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