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[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / char / tty_io.c
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1da177e4
LT		 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 init_dev and 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() -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
66 */
67
68#include <linux/config.h>
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/console.h>
82#include <linux/timer.h>
83#include <linux/ctype.h>
84#include <linux/kd.h>
85#include <linux/mm.h>
86#include <linux/string.h>
87#include <linux/slab.h>
88#include <linux/poll.h>
89#include <linux/proc_fs.h>
90#include <linux/init.h>
91#include <linux/module.h>
92#include <linux/smp_lock.h>
93#include <linux/device.h>
94#include <linux/idr.h>
95#include <linux/wait.h>
96#include <linux/bitops.h>
b20f3ae5 97#include <linux/delay.h>
1da177e4
LT		 98
99#include <asm/uaccess.h>
100#include <asm/system.h>
101
102#include <linux/kbd_kern.h>
103#include <linux/vt_kern.h>
104#include <linux/selection.h>
105#include <linux/devfs_fs_kernel.h>
106
107#include <linux/kmod.h>
108
109#undef TTY_DEBUG_HANGUP
110
111#define TTY_PARANOIA_CHECK 1
112#define CHECK_TTY_COUNT 1
113
114struct termios tty_std_termios = { /* for the benefit of tty drivers */
115 .c_iflag = ICRNL | IXON,
116 .c_oflag = OPOST | ONLCR,
117 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
118 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
119 ECHOCTL | ECHOKE | IEXTEN,
120 .c_cc = INIT_C_CC
121};
122
123EXPORT_SYMBOL(tty_std_termios);
124
125/* This list gets poked at by procfs and various bits of boot up code. This
126 could do with some rationalisation such as pulling the tty proc function
127 into this file */
128
129LIST_HEAD(tty_drivers); /* linked list of tty drivers */
130
131/* Semaphore to protect creating and releasing a tty. This is shared with
132 vt.c for deeply disgusting hack reasons */
70522e12 133DEFINE_MUTEX(tty_mutex);
1da177e4
LT		 134
135#ifdef CONFIG_UNIX98_PTYS
136extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */
137extern int pty_limit; /* Config limit on Unix98 ptys */
138static DEFINE_IDR(allocated_ptys);
139static DECLARE_MUTEX(allocated_ptys_lock);
140static int ptmx_open(struct inode *, struct file *);
141#endif
142
143extern void disable_early_printk(void);
144
145static void initialize_tty_struct(struct tty_struct *tty);
146
147static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
148static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
149ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *);
150static unsigned int tty_poll(struct file *, poll_table *);
151static int tty_open(struct inode *, struct file *);
152static int tty_release(struct inode *, struct file *);
153int tty_ioctl(struct inode * inode, struct file * file,
154 unsigned int cmd, unsigned long arg);
155static int tty_fasync(int fd, struct file * filp, int on);
1da177e4
LT		 156static void release_mem(struct tty_struct *tty, int idx);
157
158
159static struct tty_struct *alloc_tty_struct(void)
160{
161 struct tty_struct *tty;
162
163 tty = kmalloc(sizeof(struct tty_struct), GFP_KERNEL);
164 if (tty)
165 memset(tty, 0, sizeof(struct tty_struct));
166 return tty;
167}
168
33f0f88f
AC		 169static void tty_buffer_free_all(struct tty_struct *);
170
1da177e4
LT		 171static inline void free_tty_struct(struct tty_struct *tty)
172{
173 kfree(tty->write_buf);
33f0f88f 174 tty_buffer_free_all(tty);
1da177e4
LT		 175 kfree(tty);
176}
177
178#define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
179
180char *tty_name(struct tty_struct *tty, char *buf)
181{
182 if (!tty) /* Hmm. NULL pointer. That's fun. */
183 strcpy(buf, "NULL tty");
184 else
185 strcpy(buf, tty->name);
186 return buf;
187}
188
189EXPORT_SYMBOL(tty_name);
190
d769a669 191int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
1da177e4
LT		 192 const char *routine)
193{
194#ifdef TTY_PARANOIA_CHECK
195 if (!tty) {
196 printk(KERN_WARNING
197 "null TTY for (%d:%d) in %s\n",
198 imajor(inode), iminor(inode), routine);
199 return 1;
200 }
201 if (tty->magic != TTY_MAGIC) {
202 printk(KERN_WARNING
203 "bad magic number for tty struct (%d:%d) in %s\n",
204 imajor(inode), iminor(inode), routine);
205 return 1;
206 }
207#endif
208 return 0;
209}
210
211static int check_tty_count(struct tty_struct *tty, const char *routine)
212{
213#ifdef CHECK_TTY_COUNT
214 struct list_head *p;
215 int count = 0;
216
217 file_list_lock();
218 list_for_each(p, &tty->tty_files) {
219 count++;
220 }
221 file_list_unlock();
222 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
223 tty->driver->subtype == PTY_TYPE_SLAVE &&
224 tty->link && tty->link->count)
225 count++;
226 if (tty->count != count) {
227 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
228 "!= #fd's(%d) in %s\n",
229 tty->name, tty->count, count, routine);
230 return count;
231 }
232#endif
233 return 0;
234}
235
33f0f88f
AC		 236/*
237 * Tty buffer allocation management
238 */
239
240static void tty_buffer_free_all(struct tty_struct *tty)
241{
242 struct tty_buffer *thead;
243 while((thead = tty->buf.head) != NULL) {
244 tty->buf.head = thead->next;
245 kfree(thead);
246 }
247 while((thead = tty->buf.free) != NULL) {
248 tty->buf.free = thead->next;
249 kfree(thead);
250 }
251 tty->buf.tail = NULL;
252}
253
254static void tty_buffer_init(struct tty_struct *tty)
255{
808249ce 256 spin_lock_init(&tty->buf.lock);
33f0f88f
AC		 257 tty->buf.head = NULL;
258 tty->buf.tail = NULL;
259 tty->buf.free = NULL;
260}
261
262static struct tty_buffer *tty_buffer_alloc(size_t size)
263{
264 struct tty_buffer *p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
265 if(p == NULL)
266 return NULL;
267 p->used = 0;
268 p->size = size;
269 p->next = NULL;
808249ce 270 p->active = 0;
8977d929
PF		 271 p->commit = 0;
272 p->read = 0;
33f0f88f
AC		 273 p->char_buf_ptr = (char *)(p->data);
274 p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
275/* printk("Flip create %p\n", p); */
276 return p;
277}
278
279/* Must be called with the tty_read lock held. This needs to acquire strategy
280 code to decide if we should kfree or relink a given expired buffer */
281
282static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
283{
284 /* Dumb strategy for now - should keep some stats */
285/* printk("Flip dispose %p\n", b); */
286 if(b->size >= 512)
287 kfree(b);
288 else {
289 b->next = tty->buf.free;
290 tty->buf.free = b;
291 }
292}
293
294static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
295{
296 struct tty_buffer **tbh = &tty->buf.free;
297 while((*tbh) != NULL) {
298 struct tty_buffer *t = *tbh;
299 if(t->size >= size) {
300 *tbh = t->next;
301 t->next = NULL;
302 t->used = 0;
8977d929
PF		 303 t->commit = 0;
304 t->read = 0;
33f0f88f 305 /* DEBUG ONLY */
6af6aab3 306/* memset(t->data, '*', size); */
33f0f88f
AC		 307/* printk("Flip recycle %p\n", t); */
308 return t;
309 }
310 tbh = &((*tbh)->next);
311 }
312 /* Round the buffer size out */
313 size = (size + 0xFF) & ~ 0xFF;
314 return tty_buffer_alloc(size);
315 /* Should possibly check if this fails for the largest buffer we
316 have queued and recycle that ? */
317}
318
319int tty_buffer_request_room(struct tty_struct *tty, size_t size)
320{
808249ce
PF		 321 struct tty_buffer *b, *n;
322 int left;
323 unsigned long flags;
324
325 spin_lock_irqsave(&tty->buf.lock, flags);
33f0f88f
AC		 326
327 /* OPTIMISATION: We could keep a per tty "zero" sized buffer to
328 remove this conditional if its worth it. This would be invisible
329 to the callers */
808249ce 330 if ((b = tty->buf.tail) != NULL) {
33f0f88f 331 left = b->size - b->used;
808249ce
PF		 332 b->active = 1;
333 } else
334 left = 0;
335
336 if (left < size) {
337 /* This is the slow path - looking for new buffers to use */
338 if ((n = tty_buffer_find(tty, size)) != NULL) {
339 if (b != NULL) {
340 b->next = n;
341 b->active = 0;
8977d929 342 b->commit = b->used;
808249ce
PF		 343 } else
344 tty->buf.head = n;
345 tty->buf.tail = n;
346 n->active = 1;
347 } else
348 size = left;
349 }
350
351 spin_unlock_irqrestore(&tty->buf.lock, flags);
33f0f88f
AC		 352 return size;
353}
33f0f88f
AC		 354EXPORT_SYMBOL_GPL(tty_buffer_request_room);
355
e1a25090
AM		 356int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars,
357 size_t size)
33f0f88f
AC		 358{
359 int copied = 0;
360 do {
361 int space = tty_buffer_request_room(tty, size - copied);
362 struct tty_buffer *tb = tty->buf.tail;
363 /* If there is no space then tb may be NULL */
364 if(unlikely(space == 0))
365 break;
366 memcpy(tb->char_buf_ptr + tb->used, chars, space);
367 memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
368 tb->used += space;
369 copied += space;
370 chars += space;
33f0f88f
AC		 371 }
372 /* There is a small chance that we need to split the data over
373 several buffers. If this is the case we must loop */
374 while (unlikely(size > copied));
375 return copied;
376}
ee37df78 377EXPORT_SYMBOL(tty_insert_flip_string);
33f0f88f 378
e1a25090
AM		 379int tty_insert_flip_string_flags(struct tty_struct *tty,
380 const unsigned char *chars, const char *flags, size_t size)
33f0f88f
AC		 381{
382 int copied = 0;
383 do {
384 int space = tty_buffer_request_room(tty, size - copied);
385 struct tty_buffer *tb = tty->buf.tail;
386 /* If there is no space then tb may be NULL */
387 if(unlikely(space == 0))
388 break;
389 memcpy(tb->char_buf_ptr + tb->used, chars, space);
390 memcpy(tb->flag_buf_ptr + tb->used, flags, space);
391 tb->used += space;
392 copied += space;
393 chars += space;
394 flags += space;
395 }
396 /* There is a small chance that we need to split the data over
397 several buffers. If this is the case we must loop */
398 while (unlikely(size > copied));
399 return copied;
400}
33f0f88f
AC		 401EXPORT_SYMBOL_GPL(tty_insert_flip_string_flags);
402
e1a25090
AM		 403void tty_schedule_flip(struct tty_struct *tty)
404{
405 unsigned long flags;
406 spin_lock_irqsave(&tty->buf.lock, flags);
407 if (tty->buf.tail != NULL) {
408 tty->buf.tail->active = 0;
409 tty->buf.tail->commit = tty->buf.tail->used;
410 }
411 spin_unlock_irqrestore(&tty->buf.lock, flags);
412 schedule_delayed_work(&tty->buf.work, 1);
413}
414EXPORT_SYMBOL(tty_schedule_flip);
33f0f88f
AC		 415
416/*
417 * Prepare a block of space in the buffer for data. Returns the length
418 * available and buffer pointer to the space which is now allocated and
419 * accounted for as ready for normal characters. This is used for drivers
420 * that need their own block copy routines into the buffer. There is no
421 * guarantee the buffer is a DMA target!
422 */
423
424int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size)
425{
426 int space = tty_buffer_request_room(tty, size);
808249ce
PF		 427 if (likely(space)) {
428 struct tty_buffer *tb = tty->buf.tail;
429 *chars = tb->char_buf_ptr + tb->used;
430 memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
431 tb->used += space;
432 }
33f0f88f
AC		 433 return space;
434}
435
436EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
437
438/*
439 * Prepare a block of space in the buffer for data. Returns the length
440 * available and buffer pointer to the space which is now allocated and
441 * accounted for as ready for characters. This is used for drivers
442 * that need their own block copy routines into the buffer. There is no
443 * guarantee the buffer is a DMA target!
444 */
445
446int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size)
447{
448 int space = tty_buffer_request_room(tty, size);
808249ce
PF		 449 if (likely(space)) {
450 struct tty_buffer *tb = tty->buf.tail;
451 *chars = tb->char_buf_ptr + tb->used;
452 *flags = tb->flag_buf_ptr + tb->used;
453 tb->used += space;
454 }
33f0f88f
AC		 455 return space;
456}
457
458EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
459
460
461
1da177e4
LT		 462/*
463 * This is probably overkill for real world processors but
464 * they are not on hot paths so a little discipline won't do
465 * any harm.
466 */
467
468static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
469{
470 down(&tty->termios_sem);
471 tty->termios->c_line = num;
472 up(&tty->termios_sem);
473}
474
475/*
476 * This guards the refcounted line discipline lists. The lock
477 * must be taken with irqs off because there are hangup path
478 * callers who will do ldisc lookups and cannot sleep.
479 */
480
481static DEFINE_SPINLOCK(tty_ldisc_lock);
482static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);
bfb07599 483static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */
1da177e4
LT		 484
485int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc)
486{
487 unsigned long flags;
488 int ret = 0;
489
490 if (disc < N_TTY || disc >= NR_LDISCS)
491 return -EINVAL;
492
493 spin_lock_irqsave(&tty_ldisc_lock, flags);
bfb07599
AD		 494 tty_ldiscs[disc] = *new_ldisc;
495 tty_ldiscs[disc].num = disc;
496 tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED;
497 tty_ldiscs[disc].refcount = 0;
1da177e4
LT		 498 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
499
500 return ret;
501}
1da177e4
LT		 502EXPORT_SYMBOL(tty_register_ldisc);
503
bfb07599
AD		 504int tty_unregister_ldisc(int disc)
505{
506 unsigned long flags;
507 int ret = 0;
508
509 if (disc < N_TTY || disc >= NR_LDISCS)
510 return -EINVAL;
511
512 spin_lock_irqsave(&tty_ldisc_lock, flags);
513 if (tty_ldiscs[disc].refcount)
514 ret = -EBUSY;
515 else
516 tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED;
517 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
518
519 return ret;
520}
521EXPORT_SYMBOL(tty_unregister_ldisc);
522
1da177e4
LT		 523struct tty_ldisc *tty_ldisc_get(int disc)
524{
525 unsigned long flags;
526 struct tty_ldisc *ld;
527
528 if (disc < N_TTY || disc >= NR_LDISCS)
529 return NULL;
530
531 spin_lock_irqsave(&tty_ldisc_lock, flags);
532
533 ld = &tty_ldiscs[disc];
534 /* Check the entry is defined */
535 if(ld->flags & LDISC_FLAG_DEFINED)
536 {
537 /* If the module is being unloaded we can't use it */
538 if (!try_module_get(ld->owner))
539 ld = NULL;
540 else /* lock it */
541 ld->refcount++;
542 }
543 else
544 ld = NULL;
545 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
546 return ld;
547}
548
549EXPORT_SYMBOL_GPL(tty_ldisc_get);
550
551void tty_ldisc_put(int disc)
552{
553 struct tty_ldisc *ld;
554 unsigned long flags;
555
56ee4827 556 BUG_ON(disc < N_TTY || disc >= NR_LDISCS);
1da177e4
LT		 557
558 spin_lock_irqsave(&tty_ldisc_lock, flags);
559 ld = &tty_ldiscs[disc];
56ee4827
ES		 560 BUG_ON(ld->refcount == 0);
561 ld->refcount--;
1da177e4
LT		 562 module_put(ld->owner);
563 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
564}
565
566EXPORT_SYMBOL_GPL(tty_ldisc_put);
567
568static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld)
569{
570 tty->ldisc = *ld;
571 tty->ldisc.refcount = 0;
572}
573
574/**
575 * tty_ldisc_try - internal helper
576 * @tty: the tty
577 *
578 * Make a single attempt to grab and bump the refcount on
579 * the tty ldisc. Return 0 on failure or 1 on success. This is
580 * used to implement both the waiting and non waiting versions
581 * of tty_ldisc_ref
582 */
583
584static int tty_ldisc_try(struct tty_struct *tty)
585{
586 unsigned long flags;
587 struct tty_ldisc *ld;
588 int ret = 0;
589
590 spin_lock_irqsave(&tty_ldisc_lock, flags);
591 ld = &tty->ldisc;
592 if(test_bit(TTY_LDISC, &tty->flags))
593 {
594 ld->refcount++;
595 ret = 1;
596 }
597 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
598 return ret;
599}
600
601/**
602 * tty_ldisc_ref_wait - wait for the tty ldisc
603 * @tty: tty device
604 *
605 * Dereference the line discipline for the terminal and take a
606 * reference to it. If the line discipline is in flux then
607 * wait patiently until it changes.
608 *
609 * Note: Must not be called from an IRQ/timer context. The caller
610 * must also be careful not to hold other locks that will deadlock
611 * against a discipline change, such as an existing ldisc reference
612 * (which we check for)
613 */
614
615struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)
616{
617 /* wait_event is a macro */
618 wait_event(tty_ldisc_wait, tty_ldisc_try(tty));
619 if(tty->ldisc.refcount == 0)
620 printk(KERN_ERR "tty_ldisc_ref_wait\n");
621 return &tty->ldisc;
622}
623
624EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait);
625
626/**
627 * tty_ldisc_ref - get the tty ldisc
628 * @tty: tty device
629 *
630 * Dereference the line discipline for the terminal and take a
631 * reference to it. If the line discipline is in flux then
632 * return NULL. Can be called from IRQ and timer functions.
633 */
634
635struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty)
636{
637 if(tty_ldisc_try(tty))
638 return &tty->ldisc;
639 return NULL;
640}
641
642EXPORT_SYMBOL_GPL(tty_ldisc_ref);
643
644/**
645 * tty_ldisc_deref - free a tty ldisc reference
646 * @ld: reference to free up
647 *
648 * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May
649 * be called in IRQ context.
650 */
651
652void tty_ldisc_deref(struct tty_ldisc *ld)
653{
654 unsigned long flags;
655
56ee4827 656 BUG_ON(ld == NULL);
1da177e4
LT		 657
658 spin_lock_irqsave(&tty_ldisc_lock, flags);
659 if(ld->refcount == 0)
660 printk(KERN_ERR "tty_ldisc_deref: no references.\n");
661 else
662 ld->refcount--;
663 if(ld->refcount == 0)
664 wake_up(&tty_ldisc_wait);
665 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
666}
667
668EXPORT_SYMBOL_GPL(tty_ldisc_deref);
669
670/**
671 * tty_ldisc_enable - allow ldisc use
672 * @tty: terminal to activate ldisc on
673 *
674 * Set the TTY_LDISC flag when the line discipline can be called
675 * again. Do neccessary wakeups for existing sleepers.
676 *
677 * Note: nobody should set this bit except via this function. Clearing
678 * directly is allowed.
679 */
680
681static void tty_ldisc_enable(struct tty_struct *tty)
682{
683 set_bit(TTY_LDISC, &tty->flags);
684 wake_up(&tty_ldisc_wait);
685}
686
687/**
688 * tty_set_ldisc - set line discipline
689 * @tty: the terminal to set
690 * @ldisc: the line discipline
691 *
692 * Set the discipline of a tty line. Must be called from a process
693 * context.
694 */
695
696static int tty_set_ldisc(struct tty_struct *tty, int ldisc)
697{
ff55fe20
JB		 698 int retval = 0;
699 struct tty_ldisc o_ldisc;
1da177e4
LT		 700 char buf[64];
701 int work;
702 unsigned long flags;
703 struct tty_ldisc *ld;
ff55fe20 704 struct tty_struct *o_tty;
1da177e4
LT		 705
706 if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS))
707 return -EINVAL;
708
709restart:
710
1da177e4
LT		 711 ld = tty_ldisc_get(ldisc);
712 /* Eduardo Blanco <ejbs@cs.cs.com.uy> */
713 /* Cyrus Durgin <cider@speakeasy.org> */
714 if (ld == NULL) {
715 request_module("tty-ldisc-%d", ldisc);
716 ld = tty_ldisc_get(ldisc);
717 }
718 if (ld == NULL)
719 return -EINVAL;
720
33f0f88f
AC		 721 /*
722 * No more input please, we are switching. The new ldisc
723 * will update this value in the ldisc open function
724 */
725
726 tty->receive_room = 0;
727
728 /*
729 * Problem: What do we do if this blocks ?
730 */
731
1da177e4
LT		 732 tty_wait_until_sent(tty, 0);
733
ff55fe20
JB		 734 if (tty->ldisc.num == ldisc) {
735 tty_ldisc_put(ldisc);
736 return 0;
737 }
738
739 o_ldisc = tty->ldisc;
740 o_tty = tty->link;
741
1da177e4
LT		 742 /*
743 * Make sure we don't change while someone holds a
744 * reference to the line discipline. The TTY_LDISC bit
745 * prevents anyone taking a reference once it is clear.
746 * We need the lock to avoid racing reference takers.
747 */
ff55fe20 748
1da177e4 749 spin_lock_irqsave(&tty_ldisc_lock, flags);
ff55fe20
JB		 750 if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) {
751 if(tty->ldisc.refcount) {
752 /* Free the new ldisc we grabbed. Must drop the lock
753 first. */
754 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
755 tty_ldisc_put(ldisc);
756 /*
757 * There are several reasons we may be busy, including
758 * random momentary I/O traffic. We must therefore
759 * retry. We could distinguish between blocking ops
760 * and retries if we made tty_ldisc_wait() smarter. That
761 * is up for discussion.
762 */
763 if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0)
764 return -ERESTARTSYS;
765 goto restart;
766 }
767 if(o_tty && o_tty->ldisc.refcount) {
768 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
769 tty_ldisc_put(ldisc);
770 if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0)
771 return -ERESTARTSYS;
772 goto restart;
773 }
774 }
775
776 /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */
777
778 if (!test_bit(TTY_LDISC, &tty->flags)) {
1da177e4
LT		 779 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
780 tty_ldisc_put(ldisc);
ff55fe20
JB		 781 ld = tty_ldisc_ref_wait(tty);
782 tty_ldisc_deref(ld);
1da177e4
LT		 783 goto restart;
784 }
ff55fe20
JB		 785
786 clear_bit(TTY_LDISC, &tty->flags);
1da177e4 787 clear_bit(TTY_DONT_FLIP, &tty->flags);
ff55fe20
JB		 788 if (o_tty) {
789 clear_bit(TTY_LDISC, &o_tty->flags);
790 clear_bit(TTY_DONT_FLIP, &o_tty->flags);
791 }
1da177e4 792 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
ff55fe20 793
1da177e4
LT		 794 /*
795 * From this point on we know nobody has an ldisc
796 * usage reference, nor can they obtain one until
797 * we say so later on.
798 */
ff55fe20 799
33f0f88f 800 work = cancel_delayed_work(&tty->buf.work);
1da177e4 801 /*
33f0f88f 802 * Wait for ->hangup_work and ->buf.work handlers to terminate
1da177e4
LT		 803 */
804
805 flush_scheduled_work();
806 /* Shutdown the current discipline. */
807 if (tty->ldisc.close)
808 (tty->ldisc.close)(tty);
809
810 /* Now set up the new line discipline. */
811 tty_ldisc_assign(tty, ld);
812 tty_set_termios_ldisc(tty, ldisc);
813 if (tty->ldisc.open)
814 retval = (tty->ldisc.open)(tty);
815 if (retval < 0) {
816 tty_ldisc_put(ldisc);
817 /* There is an outstanding reference here so this is safe */
818 tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num));
819 tty_set_termios_ldisc(tty, tty->ldisc.num);
820 if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) {
821 tty_ldisc_put(o_ldisc.num);
822 /* This driver is always present */
823 tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
824 tty_set_termios_ldisc(tty, N_TTY);
825 if (tty->ldisc.open) {
826 int r = tty->ldisc.open(tty);
827
828 if (r < 0)
829 panic("Couldn't open N_TTY ldisc for "
830 "%s --- error %d.",
831 tty_name(tty, buf), r);
832 }
833 }
834 }
835 /* At this point we hold a reference to the new ldisc and a
836 a reference to the old ldisc. If we ended up flipping back
837 to the existing ldisc we have two references to it */
838
839 if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc)
840 tty->driver->set_ldisc(tty);
841
842 tty_ldisc_put(o_ldisc.num);
843
844 /*
845 * Allow ldisc referencing to occur as soon as the driver
846 * ldisc callback completes.
847 */
848
849 tty_ldisc_enable(tty);
ff55fe20
JB		 850 if (o_tty)
851 tty_ldisc_enable(o_tty);
1da177e4
LT		 852
853 /* Restart it in case no characters kick it off. Safe if
854 already running */
ff55fe20 855 if (work)
33f0f88f 856 schedule_delayed_work(&tty->buf.work, 1);
1da177e4
LT		 857 return retval;
858}
859
860/*
861 * This routine returns a tty driver structure, given a device number
862 */
863static struct tty_driver *get_tty_driver(dev_t device, int *index)
864{
865 struct tty_driver *p;
866
867 list_for_each_entry(p, &tty_drivers, tty_drivers) {
868 dev_t base = MKDEV(p->major, p->minor_start);
869 if (device < base || device >= base + p->num)
870 continue;
871 *index = device - base;
872 return p;
873 }
874 return NULL;
875}
876
877/*
878 * If we try to write to, or set the state of, a terminal and we're
879 * not in the foreground, send a SIGTTOU. If the signal is blocked or
880 * ignored, go ahead and perform the operation. (POSIX 7.2)
881 */
882int tty_check_change(struct tty_struct * tty)
883{
884 if (current->signal->tty != tty)
885 return 0;
886 if (tty->pgrp <= 0) {
887 printk(KERN_WARNING "tty_check_change: tty->pgrp <= 0!\n");
888 return 0;
889 }
890 if (process_group(current) == tty->pgrp)
891 return 0;
892 if (is_ignored(SIGTTOU))
893 return 0;
894 if (is_orphaned_pgrp(process_group(current)))
895 return -EIO;
896 (void) kill_pg(process_group(current), SIGTTOU, 1);
897 return -ERESTARTSYS;
898}
899
900EXPORT_SYMBOL(tty_check_change);
901
902static ssize_t hung_up_tty_read(struct file * file, char __user * buf,
903 size_t count, loff_t *ppos)
904{
905 return 0;
906}
907
908static ssize_t hung_up_tty_write(struct file * file, const char __user * buf,
909 size_t count, loff_t *ppos)
910{
911 return -EIO;
912}
913
914/* No kernel lock held - none needed ;) */
915static unsigned int hung_up_tty_poll(struct file * filp, poll_table * wait)
916{
917 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
918}
919
920static int hung_up_tty_ioctl(struct inode * inode, struct file * file,
921 unsigned int cmd, unsigned long arg)
922{
923 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
924}
925
926static struct file_operations tty_fops = {
927 .llseek = no_llseek,
928 .read = tty_read,
929 .write = tty_write,
930 .poll = tty_poll,
931 .ioctl = tty_ioctl,
932 .open = tty_open,
933 .release = tty_release,
934 .fasync = tty_fasync,
935};
936
937#ifdef CONFIG_UNIX98_PTYS
938static struct file_operations ptmx_fops = {
939 .llseek = no_llseek,
940 .read = tty_read,
941 .write = tty_write,
942 .poll = tty_poll,
943 .ioctl = tty_ioctl,
944 .open = ptmx_open,
945 .release = tty_release,
946 .fasync = tty_fasync,
947};
948#endif
949
950static struct file_operations console_fops = {
951 .llseek = no_llseek,
952 .read = tty_read,
953 .write = redirected_tty_write,
954 .poll = tty_poll,
955 .ioctl = tty_ioctl,
956 .open = tty_open,
957 .release = tty_release,
958 .fasync = tty_fasync,
959};
960
961static struct file_operations hung_up_tty_fops = {
962 .llseek = no_llseek,
963 .read = hung_up_tty_read,
964 .write = hung_up_tty_write,
965 .poll = hung_up_tty_poll,
966 .ioctl = hung_up_tty_ioctl,
967 .release = tty_release,
968};
969
970static DEFINE_SPINLOCK(redirect_lock);
971static struct file *redirect;
972
973/**
974 * tty_wakeup - request more data
975 * @tty: terminal
976 *
977 * Internal and external helper for wakeups of tty. This function
978 * informs the line discipline if present that the driver is ready
979 * to receive more output data.
980 */
981
982void tty_wakeup(struct tty_struct *tty)
983{
984 struct tty_ldisc *ld;
985
986 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
987 ld = tty_ldisc_ref(tty);
988 if(ld) {
989 if(ld->write_wakeup)
990 ld->write_wakeup(tty);
991 tty_ldisc_deref(ld);
992 }
993 }
994 wake_up_interruptible(&tty->write_wait);
995}
996
997EXPORT_SYMBOL_GPL(tty_wakeup);
998
999/**
1000 * tty_ldisc_flush - flush line discipline queue
1001 * @tty: tty
1002 *
1003 * Flush the line discipline queue (if any) for this tty. If there
1004 * is no line discipline active this is a no-op.
1005 */
1006
1007void tty_ldisc_flush(struct tty_struct *tty)
1008{
1009 struct tty_ldisc *ld = tty_ldisc_ref(tty);
1010 if(ld) {
1011 if(ld->flush_buffer)
1012 ld->flush_buffer(tty);
1013 tty_ldisc_deref(ld);
1014 }
1015}
1016
1017EXPORT_SYMBOL_GPL(tty_ldisc_flush);
1018
1019/*
1020 * This can be called by the "eventd" kernel thread. That is process synchronous,
1021 * but doesn't hold any locks, so we need to make sure we have the appropriate
1022 * locks for what we're doing..
1023 */
1024static void do_tty_hangup(void *data)
1025{
1026 struct tty_struct *tty = (struct tty_struct *) data;
1027 struct file * cons_filp = NULL;
1028 struct file *filp, *f = NULL;
1029 struct task_struct *p;
1030 struct tty_ldisc *ld;
1031 int closecount = 0, n;
1032
1033 if (!tty)
1034 return;
1035
1036 /* inuse_filps is protected by the single kernel lock */
1037 lock_kernel();
1038
1039 spin_lock(&redirect_lock);
1040 if (redirect && redirect->private_data == tty) {
1041 f = redirect;
1042 redirect = NULL;
1043 }
1044 spin_unlock(&redirect_lock);
1045
1046 check_tty_count(tty, "do_tty_hangup");
1047 file_list_lock();
1048 /* This breaks for file handles being sent over AF_UNIX sockets ? */
2f512016 1049 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
1da177e4
LT		 1050 if (filp->f_op->write == redirected_tty_write)
1051 cons_filp = filp;
1052 if (filp->f_op->write != tty_write)
1053 continue;
1054 closecount++;
1055 tty_fasync(-1, filp, 0); /* can't block */
1056 filp->f_op = &hung_up_tty_fops;
1057 }
1058 file_list_unlock();
1059
1060 /* FIXME! What are the locking issues here? This may me overdoing things..
1061 * this question is especially important now that we've removed the irqlock. */
1062
1063 ld = tty_ldisc_ref(tty);
1064 if(ld != NULL) /* We may have no line discipline at this point */
1065 {
1066 if (ld->flush_buffer)
1067 ld->flush_buffer(tty);
1068 if (tty->driver->flush_buffer)
1069 tty->driver->flush_buffer(tty);
1070 if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&
1071 ld->write_wakeup)
1072 ld->write_wakeup(tty);
1073 if (ld->hangup)
1074 ld->hangup(tty);
1075 }
1076
1077 /* FIXME: Once we trust the LDISC code better we can wait here for
1078 ldisc completion and fix the driver call race */
1079
1080 wake_up_interruptible(&tty->write_wait);
1081 wake_up_interruptible(&tty->read_wait);
1082
1083 /*
1084 * Shutdown the current line discipline, and reset it to
1085 * N_TTY.
1086 */
1087 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1088 {
1089 down(&tty->termios_sem);
1090 *tty->termios = tty->driver->init_termios;
1091 up(&tty->termios_sem);
1092 }
1093
1094 /* Defer ldisc switch */
1095 /* tty_deferred_ldisc_switch(N_TTY);
1096
1097 This should get done automatically when the port closes and
1098 tty_release is called */
1099
1100 read_lock(&tasklist_lock);
1101 if (tty->session > 0) {
1102 do_each_task_pid(tty->session, PIDTYPE_SID, p) {
1103 if (p->signal->tty == tty)
1104 p->signal->tty = NULL;
1105 if (!p->signal->leader)
1106 continue;
f96a795d
EB		 1107 group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
1108 group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
1da177e4
LT		 1109 if (tty->pgrp > 0)
1110 p->signal->tty_old_pgrp = tty->pgrp;
1111 } while_each_task_pid(tty->session, PIDTYPE_SID, p);
1112 }
1113 read_unlock(&tasklist_lock);
1114
1115 tty->flags = 0;
1116 tty->session = 0;
1117 tty->pgrp = -1;
1118 tty->ctrl_status = 0;
1119 /*
1120 * If one of the devices matches a console pointer, we
1121 * cannot just call hangup() because that will cause
1122 * tty->count and state->count to go out of sync.
1123 * So we just call close() the right number of times.
1124 */
1125 if (cons_filp) {
1126 if (tty->driver->close)
1127 for (n = 0; n < closecount; n++)
1128 tty->driver->close(tty, cons_filp);
1129 } else if (tty->driver->hangup)
1130 (tty->driver->hangup)(tty);
1131
1132 /* We don't want to have driver/ldisc interactions beyond
1133 the ones we did here. The driver layer expects no
1134 calls after ->hangup() from the ldisc side. However we
1135 can't yet guarantee all that */
1136
1137 set_bit(TTY_HUPPED, &tty->flags);
1138 if (ld) {
1139 tty_ldisc_enable(tty);
1140 tty_ldisc_deref(ld);
1141 }
1142 unlock_kernel();
1143 if (f)
1144 fput(f);
1145}
1146
1147void tty_hangup(struct tty_struct * tty)
1148{
1149#ifdef TTY_DEBUG_HANGUP
1150 char buf[64];
1151
1152 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
1153#endif
1154 schedule_work(&tty->hangup_work);
1155}
1156
1157EXPORT_SYMBOL(tty_hangup);
1158
1159void tty_vhangup(struct tty_struct * tty)
1160{
1161#ifdef TTY_DEBUG_HANGUP
1162 char buf[64];
1163
1164 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
1165#endif
1166 do_tty_hangup((void *) tty);
1167}
1168EXPORT_SYMBOL(tty_vhangup);
1169
1170int tty_hung_up_p(struct file * filp)
1171{
1172 return (filp->f_op == &hung_up_tty_fops);
1173}
1174
1175EXPORT_SYMBOL(tty_hung_up_p);
1176
1177/*
1178 * This function is typically called only by the session leader, when
1179 * it wants to disassociate itself from its controlling tty.
1180 *
1181 * It performs the following functions:
1182 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
1183 * (2) Clears the tty from being controlling the session
1184 * (3) Clears the controlling tty for all processes in the
1185 * session group.
1186 *
1187 * The argument on_exit is set to 1 if called when a process is
1188 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
1189 */
1190void disassociate_ctty(int on_exit)
1191{
1192 struct tty_struct *tty;
1193 struct task_struct *p;
1194 int tty_pgrp = -1;
1195
1196 lock_kernel();
1197
70522e12 1198 mutex_lock(&tty_mutex);
1da177e4
LT		 1199 tty = current->signal->tty;
1200 if (tty) {
1201 tty_pgrp = tty->pgrp;
70522e12 1202 mutex_unlock(&tty_mutex);
1da177e4
LT		 1203 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
1204 tty_vhangup(tty);
1205 } else {
1206 if (current->signal->tty_old_pgrp) {
1207 kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit);
1208 kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit);
1209 }
70522e12 1210 mutex_unlock(&tty_mutex);
1da177e4
LT		 1211 unlock_kernel();
1212 return;
1213 }
1214 if (tty_pgrp > 0) {
1215 kill_pg(tty_pgrp, SIGHUP, on_exit);
1216 if (!on_exit)
1217 kill_pg(tty_pgrp, SIGCONT, on_exit);
1218 }
1219
1220 /* Must lock changes to tty_old_pgrp */
70522e12 1221 mutex_lock(&tty_mutex);
1da177e4
LT		 1222 current->signal->tty_old_pgrp = 0;
1223 tty->session = 0;
1224 tty->pgrp = -1;
1225
1226 /* Now clear signal->tty under the lock */
1227 read_lock(&tasklist_lock);
1228 do_each_task_pid(current->signal->session, PIDTYPE_SID, p) {
1229 p->signal->tty = NULL;
1230 } while_each_task_pid(current->signal->session, PIDTYPE_SID, p);
1231 read_unlock(&tasklist_lock);
70522e12 1232 mutex_unlock(&tty_mutex);
1da177e4
LT		 1233 unlock_kernel();
1234}
1235
1236void stop_tty(struct tty_struct *tty)
1237{
1238 if (tty->stopped)
1239 return;
1240 tty->stopped = 1;
1241 if (tty->link && tty->link->packet) {
1242 tty->ctrl_status &= ~TIOCPKT_START;
1243 tty->ctrl_status |= TIOCPKT_STOP;
1244 wake_up_interruptible(&tty->link->read_wait);
1245 }
1246 if (tty->driver->stop)
1247 (tty->driver->stop)(tty);
1248}
1249
1250EXPORT_SYMBOL(stop_tty);
1251
1252void start_tty(struct tty_struct *tty)
1253{
1254 if (!tty->stopped || tty->flow_stopped)
1255 return;
1256 tty->stopped = 0;
1257 if (tty->link && tty->link->packet) {
1258 tty->ctrl_status &= ~TIOCPKT_STOP;
1259 tty->ctrl_status |= TIOCPKT_START;
1260 wake_up_interruptible(&tty->link->read_wait);
1261 }
1262 if (tty->driver->start)
1263 (tty->driver->start)(tty);
1264
1265 /* If we have a running line discipline it may need kicking */
1266 tty_wakeup(tty);
1267 wake_up_interruptible(&tty->write_wait);
1268}
1269
1270EXPORT_SYMBOL(start_tty);
1271
1272static ssize_t tty_read(struct file * file, char __user * buf, size_t count,
1273 loff_t *ppos)
1274{
1275 int i;
1276 struct tty_struct * tty;
1277 struct inode *inode;
1278 struct tty_ldisc *ld;
1279
1280 tty = (struct tty_struct *)file->private_data;
1281 inode = file->f_dentry->d_inode;
1282 if (tty_paranoia_check(tty, inode, "tty_read"))
1283 return -EIO;
1284 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
1285 return -EIO;
1286
1287 /* We want to wait for the line discipline to sort out in this
1288 situation */
1289 ld = tty_ldisc_ref_wait(tty);
1290 lock_kernel();
1291 if (ld->read)
1292 i = (ld->read)(tty,file,buf,count);
1293 else
1294 i = -EIO;
1295 tty_ldisc_deref(ld);
1296 unlock_kernel();
1297 if (i > 0)
1298 inode->i_atime = current_fs_time(inode->i_sb);
1299 return i;
1300}
1301
1302/*
1303 * Split writes up in sane blocksizes to avoid
1304 * denial-of-service type attacks
1305 */
1306static inline ssize_t do_tty_write(
1307 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1308 struct tty_struct *tty,
1309 struct file *file,
1310 const char __user *buf,
1311 size_t count)
1312{
1313 ssize_t ret = 0, written = 0;
1314 unsigned int chunk;
1315
70522e12 1316 if (mutex_lock_interruptible(&tty->atomic_write_lock)) {
1da177e4
LT		 1317 return -ERESTARTSYS;
1318 }
1319
1320 /*
1321 * We chunk up writes into a temporary buffer. This
1322 * simplifies low-level drivers immensely, since they
1323 * don't have locking issues and user mode accesses.
1324 *
1325 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1326 * big chunk-size..
1327 *
1328 * The default chunk-size is 2kB, because the NTTY
1329 * layer has problems with bigger chunks. It will
1330 * claim to be able to handle more characters than
1331 * it actually does.
1332 */
1333 chunk = 2048;
1334 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1335 chunk = 65536;
1336 if (count < chunk)
1337 chunk = count;
1338
70522e12 1339 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1da177e4
LT		 1340 if (tty->write_cnt < chunk) {
1341 unsigned char *buf;
1342
1343 if (chunk < 1024)
1344 chunk = 1024;
1345
1346 buf = kmalloc(chunk, GFP_KERNEL);
1347 if (!buf) {
70522e12 1348 mutex_unlock(&tty->atomic_write_lock);
1da177e4
LT		 1349 return -ENOMEM;
1350 }
1351 kfree(tty->write_buf);
1352 tty->write_cnt = chunk;
1353 tty->write_buf = buf;
1354 }
1355
1356 /* Do the write .. */
1357 for (;;) {
1358 size_t size = count;
1359 if (size > chunk)
1360 size = chunk;
1361 ret = -EFAULT;
1362 if (copy_from_user(tty->write_buf, buf, size))
1363 break;
1364 lock_kernel();
1365 ret = write(tty, file, tty->write_buf, size);
1366 unlock_kernel();
1367 if (ret <= 0)
1368 break;
1369 written += ret;
1370 buf += ret;
1371 count -= ret;
1372 if (!count)
1373 break;
1374 ret = -ERESTARTSYS;
1375 if (signal_pending(current))
1376 break;
1377 cond_resched();
1378 }
1379 if (written) {
1380 struct inode *inode = file->f_dentry->d_inode;
1381 inode->i_mtime = current_fs_time(inode->i_sb);
1382 ret = written;
1383 }
70522e12 1384 mutex_unlock(&tty->atomic_write_lock);
1da177e4
LT		 1385 return ret;
1386}
1387
1388
1389static ssize_t tty_write(struct file * file, const char __user * buf, size_t count,
1390 loff_t *ppos)
1391{
1392 struct tty_struct * tty;
1393 struct inode *inode = file->f_dentry->d_inode;
1394 ssize_t ret;
1395 struct tty_ldisc *ld;
1396
1397 tty = (struct tty_struct *)file->private_data;
1398 if (tty_paranoia_check(tty, inode, "tty_write"))
1399 return -EIO;
1400 if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags)))
1401 return -EIO;
1402
1403 ld = tty_ldisc_ref_wait(tty);
1404 if (!ld->write)
1405 ret = -EIO;
1406 else
1407 ret = do_tty_write(ld->write, tty, file, buf, count);
1408 tty_ldisc_deref(ld);
1409 return ret;
1410}
1411
1412ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count,
1413 loff_t *ppos)
1414{
1415 struct file *p = NULL;
1416
1417 spin_lock(&redirect_lock);
1418 if (redirect) {
1419 get_file(redirect);
1420 p = redirect;
1421 }
1422 spin_unlock(&redirect_lock);
1423
1424 if (p) {
1425 ssize_t res;
1426 res = vfs_write(p, buf, count, &p->f_pos);
1427 fput(p);
1428 return res;
1429 }
1430
1431 return tty_write(file, buf, count, ppos);
1432}
1433
1434static char ptychar[] = "pqrstuvwxyzabcde";
1435
1436static inline void pty_line_name(struct tty_driver *driver, int index, char *p)
1437{
1438 int i = index + driver->name_base;
1439 /* ->name is initialized to "ttyp", but "tty" is expected */
1440 sprintf(p, "%s%c%x",
1441 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1442 ptychar[i >> 4 & 0xf], i & 0xf);
1443}
1444
1445static inline void tty_line_name(struct tty_driver *driver, int index, char *p)
1446{
1447 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1448}
1449
1450/*
1451 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
70522e12
IM		 1452 * failed open. The new code protects the open with a mutex, so it's
1453 * really quite straightforward. The mutex locking can probably be
1da177e4
LT		 1454 * relaxed for the (most common) case of reopening a tty.
1455 */
1456static int init_dev(struct tty_driver *driver, int idx,
1457 struct tty_struct **ret_tty)
1458{
1459 struct tty_struct *tty, *o_tty;
1460 struct termios *tp, **tp_loc, *o_tp, **o_tp_loc;
1461 struct termios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc;
1462 int retval=0;
1463
1464 /* check whether we're reopening an existing tty */
1465 if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1466 tty = devpts_get_tty(idx);
1467 if (tty && driver->subtype == PTY_TYPE_MASTER)
1468 tty = tty->link;
1469 } else {
1470 tty = driver->ttys[idx];
1471 }
1472 if (tty) goto fast_track;
1473
1474 /*
1475 * First time open is complex, especially for PTY devices.
1476 * This code guarantees that either everything succeeds and the
1477 * TTY is ready for operation, or else the table slots are vacated
1478 * and the allocated memory released. (Except that the termios
1479 * and locked termios may be retained.)
1480 */
1481
1482 if (!try_module_get(driver->owner)) {
1483 retval = -ENODEV;
1484 goto end_init;
1485 }
1486
1487 o_tty = NULL;
1488 tp = o_tp = NULL;
1489 ltp = o_ltp = NULL;
1490
1491 tty = alloc_tty_struct();
1492 if(!tty)
1493 goto fail_no_mem;
1494 initialize_tty_struct(tty);
1495 tty->driver = driver;
1496 tty->index = idx;
1497 tty_line_name(driver, idx, tty->name);
1498
1499 if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1500 tp_loc = &tty->termios;
1501 ltp_loc = &tty->termios_locked;
1502 } else {
1503 tp_loc = &driver->termios[idx];
1504 ltp_loc = &driver->termios_locked[idx];
1505 }
1506
1507 if (!*tp_loc) {
1508 tp = (struct termios *) kmalloc(sizeof(struct termios),
1509 GFP_KERNEL);
1510 if (!tp)
1511 goto free_mem_out;
1512 *tp = driver->init_termios;
1513 }
1514
1515 if (!*ltp_loc) {
1516 ltp = (struct termios *) kmalloc(sizeof(struct termios),
1517 GFP_KERNEL);
1518 if (!ltp)
1519 goto free_mem_out;
1520 memset(ltp, 0, sizeof(struct termios));
1521 }
1522
1523 if (driver->type == TTY_DRIVER_TYPE_PTY) {
1524 o_tty = alloc_tty_struct();
1525 if (!o_tty)
1526 goto free_mem_out;
1527 initialize_tty_struct(o_tty);
1528 o_tty->driver = driver->other;
1529 o_tty->index = idx;
1530 tty_line_name(driver->other, idx, o_tty->name);
1531
1532 if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
1533 o_tp_loc = &o_tty->termios;
1534 o_ltp_loc = &o_tty->termios_locked;
1535 } else {
1536 o_tp_loc = &driver->other->termios[idx];
1537 o_ltp_loc = &driver->other->termios_locked[idx];
1538 }
1539
1540 if (!*o_tp_loc) {
1541 o_tp = (struct termios *)
1542 kmalloc(sizeof(struct termios), GFP_KERNEL);
1543 if (!o_tp)
1544 goto free_mem_out;
1545 *o_tp = driver->other->init_termios;
1546 }
1547
1548 if (!*o_ltp_loc) {
1549 o_ltp = (struct termios *)
1550 kmalloc(sizeof(struct termios), GFP_KERNEL);
1551 if (!o_ltp)
1552 goto free_mem_out;
1553 memset(o_ltp, 0, sizeof(struct termios));
1554 }
1555
1556 /*
1557 * Everything allocated ... set up the o_tty structure.
1558 */
1559 if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) {
1560 driver->other->ttys[idx] = o_tty;
1561 }
1562 if (!*o_tp_loc)
1563 *o_tp_loc = o_tp;
1564 if (!*o_ltp_loc)
1565 *o_ltp_loc = o_ltp;
1566 o_tty->termios = *o_tp_loc;
1567 o_tty->termios_locked = *o_ltp_loc;
1568 driver->other->refcount++;
1569 if (driver->subtype == PTY_TYPE_MASTER)
1570 o_tty->count++;
1571
1572 /* Establish the links in both directions */
1573 tty->link = o_tty;
1574 o_tty->link = tty;
1575 }
1576
1577 /*
1578 * All structures have been allocated, so now we install them.
1579 * Failures after this point use release_mem to clean up, so
1580 * there's no need to null out the local pointers.
1581 */
1582 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1583 driver->ttys[idx] = tty;
1584 }
1585
1586 if (!*tp_loc)
1587 *tp_loc = tp;
1588 if (!*ltp_loc)
1589 *ltp_loc = ltp;
1590 tty->termios = *tp_loc;
1591 tty->termios_locked = *ltp_loc;
1592 driver->refcount++;
1593 tty->count++;
1594
1595 /*
1596 * Structures all installed ... call the ldisc open routines.
1597 * If we fail here just call release_mem to clean up. No need
1598 * to decrement the use counts, as release_mem doesn't care.
1599 */
1600
1601 if (tty->ldisc.open) {
1602 retval = (tty->ldisc.open)(tty);
1603 if (retval)
1604 goto release_mem_out;
1605 }
1606 if (o_tty && o_tty->ldisc.open) {
1607 retval = (o_tty->ldisc.open)(o_tty);
1608 if (retval) {
1609 if (tty->ldisc.close)
1610 (tty->ldisc.close)(tty);
1611 goto release_mem_out;
1612 }
1613 tty_ldisc_enable(o_tty);
1614 }
1615 tty_ldisc_enable(tty);
1616 goto success;
1617
1618 /*
1619 * This fast open can be used if the tty is already open.
1620 * No memory is allocated, and the only failures are from
1621 * attempting to open a closing tty or attempting multiple
1622 * opens on a pty master.
1623 */
1624fast_track:
1625 if (test_bit(TTY_CLOSING, &tty->flags)) {
1626 retval = -EIO;
1627 goto end_init;
1628 }
1629 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1630 driver->subtype == PTY_TYPE_MASTER) {
1631 /*
1632 * special case for PTY masters: only one open permitted,
1633 * and the slave side open count is incremented as well.
1634 */
1635 if (tty->count) {
1636 retval = -EIO;
1637 goto end_init;
1638 }
1639 tty->link->count++;
1640 }
1641 tty->count++;
1642 tty->driver = driver; /* N.B. why do this every time?? */
1643
1644 /* FIXME */
1645 if(!test_bit(TTY_LDISC, &tty->flags))
1646 printk(KERN_ERR "init_dev but no ldisc\n");
1647success:
1648 *ret_tty = tty;
1649
70522e12 1650 /* All paths come through here to release the mutex */
1da177e4
LT		 1651end_init:
1652 return retval;
1653
1654 /* Release locally allocated memory ... nothing placed in slots */
1655free_mem_out:
735d5661 1656 kfree(o_tp);
1da177e4
LT		 1657 if (o_tty)
1658 free_tty_struct(o_tty);
735d5661
JJ		 1659 kfree(ltp);
1660 kfree(tp);
1da177e4
LT		 1661 free_tty_struct(tty);
1662
1663fail_no_mem:
1664 module_put(driver->owner);
1665 retval = -ENOMEM;
1666 goto end_init;
1667
1668 /* call the tty release_mem routine to clean out this slot */
1669release_mem_out:
1670 printk(KERN_INFO "init_dev: ldisc open failed, "
1671 "clearing slot %d\n", idx);
1672 release_mem(tty, idx);
1673 goto end_init;
1674}
1675
1676/*
1677 * Releases memory associated with a tty structure, and clears out the
1678 * driver table slots.
1679 */
1680static void release_mem(struct tty_struct *tty, int idx)
1681{
1682 struct tty_struct *o_tty;
1683 struct termios *tp;
1684 int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM;
1685
1686 if ((o_tty = tty->link) != NULL) {
1687 if (!devpts)
1688 o_tty->driver->ttys[idx] = NULL;
1689 if (o_tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1690 tp = o_tty->termios;
1691 if (!devpts)
1692 o_tty->driver->termios[idx] = NULL;
1693 kfree(tp);
1694
1695 tp = o_tty->termios_locked;
1696 if (!devpts)
1697 o_tty->driver->termios_locked[idx] = NULL;
1698 kfree(tp);
1699 }
1700 o_tty->magic = 0;
1701 o_tty->driver->refcount--;
1702 file_list_lock();
1703 list_del_init(&o_tty->tty_files);
1704 file_list_unlock();
1705 free_tty_struct(o_tty);
1706 }
1707
1708 if (!devpts)
1709 tty->driver->ttys[idx] = NULL;
1710 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1711 tp = tty->termios;
1712 if (!devpts)
1713 tty->driver->termios[idx] = NULL;
1714 kfree(tp);
1715
1716 tp = tty->termios_locked;
1717 if (!devpts)
1718 tty->driver->termios_locked[idx] = NULL;
1719 kfree(tp);
1720 }
1721
1722 tty->magic = 0;
1723 tty->driver->refcount--;
1724 file_list_lock();
1725 list_del_init(&tty->tty_files);
1726 file_list_unlock();
1727 module_put(tty->driver->owner);
1728 free_tty_struct(tty);
1729}
1730
1731/*
1732 * Even releasing the tty structures is a tricky business.. We have
1733 * to be very careful that the structures are all released at the
1734 * same time, as interrupts might otherwise get the wrong pointers.
1735 *
1736 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1737 * lead to double frees or releasing memory still in use.
1738 */
1739static void release_dev(struct file * filp)
1740{
1741 struct tty_struct *tty, *o_tty;
1742 int pty_master, tty_closing, o_tty_closing, do_sleep;
1743 int devpts_master, devpts;
1744 int idx;
1745 char buf[64];
1746 unsigned long flags;
1747
1748 tty = (struct tty_struct *)filp->private_data;
1749 if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "release_dev"))
1750 return;
1751
1752 check_tty_count(tty, "release_dev");
1753
1754 tty_fasync(-1, filp, 0);
1755
1756 idx = tty->index;
1757 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1758 tty->driver->subtype == PTY_TYPE_MASTER);
1759 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1760 devpts_master = pty_master && devpts;
1761 o_tty = tty->link;
1762
1763#ifdef TTY_PARANOIA_CHECK
1764 if (idx < 0 || idx >= tty->driver->num) {
1765 printk(KERN_DEBUG "release_dev: bad idx when trying to "
1766 "free (%s)\n", tty->name);
1767 return;
1768 }
1769 if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1770 if (tty != tty->driver->ttys[idx]) {
1771 printk(KERN_DEBUG "release_dev: driver.table[%d] not tty "
1772 "for (%s)\n", idx, tty->name);
1773 return;
1774 }
1775 if (tty->termios != tty->driver->termios[idx]) {
1776 printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios "
1777 "for (%s)\n",
1778 idx, tty->name);
1779 return;
1780 }
1781 if (tty->termios_locked != tty->driver->termios_locked[idx]) {
1782 printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not "
1783 "termios_locked for (%s)\n",
1784 idx, tty->name);
1785 return;
1786 }
1787 }
1788#endif
1789
1790#ifdef TTY_DEBUG_HANGUP
1791 printk(KERN_DEBUG "release_dev of %s (tty count=%d)...",
1792 tty_name(tty, buf), tty->count);
1793#endif
1794
1795#ifdef TTY_PARANOIA_CHECK
1796 if (tty->driver->other &&
1797 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1798 if (o_tty != tty->driver->other->ttys[idx]) {
1799 printk(KERN_DEBUG "release_dev: other->table[%d] "
1800 "not o_tty for (%s)\n",
1801 idx, tty->name);
1802 return;
1803 }
1804 if (o_tty->termios != tty->driver->other->termios[idx]) {
1805 printk(KERN_DEBUG "release_dev: other->termios[%d] "
1806 "not o_termios for (%s)\n",
1807 idx, tty->name);
1808 return;
1809 }
1810 if (o_tty->termios_locked !=
1811 tty->driver->other->termios_locked[idx]) {
1812 printk(KERN_DEBUG "release_dev: other->termios_locked["
1813 "%d] not o_termios_locked for (%s)\n",
1814 idx, tty->name);
1815 return;
1816 }
1817 if (o_tty->link != tty) {
1818 printk(KERN_DEBUG "release_dev: bad pty pointers\n");
1819 return;
1820 }
1821 }
1822#endif
1823 if (tty->driver->close)
1824 tty->driver->close(tty, filp);
1825
1826 /*
1827 * Sanity check: if tty->count is going to zero, there shouldn't be
1828 * any waiters on tty->read_wait or tty->write_wait. We test the
1829 * wait queues and kick everyone out _before_ actually starting to
1830 * close. This ensures that we won't block while releasing the tty
1831 * structure.
1832 *
1833 * The test for the o_tty closing is necessary, since the master and
1834 * slave sides may close in any order. If the slave side closes out
1835 * first, its count will be one, since the master side holds an open.
1836 * Thus this test wouldn't be triggered at the time the slave closes,
1837 * so we do it now.
1838 *
1839 * Note that it's possible for the tty to be opened again while we're
1840 * flushing out waiters. By recalculating the closing flags before
1841 * each iteration we avoid any problems.
1842 */
1843 while (1) {
1844 /* Guard against races with tty->count changes elsewhere and
1845 opens on /dev/tty */
1846
70522e12 1847 mutex_lock(&tty_mutex);
1da177e4
LT		 1848 tty_closing = tty->count <= 1;
1849 o_tty_closing = o_tty &&
1850 (o_tty->count <= (pty_master ? 1 : 0));
1da177e4
LT		 1851 do_sleep = 0;
1852
1853 if (tty_closing) {
1854 if (waitqueue_active(&tty->read_wait)) {
1855 wake_up(&tty->read_wait);
1856 do_sleep++;
1857 }
1858 if (waitqueue_active(&tty->write_wait)) {
1859 wake_up(&tty->write_wait);
1860 do_sleep++;
1861 }
1862 }
1863 if (o_tty_closing) {
1864 if (waitqueue_active(&o_tty->read_wait)) {
1865 wake_up(&o_tty->read_wait);
1866 do_sleep++;
1867 }
1868 if (waitqueue_active(&o_tty->write_wait)) {
1869 wake_up(&o_tty->write_wait);
1870 do_sleep++;
1871 }
1872 }
1873 if (!do_sleep)
1874 break;
1875
1876 printk(KERN_WARNING "release_dev: %s: read/write wait queue "
1877 "active!\n", tty_name(tty, buf));
70522e12 1878 mutex_unlock(&tty_mutex);
1da177e4
LT		 1879 schedule();
1880 }
1881
1882 /*
1883 * The closing flags are now consistent with the open counts on
1884 * both sides, and we've completed the last operation that could
1885 * block, so it's safe to proceed with closing.
1886 */
1da177e4
LT		 1887 if (pty_master) {
1888 if (--o_tty->count < 0) {
1889 printk(KERN_WARNING "release_dev: bad pty slave count "
1890 "(%d) for %s\n",
1891 o_tty->count, tty_name(o_tty, buf));
1892 o_tty->count = 0;
1893 }
1894 }
1895 if (--tty->count < 0) {
1896 printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n",
1897 tty->count, tty_name(tty, buf));
1898 tty->count = 0;
1899 }
1da177e4
LT		 1900
1901 /*
1902 * We've decremented tty->count, so we need to remove this file
1903 * descriptor off the tty->tty_files list; this serves two
1904 * purposes:
1905 * - check_tty_count sees the correct number of file descriptors
1906 * associated with this tty.
1907 * - do_tty_hangup no longer sees this file descriptor as
1908 * something that needs to be handled for hangups.
1909 */
1910 file_kill(filp);
1911 filp->private_data = NULL;
1912
1913 /*
1914 * Perform some housekeeping before deciding whether to return.
1915 *
1916 * Set the TTY_CLOSING flag if this was the last open. In the
1917 * case of a pty we may have to wait around for the other side
1918 * to close, and TTY_CLOSING makes sure we can't be reopened.
1919 */
1920 if(tty_closing)
1921 set_bit(TTY_CLOSING, &tty->flags);
1922 if(o_tty_closing)
1923 set_bit(TTY_CLOSING, &o_tty->flags);
1924
1925 /*
1926 * If _either_ side is closing, make sure there aren't any
1927 * processes that still think tty or o_tty is their controlling
1928 * tty.
1929 */
1930 if (tty_closing || o_tty_closing) {
1931 struct task_struct *p;
1932
1933 read_lock(&tasklist_lock);
1934 do_each_task_pid(tty->session, PIDTYPE_SID, p) {
1935 p->signal->tty = NULL;
1936 } while_each_task_pid(tty->session, PIDTYPE_SID, p);
1937 if (o_tty)
1938 do_each_task_pid(o_tty->session, PIDTYPE_SID, p) {
1939 p->signal->tty = NULL;
1940 } while_each_task_pid(o_tty->session, PIDTYPE_SID, p);
1941 read_unlock(&tasklist_lock);
1942 }
1943
70522e12 1944 mutex_unlock(&tty_mutex);
da965822 1945
1da177e4
LT		 1946 /* check whether both sides are closing ... */
1947 if (!tty_closing || (o_tty && !o_tty_closing))
1948 return;
1949
1950#ifdef TTY_DEBUG_HANGUP
1951 printk(KERN_DEBUG "freeing tty structure...");
1952#endif
1953 /*
1954 * Prevent flush_to_ldisc() from rescheduling the work for later. Then
1955 * kill any delayed work. As this is the final close it does not
1956 * race with the set_ldisc code path.
1957 */
1958 clear_bit(TTY_LDISC, &tty->flags);
1959 clear_bit(TTY_DONT_FLIP, &tty->flags);
33f0f88f 1960 cancel_delayed_work(&tty->buf.work);
1da177e4
LT		 1961
1962 /*
33f0f88f 1963 * Wait for ->hangup_work and ->buf.work handlers to terminate
1da177e4
LT		 1964 */
1965
1966 flush_scheduled_work();
1967
1968 /*
1969 * Wait for any short term users (we know they are just driver
1970 * side waiters as the file is closing so user count on the file
1971 * side is zero.
1972 */
1973 spin_lock_irqsave(&tty_ldisc_lock, flags);
1974 while(tty->ldisc.refcount)
1975 {
1976 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
1977 wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0);
1978 spin_lock_irqsave(&tty_ldisc_lock, flags);
1979 }
1980 spin_unlock_irqrestore(&tty_ldisc_lock, flags);
1981 /*
1982 * Shutdown the current line discipline, and reset it to N_TTY.
1983 * N.B. why reset ldisc when we're releasing the memory??
1984 *
1985 * FIXME: this MUST get fixed for the new reflocking
1986 */
1987 if (tty->ldisc.close)
1988 (tty->ldisc.close)(tty);
1989 tty_ldisc_put(tty->ldisc.num);
1990
1991 /*
1992 * Switch the line discipline back
1993 */
1994 tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
1995 tty_set_termios_ldisc(tty,N_TTY);
1996 if (o_tty) {
1997 /* FIXME: could o_tty be in setldisc here ? */
1998 clear_bit(TTY_LDISC, &o_tty->flags);
1999 if (o_tty->ldisc.close)
2000 (o_tty->ldisc.close)(o_tty);
2001 tty_ldisc_put(o_tty->ldisc.num);
2002 tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY));
2003 tty_set_termios_ldisc(o_tty,N_TTY);
2004 }
2005 /*
2006 * The release_mem function takes care of the details of clearing
2007 * the slots and preserving the termios structure.
2008 */
2009 release_mem(tty, idx);
2010
2011#ifdef CONFIG_UNIX98_PTYS
2012 /* Make this pty number available for reallocation */
2013 if (devpts) {
2014 down(&allocated_ptys_lock);
2015 idr_remove(&allocated_ptys, idx);
2016 up(&allocated_ptys_lock);
2017 }
2018#endif
2019
2020}
2021
2022/*
2023 * tty_open and tty_release keep up the tty count that contains the
2024 * number of opens done on a tty. We cannot use the inode-count, as
2025 * different inodes might point to the same tty.
2026 *
2027 * Open-counting is needed for pty masters, as well as for keeping
2028 * track of serial lines: DTR is dropped when the last close happens.
2029 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2030 *
2031 * The termios state of a pty is reset on first open so that
2032 * settings don't persist across reuse.
2033 */
2034static int tty_open(struct inode * inode, struct file * filp)
2035{
2036 struct tty_struct *tty;
2037 int noctty, retval;
2038 struct tty_driver *driver;
2039 int index;
2040 dev_t device = inode->i_rdev;
2041 unsigned short saved_flags = filp->f_flags;
2042
2043 nonseekable_open(inode, filp);
2044
2045retry_open:
2046 noctty = filp->f_flags & O_NOCTTY;
2047 index = -1;
2048 retval = 0;
2049
70522e12 2050 mutex_lock(&tty_mutex);
1da177e4
LT		 2051
2052 if (device == MKDEV(TTYAUX_MAJOR,0)) {
2053 if (!current->signal->tty) {
70522e12 2054 mutex_unlock(&tty_mutex);
1da177e4
LT		 2055 return -ENXIO;
2056 }
2057 driver = current->signal->tty->driver;
2058 index = current->signal->tty->index;
2059 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
2060 /* noctty = 1; */
2061 goto got_driver;
2062 }
2063#ifdef CONFIG_VT
2064 if (device == MKDEV(TTY_MAJOR,0)) {
2065 extern struct tty_driver *console_driver;
2066 driver = console_driver;
2067 index = fg_console;
2068 noctty = 1;
2069 goto got_driver;
2070 }
2071#endif
2072 if (device == MKDEV(TTYAUX_MAJOR,1)) {
2073 driver = console_device(&index);
2074 if (driver) {
2075 /* Don't let /dev/console block */
2076 filp->f_flags |= O_NONBLOCK;
2077 noctty = 1;
2078 goto got_driver;
2079 }
70522e12 2080 mutex_unlock(&tty_mutex);
1da177e4
LT		 2081 return -ENODEV;
2082 }
2083
2084 driver = get_tty_driver(device, &index);
2085 if (!driver) {
70522e12 2086 mutex_unlock(&tty_mutex);
1da177e4
LT		 2087 return -ENODEV;
2088 }
2089got_driver:
2090 retval = init_dev(driver, index, &tty);
70522e12 2091 mutex_unlock(&tty_mutex);
1da177e4
LT		 2092 if (retval)
2093 return retval;
2094
2095 filp->private_data = tty;
2096 file_move(filp, &tty->tty_files);
2097 check_tty_count(tty, "tty_open");
2098 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2099 tty->driver->subtype == PTY_TYPE_MASTER)
2100 noctty = 1;
2101#ifdef TTY_DEBUG_HANGUP
2102 printk(KERN_DEBUG "opening %s...", tty->name);
2103#endif
2104 if (!retval) {
2105 if (tty->driver->open)
2106 retval = tty->driver->open(tty, filp);
2107 else
2108 retval = -ENODEV;
2109 }
2110 filp->f_flags = saved_flags;
2111
2112 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
2113 retval = -EBUSY;
2114
2115 if (retval) {
2116#ifdef TTY_DEBUG_HANGUP
2117 printk(KERN_DEBUG "error %d in opening %s...", retval,
2118 tty->name);
2119#endif
2120 release_dev(filp);
2121 if (retval != -ERESTARTSYS)
2122 return retval;
2123 if (signal_pending(current))
2124 return retval;
2125 schedule();
2126 /*
2127 * Need to reset f_op in case a hangup happened.
2128 */
2129 if (filp->f_op == &hung_up_tty_fops)
2130 filp->f_op = &tty_fops;
2131 goto retry_open;
2132 }
2133 if (!noctty &&
2134 current->signal->leader &&
2135 !current->signal->tty &&
2136 tty->session == 0) {
2137 task_lock(current);
2138 current->signal->tty = tty;
2139 task_unlock(current);
2140 current->signal->tty_old_pgrp = 0;
2141 tty->session = current->signal->session;
2142 tty->pgrp = process_group(current);
2143 }
2144 return 0;
2145}
2146
2147#ifdef CONFIG_UNIX98_PTYS
2148static int ptmx_open(struct inode * inode, struct file * filp)
2149{
2150 struct tty_struct *tty;
2151 int retval;
2152 int index;
2153 int idr_ret;
2154
2155 nonseekable_open(inode, filp);
2156
2157 /* find a device that is not in use. */
2158 down(&allocated_ptys_lock);
2159 if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) {
2160 up(&allocated_ptys_lock);
2161 return -ENOMEM;
2162 }
2163 idr_ret = idr_get_new(&allocated_ptys, NULL, &index);
2164 if (idr_ret < 0) {
2165 up(&allocated_ptys_lock);
2166 if (idr_ret == -EAGAIN)
2167 return -ENOMEM;
2168 return -EIO;
2169 }
2170 if (index >= pty_limit) {
2171 idr_remove(&allocated_ptys, index);
2172 up(&allocated_ptys_lock);
2173 return -EIO;
2174 }
2175 up(&allocated_ptys_lock);
2176
70522e12 2177 mutex_lock(&tty_mutex);
1da177e4 2178 retval = init_dev(ptm_driver, index, &tty);
70522e12 2179 mutex_unlock(&tty_mutex);
1da177e4
LT		 2180
2181 if (retval)
2182 goto out;
2183
2184 set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
2185 filp->private_data = tty;
2186 file_move(filp, &tty->tty_files);
2187
2188 retval = -ENOMEM;
2189 if (devpts_pty_new(tty->link))
2190 goto out1;
2191
2192 check_tty_count(tty, "tty_open");
2193 retval = ptm_driver->open(tty, filp);
2194 if (!retval)
2195 return 0;
2196out1:
2197 release_dev(filp);
2198out:
2199 down(&allocated_ptys_lock);
2200 idr_remove(&allocated_ptys, index);
2201 up(&allocated_ptys_lock);
2202 return retval;
2203}
2204#endif
2205
2206static int tty_release(struct inode * inode, struct file * filp)
2207{
2208 lock_kernel();
2209 release_dev(filp);
2210 unlock_kernel();
2211 return 0;
2212}
2213
2214/* No kernel lock held - fine */
2215static unsigned int tty_poll(struct file * filp, poll_table * wait)
2216{
2217 struct tty_struct * tty;
2218 struct tty_ldisc *ld;
2219 int ret = 0;
2220
2221 tty = (struct tty_struct *)filp->private_data;
2222 if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_poll"))
2223 return 0;
2224
2225 ld = tty_ldisc_ref_wait(tty);
2226 if (ld->poll)
2227 ret = (ld->poll)(tty, filp, wait);
2228 tty_ldisc_deref(ld);
2229 return ret;
2230}
2231
2232static int tty_fasync(int fd, struct file * filp, int on)
2233{
2234 struct tty_struct * tty;
2235 int retval;
2236
2237 tty = (struct tty_struct *)filp->private_data;
2238 if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_fasync"))
2239 return 0;
2240
2241 retval = fasync_helper(fd, filp, on, &tty->fasync);
2242 if (retval <= 0)
2243 return retval;
2244
2245 if (on) {
2246 if (!waitqueue_active(&tty->read_wait))
2247 tty->minimum_to_wake = 1;
2248 retval = f_setown(filp, (-tty->pgrp) ? : current->pid, 0);
2249 if (retval)
2250 return retval;
2251 } else {
2252 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2253 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2254 }
2255 return 0;
2256}
2257
2258static int tiocsti(struct tty_struct *tty, char __user *p)
2259{
2260 char ch, mbz = 0;
2261 struct tty_ldisc *ld;
2262
2263 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2264 return -EPERM;
2265 if (get_user(ch, p))
2266 return -EFAULT;
2267 ld = tty_ldisc_ref_wait(tty);
2268 ld->receive_buf(tty, &ch, &mbz, 1);
2269 tty_ldisc_deref(ld);
2270 return 0;
2271}
2272
2273static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg)
2274{
2275 if (copy_to_user(arg, &tty->winsize, sizeof(*arg)))
2276 return -EFAULT;
2277 return 0;
2278}
2279
2280static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
2281 struct winsize __user * arg)
2282{
2283 struct winsize tmp_ws;
2284
2285 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2286 return -EFAULT;
2287 if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg)))
2288 return 0;
2289#ifdef CONFIG_VT
2290 if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) {
2291 int rc;
2292
2293 acquire_console_sem();
2294 rc = vc_resize(tty->driver_data, tmp_ws.ws_col, tmp_ws.ws_row);
2295 release_console_sem();
2296 if (rc)
2297 return -ENXIO;
2298 }
2299#endif
2300 if (tty->pgrp > 0)
2301 kill_pg(tty->pgrp, SIGWINCH, 1);
2302 if ((real_tty->pgrp != tty->pgrp) && (real_tty->pgrp > 0))
2303 kill_pg(real_tty->pgrp, SIGWINCH, 1);
2304 tty->winsize = tmp_ws;
2305 real_tty->winsize = tmp_ws;
2306 return 0;
2307}
2308
2309static int tioccons(struct file *file)
2310{
2311 if (!capable(CAP_SYS_ADMIN))
2312 return -EPERM;
2313 if (file->f_op->write == redirected_tty_write) {
2314 struct file *f;
2315 spin_lock(&redirect_lock);
2316 f = redirect;
2317 redirect = NULL;
2318 spin_unlock(&redirect_lock);
2319 if (f)
2320 fput(f);
2321 return 0;
2322 }
2323 spin_lock(&redirect_lock);
2324 if (redirect) {
2325 spin_unlock(&redirect_lock);
2326 return -EBUSY;
2327 }
2328 get_file(file);
2329 redirect = file;
2330 spin_unlock(&redirect_lock);
2331 return 0;
2332}
2333
2334
2335static int fionbio(struct file *file, int __user *p)
2336{
2337 int nonblock;
2338
2339 if (get_user(nonblock, p))
2340 return -EFAULT;
2341
2342 if (nonblock)
2343 file->f_flags |= O_NONBLOCK;
2344 else
2345 file->f_flags &= ~O_NONBLOCK;
2346 return 0;
2347}
2348
2349static int tiocsctty(struct tty_struct *tty, int arg)
2350{
2351 task_t *p;
2352
2353 if (current->signal->leader &&
2354 (current->signal->session == tty->session))
2355 return 0;
2356 /*
2357 * The process must be a session leader and
2358 * not have a controlling tty already.
2359 */
2360 if (!current->signal->leader || current->signal->tty)
2361 return -EPERM;
2362 if (tty->session > 0) {
2363 /*
2364 * This tty is already the controlling
2365 * tty for another session group!
2366 */
2367 if ((arg == 1) && capable(CAP_SYS_ADMIN)) {
2368 /*
2369 * Steal it away
2370 */
2371
2372 read_lock(&tasklist_lock);
2373 do_each_task_pid(tty->session, PIDTYPE_SID, p) {
2374 p->signal->tty = NULL;
2375 } while_each_task_pid(tty->session, PIDTYPE_SID, p);
2376 read_unlock(&tasklist_lock);
2377 } else
2378 return -EPERM;
2379 }
2380 task_lock(current);
2381 current->signal->tty = tty;
2382 task_unlock(current);
2383 current->signal->tty_old_pgrp = 0;
2384 tty->session = current->signal->session;
2385 tty->pgrp = process_group(current);
2386 return 0;
2387}
2388
2389static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2390{
2391 /*
2392 * (tty == real_tty) is a cheap way of
2393 * testing if the tty is NOT a master pty.
2394 */
2395 if (tty == real_tty && current->signal->tty != real_tty)
2396 return -ENOTTY;
2397 return put_user(real_tty->pgrp, p);
2398}
2399
2400static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2401{
2402 pid_t pgrp;
2403 int retval = tty_check_change(real_tty);
2404
2405 if (retval == -EIO)
2406 return -ENOTTY;
2407 if (retval)
2408 return retval;
2409 if (!current->signal->tty ||
2410 (current->signal->tty != real_tty) ||
2411 (real_tty->session != current->signal->session))
2412 return -ENOTTY;
2413 if (get_user(pgrp, p))
2414 return -EFAULT;
2415 if (pgrp < 0)
2416 return -EINVAL;
2417 if (session_of_pgrp(pgrp) != current->signal->session)
2418 return -EPERM;
2419 real_tty->pgrp = pgrp;
2420 return 0;
2421}
2422
2423static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2424{
2425 /*
2426 * (tty == real_tty) is a cheap way of
2427 * testing if the tty is NOT a master pty.
2428 */
2429 if (tty == real_tty && current->signal->tty != real_tty)
2430 return -ENOTTY;
2431 if (real_tty->session <= 0)
2432 return -ENOTTY;
2433 return put_user(real_tty->session, p);
2434}
2435
2436static int tiocsetd(struct tty_struct *tty, int __user *p)
2437{
2438 int ldisc;
2439
2440 if (get_user(ldisc, p))
2441 return -EFAULT;
2442 return tty_set_ldisc(tty, ldisc);
2443}
2444
b20f3ae5 2445static int send_break(struct tty_struct *tty, unsigned int duration)
1da177e4
LT		 2446{
2447 tty->driver->break_ctl(tty, -1);
2448 if (!signal_pending(current)) {
b20f3ae5 2449 msleep_interruptible(duration);
1da177e4
LT		 2450 }
2451 tty->driver->break_ctl(tty, 0);
2452 if (signal_pending(current))
2453 return -EINTR;
2454 return 0;
2455}
2456
2457static int
2458tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2459{
2460 int retval = -EINVAL;
2461
2462 if (tty->driver->tiocmget) {
2463 retval = tty->driver->tiocmget(tty, file);
2464
2465 if (retval >= 0)
2466 retval = put_user(retval, p);
2467 }
2468 return retval;
2469}
2470
2471static int
2472tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2473 unsigned __user *p)
2474{
2475 int retval = -EINVAL;
2476
2477 if (tty->driver->tiocmset) {
2478 unsigned int set, clear, val;
2479
2480 retval = get_user(val, p);
2481 if (retval)
2482 return retval;
2483
2484 set = clear = 0;
2485 switch (cmd) {
2486 case TIOCMBIS:
2487 set = val;
2488 break;
2489 case TIOCMBIC:
2490 clear = val;
2491 break;
2492 case TIOCMSET:
2493 set = val;
2494 clear = ~val;
2495 break;
2496 }
2497
2498 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2499 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2500
2501 retval = tty->driver->tiocmset(tty, file, set, clear);
2502 }
2503 return retval;
2504}
2505
2506/*
2507 * Split this up, as gcc can choke on it otherwise..
2508 */
2509int tty_ioctl(struct inode * inode, struct file * file,
2510 unsigned int cmd, unsigned long arg)
2511{
2512 struct tty_struct *tty, *real_tty;
2513 void __user *p = (void __user *)arg;
2514 int retval;
2515 struct tty_ldisc *ld;
2516
2517 tty = (struct tty_struct *)file->private_data;
2518 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2519 return -EINVAL;
2520
2521 real_tty = tty;
2522 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2523 tty->driver->subtype == PTY_TYPE_MASTER)
2524 real_tty = tty->link;
2525
2526 /*
2527 * Break handling by driver
2528 */
2529 if (!tty->driver->break_ctl) {
2530 switch(cmd) {
2531 case TIOCSBRK:
2532 case TIOCCBRK:
2533 if (tty->driver->ioctl)
2534 return tty->driver->ioctl(tty, file, cmd, arg);
2535 return -EINVAL;
2536
2537 /* These two ioctl's always return success; even if */
2538 /* the driver doesn't support them. */
2539 case TCSBRK:
2540 case TCSBRKP:
2541 if (!tty->driver->ioctl)
2542 return 0;
2543 retval = tty->driver->ioctl(tty, file, cmd, arg);
2544 if (retval == -ENOIOCTLCMD)
2545 retval = 0;
2546 return retval;
2547 }
2548 }
2549
2550 /*
2551 * Factor out some common prep work
2552 */
2553 switch (cmd) {
2554 case TIOCSETD:
2555 case TIOCSBRK:
2556 case TIOCCBRK:
2557 case TCSBRK:
2558 case TCSBRKP:
2559 retval = tty_check_change(tty);
2560 if (retval)
2561 return retval;
2562 if (cmd != TIOCCBRK) {
2563 tty_wait_until_sent(tty, 0);
2564 if (signal_pending(current))
2565 return -EINTR;
2566 }
2567 break;
2568 }
2569
2570 switch (cmd) {
2571 case TIOCSTI:
2572 return tiocsti(tty, p);
2573 case TIOCGWINSZ:
2574 return tiocgwinsz(tty, p);
2575 case TIOCSWINSZ:
2576 return tiocswinsz(tty, real_tty, p);
2577 case TIOCCONS:
2578 return real_tty!=tty ? -EINVAL : tioccons(file);
2579 case FIONBIO:
2580 return fionbio(file, p);
2581 case TIOCEXCL:
2582 set_bit(TTY_EXCLUSIVE, &tty->flags);
2583 return 0;
2584 case TIOCNXCL:
2585 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2586 return 0;
2587 case TIOCNOTTY:
2588 if (current->signal->tty != tty)
2589 return -ENOTTY;
2590 if (current->signal->leader)
2591 disassociate_ctty(0);
2592 task_lock(current);
2593 current->signal->tty = NULL;
2594 task_unlock(current);
2595 return 0;
2596 case TIOCSCTTY:
2597 return tiocsctty(tty, arg);
2598 case TIOCGPGRP:
2599 return tiocgpgrp(tty, real_tty, p);
2600 case TIOCSPGRP:
2601 return tiocspgrp(tty, real_tty, p);
2602 case TIOCGSID:
2603 return tiocgsid(tty, real_tty, p);
2604 case TIOCGETD:
2605 /* FIXME: check this is ok */
2606 return put_user(tty->ldisc.num, (int __user *)p);
2607 case TIOCSETD:
2608 return tiocsetd(tty, p);
2609#ifdef CONFIG_VT
2610 case TIOCLINUX:
2611 return tioclinux(tty, arg);
2612#endif
2613 /*
2614 * Break handling
2615 */
2616 case TIOCSBRK: /* Turn break on, unconditionally */
2617 tty->driver->break_ctl(tty, -1);
2618 return 0;
2619
2620 case TIOCCBRK: /* Turn break off, unconditionally */
2621 tty->driver->break_ctl(tty, 0);
2622 return 0;
2623 case TCSBRK: /* SVID version: non-zero arg --> no break */
2624 /*
2625 * XXX is the above comment correct, or the
2626 * code below correct? Is this ioctl used at
2627 * all by anyone?
2628 */
2629 if (!arg)
b20f3ae5 2630 return send_break(tty, 250);
1da177e4
LT		 2631 return 0;
2632 case TCSBRKP: /* support for POSIX tcsendbreak() */
b20f3ae5 2633 return send_break(tty, arg ? arg*100 : 250);
1da177e4
LT		 2634
2635 case TIOCMGET:
2636 return tty_tiocmget(tty, file, p);
2637
2638 case TIOCMSET:
2639 case TIOCMBIC:
2640 case TIOCMBIS:
2641 return tty_tiocmset(tty, file, cmd, p);
2642 }
2643 if (tty->driver->ioctl) {
2644 retval = (tty->driver->ioctl)(tty, file, cmd, arg);
2645 if (retval != -ENOIOCTLCMD)
2646 return retval;
2647 }
2648 ld = tty_ldisc_ref_wait(tty);
2649 retval = -EINVAL;
2650 if (ld->ioctl) {
2651 retval = ld->ioctl(tty, file, cmd, arg);
2652 if (retval == -ENOIOCTLCMD)
2653 retval = -EINVAL;
2654 }
2655 tty_ldisc_deref(ld);
2656 return retval;
2657}
2658
2659
2660/*
2661 * This implements the "Secure Attention Key" --- the idea is to
2662 * prevent trojan horses by killing all processes associated with this
2663 * tty when the user hits the "Secure Attention Key". Required for
2664 * super-paranoid applications --- see the Orange Book for more details.
2665 *
2666 * This code could be nicer; ideally it should send a HUP, wait a few
2667 * seconds, then send a INT, and then a KILL signal. But you then
2668 * have to coordinate with the init process, since all processes associated
2669 * with the current tty must be dead before the new getty is allowed
2670 * to spawn.
2671 *
2672 * Now, if it would be correct ;-/ The current code has a nasty hole -
2673 * it doesn't catch files in flight. We may send the descriptor to ourselves
2674 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2675 *
2676 * Nasty bug: do_SAK is being called in interrupt context. This can
2677 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2678 */
2679static void __do_SAK(void *arg)
2680{
2681#ifdef TTY_SOFT_SAK
2682 tty_hangup(tty);
2683#else
2684 struct tty_struct *tty = arg;
652486fb 2685 struct task_struct *g, *p;
1da177e4
LT		 2686 int session;
2687 int i;
2688 struct file *filp;
2689 struct tty_ldisc *disc;
badf1662 2690 struct fdtable *fdt;
1da177e4
LT		 2691
2692 if (!tty)
2693 return;
2694 session = tty->session;
2695
2696 /* We don't want an ldisc switch during this */
2697 disc = tty_ldisc_ref(tty);
2698 if (disc && disc->flush_buffer)
2699 disc->flush_buffer(tty);
2700 tty_ldisc_deref(disc);
2701
2702 if (tty->driver->flush_buffer)
2703 tty->driver->flush_buffer(tty);
2704
2705 read_lock(&tasklist_lock);
652486fb 2706 /* Kill the entire session */
1da177e4 2707 do_each_task_pid(session, PIDTYPE_SID, p) {
652486fb
EB		 2708 printk(KERN_NOTICE "SAK: killed process %d"
2709 " (%s): p->signal->session==tty->session\n",
2710 p->pid, p->comm);
2711 send_sig(SIGKILL, p, 1);
2712 } while_each_task_pid(session, PIDTYPE_SID, p);
2713 /* Now kill any processes that happen to have the
2714 * tty open.
2715 */
2716 do_each_thread(g, p) {
2717 if (p->signal->tty == tty) {
1da177e4
LT		 2718 printk(KERN_NOTICE "SAK: killed process %d"
2719 " (%s): p->signal->session==tty->session\n",
2720 p->pid, p->comm);
2721 send_sig(SIGKILL, p, 1);
2722 continue;
2723 }
2724 task_lock(p);
2725 if (p->files) {
b835996f 2726 rcu_read_lock();
badf1662
DS		 2727 fdt = files_fdtable(p->files);
2728 for (i=0; i < fdt->max_fds; i++) {
1da177e4
LT		 2729 filp = fcheck_files(p->files, i);
2730 if (!filp)
2731 continue;
2732 if (filp->f_op->read == tty_read &&
2733 filp->private_data == tty) {
2734 printk(KERN_NOTICE "SAK: killed process %d"
2735 " (%s): fd#%d opened to the tty\n",
2736 p->pid, p->comm, i);
2737 send_sig(SIGKILL, p, 1);
2738 break;
2739 }
2740 }
b835996f 2741 rcu_read_unlock();
1da177e4
LT		 2742 }
2743 task_unlock(p);
652486fb 2744 } while_each_thread(g, p);
1da177e4
LT		 2745 read_unlock(&tasklist_lock);
2746#endif
2747}
2748
2749/*
2750 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2751 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2752 * the values which we write to it will be identical to the values which it
2753 * already has. --akpm
2754 */
2755void do_SAK(struct tty_struct *tty)
2756{
2757 if (!tty)
2758 return;
2759 PREPARE_WORK(&tty->SAK_work, __do_SAK, tty);
2760 schedule_work(&tty->SAK_work);
2761}
2762
2763EXPORT_SYMBOL(do_SAK);
2764
2765/*
2766 * This routine is called out of the software interrupt to flush data
33f0f88f 2767 * from the buffer chain to the line discipline.
1da177e4
LT		 2768 */
2769
2770static void flush_to_ldisc(void *private_)
2771{
2772 struct tty_struct *tty = (struct tty_struct *) private_;
1da177e4
LT		 2773 unsigned long flags;
2774 struct tty_ldisc *disc;
33f0f88f 2775 struct tty_buffer *tbuf;
8977d929
PF		 2776 int count;
2777 char *char_buf;
2778 unsigned char *flag_buf;
1da177e4
LT		 2779
2780 disc = tty_ldisc_ref(tty);
2781 if (disc == NULL) /* !TTY_LDISC */
2782 return;
2783
2784 if (test_bit(TTY_DONT_FLIP, &tty->flags)) {
2785 /*
2786 * Do it after the next timer tick:
2787 */
33f0f88f 2788 schedule_delayed_work(&tty->buf.work, 1);
1da177e4
LT		 2789 goto out;
2790 }
808249ce 2791 spin_lock_irqsave(&tty->buf.lock, flags);
8977d929
PF		 2792 while((tbuf = tty->buf.head) != NULL) {
2793 while ((count = tbuf->commit - tbuf->read) != 0) {
2794 char_buf = tbuf->char_buf_ptr + tbuf->read;
2795 flag_buf = tbuf->flag_buf_ptr + tbuf->read;
2796 tbuf->read += count;
2797 spin_unlock_irqrestore(&tty->buf.lock, flags);
2798 disc->receive_buf(tty, char_buf, flag_buf, count);
2799 spin_lock_irqsave(&tty->buf.lock, flags);
2800 }
2801 if (tbuf->active)
2802 break;
33f0f88f 2803 tty->buf.head = tbuf->next;
607f4e38
PF		 2804 if (tty->buf.head == NULL)
2805 tty->buf.tail = NULL;
33f0f88f
AC		 2806 tty_buffer_free(tty, tbuf);
2807 }
808249ce 2808 spin_unlock_irqrestore(&tty->buf.lock, flags);
1da177e4
LT		 2809out:
2810 tty_ldisc_deref(disc);
2811}
2812
2813/*
2814 * Routine which returns the baud rate of the tty
2815 *
2816 * Note that the baud_table needs to be kept in sync with the
2817 * include/asm/termbits.h file.
2818 */
2819static int baud_table[] = {
2820 0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
2821 9600, 19200, 38400, 57600, 115200, 230400, 460800,
2822#ifdef __sparc__
2823 76800, 153600, 307200, 614400, 921600
2824#else
2825 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
2826 2500000, 3000000, 3500000, 4000000
2827#endif
2828};
2829
2830static int n_baud_table = ARRAY_SIZE(baud_table);
2831
2832/**
2833 * tty_termios_baud_rate
2834 * @termios: termios structure
2835 *
2836 * Convert termios baud rate data into a speed. This should be called
2837 * with the termios lock held if this termios is a terminal termios
2838 * structure. May change the termios data.
2839 */
2840
2841int tty_termios_baud_rate(struct termios *termios)
2842{
2843 unsigned int cbaud;
2844
2845 cbaud = termios->c_cflag & CBAUD;
2846
2847 if (cbaud & CBAUDEX) {
2848 cbaud &= ~CBAUDEX;
2849
2850 if (cbaud < 1 || cbaud + 15 > n_baud_table)
2851 termios->c_cflag &= ~CBAUDEX;
2852 else
2853 cbaud += 15;
2854 }
2855 return baud_table[cbaud];
2856}
2857
2858EXPORT_SYMBOL(tty_termios_baud_rate);
2859
2860/**
2861 * tty_get_baud_rate - get tty bit rates
2862 * @tty: tty to query
2863 *
2864 * Returns the baud rate as an integer for this terminal. The
2865 * termios lock must be held by the caller and the terminal bit
2866 * flags may be updated.
2867 */
2868
2869int tty_get_baud_rate(struct tty_struct *tty)
2870{
2871 int baud = tty_termios_baud_rate(tty->termios);
2872
2873 if (baud == 38400 && tty->alt_speed) {
2874 if (!tty->warned) {
2875 printk(KERN_WARNING "Use of setserial/setrocket to "
2876 "set SPD_* flags is deprecated\n");
2877 tty->warned = 1;
2878 }
2879 baud = tty->alt_speed;
2880 }
2881
2882 return baud;
2883}
2884
2885EXPORT_SYMBOL(tty_get_baud_rate);
2886
2887/**
2888 * tty_flip_buffer_push - terminal
2889 * @tty: tty to push
2890 *
2891 * Queue a push of the terminal flip buffers to the line discipline. This
2892 * function must not be called from IRQ context if tty->low_latency is set.
2893 *
2894 * In the event of the queue being busy for flipping the work will be
2895 * held off and retried later.
2896 */
2897
2898void tty_flip_buffer_push(struct tty_struct *tty)
2899{
808249ce
PF		 2900 unsigned long flags;
2901 spin_lock_irqsave(&tty->buf.lock, flags);
8977d929 2902 if (tty->buf.tail != NULL) {
808249ce 2903 tty->buf.tail->active = 0;
8977d929
PF		 2904 tty->buf.tail->commit = tty->buf.tail->used;
2905 }
808249ce
PF		 2906 spin_unlock_irqrestore(&tty->buf.lock, flags);
2907
1da177e4
LT		 2908 if (tty->low_latency)
2909 flush_to_ldisc((void *) tty);
2910 else
33f0f88f 2911 schedule_delayed_work(&tty->buf.work, 1);
1da177e4
LT		 2912}
2913
2914EXPORT_SYMBOL(tty_flip_buffer_push);
2915
33f0f88f 2916
1da177e4
LT		 2917/*
2918 * This subroutine initializes a tty structure.
2919 */
2920static void initialize_tty_struct(struct tty_struct *tty)
2921{
2922 memset(tty, 0, sizeof(struct tty_struct));
2923 tty->magic = TTY_MAGIC;
2924 tty_ldisc_assign(tty, tty_ldisc_get(N_TTY));
2925 tty->pgrp = -1;
2926 tty->overrun_time = jiffies;
33f0f88f
AC		 2927 tty->buf.head = tty->buf.tail = NULL;
2928 tty_buffer_init(tty);
2929 INIT_WORK(&tty->buf.work, flush_to_ldisc, tty);
2930 init_MUTEX(&tty->buf.pty_sem);
1da177e4
LT		 2931 init_MUTEX(&tty->termios_sem);
2932 init_waitqueue_head(&tty->write_wait);
2933 init_waitqueue_head(&tty->read_wait);
2934 INIT_WORK(&tty->hangup_work, do_tty_hangup, tty);
70522e12
IM		 2935 mutex_init(&tty->atomic_read_lock);
2936 mutex_init(&tty->atomic_write_lock);
1da177e4
LT		 2937 spin_lock_init(&tty->read_lock);
2938 INIT_LIST_HEAD(&tty->tty_files);
2939 INIT_WORK(&tty->SAK_work, NULL, NULL);
2940}
2941
2942/*
2943 * The default put_char routine if the driver did not define one.
2944 */
2945static void tty_default_put_char(struct tty_struct *tty, unsigned char ch)
2946{
2947 tty->driver->write(tty, &ch, 1);
2948}
2949
7fe845d1 2950static struct class *tty_class;
1da177e4
LT		 2951
2952/**
2953 * tty_register_device - register a tty device
2954 * @driver: the tty driver that describes the tty device
2955 * @index: the index in the tty driver for this tty device
2956 * @device: a struct device that is associated with this tty device.
2957 * This field is optional, if there is no known struct device for this
2958 * tty device it can be set to NULL safely.
2959 *
2960 * This call is required to be made to register an individual tty device if
2961 * the tty driver's flags have the TTY_DRIVER_NO_DEVFS bit set. If that
2962 * bit is not set, this function should not be called.
2963 */
2964void tty_register_device(struct tty_driver *driver, unsigned index,
2965 struct device *device)
2966{
2967 char name[64];
2968 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2969
2970 if (index >= driver->num) {
2971 printk(KERN_ERR "Attempt to register invalid tty line number "
2972 " (%d).\n", index);
2973 return;
2974 }
2975
2976 devfs_mk_cdev(dev, S_IFCHR | S_IRUSR | S_IWUSR,
2977 "%s%d", driver->devfs_name, index + driver->name_base);
2978
2979 if (driver->type == TTY_DRIVER_TYPE_PTY)
2980 pty_line_name(driver, index, name);
2981 else
2982 tty_line_name(driver, index, name);
53f46542 2983 class_device_create(tty_class, NULL, dev, device, "%s", name);
1da177e4
LT		 2984}
2985
2986/**
2987 * tty_unregister_device - unregister a tty device
2988 * @driver: the tty driver that describes the tty device
2989 * @index: the index in the tty driver for this tty device
2990 *
2991 * If a tty device is registered with a call to tty_register_device() then
2992 * this function must be made when the tty device is gone.
2993 */
2994void tty_unregister_device(struct tty_driver *driver, unsigned index)
2995{
2996 devfs_remove("%s%d", driver->devfs_name, index + driver->name_base);
7fe845d1 2997 class_device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index);
1da177e4
LT		 2998}
2999
3000EXPORT_SYMBOL(tty_register_device);
3001EXPORT_SYMBOL(tty_unregister_device);
3002
3003struct tty_driver *alloc_tty_driver(int lines)
3004{
3005 struct tty_driver *driver;
3006
3007 driver = kmalloc(sizeof(struct tty_driver), GFP_KERNEL);
3008 if (driver) {
3009 memset(driver, 0, sizeof(struct tty_driver));
3010 driver->magic = TTY_DRIVER_MAGIC;
3011 driver->num = lines;
3012 /* later we'll move allocation of tables here */
3013 }
3014 return driver;
3015}
3016
3017void put_tty_driver(struct tty_driver *driver)
3018{
3019 kfree(driver);
3020}
3021
3022void tty_set_operations(struct tty_driver *driver, struct tty_operations *op)
3023{
3024 driver->open = op->open;
3025 driver->close = op->close;
3026 driver->write = op->write;
3027 driver->put_char = op->put_char;
3028 driver->flush_chars = op->flush_chars;
3029 driver->write_room = op->write_room;
3030 driver->chars_in_buffer = op->chars_in_buffer;
3031 driver->ioctl = op->ioctl;
3032 driver->set_termios = op->set_termios;
3033 driver->throttle = op->throttle;
3034 driver->unthrottle = op->unthrottle;
3035 driver->stop = op->stop;
3036 driver->start = op->start;
3037 driver->hangup = op->hangup;
3038 driver->break_ctl = op->break_ctl;
3039 driver->flush_buffer = op->flush_buffer;
3040 driver->set_ldisc = op->set_ldisc;
3041 driver->wait_until_sent = op->wait_until_sent;
3042 driver->send_xchar = op->send_xchar;
3043 driver->read_proc = op->read_proc;
3044 driver->write_proc = op->write_proc;
3045 driver->tiocmget = op->tiocmget;
3046 driver->tiocmset = op->tiocmset;
3047}
3048
3049
3050EXPORT_SYMBOL(alloc_tty_driver);
3051EXPORT_SYMBOL(put_tty_driver);
3052EXPORT_SYMBOL(tty_set_operations);
3053
3054/*
3055 * Called by a tty driver to register itself.
3056 */
3057int tty_register_driver(struct tty_driver *driver)
3058{
3059 int error;
3060 int i;
3061 dev_t dev;
3062 void **p = NULL;
3063
3064 if (driver->flags & TTY_DRIVER_INSTALLED)
3065 return 0;
3066
3067 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
3068 p = kmalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL);
3069 if (!p)
3070 return -ENOMEM;
3071 memset(p, 0, driver->num * 3 * sizeof(void *));
3072 }
3073
3074 if (!driver->major) {
3075 error = alloc_chrdev_region(&dev, driver->minor_start, driver->num,
3076 (char*)driver->name);
3077 if (!error) {
3078 driver->major = MAJOR(dev);
3079 driver->minor_start = MINOR(dev);
3080 }
3081 } else {
3082 dev = MKDEV(driver->major, driver->minor_start);
3083 error = register_chrdev_region(dev, driver->num,
3084 (char*)driver->name);
3085 }
3086 if (error < 0) {
3087 kfree(p);
3088 return error;
3089 }
3090
3091 if (p) {
3092 driver->ttys = (struct tty_struct **)p;
3093 driver->termios = (struct termios **)(p + driver->num);
3094 driver->termios_locked = (struct termios **)(p + driver->num * 2);
3095 } else {
3096 driver->ttys = NULL;
3097 driver->termios = NULL;
3098 driver->termios_locked = NULL;
3099 }
3100
3101 cdev_init(&driver->cdev, &tty_fops);
3102 driver->cdev.owner = driver->owner;
3103 error = cdev_add(&driver->cdev, dev, driver->num);
3104 if (error) {
3105 cdev_del(&driver->cdev);
3106 unregister_chrdev_region(dev, driver->num);
3107 driver->ttys = NULL;
3108 driver->termios = driver->termios_locked = NULL;
3109 kfree(p);
3110 return error;
3111 }
3112
3113 if (!driver->put_char)
3114 driver->put_char = tty_default_put_char;
3115
3116 list_add(&driver->tty_drivers, &tty_drivers);
3117
3118 if ( !(driver->flags & TTY_DRIVER_NO_DEVFS) ) {
3119 for(i = 0; i < driver->num; i++)
3120 tty_register_device(driver, i, NULL);
3121 }
3122 proc_tty_register_driver(driver);
3123 return 0;
3124}
3125
3126EXPORT_SYMBOL(tty_register_driver);
3127
3128/*
3129 * Called by a tty driver to unregister itself.
3130 */
3131int tty_unregister_driver(struct tty_driver *driver)
3132{
3133 int i;
3134 struct termios *tp;
3135 void *p;
3136
3137 if (driver->refcount)
3138 return -EBUSY;
3139
3140 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3141 driver->num);
3142
3143 list_del(&driver->tty_drivers);
3144
3145 /*
3146 * Free the termios and termios_locked structures because
3147 * we don't want to get memory leaks when modular tty
3148 * drivers are removed from the kernel.
3149 */
3150 for (i = 0; i < driver->num; i++) {
3151 tp = driver->termios[i];
3152 if (tp) {
3153 driver->termios[i] = NULL;
3154 kfree(tp);
3155 }
3156 tp = driver->termios_locked[i];
3157 if (tp) {
3158 driver->termios_locked[i] = NULL;
3159 kfree(tp);
3160 }
3161 if (!(driver->flags & TTY_DRIVER_NO_DEVFS))
3162 tty_unregister_device(driver, i);
3163 }
3164 p = driver->ttys;
3165 proc_tty_unregister_driver(driver);
3166 driver->ttys = NULL;
3167 driver->termios = driver->termios_locked = NULL;
3168 kfree(p);
3169 cdev_del(&driver->cdev);
3170 return 0;
3171}
3172
3173EXPORT_SYMBOL(tty_unregister_driver);
3174
3175
3176/*
3177 * Initialize the console device. This is called *early*, so
3178 * we can't necessarily depend on lots of kernel help here.
3179 * Just do some early initializations, and do the complex setup
3180 * later.
3181 */
3182void __init console_init(void)
3183{
3184 initcall_t *call;
3185
3186 /* Setup the default TTY line discipline. */
3187 (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY);
3188
3189 /*
3190 * set up the console device so that later boot sequences can
3191 * inform about problems etc..
3192 */
3193#ifdef CONFIG_EARLY_PRINTK
3194 disable_early_printk();
1da177e4
LT		 3195#endif
3196 call = __con_initcall_start;
3197 while (call < __con_initcall_end) {
3198 (*call)();
3199 call++;
3200 }
3201}
3202
3203#ifdef CONFIG_VT
3204extern int vty_init(void);
3205#endif
3206
3207static int __init tty_class_init(void)
3208{
7fe845d1 3209 tty_class = class_create(THIS_MODULE, "tty");
1da177e4
LT		 3210 if (IS_ERR(tty_class))
3211 return PTR_ERR(tty_class);
3212 return 0;
3213}
3214
3215postcore_initcall(tty_class_init);
3216
3217/* 3/2004 jmc: why do these devices exist? */
3218
3219static struct cdev tty_cdev, console_cdev;
3220#ifdef CONFIG_UNIX98_PTYS
3221static struct cdev ptmx_cdev;
3222#endif
3223#ifdef CONFIG_VT
3224static struct cdev vc0_cdev;
3225#endif
3226
3227/*
3228 * Ok, now we can initialize the rest of the tty devices and can count
3229 * on memory allocations, interrupts etc..
3230 */
3231static int __init tty_init(void)
3232{
3233 cdev_init(&tty_cdev, &tty_fops);
3234 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3235 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3236 panic("Couldn't register /dev/tty driver\n");
3237 devfs_mk_cdev(MKDEV(TTYAUX_MAJOR, 0), S_IFCHR|S_IRUGO|S_IWUGO, "tty");
53f46542 3238 class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
1da177e4
LT		 3239
3240 cdev_init(&console_cdev, &console_fops);
3241 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3242 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3243 panic("Couldn't register /dev/console driver\n");
3244 devfs_mk_cdev(MKDEV(TTYAUX_MAJOR, 1), S_IFCHR|S_IRUSR|S_IWUSR, "console");
53f46542 3245 class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL, "console");
1da177e4
LT		 3246
3247#ifdef CONFIG_UNIX98_PTYS
3248 cdev_init(&ptmx_cdev, &ptmx_fops);
3249 if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
3250 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
3251 panic("Couldn't register /dev/ptmx driver\n");
3252 devfs_mk_cdev(MKDEV(TTYAUX_MAJOR, 2), S_IFCHR|S_IRUGO|S_IWUGO, "ptmx");
53f46542 3253 class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
1da177e4
LT		 3254#endif
3255
3256#ifdef CONFIG_VT
3257 cdev_init(&vc0_cdev, &console_fops);
3258 if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
3259 register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
3260 panic("Couldn't register /dev/tty0 driver\n");
3261 devfs_mk_cdev(MKDEV(TTY_MAJOR, 0), S_IFCHR|S_IRUSR|S_IWUSR, "vc/0");
53f46542 3262 class_device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0");
1da177e4
LT		 3263
3264 vty_init();
3265#endif
3266 return 0;
3267}
3268module_init(tty_init);
kernel source for telekom puls (alcatel/mediatek)