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