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