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