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1/*
2 * Copyright (C) 1991, 1992 Linus Torvalds
3 */
4
5/*
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
8 *
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
10 *
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
16 *
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
21 *
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
25 *
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
28 * -- TYT, 1/31/92
29 *
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
33 *
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
36 *
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
39 *
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
42 *
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
45 *
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
49 *
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
52 *
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
55 *
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
58 *
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
61 *
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
65 */
66
67#include <linux/types.h>
68#include <linux/major.h>
69#include <linux/errno.h>
70#include <linux/signal.h>
71#include <linux/fcntl.h>
72#include <linux/sched.h>
73#include <linux/interrupt.h>
74#include <linux/tty.h>
75#include <linux/tty_driver.h>
76#include <linux/tty_flip.h>
77#include <linux/devpts_fs.h>
78#include <linux/file.h>
79#include <linux/fdtable.h>
80#include <linux/console.h>
81#include <linux/timer.h>
82#include <linux/ctype.h>
83#include <linux/kd.h>
84#include <linux/mm.h>
85#include <linux/string.h>
86#include <linux/slab.h>
87#include <linux/poll.h>
88#include <linux/proc_fs.h>
89#include <linux/init.h>
90#include <linux/module.h>
91#include <linux/device.h>
92#include <linux/wait.h>
93#include <linux/bitops.h>
94#include <linux/delay.h>
95#include <linux/seq_file.h>
96#include <linux/serial.h>
97#include <linux/ratelimit.h>
98
99#include <linux/uaccess.h>
100
101#include <linux/kbd_kern.h>
102#include <linux/vt_kern.h>
103#include <linux/selection.h>
104
105#include <linux/kmod.h>
106#include <linux/nsproxy.h>
107
108#undef TTY_DEBUG_HANGUP
109#ifdef TTY_DEBUG_HANGUP
110# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
111#else
112# define tty_debug_hangup(tty, f, args...) do { } while (0)
113#endif
114
115#define TTY_PARANOIA_CHECK 1
116#define CHECK_TTY_COUNT 1
117
118struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
119 .c_iflag = ICRNL | IXON,
120 .c_oflag = OPOST | ONLCR,
121 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
122 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
123 ECHOCTL | ECHOKE | IEXTEN,
124 .c_cc = INIT_C_CC,
125 .c_ispeed = 38400,
126 .c_ospeed = 38400,
127 /* .c_line = N_TTY, */
128};
129
130EXPORT_SYMBOL(tty_std_termios);
131
132/* This list gets poked at by procfs and various bits of boot up code. This
133 could do with some rationalisation such as pulling the tty proc function
134 into this file */
135
136LIST_HEAD(tty_drivers); /* linked list of tty drivers */
137
138/* Mutex to protect creating and releasing a tty */
139DEFINE_MUTEX(tty_mutex);
140
141static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
142static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
143ssize_t redirected_tty_write(struct file *, const char __user *,
144 size_t, loff_t *);
145static unsigned int tty_poll(struct file *, poll_table *);
146static int tty_open(struct inode *, struct file *);
147long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148#ifdef CONFIG_COMPAT
149static long tty_compat_ioctl(struct file *file, unsigned int cmd,
150 unsigned long arg);
151#else
152#define tty_compat_ioctl NULL
153#endif
154static int __tty_fasync(int fd, struct file *filp, int on);
155static int tty_fasync(int fd, struct file *filp, int on);
156static void release_tty(struct tty_struct *tty, int idx);
157
158/**
159 * free_tty_struct - free a disused tty
160 * @tty: tty struct to free
161 *
162 * Free the write buffers, tty queue and tty memory itself.
163 *
164 * Locking: none. Must be called after tty is definitely unused
165 */
166
167static void free_tty_struct(struct tty_struct *tty)
168{
169 tty_ldisc_deinit(tty);
170 put_device(tty->dev);
171 kfree(tty->write_buf);
172 tty->magic = 0xDEADDEAD;
173 kfree(tty);
174}
175
176static inline struct tty_struct *file_tty(struct file *file)
177{
178 return ((struct tty_file_private *)file->private_data)->tty;
179}
180
181int tty_alloc_file(struct file *file)
182{
183 struct tty_file_private *priv;
184
185 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
186 if (!priv)
187 return -ENOMEM;
188
189 file->private_data = priv;
190
191 return 0;
192}
193
194/* Associate a new file with the tty structure */
195void tty_add_file(struct tty_struct *tty, struct file *file)
196{
197 struct tty_file_private *priv = file->private_data;
198
199 priv->tty = tty;
200 priv->file = file;
201
202 spin_lock(&tty->files_lock);
203 list_add(&priv->list, &tty->tty_files);
204 spin_unlock(&tty->files_lock);
205}
206
207/**
208 * tty_free_file - free file->private_data
209 *
210 * This shall be used only for fail path handling when tty_add_file was not
211 * called yet.
212 */
213void tty_free_file(struct file *file)
214{
215 struct tty_file_private *priv = file->private_data;
216
217 file->private_data = NULL;
218 kfree(priv);
219}
220
221/* Delete file from its tty */
222static void tty_del_file(struct file *file)
223{
224 struct tty_file_private *priv = file->private_data;
225 struct tty_struct *tty = priv->tty;
226
227 spin_lock(&tty->files_lock);
228 list_del(&priv->list);
229 spin_unlock(&tty->files_lock);
230 tty_free_file(file);
231}
232
233
234#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
235
236/**
237 * tty_name - return tty naming
238 * @tty: tty structure
239 *
240 * Convert a tty structure into a name. The name reflects the kernel
241 * naming policy and if udev is in use may not reflect user space
242 *
243 * Locking: none
244 */
245
246const char *tty_name(const struct tty_struct *tty)
247{
248 if (!tty) /* Hmm. NULL pointer. That's fun. */
249 return "NULL tty";
250 return tty->name;
251}
252
253EXPORT_SYMBOL(tty_name);
254
255const char *tty_driver_name(const struct tty_struct *tty)
256{
257 if (!tty || !tty->driver)
258 return "";
259 return tty->driver->name;
260}
261
262static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
263 const char *routine)
264{
265#ifdef TTY_PARANOIA_CHECK
266 if (!tty) {
267 pr_warn("(%d:%d): %s: NULL tty\n",
268 imajor(inode), iminor(inode), routine);
269 return 1;
270 }
271 if (tty->magic != TTY_MAGIC) {
272 pr_warn("(%d:%d): %s: bad magic number\n",
273 imajor(inode), iminor(inode), routine);
274 return 1;
275 }
276#endif
277 return 0;
278}
279
280/* Caller must hold tty_lock */
281static int check_tty_count(struct tty_struct *tty, const char *routine)
282{
283#ifdef CHECK_TTY_COUNT
284 struct list_head *p;
285 int count = 0;
286
287 spin_lock(&tty->files_lock);
288 list_for_each(p, &tty->tty_files) {
289 count++;
290 }
291 spin_unlock(&tty->files_lock);
292 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
293 tty->driver->subtype == PTY_TYPE_SLAVE &&
294 tty->link && tty->link->count)
295 count++;
296 if (tty->count != count) {
297 tty_warn(tty, "%s: tty->count(%d) != #fd's(%d)\n",
298 routine, tty->count, count);
299 return count;
300 }
301#endif
302 return 0;
303}
304
305/**
306 * get_tty_driver - find device of a tty
307 * @dev_t: device identifier
308 * @index: returns the index of the tty
309 *
310 * This routine returns a tty driver structure, given a device number
311 * and also passes back the index number.
312 *
313 * Locking: caller must hold tty_mutex
314 */
315
316static struct tty_driver *get_tty_driver(dev_t device, int *index)
317{
318 struct tty_driver *p;
319
320 list_for_each_entry(p, &tty_drivers, tty_drivers) {
321 dev_t base = MKDEV(p->major, p->minor_start);
322 if (device < base || device >= base + p->num)
323 continue;
324 *index = device - base;
325 return tty_driver_kref_get(p);
326 }
327 return NULL;
328}
329
330#ifdef CONFIG_CONSOLE_POLL
331
332/**
333 * tty_find_polling_driver - find device of a polled tty
334 * @name: name string to match
335 * @line: pointer to resulting tty line nr
336 *
337 * This routine returns a tty driver structure, given a name
338 * and the condition that the tty driver is capable of polled
339 * operation.
340 */
341struct tty_driver *tty_find_polling_driver(char *name, int *line)
342{
343 struct tty_driver *p, *res = NULL;
344 int tty_line = 0;
345 int len;
346 char *str, *stp;
347
348 for (str = name; *str; str++)
349 if ((*str >= '0' && *str <= '9') || *str == ',')
350 break;
351 if (!*str)
352 return NULL;
353
354 len = str - name;
355 tty_line = simple_strtoul(str, &str, 10);
356
357 mutex_lock(&tty_mutex);
358 /* Search through the tty devices to look for a match */
359 list_for_each_entry(p, &tty_drivers, tty_drivers) {
360 if (strncmp(name, p->name, len) != 0)
361 continue;
362 stp = str;
363 if (*stp == ',')
364 stp++;
365 if (*stp == '\0')
366 stp = NULL;
367
368 if (tty_line >= 0 && tty_line < p->num && p->ops &&
369 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
370 res = tty_driver_kref_get(p);
371 *line = tty_line;
372 break;
373 }
374 }
375 mutex_unlock(&tty_mutex);
376
377 return res;
378}
379EXPORT_SYMBOL_GPL(tty_find_polling_driver);
380#endif
381
382static int is_ignored(int sig)
383{
384 return (sigismember(¤t->blocked, sig) ||
385 current->sighand->action[sig-1].sa.sa_handler == SIG_IGN);
386}
387
388/**
389 * tty_check_change - check for POSIX terminal changes
390 * @tty: tty to check
391 *
392 * If we try to write to, or set the state of, a terminal and we're
393 * not in the foreground, send a SIGTTOU. If the signal is blocked or
394 * ignored, go ahead and perform the operation. (POSIX 7.2)
395 *
396 * Locking: ctrl_lock
397 */
398
399int __tty_check_change(struct tty_struct *tty, int sig)
400{
401 unsigned long flags;
402 struct pid *pgrp, *tty_pgrp;
403 int ret = 0;
404
405 if (current->signal->tty != tty)
406 return 0;
407
408 rcu_read_lock();
409 pgrp = task_pgrp(current);
410
411 spin_lock_irqsave(&tty->ctrl_lock, flags);
412 tty_pgrp = tty->pgrp;
413 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
414
415 if (tty_pgrp && pgrp != tty->pgrp) {
416 if (is_ignored(sig)) {
417 if (sig == SIGTTIN)
418 ret = -EIO;
419 } else if (is_current_pgrp_orphaned())
420 ret = -EIO;
421 else {
422 kill_pgrp(pgrp, sig, 1);
423 set_thread_flag(TIF_SIGPENDING);
424 ret = -ERESTARTSYS;
425 }
426 }
427 rcu_read_unlock();
428
429 if (!tty_pgrp)
430 tty_warn(tty, "sig=%d, tty->pgrp == NULL!\n", sig);
431
432 return ret;
433}
434
435int tty_check_change(struct tty_struct *tty)
436{
437 return __tty_check_change(tty, SIGTTOU);
438}
439EXPORT_SYMBOL(tty_check_change);
440
441static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
442 size_t count, loff_t *ppos)
443{
444 return 0;
445}
446
447static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
448 size_t count, loff_t *ppos)
449{
450 return -EIO;
451}
452
453/* No kernel lock held - none needed ;) */
454static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
455{
456 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
457}
458
459static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
460 unsigned long arg)
461{
462 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
463}
464
465static long hung_up_tty_compat_ioctl(struct file *file,
466 unsigned int cmd, unsigned long arg)
467{
468 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
469}
470
471static int hung_up_tty_fasync(int fd, struct file *file, int on)
472{
473 return -ENOTTY;
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};
487
488static const struct file_operations console_fops = {
489 .llseek = no_llseek,
490 .read = tty_read,
491 .write = redirected_tty_write,
492 .poll = tty_poll,
493 .unlocked_ioctl = tty_ioctl,
494 .compat_ioctl = tty_compat_ioctl,
495 .open = tty_open,
496 .release = tty_release,
497 .fasync = tty_fasync,
498};
499
500static const struct file_operations hung_up_tty_fops = {
501 .llseek = no_llseek,
502 .read = hung_up_tty_read,
503 .write = hung_up_tty_write,
504 .poll = hung_up_tty_poll,
505 .unlocked_ioctl = hung_up_tty_ioctl,
506 .compat_ioctl = hung_up_tty_compat_ioctl,
507 .release = tty_release,
508 .fasync = hung_up_tty_fasync,
509};
510
511static DEFINE_SPINLOCK(redirect_lock);
512static struct file *redirect;
513
514
515void proc_clear_tty(struct task_struct *p)
516{
517 unsigned long flags;
518 struct tty_struct *tty;
519 spin_lock_irqsave(&p->sighand->siglock, flags);
520 tty = p->signal->tty;
521 p->signal->tty = NULL;
522 spin_unlock_irqrestore(&p->sighand->siglock, flags);
523 tty_kref_put(tty);
524}
525
526/**
527 * proc_set_tty - set the controlling terminal
528 *
529 * Only callable by the session leader and only if it does not already have
530 * a controlling terminal.
531 *
532 * Caller must hold: tty_lock()
533 * a readlock on tasklist_lock
534 * sighand lock
535 */
536static void __proc_set_tty(struct tty_struct *tty)
537{
538 unsigned long flags;
539
540 spin_lock_irqsave(&tty->ctrl_lock, flags);
541 /*
542 * The session and fg pgrp references will be non-NULL if
543 * tiocsctty() is stealing the controlling tty
544 */
545 put_pid(tty->session);
546 put_pid(tty->pgrp);
547 tty->pgrp = get_pid(task_pgrp(current));
548 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
549 tty->session = get_pid(task_session(current));
550 if (current->signal->tty) {
551 tty_debug(tty, "current tty %s not NULL!!\n",
552 current->signal->tty->name);
553 tty_kref_put(current->signal->tty);
554 }
555 put_pid(current->signal->tty_old_pgrp);
556 current->signal->tty = tty_kref_get(tty);
557 current->signal->tty_old_pgrp = NULL;
558}
559
560static void proc_set_tty(struct tty_struct *tty)
561{
562 spin_lock_irq(¤t->sighand->siglock);
563 __proc_set_tty(tty);
564 spin_unlock_irq(¤t->sighand->siglock);
565}
566
567struct tty_struct *get_current_tty(void)
568{
569 struct tty_struct *tty;
570 unsigned long flags;
571
572 spin_lock_irqsave(¤t->sighand->siglock, flags);
573 tty = tty_kref_get(current->signal->tty);
574 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
575 return tty;
576}
577EXPORT_SYMBOL_GPL(get_current_tty);
578
579static void session_clear_tty(struct pid *session)
580{
581 struct task_struct *p;
582 do_each_pid_task(session, PIDTYPE_SID, p) {
583 proc_clear_tty(p);
584 } while_each_pid_task(session, PIDTYPE_SID, p);
585}
586
587/**
588 * tty_wakeup - request more data
589 * @tty: terminal
590 *
591 * Internal and external helper for wakeups of tty. This function
592 * informs the line discipline if present that the driver is ready
593 * to receive more output data.
594 */
595
596void tty_wakeup(struct tty_struct *tty)
597{
598 struct tty_ldisc *ld;
599
600 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
601 ld = tty_ldisc_ref(tty);
602 if (ld) {
603 if (ld->ops->write_wakeup)
604 ld->ops->write_wakeup(tty);
605 tty_ldisc_deref(ld);
606 }
607 }
608 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
609}
610
611EXPORT_SYMBOL_GPL(tty_wakeup);
612
613/**
614 * tty_signal_session_leader - sends SIGHUP to session leader
615 * @tty controlling tty
616 * @exit_session if non-zero, signal all foreground group processes
617 *
618 * Send SIGHUP and SIGCONT to the session leader and its process group.
619 * Optionally, signal all processes in the foreground process group.
620 *
621 * Returns the number of processes in the session with this tty
622 * as their controlling terminal. This value is used to drop
623 * tty references for those processes.
624 */
625static int tty_signal_session_leader(struct tty_struct *tty, int exit_session)
626{
627 struct task_struct *p;
628 int refs = 0;
629 struct pid *tty_pgrp = NULL;
630
631 read_lock(&tasklist_lock);
632 if (tty->session) {
633 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
634 spin_lock_irq(&p->sighand->siglock);
635 if (p->signal->tty == tty) {
636 p->signal->tty = NULL;
637 /* We defer the dereferences outside fo
638 the tasklist lock */
639 refs++;
640 }
641 if (!p->signal->leader) {
642 spin_unlock_irq(&p->sighand->siglock);
643 continue;
644 }
645 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
646 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
647 put_pid(p->signal->tty_old_pgrp); /* A noop */
648 spin_lock(&tty->ctrl_lock);
649 tty_pgrp = get_pid(tty->pgrp);
650 if (tty->pgrp)
651 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
652 spin_unlock(&tty->ctrl_lock);
653 spin_unlock_irq(&p->sighand->siglock);
654 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
655 }
656 read_unlock(&tasklist_lock);
657
658 if (tty_pgrp) {
659 if (exit_session)
660 kill_pgrp(tty_pgrp, SIGHUP, exit_session);
661 put_pid(tty_pgrp);
662 }
663
664 return refs;
665}
666
667/**
668 * __tty_hangup - actual handler for hangup events
669 * @work: tty device
670 *
671 * This can be called by a "kworker" kernel thread. That is process
672 * synchronous but doesn't hold any locks, so we need to make sure we
673 * have the appropriate locks for what we're doing.
674 *
675 * The hangup event clears any pending redirections onto the hung up
676 * device. It ensures future writes will error and it does the needed
677 * line discipline hangup and signal delivery. The tty object itself
678 * remains intact.
679 *
680 * Locking:
681 * BTM
682 * redirect lock for undoing redirection
683 * file list lock for manipulating list of ttys
684 * tty_ldiscs_lock from called functions
685 * termios_rwsem resetting termios data
686 * tasklist_lock to walk task list for hangup event
687 * ->siglock to protect ->signal/->sighand
688 */
689static void __tty_hangup(struct tty_struct *tty, int exit_session)
690{
691 struct file *cons_filp = NULL;
692 struct file *filp, *f = NULL;
693 struct tty_file_private *priv;
694 int closecount = 0, n;
695 int refs;
696
697 if (!tty)
698 return;
699
700
701 spin_lock(&redirect_lock);
702 if (redirect && file_tty(redirect) == tty) {
703 f = redirect;
704 redirect = NULL;
705 }
706 spin_unlock(&redirect_lock);
707
708 tty_lock(tty);
709
710 if (test_bit(TTY_HUPPED, &tty->flags)) {
711 tty_unlock(tty);
712 return;
713 }
714
715 /* inuse_filps is protected by the single tty lock,
716 this really needs to change if we want to flush the
717 workqueue with the lock held */
718 check_tty_count(tty, "tty_hangup");
719
720 spin_lock(&tty->files_lock);
721 /* This breaks for file handles being sent over AF_UNIX sockets ? */
722 list_for_each_entry(priv, &tty->tty_files, list) {
723 filp = priv->file;
724 if (filp->f_op->write == redirected_tty_write)
725 cons_filp = filp;
726 if (filp->f_op->write != tty_write)
727 continue;
728 closecount++;
729 __tty_fasync(-1, filp, 0); /* can't block */
730 filp->f_op = &hung_up_tty_fops;
731 }
732 spin_unlock(&tty->files_lock);
733
734 refs = tty_signal_session_leader(tty, exit_session);
735 /* Account for the p->signal references we killed */
736 while (refs--)
737 tty_kref_put(tty);
738
739 tty_ldisc_hangup(tty, cons_filp != NULL);
740
741 spin_lock_irq(&tty->ctrl_lock);
742 clear_bit(TTY_THROTTLED, &tty->flags);
743 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
744 put_pid(tty->session);
745 put_pid(tty->pgrp);
746 tty->session = NULL;
747 tty->pgrp = NULL;
748 tty->ctrl_status = 0;
749 spin_unlock_irq(&tty->ctrl_lock);
750
751 /*
752 * If one of the devices matches a console pointer, we
753 * cannot just call hangup() because that will cause
754 * tty->count and state->count to go out of sync.
755 * So we just call close() the right number of times.
756 */
757 if (cons_filp) {
758 if (tty->ops->close)
759 for (n = 0; n < closecount; n++)
760 tty->ops->close(tty, cons_filp);
761 } else if (tty->ops->hangup)
762 tty->ops->hangup(tty);
763 /*
764 * We don't want to have driver/ldisc interactions beyond the ones
765 * we did here. The driver layer expects no calls after ->hangup()
766 * from the ldisc side, which is now guaranteed.
767 */
768 set_bit(TTY_HUPPED, &tty->flags);
769 tty_unlock(tty);
770
771 if (f)
772 fput(f);
773}
774
775static void do_tty_hangup(struct work_struct *work)
776{
777 struct tty_struct *tty =
778 container_of(work, struct tty_struct, hangup_work);
779
780 __tty_hangup(tty, 0);
781}
782
783/**
784 * tty_hangup - trigger a hangup event
785 * @tty: tty to hangup
786 *
787 * A carrier loss (virtual or otherwise) has occurred on this like
788 * schedule a hangup sequence to run after this event.
789 */
790
791void tty_hangup(struct tty_struct *tty)
792{
793 tty_debug_hangup(tty, "hangup\n");
794 schedule_work(&tty->hangup_work);
795}
796
797EXPORT_SYMBOL(tty_hangup);
798
799/**
800 * tty_vhangup - process vhangup
801 * @tty: tty to hangup
802 *
803 * The user has asked via system call for the terminal to be hung up.
804 * We do this synchronously so that when the syscall returns the process
805 * is complete. That guarantee is necessary for security reasons.
806 */
807
808void tty_vhangup(struct tty_struct *tty)
809{
810 tty_debug_hangup(tty, "vhangup\n");
811 __tty_hangup(tty, 0);
812}
813
814EXPORT_SYMBOL(tty_vhangup);
815
816
817/**
818 * tty_vhangup_self - process vhangup for own ctty
819 *
820 * Perform a vhangup on the current controlling tty
821 */
822
823void tty_vhangup_self(void)
824{
825 struct tty_struct *tty;
826
827 tty = get_current_tty();
828 if (tty) {
829 tty_vhangup(tty);
830 tty_kref_put(tty);
831 }
832}
833
834/**
835 * tty_vhangup_session - hangup session leader exit
836 * @tty: tty to hangup
837 *
838 * The session leader is exiting and hanging up its controlling terminal.
839 * Every process in the foreground process group is signalled SIGHUP.
840 *
841 * We do this synchronously so that when the syscall returns the process
842 * is complete. That guarantee is necessary for security reasons.
843 */
844
845static void tty_vhangup_session(struct tty_struct *tty)
846{
847 tty_debug_hangup(tty, "session hangup\n");
848 __tty_hangup(tty, 1);
849}
850
851/**
852 * tty_hung_up_p - was tty hung up
853 * @filp: file pointer of tty
854 *
855 * Return true if the tty has been subject to a vhangup or a carrier
856 * loss
857 */
858
859int tty_hung_up_p(struct file *filp)
860{
861 return (filp->f_op == &hung_up_tty_fops);
862}
863
864EXPORT_SYMBOL(tty_hung_up_p);
865
866/**
867 * disassociate_ctty - disconnect controlling tty
868 * @on_exit: true if exiting so need to "hang up" the session
869 *
870 * This function is typically called only by the session leader, when
871 * it wants to disassociate itself from its controlling tty.
872 *
873 * It performs the following functions:
874 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
875 * (2) Clears the tty from being controlling the session
876 * (3) Clears the controlling tty for all processes in the
877 * session group.
878 *
879 * The argument on_exit is set to 1 if called when a process is
880 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
881 *
882 * Locking:
883 * BTM is taken for hysterical raisins, and held when
884 * called from no_tty().
885 * tty_mutex is taken to protect tty
886 * ->siglock is taken to protect ->signal/->sighand
887 * tasklist_lock is taken to walk process list for sessions
888 * ->siglock is taken to protect ->signal/->sighand
889 */
890
891void disassociate_ctty(int on_exit)
892{
893 struct tty_struct *tty;
894
895 if (!current->signal->leader)
896 return;
897
898 tty = get_current_tty();
899 if (tty) {
900 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
901 tty_vhangup_session(tty);
902 } else {
903 struct pid *tty_pgrp = tty_get_pgrp(tty);
904 if (tty_pgrp) {
905 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
906 if (!on_exit)
907 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
908 put_pid(tty_pgrp);
909 }
910 }
911 tty_kref_put(tty);
912
913 } else if (on_exit) {
914 struct pid *old_pgrp;
915 spin_lock_irq(¤t->sighand->siglock);
916 old_pgrp = current->signal->tty_old_pgrp;
917 current->signal->tty_old_pgrp = NULL;
918 spin_unlock_irq(¤t->sighand->siglock);
919 if (old_pgrp) {
920 kill_pgrp(old_pgrp, SIGHUP, on_exit);
921 kill_pgrp(old_pgrp, SIGCONT, on_exit);
922 put_pid(old_pgrp);
923 }
924 return;
925 }
926
927 spin_lock_irq(¤t->sighand->siglock);
928 put_pid(current->signal->tty_old_pgrp);
929 current->signal->tty_old_pgrp = NULL;
930
931 tty = tty_kref_get(current->signal->tty);
932 if (tty) {
933 unsigned long flags;
934 spin_lock_irqsave(&tty->ctrl_lock, flags);
935 put_pid(tty->session);
936 put_pid(tty->pgrp);
937 tty->session = NULL;
938 tty->pgrp = NULL;
939 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
940 tty_kref_put(tty);
941 } else
942 tty_debug_hangup(tty, "no current tty\n");
943
944 spin_unlock_irq(¤t->sighand->siglock);
945 /* Now clear signal->tty under the lock */
946 read_lock(&tasklist_lock);
947 session_clear_tty(task_session(current));
948 read_unlock(&tasklist_lock);
949}
950
951/**
952 *
953 * no_tty - Ensure the current process does not have a controlling tty
954 */
955void no_tty(void)
956{
957 /* FIXME: Review locking here. The tty_lock never covered any race
958 between a new association and proc_clear_tty but possible we need
959 to protect against this anyway */
960 struct task_struct *tsk = current;
961 disassociate_ctty(0);
962 proc_clear_tty(tsk);
963}
964
965
966/**
967 * stop_tty - propagate flow control
968 * @tty: tty to stop
969 *
970 * Perform flow control to the driver. May be called
971 * on an already stopped device and will not re-call the driver
972 * method.
973 *
974 * This functionality is used by both the line disciplines for
975 * halting incoming flow and by the driver. It may therefore be
976 * called from any context, may be under the tty atomic_write_lock
977 * but not always.
978 *
979 * Locking:
980 * flow_lock
981 */
982
983void __stop_tty(struct tty_struct *tty)
984{
985 if (tty->stopped)
986 return;
987 tty->stopped = 1;
988 if (tty->ops->stop)
989 tty->ops->stop(tty);
990}
991
992void stop_tty(struct tty_struct *tty)
993{
994 unsigned long flags;
995
996 spin_lock_irqsave(&tty->flow_lock, flags);
997 __stop_tty(tty);
998 spin_unlock_irqrestore(&tty->flow_lock, flags);
999}
1000EXPORT_SYMBOL(stop_tty);
1001
1002/**
1003 * start_tty - propagate flow control
1004 * @tty: tty to start
1005 *
1006 * Start a tty that has been stopped if at all possible. If this
1007 * tty was previous stopped and is now being started, the driver
1008 * start method is invoked and the line discipline woken.
1009 *
1010 * Locking:
1011 * flow_lock
1012 */
1013
1014void __start_tty(struct tty_struct *tty)
1015{
1016 if (!tty->stopped || tty->flow_stopped)
1017 return;
1018 tty->stopped = 0;
1019 if (tty->ops->start)
1020 tty->ops->start(tty);
1021 tty_wakeup(tty);
1022}
1023
1024void start_tty(struct tty_struct *tty)
1025{
1026 unsigned long flags;
1027
1028 spin_lock_irqsave(&tty->flow_lock, flags);
1029 __start_tty(tty);
1030 spin_unlock_irqrestore(&tty->flow_lock, flags);
1031}
1032EXPORT_SYMBOL(start_tty);
1033
1034static void tty_update_time(struct timespec *time)
1035{
1036 unsigned long sec = get_seconds();
1037
1038 /*
1039 * We only care if the two values differ in anything other than the
1040 * lower three bits (i.e every 8 seconds). If so, then we can update
1041 * the time of the tty device, otherwise it could be construded as a
1042 * security leak to let userspace know the exact timing of the tty.
1043 */
1044 if ((sec ^ time->tv_sec) & ~7)
1045 time->tv_sec = sec;
1046}
1047
1048/**
1049 * tty_read - read method for tty device files
1050 * @file: pointer to tty file
1051 * @buf: user buffer
1052 * @count: size of user buffer
1053 * @ppos: unused
1054 *
1055 * Perform the read system call function on this terminal device. Checks
1056 * for hung up devices before calling the line discipline method.
1057 *
1058 * Locking:
1059 * Locks the line discipline internally while needed. Multiple
1060 * read calls may be outstanding in parallel.
1061 */
1062
1063static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
1064 loff_t *ppos)
1065{
1066 int i;
1067 struct inode *inode = file_inode(file);
1068 struct tty_struct *tty = file_tty(file);
1069 struct tty_ldisc *ld;
1070
1071 if (tty_paranoia_check(tty, inode, "tty_read"))
1072 return -EIO;
1073 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1074 return -EIO;
1075
1076 /* We want to wait for the line discipline to sort out in this
1077 situation */
1078 ld = tty_ldisc_ref_wait(tty);
1079 if (!ld)
1080 return hung_up_tty_read(file, buf, count, ppos);
1081 if (ld->ops->read)
1082 i = ld->ops->read(tty, file, buf, count);
1083 else
1084 i = -EIO;
1085 tty_ldisc_deref(ld);
1086
1087 if (i > 0)
1088 tty_update_time(&inode->i_atime);
1089
1090 return i;
1091}
1092
1093static void tty_write_unlock(struct tty_struct *tty)
1094{
1095 mutex_unlock(&tty->atomic_write_lock);
1096 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
1097}
1098
1099static int tty_write_lock(struct tty_struct *tty, int ndelay)
1100{
1101 if (!mutex_trylock(&tty->atomic_write_lock)) {
1102 if (ndelay)
1103 return -EAGAIN;
1104 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1105 return -ERESTARTSYS;
1106 }
1107 return 0;
1108}
1109
1110/*
1111 * Split writes up in sane blocksizes to avoid
1112 * denial-of-service type attacks
1113 */
1114static inline ssize_t do_tty_write(
1115 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1116 struct tty_struct *tty,
1117 struct file *file,
1118 const char __user *buf,
1119 size_t count)
1120{
1121 ssize_t ret, written = 0;
1122 unsigned int chunk;
1123
1124 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1125 if (ret < 0)
1126 return ret;
1127
1128 /*
1129 * We chunk up writes into a temporary buffer. This
1130 * simplifies low-level drivers immensely, since they
1131 * don't have locking issues and user mode accesses.
1132 *
1133 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1134 * big chunk-size..
1135 *
1136 * The default chunk-size is 2kB, because the NTTY
1137 * layer has problems with bigger chunks. It will
1138 * claim to be able to handle more characters than
1139 * it actually does.
1140 *
1141 * FIXME: This can probably go away now except that 64K chunks
1142 * are too likely to fail unless switched to vmalloc...
1143 */
1144 chunk = 2048;
1145 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1146 chunk = 65536;
1147 if (count < chunk)
1148 chunk = count;
1149
1150 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1151 if (tty->write_cnt < chunk) {
1152 unsigned char *buf_chunk;
1153
1154 if (chunk < 1024)
1155 chunk = 1024;
1156
1157 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1158 if (!buf_chunk) {
1159 ret = -ENOMEM;
1160 goto out;
1161 }
1162 kfree(tty->write_buf);
1163 tty->write_cnt = chunk;
1164 tty->write_buf = buf_chunk;
1165 }
1166
1167 /* Do the write .. */
1168 for (;;) {
1169 size_t size = count;
1170 if (size > chunk)
1171 size = chunk;
1172 ret = -EFAULT;
1173 if (copy_from_user(tty->write_buf, buf, size))
1174 break;
1175 ret = write(tty, file, tty->write_buf, size);
1176 if (ret <= 0)
1177 break;
1178 written += ret;
1179 buf += ret;
1180 count -= ret;
1181 if (!count)
1182 break;
1183 ret = -ERESTARTSYS;
1184 if (signal_pending(current))
1185 break;
1186 cond_resched();
1187 }
1188 if (written) {
1189 tty_update_time(&file_inode(file)->i_mtime);
1190 ret = written;
1191 }
1192out:
1193 tty_write_unlock(tty);
1194 return ret;
1195}
1196
1197/**
1198 * tty_write_message - write a message to a certain tty, not just the console.
1199 * @tty: the destination tty_struct
1200 * @msg: the message to write
1201 *
1202 * This is used for messages that need to be redirected to a specific tty.
1203 * We don't put it into the syslog queue right now maybe in the future if
1204 * really needed.
1205 *
1206 * We must still hold the BTM and test the CLOSING flag for the moment.
1207 */
1208
1209void tty_write_message(struct tty_struct *tty, char *msg)
1210{
1211 if (tty) {
1212 mutex_lock(&tty->atomic_write_lock);
1213 tty_lock(tty);
1214 if (tty->ops->write && tty->count > 0)
1215 tty->ops->write(tty, msg, strlen(msg));
1216 tty_unlock(tty);
1217 tty_write_unlock(tty);
1218 }
1219 return;
1220}
1221
1222
1223/**
1224 * tty_write - write method for tty device file
1225 * @file: tty file pointer
1226 * @buf: user data to write
1227 * @count: bytes to write
1228 * @ppos: unused
1229 *
1230 * Write data to a tty device via the line discipline.
1231 *
1232 * Locking:
1233 * Locks the line discipline as required
1234 * Writes to the tty driver are serialized by the atomic_write_lock
1235 * and are then processed in chunks to the device. The line discipline
1236 * write method will not be invoked in parallel for each device.
1237 */
1238
1239static ssize_t tty_write(struct file *file, const char __user *buf,
1240 size_t count, loff_t *ppos)
1241{
1242 struct tty_struct *tty = file_tty(file);
1243 struct tty_ldisc *ld;
1244 ssize_t ret;
1245
1246 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1247 return -EIO;
1248 if (!tty || !tty->ops->write ||
1249 (test_bit(TTY_IO_ERROR, &tty->flags)))
1250 return -EIO;
1251 /* Short term debug to catch buggy drivers */
1252 if (tty->ops->write_room == NULL)
1253 tty_err(tty, "missing write_room method\n");
1254 ld = tty_ldisc_ref_wait(tty);
1255 if (!ld)
1256 return hung_up_tty_write(file, buf, count, ppos);
1257 if (!ld->ops->write)
1258 ret = -EIO;
1259 else
1260 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1261 tty_ldisc_deref(ld);
1262 return ret;
1263}
1264
1265ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1266 size_t count, loff_t *ppos)
1267{
1268 struct file *p = NULL;
1269
1270 spin_lock(&redirect_lock);
1271 if (redirect)
1272 p = get_file(redirect);
1273 spin_unlock(&redirect_lock);
1274
1275 if (p) {
1276 ssize_t res;
1277 res = vfs_write(p, buf, count, &p->f_pos);
1278 fput(p);
1279 return res;
1280 }
1281 return tty_write(file, buf, count, ppos);
1282}
1283
1284/**
1285 * tty_send_xchar - send priority character
1286 *
1287 * Send a high priority character to the tty even if stopped
1288 *
1289 * Locking: none for xchar method, write ordering for write method.
1290 */
1291
1292int tty_send_xchar(struct tty_struct *tty, char ch)
1293{
1294 int was_stopped = tty->stopped;
1295
1296 if (tty->ops->send_xchar) {
1297 down_read(&tty->termios_rwsem);
1298 tty->ops->send_xchar(tty, ch);
1299 up_read(&tty->termios_rwsem);
1300 return 0;
1301 }
1302
1303 if (tty_write_lock(tty, 0) < 0)
1304 return -ERESTARTSYS;
1305
1306 down_read(&tty->termios_rwsem);
1307 if (was_stopped)
1308 start_tty(tty);
1309 tty->ops->write(tty, &ch, 1);
1310 if (was_stopped)
1311 stop_tty(tty);
1312 up_read(&tty->termios_rwsem);
1313 tty_write_unlock(tty);
1314 return 0;
1315}
1316
1317static char ptychar[] = "pqrstuvwxyzabcde";
1318
1319/**
1320 * pty_line_name - generate name for a pty
1321 * @driver: the tty driver in use
1322 * @index: the minor number
1323 * @p: output buffer of at least 6 bytes
1324 *
1325 * Generate a name from a driver reference and write it to the output
1326 * buffer.
1327 *
1328 * Locking: None
1329 */
1330static void pty_line_name(struct tty_driver *driver, int index, char *p)
1331{
1332 int i = index + driver->name_base;
1333 /* ->name is initialized to "ttyp", but "tty" is expected */
1334 sprintf(p, "%s%c%x",
1335 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1336 ptychar[i >> 4 & 0xf], i & 0xf);
1337}
1338
1339/**
1340 * tty_line_name - generate name for a tty
1341 * @driver: the tty driver in use
1342 * @index: the minor number
1343 * @p: output buffer of at least 7 bytes
1344 *
1345 * Generate a name from a driver reference and write it to the output
1346 * buffer.
1347 *
1348 * Locking: None
1349 */
1350static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1351{
1352 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1353 return sprintf(p, "%s", driver->name);
1354 else
1355 return sprintf(p, "%s%d", driver->name,
1356 index + driver->name_base);
1357}
1358
1359/**
1360 * tty_driver_lookup_tty() - find an existing tty, if any
1361 * @driver: the driver for the tty
1362 * @idx: the minor number
1363 *
1364 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1365 * driver lookup() method returns an error.
1366 *
1367 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1368 */
1369static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1370 struct file *file, int idx)
1371{
1372 struct tty_struct *tty;
1373
1374 if (driver->ops->lookup)
1375 tty = driver->ops->lookup(driver, file, idx);
1376 else
1377 tty = driver->ttys[idx];
1378
1379 if (!IS_ERR(tty))
1380 tty_kref_get(tty);
1381 return tty;
1382}
1383
1384/**
1385 * tty_init_termios - helper for termios setup
1386 * @tty: the tty to set up
1387 *
1388 * Initialise the termios structures for this tty. Thus runs under
1389 * the tty_mutex currently so we can be relaxed about ordering.
1390 */
1391
1392void tty_init_termios(struct tty_struct *tty)
1393{
1394 struct ktermios *tp;
1395 int idx = tty->index;
1396
1397 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1398 tty->termios = tty->driver->init_termios;
1399 else {
1400 /* Check for lazy saved data */
1401 tp = tty->driver->termios[idx];
1402 if (tp != NULL) {
1403 tty->termios = *tp;
1404 tty->termios.c_line = tty->driver->init_termios.c_line;
1405 } else
1406 tty->termios = tty->driver->init_termios;
1407 }
1408 /* Compatibility until drivers always set this */
1409 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1410 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1411}
1412EXPORT_SYMBOL_GPL(tty_init_termios);
1413
1414int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1415{
1416 tty_init_termios(tty);
1417 tty_driver_kref_get(driver);
1418 tty->count++;
1419 driver->ttys[tty->index] = tty;
1420 return 0;
1421}
1422EXPORT_SYMBOL_GPL(tty_standard_install);
1423
1424/**
1425 * tty_driver_install_tty() - install a tty entry in the driver
1426 * @driver: the driver for the tty
1427 * @tty: the tty
1428 *
1429 * Install a tty object into the driver tables. The tty->index field
1430 * will be set by the time this is called. This method is responsible
1431 * for ensuring any need additional structures are allocated and
1432 * configured.
1433 *
1434 * Locking: tty_mutex for now
1435 */
1436static int tty_driver_install_tty(struct tty_driver *driver,
1437 struct tty_struct *tty)
1438{
1439 return driver->ops->install ? driver->ops->install(driver, tty) :
1440 tty_standard_install(driver, tty);
1441}
1442
1443/**
1444 * tty_driver_remove_tty() - remove a tty from the driver tables
1445 * @driver: the driver for the tty
1446 * @idx: the minor number
1447 *
1448 * Remvoe a tty object from the driver tables. The tty->index field
1449 * will be set by the time this is called.
1450 *
1451 * Locking: tty_mutex for now
1452 */
1453static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1454{
1455 if (driver->ops->remove)
1456 driver->ops->remove(driver, tty);
1457 else
1458 driver->ttys[tty->index] = NULL;
1459}
1460
1461/*
1462 * tty_reopen() - fast re-open of an open tty
1463 * @tty - the tty to open
1464 *
1465 * Return 0 on success, -errno on error.
1466 * Re-opens on master ptys are not allowed and return -EIO.
1467 *
1468 * Locking: Caller must hold tty_lock
1469 */
1470static int tty_reopen(struct tty_struct *tty)
1471{
1472 struct tty_driver *driver = tty->driver;
1473
1474 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1475 driver->subtype == PTY_TYPE_MASTER)
1476 return -EIO;
1477
1478 if (!tty->count)
1479 return -EAGAIN;
1480
1481 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1482 return -EBUSY;
1483
1484 tty->count++;
1485
1486 if (!tty->ldisc)
1487 return tty_ldisc_reinit(tty, tty->termios.c_line);
1488
1489 return 0;
1490}
1491
1492/**
1493 * tty_init_dev - initialise a tty device
1494 * @driver: tty driver we are opening a device on
1495 * @idx: device index
1496 * @ret_tty: returned tty structure
1497 *
1498 * Prepare a tty device. This may not be a "new" clean device but
1499 * could also be an active device. The pty drivers require special
1500 * handling because of this.
1501 *
1502 * Locking:
1503 * The function is called under the tty_mutex, which
1504 * protects us from the tty struct or driver itself going away.
1505 *
1506 * On exit the tty device has the line discipline attached and
1507 * a reference count of 1. If a pair was created for pty/tty use
1508 * and the other was a pty master then it too has a reference count of 1.
1509 *
1510 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1511 * failed open. The new code protects the open with a mutex, so it's
1512 * really quite straightforward. The mutex locking can probably be
1513 * relaxed for the (most common) case of reopening a tty.
1514 */
1515
1516struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1517{
1518 struct tty_struct *tty;
1519 int retval;
1520
1521 /*
1522 * First time open is complex, especially for PTY devices.
1523 * This code guarantees that either everything succeeds and the
1524 * TTY is ready for operation, or else the table slots are vacated
1525 * and the allocated memory released. (Except that the termios
1526 * and locked termios may be retained.)
1527 */
1528
1529 if (!try_module_get(driver->owner))
1530 return ERR_PTR(-ENODEV);
1531
1532 tty = alloc_tty_struct(driver, idx);
1533 if (!tty) {
1534 retval = -ENOMEM;
1535 goto err_module_put;
1536 }
1537
1538 tty_lock(tty);
1539 retval = tty_driver_install_tty(driver, tty);
1540 if (retval < 0)
1541 goto err_free_tty;
1542
1543 if (!tty->port)
1544 tty->port = driver->ports[idx];
1545
1546 WARN_RATELIMIT(!tty->port,
1547 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1548 __func__, tty->driver->name);
1549
1550 tty->port->itty = tty;
1551
1552 /*
1553 * Structures all installed ... call the ldisc open routines.
1554 * If we fail here just call release_tty to clean up. No need
1555 * to decrement the use counts, as release_tty doesn't care.
1556 */
1557 retval = tty_ldisc_setup(tty, tty->link);
1558 if (retval)
1559 goto err_release_tty;
1560 /* Return the tty locked so that it cannot vanish under the caller */
1561 return tty;
1562
1563err_free_tty:
1564 tty_unlock(tty);
1565 free_tty_struct(tty);
1566err_module_put:
1567 module_put(driver->owner);
1568 return ERR_PTR(retval);
1569
1570 /* call the tty release_tty routine to clean out this slot */
1571err_release_tty:
1572 tty_unlock(tty);
1573 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1574 retval, idx);
1575 release_tty(tty, idx);
1576 return ERR_PTR(retval);
1577}
1578
1579static void tty_free_termios(struct tty_struct *tty)
1580{
1581 struct ktermios *tp;
1582 int idx = tty->index;
1583
1584 /* If the port is going to reset then it has no termios to save */
1585 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1586 return;
1587
1588 /* Stash the termios data */
1589 tp = tty->driver->termios[idx];
1590 if (tp == NULL) {
1591 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1592 if (tp == NULL)
1593 return;
1594 tty->driver->termios[idx] = tp;
1595 }
1596 *tp = tty->termios;
1597}
1598
1599/**
1600 * tty_flush_works - flush all works of a tty/pty pair
1601 * @tty: tty device to flush works for (or either end of a pty pair)
1602 *
1603 * Sync flush all works belonging to @tty (and the 'other' tty).
1604 */
1605static void tty_flush_works(struct tty_struct *tty)
1606{
1607 flush_work(&tty->SAK_work);
1608 flush_work(&tty->hangup_work);
1609 if (tty->link) {
1610 flush_work(&tty->link->SAK_work);
1611 flush_work(&tty->link->hangup_work);
1612 }
1613}
1614
1615/**
1616 * release_one_tty - release tty structure memory
1617 * @kref: kref of tty we are obliterating
1618 *
1619 * Releases memory associated with a tty structure, and clears out the
1620 * driver table slots. This function is called when a device is no longer
1621 * in use. It also gets called when setup of a device fails.
1622 *
1623 * Locking:
1624 * takes the file list lock internally when working on the list
1625 * of ttys that the driver keeps.
1626 *
1627 * This method gets called from a work queue so that the driver private
1628 * cleanup ops can sleep (needed for USB at least)
1629 */
1630static void release_one_tty(struct work_struct *work)
1631{
1632 struct tty_struct *tty =
1633 container_of(work, struct tty_struct, hangup_work);
1634 struct tty_driver *driver = tty->driver;
1635 struct module *owner = driver->owner;
1636
1637 if (tty->ops->cleanup)
1638 tty->ops->cleanup(tty);
1639
1640 tty->magic = 0;
1641 tty_driver_kref_put(driver);
1642 module_put(owner);
1643
1644 spin_lock(&tty->files_lock);
1645 list_del_init(&tty->tty_files);
1646 spin_unlock(&tty->files_lock);
1647
1648 put_pid(tty->pgrp);
1649 put_pid(tty->session);
1650 free_tty_struct(tty);
1651}
1652
1653static void queue_release_one_tty(struct kref *kref)
1654{
1655 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1656
1657 /* The hangup queue is now free so we can reuse it rather than
1658 waste a chunk of memory for each port */
1659 INIT_WORK(&tty->hangup_work, release_one_tty);
1660 schedule_work(&tty->hangup_work);
1661}
1662
1663/**
1664 * tty_kref_put - release a tty kref
1665 * @tty: tty device
1666 *
1667 * Release a reference to a tty device and if need be let the kref
1668 * layer destruct the object for us
1669 */
1670
1671void tty_kref_put(struct tty_struct *tty)
1672{
1673 if (tty)
1674 kref_put(&tty->kref, queue_release_one_tty);
1675}
1676EXPORT_SYMBOL(tty_kref_put);
1677
1678/**
1679 * release_tty - release tty structure memory
1680 *
1681 * Release both @tty and a possible linked partner (think pty pair),
1682 * and decrement the refcount of the backing module.
1683 *
1684 * Locking:
1685 * tty_mutex
1686 * takes the file list lock internally when working on the list
1687 * of ttys that the driver keeps.
1688 *
1689 */
1690static void release_tty(struct tty_struct *tty, int idx)
1691{
1692 /* This should always be true but check for the moment */
1693 WARN_ON(tty->index != idx);
1694 WARN_ON(!mutex_is_locked(&tty_mutex));
1695 if (tty->ops->shutdown)
1696 tty->ops->shutdown(tty);
1697 tty_free_termios(tty);
1698 tty_driver_remove_tty(tty->driver, tty);
1699 tty->port->itty = NULL;
1700 if (tty->link)
1701 tty->link->port->itty = NULL;
1702 tty_buffer_cancel_work(tty->port);
1703
1704 tty_kref_put(tty->link);
1705 tty_kref_put(tty);
1706}
1707
1708/**
1709 * tty_release_checks - check a tty before real release
1710 * @tty: tty to check
1711 * @o_tty: link of @tty (if any)
1712 * @idx: index of the tty
1713 *
1714 * Performs some paranoid checking before true release of the @tty.
1715 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1716 */
1717static int tty_release_checks(struct tty_struct *tty, int idx)
1718{
1719#ifdef TTY_PARANOIA_CHECK
1720 if (idx < 0 || idx >= tty->driver->num) {
1721 tty_debug(tty, "bad idx %d\n", idx);
1722 return -1;
1723 }
1724
1725 /* not much to check for devpts */
1726 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1727 return 0;
1728
1729 if (tty != tty->driver->ttys[idx]) {
1730 tty_debug(tty, "bad driver table[%d] = %p\n",
1731 idx, tty->driver->ttys[idx]);
1732 return -1;
1733 }
1734 if (tty->driver->other) {
1735 struct tty_struct *o_tty = tty->link;
1736
1737 if (o_tty != tty->driver->other->ttys[idx]) {
1738 tty_debug(tty, "bad other table[%d] = %p\n",
1739 idx, tty->driver->other->ttys[idx]);
1740 return -1;
1741 }
1742 if (o_tty->link != tty) {
1743 tty_debug(tty, "bad link = %p\n", o_tty->link);
1744 return -1;
1745 }
1746 }
1747#endif
1748 return 0;
1749}
1750
1751/**
1752 * tty_release - vfs callback for close
1753 * @inode: inode of tty
1754 * @filp: file pointer for handle to tty
1755 *
1756 * Called the last time each file handle is closed that references
1757 * this tty. There may however be several such references.
1758 *
1759 * Locking:
1760 * Takes bkl. See tty_release_dev
1761 *
1762 * Even releasing the tty structures is a tricky business.. We have
1763 * to be very careful that the structures are all released at the
1764 * same time, as interrupts might otherwise get the wrong pointers.
1765 *
1766 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1767 * lead to double frees or releasing memory still in use.
1768 */
1769
1770int tty_release(struct inode *inode, struct file *filp)
1771{
1772 struct tty_struct *tty = file_tty(filp);
1773 struct tty_struct *o_tty = NULL;
1774 int do_sleep, final;
1775 int idx;
1776 long timeout = 0;
1777 int once = 1;
1778
1779 if (tty_paranoia_check(tty, inode, __func__))
1780 return 0;
1781
1782 tty_lock(tty);
1783 check_tty_count(tty, __func__);
1784
1785 __tty_fasync(-1, filp, 0);
1786
1787 idx = tty->index;
1788 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1789 tty->driver->subtype == PTY_TYPE_MASTER)
1790 o_tty = tty->link;
1791
1792 if (tty_release_checks(tty, idx)) {
1793 tty_unlock(tty);
1794 return 0;
1795 }
1796
1797 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1798
1799 if (tty->ops->close)
1800 tty->ops->close(tty, filp);
1801
1802 /* If tty is pty master, lock the slave pty (stable lock order) */
1803 tty_lock_slave(o_tty);
1804
1805 /*
1806 * Sanity check: if tty->count is going to zero, there shouldn't be
1807 * any waiters on tty->read_wait or tty->write_wait. We test the
1808 * wait queues and kick everyone out _before_ actually starting to
1809 * close. This ensures that we won't block while releasing the tty
1810 * structure.
1811 *
1812 * The test for the o_tty closing is necessary, since the master and
1813 * slave sides may close in any order. If the slave side closes out
1814 * first, its count will be one, since the master side holds an open.
1815 * Thus this test wouldn't be triggered at the time the slave closed,
1816 * so we do it now.
1817 */
1818 while (1) {
1819 do_sleep = 0;
1820
1821 if (tty->count <= 1) {
1822 if (waitqueue_active(&tty->read_wait)) {
1823 wake_up_poll(&tty->read_wait, POLLIN);
1824 do_sleep++;
1825 }
1826 if (waitqueue_active(&tty->write_wait)) {
1827 wake_up_poll(&tty->write_wait, POLLOUT);
1828 do_sleep++;
1829 }
1830 }
1831 if (o_tty && o_tty->count <= 1) {
1832 if (waitqueue_active(&o_tty->read_wait)) {
1833 wake_up_poll(&o_tty->read_wait, POLLIN);
1834 do_sleep++;
1835 }
1836 if (waitqueue_active(&o_tty->write_wait)) {
1837 wake_up_poll(&o_tty->write_wait, POLLOUT);
1838 do_sleep++;
1839 }
1840 }
1841 if (!do_sleep)
1842 break;
1843
1844 if (once) {
1845 once = 0;
1846 tty_warn(tty, "read/write wait queue active!\n");
1847 }
1848 schedule_timeout_killable(timeout);
1849 if (timeout < 120 * HZ)
1850 timeout = 2 * timeout + 1;
1851 else
1852 timeout = MAX_SCHEDULE_TIMEOUT;
1853 }
1854
1855 if (o_tty) {
1856 if (--o_tty->count < 0) {
1857 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1858 o_tty->count = 0;
1859 }
1860 }
1861 if (--tty->count < 0) {
1862 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1863 tty->count = 0;
1864 }
1865
1866 /*
1867 * We've decremented tty->count, so we need to remove this file
1868 * descriptor off the tty->tty_files list; this serves two
1869 * purposes:
1870 * - check_tty_count sees the correct number of file descriptors
1871 * associated with this tty.
1872 * - do_tty_hangup no longer sees this file descriptor as
1873 * something that needs to be handled for hangups.
1874 */
1875 tty_del_file(filp);
1876
1877 /*
1878 * Perform some housekeeping before deciding whether to return.
1879 *
1880 * If _either_ side is closing, make sure there aren't any
1881 * processes that still think tty or o_tty is their controlling
1882 * tty.
1883 */
1884 if (!tty->count) {
1885 read_lock(&tasklist_lock);
1886 session_clear_tty(tty->session);
1887 if (o_tty)
1888 session_clear_tty(o_tty->session);
1889 read_unlock(&tasklist_lock);
1890 }
1891
1892 /* check whether both sides are closing ... */
1893 final = !tty->count && !(o_tty && o_tty->count);
1894
1895 tty_unlock_slave(o_tty);
1896 tty_unlock(tty);
1897
1898 /* At this point, the tty->count == 0 should ensure a dead tty
1899 cannot be re-opened by a racing opener */
1900
1901 if (!final)
1902 return 0;
1903
1904 tty_debug_hangup(tty, "final close\n");
1905 /*
1906 * Ask the line discipline code to release its structures
1907 */
1908 tty_ldisc_release(tty);
1909
1910 /* Wait for pending work before tty destruction commmences */
1911 tty_flush_works(tty);
1912
1913 tty_debug_hangup(tty, "freeing structure\n");
1914 /*
1915 * The release_tty function takes care of the details of clearing
1916 * the slots and preserving the termios structure. The tty_unlock_pair
1917 * should be safe as we keep a kref while the tty is locked (so the
1918 * unlock never unlocks a freed tty).
1919 */
1920 mutex_lock(&tty_mutex);
1921 release_tty(tty, idx);
1922 mutex_unlock(&tty_mutex);
1923
1924 return 0;
1925}
1926
1927/**
1928 * tty_open_current_tty - get locked tty of current task
1929 * @device: device number
1930 * @filp: file pointer to tty
1931 * @return: locked tty of the current task iff @device is /dev/tty
1932 *
1933 * Performs a re-open of the current task's controlling tty.
1934 *
1935 * We cannot return driver and index like for the other nodes because
1936 * devpts will not work then. It expects inodes to be from devpts FS.
1937 */
1938static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1939{
1940 struct tty_struct *tty;
1941 int retval;
1942
1943 if (device != MKDEV(TTYAUX_MAJOR, 0))
1944 return NULL;
1945
1946 tty = get_current_tty();
1947 if (!tty)
1948 return ERR_PTR(-ENXIO);
1949
1950 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1951 /* noctty = 1; */
1952 tty_lock(tty);
1953 tty_kref_put(tty); /* safe to drop the kref now */
1954
1955 retval = tty_reopen(tty);
1956 if (retval < 0) {
1957 tty_unlock(tty);
1958 tty = ERR_PTR(retval);
1959 }
1960 return tty;
1961}
1962
1963/**
1964 * tty_lookup_driver - lookup a tty driver for a given device file
1965 * @device: device number
1966 * @filp: file pointer to tty
1967 * @noctty: set if the device should not become a controlling tty
1968 * @index: index for the device in the @return driver
1969 * @return: driver for this inode (with increased refcount)
1970 *
1971 * If @return is not erroneous, the caller is responsible to decrement the
1972 * refcount by tty_driver_kref_put.
1973 *
1974 * Locking: tty_mutex protects get_tty_driver
1975 */
1976static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1977 int *index)
1978{
1979 struct tty_driver *driver;
1980
1981 switch (device) {
1982#ifdef CONFIG_VT
1983 case MKDEV(TTY_MAJOR, 0): {
1984 extern struct tty_driver *console_driver;
1985 driver = tty_driver_kref_get(console_driver);
1986 *index = fg_console;
1987 break;
1988 }
1989#endif
1990 case MKDEV(TTYAUX_MAJOR, 1): {
1991 struct tty_driver *console_driver = console_device(index);
1992 if (console_driver) {
1993 driver = tty_driver_kref_get(console_driver);
1994 if (driver) {
1995 /* Don't let /dev/console block */
1996 filp->f_flags |= O_NONBLOCK;
1997 break;
1998 }
1999 }
2000 return ERR_PTR(-ENODEV);
2001 }
2002 default:
2003 driver = get_tty_driver(device, index);
2004 if (!driver)
2005 return ERR_PTR(-ENODEV);
2006 break;
2007 }
2008 return driver;
2009}
2010
2011/**
2012 * tty_open_by_driver - open a tty device
2013 * @device: dev_t of device to open
2014 * @inode: inode of device file
2015 * @filp: file pointer to tty
2016 *
2017 * Performs the driver lookup, checks for a reopen, or otherwise
2018 * performs the first-time tty initialization.
2019 *
2020 * Returns the locked initialized or re-opened &tty_struct
2021 *
2022 * Claims the global tty_mutex to serialize:
2023 * - concurrent first-time tty initialization
2024 * - concurrent tty driver removal w/ lookup
2025 * - concurrent tty removal from driver table
2026 */
2027static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
2028 struct file *filp)
2029{
2030 struct tty_struct *tty;
2031 struct tty_driver *driver = NULL;
2032 int index = -1;
2033 int retval;
2034
2035 mutex_lock(&tty_mutex);
2036 driver = tty_lookup_driver(device, filp, &index);
2037 if (IS_ERR(driver)) {
2038 mutex_unlock(&tty_mutex);
2039 return ERR_CAST(driver);
2040 }
2041
2042 /* check whether we're reopening an existing tty */
2043 tty = tty_driver_lookup_tty(driver, filp, index);
2044 if (IS_ERR(tty)) {
2045 mutex_unlock(&tty_mutex);
2046 goto out;
2047 }
2048
2049 if (tty) {
2050 mutex_unlock(&tty_mutex);
2051 retval = tty_lock_interruptible(tty);
2052 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2053 if (retval) {
2054 if (retval == -EINTR)
2055 retval = -ERESTARTSYS;
2056 tty = ERR_PTR(retval);
2057 goto out;
2058 }
2059 retval = tty_reopen(tty);
2060 if (retval < 0) {
2061 tty_unlock(tty);
2062 tty = ERR_PTR(retval);
2063 }
2064 } else { /* Returns with the tty_lock held for now */
2065 tty = tty_init_dev(driver, index);
2066 mutex_unlock(&tty_mutex);
2067 }
2068out:
2069 tty_driver_kref_put(driver);
2070 return tty;
2071}
2072
2073/**
2074 * tty_open - open a tty device
2075 * @inode: inode of device file
2076 * @filp: file pointer to tty
2077 *
2078 * tty_open and tty_release keep up the tty count that contains the
2079 * number of opens done on a tty. We cannot use the inode-count, as
2080 * different inodes might point to the same tty.
2081 *
2082 * Open-counting is needed for pty masters, as well as for keeping
2083 * track of serial lines: DTR is dropped when the last close happens.
2084 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2085 *
2086 * The termios state of a pty is reset on first open so that
2087 * settings don't persist across reuse.
2088 *
2089 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2090 * tty->count should protect the rest.
2091 * ->siglock protects ->signal/->sighand
2092 *
2093 * Note: the tty_unlock/lock cases without a ref are only safe due to
2094 * tty_mutex
2095 */
2096
2097static int tty_open(struct inode *inode, struct file *filp)
2098{
2099 struct tty_struct *tty;
2100 int noctty, retval;
2101 dev_t device = inode->i_rdev;
2102 unsigned saved_flags = filp->f_flags;
2103
2104 nonseekable_open(inode, filp);
2105
2106retry_open:
2107 retval = tty_alloc_file(filp);
2108 if (retval)
2109 return -ENOMEM;
2110
2111 tty = tty_open_current_tty(device, filp);
2112 if (!tty)
2113 tty = tty_open_by_driver(device, inode, filp);
2114
2115 if (IS_ERR(tty)) {
2116 tty_free_file(filp);
2117 retval = PTR_ERR(tty);
2118 if (retval != -EAGAIN || signal_pending(current))
2119 return retval;
2120 schedule();
2121 goto retry_open;
2122 }
2123
2124 tty_add_file(tty, filp);
2125
2126 check_tty_count(tty, __func__);
2127 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2128
2129 if (tty->ops->open)
2130 retval = tty->ops->open(tty, filp);
2131 else
2132 retval = -ENODEV;
2133 filp->f_flags = saved_flags;
2134
2135 if (retval) {
2136 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2137
2138 tty_unlock(tty); /* need to call tty_release without BTM */
2139 tty_release(inode, filp);
2140 if (retval != -ERESTARTSYS)
2141 return retval;
2142
2143 if (signal_pending(current))
2144 return retval;
2145
2146 schedule();
2147 /*
2148 * Need to reset f_op in case a hangup happened.
2149 */
2150 if (tty_hung_up_p(filp))
2151 filp->f_op = &tty_fops;
2152 goto retry_open;
2153 }
2154 clear_bit(TTY_HUPPED, &tty->flags);
2155
2156
2157 read_lock(&tasklist_lock);
2158 spin_lock_irq(¤t->sighand->siglock);
2159 noctty = (filp->f_flags & O_NOCTTY) ||
2160 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2161 device == MKDEV(TTYAUX_MAJOR, 1) ||
2162 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2163 tty->driver->subtype == PTY_TYPE_MASTER);
2164
2165 if (!noctty &&
2166 current->signal->leader &&
2167 !current->signal->tty &&
2168 tty->session == NULL) {
2169 /*
2170 * Don't let a process that only has write access to the tty
2171 * obtain the privileges associated with having a tty as
2172 * controlling terminal (being able to reopen it with full
2173 * access through /dev/tty, being able to perform pushback).
2174 * Many distributions set the group of all ttys to "tty" and
2175 * grant write-only access to all terminals for setgid tty
2176 * binaries, which should not imply full privileges on all ttys.
2177 *
2178 * This could theoretically break old code that performs open()
2179 * on a write-only file descriptor. In that case, it might be
2180 * necessary to also permit this if
2181 * inode_permission(inode, MAY_READ) == 0.
2182 */
2183 if (filp->f_mode & FMODE_READ)
2184 __proc_set_tty(tty);
2185 }
2186 spin_unlock_irq(¤t->sighand->siglock);
2187 read_unlock(&tasklist_lock);
2188 tty_unlock(tty);
2189 return 0;
2190}
2191
2192
2193
2194/**
2195 * tty_poll - check tty status
2196 * @filp: file being polled
2197 * @wait: poll wait structures to update
2198 *
2199 * Call the line discipline polling method to obtain the poll
2200 * status of the device.
2201 *
2202 * Locking: locks called line discipline but ldisc poll method
2203 * may be re-entered freely by other callers.
2204 */
2205
2206static unsigned int tty_poll(struct file *filp, poll_table *wait)
2207{
2208 struct tty_struct *tty = file_tty(filp);
2209 struct tty_ldisc *ld;
2210 int ret = 0;
2211
2212 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2213 return 0;
2214
2215 ld = tty_ldisc_ref_wait(tty);
2216 if (!ld)
2217 return hung_up_tty_poll(filp, wait);
2218 if (ld->ops->poll)
2219 ret = ld->ops->poll(tty, filp, wait);
2220 tty_ldisc_deref(ld);
2221 return ret;
2222}
2223
2224static int __tty_fasync(int fd, struct file *filp, int on)
2225{
2226 struct tty_struct *tty = file_tty(filp);
2227 unsigned long flags;
2228 int retval = 0;
2229
2230 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2231 goto out;
2232
2233 retval = fasync_helper(fd, filp, on, &tty->fasync);
2234 if (retval <= 0)
2235 goto out;
2236
2237 if (on) {
2238 enum pid_type type;
2239 struct pid *pid;
2240
2241 spin_lock_irqsave(&tty->ctrl_lock, flags);
2242 if (tty->pgrp) {
2243 pid = tty->pgrp;
2244 type = PIDTYPE_PGID;
2245 } else {
2246 pid = task_pid(current);
2247 type = PIDTYPE_PID;
2248 }
2249 get_pid(pid);
2250 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2251 __f_setown(filp, pid, type, 0);
2252 put_pid(pid);
2253 retval = 0;
2254 }
2255out:
2256 return retval;
2257}
2258
2259static int tty_fasync(int fd, struct file *filp, int on)
2260{
2261 struct tty_struct *tty = file_tty(filp);
2262 int retval = -ENOTTY;
2263
2264 tty_lock(tty);
2265 if (!tty_hung_up_p(filp))
2266 retval = __tty_fasync(fd, filp, on);
2267 tty_unlock(tty);
2268
2269 return retval;
2270}
2271
2272/**
2273 * tiocsti - fake input character
2274 * @tty: tty to fake input into
2275 * @p: pointer to character
2276 *
2277 * Fake input to a tty device. Does the necessary locking and
2278 * input management.
2279 *
2280 * FIXME: does not honour flow control ??
2281 *
2282 * Locking:
2283 * Called functions take tty_ldiscs_lock
2284 * current->signal->tty check is safe without locks
2285 *
2286 * FIXME: may race normal receive processing
2287 */
2288
2289static int tiocsti(struct tty_struct *tty, char __user *p)
2290{
2291 char ch, mbz = 0;
2292 struct tty_ldisc *ld;
2293
2294 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2295 return -EPERM;
2296 if (get_user(ch, p))
2297 return -EFAULT;
2298 tty_audit_tiocsti(tty, ch);
2299 ld = tty_ldisc_ref_wait(tty);
2300 if (!ld)
2301 return -EIO;
2302 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2303 tty_ldisc_deref(ld);
2304 return 0;
2305}
2306
2307/**
2308 * tiocgwinsz - implement window query ioctl
2309 * @tty; tty
2310 * @arg: user buffer for result
2311 *
2312 * Copies the kernel idea of the window size into the user buffer.
2313 *
2314 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2315 * is consistent.
2316 */
2317
2318static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2319{
2320 int err;
2321
2322 mutex_lock(&tty->winsize_mutex);
2323 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2324 mutex_unlock(&tty->winsize_mutex);
2325
2326 return err ? -EFAULT: 0;
2327}
2328
2329/**
2330 * tty_do_resize - resize event
2331 * @tty: tty being resized
2332 * @rows: rows (character)
2333 * @cols: cols (character)
2334 *
2335 * Update the termios variables and send the necessary signals to
2336 * peform a terminal resize correctly
2337 */
2338
2339int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2340{
2341 struct pid *pgrp;
2342
2343 /* Lock the tty */
2344 mutex_lock(&tty->winsize_mutex);
2345 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2346 goto done;
2347
2348 /* Signal the foreground process group */
2349 pgrp = tty_get_pgrp(tty);
2350 if (pgrp)
2351 kill_pgrp(pgrp, SIGWINCH, 1);
2352 put_pid(pgrp);
2353
2354 tty->winsize = *ws;
2355done:
2356 mutex_unlock(&tty->winsize_mutex);
2357 return 0;
2358}
2359EXPORT_SYMBOL(tty_do_resize);
2360
2361/**
2362 * tiocswinsz - implement window size set ioctl
2363 * @tty; tty side of tty
2364 * @arg: user buffer for result
2365 *
2366 * Copies the user idea of the window size to the kernel. Traditionally
2367 * this is just advisory information but for the Linux console it
2368 * actually has driver level meaning and triggers a VC resize.
2369 *
2370 * Locking:
2371 * Driver dependent. The default do_resize method takes the
2372 * tty termios mutex and ctrl_lock. The console takes its own lock
2373 * then calls into the default method.
2374 */
2375
2376static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2377{
2378 struct winsize tmp_ws;
2379 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2380 return -EFAULT;
2381
2382 if (tty->ops->resize)
2383 return tty->ops->resize(tty, &tmp_ws);
2384 else
2385 return tty_do_resize(tty, &tmp_ws);
2386}
2387
2388/**
2389 * tioccons - allow admin to move logical console
2390 * @file: the file to become console
2391 *
2392 * Allow the administrator to move the redirected console device
2393 *
2394 * Locking: uses redirect_lock to guard the redirect information
2395 */
2396
2397static int tioccons(struct file *file)
2398{
2399 if (!capable(CAP_SYS_ADMIN))
2400 return -EPERM;
2401 if (file->f_op->write == redirected_tty_write) {
2402 struct file *f;
2403 spin_lock(&redirect_lock);
2404 f = redirect;
2405 redirect = NULL;
2406 spin_unlock(&redirect_lock);
2407 if (f)
2408 fput(f);
2409 return 0;
2410 }
2411 spin_lock(&redirect_lock);
2412 if (redirect) {
2413 spin_unlock(&redirect_lock);
2414 return -EBUSY;
2415 }
2416 redirect = get_file(file);
2417 spin_unlock(&redirect_lock);
2418 return 0;
2419}
2420
2421/**
2422 * fionbio - non blocking ioctl
2423 * @file: file to set blocking value
2424 * @p: user parameter
2425 *
2426 * Historical tty interfaces had a blocking control ioctl before
2427 * the generic functionality existed. This piece of history is preserved
2428 * in the expected tty API of posix OS's.
2429 *
2430 * Locking: none, the open file handle ensures it won't go away.
2431 */
2432
2433static int fionbio(struct file *file, int __user *p)
2434{
2435 int nonblock;
2436
2437 if (get_user(nonblock, p))
2438 return -EFAULT;
2439
2440 spin_lock(&file->f_lock);
2441 if (nonblock)
2442 file->f_flags |= O_NONBLOCK;
2443 else
2444 file->f_flags &= ~O_NONBLOCK;
2445 spin_unlock(&file->f_lock);
2446 return 0;
2447}
2448
2449/**
2450 * tiocsctty - set controlling tty
2451 * @tty: tty structure
2452 * @arg: user argument
2453 *
2454 * This ioctl is used to manage job control. It permits a session
2455 * leader to set this tty as the controlling tty for the session.
2456 *
2457 * Locking:
2458 * Takes tty_lock() to serialize proc_set_tty() for this tty
2459 * Takes tasklist_lock internally to walk sessions
2460 * Takes ->siglock() when updating signal->tty
2461 */
2462
2463static int tiocsctty(struct tty_struct *tty, struct file *file, int arg)
2464{
2465 int ret = 0;
2466
2467 tty_lock(tty);
2468 read_lock(&tasklist_lock);
2469
2470 if (current->signal->leader && (task_session(current) == tty->session))
2471 goto unlock;
2472
2473 /*
2474 * The process must be a session leader and
2475 * not have a controlling tty already.
2476 */
2477 if (!current->signal->leader || current->signal->tty) {
2478 ret = -EPERM;
2479 goto unlock;
2480 }
2481
2482 if (tty->session) {
2483 /*
2484 * This tty is already the controlling
2485 * tty for another session group!
2486 */
2487 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2488 /*
2489 * Steal it away
2490 */
2491 session_clear_tty(tty->session);
2492 } else {
2493 ret = -EPERM;
2494 goto unlock;
2495 }
2496 }
2497
2498 /* See the comment in tty_open(). */
2499 if ((file->f_mode & FMODE_READ) == 0 && !capable(CAP_SYS_ADMIN)) {
2500 ret = -EPERM;
2501 goto unlock;
2502 }
2503
2504 proc_set_tty(tty);
2505unlock:
2506 read_unlock(&tasklist_lock);
2507 tty_unlock(tty);
2508 return ret;
2509}
2510
2511/**
2512 * tty_get_pgrp - return a ref counted pgrp pid
2513 * @tty: tty to read
2514 *
2515 * Returns a refcounted instance of the pid struct for the process
2516 * group controlling the tty.
2517 */
2518
2519struct pid *tty_get_pgrp(struct tty_struct *tty)
2520{
2521 unsigned long flags;
2522 struct pid *pgrp;
2523
2524 spin_lock_irqsave(&tty->ctrl_lock, flags);
2525 pgrp = get_pid(tty->pgrp);
2526 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2527
2528 return pgrp;
2529}
2530EXPORT_SYMBOL_GPL(tty_get_pgrp);
2531
2532/*
2533 * This checks not only the pgrp, but falls back on the pid if no
2534 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
2535 * without this...
2536 *
2537 * The caller must hold rcu lock or the tasklist lock.
2538 */
2539static struct pid *session_of_pgrp(struct pid *pgrp)
2540{
2541 struct task_struct *p;
2542 struct pid *sid = NULL;
2543
2544 p = pid_task(pgrp, PIDTYPE_PGID);
2545 if (p == NULL)
2546 p = pid_task(pgrp, PIDTYPE_PID);
2547 if (p != NULL)
2548 sid = task_session(p);
2549
2550 return sid;
2551}
2552
2553/**
2554 * tiocgpgrp - get process group
2555 * @tty: tty passed by user
2556 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2557 * @p: returned pid
2558 *
2559 * Obtain the process group of the tty. If there is no process group
2560 * return an error.
2561 *
2562 * Locking: none. Reference to current->signal->tty is safe.
2563 */
2564
2565static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2566{
2567 struct pid *pid;
2568 int ret;
2569 /*
2570 * (tty == real_tty) is a cheap way of
2571 * testing if the tty is NOT a master pty.
2572 */
2573 if (tty == real_tty && current->signal->tty != real_tty)
2574 return -ENOTTY;
2575 pid = tty_get_pgrp(real_tty);
2576 ret = put_user(pid_vnr(pid), p);
2577 put_pid(pid);
2578 return ret;
2579}
2580
2581/**
2582 * tiocspgrp - attempt to set process group
2583 * @tty: tty passed by user
2584 * @real_tty: tty side device matching tty passed by user
2585 * @p: pid pointer
2586 *
2587 * Set the process group of the tty to the session passed. Only
2588 * permitted where the tty session is our session.
2589 *
2590 * Locking: RCU, ctrl lock
2591 */
2592
2593static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2594{
2595 struct pid *pgrp;
2596 pid_t pgrp_nr;
2597 int retval = tty_check_change(real_tty);
2598
2599 if (retval == -EIO)
2600 return -ENOTTY;
2601 if (retval)
2602 return retval;
2603 if (!current->signal->tty ||
2604 (current->signal->tty != real_tty) ||
2605 (real_tty->session != task_session(current)))
2606 return -ENOTTY;
2607 if (get_user(pgrp_nr, p))
2608 return -EFAULT;
2609 if (pgrp_nr < 0)
2610 return -EINVAL;
2611 rcu_read_lock();
2612 pgrp = find_vpid(pgrp_nr);
2613 retval = -ESRCH;
2614 if (!pgrp)
2615 goto out_unlock;
2616 retval = -EPERM;
2617 if (session_of_pgrp(pgrp) != task_session(current))
2618 goto out_unlock;
2619 retval = 0;
2620 spin_lock_irq(&tty->ctrl_lock);
2621 put_pid(real_tty->pgrp);
2622 real_tty->pgrp = get_pid(pgrp);
2623 spin_unlock_irq(&tty->ctrl_lock);
2624out_unlock:
2625 rcu_read_unlock();
2626 return retval;
2627}
2628
2629/**
2630 * tiocgsid - get session id
2631 * @tty: tty passed by user
2632 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2633 * @p: pointer to returned session id
2634 *
2635 * Obtain the session id of the tty. If there is no session
2636 * return an error.
2637 *
2638 * Locking: none. Reference to current->signal->tty is safe.
2639 */
2640
2641static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2642{
2643 /*
2644 * (tty == real_tty) is a cheap way of
2645 * testing if the tty is NOT a master pty.
2646 */
2647 if (tty == real_tty && current->signal->tty != real_tty)
2648 return -ENOTTY;
2649 if (!real_tty->session)
2650 return -ENOTTY;
2651 return put_user(pid_vnr(real_tty->session), p);
2652}
2653
2654/**
2655 * tiocsetd - set line discipline
2656 * @tty: tty device
2657 * @p: pointer to user data
2658 *
2659 * Set the line discipline according to user request.
2660 *
2661 * Locking: see tty_set_ldisc, this function is just a helper
2662 */
2663
2664static int tiocsetd(struct tty_struct *tty, int __user *p)
2665{
2666 int disc;
2667 int ret;
2668
2669 if (get_user(disc, p))
2670 return -EFAULT;
2671
2672 ret = tty_set_ldisc(tty, disc);
2673
2674 return ret;
2675}
2676
2677/**
2678 * tiocgetd - get line discipline
2679 * @tty: tty device
2680 * @p: pointer to user data
2681 *
2682 * Retrieves the line discipline id directly from the ldisc.
2683 *
2684 * Locking: waits for ldisc reference (in case the line discipline
2685 * is changing or the tty is being hungup)
2686 */
2687
2688static int tiocgetd(struct tty_struct *tty, int __user *p)
2689{
2690 struct tty_ldisc *ld;
2691 int ret;
2692
2693 ld = tty_ldisc_ref_wait(tty);
2694 if (!ld)
2695 return -EIO;
2696 ret = put_user(ld->ops->num, p);
2697 tty_ldisc_deref(ld);
2698 return ret;
2699}
2700
2701/**
2702 * send_break - performed time break
2703 * @tty: device to break on
2704 * @duration: timeout in mS
2705 *
2706 * Perform a timed break on hardware that lacks its own driver level
2707 * timed break functionality.
2708 *
2709 * Locking:
2710 * atomic_write_lock serializes
2711 *
2712 */
2713
2714static int send_break(struct tty_struct *tty, unsigned int duration)
2715{
2716 int retval;
2717
2718 if (tty->ops->break_ctl == NULL)
2719 return 0;
2720
2721 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2722 retval = tty->ops->break_ctl(tty, duration);
2723 else {
2724 /* Do the work ourselves */
2725 if (tty_write_lock(tty, 0) < 0)
2726 return -EINTR;
2727 retval = tty->ops->break_ctl(tty, -1);
2728 if (retval)
2729 goto out;
2730 if (!signal_pending(current))
2731 msleep_interruptible(duration);
2732 retval = tty->ops->break_ctl(tty, 0);
2733out:
2734 tty_write_unlock(tty);
2735 if (signal_pending(current))
2736 retval = -EINTR;
2737 }
2738 return retval;
2739}
2740
2741/**
2742 * tty_tiocmget - get modem status
2743 * @tty: tty device
2744 * @file: user file pointer
2745 * @p: pointer to result
2746 *
2747 * Obtain the modem status bits from the tty driver if the feature
2748 * is supported. Return -EINVAL if it is not available.
2749 *
2750 * Locking: none (up to the driver)
2751 */
2752
2753static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2754{
2755 int retval = -EINVAL;
2756
2757 if (tty->ops->tiocmget) {
2758 retval = tty->ops->tiocmget(tty);
2759
2760 if (retval >= 0)
2761 retval = put_user(retval, p);
2762 }
2763 return retval;
2764}
2765
2766/**
2767 * tty_tiocmset - set modem status
2768 * @tty: tty device
2769 * @cmd: command - clear bits, set bits or set all
2770 * @p: pointer to desired bits
2771 *
2772 * Set the modem status bits from the tty driver if the feature
2773 * is supported. Return -EINVAL if it is not available.
2774 *
2775 * Locking: none (up to the driver)
2776 */
2777
2778static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2779 unsigned __user *p)
2780{
2781 int retval;
2782 unsigned int set, clear, val;
2783
2784 if (tty->ops->tiocmset == NULL)
2785 return -EINVAL;
2786
2787 retval = get_user(val, p);
2788 if (retval)
2789 return retval;
2790 set = clear = 0;
2791 switch (cmd) {
2792 case TIOCMBIS:
2793 set = val;
2794 break;
2795 case TIOCMBIC:
2796 clear = val;
2797 break;
2798 case TIOCMSET:
2799 set = val;
2800 clear = ~val;
2801 break;
2802 }
2803 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2804 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2805 return tty->ops->tiocmset(tty, set, clear);
2806}
2807
2808static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2809{
2810 int retval = -EINVAL;
2811 struct serial_icounter_struct icount;
2812 memset(&icount, 0, sizeof(icount));
2813 if (tty->ops->get_icount)
2814 retval = tty->ops->get_icount(tty, &icount);
2815 if (retval != 0)
2816 return retval;
2817 if (copy_to_user(arg, &icount, sizeof(icount)))
2818 return -EFAULT;
2819 return 0;
2820}
2821
2822static void tty_warn_deprecated_flags(struct serial_struct __user *ss)
2823{
2824 static DEFINE_RATELIMIT_STATE(depr_flags,
2825 DEFAULT_RATELIMIT_INTERVAL,
2826 DEFAULT_RATELIMIT_BURST);
2827 char comm[TASK_COMM_LEN];
2828 int flags;
2829
2830 if (get_user(flags, &ss->flags))
2831 return;
2832
2833 flags &= ASYNC_DEPRECATED;
2834
2835 if (flags && __ratelimit(&depr_flags))
2836 pr_warning("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2837 __func__, get_task_comm(comm, current), flags);
2838}
2839
2840/*
2841 * if pty, return the slave side (real_tty)
2842 * otherwise, return self
2843 */
2844static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2845{
2846 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2847 tty->driver->subtype == PTY_TYPE_MASTER)
2848 tty = tty->link;
2849 return tty;
2850}
2851
2852/*
2853 * Split this up, as gcc can choke on it otherwise..
2854 */
2855long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2856{
2857 struct tty_struct *tty = file_tty(file);
2858 struct tty_struct *real_tty;
2859 void __user *p = (void __user *)arg;
2860 int retval;
2861 struct tty_ldisc *ld;
2862
2863 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2864 return -EINVAL;
2865
2866 real_tty = tty_pair_get_tty(tty);
2867
2868 /*
2869 * Factor out some common prep work
2870 */
2871 switch (cmd) {
2872 case TIOCSETD:
2873 case TIOCSBRK:
2874 case TIOCCBRK:
2875 case TCSBRK:
2876 case TCSBRKP:
2877 retval = tty_check_change(tty);
2878 if (retval)
2879 return retval;
2880 if (cmd != TIOCCBRK) {
2881 tty_wait_until_sent(tty, 0);
2882 if (signal_pending(current))
2883 return -EINTR;
2884 }
2885 break;
2886 }
2887
2888 /*
2889 * Now do the stuff.
2890 */
2891 switch (cmd) {
2892 case TIOCSTI:
2893 return tiocsti(tty, p);
2894 case TIOCGWINSZ:
2895 return tiocgwinsz(real_tty, p);
2896 case TIOCSWINSZ:
2897 return tiocswinsz(real_tty, p);
2898 case TIOCCONS:
2899 return real_tty != tty ? -EINVAL : tioccons(file);
2900 case FIONBIO:
2901 return fionbio(file, p);
2902 case TIOCEXCL:
2903 set_bit(TTY_EXCLUSIVE, &tty->flags);
2904 return 0;
2905 case TIOCNXCL:
2906 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2907 return 0;
2908 case TIOCGEXCL:
2909 {
2910 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2911 return put_user(excl, (int __user *)p);
2912 }
2913 case TIOCNOTTY:
2914 if (current->signal->tty != tty)
2915 return -ENOTTY;
2916 no_tty();
2917 return 0;
2918 case TIOCSCTTY:
2919 return tiocsctty(real_tty, file, arg);
2920 case TIOCGPGRP:
2921 return tiocgpgrp(tty, real_tty, p);
2922 case TIOCSPGRP:
2923 return tiocspgrp(tty, real_tty, p);
2924 case TIOCGSID:
2925 return tiocgsid(tty, real_tty, p);
2926 case TIOCGETD:
2927 return tiocgetd(tty, p);
2928 case TIOCSETD:
2929 return tiocsetd(tty, p);
2930 case TIOCVHANGUP:
2931 if (!capable(CAP_SYS_ADMIN))
2932 return -EPERM;
2933 tty_vhangup(tty);
2934 return 0;
2935 case TIOCGDEV:
2936 {
2937 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2938 return put_user(ret, (unsigned int __user *)p);
2939 }
2940 /*
2941 * Break handling
2942 */
2943 case TIOCSBRK: /* Turn break on, unconditionally */
2944 if (tty->ops->break_ctl)
2945 return tty->ops->break_ctl(tty, -1);
2946 return 0;
2947 case TIOCCBRK: /* Turn break off, unconditionally */
2948 if (tty->ops->break_ctl)
2949 return tty->ops->break_ctl(tty, 0);
2950 return 0;
2951 case TCSBRK: /* SVID version: non-zero arg --> no break */
2952 /* non-zero arg means wait for all output data
2953 * to be sent (performed above) but don't send break.
2954 * This is used by the tcdrain() termios function.
2955 */
2956 if (!arg)
2957 return send_break(tty, 250);
2958 return 0;
2959 case TCSBRKP: /* support for POSIX tcsendbreak() */
2960 return send_break(tty, arg ? arg*100 : 250);
2961
2962 case TIOCMGET:
2963 return tty_tiocmget(tty, p);
2964 case TIOCMSET:
2965 case TIOCMBIC:
2966 case TIOCMBIS:
2967 return tty_tiocmset(tty, cmd, p);
2968 case TIOCGICOUNT:
2969 retval = tty_tiocgicount(tty, p);
2970 /* For the moment allow fall through to the old method */
2971 if (retval != -EINVAL)
2972 return retval;
2973 break;
2974 case TCFLSH:
2975 switch (arg) {
2976 case TCIFLUSH:
2977 case TCIOFLUSH:
2978 /* flush tty buffer and allow ldisc to process ioctl */
2979 tty_buffer_flush(tty, NULL);
2980 break;
2981 }
2982 break;
2983 case TIOCSSERIAL:
2984 tty_warn_deprecated_flags(p);
2985 break;
2986 }
2987 if (tty->ops->ioctl) {
2988 retval = tty->ops->ioctl(tty, cmd, arg);
2989 if (retval != -ENOIOCTLCMD)
2990 return retval;
2991 }
2992 ld = tty_ldisc_ref_wait(tty);
2993 if (!ld)
2994 return hung_up_tty_ioctl(file, cmd, arg);
2995 retval = -EINVAL;
2996 if (ld->ops->ioctl) {
2997 retval = ld->ops->ioctl(tty, file, cmd, arg);
2998 if (retval == -ENOIOCTLCMD)
2999 retval = -ENOTTY;
3000 }
3001 tty_ldisc_deref(ld);
3002 return retval;
3003}
3004
3005#ifdef CONFIG_COMPAT
3006static long tty_compat_ioctl(struct file *file, unsigned int cmd,
3007 unsigned long arg)
3008{
3009 struct tty_struct *tty = file_tty(file);
3010 struct tty_ldisc *ld;
3011 int retval = -ENOIOCTLCMD;
3012
3013 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
3014 return -EINVAL;
3015
3016 if (tty->ops->compat_ioctl) {
3017 retval = tty->ops->compat_ioctl(tty, cmd, arg);
3018 if (retval != -ENOIOCTLCMD)
3019 return retval;
3020 }
3021
3022 ld = tty_ldisc_ref_wait(tty);
3023 if (!ld)
3024 return hung_up_tty_compat_ioctl(file, cmd, arg);
3025 if (ld->ops->compat_ioctl)
3026 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
3027 else
3028 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
3029 tty_ldisc_deref(ld);
3030
3031 return retval;
3032}
3033#endif
3034
3035static int this_tty(const void *t, struct file *file, unsigned fd)
3036{
3037 if (likely(file->f_op->read != tty_read))
3038 return 0;
3039 return file_tty(file) != t ? 0 : fd + 1;
3040}
3041
3042/*
3043 * This implements the "Secure Attention Key" --- the idea is to
3044 * prevent trojan horses by killing all processes associated with this
3045 * tty when the user hits the "Secure Attention Key". Required for
3046 * super-paranoid applications --- see the Orange Book for more details.
3047 *
3048 * This code could be nicer; ideally it should send a HUP, wait a few
3049 * seconds, then send a INT, and then a KILL signal. But you then
3050 * have to coordinate with the init process, since all processes associated
3051 * with the current tty must be dead before the new getty is allowed
3052 * to spawn.
3053 *
3054 * Now, if it would be correct ;-/ The current code has a nasty hole -
3055 * it doesn't catch files in flight. We may send the descriptor to ourselves
3056 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3057 *
3058 * Nasty bug: do_SAK is being called in interrupt context. This can
3059 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3060 */
3061void __do_SAK(struct tty_struct *tty)
3062{
3063#ifdef TTY_SOFT_SAK
3064 tty_hangup(tty);
3065#else
3066 struct task_struct *g, *p;
3067 struct pid *session;
3068 int i;
3069
3070 if (!tty)
3071 return;
3072 session = tty->session;
3073
3074 tty_ldisc_flush(tty);
3075
3076 tty_driver_flush_buffer(tty);
3077
3078 read_lock(&tasklist_lock);
3079 /* Kill the entire session */
3080 do_each_pid_task(session, PIDTYPE_SID, p) {
3081 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3082 task_pid_nr(p), p->comm);
3083 send_sig(SIGKILL, p, 1);
3084 } while_each_pid_task(session, PIDTYPE_SID, p);
3085
3086 /* Now kill any processes that happen to have the tty open */
3087 do_each_thread(g, p) {
3088 if (p->signal->tty == tty) {
3089 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3090 task_pid_nr(p), p->comm);
3091 send_sig(SIGKILL, p, 1);
3092 continue;
3093 }
3094 task_lock(p);
3095 i = iterate_fd(p->files, 0, this_tty, tty);
3096 if (i != 0) {
3097 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3098 task_pid_nr(p), p->comm, i - 1);
3099 force_sig(SIGKILL, p);
3100 }
3101 task_unlock(p);
3102 } while_each_thread(g, p);
3103 read_unlock(&tasklist_lock);
3104#endif
3105}
3106
3107static void do_SAK_work(struct work_struct *work)
3108{
3109 struct tty_struct *tty =
3110 container_of(work, struct tty_struct, SAK_work);
3111 __do_SAK(tty);
3112}
3113
3114/*
3115 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3116 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3117 * the values which we write to it will be identical to the values which it
3118 * already has. --akpm
3119 */
3120void do_SAK(struct tty_struct *tty)
3121{
3122 if (!tty)
3123 return;
3124 schedule_work(&tty->SAK_work);
3125}
3126
3127EXPORT_SYMBOL(do_SAK);
3128
3129static int dev_match_devt(struct device *dev, const void *data)
3130{
3131 const dev_t *devt = data;
3132 return dev->devt == *devt;
3133}
3134
3135/* Must put_device() after it's unused! */
3136static struct device *tty_get_device(struct tty_struct *tty)
3137{
3138 dev_t devt = tty_devnum(tty);
3139 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
3140}
3141
3142
3143/**
3144 * alloc_tty_struct
3145 *
3146 * This subroutine allocates and initializes a tty structure.
3147 *
3148 * Locking: none - tty in question is not exposed at this point
3149 */
3150
3151struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3152{
3153 struct tty_struct *tty;
3154
3155 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
3156 if (!tty)
3157 return NULL;
3158
3159 kref_init(&tty->kref);
3160 tty->magic = TTY_MAGIC;
3161 tty_ldisc_init(tty);
3162 tty->session = NULL;
3163 tty->pgrp = NULL;
3164 mutex_init(&tty->legacy_mutex);
3165 mutex_init(&tty->throttle_mutex);
3166 init_rwsem(&tty->termios_rwsem);
3167 mutex_init(&tty->winsize_mutex);
3168 init_ldsem(&tty->ldisc_sem);
3169 init_waitqueue_head(&tty->write_wait);
3170 init_waitqueue_head(&tty->read_wait);
3171 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3172 mutex_init(&tty->atomic_write_lock);
3173 spin_lock_init(&tty->ctrl_lock);
3174 spin_lock_init(&tty->flow_lock);
3175 spin_lock_init(&tty->files_lock);
3176 INIT_LIST_HEAD(&tty->tty_files);
3177 INIT_WORK(&tty->SAK_work, do_SAK_work);
3178
3179 tty->driver = driver;
3180 tty->ops = driver->ops;
3181 tty->index = idx;
3182 tty_line_name(driver, idx, tty->name);
3183 tty->dev = tty_get_device(tty);
3184
3185 return tty;
3186}
3187
3188/**
3189 * tty_put_char - write one character to a tty
3190 * @tty: tty
3191 * @ch: character
3192 *
3193 * Write one byte to the tty using the provided put_char method
3194 * if present. Returns the number of characters successfully output.
3195 *
3196 * Note: the specific put_char operation in the driver layer may go
3197 * away soon. Don't call it directly, use this method
3198 */
3199
3200int tty_put_char(struct tty_struct *tty, unsigned char ch)
3201{
3202 if (tty->ops->put_char)
3203 return tty->ops->put_char(tty, ch);
3204 return tty->ops->write(tty, &ch, 1);
3205}
3206EXPORT_SYMBOL_GPL(tty_put_char);
3207
3208struct class *tty_class;
3209
3210static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3211 unsigned int index, unsigned int count)
3212{
3213 int err;
3214
3215 /* init here, since reused cdevs cause crashes */
3216 driver->cdevs[index] = cdev_alloc();
3217 if (!driver->cdevs[index])
3218 return -ENOMEM;
3219 driver->cdevs[index]->ops = &tty_fops;
3220 driver->cdevs[index]->owner = driver->owner;
3221 err = cdev_add(driver->cdevs[index], dev, count);
3222 if (err)
3223 kobject_put(&driver->cdevs[index]->kobj);
3224 return err;
3225}
3226
3227/**
3228 * tty_register_device - register a tty device
3229 * @driver: the tty driver that describes the tty device
3230 * @index: the index in the tty driver for this tty device
3231 * @device: a struct device that is associated with this tty device.
3232 * This field is optional, if there is no known struct device
3233 * for this tty device it can be set to NULL safely.
3234 *
3235 * Returns a pointer to the struct device for this tty device
3236 * (or ERR_PTR(-EFOO) on error).
3237 *
3238 * This call is required to be made to register an individual tty device
3239 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3240 * that bit is not set, this function should not be called by a tty
3241 * driver.
3242 *
3243 * Locking: ??
3244 */
3245
3246struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3247 struct device *device)
3248{
3249 return tty_register_device_attr(driver, index, device, NULL, NULL);
3250}
3251EXPORT_SYMBOL(tty_register_device);
3252
3253static void tty_device_create_release(struct device *dev)
3254{
3255 dev_dbg(dev, "releasing...\n");
3256 kfree(dev);
3257}
3258
3259/**
3260 * tty_register_device_attr - register a tty device
3261 * @driver: the tty driver that describes the tty device
3262 * @index: the index in the tty driver for this tty device
3263 * @device: a struct device that is associated with this tty device.
3264 * This field is optional, if there is no known struct device
3265 * for this tty device it can be set to NULL safely.
3266 * @drvdata: Driver data to be set to device.
3267 * @attr_grp: Attribute group to be set on device.
3268 *
3269 * Returns a pointer to the struct device for this tty device
3270 * (or ERR_PTR(-EFOO) on error).
3271 *
3272 * This call is required to be made to register an individual tty device
3273 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3274 * that bit is not set, this function should not be called by a tty
3275 * driver.
3276 *
3277 * Locking: ??
3278 */
3279struct device *tty_register_device_attr(struct tty_driver *driver,
3280 unsigned index, struct device *device,
3281 void *drvdata,
3282 const struct attribute_group **attr_grp)
3283{
3284 char name[64];
3285 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3286 struct device *dev = NULL;
3287 int retval = -ENODEV;
3288 bool cdev = false;
3289
3290 if (index >= driver->num) {
3291 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3292 driver->name, index);
3293 return ERR_PTR(-EINVAL);
3294 }
3295
3296 if (driver->type == TTY_DRIVER_TYPE_PTY)
3297 pty_line_name(driver, index, name);
3298 else
3299 tty_line_name(driver, index, name);
3300
3301 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3302 retval = tty_cdev_add(driver, devt, index, 1);
3303 if (retval)
3304 goto error;
3305 cdev = true;
3306 }
3307
3308 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3309 if (!dev) {
3310 retval = -ENOMEM;
3311 goto error;
3312 }
3313
3314 dev->devt = devt;
3315 dev->class = tty_class;
3316 dev->parent = device;
3317 dev->release = tty_device_create_release;
3318 dev_set_name(dev, "%s", name);
3319 dev->groups = attr_grp;
3320 dev_set_drvdata(dev, drvdata);
3321
3322 retval = device_register(dev);
3323 if (retval)
3324 goto error;
3325
3326 return dev;
3327
3328error:
3329 put_device(dev);
3330 if (cdev) {
3331 cdev_del(driver->cdevs[index]);
3332 driver->cdevs[index] = NULL;
3333 }
3334 return ERR_PTR(retval);
3335}
3336EXPORT_SYMBOL_GPL(tty_register_device_attr);
3337
3338/**
3339 * tty_unregister_device - unregister a tty device
3340 * @driver: the tty driver that describes the tty device
3341 * @index: the index in the tty driver for this tty device
3342 *
3343 * If a tty device is registered with a call to tty_register_device() then
3344 * this function must be called when the tty device is gone.
3345 *
3346 * Locking: ??
3347 */
3348
3349void tty_unregister_device(struct tty_driver *driver, unsigned index)
3350{
3351 device_destroy(tty_class,
3352 MKDEV(driver->major, driver->minor_start) + index);
3353 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3354 cdev_del(driver->cdevs[index]);
3355 driver->cdevs[index] = NULL;
3356 }
3357}
3358EXPORT_SYMBOL(tty_unregister_device);
3359
3360/**
3361 * __tty_alloc_driver -- allocate tty driver
3362 * @lines: count of lines this driver can handle at most
3363 * @owner: module which is repsonsible for this driver
3364 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3365 *
3366 * This should not be called directly, some of the provided macros should be
3367 * used instead. Use IS_ERR and friends on @retval.
3368 */
3369struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3370 unsigned long flags)
3371{
3372 struct tty_driver *driver;
3373 unsigned int cdevs = 1;
3374 int err;
3375
3376 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3377 return ERR_PTR(-EINVAL);
3378
3379 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3380 if (!driver)
3381 return ERR_PTR(-ENOMEM);
3382
3383 kref_init(&driver->kref);
3384 driver->magic = TTY_DRIVER_MAGIC;
3385 driver->num = lines;
3386 driver->owner = owner;
3387 driver->flags = flags;
3388
3389 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3390 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3391 GFP_KERNEL);
3392 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3393 GFP_KERNEL);
3394 if (!driver->ttys || !driver->termios) {
3395 err = -ENOMEM;
3396 goto err_free_all;
3397 }
3398 }
3399
3400 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3401 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3402 GFP_KERNEL);
3403 if (!driver->ports) {
3404 err = -ENOMEM;
3405 goto err_free_all;
3406 }
3407 cdevs = lines;
3408 }
3409
3410 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3411 if (!driver->cdevs) {
3412 err = -ENOMEM;
3413 goto err_free_all;
3414 }
3415
3416 return driver;
3417err_free_all:
3418 kfree(driver->ports);
3419 kfree(driver->ttys);
3420 kfree(driver->termios);
3421 kfree(driver->cdevs);
3422 kfree(driver);
3423 return ERR_PTR(err);
3424}
3425EXPORT_SYMBOL(__tty_alloc_driver);
3426
3427static void destruct_tty_driver(struct kref *kref)
3428{
3429 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3430 int i;
3431 struct ktermios *tp;
3432
3433 if (driver->flags & TTY_DRIVER_INSTALLED) {
3434 /*
3435 * Free the termios and termios_locked structures because
3436 * we don't want to get memory leaks when modular tty
3437 * drivers are removed from the kernel.
3438 */
3439 for (i = 0; i < driver->num; i++) {
3440 tp = driver->termios[i];
3441 if (tp) {
3442 driver->termios[i] = NULL;
3443 kfree(tp);
3444 }
3445 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3446 tty_unregister_device(driver, i);
3447 }
3448 proc_tty_unregister_driver(driver);
3449 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3450 cdev_del(driver->cdevs[0]);
3451 }
3452 kfree(driver->cdevs);
3453 kfree(driver->ports);
3454 kfree(driver->termios);
3455 kfree(driver->ttys);
3456 kfree(driver);
3457}
3458
3459void tty_driver_kref_put(struct tty_driver *driver)
3460{
3461 kref_put(&driver->kref, destruct_tty_driver);
3462}
3463EXPORT_SYMBOL(tty_driver_kref_put);
3464
3465void tty_set_operations(struct tty_driver *driver,
3466 const struct tty_operations *op)
3467{
3468 driver->ops = op;
3469};
3470EXPORT_SYMBOL(tty_set_operations);
3471
3472void put_tty_driver(struct tty_driver *d)
3473{
3474 tty_driver_kref_put(d);
3475}
3476EXPORT_SYMBOL(put_tty_driver);
3477
3478/*
3479 * Called by a tty driver to register itself.
3480 */
3481int tty_register_driver(struct tty_driver *driver)
3482{
3483 int error;
3484 int i;
3485 dev_t dev;
3486 struct device *d;
3487
3488 if (!driver->major) {
3489 error = alloc_chrdev_region(&dev, driver->minor_start,
3490 driver->num, driver->name);
3491 if (!error) {
3492 driver->major = MAJOR(dev);
3493 driver->minor_start = MINOR(dev);
3494 }
3495 } else {
3496 dev = MKDEV(driver->major, driver->minor_start);
3497 error = register_chrdev_region(dev, driver->num, driver->name);
3498 }
3499 if (error < 0)
3500 goto err;
3501
3502 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3503 error = tty_cdev_add(driver, dev, 0, driver->num);
3504 if (error)
3505 goto err_unreg_char;
3506 }
3507
3508 mutex_lock(&tty_mutex);
3509 list_add(&driver->tty_drivers, &tty_drivers);
3510 mutex_unlock(&tty_mutex);
3511
3512 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3513 for (i = 0; i < driver->num; i++) {
3514 d = tty_register_device(driver, i, NULL);
3515 if (IS_ERR(d)) {
3516 error = PTR_ERR(d);
3517 goto err_unreg_devs;
3518 }
3519 }
3520 }
3521 proc_tty_register_driver(driver);
3522 driver->flags |= TTY_DRIVER_INSTALLED;
3523 return 0;
3524
3525err_unreg_devs:
3526 for (i--; i >= 0; i--)
3527 tty_unregister_device(driver, i);
3528
3529 mutex_lock(&tty_mutex);
3530 list_del(&driver->tty_drivers);
3531 mutex_unlock(&tty_mutex);
3532
3533err_unreg_char:
3534 unregister_chrdev_region(dev, driver->num);
3535err:
3536 return error;
3537}
3538EXPORT_SYMBOL(tty_register_driver);
3539
3540/*
3541 * Called by a tty driver to unregister itself.
3542 */
3543int tty_unregister_driver(struct tty_driver *driver)
3544{
3545#if 0
3546 /* FIXME */
3547 if (driver->refcount)
3548 return -EBUSY;
3549#endif
3550 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3551 driver->num);
3552 mutex_lock(&tty_mutex);
3553 list_del(&driver->tty_drivers);
3554 mutex_unlock(&tty_mutex);
3555 return 0;
3556}
3557
3558EXPORT_SYMBOL(tty_unregister_driver);
3559
3560dev_t tty_devnum(struct tty_struct *tty)
3561{
3562 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3563}
3564EXPORT_SYMBOL(tty_devnum);
3565
3566void tty_default_fops(struct file_operations *fops)
3567{
3568 *fops = tty_fops;
3569}
3570
3571/*
3572 * Initialize the console device. This is called *early*, so
3573 * we can't necessarily depend on lots of kernel help here.
3574 * Just do some early initializations, and do the complex setup
3575 * later.
3576 */
3577void __init console_init(void)
3578{
3579 initcall_t *call;
3580
3581 /* Setup the default TTY line discipline. */
3582 n_tty_init();
3583
3584 /*
3585 * set up the console device so that later boot sequences can
3586 * inform about problems etc..
3587 */
3588 call = __con_initcall_start;
3589 while (call < __con_initcall_end) {
3590 (*call)();
3591 call++;
3592 }
3593}
3594
3595static char *tty_devnode(struct device *dev, umode_t *mode)
3596{
3597 if (!mode)
3598 return NULL;
3599 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3600 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3601 *mode = 0666;
3602 return NULL;
3603}
3604
3605static int __init tty_class_init(void)
3606{
3607 tty_class = class_create(THIS_MODULE, "tty");
3608 if (IS_ERR(tty_class))
3609 return PTR_ERR(tty_class);
3610 tty_class->devnode = tty_devnode;
3611 return 0;
3612}
3613
3614postcore_initcall(tty_class_init);
3615
3616/* 3/2004 jmc: why do these devices exist? */
3617static struct cdev tty_cdev, console_cdev;
3618
3619static ssize_t show_cons_active(struct device *dev,
3620 struct device_attribute *attr, char *buf)
3621{
3622 struct console *cs[16];
3623 int i = 0;
3624 struct console *c;
3625 ssize_t count = 0;
3626
3627 console_lock();
3628 for_each_console(c) {
3629 if (!c->device)
3630 continue;
3631 if (!c->write)
3632 continue;
3633 if ((c->flags & CON_ENABLED) == 0)
3634 continue;
3635 cs[i++] = c;
3636 if (i >= ARRAY_SIZE(cs))
3637 break;
3638 }
3639 while (i--) {
3640 int index = cs[i]->index;
3641 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3642
3643 /* don't resolve tty0 as some programs depend on it */
3644 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3645 count += tty_line_name(drv, index, buf + count);
3646 else
3647 count += sprintf(buf + count, "%s%d",
3648 cs[i]->name, cs[i]->index);
3649
3650 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3651 }
3652 console_unlock();
3653
3654 return count;
3655}
3656static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3657
3658static struct attribute *cons_dev_attrs[] = {
3659 &dev_attr_active.attr,
3660 NULL
3661};
3662
3663ATTRIBUTE_GROUPS(cons_dev);
3664
3665static struct device *consdev;
3666
3667void console_sysfs_notify(void)
3668{
3669 if (consdev)
3670 sysfs_notify(&consdev->kobj, NULL, "active");
3671}
3672
3673/*
3674 * Ok, now we can initialize the rest of the tty devices and can count
3675 * on memory allocations, interrupts etc..
3676 */
3677int __init tty_init(void)
3678{
3679 cdev_init(&tty_cdev, &tty_fops);
3680 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3681 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3682 panic("Couldn't register /dev/tty driver\n");
3683 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3684
3685 cdev_init(&console_cdev, &console_fops);
3686 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3687 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3688 panic("Couldn't register /dev/console driver\n");
3689 consdev = device_create_with_groups(tty_class, NULL,
3690 MKDEV(TTYAUX_MAJOR, 1), NULL,
3691 cons_dev_groups, "console");
3692 if (IS_ERR(consdev))
3693 consdev = NULL;
3694
3695#ifdef CONFIG_VT
3696 vty_init(&console_fops);
3697#endif
3698 return 0;
3699}
3700
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 */
5
6/*
7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
8 * or rs-channels. It also implements echoing, cooked mode etc.
9 *
10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 *
12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
13 * tty_struct and tty_queue structures. Previously there was an array
14 * of 256 tty_struct's which was statically allocated, and the
15 * tty_queue structures were allocated at boot time. Both are now
16 * dynamically allocated only when the tty is open.
17 *
18 * Also restructured routines so that there is more of a separation
19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
20 * the low-level tty routines (serial.c, pty.c, console.c). This
21 * makes for cleaner and more compact code. -TYT, 9/17/92
22 *
23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
24 * which can be dynamically activated and de-activated by the line
25 * discipline handling modules (like SLIP).
26 *
27 * NOTE: pay no attention to the line discipline code (yet); its
28 * interface is still subject to change in this version...
29 * -- TYT, 1/31/92
30 *
31 * Added functionality to the OPOST tty handling. No delays, but all
32 * other bits should be there.
33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 *
35 * Rewrote canonical mode and added more termios flags.
36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 *
38 * Reorganized FASYNC support so mouse code can share it.
39 * -- ctm@ardi.com, 9Sep95
40 *
41 * New TIOCLINUX variants added.
42 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 *
44 * Restrict vt switching via ioctl()
45 * -- grif@cs.ucr.edu, 5-Dec-95
46 *
47 * Move console and virtual terminal code to more appropriate files,
48 * implement CONFIG_VT and generalize console device interface.
49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 *
51 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
52 * -- Bill Hawes <whawes@star.net>, June 97
53 *
54 * Added devfs support.
55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 *
57 * Added support for a Unix98-style ptmx device.
58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 *
60 * Reduced memory usage for older ARM systems
61 * -- Russell King <rmk@arm.linux.org.uk>
62 *
63 * Move do_SAK() into process context. Less stack use in devfs functions.
64 * alloc_tty_struct() always uses kmalloc()
65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
66 */
67
68#include <linux/types.h>
69#include <linux/major.h>
70#include <linux/errno.h>
71#include <linux/signal.h>
72#include <linux/fcntl.h>
73#include <linux/sched/signal.h>
74#include <linux/sched/task.h>
75#include <linux/interrupt.h>
76#include <linux/tty.h>
77#include <linux/tty_driver.h>
78#include <linux/tty_flip.h>
79#include <linux/devpts_fs.h>
80#include <linux/file.h>
81#include <linux/fdtable.h>
82#include <linux/console.h>
83#include <linux/timer.h>
84#include <linux/ctype.h>
85#include <linux/kd.h>
86#include <linux/mm.h>
87#include <linux/string.h>
88#include <linux/slab.h>
89#include <linux/poll.h>
90#include <linux/proc_fs.h>
91#include <linux/init.h>
92#include <linux/module.h>
93#include <linux/device.h>
94#include <linux/wait.h>
95#include <linux/bitops.h>
96#include <linux/delay.h>
97#include <linux/seq_file.h>
98#include <linux/serial.h>
99#include <linux/ratelimit.h>
100#include <linux/compat.h>
101
102#include <linux/uaccess.h>
103
104#include <linux/kbd_kern.h>
105#include <linux/vt_kern.h>
106#include <linux/selection.h>
107
108#include <linux/kmod.h>
109#include <linux/nsproxy.h>
110
111#undef TTY_DEBUG_HANGUP
112#ifdef TTY_DEBUG_HANGUP
113# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
114#else
115# define tty_debug_hangup(tty, f, args...) do { } while (0)
116#endif
117
118#define TTY_PARANOIA_CHECK 1
119#define CHECK_TTY_COUNT 1
120
121struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
122 .c_iflag = ICRNL | IXON,
123 .c_oflag = OPOST | ONLCR,
124 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
125 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
126 ECHOCTL | ECHOKE | IEXTEN,
127 .c_cc = INIT_C_CC,
128 .c_ispeed = 38400,
129 .c_ospeed = 38400,
130 /* .c_line = N_TTY, */
131};
132
133EXPORT_SYMBOL(tty_std_termios);
134
135/* This list gets poked at by procfs and various bits of boot up code. This
136 could do with some rationalisation such as pulling the tty proc function
137 into this file */
138
139LIST_HEAD(tty_drivers); /* linked list of tty drivers */
140
141/* Mutex to protect creating and releasing a tty */
142DEFINE_MUTEX(tty_mutex);
143
144static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
145static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
146ssize_t redirected_tty_write(struct file *, const char __user *,
147 size_t, loff_t *);
148static __poll_t tty_poll(struct file *, poll_table *);
149static int tty_open(struct inode *, struct file *);
150long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
151#ifdef CONFIG_COMPAT
152static long tty_compat_ioctl(struct file *file, unsigned int cmd,
153 unsigned long arg);
154#else
155#define tty_compat_ioctl NULL
156#endif
157static int __tty_fasync(int fd, struct file *filp, int on);
158static int tty_fasync(int fd, struct file *filp, int on);
159static void release_tty(struct tty_struct *tty, int idx);
160
161/**
162 * free_tty_struct - free a disused tty
163 * @tty: tty struct to free
164 *
165 * Free the write buffers, tty queue and tty memory itself.
166 *
167 * Locking: none. Must be called after tty is definitely unused
168 */
169
170static void free_tty_struct(struct tty_struct *tty)
171{
172 tty_ldisc_deinit(tty);
173 put_device(tty->dev);
174 kfree(tty->write_buf);
175 tty->magic = 0xDEADDEAD;
176 kfree(tty);
177}
178
179static inline struct tty_struct *file_tty(struct file *file)
180{
181 return ((struct tty_file_private *)file->private_data)->tty;
182}
183
184int tty_alloc_file(struct file *file)
185{
186 struct tty_file_private *priv;
187
188 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
189 if (!priv)
190 return -ENOMEM;
191
192 file->private_data = priv;
193
194 return 0;
195}
196
197/* Associate a new file with the tty structure */
198void tty_add_file(struct tty_struct *tty, struct file *file)
199{
200 struct tty_file_private *priv = file->private_data;
201
202 priv->tty = tty;
203 priv->file = file;
204
205 spin_lock(&tty->files_lock);
206 list_add(&priv->list, &tty->tty_files);
207 spin_unlock(&tty->files_lock);
208}
209
210/**
211 * tty_free_file - free file->private_data
212 *
213 * This shall be used only for fail path handling when tty_add_file was not
214 * called yet.
215 */
216void tty_free_file(struct file *file)
217{
218 struct tty_file_private *priv = file->private_data;
219
220 file->private_data = NULL;
221 kfree(priv);
222}
223
224/* Delete file from its tty */
225static void tty_del_file(struct file *file)
226{
227 struct tty_file_private *priv = file->private_data;
228 struct tty_struct *tty = priv->tty;
229
230 spin_lock(&tty->files_lock);
231 list_del(&priv->list);
232 spin_unlock(&tty->files_lock);
233 tty_free_file(file);
234}
235
236/**
237 * tty_name - return tty naming
238 * @tty: tty structure
239 *
240 * Convert a tty structure into a name. The name reflects the kernel
241 * naming policy and if udev is in use may not reflect user space
242 *
243 * Locking: none
244 */
245
246const char *tty_name(const struct tty_struct *tty)
247{
248 if (!tty) /* Hmm. NULL pointer. That's fun. */
249 return "NULL tty";
250 return tty->name;
251}
252
253EXPORT_SYMBOL(tty_name);
254
255const char *tty_driver_name(const struct tty_struct *tty)
256{
257 if (!tty || !tty->driver)
258 return "";
259 return tty->driver->name;
260}
261
262static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
263 const char *routine)
264{
265#ifdef TTY_PARANOIA_CHECK
266 if (!tty) {
267 pr_warn("(%d:%d): %s: NULL tty\n",
268 imajor(inode), iminor(inode), routine);
269 return 1;
270 }
271 if (tty->magic != TTY_MAGIC) {
272 pr_warn("(%d:%d): %s: bad magic number\n",
273 imajor(inode), iminor(inode), routine);
274 return 1;
275 }
276#endif
277 return 0;
278}
279
280/* Caller must hold tty_lock */
281static int check_tty_count(struct tty_struct *tty, const char *routine)
282{
283#ifdef CHECK_TTY_COUNT
284 struct list_head *p;
285 int count = 0, kopen_count = 0;
286
287 spin_lock(&tty->files_lock);
288 list_for_each(p, &tty->tty_files) {
289 count++;
290 }
291 spin_unlock(&tty->files_lock);
292 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
293 tty->driver->subtype == PTY_TYPE_SLAVE &&
294 tty->link && tty->link->count)
295 count++;
296 if (tty_port_kopened(tty->port))
297 kopen_count++;
298 if (tty->count != (count + kopen_count)) {
299 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
300 routine, tty->count, count, kopen_count);
301 return (count + kopen_count);
302 }
303#endif
304 return 0;
305}
306
307/**
308 * get_tty_driver - find device of a tty
309 * @dev_t: device identifier
310 * @index: returns the index of the tty
311 *
312 * This routine returns a tty driver structure, given a device number
313 * and also passes back the index number.
314 *
315 * Locking: caller must hold tty_mutex
316 */
317
318static struct tty_driver *get_tty_driver(dev_t device, int *index)
319{
320 struct tty_driver *p;
321
322 list_for_each_entry(p, &tty_drivers, tty_drivers) {
323 dev_t base = MKDEV(p->major, p->minor_start);
324 if (device < base || device >= base + p->num)
325 continue;
326 *index = device - base;
327 return tty_driver_kref_get(p);
328 }
329 return NULL;
330}
331
332/**
333 * tty_dev_name_to_number - return dev_t for device name
334 * @name: user space name of device under /dev
335 * @number: pointer to dev_t that this function will populate
336 *
337 * This function converts device names like ttyS0 or ttyUSB1 into dev_t
338 * like (4, 64) or (188, 1). If no corresponding driver is registered then
339 * the function returns -ENODEV.
340 *
341 * Locking: this acquires tty_mutex to protect the tty_drivers list from
342 * being modified while we are traversing it, and makes sure to
343 * release it before exiting.
344 */
345int tty_dev_name_to_number(const char *name, dev_t *number)
346{
347 struct tty_driver *p;
348 int ret;
349 int index, prefix_length = 0;
350 const char *str;
351
352 for (str = name; *str && !isdigit(*str); str++)
353 ;
354
355 if (!*str)
356 return -EINVAL;
357
358 ret = kstrtoint(str, 10, &index);
359 if (ret)
360 return ret;
361
362 prefix_length = str - name;
363 mutex_lock(&tty_mutex);
364
365 list_for_each_entry(p, &tty_drivers, tty_drivers)
366 if (prefix_length == strlen(p->name) && strncmp(name,
367 p->name, prefix_length) == 0) {
368 if (index < p->num) {
369 *number = MKDEV(p->major, p->minor_start + index);
370 goto out;
371 }
372 }
373
374 /* if here then driver wasn't found */
375 ret = -ENODEV;
376out:
377 mutex_unlock(&tty_mutex);
378 return ret;
379}
380EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
381
382#ifdef CONFIG_CONSOLE_POLL
383
384/**
385 * tty_find_polling_driver - find device of a polled tty
386 * @name: name string to match
387 * @line: pointer to resulting tty line nr
388 *
389 * This routine returns a tty driver structure, given a name
390 * and the condition that the tty driver is capable of polled
391 * operation.
392 */
393struct tty_driver *tty_find_polling_driver(char *name, int *line)
394{
395 struct tty_driver *p, *res = NULL;
396 int tty_line = 0;
397 int len;
398 char *str, *stp;
399
400 for (str = name; *str; str++)
401 if ((*str >= '0' && *str <= '9') || *str == ',')
402 break;
403 if (!*str)
404 return NULL;
405
406 len = str - name;
407 tty_line = simple_strtoul(str, &str, 10);
408
409 mutex_lock(&tty_mutex);
410 /* Search through the tty devices to look for a match */
411 list_for_each_entry(p, &tty_drivers, tty_drivers) {
412 if (!len || strncmp(name, p->name, len) != 0)
413 continue;
414 stp = str;
415 if (*stp == ',')
416 stp++;
417 if (*stp == '\0')
418 stp = NULL;
419
420 if (tty_line >= 0 && tty_line < p->num && p->ops &&
421 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
422 res = tty_driver_kref_get(p);
423 *line = tty_line;
424 break;
425 }
426 }
427 mutex_unlock(&tty_mutex);
428
429 return res;
430}
431EXPORT_SYMBOL_GPL(tty_find_polling_driver);
432#endif
433
434static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
435 size_t count, loff_t *ppos)
436{
437 return 0;
438}
439
440static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
441 size_t count, loff_t *ppos)
442{
443 return -EIO;
444}
445
446/* No kernel lock held - none needed ;) */
447static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
448{
449 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
450}
451
452static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
453 unsigned long arg)
454{
455 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
456}
457
458static long hung_up_tty_compat_ioctl(struct file *file,
459 unsigned int cmd, unsigned long arg)
460{
461 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
462}
463
464static int hung_up_tty_fasync(int fd, struct file *file, int on)
465{
466 return -ENOTTY;
467}
468
469static void tty_show_fdinfo(struct seq_file *m, struct file *file)
470{
471 struct tty_struct *tty = file_tty(file);
472
473 if (tty && tty->ops && tty->ops->show_fdinfo)
474 tty->ops->show_fdinfo(tty, m);
475}
476
477static const struct file_operations tty_fops = {
478 .llseek = no_llseek,
479 .read = tty_read,
480 .write = tty_write,
481 .poll = tty_poll,
482 .unlocked_ioctl = tty_ioctl,
483 .compat_ioctl = tty_compat_ioctl,
484 .open = tty_open,
485 .release = tty_release,
486 .fasync = tty_fasync,
487 .show_fdinfo = tty_show_fdinfo,
488};
489
490static const struct file_operations console_fops = {
491 .llseek = no_llseek,
492 .read = tty_read,
493 .write = redirected_tty_write,
494 .poll = tty_poll,
495 .unlocked_ioctl = tty_ioctl,
496 .compat_ioctl = tty_compat_ioctl,
497 .open = tty_open,
498 .release = tty_release,
499 .fasync = tty_fasync,
500};
501
502static const struct file_operations hung_up_tty_fops = {
503 .llseek = no_llseek,
504 .read = hung_up_tty_read,
505 .write = hung_up_tty_write,
506 .poll = hung_up_tty_poll,
507 .unlocked_ioctl = hung_up_tty_ioctl,
508 .compat_ioctl = hung_up_tty_compat_ioctl,
509 .release = tty_release,
510 .fasync = hung_up_tty_fasync,
511};
512
513static DEFINE_SPINLOCK(redirect_lock);
514static struct file *redirect;
515
516extern void tty_sysctl_init(void);
517
518/**
519 * tty_wakeup - request more data
520 * @tty: terminal
521 *
522 * Internal and external helper for wakeups of tty. This function
523 * informs the line discipline if present that the driver is ready
524 * to receive more output data.
525 */
526
527void tty_wakeup(struct tty_struct *tty)
528{
529 struct tty_ldisc *ld;
530
531 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
532 ld = tty_ldisc_ref(tty);
533 if (ld) {
534 if (ld->ops->write_wakeup)
535 ld->ops->write_wakeup(tty);
536 tty_ldisc_deref(ld);
537 }
538 }
539 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
540}
541
542EXPORT_SYMBOL_GPL(tty_wakeup);
543
544/**
545 * __tty_hangup - actual handler for hangup events
546 * @work: tty device
547 *
548 * This can be called by a "kworker" kernel thread. That is process
549 * synchronous but doesn't hold any locks, so we need to make sure we
550 * have the appropriate locks for what we're doing.
551 *
552 * The hangup event clears any pending redirections onto the hung up
553 * device. It ensures future writes will error and it does the needed
554 * line discipline hangup and signal delivery. The tty object itself
555 * remains intact.
556 *
557 * Locking:
558 * BTM
559 * redirect lock for undoing redirection
560 * file list lock for manipulating list of ttys
561 * tty_ldiscs_lock from called functions
562 * termios_rwsem resetting termios data
563 * tasklist_lock to walk task list for hangup event
564 * ->siglock to protect ->signal/->sighand
565 */
566static void __tty_hangup(struct tty_struct *tty, int exit_session)
567{
568 struct file *cons_filp = NULL;
569 struct file *filp, *f = NULL;
570 struct tty_file_private *priv;
571 int closecount = 0, n;
572 int refs;
573
574 if (!tty)
575 return;
576
577
578 spin_lock(&redirect_lock);
579 if (redirect && file_tty(redirect) == tty) {
580 f = redirect;
581 redirect = NULL;
582 }
583 spin_unlock(&redirect_lock);
584
585 tty_lock(tty);
586
587 if (test_bit(TTY_HUPPED, &tty->flags)) {
588 tty_unlock(tty);
589 return;
590 }
591
592 /*
593 * Some console devices aren't actually hung up for technical and
594 * historical reasons, which can lead to indefinite interruptible
595 * sleep in n_tty_read(). The following explicitly tells
596 * n_tty_read() to abort readers.
597 */
598 set_bit(TTY_HUPPING, &tty->flags);
599
600 /* inuse_filps is protected by the single tty lock,
601 this really needs to change if we want to flush the
602 workqueue with the lock held */
603 check_tty_count(tty, "tty_hangup");
604
605 spin_lock(&tty->files_lock);
606 /* This breaks for file handles being sent over AF_UNIX sockets ? */
607 list_for_each_entry(priv, &tty->tty_files, list) {
608 filp = priv->file;
609 if (filp->f_op->write == redirected_tty_write)
610 cons_filp = filp;
611 if (filp->f_op->write != tty_write)
612 continue;
613 closecount++;
614 __tty_fasync(-1, filp, 0); /* can't block */
615 filp->f_op = &hung_up_tty_fops;
616 }
617 spin_unlock(&tty->files_lock);
618
619 refs = tty_signal_session_leader(tty, exit_session);
620 /* Account for the p->signal references we killed */
621 while (refs--)
622 tty_kref_put(tty);
623
624 tty_ldisc_hangup(tty, cons_filp != NULL);
625
626 spin_lock_irq(&tty->ctrl_lock);
627 clear_bit(TTY_THROTTLED, &tty->flags);
628 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
629 put_pid(tty->session);
630 put_pid(tty->pgrp);
631 tty->session = NULL;
632 tty->pgrp = NULL;
633 tty->ctrl_status = 0;
634 spin_unlock_irq(&tty->ctrl_lock);
635
636 /*
637 * If one of the devices matches a console pointer, we
638 * cannot just call hangup() because that will cause
639 * tty->count and state->count to go out of sync.
640 * So we just call close() the right number of times.
641 */
642 if (cons_filp) {
643 if (tty->ops->close)
644 for (n = 0; n < closecount; n++)
645 tty->ops->close(tty, cons_filp);
646 } else if (tty->ops->hangup)
647 tty->ops->hangup(tty);
648 /*
649 * We don't want to have driver/ldisc interactions beyond the ones
650 * we did here. The driver layer expects no calls after ->hangup()
651 * from the ldisc side, which is now guaranteed.
652 */
653 set_bit(TTY_HUPPED, &tty->flags);
654 clear_bit(TTY_HUPPING, &tty->flags);
655 tty_unlock(tty);
656
657 if (f)
658 fput(f);
659}
660
661static void do_tty_hangup(struct work_struct *work)
662{
663 struct tty_struct *tty =
664 container_of(work, struct tty_struct, hangup_work);
665
666 __tty_hangup(tty, 0);
667}
668
669/**
670 * tty_hangup - trigger a hangup event
671 * @tty: tty to hangup
672 *
673 * A carrier loss (virtual or otherwise) has occurred on this like
674 * schedule a hangup sequence to run after this event.
675 */
676
677void tty_hangup(struct tty_struct *tty)
678{
679 tty_debug_hangup(tty, "hangup\n");
680 schedule_work(&tty->hangup_work);
681}
682
683EXPORT_SYMBOL(tty_hangup);
684
685/**
686 * tty_vhangup - process vhangup
687 * @tty: tty to hangup
688 *
689 * The user has asked via system call for the terminal to be hung up.
690 * We do this synchronously so that when the syscall returns the process
691 * is complete. That guarantee is necessary for security reasons.
692 */
693
694void tty_vhangup(struct tty_struct *tty)
695{
696 tty_debug_hangup(tty, "vhangup\n");
697 __tty_hangup(tty, 0);
698}
699
700EXPORT_SYMBOL(tty_vhangup);
701
702
703/**
704 * tty_vhangup_self - process vhangup for own ctty
705 *
706 * Perform a vhangup on the current controlling tty
707 */
708
709void tty_vhangup_self(void)
710{
711 struct tty_struct *tty;
712
713 tty = get_current_tty();
714 if (tty) {
715 tty_vhangup(tty);
716 tty_kref_put(tty);
717 }
718}
719
720/**
721 * tty_vhangup_session - hangup session leader exit
722 * @tty: tty to hangup
723 *
724 * The session leader is exiting and hanging up its controlling terminal.
725 * Every process in the foreground process group is signalled SIGHUP.
726 *
727 * We do this synchronously so that when the syscall returns the process
728 * is complete. That guarantee is necessary for security reasons.
729 */
730
731void tty_vhangup_session(struct tty_struct *tty)
732{
733 tty_debug_hangup(tty, "session hangup\n");
734 __tty_hangup(tty, 1);
735}
736
737/**
738 * tty_hung_up_p - was tty hung up
739 * @filp: file pointer of tty
740 *
741 * Return true if the tty has been subject to a vhangup or a carrier
742 * loss
743 */
744
745int tty_hung_up_p(struct file *filp)
746{
747 return (filp && filp->f_op == &hung_up_tty_fops);
748}
749
750EXPORT_SYMBOL(tty_hung_up_p);
751
752/**
753 * stop_tty - propagate flow control
754 * @tty: tty to stop
755 *
756 * Perform flow control to the driver. May be called
757 * on an already stopped device and will not re-call the driver
758 * method.
759 *
760 * This functionality is used by both the line disciplines for
761 * halting incoming flow and by the driver. It may therefore be
762 * called from any context, may be under the tty atomic_write_lock
763 * but not always.
764 *
765 * Locking:
766 * flow_lock
767 */
768
769void __stop_tty(struct tty_struct *tty)
770{
771 if (tty->stopped)
772 return;
773 tty->stopped = 1;
774 if (tty->ops->stop)
775 tty->ops->stop(tty);
776}
777
778void stop_tty(struct tty_struct *tty)
779{
780 unsigned long flags;
781
782 spin_lock_irqsave(&tty->flow_lock, flags);
783 __stop_tty(tty);
784 spin_unlock_irqrestore(&tty->flow_lock, flags);
785}
786EXPORT_SYMBOL(stop_tty);
787
788/**
789 * start_tty - propagate flow control
790 * @tty: tty to start
791 *
792 * Start a tty that has been stopped if at all possible. If this
793 * tty was previous stopped and is now being started, the driver
794 * start method is invoked and the line discipline woken.
795 *
796 * Locking:
797 * flow_lock
798 */
799
800void __start_tty(struct tty_struct *tty)
801{
802 if (!tty->stopped || tty->flow_stopped)
803 return;
804 tty->stopped = 0;
805 if (tty->ops->start)
806 tty->ops->start(tty);
807 tty_wakeup(tty);
808}
809
810void start_tty(struct tty_struct *tty)
811{
812 unsigned long flags;
813
814 spin_lock_irqsave(&tty->flow_lock, flags);
815 __start_tty(tty);
816 spin_unlock_irqrestore(&tty->flow_lock, flags);
817}
818EXPORT_SYMBOL(start_tty);
819
820static void tty_update_time(struct timespec64 *time)
821{
822 time64_t sec = ktime_get_real_seconds();
823
824 /*
825 * We only care if the two values differ in anything other than the
826 * lower three bits (i.e every 8 seconds). If so, then we can update
827 * the time of the tty device, otherwise it could be construded as a
828 * security leak to let userspace know the exact timing of the tty.
829 */
830 if ((sec ^ time->tv_sec) & ~7)
831 time->tv_sec = sec;
832}
833
834/**
835 * tty_read - read method for tty device files
836 * @file: pointer to tty file
837 * @buf: user buffer
838 * @count: size of user buffer
839 * @ppos: unused
840 *
841 * Perform the read system call function on this terminal device. Checks
842 * for hung up devices before calling the line discipline method.
843 *
844 * Locking:
845 * Locks the line discipline internally while needed. Multiple
846 * read calls may be outstanding in parallel.
847 */
848
849static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
850 loff_t *ppos)
851{
852 int i;
853 struct inode *inode = file_inode(file);
854 struct tty_struct *tty = file_tty(file);
855 struct tty_ldisc *ld;
856
857 if (tty_paranoia_check(tty, inode, "tty_read"))
858 return -EIO;
859 if (!tty || tty_io_error(tty))
860 return -EIO;
861
862 /* We want to wait for the line discipline to sort out in this
863 situation */
864 ld = tty_ldisc_ref_wait(tty);
865 if (!ld)
866 return hung_up_tty_read(file, buf, count, ppos);
867 if (ld->ops->read)
868 i = ld->ops->read(tty, file, buf, count);
869 else
870 i = -EIO;
871 tty_ldisc_deref(ld);
872
873 if (i > 0)
874 tty_update_time(&inode->i_atime);
875
876 return i;
877}
878
879static void tty_write_unlock(struct tty_struct *tty)
880{
881 mutex_unlock(&tty->atomic_write_lock);
882 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
883}
884
885static int tty_write_lock(struct tty_struct *tty, int ndelay)
886{
887 if (!mutex_trylock(&tty->atomic_write_lock)) {
888 if (ndelay)
889 return -EAGAIN;
890 if (mutex_lock_interruptible(&tty->atomic_write_lock))
891 return -ERESTARTSYS;
892 }
893 return 0;
894}
895
896/*
897 * Split writes up in sane blocksizes to avoid
898 * denial-of-service type attacks
899 */
900static inline ssize_t do_tty_write(
901 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
902 struct tty_struct *tty,
903 struct file *file,
904 const char __user *buf,
905 size_t count)
906{
907 ssize_t ret, written = 0;
908 unsigned int chunk;
909
910 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
911 if (ret < 0)
912 return ret;
913
914 /*
915 * We chunk up writes into a temporary buffer. This
916 * simplifies low-level drivers immensely, since they
917 * don't have locking issues and user mode accesses.
918 *
919 * But if TTY_NO_WRITE_SPLIT is set, we should use a
920 * big chunk-size..
921 *
922 * The default chunk-size is 2kB, because the NTTY
923 * layer has problems with bigger chunks. It will
924 * claim to be able to handle more characters than
925 * it actually does.
926 *
927 * FIXME: This can probably go away now except that 64K chunks
928 * are too likely to fail unless switched to vmalloc...
929 */
930 chunk = 2048;
931 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
932 chunk = 65536;
933 if (count < chunk)
934 chunk = count;
935
936 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
937 if (tty->write_cnt < chunk) {
938 unsigned char *buf_chunk;
939
940 if (chunk < 1024)
941 chunk = 1024;
942
943 buf_chunk = kmalloc(chunk, GFP_KERNEL);
944 if (!buf_chunk) {
945 ret = -ENOMEM;
946 goto out;
947 }
948 kfree(tty->write_buf);
949 tty->write_cnt = chunk;
950 tty->write_buf = buf_chunk;
951 }
952
953 /* Do the write .. */
954 for (;;) {
955 size_t size = count;
956 if (size > chunk)
957 size = chunk;
958 ret = -EFAULT;
959 if (copy_from_user(tty->write_buf, buf, size))
960 break;
961 ret = write(tty, file, tty->write_buf, size);
962 if (ret <= 0)
963 break;
964 written += ret;
965 buf += ret;
966 count -= ret;
967 if (!count)
968 break;
969 ret = -ERESTARTSYS;
970 if (signal_pending(current))
971 break;
972 cond_resched();
973 }
974 if (written) {
975 tty_update_time(&file_inode(file)->i_mtime);
976 ret = written;
977 }
978out:
979 tty_write_unlock(tty);
980 return ret;
981}
982
983/**
984 * tty_write_message - write a message to a certain tty, not just the console.
985 * @tty: the destination tty_struct
986 * @msg: the message to write
987 *
988 * This is used for messages that need to be redirected to a specific tty.
989 * We don't put it into the syslog queue right now maybe in the future if
990 * really needed.
991 *
992 * We must still hold the BTM and test the CLOSING flag for the moment.
993 */
994
995void tty_write_message(struct tty_struct *tty, char *msg)
996{
997 if (tty) {
998 mutex_lock(&tty->atomic_write_lock);
999 tty_lock(tty);
1000 if (tty->ops->write && tty->count > 0)
1001 tty->ops->write(tty, msg, strlen(msg));
1002 tty_unlock(tty);
1003 tty_write_unlock(tty);
1004 }
1005 return;
1006}
1007
1008
1009/**
1010 * tty_write - write method for tty device file
1011 * @file: tty file pointer
1012 * @buf: user data to write
1013 * @count: bytes to write
1014 * @ppos: unused
1015 *
1016 * Write data to a tty device via the line discipline.
1017 *
1018 * Locking:
1019 * Locks the line discipline as required
1020 * Writes to the tty driver are serialized by the atomic_write_lock
1021 * and are then processed in chunks to the device. The line discipline
1022 * write method will not be invoked in parallel for each device.
1023 */
1024
1025static ssize_t tty_write(struct file *file, const char __user *buf,
1026 size_t count, loff_t *ppos)
1027{
1028 struct tty_struct *tty = file_tty(file);
1029 struct tty_ldisc *ld;
1030 ssize_t ret;
1031
1032 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1033 return -EIO;
1034 if (!tty || !tty->ops->write || tty_io_error(tty))
1035 return -EIO;
1036 /* Short term debug to catch buggy drivers */
1037 if (tty->ops->write_room == NULL)
1038 tty_err(tty, "missing write_room method\n");
1039 ld = tty_ldisc_ref_wait(tty);
1040 if (!ld)
1041 return hung_up_tty_write(file, buf, count, ppos);
1042 if (!ld->ops->write)
1043 ret = -EIO;
1044 else
1045 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1046 tty_ldisc_deref(ld);
1047 return ret;
1048}
1049
1050ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1051 size_t count, loff_t *ppos)
1052{
1053 struct file *p = NULL;
1054
1055 spin_lock(&redirect_lock);
1056 if (redirect)
1057 p = get_file(redirect);
1058 spin_unlock(&redirect_lock);
1059
1060 if (p) {
1061 ssize_t res;
1062 res = vfs_write(p, buf, count, &p->f_pos);
1063 fput(p);
1064 return res;
1065 }
1066 return tty_write(file, buf, count, ppos);
1067}
1068
1069/**
1070 * tty_send_xchar - send priority character
1071 *
1072 * Send a high priority character to the tty even if stopped
1073 *
1074 * Locking: none for xchar method, write ordering for write method.
1075 */
1076
1077int tty_send_xchar(struct tty_struct *tty, char ch)
1078{
1079 int was_stopped = tty->stopped;
1080
1081 if (tty->ops->send_xchar) {
1082 down_read(&tty->termios_rwsem);
1083 tty->ops->send_xchar(tty, ch);
1084 up_read(&tty->termios_rwsem);
1085 return 0;
1086 }
1087
1088 if (tty_write_lock(tty, 0) < 0)
1089 return -ERESTARTSYS;
1090
1091 down_read(&tty->termios_rwsem);
1092 if (was_stopped)
1093 start_tty(tty);
1094 tty->ops->write(tty, &ch, 1);
1095 if (was_stopped)
1096 stop_tty(tty);
1097 up_read(&tty->termios_rwsem);
1098 tty_write_unlock(tty);
1099 return 0;
1100}
1101
1102static char ptychar[] = "pqrstuvwxyzabcde";
1103
1104/**
1105 * pty_line_name - generate name for a pty
1106 * @driver: the tty driver in use
1107 * @index: the minor number
1108 * @p: output buffer of at least 6 bytes
1109 *
1110 * Generate a name from a driver reference and write it to the output
1111 * buffer.
1112 *
1113 * Locking: None
1114 */
1115static void pty_line_name(struct tty_driver *driver, int index, char *p)
1116{
1117 int i = index + driver->name_base;
1118 /* ->name is initialized to "ttyp", but "tty" is expected */
1119 sprintf(p, "%s%c%x",
1120 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1121 ptychar[i >> 4 & 0xf], i & 0xf);
1122}
1123
1124/**
1125 * tty_line_name - generate name for a tty
1126 * @driver: the tty driver in use
1127 * @index: the minor number
1128 * @p: output buffer of at least 7 bytes
1129 *
1130 * Generate a name from a driver reference and write it to the output
1131 * buffer.
1132 *
1133 * Locking: None
1134 */
1135static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1136{
1137 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1138 return sprintf(p, "%s", driver->name);
1139 else
1140 return sprintf(p, "%s%d", driver->name,
1141 index + driver->name_base);
1142}
1143
1144/**
1145 * tty_driver_lookup_tty() - find an existing tty, if any
1146 * @driver: the driver for the tty
1147 * @idx: the minor number
1148 *
1149 * Return the tty, if found. If not found, return NULL or ERR_PTR() if the
1150 * driver lookup() method returns an error.
1151 *
1152 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1153 */
1154static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1155 struct file *file, int idx)
1156{
1157 struct tty_struct *tty;
1158
1159 if (driver->ops->lookup)
1160 if (!file)
1161 tty = ERR_PTR(-EIO);
1162 else
1163 tty = driver->ops->lookup(driver, file, idx);
1164 else
1165 tty = driver->ttys[idx];
1166
1167 if (!IS_ERR(tty))
1168 tty_kref_get(tty);
1169 return tty;
1170}
1171
1172/**
1173 * tty_init_termios - helper for termios setup
1174 * @tty: the tty to set up
1175 *
1176 * Initialise the termios structure for this tty. This runs under
1177 * the tty_mutex currently so we can be relaxed about ordering.
1178 */
1179
1180void tty_init_termios(struct tty_struct *tty)
1181{
1182 struct ktermios *tp;
1183 int idx = tty->index;
1184
1185 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1186 tty->termios = tty->driver->init_termios;
1187 else {
1188 /* Check for lazy saved data */
1189 tp = tty->driver->termios[idx];
1190 if (tp != NULL) {
1191 tty->termios = *tp;
1192 tty->termios.c_line = tty->driver->init_termios.c_line;
1193 } else
1194 tty->termios = tty->driver->init_termios;
1195 }
1196 /* Compatibility until drivers always set this */
1197 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1198 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1199}
1200EXPORT_SYMBOL_GPL(tty_init_termios);
1201
1202int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1203{
1204 tty_init_termios(tty);
1205 tty_driver_kref_get(driver);
1206 tty->count++;
1207 driver->ttys[tty->index] = tty;
1208 return 0;
1209}
1210EXPORT_SYMBOL_GPL(tty_standard_install);
1211
1212/**
1213 * tty_driver_install_tty() - install a tty entry in the driver
1214 * @driver: the driver for the tty
1215 * @tty: the tty
1216 *
1217 * Install a tty object into the driver tables. The tty->index field
1218 * will be set by the time this is called. This method is responsible
1219 * for ensuring any need additional structures are allocated and
1220 * configured.
1221 *
1222 * Locking: tty_mutex for now
1223 */
1224static int tty_driver_install_tty(struct tty_driver *driver,
1225 struct tty_struct *tty)
1226{
1227 return driver->ops->install ? driver->ops->install(driver, tty) :
1228 tty_standard_install(driver, tty);
1229}
1230
1231/**
1232 * tty_driver_remove_tty() - remove a tty from the driver tables
1233 * @driver: the driver for the tty
1234 * @idx: the minor number
1235 *
1236 * Remvoe a tty object from the driver tables. The tty->index field
1237 * will be set by the time this is called.
1238 *
1239 * Locking: tty_mutex for now
1240 */
1241static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1242{
1243 if (driver->ops->remove)
1244 driver->ops->remove(driver, tty);
1245 else
1246 driver->ttys[tty->index] = NULL;
1247}
1248
1249/*
1250 * tty_reopen() - fast re-open of an open tty
1251 * @tty - the tty to open
1252 *
1253 * Return 0 on success, -errno on error.
1254 * Re-opens on master ptys are not allowed and return -EIO.
1255 *
1256 * Locking: Caller must hold tty_lock
1257 */
1258static int tty_reopen(struct tty_struct *tty)
1259{
1260 struct tty_driver *driver = tty->driver;
1261 struct tty_ldisc *ld;
1262 int retval = 0;
1263
1264 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1265 driver->subtype == PTY_TYPE_MASTER)
1266 return -EIO;
1267
1268 if (!tty->count)
1269 return -EAGAIN;
1270
1271 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1272 return -EBUSY;
1273
1274 ld = tty_ldisc_ref_wait(tty);
1275 if (ld) {
1276 tty_ldisc_deref(ld);
1277 } else {
1278 retval = tty_ldisc_lock(tty, 5 * HZ);
1279 if (retval)
1280 return retval;
1281
1282 if (!tty->ldisc)
1283 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1284 tty_ldisc_unlock(tty);
1285 }
1286
1287 if (retval == 0)
1288 tty->count++;
1289
1290 return retval;
1291}
1292
1293/**
1294 * tty_init_dev - initialise a tty device
1295 * @driver: tty driver we are opening a device on
1296 * @idx: device index
1297 * @ret_tty: returned tty structure
1298 *
1299 * Prepare a tty device. This may not be a "new" clean device but
1300 * could also be an active device. The pty drivers require special
1301 * handling because of this.
1302 *
1303 * Locking:
1304 * The function is called under the tty_mutex, which
1305 * protects us from the tty struct or driver itself going away.
1306 *
1307 * On exit the tty device has the line discipline attached and
1308 * a reference count of 1. If a pair was created for pty/tty use
1309 * and the other was a pty master then it too has a reference count of 1.
1310 *
1311 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1312 * failed open. The new code protects the open with a mutex, so it's
1313 * really quite straightforward. The mutex locking can probably be
1314 * relaxed for the (most common) case of reopening a tty.
1315 */
1316
1317struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1318{
1319 struct tty_struct *tty;
1320 int retval;
1321
1322 /*
1323 * First time open is complex, especially for PTY devices.
1324 * This code guarantees that either everything succeeds and the
1325 * TTY is ready for operation, or else the table slots are vacated
1326 * and the allocated memory released. (Except that the termios
1327 * may be retained.)
1328 */
1329
1330 if (!try_module_get(driver->owner))
1331 return ERR_PTR(-ENODEV);
1332
1333 tty = alloc_tty_struct(driver, idx);
1334 if (!tty) {
1335 retval = -ENOMEM;
1336 goto err_module_put;
1337 }
1338
1339 tty_lock(tty);
1340 retval = tty_driver_install_tty(driver, tty);
1341 if (retval < 0)
1342 goto err_free_tty;
1343
1344 if (!tty->port)
1345 tty->port = driver->ports[idx];
1346
1347 WARN_RATELIMIT(!tty->port,
1348 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1349 __func__, tty->driver->name);
1350
1351 retval = tty_ldisc_lock(tty, 5 * HZ);
1352 if (retval)
1353 goto err_release_lock;
1354 tty->port->itty = tty;
1355
1356 /*
1357 * Structures all installed ... call the ldisc open routines.
1358 * If we fail here just call release_tty to clean up. No need
1359 * to decrement the use counts, as release_tty doesn't care.
1360 */
1361 retval = tty_ldisc_setup(tty, tty->link);
1362 if (retval)
1363 goto err_release_tty;
1364 tty_ldisc_unlock(tty);
1365 /* Return the tty locked so that it cannot vanish under the caller */
1366 return tty;
1367
1368err_free_tty:
1369 tty_unlock(tty);
1370 free_tty_struct(tty);
1371err_module_put:
1372 module_put(driver->owner);
1373 return ERR_PTR(retval);
1374
1375 /* call the tty release_tty routine to clean out this slot */
1376err_release_tty:
1377 tty_ldisc_unlock(tty);
1378 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1379 retval, idx);
1380err_release_lock:
1381 tty_unlock(tty);
1382 release_tty(tty, idx);
1383 return ERR_PTR(retval);
1384}
1385
1386/**
1387 * tty_save_termios() - save tty termios data in driver table
1388 * @tty: tty whose termios data to save
1389 *
1390 * Locking: Caller guarantees serialisation with tty_init_termios().
1391 */
1392void tty_save_termios(struct tty_struct *tty)
1393{
1394 struct ktermios *tp;
1395 int idx = tty->index;
1396
1397 /* If the port is going to reset then it has no termios to save */
1398 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1399 return;
1400
1401 /* Stash the termios data */
1402 tp = tty->driver->termios[idx];
1403 if (tp == NULL) {
1404 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1405 if (tp == NULL)
1406 return;
1407 tty->driver->termios[idx] = tp;
1408 }
1409 *tp = tty->termios;
1410}
1411EXPORT_SYMBOL_GPL(tty_save_termios);
1412
1413/**
1414 * tty_flush_works - flush all works of a tty/pty pair
1415 * @tty: tty device to flush works for (or either end of a pty pair)
1416 *
1417 * Sync flush all works belonging to @tty (and the 'other' tty).
1418 */
1419static void tty_flush_works(struct tty_struct *tty)
1420{
1421 flush_work(&tty->SAK_work);
1422 flush_work(&tty->hangup_work);
1423 if (tty->link) {
1424 flush_work(&tty->link->SAK_work);
1425 flush_work(&tty->link->hangup_work);
1426 }
1427}
1428
1429/**
1430 * release_one_tty - release tty structure memory
1431 * @kref: kref of tty we are obliterating
1432 *
1433 * Releases memory associated with a tty structure, and clears out the
1434 * driver table slots. This function is called when a device is no longer
1435 * in use. It also gets called when setup of a device fails.
1436 *
1437 * Locking:
1438 * takes the file list lock internally when working on the list
1439 * of ttys that the driver keeps.
1440 *
1441 * This method gets called from a work queue so that the driver private
1442 * cleanup ops can sleep (needed for USB at least)
1443 */
1444static void release_one_tty(struct work_struct *work)
1445{
1446 struct tty_struct *tty =
1447 container_of(work, struct tty_struct, hangup_work);
1448 struct tty_driver *driver = tty->driver;
1449 struct module *owner = driver->owner;
1450
1451 if (tty->ops->cleanup)
1452 tty->ops->cleanup(tty);
1453
1454 tty->magic = 0;
1455 tty_driver_kref_put(driver);
1456 module_put(owner);
1457
1458 spin_lock(&tty->files_lock);
1459 list_del_init(&tty->tty_files);
1460 spin_unlock(&tty->files_lock);
1461
1462 put_pid(tty->pgrp);
1463 put_pid(tty->session);
1464 free_tty_struct(tty);
1465}
1466
1467static void queue_release_one_tty(struct kref *kref)
1468{
1469 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1470
1471 /* The hangup queue is now free so we can reuse it rather than
1472 waste a chunk of memory for each port */
1473 INIT_WORK(&tty->hangup_work, release_one_tty);
1474 schedule_work(&tty->hangup_work);
1475}
1476
1477/**
1478 * tty_kref_put - release a tty kref
1479 * @tty: tty device
1480 *
1481 * Release a reference to a tty device and if need be let the kref
1482 * layer destruct the object for us
1483 */
1484
1485void tty_kref_put(struct tty_struct *tty)
1486{
1487 if (tty)
1488 kref_put(&tty->kref, queue_release_one_tty);
1489}
1490EXPORT_SYMBOL(tty_kref_put);
1491
1492/**
1493 * release_tty - release tty structure memory
1494 *
1495 * Release both @tty and a possible linked partner (think pty pair),
1496 * and decrement the refcount of the backing module.
1497 *
1498 * Locking:
1499 * tty_mutex
1500 * takes the file list lock internally when working on the list
1501 * of ttys that the driver keeps.
1502 *
1503 */
1504static void release_tty(struct tty_struct *tty, int idx)
1505{
1506 /* This should always be true but check for the moment */
1507 WARN_ON(tty->index != idx);
1508 WARN_ON(!mutex_is_locked(&tty_mutex));
1509 if (tty->ops->shutdown)
1510 tty->ops->shutdown(tty);
1511 tty_save_termios(tty);
1512 tty_driver_remove_tty(tty->driver, tty);
1513 tty->port->itty = NULL;
1514 if (tty->link)
1515 tty->link->port->itty = NULL;
1516 tty_buffer_cancel_work(tty->port);
1517 if (tty->link)
1518 tty_buffer_cancel_work(tty->link->port);
1519
1520 tty_kref_put(tty->link);
1521 tty_kref_put(tty);
1522}
1523
1524/**
1525 * tty_release_checks - check a tty before real release
1526 * @tty: tty to check
1527 * @o_tty: link of @tty (if any)
1528 * @idx: index of the tty
1529 *
1530 * Performs some paranoid checking before true release of the @tty.
1531 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1532 */
1533static int tty_release_checks(struct tty_struct *tty, int idx)
1534{
1535#ifdef TTY_PARANOIA_CHECK
1536 if (idx < 0 || idx >= tty->driver->num) {
1537 tty_debug(tty, "bad idx %d\n", idx);
1538 return -1;
1539 }
1540
1541 /* not much to check for devpts */
1542 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1543 return 0;
1544
1545 if (tty != tty->driver->ttys[idx]) {
1546 tty_debug(tty, "bad driver table[%d] = %p\n",
1547 idx, tty->driver->ttys[idx]);
1548 return -1;
1549 }
1550 if (tty->driver->other) {
1551 struct tty_struct *o_tty = tty->link;
1552
1553 if (o_tty != tty->driver->other->ttys[idx]) {
1554 tty_debug(tty, "bad other table[%d] = %p\n",
1555 idx, tty->driver->other->ttys[idx]);
1556 return -1;
1557 }
1558 if (o_tty->link != tty) {
1559 tty_debug(tty, "bad link = %p\n", o_tty->link);
1560 return -1;
1561 }
1562 }
1563#endif
1564 return 0;
1565}
1566
1567/**
1568 * tty_kclose - closes tty opened by tty_kopen
1569 * @tty: tty device
1570 *
1571 * Performs the final steps to release and free a tty device. It is the
1572 * same as tty_release_struct except that it also resets TTY_PORT_KOPENED
1573 * flag on tty->port.
1574 */
1575void tty_kclose(struct tty_struct *tty)
1576{
1577 /*
1578 * Ask the line discipline code to release its structures
1579 */
1580 tty_ldisc_release(tty);
1581
1582 /* Wait for pending work before tty destruction commmences */
1583 tty_flush_works(tty);
1584
1585 tty_debug_hangup(tty, "freeing structure\n");
1586 /*
1587 * The release_tty function takes care of the details of clearing
1588 * the slots and preserving the termios structure. The tty_unlock_pair
1589 * should be safe as we keep a kref while the tty is locked (so the
1590 * unlock never unlocks a freed tty).
1591 */
1592 mutex_lock(&tty_mutex);
1593 tty_port_set_kopened(tty->port, 0);
1594 release_tty(tty, tty->index);
1595 mutex_unlock(&tty_mutex);
1596}
1597EXPORT_SYMBOL_GPL(tty_kclose);
1598
1599/**
1600 * tty_release_struct - release a tty struct
1601 * @tty: tty device
1602 * @idx: index of the tty
1603 *
1604 * Performs the final steps to release and free a tty device. It is
1605 * roughly the reverse of tty_init_dev.
1606 */
1607void tty_release_struct(struct tty_struct *tty, int idx)
1608{
1609 /*
1610 * Ask the line discipline code to release its structures
1611 */
1612 tty_ldisc_release(tty);
1613
1614 /* Wait for pending work before tty destruction commmences */
1615 tty_flush_works(tty);
1616
1617 tty_debug_hangup(tty, "freeing structure\n");
1618 /*
1619 * The release_tty function takes care of the details of clearing
1620 * the slots and preserving the termios structure. The tty_unlock_pair
1621 * should be safe as we keep a kref while the tty is locked (so the
1622 * unlock never unlocks a freed tty).
1623 */
1624 mutex_lock(&tty_mutex);
1625 release_tty(tty, idx);
1626 mutex_unlock(&tty_mutex);
1627}
1628EXPORT_SYMBOL_GPL(tty_release_struct);
1629
1630/**
1631 * tty_release - vfs callback for close
1632 * @inode: inode of tty
1633 * @filp: file pointer for handle to tty
1634 *
1635 * Called the last time each file handle is closed that references
1636 * this tty. There may however be several such references.
1637 *
1638 * Locking:
1639 * Takes bkl. See tty_release_dev
1640 *
1641 * Even releasing the tty structures is a tricky business.. We have
1642 * to be very careful that the structures are all released at the
1643 * same time, as interrupts might otherwise get the wrong pointers.
1644 *
1645 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1646 * lead to double frees or releasing memory still in use.
1647 */
1648
1649int tty_release(struct inode *inode, struct file *filp)
1650{
1651 struct tty_struct *tty = file_tty(filp);
1652 struct tty_struct *o_tty = NULL;
1653 int do_sleep, final;
1654 int idx;
1655 long timeout = 0;
1656 int once = 1;
1657
1658 if (tty_paranoia_check(tty, inode, __func__))
1659 return 0;
1660
1661 tty_lock(tty);
1662 check_tty_count(tty, __func__);
1663
1664 __tty_fasync(-1, filp, 0);
1665
1666 idx = tty->index;
1667 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1668 tty->driver->subtype == PTY_TYPE_MASTER)
1669 o_tty = tty->link;
1670
1671 if (tty_release_checks(tty, idx)) {
1672 tty_unlock(tty);
1673 return 0;
1674 }
1675
1676 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1677
1678 if (tty->ops->close)
1679 tty->ops->close(tty, filp);
1680
1681 /* If tty is pty master, lock the slave pty (stable lock order) */
1682 tty_lock_slave(o_tty);
1683
1684 /*
1685 * Sanity check: if tty->count is going to zero, there shouldn't be
1686 * any waiters on tty->read_wait or tty->write_wait. We test the
1687 * wait queues and kick everyone out _before_ actually starting to
1688 * close. This ensures that we won't block while releasing the tty
1689 * structure.
1690 *
1691 * The test for the o_tty closing is necessary, since the master and
1692 * slave sides may close in any order. If the slave side closes out
1693 * first, its count will be one, since the master side holds an open.
1694 * Thus this test wouldn't be triggered at the time the slave closed,
1695 * so we do it now.
1696 */
1697 while (1) {
1698 do_sleep = 0;
1699
1700 if (tty->count <= 1) {
1701 if (waitqueue_active(&tty->read_wait)) {
1702 wake_up_poll(&tty->read_wait, EPOLLIN);
1703 do_sleep++;
1704 }
1705 if (waitqueue_active(&tty->write_wait)) {
1706 wake_up_poll(&tty->write_wait, EPOLLOUT);
1707 do_sleep++;
1708 }
1709 }
1710 if (o_tty && o_tty->count <= 1) {
1711 if (waitqueue_active(&o_tty->read_wait)) {
1712 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1713 do_sleep++;
1714 }
1715 if (waitqueue_active(&o_tty->write_wait)) {
1716 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1717 do_sleep++;
1718 }
1719 }
1720 if (!do_sleep)
1721 break;
1722
1723 if (once) {
1724 once = 0;
1725 tty_warn(tty, "read/write wait queue active!\n");
1726 }
1727 schedule_timeout_killable(timeout);
1728 if (timeout < 120 * HZ)
1729 timeout = 2 * timeout + 1;
1730 else
1731 timeout = MAX_SCHEDULE_TIMEOUT;
1732 }
1733
1734 if (o_tty) {
1735 if (--o_tty->count < 0) {
1736 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1737 o_tty->count = 0;
1738 }
1739 }
1740 if (--tty->count < 0) {
1741 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1742 tty->count = 0;
1743 }
1744
1745 /*
1746 * We've decremented tty->count, so we need to remove this file
1747 * descriptor off the tty->tty_files list; this serves two
1748 * purposes:
1749 * - check_tty_count sees the correct number of file descriptors
1750 * associated with this tty.
1751 * - do_tty_hangup no longer sees this file descriptor as
1752 * something that needs to be handled for hangups.
1753 */
1754 tty_del_file(filp);
1755
1756 /*
1757 * Perform some housekeeping before deciding whether to return.
1758 *
1759 * If _either_ side is closing, make sure there aren't any
1760 * processes that still think tty or o_tty is their controlling
1761 * tty.
1762 */
1763 if (!tty->count) {
1764 read_lock(&tasklist_lock);
1765 session_clear_tty(tty->session);
1766 if (o_tty)
1767 session_clear_tty(o_tty->session);
1768 read_unlock(&tasklist_lock);
1769 }
1770
1771 /* check whether both sides are closing ... */
1772 final = !tty->count && !(o_tty && o_tty->count);
1773
1774 tty_unlock_slave(o_tty);
1775 tty_unlock(tty);
1776
1777 /* At this point, the tty->count == 0 should ensure a dead tty
1778 cannot be re-opened by a racing opener */
1779
1780 if (!final)
1781 return 0;
1782
1783 tty_debug_hangup(tty, "final close\n");
1784
1785 tty_release_struct(tty, idx);
1786 return 0;
1787}
1788
1789/**
1790 * tty_open_current_tty - get locked tty of current task
1791 * @device: device number
1792 * @filp: file pointer to tty
1793 * @return: locked tty of the current task iff @device is /dev/tty
1794 *
1795 * Performs a re-open of the current task's controlling tty.
1796 *
1797 * We cannot return driver and index like for the other nodes because
1798 * devpts will not work then. It expects inodes to be from devpts FS.
1799 */
1800static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1801{
1802 struct tty_struct *tty;
1803 int retval;
1804
1805 if (device != MKDEV(TTYAUX_MAJOR, 0))
1806 return NULL;
1807
1808 tty = get_current_tty();
1809 if (!tty)
1810 return ERR_PTR(-ENXIO);
1811
1812 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1813 /* noctty = 1; */
1814 tty_lock(tty);
1815 tty_kref_put(tty); /* safe to drop the kref now */
1816
1817 retval = tty_reopen(tty);
1818 if (retval < 0) {
1819 tty_unlock(tty);
1820 tty = ERR_PTR(retval);
1821 }
1822 return tty;
1823}
1824
1825/**
1826 * tty_lookup_driver - lookup a tty driver for a given device file
1827 * @device: device number
1828 * @filp: file pointer to tty
1829 * @index: index for the device in the @return driver
1830 * @return: driver for this inode (with increased refcount)
1831 *
1832 * If @return is not erroneous, the caller is responsible to decrement the
1833 * refcount by tty_driver_kref_put.
1834 *
1835 * Locking: tty_mutex protects get_tty_driver
1836 */
1837static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1838 int *index)
1839{
1840 struct tty_driver *driver = NULL;
1841
1842 switch (device) {
1843#ifdef CONFIG_VT
1844 case MKDEV(TTY_MAJOR, 0): {
1845 extern struct tty_driver *console_driver;
1846 driver = tty_driver_kref_get(console_driver);
1847 *index = fg_console;
1848 break;
1849 }
1850#endif
1851 case MKDEV(TTYAUX_MAJOR, 1): {
1852 struct tty_driver *console_driver = console_device(index);
1853 if (console_driver) {
1854 driver = tty_driver_kref_get(console_driver);
1855 if (driver && filp) {
1856 /* Don't let /dev/console block */
1857 filp->f_flags |= O_NONBLOCK;
1858 break;
1859 }
1860 }
1861 if (driver)
1862 tty_driver_kref_put(driver);
1863 return ERR_PTR(-ENODEV);
1864 }
1865 default:
1866 driver = get_tty_driver(device, index);
1867 if (!driver)
1868 return ERR_PTR(-ENODEV);
1869 break;
1870 }
1871 return driver;
1872}
1873
1874/**
1875 * tty_kopen - open a tty device for kernel
1876 * @device: dev_t of device to open
1877 *
1878 * Opens tty exclusively for kernel. Performs the driver lookup,
1879 * makes sure it's not already opened and performs the first-time
1880 * tty initialization.
1881 *
1882 * Returns the locked initialized &tty_struct
1883 *
1884 * Claims the global tty_mutex to serialize:
1885 * - concurrent first-time tty initialization
1886 * - concurrent tty driver removal w/ lookup
1887 * - concurrent tty removal from driver table
1888 */
1889struct tty_struct *tty_kopen(dev_t device)
1890{
1891 struct tty_struct *tty;
1892 struct tty_driver *driver = NULL;
1893 int index = -1;
1894
1895 mutex_lock(&tty_mutex);
1896 driver = tty_lookup_driver(device, NULL, &index);
1897 if (IS_ERR(driver)) {
1898 mutex_unlock(&tty_mutex);
1899 return ERR_CAST(driver);
1900 }
1901
1902 /* check whether we're reopening an existing tty */
1903 tty = tty_driver_lookup_tty(driver, NULL, index);
1904 if (IS_ERR(tty))
1905 goto out;
1906
1907 if (tty) {
1908 /* drop kref from tty_driver_lookup_tty() */
1909 tty_kref_put(tty);
1910 tty = ERR_PTR(-EBUSY);
1911 } else { /* tty_init_dev returns tty with the tty_lock held */
1912 tty = tty_init_dev(driver, index);
1913 if (IS_ERR(tty))
1914 goto out;
1915 tty_port_set_kopened(tty->port, 1);
1916 }
1917out:
1918 mutex_unlock(&tty_mutex);
1919 tty_driver_kref_put(driver);
1920 return tty;
1921}
1922EXPORT_SYMBOL_GPL(tty_kopen);
1923
1924/**
1925 * tty_open_by_driver - open a tty device
1926 * @device: dev_t of device to open
1927 * @inode: inode of device file
1928 * @filp: file pointer to tty
1929 *
1930 * Performs the driver lookup, checks for a reopen, or otherwise
1931 * performs the first-time tty initialization.
1932 *
1933 * Returns the locked initialized or re-opened &tty_struct
1934 *
1935 * Claims the global tty_mutex to serialize:
1936 * - concurrent first-time tty initialization
1937 * - concurrent tty driver removal w/ lookup
1938 * - concurrent tty removal from driver table
1939 */
1940static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
1941 struct file *filp)
1942{
1943 struct tty_struct *tty;
1944 struct tty_driver *driver = NULL;
1945 int index = -1;
1946 int retval;
1947
1948 mutex_lock(&tty_mutex);
1949 driver = tty_lookup_driver(device, filp, &index);
1950 if (IS_ERR(driver)) {
1951 mutex_unlock(&tty_mutex);
1952 return ERR_CAST(driver);
1953 }
1954
1955 /* check whether we're reopening an existing tty */
1956 tty = tty_driver_lookup_tty(driver, filp, index);
1957 if (IS_ERR(tty)) {
1958 mutex_unlock(&tty_mutex);
1959 goto out;
1960 }
1961
1962 if (tty) {
1963 if (tty_port_kopened(tty->port)) {
1964 tty_kref_put(tty);
1965 mutex_unlock(&tty_mutex);
1966 tty = ERR_PTR(-EBUSY);
1967 goto out;
1968 }
1969 mutex_unlock(&tty_mutex);
1970 retval = tty_lock_interruptible(tty);
1971 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
1972 if (retval) {
1973 if (retval == -EINTR)
1974 retval = -ERESTARTSYS;
1975 tty = ERR_PTR(retval);
1976 goto out;
1977 }
1978 retval = tty_reopen(tty);
1979 if (retval < 0) {
1980 tty_unlock(tty);
1981 tty = ERR_PTR(retval);
1982 }
1983 } else { /* Returns with the tty_lock held for now */
1984 tty = tty_init_dev(driver, index);
1985 mutex_unlock(&tty_mutex);
1986 }
1987out:
1988 tty_driver_kref_put(driver);
1989 return tty;
1990}
1991
1992/**
1993 * tty_open - open a tty device
1994 * @inode: inode of device file
1995 * @filp: file pointer to tty
1996 *
1997 * tty_open and tty_release keep up the tty count that contains the
1998 * number of opens done on a tty. We cannot use the inode-count, as
1999 * different inodes might point to the same tty.
2000 *
2001 * Open-counting is needed for pty masters, as well as for keeping
2002 * track of serial lines: DTR is dropped when the last close happens.
2003 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2004 *
2005 * The termios state of a pty is reset on first open so that
2006 * settings don't persist across reuse.
2007 *
2008 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
2009 * tty->count should protect the rest.
2010 * ->siglock protects ->signal/->sighand
2011 *
2012 * Note: the tty_unlock/lock cases without a ref are only safe due to
2013 * tty_mutex
2014 */
2015
2016static int tty_open(struct inode *inode, struct file *filp)
2017{
2018 struct tty_struct *tty;
2019 int noctty, retval;
2020 dev_t device = inode->i_rdev;
2021 unsigned saved_flags = filp->f_flags;
2022
2023 nonseekable_open(inode, filp);
2024
2025retry_open:
2026 retval = tty_alloc_file(filp);
2027 if (retval)
2028 return -ENOMEM;
2029
2030 tty = tty_open_current_tty(device, filp);
2031 if (!tty)
2032 tty = tty_open_by_driver(device, inode, filp);
2033
2034 if (IS_ERR(tty)) {
2035 tty_free_file(filp);
2036 retval = PTR_ERR(tty);
2037 if (retval != -EAGAIN || signal_pending(current))
2038 return retval;
2039 schedule();
2040 goto retry_open;
2041 }
2042
2043 tty_add_file(tty, filp);
2044
2045 check_tty_count(tty, __func__);
2046 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2047
2048 if (tty->ops->open)
2049 retval = tty->ops->open(tty, filp);
2050 else
2051 retval = -ENODEV;
2052 filp->f_flags = saved_flags;
2053
2054 if (retval) {
2055 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2056
2057 tty_unlock(tty); /* need to call tty_release without BTM */
2058 tty_release(inode, filp);
2059 if (retval != -ERESTARTSYS)
2060 return retval;
2061
2062 if (signal_pending(current))
2063 return retval;
2064
2065 schedule();
2066 /*
2067 * Need to reset f_op in case a hangup happened.
2068 */
2069 if (tty_hung_up_p(filp))
2070 filp->f_op = &tty_fops;
2071 goto retry_open;
2072 }
2073 clear_bit(TTY_HUPPED, &tty->flags);
2074
2075 noctty = (filp->f_flags & O_NOCTTY) ||
2076 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2077 device == MKDEV(TTYAUX_MAJOR, 1) ||
2078 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2079 tty->driver->subtype == PTY_TYPE_MASTER);
2080 if (!noctty)
2081 tty_open_proc_set_tty(filp, tty);
2082 tty_unlock(tty);
2083 return 0;
2084}
2085
2086
2087
2088/**
2089 * tty_poll - check tty status
2090 * @filp: file being polled
2091 * @wait: poll wait structures to update
2092 *
2093 * Call the line discipline polling method to obtain the poll
2094 * status of the device.
2095 *
2096 * Locking: locks called line discipline but ldisc poll method
2097 * may be re-entered freely by other callers.
2098 */
2099
2100static __poll_t tty_poll(struct file *filp, poll_table *wait)
2101{
2102 struct tty_struct *tty = file_tty(filp);
2103 struct tty_ldisc *ld;
2104 __poll_t ret = 0;
2105
2106 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2107 return 0;
2108
2109 ld = tty_ldisc_ref_wait(tty);
2110 if (!ld)
2111 return hung_up_tty_poll(filp, wait);
2112 if (ld->ops->poll)
2113 ret = ld->ops->poll(tty, filp, wait);
2114 tty_ldisc_deref(ld);
2115 return ret;
2116}
2117
2118static int __tty_fasync(int fd, struct file *filp, int on)
2119{
2120 struct tty_struct *tty = file_tty(filp);
2121 unsigned long flags;
2122 int retval = 0;
2123
2124 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2125 goto out;
2126
2127 retval = fasync_helper(fd, filp, on, &tty->fasync);
2128 if (retval <= 0)
2129 goto out;
2130
2131 if (on) {
2132 enum pid_type type;
2133 struct pid *pid;
2134
2135 spin_lock_irqsave(&tty->ctrl_lock, flags);
2136 if (tty->pgrp) {
2137 pid = tty->pgrp;
2138 type = PIDTYPE_PGID;
2139 } else {
2140 pid = task_pid(current);
2141 type = PIDTYPE_TGID;
2142 }
2143 get_pid(pid);
2144 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2145 __f_setown(filp, pid, type, 0);
2146 put_pid(pid);
2147 retval = 0;
2148 }
2149out:
2150 return retval;
2151}
2152
2153static int tty_fasync(int fd, struct file *filp, int on)
2154{
2155 struct tty_struct *tty = file_tty(filp);
2156 int retval = -ENOTTY;
2157
2158 tty_lock(tty);
2159 if (!tty_hung_up_p(filp))
2160 retval = __tty_fasync(fd, filp, on);
2161 tty_unlock(tty);
2162
2163 return retval;
2164}
2165
2166/**
2167 * tiocsti - fake input character
2168 * @tty: tty to fake input into
2169 * @p: pointer to character
2170 *
2171 * Fake input to a tty device. Does the necessary locking and
2172 * input management.
2173 *
2174 * FIXME: does not honour flow control ??
2175 *
2176 * Locking:
2177 * Called functions take tty_ldiscs_lock
2178 * current->signal->tty check is safe without locks
2179 *
2180 * FIXME: may race normal receive processing
2181 */
2182
2183static int tiocsti(struct tty_struct *tty, char __user *p)
2184{
2185 char ch, mbz = 0;
2186 struct tty_ldisc *ld;
2187
2188 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2189 return -EPERM;
2190 if (get_user(ch, p))
2191 return -EFAULT;
2192 tty_audit_tiocsti(tty, ch);
2193 ld = tty_ldisc_ref_wait(tty);
2194 if (!ld)
2195 return -EIO;
2196 if (ld->ops->receive_buf)
2197 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2198 tty_ldisc_deref(ld);
2199 return 0;
2200}
2201
2202/**
2203 * tiocgwinsz - implement window query ioctl
2204 * @tty; tty
2205 * @arg: user buffer for result
2206 *
2207 * Copies the kernel idea of the window size into the user buffer.
2208 *
2209 * Locking: tty->winsize_mutex is taken to ensure the winsize data
2210 * is consistent.
2211 */
2212
2213static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2214{
2215 int err;
2216
2217 mutex_lock(&tty->winsize_mutex);
2218 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2219 mutex_unlock(&tty->winsize_mutex);
2220
2221 return err ? -EFAULT: 0;
2222}
2223
2224/**
2225 * tty_do_resize - resize event
2226 * @tty: tty being resized
2227 * @rows: rows (character)
2228 * @cols: cols (character)
2229 *
2230 * Update the termios variables and send the necessary signals to
2231 * peform a terminal resize correctly
2232 */
2233
2234int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2235{
2236 struct pid *pgrp;
2237
2238 /* Lock the tty */
2239 mutex_lock(&tty->winsize_mutex);
2240 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2241 goto done;
2242
2243 /* Signal the foreground process group */
2244 pgrp = tty_get_pgrp(tty);
2245 if (pgrp)
2246 kill_pgrp(pgrp, SIGWINCH, 1);
2247 put_pid(pgrp);
2248
2249 tty->winsize = *ws;
2250done:
2251 mutex_unlock(&tty->winsize_mutex);
2252 return 0;
2253}
2254EXPORT_SYMBOL(tty_do_resize);
2255
2256/**
2257 * tiocswinsz - implement window size set ioctl
2258 * @tty; tty side of tty
2259 * @arg: user buffer for result
2260 *
2261 * Copies the user idea of the window size to the kernel. Traditionally
2262 * this is just advisory information but for the Linux console it
2263 * actually has driver level meaning and triggers a VC resize.
2264 *
2265 * Locking:
2266 * Driver dependent. The default do_resize method takes the
2267 * tty termios mutex and ctrl_lock. The console takes its own lock
2268 * then calls into the default method.
2269 */
2270
2271static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2272{
2273 struct winsize tmp_ws;
2274 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2275 return -EFAULT;
2276
2277 if (tty->ops->resize)
2278 return tty->ops->resize(tty, &tmp_ws);
2279 else
2280 return tty_do_resize(tty, &tmp_ws);
2281}
2282
2283/**
2284 * tioccons - allow admin to move logical console
2285 * @file: the file to become console
2286 *
2287 * Allow the administrator to move the redirected console device
2288 *
2289 * Locking: uses redirect_lock to guard the redirect information
2290 */
2291
2292static int tioccons(struct file *file)
2293{
2294 if (!capable(CAP_SYS_ADMIN))
2295 return -EPERM;
2296 if (file->f_op->write == redirected_tty_write) {
2297 struct file *f;
2298 spin_lock(&redirect_lock);
2299 f = redirect;
2300 redirect = NULL;
2301 spin_unlock(&redirect_lock);
2302 if (f)
2303 fput(f);
2304 return 0;
2305 }
2306 spin_lock(&redirect_lock);
2307 if (redirect) {
2308 spin_unlock(&redirect_lock);
2309 return -EBUSY;
2310 }
2311 redirect = get_file(file);
2312 spin_unlock(&redirect_lock);
2313 return 0;
2314}
2315
2316/**
2317 * tiocsetd - set line discipline
2318 * @tty: tty device
2319 * @p: pointer to user data
2320 *
2321 * Set the line discipline according to user request.
2322 *
2323 * Locking: see tty_set_ldisc, this function is just a helper
2324 */
2325
2326static int tiocsetd(struct tty_struct *tty, int __user *p)
2327{
2328 int disc;
2329 int ret;
2330
2331 if (get_user(disc, p))
2332 return -EFAULT;
2333
2334 ret = tty_set_ldisc(tty, disc);
2335
2336 return ret;
2337}
2338
2339/**
2340 * tiocgetd - get line discipline
2341 * @tty: tty device
2342 * @p: pointer to user data
2343 *
2344 * Retrieves the line discipline id directly from the ldisc.
2345 *
2346 * Locking: waits for ldisc reference (in case the line discipline
2347 * is changing or the tty is being hungup)
2348 */
2349
2350static int tiocgetd(struct tty_struct *tty, int __user *p)
2351{
2352 struct tty_ldisc *ld;
2353 int ret;
2354
2355 ld = tty_ldisc_ref_wait(tty);
2356 if (!ld)
2357 return -EIO;
2358 ret = put_user(ld->ops->num, p);
2359 tty_ldisc_deref(ld);
2360 return ret;
2361}
2362
2363/**
2364 * send_break - performed time break
2365 * @tty: device to break on
2366 * @duration: timeout in mS
2367 *
2368 * Perform a timed break on hardware that lacks its own driver level
2369 * timed break functionality.
2370 *
2371 * Locking:
2372 * atomic_write_lock serializes
2373 *
2374 */
2375
2376static int send_break(struct tty_struct *tty, unsigned int duration)
2377{
2378 int retval;
2379
2380 if (tty->ops->break_ctl == NULL)
2381 return 0;
2382
2383 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2384 retval = tty->ops->break_ctl(tty, duration);
2385 else {
2386 /* Do the work ourselves */
2387 if (tty_write_lock(tty, 0) < 0)
2388 return -EINTR;
2389 retval = tty->ops->break_ctl(tty, -1);
2390 if (retval)
2391 goto out;
2392 if (!signal_pending(current))
2393 msleep_interruptible(duration);
2394 retval = tty->ops->break_ctl(tty, 0);
2395out:
2396 tty_write_unlock(tty);
2397 if (signal_pending(current))
2398 retval = -EINTR;
2399 }
2400 return retval;
2401}
2402
2403/**
2404 * tty_tiocmget - get modem status
2405 * @tty: tty device
2406 * @file: user file pointer
2407 * @p: pointer to result
2408 *
2409 * Obtain the modem status bits from the tty driver if the feature
2410 * is supported. Return -EINVAL if it is not available.
2411 *
2412 * Locking: none (up to the driver)
2413 */
2414
2415static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2416{
2417 int retval = -EINVAL;
2418
2419 if (tty->ops->tiocmget) {
2420 retval = tty->ops->tiocmget(tty);
2421
2422 if (retval >= 0)
2423 retval = put_user(retval, p);
2424 }
2425 return retval;
2426}
2427
2428/**
2429 * tty_tiocmset - set modem status
2430 * @tty: tty device
2431 * @cmd: command - clear bits, set bits or set all
2432 * @p: pointer to desired bits
2433 *
2434 * Set the modem status bits from the tty driver if the feature
2435 * is supported. Return -EINVAL if it is not available.
2436 *
2437 * Locking: none (up to the driver)
2438 */
2439
2440static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2441 unsigned __user *p)
2442{
2443 int retval;
2444 unsigned int set, clear, val;
2445
2446 if (tty->ops->tiocmset == NULL)
2447 return -EINVAL;
2448
2449 retval = get_user(val, p);
2450 if (retval)
2451 return retval;
2452 set = clear = 0;
2453 switch (cmd) {
2454 case TIOCMBIS:
2455 set = val;
2456 break;
2457 case TIOCMBIC:
2458 clear = val;
2459 break;
2460 case TIOCMSET:
2461 set = val;
2462 clear = ~val;
2463 break;
2464 }
2465 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2466 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2467 return tty->ops->tiocmset(tty, set, clear);
2468}
2469
2470static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2471{
2472 int retval = -EINVAL;
2473 struct serial_icounter_struct icount;
2474 memset(&icount, 0, sizeof(icount));
2475 if (tty->ops->get_icount)
2476 retval = tty->ops->get_icount(tty, &icount);
2477 if (retval != 0)
2478 return retval;
2479 if (copy_to_user(arg, &icount, sizeof(icount)))
2480 return -EFAULT;
2481 return 0;
2482}
2483
2484static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2485{
2486 static DEFINE_RATELIMIT_STATE(depr_flags,
2487 DEFAULT_RATELIMIT_INTERVAL,
2488 DEFAULT_RATELIMIT_BURST);
2489 char comm[TASK_COMM_LEN];
2490 struct serial_struct v;
2491 int flags;
2492
2493 if (copy_from_user(&v, ss, sizeof(struct serial_struct)))
2494 return -EFAULT;
2495
2496 flags = v.flags & ASYNC_DEPRECATED;
2497
2498 if (flags && __ratelimit(&depr_flags))
2499 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2500 __func__, get_task_comm(comm, current), flags);
2501 if (!tty->ops->set_serial)
2502 return -ENOTTY;
2503 return tty->ops->set_serial(tty, &v);
2504}
2505
2506static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2507{
2508 struct serial_struct v;
2509 int err;
2510
2511 memset(&v, 0, sizeof(struct serial_struct));
2512 if (!tty->ops->get_serial)
2513 return -ENOTTY;
2514 err = tty->ops->get_serial(tty, &v);
2515 if (!err && copy_to_user(ss, &v, sizeof(struct serial_struct)))
2516 err = -EFAULT;
2517 return err;
2518}
2519
2520/*
2521 * if pty, return the slave side (real_tty)
2522 * otherwise, return self
2523 */
2524static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2525{
2526 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2527 tty->driver->subtype == PTY_TYPE_MASTER)
2528 tty = tty->link;
2529 return tty;
2530}
2531
2532/*
2533 * Split this up, as gcc can choke on it otherwise..
2534 */
2535long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2536{
2537 struct tty_struct *tty = file_tty(file);
2538 struct tty_struct *real_tty;
2539 void __user *p = (void __user *)arg;
2540 int retval;
2541 struct tty_ldisc *ld;
2542
2543 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2544 return -EINVAL;
2545
2546 real_tty = tty_pair_get_tty(tty);
2547
2548 /*
2549 * Factor out some common prep work
2550 */
2551 switch (cmd) {
2552 case TIOCSETD:
2553 case TIOCSBRK:
2554 case TIOCCBRK:
2555 case TCSBRK:
2556 case TCSBRKP:
2557 retval = tty_check_change(tty);
2558 if (retval)
2559 return retval;
2560 if (cmd != TIOCCBRK) {
2561 tty_wait_until_sent(tty, 0);
2562 if (signal_pending(current))
2563 return -EINTR;
2564 }
2565 break;
2566 }
2567
2568 /*
2569 * Now do the stuff.
2570 */
2571 switch (cmd) {
2572 case TIOCSTI:
2573 return tiocsti(tty, p);
2574 case TIOCGWINSZ:
2575 return tiocgwinsz(real_tty, p);
2576 case TIOCSWINSZ:
2577 return tiocswinsz(real_tty, p);
2578 case TIOCCONS:
2579 return real_tty != tty ? -EINVAL : tioccons(file);
2580 case TIOCEXCL:
2581 set_bit(TTY_EXCLUSIVE, &tty->flags);
2582 return 0;
2583 case TIOCNXCL:
2584 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2585 return 0;
2586 case TIOCGEXCL:
2587 {
2588 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2589 return put_user(excl, (int __user *)p);
2590 }
2591 case TIOCGETD:
2592 return tiocgetd(tty, p);
2593 case TIOCSETD:
2594 return tiocsetd(tty, p);
2595 case TIOCVHANGUP:
2596 if (!capable(CAP_SYS_ADMIN))
2597 return -EPERM;
2598 tty_vhangup(tty);
2599 return 0;
2600 case TIOCGDEV:
2601 {
2602 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2603 return put_user(ret, (unsigned int __user *)p);
2604 }
2605 /*
2606 * Break handling
2607 */
2608 case TIOCSBRK: /* Turn break on, unconditionally */
2609 if (tty->ops->break_ctl)
2610 return tty->ops->break_ctl(tty, -1);
2611 return 0;
2612 case TIOCCBRK: /* Turn break off, unconditionally */
2613 if (tty->ops->break_ctl)
2614 return tty->ops->break_ctl(tty, 0);
2615 return 0;
2616 case TCSBRK: /* SVID version: non-zero arg --> no break */
2617 /* non-zero arg means wait for all output data
2618 * to be sent (performed above) but don't send break.
2619 * This is used by the tcdrain() termios function.
2620 */
2621 if (!arg)
2622 return send_break(tty, 250);
2623 return 0;
2624 case TCSBRKP: /* support for POSIX tcsendbreak() */
2625 return send_break(tty, arg ? arg*100 : 250);
2626
2627 case TIOCMGET:
2628 return tty_tiocmget(tty, p);
2629 case TIOCMSET:
2630 case TIOCMBIC:
2631 case TIOCMBIS:
2632 return tty_tiocmset(tty, cmd, p);
2633 case TIOCGICOUNT:
2634 return tty_tiocgicount(tty, p);
2635 case TCFLSH:
2636 switch (arg) {
2637 case TCIFLUSH:
2638 case TCIOFLUSH:
2639 /* flush tty buffer and allow ldisc to process ioctl */
2640 tty_buffer_flush(tty, NULL);
2641 break;
2642 }
2643 break;
2644 case TIOCSSERIAL:
2645 return tty_tiocsserial(tty, p);
2646 case TIOCGSERIAL:
2647 return tty_tiocgserial(tty, p);
2648 case TIOCGPTPEER:
2649 /* Special because the struct file is needed */
2650 return ptm_open_peer(file, tty, (int)arg);
2651 default:
2652 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2653 if (retval != -ENOIOCTLCMD)
2654 return retval;
2655 }
2656 if (tty->ops->ioctl) {
2657 retval = tty->ops->ioctl(tty, cmd, arg);
2658 if (retval != -ENOIOCTLCMD)
2659 return retval;
2660 }
2661 ld = tty_ldisc_ref_wait(tty);
2662 if (!ld)
2663 return hung_up_tty_ioctl(file, cmd, arg);
2664 retval = -EINVAL;
2665 if (ld->ops->ioctl) {
2666 retval = ld->ops->ioctl(tty, file, cmd, arg);
2667 if (retval == -ENOIOCTLCMD)
2668 retval = -ENOTTY;
2669 }
2670 tty_ldisc_deref(ld);
2671 return retval;
2672}
2673
2674#ifdef CONFIG_COMPAT
2675
2676struct serial_struct32 {
2677 compat_int_t type;
2678 compat_int_t line;
2679 compat_uint_t port;
2680 compat_int_t irq;
2681 compat_int_t flags;
2682 compat_int_t xmit_fifo_size;
2683 compat_int_t custom_divisor;
2684 compat_int_t baud_base;
2685 unsigned short close_delay;
2686 char io_type;
2687 char reserved_char[1];
2688 compat_int_t hub6;
2689 unsigned short closing_wait; /* time to wait before closing */
2690 unsigned short closing_wait2; /* no longer used... */
2691 compat_uint_t iomem_base;
2692 unsigned short iomem_reg_shift;
2693 unsigned int port_high;
2694 /* compat_ulong_t iomap_base FIXME */
2695 compat_int_t reserved[1];
2696};
2697
2698static int compat_tty_tiocsserial(struct tty_struct *tty,
2699 struct serial_struct32 __user *ss)
2700{
2701 static DEFINE_RATELIMIT_STATE(depr_flags,
2702 DEFAULT_RATELIMIT_INTERVAL,
2703 DEFAULT_RATELIMIT_BURST);
2704 char comm[TASK_COMM_LEN];
2705 struct serial_struct32 v32;
2706 struct serial_struct v;
2707 int flags;
2708
2709 if (copy_from_user(&v32, ss, sizeof(struct serial_struct32)))
2710 return -EFAULT;
2711
2712 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2713 v.iomem_base = compat_ptr(v32.iomem_base);
2714 v.iomem_reg_shift = v32.iomem_reg_shift;
2715 v.port_high = v32.port_high;
2716 v.iomap_base = 0;
2717
2718 flags = v.flags & ASYNC_DEPRECATED;
2719
2720 if (flags && __ratelimit(&depr_flags))
2721 pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2722 __func__, get_task_comm(comm, current), flags);
2723 if (!tty->ops->set_serial)
2724 return -ENOTTY;
2725 return tty->ops->set_serial(tty, &v);
2726}
2727
2728static int compat_tty_tiocgserial(struct tty_struct *tty,
2729 struct serial_struct32 __user *ss)
2730{
2731 struct serial_struct32 v32;
2732 struct serial_struct v;
2733 int err;
2734 memset(&v, 0, sizeof(struct serial_struct));
2735
2736 if (!tty->ops->set_serial)
2737 return -ENOTTY;
2738 err = tty->ops->get_serial(tty, &v);
2739 if (!err) {
2740 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2741 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2742 0xfffffff : ptr_to_compat(v.iomem_base);
2743 v32.iomem_reg_shift = v.iomem_reg_shift;
2744 v32.port_high = v.port_high;
2745 if (copy_to_user(ss, &v32, sizeof(struct serial_struct32)))
2746 err = -EFAULT;
2747 }
2748 return err;
2749}
2750static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2751 unsigned long arg)
2752{
2753 struct tty_struct *tty = file_tty(file);
2754 struct tty_ldisc *ld;
2755 int retval = -ENOIOCTLCMD;
2756
2757 switch (cmd) {
2758 case TIOCSTI:
2759 case TIOCGWINSZ:
2760 case TIOCSWINSZ:
2761 case TIOCGEXCL:
2762 case TIOCGETD:
2763 case TIOCSETD:
2764 case TIOCGDEV:
2765 case TIOCMGET:
2766 case TIOCMSET:
2767 case TIOCMBIC:
2768 case TIOCMBIS:
2769 case TIOCGICOUNT:
2770 case TIOCGPGRP:
2771 case TIOCSPGRP:
2772 case TIOCGSID:
2773 case TIOCSERGETLSR:
2774 case TIOCGRS485:
2775 case TIOCSRS485:
2776#ifdef TIOCGETP
2777 case TIOCGETP:
2778 case TIOCSETP:
2779 case TIOCSETN:
2780#endif
2781#ifdef TIOCGETC
2782 case TIOCGETC:
2783 case TIOCSETC:
2784#endif
2785#ifdef TIOCGLTC
2786 case TIOCGLTC:
2787 case TIOCSLTC:
2788#endif
2789 case TCSETSF:
2790 case TCSETSW:
2791 case TCSETS:
2792 case TCGETS:
2793#ifdef TCGETS2
2794 case TCGETS2:
2795 case TCSETSF2:
2796 case TCSETSW2:
2797 case TCSETS2:
2798#endif
2799 case TCGETA:
2800 case TCSETAF:
2801 case TCSETAW:
2802 case TCSETA:
2803 case TIOCGLCKTRMIOS:
2804 case TIOCSLCKTRMIOS:
2805#ifdef TCGETX
2806 case TCGETX:
2807 case TCSETX:
2808 case TCSETXW:
2809 case TCSETXF:
2810#endif
2811 case TIOCGSOFTCAR:
2812 case TIOCSSOFTCAR:
2813 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2814 case TIOCCONS:
2815 case TIOCEXCL:
2816 case TIOCNXCL:
2817 case TIOCVHANGUP:
2818 case TIOCSBRK:
2819 case TIOCCBRK:
2820 case TCSBRK:
2821 case TCSBRKP:
2822 case TCFLSH:
2823 case TIOCGPTPEER:
2824 case TIOCNOTTY:
2825 case TIOCSCTTY:
2826 case TCXONC:
2827 case TIOCMIWAIT:
2828 case TIOCSERCONFIG:
2829 return tty_ioctl(file, cmd, arg);
2830 }
2831
2832 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2833 return -EINVAL;
2834
2835 switch (cmd) {
2836 case TIOCSSERIAL:
2837 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2838 case TIOCGSERIAL:
2839 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2840 }
2841 if (tty->ops->compat_ioctl) {
2842 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2843 if (retval != -ENOIOCTLCMD)
2844 return retval;
2845 }
2846
2847 ld = tty_ldisc_ref_wait(tty);
2848 if (!ld)
2849 return hung_up_tty_compat_ioctl(file, cmd, arg);
2850 if (ld->ops->compat_ioctl)
2851 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2852 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2853 retval = ld->ops->ioctl(tty, file,
2854 (unsigned long)compat_ptr(cmd), arg);
2855 tty_ldisc_deref(ld);
2856
2857 return retval;
2858}
2859#endif
2860
2861static int this_tty(const void *t, struct file *file, unsigned fd)
2862{
2863 if (likely(file->f_op->read != tty_read))
2864 return 0;
2865 return file_tty(file) != t ? 0 : fd + 1;
2866}
2867
2868/*
2869 * This implements the "Secure Attention Key" --- the idea is to
2870 * prevent trojan horses by killing all processes associated with this
2871 * tty when the user hits the "Secure Attention Key". Required for
2872 * super-paranoid applications --- see the Orange Book for more details.
2873 *
2874 * This code could be nicer; ideally it should send a HUP, wait a few
2875 * seconds, then send a INT, and then a KILL signal. But you then
2876 * have to coordinate with the init process, since all processes associated
2877 * with the current tty must be dead before the new getty is allowed
2878 * to spawn.
2879 *
2880 * Now, if it would be correct ;-/ The current code has a nasty hole -
2881 * it doesn't catch files in flight. We may send the descriptor to ourselves
2882 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2883 *
2884 * Nasty bug: do_SAK is being called in interrupt context. This can
2885 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2886 */
2887void __do_SAK(struct tty_struct *tty)
2888{
2889#ifdef TTY_SOFT_SAK
2890 tty_hangup(tty);
2891#else
2892 struct task_struct *g, *p;
2893 struct pid *session;
2894 int i;
2895
2896 if (!tty)
2897 return;
2898 session = tty->session;
2899
2900 tty_ldisc_flush(tty);
2901
2902 tty_driver_flush_buffer(tty);
2903
2904 read_lock(&tasklist_lock);
2905 /* Kill the entire session */
2906 do_each_pid_task(session, PIDTYPE_SID, p) {
2907 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
2908 task_pid_nr(p), p->comm);
2909 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2910 } while_each_pid_task(session, PIDTYPE_SID, p);
2911
2912 /* Now kill any processes that happen to have the tty open */
2913 do_each_thread(g, p) {
2914 if (p->signal->tty == tty) {
2915 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
2916 task_pid_nr(p), p->comm);
2917 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2918 continue;
2919 }
2920 task_lock(p);
2921 i = iterate_fd(p->files, 0, this_tty, tty);
2922 if (i != 0) {
2923 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
2924 task_pid_nr(p), p->comm, i - 1);
2925 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
2926 }
2927 task_unlock(p);
2928 } while_each_thread(g, p);
2929 read_unlock(&tasklist_lock);
2930#endif
2931}
2932
2933static void do_SAK_work(struct work_struct *work)
2934{
2935 struct tty_struct *tty =
2936 container_of(work, struct tty_struct, SAK_work);
2937 __do_SAK(tty);
2938}
2939
2940/*
2941 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2942 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2943 * the values which we write to it will be identical to the values which it
2944 * already has. --akpm
2945 */
2946void do_SAK(struct tty_struct *tty)
2947{
2948 if (!tty)
2949 return;
2950 schedule_work(&tty->SAK_work);
2951}
2952
2953EXPORT_SYMBOL(do_SAK);
2954
2955/* Must put_device() after it's unused! */
2956static struct device *tty_get_device(struct tty_struct *tty)
2957{
2958 dev_t devt = tty_devnum(tty);
2959 return class_find_device_by_devt(tty_class, devt);
2960}
2961
2962
2963/**
2964 * alloc_tty_struct
2965 *
2966 * This subroutine allocates and initializes a tty structure.
2967 *
2968 * Locking: none - tty in question is not exposed at this point
2969 */
2970
2971struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
2972{
2973 struct tty_struct *tty;
2974
2975 tty = kzalloc(sizeof(*tty), GFP_KERNEL);
2976 if (!tty)
2977 return NULL;
2978
2979 kref_init(&tty->kref);
2980 tty->magic = TTY_MAGIC;
2981 if (tty_ldisc_init(tty)) {
2982 kfree(tty);
2983 return NULL;
2984 }
2985 tty->session = NULL;
2986 tty->pgrp = NULL;
2987 mutex_init(&tty->legacy_mutex);
2988 mutex_init(&tty->throttle_mutex);
2989 init_rwsem(&tty->termios_rwsem);
2990 mutex_init(&tty->winsize_mutex);
2991 init_ldsem(&tty->ldisc_sem);
2992 init_waitqueue_head(&tty->write_wait);
2993 init_waitqueue_head(&tty->read_wait);
2994 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2995 mutex_init(&tty->atomic_write_lock);
2996 spin_lock_init(&tty->ctrl_lock);
2997 spin_lock_init(&tty->flow_lock);
2998 spin_lock_init(&tty->files_lock);
2999 INIT_LIST_HEAD(&tty->tty_files);
3000 INIT_WORK(&tty->SAK_work, do_SAK_work);
3001
3002 tty->driver = driver;
3003 tty->ops = driver->ops;
3004 tty->index = idx;
3005 tty_line_name(driver, idx, tty->name);
3006 tty->dev = tty_get_device(tty);
3007
3008 return tty;
3009}
3010
3011/**
3012 * tty_put_char - write one character to a tty
3013 * @tty: tty
3014 * @ch: character
3015 *
3016 * Write one byte to the tty using the provided put_char method
3017 * if present. Returns the number of characters successfully output.
3018 *
3019 * Note: the specific put_char operation in the driver layer may go
3020 * away soon. Don't call it directly, use this method
3021 */
3022
3023int tty_put_char(struct tty_struct *tty, unsigned char ch)
3024{
3025 if (tty->ops->put_char)
3026 return tty->ops->put_char(tty, ch);
3027 return tty->ops->write(tty, &ch, 1);
3028}
3029EXPORT_SYMBOL_GPL(tty_put_char);
3030
3031struct class *tty_class;
3032
3033static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3034 unsigned int index, unsigned int count)
3035{
3036 int err;
3037
3038 /* init here, since reused cdevs cause crashes */
3039 driver->cdevs[index] = cdev_alloc();
3040 if (!driver->cdevs[index])
3041 return -ENOMEM;
3042 driver->cdevs[index]->ops = &tty_fops;
3043 driver->cdevs[index]->owner = driver->owner;
3044 err = cdev_add(driver->cdevs[index], dev, count);
3045 if (err)
3046 kobject_put(&driver->cdevs[index]->kobj);
3047 return err;
3048}
3049
3050/**
3051 * tty_register_device - register a tty device
3052 * @driver: the tty driver that describes the tty device
3053 * @index: the index in the tty driver for this tty device
3054 * @device: a struct device that is associated with this tty device.
3055 * This field is optional, if there is no known struct device
3056 * for this tty device it can be set to NULL safely.
3057 *
3058 * Returns a pointer to the struct device for this tty device
3059 * (or ERR_PTR(-EFOO) on error).
3060 *
3061 * This call is required to be made to register an individual tty device
3062 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3063 * that bit is not set, this function should not be called by a tty
3064 * driver.
3065 *
3066 * Locking: ??
3067 */
3068
3069struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3070 struct device *device)
3071{
3072 return tty_register_device_attr(driver, index, device, NULL, NULL);
3073}
3074EXPORT_SYMBOL(tty_register_device);
3075
3076static void tty_device_create_release(struct device *dev)
3077{
3078 dev_dbg(dev, "releasing...\n");
3079 kfree(dev);
3080}
3081
3082/**
3083 * tty_register_device_attr - register a tty device
3084 * @driver: the tty driver that describes the tty device
3085 * @index: the index in the tty driver for this tty device
3086 * @device: a struct device that is associated with this tty device.
3087 * This field is optional, if there is no known struct device
3088 * for this tty device it can be set to NULL safely.
3089 * @drvdata: Driver data to be set to device.
3090 * @attr_grp: Attribute group to be set on device.
3091 *
3092 * Returns a pointer to the struct device for this tty device
3093 * (or ERR_PTR(-EFOO) on error).
3094 *
3095 * This call is required to be made to register an individual tty device
3096 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3097 * that bit is not set, this function should not be called by a tty
3098 * driver.
3099 *
3100 * Locking: ??
3101 */
3102struct device *tty_register_device_attr(struct tty_driver *driver,
3103 unsigned index, struct device *device,
3104 void *drvdata,
3105 const struct attribute_group **attr_grp)
3106{
3107 char name[64];
3108 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3109 struct ktermios *tp;
3110 struct device *dev;
3111 int retval;
3112
3113 if (index >= driver->num) {
3114 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3115 driver->name, index);
3116 return ERR_PTR(-EINVAL);
3117 }
3118
3119 if (driver->type == TTY_DRIVER_TYPE_PTY)
3120 pty_line_name(driver, index, name);
3121 else
3122 tty_line_name(driver, index, name);
3123
3124 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3125 if (!dev)
3126 return ERR_PTR(-ENOMEM);
3127
3128 dev->devt = devt;
3129 dev->class = tty_class;
3130 dev->parent = device;
3131 dev->release = tty_device_create_release;
3132 dev_set_name(dev, "%s", name);
3133 dev->groups = attr_grp;
3134 dev_set_drvdata(dev, drvdata);
3135
3136 dev_set_uevent_suppress(dev, 1);
3137
3138 retval = device_register(dev);
3139 if (retval)
3140 goto err_put;
3141
3142 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3143 /*
3144 * Free any saved termios data so that the termios state is
3145 * reset when reusing a minor number.
3146 */
3147 tp = driver->termios[index];
3148 if (tp) {
3149 driver->termios[index] = NULL;
3150 kfree(tp);
3151 }
3152
3153 retval = tty_cdev_add(driver, devt, index, 1);
3154 if (retval)
3155 goto err_del;
3156 }
3157
3158 dev_set_uevent_suppress(dev, 0);
3159 kobject_uevent(&dev->kobj, KOBJ_ADD);
3160
3161 return dev;
3162
3163err_del:
3164 device_del(dev);
3165err_put:
3166 put_device(dev);
3167
3168 return ERR_PTR(retval);
3169}
3170EXPORT_SYMBOL_GPL(tty_register_device_attr);
3171
3172/**
3173 * tty_unregister_device - unregister a tty device
3174 * @driver: the tty driver that describes the tty device
3175 * @index: the index in the tty driver for this tty device
3176 *
3177 * If a tty device is registered with a call to tty_register_device() then
3178 * this function must be called when the tty device is gone.
3179 *
3180 * Locking: ??
3181 */
3182
3183void tty_unregister_device(struct tty_driver *driver, unsigned index)
3184{
3185 device_destroy(tty_class,
3186 MKDEV(driver->major, driver->minor_start) + index);
3187 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3188 cdev_del(driver->cdevs[index]);
3189 driver->cdevs[index] = NULL;
3190 }
3191}
3192EXPORT_SYMBOL(tty_unregister_device);
3193
3194/**
3195 * __tty_alloc_driver -- allocate tty driver
3196 * @lines: count of lines this driver can handle at most
3197 * @owner: module which is responsible for this driver
3198 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3199 *
3200 * This should not be called directly, some of the provided macros should be
3201 * used instead. Use IS_ERR and friends on @retval.
3202 */
3203struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3204 unsigned long flags)
3205{
3206 struct tty_driver *driver;
3207 unsigned int cdevs = 1;
3208 int err;
3209
3210 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3211 return ERR_PTR(-EINVAL);
3212
3213 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3214 if (!driver)
3215 return ERR_PTR(-ENOMEM);
3216
3217 kref_init(&driver->kref);
3218 driver->magic = TTY_DRIVER_MAGIC;
3219 driver->num = lines;
3220 driver->owner = owner;
3221 driver->flags = flags;
3222
3223 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3224 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3225 GFP_KERNEL);
3226 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3227 GFP_KERNEL);
3228 if (!driver->ttys || !driver->termios) {
3229 err = -ENOMEM;
3230 goto err_free_all;
3231 }
3232 }
3233
3234 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3235 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3236 GFP_KERNEL);
3237 if (!driver->ports) {
3238 err = -ENOMEM;
3239 goto err_free_all;
3240 }
3241 cdevs = lines;
3242 }
3243
3244 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3245 if (!driver->cdevs) {
3246 err = -ENOMEM;
3247 goto err_free_all;
3248 }
3249
3250 return driver;
3251err_free_all:
3252 kfree(driver->ports);
3253 kfree(driver->ttys);
3254 kfree(driver->termios);
3255 kfree(driver->cdevs);
3256 kfree(driver);
3257 return ERR_PTR(err);
3258}
3259EXPORT_SYMBOL(__tty_alloc_driver);
3260
3261static void destruct_tty_driver(struct kref *kref)
3262{
3263 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3264 int i;
3265 struct ktermios *tp;
3266
3267 if (driver->flags & TTY_DRIVER_INSTALLED) {
3268 for (i = 0; i < driver->num; i++) {
3269 tp = driver->termios[i];
3270 if (tp) {
3271 driver->termios[i] = NULL;
3272 kfree(tp);
3273 }
3274 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3275 tty_unregister_device(driver, i);
3276 }
3277 proc_tty_unregister_driver(driver);
3278 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3279 cdev_del(driver->cdevs[0]);
3280 }
3281 kfree(driver->cdevs);
3282 kfree(driver->ports);
3283 kfree(driver->termios);
3284 kfree(driver->ttys);
3285 kfree(driver);
3286}
3287
3288void tty_driver_kref_put(struct tty_driver *driver)
3289{
3290 kref_put(&driver->kref, destruct_tty_driver);
3291}
3292EXPORT_SYMBOL(tty_driver_kref_put);
3293
3294void tty_set_operations(struct tty_driver *driver,
3295 const struct tty_operations *op)
3296{
3297 driver->ops = op;
3298};
3299EXPORT_SYMBOL(tty_set_operations);
3300
3301void put_tty_driver(struct tty_driver *d)
3302{
3303 tty_driver_kref_put(d);
3304}
3305EXPORT_SYMBOL(put_tty_driver);
3306
3307/*
3308 * Called by a tty driver to register itself.
3309 */
3310int tty_register_driver(struct tty_driver *driver)
3311{
3312 int error;
3313 int i;
3314 dev_t dev;
3315 struct device *d;
3316
3317 if (!driver->major) {
3318 error = alloc_chrdev_region(&dev, driver->minor_start,
3319 driver->num, driver->name);
3320 if (!error) {
3321 driver->major = MAJOR(dev);
3322 driver->minor_start = MINOR(dev);
3323 }
3324 } else {
3325 dev = MKDEV(driver->major, driver->minor_start);
3326 error = register_chrdev_region(dev, driver->num, driver->name);
3327 }
3328 if (error < 0)
3329 goto err;
3330
3331 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3332 error = tty_cdev_add(driver, dev, 0, driver->num);
3333 if (error)
3334 goto err_unreg_char;
3335 }
3336
3337 mutex_lock(&tty_mutex);
3338 list_add(&driver->tty_drivers, &tty_drivers);
3339 mutex_unlock(&tty_mutex);
3340
3341 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3342 for (i = 0; i < driver->num; i++) {
3343 d = tty_register_device(driver, i, NULL);
3344 if (IS_ERR(d)) {
3345 error = PTR_ERR(d);
3346 goto err_unreg_devs;
3347 }
3348 }
3349 }
3350 proc_tty_register_driver(driver);
3351 driver->flags |= TTY_DRIVER_INSTALLED;
3352 return 0;
3353
3354err_unreg_devs:
3355 for (i--; i >= 0; i--)
3356 tty_unregister_device(driver, i);
3357
3358 mutex_lock(&tty_mutex);
3359 list_del(&driver->tty_drivers);
3360 mutex_unlock(&tty_mutex);
3361
3362err_unreg_char:
3363 unregister_chrdev_region(dev, driver->num);
3364err:
3365 return error;
3366}
3367EXPORT_SYMBOL(tty_register_driver);
3368
3369/*
3370 * Called by a tty driver to unregister itself.
3371 */
3372int tty_unregister_driver(struct tty_driver *driver)
3373{
3374#if 0
3375 /* FIXME */
3376 if (driver->refcount)
3377 return -EBUSY;
3378#endif
3379 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3380 driver->num);
3381 mutex_lock(&tty_mutex);
3382 list_del(&driver->tty_drivers);
3383 mutex_unlock(&tty_mutex);
3384 return 0;
3385}
3386
3387EXPORT_SYMBOL(tty_unregister_driver);
3388
3389dev_t tty_devnum(struct tty_struct *tty)
3390{
3391 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3392}
3393EXPORT_SYMBOL(tty_devnum);
3394
3395void tty_default_fops(struct file_operations *fops)
3396{
3397 *fops = tty_fops;
3398}
3399
3400static char *tty_devnode(struct device *dev, umode_t *mode)
3401{
3402 if (!mode)
3403 return NULL;
3404 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3405 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3406 *mode = 0666;
3407 return NULL;
3408}
3409
3410static int __init tty_class_init(void)
3411{
3412 tty_class = class_create(THIS_MODULE, "tty");
3413 if (IS_ERR(tty_class))
3414 return PTR_ERR(tty_class);
3415 tty_class->devnode = tty_devnode;
3416 return 0;
3417}
3418
3419postcore_initcall(tty_class_init);
3420
3421/* 3/2004 jmc: why do these devices exist? */
3422static struct cdev tty_cdev, console_cdev;
3423
3424static ssize_t show_cons_active(struct device *dev,
3425 struct device_attribute *attr, char *buf)
3426{
3427 struct console *cs[16];
3428 int i = 0;
3429 struct console *c;
3430 ssize_t count = 0;
3431
3432 console_lock();
3433 for_each_console(c) {
3434 if (!c->device)
3435 continue;
3436 if (!c->write)
3437 continue;
3438 if ((c->flags & CON_ENABLED) == 0)
3439 continue;
3440 cs[i++] = c;
3441 if (i >= ARRAY_SIZE(cs))
3442 break;
3443 }
3444 while (i--) {
3445 int index = cs[i]->index;
3446 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3447
3448 /* don't resolve tty0 as some programs depend on it */
3449 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3450 count += tty_line_name(drv, index, buf + count);
3451 else
3452 count += sprintf(buf + count, "%s%d",
3453 cs[i]->name, cs[i]->index);
3454
3455 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3456 }
3457 console_unlock();
3458
3459 return count;
3460}
3461static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3462
3463static struct attribute *cons_dev_attrs[] = {
3464 &dev_attr_active.attr,
3465 NULL
3466};
3467
3468ATTRIBUTE_GROUPS(cons_dev);
3469
3470static struct device *consdev;
3471
3472void console_sysfs_notify(void)
3473{
3474 if (consdev)
3475 sysfs_notify(&consdev->kobj, NULL, "active");
3476}
3477
3478/*
3479 * Ok, now we can initialize the rest of the tty devices and can count
3480 * on memory allocations, interrupts etc..
3481 */
3482int __init tty_init(void)
3483{
3484 tty_sysctl_init();
3485 cdev_init(&tty_cdev, &tty_fops);
3486 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3487 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3488 panic("Couldn't register /dev/tty driver\n");
3489 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3490
3491 cdev_init(&console_cdev, &console_fops);
3492 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3493 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3494 panic("Couldn't register /dev/console driver\n");
3495 consdev = device_create_with_groups(tty_class, NULL,
3496 MKDEV(TTYAUX_MAJOR, 1), NULL,
3497 cons_dev_groups, "console");
3498 if (IS_ERR(consdev))
3499 consdev = NULL;
3500
3501#ifdef CONFIG_VT
3502 vty_init(&console_fops);
3503#endif
3504 return 0;
3505}
3506