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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 */
5
6/*
7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
8 * or rs-channels. It also implements echoing, cooked mode etc.
9 *
10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 *
12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
13 * tty_struct and tty_queue structures. Previously there was an array
14 * of 256 tty_struct's which was statically allocated, and the
15 * tty_queue structures were allocated at boot time. Both are now
16 * dynamically allocated only when the tty is open.
17 *
18 * Also restructured routines so that there is more of a separation
19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
20 * the low-level tty routines (serial.c, pty.c, console.c). This
21 * makes for cleaner and more compact code. -TYT, 9/17/92
22 *
23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
24 * which can be dynamically activated and de-activated by the line
25 * discipline handling modules (like SLIP).
26 *
27 * NOTE: pay no attention to the line discipline code (yet); its
28 * interface is still subject to change in this version...
29 * -- TYT, 1/31/92
30 *
31 * Added functionality to the OPOST tty handling. No delays, but all
32 * other bits should be there.
33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 *
35 * Rewrote canonical mode and added more termios flags.
36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 *
38 * Reorganized FASYNC support so mouse code can share it.
39 * -- ctm@ardi.com, 9Sep95
40 *
41 * New TIOCLINUX variants added.
42 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 *
44 * Restrict vt switching via ioctl()
45 * -- grif@cs.ucr.edu, 5-Dec-95
46 *
47 * Move console and virtual terminal code to more appropriate files,
48 * implement CONFIG_VT and generalize console device interface.
49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 *
51 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
52 * -- Bill Hawes <whawes@star.net>, June 97
53 *
54 * Added devfs support.
55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 *
57 * Added support for a Unix98-style ptmx device.
58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 *
60 * Reduced memory usage for older ARM systems
61 * -- Russell King <rmk@arm.linux.org.uk>
62 *
63 * Move do_SAK() into process context. Less stack use in devfs functions.
64 * alloc_tty_struct() always uses kmalloc()
65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
66 */
67
68#include <linux/types.h>
69#include <linux/major.h>
70#include <linux/errno.h>
71#include <linux/signal.h>
72#include <linux/fcntl.h>
73#include <linux/sched/signal.h>
74#include <linux/sched/task.h>
75#include <linux/interrupt.h>
76#include <linux/tty.h>
77#include <linux/tty_driver.h>
78#include <linux/tty_flip.h>
79#include <linux/devpts_fs.h>
80#include <linux/file.h>
81#include <linux/fdtable.h>
82#include <linux/console.h>
83#include <linux/timer.h>
84#include <linux/ctype.h>
85#include <linux/kd.h>
86#include <linux/mm.h>
87#include <linux/string.h>
88#include <linux/slab.h>
89#include <linux/poll.h>
90#include <linux/proc_fs.h>
91#include <linux/init.h>
92#include <linux/module.h>
93#include <linux/device.h>
94#include <linux/wait.h>
95#include <linux/bitops.h>
96#include <linux/delay.h>
97#include <linux/seq_file.h>
98#include <linux/serial.h>
99#include <linux/ratelimit.h>
100
101#include <linux/uaccess.h>
102
103#include <linux/kbd_kern.h>
104#include <linux/vt_kern.h>
105#include <linux/selection.h>
106
107#include <linux/kmod.h>
108#include <linux/nsproxy.h>
109
110#undef TTY_DEBUG_HANGUP
111#ifdef TTY_DEBUG_HANGUP
112# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
113#else
114# define tty_debug_hangup(tty, f, args...) do { } while (0)
115#endif
116
117#define TTY_PARANOIA_CHECK 1
118#define CHECK_TTY_COUNT 1
119
120struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
121 .c_iflag = ICRNL | IXON,
122 .c_oflag = OPOST | ONLCR,
123 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
124 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
125 ECHOCTL | ECHOKE | IEXTEN,
126 .c_cc = INIT_C_CC,
127 .c_ispeed = 38400,
128 .c_ospeed = 38400,
129 /* .c_line = N_TTY, */
130};
131
132EXPORT_SYMBOL(tty_std_termios);
133
134/* This list gets poked at by procfs and various bits of boot up code. This
135 could do with some rationalisation such as pulling the tty proc function
136 into this file */
137
138LIST_HEAD(tty_drivers); /* linked list of tty drivers */
139
140/* Mutex to protect creating and releasing a tty */
141DEFINE_MUTEX(tty_mutex);
142
143static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
144static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
145ssize_t redirected_tty_write(struct file *, const char __user *,
146 size_t, loff_t *);
147static __poll_t tty_poll(struct file *, poll_table *);
148static int tty_open(struct inode *, struct file *);
149long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
150#ifdef CONFIG_COMPAT
151static long tty_compat_ioctl(struct file *file, unsigned int cmd,
152 unsigned long arg);
153#else
154#define tty_compat_ioctl NULL
155#endif
156static int __tty_fasync(int fd, struct file *filp, int on);
157static int tty_fasync(int fd, struct file *filp, int on);
158static void release_tty(struct tty_struct *tty, int idx);
159
160/**
161 * free_tty_struct - free a disused tty
162 * @tty: tty struct to free
163 *
164 * Free the write buffers, tty queue and tty memory itself.
165 *
166 * Locking: none. Must be called after tty is definitely unused
167 */
168
169static void free_tty_struct(struct tty_struct *tty)
170{
171 tty_ldisc_deinit(tty);
172 put_device(tty->dev);
173 kfree(tty->write_buf);
174 tty->magic = 0xDEADDEAD;
175 kfree(tty);
176}
177
178static inline struct tty_struct *file_tty(struct file *file)
179{
180 return ((struct tty_file_private *)file->private_data)->tty;
181}
182
183int tty_alloc_file(struct file *file)
184{
185 struct tty_file_private *priv;
186
187 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
188 if (!priv)
189 return -ENOMEM;
190
191 file->private_data = priv;
192
193 return 0;
194}
195
196/* Associate a new file with the tty structure */
197void tty_add_file(struct tty_struct *tty, struct file *file)
198{
199 struct tty_file_private *priv = file->private_data;
200
201 priv->tty = tty;
202 priv->file = file;
203
204 spin_lock(&tty->files_lock);
205 list_add(&priv->list, &tty->tty_files);
206 spin_unlock(&tty->files_lock);
207}
208
209/**
210 * tty_free_file - free file->private_data
211 *
212 * This shall be used only for fail path handling when tty_add_file was not
213 * called yet.
214 */
215void tty_free_file(struct file *file)
216{
217 struct tty_file_private *priv = file->private_data;
218
219 file->private_data = NULL;
220 kfree(priv);
221}
222
223/* Delete file from its tty */
224static void tty_del_file(struct file *file)
225{
226 struct tty_file_private *priv = file->private_data;
227 struct tty_struct *tty = priv->tty;
228
229 spin_lock(&tty->files_lock);
230 list_del(&priv->list);
231 spin_unlock(&tty->files_lock);
232 tty_free_file(file);
233}
234
235/**
236 * tty_name - return tty naming
237 * @tty: tty structure
238 *
239 * Convert a tty structure into a name. The name reflects the kernel
240 * naming policy and if udev is in use may not reflect user space
241 *
242 * Locking: none
243 */
244
245const char *tty_name(const struct tty_struct *tty)
246{
247 if (!tty) /* Hmm. NULL pointer. That's fun. */
248 return "NULL tty";
249 return tty->name;
250}
251
252EXPORT_SYMBOL(tty_name);
253
254const char *tty_driver_name(const struct tty_struct *tty)
255{
256 if (!tty || !tty->driver)
257 return "";
258 return tty->driver->name;
259}
260
261static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
262 const char *routine)
263{
264#ifdef TTY_PARANOIA_CHECK
265 if (!tty) {
266 pr_warn("(%d:%d): %s: NULL tty\n",
267 imajor(inode), iminor(inode), routine);
268 return 1;
269 }
270 if (tty->magic != TTY_MAGIC) {
271 pr_warn("(%d:%d): %s: bad magic number\n",
272 imajor(inode), iminor(inode), routine);
273 return 1;
274 }
275#endif
276 return 0;
277}
278
279/* Caller must hold tty_lock */
280static int check_tty_count(struct tty_struct *tty, const char *routine)
281{
282#ifdef CHECK_TTY_COUNT
283 struct list_head *p;
284 int count = 0, kopen_count = 0;
285
286 spin_lock(&tty->files_lock);
287 list_for_each(p, &tty->tty_files) {
288 count++;
289 }
290 spin_unlock(&tty->files_lock);
291 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
292 tty->driver->subtype == PTY_TYPE_SLAVE &&
293 tty->link && tty->link->count)
294 count++;
295 if (tty_port_kopened(tty->port))
296 kopen_count++;
297 if (tty->count != (count + kopen_count)) {
298 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
299 routine, tty->count, count, kopen_count);
300 return (count + kopen_count);
301 }
302#endif
303 return 0;
304}
305
306/**
307 * get_tty_driver - find device of a tty
308 * @dev_t: device identifier
309 * @index: returns the index of the tty
310 *
311 * This routine returns a tty driver structure, given a device number
312 * and also passes back the index number.
313 *
314 * Locking: caller must hold tty_mutex
315 */
316
317static struct tty_driver *get_tty_driver(dev_t device, int *index)
318{
319 struct tty_driver *p;
320
321 list_for_each_entry(p, &tty_drivers, tty_drivers) {
322 dev_t base = MKDEV(p->major, p->minor_start);
323 if (device < base || device >= base + p->num)
324 continue;
325 *index = device - base;
326 return tty_driver_kref_get(p);
327 }
328 return NULL;
329}
330
331/**
332 * tty_dev_name_to_number - return dev_t for device name
333 * @name: user space name of device under /dev
334 * @number: pointer to dev_t that this function will populate
335 *
336 * This function converts device names like ttyS0 or ttyUSB1 into dev_t
337 * like (4, 64) or (188, 1). If no corresponding driver is registered then
338 * the function returns -ENODEV.
339 *
340 * Locking: this acquires tty_mutex to protect the tty_drivers list from
341 * being modified while we are traversing it, and makes sure to
342 * release it before exiting.
343 */
344int tty_dev_name_to_number(const char *name, dev_t *number)
345{
346 struct tty_driver *p;
347 int ret;
348 int index, prefix_length = 0;
349 const char *str;
350
351 for (str = name; *str && !isdigit(*str); str++)
352 ;
353
354 if (!*str)
355 return -EINVAL;
356
357 ret = kstrtoint(str, 10, &index);
358 if (ret)
359 return ret;
360
361 prefix_length = str - name;
362 mutex_lock(&tty_mutex);
363
364 list_for_each_entry(p, &tty_drivers, tty_drivers)
365 if (prefix_length == strlen(p->name) && strncmp(name,
366 p->name, prefix_length) == 0) {
367 if (index < p->num) {
368 *number = MKDEV(p->major, p->minor_start + index);
369 goto out;
370 }
371 }
372
373 /* if here then driver wasn't found */
374 ret = -ENODEV;
375out:
376 mutex_unlock(&tty_mutex);
377 return ret;
378}
379EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
380
381#ifdef CONFIG_CONSOLE_POLL
382
383/**
384 * tty_find_polling_driver - find device of a polled tty
385 * @name: name string to match
386 * @line: pointer to resulting tty line nr
387 *
388 * This routine returns a tty driver structure, given a name
389 * and the condition that the tty driver is capable of polled
390 * operation.
391 */
392struct tty_driver *tty_find_polling_driver(char *name, int *line)
393{
394 struct tty_driver *p, *res = NULL;
395 int tty_line = 0;
396 int len;
397 char *str, *stp;
398
399 for (str = name; *str; str++)
400 if ((*str >= '0' && *str <= '9') || *str == ',')
401 break;
402 if (!*str)
403 return NULL;
404
405 len = str - name;
406 tty_line = simple_strtoul(str, &str, 10);
407
408 mutex_lock(&tty_mutex);
409 /* Search through the tty devices to look for a match */
410 list_for_each_entry(p, &tty_drivers, tty_drivers) {
411 if (strncmp(name, p->name, len) != 0)
412 continue;
413 stp = str;
414 if (*stp == ',')
415 stp++;
416 if (*stp == '\0')
417 stp = NULL;
418
419 if (tty_line >= 0 && tty_line < p->num && p->ops &&
420 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
421 res = tty_driver_kref_get(p);
422 *line = tty_line;
423 break;
424 }
425 }
426 mutex_unlock(&tty_mutex);
427
428 return res;
429}
430EXPORT_SYMBOL_GPL(tty_find_polling_driver);
431#endif
432
433static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
434 size_t count, loff_t *ppos)
435{
436 return 0;
437}
438
439static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
440 size_t count, loff_t *ppos)
441{
442 return -EIO;
443}
444
445/* No kernel lock held - none needed ;) */
446static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
447{
448 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
449}
450
451static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
452 unsigned long arg)
453{
454 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
455}
456
457static long hung_up_tty_compat_ioctl(struct file *file,
458 unsigned int cmd, unsigned long arg)
459{
460 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
461}
462
463static int hung_up_tty_fasync(int fd, struct file *file, int on)
464{
465 return -ENOTTY;
466}
467
468static void tty_show_fdinfo(struct seq_file *m, struct file *file)
469{
470 struct tty_struct *tty = file_tty(file);
471
472 if (tty && tty->ops && tty->ops->show_fdinfo)
473 tty->ops->show_fdinfo(tty, m);
474}
475
476static const struct file_operations tty_fops = {
477 .llseek = no_llseek,
478 .read = tty_read,
479 .write = tty_write,
480 .poll = tty_poll,
481 .unlocked_ioctl = tty_ioctl,
482 .compat_ioctl = tty_compat_ioctl,
483 .open = tty_open,
484 .release = tty_release,
485 .fasync = tty_fasync,
486 .show_fdinfo = tty_show_fdinfo,
487};
488
489static const struct file_operations console_fops = {
490 .llseek = no_llseek,
491 .read = tty_read,
492 .write = redirected_tty_write,
493 .poll = tty_poll,
494 .unlocked_ioctl = tty_ioctl,
495 .compat_ioctl = tty_compat_ioctl,
496 .open = tty_open,
497 .release = tty_release,
498 .fasync = tty_fasync,
499};
500
501static const struct file_operations hung_up_tty_fops = {
502 .llseek = no_llseek,
503 .read = hung_up_tty_read,
504 .write = hung_up_tty_write,
505 .poll = hung_up_tty_poll,
506 .unlocked_ioctl = hung_up_tty_ioctl,
507 .compat_ioctl = hung_up_tty_compat_ioctl,
508 .release = tty_release,
509 .fasync = hung_up_tty_fasync,
510};
511
512static DEFINE_SPINLOCK(redirect_lock);
513static struct file *redirect;
514
515/**
516 * tty_wakeup - request more data
517 * @tty: terminal
518 *
519 * Internal and external helper for wakeups of tty. This function
520 * informs the line discipline if present that the driver is ready
521 * to receive more output data.
522 */
523
524void tty_wakeup(struct tty_struct *tty)
525{
526 struct tty_ldisc *ld;
527
528 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
529 ld = tty_ldisc_ref(tty);
530 if (ld) {
531 if (ld->ops->write_wakeup)
532 ld->ops->write_wakeup(tty);
533 tty_ldisc_deref(ld);
534 }
535 }
536 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
537}
538
539EXPORT_SYMBOL_GPL(tty_wakeup);
540
541/**
542 * __tty_hangup - actual handler for hangup events
543 * @work: tty device
544 *
545 * This can be called by a "kworker" kernel thread. That is process
546 * synchronous but doesn't hold any locks, so we need to make sure we
547 * have the appropriate locks for what we're doing.
548 *
549 * The hangup event clears any pending redirections onto the hung up
550 * device. It ensures future writes will error and it does the needed
551 * line discipline hangup and signal delivery. The tty object itself
552 * remains intact.
553 *
554 * Locking:
555 * BTM
556 * redirect lock for undoing redirection
557 * file list lock for manipulating list of ttys
558 * tty_ldiscs_lock from called functions
559 * termios_rwsem resetting termios data
560 * tasklist_lock to walk task list for hangup event
561 * ->siglock to protect ->signal/->sighand
562 */
563static void __tty_hangup(struct tty_struct *tty, int exit_session)
564{
565 struct file *cons_filp = NULL;
566 struct file *filp, *f = NULL;
567 struct tty_file_private *priv;
568 int closecount = 0, n;
569 int refs;
570
571 if (!tty)
572 return;
573
574
575 spin_lock(&redirect_lock);
576 if (redirect && file_tty(redirect) == tty) {
577 f = redirect;
578 redirect = NULL;
579 }
580 spin_unlock(&redirect_lock);
581
582 tty_lock(tty);
583
584 if (test_bit(TTY_HUPPED, &tty->flags)) {
585 tty_unlock(tty);
586 return;
587 }
588
589 /*
590 * Some console devices aren't actually hung up for technical and
591 * historical reasons, which can lead to indefinite interruptible
592 * sleep in n_tty_read(). The following explicitly tells
593 * n_tty_read() to abort readers.
594 */
595 set_bit(TTY_HUPPING, &tty->flags);
596
597 /* inuse_filps is protected by the single tty lock,
598 this really needs to change if we want to flush the
599 workqueue with the lock held */
600 check_tty_count(tty, "tty_hangup");
601
602 spin_lock(&tty->files_lock);
603 /* This breaks for file handles being sent over AF_UNIX sockets ? */
604 list_for_each_entry(priv, &tty->tty_files, list) {
605 filp = priv->file;
606 if (filp->f_op->write == redirected_tty_write)
607 cons_filp = filp;
608 if (filp->f_op->write != tty_write)
609 continue;
610 closecount++;
611 __tty_fasync(-1, filp, 0); /* can't block */
612 filp->f_op = &hung_up_tty_fops;
613 }
614 spin_unlock(&tty->files_lock);
615
616 refs = tty_signal_session_leader(tty, exit_session);
617 /* Account for the p->signal references we killed */
618 while (refs--)
619 tty_kref_put(tty);
620
621 tty_ldisc_hangup(tty, cons_filp != NULL);
622
623 spin_lock_irq(&tty->ctrl_lock);
624 clear_bit(TTY_THROTTLED, &tty->flags);
625 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
626 put_pid(tty->session);
627 put_pid(tty->pgrp);
628 tty->session = NULL;
629 tty->pgrp = NULL;
630 tty->ctrl_status = 0;
631 spin_unlock_irq(&tty->ctrl_lock);
632
633 /*
634 * If one of the devices matches a console pointer, we
635 * cannot just call hangup() because that will cause
636 * tty->count and state->count to go out of sync.
637 * So we just call close() the right number of times.
638 */
639 if (cons_filp) {
640 if (tty->ops->close)
641 for (n = 0; n < closecount; n++)
642 tty->ops->close(tty, cons_filp);
643 } else if (tty->ops->hangup)
644 tty->ops->hangup(tty);
645 /*
646 * We don't want to have driver/ldisc interactions beyond the ones
647 * we did here. The driver layer expects no calls after ->hangup()
648 * from the ldisc side, which is now guaranteed.
649 */
650 set_bit(TTY_HUPPED, &tty->flags);
651 clear_bit(TTY_HUPPING, &tty->flags);
652 tty_unlock(tty);
653
654 if (f)
655 fput(f);
656}
657
658static void do_tty_hangup(struct work_struct *work)
659{
660 struct tty_struct *tty =
661 container_of(work, struct tty_struct, hangup_work);
662
663 __tty_hangup(tty, 0);
664}
665
666/**
667 * tty_hangup - trigger a hangup event
668 * @tty: tty to hangup
669 *
670 * A carrier loss (virtual or otherwise) has occurred on this like
671 * schedule a hangup sequence to run after this event.
672 */
673
674void tty_hangup(struct tty_struct *tty)
675{
676 tty_debug_hangup(tty, "hangup\n");
677 schedule_work(&tty->hangup_work);
678}
679
680EXPORT_SYMBOL(tty_hangup);
681
682/**
683 * tty_vhangup - process vhangup
684 * @tty: tty to hangup
685 *
686 * The user has asked via system call for the terminal to be hung up.
687 * We do this synchronously so that when the syscall returns the process
688 * is complete. That guarantee is necessary for security reasons.
689 */
690
691void tty_vhangup(struct tty_struct *tty)
692{
693 tty_debug_hangup(tty, "vhangup\n");
694 __tty_hangup(tty, 0);
695}
696
697EXPORT_SYMBOL(tty_vhangup);
698
699
700/**
701 * tty_vhangup_self - process vhangup for own ctty
702 *
703 * Perform a vhangup on the current controlling tty
704 */
705
706void tty_vhangup_self(void)
707{
708 struct tty_struct *tty;
709
710 tty = get_current_tty();
711 if (tty) {
712 tty_vhangup(tty);
713 tty_kref_put(tty);
714 }
715}
716
717/**
718 * tty_vhangup_session - hangup session leader exit
719 * @tty: tty to hangup
720 *
721 * The session leader is exiting and hanging up its controlling terminal.
722 * Every process in the foreground process group is signalled SIGHUP.
723 *
724 * We do this synchronously so that when the syscall returns the process
725 * is complete. That guarantee is necessary for security reasons.
726 */
727
728void tty_vhangup_session(struct tty_struct *tty)
729{
730 tty_debug_hangup(tty, "session hangup\n");
731 __tty_hangup(tty, 1);
732}
733
734/**
735 * tty_hung_up_p - was tty hung up
736 * @filp: file pointer of tty
737 *
738 * Return true if the tty has been subject to a vhangup or a carrier
739 * loss
740 */
741
742int tty_hung_up_p(struct file *filp)
743{
744 return (filp && filp->f_op == &hung_up_tty_fops);
745}
746
747EXPORT_SYMBOL(tty_hung_up_p);
748
749/**
750 * stop_tty - propagate flow control
751 * @tty: tty to stop
752 *
753 * Perform flow control to the driver. May be called
754 * on an already stopped device and will not re-call the driver
755 * method.
756 *
757 * This functionality is used by both the line disciplines for
758 * halting incoming flow and by the driver. It may therefore be
759 * called from any context, may be under the tty atomic_write_lock
760 * but not always.
761 *
762 * Locking:
763 * flow_lock
764 */
765
766void __stop_tty(struct tty_struct *tty)
767{
768 if (tty->stopped)
769 return;
770 tty->stopped = 1;
771 if (tty->ops->stop)
772 tty->ops->stop(tty);
773}
774
775void stop_tty(struct tty_struct *tty)
776{
777 unsigned long flags;
778
779 spin_lock_irqsave(&tty->flow_lock, flags);
780 __stop_tty(tty);
781 spin_unlock_irqrestore(&tty->flow_lock, flags);
782}
783EXPORT_SYMBOL(stop_tty);
784
785/**
786 * start_tty - propagate flow control
787 * @tty: tty to start
788 *
789 * Start a tty that has been stopped if at all possible. If this
790 * tty was previous stopped and is now being started, the driver
791 * start method is invoked and the line discipline woken.
792 *
793 * Locking:
794 * flow_lock
795 */
796
797void __start_tty(struct tty_struct *tty)
798{
799 if (!tty->stopped || tty->flow_stopped)
800 return;
801 tty->stopped = 0;
802 if (tty->ops->start)
803 tty->ops->start(tty);
804 tty_wakeup(tty);
805}
806
807void start_tty(struct tty_struct *tty)
808{
809 unsigned long flags;
810
811 spin_lock_irqsave(&tty->flow_lock, flags);
812 __start_tty(tty);
813 spin_unlock_irqrestore(&tty->flow_lock, flags);
814}
815EXPORT_SYMBOL(start_tty);
816
817static void tty_update_time(struct timespec *time)
818{
819 unsigned long sec = get_seconds();
820
821 /*
822 * We only care if the two values differ in anything other than the
823 * lower three bits (i.e every 8 seconds). If so, then we can update
824 * the time of the tty device, otherwise it could be construded as a
825 * security leak to let userspace know the exact timing of the tty.
826 */
827 if ((sec ^ time->tv_sec) & ~7)
828 time->tv_sec = sec;
829}
830
831/**
832 * tty_read - read method for tty device files
833 * @file: pointer to tty file
834 * @buf: user buffer
835 * @count: size of user buffer
836 * @ppos: unused
837 *
838 * Perform the read system call function on this terminal device. Checks
839 * for hung up devices before calling the line discipline method.
840 *
841 * Locking:
842 * Locks the line discipline internally while needed. Multiple
843 * read calls may be outstanding in parallel.
844 */
845
846static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
847 loff_t *ppos)
848{
849 int i;
850 struct inode *inode = file_inode(file);
851 struct tty_struct *tty = file_tty(file);
852 struct tty_ldisc *ld;
853
854 if (tty_paranoia_check(tty, inode, "tty_read"))
855 return -EIO;
856 if (!tty || tty_io_error(tty))
857 return -EIO;
858
859 /* We want to wait for the line discipline to sort out in this
860 situation */
861 ld = tty_ldisc_ref_wait(tty);
862 if (!ld)
863 return hung_up_tty_read(file, buf, count, ppos);
864 if (ld->ops->read)
865 i = ld->ops->read(tty, file, buf, count);
866 else
867 i = -EIO;
868 tty_ldisc_deref(ld);
869
870 if (i > 0)
871 tty_update_time(&inode->i_atime);
872
873 return i;
874}
875
876static void tty_write_unlock(struct tty_struct *tty)
877{
878 mutex_unlock(&tty->atomic_write_lock);
879 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
880}
881
882static int tty_write_lock(struct tty_struct *tty, int ndelay)
883{
884 if (!mutex_trylock(&tty->atomic_write_lock)) {
885 if (ndelay)
886 return -EAGAIN;
887 if (mutex_lock_interruptible(&tty->atomic_write_lock))
888 return -ERESTARTSYS;
889 }
890 return 0;
891}
892
893/*
894 * Split writes up in sane blocksizes to avoid
895 * denial-of-service type attacks
896 */
897static inline ssize_t do_tty_write(
898 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
899 struct tty_struct *tty,
900 struct file *file,
901 const char __user *buf,
902 size_t count)
903{
904 ssize_t ret, written = 0;
905 unsigned int chunk;
906
907 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
908 if (ret < 0)
909 return ret;
910
911 /*
912 * We chunk up writes into a temporary buffer. This
913 * simplifies low-level drivers immensely, since they
914 * don't have locking issues and user mode accesses.
915 *
916 * But if TTY_NO_WRITE_SPLIT is set, we should use a
917 * big chunk-size..
918 *
919 * The default chunk-size is 2kB, because the NTTY
920 * layer has problems with bigger chunks. It will
921 * claim to be able to handle more characters than
922 * it actually does.
923 *
924 * FIXME: This can probably go away now except that 64K chunks
925 * are too likely to fail unless switched to vmalloc...
926 */
927 chunk = 2048;
928 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
929 chunk = 65536;
930 if (count < chunk)
931 chunk = count;
932
933 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
934 if (tty->write_cnt < chunk) {
935 unsigned char *buf_chunk;
936
937 if (chunk < 1024)
938 chunk = 1024;
939
940 buf_chunk = kmalloc(chunk, GFP_KERNEL);
941 if (!buf_chunk) {
942 ret = -ENOMEM;
943 goto out;
944 }
945 kfree(tty->write_buf);
946 tty->write_cnt = chunk;
947 tty->write_buf = buf_chunk;
948 }
949
950 /* Do the write .. */
951 for (;;) {
952 size_t size = count;
953 if (size > chunk)
954 size = chunk;
955 ret = -EFAULT;
956 if (copy_from_user(tty->write_buf, buf, size))
957 break;
958 ret = write(tty, file, tty->write_buf, size);
959 if (ret <= 0)
960 break;
961 written += ret;
962 buf += ret;
963 count -= ret;
964 if (!count)
965 break;
966 ret = -ERESTARTSYS;
967 if (signal_pending(current))
968 break;
969 cond_resched();
970 }
971 if (written) {
972 tty_update_time(&file_inode(file)->i_mtime);
973 ret = written;
974 }
975out:
976 tty_write_unlock(tty);
977 return ret;
978}
979
980/**
981 * tty_write_message - write a message to a certain tty, not just the console.
982 * @tty: the destination tty_struct
983 * @msg: the message to write
984 *
985 * This is used for messages that need to be redirected to a specific tty.
986 * We don't put it into the syslog queue right now maybe in the future if
987 * really needed.
988 *
989 * We must still hold the BTM and test the CLOSING flag for the moment.
990 */
991
992void tty_write_message(struct tty_struct *tty, char *msg)
993{
994 if (tty) {
995 mutex_lock(&tty->atomic_write_lock);
996 tty_lock(tty);
997 if (tty->ops->write && tty->count > 0)
998 tty->ops->write(tty, msg, strlen(msg));
999 tty_unlock(tty);
1000 tty_write_unlock(tty);
1001 }
1002 return;
1003}
1004
1005
1006/**
1007 * tty_write - write method for tty device file
1008 * @file: tty file pointer
1009 * @buf: user data to write
1010 * @count: bytes to write
1011 * @ppos: unused
1012 *
1013 * Write data to a tty device via the line discipline.
1014 *
1015 * Locking:
1016 * Locks the line discipline as required
1017 * Writes to the tty driver are serialized by the atomic_write_lock
1018 * and are then processed in chunks to the device. The line discipline
1019 * write method will not be invoked in parallel for each device.
1020 */
1021
1022static ssize_t tty_write(struct file *file, const char __user *buf,
1023 size_t count, loff_t *ppos)
1024{
1025 struct tty_struct *tty = file_tty(file);
1026 struct tty_ldisc *ld;
1027 ssize_t ret;
1028
1029 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1030 return -EIO;
1031 if (!tty || !tty->ops->write || tty_io_error(tty))
1032 return -EIO;
1033 /* Short term debug to catch buggy drivers */
1034 if (tty->ops->write_room == NULL)
1035 tty_err(tty, "missing write_room method\n");
1036 ld = tty_ldisc_ref_wait(tty);
1037 if (!ld)
1038 return hung_up_tty_write(file, buf, count, ppos);
1039 if (!ld->ops->write)
1040 ret = -EIO;
1041 else
1042 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1043 tty_ldisc_deref(ld);
1044 return ret;
1045}
1046
1047ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1048 size_t count, loff_t *ppos)
1049{
1050 struct file *p = NULL;
1051
1052 spin_lock(&redirect_lock);
1053 if (redirect)
1054 p = get_file(redirect);
1055 spin_unlock(&redirect_lock);
1056
1057 if (p) {
1058 ssize_t res;
1059 res = vfs_write(p, buf, count, &p->f_pos);
1060 fput(p);
1061 return res;
1062 }
1063 return tty_write(file, buf, count, ppos);
1064}
1065
1066/**
1067 * tty_send_xchar - send priority character
1068 *
1069 * Send a high priority character to the tty even if stopped
1070 *
1071 * Locking: none for xchar method, write ordering for write method.
1072 */
1073
1074int tty_send_xchar(struct tty_struct *tty, char ch)
1075{
1076 int was_stopped = tty->stopped;
1077
1078 if (tty->ops->send_xchar) {
1079 down_read(&tty->termios_rwsem);
1080 tty->ops->send_xchar(tty, ch);
1081 up_read(&tty->termios_rwsem);
1082 return 0;
1083 }
1084
1085 if (tty_write_lock(tty, 0) < 0)
1086 return -ERESTARTSYS;
1087
1088 down_read(&tty->termios_rwsem);
1089 if (was_stopped)
1090 start_tty(tty);
1091 tty->ops->write(tty, &ch, 1);
1092 if (was_stopped)
1093 stop_tty(tty);
1094 up_read(&tty->termios_rwsem);
1095 tty_write_unlock(tty);
1096 return 0;
1097}
1098
1099static char ptychar[] = "pqrstuvwxyzabcde";
1100
1101/**
1102 * pty_line_name - generate name for a pty
1103 * @driver: the tty driver in use
1104 * @index: the minor number
1105 * @p: output buffer of at least 6 bytes
1106 *
1107 * Generate a name from a driver reference and write it to the output
1108 * buffer.
1109 *
1110 * Locking: None
1111 */
1112static void pty_line_name(struct tty_driver *driver, int index, char *p)
1113{
1114 int i = index + driver->name_base;
1115 /* ->name is initialized to "ttyp", but "tty" is expected */
1116 sprintf(p, "%s%c%x",
1117 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1118 ptychar[i >> 4 & 0xf], i & 0xf);
1119}
1120
1121/**
1122 * tty_line_name - generate name for a tty
1123 * @driver: the tty driver in use
1124 * @index: the minor number
1125 * @p: output buffer of at least 7 bytes
1126 *
1127 * Generate a name from a driver reference and write it to the output
1128 * buffer.
1129 *
1130 * Locking: None
1131 */
1132static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1133{
1134 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1135 return sprintf(p, "%s", driver->name);
1136 else
1137 return sprintf(p, "%s%d", driver->name,
1138 index + driver->name_base);
1139}
1140
1141/**
1142 * tty_driver_lookup_tty() - find an existing tty, if any
1143 * @driver: the driver for the tty
1144 * @idx: the minor number
1145 *
1146 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1147 * driver lookup() method returns an error.
1148 *
1149 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1150 */
1151static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1152 struct file *file, int idx)
1153{
1154 struct tty_struct *tty;
1155
1156 if (driver->ops->lookup)
1157 if (!file)
1158 tty = ERR_PTR(-EIO);
1159 else
1160 tty = driver->ops->lookup(driver, file, idx);
1161 else
1162 tty = driver->ttys[idx];
1163
1164 if (!IS_ERR(tty))
1165 tty_kref_get(tty);
1166 return tty;
1167}
1168
1169/**
1170 * tty_init_termios - helper for termios setup
1171 * @tty: the tty to set up
1172 *
1173 * Initialise the termios structures for this tty. Thus runs under
1174 * the tty_mutex currently so we can be relaxed about ordering.
1175 */
1176
1177void tty_init_termios(struct tty_struct *tty)
1178{
1179 struct ktermios *tp;
1180 int idx = tty->index;
1181
1182 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1183 tty->termios = tty->driver->init_termios;
1184 else {
1185 /* Check for lazy saved data */
1186 tp = tty->driver->termios[idx];
1187 if (tp != NULL) {
1188 tty->termios = *tp;
1189 tty->termios.c_line = tty->driver->init_termios.c_line;
1190 } else
1191 tty->termios = tty->driver->init_termios;
1192 }
1193 /* Compatibility until drivers always set this */
1194 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1195 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1196}
1197EXPORT_SYMBOL_GPL(tty_init_termios);
1198
1199int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1200{
1201 tty_init_termios(tty);
1202 tty_driver_kref_get(driver);
1203 tty->count++;
1204 driver->ttys[tty->index] = tty;
1205 return 0;
1206}
1207EXPORT_SYMBOL_GPL(tty_standard_install);
1208
1209/**
1210 * tty_driver_install_tty() - install a tty entry in the driver
1211 * @driver: the driver for the tty
1212 * @tty: the tty
1213 *
1214 * Install a tty object into the driver tables. The tty->index field
1215 * will be set by the time this is called. This method is responsible
1216 * for ensuring any need additional structures are allocated and
1217 * configured.
1218 *
1219 * Locking: tty_mutex for now
1220 */
1221static int tty_driver_install_tty(struct tty_driver *driver,
1222 struct tty_struct *tty)
1223{
1224 return driver->ops->install ? driver->ops->install(driver, tty) :
1225 tty_standard_install(driver, tty);
1226}
1227
1228/**
1229 * tty_driver_remove_tty() - remove a tty from the driver tables
1230 * @driver: the driver for the tty
1231 * @idx: the minor number
1232 *
1233 * Remvoe a tty object from the driver tables. The tty->index field
1234 * will be set by the time this is called.
1235 *
1236 * Locking: tty_mutex for now
1237 */
1238static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1239{
1240 if (driver->ops->remove)
1241 driver->ops->remove(driver, tty);
1242 else
1243 driver->ttys[tty->index] = NULL;
1244}
1245
1246/*
1247 * tty_reopen() - fast re-open of an open tty
1248 * @tty - the tty to open
1249 *
1250 * Return 0 on success, -errno on error.
1251 * Re-opens on master ptys are not allowed and return -EIO.
1252 *
1253 * Locking: Caller must hold tty_lock
1254 */
1255static int tty_reopen(struct tty_struct *tty)
1256{
1257 struct tty_driver *driver = tty->driver;
1258
1259 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1260 driver->subtype == PTY_TYPE_MASTER)
1261 return -EIO;
1262
1263 if (!tty->count)
1264 return -EAGAIN;
1265
1266 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1267 return -EBUSY;
1268
1269 tty->count++;
1270
1271 if (!tty->ldisc)
1272 return tty_ldisc_reinit(tty, tty->termios.c_line);
1273
1274 return 0;
1275}
1276
1277/**
1278 * tty_init_dev - initialise a tty device
1279 * @driver: tty driver we are opening a device on
1280 * @idx: device index
1281 * @ret_tty: returned tty structure
1282 *
1283 * Prepare a tty device. This may not be a "new" clean device but
1284 * could also be an active device. The pty drivers require special
1285 * handling because of this.
1286 *
1287 * Locking:
1288 * The function is called under the tty_mutex, which
1289 * protects us from the tty struct or driver itself going away.
1290 *
1291 * On exit the tty device has the line discipline attached and
1292 * a reference count of 1. If a pair was created for pty/tty use
1293 * and the other was a pty master then it too has a reference count of 1.
1294 *
1295 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1296 * failed open. The new code protects the open with a mutex, so it's
1297 * really quite straightforward. The mutex locking can probably be
1298 * relaxed for the (most common) case of reopening a tty.
1299 */
1300
1301struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1302{
1303 struct tty_struct *tty;
1304 int retval;
1305
1306 /*
1307 * First time open is complex, especially for PTY devices.
1308 * This code guarantees that either everything succeeds and the
1309 * TTY is ready for operation, or else the table slots are vacated
1310 * and the allocated memory released. (Except that the termios
1311 * may be retained.)
1312 */
1313
1314 if (!try_module_get(driver->owner))
1315 return ERR_PTR(-ENODEV);
1316
1317 tty = alloc_tty_struct(driver, idx);
1318 if (!tty) {
1319 retval = -ENOMEM;
1320 goto err_module_put;
1321 }
1322
1323 tty_lock(tty);
1324 retval = tty_driver_install_tty(driver, tty);
1325 if (retval < 0)
1326 goto err_free_tty;
1327
1328 if (!tty->port)
1329 tty->port = driver->ports[idx];
1330
1331 WARN_RATELIMIT(!tty->port,
1332 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1333 __func__, tty->driver->name);
1334
1335 retval = tty_ldisc_lock(tty, 5 * HZ);
1336 if (retval)
1337 goto err_release_lock;
1338 tty->port->itty = tty;
1339
1340 /*
1341 * Structures all installed ... call the ldisc open routines.
1342 * If we fail here just call release_tty to clean up. No need
1343 * to decrement the use counts, as release_tty doesn't care.
1344 */
1345 retval = tty_ldisc_setup(tty, tty->link);
1346 if (retval)
1347 goto err_release_tty;
1348 tty_ldisc_unlock(tty);
1349 /* Return the tty locked so that it cannot vanish under the caller */
1350 return tty;
1351
1352err_free_tty:
1353 tty_unlock(tty);
1354 free_tty_struct(tty);
1355err_module_put:
1356 module_put(driver->owner);
1357 return ERR_PTR(retval);
1358
1359 /* call the tty release_tty routine to clean out this slot */
1360err_release_tty:
1361 tty_ldisc_unlock(tty);
1362 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1363 retval, idx);
1364err_release_lock:
1365 tty_unlock(tty);
1366 release_tty(tty, idx);
1367 return ERR_PTR(retval);
1368}
1369
1370static void tty_free_termios(struct tty_struct *tty)
1371{
1372 struct ktermios *tp;
1373 int idx = tty->index;
1374
1375 /* If the port is going to reset then it has no termios to save */
1376 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1377 return;
1378
1379 /* Stash the termios data */
1380 tp = tty->driver->termios[idx];
1381 if (tp == NULL) {
1382 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1383 if (tp == NULL)
1384 return;
1385 tty->driver->termios[idx] = tp;
1386 }
1387 *tp = tty->termios;
1388}
1389
1390/**
1391 * tty_flush_works - flush all works of a tty/pty pair
1392 * @tty: tty device to flush works for (or either end of a pty pair)
1393 *
1394 * Sync flush all works belonging to @tty (and the 'other' tty).
1395 */
1396static void tty_flush_works(struct tty_struct *tty)
1397{
1398 flush_work(&tty->SAK_work);
1399 flush_work(&tty->hangup_work);
1400 if (tty->link) {
1401 flush_work(&tty->link->SAK_work);
1402 flush_work(&tty->link->hangup_work);
1403 }
1404}
1405
1406/**
1407 * release_one_tty - release tty structure memory
1408 * @kref: kref of tty we are obliterating
1409 *
1410 * Releases memory associated with a tty structure, and clears out the
1411 * driver table slots. This function is called when a device is no longer
1412 * in use. It also gets called when setup of a device fails.
1413 *
1414 * Locking:
1415 * takes the file list lock internally when working on the list
1416 * of ttys that the driver keeps.
1417 *
1418 * This method gets called from a work queue so that the driver private
1419 * cleanup ops can sleep (needed for USB at least)
1420 */
1421static void release_one_tty(struct work_struct *work)
1422{
1423 struct tty_struct *tty =
1424 container_of(work, struct tty_struct, hangup_work);
1425 struct tty_driver *driver = tty->driver;
1426 struct module *owner = driver->owner;
1427
1428 if (tty->ops->cleanup)
1429 tty->ops->cleanup(tty);
1430
1431 tty->magic = 0;
1432 tty_driver_kref_put(driver);
1433 module_put(owner);
1434
1435 spin_lock(&tty->files_lock);
1436 list_del_init(&tty->tty_files);
1437 spin_unlock(&tty->files_lock);
1438
1439 put_pid(tty->pgrp);
1440 put_pid(tty->session);
1441 free_tty_struct(tty);
1442}
1443
1444static void queue_release_one_tty(struct kref *kref)
1445{
1446 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1447
1448 /* The hangup queue is now free so we can reuse it rather than
1449 waste a chunk of memory for each port */
1450 INIT_WORK(&tty->hangup_work, release_one_tty);
1451 schedule_work(&tty->hangup_work);
1452}
1453
1454/**
1455 * tty_kref_put - release a tty kref
1456 * @tty: tty device
1457 *
1458 * Release a reference to a tty device and if need be let the kref
1459 * layer destruct the object for us
1460 */
1461
1462void tty_kref_put(struct tty_struct *tty)
1463{
1464 if (tty)
1465 kref_put(&tty->kref, queue_release_one_tty);
1466}
1467EXPORT_SYMBOL(tty_kref_put);
1468
1469/**
1470 * release_tty - release tty structure memory
1471 *
1472 * Release both @tty and a possible linked partner (think pty pair),
1473 * and decrement the refcount of the backing module.
1474 *
1475 * Locking:
1476 * tty_mutex
1477 * takes the file list lock internally when working on the list
1478 * of ttys that the driver keeps.
1479 *
1480 */
1481static void release_tty(struct tty_struct *tty, int idx)
1482{
1483 /* This should always be true but check for the moment */
1484 WARN_ON(tty->index != idx);
1485 WARN_ON(!mutex_is_locked(&tty_mutex));
1486 if (tty->ops->shutdown)
1487 tty->ops->shutdown(tty);
1488 tty_free_termios(tty);
1489 tty_driver_remove_tty(tty->driver, tty);
1490 tty->port->itty = NULL;
1491 if (tty->link)
1492 tty->link->port->itty = NULL;
1493 tty_buffer_cancel_work(tty->port);
1494 if (tty->link)
1495 tty_buffer_cancel_work(tty->link->port);
1496
1497 tty_kref_put(tty->link);
1498 tty_kref_put(tty);
1499}
1500
1501/**
1502 * tty_release_checks - check a tty before real release
1503 * @tty: tty to check
1504 * @o_tty: link of @tty (if any)
1505 * @idx: index of the tty
1506 *
1507 * Performs some paranoid checking before true release of the @tty.
1508 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1509 */
1510static int tty_release_checks(struct tty_struct *tty, int idx)
1511{
1512#ifdef TTY_PARANOIA_CHECK
1513 if (idx < 0 || idx >= tty->driver->num) {
1514 tty_debug(tty, "bad idx %d\n", idx);
1515 return -1;
1516 }
1517
1518 /* not much to check for devpts */
1519 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1520 return 0;
1521
1522 if (tty != tty->driver->ttys[idx]) {
1523 tty_debug(tty, "bad driver table[%d] = %p\n",
1524 idx, tty->driver->ttys[idx]);
1525 return -1;
1526 }
1527 if (tty->driver->other) {
1528 struct tty_struct *o_tty = tty->link;
1529
1530 if (o_tty != tty->driver->other->ttys[idx]) {
1531 tty_debug(tty, "bad other table[%d] = %p\n",
1532 idx, tty->driver->other->ttys[idx]);
1533 return -1;
1534 }
1535 if (o_tty->link != tty) {
1536 tty_debug(tty, "bad link = %p\n", o_tty->link);
1537 return -1;
1538 }
1539 }
1540#endif
1541 return 0;
1542}
1543
1544/**
1545 * tty_kclose - closes tty opened by tty_kopen
1546 * @tty: tty device
1547 *
1548 * Performs the final steps to release and free a tty device. It is the
1549 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1550 * flag on tty->port.
1551 */
1552void tty_kclose(struct tty_struct *tty)
1553{
1554 /*
1555 * Ask the line discipline code to release its structures
1556 */
1557 tty_ldisc_release(tty);
1558
1559 /* Wait for pending work before tty destruction commmences */
1560 tty_flush_works(tty);
1561
1562 tty_debug_hangup(tty, "freeing structure\n");
1563 /*
1564 * The release_tty function takes care of the details of clearing
1565 * the slots and preserving the termios structure. The tty_unlock_pair
1566 * should be safe as we keep a kref while the tty is locked (so the
1567 * unlock never unlocks a freed tty).
1568 */
1569 mutex_lock(&tty_mutex);
1570 tty_port_set_kopened(tty->port, 0);
1571 release_tty(tty, tty->index);
1572 mutex_unlock(&tty_mutex);
1573}
1574EXPORT_SYMBOL_GPL(tty_kclose);
1575
1576/**
1577 * tty_release_struct - release a tty struct
1578 * @tty: tty device
1579 * @idx: index of the tty
1580 *
1581 * Performs the final steps to release and free a tty device. It is
1582 * roughly the reverse of tty_init_dev.
1583 */
1584void tty_release_struct(struct tty_struct *tty, int idx)
1585{
1586 /*
1587 * Ask the line discipline code to release its structures
1588 */
1589 tty_ldisc_release(tty);
1590
1591 /* Wait for pending work before tty destruction commmences */
1592 tty_flush_works(tty);
1593
1594 tty_debug_hangup(tty, "freeing structure\n");
1595 /*
1596 * The release_tty function takes care of the details of clearing
1597 * the slots and preserving the termios structure. The tty_unlock_pair
1598 * should be safe as we keep a kref while the tty is locked (so the
1599 * unlock never unlocks a freed tty).
1600 */
1601 mutex_lock(&tty_mutex);
1602 release_tty(tty, idx);
1603 mutex_unlock(&tty_mutex);
1604}
1605EXPORT_SYMBOL_GPL(tty_release_struct);
1606
1607/**
1608 * tty_release - vfs callback for close
1609 * @inode: inode of tty
1610 * @filp: file pointer for handle to tty
1611 *
1612 * Called the last time each file handle is closed that references
1613 * this tty. There may however be several such references.
1614 *
1615 * Locking:
1616 * Takes bkl. See tty_release_dev
1617 *
1618 * Even releasing the tty structures is a tricky business.. We have
1619 * to be very careful that the structures are all released at the
1620 * same time, as interrupts might otherwise get the wrong pointers.
1621 *
1622 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1623 * lead to double frees or releasing memory still in use.
1624 */
1625
1626int tty_release(struct inode *inode, struct file *filp)
1627{
1628 struct tty_struct *tty = file_tty(filp);
1629 struct tty_struct *o_tty = NULL;
1630 int do_sleep, final;
1631 int idx;
1632 long timeout = 0;
1633 int once = 1;
1634
1635 if (tty_paranoia_check(tty, inode, __func__))
1636 return 0;
1637
1638 tty_lock(tty);
1639 check_tty_count(tty, __func__);
1640
1641 __tty_fasync(-1, filp, 0);
1642
1643 idx = tty->index;
1644 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1645 tty->driver->subtype == PTY_TYPE_MASTER)
1646 o_tty = tty->link;
1647
1648 if (tty_release_checks(tty, idx)) {
1649 tty_unlock(tty);
1650 return 0;
1651 }
1652
1653 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1654
1655 if (tty->ops->close)
1656 tty->ops->close(tty, filp);
1657
1658 /* If tty is pty master, lock the slave pty (stable lock order) */
1659 tty_lock_slave(o_tty);
1660
1661 /*
1662 * Sanity check: if tty->count is going to zero, there shouldn't be
1663 * any waiters on tty->read_wait or tty->write_wait. We test the
1664 * wait queues and kick everyone out _before_ actually starting to
1665 * close. This ensures that we won't block while releasing the tty
1666 * structure.
1667 *
1668 * The test for the o_tty closing is necessary, since the master and
1669 * slave sides may close in any order. If the slave side closes out
1670 * first, its count will be one, since the master side holds an open.
1671 * Thus this test wouldn't be triggered at the time the slave closed,
1672 * so we do it now.
1673 */
1674 while (1) {
1675 do_sleep = 0;
1676
1677 if (tty->count <= 1) {
1678 if (waitqueue_active(&tty->read_wait)) {
1679 wake_up_poll(&tty->read_wait, EPOLLIN);
1680 do_sleep++;
1681 }
1682 if (waitqueue_active(&tty->write_wait)) {
1683 wake_up_poll(&tty->write_wait, EPOLLOUT);
1684 do_sleep++;
1685 }
1686 }
1687 if (o_tty && o_tty->count <= 1) {
1688 if (waitqueue_active(&o_tty->read_wait)) {
1689 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1690 do_sleep++;
1691 }
1692 if (waitqueue_active(&o_tty->write_wait)) {
1693 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1694 do_sleep++;
1695 }
1696 }
1697 if (!do_sleep)
1698 break;
1699
1700 if (once) {
1701 once = 0;
1702 tty_warn(tty, "read/write wait queue active!\n");
1703 }
1704 schedule_timeout_killable(timeout);
1705 if (timeout < 120 * HZ)
1706 timeout = 2 * timeout + 1;
1707 else
1708 timeout = MAX_SCHEDULE_TIMEOUT;
1709 }
1710
1711 if (o_tty) {
1712 if (--o_tty->count < 0) {
1713 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1714 o_tty->count = 0;
1715 }
1716 }
1717 if (--tty->count < 0) {
1718 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1719 tty->count = 0;
1720 }
1721
1722 /*
1723 * We've decremented tty->count, so we need to remove this file
1724 * descriptor off the tty->tty_files list; this serves two
1725 * purposes:
1726 * - check_tty_count sees the correct number of file descriptors
1727 * associated with this tty.
1728 * - do_tty_hangup no longer sees this file descriptor as
1729 * something that needs to be handled for hangups.
1730 */
1731 tty_del_file(filp);
1732
1733 /*
1734 * Perform some housekeeping before deciding whether to return.
1735 *
1736 * If _either_ side is closing, make sure there aren't any
1737 * processes that still think tty or o_tty is their controlling
1738 * tty.
1739 */
1740 if (!tty->count) {
1741 read_lock(&tasklist_lock);
1742 session_clear_tty(tty->session);
1743 if (o_tty)
1744 session_clear_tty(o_tty->session);
1745 read_unlock(&tasklist_lock);
1746 }
1747
1748 /* check whether both sides are closing ... */
1749 final = !tty->count && !(o_tty && o_tty->count);
1750
1751 tty_unlock_slave(o_tty);
1752 tty_unlock(tty);
1753
1754 /* At this point, the tty->count == 0 should ensure a dead tty
1755 cannot be re-opened by a racing opener */
1756
1757 if (!final)
1758 return 0;
1759
1760 tty_debug_hangup(tty, "final close\n");
1761
1762 tty_release_struct(tty, idx);
1763 return 0;
1764}
1765
1766/**
1767 * tty_open_current_tty - get locked tty of current task
1768 * @device: device number
1769 * @filp: file pointer to tty
1770 * @return: locked tty of the current task iff @device is /dev/tty
1771 *
1772 * Performs a re-open of the current task's controlling tty.
1773 *
1774 * We cannot return driver and index like for the other nodes because
1775 * devpts will not work then. It expects inodes to be from devpts FS.
1776 */
1777static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1778{
1779 struct tty_struct *tty;
1780 int retval;
1781
1782 if (device != MKDEV(TTYAUX_MAJOR, 0))
1783 return NULL;
1784
1785 tty = get_current_tty();
1786 if (!tty)
1787 return ERR_PTR(-ENXIO);
1788
1789 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1790 /* noctty = 1; */
1791 tty_lock(tty);
1792 tty_kref_put(tty); /* safe to drop the kref now */
1793
1794 retval = tty_reopen(tty);
1795 if (retval < 0) {
1796 tty_unlock(tty);
1797 tty = ERR_PTR(retval);
1798 }
1799 return tty;
1800}
1801
1802/**
1803 * tty_lookup_driver - lookup a tty driver for a given device file
1804 * @device: device number
1805 * @filp: file pointer to tty
1806 * @index: index for the device in the @return driver
1807 * @return: driver for this inode (with increased refcount)
1808 *
1809 * If @return is not erroneous, the caller is responsible to decrement the
1810 * refcount by tty_driver_kref_put.
1811 *
1812 * Locking: tty_mutex protects get_tty_driver
1813 */
1814static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1815 int *index)
1816{
1817 struct tty_driver *driver;
1818
1819 switch (device) {
1820#ifdef CONFIG_VT
1821 case MKDEV(TTY_MAJOR, 0): {
1822 extern struct tty_driver *console_driver;
1823 driver = tty_driver_kref_get(console_driver);
1824 *index = fg_console;
1825 break;
1826 }
1827#endif
1828 case MKDEV(TTYAUX_MAJOR, 1): {
1829 struct tty_driver *console_driver = console_device(index);
1830 if (console_driver) {
1831 driver = tty_driver_kref_get(console_driver);
1832 if (driver && filp) {
1833 /* Don't let /dev/console block */
1834 filp->f_flags |= O_NONBLOCK;
1835 break;
1836 }
1837 }
1838 return ERR_PTR(-ENODEV);
1839 }
1840 default:
1841 driver = get_tty_driver(device, index);
1842 if (!driver)
1843 return ERR_PTR(-ENODEV);
1844 break;
1845 }
1846 return driver;
1847}
1848
1849/**
1850 * tty_kopen - open a tty device for kernel
1851 * @device: dev_t of device to open
1852 *
1853 * Opens tty exclusively for kernel. Performs the driver lookup,
1854 * makes sure it's not already opened and performs the first-time
1855 * tty initialization.
1856 *
1857 * Returns the locked initialized &tty_struct
1858 *
1859 * Claims the global tty_mutex to serialize:
1860 * - concurrent first-time tty initialization
1861 * - concurrent tty driver removal w/ lookup
1862 * - concurrent tty removal from driver table
1863 */
1864struct tty_struct *tty_kopen(dev_t device)
1865{
1866 struct tty_struct *tty;
1867 struct tty_driver *driver = NULL;
1868 int index = -1;
1869
1870 mutex_lock(&tty_mutex);
1871 driver = tty_lookup_driver(device, NULL, &index);
1872 if (IS_ERR(driver)) {
1873 mutex_unlock(&tty_mutex);
1874 return ERR_CAST(driver);
1875 }
1876
1877 /* check whether we're reopening an existing tty */
1878 tty = tty_driver_lookup_tty(driver, NULL, index);
1879 if (IS_ERR(tty))
1880 goto out;
1881
1882 if (tty) {
1883 /* drop kref from tty_driver_lookup_tty() */
1884 tty_kref_put(tty);
1885 tty = ERR_PTR(-EBUSY);
1886 } else { /* tty_init_dev returns tty with the tty_lock held */
1887 tty = tty_init_dev(driver, index);
1888 if (IS_ERR(tty))
1889 goto out;
1890 tty_port_set_kopened(tty->port, 1);
1891 }
1892out:
1893 mutex_unlock(&tty_mutex);
1894 tty_driver_kref_put(driver);
1895 return tty;
1896}
1897EXPORT_SYMBOL_GPL(tty_kopen);
1898
1899/**
1900 * tty_open_by_driver - open a tty device
1901 * @device: dev_t of device to open
1902 * @inode: inode of device file
1903 * @filp: file pointer to tty
1904 *
1905 * Performs the driver lookup, checks for a reopen, or otherwise
1906 * performs the first-time tty initialization.
1907 *
1908 * Returns the locked initialized or re-opened &tty_struct
1909 *
1910 * Claims the global tty_mutex to serialize:
1911 * - concurrent first-time tty initialization
1912 * - concurrent tty driver removal w/ lookup
1913 * - concurrent tty removal from driver table
1914 */
1915static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
1916 struct file *filp)
1917{
1918 struct tty_struct *tty;
1919 struct tty_driver *driver = NULL;
1920 int index = -1;
1921 int retval;
1922
1923 mutex_lock(&tty_mutex);
1924 driver = tty_lookup_driver(device, filp, &index);
1925 if (IS_ERR(driver)) {
1926 mutex_unlock(&tty_mutex);
1927 return ERR_CAST(driver);
1928 }
1929
1930 /* check whether we're reopening an existing tty */
1931 tty = tty_driver_lookup_tty(driver, filp, index);
1932 if (IS_ERR(tty)) {
1933 mutex_unlock(&tty_mutex);
1934 goto out;
1935 }
1936
1937 if (tty) {
1938 if (tty_port_kopened(tty->port)) {
1939 tty_kref_put(tty);
1940 mutex_unlock(&tty_mutex);
1941 tty = ERR_PTR(-EBUSY);
1942 goto out;
1943 }
1944 mutex_unlock(&tty_mutex);
1945 retval = tty_lock_interruptible(tty);
1946 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
1947 if (retval) {
1948 if (retval == -EINTR)
1949 retval = -ERESTARTSYS;
1950 tty = ERR_PTR(retval);
1951 goto out;
1952 }
1953 retval = tty_reopen(tty);
1954 if (retval < 0) {
1955 tty_unlock(tty);
1956 tty = ERR_PTR(retval);
1957 }
1958 } else { /* Returns with the tty_lock held for now */
1959 tty = tty_init_dev(driver, index);
1960 mutex_unlock(&tty_mutex);
1961 }
1962out:
1963 tty_driver_kref_put(driver);
1964 return tty;
1965}
1966
1967/**
1968 * tty_open - open a tty device
1969 * @inode: inode of device file
1970 * @filp: file pointer to tty
1971 *
1972 * tty_open and tty_release keep up the tty count that contains the
1973 * number of opens done on a tty. We cannot use the inode-count, as
1974 * different inodes might point to the same tty.
1975 *
1976 * Open-counting is needed for pty masters, as well as for keeping
1977 * track of serial lines: DTR is dropped when the last close happens.
1978 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1979 *
1980 * The termios state of a pty is reset on first open so that
1981 * settings don't persist across reuse.
1982 *
1983 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1984 * tty->count should protect the rest.
1985 * ->siglock protects ->signal/->sighand
1986 *
1987 * Note: the tty_unlock/lock cases without a ref are only safe due to
1988 * tty_mutex
1989 */
1990
1991static int tty_open(struct inode *inode, struct file *filp)
1992{
1993 struct tty_struct *tty;
1994 int noctty, retval;
1995 dev_t device = inode->i_rdev;
1996 unsigned saved_flags = filp->f_flags;
1997
1998 nonseekable_open(inode, filp);
1999
2000retry_open:
2001 retval = tty_alloc_file(filp);
2002 if (retval)
2003 return -ENOMEM;
2004
2005 tty = tty_open_current_tty(device, filp);
2006 if (!tty)
2007 tty = tty_open_by_driver(device, inode, filp);
2008
2009 if (IS_ERR(tty)) {
2010 tty_free_file(filp);
2011 retval = PTR_ERR(tty);
2012 if (retval != -EAGAIN || signal_pending(current))
2013 return retval;
2014 schedule();
2015 goto retry_open;
2016 }
2017
2018 tty_add_file(tty, filp);
2019
2020 check_tty_count(tty, __func__);
2021 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2022
2023 if (tty->ops->open)
2024 retval = tty->ops->open(tty, filp);
2025 else
2026 retval = -ENODEV;
2027 filp->f_flags = saved_flags;
2028
2029 if (retval) {
2030 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2031
2032 tty_unlock(tty); /* need to call tty_release without BTM */
2033 tty_release(inode, filp);
2034 if (retval != -ERESTARTSYS)
2035 return retval;
2036
2037 if (signal_pending(current))
2038 return retval;
2039
2040 schedule();
2041 /*
2042 * Need to reset f_op in case a hangup happened.
2043 */
2044 if (tty_hung_up_p(filp))
2045 filp->f_op = &tty_fops;
2046 goto retry_open;
2047 }
2048 clear_bit(TTY_HUPPED, &tty->flags);
2049
2050 noctty = (filp->f_flags & O_NOCTTY) ||
2051 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2052 device == MKDEV(TTYAUX_MAJOR, 1) ||
2053 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2054 tty->driver->subtype == PTY_TYPE_MASTER);
2055 if (!noctty)
2056 tty_open_proc_set_tty(filp, tty);
2057 tty_unlock(tty);
2058 return 0;
2059}
2060
2061
2062
2063/**
2064 * tty_poll - check tty status
2065 * @filp: file being polled
2066 * @wait: poll wait structures to update
2067 *
2068 * Call the line discipline polling method to obtain the poll
2069 * status of the device.
2070 *
2071 * Locking: locks called line discipline but ldisc poll method
2072 * may be re-entered freely by other callers.
2073 */
2074
2075static __poll_t tty_poll(struct file *filp, poll_table *wait)
2076{
2077 struct tty_struct *tty = file_tty(filp);
2078 struct tty_ldisc *ld;
2079 __poll_t ret = 0;
2080
2081 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2082 return 0;
2083
2084 ld = tty_ldisc_ref_wait(tty);
2085 if (!ld)
2086 return hung_up_tty_poll(filp, wait);
2087 if (ld->ops->poll)
2088 ret = ld->ops->poll(tty, filp, wait);
2089 tty_ldisc_deref(ld);
2090 return ret;
2091}
2092
2093static int __tty_fasync(int fd, struct file *filp, int on)
2094{
2095 struct tty_struct *tty = file_tty(filp);
2096 unsigned long flags;
2097 int retval = 0;
2098
2099 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2100 goto out;
2101
2102 retval = fasync_helper(fd, filp, on, &tty->fasync);
2103 if (retval <= 0)
2104 goto out;
2105
2106 if (on) {
2107 enum pid_type type;
2108 struct pid *pid;
2109
2110 spin_lock_irqsave(&tty->ctrl_lock, flags);
2111 if (tty->pgrp) {
2112 pid = tty->pgrp;
2113 type = PIDTYPE_PGID;
2114 } else {
2115 pid = task_pid(current);
2116 type = PIDTYPE_PID;
2117 }
2118 get_pid(pid);
2119 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2120 __f_setown(filp, pid, type, 0);
2121 put_pid(pid);
2122 retval = 0;
2123 }
2124out:
2125 return retval;
2126}
2127
2128static int tty_fasync(int fd, struct file *filp, int on)
2129{
2130 struct tty_struct *tty = file_tty(filp);
2131 int retval = -ENOTTY;
2132
2133 tty_lock(tty);
2134 if (!tty_hung_up_p(filp))
2135 retval = __tty_fasync(fd, filp, on);
2136 tty_unlock(tty);
2137
2138 return retval;
2139}
2140
2141/**
2142 * tiocsti - fake input character
2143 * @tty: tty to fake input into
2144 * @p: pointer to character
2145 *
2146 * Fake input to a tty device. Does the necessary locking and
2147 * input management.
2148 *
2149 * FIXME: does not honour flow control ??
2150 *
2151 * Locking:
2152 * Called functions take tty_ldiscs_lock
2153 * current->signal->tty check is safe without locks
2154 *
2155 * FIXME: may race normal receive processing
2156 */
2157
2158static int tiocsti(struct tty_struct *tty, char __user *p)
2159{
2160 char ch, mbz = 0;
2161 struct tty_ldisc *ld;
2162
2163 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2164 return -EPERM;
2165 if (get_user(ch, p))
2166 return -EFAULT;
2167 tty_audit_tiocsti(tty, ch);
2168 ld = tty_ldisc_ref_wait(tty);
2169 if (!ld)
2170 return -EIO;
2171 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2172 tty_ldisc_deref(ld);
2173 return 0;
2174}
2175
2176/**
2177 * tiocgwinsz - implement window query ioctl
2178 * @tty; tty
2179 * @arg: user buffer for result
2180 *
2181 * Copies the kernel idea of the window size into the user buffer.
2182 *
2183 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2184 * is consistent.
2185 */
2186
2187static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2188{
2189 int err;
2190
2191 mutex_lock(&tty->winsize_mutex);
2192 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2193 mutex_unlock(&tty->winsize_mutex);
2194
2195 return err ? -EFAULT: 0;
2196}
2197
2198/**
2199 * tty_do_resize - resize event
2200 * @tty: tty being resized
2201 * @rows: rows (character)
2202 * @cols: cols (character)
2203 *
2204 * Update the termios variables and send the necessary signals to
2205 * peform a terminal resize correctly
2206 */
2207
2208int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2209{
2210 struct pid *pgrp;
2211
2212 /* Lock the tty */
2213 mutex_lock(&tty->winsize_mutex);
2214 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2215 goto done;
2216
2217 /* Signal the foreground process group */
2218 pgrp = tty_get_pgrp(tty);
2219 if (pgrp)
2220 kill_pgrp(pgrp, SIGWINCH, 1);
2221 put_pid(pgrp);
2222
2223 tty->winsize = *ws;
2224done:
2225 mutex_unlock(&tty->winsize_mutex);
2226 return 0;
2227}
2228EXPORT_SYMBOL(tty_do_resize);
2229
2230/**
2231 * tiocswinsz - implement window size set ioctl
2232 * @tty; tty side of tty
2233 * @arg: user buffer for result
2234 *
2235 * Copies the user idea of the window size to the kernel. Traditionally
2236 * this is just advisory information but for the Linux console it
2237 * actually has driver level meaning and triggers a VC resize.
2238 *
2239 * Locking:
2240 * Driver dependent. The default do_resize method takes the
2241 * tty termios mutex and ctrl_lock. The console takes its own lock
2242 * then calls into the default method.
2243 */
2244
2245static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2246{
2247 struct winsize tmp_ws;
2248 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2249 return -EFAULT;
2250
2251 if (tty->ops->resize)
2252 return tty->ops->resize(tty, &tmp_ws);
2253 else
2254 return tty_do_resize(tty, &tmp_ws);
2255}
2256
2257/**
2258 * tioccons - allow admin to move logical console
2259 * @file: the file to become console
2260 *
2261 * Allow the administrator to move the redirected console device
2262 *
2263 * Locking: uses redirect_lock to guard the redirect information
2264 */
2265
2266static int tioccons(struct file *file)
2267{
2268 if (!capable(CAP_SYS_ADMIN))
2269 return -EPERM;
2270 if (file->f_op->write == redirected_tty_write) {
2271 struct file *f;
2272 spin_lock(&redirect_lock);
2273 f = redirect;
2274 redirect = NULL;
2275 spin_unlock(&redirect_lock);
2276 if (f)
2277 fput(f);
2278 return 0;
2279 }
2280 spin_lock(&redirect_lock);
2281 if (redirect) {
2282 spin_unlock(&redirect_lock);
2283 return -EBUSY;
2284 }
2285 redirect = get_file(file);
2286 spin_unlock(&redirect_lock);
2287 return 0;
2288}
2289
2290/**
2291 * fionbio - non blocking ioctl
2292 * @file: file to set blocking value
2293 * @p: user parameter
2294 *
2295 * Historical tty interfaces had a blocking control ioctl before
2296 * the generic functionality existed. This piece of history is preserved
2297 * in the expected tty API of posix OS's.
2298 *
2299 * Locking: none, the open file handle ensures it won't go away.
2300 */
2301
2302static int fionbio(struct file *file, int __user *p)
2303{
2304 int nonblock;
2305
2306 if (get_user(nonblock, p))
2307 return -EFAULT;
2308
2309 spin_lock(&file->f_lock);
2310 if (nonblock)
2311 file->f_flags |= O_NONBLOCK;
2312 else
2313 file->f_flags &= ~O_NONBLOCK;
2314 spin_unlock(&file->f_lock);
2315 return 0;
2316}
2317
2318/**
2319 * tiocsetd - set line discipline
2320 * @tty: tty device
2321 * @p: pointer to user data
2322 *
2323 * Set the line discipline according to user request.
2324 *
2325 * Locking: see tty_set_ldisc, this function is just a helper
2326 */
2327
2328static int tiocsetd(struct tty_struct *tty, int __user *p)
2329{
2330 int disc;
2331 int ret;
2332
2333 if (get_user(disc, p))
2334 return -EFAULT;
2335
2336 ret = tty_set_ldisc(tty, disc);
2337
2338 return ret;
2339}
2340
2341/**
2342 * tiocgetd - get line discipline
2343 * @tty: tty device
2344 * @p: pointer to user data
2345 *
2346 * Retrieves the line discipline id directly from the ldisc.
2347 *
2348 * Locking: waits for ldisc reference (in case the line discipline
2349 * is changing or the tty is being hungup)
2350 */
2351
2352static int tiocgetd(struct tty_struct *tty, int __user *p)
2353{
2354 struct tty_ldisc *ld;
2355 int ret;
2356
2357 ld = tty_ldisc_ref_wait(tty);
2358 if (!ld)
2359 return -EIO;
2360 ret = put_user(ld->ops->num, p);
2361 tty_ldisc_deref(ld);
2362 return ret;
2363}
2364
2365/**
2366 * send_break - performed time break
2367 * @tty: device to break on
2368 * @duration: timeout in mS
2369 *
2370 * Perform a timed break on hardware that lacks its own driver level
2371 * timed break functionality.
2372 *
2373 * Locking:
2374 * atomic_write_lock serializes
2375 *
2376 */
2377
2378static int send_break(struct tty_struct *tty, unsigned int duration)
2379{
2380 int retval;
2381
2382 if (tty->ops->break_ctl == NULL)
2383 return 0;
2384
2385 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2386 retval = tty->ops->break_ctl(tty, duration);
2387 else {
2388 /* Do the work ourselves */
2389 if (tty_write_lock(tty, 0) < 0)
2390 return -EINTR;
2391 retval = tty->ops->break_ctl(tty, -1);
2392 if (retval)
2393 goto out;
2394 if (!signal_pending(current))
2395 msleep_interruptible(duration);
2396 retval = tty->ops->break_ctl(tty, 0);
2397out:
2398 tty_write_unlock(tty);
2399 if (signal_pending(current))
2400 retval = -EINTR;
2401 }
2402 return retval;
2403}
2404
2405/**
2406 * tty_tiocmget - get modem status
2407 * @tty: tty device
2408 * @file: user file pointer
2409 * @p: pointer to result
2410 *
2411 * Obtain the modem status bits from the tty driver if the feature
2412 * is supported. Return -EINVAL if it is not available.
2413 *
2414 * Locking: none (up to the driver)
2415 */
2416
2417static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2418{
2419 int retval = -EINVAL;
2420
2421 if (tty->ops->tiocmget) {
2422 retval = tty->ops->tiocmget(tty);
2423
2424 if (retval >= 0)
2425 retval = put_user(retval, p);
2426 }
2427 return retval;
2428}
2429
2430/**
2431 * tty_tiocmset - set modem status
2432 * @tty: tty device
2433 * @cmd: command - clear bits, set bits or set all
2434 * @p: pointer to desired bits
2435 *
2436 * Set the modem status bits from the tty driver if the feature
2437 * is supported. Return -EINVAL if it is not available.
2438 *
2439 * Locking: none (up to the driver)
2440 */
2441
2442static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2443 unsigned __user *p)
2444{
2445 int retval;
2446 unsigned int set, clear, val;
2447
2448 if (tty->ops->tiocmset == NULL)
2449 return -EINVAL;
2450
2451 retval = get_user(val, p);
2452 if (retval)
2453 return retval;
2454 set = clear = 0;
2455 switch (cmd) {
2456 case TIOCMBIS:
2457 set = val;
2458 break;
2459 case TIOCMBIC:
2460 clear = val;
2461 break;
2462 case TIOCMSET:
2463 set = val;
2464 clear = ~val;
2465 break;
2466 }
2467 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2468 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2469 return tty->ops->tiocmset(tty, set, clear);
2470}
2471
2472static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2473{
2474 int retval = -EINVAL;
2475 struct serial_icounter_struct icount;
2476 memset(&icount, 0, sizeof(icount));
2477 if (tty->ops->get_icount)
2478 retval = tty->ops->get_icount(tty, &icount);
2479 if (retval != 0)
2480 return retval;
2481 if (copy_to_user(arg, &icount, sizeof(icount)))
2482 return -EFAULT;
2483 return 0;
2484}
2485
2486static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2487{
2488 static DEFINE_RATELIMIT_STATE(depr_flags,
2489 DEFAULT_RATELIMIT_INTERVAL,
2490 DEFAULT_RATELIMIT_BURST);
2491 char comm[TASK_COMM_LEN];
2492 int flags;
2493
2494 if (get_user(flags, &ss->flags))
2495 return;
2496
2497 flags &= ASYNC_DEPRECATED;
2498
2499 if (flags && __ratelimit(&depr_flags))
2500 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2501 __func__, get_task_comm(comm, current), flags);
2502}
2503
2504/*
2505 * if pty, return the slave side (real_tty)
2506 * otherwise, return self
2507 */
2508static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2509{
2510 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2511 tty->driver->subtype == PTY_TYPE_MASTER)
2512 tty = tty->link;
2513 return tty;
2514}
2515
2516/*
2517 * Split this up, as gcc can choke on it otherwise..
2518 */
2519long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2520{
2521 struct tty_struct *tty = file_tty(file);
2522 struct tty_struct *real_tty;
2523 void __user *p = (void __user *)arg;
2524 int retval;
2525 struct tty_ldisc *ld;
2526
2527 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2528 return -EINVAL;
2529
2530 real_tty = tty_pair_get_tty(tty);
2531
2532 /*
2533 * Factor out some common prep work
2534 */
2535 switch (cmd) {
2536 case TIOCSETD:
2537 case TIOCSBRK:
2538 case TIOCCBRK:
2539 case TCSBRK:
2540 case TCSBRKP:
2541 retval = tty_check_change(tty);
2542 if (retval)
2543 return retval;
2544 if (cmd != TIOCCBRK) {
2545 tty_wait_until_sent(tty, 0);
2546 if (signal_pending(current))
2547 return -EINTR;
2548 }
2549 break;
2550 }
2551
2552 /*
2553 * Now do the stuff.
2554 */
2555 switch (cmd) {
2556 case TIOCSTI:
2557 return tiocsti(tty, p);
2558 case TIOCGWINSZ:
2559 return tiocgwinsz(real_tty, p);
2560 case TIOCSWINSZ:
2561 return tiocswinsz(real_tty, p);
2562 case TIOCCONS:
2563 return real_tty != tty ? -EINVAL : tioccons(file);
2564 case FIONBIO:
2565 return fionbio(file, p);
2566 case TIOCEXCL:
2567 set_bit(TTY_EXCLUSIVE, &tty->flags);
2568 return 0;
2569 case TIOCNXCL:
2570 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2571 return 0;
2572 case TIOCGEXCL:
2573 {
2574 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2575 return put_user(excl, (int __user *)p);
2576 }
2577 case TIOCGETD:
2578 return tiocgetd(tty, p);
2579 case TIOCSETD:
2580 return tiocsetd(tty, p);
2581 case TIOCVHANGUP:
2582 if (!capable(CAP_SYS_ADMIN))
2583 return -EPERM;
2584 tty_vhangup(tty);
2585 return 0;
2586 case TIOCGDEV:
2587 {
2588 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2589 return put_user(ret, (unsigned int __user *)p);
2590 }
2591 /*
2592 * Break handling
2593 */
2594 case TIOCSBRK: /* Turn break on, unconditionally */
2595 if (tty->ops->break_ctl)
2596 return tty->ops->break_ctl(tty, -1);
2597 return 0;
2598 case TIOCCBRK: /* Turn break off, unconditionally */
2599 if (tty->ops->break_ctl)
2600 return tty->ops->break_ctl(tty, 0);
2601 return 0;
2602 case TCSBRK: /* SVID version: non-zero arg --> no break */
2603 /* non-zero arg means wait for all output data
2604 * to be sent (performed above) but don't send break.
2605 * This is used by the tcdrain() termios function.
2606 */
2607 if (!arg)
2608 return send_break(tty, 250);
2609 return 0;
2610 case TCSBRKP: /* support for POSIX tcsendbreak() */
2611 return send_break(tty, arg ? arg*100 : 250);
2612
2613 case TIOCMGET:
2614 return tty_tiocmget(tty, p);
2615 case TIOCMSET:
2616 case TIOCMBIC:
2617 case TIOCMBIS:
2618 return tty_tiocmset(tty, cmd, p);
2619 case TIOCGICOUNT:
2620 retval = tty_tiocgicount(tty, p);
2621 /* For the moment allow fall through to the old method */
2622 if (retval != -EINVAL)
2623 return retval;
2624 break;
2625 case TCFLSH:
2626 switch (arg) {
2627 case TCIFLUSH:
2628 case TCIOFLUSH:
2629 /* flush tty buffer and allow ldisc to process ioctl */
2630 tty_buffer_flush(tty, NULL);
2631 break;
2632 }
2633 break;
2634 case TIOCSSERIAL:
2635 tty_warn_deprecated_flags(p);
2636 break;
2637 case TIOCGPTPEER:
2638 /* Special because the struct file is needed */
2639 return ptm_open_peer(file, tty, (int)arg);
2640 default:
2641 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2642 if (retval != -ENOIOCTLCMD)
2643 return retval;
2644 }
2645 if (tty->ops->ioctl) {
2646 retval = tty->ops->ioctl(tty, cmd, arg);
2647 if (retval != -ENOIOCTLCMD)
2648 return retval;
2649 }
2650 ld = tty_ldisc_ref_wait(tty);
2651 if (!ld)
2652 return hung_up_tty_ioctl(file, cmd, arg);
2653 retval = -EINVAL;
2654 if (ld->ops->ioctl) {
2655 retval = ld->ops->ioctl(tty, file, cmd, arg);
2656 if (retval == -ENOIOCTLCMD)
2657 retval = -ENOTTY;
2658 }
2659 tty_ldisc_deref(ld);
2660 return retval;
2661}
2662
2663#ifdef CONFIG_COMPAT
2664static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2665 unsigned long arg)
2666{
2667 struct tty_struct *tty = file_tty(file);
2668 struct tty_ldisc *ld;
2669 int retval = -ENOIOCTLCMD;
2670
2671 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2672 return -EINVAL;
2673
2674 if (tty->ops->compat_ioctl) {
2675 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2676 if (retval != -ENOIOCTLCMD)
2677 return retval;
2678 }
2679
2680 ld = tty_ldisc_ref_wait(tty);
2681 if (!ld)
2682 return hung_up_tty_compat_ioctl(file, cmd, arg);
2683 if (ld->ops->compat_ioctl)
2684 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2685 else
2686 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2687 tty_ldisc_deref(ld);
2688
2689 return retval;
2690}
2691#endif
2692
2693static int this_tty(const void *t, struct file *file, unsigned fd)
2694{
2695 if (likely(file->f_op->read != tty_read))
2696 return 0;
2697 return file_tty(file) != t ? 0 : fd + 1;
2698}
2699
2700/*
2701 * This implements the "Secure Attention Key" --- the idea is to
2702 * prevent trojan horses by killing all processes associated with this
2703 * tty when the user hits the "Secure Attention Key". Required for
2704 * super-paranoid applications --- see the Orange Book for more details.
2705 *
2706 * This code could be nicer; ideally it should send a HUP, wait a few
2707 * seconds, then send a INT, and then a KILL signal. But you then
2708 * have to coordinate with the init process, since all processes associated
2709 * with the current tty must be dead before the new getty is allowed
2710 * to spawn.
2711 *
2712 * Now, if it would be correct ;-/ The current code has a nasty hole -
2713 * it doesn't catch files in flight. We may send the descriptor to ourselves
2714 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2715 *
2716 * Nasty bug: do_SAK is being called in interrupt context. This can
2717 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2718 */
2719void __do_SAK(struct tty_struct *tty)
2720{
2721#ifdef TTY_SOFT_SAK
2722 tty_hangup(tty);
2723#else
2724 struct task_struct *g, *p;
2725 struct pid *session;
2726 int i;
2727
2728 if (!tty)
2729 return;
2730 session = tty->session;
2731
2732 tty_ldisc_flush(tty);
2733
2734 tty_driver_flush_buffer(tty);
2735
2736 read_lock(&tasklist_lock);
2737 /* Kill the entire session */
2738 do_each_pid_task(session, PIDTYPE_SID, p) {
2739 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
2740 task_pid_nr(p), p->comm);
2741 send_sig(SIGKILL, p, 1);
2742 } while_each_pid_task(session, PIDTYPE_SID, p);
2743
2744 /* Now kill any processes that happen to have the tty open */
2745 do_each_thread(g, p) {
2746 if (p->signal->tty == tty) {
2747 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
2748 task_pid_nr(p), p->comm);
2749 send_sig(SIGKILL, p, 1);
2750 continue;
2751 }
2752 task_lock(p);
2753 i = iterate_fd(p->files, 0, this_tty, tty);
2754 if (i != 0) {
2755 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
2756 task_pid_nr(p), p->comm, i - 1);
2757 force_sig(SIGKILL, p);
2758 }
2759 task_unlock(p);
2760 } while_each_thread(g, p);
2761 read_unlock(&tasklist_lock);
2762#endif
2763}
2764
2765static void do_SAK_work(struct work_struct *work)
2766{
2767 struct tty_struct *tty =
2768 container_of(work, struct tty_struct, SAK_work);
2769 __do_SAK(tty);
2770}
2771
2772/*
2773 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2774 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2775 * the values which we write to it will be identical to the values which it
2776 * already has. --akpm
2777 */
2778void do_SAK(struct tty_struct *tty)
2779{
2780 if (!tty)
2781 return;
2782 schedule_work(&tty->SAK_work);
2783}
2784
2785EXPORT_SYMBOL(do_SAK);
2786
2787static int dev_match_devt(struct device *dev, const void *data)
2788{
2789 const dev_t *devt = data;
2790 return dev->devt == *devt;
2791}
2792
2793/* Must put_device() after it's unused! */
2794static struct device *tty_get_device(struct tty_struct *tty)
2795{
2796 dev_t devt = tty_devnum(tty);
2797 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2798}
2799
2800
2801/**
2802 * alloc_tty_struct
2803 *
2804 * This subroutine allocates and initializes a tty structure.
2805 *
2806 * Locking: none - tty in question is not exposed at this point
2807 */
2808
2809struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
2810{
2811 struct tty_struct *tty;
2812
2813 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
2814 if (!tty)
2815 return NULL;
2816
2817 kref_init(&tty->kref);
2818 tty->magic = TTY_MAGIC;
2819 if (tty_ldisc_init(tty)) {
2820 kfree(tty);
2821 return NULL;
2822 }
2823 tty->session = NULL;
2824 tty->pgrp = NULL;
2825 mutex_init(&tty->legacy_mutex);
2826 mutex_init(&tty->throttle_mutex);
2827 init_rwsem(&tty->termios_rwsem);
2828 mutex_init(&tty->winsize_mutex);
2829 init_ldsem(&tty->ldisc_sem);
2830 init_waitqueue_head(&tty->write_wait);
2831 init_waitqueue_head(&tty->read_wait);
2832 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2833 mutex_init(&tty->atomic_write_lock);
2834 spin_lock_init(&tty->ctrl_lock);
2835 spin_lock_init(&tty->flow_lock);
2836 spin_lock_init(&tty->files_lock);
2837 INIT_LIST_HEAD(&tty->tty_files);
2838 INIT_WORK(&tty->SAK_work, do_SAK_work);
2839
2840 tty->driver = driver;
2841 tty->ops = driver->ops;
2842 tty->index = idx;
2843 tty_line_name(driver, idx, tty->name);
2844 tty->dev = tty_get_device(tty);
2845
2846 return tty;
2847}
2848
2849/**
2850 * tty_put_char - write one character to a tty
2851 * @tty: tty
2852 * @ch: character
2853 *
2854 * Write one byte to the tty using the provided put_char method
2855 * if present. Returns the number of characters successfully output.
2856 *
2857 * Note: the specific put_char operation in the driver layer may go
2858 * away soon. Don't call it directly, use this method
2859 */
2860
2861int tty_put_char(struct tty_struct *tty, unsigned char ch)
2862{
2863 if (tty->ops->put_char)
2864 return tty->ops->put_char(tty, ch);
2865 return tty->ops->write(tty, &ch, 1);
2866}
2867EXPORT_SYMBOL_GPL(tty_put_char);
2868
2869struct class *tty_class;
2870
2871static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
2872 unsigned int index, unsigned int count)
2873{
2874 int err;
2875
2876 /* init here, since reused cdevs cause crashes */
2877 driver->cdevs[index] = cdev_alloc();
2878 if (!driver->cdevs[index])
2879 return -ENOMEM;
2880 driver->cdevs[index]->ops = &tty_fops;
2881 driver->cdevs[index]->owner = driver->owner;
2882 err = cdev_add(driver->cdevs[index], dev, count);
2883 if (err)
2884 kobject_put(&driver->cdevs[index]->kobj);
2885 return err;
2886}
2887
2888/**
2889 * tty_register_device - register a tty device
2890 * @driver: the tty driver that describes the tty device
2891 * @index: the index in the tty driver for this tty device
2892 * @device: a struct device that is associated with this tty device.
2893 * This field is optional, if there is no known struct device
2894 * for this tty device it can be set to NULL safely.
2895 *
2896 * Returns a pointer to the struct device for this tty device
2897 * (or ERR_PTR(-EFOO) on error).
2898 *
2899 * This call is required to be made to register an individual tty device
2900 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2901 * that bit is not set, this function should not be called by a tty
2902 * driver.
2903 *
2904 * Locking: ??
2905 */
2906
2907struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2908 struct device *device)
2909{
2910 return tty_register_device_attr(driver, index, device, NULL, NULL);
2911}
2912EXPORT_SYMBOL(tty_register_device);
2913
2914static void tty_device_create_release(struct device *dev)
2915{
2916 dev_dbg(dev, "releasing...\n");
2917 kfree(dev);
2918}
2919
2920/**
2921 * tty_register_device_attr - register a tty device
2922 * @driver: the tty driver that describes the tty device
2923 * @index: the index in the tty driver for this tty device
2924 * @device: a struct device that is associated with this tty device.
2925 * This field is optional, if there is no known struct device
2926 * for this tty device it can be set to NULL safely.
2927 * @drvdata: Driver data to be set to device.
2928 * @attr_grp: Attribute group to be set on device.
2929 *
2930 * Returns a pointer to the struct device for this tty device
2931 * (or ERR_PTR(-EFOO) on error).
2932 *
2933 * This call is required to be made to register an individual tty device
2934 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2935 * that bit is not set, this function should not be called by a tty
2936 * driver.
2937 *
2938 * Locking: ??
2939 */
2940struct device *tty_register_device_attr(struct tty_driver *driver,
2941 unsigned index, struct device *device,
2942 void *drvdata,
2943 const struct attribute_group **attr_grp)
2944{
2945 char name[64];
2946 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
2947 struct ktermios *tp;
2948 struct device *dev;
2949 int retval;
2950
2951 if (index >= driver->num) {
2952 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
2953 driver->name, index);
2954 return ERR_PTR(-EINVAL);
2955 }
2956
2957 if (driver->type == TTY_DRIVER_TYPE_PTY)
2958 pty_line_name(driver, index, name);
2959 else
2960 tty_line_name(driver, index, name);
2961
2962 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
2963 if (!dev)
2964 return ERR_PTR(-ENOMEM);
2965
2966 dev->devt = devt;
2967 dev->class = tty_class;
2968 dev->parent = device;
2969 dev->release = tty_device_create_release;
2970 dev_set_name(dev, "%s", name);
2971 dev->groups = attr_grp;
2972 dev_set_drvdata(dev, drvdata);
2973
2974 dev_set_uevent_suppress(dev, 1);
2975
2976 retval = device_register(dev);
2977 if (retval)
2978 goto err_put;
2979
2980 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
2981 /*
2982 * Free any saved termios data so that the termios state is
2983 * reset when reusing a minor number.
2984 */
2985 tp = driver->termios[index];
2986 if (tp) {
2987 driver->termios[index] = NULL;
2988 kfree(tp);
2989 }
2990
2991 retval = tty_cdev_add(driver, devt, index, 1);
2992 if (retval)
2993 goto err_del;
2994 }
2995
2996 dev_set_uevent_suppress(dev, 0);
2997 kobject_uevent(&dev->kobj, KOBJ_ADD);
2998
2999 return dev;
3000
3001err_del:
3002 device_del(dev);
3003err_put:
3004 put_device(dev);
3005
3006 return ERR_PTR(retval);
3007}
3008EXPORT_SYMBOL_GPL(tty_register_device_attr);
3009
3010/**
3011 * tty_unregister_device - unregister a tty device
3012 * @driver: the tty driver that describes the tty device
3013 * @index: the index in the tty driver for this tty device
3014 *
3015 * If a tty device is registered with a call to tty_register_device() then
3016 * this function must be called when the tty device is gone.
3017 *
3018 * Locking: ??
3019 */
3020
3021void tty_unregister_device(struct tty_driver *driver, unsigned index)
3022{
3023 device_destroy(tty_class,
3024 MKDEV(driver->major, driver->minor_start) + index);
3025 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3026 cdev_del(driver->cdevs[index]);
3027 driver->cdevs[index] = NULL;
3028 }
3029}
3030EXPORT_SYMBOL(tty_unregister_device);
3031
3032/**
3033 * __tty_alloc_driver -- allocate tty driver
3034 * @lines: count of lines this driver can handle at most
3035 * @owner: module which is responsible for this driver
3036 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3037 *
3038 * This should not be called directly, some of the provided macros should be
3039 * used instead. Use IS_ERR and friends on @retval.
3040 */
3041struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3042 unsigned long flags)
3043{
3044 struct tty_driver *driver;
3045 unsigned int cdevs = 1;
3046 int err;
3047
3048 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3049 return ERR_PTR(-EINVAL);
3050
3051 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3052 if (!driver)
3053 return ERR_PTR(-ENOMEM);
3054
3055 kref_init(&driver->kref);
3056 driver->magic = TTY_DRIVER_MAGIC;
3057 driver->num = lines;
3058 driver->owner = owner;
3059 driver->flags = flags;
3060
3061 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3062 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3063 GFP_KERNEL);
3064 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3065 GFP_KERNEL);
3066 if (!driver->ttys || !driver->termios) {
3067 err = -ENOMEM;
3068 goto err_free_all;
3069 }
3070 }
3071
3072 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3073 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3074 GFP_KERNEL);
3075 if (!driver->ports) {
3076 err = -ENOMEM;
3077 goto err_free_all;
3078 }
3079 cdevs = lines;
3080 }
3081
3082 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3083 if (!driver->cdevs) {
3084 err = -ENOMEM;
3085 goto err_free_all;
3086 }
3087
3088 return driver;
3089err_free_all:
3090 kfree(driver->ports);
3091 kfree(driver->ttys);
3092 kfree(driver->termios);
3093 kfree(driver->cdevs);
3094 kfree(driver);
3095 return ERR_PTR(err);
3096}
3097EXPORT_SYMBOL(__tty_alloc_driver);
3098
3099static void destruct_tty_driver(struct kref *kref)
3100{
3101 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3102 int i;
3103 struct ktermios *tp;
3104
3105 if (driver->flags & TTY_DRIVER_INSTALLED) {
3106 for (i = 0; i < driver->num; i++) {
3107 tp = driver->termios[i];
3108 if (tp) {
3109 driver->termios[i] = NULL;
3110 kfree(tp);
3111 }
3112 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3113 tty_unregister_device(driver, i);
3114 }
3115 proc_tty_unregister_driver(driver);
3116 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3117 cdev_del(driver->cdevs[0]);
3118 }
3119 kfree(driver->cdevs);
3120 kfree(driver->ports);
3121 kfree(driver->termios);
3122 kfree(driver->ttys);
3123 kfree(driver);
3124}
3125
3126void tty_driver_kref_put(struct tty_driver *driver)
3127{
3128 kref_put(&driver->kref, destruct_tty_driver);
3129}
3130EXPORT_SYMBOL(tty_driver_kref_put);
3131
3132void tty_set_operations(struct tty_driver *driver,
3133 const struct tty_operations *op)
3134{
3135 driver->ops = op;
3136};
3137EXPORT_SYMBOL(tty_set_operations);
3138
3139void put_tty_driver(struct tty_driver *d)
3140{
3141 tty_driver_kref_put(d);
3142}
3143EXPORT_SYMBOL(put_tty_driver);
3144
3145/*
3146 * Called by a tty driver to register itself.
3147 */
3148int tty_register_driver(struct tty_driver *driver)
3149{
3150 int error;
3151 int i;
3152 dev_t dev;
3153 struct device *d;
3154
3155 if (!driver->major) {
3156 error = alloc_chrdev_region(&dev, driver->minor_start,
3157 driver->num, driver->name);
3158 if (!error) {
3159 driver->major = MAJOR(dev);
3160 driver->minor_start = MINOR(dev);
3161 }
3162 } else {
3163 dev = MKDEV(driver->major, driver->minor_start);
3164 error = register_chrdev_region(dev, driver->num, driver->name);
3165 }
3166 if (error < 0)
3167 goto err;
3168
3169 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3170 error = tty_cdev_add(driver, dev, 0, driver->num);
3171 if (error)
3172 goto err_unreg_char;
3173 }
3174
3175 mutex_lock(&tty_mutex);
3176 list_add(&driver->tty_drivers, &tty_drivers);
3177 mutex_unlock(&tty_mutex);
3178
3179 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3180 for (i = 0; i < driver->num; i++) {
3181 d = tty_register_device(driver, i, NULL);
3182 if (IS_ERR(d)) {
3183 error = PTR_ERR(d);
3184 goto err_unreg_devs;
3185 }
3186 }
3187 }
3188 proc_tty_register_driver(driver);
3189 driver->flags |= TTY_DRIVER_INSTALLED;
3190 return 0;
3191
3192err_unreg_devs:
3193 for (i--; i >= 0; i--)
3194 tty_unregister_device(driver, i);
3195
3196 mutex_lock(&tty_mutex);
3197 list_del(&driver->tty_drivers);
3198 mutex_unlock(&tty_mutex);
3199
3200err_unreg_char:
3201 unregister_chrdev_region(dev, driver->num);
3202err:
3203 return error;
3204}
3205EXPORT_SYMBOL(tty_register_driver);
3206
3207/*
3208 * Called by a tty driver to unregister itself.
3209 */
3210int tty_unregister_driver(struct tty_driver *driver)
3211{
3212#if 0
3213 /* FIXME */
3214 if (driver->refcount)
3215 return -EBUSY;
3216#endif
3217 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3218 driver->num);
3219 mutex_lock(&tty_mutex);
3220 list_del(&driver->tty_drivers);
3221 mutex_unlock(&tty_mutex);
3222 return 0;
3223}
3224
3225EXPORT_SYMBOL(tty_unregister_driver);
3226
3227dev_t tty_devnum(struct tty_struct *tty)
3228{
3229 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3230}
3231EXPORT_SYMBOL(tty_devnum);
3232
3233void tty_default_fops(struct file_operations *fops)
3234{
3235 *fops = tty_fops;
3236}
3237
3238static char *tty_devnode(struct device *dev, umode_t *mode)
3239{
3240 if (!mode)
3241 return NULL;
3242 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3243 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3244 *mode = 0666;
3245 return NULL;
3246}
3247
3248static int __init tty_class_init(void)
3249{
3250 tty_class = class_create(THIS_MODULE, "tty");
3251 if (IS_ERR(tty_class))
3252 return PTR_ERR(tty_class);
3253 tty_class->devnode = tty_devnode;
3254 return 0;
3255}
3256
3257postcore_initcall(tty_class_init);
3258
3259/* 3/2004 jmc: why do these devices exist? */
3260static struct cdev tty_cdev, console_cdev;
3261
3262static ssize_t show_cons_active(struct device *dev,
3263 struct device_attribute *attr, char *buf)
3264{
3265 struct console *cs[16];
3266 int i = 0;
3267 struct console *c;
3268 ssize_t count = 0;
3269
3270 console_lock();
3271 for_each_console(c) {
3272 if (!c->device)
3273 continue;
3274 if (!c->write)
3275 continue;
3276 if ((c->flags & CON_ENABLED) == 0)
3277 continue;
3278 cs[i++] = c;
3279 if (i >= ARRAY_SIZE(cs))
3280 break;
3281 }
3282 while (i--) {
3283 int index = cs[i]->index;
3284 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3285
3286 /* don't resolve tty0 as some programs depend on it */
3287 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3288 count += tty_line_name(drv, index, buf + count);
3289 else
3290 count += sprintf(buf + count, "%s%d",
3291 cs[i]->name, cs[i]->index);
3292
3293 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3294 }
3295 console_unlock();
3296
3297 return count;
3298}
3299static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3300
3301static struct attribute *cons_dev_attrs[] = {
3302 &dev_attr_active.attr,
3303 NULL
3304};
3305
3306ATTRIBUTE_GROUPS(cons_dev);
3307
3308static struct device *consdev;
3309
3310void console_sysfs_notify(void)
3311{
3312 if (consdev)
3313 sysfs_notify(&consdev->kobj, NULL, "active");
3314}
3315
3316/*
3317 * Ok, now we can initialize the rest of the tty devices and can count
3318 * on memory allocations, interrupts etc..
3319 */
3320int __init tty_init(void)
3321{
3322 cdev_init(&tty_cdev, &tty_fops);
3323 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3324 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3325 panic("Couldn't register /dev/tty driver\n");
3326 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3327
3328 cdev_init(&console_cdev, &console_fops);
3329 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3330 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3331 panic("Couldn't register /dev/console driver\n");
3332 consdev = device_create_with_groups(tty_class, NULL,
3333 MKDEV(TTYAUX_MAJOR, 1), NULL,
3334 cons_dev_groups, "console");
3335 if (IS_ERR(consdev))
3336 consdev = NULL;
3337
3338#ifdef CONFIG_VT
3339 vty_init(&console_fops);
3340#endif
3341 return 0;
3342}
3343
1/*
2 * Copyright (C) 1991, 1992 Linus Torvalds
3 */
4
5/*
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
8 *
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
10 *
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
16 *
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
21 *
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
25 *
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
28 * -- TYT, 1/31/92
29 *
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
33 *
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
36 *
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
39 *
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
42 *
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
45 *
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
49 *
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
52 *
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
55 *
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
58 *
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
61 *
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
65 */
66
67#include <linux/types.h>
68#include <linux/major.h>
69#include <linux/errno.h>
70#include <linux/signal.h>
71#include <linux/fcntl.h>
72#include <linux/sched.h>
73#include <linux/interrupt.h>
74#include <linux/tty.h>
75#include <linux/tty_driver.h>
76#include <linux/tty_flip.h>
77#include <linux/devpts_fs.h>
78#include <linux/file.h>
79#include <linux/fdtable.h>
80#include <linux/console.h>
81#include <linux/timer.h>
82#include <linux/ctype.h>
83#include <linux/kd.h>
84#include <linux/mm.h>
85#include <linux/string.h>
86#include <linux/slab.h>
87#include <linux/poll.h>
88#include <linux/proc_fs.h>
89#include <linux/init.h>
90#include <linux/module.h>
91#include <linux/device.h>
92#include <linux/wait.h>
93#include <linux/bitops.h>
94#include <linux/delay.h>
95#include <linux/seq_file.h>
96#include <linux/serial.h>
97#include <linux/ratelimit.h>
98
99#include <linux/uaccess.h>
100
101#include <linux/kbd_kern.h>
102#include <linux/vt_kern.h>
103#include <linux/selection.h>
104
105#include <linux/kmod.h>
106#include <linux/nsproxy.h>
107
108#undef TTY_DEBUG_HANGUP
109#ifdef TTY_DEBUG_HANGUP
110# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
111#else
112# define tty_debug_hangup(tty, f, args...) do { } while (0)
113#endif
114
115#define TTY_PARANOIA_CHECK 1
116#define CHECK_TTY_COUNT 1
117
118struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
119 .c_iflag = ICRNL | IXON,
120 .c_oflag = OPOST | ONLCR,
121 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
122 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
123 ECHOCTL | ECHOKE | IEXTEN,
124 .c_cc = INIT_C_CC,
125 .c_ispeed = 38400,
126 .c_ospeed = 38400,
127 /* .c_line = N_TTY, */
128};
129
130EXPORT_SYMBOL(tty_std_termios);
131
132/* This list gets poked at by procfs and various bits of boot up code. This
133 could do with some rationalisation such as pulling the tty proc function
134 into this file */
135
136LIST_HEAD(tty_drivers); /* linked list of tty drivers */
137
138/* Mutex to protect creating and releasing a tty */
139DEFINE_MUTEX(tty_mutex);
140
141static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
142static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
143ssize_t redirected_tty_write(struct file *, const char __user *,
144 size_t, loff_t *);
145static unsigned int tty_poll(struct file *, poll_table *);
146static int tty_open(struct inode *, struct file *);
147long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148#ifdef CONFIG_COMPAT
149static long tty_compat_ioctl(struct file *file, unsigned int cmd,
150 unsigned long arg);
151#else
152#define tty_compat_ioctl NULL
153#endif
154static int __tty_fasync(int fd, struct file *filp, int on);
155static int tty_fasync(int fd, struct file *filp, int on);
156static void release_tty(struct tty_struct *tty, int idx);
157
158/**
159 * free_tty_struct - free a disused tty
160 * @tty: tty struct to free
161 *
162 * Free the write buffers, tty queue and tty memory itself.
163 *
164 * Locking: none. Must be called after tty is definitely unused
165 */
166
167static void free_tty_struct(struct tty_struct *tty)
168{
169 tty_ldisc_deinit(tty);
170 put_device(tty->dev);
171 kfree(tty->write_buf);
172 tty->magic = 0xDEADDEAD;
173 kfree(tty);
174}
175
176static inline struct tty_struct *file_tty(struct file *file)
177{
178 return ((struct tty_file_private *)file->private_data)->tty;
179}
180
181int tty_alloc_file(struct file *file)
182{
183 struct tty_file_private *priv;
184
185 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
186 if (!priv)
187 return -ENOMEM;
188
189 file->private_data = priv;
190
191 return 0;
192}
193
194/* Associate a new file with the tty structure */
195void tty_add_file(struct tty_struct *tty, struct file *file)
196{
197 struct tty_file_private *priv = file->private_data;
198
199 priv->tty = tty;
200 priv->file = file;
201
202 spin_lock(&tty->files_lock);
203 list_add(&priv->list, &tty->tty_files);
204 spin_unlock(&tty->files_lock);
205}
206
207/**
208 * tty_free_file - free file->private_data
209 *
210 * This shall be used only for fail path handling when tty_add_file was not
211 * called yet.
212 */
213void tty_free_file(struct file *file)
214{
215 struct tty_file_private *priv = file->private_data;
216
217 file->private_data = NULL;
218 kfree(priv);
219}
220
221/* Delete file from its tty */
222static void tty_del_file(struct file *file)
223{
224 struct tty_file_private *priv = file->private_data;
225 struct tty_struct *tty = priv->tty;
226
227 spin_lock(&tty->files_lock);
228 list_del(&priv->list);
229 spin_unlock(&tty->files_lock);
230 tty_free_file(file);
231}
232
233/**
234 * tty_name - return tty naming
235 * @tty: tty structure
236 *
237 * Convert a tty structure into a name. The name reflects the kernel
238 * naming policy and if udev is in use may not reflect user space
239 *
240 * Locking: none
241 */
242
243const char *tty_name(const struct tty_struct *tty)
244{
245 if (!tty) /* Hmm. NULL pointer. That's fun. */
246 return "NULL tty";
247 return tty->name;
248}
249
250EXPORT_SYMBOL(tty_name);
251
252const char *tty_driver_name(const struct tty_struct *tty)
253{
254 if (!tty || !tty->driver)
255 return "";
256 return tty->driver->name;
257}
258
259static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
260 const char *routine)
261{
262#ifdef TTY_PARANOIA_CHECK
263 if (!tty) {
264 pr_warn("(%d:%d): %s: NULL tty\n",
265 imajor(inode), iminor(inode), routine);
266 return 1;
267 }
268 if (tty->magic != TTY_MAGIC) {
269 pr_warn("(%d:%d): %s: bad magic number\n",
270 imajor(inode), iminor(inode), routine);
271 return 1;
272 }
273#endif
274 return 0;
275}
276
277/* Caller must hold tty_lock */
278static int check_tty_count(struct tty_struct *tty, const char *routine)
279{
280#ifdef CHECK_TTY_COUNT
281 struct list_head *p;
282 int count = 0;
283
284 spin_lock(&tty->files_lock);
285 list_for_each(p, &tty->tty_files) {
286 count++;
287 }
288 spin_unlock(&tty->files_lock);
289 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
290 tty->driver->subtype == PTY_TYPE_SLAVE &&
291 tty->link && tty->link->count)
292 count++;
293 if (tty->count != count) {
294 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
295 routine, tty->count, count);
296 return count;
297 }
298#endif
299 return 0;
300}
301
302/**
303 * get_tty_driver - find device of a tty
304 * @dev_t: device identifier
305 * @index: returns the index of the tty
306 *
307 * This routine returns a tty driver structure, given a device number
308 * and also passes back the index number.
309 *
310 * Locking: caller must hold tty_mutex
311 */
312
313static struct tty_driver *get_tty_driver(dev_t device, int *index)
314{
315 struct tty_driver *p;
316
317 list_for_each_entry(p, &tty_drivers, tty_drivers) {
318 dev_t base = MKDEV(p->major, p->minor_start);
319 if (device < base || device >= base + p->num)
320 continue;
321 *index = device - base;
322 return tty_driver_kref_get(p);
323 }
324 return NULL;
325}
326
327#ifdef CONFIG_CONSOLE_POLL
328
329/**
330 * tty_find_polling_driver - find device of a polled tty
331 * @name: name string to match
332 * @line: pointer to resulting tty line nr
333 *
334 * This routine returns a tty driver structure, given a name
335 * and the condition that the tty driver is capable of polled
336 * operation.
337 */
338struct tty_driver *tty_find_polling_driver(char *name, int *line)
339{
340 struct tty_driver *p, *res = NULL;
341 int tty_line = 0;
342 int len;
343 char *str, *stp;
344
345 for (str = name; *str; str++)
346 if ((*str >= '0' && *str <= '9') || *str == ',')
347 break;
348 if (!*str)
349 return NULL;
350
351 len = str - name;
352 tty_line = simple_strtoul(str, &str, 10);
353
354 mutex_lock(&tty_mutex);
355 /* Search through the tty devices to look for a match */
356 list_for_each_entry(p, &tty_drivers, tty_drivers) {
357 if (strncmp(name, p->name, len) != 0)
358 continue;
359 stp = str;
360 if (*stp == ',')
361 stp++;
362 if (*stp == '\0')
363 stp = NULL;
364
365 if (tty_line >= 0 && tty_line < p->num && p->ops &&
366 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
367 res = tty_driver_kref_get(p);
368 *line = tty_line;
369 break;
370 }
371 }
372 mutex_unlock(&tty_mutex);
373
374 return res;
375}
376EXPORT_SYMBOL_GPL(tty_find_polling_driver);
377#endif
378
379static int is_ignored(int sig)
380{
381 return (sigismember(¤t->blocked, sig) ||
382 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
383}
384
385/**
386 * tty_check_change - check for POSIX terminal changes
387 * @tty: tty to check
388 *
389 * If we try to write to, or set the state of, a terminal and we're
390 * not in the foreground, send a SIGTTOU. If the signal is blocked or
391 * ignored, go ahead and perform the operation. (POSIX 7.2)
392 *
393 * Locking: ctrl_lock
394 */
395
396int __tty_check_change(struct tty_struct *tty, int sig)
397{
398 unsigned long flags;
399 struct pid *pgrp, *tty_pgrp;
400 int ret = 0;
401
402 if (current->signal->tty != tty)
403 return 0;
404
405 rcu_read_lock();
406 pgrp = task_pgrp(current);
407
408 spin_lock_irqsave(&tty->ctrl_lock, flags);
409 tty_pgrp = tty->pgrp;
410 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
411
412 if (tty_pgrp && pgrp != tty->pgrp) {
413 if (is_ignored(sig)) {
414 if (sig == SIGTTIN)
415 ret = -EIO;
416 } else if (is_current_pgrp_orphaned())
417 ret = -EIO;
418 else {
419 kill_pgrp(pgrp, sig, 1);
420 set_thread_flag(TIF_SIGPENDING);
421 ret = -ERESTARTSYS;
422 }
423 }
424 rcu_read_unlock();
425
426 if (!tty_pgrp)
427 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
428
429 return ret;
430}
431
432int tty_check_change(struct tty_struct *tty)
433{
434 return __tty_check_change(tty, SIGTTOU);
435}
436EXPORT_SYMBOL(tty_check_change);
437
438static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
439 size_t count, loff_t *ppos)
440{
441 return 0;
442}
443
444static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
445 size_t count, loff_t *ppos)
446{
447 return -EIO;
448}
449
450/* No kernel lock held - none needed ;) */
451static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
452{
453 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
454}
455
456static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
457 unsigned long arg)
458{
459 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
460}
461
462static long hung_up_tty_compat_ioctl(struct file *file,
463 unsigned int cmd, unsigned long arg)
464{
465 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
466}
467
468static int hung_up_tty_fasync(int fd, struct file *file, int on)
469{
470 return -ENOTTY;
471}
472
473static const struct file_operations tty_fops = {
474 .llseek = no_llseek,
475 .read = tty_read,
476 .write = tty_write,
477 .poll = tty_poll,
478 .unlocked_ioctl = tty_ioctl,
479 .compat_ioctl = tty_compat_ioctl,
480 .open = tty_open,
481 .release = tty_release,
482 .fasync = tty_fasync,
483};
484
485static const struct file_operations console_fops = {
486 .llseek = no_llseek,
487 .read = tty_read,
488 .write = redirected_tty_write,
489 .poll = tty_poll,
490 .unlocked_ioctl = tty_ioctl,
491 .compat_ioctl = tty_compat_ioctl,
492 .open = tty_open,
493 .release = tty_release,
494 .fasync = tty_fasync,
495};
496
497static const struct file_operations hung_up_tty_fops = {
498 .llseek = no_llseek,
499 .read = hung_up_tty_read,
500 .write = hung_up_tty_write,
501 .poll = hung_up_tty_poll,
502 .unlocked_ioctl = hung_up_tty_ioctl,
503 .compat_ioctl = hung_up_tty_compat_ioctl,
504 .release = tty_release,
505 .fasync = hung_up_tty_fasync,
506};
507
508static DEFINE_SPINLOCK(redirect_lock);
509static struct file *redirect;
510
511
512void proc_clear_tty(struct task_struct *p)
513{
514 unsigned long flags;
515 struct tty_struct *tty;
516 spin_lock_irqsave(&p->sighand->siglock, flags);
517 tty = p->signal->tty;
518 p->signal->tty = NULL;
519 spin_unlock_irqrestore(&p->sighand->siglock, flags);
520 tty_kref_put(tty);
521}
522
523/**
524 * proc_set_tty - set the controlling terminal
525 *
526 * Only callable by the session leader and only if it does not already have
527 * a controlling terminal.
528 *
529 * Caller must hold: tty_lock()
530 * a readlock on tasklist_lock
531 * sighand lock
532 */
533static void __proc_set_tty(struct tty_struct *tty)
534{
535 unsigned long flags;
536
537 spin_lock_irqsave(&tty->ctrl_lock, flags);
538 /*
539 * The session and fg pgrp references will be non-NULL if
540 * tiocsctty() is stealing the controlling tty
541 */
542 put_pid(tty->session);
543 put_pid(tty->pgrp);
544 tty->pgrp = get_pid(task_pgrp(current));
545 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
546 tty->session = get_pid(task_session(current));
547 if (current->signal->tty) {
548 tty_debug(tty, "current tty %s not NULL!!\n",
549 current->signal->tty->name);
550 tty_kref_put(current->signal->tty);
551 }
552 put_pid(current->signal->tty_old_pgrp);
553 current->signal->tty = tty_kref_get(tty);
554 current->signal->tty_old_pgrp = NULL;
555}
556
557static void proc_set_tty(struct tty_struct *tty)
558{
559 spin_lock_irq(¤t->sighand->siglock);
560 __proc_set_tty(tty);
561 spin_unlock_irq(¤t->sighand->siglock);
562}
563
564struct tty_struct *get_current_tty(void)
565{
566 struct tty_struct *tty;
567 unsigned long flags;
568
569 spin_lock_irqsave(¤t->sighand->siglock, flags);
570 tty = tty_kref_get(current->signal->tty);
571 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
572 return tty;
573}
574EXPORT_SYMBOL_GPL(get_current_tty);
575
576static void session_clear_tty(struct pid *session)
577{
578 struct task_struct *p;
579 do_each_pid_task(session, PIDTYPE_SID, p) {
580 proc_clear_tty(p);
581 } while_each_pid_task(session, PIDTYPE_SID, p);
582}
583
584/**
585 * tty_wakeup - request more data
586 * @tty: terminal
587 *
588 * Internal and external helper for wakeups of tty. This function
589 * informs the line discipline if present that the driver is ready
590 * to receive more output data.
591 */
592
593void tty_wakeup(struct tty_struct *tty)
594{
595 struct tty_ldisc *ld;
596
597 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
598 ld = tty_ldisc_ref(tty);
599 if (ld) {
600 if (ld->ops->write_wakeup)
601 ld->ops->write_wakeup(tty);
602 tty_ldisc_deref(ld);
603 }
604 }
605 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
606}
607
608EXPORT_SYMBOL_GPL(tty_wakeup);
609
610/**
611 * tty_signal_session_leader - sends SIGHUP to session leader
612 * @tty controlling tty
613 * @exit_session if non-zero, signal all foreground group processes
614 *
615 * Send SIGHUP and SIGCONT to the session leader and its process group.
616 * Optionally, signal all processes in the foreground process group.
617 *
618 * Returns the number of processes in the session with this tty
619 * as their controlling terminal. This value is used to drop
620 * tty references for those processes.
621 */
622static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
623{
624 struct task_struct *p;
625 int refs = 0;
626 struct pid *tty_pgrp = NULL;
627
628 read_lock(&tasklist_lock);
629 if (tty->session) {
630 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
631 spin_lock_irq(&p->sighand->siglock);
632 if (p->signal->tty == tty) {
633 p->signal->tty = NULL;
634 /* We defer the dereferences outside fo
635 the tasklist lock */
636 refs++;
637 }
638 if (!p->signal->leader) {
639 spin_unlock_irq(&p->sighand->siglock);
640 continue;
641 }
642 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
643 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
644 put_pid(p->signal->tty_old_pgrp); /* A noop */
645 spin_lock(&tty->ctrl_lock);
646 tty_pgrp = get_pid(tty->pgrp);
647 if (tty->pgrp)
648 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
649 spin_unlock(&tty->ctrl_lock);
650 spin_unlock_irq(&p->sighand->siglock);
651 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
652 }
653 read_unlock(&tasklist_lock);
654
655 if (tty_pgrp) {
656 if (exit_session)
657 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
658 put_pid(tty_pgrp);
659 }
660
661 return refs;
662}
663
664/**
665 * __tty_hangup - actual handler for hangup events
666 * @work: tty device
667 *
668 * This can be called by a "kworker" kernel thread. That is process
669 * synchronous but doesn't hold any locks, so we need to make sure we
670 * have the appropriate locks for what we're doing.
671 *
672 * The hangup event clears any pending redirections onto the hung up
673 * device. It ensures future writes will error and it does the needed
674 * line discipline hangup and signal delivery. The tty object itself
675 * remains intact.
676 *
677 * Locking:
678 * BTM
679 * redirect lock for undoing redirection
680 * file list lock for manipulating list of ttys
681 * tty_ldiscs_lock from called functions
682 * termios_rwsem resetting termios data
683 * tasklist_lock to walk task list for hangup event
684 * ->siglock to protect ->signal/->sighand
685 */
686static void __tty_hangup(struct tty_struct *tty, int exit_session)
687{
688 struct file *cons_filp = NULL;
689 struct file *filp, *f = NULL;
690 struct tty_file_private *priv;
691 int closecount = 0, n;
692 int refs;
693
694 if (!tty)
695 return;
696
697
698 spin_lock(&redirect_lock);
699 if (redirect && file_tty(redirect) == tty) {
700 f = redirect;
701 redirect = NULL;
702 }
703 spin_unlock(&redirect_lock);
704
705 tty_lock(tty);
706
707 if (test_bit(TTY_HUPPED, &tty->flags)) {
708 tty_unlock(tty);
709 return;
710 }
711
712 /* inuse_filps is protected by the single tty lock,
713 this really needs to change if we want to flush the
714 workqueue with the lock held */
715 check_tty_count(tty, "tty_hangup");
716
717 spin_lock(&tty->files_lock);
718 /* This breaks for file handles being sent over AF_UNIX sockets ? */
719 list_for_each_entry(priv, &tty->tty_files, list) {
720 filp = priv->file;
721 if (filp->f_op->write == redirected_tty_write)
722 cons_filp = filp;
723 if (filp->f_op->write != tty_write)
724 continue;
725 closecount++;
726 __tty_fasync(-1, filp, 0); /* can't block */
727 filp->f_op = &hung_up_tty_fops;
728 }
729 spin_unlock(&tty->files_lock);
730
731 refs = tty_signal_session_leader(tty, exit_session);
732 /* Account for the p->signal references we killed */
733 while (refs--)
734 tty_kref_put(tty);
735
736 tty_ldisc_hangup(tty, cons_filp != NULL);
737
738 spin_lock_irq(&tty->ctrl_lock);
739 clear_bit(TTY_THROTTLED, &tty->flags);
740 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
741 put_pid(tty->session);
742 put_pid(tty->pgrp);
743 tty->session = NULL;
744 tty->pgrp = NULL;
745 tty->ctrl_status = 0;
746 spin_unlock_irq(&tty->ctrl_lock);
747
748 /*
749 * If one of the devices matches a console pointer, we
750 * cannot just call hangup() because that will cause
751 * tty->count and state->count to go out of sync.
752 * So we just call close() the right number of times.
753 */
754 if (cons_filp) {
755 if (tty->ops->close)
756 for (n = 0; n < closecount; n++)
757 tty->ops->close(tty, cons_filp);
758 } else if (tty->ops->hangup)
759 tty->ops->hangup(tty);
760 /*
761 * We don't want to have driver/ldisc interactions beyond the ones
762 * we did here. The driver layer expects no calls after ->hangup()
763 * from the ldisc side, which is now guaranteed.
764 */
765 set_bit(TTY_HUPPED, &tty->flags);
766 tty_unlock(tty);
767
768 if (f)
769 fput(f);
770}
771
772static void do_tty_hangup(struct work_struct *work)
773{
774 struct tty_struct *tty =
775 container_of(work, struct tty_struct, hangup_work);
776
777 __tty_hangup(tty, 0);
778}
779
780/**
781 * tty_hangup - trigger a hangup event
782 * @tty: tty to hangup
783 *
784 * A carrier loss (virtual or otherwise) has occurred on this like
785 * schedule a hangup sequence to run after this event.
786 */
787
788void tty_hangup(struct tty_struct *tty)
789{
790 tty_debug_hangup(tty, "hangup\n");
791 schedule_work(&tty->hangup_work);
792}
793
794EXPORT_SYMBOL(tty_hangup);
795
796/**
797 * tty_vhangup - process vhangup
798 * @tty: tty to hangup
799 *
800 * The user has asked via system call for the terminal to be hung up.
801 * We do this synchronously so that when the syscall returns the process
802 * is complete. That guarantee is necessary for security reasons.
803 */
804
805void tty_vhangup(struct tty_struct *tty)
806{
807 tty_debug_hangup(tty, "vhangup\n");
808 __tty_hangup(tty, 0);
809}
810
811EXPORT_SYMBOL(tty_vhangup);
812
813
814/**
815 * tty_vhangup_self - process vhangup for own ctty
816 *
817 * Perform a vhangup on the current controlling tty
818 */
819
820void tty_vhangup_self(void)
821{
822 struct tty_struct *tty;
823
824 tty = get_current_tty();
825 if (tty) {
826 tty_vhangup(tty);
827 tty_kref_put(tty);
828 }
829}
830
831/**
832 * tty_vhangup_session - hangup session leader exit
833 * @tty: tty to hangup
834 *
835 * The session leader is exiting and hanging up its controlling terminal.
836 * Every process in the foreground process group is signalled SIGHUP.
837 *
838 * We do this synchronously so that when the syscall returns the process
839 * is complete. That guarantee is necessary for security reasons.
840 */
841
842static void tty_vhangup_session(struct tty_struct *tty)
843{
844 tty_debug_hangup(tty, "session hangup\n");
845 __tty_hangup(tty, 1);
846}
847
848/**
849 * tty_hung_up_p - was tty hung up
850 * @filp: file pointer of tty
851 *
852 * Return true if the tty has been subject to a vhangup or a carrier
853 * loss
854 */
855
856int tty_hung_up_p(struct file *filp)
857{
858 return (filp->f_op == &hung_up_tty_fops);
859}
860
861EXPORT_SYMBOL(tty_hung_up_p);
862
863/**
864 * disassociate_ctty - disconnect controlling tty
865 * @on_exit: true if exiting so need to "hang up" the session
866 *
867 * This function is typically called only by the session leader, when
868 * it wants to disassociate itself from its controlling tty.
869 *
870 * It performs the following functions:
871 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
872 * (2) Clears the tty from being controlling the session
873 * (3) Clears the controlling tty for all processes in the
874 * session group.
875 *
876 * The argument on_exit is set to 1 if called when a process is
877 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
878 *
879 * Locking:
880 * BTM is taken for hysterical raisins, and held when
881 * called from no_tty().
882 * tty_mutex is taken to protect tty
883 * ->siglock is taken to protect ->signal/->sighand
884 * tasklist_lock is taken to walk process list for sessions
885 * ->siglock is taken to protect ->signal/->sighand
886 */
887
888void disassociate_ctty(int on_exit)
889{
890 struct tty_struct *tty;
891
892 if (!current->signal->leader)
893 return;
894
895 tty = get_current_tty();
896 if (tty) {
897 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
898 tty_vhangup_session(tty);
899 } else {
900 struct pid *tty_pgrp = tty_get_pgrp(tty);
901 if (tty_pgrp) {
902 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
903 if (!on_exit)
904 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
905 put_pid(tty_pgrp);
906 }
907 }
908 tty_kref_put(tty);
909
910 } else if (on_exit) {
911 struct pid *old_pgrp;
912 spin_lock_irq(¤t->sighand->siglock);
913 old_pgrp = current->signal->tty_old_pgrp;
914 current->signal->tty_old_pgrp = NULL;
915 spin_unlock_irq(¤t->sighand->siglock);
916 if (old_pgrp) {
917 kill_pgrp(old_pgrp, SIGHUP, on_exit);
918 kill_pgrp(old_pgrp, SIGCONT, on_exit);
919 put_pid(old_pgrp);
920 }
921 return;
922 }
923
924 spin_lock_irq(¤t->sighand->siglock);
925 put_pid(current->signal->tty_old_pgrp);
926 current->signal->tty_old_pgrp = NULL;
927
928 tty = tty_kref_get(current->signal->tty);
929 if (tty) {
930 unsigned long flags;
931 spin_lock_irqsave(&tty->ctrl_lock, flags);
932 put_pid(tty->session);
933 put_pid(tty->pgrp);
934 tty->session = NULL;
935 tty->pgrp = NULL;
936 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
937 tty_kref_put(tty);
938 } else
939 tty_debug_hangup(tty, "no current tty\n");
940
941 spin_unlock_irq(¤t->sighand->siglock);
942 /* Now clear signal->tty under the lock */
943 read_lock(&tasklist_lock);
944 session_clear_tty(task_session(current));
945 read_unlock(&tasklist_lock);
946}
947
948/**
949 *
950 * no_tty - Ensure the current process does not have a controlling tty
951 */
952void no_tty(void)
953{
954 /* FIXME: Review locking here. The tty_lock never covered any race
955 between a new association and proc_clear_tty but possible we need
956 to protect against this anyway */
957 struct task_struct *tsk = current;
958 disassociate_ctty(0);
959 proc_clear_tty(tsk);
960}
961
962
963/**
964 * stop_tty - propagate flow control
965 * @tty: tty to stop
966 *
967 * Perform flow control to the driver. May be called
968 * on an already stopped device and will not re-call the driver
969 * method.
970 *
971 * This functionality is used by both the line disciplines for
972 * halting incoming flow and by the driver. It may therefore be
973 * called from any context, may be under the tty atomic_write_lock
974 * but not always.
975 *
976 * Locking:
977 * flow_lock
978 */
979
980void __stop_tty(struct tty_struct *tty)
981{
982 if (tty->stopped)
983 return;
984 tty->stopped = 1;
985 if (tty->ops->stop)
986 tty->ops->stop(tty);
987}
988
989void stop_tty(struct tty_struct *tty)
990{
991 unsigned long flags;
992
993 spin_lock_irqsave(&tty->flow_lock, flags);
994 __stop_tty(tty);
995 spin_unlock_irqrestore(&tty->flow_lock, flags);
996}
997EXPORT_SYMBOL(stop_tty);
998
999/**
1000 * start_tty - propagate flow control
1001 * @tty: tty to start
1002 *
1003 * Start a tty that has been stopped if at all possible. If this
1004 * tty was previous stopped and is now being started, the driver
1005 * start method is invoked and the line discipline woken.
1006 *
1007 * Locking:
1008 * flow_lock
1009 */
1010
1011void __start_tty(struct tty_struct *tty)
1012{
1013 if (!tty->stopped || tty->flow_stopped)
1014 return;
1015 tty->stopped = 0;
1016 if (tty->ops->start)
1017 tty->ops->start(tty);
1018 tty_wakeup(tty);
1019}
1020
1021void start_tty(struct tty_struct *tty)
1022{
1023 unsigned long flags;
1024
1025 spin_lock_irqsave(&tty->flow_lock, flags);
1026 __start_tty(tty);
1027 spin_unlock_irqrestore(&tty->flow_lock, flags);
1028}
1029EXPORT_SYMBOL(start_tty);
1030
1031static void tty_update_time(struct timespec *time)
1032{
1033 unsigned long sec = get_seconds();
1034
1035 /*
1036 * We only care if the two values differ in anything other than the
1037 * lower three bits (i.e every 8 seconds). If so, then we can update
1038 * the time of the tty device, otherwise it could be construded as a
1039 * security leak to let userspace know the exact timing of the tty.
1040 */
1041 if ((sec ^ time->tv_sec) & ~7)
1042 time->tv_sec = sec;
1043}
1044
1045/**
1046 * tty_read - read method for tty device files
1047 * @file: pointer to tty file
1048 * @buf: user buffer
1049 * @count: size of user buffer
1050 * @ppos: unused
1051 *
1052 * Perform the read system call function on this terminal device. Checks
1053 * for hung up devices before calling the line discipline method.
1054 *
1055 * Locking:
1056 * Locks the line discipline internally while needed. Multiple
1057 * read calls may be outstanding in parallel.
1058 */
1059
1060static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1061 loff_t *ppos)
1062{
1063 int i;
1064 struct inode *inode = file_inode(file);
1065 struct tty_struct *tty = file_tty(file);
1066 struct tty_ldisc *ld;
1067
1068 if (tty_paranoia_check(tty, inode, "tty_read"))
1069 return -EIO;
1070 if (!tty || tty_io_error(tty))
1071 return -EIO;
1072
1073 /* We want to wait for the line discipline to sort out in this
1074 situation */
1075 ld = tty_ldisc_ref_wait(tty);
1076 if (!ld)
1077 return hung_up_tty_read(file, buf, count, ppos);
1078 if (ld->ops->read)
1079 i = ld->ops->read(tty, file, buf, count);
1080 else
1081 i = -EIO;
1082 tty_ldisc_deref(ld);
1083
1084 if (i > 0)
1085 tty_update_time(&inode->i_atime);
1086
1087 return i;
1088}
1089
1090static void tty_write_unlock(struct tty_struct *tty)
1091{
1092 mutex_unlock(&tty->atomic_write_lock);
1093 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1094}
1095
1096static int tty_write_lock(struct tty_struct *tty, int ndelay)
1097{
1098 if (!mutex_trylock(&tty->atomic_write_lock)) {
1099 if (ndelay)
1100 return -EAGAIN;
1101 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1102 return -ERESTARTSYS;
1103 }
1104 return 0;
1105}
1106
1107/*
1108 * Split writes up in sane blocksizes to avoid
1109 * denial-of-service type attacks
1110 */
1111static inline ssize_t do_tty_write(
1112 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1113 struct tty_struct *tty,
1114 struct file *file,
1115 const char __user *buf,
1116 size_t count)
1117{
1118 ssize_t ret, written = 0;
1119 unsigned int chunk;
1120
1121 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1122 if (ret < 0)
1123 return ret;
1124
1125 /*
1126 * We chunk up writes into a temporary buffer. This
1127 * simplifies low-level drivers immensely, since they
1128 * don't have locking issues and user mode accesses.
1129 *
1130 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1131 * big chunk-size..
1132 *
1133 * The default chunk-size is 2kB, because the NTTY
1134 * layer has problems with bigger chunks. It will
1135 * claim to be able to handle more characters than
1136 * it actually does.
1137 *
1138 * FIXME: This can probably go away now except that 64K chunks
1139 * are too likely to fail unless switched to vmalloc...
1140 */
1141 chunk = 2048;
1142 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1143 chunk = 65536;
1144 if (count < chunk)
1145 chunk = count;
1146
1147 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1148 if (tty->write_cnt < chunk) {
1149 unsigned char *buf_chunk;
1150
1151 if (chunk < 1024)
1152 chunk = 1024;
1153
1154 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1155 if (!buf_chunk) {
1156 ret = -ENOMEM;
1157 goto out;
1158 }
1159 kfree(tty->write_buf);
1160 tty->write_cnt = chunk;
1161 tty->write_buf = buf_chunk;
1162 }
1163
1164 /* Do the write .. */
1165 for (;;) {
1166 size_t size = count;
1167 if (size > chunk)
1168 size = chunk;
1169 ret = -EFAULT;
1170 if (copy_from_user(tty->write_buf, buf, size))
1171 break;
1172 ret = write(tty, file, tty->write_buf, size);
1173 if (ret <= 0)
1174 break;
1175 written += ret;
1176 buf += ret;
1177 count -= ret;
1178 if (!count)
1179 break;
1180 ret = -ERESTARTSYS;
1181 if (signal_pending(current))
1182 break;
1183 cond_resched();
1184 }
1185 if (written) {
1186 tty_update_time(&file_inode(file)->i_mtime);
1187 ret = written;
1188 }
1189out:
1190 tty_write_unlock(tty);
1191 return ret;
1192}
1193
1194/**
1195 * tty_write_message - write a message to a certain tty, not just the console.
1196 * @tty: the destination tty_struct
1197 * @msg: the message to write
1198 *
1199 * This is used for messages that need to be redirected to a specific tty.
1200 * We don't put it into the syslog queue right now maybe in the future if
1201 * really needed.
1202 *
1203 * We must still hold the BTM and test the CLOSING flag for the moment.
1204 */
1205
1206void tty_write_message(struct tty_struct *tty, char *msg)
1207{
1208 if (tty) {
1209 mutex_lock(&tty->atomic_write_lock);
1210 tty_lock(tty);
1211 if (tty->ops->write && tty->count > 0)
1212 tty->ops->write(tty, msg, strlen(msg));
1213 tty_unlock(tty);
1214 tty_write_unlock(tty);
1215 }
1216 return;
1217}
1218
1219
1220/**
1221 * tty_write - write method for tty device file
1222 * @file: tty file pointer
1223 * @buf: user data to write
1224 * @count: bytes to write
1225 * @ppos: unused
1226 *
1227 * Write data to a tty device via the line discipline.
1228 *
1229 * Locking:
1230 * Locks the line discipline as required
1231 * Writes to the tty driver are serialized by the atomic_write_lock
1232 * and are then processed in chunks to the device. The line discipline
1233 * write method will not be invoked in parallel for each device.
1234 */
1235
1236static ssize_t tty_write(struct file *file, const char __user *buf,
1237 size_t count, loff_t *ppos)
1238{
1239 struct tty_struct *tty = file_tty(file);
1240 struct tty_ldisc *ld;
1241 ssize_t ret;
1242
1243 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1244 return -EIO;
1245 if (!tty || !tty->ops->write || tty_io_error(tty))
1246 return -EIO;
1247 /* Short term debug to catch buggy drivers */
1248 if (tty->ops->write_room == NULL)
1249 tty_err(tty, "missing write_room method\n");
1250 ld = tty_ldisc_ref_wait(tty);
1251 if (!ld)
1252 return hung_up_tty_write(file, buf, count, ppos);
1253 if (!ld->ops->write)
1254 ret = -EIO;
1255 else
1256 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1257 tty_ldisc_deref(ld);
1258 return ret;
1259}
1260
1261ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1262 size_t count, loff_t *ppos)
1263{
1264 struct file *p = NULL;
1265
1266 spin_lock(&redirect_lock);
1267 if (redirect)
1268 p = get_file(redirect);
1269 spin_unlock(&redirect_lock);
1270
1271 if (p) {
1272 ssize_t res;
1273 res = vfs_write(p, buf, count, &p->f_pos);
1274 fput(p);
1275 return res;
1276 }
1277 return tty_write(file, buf, count, ppos);
1278}
1279
1280/**
1281 * tty_send_xchar - send priority character
1282 *
1283 * Send a high priority character to the tty even if stopped
1284 *
1285 * Locking: none for xchar method, write ordering for write method.
1286 */
1287
1288int tty_send_xchar(struct tty_struct *tty, char ch)
1289{
1290 int was_stopped = tty->stopped;
1291
1292 if (tty->ops->send_xchar) {
1293 down_read(&tty->termios_rwsem);
1294 tty->ops->send_xchar(tty, ch);
1295 up_read(&tty->termios_rwsem);
1296 return 0;
1297 }
1298
1299 if (tty_write_lock(tty, 0) < 0)
1300 return -ERESTARTSYS;
1301
1302 down_read(&tty->termios_rwsem);
1303 if (was_stopped)
1304 start_tty(tty);
1305 tty->ops->write(tty, &ch, 1);
1306 if (was_stopped)
1307 stop_tty(tty);
1308 up_read(&tty->termios_rwsem);
1309 tty_write_unlock(tty);
1310 return 0;
1311}
1312
1313static char ptychar[] = "pqrstuvwxyzabcde";
1314
1315/**
1316 * pty_line_name - generate name for a pty
1317 * @driver: the tty driver in use
1318 * @index: the minor number
1319 * @p: output buffer of at least 6 bytes
1320 *
1321 * Generate a name from a driver reference and write it to the output
1322 * buffer.
1323 *
1324 * Locking: None
1325 */
1326static void pty_line_name(struct tty_driver *driver, int index, char *p)
1327{
1328 int i = index + driver->name_base;
1329 /* ->name is initialized to "ttyp", but "tty" is expected */
1330 sprintf(p, "%s%c%x",
1331 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1332 ptychar[i >> 4 & 0xf], i & 0xf);
1333}
1334
1335/**
1336 * tty_line_name - generate name for a tty
1337 * @driver: the tty driver in use
1338 * @index: the minor number
1339 * @p: output buffer of at least 7 bytes
1340 *
1341 * Generate a name from a driver reference and write it to the output
1342 * buffer.
1343 *
1344 * Locking: None
1345 */
1346static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1347{
1348 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1349 return sprintf(p, "%s", driver->name);
1350 else
1351 return sprintf(p, "%s%d", driver->name,
1352 index + driver->name_base);
1353}
1354
1355/**
1356 * tty_driver_lookup_tty() - find an existing tty, if any
1357 * @driver: the driver for the tty
1358 * @idx: the minor number
1359 *
1360 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1361 * driver lookup() method returns an error.
1362 *
1363 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1364 */
1365static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1366 struct file *file, int idx)
1367{
1368 struct tty_struct *tty;
1369
1370 if (driver->ops->lookup)
1371 tty = driver->ops->lookup(driver, file, idx);
1372 else
1373 tty = driver->ttys[idx];
1374
1375 if (!IS_ERR(tty))
1376 tty_kref_get(tty);
1377 return tty;
1378}
1379
1380/**
1381 * tty_init_termios - helper for termios setup
1382 * @tty: the tty to set up
1383 *
1384 * Initialise the termios structures for this tty. Thus runs under
1385 * the tty_mutex currently so we can be relaxed about ordering.
1386 */
1387
1388void tty_init_termios(struct tty_struct *tty)
1389{
1390 struct ktermios *tp;
1391 int idx = tty->index;
1392
1393 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1394 tty->termios = tty->driver->init_termios;
1395 else {
1396 /* Check for lazy saved data */
1397 tp = tty->driver->termios[idx];
1398 if (tp != NULL) {
1399 tty->termios = *tp;
1400 tty->termios.c_line = tty->driver->init_termios.c_line;
1401 } else
1402 tty->termios = tty->driver->init_termios;
1403 }
1404 /* Compatibility until drivers always set this */
1405 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1406 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1407}
1408EXPORT_SYMBOL_GPL(tty_init_termios);
1409
1410int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1411{
1412 tty_init_termios(tty);
1413 tty_driver_kref_get(driver);
1414 tty->count++;
1415 driver->ttys[tty->index] = tty;
1416 return 0;
1417}
1418EXPORT_SYMBOL_GPL(tty_standard_install);
1419
1420/**
1421 * tty_driver_install_tty() - install a tty entry in the driver
1422 * @driver: the driver for the tty
1423 * @tty: the tty
1424 *
1425 * Install a tty object into the driver tables. The tty->index field
1426 * will be set by the time this is called. This method is responsible
1427 * for ensuring any need additional structures are allocated and
1428 * configured.
1429 *
1430 * Locking: tty_mutex for now
1431 */
1432static int tty_driver_install_tty(struct tty_driver *driver,
1433 struct tty_struct *tty)
1434{
1435 return driver->ops->install ? driver->ops->install(driver, tty) :
1436 tty_standard_install(driver, tty);
1437}
1438
1439/**
1440 * tty_driver_remove_tty() - remove a tty from the driver tables
1441 * @driver: the driver for the tty
1442 * @idx: the minor number
1443 *
1444 * Remvoe a tty object from the driver tables. The tty->index field
1445 * will be set by the time this is called.
1446 *
1447 * Locking: tty_mutex for now
1448 */
1449static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1450{
1451 if (driver->ops->remove)
1452 driver->ops->remove(driver, tty);
1453 else
1454 driver->ttys[tty->index] = NULL;
1455}
1456
1457/*
1458 * tty_reopen() - fast re-open of an open tty
1459 * @tty - the tty to open
1460 *
1461 * Return 0 on success, -errno on error.
1462 * Re-opens on master ptys are not allowed and return -EIO.
1463 *
1464 * Locking: Caller must hold tty_lock
1465 */
1466static int tty_reopen(struct tty_struct *tty)
1467{
1468 struct tty_driver *driver = tty->driver;
1469
1470 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1471 driver->subtype == PTY_TYPE_MASTER)
1472 return -EIO;
1473
1474 if (!tty->count)
1475 return -EAGAIN;
1476
1477 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1478 return -EBUSY;
1479
1480 tty->count++;
1481
1482 if (!tty->ldisc)
1483 return tty_ldisc_reinit(tty, tty->termios.c_line);
1484
1485 return 0;
1486}
1487
1488/**
1489 * tty_init_dev - initialise a tty device
1490 * @driver: tty driver we are opening a device on
1491 * @idx: device index
1492 * @ret_tty: returned tty structure
1493 *
1494 * Prepare a tty device. This may not be a "new" clean device but
1495 * could also be an active device. The pty drivers require special
1496 * handling because of this.
1497 *
1498 * Locking:
1499 * The function is called under the tty_mutex, which
1500 * protects us from the tty struct or driver itself going away.
1501 *
1502 * On exit the tty device has the line discipline attached and
1503 * a reference count of 1. If a pair was created for pty/tty use
1504 * and the other was a pty master then it too has a reference count of 1.
1505 *
1506 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1507 * failed open. The new code protects the open with a mutex, so it's
1508 * really quite straightforward. The mutex locking can probably be
1509 * relaxed for the (most common) case of reopening a tty.
1510 */
1511
1512struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1513{
1514 struct tty_struct *tty;
1515 int retval;
1516
1517 /*
1518 * First time open is complex, especially for PTY devices.
1519 * This code guarantees that either everything succeeds and the
1520 * TTY is ready for operation, or else the table slots are vacated
1521 * and the allocated memory released. (Except that the termios
1522 * and locked termios may be retained.)
1523 */
1524
1525 if (!try_module_get(driver->owner))
1526 return ERR_PTR(-ENODEV);
1527
1528 tty = alloc_tty_struct(driver, idx);
1529 if (!tty) {
1530 retval = -ENOMEM;
1531 goto err_module_put;
1532 }
1533
1534 tty_lock(tty);
1535 retval = tty_driver_install_tty(driver, tty);
1536 if (retval < 0)
1537 goto err_free_tty;
1538
1539 if (!tty->port)
1540 tty->port = driver->ports[idx];
1541
1542 WARN_RATELIMIT(!tty->port,
1543 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1544 __func__, tty->driver->name);
1545
1546 tty->port->itty = tty;
1547
1548 /*
1549 * Structures all installed ... call the ldisc open routines.
1550 * If we fail here just call release_tty to clean up. No need
1551 * to decrement the use counts, as release_tty doesn't care.
1552 */
1553 retval = tty_ldisc_setup(tty, tty->link);
1554 if (retval)
1555 goto err_release_tty;
1556 /* Return the tty locked so that it cannot vanish under the caller */
1557 return tty;
1558
1559err_free_tty:
1560 tty_unlock(tty);
1561 free_tty_struct(tty);
1562err_module_put:
1563 module_put(driver->owner);
1564 return ERR_PTR(retval);
1565
1566 /* call the tty release_tty routine to clean out this slot */
1567err_release_tty:
1568 tty_unlock(tty);
1569 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1570 retval, idx);
1571 release_tty(tty, idx);
1572 return ERR_PTR(retval);
1573}
1574
1575static void tty_free_termios(struct tty_struct *tty)
1576{
1577 struct ktermios *tp;
1578 int idx = tty->index;
1579
1580 /* If the port is going to reset then it has no termios to save */
1581 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1582 return;
1583
1584 /* Stash the termios data */
1585 tp = tty->driver->termios[idx];
1586 if (tp == NULL) {
1587 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1588 if (tp == NULL)
1589 return;
1590 tty->driver->termios[idx] = tp;
1591 }
1592 *tp = tty->termios;
1593}
1594
1595/**
1596 * tty_flush_works - flush all works of a tty/pty pair
1597 * @tty: tty device to flush works for (or either end of a pty pair)
1598 *
1599 * Sync flush all works belonging to @tty (and the 'other' tty).
1600 */
1601static void tty_flush_works(struct tty_struct *tty)
1602{
1603 flush_work(&tty->SAK_work);
1604 flush_work(&tty->hangup_work);
1605 if (tty->link) {
1606 flush_work(&tty->link->SAK_work);
1607 flush_work(&tty->link->hangup_work);
1608 }
1609}
1610
1611/**
1612 * release_one_tty - release tty structure memory
1613 * @kref: kref of tty we are obliterating
1614 *
1615 * Releases memory associated with a tty structure, and clears out the
1616 * driver table slots. This function is called when a device is no longer
1617 * in use. It also gets called when setup of a device fails.
1618 *
1619 * Locking:
1620 * takes the file list lock internally when working on the list
1621 * of ttys that the driver keeps.
1622 *
1623 * This method gets called from a work queue so that the driver private
1624 * cleanup ops can sleep (needed for USB at least)
1625 */
1626static void release_one_tty(struct work_struct *work)
1627{
1628 struct tty_struct *tty =
1629 container_of(work, struct tty_struct, hangup_work);
1630 struct tty_driver *driver = tty->driver;
1631 struct module *owner = driver->owner;
1632
1633 if (tty->ops->cleanup)
1634 tty->ops->cleanup(tty);
1635
1636 tty->magic = 0;
1637 tty_driver_kref_put(driver);
1638 module_put(owner);
1639
1640 spin_lock(&tty->files_lock);
1641 list_del_init(&tty->tty_files);
1642 spin_unlock(&tty->files_lock);
1643
1644 put_pid(tty->pgrp);
1645 put_pid(tty->session);
1646 free_tty_struct(tty);
1647}
1648
1649static void queue_release_one_tty(struct kref *kref)
1650{
1651 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1652
1653 /* The hangup queue is now free so we can reuse it rather than
1654 waste a chunk of memory for each port */
1655 INIT_WORK(&tty->hangup_work, release_one_tty);
1656 schedule_work(&tty->hangup_work);
1657}
1658
1659/**
1660 * tty_kref_put - release a tty kref
1661 * @tty: tty device
1662 *
1663 * Release a reference to a tty device and if need be let the kref
1664 * layer destruct the object for us
1665 */
1666
1667void tty_kref_put(struct tty_struct *tty)
1668{
1669 if (tty)
1670 kref_put(&tty->kref, queue_release_one_tty);
1671}
1672EXPORT_SYMBOL(tty_kref_put);
1673
1674/**
1675 * release_tty - release tty structure memory
1676 *
1677 * Release both @tty and a possible linked partner (think pty pair),
1678 * and decrement the refcount of the backing module.
1679 *
1680 * Locking:
1681 * tty_mutex
1682 * takes the file list lock internally when working on the list
1683 * of ttys that the driver keeps.
1684 *
1685 */
1686static void release_tty(struct tty_struct *tty, int idx)
1687{
1688 /* This should always be true but check for the moment */
1689 WARN_ON(tty->index != idx);
1690 WARN_ON(!mutex_is_locked(&tty_mutex));
1691 if (tty->ops->shutdown)
1692 tty->ops->shutdown(tty);
1693 tty_free_termios(tty);
1694 tty_driver_remove_tty(tty->driver, tty);
1695 tty->port->itty = NULL;
1696 if (tty->link)
1697 tty->link->port->itty = NULL;
1698 tty_buffer_cancel_work(tty->port);
1699
1700 tty_kref_put(tty->link);
1701 tty_kref_put(tty);
1702}
1703
1704/**
1705 * tty_release_checks - check a tty before real release
1706 * @tty: tty to check
1707 * @o_tty: link of @tty (if any)
1708 * @idx: index of the tty
1709 *
1710 * Performs some paranoid checking before true release of the @tty.
1711 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1712 */
1713static int tty_release_checks(struct tty_struct *tty, int idx)
1714{
1715#ifdef TTY_PARANOIA_CHECK
1716 if (idx < 0 || idx >= tty->driver->num) {
1717 tty_debug(tty, "bad idx %d\n", idx);
1718 return -1;
1719 }
1720
1721 /* not much to check for devpts */
1722 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1723 return 0;
1724
1725 if (tty != tty->driver->ttys[idx]) {
1726 tty_debug(tty, "bad driver table[%d] = %p\n",
1727 idx, tty->driver->ttys[idx]);
1728 return -1;
1729 }
1730 if (tty->driver->other) {
1731 struct tty_struct *o_tty = tty->link;
1732
1733 if (o_tty != tty->driver->other->ttys[idx]) {
1734 tty_debug(tty, "bad other table[%d] = %p\n",
1735 idx, tty->driver->other->ttys[idx]);
1736 return -1;
1737 }
1738 if (o_tty->link != tty) {
1739 tty_debug(tty, "bad link = %p\n", o_tty->link);
1740 return -1;
1741 }
1742 }
1743#endif
1744 return 0;
1745}
1746
1747/**
1748 * tty_release - vfs callback for close
1749 * @inode: inode of tty
1750 * @filp: file pointer for handle to tty
1751 *
1752 * Called the last time each file handle is closed that references
1753 * this tty. There may however be several such references.
1754 *
1755 * Locking:
1756 * Takes bkl. See tty_release_dev
1757 *
1758 * Even releasing the tty structures is a tricky business.. We have
1759 * to be very careful that the structures are all released at the
1760 * same time, as interrupts might otherwise get the wrong pointers.
1761 *
1762 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1763 * lead to double frees or releasing memory still in use.
1764 */
1765
1766int tty_release(struct inode *inode, struct file *filp)
1767{
1768 struct tty_struct *tty = file_tty(filp);
1769 struct tty_struct *o_tty = NULL;
1770 int do_sleep, final;
1771 int idx;
1772 long timeout = 0;
1773 int once = 1;
1774
1775 if (tty_paranoia_check(tty, inode, __func__))
1776 return 0;
1777
1778 tty_lock(tty);
1779 check_tty_count(tty, __func__);
1780
1781 __tty_fasync(-1, filp, 0);
1782
1783 idx = tty->index;
1784 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1785 tty->driver->subtype == PTY_TYPE_MASTER)
1786 o_tty = tty->link;
1787
1788 if (tty_release_checks(tty, idx)) {
1789 tty_unlock(tty);
1790 return 0;
1791 }
1792
1793 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1794
1795 if (tty->ops->close)
1796 tty->ops->close(tty, filp);
1797
1798 /* If tty is pty master, lock the slave pty (stable lock order) */
1799 tty_lock_slave(o_tty);
1800
1801 /*
1802 * Sanity check: if tty->count is going to zero, there shouldn't be
1803 * any waiters on tty->read_wait or tty->write_wait. We test the
1804 * wait queues and kick everyone out _before_ actually starting to
1805 * close. This ensures that we won't block while releasing the tty
1806 * structure.
1807 *
1808 * The test for the o_tty closing is necessary, since the master and
1809 * slave sides may close in any order. If the slave side closes out
1810 * first, its count will be one, since the master side holds an open.
1811 * Thus this test wouldn't be triggered at the time the slave closed,
1812 * so we do it now.
1813 */
1814 while (1) {
1815 do_sleep = 0;
1816
1817 if (tty->count <= 1) {
1818 if (waitqueue_active(&tty->read_wait)) {
1819 wake_up_poll(&tty->read_wait, POLLIN);
1820 do_sleep++;
1821 }
1822 if (waitqueue_active(&tty->write_wait)) {
1823 wake_up_poll(&tty->write_wait, POLLOUT);
1824 do_sleep++;
1825 }
1826 }
1827 if (o_tty && o_tty->count <= 1) {
1828 if (waitqueue_active(&o_tty->read_wait)) {
1829 wake_up_poll(&o_tty->read_wait, POLLIN);
1830 do_sleep++;
1831 }
1832 if (waitqueue_active(&o_tty->write_wait)) {
1833 wake_up_poll(&o_tty->write_wait, POLLOUT);
1834 do_sleep++;
1835 }
1836 }
1837 if (!do_sleep)
1838 break;
1839
1840 if (once) {
1841 once = 0;
1842 tty_warn(tty, "read/write wait queue active!\n");
1843 }
1844 schedule_timeout_killable(timeout);
1845 if (timeout < 120 * HZ)
1846 timeout = 2 * timeout + 1;
1847 else
1848 timeout = MAX_SCHEDULE_TIMEOUT;
1849 }
1850
1851 if (o_tty) {
1852 if (--o_tty->count < 0) {
1853 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1854 o_tty->count = 0;
1855 }
1856 }
1857 if (--tty->count < 0) {
1858 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1859 tty->count = 0;
1860 }
1861
1862 /*
1863 * We've decremented tty->count, so we need to remove this file
1864 * descriptor off the tty->tty_files list; this serves two
1865 * purposes:
1866 * - check_tty_count sees the correct number of file descriptors
1867 * associated with this tty.
1868 * - do_tty_hangup no longer sees this file descriptor as
1869 * something that needs to be handled for hangups.
1870 */
1871 tty_del_file(filp);
1872
1873 /*
1874 * Perform some housekeeping before deciding whether to return.
1875 *
1876 * If _either_ side is closing, make sure there aren't any
1877 * processes that still think tty or o_tty is their controlling
1878 * tty.
1879 */
1880 if (!tty->count) {
1881 read_lock(&tasklist_lock);
1882 session_clear_tty(tty->session);
1883 if (o_tty)
1884 session_clear_tty(o_tty->session);
1885 read_unlock(&tasklist_lock);
1886 }
1887
1888 /* check whether both sides are closing ... */
1889 final = !tty->count && !(o_tty && o_tty->count);
1890
1891 tty_unlock_slave(o_tty);
1892 tty_unlock(tty);
1893
1894 /* At this point, the tty->count == 0 should ensure a dead tty
1895 cannot be re-opened by a racing opener */
1896
1897 if (!final)
1898 return 0;
1899
1900 tty_debug_hangup(tty, "final close\n");
1901 /*
1902 * Ask the line discipline code to release its structures
1903 */
1904 tty_ldisc_release(tty);
1905
1906 /* Wait for pending work before tty destruction commmences */
1907 tty_flush_works(tty);
1908
1909 tty_debug_hangup(tty, "freeing structure\n");
1910 /*
1911 * The release_tty function takes care of the details of clearing
1912 * the slots and preserving the termios structure. The tty_unlock_pair
1913 * should be safe as we keep a kref while the tty is locked (so the
1914 * unlock never unlocks a freed tty).
1915 */
1916 mutex_lock(&tty_mutex);
1917 release_tty(tty, idx);
1918 mutex_unlock(&tty_mutex);
1919
1920 return 0;
1921}
1922
1923/**
1924 * tty_open_current_tty - get locked tty of current task
1925 * @device: device number
1926 * @filp: file pointer to tty
1927 * @return: locked tty of the current task iff @device is /dev/tty
1928 *
1929 * Performs a re-open of the current task's controlling tty.
1930 *
1931 * We cannot return driver and index like for the other nodes because
1932 * devpts will not work then. It expects inodes to be from devpts FS.
1933 */
1934static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1935{
1936 struct tty_struct *tty;
1937 int retval;
1938
1939 if (device != MKDEV(TTYAUX_MAJOR, 0))
1940 return NULL;
1941
1942 tty = get_current_tty();
1943 if (!tty)
1944 return ERR_PTR(-ENXIO);
1945
1946 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1947 /* noctty = 1; */
1948 tty_lock(tty);
1949 tty_kref_put(tty); /* safe to drop the kref now */
1950
1951 retval = tty_reopen(tty);
1952 if (retval < 0) {
1953 tty_unlock(tty);
1954 tty = ERR_PTR(retval);
1955 }
1956 return tty;
1957}
1958
1959/**
1960 * tty_lookup_driver - lookup a tty driver for a given device file
1961 * @device: device number
1962 * @filp: file pointer to tty
1963 * @index: index for the device in the @return driver
1964 * @return: driver for this inode (with increased refcount)
1965 *
1966 * If @return is not erroneous, the caller is responsible to decrement the
1967 * refcount by tty_driver_kref_put.
1968 *
1969 * Locking: tty_mutex protects get_tty_driver
1970 */
1971static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1972 int *index)
1973{
1974 struct tty_driver *driver;
1975
1976 switch (device) {
1977#ifdef CONFIG_VT
1978 case MKDEV(TTY_MAJOR, 0): {
1979 extern struct tty_driver *console_driver;
1980 driver = tty_driver_kref_get(console_driver);
1981 *index = fg_console;
1982 break;
1983 }
1984#endif
1985 case MKDEV(TTYAUX_MAJOR, 1): {
1986 struct tty_driver *console_driver = console_device(index);
1987 if (console_driver) {
1988 driver = tty_driver_kref_get(console_driver);
1989 if (driver) {
1990 /* Don't let /dev/console block */
1991 filp->f_flags |= O_NONBLOCK;
1992 break;
1993 }
1994 }
1995 return ERR_PTR(-ENODEV);
1996 }
1997 default:
1998 driver = get_tty_driver(device, index);
1999 if (!driver)
2000 return ERR_PTR(-ENODEV);
2001 break;
2002 }
2003 return driver;
2004}
2005
2006/**
2007 * tty_open_by_driver - open a tty device
2008 * @device: dev_t of device to open
2009 * @inode: inode of device file
2010 * @filp: file pointer to tty
2011 *
2012 * Performs the driver lookup, checks for a reopen, or otherwise
2013 * performs the first-time tty initialization.
2014 *
2015 * Returns the locked initialized or re-opened &tty_struct
2016 *
2017 * Claims the global tty_mutex to serialize:
2018 * - concurrent first-time tty initialization
2019 * - concurrent tty driver removal w/ lookup
2020 * - concurrent tty removal from driver table
2021 */
2022static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
2023 struct file *filp)
2024{
2025 struct tty_struct *tty;
2026 struct tty_driver *driver = NULL;
2027 int index = -1;
2028 int retval;
2029
2030 mutex_lock(&tty_mutex);
2031 driver = tty_lookup_driver(device, filp, &index);
2032 if (IS_ERR(driver)) {
2033 mutex_unlock(&tty_mutex);
2034 return ERR_CAST(driver);
2035 }
2036
2037 /* check whether we're reopening an existing tty */
2038 tty = tty_driver_lookup_tty(driver, filp, index);
2039 if (IS_ERR(tty)) {
2040 mutex_unlock(&tty_mutex);
2041 goto out;
2042 }
2043
2044 if (tty) {
2045 mutex_unlock(&tty_mutex);
2046 retval = tty_lock_interruptible(tty);
2047 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2048 if (retval) {
2049 if (retval == -EINTR)
2050 retval = -ERESTARTSYS;
2051 tty = ERR_PTR(retval);
2052 goto out;
2053 }
2054 retval = tty_reopen(tty);
2055 if (retval < 0) {
2056 tty_unlock(tty);
2057 tty = ERR_PTR(retval);
2058 }
2059 } else { /* Returns with the tty_lock held for now */
2060 tty = tty_init_dev(driver, index);
2061 mutex_unlock(&tty_mutex);
2062 }
2063out:
2064 tty_driver_kref_put(driver);
2065 return tty;
2066}
2067
2068/**
2069 * tty_open - open a tty device
2070 * @inode: inode of device file
2071 * @filp: file pointer to tty
2072 *
2073 * tty_open and tty_release keep up the tty count that contains the
2074 * number of opens done on a tty. We cannot use the inode-count, as
2075 * different inodes might point to the same tty.
2076 *
2077 * Open-counting is needed for pty masters, as well as for keeping
2078 * track of serial lines: DTR is dropped when the last close happens.
2079 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2080 *
2081 * The termios state of a pty is reset on first open so that
2082 * settings don't persist across reuse.
2083 *
2084 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2085 * tty->count should protect the rest.
2086 * ->siglock protects ->signal/->sighand
2087 *
2088 * Note: the tty_unlock/lock cases without a ref are only safe due to
2089 * tty_mutex
2090 */
2091
2092static int tty_open(struct inode *inode, struct file *filp)
2093{
2094 struct tty_struct *tty;
2095 int noctty, retval;
2096 dev_t device = inode->i_rdev;
2097 unsigned saved_flags = filp->f_flags;
2098
2099 nonseekable_open(inode, filp);
2100
2101retry_open:
2102 retval = tty_alloc_file(filp);
2103 if (retval)
2104 return -ENOMEM;
2105
2106 tty = tty_open_current_tty(device, filp);
2107 if (!tty)
2108 tty = tty_open_by_driver(device, inode, filp);
2109
2110 if (IS_ERR(tty)) {
2111 tty_free_file(filp);
2112 retval = PTR_ERR(tty);
2113 if (retval != -EAGAIN || signal_pending(current))
2114 return retval;
2115 schedule();
2116 goto retry_open;
2117 }
2118
2119 tty_add_file(tty, filp);
2120
2121 check_tty_count(tty, __func__);
2122 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2123
2124 if (tty->ops->open)
2125 retval = tty->ops->open(tty, filp);
2126 else
2127 retval = -ENODEV;
2128 filp->f_flags = saved_flags;
2129
2130 if (retval) {
2131 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2132
2133 tty_unlock(tty); /* need to call tty_release without BTM */
2134 tty_release(inode, filp);
2135 if (retval != -ERESTARTSYS)
2136 return retval;
2137
2138 if (signal_pending(current))
2139 return retval;
2140
2141 schedule();
2142 /*
2143 * Need to reset f_op in case a hangup happened.
2144 */
2145 if (tty_hung_up_p(filp))
2146 filp->f_op = &tty_fops;
2147 goto retry_open;
2148 }
2149 clear_bit(TTY_HUPPED, &tty->flags);
2150
2151
2152 read_lock(&tasklist_lock);
2153 spin_lock_irq(¤t->sighand->siglock);
2154 noctty = (filp->f_flags & O_NOCTTY) ||
2155 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2156 device == MKDEV(TTYAUX_MAJOR, 1) ||
2157 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2158 tty->driver->subtype == PTY_TYPE_MASTER);
2159
2160 if (!noctty &&
2161 current->signal->leader &&
2162 !current->signal->tty &&
2163 tty->session == NULL) {
2164 /*
2165 * Don't let a process that only has write access to the tty
2166 * obtain the privileges associated with having a tty as
2167 * controlling terminal (being able to reopen it with full
2168 * access through /dev/tty, being able to perform pushback).
2169 * Many distributions set the group of all ttys to "tty" and
2170 * grant write-only access to all terminals for setgid tty
2171 * binaries, which should not imply full privileges on all ttys.
2172 *
2173 * This could theoretically break old code that performs open()
2174 * on a write-only file descriptor. In that case, it might be
2175 * necessary to also permit this if
2176 * inode_permission(inode, MAY_READ) == 0.
2177 */
2178 if (filp->f_mode & FMODE_READ)
2179 __proc_set_tty(tty);
2180 }
2181 spin_unlock_irq(¤t->sighand->siglock);
2182 read_unlock(&tasklist_lock);
2183 tty_unlock(tty);
2184 return 0;
2185}
2186
2187
2188
2189/**
2190 * tty_poll - check tty status
2191 * @filp: file being polled
2192 * @wait: poll wait structures to update
2193 *
2194 * Call the line discipline polling method to obtain the poll
2195 * status of the device.
2196 *
2197 * Locking: locks called line discipline but ldisc poll method
2198 * may be re-entered freely by other callers.
2199 */
2200
2201static unsigned int tty_poll(struct file *filp, poll_table *wait)
2202{
2203 struct tty_struct *tty = file_tty(filp);
2204 struct tty_ldisc *ld;
2205 int ret = 0;
2206
2207 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2208 return 0;
2209
2210 ld = tty_ldisc_ref_wait(tty);
2211 if (!ld)
2212 return hung_up_tty_poll(filp, wait);
2213 if (ld->ops->poll)
2214 ret = ld->ops->poll(tty, filp, wait);
2215 tty_ldisc_deref(ld);
2216 return ret;
2217}
2218
2219static int __tty_fasync(int fd, struct file *filp, int on)
2220{
2221 struct tty_struct *tty = file_tty(filp);
2222 unsigned long flags;
2223 int retval = 0;
2224
2225 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2226 goto out;
2227
2228 retval = fasync_helper(fd, filp, on, &tty->fasync);
2229 if (retval <= 0)
2230 goto out;
2231
2232 if (on) {
2233 enum pid_type type;
2234 struct pid *pid;
2235
2236 spin_lock_irqsave(&tty->ctrl_lock, flags);
2237 if (tty->pgrp) {
2238 pid = tty->pgrp;
2239 type = PIDTYPE_PGID;
2240 } else {
2241 pid = task_pid(current);
2242 type = PIDTYPE_PID;
2243 }
2244 get_pid(pid);
2245 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2246 __f_setown(filp, pid, type, 0);
2247 put_pid(pid);
2248 retval = 0;
2249 }
2250out:
2251 return retval;
2252}
2253
2254static int tty_fasync(int fd, struct file *filp, int on)
2255{
2256 struct tty_struct *tty = file_tty(filp);
2257 int retval = -ENOTTY;
2258
2259 tty_lock(tty);
2260 if (!tty_hung_up_p(filp))
2261 retval = __tty_fasync(fd, filp, on);
2262 tty_unlock(tty);
2263
2264 return retval;
2265}
2266
2267/**
2268 * tiocsti - fake input character
2269 * @tty: tty to fake input into
2270 * @p: pointer to character
2271 *
2272 * Fake input to a tty device. Does the necessary locking and
2273 * input management.
2274 *
2275 * FIXME: does not honour flow control ??
2276 *
2277 * Locking:
2278 * Called functions take tty_ldiscs_lock
2279 * current->signal->tty check is safe without locks
2280 *
2281 * FIXME: may race normal receive processing
2282 */
2283
2284static int tiocsti(struct tty_struct *tty, char __user *p)
2285{
2286 char ch, mbz = 0;
2287 struct tty_ldisc *ld;
2288
2289 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2290 return -EPERM;
2291 if (get_user(ch, p))
2292 return -EFAULT;
2293 tty_audit_tiocsti(tty, ch);
2294 ld = tty_ldisc_ref_wait(tty);
2295 if (!ld)
2296 return -EIO;
2297 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2298 tty_ldisc_deref(ld);
2299 return 0;
2300}
2301
2302/**
2303 * tiocgwinsz - implement window query ioctl
2304 * @tty; tty
2305 * @arg: user buffer for result
2306 *
2307 * Copies the kernel idea of the window size into the user buffer.
2308 *
2309 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2310 * is consistent.
2311 */
2312
2313static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2314{
2315 int err;
2316
2317 mutex_lock(&tty->winsize_mutex);
2318 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2319 mutex_unlock(&tty->winsize_mutex);
2320
2321 return err ? -EFAULT: 0;
2322}
2323
2324/**
2325 * tty_do_resize - resize event
2326 * @tty: tty being resized
2327 * @rows: rows (character)
2328 * @cols: cols (character)
2329 *
2330 * Update the termios variables and send the necessary signals to
2331 * peform a terminal resize correctly
2332 */
2333
2334int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2335{
2336 struct pid *pgrp;
2337
2338 /* Lock the tty */
2339 mutex_lock(&tty->winsize_mutex);
2340 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2341 goto done;
2342
2343 /* Signal the foreground process group */
2344 pgrp = tty_get_pgrp(tty);
2345 if (pgrp)
2346 kill_pgrp(pgrp, SIGWINCH, 1);
2347 put_pid(pgrp);
2348
2349 tty->winsize = *ws;
2350done:
2351 mutex_unlock(&tty->winsize_mutex);
2352 return 0;
2353}
2354EXPORT_SYMBOL(tty_do_resize);
2355
2356/**
2357 * tiocswinsz - implement window size set ioctl
2358 * @tty; tty side of tty
2359 * @arg: user buffer for result
2360 *
2361 * Copies the user idea of the window size to the kernel. Traditionally
2362 * this is just advisory information but for the Linux console it
2363 * actually has driver level meaning and triggers a VC resize.
2364 *
2365 * Locking:
2366 * Driver dependent. The default do_resize method takes the
2367 * tty termios mutex and ctrl_lock. The console takes its own lock
2368 * then calls into the default method.
2369 */
2370
2371static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2372{
2373 struct winsize tmp_ws;
2374 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2375 return -EFAULT;
2376
2377 if (tty->ops->resize)
2378 return tty->ops->resize(tty, &tmp_ws);
2379 else
2380 return tty_do_resize(tty, &tmp_ws);
2381}
2382
2383/**
2384 * tioccons - allow admin to move logical console
2385 * @file: the file to become console
2386 *
2387 * Allow the administrator to move the redirected console device
2388 *
2389 * Locking: uses redirect_lock to guard the redirect information
2390 */
2391
2392static int tioccons(struct file *file)
2393{
2394 if (!capable(CAP_SYS_ADMIN))
2395 return -EPERM;
2396 if (file->f_op->write == redirected_tty_write) {
2397 struct file *f;
2398 spin_lock(&redirect_lock);
2399 f = redirect;
2400 redirect = NULL;
2401 spin_unlock(&redirect_lock);
2402 if (f)
2403 fput(f);
2404 return 0;
2405 }
2406 spin_lock(&redirect_lock);
2407 if (redirect) {
2408 spin_unlock(&redirect_lock);
2409 return -EBUSY;
2410 }
2411 redirect = get_file(file);
2412 spin_unlock(&redirect_lock);
2413 return 0;
2414}
2415
2416/**
2417 * fionbio - non blocking ioctl
2418 * @file: file to set blocking value
2419 * @p: user parameter
2420 *
2421 * Historical tty interfaces had a blocking control ioctl before
2422 * the generic functionality existed. This piece of history is preserved
2423 * in the expected tty API of posix OS's.
2424 *
2425 * Locking: none, the open file handle ensures it won't go away.
2426 */
2427
2428static int fionbio(struct file *file, int __user *p)
2429{
2430 int nonblock;
2431
2432 if (get_user(nonblock, p))
2433 return -EFAULT;
2434
2435 spin_lock(&file->f_lock);
2436 if (nonblock)
2437 file->f_flags |= O_NONBLOCK;
2438 else
2439 file->f_flags &= ~O_NONBLOCK;
2440 spin_unlock(&file->f_lock);
2441 return 0;
2442}
2443
2444/**
2445 * tiocsctty - set controlling tty
2446 * @tty: tty structure
2447 * @arg: user argument
2448 *
2449 * This ioctl is used to manage job control. It permits a session
2450 * leader to set this tty as the controlling tty for the session.
2451 *
2452 * Locking:
2453 * Takes tty_lock() to serialize proc_set_tty() for this tty
2454 * Takes tasklist_lock internally to walk sessions
2455 * Takes ->siglock() when updating signal->tty
2456 */
2457
2458static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2459{
2460 int ret = 0;
2461
2462 tty_lock(tty);
2463 read_lock(&tasklist_lock);
2464
2465 if (current->signal->leader && (task_session(current) == tty->session))
2466 goto unlock;
2467
2468 /*
2469 * The process must be a session leader and
2470 * not have a controlling tty already.
2471 */
2472 if (!current->signal->leader || current->signal->tty) {
2473 ret = -EPERM;
2474 goto unlock;
2475 }
2476
2477 if (tty->session) {
2478 /*
2479 * This tty is already the controlling
2480 * tty for another session group!
2481 */
2482 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2483 /*
2484 * Steal it away
2485 */
2486 session_clear_tty(tty->session);
2487 } else {
2488 ret = -EPERM;
2489 goto unlock;
2490 }
2491 }
2492
2493 /* See the comment in tty_open(). */
2494 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2495 ret = -EPERM;
2496 goto unlock;
2497 }
2498
2499 proc_set_tty(tty);
2500unlock:
2501 read_unlock(&tasklist_lock);
2502 tty_unlock(tty);
2503 return ret;
2504}
2505
2506/**
2507 * tty_get_pgrp - return a ref counted pgrp pid
2508 * @tty: tty to read
2509 *
2510 * Returns a refcounted instance of the pid struct for the process
2511 * group controlling the tty.
2512 */
2513
2514struct pid *tty_get_pgrp(struct tty_struct *tty)
2515{
2516 unsigned long flags;
2517 struct pid *pgrp;
2518
2519 spin_lock_irqsave(&tty->ctrl_lock, flags);
2520 pgrp = get_pid(tty->pgrp);
2521 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2522
2523 return pgrp;
2524}
2525EXPORT_SYMBOL_GPL(tty_get_pgrp);
2526
2527/*
2528 * This checks not only the pgrp, but falls back on the pid if no
2529 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2530 * without this...
2531 *
2532 * The caller must hold rcu lock or the tasklist lock.
2533 */
2534static struct pid *session_of_pgrp(struct pid *pgrp)
2535{
2536 struct task_struct *p;
2537 struct pid *sid = NULL;
2538
2539 p = pid_task(pgrp, PIDTYPE_PGID);
2540 if (p == NULL)
2541 p = pid_task(pgrp, PIDTYPE_PID);
2542 if (p != NULL)
2543 sid = task_session(p);
2544
2545 return sid;
2546}
2547
2548/**
2549 * tiocgpgrp - get process group
2550 * @tty: tty passed by user
2551 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2552 * @p: returned pid
2553 *
2554 * Obtain the process group of the tty. If there is no process group
2555 * return an error.
2556 *
2557 * Locking: none. Reference to current->signal->tty is safe.
2558 */
2559
2560static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2561{
2562 struct pid *pid;
2563 int ret;
2564 /*
2565 * (tty == real_tty) is a cheap way of
2566 * testing if the tty is NOT a master pty.
2567 */
2568 if (tty == real_tty && current->signal->tty != real_tty)
2569 return -ENOTTY;
2570 pid = tty_get_pgrp(real_tty);
2571 ret = put_user(pid_vnr(pid), p);
2572 put_pid(pid);
2573 return ret;
2574}
2575
2576/**
2577 * tiocspgrp - attempt to set process group
2578 * @tty: tty passed by user
2579 * @real_tty: tty side device matching tty passed by user
2580 * @p: pid pointer
2581 *
2582 * Set the process group of the tty to the session passed. Only
2583 * permitted where the tty session is our session.
2584 *
2585 * Locking: RCU, ctrl lock
2586 */
2587
2588static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2589{
2590 struct pid *pgrp;
2591 pid_t pgrp_nr;
2592 int retval = tty_check_change(real_tty);
2593
2594 if (retval == -EIO)
2595 return -ENOTTY;
2596 if (retval)
2597 return retval;
2598 if (!current->signal->tty ||
2599 (current->signal->tty != real_tty) ||
2600 (real_tty->session != task_session(current)))
2601 return -ENOTTY;
2602 if (get_user(pgrp_nr, p))
2603 return -EFAULT;
2604 if (pgrp_nr < 0)
2605 return -EINVAL;
2606 rcu_read_lock();
2607 pgrp = find_vpid(pgrp_nr);
2608 retval = -ESRCH;
2609 if (!pgrp)
2610 goto out_unlock;
2611 retval = -EPERM;
2612 if (session_of_pgrp(pgrp) != task_session(current))
2613 goto out_unlock;
2614 retval = 0;
2615 spin_lock_irq(&tty->ctrl_lock);
2616 put_pid(real_tty->pgrp);
2617 real_tty->pgrp = get_pid(pgrp);
2618 spin_unlock_irq(&tty->ctrl_lock);
2619out_unlock:
2620 rcu_read_unlock();
2621 return retval;
2622}
2623
2624/**
2625 * tiocgsid - get session id
2626 * @tty: tty passed by user
2627 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2628 * @p: pointer to returned session id
2629 *
2630 * Obtain the session id of the tty. If there is no session
2631 * return an error.
2632 *
2633 * Locking: none. Reference to current->signal->tty is safe.
2634 */
2635
2636static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2637{
2638 /*
2639 * (tty == real_tty) is a cheap way of
2640 * testing if the tty is NOT a master pty.
2641 */
2642 if (tty == real_tty && current->signal->tty != real_tty)
2643 return -ENOTTY;
2644 if (!real_tty->session)
2645 return -ENOTTY;
2646 return put_user(pid_vnr(real_tty->session), p);
2647}
2648
2649/**
2650 * tiocsetd - set line discipline
2651 * @tty: tty device
2652 * @p: pointer to user data
2653 *
2654 * Set the line discipline according to user request.
2655 *
2656 * Locking: see tty_set_ldisc, this function is just a helper
2657 */
2658
2659static int tiocsetd(struct tty_struct *tty, int __user *p)
2660{
2661 int disc;
2662 int ret;
2663
2664 if (get_user(disc, p))
2665 return -EFAULT;
2666
2667 ret = tty_set_ldisc(tty, disc);
2668
2669 return ret;
2670}
2671
2672/**
2673 * tiocgetd - get line discipline
2674 * @tty: tty device
2675 * @p: pointer to user data
2676 *
2677 * Retrieves the line discipline id directly from the ldisc.
2678 *
2679 * Locking: waits for ldisc reference (in case the line discipline
2680 * is changing or the tty is being hungup)
2681 */
2682
2683static int tiocgetd(struct tty_struct *tty, int __user *p)
2684{
2685 struct tty_ldisc *ld;
2686 int ret;
2687
2688 ld = tty_ldisc_ref_wait(tty);
2689 if (!ld)
2690 return -EIO;
2691 ret = put_user(ld->ops->num, p);
2692 tty_ldisc_deref(ld);
2693 return ret;
2694}
2695
2696/**
2697 * send_break - performed time break
2698 * @tty: device to break on
2699 * @duration: timeout in mS
2700 *
2701 * Perform a timed break on hardware that lacks its own driver level
2702 * timed break functionality.
2703 *
2704 * Locking:
2705 * atomic_write_lock serializes
2706 *
2707 */
2708
2709static int send_break(struct tty_struct *tty, unsigned int duration)
2710{
2711 int retval;
2712
2713 if (tty->ops->break_ctl == NULL)
2714 return 0;
2715
2716 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2717 retval = tty->ops->break_ctl(tty, duration);
2718 else {
2719 /* Do the work ourselves */
2720 if (tty_write_lock(tty, 0) < 0)
2721 return -EINTR;
2722 retval = tty->ops->break_ctl(tty, -1);
2723 if (retval)
2724 goto out;
2725 if (!signal_pending(current))
2726 msleep_interruptible(duration);
2727 retval = tty->ops->break_ctl(tty, 0);
2728out:
2729 tty_write_unlock(tty);
2730 if (signal_pending(current))
2731 retval = -EINTR;
2732 }
2733 return retval;
2734}
2735
2736/**
2737 * tty_tiocmget - get modem status
2738 * @tty: tty device
2739 * @file: user file pointer
2740 * @p: pointer to result
2741 *
2742 * Obtain the modem status bits from the tty driver if the feature
2743 * is supported. Return -EINVAL if it is not available.
2744 *
2745 * Locking: none (up to the driver)
2746 */
2747
2748static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2749{
2750 int retval = -EINVAL;
2751
2752 if (tty->ops->tiocmget) {
2753 retval = tty->ops->tiocmget(tty);
2754
2755 if (retval >= 0)
2756 retval = put_user(retval, p);
2757 }
2758 return retval;
2759}
2760
2761/**
2762 * tty_tiocmset - set modem status
2763 * @tty: tty device
2764 * @cmd: command - clear bits, set bits or set all
2765 * @p: pointer to desired bits
2766 *
2767 * Set the modem status bits from the tty driver if the feature
2768 * is supported. Return -EINVAL if it is not available.
2769 *
2770 * Locking: none (up to the driver)
2771 */
2772
2773static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2774 unsigned __user *p)
2775{
2776 int retval;
2777 unsigned int set, clear, val;
2778
2779 if (tty->ops->tiocmset == NULL)
2780 return -EINVAL;
2781
2782 retval = get_user(val, p);
2783 if (retval)
2784 return retval;
2785 set = clear = 0;
2786 switch (cmd) {
2787 case TIOCMBIS:
2788 set = val;
2789 break;
2790 case TIOCMBIC:
2791 clear = val;
2792 break;
2793 case TIOCMSET:
2794 set = val;
2795 clear = ~val;
2796 break;
2797 }
2798 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2799 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2800 return tty->ops->tiocmset(tty, set, clear);
2801}
2802
2803static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2804{
2805 int retval = -EINVAL;
2806 struct serial_icounter_struct icount;
2807 memset(&icount, 0, sizeof(icount));
2808 if (tty->ops->get_icount)
2809 retval = tty->ops->get_icount(tty, &icount);
2810 if (retval != 0)
2811 return retval;
2812 if (copy_to_user(arg, &icount, sizeof(icount)))
2813 return -EFAULT;
2814 return 0;
2815}
2816
2817static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2818{
2819 static DEFINE_RATELIMIT_STATE(depr_flags,
2820 DEFAULT_RATELIMIT_INTERVAL,
2821 DEFAULT_RATELIMIT_BURST);
2822 char comm[TASK_COMM_LEN];
2823 int flags;
2824
2825 if (get_user(flags, &ss->flags))
2826 return;
2827
2828 flags &= ASYNC_DEPRECATED;
2829
2830 if (flags && __ratelimit(&depr_flags))
2831 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2832 __func__, get_task_comm(comm, current), flags);
2833}
2834
2835/*
2836 * if pty, return the slave side (real_tty)
2837 * otherwise, return self
2838 */
2839static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2840{
2841 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2842 tty->driver->subtype == PTY_TYPE_MASTER)
2843 tty = tty->link;
2844 return tty;
2845}
2846
2847/*
2848 * Split this up, as gcc can choke on it otherwise..
2849 */
2850long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2851{
2852 struct tty_struct *tty = file_tty(file);
2853 struct tty_struct *real_tty;
2854 void __user *p = (void __user *)arg;
2855 int retval;
2856 struct tty_ldisc *ld;
2857
2858 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2859 return -EINVAL;
2860
2861 real_tty = tty_pair_get_tty(tty);
2862
2863 /*
2864 * Factor out some common prep work
2865 */
2866 switch (cmd) {
2867 case TIOCSETD:
2868 case TIOCSBRK:
2869 case TIOCCBRK:
2870 case TCSBRK:
2871 case TCSBRKP:
2872 retval = tty_check_change(tty);
2873 if (retval)
2874 return retval;
2875 if (cmd != TIOCCBRK) {
2876 tty_wait_until_sent(tty, 0);
2877 if (signal_pending(current))
2878 return -EINTR;
2879 }
2880 break;
2881 }
2882
2883 /*
2884 * Now do the stuff.
2885 */
2886 switch (cmd) {
2887 case TIOCSTI:
2888 return tiocsti(tty, p);
2889 case TIOCGWINSZ:
2890 return tiocgwinsz(real_tty, p);
2891 case TIOCSWINSZ:
2892 return tiocswinsz(real_tty, p);
2893 case TIOCCONS:
2894 return real_tty != tty ? -EINVAL : tioccons(file);
2895 case FIONBIO:
2896 return fionbio(file, p);
2897 case TIOCEXCL:
2898 set_bit(TTY_EXCLUSIVE, &tty->flags);
2899 return 0;
2900 case TIOCNXCL:
2901 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2902 return 0;
2903 case TIOCGEXCL:
2904 {
2905 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2906 return put_user(excl, (int __user *)p);
2907 }
2908 case TIOCNOTTY:
2909 if (current->signal->tty != tty)
2910 return -ENOTTY;
2911 no_tty();
2912 return 0;
2913 case TIOCSCTTY:
2914 return tiocsctty(real_tty, file, arg);
2915 case TIOCGPGRP:
2916 return tiocgpgrp(tty, real_tty, p);
2917 case TIOCSPGRP:
2918 return tiocspgrp(tty, real_tty, p);
2919 case TIOCGSID:
2920 return tiocgsid(tty, real_tty, p);
2921 case TIOCGETD:
2922 return tiocgetd(tty, p);
2923 case TIOCSETD:
2924 return tiocsetd(tty, p);
2925 case TIOCVHANGUP:
2926 if (!capable(CAP_SYS_ADMIN))
2927 return -EPERM;
2928 tty_vhangup(tty);
2929 return 0;
2930 case TIOCGDEV:
2931 {
2932 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2933 return put_user(ret, (unsigned int __user *)p);
2934 }
2935 /*
2936 * Break handling
2937 */
2938 case TIOCSBRK: /* Turn break on, unconditionally */
2939 if (tty->ops->break_ctl)
2940 return tty->ops->break_ctl(tty, -1);
2941 return 0;
2942 case TIOCCBRK: /* Turn break off, unconditionally */
2943 if (tty->ops->break_ctl)
2944 return tty->ops->break_ctl(tty, 0);
2945 return 0;
2946 case TCSBRK: /* SVID version: non-zero arg --> no break */
2947 /* non-zero arg means wait for all output data
2948 * to be sent (performed above) but don't send break.
2949 * This is used by the tcdrain() termios function.
2950 */
2951 if (!arg)
2952 return send_break(tty, 250);
2953 return 0;
2954 case TCSBRKP: /* support for POSIX tcsendbreak() */
2955 return send_break(tty, arg ? arg*100 : 250);
2956
2957 case TIOCMGET:
2958 return tty_tiocmget(tty, p);
2959 case TIOCMSET:
2960 case TIOCMBIC:
2961 case TIOCMBIS:
2962 return tty_tiocmset(tty, cmd, p);
2963 case TIOCGICOUNT:
2964 retval = tty_tiocgicount(tty, p);
2965 /* For the moment allow fall through to the old method */
2966 if (retval != -EINVAL)
2967 return retval;
2968 break;
2969 case TCFLSH:
2970 switch (arg) {
2971 case TCIFLUSH:
2972 case TCIOFLUSH:
2973 /* flush tty buffer and allow ldisc to process ioctl */
2974 tty_buffer_flush(tty, NULL);
2975 break;
2976 }
2977 break;
2978 case TIOCSSERIAL:
2979 tty_warn_deprecated_flags(p);
2980 break;
2981 }
2982 if (tty->ops->ioctl) {
2983 retval = tty->ops->ioctl(tty, cmd, arg);
2984 if (retval != -ENOIOCTLCMD)
2985 return retval;
2986 }
2987 ld = tty_ldisc_ref_wait(tty);
2988 if (!ld)
2989 return hung_up_tty_ioctl(file, cmd, arg);
2990 retval = -EINVAL;
2991 if (ld->ops->ioctl) {
2992 retval = ld->ops->ioctl(tty, file, cmd, arg);
2993 if (retval == -ENOIOCTLCMD)
2994 retval = -ENOTTY;
2995 }
2996 tty_ldisc_deref(ld);
2997 return retval;
2998}
2999
3000#ifdef CONFIG_COMPAT
3001static long tty_compat_ioctl(struct file *file, unsigned int cmd,
3002 unsigned long arg)
3003{
3004 struct tty_struct *tty = file_tty(file);
3005 struct tty_ldisc *ld;
3006 int retval = -ENOIOCTLCMD;
3007
3008 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3009 return -EINVAL;
3010
3011 if (tty->ops->compat_ioctl) {
3012 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3013 if (retval != -ENOIOCTLCMD)
3014 return retval;
3015 }
3016
3017 ld = tty_ldisc_ref_wait(tty);
3018 if (!ld)
3019 return hung_up_tty_compat_ioctl(file, cmd, arg);
3020 if (ld->ops->compat_ioctl)
3021 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3022 else
3023 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3024 tty_ldisc_deref(ld);
3025
3026 return retval;
3027}
3028#endif
3029
3030static int this_tty(const void *t, struct file *file, unsigned fd)
3031{
3032 if (likely(file->f_op->read != tty_read))
3033 return 0;
3034 return file_tty(file) != t ? 0 : fd + 1;
3035}
3036
3037/*
3038 * This implements the "Secure Attention Key" --- the idea is to
3039 * prevent trojan horses by killing all processes associated with this
3040 * tty when the user hits the "Secure Attention Key". Required for
3041 * super-paranoid applications --- see the Orange Book for more details.
3042 *
3043 * This code could be nicer; ideally it should send a HUP, wait a few
3044 * seconds, then send a INT, and then a KILL signal. But you then
3045 * have to coordinate with the init process, since all processes associated
3046 * with the current tty must be dead before the new getty is allowed
3047 * to spawn.
3048 *
3049 * Now, if it would be correct ;-/ The current code has a nasty hole -
3050 * it doesn't catch files in flight. We may send the descriptor to ourselves
3051 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3052 *
3053 * Nasty bug: do_SAK is being called in interrupt context. This can
3054 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3055 */
3056void __do_SAK(struct tty_struct *tty)
3057{
3058#ifdef TTY_SOFT_SAK
3059 tty_hangup(tty);
3060#else
3061 struct task_struct *g, *p;
3062 struct pid *session;
3063 int i;
3064
3065 if (!tty)
3066 return;
3067 session = tty->session;
3068
3069 tty_ldisc_flush(tty);
3070
3071 tty_driver_flush_buffer(tty);
3072
3073 read_lock(&tasklist_lock);
3074 /* Kill the entire session */
3075 do_each_pid_task(session, PIDTYPE_SID, p) {
3076 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3077 task_pid_nr(p), p->comm);
3078 send_sig(SIGKILL, p, 1);
3079 } while_each_pid_task(session, PIDTYPE_SID, p);
3080
3081 /* Now kill any processes that happen to have the tty open */
3082 do_each_thread(g, p) {
3083 if (p->signal->tty == tty) {
3084 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3085 task_pid_nr(p), p->comm);
3086 send_sig(SIGKILL, p, 1);
3087 continue;
3088 }
3089 task_lock(p);
3090 i = iterate_fd(p->files, 0, this_tty, tty);
3091 if (i != 0) {
3092 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3093 task_pid_nr(p), p->comm, i - 1);
3094 force_sig(SIGKILL, p);
3095 }
3096 task_unlock(p);
3097 } while_each_thread(g, p);
3098 read_unlock(&tasklist_lock);
3099#endif
3100}
3101
3102static void do_SAK_work(struct work_struct *work)
3103{
3104 struct tty_struct *tty =
3105 container_of(work, struct tty_struct, SAK_work);
3106 __do_SAK(tty);
3107}
3108
3109/*
3110 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3111 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3112 * the values which we write to it will be identical to the values which it
3113 * already has. --akpm
3114 */
3115void do_SAK(struct tty_struct *tty)
3116{
3117 if (!tty)
3118 return;
3119 schedule_work(&tty->SAK_work);
3120}
3121
3122EXPORT_SYMBOL(do_SAK);
3123
3124static int dev_match_devt(struct device *dev, const void *data)
3125{
3126 const dev_t *devt = data;
3127 return dev->devt == *devt;
3128}
3129
3130/* Must put_device() after it's unused! */
3131static struct device *tty_get_device(struct tty_struct *tty)
3132{
3133 dev_t devt = tty_devnum(tty);
3134 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3135}
3136
3137
3138/**
3139 * alloc_tty_struct
3140 *
3141 * This subroutine allocates and initializes a tty structure.
3142 *
3143 * Locking: none - tty in question is not exposed at this point
3144 */
3145
3146struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3147{
3148 struct tty_struct *tty;
3149
3150 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3151 if (!tty)
3152 return NULL;
3153
3154 kref_init(&tty->kref);
3155 tty->magic = TTY_MAGIC;
3156 tty_ldisc_init(tty);
3157 tty->session = NULL;
3158 tty->pgrp = NULL;
3159 mutex_init(&tty->legacy_mutex);
3160 mutex_init(&tty->throttle_mutex);
3161 init_rwsem(&tty->termios_rwsem);
3162 mutex_init(&tty->winsize_mutex);
3163 init_ldsem(&tty->ldisc_sem);
3164 init_waitqueue_head(&tty->write_wait);
3165 init_waitqueue_head(&tty->read_wait);
3166 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3167 mutex_init(&tty->atomic_write_lock);
3168 spin_lock_init(&tty->ctrl_lock);
3169 spin_lock_init(&tty->flow_lock);
3170 spin_lock_init(&tty->files_lock);
3171 INIT_LIST_HEAD(&tty->tty_files);
3172 INIT_WORK(&tty->SAK_work, do_SAK_work);
3173
3174 tty->driver = driver;
3175 tty->ops = driver->ops;
3176 tty->index = idx;
3177 tty_line_name(driver, idx, tty->name);
3178 tty->dev = tty_get_device(tty);
3179
3180 return tty;
3181}
3182
3183/**
3184 * tty_put_char - write one character to a tty
3185 * @tty: tty
3186 * @ch: character
3187 *
3188 * Write one byte to the tty using the provided put_char method
3189 * if present. Returns the number of characters successfully output.
3190 *
3191 * Note: the specific put_char operation in the driver layer may go
3192 * away soon. Don't call it directly, use this method
3193 */
3194
3195int tty_put_char(struct tty_struct *tty, unsigned char ch)
3196{
3197 if (tty->ops->put_char)
3198 return tty->ops->put_char(tty, ch);
3199 return tty->ops->write(tty, &ch, 1);
3200}
3201EXPORT_SYMBOL_GPL(tty_put_char);
3202
3203struct class *tty_class;
3204
3205static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3206 unsigned int index, unsigned int count)
3207{
3208 int err;
3209
3210 /* init here, since reused cdevs cause crashes */
3211 driver->cdevs[index] = cdev_alloc();
3212 if (!driver->cdevs[index])
3213 return -ENOMEM;
3214 driver->cdevs[index]->ops = &tty_fops;
3215 driver->cdevs[index]->owner = driver->owner;
3216 err = cdev_add(driver->cdevs[index], dev, count);
3217 if (err)
3218 kobject_put(&driver->cdevs[index]->kobj);
3219 return err;
3220}
3221
3222/**
3223 * tty_register_device - register a tty device
3224 * @driver: the tty driver that describes the tty device
3225 * @index: the index in the tty driver for this tty device
3226 * @device: a struct device that is associated with this tty device.
3227 * This field is optional, if there is no known struct device
3228 * for this tty device it can be set to NULL safely.
3229 *
3230 * Returns a pointer to the struct device for this tty device
3231 * (or ERR_PTR(-EFOO) on error).
3232 *
3233 * This call is required to be made to register an individual tty device
3234 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3235 * that bit is not set, this function should not be called by a tty
3236 * driver.
3237 *
3238 * Locking: ??
3239 */
3240
3241struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3242 struct device *device)
3243{
3244 return tty_register_device_attr(driver, index, device, NULL, NULL);
3245}
3246EXPORT_SYMBOL(tty_register_device);
3247
3248static void tty_device_create_release(struct device *dev)
3249{
3250 dev_dbg(dev, "releasing...\n");
3251 kfree(dev);
3252}
3253
3254/**
3255 * tty_register_device_attr - register a tty device
3256 * @driver: the tty driver that describes the tty device
3257 * @index: the index in the tty driver for this tty device
3258 * @device: a struct device that is associated with this tty device.
3259 * This field is optional, if there is no known struct device
3260 * for this tty device it can be set to NULL safely.
3261 * @drvdata: Driver data to be set to device.
3262 * @attr_grp: Attribute group to be set on device.
3263 *
3264 * Returns a pointer to the struct device for this tty device
3265 * (or ERR_PTR(-EFOO) on error).
3266 *
3267 * This call is required to be made to register an individual tty device
3268 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3269 * that bit is not set, this function should not be called by a tty
3270 * driver.
3271 *
3272 * Locking: ??
3273 */
3274struct device *tty_register_device_attr(struct tty_driver *driver,
3275 unsigned index, struct device *device,
3276 void *drvdata,
3277 const struct attribute_group **attr_grp)
3278{
3279 char name[64];
3280 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3281 struct device *dev = NULL;
3282 int retval = -ENODEV;
3283 bool cdev = false;
3284
3285 if (index >= driver->num) {
3286 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3287 driver->name, index);
3288 return ERR_PTR(-EINVAL);
3289 }
3290
3291 if (driver->type == TTY_DRIVER_TYPE_PTY)
3292 pty_line_name(driver, index, name);
3293 else
3294 tty_line_name(driver, index, name);
3295
3296 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3297 retval = tty_cdev_add(driver, devt, index, 1);
3298 if (retval)
3299 goto error;
3300 cdev = true;
3301 }
3302
3303 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3304 if (!dev) {
3305 retval = -ENOMEM;
3306 goto error;
3307 }
3308
3309 dev->devt = devt;
3310 dev->class = tty_class;
3311 dev->parent = device;
3312 dev->release = tty_device_create_release;
3313 dev_set_name(dev, "%s", name);
3314 dev->groups = attr_grp;
3315 dev_set_drvdata(dev, drvdata);
3316
3317 retval = device_register(dev);
3318 if (retval)
3319 goto error;
3320
3321 return dev;
3322
3323error:
3324 put_device(dev);
3325 if (cdev) {
3326 cdev_del(driver->cdevs[index]);
3327 driver->cdevs[index] = NULL;
3328 }
3329 return ERR_PTR(retval);
3330}
3331EXPORT_SYMBOL_GPL(tty_register_device_attr);
3332
3333/**
3334 * tty_unregister_device - unregister a tty device
3335 * @driver: the tty driver that describes the tty device
3336 * @index: the index in the tty driver for this tty device
3337 *
3338 * If a tty device is registered with a call to tty_register_device() then
3339 * this function must be called when the tty device is gone.
3340 *
3341 * Locking: ??
3342 */
3343
3344void tty_unregister_device(struct tty_driver *driver, unsigned index)
3345{
3346 device_destroy(tty_class,
3347 MKDEV(driver->major, driver->minor_start) + index);
3348 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3349 cdev_del(driver->cdevs[index]);
3350 driver->cdevs[index] = NULL;
3351 }
3352}
3353EXPORT_SYMBOL(tty_unregister_device);
3354
3355/**
3356 * __tty_alloc_driver -- allocate tty driver
3357 * @lines: count of lines this driver can handle at most
3358 * @owner: module which is repsonsible for this driver
3359 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3360 *
3361 * This should not be called directly, some of the provided macros should be
3362 * used instead. Use IS_ERR and friends on @retval.
3363 */
3364struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3365 unsigned long flags)
3366{
3367 struct tty_driver *driver;
3368 unsigned int cdevs = 1;
3369 int err;
3370
3371 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3372 return ERR_PTR(-EINVAL);
3373
3374 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3375 if (!driver)
3376 return ERR_PTR(-ENOMEM);
3377
3378 kref_init(&driver->kref);
3379 driver->magic = TTY_DRIVER_MAGIC;
3380 driver->num = lines;
3381 driver->owner = owner;
3382 driver->flags = flags;
3383
3384 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3385 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3386 GFP_KERNEL);
3387 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3388 GFP_KERNEL);
3389 if (!driver->ttys || !driver->termios) {
3390 err = -ENOMEM;
3391 goto err_free_all;
3392 }
3393 }
3394
3395 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3396 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3397 GFP_KERNEL);
3398 if (!driver->ports) {
3399 err = -ENOMEM;
3400 goto err_free_all;
3401 }
3402 cdevs = lines;
3403 }
3404
3405 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3406 if (!driver->cdevs) {
3407 err = -ENOMEM;
3408 goto err_free_all;
3409 }
3410
3411 return driver;
3412err_free_all:
3413 kfree(driver->ports);
3414 kfree(driver->ttys);
3415 kfree(driver->termios);
3416 kfree(driver->cdevs);
3417 kfree(driver);
3418 return ERR_PTR(err);
3419}
3420EXPORT_SYMBOL(__tty_alloc_driver);
3421
3422static void destruct_tty_driver(struct kref *kref)
3423{
3424 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3425 int i;
3426 struct ktermios *tp;
3427
3428 if (driver->flags & TTY_DRIVER_INSTALLED) {
3429 /*
3430 * Free the termios and termios_locked structures because
3431 * we don't want to get memory leaks when modular tty
3432 * drivers are removed from the kernel.
3433 */
3434 for (i = 0; i < driver->num; i++) {
3435 tp = driver->termios[i];
3436 if (tp) {
3437 driver->termios[i] = NULL;
3438 kfree(tp);
3439 }
3440 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3441 tty_unregister_device(driver, i);
3442 }
3443 proc_tty_unregister_driver(driver);
3444 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3445 cdev_del(driver->cdevs[0]);
3446 }
3447 kfree(driver->cdevs);
3448 kfree(driver->ports);
3449 kfree(driver->termios);
3450 kfree(driver->ttys);
3451 kfree(driver);
3452}
3453
3454void tty_driver_kref_put(struct tty_driver *driver)
3455{
3456 kref_put(&driver->kref, destruct_tty_driver);
3457}
3458EXPORT_SYMBOL(tty_driver_kref_put);
3459
3460void tty_set_operations(struct tty_driver *driver,
3461 const struct tty_operations *op)
3462{
3463 driver->ops = op;
3464};
3465EXPORT_SYMBOL(tty_set_operations);
3466
3467void put_tty_driver(struct tty_driver *d)
3468{
3469 tty_driver_kref_put(d);
3470}
3471EXPORT_SYMBOL(put_tty_driver);
3472
3473/*
3474 * Called by a tty driver to register itself.
3475 */
3476int tty_register_driver(struct tty_driver *driver)
3477{
3478 int error;
3479 int i;
3480 dev_t dev;
3481 struct device *d;
3482
3483 if (!driver->major) {
3484 error = alloc_chrdev_region(&dev, driver->minor_start,
3485 driver->num, driver->name);
3486 if (!error) {
3487 driver->major = MAJOR(dev);
3488 driver->minor_start = MINOR(dev);
3489 }
3490 } else {
3491 dev = MKDEV(driver->major, driver->minor_start);
3492 error = register_chrdev_region(dev, driver->num, driver->name);
3493 }
3494 if (error < 0)
3495 goto err;
3496
3497 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3498 error = tty_cdev_add(driver, dev, 0, driver->num);
3499 if (error)
3500 goto err_unreg_char;
3501 }
3502
3503 mutex_lock(&tty_mutex);
3504 list_add(&driver->tty_drivers, &tty_drivers);
3505 mutex_unlock(&tty_mutex);
3506
3507 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3508 for (i = 0; i < driver->num; i++) {
3509 d = tty_register_device(driver, i, NULL);
3510 if (IS_ERR(d)) {
3511 error = PTR_ERR(d);
3512 goto err_unreg_devs;
3513 }
3514 }
3515 }
3516 proc_tty_register_driver(driver);
3517 driver->flags |= TTY_DRIVER_INSTALLED;
3518 return 0;
3519
3520err_unreg_devs:
3521 for (i--; i >= 0; i--)
3522 tty_unregister_device(driver, i);
3523
3524 mutex_lock(&tty_mutex);
3525 list_del(&driver->tty_drivers);
3526 mutex_unlock(&tty_mutex);
3527
3528err_unreg_char:
3529 unregister_chrdev_region(dev, driver->num);
3530err:
3531 return error;
3532}
3533EXPORT_SYMBOL(tty_register_driver);
3534
3535/*
3536 * Called by a tty driver to unregister itself.
3537 */
3538int tty_unregister_driver(struct tty_driver *driver)
3539{
3540#if 0
3541 /* FIXME */
3542 if (driver->refcount)
3543 return -EBUSY;
3544#endif
3545 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3546 driver->num);
3547 mutex_lock(&tty_mutex);
3548 list_del(&driver->tty_drivers);
3549 mutex_unlock(&tty_mutex);
3550 return 0;
3551}
3552
3553EXPORT_SYMBOL(tty_unregister_driver);
3554
3555dev_t tty_devnum(struct tty_struct *tty)
3556{
3557 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3558}
3559EXPORT_SYMBOL(tty_devnum);
3560
3561void tty_default_fops(struct file_operations *fops)
3562{
3563 *fops = tty_fops;
3564}
3565
3566/*
3567 * Initialize the console device. This is called *early*, so
3568 * we can't necessarily depend on lots of kernel help here.
3569 * Just do some early initializations, and do the complex setup
3570 * later.
3571 */
3572void __init console_init(void)
3573{
3574 initcall_t *call;
3575
3576 /* Setup the default TTY line discipline. */
3577 n_tty_init();
3578
3579 /*
3580 * set up the console device so that later boot sequences can
3581 * inform about problems etc..
3582 */
3583 call = __con_initcall_start;
3584 while (call < __con_initcall_end) {
3585 (*call)();
3586 call++;
3587 }
3588}
3589
3590static char *tty_devnode(struct device *dev, umode_t *mode)
3591{
3592 if (!mode)
3593 return NULL;
3594 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3595 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3596 *mode = 0666;
3597 return NULL;
3598}
3599
3600static int __init tty_class_init(void)
3601{
3602 tty_class = class_create(THIS_MODULE, "tty");
3603 if (IS_ERR(tty_class))
3604 return PTR_ERR(tty_class);
3605 tty_class->devnode = tty_devnode;
3606 return 0;
3607}
3608
3609postcore_initcall(tty_class_init);
3610
3611/* 3/2004 jmc: why do these devices exist? */
3612static struct cdev tty_cdev, console_cdev;
3613
3614static ssize_t show_cons_active(struct device *dev,
3615 struct device_attribute *attr, char *buf)
3616{
3617 struct console *cs[16];
3618 int i = 0;
3619 struct console *c;
3620 ssize_t count = 0;
3621
3622 console_lock();
3623 for_each_console(c) {
3624 if (!c->device)
3625 continue;
3626 if (!c->write)
3627 continue;
3628 if ((c->flags & CON_ENABLED) == 0)
3629 continue;
3630 cs[i++] = c;
3631 if (i >= ARRAY_SIZE(cs))
3632 break;
3633 }
3634 while (i--) {
3635 int index = cs[i]->index;
3636 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3637
3638 /* don't resolve tty0 as some programs depend on it */
3639 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3640 count += tty_line_name(drv, index, buf + count);
3641 else
3642 count += sprintf(buf + count, "%s%d",
3643 cs[i]->name, cs[i]->index);
3644
3645 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3646 }
3647 console_unlock();
3648
3649 return count;
3650}
3651static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3652
3653static struct attribute *cons_dev_attrs[] = {
3654 &dev_attr_active.attr,
3655 NULL
3656};
3657
3658ATTRIBUTE_GROUPS(cons_dev);
3659
3660static struct device *consdev;
3661
3662void console_sysfs_notify(void)
3663{
3664 if (consdev)
3665 sysfs_notify(&consdev->kobj, NULL, "active");
3666}
3667
3668/*
3669 * Ok, now we can initialize the rest of the tty devices and can count
3670 * on memory allocations, interrupts etc..
3671 */
3672int __init tty_init(void)
3673{
3674 cdev_init(&tty_cdev, &tty_fops);
3675 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3676 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3677 panic("Couldn't register /dev/tty driver\n");
3678 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3679
3680 cdev_init(&console_cdev, &console_fops);
3681 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3682 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3683 panic("Couldn't register /dev/console driver\n");
3684 consdev = device_create_with_groups(tty_class, NULL,
3685 MKDEV(TTYAUX_MAJOR, 1), NULL,
3686 cons_dev_groups, "console");
3687 if (IS_ERR(consdev))
3688 consdev = NULL;
3689
3690#ifdef CONFIG_VT
3691 vty_init(&console_fops);
3692#endif
3693 return 0;
3694}
3695