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