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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#include <asm/system.h>
101
102#include <linux/kbd_kern.h>
103#include <linux/vt_kern.h>
104#include <linux/selection.h>
105
106#include <linux/kmod.h>
107#include <linux/nsproxy.h>
108
109#undef TTY_DEBUG_HANGUP
110
111#define TTY_PARANOIA_CHECK 1
112#define CHECK_TTY_COUNT 1
113
114struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
115 .c_iflag = ICRNL | IXON,
116 .c_oflag = OPOST | ONLCR,
117 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
118 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
119 ECHOCTL | ECHOKE | IEXTEN,
120 .c_cc = INIT_C_CC,
121 .c_ispeed = 38400,
122 .c_ospeed = 38400
123};
124
125EXPORT_SYMBOL(tty_std_termios);
126
127/* This list gets poked at by procfs and various bits of boot up code. This
128 could do with some rationalisation such as pulling the tty proc function
129 into this file */
130
131LIST_HEAD(tty_drivers); /* linked list of tty drivers */
132
133/* Mutex to protect creating and releasing a tty. This is shared with
134 vt.c for deeply disgusting hack reasons */
135DEFINE_MUTEX(tty_mutex);
136EXPORT_SYMBOL(tty_mutex);
137
138/* Spinlock to protect the tty->tty_files list */
139DEFINE_SPINLOCK(tty_files_lock);
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);
157static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
158static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
159
160/**
161 * alloc_tty_struct - allocate a tty object
162 *
163 * Return a new empty tty structure. The data fields have not
164 * been initialized in any way but has been zeroed
165 *
166 * Locking: none
167 */
168
169struct tty_struct *alloc_tty_struct(void)
170{
171 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
172}
173
174/**
175 * free_tty_struct - free a disused tty
176 * @tty: tty struct to free
177 *
178 * Free the write buffers, tty queue and tty memory itself.
179 *
180 * Locking: none. Must be called after tty is definitely unused
181 */
182
183void free_tty_struct(struct tty_struct *tty)
184{
185 if (tty->dev)
186 put_device(tty->dev);
187 kfree(tty->write_buf);
188 tty_buffer_free_all(tty);
189 kfree(tty);
190}
191
192static inline struct tty_struct *file_tty(struct file *file)
193{
194 return ((struct tty_file_private *)file->private_data)->tty;
195}
196
197/* Associate a new file with the tty structure */
198int tty_add_file(struct tty_struct *tty, struct file *file)
199{
200 struct tty_file_private *priv;
201
202 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
203 if (!priv)
204 return -ENOMEM;
205
206 priv->tty = tty;
207 priv->file = file;
208 file->private_data = priv;
209
210 spin_lock(&tty_files_lock);
211 list_add(&priv->list, &tty->tty_files);
212 spin_unlock(&tty_files_lock);
213
214 return 0;
215}
216
217/* Delete file from its tty */
218void tty_del_file(struct file *file)
219{
220 struct tty_file_private *priv = file->private_data;
221
222 spin_lock(&tty_files_lock);
223 list_del(&priv->list);
224 spin_unlock(&tty_files_lock);
225 file->private_data = NULL;
226 kfree(priv);
227}
228
229
230#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
231
232/**
233 * tty_name - return tty naming
234 * @tty: tty structure
235 * @buf: buffer for output
236 *
237 * Convert a tty structure into a name. The name reflects the kernel
238 * naming policy and if udev is in use may not reflect user space
239 *
240 * Locking: none
241 */
242
243char *tty_name(struct tty_struct *tty, char *buf)
244{
245 if (!tty) /* Hmm. NULL pointer. That's fun. */
246 strcpy(buf, "NULL tty");
247 else
248 strcpy(buf, tty->name);
249 return buf;
250}
251
252EXPORT_SYMBOL(tty_name);
253
254int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
255 const char *routine)
256{
257#ifdef TTY_PARANOIA_CHECK
258 if (!tty) {
259 printk(KERN_WARNING
260 "null TTY for (%d:%d) in %s\n",
261 imajor(inode), iminor(inode), routine);
262 return 1;
263 }
264 if (tty->magic != TTY_MAGIC) {
265 printk(KERN_WARNING
266 "bad magic number for tty struct (%d:%d) in %s\n",
267 imajor(inode), iminor(inode), routine);
268 return 1;
269 }
270#endif
271 return 0;
272}
273
274static int check_tty_count(struct tty_struct *tty, const char *routine)
275{
276#ifdef CHECK_TTY_COUNT
277 struct list_head *p;
278 int count = 0;
279
280 spin_lock(&tty_files_lock);
281 list_for_each(p, &tty->tty_files) {
282 count++;
283 }
284 spin_unlock(&tty_files_lock);
285 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
286 tty->driver->subtype == PTY_TYPE_SLAVE &&
287 tty->link && tty->link->count)
288 count++;
289 if (tty->count != count) {
290 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
291 "!= #fd's(%d) in %s\n",
292 tty->name, tty->count, count, routine);
293 return count;
294 }
295#endif
296 return 0;
297}
298
299/**
300 * get_tty_driver - find device of a tty
301 * @dev_t: device identifier
302 * @index: returns the index of the tty
303 *
304 * This routine returns a tty driver structure, given a device number
305 * and also passes back the index number.
306 *
307 * Locking: caller must hold tty_mutex
308 */
309
310static struct tty_driver *get_tty_driver(dev_t device, int *index)
311{
312 struct tty_driver *p;
313
314 list_for_each_entry(p, &tty_drivers, tty_drivers) {
315 dev_t base = MKDEV(p->major, p->minor_start);
316 if (device < base || device >= base + p->num)
317 continue;
318 *index = device - base;
319 return tty_driver_kref_get(p);
320 }
321 return NULL;
322}
323
324#ifdef CONFIG_CONSOLE_POLL
325
326/**
327 * tty_find_polling_driver - find device of a polled tty
328 * @name: name string to match
329 * @line: pointer to resulting tty line nr
330 *
331 * This routine returns a tty driver structure, given a name
332 * and the condition that the tty driver is capable of polled
333 * operation.
334 */
335struct tty_driver *tty_find_polling_driver(char *name, int *line)
336{
337 struct tty_driver *p, *res = NULL;
338 int tty_line = 0;
339 int len;
340 char *str, *stp;
341
342 for (str = name; *str; str++)
343 if ((*str >= '0' && *str <= '9') || *str == ',')
344 break;
345 if (!*str)
346 return NULL;
347
348 len = str - name;
349 tty_line = simple_strtoul(str, &str, 10);
350
351 mutex_lock(&tty_mutex);
352 /* Search through the tty devices to look for a match */
353 list_for_each_entry(p, &tty_drivers, tty_drivers) {
354 if (strncmp(name, p->name, len) != 0)
355 continue;
356 stp = str;
357 if (*stp == ',')
358 stp++;
359 if (*stp == '\0')
360 stp = NULL;
361
362 if (tty_line >= 0 && tty_line < p->num && p->ops &&
363 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
364 res = tty_driver_kref_get(p);
365 *line = tty_line;
366 break;
367 }
368 }
369 mutex_unlock(&tty_mutex);
370
371 return res;
372}
373EXPORT_SYMBOL_GPL(tty_find_polling_driver);
374#endif
375
376/**
377 * tty_check_change - check for POSIX terminal changes
378 * @tty: tty to check
379 *
380 * If we try to write to, or set the state of, a terminal and we're
381 * not in the foreground, send a SIGTTOU. If the signal is blocked or
382 * ignored, go ahead and perform the operation. (POSIX 7.2)
383 *
384 * Locking: ctrl_lock
385 */
386
387int tty_check_change(struct tty_struct *tty)
388{
389 unsigned long flags;
390 int ret = 0;
391
392 if (current->signal->tty != tty)
393 return 0;
394
395 spin_lock_irqsave(&tty->ctrl_lock, flags);
396
397 if (!tty->pgrp) {
398 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
399 goto out_unlock;
400 }
401 if (task_pgrp(current) == tty->pgrp)
402 goto out_unlock;
403 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
404 if (is_ignored(SIGTTOU))
405 goto out;
406 if (is_current_pgrp_orphaned()) {
407 ret = -EIO;
408 goto out;
409 }
410 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
411 set_thread_flag(TIF_SIGPENDING);
412 ret = -ERESTARTSYS;
413out:
414 return ret;
415out_unlock:
416 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
417 return ret;
418}
419
420EXPORT_SYMBOL(tty_check_change);
421
422static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
423 size_t count, loff_t *ppos)
424{
425 return 0;
426}
427
428static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
429 size_t count, loff_t *ppos)
430{
431 return -EIO;
432}
433
434/* No kernel lock held - none needed ;) */
435static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
436{
437 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
438}
439
440static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
441 unsigned long arg)
442{
443 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
444}
445
446static long hung_up_tty_compat_ioctl(struct file *file,
447 unsigned int cmd, unsigned long arg)
448{
449 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
450}
451
452static const struct file_operations tty_fops = {
453 .llseek = no_llseek,
454 .read = tty_read,
455 .write = tty_write,
456 .poll = tty_poll,
457 .unlocked_ioctl = tty_ioctl,
458 .compat_ioctl = tty_compat_ioctl,
459 .open = tty_open,
460 .release = tty_release,
461 .fasync = tty_fasync,
462};
463
464static const struct file_operations console_fops = {
465 .llseek = no_llseek,
466 .read = tty_read,
467 .write = redirected_tty_write,
468 .poll = tty_poll,
469 .unlocked_ioctl = tty_ioctl,
470 .compat_ioctl = tty_compat_ioctl,
471 .open = tty_open,
472 .release = tty_release,
473 .fasync = tty_fasync,
474};
475
476static const struct file_operations hung_up_tty_fops = {
477 .llseek = no_llseek,
478 .read = hung_up_tty_read,
479 .write = hung_up_tty_write,
480 .poll = hung_up_tty_poll,
481 .unlocked_ioctl = hung_up_tty_ioctl,
482 .compat_ioctl = hung_up_tty_compat_ioctl,
483 .release = tty_release,
484};
485
486static DEFINE_SPINLOCK(redirect_lock);
487static struct file *redirect;
488
489/**
490 * tty_wakeup - request more data
491 * @tty: terminal
492 *
493 * Internal and external helper for wakeups of tty. This function
494 * informs the line discipline if present that the driver is ready
495 * to receive more output data.
496 */
497
498void tty_wakeup(struct tty_struct *tty)
499{
500 struct tty_ldisc *ld;
501
502 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
503 ld = tty_ldisc_ref(tty);
504 if (ld) {
505 if (ld->ops->write_wakeup)
506 ld->ops->write_wakeup(tty);
507 tty_ldisc_deref(ld);
508 }
509 }
510 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
511}
512
513EXPORT_SYMBOL_GPL(tty_wakeup);
514
515/**
516 * __tty_hangup - actual handler for hangup events
517 * @work: tty device
518 *
519 * This can be called by the "eventd" kernel thread. That is process
520 * synchronous but doesn't hold any locks, so we need to make sure we
521 * have the appropriate locks for what we're doing.
522 *
523 * The hangup event clears any pending redirections onto the hung up
524 * device. It ensures future writes will error and it does the needed
525 * line discipline hangup and signal delivery. The tty object itself
526 * remains intact.
527 *
528 * Locking:
529 * BTM
530 * redirect lock for undoing redirection
531 * file list lock for manipulating list of ttys
532 * tty_ldisc_lock from called functions
533 * termios_mutex resetting termios data
534 * tasklist_lock to walk task list for hangup event
535 * ->siglock to protect ->signal/->sighand
536 */
537void __tty_hangup(struct tty_struct *tty)
538{
539 struct file *cons_filp = NULL;
540 struct file *filp, *f = NULL;
541 struct task_struct *p;
542 struct tty_file_private *priv;
543 int closecount = 0, n;
544 unsigned long flags;
545 int refs = 0;
546
547 if (!tty)
548 return;
549
550
551 spin_lock(&redirect_lock);
552 if (redirect && file_tty(redirect) == tty) {
553 f = redirect;
554 redirect = NULL;
555 }
556 spin_unlock(&redirect_lock);
557
558 tty_lock();
559
560 /* some functions below drop BTM, so we need this bit */
561 set_bit(TTY_HUPPING, &tty->flags);
562
563 /* inuse_filps is protected by the single tty lock,
564 this really needs to change if we want to flush the
565 workqueue with the lock held */
566 check_tty_count(tty, "tty_hangup");
567
568 spin_lock(&tty_files_lock);
569 /* This breaks for file handles being sent over AF_UNIX sockets ? */
570 list_for_each_entry(priv, &tty->tty_files, list) {
571 filp = priv->file;
572 if (filp->f_op->write == redirected_tty_write)
573 cons_filp = filp;
574 if (filp->f_op->write != tty_write)
575 continue;
576 closecount++;
577 __tty_fasync(-1, filp, 0); /* can't block */
578 filp->f_op = &hung_up_tty_fops;
579 }
580 spin_unlock(&tty_files_lock);
581
582 /*
583 * it drops BTM and thus races with reopen
584 * we protect the race by TTY_HUPPING
585 */
586 tty_ldisc_hangup(tty);
587
588 read_lock(&tasklist_lock);
589 if (tty->session) {
590 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
591 spin_lock_irq(&p->sighand->siglock);
592 if (p->signal->tty == tty) {
593 p->signal->tty = NULL;
594 /* We defer the dereferences outside fo
595 the tasklist lock */
596 refs++;
597 }
598 if (!p->signal->leader) {
599 spin_unlock_irq(&p->sighand->siglock);
600 continue;
601 }
602 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
603 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
604 put_pid(p->signal->tty_old_pgrp); /* A noop */
605 spin_lock_irqsave(&tty->ctrl_lock, flags);
606 if (tty->pgrp)
607 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
608 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
609 spin_unlock_irq(&p->sighand->siglock);
610 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
611 }
612 read_unlock(&tasklist_lock);
613
614 spin_lock_irqsave(&tty->ctrl_lock, flags);
615 clear_bit(TTY_THROTTLED, &tty->flags);
616 clear_bit(TTY_PUSH, &tty->flags);
617 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
618 put_pid(tty->session);
619 put_pid(tty->pgrp);
620 tty->session = NULL;
621 tty->pgrp = NULL;
622 tty->ctrl_status = 0;
623 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
624
625 /* Account for the p->signal references we killed */
626 while (refs--)
627 tty_kref_put(tty);
628
629 /*
630 * If one of the devices matches a console pointer, we
631 * cannot just call hangup() because that will cause
632 * tty->count and state->count to go out of sync.
633 * So we just call close() the right number of times.
634 */
635 if (cons_filp) {
636 if (tty->ops->close)
637 for (n = 0; n < closecount; n++)
638 tty->ops->close(tty, cons_filp);
639 } else if (tty->ops->hangup)
640 (tty->ops->hangup)(tty);
641 /*
642 * We don't want to have driver/ldisc interactions beyond
643 * the ones we did here. The driver layer expects no
644 * calls after ->hangup() from the ldisc side. However we
645 * can't yet guarantee all that.
646 */
647 set_bit(TTY_HUPPED, &tty->flags);
648 clear_bit(TTY_HUPPING, &tty->flags);
649 tty_ldisc_enable(tty);
650
651 tty_unlock();
652
653 if (f)
654 fput(f);
655}
656
657static void do_tty_hangup(struct work_struct *work)
658{
659 struct tty_struct *tty =
660 container_of(work, struct tty_struct, hangup_work);
661
662 __tty_hangup(tty);
663}
664
665/**
666 * tty_hangup - trigger a hangup event
667 * @tty: tty to hangup
668 *
669 * A carrier loss (virtual or otherwise) has occurred on this like
670 * schedule a hangup sequence to run after this event.
671 */
672
673void tty_hangup(struct tty_struct *tty)
674{
675#ifdef TTY_DEBUG_HANGUP
676 char buf[64];
677 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
678#endif
679 schedule_work(&tty->hangup_work);
680}
681
682EXPORT_SYMBOL(tty_hangup);
683
684/**
685 * tty_vhangup - process vhangup
686 * @tty: tty to hangup
687 *
688 * The user has asked via system call for the terminal to be hung up.
689 * We do this synchronously so that when the syscall returns the process
690 * is complete. That guarantee is necessary for security reasons.
691 */
692
693void tty_vhangup(struct tty_struct *tty)
694{
695#ifdef TTY_DEBUG_HANGUP
696 char buf[64];
697
698 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
699#endif
700 __tty_hangup(tty);
701}
702
703EXPORT_SYMBOL(tty_vhangup);
704
705
706/**
707 * tty_vhangup_self - process vhangup for own ctty
708 *
709 * Perform a vhangup on the current controlling tty
710 */
711
712void tty_vhangup_self(void)
713{
714 struct tty_struct *tty;
715
716 tty = get_current_tty();
717 if (tty) {
718 tty_vhangup(tty);
719 tty_kref_put(tty);
720 }
721}
722
723/**
724 * tty_hung_up_p - was tty hung up
725 * @filp: file pointer of tty
726 *
727 * Return true if the tty has been subject to a vhangup or a carrier
728 * loss
729 */
730
731int tty_hung_up_p(struct file *filp)
732{
733 return (filp->f_op == &hung_up_tty_fops);
734}
735
736EXPORT_SYMBOL(tty_hung_up_p);
737
738static void session_clear_tty(struct pid *session)
739{
740 struct task_struct *p;
741 do_each_pid_task(session, PIDTYPE_SID, p) {
742 proc_clear_tty(p);
743 } while_each_pid_task(session, PIDTYPE_SID, p);
744}
745
746/**
747 * disassociate_ctty - disconnect controlling tty
748 * @on_exit: true if exiting so need to "hang up" the session
749 *
750 * This function is typically called only by the session leader, when
751 * it wants to disassociate itself from its controlling tty.
752 *
753 * It performs the following functions:
754 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
755 * (2) Clears the tty from being controlling the session
756 * (3) Clears the controlling tty for all processes in the
757 * session group.
758 *
759 * The argument on_exit is set to 1 if called when a process is
760 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
761 *
762 * Locking:
763 * BTM is taken for hysterical raisins, and held when
764 * called from no_tty().
765 * tty_mutex is taken to protect tty
766 * ->siglock is taken to protect ->signal/->sighand
767 * tasklist_lock is taken to walk process list for sessions
768 * ->siglock is taken to protect ->signal/->sighand
769 */
770
771void disassociate_ctty(int on_exit)
772{
773 struct tty_struct *tty;
774 struct pid *tty_pgrp = NULL;
775
776 if (!current->signal->leader)
777 return;
778
779 tty = get_current_tty();
780 if (tty) {
781 tty_pgrp = get_pid(tty->pgrp);
782 if (on_exit) {
783 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
784 tty_vhangup(tty);
785 }
786 tty_kref_put(tty);
787 } else if (on_exit) {
788 struct pid *old_pgrp;
789 spin_lock_irq(¤t->sighand->siglock);
790 old_pgrp = current->signal->tty_old_pgrp;
791 current->signal->tty_old_pgrp = NULL;
792 spin_unlock_irq(¤t->sighand->siglock);
793 if (old_pgrp) {
794 kill_pgrp(old_pgrp, SIGHUP, on_exit);
795 kill_pgrp(old_pgrp, SIGCONT, on_exit);
796 put_pid(old_pgrp);
797 }
798 return;
799 }
800 if (tty_pgrp) {
801 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
802 if (!on_exit)
803 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
804 put_pid(tty_pgrp);
805 }
806
807 spin_lock_irq(¤t->sighand->siglock);
808 put_pid(current->signal->tty_old_pgrp);
809 current->signal->tty_old_pgrp = NULL;
810 spin_unlock_irq(¤t->sighand->siglock);
811
812 tty = get_current_tty();
813 if (tty) {
814 unsigned long flags;
815 spin_lock_irqsave(&tty->ctrl_lock, flags);
816 put_pid(tty->session);
817 put_pid(tty->pgrp);
818 tty->session = NULL;
819 tty->pgrp = NULL;
820 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
821 tty_kref_put(tty);
822 } else {
823#ifdef TTY_DEBUG_HANGUP
824 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
825 " = NULL", tty);
826#endif
827 }
828
829 /* Now clear signal->tty under the lock */
830 read_lock(&tasklist_lock);
831 session_clear_tty(task_session(current));
832 read_unlock(&tasklist_lock);
833}
834
835/**
836 *
837 * no_tty - Ensure the current process does not have a controlling tty
838 */
839void no_tty(void)
840{
841 struct task_struct *tsk = current;
842 tty_lock();
843 disassociate_ctty(0);
844 tty_unlock();
845 proc_clear_tty(tsk);
846}
847
848
849/**
850 * stop_tty - propagate flow control
851 * @tty: tty to stop
852 *
853 * Perform flow control to the driver. For PTY/TTY pairs we
854 * must also propagate the TIOCKPKT status. May be called
855 * on an already stopped device and will not re-call the driver
856 * method.
857 *
858 * This functionality is used by both the line disciplines for
859 * halting incoming flow and by the driver. It may therefore be
860 * called from any context, may be under the tty atomic_write_lock
861 * but not always.
862 *
863 * Locking:
864 * Uses the tty control lock internally
865 */
866
867void stop_tty(struct tty_struct *tty)
868{
869 unsigned long flags;
870 spin_lock_irqsave(&tty->ctrl_lock, flags);
871 if (tty->stopped) {
872 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
873 return;
874 }
875 tty->stopped = 1;
876 if (tty->link && tty->link->packet) {
877 tty->ctrl_status &= ~TIOCPKT_START;
878 tty->ctrl_status |= TIOCPKT_STOP;
879 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
880 }
881 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
882 if (tty->ops->stop)
883 (tty->ops->stop)(tty);
884}
885
886EXPORT_SYMBOL(stop_tty);
887
888/**
889 * start_tty - propagate flow control
890 * @tty: tty to start
891 *
892 * Start a tty that has been stopped if at all possible. Perform
893 * any necessary wakeups and propagate the TIOCPKT status. If this
894 * is the tty was previous stopped and is being started then the
895 * driver start method is invoked and the line discipline woken.
896 *
897 * Locking:
898 * ctrl_lock
899 */
900
901void start_tty(struct tty_struct *tty)
902{
903 unsigned long flags;
904 spin_lock_irqsave(&tty->ctrl_lock, flags);
905 if (!tty->stopped || tty->flow_stopped) {
906 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
907 return;
908 }
909 tty->stopped = 0;
910 if (tty->link && tty->link->packet) {
911 tty->ctrl_status &= ~TIOCPKT_STOP;
912 tty->ctrl_status |= TIOCPKT_START;
913 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
914 }
915 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
916 if (tty->ops->start)
917 (tty->ops->start)(tty);
918 /* If we have a running line discipline it may need kicking */
919 tty_wakeup(tty);
920}
921
922EXPORT_SYMBOL(start_tty);
923
924/**
925 * tty_read - read method for tty device files
926 * @file: pointer to tty file
927 * @buf: user buffer
928 * @count: size of user buffer
929 * @ppos: unused
930 *
931 * Perform the read system call function on this terminal device. Checks
932 * for hung up devices before calling the line discipline method.
933 *
934 * Locking:
935 * Locks the line discipline internally while needed. Multiple
936 * read calls may be outstanding in parallel.
937 */
938
939static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
940 loff_t *ppos)
941{
942 int i;
943 struct inode *inode = file->f_path.dentry->d_inode;
944 struct tty_struct *tty = file_tty(file);
945 struct tty_ldisc *ld;
946
947 if (tty_paranoia_check(tty, inode, "tty_read"))
948 return -EIO;
949 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
950 return -EIO;
951
952 /* We want to wait for the line discipline to sort out in this
953 situation */
954 ld = tty_ldisc_ref_wait(tty);
955 if (ld->ops->read)
956 i = (ld->ops->read)(tty, file, buf, count);
957 else
958 i = -EIO;
959 tty_ldisc_deref(ld);
960 if (i > 0)
961 inode->i_atime = current_fs_time(inode->i_sb);
962 return i;
963}
964
965void tty_write_unlock(struct tty_struct *tty)
966 __releases(&tty->atomic_write_lock)
967{
968 mutex_unlock(&tty->atomic_write_lock);
969 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
970}
971
972int tty_write_lock(struct tty_struct *tty, int ndelay)
973 __acquires(&tty->atomic_write_lock)
974{
975 if (!mutex_trylock(&tty->atomic_write_lock)) {
976 if (ndelay)
977 return -EAGAIN;
978 if (mutex_lock_interruptible(&tty->atomic_write_lock))
979 return -ERESTARTSYS;
980 }
981 return 0;
982}
983
984/*
985 * Split writes up in sane blocksizes to avoid
986 * denial-of-service type attacks
987 */
988static inline ssize_t do_tty_write(
989 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
990 struct tty_struct *tty,
991 struct file *file,
992 const char __user *buf,
993 size_t count)
994{
995 ssize_t ret, written = 0;
996 unsigned int chunk;
997
998 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
999 if (ret < 0)
1000 return ret;
1001
1002 /*
1003 * We chunk up writes into a temporary buffer. This
1004 * simplifies low-level drivers immensely, since they
1005 * don't have locking issues and user mode accesses.
1006 *
1007 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1008 * big chunk-size..
1009 *
1010 * The default chunk-size is 2kB, because the NTTY
1011 * layer has problems with bigger chunks. It will
1012 * claim to be able to handle more characters than
1013 * it actually does.
1014 *
1015 * FIXME: This can probably go away now except that 64K chunks
1016 * are too likely to fail unless switched to vmalloc...
1017 */
1018 chunk = 2048;
1019 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1020 chunk = 65536;
1021 if (count < chunk)
1022 chunk = count;
1023
1024 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1025 if (tty->write_cnt < chunk) {
1026 unsigned char *buf_chunk;
1027
1028 if (chunk < 1024)
1029 chunk = 1024;
1030
1031 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1032 if (!buf_chunk) {
1033 ret = -ENOMEM;
1034 goto out;
1035 }
1036 kfree(tty->write_buf);
1037 tty->write_cnt = chunk;
1038 tty->write_buf = buf_chunk;
1039 }
1040
1041 /* Do the write .. */
1042 for (;;) {
1043 size_t size = count;
1044 if (size > chunk)
1045 size = chunk;
1046 ret = -EFAULT;
1047 if (copy_from_user(tty->write_buf, buf, size))
1048 break;
1049 ret = write(tty, file, tty->write_buf, size);
1050 if (ret <= 0)
1051 break;
1052 written += ret;
1053 buf += ret;
1054 count -= ret;
1055 if (!count)
1056 break;
1057 ret = -ERESTARTSYS;
1058 if (signal_pending(current))
1059 break;
1060 cond_resched();
1061 }
1062 if (written) {
1063 struct inode *inode = file->f_path.dentry->d_inode;
1064 inode->i_mtime = current_fs_time(inode->i_sb);
1065 ret = written;
1066 }
1067out:
1068 tty_write_unlock(tty);
1069 return ret;
1070}
1071
1072/**
1073 * tty_write_message - write a message to a certain tty, not just the console.
1074 * @tty: the destination tty_struct
1075 * @msg: the message to write
1076 *
1077 * This is used for messages that need to be redirected to a specific tty.
1078 * We don't put it into the syslog queue right now maybe in the future if
1079 * really needed.
1080 *
1081 * We must still hold the BTM and test the CLOSING flag for the moment.
1082 */
1083
1084void tty_write_message(struct tty_struct *tty, char *msg)
1085{
1086 if (tty) {
1087 mutex_lock(&tty->atomic_write_lock);
1088 tty_lock();
1089 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1090 tty_unlock();
1091 tty->ops->write(tty, msg, strlen(msg));
1092 } else
1093 tty_unlock();
1094 tty_write_unlock(tty);
1095 }
1096 return;
1097}
1098
1099
1100/**
1101 * tty_write - write method for tty device file
1102 * @file: tty file pointer
1103 * @buf: user data to write
1104 * @count: bytes to write
1105 * @ppos: unused
1106 *
1107 * Write data to a tty device via the line discipline.
1108 *
1109 * Locking:
1110 * Locks the line discipline as required
1111 * Writes to the tty driver are serialized by the atomic_write_lock
1112 * and are then processed in chunks to the device. The line discipline
1113 * write method will not be invoked in parallel for each device.
1114 */
1115
1116static ssize_t tty_write(struct file *file, const char __user *buf,
1117 size_t count, loff_t *ppos)
1118{
1119 struct inode *inode = file->f_path.dentry->d_inode;
1120 struct tty_struct *tty = file_tty(file);
1121 struct tty_ldisc *ld;
1122 ssize_t ret;
1123
1124 if (tty_paranoia_check(tty, inode, "tty_write"))
1125 return -EIO;
1126 if (!tty || !tty->ops->write ||
1127 (test_bit(TTY_IO_ERROR, &tty->flags)))
1128 return -EIO;
1129 /* Short term debug to catch buggy drivers */
1130 if (tty->ops->write_room == NULL)
1131 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1132 tty->driver->name);
1133 ld = tty_ldisc_ref_wait(tty);
1134 if (!ld->ops->write)
1135 ret = -EIO;
1136 else
1137 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1138 tty_ldisc_deref(ld);
1139 return ret;
1140}
1141
1142ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1143 size_t count, loff_t *ppos)
1144{
1145 struct file *p = NULL;
1146
1147 spin_lock(&redirect_lock);
1148 if (redirect) {
1149 get_file(redirect);
1150 p = redirect;
1151 }
1152 spin_unlock(&redirect_lock);
1153
1154 if (p) {
1155 ssize_t res;
1156 res = vfs_write(p, buf, count, &p->f_pos);
1157 fput(p);
1158 return res;
1159 }
1160 return tty_write(file, buf, count, ppos);
1161}
1162
1163static char ptychar[] = "pqrstuvwxyzabcde";
1164
1165/**
1166 * pty_line_name - generate name for a pty
1167 * @driver: the tty driver in use
1168 * @index: the minor number
1169 * @p: output buffer of at least 6 bytes
1170 *
1171 * Generate a name from a driver reference and write it to the output
1172 * buffer.
1173 *
1174 * Locking: None
1175 */
1176static void pty_line_name(struct tty_driver *driver, int index, char *p)
1177{
1178 int i = index + driver->name_base;
1179 /* ->name is initialized to "ttyp", but "tty" is expected */
1180 sprintf(p, "%s%c%x",
1181 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1182 ptychar[i >> 4 & 0xf], i & 0xf);
1183}
1184
1185/**
1186 * tty_line_name - generate name for a tty
1187 * @driver: the tty driver in use
1188 * @index: the minor number
1189 * @p: output buffer of at least 7 bytes
1190 *
1191 * Generate a name from a driver reference and write it to the output
1192 * buffer.
1193 *
1194 * Locking: None
1195 */
1196static void tty_line_name(struct tty_driver *driver, int index, char *p)
1197{
1198 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1199}
1200
1201/**
1202 * tty_driver_lookup_tty() - find an existing tty, if any
1203 * @driver: the driver for the tty
1204 * @idx: the minor number
1205 *
1206 * Return the tty, if found or ERR_PTR() otherwise.
1207 *
1208 * Locking: tty_mutex must be held. If tty is found, the mutex must
1209 * be held until the 'fast-open' is also done. Will change once we
1210 * have refcounting in the driver and per driver locking
1211 */
1212static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1213 struct inode *inode, int idx)
1214{
1215 struct tty_struct *tty;
1216
1217 if (driver->ops->lookup)
1218 return driver->ops->lookup(driver, inode, idx);
1219
1220 tty = driver->ttys[idx];
1221 return tty;
1222}
1223
1224/**
1225 * tty_init_termios - helper for termios setup
1226 * @tty: the tty to set up
1227 *
1228 * Initialise the termios structures for this tty. Thus runs under
1229 * the tty_mutex currently so we can be relaxed about ordering.
1230 */
1231
1232int tty_init_termios(struct tty_struct *tty)
1233{
1234 struct ktermios *tp;
1235 int idx = tty->index;
1236
1237 tp = tty->driver->termios[idx];
1238 if (tp == NULL) {
1239 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1240 if (tp == NULL)
1241 return -ENOMEM;
1242 memcpy(tp, &tty->driver->init_termios,
1243 sizeof(struct ktermios));
1244 tty->driver->termios[idx] = tp;
1245 }
1246 tty->termios = tp;
1247 tty->termios_locked = tp + 1;
1248
1249 /* Compatibility until drivers always set this */
1250 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1251 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1252 return 0;
1253}
1254EXPORT_SYMBOL_GPL(tty_init_termios);
1255
1256/**
1257 * tty_driver_install_tty() - install a tty entry in the driver
1258 * @driver: the driver for the tty
1259 * @tty: the tty
1260 *
1261 * Install a tty object into the driver tables. The tty->index field
1262 * will be set by the time this is called. This method is responsible
1263 * for ensuring any need additional structures are allocated and
1264 * configured.
1265 *
1266 * Locking: tty_mutex for now
1267 */
1268static int tty_driver_install_tty(struct tty_driver *driver,
1269 struct tty_struct *tty)
1270{
1271 int idx = tty->index;
1272 int ret;
1273
1274 if (driver->ops->install) {
1275 ret = driver->ops->install(driver, tty);
1276 return ret;
1277 }
1278
1279 if (tty_init_termios(tty) == 0) {
1280 tty_driver_kref_get(driver);
1281 tty->count++;
1282 driver->ttys[idx] = tty;
1283 return 0;
1284 }
1285 return -ENOMEM;
1286}
1287
1288/**
1289 * tty_driver_remove_tty() - remove a tty from the driver tables
1290 * @driver: the driver for the tty
1291 * @idx: the minor number
1292 *
1293 * Remvoe a tty object from the driver tables. The tty->index field
1294 * will be set by the time this is called.
1295 *
1296 * Locking: tty_mutex for now
1297 */
1298void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1299{
1300 if (driver->ops->remove)
1301 driver->ops->remove(driver, tty);
1302 else
1303 driver->ttys[tty->index] = NULL;
1304}
1305
1306/*
1307 * tty_reopen() - fast re-open of an open tty
1308 * @tty - the tty to open
1309 *
1310 * Return 0 on success, -errno on error.
1311 *
1312 * Locking: tty_mutex must be held from the time the tty was found
1313 * till this open completes.
1314 */
1315static int tty_reopen(struct tty_struct *tty)
1316{
1317 struct tty_driver *driver = tty->driver;
1318
1319 if (test_bit(TTY_CLOSING, &tty->flags) ||
1320 test_bit(TTY_HUPPING, &tty->flags) ||
1321 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1322 return -EIO;
1323
1324 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1325 driver->subtype == PTY_TYPE_MASTER) {
1326 /*
1327 * special case for PTY masters: only one open permitted,
1328 * and the slave side open count is incremented as well.
1329 */
1330 if (tty->count)
1331 return -EIO;
1332
1333 tty->link->count++;
1334 }
1335 tty->count++;
1336 tty->driver = driver; /* N.B. why do this every time?? */
1337
1338 mutex_lock(&tty->ldisc_mutex);
1339 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1340 mutex_unlock(&tty->ldisc_mutex);
1341
1342 return 0;
1343}
1344
1345/**
1346 * tty_init_dev - initialise a tty device
1347 * @driver: tty driver we are opening a device on
1348 * @idx: device index
1349 * @ret_tty: returned tty structure
1350 * @first_ok: ok to open a new device (used by ptmx)
1351 *
1352 * Prepare a tty device. This may not be a "new" clean device but
1353 * could also be an active device. The pty drivers require special
1354 * handling because of this.
1355 *
1356 * Locking:
1357 * The function is called under the tty_mutex, which
1358 * protects us from the tty struct or driver itself going away.
1359 *
1360 * On exit the tty device has the line discipline attached and
1361 * a reference count of 1. If a pair was created for pty/tty use
1362 * and the other was a pty master then it too has a reference count of 1.
1363 *
1364 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1365 * failed open. The new code protects the open with a mutex, so it's
1366 * really quite straightforward. The mutex locking can probably be
1367 * relaxed for the (most common) case of reopening a tty.
1368 */
1369
1370struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1371 int first_ok)
1372{
1373 struct tty_struct *tty;
1374 int retval;
1375
1376 /* Check if pty master is being opened multiple times */
1377 if (driver->subtype == PTY_TYPE_MASTER &&
1378 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1379 return ERR_PTR(-EIO);
1380 }
1381
1382 /*
1383 * First time open is complex, especially for PTY devices.
1384 * This code guarantees that either everything succeeds and the
1385 * TTY is ready for operation, or else the table slots are vacated
1386 * and the allocated memory released. (Except that the termios
1387 * and locked termios may be retained.)
1388 */
1389
1390 if (!try_module_get(driver->owner))
1391 return ERR_PTR(-ENODEV);
1392
1393 tty = alloc_tty_struct();
1394 if (!tty) {
1395 retval = -ENOMEM;
1396 goto err_module_put;
1397 }
1398 initialize_tty_struct(tty, driver, idx);
1399
1400 retval = tty_driver_install_tty(driver, tty);
1401 if (retval < 0)
1402 goto err_deinit_tty;
1403
1404 /*
1405 * Structures all installed ... call the ldisc open routines.
1406 * If we fail here just call release_tty to clean up. No need
1407 * to decrement the use counts, as release_tty doesn't care.
1408 */
1409 retval = tty_ldisc_setup(tty, tty->link);
1410 if (retval)
1411 goto err_release_tty;
1412 return tty;
1413
1414err_deinit_tty:
1415 deinitialize_tty_struct(tty);
1416 free_tty_struct(tty);
1417err_module_put:
1418 module_put(driver->owner);
1419 return ERR_PTR(retval);
1420
1421 /* call the tty release_tty routine to clean out this slot */
1422err_release_tty:
1423 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1424 "clearing slot %d\n", idx);
1425 release_tty(tty, idx);
1426 return ERR_PTR(retval);
1427}
1428
1429void tty_free_termios(struct tty_struct *tty)
1430{
1431 struct ktermios *tp;
1432 int idx = tty->index;
1433 /* Kill this flag and push into drivers for locking etc */
1434 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1435 /* FIXME: Locking on ->termios array */
1436 tp = tty->termios;
1437 tty->driver->termios[idx] = NULL;
1438 kfree(tp);
1439 }
1440}
1441EXPORT_SYMBOL(tty_free_termios);
1442
1443void tty_shutdown(struct tty_struct *tty)
1444{
1445 tty_driver_remove_tty(tty->driver, tty);
1446 tty_free_termios(tty);
1447}
1448EXPORT_SYMBOL(tty_shutdown);
1449
1450/**
1451 * release_one_tty - release tty structure memory
1452 * @kref: kref of tty we are obliterating
1453 *
1454 * Releases memory associated with a tty structure, and clears out the
1455 * driver table slots. This function is called when a device is no longer
1456 * in use. It also gets called when setup of a device fails.
1457 *
1458 * Locking:
1459 * tty_mutex - sometimes only
1460 * takes the file list lock internally when working on the list
1461 * of ttys that the driver keeps.
1462 *
1463 * This method gets called from a work queue so that the driver private
1464 * cleanup ops can sleep (needed for USB at least)
1465 */
1466static void release_one_tty(struct work_struct *work)
1467{
1468 struct tty_struct *tty =
1469 container_of(work, struct tty_struct, hangup_work);
1470 struct tty_driver *driver = tty->driver;
1471
1472 if (tty->ops->cleanup)
1473 tty->ops->cleanup(tty);
1474
1475 tty->magic = 0;
1476 tty_driver_kref_put(driver);
1477 module_put(driver->owner);
1478
1479 spin_lock(&tty_files_lock);
1480 list_del_init(&tty->tty_files);
1481 spin_unlock(&tty_files_lock);
1482
1483 put_pid(tty->pgrp);
1484 put_pid(tty->session);
1485 free_tty_struct(tty);
1486}
1487
1488static void queue_release_one_tty(struct kref *kref)
1489{
1490 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1491
1492 if (tty->ops->shutdown)
1493 tty->ops->shutdown(tty);
1494 else
1495 tty_shutdown(tty);
1496
1497 /* The hangup queue is now free so we can reuse it rather than
1498 waste a chunk of memory for each port */
1499 INIT_WORK(&tty->hangup_work, release_one_tty);
1500 schedule_work(&tty->hangup_work);
1501}
1502
1503/**
1504 * tty_kref_put - release a tty kref
1505 * @tty: tty device
1506 *
1507 * Release a reference to a tty device and if need be let the kref
1508 * layer destruct the object for us
1509 */
1510
1511void tty_kref_put(struct tty_struct *tty)
1512{
1513 if (tty)
1514 kref_put(&tty->kref, queue_release_one_tty);
1515}
1516EXPORT_SYMBOL(tty_kref_put);
1517
1518/**
1519 * release_tty - release tty structure memory
1520 *
1521 * Release both @tty and a possible linked partner (think pty pair),
1522 * and decrement the refcount of the backing module.
1523 *
1524 * Locking:
1525 * tty_mutex - sometimes only
1526 * takes the file list lock internally when working on the list
1527 * of ttys that the driver keeps.
1528 * FIXME: should we require tty_mutex is held here ??
1529 *
1530 */
1531static void release_tty(struct tty_struct *tty, int idx)
1532{
1533 /* This should always be true but check for the moment */
1534 WARN_ON(tty->index != idx);
1535
1536 if (tty->link)
1537 tty_kref_put(tty->link);
1538 tty_kref_put(tty);
1539}
1540
1541/**
1542 * tty_release - vfs callback for close
1543 * @inode: inode of tty
1544 * @filp: file pointer for handle to tty
1545 *
1546 * Called the last time each file handle is closed that references
1547 * this tty. There may however be several such references.
1548 *
1549 * Locking:
1550 * Takes bkl. See tty_release_dev
1551 *
1552 * Even releasing the tty structures is a tricky business.. We have
1553 * to be very careful that the structures are all released at the
1554 * same time, as interrupts might otherwise get the wrong pointers.
1555 *
1556 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1557 * lead to double frees or releasing memory still in use.
1558 */
1559
1560int tty_release(struct inode *inode, struct file *filp)
1561{
1562 struct tty_struct *tty = file_tty(filp);
1563 struct tty_struct *o_tty;
1564 int pty_master, tty_closing, o_tty_closing, do_sleep;
1565 int devpts;
1566 int idx;
1567 char buf[64];
1568
1569 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1570 return 0;
1571
1572 tty_lock();
1573 check_tty_count(tty, "tty_release_dev");
1574
1575 __tty_fasync(-1, filp, 0);
1576
1577 idx = tty->index;
1578 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1579 tty->driver->subtype == PTY_TYPE_MASTER);
1580 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1581 o_tty = tty->link;
1582
1583#ifdef TTY_PARANOIA_CHECK
1584 if (idx < 0 || idx >= tty->driver->num) {
1585 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1586 "free (%s)\n", tty->name);
1587 tty_unlock();
1588 return 0;
1589 }
1590 if (!devpts) {
1591 if (tty != tty->driver->ttys[idx]) {
1592 tty_unlock();
1593 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1594 "for (%s)\n", idx, tty->name);
1595 return 0;
1596 }
1597 if (tty->termios != tty->driver->termios[idx]) {
1598 tty_unlock();
1599 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1600 "for (%s)\n",
1601 idx, tty->name);
1602 return 0;
1603 }
1604 }
1605#endif
1606
1607#ifdef TTY_DEBUG_HANGUP
1608 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1609 tty_name(tty, buf), tty->count);
1610#endif
1611
1612#ifdef TTY_PARANOIA_CHECK
1613 if (tty->driver->other &&
1614 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1615 if (o_tty != tty->driver->other->ttys[idx]) {
1616 tty_unlock();
1617 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1618 "not o_tty for (%s)\n",
1619 idx, tty->name);
1620 return 0 ;
1621 }
1622 if (o_tty->termios != tty->driver->other->termios[idx]) {
1623 tty_unlock();
1624 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1625 "not o_termios for (%s)\n",
1626 idx, tty->name);
1627 return 0;
1628 }
1629 if (o_tty->link != tty) {
1630 tty_unlock();
1631 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1632 return 0;
1633 }
1634 }
1635#endif
1636 if (tty->ops->close)
1637 tty->ops->close(tty, filp);
1638
1639 tty_unlock();
1640 /*
1641 * Sanity check: if tty->count is going to zero, there shouldn't be
1642 * any waiters on tty->read_wait or tty->write_wait. We test the
1643 * wait queues and kick everyone out _before_ actually starting to
1644 * close. This ensures that we won't block while releasing the tty
1645 * structure.
1646 *
1647 * The test for the o_tty closing is necessary, since the master and
1648 * slave sides may close in any order. If the slave side closes out
1649 * first, its count will be one, since the master side holds an open.
1650 * Thus this test wouldn't be triggered at the time the slave closes,
1651 * so we do it now.
1652 *
1653 * Note that it's possible for the tty to be opened again while we're
1654 * flushing out waiters. By recalculating the closing flags before
1655 * each iteration we avoid any problems.
1656 */
1657 while (1) {
1658 /* Guard against races with tty->count changes elsewhere and
1659 opens on /dev/tty */
1660
1661 mutex_lock(&tty_mutex);
1662 tty_lock();
1663 tty_closing = tty->count <= 1;
1664 o_tty_closing = o_tty &&
1665 (o_tty->count <= (pty_master ? 1 : 0));
1666 do_sleep = 0;
1667
1668 if (tty_closing) {
1669 if (waitqueue_active(&tty->read_wait)) {
1670 wake_up_poll(&tty->read_wait, POLLIN);
1671 do_sleep++;
1672 }
1673 if (waitqueue_active(&tty->write_wait)) {
1674 wake_up_poll(&tty->write_wait, POLLOUT);
1675 do_sleep++;
1676 }
1677 }
1678 if (o_tty_closing) {
1679 if (waitqueue_active(&o_tty->read_wait)) {
1680 wake_up_poll(&o_tty->read_wait, POLLIN);
1681 do_sleep++;
1682 }
1683 if (waitqueue_active(&o_tty->write_wait)) {
1684 wake_up_poll(&o_tty->write_wait, POLLOUT);
1685 do_sleep++;
1686 }
1687 }
1688 if (!do_sleep)
1689 break;
1690
1691 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1692 "active!\n", tty_name(tty, buf));
1693 tty_unlock();
1694 mutex_unlock(&tty_mutex);
1695 schedule();
1696 }
1697
1698 /*
1699 * The closing flags are now consistent with the open counts on
1700 * both sides, and we've completed the last operation that could
1701 * block, so it's safe to proceed with closing.
1702 */
1703 if (pty_master) {
1704 if (--o_tty->count < 0) {
1705 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1706 "(%d) for %s\n",
1707 o_tty->count, tty_name(o_tty, buf));
1708 o_tty->count = 0;
1709 }
1710 }
1711 if (--tty->count < 0) {
1712 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1713 tty->count, tty_name(tty, buf));
1714 tty->count = 0;
1715 }
1716
1717 /*
1718 * We've decremented tty->count, so we need to remove this file
1719 * descriptor off the tty->tty_files list; this serves two
1720 * purposes:
1721 * - check_tty_count sees the correct number of file descriptors
1722 * associated with this tty.
1723 * - do_tty_hangup no longer sees this file descriptor as
1724 * something that needs to be handled for hangups.
1725 */
1726 tty_del_file(filp);
1727
1728 /*
1729 * Perform some housekeeping before deciding whether to return.
1730 *
1731 * Set the TTY_CLOSING flag if this was the last open. In the
1732 * case of a pty we may have to wait around for the other side
1733 * to close, and TTY_CLOSING makes sure we can't be reopened.
1734 */
1735 if (tty_closing)
1736 set_bit(TTY_CLOSING, &tty->flags);
1737 if (o_tty_closing)
1738 set_bit(TTY_CLOSING, &o_tty->flags);
1739
1740 /*
1741 * If _either_ side is closing, make sure there aren't any
1742 * processes that still think tty or o_tty is their controlling
1743 * tty.
1744 */
1745 if (tty_closing || o_tty_closing) {
1746 read_lock(&tasklist_lock);
1747 session_clear_tty(tty->session);
1748 if (o_tty)
1749 session_clear_tty(o_tty->session);
1750 read_unlock(&tasklist_lock);
1751 }
1752
1753 mutex_unlock(&tty_mutex);
1754
1755 /* check whether both sides are closing ... */
1756 if (!tty_closing || (o_tty && !o_tty_closing)) {
1757 tty_unlock();
1758 return 0;
1759 }
1760
1761#ifdef TTY_DEBUG_HANGUP
1762 printk(KERN_DEBUG "freeing tty structure...");
1763#endif
1764 /*
1765 * Ask the line discipline code to release its structures
1766 */
1767 tty_ldisc_release(tty, o_tty);
1768 /*
1769 * The release_tty function takes care of the details of clearing
1770 * the slots and preserving the termios structure.
1771 */
1772 release_tty(tty, idx);
1773
1774 /* Make this pty number available for reallocation */
1775 if (devpts)
1776 devpts_kill_index(inode, idx);
1777 tty_unlock();
1778 return 0;
1779}
1780
1781/**
1782 * tty_open - open a tty device
1783 * @inode: inode of device file
1784 * @filp: file pointer to tty
1785 *
1786 * tty_open and tty_release keep up the tty count that contains the
1787 * number of opens done on a tty. We cannot use the inode-count, as
1788 * different inodes might point to the same tty.
1789 *
1790 * Open-counting is needed for pty masters, as well as for keeping
1791 * track of serial lines: DTR is dropped when the last close happens.
1792 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1793 *
1794 * The termios state of a pty is reset on first open so that
1795 * settings don't persist across reuse.
1796 *
1797 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1798 * tty->count should protect the rest.
1799 * ->siglock protects ->signal/->sighand
1800 */
1801
1802static int tty_open(struct inode *inode, struct file *filp)
1803{
1804 struct tty_struct *tty = NULL;
1805 int noctty, retval;
1806 struct tty_driver *driver;
1807 int index;
1808 dev_t device = inode->i_rdev;
1809 unsigned saved_flags = filp->f_flags;
1810
1811 nonseekable_open(inode, filp);
1812
1813retry_open:
1814 noctty = filp->f_flags & O_NOCTTY;
1815 index = -1;
1816 retval = 0;
1817
1818 mutex_lock(&tty_mutex);
1819 tty_lock();
1820
1821 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1822 tty = get_current_tty();
1823 if (!tty) {
1824 tty_unlock();
1825 mutex_unlock(&tty_mutex);
1826 return -ENXIO;
1827 }
1828 driver = tty_driver_kref_get(tty->driver);
1829 index = tty->index;
1830 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1831 /* noctty = 1; */
1832 /* FIXME: Should we take a driver reference ? */
1833 tty_kref_put(tty);
1834 goto got_driver;
1835 }
1836#ifdef CONFIG_VT
1837 if (device == MKDEV(TTY_MAJOR, 0)) {
1838 extern struct tty_driver *console_driver;
1839 driver = tty_driver_kref_get(console_driver);
1840 index = fg_console;
1841 noctty = 1;
1842 goto got_driver;
1843 }
1844#endif
1845 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1846 struct tty_driver *console_driver = console_device(&index);
1847 if (console_driver) {
1848 driver = tty_driver_kref_get(console_driver);
1849 if (driver) {
1850 /* Don't let /dev/console block */
1851 filp->f_flags |= O_NONBLOCK;
1852 noctty = 1;
1853 goto got_driver;
1854 }
1855 }
1856 tty_unlock();
1857 mutex_unlock(&tty_mutex);
1858 return -ENODEV;
1859 }
1860
1861 driver = get_tty_driver(device, &index);
1862 if (!driver) {
1863 tty_unlock();
1864 mutex_unlock(&tty_mutex);
1865 return -ENODEV;
1866 }
1867got_driver:
1868 if (!tty) {
1869 /* check whether we're reopening an existing tty */
1870 tty = tty_driver_lookup_tty(driver, inode, index);
1871
1872 if (IS_ERR(tty)) {
1873 tty_unlock();
1874 mutex_unlock(&tty_mutex);
1875 return PTR_ERR(tty);
1876 }
1877 }
1878
1879 if (tty) {
1880 retval = tty_reopen(tty);
1881 if (retval)
1882 tty = ERR_PTR(retval);
1883 } else
1884 tty = tty_init_dev(driver, index, 0);
1885
1886 mutex_unlock(&tty_mutex);
1887 tty_driver_kref_put(driver);
1888 if (IS_ERR(tty)) {
1889 tty_unlock();
1890 return PTR_ERR(tty);
1891 }
1892
1893 retval = tty_add_file(tty, filp);
1894 if (retval) {
1895 tty_unlock();
1896 tty_release(inode, filp);
1897 return retval;
1898 }
1899
1900 check_tty_count(tty, "tty_open");
1901 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1902 tty->driver->subtype == PTY_TYPE_MASTER)
1903 noctty = 1;
1904#ifdef TTY_DEBUG_HANGUP
1905 printk(KERN_DEBUG "opening %s...", tty->name);
1906#endif
1907 if (tty->ops->open)
1908 retval = tty->ops->open(tty, filp);
1909 else
1910 retval = -ENODEV;
1911 filp->f_flags = saved_flags;
1912
1913 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1914 !capable(CAP_SYS_ADMIN))
1915 retval = -EBUSY;
1916
1917 if (retval) {
1918#ifdef TTY_DEBUG_HANGUP
1919 printk(KERN_DEBUG "error %d in opening %s...", retval,
1920 tty->name);
1921#endif
1922 tty_unlock(); /* need to call tty_release without BTM */
1923 tty_release(inode, filp);
1924 if (retval != -ERESTARTSYS)
1925 return retval;
1926
1927 if (signal_pending(current))
1928 return retval;
1929
1930 schedule();
1931 /*
1932 * Need to reset f_op in case a hangup happened.
1933 */
1934 tty_lock();
1935 if (filp->f_op == &hung_up_tty_fops)
1936 filp->f_op = &tty_fops;
1937 tty_unlock();
1938 goto retry_open;
1939 }
1940 tty_unlock();
1941
1942
1943 mutex_lock(&tty_mutex);
1944 tty_lock();
1945 spin_lock_irq(¤t->sighand->siglock);
1946 if (!noctty &&
1947 current->signal->leader &&
1948 !current->signal->tty &&
1949 tty->session == NULL)
1950 __proc_set_tty(current, tty);
1951 spin_unlock_irq(¤t->sighand->siglock);
1952 tty_unlock();
1953 mutex_unlock(&tty_mutex);
1954 return 0;
1955}
1956
1957
1958
1959/**
1960 * tty_poll - check tty status
1961 * @filp: file being polled
1962 * @wait: poll wait structures to update
1963 *
1964 * Call the line discipline polling method to obtain the poll
1965 * status of the device.
1966 *
1967 * Locking: locks called line discipline but ldisc poll method
1968 * may be re-entered freely by other callers.
1969 */
1970
1971static unsigned int tty_poll(struct file *filp, poll_table *wait)
1972{
1973 struct tty_struct *tty = file_tty(filp);
1974 struct tty_ldisc *ld;
1975 int ret = 0;
1976
1977 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1978 return 0;
1979
1980 ld = tty_ldisc_ref_wait(tty);
1981 if (ld->ops->poll)
1982 ret = (ld->ops->poll)(tty, filp, wait);
1983 tty_ldisc_deref(ld);
1984 return ret;
1985}
1986
1987static int __tty_fasync(int fd, struct file *filp, int on)
1988{
1989 struct tty_struct *tty = file_tty(filp);
1990 unsigned long flags;
1991 int retval = 0;
1992
1993 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1994 goto out;
1995
1996 retval = fasync_helper(fd, filp, on, &tty->fasync);
1997 if (retval <= 0)
1998 goto out;
1999
2000 if (on) {
2001 enum pid_type type;
2002 struct pid *pid;
2003 if (!waitqueue_active(&tty->read_wait))
2004 tty->minimum_to_wake = 1;
2005 spin_lock_irqsave(&tty->ctrl_lock, flags);
2006 if (tty->pgrp) {
2007 pid = tty->pgrp;
2008 type = PIDTYPE_PGID;
2009 } else {
2010 pid = task_pid(current);
2011 type = PIDTYPE_PID;
2012 }
2013 get_pid(pid);
2014 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2015 retval = __f_setown(filp, pid, type, 0);
2016 put_pid(pid);
2017 if (retval)
2018 goto out;
2019 } else {
2020 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2021 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2022 }
2023 retval = 0;
2024out:
2025 return retval;
2026}
2027
2028static int tty_fasync(int fd, struct file *filp, int on)
2029{
2030 int retval;
2031 tty_lock();
2032 retval = __tty_fasync(fd, filp, on);
2033 tty_unlock();
2034 return retval;
2035}
2036
2037/**
2038 * tiocsti - fake input character
2039 * @tty: tty to fake input into
2040 * @p: pointer to character
2041 *
2042 * Fake input to a tty device. Does the necessary locking and
2043 * input management.
2044 *
2045 * FIXME: does not honour flow control ??
2046 *
2047 * Locking:
2048 * Called functions take tty_ldisc_lock
2049 * current->signal->tty check is safe without locks
2050 *
2051 * FIXME: may race normal receive processing
2052 */
2053
2054static int tiocsti(struct tty_struct *tty, char __user *p)
2055{
2056 char ch, mbz = 0;
2057 struct tty_ldisc *ld;
2058
2059 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2060 return -EPERM;
2061 if (get_user(ch, p))
2062 return -EFAULT;
2063 tty_audit_tiocsti(tty, ch);
2064 ld = tty_ldisc_ref_wait(tty);
2065 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2066 tty_ldisc_deref(ld);
2067 return 0;
2068}
2069
2070/**
2071 * tiocgwinsz - implement window query ioctl
2072 * @tty; tty
2073 * @arg: user buffer for result
2074 *
2075 * Copies the kernel idea of the window size into the user buffer.
2076 *
2077 * Locking: tty->termios_mutex is taken to ensure the winsize data
2078 * is consistent.
2079 */
2080
2081static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2082{
2083 int err;
2084
2085 mutex_lock(&tty->termios_mutex);
2086 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2087 mutex_unlock(&tty->termios_mutex);
2088
2089 return err ? -EFAULT: 0;
2090}
2091
2092/**
2093 * tty_do_resize - resize event
2094 * @tty: tty being resized
2095 * @rows: rows (character)
2096 * @cols: cols (character)
2097 *
2098 * Update the termios variables and send the necessary signals to
2099 * peform a terminal resize correctly
2100 */
2101
2102int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2103{
2104 struct pid *pgrp;
2105 unsigned long flags;
2106
2107 /* Lock the tty */
2108 mutex_lock(&tty->termios_mutex);
2109 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2110 goto done;
2111 /* Get the PID values and reference them so we can
2112 avoid holding the tty ctrl lock while sending signals */
2113 spin_lock_irqsave(&tty->ctrl_lock, flags);
2114 pgrp = get_pid(tty->pgrp);
2115 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2116
2117 if (pgrp)
2118 kill_pgrp(pgrp, SIGWINCH, 1);
2119 put_pid(pgrp);
2120
2121 tty->winsize = *ws;
2122done:
2123 mutex_unlock(&tty->termios_mutex);
2124 return 0;
2125}
2126
2127/**
2128 * tiocswinsz - implement window size set ioctl
2129 * @tty; tty side of tty
2130 * @arg: user buffer for result
2131 *
2132 * Copies the user idea of the window size to the kernel. Traditionally
2133 * this is just advisory information but for the Linux console it
2134 * actually has driver level meaning and triggers a VC resize.
2135 *
2136 * Locking:
2137 * Driver dependent. The default do_resize method takes the
2138 * tty termios mutex and ctrl_lock. The console takes its own lock
2139 * then calls into the default method.
2140 */
2141
2142static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2143{
2144 struct winsize tmp_ws;
2145 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2146 return -EFAULT;
2147
2148 if (tty->ops->resize)
2149 return tty->ops->resize(tty, &tmp_ws);
2150 else
2151 return tty_do_resize(tty, &tmp_ws);
2152}
2153
2154/**
2155 * tioccons - allow admin to move logical console
2156 * @file: the file to become console
2157 *
2158 * Allow the administrator to move the redirected console device
2159 *
2160 * Locking: uses redirect_lock to guard the redirect information
2161 */
2162
2163static int tioccons(struct file *file)
2164{
2165 if (!capable(CAP_SYS_ADMIN))
2166 return -EPERM;
2167 if (file->f_op->write == redirected_tty_write) {
2168 struct file *f;
2169 spin_lock(&redirect_lock);
2170 f = redirect;
2171 redirect = NULL;
2172 spin_unlock(&redirect_lock);
2173 if (f)
2174 fput(f);
2175 return 0;
2176 }
2177 spin_lock(&redirect_lock);
2178 if (redirect) {
2179 spin_unlock(&redirect_lock);
2180 return -EBUSY;
2181 }
2182 get_file(file);
2183 redirect = file;
2184 spin_unlock(&redirect_lock);
2185 return 0;
2186}
2187
2188/**
2189 * fionbio - non blocking ioctl
2190 * @file: file to set blocking value
2191 * @p: user parameter
2192 *
2193 * Historical tty interfaces had a blocking control ioctl before
2194 * the generic functionality existed. This piece of history is preserved
2195 * in the expected tty API of posix OS's.
2196 *
2197 * Locking: none, the open file handle ensures it won't go away.
2198 */
2199
2200static int fionbio(struct file *file, int __user *p)
2201{
2202 int nonblock;
2203
2204 if (get_user(nonblock, p))
2205 return -EFAULT;
2206
2207 spin_lock(&file->f_lock);
2208 if (nonblock)
2209 file->f_flags |= O_NONBLOCK;
2210 else
2211 file->f_flags &= ~O_NONBLOCK;
2212 spin_unlock(&file->f_lock);
2213 return 0;
2214}
2215
2216/**
2217 * tiocsctty - set controlling tty
2218 * @tty: tty structure
2219 * @arg: user argument
2220 *
2221 * This ioctl is used to manage job control. It permits a session
2222 * leader to set this tty as the controlling tty for the session.
2223 *
2224 * Locking:
2225 * Takes tty_mutex() to protect tty instance
2226 * Takes tasklist_lock internally to walk sessions
2227 * Takes ->siglock() when updating signal->tty
2228 */
2229
2230static int tiocsctty(struct tty_struct *tty, int arg)
2231{
2232 int ret = 0;
2233 if (current->signal->leader && (task_session(current) == tty->session))
2234 return ret;
2235
2236 mutex_lock(&tty_mutex);
2237 /*
2238 * The process must be a session leader and
2239 * not have a controlling tty already.
2240 */
2241 if (!current->signal->leader || current->signal->tty) {
2242 ret = -EPERM;
2243 goto unlock;
2244 }
2245
2246 if (tty->session) {
2247 /*
2248 * This tty is already the controlling
2249 * tty for another session group!
2250 */
2251 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2252 /*
2253 * Steal it away
2254 */
2255 read_lock(&tasklist_lock);
2256 session_clear_tty(tty->session);
2257 read_unlock(&tasklist_lock);
2258 } else {
2259 ret = -EPERM;
2260 goto unlock;
2261 }
2262 }
2263 proc_set_tty(current, tty);
2264unlock:
2265 mutex_unlock(&tty_mutex);
2266 return ret;
2267}
2268
2269/**
2270 * tty_get_pgrp - return a ref counted pgrp pid
2271 * @tty: tty to read
2272 *
2273 * Returns a refcounted instance of the pid struct for the process
2274 * group controlling the tty.
2275 */
2276
2277struct pid *tty_get_pgrp(struct tty_struct *tty)
2278{
2279 unsigned long flags;
2280 struct pid *pgrp;
2281
2282 spin_lock_irqsave(&tty->ctrl_lock, flags);
2283 pgrp = get_pid(tty->pgrp);
2284 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2285
2286 return pgrp;
2287}
2288EXPORT_SYMBOL_GPL(tty_get_pgrp);
2289
2290/**
2291 * tiocgpgrp - get process group
2292 * @tty: tty passed by user
2293 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2294 * @p: returned pid
2295 *
2296 * Obtain the process group of the tty. If there is no process group
2297 * return an error.
2298 *
2299 * Locking: none. Reference to current->signal->tty is safe.
2300 */
2301
2302static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2303{
2304 struct pid *pid;
2305 int ret;
2306 /*
2307 * (tty == real_tty) is a cheap way of
2308 * testing if the tty is NOT a master pty.
2309 */
2310 if (tty == real_tty && current->signal->tty != real_tty)
2311 return -ENOTTY;
2312 pid = tty_get_pgrp(real_tty);
2313 ret = put_user(pid_vnr(pid), p);
2314 put_pid(pid);
2315 return ret;
2316}
2317
2318/**
2319 * tiocspgrp - attempt to set process group
2320 * @tty: tty passed by user
2321 * @real_tty: tty side device matching tty passed by user
2322 * @p: pid pointer
2323 *
2324 * Set the process group of the tty to the session passed. Only
2325 * permitted where the tty session is our session.
2326 *
2327 * Locking: RCU, ctrl lock
2328 */
2329
2330static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2331{
2332 struct pid *pgrp;
2333 pid_t pgrp_nr;
2334 int retval = tty_check_change(real_tty);
2335 unsigned long flags;
2336
2337 if (retval == -EIO)
2338 return -ENOTTY;
2339 if (retval)
2340 return retval;
2341 if (!current->signal->tty ||
2342 (current->signal->tty != real_tty) ||
2343 (real_tty->session != task_session(current)))
2344 return -ENOTTY;
2345 if (get_user(pgrp_nr, p))
2346 return -EFAULT;
2347 if (pgrp_nr < 0)
2348 return -EINVAL;
2349 rcu_read_lock();
2350 pgrp = find_vpid(pgrp_nr);
2351 retval = -ESRCH;
2352 if (!pgrp)
2353 goto out_unlock;
2354 retval = -EPERM;
2355 if (session_of_pgrp(pgrp) != task_session(current))
2356 goto out_unlock;
2357 retval = 0;
2358 spin_lock_irqsave(&tty->ctrl_lock, flags);
2359 put_pid(real_tty->pgrp);
2360 real_tty->pgrp = get_pid(pgrp);
2361 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2362out_unlock:
2363 rcu_read_unlock();
2364 return retval;
2365}
2366
2367/**
2368 * tiocgsid - get session id
2369 * @tty: tty passed by user
2370 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2371 * @p: pointer to returned session id
2372 *
2373 * Obtain the session id of the tty. If there is no session
2374 * return an error.
2375 *
2376 * Locking: none. Reference to current->signal->tty is safe.
2377 */
2378
2379static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2380{
2381 /*
2382 * (tty == real_tty) is a cheap way of
2383 * testing if the tty is NOT a master pty.
2384 */
2385 if (tty == real_tty && current->signal->tty != real_tty)
2386 return -ENOTTY;
2387 if (!real_tty->session)
2388 return -ENOTTY;
2389 return put_user(pid_vnr(real_tty->session), p);
2390}
2391
2392/**
2393 * tiocsetd - set line discipline
2394 * @tty: tty device
2395 * @p: pointer to user data
2396 *
2397 * Set the line discipline according to user request.
2398 *
2399 * Locking: see tty_set_ldisc, this function is just a helper
2400 */
2401
2402static int tiocsetd(struct tty_struct *tty, int __user *p)
2403{
2404 int ldisc;
2405 int ret;
2406
2407 if (get_user(ldisc, p))
2408 return -EFAULT;
2409
2410 ret = tty_set_ldisc(tty, ldisc);
2411
2412 return ret;
2413}
2414
2415/**
2416 * send_break - performed time break
2417 * @tty: device to break on
2418 * @duration: timeout in mS
2419 *
2420 * Perform a timed break on hardware that lacks its own driver level
2421 * timed break functionality.
2422 *
2423 * Locking:
2424 * atomic_write_lock serializes
2425 *
2426 */
2427
2428static int send_break(struct tty_struct *tty, unsigned int duration)
2429{
2430 int retval;
2431
2432 if (tty->ops->break_ctl == NULL)
2433 return 0;
2434
2435 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2436 retval = tty->ops->break_ctl(tty, duration);
2437 else {
2438 /* Do the work ourselves */
2439 if (tty_write_lock(tty, 0) < 0)
2440 return -EINTR;
2441 retval = tty->ops->break_ctl(tty, -1);
2442 if (retval)
2443 goto out;
2444 if (!signal_pending(current))
2445 msleep_interruptible(duration);
2446 retval = tty->ops->break_ctl(tty, 0);
2447out:
2448 tty_write_unlock(tty);
2449 if (signal_pending(current))
2450 retval = -EINTR;
2451 }
2452 return retval;
2453}
2454
2455/**
2456 * tty_tiocmget - get modem status
2457 * @tty: tty device
2458 * @file: user file pointer
2459 * @p: pointer to result
2460 *
2461 * Obtain the modem status bits from the tty driver if the feature
2462 * is supported. Return -EINVAL if it is not available.
2463 *
2464 * Locking: none (up to the driver)
2465 */
2466
2467static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2468{
2469 int retval = -EINVAL;
2470
2471 if (tty->ops->tiocmget) {
2472 retval = tty->ops->tiocmget(tty);
2473
2474 if (retval >= 0)
2475 retval = put_user(retval, p);
2476 }
2477 return retval;
2478}
2479
2480/**
2481 * tty_tiocmset - set modem status
2482 * @tty: tty device
2483 * @cmd: command - clear bits, set bits or set all
2484 * @p: pointer to desired bits
2485 *
2486 * Set the modem status bits from the tty driver if the feature
2487 * is supported. Return -EINVAL if it is not available.
2488 *
2489 * Locking: none (up to the driver)
2490 */
2491
2492static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2493 unsigned __user *p)
2494{
2495 int retval;
2496 unsigned int set, clear, val;
2497
2498 if (tty->ops->tiocmset == NULL)
2499 return -EINVAL;
2500
2501 retval = get_user(val, p);
2502 if (retval)
2503 return retval;
2504 set = clear = 0;
2505 switch (cmd) {
2506 case TIOCMBIS:
2507 set = val;
2508 break;
2509 case TIOCMBIC:
2510 clear = val;
2511 break;
2512 case TIOCMSET:
2513 set = val;
2514 clear = ~val;
2515 break;
2516 }
2517 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2518 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2519 return tty->ops->tiocmset(tty, set, clear);
2520}
2521
2522static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2523{
2524 int retval = -EINVAL;
2525 struct serial_icounter_struct icount;
2526 memset(&icount, 0, sizeof(icount));
2527 if (tty->ops->get_icount)
2528 retval = tty->ops->get_icount(tty, &icount);
2529 if (retval != 0)
2530 return retval;
2531 if (copy_to_user(arg, &icount, sizeof(icount)))
2532 return -EFAULT;
2533 return 0;
2534}
2535
2536struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2537{
2538 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2539 tty->driver->subtype == PTY_TYPE_MASTER)
2540 tty = tty->link;
2541 return tty;
2542}
2543EXPORT_SYMBOL(tty_pair_get_tty);
2544
2545struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2546{
2547 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2548 tty->driver->subtype == PTY_TYPE_MASTER)
2549 return tty;
2550 return tty->link;
2551}
2552EXPORT_SYMBOL(tty_pair_get_pty);
2553
2554/*
2555 * Split this up, as gcc can choke on it otherwise..
2556 */
2557long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2558{
2559 struct tty_struct *tty = file_tty(file);
2560 struct tty_struct *real_tty;
2561 void __user *p = (void __user *)arg;
2562 int retval;
2563 struct tty_ldisc *ld;
2564 struct inode *inode = file->f_dentry->d_inode;
2565
2566 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2567 return -EINVAL;
2568
2569 real_tty = tty_pair_get_tty(tty);
2570
2571 /*
2572 * Factor out some common prep work
2573 */
2574 switch (cmd) {
2575 case TIOCSETD:
2576 case TIOCSBRK:
2577 case TIOCCBRK:
2578 case TCSBRK:
2579 case TCSBRKP:
2580 retval = tty_check_change(tty);
2581 if (retval)
2582 return retval;
2583 if (cmd != TIOCCBRK) {
2584 tty_wait_until_sent(tty, 0);
2585 if (signal_pending(current))
2586 return -EINTR;
2587 }
2588 break;
2589 }
2590
2591 /*
2592 * Now do the stuff.
2593 */
2594 switch (cmd) {
2595 case TIOCSTI:
2596 return tiocsti(tty, p);
2597 case TIOCGWINSZ:
2598 return tiocgwinsz(real_tty, p);
2599 case TIOCSWINSZ:
2600 return tiocswinsz(real_tty, p);
2601 case TIOCCONS:
2602 return real_tty != tty ? -EINVAL : tioccons(file);
2603 case FIONBIO:
2604 return fionbio(file, p);
2605 case TIOCEXCL:
2606 set_bit(TTY_EXCLUSIVE, &tty->flags);
2607 return 0;
2608 case TIOCNXCL:
2609 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2610 return 0;
2611 case TIOCNOTTY:
2612 if (current->signal->tty != tty)
2613 return -ENOTTY;
2614 no_tty();
2615 return 0;
2616 case TIOCSCTTY:
2617 return tiocsctty(tty, arg);
2618 case TIOCGPGRP:
2619 return tiocgpgrp(tty, real_tty, p);
2620 case TIOCSPGRP:
2621 return tiocspgrp(tty, real_tty, p);
2622 case TIOCGSID:
2623 return tiocgsid(tty, real_tty, p);
2624 case TIOCGETD:
2625 return put_user(tty->ldisc->ops->num, (int __user *)p);
2626 case TIOCSETD:
2627 return tiocsetd(tty, p);
2628 case TIOCVHANGUP:
2629 if (!capable(CAP_SYS_ADMIN))
2630 return -EPERM;
2631 tty_vhangup(tty);
2632 return 0;
2633 case TIOCGDEV:
2634 {
2635 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2636 return put_user(ret, (unsigned int __user *)p);
2637 }
2638 /*
2639 * Break handling
2640 */
2641 case TIOCSBRK: /* Turn break on, unconditionally */
2642 if (tty->ops->break_ctl)
2643 return tty->ops->break_ctl(tty, -1);
2644 return 0;
2645 case TIOCCBRK: /* Turn break off, unconditionally */
2646 if (tty->ops->break_ctl)
2647 return tty->ops->break_ctl(tty, 0);
2648 return 0;
2649 case TCSBRK: /* SVID version: non-zero arg --> no break */
2650 /* non-zero arg means wait for all output data
2651 * to be sent (performed above) but don't send break.
2652 * This is used by the tcdrain() termios function.
2653 */
2654 if (!arg)
2655 return send_break(tty, 250);
2656 return 0;
2657 case TCSBRKP: /* support for POSIX tcsendbreak() */
2658 return send_break(tty, arg ? arg*100 : 250);
2659
2660 case TIOCMGET:
2661 return tty_tiocmget(tty, p);
2662 case TIOCMSET:
2663 case TIOCMBIC:
2664 case TIOCMBIS:
2665 return tty_tiocmset(tty, cmd, p);
2666 case TIOCGICOUNT:
2667 retval = tty_tiocgicount(tty, p);
2668 /* For the moment allow fall through to the old method */
2669 if (retval != -EINVAL)
2670 return retval;
2671 break;
2672 case TCFLSH:
2673 switch (arg) {
2674 case TCIFLUSH:
2675 case TCIOFLUSH:
2676 /* flush tty buffer and allow ldisc to process ioctl */
2677 tty_buffer_flush(tty);
2678 break;
2679 }
2680 break;
2681 }
2682 if (tty->ops->ioctl) {
2683 retval = (tty->ops->ioctl)(tty, cmd, arg);
2684 if (retval != -ENOIOCTLCMD)
2685 return retval;
2686 }
2687 ld = tty_ldisc_ref_wait(tty);
2688 retval = -EINVAL;
2689 if (ld->ops->ioctl) {
2690 retval = ld->ops->ioctl(tty, file, cmd, arg);
2691 if (retval == -ENOIOCTLCMD)
2692 retval = -EINVAL;
2693 }
2694 tty_ldisc_deref(ld);
2695 return retval;
2696}
2697
2698#ifdef CONFIG_COMPAT
2699static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2700 unsigned long arg)
2701{
2702 struct inode *inode = file->f_dentry->d_inode;
2703 struct tty_struct *tty = file_tty(file);
2704 struct tty_ldisc *ld;
2705 int retval = -ENOIOCTLCMD;
2706
2707 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2708 return -EINVAL;
2709
2710 if (tty->ops->compat_ioctl) {
2711 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2712 if (retval != -ENOIOCTLCMD)
2713 return retval;
2714 }
2715
2716 ld = tty_ldisc_ref_wait(tty);
2717 if (ld->ops->compat_ioctl)
2718 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2719 tty_ldisc_deref(ld);
2720
2721 return retval;
2722}
2723#endif
2724
2725/*
2726 * This implements the "Secure Attention Key" --- the idea is to
2727 * prevent trojan horses by killing all processes associated with this
2728 * tty when the user hits the "Secure Attention Key". Required for
2729 * super-paranoid applications --- see the Orange Book for more details.
2730 *
2731 * This code could be nicer; ideally it should send a HUP, wait a few
2732 * seconds, then send a INT, and then a KILL signal. But you then
2733 * have to coordinate with the init process, since all processes associated
2734 * with the current tty must be dead before the new getty is allowed
2735 * to spawn.
2736 *
2737 * Now, if it would be correct ;-/ The current code has a nasty hole -
2738 * it doesn't catch files in flight. We may send the descriptor to ourselves
2739 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2740 *
2741 * Nasty bug: do_SAK is being called in interrupt context. This can
2742 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2743 */
2744void __do_SAK(struct tty_struct *tty)
2745{
2746#ifdef TTY_SOFT_SAK
2747 tty_hangup(tty);
2748#else
2749 struct task_struct *g, *p;
2750 struct pid *session;
2751 int i;
2752 struct file *filp;
2753 struct fdtable *fdt;
2754
2755 if (!tty)
2756 return;
2757 session = tty->session;
2758
2759 tty_ldisc_flush(tty);
2760
2761 tty_driver_flush_buffer(tty);
2762
2763 read_lock(&tasklist_lock);
2764 /* Kill the entire session */
2765 do_each_pid_task(session, PIDTYPE_SID, p) {
2766 printk(KERN_NOTICE "SAK: killed process %d"
2767 " (%s): task_session(p)==tty->session\n",
2768 task_pid_nr(p), p->comm);
2769 send_sig(SIGKILL, p, 1);
2770 } while_each_pid_task(session, PIDTYPE_SID, p);
2771 /* Now kill any processes that happen to have the
2772 * tty open.
2773 */
2774 do_each_thread(g, p) {
2775 if (p->signal->tty == tty) {
2776 printk(KERN_NOTICE "SAK: killed process %d"
2777 " (%s): task_session(p)==tty->session\n",
2778 task_pid_nr(p), p->comm);
2779 send_sig(SIGKILL, p, 1);
2780 continue;
2781 }
2782 task_lock(p);
2783 if (p->files) {
2784 /*
2785 * We don't take a ref to the file, so we must
2786 * hold ->file_lock instead.
2787 */
2788 spin_lock(&p->files->file_lock);
2789 fdt = files_fdtable(p->files);
2790 for (i = 0; i < fdt->max_fds; i++) {
2791 filp = fcheck_files(p->files, i);
2792 if (!filp)
2793 continue;
2794 if (filp->f_op->read == tty_read &&
2795 file_tty(filp) == tty) {
2796 printk(KERN_NOTICE "SAK: killed process %d"
2797 " (%s): fd#%d opened to the tty\n",
2798 task_pid_nr(p), p->comm, i);
2799 force_sig(SIGKILL, p);
2800 break;
2801 }
2802 }
2803 spin_unlock(&p->files->file_lock);
2804 }
2805 task_unlock(p);
2806 } while_each_thread(g, p);
2807 read_unlock(&tasklist_lock);
2808#endif
2809}
2810
2811static void do_SAK_work(struct work_struct *work)
2812{
2813 struct tty_struct *tty =
2814 container_of(work, struct tty_struct, SAK_work);
2815 __do_SAK(tty);
2816}
2817
2818/*
2819 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2820 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2821 * the values which we write to it will be identical to the values which it
2822 * already has. --akpm
2823 */
2824void do_SAK(struct tty_struct *tty)
2825{
2826 if (!tty)
2827 return;
2828 schedule_work(&tty->SAK_work);
2829}
2830
2831EXPORT_SYMBOL(do_SAK);
2832
2833static int dev_match_devt(struct device *dev, void *data)
2834{
2835 dev_t *devt = data;
2836 return dev->devt == *devt;
2837}
2838
2839/* Must put_device() after it's unused! */
2840static struct device *tty_get_device(struct tty_struct *tty)
2841{
2842 dev_t devt = tty_devnum(tty);
2843 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2844}
2845
2846
2847/**
2848 * initialize_tty_struct
2849 * @tty: tty to initialize
2850 *
2851 * This subroutine initializes a tty structure that has been newly
2852 * allocated.
2853 *
2854 * Locking: none - tty in question must not be exposed at this point
2855 */
2856
2857void initialize_tty_struct(struct tty_struct *tty,
2858 struct tty_driver *driver, int idx)
2859{
2860 memset(tty, 0, sizeof(struct tty_struct));
2861 kref_init(&tty->kref);
2862 tty->magic = TTY_MAGIC;
2863 tty_ldisc_init(tty);
2864 tty->session = NULL;
2865 tty->pgrp = NULL;
2866 tty->overrun_time = jiffies;
2867 tty->buf.head = tty->buf.tail = NULL;
2868 tty_buffer_init(tty);
2869 mutex_init(&tty->termios_mutex);
2870 mutex_init(&tty->ldisc_mutex);
2871 init_waitqueue_head(&tty->write_wait);
2872 init_waitqueue_head(&tty->read_wait);
2873 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2874 mutex_init(&tty->atomic_read_lock);
2875 mutex_init(&tty->atomic_write_lock);
2876 mutex_init(&tty->output_lock);
2877 mutex_init(&tty->echo_lock);
2878 spin_lock_init(&tty->read_lock);
2879 spin_lock_init(&tty->ctrl_lock);
2880 INIT_LIST_HEAD(&tty->tty_files);
2881 INIT_WORK(&tty->SAK_work, do_SAK_work);
2882
2883 tty->driver = driver;
2884 tty->ops = driver->ops;
2885 tty->index = idx;
2886 tty_line_name(driver, idx, tty->name);
2887 tty->dev = tty_get_device(tty);
2888}
2889
2890/**
2891 * deinitialize_tty_struct
2892 * @tty: tty to deinitialize
2893 *
2894 * This subroutine deinitializes a tty structure that has been newly
2895 * allocated but tty_release cannot be called on that yet.
2896 *
2897 * Locking: none - tty in question must not be exposed at this point
2898 */
2899void deinitialize_tty_struct(struct tty_struct *tty)
2900{
2901 tty_ldisc_deinit(tty);
2902}
2903
2904/**
2905 * tty_put_char - write one character to a tty
2906 * @tty: tty
2907 * @ch: character
2908 *
2909 * Write one byte to the tty using the provided put_char method
2910 * if present. Returns the number of characters successfully output.
2911 *
2912 * Note: the specific put_char operation in the driver layer may go
2913 * away soon. Don't call it directly, use this method
2914 */
2915
2916int tty_put_char(struct tty_struct *tty, unsigned char ch)
2917{
2918 if (tty->ops->put_char)
2919 return tty->ops->put_char(tty, ch);
2920 return tty->ops->write(tty, &ch, 1);
2921}
2922EXPORT_SYMBOL_GPL(tty_put_char);
2923
2924struct class *tty_class;
2925
2926/**
2927 * tty_register_device - register a tty device
2928 * @driver: the tty driver that describes the tty device
2929 * @index: the index in the tty driver for this tty device
2930 * @device: a struct device that is associated with this tty device.
2931 * This field is optional, if there is no known struct device
2932 * for this tty device it can be set to NULL safely.
2933 *
2934 * Returns a pointer to the struct device for this tty device
2935 * (or ERR_PTR(-EFOO) on error).
2936 *
2937 * This call is required to be made to register an individual tty device
2938 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2939 * that bit is not set, this function should not be called by a tty
2940 * driver.
2941 *
2942 * Locking: ??
2943 */
2944
2945struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2946 struct device *device)
2947{
2948 char name[64];
2949 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2950
2951 if (index >= driver->num) {
2952 printk(KERN_ERR "Attempt to register invalid tty line number "
2953 " (%d).\n", index);
2954 return ERR_PTR(-EINVAL);
2955 }
2956
2957 if (driver->type == TTY_DRIVER_TYPE_PTY)
2958 pty_line_name(driver, index, name);
2959 else
2960 tty_line_name(driver, index, name);
2961
2962 return device_create(tty_class, device, dev, NULL, name);
2963}
2964EXPORT_SYMBOL(tty_register_device);
2965
2966/**
2967 * tty_unregister_device - unregister a tty device
2968 * @driver: the tty driver that describes the tty device
2969 * @index: the index in the tty driver for this tty device
2970 *
2971 * If a tty device is registered with a call to tty_register_device() then
2972 * this function must be called when the tty device is gone.
2973 *
2974 * Locking: ??
2975 */
2976
2977void tty_unregister_device(struct tty_driver *driver, unsigned index)
2978{
2979 device_destroy(tty_class,
2980 MKDEV(driver->major, driver->minor_start) + index);
2981}
2982EXPORT_SYMBOL(tty_unregister_device);
2983
2984struct tty_driver *alloc_tty_driver(int lines)
2985{
2986 struct tty_driver *driver;
2987
2988 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2989 if (driver) {
2990 kref_init(&driver->kref);
2991 driver->magic = TTY_DRIVER_MAGIC;
2992 driver->num = lines;
2993 /* later we'll move allocation of tables here */
2994 }
2995 return driver;
2996}
2997EXPORT_SYMBOL(alloc_tty_driver);
2998
2999static void destruct_tty_driver(struct kref *kref)
3000{
3001 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3002 int i;
3003 struct ktermios *tp;
3004 void *p;
3005
3006 if (driver->flags & TTY_DRIVER_INSTALLED) {
3007 /*
3008 * Free the termios and termios_locked structures because
3009 * we don't want to get memory leaks when modular tty
3010 * drivers are removed from the kernel.
3011 */
3012 for (i = 0; i < driver->num; i++) {
3013 tp = driver->termios[i];
3014 if (tp) {
3015 driver->termios[i] = NULL;
3016 kfree(tp);
3017 }
3018 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3019 tty_unregister_device(driver, i);
3020 }
3021 p = driver->ttys;
3022 proc_tty_unregister_driver(driver);
3023 driver->ttys = NULL;
3024 driver->termios = NULL;
3025 kfree(p);
3026 cdev_del(&driver->cdev);
3027 }
3028 kfree(driver);
3029}
3030
3031void tty_driver_kref_put(struct tty_driver *driver)
3032{
3033 kref_put(&driver->kref, destruct_tty_driver);
3034}
3035EXPORT_SYMBOL(tty_driver_kref_put);
3036
3037void tty_set_operations(struct tty_driver *driver,
3038 const struct tty_operations *op)
3039{
3040 driver->ops = op;
3041};
3042EXPORT_SYMBOL(tty_set_operations);
3043
3044void put_tty_driver(struct tty_driver *d)
3045{
3046 tty_driver_kref_put(d);
3047}
3048EXPORT_SYMBOL(put_tty_driver);
3049
3050/*
3051 * Called by a tty driver to register itself.
3052 */
3053int tty_register_driver(struct tty_driver *driver)
3054{
3055 int error;
3056 int i;
3057 dev_t dev;
3058 void **p = NULL;
3059 struct device *d;
3060
3061 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3062 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3063 if (!p)
3064 return -ENOMEM;
3065 }
3066
3067 if (!driver->major) {
3068 error = alloc_chrdev_region(&dev, driver->minor_start,
3069 driver->num, driver->name);
3070 if (!error) {
3071 driver->major = MAJOR(dev);
3072 driver->minor_start = MINOR(dev);
3073 }
3074 } else {
3075 dev = MKDEV(driver->major, driver->minor_start);
3076 error = register_chrdev_region(dev, driver->num, driver->name);
3077 }
3078 if (error < 0) {
3079 kfree(p);
3080 return error;
3081 }
3082
3083 if (p) {
3084 driver->ttys = (struct tty_struct **)p;
3085 driver->termios = (struct ktermios **)(p + driver->num);
3086 } else {
3087 driver->ttys = NULL;
3088 driver->termios = NULL;
3089 }
3090
3091 cdev_init(&driver->cdev, &tty_fops);
3092 driver->cdev.owner = driver->owner;
3093 error = cdev_add(&driver->cdev, dev, driver->num);
3094 if (error) {
3095 unregister_chrdev_region(dev, driver->num);
3096 driver->ttys = NULL;
3097 driver->termios = NULL;
3098 kfree(p);
3099 return error;
3100 }
3101
3102 mutex_lock(&tty_mutex);
3103 list_add(&driver->tty_drivers, &tty_drivers);
3104 mutex_unlock(&tty_mutex);
3105
3106 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3107 for (i = 0; i < driver->num; i++) {
3108 d = tty_register_device(driver, i, NULL);
3109 if (IS_ERR(d)) {
3110 error = PTR_ERR(d);
3111 goto err;
3112 }
3113 }
3114 }
3115 proc_tty_register_driver(driver);
3116 driver->flags |= TTY_DRIVER_INSTALLED;
3117 return 0;
3118
3119err:
3120 for (i--; i >= 0; i--)
3121 tty_unregister_device(driver, i);
3122
3123 mutex_lock(&tty_mutex);
3124 list_del(&driver->tty_drivers);
3125 mutex_unlock(&tty_mutex);
3126
3127 unregister_chrdev_region(dev, driver->num);
3128 driver->ttys = NULL;
3129 driver->termios = NULL;
3130 kfree(p);
3131 return error;
3132}
3133
3134EXPORT_SYMBOL(tty_register_driver);
3135
3136/*
3137 * Called by a tty driver to unregister itself.
3138 */
3139int tty_unregister_driver(struct tty_driver *driver)
3140{
3141#if 0
3142 /* FIXME */
3143 if (driver->refcount)
3144 return -EBUSY;
3145#endif
3146 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3147 driver->num);
3148 mutex_lock(&tty_mutex);
3149 list_del(&driver->tty_drivers);
3150 mutex_unlock(&tty_mutex);
3151 return 0;
3152}
3153
3154EXPORT_SYMBOL(tty_unregister_driver);
3155
3156dev_t tty_devnum(struct tty_struct *tty)
3157{
3158 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3159}
3160EXPORT_SYMBOL(tty_devnum);
3161
3162void proc_clear_tty(struct task_struct *p)
3163{
3164 unsigned long flags;
3165 struct tty_struct *tty;
3166 spin_lock_irqsave(&p->sighand->siglock, flags);
3167 tty = p->signal->tty;
3168 p->signal->tty = NULL;
3169 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3170 tty_kref_put(tty);
3171}
3172
3173/* Called under the sighand lock */
3174
3175static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3176{
3177 if (tty) {
3178 unsigned long flags;
3179 /* We should not have a session or pgrp to put here but.... */
3180 spin_lock_irqsave(&tty->ctrl_lock, flags);
3181 put_pid(tty->session);
3182 put_pid(tty->pgrp);
3183 tty->pgrp = get_pid(task_pgrp(tsk));
3184 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3185 tty->session = get_pid(task_session(tsk));
3186 if (tsk->signal->tty) {
3187 printk(KERN_DEBUG "tty not NULL!!\n");
3188 tty_kref_put(tsk->signal->tty);
3189 }
3190 }
3191 put_pid(tsk->signal->tty_old_pgrp);
3192 tsk->signal->tty = tty_kref_get(tty);
3193 tsk->signal->tty_old_pgrp = NULL;
3194}
3195
3196static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3197{
3198 spin_lock_irq(&tsk->sighand->siglock);
3199 __proc_set_tty(tsk, tty);
3200 spin_unlock_irq(&tsk->sighand->siglock);
3201}
3202
3203struct tty_struct *get_current_tty(void)
3204{
3205 struct tty_struct *tty;
3206 unsigned long flags;
3207
3208 spin_lock_irqsave(¤t->sighand->siglock, flags);
3209 tty = tty_kref_get(current->signal->tty);
3210 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3211 return tty;
3212}
3213EXPORT_SYMBOL_GPL(get_current_tty);
3214
3215void tty_default_fops(struct file_operations *fops)
3216{
3217 *fops = tty_fops;
3218}
3219
3220/*
3221 * Initialize the console device. This is called *early*, so
3222 * we can't necessarily depend on lots of kernel help here.
3223 * Just do some early initializations, and do the complex setup
3224 * later.
3225 */
3226void __init console_init(void)
3227{
3228 initcall_t *call;
3229
3230 /* Setup the default TTY line discipline. */
3231 tty_ldisc_begin();
3232
3233 /*
3234 * set up the console device so that later boot sequences can
3235 * inform about problems etc..
3236 */
3237 call = __con_initcall_start;
3238 while (call < __con_initcall_end) {
3239 (*call)();
3240 call++;
3241 }
3242}
3243
3244static char *tty_devnode(struct device *dev, mode_t *mode)
3245{
3246 if (!mode)
3247 return NULL;
3248 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3249 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3250 *mode = 0666;
3251 return NULL;
3252}
3253
3254static int __init tty_class_init(void)
3255{
3256 tty_class = class_create(THIS_MODULE, "tty");
3257 if (IS_ERR(tty_class))
3258 return PTR_ERR(tty_class);
3259 tty_class->devnode = tty_devnode;
3260 return 0;
3261}
3262
3263postcore_initcall(tty_class_init);
3264
3265/* 3/2004 jmc: why do these devices exist? */
3266static struct cdev tty_cdev, console_cdev;
3267
3268static ssize_t show_cons_active(struct device *dev,
3269 struct device_attribute *attr, char *buf)
3270{
3271 struct console *cs[16];
3272 int i = 0;
3273 struct console *c;
3274 ssize_t count = 0;
3275
3276 console_lock();
3277 for_each_console(c) {
3278 if (!c->device)
3279 continue;
3280 if (!c->write)
3281 continue;
3282 if ((c->flags & CON_ENABLED) == 0)
3283 continue;
3284 cs[i++] = c;
3285 if (i >= ARRAY_SIZE(cs))
3286 break;
3287 }
3288 while (i--)
3289 count += sprintf(buf + count, "%s%d%c",
3290 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3291 console_unlock();
3292
3293 return count;
3294}
3295static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3296
3297static struct device *consdev;
3298
3299void console_sysfs_notify(void)
3300{
3301 if (consdev)
3302 sysfs_notify(&consdev->kobj, NULL, "active");
3303}
3304
3305/*
3306 * Ok, now we can initialize the rest of the tty devices and can count
3307 * on memory allocations, interrupts etc..
3308 */
3309int __init tty_init(void)
3310{
3311 cdev_init(&tty_cdev, &tty_fops);
3312 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3313 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3314 panic("Couldn't register /dev/tty driver\n");
3315 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3316
3317 cdev_init(&console_cdev, &console_fops);
3318 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3319 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3320 panic("Couldn't register /dev/console driver\n");
3321 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3322 "console");
3323 if (IS_ERR(consdev))
3324 consdev = NULL;
3325 else
3326 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3327
3328#ifdef CONFIG_VT
3329 vty_init(&console_fops);
3330#endif
3331 return 0;
3332}
3333
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 */
5
6/*
7 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
8 * or rs-channels. It also implements echoing, cooked mode etc.
9 *
10 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 *
12 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
13 * tty_struct and tty_queue structures. Previously there was an array
14 * of 256 tty_struct's which was statically allocated, and the
15 * tty_queue structures were allocated at boot time. Both are now
16 * dynamically allocated only when the tty is open.
17 *
18 * Also restructured routines so that there is more of a separation
19 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
20 * the low-level tty routines (serial.c, pty.c, console.c). This
21 * makes for cleaner and more compact code. -TYT, 9/17/92
22 *
23 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
24 * which can be dynamically activated and de-activated by the line
25 * discipline handling modules (like SLIP).
26 *
27 * NOTE: pay no attention to the line discipline code (yet); its
28 * interface is still subject to change in this version...
29 * -- TYT, 1/31/92
30 *
31 * Added functionality to the OPOST tty handling. No delays, but all
32 * other bits should be there.
33 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 *
35 * Rewrote canonical mode and added more termios flags.
36 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 *
38 * Reorganized FASYNC support so mouse code can share it.
39 * -- ctm@ardi.com, 9Sep95
40 *
41 * New TIOCLINUX variants added.
42 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 *
44 * Restrict vt switching via ioctl()
45 * -- grif@cs.ucr.edu, 5-Dec-95
46 *
47 * Move console and virtual terminal code to more appropriate files,
48 * implement CONFIG_VT and generalize console device interface.
49 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 *
51 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
52 * -- Bill Hawes <whawes@star.net>, June 97
53 *
54 * Added devfs support.
55 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 *
57 * Added support for a Unix98-style ptmx device.
58 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 *
60 * Reduced memory usage for older ARM systems
61 * -- Russell King <rmk@arm.linux.org.uk>
62 *
63 * Move do_SAK() into process context. Less stack use in devfs functions.
64 * alloc_tty_struct() always uses kmalloc()
65 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
66 */
67
68#include <linux/types.h>
69#include <linux/major.h>
70#include <linux/errno.h>
71#include <linux/signal.h>
72#include <linux/fcntl.h>
73#include <linux/sched/signal.h>
74#include <linux/sched/task.h>
75#include <linux/interrupt.h>
76#include <linux/tty.h>
77#include <linux/tty_driver.h>
78#include <linux/tty_flip.h>
79#include <linux/devpts_fs.h>
80#include <linux/file.h>
81#include <linux/fdtable.h>
82#include <linux/console.h>
83#include <linux/timer.h>
84#include <linux/ctype.h>
85#include <linux/kd.h>
86#include <linux/mm.h>
87#include <linux/string.h>
88#include <linux/slab.h>
89#include <linux/poll.h>
90#include <linux/ppp-ioctl.h>
91#include <linux/proc_fs.h>
92#include <linux/init.h>
93#include <linux/module.h>
94#include <linux/device.h>
95#include <linux/wait.h>
96#include <linux/bitops.h>
97#include <linux/delay.h>
98#include <linux/seq_file.h>
99#include <linux/serial.h>
100#include <linux/ratelimit.h>
101#include <linux/compat.h>
102#include <linux/uaccess.h>
103#include <linux/termios_internal.h>
104#include <linux/fs.h>
105
106#include <linux/kbd_kern.h>
107#include <linux/vt_kern.h>
108#include <linux/selection.h>
109
110#include <linux/kmod.h>
111#include <linux/nsproxy.h>
112#include "tty.h"
113
114#undef TTY_DEBUG_HANGUP
115#ifdef TTY_DEBUG_HANGUP
116# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
117#else
118# define tty_debug_hangup(tty, f, args...) do { } while (0)
119#endif
120
121#define TTY_PARANOIA_CHECK 1
122#define CHECK_TTY_COUNT 1
123
124struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
125 .c_iflag = ICRNL | IXON,
126 .c_oflag = OPOST | ONLCR,
127 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
128 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
129 ECHOCTL | ECHOKE | IEXTEN,
130 .c_cc = INIT_C_CC,
131 .c_ispeed = 38400,
132 .c_ospeed = 38400,
133 /* .c_line = N_TTY, */
134};
135EXPORT_SYMBOL(tty_std_termios);
136
137/* This list gets poked at by procfs and various bits of boot up code. This
138 * could do with some rationalisation such as pulling the tty proc function
139 * into this file.
140 */
141
142LIST_HEAD(tty_drivers); /* linked list of tty drivers */
143
144/* Mutex to protect creating and releasing a tty */
145DEFINE_MUTEX(tty_mutex);
146
147static ssize_t tty_read(struct kiocb *, struct iov_iter *);
148static ssize_t tty_write(struct kiocb *, struct iov_iter *);
149static __poll_t tty_poll(struct file *, poll_table *);
150static int tty_open(struct inode *, struct file *);
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 */
169static void free_tty_struct(struct tty_struct *tty)
170{
171 tty_ldisc_deinit(tty);
172 put_device(tty->dev);
173 kvfree(tty->write_buf);
174 kfree(tty);
175}
176
177static inline struct tty_struct *file_tty(struct file *file)
178{
179 return ((struct tty_file_private *)file->private_data)->tty;
180}
181
182int tty_alloc_file(struct file *file)
183{
184 struct tty_file_private *priv;
185
186 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
187 if (!priv)
188 return -ENOMEM;
189
190 file->private_data = priv;
191
192 return 0;
193}
194
195/* Associate a new file with the tty structure */
196void tty_add_file(struct tty_struct *tty, struct file *file)
197{
198 struct tty_file_private *priv = file->private_data;
199
200 priv->tty = tty;
201 priv->file = file;
202
203 spin_lock(&tty->files_lock);
204 list_add(&priv->list, &tty->tty_files);
205 spin_unlock(&tty->files_lock);
206}
207
208/**
209 * tty_free_file - free file->private_data
210 * @file: to free private_data of
211 *
212 * This shall be used only for fail path handling when tty_add_file was not
213 * called yet.
214 */
215void tty_free_file(struct file *file)
216{
217 struct tty_file_private *priv = file->private_data;
218
219 file->private_data = NULL;
220 kfree(priv);
221}
222
223/* Delete file from its tty */
224static void tty_del_file(struct file *file)
225{
226 struct tty_file_private *priv = file->private_data;
227 struct tty_struct *tty = priv->tty;
228
229 spin_lock(&tty->files_lock);
230 list_del(&priv->list);
231 spin_unlock(&tty->files_lock);
232 tty_free_file(file);
233}
234
235/**
236 * tty_name - return tty naming
237 * @tty: tty structure
238 *
239 * Convert a tty structure into a name. The name reflects the kernel naming
240 * policy and if udev is in use may not reflect user space
241 *
242 * Locking: none
243 */
244const char *tty_name(const struct tty_struct *tty)
245{
246 if (!tty) /* Hmm. NULL pointer. That's fun. */
247 return "NULL tty";
248 return tty->name;
249}
250EXPORT_SYMBOL(tty_name);
251
252const char *tty_driver_name(const struct tty_struct *tty)
253{
254 if (!tty || !tty->driver)
255 return "";
256 return tty->driver->name;
257}
258
259static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
260 const char *routine)
261{
262#ifdef TTY_PARANOIA_CHECK
263 if (!tty) {
264 pr_warn("(%d:%d): %s: NULL tty\n",
265 imajor(inode), iminor(inode), routine);
266 return 1;
267 }
268#endif
269 return 0;
270}
271
272/* Caller must hold tty_lock */
273static void check_tty_count(struct tty_struct *tty, const char *routine)
274{
275#ifdef CHECK_TTY_COUNT
276 struct list_head *p;
277 int count = 0, kopen_count = 0;
278
279 spin_lock(&tty->files_lock);
280 list_for_each(p, &tty->tty_files) {
281 count++;
282 }
283 spin_unlock(&tty->files_lock);
284 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
285 tty->driver->subtype == PTY_TYPE_SLAVE &&
286 tty->link && tty->link->count)
287 count++;
288 if (tty_port_kopened(tty->port))
289 kopen_count++;
290 if (tty->count != (count + kopen_count)) {
291 tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n",
292 routine, tty->count, count, kopen_count);
293 }
294#endif
295}
296
297/**
298 * get_tty_driver - find device of a tty
299 * @device: device identifier
300 * @index: returns the index of the tty
301 *
302 * This routine returns a tty driver structure, given a device number and also
303 * passes back the index number.
304 *
305 * Locking: caller must hold tty_mutex
306 */
307static struct tty_driver *get_tty_driver(dev_t device, int *index)
308{
309 struct tty_driver *p;
310
311 list_for_each_entry(p, &tty_drivers, tty_drivers) {
312 dev_t base = MKDEV(p->major, p->minor_start);
313
314 if (device < base || device >= base + p->num)
315 continue;
316 *index = device - base;
317 return tty_driver_kref_get(p);
318 }
319 return NULL;
320}
321
322/**
323 * tty_dev_name_to_number - return dev_t for device name
324 * @name: user space name of device under /dev
325 * @number: pointer to dev_t that this function will populate
326 *
327 * This function converts device names like ttyS0 or ttyUSB1 into dev_t like
328 * (4, 64) or (188, 1). If no corresponding driver is registered then the
329 * function returns -%ENODEV.
330 *
331 * Locking: this acquires tty_mutex to protect the tty_drivers list from
332 * being modified while we are traversing it, and makes sure to
333 * release it before exiting.
334 */
335int tty_dev_name_to_number(const char *name, dev_t *number)
336{
337 struct tty_driver *p;
338 int ret;
339 int index, prefix_length = 0;
340 const char *str;
341
342 for (str = name; *str && !isdigit(*str); str++)
343 ;
344
345 if (!*str)
346 return -EINVAL;
347
348 ret = kstrtoint(str, 10, &index);
349 if (ret)
350 return ret;
351
352 prefix_length = str - name;
353 mutex_lock(&tty_mutex);
354
355 list_for_each_entry(p, &tty_drivers, tty_drivers)
356 if (prefix_length == strlen(p->name) && strncmp(name,
357 p->name, prefix_length) == 0) {
358 if (index < p->num) {
359 *number = MKDEV(p->major, p->minor_start + index);
360 goto out;
361 }
362 }
363
364 /* if here then driver wasn't found */
365 ret = -ENODEV;
366out:
367 mutex_unlock(&tty_mutex);
368 return ret;
369}
370EXPORT_SYMBOL_GPL(tty_dev_name_to_number);
371
372#ifdef CONFIG_CONSOLE_POLL
373
374/**
375 * tty_find_polling_driver - find device of a polled tty
376 * @name: name string to match
377 * @line: pointer to resulting tty line nr
378 *
379 * This routine returns a tty driver structure, given a name and the condition
380 * that the tty driver is capable of polled operation.
381 */
382struct tty_driver *tty_find_polling_driver(char *name, int *line)
383{
384 struct tty_driver *p, *res = NULL;
385 int tty_line = 0;
386 int len;
387 char *str, *stp;
388
389 for (str = name; *str; str++)
390 if ((*str >= '0' && *str <= '9') || *str == ',')
391 break;
392 if (!*str)
393 return NULL;
394
395 len = str - name;
396 tty_line = simple_strtoul(str, &str, 10);
397
398 mutex_lock(&tty_mutex);
399 /* Search through the tty devices to look for a match */
400 list_for_each_entry(p, &tty_drivers, tty_drivers) {
401 if (!len || strncmp(name, p->name, len) != 0)
402 continue;
403 stp = str;
404 if (*stp == ',')
405 stp++;
406 if (*stp == '\0')
407 stp = NULL;
408
409 if (tty_line >= 0 && tty_line < p->num && p->ops &&
410 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
411 res = tty_driver_kref_get(p);
412 *line = tty_line;
413 break;
414 }
415 }
416 mutex_unlock(&tty_mutex);
417
418 return res;
419}
420EXPORT_SYMBOL_GPL(tty_find_polling_driver);
421#endif
422
423static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to)
424{
425 return 0;
426}
427
428static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
429{
430 return -EIO;
431}
432
433/* No kernel lock held - none needed ;) */
434static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait)
435{
436 return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM;
437}
438
439static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
440 unsigned long arg)
441{
442 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
443}
444
445static long hung_up_tty_compat_ioctl(struct file *file,
446 unsigned int cmd, unsigned long arg)
447{
448 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
449}
450
451static int hung_up_tty_fasync(int fd, struct file *file, int on)
452{
453 return -ENOTTY;
454}
455
456static void tty_show_fdinfo(struct seq_file *m, struct file *file)
457{
458 struct tty_struct *tty = file_tty(file);
459
460 if (tty && tty->ops && tty->ops->show_fdinfo)
461 tty->ops->show_fdinfo(tty, m);
462}
463
464static const struct file_operations tty_fops = {
465 .llseek = no_llseek,
466 .read_iter = tty_read,
467 .write_iter = tty_write,
468 .splice_read = copy_splice_read,
469 .splice_write = iter_file_splice_write,
470 .poll = tty_poll,
471 .unlocked_ioctl = tty_ioctl,
472 .compat_ioctl = tty_compat_ioctl,
473 .open = tty_open,
474 .release = tty_release,
475 .fasync = tty_fasync,
476 .show_fdinfo = tty_show_fdinfo,
477};
478
479static const struct file_operations console_fops = {
480 .llseek = no_llseek,
481 .read_iter = tty_read,
482 .write_iter = redirected_tty_write,
483 .splice_read = copy_splice_read,
484 .splice_write = iter_file_splice_write,
485 .poll = tty_poll,
486 .unlocked_ioctl = tty_ioctl,
487 .compat_ioctl = tty_compat_ioctl,
488 .open = tty_open,
489 .release = tty_release,
490 .fasync = tty_fasync,
491};
492
493static const struct file_operations hung_up_tty_fops = {
494 .llseek = no_llseek,
495 .read_iter = hung_up_tty_read,
496 .write_iter = hung_up_tty_write,
497 .poll = hung_up_tty_poll,
498 .unlocked_ioctl = hung_up_tty_ioctl,
499 .compat_ioctl = hung_up_tty_compat_ioctl,
500 .release = tty_release,
501 .fasync = hung_up_tty_fasync,
502};
503
504static DEFINE_SPINLOCK(redirect_lock);
505static struct file *redirect;
506
507/**
508 * tty_wakeup - request more data
509 * @tty: terminal
510 *
511 * Internal and external helper for wakeups of tty. This function informs the
512 * line discipline if present that the driver is ready to receive more output
513 * data.
514 */
515void tty_wakeup(struct tty_struct *tty)
516{
517 struct tty_ldisc *ld;
518
519 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
520 ld = tty_ldisc_ref(tty);
521 if (ld) {
522 if (ld->ops->write_wakeup)
523 ld->ops->write_wakeup(tty);
524 tty_ldisc_deref(ld);
525 }
526 }
527 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
528}
529EXPORT_SYMBOL_GPL(tty_wakeup);
530
531/**
532 * tty_release_redirect - Release a redirect on a pty if present
533 * @tty: tty device
534 *
535 * This is available to the pty code so if the master closes, if the slave is a
536 * redirect it can release the redirect.
537 */
538static struct file *tty_release_redirect(struct tty_struct *tty)
539{
540 struct file *f = NULL;
541
542 spin_lock(&redirect_lock);
543 if (redirect && file_tty(redirect) == tty) {
544 f = redirect;
545 redirect = NULL;
546 }
547 spin_unlock(&redirect_lock);
548
549 return f;
550}
551
552/**
553 * __tty_hangup - actual handler for hangup events
554 * @tty: tty device
555 * @exit_session: if non-zero, signal all foreground group processes
556 *
557 * This can be called by a "kworker" kernel thread. That is process synchronous
558 * but doesn't hold any locks, so we need to make sure we have the appropriate
559 * locks for what we're doing.
560 *
561 * The hangup event clears any pending redirections onto the hung up device. It
562 * ensures future writes will error and it does the needed line discipline
563 * hangup and signal delivery. The tty object itself remains intact.
564 *
565 * Locking:
566 * * BTM
567 *
568 * * redirect lock for undoing redirection
569 * * file list lock for manipulating list of ttys
570 * * tty_ldiscs_lock from called functions
571 * * termios_rwsem resetting termios data
572 * * tasklist_lock to walk task list for hangup event
573 *
574 * * ->siglock to protect ->signal/->sighand
575 *
576 */
577static void __tty_hangup(struct tty_struct *tty, int exit_session)
578{
579 struct file *cons_filp = NULL;
580 struct file *filp, *f;
581 struct tty_file_private *priv;
582 int closecount = 0, n;
583 int refs;
584
585 if (!tty)
586 return;
587
588 f = tty_release_redirect(tty);
589
590 tty_lock(tty);
591
592 if (test_bit(TTY_HUPPED, &tty->flags)) {
593 tty_unlock(tty);
594 return;
595 }
596
597 /*
598 * Some console devices aren't actually hung up for technical and
599 * historical reasons, which can lead to indefinite interruptible
600 * sleep in n_tty_read(). The following explicitly tells
601 * n_tty_read() to abort readers.
602 */
603 set_bit(TTY_HUPPING, &tty->flags);
604
605 /* inuse_filps is protected by the single tty lock,
606 * this really needs to change if we want to flush the
607 * workqueue with the lock held.
608 */
609 check_tty_count(tty, "tty_hangup");
610
611 spin_lock(&tty->files_lock);
612 /* This breaks for file handles being sent over AF_UNIX sockets ? */
613 list_for_each_entry(priv, &tty->tty_files, list) {
614 filp = priv->file;
615 if (filp->f_op->write_iter == redirected_tty_write)
616 cons_filp = filp;
617 if (filp->f_op->write_iter != tty_write)
618 continue;
619 closecount++;
620 __tty_fasync(-1, filp, 0); /* can't block */
621 filp->f_op = &hung_up_tty_fops;
622 }
623 spin_unlock(&tty->files_lock);
624
625 refs = tty_signal_session_leader(tty, exit_session);
626 /* Account for the p->signal references we killed */
627 while (refs--)
628 tty_kref_put(tty);
629
630 tty_ldisc_hangup(tty, cons_filp != NULL);
631
632 spin_lock_irq(&tty->ctrl.lock);
633 clear_bit(TTY_THROTTLED, &tty->flags);
634 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
635 put_pid(tty->ctrl.session);
636 put_pid(tty->ctrl.pgrp);
637 tty->ctrl.session = NULL;
638 tty->ctrl.pgrp = NULL;
639 tty->ctrl.pktstatus = 0;
640 spin_unlock_irq(&tty->ctrl.lock);
641
642 /*
643 * If one of the devices matches a console pointer, we
644 * cannot just call hangup() because that will cause
645 * tty->count and state->count to go out of sync.
646 * So we just call close() the right number of times.
647 */
648 if (cons_filp) {
649 if (tty->ops->close)
650 for (n = 0; n < closecount; n++)
651 tty->ops->close(tty, cons_filp);
652 } else if (tty->ops->hangup)
653 tty->ops->hangup(tty);
654 /*
655 * We don't want to have driver/ldisc interactions beyond the ones
656 * we did here. The driver layer expects no calls after ->hangup()
657 * from the ldisc side, which is now guaranteed.
658 */
659 set_bit(TTY_HUPPED, &tty->flags);
660 clear_bit(TTY_HUPPING, &tty->flags);
661 tty_unlock(tty);
662
663 if (f)
664 fput(f);
665}
666
667static void do_tty_hangup(struct work_struct *work)
668{
669 struct tty_struct *tty =
670 container_of(work, struct tty_struct, hangup_work);
671
672 __tty_hangup(tty, 0);
673}
674
675/**
676 * tty_hangup - trigger a hangup event
677 * @tty: tty to hangup
678 *
679 * A carrier loss (virtual or otherwise) has occurred on @tty. Schedule a
680 * hangup sequence to run after this event.
681 */
682void tty_hangup(struct tty_struct *tty)
683{
684 tty_debug_hangup(tty, "hangup\n");
685 schedule_work(&tty->hangup_work);
686}
687EXPORT_SYMBOL(tty_hangup);
688
689/**
690 * tty_vhangup - process vhangup
691 * @tty: tty to hangup
692 *
693 * The user has asked via system call for the terminal to be hung up. We do
694 * this synchronously so that when the syscall returns the process is complete.
695 * That guarantee is necessary for security reasons.
696 */
697void tty_vhangup(struct tty_struct *tty)
698{
699 tty_debug_hangup(tty, "vhangup\n");
700 __tty_hangup(tty, 0);
701}
702EXPORT_SYMBOL(tty_vhangup);
703
704
705/**
706 * tty_vhangup_self - process vhangup for own ctty
707 *
708 * Perform a vhangup on the current controlling tty
709 */
710void tty_vhangup_self(void)
711{
712 struct tty_struct *tty;
713
714 tty = get_current_tty();
715 if (tty) {
716 tty_vhangup(tty);
717 tty_kref_put(tty);
718 }
719}
720
721/**
722 * tty_vhangup_session - hangup session leader exit
723 * @tty: tty to hangup
724 *
725 * The session leader is exiting and hanging up its controlling terminal.
726 * Every process in the foreground process group is signalled %SIGHUP.
727 *
728 * We do this synchronously so that when the syscall returns the process is
729 * complete. That guarantee is necessary for security reasons.
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 loss
742 */
743int tty_hung_up_p(struct file *filp)
744{
745 return (filp && filp->f_op == &hung_up_tty_fops);
746}
747EXPORT_SYMBOL(tty_hung_up_p);
748
749void __stop_tty(struct tty_struct *tty)
750{
751 if (tty->flow.stopped)
752 return;
753 tty->flow.stopped = true;
754 if (tty->ops->stop)
755 tty->ops->stop(tty);
756}
757
758/**
759 * stop_tty - propagate flow control
760 * @tty: tty to stop
761 *
762 * Perform flow control to the driver. May be called on an already stopped
763 * device and will not re-call the &tty_driver->stop() method.
764 *
765 * This functionality is used by both the line disciplines for halting incoming
766 * flow and by the driver. It may therefore be called from any context, may be
767 * under the tty %atomic_write_lock but not always.
768 *
769 * Locking:
770 * flow.lock
771 */
772void stop_tty(struct tty_struct *tty)
773{
774 unsigned long flags;
775
776 spin_lock_irqsave(&tty->flow.lock, flags);
777 __stop_tty(tty);
778 spin_unlock_irqrestore(&tty->flow.lock, flags);
779}
780EXPORT_SYMBOL(stop_tty);
781
782void __start_tty(struct tty_struct *tty)
783{
784 if (!tty->flow.stopped || tty->flow.tco_stopped)
785 return;
786 tty->flow.stopped = false;
787 if (tty->ops->start)
788 tty->ops->start(tty);
789 tty_wakeup(tty);
790}
791
792/**
793 * start_tty - propagate flow control
794 * @tty: tty to start
795 *
796 * Start a tty that has been stopped if at all possible. If @tty was previously
797 * stopped and is now being started, the &tty_driver->start() method is invoked
798 * and the line discipline woken.
799 *
800 * Locking:
801 * flow.lock
802 */
803void start_tty(struct tty_struct *tty)
804{
805 unsigned long flags;
806
807 spin_lock_irqsave(&tty->flow.lock, flags);
808 __start_tty(tty);
809 spin_unlock_irqrestore(&tty->flow.lock, flags);
810}
811EXPORT_SYMBOL(start_tty);
812
813static void tty_update_time(struct tty_struct *tty, bool mtime)
814{
815 time64_t sec = ktime_get_real_seconds();
816 struct tty_file_private *priv;
817
818 spin_lock(&tty->files_lock);
819 list_for_each_entry(priv, &tty->tty_files, list) {
820 struct inode *inode = file_inode(priv->file);
821 struct timespec64 time = mtime ? inode_get_mtime(inode) : inode_get_atime(inode);
822
823 /*
824 * We only care if the two values differ in anything other than the
825 * lower three bits (i.e every 8 seconds). If so, then we can update
826 * the time of the tty device, otherwise it could be construded as a
827 * security leak to let userspace know the exact timing of the tty.
828 */
829 if ((sec ^ time.tv_sec) & ~7) {
830 if (mtime)
831 inode_set_mtime(inode, sec, 0);
832 else
833 inode_set_atime(inode, sec, 0);
834 }
835 }
836 spin_unlock(&tty->files_lock);
837}
838
839/*
840 * Iterate on the ldisc ->read() function until we've gotten all
841 * the data the ldisc has for us.
842 *
843 * The "cookie" is something that the ldisc read function can fill
844 * in to let us know that there is more data to be had.
845 *
846 * We promise to continue to call the ldisc until it stops returning
847 * data or clears the cookie. The cookie may be something that the
848 * ldisc maintains state for and needs to free.
849 */
850static ssize_t iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
851 struct file *file, struct iov_iter *to)
852{
853 void *cookie = NULL;
854 unsigned long offset = 0;
855 ssize_t retval = 0;
856 size_t copied, count = iov_iter_count(to);
857 u8 kernel_buf[64];
858
859 do {
860 ssize_t size = min(count, sizeof(kernel_buf));
861
862 size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
863 if (!size)
864 break;
865
866 if (size < 0) {
867 /* Did we have an earlier error (ie -EFAULT)? */
868 if (retval)
869 break;
870 retval = size;
871
872 /*
873 * -EOVERFLOW means we didn't have enough space
874 * for a whole packet, and we shouldn't return
875 * a partial result.
876 */
877 if (retval == -EOVERFLOW)
878 offset = 0;
879 break;
880 }
881
882 copied = copy_to_iter(kernel_buf, size, to);
883 offset += copied;
884 count -= copied;
885
886 /*
887 * If the user copy failed, we still need to do another ->read()
888 * call if we had a cookie to let the ldisc clear up.
889 *
890 * But make sure size is zeroed.
891 */
892 if (unlikely(copied != size)) {
893 count = 0;
894 retval = -EFAULT;
895 }
896 } while (cookie);
897
898 /* We always clear tty buffer in case they contained passwords */
899 memzero_explicit(kernel_buf, sizeof(kernel_buf));
900 return offset ? offset : retval;
901}
902
903
904/**
905 * tty_read - read method for tty device files
906 * @iocb: kernel I/O control block
907 * @to: destination for the data read
908 *
909 * Perform the read system call function on this terminal device. Checks
910 * for hung up devices before calling the line discipline method.
911 *
912 * Locking:
913 * Locks the line discipline internally while needed. Multiple read calls
914 * may be outstanding in parallel.
915 */
916static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
917{
918 struct file *file = iocb->ki_filp;
919 struct inode *inode = file_inode(file);
920 struct tty_struct *tty = file_tty(file);
921 struct tty_ldisc *ld;
922 ssize_t ret;
923
924 if (tty_paranoia_check(tty, inode, "tty_read"))
925 return -EIO;
926 if (!tty || tty_io_error(tty))
927 return -EIO;
928
929 /* We want to wait for the line discipline to sort out in this
930 * situation.
931 */
932 ld = tty_ldisc_ref_wait(tty);
933 if (!ld)
934 return hung_up_tty_read(iocb, to);
935 ret = -EIO;
936 if (ld->ops->read)
937 ret = iterate_tty_read(ld, tty, file, to);
938 tty_ldisc_deref(ld);
939
940 if (ret > 0)
941 tty_update_time(tty, false);
942
943 return ret;
944}
945
946void tty_write_unlock(struct tty_struct *tty)
947{
948 mutex_unlock(&tty->atomic_write_lock);
949 wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);
950}
951
952int tty_write_lock(struct tty_struct *tty, bool ndelay)
953{
954 if (!mutex_trylock(&tty->atomic_write_lock)) {
955 if (ndelay)
956 return -EAGAIN;
957 if (mutex_lock_interruptible(&tty->atomic_write_lock))
958 return -ERESTARTSYS;
959 }
960 return 0;
961}
962
963/*
964 * Split writes up in sane blocksizes to avoid
965 * denial-of-service type attacks
966 */
967static ssize_t iterate_tty_write(struct tty_ldisc *ld, struct tty_struct *tty,
968 struct file *file, struct iov_iter *from)
969{
970 size_t chunk, count = iov_iter_count(from);
971 ssize_t ret, written = 0;
972
973 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
974 if (ret < 0)
975 return ret;
976
977 /*
978 * We chunk up writes into a temporary buffer. This
979 * simplifies low-level drivers immensely, since they
980 * don't have locking issues and user mode accesses.
981 *
982 * But if TTY_NO_WRITE_SPLIT is set, we should use a
983 * big chunk-size..
984 *
985 * The default chunk-size is 2kB, because the NTTY
986 * layer has problems with bigger chunks. It will
987 * claim to be able to handle more characters than
988 * it actually does.
989 */
990 chunk = 2048;
991 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
992 chunk = 65536;
993 if (count < chunk)
994 chunk = count;
995
996 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
997 if (tty->write_cnt < chunk) {
998 u8 *buf_chunk;
999
1000 if (chunk < 1024)
1001 chunk = 1024;
1002
1003 buf_chunk = kvmalloc(chunk, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1004 if (!buf_chunk) {
1005 ret = -ENOMEM;
1006 goto out;
1007 }
1008 kvfree(tty->write_buf);
1009 tty->write_cnt = chunk;
1010 tty->write_buf = buf_chunk;
1011 }
1012
1013 /* Do the write .. */
1014 for (;;) {
1015 size_t size = min(chunk, count);
1016
1017 ret = -EFAULT;
1018 if (copy_from_iter(tty->write_buf, size, from) != size)
1019 break;
1020
1021 ret = ld->ops->write(tty, file, tty->write_buf, size);
1022 if (ret <= 0)
1023 break;
1024
1025 written += ret;
1026 if (ret > size)
1027 break;
1028
1029 /* FIXME! Have Al check this! */
1030 if (ret != size)
1031 iov_iter_revert(from, size-ret);
1032
1033 count -= ret;
1034 if (!count)
1035 break;
1036 ret = -ERESTARTSYS;
1037 if (signal_pending(current))
1038 break;
1039 cond_resched();
1040 }
1041 if (written) {
1042 tty_update_time(tty, true);
1043 ret = written;
1044 }
1045out:
1046 tty_write_unlock(tty);
1047 return ret;
1048}
1049
1050#ifdef CONFIG_PRINT_QUOTA_WARNING
1051/**
1052 * tty_write_message - write a message to a certain tty, not just the console.
1053 * @tty: the destination tty_struct
1054 * @msg: the message to write
1055 *
1056 * This is used for messages that need to be redirected to a specific tty. We
1057 * don't put it into the syslog queue right now maybe in the future if really
1058 * needed.
1059 *
1060 * We must still hold the BTM and test the CLOSING flag for the moment.
1061 *
1062 * This function is DEPRECATED, do not use in new code.
1063 */
1064void tty_write_message(struct tty_struct *tty, char *msg)
1065{
1066 if (tty) {
1067 mutex_lock(&tty->atomic_write_lock);
1068 tty_lock(tty);
1069 if (tty->ops->write && tty->count > 0)
1070 tty->ops->write(tty, msg, strlen(msg));
1071 tty_unlock(tty);
1072 tty_write_unlock(tty);
1073 }
1074}
1075#endif
1076
1077static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_iter *from)
1078{
1079 struct tty_struct *tty = file_tty(file);
1080 struct tty_ldisc *ld;
1081 ssize_t ret;
1082
1083 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1084 return -EIO;
1085 if (!tty || !tty->ops->write || tty_io_error(tty))
1086 return -EIO;
1087 /* Short term debug to catch buggy drivers */
1088 if (tty->ops->write_room == NULL)
1089 tty_err(tty, "missing write_room method\n");
1090 ld = tty_ldisc_ref_wait(tty);
1091 if (!ld)
1092 return hung_up_tty_write(iocb, from);
1093 if (!ld->ops->write)
1094 ret = -EIO;
1095 else
1096 ret = iterate_tty_write(ld, tty, file, from);
1097 tty_ldisc_deref(ld);
1098 return ret;
1099}
1100
1101/**
1102 * tty_write - write method for tty device file
1103 * @iocb: kernel I/O control block
1104 * @from: iov_iter with data to write
1105 *
1106 * Write data to a tty device via the line discipline.
1107 *
1108 * Locking:
1109 * Locks the line discipline as required
1110 * Writes to the tty driver are serialized by the atomic_write_lock
1111 * and are then processed in chunks to the device. The line
1112 * discipline write method will not be invoked in parallel for
1113 * each device.
1114 */
1115static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from)
1116{
1117 return file_tty_write(iocb->ki_filp, iocb, from);
1118}
1119
1120ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter)
1121{
1122 struct file *p = NULL;
1123
1124 spin_lock(&redirect_lock);
1125 if (redirect)
1126 p = get_file(redirect);
1127 spin_unlock(&redirect_lock);
1128
1129 /*
1130 * We know the redirected tty is just another tty, we can
1131 * call file_tty_write() directly with that file pointer.
1132 */
1133 if (p) {
1134 ssize_t res;
1135
1136 res = file_tty_write(p, iocb, iter);
1137 fput(p);
1138 return res;
1139 }
1140 return tty_write(iocb, iter);
1141}
1142
1143/**
1144 * tty_send_xchar - send priority character
1145 * @tty: the tty to send to
1146 * @ch: xchar to send
1147 *
1148 * Send a high priority character to the tty even if stopped.
1149 *
1150 * Locking: none for xchar method, write ordering for write method.
1151 */
1152int tty_send_xchar(struct tty_struct *tty, u8 ch)
1153{
1154 bool was_stopped = tty->flow.stopped;
1155
1156 if (tty->ops->send_xchar) {
1157 down_read(&tty->termios_rwsem);
1158 tty->ops->send_xchar(tty, ch);
1159 up_read(&tty->termios_rwsem);
1160 return 0;
1161 }
1162
1163 if (tty_write_lock(tty, false) < 0)
1164 return -ERESTARTSYS;
1165
1166 down_read(&tty->termios_rwsem);
1167 if (was_stopped)
1168 start_tty(tty);
1169 tty->ops->write(tty, &ch, 1);
1170 if (was_stopped)
1171 stop_tty(tty);
1172 up_read(&tty->termios_rwsem);
1173 tty_write_unlock(tty);
1174 return 0;
1175}
1176
1177/**
1178 * pty_line_name - generate name for a pty
1179 * @driver: the tty driver in use
1180 * @index: the minor number
1181 * @p: output buffer of at least 6 bytes
1182 *
1183 * Generate a name from a @driver reference and write it to the output buffer
1184 * @p.
1185 *
1186 * Locking: None
1187 */
1188static void pty_line_name(struct tty_driver *driver, int index, char *p)
1189{
1190 static const char ptychar[] = "pqrstuvwxyzabcde";
1191 int i = index + driver->name_base;
1192 /* ->name is initialized to "ttyp", but "tty" is expected */
1193 sprintf(p, "%s%c%x",
1194 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1195 ptychar[i >> 4 & 0xf], i & 0xf);
1196}
1197
1198/**
1199 * tty_line_name - generate name for a tty
1200 * @driver: the tty driver in use
1201 * @index: the minor number
1202 * @p: output buffer of at least 7 bytes
1203 *
1204 * Generate a name from a @driver reference and write it to the output buffer
1205 * @p.
1206 *
1207 * Locking: None
1208 */
1209static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p)
1210{
1211 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1212 return sprintf(p, "%s", driver->name);
1213 else
1214 return sprintf(p, "%s%d", driver->name,
1215 index + driver->name_base);
1216}
1217
1218/**
1219 * tty_driver_lookup_tty() - find an existing tty, if any
1220 * @driver: the driver for the tty
1221 * @file: file object
1222 * @idx: the minor number
1223 *
1224 * Return: the tty, if found. If not found, return %NULL or ERR_PTR() if the
1225 * driver lookup() method returns an error.
1226 *
1227 * Locking: tty_mutex must be held. If the tty is found, bump the tty kref.
1228 */
1229static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1230 struct file *file, int idx)
1231{
1232 struct tty_struct *tty;
1233
1234 if (driver->ops->lookup) {
1235 if (!file)
1236 tty = ERR_PTR(-EIO);
1237 else
1238 tty = driver->ops->lookup(driver, file, idx);
1239 } else {
1240 if (idx >= driver->num)
1241 return ERR_PTR(-EINVAL);
1242 tty = driver->ttys[idx];
1243 }
1244 if (!IS_ERR(tty))
1245 tty_kref_get(tty);
1246 return tty;
1247}
1248
1249/**
1250 * tty_init_termios - helper for termios setup
1251 * @tty: the tty to set up
1252 *
1253 * Initialise the termios structure for this tty. This runs under the
1254 * %tty_mutex currently so we can be relaxed about ordering.
1255 */
1256void tty_init_termios(struct tty_struct *tty)
1257{
1258 struct ktermios *tp;
1259 int idx = tty->index;
1260
1261 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1262 tty->termios = tty->driver->init_termios;
1263 else {
1264 /* Check for lazy saved data */
1265 tp = tty->driver->termios[idx];
1266 if (tp != NULL) {
1267 tty->termios = *tp;
1268 tty->termios.c_line = tty->driver->init_termios.c_line;
1269 } else
1270 tty->termios = tty->driver->init_termios;
1271 }
1272 /* Compatibility until drivers always set this */
1273 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1274 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1275}
1276EXPORT_SYMBOL_GPL(tty_init_termios);
1277
1278/**
1279 * tty_standard_install - usual tty->ops->install
1280 * @driver: the driver for the tty
1281 * @tty: the tty
1282 *
1283 * If the @driver overrides @tty->ops->install, it still can call this function
1284 * to perform the standard install operations.
1285 */
1286int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1287{
1288 tty_init_termios(tty);
1289 tty_driver_kref_get(driver);
1290 tty->count++;
1291 driver->ttys[tty->index] = tty;
1292 return 0;
1293}
1294EXPORT_SYMBOL_GPL(tty_standard_install);
1295
1296/**
1297 * tty_driver_install_tty() - install a tty entry in the driver
1298 * @driver: the driver for the tty
1299 * @tty: the tty
1300 *
1301 * Install a tty object into the driver tables. The @tty->index field will be
1302 * set by the time this is called. This method is responsible for ensuring any
1303 * need additional structures are allocated and configured.
1304 *
1305 * Locking: tty_mutex for now
1306 */
1307static int tty_driver_install_tty(struct tty_driver *driver,
1308 struct tty_struct *tty)
1309{
1310 return driver->ops->install ? driver->ops->install(driver, tty) :
1311 tty_standard_install(driver, tty);
1312}
1313
1314/**
1315 * tty_driver_remove_tty() - remove a tty from the driver tables
1316 * @driver: the driver for the tty
1317 * @tty: tty to remove
1318 *
1319 * Remove a tty object from the driver tables. The tty->index field will be set
1320 * by the time this is called.
1321 *
1322 * Locking: tty_mutex for now
1323 */
1324static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1325{
1326 if (driver->ops->remove)
1327 driver->ops->remove(driver, tty);
1328 else
1329 driver->ttys[tty->index] = NULL;
1330}
1331
1332/**
1333 * tty_reopen() - fast re-open of an open tty
1334 * @tty: the tty to open
1335 *
1336 * Re-opens on master ptys are not allowed and return -%EIO.
1337 *
1338 * Locking: Caller must hold tty_lock
1339 * Return: 0 on success, -errno on error.
1340 */
1341static int tty_reopen(struct tty_struct *tty)
1342{
1343 struct tty_driver *driver = tty->driver;
1344 struct tty_ldisc *ld;
1345 int retval = 0;
1346
1347 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1348 driver->subtype == PTY_TYPE_MASTER)
1349 return -EIO;
1350
1351 if (!tty->count)
1352 return -EAGAIN;
1353
1354 if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
1355 return -EBUSY;
1356
1357 ld = tty_ldisc_ref_wait(tty);
1358 if (ld) {
1359 tty_ldisc_deref(ld);
1360 } else {
1361 retval = tty_ldisc_lock(tty, 5 * HZ);
1362 if (retval)
1363 return retval;
1364
1365 if (!tty->ldisc)
1366 retval = tty_ldisc_reinit(tty, tty->termios.c_line);
1367 tty_ldisc_unlock(tty);
1368 }
1369
1370 if (retval == 0)
1371 tty->count++;
1372
1373 return retval;
1374}
1375
1376/**
1377 * tty_init_dev - initialise a tty device
1378 * @driver: tty driver we are opening a device on
1379 * @idx: device index
1380 *
1381 * Prepare a tty device. This may not be a "new" clean device but could also be
1382 * an active device. The pty drivers require special handling because of this.
1383 *
1384 * Locking:
1385 * The function is called under the tty_mutex, which protects us from the
1386 * tty struct or driver itself going away.
1387 *
1388 * On exit the tty device has the line discipline attached and a reference
1389 * count of 1. If a pair was created for pty/tty use and the other was a pty
1390 * master then it too has a reference count of 1.
1391 *
1392 * WSH 06/09/97: Rewritten to remove races and properly clean up after a failed
1393 * open. The new code protects the open with a mutex, so it's really quite
1394 * straightforward. The mutex locking can probably be relaxed for the (most
1395 * common) case of reopening a tty.
1396 *
1397 * Return: new tty structure
1398 */
1399struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1400{
1401 struct tty_struct *tty;
1402 int retval;
1403
1404 /*
1405 * First time open is complex, especially for PTY devices.
1406 * This code guarantees that either everything succeeds and the
1407 * TTY is ready for operation, or else the table slots are vacated
1408 * and the allocated memory released. (Except that the termios
1409 * may be retained.)
1410 */
1411
1412 if (!try_module_get(driver->owner))
1413 return ERR_PTR(-ENODEV);
1414
1415 tty = alloc_tty_struct(driver, idx);
1416 if (!tty) {
1417 retval = -ENOMEM;
1418 goto err_module_put;
1419 }
1420
1421 tty_lock(tty);
1422 retval = tty_driver_install_tty(driver, tty);
1423 if (retval < 0)
1424 goto err_free_tty;
1425
1426 if (!tty->port)
1427 tty->port = driver->ports[idx];
1428
1429 if (WARN_RATELIMIT(!tty->port,
1430 "%s: %s driver does not set tty->port. This would crash the kernel. Fix the driver!\n",
1431 __func__, tty->driver->name)) {
1432 retval = -EINVAL;
1433 goto err_release_lock;
1434 }
1435
1436 retval = tty_ldisc_lock(tty, 5 * HZ);
1437 if (retval)
1438 goto err_release_lock;
1439 tty->port->itty = tty;
1440
1441 /*
1442 * Structures all installed ... call the ldisc open routines.
1443 * If we fail here just call release_tty to clean up. No need
1444 * to decrement the use counts, as release_tty doesn't care.
1445 */
1446 retval = tty_ldisc_setup(tty, tty->link);
1447 if (retval)
1448 goto err_release_tty;
1449 tty_ldisc_unlock(tty);
1450 /* Return the tty locked so that it cannot vanish under the caller */
1451 return tty;
1452
1453err_free_tty:
1454 tty_unlock(tty);
1455 free_tty_struct(tty);
1456err_module_put:
1457 module_put(driver->owner);
1458 return ERR_PTR(retval);
1459
1460 /* call the tty release_tty routine to clean out this slot */
1461err_release_tty:
1462 tty_ldisc_unlock(tty);
1463 tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n",
1464 retval, idx);
1465err_release_lock:
1466 tty_unlock(tty);
1467 release_tty(tty, idx);
1468 return ERR_PTR(retval);
1469}
1470
1471/**
1472 * tty_save_termios() - save tty termios data in driver table
1473 * @tty: tty whose termios data to save
1474 *
1475 * Locking: Caller guarantees serialisation with tty_init_termios().
1476 */
1477void tty_save_termios(struct tty_struct *tty)
1478{
1479 struct ktermios *tp;
1480 int idx = tty->index;
1481
1482 /* If the port is going to reset then it has no termios to save */
1483 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1484 return;
1485
1486 /* Stash the termios data */
1487 tp = tty->driver->termios[idx];
1488 if (tp == NULL) {
1489 tp = kmalloc(sizeof(*tp), GFP_KERNEL);
1490 if (tp == NULL)
1491 return;
1492 tty->driver->termios[idx] = tp;
1493 }
1494 *tp = tty->termios;
1495}
1496EXPORT_SYMBOL_GPL(tty_save_termios);
1497
1498/**
1499 * tty_flush_works - flush all works of a tty/pty pair
1500 * @tty: tty device to flush works for (or either end of a pty pair)
1501 *
1502 * Sync flush all works belonging to @tty (and the 'other' tty).
1503 */
1504static void tty_flush_works(struct tty_struct *tty)
1505{
1506 flush_work(&tty->SAK_work);
1507 flush_work(&tty->hangup_work);
1508 if (tty->link) {
1509 flush_work(&tty->link->SAK_work);
1510 flush_work(&tty->link->hangup_work);
1511 }
1512}
1513
1514/**
1515 * release_one_tty - release tty structure memory
1516 * @work: work of tty we are obliterating
1517 *
1518 * Releases memory associated with a tty structure, and clears out the
1519 * driver table slots. This function is called when a device is no longer
1520 * in use. It also gets called when setup of a device fails.
1521 *
1522 * Locking:
1523 * takes the file list lock internally when working on the list of ttys
1524 * that the driver keeps.
1525 *
1526 * This method gets called from a work queue so that the driver private
1527 * cleanup ops can sleep (needed for USB at least)
1528 */
1529static void release_one_tty(struct work_struct *work)
1530{
1531 struct tty_struct *tty =
1532 container_of(work, struct tty_struct, hangup_work);
1533 struct tty_driver *driver = tty->driver;
1534 struct module *owner = driver->owner;
1535
1536 if (tty->ops->cleanup)
1537 tty->ops->cleanup(tty);
1538
1539 tty_driver_kref_put(driver);
1540 module_put(owner);
1541
1542 spin_lock(&tty->files_lock);
1543 list_del_init(&tty->tty_files);
1544 spin_unlock(&tty->files_lock);
1545
1546 put_pid(tty->ctrl.pgrp);
1547 put_pid(tty->ctrl.session);
1548 free_tty_struct(tty);
1549}
1550
1551static void queue_release_one_tty(struct kref *kref)
1552{
1553 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1554
1555 /* The hangup queue is now free so we can reuse it rather than
1556 * waste a chunk of memory for each port.
1557 */
1558 INIT_WORK(&tty->hangup_work, release_one_tty);
1559 schedule_work(&tty->hangup_work);
1560}
1561
1562/**
1563 * tty_kref_put - release a tty kref
1564 * @tty: tty device
1565 *
1566 * Release a reference to the @tty device and if need be let the kref layer
1567 * destruct the object for us.
1568 */
1569void tty_kref_put(struct tty_struct *tty)
1570{
1571 if (tty)
1572 kref_put(&tty->kref, queue_release_one_tty);
1573}
1574EXPORT_SYMBOL(tty_kref_put);
1575
1576/**
1577 * release_tty - release tty structure memory
1578 * @tty: tty device release
1579 * @idx: index of the tty device release
1580 *
1581 * Release both @tty and a possible linked partner (think pty pair),
1582 * and decrement the refcount of the backing module.
1583 *
1584 * Locking:
1585 * tty_mutex
1586 * takes the file list lock internally when working on the list of ttys
1587 * that the driver keeps.
1588 */
1589static void release_tty(struct tty_struct *tty, int idx)
1590{
1591 /* This should always be true but check for the moment */
1592 WARN_ON(tty->index != idx);
1593 WARN_ON(!mutex_is_locked(&tty_mutex));
1594 if (tty->ops->shutdown)
1595 tty->ops->shutdown(tty);
1596 tty_save_termios(tty);
1597 tty_driver_remove_tty(tty->driver, tty);
1598 if (tty->port)
1599 tty->port->itty = NULL;
1600 if (tty->link)
1601 tty->link->port->itty = NULL;
1602 if (tty->port)
1603 tty_buffer_cancel_work(tty->port);
1604 if (tty->link)
1605 tty_buffer_cancel_work(tty->link->port);
1606
1607 tty_kref_put(tty->link);
1608 tty_kref_put(tty);
1609}
1610
1611/**
1612 * tty_release_checks - check a tty before real release
1613 * @tty: tty to check
1614 * @idx: index of the tty
1615 *
1616 * Performs some paranoid checking before true release of the @tty. This is a
1617 * no-op unless %TTY_PARANOIA_CHECK is defined.
1618 */
1619static int tty_release_checks(struct tty_struct *tty, int idx)
1620{
1621#ifdef TTY_PARANOIA_CHECK
1622 if (idx < 0 || idx >= tty->driver->num) {
1623 tty_debug(tty, "bad idx %d\n", idx);
1624 return -1;
1625 }
1626
1627 /* not much to check for devpts */
1628 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1629 return 0;
1630
1631 if (tty != tty->driver->ttys[idx]) {
1632 tty_debug(tty, "bad driver table[%d] = %p\n",
1633 idx, tty->driver->ttys[idx]);
1634 return -1;
1635 }
1636 if (tty->driver->other) {
1637 struct tty_struct *o_tty = tty->link;
1638
1639 if (o_tty != tty->driver->other->ttys[idx]) {
1640 tty_debug(tty, "bad other table[%d] = %p\n",
1641 idx, tty->driver->other->ttys[idx]);
1642 return -1;
1643 }
1644 if (o_tty->link != tty) {
1645 tty_debug(tty, "bad link = %p\n", o_tty->link);
1646 return -1;
1647 }
1648 }
1649#endif
1650 return 0;
1651}
1652
1653/**
1654 * tty_kclose - closes tty opened by tty_kopen
1655 * @tty: tty device
1656 *
1657 * Performs the final steps to release and free a tty device. It is the same as
1658 * tty_release_struct() except that it also resets %TTY_PORT_KOPENED flag on
1659 * @tty->port.
1660 */
1661void tty_kclose(struct tty_struct *tty)
1662{
1663 /*
1664 * Ask the line discipline code to release its structures
1665 */
1666 tty_ldisc_release(tty);
1667
1668 /* Wait for pending work before tty destruction commences */
1669 tty_flush_works(tty);
1670
1671 tty_debug_hangup(tty, "freeing structure\n");
1672 /*
1673 * The release_tty function takes care of the details of clearing
1674 * the slots and preserving the termios structure.
1675 */
1676 mutex_lock(&tty_mutex);
1677 tty_port_set_kopened(tty->port, 0);
1678 release_tty(tty, tty->index);
1679 mutex_unlock(&tty_mutex);
1680}
1681EXPORT_SYMBOL_GPL(tty_kclose);
1682
1683/**
1684 * tty_release_struct - release a tty struct
1685 * @tty: tty device
1686 * @idx: index of the tty
1687 *
1688 * Performs the final steps to release and free a tty device. It is roughly the
1689 * reverse of tty_init_dev().
1690 */
1691void tty_release_struct(struct tty_struct *tty, int idx)
1692{
1693 /*
1694 * Ask the line discipline code to release its structures
1695 */
1696 tty_ldisc_release(tty);
1697
1698 /* Wait for pending work before tty destruction commmences */
1699 tty_flush_works(tty);
1700
1701 tty_debug_hangup(tty, "freeing structure\n");
1702 /*
1703 * The release_tty function takes care of the details of clearing
1704 * the slots and preserving the termios structure.
1705 */
1706 mutex_lock(&tty_mutex);
1707 release_tty(tty, idx);
1708 mutex_unlock(&tty_mutex);
1709}
1710EXPORT_SYMBOL_GPL(tty_release_struct);
1711
1712/**
1713 * tty_release - vfs callback for close
1714 * @inode: inode of tty
1715 * @filp: file pointer for handle to tty
1716 *
1717 * Called the last time each file handle is closed that references this tty.
1718 * There may however be several such references.
1719 *
1720 * Locking:
1721 * Takes BKL. See tty_release_dev().
1722 *
1723 * Even releasing the tty structures is a tricky business. We have to be very
1724 * careful that the structures are all released at the same time, as interrupts
1725 * might otherwise get the wrong pointers.
1726 *
1727 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1728 * lead to double frees or releasing memory still in use.
1729 */
1730int tty_release(struct inode *inode, struct file *filp)
1731{
1732 struct tty_struct *tty = file_tty(filp);
1733 struct tty_struct *o_tty = NULL;
1734 int do_sleep, final;
1735 int idx;
1736 long timeout = 0;
1737 int once = 1;
1738
1739 if (tty_paranoia_check(tty, inode, __func__))
1740 return 0;
1741
1742 tty_lock(tty);
1743 check_tty_count(tty, __func__);
1744
1745 __tty_fasync(-1, filp, 0);
1746
1747 idx = tty->index;
1748 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1749 tty->driver->subtype == PTY_TYPE_MASTER)
1750 o_tty = tty->link;
1751
1752 if (tty_release_checks(tty, idx)) {
1753 tty_unlock(tty);
1754 return 0;
1755 }
1756
1757 tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count);
1758
1759 if (tty->ops->close)
1760 tty->ops->close(tty, filp);
1761
1762 /* If tty is pty master, lock the slave pty (stable lock order) */
1763 tty_lock_slave(o_tty);
1764
1765 /*
1766 * Sanity check: if tty->count is going to zero, there shouldn't be
1767 * any waiters on tty->read_wait or tty->write_wait. We test the
1768 * wait queues and kick everyone out _before_ actually starting to
1769 * close. This ensures that we won't block while releasing the tty
1770 * structure.
1771 *
1772 * The test for the o_tty closing is necessary, since the master and
1773 * slave sides may close in any order. If the slave side closes out
1774 * first, its count will be one, since the master side holds an open.
1775 * Thus this test wouldn't be triggered at the time the slave closed,
1776 * so we do it now.
1777 */
1778 while (1) {
1779 do_sleep = 0;
1780
1781 if (tty->count <= 1) {
1782 if (waitqueue_active(&tty->read_wait)) {
1783 wake_up_poll(&tty->read_wait, EPOLLIN);
1784 do_sleep++;
1785 }
1786 if (waitqueue_active(&tty->write_wait)) {
1787 wake_up_poll(&tty->write_wait, EPOLLOUT);
1788 do_sleep++;
1789 }
1790 }
1791 if (o_tty && o_tty->count <= 1) {
1792 if (waitqueue_active(&o_tty->read_wait)) {
1793 wake_up_poll(&o_tty->read_wait, EPOLLIN);
1794 do_sleep++;
1795 }
1796 if (waitqueue_active(&o_tty->write_wait)) {
1797 wake_up_poll(&o_tty->write_wait, EPOLLOUT);
1798 do_sleep++;
1799 }
1800 }
1801 if (!do_sleep)
1802 break;
1803
1804 if (once) {
1805 once = 0;
1806 tty_warn(tty, "read/write wait queue active!\n");
1807 }
1808 schedule_timeout_killable(timeout);
1809 if (timeout < 120 * HZ)
1810 timeout = 2 * timeout + 1;
1811 else
1812 timeout = MAX_SCHEDULE_TIMEOUT;
1813 }
1814
1815 if (o_tty) {
1816 if (--o_tty->count < 0) {
1817 tty_warn(tty, "bad slave count (%d)\n", o_tty->count);
1818 o_tty->count = 0;
1819 }
1820 }
1821 if (--tty->count < 0) {
1822 tty_warn(tty, "bad tty->count (%d)\n", tty->count);
1823 tty->count = 0;
1824 }
1825
1826 /*
1827 * We've decremented tty->count, so we need to remove this file
1828 * descriptor off the tty->tty_files list; this serves two
1829 * purposes:
1830 * - check_tty_count sees the correct number of file descriptors
1831 * associated with this tty.
1832 * - do_tty_hangup no longer sees this file descriptor as
1833 * something that needs to be handled for hangups.
1834 */
1835 tty_del_file(filp);
1836
1837 /*
1838 * Perform some housekeeping before deciding whether to return.
1839 *
1840 * If _either_ side is closing, make sure there aren't any
1841 * processes that still think tty or o_tty is their controlling
1842 * tty.
1843 */
1844 if (!tty->count) {
1845 read_lock(&tasklist_lock);
1846 session_clear_tty(tty->ctrl.session);
1847 if (o_tty)
1848 session_clear_tty(o_tty->ctrl.session);
1849 read_unlock(&tasklist_lock);
1850 }
1851
1852 /* check whether both sides are closing ... */
1853 final = !tty->count && !(o_tty && o_tty->count);
1854
1855 tty_unlock_slave(o_tty);
1856 tty_unlock(tty);
1857
1858 /* At this point, the tty->count == 0 should ensure a dead tty
1859 * cannot be re-opened by a racing opener.
1860 */
1861
1862 if (!final)
1863 return 0;
1864
1865 tty_debug_hangup(tty, "final close\n");
1866
1867 tty_release_struct(tty, idx);
1868 return 0;
1869}
1870
1871/**
1872 * tty_open_current_tty - get locked tty of current task
1873 * @device: device number
1874 * @filp: file pointer to tty
1875 * @return: locked tty of the current task iff @device is /dev/tty
1876 *
1877 * Performs a re-open of the current task's controlling tty.
1878 *
1879 * We cannot return driver and index like for the other nodes because devpts
1880 * will not work then. It expects inodes to be from devpts FS.
1881 */
1882static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1883{
1884 struct tty_struct *tty;
1885 int retval;
1886
1887 if (device != MKDEV(TTYAUX_MAJOR, 0))
1888 return NULL;
1889
1890 tty = get_current_tty();
1891 if (!tty)
1892 return ERR_PTR(-ENXIO);
1893
1894 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1895 /* noctty = 1; */
1896 tty_lock(tty);
1897 tty_kref_put(tty); /* safe to drop the kref now */
1898
1899 retval = tty_reopen(tty);
1900 if (retval < 0) {
1901 tty_unlock(tty);
1902 tty = ERR_PTR(retval);
1903 }
1904 return tty;
1905}
1906
1907/**
1908 * tty_lookup_driver - lookup a tty driver for a given device file
1909 * @device: device number
1910 * @filp: file pointer to tty
1911 * @index: index for the device in the @return driver
1912 *
1913 * If returned value is not erroneous, the caller is responsible to decrement
1914 * the refcount by tty_driver_kref_put().
1915 *
1916 * Locking: %tty_mutex protects get_tty_driver()
1917 *
1918 * Return: driver for this inode (with increased refcount)
1919 */
1920static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1921 int *index)
1922{
1923 struct tty_driver *driver = NULL;
1924
1925 switch (device) {
1926#ifdef CONFIG_VT
1927 case MKDEV(TTY_MAJOR, 0): {
1928 extern struct tty_driver *console_driver;
1929
1930 driver = tty_driver_kref_get(console_driver);
1931 *index = fg_console;
1932 break;
1933 }
1934#endif
1935 case MKDEV(TTYAUX_MAJOR, 1): {
1936 struct tty_driver *console_driver = console_device(index);
1937
1938 if (console_driver) {
1939 driver = tty_driver_kref_get(console_driver);
1940 if (driver && filp) {
1941 /* Don't let /dev/console block */
1942 filp->f_flags |= O_NONBLOCK;
1943 break;
1944 }
1945 }
1946 if (driver)
1947 tty_driver_kref_put(driver);
1948 return ERR_PTR(-ENODEV);
1949 }
1950 default:
1951 driver = get_tty_driver(device, index);
1952 if (!driver)
1953 return ERR_PTR(-ENODEV);
1954 break;
1955 }
1956 return driver;
1957}
1958
1959static struct tty_struct *tty_kopen(dev_t device, int shared)
1960{
1961 struct tty_struct *tty;
1962 struct tty_driver *driver;
1963 int index = -1;
1964
1965 mutex_lock(&tty_mutex);
1966 driver = tty_lookup_driver(device, NULL, &index);
1967 if (IS_ERR(driver)) {
1968 mutex_unlock(&tty_mutex);
1969 return ERR_CAST(driver);
1970 }
1971
1972 /* check whether we're reopening an existing tty */
1973 tty = tty_driver_lookup_tty(driver, NULL, index);
1974 if (IS_ERR(tty) || shared)
1975 goto out;
1976
1977 if (tty) {
1978 /* drop kref from tty_driver_lookup_tty() */
1979 tty_kref_put(tty);
1980 tty = ERR_PTR(-EBUSY);
1981 } else { /* tty_init_dev returns tty with the tty_lock held */
1982 tty = tty_init_dev(driver, index);
1983 if (IS_ERR(tty))
1984 goto out;
1985 tty_port_set_kopened(tty->port, 1);
1986 }
1987out:
1988 mutex_unlock(&tty_mutex);
1989 tty_driver_kref_put(driver);
1990 return tty;
1991}
1992
1993/**
1994 * tty_kopen_exclusive - open a tty device for kernel
1995 * @device: dev_t of device to open
1996 *
1997 * Opens tty exclusively for kernel. Performs the driver lookup, makes sure
1998 * it's not already opened and performs the first-time tty initialization.
1999 *
2000 * Claims the global %tty_mutex to serialize:
2001 * * concurrent first-time tty initialization
2002 * * concurrent tty driver removal w/ lookup
2003 * * concurrent tty removal from driver table
2004 *
2005 * Return: the locked initialized &tty_struct
2006 */
2007struct tty_struct *tty_kopen_exclusive(dev_t device)
2008{
2009 return tty_kopen(device, 0);
2010}
2011EXPORT_SYMBOL_GPL(tty_kopen_exclusive);
2012
2013/**
2014 * tty_kopen_shared - open a tty device for shared in-kernel use
2015 * @device: dev_t of device to open
2016 *
2017 * Opens an already existing tty for in-kernel use. Compared to
2018 * tty_kopen_exclusive() above it doesn't ensure to be the only user.
2019 *
2020 * Locking: identical to tty_kopen() above.
2021 */
2022struct tty_struct *tty_kopen_shared(dev_t device)
2023{
2024 return tty_kopen(device, 1);
2025}
2026EXPORT_SYMBOL_GPL(tty_kopen_shared);
2027
2028/**
2029 * tty_open_by_driver - open a tty device
2030 * @device: dev_t of device to open
2031 * @filp: file pointer to tty
2032 *
2033 * Performs the driver lookup, checks for a reopen, or otherwise performs the
2034 * first-time tty initialization.
2035 *
2036 *
2037 * Claims the global tty_mutex to serialize:
2038 * * concurrent first-time tty initialization
2039 * * concurrent tty driver removal w/ lookup
2040 * * concurrent tty removal from driver table
2041 *
2042 * Return: the locked initialized or re-opened &tty_struct
2043 */
2044static struct tty_struct *tty_open_by_driver(dev_t device,
2045 struct file *filp)
2046{
2047 struct tty_struct *tty;
2048 struct tty_driver *driver = NULL;
2049 int index = -1;
2050 int retval;
2051
2052 mutex_lock(&tty_mutex);
2053 driver = tty_lookup_driver(device, filp, &index);
2054 if (IS_ERR(driver)) {
2055 mutex_unlock(&tty_mutex);
2056 return ERR_CAST(driver);
2057 }
2058
2059 /* check whether we're reopening an existing tty */
2060 tty = tty_driver_lookup_tty(driver, filp, index);
2061 if (IS_ERR(tty)) {
2062 mutex_unlock(&tty_mutex);
2063 goto out;
2064 }
2065
2066 if (tty) {
2067 if (tty_port_kopened(tty->port)) {
2068 tty_kref_put(tty);
2069 mutex_unlock(&tty_mutex);
2070 tty = ERR_PTR(-EBUSY);
2071 goto out;
2072 }
2073 mutex_unlock(&tty_mutex);
2074 retval = tty_lock_interruptible(tty);
2075 tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
2076 if (retval) {
2077 if (retval == -EINTR)
2078 retval = -ERESTARTSYS;
2079 tty = ERR_PTR(retval);
2080 goto out;
2081 }
2082 retval = tty_reopen(tty);
2083 if (retval < 0) {
2084 tty_unlock(tty);
2085 tty = ERR_PTR(retval);
2086 }
2087 } else { /* Returns with the tty_lock held for now */
2088 tty = tty_init_dev(driver, index);
2089 mutex_unlock(&tty_mutex);
2090 }
2091out:
2092 tty_driver_kref_put(driver);
2093 return tty;
2094}
2095
2096/**
2097 * tty_open - open a tty device
2098 * @inode: inode of device file
2099 * @filp: file pointer to tty
2100 *
2101 * tty_open() and tty_release() keep up the tty count that contains the number
2102 * of opens done on a tty. We cannot use the inode-count, as different inodes
2103 * might point to the same tty.
2104 *
2105 * Open-counting is needed for pty masters, as well as for keeping track of
2106 * serial lines: DTR is dropped when the last close happens.
2107 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2108 *
2109 * The termios state of a pty is reset on the first open so that settings don't
2110 * persist across reuse.
2111 *
2112 * Locking:
2113 * * %tty_mutex protects tty, tty_lookup_driver() and tty_init_dev().
2114 * * @tty->count should protect the rest.
2115 * * ->siglock protects ->signal/->sighand
2116 *
2117 * Note: the tty_unlock/lock cases without a ref are only safe due to %tty_mutex
2118 */
2119static int tty_open(struct inode *inode, struct file *filp)
2120{
2121 struct tty_struct *tty;
2122 int noctty, retval;
2123 dev_t device = inode->i_rdev;
2124 unsigned saved_flags = filp->f_flags;
2125
2126 nonseekable_open(inode, filp);
2127
2128retry_open:
2129 retval = tty_alloc_file(filp);
2130 if (retval)
2131 return -ENOMEM;
2132
2133 tty = tty_open_current_tty(device, filp);
2134 if (!tty)
2135 tty = tty_open_by_driver(device, filp);
2136
2137 if (IS_ERR(tty)) {
2138 tty_free_file(filp);
2139 retval = PTR_ERR(tty);
2140 if (retval != -EAGAIN || signal_pending(current))
2141 return retval;
2142 schedule();
2143 goto retry_open;
2144 }
2145
2146 tty_add_file(tty, filp);
2147
2148 check_tty_count(tty, __func__);
2149 tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
2150
2151 if (tty->ops->open)
2152 retval = tty->ops->open(tty, filp);
2153 else
2154 retval = -ENODEV;
2155 filp->f_flags = saved_flags;
2156
2157 if (retval) {
2158 tty_debug_hangup(tty, "open error %d, releasing\n", retval);
2159
2160 tty_unlock(tty); /* need to call tty_release without BTM */
2161 tty_release(inode, filp);
2162 if (retval != -ERESTARTSYS)
2163 return retval;
2164
2165 if (signal_pending(current))
2166 return retval;
2167
2168 schedule();
2169 /*
2170 * Need to reset f_op in case a hangup happened.
2171 */
2172 if (tty_hung_up_p(filp))
2173 filp->f_op = &tty_fops;
2174 goto retry_open;
2175 }
2176 clear_bit(TTY_HUPPED, &tty->flags);
2177
2178 noctty = (filp->f_flags & O_NOCTTY) ||
2179 (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) ||
2180 device == MKDEV(TTYAUX_MAJOR, 1) ||
2181 (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2182 tty->driver->subtype == PTY_TYPE_MASTER);
2183 if (!noctty)
2184 tty_open_proc_set_tty(filp, tty);
2185 tty_unlock(tty);
2186 return 0;
2187}
2188
2189
2190/**
2191 * tty_poll - check tty status
2192 * @filp: file being polled
2193 * @wait: poll wait structures to update
2194 *
2195 * Call the line discipline polling method to obtain the poll status of the
2196 * device.
2197 *
2198 * Locking: locks called line discipline but ldisc poll method may be
2199 * re-entered freely by other callers.
2200 */
2201static __poll_t tty_poll(struct file *filp, poll_table *wait)
2202{
2203 struct tty_struct *tty = file_tty(filp);
2204 struct tty_ldisc *ld;
2205 __poll_t ret = 0;
2206
2207 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2208 return 0;
2209
2210 ld = tty_ldisc_ref_wait(tty);
2211 if (!ld)
2212 return hung_up_tty_poll(filp, wait);
2213 if (ld->ops->poll)
2214 ret = ld->ops->poll(tty, filp, wait);
2215 tty_ldisc_deref(ld);
2216 return ret;
2217}
2218
2219static int __tty_fasync(int fd, struct file *filp, int on)
2220{
2221 struct tty_struct *tty = file_tty(filp);
2222 unsigned long flags;
2223 int retval = 0;
2224
2225 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2226 goto out;
2227
2228 retval = fasync_helper(fd, filp, on, &tty->fasync);
2229 if (retval <= 0)
2230 goto out;
2231
2232 if (on) {
2233 enum pid_type type;
2234 struct pid *pid;
2235
2236 spin_lock_irqsave(&tty->ctrl.lock, flags);
2237 if (tty->ctrl.pgrp) {
2238 pid = tty->ctrl.pgrp;
2239 type = PIDTYPE_PGID;
2240 } else {
2241 pid = task_pid(current);
2242 type = PIDTYPE_TGID;
2243 }
2244 get_pid(pid);
2245 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
2246 __f_setown(filp, pid, type, 0);
2247 put_pid(pid);
2248 retval = 0;
2249 }
2250out:
2251 return retval;
2252}
2253
2254static int tty_fasync(int fd, struct file *filp, int on)
2255{
2256 struct tty_struct *tty = file_tty(filp);
2257 int retval = -ENOTTY;
2258
2259 tty_lock(tty);
2260 if (!tty_hung_up_p(filp))
2261 retval = __tty_fasync(fd, filp, on);
2262 tty_unlock(tty);
2263
2264 return retval;
2265}
2266
2267static bool tty_legacy_tiocsti __read_mostly = IS_ENABLED(CONFIG_LEGACY_TIOCSTI);
2268/**
2269 * tiocsti - fake input character
2270 * @tty: tty to fake input into
2271 * @p: pointer to character
2272 *
2273 * Fake input to a tty device. Does the necessary locking and input management.
2274 *
2275 * FIXME: does not honour flow control ??
2276 *
2277 * Locking:
2278 * * Called functions take tty_ldiscs_lock
2279 * * current->signal->tty check is safe without locks
2280 */
2281static int tiocsti(struct tty_struct *tty, u8 __user *p)
2282{
2283 struct tty_ldisc *ld;
2284 u8 ch;
2285
2286 if (!tty_legacy_tiocsti && !capable(CAP_SYS_ADMIN))
2287 return -EIO;
2288
2289 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2290 return -EPERM;
2291 if (get_user(ch, p))
2292 return -EFAULT;
2293 tty_audit_tiocsti(tty, ch);
2294 ld = tty_ldisc_ref_wait(tty);
2295 if (!ld)
2296 return -EIO;
2297 tty_buffer_lock_exclusive(tty->port);
2298 if (ld->ops->receive_buf)
2299 ld->ops->receive_buf(tty, &ch, NULL, 1);
2300 tty_buffer_unlock_exclusive(tty->port);
2301 tty_ldisc_deref(ld);
2302 return 0;
2303}
2304
2305/**
2306 * tiocgwinsz - implement window query ioctl
2307 * @tty: tty
2308 * @arg: user buffer for result
2309 *
2310 * Copies the kernel idea of the window size into the user buffer.
2311 *
2312 * Locking: @tty->winsize_mutex is taken to ensure the winsize data is
2313 * consistent.
2314 */
2315static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2316{
2317 int err;
2318
2319 mutex_lock(&tty->winsize_mutex);
2320 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2321 mutex_unlock(&tty->winsize_mutex);
2322
2323 return err ? -EFAULT : 0;
2324}
2325
2326/**
2327 * tty_do_resize - resize event
2328 * @tty: tty being resized
2329 * @ws: new dimensions
2330 *
2331 * Update the termios variables and send the necessary signals to peform a
2332 * terminal resize correctly.
2333 */
2334int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2335{
2336 struct pid *pgrp;
2337
2338 /* Lock the tty */
2339 mutex_lock(&tty->winsize_mutex);
2340 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2341 goto done;
2342
2343 /* Signal the foreground process group */
2344 pgrp = tty_get_pgrp(tty);
2345 if (pgrp)
2346 kill_pgrp(pgrp, SIGWINCH, 1);
2347 put_pid(pgrp);
2348
2349 tty->winsize = *ws;
2350done:
2351 mutex_unlock(&tty->winsize_mutex);
2352 return 0;
2353}
2354EXPORT_SYMBOL(tty_do_resize);
2355
2356/**
2357 * tiocswinsz - implement window size set ioctl
2358 * @tty: tty side of tty
2359 * @arg: user buffer for result
2360 *
2361 * Copies the user idea of the window size to the kernel. Traditionally this is
2362 * just advisory information but for the Linux console it actually has driver
2363 * level meaning and triggers a VC resize.
2364 *
2365 * Locking:
2366 * Driver dependent. The default do_resize method takes the tty termios
2367 * mutex and ctrl.lock. The console takes its own lock then calls into the
2368 * default method.
2369 */
2370static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2371{
2372 struct winsize tmp_ws;
2373
2374 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2375 return -EFAULT;
2376
2377 if (tty->ops->resize)
2378 return tty->ops->resize(tty, &tmp_ws);
2379 else
2380 return tty_do_resize(tty, &tmp_ws);
2381}
2382
2383/**
2384 * tioccons - allow admin to move logical console
2385 * @file: the file to become console
2386 *
2387 * Allow the administrator to move the redirected console device.
2388 *
2389 * Locking: uses redirect_lock to guard the redirect information
2390 */
2391static int tioccons(struct file *file)
2392{
2393 if (!capable(CAP_SYS_ADMIN))
2394 return -EPERM;
2395 if (file->f_op->write_iter == redirected_tty_write) {
2396 struct file *f;
2397
2398 spin_lock(&redirect_lock);
2399 f = redirect;
2400 redirect = NULL;
2401 spin_unlock(&redirect_lock);
2402 if (f)
2403 fput(f);
2404 return 0;
2405 }
2406 if (file->f_op->write_iter != tty_write)
2407 return -ENOTTY;
2408 if (!(file->f_mode & FMODE_WRITE))
2409 return -EBADF;
2410 if (!(file->f_mode & FMODE_CAN_WRITE))
2411 return -EINVAL;
2412 spin_lock(&redirect_lock);
2413 if (redirect) {
2414 spin_unlock(&redirect_lock);
2415 return -EBUSY;
2416 }
2417 redirect = get_file(file);
2418 spin_unlock(&redirect_lock);
2419 return 0;
2420}
2421
2422/**
2423 * tiocsetd - set line discipline
2424 * @tty: tty device
2425 * @p: pointer to user data
2426 *
2427 * Set the line discipline according to user request.
2428 *
2429 * Locking: see tty_set_ldisc(), this function is just a helper
2430 */
2431static int tiocsetd(struct tty_struct *tty, int __user *p)
2432{
2433 int disc;
2434 int ret;
2435
2436 if (get_user(disc, p))
2437 return -EFAULT;
2438
2439 ret = tty_set_ldisc(tty, disc);
2440
2441 return ret;
2442}
2443
2444/**
2445 * tiocgetd - get line discipline
2446 * @tty: tty device
2447 * @p: pointer to user data
2448 *
2449 * Retrieves the line discipline id directly from the ldisc.
2450 *
2451 * Locking: waits for ldisc reference (in case the line discipline is changing
2452 * or the @tty is being hungup)
2453 */
2454static int tiocgetd(struct tty_struct *tty, int __user *p)
2455{
2456 struct tty_ldisc *ld;
2457 int ret;
2458
2459 ld = tty_ldisc_ref_wait(tty);
2460 if (!ld)
2461 return -EIO;
2462 ret = put_user(ld->ops->num, p);
2463 tty_ldisc_deref(ld);
2464 return ret;
2465}
2466
2467/**
2468 * send_break - performed time break
2469 * @tty: device to break on
2470 * @duration: timeout in mS
2471 *
2472 * Perform a timed break on hardware that lacks its own driver level timed
2473 * break functionality.
2474 *
2475 * Locking:
2476 * @tty->atomic_write_lock serializes
2477 */
2478static int send_break(struct tty_struct *tty, unsigned int duration)
2479{
2480 int retval;
2481
2482 if (tty->ops->break_ctl == NULL)
2483 return 0;
2484
2485 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2486 return tty->ops->break_ctl(tty, duration);
2487
2488 /* Do the work ourselves */
2489 if (tty_write_lock(tty, false) < 0)
2490 return -EINTR;
2491
2492 retval = tty->ops->break_ctl(tty, -1);
2493 if (!retval) {
2494 msleep_interruptible(duration);
2495 retval = tty->ops->break_ctl(tty, 0);
2496 } else if (retval == -EOPNOTSUPP) {
2497 /* some drivers can tell only dynamically */
2498 retval = 0;
2499 }
2500 tty_write_unlock(tty);
2501
2502 if (signal_pending(current))
2503 retval = -EINTR;
2504
2505 return retval;
2506}
2507
2508/**
2509 * tty_get_tiocm - get tiocm status register
2510 * @tty: tty device
2511 *
2512 * Obtain the modem status bits from the tty driver if the feature
2513 * is supported.
2514 */
2515int tty_get_tiocm(struct tty_struct *tty)
2516{
2517 int retval = -ENOTTY;
2518
2519 if (tty->ops->tiocmget)
2520 retval = tty->ops->tiocmget(tty);
2521
2522 return retval;
2523}
2524EXPORT_SYMBOL_GPL(tty_get_tiocm);
2525
2526/**
2527 * tty_tiocmget - get modem status
2528 * @tty: tty device
2529 * @p: pointer to result
2530 *
2531 * Obtain the modem status bits from the tty driver if the feature is
2532 * supported. Return -%ENOTTY if it is not available.
2533 *
2534 * Locking: none (up to the driver)
2535 */
2536static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2537{
2538 int retval;
2539
2540 retval = tty_get_tiocm(tty);
2541 if (retval >= 0)
2542 retval = put_user(retval, p);
2543
2544 return retval;
2545}
2546
2547/**
2548 * tty_tiocmset - set modem status
2549 * @tty: tty device
2550 * @cmd: command - clear bits, set bits or set all
2551 * @p: pointer to desired bits
2552 *
2553 * Set the modem status bits from the tty driver if the feature
2554 * is supported. Return -%ENOTTY if it is not available.
2555 *
2556 * Locking: none (up to the driver)
2557 */
2558static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2559 unsigned __user *p)
2560{
2561 int retval;
2562 unsigned int set, clear, val;
2563
2564 if (tty->ops->tiocmset == NULL)
2565 return -ENOTTY;
2566
2567 retval = get_user(val, p);
2568 if (retval)
2569 return retval;
2570 set = clear = 0;
2571 switch (cmd) {
2572 case TIOCMBIS:
2573 set = val;
2574 break;
2575 case TIOCMBIC:
2576 clear = val;
2577 break;
2578 case TIOCMSET:
2579 set = val;
2580 clear = ~val;
2581 break;
2582 }
2583 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2584 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2585 return tty->ops->tiocmset(tty, set, clear);
2586}
2587
2588/**
2589 * tty_get_icount - get tty statistics
2590 * @tty: tty device
2591 * @icount: output parameter
2592 *
2593 * Gets a copy of the @tty's icount statistics.
2594 *
2595 * Locking: none (up to the driver)
2596 */
2597int tty_get_icount(struct tty_struct *tty,
2598 struct serial_icounter_struct *icount)
2599{
2600 memset(icount, 0, sizeof(*icount));
2601
2602 if (tty->ops->get_icount)
2603 return tty->ops->get_icount(tty, icount);
2604 else
2605 return -ENOTTY;
2606}
2607EXPORT_SYMBOL_GPL(tty_get_icount);
2608
2609static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2610{
2611 struct serial_icounter_struct icount;
2612 int retval;
2613
2614 retval = tty_get_icount(tty, &icount);
2615 if (retval != 0)
2616 return retval;
2617
2618 if (copy_to_user(arg, &icount, sizeof(icount)))
2619 return -EFAULT;
2620 return 0;
2621}
2622
2623static int tty_set_serial(struct tty_struct *tty, struct serial_struct *ss)
2624{
2625 char comm[TASK_COMM_LEN];
2626 int flags;
2627
2628 flags = ss->flags & ASYNC_DEPRECATED;
2629
2630 if (flags)
2631 pr_warn_ratelimited("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n",
2632 __func__, get_task_comm(comm, current), flags);
2633
2634 if (!tty->ops->set_serial)
2635 return -ENOTTY;
2636
2637 return tty->ops->set_serial(tty, ss);
2638}
2639
2640static int tty_tiocsserial(struct tty_struct *tty, struct serial_struct __user *ss)
2641{
2642 struct serial_struct v;
2643
2644 if (copy_from_user(&v, ss, sizeof(*ss)))
2645 return -EFAULT;
2646
2647 return tty_set_serial(tty, &v);
2648}
2649
2650static int tty_tiocgserial(struct tty_struct *tty, struct serial_struct __user *ss)
2651{
2652 struct serial_struct v;
2653 int err;
2654
2655 memset(&v, 0, sizeof(v));
2656 if (!tty->ops->get_serial)
2657 return -ENOTTY;
2658 err = tty->ops->get_serial(tty, &v);
2659 if (!err && copy_to_user(ss, &v, sizeof(v)))
2660 err = -EFAULT;
2661 return err;
2662}
2663
2664/*
2665 * if pty, return the slave side (real_tty)
2666 * otherwise, return self
2667 */
2668static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2669{
2670 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2671 tty->driver->subtype == PTY_TYPE_MASTER)
2672 tty = tty->link;
2673 return tty;
2674}
2675
2676/*
2677 * Split this up, as gcc can choke on it otherwise..
2678 */
2679long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2680{
2681 struct tty_struct *tty = file_tty(file);
2682 struct tty_struct *real_tty;
2683 void __user *p = (void __user *)arg;
2684 int retval;
2685 struct tty_ldisc *ld;
2686
2687 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2688 return -EINVAL;
2689
2690 real_tty = tty_pair_get_tty(tty);
2691
2692 /*
2693 * Factor out some common prep work
2694 */
2695 switch (cmd) {
2696 case TIOCSETD:
2697 case TIOCSBRK:
2698 case TIOCCBRK:
2699 case TCSBRK:
2700 case TCSBRKP:
2701 retval = tty_check_change(tty);
2702 if (retval)
2703 return retval;
2704 if (cmd != TIOCCBRK) {
2705 tty_wait_until_sent(tty, 0);
2706 if (signal_pending(current))
2707 return -EINTR;
2708 }
2709 break;
2710 }
2711
2712 /*
2713 * Now do the stuff.
2714 */
2715 switch (cmd) {
2716 case TIOCSTI:
2717 return tiocsti(tty, p);
2718 case TIOCGWINSZ:
2719 return tiocgwinsz(real_tty, p);
2720 case TIOCSWINSZ:
2721 return tiocswinsz(real_tty, p);
2722 case TIOCCONS:
2723 return real_tty != tty ? -EINVAL : tioccons(file);
2724 case TIOCEXCL:
2725 set_bit(TTY_EXCLUSIVE, &tty->flags);
2726 return 0;
2727 case TIOCNXCL:
2728 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2729 return 0;
2730 case TIOCGEXCL:
2731 {
2732 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2733
2734 return put_user(excl, (int __user *)p);
2735 }
2736 case TIOCGETD:
2737 return tiocgetd(tty, p);
2738 case TIOCSETD:
2739 return tiocsetd(tty, p);
2740 case TIOCVHANGUP:
2741 if (!capable(CAP_SYS_ADMIN))
2742 return -EPERM;
2743 tty_vhangup(tty);
2744 return 0;
2745 case TIOCGDEV:
2746 {
2747 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2748
2749 return put_user(ret, (unsigned int __user *)p);
2750 }
2751 /*
2752 * Break handling
2753 */
2754 case TIOCSBRK: /* Turn break on, unconditionally */
2755 if (tty->ops->break_ctl)
2756 return tty->ops->break_ctl(tty, -1);
2757 return 0;
2758 case TIOCCBRK: /* Turn break off, unconditionally */
2759 if (tty->ops->break_ctl)
2760 return tty->ops->break_ctl(tty, 0);
2761 return 0;
2762 case TCSBRK: /* SVID version: non-zero arg --> no break */
2763 /* non-zero arg means wait for all output data
2764 * to be sent (performed above) but don't send break.
2765 * This is used by the tcdrain() termios function.
2766 */
2767 if (!arg)
2768 return send_break(tty, 250);
2769 return 0;
2770 case TCSBRKP: /* support for POSIX tcsendbreak() */
2771 return send_break(tty, arg ? arg*100 : 250);
2772
2773 case TIOCMGET:
2774 return tty_tiocmget(tty, p);
2775 case TIOCMSET:
2776 case TIOCMBIC:
2777 case TIOCMBIS:
2778 return tty_tiocmset(tty, cmd, p);
2779 case TIOCGICOUNT:
2780 return tty_tiocgicount(tty, p);
2781 case TCFLSH:
2782 switch (arg) {
2783 case TCIFLUSH:
2784 case TCIOFLUSH:
2785 /* flush tty buffer and allow ldisc to process ioctl */
2786 tty_buffer_flush(tty, NULL);
2787 break;
2788 }
2789 break;
2790 case TIOCSSERIAL:
2791 return tty_tiocsserial(tty, p);
2792 case TIOCGSERIAL:
2793 return tty_tiocgserial(tty, p);
2794 case TIOCGPTPEER:
2795 /* Special because the struct file is needed */
2796 return ptm_open_peer(file, tty, (int)arg);
2797 default:
2798 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
2799 if (retval != -ENOIOCTLCMD)
2800 return retval;
2801 }
2802 if (tty->ops->ioctl) {
2803 retval = tty->ops->ioctl(tty, cmd, arg);
2804 if (retval != -ENOIOCTLCMD)
2805 return retval;
2806 }
2807 ld = tty_ldisc_ref_wait(tty);
2808 if (!ld)
2809 return hung_up_tty_ioctl(file, cmd, arg);
2810 retval = -EINVAL;
2811 if (ld->ops->ioctl) {
2812 retval = ld->ops->ioctl(tty, cmd, arg);
2813 if (retval == -ENOIOCTLCMD)
2814 retval = -ENOTTY;
2815 }
2816 tty_ldisc_deref(ld);
2817 return retval;
2818}
2819
2820#ifdef CONFIG_COMPAT
2821
2822struct serial_struct32 {
2823 compat_int_t type;
2824 compat_int_t line;
2825 compat_uint_t port;
2826 compat_int_t irq;
2827 compat_int_t flags;
2828 compat_int_t xmit_fifo_size;
2829 compat_int_t custom_divisor;
2830 compat_int_t baud_base;
2831 unsigned short close_delay;
2832 char io_type;
2833 char reserved_char;
2834 compat_int_t hub6;
2835 unsigned short closing_wait; /* time to wait before closing */
2836 unsigned short closing_wait2; /* no longer used... */
2837 compat_uint_t iomem_base;
2838 unsigned short iomem_reg_shift;
2839 unsigned int port_high;
2840 /* compat_ulong_t iomap_base FIXME */
2841 compat_int_t reserved;
2842};
2843
2844static int compat_tty_tiocsserial(struct tty_struct *tty,
2845 struct serial_struct32 __user *ss)
2846{
2847 struct serial_struct32 v32;
2848 struct serial_struct v;
2849
2850 if (copy_from_user(&v32, ss, sizeof(*ss)))
2851 return -EFAULT;
2852
2853 memcpy(&v, &v32, offsetof(struct serial_struct32, iomem_base));
2854 v.iomem_base = compat_ptr(v32.iomem_base);
2855 v.iomem_reg_shift = v32.iomem_reg_shift;
2856 v.port_high = v32.port_high;
2857 v.iomap_base = 0;
2858
2859 return tty_set_serial(tty, &v);
2860}
2861
2862static int compat_tty_tiocgserial(struct tty_struct *tty,
2863 struct serial_struct32 __user *ss)
2864{
2865 struct serial_struct32 v32;
2866 struct serial_struct v;
2867 int err;
2868
2869 memset(&v, 0, sizeof(v));
2870 memset(&v32, 0, sizeof(v32));
2871
2872 if (!tty->ops->get_serial)
2873 return -ENOTTY;
2874 err = tty->ops->get_serial(tty, &v);
2875 if (!err) {
2876 memcpy(&v32, &v, offsetof(struct serial_struct32, iomem_base));
2877 v32.iomem_base = (unsigned long)v.iomem_base >> 32 ?
2878 0xfffffff : ptr_to_compat(v.iomem_base);
2879 v32.iomem_reg_shift = v.iomem_reg_shift;
2880 v32.port_high = v.port_high;
2881 if (copy_to_user(ss, &v32, sizeof(v32)))
2882 err = -EFAULT;
2883 }
2884 return err;
2885}
2886static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2887 unsigned long arg)
2888{
2889 struct tty_struct *tty = file_tty(file);
2890 struct tty_ldisc *ld;
2891 int retval = -ENOIOCTLCMD;
2892
2893 switch (cmd) {
2894 case TIOCOUTQ:
2895 case TIOCSTI:
2896 case TIOCGWINSZ:
2897 case TIOCSWINSZ:
2898 case TIOCGEXCL:
2899 case TIOCGETD:
2900 case TIOCSETD:
2901 case TIOCGDEV:
2902 case TIOCMGET:
2903 case TIOCMSET:
2904 case TIOCMBIC:
2905 case TIOCMBIS:
2906 case TIOCGICOUNT:
2907 case TIOCGPGRP:
2908 case TIOCSPGRP:
2909 case TIOCGSID:
2910 case TIOCSERGETLSR:
2911 case TIOCGRS485:
2912 case TIOCSRS485:
2913#ifdef TIOCGETP
2914 case TIOCGETP:
2915 case TIOCSETP:
2916 case TIOCSETN:
2917#endif
2918#ifdef TIOCGETC
2919 case TIOCGETC:
2920 case TIOCSETC:
2921#endif
2922#ifdef TIOCGLTC
2923 case TIOCGLTC:
2924 case TIOCSLTC:
2925#endif
2926 case TCSETSF:
2927 case TCSETSW:
2928 case TCSETS:
2929 case TCGETS:
2930#ifdef TCGETS2
2931 case TCGETS2:
2932 case TCSETSF2:
2933 case TCSETSW2:
2934 case TCSETS2:
2935#endif
2936 case TCGETA:
2937 case TCSETAF:
2938 case TCSETAW:
2939 case TCSETA:
2940 case TIOCGLCKTRMIOS:
2941 case TIOCSLCKTRMIOS:
2942#ifdef TCGETX
2943 case TCGETX:
2944 case TCSETX:
2945 case TCSETXW:
2946 case TCSETXF:
2947#endif
2948 case TIOCGSOFTCAR:
2949 case TIOCSSOFTCAR:
2950
2951 case PPPIOCGCHAN:
2952 case PPPIOCGUNIT:
2953 return tty_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
2954 case TIOCCONS:
2955 case TIOCEXCL:
2956 case TIOCNXCL:
2957 case TIOCVHANGUP:
2958 case TIOCSBRK:
2959 case TIOCCBRK:
2960 case TCSBRK:
2961 case TCSBRKP:
2962 case TCFLSH:
2963 case TIOCGPTPEER:
2964 case TIOCNOTTY:
2965 case TIOCSCTTY:
2966 case TCXONC:
2967 case TIOCMIWAIT:
2968 case TIOCSERCONFIG:
2969 return tty_ioctl(file, cmd, arg);
2970 }
2971
2972 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2973 return -EINVAL;
2974
2975 switch (cmd) {
2976 case TIOCSSERIAL:
2977 return compat_tty_tiocsserial(tty, compat_ptr(arg));
2978 case TIOCGSERIAL:
2979 return compat_tty_tiocgserial(tty, compat_ptr(arg));
2980 }
2981 if (tty->ops->compat_ioctl) {
2982 retval = tty->ops->compat_ioctl(tty, cmd, arg);
2983 if (retval != -ENOIOCTLCMD)
2984 return retval;
2985 }
2986
2987 ld = tty_ldisc_ref_wait(tty);
2988 if (!ld)
2989 return hung_up_tty_compat_ioctl(file, cmd, arg);
2990 if (ld->ops->compat_ioctl)
2991 retval = ld->ops->compat_ioctl(tty, cmd, arg);
2992 if (retval == -ENOIOCTLCMD && ld->ops->ioctl)
2993 retval = ld->ops->ioctl(tty, (unsigned long)compat_ptr(cmd),
2994 arg);
2995 tty_ldisc_deref(ld);
2996
2997 return retval;
2998}
2999#endif
3000
3001static int this_tty(const void *t, struct file *file, unsigned fd)
3002{
3003 if (likely(file->f_op->read_iter != tty_read))
3004 return 0;
3005 return file_tty(file) != t ? 0 : fd + 1;
3006}
3007
3008/*
3009 * This implements the "Secure Attention Key" --- the idea is to
3010 * prevent trojan horses by killing all processes associated with this
3011 * tty when the user hits the "Secure Attention Key". Required for
3012 * super-paranoid applications --- see the Orange Book for more details.
3013 *
3014 * This code could be nicer; ideally it should send a HUP, wait a few
3015 * seconds, then send a INT, and then a KILL signal. But you then
3016 * have to coordinate with the init process, since all processes associated
3017 * with the current tty must be dead before the new getty is allowed
3018 * to spawn.
3019 *
3020 * Now, if it would be correct ;-/ The current code has a nasty hole -
3021 * it doesn't catch files in flight. We may send the descriptor to ourselves
3022 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3023 *
3024 * Nasty bug: do_SAK is being called in interrupt context. This can
3025 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3026 */
3027void __do_SAK(struct tty_struct *tty)
3028{
3029 struct task_struct *g, *p;
3030 struct pid *session;
3031 int i;
3032 unsigned long flags;
3033
3034 spin_lock_irqsave(&tty->ctrl.lock, flags);
3035 session = get_pid(tty->ctrl.session);
3036 spin_unlock_irqrestore(&tty->ctrl.lock, flags);
3037
3038 tty_ldisc_flush(tty);
3039
3040 tty_driver_flush_buffer(tty);
3041
3042 read_lock(&tasklist_lock);
3043 /* Kill the entire session */
3044 do_each_pid_task(session, PIDTYPE_SID, p) {
3045 tty_notice(tty, "SAK: killed process %d (%s): by session\n",
3046 task_pid_nr(p), p->comm);
3047 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p, PIDTYPE_SID);
3048 } while_each_pid_task(session, PIDTYPE_SID, p);
3049
3050 /* Now kill any processes that happen to have the tty open */
3051 for_each_process_thread(g, p) {
3052 if (p->signal->tty == tty) {
3053 tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n",
3054 task_pid_nr(p), p->comm);
3055 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
3056 PIDTYPE_SID);
3057 continue;
3058 }
3059 task_lock(p);
3060 i = iterate_fd(p->files, 0, this_tty, tty);
3061 if (i != 0) {
3062 tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n",
3063 task_pid_nr(p), p->comm, i - 1);
3064 group_send_sig_info(SIGKILL, SEND_SIG_PRIV, p,
3065 PIDTYPE_SID);
3066 }
3067 task_unlock(p);
3068 }
3069 read_unlock(&tasklist_lock);
3070 put_pid(session);
3071}
3072
3073static void do_SAK_work(struct work_struct *work)
3074{
3075 struct tty_struct *tty =
3076 container_of(work, struct tty_struct, SAK_work);
3077 __do_SAK(tty);
3078}
3079
3080/*
3081 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3082 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3083 * the values which we write to it will be identical to the values which it
3084 * already has. --akpm
3085 */
3086void do_SAK(struct tty_struct *tty)
3087{
3088 if (!tty)
3089 return;
3090 schedule_work(&tty->SAK_work);
3091}
3092EXPORT_SYMBOL(do_SAK);
3093
3094/* Must put_device() after it's unused! */
3095static struct device *tty_get_device(struct tty_struct *tty)
3096{
3097 dev_t devt = tty_devnum(tty);
3098
3099 return class_find_device_by_devt(&tty_class, devt);
3100}
3101
3102
3103/**
3104 * alloc_tty_struct - allocate a new tty
3105 * @driver: driver which will handle the returned tty
3106 * @idx: minor of the tty
3107 *
3108 * This subroutine allocates and initializes a tty structure.
3109 *
3110 * Locking: none - @tty in question is not exposed at this point
3111 */
3112struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
3113{
3114 struct tty_struct *tty;
3115
3116 tty = kzalloc(sizeof(*tty), GFP_KERNEL_ACCOUNT);
3117 if (!tty)
3118 return NULL;
3119
3120 kref_init(&tty->kref);
3121 if (tty_ldisc_init(tty)) {
3122 kfree(tty);
3123 return NULL;
3124 }
3125 tty->ctrl.session = NULL;
3126 tty->ctrl.pgrp = NULL;
3127 mutex_init(&tty->legacy_mutex);
3128 mutex_init(&tty->throttle_mutex);
3129 init_rwsem(&tty->termios_rwsem);
3130 mutex_init(&tty->winsize_mutex);
3131 init_ldsem(&tty->ldisc_sem);
3132 init_waitqueue_head(&tty->write_wait);
3133 init_waitqueue_head(&tty->read_wait);
3134 INIT_WORK(&tty->hangup_work, do_tty_hangup);
3135 mutex_init(&tty->atomic_write_lock);
3136 spin_lock_init(&tty->ctrl.lock);
3137 spin_lock_init(&tty->flow.lock);
3138 spin_lock_init(&tty->files_lock);
3139 INIT_LIST_HEAD(&tty->tty_files);
3140 INIT_WORK(&tty->SAK_work, do_SAK_work);
3141
3142 tty->driver = driver;
3143 tty->ops = driver->ops;
3144 tty->index = idx;
3145 tty_line_name(driver, idx, tty->name);
3146 tty->dev = tty_get_device(tty);
3147
3148 return tty;
3149}
3150
3151/**
3152 * tty_put_char - write one character to a tty
3153 * @tty: tty
3154 * @ch: character to write
3155 *
3156 * Write one byte to the @tty using the provided @tty->ops->put_char() method
3157 * if present.
3158 *
3159 * Note: the specific put_char operation in the driver layer may go
3160 * away soon. Don't call it directly, use this method
3161 *
3162 * Return: the number of characters successfully output.
3163 */
3164int tty_put_char(struct tty_struct *tty, u8 ch)
3165{
3166 if (tty->ops->put_char)
3167 return tty->ops->put_char(tty, ch);
3168 return tty->ops->write(tty, &ch, 1);
3169}
3170EXPORT_SYMBOL_GPL(tty_put_char);
3171
3172static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3173 unsigned int index, unsigned int count)
3174{
3175 int err;
3176
3177 /* init here, since reused cdevs cause crashes */
3178 driver->cdevs[index] = cdev_alloc();
3179 if (!driver->cdevs[index])
3180 return -ENOMEM;
3181 driver->cdevs[index]->ops = &tty_fops;
3182 driver->cdevs[index]->owner = driver->owner;
3183 err = cdev_add(driver->cdevs[index], dev, count);
3184 if (err)
3185 kobject_put(&driver->cdevs[index]->kobj);
3186 return err;
3187}
3188
3189/**
3190 * tty_register_device - register a tty device
3191 * @driver: the tty driver that describes the tty device
3192 * @index: the index in the tty driver for this tty device
3193 * @device: a struct device that is associated with this tty device.
3194 * This field is optional, if there is no known struct device
3195 * for this tty device it can be set to NULL safely.
3196 *
3197 * This call is required to be made to register an individual tty device
3198 * if the tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If
3199 * that bit is not set, this function should not be called by a tty
3200 * driver.
3201 *
3202 * Locking: ??
3203 *
3204 * Return: A pointer to the struct device for this tty device (or
3205 * ERR_PTR(-EFOO) on error).
3206 */
3207struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3208 struct device *device)
3209{
3210 return tty_register_device_attr(driver, index, device, NULL, NULL);
3211}
3212EXPORT_SYMBOL(tty_register_device);
3213
3214static void tty_device_create_release(struct device *dev)
3215{
3216 dev_dbg(dev, "releasing...\n");
3217 kfree(dev);
3218}
3219
3220/**
3221 * tty_register_device_attr - register a tty device
3222 * @driver: the tty driver that describes the tty device
3223 * @index: the index in the tty driver for this tty device
3224 * @device: a struct device that is associated with this tty device.
3225 * This field is optional, if there is no known struct device
3226 * for this tty device it can be set to %NULL safely.
3227 * @drvdata: Driver data to be set to device.
3228 * @attr_grp: Attribute group to be set on device.
3229 *
3230 * This call is required to be made to register an individual tty device if the
3231 * tty driver's flags have the %TTY_DRIVER_DYNAMIC_DEV bit set. If that bit is
3232 * not set, this function should not be called by a tty driver.
3233 *
3234 * Locking: ??
3235 *
3236 * Return: A pointer to the struct device for this tty device (or
3237 * ERR_PTR(-EFOO) on error).
3238 */
3239struct device *tty_register_device_attr(struct tty_driver *driver,
3240 unsigned index, struct device *device,
3241 void *drvdata,
3242 const struct attribute_group **attr_grp)
3243{
3244 char name[64];
3245 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3246 struct ktermios *tp;
3247 struct device *dev;
3248 int retval;
3249
3250 if (index >= driver->num) {
3251 pr_err("%s: Attempt to register invalid tty line number (%d)\n",
3252 driver->name, index);
3253 return ERR_PTR(-EINVAL);
3254 }
3255
3256 if (driver->type == TTY_DRIVER_TYPE_PTY)
3257 pty_line_name(driver, index, name);
3258 else
3259 tty_line_name(driver, index, name);
3260
3261 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3262 if (!dev)
3263 return ERR_PTR(-ENOMEM);
3264
3265 dev->devt = devt;
3266 dev->class = &tty_class;
3267 dev->parent = device;
3268 dev->release = tty_device_create_release;
3269 dev_set_name(dev, "%s", name);
3270 dev->groups = attr_grp;
3271 dev_set_drvdata(dev, drvdata);
3272
3273 dev_set_uevent_suppress(dev, 1);
3274
3275 retval = device_register(dev);
3276 if (retval)
3277 goto err_put;
3278
3279 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3280 /*
3281 * Free any saved termios data so that the termios state is
3282 * reset when reusing a minor number.
3283 */
3284 tp = driver->termios[index];
3285 if (tp) {
3286 driver->termios[index] = NULL;
3287 kfree(tp);
3288 }
3289
3290 retval = tty_cdev_add(driver, devt, index, 1);
3291 if (retval)
3292 goto err_del;
3293 }
3294
3295 dev_set_uevent_suppress(dev, 0);
3296 kobject_uevent(&dev->kobj, KOBJ_ADD);
3297
3298 return dev;
3299
3300err_del:
3301 device_del(dev);
3302err_put:
3303 put_device(dev);
3304
3305 return ERR_PTR(retval);
3306}
3307EXPORT_SYMBOL_GPL(tty_register_device_attr);
3308
3309/**
3310 * tty_unregister_device - unregister a tty device
3311 * @driver: the tty driver that describes the tty device
3312 * @index: the index in the tty driver for this tty device
3313 *
3314 * If a tty device is registered with a call to tty_register_device() then
3315 * this function must be called when the tty device is gone.
3316 *
3317 * Locking: ??
3318 */
3319void tty_unregister_device(struct tty_driver *driver, unsigned index)
3320{
3321 device_destroy(&tty_class, MKDEV(driver->major, driver->minor_start) + index);
3322 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3323 cdev_del(driver->cdevs[index]);
3324 driver->cdevs[index] = NULL;
3325 }
3326}
3327EXPORT_SYMBOL(tty_unregister_device);
3328
3329/**
3330 * __tty_alloc_driver - allocate tty driver
3331 * @lines: count of lines this driver can handle at most
3332 * @owner: module which is responsible for this driver
3333 * @flags: some of %TTY_DRIVER_ flags, will be set in driver->flags
3334 *
3335 * This should not be called directly, some of the provided macros should be
3336 * used instead. Use IS_ERR() and friends on @retval.
3337 */
3338struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3339 unsigned long flags)
3340{
3341 struct tty_driver *driver;
3342 unsigned int cdevs = 1;
3343 int err;
3344
3345 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3346 return ERR_PTR(-EINVAL);
3347
3348 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
3349 if (!driver)
3350 return ERR_PTR(-ENOMEM);
3351
3352 kref_init(&driver->kref);
3353 driver->num = lines;
3354 driver->owner = owner;
3355 driver->flags = flags;
3356
3357 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3358 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3359 GFP_KERNEL);
3360 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3361 GFP_KERNEL);
3362 if (!driver->ttys || !driver->termios) {
3363 err = -ENOMEM;
3364 goto err_free_all;
3365 }
3366 }
3367
3368 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3369 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3370 GFP_KERNEL);
3371 if (!driver->ports) {
3372 err = -ENOMEM;
3373 goto err_free_all;
3374 }
3375 cdevs = lines;
3376 }
3377
3378 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3379 if (!driver->cdevs) {
3380 err = -ENOMEM;
3381 goto err_free_all;
3382 }
3383
3384 return driver;
3385err_free_all:
3386 kfree(driver->ports);
3387 kfree(driver->ttys);
3388 kfree(driver->termios);
3389 kfree(driver->cdevs);
3390 kfree(driver);
3391 return ERR_PTR(err);
3392}
3393EXPORT_SYMBOL(__tty_alloc_driver);
3394
3395static void destruct_tty_driver(struct kref *kref)
3396{
3397 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3398 int i;
3399 struct ktermios *tp;
3400
3401 if (driver->flags & TTY_DRIVER_INSTALLED) {
3402 for (i = 0; i < driver->num; i++) {
3403 tp = driver->termios[i];
3404 if (tp) {
3405 driver->termios[i] = NULL;
3406 kfree(tp);
3407 }
3408 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3409 tty_unregister_device(driver, i);
3410 }
3411 proc_tty_unregister_driver(driver);
3412 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3413 cdev_del(driver->cdevs[0]);
3414 }
3415 kfree(driver->cdevs);
3416 kfree(driver->ports);
3417 kfree(driver->termios);
3418 kfree(driver->ttys);
3419 kfree(driver);
3420}
3421
3422/**
3423 * tty_driver_kref_put - drop a reference to a tty driver
3424 * @driver: driver of which to drop the reference
3425 *
3426 * The final put will destroy and free up the driver.
3427 */
3428void tty_driver_kref_put(struct tty_driver *driver)
3429{
3430 kref_put(&driver->kref, destruct_tty_driver);
3431}
3432EXPORT_SYMBOL(tty_driver_kref_put);
3433
3434/**
3435 * tty_register_driver - register a tty driver
3436 * @driver: driver to register
3437 *
3438 * Called by a tty driver to register itself.
3439 */
3440int tty_register_driver(struct tty_driver *driver)
3441{
3442 int error;
3443 int i;
3444 dev_t dev;
3445 struct device *d;
3446
3447 if (!driver->major) {
3448 error = alloc_chrdev_region(&dev, driver->minor_start,
3449 driver->num, driver->name);
3450 if (!error) {
3451 driver->major = MAJOR(dev);
3452 driver->minor_start = MINOR(dev);
3453 }
3454 } else {
3455 dev = MKDEV(driver->major, driver->minor_start);
3456 error = register_chrdev_region(dev, driver->num, driver->name);
3457 }
3458 if (error < 0)
3459 goto err;
3460
3461 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3462 error = tty_cdev_add(driver, dev, 0, driver->num);
3463 if (error)
3464 goto err_unreg_char;
3465 }
3466
3467 mutex_lock(&tty_mutex);
3468 list_add(&driver->tty_drivers, &tty_drivers);
3469 mutex_unlock(&tty_mutex);
3470
3471 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3472 for (i = 0; i < driver->num; i++) {
3473 d = tty_register_device(driver, i, NULL);
3474 if (IS_ERR(d)) {
3475 error = PTR_ERR(d);
3476 goto err_unreg_devs;
3477 }
3478 }
3479 }
3480 proc_tty_register_driver(driver);
3481 driver->flags |= TTY_DRIVER_INSTALLED;
3482 return 0;
3483
3484err_unreg_devs:
3485 for (i--; i >= 0; i--)
3486 tty_unregister_device(driver, i);
3487
3488 mutex_lock(&tty_mutex);
3489 list_del(&driver->tty_drivers);
3490 mutex_unlock(&tty_mutex);
3491
3492err_unreg_char:
3493 unregister_chrdev_region(dev, driver->num);
3494err:
3495 return error;
3496}
3497EXPORT_SYMBOL(tty_register_driver);
3498
3499/**
3500 * tty_unregister_driver - unregister a tty driver
3501 * @driver: driver to unregister
3502 *
3503 * Called by a tty driver to unregister itself.
3504 */
3505void tty_unregister_driver(struct tty_driver *driver)
3506{
3507 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3508 driver->num);
3509 mutex_lock(&tty_mutex);
3510 list_del(&driver->tty_drivers);
3511 mutex_unlock(&tty_mutex);
3512}
3513EXPORT_SYMBOL(tty_unregister_driver);
3514
3515dev_t tty_devnum(struct tty_struct *tty)
3516{
3517 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3518}
3519EXPORT_SYMBOL(tty_devnum);
3520
3521void tty_default_fops(struct file_operations *fops)
3522{
3523 *fops = tty_fops;
3524}
3525
3526static char *tty_devnode(const struct device *dev, umode_t *mode)
3527{
3528 if (!mode)
3529 return NULL;
3530 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3531 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3532 *mode = 0666;
3533 return NULL;
3534}
3535
3536const struct class tty_class = {
3537 .name = "tty",
3538 .devnode = tty_devnode,
3539};
3540
3541static int __init tty_class_init(void)
3542{
3543 return class_register(&tty_class);
3544}
3545
3546postcore_initcall(tty_class_init);
3547
3548/* 3/2004 jmc: why do these devices exist? */
3549static struct cdev tty_cdev, console_cdev;
3550
3551static ssize_t show_cons_active(struct device *dev,
3552 struct device_attribute *attr, char *buf)
3553{
3554 struct console *cs[16];
3555 int i = 0;
3556 struct console *c;
3557 ssize_t count = 0;
3558
3559 /*
3560 * Hold the console_list_lock to guarantee that no consoles are
3561 * unregistered until all console processing is complete.
3562 * This also allows safe traversal of the console list and
3563 * race-free reading of @flags.
3564 */
3565 console_list_lock();
3566
3567 for_each_console(c) {
3568 if (!c->device)
3569 continue;
3570 if (!c->write)
3571 continue;
3572 if ((c->flags & CON_ENABLED) == 0)
3573 continue;
3574 cs[i++] = c;
3575 if (i >= ARRAY_SIZE(cs))
3576 break;
3577 }
3578
3579 /*
3580 * Take console_lock to serialize device() callback with
3581 * other console operations. For example, fg_console is
3582 * modified under console_lock when switching vt.
3583 */
3584 console_lock();
3585 while (i--) {
3586 int index = cs[i]->index;
3587 struct tty_driver *drv = cs[i]->device(cs[i], &index);
3588
3589 /* don't resolve tty0 as some programs depend on it */
3590 if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR))
3591 count += tty_line_name(drv, index, buf + count);
3592 else
3593 count += sprintf(buf + count, "%s%d",
3594 cs[i]->name, cs[i]->index);
3595
3596 count += sprintf(buf + count, "%c", i ? ' ':'\n');
3597 }
3598 console_unlock();
3599
3600 console_list_unlock();
3601
3602 return count;
3603}
3604static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3605
3606static struct attribute *cons_dev_attrs[] = {
3607 &dev_attr_active.attr,
3608 NULL
3609};
3610
3611ATTRIBUTE_GROUPS(cons_dev);
3612
3613static struct device *consdev;
3614
3615void console_sysfs_notify(void)
3616{
3617 if (consdev)
3618 sysfs_notify(&consdev->kobj, NULL, "active");
3619}
3620
3621static struct ctl_table tty_table[] = {
3622 {
3623 .procname = "legacy_tiocsti",
3624 .data = &tty_legacy_tiocsti,
3625 .maxlen = sizeof(tty_legacy_tiocsti),
3626 .mode = 0644,
3627 .proc_handler = proc_dobool,
3628 },
3629 {
3630 .procname = "ldisc_autoload",
3631 .data = &tty_ldisc_autoload,
3632 .maxlen = sizeof(tty_ldisc_autoload),
3633 .mode = 0644,
3634 .proc_handler = proc_dointvec,
3635 .extra1 = SYSCTL_ZERO,
3636 .extra2 = SYSCTL_ONE,
3637 },
3638};
3639
3640/*
3641 * Ok, now we can initialize the rest of the tty devices and can count
3642 * on memory allocations, interrupts etc..
3643 */
3644int __init tty_init(void)
3645{
3646 register_sysctl_init("dev/tty", tty_table);
3647 cdev_init(&tty_cdev, &tty_fops);
3648 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3649 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3650 panic("Couldn't register /dev/tty driver\n");
3651 device_create(&tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3652
3653 cdev_init(&console_cdev, &console_fops);
3654 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3655 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3656 panic("Couldn't register /dev/console driver\n");
3657 consdev = device_create_with_groups(&tty_class, NULL,
3658 MKDEV(TTYAUX_MAJOR, 1), NULL,
3659 cons_dev_groups, "console");
3660 if (IS_ERR(consdev))
3661 consdev = NULL;
3662
3663#ifdef CONFIG_VT
3664 vty_init(&console_fops);
3665#endif
3666 return 0;
3667}