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