 * Locking: Caller guarantees serialisation with tty_init_termios().
1467 */
1468void tty_save_termios(struct tty_struct *tty)
1469{
1470 struct ktermios *tp;
1471 int idx = tty->index;
1472
1473 /* If the port is going to reset then it has no termios to save */
1474 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1475 return;
1476
1477 /* Stash the termios data */
1478 tp = tty->driver->termios[idx];
1479 if (tp == NULL) {
1480 tp = kmalloc(sizeof(*tp), GFP_KERNEL);
1481 if (tp == NULL)
1482 return;
1483 tty->driver->termios[idx] = tp;
1484 }
1485 *tp = tty->termios;
1486}
1487EXPORT_SYMBOL_GPL(tty_save_termios);
1488
1489/**
1490 * tty_flush_works - flush all works of a tty/pty pair
1491 * @tty: tty device to flush works for (or either end of a pty pair)
1492 *
1493 * Sync flush all works belonging to @tty (and the 'other' tty).
1494 */
1495static void tty_flush_works(struct tty_struct *tty)
1496{
1497 flush_work(&tty->SAK_work);
1498 flush_work(&tty->hangup_work);
1499 if (tty->link) {
1500 flush_work(&tty->link->SAK_work);
1501 flush_work(&tty->link->hangup_work);
1502 }
1503}
1504
1505/**
1506 * release_one_tty - release tty structure memory
1507 * @work: work of tty we are obliterating
1508 *
1509 * Releases memory associated with a tty structure, and clears out the
1510 * driver table slots. This function is called when a device is no longer
1511 * in use. It also gets called when setup of a device fails.
1512 *
1513 * Locking:
1514 * takes the file list lock internally when working on the list of ttys
1515 * that the driver keeps.
1516 *
1517 * This method gets called from a work queue so that the driver private
1518 * cleanup ops can sleep (needed for USB at least)
1519 */
1520static void release_one_tty(struct work_struct *work)
1521{
1522 struct tty_struct *tty =
1523 container_of(work, struct tty_struct, hangup_work);
1524 struct tty_driver *driver = tty->driver;
1525 struct module *owner = driver->owner;
1526
1527 if (tty->ops->cleanup)
1528 tty->ops->cleanup(tty);
1529
1530 tty_driver_kref_put(driver);
1531 module_put(owner);
1532
1533 spin_lock(&tty->files_lock);
1534 list_del_init(&tty->tty_files);
1535 spin_unlock(&tty->files_lock);
1536
1537 put_pid(tty->ctrl.pgrp);
1538 put_pid(tty->ctrl.session);
1539 free_tty_struct(tty);
1540}
1541
1542static void queue_release_one_tty(struct kref *kref)
1543{
1544 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1545
1546 /* The hangup queue is now free so we can reuse it rather than
1547 * waste a chunk of memory for each port.
1548 */
1549 INIT_WORK(&tty->hangup_work, release_one_tty);
1550 schedule_work(&tty->hangup_work);
1551}
1552
1553/**
1554 * tty_kref_put - release a tty kref
1555 * @tty: tty device
1556 *
1557 * Release a reference to the @tty device and if need be let the kref layer
1558 * destruct the object for us.
1559 */
1560void tty_kref_put(struct tty_struct *tty)
1561{
1562 if (tty)
1563 kref_put(&tty->kref, queue_release_one_tty);
1564}
1565EXPORT_SYMBOL(tty_kref_put);
1566
1567/**
1568 * release_tty - release tty structure memory
1569 * @tty: tty device release
1570 * @idx: index of the tty device release
1571 *
1572 * Release both @tty and a possible linked partner (think pty pair),
1573 * and decrement the refcount of the backing module.
1574 *
1575 * Locking:
1576 * tty_mutex
1577 * takes the file list lock internally when working on the list of ttys
1578 * that the driver keeps.
1579 */
1580static void release_tty(struct tty_struct *tty, int idx)
1581{
1582 /* This should always be true but check for the moment */
1583 WARN_ON(tty->index != idx);
1584 WARN_ON(!mutex_is_locked(&tty_mutex));
1585 if (tty->ops->shutdown)
1586 tty->ops->shutdown(tty);
1587 tty_save_termios(tty);
1588 tty_driver_remove_tty(tty->driver, tty);
1589 if (tty->port)
1590 tty->port->itty = NULL;
1591 if (tty->link)
1592 tty->link->port->itty = NULL;
1593 if (tty->port)
1594 tty_buffer_cancel_work(tty->port);
1595 if (tty->link)
1596 tty_buffer_cancel_work(tty->link->port);
1597
1598 tty_kref_put(tty->link);
1599 tty_kref_put(tty);
1600}
1601
1602/**
1603 * tty_release_checks - check a tty before real release
1604 * @tty: tty to check
1605 * @idx: index of the tty
1606 *
1607 * Performs some paranoid checking before true release of the @tty. This is a
1608 * no-op unless %TTY_PARANOIA_CHECK is defined.
1609 */
1610static int tty_release_checks(struct tty_struct *tty, int idx)
1611{
1612#ifdef TTY_PARANOIA_CHECK
1613 if (idx < 0 || idx >= tty->driver->num) {
1614 tty_debug(tty, "bad idx %d\n", idx);
1615 return -1;
1616 }
1617
1618 /* not much to check for devpts */
1619 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1620 return 0;
1621
1622 if (tty != tty->driver->ttys[idx]) {
1623 tty_debug(tty, "bad driver table[%d] = %p\n",
1624 idx, tty->driver->ttys[idx]);
1625 return -1;
1626 }
1627 if (tty->driver->other) {
1628 struct tty_struct *o_tty = tty->link;
1629
1630 if (o_tty != tty->driver->other->ttys[idx]) {
1631 tty_debug(tty, "bad other table[%d] = %p\n",
1632 idx, tty->driver->other->ttys[idx]);
1633 return -1;
1634 }
1635 if (o_tty->link != tty) {
1636 tty_debug(tty, "bad link = %p\n", o_tty->link);
1637 return -1;
1638 }
1639 }
1640#endif
1641 return 0;
1642}
1643
1644/**
1645 * tty_kclose - closes tty opened by tty_kopen
1646 * @tty: tty device
1647 *
1648 * Performs the final steps to release and free a tty device. It is the same as
1649 * tty_release_struct() except that it also resets %TTY_PORT_KOPENED flag on
1650 * @tty->port.
1651 */
1652void tty_kclose(struct tty_struct *tty)
1653{
1654 /*
1655 * Ask the line discipline code to release its structures
1656 */
1657 tty_ldisc_release(tty);
1658
1659 /* Wait for pending work before tty destruction commences */
1660 tty_flush_works(tty);
1661
1662 tty_debug_hangup(tty, "freeing structure\n");
1663 /*
1664 * The release_tty function takes care of the details of clearing
1665 * the slots and preserving the termios structure.
1666 */
1667 mutex_lock(&tty_mutex);
1668 tty_port_set_kopened(tty->port, 0);
1669 release_tty(tty, tty->index);
1670 mutex_unlock(&tty_mutex);
1671}
1672EXPORT_SYMBOL_GPL(tty_kclose);
1673
1674/**
1675 * tty_release_struct - release a tty struct
1676 * @tty: tty device
1677 * @idx: index of the tty
1678 *
1679 * Performs the final steps to release and free a tty device. It is roughly the
1680 * reverse of tty_init_dev().
1681 */
1682void tty_release_struct(struct tty_struct *tty, int idx)
1683{
1684 /*
1685 * Ask the line discipline code to release its structures
1686 */
1687 tty_ldisc_release(tty);
1688
1689 /* Wait for pending work before tty destruction commmences */
1690 tty_flush_works(tty);
1691
1692 tty_debug_hangup(tty, "freeing structure\n");
1693 /*
1694 * The release_tty function takes care of the details of clearing
1695 * the slots and preserving the termios structure.
1696 */
1697 mutex_lock(&tty_mutex);
1698 release_tty(tty, idx);
1699 mutex_unlock(&tty_mutex);
1700}
1701EXPORT_SYMBOL_GPL(tty_release_struct);
1702
1703/**
1704 * tty_release - vfs callback for close
1705 * @inode: inode of tty
1706 * @filp: file pointer for handle to tty
1707 *
1708 * Called the last time each file handle is closed that references this tty.
1709 * There may however be several such references.
1710 *
1711 * Locking:
1712 * Takes BKL. See tty_release_dev().
1713 *
1714 * Even releasing the tty structures is a tricky business. We have to be very
1715 * careful that the structures are all released at the same time, as interrupts
1716 * might otherwise get the wrong pointers.
1717 *
1718 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1719 * lead to double frees or releasing memory still in use.
1720 */
1721int tty_release(struct inode *inode, struct file *filp)
1722{
1723 struct tty_struct *tty = file_tty(filp);
1724 struct tty_struct *o_tty = NULL;
1725 int do_sleep, final;
1726 int idx;
1727 long timeout = 0;
1728 int once = 1;
1729
1730 if (tty_paranoia_check(tty, inode, __func__))
1731 return 0;
1732
1733 tty_lock(tty);
1734 check_tty_count(tty, __func__);
1735
1736 __tty_fasync(-1, filp, 0);
1737
1738 idx = tty->index;
1739 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1740 tty->driver->subtype == PTY_TYPE_MASTER)
1741 o_tty = tty->link;
1742
1743 if (tty_release_checks(tty, idx)) {
1744 tty_unlock(tty);
1745 return 0;
1746 }
1747
1748 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1749
1750 if (tty->ops->close)
1751 tty->ops->close(tty, filp);
1752
1753 /* If tty is pty master, lock the slave pty (stable lock order) */
1754 tty_lock_slave(o_tty);
1755
1756 /*
1757 * Sanity check: if tty->count is going to zero, there shouldn't be
1758 * any waiters on tty->read_wait or tty->write_wait. We test the
1759 * wait queues and kick everyone out _before_ actually starting to
1760 * close. This ensures that we won't block while releasing the tty
1761 * structure.
1762 *
1763 * The test for the o_tty closing is necessary, since the master and
1764 * slave sides may close in any order. If the slave side closes out
1765 * first, its count will be one, since the master side holds an open.
1766 * Thus this test wouldn't be triggered at the time the slave closed,
1767 * so we do it now.
1768 */
1769 while (1) {
1770 do_sleep = 0;
1771
1772 if (tty->count <= 1) {
1773 if (waitqueue_active(&tty->read_wait)) {
1774 wake_up_poll(&tty->read_wait, EPOLLIN);
1775 do_sleep++;
1776 }
1777 if (waitqueue_active(&tty->write_wait)) {
1778 wake_up_poll(&tty->write_wait, EPOLLOUT);
1779 do_sleep++;
1780 }
1781 }
1782 if (o_tty && o_tty->count <= 1) {
1783 if (waitqueue_active(&o_tty->read_wait)) {
1784 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1785 do_sleep++;
1786 }
1787 if (waitqueue_active(&o_tty->write_wait)) {
1788 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1789 do_sleep++;
1790 }
1791 }
1792 if (!do_sleep)
1793 break;
1794
1795 if (once) {
1796 once = 0;
1797 tty_warn(tty, "read/write wait queue active!\n");
1798 }
1799 schedule_timeout_killable(timeout);
1800 if (timeout < 120 * HZ)
1801 timeout = 2 * timeout + 1;
1802 else
1803 timeout = MAX_SCHEDULE_TIMEOUT;
1804 }
1805
1806 if (o_tty) {
1807 if (--o_tty->count < 0) {
1808 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1809 o_tty->count = 0;
1810 }
1811 }
1812 if (--tty->count < 0) {
1813 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1814 tty->count = 0;
1815 }
1816
1817 /*
1818 * We've decremented tty->count, so we need to remove this file
1819 * descriptor off the tty->tty_files list; this serves two
1820 * purposes:
1821 * - check_tty_count sees the correct number of file descriptors
1822 * associated with this tty.
1823 * - do_tty_hangup no longer sees this file descriptor as
1824 * something that needs to be handled for hangups.
1825 */
1826 tty_del_file(filp);
1827
1828 /*
1829 * Perform some housekeeping before deciding whether to return.
1830 *
1831 * If _either_ side is closing, make sure there aren't any
1832 * processes that still think tty or o_tty is their controlling
1833 * tty.
1834 */
1835 if (!tty->count) {
1836 read_lock(&tasklist_lock);
1837 session_clear_tty(tty->ctrl.session);
1838 if (o_tty)
1839 session_clear_tty(o_tty->ctrl.session);
1840 read_unlock(&tasklist_lock);
1841 }
1842
1843 /* check whether both sides are closing ... */
1844 final = !tty->count && !(o_tty && o_tty->count);
1845
1846 tty_unlock_slave(o_tty);
1847 tty_unlock(tty);
1848
1849 /* At this point, the tty->count == 0 should ensure a dead tty
1850 * cannot be re-opened by a racing opener.
1851 */
1852
1853 if (!final)
1854 return 0;
1855
1856 tty_debug_hangup(tty, "final close\n");
1857
1858 tty_release_struct(tty, idx);
1859 return 0;
1860}
1861
1862/**
1863 * tty_open_current_tty - get locked tty of current task
1864 * @device: device number
1865 * @filp: file pointer to tty
1866 * @return: locked tty of the current task iff @device is /dev/tty
1867 *
1868 * Performs a re-open of the current task's controlling tty.
1869 *
1870 * We cannot return driver and index like for the other nodes because devpts
1871 * will not work then. It expects inodes to be from devpts FS.
1872 */
1873static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1874{
1875 struct tty_struct *tty;
1876 int retval;
1877
1878 if (device != MKDEV(TTYAUX_MAJOR, 0))
1879 return NULL;
1880
1881 tty = get_current_tty();
1882 if (!tty)
1883 return ERR_PTR(-ENXIO);
1884
1885 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1886 /* noctty = 1; */
1887 tty_lock(tty);
1888 tty_kref_put(tty); /* safe to drop the kref now */
1889
1890 retval = tty_reopen(tty);
1891 if (retval < 0) {
1892 tty_unlock(tty);
1893 tty = ERR_PTR(retval);
1894 }
1895 return tty;
1896}
1897
1898/**
1899 * tty_lookup_driver - lookup a tty driver for a given device file
1900 * @device: device number
1901 * @filp: file pointer to tty
1902 * @index: index for the device in the @return driver
1903 *
1904 * If returned value is not erroneous, the caller is responsible to decrement
1905 * the refcount by tty_driver_kref_put().
1906 *
1907 * Locking: %tty_mutex protects get_tty_driver()
1908 *
1909 * Return: driver for this inode (with increased refcount)
1910 */
1911static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1912 int *index)
1913{
1914 struct tty_driver *driver = NULL;
1915
1916 switch (device) {
1917#ifdef CONFIG_VT
1918 case MKDEV(TTY_MAJOR, 0): {
1919 extern struct tty_driver *console_driver;
1920
1921 driver = tty_driver_kref_get(console_driver);
1922 *index = fg_console;
1923 break;
1924 }
1925#endif
1926 case MKDEV(TTYAUX_MAJOR, 1): {
1927 struct tty_driver *console_driver = console_device(index);
1928
1929 if (console_driver) {
1930 driver = tty_driver_kref_get(console_driver);
1931 if (driver && filp) {
1932 /* Don't let /dev/console block */
1933 filp->f_flags |= O_NONBLOCK;
1934 break;
1935 }
1936 }
1937 if (driver)
1938 tty_driver_kref_put(driver);
1939 return ERR_PTR(-ENODEV);
1940 }
1941 default:
1942 driver = get_tty_driver(device, index);
1943 if (!driver)
1944 return ERR_PTR(-ENODEV);
1945 break;
1946 }
1947 return driver;
1948}
1949
1950static struct tty_struct *tty_kopen(dev_t device, int shared)
1951{
1952 struct tty_struct *tty;
1953 struct tty_driver *driver;
1954 int index = -1;
1955
1956 mutex_lock(&tty_mutex);
1957 driver = tty_lookup_driver(device, NULL, &index);
1958 if (IS_ERR(driver)) {
1959 mutex_unlock(&tty_mutex);
1960 return ERR_CAST(driver);
1961 }
1962
1963 /* check whether we're reopening an existing tty */
1964 tty = tty_driver_lookup_tty(driver, NULL, index);
1965 if (IS_ERR(tty) || shared)
1966 goto out;
1967
1968 if (tty) {
1969 /* drop kref from tty_driver_lookup_tty() */
1970 tty_kref_put(tty);
1971 tty = ERR_PTR(-EBUSY);
1972 } else { /* tty_init_dev returns tty with the tty_lock held */
1973 tty = tty_init_dev(driver, index);
1974 if (IS_ERR(tty))
1975 goto out;
1976 tty_port_set_kopened(tty->port, 1);
1977 }
1978out:
1979 mutex_unlock(&tty_mutex);
1980 tty_driver_kref_put(driver);
1981 return tty;
1982}
1983
1984/**
1985 * tty_kopen_exclusive - open a tty device for kernel
1986 * @device: dev_t of device to open
1987 *
1988 * Opens tty exclusively for kernel. Performs the driver lookup, makes sure
1989 * it's not already opened and performs the first-time tty initialization.
1990 *
1991 * Claims the global %tty_mutex to serialize:
1992 * * concurrent first-time tty initialization
1993 * * concurrent tty driver removal w/ lookup
1994 * * concurrent tty removal from driver table
1995 *
1996 * Return: the locked initialized &tty_struct
1997 */
1998struct tty_struct *tty_kopen_exclusive(dev_t device)
1999{
2000 return tty_kopen(device, 0);
2001}
2002EXPORT_SYMBOL_GPL(tty_kopen_exclusive);
2003
2004/**
2005 * tty_kopen_shared - open a tty device for shared in-kernel use
2006 * @device: dev_t of device to open
2007 *
2008 * Opens an already existing tty for in-kernel use. Compared to
2009 * tty_kopen_exclusive() above it doesn't ensure to be the only user.
2010 *
2011 * Locking: identical to tty_kopen() above.
2012 */
2013struct tty_struct *tty_kopen_shared(dev_t device)
2014{
2015 return tty_kopen(device, 1);
2016}
2017EXPORT_SYMBOL_GPL(tty_kopen_shared);
2018
2019/**
2020 * tty_open_by_driver - open a tty device
2021 * @device: dev_t of device to open
2022 * @filp: file pointer to tty
2023 *
2024 * Performs the driver lookup, checks for a reopen, or otherwise performs the
2025 * first-time tty initialization.
2026 *
2027 *
2028 * Claims the global tty_mutex to serialize:
2029 * * concurrent first-time tty initialization
2030 * * concurrent tty driver removal w/ lookup
2031 * * concurrent tty removal from driver table
2032 *
2033 * Return: the locked initialized or re-opened &tty_struct
2034 */
2035static struct tty_struct *tty_open_by_driver(dev_t device,
2036 struct file *filp)
2037{
2038 struct tty_struct *tty;
2039 struct tty_driver *driver = NULL;
2040 int index = -1;
2041 int retval;
2042
2043 mutex_lock(&tty_mutex);
2044 driver = tty_lookup_driver(device, filp, &index);
2045 if (IS_ERR(driver)) {
2046 mutex_unlock(&tty_mutex);
2047 return ERR_CAST(driver);
2048 }
2049
2050 /* check whether we're reopening an existing tty */
2051 tty = tty_driver_lookup_tty(driver, filp, index);
2052 if (IS_ERR(tty)) {
2053 mutex_unlock(&tty_mutex);
2054 goto out;
2055 }
2056
2057 if (tty) {
2058 if (tty_port_kopened(tty->port)) {
2059 tty_kref_put(tty);
2060 mutex_unlock(&tty_mutex);
2061 tty = ERR_PTR(-EBUSY);
2062 goto out;
2063 }
2064 mutex_unlock(&tty_mutex);
2065 retval = tty_lock_interruptible(tty);
2066 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2067 if (retval) {
2068 if (retval == -EINTR)
2069 retval = -ERESTARTSYS;
2070 tty = ERR_PTR(retval);
2071 goto out;
2072 }
2073 retval = tty_reopen(tty);
2074 if (retval < 0) {
2075 tty_unlock(tty);
2076 tty = ERR_PTR(retval);
2077 }
2078 } else { /* Returns with the tty_lock held for now */
2079 tty = tty_init_dev(driver, index);
2080 mutex_unlock(&tty_mutex);
2081 }
2082out:
2083 tty_driver_kref_put(driver);
2084 return tty;
2085}
2086
2087/**
2088 * tty_open - open a tty device
2089 * @inode: inode of device file
2090 * @filp: file pointer to tty
2091 *
2092 * tty_open() and tty_release() keep up the tty count that contains the number
2093 * of opens done on a tty. We cannot use the inode-count, as different inodes
2094 * might point to the same tty.
2095 *
2096 * Open-counting is needed for pty masters, as well as for keeping track of
2097 * serial lines: DTR is dropped when the last close happens.
2098 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2099 *
2100 * The termios state of a pty is reset on the first open so that settings don't
2101 * persist across reuse.
2102 *
2103 * Locking:
2104 * * %tty_mutex protects tty, tty_lookup_driver() and tty_init_dev().
2105 * * @tty->count should protect the rest.
2106 * * ->siglock protects ->signal/->sighand
2107 *
2108 * Note: the tty_unlock/lock cases without a ref are only safe due to %tty_mutex
2109 */
2110static int tty_open(struct inode *inode, struct file *filp)
2111{
2112 struct tty_struct *tty;
2113 int noctty, retval;
2114 dev_t device = inode->i_rdev;
2115 unsigned saved_flags = filp->f_flags;
2116
2117 nonseekable_open(inode, filp);
2118
2119retry_open:
2120 retval = tty_alloc_file(filp);
2121 if (retval)
2122 return -ENOMEM;
2123
2124 tty = tty_open_current_tty(device, filp);
2125 if (!tty)
2126 tty = tty_open_by_driver(device, filp);
2127
2128 if (IS_ERR(tty)) {
2129 tty_free_file(filp);
2130 retval = PTR_ERR(tty);
2131 if (retval != -EAGAIN || signal_pending(current))
2132 return retval;
2133 schedule();
2134 goto retry_open;
2135 }
2136
2137 tty_add_file(tty, filp);
2138
2139 check_tty_count(tty, __func__);
2140 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2141
2142 if (tty->ops->open)
2143 retval = tty->ops->open(tty, filp);
2144 else
2145 retval = -ENODEV;
2146 filp->f_flags = saved_flags;
2147
2148 if (retval) {
2149 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2150
2151 tty_unlock(tty); /* need to call tty_release without BTM */
2152 tty_release(inode, filp);
2153 if (retval != -ERESTARTSYS)
2154 return retval;
2155
2156 if (signal_pending(current))
2157 return retval;
2158
2159 schedule();
2160 /*
2161 * Need to reset f_op in case a hangup happened.
2162 */
2163 if (tty_hung_up_p(filp))
2164 filp->f_op = &tty_fops;
2165 goto retry_open;
2166 }
2167 clear_bit(TTY_HUPPED, &tty->flags);
2168
2169 noctty = (filp->f_flags & O_NOCTTY) ||
2170 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2171 device == MKDEV(TTYAUX_MAJOR, 1) ||
2172 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2173 tty->driver->subtype == PTY_TYPE_MASTER);
2174 if (!noctty)
2175 tty_open_proc_set_tty(filp, tty);
2176 tty_unlock(tty);
2177 return 0;
2178}
2179
2180
2181/**
2182 * tty_poll - check tty status
2183 * @filp: file being polled
2184 * @wait: poll wait structures to update
2185 *
2186 * Call the line discipline polling method to obtain the poll status of the
2187 * device.
2188 *
2189 * Locking: locks called line discipline but ldisc poll method may be
2190 * re-entered freely by other callers.
2191 */
2192static __poll_t tty_poll(struct file *filp, poll_table *wait)
2193{
2194 struct tty_struct *tty = file_tty(filp);
2195 struct tty_ldisc *ld;
2196 __poll_t ret = 0;
2197
2198 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2199 return 0;
2200
2201 ld = tty_ldisc_ref_wait(tty);
2202 if (!ld)
2203 return hung_up_tty_poll(filp, wait);
2204 if (ld->ops->poll)
2205 ret = ld->ops->poll(tty, filp, wait);
2206 tty_ldisc_deref(ld);
2207 return ret;
2208}
2209
2210static int __tty_fasync(int fd, struct file *filp, int on)
2211{
2212 struct tty_struct *tty = file_tty(filp);
2213 unsigned long flags;
2214 int retval = 0;
2215
2216 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2217 goto out;
2218
2219 retval = fasync_helper(fd, filp, on, &tty->fasync);
2220 if (retval <= 0)
2221 goto out;
2222
2223 if (on) {
2224 enum pid_type type;
2225 struct pid *pid;
2226
2227 spin_lock_irqsave(&tty->ctrl.lock, flags);
2228 if (tty->ctrl.pgrp) {
2229 pid = tty->ctrl.pgrp;
2230 type = PIDTYPE_PGID;
2231 } else {
2232 pid = task_pid(current);
2233 type = PIDTYPE_TGID;
2234 }
2235 get_pid(pid);
2236 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
2237 __f_setown(filp, pid, type, 0);
2238 put_pid(pid);
2239 retval = 0;
2240 }
2241out:
2242 return retval;
2243}
2244
2245static int tty_fasync(int fd, struct file *filp, int on)
2246{
2247 struct tty_struct *tty = file_tty(filp);
2248 int retval = -ENOTTY;
2249
2250 tty_lock(tty);
2251 if (!tty_hung_up_p(filp))
2252 retval = __tty_fasync(fd, filp, on);
2253 tty_unlock(tty);
2254
2255 return retval;
2256}
2257
2258static bool tty_legacy_tiocsti __read_mostly = IS_ENABLED(CONFIG_LEGACY_TIOCSTI);
2259/**
2260 * tiocsti - fake input character
2261 * @tty: tty to fake input into
2262 * @p: pointer to character
2263 *
2264 * Fake input to a tty device. Does the necessary locking and input management.
2265 *
2266 * FIXME: does not honour flow control ??
2267 *
2268 * Locking:
2269 * * Called functions take tty_ldiscs_lock
2270 * * current->signal->tty check is safe without locks
2271 */
2272static int tiocsti(struct tty_struct *tty, char __user *p)
2273{
2274 char ch, mbz = 0;
2275 struct tty_ldisc *ld;
2276
2277 if (!tty_legacy_tiocsti)
2278 return -EIO;
2279
2280 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2281 return -EPERM;
2282 if (get_user(ch, p))
2283 return -EFAULT;
2284 tty_audit_tiocsti(tty, ch);
2285 ld = tty_ldisc_ref_wait(tty);
2286 if (!ld)
2287 return -EIO;
2288 tty_buffer_lock_exclusive(tty->port);
2289 if (ld->ops->receive_buf)
2290 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2291 tty_buffer_unlock_exclusive(tty->port);
2292 tty_ldisc_deref(ld);
2293 return 0;
2294}
2295
2296/**
2297 * tiocgwinsz - implement window query ioctl
2298 * @tty: tty
2299 * @arg: user buffer for result
2300 *
2301 * Copies the kernel idea of the window size into the user buffer.
2302 *
2303 * Locking: @tty->winsize_mutex is taken to ensure the winsize data is
2304 * consistent.
2305 */
2306static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2307{
2308 int err;
2309
2310 mutex_lock(&tty->winsize_mutex);
2311 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2312 mutex_unlock(&tty->winsize_mutex);
2313
2314 return err ? -EFAULT : 0;
2315}
2316
2317/**
2318 * tty_do_resize - resize event
2319 * @tty: tty being resized
2320 * @ws: new dimensions
2321 *
2322 * Update the termios variables and send the necessary signals to peform a
2323 * terminal resize correctly.
2324 */
2325int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2326{
2327 struct pid *pgrp;
2328
2329 /* Lock the tty */
2330 mutex_lock(&tty->winsize_mutex);
2331 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2332 goto done;
2333
2334 /* Signal the foreground process group */
2335 pgrp = tty_get_pgrp(tty);
2336 if (pgrp)
2337 kill_pgrp(pgrp, SIGWINCH, 1);
2338 put_pid(pgrp);
2339
2340 tty->winsize = *ws;
2341done:
2342 mutex_unlock(&tty->winsize_mutex);
2343 return 0;
2344}
2345EXPORT_SYMBOL(tty_do_resize);
2346
2347/**
2348 * tiocswinsz - implement window size set ioctl
2349 * @tty: tty side of tty
2350 * @arg: user buffer for result
2351 *
2352 * Copies the user idea of the window size to the kernel. Traditionally this is
2353 * just advisory information but for the Linux console it actually has driver
2354 * level meaning and triggers a VC resize.
2355 *
2356 * Locking:
2357 * Driver dependent. The default do_resize method takes the tty termios
2358 * mutex and ctrl.lock. The console takes its own lock then calls into the
2359 * default method.
2360 */
2361static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2362{
2363 struct winsize tmp_ws;
2364
2365 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2366 return -EFAULT;
2367
2368 if (tty->ops->resize)
2369 return tty->ops->resize(tty, &tmp_ws);
2370 else
2371 return tty_do_resize(tty, &tmp_ws);
2372}
2373
2374/**
2375 * tioccons - allow admin to move logical console
2376 * @file: the file to become console
2377 *
2378 * Allow the administrator to move the redirected console device.
2379 *
2380 * Locking: uses redirect_lock to guard the redirect information
2381 */
2382static int tioccons(struct file *file)
2383{
2384 if (!capable(CAP_SYS_ADMIN))
2385 return -EPERM;
2386 if (file->f_op->write_iter == redirected_tty_write) {
2387 struct file *f;
2388
2389 spin_lock(&redirect_lock);
2390 f = redirect;
2391 redirect = NULL;
2392 spin_unlock(&redirect_lock);
2393 if (f)
2394 fput(f);
2395 return 0;
2396 }
2397 if (file->f_op->write_iter != tty_write)
2398 return -ENOTTY;
2399 if (!(file->f_mode & FMODE_WRITE))
2400 return -EBADF;
2401 if (!(file->f_mode & FMODE_CAN_WRITE))
2402 return -EINVAL;
2403 spin_lock(&redirect_lock);
2404 if (redirect) {
2405 spin_unlock(&redirect_lock);
2406 return -EBUSY;
2407 }
2408 redirect = get_file(file);
2409 spin_unlock(&redirect_lock);
2410 return 0;
2411}
2412
2413/**
2414 * tiocsetd - set line discipline
2415 * @tty: tty device
2416 * @p: pointer to user data
2417 *
2418 * Set the line discipline according to user request.
2419 *
2420 * Locking: see tty_set_ldisc(), this function is just a helper
2421 */
2422static int tiocsetd(struct tty_struct *tty, int __user *p)
2423{
2424 int disc;
2425 int ret;
2426
2427 if (get_user(disc, p))
2428 return -EFAULT;
2429
2430 ret = tty_set_ldisc(tty, disc);
2431
2432 return ret;
2433}
2434
2435/**
2436 * tiocgetd - get line discipline
2437 * @tty: tty device
2438 * @p: pointer to user data
2439 *
2440 * Retrieves the line discipline id directly from the ldisc.
2441 *
2442 * Locking: waits for ldisc reference (in case the line discipline is changing
2443 * or the @tty is being hungup)
2444 */
2445static int tiocgetd(struct tty_struct *tty, int __user *p)
2446{
2447 struct tty_ldisc *ld;
2448 int ret;
2449
2450 ld = tty_ldisc_ref_wait(tty);
2451 if (!ld)
2452 return -EIO;
2453 ret = put_user(ld->ops->num, p);
2454 tty_ldisc_deref(ld);
2455 return ret;
2456}
2457
2458/**
2459 * send_break - performed time break
2460 * @tty: device to break on
2461 * @duration: timeout in mS
2462 *
2463 * Perform a timed break on hardware that lacks its own driver level timed
2464 * break functionality.
2465 *
2466 * Locking:
2467 * @tty->atomic_write_lock serializes
2468 */
2469static int send_break(struct tty_struct *tty, unsigned int duration)
2470{
2471 int retval;
2472
2473 if (tty->ops->break_ctl == NULL)
2474 return 0;
2475
2476 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2477 retval = tty->ops->break_ctl(tty, duration);
2478 else {
2479 /* Do the work ourselves */
2480 if (tty_write_lock(tty, 0) < 0)
2481 return -EINTR;
2482 retval = tty->ops->break_ctl(tty, -1);
2483 if (retval)
2484 goto out;
2485 if (!signal_pending(current))
2486 msleep_interruptible(duration);
2487 retval = tty->ops->break_ctl(tty, 0);
2488out:
2489 tty_write_unlock(tty);
2490 if (signal_pending(current))
2491 retval = -EINTR;
2492 }
2493 return retval;
2494}
2495
2496/**
2497 * tty_tiocmget - get modem status
2498 * @tty: tty device
2499 * @p: pointer to result
2500 *
2501 * Obtain the modem status bits from the tty driver if the feature is
2502 * supported. Return -%ENOTTY if it is not available.
2503 *
2504 * Locking: none (up to the driver)
2505 */
2506static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2507{
2508 int retval = -ENOTTY;
2509
2510 if (tty->ops->tiocmget) {
2511 retval = tty->ops->tiocmget(tty);
2512
2513 if (retval >= 0)
2514 retval = put_user(retval, p);
2515 }
2516 return retval;
2517}
2518
2519/**
2520 * tty_tiocmset - set modem status
2521 * @tty: tty device
2522 * @cmd: command - clear bits, set bits or set all
2523 * @p: pointer to desired bits
2524 *
2525 * Set the modem status bits from the tty driver if the feature
2526 * is supported. Return -%ENOTTY if it is not available.
2527 *
2528 * Locking: none (up to the driver)
2529 */
2530static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2531 unsigned __user *p)
2532{
2533 int retval;
2534 unsigned int set, clear, val;
2535
2536 if (tty->ops->tiocmset == NULL)
2537 return -ENOTTY;
2538
2539 retval = get_user(val, p);
2540 if (retval)
2541 return retval;
2542 set = clear = 0;
2543 switch (cmd) {
2544 case TIOCMBIS:
2545 set = val;
2546 break;
2547 case TIOCMBIC:
2548 clear = val;
2549 break;
2550 case TIOCMSET:
2551 set = val;
2552 clear = ~val;
2553 break;
2554 }
2555 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2556 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2557 return tty->ops->tiocmset(tty, set, clear);
2558}
2559
2560/**
2561 * tty_get_icount - get tty statistics
2562 * @tty: tty device
2563 * @icount: output parameter
2564 *
2565 * Gets a copy of the @tty's icount statistics.
2566 *
2567 * Locking: none (up to the driver)
2568 */
2569int tty_get_icount(struct tty_struct *tty,
2570 struct serial_icounter_struct *icount)
2571{
2572 memset(icount, 0, sizeof(*icount));
2573
2574 if (tty->ops->get_icount)
2575 return tty->ops->get_icount(tty, icount);
2576 else
2577 return -ENOTTY;
2578}
2579EXPORT_SYMBOL_GPL(tty_get_icount);
2580
2581static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2582{
2583 struct serial_icounter_struct icount;
2584 int retval;
2585
2586 retval = tty_get_icount(tty, &icount);
2587 if (retval != 0)
2588 return retval;
2589
2590 if (copy_to_user(arg, &icount, sizeof(icount)))
2591 return -EFAULT;
2592 return 0;
2593}
2594
2595static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss)
2596{
2597 char comm[TASK_COMM_LEN];
2598 int flags;
2599
2600 flags = ss->flags & ASYNC_DEPRECATED;
2601
2602 if (flags)
2603 pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2604 __func__, get_task_comm(comm, current), flags);
2605
2606 if (!tty->ops->set_serial)
2607 return -ENOTTY;
2608
2609 return tty->ops->set_serial(tty, ss);
2610}
2611
2612static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2613{
2614 struct serial_struct v;
2615
2616 if (copy_from_user(&v, ss, sizeof(*ss)))
2617 return -EFAULT;
2618
2619 return tty_set_serial(tty, &v);
2620}
2621
2622static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2623{
2624 struct serial_struct v;
2625 int err;
2626
2627 memset(&v, 0, sizeof(v));
2628 if (!tty->ops->get_serial)
2629 return -ENOTTY;
2630 err = tty->ops->get_serial(tty, &v);
2631 if (!err && copy_to_user(ss, &v, sizeof(v)))
2632 err = -EFAULT;
2633 return err;
2634}
2635
2636/*
2637 * if pty, return the slave side (real_tty)
2638 * otherwise, return self
2639 */
2640static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2641{
2642 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2643 tty->driver->subtype == PTY_TYPE_MASTER)
2644 tty = tty->link;
2645 return tty;
2646}
2647
2648/*
2649 * Split this up, as gcc can choke on it otherwise..
2650 */
2651long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2652{
2653 struct tty_struct *tty = file_tty(file);
2654 struct tty_struct *real_tty;
2655 void __user *p = (void __user *)arg;
2656 int retval;
2657 struct tty_ldisc *ld;
2658
2659 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2660 return -EINVAL;
2661
2662 real_tty = tty_pair_get_tty(tty);
2663
2664 /*
2665 * Factor out some common prep work
2666 */
2667 switch (cmd) {
2668 case TIOCSETD:
2669 case TIOCSBRK:
2670 case TIOCCBRK:
2671 case TCSBRK:
2672 case TCSBRKP:
2673 retval = tty_check_change(tty);
2674 if (retval)
2675 return retval;
2676 if (cmd != TIOCCBRK) {
2677 tty_wait_until_sent(tty, 0);
2678 if (signal_pending(current))
2679 return -EINTR;
2680 }
2681 break;
2682 }
2683
2684 /*
2685 * Now do the stuff.
2686 */
2687 switch (cmd) {
2688 case TIOCSTI:
2689 return tiocsti(tty, p);
2690 case TIOCGWINSZ:
2691 return tiocgwinsz(real_tty, p);
2692 case TIOCSWINSZ:
2693 return tiocswinsz(real_tty, p);
2694 case TIOCCONS:
2695 return real_tty != tty ? -EINVAL : tioccons(file);
2696 case TIOCEXCL:
2697 set_bit(TTY_EXCLUSIVE, &tty->flags);
2698 return 0;
2699 case TIOCNXCL:
2700 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2701 return 0;
2702 case TIOCGEXCL:
2703 {
2704 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2705
2706 return put_user(excl, (int __user *)p);
2707 }
2708 case TIOCGETD:
2709 return tiocgetd(tty, p);
2710 case TIOCSETD:
2711 return tiocsetd(tty, p);
2712 case TIOCVHANGUP:
2713 if (!capable(CAP_SYS_ADMIN))
2714 return -EPERM;
2715 tty_vhangup(tty);
2716 return 0;
2717 case TIOCGDEV:
2718 {
2719 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2720
2721 return put_user(ret, (unsigned int __user *)p);
2722 }
2723 /*
2724 * Break handling
2725 */
2726 case TIOCSBRK: /* Turn break on, unconditionally */
2727 if (tty->ops->break_ctl)
2728 return tty->ops->break_ctl(tty, -1);
2729 return 0;
2730 case TIOCCBRK: /* Turn break off, unconditionally */
2731 if (tty->ops->break_ctl)
2732 return tty->ops->break_ctl(tty, 0);
2733 return 0;
2734 case TCSBRK: /* SVID version: non-zero arg --> no break */
2735 /* non-zero arg means wait for all output data
2736 * to be sent (performed above) but don't send break.
2737 * This is used by the tcdrain() termios function.
2738 */
2739 if (!arg)
2740 return send_break(tty, 250);
2741 return 0;
2742 case TCSBRKP: /* support for POSIX tcsendbreak() */
2743 return send_break(tty, arg ? arg*100 : 250);
2744
2745 case TIOCMGET:
2746 return tty_tiocmget(tty, p);
2747 case TIOCMSET:
2748 case TIOCMBIC:
2749 case TIOCMBIS:
2750 return tty_tiocmset(tty, cmd, p);
2751 case TIOCGICOUNT:
2752 return tty_tiocgicount(tty, p);
2753 case TCFLSH:
2754 switch (arg) {
2755 case TCIFLUSH:
2756 case TCIOFLUSH:
2757 /* flush tty buffer and allow ldisc to process ioctl */
2758 tty_buffer_flush(tty, NULL);
2759 break;
2760 }
2761 break;
2762 case TIOCSSERIAL:
2763 return tty_tiocsserial(tty, p);
2764 case TIOCGSERIAL:
2765 return tty_tiocgserial(tty, p);
2766 case TIOCGPTPEER:
2767 /* Special because the struct file is needed */
2768 return ptm_open_peer(file, tty, (int)arg);
2769 default:
2770 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2771 if (retval != -ENOIOCTLCMD)
2772 return retval;
2773 }
2774 if (tty->ops->ioctl) {
2775 retval = tty->ops->ioctl(tty, cmd, arg);
2776 if (retval != -ENOIOCTLCMD)
2777 return retval;
2778 }
2779 ld = tty_ldisc_ref_wait(tty);
2780 if (!ld)
2781 return hung_up_tty_ioctl(file, cmd, arg);
2782 retval = -EINVAL;
2783 if (ld->ops->ioctl) {
2784 retval = ld->ops->ioctl(tty, cmd, arg);
2785 if (retval == -ENOIOCTLCMD)
2786 retval = -ENOTTY;
2787 }
2788 tty_ldisc_deref(ld);
2789 return retval;
2790}
2791
2792#ifdef CONFIG_COMPAT
2793
2794struct serial_struct32 {
2795 compat_int_t type;
2796 compat_int_t line;
2797 compat_uint_t port;
2798 compat_int_t irq;
2799 compat_int_t flags;
2800 compat_int_t xmit_fifo_size;
2801 compat_int_t custom_divisor;
2802 compat_int_t baud_base;
2803 unsigned short close_delay;
2804 char io_type;
2805 char reserved_char;
2806 compat_int_t hub6;
2807 unsigned short closing_wait; /* time to wait before closing */
2808 unsigned short closing_wait2; /* no longer used... */
2809 compat_uint_t iomem_base;
2810 unsigned short iomem_reg_shift;
2811 unsigned int port_high;
2812 /* compat_ulong_t iomap_base FIXME */
2813 compat_int_t reserved;
2814};
2815
2816static int compat_tty_tiocsserial(struct tty_struct *tty,
2817 struct serial_struct32 __user *ss)
2818{
2819 struct serial_struct32 v32;
2820 struct serial_struct v;
2821
2822 if (copy_from_user(&v32, ss, sizeof(*ss)))
2823 return -EFAULT;
2824
2825 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2826 v.iomem_base = compat_ptr(v32.iomem_base);
2827 v.iomem_reg_shift = v32.iomem_reg_shift;
2828 v.port_high = v32.port_high;
2829 v.iomap_base = 0;
2830
2831 return tty_set_serial(tty, &v);
2832}
2833
2834static int compat_tty_tiocgserial(struct tty_struct *tty,
2835 struct serial_struct32 __user *ss)
2836{
2837 struct serial_struct32 v32;
2838 struct serial_struct v;
2839 int err;
2840
2841 memset(&v, 0, sizeof(v));
2842 memset(&v32, 0, sizeof(v32));
2843
2844 if (!tty->ops->get_serial)
2845 return -ENOTTY;
2846 err = tty->ops->get_serial(tty, &v);
2847 if (!err) {
2848 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2849 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2850 0xfffffff : ptr_to_compat(v.iomem_base);
2851 v32.iomem_reg_shift = v.iomem_reg_shift;
2852 v32.port_high = v.port_high;
2853 if (copy_to_user(ss, &v32, sizeof(v32)))
2854 err = -EFAULT;
2855 }
2856 return err;
2857}
2858static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2859 unsigned long arg)
2860{
2861 struct tty_struct *tty = file_tty(file);
2862 struct tty_ldisc *ld;
2863 int retval = -ENOIOCTLCMD;
2864
2865 switch (cmd) {
2866 case TIOCOUTQ:
2867 case TIOCSTI:
2868 case TIOCGWINSZ:
2869 case TIOCSWINSZ:
2870 case TIOCGEXCL:
2871 case TIOCGETD:
2872 case TIOCSETD:
2873 case TIOCGDEV:
2874 case TIOCMGET:
2875 case TIOCMSET:
2876 case TIOCMBIC:
2877 case TIOCMBIS:
2878 case TIOCGICOUNT:
2879 case TIOCGPGRP:
2880 case TIOCSPGRP:
2881 case TIOCGSID:
2882 case TIOCSERGETLSR:
2883 case TIOCGRS485:
2884 case TIOCSRS485:
2885#ifdef TIOCGETP
2886 case TIOCGETP:
2887 case TIOCSETP:
2888 case TIOCSETN:
2889#endif
2890#ifdef TIOCGETC
2891 case TIOCGETC:
2892 case TIOCSETC:
2893#endif
2894#ifdef TIOCGLTC
2895 case TIOCGLTC:
2896 case TIOCSLTC:
2897#endif
2898 case TCSETSF:
2899 case TCSETSW:
2900 case TCSETS:
2901 case TCGETS:
2902#ifdef TCGETS2
2903 case TCGETS2:
2904 case TCSETSF2:
2905 case TCSETSW2:
2906 case TCSETS2:
2907#endif
2908 case TCGETA:
2909 case TCSETAF:
2910 case TCSETAW:
2911 case TCSETA:
2912 case TIOCGLCKTRMIOS:
2913 case TIOCSLCKTRMIOS:
2914#ifdef TCGETX
2915 case TCGETX:
2916 case TCSETX:
2917 case TCSETXW:
2918 case TCSETXF:
2919#endif
2920 case TIOCGSOFTCAR:
2921 case TIOCSSOFTCAR:
2922
2923 case PPPIOCGCHAN:
2924 case PPPIOCGUNIT:
2925 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2926 case TIOCCONS:
2927 case TIOCEXCL:
2928 case TIOCNXCL:
2929 case TIOCVHANGUP:
2930 case TIOCSBRK:
2931 case TIOCCBRK:
2932 case TCSBRK:
2933 case TCSBRKP:
2934 case TCFLSH:
2935 case TIOCGPTPEER:
2936 case TIOCNOTTY:
2937 case TIOCSCTTY:
2938 case TCXONC:
2939 case TIOCMIWAIT:
2940 case TIOCSERCONFIG:
2941 return tty_ioctl(file, cmd, arg);
2942 }
2943
2944 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2945 return -EINVAL;
2946
2947 switch (cmd) {
2948 case TIOCSSERIAL:
2949 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2950 case TIOCGSERIAL:
2951 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2952 }
2953 if (tty->ops->compat_ioctl) {
2954 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2955 if (retval != -ENOIOCTLCMD)
2956 return retval;
2957 }
2958
2959 ld = tty_ldisc_ref_wait(tty);
2960 if (!ld)
2961 return hung_up_tty_compat_ioctl(file, cmd, arg);
2962 if (ld->ops->compat_ioctl)
2963 retval = ld->ops->compat_ioctl(tty, cmd, arg);
2964 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2965 retval = ld->ops->ioctl(tty, (unsigned long)compat_ptr(cmd),
2966 arg);
2967 tty_ldisc_deref(ld);
2968
2969 return retval;
2970}
2971#endif
2972
2973static int this_tty(const void *t, struct file *file, unsigned fd)
2974{
2975 if (likely(file->f_op->read_iter != tty_read))
2976 return 0;
2977 return file_tty(file) != t ? 0 : fd + 1;
2978}
2979
2980/*
2981 * This implements the "Secure Attention Key" --- the idea is to
2982 * prevent trojan horses by killing all processes associated with this
2983 * tty when the user hits the "Secure Attention Key". Required for
2984 * super-paranoid applications --- see the Orange Book for more details.
2985 *
2986 * This code could be nicer; ideally it should send a HUP, wait a few
2987 * seconds, then send a INT, and then a KILL signal. But you then
2988 * have to coordinate with the init process, since all processes associated
2989 * with the current tty must be dead before the new getty is allowed
2990 * to spawn.
2991 *
2992 * Now, if it would be correct ;-/ The current code has a nasty hole -
2993 * it doesn't catch files in flight. We may send the descriptor to ourselves
2994 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2995 *
2996 * Nasty bug: do_SAK is being called in interrupt context. This can
2997 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2998 */
2999void __do_SAK(struct tty_struct *tty)
3000{
3001 struct task_struct *g, *p;
3002 struct pid *session;
3003 int i;
3004 unsigned long flags;
3005
3006 spin_lock_irqsave(&tty->ctrl.lock, flags);
3007 session = get_pid(tty->ctrl.session);
3008 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
3009
3010 tty_ldisc_flush(tty);
3011
3012 tty_driver_flush_buffer(tty);
3013
3014 read_lock(&tasklist_lock);
3015 /* Kill the entire session */
3016 do_each_pid_task(session, PIDTYPE_SID, p) {
3017 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3018 task_pid_nr(p), p->comm);
3019 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3020 } while_each_pid_task(session, PIDTYPE_SID, p);
3021
3022 /* Now kill any processes that happen to have the tty open */
3023 do_each_thread(g, p) {
3024 if (p->signal->tty == tty) {
3025 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3026 task_pid_nr(p), p->comm);
3027 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
3028 PIDTYPE_SID);
3029 continue;
3030 }
3031 task_lock(p);
3032 i = iterate_fd(p->files, 0, this_tty, tty);
3033 if (i != 0) {
3034 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3035 task_pid_nr(p), p->comm, i - 1);
3036 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
3037 PIDTYPE_SID);
3038 }
3039 task_unlock(p);
3040 } while_each_thread(g, p);
3041 read_unlock(&tasklist_lock);
3042 put_pid(session);
3043}
3044
3045static void do_SAK_work(struct work_struct *work)
3046{
3047 struct tty_struct *tty =
3048 container_of(work, struct tty_struct, SAK_work);
3049 __do_SAK(tty);
3050}
3051
3052/*
3053 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3054 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3055 * the values which we write to it will be identical to the values which it
3056 * already has. --akpm
3057 */
3058void do_SAK(struct tty_struct *tty)
3059{
3060 if (!tty)
3061 return;
3062 schedule_work(&tty->SAK_work);
3063}
3064EXPORT_SYMBOL(do_SAK);
3065
3066/* Must put_device() after it's unused! */
3067static struct device *tty_get_device(struct tty_struct *tty)
3068{
3069 dev_t devt = tty_devnum(tty);
3070
3071 return class_find_device_by_devt(tty_class, devt);
3072}
3073
3074
3075/**
3076 * alloc_tty_struct - allocate a new tty
3077 * @driver: driver which will handle the returned tty
3078 * @idx: minor of the tty
3079 *
3080 * This subroutine allocates and initializes a tty structure.
3081 *
3082 * Locking: none - @tty in question is not exposed at this point
3083 */
3084struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3085{
3086 struct tty_struct *tty;
3087
3088 tty = kzalloc(sizeof(*tty), GFP_KERNEL_ACCOUNT);
3089 if (!tty)
3090 return NULL;
3091
3092 kref_init(&tty->kref);
3093 if (tty_ldisc_init(tty)) {
3094 kfree(tty);
3095 return NULL;
3096 }
3097 tty->ctrl.session = NULL;
3098 tty->ctrl.pgrp = NULL;
3099 mutex_init(&tty->legacy_mutex);
3100 mutex_init(&tty->throttle_mutex);
3101 init_rwsem(&tty->termios_rwsem);
3102 mutex_init(&tty->winsize_mutex);
3103 init_ldsem(&tty->ldisc_sem);
3104 init_waitqueue_head(&tty->write_wait);
3105 init_waitqueue_head(&tty->read_wait);
3106 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3107 mutex_init(&tty->atomic_write_lock);
3108 spin_lock_init(&tty->ctrl.lock);
3109 spin_lock_init(&tty->flow.lock);
3110 spin_lock_init(&tty->files_lock);
3111 INIT_LIST_HEAD(&tty->tty_files);
3112 INIT_WORK(&tty->SAK_work, do_SAK_work);
3113
3114 tty->driver = driver;
3115 tty->ops = driver->ops;
3116 tty->index = idx;
3117 tty_line_name(driver, idx, tty->name);
3118 tty->dev = tty_get_device(tty);
3119
3120 return tty;
3121}
3122
3123/**
3124 * tty_put_char - write one character to a tty
3125 * @tty: tty
3126 * @ch: character to write
3127 *
3128 * Write one byte to the @tty using the provided @tty->ops->put_char() method
3129 * if present.
3130 *
3131 * Note: the specific put_char operation in the driver layer may go
3132 * away soon. Don't call it directly, use this method
3133 *
3134 * Return: the number of characters successfully output.
3135 */
3136int tty_put_char(struct tty_struct *tty, unsigned char ch)
3137{
3138 if (tty->ops->put_char)
3139 return tty->ops->put_char(tty, ch);
3140 return tty->ops->write(tty, &ch, 1);
3141}
3142EXPORT_SYMBOL_GPL(tty_put_char);
3143
3144struct class *tty_class;
3145
3146static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3147 unsigned int index, unsigned int count)
3148{
3149 int err;
3150
3151 /* init here, since reused cdevs cause crashes */
3152 driver->cdevs[index] = cdev_alloc();
3153 if (!driver->cdevs[index])
3154 return -ENOMEM;
3155 driver->cdevs[index]->ops = &tty_fops;
3156 driver->cdevs[index]->owner = driver->owner;
3157 err = cdev_add(driver->cdevs[index], dev, count);
3158 if (err)
3159 kobject_put(&driver->cdevs[index]->kobj);
3160 return err;
3161}
3162
3163/**
3164 * tty_register_device - register a tty device
3165 * @driver: the tty driver that describes the tty device
3166 * @index: the index in the tty driver for this tty device
3167 * @device: a struct device that is associated with this tty device.
3168 * This field is optional, if there is no known struct device
3169 * for this tty device it can be set to NULL safely.
3170 *
3171 * This call is required to be made to register an individual tty device
3172 * if the tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If
3173 * that bit is not set, this function should not be called by a tty
3174 * driver.
3175 *
3176 * Locking: ??
3177 *
3178 * Return: A pointer to the struct device for this tty device (or
3179 * ERR_PTR(-EFOO) on error).
3180 */
3181struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3182 struct device *device)
3183{
3184 return tty_register_device_attr(driver, index, device, NULL, NULL);
3185}
3186EXPORT_SYMBOL(tty_register_device);
3187
3188static void tty_device_create_release(struct device *dev)
3189{
3190 dev_dbg(dev, "releasing...\n");
3191 kfree(dev);
3192}
3193
3194/**
3195 * tty_register_device_attr - register a tty device
3196 * @driver: the tty driver that describes the tty device
3197 * @index: the index in the tty driver for this tty device
3198 * @device: a struct device that is associated with this tty device.
3199 * This field is optional, if there is no known struct device
3200 * for this tty device it can be set to %NULL safely.
3201 * @drvdata: Driver data to be set to device.
3202 * @attr_grp: Attribute group to be set on device.
3203 *
3204 * This call is required to be made to register an individual tty device if the
3205 * tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If that bit is
3206 * not set, this function should not be called by a tty driver.
3207 *
3208 * Locking: ??
3209 *
3210 * Return: A pointer to the struct device for this tty device (or
3211 * ERR_PTR(-EFOO) on error).
3212 */
3213struct device *tty_register_device_attr(struct tty_driver *driver,
3214 unsigned index, struct device *device,
3215 void *drvdata,
3216 const struct attribute_group **attr_grp)
3217{
3218 char name[64];
3219 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3220 struct ktermios *tp;
3221 struct device *dev;
3222 int retval;
3223
3224 if (index >= driver->num) {
3225 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3226 driver->name, index);
3227 return ERR_PTR(-EINVAL);
3228 }
3229
3230 if (driver->type == TTY_DRIVER_TYPE_PTY)
3231 pty_line_name(driver, index, name);
3232 else
3233 tty_line_name(driver, index, name);
3234
3235 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3236 if (!dev)
3237 return ERR_PTR(-ENOMEM);
3238
3239 dev->devt = devt;
3240 dev->class = tty_class;
3241 dev->parent = device;
3242 dev->release = tty_device_create_release;
3243 dev_set_name(dev, "%s", name);
3244 dev->groups = attr_grp;
3245 dev_set_drvdata(dev, drvdata);
3246
3247 dev_set_uevent_suppress(dev, 1);
3248
3249 retval = device_register(dev);
3250 if (retval)
3251 goto err_put;
3252
3253 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3254 /*
3255 * Free any saved termios data so that the termios state is
3256 * reset when reusing a minor number.
3257 */
3258 tp = driver->termios[index];
3259 if (tp) {
3260 driver->termios[index] = NULL;
3261 kfree(tp);
3262 }
3263
3264 retval = tty_cdev_add(driver, devt, index, 1);
3265 if (retval)
3266 goto err_del;
3267 }
3268
3269 dev_set_uevent_suppress(dev, 0);
3270 kobject_uevent(&dev->kobj, KOBJ_ADD);
3271
3272 return dev;
3273
3274err_del:
3275 device_del(dev);
3276err_put:
3277 put_device(dev);
3278
3279 return ERR_PTR(retval);
3280}
3281EXPORT_SYMBOL_GPL(tty_register_device_attr);
3282
3283/**
3284 * tty_unregister_device - unregister a tty device
3285 * @driver: the tty driver that describes the tty device
3286 * @index: the index in the tty driver for this tty device
3287 *
3288 * If a tty device is registered with a call to tty_register_device() then
3289 * this function must be called when the tty device is gone.
3290 *
3291 * Locking: ??
3292 */
3293void tty_unregister_device(struct tty_driver *driver, unsigned index)
3294{
3295 device_destroy(tty_class,
3296 MKDEV(driver->major, driver->minor_start) + index);
3297 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3298 cdev_del(driver->cdevs[index]);
3299 driver->cdevs[index] = NULL;
3300 }
3301}
3302EXPORT_SYMBOL(tty_unregister_device);
3303
3304/**
3305 * __tty_alloc_driver -- allocate tty driver
3306 * @lines: count of lines this driver can handle at most
3307 * @owner: module which is responsible for this driver
3308 * @flags: some of %TTY_DRIVER_ flags, will be set in driver->flags
3309 *
3310 * This should not be called directly, some of the provided macros should be
3311 * used instead. Use IS_ERR() and friends on @retval.
3312 */
3313struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3314 unsigned long flags)
3315{
3316 struct tty_driver *driver;
3317 unsigned int cdevs = 1;
3318 int err;
3319
3320 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3321 return ERR_PTR(-EINVAL);
3322
3323 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
3324 if (!driver)
3325 return ERR_PTR(-ENOMEM);
3326
3327 kref_init(&driver->kref);
3328 driver->num = lines;
3329 driver->owner = owner;
3330 driver->flags = flags;
3331
3332 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3333 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3334 GFP_KERNEL);
3335 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3336 GFP_KERNEL);
3337 if (!driver->ttys || !driver->termios) {
3338 err = -ENOMEM;
3339 goto err_free_all;
3340 }
3341 }
3342
3343 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3344 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3345 GFP_KERNEL);
3346 if (!driver->ports) {
3347 err = -ENOMEM;
3348 goto err_free_all;
3349 }
3350 cdevs = lines;
3351 }
3352
3353 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3354 if (!driver->cdevs) {
3355 err = -ENOMEM;
3356 goto err_free_all;
3357 }
3358
3359 return driver;
3360err_free_all:
3361 kfree(driver->ports);
3362 kfree(driver->ttys);
3363 kfree(driver->termios);
3364 kfree(driver->cdevs);
3365 kfree(driver);
3366 return ERR_PTR(err);
3367}
3368EXPORT_SYMBOL(__tty_alloc_driver);
3369
3370static void destruct_tty_driver(struct kref *kref)
3371{
3372 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3373 int i;
3374 struct ktermios *tp;
3375
3376 if (driver->flags & TTY_DRIVER_INSTALLED) {
3377 for (i = 0; i < driver->num; i++) {
3378 tp = driver->termios[i];
3379 if (tp) {
3380 driver->termios[i] = NULL;
3381 kfree(tp);
3382 }
3383 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3384 tty_unregister_device(driver, i);
3385 }
3386 proc_tty_unregister_driver(driver);
3387 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3388 cdev_del(driver->cdevs[0]);
3389 }
3390 kfree(driver->cdevs);
3391 kfree(driver->ports);
3392 kfree(driver->termios);
3393 kfree(driver->ttys);
3394 kfree(driver);
3395}
3396
3397/**
3398 * tty_driver_kref_put -- drop a reference to a tty driver
3399 * @driver: driver of which to drop the reference
3400 *
3401 * The final put will destroy and free up the driver.
3402 */
3403void tty_driver_kref_put(struct tty_driver *driver)
3404{
3405 kref_put(&driver->kref, destruct_tty_driver);
3406}
3407EXPORT_SYMBOL(tty_driver_kref_put);
3408
3409/**
3410 * tty_register_driver -- register a tty driver
3411 * @driver: driver to register
3412 *
3413 * Called by a tty driver to register itself.
3414 */
3415int tty_register_driver(struct tty_driver *driver)
3416{
3417 int error;
3418 int i;
3419 dev_t dev;
3420 struct device *d;
3421
3422 if (!driver->major) {
3423 error = alloc_chrdev_region(&dev, driver->minor_start,
3424 driver->num, driver->name);
3425 if (!error) {
3426 driver->major = MAJOR(dev);
3427 driver->minor_start = MINOR(dev);
3428 }
3429 } else {
3430 dev = MKDEV(driver->major, driver->minor_start);
3431 error = register_chrdev_region(dev, driver->num, driver->name);
3432 }
3433 if (error < 0)
3434 goto err;
3435
3436 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3437 error = tty_cdev_add(driver, dev, 0, driver->num);
3438 if (error)
3439 goto err_unreg_char;
3440 }
3441
3442 mutex_lock(&tty_mutex);
3443 list_add(&driver->tty_drivers, &tty_drivers);
3444 mutex_unlock(&tty_mutex);
3445
3446 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3447 for (i = 0; i < driver->num; i++) {
3448 d = tty_register_device(driver, i, NULL);
3449 if (IS_ERR(d)) {
3450 error = PTR_ERR(d);
3451 goto err_unreg_devs;
3452 }
3453 }
3454 }
3455 proc_tty_register_driver(driver);
3456 driver->flags |= TTY_DRIVER_INSTALLED;
3457 return 0;
3458
3459err_unreg_devs:
3460 for (i--; i >= 0; i--)
3461 tty_unregister_device(driver, i);
3462
3463 mutex_lock(&tty_mutex);
3464 list_del(&driver->tty_drivers);
3465 mutex_unlock(&tty_mutex);
3466
3467err_unreg_char:
3468 unregister_chrdev_region(dev, driver->num);
3469err:
3470 return error;
3471}
3472EXPORT_SYMBOL(tty_register_driver);
3473
3474/**
3475 * tty_unregister_driver -- unregister a tty driver
3476 * @driver: driver to unregister
3477 *
3478 * Called by a tty driver to unregister itself.
3479 */
3480void tty_unregister_driver(struct tty_driver *driver)
3481{
3482 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3483 driver->num);
3484 mutex_lock(&tty_mutex);
3485 list_del(&driver->tty_drivers);
3486 mutex_unlock(&tty_mutex);
3487}
3488EXPORT_SYMBOL(tty_unregister_driver);
3489
3490dev_t tty_devnum(struct tty_struct *tty)
3491{
3492 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3493}
3494EXPORT_SYMBOL(tty_devnum);
3495
3496void tty_default_fops(struct file_operations *fops)
3497{
3498 *fops = tty_fops;
3499}
3500
3501static char *tty_devnode(const struct device *dev, umode_t *mode)
3502{
3503 if (!mode)
3504 return NULL;
3505 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3506 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3507 *mode = 0666;
3508 return NULL;
3509}
3510
3511static int __init tty_class_init(void)
3512{
3513 tty_class = class_create(THIS_MODULE, "tty");
3514 if (IS_ERR(tty_class))
3515 return PTR_ERR(tty_class);
3516 tty_class->devnode = tty_devnode;
3517 return 0;
3518}
3519
3520postcore_initcall(tty_class_init);
3521
3522/* 3/2004 jmc: why do these devices exist? */
3523static struct cdev tty_cdev, console_cdev;
3524
3525static ssize_t show_cons_active(struct device *dev,
3526 struct device_attribute *attr, char *buf)
3527{
3528 struct console *cs[16];
3529 int i = 0;
3530 struct console *c;
3531 ssize_t count = 0;
3532
3533 /*
3534 * Hold the console_list_lock to guarantee that no consoles are
3535 * unregistered until all console processing is complete.
3536 * This also allows safe traversal of the console list and
3537 * race-free reading of @flags.
3538 */
3539 console_list_lock();
3540
3541 for_each_console(c) {
3542 if (!c->device)
3543 continue;
3544 if (!c->write)
3545 continue;
3546 if ((c->flags & CON_ENABLED) == 0)
3547 continue;
3548 cs[i++] = c;
3549 if (i >= ARRAY_SIZE(cs))
3550 break;
3551 }
3552
3553 /*
3554 * Take console_lock to serialize device() callback with
3555 * other console operations. For example, fg_console is
3556 * modified under console_lock when switching vt.
3557 */
3558 console_lock();
3559 while (i--) {
3560 int index = cs[i]->index;
3561 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3562
3563 /* don't resolve tty0 as some programs depend on it */
3564 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3565 count += tty_line_name(drv, index, buf + count);
3566 else
3567 count += sprintf(buf + count, "%s%d",
3568 cs[i]->name, cs[i]->index);
3569
3570 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3571 }
3572 console_unlock();
3573
3574 console_list_unlock();
3575
3576 return count;
3577}
3578static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3579
3580static struct attribute *cons_dev_attrs[] = {
3581 &dev_attr_active.attr,
3582 NULL
3583};
3584
3585ATTRIBUTE_GROUPS(cons_dev);
3586
3587static struct device *consdev;
3588
3589void console_sysfs_notify(void)
3590{
3591 if (consdev)
3592 sysfs_notify(&consdev->kobj, NULL, "active");
3593}
3594
3595static struct ctl_table tty_table[] = {
3596 {
3597 .procname = "legacy_tiocsti",
3598 .data = &tty_legacy_tiocsti,
3599 .maxlen = sizeof(tty_legacy_tiocsti),
3600 .mode = 0644,
3601 .proc_handler = proc_dobool,
3602 },
3603 {
3604 .procname = "ldisc_autoload",
3605 .data = &tty_ldisc_autoload,
3606 .maxlen = sizeof(tty_ldisc_autoload),
3607 .mode = 0644,
3608 .proc_handler = proc_dointvec,
3609 .extra1 = SYSCTL_ZERO,
3610 .extra2 = SYSCTL_ONE,
3611 },
3612 { }
3613};
3614
3615static struct ctl_table tty_dir_table[] = {
3616 {
3617 .procname = "tty",
3618 .mode = 0555,
3619 .child = tty_table,
3620 },
3621 { }
3622};
3623
3624static struct ctl_table tty_root_table[] = {
3625 {
3626 .procname = "dev",
3627 .mode = 0555,
3628 .child = tty_dir_table,
3629 },
3630 { }
3631};
3632
3633/*
3634 * Ok, now we can initialize the rest of the tty devices and can count
3635 * on memory allocations, interrupts etc..
3636 */
3637int __init tty_init(void)
3638{
3639 register_sysctl_table(tty_root_table);
3640 cdev_init(&tty_cdev, &tty_fops);
3641 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3642 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3643 panic("Couldn't register /dev/tty driver\n");
3644 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3645
3646 cdev_init(&console_cdev, &console_fops);
3647 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3648 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3649 panic("Couldn't register /dev/console driver\n");
3650 consdev = device_create_with_groups(tty_class, NULL,
3651 MKDEV(TTYAUX_MAJOR, 1), NULL,
3652 cons_dev_groups, "console");
3653 if (IS_ERR(consdev))
3654 consdev = NULL;
3655
3656#ifdef CONFIG_VT
3657 vty_init(&console_fops);
3658#endif
3659 return 0;
3660}
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#ifdef TTY_DEBUG_HANGUP
110# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
111#else
112# define tty_debug_hangup(tty, f, args...) do { } while (0)
113#endif
114
115#define TTY_PARANOIA_CHECK 1
116#define CHECK_TTY_COUNT 1
117
118struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
119 .c_iflag = ICRNL | IXON,
120 .c_oflag = OPOST | ONLCR,
121 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
122 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
123 ECHOCTL | ECHOKE | IEXTEN,
124 .c_cc = INIT_C_CC,
125 .c_ispeed = 38400,
126 .c_ospeed = 38400,
127 /* .c_line = N_TTY, */
128};
129
130EXPORT_SYMBOL(tty_std_termios);
131
132/* This list gets poked at by procfs and various bits of boot up code. This
133 could do with some rationalisation such as pulling the tty proc function
134 into this file */
135
136LIST_HEAD(tty_drivers); /* linked list of tty drivers */
137
138/* Mutex to protect creating and releasing a tty */
139DEFINE_MUTEX(tty_mutex);
140
141static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
142static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
143ssize_t redirected_tty_write(struct file *, const char __user *,
144 size_t, loff_t *);
145static unsigned int tty_poll(struct file *, poll_table *);
146static int tty_open(struct inode *, struct file *);
147long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148#ifdef CONFIG_COMPAT
149static long tty_compat_ioctl(struct file *file, unsigned int cmd,
150 unsigned long arg);
151#else
152#define tty_compat_ioctl NULL
153#endif
154static int __tty_fasync(int fd, struct file *filp, int on);
155static int tty_fasync(int fd, struct file *filp, int on);
156static void release_tty(struct tty_struct *tty, int idx);
157
158/**
159 * free_tty_struct - free a disused tty
160 * @tty: tty struct to free
161 *
162 * Free the write buffers, tty queue and tty memory itself.
163 *
164 * Locking: none. Must be called after tty is definitely unused
165 */
166
167static void free_tty_struct(struct tty_struct *tty)
168{
169 tty_ldisc_deinit(tty);
170 put_device(tty->dev);
171 kfree(tty->write_buf);
172 tty->magic = 0xDEADDEAD;
173 kfree(tty);
174}
175
176static inline struct tty_struct *file_tty(struct file *file)
177{
178 return ((struct tty_file_private *)file->private_data)->tty;
179}
180
181int tty_alloc_file(struct file *file)
182{
183 struct tty_file_private *priv;
184
185 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
186 if (!priv)
187 return -ENOMEM;
188
189 file->private_data = priv;
190
191 return 0;
192}
193
194/* Associate a new file with the tty structure */
195void tty_add_file(struct tty_struct *tty, struct file *file)
196{
197 struct tty_file_private *priv = file->private_data;
198
199 priv->tty = tty;
200 priv->file = file;
201
202 spin_lock(&tty->files_lock);
203 list_add(&priv->list, &tty->tty_files);
204 spin_unlock(&tty->files_lock);
205}
206
207/**
208 * tty_free_file - free file->private_data
209 *
210 * This shall be used only for fail path handling when tty_add_file was not
211 * called yet.
212 */
213void tty_free_file(struct file *file)
214{
215 struct tty_file_private *priv = file->private_data;
216
217 file->private_data = NULL;
218 kfree(priv);
219}
220
221/* Delete file from its tty */
222static void tty_del_file(struct file *file)
223{
224 struct tty_file_private *priv = file->private_data;
225 struct tty_struct *tty = priv->tty;
226
227 spin_lock(&tty->files_lock);
228 list_del(&priv->list);
229 spin_unlock(&tty->files_lock);
230 tty_free_file(file);
231}
232
233
234#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
235
236/**
237 * tty_name - return tty naming
238 * @tty: tty structure
239 *
240 * Convert a tty structure into a name. The name reflects the kernel
241 * naming policy and if udev is in use may not reflect user space
242 *
243 * Locking: none
244 */
245
246const char *tty_name(const struct tty_struct *tty)
247{
248 if (!tty) /* Hmm. NULL pointer. That's fun. */
249 return "NULL tty";
250 return tty->name;
251}
252
253EXPORT_SYMBOL(tty_name);
254
255const char *tty_driver_name(const struct tty_struct *tty)
256{
257 if (!tty || !tty->driver)
258 return "";
259 return tty->driver->name;
260}
261
262static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
263 const char *routine)
264{
265#ifdef TTY_PARANOIA_CHECK
266 if (!tty) {
267 pr_warn("(%d:%d): %s: NULL tty\n",
268 imajor(inode), iminor(inode), routine);
269 return 1;
270 }
271 if (tty->magic != TTY_MAGIC) {
272 pr_warn("(%d:%d): %s: bad magic number\n",
273 imajor(inode), iminor(inode), routine);
274 return 1;
275 }
276#endif
277 return 0;
278}
279
280/* Caller must hold tty_lock */
281static int check_tty_count(struct tty_struct *tty, const char *routine)
282{
283#ifdef CHECK_TTY_COUNT
284 struct list_head *p;
285 int count = 0;
286
287 spin_lock(&tty->files_lock);
288 list_for_each(p, &tty->tty_files) {
289 count++;
290 }
291 spin_unlock(&tty->files_lock);
292 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
293 tty->driver->subtype == PTY_TYPE_SLAVE &&
294 tty->link && tty->link->count)
295 count++;
296 if (tty->count != count) {
297 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
298 routine, tty->count, count);
299 return count;
300 }
301#endif
302 return 0;
303}
304
305/**
306 * get_tty_driver - find device of a tty
307 * @dev_t: device identifier
308 * @index: returns the index of the tty
309 *
310 * This routine returns a tty driver structure, given a device number
311 * and also passes back the index number.
312 *
313 * Locking: caller must hold tty_mutex
314 */
315
316static struct tty_driver *get_tty_driver(dev_t device, int *index)
317{
318 struct tty_driver *p;
319
320 list_for_each_entry(p, &tty_drivers, tty_drivers) {
321 dev_t base = MKDEV(p->major, p->minor_start);
322 if (device < base || device >= base + p->num)
323 continue;
324 *index = device - base;
325 return tty_driver_kref_get(p);
326 }
327 return NULL;
328}
329
330#ifdef CONFIG_CONSOLE_POLL
331
332/**
333 * tty_find_polling_driver - find device of a polled tty
334 * @name: name string to match
335 * @line: pointer to resulting tty line nr
336 *
337 * This routine returns a tty driver structure, given a name
338 * and the condition that the tty driver is capable of polled
339 * operation.
340 */
341struct tty_driver *tty_find_polling_driver(char *name, int *line)
342{
343 struct tty_driver *p, *res = NULL;
344 int tty_line = 0;
345 int len;
346 char *str, *stp;
347
348 for (str = name; *str; str++)
349 if ((*str >= '0' && *str <= '9') || *str == ',')
350 break;
351 if (!*str)
352 return NULL;
353
354 len = str - name;
355 tty_line = simple_strtoul(str, &str, 10);
356
357 mutex_lock(&tty_mutex);
358 /* Search through the tty devices to look for a match */
359 list_for_each_entry(p, &tty_drivers, tty_drivers) {
360 if (strncmp(name, p->name, len) != 0)
361 continue;
362 stp = str;
363 if (*stp == ',')
364 stp++;
365 if (*stp == '\0')
366 stp = NULL;
367
368 if (tty_line >= 0 && tty_line < p->num && p->ops &&
369 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
370 res = tty_driver_kref_get(p);
371 *line = tty_line;
372 break;
373 }
374 }
375 mutex_unlock(&tty_mutex);
376
377 return res;
378}
379EXPORT_SYMBOL_GPL(tty_find_polling_driver);
380#endif
381
382static int is_ignored(int sig)
383{
384 return (sigismember(¤t->blocked, sig) ||
385 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
386}
387
388/**
389 * tty_check_change - check for POSIX terminal changes
390 * @tty: tty to check
391 *
392 * If we try to write to, or set the state of, a terminal and we're
393 * not in the foreground, send a SIGTTOU. If the signal is blocked or
394 * ignored, go ahead and perform the operation. (POSIX 7.2)
395 *
396 * Locking: ctrl_lock
397 */
398
399int __tty_check_change(struct tty_struct *tty, int sig)
400{
401 unsigned long flags;
402 struct pid *pgrp, *tty_pgrp;
403 int ret = 0;
404
405 if (current->signal->tty != tty)
406 return 0;
407
408 rcu_read_lock();
409 pgrp = task_pgrp(current);
410
411 spin_lock_irqsave(&tty->ctrl_lock, flags);
412 tty_pgrp = tty->pgrp;
413 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
414
415 if (tty_pgrp && pgrp != tty->pgrp) {
416 if (is_ignored(sig)) {
417 if (sig == SIGTTIN)
418 ret = -EIO;
419 } else if (is_current_pgrp_orphaned())
420 ret = -EIO;
421 else {
422 kill_pgrp(pgrp, sig, 1);
423 set_thread_flag(TIF_SIGPENDING);
424 ret = -ERESTARTSYS;
425 }
426 }
427 rcu_read_unlock();
428
429 if (!tty_pgrp)
430 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
431
432 return ret;
433}
434
435int tty_check_change(struct tty_struct *tty)
436{
437 return __tty_check_change(tty, SIGTTOU);
438}
439EXPORT_SYMBOL(tty_check_change);
440
441static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
442 size_t count, loff_t *ppos)
443{
444 return 0;
445}
446
447static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
448 size_t count, loff_t *ppos)
449{
450 return -EIO;
451}
452
453/* No kernel lock held - none needed ;) */
454static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
455{
456 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
457}
458
459static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
460 unsigned long arg)
461{
462 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
463}
464
465static long hung_up_tty_compat_ioctl(struct file *file,
466 unsigned int cmd, unsigned long arg)
467{
468 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
469}
470
471static int hung_up_tty_fasync(int fd, struct file *file, int on)
472{
473 return -ENOTTY;
474}
475
476static const struct file_operations tty_fops = {
477 .llseek = no_llseek,
478 .read = tty_read,
479 .write = tty_write,
480 .poll = tty_poll,
481 .unlocked_ioctl = tty_ioctl,
482 .compat_ioctl = tty_compat_ioctl,
483 .open = tty_open,
484 .release = tty_release,
485 .fasync = tty_fasync,
486};
487
488static const struct file_operations console_fops = {
489 .llseek = no_llseek,
490 .read = tty_read,
491 .write = redirected_tty_write,
492 .poll = tty_poll,
493 .unlocked_ioctl = tty_ioctl,
494 .compat_ioctl = tty_compat_ioctl,
495 .open = tty_open,
496 .release = tty_release,
497 .fasync = tty_fasync,
498};
499
500static const struct file_operations hung_up_tty_fops = {
501 .llseek = no_llseek,
502 .read = hung_up_tty_read,
503 .write = hung_up_tty_write,
504 .poll = hung_up_tty_poll,
505 .unlocked_ioctl = hung_up_tty_ioctl,
506 .compat_ioctl = hung_up_tty_compat_ioctl,
507 .release = tty_release,
508 .fasync = hung_up_tty_fasync,
509};
510
511static DEFINE_SPINLOCK(redirect_lock);
512static struct file *redirect;
513
514
515void proc_clear_tty(struct task_struct *p)
516{
517 unsigned long flags;
518 struct tty_struct *tty;
519 spin_lock_irqsave(&p->sighand->siglock, flags);
520 tty = p->signal->tty;
521 p->signal->tty = NULL;
522 spin_unlock_irqrestore(&p->sighand->siglock, flags);
523 tty_kref_put(tty);
524}
525
526/**
527 * proc_set_tty - set the controlling terminal
528 *
529 * Only callable by the session leader and only if it does not already have
530 * a controlling terminal.
531 *
532 * Caller must hold: tty_lock()
533 * a readlock on tasklist_lock
534 * sighand lock
535 */
536static void __proc_set_tty(struct tty_struct *tty)
537{
538 unsigned long flags;
539
540 spin_lock_irqsave(&tty->ctrl_lock, flags);
541 /*
542 * The session and fg pgrp references will be non-NULL if
543 * tiocsctty() is stealing the controlling tty
544 */
545 put_pid(tty->session);
546 put_pid(tty->pgrp);
547 tty->pgrp = get_pid(task_pgrp(current));
548 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
549 tty->session = get_pid(task_session(current));
550 if (current->signal->tty) {
551 tty_debug(tty, "current tty %s not NULL!!\n",
552 current->signal->tty->name);
553 tty_kref_put(current->signal->tty);
554 }
555 put_pid(current->signal->tty_old_pgrp);
556 current->signal->tty = tty_kref_get(tty);
557 current->signal->tty_old_pgrp = NULL;
558}
559
560static void proc_set_tty(struct tty_struct *tty)
561{
562 spin_lock_irq(¤t->sighand->siglock);
563 __proc_set_tty(tty);
564 spin_unlock_irq(¤t->sighand->siglock);
565}
566
567struct tty_struct *get_current_tty(void)
568{
569 struct tty_struct *tty;
570 unsigned long flags;
571
572 spin_lock_irqsave(¤t->sighand->siglock, flags);
573 tty = tty_kref_get(current->signal->tty);
574 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
575 return tty;
576}
577EXPORT_SYMBOL_GPL(get_current_tty);
578
579static void session_clear_tty(struct pid *session)
580{
581 struct task_struct *p;
582 do_each_pid_task(session, PIDTYPE_SID, p) {
583 proc_clear_tty(p);
584 } while_each_pid_task(session, PIDTYPE_SID, p);
585}
586
587/**
588 * tty_wakeup - request more data
589 * @tty: terminal
590 *
591 * Internal and external helper for wakeups of tty. This function
592 * informs the line discipline if present that the driver is ready
593 * to receive more output data.
594 */
595
596void tty_wakeup(struct tty_struct *tty)
597{
598 struct tty_ldisc *ld;
599
600 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
601 ld = tty_ldisc_ref(tty);
602 if (ld) {
603 if (ld->ops->write_wakeup)
604 ld->ops->write_wakeup(tty);
605 tty_ldisc_deref(ld);
606 }
607 }
608 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
609}
610
611EXPORT_SYMBOL_GPL(tty_wakeup);
612
613/**
614 * tty_signal_session_leader - sends SIGHUP to session leader
615 * @tty controlling tty
616 * @exit_session if non-zero, signal all foreground group processes
617 *
618 * Send SIGHUP and SIGCONT to the session leader and its process group.
619 * Optionally, signal all processes in the foreground process group.
620 *
621 * Returns the number of processes in the session with this tty
622 * as their controlling terminal. This value is used to drop
623 * tty references for those processes.
624 */
625static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
626{
627 struct task_struct *p;
628 int refs = 0;
629 struct pid *tty_pgrp = NULL;
630
631 read_lock(&tasklist_lock);
632 if (tty->session) {
633 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
634 spin_lock_irq(&p->sighand->siglock);
635 if (p->signal->tty == tty) {
636 p->signal->tty = NULL;
637 /* We defer the dereferences outside fo
638 the tasklist lock */
639 refs++;
640 }
641 if (!p->signal->leader) {
642 spin_unlock_irq(&p->sighand->siglock);
643 continue;
644 }
645 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
646 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
647 put_pid(p->signal->tty_old_pgrp); /* A noop */
648 spin_lock(&tty->ctrl_lock);
649 tty_pgrp = get_pid(tty->pgrp);
650 if (tty->pgrp)
651 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
652 spin_unlock(&tty->ctrl_lock);
653 spin_unlock_irq(&p->sighand->siglock);
654 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
655 }
656 read_unlock(&tasklist_lock);
657
658 if (tty_pgrp) {
659 if (exit_session)
660 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
661 put_pid(tty_pgrp);
662 }
663
664 return refs;
665}
666
667/**
668 * __tty_hangup - actual handler for hangup events
669 * @work: tty device
670 *
671 * This can be called by a "kworker" kernel thread. That is process
672 * synchronous but doesn't hold any locks, so we need to make sure we
673 * have the appropriate locks for what we're doing.
674 *
675 * The hangup event clears any pending redirections onto the hung up
676 * device. It ensures future writes will error and it does the needed
677 * line discipline hangup and signal delivery. The tty object itself
678 * remains intact.
679 *
680 * Locking:
681 * BTM
682 * redirect lock for undoing redirection
683 * file list lock for manipulating list of ttys
684 * tty_ldiscs_lock from called functions
685 * termios_rwsem resetting termios data
686 * tasklist_lock to walk task list for hangup event
687 * ->siglock to protect ->signal/->sighand
688 */
689static void __tty_hangup(struct tty_struct *tty, int exit_session)
690{
691 struct file *cons_filp = NULL;
692 struct file *filp, *f = NULL;
693 struct tty_file_private *priv;
694 int closecount = 0, n;
695 int refs;
696
697 if (!tty)
698 return;
699
700
701 spin_lock(&redirect_lock);
702 if (redirect && file_tty(redirect) == tty) {
703 f = redirect;
704 redirect = NULL;
705 }
706 spin_unlock(&redirect_lock);
707
708 tty_lock(tty);
709
710 if (test_bit(TTY_HUPPED, &tty->flags)) {
711 tty_unlock(tty);
712 return;
713 }
714
715 /* inuse_filps is protected by the single tty lock,
716 this really needs to change if we want to flush the
717 workqueue with the lock held */
718 check_tty_count(tty, "tty_hangup");
719
720 spin_lock(&tty->files_lock);
721 /* This breaks for file handles being sent over AF_UNIX sockets ? */
722 list_for_each_entry(priv, &tty->tty_files, list) {
723 filp = priv->file;
724 if (filp->f_op->write == redirected_tty_write)
725 cons_filp = filp;
726 if (filp->f_op->write != tty_write)
727 continue;
728 closecount++;
729 __tty_fasync(-1, filp, 0); /* can't block */
730 filp->f_op = &hung_up_tty_fops;
731 }
732 spin_unlock(&tty->files_lock);
733
734 refs = tty_signal_session_leader(tty, exit_session);
735 /* Account for the p->signal references we killed */
736 while (refs--)
737 tty_kref_put(tty);
738
739 tty_ldisc_hangup(tty, cons_filp != NULL);
740
741 spin_lock_irq(&tty->ctrl_lock);
742 clear_bit(TTY_THROTTLED, &tty->flags);
743 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
744 put_pid(tty->session);
745 put_pid(tty->pgrp);
746 tty->session = NULL;
747 tty->pgrp = NULL;
748 tty->ctrl_status = 0;
749 spin_unlock_irq(&tty->ctrl_lock);
750
751 /*
752 * If one of the devices matches a console pointer, we
753 * cannot just call hangup() because that will cause
754 * tty->count and state->count to go out of sync.
755 * So we just call close() the right number of times.
756 */
757 if (cons_filp) {
758 if (tty->ops->close)
759 for (n = 0; n < closecount; n++)
760 tty->ops->close(tty, cons_filp);
761 } else if (tty->ops->hangup)
762 tty->ops->hangup(tty);
763 /*
764 * We don't want to have driver/ldisc interactions beyond the ones
765 * we did here. The driver layer expects no calls after ->hangup()
766 * from the ldisc side, which is now guaranteed.
767 */
768 set_bit(TTY_HUPPED, &tty->flags);
769 tty_unlock(tty);
770
771 if (f)
772 fput(f);
773}
774
775static void do_tty_hangup(struct work_struct *work)
776{
777 struct tty_struct *tty =
778 container_of(work, struct tty_struct, hangup_work);
779
780 __tty_hangup(tty, 0);
781}
782
783/**
784 * tty_hangup - trigger a hangup event
785 * @tty: tty to hangup
786 *
787 * A carrier loss (virtual or otherwise) has occurred on this like
788 * schedule a hangup sequence to run after this event.
789 */
790
791void tty_hangup(struct tty_struct *tty)
792{
793 tty_debug_hangup(tty, "hangup\n");
794 schedule_work(&tty->hangup_work);
795}
796
797EXPORT_SYMBOL(tty_hangup);
798
799/**
800 * tty_vhangup - process vhangup
801 * @tty: tty to hangup
802 *
803 * The user has asked via system call for the terminal to be hung up.
804 * We do this synchronously so that when the syscall returns the process
805 * is complete. That guarantee is necessary for security reasons.
806 */
807
808void tty_vhangup(struct tty_struct *tty)
809{
810 tty_debug_hangup(tty, "vhangup\n");
811 __tty_hangup(tty, 0);
812}
813
814EXPORT_SYMBOL(tty_vhangup);
815
816
817/**
818 * tty_vhangup_self - process vhangup for own ctty
819 *
820 * Perform a vhangup on the current controlling tty
821 */
822
823void tty_vhangup_self(void)
824{
825 struct tty_struct *tty;
826
827 tty = get_current_tty();
828 if (tty) {
829 tty_vhangup(tty);
830 tty_kref_put(tty);
831 }
832}
833
834/**
835 * tty_vhangup_session - hangup session leader exit
836 * @tty: tty to hangup
837 *
838 * The session leader is exiting and hanging up its controlling terminal.
839 * Every process in the foreground process group is signalled SIGHUP.
840 *
841 * We do this synchronously so that when the syscall returns the process
842 * is complete. That guarantee is necessary for security reasons.
843 */
844
845static void tty_vhangup_session(struct tty_struct *tty)
846{
847 tty_debug_hangup(tty, "session hangup\n");
848 __tty_hangup(tty, 1);
849}
850
851/**
852 * tty_hung_up_p - was tty hung up
853 * @filp: file pointer of tty
854 *
855 * Return true if the tty has been subject to a vhangup or a carrier
856 * loss
857 */
858
859int tty_hung_up_p(struct file *filp)
860{
861 return (filp->f_op == &hung_up_tty_fops);
862}
863
864EXPORT_SYMBOL(tty_hung_up_p);
865
866/**
867 * disassociate_ctty - disconnect controlling tty
868 * @on_exit: true if exiting so need to "hang up" the session
869 *
870 * This function is typically called only by the session leader, when
871 * it wants to disassociate itself from its controlling tty.
872 *
873 * It performs the following functions:
874 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
875 * (2) Clears the tty from being controlling the session
876 * (3) Clears the controlling tty for all processes in the
877 * session group.
878 *
879 * The argument on_exit is set to 1 if called when a process is
880 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
881 *
882 * Locking:
883 * BTM is taken for hysterical raisins, and held when
884 * called from no_tty().
885 * tty_mutex is taken to protect tty
886 * ->siglock is taken to protect ->signal/->sighand
887 * tasklist_lock is taken to walk process list for sessions
888 * ->siglock is taken to protect ->signal/->sighand
889 */
890
891void disassociate_ctty(int on_exit)
892{
893 struct tty_struct *tty;
894
895 if (!current->signal->leader)
896 return;
897
898 tty = get_current_tty();
899 if (tty) {
900 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
901 tty_vhangup_session(tty);
902 } else {
903 struct pid *tty_pgrp = tty_get_pgrp(tty);
904 if (tty_pgrp) {
905 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
906 if (!on_exit)
907 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
908 put_pid(tty_pgrp);
909 }
910 }
911 tty_kref_put(tty);
912
913 } else if (on_exit) {
914 struct pid *old_pgrp;
915 spin_lock_irq(¤t->sighand->siglock);
916 old_pgrp = current->signal->tty_old_pgrp;
917 current->signal->tty_old_pgrp = NULL;
918 spin_unlock_irq(¤t->sighand->siglock);
919 if (old_pgrp) {
920 kill_pgrp(old_pgrp, SIGHUP, on_exit);
921 kill_pgrp(old_pgrp, SIGCONT, on_exit);
922 put_pid(old_pgrp);
923 }
924 return;
925 }
926
927 spin_lock_irq(¤t->sighand->siglock);
928 put_pid(current->signal->tty_old_pgrp);
929 current->signal->tty_old_pgrp = NULL;
930
931 tty = tty_kref_get(current->signal->tty);
932 if (tty) {
933 unsigned long flags;
934 spin_lock_irqsave(&tty->ctrl_lock, flags);
935 put_pid(tty->session);
936 put_pid(tty->pgrp);
937 tty->session = NULL;
938 tty->pgrp = NULL;
939 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
940 tty_kref_put(tty);
941 } else
942 tty_debug_hangup(tty, "no current tty\n");
943
944 spin_unlock_irq(¤t->sighand->siglock);
945 /* Now clear signal->tty under the lock */
946 read_lock(&tasklist_lock);
947 session_clear_tty(task_session(current));
948 read_unlock(&tasklist_lock);
949}
950
951/**
952 *
953 * no_tty - Ensure the current process does not have a controlling tty
954 */
955void no_tty(void)
956{
957 /* FIXME: Review locking here. The tty_lock never covered any race
958 between a new association and proc_clear_tty but possible we need
959 to protect against this anyway */
960 struct task_struct *tsk = current;
961 disassociate_ctty(0);
962 proc_clear_tty(tsk);
963}
964
965
966/**
967 * stop_tty - propagate flow control
968 * @tty: tty to stop
969 *
970 * Perform flow control to the driver. May be called
971 * on an already stopped device and will not re-call the driver
972 * method.
973 *
974 * This functionality is used by both the line disciplines for
975 * halting incoming flow and by the driver. It may therefore be
976 * called from any context, may be under the tty atomic_write_lock
977 * but not always.
978 *
979 * Locking:
980 * flow_lock
981 */
982
983void __stop_tty(struct tty_struct *tty)
984{
985 if (tty->stopped)
986 return;
987 tty->stopped = 1;
988 if (tty->ops->stop)
989 tty->ops->stop(tty);
990}
991
992void stop_tty(struct tty_struct *tty)
993{
994 unsigned long flags;
995
996 spin_lock_irqsave(&tty->flow_lock, flags);
997 __stop_tty(tty);
998 spin_unlock_irqrestore(&tty->flow_lock, flags);
999}
1000EXPORT_SYMBOL(stop_tty);
1001
1002/**
1003 * start_tty - propagate flow control
1004 * @tty: tty to start
1005 *
1006 * Start a tty that has been stopped if at all possible. If this
1007 * tty was previous stopped and is now being started, the driver
1008 * start method is invoked and the line discipline woken.
1009 *
1010 * Locking:
1011 * flow_lock
1012 */
1013
1014void __start_tty(struct tty_struct *tty)
1015{
1016 if (!tty->stopped || tty->flow_stopped)
1017 return;
1018 tty->stopped = 0;
1019 if (tty->ops->start)
1020 tty->ops->start(tty);
1021 tty_wakeup(tty);
1022}
1023
1024void start_tty(struct tty_struct *tty)
1025{
1026 unsigned long flags;
1027
1028 spin_lock_irqsave(&tty->flow_lock, flags);
1029 __start_tty(tty);
1030 spin_unlock_irqrestore(&tty->flow_lock, flags);
1031}
1032EXPORT_SYMBOL(start_tty);
1033
1034static void tty_update_time(struct timespec *time)
1035{
1036 unsigned long sec = get_seconds();
1037
1038 /*
1039 * We only care if the two values differ in anything other than the
1040 * lower three bits (i.e every 8 seconds). If so, then we can update
1041 * the time of the tty device, otherwise it could be construded as a
1042 * security leak to let userspace know the exact timing of the tty.
1043 */
1044 if ((sec ^ time->tv_sec) & ~7)
1045 time->tv_sec = sec;
1046}
1047
1048/**
1049 * tty_read - read method for tty device files
1050 * @file: pointer to tty file
1051 * @buf: user buffer
1052 * @count: size of user buffer
1053 * @ppos: unused
1054 *
1055 * Perform the read system call function on this terminal device. Checks
1056 * for hung up devices before calling the line discipline method.
1057 *
1058 * Locking:
1059 * Locks the line discipline internally while needed. Multiple
1060 * read calls may be outstanding in parallel.
1061 */
1062
1063static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1064 loff_t *ppos)
1065{
1066 int i;
1067 struct inode *inode = file_inode(file);
1068 struct tty_struct *tty = file_tty(file);
1069 struct tty_ldisc *ld;
1070
1071 if (tty_paranoia_check(tty, inode, "tty_read"))
1072 return -EIO;
1073 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1074 return -EIO;
1075
1076 /* We want to wait for the line discipline to sort out in this
1077 situation */
1078 ld = tty_ldisc_ref_wait(tty);
1079 if (!ld)
1080 return hung_up_tty_read(file, buf, count, ppos);
1081 if (ld->ops->read)
1082 i = ld->ops->read(tty, file, buf, count);
1083 else
1084 i = -EIO;
1085 tty_ldisc_deref(ld);
1086
1087 if (i > 0)
1088 tty_update_time(&inode->i_atime);
1089
1090 return i;
1091}
1092
1093static void tty_write_unlock(struct tty_struct *tty)
1094{
1095 mutex_unlock(&tty->atomic_write_lock);
1096 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1097}
1098
1099static int tty_write_lock(struct tty_struct *tty, int ndelay)
1100{
1101 if (!mutex_trylock(&tty->atomic_write_lock)) {
1102 if (ndelay)
1103 return -EAGAIN;
1104 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1105 return -ERESTARTSYS;
1106 }
1107 return 0;
1108}
1109
1110/*
1111 * Split writes up in sane blocksizes to avoid
1112 * denial-of-service type attacks
1113 */
1114static inline ssize_t do_tty_write(
1115 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1116 struct tty_struct *tty,
1117 struct file *file,
1118 const char __user *buf,
1119 size_t count)
1120{
1121 ssize_t ret, written = 0;
1122 unsigned int chunk;
1123
1124 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1125 if (ret < 0)
1126 return ret;
1127
1128 /*
1129 * We chunk up writes into a temporary buffer. This
1130 * simplifies low-level drivers immensely, since they
1131 * don't have locking issues and user mode accesses.
1132 *
1133 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1134 * big chunk-size..
1135 *
1136 * The default chunk-size is 2kB, because the NTTY
1137 * layer has problems with bigger chunks. It will
1138 * claim to be able to handle more characters than
1139 * it actually does.
1140 *
1141 * FIXME: This can probably go away now except that 64K chunks
1142 * are too likely to fail unless switched to vmalloc...
1143 */
1144 chunk = 2048;
1145 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1146 chunk = 65536;
1147 if (count < chunk)
1148 chunk = count;
1149
1150 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1151 if (tty->write_cnt < chunk) {
1152 unsigned char *buf_chunk;
1153
1154 if (chunk < 1024)
1155 chunk = 1024;
1156
1157 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1158 if (!buf_chunk) {
1159 ret = -ENOMEM;
1160 goto out;
1161 }
1162 kfree(tty->write_buf);
1163 tty->write_cnt = chunk;
1164 tty->write_buf = buf_chunk;
1165 }
1166
1167 /* Do the write .. */
1168 for (;;) {
1169 size_t size = count;
1170 if (size > chunk)
1171 size = chunk;
1172 ret = -EFAULT;
1173 if (copy_from_user(tty->write_buf, buf, size))
1174 break;
1175 ret = write(tty, file, tty->write_buf, size);
1176 if (ret <= 0)
1177 break;
1178 written += ret;
1179 buf += ret;
1180 count -= ret;
1181 if (!count)
1182 break;
1183 ret = -ERESTARTSYS;
1184 if (signal_pending(current))
1185 break;
1186 cond_resched();
1187 }
1188 if (written) {
1189 tty_update_time(&file_inode(file)->i_mtime);
1190 ret = written;
1191 }
1192out:
1193 tty_write_unlock(tty);
1194 return ret;
1195}
1196
1197/**
1198 * tty_write_message - write a message to a certain tty, not just the console.
1199 * @tty: the destination tty_struct
1200 * @msg: the message to write
1201 *
1202 * This is used for messages that need to be redirected to a specific tty.
1203 * We don't put it into the syslog queue right now maybe in the future if
1204 * really needed.
1205 *
1206 * We must still hold the BTM and test the CLOSING flag for the moment.
1207 */
1208
1209void tty_write_message(struct tty_struct *tty, char *msg)
1210{
1211 if (tty) {
1212 mutex_lock(&tty->atomic_write_lock);
1213 tty_lock(tty);
1214 if (tty->ops->write && tty->count > 0)
1215 tty->ops->write(tty, msg, strlen(msg));
1216 tty_unlock(tty);
1217 tty_write_unlock(tty);
1218 }
1219 return;
1220}
1221
1222
1223/**
1224 * tty_write - write method for tty device file
1225 * @file: tty file pointer
1226 * @buf: user data to write
1227 * @count: bytes to write
1228 * @ppos: unused
1229 *
1230 * Write data to a tty device via the line discipline.
1231 *
1232 * Locking:
1233 * Locks the line discipline as required
1234 * Writes to the tty driver are serialized by the atomic_write_lock
1235 * and are then processed in chunks to the device. The line discipline
1236 * write method will not be invoked in parallel for each device.
1237 */
1238
1239static ssize_t tty_write(struct file *file, const char __user *buf,
1240 size_t count, loff_t *ppos)
1241{
1242 struct tty_struct *tty = file_tty(file);
1243 struct tty_ldisc *ld;
1244 ssize_t ret;
1245
1246 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1247 return -EIO;
1248 if (!tty || !tty->ops->write ||
1249 (test_bit(TTY_IO_ERROR, &tty->flags)))
1250 return -EIO;
1251 /* Short term debug to catch buggy drivers */
1252 if (tty->ops->write_room == NULL)
1253 tty_err(tty, "missing write_room method\n");
1254 ld = tty_ldisc_ref_wait(tty);
1255 if (!ld)
1256 return hung_up_tty_write(file, buf, count, ppos);
1257 if (!ld->ops->write)
1258 ret = -EIO;
1259 else
1260 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1261 tty_ldisc_deref(ld);
1262 return ret;
1263}
1264
1265ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1266 size_t count, loff_t *ppos)
1267{
1268 struct file *p = NULL;
1269
1270 spin_lock(&redirect_lock);
1271 if (redirect)
1272 p = get_file(redirect);
1273 spin_unlock(&redirect_lock);
1274
1275 if (p) {
1276 ssize_t res;
1277 res = vfs_write(p, buf, count, &p->f_pos);
1278 fput(p);
1279 return res;
1280 }
1281 return tty_write(file, buf, count, ppos);
1282}
1283
1284/**
1285 * tty_send_xchar - send priority character
1286 *
1287 * Send a high priority character to the tty even if stopped
1288 *
1289 * Locking: none for xchar method, write ordering for write method.
1290 */
1291
1292int tty_send_xchar(struct tty_struct *tty, char ch)
1293{
1294 int was_stopped = tty->stopped;
1295
1296 if (tty->ops->send_xchar) {
1297 down_read(&tty->termios_rwsem);
1298 tty->ops->send_xchar(tty, ch);
1299 up_read(&tty->termios_rwsem);
1300 return 0;
1301 }
1302
1303 if (tty_write_lock(tty, 0) < 0)
1304 return -ERESTARTSYS;
1305
1306 down_read(&tty->termios_rwsem);
1307 if (was_stopped)
1308 start_tty(tty);
1309 tty->ops->write(tty, &ch, 1);
1310 if (was_stopped)
1311 stop_tty(tty);
1312 up_read(&tty->termios_rwsem);
1313 tty_write_unlock(tty);
1314 return 0;
1315}
1316
1317static char ptychar[] = "pqrstuvwxyzabcde";
1318
1319/**
1320 * pty_line_name - generate name for a pty
1321 * @driver: the tty driver in use
1322 * @index: the minor number
1323 * @p: output buffer of at least 6 bytes
1324 *
1325 * Generate a name from a driver reference and write it to the output
1326 * buffer.
1327 *
1328 * Locking: None
1329 */
1330static void pty_line_name(struct tty_driver *driver, int index, char *p)
1331{
1332 int i = index + driver->name_base;
1333 /* ->name is initialized to "ttyp", but "tty" is expected */
1334 sprintf(p, "%s%c%x",
1335 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1336 ptychar[i >> 4 & 0xf], i & 0xf);
1337}
1338
1339/**
1340 * tty_line_name - generate name for a tty
1341 * @driver: the tty driver in use
1342 * @index: the minor number
1343 * @p: output buffer of at least 7 bytes
1344 *
1345 * Generate a name from a driver reference and write it to the output
1346 * buffer.
1347 *
1348 * Locking: None
1349 */
1350static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1351{
1352 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1353 return sprintf(p, "%s", driver->name);
1354 else
1355 return sprintf(p, "%s%d", driver->name,
1356 index + driver->name_base);
1357}
1358
1359/**
1360 * tty_driver_lookup_tty() - find an existing tty, if any
1361 * @driver: the driver for the tty
1362 * @idx: the minor number
1363 *
1364 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1365 * driver lookup() method returns an error.
1366 *
1367 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1368 */
1369static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1370 struct file *file, int idx)
1371{
1372 struct tty_struct *tty;
1373
1374 if (driver->ops->lookup)
1375 tty = driver->ops->lookup(driver, file, idx);
1376 else
1377 tty = driver->ttys[idx];
1378
1379 if (!IS_ERR(tty))
1380 tty_kref_get(tty);
1381 return tty;
1382}
1383
1384/**
1385 * tty_init_termios - helper for termios setup
1386 * @tty: the tty to set up
1387 *
1388 * Initialise the termios structures for this tty. Thus runs under
1389 * the tty_mutex currently so we can be relaxed about ordering.
1390 */
1391
1392void tty_init_termios(struct tty_struct *tty)
1393{
1394 struct ktermios *tp;
1395 int idx = tty->index;
1396
1397 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1398 tty->termios = tty->driver->init_termios;
1399 else {
1400 /* Check for lazy saved data */
1401 tp = tty->driver->termios[idx];
1402 if (tp != NULL) {
1403 tty->termios = *tp;
1404 tty->termios.c_line = tty->driver->init_termios.c_line;
1405 } else
1406 tty->termios = tty->driver->init_termios;
1407 }
1408 /* Compatibility until drivers always set this */
1409 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1410 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1411}
1412EXPORT_SYMBOL_GPL(tty_init_termios);
1413
1414int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1415{
1416 tty_init_termios(tty);
1417 tty_driver_kref_get(driver);
1418 tty->count++;
1419 driver->ttys[tty->index] = tty;
1420 return 0;
1421}
1422EXPORT_SYMBOL_GPL(tty_standard_install);
1423
1424/**
1425 * tty_driver_install_tty() - install a tty entry in the driver
1426 * @driver: the driver for the tty
1427 * @tty: the tty
1428 *
1429 * Install a tty object into the driver tables. The tty->index field
1430 * will be set by the time this is called. This method is responsible
1431 * for ensuring any need additional structures are allocated and
1432 * configured.
1433 *
1434 * Locking: tty_mutex for now
1435 */
1436static int tty_driver_install_tty(struct tty_driver *driver,
1437 struct tty_struct *tty)
1438{
1439 return driver->ops->install ? driver->ops->install(driver, tty) :
1440 tty_standard_install(driver, tty);
1441}
1442
1443/**
1444 * tty_driver_remove_tty() - remove a tty from the driver tables
1445 * @driver: the driver for the tty
1446 * @idx: the minor number
1447 *
1448 * Remvoe a tty object from the driver tables. The tty->index field
1449 * will be set by the time this is called.
1450 *
1451 * Locking: tty_mutex for now
1452 */
1453static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1454{
1455 if (driver->ops->remove)
1456 driver->ops->remove(driver, tty);
1457 else
1458 driver->ttys[tty->index] = NULL;
1459}
1460
1461/*
1462 * tty_reopen() - fast re-open of an open tty
1463 * @tty - the tty to open
1464 *
1465 * Return 0 on success, -errno on error.
1466 * Re-opens on master ptys are not allowed and return -EIO.
1467 *
1468 * Locking: Caller must hold tty_lock
1469 */
1470static int tty_reopen(struct tty_struct *tty)
1471{
1472 struct tty_driver *driver = tty->driver;
1473
1474 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1475 driver->subtype == PTY_TYPE_MASTER)
1476 return -EIO;
1477
1478 if (!tty->count)
1479 return -EAGAIN;
1480
1481 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1482 return -EBUSY;
1483
1484 tty->count++;
1485
1486 if (!tty->ldisc)
1487 return tty_ldisc_reinit(tty, tty->termios.c_line);
1488
1489 return 0;
1490}
1491
1492/**
1493 * tty_init_dev - initialise a tty device
1494 * @driver: tty driver we are opening a device on
1495 * @idx: device index
1496 * @ret_tty: returned tty structure
1497 *
1498 * Prepare a tty device. This may not be a "new" clean device but
1499 * could also be an active device. The pty drivers require special
1500 * handling because of this.
1501 *
1502 * Locking:
1503 * The function is called under the tty_mutex, which
1504 * protects us from the tty struct or driver itself going away.
1505 *
1506 * On exit the tty device has the line discipline attached and
1507 * a reference count of 1. If a pair was created for pty/tty use
1508 * and the other was a pty master then it too has a reference count of 1.
1509 *
1510 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1511 * failed open. The new code protects the open with a mutex, so it's
1512 * really quite straightforward. The mutex locking can probably be
1513 * relaxed for the (most common) case of reopening a tty.
1514 */
1515
1516struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1517{
1518 struct tty_struct *tty;
1519 int retval;
1520
1521 /*
1522 * First time open is complex, especially for PTY devices.
1523 * This code guarantees that either everything succeeds and the
1524 * TTY is ready for operation, or else the table slots are vacated
1525 * and the allocated memory released. (Except that the termios
1526 * and locked termios may be retained.)
1527 */
1528
1529 if (!try_module_get(driver->owner))
1530 return ERR_PTR(-ENODEV);
1531
1532 tty = alloc_tty_struct(driver, idx);
1533 if (!tty) {
1534 retval = -ENOMEM;
1535 goto err_module_put;
1536 }
1537
1538 tty_lock(tty);
1539 retval = tty_driver_install_tty(driver, tty);
1540 if (retval < 0)
1541 goto err_free_tty;
1542
1543 if (!tty->port)
1544 tty->port = driver->ports[idx];
1545
1546 WARN_RATELIMIT(!tty->port,
1547 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1548 __func__, tty->driver->name);
1549
1550 tty->port->itty = tty;
1551
1552 /*
1553 * Structures all installed ... call the ldisc open routines.
1554 * If we fail here just call release_tty to clean up. No need
1555 * to decrement the use counts, as release_tty doesn't care.
1556 */
1557 retval = tty_ldisc_setup(tty, tty->link);
1558 if (retval)
1559 goto err_release_tty;
1560 /* Return the tty locked so that it cannot vanish under the caller */
1561 return tty;
1562
1563err_free_tty:
1564 tty_unlock(tty);
1565 free_tty_struct(tty);
1566err_module_put:
1567 module_put(driver->owner);
1568 return ERR_PTR(retval);
1569
1570 /* call the tty release_tty routine to clean out this slot */
1571err_release_tty:
1572 tty_unlock(tty);
1573 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1574 retval, idx);
1575 release_tty(tty, idx);
1576 return ERR_PTR(retval);
1577}
1578
1579static void tty_free_termios(struct tty_struct *tty)
1580{
1581 struct ktermios *tp;
1582 int idx = tty->index;
1583
1584 /* If the port is going to reset then it has no termios to save */
1585 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1586 return;
1587
1588 /* Stash the termios data */
1589 tp = tty->driver->termios[idx];
1590 if (tp == NULL) {
1591 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1592 if (tp == NULL)
1593 return;
1594 tty->driver->termios[idx] = tp;
1595 }
1596 *tp = tty->termios;
1597}
1598
1599/**
1600 * tty_flush_works - flush all works of a tty/pty pair
1601 * @tty: tty device to flush works for (or either end of a pty pair)
1602 *
1603 * Sync flush all works belonging to @tty (and the 'other' tty).
1604 */
1605static void tty_flush_works(struct tty_struct *tty)
1606{
1607 flush_work(&tty->SAK_work);
1608 flush_work(&tty->hangup_work);
1609 if (tty->link) {
1610 flush_work(&tty->link->SAK_work);
1611 flush_work(&tty->link->hangup_work);
1612 }
1613}
1614
1615/**
1616 * release_one_tty - release tty structure memory
1617 * @kref: kref of tty we are obliterating
1618 *
1619 * Releases memory associated with a tty structure, and clears out the
1620 * driver table slots. This function is called when a device is no longer
1621 * in use. It also gets called when setup of a device fails.
1622 *
1623 * Locking:
1624 * takes the file list lock internally when working on the list
1625 * of ttys that the driver keeps.
1626 *
1627 * This method gets called from a work queue so that the driver private
1628 * cleanup ops can sleep (needed for USB at least)
1629 */
1630static void release_one_tty(struct work_struct *work)
1631{
1632 struct tty_struct *tty =
1633 container_of(work, struct tty_struct, hangup_work);
1634 struct tty_driver *driver = tty->driver;
1635 struct module *owner = driver->owner;
1636
1637 if (tty->ops->cleanup)
1638 tty->ops->cleanup(tty);
1639
1640 tty->magic = 0;
1641 tty_driver_kref_put(driver);
1642 module_put(owner);
1643
1644 spin_lock(&tty->files_lock);
1645 list_del_init(&tty->tty_files);
1646 spin_unlock(&tty->files_lock);
1647
1648 put_pid(tty->pgrp);
1649 put_pid(tty->session);
1650 free_tty_struct(tty);
1651}
1652
1653static void queue_release_one_tty(struct kref *kref)
1654{
1655 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1656
1657 /* The hangup queue is now free so we can reuse it rather than
1658 waste a chunk of memory for each port */
1659 INIT_WORK(&tty->hangup_work, release_one_tty);
1660 schedule_work(&tty->hangup_work);
1661}
1662
1663/**
1664 * tty_kref_put - release a tty kref
1665 * @tty: tty device
1666 *
1667 * Release a reference to a tty device and if need be let the kref
1668 * layer destruct the object for us
1669 */
1670
1671void tty_kref_put(struct tty_struct *tty)
1672{
1673 if (tty)
1674 kref_put(&tty->kref, queue_release_one_tty);
1675}
1676EXPORT_SYMBOL(tty_kref_put);
1677
1678/**
1679 * release_tty - release tty structure memory
1680 *
1681 * Release both @tty and a possible linked partner (think pty pair),
1682 * and decrement the refcount of the backing module.
1683 *
1684 * Locking:
1685 * tty_mutex
1686 * takes the file list lock internally when working on the list
1687 * of ttys that the driver keeps.
1688 *
1689 */
1690static void release_tty(struct tty_struct *tty, int idx)
1691{
1692 /* This should always be true but check for the moment */
1693 WARN_ON(tty->index != idx);
1694 WARN_ON(!mutex_is_locked(&tty_mutex));
1695 if (tty->ops->shutdown)
1696 tty->ops->shutdown(tty);
1697 tty_free_termios(tty);
1698 tty_driver_remove_tty(tty->driver, tty);
1699 tty->port->itty = NULL;
1700 if (tty->link)
1701 tty->link->port->itty = NULL;
1702 tty_buffer_cancel_work(tty->port);
1703
1704 tty_kref_put(tty->link);
1705 tty_kref_put(tty);
1706}
1707
1708/**
1709 * tty_release_checks - check a tty before real release
1710 * @tty: tty to check
1711 * @o_tty: link of @tty (if any)
1712 * @idx: index of the tty
1713 *
1714 * Performs some paranoid checking before true release of the @tty.
1715 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1716 */
1717static int tty_release_checks(struct tty_struct *tty, int idx)
1718{
1719#ifdef TTY_PARANOIA_CHECK
1720 if (idx < 0 || idx >= tty->driver->num) {
1721 tty_debug(tty, "bad idx %d\n", idx);
1722 return -1;
1723 }
1724
1725 /* not much to check for devpts */
1726 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1727 return 0;
1728
1729 if (tty != tty->driver->ttys[idx]) {
1730 tty_debug(tty, "bad driver table[%d] = %p\n",
1731 idx, tty->driver->ttys[idx]);
1732 return -1;
1733 }
1734 if (tty->driver->other) {
1735 struct tty_struct *o_tty = tty->link;
1736
1737 if (o_tty != tty->driver->other->ttys[idx]) {
1738 tty_debug(tty, "bad other table[%d] = %p\n",
1739 idx, tty->driver->other->ttys[idx]);
1740 return -1;
1741 }
1742 if (o_tty->link != tty) {
1743 tty_debug(tty, "bad link = %p\n", o_tty->link);
1744 return -1;
1745 }
1746 }
1747#endif
1748 return 0;
1749}
1750
1751/**
1752 * tty_release - vfs callback for close
1753 * @inode: inode of tty
1754 * @filp: file pointer for handle to tty
1755 *
1756 * Called the last time each file handle is closed that references
1757 * this tty. There may however be several such references.
1758 *
1759 * Locking:
1760 * Takes bkl. See tty_release_dev
1761 *
1762 * Even releasing the tty structures is a tricky business.. We have
1763 * to be very careful that the structures are all released at the
1764 * same time, as interrupts might otherwise get the wrong pointers.
1765 *
1766 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1767 * lead to double frees or releasing memory still in use.
1768 */
1769
1770int tty_release(struct inode *inode, struct file *filp)
1771{
1772 struct tty_struct *tty = file_tty(filp);
1773 struct tty_struct *o_tty = NULL;
1774 int do_sleep, final;
1775 int idx;
1776 long timeout = 0;
1777 int once = 1;
1778
1779 if (tty_paranoia_check(tty, inode, __func__))
1780 return 0;
1781
1782 tty_lock(tty);
1783 check_tty_count(tty, __func__);
1784
1785 __tty_fasync(-1, filp, 0);
1786
1787 idx = tty->index;
1788 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1789 tty->driver->subtype == PTY_TYPE_MASTER)
1790 o_tty = tty->link;
1791
1792 if (tty_release_checks(tty, idx)) {
1793 tty_unlock(tty);
1794 return 0;
1795 }
1796
1797 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1798
1799 if (tty->ops->close)
1800 tty->ops->close(tty, filp);
1801
1802 /* If tty is pty master, lock the slave pty (stable lock order) */
1803 tty_lock_slave(o_tty);
1804
1805 /*
1806 * Sanity check: if tty->count is going to zero, there shouldn't be
1807 * any waiters on tty->read_wait or tty->write_wait. We test the
1808 * wait queues and kick everyone out _before_ actually starting to
1809 * close. This ensures that we won't block while releasing the tty
1810 * structure.
1811 *
1812 * The test for the o_tty closing is necessary, since the master and
1813 * slave sides may close in any order. If the slave side closes out
1814 * first, its count will be one, since the master side holds an open.
1815 * Thus this test wouldn't be triggered at the time the slave closed,
1816 * so we do it now.
1817 */
1818 while (1) {
1819 do_sleep = 0;
1820
1821 if (tty->count <= 1) {
1822 if (waitqueue_active(&tty->read_wait)) {
1823 wake_up_poll(&tty->read_wait, POLLIN);
1824 do_sleep++;
1825 }
1826 if (waitqueue_active(&tty->write_wait)) {
1827 wake_up_poll(&tty->write_wait, POLLOUT);
1828 do_sleep++;
1829 }
1830 }
1831 if (o_tty && o_tty->count <= 1) {
1832 if (waitqueue_active(&o_tty->read_wait)) {
1833 wake_up_poll(&o_tty->read_wait, POLLIN);
1834 do_sleep++;
1835 }
1836 if (waitqueue_active(&o_tty->write_wait)) {
1837 wake_up_poll(&o_tty->write_wait, POLLOUT);
1838 do_sleep++;
1839 }
1840 }
1841 if (!do_sleep)
1842 break;
1843
1844 if (once) {
1845 once = 0;
1846 tty_warn(tty, "read/write wait queue active!\n");
1847 }
1848 schedule_timeout_killable(timeout);
1849 if (timeout < 120 * HZ)
1850 timeout = 2 * timeout + 1;
1851 else
1852 timeout = MAX_SCHEDULE_TIMEOUT;
1853 }
1854
1855 if (o_tty) {
1856 if (--o_tty->count < 0) {
1857 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1858 o_tty->count = 0;
1859 }
1860 }
1861 if (--tty->count < 0) {
1862 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1863 tty->count = 0;
1864 }
1865
1866 /*
1867 * We've decremented tty->count, so we need to remove this file
1868 * descriptor off the tty->tty_files list; this serves two
1869 * purposes:
1870 * - check_tty_count sees the correct number of file descriptors
1871 * associated with this tty.
1872 * - do_tty_hangup no longer sees this file descriptor as
1873 * something that needs to be handled for hangups.
1874 */
1875 tty_del_file(filp);
1876
1877 /*
1878 * Perform some housekeeping before deciding whether to return.
1879 *
1880 * If _either_ side is closing, make sure there aren't any
1881 * processes that still think tty or o_tty is their controlling
1882 * tty.
1883 */
1884 if (!tty->count) {
1885 read_lock(&tasklist_lock);
1886 session_clear_tty(tty->session);
1887 if (o_tty)
1888 session_clear_tty(o_tty->session);
1889 read_unlock(&tasklist_lock);
1890 }
1891
1892 /* check whether both sides are closing ... */
1893 final = !tty->count && !(o_tty && o_tty->count);
1894
1895 tty_unlock_slave(o_tty);
1896 tty_unlock(tty);
1897
1898 /* At this point, the tty->count == 0 should ensure a dead tty
1899 cannot be re-opened by a racing opener */
1900
1901 if (!final)
1902 return 0;
1903
1904 tty_debug_hangup(tty, "final close\n");
1905 /*
1906 * Ask the line discipline code to release its structures
1907 */
1908 tty_ldisc_release(tty);
1909
1910 /* Wait for pending work before tty destruction commmences */
1911 tty_flush_works(tty);
1912
1913 tty_debug_hangup(tty, "freeing structure\n");
1914 /*
1915 * The release_tty function takes care of the details of clearing
1916 * the slots and preserving the termios structure. The tty_unlock_pair
1917 * should be safe as we keep a kref while the tty is locked (so the
1918 * unlock never unlocks a freed tty).
1919 */
1920 mutex_lock(&tty_mutex);
1921 release_tty(tty, idx);
1922 mutex_unlock(&tty_mutex);
1923
1924 return 0;
1925}
1926
1927/**
1928 * tty_open_current_tty - get locked tty of current task
1929 * @device: device number
1930 * @filp: file pointer to tty
1931 * @return: locked tty of the current task iff @device is /dev/tty
1932 *
1933 * Performs a re-open of the current task's controlling tty.
1934 *
1935 * We cannot return driver and index like for the other nodes because
1936 * devpts will not work then. It expects inodes to be from devpts FS.
1937 */
1938static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1939{
1940 struct tty_struct *tty;
1941 int retval;
1942
1943 if (device != MKDEV(TTYAUX_MAJOR, 0))
1944 return NULL;
1945
1946 tty = get_current_tty();
1947 if (!tty)
1948 return ERR_PTR(-ENXIO);
1949
1950 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1951 /* noctty = 1; */
1952 tty_lock(tty);
1953 tty_kref_put(tty); /* safe to drop the kref now */
1954
1955 retval = tty_reopen(tty);
1956 if (retval < 0) {
1957 tty_unlock(tty);
1958 tty = ERR_PTR(retval);
1959 }
1960 return tty;
1961}
1962
1963/**
1964 * tty_lookup_driver - lookup a tty driver for a given device file
1965 * @device: device number
1966 * @filp: file pointer to tty
1967 * @noctty: set if the device should not become a controlling tty
1968 * @index: index for the device in the @return driver
1969 * @return: driver for this inode (with increased refcount)
1970 *
1971 * If @return is not erroneous, the caller is responsible to decrement the
1972 * refcount by tty_driver_kref_put.
1973 *
1974 * Locking: tty_mutex protects get_tty_driver
1975 */
1976static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1977 int *index)
1978{
1979 struct tty_driver *driver;
1980
1981 switch (device) {
1982#ifdef CONFIG_VT
1983 case MKDEV(TTY_MAJOR, 0): {
1984 extern struct tty_driver *console_driver;
1985 driver = tty_driver_kref_get(console_driver);
1986 *index = fg_console;
1987 break;
1988 }
1989#endif
1990 case MKDEV(TTYAUX_MAJOR, 1): {
1991 struct tty_driver *console_driver = console_device(index);
1992 if (console_driver) {
1993 driver = tty_driver_kref_get(console_driver);
1994 if (driver) {
1995 /* Don't let /dev/console block */
1996 filp->f_flags |= O_NONBLOCK;
1997 break;
1998 }
1999 }
2000 return ERR_PTR(-ENODEV);
2001 }
2002 default:
2003 driver = get_tty_driver(device, index);
2004 if (!driver)
2005 return ERR_PTR(-ENODEV);
2006 break;
2007 }
2008 return driver;
2009}
2010
2011/**
2012 * tty_open_by_driver - open a tty device
2013 * @device: dev_t of device to open
2014 * @inode: inode of device file
2015 * @filp: file pointer to tty
2016 *
2017 * Performs the driver lookup, checks for a reopen, or otherwise
2018 * performs the first-time tty initialization.
2019 *
2020 * Returns the locked initialized or re-opened &tty_struct
2021 *
2022 * Claims the global tty_mutex to serialize:
2023 * - concurrent first-time tty initialization
2024 * - concurrent tty driver removal w/ lookup
2025 * - concurrent tty removal from driver table
2026 */
2027static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
2028 struct file *filp)
2029{
2030 struct tty_struct *tty;
2031 struct tty_driver *driver = NULL;
2032 int index = -1;
2033 int retval;
2034
2035 mutex_lock(&tty_mutex);
2036 driver = tty_lookup_driver(device, filp, &index);
2037 if (IS_ERR(driver)) {
2038 mutex_unlock(&tty_mutex);
2039 return ERR_CAST(driver);
2040 }
2041
2042 /* check whether we're reopening an existing tty */
2043 tty = tty_driver_lookup_tty(driver, filp, index);
2044 if (IS_ERR(tty)) {
2045 mutex_unlock(&tty_mutex);
2046 goto out;
2047 }
2048
2049 if (tty) {
2050 mutex_unlock(&tty_mutex);
2051 retval = tty_lock_interruptible(tty);
2052 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2053 if (retval) {
2054 if (retval == -EINTR)
2055 retval = -ERESTARTSYS;
2056 tty = ERR_PTR(retval);
2057 goto out;
2058 }
2059 retval = tty_reopen(tty);
2060 if (retval < 0) {
2061 tty_unlock(tty);
2062 tty = ERR_PTR(retval);
2063 }
2064 } else { /* Returns with the tty_lock held for now */
2065 tty = tty_init_dev(driver, index);
2066 mutex_unlock(&tty_mutex);
2067 }
2068out:
2069 tty_driver_kref_put(driver);
2070 return tty;
2071}
2072
2073/**
2074 * tty_open - open a tty device
2075 * @inode: inode of device file
2076 * @filp: file pointer to tty
2077 *
2078 * tty_open and tty_release keep up the tty count that contains the
2079 * number of opens done on a tty. We cannot use the inode-count, as
2080 * different inodes might point to the same tty.
2081 *
2082 * Open-counting is needed for pty masters, as well as for keeping
2083 * track of serial lines: DTR is dropped when the last close happens.
2084 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2085 *
2086 * The termios state of a pty is reset on first open so that
2087 * settings don't persist across reuse.
2088 *
2089 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2090 * tty->count should protect the rest.
2091 * ->siglock protects ->signal/->sighand
2092 *
2093 * Note: the tty_unlock/lock cases without a ref are only safe due to
2094 * tty_mutex
2095 */
2096
2097static int tty_open(struct inode *inode, struct file *filp)
2098{
2099 struct tty_struct *tty;
2100 int noctty, retval;
2101 dev_t device = inode->i_rdev;
2102 unsigned saved_flags = filp->f_flags;
2103
2104 nonseekable_open(inode, filp);
2105
2106retry_open:
2107 retval = tty_alloc_file(filp);
2108 if (retval)
2109 return -ENOMEM;
2110
2111 tty = tty_open_current_tty(device, filp);
2112 if (!tty)
2113 tty = tty_open_by_driver(device, inode, filp);
2114
2115 if (IS_ERR(tty)) {
2116 tty_free_file(filp);
2117 retval = PTR_ERR(tty);
2118 if (retval != -EAGAIN || signal_pending(current))
2119 return retval;
2120 schedule();
2121 goto retry_open;
2122 }
2123
2124 tty_add_file(tty, filp);
2125
2126 check_tty_count(tty, __func__);
2127 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2128
2129 if (tty->ops->open)
2130 retval = tty->ops->open(tty, filp);
2131 else
2132 retval = -ENODEV;
2133 filp->f_flags = saved_flags;
2134
2135 if (retval) {
2136 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2137
2138 tty_unlock(tty); /* need to call tty_release without BTM */
2139 tty_release(inode, filp);
2140 if (retval != -ERESTARTSYS)
2141 return retval;
2142
2143 if (signal_pending(current))
2144 return retval;
2145
2146 schedule();
2147 /*
2148 * Need to reset f_op in case a hangup happened.
2149 */
2150 if (tty_hung_up_p(filp))
2151 filp->f_op = &tty_fops;
2152 goto retry_open;
2153 }
2154 clear_bit(TTY_HUPPED, &tty->flags);
2155
2156
2157 read_lock(&tasklist_lock);
2158 spin_lock_irq(¤t->sighand->siglock);
2159 noctty = (filp->f_flags & O_NOCTTY) ||
2160 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2161 device == MKDEV(TTYAUX_MAJOR, 1) ||
2162 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2163 tty->driver->subtype == PTY_TYPE_MASTER);
2164
2165 if (!noctty &&
2166 current->signal->leader &&
2167 !current->signal->tty &&
2168 tty->session == NULL) {
2169 /*
2170 * Don't let a process that only has write access to the tty
2171 * obtain the privileges associated with having a tty as
2172 * controlling terminal (being able to reopen it with full
2173 * access through /dev/tty, being able to perform pushback).
2174 * Many distributions set the group of all ttys to "tty" and
2175 * grant write-only access to all terminals for setgid tty
2176 * binaries, which should not imply full privileges on all ttys.
2177 *
2178 * This could theoretically break old code that performs open()
2179 * on a write-only file descriptor. In that case, it might be
2180 * necessary to also permit this if
2181 * inode_permission(inode, MAY_READ) == 0.
2182 */
2183 if (filp->f_mode & FMODE_READ)
2184 __proc_set_tty(tty);
2185 }
2186 spin_unlock_irq(¤t->sighand->siglock);
2187 read_unlock(&tasklist_lock);
2188 tty_unlock(tty);
2189 return 0;
2190}
2191
2192
2193
2194/**
2195 * tty_poll - check tty status
2196 * @filp: file being polled
2197 * @wait: poll wait structures to update
2198 *
2199 * Call the line discipline polling method to obtain the poll
2200 * status of the device.
2201 *
2202 * Locking: locks called line discipline but ldisc poll method
2203 * may be re-entered freely by other callers.
2204 */
2205
2206static unsigned int tty_poll(struct file *filp, poll_table *wait)
2207{
2208 struct tty_struct *tty = file_tty(filp);
2209 struct tty_ldisc *ld;
2210 int ret = 0;
2211
2212 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2213 return 0;
2214
2215 ld = tty_ldisc_ref_wait(tty);
2216 if (!ld)
2217 return hung_up_tty_poll(filp, wait);
2218 if (ld->ops->poll)
2219 ret = ld->ops->poll(tty, filp, wait);
2220 tty_ldisc_deref(ld);
2221 return ret;
2222}
2223
2224static int __tty_fasync(int fd, struct file *filp, int on)
2225{
2226 struct tty_struct *tty = file_tty(filp);
2227 unsigned long flags;
2228 int retval = 0;
2229
2230 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2231 goto out;
2232
2233 retval = fasync_helper(fd, filp, on, &tty->fasync);
2234 if (retval <= 0)
2235 goto out;
2236
2237 if (on) {
2238 enum pid_type type;
2239 struct pid *pid;
2240
2241 spin_lock_irqsave(&tty->ctrl_lock, flags);
2242 if (tty->pgrp) {
2243 pid = tty->pgrp;
2244 type = PIDTYPE_PGID;
2245 } else {
2246 pid = task_pid(current);
2247 type = PIDTYPE_PID;
2248 }
2249 get_pid(pid);
2250 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2251 __f_setown(filp, pid, type, 0);
2252 put_pid(pid);
2253 retval = 0;
2254 }
2255out:
2256 return retval;
2257}
2258
2259static int tty_fasync(int fd, struct file *filp, int on)
2260{
2261 struct tty_struct *tty = file_tty(filp);
2262 int retval = -ENOTTY;
2263
2264 tty_lock(tty);
2265 if (!tty_hung_up_p(filp))
2266 retval = __tty_fasync(fd, filp, on);
2267 tty_unlock(tty);
2268
2269 return retval;
2270}
2271
2272/**
2273 * tiocsti - fake input character
2274 * @tty: tty to fake input into
2275 * @p: pointer to character
2276 *
2277 * Fake input to a tty device. Does the necessary locking and
2278 * input management.
2279 *
2280 * FIXME: does not honour flow control ??
2281 *
2282 * Locking:
2283 * Called functions take tty_ldiscs_lock
2284 * current->signal->tty check is safe without locks
2285 *
2286 * FIXME: may race normal receive processing
2287 */
2288
2289static int tiocsti(struct tty_struct *tty, char __user *p)
2290{
2291 char ch, mbz = 0;
2292 struct tty_ldisc *ld;
2293
2294 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2295 return -EPERM;
2296 if (get_user(ch, p))
2297 return -EFAULT;
2298 tty_audit_tiocsti(tty, ch);
2299 ld = tty_ldisc_ref_wait(tty);
2300 if (!ld)
2301 return -EIO;
2302 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2303 tty_ldisc_deref(ld);
2304 return 0;
2305}
2306
2307/**
2308 * tiocgwinsz - implement window query ioctl
2309 * @tty; tty
2310 * @arg: user buffer for result
2311 *
2312 * Copies the kernel idea of the window size into the user buffer.
2313 *
2314 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2315 * is consistent.
2316 */
2317
2318static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2319{
2320 int err;
2321
2322 mutex_lock(&tty->winsize_mutex);
2323 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2324 mutex_unlock(&tty->winsize_mutex);
2325
2326 return err ? -EFAULT: 0;
2327}
2328
2329/**
2330 * tty_do_resize - resize event
2331 * @tty: tty being resized
2332 * @rows: rows (character)
2333 * @cols: cols (character)
2334 *
2335 * Update the termios variables and send the necessary signals to
2336 * peform a terminal resize correctly
2337 */
2338
2339int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2340{
2341 struct pid *pgrp;
2342
2343 /* Lock the tty */
2344 mutex_lock(&tty->winsize_mutex);
2345 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2346 goto done;
2347
2348 /* Signal the foreground process group */
2349 pgrp = tty_get_pgrp(tty);
2350 if (pgrp)
2351 kill_pgrp(pgrp, SIGWINCH, 1);
2352 put_pid(pgrp);
2353
2354 tty->winsize = *ws;
2355done:
2356 mutex_unlock(&tty->winsize_mutex);
2357 return 0;
2358}
2359EXPORT_SYMBOL(tty_do_resize);
2360
2361/**
2362 * tiocswinsz - implement window size set ioctl
2363 * @tty; tty side of tty
2364 * @arg: user buffer for result
2365 *
2366 * Copies the user idea of the window size to the kernel. Traditionally
2367 * this is just advisory information but for the Linux console it
2368 * actually has driver level meaning and triggers a VC resize.
2369 *
2370 * Locking:
2371 * Driver dependent. The default do_resize method takes the
2372 * tty termios mutex and ctrl_lock. The console takes its own lock
2373 * then calls into the default method.
2374 */
2375
2376static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2377{
2378 struct winsize tmp_ws;
2379 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2380 return -EFAULT;
2381
2382 if (tty->ops->resize)
2383 return tty->ops->resize(tty, &tmp_ws);
2384 else
2385 return tty_do_resize(tty, &tmp_ws);
2386}
2387
2388/**
2389 * tioccons - allow admin to move logical console
2390 * @file: the file to become console
2391 *
2392 * Allow the administrator to move the redirected console device
2393 *
2394 * Locking: uses redirect_lock to guard the redirect information
2395 */
2396
2397static int tioccons(struct file *file)
2398{
2399 if (!capable(CAP_SYS_ADMIN))
2400 return -EPERM;
2401 if (file->f_op->write == redirected_tty_write) {
2402 struct file *f;
2403 spin_lock(&redirect_lock);
2404 f = redirect;
2405 redirect = NULL;
2406 spin_unlock(&redirect_lock);
2407 if (f)
2408 fput(f);
2409 return 0;
2410 }
2411 spin_lock(&redirect_lock);
2412 if (redirect) {
2413 spin_unlock(&redirect_lock);
2414 return -EBUSY;
2415 }
2416 redirect = get_file(file);
2417 spin_unlock(&redirect_lock);
2418 return 0;
2419}
2420
2421/**
2422 * fionbio - non blocking ioctl
2423 * @file: file to set blocking value
2424 * @p: user parameter
2425 *
2426 * Historical tty interfaces had a blocking control ioctl before
2427 * the generic functionality existed. This piece of history is preserved
2428 * in the expected tty API of posix OS's.
2429 *
2430 * Locking: none, the open file handle ensures it won't go away.
2431 */
2432
2433static int fionbio(struct file *file, int __user *p)
2434{
2435 int nonblock;
2436
2437 if (get_user(nonblock, p))
2438 return -EFAULT;
2439
2440 spin_lock(&file->f_lock);
2441 if (nonblock)
2442 file->f_flags |= O_NONBLOCK;
2443 else
2444 file->f_flags &= ~O_NONBLOCK;
2445 spin_unlock(&file->f_lock);
2446 return 0;
2447}
2448
2449/**
2450 * tiocsctty - set controlling tty
2451 * @tty: tty structure
2452 * @arg: user argument
2453 *
2454 * This ioctl is used to manage job control. It permits a session
2455 * leader to set this tty as the controlling tty for the session.
2456 *
2457 * Locking:
2458 * Takes tty_lock() to serialize proc_set_tty() for this tty
2459 * Takes tasklist_lock internally to walk sessions
2460 * Takes ->siglock() when updating signal->tty
2461 */
2462
2463static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2464{
2465 int ret = 0;
2466
2467 tty_lock(tty);
2468 read_lock(&tasklist_lock);
2469
2470 if (current->signal->leader && (task_session(current) == tty->session))
2471 goto unlock;
2472
2473 /*
2474 * The process must be a session leader and
2475 * not have a controlling tty already.
2476 */
2477 if (!current->signal->leader || current->signal->tty) {
2478 ret = -EPERM;
2479 goto unlock;
2480 }
2481
2482 if (tty->session) {
2483 /*
2484 * This tty is already the controlling
2485 * tty for another session group!
2486 */
2487 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2488 /*
2489 * Steal it away
2490 */
2491 session_clear_tty(tty->session);
2492 } else {
2493 ret = -EPERM;
2494 goto unlock;
2495 }
2496 }
2497
2498 /* See the comment in tty_open(). */
2499 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2500 ret = -EPERM;
2501 goto unlock;
2502 }
2503
2504 proc_set_tty(tty);
2505unlock:
2506 read_unlock(&tasklist_lock);
2507 tty_unlock(tty);
2508 return ret;
2509}
2510
2511/**
2512 * tty_get_pgrp - return a ref counted pgrp pid
2513 * @tty: tty to read
2514 *
2515 * Returns a refcounted instance of the pid struct for the process
2516 * group controlling the tty.
2517 */
2518
2519struct pid *tty_get_pgrp(struct tty_struct *tty)
2520{
2521 unsigned long flags;
2522 struct pid *pgrp;
2523
2524 spin_lock_irqsave(&tty->ctrl_lock, flags);
2525 pgrp = get_pid(tty->pgrp);
2526 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2527
2528 return pgrp;
2529}
2530EXPORT_SYMBOL_GPL(tty_get_pgrp);
2531
2532/*
2533 * This checks not only the pgrp, but falls back on the pid if no
2534 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2535 * without this...
2536 *
2537 * The caller must hold rcu lock or the tasklist lock.
2538 */
2539static struct pid *session_of_pgrp(struct pid *pgrp)
2540{
2541 struct task_struct *p;
2542 struct pid *sid = NULL;
2543
2544 p = pid_task(pgrp, PIDTYPE_PGID);
2545 if (p == NULL)
2546 p = pid_task(pgrp, PIDTYPE_PID);
2547 if (p != NULL)
2548 sid = task_session(p);
2549
2550 return sid;
2551}
2552
2553/**
2554 * tiocgpgrp - get process group
2555 * @tty: tty passed by user
2556 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2557 * @p: returned pid
2558 *
2559 * Obtain the process group of the tty. If there is no process group
2560 * return an error.
2561 *
2562 * Locking: none. Reference to current->signal->tty is safe.
2563 */
2564
2565static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2566{
2567 struct pid *pid;
2568 int ret;
2569 /*
2570 * (tty == real_tty) is a cheap way of
2571 * testing if the tty is NOT a master pty.
2572 */
2573 if (tty == real_tty && current->signal->tty != real_tty)
2574 return -ENOTTY;
2575 pid = tty_get_pgrp(real_tty);
2576 ret = put_user(pid_vnr(pid), p);
2577 put_pid(pid);
2578 return ret;
2579}
2580
2581/**
2582 * tiocspgrp - attempt to set process group
2583 * @tty: tty passed by user
2584 * @real_tty: tty side device matching tty passed by user
2585 * @p: pid pointer
2586 *
2587 * Set the process group of the tty to the session passed. Only
2588 * permitted where the tty session is our session.
2589 *
2590 * Locking: RCU, ctrl lock
2591 */
2592
2593static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2594{
2595 struct pid *pgrp;
2596 pid_t pgrp_nr;
2597 int retval = tty_check_change(real_tty);
2598
2599 if (retval == -EIO)
2600 return -ENOTTY;
2601 if (retval)
2602 return retval;
2603 if (!current->signal->tty ||
2604 (current->signal->tty != real_tty) ||
2605 (real_tty->session != task_session(current)))
2606 return -ENOTTY;
2607 if (get_user(pgrp_nr, p))
2608 return -EFAULT;
2609 if (pgrp_nr < 0)
2610 return -EINVAL;
2611 rcu_read_lock();
2612 pgrp = find_vpid(pgrp_nr);
2613 retval = -ESRCH;
2614 if (!pgrp)
2615 goto out_unlock;
2616 retval = -EPERM;
2617 if (session_of_pgrp(pgrp) != task_session(current))
2618 goto out_unlock;
2619 retval = 0;
2620 spin_lock_irq(&tty->ctrl_lock);
2621 put_pid(real_tty->pgrp);
2622 real_tty->pgrp = get_pid(pgrp);
2623 spin_unlock_irq(&tty->ctrl_lock);
2624out_unlock:
2625 rcu_read_unlock();
2626 return retval;
2627}
2628
2629/**
2630 * tiocgsid - get session id
2631 * @tty: tty passed by user
2632 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2633 * @p: pointer to returned session id
2634 *
2635 * Obtain the session id of the tty. If there is no session
2636 * return an error.
2637 *
2638 * Locking: none. Reference to current->signal->tty is safe.
2639 */
2640
2641static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2642{
2643 /*
2644 * (tty == real_tty) is a cheap way of
2645 * testing if the tty is NOT a master pty.
2646 */
2647 if (tty == real_tty && current->signal->tty != real_tty)
2648 return -ENOTTY;
2649 if (!real_tty->session)
2650 return -ENOTTY;
2651 return put_user(pid_vnr(real_tty->session), p);
2652}
2653
2654/**
2655 * tiocsetd - set line discipline
2656 * @tty: tty device
2657 * @p: pointer to user data
2658 *
2659 * Set the line discipline according to user request.
2660 *
2661 * Locking: see tty_set_ldisc, this function is just a helper
2662 */
2663
2664static int tiocsetd(struct tty_struct *tty, int __user *p)
2665{
2666 int disc;
2667 int ret;
2668
2669 if (get_user(disc, p))
2670 return -EFAULT;
2671
2672 ret = tty_set_ldisc(tty, disc);
2673
2674 return ret;
2675}
2676
2677/**
2678 * tiocgetd - get line discipline
2679 * @tty: tty device
2680 * @p: pointer to user data
2681 *
2682 * Retrieves the line discipline id directly from the ldisc.
2683 *
2684 * Locking: waits for ldisc reference (in case the line discipline
2685 * is changing or the tty is being hungup)
2686 */
2687
2688static int tiocgetd(struct tty_struct *tty, int __user *p)
2689{
2690 struct tty_ldisc *ld;
2691 int ret;
2692
2693 ld = tty_ldisc_ref_wait(tty);
2694 if (!ld)
2695 return -EIO;
2696 ret = put_user(ld->ops->num, p);
2697 tty_ldisc_deref(ld);
2698 return ret;
2699}
2700
2701/**
2702 * send_break - performed time break
2703 * @tty: device to break on
2704 * @duration: timeout in mS
2705 *
2706 * Perform a timed break on hardware that lacks its own driver level
2707 * timed break functionality.
2708 *
2709 * Locking:
2710 * atomic_write_lock serializes
2711 *
2712 */
2713
2714static int send_break(struct tty_struct *tty, unsigned int duration)
2715{
2716 int retval;
2717
2718 if (tty->ops->break_ctl == NULL)
2719 return 0;
2720
2721 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2722 retval = tty->ops->break_ctl(tty, duration);
2723 else {
2724 /* Do the work ourselves */
2725 if (tty_write_lock(tty, 0) < 0)
2726 return -EINTR;
2727 retval = tty->ops->break_ctl(tty, -1);
2728 if (retval)
2729 goto out;
2730 if (!signal_pending(current))
2731 msleep_interruptible(duration);
2732 retval = tty->ops->break_ctl(tty, 0);
2733out:
2734 tty_write_unlock(tty);
2735 if (signal_pending(current))
2736 retval = -EINTR;
2737 }
2738 return retval;
2739}
2740
2741/**
2742 * tty_tiocmget - get modem status
2743 * @tty: tty device
2744 * @file: user file pointer
2745 * @p: pointer to result
2746 *
2747 * Obtain the modem status bits from the tty driver if the feature
2748 * is supported. Return -EINVAL if it is not available.
2749 *
2750 * Locking: none (up to the driver)
2751 */
2752
2753static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2754{
2755 int retval = -EINVAL;
2756
2757 if (tty->ops->tiocmget) {
2758 retval = tty->ops->tiocmget(tty);
2759
2760 if (retval >= 0)
2761 retval = put_user(retval, p);
2762 }
2763 return retval;
2764}
2765
2766/**
2767 * tty_tiocmset - set modem status
2768 * @tty: tty device
2769 * @cmd: command - clear bits, set bits or set all
2770 * @p: pointer to desired bits
2771 *
2772 * Set the modem status bits from the tty driver if the feature
2773 * is supported. Return -EINVAL if it is not available.
2774 *
2775 * Locking: none (up to the driver)
2776 */
2777
2778static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2779 unsigned __user *p)
2780{
2781 int retval;
2782 unsigned int set, clear, val;
2783
2784 if (tty->ops->tiocmset == NULL)
2785 return -EINVAL;
2786
2787 retval = get_user(val, p);
2788 if (retval)
2789 return retval;
2790 set = clear = 0;
2791 switch (cmd) {
2792 case TIOCMBIS:
2793 set = val;
2794 break;
2795 case TIOCMBIC:
2796 clear = val;
2797 break;
2798 case TIOCMSET:
2799 set = val;
2800 clear = ~val;
2801 break;
2802 }
2803 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2804 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2805 return tty->ops->tiocmset(tty, set, clear);
2806}
2807
2808static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2809{
2810 int retval = -EINVAL;
2811 struct serial_icounter_struct icount;
2812 memset(&icount, 0, sizeof(icount));
2813 if (tty->ops->get_icount)
2814 retval = tty->ops->get_icount(tty, &icount);
2815 if (retval != 0)
2816 return retval;
2817 if (copy_to_user(arg, &icount, sizeof(icount)))
2818 return -EFAULT;
2819 return 0;
2820}
2821
2822static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2823{
2824 static DEFINE_RATELIMIT_STATE(depr_flags,
2825 DEFAULT_RATELIMIT_INTERVAL,
2826 DEFAULT_RATELIMIT_BURST);
2827 char comm[TASK_COMM_LEN];
2828 int flags;
2829
2830 if (get_user(flags, &ss->flags))
2831 return;
2832
2833 flags &= ASYNC_DEPRECATED;
2834
2835 if (flags && __ratelimit(&depr_flags))
2836 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2837 __func__, get_task_comm(comm, current), flags);
2838}
2839
2840/*
2841 * if pty, return the slave side (real_tty)
2842 * otherwise, return self
2843 */
2844static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2845{
2846 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2847 tty->driver->subtype == PTY_TYPE_MASTER)
2848 tty = tty->link;
2849 return tty;
2850}
2851
2852/*
2853 * Split this up, as gcc can choke on it otherwise..
2854 */
2855long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2856{
2857 struct tty_struct *tty = file_tty(file);
2858 struct tty_struct *real_tty;
2859 void __user *p = (void __user *)arg;
2860 int retval;
2861 struct tty_ldisc *ld;
2862
2863 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2864 return -EINVAL;
2865
2866 real_tty = tty_pair_get_tty(tty);
2867
2868 /*
2869 * Factor out some common prep work
2870 */
2871 switch (cmd) {
2872 case TIOCSETD:
2873 case TIOCSBRK:
2874 case TIOCCBRK:
2875 case TCSBRK:
2876 case TCSBRKP:
2877 retval = tty_check_change(tty);
2878 if (retval)
2879 return retval;
2880 if (cmd != TIOCCBRK) {
2881 tty_wait_until_sent(tty, 0);
2882 if (signal_pending(current))
2883 return -EINTR;
2884 }
2885 break;
2886 }
2887
2888 /*
2889 * Now do the stuff.
2890 */
2891 switch (cmd) {
2892 case TIOCSTI:
2893 return tiocsti(tty, p);
2894 case TIOCGWINSZ:
2895 return tiocgwinsz(real_tty, p);
2896 case TIOCSWINSZ:
2897 return tiocswinsz(real_tty, p);
2898 case TIOCCONS:
2899 return real_tty != tty ? -EINVAL : tioccons(file);
2900 case FIONBIO:
2901 return fionbio(file, p);
2902 case TIOCEXCL:
2903 set_bit(TTY_EXCLUSIVE, &tty->flags);
2904 return 0;
2905 case TIOCNXCL:
2906 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2907 return 0;
2908 case TIOCGEXCL:
2909 {
2910 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2911 return put_user(excl, (int __user *)p);
2912 }
2913 case TIOCNOTTY:
2914 if (current->signal->tty != tty)
2915 return -ENOTTY;
2916 no_tty();
2917 return 0;
2918 case TIOCSCTTY:
2919 return tiocsctty(real_tty, file, arg);
2920 case TIOCGPGRP:
2921 return tiocgpgrp(tty, real_tty, p);
2922 case TIOCSPGRP:
2923 return tiocspgrp(tty, real_tty, p);
2924 case TIOCGSID:
2925 return tiocgsid(tty, real_tty, p);
2926 case TIOCGETD:
2927 return tiocgetd(tty, p);
2928 case TIOCSETD:
2929 return tiocsetd(tty, p);
2930 case TIOCVHANGUP:
2931 if (!capable(CAP_SYS_ADMIN))
2932 return -EPERM;
2933 tty_vhangup(tty);
2934 return 0;
2935 case TIOCGDEV:
2936 {
2937 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2938 return put_user(ret, (unsigned int __user *)p);
2939 }
2940 /*
2941 * Break handling
2942 */
2943 case TIOCSBRK: /* Turn break on, unconditionally */
2944 if (tty->ops->break_ctl)
2945 return tty->ops->break_ctl(tty, -1);
2946 return 0;
2947 case TIOCCBRK: /* Turn break off, unconditionally */
2948 if (tty->ops->break_ctl)
2949 return tty->ops->break_ctl(tty, 0);
2950 return 0;
2951 case TCSBRK: /* SVID version: non-zero arg --> no break */
2952 /* non-zero arg means wait for all output data
2953 * to be sent (performed above) but don't send break.
2954 * This is used by the tcdrain() termios function.
2955 */
2956 if (!arg)
2957 return send_break(tty, 250);
2958 return 0;
2959 case TCSBRKP: /* support for POSIX tcsendbreak() */
2960 return send_break(tty, arg ? arg*100 : 250);
2961
2962 case TIOCMGET:
2963 return tty_tiocmget(tty, p);
2964 case TIOCMSET:
2965 case TIOCMBIC:
2966 case TIOCMBIS:
2967 return tty_tiocmset(tty, cmd, p);
2968 case TIOCGICOUNT:
2969 retval = tty_tiocgicount(tty, p);
2970 /* For the moment allow fall through to the old method */
2971 if (retval != -EINVAL)
2972 return retval;
2973 break;
2974 case TCFLSH:
2975 switch (arg) {
2976 case TCIFLUSH:
2977 case TCIOFLUSH:
2978 /* flush tty buffer and allow ldisc to process ioctl */
2979 tty_buffer_flush(tty, NULL);
2980 break;
2981 }
2982 break;
2983 case TIOCSSERIAL:
2984 tty_warn_deprecated_flags(p);
2985 break;
2986 }
2987 if (tty->ops->ioctl) {
2988 retval = tty->ops->ioctl(tty, cmd, arg);
2989 if (retval != -ENOIOCTLCMD)
2990 return retval;
2991 }
2992 ld = tty_ldisc_ref_wait(tty);
2993 if (!ld)
2994 return hung_up_tty_ioctl(file, cmd, arg);
2995 retval = -EINVAL;
2996 if (ld->ops->ioctl) {
2997 retval = ld->ops->ioctl(tty, file, cmd, arg);
2998 if (retval == -ENOIOCTLCMD)
2999 retval = -ENOTTY;
3000 }
3001 tty_ldisc_deref(ld);
3002 return retval;
3003}
3004
3005#ifdef CONFIG_COMPAT
3006static long tty_compat_ioctl(struct file *file, unsigned int cmd,
3007 unsigned long arg)
3008{
3009 struct tty_struct *tty = file_tty(file);
3010 struct tty_ldisc *ld;
3011 int retval = -ENOIOCTLCMD;
3012
3013 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3014 return -EINVAL;
3015
3016 if (tty->ops->compat_ioctl) {
3017 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3018 if (retval != -ENOIOCTLCMD)
3019 return retval;
3020 }
3021
3022 ld = tty_ldisc_ref_wait(tty);
3023 if (!ld)
3024 return hung_up_tty_compat_ioctl(file, cmd, arg);
3025 if (ld->ops->compat_ioctl)
3026 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3027 else
3028 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3029 tty_ldisc_deref(ld);
3030
3031 return retval;
3032}
3033#endif
3034
3035static int this_tty(const void *t, struct file *file, unsigned fd)
3036{
3037 if (likely(file->f_op->read != tty_read))
3038 return 0;
3039 return file_tty(file) != t ? 0 : fd + 1;
3040}
3041
3042/*
3043 * This implements the "Secure Attention Key" --- the idea is to
3044 * prevent trojan horses by killing all processes associated with this
3045 * tty when the user hits the "Secure Attention Key". Required for
3046 * super-paranoid applications --- see the Orange Book for more details.
3047 *
3048 * This code could be nicer; ideally it should send a HUP, wait a few
3049 * seconds, then send a INT, and then a KILL signal. But you then
3050 * have to coordinate with the init process, since all processes associated
3051 * with the current tty must be dead before the new getty is allowed
3052 * to spawn.
3053 *
3054 * Now, if it would be correct ;-/ The current code has a nasty hole -
3055 * it doesn't catch files in flight. We may send the descriptor to ourselves
3056 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3057 *
3058 * Nasty bug: do_SAK is being called in interrupt context. This can
3059 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3060 */
3061void __do_SAK(struct tty_struct *tty)
3062{
3063#ifdef TTY_SOFT_SAK
3064 tty_hangup(tty);
3065#else
3066 struct task_struct *g, *p;
3067 struct pid *session;
3068 int i;
3069
3070 if (!tty)
3071 return;
3072 session = tty->session;
3073
3074 tty_ldisc_flush(tty);
3075
3076 tty_driver_flush_buffer(tty);
3077
3078 read_lock(&tasklist_lock);
3079 /* Kill the entire session */
3080 do_each_pid_task(session, PIDTYPE_SID, p) {
3081 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3082 task_pid_nr(p), p->comm);
3083 send_sig(SIGKILL, p, 1);
3084 } while_each_pid_task(session, PIDTYPE_SID, p);
3085
3086 /* Now kill any processes that happen to have the tty open */
3087 do_each_thread(g, p) {
3088 if (p->signal->tty == tty) {
3089 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3090 task_pid_nr(p), p->comm);
3091 send_sig(SIGKILL, p, 1);
3092 continue;
3093 }
3094 task_lock(p);
3095 i = iterate_fd(p->files, 0, this_tty, tty);
3096 if (i != 0) {
3097 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3098 task_pid_nr(p), p->comm, i - 1);
3099 force_sig(SIGKILL, p);
3100 }
3101 task_unlock(p);
3102 } while_each_thread(g, p);
3103 read_unlock(&tasklist_lock);
3104#endif
3105}
3106
3107static void do_SAK_work(struct work_struct *work)
3108{
3109 struct tty_struct *tty =
3110 container_of(work, struct tty_struct, SAK_work);
3111 __do_SAK(tty);
3112}
3113
3114/*
3115 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3116 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3117 * the values which we write to it will be identical to the values which it
3118 * already has. --akpm
3119 */
3120void do_SAK(struct tty_struct *tty)
3121{
3122 if (!tty)
3123 return;
3124 schedule_work(&tty->SAK_work);
3125}
3126
3127EXPORT_SYMBOL(do_SAK);
3128
3129static int dev_match_devt(struct device *dev, const void *data)
3130{
3131 const dev_t *devt = data;
3132 return dev->devt == *devt;
3133}
3134
3135/* Must put_device() after it's unused! */
3136static struct device *tty_get_device(struct tty_struct *tty)
3137{
3138 dev_t devt = tty_devnum(tty);
3139 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3140}
3141
3142
3143/**
3144 * alloc_tty_struct
3145 *
3146 * This subroutine allocates and initializes a tty structure.
3147 *
3148 * Locking: none - tty in question is not exposed at this point
3149 */
3150
3151struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3152{
3153 struct tty_struct *tty;
3154
3155 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3156 if (!tty)
3157 return NULL;
3158
3159 kref_init(&tty->kref);
3160 tty->magic = TTY_MAGIC;
3161 tty_ldisc_init(tty);
3162 tty->session = NULL;
3163 tty->pgrp = NULL;
3164 mutex_init(&tty->legacy_mutex);
3165 mutex_init(&tty->throttle_mutex);
3166 init_rwsem(&tty->termios_rwsem);
3167 mutex_init(&tty->winsize_mutex);
3168 init_ldsem(&tty->ldisc_sem);
3169 init_waitqueue_head(&tty->write_wait);
3170 init_waitqueue_head(&tty->read_wait);
3171 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3172 mutex_init(&tty->atomic_write_lock);
3173 spin_lock_init(&tty->ctrl_lock);
3174 spin_lock_init(&tty->flow_lock);
3175 spin_lock_init(&tty->files_lock);
3176 INIT_LIST_HEAD(&tty->tty_files);
3177 INIT_WORK(&tty->SAK_work, do_SAK_work);
3178
3179 tty->driver = driver;
3180 tty->ops = driver->ops;
3181 tty->index = idx;
3182 tty_line_name(driver, idx, tty->name);
3183 tty->dev = tty_get_device(tty);
3184
3185 return tty;
3186}
3187
3188/**
3189 * tty_put_char - write one character to a tty
3190 * @tty: tty
3191 * @ch: character
3192 *
3193 * Write one byte to the tty using the provided put_char method
3194 * if present. Returns the number of characters successfully output.
3195 *
3196 * Note: the specific put_char operation in the driver layer may go
3197 * away soon. Don't call it directly, use this method
3198 */
3199
3200int tty_put_char(struct tty_struct *tty, unsigned char ch)
3201{
3202 if (tty->ops->put_char)
3203 return tty->ops->put_char(tty, ch);
3204 return tty->ops->write(tty, &ch, 1);
3205}
3206EXPORT_SYMBOL_GPL(tty_put_char);
3207
3208struct class *tty_class;
3209
3210static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3211 unsigned int index, unsigned int count)
3212{
3213 int err;
3214
3215 /* init here, since reused cdevs cause crashes */
3216 driver->cdevs[index] = cdev_alloc();
3217 if (!driver->cdevs[index])
3218 return -ENOMEM;
3219 driver->cdevs[index]->ops = &tty_fops;
3220 driver->cdevs[index]->owner = driver->owner;
3221 err = cdev_add(driver->cdevs[index], dev, count);
3222 if (err)
3223 kobject_put(&driver->cdevs[index]->kobj);
3224 return err;
3225}
3226
3227/**
3228 * tty_register_device - register a tty device
3229 * @driver: the tty driver that describes the tty device
3230 * @index: the index in the tty driver for this tty device
3231 * @device: a struct device that is associated with this tty device.
3232 * This field is optional, if there is no known struct device
3233 * for this tty device it can be set to NULL safely.
3234 *
3235 * Returns a pointer to the struct device for this tty device
3236 * (or ERR_PTR(-EFOO) on error).
3237 *
3238 * This call is required to be made to register an individual tty device
3239 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3240 * that bit is not set, this function should not be called by a tty
3241 * driver.
3242 *
3243 * Locking: ??
3244 */
3245
3246struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3247 struct device *device)
3248{
3249 return tty_register_device_attr(driver, index, device, NULL, NULL);
3250}
3251EXPORT_SYMBOL(tty_register_device);
3252
3253static void tty_device_create_release(struct device *dev)
3254{
3255 dev_dbg(dev, "releasing...\n");
3256 kfree(dev);
3257}
3258
3259/**
3260 * tty_register_device_attr - register a tty device
3261 * @driver: the tty driver that describes the tty device
3262 * @index: the index in the tty driver for this tty device
3263 * @device: a struct device that is associated with this tty device.
3264 * This field is optional, if there is no known struct device
3265 * for this tty device it can be set to NULL safely.
3266 * @drvdata: Driver data to be set to device.
3267 * @attr_grp: Attribute group to be set on device.
3268 *
3269 * Returns a pointer to the struct device for this tty device
3270 * (or ERR_PTR(-EFOO) on error).
3271 *
3272 * This call is required to be made to register an individual tty device
3273 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3274 * that bit is not set, this function should not be called by a tty
3275 * driver.
3276 *
3277 * Locking: ??
3278 */
3279struct device *tty_register_device_attr(struct tty_driver *driver,
3280 unsigned index, struct device *device,
3281 void *drvdata,
3282 const struct attribute_group **attr_grp)
3283{
3284 char name[64];
3285 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3286 struct device *dev = NULL;
3287 int retval = -ENODEV;
3288 bool cdev = false;
3289
3290 if (index >= driver->num) {
3291 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3292 driver->name, index);
3293 return ERR_PTR(-EINVAL);
3294 }
3295
3296 if (driver->type == TTY_DRIVER_TYPE_PTY)
3297 pty_line_name(driver, index, name);
3298 else
3299 tty_line_name(driver, index, name);
3300
3301 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3302 retval = tty_cdev_add(driver, devt, index, 1);
3303 if (retval)
3304 goto error;
3305 cdev = true;
3306 }
3307
3308 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3309 if (!dev) {
3310 retval = -ENOMEM;
3311 goto error;
3312 }
3313
3314 dev->devt = devt;
3315 dev->class = tty_class;
3316 dev->parent = device;
3317 dev->release = tty_device_create_release;
3318 dev_set_name(dev, "%s", name);
3319 dev->groups = attr_grp;
3320 dev_set_drvdata(dev, drvdata);
3321
3322 retval = device_register(dev);
3323 if (retval)
3324 goto error;
3325
3326 return dev;
3327
3328error:
3329 put_device(dev);
3330 if (cdev) {
3331 cdev_del(driver->cdevs[index]);
3332 driver->cdevs[index] = NULL;
3333 }
3334 return ERR_PTR(retval);
3335}
3336EXPORT_SYMBOL_GPL(tty_register_device_attr);
3337
3338/**
3339 * tty_unregister_device - unregister a tty device
3340 * @driver: the tty driver that describes the tty device
3341 * @index: the index in the tty driver for this tty device
3342 *
3343 * If a tty device is registered with a call to tty_register_device() then
3344 * this function must be called when the tty device is gone.
3345 *
3346 * Locking: ??
3347 */
3348
3349void tty_unregister_device(struct tty_driver *driver, unsigned index)
3350{
3351 device_destroy(tty_class,
3352 MKDEV(driver->major, driver->minor_start) + index);
3353 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3354 cdev_del(driver->cdevs[index]);
3355 driver->cdevs[index] = NULL;
3356 }
3357}
3358EXPORT_SYMBOL(tty_unregister_device);
3359
3360/**
3361 * __tty_alloc_driver -- allocate tty driver
3362 * @lines: count of lines this driver can handle at most
3363 * @owner: module which is repsonsible for this driver
3364 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3365 *
3366 * This should not be called directly, some of the provided macros should be
3367 * used instead. Use IS_ERR and friends on @retval.
3368 */
3369struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3370 unsigned long flags)
3371{
3372 struct tty_driver *driver;
3373 unsigned int cdevs = 1;
3374 int err;
3375
3376 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3377 return ERR_PTR(-EINVAL);
3378
3379 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3380 if (!driver)
3381 return ERR_PTR(-ENOMEM);
3382
3383 kref_init(&driver->kref);
3384 driver->magic = TTY_DRIVER_MAGIC;
3385 driver->num = lines;
3386 driver->owner = owner;
3387 driver->flags = flags;
3388
3389 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3390 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3391 GFP_KERNEL);
3392 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3393 GFP_KERNEL);
3394 if (!driver->ttys || !driver->termios) {
3395 err = -ENOMEM;
3396 goto err_free_all;
3397 }
3398 }
3399
3400 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3401 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3402 GFP_KERNEL);
3403 if (!driver->ports) {
3404 err = -ENOMEM;
3405 goto err_free_all;
3406 }
3407 cdevs = lines;
3408 }
3409
3410 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3411 if (!driver->cdevs) {
3412 err = -ENOMEM;
3413 goto err_free_all;
3414 }
3415
3416 return driver;
3417err_free_all:
3418 kfree(driver->ports);
3419 kfree(driver->ttys);
3420 kfree(driver->termios);
3421 kfree(driver->cdevs);
3422 kfree(driver);
3423 return ERR_PTR(err);
3424}
3425EXPORT_SYMBOL(__tty_alloc_driver);
3426
3427static void destruct_tty_driver(struct kref *kref)
3428{
3429 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3430 int i;
3431 struct ktermios *tp;
3432
3433 if (driver->flags & TTY_DRIVER_INSTALLED) {
3434 /*
3435 * Free the termios and termios_locked structures because
3436 * we don't want to get memory leaks when modular tty
3437 * drivers are removed from the kernel.
3438 */
3439 for (i = 0; i < driver->num; i++) {
3440 tp = driver->termios[i];
3441 if (tp) {
3442 driver->termios[i] = NULL;
3443 kfree(tp);
3444 }
3445 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3446 tty_unregister_device(driver, i);
3447 }
3448 proc_tty_unregister_driver(driver);
3449 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3450 cdev_del(driver->cdevs[0]);
3451 }
3452 kfree(driver->cdevs);
3453 kfree(driver->ports);
3454 kfree(driver->termios);
3455 kfree(driver->ttys);
3456 kfree(driver);
3457}
3458
3459void tty_driver_kref_put(struct tty_driver *driver)
3460{
3461 kref_put(&driver->kref, destruct_tty_driver);
3462}
3463EXPORT_SYMBOL(tty_driver_kref_put);
3464
3465void tty_set_operations(struct tty_driver *driver,
3466 const struct tty_operations *op)
3467{
3468 driver->ops = op;
3469};
3470EXPORT_SYMBOL(tty_set_operations);
3471
3472void put_tty_driver(struct tty_driver *d)
3473{
3474 tty_driver_kref_put(d);
3475}
3476EXPORT_SYMBOL(put_tty_driver);
3477
3478/*
3479 * Called by a tty driver to register itself.
3480 */
3481int tty_register_driver(struct tty_driver *driver)
3482{
3483 int error;
3484 int i;
3485 dev_t dev;
3486 struct device *d;
3487
3488 if (!driver->major) {
3489 error = alloc_chrdev_region(&dev, driver->minor_start,
3490 driver->num, driver->name);
3491 if (!error) {
3492 driver->major = MAJOR(dev);
3493 driver->minor_start = MINOR(dev);
3494 }
3495 } else {
3496 dev = MKDEV(driver->major, driver->minor_start);
3497 error = register_chrdev_region(dev, driver->num, driver->name);
3498 }
3499 if (error < 0)
3500 goto err;
3501
3502 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3503 error = tty_cdev_add(driver, dev, 0, driver->num);
3504 if (error)
3505 goto err_unreg_char;
3506 }
3507
3508 mutex_lock(&tty_mutex);
3509 list_add(&driver->tty_drivers, &tty_drivers);
3510 mutex_unlock(&tty_mutex);
3511
3512 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3513 for (i = 0; i < driver->num; i++) {
3514 d = tty_register_device(driver, i, NULL);
3515 if (IS_ERR(d)) {
3516 error = PTR_ERR(d);
3517 goto err_unreg_devs;
3518 }
3519 }
3520 }
3521 proc_tty_register_driver(driver);
3522 driver->flags |= TTY_DRIVER_INSTALLED;
3523 return 0;
3524
3525err_unreg_devs:
3526 for (i--; i >= 0; i--)
3527 tty_unregister_device(driver, i);
3528
3529 mutex_lock(&tty_mutex);
3530 list_del(&driver->tty_drivers);
3531 mutex_unlock(&tty_mutex);
3532
3533err_unreg_char:
3534 unregister_chrdev_region(dev, driver->num);
3535err:
3536 return error;
3537}
3538EXPORT_SYMBOL(tty_register_driver);
3539
3540/*
3541 * Called by a tty driver to unregister itself.
3542 */
3543int tty_unregister_driver(struct tty_driver *driver)
3544{
3545#if 0
3546 /* FIXME */
3547 if (driver->refcount)
3548 return -EBUSY;
3549#endif
3550 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3551 driver->num);
3552 mutex_lock(&tty_mutex);
3553 list_del(&driver->tty_drivers);
3554 mutex_unlock(&tty_mutex);
3555 return 0;
3556}
3557
3558EXPORT_SYMBOL(tty_unregister_driver);
3559
3560dev_t tty_devnum(struct tty_struct *tty)
3561{
3562 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3563}
3564EXPORT_SYMBOL(tty_devnum);
3565
3566void tty_default_fops(struct file_operations *fops)
3567{
3568 *fops = tty_fops;
3569}
3570
3571/*
3572 * Initialize the console device. This is called *early*, so
3573 * we can't necessarily depend on lots of kernel help here.
3574 * Just do some early initializations, and do the complex setup
3575 * later.
3576 */
3577void __init console_init(void)
3578{
3579 initcall_t *call;
3580
3581 /* Setup the default TTY line discipline. */
3582 n_tty_init();
3583
3584 /*
3585 * set up the console device so that later boot sequences can
3586 * inform about problems etc..
3587 */
3588 call = __con_initcall_start;
3589 while (call < __con_initcall_end) {
3590 (*call)();
3591 call++;
3592 }
3593}
3594
3595static char *tty_devnode(struct device *dev, umode_t *mode)
3596{
3597 if (!mode)
3598 return NULL;
3599 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3600 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3601 *mode = 0666;
3602 return NULL;
3603}
3604
3605static int __init tty_class_init(void)
3606{
3607 tty_class = class_create(THIS_MODULE, "tty");
3608 if (IS_ERR(tty_class))
3609 return PTR_ERR(tty_class);
3610 tty_class->devnode = tty_devnode;
3611 return 0;
3612}
3613
3614postcore_initcall(tty_class_init);
3615
3616/* 3/2004 jmc: why do these devices exist? */
3617static struct cdev tty_cdev, console_cdev;
3618
3619static ssize_t show_cons_active(struct device *dev,
3620 struct device_attribute *attr, char *buf)
3621{
3622 struct console *cs[16];
3623 int i = 0;
3624 struct console *c;
3625 ssize_t count = 0;
3626
3627 console_lock();
3628 for_each_console(c) {
3629 if (!c->device)
3630 continue;
3631 if (!c->write)
3632 continue;
3633 if ((c->flags & CON_ENABLED) == 0)
3634 continue;
3635 cs[i++] = c;
3636 if (i >= ARRAY_SIZE(cs))
3637 break;
3638 }
3639 while (i--) {
3640 int index = cs[i]->index;
3641 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3642
3643 /* don't resolve tty0 as some programs depend on it */
3644 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3645 count += tty_line_name(drv, index, buf + count);
3646 else
3647 count += sprintf(buf + count, "%s%d",
3648 cs[i]->name, cs[i]->index);
3649
3650 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3651 }
3652 console_unlock();
3653
3654 return count;
3655}
3656static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3657
3658static struct attribute *cons_dev_attrs[] = {
3659 &dev_attr_active.attr,
3660 NULL
3661};
3662
3663ATTRIBUTE_GROUPS(cons_dev);
3664
3665static struct device *consdev;
3666
3667void console_sysfs_notify(void)
3668{
3669 if (consdev)
3670 sysfs_notify(&consdev->kobj, NULL, "active");
3671}
3672
3673/*
3674 * Ok, now we can initialize the rest of the tty devices and can count
3675 * on memory allocations, interrupts etc..
3676 */
3677int __init tty_init(void)
3678{
3679 cdev_init(&tty_cdev, &tty_fops);
3680 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3681 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3682 panic("Couldn't register /dev/tty driver\n");
3683 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3684
3685 cdev_init(&console_cdev, &console_fops);
3686 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3687 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3688 panic("Couldn't register /dev/console driver\n");
3689 consdev = device_create_with_groups(tty_class, NULL,
3690 MKDEV(TTYAUX_MAJOR, 1), NULL,
3691 cons_dev_groups, "console");
3692 if (IS_ERR(consdev))
3693 consdev = NULL;
3694
3695#ifdef CONFIG_VT
3696 vty_init(&console_fops);
3697#endif
3698 return 0;
3699}
3700