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