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