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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * Copyright (C) 1991, 1992 Linus Torvalds | |
4 | */ | |
5 | ||
6 | /* | |
7 | * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles | |
8 | * or rs-channels. It also implements echoing, cooked mode etc. | |
9 | * | |
10 | * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. | |
11 | * | |
12 | * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the | |
13 | * tty_struct and tty_queue structures. Previously there was an array | |
14 | * of 256 tty_struct's which was statically allocated, and the | |
15 | * tty_queue structures were allocated at boot time. Both are now | |
16 | * dynamically allocated only when the tty is open. | |
17 | * | |
18 | * Also restructured routines so that there is more of a separation | |
19 | * between the high-level tty routines (tty_io.c and tty_ioctl.c) and | |
20 | * the low-level tty routines (serial.c, pty.c, console.c). This | |
21 | * makes for cleaner and more compact code. -TYT, 9/17/92 | |
22 | * | |
23 | * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines | |
24 | * which can be dynamically activated and de-activated by the line | |
25 | * discipline handling modules (like SLIP). | |
26 | * | |
27 | * NOTE: pay no attention to the line discipline code (yet); its | |
28 | * interface is still subject to change in this version... | |
29 | * -- TYT, 1/31/92 | |
30 | * | |
31 | * Added functionality to the OPOST tty handling. No delays, but all | |
32 | * other bits should be there. | |
33 | * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. | |
34 | * | |
35 | * Rewrote canonical mode and added more termios flags. | |
36 | * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 | |
37 | * | |
38 | * Reorganized FASYNC support so mouse code can share it. | |
39 | * -- ctm@ardi.com, 9Sep95 | |
40 | * | |
41 | * New TIOCLINUX variants added. | |
42 | * -- mj@k332.feld.cvut.cz, 19-Nov-95 | |
43 | * | |
44 | * Restrict vt switching via ioctl() | |
45 | * -- grif@cs.ucr.edu, 5-Dec-95 | |
46 | * | |
47 | * Move console and virtual terminal code to more appropriate files, | |
48 | * implement CONFIG_VT and generalize console device interface. | |
49 | * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 | |
50 | * | |
51 | * Rewrote tty_init_dev and tty_release_dev to eliminate races. | |
52 | * -- Bill Hawes <whawes@star.net>, June 97 | |
53 | * | |
54 | * Added devfs support. | |
55 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 | |
56 | * | |
57 | * Added support for a Unix98-style ptmx device. | |
58 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 | |
59 | * | |
60 | * Reduced memory usage for older ARM systems | |
61 | * -- Russell King <rmk@arm.linux.org.uk> | |
62 | * | |
63 | * Move do_SAK() into process context. Less stack use in devfs functions. | |
64 | * alloc_tty_struct() always uses kmalloc() | |
65 | * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 | |
66 | */ | |
67 | ||
68 | #include <linux/types.h> | |
69 | #include <linux/major.h> | |
70 | #include <linux/errno.h> | |
71 | #include <linux/signal.h> | |
72 | #include <linux/fcntl.h> | |
73 | #include <linux/sched/signal.h> | |
74 | #include <linux/sched/task.h> | |
75 | #include <linux/interrupt.h> | |
76 | #include <linux/tty.h> | |
77 | #include <linux/tty_driver.h> | |
78 | #include <linux/tty_flip.h> | |
79 | #include <linux/devpts_fs.h> | |
80 | #include <linux/file.h> | |
81 | #include <linux/fdtable.h> | |
82 | #include <linux/console.h> | |
83 | #include <linux/timer.h> | |
84 | #include <linux/ctype.h> | |
85 | #include <linux/kd.h> | |
86 | #include <linux/mm.h> | |
87 | #include <linux/string.h> | |
88 | #include <linux/slab.h> | |
89 | #include <linux/poll.h> | |
90 | #include <linux/proc_fs.h> | |
91 | #include <linux/init.h> | |
92 | #include <linux/module.h> | |
93 | #include <linux/device.h> | |
94 | #include <linux/wait.h> | |
95 | #include <linux/bitops.h> | |
96 | #include <linux/delay.h> | |
97 | #include <linux/seq_file.h> | |
98 | #include <linux/serial.h> | |
99 | #include <linux/ratelimit.h> | |
100 | ||
101 | #include <linux/uaccess.h> | |
102 | ||
103 | #include <linux/kbd_kern.h> | |
104 | #include <linux/vt_kern.h> | |
105 | #include <linux/selection.h> | |
106 | ||
107 | #include <linux/kmod.h> | |
108 | #include <linux/nsproxy.h> | |
109 | ||
110 | #undef TTY_DEBUG_HANGUP | |
111 | #ifdef TTY_DEBUG_HANGUP | |
112 | # define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args) | |
113 | #else | |
114 | # define tty_debug_hangup(tty, f, args...) do { } while (0) | |
115 | #endif | |
116 | ||
117 | #define TTY_PARANOIA_CHECK 1 | |
118 | #define CHECK_TTY_COUNT 1 | |
119 | ||
120 | struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ | |
121 | .c_iflag = ICRNL | IXON, | |
122 | .c_oflag = OPOST | ONLCR, | |
123 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, | |
124 | .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | | |
125 | ECHOCTL | ECHOKE | IEXTEN, | |
126 | .c_cc = INIT_C_CC, | |
127 | .c_ispeed = 38400, | |
128 | .c_ospeed = 38400, | |
129 | /* .c_line = N_TTY, */ | |
130 | }; | |
131 | ||
132 | EXPORT_SYMBOL(tty_std_termios); | |
133 | ||
134 | /* This list gets poked at by procfs and various bits of boot up code. This | |
135 | could do with some rationalisation such as pulling the tty proc function | |
136 | into this file */ | |
137 | ||
138 | LIST_HEAD(tty_drivers); /* linked list of tty drivers */ | |
139 | ||
140 | /* Mutex to protect creating and releasing a tty */ | |
141 | DEFINE_MUTEX(tty_mutex); | |
142 | ||
143 | static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); | |
144 | static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); | |
145 | ssize_t redirected_tty_write(struct file *, const char __user *, | |
146 | size_t, loff_t *); | |
147 | static __poll_t tty_poll(struct file *, poll_table *); | |
148 | static int tty_open(struct inode *, struct file *); | |
149 | long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg); | |
150 | #ifdef CONFIG_COMPAT | |
151 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, | |
152 | unsigned long arg); | |
153 | #else | |
154 | #define tty_compat_ioctl NULL | |
155 | #endif | |
156 | static int __tty_fasync(int fd, struct file *filp, int on); | |
157 | static int tty_fasync(int fd, struct file *filp, int on); | |
158 | static void release_tty(struct tty_struct *tty, int idx); | |
159 | ||
160 | /** | |
161 | * free_tty_struct - free a disused tty | |
162 | * @tty: tty struct to free | |
163 | * | |
164 | * Free the write buffers, tty queue and tty memory itself. | |
165 | * | |
166 | * Locking: none. Must be called after tty is definitely unused | |
167 | */ | |
168 | ||
169 | static void free_tty_struct(struct tty_struct *tty) | |
170 | { | |
171 | tty_ldisc_deinit(tty); | |
172 | put_device(tty->dev); | |
173 | kfree(tty->write_buf); | |
174 | tty->magic = 0xDEADDEAD; | |
175 | kfree(tty); | |
176 | } | |
177 | ||
178 | static inline struct tty_struct *file_tty(struct file *file) | |
179 | { | |
180 | return ((struct tty_file_private *)file->private_data)->tty; | |
181 | } | |
182 | ||
183 | int tty_alloc_file(struct file *file) | |
184 | { | |
185 | struct tty_file_private *priv; | |
186 | ||
187 | priv = kmalloc(sizeof(*priv), GFP_KERNEL); | |
188 | if (!priv) | |
189 | return -ENOMEM; | |
190 | ||
191 | file->private_data = priv; | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
196 | /* Associate a new file with the tty structure */ | |
197 | void tty_add_file(struct tty_struct *tty, struct file *file) | |
198 | { | |
199 | struct tty_file_private *priv = file->private_data; | |
200 | ||
201 | priv->tty = tty; | |
202 | priv->file = file; | |
203 | ||
204 | spin_lock(&tty->files_lock); | |
205 | list_add(&priv->list, &tty->tty_files); | |
206 | spin_unlock(&tty->files_lock); | |
207 | } | |
208 | ||
209 | /** | |
210 | * tty_free_file - free file->private_data | |
211 | * | |
212 | * This shall be used only for fail path handling when tty_add_file was not | |
213 | * called yet. | |
214 | */ | |
215 | void tty_free_file(struct file *file) | |
216 | { | |
217 | struct tty_file_private *priv = file->private_data; | |
218 | ||
219 | file->private_data = NULL; | |
220 | kfree(priv); | |
221 | } | |
222 | ||
223 | /* Delete file from its tty */ | |
224 | static void tty_del_file(struct file *file) | |
225 | { | |
226 | struct tty_file_private *priv = file->private_data; | |
227 | struct tty_struct *tty = priv->tty; | |
228 | ||
229 | spin_lock(&tty->files_lock); | |
230 | list_del(&priv->list); | |
231 | spin_unlock(&tty->files_lock); | |
232 | tty_free_file(file); | |
233 | } | |
234 | ||
235 | /** | |
236 | * tty_name - return tty naming | |
237 | * @tty: tty structure | |
238 | * | |
239 | * Convert a tty structure into a name. The name reflects the kernel | |
240 | * naming policy and if udev is in use may not reflect user space | |
241 | * | |
242 | * Locking: none | |
243 | */ | |
244 | ||
245 | const char *tty_name(const struct tty_struct *tty) | |
246 | { | |
247 | if (!tty) /* Hmm. NULL pointer. That's fun. */ | |
248 | return "NULL tty"; | |
249 | return tty->name; | |
250 | } | |
251 | ||
252 | EXPORT_SYMBOL(tty_name); | |
253 | ||
254 | const char *tty_driver_name(const struct tty_struct *tty) | |
255 | { | |
256 | if (!tty || !tty->driver) | |
257 | return ""; | |
258 | return tty->driver->name; | |
259 | } | |
260 | ||
261 | static int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, | |
262 | const char *routine) | |
263 | { | |
264 | #ifdef TTY_PARANOIA_CHECK | |
265 | if (!tty) { | |
266 | pr_warn("(%d:%d): %s: NULL tty\n", | |
267 | imajor(inode), iminor(inode), routine); | |
268 | return 1; | |
269 | } | |
270 | if (tty->magic != TTY_MAGIC) { | |
271 | pr_warn("(%d:%d): %s: bad magic number\n", | |
272 | imajor(inode), iminor(inode), routine); | |
273 | return 1; | |
274 | } | |
275 | #endif | |
276 | return 0; | |
277 | } | |
278 | ||
279 | /* Caller must hold tty_lock */ | |
280 | static int check_tty_count(struct tty_struct *tty, const char *routine) | |
281 | { | |
282 | #ifdef CHECK_TTY_COUNT | |
283 | struct list_head *p; | |
284 | int count = 0, kopen_count = 0; | |
285 | ||
286 | spin_lock(&tty->files_lock); | |
287 | list_for_each(p, &tty->tty_files) { | |
288 | count++; | |
289 | } | |
290 | spin_unlock(&tty->files_lock); | |
291 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
292 | tty->driver->subtype == PTY_TYPE_SLAVE && | |
293 | tty->link && tty->link->count) | |
294 | count++; | |
295 | if (tty_port_kopened(tty->port)) | |
296 | kopen_count++; | |
297 | if (tty->count != (count + kopen_count)) { | |
298 | tty_warn(tty, "%s: tty->count(%d) != (#fd's(%d) + #kopen's(%d))\n", | |
299 | routine, tty->count, count, kopen_count); | |
300 | return (count + kopen_count); | |
301 | } | |
302 | #endif | |
303 | return 0; | |
304 | } | |
305 | ||
306 | /** | |
307 | * get_tty_driver - find device of a tty | |
308 | * @dev_t: device identifier | |
309 | * @index: returns the index of the tty | |
310 | * | |
311 | * This routine returns a tty driver structure, given a device number | |
312 | * and also passes back the index number. | |
313 | * | |
314 | * Locking: caller must hold tty_mutex | |
315 | */ | |
316 | ||
317 | static struct tty_driver *get_tty_driver(dev_t device, int *index) | |
318 | { | |
319 | struct tty_driver *p; | |
320 | ||
321 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
322 | dev_t base = MKDEV(p->major, p->minor_start); | |
323 | if (device < base || device >= base + p->num) | |
324 | continue; | |
325 | *index = device - base; | |
326 | return tty_driver_kref_get(p); | |
327 | } | |
328 | return NULL; | |
329 | } | |
330 | ||
331 | /** | |
332 | * tty_dev_name_to_number - return dev_t for device name | |
333 | * @name: user space name of device under /dev | |
334 | * @number: pointer to dev_t that this function will populate | |
335 | * | |
336 | * This function converts device names like ttyS0 or ttyUSB1 into dev_t | |
337 | * like (4, 64) or (188, 1). If no corresponding driver is registered then | |
338 | * the function returns -ENODEV. | |
339 | * | |
340 | * Locking: this acquires tty_mutex to protect the tty_drivers list from | |
341 | * being modified while we are traversing it, and makes sure to | |
342 | * release it before exiting. | |
343 | */ | |
344 | int tty_dev_name_to_number(const char *name, dev_t *number) | |
345 | { | |
346 | struct tty_driver *p; | |
347 | int ret; | |
348 | int index, prefix_length = 0; | |
349 | const char *str; | |
350 | ||
351 | for (str = name; *str && !isdigit(*str); str++) | |
352 | ; | |
353 | ||
354 | if (!*str) | |
355 | return -EINVAL; | |
356 | ||
357 | ret = kstrtoint(str, 10, &index); | |
358 | if (ret) | |
359 | return ret; | |
360 | ||
361 | prefix_length = str - name; | |
362 | mutex_lock(&tty_mutex); | |
363 | ||
364 | list_for_each_entry(p, &tty_drivers, tty_drivers) | |
365 | if (prefix_length == strlen(p->name) && strncmp(name, | |
366 | p->name, prefix_length) == 0) { | |
367 | if (index < p->num) { | |
368 | *number = MKDEV(p->major, p->minor_start + index); | |
369 | goto out; | |
370 | } | |
371 | } | |
372 | ||
373 | /* if here then driver wasn't found */ | |
374 | ret = -ENODEV; | |
375 | out: | |
376 | mutex_unlock(&tty_mutex); | |
377 | return ret; | |
378 | } | |
379 | EXPORT_SYMBOL_GPL(tty_dev_name_to_number); | |
380 | ||
381 | #ifdef CONFIG_CONSOLE_POLL | |
382 | ||
383 | /** | |
384 | * tty_find_polling_driver - find device of a polled tty | |
385 | * @name: name string to match | |
386 | * @line: pointer to resulting tty line nr | |
387 | * | |
388 | * This routine returns a tty driver structure, given a name | |
389 | * and the condition that the tty driver is capable of polled | |
390 | * operation. | |
391 | */ | |
392 | struct tty_driver *tty_find_polling_driver(char *name, int *line) | |
393 | { | |
394 | struct tty_driver *p, *res = NULL; | |
395 | int tty_line = 0; | |
396 | int len; | |
397 | char *str, *stp; | |
398 | ||
399 | for (str = name; *str; str++) | |
400 | if ((*str >= '0' && *str <= '9') || *str == ',') | |
401 | break; | |
402 | if (!*str) | |
403 | return NULL; | |
404 | ||
405 | len = str - name; | |
406 | tty_line = simple_strtoul(str, &str, 10); | |
407 | ||
408 | mutex_lock(&tty_mutex); | |
409 | /* Search through the tty devices to look for a match */ | |
410 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
411 | if (strncmp(name, p->name, len) != 0) | |
412 | continue; | |
413 | stp = str; | |
414 | if (*stp == ',') | |
415 | stp++; | |
416 | if (*stp == '\0') | |
417 | stp = NULL; | |
418 | ||
419 | if (tty_line >= 0 && tty_line < p->num && p->ops && | |
420 | p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) { | |
421 | res = tty_driver_kref_get(p); | |
422 | *line = tty_line; | |
423 | break; | |
424 | } | |
425 | } | |
426 | mutex_unlock(&tty_mutex); | |
427 | ||
428 | return res; | |
429 | } | |
430 | EXPORT_SYMBOL_GPL(tty_find_polling_driver); | |
431 | #endif | |
432 | ||
433 | static ssize_t hung_up_tty_read(struct file *file, char __user *buf, | |
434 | size_t count, loff_t *ppos) | |
435 | { | |
436 | return 0; | |
437 | } | |
438 | ||
439 | static ssize_t hung_up_tty_write(struct file *file, const char __user *buf, | |
440 | size_t count, loff_t *ppos) | |
441 | { | |
442 | return -EIO; | |
443 | } | |
444 | ||
445 | /* No kernel lock held - none needed ;) */ | |
446 | static __poll_t hung_up_tty_poll(struct file *filp, poll_table *wait) | |
447 | { | |
448 | return EPOLLIN | EPOLLOUT | EPOLLERR | EPOLLHUP | EPOLLRDNORM | EPOLLWRNORM; | |
449 | } | |
450 | ||
451 | static long hung_up_tty_ioctl(struct file *file, unsigned int cmd, | |
452 | unsigned long arg) | |
453 | { | |
454 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
455 | } | |
456 | ||
457 | static long hung_up_tty_compat_ioctl(struct file *file, | |
458 | unsigned int cmd, unsigned long arg) | |
459 | { | |
460 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
461 | } | |
462 | ||
463 | static int hung_up_tty_fasync(int fd, struct file *file, int on) | |
464 | { | |
465 | return -ENOTTY; | |
466 | } | |
467 | ||
468 | static void tty_show_fdinfo(struct seq_file *m, struct file *file) | |
469 | { | |
470 | struct tty_struct *tty = file_tty(file); | |
471 | ||
472 | if (tty && tty->ops && tty->ops->show_fdinfo) | |
473 | tty->ops->show_fdinfo(tty, m); | |
474 | } | |
475 | ||
476 | static const struct file_operations tty_fops = { | |
477 | .llseek = no_llseek, | |
478 | .read = tty_read, | |
479 | .write = tty_write, | |
480 | .poll = tty_poll, | |
481 | .unlocked_ioctl = tty_ioctl, | |
482 | .compat_ioctl = tty_compat_ioctl, | |
483 | .open = tty_open, | |
484 | .release = tty_release, | |
485 | .fasync = tty_fasync, | |
486 | .show_fdinfo = tty_show_fdinfo, | |
487 | }; | |
488 | ||
489 | static const struct file_operations console_fops = { | |
490 | .llseek = no_llseek, | |
491 | .read = tty_read, | |
492 | .write = redirected_tty_write, | |
493 | .poll = tty_poll, | |
494 | .unlocked_ioctl = tty_ioctl, | |
495 | .compat_ioctl = tty_compat_ioctl, | |
496 | .open = tty_open, | |
497 | .release = tty_release, | |
498 | .fasync = tty_fasync, | |
499 | }; | |
500 | ||
501 | static const struct file_operations hung_up_tty_fops = { | |
502 | .llseek = no_llseek, | |
503 | .read = hung_up_tty_read, | |
504 | .write = hung_up_tty_write, | |
505 | .poll = hung_up_tty_poll, | |
506 | .unlocked_ioctl = hung_up_tty_ioctl, | |
507 | .compat_ioctl = hung_up_tty_compat_ioctl, | |
508 | .release = tty_release, | |
509 | .fasync = hung_up_tty_fasync, | |
510 | }; | |
511 | ||
512 | static DEFINE_SPINLOCK(redirect_lock); | |
513 | static struct file *redirect; | |
514 | ||
515 | /** | |
516 | * tty_wakeup - request more data | |
517 | * @tty: terminal | |
518 | * | |
519 | * Internal and external helper for wakeups of tty. This function | |
520 | * informs the line discipline if present that the driver is ready | |
521 | * to receive more output data. | |
522 | */ | |
523 | ||
524 | void tty_wakeup(struct tty_struct *tty) | |
525 | { | |
526 | struct tty_ldisc *ld; | |
527 | ||
528 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { | |
529 | ld = tty_ldisc_ref(tty); | |
530 | if (ld) { | |
531 | if (ld->ops->write_wakeup) | |
532 | ld->ops->write_wakeup(tty); | |
533 | tty_ldisc_deref(ld); | |
534 | } | |
535 | } | |
536 | wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT); | |
537 | } | |
538 | ||
539 | EXPORT_SYMBOL_GPL(tty_wakeup); | |
540 | ||
541 | /** | |
542 | * __tty_hangup - actual handler for hangup events | |
543 | * @work: tty device | |
544 | * | |
545 | * This can be called by a "kworker" kernel thread. That is process | |
546 | * synchronous but doesn't hold any locks, so we need to make sure we | |
547 | * have the appropriate locks for what we're doing. | |
548 | * | |
549 | * The hangup event clears any pending redirections onto the hung up | |
550 | * device. It ensures future writes will error and it does the needed | |
551 | * line discipline hangup and signal delivery. The tty object itself | |
552 | * remains intact. | |
553 | * | |
554 | * Locking: | |
555 | * BTM | |
556 | * redirect lock for undoing redirection | |
557 | * file list lock for manipulating list of ttys | |
558 | * tty_ldiscs_lock from called functions | |
559 | * termios_rwsem resetting termios data | |
560 | * tasklist_lock to walk task list for hangup event | |
561 | * ->siglock to protect ->signal/->sighand | |
562 | */ | |
563 | static void __tty_hangup(struct tty_struct *tty, int exit_session) | |
564 | { | |
565 | struct file *cons_filp = NULL; | |
566 | struct file *filp, *f = NULL; | |
567 | struct tty_file_private *priv; | |
568 | int closecount = 0, n; | |
569 | int refs; | |
570 | ||
571 | if (!tty) | |
572 | return; | |
573 | ||
574 | ||
575 | spin_lock(&redirect_lock); | |
576 | if (redirect && file_tty(redirect) == tty) { | |
577 | f = redirect; | |
578 | redirect = NULL; | |
579 | } | |
580 | spin_unlock(&redirect_lock); | |
581 | ||
582 | tty_lock(tty); | |
583 | ||
584 | if (test_bit(TTY_HUPPED, &tty->flags)) { | |
585 | tty_unlock(tty); | |
586 | return; | |
587 | } | |
588 | ||
589 | /* | |
590 | * Some console devices aren't actually hung up for technical and | |
591 | * historical reasons, which can lead to indefinite interruptible | |
592 | * sleep in n_tty_read(). The following explicitly tells | |
593 | * n_tty_read() to abort readers. | |
594 | */ | |
595 | set_bit(TTY_HUPPING, &tty->flags); | |
596 | ||
597 | /* inuse_filps is protected by the single tty lock, | |
598 | this really needs to change if we want to flush the | |
599 | workqueue with the lock held */ | |
600 | check_tty_count(tty, "tty_hangup"); | |
601 | ||
602 | spin_lock(&tty->files_lock); | |
603 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ | |
604 | list_for_each_entry(priv, &tty->tty_files, list) { | |
605 | filp = priv->file; | |
606 | if (filp->f_op->write == redirected_tty_write) | |
607 | cons_filp = filp; | |
608 | if (filp->f_op->write != tty_write) | |
609 | continue; | |
610 | closecount++; | |
611 | __tty_fasync(-1, filp, 0); /* can't block */ | |
612 | filp->f_op = &hung_up_tty_fops; | |
613 | } | |
614 | spin_unlock(&tty->files_lock); | |
615 | ||
616 | refs = tty_signal_session_leader(tty, exit_session); | |
617 | /* Account for the p->signal references we killed */ | |
618 | while (refs--) | |
619 | tty_kref_put(tty); | |
620 | ||
621 | tty_ldisc_hangup(tty, cons_filp != NULL); | |
622 | ||
623 | spin_lock_irq(&tty->ctrl_lock); | |
624 | clear_bit(TTY_THROTTLED, &tty->flags); | |
625 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); | |
626 | put_pid(tty->session); | |
627 | put_pid(tty->pgrp); | |
628 | tty->session = NULL; | |
629 | tty->pgrp = NULL; | |
630 | tty->ctrl_status = 0; | |
631 | spin_unlock_irq(&tty->ctrl_lock); | |
632 | ||
633 | /* | |
634 | * If one of the devices matches a console pointer, we | |
635 | * cannot just call hangup() because that will cause | |
636 | * tty->count and state->count to go out of sync. | |
637 | * So we just call close() the right number of times. | |
638 | */ | |
639 | if (cons_filp) { | |
640 | if (tty->ops->close) | |
641 | for (n = 0; n < closecount; n++) | |
642 | tty->ops->close(tty, cons_filp); | |
643 | } else if (tty->ops->hangup) | |
644 | tty->ops->hangup(tty); | |
645 | /* | |
646 | * We don't want to have driver/ldisc interactions beyond the ones | |
647 | * we did here. The driver layer expects no calls after ->hangup() | |
648 | * from the ldisc side, which is now guaranteed. | |
649 | */ | |
650 | set_bit(TTY_HUPPED, &tty->flags); | |
651 | clear_bit(TTY_HUPPING, &tty->flags); | |
652 | tty_unlock(tty); | |
653 | ||
654 | if (f) | |
655 | fput(f); | |
656 | } | |
657 | ||
658 | static void do_tty_hangup(struct work_struct *work) | |
659 | { | |
660 | struct tty_struct *tty = | |
661 | container_of(work, struct tty_struct, hangup_work); | |
662 | ||
663 | __tty_hangup(tty, 0); | |
664 | } | |
665 | ||
666 | /** | |
667 | * tty_hangup - trigger a hangup event | |
668 | * @tty: tty to hangup | |
669 | * | |
670 | * A carrier loss (virtual or otherwise) has occurred on this like | |
671 | * schedule a hangup sequence to run after this event. | |
672 | */ | |
673 | ||
674 | void tty_hangup(struct tty_struct *tty) | |
675 | { | |
676 | tty_debug_hangup(tty, "hangup\n"); | |
677 | schedule_work(&tty->hangup_work); | |
678 | } | |
679 | ||
680 | EXPORT_SYMBOL(tty_hangup); | |
681 | ||
682 | /** | |
683 | * tty_vhangup - process vhangup | |
684 | * @tty: tty to hangup | |
685 | * | |
686 | * The user has asked via system call for the terminal to be hung up. | |
687 | * We do this synchronously so that when the syscall returns the process | |
688 | * is complete. That guarantee is necessary for security reasons. | |
689 | */ | |
690 | ||
691 | void tty_vhangup(struct tty_struct *tty) | |
692 | { | |
693 | tty_debug_hangup(tty, "vhangup\n"); | |
694 | __tty_hangup(tty, 0); | |
695 | } | |
696 | ||
697 | EXPORT_SYMBOL(tty_vhangup); | |
698 | ||
699 | ||
700 | /** | |
701 | * tty_vhangup_self - process vhangup for own ctty | |
702 | * | |
703 | * Perform a vhangup on the current controlling tty | |
704 | */ | |
705 | ||
706 | void tty_vhangup_self(void) | |
707 | { | |
708 | struct tty_struct *tty; | |
709 | ||
710 | tty = get_current_tty(); | |
711 | if (tty) { | |
712 | tty_vhangup(tty); | |
713 | tty_kref_put(tty); | |
714 | } | |
715 | } | |
716 | ||
717 | /** | |
718 | * tty_vhangup_session - hangup session leader exit | |
719 | * @tty: tty to hangup | |
720 | * | |
721 | * The session leader is exiting and hanging up its controlling terminal. | |
722 | * Every process in the foreground process group is signalled SIGHUP. | |
723 | * | |
724 | * We do this synchronously so that when the syscall returns the process | |
725 | * is complete. That guarantee is necessary for security reasons. | |
726 | */ | |
727 | ||
728 | void tty_vhangup_session(struct tty_struct *tty) | |
729 | { | |
730 | tty_debug_hangup(tty, "session hangup\n"); | |
731 | __tty_hangup(tty, 1); | |
732 | } | |
733 | ||
734 | /** | |
735 | * tty_hung_up_p - was tty hung up | |
736 | * @filp: file pointer of tty | |
737 | * | |
738 | * Return true if the tty has been subject to a vhangup or a carrier | |
739 | * loss | |
740 | */ | |
741 | ||
742 | int tty_hung_up_p(struct file *filp) | |
743 | { | |
744 | return (filp && filp->f_op == &hung_up_tty_fops); | |
745 | } | |
746 | ||
747 | EXPORT_SYMBOL(tty_hung_up_p); | |
748 | ||
749 | /** | |
750 | * stop_tty - propagate flow control | |
751 | * @tty: tty to stop | |
752 | * | |
753 | * Perform flow control to the driver. May be called | |
754 | * on an already stopped device and will not re-call the driver | |
755 | * method. | |
756 | * | |
757 | * This functionality is used by both the line disciplines for | |
758 | * halting incoming flow and by the driver. It may therefore be | |
759 | * called from any context, may be under the tty atomic_write_lock | |
760 | * but not always. | |
761 | * | |
762 | * Locking: | |
763 | * flow_lock | |
764 | */ | |
765 | ||
766 | void __stop_tty(struct tty_struct *tty) | |
767 | { | |
768 | if (tty->stopped) | |
769 | return; | |
770 | tty->stopped = 1; | |
771 | if (tty->ops->stop) | |
772 | tty->ops->stop(tty); | |
773 | } | |
774 | ||
775 | void stop_tty(struct tty_struct *tty) | |
776 | { | |
777 | unsigned long flags; | |
778 | ||
779 | spin_lock_irqsave(&tty->flow_lock, flags); | |
780 | __stop_tty(tty); | |
781 | spin_unlock_irqrestore(&tty->flow_lock, flags); | |
782 | } | |
783 | EXPORT_SYMBOL(stop_tty); | |
784 | ||
785 | /** | |
786 | * start_tty - propagate flow control | |
787 | * @tty: tty to start | |
788 | * | |
789 | * Start a tty that has been stopped if at all possible. If this | |
790 | * tty was previous stopped and is now being started, the driver | |
791 | * start method is invoked and the line discipline woken. | |
792 | * | |
793 | * Locking: | |
794 | * flow_lock | |
795 | */ | |
796 | ||
797 | void __start_tty(struct tty_struct *tty) | |
798 | { | |
799 | if (!tty->stopped || tty->flow_stopped) | |
800 | return; | |
801 | tty->stopped = 0; | |
802 | if (tty->ops->start) | |
803 | tty->ops->start(tty); | |
804 | tty_wakeup(tty); | |
805 | } | |
806 | ||
807 | void start_tty(struct tty_struct *tty) | |
808 | { | |
809 | unsigned long flags; | |
810 | ||
811 | spin_lock_irqsave(&tty->flow_lock, flags); | |
812 | __start_tty(tty); | |
813 | spin_unlock_irqrestore(&tty->flow_lock, flags); | |
814 | } | |
815 | EXPORT_SYMBOL(start_tty); | |
816 | ||
817 | static void tty_update_time(struct timespec *time) | |
818 | { | |
819 | unsigned long sec = get_seconds(); | |
820 | ||
821 | /* | |
822 | * We only care if the two values differ in anything other than the | |
823 | * lower three bits (i.e every 8 seconds). If so, then we can update | |
824 | * the time of the tty device, otherwise it could be construded as a | |
825 | * security leak to let userspace know the exact timing of the tty. | |
826 | */ | |
827 | if ((sec ^ time->tv_sec) & ~7) | |
828 | time->tv_sec = sec; | |
829 | } | |
830 | ||
831 | /** | |
832 | * tty_read - read method for tty device files | |
833 | * @file: pointer to tty file | |
834 | * @buf: user buffer | |
835 | * @count: size of user buffer | |
836 | * @ppos: unused | |
837 | * | |
838 | * Perform the read system call function on this terminal device. Checks | |
839 | * for hung up devices before calling the line discipline method. | |
840 | * | |
841 | * Locking: | |
842 | * Locks the line discipline internally while needed. Multiple | |
843 | * read calls may be outstanding in parallel. | |
844 | */ | |
845 | ||
846 | static ssize_t tty_read(struct file *file, char __user *buf, size_t count, | |
847 | loff_t *ppos) | |
848 | { | |
849 | int i; | |
850 | struct inode *inode = file_inode(file); | |
851 | struct tty_struct *tty = file_tty(file); | |
852 | struct tty_ldisc *ld; | |
853 | ||
854 | if (tty_paranoia_check(tty, inode, "tty_read")) | |
855 | return -EIO; | |
856 | if (!tty || tty_io_error(tty)) | |
857 | return -EIO; | |
858 | ||
859 | /* We want to wait for the line discipline to sort out in this | |
860 | situation */ | |
861 | ld = tty_ldisc_ref_wait(tty); | |
862 | if (!ld) | |
863 | return hung_up_tty_read(file, buf, count, ppos); | |
864 | if (ld->ops->read) | |
865 | i = ld->ops->read(tty, file, buf, count); | |
866 | else | |
867 | i = -EIO; | |
868 | tty_ldisc_deref(ld); | |
869 | ||
870 | if (i > 0) | |
871 | tty_update_time(&inode->i_atime); | |
872 | ||
873 | return i; | |
874 | } | |
875 | ||
876 | static void tty_write_unlock(struct tty_struct *tty) | |
877 | { | |
878 | mutex_unlock(&tty->atomic_write_lock); | |
879 | wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT); | |
880 | } | |
881 | ||
882 | static int tty_write_lock(struct tty_struct *tty, int ndelay) | |
883 | { | |
884 | if (!mutex_trylock(&tty->atomic_write_lock)) { | |
885 | if (ndelay) | |
886 | return -EAGAIN; | |
887 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) | |
888 | return -ERESTARTSYS; | |
889 | } | |
890 | return 0; | |
891 | } | |
892 | ||
893 | /* | |
894 | * Split writes up in sane blocksizes to avoid | |
895 | * denial-of-service type attacks | |
896 | */ | |
897 | static inline ssize_t do_tty_write( | |
898 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
899 | struct tty_struct *tty, | |
900 | struct file *file, | |
901 | const char __user *buf, | |
902 | size_t count) | |
903 | { | |
904 | ssize_t ret, written = 0; | |
905 | unsigned int chunk; | |
906 | ||
907 | ret = tty_write_lock(tty, file->f_flags & O_NDELAY); | |
908 | if (ret < 0) | |
909 | return ret; | |
910 | ||
911 | /* | |
912 | * We chunk up writes into a temporary buffer. This | |
913 | * simplifies low-level drivers immensely, since they | |
914 | * don't have locking issues and user mode accesses. | |
915 | * | |
916 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
917 | * big chunk-size.. | |
918 | * | |
919 | * The default chunk-size is 2kB, because the NTTY | |
920 | * layer has problems with bigger chunks. It will | |
921 | * claim to be able to handle more characters than | |
922 | * it actually does. | |
923 | * | |
924 | * FIXME: This can probably go away now except that 64K chunks | |
925 | * are too likely to fail unless switched to vmalloc... | |
926 | */ | |
927 | chunk = 2048; | |
928 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
929 | chunk = 65536; | |
930 | if (count < chunk) | |
931 | chunk = count; | |
932 | ||
933 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ | |
934 | if (tty->write_cnt < chunk) { | |
935 | unsigned char *buf_chunk; | |
936 | ||
937 | if (chunk < 1024) | |
938 | chunk = 1024; | |
939 | ||
940 | buf_chunk = kmalloc(chunk, GFP_KERNEL); | |
941 | if (!buf_chunk) { | |
942 | ret = -ENOMEM; | |
943 | goto out; | |
944 | } | |
945 | kfree(tty->write_buf); | |
946 | tty->write_cnt = chunk; | |
947 | tty->write_buf = buf_chunk; | |
948 | } | |
949 | ||
950 | /* Do the write .. */ | |
951 | for (;;) { | |
952 | size_t size = count; | |
953 | if (size > chunk) | |
954 | size = chunk; | |
955 | ret = -EFAULT; | |
956 | if (copy_from_user(tty->write_buf, buf, size)) | |
957 | break; | |
958 | ret = write(tty, file, tty->write_buf, size); | |
959 | if (ret <= 0) | |
960 | break; | |
961 | written += ret; | |
962 | buf += ret; | |
963 | count -= ret; | |
964 | if (!count) | |
965 | break; | |
966 | ret = -ERESTARTSYS; | |
967 | if (signal_pending(current)) | |
968 | break; | |
969 | cond_resched(); | |
970 | } | |
971 | if (written) { | |
972 | tty_update_time(&file_inode(file)->i_mtime); | |
973 | ret = written; | |
974 | } | |
975 | out: | |
976 | tty_write_unlock(tty); | |
977 | return ret; | |
978 | } | |
979 | ||
980 | /** | |
981 | * tty_write_message - write a message to a certain tty, not just the console. | |
982 | * @tty: the destination tty_struct | |
983 | * @msg: the message to write | |
984 | * | |
985 | * This is used for messages that need to be redirected to a specific tty. | |
986 | * We don't put it into the syslog queue right now maybe in the future if | |
987 | * really needed. | |
988 | * | |
989 | * We must still hold the BTM and test the CLOSING flag for the moment. | |
990 | */ | |
991 | ||
992 | void tty_write_message(struct tty_struct *tty, char *msg) | |
993 | { | |
994 | if (tty) { | |
995 | mutex_lock(&tty->atomic_write_lock); | |
996 | tty_lock(tty); | |
997 | if (tty->ops->write && tty->count > 0) | |
998 | tty->ops->write(tty, msg, strlen(msg)); | |
999 | tty_unlock(tty); | |
1000 | tty_write_unlock(tty); | |
1001 | } | |
1002 | return; | |
1003 | } | |
1004 | ||
1005 | ||
1006 | /** | |
1007 | * tty_write - write method for tty device file | |
1008 | * @file: tty file pointer | |
1009 | * @buf: user data to write | |
1010 | * @count: bytes to write | |
1011 | * @ppos: unused | |
1012 | * | |
1013 | * Write data to a tty device via the line discipline. | |
1014 | * | |
1015 | * Locking: | |
1016 | * Locks the line discipline as required | |
1017 | * Writes to the tty driver are serialized by the atomic_write_lock | |
1018 | * and are then processed in chunks to the device. The line discipline | |
1019 | * write method will not be invoked in parallel for each device. | |
1020 | */ | |
1021 | ||
1022 | static ssize_t tty_write(struct file *file, const char __user *buf, | |
1023 | size_t count, loff_t *ppos) | |
1024 | { | |
1025 | struct tty_struct *tty = file_tty(file); | |
1026 | struct tty_ldisc *ld; | |
1027 | ssize_t ret; | |
1028 | ||
1029 | if (tty_paranoia_check(tty, file_inode(file), "tty_write")) | |
1030 | return -EIO; | |
1031 | if (!tty || !tty->ops->write || tty_io_error(tty)) | |
1032 | return -EIO; | |
1033 | /* Short term debug to catch buggy drivers */ | |
1034 | if (tty->ops->write_room == NULL) | |
1035 | tty_err(tty, "missing write_room method\n"); | |
1036 | ld = tty_ldisc_ref_wait(tty); | |
1037 | if (!ld) | |
1038 | return hung_up_tty_write(file, buf, count, ppos); | |
1039 | if (!ld->ops->write) | |
1040 | ret = -EIO; | |
1041 | else | |
1042 | ret = do_tty_write(ld->ops->write, tty, file, buf, count); | |
1043 | tty_ldisc_deref(ld); | |
1044 | return ret; | |
1045 | } | |
1046 | ||
1047 | ssize_t redirected_tty_write(struct file *file, const char __user *buf, | |
1048 | size_t count, loff_t *ppos) | |
1049 | { | |
1050 | struct file *p = NULL; | |
1051 | ||
1052 | spin_lock(&redirect_lock); | |
1053 | if (redirect) | |
1054 | p = get_file(redirect); | |
1055 | spin_unlock(&redirect_lock); | |
1056 | ||
1057 | if (p) { | |
1058 | ssize_t res; | |
1059 | res = vfs_write(p, buf, count, &p->f_pos); | |
1060 | fput(p); | |
1061 | return res; | |
1062 | } | |
1063 | return tty_write(file, buf, count, ppos); | |
1064 | } | |
1065 | ||
1066 | /** | |
1067 | * tty_send_xchar - send priority character | |
1068 | * | |
1069 | * Send a high priority character to the tty even if stopped | |
1070 | * | |
1071 | * Locking: none for xchar method, write ordering for write method. | |
1072 | */ | |
1073 | ||
1074 | int tty_send_xchar(struct tty_struct *tty, char ch) | |
1075 | { | |
1076 | int was_stopped = tty->stopped; | |
1077 | ||
1078 | if (tty->ops->send_xchar) { | |
1079 | down_read(&tty->termios_rwsem); | |
1080 | tty->ops->send_xchar(tty, ch); | |
1081 | up_read(&tty->termios_rwsem); | |
1082 | return 0; | |
1083 | } | |
1084 | ||
1085 | if (tty_write_lock(tty, 0) < 0) | |
1086 | return -ERESTARTSYS; | |
1087 | ||
1088 | down_read(&tty->termios_rwsem); | |
1089 | if (was_stopped) | |
1090 | start_tty(tty); | |
1091 | tty->ops->write(tty, &ch, 1); | |
1092 | if (was_stopped) | |
1093 | stop_tty(tty); | |
1094 | up_read(&tty->termios_rwsem); | |
1095 | tty_write_unlock(tty); | |
1096 | return 0; | |
1097 | } | |
1098 | ||
1099 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
1100 | ||
1101 | /** | |
1102 | * pty_line_name - generate name for a pty | |
1103 | * @driver: the tty driver in use | |
1104 | * @index: the minor number | |
1105 | * @p: output buffer of at least 6 bytes | |
1106 | * | |
1107 | * Generate a name from a driver reference and write it to the output | |
1108 | * buffer. | |
1109 | * | |
1110 | * Locking: None | |
1111 | */ | |
1112 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1113 | { | |
1114 | int i = index + driver->name_base; | |
1115 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
1116 | sprintf(p, "%s%c%x", | |
1117 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, | |
1118 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1119 | } | |
1120 | ||
1121 | /** | |
1122 | * tty_line_name - generate name for a tty | |
1123 | * @driver: the tty driver in use | |
1124 | * @index: the minor number | |
1125 | * @p: output buffer of at least 7 bytes | |
1126 | * | |
1127 | * Generate a name from a driver reference and write it to the output | |
1128 | * buffer. | |
1129 | * | |
1130 | * Locking: None | |
1131 | */ | |
1132 | static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p) | |
1133 | { | |
1134 | if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE) | |
1135 | return sprintf(p, "%s", driver->name); | |
1136 | else | |
1137 | return sprintf(p, "%s%d", driver->name, | |
1138 | index + driver->name_base); | |
1139 | } | |
1140 | ||
1141 | /** | |
1142 | * tty_driver_lookup_tty() - find an existing tty, if any | |
1143 | * @driver: the driver for the tty | |
1144 | * @idx: the minor number | |
1145 | * | |
1146 | * Return the tty, if found. If not found, return NULL or ERR_PTR() if the | |
1147 | * driver lookup() method returns an error. | |
1148 | * | |
1149 | * Locking: tty_mutex must be held. If the tty is found, bump the tty kref. | |
1150 | */ | |
1151 | static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, | |
1152 | struct file *file, int idx) | |
1153 | { | |
1154 | struct tty_struct *tty; | |
1155 | ||
1156 | if (driver->ops->lookup) | |
1157 | if (!file) | |
1158 | tty = ERR_PTR(-EIO); | |
1159 | else | |
1160 | tty = driver->ops->lookup(driver, file, idx); | |
1161 | else | |
1162 | tty = driver->ttys[idx]; | |
1163 | ||
1164 | if (!IS_ERR(tty)) | |
1165 | tty_kref_get(tty); | |
1166 | return tty; | |
1167 | } | |
1168 | ||
1169 | /** | |
1170 | * tty_init_termios - helper for termios setup | |
1171 | * @tty: the tty to set up | |
1172 | * | |
1173 | * Initialise the termios structures for this tty. Thus runs under | |
1174 | * the tty_mutex currently so we can be relaxed about ordering. | |
1175 | */ | |
1176 | ||
1177 | void tty_init_termios(struct tty_struct *tty) | |
1178 | { | |
1179 | struct ktermios *tp; | |
1180 | int idx = tty->index; | |
1181 | ||
1182 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
1183 | tty->termios = tty->driver->init_termios; | |
1184 | else { | |
1185 | /* Check for lazy saved data */ | |
1186 | tp = tty->driver->termios[idx]; | |
1187 | if (tp != NULL) { | |
1188 | tty->termios = *tp; | |
1189 | tty->termios.c_line = tty->driver->init_termios.c_line; | |
1190 | } else | |
1191 | tty->termios = tty->driver->init_termios; | |
1192 | } | |
1193 | /* Compatibility until drivers always set this */ | |
1194 | tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios); | |
1195 | tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios); | |
1196 | } | |
1197 | EXPORT_SYMBOL_GPL(tty_init_termios); | |
1198 | ||
1199 | int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty) | |
1200 | { | |
1201 | tty_init_termios(tty); | |
1202 | tty_driver_kref_get(driver); | |
1203 | tty->count++; | |
1204 | driver->ttys[tty->index] = tty; | |
1205 | return 0; | |
1206 | } | |
1207 | EXPORT_SYMBOL_GPL(tty_standard_install); | |
1208 | ||
1209 | /** | |
1210 | * tty_driver_install_tty() - install a tty entry in the driver | |
1211 | * @driver: the driver for the tty | |
1212 | * @tty: the tty | |
1213 | * | |
1214 | * Install a tty object into the driver tables. The tty->index field | |
1215 | * will be set by the time this is called. This method is responsible | |
1216 | * for ensuring any need additional structures are allocated and | |
1217 | * configured. | |
1218 | * | |
1219 | * Locking: tty_mutex for now | |
1220 | */ | |
1221 | static int tty_driver_install_tty(struct tty_driver *driver, | |
1222 | struct tty_struct *tty) | |
1223 | { | |
1224 | return driver->ops->install ? driver->ops->install(driver, tty) : | |
1225 | tty_standard_install(driver, tty); | |
1226 | } | |
1227 | ||
1228 | /** | |
1229 | * tty_driver_remove_tty() - remove a tty from the driver tables | |
1230 | * @driver: the driver for the tty | |
1231 | * @idx: the minor number | |
1232 | * | |
1233 | * Remvoe a tty object from the driver tables. The tty->index field | |
1234 | * will be set by the time this is called. | |
1235 | * | |
1236 | * Locking: tty_mutex for now | |
1237 | */ | |
1238 | static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty) | |
1239 | { | |
1240 | if (driver->ops->remove) | |
1241 | driver->ops->remove(driver, tty); | |
1242 | else | |
1243 | driver->ttys[tty->index] = NULL; | |
1244 | } | |
1245 | ||
1246 | /* | |
1247 | * tty_reopen() - fast re-open of an open tty | |
1248 | * @tty - the tty to open | |
1249 | * | |
1250 | * Return 0 on success, -errno on error. | |
1251 | * Re-opens on master ptys are not allowed and return -EIO. | |
1252 | * | |
1253 | * Locking: Caller must hold tty_lock | |
1254 | */ | |
1255 | static int tty_reopen(struct tty_struct *tty) | |
1256 | { | |
1257 | struct tty_driver *driver = tty->driver; | |
1258 | ||
1259 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
1260 | driver->subtype == PTY_TYPE_MASTER) | |
1261 | return -EIO; | |
1262 | ||
1263 | if (!tty->count) | |
1264 | return -EAGAIN; | |
1265 | ||
1266 | if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) | |
1267 | return -EBUSY; | |
1268 | ||
1269 | tty->count++; | |
1270 | ||
1271 | if (!tty->ldisc) | |
1272 | return tty_ldisc_reinit(tty, tty->termios.c_line); | |
1273 | ||
1274 | return 0; | |
1275 | } | |
1276 | ||
1277 | /** | |
1278 | * tty_init_dev - initialise a tty device | |
1279 | * @driver: tty driver we are opening a device on | |
1280 | * @idx: device index | |
1281 | * @ret_tty: returned tty structure | |
1282 | * | |
1283 | * Prepare a tty device. This may not be a "new" clean device but | |
1284 | * could also be an active device. The pty drivers require special | |
1285 | * handling because of this. | |
1286 | * | |
1287 | * Locking: | |
1288 | * The function is called under the tty_mutex, which | |
1289 | * protects us from the tty struct or driver itself going away. | |
1290 | * | |
1291 | * On exit the tty device has the line discipline attached and | |
1292 | * a reference count of 1. If a pair was created for pty/tty use | |
1293 | * and the other was a pty master then it too has a reference count of 1. | |
1294 | * | |
1295 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a | |
1296 | * failed open. The new code protects the open with a mutex, so it's | |
1297 | * really quite straightforward. The mutex locking can probably be | |
1298 | * relaxed for the (most common) case of reopening a tty. | |
1299 | */ | |
1300 | ||
1301 | struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) | |
1302 | { | |
1303 | struct tty_struct *tty; | |
1304 | int retval; | |
1305 | ||
1306 | /* | |
1307 | * First time open is complex, especially for PTY devices. | |
1308 | * This code guarantees that either everything succeeds and the | |
1309 | * TTY is ready for operation, or else the table slots are vacated | |
1310 | * and the allocated memory released. (Except that the termios | |
1311 | * may be retained.) | |
1312 | */ | |
1313 | ||
1314 | if (!try_module_get(driver->owner)) | |
1315 | return ERR_PTR(-ENODEV); | |
1316 | ||
1317 | tty = alloc_tty_struct(driver, idx); | |
1318 | if (!tty) { | |
1319 | retval = -ENOMEM; | |
1320 | goto err_module_put; | |
1321 | } | |
1322 | ||
1323 | tty_lock(tty); | |
1324 | retval = tty_driver_install_tty(driver, tty); | |
1325 | if (retval < 0) | |
1326 | goto err_free_tty; | |
1327 | ||
1328 | if (!tty->port) | |
1329 | tty->port = driver->ports[idx]; | |
1330 | ||
1331 | WARN_RATELIMIT(!tty->port, | |
1332 | "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n", | |
1333 | __func__, tty->driver->name); | |
1334 | ||
1335 | retval = tty_ldisc_lock(tty, 5 * HZ); | |
1336 | if (retval) | |
1337 | goto err_release_lock; | |
1338 | tty->port->itty = tty; | |
1339 | ||
1340 | /* | |
1341 | * Structures all installed ... call the ldisc open routines. | |
1342 | * If we fail here just call release_tty to clean up. No need | |
1343 | * to decrement the use counts, as release_tty doesn't care. | |
1344 | */ | |
1345 | retval = tty_ldisc_setup(tty, tty->link); | |
1346 | if (retval) | |
1347 | goto err_release_tty; | |
1348 | tty_ldisc_unlock(tty); | |
1349 | /* Return the tty locked so that it cannot vanish under the caller */ | |
1350 | return tty; | |
1351 | ||
1352 | err_free_tty: | |
1353 | tty_unlock(tty); | |
1354 | free_tty_struct(tty); | |
1355 | err_module_put: | |
1356 | module_put(driver->owner); | |
1357 | return ERR_PTR(retval); | |
1358 | ||
1359 | /* call the tty release_tty routine to clean out this slot */ | |
1360 | err_release_tty: | |
1361 | tty_ldisc_unlock(tty); | |
1362 | tty_info_ratelimited(tty, "ldisc open failed (%d), clearing slot %d\n", | |
1363 | retval, idx); | |
1364 | err_release_lock: | |
1365 | tty_unlock(tty); | |
1366 | release_tty(tty, idx); | |
1367 | return ERR_PTR(retval); | |
1368 | } | |
1369 | ||
1370 | static void tty_free_termios(struct tty_struct *tty) | |
1371 | { | |
1372 | struct ktermios *tp; | |
1373 | int idx = tty->index; | |
1374 | ||
1375 | /* If the port is going to reset then it has no termios to save */ | |
1376 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
1377 | return; | |
1378 | ||
1379 | /* Stash the termios data */ | |
1380 | tp = tty->driver->termios[idx]; | |
1381 | if (tp == NULL) { | |
1382 | tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); | |
1383 | if (tp == NULL) | |
1384 | return; | |
1385 | tty->driver->termios[idx] = tp; | |
1386 | } | |
1387 | *tp = tty->termios; | |
1388 | } | |
1389 | ||
1390 | /** | |
1391 | * tty_flush_works - flush all works of a tty/pty pair | |
1392 | * @tty: tty device to flush works for (or either end of a pty pair) | |
1393 | * | |
1394 | * Sync flush all works belonging to @tty (and the 'other' tty). | |
1395 | */ | |
1396 | static void tty_flush_works(struct tty_struct *tty) | |
1397 | { | |
1398 | flush_work(&tty->SAK_work); | |
1399 | flush_work(&tty->hangup_work); | |
1400 | if (tty->link) { | |
1401 | flush_work(&tty->link->SAK_work); | |
1402 | flush_work(&tty->link->hangup_work); | |
1403 | } | |
1404 | } | |
1405 | ||
1406 | /** | |
1407 | * release_one_tty - release tty structure memory | |
1408 | * @kref: kref of tty we are obliterating | |
1409 | * | |
1410 | * Releases memory associated with a tty structure, and clears out the | |
1411 | * driver table slots. This function is called when a device is no longer | |
1412 | * in use. It also gets called when setup of a device fails. | |
1413 | * | |
1414 | * Locking: | |
1415 | * takes the file list lock internally when working on the list | |
1416 | * of ttys that the driver keeps. | |
1417 | * | |
1418 | * This method gets called from a work queue so that the driver private | |
1419 | * cleanup ops can sleep (needed for USB at least) | |
1420 | */ | |
1421 | static void release_one_tty(struct work_struct *work) | |
1422 | { | |
1423 | struct tty_struct *tty = | |
1424 | container_of(work, struct tty_struct, hangup_work); | |
1425 | struct tty_driver *driver = tty->driver; | |
1426 | struct module *owner = driver->owner; | |
1427 | ||
1428 | if (tty->ops->cleanup) | |
1429 | tty->ops->cleanup(tty); | |
1430 | ||
1431 | tty->magic = 0; | |
1432 | tty_driver_kref_put(driver); | |
1433 | module_put(owner); | |
1434 | ||
1435 | spin_lock(&tty->files_lock); | |
1436 | list_del_init(&tty->tty_files); | |
1437 | spin_unlock(&tty->files_lock); | |
1438 | ||
1439 | put_pid(tty->pgrp); | |
1440 | put_pid(tty->session); | |
1441 | free_tty_struct(tty); | |
1442 | } | |
1443 | ||
1444 | static void queue_release_one_tty(struct kref *kref) | |
1445 | { | |
1446 | struct tty_struct *tty = container_of(kref, struct tty_struct, kref); | |
1447 | ||
1448 | /* The hangup queue is now free so we can reuse it rather than | |
1449 | waste a chunk of memory for each port */ | |
1450 | INIT_WORK(&tty->hangup_work, release_one_tty); | |
1451 | schedule_work(&tty->hangup_work); | |
1452 | } | |
1453 | ||
1454 | /** | |
1455 | * tty_kref_put - release a tty kref | |
1456 | * @tty: tty device | |
1457 | * | |
1458 | * Release a reference to a tty device and if need be let the kref | |
1459 | * layer destruct the object for us | |
1460 | */ | |
1461 | ||
1462 | void tty_kref_put(struct tty_struct *tty) | |
1463 | { | |
1464 | if (tty) | |
1465 | kref_put(&tty->kref, queue_release_one_tty); | |
1466 | } | |
1467 | EXPORT_SYMBOL(tty_kref_put); | |
1468 | ||
1469 | /** | |
1470 | * release_tty - release tty structure memory | |
1471 | * | |
1472 | * Release both @tty and a possible linked partner (think pty pair), | |
1473 | * and decrement the refcount of the backing module. | |
1474 | * | |
1475 | * Locking: | |
1476 | * tty_mutex | |
1477 | * takes the file list lock internally when working on the list | |
1478 | * of ttys that the driver keeps. | |
1479 | * | |
1480 | */ | |
1481 | static void release_tty(struct tty_struct *tty, int idx) | |
1482 | { | |
1483 | /* This should always be true but check for the moment */ | |
1484 | WARN_ON(tty->index != idx); | |
1485 | WARN_ON(!mutex_is_locked(&tty_mutex)); | |
1486 | if (tty->ops->shutdown) | |
1487 | tty->ops->shutdown(tty); | |
1488 | tty_free_termios(tty); | |
1489 | tty_driver_remove_tty(tty->driver, tty); | |
1490 | tty->port->itty = NULL; | |
1491 | if (tty->link) | |
1492 | tty->link->port->itty = NULL; | |
1493 | tty_buffer_cancel_work(tty->port); | |
1494 | if (tty->link) | |
1495 | tty_buffer_cancel_work(tty->link->port); | |
1496 | ||
1497 | tty_kref_put(tty->link); | |
1498 | tty_kref_put(tty); | |
1499 | } | |
1500 | ||
1501 | /** | |
1502 | * tty_release_checks - check a tty before real release | |
1503 | * @tty: tty to check | |
1504 | * @o_tty: link of @tty (if any) | |
1505 | * @idx: index of the tty | |
1506 | * | |
1507 | * Performs some paranoid checking before true release of the @tty. | |
1508 | * This is a no-op unless TTY_PARANOIA_CHECK is defined. | |
1509 | */ | |
1510 | static int tty_release_checks(struct tty_struct *tty, int idx) | |
1511 | { | |
1512 | #ifdef TTY_PARANOIA_CHECK | |
1513 | if (idx < 0 || idx >= tty->driver->num) { | |
1514 | tty_debug(tty, "bad idx %d\n", idx); | |
1515 | return -1; | |
1516 | } | |
1517 | ||
1518 | /* not much to check for devpts */ | |
1519 | if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) | |
1520 | return 0; | |
1521 | ||
1522 | if (tty != tty->driver->ttys[idx]) { | |
1523 | tty_debug(tty, "bad driver table[%d] = %p\n", | |
1524 | idx, tty->driver->ttys[idx]); | |
1525 | return -1; | |
1526 | } | |
1527 | if (tty->driver->other) { | |
1528 | struct tty_struct *o_tty = tty->link; | |
1529 | ||
1530 | if (o_tty != tty->driver->other->ttys[idx]) { | |
1531 | tty_debug(tty, "bad other table[%d] = %p\n", | |
1532 | idx, tty->driver->other->ttys[idx]); | |
1533 | return -1; | |
1534 | } | |
1535 | if (o_tty->link != tty) { | |
1536 | tty_debug(tty, "bad link = %p\n", o_tty->link); | |
1537 | return -1; | |
1538 | } | |
1539 | } | |
1540 | #endif | |
1541 | return 0; | |
1542 | } | |
1543 | ||
1544 | /** | |
1545 | * tty_kclose - closes tty opened by tty_kopen | |
1546 | * @tty: tty device | |
1547 | * | |
1548 | * Performs the final steps to release and free a tty device. It is the | |
1549 | * same as tty_release_struct except that it also resets TTY_PORT_KOPENED | |
1550 | * flag on tty->port. | |
1551 | */ | |
1552 | void tty_kclose(struct tty_struct *tty) | |
1553 | { | |
1554 | /* | |
1555 | * Ask the line discipline code to release its structures | |
1556 | */ | |
1557 | tty_ldisc_release(tty); | |
1558 | ||
1559 | /* Wait for pending work before tty destruction commmences */ | |
1560 | tty_flush_works(tty); | |
1561 | ||
1562 | tty_debug_hangup(tty, "freeing structure\n"); | |
1563 | /* | |
1564 | * The release_tty function takes care of the details of clearing | |
1565 | * the slots and preserving the termios structure. The tty_unlock_pair | |
1566 | * should be safe as we keep a kref while the tty is locked (so the | |
1567 | * unlock never unlocks a freed tty). | |
1568 | */ | |
1569 | mutex_lock(&tty_mutex); | |
1570 | tty_port_set_kopened(tty->port, 0); | |
1571 | release_tty(tty, tty->index); | |
1572 | mutex_unlock(&tty_mutex); | |
1573 | } | |
1574 | EXPORT_SYMBOL_GPL(tty_kclose); | |
1575 | ||
1576 | /** | |
1577 | * tty_release_struct - release a tty struct | |
1578 | * @tty: tty device | |
1579 | * @idx: index of the tty | |
1580 | * | |
1581 | * Performs the final steps to release and free a tty device. It is | |
1582 | * roughly the reverse of tty_init_dev. | |
1583 | */ | |
1584 | void tty_release_struct(struct tty_struct *tty, int idx) | |
1585 | { | |
1586 | /* | |
1587 | * Ask the line discipline code to release its structures | |
1588 | */ | |
1589 | tty_ldisc_release(tty); | |
1590 | ||
1591 | /* Wait for pending work before tty destruction commmences */ | |
1592 | tty_flush_works(tty); | |
1593 | ||
1594 | tty_debug_hangup(tty, "freeing structure\n"); | |
1595 | /* | |
1596 | * The release_tty function takes care of the details of clearing | |
1597 | * the slots and preserving the termios structure. The tty_unlock_pair | |
1598 | * should be safe as we keep a kref while the tty is locked (so the | |
1599 | * unlock never unlocks a freed tty). | |
1600 | */ | |
1601 | mutex_lock(&tty_mutex); | |
1602 | release_tty(tty, idx); | |
1603 | mutex_unlock(&tty_mutex); | |
1604 | } | |
1605 | EXPORT_SYMBOL_GPL(tty_release_struct); | |
1606 | ||
1607 | /** | |
1608 | * tty_release - vfs callback for close | |
1609 | * @inode: inode of tty | |
1610 | * @filp: file pointer for handle to tty | |
1611 | * | |
1612 | * Called the last time each file handle is closed that references | |
1613 | * this tty. There may however be several such references. | |
1614 | * | |
1615 | * Locking: | |
1616 | * Takes bkl. See tty_release_dev | |
1617 | * | |
1618 | * Even releasing the tty structures is a tricky business.. We have | |
1619 | * to be very careful that the structures are all released at the | |
1620 | * same time, as interrupts might otherwise get the wrong pointers. | |
1621 | * | |
1622 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
1623 | * lead to double frees or releasing memory still in use. | |
1624 | */ | |
1625 | ||
1626 | int tty_release(struct inode *inode, struct file *filp) | |
1627 | { | |
1628 | struct tty_struct *tty = file_tty(filp); | |
1629 | struct tty_struct *o_tty = NULL; | |
1630 | int do_sleep, final; | |
1631 | int idx; | |
1632 | long timeout = 0; | |
1633 | int once = 1; | |
1634 | ||
1635 | if (tty_paranoia_check(tty, inode, __func__)) | |
1636 | return 0; | |
1637 | ||
1638 | tty_lock(tty); | |
1639 | check_tty_count(tty, __func__); | |
1640 | ||
1641 | __tty_fasync(-1, filp, 0); | |
1642 | ||
1643 | idx = tty->index; | |
1644 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
1645 | tty->driver->subtype == PTY_TYPE_MASTER) | |
1646 | o_tty = tty->link; | |
1647 | ||
1648 | if (tty_release_checks(tty, idx)) { | |
1649 | tty_unlock(tty); | |
1650 | return 0; | |
1651 | } | |
1652 | ||
1653 | tty_debug_hangup(tty, "releasing (count=%d)\n", tty->count); | |
1654 | ||
1655 | if (tty->ops->close) | |
1656 | tty->ops->close(tty, filp); | |
1657 | ||
1658 | /* If tty is pty master, lock the slave pty (stable lock order) */ | |
1659 | tty_lock_slave(o_tty); | |
1660 | ||
1661 | /* | |
1662 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
1663 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
1664 | * wait queues and kick everyone out _before_ actually starting to | |
1665 | * close. This ensures that we won't block while releasing the tty | |
1666 | * structure. | |
1667 | * | |
1668 | * The test for the o_tty closing is necessary, since the master and | |
1669 | * slave sides may close in any order. If the slave side closes out | |
1670 | * first, its count will be one, since the master side holds an open. | |
1671 | * Thus this test wouldn't be triggered at the time the slave closed, | |
1672 | * so we do it now. | |
1673 | */ | |
1674 | while (1) { | |
1675 | do_sleep = 0; | |
1676 | ||
1677 | if (tty->count <= 1) { | |
1678 | if (waitqueue_active(&tty->read_wait)) { | |
1679 | wake_up_poll(&tty->read_wait, EPOLLIN); | |
1680 | do_sleep++; | |
1681 | } | |
1682 | if (waitqueue_active(&tty->write_wait)) { | |
1683 | wake_up_poll(&tty->write_wait, EPOLLOUT); | |
1684 | do_sleep++; | |
1685 | } | |
1686 | } | |
1687 | if (o_tty && o_tty->count <= 1) { | |
1688 | if (waitqueue_active(&o_tty->read_wait)) { | |
1689 | wake_up_poll(&o_tty->read_wait, EPOLLIN); | |
1690 | do_sleep++; | |
1691 | } | |
1692 | if (waitqueue_active(&o_tty->write_wait)) { | |
1693 | wake_up_poll(&o_tty->write_wait, EPOLLOUT); | |
1694 | do_sleep++; | |
1695 | } | |
1696 | } | |
1697 | if (!do_sleep) | |
1698 | break; | |
1699 | ||
1700 | if (once) { | |
1701 | once = 0; | |
1702 | tty_warn(tty, "read/write wait queue active!\n"); | |
1703 | } | |
1704 | schedule_timeout_killable(timeout); | |
1705 | if (timeout < 120 * HZ) | |
1706 | timeout = 2 * timeout + 1; | |
1707 | else | |
1708 | timeout = MAX_SCHEDULE_TIMEOUT; | |
1709 | } | |
1710 | ||
1711 | if (o_tty) { | |
1712 | if (--o_tty->count < 0) { | |
1713 | tty_warn(tty, "bad slave count (%d)\n", o_tty->count); | |
1714 | o_tty->count = 0; | |
1715 | } | |
1716 | } | |
1717 | if (--tty->count < 0) { | |
1718 | tty_warn(tty, "bad tty->count (%d)\n", tty->count); | |
1719 | tty->count = 0; | |
1720 | } | |
1721 | ||
1722 | /* | |
1723 | * We've decremented tty->count, so we need to remove this file | |
1724 | * descriptor off the tty->tty_files list; this serves two | |
1725 | * purposes: | |
1726 | * - check_tty_count sees the correct number of file descriptors | |
1727 | * associated with this tty. | |
1728 | * - do_tty_hangup no longer sees this file descriptor as | |
1729 | * something that needs to be handled for hangups. | |
1730 | */ | |
1731 | tty_del_file(filp); | |
1732 | ||
1733 | /* | |
1734 | * Perform some housekeeping before deciding whether to return. | |
1735 | * | |
1736 | * If _either_ side is closing, make sure there aren't any | |
1737 | * processes that still think tty or o_tty is their controlling | |
1738 | * tty. | |
1739 | */ | |
1740 | if (!tty->count) { | |
1741 | read_lock(&tasklist_lock); | |
1742 | session_clear_tty(tty->session); | |
1743 | if (o_tty) | |
1744 | session_clear_tty(o_tty->session); | |
1745 | read_unlock(&tasklist_lock); | |
1746 | } | |
1747 | ||
1748 | /* check whether both sides are closing ... */ | |
1749 | final = !tty->count && !(o_tty && o_tty->count); | |
1750 | ||
1751 | tty_unlock_slave(o_tty); | |
1752 | tty_unlock(tty); | |
1753 | ||
1754 | /* At this point, the tty->count == 0 should ensure a dead tty | |
1755 | cannot be re-opened by a racing opener */ | |
1756 | ||
1757 | if (!final) | |
1758 | return 0; | |
1759 | ||
1760 | tty_debug_hangup(tty, "final close\n"); | |
1761 | ||
1762 | tty_release_struct(tty, idx); | |
1763 | return 0; | |
1764 | } | |
1765 | ||
1766 | /** | |
1767 | * tty_open_current_tty - get locked tty of current task | |
1768 | * @device: device number | |
1769 | * @filp: file pointer to tty | |
1770 | * @return: locked tty of the current task iff @device is /dev/tty | |
1771 | * | |
1772 | * Performs a re-open of the current task's controlling tty. | |
1773 | * | |
1774 | * We cannot return driver and index like for the other nodes because | |
1775 | * devpts will not work then. It expects inodes to be from devpts FS. | |
1776 | */ | |
1777 | static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp) | |
1778 | { | |
1779 | struct tty_struct *tty; | |
1780 | int retval; | |
1781 | ||
1782 | if (device != MKDEV(TTYAUX_MAJOR, 0)) | |
1783 | return NULL; | |
1784 | ||
1785 | tty = get_current_tty(); | |
1786 | if (!tty) | |
1787 | return ERR_PTR(-ENXIO); | |
1788 | ||
1789 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ | |
1790 | /* noctty = 1; */ | |
1791 | tty_lock(tty); | |
1792 | tty_kref_put(tty); /* safe to drop the kref now */ | |
1793 | ||
1794 | retval = tty_reopen(tty); | |
1795 | if (retval < 0) { | |
1796 | tty_unlock(tty); | |
1797 | tty = ERR_PTR(retval); | |
1798 | } | |
1799 | return tty; | |
1800 | } | |
1801 | ||
1802 | /** | |
1803 | * tty_lookup_driver - lookup a tty driver for a given device file | |
1804 | * @device: device number | |
1805 | * @filp: file pointer to tty | |
1806 | * @index: index for the device in the @return driver | |
1807 | * @return: driver for this inode (with increased refcount) | |
1808 | * | |
1809 | * If @return is not erroneous, the caller is responsible to decrement the | |
1810 | * refcount by tty_driver_kref_put. | |
1811 | * | |
1812 | * Locking: tty_mutex protects get_tty_driver | |
1813 | */ | |
1814 | static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, | |
1815 | int *index) | |
1816 | { | |
1817 | struct tty_driver *driver; | |
1818 | ||
1819 | switch (device) { | |
1820 | #ifdef CONFIG_VT | |
1821 | case MKDEV(TTY_MAJOR, 0): { | |
1822 | extern struct tty_driver *console_driver; | |
1823 | driver = tty_driver_kref_get(console_driver); | |
1824 | *index = fg_console; | |
1825 | break; | |
1826 | } | |
1827 | #endif | |
1828 | case MKDEV(TTYAUX_MAJOR, 1): { | |
1829 | struct tty_driver *console_driver = console_device(index); | |
1830 | if (console_driver) { | |
1831 | driver = tty_driver_kref_get(console_driver); | |
1832 | if (driver && filp) { | |
1833 | /* Don't let /dev/console block */ | |
1834 | filp->f_flags |= O_NONBLOCK; | |
1835 | break; | |
1836 | } | |
1837 | } | |
1838 | return ERR_PTR(-ENODEV); | |
1839 | } | |
1840 | default: | |
1841 | driver = get_tty_driver(device, index); | |
1842 | if (!driver) | |
1843 | return ERR_PTR(-ENODEV); | |
1844 | break; | |
1845 | } | |
1846 | return driver; | |
1847 | } | |
1848 | ||
1849 | /** | |
1850 | * tty_kopen - open a tty device for kernel | |
1851 | * @device: dev_t of device to open | |
1852 | * | |
1853 | * Opens tty exclusively for kernel. Performs the driver lookup, | |
1854 | * makes sure it's not already opened and performs the first-time | |
1855 | * tty initialization. | |
1856 | * | |
1857 | * Returns the locked initialized &tty_struct | |
1858 | * | |
1859 | * Claims the global tty_mutex to serialize: | |
1860 | * - concurrent first-time tty initialization | |
1861 | * - concurrent tty driver removal w/ lookup | |
1862 | * - concurrent tty removal from driver table | |
1863 | */ | |
1864 | struct tty_struct *tty_kopen(dev_t device) | |
1865 | { | |
1866 | struct tty_struct *tty; | |
1867 | struct tty_driver *driver = NULL; | |
1868 | int index = -1; | |
1869 | ||
1870 | mutex_lock(&tty_mutex); | |
1871 | driver = tty_lookup_driver(device, NULL, &index); | |
1872 | if (IS_ERR(driver)) { | |
1873 | mutex_unlock(&tty_mutex); | |
1874 | return ERR_CAST(driver); | |
1875 | } | |
1876 | ||
1877 | /* check whether we're reopening an existing tty */ | |
1878 | tty = tty_driver_lookup_tty(driver, NULL, index); | |
1879 | if (IS_ERR(tty)) | |
1880 | goto out; | |
1881 | ||
1882 | if (tty) { | |
1883 | /* drop kref from tty_driver_lookup_tty() */ | |
1884 | tty_kref_put(tty); | |
1885 | tty = ERR_PTR(-EBUSY); | |
1886 | } else { /* tty_init_dev returns tty with the tty_lock held */ | |
1887 | tty = tty_init_dev(driver, index); | |
1888 | if (IS_ERR(tty)) | |
1889 | goto out; | |
1890 | tty_port_set_kopened(tty->port, 1); | |
1891 | } | |
1892 | out: | |
1893 | mutex_unlock(&tty_mutex); | |
1894 | tty_driver_kref_put(driver); | |
1895 | return tty; | |
1896 | } | |
1897 | EXPORT_SYMBOL_GPL(tty_kopen); | |
1898 | ||
1899 | /** | |
1900 | * tty_open_by_driver - open a tty device | |
1901 | * @device: dev_t of device to open | |
1902 | * @inode: inode of device file | |
1903 | * @filp: file pointer to tty | |
1904 | * | |
1905 | * Performs the driver lookup, checks for a reopen, or otherwise | |
1906 | * performs the first-time tty initialization. | |
1907 | * | |
1908 | * Returns the locked initialized or re-opened &tty_struct | |
1909 | * | |
1910 | * Claims the global tty_mutex to serialize: | |
1911 | * - concurrent first-time tty initialization | |
1912 | * - concurrent tty driver removal w/ lookup | |
1913 | * - concurrent tty removal from driver table | |
1914 | */ | |
1915 | static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode, | |
1916 | struct file *filp) | |
1917 | { | |
1918 | struct tty_struct *tty; | |
1919 | struct tty_driver *driver = NULL; | |
1920 | int index = -1; | |
1921 | int retval; | |
1922 | ||
1923 | mutex_lock(&tty_mutex); | |
1924 | driver = tty_lookup_driver(device, filp, &index); | |
1925 | if (IS_ERR(driver)) { | |
1926 | mutex_unlock(&tty_mutex); | |
1927 | return ERR_CAST(driver); | |
1928 | } | |
1929 | ||
1930 | /* check whether we're reopening an existing tty */ | |
1931 | tty = tty_driver_lookup_tty(driver, filp, index); | |
1932 | if (IS_ERR(tty)) { | |
1933 | mutex_unlock(&tty_mutex); | |
1934 | goto out; | |
1935 | } | |
1936 | ||
1937 | if (tty) { | |
1938 | if (tty_port_kopened(tty->port)) { | |
1939 | tty_kref_put(tty); | |
1940 | mutex_unlock(&tty_mutex); | |
1941 | tty = ERR_PTR(-EBUSY); | |
1942 | goto out; | |
1943 | } | |
1944 | mutex_unlock(&tty_mutex); | |
1945 | retval = tty_lock_interruptible(tty); | |
1946 | tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */ | |
1947 | if (retval) { | |
1948 | if (retval == -EINTR) | |
1949 | retval = -ERESTARTSYS; | |
1950 | tty = ERR_PTR(retval); | |
1951 | goto out; | |
1952 | } | |
1953 | retval = tty_reopen(tty); | |
1954 | if (retval < 0) { | |
1955 | tty_unlock(tty); | |
1956 | tty = ERR_PTR(retval); | |
1957 | } | |
1958 | } else { /* Returns with the tty_lock held for now */ | |
1959 | tty = tty_init_dev(driver, index); | |
1960 | mutex_unlock(&tty_mutex); | |
1961 | } | |
1962 | out: | |
1963 | tty_driver_kref_put(driver); | |
1964 | return tty; | |
1965 | } | |
1966 | ||
1967 | /** | |
1968 | * tty_open - open a tty device | |
1969 | * @inode: inode of device file | |
1970 | * @filp: file pointer to tty | |
1971 | * | |
1972 | * tty_open and tty_release keep up the tty count that contains the | |
1973 | * number of opens done on a tty. We cannot use the inode-count, as | |
1974 | * different inodes might point to the same tty. | |
1975 | * | |
1976 | * Open-counting is needed for pty masters, as well as for keeping | |
1977 | * track of serial lines: DTR is dropped when the last close happens. | |
1978 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
1979 | * | |
1980 | * The termios state of a pty is reset on first open so that | |
1981 | * settings don't persist across reuse. | |
1982 | * | |
1983 | * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev. | |
1984 | * tty->count should protect the rest. | |
1985 | * ->siglock protects ->signal/->sighand | |
1986 | * | |
1987 | * Note: the tty_unlock/lock cases without a ref are only safe due to | |
1988 | * tty_mutex | |
1989 | */ | |
1990 | ||
1991 | static int tty_open(struct inode *inode, struct file *filp) | |
1992 | { | |
1993 | struct tty_struct *tty; | |
1994 | int noctty, retval; | |
1995 | dev_t device = inode->i_rdev; | |
1996 | unsigned saved_flags = filp->f_flags; | |
1997 | ||
1998 | nonseekable_open(inode, filp); | |
1999 | ||
2000 | retry_open: | |
2001 | retval = tty_alloc_file(filp); | |
2002 | if (retval) | |
2003 | return -ENOMEM; | |
2004 | ||
2005 | tty = tty_open_current_tty(device, filp); | |
2006 | if (!tty) | |
2007 | tty = tty_open_by_driver(device, inode, filp); | |
2008 | ||
2009 | if (IS_ERR(tty)) { | |
2010 | tty_free_file(filp); | |
2011 | retval = PTR_ERR(tty); | |
2012 | if (retval != -EAGAIN || signal_pending(current)) | |
2013 | return retval; | |
2014 | schedule(); | |
2015 | goto retry_open; | |
2016 | } | |
2017 | ||
2018 | tty_add_file(tty, filp); | |
2019 | ||
2020 | check_tty_count(tty, __func__); | |
2021 | tty_debug_hangup(tty, "opening (count=%d)\n", tty->count); | |
2022 | ||
2023 | if (tty->ops->open) | |
2024 | retval = tty->ops->open(tty, filp); | |
2025 | else | |
2026 | retval = -ENODEV; | |
2027 | filp->f_flags = saved_flags; | |
2028 | ||
2029 | if (retval) { | |
2030 | tty_debug_hangup(tty, "open error %d, releasing\n", retval); | |
2031 | ||
2032 | tty_unlock(tty); /* need to call tty_release without BTM */ | |
2033 | tty_release(inode, filp); | |
2034 | if (retval != -ERESTARTSYS) | |
2035 | return retval; | |
2036 | ||
2037 | if (signal_pending(current)) | |
2038 | return retval; | |
2039 | ||
2040 | schedule(); | |
2041 | /* | |
2042 | * Need to reset f_op in case a hangup happened. | |
2043 | */ | |
2044 | if (tty_hung_up_p(filp)) | |
2045 | filp->f_op = &tty_fops; | |
2046 | goto retry_open; | |
2047 | } | |
2048 | clear_bit(TTY_HUPPED, &tty->flags); | |
2049 | ||
2050 | noctty = (filp->f_flags & O_NOCTTY) || | |
2051 | (IS_ENABLED(CONFIG_VT) && device == MKDEV(TTY_MAJOR, 0)) || | |
2052 | device == MKDEV(TTYAUX_MAJOR, 1) || | |
2053 | (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2054 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2055 | if (!noctty) | |
2056 | tty_open_proc_set_tty(filp, tty); | |
2057 | tty_unlock(tty); | |
2058 | return 0; | |
2059 | } | |
2060 | ||
2061 | ||
2062 | ||
2063 | /** | |
2064 | * tty_poll - check tty status | |
2065 | * @filp: file being polled | |
2066 | * @wait: poll wait structures to update | |
2067 | * | |
2068 | * Call the line discipline polling method to obtain the poll | |
2069 | * status of the device. | |
2070 | * | |
2071 | * Locking: locks called line discipline but ldisc poll method | |
2072 | * may be re-entered freely by other callers. | |
2073 | */ | |
2074 | ||
2075 | static __poll_t tty_poll(struct file *filp, poll_table *wait) | |
2076 | { | |
2077 | struct tty_struct *tty = file_tty(filp); | |
2078 | struct tty_ldisc *ld; | |
2079 | __poll_t ret = 0; | |
2080 | ||
2081 | if (tty_paranoia_check(tty, file_inode(filp), "tty_poll")) | |
2082 | return 0; | |
2083 | ||
2084 | ld = tty_ldisc_ref_wait(tty); | |
2085 | if (!ld) | |
2086 | return hung_up_tty_poll(filp, wait); | |
2087 | if (ld->ops->poll) | |
2088 | ret = ld->ops->poll(tty, filp, wait); | |
2089 | tty_ldisc_deref(ld); | |
2090 | return ret; | |
2091 | } | |
2092 | ||
2093 | static int __tty_fasync(int fd, struct file *filp, int on) | |
2094 | { | |
2095 | struct tty_struct *tty = file_tty(filp); | |
2096 | unsigned long flags; | |
2097 | int retval = 0; | |
2098 | ||
2099 | if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync")) | |
2100 | goto out; | |
2101 | ||
2102 | retval = fasync_helper(fd, filp, on, &tty->fasync); | |
2103 | if (retval <= 0) | |
2104 | goto out; | |
2105 | ||
2106 | if (on) { | |
2107 | enum pid_type type; | |
2108 | struct pid *pid; | |
2109 | ||
2110 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
2111 | if (tty->pgrp) { | |
2112 | pid = tty->pgrp; | |
2113 | type = PIDTYPE_PGID; | |
2114 | } else { | |
2115 | pid = task_pid(current); | |
2116 | type = PIDTYPE_PID; | |
2117 | } | |
2118 | get_pid(pid); | |
2119 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
2120 | __f_setown(filp, pid, type, 0); | |
2121 | put_pid(pid); | |
2122 | retval = 0; | |
2123 | } | |
2124 | out: | |
2125 | return retval; | |
2126 | } | |
2127 | ||
2128 | static int tty_fasync(int fd, struct file *filp, int on) | |
2129 | { | |
2130 | struct tty_struct *tty = file_tty(filp); | |
2131 | int retval = -ENOTTY; | |
2132 | ||
2133 | tty_lock(tty); | |
2134 | if (!tty_hung_up_p(filp)) | |
2135 | retval = __tty_fasync(fd, filp, on); | |
2136 | tty_unlock(tty); | |
2137 | ||
2138 | return retval; | |
2139 | } | |
2140 | ||
2141 | /** | |
2142 | * tiocsti - fake input character | |
2143 | * @tty: tty to fake input into | |
2144 | * @p: pointer to character | |
2145 | * | |
2146 | * Fake input to a tty device. Does the necessary locking and | |
2147 | * input management. | |
2148 | * | |
2149 | * FIXME: does not honour flow control ?? | |
2150 | * | |
2151 | * Locking: | |
2152 | * Called functions take tty_ldiscs_lock | |
2153 | * current->signal->tty check is safe without locks | |
2154 | * | |
2155 | * FIXME: may race normal receive processing | |
2156 | */ | |
2157 | ||
2158 | static int tiocsti(struct tty_struct *tty, char __user *p) | |
2159 | { | |
2160 | char ch, mbz = 0; | |
2161 | struct tty_ldisc *ld; | |
2162 | ||
2163 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) | |
2164 | return -EPERM; | |
2165 | if (get_user(ch, p)) | |
2166 | return -EFAULT; | |
2167 | tty_audit_tiocsti(tty, ch); | |
2168 | ld = tty_ldisc_ref_wait(tty); | |
2169 | if (!ld) | |
2170 | return -EIO; | |
2171 | ld->ops->receive_buf(tty, &ch, &mbz, 1); | |
2172 | tty_ldisc_deref(ld); | |
2173 | return 0; | |
2174 | } | |
2175 | ||
2176 | /** | |
2177 | * tiocgwinsz - implement window query ioctl | |
2178 | * @tty; tty | |
2179 | * @arg: user buffer for result | |
2180 | * | |
2181 | * Copies the kernel idea of the window size into the user buffer. | |
2182 | * | |
2183 | * Locking: tty->winsize_mutex is taken to ensure the winsize data | |
2184 | * is consistent. | |
2185 | */ | |
2186 | ||
2187 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) | |
2188 | { | |
2189 | int err; | |
2190 | ||
2191 | mutex_lock(&tty->winsize_mutex); | |
2192 | err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); | |
2193 | mutex_unlock(&tty->winsize_mutex); | |
2194 | ||
2195 | return err ? -EFAULT: 0; | |
2196 | } | |
2197 | ||
2198 | /** | |
2199 | * tty_do_resize - resize event | |
2200 | * @tty: tty being resized | |
2201 | * @rows: rows (character) | |
2202 | * @cols: cols (character) | |
2203 | * | |
2204 | * Update the termios variables and send the necessary signals to | |
2205 | * peform a terminal resize correctly | |
2206 | */ | |
2207 | ||
2208 | int tty_do_resize(struct tty_struct *tty, struct winsize *ws) | |
2209 | { | |
2210 | struct pid *pgrp; | |
2211 | ||
2212 | /* Lock the tty */ | |
2213 | mutex_lock(&tty->winsize_mutex); | |
2214 | if (!memcmp(ws, &tty->winsize, sizeof(*ws))) | |
2215 | goto done; | |
2216 | ||
2217 | /* Signal the foreground process group */ | |
2218 | pgrp = tty_get_pgrp(tty); | |
2219 | if (pgrp) | |
2220 | kill_pgrp(pgrp, SIGWINCH, 1); | |
2221 | put_pid(pgrp); | |
2222 | ||
2223 | tty->winsize = *ws; | |
2224 | done: | |
2225 | mutex_unlock(&tty->winsize_mutex); | |
2226 | return 0; | |
2227 | } | |
2228 | EXPORT_SYMBOL(tty_do_resize); | |
2229 | ||
2230 | /** | |
2231 | * tiocswinsz - implement window size set ioctl | |
2232 | * @tty; tty side of tty | |
2233 | * @arg: user buffer for result | |
2234 | * | |
2235 | * Copies the user idea of the window size to the kernel. Traditionally | |
2236 | * this is just advisory information but for the Linux console it | |
2237 | * actually has driver level meaning and triggers a VC resize. | |
2238 | * | |
2239 | * Locking: | |
2240 | * Driver dependent. The default do_resize method takes the | |
2241 | * tty termios mutex and ctrl_lock. The console takes its own lock | |
2242 | * then calls into the default method. | |
2243 | */ | |
2244 | ||
2245 | static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg) | |
2246 | { | |
2247 | struct winsize tmp_ws; | |
2248 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
2249 | return -EFAULT; | |
2250 | ||
2251 | if (tty->ops->resize) | |
2252 | return tty->ops->resize(tty, &tmp_ws); | |
2253 | else | |
2254 | return tty_do_resize(tty, &tmp_ws); | |
2255 | } | |
2256 | ||
2257 | /** | |
2258 | * tioccons - allow admin to move logical console | |
2259 | * @file: the file to become console | |
2260 | * | |
2261 | * Allow the administrator to move the redirected console device | |
2262 | * | |
2263 | * Locking: uses redirect_lock to guard the redirect information | |
2264 | */ | |
2265 | ||
2266 | static int tioccons(struct file *file) | |
2267 | { | |
2268 | if (!capable(CAP_SYS_ADMIN)) | |
2269 | return -EPERM; | |
2270 | if (file->f_op->write == redirected_tty_write) { | |
2271 | struct file *f; | |
2272 | spin_lock(&redirect_lock); | |
2273 | f = redirect; | |
2274 | redirect = NULL; | |
2275 | spin_unlock(&redirect_lock); | |
2276 | if (f) | |
2277 | fput(f); | |
2278 | return 0; | |
2279 | } | |
2280 | spin_lock(&redirect_lock); | |
2281 | if (redirect) { | |
2282 | spin_unlock(&redirect_lock); | |
2283 | return -EBUSY; | |
2284 | } | |
2285 | redirect = get_file(file); | |
2286 | spin_unlock(&redirect_lock); | |
2287 | return 0; | |
2288 | } | |
2289 | ||
2290 | /** | |
2291 | * fionbio - non blocking ioctl | |
2292 | * @file: file to set blocking value | |
2293 | * @p: user parameter | |
2294 | * | |
2295 | * Historical tty interfaces had a blocking control ioctl before | |
2296 | * the generic functionality existed. This piece of history is preserved | |
2297 | * in the expected tty API of posix OS's. | |
2298 | * | |
2299 | * Locking: none, the open file handle ensures it won't go away. | |
2300 | */ | |
2301 | ||
2302 | static int fionbio(struct file *file, int __user *p) | |
2303 | { | |
2304 | int nonblock; | |
2305 | ||
2306 | if (get_user(nonblock, p)) | |
2307 | return -EFAULT; | |
2308 | ||
2309 | spin_lock(&file->f_lock); | |
2310 | if (nonblock) | |
2311 | file->f_flags |= O_NONBLOCK; | |
2312 | else | |
2313 | file->f_flags &= ~O_NONBLOCK; | |
2314 | spin_unlock(&file->f_lock); | |
2315 | return 0; | |
2316 | } | |
2317 | ||
2318 | /** | |
2319 | * tiocsetd - set line discipline | |
2320 | * @tty: tty device | |
2321 | * @p: pointer to user data | |
2322 | * | |
2323 | * Set the line discipline according to user request. | |
2324 | * | |
2325 | * Locking: see tty_set_ldisc, this function is just a helper | |
2326 | */ | |
2327 | ||
2328 | static int tiocsetd(struct tty_struct *tty, int __user *p) | |
2329 | { | |
2330 | int disc; | |
2331 | int ret; | |
2332 | ||
2333 | if (get_user(disc, p)) | |
2334 | return -EFAULT; | |
2335 | ||
2336 | ret = tty_set_ldisc(tty, disc); | |
2337 | ||
2338 | return ret; | |
2339 | } | |
2340 | ||
2341 | /** | |
2342 | * tiocgetd - get line discipline | |
2343 | * @tty: tty device | |
2344 | * @p: pointer to user data | |
2345 | * | |
2346 | * Retrieves the line discipline id directly from the ldisc. | |
2347 | * | |
2348 | * Locking: waits for ldisc reference (in case the line discipline | |
2349 | * is changing or the tty is being hungup) | |
2350 | */ | |
2351 | ||
2352 | static int tiocgetd(struct tty_struct *tty, int __user *p) | |
2353 | { | |
2354 | struct tty_ldisc *ld; | |
2355 | int ret; | |
2356 | ||
2357 | ld = tty_ldisc_ref_wait(tty); | |
2358 | if (!ld) | |
2359 | return -EIO; | |
2360 | ret = put_user(ld->ops->num, p); | |
2361 | tty_ldisc_deref(ld); | |
2362 | return ret; | |
2363 | } | |
2364 | ||
2365 | /** | |
2366 | * send_break - performed time break | |
2367 | * @tty: device to break on | |
2368 | * @duration: timeout in mS | |
2369 | * | |
2370 | * Perform a timed break on hardware that lacks its own driver level | |
2371 | * timed break functionality. | |
2372 | * | |
2373 | * Locking: | |
2374 | * atomic_write_lock serializes | |
2375 | * | |
2376 | */ | |
2377 | ||
2378 | static int send_break(struct tty_struct *tty, unsigned int duration) | |
2379 | { | |
2380 | int retval; | |
2381 | ||
2382 | if (tty->ops->break_ctl == NULL) | |
2383 | return 0; | |
2384 | ||
2385 | if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK) | |
2386 | retval = tty->ops->break_ctl(tty, duration); | |
2387 | else { | |
2388 | /* Do the work ourselves */ | |
2389 | if (tty_write_lock(tty, 0) < 0) | |
2390 | return -EINTR; | |
2391 | retval = tty->ops->break_ctl(tty, -1); | |
2392 | if (retval) | |
2393 | goto out; | |
2394 | if (!signal_pending(current)) | |
2395 | msleep_interruptible(duration); | |
2396 | retval = tty->ops->break_ctl(tty, 0); | |
2397 | out: | |
2398 | tty_write_unlock(tty); | |
2399 | if (signal_pending(current)) | |
2400 | retval = -EINTR; | |
2401 | } | |
2402 | return retval; | |
2403 | } | |
2404 | ||
2405 | /** | |
2406 | * tty_tiocmget - get modem status | |
2407 | * @tty: tty device | |
2408 | * @file: user file pointer | |
2409 | * @p: pointer to result | |
2410 | * | |
2411 | * Obtain the modem status bits from the tty driver if the feature | |
2412 | * is supported. Return -EINVAL if it is not available. | |
2413 | * | |
2414 | * Locking: none (up to the driver) | |
2415 | */ | |
2416 | ||
2417 | static int tty_tiocmget(struct tty_struct *tty, int __user *p) | |
2418 | { | |
2419 | int retval = -EINVAL; | |
2420 | ||
2421 | if (tty->ops->tiocmget) { | |
2422 | retval = tty->ops->tiocmget(tty); | |
2423 | ||
2424 | if (retval >= 0) | |
2425 | retval = put_user(retval, p); | |
2426 | } | |
2427 | return retval; | |
2428 | } | |
2429 | ||
2430 | /** | |
2431 | * tty_tiocmset - set modem status | |
2432 | * @tty: tty device | |
2433 | * @cmd: command - clear bits, set bits or set all | |
2434 | * @p: pointer to desired bits | |
2435 | * | |
2436 | * Set the modem status bits from the tty driver if the feature | |
2437 | * is supported. Return -EINVAL if it is not available. | |
2438 | * | |
2439 | * Locking: none (up to the driver) | |
2440 | */ | |
2441 | ||
2442 | static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd, | |
2443 | unsigned __user *p) | |
2444 | { | |
2445 | int retval; | |
2446 | unsigned int set, clear, val; | |
2447 | ||
2448 | if (tty->ops->tiocmset == NULL) | |
2449 | return -EINVAL; | |
2450 | ||
2451 | retval = get_user(val, p); | |
2452 | if (retval) | |
2453 | return retval; | |
2454 | set = clear = 0; | |
2455 | switch (cmd) { | |
2456 | case TIOCMBIS: | |
2457 | set = val; | |
2458 | break; | |
2459 | case TIOCMBIC: | |
2460 | clear = val; | |
2461 | break; | |
2462 | case TIOCMSET: | |
2463 | set = val; | |
2464 | clear = ~val; | |
2465 | break; | |
2466 | } | |
2467 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
2468 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
2469 | return tty->ops->tiocmset(tty, set, clear); | |
2470 | } | |
2471 | ||
2472 | static int tty_tiocgicount(struct tty_struct *tty, void __user *arg) | |
2473 | { | |
2474 | int retval = -EINVAL; | |
2475 | struct serial_icounter_struct icount; | |
2476 | memset(&icount, 0, sizeof(icount)); | |
2477 | if (tty->ops->get_icount) | |
2478 | retval = tty->ops->get_icount(tty, &icount); | |
2479 | if (retval != 0) | |
2480 | return retval; | |
2481 | if (copy_to_user(arg, &icount, sizeof(icount))) | |
2482 | return -EFAULT; | |
2483 | return 0; | |
2484 | } | |
2485 | ||
2486 | static void tty_warn_deprecated_flags(struct serial_struct __user *ss) | |
2487 | { | |
2488 | static DEFINE_RATELIMIT_STATE(depr_flags, | |
2489 | DEFAULT_RATELIMIT_INTERVAL, | |
2490 | DEFAULT_RATELIMIT_BURST); | |
2491 | char comm[TASK_COMM_LEN]; | |
2492 | int flags; | |
2493 | ||
2494 | if (get_user(flags, &ss->flags)) | |
2495 | return; | |
2496 | ||
2497 | flags &= ASYNC_DEPRECATED; | |
2498 | ||
2499 | if (flags && __ratelimit(&depr_flags)) | |
2500 | pr_warn("%s: '%s' is using deprecated serial flags (with no effect): %.8x\n", | |
2501 | __func__, get_task_comm(comm, current), flags); | |
2502 | } | |
2503 | ||
2504 | /* | |
2505 | * if pty, return the slave side (real_tty) | |
2506 | * otherwise, return self | |
2507 | */ | |
2508 | static struct tty_struct *tty_pair_get_tty(struct tty_struct *tty) | |
2509 | { | |
2510 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2511 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2512 | tty = tty->link; | |
2513 | return tty; | |
2514 | } | |
2515 | ||
2516 | /* | |
2517 | * Split this up, as gcc can choke on it otherwise.. | |
2518 | */ | |
2519 | long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
2520 | { | |
2521 | struct tty_struct *tty = file_tty(file); | |
2522 | struct tty_struct *real_tty; | |
2523 | void __user *p = (void __user *)arg; | |
2524 | int retval; | |
2525 | struct tty_ldisc *ld; | |
2526 | ||
2527 | if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl")) | |
2528 | return -EINVAL; | |
2529 | ||
2530 | real_tty = tty_pair_get_tty(tty); | |
2531 | ||
2532 | /* | |
2533 | * Factor out some common prep work | |
2534 | */ | |
2535 | switch (cmd) { | |
2536 | case TIOCSETD: | |
2537 | case TIOCSBRK: | |
2538 | case TIOCCBRK: | |
2539 | case TCSBRK: | |
2540 | case TCSBRKP: | |
2541 | retval = tty_check_change(tty); | |
2542 | if (retval) | |
2543 | return retval; | |
2544 | if (cmd != TIOCCBRK) { | |
2545 | tty_wait_until_sent(tty, 0); | |
2546 | if (signal_pending(current)) | |
2547 | return -EINTR; | |
2548 | } | |
2549 | break; | |
2550 | } | |
2551 | ||
2552 | /* | |
2553 | * Now do the stuff. | |
2554 | */ | |
2555 | switch (cmd) { | |
2556 | case TIOCSTI: | |
2557 | return tiocsti(tty, p); | |
2558 | case TIOCGWINSZ: | |
2559 | return tiocgwinsz(real_tty, p); | |
2560 | case TIOCSWINSZ: | |
2561 | return tiocswinsz(real_tty, p); | |
2562 | case TIOCCONS: | |
2563 | return real_tty != tty ? -EINVAL : tioccons(file); | |
2564 | case FIONBIO: | |
2565 | return fionbio(file, p); | |
2566 | case TIOCEXCL: | |
2567 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
2568 | return 0; | |
2569 | case TIOCNXCL: | |
2570 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
2571 | return 0; | |
2572 | case TIOCGEXCL: | |
2573 | { | |
2574 | int excl = test_bit(TTY_EXCLUSIVE, &tty->flags); | |
2575 | return put_user(excl, (int __user *)p); | |
2576 | } | |
2577 | case TIOCGETD: | |
2578 | return tiocgetd(tty, p); | |
2579 | case TIOCSETD: | |
2580 | return tiocsetd(tty, p); | |
2581 | case TIOCVHANGUP: | |
2582 | if (!capable(CAP_SYS_ADMIN)) | |
2583 | return -EPERM; | |
2584 | tty_vhangup(tty); | |
2585 | return 0; | |
2586 | case TIOCGDEV: | |
2587 | { | |
2588 | unsigned int ret = new_encode_dev(tty_devnum(real_tty)); | |
2589 | return put_user(ret, (unsigned int __user *)p); | |
2590 | } | |
2591 | /* | |
2592 | * Break handling | |
2593 | */ | |
2594 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
2595 | if (tty->ops->break_ctl) | |
2596 | return tty->ops->break_ctl(tty, -1); | |
2597 | return 0; | |
2598 | case TIOCCBRK: /* Turn break off, unconditionally */ | |
2599 | if (tty->ops->break_ctl) | |
2600 | return tty->ops->break_ctl(tty, 0); | |
2601 | return 0; | |
2602 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
2603 | /* non-zero arg means wait for all output data | |
2604 | * to be sent (performed above) but don't send break. | |
2605 | * This is used by the tcdrain() termios function. | |
2606 | */ | |
2607 | if (!arg) | |
2608 | return send_break(tty, 250); | |
2609 | return 0; | |
2610 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
2611 | return send_break(tty, arg ? arg*100 : 250); | |
2612 | ||
2613 | case TIOCMGET: | |
2614 | return tty_tiocmget(tty, p); | |
2615 | case TIOCMSET: | |
2616 | case TIOCMBIC: | |
2617 | case TIOCMBIS: | |
2618 | return tty_tiocmset(tty, cmd, p); | |
2619 | case TIOCGICOUNT: | |
2620 | retval = tty_tiocgicount(tty, p); | |
2621 | /* For the moment allow fall through to the old method */ | |
2622 | if (retval != -EINVAL) | |
2623 | return retval; | |
2624 | break; | |
2625 | case TCFLSH: | |
2626 | switch (arg) { | |
2627 | case TCIFLUSH: | |
2628 | case TCIOFLUSH: | |
2629 | /* flush tty buffer and allow ldisc to process ioctl */ | |
2630 | tty_buffer_flush(tty, NULL); | |
2631 | break; | |
2632 | } | |
2633 | break; | |
2634 | case TIOCSSERIAL: | |
2635 | tty_warn_deprecated_flags(p); | |
2636 | break; | |
2637 | case TIOCGPTPEER: | |
2638 | /* Special because the struct file is needed */ | |
2639 | return ptm_open_peer(file, tty, (int)arg); | |
2640 | default: | |
2641 | retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg); | |
2642 | if (retval != -ENOIOCTLCMD) | |
2643 | return retval; | |
2644 | } | |
2645 | if (tty->ops->ioctl) { | |
2646 | retval = tty->ops->ioctl(tty, cmd, arg); | |
2647 | if (retval != -ENOIOCTLCMD) | |
2648 | return retval; | |
2649 | } | |
2650 | ld = tty_ldisc_ref_wait(tty); | |
2651 | if (!ld) | |
2652 | return hung_up_tty_ioctl(file, cmd, arg); | |
2653 | retval = -EINVAL; | |
2654 | if (ld->ops->ioctl) { | |
2655 | retval = ld->ops->ioctl(tty, file, cmd, arg); | |
2656 | if (retval == -ENOIOCTLCMD) | |
2657 | retval = -ENOTTY; | |
2658 | } | |
2659 | tty_ldisc_deref(ld); | |
2660 | return retval; | |
2661 | } | |
2662 | ||
2663 | #ifdef CONFIG_COMPAT | |
2664 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, | |
2665 | unsigned long arg) | |
2666 | { | |
2667 | struct tty_struct *tty = file_tty(file); | |
2668 | struct tty_ldisc *ld; | |
2669 | int retval = -ENOIOCTLCMD; | |
2670 | ||
2671 | if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl")) | |
2672 | return -EINVAL; | |
2673 | ||
2674 | if (tty->ops->compat_ioctl) { | |
2675 | retval = tty->ops->compat_ioctl(tty, cmd, arg); | |
2676 | if (retval != -ENOIOCTLCMD) | |
2677 | return retval; | |
2678 | } | |
2679 | ||
2680 | ld = tty_ldisc_ref_wait(tty); | |
2681 | if (!ld) | |
2682 | return hung_up_tty_compat_ioctl(file, cmd, arg); | |
2683 | if (ld->ops->compat_ioctl) | |
2684 | retval = ld->ops->compat_ioctl(tty, file, cmd, arg); | |
2685 | else | |
2686 | retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg); | |
2687 | tty_ldisc_deref(ld); | |
2688 | ||
2689 | return retval; | |
2690 | } | |
2691 | #endif | |
2692 | ||
2693 | static int this_tty(const void *t, struct file *file, unsigned fd) | |
2694 | { | |
2695 | if (likely(file->f_op->read != tty_read)) | |
2696 | return 0; | |
2697 | return file_tty(file) != t ? 0 : fd + 1; | |
2698 | } | |
2699 | ||
2700 | /* | |
2701 | * This implements the "Secure Attention Key" --- the idea is to | |
2702 | * prevent trojan horses by killing all processes associated with this | |
2703 | * tty when the user hits the "Secure Attention Key". Required for | |
2704 | * super-paranoid applications --- see the Orange Book for more details. | |
2705 | * | |
2706 | * This code could be nicer; ideally it should send a HUP, wait a few | |
2707 | * seconds, then send a INT, and then a KILL signal. But you then | |
2708 | * have to coordinate with the init process, since all processes associated | |
2709 | * with the current tty must be dead before the new getty is allowed | |
2710 | * to spawn. | |
2711 | * | |
2712 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
2713 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
2714 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
2715 | * | |
2716 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
2717 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
2718 | */ | |
2719 | void __do_SAK(struct tty_struct *tty) | |
2720 | { | |
2721 | #ifdef TTY_SOFT_SAK | |
2722 | tty_hangup(tty); | |
2723 | #else | |
2724 | struct task_struct *g, *p; | |
2725 | struct pid *session; | |
2726 | int i; | |
2727 | ||
2728 | if (!tty) | |
2729 | return; | |
2730 | session = tty->session; | |
2731 | ||
2732 | tty_ldisc_flush(tty); | |
2733 | ||
2734 | tty_driver_flush_buffer(tty); | |
2735 | ||
2736 | read_lock(&tasklist_lock); | |
2737 | /* Kill the entire session */ | |
2738 | do_each_pid_task(session, PIDTYPE_SID, p) { | |
2739 | tty_notice(tty, "SAK: killed process %d (%s): by session\n", | |
2740 | task_pid_nr(p), p->comm); | |
2741 | send_sig(SIGKILL, p, 1); | |
2742 | } while_each_pid_task(session, PIDTYPE_SID, p); | |
2743 | ||
2744 | /* Now kill any processes that happen to have the tty open */ | |
2745 | do_each_thread(g, p) { | |
2746 | if (p->signal->tty == tty) { | |
2747 | tty_notice(tty, "SAK: killed process %d (%s): by controlling tty\n", | |
2748 | task_pid_nr(p), p->comm); | |
2749 | send_sig(SIGKILL, p, 1); | |
2750 | continue; | |
2751 | } | |
2752 | task_lock(p); | |
2753 | i = iterate_fd(p->files, 0, this_tty, tty); | |
2754 | if (i != 0) { | |
2755 | tty_notice(tty, "SAK: killed process %d (%s): by fd#%d\n", | |
2756 | task_pid_nr(p), p->comm, i - 1); | |
2757 | force_sig(SIGKILL, p); | |
2758 | } | |
2759 | task_unlock(p); | |
2760 | } while_each_thread(g, p); | |
2761 | read_unlock(&tasklist_lock); | |
2762 | #endif | |
2763 | } | |
2764 | ||
2765 | static void do_SAK_work(struct work_struct *work) | |
2766 | { | |
2767 | struct tty_struct *tty = | |
2768 | container_of(work, struct tty_struct, SAK_work); | |
2769 | __do_SAK(tty); | |
2770 | } | |
2771 | ||
2772 | /* | |
2773 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
2774 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
2775 | * the values which we write to it will be identical to the values which it | |
2776 | * already has. --akpm | |
2777 | */ | |
2778 | void do_SAK(struct tty_struct *tty) | |
2779 | { | |
2780 | if (!tty) | |
2781 | return; | |
2782 | schedule_work(&tty->SAK_work); | |
2783 | } | |
2784 | ||
2785 | EXPORT_SYMBOL(do_SAK); | |
2786 | ||
2787 | static int dev_match_devt(struct device *dev, const void *data) | |
2788 | { | |
2789 | const dev_t *devt = data; | |
2790 | return dev->devt == *devt; | |
2791 | } | |
2792 | ||
2793 | /* Must put_device() after it's unused! */ | |
2794 | static struct device *tty_get_device(struct tty_struct *tty) | |
2795 | { | |
2796 | dev_t devt = tty_devnum(tty); | |
2797 | return class_find_device(tty_class, NULL, &devt, dev_match_devt); | |
2798 | } | |
2799 | ||
2800 | ||
2801 | /** | |
2802 | * alloc_tty_struct | |
2803 | * | |
2804 | * This subroutine allocates and initializes a tty structure. | |
2805 | * | |
2806 | * Locking: none - tty in question is not exposed at this point | |
2807 | */ | |
2808 | ||
2809 | struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx) | |
2810 | { | |
2811 | struct tty_struct *tty; | |
2812 | ||
2813 | tty = kzalloc(sizeof(*tty), GFP_KERNEL); | |
2814 | if (!tty) | |
2815 | return NULL; | |
2816 | ||
2817 | kref_init(&tty->kref); | |
2818 | tty->magic = TTY_MAGIC; | |
2819 | tty_ldisc_init(tty); | |
2820 | tty->session = NULL; | |
2821 | tty->pgrp = NULL; | |
2822 | mutex_init(&tty->legacy_mutex); | |
2823 | mutex_init(&tty->throttle_mutex); | |
2824 | init_rwsem(&tty->termios_rwsem); | |
2825 | mutex_init(&tty->winsize_mutex); | |
2826 | init_ldsem(&tty->ldisc_sem); | |
2827 | init_waitqueue_head(&tty->write_wait); | |
2828 | init_waitqueue_head(&tty->read_wait); | |
2829 | INIT_WORK(&tty->hangup_work, do_tty_hangup); | |
2830 | mutex_init(&tty->atomic_write_lock); | |
2831 | spin_lock_init(&tty->ctrl_lock); | |
2832 | spin_lock_init(&tty->flow_lock); | |
2833 | spin_lock_init(&tty->files_lock); | |
2834 | INIT_LIST_HEAD(&tty->tty_files); | |
2835 | INIT_WORK(&tty->SAK_work, do_SAK_work); | |
2836 | ||
2837 | tty->driver = driver; | |
2838 | tty->ops = driver->ops; | |
2839 | tty->index = idx; | |
2840 | tty_line_name(driver, idx, tty->name); | |
2841 | tty->dev = tty_get_device(tty); | |
2842 | ||
2843 | return tty; | |
2844 | } | |
2845 | ||
2846 | /** | |
2847 | * tty_put_char - write one character to a tty | |
2848 | * @tty: tty | |
2849 | * @ch: character | |
2850 | * | |
2851 | * Write one byte to the tty using the provided put_char method | |
2852 | * if present. Returns the number of characters successfully output. | |
2853 | * | |
2854 | * Note: the specific put_char operation in the driver layer may go | |
2855 | * away soon. Don't call it directly, use this method | |
2856 | */ | |
2857 | ||
2858 | int tty_put_char(struct tty_struct *tty, unsigned char ch) | |
2859 | { | |
2860 | if (tty->ops->put_char) | |
2861 | return tty->ops->put_char(tty, ch); | |
2862 | return tty->ops->write(tty, &ch, 1); | |
2863 | } | |
2864 | EXPORT_SYMBOL_GPL(tty_put_char); | |
2865 | ||
2866 | struct class *tty_class; | |
2867 | ||
2868 | static int tty_cdev_add(struct tty_driver *driver, dev_t dev, | |
2869 | unsigned int index, unsigned int count) | |
2870 | { | |
2871 | int err; | |
2872 | ||
2873 | /* init here, since reused cdevs cause crashes */ | |
2874 | driver->cdevs[index] = cdev_alloc(); | |
2875 | if (!driver->cdevs[index]) | |
2876 | return -ENOMEM; | |
2877 | driver->cdevs[index]->ops = &tty_fops; | |
2878 | driver->cdevs[index]->owner = driver->owner; | |
2879 | err = cdev_add(driver->cdevs[index], dev, count); | |
2880 | if (err) | |
2881 | kobject_put(&driver->cdevs[index]->kobj); | |
2882 | return err; | |
2883 | } | |
2884 | ||
2885 | /** | |
2886 | * tty_register_device - register a tty device | |
2887 | * @driver: the tty driver that describes the tty device | |
2888 | * @index: the index in the tty driver for this tty device | |
2889 | * @device: a struct device that is associated with this tty device. | |
2890 | * This field is optional, if there is no known struct device | |
2891 | * for this tty device it can be set to NULL safely. | |
2892 | * | |
2893 | * Returns a pointer to the struct device for this tty device | |
2894 | * (or ERR_PTR(-EFOO) on error). | |
2895 | * | |
2896 | * This call is required to be made to register an individual tty device | |
2897 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
2898 | * that bit is not set, this function should not be called by a tty | |
2899 | * driver. | |
2900 | * | |
2901 | * Locking: ?? | |
2902 | */ | |
2903 | ||
2904 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, | |
2905 | struct device *device) | |
2906 | { | |
2907 | return tty_register_device_attr(driver, index, device, NULL, NULL); | |
2908 | } | |
2909 | EXPORT_SYMBOL(tty_register_device); | |
2910 | ||
2911 | static void tty_device_create_release(struct device *dev) | |
2912 | { | |
2913 | dev_dbg(dev, "releasing...\n"); | |
2914 | kfree(dev); | |
2915 | } | |
2916 | ||
2917 | /** | |
2918 | * tty_register_device_attr - register a tty device | |
2919 | * @driver: the tty driver that describes the tty device | |
2920 | * @index: the index in the tty driver for this tty device | |
2921 | * @device: a struct device that is associated with this tty device. | |
2922 | * This field is optional, if there is no known struct device | |
2923 | * for this tty device it can be set to NULL safely. | |
2924 | * @drvdata: Driver data to be set to device. | |
2925 | * @attr_grp: Attribute group to be set on device. | |
2926 | * | |
2927 | * Returns a pointer to the struct device for this tty device | |
2928 | * (or ERR_PTR(-EFOO) on error). | |
2929 | * | |
2930 | * This call is required to be made to register an individual tty device | |
2931 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
2932 | * that bit is not set, this function should not be called by a tty | |
2933 | * driver. | |
2934 | * | |
2935 | * Locking: ?? | |
2936 | */ | |
2937 | struct device *tty_register_device_attr(struct tty_driver *driver, | |
2938 | unsigned index, struct device *device, | |
2939 | void *drvdata, | |
2940 | const struct attribute_group **attr_grp) | |
2941 | { | |
2942 | char name[64]; | |
2943 | dev_t devt = MKDEV(driver->major, driver->minor_start) + index; | |
2944 | struct ktermios *tp; | |
2945 | struct device *dev; | |
2946 | int retval; | |
2947 | ||
2948 | if (index >= driver->num) { | |
2949 | pr_err("%s: Attempt to register invalid tty line number (%d)\n", | |
2950 | driver->name, index); | |
2951 | return ERR_PTR(-EINVAL); | |
2952 | } | |
2953 | ||
2954 | if (driver->type == TTY_DRIVER_TYPE_PTY) | |
2955 | pty_line_name(driver, index, name); | |
2956 | else | |
2957 | tty_line_name(driver, index, name); | |
2958 | ||
2959 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
2960 | if (!dev) | |
2961 | return ERR_PTR(-ENOMEM); | |
2962 | ||
2963 | dev->devt = devt; | |
2964 | dev->class = tty_class; | |
2965 | dev->parent = device; | |
2966 | dev->release = tty_device_create_release; | |
2967 | dev_set_name(dev, "%s", name); | |
2968 | dev->groups = attr_grp; | |
2969 | dev_set_drvdata(dev, drvdata); | |
2970 | ||
2971 | dev_set_uevent_suppress(dev, 1); | |
2972 | ||
2973 | retval = device_register(dev); | |
2974 | if (retval) | |
2975 | goto err_put; | |
2976 | ||
2977 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { | |
2978 | /* | |
2979 | * Free any saved termios data so that the termios state is | |
2980 | * reset when reusing a minor number. | |
2981 | */ | |
2982 | tp = driver->termios[index]; | |
2983 | if (tp) { | |
2984 | driver->termios[index] = NULL; | |
2985 | kfree(tp); | |
2986 | } | |
2987 | ||
2988 | retval = tty_cdev_add(driver, devt, index, 1); | |
2989 | if (retval) | |
2990 | goto err_del; | |
2991 | } | |
2992 | ||
2993 | dev_set_uevent_suppress(dev, 0); | |
2994 | kobject_uevent(&dev->kobj, KOBJ_ADD); | |
2995 | ||
2996 | return dev; | |
2997 | ||
2998 | err_del: | |
2999 | device_del(dev); | |
3000 | err_put: | |
3001 | put_device(dev); | |
3002 | ||
3003 | return ERR_PTR(retval); | |
3004 | } | |
3005 | EXPORT_SYMBOL_GPL(tty_register_device_attr); | |
3006 | ||
3007 | /** | |
3008 | * tty_unregister_device - unregister a tty device | |
3009 | * @driver: the tty driver that describes the tty device | |
3010 | * @index: the index in the tty driver for this tty device | |
3011 | * | |
3012 | * If a tty device is registered with a call to tty_register_device() then | |
3013 | * this function must be called when the tty device is gone. | |
3014 | * | |
3015 | * Locking: ?? | |
3016 | */ | |
3017 | ||
3018 | void tty_unregister_device(struct tty_driver *driver, unsigned index) | |
3019 | { | |
3020 | device_destroy(tty_class, | |
3021 | MKDEV(driver->major, driver->minor_start) + index); | |
3022 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) { | |
3023 | cdev_del(driver->cdevs[index]); | |
3024 | driver->cdevs[index] = NULL; | |
3025 | } | |
3026 | } | |
3027 | EXPORT_SYMBOL(tty_unregister_device); | |
3028 | ||
3029 | /** | |
3030 | * __tty_alloc_driver -- allocate tty driver | |
3031 | * @lines: count of lines this driver can handle at most | |
3032 | * @owner: module which is responsible for this driver | |
3033 | * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags | |
3034 | * | |
3035 | * This should not be called directly, some of the provided macros should be | |
3036 | * used instead. Use IS_ERR and friends on @retval. | |
3037 | */ | |
3038 | struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, | |
3039 | unsigned long flags) | |
3040 | { | |
3041 | struct tty_driver *driver; | |
3042 | unsigned int cdevs = 1; | |
3043 | int err; | |
3044 | ||
3045 | if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1)) | |
3046 | return ERR_PTR(-EINVAL); | |
3047 | ||
3048 | driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); | |
3049 | if (!driver) | |
3050 | return ERR_PTR(-ENOMEM); | |
3051 | ||
3052 | kref_init(&driver->kref); | |
3053 | driver->magic = TTY_DRIVER_MAGIC; | |
3054 | driver->num = lines; | |
3055 | driver->owner = owner; | |
3056 | driver->flags = flags; | |
3057 | ||
3058 | if (!(flags & TTY_DRIVER_DEVPTS_MEM)) { | |
3059 | driver->ttys = kcalloc(lines, sizeof(*driver->ttys), | |
3060 | GFP_KERNEL); | |
3061 | driver->termios = kcalloc(lines, sizeof(*driver->termios), | |
3062 | GFP_KERNEL); | |
3063 | if (!driver->ttys || !driver->termios) { | |
3064 | err = -ENOMEM; | |
3065 | goto err_free_all; | |
3066 | } | |
3067 | } | |
3068 | ||
3069 | if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) { | |
3070 | driver->ports = kcalloc(lines, sizeof(*driver->ports), | |
3071 | GFP_KERNEL); | |
3072 | if (!driver->ports) { | |
3073 | err = -ENOMEM; | |
3074 | goto err_free_all; | |
3075 | } | |
3076 | cdevs = lines; | |
3077 | } | |
3078 | ||
3079 | driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL); | |
3080 | if (!driver->cdevs) { | |
3081 | err = -ENOMEM; | |
3082 | goto err_free_all; | |
3083 | } | |
3084 | ||
3085 | return driver; | |
3086 | err_free_all: | |
3087 | kfree(driver->ports); | |
3088 | kfree(driver->ttys); | |
3089 | kfree(driver->termios); | |
3090 | kfree(driver->cdevs); | |
3091 | kfree(driver); | |
3092 | return ERR_PTR(err); | |
3093 | } | |
3094 | EXPORT_SYMBOL(__tty_alloc_driver); | |
3095 | ||
3096 | static void destruct_tty_driver(struct kref *kref) | |
3097 | { | |
3098 | struct tty_driver *driver = container_of(kref, struct tty_driver, kref); | |
3099 | int i; | |
3100 | struct ktermios *tp; | |
3101 | ||
3102 | if (driver->flags & TTY_DRIVER_INSTALLED) { | |
3103 | for (i = 0; i < driver->num; i++) { | |
3104 | tp = driver->termios[i]; | |
3105 | if (tp) { | |
3106 | driver->termios[i] = NULL; | |
3107 | kfree(tp); | |
3108 | } | |
3109 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) | |
3110 | tty_unregister_device(driver, i); | |
3111 | } | |
3112 | proc_tty_unregister_driver(driver); | |
3113 | if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) | |
3114 | cdev_del(driver->cdevs[0]); | |
3115 | } | |
3116 | kfree(driver->cdevs); | |
3117 | kfree(driver->ports); | |
3118 | kfree(driver->termios); | |
3119 | kfree(driver->ttys); | |
3120 | kfree(driver); | |
3121 | } | |
3122 | ||
3123 | void tty_driver_kref_put(struct tty_driver *driver) | |
3124 | { | |
3125 | kref_put(&driver->kref, destruct_tty_driver); | |
3126 | } | |
3127 | EXPORT_SYMBOL(tty_driver_kref_put); | |
3128 | ||
3129 | void tty_set_operations(struct tty_driver *driver, | |
3130 | const struct tty_operations *op) | |
3131 | { | |
3132 | driver->ops = op; | |
3133 | }; | |
3134 | EXPORT_SYMBOL(tty_set_operations); | |
3135 | ||
3136 | void put_tty_driver(struct tty_driver *d) | |
3137 | { | |
3138 | tty_driver_kref_put(d); | |
3139 | } | |
3140 | EXPORT_SYMBOL(put_tty_driver); | |
3141 | ||
3142 | /* | |
3143 | * Called by a tty driver to register itself. | |
3144 | */ | |
3145 | int tty_register_driver(struct tty_driver *driver) | |
3146 | { | |
3147 | int error; | |
3148 | int i; | |
3149 | dev_t dev; | |
3150 | struct device *d; | |
3151 | ||
3152 | if (!driver->major) { | |
3153 | error = alloc_chrdev_region(&dev, driver->minor_start, | |
3154 | driver->num, driver->name); | |
3155 | if (!error) { | |
3156 | driver->major = MAJOR(dev); | |
3157 | driver->minor_start = MINOR(dev); | |
3158 | } | |
3159 | } else { | |
3160 | dev = MKDEV(driver->major, driver->minor_start); | |
3161 | error = register_chrdev_region(dev, driver->num, driver->name); | |
3162 | } | |
3163 | if (error < 0) | |
3164 | goto err; | |
3165 | ||
3166 | if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) { | |
3167 | error = tty_cdev_add(driver, dev, 0, driver->num); | |
3168 | if (error) | |
3169 | goto err_unreg_char; | |
3170 | } | |
3171 | ||
3172 | mutex_lock(&tty_mutex); | |
3173 | list_add(&driver->tty_drivers, &tty_drivers); | |
3174 | mutex_unlock(&tty_mutex); | |
3175 | ||
3176 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { | |
3177 | for (i = 0; i < driver->num; i++) { | |
3178 | d = tty_register_device(driver, i, NULL); | |
3179 | if (IS_ERR(d)) { | |
3180 | error = PTR_ERR(d); | |
3181 | goto err_unreg_devs; | |
3182 | } | |
3183 | } | |
3184 | } | |
3185 | proc_tty_register_driver(driver); | |
3186 | driver->flags |= TTY_DRIVER_INSTALLED; | |
3187 | return 0; | |
3188 | ||
3189 | err_unreg_devs: | |
3190 | for (i--; i >= 0; i--) | |
3191 | tty_unregister_device(driver, i); | |
3192 | ||
3193 | mutex_lock(&tty_mutex); | |
3194 | list_del(&driver->tty_drivers); | |
3195 | mutex_unlock(&tty_mutex); | |
3196 | ||
3197 | err_unreg_char: | |
3198 | unregister_chrdev_region(dev, driver->num); | |
3199 | err: | |
3200 | return error; | |
3201 | } | |
3202 | EXPORT_SYMBOL(tty_register_driver); | |
3203 | ||
3204 | /* | |
3205 | * Called by a tty driver to unregister itself. | |
3206 | */ | |
3207 | int tty_unregister_driver(struct tty_driver *driver) | |
3208 | { | |
3209 | #if 0 | |
3210 | /* FIXME */ | |
3211 | if (driver->refcount) | |
3212 | return -EBUSY; | |
3213 | #endif | |
3214 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
3215 | driver->num); | |
3216 | mutex_lock(&tty_mutex); | |
3217 | list_del(&driver->tty_drivers); | |
3218 | mutex_unlock(&tty_mutex); | |
3219 | return 0; | |
3220 | } | |
3221 | ||
3222 | EXPORT_SYMBOL(tty_unregister_driver); | |
3223 | ||
3224 | dev_t tty_devnum(struct tty_struct *tty) | |
3225 | { | |
3226 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
3227 | } | |
3228 | EXPORT_SYMBOL(tty_devnum); | |
3229 | ||
3230 | void tty_default_fops(struct file_operations *fops) | |
3231 | { | |
3232 | *fops = tty_fops; | |
3233 | } | |
3234 | ||
3235 | static char *tty_devnode(struct device *dev, umode_t *mode) | |
3236 | { | |
3237 | if (!mode) | |
3238 | return NULL; | |
3239 | if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) || | |
3240 | dev->devt == MKDEV(TTYAUX_MAJOR, 2)) | |
3241 | *mode = 0666; | |
3242 | return NULL; | |
3243 | } | |
3244 | ||
3245 | static int __init tty_class_init(void) | |
3246 | { | |
3247 | tty_class = class_create(THIS_MODULE, "tty"); | |
3248 | if (IS_ERR(tty_class)) | |
3249 | return PTR_ERR(tty_class); | |
3250 | tty_class->devnode = tty_devnode; | |
3251 | return 0; | |
3252 | } | |
3253 | ||
3254 | postcore_initcall(tty_class_init); | |
3255 | ||
3256 | /* 3/2004 jmc: why do these devices exist? */ | |
3257 | static struct cdev tty_cdev, console_cdev; | |
3258 | ||
3259 | static ssize_t show_cons_active(struct device *dev, | |
3260 | struct device_attribute *attr, char *buf) | |
3261 | { | |
3262 | struct console *cs[16]; | |
3263 | int i = 0; | |
3264 | struct console *c; | |
3265 | ssize_t count = 0; | |
3266 | ||
3267 | console_lock(); | |
3268 | for_each_console(c) { | |
3269 | if (!c->device) | |
3270 | continue; | |
3271 | if (!c->write) | |
3272 | continue; | |
3273 | if ((c->flags & CON_ENABLED) == 0) | |
3274 | continue; | |
3275 | cs[i++] = c; | |
3276 | if (i >= ARRAY_SIZE(cs)) | |
3277 | break; | |
3278 | } | |
3279 | while (i--) { | |
3280 | int index = cs[i]->index; | |
3281 | struct tty_driver *drv = cs[i]->device(cs[i], &index); | |
3282 | ||
3283 | /* don't resolve tty0 as some programs depend on it */ | |
3284 | if (drv && (cs[i]->index > 0 || drv->major != TTY_MAJOR)) | |
3285 | count += tty_line_name(drv, index, buf + count); | |
3286 | else | |
3287 | count += sprintf(buf + count, "%s%d", | |
3288 | cs[i]->name, cs[i]->index); | |
3289 | ||
3290 | count += sprintf(buf + count, "%c", i ? ' ':'\n'); | |
3291 | } | |
3292 | console_unlock(); | |
3293 | ||
3294 | return count; | |
3295 | } | |
3296 | static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL); | |
3297 | ||
3298 | static struct attribute *cons_dev_attrs[] = { | |
3299 | &dev_attr_active.attr, | |
3300 | NULL | |
3301 | }; | |
3302 | ||
3303 | ATTRIBUTE_GROUPS(cons_dev); | |
3304 | ||
3305 | static struct device *consdev; | |
3306 | ||
3307 | void console_sysfs_notify(void) | |
3308 | { | |
3309 | if (consdev) | |
3310 | sysfs_notify(&consdev->kobj, NULL, "active"); | |
3311 | } | |
3312 | ||
3313 | /* | |
3314 | * Ok, now we can initialize the rest of the tty devices and can count | |
3315 | * on memory allocations, interrupts etc.. | |
3316 | */ | |
3317 | int __init tty_init(void) | |
3318 | { | |
3319 | cdev_init(&tty_cdev, &tty_fops); | |
3320 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
3321 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
3322 | panic("Couldn't register /dev/tty driver\n"); | |
3323 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty"); | |
3324 | ||
3325 | cdev_init(&console_cdev, &console_fops); | |
3326 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
3327 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
3328 | panic("Couldn't register /dev/console driver\n"); | |
3329 | consdev = device_create_with_groups(tty_class, NULL, | |
3330 | MKDEV(TTYAUX_MAJOR, 1), NULL, | |
3331 | cons_dev_groups, "console"); | |
3332 | if (IS_ERR(consdev)) | |
3333 | consdev = NULL; | |
3334 | ||
3335 | #ifdef CONFIG_VT | |
3336 | vty_init(&console_fops); | |
3337 | #endif | |
3338 | return 0; | |
3339 | } | |
3340 |