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