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