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-rw-r--r--drivers/tty/tty_io.c3263
1 files changed, 3263 insertions, 0 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
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1/*
2 * linux/drivers/char/tty_io.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7/*
8 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
9 * or rs-channels. It also implements echoing, cooked mode etc.
10 *
11 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
12 *
13 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
14 * tty_struct and tty_queue structures. Previously there was an array
15 * of 256 tty_struct's which was statically allocated, and the
16 * tty_queue structures were allocated at boot time. Both are now
17 * dynamically allocated only when the tty is open.
18 *
19 * Also restructured routines so that there is more of a separation
20 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
21 * the low-level tty routines (serial.c, pty.c, console.c). This
22 * makes for cleaner and more compact code. -TYT, 9/17/92
23 *
24 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
25 * which can be dynamically activated and de-activated by the line
26 * discipline handling modules (like SLIP).
27 *
28 * NOTE: pay no attention to the line discipline code (yet); its
29 * interface is still subject to change in this version...
30 * -- TYT, 1/31/92
31 *
32 * Added functionality to the OPOST tty handling. No delays, but all
33 * other bits should be there.
34 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
35 *
36 * Rewrote canonical mode and added more termios flags.
37 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
38 *
39 * Reorganized FASYNC support so mouse code can share it.
40 * -- ctm@ardi.com, 9Sep95
41 *
42 * New TIOCLINUX variants added.
43 * -- mj@k332.feld.cvut.cz, 19-Nov-95
44 *
45 * Restrict vt switching via ioctl()
46 * -- grif@cs.ucr.edu, 5-Dec-95
47 *
48 * Move console and virtual terminal code to more appropriate files,
49 * implement CONFIG_VT and generalize console device interface.
50 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
51 *
52 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
53 * -- Bill Hawes <whawes@star.net>, June 97
54 *
55 * Added devfs support.
56 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
57 *
58 * Added support for a Unix98-style ptmx device.
59 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
60 *
61 * Reduced memory usage for older ARM systems
62 * -- Russell King <rmk@arm.linux.org.uk>
63 *
64 * Move do_SAK() into process context. Less stack use in devfs functions.
65 * alloc_tty_struct() always uses kmalloc()
66 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 */
68
69#include <linux/types.h>
70#include <linux/major.h>
71#include <linux/errno.h>
72#include <linux/signal.h>
73#include <linux/fcntl.h>
74#include <linux/sched.h>
75#include <linux/interrupt.h>
76#include <linux/tty.h>
77#include <linux/tty_driver.h>
78#include <linux/tty_flip.h>
79#include <linux/devpts_fs.h>
80#include <linux/file.h>
81#include <linux/fdtable.h>
82#include <linux/console.h>
83#include <linux/timer.h>
84#include <linux/ctype.h>
85#include <linux/kd.h>
86#include <linux/mm.h>
87#include <linux/string.h>
88#include <linux/slab.h>
89#include <linux/poll.h>
90#include <linux/proc_fs.h>
91#include <linux/init.h>
92#include <linux/module.h>
93#include <linux/smp_lock.h>
94#include <linux/device.h>
95#include <linux/wait.h>
96#include <linux/bitops.h>
97#include <linux/delay.h>
98#include <linux/seq_file.h>
99#include <linux/serial.h>
100
101#include <linux/uaccess.h>
102#include <asm/system.h>
103
104#include <linux/kbd_kern.h>
105#include <linux/vt_kern.h>
106#include <linux/selection.h>
107
108#include <linux/kmod.h>
109#include <linux/nsproxy.h>
110
111#undef TTY_DEBUG_HANGUP
112
113#define TTY_PARANOIA_CHECK 1
114#define CHECK_TTY_COUNT 1
115
116struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
117 .c_iflag = ICRNL | IXON,
118 .c_oflag = OPOST | ONLCR,
119 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
120 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
121 ECHOCTL | ECHOKE | IEXTEN,
122 .c_cc = INIT_C_CC,
123 .c_ispeed = 38400,
124 .c_ospeed = 38400
125};
126
127EXPORT_SYMBOL(tty_std_termios);
128
129/* This list gets poked at by procfs and various bits of boot up code. This
130 could do with some rationalisation such as pulling the tty proc function
131 into this file */
132
133LIST_HEAD(tty_drivers); /* linked list of tty drivers */
134
135/* Mutex to protect creating and releasing a tty. This is shared with
136 vt.c for deeply disgusting hack reasons */
137DEFINE_MUTEX(tty_mutex);
138EXPORT_SYMBOL(tty_mutex);
139
140/* Spinlock to protect the tty->tty_files list */
141DEFINE_SPINLOCK(tty_files_lock);
142
143static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
144static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
145ssize_t redirected_tty_write(struct file *, const char __user *,
146 size_t, loff_t *);
147static unsigned int tty_poll(struct file *, poll_table *);
148static int tty_open(struct inode *, struct file *);
149long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
150#ifdef CONFIG_COMPAT
151static long tty_compat_ioctl(struct file *file, unsigned int cmd,
152 unsigned long arg);
153#else
154#define tty_compat_ioctl NULL
155#endif
156static int __tty_fasync(int fd, struct file *filp, int on);
157static int tty_fasync(int fd, struct file *filp, int on);
158static void release_tty(struct tty_struct *tty, int idx);
159static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
160static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
161
162/**
163 * alloc_tty_struct - allocate a tty object
164 *
165 * Return a new empty tty structure. The data fields have not
166 * been initialized in any way but has been zeroed
167 *
168 * Locking: none
169 */
170
171struct tty_struct *alloc_tty_struct(void)
172{
173 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
174}
175
176/**
177 * free_tty_struct - free a disused tty
178 * @tty: tty struct to free
179 *
180 * Free the write buffers, tty queue and tty memory itself.
181 *
182 * Locking: none. Must be called after tty is definitely unused
183 */
184
185void free_tty_struct(struct tty_struct *tty)
186{
187 if (tty->dev)
188 put_device(tty->dev);
189 kfree(tty->write_buf);
190 tty_buffer_free_all(tty);
191 kfree(tty);
192}
193
194static inline struct tty_struct *file_tty(struct file *file)
195{
196 return ((struct tty_file_private *)file->private_data)->tty;
197}
198
199/* Associate a new file with the tty structure */
200int tty_add_file(struct tty_struct *tty, struct file *file)
201{
202 struct tty_file_private *priv;
203
204 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
205 if (!priv)
206 return -ENOMEM;
207
208 priv->tty = tty;
209 priv->file = file;
210 file->private_data = priv;
211
212 spin_lock(&tty_files_lock);
213 list_add(&priv->list, &tty->tty_files);
214 spin_unlock(&tty_files_lock);
215
216 return 0;
217}
218
219/* Delete file from its tty */
220void tty_del_file(struct file *file)
221{
222 struct tty_file_private *priv = file->private_data;
223
224 spin_lock(&tty_files_lock);
225 list_del(&priv->list);
226 spin_unlock(&tty_files_lock);
227 file->private_data = NULL;
228 kfree(priv);
229}
230
231
232#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
233
234/**
235 * tty_name - return tty naming
236 * @tty: tty structure
237 * @buf: buffer for output
238 *
239 * Convert a tty structure into a name. The name reflects the kernel
240 * naming policy and if udev is in use may not reflect user space
241 *
242 * Locking: none
243 */
244
245char *tty_name(struct tty_struct *tty, char *buf)
246{
247 if (!tty) /* Hmm. NULL pointer. That's fun. */
248 strcpy(buf, "NULL tty");
249 else
250 strcpy(buf, tty->name);
251 return buf;
252}
253
254EXPORT_SYMBOL(tty_name);
255
256int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
257 const char *routine)
258{
259#ifdef TTY_PARANOIA_CHECK
260 if (!tty) {
261 printk(KERN_WARNING
262 "null TTY for (%d:%d) in %s\n",
263 imajor(inode), iminor(inode), routine);
264 return 1;
265 }
266 if (tty->magic != TTY_MAGIC) {
267 printk(KERN_WARNING
268 "bad magic number for tty struct (%d:%d) in %s\n",
269 imajor(inode), iminor(inode), routine);
270 return 1;
271 }
272#endif
273 return 0;
274}
275
276static int check_tty_count(struct tty_struct *tty, const char *routine)
277{
278#ifdef CHECK_TTY_COUNT
279 struct list_head *p;
280 int count = 0;
281
282 spin_lock(&tty_files_lock);
283 list_for_each(p, &tty->tty_files) {
284 count++;
285 }
286 spin_unlock(&tty_files_lock);
287 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
288 tty->driver->subtype == PTY_TYPE_SLAVE &&
289 tty->link && tty->link->count)
290 count++;
291 if (tty->count != count) {
292 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
293 "!= #fd's(%d) in %s\n",
294 tty->name, tty->count, count, routine);
295 return count;
296 }
297#endif
298 return 0;
299}
300
301/**
302 * get_tty_driver - find device of a tty
303 * @dev_t: device identifier
304 * @index: returns the index of the tty
305 *
306 * This routine returns a tty driver structure, given a device number
307 * and also passes back the index number.
308 *
309 * Locking: caller must hold tty_mutex
310 */
311
312static struct tty_driver *get_tty_driver(dev_t device, int *index)
313{
314 struct tty_driver *p;
315
316 list_for_each_entry(p, &tty_drivers, tty_drivers) {
317 dev_t base = MKDEV(p->major, p->minor_start);
318 if (device < base || device >= base + p->num)
319 continue;
320 *index = device - base;
321 return tty_driver_kref_get(p);
322 }
323 return NULL;
324}
325
326#ifdef CONFIG_CONSOLE_POLL
327
328/**
329 * tty_find_polling_driver - find device of a polled tty
330 * @name: name string to match
331 * @line: pointer to resulting tty line nr
332 *
333 * This routine returns a tty driver structure, given a name
334 * and the condition that the tty driver is capable of polled
335 * operation.
336 */
337struct tty_driver *tty_find_polling_driver(char *name, int *line)
338{
339 struct tty_driver *p, *res = NULL;
340 int tty_line = 0;
341 int len;
342 char *str, *stp;
343
344 for (str = name; *str; str++)
345 if ((*str >= '0' && *str <= '9') || *str == ',')
346 break;
347 if (!*str)
348 return NULL;
349
350 len = str - name;
351 tty_line = simple_strtoul(str, &str, 10);
352
353 mutex_lock(&tty_mutex);
354 /* Search through the tty devices to look for a match */
355 list_for_each_entry(p, &tty_drivers, tty_drivers) {
356 if (strncmp(name, p->name, len) != 0)
357 continue;
358 stp = str;
359 if (*stp == ',')
360 stp++;
361 if (*stp == '\0')
362 stp = NULL;
363
364 if (tty_line >= 0 && tty_line < p->num && p->ops &&
365 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
366 res = tty_driver_kref_get(p);
367 *line = tty_line;
368 break;
369 }
370 }
371 mutex_unlock(&tty_mutex);
372
373 return res;
374}
375EXPORT_SYMBOL_GPL(tty_find_polling_driver);
376#endif
377
378/**
379 * tty_check_change - check for POSIX terminal changes
380 * @tty: tty to check
381 *
382 * If we try to write to, or set the state of, a terminal and we're
383 * not in the foreground, send a SIGTTOU. If the signal is blocked or
384 * ignored, go ahead and perform the operation. (POSIX 7.2)
385 *
386 * Locking: ctrl_lock
387 */
388
389int tty_check_change(struct tty_struct *tty)
390{
391 unsigned long flags;
392 int ret = 0;
393
394 if (current->signal->tty != tty)
395 return 0;
396
397 spin_lock_irqsave(&tty->ctrl_lock, flags);
398
399 if (!tty->pgrp) {
400 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
401 goto out_unlock;
402 }
403 if (task_pgrp(current) == tty->pgrp)
404 goto out_unlock;
405 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
406 if (is_ignored(SIGTTOU))
407 goto out;
408 if (is_current_pgrp_orphaned()) {
409 ret = -EIO;
410 goto out;
411 }
412 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
413 set_thread_flag(TIF_SIGPENDING);
414 ret = -ERESTARTSYS;
415out:
416 return ret;
417out_unlock:
418 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
419 return ret;
420}
421
422EXPORT_SYMBOL(tty_check_change);
423
424static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
425 size_t count, loff_t *ppos)
426{
427 return 0;
428}
429
430static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
431 size_t count, loff_t *ppos)
432{
433 return -EIO;
434}
435
436/* No kernel lock held - none needed ;) */
437static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
438{
439 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
440}
441
442static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
443 unsigned long arg)
444{
445 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
446}
447
448static long hung_up_tty_compat_ioctl(struct file *file,
449 unsigned int cmd, unsigned long arg)
450{
451 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
452}
453
454static const struct file_operations tty_fops = {
455 .llseek = no_llseek,
456 .read = tty_read,
457 .write = tty_write,
458 .poll = tty_poll,
459 .unlocked_ioctl = tty_ioctl,
460 .compat_ioctl = tty_compat_ioctl,
461 .open = tty_open,
462 .release = tty_release,
463 .fasync = tty_fasync,
464};
465
466static const struct file_operations console_fops = {
467 .llseek = no_llseek,
468 .read = tty_read,
469 .write = redirected_tty_write,
470 .poll = tty_poll,
471 .unlocked_ioctl = tty_ioctl,
472 .compat_ioctl = tty_compat_ioctl,
473 .open = tty_open,
474 .release = tty_release,
475 .fasync = tty_fasync,
476};
477
478static const struct file_operations hung_up_tty_fops = {
479 .llseek = no_llseek,
480 .read = hung_up_tty_read,
481 .write = hung_up_tty_write,
482 .poll = hung_up_tty_poll,
483 .unlocked_ioctl = hung_up_tty_ioctl,
484 .compat_ioctl = hung_up_tty_compat_ioctl,
485 .release = tty_release,
486};
487
488static DEFINE_SPINLOCK(redirect_lock);
489static struct file *redirect;
490
491/**
492 * tty_wakeup - request more data
493 * @tty: terminal
494 *
495 * Internal and external helper for wakeups of tty. This function
496 * informs the line discipline if present that the driver is ready
497 * to receive more output data.
498 */
499
500void tty_wakeup(struct tty_struct *tty)
501{
502 struct tty_ldisc *ld;
503
504 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
505 ld = tty_ldisc_ref(tty);
506 if (ld) {
507 if (ld->ops->write_wakeup)
508 ld->ops->write_wakeup(tty);
509 tty_ldisc_deref(ld);
510 }
511 }
512 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
513}
514
515EXPORT_SYMBOL_GPL(tty_wakeup);
516
517/**
518 * __tty_hangup - actual handler for hangup events
519 * @work: tty device
520 *
521 * This can be called by the "eventd" kernel thread. That is process
522 * synchronous but doesn't hold any locks, so we need to make sure we
523 * have the appropriate locks for what we're doing.
524 *
525 * The hangup event clears any pending redirections onto the hung up
526 * device. It ensures future writes will error and it does the needed
527 * line discipline hangup and signal delivery. The tty object itself
528 * remains intact.
529 *
530 * Locking:
531 * BTM
532 * redirect lock for undoing redirection
533 * file list lock for manipulating list of ttys
534 * tty_ldisc_lock from called functions
535 * termios_mutex resetting termios data
536 * tasklist_lock to walk task list for hangup event
537 * ->siglock to protect ->signal/->sighand
538 */
539void __tty_hangup(struct tty_struct *tty)
540{
541 struct file *cons_filp = NULL;
542 struct file *filp, *f = NULL;
543 struct task_struct *p;
544 struct tty_file_private *priv;
545 int closecount = 0, n;
546 unsigned long flags;
547 int refs = 0;
548
549 if (!tty)
550 return;
551
552
553 spin_lock(&redirect_lock);
554 if (redirect && file_tty(redirect) == tty) {
555 f = redirect;
556 redirect = NULL;
557 }
558 spin_unlock(&redirect_lock);
559
560 tty_lock();
561
562 /* inuse_filps is protected by the single tty lock,
563 this really needs to change if we want to flush the
564 workqueue with the lock held */
565 check_tty_count(tty, "tty_hangup");
566
567 spin_lock(&tty_files_lock);
568 /* This breaks for file handles being sent over AF_UNIX sockets ? */
569 list_for_each_entry(priv, &tty->tty_files, list) {
570 filp = priv->file;
571 if (filp->f_op->write == redirected_tty_write)
572 cons_filp = filp;
573 if (filp->f_op->write != tty_write)
574 continue;
575 closecount++;
576 __tty_fasync(-1, filp, 0); /* can't block */
577 filp->f_op = &hung_up_tty_fops;
578 }
579 spin_unlock(&tty_files_lock);
580
581 tty_ldisc_hangup(tty);
582
583 read_lock(&tasklist_lock);
584 if (tty->session) {
585 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
586 spin_lock_irq(&p->sighand->siglock);
587 if (p->signal->tty == tty) {
588 p->signal->tty = NULL;
589 /* We defer the dereferences outside fo
590 the tasklist lock */
591 refs++;
592 }
593 if (!p->signal->leader) {
594 spin_unlock_irq(&p->sighand->siglock);
595 continue;
596 }
597 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
598 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
599 put_pid(p->signal->tty_old_pgrp); /* A noop */
600 spin_lock_irqsave(&tty->ctrl_lock, flags);
601 if (tty->pgrp)
602 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
603 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
604 spin_unlock_irq(&p->sighand->siglock);
605 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
606 }
607 read_unlock(&tasklist_lock);
608
609 spin_lock_irqsave(&tty->ctrl_lock, flags);
610 clear_bit(TTY_THROTTLED, &tty->flags);
611 clear_bit(TTY_PUSH, &tty->flags);
612 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
613 put_pid(tty->session);
614 put_pid(tty->pgrp);
615 tty->session = NULL;
616 tty->pgrp = NULL;
617 tty->ctrl_status = 0;
618 set_bit(TTY_HUPPED, &tty->flags);
619 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
620
621 /* Account for the p->signal references we killed */
622 while (refs--)
623 tty_kref_put(tty);
624
625 /*
626 * If one of the devices matches a console pointer, we
627 * cannot just call hangup() because that will cause
628 * tty->count and state->count to go out of sync.
629 * So we just call close() the right number of times.
630 */
631 if (cons_filp) {
632 if (tty->ops->close)
633 for (n = 0; n < closecount; n++)
634 tty->ops->close(tty, cons_filp);
635 } else if (tty->ops->hangup)
636 (tty->ops->hangup)(tty);
637 /*
638 * We don't want to have driver/ldisc interactions beyond
639 * the ones we did here. The driver layer expects no
640 * calls after ->hangup() from the ldisc side. However we
641 * can't yet guarantee all that.
642 */
643 set_bit(TTY_HUPPED, &tty->flags);
644 tty_ldisc_enable(tty);
645
646 tty_unlock();
647
648 if (f)
649 fput(f);
650}
651
652static void do_tty_hangup(struct work_struct *work)
653{
654 struct tty_struct *tty =
655 container_of(work, struct tty_struct, hangup_work);
656
657 __tty_hangup(tty);
658}
659
660/**
661 * tty_hangup - trigger a hangup event
662 * @tty: tty to hangup
663 *
664 * A carrier loss (virtual or otherwise) has occurred on this like
665 * schedule a hangup sequence to run after this event.
666 */
667
668void tty_hangup(struct tty_struct *tty)
669{
670#ifdef TTY_DEBUG_HANGUP
671 char buf[64];
672 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
673#endif
674 schedule_work(&tty->hangup_work);
675}
676
677EXPORT_SYMBOL(tty_hangup);
678
679/**
680 * tty_vhangup - process vhangup
681 * @tty: tty to hangup
682 *
683 * The user has asked via system call for the terminal to be hung up.
684 * We do this synchronously so that when the syscall returns the process
685 * is complete. That guarantee is necessary for security reasons.
686 */
687
688void tty_vhangup(struct tty_struct *tty)
689{
690#ifdef TTY_DEBUG_HANGUP
691 char buf[64];
692
693 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
694#endif
695 __tty_hangup(tty);
696}
697
698EXPORT_SYMBOL(tty_vhangup);
699
700
701/**
702 * tty_vhangup_self - process vhangup for own ctty
703 *
704 * Perform a vhangup on the current controlling tty
705 */
706
707void tty_vhangup_self(void)
708{
709 struct tty_struct *tty;
710
711 tty = get_current_tty();
712 if (tty) {
713 tty_vhangup(tty);
714 tty_kref_put(tty);
715 }
716}
717
718/**
719 * tty_hung_up_p - was tty hung up
720 * @filp: file pointer of tty
721 *
722 * Return true if the tty has been subject to a vhangup or a carrier
723 * loss
724 */
725
726int tty_hung_up_p(struct file *filp)
727{
728 return (filp->f_op == &hung_up_tty_fops);
729}
730
731EXPORT_SYMBOL(tty_hung_up_p);
732
733static void session_clear_tty(struct pid *session)
734{
735 struct task_struct *p;
736 do_each_pid_task(session, PIDTYPE_SID, p) {
737 proc_clear_tty(p);
738 } while_each_pid_task(session, PIDTYPE_SID, p);
739}
740
741/**
742 * disassociate_ctty - disconnect controlling tty
743 * @on_exit: true if exiting so need to "hang up" the session
744 *
745 * This function is typically called only by the session leader, when
746 * it wants to disassociate itself from its controlling tty.
747 *
748 * It performs the following functions:
749 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
750 * (2) Clears the tty from being controlling the session
751 * (3) Clears the controlling tty for all processes in the
752 * session group.
753 *
754 * The argument on_exit is set to 1 if called when a process is
755 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
756 *
757 * Locking:
758 * BTM is taken for hysterical raisins, and held when
759 * called from no_tty().
760 * tty_mutex is taken to protect tty
761 * ->siglock is taken to protect ->signal/->sighand
762 * tasklist_lock is taken to walk process list for sessions
763 * ->siglock is taken to protect ->signal/->sighand
764 */
765
766void disassociate_ctty(int on_exit)
767{
768 struct tty_struct *tty;
769 struct pid *tty_pgrp = NULL;
770
771 if (!current->signal->leader)
772 return;
773
774 tty = get_current_tty();
775 if (tty) {
776 tty_pgrp = get_pid(tty->pgrp);
777 if (on_exit) {
778 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
779 tty_vhangup(tty);
780 }
781 tty_kref_put(tty);
782 } else if (on_exit) {
783 struct pid *old_pgrp;
784 spin_lock_irq(&current->sighand->siglock);
785 old_pgrp = current->signal->tty_old_pgrp;
786 current->signal->tty_old_pgrp = NULL;
787 spin_unlock_irq(&current->sighand->siglock);
788 if (old_pgrp) {
789 kill_pgrp(old_pgrp, SIGHUP, on_exit);
790 kill_pgrp(old_pgrp, SIGCONT, on_exit);
791 put_pid(old_pgrp);
792 }
793 return;
794 }
795 if (tty_pgrp) {
796 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
797 if (!on_exit)
798 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
799 put_pid(tty_pgrp);
800 }
801
802 spin_lock_irq(&current->sighand->siglock);
803 put_pid(current->signal->tty_old_pgrp);
804 current->signal->tty_old_pgrp = NULL;
805 spin_unlock_irq(&current->sighand->siglock);
806
807 tty = get_current_tty();
808 if (tty) {
809 unsigned long flags;
810 spin_lock_irqsave(&tty->ctrl_lock, flags);
811 put_pid(tty->session);
812 put_pid(tty->pgrp);
813 tty->session = NULL;
814 tty->pgrp = NULL;
815 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
816 tty_kref_put(tty);
817 } else {
818#ifdef TTY_DEBUG_HANGUP
819 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
820 " = NULL", tty);
821#endif
822 }
823
824 /* Now clear signal->tty under the lock */
825 read_lock(&tasklist_lock);
826 session_clear_tty(task_session(current));
827 read_unlock(&tasklist_lock);
828}
829
830/**
831 *
832 * no_tty - Ensure the current process does not have a controlling tty
833 */
834void no_tty(void)
835{
836 struct task_struct *tsk = current;
837 tty_lock();
838 disassociate_ctty(0);
839 tty_unlock();
840 proc_clear_tty(tsk);
841}
842
843
844/**
845 * stop_tty - propagate flow control
846 * @tty: tty to stop
847 *
848 * Perform flow control to the driver. For PTY/TTY pairs we
849 * must also propagate the TIOCKPKT status. May be called
850 * on an already stopped device and will not re-call the driver
851 * method.
852 *
853 * This functionality is used by both the line disciplines for
854 * halting incoming flow and by the driver. It may therefore be
855 * called from any context, may be under the tty atomic_write_lock
856 * but not always.
857 *
858 * Locking:
859 * Uses the tty control lock internally
860 */
861
862void stop_tty(struct tty_struct *tty)
863{
864 unsigned long flags;
865 spin_lock_irqsave(&tty->ctrl_lock, flags);
866 if (tty->stopped) {
867 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
868 return;
869 }
870 tty->stopped = 1;
871 if (tty->link && tty->link->packet) {
872 tty->ctrl_status &= ~TIOCPKT_START;
873 tty->ctrl_status |= TIOCPKT_STOP;
874 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
875 }
876 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
877 if (tty->ops->stop)
878 (tty->ops->stop)(tty);
879}
880
881EXPORT_SYMBOL(stop_tty);
882
883/**
884 * start_tty - propagate flow control
885 * @tty: tty to start
886 *
887 * Start a tty that has been stopped if at all possible. Perform
888 * any necessary wakeups and propagate the TIOCPKT status. If this
889 * is the tty was previous stopped and is being started then the
890 * driver start method is invoked and the line discipline woken.
891 *
892 * Locking:
893 * ctrl_lock
894 */
895
896void start_tty(struct tty_struct *tty)
897{
898 unsigned long flags;
899 spin_lock_irqsave(&tty->ctrl_lock, flags);
900 if (!tty->stopped || tty->flow_stopped) {
901 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
902 return;
903 }
904 tty->stopped = 0;
905 if (tty->link && tty->link->packet) {
906 tty->ctrl_status &= ~TIOCPKT_STOP;
907 tty->ctrl_status |= TIOCPKT_START;
908 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
909 }
910 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
911 if (tty->ops->start)
912 (tty->ops->start)(tty);
913 /* If we have a running line discipline it may need kicking */
914 tty_wakeup(tty);
915}
916
917EXPORT_SYMBOL(start_tty);
918
919/**
920 * tty_read - read method for tty device files
921 * @file: pointer to tty file
922 * @buf: user buffer
923 * @count: size of user buffer
924 * @ppos: unused
925 *
926 * Perform the read system call function on this terminal device. Checks
927 * for hung up devices before calling the line discipline method.
928 *
929 * Locking:
930 * Locks the line discipline internally while needed. Multiple
931 * read calls may be outstanding in parallel.
932 */
933
934static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
935 loff_t *ppos)
936{
937 int i;
938 struct inode *inode = file->f_path.dentry->d_inode;
939 struct tty_struct *tty = file_tty(file);
940 struct tty_ldisc *ld;
941
942 if (tty_paranoia_check(tty, inode, "tty_read"))
943 return -EIO;
944 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
945 return -EIO;
946
947 /* We want to wait for the line discipline to sort out in this
948 situation */
949 ld = tty_ldisc_ref_wait(tty);
950 if (ld->ops->read)
951 i = (ld->ops->read)(tty, file, buf, count);
952 else
953 i = -EIO;
954 tty_ldisc_deref(ld);
955 if (i > 0)
956 inode->i_atime = current_fs_time(inode->i_sb);
957 return i;
958}
959
960void tty_write_unlock(struct tty_struct *tty)
961{
962 mutex_unlock(&tty->atomic_write_lock);
963 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
964}
965
966int tty_write_lock(struct tty_struct *tty, int ndelay)
967{
968 if (!mutex_trylock(&tty->atomic_write_lock)) {
969 if (ndelay)
970 return -EAGAIN;
971 if (mutex_lock_interruptible(&tty->atomic_write_lock))
972 return -ERESTARTSYS;
973 }
974 return 0;
975}
976
977/*
978 * Split writes up in sane blocksizes to avoid
979 * denial-of-service type attacks
980 */
981static inline ssize_t do_tty_write(
982 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
983 struct tty_struct *tty,
984 struct file *file,
985 const char __user *buf,
986 size_t count)
987{
988 ssize_t ret, written = 0;
989 unsigned int chunk;
990
991 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
992 if (ret < 0)
993 return ret;
994
995 /*
996 * We chunk up writes into a temporary buffer. This
997 * simplifies low-level drivers immensely, since they
998 * don't have locking issues and user mode accesses.
999 *
1000 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1001 * big chunk-size..
1002 *
1003 * The default chunk-size is 2kB, because the NTTY
1004 * layer has problems with bigger chunks. It will
1005 * claim to be able to handle more characters than
1006 * it actually does.
1007 *
1008 * FIXME: This can probably go away now except that 64K chunks
1009 * are too likely to fail unless switched to vmalloc...
1010 */
1011 chunk = 2048;
1012 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1013 chunk = 65536;
1014 if (count < chunk)
1015 chunk = count;
1016
1017 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1018 if (tty->write_cnt < chunk) {
1019 unsigned char *buf_chunk;
1020
1021 if (chunk < 1024)
1022 chunk = 1024;
1023
1024 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1025 if (!buf_chunk) {
1026 ret = -ENOMEM;
1027 goto out;
1028 }
1029 kfree(tty->write_buf);
1030 tty->write_cnt = chunk;
1031 tty->write_buf = buf_chunk;
1032 }
1033
1034 /* Do the write .. */
1035 for (;;) {
1036 size_t size = count;
1037 if (size > chunk)
1038 size = chunk;
1039 ret = -EFAULT;
1040 if (copy_from_user(tty->write_buf, buf, size))
1041 break;
1042 ret = write(tty, file, tty->write_buf, size);
1043 if (ret <= 0)
1044 break;
1045 written += ret;
1046 buf += ret;
1047 count -= ret;
1048 if (!count)
1049 break;
1050 ret = -ERESTARTSYS;
1051 if (signal_pending(current))
1052 break;
1053 cond_resched();
1054 }
1055 if (written) {
1056 struct inode *inode = file->f_path.dentry->d_inode;
1057 inode->i_mtime = current_fs_time(inode->i_sb);
1058 ret = written;
1059 }
1060out:
1061 tty_write_unlock(tty);
1062 return ret;
1063}
1064
1065/**
1066 * tty_write_message - write a message to a certain tty, not just the console.
1067 * @tty: the destination tty_struct
1068 * @msg: the message to write
1069 *
1070 * This is used for messages that need to be redirected to a specific tty.
1071 * We don't put it into the syslog queue right now maybe in the future if
1072 * really needed.
1073 *
1074 * We must still hold the BTM and test the CLOSING flag for the moment.
1075 */
1076
1077void tty_write_message(struct tty_struct *tty, char *msg)
1078{
1079 if (tty) {
1080 mutex_lock(&tty->atomic_write_lock);
1081 tty_lock();
1082 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1083 tty_unlock();
1084 tty->ops->write(tty, msg, strlen(msg));
1085 } else
1086 tty_unlock();
1087 tty_write_unlock(tty);
1088 }
1089 return;
1090}
1091
1092
1093/**
1094 * tty_write - write method for tty device file
1095 * @file: tty file pointer
1096 * @buf: user data to write
1097 * @count: bytes to write
1098 * @ppos: unused
1099 *
1100 * Write data to a tty device via the line discipline.
1101 *
1102 * Locking:
1103 * Locks the line discipline as required
1104 * Writes to the tty driver are serialized by the atomic_write_lock
1105 * and are then processed in chunks to the device. The line discipline
1106 * write method will not be invoked in parallel for each device.
1107 */
1108
1109static ssize_t tty_write(struct file *file, const char __user *buf,
1110 size_t count, loff_t *ppos)
1111{
1112 struct inode *inode = file->f_path.dentry->d_inode;
1113 struct tty_struct *tty = file_tty(file);
1114 struct tty_ldisc *ld;
1115 ssize_t ret;
1116
1117 if (tty_paranoia_check(tty, inode, "tty_write"))
1118 return -EIO;
1119 if (!tty || !tty->ops->write ||
1120 (test_bit(TTY_IO_ERROR, &tty->flags)))
1121 return -EIO;
1122 /* Short term debug to catch buggy drivers */
1123 if (tty->ops->write_room == NULL)
1124 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1125 tty->driver->name);
1126 ld = tty_ldisc_ref_wait(tty);
1127 if (!ld->ops->write)
1128 ret = -EIO;
1129 else
1130 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1131 tty_ldisc_deref(ld);
1132 return ret;
1133}
1134
1135ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1136 size_t count, loff_t *ppos)
1137{
1138 struct file *p = NULL;
1139
1140 spin_lock(&redirect_lock);
1141 if (redirect) {
1142 get_file(redirect);
1143 p = redirect;
1144 }
1145 spin_unlock(&redirect_lock);
1146
1147 if (p) {
1148 ssize_t res;
1149 res = vfs_write(p, buf, count, &p->f_pos);
1150 fput(p);
1151 return res;
1152 }
1153 return tty_write(file, buf, count, ppos);
1154}
1155
1156static char ptychar[] = "pqrstuvwxyzabcde";
1157
1158/**
1159 * pty_line_name - generate name for a pty
1160 * @driver: the tty driver in use
1161 * @index: the minor number
1162 * @p: output buffer of at least 6 bytes
1163 *
1164 * Generate a name from a driver reference and write it to the output
1165 * buffer.
1166 *
1167 * Locking: None
1168 */
1169static void pty_line_name(struct tty_driver *driver, int index, char *p)
1170{
1171 int i = index + driver->name_base;
1172 /* ->name is initialized to "ttyp", but "tty" is expected */
1173 sprintf(p, "%s%c%x",
1174 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1175 ptychar[i >> 4 & 0xf], i & 0xf);
1176}
1177
1178/**
1179 * tty_line_name - generate name for a tty
1180 * @driver: the tty driver in use
1181 * @index: the minor number
1182 * @p: output buffer of at least 7 bytes
1183 *
1184 * Generate a name from a driver reference and write it to the output
1185 * buffer.
1186 *
1187 * Locking: None
1188 */
1189static void tty_line_name(struct tty_driver *driver, int index, char *p)
1190{
1191 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1192}
1193
1194/**
1195 * tty_driver_lookup_tty() - find an existing tty, if any
1196 * @driver: the driver for the tty
1197 * @idx: the minor number
1198 *
1199 * Return the tty, if found or ERR_PTR() otherwise.
1200 *
1201 * Locking: tty_mutex must be held. If tty is found, the mutex must
1202 * be held until the 'fast-open' is also done. Will change once we
1203 * have refcounting in the driver and per driver locking
1204 */
1205static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1206 struct inode *inode, int idx)
1207{
1208 struct tty_struct *tty;
1209
1210 if (driver->ops->lookup)
1211 return driver->ops->lookup(driver, inode, idx);
1212
1213 tty = driver->ttys[idx];
1214 return tty;
1215}
1216
1217/**
1218 * tty_init_termios - helper for termios setup
1219 * @tty: the tty to set up
1220 *
1221 * Initialise the termios structures for this tty. Thus runs under
1222 * the tty_mutex currently so we can be relaxed about ordering.
1223 */
1224
1225int tty_init_termios(struct tty_struct *tty)
1226{
1227 struct ktermios *tp;
1228 int idx = tty->index;
1229
1230 tp = tty->driver->termios[idx];
1231 if (tp == NULL) {
1232 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1233 if (tp == NULL)
1234 return -ENOMEM;
1235 memcpy(tp, &tty->driver->init_termios,
1236 sizeof(struct ktermios));
1237 tty->driver->termios[idx] = tp;
1238 }
1239 tty->termios = tp;
1240 tty->termios_locked = tp + 1;
1241
1242 /* Compatibility until drivers always set this */
1243 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1244 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1245 return 0;
1246}
1247EXPORT_SYMBOL_GPL(tty_init_termios);
1248
1249/**
1250 * tty_driver_install_tty() - install a tty entry in the driver
1251 * @driver: the driver for the tty
1252 * @tty: the tty
1253 *
1254 * Install a tty object into the driver tables. The tty->index field
1255 * will be set by the time this is called. This method is responsible
1256 * for ensuring any need additional structures are allocated and
1257 * configured.
1258 *
1259 * Locking: tty_mutex for now
1260 */
1261static int tty_driver_install_tty(struct tty_driver *driver,
1262 struct tty_struct *tty)
1263{
1264 int idx = tty->index;
1265 int ret;
1266
1267 if (driver->ops->install) {
1268 ret = driver->ops->install(driver, tty);
1269 return ret;
1270 }
1271
1272 if (tty_init_termios(tty) == 0) {
1273 tty_driver_kref_get(driver);
1274 tty->count++;
1275 driver->ttys[idx] = tty;
1276 return 0;
1277 }
1278 return -ENOMEM;
1279}
1280
1281/**
1282 * tty_driver_remove_tty() - remove a tty from the driver tables
1283 * @driver: the driver for the tty
1284 * @idx: the minor number
1285 *
1286 * Remvoe a tty object from the driver tables. The tty->index field
1287 * will be set by the time this is called.
1288 *
1289 * Locking: tty_mutex for now
1290 */
1291static void tty_driver_remove_tty(struct tty_driver *driver,
1292 struct tty_struct *tty)
1293{
1294 if (driver->ops->remove)
1295 driver->ops->remove(driver, tty);
1296 else
1297 driver->ttys[tty->index] = NULL;
1298}
1299
1300/*
1301 * tty_reopen() - fast re-open of an open tty
1302 * @tty - the tty to open
1303 *
1304 * Return 0 on success, -errno on error.
1305 *
1306 * Locking: tty_mutex must be held from the time the tty was found
1307 * till this open completes.
1308 */
1309static int tty_reopen(struct tty_struct *tty)
1310{
1311 struct tty_driver *driver = tty->driver;
1312
1313 if (test_bit(TTY_CLOSING, &tty->flags))
1314 return -EIO;
1315
1316 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1317 driver->subtype == PTY_TYPE_MASTER) {
1318 /*
1319 * special case for PTY masters: only one open permitted,
1320 * and the slave side open count is incremented as well.
1321 */
1322 if (tty->count)
1323 return -EIO;
1324
1325 tty->link->count++;
1326 }
1327 tty->count++;
1328 tty->driver = driver; /* N.B. why do this every time?? */
1329
1330 mutex_lock(&tty->ldisc_mutex);
1331 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1332 mutex_unlock(&tty->ldisc_mutex);
1333
1334 return 0;
1335}
1336
1337/**
1338 * tty_init_dev - initialise a tty device
1339 * @driver: tty driver we are opening a device on
1340 * @idx: device index
1341 * @ret_tty: returned tty structure
1342 * @first_ok: ok to open a new device (used by ptmx)
1343 *
1344 * Prepare a tty device. This may not be a "new" clean device but
1345 * could also be an active device. The pty drivers require special
1346 * handling because of this.
1347 *
1348 * Locking:
1349 * The function is called under the tty_mutex, which
1350 * protects us from the tty struct or driver itself going away.
1351 *
1352 * On exit the tty device has the line discipline attached and
1353 * a reference count of 1. If a pair was created for pty/tty use
1354 * and the other was a pty master then it too has a reference count of 1.
1355 *
1356 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1357 * failed open. The new code protects the open with a mutex, so it's
1358 * really quite straightforward. The mutex locking can probably be
1359 * relaxed for the (most common) case of reopening a tty.
1360 */
1361
1362struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1363 int first_ok)
1364{
1365 struct tty_struct *tty;
1366 int retval;
1367
1368 /* Check if pty master is being opened multiple times */
1369 if (driver->subtype == PTY_TYPE_MASTER &&
1370 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1371 return ERR_PTR(-EIO);
1372 }
1373
1374 /*
1375 * First time open is complex, especially for PTY devices.
1376 * This code guarantees that either everything succeeds and the
1377 * TTY is ready for operation, or else the table slots are vacated
1378 * and the allocated memory released. (Except that the termios
1379 * and locked termios may be retained.)
1380 */
1381
1382 if (!try_module_get(driver->owner))
1383 return ERR_PTR(-ENODEV);
1384
1385 tty = alloc_tty_struct();
1386 if (!tty)
1387 goto fail_no_mem;
1388 initialize_tty_struct(tty, driver, idx);
1389
1390 retval = tty_driver_install_tty(driver, tty);
1391 if (retval < 0) {
1392 free_tty_struct(tty);
1393 module_put(driver->owner);
1394 return ERR_PTR(retval);
1395 }
1396
1397 /*
1398 * Structures all installed ... call the ldisc open routines.
1399 * If we fail here just call release_tty to clean up. No need
1400 * to decrement the use counts, as release_tty doesn't care.
1401 */
1402 retval = tty_ldisc_setup(tty, tty->link);
1403 if (retval)
1404 goto release_mem_out;
1405 return tty;
1406
1407fail_no_mem:
1408 module_put(driver->owner);
1409 return ERR_PTR(-ENOMEM);
1410
1411 /* call the tty release_tty routine to clean out this slot */
1412release_mem_out:
1413 if (printk_ratelimit())
1414 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1415 "clearing slot %d\n", idx);
1416 release_tty(tty, idx);
1417 return ERR_PTR(retval);
1418}
1419
1420void tty_free_termios(struct tty_struct *tty)
1421{
1422 struct ktermios *tp;
1423 int idx = tty->index;
1424 /* Kill this flag and push into drivers for locking etc */
1425 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1426 /* FIXME: Locking on ->termios array */
1427 tp = tty->termios;
1428 tty->driver->termios[idx] = NULL;
1429 kfree(tp);
1430 }
1431}
1432EXPORT_SYMBOL(tty_free_termios);
1433
1434void tty_shutdown(struct tty_struct *tty)
1435{
1436 tty_driver_remove_tty(tty->driver, tty);
1437 tty_free_termios(tty);
1438}
1439EXPORT_SYMBOL(tty_shutdown);
1440
1441/**
1442 * release_one_tty - release tty structure memory
1443 * @kref: kref of tty we are obliterating
1444 *
1445 * Releases memory associated with a tty structure, and clears out the
1446 * driver table slots. This function is called when a device is no longer
1447 * in use. It also gets called when setup of a device fails.
1448 *
1449 * Locking:
1450 * tty_mutex - sometimes only
1451 * takes the file list lock internally when working on the list
1452 * of ttys that the driver keeps.
1453 *
1454 * This method gets called from a work queue so that the driver private
1455 * cleanup ops can sleep (needed for USB at least)
1456 */
1457static void release_one_tty(struct work_struct *work)
1458{
1459 struct tty_struct *tty =
1460 container_of(work, struct tty_struct, hangup_work);
1461 struct tty_driver *driver = tty->driver;
1462
1463 if (tty->ops->cleanup)
1464 tty->ops->cleanup(tty);
1465
1466 tty->magic = 0;
1467 tty_driver_kref_put(driver);
1468 module_put(driver->owner);
1469
1470 spin_lock(&tty_files_lock);
1471 list_del_init(&tty->tty_files);
1472 spin_unlock(&tty_files_lock);
1473
1474 put_pid(tty->pgrp);
1475 put_pid(tty->session);
1476 free_tty_struct(tty);
1477}
1478
1479static void queue_release_one_tty(struct kref *kref)
1480{
1481 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1482
1483 if (tty->ops->shutdown)
1484 tty->ops->shutdown(tty);
1485 else
1486 tty_shutdown(tty);
1487
1488 /* The hangup queue is now free so we can reuse it rather than
1489 waste a chunk of memory for each port */
1490 INIT_WORK(&tty->hangup_work, release_one_tty);
1491 schedule_work(&tty->hangup_work);
1492}
1493
1494/**
1495 * tty_kref_put - release a tty kref
1496 * @tty: tty device
1497 *
1498 * Release a reference to a tty device and if need be let the kref
1499 * layer destruct the object for us
1500 */
1501
1502void tty_kref_put(struct tty_struct *tty)
1503{
1504 if (tty)
1505 kref_put(&tty->kref, queue_release_one_tty);
1506}
1507EXPORT_SYMBOL(tty_kref_put);
1508
1509/**
1510 * release_tty - release tty structure memory
1511 *
1512 * Release both @tty and a possible linked partner (think pty pair),
1513 * and decrement the refcount of the backing module.
1514 *
1515 * Locking:
1516 * tty_mutex - sometimes only
1517 * takes the file list lock internally when working on the list
1518 * of ttys that the driver keeps.
1519 * FIXME: should we require tty_mutex is held here ??
1520 *
1521 */
1522static void release_tty(struct tty_struct *tty, int idx)
1523{
1524 /* This should always be true but check for the moment */
1525 WARN_ON(tty->index != idx);
1526
1527 if (tty->link)
1528 tty_kref_put(tty->link);
1529 tty_kref_put(tty);
1530}
1531
1532/**
1533 * tty_release - vfs callback for close
1534 * @inode: inode of tty
1535 * @filp: file pointer for handle to tty
1536 *
1537 * Called the last time each file handle is closed that references
1538 * this tty. There may however be several such references.
1539 *
1540 * Locking:
1541 * Takes bkl. See tty_release_dev
1542 *
1543 * Even releasing the tty structures is a tricky business.. We have
1544 * to be very careful that the structures are all released at the
1545 * same time, as interrupts might otherwise get the wrong pointers.
1546 *
1547 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1548 * lead to double frees or releasing memory still in use.
1549 */
1550
1551int tty_release(struct inode *inode, struct file *filp)
1552{
1553 struct tty_struct *tty = file_tty(filp);
1554 struct tty_struct *o_tty;
1555 int pty_master, tty_closing, o_tty_closing, do_sleep;
1556 int devpts;
1557 int idx;
1558 char buf[64];
1559
1560 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1561 return 0;
1562
1563 tty_lock();
1564 check_tty_count(tty, "tty_release_dev");
1565
1566 __tty_fasync(-1, filp, 0);
1567
1568 idx = tty->index;
1569 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1570 tty->driver->subtype == PTY_TYPE_MASTER);
1571 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1572 o_tty = tty->link;
1573
1574#ifdef TTY_PARANOIA_CHECK
1575 if (idx < 0 || idx >= tty->driver->num) {
1576 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1577 "free (%s)\n", tty->name);
1578 tty_unlock();
1579 return 0;
1580 }
1581 if (!devpts) {
1582 if (tty != tty->driver->ttys[idx]) {
1583 tty_unlock();
1584 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1585 "for (%s)\n", idx, tty->name);
1586 return 0;
1587 }
1588 if (tty->termios != tty->driver->termios[idx]) {
1589 tty_unlock();
1590 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1591 "for (%s)\n",
1592 idx, tty->name);
1593 return 0;
1594 }
1595 }
1596#endif
1597
1598#ifdef TTY_DEBUG_HANGUP
1599 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1600 tty_name(tty, buf), tty->count);
1601#endif
1602
1603#ifdef TTY_PARANOIA_CHECK
1604 if (tty->driver->other &&
1605 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1606 if (o_tty != tty->driver->other->ttys[idx]) {
1607 tty_unlock();
1608 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1609 "not o_tty for (%s)\n",
1610 idx, tty->name);
1611 return 0 ;
1612 }
1613 if (o_tty->termios != tty->driver->other->termios[idx]) {
1614 tty_unlock();
1615 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1616 "not o_termios for (%s)\n",
1617 idx, tty->name);
1618 return 0;
1619 }
1620 if (o_tty->link != tty) {
1621 tty_unlock();
1622 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1623 return 0;
1624 }
1625 }
1626#endif
1627 if (tty->ops->close)
1628 tty->ops->close(tty, filp);
1629
1630 tty_unlock();
1631 /*
1632 * Sanity check: if tty->count is going to zero, there shouldn't be
1633 * any waiters on tty->read_wait or tty->write_wait. We test the
1634 * wait queues and kick everyone out _before_ actually starting to
1635 * close. This ensures that we won't block while releasing the tty
1636 * structure.
1637 *
1638 * The test for the o_tty closing is necessary, since the master and
1639 * slave sides may close in any order. If the slave side closes out
1640 * first, its count will be one, since the master side holds an open.
1641 * Thus this test wouldn't be triggered at the time the slave closes,
1642 * so we do it now.
1643 *
1644 * Note that it's possible for the tty to be opened again while we're
1645 * flushing out waiters. By recalculating the closing flags before
1646 * each iteration we avoid any problems.
1647 */
1648 while (1) {
1649 /* Guard against races with tty->count changes elsewhere and
1650 opens on /dev/tty */
1651
1652 mutex_lock(&tty_mutex);
1653 tty_lock();
1654 tty_closing = tty->count <= 1;
1655 o_tty_closing = o_tty &&
1656 (o_tty->count <= (pty_master ? 1 : 0));
1657 do_sleep = 0;
1658
1659 if (tty_closing) {
1660 if (waitqueue_active(&tty->read_wait)) {
1661 wake_up_poll(&tty->read_wait, POLLIN);
1662 do_sleep++;
1663 }
1664 if (waitqueue_active(&tty->write_wait)) {
1665 wake_up_poll(&tty->write_wait, POLLOUT);
1666 do_sleep++;
1667 }
1668 }
1669 if (o_tty_closing) {
1670 if (waitqueue_active(&o_tty->read_wait)) {
1671 wake_up_poll(&o_tty->read_wait, POLLIN);
1672 do_sleep++;
1673 }
1674 if (waitqueue_active(&o_tty->write_wait)) {
1675 wake_up_poll(&o_tty->write_wait, POLLOUT);
1676 do_sleep++;
1677 }
1678 }
1679 if (!do_sleep)
1680 break;
1681
1682 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1683 "active!\n", tty_name(tty, buf));
1684 tty_unlock();
1685 mutex_unlock(&tty_mutex);
1686 schedule();
1687 }
1688
1689 /*
1690 * The closing flags are now consistent with the open counts on
1691 * both sides, and we've completed the last operation that could
1692 * block, so it's safe to proceed with closing.
1693 */
1694 if (pty_master) {
1695 if (--o_tty->count < 0) {
1696 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1697 "(%d) for %s\n",
1698 o_tty->count, tty_name(o_tty, buf));
1699 o_tty->count = 0;
1700 }
1701 }
1702 if (--tty->count < 0) {
1703 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1704 tty->count, tty_name(tty, buf));
1705 tty->count = 0;
1706 }
1707
1708 /*
1709 * We've decremented tty->count, so we need to remove this file
1710 * descriptor off the tty->tty_files list; this serves two
1711 * purposes:
1712 * - check_tty_count sees the correct number of file descriptors
1713 * associated with this tty.
1714 * - do_tty_hangup no longer sees this file descriptor as
1715 * something that needs to be handled for hangups.
1716 */
1717 tty_del_file(filp);
1718
1719 /*
1720 * Perform some housekeeping before deciding whether to return.
1721 *
1722 * Set the TTY_CLOSING flag if this was the last open. In the
1723 * case of a pty we may have to wait around for the other side
1724 * to close, and TTY_CLOSING makes sure we can't be reopened.
1725 */
1726 if (tty_closing)
1727 set_bit(TTY_CLOSING, &tty->flags);
1728 if (o_tty_closing)
1729 set_bit(TTY_CLOSING, &o_tty->flags);
1730
1731 /*
1732 * If _either_ side is closing, make sure there aren't any
1733 * processes that still think tty or o_tty is their controlling
1734 * tty.
1735 */
1736 if (tty_closing || o_tty_closing) {
1737 read_lock(&tasklist_lock);
1738 session_clear_tty(tty->session);
1739 if (o_tty)
1740 session_clear_tty(o_tty->session);
1741 read_unlock(&tasklist_lock);
1742 }
1743
1744 mutex_unlock(&tty_mutex);
1745
1746 /* check whether both sides are closing ... */
1747 if (!tty_closing || (o_tty && !o_tty_closing)) {
1748 tty_unlock();
1749 return 0;
1750 }
1751
1752#ifdef TTY_DEBUG_HANGUP
1753 printk(KERN_DEBUG "freeing tty structure...");
1754#endif
1755 /*
1756 * Ask the line discipline code to release its structures
1757 */
1758 tty_ldisc_release(tty, o_tty);
1759 /*
1760 * The release_tty function takes care of the details of clearing
1761 * the slots and preserving the termios structure.
1762 */
1763 release_tty(tty, idx);
1764
1765 /* Make this pty number available for reallocation */
1766 if (devpts)
1767 devpts_kill_index(inode, idx);
1768 tty_unlock();
1769 return 0;
1770}
1771
1772/**
1773 * tty_open - open a tty device
1774 * @inode: inode of device file
1775 * @filp: file pointer to tty
1776 *
1777 * tty_open and tty_release keep up the tty count that contains the
1778 * number of opens done on a tty. We cannot use the inode-count, as
1779 * different inodes might point to the same tty.
1780 *
1781 * Open-counting is needed for pty masters, as well as for keeping
1782 * track of serial lines: DTR is dropped when the last close happens.
1783 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1784 *
1785 * The termios state of a pty is reset on first open so that
1786 * settings don't persist across reuse.
1787 *
1788 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1789 * tty->count should protect the rest.
1790 * ->siglock protects ->signal/->sighand
1791 */
1792
1793static int tty_open(struct inode *inode, struct file *filp)
1794{
1795 struct tty_struct *tty = NULL;
1796 int noctty, retval;
1797 struct tty_driver *driver;
1798 int index;
1799 dev_t device = inode->i_rdev;
1800 unsigned saved_flags = filp->f_flags;
1801
1802 nonseekable_open(inode, filp);
1803
1804retry_open:
1805 noctty = filp->f_flags & O_NOCTTY;
1806 index = -1;
1807 retval = 0;
1808
1809 mutex_lock(&tty_mutex);
1810 tty_lock();
1811
1812 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1813 tty = get_current_tty();
1814 if (!tty) {
1815 tty_unlock();
1816 mutex_unlock(&tty_mutex);
1817 return -ENXIO;
1818 }
1819 driver = tty_driver_kref_get(tty->driver);
1820 index = tty->index;
1821 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1822 /* noctty = 1; */
1823 /* FIXME: Should we take a driver reference ? */
1824 tty_kref_put(tty);
1825 goto got_driver;
1826 }
1827#ifdef CONFIG_VT
1828 if (device == MKDEV(TTY_MAJOR, 0)) {
1829 extern struct tty_driver *console_driver;
1830 driver = tty_driver_kref_get(console_driver);
1831 index = fg_console;
1832 noctty = 1;
1833 goto got_driver;
1834 }
1835#endif
1836 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1837 struct tty_driver *console_driver = console_device(&index);
1838 if (console_driver) {
1839 driver = tty_driver_kref_get(console_driver);
1840 if (driver) {
1841 /* Don't let /dev/console block */
1842 filp->f_flags |= O_NONBLOCK;
1843 noctty = 1;
1844 goto got_driver;
1845 }
1846 }
1847 tty_unlock();
1848 mutex_unlock(&tty_mutex);
1849 return -ENODEV;
1850 }
1851
1852 driver = get_tty_driver(device, &index);
1853 if (!driver) {
1854 tty_unlock();
1855 mutex_unlock(&tty_mutex);
1856 return -ENODEV;
1857 }
1858got_driver:
1859 if (!tty) {
1860 /* check whether we're reopening an existing tty */
1861 tty = tty_driver_lookup_tty(driver, inode, index);
1862
1863 if (IS_ERR(tty)) {
1864 tty_unlock();
1865 mutex_unlock(&tty_mutex);
1866 return PTR_ERR(tty);
1867 }
1868 }
1869
1870 if (tty) {
1871 retval = tty_reopen(tty);
1872 if (retval)
1873 tty = ERR_PTR(retval);
1874 } else
1875 tty = tty_init_dev(driver, index, 0);
1876
1877 mutex_unlock(&tty_mutex);
1878 tty_driver_kref_put(driver);
1879 if (IS_ERR(tty)) {
1880 tty_unlock();
1881 return PTR_ERR(tty);
1882 }
1883
1884 retval = tty_add_file(tty, filp);
1885 if (retval) {
1886 tty_unlock();
1887 return retval;
1888 }
1889
1890 check_tty_count(tty, "tty_open");
1891 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1892 tty->driver->subtype == PTY_TYPE_MASTER)
1893 noctty = 1;
1894#ifdef TTY_DEBUG_HANGUP
1895 printk(KERN_DEBUG "opening %s...", tty->name);
1896#endif
1897 if (!retval) {
1898 if (tty->ops->open)
1899 retval = tty->ops->open(tty, filp);
1900 else
1901 retval = -ENODEV;
1902 }
1903 filp->f_flags = saved_flags;
1904
1905 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1906 !capable(CAP_SYS_ADMIN))
1907 retval = -EBUSY;
1908
1909 if (retval) {
1910#ifdef TTY_DEBUG_HANGUP
1911 printk(KERN_DEBUG "error %d in opening %s...", retval,
1912 tty->name);
1913#endif
1914 tty_unlock(); /* need to call tty_release without BTM */
1915 tty_release(inode, filp);
1916 if (retval != -ERESTARTSYS)
1917 return retval;
1918
1919 if (signal_pending(current))
1920 return retval;
1921
1922 schedule();
1923 /*
1924 * Need to reset f_op in case a hangup happened.
1925 */
1926 tty_lock();
1927 if (filp->f_op == &hung_up_tty_fops)
1928 filp->f_op = &tty_fops;
1929 tty_unlock();
1930 goto retry_open;
1931 }
1932 tty_unlock();
1933
1934
1935 mutex_lock(&tty_mutex);
1936 tty_lock();
1937 spin_lock_irq(&current->sighand->siglock);
1938 if (!noctty &&
1939 current->signal->leader &&
1940 !current->signal->tty &&
1941 tty->session == NULL)
1942 __proc_set_tty(current, tty);
1943 spin_unlock_irq(&current->sighand->siglock);
1944 tty_unlock();
1945 mutex_unlock(&tty_mutex);
1946 return 0;
1947}
1948
1949
1950
1951/**
1952 * tty_poll - check tty status
1953 * @filp: file being polled
1954 * @wait: poll wait structures to update
1955 *
1956 * Call the line discipline polling method to obtain the poll
1957 * status of the device.
1958 *
1959 * Locking: locks called line discipline but ldisc poll method
1960 * may be re-entered freely by other callers.
1961 */
1962
1963static unsigned int tty_poll(struct file *filp, poll_table *wait)
1964{
1965 struct tty_struct *tty = file_tty(filp);
1966 struct tty_ldisc *ld;
1967 int ret = 0;
1968
1969 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1970 return 0;
1971
1972 ld = tty_ldisc_ref_wait(tty);
1973 if (ld->ops->poll)
1974 ret = (ld->ops->poll)(tty, filp, wait);
1975 tty_ldisc_deref(ld);
1976 return ret;
1977}
1978
1979static int __tty_fasync(int fd, struct file *filp, int on)
1980{
1981 struct tty_struct *tty = file_tty(filp);
1982 unsigned long flags;
1983 int retval = 0;
1984
1985 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1986 goto out;
1987
1988 retval = fasync_helper(fd, filp, on, &tty->fasync);
1989 if (retval <= 0)
1990 goto out;
1991
1992 if (on) {
1993 enum pid_type type;
1994 struct pid *pid;
1995 if (!waitqueue_active(&tty->read_wait))
1996 tty->minimum_to_wake = 1;
1997 spin_lock_irqsave(&tty->ctrl_lock, flags);
1998 if (tty->pgrp) {
1999 pid = tty->pgrp;
2000 type = PIDTYPE_PGID;
2001 } else {
2002 pid = task_pid(current);
2003 type = PIDTYPE_PID;
2004 }
2005 get_pid(pid);
2006 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2007 retval = __f_setown(filp, pid, type, 0);
2008 put_pid(pid);
2009 if (retval)
2010 goto out;
2011 } else {
2012 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2013 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2014 }
2015 retval = 0;
2016out:
2017 return retval;
2018}
2019
2020static int tty_fasync(int fd, struct file *filp, int on)
2021{
2022 int retval;
2023 tty_lock();
2024 retval = __tty_fasync(fd, filp, on);
2025 tty_unlock();
2026 return retval;
2027}
2028
2029/**
2030 * tiocsti - fake input character
2031 * @tty: tty to fake input into
2032 * @p: pointer to character
2033 *
2034 * Fake input to a tty device. Does the necessary locking and
2035 * input management.
2036 *
2037 * FIXME: does not honour flow control ??
2038 *
2039 * Locking:
2040 * Called functions take tty_ldisc_lock
2041 * current->signal->tty check is safe without locks
2042 *
2043 * FIXME: may race normal receive processing
2044 */
2045
2046static int tiocsti(struct tty_struct *tty, char __user *p)
2047{
2048 char ch, mbz = 0;
2049 struct tty_ldisc *ld;
2050
2051 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2052 return -EPERM;
2053 if (get_user(ch, p))
2054 return -EFAULT;
2055 tty_audit_tiocsti(tty, ch);
2056 ld = tty_ldisc_ref_wait(tty);
2057 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2058 tty_ldisc_deref(ld);
2059 return 0;
2060}
2061
2062/**
2063 * tiocgwinsz - implement window query ioctl
2064 * @tty; tty
2065 * @arg: user buffer for result
2066 *
2067 * Copies the kernel idea of the window size into the user buffer.
2068 *
2069 * Locking: tty->termios_mutex is taken to ensure the winsize data
2070 * is consistent.
2071 */
2072
2073static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2074{
2075 int err;
2076
2077 mutex_lock(&tty->termios_mutex);
2078 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2079 mutex_unlock(&tty->termios_mutex);
2080
2081 return err ? -EFAULT: 0;
2082}
2083
2084/**
2085 * tty_do_resize - resize event
2086 * @tty: tty being resized
2087 * @rows: rows (character)
2088 * @cols: cols (character)
2089 *
2090 * Update the termios variables and send the necessary signals to
2091 * peform a terminal resize correctly
2092 */
2093
2094int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2095{
2096 struct pid *pgrp;
2097 unsigned long flags;
2098
2099 /* Lock the tty */
2100 mutex_lock(&tty->termios_mutex);
2101 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2102 goto done;
2103 /* Get the PID values and reference them so we can
2104 avoid holding the tty ctrl lock while sending signals */
2105 spin_lock_irqsave(&tty->ctrl_lock, flags);
2106 pgrp = get_pid(tty->pgrp);
2107 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2108
2109 if (pgrp)
2110 kill_pgrp(pgrp, SIGWINCH, 1);
2111 put_pid(pgrp);
2112
2113 tty->winsize = *ws;
2114done:
2115 mutex_unlock(&tty->termios_mutex);
2116 return 0;
2117}
2118
2119/**
2120 * tiocswinsz - implement window size set ioctl
2121 * @tty; tty side of tty
2122 * @arg: user buffer for result
2123 *
2124 * Copies the user idea of the window size to the kernel. Traditionally
2125 * this is just advisory information but for the Linux console it
2126 * actually has driver level meaning and triggers a VC resize.
2127 *
2128 * Locking:
2129 * Driver dependant. The default do_resize method takes the
2130 * tty termios mutex and ctrl_lock. The console takes its own lock
2131 * then calls into the default method.
2132 */
2133
2134static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2135{
2136 struct winsize tmp_ws;
2137 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2138 return -EFAULT;
2139
2140 if (tty->ops->resize)
2141 return tty->ops->resize(tty, &tmp_ws);
2142 else
2143 return tty_do_resize(tty, &tmp_ws);
2144}
2145
2146/**
2147 * tioccons - allow admin to move logical console
2148 * @file: the file to become console
2149 *
2150 * Allow the adminstrator to move the redirected console device
2151 *
2152 * Locking: uses redirect_lock to guard the redirect information
2153 */
2154
2155static int tioccons(struct file *file)
2156{
2157 if (!capable(CAP_SYS_ADMIN))
2158 return -EPERM;
2159 if (file->f_op->write == redirected_tty_write) {
2160 struct file *f;
2161 spin_lock(&redirect_lock);
2162 f = redirect;
2163 redirect = NULL;
2164 spin_unlock(&redirect_lock);
2165 if (f)
2166 fput(f);
2167 return 0;
2168 }
2169 spin_lock(&redirect_lock);
2170 if (redirect) {
2171 spin_unlock(&redirect_lock);
2172 return -EBUSY;
2173 }
2174 get_file(file);
2175 redirect = file;
2176 spin_unlock(&redirect_lock);
2177 return 0;
2178}
2179
2180/**
2181 * fionbio - non blocking ioctl
2182 * @file: file to set blocking value
2183 * @p: user parameter
2184 *
2185 * Historical tty interfaces had a blocking control ioctl before
2186 * the generic functionality existed. This piece of history is preserved
2187 * in the expected tty API of posix OS's.
2188 *
2189 * Locking: none, the open file handle ensures it won't go away.
2190 */
2191
2192static int fionbio(struct file *file, int __user *p)
2193{
2194 int nonblock;
2195
2196 if (get_user(nonblock, p))
2197 return -EFAULT;
2198
2199 spin_lock(&file->f_lock);
2200 if (nonblock)
2201 file->f_flags |= O_NONBLOCK;
2202 else
2203 file->f_flags &= ~O_NONBLOCK;
2204 spin_unlock(&file->f_lock);
2205 return 0;
2206}
2207
2208/**
2209 * tiocsctty - set controlling tty
2210 * @tty: tty structure
2211 * @arg: user argument
2212 *
2213 * This ioctl is used to manage job control. It permits a session
2214 * leader to set this tty as the controlling tty for the session.
2215 *
2216 * Locking:
2217 * Takes tty_mutex() to protect tty instance
2218 * Takes tasklist_lock internally to walk sessions
2219 * Takes ->siglock() when updating signal->tty
2220 */
2221
2222static int tiocsctty(struct tty_struct *tty, int arg)
2223{
2224 int ret = 0;
2225 if (current->signal->leader && (task_session(current) == tty->session))
2226 return ret;
2227
2228 mutex_lock(&tty_mutex);
2229 /*
2230 * The process must be a session leader and
2231 * not have a controlling tty already.
2232 */
2233 if (!current->signal->leader || current->signal->tty) {
2234 ret = -EPERM;
2235 goto unlock;
2236 }
2237
2238 if (tty->session) {
2239 /*
2240 * This tty is already the controlling
2241 * tty for another session group!
2242 */
2243 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2244 /*
2245 * Steal it away
2246 */
2247 read_lock(&tasklist_lock);
2248 session_clear_tty(tty->session);
2249 read_unlock(&tasklist_lock);
2250 } else {
2251 ret = -EPERM;
2252 goto unlock;
2253 }
2254 }
2255 proc_set_tty(current, tty);
2256unlock:
2257 mutex_unlock(&tty_mutex);
2258 return ret;
2259}
2260
2261/**
2262 * tty_get_pgrp - return a ref counted pgrp pid
2263 * @tty: tty to read
2264 *
2265 * Returns a refcounted instance of the pid struct for the process
2266 * group controlling the tty.
2267 */
2268
2269struct pid *tty_get_pgrp(struct tty_struct *tty)
2270{
2271 unsigned long flags;
2272 struct pid *pgrp;
2273
2274 spin_lock_irqsave(&tty->ctrl_lock, flags);
2275 pgrp = get_pid(tty->pgrp);
2276 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2277
2278 return pgrp;
2279}
2280EXPORT_SYMBOL_GPL(tty_get_pgrp);
2281
2282/**
2283 * tiocgpgrp - get process group
2284 * @tty: tty passed by user
2285 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2286 * @p: returned pid
2287 *
2288 * Obtain the process group of the tty. If there is no process group
2289 * return an error.
2290 *
2291 * Locking: none. Reference to current->signal->tty is safe.
2292 */
2293
2294static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2295{
2296 struct pid *pid;
2297 int ret;
2298 /*
2299 * (tty == real_tty) is a cheap way of
2300 * testing if the tty is NOT a master pty.
2301 */
2302 if (tty == real_tty && current->signal->tty != real_tty)
2303 return -ENOTTY;
2304 pid = tty_get_pgrp(real_tty);
2305 ret = put_user(pid_vnr(pid), p);
2306 put_pid(pid);
2307 return ret;
2308}
2309
2310/**
2311 * tiocspgrp - attempt to set process group
2312 * @tty: tty passed by user
2313 * @real_tty: tty side device matching tty passed by user
2314 * @p: pid pointer
2315 *
2316 * Set the process group of the tty to the session passed. Only
2317 * permitted where the tty session is our session.
2318 *
2319 * Locking: RCU, ctrl lock
2320 */
2321
2322static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2323{
2324 struct pid *pgrp;
2325 pid_t pgrp_nr;
2326 int retval = tty_check_change(real_tty);
2327 unsigned long flags;
2328
2329 if (retval == -EIO)
2330 return -ENOTTY;
2331 if (retval)
2332 return retval;
2333 if (!current->signal->tty ||
2334 (current->signal->tty != real_tty) ||
2335 (real_tty->session != task_session(current)))
2336 return -ENOTTY;
2337 if (get_user(pgrp_nr, p))
2338 return -EFAULT;
2339 if (pgrp_nr < 0)
2340 return -EINVAL;
2341 rcu_read_lock();
2342 pgrp = find_vpid(pgrp_nr);
2343 retval = -ESRCH;
2344 if (!pgrp)
2345 goto out_unlock;
2346 retval = -EPERM;
2347 if (session_of_pgrp(pgrp) != task_session(current))
2348 goto out_unlock;
2349 retval = 0;
2350 spin_lock_irqsave(&tty->ctrl_lock, flags);
2351 put_pid(real_tty->pgrp);
2352 real_tty->pgrp = get_pid(pgrp);
2353 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2354out_unlock:
2355 rcu_read_unlock();
2356 return retval;
2357}
2358
2359/**
2360 * tiocgsid - get session id
2361 * @tty: tty passed by user
2362 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2363 * @p: pointer to returned session id
2364 *
2365 * Obtain the session id of the tty. If there is no session
2366 * return an error.
2367 *
2368 * Locking: none. Reference to current->signal->tty is safe.
2369 */
2370
2371static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2372{
2373 /*
2374 * (tty == real_tty) is a cheap way of
2375 * testing if the tty is NOT a master pty.
2376 */
2377 if (tty == real_tty && current->signal->tty != real_tty)
2378 return -ENOTTY;
2379 if (!real_tty->session)
2380 return -ENOTTY;
2381 return put_user(pid_vnr(real_tty->session), p);
2382}
2383
2384/**
2385 * tiocsetd - set line discipline
2386 * @tty: tty device
2387 * @p: pointer to user data
2388 *
2389 * Set the line discipline according to user request.
2390 *
2391 * Locking: see tty_set_ldisc, this function is just a helper
2392 */
2393
2394static int tiocsetd(struct tty_struct *tty, int __user *p)
2395{
2396 int ldisc;
2397 int ret;
2398
2399 if (get_user(ldisc, p))
2400 return -EFAULT;
2401
2402 ret = tty_set_ldisc(tty, ldisc);
2403
2404 return ret;
2405}
2406
2407/**
2408 * send_break - performed time break
2409 * @tty: device to break on
2410 * @duration: timeout in mS
2411 *
2412 * Perform a timed break on hardware that lacks its own driver level
2413 * timed break functionality.
2414 *
2415 * Locking:
2416 * atomic_write_lock serializes
2417 *
2418 */
2419
2420static int send_break(struct tty_struct *tty, unsigned int duration)
2421{
2422 int retval;
2423
2424 if (tty->ops->break_ctl == NULL)
2425 return 0;
2426
2427 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2428 retval = tty->ops->break_ctl(tty, duration);
2429 else {
2430 /* Do the work ourselves */
2431 if (tty_write_lock(tty, 0) < 0)
2432 return -EINTR;
2433 retval = tty->ops->break_ctl(tty, -1);
2434 if (retval)
2435 goto out;
2436 if (!signal_pending(current))
2437 msleep_interruptible(duration);
2438 retval = tty->ops->break_ctl(tty, 0);
2439out:
2440 tty_write_unlock(tty);
2441 if (signal_pending(current))
2442 retval = -EINTR;
2443 }
2444 return retval;
2445}
2446
2447/**
2448 * tty_tiocmget - get modem status
2449 * @tty: tty device
2450 * @file: user file pointer
2451 * @p: pointer to result
2452 *
2453 * Obtain the modem status bits from the tty driver if the feature
2454 * is supported. Return -EINVAL if it is not available.
2455 *
2456 * Locking: none (up to the driver)
2457 */
2458
2459static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2460{
2461 int retval = -EINVAL;
2462
2463 if (tty->ops->tiocmget) {
2464 retval = tty->ops->tiocmget(tty, file);
2465
2466 if (retval >= 0)
2467 retval = put_user(retval, p);
2468 }
2469 return retval;
2470}
2471
2472/**
2473 * tty_tiocmset - set modem status
2474 * @tty: tty device
2475 * @file: user file pointer
2476 * @cmd: command - clear bits, set bits or set all
2477 * @p: pointer to desired bits
2478 *
2479 * Set the modem status bits from the tty driver if the feature
2480 * is supported. Return -EINVAL if it is not available.
2481 *
2482 * Locking: none (up to the driver)
2483 */
2484
2485static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2486 unsigned __user *p)
2487{
2488 int retval;
2489 unsigned int set, clear, val;
2490
2491 if (tty->ops->tiocmset == NULL)
2492 return -EINVAL;
2493
2494 retval = get_user(val, p);
2495 if (retval)
2496 return retval;
2497 set = clear = 0;
2498 switch (cmd) {
2499 case TIOCMBIS:
2500 set = val;
2501 break;
2502 case TIOCMBIC:
2503 clear = val;
2504 break;
2505 case TIOCMSET:
2506 set = val;
2507 clear = ~val;
2508 break;
2509 }
2510 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2511 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2512 return tty->ops->tiocmset(tty, file, set, clear);
2513}
2514
2515static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2516{
2517 int retval = -EINVAL;
2518 struct serial_icounter_struct icount;
2519 memset(&icount, 0, sizeof(icount));
2520 if (tty->ops->get_icount)
2521 retval = tty->ops->get_icount(tty, &icount);
2522 if (retval != 0)
2523 return retval;
2524 if (copy_to_user(arg, &icount, sizeof(icount)))
2525 return -EFAULT;
2526 return 0;
2527}
2528
2529struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2530{
2531 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2532 tty->driver->subtype == PTY_TYPE_MASTER)
2533 tty = tty->link;
2534 return tty;
2535}
2536EXPORT_SYMBOL(tty_pair_get_tty);
2537
2538struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2539{
2540 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2541 tty->driver->subtype == PTY_TYPE_MASTER)
2542 return tty;
2543 return tty->link;
2544}
2545EXPORT_SYMBOL(tty_pair_get_pty);
2546
2547/*
2548 * Split this up, as gcc can choke on it otherwise..
2549 */
2550long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2551{
2552 struct tty_struct *tty = file_tty(file);
2553 struct tty_struct *real_tty;
2554 void __user *p = (void __user *)arg;
2555 int retval;
2556 struct tty_ldisc *ld;
2557 struct inode *inode = file->f_dentry->d_inode;
2558
2559 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2560 return -EINVAL;
2561
2562 real_tty = tty_pair_get_tty(tty);
2563
2564 /*
2565 * Factor out some common prep work
2566 */
2567 switch (cmd) {
2568 case TIOCSETD:
2569 case TIOCSBRK:
2570 case TIOCCBRK:
2571 case TCSBRK:
2572 case TCSBRKP:
2573 retval = tty_check_change(tty);
2574 if (retval)
2575 return retval;
2576 if (cmd != TIOCCBRK) {
2577 tty_wait_until_sent(tty, 0);
2578 if (signal_pending(current))
2579 return -EINTR;
2580 }
2581 break;
2582 }
2583
2584 /*
2585 * Now do the stuff.
2586 */
2587 switch (cmd) {
2588 case TIOCSTI:
2589 return tiocsti(tty, p);
2590 case TIOCGWINSZ:
2591 return tiocgwinsz(real_tty, p);
2592 case TIOCSWINSZ:
2593 return tiocswinsz(real_tty, p);
2594 case TIOCCONS:
2595 return real_tty != tty ? -EINVAL : tioccons(file);
2596 case FIONBIO:
2597 return fionbio(file, p);
2598 case TIOCEXCL:
2599 set_bit(TTY_EXCLUSIVE, &tty->flags);
2600 return 0;
2601 case TIOCNXCL:
2602 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2603 return 0;
2604 case TIOCNOTTY:
2605 if (current->signal->tty != tty)
2606 return -ENOTTY;
2607 no_tty();
2608 return 0;
2609 case TIOCSCTTY:
2610 return tiocsctty(tty, arg);
2611 case TIOCGPGRP:
2612 return tiocgpgrp(tty, real_tty, p);
2613 case TIOCSPGRP:
2614 return tiocspgrp(tty, real_tty, p);
2615 case TIOCGSID:
2616 return tiocgsid(tty, real_tty, p);
2617 case TIOCGETD:
2618 return put_user(tty->ldisc->ops->num, (int __user *)p);
2619 case TIOCSETD:
2620 return tiocsetd(tty, p);
2621 /*
2622 * Break handling
2623 */
2624 case TIOCSBRK: /* Turn break on, unconditionally */
2625 if (tty->ops->break_ctl)
2626 return tty->ops->break_ctl(tty, -1);
2627 return 0;
2628 case TIOCCBRK: /* Turn break off, unconditionally */
2629 if (tty->ops->break_ctl)
2630 return tty->ops->break_ctl(tty, 0);
2631 return 0;
2632 case TCSBRK: /* SVID version: non-zero arg --> no break */
2633 /* non-zero arg means wait for all output data
2634 * to be sent (performed above) but don't send break.
2635 * This is used by the tcdrain() termios function.
2636 */
2637 if (!arg)
2638 return send_break(tty, 250);
2639 return 0;
2640 case TCSBRKP: /* support for POSIX tcsendbreak() */
2641 return send_break(tty, arg ? arg*100 : 250);
2642
2643 case TIOCMGET:
2644 return tty_tiocmget(tty, file, p);
2645 case TIOCMSET:
2646 case TIOCMBIC:
2647 case TIOCMBIS:
2648 return tty_tiocmset(tty, file, cmd, p);
2649 case TIOCGICOUNT:
2650 retval = tty_tiocgicount(tty, p);
2651 /* For the moment allow fall through to the old method */
2652 if (retval != -EINVAL)
2653 return retval;
2654 break;
2655 case TCFLSH:
2656 switch (arg) {
2657 case TCIFLUSH:
2658 case TCIOFLUSH:
2659 /* flush tty buffer and allow ldisc to process ioctl */
2660 tty_buffer_flush(tty);
2661 break;
2662 }
2663 break;
2664 }
2665 if (tty->ops->ioctl) {
2666 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2667 if (retval != -ENOIOCTLCMD)
2668 return retval;
2669 }
2670 ld = tty_ldisc_ref_wait(tty);
2671 retval = -EINVAL;
2672 if (ld->ops->ioctl) {
2673 retval = ld->ops->ioctl(tty, file, cmd, arg);
2674 if (retval == -ENOIOCTLCMD)
2675 retval = -EINVAL;
2676 }
2677 tty_ldisc_deref(ld);
2678 return retval;
2679}
2680
2681#ifdef CONFIG_COMPAT
2682static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2683 unsigned long arg)
2684{
2685 struct inode *inode = file->f_dentry->d_inode;
2686 struct tty_struct *tty = file_tty(file);
2687 struct tty_ldisc *ld;
2688 int retval = -ENOIOCTLCMD;
2689
2690 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2691 return -EINVAL;
2692
2693 if (tty->ops->compat_ioctl) {
2694 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2695 if (retval != -ENOIOCTLCMD)
2696 return retval;
2697 }
2698
2699 ld = tty_ldisc_ref_wait(tty);
2700 if (ld->ops->compat_ioctl)
2701 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2702 tty_ldisc_deref(ld);
2703
2704 return retval;
2705}
2706#endif
2707
2708/*
2709 * This implements the "Secure Attention Key" --- the idea is to
2710 * prevent trojan horses by killing all processes associated with this
2711 * tty when the user hits the "Secure Attention Key". Required for
2712 * super-paranoid applications --- see the Orange Book for more details.
2713 *
2714 * This code could be nicer; ideally it should send a HUP, wait a few
2715 * seconds, then send a INT, and then a KILL signal. But you then
2716 * have to coordinate with the init process, since all processes associated
2717 * with the current tty must be dead before the new getty is allowed
2718 * to spawn.
2719 *
2720 * Now, if it would be correct ;-/ The current code has a nasty hole -
2721 * it doesn't catch files in flight. We may send the descriptor to ourselves
2722 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2723 *
2724 * Nasty bug: do_SAK is being called in interrupt context. This can
2725 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2726 */
2727void __do_SAK(struct tty_struct *tty)
2728{
2729#ifdef TTY_SOFT_SAK
2730 tty_hangup(tty);
2731#else
2732 struct task_struct *g, *p;
2733 struct pid *session;
2734 int i;
2735 struct file *filp;
2736 struct fdtable *fdt;
2737
2738 if (!tty)
2739 return;
2740 session = tty->session;
2741
2742 tty_ldisc_flush(tty);
2743
2744 tty_driver_flush_buffer(tty);
2745
2746 read_lock(&tasklist_lock);
2747 /* Kill the entire session */
2748 do_each_pid_task(session, PIDTYPE_SID, p) {
2749 printk(KERN_NOTICE "SAK: killed process %d"
2750 " (%s): task_session(p)==tty->session\n",
2751 task_pid_nr(p), p->comm);
2752 send_sig(SIGKILL, p, 1);
2753 } while_each_pid_task(session, PIDTYPE_SID, p);
2754 /* Now kill any processes that happen to have the
2755 * tty open.
2756 */
2757 do_each_thread(g, p) {
2758 if (p->signal->tty == tty) {
2759 printk(KERN_NOTICE "SAK: killed process %d"
2760 " (%s): task_session(p)==tty->session\n",
2761 task_pid_nr(p), p->comm);
2762 send_sig(SIGKILL, p, 1);
2763 continue;
2764 }
2765 task_lock(p);
2766 if (p->files) {
2767 /*
2768 * We don't take a ref to the file, so we must
2769 * hold ->file_lock instead.
2770 */
2771 spin_lock(&p->files->file_lock);
2772 fdt = files_fdtable(p->files);
2773 for (i = 0; i < fdt->max_fds; i++) {
2774 filp = fcheck_files(p->files, i);
2775 if (!filp)
2776 continue;
2777 if (filp->f_op->read == tty_read &&
2778 file_tty(filp) == tty) {
2779 printk(KERN_NOTICE "SAK: killed process %d"
2780 " (%s): fd#%d opened to the tty\n",
2781 task_pid_nr(p), p->comm, i);
2782 force_sig(SIGKILL, p);
2783 break;
2784 }
2785 }
2786 spin_unlock(&p->files->file_lock);
2787 }
2788 task_unlock(p);
2789 } while_each_thread(g, p);
2790 read_unlock(&tasklist_lock);
2791#endif
2792}
2793
2794static void do_SAK_work(struct work_struct *work)
2795{
2796 struct tty_struct *tty =
2797 container_of(work, struct tty_struct, SAK_work);
2798 __do_SAK(tty);
2799}
2800
2801/*
2802 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2803 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2804 * the values which we write to it will be identical to the values which it
2805 * already has. --akpm
2806 */
2807void do_SAK(struct tty_struct *tty)
2808{
2809 if (!tty)
2810 return;
2811 schedule_work(&tty->SAK_work);
2812}
2813
2814EXPORT_SYMBOL(do_SAK);
2815
2816static int dev_match_devt(struct device *dev, void *data)
2817{
2818 dev_t *devt = data;
2819 return dev->devt == *devt;
2820}
2821
2822/* Must put_device() after it's unused! */
2823static struct device *tty_get_device(struct tty_struct *tty)
2824{
2825 dev_t devt = tty_devnum(tty);
2826 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2827}
2828
2829
2830/**
2831 * initialize_tty_struct
2832 * @tty: tty to initialize
2833 *
2834 * This subroutine initializes a tty structure that has been newly
2835 * allocated.
2836 *
2837 * Locking: none - tty in question must not be exposed at this point
2838 */
2839
2840void initialize_tty_struct(struct tty_struct *tty,
2841 struct tty_driver *driver, int idx)
2842{
2843 memset(tty, 0, sizeof(struct tty_struct));
2844 kref_init(&tty->kref);
2845 tty->magic = TTY_MAGIC;
2846 tty_ldisc_init(tty);
2847 tty->session = NULL;
2848 tty->pgrp = NULL;
2849 tty->overrun_time = jiffies;
2850 tty->buf.head = tty->buf.tail = NULL;
2851 tty_buffer_init(tty);
2852 mutex_init(&tty->termios_mutex);
2853 mutex_init(&tty->ldisc_mutex);
2854 init_waitqueue_head(&tty->write_wait);
2855 init_waitqueue_head(&tty->read_wait);
2856 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2857 mutex_init(&tty->atomic_read_lock);
2858 mutex_init(&tty->atomic_write_lock);
2859 mutex_init(&tty->output_lock);
2860 mutex_init(&tty->echo_lock);
2861 spin_lock_init(&tty->read_lock);
2862 spin_lock_init(&tty->ctrl_lock);
2863 INIT_LIST_HEAD(&tty->tty_files);
2864 INIT_WORK(&tty->SAK_work, do_SAK_work);
2865
2866 tty->driver = driver;
2867 tty->ops = driver->ops;
2868 tty->index = idx;
2869 tty_line_name(driver, idx, tty->name);
2870 tty->dev = tty_get_device(tty);
2871}
2872
2873/**
2874 * tty_put_char - write one character to a tty
2875 * @tty: tty
2876 * @ch: character
2877 *
2878 * Write one byte to the tty using the provided put_char method
2879 * if present. Returns the number of characters successfully output.
2880 *
2881 * Note: the specific put_char operation in the driver layer may go
2882 * away soon. Don't call it directly, use this method
2883 */
2884
2885int tty_put_char(struct tty_struct *tty, unsigned char ch)
2886{
2887 if (tty->ops->put_char)
2888 return tty->ops->put_char(tty, ch);
2889 return tty->ops->write(tty, &ch, 1);
2890}
2891EXPORT_SYMBOL_GPL(tty_put_char);
2892
2893struct class *tty_class;
2894
2895/**
2896 * tty_register_device - register a tty device
2897 * @driver: the tty driver that describes the tty device
2898 * @index: the index in the tty driver for this tty device
2899 * @device: a struct device that is associated with this tty device.
2900 * This field is optional, if there is no known struct device
2901 * for this tty device it can be set to NULL safely.
2902 *
2903 * Returns a pointer to the struct device for this tty device
2904 * (or ERR_PTR(-EFOO) on error).
2905 *
2906 * This call is required to be made to register an individual tty device
2907 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2908 * that bit is not set, this function should not be called by a tty
2909 * driver.
2910 *
2911 * Locking: ??
2912 */
2913
2914struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2915 struct device *device)
2916{
2917 char name[64];
2918 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2919
2920 if (index >= driver->num) {
2921 printk(KERN_ERR "Attempt to register invalid tty line number "
2922 " (%d).\n", index);
2923 return ERR_PTR(-EINVAL);
2924 }
2925
2926 if (driver->type == TTY_DRIVER_TYPE_PTY)
2927 pty_line_name(driver, index, name);
2928 else
2929 tty_line_name(driver, index, name);
2930
2931 return device_create(tty_class, device, dev, NULL, name);
2932}
2933EXPORT_SYMBOL(tty_register_device);
2934
2935/**
2936 * tty_unregister_device - unregister a tty device
2937 * @driver: the tty driver that describes the tty device
2938 * @index: the index in the tty driver for this tty device
2939 *
2940 * If a tty device is registered with a call to tty_register_device() then
2941 * this function must be called when the tty device is gone.
2942 *
2943 * Locking: ??
2944 */
2945
2946void tty_unregister_device(struct tty_driver *driver, unsigned index)
2947{
2948 device_destroy(tty_class,
2949 MKDEV(driver->major, driver->minor_start) + index);
2950}
2951EXPORT_SYMBOL(tty_unregister_device);
2952
2953struct tty_driver *alloc_tty_driver(int lines)
2954{
2955 struct tty_driver *driver;
2956
2957 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2958 if (driver) {
2959 kref_init(&driver->kref);
2960 driver->magic = TTY_DRIVER_MAGIC;
2961 driver->num = lines;
2962 /* later we'll move allocation of tables here */
2963 }
2964 return driver;
2965}
2966EXPORT_SYMBOL(alloc_tty_driver);
2967
2968static void destruct_tty_driver(struct kref *kref)
2969{
2970 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2971 int i;
2972 struct ktermios *tp;
2973 void *p;
2974
2975 if (driver->flags & TTY_DRIVER_INSTALLED) {
2976 /*
2977 * Free the termios and termios_locked structures because
2978 * we don't want to get memory leaks when modular tty
2979 * drivers are removed from the kernel.
2980 */
2981 for (i = 0; i < driver->num; i++) {
2982 tp = driver->termios[i];
2983 if (tp) {
2984 driver->termios[i] = NULL;
2985 kfree(tp);
2986 }
2987 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2988 tty_unregister_device(driver, i);
2989 }
2990 p = driver->ttys;
2991 proc_tty_unregister_driver(driver);
2992 driver->ttys = NULL;
2993 driver->termios = NULL;
2994 kfree(p);
2995 cdev_del(&driver->cdev);
2996 }
2997 kfree(driver);
2998}
2999
3000void tty_driver_kref_put(struct tty_driver *driver)
3001{
3002 kref_put(&driver->kref, destruct_tty_driver);
3003}
3004EXPORT_SYMBOL(tty_driver_kref_put);
3005
3006void tty_set_operations(struct tty_driver *driver,
3007 const struct tty_operations *op)
3008{
3009 driver->ops = op;
3010};
3011EXPORT_SYMBOL(tty_set_operations);
3012
3013void put_tty_driver(struct tty_driver *d)
3014{
3015 tty_driver_kref_put(d);
3016}
3017EXPORT_SYMBOL(put_tty_driver);
3018
3019/*
3020 * Called by a tty driver to register itself.
3021 */
3022int tty_register_driver(struct tty_driver *driver)
3023{
3024 int error;
3025 int i;
3026 dev_t dev;
3027 void **p = NULL;
3028 struct device *d;
3029
3030 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3031 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3032 if (!p)
3033 return -ENOMEM;
3034 }
3035
3036 if (!driver->major) {
3037 error = alloc_chrdev_region(&dev, driver->minor_start,
3038 driver->num, driver->name);
3039 if (!error) {
3040 driver->major = MAJOR(dev);
3041 driver->minor_start = MINOR(dev);
3042 }
3043 } else {
3044 dev = MKDEV(driver->major, driver->minor_start);
3045 error = register_chrdev_region(dev, driver->num, driver->name);
3046 }
3047 if (error < 0) {
3048 kfree(p);
3049 return error;
3050 }
3051
3052 if (p) {
3053 driver->ttys = (struct tty_struct **)p;
3054 driver->termios = (struct ktermios **)(p + driver->num);
3055 } else {
3056 driver->ttys = NULL;
3057 driver->termios = NULL;
3058 }
3059
3060 cdev_init(&driver->cdev, &tty_fops);
3061 driver->cdev.owner = driver->owner;
3062 error = cdev_add(&driver->cdev, dev, driver->num);
3063 if (error) {
3064 unregister_chrdev_region(dev, driver->num);
3065 driver->ttys = NULL;
3066 driver->termios = NULL;
3067 kfree(p);
3068 return error;
3069 }
3070
3071 mutex_lock(&tty_mutex);
3072 list_add(&driver->tty_drivers, &tty_drivers);
3073 mutex_unlock(&tty_mutex);
3074
3075 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3076 for (i = 0; i < driver->num; i++) {
3077 d = tty_register_device(driver, i, NULL);
3078 if (IS_ERR(d)) {
3079 error = PTR_ERR(d);
3080 goto err;
3081 }
3082 }
3083 }
3084 proc_tty_register_driver(driver);
3085 driver->flags |= TTY_DRIVER_INSTALLED;
3086 return 0;
3087
3088err:
3089 for (i--; i >= 0; i--)
3090 tty_unregister_device(driver, i);
3091
3092 mutex_lock(&tty_mutex);
3093 list_del(&driver->tty_drivers);
3094 mutex_unlock(&tty_mutex);
3095
3096 unregister_chrdev_region(dev, driver->num);
3097 driver->ttys = NULL;
3098 driver->termios = NULL;
3099 kfree(p);
3100 return error;
3101}
3102
3103EXPORT_SYMBOL(tty_register_driver);
3104
3105/*
3106 * Called by a tty driver to unregister itself.
3107 */
3108int tty_unregister_driver(struct tty_driver *driver)
3109{
3110#if 0
3111 /* FIXME */
3112 if (driver->refcount)
3113 return -EBUSY;
3114#endif
3115 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3116 driver->num);
3117 mutex_lock(&tty_mutex);
3118 list_del(&driver->tty_drivers);
3119 mutex_unlock(&tty_mutex);
3120 return 0;
3121}
3122
3123EXPORT_SYMBOL(tty_unregister_driver);
3124
3125dev_t tty_devnum(struct tty_struct *tty)
3126{
3127 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3128}
3129EXPORT_SYMBOL(tty_devnum);
3130
3131void proc_clear_tty(struct task_struct *p)
3132{
3133 unsigned long flags;
3134 struct tty_struct *tty;
3135 spin_lock_irqsave(&p->sighand->siglock, flags);
3136 tty = p->signal->tty;
3137 p->signal->tty = NULL;
3138 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3139 tty_kref_put(tty);
3140}
3141
3142/* Called under the sighand lock */
3143
3144static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3145{
3146 if (tty) {
3147 unsigned long flags;
3148 /* We should not have a session or pgrp to put here but.... */
3149 spin_lock_irqsave(&tty->ctrl_lock, flags);
3150 put_pid(tty->session);
3151 put_pid(tty->pgrp);
3152 tty->pgrp = get_pid(task_pgrp(tsk));
3153 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3154 tty->session = get_pid(task_session(tsk));
3155 if (tsk->signal->tty) {
3156 printk(KERN_DEBUG "tty not NULL!!\n");
3157 tty_kref_put(tsk->signal->tty);
3158 }
3159 }
3160 put_pid(tsk->signal->tty_old_pgrp);
3161 tsk->signal->tty = tty_kref_get(tty);
3162 tsk->signal->tty_old_pgrp = NULL;
3163}
3164
3165static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3166{
3167 spin_lock_irq(&tsk->sighand->siglock);
3168 __proc_set_tty(tsk, tty);
3169 spin_unlock_irq(&tsk->sighand->siglock);
3170}
3171
3172struct tty_struct *get_current_tty(void)
3173{
3174 struct tty_struct *tty;
3175 unsigned long flags;
3176
3177 spin_lock_irqsave(&current->sighand->siglock, flags);
3178 tty = tty_kref_get(current->signal->tty);
3179 spin_unlock_irqrestore(&current->sighand->siglock, flags);
3180 return tty;
3181}
3182EXPORT_SYMBOL_GPL(get_current_tty);
3183
3184void tty_default_fops(struct file_operations *fops)
3185{
3186 *fops = tty_fops;
3187}
3188
3189/*
3190 * Initialize the console device. This is called *early*, so
3191 * we can't necessarily depend on lots of kernel help here.
3192 * Just do some early initializations, and do the complex setup
3193 * later.
3194 */
3195void __init console_init(void)
3196{
3197 initcall_t *call;
3198
3199 /* Setup the default TTY line discipline. */
3200 tty_ldisc_begin();
3201
3202 /*
3203 * set up the console device so that later boot sequences can
3204 * inform about problems etc..
3205 */
3206 call = __con_initcall_start;
3207 while (call < __con_initcall_end) {
3208 (*call)();
3209 call++;
3210 }
3211}
3212
3213static char *tty_devnode(struct device *dev, mode_t *mode)
3214{
3215 if (!mode)
3216 return NULL;
3217 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3218 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3219 *mode = 0666;
3220 return NULL;
3221}
3222
3223static int __init tty_class_init(void)
3224{
3225 tty_class = class_create(THIS_MODULE, "tty");
3226 if (IS_ERR(tty_class))
3227 return PTR_ERR(tty_class);
3228 tty_class->devnode = tty_devnode;
3229 return 0;
3230}
3231
3232postcore_initcall(tty_class_init);
3233
3234/* 3/2004 jmc: why do these devices exist? */
3235
3236static struct cdev tty_cdev, console_cdev;
3237
3238/*
3239 * Ok, now we can initialize the rest of the tty devices and can count
3240 * on memory allocations, interrupts etc..
3241 */
3242int __init tty_init(void)
3243{
3244 cdev_init(&tty_cdev, &tty_fops);
3245 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3246 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3247 panic("Couldn't register /dev/tty driver\n");
3248 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3249 "tty");
3250
3251 cdev_init(&console_cdev, &console_fops);
3252 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3253 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3254 panic("Couldn't register /dev/console driver\n");
3255 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3256 "console");
3257
3258#ifdef CONFIG_VT
3259 vty_init(&console_fops);
3260#endif
3261 return 0;
3262}
3263
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-11 13:23:50 -0500