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1da177e4 LT |
1 | /* |
2 | * linux/drivers/char/tty_io.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles | |
9 | * or rs-channels. It also implements echoing, cooked mode etc. | |
10 | * | |
11 | * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. | |
12 | * | |
13 | * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the | |
14 | * tty_struct and tty_queue structures. Previously there was an array | |
15 | * of 256 tty_struct's which was statically allocated, and the | |
16 | * tty_queue structures were allocated at boot time. Both are now | |
17 | * dynamically allocated only when the tty is open. | |
18 | * | |
19 | * Also restructured routines so that there is more of a separation | |
20 | * between the high-level tty routines (tty_io.c and tty_ioctl.c) and | |
21 | * the low-level tty routines (serial.c, pty.c, console.c). This | |
22 | * makes for cleaner and more compact code. -TYT, 9/17/92 | |
23 | * | |
24 | * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines | |
25 | * which can be dynamically activated and de-activated by the line | |
26 | * discipline handling modules (like SLIP). | |
27 | * | |
28 | * NOTE: pay no attention to the line discipline code (yet); its | |
29 | * interface is still subject to change in this version... | |
30 | * -- TYT, 1/31/92 | |
31 | * | |
32 | * Added functionality to the OPOST tty handling. No delays, but all | |
33 | * other bits should be there. | |
34 | * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. | |
35 | * | |
36 | * Rewrote canonical mode and added more termios flags. | |
37 | * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 | |
38 | * | |
39 | * Reorganized FASYNC support so mouse code can share it. | |
40 | * -- ctm@ardi.com, 9Sep95 | |
41 | * | |
42 | * New TIOCLINUX variants added. | |
43 | * -- mj@k332.feld.cvut.cz, 19-Nov-95 | |
44 | * | |
45 | * Restrict vt switching via ioctl() | |
46 | * -- grif@cs.ucr.edu, 5-Dec-95 | |
47 | * | |
48 | * Move console and virtual terminal code to more appropriate files, | |
49 | * implement CONFIG_VT and generalize console device interface. | |
50 | * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 | |
51 | * | |
52 | * Rewrote init_dev and release_dev to eliminate races. | |
53 | * -- Bill Hawes <whawes@star.net>, June 97 | |
54 | * | |
55 | * Added devfs support. | |
56 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 | |
57 | * | |
58 | * Added support for a Unix98-style ptmx device. | |
59 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 | |
60 | * | |
61 | * Reduced memory usage for older ARM systems | |
62 | * -- Russell King <rmk@arm.linux.org.uk> | |
63 | * | |
64 | * Move do_SAK() into process context. Less stack use in devfs functions. | |
65 | * alloc_tty_struct() always uses kmalloc() -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 | |
66 | */ | |
67 | ||
1da177e4 LT |
68 | #include <linux/types.h> |
69 | #include <linux/major.h> | |
70 | #include <linux/errno.h> | |
71 | #include <linux/signal.h> | |
72 | #include <linux/fcntl.h> | |
73 | #include <linux/sched.h> | |
74 | #include <linux/interrupt.h> | |
75 | #include <linux/tty.h> | |
76 | #include <linux/tty_driver.h> | |
77 | #include <linux/tty_flip.h> | |
78 | #include <linux/devpts_fs.h> | |
79 | #include <linux/file.h> | |
80 | #include <linux/console.h> | |
81 | #include <linux/timer.h> | |
82 | #include <linux/ctype.h> | |
83 | #include <linux/kd.h> | |
84 | #include <linux/mm.h> | |
85 | #include <linux/string.h> | |
86 | #include <linux/slab.h> | |
87 | #include <linux/poll.h> | |
88 | #include <linux/proc_fs.h> | |
89 | #include <linux/init.h> | |
90 | #include <linux/module.h> | |
91 | #include <linux/smp_lock.h> | |
92 | #include <linux/device.h> | |
93 | #include <linux/idr.h> | |
94 | #include <linux/wait.h> | |
95 | #include <linux/bitops.h> | |
b20f3ae5 | 96 | #include <linux/delay.h> |
1da177e4 LT |
97 | |
98 | #include <asm/uaccess.h> | |
99 | #include <asm/system.h> | |
100 | ||
101 | #include <linux/kbd_kern.h> | |
102 | #include <linux/vt_kern.h> | |
103 | #include <linux/selection.h> | |
1da177e4 LT |
104 | |
105 | #include <linux/kmod.h> | |
106 | ||
107 | #undef TTY_DEBUG_HANGUP | |
108 | ||
109 | #define TTY_PARANOIA_CHECK 1 | |
110 | #define CHECK_TTY_COUNT 1 | |
111 | ||
edc6afc5 | 112 | struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ |
1da177e4 LT |
113 | .c_iflag = ICRNL | IXON, |
114 | .c_oflag = OPOST | ONLCR, | |
115 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, | |
116 | .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | | |
117 | ECHOCTL | ECHOKE | IEXTEN, | |
edc6afc5 AC |
118 | .c_cc = INIT_C_CC, |
119 | .c_ispeed = 38400, | |
120 | .c_ospeed = 38400 | |
1da177e4 LT |
121 | }; |
122 | ||
123 | EXPORT_SYMBOL(tty_std_termios); | |
124 | ||
125 | /* This list gets poked at by procfs and various bits of boot up code. This | |
126 | could do with some rationalisation such as pulling the tty proc function | |
127 | into this file */ | |
128 | ||
129 | LIST_HEAD(tty_drivers); /* linked list of tty drivers */ | |
130 | ||
24ec839c | 131 | /* Mutex to protect creating and releasing a tty. This is shared with |
1da177e4 | 132 | vt.c for deeply disgusting hack reasons */ |
70522e12 | 133 | DEFINE_MUTEX(tty_mutex); |
de2a84f2 | 134 | EXPORT_SYMBOL(tty_mutex); |
1da177e4 LT |
135 | |
136 | #ifdef CONFIG_UNIX98_PTYS | |
137 | extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ | |
138 | extern int pty_limit; /* Config limit on Unix98 ptys */ | |
139 | static DEFINE_IDR(allocated_ptys); | |
140 | static DECLARE_MUTEX(allocated_ptys_lock); | |
141 | static int ptmx_open(struct inode *, struct file *); | |
142 | #endif | |
143 | ||
144 | extern void disable_early_printk(void); | |
145 | ||
146 | static void initialize_tty_struct(struct tty_struct *tty); | |
147 | ||
148 | static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); | |
149 | static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); | |
150 | ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); | |
151 | static unsigned int tty_poll(struct file *, poll_table *); | |
152 | static int tty_open(struct inode *, struct file *); | |
153 | static int tty_release(struct inode *, struct file *); | |
154 | int tty_ioctl(struct inode * inode, struct file * file, | |
155 | unsigned int cmd, unsigned long arg); | |
156 | static int tty_fasync(int fd, struct file * filp, int on); | |
d5698c28 | 157 | static void release_tty(struct tty_struct *tty, int idx); |
cdc62330 | 158 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
1da177e4 | 159 | |
af9b897e AC |
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 | |
af9b897e | 167 | */ |
1da177e4 LT |
168 | |
169 | static struct tty_struct *alloc_tty_struct(void) | |
170 | { | |
1266b1e1 | 171 | return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); |
1da177e4 LT |
172 | } |
173 | ||
33f0f88f AC |
174 | static void tty_buffer_free_all(struct tty_struct *); |
175 | ||
af9b897e AC |
176 | /** |
177 | * free_tty_struct - free a disused tty | |
178 | * @tty: tty struct to free | |
179 | * | |
180 | * Free the write buffers, tty queue and tty memory itself. | |
181 | * | |
182 | * Locking: none. Must be called after tty is definitely unused | |
183 | */ | |
184 | ||
1da177e4 LT |
185 | static inline void free_tty_struct(struct tty_struct *tty) |
186 | { | |
187 | kfree(tty->write_buf); | |
33f0f88f | 188 | tty_buffer_free_all(tty); |
1da177e4 LT |
189 | kfree(tty); |
190 | } | |
191 | ||
192 | #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) | |
193 | ||
af9b897e AC |
194 | /** |
195 | * tty_name - return tty naming | |
196 | * @tty: tty structure | |
197 | * @buf: buffer for output | |
198 | * | |
199 | * Convert a tty structure into a name. The name reflects the kernel | |
200 | * naming policy and if udev is in use may not reflect user space | |
201 | * | |
202 | * Locking: none | |
203 | */ | |
204 | ||
1da177e4 LT |
205 | char *tty_name(struct tty_struct *tty, char *buf) |
206 | { | |
207 | if (!tty) /* Hmm. NULL pointer. That's fun. */ | |
208 | strcpy(buf, "NULL tty"); | |
209 | else | |
210 | strcpy(buf, tty->name); | |
211 | return buf; | |
212 | } | |
213 | ||
214 | EXPORT_SYMBOL(tty_name); | |
215 | ||
d769a669 | 216 | int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, |
1da177e4 LT |
217 | const char *routine) |
218 | { | |
219 | #ifdef TTY_PARANOIA_CHECK | |
220 | if (!tty) { | |
221 | printk(KERN_WARNING | |
222 | "null TTY for (%d:%d) in %s\n", | |
223 | imajor(inode), iminor(inode), routine); | |
224 | return 1; | |
225 | } | |
226 | if (tty->magic != TTY_MAGIC) { | |
227 | printk(KERN_WARNING | |
228 | "bad magic number for tty struct (%d:%d) in %s\n", | |
229 | imajor(inode), iminor(inode), routine); | |
230 | return 1; | |
231 | } | |
232 | #endif | |
233 | return 0; | |
234 | } | |
235 | ||
236 | static int check_tty_count(struct tty_struct *tty, const char *routine) | |
237 | { | |
238 | #ifdef CHECK_TTY_COUNT | |
239 | struct list_head *p; | |
240 | int count = 0; | |
241 | ||
242 | file_list_lock(); | |
243 | list_for_each(p, &tty->tty_files) { | |
244 | count++; | |
245 | } | |
246 | file_list_unlock(); | |
247 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
248 | tty->driver->subtype == PTY_TYPE_SLAVE && | |
249 | tty->link && tty->link->count) | |
250 | count++; | |
251 | if (tty->count != count) { | |
252 | printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " | |
253 | "!= #fd's(%d) in %s\n", | |
254 | tty->name, tty->count, count, routine); | |
255 | return count; | |
24ec839c | 256 | } |
1da177e4 LT |
257 | #endif |
258 | return 0; | |
259 | } | |
260 | ||
33f0f88f AC |
261 | /* |
262 | * Tty buffer allocation management | |
263 | */ | |
264 | ||
af9b897e AC |
265 | /** |
266 | * tty_buffer_free_all - free buffers used by a tty | |
267 | * @tty: tty to free from | |
268 | * | |
269 | * Remove all the buffers pending on a tty whether queued with data | |
270 | * or in the free ring. Must be called when the tty is no longer in use | |
271 | * | |
272 | * Locking: none | |
273 | */ | |
274 | ||
33f0f88f AC |
275 | static void tty_buffer_free_all(struct tty_struct *tty) |
276 | { | |
277 | struct tty_buffer *thead; | |
278 | while((thead = tty->buf.head) != NULL) { | |
279 | tty->buf.head = thead->next; | |
280 | kfree(thead); | |
281 | } | |
282 | while((thead = tty->buf.free) != NULL) { | |
283 | tty->buf.free = thead->next; | |
284 | kfree(thead); | |
285 | } | |
286 | tty->buf.tail = NULL; | |
01da5fd8 | 287 | tty->buf.memory_used = 0; |
33f0f88f AC |
288 | } |
289 | ||
01da5fd8 AC |
290 | /** |
291 | * tty_buffer_init - prepare a tty buffer structure | |
292 | * @tty: tty to initialise | |
293 | * | |
294 | * Set up the initial state of the buffer management for a tty device. | |
295 | * Must be called before the other tty buffer functions are used. | |
296 | * | |
297 | * Locking: none | |
298 | */ | |
299 | ||
33f0f88f AC |
300 | static void tty_buffer_init(struct tty_struct *tty) |
301 | { | |
808249ce | 302 | spin_lock_init(&tty->buf.lock); |
33f0f88f AC |
303 | tty->buf.head = NULL; |
304 | tty->buf.tail = NULL; | |
305 | tty->buf.free = NULL; | |
01da5fd8 | 306 | tty->buf.memory_used = 0; |
33f0f88f AC |
307 | } |
308 | ||
01da5fd8 AC |
309 | /** |
310 | * tty_buffer_alloc - allocate a tty buffer | |
311 | * @tty: tty device | |
312 | * @size: desired size (characters) | |
313 | * | |
314 | * Allocate a new tty buffer to hold the desired number of characters. | |
315 | * Return NULL if out of memory or the allocation would exceed the | |
316 | * per device queue | |
317 | * | |
318 | * Locking: Caller must hold tty->buf.lock | |
319 | */ | |
320 | ||
321 | static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) | |
33f0f88f | 322 | { |
01da5fd8 AC |
323 | struct tty_buffer *p; |
324 | ||
325 | if (tty->buf.memory_used + size > 65536) | |
326 | return NULL; | |
327 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); | |
33f0f88f AC |
328 | if(p == NULL) |
329 | return NULL; | |
330 | p->used = 0; | |
331 | p->size = size; | |
332 | p->next = NULL; | |
8977d929 PF |
333 | p->commit = 0; |
334 | p->read = 0; | |
33f0f88f AC |
335 | p->char_buf_ptr = (char *)(p->data); |
336 | p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; | |
01da5fd8 | 337 | tty->buf.memory_used += size; |
33f0f88f AC |
338 | return p; |
339 | } | |
340 | ||
01da5fd8 AC |
341 | /** |
342 | * tty_buffer_free - free a tty buffer | |
343 | * @tty: tty owning the buffer | |
344 | * @b: the buffer to free | |
345 | * | |
346 | * Free a tty buffer, or add it to the free list according to our | |
347 | * internal strategy | |
348 | * | |
349 | * Locking: Caller must hold tty->buf.lock | |
350 | */ | |
33f0f88f AC |
351 | |
352 | static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) | |
353 | { | |
354 | /* Dumb strategy for now - should keep some stats */ | |
01da5fd8 AC |
355 | tty->buf.memory_used -= b->size; |
356 | WARN_ON(tty->buf.memory_used < 0); | |
357 | ||
33f0f88f AC |
358 | if(b->size >= 512) |
359 | kfree(b); | |
360 | else { | |
361 | b->next = tty->buf.free; | |
362 | tty->buf.free = b; | |
363 | } | |
364 | } | |
365 | ||
01da5fd8 AC |
366 | /** |
367 | * tty_buffer_find - find a free tty buffer | |
368 | * @tty: tty owning the buffer | |
369 | * @size: characters wanted | |
370 | * | |
371 | * Locate an existing suitable tty buffer or if we are lacking one then | |
372 | * allocate a new one. We round our buffers off in 256 character chunks | |
373 | * to get better allocation behaviour. | |
374 | * | |
375 | * Locking: Caller must hold tty->buf.lock | |
376 | */ | |
377 | ||
33f0f88f AC |
378 | static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) |
379 | { | |
380 | struct tty_buffer **tbh = &tty->buf.free; | |
381 | while((*tbh) != NULL) { | |
382 | struct tty_buffer *t = *tbh; | |
383 | if(t->size >= size) { | |
384 | *tbh = t->next; | |
385 | t->next = NULL; | |
386 | t->used = 0; | |
8977d929 PF |
387 | t->commit = 0; |
388 | t->read = 0; | |
01da5fd8 | 389 | tty->buf.memory_used += t->size; |
33f0f88f AC |
390 | return t; |
391 | } | |
392 | tbh = &((*tbh)->next); | |
393 | } | |
394 | /* Round the buffer size out */ | |
395 | size = (size + 0xFF) & ~ 0xFF; | |
01da5fd8 | 396 | return tty_buffer_alloc(tty, size); |
33f0f88f AC |
397 | /* Should possibly check if this fails for the largest buffer we |
398 | have queued and recycle that ? */ | |
399 | } | |
400 | ||
01da5fd8 AC |
401 | /** |
402 | * tty_buffer_request_room - grow tty buffer if needed | |
403 | * @tty: tty structure | |
404 | * @size: size desired | |
405 | * | |
406 | * Make at least size bytes of linear space available for the tty | |
407 | * buffer. If we fail return the size we managed to find. | |
408 | * | |
409 | * Locking: Takes tty->buf.lock | |
410 | */ | |
33f0f88f AC |
411 | int tty_buffer_request_room(struct tty_struct *tty, size_t size) |
412 | { | |
808249ce PF |
413 | struct tty_buffer *b, *n; |
414 | int left; | |
415 | unsigned long flags; | |
416 | ||
417 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33f0f88f AC |
418 | |
419 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to | |
420 | remove this conditional if its worth it. This would be invisible | |
421 | to the callers */ | |
33b37a33 | 422 | if ((b = tty->buf.tail) != NULL) |
33f0f88f | 423 | left = b->size - b->used; |
33b37a33 | 424 | else |
808249ce PF |
425 | left = 0; |
426 | ||
427 | if (left < size) { | |
428 | /* This is the slow path - looking for new buffers to use */ | |
429 | if ((n = tty_buffer_find(tty, size)) != NULL) { | |
430 | if (b != NULL) { | |
431 | b->next = n; | |
8977d929 | 432 | b->commit = b->used; |
808249ce PF |
433 | } else |
434 | tty->buf.head = n; | |
435 | tty->buf.tail = n; | |
808249ce PF |
436 | } else |
437 | size = left; | |
438 | } | |
439 | ||
440 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
33f0f88f AC |
441 | return size; |
442 | } | |
33f0f88f AC |
443 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
444 | ||
af9b897e AC |
445 | /** |
446 | * tty_insert_flip_string - Add characters to the tty buffer | |
447 | * @tty: tty structure | |
448 | * @chars: characters | |
449 | * @size: size | |
450 | * | |
451 | * Queue a series of bytes to the tty buffering. All the characters | |
452 | * passed are marked as without error. Returns the number added. | |
453 | * | |
454 | * Locking: Called functions may take tty->buf.lock | |
455 | */ | |
456 | ||
e1a25090 AM |
457 | int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, |
458 | size_t size) | |
33f0f88f AC |
459 | { |
460 | int copied = 0; | |
461 | do { | |
462 | int space = tty_buffer_request_room(tty, size - copied); | |
463 | struct tty_buffer *tb = tty->buf.tail; | |
464 | /* If there is no space then tb may be NULL */ | |
465 | if(unlikely(space == 0)) | |
466 | break; | |
467 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
468 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
469 | tb->used += space; | |
470 | copied += space; | |
471 | chars += space; | |
527063ba AD |
472 | /* There is a small chance that we need to split the data over |
473 | several buffers. If this is the case we must loop */ | |
474 | } while (unlikely(size > copied)); | |
33f0f88f AC |
475 | return copied; |
476 | } | |
ee37df78 | 477 | EXPORT_SYMBOL(tty_insert_flip_string); |
33f0f88f | 478 | |
af9b897e AC |
479 | /** |
480 | * tty_insert_flip_string_flags - Add characters to the tty buffer | |
481 | * @tty: tty structure | |
482 | * @chars: characters | |
483 | * @flags: flag bytes | |
484 | * @size: size | |
485 | * | |
486 | * Queue a series of bytes to the tty buffering. For each character | |
487 | * the flags array indicates the status of the character. Returns the | |
488 | * number added. | |
489 | * | |
490 | * Locking: Called functions may take tty->buf.lock | |
491 | */ | |
492 | ||
e1a25090 AM |
493 | int tty_insert_flip_string_flags(struct tty_struct *tty, |
494 | const unsigned char *chars, const char *flags, size_t size) | |
33f0f88f AC |
495 | { |
496 | int copied = 0; | |
497 | do { | |
498 | int space = tty_buffer_request_room(tty, size - copied); | |
499 | struct tty_buffer *tb = tty->buf.tail; | |
500 | /* If there is no space then tb may be NULL */ | |
501 | if(unlikely(space == 0)) | |
502 | break; | |
503 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
504 | memcpy(tb->flag_buf_ptr + tb->used, flags, space); | |
505 | tb->used += space; | |
506 | copied += space; | |
507 | chars += space; | |
508 | flags += space; | |
527063ba AD |
509 | /* There is a small chance that we need to split the data over |
510 | several buffers. If this is the case we must loop */ | |
511 | } while (unlikely(size > copied)); | |
33f0f88f AC |
512 | return copied; |
513 | } | |
ff4547f4 | 514 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
33f0f88f | 515 | |
af9b897e AC |
516 | /** |
517 | * tty_schedule_flip - push characters to ldisc | |
518 | * @tty: tty to push from | |
519 | * | |
520 | * Takes any pending buffers and transfers their ownership to the | |
521 | * ldisc side of the queue. It then schedules those characters for | |
522 | * processing by the line discipline. | |
523 | * | |
524 | * Locking: Takes tty->buf.lock | |
525 | */ | |
526 | ||
e1a25090 AM |
527 | void tty_schedule_flip(struct tty_struct *tty) |
528 | { | |
529 | unsigned long flags; | |
530 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 531 | if (tty->buf.tail != NULL) |
e1a25090 | 532 | tty->buf.tail->commit = tty->buf.tail->used; |
e1a25090 AM |
533 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
534 | schedule_delayed_work(&tty->buf.work, 1); | |
535 | } | |
536 | EXPORT_SYMBOL(tty_schedule_flip); | |
33f0f88f | 537 | |
af9b897e AC |
538 | /** |
539 | * tty_prepare_flip_string - make room for characters | |
540 | * @tty: tty | |
541 | * @chars: return pointer for character write area | |
542 | * @size: desired size | |
543 | * | |
33f0f88f AC |
544 | * Prepare a block of space in the buffer for data. Returns the length |
545 | * available and buffer pointer to the space which is now allocated and | |
546 | * accounted for as ready for normal characters. This is used for drivers | |
547 | * that need their own block copy routines into the buffer. There is no | |
548 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
549 | * |
550 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
551 | */ |
552 | ||
553 | int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size) | |
554 | { | |
555 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
556 | if (likely(space)) { |
557 | struct tty_buffer *tb = tty->buf.tail; | |
558 | *chars = tb->char_buf_ptr + tb->used; | |
559 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
560 | tb->used += space; | |
561 | } | |
33f0f88f AC |
562 | return space; |
563 | } | |
564 | ||
565 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); | |
566 | ||
af9b897e AC |
567 | /** |
568 | * tty_prepare_flip_string_flags - make room for characters | |
569 | * @tty: tty | |
570 | * @chars: return pointer for character write area | |
571 | * @flags: return pointer for status flag write area | |
572 | * @size: desired size | |
573 | * | |
33f0f88f AC |
574 | * Prepare a block of space in the buffer for data. Returns the length |
575 | * available and buffer pointer to the space which is now allocated and | |
576 | * accounted for as ready for characters. This is used for drivers | |
577 | * that need their own block copy routines into the buffer. There is no | |
578 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
579 | * |
580 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
581 | */ |
582 | ||
583 | int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size) | |
584 | { | |
585 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
586 | if (likely(space)) { |
587 | struct tty_buffer *tb = tty->buf.tail; | |
588 | *chars = tb->char_buf_ptr + tb->used; | |
589 | *flags = tb->flag_buf_ptr + tb->used; | |
590 | tb->used += space; | |
591 | } | |
33f0f88f AC |
592 | return space; |
593 | } | |
594 | ||
595 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); | |
596 | ||
597 | ||
598 | ||
af9b897e AC |
599 | /** |
600 | * tty_set_termios_ldisc - set ldisc field | |
601 | * @tty: tty structure | |
602 | * @num: line discipline number | |
603 | * | |
1da177e4 LT |
604 | * This is probably overkill for real world processors but |
605 | * they are not on hot paths so a little discipline won't do | |
606 | * any harm. | |
af9b897e | 607 | * |
24ec839c | 608 | * Locking: takes termios_mutex |
1da177e4 LT |
609 | */ |
610 | ||
611 | static void tty_set_termios_ldisc(struct tty_struct *tty, int num) | |
612 | { | |
5785c95b | 613 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 614 | tty->termios->c_line = num; |
5785c95b | 615 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
616 | } |
617 | ||
618 | /* | |
619 | * This guards the refcounted line discipline lists. The lock | |
620 | * must be taken with irqs off because there are hangup path | |
621 | * callers who will do ldisc lookups and cannot sleep. | |
622 | */ | |
623 | ||
624 | static DEFINE_SPINLOCK(tty_ldisc_lock); | |
625 | static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); | |
bfb07599 | 626 | static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */ |
1da177e4 | 627 | |
af9b897e AC |
628 | /** |
629 | * tty_register_ldisc - install a line discipline | |
630 | * @disc: ldisc number | |
631 | * @new_ldisc: pointer to the ldisc object | |
632 | * | |
633 | * Installs a new line discipline into the kernel. The discipline | |
634 | * is set up as unreferenced and then made available to the kernel | |
635 | * from this point onwards. | |
636 | * | |
637 | * Locking: | |
638 | * takes tty_ldisc_lock to guard against ldisc races | |
639 | */ | |
640 | ||
1da177e4 LT |
641 | int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) |
642 | { | |
643 | unsigned long flags; | |
644 | int ret = 0; | |
645 | ||
646 | if (disc < N_TTY || disc >= NR_LDISCS) | |
647 | return -EINVAL; | |
648 | ||
649 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
bfb07599 AD |
650 | tty_ldiscs[disc] = *new_ldisc; |
651 | tty_ldiscs[disc].num = disc; | |
652 | tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; | |
653 | tty_ldiscs[disc].refcount = 0; | |
1da177e4 LT |
654 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
655 | ||
656 | return ret; | |
657 | } | |
1da177e4 LT |
658 | EXPORT_SYMBOL(tty_register_ldisc); |
659 | ||
af9b897e AC |
660 | /** |
661 | * tty_unregister_ldisc - unload a line discipline | |
662 | * @disc: ldisc number | |
663 | * @new_ldisc: pointer to the ldisc object | |
664 | * | |
665 | * Remove a line discipline from the kernel providing it is not | |
666 | * currently in use. | |
667 | * | |
668 | * Locking: | |
669 | * takes tty_ldisc_lock to guard against ldisc races | |
670 | */ | |
671 | ||
bfb07599 AD |
672 | int tty_unregister_ldisc(int disc) |
673 | { | |
674 | unsigned long flags; | |
675 | int ret = 0; | |
676 | ||
677 | if (disc < N_TTY || disc >= NR_LDISCS) | |
678 | return -EINVAL; | |
679 | ||
680 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
681 | if (tty_ldiscs[disc].refcount) | |
682 | ret = -EBUSY; | |
683 | else | |
684 | tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; | |
685 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
686 | ||
687 | return ret; | |
688 | } | |
689 | EXPORT_SYMBOL(tty_unregister_ldisc); | |
690 | ||
af9b897e AC |
691 | /** |
692 | * tty_ldisc_get - take a reference to an ldisc | |
693 | * @disc: ldisc number | |
694 | * | |
695 | * Takes a reference to a line discipline. Deals with refcounts and | |
696 | * module locking counts. Returns NULL if the discipline is not available. | |
697 | * Returns a pointer to the discipline and bumps the ref count if it is | |
698 | * available | |
699 | * | |
700 | * Locking: | |
701 | * takes tty_ldisc_lock to guard against ldisc races | |
702 | */ | |
703 | ||
1da177e4 LT |
704 | struct tty_ldisc *tty_ldisc_get(int disc) |
705 | { | |
706 | unsigned long flags; | |
707 | struct tty_ldisc *ld; | |
708 | ||
709 | if (disc < N_TTY || disc >= NR_LDISCS) | |
710 | return NULL; | |
711 | ||
712 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
713 | ||
714 | ld = &tty_ldiscs[disc]; | |
715 | /* Check the entry is defined */ | |
716 | if(ld->flags & LDISC_FLAG_DEFINED) | |
717 | { | |
718 | /* If the module is being unloaded we can't use it */ | |
719 | if (!try_module_get(ld->owner)) | |
720 | ld = NULL; | |
721 | else /* lock it */ | |
722 | ld->refcount++; | |
723 | } | |
724 | else | |
725 | ld = NULL; | |
726 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
727 | return ld; | |
728 | } | |
729 | ||
730 | EXPORT_SYMBOL_GPL(tty_ldisc_get); | |
731 | ||
af9b897e AC |
732 | /** |
733 | * tty_ldisc_put - drop ldisc reference | |
734 | * @disc: ldisc number | |
735 | * | |
736 | * Drop a reference to a line discipline. Manage refcounts and | |
737 | * module usage counts | |
738 | * | |
739 | * Locking: | |
740 | * takes tty_ldisc_lock to guard against ldisc races | |
741 | */ | |
742 | ||
1da177e4 LT |
743 | void tty_ldisc_put(int disc) |
744 | { | |
745 | struct tty_ldisc *ld; | |
746 | unsigned long flags; | |
747 | ||
56ee4827 | 748 | BUG_ON(disc < N_TTY || disc >= NR_LDISCS); |
1da177e4 LT |
749 | |
750 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
751 | ld = &tty_ldiscs[disc]; | |
56ee4827 ES |
752 | BUG_ON(ld->refcount == 0); |
753 | ld->refcount--; | |
1da177e4 LT |
754 | module_put(ld->owner); |
755 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
756 | } | |
757 | ||
758 | EXPORT_SYMBOL_GPL(tty_ldisc_put); | |
759 | ||
af9b897e AC |
760 | /** |
761 | * tty_ldisc_assign - set ldisc on a tty | |
762 | * @tty: tty to assign | |
763 | * @ld: line discipline | |
764 | * | |
765 | * Install an instance of a line discipline into a tty structure. The | |
766 | * ldisc must have a reference count above zero to ensure it remains/ | |
767 | * The tty instance refcount starts at zero. | |
768 | * | |
769 | * Locking: | |
770 | * Caller must hold references | |
771 | */ | |
772 | ||
1da177e4 LT |
773 | static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) |
774 | { | |
775 | tty->ldisc = *ld; | |
776 | tty->ldisc.refcount = 0; | |
777 | } | |
778 | ||
779 | /** | |
780 | * tty_ldisc_try - internal helper | |
781 | * @tty: the tty | |
782 | * | |
783 | * Make a single attempt to grab and bump the refcount on | |
784 | * the tty ldisc. Return 0 on failure or 1 on success. This is | |
785 | * used to implement both the waiting and non waiting versions | |
786 | * of tty_ldisc_ref | |
af9b897e AC |
787 | * |
788 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
789 | */ |
790 | ||
791 | static int tty_ldisc_try(struct tty_struct *tty) | |
792 | { | |
793 | unsigned long flags; | |
794 | struct tty_ldisc *ld; | |
795 | int ret = 0; | |
796 | ||
797 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
798 | ld = &tty->ldisc; | |
799 | if(test_bit(TTY_LDISC, &tty->flags)) | |
800 | { | |
801 | ld->refcount++; | |
802 | ret = 1; | |
803 | } | |
804 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
805 | return ret; | |
806 | } | |
807 | ||
808 | /** | |
809 | * tty_ldisc_ref_wait - wait for the tty ldisc | |
810 | * @tty: tty device | |
811 | * | |
812 | * Dereference the line discipline for the terminal and take a | |
813 | * reference to it. If the line discipline is in flux then | |
814 | * wait patiently until it changes. | |
815 | * | |
816 | * Note: Must not be called from an IRQ/timer context. The caller | |
817 | * must also be careful not to hold other locks that will deadlock | |
818 | * against a discipline change, such as an existing ldisc reference | |
819 | * (which we check for) | |
af9b897e AC |
820 | * |
821 | * Locking: call functions take tty_ldisc_lock | |
1da177e4 LT |
822 | */ |
823 | ||
824 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) | |
825 | { | |
826 | /* wait_event is a macro */ | |
827 | wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); | |
828 | if(tty->ldisc.refcount == 0) | |
829 | printk(KERN_ERR "tty_ldisc_ref_wait\n"); | |
830 | return &tty->ldisc; | |
831 | } | |
832 | ||
833 | EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); | |
834 | ||
835 | /** | |
836 | * tty_ldisc_ref - get the tty ldisc | |
837 | * @tty: tty device | |
838 | * | |
839 | * Dereference the line discipline for the terminal and take a | |
840 | * reference to it. If the line discipline is in flux then | |
841 | * return NULL. Can be called from IRQ and timer functions. | |
af9b897e AC |
842 | * |
843 | * Locking: called functions take tty_ldisc_lock | |
1da177e4 LT |
844 | */ |
845 | ||
846 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) | |
847 | { | |
848 | if(tty_ldisc_try(tty)) | |
849 | return &tty->ldisc; | |
850 | return NULL; | |
851 | } | |
852 | ||
853 | EXPORT_SYMBOL_GPL(tty_ldisc_ref); | |
854 | ||
855 | /** | |
856 | * tty_ldisc_deref - free a tty ldisc reference | |
857 | * @ld: reference to free up | |
858 | * | |
859 | * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May | |
860 | * be called in IRQ context. | |
af9b897e AC |
861 | * |
862 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
863 | */ |
864 | ||
865 | void tty_ldisc_deref(struct tty_ldisc *ld) | |
866 | { | |
867 | unsigned long flags; | |
868 | ||
56ee4827 | 869 | BUG_ON(ld == NULL); |
1da177e4 LT |
870 | |
871 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
872 | if(ld->refcount == 0) | |
873 | printk(KERN_ERR "tty_ldisc_deref: no references.\n"); | |
874 | else | |
875 | ld->refcount--; | |
876 | if(ld->refcount == 0) | |
877 | wake_up(&tty_ldisc_wait); | |
878 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
879 | } | |
880 | ||
881 | EXPORT_SYMBOL_GPL(tty_ldisc_deref); | |
882 | ||
883 | /** | |
884 | * tty_ldisc_enable - allow ldisc use | |
885 | * @tty: terminal to activate ldisc on | |
886 | * | |
887 | * Set the TTY_LDISC flag when the line discipline can be called | |
888 | * again. Do neccessary wakeups for existing sleepers. | |
889 | * | |
890 | * Note: nobody should set this bit except via this function. Clearing | |
891 | * directly is allowed. | |
892 | */ | |
893 | ||
894 | static void tty_ldisc_enable(struct tty_struct *tty) | |
895 | { | |
896 | set_bit(TTY_LDISC, &tty->flags); | |
897 | wake_up(&tty_ldisc_wait); | |
898 | } | |
899 | ||
900 | /** | |
901 | * tty_set_ldisc - set line discipline | |
902 | * @tty: the terminal to set | |
903 | * @ldisc: the line discipline | |
904 | * | |
905 | * Set the discipline of a tty line. Must be called from a process | |
906 | * context. | |
af9b897e AC |
907 | * |
908 | * Locking: takes tty_ldisc_lock. | |
24ec839c | 909 | * called functions take termios_mutex |
1da177e4 LT |
910 | */ |
911 | ||
912 | static int tty_set_ldisc(struct tty_struct *tty, int ldisc) | |
913 | { | |
ff55fe20 JB |
914 | int retval = 0; |
915 | struct tty_ldisc o_ldisc; | |
1da177e4 LT |
916 | char buf[64]; |
917 | int work; | |
918 | unsigned long flags; | |
919 | struct tty_ldisc *ld; | |
ff55fe20 | 920 | struct tty_struct *o_tty; |
1da177e4 LT |
921 | |
922 | if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) | |
923 | return -EINVAL; | |
924 | ||
925 | restart: | |
926 | ||
1da177e4 LT |
927 | ld = tty_ldisc_get(ldisc); |
928 | /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ | |
929 | /* Cyrus Durgin <cider@speakeasy.org> */ | |
930 | if (ld == NULL) { | |
931 | request_module("tty-ldisc-%d", ldisc); | |
932 | ld = tty_ldisc_get(ldisc); | |
933 | } | |
934 | if (ld == NULL) | |
935 | return -EINVAL; | |
936 | ||
33f0f88f AC |
937 | /* |
938 | * No more input please, we are switching. The new ldisc | |
939 | * will update this value in the ldisc open function | |
940 | */ | |
941 | ||
942 | tty->receive_room = 0; | |
943 | ||
944 | /* | |
945 | * Problem: What do we do if this blocks ? | |
946 | */ | |
947 | ||
1da177e4 LT |
948 | tty_wait_until_sent(tty, 0); |
949 | ||
ff55fe20 JB |
950 | if (tty->ldisc.num == ldisc) { |
951 | tty_ldisc_put(ldisc); | |
952 | return 0; | |
953 | } | |
954 | ||
955 | o_ldisc = tty->ldisc; | |
956 | o_tty = tty->link; | |
957 | ||
1da177e4 LT |
958 | /* |
959 | * Make sure we don't change while someone holds a | |
960 | * reference to the line discipline. The TTY_LDISC bit | |
961 | * prevents anyone taking a reference once it is clear. | |
962 | * We need the lock to avoid racing reference takers. | |
963 | */ | |
ff55fe20 | 964 | |
1da177e4 | 965 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
ff55fe20 JB |
966 | if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { |
967 | if(tty->ldisc.refcount) { | |
968 | /* Free the new ldisc we grabbed. Must drop the lock | |
969 | first. */ | |
970 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
971 | tty_ldisc_put(ldisc); | |
972 | /* | |
973 | * There are several reasons we may be busy, including | |
974 | * random momentary I/O traffic. We must therefore | |
975 | * retry. We could distinguish between blocking ops | |
976 | * and retries if we made tty_ldisc_wait() smarter. That | |
977 | * is up for discussion. | |
978 | */ | |
979 | if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) | |
980 | return -ERESTARTSYS; | |
981 | goto restart; | |
982 | } | |
983 | if(o_tty && o_tty->ldisc.refcount) { | |
984 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
985 | tty_ldisc_put(ldisc); | |
986 | if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) | |
987 | return -ERESTARTSYS; | |
988 | goto restart; | |
989 | } | |
990 | } | |
991 | ||
992 | /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */ | |
993 | ||
994 | if (!test_bit(TTY_LDISC, &tty->flags)) { | |
1da177e4 LT |
995 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
996 | tty_ldisc_put(ldisc); | |
ff55fe20 JB |
997 | ld = tty_ldisc_ref_wait(tty); |
998 | tty_ldisc_deref(ld); | |
1da177e4 LT |
999 | goto restart; |
1000 | } | |
ff55fe20 JB |
1001 | |
1002 | clear_bit(TTY_LDISC, &tty->flags); | |
817d6d3b | 1003 | if (o_tty) |
ff55fe20 | 1004 | clear_bit(TTY_LDISC, &o_tty->flags); |
1da177e4 | 1005 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
ff55fe20 | 1006 | |
1da177e4 LT |
1007 | /* |
1008 | * From this point on we know nobody has an ldisc | |
1009 | * usage reference, nor can they obtain one until | |
1010 | * we say so later on. | |
1011 | */ | |
ff55fe20 | 1012 | |
33f0f88f | 1013 | work = cancel_delayed_work(&tty->buf.work); |
1da177e4 | 1014 | /* |
33f0f88f | 1015 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 LT |
1016 | */ |
1017 | ||
1018 | flush_scheduled_work(); | |
1019 | /* Shutdown the current discipline. */ | |
1020 | if (tty->ldisc.close) | |
1021 | (tty->ldisc.close)(tty); | |
1022 | ||
1023 | /* Now set up the new line discipline. */ | |
1024 | tty_ldisc_assign(tty, ld); | |
1025 | tty_set_termios_ldisc(tty, ldisc); | |
1026 | if (tty->ldisc.open) | |
1027 | retval = (tty->ldisc.open)(tty); | |
1028 | if (retval < 0) { | |
1029 | tty_ldisc_put(ldisc); | |
1030 | /* There is an outstanding reference here so this is safe */ | |
1031 | tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); | |
1032 | tty_set_termios_ldisc(tty, tty->ldisc.num); | |
1033 | if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { | |
1034 | tty_ldisc_put(o_ldisc.num); | |
1035 | /* This driver is always present */ | |
1036 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
1037 | tty_set_termios_ldisc(tty, N_TTY); | |
1038 | if (tty->ldisc.open) { | |
1039 | int r = tty->ldisc.open(tty); | |
1040 | ||
1041 | if (r < 0) | |
1042 | panic("Couldn't open N_TTY ldisc for " | |
1043 | "%s --- error %d.", | |
1044 | tty_name(tty, buf), r); | |
1045 | } | |
1046 | } | |
1047 | } | |
1048 | /* At this point we hold a reference to the new ldisc and a | |
1049 | a reference to the old ldisc. If we ended up flipping back | |
1050 | to the existing ldisc we have two references to it */ | |
1051 | ||
1052 | if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) | |
1053 | tty->driver->set_ldisc(tty); | |
1054 | ||
1055 | tty_ldisc_put(o_ldisc.num); | |
1056 | ||
1057 | /* | |
1058 | * Allow ldisc referencing to occur as soon as the driver | |
1059 | * ldisc callback completes. | |
1060 | */ | |
1061 | ||
1062 | tty_ldisc_enable(tty); | |
ff55fe20 JB |
1063 | if (o_tty) |
1064 | tty_ldisc_enable(o_tty); | |
1da177e4 LT |
1065 | |
1066 | /* Restart it in case no characters kick it off. Safe if | |
1067 | already running */ | |
ff55fe20 | 1068 | if (work) |
33f0f88f | 1069 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
1070 | return retval; |
1071 | } | |
1072 | ||
af9b897e AC |
1073 | /** |
1074 | * get_tty_driver - find device of a tty | |
1075 | * @dev_t: device identifier | |
1076 | * @index: returns the index of the tty | |
1077 | * | |
1078 | * This routine returns a tty driver structure, given a device number | |
1079 | * and also passes back the index number. | |
1080 | * | |
1081 | * Locking: caller must hold tty_mutex | |
1da177e4 | 1082 | */ |
af9b897e | 1083 | |
1da177e4 LT |
1084 | static struct tty_driver *get_tty_driver(dev_t device, int *index) |
1085 | { | |
1086 | struct tty_driver *p; | |
1087 | ||
1088 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1089 | dev_t base = MKDEV(p->major, p->minor_start); | |
1090 | if (device < base || device >= base + p->num) | |
1091 | continue; | |
1092 | *index = device - base; | |
1093 | return p; | |
1094 | } | |
1095 | return NULL; | |
1096 | } | |
1097 | ||
af9b897e AC |
1098 | /** |
1099 | * tty_check_change - check for POSIX terminal changes | |
1100 | * @tty: tty to check | |
1101 | * | |
1102 | * If we try to write to, or set the state of, a terminal and we're | |
1103 | * not in the foreground, send a SIGTTOU. If the signal is blocked or | |
1104 | * ignored, go ahead and perform the operation. (POSIX 7.2) | |
1105 | * | |
1106 | * Locking: none | |
1da177e4 | 1107 | */ |
af9b897e | 1108 | |
1da177e4 LT |
1109 | int tty_check_change(struct tty_struct * tty) |
1110 | { | |
1111 | if (current->signal->tty != tty) | |
1112 | return 0; | |
1113 | if (tty->pgrp <= 0) { | |
1114 | printk(KERN_WARNING "tty_check_change: tty->pgrp <= 0!\n"); | |
1115 | return 0; | |
1116 | } | |
1117 | if (process_group(current) == tty->pgrp) | |
1118 | return 0; | |
1119 | if (is_ignored(SIGTTOU)) | |
1120 | return 0; | |
1121 | if (is_orphaned_pgrp(process_group(current))) | |
1122 | return -EIO; | |
1123 | (void) kill_pg(process_group(current), SIGTTOU, 1); | |
1124 | return -ERESTARTSYS; | |
1125 | } | |
1126 | ||
1127 | EXPORT_SYMBOL(tty_check_change); | |
1128 | ||
1129 | static ssize_t hung_up_tty_read(struct file * file, char __user * buf, | |
1130 | size_t count, loff_t *ppos) | |
1131 | { | |
1132 | return 0; | |
1133 | } | |
1134 | ||
1135 | static ssize_t hung_up_tty_write(struct file * file, const char __user * buf, | |
1136 | size_t count, loff_t *ppos) | |
1137 | { | |
1138 | return -EIO; | |
1139 | } | |
1140 | ||
1141 | /* No kernel lock held - none needed ;) */ | |
1142 | static unsigned int hung_up_tty_poll(struct file * filp, poll_table * wait) | |
1143 | { | |
1144 | return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; | |
1145 | } | |
1146 | ||
1147 | static int hung_up_tty_ioctl(struct inode * inode, struct file * file, | |
1148 | unsigned int cmd, unsigned long arg) | |
1149 | { | |
1150 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1151 | } | |
1152 | ||
62322d25 | 1153 | static const struct file_operations tty_fops = { |
1da177e4 LT |
1154 | .llseek = no_llseek, |
1155 | .read = tty_read, | |
1156 | .write = tty_write, | |
1157 | .poll = tty_poll, | |
1158 | .ioctl = tty_ioctl, | |
1159 | .open = tty_open, | |
1160 | .release = tty_release, | |
1161 | .fasync = tty_fasync, | |
1162 | }; | |
1163 | ||
1164 | #ifdef CONFIG_UNIX98_PTYS | |
62322d25 | 1165 | static const struct file_operations ptmx_fops = { |
1da177e4 LT |
1166 | .llseek = no_llseek, |
1167 | .read = tty_read, | |
1168 | .write = tty_write, | |
1169 | .poll = tty_poll, | |
1170 | .ioctl = tty_ioctl, | |
1171 | .open = ptmx_open, | |
1172 | .release = tty_release, | |
1173 | .fasync = tty_fasync, | |
1174 | }; | |
1175 | #endif | |
1176 | ||
62322d25 | 1177 | static const struct file_operations console_fops = { |
1da177e4 LT |
1178 | .llseek = no_llseek, |
1179 | .read = tty_read, | |
1180 | .write = redirected_tty_write, | |
1181 | .poll = tty_poll, | |
1182 | .ioctl = tty_ioctl, | |
1183 | .open = tty_open, | |
1184 | .release = tty_release, | |
1185 | .fasync = tty_fasync, | |
1186 | }; | |
1187 | ||
62322d25 | 1188 | static const struct file_operations hung_up_tty_fops = { |
1da177e4 LT |
1189 | .llseek = no_llseek, |
1190 | .read = hung_up_tty_read, | |
1191 | .write = hung_up_tty_write, | |
1192 | .poll = hung_up_tty_poll, | |
1193 | .ioctl = hung_up_tty_ioctl, | |
1194 | .release = tty_release, | |
1195 | }; | |
1196 | ||
1197 | static DEFINE_SPINLOCK(redirect_lock); | |
1198 | static struct file *redirect; | |
1199 | ||
1200 | /** | |
1201 | * tty_wakeup - request more data | |
1202 | * @tty: terminal | |
1203 | * | |
1204 | * Internal and external helper for wakeups of tty. This function | |
1205 | * informs the line discipline if present that the driver is ready | |
1206 | * to receive more output data. | |
1207 | */ | |
1208 | ||
1209 | void tty_wakeup(struct tty_struct *tty) | |
1210 | { | |
1211 | struct tty_ldisc *ld; | |
1212 | ||
1213 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { | |
1214 | ld = tty_ldisc_ref(tty); | |
1215 | if(ld) { | |
1216 | if(ld->write_wakeup) | |
1217 | ld->write_wakeup(tty); | |
1218 | tty_ldisc_deref(ld); | |
1219 | } | |
1220 | } | |
1221 | wake_up_interruptible(&tty->write_wait); | |
1222 | } | |
1223 | ||
1224 | EXPORT_SYMBOL_GPL(tty_wakeup); | |
1225 | ||
1226 | /** | |
1227 | * tty_ldisc_flush - flush line discipline queue | |
1228 | * @tty: tty | |
1229 | * | |
1230 | * Flush the line discipline queue (if any) for this tty. If there | |
1231 | * is no line discipline active this is a no-op. | |
1232 | */ | |
1233 | ||
1234 | void tty_ldisc_flush(struct tty_struct *tty) | |
1235 | { | |
1236 | struct tty_ldisc *ld = tty_ldisc_ref(tty); | |
1237 | if(ld) { | |
1238 | if(ld->flush_buffer) | |
1239 | ld->flush_buffer(tty); | |
1240 | tty_ldisc_deref(ld); | |
1241 | } | |
1242 | } | |
1243 | ||
1244 | EXPORT_SYMBOL_GPL(tty_ldisc_flush); | |
edc6afc5 AC |
1245 | |
1246 | /** | |
1247 | * tty_reset_termios - reset terminal state | |
1248 | * @tty: tty to reset | |
1249 | * | |
1250 | * Restore a terminal to the driver default state | |
1251 | */ | |
1252 | ||
1253 | static void tty_reset_termios(struct tty_struct *tty) | |
1254 | { | |
1255 | mutex_lock(&tty->termios_mutex); | |
1256 | *tty->termios = tty->driver->init_termios; | |
1257 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
1258 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1259 | mutex_unlock(&tty->termios_mutex); | |
1260 | } | |
1da177e4 | 1261 | |
af9b897e AC |
1262 | /** |
1263 | * do_tty_hangup - actual handler for hangup events | |
65f27f38 | 1264 | * @work: tty device |
af9b897e AC |
1265 | * |
1266 | * This can be called by the "eventd" kernel thread. That is process | |
1267 | * synchronous but doesn't hold any locks, so we need to make sure we | |
1268 | * have the appropriate locks for what we're doing. | |
1269 | * | |
1270 | * The hangup event clears any pending redirections onto the hung up | |
1271 | * device. It ensures future writes will error and it does the needed | |
1272 | * line discipline hangup and signal delivery. The tty object itself | |
1273 | * remains intact. | |
1274 | * | |
1275 | * Locking: | |
1276 | * BKL | |
24ec839c PZ |
1277 | * redirect lock for undoing redirection |
1278 | * file list lock for manipulating list of ttys | |
1279 | * tty_ldisc_lock from called functions | |
1280 | * termios_mutex resetting termios data | |
1281 | * tasklist_lock to walk task list for hangup event | |
1282 | * ->siglock to protect ->signal/->sighand | |
1da177e4 | 1283 | */ |
65f27f38 | 1284 | static void do_tty_hangup(struct work_struct *work) |
1da177e4 | 1285 | { |
65f27f38 DH |
1286 | struct tty_struct *tty = |
1287 | container_of(work, struct tty_struct, hangup_work); | |
1da177e4 LT |
1288 | struct file * cons_filp = NULL; |
1289 | struct file *filp, *f = NULL; | |
1290 | struct task_struct *p; | |
1291 | struct tty_ldisc *ld; | |
1292 | int closecount = 0, n; | |
1293 | ||
1294 | if (!tty) | |
1295 | return; | |
1296 | ||
1297 | /* inuse_filps is protected by the single kernel lock */ | |
1298 | lock_kernel(); | |
1299 | ||
1300 | spin_lock(&redirect_lock); | |
1301 | if (redirect && redirect->private_data == tty) { | |
1302 | f = redirect; | |
1303 | redirect = NULL; | |
1304 | } | |
1305 | spin_unlock(&redirect_lock); | |
1306 | ||
1307 | check_tty_count(tty, "do_tty_hangup"); | |
1308 | file_list_lock(); | |
1309 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ | |
2f512016 | 1310 | list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { |
1da177e4 LT |
1311 | if (filp->f_op->write == redirected_tty_write) |
1312 | cons_filp = filp; | |
1313 | if (filp->f_op->write != tty_write) | |
1314 | continue; | |
1315 | closecount++; | |
1316 | tty_fasync(-1, filp, 0); /* can't block */ | |
1317 | filp->f_op = &hung_up_tty_fops; | |
1318 | } | |
1319 | file_list_unlock(); | |
1320 | ||
1321 | /* FIXME! What are the locking issues here? This may me overdoing things.. | |
1322 | * this question is especially important now that we've removed the irqlock. */ | |
1323 | ||
1324 | ld = tty_ldisc_ref(tty); | |
1325 | if(ld != NULL) /* We may have no line discipline at this point */ | |
1326 | { | |
1327 | if (ld->flush_buffer) | |
1328 | ld->flush_buffer(tty); | |
1329 | if (tty->driver->flush_buffer) | |
1330 | tty->driver->flush_buffer(tty); | |
1331 | if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && | |
1332 | ld->write_wakeup) | |
1333 | ld->write_wakeup(tty); | |
1334 | if (ld->hangup) | |
1335 | ld->hangup(tty); | |
1336 | } | |
1337 | ||
1338 | /* FIXME: Once we trust the LDISC code better we can wait here for | |
1339 | ldisc completion and fix the driver call race */ | |
1340 | ||
1341 | wake_up_interruptible(&tty->write_wait); | |
1342 | wake_up_interruptible(&tty->read_wait); | |
1343 | ||
1344 | /* | |
1345 | * Shutdown the current line discipline, and reset it to | |
1346 | * N_TTY. | |
1347 | */ | |
1348 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
edc6afc5 | 1349 | tty_reset_termios(tty); |
1da177e4 LT |
1350 | |
1351 | /* Defer ldisc switch */ | |
1352 | /* tty_deferred_ldisc_switch(N_TTY); | |
1353 | ||
1354 | This should get done automatically when the port closes and | |
1355 | tty_release is called */ | |
1356 | ||
1357 | read_lock(&tasklist_lock); | |
1358 | if (tty->session > 0) { | |
1359 | do_each_task_pid(tty->session, PIDTYPE_SID, p) { | |
24ec839c | 1360 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
1361 | if (p->signal->tty == tty) |
1362 | p->signal->tty = NULL; | |
24ec839c PZ |
1363 | if (!p->signal->leader) { |
1364 | spin_unlock_irq(&p->sighand->siglock); | |
1da177e4 | 1365 | continue; |
24ec839c PZ |
1366 | } |
1367 | __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); | |
1368 | __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); | |
1da177e4 LT |
1369 | if (tty->pgrp > 0) |
1370 | p->signal->tty_old_pgrp = tty->pgrp; | |
24ec839c | 1371 | spin_unlock_irq(&p->sighand->siglock); |
1da177e4 LT |
1372 | } while_each_task_pid(tty->session, PIDTYPE_SID, p); |
1373 | } | |
1374 | read_unlock(&tasklist_lock); | |
1375 | ||
1376 | tty->flags = 0; | |
1377 | tty->session = 0; | |
1378 | tty->pgrp = -1; | |
1379 | tty->ctrl_status = 0; | |
1380 | /* | |
1381 | * If one of the devices matches a console pointer, we | |
1382 | * cannot just call hangup() because that will cause | |
1383 | * tty->count and state->count to go out of sync. | |
1384 | * So we just call close() the right number of times. | |
1385 | */ | |
1386 | if (cons_filp) { | |
1387 | if (tty->driver->close) | |
1388 | for (n = 0; n < closecount; n++) | |
1389 | tty->driver->close(tty, cons_filp); | |
1390 | } else if (tty->driver->hangup) | |
1391 | (tty->driver->hangup)(tty); | |
1392 | ||
1393 | /* We don't want to have driver/ldisc interactions beyond | |
1394 | the ones we did here. The driver layer expects no | |
1395 | calls after ->hangup() from the ldisc side. However we | |
1396 | can't yet guarantee all that */ | |
1397 | ||
1398 | set_bit(TTY_HUPPED, &tty->flags); | |
1399 | if (ld) { | |
1400 | tty_ldisc_enable(tty); | |
1401 | tty_ldisc_deref(ld); | |
1402 | } | |
1403 | unlock_kernel(); | |
1404 | if (f) | |
1405 | fput(f); | |
1406 | } | |
1407 | ||
af9b897e AC |
1408 | /** |
1409 | * tty_hangup - trigger a hangup event | |
1410 | * @tty: tty to hangup | |
1411 | * | |
1412 | * A carrier loss (virtual or otherwise) has occurred on this like | |
1413 | * schedule a hangup sequence to run after this event. | |
1414 | */ | |
1415 | ||
1da177e4 LT |
1416 | void tty_hangup(struct tty_struct * tty) |
1417 | { | |
1418 | #ifdef TTY_DEBUG_HANGUP | |
1419 | char buf[64]; | |
1420 | ||
1421 | printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); | |
1422 | #endif | |
1423 | schedule_work(&tty->hangup_work); | |
1424 | } | |
1425 | ||
1426 | EXPORT_SYMBOL(tty_hangup); | |
1427 | ||
af9b897e AC |
1428 | /** |
1429 | * tty_vhangup - process vhangup | |
1430 | * @tty: tty to hangup | |
1431 | * | |
1432 | * The user has asked via system call for the terminal to be hung up. | |
1433 | * We do this synchronously so that when the syscall returns the process | |
1434 | * is complete. That guarantee is neccessary for security reasons. | |
1435 | */ | |
1436 | ||
1da177e4 LT |
1437 | void tty_vhangup(struct tty_struct * tty) |
1438 | { | |
1439 | #ifdef TTY_DEBUG_HANGUP | |
1440 | char buf[64]; | |
1441 | ||
1442 | printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); | |
1443 | #endif | |
65f27f38 | 1444 | do_tty_hangup(&tty->hangup_work); |
1da177e4 LT |
1445 | } |
1446 | EXPORT_SYMBOL(tty_vhangup); | |
1447 | ||
af9b897e AC |
1448 | /** |
1449 | * tty_hung_up_p - was tty hung up | |
1450 | * @filp: file pointer of tty | |
1451 | * | |
1452 | * Return true if the tty has been subject to a vhangup or a carrier | |
1453 | * loss | |
1454 | */ | |
1455 | ||
1da177e4 LT |
1456 | int tty_hung_up_p(struct file * filp) |
1457 | { | |
1458 | return (filp->f_op == &hung_up_tty_fops); | |
1459 | } | |
1460 | ||
1461 | EXPORT_SYMBOL(tty_hung_up_p); | |
1462 | ||
24ec839c PZ |
1463 | static void session_clear_tty(pid_t session) |
1464 | { | |
1465 | struct task_struct *p; | |
1466 | do_each_task_pid(session, PIDTYPE_SID, p) { | |
1467 | proc_clear_tty(p); | |
1468 | } while_each_task_pid(session, PIDTYPE_SID, p); | |
1469 | } | |
1470 | ||
af9b897e AC |
1471 | /** |
1472 | * disassociate_ctty - disconnect controlling tty | |
1473 | * @on_exit: true if exiting so need to "hang up" the session | |
1da177e4 | 1474 | * |
af9b897e AC |
1475 | * This function is typically called only by the session leader, when |
1476 | * it wants to disassociate itself from its controlling tty. | |
1477 | * | |
1478 | * It performs the following functions: | |
1da177e4 LT |
1479 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
1480 | * (2) Clears the tty from being controlling the session | |
1481 | * (3) Clears the controlling tty for all processes in the | |
1482 | * session group. | |
1483 | * | |
af9b897e AC |
1484 | * The argument on_exit is set to 1 if called when a process is |
1485 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. | |
1486 | * | |
24ec839c | 1487 | * Locking: |
af9b897e | 1488 | * BKL is taken for hysterical raisins |
24ec839c PZ |
1489 | * tty_mutex is taken to protect tty |
1490 | * ->siglock is taken to protect ->signal/->sighand | |
1491 | * tasklist_lock is taken to walk process list for sessions | |
1492 | * ->siglock is taken to protect ->signal/->sighand | |
1da177e4 | 1493 | */ |
af9b897e | 1494 | |
1da177e4 LT |
1495 | void disassociate_ctty(int on_exit) |
1496 | { | |
1497 | struct tty_struct *tty; | |
1da177e4 | 1498 | int tty_pgrp = -1; |
24ec839c | 1499 | int session; |
1da177e4 LT |
1500 | |
1501 | lock_kernel(); | |
1502 | ||
70522e12 | 1503 | mutex_lock(&tty_mutex); |
24ec839c | 1504 | tty = get_current_tty(); |
1da177e4 LT |
1505 | if (tty) { |
1506 | tty_pgrp = tty->pgrp; | |
70522e12 | 1507 | mutex_unlock(&tty_mutex); |
24ec839c | 1508 | /* XXX: here we race, there is nothing protecting tty */ |
1da177e4 LT |
1509 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
1510 | tty_vhangup(tty); | |
680a9671 EB |
1511 | } else if (on_exit) { |
1512 | pid_t old_pgrp; | |
1513 | spin_lock_irq(¤t->sighand->siglock); | |
1514 | old_pgrp = current->signal->tty_old_pgrp; | |
1515 | current->signal->tty_old_pgrp = 0; | |
1516 | spin_unlock_irq(¤t->sighand->siglock); | |
24ec839c PZ |
1517 | if (old_pgrp) { |
1518 | kill_pg(old_pgrp, SIGHUP, on_exit); | |
1519 | kill_pg(old_pgrp, SIGCONT, on_exit); | |
1da177e4 | 1520 | } |
70522e12 | 1521 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
1522 | unlock_kernel(); |
1523 | return; | |
1524 | } | |
1525 | if (tty_pgrp > 0) { | |
1526 | kill_pg(tty_pgrp, SIGHUP, on_exit); | |
1527 | if (!on_exit) | |
1528 | kill_pg(tty_pgrp, SIGCONT, on_exit); | |
1529 | } | |
1530 | ||
24ec839c | 1531 | spin_lock_irq(¤t->sighand->siglock); |
1da177e4 | 1532 | current->signal->tty_old_pgrp = 0; |
937949d9 | 1533 | session = process_session(current); |
24ec839c PZ |
1534 | spin_unlock_irq(¤t->sighand->siglock); |
1535 | ||
1536 | mutex_lock(&tty_mutex); | |
1537 | /* It is possible that do_tty_hangup has free'd this tty */ | |
1538 | tty = get_current_tty(); | |
1539 | if (tty) { | |
1540 | tty->session = 0; | |
1541 | tty->pgrp = 0; | |
1542 | } else { | |
1543 | #ifdef TTY_DEBUG_HANGUP | |
1544 | printk(KERN_DEBUG "error attempted to write to tty [0x%p]" | |
1545 | " = NULL", tty); | |
1546 | #endif | |
1547 | } | |
1548 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
1549 | |
1550 | /* Now clear signal->tty under the lock */ | |
1551 | read_lock(&tasklist_lock); | |
24ec839c | 1552 | session_clear_tty(session); |
1da177e4 | 1553 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1554 | unlock_kernel(); |
1555 | } | |
1556 | ||
af9b897e AC |
1557 | |
1558 | /** | |
1559 | * stop_tty - propogate flow control | |
1560 | * @tty: tty to stop | |
1561 | * | |
1562 | * Perform flow control to the driver. For PTY/TTY pairs we | |
1563 | * must also propogate the TIOCKPKT status. May be called | |
1564 | * on an already stopped device and will not re-call the driver | |
1565 | * method. | |
1566 | * | |
1567 | * This functionality is used by both the line disciplines for | |
1568 | * halting incoming flow and by the driver. It may therefore be | |
1569 | * called from any context, may be under the tty atomic_write_lock | |
1570 | * but not always. | |
1571 | * | |
1572 | * Locking: | |
1573 | * Broken. Relies on BKL which is unsafe here. | |
1574 | */ | |
1575 | ||
1da177e4 LT |
1576 | void stop_tty(struct tty_struct *tty) |
1577 | { | |
1578 | if (tty->stopped) | |
1579 | return; | |
1580 | tty->stopped = 1; | |
1581 | if (tty->link && tty->link->packet) { | |
1582 | tty->ctrl_status &= ~TIOCPKT_START; | |
1583 | tty->ctrl_status |= TIOCPKT_STOP; | |
1584 | wake_up_interruptible(&tty->link->read_wait); | |
1585 | } | |
1586 | if (tty->driver->stop) | |
1587 | (tty->driver->stop)(tty); | |
1588 | } | |
1589 | ||
1590 | EXPORT_SYMBOL(stop_tty); | |
1591 | ||
af9b897e AC |
1592 | /** |
1593 | * start_tty - propogate flow control | |
1594 | * @tty: tty to start | |
1595 | * | |
1596 | * Start a tty that has been stopped if at all possible. Perform | |
1597 | * any neccessary wakeups and propogate the TIOCPKT status. If this | |
1598 | * is the tty was previous stopped and is being started then the | |
1599 | * driver start method is invoked and the line discipline woken. | |
1600 | * | |
1601 | * Locking: | |
1602 | * Broken. Relies on BKL which is unsafe here. | |
1603 | */ | |
1604 | ||
1da177e4 LT |
1605 | void start_tty(struct tty_struct *tty) |
1606 | { | |
1607 | if (!tty->stopped || tty->flow_stopped) | |
1608 | return; | |
1609 | tty->stopped = 0; | |
1610 | if (tty->link && tty->link->packet) { | |
1611 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
1612 | tty->ctrl_status |= TIOCPKT_START; | |
1613 | wake_up_interruptible(&tty->link->read_wait); | |
1614 | } | |
1615 | if (tty->driver->start) | |
1616 | (tty->driver->start)(tty); | |
1617 | ||
1618 | /* If we have a running line discipline it may need kicking */ | |
1619 | tty_wakeup(tty); | |
1da177e4 LT |
1620 | } |
1621 | ||
1622 | EXPORT_SYMBOL(start_tty); | |
1623 | ||
af9b897e AC |
1624 | /** |
1625 | * tty_read - read method for tty device files | |
1626 | * @file: pointer to tty file | |
1627 | * @buf: user buffer | |
1628 | * @count: size of user buffer | |
1629 | * @ppos: unused | |
1630 | * | |
1631 | * Perform the read system call function on this terminal device. Checks | |
1632 | * for hung up devices before calling the line discipline method. | |
1633 | * | |
1634 | * Locking: | |
1635 | * Locks the line discipline internally while needed | |
1636 | * For historical reasons the line discipline read method is | |
1637 | * invoked under the BKL. This will go away in time so do not rely on it | |
1638 | * in new code. Multiple read calls may be outstanding in parallel. | |
1639 | */ | |
1640 | ||
1da177e4 LT |
1641 | static ssize_t tty_read(struct file * file, char __user * buf, size_t count, |
1642 | loff_t *ppos) | |
1643 | { | |
1644 | int i; | |
1645 | struct tty_struct * tty; | |
1646 | struct inode *inode; | |
1647 | struct tty_ldisc *ld; | |
1648 | ||
1649 | tty = (struct tty_struct *)file->private_data; | |
a7113a96 | 1650 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1651 | if (tty_paranoia_check(tty, inode, "tty_read")) |
1652 | return -EIO; | |
1653 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1654 | return -EIO; | |
1655 | ||
1656 | /* We want to wait for the line discipline to sort out in this | |
1657 | situation */ | |
1658 | ld = tty_ldisc_ref_wait(tty); | |
1659 | lock_kernel(); | |
1660 | if (ld->read) | |
1661 | i = (ld->read)(tty,file,buf,count); | |
1662 | else | |
1663 | i = -EIO; | |
1664 | tty_ldisc_deref(ld); | |
1665 | unlock_kernel(); | |
1666 | if (i > 0) | |
1667 | inode->i_atime = current_fs_time(inode->i_sb); | |
1668 | return i; | |
1669 | } | |
1670 | ||
1671 | /* | |
1672 | * Split writes up in sane blocksizes to avoid | |
1673 | * denial-of-service type attacks | |
1674 | */ | |
1675 | static inline ssize_t do_tty_write( | |
1676 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
1677 | struct tty_struct *tty, | |
1678 | struct file *file, | |
1679 | const char __user *buf, | |
1680 | size_t count) | |
1681 | { | |
1682 | ssize_t ret = 0, written = 0; | |
1683 | unsigned int chunk; | |
1684 | ||
af9b897e | 1685 | /* FIXME: O_NDELAY ... */ |
70522e12 | 1686 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) { |
1da177e4 LT |
1687 | return -ERESTARTSYS; |
1688 | } | |
1689 | ||
1690 | /* | |
1691 | * We chunk up writes into a temporary buffer. This | |
1692 | * simplifies low-level drivers immensely, since they | |
1693 | * don't have locking issues and user mode accesses. | |
1694 | * | |
1695 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
1696 | * big chunk-size.. | |
1697 | * | |
1698 | * The default chunk-size is 2kB, because the NTTY | |
1699 | * layer has problems with bigger chunks. It will | |
1700 | * claim to be able to handle more characters than | |
1701 | * it actually does. | |
af9b897e AC |
1702 | * |
1703 | * FIXME: This can probably go away now except that 64K chunks | |
1704 | * are too likely to fail unless switched to vmalloc... | |
1da177e4 LT |
1705 | */ |
1706 | chunk = 2048; | |
1707 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
1708 | chunk = 65536; | |
1709 | if (count < chunk) | |
1710 | chunk = count; | |
1711 | ||
70522e12 | 1712 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
1da177e4 LT |
1713 | if (tty->write_cnt < chunk) { |
1714 | unsigned char *buf; | |
1715 | ||
1716 | if (chunk < 1024) | |
1717 | chunk = 1024; | |
1718 | ||
1719 | buf = kmalloc(chunk, GFP_KERNEL); | |
1720 | if (!buf) { | |
70522e12 | 1721 | mutex_unlock(&tty->atomic_write_lock); |
1da177e4 LT |
1722 | return -ENOMEM; |
1723 | } | |
1724 | kfree(tty->write_buf); | |
1725 | tty->write_cnt = chunk; | |
1726 | tty->write_buf = buf; | |
1727 | } | |
1728 | ||
1729 | /* Do the write .. */ | |
1730 | for (;;) { | |
1731 | size_t size = count; | |
1732 | if (size > chunk) | |
1733 | size = chunk; | |
1734 | ret = -EFAULT; | |
1735 | if (copy_from_user(tty->write_buf, buf, size)) | |
1736 | break; | |
1737 | lock_kernel(); | |
1738 | ret = write(tty, file, tty->write_buf, size); | |
1739 | unlock_kernel(); | |
1740 | if (ret <= 0) | |
1741 | break; | |
1742 | written += ret; | |
1743 | buf += ret; | |
1744 | count -= ret; | |
1745 | if (!count) | |
1746 | break; | |
1747 | ret = -ERESTARTSYS; | |
1748 | if (signal_pending(current)) | |
1749 | break; | |
1750 | cond_resched(); | |
1751 | } | |
1752 | if (written) { | |
a7113a96 | 1753 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1754 | inode->i_mtime = current_fs_time(inode->i_sb); |
1755 | ret = written; | |
1756 | } | |
70522e12 | 1757 | mutex_unlock(&tty->atomic_write_lock); |
1da177e4 LT |
1758 | return ret; |
1759 | } | |
1760 | ||
1761 | ||
af9b897e AC |
1762 | /** |
1763 | * tty_write - write method for tty device file | |
1764 | * @file: tty file pointer | |
1765 | * @buf: user data to write | |
1766 | * @count: bytes to write | |
1767 | * @ppos: unused | |
1768 | * | |
1769 | * Write data to a tty device via the line discipline. | |
1770 | * | |
1771 | * Locking: | |
1772 | * Locks the line discipline as required | |
1773 | * Writes to the tty driver are serialized by the atomic_write_lock | |
1774 | * and are then processed in chunks to the device. The line discipline | |
1775 | * write method will not be involked in parallel for each device | |
1776 | * The line discipline write method is called under the big | |
1777 | * kernel lock for historical reasons. New code should not rely on this. | |
1778 | */ | |
1779 | ||
1da177e4 LT |
1780 | static ssize_t tty_write(struct file * file, const char __user * buf, size_t count, |
1781 | loff_t *ppos) | |
1782 | { | |
1783 | struct tty_struct * tty; | |
a7113a96 | 1784 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1785 | ssize_t ret; |
1786 | struct tty_ldisc *ld; | |
1787 | ||
1788 | tty = (struct tty_struct *)file->private_data; | |
1789 | if (tty_paranoia_check(tty, inode, "tty_write")) | |
1790 | return -EIO; | |
1791 | if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1792 | return -EIO; | |
1793 | ||
1794 | ld = tty_ldisc_ref_wait(tty); | |
1795 | if (!ld->write) | |
1796 | ret = -EIO; | |
1797 | else | |
1798 | ret = do_tty_write(ld->write, tty, file, buf, count); | |
1799 | tty_ldisc_deref(ld); | |
1800 | return ret; | |
1801 | } | |
1802 | ||
1803 | ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count, | |
1804 | loff_t *ppos) | |
1805 | { | |
1806 | struct file *p = NULL; | |
1807 | ||
1808 | spin_lock(&redirect_lock); | |
1809 | if (redirect) { | |
1810 | get_file(redirect); | |
1811 | p = redirect; | |
1812 | } | |
1813 | spin_unlock(&redirect_lock); | |
1814 | ||
1815 | if (p) { | |
1816 | ssize_t res; | |
1817 | res = vfs_write(p, buf, count, &p->f_pos); | |
1818 | fput(p); | |
1819 | return res; | |
1820 | } | |
1821 | ||
1822 | return tty_write(file, buf, count, ppos); | |
1823 | } | |
1824 | ||
1825 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
1826 | ||
af9b897e AC |
1827 | /** |
1828 | * pty_line_name - generate name for a pty | |
1829 | * @driver: the tty driver in use | |
1830 | * @index: the minor number | |
1831 | * @p: output buffer of at least 6 bytes | |
1832 | * | |
1833 | * Generate a name from a driver reference and write it to the output | |
1834 | * buffer. | |
1835 | * | |
1836 | * Locking: None | |
1837 | */ | |
1838 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1839 | { |
1840 | int i = index + driver->name_base; | |
1841 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
1842 | sprintf(p, "%s%c%x", | |
1843 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, | |
1844 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1845 | } | |
1846 | ||
af9b897e AC |
1847 | /** |
1848 | * pty_line_name - generate name for a tty | |
1849 | * @driver: the tty driver in use | |
1850 | * @index: the minor number | |
1851 | * @p: output buffer of at least 7 bytes | |
1852 | * | |
1853 | * Generate a name from a driver reference and write it to the output | |
1854 | * buffer. | |
1855 | * | |
1856 | * Locking: None | |
1857 | */ | |
1858 | static void tty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1859 | { |
1860 | sprintf(p, "%s%d", driver->name, index + driver->name_base); | |
1861 | } | |
1862 | ||
af9b897e AC |
1863 | /** |
1864 | * init_dev - initialise a tty device | |
1865 | * @driver: tty driver we are opening a device on | |
1866 | * @idx: device index | |
1867 | * @tty: returned tty structure | |
1868 | * | |
1869 | * Prepare a tty device. This may not be a "new" clean device but | |
1870 | * could also be an active device. The pty drivers require special | |
1871 | * handling because of this. | |
1872 | * | |
1873 | * Locking: | |
1874 | * The function is called under the tty_mutex, which | |
1875 | * protects us from the tty struct or driver itself going away. | |
1876 | * | |
1877 | * On exit the tty device has the line discipline attached and | |
1878 | * a reference count of 1. If a pair was created for pty/tty use | |
1879 | * and the other was a pty master then it too has a reference count of 1. | |
1880 | * | |
1da177e4 | 1881 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
70522e12 IM |
1882 | * failed open. The new code protects the open with a mutex, so it's |
1883 | * really quite straightforward. The mutex locking can probably be | |
1da177e4 LT |
1884 | * relaxed for the (most common) case of reopening a tty. |
1885 | */ | |
af9b897e | 1886 | |
1da177e4 LT |
1887 | static int init_dev(struct tty_driver *driver, int idx, |
1888 | struct tty_struct **ret_tty) | |
1889 | { | |
1890 | struct tty_struct *tty, *o_tty; | |
edc6afc5 AC |
1891 | struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; |
1892 | struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; | |
af9b897e | 1893 | int retval = 0; |
1da177e4 LT |
1894 | |
1895 | /* check whether we're reopening an existing tty */ | |
1896 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
1897 | tty = devpts_get_tty(idx); | |
1898 | if (tty && driver->subtype == PTY_TYPE_MASTER) | |
1899 | tty = tty->link; | |
1900 | } else { | |
1901 | tty = driver->ttys[idx]; | |
1902 | } | |
1903 | if (tty) goto fast_track; | |
1904 | ||
1905 | /* | |
1906 | * First time open is complex, especially for PTY devices. | |
1907 | * This code guarantees that either everything succeeds and the | |
1908 | * TTY is ready for operation, or else the table slots are vacated | |
1909 | * and the allocated memory released. (Except that the termios | |
1910 | * and locked termios may be retained.) | |
1911 | */ | |
1912 | ||
1913 | if (!try_module_get(driver->owner)) { | |
1914 | retval = -ENODEV; | |
1915 | goto end_init; | |
1916 | } | |
1917 | ||
1918 | o_tty = NULL; | |
1919 | tp = o_tp = NULL; | |
1920 | ltp = o_ltp = NULL; | |
1921 | ||
1922 | tty = alloc_tty_struct(); | |
1923 | if(!tty) | |
1924 | goto fail_no_mem; | |
1925 | initialize_tty_struct(tty); | |
1926 | tty->driver = driver; | |
1927 | tty->index = idx; | |
1928 | tty_line_name(driver, idx, tty->name); | |
1929 | ||
1930 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
1931 | tp_loc = &tty->termios; | |
1932 | ltp_loc = &tty->termios_locked; | |
1933 | } else { | |
1934 | tp_loc = &driver->termios[idx]; | |
1935 | ltp_loc = &driver->termios_locked[idx]; | |
1936 | } | |
1937 | ||
1938 | if (!*tp_loc) { | |
edc6afc5 | 1939 | tp = (struct ktermios *) kmalloc(sizeof(struct ktermios), |
1da177e4 LT |
1940 | GFP_KERNEL); |
1941 | if (!tp) | |
1942 | goto free_mem_out; | |
1943 | *tp = driver->init_termios; | |
1944 | } | |
1945 | ||
1946 | if (!*ltp_loc) { | |
edc6afc5 | 1947 | ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios), |
1da177e4 LT |
1948 | GFP_KERNEL); |
1949 | if (!ltp) | |
1950 | goto free_mem_out; | |
edc6afc5 | 1951 | memset(ltp, 0, sizeof(struct ktermios)); |
1da177e4 LT |
1952 | } |
1953 | ||
1954 | if (driver->type == TTY_DRIVER_TYPE_PTY) { | |
1955 | o_tty = alloc_tty_struct(); | |
1956 | if (!o_tty) | |
1957 | goto free_mem_out; | |
1958 | initialize_tty_struct(o_tty); | |
1959 | o_tty->driver = driver->other; | |
1960 | o_tty->index = idx; | |
1961 | tty_line_name(driver->other, idx, o_tty->name); | |
1962 | ||
1963 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
1964 | o_tp_loc = &o_tty->termios; | |
1965 | o_ltp_loc = &o_tty->termios_locked; | |
1966 | } else { | |
1967 | o_tp_loc = &driver->other->termios[idx]; | |
1968 | o_ltp_loc = &driver->other->termios_locked[idx]; | |
1969 | } | |
1970 | ||
1971 | if (!*o_tp_loc) { | |
edc6afc5 AC |
1972 | o_tp = (struct ktermios *) |
1973 | kmalloc(sizeof(struct ktermios), GFP_KERNEL); | |
1da177e4 LT |
1974 | if (!o_tp) |
1975 | goto free_mem_out; | |
1976 | *o_tp = driver->other->init_termios; | |
1977 | } | |
1978 | ||
1979 | if (!*o_ltp_loc) { | |
edc6afc5 AC |
1980 | o_ltp = (struct ktermios *) |
1981 | kmalloc(sizeof(struct ktermios), GFP_KERNEL); | |
1da177e4 LT |
1982 | if (!o_ltp) |
1983 | goto free_mem_out; | |
edc6afc5 | 1984 | memset(o_ltp, 0, sizeof(struct ktermios)); |
1da177e4 LT |
1985 | } |
1986 | ||
1987 | /* | |
1988 | * Everything allocated ... set up the o_tty structure. | |
1989 | */ | |
1990 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
1991 | driver->other->ttys[idx] = o_tty; | |
1992 | } | |
1993 | if (!*o_tp_loc) | |
1994 | *o_tp_loc = o_tp; | |
1995 | if (!*o_ltp_loc) | |
1996 | *o_ltp_loc = o_ltp; | |
1997 | o_tty->termios = *o_tp_loc; | |
1998 | o_tty->termios_locked = *o_ltp_loc; | |
1999 | driver->other->refcount++; | |
2000 | if (driver->subtype == PTY_TYPE_MASTER) | |
2001 | o_tty->count++; | |
2002 | ||
2003 | /* Establish the links in both directions */ | |
2004 | tty->link = o_tty; | |
2005 | o_tty->link = tty; | |
2006 | } | |
2007 | ||
2008 | /* | |
2009 | * All structures have been allocated, so now we install them. | |
d5698c28 | 2010 | * Failures after this point use release_tty to clean up, so |
1da177e4 LT |
2011 | * there's no need to null out the local pointers. |
2012 | */ | |
2013 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2014 | driver->ttys[idx] = tty; | |
2015 | } | |
2016 | ||
2017 | if (!*tp_loc) | |
2018 | *tp_loc = tp; | |
2019 | if (!*ltp_loc) | |
2020 | *ltp_loc = ltp; | |
2021 | tty->termios = *tp_loc; | |
2022 | tty->termios_locked = *ltp_loc; | |
edc6afc5 AC |
2023 | /* Compatibility until drivers always set this */ |
2024 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
2025 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1da177e4 LT |
2026 | driver->refcount++; |
2027 | tty->count++; | |
2028 | ||
2029 | /* | |
2030 | * Structures all installed ... call the ldisc open routines. | |
d5698c28 CH |
2031 | * If we fail here just call release_tty to clean up. No need |
2032 | * to decrement the use counts, as release_tty doesn't care. | |
1da177e4 LT |
2033 | */ |
2034 | ||
2035 | if (tty->ldisc.open) { | |
2036 | retval = (tty->ldisc.open)(tty); | |
2037 | if (retval) | |
2038 | goto release_mem_out; | |
2039 | } | |
2040 | if (o_tty && o_tty->ldisc.open) { | |
2041 | retval = (o_tty->ldisc.open)(o_tty); | |
2042 | if (retval) { | |
2043 | if (tty->ldisc.close) | |
2044 | (tty->ldisc.close)(tty); | |
2045 | goto release_mem_out; | |
2046 | } | |
2047 | tty_ldisc_enable(o_tty); | |
2048 | } | |
2049 | tty_ldisc_enable(tty); | |
2050 | goto success; | |
2051 | ||
2052 | /* | |
2053 | * This fast open can be used if the tty is already open. | |
2054 | * No memory is allocated, and the only failures are from | |
2055 | * attempting to open a closing tty or attempting multiple | |
2056 | * opens on a pty master. | |
2057 | */ | |
2058 | fast_track: | |
2059 | if (test_bit(TTY_CLOSING, &tty->flags)) { | |
2060 | retval = -EIO; | |
2061 | goto end_init; | |
2062 | } | |
2063 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
2064 | driver->subtype == PTY_TYPE_MASTER) { | |
2065 | /* | |
2066 | * special case for PTY masters: only one open permitted, | |
2067 | * and the slave side open count is incremented as well. | |
2068 | */ | |
2069 | if (tty->count) { | |
2070 | retval = -EIO; | |
2071 | goto end_init; | |
2072 | } | |
2073 | tty->link->count++; | |
2074 | } | |
2075 | tty->count++; | |
2076 | tty->driver = driver; /* N.B. why do this every time?? */ | |
2077 | ||
2078 | /* FIXME */ | |
2079 | if(!test_bit(TTY_LDISC, &tty->flags)) | |
2080 | printk(KERN_ERR "init_dev but no ldisc\n"); | |
2081 | success: | |
2082 | *ret_tty = tty; | |
2083 | ||
70522e12 | 2084 | /* All paths come through here to release the mutex */ |
1da177e4 LT |
2085 | end_init: |
2086 | return retval; | |
2087 | ||
2088 | /* Release locally allocated memory ... nothing placed in slots */ | |
2089 | free_mem_out: | |
735d5661 | 2090 | kfree(o_tp); |
1da177e4 LT |
2091 | if (o_tty) |
2092 | free_tty_struct(o_tty); | |
735d5661 JJ |
2093 | kfree(ltp); |
2094 | kfree(tp); | |
1da177e4 LT |
2095 | free_tty_struct(tty); |
2096 | ||
2097 | fail_no_mem: | |
2098 | module_put(driver->owner); | |
2099 | retval = -ENOMEM; | |
2100 | goto end_init; | |
2101 | ||
d5698c28 | 2102 | /* call the tty release_tty routine to clean out this slot */ |
1da177e4 | 2103 | release_mem_out: |
4050914f AM |
2104 | if (printk_ratelimit()) |
2105 | printk(KERN_INFO "init_dev: ldisc open failed, " | |
2106 | "clearing slot %d\n", idx); | |
d5698c28 | 2107 | release_tty(tty, idx); |
1da177e4 LT |
2108 | goto end_init; |
2109 | } | |
2110 | ||
af9b897e | 2111 | /** |
d5698c28 | 2112 | * release_one_tty - release tty structure memory |
af9b897e AC |
2113 | * |
2114 | * Releases memory associated with a tty structure, and clears out the | |
2115 | * driver table slots. This function is called when a device is no longer | |
2116 | * in use. It also gets called when setup of a device fails. | |
2117 | * | |
2118 | * Locking: | |
2119 | * tty_mutex - sometimes only | |
2120 | * takes the file list lock internally when working on the list | |
2121 | * of ttys that the driver keeps. | |
2122 | * FIXME: should we require tty_mutex is held here ?? | |
1da177e4 | 2123 | */ |
d5698c28 | 2124 | static void release_one_tty(struct tty_struct *tty, int idx) |
1da177e4 | 2125 | { |
1da177e4 | 2126 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
d5698c28 | 2127 | struct ktermios *tp; |
1da177e4 LT |
2128 | |
2129 | if (!devpts) | |
2130 | tty->driver->ttys[idx] = NULL; | |
d5698c28 | 2131 | |
1da177e4 LT |
2132 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
2133 | tp = tty->termios; | |
2134 | if (!devpts) | |
2135 | tty->driver->termios[idx] = NULL; | |
2136 | kfree(tp); | |
2137 | ||
2138 | tp = tty->termios_locked; | |
2139 | if (!devpts) | |
2140 | tty->driver->termios_locked[idx] = NULL; | |
2141 | kfree(tp); | |
2142 | } | |
2143 | ||
d5698c28 | 2144 | |
1da177e4 LT |
2145 | tty->magic = 0; |
2146 | tty->driver->refcount--; | |
d5698c28 | 2147 | |
1da177e4 LT |
2148 | file_list_lock(); |
2149 | list_del_init(&tty->tty_files); | |
2150 | file_list_unlock(); | |
d5698c28 | 2151 | |
1da177e4 LT |
2152 | free_tty_struct(tty); |
2153 | } | |
2154 | ||
d5698c28 CH |
2155 | /** |
2156 | * release_tty - release tty structure memory | |
2157 | * | |
2158 | * Release both @tty and a possible linked partner (think pty pair), | |
2159 | * and decrement the refcount of the backing module. | |
2160 | * | |
2161 | * Locking: | |
2162 | * tty_mutex - sometimes only | |
2163 | * takes the file list lock internally when working on the list | |
2164 | * of ttys that the driver keeps. | |
2165 | * FIXME: should we require tty_mutex is held here ?? | |
2166 | */ | |
2167 | static void release_tty(struct tty_struct *tty, int idx) | |
2168 | { | |
2169 | struct tty_driver *driver = tty->driver; | |
2170 | ||
2171 | if (tty->link) | |
2172 | release_one_tty(tty->link, idx); | |
2173 | release_one_tty(tty, idx); | |
2174 | module_put(driver->owner); | |
2175 | } | |
2176 | ||
1da177e4 LT |
2177 | /* |
2178 | * Even releasing the tty structures is a tricky business.. We have | |
2179 | * to be very careful that the structures are all released at the | |
2180 | * same time, as interrupts might otherwise get the wrong pointers. | |
2181 | * | |
2182 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
2183 | * lead to double frees or releasing memory still in use. | |
2184 | */ | |
2185 | static void release_dev(struct file * filp) | |
2186 | { | |
2187 | struct tty_struct *tty, *o_tty; | |
2188 | int pty_master, tty_closing, o_tty_closing, do_sleep; | |
14a6283e | 2189 | int devpts; |
1da177e4 LT |
2190 | int idx; |
2191 | char buf[64]; | |
2192 | unsigned long flags; | |
2193 | ||
2194 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2195 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "release_dev")) |
1da177e4 LT |
2196 | return; |
2197 | ||
2198 | check_tty_count(tty, "release_dev"); | |
2199 | ||
2200 | tty_fasync(-1, filp, 0); | |
2201 | ||
2202 | idx = tty->index; | |
2203 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2204 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2205 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; | |
1da177e4 LT |
2206 | o_tty = tty->link; |
2207 | ||
2208 | #ifdef TTY_PARANOIA_CHECK | |
2209 | if (idx < 0 || idx >= tty->driver->num) { | |
2210 | printk(KERN_DEBUG "release_dev: bad idx when trying to " | |
2211 | "free (%s)\n", tty->name); | |
2212 | return; | |
2213 | } | |
2214 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2215 | if (tty != tty->driver->ttys[idx]) { | |
2216 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " | |
2217 | "for (%s)\n", idx, tty->name); | |
2218 | return; | |
2219 | } | |
2220 | if (tty->termios != tty->driver->termios[idx]) { | |
2221 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " | |
2222 | "for (%s)\n", | |
2223 | idx, tty->name); | |
2224 | return; | |
2225 | } | |
2226 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { | |
2227 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " | |
2228 | "termios_locked for (%s)\n", | |
2229 | idx, tty->name); | |
2230 | return; | |
2231 | } | |
2232 | } | |
2233 | #endif | |
2234 | ||
2235 | #ifdef TTY_DEBUG_HANGUP | |
2236 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", | |
2237 | tty_name(tty, buf), tty->count); | |
2238 | #endif | |
2239 | ||
2240 | #ifdef TTY_PARANOIA_CHECK | |
2241 | if (tty->driver->other && | |
2242 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2243 | if (o_tty != tty->driver->other->ttys[idx]) { | |
2244 | printk(KERN_DEBUG "release_dev: other->table[%d] " | |
2245 | "not o_tty for (%s)\n", | |
2246 | idx, tty->name); | |
2247 | return; | |
2248 | } | |
2249 | if (o_tty->termios != tty->driver->other->termios[idx]) { | |
2250 | printk(KERN_DEBUG "release_dev: other->termios[%d] " | |
2251 | "not o_termios for (%s)\n", | |
2252 | idx, tty->name); | |
2253 | return; | |
2254 | } | |
2255 | if (o_tty->termios_locked != | |
2256 | tty->driver->other->termios_locked[idx]) { | |
2257 | printk(KERN_DEBUG "release_dev: other->termios_locked[" | |
2258 | "%d] not o_termios_locked for (%s)\n", | |
2259 | idx, tty->name); | |
2260 | return; | |
2261 | } | |
2262 | if (o_tty->link != tty) { | |
2263 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); | |
2264 | return; | |
2265 | } | |
2266 | } | |
2267 | #endif | |
2268 | if (tty->driver->close) | |
2269 | tty->driver->close(tty, filp); | |
2270 | ||
2271 | /* | |
2272 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
2273 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
2274 | * wait queues and kick everyone out _before_ actually starting to | |
2275 | * close. This ensures that we won't block while releasing the tty | |
2276 | * structure. | |
2277 | * | |
2278 | * The test for the o_tty closing is necessary, since the master and | |
2279 | * slave sides may close in any order. If the slave side closes out | |
2280 | * first, its count will be one, since the master side holds an open. | |
2281 | * Thus this test wouldn't be triggered at the time the slave closes, | |
2282 | * so we do it now. | |
2283 | * | |
2284 | * Note that it's possible for the tty to be opened again while we're | |
2285 | * flushing out waiters. By recalculating the closing flags before | |
2286 | * each iteration we avoid any problems. | |
2287 | */ | |
2288 | while (1) { | |
2289 | /* Guard against races with tty->count changes elsewhere and | |
2290 | opens on /dev/tty */ | |
2291 | ||
70522e12 | 2292 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2293 | tty_closing = tty->count <= 1; |
2294 | o_tty_closing = o_tty && | |
2295 | (o_tty->count <= (pty_master ? 1 : 0)); | |
1da177e4 LT |
2296 | do_sleep = 0; |
2297 | ||
2298 | if (tty_closing) { | |
2299 | if (waitqueue_active(&tty->read_wait)) { | |
2300 | wake_up(&tty->read_wait); | |
2301 | do_sleep++; | |
2302 | } | |
2303 | if (waitqueue_active(&tty->write_wait)) { | |
2304 | wake_up(&tty->write_wait); | |
2305 | do_sleep++; | |
2306 | } | |
2307 | } | |
2308 | if (o_tty_closing) { | |
2309 | if (waitqueue_active(&o_tty->read_wait)) { | |
2310 | wake_up(&o_tty->read_wait); | |
2311 | do_sleep++; | |
2312 | } | |
2313 | if (waitqueue_active(&o_tty->write_wait)) { | |
2314 | wake_up(&o_tty->write_wait); | |
2315 | do_sleep++; | |
2316 | } | |
2317 | } | |
2318 | if (!do_sleep) | |
2319 | break; | |
2320 | ||
2321 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " | |
2322 | "active!\n", tty_name(tty, buf)); | |
70522e12 | 2323 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2324 | schedule(); |
2325 | } | |
2326 | ||
2327 | /* | |
2328 | * The closing flags are now consistent with the open counts on | |
2329 | * both sides, and we've completed the last operation that could | |
2330 | * block, so it's safe to proceed with closing. | |
2331 | */ | |
1da177e4 LT |
2332 | if (pty_master) { |
2333 | if (--o_tty->count < 0) { | |
2334 | printk(KERN_WARNING "release_dev: bad pty slave count " | |
2335 | "(%d) for %s\n", | |
2336 | o_tty->count, tty_name(o_tty, buf)); | |
2337 | o_tty->count = 0; | |
2338 | } | |
2339 | } | |
2340 | if (--tty->count < 0) { | |
2341 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", | |
2342 | tty->count, tty_name(tty, buf)); | |
2343 | tty->count = 0; | |
2344 | } | |
1da177e4 LT |
2345 | |
2346 | /* | |
2347 | * We've decremented tty->count, so we need to remove this file | |
2348 | * descriptor off the tty->tty_files list; this serves two | |
2349 | * purposes: | |
2350 | * - check_tty_count sees the correct number of file descriptors | |
2351 | * associated with this tty. | |
2352 | * - do_tty_hangup no longer sees this file descriptor as | |
2353 | * something that needs to be handled for hangups. | |
2354 | */ | |
2355 | file_kill(filp); | |
2356 | filp->private_data = NULL; | |
2357 | ||
2358 | /* | |
2359 | * Perform some housekeeping before deciding whether to return. | |
2360 | * | |
2361 | * Set the TTY_CLOSING flag if this was the last open. In the | |
2362 | * case of a pty we may have to wait around for the other side | |
2363 | * to close, and TTY_CLOSING makes sure we can't be reopened. | |
2364 | */ | |
2365 | if(tty_closing) | |
2366 | set_bit(TTY_CLOSING, &tty->flags); | |
2367 | if(o_tty_closing) | |
2368 | set_bit(TTY_CLOSING, &o_tty->flags); | |
2369 | ||
2370 | /* | |
2371 | * If _either_ side is closing, make sure there aren't any | |
2372 | * processes that still think tty or o_tty is their controlling | |
2373 | * tty. | |
2374 | */ | |
2375 | if (tty_closing || o_tty_closing) { | |
1da177e4 | 2376 | read_lock(&tasklist_lock); |
24ec839c | 2377 | session_clear_tty(tty->session); |
1da177e4 | 2378 | if (o_tty) |
24ec839c | 2379 | session_clear_tty(o_tty->session); |
1da177e4 LT |
2380 | read_unlock(&tasklist_lock); |
2381 | } | |
2382 | ||
70522e12 | 2383 | mutex_unlock(&tty_mutex); |
da965822 | 2384 | |
1da177e4 LT |
2385 | /* check whether both sides are closing ... */ |
2386 | if (!tty_closing || (o_tty && !o_tty_closing)) | |
2387 | return; | |
2388 | ||
2389 | #ifdef TTY_DEBUG_HANGUP | |
2390 | printk(KERN_DEBUG "freeing tty structure..."); | |
2391 | #endif | |
2392 | /* | |
2393 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then | |
2394 | * kill any delayed work. As this is the final close it does not | |
2395 | * race with the set_ldisc code path. | |
2396 | */ | |
2397 | clear_bit(TTY_LDISC, &tty->flags); | |
33f0f88f | 2398 | cancel_delayed_work(&tty->buf.work); |
1da177e4 LT |
2399 | |
2400 | /* | |
33f0f88f | 2401 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 LT |
2402 | */ |
2403 | ||
2404 | flush_scheduled_work(); | |
2405 | ||
2406 | /* | |
2407 | * Wait for any short term users (we know they are just driver | |
2408 | * side waiters as the file is closing so user count on the file | |
2409 | * side is zero. | |
2410 | */ | |
2411 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2412 | while(tty->ldisc.refcount) | |
2413 | { | |
2414 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2415 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); | |
2416 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2417 | } | |
2418 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2419 | /* | |
2420 | * Shutdown the current line discipline, and reset it to N_TTY. | |
2421 | * N.B. why reset ldisc when we're releasing the memory?? | |
2422 | * | |
2423 | * FIXME: this MUST get fixed for the new reflocking | |
2424 | */ | |
2425 | if (tty->ldisc.close) | |
2426 | (tty->ldisc.close)(tty); | |
2427 | tty_ldisc_put(tty->ldisc.num); | |
2428 | ||
2429 | /* | |
2430 | * Switch the line discipline back | |
2431 | */ | |
2432 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
2433 | tty_set_termios_ldisc(tty,N_TTY); | |
2434 | if (o_tty) { | |
2435 | /* FIXME: could o_tty be in setldisc here ? */ | |
2436 | clear_bit(TTY_LDISC, &o_tty->flags); | |
2437 | if (o_tty->ldisc.close) | |
2438 | (o_tty->ldisc.close)(o_tty); | |
2439 | tty_ldisc_put(o_tty->ldisc.num); | |
2440 | tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); | |
2441 | tty_set_termios_ldisc(o_tty,N_TTY); | |
2442 | } | |
2443 | /* | |
d5698c28 | 2444 | * The release_tty function takes care of the details of clearing |
1da177e4 LT |
2445 | * the slots and preserving the termios structure. |
2446 | */ | |
d5698c28 | 2447 | release_tty(tty, idx); |
1da177e4 LT |
2448 | |
2449 | #ifdef CONFIG_UNIX98_PTYS | |
2450 | /* Make this pty number available for reallocation */ | |
2451 | if (devpts) { | |
2452 | down(&allocated_ptys_lock); | |
2453 | idr_remove(&allocated_ptys, idx); | |
2454 | up(&allocated_ptys_lock); | |
2455 | } | |
2456 | #endif | |
2457 | ||
2458 | } | |
2459 | ||
af9b897e AC |
2460 | /** |
2461 | * tty_open - open a tty device | |
2462 | * @inode: inode of device file | |
2463 | * @filp: file pointer to tty | |
1da177e4 | 2464 | * |
af9b897e AC |
2465 | * tty_open and tty_release keep up the tty count that contains the |
2466 | * number of opens done on a tty. We cannot use the inode-count, as | |
2467 | * different inodes might point to the same tty. | |
1da177e4 | 2468 | * |
af9b897e AC |
2469 | * Open-counting is needed for pty masters, as well as for keeping |
2470 | * track of serial lines: DTR is dropped when the last close happens. | |
2471 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
2472 | * | |
2473 | * The termios state of a pty is reset on first open so that | |
2474 | * settings don't persist across reuse. | |
2475 | * | |
24ec839c PZ |
2476 | * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. |
2477 | * tty->count should protect the rest. | |
2478 | * ->siglock protects ->signal/->sighand | |
1da177e4 | 2479 | */ |
af9b897e | 2480 | |
1da177e4 LT |
2481 | static int tty_open(struct inode * inode, struct file * filp) |
2482 | { | |
2483 | struct tty_struct *tty; | |
2484 | int noctty, retval; | |
2485 | struct tty_driver *driver; | |
2486 | int index; | |
2487 | dev_t device = inode->i_rdev; | |
2488 | unsigned short saved_flags = filp->f_flags; | |
2489 | ||
2490 | nonseekable_open(inode, filp); | |
2491 | ||
2492 | retry_open: | |
2493 | noctty = filp->f_flags & O_NOCTTY; | |
2494 | index = -1; | |
2495 | retval = 0; | |
2496 | ||
70522e12 | 2497 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2498 | |
2499 | if (device == MKDEV(TTYAUX_MAJOR,0)) { | |
24ec839c PZ |
2500 | tty = get_current_tty(); |
2501 | if (!tty) { | |
70522e12 | 2502 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2503 | return -ENXIO; |
2504 | } | |
24ec839c PZ |
2505 | driver = tty->driver; |
2506 | index = tty->index; | |
1da177e4 LT |
2507 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
2508 | /* noctty = 1; */ | |
2509 | goto got_driver; | |
2510 | } | |
2511 | #ifdef CONFIG_VT | |
2512 | if (device == MKDEV(TTY_MAJOR,0)) { | |
2513 | extern struct tty_driver *console_driver; | |
2514 | driver = console_driver; | |
2515 | index = fg_console; | |
2516 | noctty = 1; | |
2517 | goto got_driver; | |
2518 | } | |
2519 | #endif | |
2520 | if (device == MKDEV(TTYAUX_MAJOR,1)) { | |
2521 | driver = console_device(&index); | |
2522 | if (driver) { | |
2523 | /* Don't let /dev/console block */ | |
2524 | filp->f_flags |= O_NONBLOCK; | |
2525 | noctty = 1; | |
2526 | goto got_driver; | |
2527 | } | |
70522e12 | 2528 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2529 | return -ENODEV; |
2530 | } | |
2531 | ||
2532 | driver = get_tty_driver(device, &index); | |
2533 | if (!driver) { | |
70522e12 | 2534 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2535 | return -ENODEV; |
2536 | } | |
2537 | got_driver: | |
2538 | retval = init_dev(driver, index, &tty); | |
70522e12 | 2539 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2540 | if (retval) |
2541 | return retval; | |
2542 | ||
2543 | filp->private_data = tty; | |
2544 | file_move(filp, &tty->tty_files); | |
2545 | check_tty_count(tty, "tty_open"); | |
2546 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2547 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2548 | noctty = 1; | |
2549 | #ifdef TTY_DEBUG_HANGUP | |
2550 | printk(KERN_DEBUG "opening %s...", tty->name); | |
2551 | #endif | |
2552 | if (!retval) { | |
2553 | if (tty->driver->open) | |
2554 | retval = tty->driver->open(tty, filp); | |
2555 | else | |
2556 | retval = -ENODEV; | |
2557 | } | |
2558 | filp->f_flags = saved_flags; | |
2559 | ||
2560 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) | |
2561 | retval = -EBUSY; | |
2562 | ||
2563 | if (retval) { | |
2564 | #ifdef TTY_DEBUG_HANGUP | |
2565 | printk(KERN_DEBUG "error %d in opening %s...", retval, | |
2566 | tty->name); | |
2567 | #endif | |
2568 | release_dev(filp); | |
2569 | if (retval != -ERESTARTSYS) | |
2570 | return retval; | |
2571 | if (signal_pending(current)) | |
2572 | return retval; | |
2573 | schedule(); | |
2574 | /* | |
2575 | * Need to reset f_op in case a hangup happened. | |
2576 | */ | |
2577 | if (filp->f_op == &hung_up_tty_fops) | |
2578 | filp->f_op = &tty_fops; | |
2579 | goto retry_open; | |
2580 | } | |
24ec839c PZ |
2581 | |
2582 | mutex_lock(&tty_mutex); | |
2583 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2584 | if (!noctty && |
2585 | current->signal->leader && | |
2586 | !current->signal->tty && | |
24ec839c PZ |
2587 | tty->session == 0) |
2588 | __proc_set_tty(current, tty); | |
2589 | spin_unlock_irq(¤t->sighand->siglock); | |
2590 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
2591 | return 0; |
2592 | } | |
2593 | ||
2594 | #ifdef CONFIG_UNIX98_PTYS | |
af9b897e AC |
2595 | /** |
2596 | * ptmx_open - open a unix 98 pty master | |
2597 | * @inode: inode of device file | |
2598 | * @filp: file pointer to tty | |
2599 | * | |
2600 | * Allocate a unix98 pty master device from the ptmx driver. | |
2601 | * | |
2602 | * Locking: tty_mutex protects theinit_dev work. tty->count should | |
2603 | protect the rest. | |
2604 | * allocated_ptys_lock handles the list of free pty numbers | |
2605 | */ | |
2606 | ||
1da177e4 LT |
2607 | static int ptmx_open(struct inode * inode, struct file * filp) |
2608 | { | |
2609 | struct tty_struct *tty; | |
2610 | int retval; | |
2611 | int index; | |
2612 | int idr_ret; | |
2613 | ||
2614 | nonseekable_open(inode, filp); | |
2615 | ||
2616 | /* find a device that is not in use. */ | |
2617 | down(&allocated_ptys_lock); | |
2618 | if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { | |
2619 | up(&allocated_ptys_lock); | |
2620 | return -ENOMEM; | |
2621 | } | |
2622 | idr_ret = idr_get_new(&allocated_ptys, NULL, &index); | |
2623 | if (idr_ret < 0) { | |
2624 | up(&allocated_ptys_lock); | |
2625 | if (idr_ret == -EAGAIN) | |
2626 | return -ENOMEM; | |
2627 | return -EIO; | |
2628 | } | |
2629 | if (index >= pty_limit) { | |
2630 | idr_remove(&allocated_ptys, index); | |
2631 | up(&allocated_ptys_lock); | |
2632 | return -EIO; | |
2633 | } | |
2634 | up(&allocated_ptys_lock); | |
2635 | ||
70522e12 | 2636 | mutex_lock(&tty_mutex); |
1da177e4 | 2637 | retval = init_dev(ptm_driver, index, &tty); |
70522e12 | 2638 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2639 | |
2640 | if (retval) | |
2641 | goto out; | |
2642 | ||
2643 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
2644 | filp->private_data = tty; | |
2645 | file_move(filp, &tty->tty_files); | |
2646 | ||
2647 | retval = -ENOMEM; | |
2648 | if (devpts_pty_new(tty->link)) | |
2649 | goto out1; | |
2650 | ||
2651 | check_tty_count(tty, "tty_open"); | |
2652 | retval = ptm_driver->open(tty, filp); | |
2653 | if (!retval) | |
2654 | return 0; | |
2655 | out1: | |
2656 | release_dev(filp); | |
9453a5ad | 2657 | return retval; |
1da177e4 LT |
2658 | out: |
2659 | down(&allocated_ptys_lock); | |
2660 | idr_remove(&allocated_ptys, index); | |
2661 | up(&allocated_ptys_lock); | |
2662 | return retval; | |
2663 | } | |
2664 | #endif | |
2665 | ||
af9b897e AC |
2666 | /** |
2667 | * tty_release - vfs callback for close | |
2668 | * @inode: inode of tty | |
2669 | * @filp: file pointer for handle to tty | |
2670 | * | |
2671 | * Called the last time each file handle is closed that references | |
2672 | * this tty. There may however be several such references. | |
2673 | * | |
2674 | * Locking: | |
2675 | * Takes bkl. See release_dev | |
2676 | */ | |
2677 | ||
1da177e4 LT |
2678 | static int tty_release(struct inode * inode, struct file * filp) |
2679 | { | |
2680 | lock_kernel(); | |
2681 | release_dev(filp); | |
2682 | unlock_kernel(); | |
2683 | return 0; | |
2684 | } | |
2685 | ||
af9b897e AC |
2686 | /** |
2687 | * tty_poll - check tty status | |
2688 | * @filp: file being polled | |
2689 | * @wait: poll wait structures to update | |
2690 | * | |
2691 | * Call the line discipline polling method to obtain the poll | |
2692 | * status of the device. | |
2693 | * | |
2694 | * Locking: locks called line discipline but ldisc poll method | |
2695 | * may be re-entered freely by other callers. | |
2696 | */ | |
2697 | ||
1da177e4 LT |
2698 | static unsigned int tty_poll(struct file * filp, poll_table * wait) |
2699 | { | |
2700 | struct tty_struct * tty; | |
2701 | struct tty_ldisc *ld; | |
2702 | int ret = 0; | |
2703 | ||
2704 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2705 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) |
1da177e4 LT |
2706 | return 0; |
2707 | ||
2708 | ld = tty_ldisc_ref_wait(tty); | |
2709 | if (ld->poll) | |
2710 | ret = (ld->poll)(tty, filp, wait); | |
2711 | tty_ldisc_deref(ld); | |
2712 | return ret; | |
2713 | } | |
2714 | ||
2715 | static int tty_fasync(int fd, struct file * filp, int on) | |
2716 | { | |
2717 | struct tty_struct * tty; | |
2718 | int retval; | |
2719 | ||
2720 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2721 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) |
1da177e4 LT |
2722 | return 0; |
2723 | ||
2724 | retval = fasync_helper(fd, filp, on, &tty->fasync); | |
2725 | if (retval <= 0) | |
2726 | return retval; | |
2727 | ||
2728 | if (on) { | |
2729 | if (!waitqueue_active(&tty->read_wait)) | |
2730 | tty->minimum_to_wake = 1; | |
2731 | retval = f_setown(filp, (-tty->pgrp) ? : current->pid, 0); | |
2732 | if (retval) | |
2733 | return retval; | |
2734 | } else { | |
2735 | if (!tty->fasync && !waitqueue_active(&tty->read_wait)) | |
2736 | tty->minimum_to_wake = N_TTY_BUF_SIZE; | |
2737 | } | |
2738 | return 0; | |
2739 | } | |
2740 | ||
af9b897e AC |
2741 | /** |
2742 | * tiocsti - fake input character | |
2743 | * @tty: tty to fake input into | |
2744 | * @p: pointer to character | |
2745 | * | |
2746 | * Fake input to a tty device. Does the neccessary locking and | |
2747 | * input management. | |
2748 | * | |
2749 | * FIXME: does not honour flow control ?? | |
2750 | * | |
2751 | * Locking: | |
2752 | * Called functions take tty_ldisc_lock | |
2753 | * current->signal->tty check is safe without locks | |
28298232 AC |
2754 | * |
2755 | * FIXME: may race normal receive processing | |
af9b897e AC |
2756 | */ |
2757 | ||
1da177e4 LT |
2758 | static int tiocsti(struct tty_struct *tty, char __user *p) |
2759 | { | |
2760 | char ch, mbz = 0; | |
2761 | struct tty_ldisc *ld; | |
2762 | ||
2763 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) | |
2764 | return -EPERM; | |
2765 | if (get_user(ch, p)) | |
2766 | return -EFAULT; | |
2767 | ld = tty_ldisc_ref_wait(tty); | |
2768 | ld->receive_buf(tty, &ch, &mbz, 1); | |
2769 | tty_ldisc_deref(ld); | |
2770 | return 0; | |
2771 | } | |
2772 | ||
af9b897e AC |
2773 | /** |
2774 | * tiocgwinsz - implement window query ioctl | |
2775 | * @tty; tty | |
2776 | * @arg: user buffer for result | |
2777 | * | |
808a0d38 | 2778 | * Copies the kernel idea of the window size into the user buffer. |
af9b897e | 2779 | * |
24ec839c | 2780 | * Locking: tty->termios_mutex is taken to ensure the winsize data |
808a0d38 | 2781 | * is consistent. |
af9b897e AC |
2782 | */ |
2783 | ||
1da177e4 LT |
2784 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) |
2785 | { | |
808a0d38 AC |
2786 | int err; |
2787 | ||
5785c95b | 2788 | mutex_lock(&tty->termios_mutex); |
808a0d38 | 2789 | err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); |
5785c95b | 2790 | mutex_unlock(&tty->termios_mutex); |
808a0d38 AC |
2791 | |
2792 | return err ? -EFAULT: 0; | |
1da177e4 LT |
2793 | } |
2794 | ||
af9b897e AC |
2795 | /** |
2796 | * tiocswinsz - implement window size set ioctl | |
2797 | * @tty; tty | |
2798 | * @arg: user buffer for result | |
2799 | * | |
2800 | * Copies the user idea of the window size to the kernel. Traditionally | |
2801 | * this is just advisory information but for the Linux console it | |
2802 | * actually has driver level meaning and triggers a VC resize. | |
2803 | * | |
2804 | * Locking: | |
ca9bda00 AC |
2805 | * Called function use the console_sem is used to ensure we do |
2806 | * not try and resize the console twice at once. | |
24ec839c PZ |
2807 | * The tty->termios_mutex is used to ensure we don't double |
2808 | * resize and get confused. Lock order - tty->termios_mutex before | |
ca9bda00 | 2809 | * console sem |
af9b897e AC |
2810 | */ |
2811 | ||
1da177e4 LT |
2812 | static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, |
2813 | struct winsize __user * arg) | |
2814 | { | |
2815 | struct winsize tmp_ws; | |
2816 | ||
2817 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
2818 | return -EFAULT; | |
ca9bda00 | 2819 | |
5785c95b | 2820 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 2821 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
ca9bda00 AC |
2822 | goto done; |
2823 | ||
1da177e4 LT |
2824 | #ifdef CONFIG_VT |
2825 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { | |
5785c95b AV |
2826 | if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, |
2827 | tmp_ws.ws_row)) { | |
2828 | mutex_unlock(&tty->termios_mutex); | |
ca9bda00 AC |
2829 | return -ENXIO; |
2830 | } | |
1da177e4 LT |
2831 | } |
2832 | #endif | |
2833 | if (tty->pgrp > 0) | |
2834 | kill_pg(tty->pgrp, SIGWINCH, 1); | |
2835 | if ((real_tty->pgrp != tty->pgrp) && (real_tty->pgrp > 0)) | |
2836 | kill_pg(real_tty->pgrp, SIGWINCH, 1); | |
2837 | tty->winsize = tmp_ws; | |
2838 | real_tty->winsize = tmp_ws; | |
ca9bda00 | 2839 | done: |
5785c95b | 2840 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
2841 | return 0; |
2842 | } | |
2843 | ||
af9b897e AC |
2844 | /** |
2845 | * tioccons - allow admin to move logical console | |
2846 | * @file: the file to become console | |
2847 | * | |
2848 | * Allow the adminstrator to move the redirected console device | |
2849 | * | |
2850 | * Locking: uses redirect_lock to guard the redirect information | |
2851 | */ | |
2852 | ||
1da177e4 LT |
2853 | static int tioccons(struct file *file) |
2854 | { | |
2855 | if (!capable(CAP_SYS_ADMIN)) | |
2856 | return -EPERM; | |
2857 | if (file->f_op->write == redirected_tty_write) { | |
2858 | struct file *f; | |
2859 | spin_lock(&redirect_lock); | |
2860 | f = redirect; | |
2861 | redirect = NULL; | |
2862 | spin_unlock(&redirect_lock); | |
2863 | if (f) | |
2864 | fput(f); | |
2865 | return 0; | |
2866 | } | |
2867 | spin_lock(&redirect_lock); | |
2868 | if (redirect) { | |
2869 | spin_unlock(&redirect_lock); | |
2870 | return -EBUSY; | |
2871 | } | |
2872 | get_file(file); | |
2873 | redirect = file; | |
2874 | spin_unlock(&redirect_lock); | |
2875 | return 0; | |
2876 | } | |
2877 | ||
af9b897e AC |
2878 | /** |
2879 | * fionbio - non blocking ioctl | |
2880 | * @file: file to set blocking value | |
2881 | * @p: user parameter | |
2882 | * | |
2883 | * Historical tty interfaces had a blocking control ioctl before | |
2884 | * the generic functionality existed. This piece of history is preserved | |
2885 | * in the expected tty API of posix OS's. | |
2886 | * | |
2887 | * Locking: none, the open fle handle ensures it won't go away. | |
2888 | */ | |
1da177e4 LT |
2889 | |
2890 | static int fionbio(struct file *file, int __user *p) | |
2891 | { | |
2892 | int nonblock; | |
2893 | ||
2894 | if (get_user(nonblock, p)) | |
2895 | return -EFAULT; | |
2896 | ||
2897 | if (nonblock) | |
2898 | file->f_flags |= O_NONBLOCK; | |
2899 | else | |
2900 | file->f_flags &= ~O_NONBLOCK; | |
2901 | return 0; | |
2902 | } | |
2903 | ||
af9b897e AC |
2904 | /** |
2905 | * tiocsctty - set controlling tty | |
2906 | * @tty: tty structure | |
2907 | * @arg: user argument | |
2908 | * | |
2909 | * This ioctl is used to manage job control. It permits a session | |
2910 | * leader to set this tty as the controlling tty for the session. | |
2911 | * | |
2912 | * Locking: | |
28298232 | 2913 | * Takes tty_mutex() to protect tty instance |
24ec839c PZ |
2914 | * Takes tasklist_lock internally to walk sessions |
2915 | * Takes ->siglock() when updating signal->tty | |
af9b897e AC |
2916 | */ |
2917 | ||
1da177e4 LT |
2918 | static int tiocsctty(struct tty_struct *tty, int arg) |
2919 | { | |
24ec839c | 2920 | int ret = 0; |
1da177e4 | 2921 | if (current->signal->leader && |
937949d9 | 2922 | (process_session(current) == tty->session)) |
24ec839c PZ |
2923 | return ret; |
2924 | ||
2925 | mutex_lock(&tty_mutex); | |
1da177e4 LT |
2926 | /* |
2927 | * The process must be a session leader and | |
2928 | * not have a controlling tty already. | |
2929 | */ | |
24ec839c PZ |
2930 | if (!current->signal->leader || current->signal->tty) { |
2931 | ret = -EPERM; | |
2932 | goto unlock; | |
2933 | } | |
2934 | ||
1da177e4 LT |
2935 | if (tty->session > 0) { |
2936 | /* | |
2937 | * This tty is already the controlling | |
2938 | * tty for another session group! | |
2939 | */ | |
2940 | if ((arg == 1) && capable(CAP_SYS_ADMIN)) { | |
2941 | /* | |
2942 | * Steal it away | |
2943 | */ | |
1da177e4 | 2944 | read_lock(&tasklist_lock); |
24ec839c | 2945 | session_clear_tty(tty->session); |
1da177e4 | 2946 | read_unlock(&tasklist_lock); |
24ec839c PZ |
2947 | } else { |
2948 | ret = -EPERM; | |
2949 | goto unlock; | |
2950 | } | |
1da177e4 | 2951 | } |
24ec839c PZ |
2952 | proc_set_tty(current, tty); |
2953 | unlock: | |
28298232 | 2954 | mutex_unlock(&tty_mutex); |
24ec839c | 2955 | return ret; |
1da177e4 LT |
2956 | } |
2957 | ||
af9b897e AC |
2958 | /** |
2959 | * tiocgpgrp - get process group | |
2960 | * @tty: tty passed by user | |
2961 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
2962 | * @p: returned pid | |
2963 | * | |
2964 | * Obtain the process group of the tty. If there is no process group | |
2965 | * return an error. | |
2966 | * | |
24ec839c | 2967 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
2968 | */ |
2969 | ||
1da177e4 LT |
2970 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
2971 | { | |
2972 | /* | |
2973 | * (tty == real_tty) is a cheap way of | |
2974 | * testing if the tty is NOT a master pty. | |
2975 | */ | |
2976 | if (tty == real_tty && current->signal->tty != real_tty) | |
2977 | return -ENOTTY; | |
2978 | return put_user(real_tty->pgrp, p); | |
2979 | } | |
2980 | ||
af9b897e AC |
2981 | /** |
2982 | * tiocspgrp - attempt to set process group | |
2983 | * @tty: tty passed by user | |
2984 | * @real_tty: tty side device matching tty passed by user | |
2985 | * @p: pid pointer | |
2986 | * | |
2987 | * Set the process group of the tty to the session passed. Only | |
2988 | * permitted where the tty session is our session. | |
2989 | * | |
2990 | * Locking: None | |
af9b897e AC |
2991 | */ |
2992 | ||
1da177e4 LT |
2993 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
2994 | { | |
2995 | pid_t pgrp; | |
2996 | int retval = tty_check_change(real_tty); | |
2997 | ||
2998 | if (retval == -EIO) | |
2999 | return -ENOTTY; | |
3000 | if (retval) | |
3001 | return retval; | |
3002 | if (!current->signal->tty || | |
3003 | (current->signal->tty != real_tty) || | |
937949d9 | 3004 | (real_tty->session != process_session(current))) |
1da177e4 LT |
3005 | return -ENOTTY; |
3006 | if (get_user(pgrp, p)) | |
3007 | return -EFAULT; | |
3008 | if (pgrp < 0) | |
3009 | return -EINVAL; | |
937949d9 | 3010 | if (session_of_pgrp(pgrp) != process_session(current)) |
1da177e4 LT |
3011 | return -EPERM; |
3012 | real_tty->pgrp = pgrp; | |
3013 | return 0; | |
3014 | } | |
3015 | ||
af9b897e AC |
3016 | /** |
3017 | * tiocgsid - get session id | |
3018 | * @tty: tty passed by user | |
3019 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3020 | * @p: pointer to returned session id | |
3021 | * | |
3022 | * Obtain the session id of the tty. If there is no session | |
3023 | * return an error. | |
3024 | * | |
24ec839c | 3025 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3026 | */ |
3027 | ||
1da177e4 LT |
3028 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3029 | { | |
3030 | /* | |
3031 | * (tty == real_tty) is a cheap way of | |
3032 | * testing if the tty is NOT a master pty. | |
3033 | */ | |
3034 | if (tty == real_tty && current->signal->tty != real_tty) | |
3035 | return -ENOTTY; | |
3036 | if (real_tty->session <= 0) | |
3037 | return -ENOTTY; | |
3038 | return put_user(real_tty->session, p); | |
3039 | } | |
3040 | ||
af9b897e AC |
3041 | /** |
3042 | * tiocsetd - set line discipline | |
3043 | * @tty: tty device | |
3044 | * @p: pointer to user data | |
3045 | * | |
3046 | * Set the line discipline according to user request. | |
3047 | * | |
3048 | * Locking: see tty_set_ldisc, this function is just a helper | |
3049 | */ | |
3050 | ||
1da177e4 LT |
3051 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
3052 | { | |
3053 | int ldisc; | |
3054 | ||
3055 | if (get_user(ldisc, p)) | |
3056 | return -EFAULT; | |
3057 | return tty_set_ldisc(tty, ldisc); | |
3058 | } | |
3059 | ||
af9b897e AC |
3060 | /** |
3061 | * send_break - performed time break | |
3062 | * @tty: device to break on | |
3063 | * @duration: timeout in mS | |
3064 | * | |
3065 | * Perform a timed break on hardware that lacks its own driver level | |
3066 | * timed break functionality. | |
3067 | * | |
3068 | * Locking: | |
28298232 | 3069 | * atomic_write_lock serializes |
af9b897e | 3070 | * |
af9b897e AC |
3071 | */ |
3072 | ||
b20f3ae5 | 3073 | static int send_break(struct tty_struct *tty, unsigned int duration) |
1da177e4 | 3074 | { |
28298232 AC |
3075 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) |
3076 | return -EINTR; | |
1da177e4 LT |
3077 | tty->driver->break_ctl(tty, -1); |
3078 | if (!signal_pending(current)) { | |
b20f3ae5 | 3079 | msleep_interruptible(duration); |
1da177e4 LT |
3080 | } |
3081 | tty->driver->break_ctl(tty, 0); | |
28298232 | 3082 | mutex_unlock(&tty->atomic_write_lock); |
1da177e4 LT |
3083 | if (signal_pending(current)) |
3084 | return -EINTR; | |
3085 | return 0; | |
3086 | } | |
3087 | ||
af9b897e AC |
3088 | /** |
3089 | * tiocmget - get modem status | |
3090 | * @tty: tty device | |
3091 | * @file: user file pointer | |
3092 | * @p: pointer to result | |
3093 | * | |
3094 | * Obtain the modem status bits from the tty driver if the feature | |
3095 | * is supported. Return -EINVAL if it is not available. | |
3096 | * | |
3097 | * Locking: none (up to the driver) | |
3098 | */ | |
3099 | ||
3100 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) | |
1da177e4 LT |
3101 | { |
3102 | int retval = -EINVAL; | |
3103 | ||
3104 | if (tty->driver->tiocmget) { | |
3105 | retval = tty->driver->tiocmget(tty, file); | |
3106 | ||
3107 | if (retval >= 0) | |
3108 | retval = put_user(retval, p); | |
3109 | } | |
3110 | return retval; | |
3111 | } | |
3112 | ||
af9b897e AC |
3113 | /** |
3114 | * tiocmset - set modem status | |
3115 | * @tty: tty device | |
3116 | * @file: user file pointer | |
3117 | * @cmd: command - clear bits, set bits or set all | |
3118 | * @p: pointer to desired bits | |
3119 | * | |
3120 | * Set the modem status bits from the tty driver if the feature | |
3121 | * is supported. Return -EINVAL if it is not available. | |
3122 | * | |
3123 | * Locking: none (up to the driver) | |
3124 | */ | |
3125 | ||
3126 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, | |
1da177e4 LT |
3127 | unsigned __user *p) |
3128 | { | |
3129 | int retval = -EINVAL; | |
3130 | ||
3131 | if (tty->driver->tiocmset) { | |
3132 | unsigned int set, clear, val; | |
3133 | ||
3134 | retval = get_user(val, p); | |
3135 | if (retval) | |
3136 | return retval; | |
3137 | ||
3138 | set = clear = 0; | |
3139 | switch (cmd) { | |
3140 | case TIOCMBIS: | |
3141 | set = val; | |
3142 | break; | |
3143 | case TIOCMBIC: | |
3144 | clear = val; | |
3145 | break; | |
3146 | case TIOCMSET: | |
3147 | set = val; | |
3148 | clear = ~val; | |
3149 | break; | |
3150 | } | |
3151 | ||
3152 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3153 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3154 | ||
3155 | retval = tty->driver->tiocmset(tty, file, set, clear); | |
3156 | } | |
3157 | return retval; | |
3158 | } | |
3159 | ||
3160 | /* | |
3161 | * Split this up, as gcc can choke on it otherwise.. | |
3162 | */ | |
3163 | int tty_ioctl(struct inode * inode, struct file * file, | |
3164 | unsigned int cmd, unsigned long arg) | |
3165 | { | |
3166 | struct tty_struct *tty, *real_tty; | |
3167 | void __user *p = (void __user *)arg; | |
3168 | int retval; | |
3169 | struct tty_ldisc *ld; | |
3170 | ||
3171 | tty = (struct tty_struct *)file->private_data; | |
3172 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3173 | return -EINVAL; | |
3174 | ||
28298232 AC |
3175 | /* CHECKME: is this safe as one end closes ? */ |
3176 | ||
1da177e4 LT |
3177 | real_tty = tty; |
3178 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
3179 | tty->driver->subtype == PTY_TYPE_MASTER) | |
3180 | real_tty = tty->link; | |
3181 | ||
3182 | /* | |
3183 | * Break handling by driver | |
3184 | */ | |
3185 | if (!tty->driver->break_ctl) { | |
3186 | switch(cmd) { | |
3187 | case TIOCSBRK: | |
3188 | case TIOCCBRK: | |
3189 | if (tty->driver->ioctl) | |
3190 | return tty->driver->ioctl(tty, file, cmd, arg); | |
3191 | return -EINVAL; | |
3192 | ||
3193 | /* These two ioctl's always return success; even if */ | |
3194 | /* the driver doesn't support them. */ | |
3195 | case TCSBRK: | |
3196 | case TCSBRKP: | |
3197 | if (!tty->driver->ioctl) | |
3198 | return 0; | |
3199 | retval = tty->driver->ioctl(tty, file, cmd, arg); | |
3200 | if (retval == -ENOIOCTLCMD) | |
3201 | retval = 0; | |
3202 | return retval; | |
3203 | } | |
3204 | } | |
3205 | ||
3206 | /* | |
3207 | * Factor out some common prep work | |
3208 | */ | |
3209 | switch (cmd) { | |
3210 | case TIOCSETD: | |
3211 | case TIOCSBRK: | |
3212 | case TIOCCBRK: | |
3213 | case TCSBRK: | |
3214 | case TCSBRKP: | |
3215 | retval = tty_check_change(tty); | |
3216 | if (retval) | |
3217 | return retval; | |
3218 | if (cmd != TIOCCBRK) { | |
3219 | tty_wait_until_sent(tty, 0); | |
3220 | if (signal_pending(current)) | |
3221 | return -EINTR; | |
3222 | } | |
3223 | break; | |
3224 | } | |
3225 | ||
3226 | switch (cmd) { | |
3227 | case TIOCSTI: | |
3228 | return tiocsti(tty, p); | |
3229 | case TIOCGWINSZ: | |
3230 | return tiocgwinsz(tty, p); | |
3231 | case TIOCSWINSZ: | |
3232 | return tiocswinsz(tty, real_tty, p); | |
3233 | case TIOCCONS: | |
3234 | return real_tty!=tty ? -EINVAL : tioccons(file); | |
3235 | case FIONBIO: | |
3236 | return fionbio(file, p); | |
3237 | case TIOCEXCL: | |
3238 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
3239 | return 0; | |
3240 | case TIOCNXCL: | |
3241 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
3242 | return 0; | |
3243 | case TIOCNOTTY: | |
3244 | if (current->signal->tty != tty) | |
3245 | return -ENOTTY; | |
3246 | if (current->signal->leader) | |
3247 | disassociate_ctty(0); | |
24ec839c | 3248 | proc_clear_tty(current); |
1da177e4 LT |
3249 | return 0; |
3250 | case TIOCSCTTY: | |
3251 | return tiocsctty(tty, arg); | |
3252 | case TIOCGPGRP: | |
3253 | return tiocgpgrp(tty, real_tty, p); | |
3254 | case TIOCSPGRP: | |
3255 | return tiocspgrp(tty, real_tty, p); | |
3256 | case TIOCGSID: | |
3257 | return tiocgsid(tty, real_tty, p); | |
3258 | case TIOCGETD: | |
3259 | /* FIXME: check this is ok */ | |
3260 | return put_user(tty->ldisc.num, (int __user *)p); | |
3261 | case TIOCSETD: | |
3262 | return tiocsetd(tty, p); | |
3263 | #ifdef CONFIG_VT | |
3264 | case TIOCLINUX: | |
3265 | return tioclinux(tty, arg); | |
3266 | #endif | |
3267 | /* | |
3268 | * Break handling | |
3269 | */ | |
3270 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
3271 | tty->driver->break_ctl(tty, -1); | |
3272 | return 0; | |
3273 | ||
3274 | case TIOCCBRK: /* Turn break off, unconditionally */ | |
3275 | tty->driver->break_ctl(tty, 0); | |
3276 | return 0; | |
3277 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
283fef59 PF |
3278 | /* non-zero arg means wait for all output data |
3279 | * to be sent (performed above) but don't send break. | |
3280 | * This is used by the tcdrain() termios function. | |
1da177e4 LT |
3281 | */ |
3282 | if (!arg) | |
b20f3ae5 | 3283 | return send_break(tty, 250); |
1da177e4 LT |
3284 | return 0; |
3285 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
b20f3ae5 | 3286 | return send_break(tty, arg ? arg*100 : 250); |
1da177e4 LT |
3287 | |
3288 | case TIOCMGET: | |
3289 | return tty_tiocmget(tty, file, p); | |
3290 | ||
3291 | case TIOCMSET: | |
3292 | case TIOCMBIC: | |
3293 | case TIOCMBIS: | |
3294 | return tty_tiocmset(tty, file, cmd, p); | |
3295 | } | |
3296 | if (tty->driver->ioctl) { | |
3297 | retval = (tty->driver->ioctl)(tty, file, cmd, arg); | |
3298 | if (retval != -ENOIOCTLCMD) | |
3299 | return retval; | |
3300 | } | |
3301 | ld = tty_ldisc_ref_wait(tty); | |
3302 | retval = -EINVAL; | |
3303 | if (ld->ioctl) { | |
3304 | retval = ld->ioctl(tty, file, cmd, arg); | |
3305 | if (retval == -ENOIOCTLCMD) | |
3306 | retval = -EINVAL; | |
3307 | } | |
3308 | tty_ldisc_deref(ld); | |
3309 | return retval; | |
3310 | } | |
3311 | ||
3312 | ||
3313 | /* | |
3314 | * This implements the "Secure Attention Key" --- the idea is to | |
3315 | * prevent trojan horses by killing all processes associated with this | |
3316 | * tty when the user hits the "Secure Attention Key". Required for | |
3317 | * super-paranoid applications --- see the Orange Book for more details. | |
3318 | * | |
3319 | * This code could be nicer; ideally it should send a HUP, wait a few | |
3320 | * seconds, then send a INT, and then a KILL signal. But you then | |
3321 | * have to coordinate with the init process, since all processes associated | |
3322 | * with the current tty must be dead before the new getty is allowed | |
3323 | * to spawn. | |
3324 | * | |
3325 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
3326 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
3327 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
3328 | * | |
3329 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
3330 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
3331 | */ | |
8b6312f4 | 3332 | void __do_SAK(struct tty_struct *tty) |
1da177e4 LT |
3333 | { |
3334 | #ifdef TTY_SOFT_SAK | |
3335 | tty_hangup(tty); | |
3336 | #else | |
652486fb | 3337 | struct task_struct *g, *p; |
1da177e4 LT |
3338 | int session; |
3339 | int i; | |
3340 | struct file *filp; | |
badf1662 | 3341 | struct fdtable *fdt; |
1da177e4 LT |
3342 | |
3343 | if (!tty) | |
3344 | return; | |
24ec839c | 3345 | session = tty->session; |
1da177e4 | 3346 | |
b3f13deb | 3347 | tty_ldisc_flush(tty); |
1da177e4 LT |
3348 | |
3349 | if (tty->driver->flush_buffer) | |
3350 | tty->driver->flush_buffer(tty); | |
3351 | ||
3352 | read_lock(&tasklist_lock); | |
652486fb | 3353 | /* Kill the entire session */ |
1da177e4 | 3354 | do_each_task_pid(session, PIDTYPE_SID, p) { |
652486fb | 3355 | printk(KERN_NOTICE "SAK: killed process %d" |
937949d9 | 3356 | " (%s): process_session(p)==tty->session\n", |
652486fb EB |
3357 | p->pid, p->comm); |
3358 | send_sig(SIGKILL, p, 1); | |
3359 | } while_each_task_pid(session, PIDTYPE_SID, p); | |
3360 | /* Now kill any processes that happen to have the | |
3361 | * tty open. | |
3362 | */ | |
3363 | do_each_thread(g, p) { | |
3364 | if (p->signal->tty == tty) { | |
1da177e4 | 3365 | printk(KERN_NOTICE "SAK: killed process %d" |
937949d9 | 3366 | " (%s): process_session(p)==tty->session\n", |
1da177e4 LT |
3367 | p->pid, p->comm); |
3368 | send_sig(SIGKILL, p, 1); | |
3369 | continue; | |
3370 | } | |
3371 | task_lock(p); | |
3372 | if (p->files) { | |
ca99c1da DS |
3373 | /* |
3374 | * We don't take a ref to the file, so we must | |
3375 | * hold ->file_lock instead. | |
3376 | */ | |
3377 | spin_lock(&p->files->file_lock); | |
badf1662 DS |
3378 | fdt = files_fdtable(p->files); |
3379 | for (i=0; i < fdt->max_fds; i++) { | |
1da177e4 LT |
3380 | filp = fcheck_files(p->files, i); |
3381 | if (!filp) | |
3382 | continue; | |
3383 | if (filp->f_op->read == tty_read && | |
3384 | filp->private_data == tty) { | |
3385 | printk(KERN_NOTICE "SAK: killed process %d" | |
3386 | " (%s): fd#%d opened to the tty\n", | |
3387 | p->pid, p->comm, i); | |
20ac9437 | 3388 | force_sig(SIGKILL, p); |
1da177e4 LT |
3389 | break; |
3390 | } | |
3391 | } | |
ca99c1da | 3392 | spin_unlock(&p->files->file_lock); |
1da177e4 LT |
3393 | } |
3394 | task_unlock(p); | |
652486fb | 3395 | } while_each_thread(g, p); |
1da177e4 LT |
3396 | read_unlock(&tasklist_lock); |
3397 | #endif | |
3398 | } | |
3399 | ||
8b6312f4 EB |
3400 | static void do_SAK_work(struct work_struct *work) |
3401 | { | |
3402 | struct tty_struct *tty = | |
3403 | container_of(work, struct tty_struct, SAK_work); | |
3404 | __do_SAK(tty); | |
3405 | } | |
3406 | ||
1da177e4 LT |
3407 | /* |
3408 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
3409 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
3410 | * the values which we write to it will be identical to the values which it | |
3411 | * already has. --akpm | |
3412 | */ | |
3413 | void do_SAK(struct tty_struct *tty) | |
3414 | { | |
3415 | if (!tty) | |
3416 | return; | |
8b6312f4 | 3417 | PREPARE_WORK(&tty->SAK_work, do_SAK_work); |
1da177e4 LT |
3418 | schedule_work(&tty->SAK_work); |
3419 | } | |
3420 | ||
3421 | EXPORT_SYMBOL(do_SAK); | |
3422 | ||
af9b897e AC |
3423 | /** |
3424 | * flush_to_ldisc | |
65f27f38 | 3425 | * @work: tty structure passed from work queue. |
af9b897e AC |
3426 | * |
3427 | * This routine is called out of the software interrupt to flush data | |
3428 | * from the buffer chain to the line discipline. | |
3429 | * | |
3430 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
3431 | * while invoking the line discipline receive_buf method. The | |
3432 | * receive_buf method is single threaded for each tty instance. | |
1da177e4 LT |
3433 | */ |
3434 | ||
65f27f38 | 3435 | static void flush_to_ldisc(struct work_struct *work) |
1da177e4 | 3436 | { |
65f27f38 DH |
3437 | struct tty_struct *tty = |
3438 | container_of(work, struct tty_struct, buf.work.work); | |
1da177e4 LT |
3439 | unsigned long flags; |
3440 | struct tty_ldisc *disc; | |
2c3bb20f | 3441 | struct tty_buffer *tbuf, *head; |
8977d929 PF |
3442 | char *char_buf; |
3443 | unsigned char *flag_buf; | |
1da177e4 LT |
3444 | |
3445 | disc = tty_ldisc_ref(tty); | |
3446 | if (disc == NULL) /* !TTY_LDISC */ | |
3447 | return; | |
3448 | ||
808249ce | 3449 | spin_lock_irqsave(&tty->buf.lock, flags); |
2c3bb20f PF |
3450 | head = tty->buf.head; |
3451 | if (head != NULL) { | |
3452 | tty->buf.head = NULL; | |
3453 | for (;;) { | |
3454 | int count = head->commit - head->read; | |
3455 | if (!count) { | |
3456 | if (head->next == NULL) | |
3457 | break; | |
3458 | tbuf = head; | |
3459 | head = head->next; | |
3460 | tty_buffer_free(tty, tbuf); | |
3461 | continue; | |
3462 | } | |
3463 | if (!tty->receive_room) { | |
3464 | schedule_delayed_work(&tty->buf.work, 1); | |
3465 | break; | |
3466 | } | |
3467 | if (count > tty->receive_room) | |
3468 | count = tty->receive_room; | |
3469 | char_buf = head->char_buf_ptr + head->read; | |
3470 | flag_buf = head->flag_buf_ptr + head->read; | |
3471 | head->read += count; | |
8977d929 PF |
3472 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3473 | disc->receive_buf(tty, char_buf, flag_buf, count); | |
3474 | spin_lock_irqsave(&tty->buf.lock, flags); | |
3475 | } | |
2c3bb20f | 3476 | tty->buf.head = head; |
33f0f88f | 3477 | } |
808249ce | 3478 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
817d6d3b | 3479 | |
1da177e4 LT |
3480 | tty_ldisc_deref(disc); |
3481 | } | |
3482 | ||
1da177e4 LT |
3483 | /** |
3484 | * tty_flip_buffer_push - terminal | |
3485 | * @tty: tty to push | |
3486 | * | |
3487 | * Queue a push of the terminal flip buffers to the line discipline. This | |
3488 | * function must not be called from IRQ context if tty->low_latency is set. | |
3489 | * | |
3490 | * In the event of the queue being busy for flipping the work will be | |
3491 | * held off and retried later. | |
af9b897e AC |
3492 | * |
3493 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
1da177e4 LT |
3494 | */ |
3495 | ||
3496 | void tty_flip_buffer_push(struct tty_struct *tty) | |
3497 | { | |
808249ce PF |
3498 | unsigned long flags; |
3499 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 3500 | if (tty->buf.tail != NULL) |
8977d929 | 3501 | tty->buf.tail->commit = tty->buf.tail->used; |
808249ce PF |
3502 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3503 | ||
1da177e4 | 3504 | if (tty->low_latency) |
65f27f38 | 3505 | flush_to_ldisc(&tty->buf.work.work); |
1da177e4 | 3506 | else |
33f0f88f | 3507 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
3508 | } |
3509 | ||
3510 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
3511 | ||
33f0f88f | 3512 | |
af9b897e AC |
3513 | /** |
3514 | * initialize_tty_struct | |
3515 | * @tty: tty to initialize | |
3516 | * | |
3517 | * This subroutine initializes a tty structure that has been newly | |
3518 | * allocated. | |
3519 | * | |
3520 | * Locking: none - tty in question must not be exposed at this point | |
1da177e4 | 3521 | */ |
af9b897e | 3522 | |
1da177e4 LT |
3523 | static void initialize_tty_struct(struct tty_struct *tty) |
3524 | { | |
3525 | memset(tty, 0, sizeof(struct tty_struct)); | |
3526 | tty->magic = TTY_MAGIC; | |
3527 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
3528 | tty->pgrp = -1; | |
3529 | tty->overrun_time = jiffies; | |
33f0f88f AC |
3530 | tty->buf.head = tty->buf.tail = NULL; |
3531 | tty_buffer_init(tty); | |
65f27f38 | 3532 | INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); |
33f0f88f | 3533 | init_MUTEX(&tty->buf.pty_sem); |
5785c95b | 3534 | mutex_init(&tty->termios_mutex); |
1da177e4 LT |
3535 | init_waitqueue_head(&tty->write_wait); |
3536 | init_waitqueue_head(&tty->read_wait); | |
65f27f38 | 3537 | INIT_WORK(&tty->hangup_work, do_tty_hangup); |
70522e12 IM |
3538 | mutex_init(&tty->atomic_read_lock); |
3539 | mutex_init(&tty->atomic_write_lock); | |
1da177e4 LT |
3540 | spin_lock_init(&tty->read_lock); |
3541 | INIT_LIST_HEAD(&tty->tty_files); | |
65f27f38 | 3542 | INIT_WORK(&tty->SAK_work, NULL); |
1da177e4 LT |
3543 | } |
3544 | ||
3545 | /* | |
3546 | * The default put_char routine if the driver did not define one. | |
3547 | */ | |
af9b897e | 3548 | |
1da177e4 LT |
3549 | static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) |
3550 | { | |
3551 | tty->driver->write(tty, &ch, 1); | |
3552 | } | |
3553 | ||
7fe845d1 | 3554 | static struct class *tty_class; |
1da177e4 LT |
3555 | |
3556 | /** | |
af9b897e AC |
3557 | * tty_register_device - register a tty device |
3558 | * @driver: the tty driver that describes the tty device | |
3559 | * @index: the index in the tty driver for this tty device | |
3560 | * @device: a struct device that is associated with this tty device. | |
3561 | * This field is optional, if there is no known struct device | |
3562 | * for this tty device it can be set to NULL safely. | |
1da177e4 | 3563 | * |
01107d34 GKH |
3564 | * Returns a pointer to the struct device for this tty device |
3565 | * (or ERR_PTR(-EFOO) on error). | |
1cdcb6b4 | 3566 | * |
af9b897e AC |
3567 | * This call is required to be made to register an individual tty device |
3568 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
3569 | * that bit is not set, this function should not be called by a tty | |
3570 | * driver. | |
3571 | * | |
3572 | * Locking: ?? | |
1da177e4 | 3573 | */ |
af9b897e | 3574 | |
01107d34 GKH |
3575 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
3576 | struct device *device) | |
1da177e4 LT |
3577 | { |
3578 | char name[64]; | |
3579 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; | |
3580 | ||
3581 | if (index >= driver->num) { | |
3582 | printk(KERN_ERR "Attempt to register invalid tty line number " | |
3583 | " (%d).\n", index); | |
1cdcb6b4 | 3584 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
3585 | } |
3586 | ||
1da177e4 LT |
3587 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
3588 | pty_line_name(driver, index, name); | |
3589 | else | |
3590 | tty_line_name(driver, index, name); | |
1cdcb6b4 | 3591 | |
01107d34 | 3592 | return device_create(tty_class, device, dev, name); |
1da177e4 LT |
3593 | } |
3594 | ||
3595 | /** | |
af9b897e AC |
3596 | * tty_unregister_device - unregister a tty device |
3597 | * @driver: the tty driver that describes the tty device | |
3598 | * @index: the index in the tty driver for this tty device | |
1da177e4 | 3599 | * |
af9b897e AC |
3600 | * If a tty device is registered with a call to tty_register_device() then |
3601 | * this function must be called when the tty device is gone. | |
3602 | * | |
3603 | * Locking: ?? | |
1da177e4 | 3604 | */ |
af9b897e | 3605 | |
1da177e4 LT |
3606 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
3607 | { | |
01107d34 | 3608 | device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); |
1da177e4 LT |
3609 | } |
3610 | ||
3611 | EXPORT_SYMBOL(tty_register_device); | |
3612 | EXPORT_SYMBOL(tty_unregister_device); | |
3613 | ||
3614 | struct tty_driver *alloc_tty_driver(int lines) | |
3615 | { | |
3616 | struct tty_driver *driver; | |
3617 | ||
3618 | driver = kmalloc(sizeof(struct tty_driver), GFP_KERNEL); | |
3619 | if (driver) { | |
3620 | memset(driver, 0, sizeof(struct tty_driver)); | |
3621 | driver->magic = TTY_DRIVER_MAGIC; | |
3622 | driver->num = lines; | |
3623 | /* later we'll move allocation of tables here */ | |
3624 | } | |
3625 | return driver; | |
3626 | } | |
3627 | ||
3628 | void put_tty_driver(struct tty_driver *driver) | |
3629 | { | |
3630 | kfree(driver); | |
3631 | } | |
3632 | ||
b68e31d0 JD |
3633 | void tty_set_operations(struct tty_driver *driver, |
3634 | const struct tty_operations *op) | |
1da177e4 LT |
3635 | { |
3636 | driver->open = op->open; | |
3637 | driver->close = op->close; | |
3638 | driver->write = op->write; | |
3639 | driver->put_char = op->put_char; | |
3640 | driver->flush_chars = op->flush_chars; | |
3641 | driver->write_room = op->write_room; | |
3642 | driver->chars_in_buffer = op->chars_in_buffer; | |
3643 | driver->ioctl = op->ioctl; | |
3644 | driver->set_termios = op->set_termios; | |
3645 | driver->throttle = op->throttle; | |
3646 | driver->unthrottle = op->unthrottle; | |
3647 | driver->stop = op->stop; | |
3648 | driver->start = op->start; | |
3649 | driver->hangup = op->hangup; | |
3650 | driver->break_ctl = op->break_ctl; | |
3651 | driver->flush_buffer = op->flush_buffer; | |
3652 | driver->set_ldisc = op->set_ldisc; | |
3653 | driver->wait_until_sent = op->wait_until_sent; | |
3654 | driver->send_xchar = op->send_xchar; | |
3655 | driver->read_proc = op->read_proc; | |
3656 | driver->write_proc = op->write_proc; | |
3657 | driver->tiocmget = op->tiocmget; | |
3658 | driver->tiocmset = op->tiocmset; | |
3659 | } | |
3660 | ||
3661 | ||
3662 | EXPORT_SYMBOL(alloc_tty_driver); | |
3663 | EXPORT_SYMBOL(put_tty_driver); | |
3664 | EXPORT_SYMBOL(tty_set_operations); | |
3665 | ||
3666 | /* | |
3667 | * Called by a tty driver to register itself. | |
3668 | */ | |
3669 | int tty_register_driver(struct tty_driver *driver) | |
3670 | { | |
3671 | int error; | |
3672 | int i; | |
3673 | dev_t dev; | |
3674 | void **p = NULL; | |
3675 | ||
3676 | if (driver->flags & TTY_DRIVER_INSTALLED) | |
3677 | return 0; | |
3678 | ||
3679 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
3680 | p = kmalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); | |
3681 | if (!p) | |
3682 | return -ENOMEM; | |
3683 | memset(p, 0, driver->num * 3 * sizeof(void *)); | |
3684 | } | |
3685 | ||
3686 | if (!driver->major) { | |
3687 | error = alloc_chrdev_region(&dev, driver->minor_start, driver->num, | |
3688 | (char*)driver->name); | |
3689 | if (!error) { | |
3690 | driver->major = MAJOR(dev); | |
3691 | driver->minor_start = MINOR(dev); | |
3692 | } | |
3693 | } else { | |
3694 | dev = MKDEV(driver->major, driver->minor_start); | |
3695 | error = register_chrdev_region(dev, driver->num, | |
3696 | (char*)driver->name); | |
3697 | } | |
3698 | if (error < 0) { | |
3699 | kfree(p); | |
3700 | return error; | |
3701 | } | |
3702 | ||
3703 | if (p) { | |
3704 | driver->ttys = (struct tty_struct **)p; | |
edc6afc5 AC |
3705 | driver->termios = (struct ktermios **)(p + driver->num); |
3706 | driver->termios_locked = (struct ktermios **)(p + driver->num * 2); | |
1da177e4 LT |
3707 | } else { |
3708 | driver->ttys = NULL; | |
3709 | driver->termios = NULL; | |
3710 | driver->termios_locked = NULL; | |
3711 | } | |
3712 | ||
3713 | cdev_init(&driver->cdev, &tty_fops); | |
3714 | driver->cdev.owner = driver->owner; | |
3715 | error = cdev_add(&driver->cdev, dev, driver->num); | |
3716 | if (error) { | |
1da177e4 LT |
3717 | unregister_chrdev_region(dev, driver->num); |
3718 | driver->ttys = NULL; | |
3719 | driver->termios = driver->termios_locked = NULL; | |
3720 | kfree(p); | |
3721 | return error; | |
3722 | } | |
3723 | ||
3724 | if (!driver->put_char) | |
3725 | driver->put_char = tty_default_put_char; | |
3726 | ||
3727 | list_add(&driver->tty_drivers, &tty_drivers); | |
3728 | ||
331b8319 | 3729 | if ( !(driver->flags & TTY_DRIVER_DYNAMIC_DEV) ) { |
1da177e4 LT |
3730 | for(i = 0; i < driver->num; i++) |
3731 | tty_register_device(driver, i, NULL); | |
3732 | } | |
3733 | proc_tty_register_driver(driver); | |
3734 | return 0; | |
3735 | } | |
3736 | ||
3737 | EXPORT_SYMBOL(tty_register_driver); | |
3738 | ||
3739 | /* | |
3740 | * Called by a tty driver to unregister itself. | |
3741 | */ | |
3742 | int tty_unregister_driver(struct tty_driver *driver) | |
3743 | { | |
3744 | int i; | |
edc6afc5 | 3745 | struct ktermios *tp; |
1da177e4 LT |
3746 | void *p; |
3747 | ||
3748 | if (driver->refcount) | |
3749 | return -EBUSY; | |
3750 | ||
3751 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
3752 | driver->num); | |
3753 | ||
3754 | list_del(&driver->tty_drivers); | |
3755 | ||
3756 | /* | |
3757 | * Free the termios and termios_locked structures because | |
3758 | * we don't want to get memory leaks when modular tty | |
3759 | * drivers are removed from the kernel. | |
3760 | */ | |
3761 | for (i = 0; i < driver->num; i++) { | |
3762 | tp = driver->termios[i]; | |
3763 | if (tp) { | |
3764 | driver->termios[i] = NULL; | |
3765 | kfree(tp); | |
3766 | } | |
3767 | tp = driver->termios_locked[i]; | |
3768 | if (tp) { | |
3769 | driver->termios_locked[i] = NULL; | |
3770 | kfree(tp); | |
3771 | } | |
331b8319 | 3772 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
1da177e4 LT |
3773 | tty_unregister_device(driver, i); |
3774 | } | |
3775 | p = driver->ttys; | |
3776 | proc_tty_unregister_driver(driver); | |
3777 | driver->ttys = NULL; | |
3778 | driver->termios = driver->termios_locked = NULL; | |
3779 | kfree(p); | |
3780 | cdev_del(&driver->cdev); | |
3781 | return 0; | |
3782 | } | |
1da177e4 LT |
3783 | EXPORT_SYMBOL(tty_unregister_driver); |
3784 | ||
24ec839c PZ |
3785 | dev_t tty_devnum(struct tty_struct *tty) |
3786 | { | |
3787 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
3788 | } | |
3789 | EXPORT_SYMBOL(tty_devnum); | |
3790 | ||
3791 | void proc_clear_tty(struct task_struct *p) | |
3792 | { | |
3793 | spin_lock_irq(&p->sighand->siglock); | |
3794 | p->signal->tty = NULL; | |
3795 | spin_unlock_irq(&p->sighand->siglock); | |
3796 | } | |
3797 | EXPORT_SYMBOL(proc_clear_tty); | |
3798 | ||
cdc62330 | 3799 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
3800 | { |
3801 | if (tty) { | |
1ec320af | 3802 | tty->session = process_session(tsk); |
24ec839c PZ |
3803 | tty->pgrp = process_group(tsk); |
3804 | } | |
3805 | tsk->signal->tty = tty; | |
3806 | tsk->signal->tty_old_pgrp = 0; | |
3807 | } | |
3808 | ||
3809 | void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) | |
3810 | { | |
3811 | spin_lock_irq(&tsk->sighand->siglock); | |
3812 | __proc_set_tty(tsk, tty); | |
3813 | spin_unlock_irq(&tsk->sighand->siglock); | |
3814 | } | |
3815 | ||
3816 | struct tty_struct *get_current_tty(void) | |
3817 | { | |
3818 | struct tty_struct *tty; | |
3819 | WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); | |
3820 | tty = current->signal->tty; | |
3821 | /* | |
3822 | * session->tty can be changed/cleared from under us, make sure we | |
3823 | * issue the load. The obtained pointer, when not NULL, is valid as | |
3824 | * long as we hold tty_mutex. | |
3825 | */ | |
3826 | barrier(); | |
3827 | return tty; | |
3828 | } | |
a311f743 | 3829 | EXPORT_SYMBOL_GPL(get_current_tty); |
1da177e4 LT |
3830 | |
3831 | /* | |
3832 | * Initialize the console device. This is called *early*, so | |
3833 | * we can't necessarily depend on lots of kernel help here. | |
3834 | * Just do some early initializations, and do the complex setup | |
3835 | * later. | |
3836 | */ | |
3837 | void __init console_init(void) | |
3838 | { | |
3839 | initcall_t *call; | |
3840 | ||
3841 | /* Setup the default TTY line discipline. */ | |
3842 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); | |
3843 | ||
3844 | /* | |
3845 | * set up the console device so that later boot sequences can | |
3846 | * inform about problems etc.. | |
3847 | */ | |
3848 | #ifdef CONFIG_EARLY_PRINTK | |
3849 | disable_early_printk(); | |
1da177e4 LT |
3850 | #endif |
3851 | call = __con_initcall_start; | |
3852 | while (call < __con_initcall_end) { | |
3853 | (*call)(); | |
3854 | call++; | |
3855 | } | |
3856 | } | |
3857 | ||
3858 | #ifdef CONFIG_VT | |
3859 | extern int vty_init(void); | |
3860 | #endif | |
3861 | ||
3862 | static int __init tty_class_init(void) | |
3863 | { | |
7fe845d1 | 3864 | tty_class = class_create(THIS_MODULE, "tty"); |
1da177e4 LT |
3865 | if (IS_ERR(tty_class)) |
3866 | return PTR_ERR(tty_class); | |
3867 | return 0; | |
3868 | } | |
3869 | ||
3870 | postcore_initcall(tty_class_init); | |
3871 | ||
3872 | /* 3/2004 jmc: why do these devices exist? */ | |
3873 | ||
3874 | static struct cdev tty_cdev, console_cdev; | |
3875 | #ifdef CONFIG_UNIX98_PTYS | |
3876 | static struct cdev ptmx_cdev; | |
3877 | #endif | |
3878 | #ifdef CONFIG_VT | |
3879 | static struct cdev vc0_cdev; | |
3880 | #endif | |
3881 | ||
3882 | /* | |
3883 | * Ok, now we can initialize the rest of the tty devices and can count | |
3884 | * on memory allocations, interrupts etc.. | |
3885 | */ | |
3886 | static int __init tty_init(void) | |
3887 | { | |
3888 | cdev_init(&tty_cdev, &tty_fops); | |
3889 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
3890 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
3891 | panic("Couldn't register /dev/tty driver\n"); | |
01107d34 | 3892 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty"); |
1da177e4 LT |
3893 | |
3894 | cdev_init(&console_cdev, &console_fops); | |
3895 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
3896 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
3897 | panic("Couldn't register /dev/console driver\n"); | |
01107d34 | 3898 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console"); |
1da177e4 LT |
3899 | |
3900 | #ifdef CONFIG_UNIX98_PTYS | |
3901 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
3902 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
3903 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
3904 | panic("Couldn't register /dev/ptmx driver\n"); | |
01107d34 | 3905 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); |
1da177e4 LT |
3906 | #endif |
3907 | ||
3908 | #ifdef CONFIG_VT | |
3909 | cdev_init(&vc0_cdev, &console_fops); | |
3910 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || | |
3911 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) | |
3912 | panic("Couldn't register /dev/tty0 driver\n"); | |
01107d34 | 3913 | device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); |
1da177e4 LT |
3914 | |
3915 | vty_init(); | |
3916 | #endif | |
3917 | return 0; | |
3918 | } | |
3919 | module_init(tty_init); |