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