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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 */
5
6/*
7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
8 * or rs-channels. It also implements echoing, cooked mode etc.
9 *
10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 *
12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
13 * tty_struct and tty_queue structures. Previously there was an array
14 * of 256 tty_struct's which was statically allocated, and the
15 * tty_queue structures were allocated at boot time. Both are now
16 * dynamically allocated only when the tty is open.
17 *
18 * Also restructured routines so that there is more of a separation
19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
20 * the low-level tty routines (serial.c, pty.c, console.c). This
21 * makes for cleaner and more compact code. -TYT, 9/17/92
22 *
23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
24 * which can be dynamically activated and de-activated by the line
25 * discipline handling modules (like SLIP).
26 *
27 * NOTE: pay no attention to the line discipline code (yet); its
28 * interface is still subject to change in this version...
29 * -- TYT, 1/31/92
30 *
31 * Added functionality to the OPOST tty handling. No delays, but all
32 * other bits should be there.
33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 *
35 * Rewrote canonical mode and added more termios flags.
36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 *
38 * Reorganized FASYNC support so mouse code can share it.
39 * -- ctm@ardi.com, 9Sep95
40 *
41 * New TIOCLINUX variants added.
42 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 *
44 * Restrict vt switching via ioctl()
45 * -- grif@cs.ucr.edu, 5-Dec-95
46 *
47 * Move console and virtual terminal code to more appropriate files,
48 * implement CONFIG_VT and generalize console device interface.
49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 *
51 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
52 * -- Bill Hawes <whawes@star.net>, June 97
53 *
54 * Added devfs support.
55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 *
57 * Added support for a Unix98-style ptmx device.
58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 *
60 * Reduced memory usage for older ARM systems
61 * -- Russell King <rmk@arm.linux.org.uk>
62 *
63 * Move do_SAK() into process context. Less stack use in devfs functions.
64 * alloc_tty_struct() always uses kmalloc()
65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
66 */
67
68#include <linux/types.h>
69#include <linux/major.h>
70#include <linux/errno.h>
71#include <linux/signal.h>
72#include <linux/fcntl.h>
73#include <linux/sched/signal.h>
74#include <linux/sched/task.h>
75#include <linux/interrupt.h>
76#include <linux/tty.h>
77#include <linux/tty_driver.h>
78#include <linux/tty_flip.h>
79#include <linux/devpts_fs.h>
80#include <linux/file.h>
81#include <linux/fdtable.h>
82#include <linux/console.h>
83#include <linux/timer.h>
84#include <linux/ctype.h>
85#include <linux/kd.h>
86#include <linux/mm.h>
87#include <linux/string.h>
88#include <linux/slab.h>
89#include <linux/poll.h>
90#include <linux/ppp-ioctl.h>
91#include <linux/proc_fs.h>
92#include <linux/init.h>
93#include <linux/module.h>
94#include <linux/device.h>
95#include <linux/wait.h>
96#include <linux/bitops.h>
97#include <linux/delay.h>
98#include <linux/seq_file.h>
99#include <linux/serial.h>
100#include <linux/ratelimit.h>
101#include <linux/compat.h>
102#include <linux/uaccess.h>
103#include <linux/termios_internal.h>
104
105#include <linux/kbd_kern.h>
106#include <linux/vt_kern.h>
107#include <linux/selection.h>
108
109#include <linux/kmod.h>
110#include <linux/nsproxy.h>
111#include "tty.h"
112
113#undef TTY_DEBUG_HANGUP
114#ifdef TTY_DEBUG_HANGUP
115# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
116#else
117# define tty_debug_hangup(tty, f, args...) do { } while (0)
118#endif
119
120#define TTY_PARANOIA_CHECK 1
121#define CHECK_TTY_COUNT 1
122
123struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
124 .c_iflag = ICRNL | IXON,
125 .c_oflag = OPOST | ONLCR,
126 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
127 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
128 ECHOCTL | ECHOKE | IEXTEN,
129 .c_cc = INIT_C_CC,
130 .c_ispeed = 38400,
131 .c_ospeed = 38400,
132 /* .c_line = N_TTY, */
133};
134EXPORT_SYMBOL(tty_std_termios);
135
136/* This list gets poked at by procfs and various bits of boot up code. This
137 * could do with some rationalisation such as pulling the tty proc function
138 * into this file.
139 */
140
141LIST_HEAD(tty_drivers); /* linked list of tty drivers */
142
143/* Mutex to protect creating and releasing a tty */
144DEFINE_MUTEX(tty_mutex);
145
146static ssize_t tty_read(struct kiocb *, struct iov_iter *);
147static ssize_t tty_write(struct kiocb *, struct iov_iter *);
148static __poll_t tty_poll(struct file *, poll_table *);
149static int tty_open(struct inode *, struct file *);
150#ifdef CONFIG_COMPAT
151static long tty_compat_ioctl(struct file *file, unsigned int cmd,
152 unsigned long arg);
153#else
154#define tty_compat_ioctl NULL
155#endif
156static int __tty_fasync(int fd, struct file *filp, int on);
157static int tty_fasync(int fd, struct file *filp, int on);
158static void release_tty(struct tty_struct *tty, int idx);
159
160/**
161 * free_tty_struct - free a disused tty
162 * @tty: tty struct to free
163 *
164 * Free the write buffers, tty queue and tty memory itself.
165 *
166 * Locking: none. Must be called after tty is definitely unused
167 */
168static void free_tty_struct(struct tty_struct *tty)
169{
170 tty_ldisc_deinit(tty);
171 put_device(tty->dev);
172 kvfree(tty->write_buf);
173 kfree(tty);
174}
175
176static inline struct tty_struct *file_tty(struct file *file)
177{
178 return ((struct tty_file_private *)file->private_data)->tty;
179}
180
181int tty_alloc_file(struct file *file)
182{
183 struct tty_file_private *priv;
184
185 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
186 if (!priv)
187 return -ENOMEM;
188
189 file->private_data = priv;
190
191 return 0;
192}
193
194/* Associate a new file with the tty structure */
195void tty_add_file(struct tty_struct *tty, struct file *file)
196{
197 struct tty_file_private *priv = file->private_data;
198
199 priv->tty = tty;
200 priv->file = file;
201
202 spin_lock(&tty->files_lock);
203 list_add(&priv->list, &tty->tty_files);
204 spin_unlock(&tty->files_lock);
205}
206
207/**
208 * tty_free_file - free file->private_data
209 * @file: to free private_data of
210 *
211 * This shall be used only for fail path handling when tty_add_file was not
212 * called yet.
213 */
214void tty_free_file(struct file *file)
215{
216 struct tty_file_private *priv = file->private_data;
217
218 file->private_data = NULL;
219 kfree(priv);
220}
221
222/* Delete file from its tty */
223static void tty_del_file(struct file *file)
224{
225 struct tty_file_private *priv = file->private_data;
226 struct tty_struct *tty = priv->tty;
227
228 spin_lock(&tty->files_lock);
229 list_del(&priv->list);
230 spin_unlock(&tty->files_lock);
231 tty_free_file(file);
232}
233
234/**
235 * tty_name - return tty naming
236 * @tty: tty structure
237 *
238 * Convert a tty structure into a name. The name reflects the kernel naming
239 * policy and if udev is in use may not reflect user space
240 *
241 * Locking: none
242 */
243const char *tty_name(const struct tty_struct *tty)
244{
245 if (!tty) /* Hmm. NULL pointer. That's fun. */
246 return "NULL tty";
247 return tty->name;
248}
249EXPORT_SYMBOL(tty_name);
250
251const char *tty_driver_name(const struct tty_struct *tty)
252{
253 if (!tty || !tty->driver)
254 return "";
255 return tty->driver->name;
256}
257
258static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
259 const char *routine)
260{
261#ifdef TTY_PARANOIA_CHECK
262 if (!tty) {
263 pr_warn("(%d:%d): %s: NULL tty\n",
264 imajor(inode), iminor(inode), routine);
265 return 1;
266 }
267#endif
268 return 0;
269}
270
271/* Caller must hold tty_lock */
272static int check_tty_count(struct tty_struct *tty, const char *routine)
273{
274#ifdef CHECK_TTY_COUNT
275 struct list_head *p;
276 int count = 0, kopen_count = 0;
277
278 spin_lock(&tty->files_lock);
279 list_for_each(p, &tty->tty_files) {
280 count++;
281 }
282 spin_unlock(&tty->files_lock);
283 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
284 tty->driver->subtype == PTY_TYPE_SLAVE &&
285 tty->link && tty->link->count)
286 count++;
287 if (tty_port_kopened(tty->port))
288 kopen_count++;
289 if (tty->count != (count + kopen_count)) {
290 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
291 routine, tty->count, count, kopen_count);
292 return (count + kopen_count);
293 }
294#endif
295 return 0;
296}
297
298/**
299 * get_tty_driver - find device of a tty
300 * @device: device identifier
301 * @index: returns the index of the tty
302 *
303 * This routine returns a tty driver structure, given a device number and also
304 * passes back the index number.
305 *
306 * Locking: caller must hold tty_mutex
307 */
308static struct tty_driver *get_tty_driver(dev_t device, int *index)
309{
310 struct tty_driver *p;
311
312 list_for_each_entry(p, &tty_drivers, tty_drivers) {
313 dev_t base = MKDEV(p->major, p->minor_start);
314
315 if (device < base || device >= base + p->num)
316 continue;
317 *index = device - base;
318 return tty_driver_kref_get(p);
319 }
320 return NULL;
321}
322
323/**
324 * tty_dev_name_to_number - return dev_t for device name
325 * @name: user space name of device under /dev
326 * @number: pointer to dev_t that this function will populate
327 *
328 * This function converts device names like ttyS0 or ttyUSB1 into dev_t like
329 * (4, 64) or (188, 1). If no corresponding driver is registered then the
330 * function returns -%ENODEV.
331 *
332 * Locking: this acquires tty_mutex to protect the tty_drivers list from
333 * being modified while we are traversing it, and makes sure to
334 * release it before exiting.
335 */
336int tty_dev_name_to_number(const char *name, dev_t *number)
337{
338 struct tty_driver *p;
339 int ret;
340 int index, prefix_length = 0;
341 const char *str;
342
343 for (str = name; *str && !isdigit(*str); str++)
344 ;
345
346 if (!*str)
347 return -EINVAL;
348
349 ret = kstrtoint(str, 10, &index);
350 if (ret)
351 return ret;
352
353 prefix_length = str - name;
354 mutex_lock(&tty_mutex);
355
356 list_for_each_entry(p, &tty_drivers, tty_drivers)
357 if (prefix_length == strlen(p->name) && strncmp(name,
358 p->name, prefix_length) == 0) {
359 if (index < p->num) {
360 *number = MKDEV(p->major, p->minor_start + index);
361 goto out;
362 }
363 }
364
365 /* if here then driver wasn't found */
366 ret = -ENODEV;
367out:
368 mutex_unlock(&tty_mutex);
369 return ret;
370}
371EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
372
373#ifdef CONFIG_CONSOLE_POLL
374
375/**
376 * tty_find_polling_driver - find device of a polled tty
377 * @name: name string to match
378 * @line: pointer to resulting tty line nr
379 *
380 * This routine returns a tty driver structure, given a name and the condition
381 * that the tty driver is capable of polled operation.
382 */
383struct tty_driver *tty_find_polling_driver(char *name, int *line)
384{
385 struct tty_driver *p, *res = NULL;
386 int tty_line = 0;
387 int len;
388 char *str, *stp;
389
390 for (str = name; *str; str++)
391 if ((*str >= '0' && *str <= '9') || *str == ',')
392 break;
393 if (!*str)
394 return NULL;
395
396 len = str - name;
397 tty_line = simple_strtoul(str, &str, 10);
398
399 mutex_lock(&tty_mutex);
400 /* Search through the tty devices to look for a match */
401 list_for_each_entry(p, &tty_drivers, tty_drivers) {
402 if (!len || strncmp(name, p->name, len) != 0)
403 continue;
404 stp = str;
405 if (*stp == ',')
406 stp++;
407 if (*stp == '\0')
408 stp = NULL;
409
410 if (tty_line >= 0 && tty_line < p->num && p->ops &&
411 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
412 res = tty_driver_kref_get(p);
413 *line = tty_line;
414 break;
415 }
416 }
417 mutex_unlock(&tty_mutex);
418
419 return res;
420}
421EXPORT_SYMBOL_GPL(tty_find_polling_driver);
422#endif
423
424static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to)
425{
426 return 0;
427}
428
429static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
430{
431 return -EIO;
432}
433
434/* No kernel lock held - none needed ;) */
435static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
436{
437 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
438}
439
440static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
441 unsigned long arg)
442{
443 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
444}
445
446static long hung_up_tty_compat_ioctl(struct file *file,
447 unsigned int cmd, unsigned long arg)
448{
449 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
450}
451
452static int hung_up_tty_fasync(int fd, struct file *file, int on)
453{
454 return -ENOTTY;
455}
456
457static void tty_show_fdinfo(struct seq_file *m, struct file *file)
458{
459 struct tty_struct *tty = file_tty(file);
460
461 if (tty && tty->ops && tty->ops->show_fdinfo)
462 tty->ops->show_fdinfo(tty, m);
463}
464
465static const struct file_operations tty_fops = {
466 .llseek = no_llseek,
467 .read_iter = tty_read,
468 .write_iter = tty_write,
469 .splice_read = generic_file_splice_read,
470 .splice_write = iter_file_splice_write,
471 .poll = tty_poll,
472 .unlocked_ioctl = tty_ioctl,
473 .compat_ioctl = tty_compat_ioctl,
474 .open = tty_open,
475 .release = tty_release,
476 .fasync = tty_fasync,
477 .show_fdinfo = tty_show_fdinfo,
478};
479
480static const struct file_operations console_fops = {
481 .llseek = no_llseek,
482 .read_iter = tty_read,
483 .write_iter = redirected_tty_write,
484 .splice_read = generic_file_splice_read,
485 .splice_write = iter_file_splice_write,
486 .poll = tty_poll,
487 .unlocked_ioctl = tty_ioctl,
488 .compat_ioctl = tty_compat_ioctl,
489 .open = tty_open,
490 .release = tty_release,
491 .fasync = tty_fasync,
492};
493
494static const struct file_operations hung_up_tty_fops = {
495 .llseek = no_llseek,
496 .read_iter = hung_up_tty_read,
497 .write_iter = hung_up_tty_write,
498 .poll = hung_up_tty_poll,
499 .unlocked_ioctl = hung_up_tty_ioctl,
500 .compat_ioctl = hung_up_tty_compat_ioctl,
501 .release = tty_release,
502 .fasync = hung_up_tty_fasync,
503};
504
505static DEFINE_SPINLOCK(redirect_lock);
506static struct file *redirect;
507
508/**
509 * tty_wakeup - request more data
510 * @tty: terminal
511 *
512 * Internal and external helper for wakeups of tty. This function informs the
513 * line discipline if present that the driver is ready to receive more output
514 * data.
515 */
516void tty_wakeup(struct tty_struct *tty)
517{
518 struct tty_ldisc *ld;
519
520 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
521 ld = tty_ldisc_ref(tty);
522 if (ld) {
523 if (ld->ops->write_wakeup)
524 ld->ops->write_wakeup(tty);
525 tty_ldisc_deref(ld);
526 }
527 }
528 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
529}
530EXPORT_SYMBOL_GPL(tty_wakeup);
531
532/**
533 * tty_release_redirect - Release a redirect on a pty if present
534 * @tty: tty device
535 *
536 * This is available to the pty code so if the master closes, if the slave is a
537 * redirect it can release the redirect.
538 */
539static struct file *tty_release_redirect(struct tty_struct *tty)
540{
541 struct file *f = NULL;
542
543 spin_lock(&redirect_lock);
544 if (redirect && file_tty(redirect) == tty) {
545 f = redirect;
546 redirect = NULL;
547 }
548 spin_unlock(&redirect_lock);
549
550 return f;
551}
552
553/**
554 * __tty_hangup - actual handler for hangup events
555 * @tty: tty device
556 * @exit_session: if non-zero, signal all foreground group processes
557 *
558 * This can be called by a "kworker" kernel thread. That is process synchronous
559 * but doesn't hold any locks, so we need to make sure we have the appropriate
560 * locks for what we're doing.
561 *
562 * The hangup event clears any pending redirections onto the hung up device. It
563 * ensures future writes will error and it does the needed line discipline
564 * hangup and signal delivery. The tty object itself remains intact.
565 *
566 * Locking:
567 * * BTM
568 *
569 * * redirect lock for undoing redirection
570 * * file list lock for manipulating list of ttys
571 * * tty_ldiscs_lock from called functions
572 * * termios_rwsem resetting termios data
573 * * tasklist_lock to walk task list for hangup event
574 *
575 * * ->siglock to protect ->signal/->sighand
576 *
577 */
578static void __tty_hangup(struct tty_struct *tty, int exit_session)
579{
580 struct file *cons_filp = NULL;
581 struct file *filp, *f;
582 struct tty_file_private *priv;
583 int closecount = 0, n;
584 int refs;
585
586 if (!tty)
587 return;
588
589 f = tty_release_redirect(tty);
590
591 tty_lock(tty);
592
593 if (test_bit(TTY_HUPPED, &tty->flags)) {
594 tty_unlock(tty);
595 return;
596 }
597
598 /*
599 * Some console devices aren't actually hung up for technical and
600 * historical reasons, which can lead to indefinite interruptible
601 * sleep in n_tty_read(). The following explicitly tells
602 * n_tty_read() to abort readers.
603 */
604 set_bit(TTY_HUPPING, &tty->flags);
605
606 /* inuse_filps is protected by the single tty lock,
607 * this really needs to change if we want to flush the
608 * workqueue with the lock held.
609 */
610 check_tty_count(tty, "tty_hangup");
611
612 spin_lock(&tty->files_lock);
613 /* This breaks for file handles being sent over AF_UNIX sockets ? */
614 list_for_each_entry(priv, &tty->tty_files, list) {
615 filp = priv->file;
616 if (filp->f_op->write_iter == redirected_tty_write)
617 cons_filp = filp;
618 if (filp->f_op->write_iter != tty_write)
619 continue;
620 closecount++;
621 __tty_fasync(-1, filp, 0); /* can't block */
622 filp->f_op = &hung_up_tty_fops;
623 }
624 spin_unlock(&tty->files_lock);
625
626 refs = tty_signal_session_leader(tty, exit_session);
627 /* Account for the p->signal references we killed */
628 while (refs--)
629 tty_kref_put(tty);
630
631 tty_ldisc_hangup(tty, cons_filp != NULL);
632
633 spin_lock_irq(&tty->ctrl.lock);
634 clear_bit(TTY_THROTTLED, &tty->flags);
635 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
636 put_pid(tty->ctrl.session);
637 put_pid(tty->ctrl.pgrp);
638 tty->ctrl.session = NULL;
639 tty->ctrl.pgrp = NULL;
640 tty->ctrl.pktstatus = 0;
641 spin_unlock_irq(&tty->ctrl.lock);
642
643 /*
644 * If one of the devices matches a console pointer, we
645 * cannot just call hangup() because that will cause
646 * tty->count and state->count to go out of sync.
647 * So we just call close() the right number of times.
648 */
649 if (cons_filp) {
650 if (tty->ops->close)
651 for (n = 0; n < closecount; n++)
652 tty->ops->close(tty, cons_filp);
653 } else if (tty->ops->hangup)
654 tty->ops->hangup(tty);
655 /*
656 * We don't want to have driver/ldisc interactions beyond the ones
657 * we did here. The driver layer expects no calls after ->hangup()
658 * from the ldisc side, which is now guaranteed.
659 */
660 set_bit(TTY_HUPPED, &tty->flags);
661 clear_bit(TTY_HUPPING, &tty->flags);
662 tty_unlock(tty);
663
664 if (f)
665 fput(f);
666}
667
668static void do_tty_hangup(struct work_struct *work)
669{
670 struct tty_struct *tty =
671 container_of(work, struct tty_struct, hangup_work);
672
673 __tty_hangup(tty, 0);
674}
675
676/**
677 * tty_hangup - trigger a hangup event
678 * @tty: tty to hangup
679 *
680 * A carrier loss (virtual or otherwise) has occurred on @tty. Schedule a
681 * hangup sequence to run after this event.
682 */
683void tty_hangup(struct tty_struct *tty)
684{
685 tty_debug_hangup(tty, "hangup\n");
686 schedule_work(&tty->hangup_work);
687}
688EXPORT_SYMBOL(tty_hangup);
689
690/**
691 * tty_vhangup - process vhangup
692 * @tty: tty to hangup
693 *
694 * The user has asked via system call for the terminal to be hung up. We do
695 * this synchronously so that when the syscall returns the process is complete.
696 * That guarantee is necessary for security reasons.
697 */
698void tty_vhangup(struct tty_struct *tty)
699{
700 tty_debug_hangup(tty, "vhangup\n");
701 __tty_hangup(tty, 0);
702}
703EXPORT_SYMBOL(tty_vhangup);
704
705
706/**
707 * tty_vhangup_self - process vhangup for own ctty
708 *
709 * Perform a vhangup on the current controlling tty
710 */
711void tty_vhangup_self(void)
712{
713 struct tty_struct *tty;
714
715 tty = get_current_tty();
716 if (tty) {
717 tty_vhangup(tty);
718 tty_kref_put(tty);
719 }
720}
721
722/**
723 * tty_vhangup_session - hangup session leader exit
724 * @tty: tty to hangup
725 *
726 * The session leader is exiting and hanging up its controlling terminal.
727 * Every process in the foreground process group is signalled %SIGHUP.
728 *
729 * We do this synchronously so that when the syscall returns the process is
730 * complete. That guarantee is necessary for security reasons.
731 */
732void tty_vhangup_session(struct tty_struct *tty)
733{
734 tty_debug_hangup(tty, "session hangup\n");
735 __tty_hangup(tty, 1);
736}
737
738/**
739 * tty_hung_up_p - was tty hung up
740 * @filp: file pointer of tty
741 *
742 * Return: true if the tty has been subject to a vhangup or a carrier loss
743 */
744int tty_hung_up_p(struct file *filp)
745{
746 return (filp && filp->f_op == &hung_up_tty_fops);
747}
748EXPORT_SYMBOL(tty_hung_up_p);
749
750void __stop_tty(struct tty_struct *tty)
751{
752 if (tty->flow.stopped)
753 return;
754 tty->flow.stopped = true;
755 if (tty->ops->stop)
756 tty->ops->stop(tty);
757}
758
759/**
760 * stop_tty - propagate flow control
761 * @tty: tty to stop
762 *
763 * Perform flow control to the driver. May be called on an already stopped
764 * device and will not re-call the &tty_driver->stop() method.
765 *
766 * This functionality is used by both the line disciplines for halting incoming
767 * flow and by the driver. It may therefore be called from any context, may be
768 * under the tty %atomic_write_lock but not always.
769 *
770 * Locking:
771 * flow.lock
772 */
773void stop_tty(struct tty_struct *tty)
774{
775 unsigned long flags;
776
777 spin_lock_irqsave(&tty->flow.lock, flags);
778 __stop_tty(tty);
779 spin_unlock_irqrestore(&tty->flow.lock, flags);
780}
781EXPORT_SYMBOL(stop_tty);
782
783void __start_tty(struct tty_struct *tty)
784{
785 if (!tty->flow.stopped || tty->flow.tco_stopped)
786 return;
787 tty->flow.stopped = false;
788 if (tty->ops->start)
789 tty->ops->start(tty);
790 tty_wakeup(tty);
791}
792
793/**
794 * start_tty - propagate flow control
795 * @tty: tty to start
796 *
797 * Start a tty that has been stopped if at all possible. If @tty was previously
798 * stopped and is now being started, the &tty_driver->start() method is invoked
799 * and the line discipline woken.
800 *
801 * Locking:
802 * flow.lock
803 */
804void start_tty(struct tty_struct *tty)
805{
806 unsigned long flags;
807
808 spin_lock_irqsave(&tty->flow.lock, flags);
809 __start_tty(tty);
810 spin_unlock_irqrestore(&tty->flow.lock, flags);
811}
812EXPORT_SYMBOL(start_tty);
813
814static void tty_update_time(struct timespec64 *time)
815{
816 time64_t sec = ktime_get_real_seconds();
817
818 /*
819 * We only care if the two values differ in anything other than the
820 * lower three bits (i.e every 8 seconds). If so, then we can update
821 * the time of the tty device, otherwise it could be construded as a
822 * security leak to let userspace know the exact timing of the tty.
823 */
824 if ((sec ^ time->tv_sec) & ~7)
825 time->tv_sec = sec;
826}
827
828/*
829 * Iterate on the ldisc ->read() function until we've gotten all
830 * the data the ldisc has for us.
831 *
832 * The "cookie" is something that the ldisc read function can fill
833 * in to let us know that there is more data to be had.
834 *
835 * We promise to continue to call the ldisc until it stops returning
836 * data or clears the cookie. The cookie may be something that the
837 * ldisc maintains state for and needs to free.
838 */
839static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
840 struct file *file, struct iov_iter *to)
841{
842 int retval = 0;
843 void *cookie = NULL;
844 unsigned long offset = 0;
845 char kernel_buf[64];
846 size_t count = iov_iter_count(to);
847
848 do {
849 int size, copied;
850
851 size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count;
852 size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
853 if (!size)
854 break;
855
856 if (size < 0) {
857 /* Did we have an earlier error (ie -EFAULT)? */
858 if (retval)
859 break;
860 retval = size;
861
862 /*
863 * -EOVERFLOW means we didn't have enough space
864 * for a whole packet, and we shouldn't return
865 * a partial result.
866 */
867 if (retval == -EOVERFLOW)
868 offset = 0;
869 break;
870 }
871
872 copied = copy_to_iter(kernel_buf, size, to);
873 offset += copied;
874 count -= copied;
875
876 /*
877 * If the user copy failed, we still need to do another ->read()
878 * call if we had a cookie to let the ldisc clear up.
879 *
880 * But make sure size is zeroed.
881 */
882 if (unlikely(copied != size)) {
883 count = 0;
884 retval = -EFAULT;
885 }
886 } while (cookie);
887
888 /* We always clear tty buffer in case they contained passwords */
889 memzero_explicit(kernel_buf, sizeof(kernel_buf));
890 return offset ? offset : retval;
891}
892
893
894/**
895 * tty_read - read method for tty device files
896 * @iocb: kernel I/O control block
897 * @to: destination for the data read
898 *
899 * Perform the read system call function on this terminal device. Checks
900 * for hung up devices before calling the line discipline method.
901 *
902 * Locking:
903 * Locks the line discipline internally while needed. Multiple read calls
904 * may be outstanding in parallel.
905 */
906static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
907{
908 int i;
909 struct file *file = iocb->ki_filp;
910 struct inode *inode = file_inode(file);
911 struct tty_struct *tty = file_tty(file);
912 struct tty_ldisc *ld;
913
914 if (tty_paranoia_check(tty, inode, "tty_read"))
915 return -EIO;
916 if (!tty || tty_io_error(tty))
917 return -EIO;
918
919 /* We want to wait for the line discipline to sort out in this
920 * situation.
921 */
922 ld = tty_ldisc_ref_wait(tty);
923 if (!ld)
924 return hung_up_tty_read(iocb, to);
925 i = -EIO;
926 if (ld->ops->read)
927 i = iterate_tty_read(ld, tty, file, to);
928 tty_ldisc_deref(ld);
929
930 if (i > 0)
931 tty_update_time(&inode->i_atime);
932
933 return i;
934}
935
936static void tty_write_unlock(struct tty_struct *tty)
937{
938 mutex_unlock(&tty->atomic_write_lock);
939 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
940}
941
942static int tty_write_lock(struct tty_struct *tty, int ndelay)
943{
944 if (!mutex_trylock(&tty->atomic_write_lock)) {
945 if (ndelay)
946 return -EAGAIN;
947 if (mutex_lock_interruptible(&tty->atomic_write_lock))
948 return -ERESTARTSYS;
949 }
950 return 0;
951}
952
953/*
954 * Split writes up in sane blocksizes to avoid
955 * denial-of-service type attacks
956 */
957static inline ssize_t do_tty_write(
958 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
959 struct tty_struct *tty,
960 struct file *file,
961 struct iov_iter *from)
962{
963 size_t count = iov_iter_count(from);
964 ssize_t ret, written = 0;
965 unsigned int chunk;
966
967 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
968 if (ret < 0)
969 return ret;
970
971 /*
972 * We chunk up writes into a temporary buffer. This
973 * simplifies low-level drivers immensely, since they
974 * don't have locking issues and user mode accesses.
975 *
976 * But if TTY_NO_WRITE_SPLIT is set, we should use a
977 * big chunk-size..
978 *
979 * The default chunk-size is 2kB, because the NTTY
980 * layer has problems with bigger chunks. It will
981 * claim to be able to handle more characters than
982 * it actually does.
983 */
984 chunk = 2048;
985 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
986 chunk = 65536;
987 if (count < chunk)
988 chunk = count;
989
990 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
991 if (tty->write_cnt < chunk) {
992 unsigned char *buf_chunk;
993
994 if (chunk < 1024)
995 chunk = 1024;
996
997 buf_chunk = kvmalloc(chunk, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
998 if (!buf_chunk) {
999 ret = -ENOMEM;
1000 goto out;
1001 }
1002 kvfree(tty->write_buf);
1003 tty->write_cnt = chunk;
1004 tty->write_buf = buf_chunk;
1005 }
1006
1007 /* Do the write .. */
1008 for (;;) {
1009 size_t size = count;
1010
1011 if (size > chunk)
1012 size = chunk;
1013
1014 ret = -EFAULT;
1015 if (copy_from_iter(tty->write_buf, size, from) != size)
1016 break;
1017
1018 ret = write(tty, file, tty->write_buf, size);
1019 if (ret <= 0)
1020 break;
1021
1022 written += ret;
1023 if (ret > size)
1024 break;
1025
1026 /* FIXME! Have Al check this! */
1027 if (ret != size)
1028 iov_iter_revert(from, size-ret);
1029
1030 count -= ret;
1031 if (!count)
1032 break;
1033 ret = -ERESTARTSYS;
1034 if (signal_pending(current))
1035 break;
1036 cond_resched();
1037 }
1038 if (written) {
1039 tty_update_time(&file_inode(file)->i_mtime);
1040 ret = written;
1041 }
1042out:
1043 tty_write_unlock(tty);
1044 return ret;
1045}
1046
1047/**
1048 * tty_write_message - write a message to a certain tty, not just the console.
1049 * @tty: the destination tty_struct
1050 * @msg: the message to write
1051 *
1052 * This is used for messages that need to be redirected to a specific tty. We
1053 * don't put it into the syslog queue right now maybe in the future if really
1054 * needed.
1055 *
1056 * We must still hold the BTM and test the CLOSING flag for the moment.
1057 */
1058void tty_write_message(struct tty_struct *tty, char *msg)
1059{
1060 if (tty) {
1061 mutex_lock(&tty->atomic_write_lock);
1062 tty_lock(tty);
1063 if (tty->ops->write && tty->count > 0)
1064 tty->ops->write(tty, msg, strlen(msg));
1065 tty_unlock(tty);
1066 tty_write_unlock(tty);
1067 }
1068}
1069
1070static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_iter *from)
1071{
1072 struct tty_struct *tty = file_tty(file);
1073 struct tty_ldisc *ld;
1074 ssize_t ret;
1075
1076 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1077 return -EIO;
1078 if (!tty || !tty->ops->write || tty_io_error(tty))
1079 return -EIO;
1080 /* Short term debug to catch buggy drivers */
1081 if (tty->ops->write_room == NULL)
1082 tty_err(tty, "missing write_room method\n");
1083 ld = tty_ldisc_ref_wait(tty);
1084 if (!ld)
1085 return hung_up_tty_write(iocb, from);
1086 if (!ld->ops->write)
1087 ret = -EIO;
1088 else
1089 ret = do_tty_write(ld->ops->write, tty, file, from);
1090 tty_ldisc_deref(ld);
1091 return ret;
1092}
1093
1094/**
1095 * tty_write - write method for tty device file
1096 * @iocb: kernel I/O control block
1097 * @from: iov_iter with data to write
1098 *
1099 * Write data to a tty device via the line discipline.
1100 *
1101 * Locking:
1102 * Locks the line discipline as required
1103 * Writes to the tty driver are serialized by the atomic_write_lock
1104 * and are then processed in chunks to the device. The line
1105 * discipline write method will not be invoked in parallel for
1106 * each device.
1107 */
1108static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from)
1109{
1110 return file_tty_write(iocb->ki_filp, iocb, from);
1111}
1112
1113ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter)
1114{
1115 struct file *p = NULL;
1116
1117 spin_lock(&redirect_lock);
1118 if (redirect)
1119 p = get_file(redirect);
1120 spin_unlock(&redirect_lock);
1121
1122 /*
1123 * We know the redirected tty is just another tty, we can
1124 * call file_tty_write() directly with that file pointer.
1125 */
1126 if (p) {
1127 ssize_t res;
1128
1129 res = file_tty_write(p, iocb, iter);
1130 fput(p);
1131 return res;
1132 }
1133 return tty_write(iocb, iter);
1134}
1135
1136/**
1137 * tty_send_xchar - send priority character
1138 * @tty: the tty to send to
1139 * @ch: xchar to send
1140 *
1141 * Send a high priority character to the tty even if stopped.
1142 *
1143 * Locking: none for xchar method, write ordering for write method.
1144 */
1145int tty_send_xchar(struct tty_struct *tty, char ch)
1146{
1147 bool was_stopped = tty->flow.stopped;
1148
1149 if (tty->ops->send_xchar) {
1150 down_read(&tty->termios_rwsem);
1151 tty->ops->send_xchar(tty, ch);
1152 up_read(&tty->termios_rwsem);
1153 return 0;
1154 }
1155
1156 if (tty_write_lock(tty, 0) < 0)
1157 return -ERESTARTSYS;
1158
1159 down_read(&tty->termios_rwsem);
1160 if (was_stopped)
1161 start_tty(tty);
1162 tty->ops->write(tty, &ch, 1);
1163 if (was_stopped)
1164 stop_tty(tty);
1165 up_read(&tty->termios_rwsem);
1166 tty_write_unlock(tty);
1167 return 0;
1168}
1169
1170/**
1171 * pty_line_name - generate name for a pty
1172 * @driver: the tty driver in use
1173 * @index: the minor number
1174 * @p: output buffer of at least 6 bytes
1175 *
1176 * Generate a name from a @driver reference and write it to the output buffer
1177 * @p.
1178 *
1179 * Locking: None
1180 */
1181static void pty_line_name(struct tty_driver *driver, int index, char *p)
1182{
1183 static const char ptychar[] = "pqrstuvwxyzabcde";
1184 int i = index + driver->name_base;
1185 /* ->name is initialized to "ttyp", but "tty" is expected */
1186 sprintf(p, "%s%c%x",
1187 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1188 ptychar[i >> 4 & 0xf], i & 0xf);
1189}
1190
1191/**
1192 * tty_line_name - generate name for a tty
1193 * @driver: the tty driver in use
1194 * @index: the minor number
1195 * @p: output buffer of at least 7 bytes
1196 *
1197 * Generate a name from a @driver reference and write it to the output buffer
1198 * @p.
1199 *
1200 * Locking: None
1201 */
1202static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1203{
1204 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1205 return sprintf(p, "%s", driver->name);
1206 else
1207 return sprintf(p, "%s%d", driver->name,
1208 index + driver->name_base);
1209}
1210
1211/**
1212 * tty_driver_lookup_tty() - find an existing tty, if any
1213 * @driver: the driver for the tty
1214 * @file: file object
1215 * @idx: the minor number
1216 *
1217 * Return: the tty, if found. If not found, return %NULL or ERR_PTR() if the
1218 * driver lookup() method returns an error.
1219 *
1220 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1221 */
1222static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1223 struct file *file, int idx)
1224{
1225 struct tty_struct *tty;
1226
1227 if (driver->ops->lookup)
1228 if (!file)
1229 tty = ERR_PTR(-EIO);
1230 else
1231 tty = driver->ops->lookup(driver, file, idx);
1232 else
1233 tty = driver->ttys[idx];
1234
1235 if (!IS_ERR(tty))
1236 tty_kref_get(tty);
1237 return tty;
1238}
1239
1240/**
1241 * tty_init_termios - helper for termios setup
1242 * @tty: the tty to set up
1243 *
1244 * Initialise the termios structure for this tty. This runs under the
1245 * %tty_mutex currently so we can be relaxed about ordering.
1246 */
1247void tty_init_termios(struct tty_struct *tty)
1248{
1249 struct ktermios *tp;
1250 int idx = tty->index;
1251
1252 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1253 tty->termios = tty->driver->init_termios;
1254 else {
1255 /* Check for lazy saved data */
1256 tp = tty->driver->termios[idx];
1257 if (tp != NULL) {
1258 tty->termios = *tp;
1259 tty->termios.c_line = tty->driver->init_termios.c_line;
1260 } else
1261 tty->termios = tty->driver->init_termios;
1262 }
1263 /* Compatibility until drivers always set this */
1264 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1265 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1266}
1267EXPORT_SYMBOL_GPL(tty_init_termios);
1268
1269/**
1270 * tty_standard_install - usual tty->ops->install
1271 * @driver: the driver for the tty
1272 * @tty: the tty
1273 *
1274 * If the @driver overrides @tty->ops->install, it still can call this function
1275 * to perform the standard install operations.
1276 */
1277int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1278{
1279 tty_init_termios(tty);
1280 tty_driver_kref_get(driver);
1281 tty->count++;
1282 driver->ttys[tty->index] = tty;
1283 return 0;
1284}
1285EXPORT_SYMBOL_GPL(tty_standard_install);
1286
1287/**
1288 * tty_driver_install_tty() - install a tty entry in the driver
1289 * @driver: the driver for the tty
1290 * @tty: the tty
1291 *
1292 * Install a tty object into the driver tables. The @tty->index field will be
1293 * set by the time this is called. This method is responsible for ensuring any
1294 * need additional structures are allocated and configured.
1295 *
1296 * Locking: tty_mutex for now
1297 */
1298static int tty_driver_install_tty(struct tty_driver *driver,
1299 struct tty_struct *tty)
1300{
1301 return driver->ops->install ? driver->ops->install(driver, tty) :
1302 tty_standard_install(driver, tty);
1303}
1304
1305/**
1306 * tty_driver_remove_tty() - remove a tty from the driver tables
1307 * @driver: the driver for the tty
1308 * @tty: tty to remove
1309 *
1310 * Remove a tty object from the driver tables. The tty->index field will be set
1311 * by the time this is called.
1312 *
1313 * Locking: tty_mutex for now
1314 */
1315static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1316{
1317 if (driver->ops->remove)
1318 driver->ops->remove(driver, tty);
1319 else
1320 driver->ttys[tty->index] = NULL;
1321}
1322
1323/**
1324 * tty_reopen() - fast re-open of an open tty
1325 * @tty: the tty to open
1326 *
1327 * Re-opens on master ptys are not allowed and return -%EIO.
1328 *
1329 * Locking: Caller must hold tty_lock
1330 * Return: 0 on success, -errno on error.
1331 */
1332static int tty_reopen(struct tty_struct *tty)
1333{
1334 struct tty_driver *driver = tty->driver;
1335 struct tty_ldisc *ld;
1336 int retval = 0;
1337
1338 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1339 driver->subtype == PTY_TYPE_MASTER)
1340 return -EIO;
1341
1342 if (!tty->count)
1343 return -EAGAIN;
1344
1345 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1346 return -EBUSY;
1347
1348 ld = tty_ldisc_ref_wait(tty);
1349 if (ld) {
1350 tty_ldisc_deref(ld);
1351 } else {
1352 retval = tty_ldisc_lock(tty, 5 * HZ);
1353 if (retval)
1354 return retval;
1355
1356 if (!tty->ldisc)
1357 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1358 tty_ldisc_unlock(tty);
1359 }
1360
1361 if (retval == 0)
1362 tty->count++;
1363
1364 return retval;
1365}
1366
1367/**
1368 * tty_init_dev - initialise a tty device
1369 * @driver: tty driver we are opening a device on
1370 * @idx: device index
1371 *
1372 * Prepare a tty device. This may not be a "new" clean device but could also be
1373 * an active device. The pty drivers require special handling because of this.
1374 *
1375 * Locking:
1376 * The function is called under the tty_mutex, which protects us from the
1377 * tty struct or driver itself going away.
1378 *
1379 * On exit the tty device has the line discipline attached and a reference
1380 * count of 1. If a pair was created for pty/tty use and the other was a pty
1381 * master then it too has a reference count of 1.
1382 *
1383 * WSH 06/09/97: Rewritten to remove races and properly clean up after a failed
1384 * open. The new code protects the open with a mutex, so it's really quite
1385 * straightforward. The mutex locking can probably be relaxed for the (most
1386 * common) case of reopening a tty.
1387 *
1388 * Return: new tty structure
1389 */
1390struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1391{
1392 struct tty_struct *tty;
1393 int retval;
1394
1395 /*
1396 * First time open is complex, especially for PTY devices.
1397 * This code guarantees that either everything succeeds and the
1398 * TTY is ready for operation, or else the table slots are vacated
1399 * and the allocated memory released. (Except that the termios
1400 * may be retained.)
1401 */
1402
1403 if (!try_module_get(driver->owner))
1404 return ERR_PTR(-ENODEV);
1405
1406 tty = alloc_tty_struct(driver, idx);
1407 if (!tty) {
1408 retval = -ENOMEM;
1409 goto err_module_put;
1410 }
1411
1412 tty_lock(tty);
1413 retval = tty_driver_install_tty(driver, tty);
1414 if (retval < 0)
1415 goto err_free_tty;
1416
1417 if (!tty->port)
1418 tty->port = driver->ports[idx];
1419
1420 if (WARN_RATELIMIT(!tty->port,
1421 "%s: %s driver does not set tty->port. This would crash the kernel. Fix the driver!\n",
1422 __func__, tty->driver->name)) {
1423 retval = -EINVAL;
1424 goto err_release_lock;
1425 }
1426
1427 retval = tty_ldisc_lock(tty, 5 * HZ);
1428 if (retval)
1429 goto err_release_lock;
1430 tty->port->itty = tty;
1431
1432 /*
1433 * Structures all installed ... call the ldisc open routines.
1434 * If we fail here just call release_tty to clean up. No need
1435 * to decrement the use counts, as release_tty doesn't care.
1436 */
1437 retval = tty_ldisc_setup(tty, tty->link);
1438 if (retval)
1439 goto err_release_tty;
1440 tty_ldisc_unlock(tty);
1441 /* Return the tty locked so that it cannot vanish under the caller */
1442 return tty;
1443
1444err_free_tty:
1445 tty_unlock(tty);
1446 free_tty_struct(tty);
1447err_module_put:
1448 module_put(driver->owner);
1449 return ERR_PTR(retval);
1450
1451 /* call the tty release_tty routine to clean out this slot */
1452err_release_tty:
1453 tty_ldisc_unlock(tty);
1454 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1455 retval, idx);
1456err_release_lock:
1457 tty_unlock(tty);
1458 release_tty(tty, idx);
1459 return ERR_PTR(retval);
1460}
1461
1462/**
1463 * tty_save_termios() - save tty termios data in driver table
1464 * @tty: tty whose termios data to save
1465 *
1466 * Locking: Caller guarantees serialisation with tty_init_termios().
1467 */
1468void tty_save_termios(struct tty_struct *tty)
1469{
1470 struct ktermios *tp;
1471 int idx = tty->index;
1472
1473 /* If the port is going to reset then it has no termios to save */
1474 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1475 return;
1476
1477 /* Stash the termios data */
1478 tp = tty->driver->termios[idx];
1479 if (tp == NULL) {
1480 tp = kmalloc(sizeof(*tp), GFP_KERNEL);
1481 if (tp == NULL)
1482 return;
1483 tty->driver->termios[idx] = tp;
1484 }
1485 *tp = tty->termios;
1486}
1487EXPORT_SYMBOL_GPL(tty_save_termios);
1488
1489/**
1490 * tty_flush_works - flush all works of a tty/pty pair
1491 * @tty: tty device to flush works for (or either end of a pty pair)
1492 *
1493 * Sync flush all works belonging to @tty (and the 'other' tty).
1494 */
1495static void tty_flush_works(struct tty_struct *tty)
1496{
1497 flush_work(&tty->SAK_work);
1498 flush_work(&tty->hangup_work);
1499 if (tty->link) {
1500 flush_work(&tty->link->SAK_work);
1501 flush_work(&tty->link->hangup_work);
1502 }
1503}
1504
1505/**
1506 * release_one_tty - release tty structure memory
1507 * @work: work of tty we are obliterating
1508 *
1509 * Releases memory associated with a tty structure, and clears out the
1510 * driver table slots. This function is called when a device is no longer
1511 * in use. It also gets called when setup of a device fails.
1512 *
1513 * Locking:
1514 * takes the file list lock internally when working on the list of ttys
1515 * that the driver keeps.
1516 *
1517 * This method gets called from a work queue so that the driver private
1518 * cleanup ops can sleep (needed for USB at least)
1519 */
1520static void release_one_tty(struct work_struct *work)
1521{
1522 struct tty_struct *tty =
1523 container_of(work, struct tty_struct, hangup_work);
1524 struct tty_driver *driver = tty->driver;
1525 struct module *owner = driver->owner;
1526
1527 if (tty->ops->cleanup)
1528 tty->ops->cleanup(tty);
1529
1530 tty_driver_kref_put(driver);
1531 module_put(owner);
1532
1533 spin_lock(&tty->files_lock);
1534 list_del_init(&tty->tty_files);
1535 spin_unlock(&tty->files_lock);
1536
1537 put_pid(tty->ctrl.pgrp);
1538 put_pid(tty->ctrl.session);
1539 free_tty_struct(tty);
1540}
1541
1542static void queue_release_one_tty(struct kref *kref)
1543{
1544 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1545
1546 /* The hangup queue is now free so we can reuse it rather than
1547 * waste a chunk of memory for each port.
1548 */
1549 INIT_WORK(&tty->hangup_work, release_one_tty);
1550 schedule_work(&tty->hangup_work);
1551}
1552
1553/**
1554 * tty_kref_put - release a tty kref
1555 * @tty: tty device
1556 *
1557 * Release a reference to the @tty device and if need be let the kref layer
1558 * destruct the object for us.
1559 */
1560void tty_kref_put(struct tty_struct *tty)
1561{
1562 if (tty)
1563 kref_put(&tty->kref, queue_release_one_tty);
1564}
1565EXPORT_SYMBOL(tty_kref_put);
1566
1567/**
1568 * release_tty - release tty structure memory
1569 * @tty: tty device release
1570 * @idx: index of the tty device release
1571 *
1572 * Release both @tty and a possible linked partner (think pty pair),
1573 * and decrement the refcount of the backing module.
1574 *
1575 * Locking:
1576 * tty_mutex
1577 * takes the file list lock internally when working on the list of ttys
1578 * that the driver keeps.
1579 */
1580static void release_tty(struct tty_struct *tty, int idx)
1581{
1582 /* This should always be true but check for the moment */
1583 WARN_ON(tty->index != idx);
1584 WARN_ON(!mutex_is_locked(&tty_mutex));
1585 if (tty->ops->shutdown)
1586 tty->ops->shutdown(tty);
1587 tty_save_termios(tty);
1588 tty_driver_remove_tty(tty->driver, tty);
1589 if (tty->port)
1590 tty->port->itty = NULL;
1591 if (tty->link)
1592 tty->link->port->itty = NULL;
1593 if (tty->port)
1594 tty_buffer_cancel_work(tty->port);
1595 if (tty->link)
1596 tty_buffer_cancel_work(tty->link->port);
1597
1598 tty_kref_put(tty->link);
1599 tty_kref_put(tty);
1600}
1601
1602/**
1603 * tty_release_checks - check a tty before real release
1604 * @tty: tty to check
1605 * @idx: index of the tty
1606 *
1607 * Performs some paranoid checking before true release of the @tty. This is a
1608 * no-op unless %TTY_PARANOIA_CHECK is defined.
1609 */
1610static int tty_release_checks(struct tty_struct *tty, int idx)
1611{
1612#ifdef TTY_PARANOIA_CHECK
1613 if (idx < 0 || idx >= tty->driver->num) {
1614 tty_debug(tty, "bad idx %d\n", idx);
1615 return -1;
1616 }
1617
1618 /* not much to check for devpts */
1619 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1620 return 0;
1621
1622 if (tty != tty->driver->ttys[idx]) {
1623 tty_debug(tty, "bad driver table[%d] = %p\n",
1624 idx, tty->driver->ttys[idx]);
1625 return -1;
1626 }
1627 if (tty->driver->other) {
1628 struct tty_struct *o_tty = tty->link;
1629
1630 if (o_tty != tty->driver->other->ttys[idx]) {
1631 tty_debug(tty, "bad other table[%d] = %p\n",
1632 idx, tty->driver->other->ttys[idx]);
1633 return -1;
1634 }
1635 if (o_tty->link != tty) {
1636 tty_debug(tty, "bad link = %p\n", o_tty->link);
1637 return -1;
1638 }
1639 }
1640#endif
1641 return 0;
1642}
1643
1644/**
1645 * tty_kclose - closes tty opened by tty_kopen
1646 * @tty: tty device
1647 *
1648 * Performs the final steps to release and free a tty device. It is the same as
1649 * tty_release_struct() except that it also resets %TTY_PORT_KOPENED flag on
1650 * @tty->port.
1651 */
1652void tty_kclose(struct tty_struct *tty)
1653{
1654 /*
1655 * Ask the line discipline code to release its structures
1656 */
1657 tty_ldisc_release(tty);
1658
1659 /* Wait for pending work before tty destruction commences */
1660 tty_flush_works(tty);
1661
1662 tty_debug_hangup(tty, "freeing structure\n");
1663 /*
1664 * The release_tty function takes care of the details of clearing
1665 * the slots and preserving the termios structure.
1666 */
1667 mutex_lock(&tty_mutex);
1668 tty_port_set_kopened(tty->port, 0);
1669 release_tty(tty, tty->index);
1670 mutex_unlock(&tty_mutex);
1671}
1672EXPORT_SYMBOL_GPL(tty_kclose);
1673
1674/**
1675 * tty_release_struct - release a tty struct
1676 * @tty: tty device
1677 * @idx: index of the tty
1678 *
1679 * Performs the final steps to release and free a tty device. It is roughly the
1680 * reverse of tty_init_dev().
1681 */
1682void tty_release_struct(struct tty_struct *tty, int idx)
1683{
1684 /*
1685 * Ask the line discipline code to release its structures
1686 */
1687 tty_ldisc_release(tty);
1688
1689 /* Wait for pending work before tty destruction commmences */
1690 tty_flush_works(tty);
1691
1692 tty_debug_hangup(tty, "freeing structure\n");
1693 /*
1694 * The release_tty function takes care of the details of clearing
1695 * the slots and preserving the termios structure.
1696 */
1697 mutex_lock(&tty_mutex);
1698 release_tty(tty, idx);
1699 mutex_unlock(&tty_mutex);
1700}
1701EXPORT_SYMBOL_GPL(tty_release_struct);
1702
1703/**
1704 * tty_release - vfs callback for close
1705 * @inode: inode of tty
1706 * @filp: file pointer for handle to tty
1707 *
1708 * Called the last time each file handle is closed that references this tty.
1709 * There may however be several such references.
1710 *
1711 * Locking:
1712 * Takes BKL. See tty_release_dev().
1713 *
1714 * Even releasing the tty structures is a tricky business. We have to be very
1715 * careful that the structures are all released at the same time, as interrupts
1716 * might otherwise get the wrong pointers.
1717 *
1718 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1719 * lead to double frees or releasing memory still in use.
1720 */
1721int tty_release(struct inode *inode, struct file *filp)
1722{
1723 struct tty_struct *tty = file_tty(filp);
1724 struct tty_struct *o_tty = NULL;
1725 int do_sleep, final;
1726 int idx;
1727 long timeout = 0;
1728 int once = 1;
1729
1730 if (tty_paranoia_check(tty, inode, __func__))
1731 return 0;
1732
1733 tty_lock(tty);
1734 check_tty_count(tty, __func__);
1735
1736 __tty_fasync(-1, filp, 0);
1737
1738 idx = tty->index;
1739 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1740 tty->driver->subtype == PTY_TYPE_MASTER)
1741 o_tty = tty->link;
1742
1743 if (tty_release_checks(tty, idx)) {
1744 tty_unlock(tty);
1745 return 0;
1746 }
1747
1748 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1749
1750 if (tty->ops->close)
1751 tty->ops->close(tty, filp);
1752
1753 /* If tty is pty master, lock the slave pty (stable lock order) */
1754 tty_lock_slave(o_tty);
1755
1756 /*
1757 * Sanity check: if tty->count is going to zero, there shouldn't be
1758 * any waiters on tty->read_wait or tty->write_wait. We test the
1759 * wait queues and kick everyone out _before_ actually starting to
1760 * close. This ensures that we won't block while releasing the tty
1761 * structure.
1762 *
1763 * The test for the o_tty closing is necessary, since the master and
1764 * slave sides may close in any order. If the slave side closes out
1765 * first, its count will be one, since the master side holds an open.
1766 * Thus this test wouldn't be triggered at the time the slave closed,
1767 * so we do it now.
1768 */
1769 while (1) {
1770 do_sleep = 0;
1771
1772 if (tty->count <= 1) {
1773 if (waitqueue_active(&tty->read_wait)) {
1774 wake_up_poll(&tty->read_wait, EPOLLIN);
1775 do_sleep++;
1776 }
1777 if (waitqueue_active(&tty->write_wait)) {
1778 wake_up_poll(&tty->write_wait, EPOLLOUT);
1779 do_sleep++;
1780 }
1781 }
1782 if (o_tty && o_tty->count <= 1) {
1783 if (waitqueue_active(&o_tty->read_wait)) {
1784 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1785 do_sleep++;
1786 }
1787 if (waitqueue_active(&o_tty->write_wait)) {
1788 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1789 do_sleep++;
1790 }
1791 }
1792 if (!do_sleep)
1793 break;
1794
1795 if (once) {
1796 once = 0;
1797 tty_warn(tty, "read/write wait queue active!\n");
1798 }
1799 schedule_timeout_killable(timeout);
1800 if (timeout < 120 * HZ)
1801 timeout = 2 * timeout + 1;
1802 else
1803 timeout = MAX_SCHEDULE_TIMEOUT;
1804 }
1805
1806 if (o_tty) {
1807 if (--o_tty->count < 0) {
1808 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1809 o_tty->count = 0;
1810 }
1811 }
1812 if (--tty->count < 0) {
1813 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1814 tty->count = 0;
1815 }
1816
1817 /*
1818 * We've decremented tty->count, so we need to remove this file
1819 * descriptor off the tty->tty_files list; this serves two
1820 * purposes:
1821 * - check_tty_count sees the correct number of file descriptors
1822 * associated with this tty.
1823 * - do_tty_hangup no longer sees this file descriptor as
1824 * something that needs to be handled for hangups.
1825 */
1826 tty_del_file(filp);
1827
1828 /*
1829 * Perform some housekeeping before deciding whether to return.
1830 *
1831 * If _either_ side is closing, make sure there aren't any
1832 * processes that still think tty or o_tty is their controlling
1833 * tty.
1834 */
1835 if (!tty->count) {
1836 read_lock(&tasklist_lock);
1837 session_clear_tty(tty->ctrl.session);
1838 if (o_tty)
1839 session_clear_tty(o_tty->ctrl.session);
1840 read_unlock(&tasklist_lock);
1841 }
1842
1843 /* check whether both sides are closing ... */
1844 final = !tty->count && !(o_tty && o_tty->count);
1845
1846 tty_unlock_slave(o_tty);
1847 tty_unlock(tty);
1848
1849 /* At this point, the tty->count == 0 should ensure a dead tty
1850 * cannot be re-opened by a racing opener.
1851 */
1852
1853 if (!final)
1854 return 0;
1855
1856 tty_debug_hangup(tty, "final close\n");
1857
1858 tty_release_struct(tty, idx);
1859 return 0;
1860}
1861
1862/**
1863 * tty_open_current_tty - get locked tty of current task
1864 * @device: device number
1865 * @filp: file pointer to tty
1866 * @return: locked tty of the current task iff @device is /dev/tty
1867 *
1868 * Performs a re-open of the current task's controlling tty.
1869 *
1870 * We cannot return driver and index like for the other nodes because devpts
1871 * will not work then. It expects inodes to be from devpts FS.
1872 */
1873static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1874{
1875 struct tty_struct *tty;
1876 int retval;
1877
1878 if (device != MKDEV(TTYAUX_MAJOR, 0))
1879 return NULL;
1880
1881 tty = get_current_tty();
1882 if (!tty)
1883 return ERR_PTR(-ENXIO);
1884
1885 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1886 /* noctty = 1; */
1887 tty_lock(tty);
1888 tty_kref_put(tty); /* safe to drop the kref now */
1889
1890 retval = tty_reopen(tty);
1891 if (retval < 0) {
1892 tty_unlock(tty);
1893 tty = ERR_PTR(retval);
1894 }
1895 return tty;
1896}
1897
1898/**
1899 * tty_lookup_driver - lookup a tty driver for a given device file
1900 * @device: device number
1901 * @filp: file pointer to tty
1902 * @index: index for the device in the @return driver
1903 *
1904 * If returned value is not erroneous, the caller is responsible to decrement
1905 * the refcount by tty_driver_kref_put().
1906 *
1907 * Locking: %tty_mutex protects get_tty_driver()
1908 *
1909 * Return: driver for this inode (with increased refcount)
1910 */
1911static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1912 int *index)
1913{
1914 struct tty_driver *driver = NULL;
1915
1916 switch (device) {
1917#ifdef CONFIG_VT
1918 case MKDEV(TTY_MAJOR, 0): {
1919 extern struct tty_driver *console_driver;
1920
1921 driver = tty_driver_kref_get(console_driver);
1922 *index = fg_console;
1923 break;
1924 }
1925#endif
1926 case MKDEV(TTYAUX_MAJOR, 1): {
1927 struct tty_driver *console_driver = console_device(index);
1928
1929 if (console_driver) {
1930 driver = tty_driver_kref_get(console_driver);
1931 if (driver && filp) {
1932 /* Don't let /dev/console block */
1933 filp->f_flags |= O_NONBLOCK;
1934 break;
1935 }
1936 }
1937 if (driver)
1938 tty_driver_kref_put(driver);
1939 return ERR_PTR(-ENODEV);
1940 }
1941 default:
1942 driver = get_tty_driver(device, index);
1943 if (!driver)
1944 return ERR_PTR(-ENODEV);
1945 break;
1946 }
1947 return driver;
1948}
1949
1950static struct tty_struct *tty_kopen(dev_t device, int shared)
1951{
1952 struct tty_struct *tty;
1953 struct tty_driver *driver;
1954 int index = -1;
1955
1956 mutex_lock(&tty_mutex);
1957 driver = tty_lookup_driver(device, NULL, &index);
1958 if (IS_ERR(driver)) {
1959 mutex_unlock(&tty_mutex);
1960 return ERR_CAST(driver);
1961 }
1962
1963 /* check whether we're reopening an existing tty */
1964 tty = tty_driver_lookup_tty(driver, NULL, index);
1965 if (IS_ERR(tty) || shared)
1966 goto out;
1967
1968 if (tty) {
1969 /* drop kref from tty_driver_lookup_tty() */
1970 tty_kref_put(tty);
1971 tty = ERR_PTR(-EBUSY);
1972 } else { /* tty_init_dev returns tty with the tty_lock held */
1973 tty = tty_init_dev(driver, index);
1974 if (IS_ERR(tty))
1975 goto out;
1976 tty_port_set_kopened(tty->port, 1);
1977 }
1978out:
1979 mutex_unlock(&tty_mutex);
1980 tty_driver_kref_put(driver);
1981 return tty;
1982}
1983
1984/**
1985 * tty_kopen_exclusive - open a tty device for kernel
1986 * @device: dev_t of device to open
1987 *
1988 * Opens tty exclusively for kernel. Performs the driver lookup, makes sure
1989 * it's not already opened and performs the first-time tty initialization.
1990 *
1991 * Claims the global %tty_mutex to serialize:
1992 * * concurrent first-time tty initialization
1993 * * concurrent tty driver removal w/ lookup
1994 * * concurrent tty removal from driver table
1995 *
1996 * Return: the locked initialized &tty_struct
1997 */
1998struct tty_struct *tty_kopen_exclusive(dev_t device)
1999{
2000 return tty_kopen(device, 0);
2001}
2002EXPORT_SYMBOL_GPL(tty_kopen_exclusive);
2003
2004/**
2005 * tty_kopen_shared - open a tty device for shared in-kernel use
2006 * @device: dev_t of device to open
2007 *
2008 * Opens an already existing tty for in-kernel use. Compared to
2009 * tty_kopen_exclusive() above it doesn't ensure to be the only user.
2010 *
2011 * Locking: identical to tty_kopen() above.
2012 */
2013struct tty_struct *tty_kopen_shared(dev_t device)
2014{
2015 return tty_kopen(device, 1);
2016}
2017EXPORT_SYMBOL_GPL(tty_kopen_shared);
2018
2019/**
2020 * tty_open_by_driver - open a tty device
2021 * @device: dev_t of device to open
2022 * @filp: file pointer to tty
2023 *
2024 * Performs the driver lookup, checks for a reopen, or otherwise performs the
2025 * first-time tty initialization.
2026 *
2027 *
2028 * Claims the global tty_mutex to serialize:
2029 * * concurrent first-time tty initialization
2030 * * concurrent tty driver removal w/ lookup
2031 * * concurrent tty removal from driver table
2032 *
2033 * Return: the locked initialized or re-opened &tty_struct
2034 */
2035static struct tty_struct *tty_open_by_driver(dev_t device,
2036 struct file *filp)
2037{
2038 struct tty_struct *tty;
2039 struct tty_driver *driver = NULL;
2040 int index = -1;
2041 int retval;
2042
2043 mutex_lock(&tty_mutex);
2044 driver = tty_lookup_driver(device, filp, &index);
2045 if (IS_ERR(driver)) {
2046 mutex_unlock(&tty_mutex);
2047 return ERR_CAST(driver);
2048 }
2049
2050 /* check whether we're reopening an existing tty */
2051 tty = tty_driver_lookup_tty(driver, filp, index);
2052 if (IS_ERR(tty)) {
2053 mutex_unlock(&tty_mutex);
2054 goto out;
2055 }
2056
2057 if (tty) {
2058 if (tty_port_kopened(tty->port)) {
2059 tty_kref_put(tty);
2060 mutex_unlock(&tty_mutex);
2061 tty = ERR_PTR(-EBUSY);
2062 goto out;
2063 }
2064 mutex_unlock(&tty_mutex);
2065 retval = tty_lock_interruptible(tty);
2066 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2067 if (retval) {
2068 if (retval == -EINTR)
2069 retval = -ERESTARTSYS;
2070 tty = ERR_PTR(retval);
2071 goto out;
2072 }
2073 retval = tty_reopen(tty);
2074 if (retval < 0) {
2075 tty_unlock(tty);
2076 tty = ERR_PTR(retval);
2077 }
2078 } else { /* Returns with the tty_lock held for now */
2079 tty = tty_init_dev(driver, index);
2080 mutex_unlock(&tty_mutex);
2081 }
2082out:
2083 tty_driver_kref_put(driver);
2084 return tty;
2085}
2086
2087/**
2088 * tty_open - open a tty device
2089 * @inode: inode of device file
2090 * @filp: file pointer to tty
2091 *
2092 * tty_open() and tty_release() keep up the tty count that contains the number
2093 * of opens done on a tty. We cannot use the inode-count, as different inodes
2094 * might point to the same tty.
2095 *
2096 * Open-counting is needed for pty masters, as well as for keeping track of
2097 * serial lines: DTR is dropped when the last close happens.
2098 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2099 *
2100 * The termios state of a pty is reset on the first open so that settings don't
2101 * persist across reuse.
2102 *
2103 * Locking:
2104 * * %tty_mutex protects tty, tty_lookup_driver() and tty_init_dev().
2105 * * @tty->count should protect the rest.
2106 * * ->siglock protects ->signal/->sighand
2107 *
2108 * Note: the tty_unlock/lock cases without a ref are only safe due to %tty_mutex
2109 */
2110static int tty_open(struct inode *inode, struct file *filp)
2111{
2112 struct tty_struct *tty;
2113 int noctty, retval;
2114 dev_t device = inode->i_rdev;
2115 unsigned saved_flags = filp->f_flags;
2116
2117 nonseekable_open(inode, filp);
2118
2119retry_open:
2120 retval = tty_alloc_file(filp);
2121 if (retval)
2122 return -ENOMEM;
2123
2124 tty = tty_open_current_tty(device, filp);
2125 if (!tty)
2126 tty = tty_open_by_driver(device, filp);
2127
2128 if (IS_ERR(tty)) {
2129 tty_free_file(filp);
2130 retval = PTR_ERR(tty);
2131 if (retval != -EAGAIN || signal_pending(current))
2132 return retval;
2133 schedule();
2134 goto retry_open;
2135 }
2136
2137 tty_add_file(tty, filp);
2138
2139 check_tty_count(tty, __func__);
2140 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2141
2142 if (tty->ops->open)
2143 retval = tty->ops->open(tty, filp);
2144 else
2145 retval = -ENODEV;
2146 filp->f_flags = saved_flags;
2147
2148 if (retval) {
2149 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2150
2151 tty_unlock(tty); /* need to call tty_release without BTM */
2152 tty_release(inode, filp);
2153 if (retval != -ERESTARTSYS)
2154 return retval;
2155
2156 if (signal_pending(current))
2157 return retval;
2158
2159 schedule();
2160 /*
2161 * Need to reset f_op in case a hangup happened.
2162 */
2163 if (tty_hung_up_p(filp))
2164 filp->f_op = &tty_fops;
2165 goto retry_open;
2166 }
2167 clear_bit(TTY_HUPPED, &tty->flags);
2168
2169 noctty = (filp->f_flags & O_NOCTTY) ||
2170 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2171 device == MKDEV(TTYAUX_MAJOR, 1) ||
2172 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2173 tty->driver->subtype == PTY_TYPE_MASTER);
2174 if (!noctty)
2175 tty_open_proc_set_tty(filp, tty);
2176 tty_unlock(tty);
2177 return 0;
2178}
2179
2180
2181/**
2182 * tty_poll - check tty status
2183 * @filp: file being polled
2184 * @wait: poll wait structures to update
2185 *
2186 * Call the line discipline polling method to obtain the poll status of the
2187 * device.
2188 *
2189 * Locking: locks called line discipline but ldisc poll method may be
2190 * re-entered freely by other callers.
2191 */
2192static __poll_t tty_poll(struct file *filp, poll_table *wait)
2193{
2194 struct tty_struct *tty = file_tty(filp);
2195 struct tty_ldisc *ld;
2196 __poll_t ret = 0;
2197
2198 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2199 return 0;
2200
2201 ld = tty_ldisc_ref_wait(tty);
2202 if (!ld)
2203 return hung_up_tty_poll(filp, wait);
2204 if (ld->ops->poll)
2205 ret = ld->ops->poll(tty, filp, wait);
2206 tty_ldisc_deref(ld);
2207 return ret;
2208}
2209
2210static int __tty_fasync(int fd, struct file *filp, int on)
2211{
2212 struct tty_struct *tty = file_tty(filp);
2213 unsigned long flags;
2214 int retval = 0;
2215
2216 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2217 goto out;
2218
2219 retval = fasync_helper(fd, filp, on, &tty->fasync);
2220 if (retval <= 0)
2221 goto out;
2222
2223 if (on) {
2224 enum pid_type type;
2225 struct pid *pid;
2226
2227 spin_lock_irqsave(&tty->ctrl.lock, flags);
2228 if (tty->ctrl.pgrp) {
2229 pid = tty->ctrl.pgrp;
2230 type = PIDTYPE_PGID;
2231 } else {
2232 pid = task_pid(current);
2233 type = PIDTYPE_TGID;
2234 }
2235 get_pid(pid);
2236 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
2237 __f_setown(filp, pid, type, 0);
2238 put_pid(pid);
2239 retval = 0;
2240 }
2241out:
2242 return retval;
2243}
2244
2245static int tty_fasync(int fd, struct file *filp, int on)
2246{
2247 struct tty_struct *tty = file_tty(filp);
2248 int retval = -ENOTTY;
2249
2250 tty_lock(tty);
2251 if (!tty_hung_up_p(filp))
2252 retval = __tty_fasync(fd, filp, on);
2253 tty_unlock(tty);
2254
2255 return retval;
2256}
2257
2258static bool tty_legacy_tiocsti __read_mostly = IS_ENABLED(CONFIG_LEGACY_TIOCSTI);
2259/**
2260 * tiocsti - fake input character
2261 * @tty: tty to fake input into
2262 * @p: pointer to character
2263 *
2264 * Fake input to a tty device. Does the necessary locking and input management.
2265 *
2266 * FIXME: does not honour flow control ??
2267 *
2268 * Locking:
2269 * * Called functions take tty_ldiscs_lock
2270 * * current->signal->tty check is safe without locks
2271 */
2272static int tiocsti(struct tty_struct *tty, char __user *p)
2273{
2274 char ch, mbz = 0;
2275 struct tty_ldisc *ld;
2276
2277 if (!tty_legacy_tiocsti)
2278 return -EIO;
2279
2280 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2281 return -EPERM;
2282 if (get_user(ch, p))
2283 return -EFAULT;
2284 tty_audit_tiocsti(tty, ch);
2285 ld = tty_ldisc_ref_wait(tty);
2286 if (!ld)
2287 return -EIO;
2288 tty_buffer_lock_exclusive(tty->port);
2289 if (ld->ops->receive_buf)
2290 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2291 tty_buffer_unlock_exclusive(tty->port);
2292 tty_ldisc_deref(ld);
2293 return 0;
2294}
2295
2296/**
2297 * tiocgwinsz - implement window query ioctl
2298 * @tty: tty
2299 * @arg: user buffer for result
2300 *
2301 * Copies the kernel idea of the window size into the user buffer.
2302 *
2303 * Locking: @tty->winsize_mutex is taken to ensure the winsize data is
2304 * consistent.
2305 */
2306static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2307{
2308 int err;
2309
2310 mutex_lock(&tty->winsize_mutex);
2311 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2312 mutex_unlock(&tty->winsize_mutex);
2313
2314 return err ? -EFAULT : 0;
2315}
2316
2317/**
2318 * tty_do_resize - resize event
2319 * @tty: tty being resized
2320 * @ws: new dimensions
2321 *
2322 * Update the termios variables and send the necessary signals to peform a
2323 * terminal resize correctly.
2324 */
2325int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2326{
2327 struct pid *pgrp;
2328
2329 /* Lock the tty */
2330 mutex_lock(&tty->winsize_mutex);
2331 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2332 goto done;
2333
2334 /* Signal the foreground process group */
2335 pgrp = tty_get_pgrp(tty);
2336 if (pgrp)
2337 kill_pgrp(pgrp, SIGWINCH, 1);
2338 put_pid(pgrp);
2339
2340 tty->winsize = *ws;
2341done:
2342 mutex_unlock(&tty->winsize_mutex);
2343 return 0;
2344}
2345EXPORT_SYMBOL(tty_do_resize);
2346
2347/**
2348 * tiocswinsz - implement window size set ioctl
2349 * @tty: tty side of tty
2350 * @arg: user buffer for result
2351 *
2352 * Copies the user idea of the window size to the kernel. Traditionally this is
2353 * just advisory information but for the Linux console it actually has driver
2354 * level meaning and triggers a VC resize.
2355 *
2356 * Locking:
2357 * Driver dependent. The default do_resize method takes the tty termios
2358 * mutex and ctrl.lock. The console takes its own lock then calls into the
2359 * default method.
2360 */
2361static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2362{
2363 struct winsize tmp_ws;
2364
2365 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2366 return -EFAULT;
2367
2368 if (tty->ops->resize)
2369 return tty->ops->resize(tty, &tmp_ws);
2370 else
2371 return tty_do_resize(tty, &tmp_ws);
2372}
2373
2374/**
2375 * tioccons - allow admin to move logical console
2376 * @file: the file to become console
2377 *
2378 * Allow the administrator to move the redirected console device.
2379 *
2380 * Locking: uses redirect_lock to guard the redirect information
2381 */
2382static int tioccons(struct file *file)
2383{
2384 if (!capable(CAP_SYS_ADMIN))
2385 return -EPERM;
2386 if (file->f_op->write_iter == redirected_tty_write) {
2387 struct file *f;
2388
2389 spin_lock(&redirect_lock);
2390 f = redirect;
2391 redirect = NULL;
2392 spin_unlock(&redirect_lock);
2393 if (f)
2394 fput(f);
2395 return 0;
2396 }
2397 if (file->f_op->write_iter != tty_write)
2398 return -ENOTTY;
2399 if (!(file->f_mode & FMODE_WRITE))
2400 return -EBADF;
2401 if (!(file->f_mode & FMODE_CAN_WRITE))
2402 return -EINVAL;
2403 spin_lock(&redirect_lock);
2404 if (redirect) {
2405 spin_unlock(&redirect_lock);
2406 return -EBUSY;
2407 }
2408 redirect = get_file(file);
2409 spin_unlock(&redirect_lock);
2410 return 0;
2411}
2412
2413/**
2414 * tiocsetd - set line discipline
2415 * @tty: tty device
2416 * @p: pointer to user data
2417 *
2418 * Set the line discipline according to user request.
2419 *
2420 * Locking: see tty_set_ldisc(), this function is just a helper
2421 */
2422static int tiocsetd(struct tty_struct *tty, int __user *p)
2423{
2424 int disc;
2425 int ret;
2426
2427 if (get_user(disc, p))
2428 return -EFAULT;
2429
2430 ret = tty_set_ldisc(tty, disc);
2431
2432 return ret;
2433}
2434
2435/**
2436 * tiocgetd - get line discipline
2437 * @tty: tty device
2438 * @p: pointer to user data
2439 *
2440 * Retrieves the line discipline id directly from the ldisc.
2441 *
2442 * Locking: waits for ldisc reference (in case the line discipline is changing
2443 * or the @tty is being hungup)
2444 */
2445static int tiocgetd(struct tty_struct *tty, int __user *p)
2446{
2447 struct tty_ldisc *ld;
2448 int ret;
2449
2450 ld = tty_ldisc_ref_wait(tty);
2451 if (!ld)
2452 return -EIO;
2453 ret = put_user(ld->ops->num, p);
2454 tty_ldisc_deref(ld);
2455 return ret;
2456}
2457
2458/**
2459 * send_break - performed time break
2460 * @tty: device to break on
2461 * @duration: timeout in mS
2462 *
2463 * Perform a timed break on hardware that lacks its own driver level timed
2464 * break functionality.
2465 *
2466 * Locking:
2467 * @tty->atomic_write_lock serializes
2468 */
2469static int send_break(struct tty_struct *tty, unsigned int duration)
2470{
2471 int retval;
2472
2473 if (tty->ops->break_ctl == NULL)
2474 return 0;
2475
2476 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2477 retval = tty->ops->break_ctl(tty, duration);
2478 else {
2479 /* Do the work ourselves */
2480 if (tty_write_lock(tty, 0) < 0)
2481 return -EINTR;
2482 retval = tty->ops->break_ctl(tty, -1);
2483 if (retval)
2484 goto out;
2485 if (!signal_pending(current))
2486 msleep_interruptible(duration);
2487 retval = tty->ops->break_ctl(tty, 0);
2488out:
2489 tty_write_unlock(tty);
2490 if (signal_pending(current))
2491 retval = -EINTR;
2492 }
2493 return retval;
2494}
2495
2496/**
2497 * tty_tiocmget - get modem status
2498 * @tty: tty device
2499 * @p: pointer to result
2500 *
2501 * Obtain the modem status bits from the tty driver if the feature is
2502 * supported. Return -%ENOTTY if it is not available.
2503 *
2504 * Locking: none (up to the driver)
2505 */
2506static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2507{
2508 int retval = -ENOTTY;
2509
2510 if (tty->ops->tiocmget) {
2511 retval = tty->ops->tiocmget(tty);
2512
2513 if (retval >= 0)
2514 retval = put_user(retval, p);
2515 }
2516 return retval;
2517}
2518
2519/**
2520 * tty_tiocmset - set modem status
2521 * @tty: tty device
2522 * @cmd: command - clear bits, set bits or set all
2523 * @p: pointer to desired bits
2524 *
2525 * Set the modem status bits from the tty driver if the feature
2526 * is supported. Return -%ENOTTY if it is not available.
2527 *
2528 * Locking: none (up to the driver)
2529 */
2530static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2531 unsigned __user *p)
2532{
2533 int retval;
2534 unsigned int set, clear, val;
2535
2536 if (tty->ops->tiocmset == NULL)
2537 return -ENOTTY;
2538
2539 retval = get_user(val, p);
2540 if (retval)
2541 return retval;
2542 set = clear = 0;
2543 switch (cmd) {
2544 case TIOCMBIS:
2545 set = val;
2546 break;
2547 case TIOCMBIC:
2548 clear = val;
2549 break;
2550 case TIOCMSET:
2551 set = val;
2552 clear = ~val;
2553 break;
2554 }
2555 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2556 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2557 return tty->ops->tiocmset(tty, set, clear);
2558}
2559
2560/**
2561 * tty_get_icount - get tty statistics
2562 * @tty: tty device
2563 * @icount: output parameter
2564 *
2565 * Gets a copy of the @tty's icount statistics.
2566 *
2567 * Locking: none (up to the driver)
2568 */
2569int tty_get_icount(struct tty_struct *tty,
2570 struct serial_icounter_struct *icount)
2571{
2572 memset(icount, 0, sizeof(*icount));
2573
2574 if (tty->ops->get_icount)
2575 return tty->ops->get_icount(tty, icount);
2576 else
2577 return -ENOTTY;
2578}
2579EXPORT_SYMBOL_GPL(tty_get_icount);
2580
2581static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2582{
2583 struct serial_icounter_struct icount;
2584 int retval;
2585
2586 retval = tty_get_icount(tty, &icount);
2587 if (retval != 0)
2588 return retval;
2589
2590 if (copy_to_user(arg, &icount, sizeof(icount)))
2591 return -EFAULT;
2592 return 0;
2593}
2594
2595static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss)
2596{
2597 char comm[TASK_COMM_LEN];
2598 int flags;
2599
2600 flags = ss->flags & ASYNC_DEPRECATED;
2601
2602 if (flags)
2603 pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2604 __func__, get_task_comm(comm, current), flags);
2605
2606 if (!tty->ops->set_serial)
2607 return -ENOTTY;
2608
2609 return tty->ops->set_serial(tty, ss);
2610}
2611
2612static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2613{
2614 struct serial_struct v;
2615
2616 if (copy_from_user(&v, ss, sizeof(*ss)))
2617 return -EFAULT;
2618
2619 return tty_set_serial(tty, &v);
2620}
2621
2622static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2623{
2624 struct serial_struct v;
2625 int err;
2626
2627 memset(&v, 0, sizeof(v));
2628 if (!tty->ops->get_serial)
2629 return -ENOTTY;
2630 err = tty->ops->get_serial(tty, &v);
2631 if (!err && copy_to_user(ss, &v, sizeof(v)))
2632 err = -EFAULT;
2633 return err;
2634}
2635
2636/*
2637 * if pty, return the slave side (real_tty)
2638 * otherwise, return self
2639 */
2640static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2641{
2642 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2643 tty->driver->subtype == PTY_TYPE_MASTER)
2644 tty = tty->link;
2645 return tty;
2646}
2647
2648/*
2649 * Split this up, as gcc can choke on it otherwise..
2650 */
2651long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2652{
2653 struct tty_struct *tty = file_tty(file);
2654 struct tty_struct *real_tty;
2655 void __user *p = (void __user *)arg;
2656 int retval;
2657 struct tty_ldisc *ld;
2658
2659 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2660 return -EINVAL;
2661
2662 real_tty = tty_pair_get_tty(tty);
2663
2664 /*
2665 * Factor out some common prep work
2666 */
2667 switch (cmd) {
2668 case TIOCSETD:
2669 case TIOCSBRK:
2670 case TIOCCBRK:
2671 case TCSBRK:
2672 case TCSBRKP:
2673 retval = tty_check_change(tty);
2674 if (retval)
2675 return retval;
2676 if (cmd != TIOCCBRK) {
2677 tty_wait_until_sent(tty, 0);
2678 if (signal_pending(current))
2679 return -EINTR;
2680 }
2681 break;
2682 }
2683
2684 /*
2685 * Now do the stuff.
2686 */
2687 switch (cmd) {
2688 case TIOCSTI:
2689 return tiocsti(tty, p);
2690 case TIOCGWINSZ:
2691 return tiocgwinsz(real_tty, p);
2692 case TIOCSWINSZ:
2693 return tiocswinsz(real_tty, p);
2694 case TIOCCONS:
2695 return real_tty != tty ? -EINVAL : tioccons(file);
2696 case TIOCEXCL:
2697 set_bit(TTY_EXCLUSIVE, &tty->flags);
2698 return 0;
2699 case TIOCNXCL:
2700 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2701 return 0;
2702 case TIOCGEXCL:
2703 {
2704 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2705
2706 return put_user(excl, (int __user *)p);
2707 }
2708 case TIOCGETD:
2709 return tiocgetd(tty, p);
2710 case TIOCSETD:
2711 return tiocsetd(tty, p);
2712 case TIOCVHANGUP:
2713 if (!capable(CAP_SYS_ADMIN))
2714 return -EPERM;
2715 tty_vhangup(tty);
2716 return 0;
2717 case TIOCGDEV:
2718 {
2719 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2720
2721 return put_user(ret, (unsigned int __user *)p);
2722 }
2723 /*
2724 * Break handling
2725 */
2726 case TIOCSBRK: /* Turn break on, unconditionally */
2727 if (tty->ops->break_ctl)
2728 return tty->ops->break_ctl(tty, -1);
2729 return 0;
2730 case TIOCCBRK: /* Turn break off, unconditionally */
2731 if (tty->ops->break_ctl)
2732 return tty->ops->break_ctl(tty, 0);
2733 return 0;
2734 case TCSBRK: /* SVID version: non-zero arg --> no break */
2735 /* non-zero arg means wait for all output data
2736 * to be sent (performed above) but don't send break.
2737 * This is used by the tcdrain() termios function.
2738 */
2739 if (!arg)
2740 return send_break(tty, 250);
2741 return 0;
2742 case TCSBRKP: /* support for POSIX tcsendbreak() */
2743 return send_break(tty, arg ? arg*100 : 250);
2744
2745 case TIOCMGET:
2746 return tty_tiocmget(tty, p);
2747 case TIOCMSET:
2748 case TIOCMBIC:
2749 case TIOCMBIS:
2750 return tty_tiocmset(tty, cmd, p);
2751 case TIOCGICOUNT:
2752 return tty_tiocgicount(tty, p);
2753 case TCFLSH:
2754 switch (arg) {
2755 case TCIFLUSH:
2756 case TCIOFLUSH:
2757 /* flush tty buffer and allow ldisc to process ioctl */
2758 tty_buffer_flush(tty, NULL);
2759 break;
2760 }
2761 break;
2762 case TIOCSSERIAL:
2763 return tty_tiocsserial(tty, p);
2764 case TIOCGSERIAL:
2765 return tty_tiocgserial(tty, p);
2766 case TIOCGPTPEER:
2767 /* Special because the struct file is needed */
2768 return ptm_open_peer(file, tty, (int)arg);
2769 default:
2770 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2771 if (retval != -ENOIOCTLCMD)
2772 return retval;
2773 }
2774 if (tty->ops->ioctl) {
2775 retval = tty->ops->ioctl(tty, cmd, arg);
2776 if (retval != -ENOIOCTLCMD)
2777 return retval;
2778 }
2779 ld = tty_ldisc_ref_wait(tty);
2780 if (!ld)
2781 return hung_up_tty_ioctl(file, cmd, arg);
2782 retval = -EINVAL;
2783 if (ld->ops->ioctl) {
2784 retval = ld->ops->ioctl(tty, cmd, arg);
2785 if (retval == -ENOIOCTLCMD)
2786 retval = -ENOTTY;
2787 }
2788 tty_ldisc_deref(ld);
2789 return retval;
2790}
2791
2792#ifdef CONFIG_COMPAT
2793
2794struct serial_struct32 {
2795 compat_int_t type;
2796 compat_int_t line;
2797 compat_uint_t port;
2798 compat_int_t irq;
2799 compat_int_t flags;
2800 compat_int_t xmit_fifo_size;
2801 compat_int_t custom_divisor;
2802 compat_int_t baud_base;
2803 unsigned short close_delay;
2804 char io_type;
2805 char reserved_char;
2806 compat_int_t hub6;
2807 unsigned short closing_wait; /* time to wait before closing */
2808 unsigned short closing_wait2; /* no longer used... */
2809 compat_uint_t iomem_base;
2810 unsigned short iomem_reg_shift;
2811 unsigned int port_high;
2812 /* compat_ulong_t iomap_base FIXME */
2813 compat_int_t reserved;
2814};
2815
2816static int compat_tty_tiocsserial(struct tty_struct *tty,
2817 struct serial_struct32 __user *ss)
2818{
2819 struct serial_struct32 v32;
2820 struct serial_struct v;
2821
2822 if (copy_from_user(&v32, ss, sizeof(*ss)))
2823 return -EFAULT;
2824
2825 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2826 v.iomem_base = compat_ptr(v32.iomem_base);
2827 v.iomem_reg_shift = v32.iomem_reg_shift;
2828 v.port_high = v32.port_high;
2829 v.iomap_base = 0;
2830
2831 return tty_set_serial(tty, &v);
2832}
2833
2834static int compat_tty_tiocgserial(struct tty_struct *tty,
2835 struct serial_struct32 __user *ss)
2836{
2837 struct serial_struct32 v32;
2838 struct serial_struct v;
2839 int err;
2840
2841 memset(&v, 0, sizeof(v));
2842 memset(&v32, 0, sizeof(v32));
2843
2844 if (!tty->ops->get_serial)
2845 return -ENOTTY;
2846 err = tty->ops->get_serial(tty, &v);
2847 if (!err) {
2848 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2849 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2850 0xfffffff : ptr_to_compat(v.iomem_base);
2851 v32.iomem_reg_shift = v.iomem_reg_shift;
2852 v32.port_high = v.port_high;
2853 if (copy_to_user(ss, &v32, sizeof(v32)))
2854 err = -EFAULT;
2855 }
2856 return err;
2857}
2858static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2859 unsigned long arg)
2860{
2861 struct tty_struct *tty = file_tty(file);
2862 struct tty_ldisc *ld;
2863 int retval = -ENOIOCTLCMD;
2864
2865 switch (cmd) {
2866 case TIOCOUTQ:
2867 case TIOCSTI:
2868 case TIOCGWINSZ:
2869 case TIOCSWINSZ:
2870 case TIOCGEXCL:
2871 case TIOCGETD:
2872 case TIOCSETD:
2873 case TIOCGDEV:
2874 case TIOCMGET:
2875 case TIOCMSET:
2876 case TIOCMBIC:
2877 case TIOCMBIS:
2878 case TIOCGICOUNT:
2879 case TIOCGPGRP:
2880 case TIOCSPGRP:
2881 case TIOCGSID:
2882 case TIOCSERGETLSR:
2883 case TIOCGRS485:
2884 case TIOCSRS485:
2885#ifdef TIOCGETP
2886 case TIOCGETP:
2887 case TIOCSETP:
2888 case TIOCSETN:
2889#endif
2890#ifdef TIOCGETC
2891 case TIOCGETC:
2892 case TIOCSETC:
2893#endif
2894#ifdef TIOCGLTC
2895 case TIOCGLTC:
2896 case TIOCSLTC:
2897#endif
2898 case TCSETSF:
2899 case TCSETSW:
2900 case TCSETS:
2901 case TCGETS:
2902#ifdef TCGETS2
2903 case TCGETS2:
2904 case TCSETSF2:
2905 case TCSETSW2:
2906 case TCSETS2:
2907#endif
2908 case TCGETA:
2909 case TCSETAF:
2910 case TCSETAW:
2911 case TCSETA:
2912 case TIOCGLCKTRMIOS:
2913 case TIOCSLCKTRMIOS:
2914#ifdef TCGETX
2915 case TCGETX:
2916 case TCSETX:
2917 case TCSETXW:
2918 case TCSETXF:
2919#endif
2920 case TIOCGSOFTCAR:
2921 case TIOCSSOFTCAR:
2922
2923 case PPPIOCGCHAN:
2924 case PPPIOCGUNIT:
2925 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2926 case TIOCCONS:
2927 case TIOCEXCL:
2928 case TIOCNXCL:
2929 case TIOCVHANGUP:
2930 case TIOCSBRK:
2931 case TIOCCBRK:
2932 case TCSBRK:
2933 case TCSBRKP:
2934 case TCFLSH:
2935 case TIOCGPTPEER:
2936 case TIOCNOTTY:
2937 case TIOCSCTTY:
2938 case TCXONC:
2939 case TIOCMIWAIT:
2940 case TIOCSERCONFIG:
2941 return tty_ioctl(file, cmd, arg);
2942 }
2943
2944 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2945 return -EINVAL;
2946
2947 switch (cmd) {
2948 case TIOCSSERIAL:
2949 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2950 case TIOCGSERIAL:
2951 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2952 }
2953 if (tty->ops->compat_ioctl) {
2954 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2955 if (retval != -ENOIOCTLCMD)
2956 return retval;
2957 }
2958
2959 ld = tty_ldisc_ref_wait(tty);
2960 if (!ld)
2961 return hung_up_tty_compat_ioctl(file, cmd, arg);
2962 if (ld->ops->compat_ioctl)
2963 retval = ld->ops->compat_ioctl(tty, cmd, arg);
2964 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2965 retval = ld->ops->ioctl(tty, (unsigned long)compat_ptr(cmd),
2966 arg);
2967 tty_ldisc_deref(ld);
2968
2969 return retval;
2970}
2971#endif
2972
2973static int this_tty(const void *t, struct file *file, unsigned fd)
2974{
2975 if (likely(file->f_op->read_iter != tty_read))
2976 return 0;
2977 return file_tty(file) != t ? 0 : fd + 1;
2978}
2979
2980/*
2981 * This implements the "Secure Attention Key" --- the idea is to
2982 * prevent trojan horses by killing all processes associated with this
2983 * tty when the user hits the "Secure Attention Key". Required for
2984 * super-paranoid applications --- see the Orange Book for more details.
2985 *
2986 * This code could be nicer; ideally it should send a HUP, wait a few
2987 * seconds, then send a INT, and then a KILL signal. But you then
2988 * have to coordinate with the init process, since all processes associated
2989 * with the current tty must be dead before the new getty is allowed
2990 * to spawn.
2991 *
2992 * Now, if it would be correct ;-/ The current code has a nasty hole -
2993 * it doesn't catch files in flight. We may send the descriptor to ourselves
2994 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2995 *
2996 * Nasty bug: do_SAK is being called in interrupt context. This can
2997 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2998 */
2999void __do_SAK(struct tty_struct *tty)
3000{
3001 struct task_struct *g, *p;
3002 struct pid *session;
3003 int i;
3004 unsigned long flags;
3005
3006 spin_lock_irqsave(&tty->ctrl.lock, flags);
3007 session = get_pid(tty->ctrl.session);
3008 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
3009
3010 tty_ldisc_flush(tty);
3011
3012 tty_driver_flush_buffer(tty);
3013
3014 read_lock(&tasklist_lock);
3015 /* Kill the entire session */
3016 do_each_pid_task(session, PIDTYPE_SID, p) {
3017 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3018 task_pid_nr(p), p->comm);
3019 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3020 } while_each_pid_task(session, PIDTYPE_SID, p);
3021
3022 /* Now kill any processes that happen to have the tty open */
3023 do_each_thread(g, p) {
3024 if (p->signal->tty == tty) {
3025 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3026 task_pid_nr(p), p->comm);
3027 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
3028 PIDTYPE_SID);
3029 continue;
3030 }
3031 task_lock(p);
3032 i = iterate_fd(p->files, 0, this_tty, tty);
3033 if (i != 0) {
3034 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3035 task_pid_nr(p), p->comm, i - 1);
3036 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
3037 PIDTYPE_SID);
3038 }
3039 task_unlock(p);
3040 } while_each_thread(g, p);
3041 read_unlock(&tasklist_lock);
3042 put_pid(session);
3043}
3044
3045static void do_SAK_work(struct work_struct *work)
3046{
3047 struct tty_struct *tty =
3048 container_of(work, struct tty_struct, SAK_work);
3049 __do_SAK(tty);
3050}
3051
3052/*
3053 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3054 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3055 * the values which we write to it will be identical to the values which it
3056 * already has. --akpm
3057 */
3058void do_SAK(struct tty_struct *tty)
3059{
3060 if (!tty)
3061 return;
3062 schedule_work(&tty->SAK_work);
3063}
3064EXPORT_SYMBOL(do_SAK);
3065
3066/* Must put_device() after it's unused! */
3067static struct device *tty_get_device(struct tty_struct *tty)
3068{
3069 dev_t devt = tty_devnum(tty);
3070
3071 return class_find_device_by_devt(tty_class, devt);
3072}
3073
3074
3075/**
3076 * alloc_tty_struct - allocate a new tty
3077 * @driver: driver which will handle the returned tty
3078 * @idx: minor of the tty
3079 *
3080 * This subroutine allocates and initializes a tty structure.
3081 *
3082 * Locking: none - @tty in question is not exposed at this point
3083 */
3084struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3085{
3086 struct tty_struct *tty;
3087
3088 tty = kzalloc(sizeof(*tty), GFP_KERNEL_ACCOUNT);
3089 if (!tty)
3090 return NULL;
3091
3092 kref_init(&tty->kref);
3093 if (tty_ldisc_init(tty)) {
3094 kfree(tty);
3095 return NULL;
3096 }
3097 tty->ctrl.session = NULL;
3098 tty->ctrl.pgrp = NULL;
3099 mutex_init(&tty->legacy_mutex);
3100 mutex_init(&tty->throttle_mutex);
3101 init_rwsem(&tty->termios_rwsem);
3102 mutex_init(&tty->winsize_mutex);
3103 init_ldsem(&tty->ldisc_sem);
3104 init_waitqueue_head(&tty->write_wait);
3105 init_waitqueue_head(&tty->read_wait);
3106 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3107 mutex_init(&tty->atomic_write_lock);
3108 spin_lock_init(&tty->ctrl.lock);
3109 spin_lock_init(&tty->flow.lock);
3110 spin_lock_init(&tty->files_lock);
3111 INIT_LIST_HEAD(&tty->tty_files);
3112 INIT_WORK(&tty->SAK_work, do_SAK_work);
3113
3114 tty->driver = driver;
3115 tty->ops = driver->ops;
3116 tty->index = idx;
3117 tty_line_name(driver, idx, tty->name);
3118 tty->dev = tty_get_device(tty);
3119
3120 return tty;
3121}
3122
3123/**
3124 * tty_put_char - write one character to a tty
3125 * @tty: tty
3126 * @ch: character to write
3127 *
3128 * Write one byte to the @tty using the provided @tty->ops->put_char() method
3129 * if present.
3130 *
3131 * Note: the specific put_char operation in the driver layer may go
3132 * away soon. Don't call it directly, use this method
3133 *
3134 * Return: the number of characters successfully output.
3135 */
3136int tty_put_char(struct tty_struct *tty, unsigned char ch)
3137{
3138 if (tty->ops->put_char)
3139 return tty->ops->put_char(tty, ch);
3140 return tty->ops->write(tty, &ch, 1);
3141}
3142EXPORT_SYMBOL_GPL(tty_put_char);
3143
3144struct class *tty_class;
3145
3146static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3147 unsigned int index, unsigned int count)
3148{
3149 int err;
3150
3151 /* init here, since reused cdevs cause crashes */
3152 driver->cdevs[index] = cdev_alloc();
3153 if (!driver->cdevs[index])
3154 return -ENOMEM;
3155 driver->cdevs[index]->ops = &tty_fops;
3156 driver->cdevs[index]->owner = driver->owner;
3157 err = cdev_add(driver->cdevs[index], dev, count);
3158 if (err)
3159 kobject_put(&driver->cdevs[index]->kobj);
3160 return err;
3161}
3162
3163/**
3164 * tty_register_device - register a tty device
3165 * @driver: the tty driver that describes the tty device
3166 * @index: the index in the tty driver for this tty device
3167 * @device: a struct device that is associated with this tty device.
3168 * This field is optional, if there is no known struct device
3169 * for this tty device it can be set to NULL safely.
3170 *
3171 * This call is required to be made to register an individual tty device
3172 * if the tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If
3173 * that bit is not set, this function should not be called by a tty
3174 * driver.
3175 *
3176 * Locking: ??
3177 *
3178 * Return: A pointer to the struct device for this tty device (or
3179 * ERR_PTR(-EFOO) on error).
3180 */
3181struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3182 struct device *device)
3183{
3184 return tty_register_device_attr(driver, index, device, NULL, NULL);
3185}
3186EXPORT_SYMBOL(tty_register_device);
3187
3188static void tty_device_create_release(struct device *dev)
3189{
3190 dev_dbg(dev, "releasing...\n");
3191 kfree(dev);
3192}
3193
3194/**
3195 * tty_register_device_attr - register a tty device
3196 * @driver: the tty driver that describes the tty device
3197 * @index: the index in the tty driver for this tty device
3198 * @device: a struct device that is associated with this tty device.
3199 * This field is optional, if there is no known struct device
3200 * for this tty device it can be set to %NULL safely.
3201 * @drvdata: Driver data to be set to device.
3202 * @attr_grp: Attribute group to be set on device.
3203 *
3204 * This call is required to be made to register an individual tty device if the
3205 * tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If that bit is
3206 * not set, this function should not be called by a tty driver.
3207 *
3208 * Locking: ??
3209 *
3210 * Return: A pointer to the struct device for this tty device (or
3211 * ERR_PTR(-EFOO) on error).
3212 */
3213struct device *tty_register_device_attr(struct tty_driver *driver,
3214 unsigned index, struct device *device,
3215 void *drvdata,
3216 const struct attribute_group **attr_grp)
3217{
3218 char name[64];
3219 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3220 struct ktermios *tp;
3221 struct device *dev;
3222 int retval;
3223
3224 if (index >= driver->num) {
3225 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3226 driver->name, index);
3227 return ERR_PTR(-EINVAL);
3228 }
3229
3230 if (driver->type == TTY_DRIVER_TYPE_PTY)
3231 pty_line_name(driver, index, name);
3232 else
3233 tty_line_name(driver, index, name);
3234
3235 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3236 if (!dev)
3237 return ERR_PTR(-ENOMEM);
3238
3239 dev->devt = devt;
3240 dev->class = tty_class;
3241 dev->parent = device;
3242 dev->release = tty_device_create_release;
3243 dev_set_name(dev, "%s", name);
3244 dev->groups = attr_grp;
3245 dev_set_drvdata(dev, drvdata);
3246
3247 dev_set_uevent_suppress(dev, 1);
3248
3249 retval = device_register(dev);
3250 if (retval)
3251 goto err_put;
3252
3253 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3254 /*
3255 * Free any saved termios data so that the termios state is
3256 * reset when reusing a minor number.
3257 */
3258 tp = driver->termios[index];
3259 if (tp) {
3260 driver->termios[index] = NULL;
3261 kfree(tp);
3262 }
3263
3264 retval = tty_cdev_add(driver, devt, index, 1);
3265 if (retval)
3266 goto err_del;
3267 }
3268
3269 dev_set_uevent_suppress(dev, 0);
3270 kobject_uevent(&dev->kobj, KOBJ_ADD);
3271
3272 return dev;
3273
3274err_del:
3275 device_del(dev);
3276err_put:
3277 put_device(dev);
3278
3279 return ERR_PTR(retval);
3280}
3281EXPORT_SYMBOL_GPL(tty_register_device_attr);
3282
3283/**
3284 * tty_unregister_device - unregister a tty device
3285 * @driver: the tty driver that describes the tty device
3286 * @index: the index in the tty driver for this tty device
3287 *
3288 * If a tty device is registered with a call to tty_register_device() then
3289 * this function must be called when the tty device is gone.
3290 *
3291 * Locking: ??
3292 */
3293void tty_unregister_device(struct tty_driver *driver, unsigned index)
3294{
3295 device_destroy(tty_class,
3296 MKDEV(driver->major, driver->minor_start) + index);
3297 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3298 cdev_del(driver->cdevs[index]);
3299 driver->cdevs[index] = NULL;
3300 }
3301}
3302EXPORT_SYMBOL(tty_unregister_device);
3303
3304/**
3305 * __tty_alloc_driver -- allocate tty driver
3306 * @lines: count of lines this driver can handle at most
3307 * @owner: module which is responsible for this driver
3308 * @flags: some of %TTY_DRIVER_ flags, will be set in driver->flags
3309 *
3310 * This should not be called directly, some of the provided macros should be
3311 * used instead. Use IS_ERR() and friends on @retval.
3312 */
3313struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3314 unsigned long flags)
3315{
3316 struct tty_driver *driver;
3317 unsigned int cdevs = 1;
3318 int err;
3319
3320 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3321 return ERR_PTR(-EINVAL);
3322
3323 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
3324 if (!driver)
3325 return ERR_PTR(-ENOMEM);
3326
3327 kref_init(&driver->kref);
3328 driver->num = lines;
3329 driver->owner = owner;
3330 driver->flags = flags;
3331
3332 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3333 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3334 GFP_KERNEL);
3335 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3336 GFP_KERNEL);
3337 if (!driver->ttys || !driver->termios) {
3338 err = -ENOMEM;
3339 goto err_free_all;
3340 }
3341 }
3342
3343 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3344 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3345 GFP_KERNEL);
3346 if (!driver->ports) {
3347 err = -ENOMEM;
3348 goto err_free_all;
3349 }
3350 cdevs = lines;
3351 }
3352
3353 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3354 if (!driver->cdevs) {
3355 err = -ENOMEM;
3356 goto err_free_all;
3357 }
3358
3359 return driver;
3360err_free_all:
3361 kfree(driver->ports);
3362 kfree(driver->ttys);
3363 kfree(driver->termios);
3364 kfree(driver->cdevs);
3365 kfree(driver);
3366 return ERR_PTR(err);
3367}
3368EXPORT_SYMBOL(__tty_alloc_driver);
3369
3370static void destruct_tty_driver(struct kref *kref)
3371{
3372 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3373 int i;
3374 struct ktermios *tp;
3375
3376 if (driver->flags & TTY_DRIVER_INSTALLED) {
3377 for (i = 0; i < driver->num; i++) {
3378 tp = driver->termios[i];
3379 if (tp) {
3380 driver->termios[i] = NULL;
3381 kfree(tp);
3382 }
3383 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3384 tty_unregister_device(driver, i);
3385 }
3386 proc_tty_unregister_driver(driver);
3387 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3388 cdev_del(driver->cdevs[0]);
3389 }
3390 kfree(driver->cdevs);
3391 kfree(driver->ports);
3392 kfree(driver->termios);
3393 kfree(driver->ttys);
3394 kfree(driver);
3395}
3396
3397/**
3398 * tty_driver_kref_put -- drop a reference to a tty driver
3399 * @driver: driver of which to drop the reference
3400 *
3401 * The final put will destroy and free up the driver.
3402 */
3403void tty_driver_kref_put(struct tty_driver *driver)
3404{
3405 kref_put(&driver->kref, destruct_tty_driver);
3406}
3407EXPORT_SYMBOL(tty_driver_kref_put);
3408
3409/**
3410 * tty_register_driver -- register a tty driver
3411 * @driver: driver to register
3412 *
3413 * Called by a tty driver to register itself.
3414 */
3415int tty_register_driver(struct tty_driver *driver)
3416{
3417 int error;
3418 int i;
3419 dev_t dev;
3420 struct device *d;
3421
3422 if (!driver->major) {
3423 error = alloc_chrdev_region(&dev, driver->minor_start,
3424 driver->num, driver->name);
3425 if (!error) {
3426 driver->major = MAJOR(dev);
3427 driver->minor_start = MINOR(dev);
3428 }
3429 } else {
3430 dev = MKDEV(driver->major, driver->minor_start);
3431 error = register_chrdev_region(dev, driver->num, driver->name);
3432 }
3433 if (error < 0)
3434 goto err;
3435
3436 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3437 error = tty_cdev_add(driver, dev, 0, driver->num);
3438 if (error)
3439 goto err_unreg_char;
3440 }
3441
3442 mutex_lock(&tty_mutex);
3443 list_add(&driver->tty_drivers, &tty_drivers);
3444 mutex_unlock(&tty_mutex);
3445
3446 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3447 for (i = 0; i < driver->num; i++) {
3448 d = tty_register_device(driver, i, NULL);
3449 if (IS_ERR(d)) {
3450 error = PTR_ERR(d);
3451 goto err_unreg_devs;
3452 }
3453 }
3454 }
3455 proc_tty_register_driver(driver);
3456 driver->flags |= TTY_DRIVER_INSTALLED;
3457 return 0;
3458
3459err_unreg_devs:
3460 for (i--; i >= 0; i--)
3461 tty_unregister_device(driver, i);
3462
3463 mutex_lock(&tty_mutex);
3464 list_del(&driver->tty_drivers);
3465 mutex_unlock(&tty_mutex);
3466
3467err_unreg_char:
3468 unregister_chrdev_region(dev, driver->num);
3469err:
3470 return error;
3471}
3472EXPORT_SYMBOL(tty_register_driver);
3473
3474/**
3475 * tty_unregister_driver -- unregister a tty driver
3476 * @driver: driver to unregister
3477 *
3478 * Called by a tty driver to unregister itself.
3479 */
3480void tty_unregister_driver(struct tty_driver *driver)
3481{
3482 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3483 driver->num);
3484 mutex_lock(&tty_mutex);
3485 list_del(&driver->tty_drivers);
3486 mutex_unlock(&tty_mutex);
3487}
3488EXPORT_SYMBOL(tty_unregister_driver);
3489
3490dev_t tty_devnum(struct tty_struct *tty)
3491{
3492 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3493}
3494EXPORT_SYMBOL(tty_devnum);
3495
3496void tty_default_fops(struct file_operations *fops)
3497{
3498 *fops = tty_fops;
3499}
3500
3501static char *tty_devnode(const struct device *dev, umode_t *mode)
3502{
3503 if (!mode)
3504 return NULL;
3505 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3506 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3507 *mode = 0666;
3508 return NULL;
3509}
3510
3511static int __init tty_class_init(void)
3512{
3513 tty_class = class_create(THIS_MODULE, "tty");
3514 if (IS_ERR(tty_class))
3515 return PTR_ERR(tty_class);
3516 tty_class->devnode = tty_devnode;
3517 return 0;
3518}
3519
3520postcore_initcall(tty_class_init);
3521
3522/* 3/2004 jmc: why do these devices exist? */
3523static struct cdev tty_cdev, console_cdev;
3524
3525static ssize_t show_cons_active(struct device *dev,
3526 struct device_attribute *attr, char *buf)
3527{
3528 struct console *cs[16];
3529 int i = 0;
3530 struct console *c;
3531 ssize_t count = 0;
3532
3533 /*
3534 * Hold the console_list_lock to guarantee that no consoles are
3535 * unregistered until all console processing is complete.
3536 * This also allows safe traversal of the console list and
3537 * race-free reading of @flags.
3538 */
3539 console_list_lock();
3540
3541 for_each_console(c) {
3542 if (!c->device)
3543 continue;
3544 if (!c->write)
3545 continue;
3546 if ((c->flags & CON_ENABLED) == 0)
3547 continue;
3548 cs[i++] = c;
3549 if (i >= ARRAY_SIZE(cs))
3550 break;
3551 }
3552
3553 /*
3554 * Take console_lock to serialize device() callback with
3555 * other console operations. For example, fg_console is
3556 * modified under console_lock when switching vt.
3557 */
3558 console_lock();
3559 while (i--) {
3560 int index = cs[i]->index;
3561 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3562
3563 /* don't resolve tty0 as some programs depend on it */
3564 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3565 count += tty_line_name(drv, index, buf + count);
3566 else
3567 count += sprintf(buf + count, "%s%d",
3568 cs[i]->name, cs[i]->index);
3569
3570 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3571 }
3572 console_unlock();
3573
3574 console_list_unlock();
3575
3576 return count;
3577}
3578static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3579
3580static struct attribute *cons_dev_attrs[] = {
3581 &dev_attr_active.attr,
3582 NULL
3583};
3584
3585ATTRIBUTE_GROUPS(cons_dev);
3586
3587static struct device *consdev;
3588
3589void console_sysfs_notify(void)
3590{
3591 if (consdev)
3592 sysfs_notify(&consdev->kobj, NULL, "active");
3593}
3594
3595static struct ctl_table tty_table[] = {
3596 {
3597 .procname = "legacy_tiocsti",
3598 .data = &tty_legacy_tiocsti,
3599 .maxlen = sizeof(tty_legacy_tiocsti),
3600 .mode = 0644,
3601 .proc_handler = proc_dobool,
3602 },
3603 {
3604 .procname = "ldisc_autoload",
3605 .data = &tty_ldisc_autoload,
3606 .maxlen = sizeof(tty_ldisc_autoload),
3607 .mode = 0644,
3608 .proc_handler = proc_dointvec,
3609 .extra1 = SYSCTL_ZERO,
3610 .extra2 = SYSCTL_ONE,
3611 },
3612 { }
3613};
3614
3615static struct ctl_table tty_dir_table[] = {
3616 {
3617 .procname = "tty",
3618 .mode = 0555,
3619 .child = tty_table,
3620 },
3621 { }
3622};
3623
3624static struct ctl_table tty_root_table[] = {
3625 {
3626 .procname = "dev",
3627 .mode = 0555,
3628 .child = tty_dir_table,
3629 },
3630 { }
3631};
3632
3633/*
3634 * Ok, now we can initialize the rest of the tty devices and can count
3635 * on memory allocations, interrupts etc..
3636 */
3637int __init tty_init(void)
3638{
3639 register_sysctl_table(tty_root_table);
3640 cdev_init(&tty_cdev, &tty_fops);
3641 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3642 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3643 panic("Couldn't register /dev/tty driver\n");
3644 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3645
3646 cdev_init(&console_cdev, &console_fops);
3647 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3648 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3649 panic("Couldn't register /dev/console driver\n");
3650 consdev = device_create_with_groups(tty_class, NULL,
3651 MKDEV(TTYAUX_MAJOR, 1), NULL,
3652 cons_dev_groups, "console");
3653 if (IS_ERR(consdev))
3654 consdev = NULL;
3655
3656#ifdef CONFIG_VT
3657 vty_init(&console_fops);
3658#endif
3659 return 0;
3660}
1// 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
103#include <linux/uaccess.h>
104
105#include <linux/kbd_kern.h>
106#include <linux/vt_kern.h>
107#include <linux/selection.h>
108
109#include <linux/kmod.h>
110#include <linux/nsproxy.h>
111#include "tty.h"
112
113#undef TTY_DEBUG_HANGUP
114#ifdef TTY_DEBUG_HANGUP
115# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
116#else
117# define tty_debug_hangup(tty, f, args...) do { } while (0)
118#endif
119
120#define TTY_PARANOIA_CHECK 1
121#define CHECK_TTY_COUNT 1
122
123struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
124 .c_iflag = ICRNL | IXON,
125 .c_oflag = OPOST | ONLCR,
126 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
127 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
128 ECHOCTL | ECHOKE | IEXTEN,
129 .c_cc = INIT_C_CC,
130 .c_ispeed = 38400,
131 .c_ospeed = 38400,
132 /* .c_line = N_TTY, */
133};
134EXPORT_SYMBOL(tty_std_termios);
135
136/* This list gets poked at by procfs and various bits of boot up code. This
137 * could do with some rationalisation such as pulling the tty proc function
138 * into this file.
139 */
140
141LIST_HEAD(tty_drivers); /* linked list of tty drivers */
142
143/* Mutex to protect creating and releasing a tty */
144DEFINE_MUTEX(tty_mutex);
145
146static ssize_t tty_read(struct kiocb *, struct iov_iter *);
147static ssize_t tty_write(struct kiocb *, struct iov_iter *);
148static __poll_t tty_poll(struct file *, poll_table *);
149static int tty_open(struct inode *, struct file *);
150#ifdef CONFIG_COMPAT
151static long tty_compat_ioctl(struct file *file, unsigned int cmd,
152 unsigned long arg);
153#else
154#define tty_compat_ioctl NULL
155#endif
156static int __tty_fasync(int fd, struct file *filp, int on);
157static int tty_fasync(int fd, struct file *filp, int on);
158static void release_tty(struct tty_struct *tty, int idx);
159
160/**
161 * free_tty_struct - free a disused tty
162 * @tty: tty struct to free
163 *
164 * Free the write buffers, tty queue and tty memory itself.
165 *
166 * Locking: none. Must be called after tty is definitely unused
167 */
168
169static void free_tty_struct(struct tty_struct *tty)
170{
171 tty_ldisc_deinit(tty);
172 put_device(tty->dev);
173 kfree(tty->write_buf);
174 tty->magic = 0xDEADDEAD;
175 kfree(tty);
176}
177
178static inline struct tty_struct *file_tty(struct file *file)
179{
180 return ((struct tty_file_private *)file->private_data)->tty;
181}
182
183int tty_alloc_file(struct file *file)
184{
185 struct tty_file_private *priv;
186
187 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
188 if (!priv)
189 return -ENOMEM;
190
191 file->private_data = priv;
192
193 return 0;
194}
195
196/* Associate a new file with the tty structure */
197void tty_add_file(struct tty_struct *tty, struct file *file)
198{
199 struct tty_file_private *priv = file->private_data;
200
201 priv->tty = tty;
202 priv->file = file;
203
204 spin_lock(&tty->files_lock);
205 list_add(&priv->list, &tty->tty_files);
206 spin_unlock(&tty->files_lock);
207}
208
209/*
210 * tty_free_file - free file->private_data
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
240 * naming policy and if udev is in use may not reflect user space
241 *
242 * Locking: none
243 */
244
245const char *tty_name(const struct tty_struct *tty)
246{
247 if (!tty) /* Hmm. NULL pointer. That's fun. */
248 return "NULL tty";
249 return tty->name;
250}
251EXPORT_SYMBOL(tty_name);
252
253const char *tty_driver_name(const struct tty_struct *tty)
254{
255 if (!tty || !tty->driver)
256 return "";
257 return tty->driver->name;
258}
259
260static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
261 const char *routine)
262{
263#ifdef TTY_PARANOIA_CHECK
264 if (!tty) {
265 pr_warn("(%d:%d): %s: NULL tty\n",
266 imajor(inode), iminor(inode), routine);
267 return 1;
268 }
269 if (tty->magic != TTY_MAGIC) {
270 pr_warn("(%d:%d): %s: bad magic number\n",
271 imajor(inode), iminor(inode), routine);
272 return 1;
273 }
274#endif
275 return 0;
276}
277
278/* Caller must hold tty_lock */
279static int check_tty_count(struct tty_struct *tty, const char *routine)
280{
281#ifdef CHECK_TTY_COUNT
282 struct list_head *p;
283 int count = 0, kopen_count = 0;
284
285 spin_lock(&tty->files_lock);
286 list_for_each(p, &tty->tty_files) {
287 count++;
288 }
289 spin_unlock(&tty->files_lock);
290 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
291 tty->driver->subtype == PTY_TYPE_SLAVE &&
292 tty->link && tty->link->count)
293 count++;
294 if (tty_port_kopened(tty->port))
295 kopen_count++;
296 if (tty->count != (count + kopen_count)) {
297 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
298 routine, tty->count, count, kopen_count);
299 return (count + kopen_count);
300 }
301#endif
302 return 0;
303}
304
305/**
306 * get_tty_driver - find device of a tty
307 * @device: 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
323 if (device < base || device >= base + p->num)
324 continue;
325 *index = device - base;
326 return tty_driver_kref_get(p);
327 }
328 return NULL;
329}
330
331/**
332 * tty_dev_name_to_number - return dev_t for device name
333 * @name: user space name of device under /dev
334 * @number: pointer to dev_t that this function will populate
335 *
336 * This function converts device names like ttyS0 or ttyUSB1 into dev_t
337 * like (4, 64) or (188, 1). If no corresponding driver is registered then
338 * the function returns -ENODEV.
339 *
340 * Locking: this acquires tty_mutex to protect the tty_drivers list from
341 * being modified while we are traversing it, and makes sure to
342 * release it before exiting.
343 */
344int tty_dev_name_to_number(const char *name, dev_t *number)
345{
346 struct tty_driver *p;
347 int ret;
348 int index, prefix_length = 0;
349 const char *str;
350
351 for (str = name; *str && !isdigit(*str); str++)
352 ;
353
354 if (!*str)
355 return -EINVAL;
356
357 ret = kstrtoint(str, 10, &index);
358 if (ret)
359 return ret;
360
361 prefix_length = str - name;
362 mutex_lock(&tty_mutex);
363
364 list_for_each_entry(p, &tty_drivers, tty_drivers)
365 if (prefix_length == strlen(p->name) && strncmp(name,
366 p->name, prefix_length) == 0) {
367 if (index < p->num) {
368 *number = MKDEV(p->major, p->minor_start + index);
369 goto out;
370 }
371 }
372
373 /* if here then driver wasn't found */
374 ret = -ENODEV;
375out:
376 mutex_unlock(&tty_mutex);
377 return ret;
378}
379EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
380
381#ifdef CONFIG_CONSOLE_POLL
382
383/**
384 * tty_find_polling_driver - find device of a polled tty
385 * @name: name string to match
386 * @line: pointer to resulting tty line nr
387 *
388 * This routine returns a tty driver structure, given a name
389 * and the condition that the tty driver is capable of polled
390 * operation.
391 */
392struct tty_driver *tty_find_polling_driver(char *name, int *line)
393{
394 struct tty_driver *p, *res = NULL;
395 int tty_line = 0;
396 int len;
397 char *str, *stp;
398
399 for (str = name; *str; str++)
400 if ((*str >= '0' && *str <= '9') || *str == ',')
401 break;
402 if (!*str)
403 return NULL;
404
405 len = str - name;
406 tty_line = simple_strtoul(str, &str, 10);
407
408 mutex_lock(&tty_mutex);
409 /* Search through the tty devices to look for a match */
410 list_for_each_entry(p, &tty_drivers, tty_drivers) {
411 if (!len || strncmp(name, p->name, len) != 0)
412 continue;
413 stp = str;
414 if (*stp == ',')
415 stp++;
416 if (*stp == '\0')
417 stp = NULL;
418
419 if (tty_line >= 0 && tty_line < p->num && p->ops &&
420 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
421 res = tty_driver_kref_get(p);
422 *line = tty_line;
423 break;
424 }
425 }
426 mutex_unlock(&tty_mutex);
427
428 return res;
429}
430EXPORT_SYMBOL_GPL(tty_find_polling_driver);
431#endif
432
433static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to)
434{
435 return 0;
436}
437
438static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
439{
440 return -EIO;
441}
442
443/* No kernel lock held - none needed ;) */
444static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
445{
446 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
447}
448
449static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
450 unsigned long arg)
451{
452 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
453}
454
455static long hung_up_tty_compat_ioctl(struct file *file,
456 unsigned int cmd, unsigned long arg)
457{
458 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
459}
460
461static int hung_up_tty_fasync(int fd, struct file *file, int on)
462{
463 return -ENOTTY;
464}
465
466static void tty_show_fdinfo(struct seq_file *m, struct file *file)
467{
468 struct tty_struct *tty = file_tty(file);
469
470 if (tty && tty->ops && tty->ops->show_fdinfo)
471 tty->ops->show_fdinfo(tty, m);
472}
473
474static const struct file_operations tty_fops = {
475 .llseek = no_llseek,
476 .read_iter = tty_read,
477 .write_iter = tty_write,
478 .splice_read = generic_file_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 .show_fdinfo = tty_show_fdinfo,
487};
488
489static const struct file_operations console_fops = {
490 .llseek = no_llseek,
491 .read_iter = tty_read,
492 .write_iter = redirected_tty_write,
493 .splice_read = generic_file_splice_read,
494 .splice_write = iter_file_splice_write,
495 .poll = tty_poll,
496 .unlocked_ioctl = tty_ioctl,
497 .compat_ioctl = tty_compat_ioctl,
498 .open = tty_open,
499 .release = tty_release,
500 .fasync = tty_fasync,
501};
502
503static const struct file_operations hung_up_tty_fops = {
504 .llseek = no_llseek,
505 .read_iter = hung_up_tty_read,
506 .write_iter = hung_up_tty_write,
507 .poll = hung_up_tty_poll,
508 .unlocked_ioctl = hung_up_tty_ioctl,
509 .compat_ioctl = hung_up_tty_compat_ioctl,
510 .release = tty_release,
511 .fasync = hung_up_tty_fasync,
512};
513
514static DEFINE_SPINLOCK(redirect_lock);
515static struct file *redirect;
516
517/**
518 * tty_wakeup - request more data
519 * @tty: terminal
520 *
521 * Internal and external helper for wakeups of tty. This function
522 * informs the line discipline if present that the driver is ready
523 * to receive more output data.
524 */
525
526void tty_wakeup(struct tty_struct *tty)
527{
528 struct tty_ldisc *ld;
529
530 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
531 ld = tty_ldisc_ref(tty);
532 if (ld) {
533 if (ld->ops->write_wakeup)
534 ld->ops->write_wakeup(tty);
535 tty_ldisc_deref(ld);
536 }
537 }
538 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
539}
540EXPORT_SYMBOL_GPL(tty_wakeup);
541
542/**
543 * tty_release_redirect - Release a redirect on a pty if present
544 * @tty: tty device
545 *
546 * This is available to the pty code so if the master closes, if the
547 * slave is a redirect it can release the redirect.
548 */
549static struct file *tty_release_redirect(struct tty_struct *tty)
550{
551 struct file *f = NULL;
552
553 spin_lock(&redirect_lock);
554 if (redirect && file_tty(redirect) == tty) {
555 f = redirect;
556 redirect = NULL;
557 }
558 spin_unlock(&redirect_lock);
559
560 return f;
561}
562
563/**
564 * __tty_hangup - actual handler for hangup events
565 * @tty: tty device
566 * @exit_session: if non-zero, signal all foreground group processes
567 *
568 * This can be called by a "kworker" kernel thread. That is process
569 * synchronous but doesn't hold any locks, so we need to make sure we
570 * have the appropriate locks for what we're doing.
571 *
572 * The hangup event clears any pending redirections onto the hung up
573 * device. It ensures future writes will error and it does the needed
574 * line discipline hangup and signal delivery. The tty object itself
575 * remains intact.
576 *
577 * Locking:
578 * BTM
579 * redirect lock for undoing redirection
580 * file list lock for manipulating list of ttys
581 * tty_ldiscs_lock from called functions
582 * termios_rwsem resetting termios data
583 * tasklist_lock to walk task list for hangup event
584 * ->siglock to protect ->signal/->sighand
585 */
586static void __tty_hangup(struct tty_struct *tty, int exit_session)
587{
588 struct file *cons_filp = NULL;
589 struct file *filp, *f;
590 struct tty_file_private *priv;
591 int closecount = 0, n;
592 int refs;
593
594 if (!tty)
595 return;
596
597 f = tty_release_redirect(tty);
598
599 tty_lock(tty);
600
601 if (test_bit(TTY_HUPPED, &tty->flags)) {
602 tty_unlock(tty);
603 return;
604 }
605
606 /*
607 * Some console devices aren't actually hung up for technical and
608 * historical reasons, which can lead to indefinite interruptible
609 * sleep in n_tty_read(). The following explicitly tells
610 * n_tty_read() to abort readers.
611 */
612 set_bit(TTY_HUPPING, &tty->flags);
613
614 /* inuse_filps is protected by the single tty lock,
615 * this really needs to change if we want to flush the
616 * workqueue with the lock held.
617 */
618 check_tty_count(tty, "tty_hangup");
619
620 spin_lock(&tty->files_lock);
621 /* This breaks for file handles being sent over AF_UNIX sockets ? */
622 list_for_each_entry(priv, &tty->tty_files, list) {
623 filp = priv->file;
624 if (filp->f_op->write_iter == redirected_tty_write)
625 cons_filp = filp;
626 if (filp->f_op->write_iter != tty_write)
627 continue;
628 closecount++;
629 __tty_fasync(-1, filp, 0); /* can't block */
630 filp->f_op = &hung_up_tty_fops;
631 }
632 spin_unlock(&tty->files_lock);
633
634 refs = tty_signal_session_leader(tty, exit_session);
635 /* Account for the p->signal references we killed */
636 while (refs--)
637 tty_kref_put(tty);
638
639 tty_ldisc_hangup(tty, cons_filp != NULL);
640
641 spin_lock_irq(&tty->ctrl.lock);
642 clear_bit(TTY_THROTTLED, &tty->flags);
643 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
644 put_pid(tty->ctrl.session);
645 put_pid(tty->ctrl.pgrp);
646 tty->ctrl.session = NULL;
647 tty->ctrl.pgrp = NULL;
648 tty->ctrl.pktstatus = 0;
649 spin_unlock_irq(&tty->ctrl.lock);
650
651 /*
652 * If one of the devices matches a console pointer, we
653 * cannot just call hangup() because that will cause
654 * tty->count and state->count to go out of sync.
655 * So we just call close() the right number of times.
656 */
657 if (cons_filp) {
658 if (tty->ops->close)
659 for (n = 0; n < closecount; n++)
660 tty->ops->close(tty, cons_filp);
661 } else if (tty->ops->hangup)
662 tty->ops->hangup(tty);
663 /*
664 * We don't want to have driver/ldisc interactions beyond the ones
665 * we did here. The driver layer expects no calls after ->hangup()
666 * from the ldisc side, which is now guaranteed.
667 */
668 set_bit(TTY_HUPPED, &tty->flags);
669 clear_bit(TTY_HUPPING, &tty->flags);
670 tty_unlock(tty);
671
672 if (f)
673 fput(f);
674}
675
676static void do_tty_hangup(struct work_struct *work)
677{
678 struct tty_struct *tty =
679 container_of(work, struct tty_struct, hangup_work);
680
681 __tty_hangup(tty, 0);
682}
683
684/**
685 * tty_hangup - trigger a hangup event
686 * @tty: tty to hangup
687 *
688 * A carrier loss (virtual or otherwise) has occurred on this like
689 * schedule a hangup sequence to run after this event.
690 */
691
692void tty_hangup(struct tty_struct *tty)
693{
694 tty_debug_hangup(tty, "hangup\n");
695 schedule_work(&tty->hangup_work);
696}
697EXPORT_SYMBOL(tty_hangup);
698
699/**
700 * tty_vhangup - process vhangup
701 * @tty: tty to hangup
702 *
703 * The user has asked via system call for the terminal to be hung up.
704 * We do this synchronously so that when the syscall returns the process
705 * is complete. That guarantee is necessary for security reasons.
706 */
707
708void tty_vhangup(struct tty_struct *tty)
709{
710 tty_debug_hangup(tty, "vhangup\n");
711 __tty_hangup(tty, 0);
712}
713EXPORT_SYMBOL(tty_vhangup);
714
715
716/**
717 * tty_vhangup_self - process vhangup for own ctty
718 *
719 * Perform a vhangup on the current controlling tty
720 */
721
722void tty_vhangup_self(void)
723{
724 struct tty_struct *tty;
725
726 tty = get_current_tty();
727 if (tty) {
728 tty_vhangup(tty);
729 tty_kref_put(tty);
730 }
731}
732
733/**
734 * tty_vhangup_session - hangup session leader exit
735 * @tty: tty to hangup
736 *
737 * The session leader is exiting and hanging up its controlling terminal.
738 * Every process in the foreground process group is signalled SIGHUP.
739 *
740 * We do this synchronously so that when the syscall returns the process
741 * is complete. That guarantee is necessary for security reasons.
742 */
743
744void tty_vhangup_session(struct tty_struct *tty)
745{
746 tty_debug_hangup(tty, "session hangup\n");
747 __tty_hangup(tty, 1);
748}
749
750/**
751 * tty_hung_up_p - was tty hung up
752 * @filp: file pointer of tty
753 *
754 * Return true if the tty has been subject to a vhangup or a carrier
755 * loss
756 */
757
758int tty_hung_up_p(struct file *filp)
759{
760 return (filp && filp->f_op == &hung_up_tty_fops);
761}
762EXPORT_SYMBOL(tty_hung_up_p);
763
764void __stop_tty(struct tty_struct *tty)
765{
766 if (tty->flow.stopped)
767 return;
768 tty->flow.stopped = true;
769 if (tty->ops->stop)
770 tty->ops->stop(tty);
771}
772
773/**
774 * stop_tty - propagate flow control
775 * @tty: tty to stop
776 *
777 * Perform flow control to the driver. May be called
778 * on an already stopped device and will not re-call the driver
779 * method.
780 *
781 * This functionality is used by both the line disciplines for
782 * halting incoming flow and by the driver. It may therefore be
783 * called from any context, may be under the tty atomic_write_lock
784 * but not always.
785 *
786 * Locking:
787 * flow.lock
788 */
789void stop_tty(struct tty_struct *tty)
790{
791 unsigned long flags;
792
793 spin_lock_irqsave(&tty->flow.lock, flags);
794 __stop_tty(tty);
795 spin_unlock_irqrestore(&tty->flow.lock, flags);
796}
797EXPORT_SYMBOL(stop_tty);
798
799void __start_tty(struct tty_struct *tty)
800{
801 if (!tty->flow.stopped || tty->flow.tco_stopped)
802 return;
803 tty->flow.stopped = false;
804 if (tty->ops->start)
805 tty->ops->start(tty);
806 tty_wakeup(tty);
807}
808
809/**
810 * start_tty - propagate flow control
811 * @tty: tty to start
812 *
813 * Start a tty that has been stopped if at all possible. If this
814 * tty was previous stopped and is now being started, the driver
815 * start method is invoked and the line discipline woken.
816 *
817 * Locking:
818 * flow.lock
819 */
820void start_tty(struct tty_struct *tty)
821{
822 unsigned long flags;
823
824 spin_lock_irqsave(&tty->flow.lock, flags);
825 __start_tty(tty);
826 spin_unlock_irqrestore(&tty->flow.lock, flags);
827}
828EXPORT_SYMBOL(start_tty);
829
830static void tty_update_time(struct timespec64 *time)
831{
832 time64_t sec = ktime_get_real_seconds();
833
834 /*
835 * We only care if the two values differ in anything other than the
836 * lower three bits (i.e every 8 seconds). If so, then we can update
837 * the time of the tty device, otherwise it could be construded as a
838 * security leak to let userspace know the exact timing of the tty.
839 */
840 if ((sec ^ time->tv_sec) & ~7)
841 time->tv_sec = sec;
842}
843
844/*
845 * Iterate on the ldisc ->read() function until we've gotten all
846 * the data the ldisc has for us.
847 *
848 * The "cookie" is something that the ldisc read function can fill
849 * in to let us know that there is more data to be had.
850 *
851 * We promise to continue to call the ldisc until it stops returning
852 * data or clears the cookie. The cookie may be something that the
853 * ldisc maintains state for and needs to free.
854 */
855static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
856 struct file *file, struct iov_iter *to)
857{
858 int retval = 0;
859 void *cookie = NULL;
860 unsigned long offset = 0;
861 char kernel_buf[64];
862 size_t count = iov_iter_count(to);
863
864 do {
865 int size, copied;
866
867 size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count;
868 size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
869 if (!size)
870 break;
871
872 if (size < 0) {
873 /* Did we have an earlier error (ie -EFAULT)? */
874 if (retval)
875 break;
876 retval = size;
877
878 /*
879 * -EOVERFLOW means we didn't have enough space
880 * for a whole packet, and we shouldn't return
881 * a partial result.
882 */
883 if (retval == -EOVERFLOW)
884 offset = 0;
885 break;
886 }
887
888 copied = copy_to_iter(kernel_buf, size, to);
889 offset += copied;
890 count -= copied;
891
892 /*
893 * If the user copy failed, we still need to do another ->read()
894 * call if we had a cookie to let the ldisc clear up.
895 *
896 * But make sure size is zeroed.
897 */
898 if (unlikely(copied != size)) {
899 count = 0;
900 retval = -EFAULT;
901 }
902 } while (cookie);
903
904 /* We always clear tty buffer in case they contained passwords */
905 memzero_explicit(kernel_buf, sizeof(kernel_buf));
906 return offset ? offset : retval;
907}
908
909
910/**
911 * tty_read - read method for tty device files
912 * @iocb: kernel I/O control block
913 * @to: destination for the data read
914 *
915 * Perform the read system call function on this terminal device. Checks
916 * for hung up devices before calling the line discipline method.
917 *
918 * Locking:
919 * Locks the line discipline internally while needed. Multiple
920 * read calls may be outstanding in parallel.
921 */
922
923static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
924{
925 int i;
926 struct file *file = iocb->ki_filp;
927 struct inode *inode = file_inode(file);
928 struct tty_struct *tty = file_tty(file);
929 struct tty_ldisc *ld;
930
931 if (tty_paranoia_check(tty, inode, "tty_read"))
932 return -EIO;
933 if (!tty || tty_io_error(tty))
934 return -EIO;
935
936 /* We want to wait for the line discipline to sort out in this
937 * situation.
938 */
939 ld = tty_ldisc_ref_wait(tty);
940 if (!ld)
941 return hung_up_tty_read(iocb, to);
942 i = -EIO;
943 if (ld->ops->read)
944 i = iterate_tty_read(ld, tty, file, to);
945 tty_ldisc_deref(ld);
946
947 if (i > 0)
948 tty_update_time(&inode->i_atime);
949
950 return i;
951}
952
953static void tty_write_unlock(struct tty_struct *tty)
954{
955 mutex_unlock(&tty->atomic_write_lock);
956 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
957}
958
959static int tty_write_lock(struct tty_struct *tty, int ndelay)
960{
961 if (!mutex_trylock(&tty->atomic_write_lock)) {
962 if (ndelay)
963 return -EAGAIN;
964 if (mutex_lock_interruptible(&tty->atomic_write_lock))
965 return -ERESTARTSYS;
966 }
967 return 0;
968}
969
970/*
971 * Split writes up in sane blocksizes to avoid
972 * denial-of-service type attacks
973 */
974static inline ssize_t do_tty_write(
975 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
976 struct tty_struct *tty,
977 struct file *file,
978 struct iov_iter *from)
979{
980 size_t count = iov_iter_count(from);
981 ssize_t ret, written = 0;
982 unsigned int chunk;
983
984 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
985 if (ret < 0)
986 return ret;
987
988 /*
989 * We chunk up writes into a temporary buffer. This
990 * simplifies low-level drivers immensely, since they
991 * don't have locking issues and user mode accesses.
992 *
993 * But if TTY_NO_WRITE_SPLIT is set, we should use a
994 * big chunk-size..
995 *
996 * The default chunk-size is 2kB, because the NTTY
997 * layer has problems with bigger chunks. It will
998 * claim to be able to handle more characters than
999 * it actually does.
1000 *
1001 * FIXME: This can probably go away now except that 64K chunks
1002 * are too likely to fail unless switched to vmalloc...
1003 */
1004 chunk = 2048;
1005 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1006 chunk = 65536;
1007 if (count < chunk)
1008 chunk = count;
1009
1010 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1011 if (tty->write_cnt < chunk) {
1012 unsigned char *buf_chunk;
1013
1014 if (chunk < 1024)
1015 chunk = 1024;
1016
1017 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1018 if (!buf_chunk) {
1019 ret = -ENOMEM;
1020 goto out;
1021 }
1022 kfree(tty->write_buf);
1023 tty->write_cnt = chunk;
1024 tty->write_buf = buf_chunk;
1025 }
1026
1027 /* Do the write .. */
1028 for (;;) {
1029 size_t size = count;
1030
1031 if (size > chunk)
1032 size = chunk;
1033
1034 ret = -EFAULT;
1035 if (copy_from_iter(tty->write_buf, size, from) != size)
1036 break;
1037
1038 ret = write(tty, file, tty->write_buf, size);
1039 if (ret <= 0)
1040 break;
1041
1042 written += ret;
1043 if (ret > size)
1044 break;
1045
1046 /* FIXME! Have Al check this! */
1047 if (ret != size)
1048 iov_iter_revert(from, size-ret);
1049
1050 count -= ret;
1051 if (!count)
1052 break;
1053 ret = -ERESTARTSYS;
1054 if (signal_pending(current))
1055 break;
1056 cond_resched();
1057 }
1058 if (written) {
1059 tty_update_time(&file_inode(file)->i_mtime);
1060 ret = written;
1061 }
1062out:
1063 tty_write_unlock(tty);
1064 return ret;
1065}
1066
1067/**
1068 * tty_write_message - write a message to a certain tty, not just the console.
1069 * @tty: the destination tty_struct
1070 * @msg: the message to write
1071 *
1072 * This is used for messages that need to be redirected to a specific tty.
1073 * We don't put it into the syslog queue right now maybe in the future if
1074 * really needed.
1075 *
1076 * We must still hold the BTM and test the CLOSING flag for the moment.
1077 */
1078
1079void tty_write_message(struct tty_struct *tty, char *msg)
1080{
1081 if (tty) {
1082 mutex_lock(&tty->atomic_write_lock);
1083 tty_lock(tty);
1084 if (tty->ops->write && tty->count > 0)
1085 tty->ops->write(tty, msg, strlen(msg));
1086 tty_unlock(tty);
1087 tty_write_unlock(tty);
1088 }
1089}
1090
1091static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_iter *from)
1092{
1093 struct tty_struct *tty = file_tty(file);
1094 struct tty_ldisc *ld;
1095 ssize_t ret;
1096
1097 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1098 return -EIO;
1099 if (!tty || !tty->ops->write || tty_io_error(tty))
1100 return -EIO;
1101 /* Short term debug to catch buggy drivers */
1102 if (tty->ops->write_room == NULL)
1103 tty_err(tty, "missing write_room method\n");
1104 ld = tty_ldisc_ref_wait(tty);
1105 if (!ld)
1106 return hung_up_tty_write(iocb, from);
1107 if (!ld->ops->write)
1108 ret = -EIO;
1109 else
1110 ret = do_tty_write(ld->ops->write, tty, file, from);
1111 tty_ldisc_deref(ld);
1112 return ret;
1113}
1114
1115/**
1116 * tty_write - write method for tty device file
1117 * @iocb: kernel I/O control block
1118 * @from: iov_iter with data to write
1119 *
1120 * Write data to a tty device via the line discipline.
1121 *
1122 * Locking:
1123 * Locks the line discipline as required
1124 * Writes to the tty driver are serialized by the atomic_write_lock
1125 * and are then processed in chunks to the device. The line
1126 * discipline write method will not be invoked in parallel for
1127 * each device.
1128 */
1129static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from)
1130{
1131 return file_tty_write(iocb->ki_filp, iocb, from);
1132}
1133
1134ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter)
1135{
1136 struct file *p = NULL;
1137
1138 spin_lock(&redirect_lock);
1139 if (redirect)
1140 p = get_file(redirect);
1141 spin_unlock(&redirect_lock);
1142
1143 /*
1144 * We know the redirected tty is just another tty, we can
1145 * call file_tty_write() directly with that file pointer.
1146 */
1147 if (p) {
1148 ssize_t res;
1149
1150 res = file_tty_write(p, iocb, iter);
1151 fput(p);
1152 return res;
1153 }
1154 return tty_write(iocb, iter);
1155}
1156
1157/*
1158 * tty_send_xchar - send priority character
1159 *
1160 * Send a high priority character to the tty even if stopped
1161 *
1162 * Locking: none for xchar method, write ordering for write method.
1163 */
1164
1165int tty_send_xchar(struct tty_struct *tty, char ch)
1166{
1167 bool was_stopped = tty->flow.stopped;
1168
1169 if (tty->ops->send_xchar) {
1170 down_read(&tty->termios_rwsem);
1171 tty->ops->send_xchar(tty, ch);
1172 up_read(&tty->termios_rwsem);
1173 return 0;
1174 }
1175
1176 if (tty_write_lock(tty, 0) < 0)
1177 return -ERESTARTSYS;
1178
1179 down_read(&tty->termios_rwsem);
1180 if (was_stopped)
1181 start_tty(tty);
1182 tty->ops->write(tty, &ch, 1);
1183 if (was_stopped)
1184 stop_tty(tty);
1185 up_read(&tty->termios_rwsem);
1186 tty_write_unlock(tty);
1187 return 0;
1188}
1189
1190/**
1191 * pty_line_name - generate name for a pty
1192 * @driver: the tty driver in use
1193 * @index: the minor number
1194 * @p: output buffer of at least 6 bytes
1195 *
1196 * Generate a name from a driver reference and write it to the output
1197 * buffer.
1198 *
1199 * Locking: None
1200 */
1201static void pty_line_name(struct tty_driver *driver, int index, char *p)
1202{
1203 static const char ptychar[] = "pqrstuvwxyzabcde";
1204 int i = index + driver->name_base;
1205 /* ->name is initialized to "ttyp", but "tty" is expected */
1206 sprintf(p, "%s%c%x",
1207 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1208 ptychar[i >> 4 & 0xf], i & 0xf);
1209}
1210
1211/**
1212 * tty_line_name - generate name for a tty
1213 * @driver: the tty driver in use
1214 * @index: the minor number
1215 * @p: output buffer of at least 7 bytes
1216 *
1217 * Generate a name from a driver reference and write it to the output
1218 * buffer.
1219 *
1220 * Locking: None
1221 */
1222static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1223{
1224 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1225 return sprintf(p, "%s", driver->name);
1226 else
1227 return sprintf(p, "%s%d", driver->name,
1228 index + driver->name_base);
1229}
1230
1231/**
1232 * tty_driver_lookup_tty() - find an existing tty, if any
1233 * @driver: the driver for the tty
1234 * @file: file object
1235 * @idx: the minor number
1236 *
1237 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1238 * driver lookup() method returns an error.
1239 *
1240 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1241 */
1242static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1243 struct file *file, int idx)
1244{
1245 struct tty_struct *tty;
1246
1247 if (driver->ops->lookup)
1248 if (!file)
1249 tty = ERR_PTR(-EIO);
1250 else
1251 tty = driver->ops->lookup(driver, file, idx);
1252 else
1253 tty = driver->ttys[idx];
1254
1255 if (!IS_ERR(tty))
1256 tty_kref_get(tty);
1257 return tty;
1258}
1259
1260/**
1261 * tty_init_termios - helper for termios setup
1262 * @tty: the tty to set up
1263 *
1264 * Initialise the termios structure for this tty. This runs under
1265 * the tty_mutex currently so we can be relaxed about ordering.
1266 */
1267
1268void tty_init_termios(struct tty_struct *tty)
1269{
1270 struct ktermios *tp;
1271 int idx = tty->index;
1272
1273 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1274 tty->termios = tty->driver->init_termios;
1275 else {
1276 /* Check for lazy saved data */
1277 tp = tty->driver->termios[idx];
1278 if (tp != NULL) {
1279 tty->termios = *tp;
1280 tty->termios.c_line = tty->driver->init_termios.c_line;
1281 } else
1282 tty->termios = tty->driver->init_termios;
1283 }
1284 /* Compatibility until drivers always set this */
1285 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1286 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1287}
1288EXPORT_SYMBOL_GPL(tty_init_termios);
1289
1290int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1291{
1292 tty_init_termios(tty);
1293 tty_driver_kref_get(driver);
1294 tty->count++;
1295 driver->ttys[tty->index] = tty;
1296 return 0;
1297}
1298EXPORT_SYMBOL_GPL(tty_standard_install);
1299
1300/**
1301 * tty_driver_install_tty() - install a tty entry in the driver
1302 * @driver: the driver for the tty
1303 * @tty: the tty
1304 *
1305 * Install a tty object into the driver tables. The tty->index field
1306 * will be set by the time this is called. This method is responsible
1307 * for ensuring any need additional structures are allocated and
1308 * configured.
1309 *
1310 * Locking: tty_mutex for now
1311 */
1312static int tty_driver_install_tty(struct tty_driver *driver,
1313 struct tty_struct *tty)
1314{
1315 return driver->ops->install ? driver->ops->install(driver, tty) :
1316 tty_standard_install(driver, tty);
1317}
1318
1319/**
1320 * tty_driver_remove_tty() - remove a tty from the driver tables
1321 * @driver: the driver for the tty
1322 * @tty: tty to remove
1323 *
1324 * Remvoe a tty object from the driver tables. The tty->index field
1325 * will be set by the time this is called.
1326 *
1327 * Locking: tty_mutex for now
1328 */
1329static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1330{
1331 if (driver->ops->remove)
1332 driver->ops->remove(driver, tty);
1333 else
1334 driver->ttys[tty->index] = NULL;
1335}
1336
1337/**
1338 * tty_reopen() - fast re-open of an open tty
1339 * @tty: the tty to open
1340 *
1341 * Return 0 on success, -errno on error.
1342 * Re-opens on master ptys are not allowed and return -EIO.
1343 *
1344 * Locking: Caller must hold tty_lock
1345 */
1346static int tty_reopen(struct tty_struct *tty)
1347{
1348 struct tty_driver *driver = tty->driver;
1349 struct tty_ldisc *ld;
1350 int retval = 0;
1351
1352 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1353 driver->subtype == PTY_TYPE_MASTER)
1354 return -EIO;
1355
1356 if (!tty->count)
1357 return -EAGAIN;
1358
1359 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1360 return -EBUSY;
1361
1362 ld = tty_ldisc_ref_wait(tty);
1363 if (ld) {
1364 tty_ldisc_deref(ld);
1365 } else {
1366 retval = tty_ldisc_lock(tty, 5 * HZ);
1367 if (retval)
1368 return retval;
1369
1370 if (!tty->ldisc)
1371 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1372 tty_ldisc_unlock(tty);
1373 }
1374
1375 if (retval == 0)
1376 tty->count++;
1377
1378 return retval;
1379}
1380
1381/**
1382 * tty_init_dev - initialise a tty device
1383 * @driver: tty driver we are opening a device on
1384 * @idx: device index
1385 *
1386 * Prepare a tty device. This may not be a "new" clean device but
1387 * could also be an active device. The pty drivers require special
1388 * handling because of this.
1389 *
1390 * Locking:
1391 * The function is called under the tty_mutex, which
1392 * protects us from the tty struct or driver itself going away.
1393 *
1394 * On exit the tty device has the line discipline attached and
1395 * a reference count of 1. If a pair was created for pty/tty use
1396 * and the other was a pty master then it too has a reference count of 1.
1397 *
1398 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1399 * failed open. The new code protects the open with a mutex, so it's
1400 * really quite straightforward. The mutex locking can probably be
1401 * relaxed for the (most common) case of reopening a tty.
1402 *
1403 * Return: returned tty structure
1404 */
1405
1406struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1407{
1408 struct tty_struct *tty;
1409 int retval;
1410
1411 /*
1412 * First time open is complex, especially for PTY devices.
1413 * This code guarantees that either everything succeeds and the
1414 * TTY is ready for operation, or else the table slots are vacated
1415 * and the allocated memory released. (Except that the termios
1416 * may be retained.)
1417 */
1418
1419 if (!try_module_get(driver->owner))
1420 return ERR_PTR(-ENODEV);
1421
1422 tty = alloc_tty_struct(driver, idx);
1423 if (!tty) {
1424 retval = -ENOMEM;
1425 goto err_module_put;
1426 }
1427
1428 tty_lock(tty);
1429 retval = tty_driver_install_tty(driver, tty);
1430 if (retval < 0)
1431 goto err_free_tty;
1432
1433 if (!tty->port)
1434 tty->port = driver->ports[idx];
1435
1436 if (WARN_RATELIMIT(!tty->port,
1437 "%s: %s driver does not set tty->port. This would crash the kernel. Fix the driver!\n",
1438 __func__, tty->driver->name)) {
1439 retval = -EINVAL;
1440 goto err_release_lock;
1441 }
1442
1443 retval = tty_ldisc_lock(tty, 5 * HZ);
1444 if (retval)
1445 goto err_release_lock;
1446 tty->port->itty = tty;
1447
1448 /*
1449 * Structures all installed ... call the ldisc open routines.
1450 * If we fail here just call release_tty to clean up. No need
1451 * to decrement the use counts, as release_tty doesn't care.
1452 */
1453 retval = tty_ldisc_setup(tty, tty->link);
1454 if (retval)
1455 goto err_release_tty;
1456 tty_ldisc_unlock(tty);
1457 /* Return the tty locked so that it cannot vanish under the caller */
1458 return tty;
1459
1460err_free_tty:
1461 tty_unlock(tty);
1462 free_tty_struct(tty);
1463err_module_put:
1464 module_put(driver->owner);
1465 return ERR_PTR(retval);
1466
1467 /* call the tty release_tty routine to clean out this slot */
1468err_release_tty:
1469 tty_ldisc_unlock(tty);
1470 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1471 retval, idx);
1472err_release_lock:
1473 tty_unlock(tty);
1474 release_tty(tty, idx);
1475 return ERR_PTR(retval);
1476}
1477
1478/**
1479 * tty_save_termios() - save tty termios data in driver table
1480 * @tty: tty whose termios data to save
1481 *
1482 * Locking: Caller guarantees serialisation with tty_init_termios().
1483 */
1484void tty_save_termios(struct tty_struct *tty)
1485{
1486 struct ktermios *tp;
1487 int idx = tty->index;
1488
1489 /* If the port is going to reset then it has no termios to save */
1490 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1491 return;
1492
1493 /* Stash the termios data */
1494 tp = tty->driver->termios[idx];
1495 if (tp == NULL) {
1496 tp = kmalloc(sizeof(*tp), GFP_KERNEL);
1497 if (tp == NULL)
1498 return;
1499 tty->driver->termios[idx] = tp;
1500 }
1501 *tp = tty->termios;
1502}
1503EXPORT_SYMBOL_GPL(tty_save_termios);
1504
1505/**
1506 * tty_flush_works - flush all works of a tty/pty pair
1507 * @tty: tty device to flush works for (or either end of a pty pair)
1508 *
1509 * Sync flush all works belonging to @tty (and the 'other' tty).
1510 */
1511static void tty_flush_works(struct tty_struct *tty)
1512{
1513 flush_work(&tty->SAK_work);
1514 flush_work(&tty->hangup_work);
1515 if (tty->link) {
1516 flush_work(&tty->link->SAK_work);
1517 flush_work(&tty->link->hangup_work);
1518 }
1519}
1520
1521/**
1522 * release_one_tty - release tty structure memory
1523 * @work: work of tty we are obliterating
1524 *
1525 * Releases memory associated with a tty structure, and clears out the
1526 * driver table slots. This function is called when a device is no longer
1527 * in use. It also gets called when setup of a device fails.
1528 *
1529 * Locking:
1530 * takes the file list lock internally when working on the list
1531 * of ttys that the driver keeps.
1532 *
1533 * This method gets called from a work queue so that the driver private
1534 * cleanup ops can sleep (needed for USB at least)
1535 */
1536static void release_one_tty(struct work_struct *work)
1537{
1538 struct tty_struct *tty =
1539 container_of(work, struct tty_struct, hangup_work);
1540 struct tty_driver *driver = tty->driver;
1541 struct module *owner = driver->owner;
1542
1543 if (tty->ops->cleanup)
1544 tty->ops->cleanup(tty);
1545
1546 tty->magic = 0;
1547 tty_driver_kref_put(driver);
1548 module_put(owner);
1549
1550 spin_lock(&tty->files_lock);
1551 list_del_init(&tty->tty_files);
1552 spin_unlock(&tty->files_lock);
1553
1554 put_pid(tty->ctrl.pgrp);
1555 put_pid(tty->ctrl.session);
1556 free_tty_struct(tty);
1557}
1558
1559static void queue_release_one_tty(struct kref *kref)
1560{
1561 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1562
1563 /* The hangup queue is now free so we can reuse it rather than
1564 * waste a chunk of memory for each port.
1565 */
1566 INIT_WORK(&tty->hangup_work, release_one_tty);
1567 schedule_work(&tty->hangup_work);
1568}
1569
1570/**
1571 * tty_kref_put - release a tty kref
1572 * @tty: tty device
1573 *
1574 * Release a reference to a tty device and if need be let the kref
1575 * layer destruct the object for us
1576 */
1577
1578void tty_kref_put(struct tty_struct *tty)
1579{
1580 if (tty)
1581 kref_put(&tty->kref, queue_release_one_tty);
1582}
1583EXPORT_SYMBOL(tty_kref_put);
1584
1585/**
1586 * release_tty - release tty structure memory
1587 * @tty: tty device release
1588 * @idx: index of the tty device release
1589 *
1590 * Release both @tty and a possible linked partner (think pty pair),
1591 * and decrement the refcount of the backing module.
1592 *
1593 * Locking:
1594 * tty_mutex
1595 * takes the file list lock internally when working on the list
1596 * of ttys that the driver keeps.
1597 *
1598 */
1599static void release_tty(struct tty_struct *tty, int idx)
1600{
1601 /* This should always be true but check for the moment */
1602 WARN_ON(tty->index != idx);
1603 WARN_ON(!mutex_is_locked(&tty_mutex));
1604 if (tty->ops->shutdown)
1605 tty->ops->shutdown(tty);
1606 tty_save_termios(tty);
1607 tty_driver_remove_tty(tty->driver, tty);
1608 if (tty->port)
1609 tty->port->itty = NULL;
1610 if (tty->link)
1611 tty->link->port->itty = NULL;
1612 if (tty->port)
1613 tty_buffer_cancel_work(tty->port);
1614 if (tty->link)
1615 tty_buffer_cancel_work(tty->link->port);
1616
1617 tty_kref_put(tty->link);
1618 tty_kref_put(tty);
1619}
1620
1621/**
1622 * tty_release_checks - check a tty before real release
1623 * @tty: tty to check
1624 * @idx: index of the tty
1625 *
1626 * Performs some paranoid checking before true release of the @tty.
1627 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1628 */
1629static int tty_release_checks(struct tty_struct *tty, int idx)
1630{
1631#ifdef TTY_PARANOIA_CHECK
1632 if (idx < 0 || idx >= tty->driver->num) {
1633 tty_debug(tty, "bad idx %d\n", idx);
1634 return -1;
1635 }
1636
1637 /* not much to check for devpts */
1638 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1639 return 0;
1640
1641 if (tty != tty->driver->ttys[idx]) {
1642 tty_debug(tty, "bad driver table[%d] = %p\n",
1643 idx, tty->driver->ttys[idx]);
1644 return -1;
1645 }
1646 if (tty->driver->other) {
1647 struct tty_struct *o_tty = tty->link;
1648
1649 if (o_tty != tty->driver->other->ttys[idx]) {
1650 tty_debug(tty, "bad other table[%d] = %p\n",
1651 idx, tty->driver->other->ttys[idx]);
1652 return -1;
1653 }
1654 if (o_tty->link != tty) {
1655 tty_debug(tty, "bad link = %p\n", o_tty->link);
1656 return -1;
1657 }
1658 }
1659#endif
1660 return 0;
1661}
1662
1663/**
1664 * tty_kclose - closes tty opened by tty_kopen
1665 * @tty: tty device
1666 *
1667 * Performs the final steps to release and free a tty device. It is the
1668 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1669 * flag on tty->port.
1670 */
1671void tty_kclose(struct tty_struct *tty)
1672{
1673 /*
1674 * Ask the line discipline code to release its structures
1675 */
1676 tty_ldisc_release(tty);
1677
1678 /* Wait for pending work before tty destruction commmences */
1679 tty_flush_works(tty);
1680
1681 tty_debug_hangup(tty, "freeing structure\n");
1682 /*
1683 * The release_tty function takes care of the details of clearing
1684 * the slots and preserving the termios structure.
1685 */
1686 mutex_lock(&tty_mutex);
1687 tty_port_set_kopened(tty->port, 0);
1688 release_tty(tty, tty->index);
1689 mutex_unlock(&tty_mutex);
1690}
1691EXPORT_SYMBOL_GPL(tty_kclose);
1692
1693/**
1694 * tty_release_struct - release a tty struct
1695 * @tty: tty device
1696 * @idx: index of the tty
1697 *
1698 * Performs the final steps to release and free a tty device. It is
1699 * roughly the reverse of tty_init_dev.
1700 */
1701void tty_release_struct(struct tty_struct *tty, int idx)
1702{
1703 /*
1704 * Ask the line discipline code to release its structures
1705 */
1706 tty_ldisc_release(tty);
1707
1708 /* Wait for pending work before tty destruction commmences */
1709 tty_flush_works(tty);
1710
1711 tty_debug_hangup(tty, "freeing structure\n");
1712 /*
1713 * The release_tty function takes care of the details of clearing
1714 * the slots and preserving the termios structure.
1715 */
1716 mutex_lock(&tty_mutex);
1717 release_tty(tty, idx);
1718 mutex_unlock(&tty_mutex);
1719}
1720EXPORT_SYMBOL_GPL(tty_release_struct);
1721
1722/**
1723 * tty_release - vfs callback for close
1724 * @inode: inode of tty
1725 * @filp: file pointer for handle to tty
1726 *
1727 * Called the last time each file handle is closed that references
1728 * this tty. There may however be several such references.
1729 *
1730 * Locking:
1731 * Takes bkl. See tty_release_dev
1732 *
1733 * Even releasing the tty structures is a tricky business.. We have
1734 * to be very careful that the structures are all released at the
1735 * same time, as interrupts might otherwise get the wrong pointers.
1736 *
1737 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1738 * lead to double frees or releasing memory still in use.
1739 */
1740
1741int tty_release(struct inode *inode, struct file *filp)
1742{
1743 struct tty_struct *tty = file_tty(filp);
1744 struct tty_struct *o_tty = NULL;
1745 int do_sleep, final;
1746 int idx;
1747 long timeout = 0;
1748 int once = 1;
1749
1750 if (tty_paranoia_check(tty, inode, __func__))
1751 return 0;
1752
1753 tty_lock(tty);
1754 check_tty_count(tty, __func__);
1755
1756 __tty_fasync(-1, filp, 0);
1757
1758 idx = tty->index;
1759 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1760 tty->driver->subtype == PTY_TYPE_MASTER)
1761 o_tty = tty->link;
1762
1763 if (tty_release_checks(tty, idx)) {
1764 tty_unlock(tty);
1765 return 0;
1766 }
1767
1768 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1769
1770 if (tty->ops->close)
1771 tty->ops->close(tty, filp);
1772
1773 /* If tty is pty master, lock the slave pty (stable lock order) */
1774 tty_lock_slave(o_tty);
1775
1776 /*
1777 * Sanity check: if tty->count is going to zero, there shouldn't be
1778 * any waiters on tty->read_wait or tty->write_wait. We test the
1779 * wait queues and kick everyone out _before_ actually starting to
1780 * close. This ensures that we won't block while releasing the tty
1781 * structure.
1782 *
1783 * The test for the o_tty closing is necessary, since the master and
1784 * slave sides may close in any order. If the slave side closes out
1785 * first, its count will be one, since the master side holds an open.
1786 * Thus this test wouldn't be triggered at the time the slave closed,
1787 * so we do it now.
1788 */
1789 while (1) {
1790 do_sleep = 0;
1791
1792 if (tty->count <= 1) {
1793 if (waitqueue_active(&tty->read_wait)) {
1794 wake_up_poll(&tty->read_wait, EPOLLIN);
1795 do_sleep++;
1796 }
1797 if (waitqueue_active(&tty->write_wait)) {
1798 wake_up_poll(&tty->write_wait, EPOLLOUT);
1799 do_sleep++;
1800 }
1801 }
1802 if (o_tty && o_tty->count <= 1) {
1803 if (waitqueue_active(&o_tty->read_wait)) {
1804 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1805 do_sleep++;
1806 }
1807 if (waitqueue_active(&o_tty->write_wait)) {
1808 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1809 do_sleep++;
1810 }
1811 }
1812 if (!do_sleep)
1813 break;
1814
1815 if (once) {
1816 once = 0;
1817 tty_warn(tty, "read/write wait queue active!\n");
1818 }
1819 schedule_timeout_killable(timeout);
1820 if (timeout < 120 * HZ)
1821 timeout = 2 * timeout + 1;
1822 else
1823 timeout = MAX_SCHEDULE_TIMEOUT;
1824 }
1825
1826 if (o_tty) {
1827 if (--o_tty->count < 0) {
1828 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1829 o_tty->count = 0;
1830 }
1831 }
1832 if (--tty->count < 0) {
1833 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1834 tty->count = 0;
1835 }
1836
1837 /*
1838 * We've decremented tty->count, so we need to remove this file
1839 * descriptor off the tty->tty_files list; this serves two
1840 * purposes:
1841 * - check_tty_count sees the correct number of file descriptors
1842 * associated with this tty.
1843 * - do_tty_hangup no longer sees this file descriptor as
1844 * something that needs to be handled for hangups.
1845 */
1846 tty_del_file(filp);
1847
1848 /*
1849 * Perform some housekeeping before deciding whether to return.
1850 *
1851 * If _either_ side is closing, make sure there aren't any
1852 * processes that still think tty or o_tty is their controlling
1853 * tty.
1854 */
1855 if (!tty->count) {
1856 read_lock(&tasklist_lock);
1857 session_clear_tty(tty->ctrl.session);
1858 if (o_tty)
1859 session_clear_tty(o_tty->ctrl.session);
1860 read_unlock(&tasklist_lock);
1861 }
1862
1863 /* check whether both sides are closing ... */
1864 final = !tty->count && !(o_tty && o_tty->count);
1865
1866 tty_unlock_slave(o_tty);
1867 tty_unlock(tty);
1868
1869 /* At this point, the tty->count == 0 should ensure a dead tty
1870 * cannot be re-opened by a racing opener.
1871 */
1872
1873 if (!final)
1874 return 0;
1875
1876 tty_debug_hangup(tty, "final close\n");
1877
1878 tty_release_struct(tty, idx);
1879 return 0;
1880}
1881
1882/**
1883 * tty_open_current_tty - get locked tty of current task
1884 * @device: device number
1885 * @filp: file pointer to tty
1886 * @return: locked tty of the current task iff @device is /dev/tty
1887 *
1888 * Performs a re-open of the current task's controlling tty.
1889 *
1890 * We cannot return driver and index like for the other nodes because
1891 * devpts will not work then. It expects inodes to be from devpts FS.
1892 */
1893static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1894{
1895 struct tty_struct *tty;
1896 int retval;
1897
1898 if (device != MKDEV(TTYAUX_MAJOR, 0))
1899 return NULL;
1900
1901 tty = get_current_tty();
1902 if (!tty)
1903 return ERR_PTR(-ENXIO);
1904
1905 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1906 /* noctty = 1; */
1907 tty_lock(tty);
1908 tty_kref_put(tty); /* safe to drop the kref now */
1909
1910 retval = tty_reopen(tty);
1911 if (retval < 0) {
1912 tty_unlock(tty);
1913 tty = ERR_PTR(retval);
1914 }
1915 return tty;
1916}
1917
1918/**
1919 * tty_lookup_driver - lookup a tty driver for a given device file
1920 * @device: device number
1921 * @filp: file pointer to tty
1922 * @index: index for the device in the @return driver
1923 * @return: driver for this inode (with increased refcount)
1924 *
1925 * If @return is not erroneous, the caller is responsible to decrement the
1926 * refcount by tty_driver_kref_put.
1927 *
1928 * Locking: tty_mutex protects get_tty_driver
1929 */
1930static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1931 int *index)
1932{
1933 struct tty_driver *driver = NULL;
1934
1935 switch (device) {
1936#ifdef CONFIG_VT
1937 case MKDEV(TTY_MAJOR, 0): {
1938 extern struct tty_driver *console_driver;
1939
1940 driver = tty_driver_kref_get(console_driver);
1941 *index = fg_console;
1942 break;
1943 }
1944#endif
1945 case MKDEV(TTYAUX_MAJOR, 1): {
1946 struct tty_driver *console_driver = console_device(index);
1947
1948 if (console_driver) {
1949 driver = tty_driver_kref_get(console_driver);
1950 if (driver && filp) {
1951 /* Don't let /dev/console block */
1952 filp->f_flags |= O_NONBLOCK;
1953 break;
1954 }
1955 }
1956 if (driver)
1957 tty_driver_kref_put(driver);
1958 return ERR_PTR(-ENODEV);
1959 }
1960 default:
1961 driver = get_tty_driver(device, index);
1962 if (!driver)
1963 return ERR_PTR(-ENODEV);
1964 break;
1965 }
1966 return driver;
1967}
1968
1969static struct tty_struct *tty_kopen(dev_t device, int shared)
1970{
1971 struct tty_struct *tty;
1972 struct tty_driver *driver;
1973 int index = -1;
1974
1975 mutex_lock(&tty_mutex);
1976 driver = tty_lookup_driver(device, NULL, &index);
1977 if (IS_ERR(driver)) {
1978 mutex_unlock(&tty_mutex);
1979 return ERR_CAST(driver);
1980 }
1981
1982 /* check whether we're reopening an existing tty */
1983 tty = tty_driver_lookup_tty(driver, NULL, index);
1984 if (IS_ERR(tty) || shared)
1985 goto out;
1986
1987 if (tty) {
1988 /* drop kref from tty_driver_lookup_tty() */
1989 tty_kref_put(tty);
1990 tty = ERR_PTR(-EBUSY);
1991 } else { /* tty_init_dev returns tty with the tty_lock held */
1992 tty = tty_init_dev(driver, index);
1993 if (IS_ERR(tty))
1994 goto out;
1995 tty_port_set_kopened(tty->port, 1);
1996 }
1997out:
1998 mutex_unlock(&tty_mutex);
1999 tty_driver_kref_put(driver);
2000 return tty;
2001}
2002
2003/**
2004 * tty_kopen_exclusive - open a tty device for kernel
2005 * @device: dev_t of device to open
2006 *
2007 * Opens tty exclusively for kernel. Performs the driver lookup,
2008 * makes sure it's not already opened and performs the first-time
2009 * tty initialization.
2010 *
2011 * Returns the locked initialized &tty_struct
2012 *
2013 * Claims the global tty_mutex to serialize:
2014 * - concurrent first-time tty initialization
2015 * - concurrent tty driver removal w/ lookup
2016 * - concurrent tty removal from driver table
2017 */
2018struct tty_struct *tty_kopen_exclusive(dev_t device)
2019{
2020 return tty_kopen(device, 0);
2021}
2022EXPORT_SYMBOL_GPL(tty_kopen_exclusive);
2023
2024/**
2025 * tty_kopen_shared - open a tty device for shared in-kernel use
2026 * @device: dev_t of device to open
2027 *
2028 * Opens an already existing tty for in-kernel use. Compared to
2029 * tty_kopen_exclusive() above it doesn't ensure to be the only user.
2030 *
2031 * Locking is identical to tty_kopen() above.
2032 */
2033struct tty_struct *tty_kopen_shared(dev_t device)
2034{
2035 return tty_kopen(device, 1);
2036}
2037EXPORT_SYMBOL_GPL(tty_kopen_shared);
2038
2039/**
2040 * tty_open_by_driver - open a tty device
2041 * @device: dev_t of device to open
2042 * @filp: file pointer to tty
2043 *
2044 * Performs the driver lookup, checks for a reopen, or otherwise
2045 * performs the first-time tty initialization.
2046 *
2047 * Returns the locked initialized or re-opened &tty_struct
2048 *
2049 * Claims the global tty_mutex to serialize:
2050 * - concurrent first-time tty initialization
2051 * - concurrent tty driver removal w/ lookup
2052 * - concurrent tty removal from driver table
2053 */
2054static struct tty_struct *tty_open_by_driver(dev_t device,
2055 struct file *filp)
2056{
2057 struct tty_struct *tty;
2058 struct tty_driver *driver = NULL;
2059 int index = -1;
2060 int retval;
2061
2062 mutex_lock(&tty_mutex);
2063 driver = tty_lookup_driver(device, filp, &index);
2064 if (IS_ERR(driver)) {
2065 mutex_unlock(&tty_mutex);
2066 return ERR_CAST(driver);
2067 }
2068
2069 /* check whether we're reopening an existing tty */
2070 tty = tty_driver_lookup_tty(driver, filp, index);
2071 if (IS_ERR(tty)) {
2072 mutex_unlock(&tty_mutex);
2073 goto out;
2074 }
2075
2076 if (tty) {
2077 if (tty_port_kopened(tty->port)) {
2078 tty_kref_put(tty);
2079 mutex_unlock(&tty_mutex);
2080 tty = ERR_PTR(-EBUSY);
2081 goto out;
2082 }
2083 mutex_unlock(&tty_mutex);
2084 retval = tty_lock_interruptible(tty);
2085 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2086 if (retval) {
2087 if (retval == -EINTR)
2088 retval = -ERESTARTSYS;
2089 tty = ERR_PTR(retval);
2090 goto out;
2091 }
2092 retval = tty_reopen(tty);
2093 if (retval < 0) {
2094 tty_unlock(tty);
2095 tty = ERR_PTR(retval);
2096 }
2097 } else { /* Returns with the tty_lock held for now */
2098 tty = tty_init_dev(driver, index);
2099 mutex_unlock(&tty_mutex);
2100 }
2101out:
2102 tty_driver_kref_put(driver);
2103 return tty;
2104}
2105
2106/**
2107 * tty_open - open a tty device
2108 * @inode: inode of device file
2109 * @filp: file pointer to tty
2110 *
2111 * tty_open and tty_release keep up the tty count that contains the
2112 * number of opens done on a tty. We cannot use the inode-count, as
2113 * different inodes might point to the same tty.
2114 *
2115 * Open-counting is needed for pty masters, as well as for keeping
2116 * track of serial lines: DTR is dropped when the last close happens.
2117 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2118 *
2119 * The termios state of a pty is reset on first open so that
2120 * settings don't persist across reuse.
2121 *
2122 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2123 * tty->count should protect the rest.
2124 * ->siglock protects ->signal/->sighand
2125 *
2126 * Note: the tty_unlock/lock cases without a ref are only safe due to
2127 * tty_mutex
2128 */
2129
2130static int tty_open(struct inode *inode, struct file *filp)
2131{
2132 struct tty_struct *tty;
2133 int noctty, retval;
2134 dev_t device = inode->i_rdev;
2135 unsigned saved_flags = filp->f_flags;
2136
2137 nonseekable_open(inode, filp);
2138
2139retry_open:
2140 retval = tty_alloc_file(filp);
2141 if (retval)
2142 return -ENOMEM;
2143
2144 tty = tty_open_current_tty(device, filp);
2145 if (!tty)
2146 tty = tty_open_by_driver(device, filp);
2147
2148 if (IS_ERR(tty)) {
2149 tty_free_file(filp);
2150 retval = PTR_ERR(tty);
2151 if (retval != -EAGAIN || signal_pending(current))
2152 return retval;
2153 schedule();
2154 goto retry_open;
2155 }
2156
2157 tty_add_file(tty, filp);
2158
2159 check_tty_count(tty, __func__);
2160 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2161
2162 if (tty->ops->open)
2163 retval = tty->ops->open(tty, filp);
2164 else
2165 retval = -ENODEV;
2166 filp->f_flags = saved_flags;
2167
2168 if (retval) {
2169 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2170
2171 tty_unlock(tty); /* need to call tty_release without BTM */
2172 tty_release(inode, filp);
2173 if (retval != -ERESTARTSYS)
2174 return retval;
2175
2176 if (signal_pending(current))
2177 return retval;
2178
2179 schedule();
2180 /*
2181 * Need to reset f_op in case a hangup happened.
2182 */
2183 if (tty_hung_up_p(filp))
2184 filp->f_op = &tty_fops;
2185 goto retry_open;
2186 }
2187 clear_bit(TTY_HUPPED, &tty->flags);
2188
2189 noctty = (filp->f_flags & O_NOCTTY) ||
2190 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2191 device == MKDEV(TTYAUX_MAJOR, 1) ||
2192 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2193 tty->driver->subtype == PTY_TYPE_MASTER);
2194 if (!noctty)
2195 tty_open_proc_set_tty(filp, tty);
2196 tty_unlock(tty);
2197 return 0;
2198}
2199
2200
2201
2202/**
2203 * tty_poll - check tty status
2204 * @filp: file being polled
2205 * @wait: poll wait structures to update
2206 *
2207 * Call the line discipline polling method to obtain the poll
2208 * status of the device.
2209 *
2210 * Locking: locks called line discipline but ldisc poll method
2211 * may be re-entered freely by other callers.
2212 */
2213
2214static __poll_t tty_poll(struct file *filp, poll_table *wait)
2215{
2216 struct tty_struct *tty = file_tty(filp);
2217 struct tty_ldisc *ld;
2218 __poll_t ret = 0;
2219
2220 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2221 return 0;
2222
2223 ld = tty_ldisc_ref_wait(tty);
2224 if (!ld)
2225 return hung_up_tty_poll(filp, wait);
2226 if (ld->ops->poll)
2227 ret = ld->ops->poll(tty, filp, wait);
2228 tty_ldisc_deref(ld);
2229 return ret;
2230}
2231
2232static int __tty_fasync(int fd, struct file *filp, int on)
2233{
2234 struct tty_struct *tty = file_tty(filp);
2235 unsigned long flags;
2236 int retval = 0;
2237
2238 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2239 goto out;
2240
2241 retval = fasync_helper(fd, filp, on, &tty->fasync);
2242 if (retval <= 0)
2243 goto out;
2244
2245 if (on) {
2246 enum pid_type type;
2247 struct pid *pid;
2248
2249 spin_lock_irqsave(&tty->ctrl.lock, flags);
2250 if (tty->ctrl.pgrp) {
2251 pid = tty->ctrl.pgrp;
2252 type = PIDTYPE_PGID;
2253 } else {
2254 pid = task_pid(current);
2255 type = PIDTYPE_TGID;
2256 }
2257 get_pid(pid);
2258 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
2259 __f_setown(filp, pid, type, 0);
2260 put_pid(pid);
2261 retval = 0;
2262 }
2263out:
2264 return retval;
2265}
2266
2267static int tty_fasync(int fd, struct file *filp, int on)
2268{
2269 struct tty_struct *tty = file_tty(filp);
2270 int retval = -ENOTTY;
2271
2272 tty_lock(tty);
2273 if (!tty_hung_up_p(filp))
2274 retval = __tty_fasync(fd, filp, on);
2275 tty_unlock(tty);
2276
2277 return retval;
2278}
2279
2280/**
2281 * tiocsti - fake input character
2282 * @tty: tty to fake input into
2283 * @p: pointer to character
2284 *
2285 * Fake input to a tty device. Does the necessary locking and
2286 * input management.
2287 *
2288 * FIXME: does not honour flow control ??
2289 *
2290 * Locking:
2291 * Called functions take tty_ldiscs_lock
2292 * current->signal->tty check is safe without locks
2293 */
2294
2295static int tiocsti(struct tty_struct *tty, char __user *p)
2296{
2297 char ch, mbz = 0;
2298 struct tty_ldisc *ld;
2299
2300 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2301 return -EPERM;
2302 if (get_user(ch, p))
2303 return -EFAULT;
2304 tty_audit_tiocsti(tty, ch);
2305 ld = tty_ldisc_ref_wait(tty);
2306 if (!ld)
2307 return -EIO;
2308 tty_buffer_lock_exclusive(tty->port);
2309 if (ld->ops->receive_buf)
2310 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2311 tty_buffer_unlock_exclusive(tty->port);
2312 tty_ldisc_deref(ld);
2313 return 0;
2314}
2315
2316/**
2317 * tiocgwinsz - implement window query ioctl
2318 * @tty: tty
2319 * @arg: user buffer for result
2320 *
2321 * Copies the kernel idea of the window size into the user buffer.
2322 *
2323 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2324 * is consistent.
2325 */
2326
2327static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2328{
2329 int err;
2330
2331 mutex_lock(&tty->winsize_mutex);
2332 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2333 mutex_unlock(&tty->winsize_mutex);
2334
2335 return err ? -EFAULT : 0;
2336}
2337
2338/**
2339 * tty_do_resize - resize event
2340 * @tty: tty being resized
2341 * @ws: new dimensions
2342 *
2343 * Update the termios variables and send the necessary signals to
2344 * peform a terminal resize correctly
2345 */
2346
2347int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2348{
2349 struct pid *pgrp;
2350
2351 /* Lock the tty */
2352 mutex_lock(&tty->winsize_mutex);
2353 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2354 goto done;
2355
2356 /* Signal the foreground process group */
2357 pgrp = tty_get_pgrp(tty);
2358 if (pgrp)
2359 kill_pgrp(pgrp, SIGWINCH, 1);
2360 put_pid(pgrp);
2361
2362 tty->winsize = *ws;
2363done:
2364 mutex_unlock(&tty->winsize_mutex);
2365 return 0;
2366}
2367EXPORT_SYMBOL(tty_do_resize);
2368
2369/**
2370 * tiocswinsz - implement window size set ioctl
2371 * @tty: tty side of tty
2372 * @arg: user buffer for result
2373 *
2374 * Copies the user idea of the window size to the kernel. Traditionally
2375 * this is just advisory information but for the Linux console it
2376 * actually has driver level meaning and triggers a VC resize.
2377 *
2378 * Locking:
2379 * Driver dependent. The default do_resize method takes the
2380 * tty termios mutex and ctrl.lock. The console takes its own lock
2381 * then calls into the default method.
2382 */
2383
2384static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2385{
2386 struct winsize tmp_ws;
2387
2388 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2389 return -EFAULT;
2390
2391 if (tty->ops->resize)
2392 return tty->ops->resize(tty, &tmp_ws);
2393 else
2394 return tty_do_resize(tty, &tmp_ws);
2395}
2396
2397/**
2398 * tioccons - allow admin to move logical console
2399 * @file: the file to become console
2400 *
2401 * Allow the administrator to move the redirected console device
2402 *
2403 * Locking: uses redirect_lock to guard the redirect information
2404 */
2405
2406static int tioccons(struct file *file)
2407{
2408 if (!capable(CAP_SYS_ADMIN))
2409 return -EPERM;
2410 if (file->f_op->write_iter == redirected_tty_write) {
2411 struct file *f;
2412
2413 spin_lock(&redirect_lock);
2414 f = redirect;
2415 redirect = NULL;
2416 spin_unlock(&redirect_lock);
2417 if (f)
2418 fput(f);
2419 return 0;
2420 }
2421 if (file->f_op->write_iter != tty_write)
2422 return -ENOTTY;
2423 if (!(file->f_mode & FMODE_WRITE))
2424 return -EBADF;
2425 if (!(file->f_mode & FMODE_CAN_WRITE))
2426 return -EINVAL;
2427 spin_lock(&redirect_lock);
2428 if (redirect) {
2429 spin_unlock(&redirect_lock);
2430 return -EBUSY;
2431 }
2432 redirect = get_file(file);
2433 spin_unlock(&redirect_lock);
2434 return 0;
2435}
2436
2437/**
2438 * tiocsetd - set line discipline
2439 * @tty: tty device
2440 * @p: pointer to user data
2441 *
2442 * Set the line discipline according to user request.
2443 *
2444 * Locking: see tty_set_ldisc, this function is just a helper
2445 */
2446
2447static int tiocsetd(struct tty_struct *tty, int __user *p)
2448{
2449 int disc;
2450 int ret;
2451
2452 if (get_user(disc, p))
2453 return -EFAULT;
2454
2455 ret = tty_set_ldisc(tty, disc);
2456
2457 return ret;
2458}
2459
2460/**
2461 * tiocgetd - get line discipline
2462 * @tty: tty device
2463 * @p: pointer to user data
2464 *
2465 * Retrieves the line discipline id directly from the ldisc.
2466 *
2467 * Locking: waits for ldisc reference (in case the line discipline
2468 * is changing or the tty is being hungup)
2469 */
2470
2471static int tiocgetd(struct tty_struct *tty, int __user *p)
2472{
2473 struct tty_ldisc *ld;
2474 int ret;
2475
2476 ld = tty_ldisc_ref_wait(tty);
2477 if (!ld)
2478 return -EIO;
2479 ret = put_user(ld->ops->num, p);
2480 tty_ldisc_deref(ld);
2481 return ret;
2482}
2483
2484/**
2485 * send_break - performed time break
2486 * @tty: device to break on
2487 * @duration: timeout in mS
2488 *
2489 * Perform a timed break on hardware that lacks its own driver level
2490 * timed break functionality.
2491 *
2492 * Locking:
2493 * atomic_write_lock serializes
2494 *
2495 */
2496
2497static int send_break(struct tty_struct *tty, unsigned int duration)
2498{
2499 int retval;
2500
2501 if (tty->ops->break_ctl == NULL)
2502 return 0;
2503
2504 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2505 retval = tty->ops->break_ctl(tty, duration);
2506 else {
2507 /* Do the work ourselves */
2508 if (tty_write_lock(tty, 0) < 0)
2509 return -EINTR;
2510 retval = tty->ops->break_ctl(tty, -1);
2511 if (retval)
2512 goto out;
2513 if (!signal_pending(current))
2514 msleep_interruptible(duration);
2515 retval = tty->ops->break_ctl(tty, 0);
2516out:
2517 tty_write_unlock(tty);
2518 if (signal_pending(current))
2519 retval = -EINTR;
2520 }
2521 return retval;
2522}
2523
2524/**
2525 * tty_tiocmget - get modem status
2526 * @tty: tty device
2527 * @p: pointer to result
2528 *
2529 * Obtain the modem status bits from the tty driver if the feature
2530 * is supported. Return -ENOTTY if it is not available.
2531 *
2532 * Locking: none (up to the driver)
2533 */
2534
2535static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2536{
2537 int retval = -ENOTTY;
2538
2539 if (tty->ops->tiocmget) {
2540 retval = tty->ops->tiocmget(tty);
2541
2542 if (retval >= 0)
2543 retval = put_user(retval, p);
2544 }
2545 return retval;
2546}
2547
2548/**
2549 * tty_tiocmset - set modem status
2550 * @tty: tty device
2551 * @cmd: command - clear bits, set bits or set all
2552 * @p: pointer to desired bits
2553 *
2554 * Set the modem status bits from the tty driver if the feature
2555 * is supported. Return -ENOTTY if it is not available.
2556 *
2557 * Locking: none (up to the driver)
2558 */
2559
2560static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2561 unsigned __user *p)
2562{
2563 int retval;
2564 unsigned int set, clear, val;
2565
2566 if (tty->ops->tiocmset == NULL)
2567 return -ENOTTY;
2568
2569 retval = get_user(val, p);
2570 if (retval)
2571 return retval;
2572 set = clear = 0;
2573 switch (cmd) {
2574 case TIOCMBIS:
2575 set = val;
2576 break;
2577 case TIOCMBIC:
2578 clear = val;
2579 break;
2580 case TIOCMSET:
2581 set = val;
2582 clear = ~val;
2583 break;
2584 }
2585 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2586 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2587 return tty->ops->tiocmset(tty, set, clear);
2588}
2589
2590/**
2591 * tty_get_icount - get tty statistics
2592 * @tty: tty device
2593 * @icount: output parameter
2594 *
2595 * Gets a copy of the tty's icount statistics.
2596 *
2597 * Locking: none (up to the driver)
2598 */
2599int tty_get_icount(struct tty_struct *tty,
2600 struct serial_icounter_struct *icount)
2601{
2602 memset(icount, 0, sizeof(*icount));
2603
2604 if (tty->ops->get_icount)
2605 return tty->ops->get_icount(tty, icount);
2606 else
2607 return -ENOTTY;
2608}
2609EXPORT_SYMBOL_GPL(tty_get_icount);
2610
2611static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2612{
2613 struct serial_icounter_struct icount;
2614 int retval;
2615
2616 retval = tty_get_icount(tty, &icount);
2617 if (retval != 0)
2618 return retval;
2619
2620 if (copy_to_user(arg, &icount, sizeof(icount)))
2621 return -EFAULT;
2622 return 0;
2623}
2624
2625static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss)
2626{
2627 char comm[TASK_COMM_LEN];
2628 int flags;
2629
2630 flags = ss->flags & ASYNC_DEPRECATED;
2631
2632 if (flags)
2633 pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2634 __func__, get_task_comm(comm, current), flags);
2635
2636 if (!tty->ops->set_serial)
2637 return -ENOTTY;
2638
2639 return tty->ops->set_serial(tty, ss);
2640}
2641
2642static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2643{
2644 struct serial_struct v;
2645
2646 if (copy_from_user(&v, ss, sizeof(*ss)))
2647 return -EFAULT;
2648
2649 return tty_set_serial(tty, &v);
2650}
2651
2652static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2653{
2654 struct serial_struct v;
2655 int err;
2656
2657 memset(&v, 0, sizeof(v));
2658 if (!tty->ops->get_serial)
2659 return -ENOTTY;
2660 err = tty->ops->get_serial(tty, &v);
2661 if (!err && copy_to_user(ss, &v, sizeof(v)))
2662 err = -EFAULT;
2663 return err;
2664}
2665
2666/*
2667 * if pty, return the slave side (real_tty)
2668 * otherwise, return self
2669 */
2670static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2671{
2672 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2673 tty->driver->subtype == PTY_TYPE_MASTER)
2674 tty = tty->link;
2675 return tty;
2676}
2677
2678/*
2679 * Split this up, as gcc can choke on it otherwise..
2680 */
2681long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2682{
2683 struct tty_struct *tty = file_tty(file);
2684 struct tty_struct *real_tty;
2685 void __user *p = (void __user *)arg;
2686 int retval;
2687 struct tty_ldisc *ld;
2688
2689 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2690 return -EINVAL;
2691
2692 real_tty = tty_pair_get_tty(tty);
2693
2694 /*
2695 * Factor out some common prep work
2696 */
2697 switch (cmd) {
2698 case TIOCSETD:
2699 case TIOCSBRK:
2700 case TIOCCBRK:
2701 case TCSBRK:
2702 case TCSBRKP:
2703 retval = tty_check_change(tty);
2704 if (retval)
2705 return retval;
2706 if (cmd != TIOCCBRK) {
2707 tty_wait_until_sent(tty, 0);
2708 if (signal_pending(current))
2709 return -EINTR;
2710 }
2711 break;
2712 }
2713
2714 /*
2715 * Now do the stuff.
2716 */
2717 switch (cmd) {
2718 case TIOCSTI:
2719 return tiocsti(tty, p);
2720 case TIOCGWINSZ:
2721 return tiocgwinsz(real_tty, p);
2722 case TIOCSWINSZ:
2723 return tiocswinsz(real_tty, p);
2724 case TIOCCONS:
2725 return real_tty != tty ? -EINVAL : tioccons(file);
2726 case TIOCEXCL:
2727 set_bit(TTY_EXCLUSIVE, &tty->flags);
2728 return 0;
2729 case TIOCNXCL:
2730 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2731 return 0;
2732 case TIOCGEXCL:
2733 {
2734 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2735
2736 return put_user(excl, (int __user *)p);
2737 }
2738 case TIOCGETD:
2739 return tiocgetd(tty, p);
2740 case TIOCSETD:
2741 return tiocsetd(tty, p);
2742 case TIOCVHANGUP:
2743 if (!capable(CAP_SYS_ADMIN))
2744 return -EPERM;
2745 tty_vhangup(tty);
2746 return 0;
2747 case TIOCGDEV:
2748 {
2749 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2750
2751 return put_user(ret, (unsigned int __user *)p);
2752 }
2753 /*
2754 * Break handling
2755 */
2756 case TIOCSBRK: /* Turn break on, unconditionally */
2757 if (tty->ops->break_ctl)
2758 return tty->ops->break_ctl(tty, -1);
2759 return 0;
2760 case TIOCCBRK: /* Turn break off, unconditionally */
2761 if (tty->ops->break_ctl)
2762 return tty->ops->break_ctl(tty, 0);
2763 return 0;
2764 case TCSBRK: /* SVID version: non-zero arg --> no break */
2765 /* non-zero arg means wait for all output data
2766 * to be sent (performed above) but don't send break.
2767 * This is used by the tcdrain() termios function.
2768 */
2769 if (!arg)
2770 return send_break(tty, 250);
2771 return 0;
2772 case TCSBRKP: /* support for POSIX tcsendbreak() */
2773 return send_break(tty, arg ? arg*100 : 250);
2774
2775 case TIOCMGET:
2776 return tty_tiocmget(tty, p);
2777 case TIOCMSET:
2778 case TIOCMBIC:
2779 case TIOCMBIS:
2780 return tty_tiocmset(tty, cmd, p);
2781 case TIOCGICOUNT:
2782 return tty_tiocgicount(tty, p);
2783 case TCFLSH:
2784 switch (arg) {
2785 case TCIFLUSH:
2786 case TCIOFLUSH:
2787 /* flush tty buffer and allow ldisc to process ioctl */
2788 tty_buffer_flush(tty, NULL);
2789 break;
2790 }
2791 break;
2792 case TIOCSSERIAL:
2793 return tty_tiocsserial(tty, p);
2794 case TIOCGSERIAL:
2795 return tty_tiocgserial(tty, p);
2796 case TIOCGPTPEER:
2797 /* Special because the struct file is needed */
2798 return ptm_open_peer(file, tty, (int)arg);
2799 default:
2800 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2801 if (retval != -ENOIOCTLCMD)
2802 return retval;
2803 }
2804 if (tty->ops->ioctl) {
2805 retval = tty->ops->ioctl(tty, cmd, arg);
2806 if (retval != -ENOIOCTLCMD)
2807 return retval;
2808 }
2809 ld = tty_ldisc_ref_wait(tty);
2810 if (!ld)
2811 return hung_up_tty_ioctl(file, cmd, arg);
2812 retval = -EINVAL;
2813 if (ld->ops->ioctl) {
2814 retval = ld->ops->ioctl(tty, file, cmd, arg);
2815 if (retval == -ENOIOCTLCMD)
2816 retval = -ENOTTY;
2817 }
2818 tty_ldisc_deref(ld);
2819 return retval;
2820}
2821
2822#ifdef CONFIG_COMPAT
2823
2824struct serial_struct32 {
2825 compat_int_t type;
2826 compat_int_t line;
2827 compat_uint_t port;
2828 compat_int_t irq;
2829 compat_int_t flags;
2830 compat_int_t xmit_fifo_size;
2831 compat_int_t custom_divisor;
2832 compat_int_t baud_base;
2833 unsigned short close_delay;
2834 char io_type;
2835 char reserved_char;
2836 compat_int_t hub6;
2837 unsigned short closing_wait; /* time to wait before closing */
2838 unsigned short closing_wait2; /* no longer used... */
2839 compat_uint_t iomem_base;
2840 unsigned short iomem_reg_shift;
2841 unsigned int port_high;
2842 /* compat_ulong_t iomap_base FIXME */
2843 compat_int_t reserved;
2844};
2845
2846static int compat_tty_tiocsserial(struct tty_struct *tty,
2847 struct serial_struct32 __user *ss)
2848{
2849 struct serial_struct32 v32;
2850 struct serial_struct v;
2851
2852 if (copy_from_user(&v32, ss, sizeof(*ss)))
2853 return -EFAULT;
2854
2855 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2856 v.iomem_base = compat_ptr(v32.iomem_base);
2857 v.iomem_reg_shift = v32.iomem_reg_shift;
2858 v.port_high = v32.port_high;
2859 v.iomap_base = 0;
2860
2861 return tty_set_serial(tty, &v);
2862}
2863
2864static int compat_tty_tiocgserial(struct tty_struct *tty,
2865 struct serial_struct32 __user *ss)
2866{
2867 struct serial_struct32 v32;
2868 struct serial_struct v;
2869 int err;
2870
2871 memset(&v, 0, sizeof(v));
2872 memset(&v32, 0, sizeof(v32));
2873
2874 if (!tty->ops->get_serial)
2875 return -ENOTTY;
2876 err = tty->ops->get_serial(tty, &v);
2877 if (!err) {
2878 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2879 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2880 0xfffffff : ptr_to_compat(v.iomem_base);
2881 v32.iomem_reg_shift = v.iomem_reg_shift;
2882 v32.port_high = v.port_high;
2883 if (copy_to_user(ss, &v32, sizeof(v32)))
2884 err = -EFAULT;
2885 }
2886 return err;
2887}
2888static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2889 unsigned long arg)
2890{
2891 struct tty_struct *tty = file_tty(file);
2892 struct tty_ldisc *ld;
2893 int retval = -ENOIOCTLCMD;
2894
2895 switch (cmd) {
2896 case TIOCOUTQ:
2897 case TIOCSTI:
2898 case TIOCGWINSZ:
2899 case TIOCSWINSZ:
2900 case TIOCGEXCL:
2901 case TIOCGETD:
2902 case TIOCSETD:
2903 case TIOCGDEV:
2904 case TIOCMGET:
2905 case TIOCMSET:
2906 case TIOCMBIC:
2907 case TIOCMBIS:
2908 case TIOCGICOUNT:
2909 case TIOCGPGRP:
2910 case TIOCSPGRP:
2911 case TIOCGSID:
2912 case TIOCSERGETLSR:
2913 case TIOCGRS485:
2914 case TIOCSRS485:
2915#ifdef TIOCGETP
2916 case TIOCGETP:
2917 case TIOCSETP:
2918 case TIOCSETN:
2919#endif
2920#ifdef TIOCGETC
2921 case TIOCGETC:
2922 case TIOCSETC:
2923#endif
2924#ifdef TIOCGLTC
2925 case TIOCGLTC:
2926 case TIOCSLTC:
2927#endif
2928 case TCSETSF:
2929 case TCSETSW:
2930 case TCSETS:
2931 case TCGETS:
2932#ifdef TCGETS2
2933 case TCGETS2:
2934 case TCSETSF2:
2935 case TCSETSW2:
2936 case TCSETS2:
2937#endif
2938 case TCGETA:
2939 case TCSETAF:
2940 case TCSETAW:
2941 case TCSETA:
2942 case TIOCGLCKTRMIOS:
2943 case TIOCSLCKTRMIOS:
2944#ifdef TCGETX
2945 case TCGETX:
2946 case TCSETX:
2947 case TCSETXW:
2948 case TCSETXF:
2949#endif
2950 case TIOCGSOFTCAR:
2951 case TIOCSSOFTCAR:
2952
2953 case PPPIOCGCHAN:
2954 case PPPIOCGUNIT:
2955 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2956 case TIOCCONS:
2957 case TIOCEXCL:
2958 case TIOCNXCL:
2959 case TIOCVHANGUP:
2960 case TIOCSBRK:
2961 case TIOCCBRK:
2962 case TCSBRK:
2963 case TCSBRKP:
2964 case TCFLSH:
2965 case TIOCGPTPEER:
2966 case TIOCNOTTY:
2967 case TIOCSCTTY:
2968 case TCXONC:
2969 case TIOCMIWAIT:
2970 case TIOCSERCONFIG:
2971 return tty_ioctl(file, cmd, arg);
2972 }
2973
2974 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2975 return -EINVAL;
2976
2977 switch (cmd) {
2978 case TIOCSSERIAL:
2979 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2980 case TIOCGSERIAL:
2981 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2982 }
2983 if (tty->ops->compat_ioctl) {
2984 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2985 if (retval != -ENOIOCTLCMD)
2986 return retval;
2987 }
2988
2989 ld = tty_ldisc_ref_wait(tty);
2990 if (!ld)
2991 return hung_up_tty_compat_ioctl(file, cmd, arg);
2992 if (ld->ops->compat_ioctl)
2993 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2994 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2995 retval = ld->ops->ioctl(tty, file,
2996 (unsigned long)compat_ptr(cmd), arg);
2997 tty_ldisc_deref(ld);
2998
2999 return retval;
3000}
3001#endif
3002
3003static int this_tty(const void *t, struct file *file, unsigned fd)
3004{
3005 if (likely(file->f_op->read_iter != tty_read))
3006 return 0;
3007 return file_tty(file) != t ? 0 : fd + 1;
3008}
3009
3010/*
3011 * This implements the "Secure Attention Key" --- the idea is to
3012 * prevent trojan horses by killing all processes associated with this
3013 * tty when the user hits the "Secure Attention Key". Required for
3014 * super-paranoid applications --- see the Orange Book for more details.
3015 *
3016 * This code could be nicer; ideally it should send a HUP, wait a few
3017 * seconds, then send a INT, and then a KILL signal. But you then
3018 * have to coordinate with the init process, since all processes associated
3019 * with the current tty must be dead before the new getty is allowed
3020 * to spawn.
3021 *
3022 * Now, if it would be correct ;-/ The current code has a nasty hole -
3023 * it doesn't catch files in flight. We may send the descriptor to ourselves
3024 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3025 *
3026 * Nasty bug: do_SAK is being called in interrupt context. This can
3027 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3028 */
3029void __do_SAK(struct tty_struct *tty)
3030{
3031#ifdef TTY_SOFT_SAK
3032 tty_hangup(tty);
3033#else
3034 struct task_struct *g, *p;
3035 struct pid *session;
3036 int i;
3037 unsigned long flags;
3038
3039 if (!tty)
3040 return;
3041
3042 spin_lock_irqsave(&tty->ctrl.lock, flags);
3043 session = get_pid(tty->ctrl.session);
3044 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
3045
3046 tty_ldisc_flush(tty);
3047
3048 tty_driver_flush_buffer(tty);
3049
3050 read_lock(&tasklist_lock);
3051 /* Kill the entire session */
3052 do_each_pid_task(session, PIDTYPE_SID, p) {
3053 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3054 task_pid_nr(p), p->comm);
3055 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3056 } while_each_pid_task(session, PIDTYPE_SID, p);
3057
3058 /* Now kill any processes that happen to have the tty open */
3059 do_each_thread(g, p) {
3060 if (p->signal->tty == tty) {
3061 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3062 task_pid_nr(p), p->comm);
3063 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3064 continue;
3065 }
3066 task_lock(p);
3067 i = iterate_fd(p->files, 0, this_tty, tty);
3068 if (i != 0) {
3069 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3070 task_pid_nr(p), p->comm, i - 1);
3071 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3072 }
3073 task_unlock(p);
3074 } while_each_thread(g, p);
3075 read_unlock(&tasklist_lock);
3076 put_pid(session);
3077#endif
3078}
3079
3080static void do_SAK_work(struct work_struct *work)
3081{
3082 struct tty_struct *tty =
3083 container_of(work, struct tty_struct, SAK_work);
3084 __do_SAK(tty);
3085}
3086
3087/*
3088 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3089 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3090 * the values which we write to it will be identical to the values which it
3091 * already has. --akpm
3092 */
3093void do_SAK(struct tty_struct *tty)
3094{
3095 if (!tty)
3096 return;
3097 schedule_work(&tty->SAK_work);
3098}
3099EXPORT_SYMBOL(do_SAK);
3100
3101/* Must put_device() after it's unused! */
3102static struct device *tty_get_device(struct tty_struct *tty)
3103{
3104 dev_t devt = tty_devnum(tty);
3105
3106 return class_find_device_by_devt(tty_class, devt);
3107}
3108
3109
3110/*
3111 * alloc_tty_struct
3112 *
3113 * This subroutine allocates and initializes a tty structure.
3114 *
3115 * Locking: none - tty in question is not exposed at this point
3116 */
3117
3118struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3119{
3120 struct tty_struct *tty;
3121
3122 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3123 if (!tty)
3124 return NULL;
3125
3126 kref_init(&tty->kref);
3127 tty->magic = TTY_MAGIC;
3128 if (tty_ldisc_init(tty)) {
3129 kfree(tty);
3130 return NULL;
3131 }
3132 tty->ctrl.session = NULL;
3133 tty->ctrl.pgrp = NULL;
3134 mutex_init(&tty->legacy_mutex);
3135 mutex_init(&tty->throttle_mutex);
3136 init_rwsem(&tty->termios_rwsem);
3137 mutex_init(&tty->winsize_mutex);
3138 init_ldsem(&tty->ldisc_sem);
3139 init_waitqueue_head(&tty->write_wait);
3140 init_waitqueue_head(&tty->read_wait);
3141 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3142 mutex_init(&tty->atomic_write_lock);
3143 spin_lock_init(&tty->ctrl.lock);
3144 spin_lock_init(&tty->flow.lock);
3145 spin_lock_init(&tty->files_lock);
3146 INIT_LIST_HEAD(&tty->tty_files);
3147 INIT_WORK(&tty->SAK_work, do_SAK_work);
3148
3149 tty->driver = driver;
3150 tty->ops = driver->ops;
3151 tty->index = idx;
3152 tty_line_name(driver, idx, tty->name);
3153 tty->dev = tty_get_device(tty);
3154
3155 return tty;
3156}
3157
3158/**
3159 * tty_put_char - write one character to a tty
3160 * @tty: tty
3161 * @ch: character
3162 *
3163 * Write one byte to the tty using the provided put_char method
3164 * if present. Returns the number of characters successfully output.
3165 *
3166 * Note: the specific put_char operation in the driver layer may go
3167 * away soon. Don't call it directly, use this method
3168 */
3169
3170int tty_put_char(struct tty_struct *tty, unsigned char ch)
3171{
3172 if (tty->ops->put_char)
3173 return tty->ops->put_char(tty, ch);
3174 return tty->ops->write(tty, &ch, 1);
3175}
3176EXPORT_SYMBOL_GPL(tty_put_char);
3177
3178struct class *tty_class;
3179
3180static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3181 unsigned int index, unsigned int count)
3182{
3183 int err;
3184
3185 /* init here, since reused cdevs cause crashes */
3186 driver->cdevs[index] = cdev_alloc();
3187 if (!driver->cdevs[index])
3188 return -ENOMEM;
3189 driver->cdevs[index]->ops = &tty_fops;
3190 driver->cdevs[index]->owner = driver->owner;
3191 err = cdev_add(driver->cdevs[index], dev, count);
3192 if (err)
3193 kobject_put(&driver->cdevs[index]->kobj);
3194 return err;
3195}
3196
3197/**
3198 * tty_register_device - register a tty device
3199 * @driver: the tty driver that describes the tty device
3200 * @index: the index in the tty driver for this tty device
3201 * @device: a struct device that is associated with this tty device.
3202 * This field is optional, if there is no known struct device
3203 * for this tty device it can be set to NULL safely.
3204 *
3205 * Returns a pointer to the struct device for this tty device
3206 * (or ERR_PTR(-EFOO) on error).
3207 *
3208 * This call is required to be made to register an individual tty device
3209 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3210 * that bit is not set, this function should not be called by a tty
3211 * driver.
3212 *
3213 * Locking: ??
3214 */
3215
3216struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3217 struct device *device)
3218{
3219 return tty_register_device_attr(driver, index, device, NULL, NULL);
3220}
3221EXPORT_SYMBOL(tty_register_device);
3222
3223static void tty_device_create_release(struct device *dev)
3224{
3225 dev_dbg(dev, "releasing...\n");
3226 kfree(dev);
3227}
3228
3229/**
3230 * tty_register_device_attr - register a tty device
3231 * @driver: the tty driver that describes the tty device
3232 * @index: the index in the tty driver for this tty device
3233 * @device: a struct device that is associated with this tty device.
3234 * This field is optional, if there is no known struct device
3235 * for this tty device it can be set to NULL safely.
3236 * @drvdata: Driver data to be set to device.
3237 * @attr_grp: Attribute group to be set on device.
3238 *
3239 * Returns a pointer to the struct device for this tty device
3240 * (or ERR_PTR(-EFOO) on error).
3241 *
3242 * This call is required to be made to register an individual tty device
3243 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3244 * that bit is not set, this function should not be called by a tty
3245 * driver.
3246 *
3247 * Locking: ??
3248 */
3249struct device *tty_register_device_attr(struct tty_driver *driver,
3250 unsigned index, struct device *device,
3251 void *drvdata,
3252 const struct attribute_group **attr_grp)
3253{
3254 char name[64];
3255 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3256 struct ktermios *tp;
3257 struct device *dev;
3258 int retval;
3259
3260 if (index >= driver->num) {
3261 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3262 driver->name, index);
3263 return ERR_PTR(-EINVAL);
3264 }
3265
3266 if (driver->type == TTY_DRIVER_TYPE_PTY)
3267 pty_line_name(driver, index, name);
3268 else
3269 tty_line_name(driver, index, name);
3270
3271 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3272 if (!dev)
3273 return ERR_PTR(-ENOMEM);
3274
3275 dev->devt = devt;
3276 dev->class = tty_class;
3277 dev->parent = device;
3278 dev->release = tty_device_create_release;
3279 dev_set_name(dev, "%s", name);
3280 dev->groups = attr_grp;
3281 dev_set_drvdata(dev, drvdata);
3282
3283 dev_set_uevent_suppress(dev, 1);
3284
3285 retval = device_register(dev);
3286 if (retval)
3287 goto err_put;
3288
3289 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3290 /*
3291 * Free any saved termios data so that the termios state is
3292 * reset when reusing a minor number.
3293 */
3294 tp = driver->termios[index];
3295 if (tp) {
3296 driver->termios[index] = NULL;
3297 kfree(tp);
3298 }
3299
3300 retval = tty_cdev_add(driver, devt, index, 1);
3301 if (retval)
3302 goto err_del;
3303 }
3304
3305 dev_set_uevent_suppress(dev, 0);
3306 kobject_uevent(&dev->kobj, KOBJ_ADD);
3307
3308 return dev;
3309
3310err_del:
3311 device_del(dev);
3312err_put:
3313 put_device(dev);
3314
3315 return ERR_PTR(retval);
3316}
3317EXPORT_SYMBOL_GPL(tty_register_device_attr);
3318
3319/**
3320 * tty_unregister_device - unregister a tty device
3321 * @driver: the tty driver that describes the tty device
3322 * @index: the index in the tty driver for this tty device
3323 *
3324 * If a tty device is registered with a call to tty_register_device() then
3325 * this function must be called when the tty device is gone.
3326 *
3327 * Locking: ??
3328 */
3329
3330void tty_unregister_device(struct tty_driver *driver, unsigned index)
3331{
3332 device_destroy(tty_class,
3333 MKDEV(driver->major, driver->minor_start) + index);
3334 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3335 cdev_del(driver->cdevs[index]);
3336 driver->cdevs[index] = NULL;
3337 }
3338}
3339EXPORT_SYMBOL(tty_unregister_device);
3340
3341/**
3342 * __tty_alloc_driver -- allocate tty driver
3343 * @lines: count of lines this driver can handle at most
3344 * @owner: module which is responsible for this driver
3345 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3346 *
3347 * This should not be called directly, some of the provided macros should be
3348 * used instead. Use IS_ERR and friends on @retval.
3349 */
3350struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3351 unsigned long flags)
3352{
3353 struct tty_driver *driver;
3354 unsigned int cdevs = 1;
3355 int err;
3356
3357 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3358 return ERR_PTR(-EINVAL);
3359
3360 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
3361 if (!driver)
3362 return ERR_PTR(-ENOMEM);
3363
3364 kref_init(&driver->kref);
3365 driver->magic = TTY_DRIVER_MAGIC;
3366 driver->num = lines;
3367 driver->owner = owner;
3368 driver->flags = flags;
3369
3370 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3371 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3372 GFP_KERNEL);
3373 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3374 GFP_KERNEL);
3375 if (!driver->ttys || !driver->termios) {
3376 err = -ENOMEM;
3377 goto err_free_all;
3378 }
3379 }
3380
3381 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3382 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3383 GFP_KERNEL);
3384 if (!driver->ports) {
3385 err = -ENOMEM;
3386 goto err_free_all;
3387 }
3388 cdevs = lines;
3389 }
3390
3391 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3392 if (!driver->cdevs) {
3393 err = -ENOMEM;
3394 goto err_free_all;
3395 }
3396
3397 return driver;
3398err_free_all:
3399 kfree(driver->ports);
3400 kfree(driver->ttys);
3401 kfree(driver->termios);
3402 kfree(driver->cdevs);
3403 kfree(driver);
3404 return ERR_PTR(err);
3405}
3406EXPORT_SYMBOL(__tty_alloc_driver);
3407
3408static void destruct_tty_driver(struct kref *kref)
3409{
3410 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3411 int i;
3412 struct ktermios *tp;
3413
3414 if (driver->flags & TTY_DRIVER_INSTALLED) {
3415 for (i = 0; i < driver->num; i++) {
3416 tp = driver->termios[i];
3417 if (tp) {
3418 driver->termios[i] = NULL;
3419 kfree(tp);
3420 }
3421 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3422 tty_unregister_device(driver, i);
3423 }
3424 proc_tty_unregister_driver(driver);
3425 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3426 cdev_del(driver->cdevs[0]);
3427 }
3428 kfree(driver->cdevs);
3429 kfree(driver->ports);
3430 kfree(driver->termios);
3431 kfree(driver->ttys);
3432 kfree(driver);
3433}
3434
3435void tty_driver_kref_put(struct tty_driver *driver)
3436{
3437 kref_put(&driver->kref, destruct_tty_driver);
3438}
3439EXPORT_SYMBOL(tty_driver_kref_put);
3440
3441void tty_set_operations(struct tty_driver *driver,
3442 const struct tty_operations *op)
3443{
3444 driver->ops = op;
3445};
3446EXPORT_SYMBOL(tty_set_operations);
3447
3448void put_tty_driver(struct tty_driver *d)
3449{
3450 tty_driver_kref_put(d);
3451}
3452EXPORT_SYMBOL(put_tty_driver);
3453
3454/*
3455 * Called by a tty driver to register itself.
3456 */
3457int tty_register_driver(struct tty_driver *driver)
3458{
3459 int error;
3460 int i;
3461 dev_t dev;
3462 struct device *d;
3463
3464 if (!driver->major) {
3465 error = alloc_chrdev_region(&dev, driver->minor_start,
3466 driver->num, driver->name);
3467 if (!error) {
3468 driver->major = MAJOR(dev);
3469 driver->minor_start = MINOR(dev);
3470 }
3471 } else {
3472 dev = MKDEV(driver->major, driver->minor_start);
3473 error = register_chrdev_region(dev, driver->num, driver->name);
3474 }
3475 if (error < 0)
3476 goto err;
3477
3478 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3479 error = tty_cdev_add(driver, dev, 0, driver->num);
3480 if (error)
3481 goto err_unreg_char;
3482 }
3483
3484 mutex_lock(&tty_mutex);
3485 list_add(&driver->tty_drivers, &tty_drivers);
3486 mutex_unlock(&tty_mutex);
3487
3488 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3489 for (i = 0; i < driver->num; i++) {
3490 d = tty_register_device(driver, i, NULL);
3491 if (IS_ERR(d)) {
3492 error = PTR_ERR(d);
3493 goto err_unreg_devs;
3494 }
3495 }
3496 }
3497 proc_tty_register_driver(driver);
3498 driver->flags |= TTY_DRIVER_INSTALLED;
3499 return 0;
3500
3501err_unreg_devs:
3502 for (i--; i >= 0; i--)
3503 tty_unregister_device(driver, i);
3504
3505 mutex_lock(&tty_mutex);
3506 list_del(&driver->tty_drivers);
3507 mutex_unlock(&tty_mutex);
3508
3509err_unreg_char:
3510 unregister_chrdev_region(dev, driver->num);
3511err:
3512 return error;
3513}
3514EXPORT_SYMBOL(tty_register_driver);
3515
3516/*
3517 * Called by a tty driver to unregister itself.
3518 */
3519void tty_unregister_driver(struct tty_driver *driver)
3520{
3521 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3522 driver->num);
3523 mutex_lock(&tty_mutex);
3524 list_del(&driver->tty_drivers);
3525 mutex_unlock(&tty_mutex);
3526}
3527EXPORT_SYMBOL(tty_unregister_driver);
3528
3529dev_t tty_devnum(struct tty_struct *tty)
3530{
3531 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3532}
3533EXPORT_SYMBOL(tty_devnum);
3534
3535void tty_default_fops(struct file_operations *fops)
3536{
3537 *fops = tty_fops;
3538}
3539
3540static char *tty_devnode(struct device *dev, umode_t *mode)
3541{
3542 if (!mode)
3543 return NULL;
3544 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3545 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3546 *mode = 0666;
3547 return NULL;
3548}
3549
3550static int __init tty_class_init(void)
3551{
3552 tty_class = class_create(THIS_MODULE, "tty");
3553 if (IS_ERR(tty_class))
3554 return PTR_ERR(tty_class);
3555 tty_class->devnode = tty_devnode;
3556 return 0;
3557}
3558
3559postcore_initcall(tty_class_init);
3560
3561/* 3/2004 jmc: why do these devices exist? */
3562static struct cdev tty_cdev, console_cdev;
3563
3564static ssize_t show_cons_active(struct device *dev,
3565 struct device_attribute *attr, char *buf)
3566{
3567 struct console *cs[16];
3568 int i = 0;
3569 struct console *c;
3570 ssize_t count = 0;
3571
3572 console_lock();
3573 for_each_console(c) {
3574 if (!c->device)
3575 continue;
3576 if (!c->write)
3577 continue;
3578 if ((c->flags & CON_ENABLED) == 0)
3579 continue;
3580 cs[i++] = c;
3581 if (i >= ARRAY_SIZE(cs))
3582 break;
3583 }
3584 while (i--) {
3585 int index = cs[i]->index;
3586 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3587
3588 /* don't resolve tty0 as some programs depend on it */
3589 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3590 count += tty_line_name(drv, index, buf + count);
3591 else
3592 count += sprintf(buf + count, "%s%d",
3593 cs[i]->name, cs[i]->index);
3594
3595 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3596 }
3597 console_unlock();
3598
3599 return count;
3600}
3601static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3602
3603static struct attribute *cons_dev_attrs[] = {
3604 &dev_attr_active.attr,
3605 NULL
3606};
3607
3608ATTRIBUTE_GROUPS(cons_dev);
3609
3610static struct device *consdev;
3611
3612void console_sysfs_notify(void)
3613{
3614 if (consdev)
3615 sysfs_notify(&consdev->kobj, NULL, "active");
3616}
3617
3618/*
3619 * Ok, now we can initialize the rest of the tty devices and can count
3620 * on memory allocations, interrupts etc..
3621 */
3622int __init tty_init(void)
3623{
3624 tty_sysctl_init();
3625 cdev_init(&tty_cdev, &tty_fops);
3626 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3627 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3628 panic("Couldn't register /dev/tty driver\n");
3629 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3630
3631 cdev_init(&console_cdev, &console_fops);
3632 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3633 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3634 panic("Couldn't register /dev/console driver\n");
3635 consdev = device_create_with_groups(tty_class, NULL,
3636 MKDEV(TTYAUX_MAJOR, 1), NULL,
3637 cons_dev_groups, "console");
3638 if (IS_ERR(consdev))
3639 consdev = NULL;
3640
3641#ifdef CONFIG_VT
3642 vty_init(&console_fops);
3643#endif
3644 return 0;
3645}
3646