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