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