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