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