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