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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 | ||
1da177e4 LT |
144 | static void initialize_tty_struct(struct tty_struct *tty); |
145 | ||
146 | static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); | |
147 | static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); | |
148 | ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); | |
149 | static unsigned int tty_poll(struct file *, poll_table *); | |
150 | static int tty_open(struct inode *, struct file *); | |
151 | static int tty_release(struct inode *, struct file *); | |
152 | int tty_ioctl(struct inode * inode, struct file * file, | |
153 | unsigned int cmd, unsigned long arg); | |
154 | static int tty_fasync(int fd, struct file * filp, int on); | |
d5698c28 | 155 | static void release_tty(struct tty_struct *tty, int idx); |
2a65f1d9 | 156 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
98a27ba4 | 157 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
1da177e4 | 158 | |
af9b897e AC |
159 | /** |
160 | * alloc_tty_struct - allocate a tty object | |
161 | * | |
162 | * Return a new empty tty structure. The data fields have not | |
163 | * been initialized in any way but has been zeroed | |
164 | * | |
165 | * Locking: none | |
af9b897e | 166 | */ |
1da177e4 LT |
167 | |
168 | static struct tty_struct *alloc_tty_struct(void) | |
169 | { | |
1266b1e1 | 170 | return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); |
1da177e4 LT |
171 | } |
172 | ||
33f0f88f AC |
173 | static void tty_buffer_free_all(struct tty_struct *); |
174 | ||
af9b897e AC |
175 | /** |
176 | * free_tty_struct - free a disused tty | |
177 | * @tty: tty struct to free | |
178 | * | |
179 | * Free the write buffers, tty queue and tty memory itself. | |
180 | * | |
181 | * Locking: none. Must be called after tty is definitely unused | |
182 | */ | |
183 | ||
1da177e4 LT |
184 | static inline void free_tty_struct(struct tty_struct *tty) |
185 | { | |
186 | kfree(tty->write_buf); | |
33f0f88f | 187 | tty_buffer_free_all(tty); |
1da177e4 LT |
188 | kfree(tty); |
189 | } | |
190 | ||
191 | #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) | |
192 | ||
af9b897e AC |
193 | /** |
194 | * tty_name - return tty naming | |
195 | * @tty: tty structure | |
196 | * @buf: buffer for output | |
197 | * | |
198 | * Convert a tty structure into a name. The name reflects the kernel | |
199 | * naming policy and if udev is in use may not reflect user space | |
200 | * | |
201 | * Locking: none | |
202 | */ | |
203 | ||
1da177e4 LT |
204 | char *tty_name(struct tty_struct *tty, char *buf) |
205 | { | |
206 | if (!tty) /* Hmm. NULL pointer. That's fun. */ | |
207 | strcpy(buf, "NULL tty"); | |
208 | else | |
209 | strcpy(buf, tty->name); | |
210 | return buf; | |
211 | } | |
212 | ||
213 | EXPORT_SYMBOL(tty_name); | |
214 | ||
d769a669 | 215 | int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, |
1da177e4 LT |
216 | const char *routine) |
217 | { | |
218 | #ifdef TTY_PARANOIA_CHECK | |
219 | if (!tty) { | |
220 | printk(KERN_WARNING | |
221 | "null TTY for (%d:%d) in %s\n", | |
222 | imajor(inode), iminor(inode), routine); | |
223 | return 1; | |
224 | } | |
225 | if (tty->magic != TTY_MAGIC) { | |
226 | printk(KERN_WARNING | |
227 | "bad magic number for tty struct (%d:%d) in %s\n", | |
228 | imajor(inode), iminor(inode), routine); | |
229 | return 1; | |
230 | } | |
231 | #endif | |
232 | return 0; | |
233 | } | |
234 | ||
235 | static int check_tty_count(struct tty_struct *tty, const char *routine) | |
236 | { | |
237 | #ifdef CHECK_TTY_COUNT | |
238 | struct list_head *p; | |
239 | int count = 0; | |
240 | ||
241 | file_list_lock(); | |
242 | list_for_each(p, &tty->tty_files) { | |
243 | count++; | |
244 | } | |
245 | file_list_unlock(); | |
246 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
247 | tty->driver->subtype == PTY_TYPE_SLAVE && | |
248 | tty->link && tty->link->count) | |
249 | count++; | |
250 | if (tty->count != count) { | |
251 | printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " | |
252 | "!= #fd's(%d) in %s\n", | |
253 | tty->name, tty->count, count, routine); | |
254 | return count; | |
24ec839c | 255 | } |
1da177e4 LT |
256 | #endif |
257 | return 0; | |
258 | } | |
259 | ||
33f0f88f AC |
260 | /* |
261 | * Tty buffer allocation management | |
262 | */ | |
263 | ||
af9b897e AC |
264 | /** |
265 | * tty_buffer_free_all - free buffers used by a tty | |
266 | * @tty: tty to free from | |
267 | * | |
268 | * Remove all the buffers pending on a tty whether queued with data | |
269 | * or in the free ring. Must be called when the tty is no longer in use | |
270 | * | |
271 | * Locking: none | |
272 | */ | |
273 | ||
33f0f88f AC |
274 | static void tty_buffer_free_all(struct tty_struct *tty) |
275 | { | |
276 | struct tty_buffer *thead; | |
277 | while((thead = tty->buf.head) != NULL) { | |
278 | tty->buf.head = thead->next; | |
279 | kfree(thead); | |
280 | } | |
281 | while((thead = tty->buf.free) != NULL) { | |
282 | tty->buf.free = thead->next; | |
283 | kfree(thead); | |
284 | } | |
285 | tty->buf.tail = NULL; | |
01da5fd8 | 286 | tty->buf.memory_used = 0; |
33f0f88f AC |
287 | } |
288 | ||
01da5fd8 AC |
289 | /** |
290 | * tty_buffer_init - prepare a tty buffer structure | |
291 | * @tty: tty to initialise | |
292 | * | |
293 | * Set up the initial state of the buffer management for a tty device. | |
294 | * Must be called before the other tty buffer functions are used. | |
295 | * | |
296 | * Locking: none | |
297 | */ | |
298 | ||
33f0f88f AC |
299 | static void tty_buffer_init(struct tty_struct *tty) |
300 | { | |
808249ce | 301 | spin_lock_init(&tty->buf.lock); |
33f0f88f AC |
302 | tty->buf.head = NULL; |
303 | tty->buf.tail = NULL; | |
304 | tty->buf.free = NULL; | |
01da5fd8 | 305 | tty->buf.memory_used = 0; |
33f0f88f AC |
306 | } |
307 | ||
01da5fd8 AC |
308 | /** |
309 | * tty_buffer_alloc - allocate a tty buffer | |
310 | * @tty: tty device | |
311 | * @size: desired size (characters) | |
312 | * | |
313 | * Allocate a new tty buffer to hold the desired number of characters. | |
314 | * Return NULL if out of memory or the allocation would exceed the | |
315 | * per device queue | |
316 | * | |
317 | * Locking: Caller must hold tty->buf.lock | |
318 | */ | |
319 | ||
320 | static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) | |
33f0f88f | 321 | { |
01da5fd8 AC |
322 | struct tty_buffer *p; |
323 | ||
324 | if (tty->buf.memory_used + size > 65536) | |
325 | return NULL; | |
326 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); | |
33f0f88f AC |
327 | if(p == NULL) |
328 | return NULL; | |
329 | p->used = 0; | |
330 | p->size = size; | |
331 | p->next = NULL; | |
8977d929 PF |
332 | p->commit = 0; |
333 | p->read = 0; | |
33f0f88f AC |
334 | p->char_buf_ptr = (char *)(p->data); |
335 | p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; | |
01da5fd8 | 336 | tty->buf.memory_used += size; |
33f0f88f AC |
337 | return p; |
338 | } | |
339 | ||
01da5fd8 AC |
340 | /** |
341 | * tty_buffer_free - free a tty buffer | |
342 | * @tty: tty owning the buffer | |
343 | * @b: the buffer to free | |
344 | * | |
345 | * Free a tty buffer, or add it to the free list according to our | |
346 | * internal strategy | |
347 | * | |
348 | * Locking: Caller must hold tty->buf.lock | |
349 | */ | |
33f0f88f AC |
350 | |
351 | static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) | |
352 | { | |
353 | /* Dumb strategy for now - should keep some stats */ | |
01da5fd8 AC |
354 | tty->buf.memory_used -= b->size; |
355 | WARN_ON(tty->buf.memory_used < 0); | |
356 | ||
33f0f88f AC |
357 | if(b->size >= 512) |
358 | kfree(b); | |
359 | else { | |
360 | b->next = tty->buf.free; | |
361 | tty->buf.free = b; | |
362 | } | |
363 | } | |
364 | ||
01da5fd8 AC |
365 | /** |
366 | * tty_buffer_find - find a free tty buffer | |
367 | * @tty: tty owning the buffer | |
368 | * @size: characters wanted | |
369 | * | |
370 | * Locate an existing suitable tty buffer or if we are lacking one then | |
371 | * allocate a new one. We round our buffers off in 256 character chunks | |
372 | * to get better allocation behaviour. | |
373 | * | |
374 | * Locking: Caller must hold tty->buf.lock | |
375 | */ | |
376 | ||
33f0f88f AC |
377 | static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) |
378 | { | |
379 | struct tty_buffer **tbh = &tty->buf.free; | |
380 | while((*tbh) != NULL) { | |
381 | struct tty_buffer *t = *tbh; | |
382 | if(t->size >= size) { | |
383 | *tbh = t->next; | |
384 | t->next = NULL; | |
385 | t->used = 0; | |
8977d929 PF |
386 | t->commit = 0; |
387 | t->read = 0; | |
01da5fd8 | 388 | tty->buf.memory_used += t->size; |
33f0f88f AC |
389 | return t; |
390 | } | |
391 | tbh = &((*tbh)->next); | |
392 | } | |
393 | /* Round the buffer size out */ | |
394 | size = (size + 0xFF) & ~ 0xFF; | |
01da5fd8 | 395 | return tty_buffer_alloc(tty, size); |
33f0f88f AC |
396 | /* Should possibly check if this fails for the largest buffer we |
397 | have queued and recycle that ? */ | |
398 | } | |
399 | ||
01da5fd8 AC |
400 | /** |
401 | * tty_buffer_request_room - grow tty buffer if needed | |
402 | * @tty: tty structure | |
403 | * @size: size desired | |
404 | * | |
405 | * Make at least size bytes of linear space available for the tty | |
406 | * buffer. If we fail return the size we managed to find. | |
407 | * | |
408 | * Locking: Takes tty->buf.lock | |
409 | */ | |
33f0f88f AC |
410 | int tty_buffer_request_room(struct tty_struct *tty, size_t size) |
411 | { | |
808249ce PF |
412 | struct tty_buffer *b, *n; |
413 | int left; | |
414 | unsigned long flags; | |
415 | ||
416 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33f0f88f AC |
417 | |
418 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to | |
419 | remove this conditional if its worth it. This would be invisible | |
420 | to the callers */ | |
33b37a33 | 421 | if ((b = tty->buf.tail) != NULL) |
33f0f88f | 422 | left = b->size - b->used; |
33b37a33 | 423 | else |
808249ce PF |
424 | left = 0; |
425 | ||
426 | if (left < size) { | |
427 | /* This is the slow path - looking for new buffers to use */ | |
428 | if ((n = tty_buffer_find(tty, size)) != NULL) { | |
429 | if (b != NULL) { | |
430 | b->next = n; | |
8977d929 | 431 | b->commit = b->used; |
808249ce PF |
432 | } else |
433 | tty->buf.head = n; | |
434 | tty->buf.tail = n; | |
808249ce PF |
435 | } else |
436 | size = left; | |
437 | } | |
438 | ||
439 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
33f0f88f AC |
440 | return size; |
441 | } | |
33f0f88f AC |
442 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
443 | ||
af9b897e AC |
444 | /** |
445 | * tty_insert_flip_string - Add characters to the tty buffer | |
446 | * @tty: tty structure | |
447 | * @chars: characters | |
448 | * @size: size | |
449 | * | |
450 | * Queue a series of bytes to the tty buffering. All the characters | |
451 | * passed are marked as without error. Returns the number added. | |
452 | * | |
453 | * Locking: Called functions may take tty->buf.lock | |
454 | */ | |
455 | ||
e1a25090 AM |
456 | int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, |
457 | size_t size) | |
33f0f88f AC |
458 | { |
459 | int copied = 0; | |
460 | do { | |
461 | int space = tty_buffer_request_room(tty, size - copied); | |
462 | struct tty_buffer *tb = tty->buf.tail; | |
463 | /* If there is no space then tb may be NULL */ | |
464 | if(unlikely(space == 0)) | |
465 | break; | |
466 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
467 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
468 | tb->used += space; | |
469 | copied += space; | |
470 | chars += space; | |
527063ba AD |
471 | /* There is a small chance that we need to split the data over |
472 | several buffers. If this is the case we must loop */ | |
473 | } while (unlikely(size > copied)); | |
33f0f88f AC |
474 | return copied; |
475 | } | |
ee37df78 | 476 | EXPORT_SYMBOL(tty_insert_flip_string); |
33f0f88f | 477 | |
af9b897e AC |
478 | /** |
479 | * tty_insert_flip_string_flags - Add characters to the tty buffer | |
480 | * @tty: tty structure | |
481 | * @chars: characters | |
482 | * @flags: flag bytes | |
483 | * @size: size | |
484 | * | |
485 | * Queue a series of bytes to the tty buffering. For each character | |
486 | * the flags array indicates the status of the character. Returns the | |
487 | * number added. | |
488 | * | |
489 | * Locking: Called functions may take tty->buf.lock | |
490 | */ | |
491 | ||
e1a25090 AM |
492 | int tty_insert_flip_string_flags(struct tty_struct *tty, |
493 | const unsigned char *chars, const char *flags, size_t size) | |
33f0f88f AC |
494 | { |
495 | int copied = 0; | |
496 | do { | |
497 | int space = tty_buffer_request_room(tty, size - copied); | |
498 | struct tty_buffer *tb = tty->buf.tail; | |
499 | /* If there is no space then tb may be NULL */ | |
500 | if(unlikely(space == 0)) | |
501 | break; | |
502 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
503 | memcpy(tb->flag_buf_ptr + tb->used, flags, space); | |
504 | tb->used += space; | |
505 | copied += space; | |
506 | chars += space; | |
507 | flags += space; | |
527063ba AD |
508 | /* There is a small chance that we need to split the data over |
509 | several buffers. If this is the case we must loop */ | |
510 | } while (unlikely(size > copied)); | |
33f0f88f AC |
511 | return copied; |
512 | } | |
ff4547f4 | 513 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
33f0f88f | 514 | |
af9b897e AC |
515 | /** |
516 | * tty_schedule_flip - push characters to ldisc | |
517 | * @tty: tty to push from | |
518 | * | |
519 | * Takes any pending buffers and transfers their ownership to the | |
520 | * ldisc side of the queue. It then schedules those characters for | |
521 | * processing by the line discipline. | |
522 | * | |
523 | * Locking: Takes tty->buf.lock | |
524 | */ | |
525 | ||
e1a25090 AM |
526 | void tty_schedule_flip(struct tty_struct *tty) |
527 | { | |
528 | unsigned long flags; | |
529 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 530 | if (tty->buf.tail != NULL) |
e1a25090 | 531 | tty->buf.tail->commit = tty->buf.tail->used; |
e1a25090 AM |
532 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
533 | schedule_delayed_work(&tty->buf.work, 1); | |
534 | } | |
535 | EXPORT_SYMBOL(tty_schedule_flip); | |
33f0f88f | 536 | |
af9b897e AC |
537 | /** |
538 | * tty_prepare_flip_string - make room for characters | |
539 | * @tty: tty | |
540 | * @chars: return pointer for character write area | |
541 | * @size: desired size | |
542 | * | |
33f0f88f AC |
543 | * Prepare a block of space in the buffer for data. Returns the length |
544 | * available and buffer pointer to the space which is now allocated and | |
545 | * accounted for as ready for normal characters. This is used for drivers | |
546 | * that need their own block copy routines into the buffer. There is no | |
547 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
548 | * |
549 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
550 | */ |
551 | ||
552 | int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size) | |
553 | { | |
554 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
555 | if (likely(space)) { |
556 | struct tty_buffer *tb = tty->buf.tail; | |
557 | *chars = tb->char_buf_ptr + tb->used; | |
558 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
559 | tb->used += space; | |
560 | } | |
33f0f88f AC |
561 | return space; |
562 | } | |
563 | ||
564 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); | |
565 | ||
af9b897e AC |
566 | /** |
567 | * tty_prepare_flip_string_flags - make room for characters | |
568 | * @tty: tty | |
569 | * @chars: return pointer for character write area | |
570 | * @flags: return pointer for status flag write area | |
571 | * @size: desired size | |
572 | * | |
33f0f88f AC |
573 | * Prepare a block of space in the buffer for data. Returns the length |
574 | * available and buffer pointer to the space which is now allocated and | |
575 | * accounted for as ready for characters. This is used for drivers | |
576 | * that need their own block copy routines into the buffer. There is no | |
577 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
578 | * |
579 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
580 | */ |
581 | ||
582 | int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size) | |
583 | { | |
584 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
585 | if (likely(space)) { |
586 | struct tty_buffer *tb = tty->buf.tail; | |
587 | *chars = tb->char_buf_ptr + tb->used; | |
588 | *flags = tb->flag_buf_ptr + tb->used; | |
589 | tb->used += space; | |
590 | } | |
33f0f88f AC |
591 | return space; |
592 | } | |
593 | ||
594 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); | |
595 | ||
596 | ||
597 | ||
af9b897e AC |
598 | /** |
599 | * tty_set_termios_ldisc - set ldisc field | |
600 | * @tty: tty structure | |
601 | * @num: line discipline number | |
602 | * | |
1da177e4 LT |
603 | * This is probably overkill for real world processors but |
604 | * they are not on hot paths so a little discipline won't do | |
605 | * any harm. | |
af9b897e | 606 | * |
24ec839c | 607 | * Locking: takes termios_mutex |
1da177e4 LT |
608 | */ |
609 | ||
610 | static void tty_set_termios_ldisc(struct tty_struct *tty, int num) | |
611 | { | |
5785c95b | 612 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 613 | tty->termios->c_line = num; |
5785c95b | 614 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
615 | } |
616 | ||
617 | /* | |
618 | * This guards the refcounted line discipline lists. The lock | |
619 | * must be taken with irqs off because there are hangup path | |
620 | * callers who will do ldisc lookups and cannot sleep. | |
621 | */ | |
622 | ||
623 | static DEFINE_SPINLOCK(tty_ldisc_lock); | |
624 | static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); | |
bfb07599 | 625 | static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */ |
1da177e4 | 626 | |
af9b897e AC |
627 | /** |
628 | * tty_register_ldisc - install a line discipline | |
629 | * @disc: ldisc number | |
630 | * @new_ldisc: pointer to the ldisc object | |
631 | * | |
632 | * Installs a new line discipline into the kernel. The discipline | |
633 | * is set up as unreferenced and then made available to the kernel | |
634 | * from this point onwards. | |
635 | * | |
636 | * Locking: | |
637 | * takes tty_ldisc_lock to guard against ldisc races | |
638 | */ | |
639 | ||
1da177e4 LT |
640 | int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) |
641 | { | |
642 | unsigned long flags; | |
643 | int ret = 0; | |
644 | ||
645 | if (disc < N_TTY || disc >= NR_LDISCS) | |
646 | return -EINVAL; | |
647 | ||
648 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
bfb07599 AD |
649 | tty_ldiscs[disc] = *new_ldisc; |
650 | tty_ldiscs[disc].num = disc; | |
651 | tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; | |
652 | tty_ldiscs[disc].refcount = 0; | |
1da177e4 LT |
653 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
654 | ||
655 | return ret; | |
656 | } | |
1da177e4 LT |
657 | EXPORT_SYMBOL(tty_register_ldisc); |
658 | ||
af9b897e AC |
659 | /** |
660 | * tty_unregister_ldisc - unload a line discipline | |
661 | * @disc: ldisc number | |
662 | * @new_ldisc: pointer to the ldisc object | |
663 | * | |
664 | * Remove a line discipline from the kernel providing it is not | |
665 | * currently in use. | |
666 | * | |
667 | * Locking: | |
668 | * takes tty_ldisc_lock to guard against ldisc races | |
669 | */ | |
670 | ||
bfb07599 AD |
671 | int tty_unregister_ldisc(int disc) |
672 | { | |
673 | unsigned long flags; | |
674 | int ret = 0; | |
675 | ||
676 | if (disc < N_TTY || disc >= NR_LDISCS) | |
677 | return -EINVAL; | |
678 | ||
679 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
680 | if (tty_ldiscs[disc].refcount) | |
681 | ret = -EBUSY; | |
682 | else | |
683 | tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; | |
684 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
685 | ||
686 | return ret; | |
687 | } | |
688 | EXPORT_SYMBOL(tty_unregister_ldisc); | |
689 | ||
af9b897e AC |
690 | /** |
691 | * tty_ldisc_get - take a reference to an ldisc | |
692 | * @disc: ldisc number | |
693 | * | |
694 | * Takes a reference to a line discipline. Deals with refcounts and | |
695 | * module locking counts. Returns NULL if the discipline is not available. | |
696 | * Returns a pointer to the discipline and bumps the ref count if it is | |
697 | * available | |
698 | * | |
699 | * Locking: | |
700 | * takes tty_ldisc_lock to guard against ldisc races | |
701 | */ | |
702 | ||
1da177e4 LT |
703 | struct tty_ldisc *tty_ldisc_get(int disc) |
704 | { | |
705 | unsigned long flags; | |
706 | struct tty_ldisc *ld; | |
707 | ||
708 | if (disc < N_TTY || disc >= NR_LDISCS) | |
709 | return NULL; | |
710 | ||
711 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
712 | ||
713 | ld = &tty_ldiscs[disc]; | |
714 | /* Check the entry is defined */ | |
715 | if(ld->flags & LDISC_FLAG_DEFINED) | |
716 | { | |
717 | /* If the module is being unloaded we can't use it */ | |
718 | if (!try_module_get(ld->owner)) | |
719 | ld = NULL; | |
720 | else /* lock it */ | |
721 | ld->refcount++; | |
722 | } | |
723 | else | |
724 | ld = NULL; | |
725 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
726 | return ld; | |
727 | } | |
728 | ||
729 | EXPORT_SYMBOL_GPL(tty_ldisc_get); | |
730 | ||
af9b897e AC |
731 | /** |
732 | * tty_ldisc_put - drop ldisc reference | |
733 | * @disc: ldisc number | |
734 | * | |
735 | * Drop a reference to a line discipline. Manage refcounts and | |
736 | * module usage counts | |
737 | * | |
738 | * Locking: | |
739 | * takes tty_ldisc_lock to guard against ldisc races | |
740 | */ | |
741 | ||
1da177e4 LT |
742 | void tty_ldisc_put(int disc) |
743 | { | |
744 | struct tty_ldisc *ld; | |
745 | unsigned long flags; | |
746 | ||
56ee4827 | 747 | BUG_ON(disc < N_TTY || disc >= NR_LDISCS); |
1da177e4 LT |
748 | |
749 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
750 | ld = &tty_ldiscs[disc]; | |
56ee4827 ES |
751 | BUG_ON(ld->refcount == 0); |
752 | ld->refcount--; | |
1da177e4 LT |
753 | module_put(ld->owner); |
754 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
755 | } | |
756 | ||
757 | EXPORT_SYMBOL_GPL(tty_ldisc_put); | |
758 | ||
af9b897e AC |
759 | /** |
760 | * tty_ldisc_assign - set ldisc on a tty | |
761 | * @tty: tty to assign | |
762 | * @ld: line discipline | |
763 | * | |
764 | * Install an instance of a line discipline into a tty structure. The | |
765 | * ldisc must have a reference count above zero to ensure it remains/ | |
766 | * The tty instance refcount starts at zero. | |
767 | * | |
768 | * Locking: | |
769 | * Caller must hold references | |
770 | */ | |
771 | ||
1da177e4 LT |
772 | static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) |
773 | { | |
774 | tty->ldisc = *ld; | |
775 | tty->ldisc.refcount = 0; | |
776 | } | |
777 | ||
778 | /** | |
779 | * tty_ldisc_try - internal helper | |
780 | * @tty: the tty | |
781 | * | |
782 | * Make a single attempt to grab and bump the refcount on | |
783 | * the tty ldisc. Return 0 on failure or 1 on success. This is | |
784 | * used to implement both the waiting and non waiting versions | |
785 | * of tty_ldisc_ref | |
af9b897e AC |
786 | * |
787 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
788 | */ |
789 | ||
790 | static int tty_ldisc_try(struct tty_struct *tty) | |
791 | { | |
792 | unsigned long flags; | |
793 | struct tty_ldisc *ld; | |
794 | int ret = 0; | |
795 | ||
796 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
797 | ld = &tty->ldisc; | |
798 | if(test_bit(TTY_LDISC, &tty->flags)) | |
799 | { | |
800 | ld->refcount++; | |
801 | ret = 1; | |
802 | } | |
803 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
804 | return ret; | |
805 | } | |
806 | ||
807 | /** | |
808 | * tty_ldisc_ref_wait - wait for the tty ldisc | |
809 | * @tty: tty device | |
810 | * | |
811 | * Dereference the line discipline for the terminal and take a | |
812 | * reference to it. If the line discipline is in flux then | |
813 | * wait patiently until it changes. | |
814 | * | |
815 | * Note: Must not be called from an IRQ/timer context. The caller | |
816 | * must also be careful not to hold other locks that will deadlock | |
817 | * against a discipline change, such as an existing ldisc reference | |
818 | * (which we check for) | |
af9b897e AC |
819 | * |
820 | * Locking: call functions take tty_ldisc_lock | |
1da177e4 LT |
821 | */ |
822 | ||
823 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) | |
824 | { | |
825 | /* wait_event is a macro */ | |
826 | wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); | |
827 | if(tty->ldisc.refcount == 0) | |
828 | printk(KERN_ERR "tty_ldisc_ref_wait\n"); | |
829 | return &tty->ldisc; | |
830 | } | |
831 | ||
832 | EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); | |
833 | ||
834 | /** | |
835 | * tty_ldisc_ref - get the tty ldisc | |
836 | * @tty: tty device | |
837 | * | |
838 | * Dereference the line discipline for the terminal and take a | |
839 | * reference to it. If the line discipline is in flux then | |
840 | * return NULL. Can be called from IRQ and timer functions. | |
af9b897e AC |
841 | * |
842 | * Locking: called functions take tty_ldisc_lock | |
1da177e4 LT |
843 | */ |
844 | ||
845 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) | |
846 | { | |
847 | if(tty_ldisc_try(tty)) | |
848 | return &tty->ldisc; | |
849 | return NULL; | |
850 | } | |
851 | ||
852 | EXPORT_SYMBOL_GPL(tty_ldisc_ref); | |
853 | ||
854 | /** | |
855 | * tty_ldisc_deref - free a tty ldisc reference | |
856 | * @ld: reference to free up | |
857 | * | |
858 | * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May | |
859 | * be called in IRQ context. | |
af9b897e AC |
860 | * |
861 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
862 | */ |
863 | ||
864 | void tty_ldisc_deref(struct tty_ldisc *ld) | |
865 | { | |
866 | unsigned long flags; | |
867 | ||
56ee4827 | 868 | BUG_ON(ld == NULL); |
1da177e4 LT |
869 | |
870 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
871 | if(ld->refcount == 0) | |
872 | printk(KERN_ERR "tty_ldisc_deref: no references.\n"); | |
873 | else | |
874 | ld->refcount--; | |
875 | if(ld->refcount == 0) | |
876 | wake_up(&tty_ldisc_wait); | |
877 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
878 | } | |
879 | ||
880 | EXPORT_SYMBOL_GPL(tty_ldisc_deref); | |
881 | ||
882 | /** | |
883 | * tty_ldisc_enable - allow ldisc use | |
884 | * @tty: terminal to activate ldisc on | |
885 | * | |
886 | * Set the TTY_LDISC flag when the line discipline can be called | |
887 | * again. Do neccessary wakeups for existing sleepers. | |
888 | * | |
889 | * Note: nobody should set this bit except via this function. Clearing | |
890 | * directly is allowed. | |
891 | */ | |
892 | ||
893 | static void tty_ldisc_enable(struct tty_struct *tty) | |
894 | { | |
895 | set_bit(TTY_LDISC, &tty->flags); | |
896 | wake_up(&tty_ldisc_wait); | |
897 | } | |
898 | ||
899 | /** | |
900 | * tty_set_ldisc - set line discipline | |
901 | * @tty: the terminal to set | |
902 | * @ldisc: the line discipline | |
903 | * | |
904 | * Set the discipline of a tty line. Must be called from a process | |
905 | * context. | |
af9b897e AC |
906 | * |
907 | * Locking: takes tty_ldisc_lock. | |
24ec839c | 908 | * called functions take termios_mutex |
1da177e4 LT |
909 | */ |
910 | ||
911 | static int tty_set_ldisc(struct tty_struct *tty, int ldisc) | |
912 | { | |
ff55fe20 JB |
913 | int retval = 0; |
914 | struct tty_ldisc o_ldisc; | |
1da177e4 LT |
915 | char buf[64]; |
916 | int work; | |
917 | unsigned long flags; | |
918 | struct tty_ldisc *ld; | |
ff55fe20 | 919 | struct tty_struct *o_tty; |
1da177e4 LT |
920 | |
921 | if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) | |
922 | return -EINVAL; | |
923 | ||
924 | restart: | |
925 | ||
1da177e4 LT |
926 | ld = tty_ldisc_get(ldisc); |
927 | /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ | |
928 | /* Cyrus Durgin <cider@speakeasy.org> */ | |
929 | if (ld == NULL) { | |
930 | request_module("tty-ldisc-%d", ldisc); | |
931 | ld = tty_ldisc_get(ldisc); | |
932 | } | |
933 | if (ld == NULL) | |
934 | return -EINVAL; | |
935 | ||
33f0f88f AC |
936 | /* |
937 | * No more input please, we are switching. The new ldisc | |
938 | * will update this value in the ldisc open function | |
939 | */ | |
940 | ||
941 | tty->receive_room = 0; | |
942 | ||
943 | /* | |
944 | * Problem: What do we do if this blocks ? | |
945 | */ | |
946 | ||
1da177e4 LT |
947 | tty_wait_until_sent(tty, 0); |
948 | ||
ff55fe20 JB |
949 | if (tty->ldisc.num == ldisc) { |
950 | tty_ldisc_put(ldisc); | |
951 | return 0; | |
952 | } | |
953 | ||
954 | o_ldisc = tty->ldisc; | |
955 | o_tty = tty->link; | |
956 | ||
1da177e4 LT |
957 | /* |
958 | * Make sure we don't change while someone holds a | |
959 | * reference to the line discipline. The TTY_LDISC bit | |
960 | * prevents anyone taking a reference once it is clear. | |
961 | * We need the lock to avoid racing reference takers. | |
962 | */ | |
ff55fe20 | 963 | |
1da177e4 | 964 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
ff55fe20 JB |
965 | if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { |
966 | if(tty->ldisc.refcount) { | |
967 | /* Free the new ldisc we grabbed. Must drop the lock | |
968 | first. */ | |
969 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
970 | tty_ldisc_put(ldisc); | |
971 | /* | |
972 | * There are several reasons we may be busy, including | |
973 | * random momentary I/O traffic. We must therefore | |
974 | * retry. We could distinguish between blocking ops | |
975 | * and retries if we made tty_ldisc_wait() smarter. That | |
976 | * is up for discussion. | |
977 | */ | |
978 | if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) | |
979 | return -ERESTARTSYS; | |
980 | goto restart; | |
981 | } | |
982 | if(o_tty && o_tty->ldisc.refcount) { | |
983 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
984 | tty_ldisc_put(ldisc); | |
985 | if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) | |
986 | return -ERESTARTSYS; | |
987 | goto restart; | |
988 | } | |
989 | } | |
990 | ||
991 | /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */ | |
992 | ||
993 | if (!test_bit(TTY_LDISC, &tty->flags)) { | |
1da177e4 LT |
994 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
995 | tty_ldisc_put(ldisc); | |
ff55fe20 JB |
996 | ld = tty_ldisc_ref_wait(tty); |
997 | tty_ldisc_deref(ld); | |
1da177e4 LT |
998 | goto restart; |
999 | } | |
ff55fe20 JB |
1000 | |
1001 | clear_bit(TTY_LDISC, &tty->flags); | |
817d6d3b | 1002 | if (o_tty) |
ff55fe20 | 1003 | clear_bit(TTY_LDISC, &o_tty->flags); |
1da177e4 | 1004 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
ff55fe20 | 1005 | |
1da177e4 LT |
1006 | /* |
1007 | * From this point on we know nobody has an ldisc | |
1008 | * usage reference, nor can they obtain one until | |
1009 | * we say so later on. | |
1010 | */ | |
ff55fe20 | 1011 | |
33f0f88f | 1012 | work = cancel_delayed_work(&tty->buf.work); |
1da177e4 | 1013 | /* |
33f0f88f | 1014 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 LT |
1015 | */ |
1016 | ||
1017 | flush_scheduled_work(); | |
1018 | /* Shutdown the current discipline. */ | |
1019 | if (tty->ldisc.close) | |
1020 | (tty->ldisc.close)(tty); | |
1021 | ||
1022 | /* Now set up the new line discipline. */ | |
1023 | tty_ldisc_assign(tty, ld); | |
1024 | tty_set_termios_ldisc(tty, ldisc); | |
1025 | if (tty->ldisc.open) | |
1026 | retval = (tty->ldisc.open)(tty); | |
1027 | if (retval < 0) { | |
1028 | tty_ldisc_put(ldisc); | |
1029 | /* There is an outstanding reference here so this is safe */ | |
1030 | tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); | |
1031 | tty_set_termios_ldisc(tty, tty->ldisc.num); | |
1032 | if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { | |
1033 | tty_ldisc_put(o_ldisc.num); | |
1034 | /* This driver is always present */ | |
1035 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
1036 | tty_set_termios_ldisc(tty, N_TTY); | |
1037 | if (tty->ldisc.open) { | |
1038 | int r = tty->ldisc.open(tty); | |
1039 | ||
1040 | if (r < 0) | |
1041 | panic("Couldn't open N_TTY ldisc for " | |
1042 | "%s --- error %d.", | |
1043 | tty_name(tty, buf), r); | |
1044 | } | |
1045 | } | |
1046 | } | |
1047 | /* At this point we hold a reference to the new ldisc and a | |
1048 | a reference to the old ldisc. If we ended up flipping back | |
1049 | to the existing ldisc we have two references to it */ | |
1050 | ||
1051 | if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) | |
1052 | tty->driver->set_ldisc(tty); | |
1053 | ||
1054 | tty_ldisc_put(o_ldisc.num); | |
1055 | ||
1056 | /* | |
1057 | * Allow ldisc referencing to occur as soon as the driver | |
1058 | * ldisc callback completes. | |
1059 | */ | |
1060 | ||
1061 | tty_ldisc_enable(tty); | |
ff55fe20 JB |
1062 | if (o_tty) |
1063 | tty_ldisc_enable(o_tty); | |
1da177e4 LT |
1064 | |
1065 | /* Restart it in case no characters kick it off. Safe if | |
1066 | already running */ | |
ff55fe20 | 1067 | if (work) |
33f0f88f | 1068 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
1069 | return retval; |
1070 | } | |
1071 | ||
af9b897e AC |
1072 | /** |
1073 | * get_tty_driver - find device of a tty | |
1074 | * @dev_t: device identifier | |
1075 | * @index: returns the index of the tty | |
1076 | * | |
1077 | * This routine returns a tty driver structure, given a device number | |
1078 | * and also passes back the index number. | |
1079 | * | |
1080 | * Locking: caller must hold tty_mutex | |
1da177e4 | 1081 | */ |
af9b897e | 1082 | |
1da177e4 LT |
1083 | static struct tty_driver *get_tty_driver(dev_t device, int *index) |
1084 | { | |
1085 | struct tty_driver *p; | |
1086 | ||
1087 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1088 | dev_t base = MKDEV(p->major, p->minor_start); | |
1089 | if (device < base || device >= base + p->num) | |
1090 | continue; | |
1091 | *index = device - base; | |
1092 | return p; | |
1093 | } | |
1094 | return NULL; | |
1095 | } | |
1096 | ||
af9b897e AC |
1097 | /** |
1098 | * tty_check_change - check for POSIX terminal changes | |
1099 | * @tty: tty to check | |
1100 | * | |
1101 | * If we try to write to, or set the state of, a terminal and we're | |
1102 | * not in the foreground, send a SIGTTOU. If the signal is blocked or | |
1103 | * ignored, go ahead and perform the operation. (POSIX 7.2) | |
1104 | * | |
1105 | * Locking: none | |
1da177e4 | 1106 | */ |
af9b897e | 1107 | |
1da177e4 LT |
1108 | int tty_check_change(struct tty_struct * tty) |
1109 | { | |
1110 | if (current->signal->tty != tty) | |
1111 | return 0; | |
ab521dc0 EB |
1112 | if (!tty->pgrp) { |
1113 | printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n"); | |
1da177e4 LT |
1114 | return 0; |
1115 | } | |
ab521dc0 | 1116 | if (task_pgrp(current) == tty->pgrp) |
1da177e4 LT |
1117 | return 0; |
1118 | if (is_ignored(SIGTTOU)) | |
1119 | return 0; | |
3e7cd6c4 | 1120 | if (is_current_pgrp_orphaned()) |
1da177e4 | 1121 | return -EIO; |
ab521dc0 | 1122 | (void) kill_pgrp(task_pgrp(current), SIGTTOU, 1); |
1da177e4 LT |
1123 | return -ERESTARTSYS; |
1124 | } | |
1125 | ||
1126 | EXPORT_SYMBOL(tty_check_change); | |
1127 | ||
1128 | static ssize_t hung_up_tty_read(struct file * file, char __user * buf, | |
1129 | size_t count, loff_t *ppos) | |
1130 | { | |
1131 | return 0; | |
1132 | } | |
1133 | ||
1134 | static ssize_t hung_up_tty_write(struct file * file, const char __user * buf, | |
1135 | size_t count, loff_t *ppos) | |
1136 | { | |
1137 | return -EIO; | |
1138 | } | |
1139 | ||
1140 | /* No kernel lock held - none needed ;) */ | |
1141 | static unsigned int hung_up_tty_poll(struct file * filp, poll_table * wait) | |
1142 | { | |
1143 | return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; | |
1144 | } | |
1145 | ||
1146 | static int hung_up_tty_ioctl(struct inode * inode, struct file * file, | |
1147 | unsigned int cmd, unsigned long arg) | |
1148 | { | |
1149 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1150 | } | |
1151 | ||
62322d25 | 1152 | static const struct file_operations tty_fops = { |
1da177e4 LT |
1153 | .llseek = no_llseek, |
1154 | .read = tty_read, | |
1155 | .write = tty_write, | |
1156 | .poll = tty_poll, | |
1157 | .ioctl = tty_ioctl, | |
1158 | .open = tty_open, | |
1159 | .release = tty_release, | |
1160 | .fasync = tty_fasync, | |
1161 | }; | |
1162 | ||
1163 | #ifdef CONFIG_UNIX98_PTYS | |
62322d25 | 1164 | static const struct file_operations ptmx_fops = { |
1da177e4 LT |
1165 | .llseek = no_llseek, |
1166 | .read = tty_read, | |
1167 | .write = tty_write, | |
1168 | .poll = tty_poll, | |
1169 | .ioctl = tty_ioctl, | |
1170 | .open = ptmx_open, | |
1171 | .release = tty_release, | |
1172 | .fasync = tty_fasync, | |
1173 | }; | |
1174 | #endif | |
1175 | ||
62322d25 | 1176 | static const struct file_operations console_fops = { |
1da177e4 LT |
1177 | .llseek = no_llseek, |
1178 | .read = tty_read, | |
1179 | .write = redirected_tty_write, | |
1180 | .poll = tty_poll, | |
1181 | .ioctl = tty_ioctl, | |
1182 | .open = tty_open, | |
1183 | .release = tty_release, | |
1184 | .fasync = tty_fasync, | |
1185 | }; | |
1186 | ||
62322d25 | 1187 | static const struct file_operations hung_up_tty_fops = { |
1da177e4 LT |
1188 | .llseek = no_llseek, |
1189 | .read = hung_up_tty_read, | |
1190 | .write = hung_up_tty_write, | |
1191 | .poll = hung_up_tty_poll, | |
1192 | .ioctl = hung_up_tty_ioctl, | |
1193 | .release = tty_release, | |
1194 | }; | |
1195 | ||
1196 | static DEFINE_SPINLOCK(redirect_lock); | |
1197 | static struct file *redirect; | |
1198 | ||
1199 | /** | |
1200 | * tty_wakeup - request more data | |
1201 | * @tty: terminal | |
1202 | * | |
1203 | * Internal and external helper for wakeups of tty. This function | |
1204 | * informs the line discipline if present that the driver is ready | |
1205 | * to receive more output data. | |
1206 | */ | |
1207 | ||
1208 | void tty_wakeup(struct tty_struct *tty) | |
1209 | { | |
1210 | struct tty_ldisc *ld; | |
1211 | ||
1212 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { | |
1213 | ld = tty_ldisc_ref(tty); | |
1214 | if(ld) { | |
1215 | if(ld->write_wakeup) | |
1216 | ld->write_wakeup(tty); | |
1217 | tty_ldisc_deref(ld); | |
1218 | } | |
1219 | } | |
1220 | wake_up_interruptible(&tty->write_wait); | |
1221 | } | |
1222 | ||
1223 | EXPORT_SYMBOL_GPL(tty_wakeup); | |
1224 | ||
1225 | /** | |
1226 | * tty_ldisc_flush - flush line discipline queue | |
1227 | * @tty: tty | |
1228 | * | |
1229 | * Flush the line discipline queue (if any) for this tty. If there | |
1230 | * is no line discipline active this is a no-op. | |
1231 | */ | |
1232 | ||
1233 | void tty_ldisc_flush(struct tty_struct *tty) | |
1234 | { | |
1235 | struct tty_ldisc *ld = tty_ldisc_ref(tty); | |
1236 | if(ld) { | |
1237 | if(ld->flush_buffer) | |
1238 | ld->flush_buffer(tty); | |
1239 | tty_ldisc_deref(ld); | |
1240 | } | |
1241 | } | |
1242 | ||
1243 | EXPORT_SYMBOL_GPL(tty_ldisc_flush); | |
edc6afc5 AC |
1244 | |
1245 | /** | |
1246 | * tty_reset_termios - reset terminal state | |
1247 | * @tty: tty to reset | |
1248 | * | |
1249 | * Restore a terminal to the driver default state | |
1250 | */ | |
1251 | ||
1252 | static void tty_reset_termios(struct tty_struct *tty) | |
1253 | { | |
1254 | mutex_lock(&tty->termios_mutex); | |
1255 | *tty->termios = tty->driver->init_termios; | |
1256 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
1257 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1258 | mutex_unlock(&tty->termios_mutex); | |
1259 | } | |
1da177e4 | 1260 | |
af9b897e AC |
1261 | /** |
1262 | * do_tty_hangup - actual handler for hangup events | |
65f27f38 | 1263 | * @work: tty device |
af9b897e AC |
1264 | * |
1265 | * This can be called by the "eventd" kernel thread. That is process | |
1266 | * synchronous but doesn't hold any locks, so we need to make sure we | |
1267 | * have the appropriate locks for what we're doing. | |
1268 | * | |
1269 | * The hangup event clears any pending redirections onto the hung up | |
1270 | * device. It ensures future writes will error and it does the needed | |
1271 | * line discipline hangup and signal delivery. The tty object itself | |
1272 | * remains intact. | |
1273 | * | |
1274 | * Locking: | |
1275 | * BKL | |
24ec839c PZ |
1276 | * redirect lock for undoing redirection |
1277 | * file list lock for manipulating list of ttys | |
1278 | * tty_ldisc_lock from called functions | |
1279 | * termios_mutex resetting termios data | |
1280 | * tasklist_lock to walk task list for hangup event | |
1281 | * ->siglock to protect ->signal/->sighand | |
1da177e4 | 1282 | */ |
65f27f38 | 1283 | static void do_tty_hangup(struct work_struct *work) |
1da177e4 | 1284 | { |
65f27f38 DH |
1285 | struct tty_struct *tty = |
1286 | container_of(work, struct tty_struct, hangup_work); | |
1da177e4 LT |
1287 | struct file * cons_filp = NULL; |
1288 | struct file *filp, *f = NULL; | |
1289 | struct task_struct *p; | |
1290 | struct tty_ldisc *ld; | |
1291 | int closecount = 0, n; | |
1292 | ||
1293 | if (!tty) | |
1294 | return; | |
1295 | ||
1296 | /* inuse_filps is protected by the single kernel lock */ | |
1297 | lock_kernel(); | |
1298 | ||
1299 | spin_lock(&redirect_lock); | |
1300 | if (redirect && redirect->private_data == tty) { | |
1301 | f = redirect; | |
1302 | redirect = NULL; | |
1303 | } | |
1304 | spin_unlock(&redirect_lock); | |
1305 | ||
1306 | check_tty_count(tty, "do_tty_hangup"); | |
1307 | file_list_lock(); | |
1308 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ | |
2f512016 | 1309 | list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { |
1da177e4 LT |
1310 | if (filp->f_op->write == redirected_tty_write) |
1311 | cons_filp = filp; | |
1312 | if (filp->f_op->write != tty_write) | |
1313 | continue; | |
1314 | closecount++; | |
1315 | tty_fasync(-1, filp, 0); /* can't block */ | |
1316 | filp->f_op = &hung_up_tty_fops; | |
1317 | } | |
1318 | file_list_unlock(); | |
1319 | ||
1320 | /* FIXME! What are the locking issues here? This may me overdoing things.. | |
1321 | * this question is especially important now that we've removed the irqlock. */ | |
1322 | ||
1323 | ld = tty_ldisc_ref(tty); | |
1324 | if(ld != NULL) /* We may have no line discipline at this point */ | |
1325 | { | |
1326 | if (ld->flush_buffer) | |
1327 | ld->flush_buffer(tty); | |
1328 | if (tty->driver->flush_buffer) | |
1329 | tty->driver->flush_buffer(tty); | |
1330 | if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && | |
1331 | ld->write_wakeup) | |
1332 | ld->write_wakeup(tty); | |
1333 | if (ld->hangup) | |
1334 | ld->hangup(tty); | |
1335 | } | |
1336 | ||
1337 | /* FIXME: Once we trust the LDISC code better we can wait here for | |
1338 | ldisc completion and fix the driver call race */ | |
1339 | ||
1340 | wake_up_interruptible(&tty->write_wait); | |
1341 | wake_up_interruptible(&tty->read_wait); | |
1342 | ||
1343 | /* | |
1344 | * Shutdown the current line discipline, and reset it to | |
1345 | * N_TTY. | |
1346 | */ | |
1347 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
edc6afc5 | 1348 | tty_reset_termios(tty); |
1da177e4 LT |
1349 | |
1350 | /* Defer ldisc switch */ | |
1351 | /* tty_deferred_ldisc_switch(N_TTY); | |
1352 | ||
1353 | This should get done automatically when the port closes and | |
1354 | tty_release is called */ | |
1355 | ||
1356 | read_lock(&tasklist_lock); | |
ab521dc0 EB |
1357 | if (tty->session) { |
1358 | do_each_pid_task(tty->session, PIDTYPE_SID, p) { | |
24ec839c | 1359 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
1360 | if (p->signal->tty == tty) |
1361 | p->signal->tty = NULL; | |
24ec839c PZ |
1362 | if (!p->signal->leader) { |
1363 | spin_unlock_irq(&p->sighand->siglock); | |
1da177e4 | 1364 | continue; |
24ec839c PZ |
1365 | } |
1366 | __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); | |
1367 | __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); | |
ab521dc0 EB |
1368 | put_pid(p->signal->tty_old_pgrp); /* A noop */ |
1369 | if (tty->pgrp) | |
1370 | p->signal->tty_old_pgrp = get_pid(tty->pgrp); | |
24ec839c | 1371 | spin_unlock_irq(&p->sighand->siglock); |
ab521dc0 | 1372 | } while_each_pid_task(tty->session, PIDTYPE_SID, p); |
1da177e4 LT |
1373 | } |
1374 | read_unlock(&tasklist_lock); | |
1375 | ||
1376 | tty->flags = 0; | |
d9c1e9a8 EB |
1377 | put_pid(tty->session); |
1378 | put_pid(tty->pgrp); | |
ab521dc0 EB |
1379 | tty->session = NULL; |
1380 | tty->pgrp = NULL; | |
1da177e4 LT |
1381 | tty->ctrl_status = 0; |
1382 | /* | |
1383 | * If one of the devices matches a console pointer, we | |
1384 | * cannot just call hangup() because that will cause | |
1385 | * tty->count and state->count to go out of sync. | |
1386 | * So we just call close() the right number of times. | |
1387 | */ | |
1388 | if (cons_filp) { | |
1389 | if (tty->driver->close) | |
1390 | for (n = 0; n < closecount; n++) | |
1391 | tty->driver->close(tty, cons_filp); | |
1392 | } else if (tty->driver->hangup) | |
1393 | (tty->driver->hangup)(tty); | |
1394 | ||
1395 | /* We don't want to have driver/ldisc interactions beyond | |
1396 | the ones we did here. The driver layer expects no | |
1397 | calls after ->hangup() from the ldisc side. However we | |
1398 | can't yet guarantee all that */ | |
1399 | ||
1400 | set_bit(TTY_HUPPED, &tty->flags); | |
1401 | if (ld) { | |
1402 | tty_ldisc_enable(tty); | |
1403 | tty_ldisc_deref(ld); | |
1404 | } | |
1405 | unlock_kernel(); | |
1406 | if (f) | |
1407 | fput(f); | |
1408 | } | |
1409 | ||
af9b897e AC |
1410 | /** |
1411 | * tty_hangup - trigger a hangup event | |
1412 | * @tty: tty to hangup | |
1413 | * | |
1414 | * A carrier loss (virtual or otherwise) has occurred on this like | |
1415 | * schedule a hangup sequence to run after this event. | |
1416 | */ | |
1417 | ||
1da177e4 LT |
1418 | void tty_hangup(struct tty_struct * tty) |
1419 | { | |
1420 | #ifdef TTY_DEBUG_HANGUP | |
1421 | char buf[64]; | |
1422 | ||
1423 | printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); | |
1424 | #endif | |
1425 | schedule_work(&tty->hangup_work); | |
1426 | } | |
1427 | ||
1428 | EXPORT_SYMBOL(tty_hangup); | |
1429 | ||
af9b897e AC |
1430 | /** |
1431 | * tty_vhangup - process vhangup | |
1432 | * @tty: tty to hangup | |
1433 | * | |
1434 | * The user has asked via system call for the terminal to be hung up. | |
1435 | * We do this synchronously so that when the syscall returns the process | |
1436 | * is complete. That guarantee is neccessary for security reasons. | |
1437 | */ | |
1438 | ||
1da177e4 LT |
1439 | void tty_vhangup(struct tty_struct * tty) |
1440 | { | |
1441 | #ifdef TTY_DEBUG_HANGUP | |
1442 | char buf[64]; | |
1443 | ||
1444 | printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); | |
1445 | #endif | |
65f27f38 | 1446 | do_tty_hangup(&tty->hangup_work); |
1da177e4 LT |
1447 | } |
1448 | EXPORT_SYMBOL(tty_vhangup); | |
1449 | ||
af9b897e AC |
1450 | /** |
1451 | * tty_hung_up_p - was tty hung up | |
1452 | * @filp: file pointer of tty | |
1453 | * | |
1454 | * Return true if the tty has been subject to a vhangup or a carrier | |
1455 | * loss | |
1456 | */ | |
1457 | ||
1da177e4 LT |
1458 | int tty_hung_up_p(struct file * filp) |
1459 | { | |
1460 | return (filp->f_op == &hung_up_tty_fops); | |
1461 | } | |
1462 | ||
1463 | EXPORT_SYMBOL(tty_hung_up_p); | |
1464 | ||
ab521dc0 | 1465 | static void session_clear_tty(struct pid *session) |
24ec839c PZ |
1466 | { |
1467 | struct task_struct *p; | |
ab521dc0 | 1468 | do_each_pid_task(session, PIDTYPE_SID, p) { |
24ec839c | 1469 | proc_clear_tty(p); |
ab521dc0 | 1470 | } while_each_pid_task(session, PIDTYPE_SID, p); |
24ec839c PZ |
1471 | } |
1472 | ||
af9b897e AC |
1473 | /** |
1474 | * disassociate_ctty - disconnect controlling tty | |
1475 | * @on_exit: true if exiting so need to "hang up" the session | |
1da177e4 | 1476 | * |
af9b897e AC |
1477 | * This function is typically called only by the session leader, when |
1478 | * it wants to disassociate itself from its controlling tty. | |
1479 | * | |
1480 | * It performs the following functions: | |
1da177e4 LT |
1481 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
1482 | * (2) Clears the tty from being controlling the session | |
1483 | * (3) Clears the controlling tty for all processes in the | |
1484 | * session group. | |
1485 | * | |
af9b897e AC |
1486 | * The argument on_exit is set to 1 if called when a process is |
1487 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. | |
1488 | * | |
24ec839c | 1489 | * Locking: |
af9b897e | 1490 | * BKL is taken for hysterical raisins |
24ec839c PZ |
1491 | * tty_mutex is taken to protect tty |
1492 | * ->siglock is taken to protect ->signal/->sighand | |
1493 | * tasklist_lock is taken to walk process list for sessions | |
1494 | * ->siglock is taken to protect ->signal/->sighand | |
1da177e4 | 1495 | */ |
af9b897e | 1496 | |
1da177e4 LT |
1497 | void disassociate_ctty(int on_exit) |
1498 | { | |
1499 | struct tty_struct *tty; | |
ab521dc0 | 1500 | struct pid *tty_pgrp = NULL; |
1da177e4 LT |
1501 | |
1502 | lock_kernel(); | |
1503 | ||
70522e12 | 1504 | mutex_lock(&tty_mutex); |
24ec839c | 1505 | tty = get_current_tty(); |
1da177e4 | 1506 | if (tty) { |
ab521dc0 | 1507 | tty_pgrp = get_pid(tty->pgrp); |
70522e12 | 1508 | mutex_unlock(&tty_mutex); |
24ec839c | 1509 | /* XXX: here we race, there is nothing protecting tty */ |
1da177e4 LT |
1510 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
1511 | tty_vhangup(tty); | |
680a9671 | 1512 | } else if (on_exit) { |
ab521dc0 | 1513 | struct pid *old_pgrp; |
680a9671 EB |
1514 | spin_lock_irq(¤t->sighand->siglock); |
1515 | old_pgrp = current->signal->tty_old_pgrp; | |
ab521dc0 | 1516 | current->signal->tty_old_pgrp = NULL; |
680a9671 | 1517 | spin_unlock_irq(¤t->sighand->siglock); |
24ec839c | 1518 | if (old_pgrp) { |
ab521dc0 EB |
1519 | kill_pgrp(old_pgrp, SIGHUP, on_exit); |
1520 | kill_pgrp(old_pgrp, SIGCONT, on_exit); | |
1521 | put_pid(old_pgrp); | |
1da177e4 | 1522 | } |
70522e12 | 1523 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
1524 | unlock_kernel(); |
1525 | return; | |
1526 | } | |
ab521dc0 EB |
1527 | if (tty_pgrp) { |
1528 | kill_pgrp(tty_pgrp, SIGHUP, on_exit); | |
1da177e4 | 1529 | if (!on_exit) |
ab521dc0 EB |
1530 | kill_pgrp(tty_pgrp, SIGCONT, on_exit); |
1531 | put_pid(tty_pgrp); | |
1da177e4 LT |
1532 | } |
1533 | ||
24ec839c | 1534 | spin_lock_irq(¤t->sighand->siglock); |
2a65f1d9 | 1535 | put_pid(current->signal->tty_old_pgrp); |
23cac8de | 1536 | current->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
1537 | spin_unlock_irq(¤t->sighand->siglock); |
1538 | ||
1539 | mutex_lock(&tty_mutex); | |
1540 | /* It is possible that do_tty_hangup has free'd this tty */ | |
1541 | tty = get_current_tty(); | |
1542 | if (tty) { | |
ab521dc0 EB |
1543 | put_pid(tty->session); |
1544 | put_pid(tty->pgrp); | |
1545 | tty->session = NULL; | |
1546 | tty->pgrp = NULL; | |
24ec839c PZ |
1547 | } else { |
1548 | #ifdef TTY_DEBUG_HANGUP | |
1549 | printk(KERN_DEBUG "error attempted to write to tty [0x%p]" | |
1550 | " = NULL", tty); | |
1551 | #endif | |
1552 | } | |
1553 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
1554 | |
1555 | /* Now clear signal->tty under the lock */ | |
1556 | read_lock(&tasklist_lock); | |
ab521dc0 | 1557 | session_clear_tty(task_session(current)); |
1da177e4 | 1558 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1559 | unlock_kernel(); |
1560 | } | |
1561 | ||
98a27ba4 EB |
1562 | /** |
1563 | * | |
1564 | * no_tty - Ensure the current process does not have a controlling tty | |
1565 | */ | |
1566 | void no_tty(void) | |
1567 | { | |
1568 | struct task_struct *tsk = current; | |
1569 | if (tsk->signal->leader) | |
1570 | disassociate_ctty(0); | |
1571 | proc_clear_tty(tsk); | |
1572 | } | |
1573 | ||
af9b897e AC |
1574 | |
1575 | /** | |
1576 | * stop_tty - propogate flow control | |
1577 | * @tty: tty to stop | |
1578 | * | |
1579 | * Perform flow control to the driver. For PTY/TTY pairs we | |
1580 | * must also propogate the TIOCKPKT status. May be called | |
1581 | * on an already stopped device and will not re-call the driver | |
1582 | * method. | |
1583 | * | |
1584 | * This functionality is used by both the line disciplines for | |
1585 | * halting incoming flow and by the driver. It may therefore be | |
1586 | * called from any context, may be under the tty atomic_write_lock | |
1587 | * but not always. | |
1588 | * | |
1589 | * Locking: | |
1590 | * Broken. Relies on BKL which is unsafe here. | |
1591 | */ | |
1592 | ||
1da177e4 LT |
1593 | void stop_tty(struct tty_struct *tty) |
1594 | { | |
1595 | if (tty->stopped) | |
1596 | return; | |
1597 | tty->stopped = 1; | |
1598 | if (tty->link && tty->link->packet) { | |
1599 | tty->ctrl_status &= ~TIOCPKT_START; | |
1600 | tty->ctrl_status |= TIOCPKT_STOP; | |
1601 | wake_up_interruptible(&tty->link->read_wait); | |
1602 | } | |
1603 | if (tty->driver->stop) | |
1604 | (tty->driver->stop)(tty); | |
1605 | } | |
1606 | ||
1607 | EXPORT_SYMBOL(stop_tty); | |
1608 | ||
af9b897e AC |
1609 | /** |
1610 | * start_tty - propogate flow control | |
1611 | * @tty: tty to start | |
1612 | * | |
1613 | * Start a tty that has been stopped if at all possible. Perform | |
1614 | * any neccessary wakeups and propogate the TIOCPKT status. If this | |
1615 | * is the tty was previous stopped and is being started then the | |
1616 | * driver start method is invoked and the line discipline woken. | |
1617 | * | |
1618 | * Locking: | |
1619 | * Broken. Relies on BKL which is unsafe here. | |
1620 | */ | |
1621 | ||
1da177e4 LT |
1622 | void start_tty(struct tty_struct *tty) |
1623 | { | |
1624 | if (!tty->stopped || tty->flow_stopped) | |
1625 | return; | |
1626 | tty->stopped = 0; | |
1627 | if (tty->link && tty->link->packet) { | |
1628 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
1629 | tty->ctrl_status |= TIOCPKT_START; | |
1630 | wake_up_interruptible(&tty->link->read_wait); | |
1631 | } | |
1632 | if (tty->driver->start) | |
1633 | (tty->driver->start)(tty); | |
1634 | ||
1635 | /* If we have a running line discipline it may need kicking */ | |
1636 | tty_wakeup(tty); | |
1da177e4 LT |
1637 | } |
1638 | ||
1639 | EXPORT_SYMBOL(start_tty); | |
1640 | ||
af9b897e AC |
1641 | /** |
1642 | * tty_read - read method for tty device files | |
1643 | * @file: pointer to tty file | |
1644 | * @buf: user buffer | |
1645 | * @count: size of user buffer | |
1646 | * @ppos: unused | |
1647 | * | |
1648 | * Perform the read system call function on this terminal device. Checks | |
1649 | * for hung up devices before calling the line discipline method. | |
1650 | * | |
1651 | * Locking: | |
1652 | * Locks the line discipline internally while needed | |
1653 | * For historical reasons the line discipline read method is | |
1654 | * invoked under the BKL. This will go away in time so do not rely on it | |
1655 | * in new code. Multiple read calls may be outstanding in parallel. | |
1656 | */ | |
1657 | ||
1da177e4 LT |
1658 | static ssize_t tty_read(struct file * file, char __user * buf, size_t count, |
1659 | loff_t *ppos) | |
1660 | { | |
1661 | int i; | |
1662 | struct tty_struct * tty; | |
1663 | struct inode *inode; | |
1664 | struct tty_ldisc *ld; | |
1665 | ||
1666 | tty = (struct tty_struct *)file->private_data; | |
a7113a96 | 1667 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1668 | if (tty_paranoia_check(tty, inode, "tty_read")) |
1669 | return -EIO; | |
1670 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1671 | return -EIO; | |
1672 | ||
1673 | /* We want to wait for the line discipline to sort out in this | |
1674 | situation */ | |
1675 | ld = tty_ldisc_ref_wait(tty); | |
1676 | lock_kernel(); | |
1677 | if (ld->read) | |
1678 | i = (ld->read)(tty,file,buf,count); | |
1679 | else | |
1680 | i = -EIO; | |
1681 | tty_ldisc_deref(ld); | |
1682 | unlock_kernel(); | |
1683 | if (i > 0) | |
1684 | inode->i_atime = current_fs_time(inode->i_sb); | |
1685 | return i; | |
1686 | } | |
1687 | ||
1688 | /* | |
1689 | * Split writes up in sane blocksizes to avoid | |
1690 | * denial-of-service type attacks | |
1691 | */ | |
1692 | static inline ssize_t do_tty_write( | |
1693 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
1694 | struct tty_struct *tty, | |
1695 | struct file *file, | |
1696 | const char __user *buf, | |
1697 | size_t count) | |
1698 | { | |
1699 | ssize_t ret = 0, written = 0; | |
1700 | unsigned int chunk; | |
1701 | ||
af9b897e | 1702 | /* FIXME: O_NDELAY ... */ |
70522e12 | 1703 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) { |
1da177e4 LT |
1704 | return -ERESTARTSYS; |
1705 | } | |
1706 | ||
1707 | /* | |
1708 | * We chunk up writes into a temporary buffer. This | |
1709 | * simplifies low-level drivers immensely, since they | |
1710 | * don't have locking issues and user mode accesses. | |
1711 | * | |
1712 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
1713 | * big chunk-size.. | |
1714 | * | |
1715 | * The default chunk-size is 2kB, because the NTTY | |
1716 | * layer has problems with bigger chunks. It will | |
1717 | * claim to be able to handle more characters than | |
1718 | * it actually does. | |
af9b897e AC |
1719 | * |
1720 | * FIXME: This can probably go away now except that 64K chunks | |
1721 | * are too likely to fail unless switched to vmalloc... | |
1da177e4 LT |
1722 | */ |
1723 | chunk = 2048; | |
1724 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
1725 | chunk = 65536; | |
1726 | if (count < chunk) | |
1727 | chunk = count; | |
1728 | ||
70522e12 | 1729 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
1da177e4 LT |
1730 | if (tty->write_cnt < chunk) { |
1731 | unsigned char *buf; | |
1732 | ||
1733 | if (chunk < 1024) | |
1734 | chunk = 1024; | |
1735 | ||
1736 | buf = kmalloc(chunk, GFP_KERNEL); | |
1737 | if (!buf) { | |
70522e12 | 1738 | mutex_unlock(&tty->atomic_write_lock); |
1da177e4 LT |
1739 | return -ENOMEM; |
1740 | } | |
1741 | kfree(tty->write_buf); | |
1742 | tty->write_cnt = chunk; | |
1743 | tty->write_buf = buf; | |
1744 | } | |
1745 | ||
1746 | /* Do the write .. */ | |
1747 | for (;;) { | |
1748 | size_t size = count; | |
1749 | if (size > chunk) | |
1750 | size = chunk; | |
1751 | ret = -EFAULT; | |
1752 | if (copy_from_user(tty->write_buf, buf, size)) | |
1753 | break; | |
1754 | lock_kernel(); | |
1755 | ret = write(tty, file, tty->write_buf, size); | |
1756 | unlock_kernel(); | |
1757 | if (ret <= 0) | |
1758 | break; | |
1759 | written += ret; | |
1760 | buf += ret; | |
1761 | count -= ret; | |
1762 | if (!count) | |
1763 | break; | |
1764 | ret = -ERESTARTSYS; | |
1765 | if (signal_pending(current)) | |
1766 | break; | |
1767 | cond_resched(); | |
1768 | } | |
1769 | if (written) { | |
a7113a96 | 1770 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1771 | inode->i_mtime = current_fs_time(inode->i_sb); |
1772 | ret = written; | |
1773 | } | |
70522e12 | 1774 | mutex_unlock(&tty->atomic_write_lock); |
1da177e4 LT |
1775 | return ret; |
1776 | } | |
1777 | ||
1778 | ||
af9b897e AC |
1779 | /** |
1780 | * tty_write - write method for tty device file | |
1781 | * @file: tty file pointer | |
1782 | * @buf: user data to write | |
1783 | * @count: bytes to write | |
1784 | * @ppos: unused | |
1785 | * | |
1786 | * Write data to a tty device via the line discipline. | |
1787 | * | |
1788 | * Locking: | |
1789 | * Locks the line discipline as required | |
1790 | * Writes to the tty driver are serialized by the atomic_write_lock | |
1791 | * and are then processed in chunks to the device. The line discipline | |
1792 | * write method will not be involked in parallel for each device | |
1793 | * The line discipline write method is called under the big | |
1794 | * kernel lock for historical reasons. New code should not rely on this. | |
1795 | */ | |
1796 | ||
1da177e4 LT |
1797 | static ssize_t tty_write(struct file * file, const char __user * buf, size_t count, |
1798 | loff_t *ppos) | |
1799 | { | |
1800 | struct tty_struct * tty; | |
a7113a96 | 1801 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1802 | ssize_t ret; |
1803 | struct tty_ldisc *ld; | |
1804 | ||
1805 | tty = (struct tty_struct *)file->private_data; | |
1806 | if (tty_paranoia_check(tty, inode, "tty_write")) | |
1807 | return -EIO; | |
1808 | if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1809 | return -EIO; | |
1810 | ||
1811 | ld = tty_ldisc_ref_wait(tty); | |
1812 | if (!ld->write) | |
1813 | ret = -EIO; | |
1814 | else | |
1815 | ret = do_tty_write(ld->write, tty, file, buf, count); | |
1816 | tty_ldisc_deref(ld); | |
1817 | return ret; | |
1818 | } | |
1819 | ||
1820 | ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count, | |
1821 | loff_t *ppos) | |
1822 | { | |
1823 | struct file *p = NULL; | |
1824 | ||
1825 | spin_lock(&redirect_lock); | |
1826 | if (redirect) { | |
1827 | get_file(redirect); | |
1828 | p = redirect; | |
1829 | } | |
1830 | spin_unlock(&redirect_lock); | |
1831 | ||
1832 | if (p) { | |
1833 | ssize_t res; | |
1834 | res = vfs_write(p, buf, count, &p->f_pos); | |
1835 | fput(p); | |
1836 | return res; | |
1837 | } | |
1838 | ||
1839 | return tty_write(file, buf, count, ppos); | |
1840 | } | |
1841 | ||
1842 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
1843 | ||
af9b897e AC |
1844 | /** |
1845 | * pty_line_name - generate name for a pty | |
1846 | * @driver: the tty driver in use | |
1847 | * @index: the minor number | |
1848 | * @p: output buffer of at least 6 bytes | |
1849 | * | |
1850 | * Generate a name from a driver reference and write it to the output | |
1851 | * buffer. | |
1852 | * | |
1853 | * Locking: None | |
1854 | */ | |
1855 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1856 | { |
1857 | int i = index + driver->name_base; | |
1858 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
1859 | sprintf(p, "%s%c%x", | |
1860 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, | |
1861 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1862 | } | |
1863 | ||
af9b897e AC |
1864 | /** |
1865 | * pty_line_name - generate name for a tty | |
1866 | * @driver: the tty driver in use | |
1867 | * @index: the minor number | |
1868 | * @p: output buffer of at least 7 bytes | |
1869 | * | |
1870 | * Generate a name from a driver reference and write it to the output | |
1871 | * buffer. | |
1872 | * | |
1873 | * Locking: None | |
1874 | */ | |
1875 | static void tty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1876 | { |
1877 | sprintf(p, "%s%d", driver->name, index + driver->name_base); | |
1878 | } | |
1879 | ||
af9b897e AC |
1880 | /** |
1881 | * init_dev - initialise a tty device | |
1882 | * @driver: tty driver we are opening a device on | |
1883 | * @idx: device index | |
1884 | * @tty: returned tty structure | |
1885 | * | |
1886 | * Prepare a tty device. This may not be a "new" clean device but | |
1887 | * could also be an active device. The pty drivers require special | |
1888 | * handling because of this. | |
1889 | * | |
1890 | * Locking: | |
1891 | * The function is called under the tty_mutex, which | |
1892 | * protects us from the tty struct or driver itself going away. | |
1893 | * | |
1894 | * On exit the tty device has the line discipline attached and | |
1895 | * a reference count of 1. If a pair was created for pty/tty use | |
1896 | * and the other was a pty master then it too has a reference count of 1. | |
1897 | * | |
1da177e4 | 1898 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
70522e12 IM |
1899 | * failed open. The new code protects the open with a mutex, so it's |
1900 | * really quite straightforward. The mutex locking can probably be | |
1da177e4 LT |
1901 | * relaxed for the (most common) case of reopening a tty. |
1902 | */ | |
af9b897e | 1903 | |
1da177e4 LT |
1904 | static int init_dev(struct tty_driver *driver, int idx, |
1905 | struct tty_struct **ret_tty) | |
1906 | { | |
1907 | struct tty_struct *tty, *o_tty; | |
edc6afc5 AC |
1908 | struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; |
1909 | struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; | |
af9b897e | 1910 | int retval = 0; |
1da177e4 LT |
1911 | |
1912 | /* check whether we're reopening an existing tty */ | |
1913 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
1914 | tty = devpts_get_tty(idx); | |
5a39e8c6 ASRF |
1915 | /* |
1916 | * If we don't have a tty here on a slave open, it's because | |
1917 | * the master already started the close process and there's | |
1918 | * no relation between devpts file and tty anymore. | |
1919 | */ | |
1920 | if (!tty && driver->subtype == PTY_TYPE_SLAVE) { | |
1921 | retval = -EIO; | |
1922 | goto end_init; | |
1923 | } | |
1924 | /* | |
1925 | * It's safe from now on because init_dev() is called with | |
1926 | * tty_mutex held and release_dev() won't change tty->count | |
1927 | * or tty->flags without having to grab tty_mutex | |
1928 | */ | |
1da177e4 LT |
1929 | if (tty && driver->subtype == PTY_TYPE_MASTER) |
1930 | tty = tty->link; | |
1931 | } else { | |
1932 | tty = driver->ttys[idx]; | |
1933 | } | |
1934 | if (tty) goto fast_track; | |
1935 | ||
1936 | /* | |
1937 | * First time open is complex, especially for PTY devices. | |
1938 | * This code guarantees that either everything succeeds and the | |
1939 | * TTY is ready for operation, or else the table slots are vacated | |
1940 | * and the allocated memory released. (Except that the termios | |
1941 | * and locked termios may be retained.) | |
1942 | */ | |
1943 | ||
1944 | if (!try_module_get(driver->owner)) { | |
1945 | retval = -ENODEV; | |
1946 | goto end_init; | |
1947 | } | |
1948 | ||
1949 | o_tty = NULL; | |
1950 | tp = o_tp = NULL; | |
1951 | ltp = o_ltp = NULL; | |
1952 | ||
1953 | tty = alloc_tty_struct(); | |
1954 | if(!tty) | |
1955 | goto fail_no_mem; | |
1956 | initialize_tty_struct(tty); | |
1957 | tty->driver = driver; | |
1958 | tty->index = idx; | |
1959 | tty_line_name(driver, idx, tty->name); | |
1960 | ||
1961 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
1962 | tp_loc = &tty->termios; | |
1963 | ltp_loc = &tty->termios_locked; | |
1964 | } else { | |
1965 | tp_loc = &driver->termios[idx]; | |
1966 | ltp_loc = &driver->termios_locked[idx]; | |
1967 | } | |
1968 | ||
1969 | if (!*tp_loc) { | |
edc6afc5 | 1970 | tp = (struct ktermios *) kmalloc(sizeof(struct ktermios), |
1da177e4 LT |
1971 | GFP_KERNEL); |
1972 | if (!tp) | |
1973 | goto free_mem_out; | |
1974 | *tp = driver->init_termios; | |
1975 | } | |
1976 | ||
1977 | if (!*ltp_loc) { | |
edc6afc5 | 1978 | ltp = (struct ktermios *) kmalloc(sizeof(struct ktermios), |
1da177e4 LT |
1979 | GFP_KERNEL); |
1980 | if (!ltp) | |
1981 | goto free_mem_out; | |
edc6afc5 | 1982 | memset(ltp, 0, sizeof(struct ktermios)); |
1da177e4 LT |
1983 | } |
1984 | ||
1985 | if (driver->type == TTY_DRIVER_TYPE_PTY) { | |
1986 | o_tty = alloc_tty_struct(); | |
1987 | if (!o_tty) | |
1988 | goto free_mem_out; | |
1989 | initialize_tty_struct(o_tty); | |
1990 | o_tty->driver = driver->other; | |
1991 | o_tty->index = idx; | |
1992 | tty_line_name(driver->other, idx, o_tty->name); | |
1993 | ||
1994 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
1995 | o_tp_loc = &o_tty->termios; | |
1996 | o_ltp_loc = &o_tty->termios_locked; | |
1997 | } else { | |
1998 | o_tp_loc = &driver->other->termios[idx]; | |
1999 | o_ltp_loc = &driver->other->termios_locked[idx]; | |
2000 | } | |
2001 | ||
2002 | if (!*o_tp_loc) { | |
edc6afc5 AC |
2003 | o_tp = (struct ktermios *) |
2004 | kmalloc(sizeof(struct ktermios), GFP_KERNEL); | |
1da177e4 LT |
2005 | if (!o_tp) |
2006 | goto free_mem_out; | |
2007 | *o_tp = driver->other->init_termios; | |
2008 | } | |
2009 | ||
2010 | if (!*o_ltp_loc) { | |
edc6afc5 AC |
2011 | o_ltp = (struct ktermios *) |
2012 | kmalloc(sizeof(struct ktermios), GFP_KERNEL); | |
1da177e4 LT |
2013 | if (!o_ltp) |
2014 | goto free_mem_out; | |
edc6afc5 | 2015 | memset(o_ltp, 0, sizeof(struct ktermios)); |
1da177e4 LT |
2016 | } |
2017 | ||
2018 | /* | |
2019 | * Everything allocated ... set up the o_tty structure. | |
2020 | */ | |
2021 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2022 | driver->other->ttys[idx] = o_tty; | |
2023 | } | |
2024 | if (!*o_tp_loc) | |
2025 | *o_tp_loc = o_tp; | |
2026 | if (!*o_ltp_loc) | |
2027 | *o_ltp_loc = o_ltp; | |
2028 | o_tty->termios = *o_tp_loc; | |
2029 | o_tty->termios_locked = *o_ltp_loc; | |
2030 | driver->other->refcount++; | |
2031 | if (driver->subtype == PTY_TYPE_MASTER) | |
2032 | o_tty->count++; | |
2033 | ||
2034 | /* Establish the links in both directions */ | |
2035 | tty->link = o_tty; | |
2036 | o_tty->link = tty; | |
2037 | } | |
2038 | ||
2039 | /* | |
2040 | * All structures have been allocated, so now we install them. | |
d5698c28 | 2041 | * Failures after this point use release_tty to clean up, so |
1da177e4 LT |
2042 | * there's no need to null out the local pointers. |
2043 | */ | |
2044 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2045 | driver->ttys[idx] = tty; | |
2046 | } | |
2047 | ||
2048 | if (!*tp_loc) | |
2049 | *tp_loc = tp; | |
2050 | if (!*ltp_loc) | |
2051 | *ltp_loc = ltp; | |
2052 | tty->termios = *tp_loc; | |
2053 | tty->termios_locked = *ltp_loc; | |
edc6afc5 AC |
2054 | /* Compatibility until drivers always set this */ |
2055 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
2056 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1da177e4 LT |
2057 | driver->refcount++; |
2058 | tty->count++; | |
2059 | ||
2060 | /* | |
2061 | * Structures all installed ... call the ldisc open routines. | |
d5698c28 CH |
2062 | * If we fail here just call release_tty to clean up. No need |
2063 | * to decrement the use counts, as release_tty doesn't care. | |
1da177e4 LT |
2064 | */ |
2065 | ||
2066 | if (tty->ldisc.open) { | |
2067 | retval = (tty->ldisc.open)(tty); | |
2068 | if (retval) | |
2069 | goto release_mem_out; | |
2070 | } | |
2071 | if (o_tty && o_tty->ldisc.open) { | |
2072 | retval = (o_tty->ldisc.open)(o_tty); | |
2073 | if (retval) { | |
2074 | if (tty->ldisc.close) | |
2075 | (tty->ldisc.close)(tty); | |
2076 | goto release_mem_out; | |
2077 | } | |
2078 | tty_ldisc_enable(o_tty); | |
2079 | } | |
2080 | tty_ldisc_enable(tty); | |
2081 | goto success; | |
2082 | ||
2083 | /* | |
2084 | * This fast open can be used if the tty is already open. | |
2085 | * No memory is allocated, and the only failures are from | |
2086 | * attempting to open a closing tty or attempting multiple | |
2087 | * opens on a pty master. | |
2088 | */ | |
2089 | fast_track: | |
2090 | if (test_bit(TTY_CLOSING, &tty->flags)) { | |
2091 | retval = -EIO; | |
2092 | goto end_init; | |
2093 | } | |
2094 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
2095 | driver->subtype == PTY_TYPE_MASTER) { | |
2096 | /* | |
2097 | * special case for PTY masters: only one open permitted, | |
2098 | * and the slave side open count is incremented as well. | |
2099 | */ | |
2100 | if (tty->count) { | |
2101 | retval = -EIO; | |
2102 | goto end_init; | |
2103 | } | |
2104 | tty->link->count++; | |
2105 | } | |
2106 | tty->count++; | |
2107 | tty->driver = driver; /* N.B. why do this every time?? */ | |
2108 | ||
2109 | /* FIXME */ | |
2110 | if(!test_bit(TTY_LDISC, &tty->flags)) | |
2111 | printk(KERN_ERR "init_dev but no ldisc\n"); | |
2112 | success: | |
2113 | *ret_tty = tty; | |
2114 | ||
70522e12 | 2115 | /* All paths come through here to release the mutex */ |
1da177e4 LT |
2116 | end_init: |
2117 | return retval; | |
2118 | ||
2119 | /* Release locally allocated memory ... nothing placed in slots */ | |
2120 | free_mem_out: | |
735d5661 | 2121 | kfree(o_tp); |
1da177e4 LT |
2122 | if (o_tty) |
2123 | free_tty_struct(o_tty); | |
735d5661 JJ |
2124 | kfree(ltp); |
2125 | kfree(tp); | |
1da177e4 LT |
2126 | free_tty_struct(tty); |
2127 | ||
2128 | fail_no_mem: | |
2129 | module_put(driver->owner); | |
2130 | retval = -ENOMEM; | |
2131 | goto end_init; | |
2132 | ||
d5698c28 | 2133 | /* call the tty release_tty routine to clean out this slot */ |
1da177e4 | 2134 | release_mem_out: |
4050914f AM |
2135 | if (printk_ratelimit()) |
2136 | printk(KERN_INFO "init_dev: ldisc open failed, " | |
2137 | "clearing slot %d\n", idx); | |
d5698c28 | 2138 | release_tty(tty, idx); |
1da177e4 LT |
2139 | goto end_init; |
2140 | } | |
2141 | ||
af9b897e | 2142 | /** |
d5698c28 | 2143 | * release_one_tty - release tty structure memory |
af9b897e AC |
2144 | * |
2145 | * Releases memory associated with a tty structure, and clears out the | |
2146 | * driver table slots. This function is called when a device is no longer | |
2147 | * in use. It also gets called when setup of a device fails. | |
2148 | * | |
2149 | * Locking: | |
2150 | * tty_mutex - sometimes only | |
2151 | * takes the file list lock internally when working on the list | |
2152 | * of ttys that the driver keeps. | |
2153 | * FIXME: should we require tty_mutex is held here ?? | |
1da177e4 | 2154 | */ |
d5698c28 | 2155 | static void release_one_tty(struct tty_struct *tty, int idx) |
1da177e4 | 2156 | { |
1da177e4 | 2157 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
d5698c28 | 2158 | struct ktermios *tp; |
1da177e4 LT |
2159 | |
2160 | if (!devpts) | |
2161 | tty->driver->ttys[idx] = NULL; | |
d5698c28 | 2162 | |
1da177e4 LT |
2163 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
2164 | tp = tty->termios; | |
2165 | if (!devpts) | |
2166 | tty->driver->termios[idx] = NULL; | |
2167 | kfree(tp); | |
2168 | ||
2169 | tp = tty->termios_locked; | |
2170 | if (!devpts) | |
2171 | tty->driver->termios_locked[idx] = NULL; | |
2172 | kfree(tp); | |
2173 | } | |
2174 | ||
d5698c28 | 2175 | |
1da177e4 LT |
2176 | tty->magic = 0; |
2177 | tty->driver->refcount--; | |
d5698c28 | 2178 | |
1da177e4 LT |
2179 | file_list_lock(); |
2180 | list_del_init(&tty->tty_files); | |
2181 | file_list_unlock(); | |
d5698c28 | 2182 | |
1da177e4 LT |
2183 | free_tty_struct(tty); |
2184 | } | |
2185 | ||
d5698c28 CH |
2186 | /** |
2187 | * release_tty - release tty structure memory | |
2188 | * | |
2189 | * Release both @tty and a possible linked partner (think pty pair), | |
2190 | * and decrement the refcount of the backing module. | |
2191 | * | |
2192 | * Locking: | |
2193 | * tty_mutex - sometimes only | |
2194 | * takes the file list lock internally when working on the list | |
2195 | * of ttys that the driver keeps. | |
2196 | * FIXME: should we require tty_mutex is held here ?? | |
2197 | */ | |
2198 | static void release_tty(struct tty_struct *tty, int idx) | |
2199 | { | |
2200 | struct tty_driver *driver = tty->driver; | |
2201 | ||
2202 | if (tty->link) | |
2203 | release_one_tty(tty->link, idx); | |
2204 | release_one_tty(tty, idx); | |
2205 | module_put(driver->owner); | |
2206 | } | |
2207 | ||
1da177e4 LT |
2208 | /* |
2209 | * Even releasing the tty structures is a tricky business.. We have | |
2210 | * to be very careful that the structures are all released at the | |
2211 | * same time, as interrupts might otherwise get the wrong pointers. | |
2212 | * | |
2213 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
2214 | * lead to double frees or releasing memory still in use. | |
2215 | */ | |
2216 | static void release_dev(struct file * filp) | |
2217 | { | |
2218 | struct tty_struct *tty, *o_tty; | |
2219 | int pty_master, tty_closing, o_tty_closing, do_sleep; | |
14a6283e | 2220 | int devpts; |
1da177e4 LT |
2221 | int idx; |
2222 | char buf[64]; | |
2223 | unsigned long flags; | |
2224 | ||
2225 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2226 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "release_dev")) |
1da177e4 LT |
2227 | return; |
2228 | ||
2229 | check_tty_count(tty, "release_dev"); | |
2230 | ||
2231 | tty_fasync(-1, filp, 0); | |
2232 | ||
2233 | idx = tty->index; | |
2234 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2235 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2236 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; | |
1da177e4 LT |
2237 | o_tty = tty->link; |
2238 | ||
2239 | #ifdef TTY_PARANOIA_CHECK | |
2240 | if (idx < 0 || idx >= tty->driver->num) { | |
2241 | printk(KERN_DEBUG "release_dev: bad idx when trying to " | |
2242 | "free (%s)\n", tty->name); | |
2243 | return; | |
2244 | } | |
2245 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2246 | if (tty != tty->driver->ttys[idx]) { | |
2247 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " | |
2248 | "for (%s)\n", idx, tty->name); | |
2249 | return; | |
2250 | } | |
2251 | if (tty->termios != tty->driver->termios[idx]) { | |
2252 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " | |
2253 | "for (%s)\n", | |
2254 | idx, tty->name); | |
2255 | return; | |
2256 | } | |
2257 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { | |
2258 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " | |
2259 | "termios_locked for (%s)\n", | |
2260 | idx, tty->name); | |
2261 | return; | |
2262 | } | |
2263 | } | |
2264 | #endif | |
2265 | ||
2266 | #ifdef TTY_DEBUG_HANGUP | |
2267 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", | |
2268 | tty_name(tty, buf), tty->count); | |
2269 | #endif | |
2270 | ||
2271 | #ifdef TTY_PARANOIA_CHECK | |
2272 | if (tty->driver->other && | |
2273 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2274 | if (o_tty != tty->driver->other->ttys[idx]) { | |
2275 | printk(KERN_DEBUG "release_dev: other->table[%d] " | |
2276 | "not o_tty for (%s)\n", | |
2277 | idx, tty->name); | |
2278 | return; | |
2279 | } | |
2280 | if (o_tty->termios != tty->driver->other->termios[idx]) { | |
2281 | printk(KERN_DEBUG "release_dev: other->termios[%d] " | |
2282 | "not o_termios for (%s)\n", | |
2283 | idx, tty->name); | |
2284 | return; | |
2285 | } | |
2286 | if (o_tty->termios_locked != | |
2287 | tty->driver->other->termios_locked[idx]) { | |
2288 | printk(KERN_DEBUG "release_dev: other->termios_locked[" | |
2289 | "%d] not o_termios_locked for (%s)\n", | |
2290 | idx, tty->name); | |
2291 | return; | |
2292 | } | |
2293 | if (o_tty->link != tty) { | |
2294 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); | |
2295 | return; | |
2296 | } | |
2297 | } | |
2298 | #endif | |
2299 | if (tty->driver->close) | |
2300 | tty->driver->close(tty, filp); | |
2301 | ||
2302 | /* | |
2303 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
2304 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
2305 | * wait queues and kick everyone out _before_ actually starting to | |
2306 | * close. This ensures that we won't block while releasing the tty | |
2307 | * structure. | |
2308 | * | |
2309 | * The test for the o_tty closing is necessary, since the master and | |
2310 | * slave sides may close in any order. If the slave side closes out | |
2311 | * first, its count will be one, since the master side holds an open. | |
2312 | * Thus this test wouldn't be triggered at the time the slave closes, | |
2313 | * so we do it now. | |
2314 | * | |
2315 | * Note that it's possible for the tty to be opened again while we're | |
2316 | * flushing out waiters. By recalculating the closing flags before | |
2317 | * each iteration we avoid any problems. | |
2318 | */ | |
2319 | while (1) { | |
2320 | /* Guard against races with tty->count changes elsewhere and | |
2321 | opens on /dev/tty */ | |
2322 | ||
70522e12 | 2323 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2324 | tty_closing = tty->count <= 1; |
2325 | o_tty_closing = o_tty && | |
2326 | (o_tty->count <= (pty_master ? 1 : 0)); | |
1da177e4 LT |
2327 | do_sleep = 0; |
2328 | ||
2329 | if (tty_closing) { | |
2330 | if (waitqueue_active(&tty->read_wait)) { | |
2331 | wake_up(&tty->read_wait); | |
2332 | do_sleep++; | |
2333 | } | |
2334 | if (waitqueue_active(&tty->write_wait)) { | |
2335 | wake_up(&tty->write_wait); | |
2336 | do_sleep++; | |
2337 | } | |
2338 | } | |
2339 | if (o_tty_closing) { | |
2340 | if (waitqueue_active(&o_tty->read_wait)) { | |
2341 | wake_up(&o_tty->read_wait); | |
2342 | do_sleep++; | |
2343 | } | |
2344 | if (waitqueue_active(&o_tty->write_wait)) { | |
2345 | wake_up(&o_tty->write_wait); | |
2346 | do_sleep++; | |
2347 | } | |
2348 | } | |
2349 | if (!do_sleep) | |
2350 | break; | |
2351 | ||
2352 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " | |
2353 | "active!\n", tty_name(tty, buf)); | |
70522e12 | 2354 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2355 | schedule(); |
2356 | } | |
2357 | ||
2358 | /* | |
2359 | * The closing flags are now consistent with the open counts on | |
2360 | * both sides, and we've completed the last operation that could | |
2361 | * block, so it's safe to proceed with closing. | |
2362 | */ | |
1da177e4 LT |
2363 | if (pty_master) { |
2364 | if (--o_tty->count < 0) { | |
2365 | printk(KERN_WARNING "release_dev: bad pty slave count " | |
2366 | "(%d) for %s\n", | |
2367 | o_tty->count, tty_name(o_tty, buf)); | |
2368 | o_tty->count = 0; | |
2369 | } | |
2370 | } | |
2371 | if (--tty->count < 0) { | |
2372 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", | |
2373 | tty->count, tty_name(tty, buf)); | |
2374 | tty->count = 0; | |
2375 | } | |
1da177e4 LT |
2376 | |
2377 | /* | |
2378 | * We've decremented tty->count, so we need to remove this file | |
2379 | * descriptor off the tty->tty_files list; this serves two | |
2380 | * purposes: | |
2381 | * - check_tty_count sees the correct number of file descriptors | |
2382 | * associated with this tty. | |
2383 | * - do_tty_hangup no longer sees this file descriptor as | |
2384 | * something that needs to be handled for hangups. | |
2385 | */ | |
2386 | file_kill(filp); | |
2387 | filp->private_data = NULL; | |
2388 | ||
2389 | /* | |
2390 | * Perform some housekeeping before deciding whether to return. | |
2391 | * | |
2392 | * Set the TTY_CLOSING flag if this was the last open. In the | |
2393 | * case of a pty we may have to wait around for the other side | |
2394 | * to close, and TTY_CLOSING makes sure we can't be reopened. | |
2395 | */ | |
2396 | if(tty_closing) | |
2397 | set_bit(TTY_CLOSING, &tty->flags); | |
2398 | if(o_tty_closing) | |
2399 | set_bit(TTY_CLOSING, &o_tty->flags); | |
2400 | ||
2401 | /* | |
2402 | * If _either_ side is closing, make sure there aren't any | |
2403 | * processes that still think tty or o_tty is their controlling | |
2404 | * tty. | |
2405 | */ | |
2406 | if (tty_closing || o_tty_closing) { | |
1da177e4 | 2407 | read_lock(&tasklist_lock); |
24ec839c | 2408 | session_clear_tty(tty->session); |
1da177e4 | 2409 | if (o_tty) |
24ec839c | 2410 | session_clear_tty(o_tty->session); |
1da177e4 LT |
2411 | read_unlock(&tasklist_lock); |
2412 | } | |
2413 | ||
70522e12 | 2414 | mutex_unlock(&tty_mutex); |
da965822 | 2415 | |
1da177e4 LT |
2416 | /* check whether both sides are closing ... */ |
2417 | if (!tty_closing || (o_tty && !o_tty_closing)) | |
2418 | return; | |
2419 | ||
2420 | #ifdef TTY_DEBUG_HANGUP | |
2421 | printk(KERN_DEBUG "freeing tty structure..."); | |
2422 | #endif | |
2423 | /* | |
2424 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then | |
2425 | * kill any delayed work. As this is the final close it does not | |
2426 | * race with the set_ldisc code path. | |
2427 | */ | |
2428 | clear_bit(TTY_LDISC, &tty->flags); | |
33f0f88f | 2429 | cancel_delayed_work(&tty->buf.work); |
1da177e4 LT |
2430 | |
2431 | /* | |
33f0f88f | 2432 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 LT |
2433 | */ |
2434 | ||
2435 | flush_scheduled_work(); | |
2436 | ||
2437 | /* | |
2438 | * Wait for any short term users (we know they are just driver | |
2439 | * side waiters as the file is closing so user count on the file | |
2440 | * side is zero. | |
2441 | */ | |
2442 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2443 | while(tty->ldisc.refcount) | |
2444 | { | |
2445 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2446 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); | |
2447 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2448 | } | |
2449 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2450 | /* | |
2451 | * Shutdown the current line discipline, and reset it to N_TTY. | |
2452 | * N.B. why reset ldisc when we're releasing the memory?? | |
2453 | * | |
2454 | * FIXME: this MUST get fixed for the new reflocking | |
2455 | */ | |
2456 | if (tty->ldisc.close) | |
2457 | (tty->ldisc.close)(tty); | |
2458 | tty_ldisc_put(tty->ldisc.num); | |
2459 | ||
2460 | /* | |
2461 | * Switch the line discipline back | |
2462 | */ | |
2463 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
2464 | tty_set_termios_ldisc(tty,N_TTY); | |
2465 | if (o_tty) { | |
2466 | /* FIXME: could o_tty be in setldisc here ? */ | |
2467 | clear_bit(TTY_LDISC, &o_tty->flags); | |
2468 | if (o_tty->ldisc.close) | |
2469 | (o_tty->ldisc.close)(o_tty); | |
2470 | tty_ldisc_put(o_tty->ldisc.num); | |
2471 | tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); | |
2472 | tty_set_termios_ldisc(o_tty,N_TTY); | |
2473 | } | |
2474 | /* | |
d5698c28 | 2475 | * The release_tty function takes care of the details of clearing |
1da177e4 LT |
2476 | * the slots and preserving the termios structure. |
2477 | */ | |
d5698c28 | 2478 | release_tty(tty, idx); |
1da177e4 LT |
2479 | |
2480 | #ifdef CONFIG_UNIX98_PTYS | |
2481 | /* Make this pty number available for reallocation */ | |
2482 | if (devpts) { | |
2483 | down(&allocated_ptys_lock); | |
2484 | idr_remove(&allocated_ptys, idx); | |
2485 | up(&allocated_ptys_lock); | |
2486 | } | |
2487 | #endif | |
2488 | ||
2489 | } | |
2490 | ||
af9b897e AC |
2491 | /** |
2492 | * tty_open - open a tty device | |
2493 | * @inode: inode of device file | |
2494 | * @filp: file pointer to tty | |
1da177e4 | 2495 | * |
af9b897e AC |
2496 | * tty_open and tty_release keep up the tty count that contains the |
2497 | * number of opens done on a tty. We cannot use the inode-count, as | |
2498 | * different inodes might point to the same tty. | |
1da177e4 | 2499 | * |
af9b897e AC |
2500 | * Open-counting is needed for pty masters, as well as for keeping |
2501 | * track of serial lines: DTR is dropped when the last close happens. | |
2502 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
2503 | * | |
2504 | * The termios state of a pty is reset on first open so that | |
2505 | * settings don't persist across reuse. | |
2506 | * | |
24ec839c PZ |
2507 | * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. |
2508 | * tty->count should protect the rest. | |
2509 | * ->siglock protects ->signal/->sighand | |
1da177e4 | 2510 | */ |
af9b897e | 2511 | |
1da177e4 LT |
2512 | static int tty_open(struct inode * inode, struct file * filp) |
2513 | { | |
2514 | struct tty_struct *tty; | |
2515 | int noctty, retval; | |
2516 | struct tty_driver *driver; | |
2517 | int index; | |
2518 | dev_t device = inode->i_rdev; | |
2519 | unsigned short saved_flags = filp->f_flags; | |
2520 | ||
2521 | nonseekable_open(inode, filp); | |
2522 | ||
2523 | retry_open: | |
2524 | noctty = filp->f_flags & O_NOCTTY; | |
2525 | index = -1; | |
2526 | retval = 0; | |
2527 | ||
70522e12 | 2528 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2529 | |
2530 | if (device == MKDEV(TTYAUX_MAJOR,0)) { | |
24ec839c PZ |
2531 | tty = get_current_tty(); |
2532 | if (!tty) { | |
70522e12 | 2533 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2534 | return -ENXIO; |
2535 | } | |
24ec839c PZ |
2536 | driver = tty->driver; |
2537 | index = tty->index; | |
1da177e4 LT |
2538 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
2539 | /* noctty = 1; */ | |
2540 | goto got_driver; | |
2541 | } | |
2542 | #ifdef CONFIG_VT | |
2543 | if (device == MKDEV(TTY_MAJOR,0)) { | |
2544 | extern struct tty_driver *console_driver; | |
2545 | driver = console_driver; | |
2546 | index = fg_console; | |
2547 | noctty = 1; | |
2548 | goto got_driver; | |
2549 | } | |
2550 | #endif | |
2551 | if (device == MKDEV(TTYAUX_MAJOR,1)) { | |
2552 | driver = console_device(&index); | |
2553 | if (driver) { | |
2554 | /* Don't let /dev/console block */ | |
2555 | filp->f_flags |= O_NONBLOCK; | |
2556 | noctty = 1; | |
2557 | goto got_driver; | |
2558 | } | |
70522e12 | 2559 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2560 | return -ENODEV; |
2561 | } | |
2562 | ||
2563 | driver = get_tty_driver(device, &index); | |
2564 | if (!driver) { | |
70522e12 | 2565 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2566 | return -ENODEV; |
2567 | } | |
2568 | got_driver: | |
2569 | retval = init_dev(driver, index, &tty); | |
70522e12 | 2570 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2571 | if (retval) |
2572 | return retval; | |
2573 | ||
2574 | filp->private_data = tty; | |
2575 | file_move(filp, &tty->tty_files); | |
2576 | check_tty_count(tty, "tty_open"); | |
2577 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2578 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2579 | noctty = 1; | |
2580 | #ifdef TTY_DEBUG_HANGUP | |
2581 | printk(KERN_DEBUG "opening %s...", tty->name); | |
2582 | #endif | |
2583 | if (!retval) { | |
2584 | if (tty->driver->open) | |
2585 | retval = tty->driver->open(tty, filp); | |
2586 | else | |
2587 | retval = -ENODEV; | |
2588 | } | |
2589 | filp->f_flags = saved_flags; | |
2590 | ||
2591 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) | |
2592 | retval = -EBUSY; | |
2593 | ||
2594 | if (retval) { | |
2595 | #ifdef TTY_DEBUG_HANGUP | |
2596 | printk(KERN_DEBUG "error %d in opening %s...", retval, | |
2597 | tty->name); | |
2598 | #endif | |
2599 | release_dev(filp); | |
2600 | if (retval != -ERESTARTSYS) | |
2601 | return retval; | |
2602 | if (signal_pending(current)) | |
2603 | return retval; | |
2604 | schedule(); | |
2605 | /* | |
2606 | * Need to reset f_op in case a hangup happened. | |
2607 | */ | |
2608 | if (filp->f_op == &hung_up_tty_fops) | |
2609 | filp->f_op = &tty_fops; | |
2610 | goto retry_open; | |
2611 | } | |
24ec839c PZ |
2612 | |
2613 | mutex_lock(&tty_mutex); | |
2614 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2615 | if (!noctty && |
2616 | current->signal->leader && | |
2617 | !current->signal->tty && | |
ab521dc0 | 2618 | tty->session == NULL) |
2a65f1d9 | 2619 | __proc_set_tty(current, tty); |
24ec839c PZ |
2620 | spin_unlock_irq(¤t->sighand->siglock); |
2621 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
2622 | return 0; |
2623 | } | |
2624 | ||
2625 | #ifdef CONFIG_UNIX98_PTYS | |
af9b897e AC |
2626 | /** |
2627 | * ptmx_open - open a unix 98 pty master | |
2628 | * @inode: inode of device file | |
2629 | * @filp: file pointer to tty | |
2630 | * | |
2631 | * Allocate a unix98 pty master device from the ptmx driver. | |
2632 | * | |
2633 | * Locking: tty_mutex protects theinit_dev work. tty->count should | |
2634 | protect the rest. | |
2635 | * allocated_ptys_lock handles the list of free pty numbers | |
2636 | */ | |
2637 | ||
1da177e4 LT |
2638 | static int ptmx_open(struct inode * inode, struct file * filp) |
2639 | { | |
2640 | struct tty_struct *tty; | |
2641 | int retval; | |
2642 | int index; | |
2643 | int idr_ret; | |
2644 | ||
2645 | nonseekable_open(inode, filp); | |
2646 | ||
2647 | /* find a device that is not in use. */ | |
2648 | down(&allocated_ptys_lock); | |
2649 | if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { | |
2650 | up(&allocated_ptys_lock); | |
2651 | return -ENOMEM; | |
2652 | } | |
2653 | idr_ret = idr_get_new(&allocated_ptys, NULL, &index); | |
2654 | if (idr_ret < 0) { | |
2655 | up(&allocated_ptys_lock); | |
2656 | if (idr_ret == -EAGAIN) | |
2657 | return -ENOMEM; | |
2658 | return -EIO; | |
2659 | } | |
2660 | if (index >= pty_limit) { | |
2661 | idr_remove(&allocated_ptys, index); | |
2662 | up(&allocated_ptys_lock); | |
2663 | return -EIO; | |
2664 | } | |
2665 | up(&allocated_ptys_lock); | |
2666 | ||
70522e12 | 2667 | mutex_lock(&tty_mutex); |
1da177e4 | 2668 | retval = init_dev(ptm_driver, index, &tty); |
70522e12 | 2669 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2670 | |
2671 | if (retval) | |
2672 | goto out; | |
2673 | ||
2674 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
2675 | filp->private_data = tty; | |
2676 | file_move(filp, &tty->tty_files); | |
2677 | ||
2678 | retval = -ENOMEM; | |
2679 | if (devpts_pty_new(tty->link)) | |
2680 | goto out1; | |
2681 | ||
2682 | check_tty_count(tty, "tty_open"); | |
2683 | retval = ptm_driver->open(tty, filp); | |
2684 | if (!retval) | |
2685 | return 0; | |
2686 | out1: | |
2687 | release_dev(filp); | |
9453a5ad | 2688 | return retval; |
1da177e4 LT |
2689 | out: |
2690 | down(&allocated_ptys_lock); | |
2691 | idr_remove(&allocated_ptys, index); | |
2692 | up(&allocated_ptys_lock); | |
2693 | return retval; | |
2694 | } | |
2695 | #endif | |
2696 | ||
af9b897e AC |
2697 | /** |
2698 | * tty_release - vfs callback for close | |
2699 | * @inode: inode of tty | |
2700 | * @filp: file pointer for handle to tty | |
2701 | * | |
2702 | * Called the last time each file handle is closed that references | |
2703 | * this tty. There may however be several such references. | |
2704 | * | |
2705 | * Locking: | |
2706 | * Takes bkl. See release_dev | |
2707 | */ | |
2708 | ||
1da177e4 LT |
2709 | static int tty_release(struct inode * inode, struct file * filp) |
2710 | { | |
2711 | lock_kernel(); | |
2712 | release_dev(filp); | |
2713 | unlock_kernel(); | |
2714 | return 0; | |
2715 | } | |
2716 | ||
af9b897e AC |
2717 | /** |
2718 | * tty_poll - check tty status | |
2719 | * @filp: file being polled | |
2720 | * @wait: poll wait structures to update | |
2721 | * | |
2722 | * Call the line discipline polling method to obtain the poll | |
2723 | * status of the device. | |
2724 | * | |
2725 | * Locking: locks called line discipline but ldisc poll method | |
2726 | * may be re-entered freely by other callers. | |
2727 | */ | |
2728 | ||
1da177e4 LT |
2729 | static unsigned int tty_poll(struct file * filp, poll_table * wait) |
2730 | { | |
2731 | struct tty_struct * tty; | |
2732 | struct tty_ldisc *ld; | |
2733 | int ret = 0; | |
2734 | ||
2735 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2736 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) |
1da177e4 LT |
2737 | return 0; |
2738 | ||
2739 | ld = tty_ldisc_ref_wait(tty); | |
2740 | if (ld->poll) | |
2741 | ret = (ld->poll)(tty, filp, wait); | |
2742 | tty_ldisc_deref(ld); | |
2743 | return ret; | |
2744 | } | |
2745 | ||
2746 | static int tty_fasync(int fd, struct file * filp, int on) | |
2747 | { | |
2748 | struct tty_struct * tty; | |
2749 | int retval; | |
2750 | ||
2751 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2752 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) |
1da177e4 LT |
2753 | return 0; |
2754 | ||
2755 | retval = fasync_helper(fd, filp, on, &tty->fasync); | |
2756 | if (retval <= 0) | |
2757 | return retval; | |
2758 | ||
2759 | if (on) { | |
ab521dc0 EB |
2760 | enum pid_type type; |
2761 | struct pid *pid; | |
1da177e4 LT |
2762 | if (!waitqueue_active(&tty->read_wait)) |
2763 | tty->minimum_to_wake = 1; | |
ab521dc0 EB |
2764 | if (tty->pgrp) { |
2765 | pid = tty->pgrp; | |
2766 | type = PIDTYPE_PGID; | |
2767 | } else { | |
2768 | pid = task_pid(current); | |
2769 | type = PIDTYPE_PID; | |
2770 | } | |
2771 | retval = __f_setown(filp, pid, type, 0); | |
1da177e4 LT |
2772 | if (retval) |
2773 | return retval; | |
2774 | } else { | |
2775 | if (!tty->fasync && !waitqueue_active(&tty->read_wait)) | |
2776 | tty->minimum_to_wake = N_TTY_BUF_SIZE; | |
2777 | } | |
2778 | return 0; | |
2779 | } | |
2780 | ||
af9b897e AC |
2781 | /** |
2782 | * tiocsti - fake input character | |
2783 | * @tty: tty to fake input into | |
2784 | * @p: pointer to character | |
2785 | * | |
2786 | * Fake input to a tty device. Does the neccessary locking and | |
2787 | * input management. | |
2788 | * | |
2789 | * FIXME: does not honour flow control ?? | |
2790 | * | |
2791 | * Locking: | |
2792 | * Called functions take tty_ldisc_lock | |
2793 | * current->signal->tty check is safe without locks | |
28298232 AC |
2794 | * |
2795 | * FIXME: may race normal receive processing | |
af9b897e AC |
2796 | */ |
2797 | ||
1da177e4 LT |
2798 | static int tiocsti(struct tty_struct *tty, char __user *p) |
2799 | { | |
2800 | char ch, mbz = 0; | |
2801 | struct tty_ldisc *ld; | |
2802 | ||
2803 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) | |
2804 | return -EPERM; | |
2805 | if (get_user(ch, p)) | |
2806 | return -EFAULT; | |
2807 | ld = tty_ldisc_ref_wait(tty); | |
2808 | ld->receive_buf(tty, &ch, &mbz, 1); | |
2809 | tty_ldisc_deref(ld); | |
2810 | return 0; | |
2811 | } | |
2812 | ||
af9b897e AC |
2813 | /** |
2814 | * tiocgwinsz - implement window query ioctl | |
2815 | * @tty; tty | |
2816 | * @arg: user buffer for result | |
2817 | * | |
808a0d38 | 2818 | * Copies the kernel idea of the window size into the user buffer. |
af9b897e | 2819 | * |
24ec839c | 2820 | * Locking: tty->termios_mutex is taken to ensure the winsize data |
808a0d38 | 2821 | * is consistent. |
af9b897e AC |
2822 | */ |
2823 | ||
1da177e4 LT |
2824 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) |
2825 | { | |
808a0d38 AC |
2826 | int err; |
2827 | ||
5785c95b | 2828 | mutex_lock(&tty->termios_mutex); |
808a0d38 | 2829 | err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); |
5785c95b | 2830 | mutex_unlock(&tty->termios_mutex); |
808a0d38 AC |
2831 | |
2832 | return err ? -EFAULT: 0; | |
1da177e4 LT |
2833 | } |
2834 | ||
af9b897e AC |
2835 | /** |
2836 | * tiocswinsz - implement window size set ioctl | |
2837 | * @tty; tty | |
2838 | * @arg: user buffer for result | |
2839 | * | |
2840 | * Copies the user idea of the window size to the kernel. Traditionally | |
2841 | * this is just advisory information but for the Linux console it | |
2842 | * actually has driver level meaning and triggers a VC resize. | |
2843 | * | |
2844 | * Locking: | |
ca9bda00 AC |
2845 | * Called function use the console_sem is used to ensure we do |
2846 | * not try and resize the console twice at once. | |
24ec839c PZ |
2847 | * The tty->termios_mutex is used to ensure we don't double |
2848 | * resize and get confused. Lock order - tty->termios_mutex before | |
ca9bda00 | 2849 | * console sem |
af9b897e AC |
2850 | */ |
2851 | ||
1da177e4 LT |
2852 | static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, |
2853 | struct winsize __user * arg) | |
2854 | { | |
2855 | struct winsize tmp_ws; | |
2856 | ||
2857 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
2858 | return -EFAULT; | |
ca9bda00 | 2859 | |
5785c95b | 2860 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 2861 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
ca9bda00 AC |
2862 | goto done; |
2863 | ||
1da177e4 LT |
2864 | #ifdef CONFIG_VT |
2865 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { | |
5785c95b AV |
2866 | if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, |
2867 | tmp_ws.ws_row)) { | |
2868 | mutex_unlock(&tty->termios_mutex); | |
ca9bda00 AC |
2869 | return -ENXIO; |
2870 | } | |
1da177e4 LT |
2871 | } |
2872 | #endif | |
ab521dc0 EB |
2873 | if (tty->pgrp) |
2874 | kill_pgrp(tty->pgrp, SIGWINCH, 1); | |
2875 | if ((real_tty->pgrp != tty->pgrp) && real_tty->pgrp) | |
2876 | kill_pgrp(real_tty->pgrp, SIGWINCH, 1); | |
1da177e4 LT |
2877 | tty->winsize = tmp_ws; |
2878 | real_tty->winsize = tmp_ws; | |
ca9bda00 | 2879 | done: |
5785c95b | 2880 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
2881 | return 0; |
2882 | } | |
2883 | ||
af9b897e AC |
2884 | /** |
2885 | * tioccons - allow admin to move logical console | |
2886 | * @file: the file to become console | |
2887 | * | |
2888 | * Allow the adminstrator to move the redirected console device | |
2889 | * | |
2890 | * Locking: uses redirect_lock to guard the redirect information | |
2891 | */ | |
2892 | ||
1da177e4 LT |
2893 | static int tioccons(struct file *file) |
2894 | { | |
2895 | if (!capable(CAP_SYS_ADMIN)) | |
2896 | return -EPERM; | |
2897 | if (file->f_op->write == redirected_tty_write) { | |
2898 | struct file *f; | |
2899 | spin_lock(&redirect_lock); | |
2900 | f = redirect; | |
2901 | redirect = NULL; | |
2902 | spin_unlock(&redirect_lock); | |
2903 | if (f) | |
2904 | fput(f); | |
2905 | return 0; | |
2906 | } | |
2907 | spin_lock(&redirect_lock); | |
2908 | if (redirect) { | |
2909 | spin_unlock(&redirect_lock); | |
2910 | return -EBUSY; | |
2911 | } | |
2912 | get_file(file); | |
2913 | redirect = file; | |
2914 | spin_unlock(&redirect_lock); | |
2915 | return 0; | |
2916 | } | |
2917 | ||
af9b897e AC |
2918 | /** |
2919 | * fionbio - non blocking ioctl | |
2920 | * @file: file to set blocking value | |
2921 | * @p: user parameter | |
2922 | * | |
2923 | * Historical tty interfaces had a blocking control ioctl before | |
2924 | * the generic functionality existed. This piece of history is preserved | |
2925 | * in the expected tty API of posix OS's. | |
2926 | * | |
2927 | * Locking: none, the open fle handle ensures it won't go away. | |
2928 | */ | |
1da177e4 LT |
2929 | |
2930 | static int fionbio(struct file *file, int __user *p) | |
2931 | { | |
2932 | int nonblock; | |
2933 | ||
2934 | if (get_user(nonblock, p)) | |
2935 | return -EFAULT; | |
2936 | ||
2937 | if (nonblock) | |
2938 | file->f_flags |= O_NONBLOCK; | |
2939 | else | |
2940 | file->f_flags &= ~O_NONBLOCK; | |
2941 | return 0; | |
2942 | } | |
2943 | ||
af9b897e AC |
2944 | /** |
2945 | * tiocsctty - set controlling tty | |
2946 | * @tty: tty structure | |
2947 | * @arg: user argument | |
2948 | * | |
2949 | * This ioctl is used to manage job control. It permits a session | |
2950 | * leader to set this tty as the controlling tty for the session. | |
2951 | * | |
2952 | * Locking: | |
28298232 | 2953 | * Takes tty_mutex() to protect tty instance |
24ec839c PZ |
2954 | * Takes tasklist_lock internally to walk sessions |
2955 | * Takes ->siglock() when updating signal->tty | |
af9b897e AC |
2956 | */ |
2957 | ||
1da177e4 LT |
2958 | static int tiocsctty(struct tty_struct *tty, int arg) |
2959 | { | |
24ec839c | 2960 | int ret = 0; |
ab521dc0 | 2961 | if (current->signal->leader && (task_session(current) == tty->session)) |
24ec839c PZ |
2962 | return ret; |
2963 | ||
2964 | mutex_lock(&tty_mutex); | |
1da177e4 LT |
2965 | /* |
2966 | * The process must be a session leader and | |
2967 | * not have a controlling tty already. | |
2968 | */ | |
24ec839c PZ |
2969 | if (!current->signal->leader || current->signal->tty) { |
2970 | ret = -EPERM; | |
2971 | goto unlock; | |
2972 | } | |
2973 | ||
ab521dc0 | 2974 | if (tty->session) { |
1da177e4 LT |
2975 | /* |
2976 | * This tty is already the controlling | |
2977 | * tty for another session group! | |
2978 | */ | |
2979 | if ((arg == 1) && capable(CAP_SYS_ADMIN)) { | |
2980 | /* | |
2981 | * Steal it away | |
2982 | */ | |
1da177e4 | 2983 | read_lock(&tasklist_lock); |
24ec839c | 2984 | session_clear_tty(tty->session); |
1da177e4 | 2985 | read_unlock(&tasklist_lock); |
24ec839c PZ |
2986 | } else { |
2987 | ret = -EPERM; | |
2988 | goto unlock; | |
2989 | } | |
1da177e4 | 2990 | } |
24ec839c PZ |
2991 | proc_set_tty(current, tty); |
2992 | unlock: | |
28298232 | 2993 | mutex_unlock(&tty_mutex); |
24ec839c | 2994 | return ret; |
1da177e4 LT |
2995 | } |
2996 | ||
af9b897e AC |
2997 | /** |
2998 | * tiocgpgrp - get process group | |
2999 | * @tty: tty passed by user | |
3000 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3001 | * @p: returned pid | |
3002 | * | |
3003 | * Obtain the process group of the tty. If there is no process group | |
3004 | * return an error. | |
3005 | * | |
24ec839c | 3006 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3007 | */ |
3008 | ||
1da177e4 LT |
3009 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3010 | { | |
3011 | /* | |
3012 | * (tty == real_tty) is a cheap way of | |
3013 | * testing if the tty is NOT a master pty. | |
3014 | */ | |
3015 | if (tty == real_tty && current->signal->tty != real_tty) | |
3016 | return -ENOTTY; | |
ab521dc0 | 3017 | return put_user(pid_nr(real_tty->pgrp), p); |
1da177e4 LT |
3018 | } |
3019 | ||
af9b897e AC |
3020 | /** |
3021 | * tiocspgrp - attempt to set process group | |
3022 | * @tty: tty passed by user | |
3023 | * @real_tty: tty side device matching tty passed by user | |
3024 | * @p: pid pointer | |
3025 | * | |
3026 | * Set the process group of the tty to the session passed. Only | |
3027 | * permitted where the tty session is our session. | |
3028 | * | |
3029 | * Locking: None | |
af9b897e AC |
3030 | */ |
3031 | ||
1da177e4 LT |
3032 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3033 | { | |
04a2e6a5 EB |
3034 | struct pid *pgrp; |
3035 | pid_t pgrp_nr; | |
1da177e4 LT |
3036 | int retval = tty_check_change(real_tty); |
3037 | ||
3038 | if (retval == -EIO) | |
3039 | return -ENOTTY; | |
3040 | if (retval) | |
3041 | return retval; | |
3042 | if (!current->signal->tty || | |
3043 | (current->signal->tty != real_tty) || | |
ab521dc0 | 3044 | (real_tty->session != task_session(current))) |
1da177e4 | 3045 | return -ENOTTY; |
04a2e6a5 | 3046 | if (get_user(pgrp_nr, p)) |
1da177e4 | 3047 | return -EFAULT; |
04a2e6a5 | 3048 | if (pgrp_nr < 0) |
1da177e4 | 3049 | return -EINVAL; |
04a2e6a5 EB |
3050 | rcu_read_lock(); |
3051 | pgrp = find_pid(pgrp_nr); | |
3052 | retval = -ESRCH; | |
3053 | if (!pgrp) | |
3054 | goto out_unlock; | |
3055 | retval = -EPERM; | |
3056 | if (session_of_pgrp(pgrp) != task_session(current)) | |
3057 | goto out_unlock; | |
3058 | retval = 0; | |
ab521dc0 EB |
3059 | put_pid(real_tty->pgrp); |
3060 | real_tty->pgrp = get_pid(pgrp); | |
04a2e6a5 EB |
3061 | out_unlock: |
3062 | rcu_read_unlock(); | |
3063 | return retval; | |
1da177e4 LT |
3064 | } |
3065 | ||
af9b897e AC |
3066 | /** |
3067 | * tiocgsid - get session id | |
3068 | * @tty: tty passed by user | |
3069 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3070 | * @p: pointer to returned session id | |
3071 | * | |
3072 | * Obtain the session id of the tty. If there is no session | |
3073 | * return an error. | |
3074 | * | |
24ec839c | 3075 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3076 | */ |
3077 | ||
1da177e4 LT |
3078 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3079 | { | |
3080 | /* | |
3081 | * (tty == real_tty) is a cheap way of | |
3082 | * testing if the tty is NOT a master pty. | |
3083 | */ | |
3084 | if (tty == real_tty && current->signal->tty != real_tty) | |
3085 | return -ENOTTY; | |
ab521dc0 | 3086 | if (!real_tty->session) |
1da177e4 | 3087 | return -ENOTTY; |
ab521dc0 | 3088 | return put_user(pid_nr(real_tty->session), p); |
1da177e4 LT |
3089 | } |
3090 | ||
af9b897e AC |
3091 | /** |
3092 | * tiocsetd - set line discipline | |
3093 | * @tty: tty device | |
3094 | * @p: pointer to user data | |
3095 | * | |
3096 | * Set the line discipline according to user request. | |
3097 | * | |
3098 | * Locking: see tty_set_ldisc, this function is just a helper | |
3099 | */ | |
3100 | ||
1da177e4 LT |
3101 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
3102 | { | |
3103 | int ldisc; | |
3104 | ||
3105 | if (get_user(ldisc, p)) | |
3106 | return -EFAULT; | |
3107 | return tty_set_ldisc(tty, ldisc); | |
3108 | } | |
3109 | ||
af9b897e AC |
3110 | /** |
3111 | * send_break - performed time break | |
3112 | * @tty: device to break on | |
3113 | * @duration: timeout in mS | |
3114 | * | |
3115 | * Perform a timed break on hardware that lacks its own driver level | |
3116 | * timed break functionality. | |
3117 | * | |
3118 | * Locking: | |
28298232 | 3119 | * atomic_write_lock serializes |
af9b897e | 3120 | * |
af9b897e AC |
3121 | */ |
3122 | ||
b20f3ae5 | 3123 | static int send_break(struct tty_struct *tty, unsigned int duration) |
1da177e4 | 3124 | { |
28298232 AC |
3125 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) |
3126 | return -EINTR; | |
1da177e4 LT |
3127 | tty->driver->break_ctl(tty, -1); |
3128 | if (!signal_pending(current)) { | |
b20f3ae5 | 3129 | msleep_interruptible(duration); |
1da177e4 LT |
3130 | } |
3131 | tty->driver->break_ctl(tty, 0); | |
28298232 | 3132 | mutex_unlock(&tty->atomic_write_lock); |
1da177e4 LT |
3133 | if (signal_pending(current)) |
3134 | return -EINTR; | |
3135 | return 0; | |
3136 | } | |
3137 | ||
af9b897e AC |
3138 | /** |
3139 | * tiocmget - get modem status | |
3140 | * @tty: tty device | |
3141 | * @file: user file pointer | |
3142 | * @p: pointer to result | |
3143 | * | |
3144 | * Obtain the modem status bits from the tty driver if the feature | |
3145 | * is supported. Return -EINVAL if it is not available. | |
3146 | * | |
3147 | * Locking: none (up to the driver) | |
3148 | */ | |
3149 | ||
3150 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) | |
1da177e4 LT |
3151 | { |
3152 | int retval = -EINVAL; | |
3153 | ||
3154 | if (tty->driver->tiocmget) { | |
3155 | retval = tty->driver->tiocmget(tty, file); | |
3156 | ||
3157 | if (retval >= 0) | |
3158 | retval = put_user(retval, p); | |
3159 | } | |
3160 | return retval; | |
3161 | } | |
3162 | ||
af9b897e AC |
3163 | /** |
3164 | * tiocmset - set modem status | |
3165 | * @tty: tty device | |
3166 | * @file: user file pointer | |
3167 | * @cmd: command - clear bits, set bits or set all | |
3168 | * @p: pointer to desired bits | |
3169 | * | |
3170 | * Set the modem status bits from the tty driver if the feature | |
3171 | * is supported. Return -EINVAL if it is not available. | |
3172 | * | |
3173 | * Locking: none (up to the driver) | |
3174 | */ | |
3175 | ||
3176 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, | |
1da177e4 LT |
3177 | unsigned __user *p) |
3178 | { | |
3179 | int retval = -EINVAL; | |
3180 | ||
3181 | if (tty->driver->tiocmset) { | |
3182 | unsigned int set, clear, val; | |
3183 | ||
3184 | retval = get_user(val, p); | |
3185 | if (retval) | |
3186 | return retval; | |
3187 | ||
3188 | set = clear = 0; | |
3189 | switch (cmd) { | |
3190 | case TIOCMBIS: | |
3191 | set = val; | |
3192 | break; | |
3193 | case TIOCMBIC: | |
3194 | clear = val; | |
3195 | break; | |
3196 | case TIOCMSET: | |
3197 | set = val; | |
3198 | clear = ~val; | |
3199 | break; | |
3200 | } | |
3201 | ||
3202 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3203 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3204 | ||
3205 | retval = tty->driver->tiocmset(tty, file, set, clear); | |
3206 | } | |
3207 | return retval; | |
3208 | } | |
3209 | ||
3210 | /* | |
3211 | * Split this up, as gcc can choke on it otherwise.. | |
3212 | */ | |
3213 | int tty_ioctl(struct inode * inode, struct file * file, | |
3214 | unsigned int cmd, unsigned long arg) | |
3215 | { | |
3216 | struct tty_struct *tty, *real_tty; | |
3217 | void __user *p = (void __user *)arg; | |
3218 | int retval; | |
3219 | struct tty_ldisc *ld; | |
3220 | ||
3221 | tty = (struct tty_struct *)file->private_data; | |
3222 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3223 | return -EINVAL; | |
3224 | ||
28298232 AC |
3225 | /* CHECKME: is this safe as one end closes ? */ |
3226 | ||
1da177e4 LT |
3227 | real_tty = tty; |
3228 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
3229 | tty->driver->subtype == PTY_TYPE_MASTER) | |
3230 | real_tty = tty->link; | |
3231 | ||
3232 | /* | |
3233 | * Break handling by driver | |
3234 | */ | |
3235 | if (!tty->driver->break_ctl) { | |
3236 | switch(cmd) { | |
3237 | case TIOCSBRK: | |
3238 | case TIOCCBRK: | |
3239 | if (tty->driver->ioctl) | |
3240 | return tty->driver->ioctl(tty, file, cmd, arg); | |
3241 | return -EINVAL; | |
3242 | ||
3243 | /* These two ioctl's always return success; even if */ | |
3244 | /* the driver doesn't support them. */ | |
3245 | case TCSBRK: | |
3246 | case TCSBRKP: | |
3247 | if (!tty->driver->ioctl) | |
3248 | return 0; | |
3249 | retval = tty->driver->ioctl(tty, file, cmd, arg); | |
3250 | if (retval == -ENOIOCTLCMD) | |
3251 | retval = 0; | |
3252 | return retval; | |
3253 | } | |
3254 | } | |
3255 | ||
3256 | /* | |
3257 | * Factor out some common prep work | |
3258 | */ | |
3259 | switch (cmd) { | |
3260 | case TIOCSETD: | |
3261 | case TIOCSBRK: | |
3262 | case TIOCCBRK: | |
3263 | case TCSBRK: | |
3264 | case TCSBRKP: | |
3265 | retval = tty_check_change(tty); | |
3266 | if (retval) | |
3267 | return retval; | |
3268 | if (cmd != TIOCCBRK) { | |
3269 | tty_wait_until_sent(tty, 0); | |
3270 | if (signal_pending(current)) | |
3271 | return -EINTR; | |
3272 | } | |
3273 | break; | |
3274 | } | |
3275 | ||
3276 | switch (cmd) { | |
3277 | case TIOCSTI: | |
3278 | return tiocsti(tty, p); | |
3279 | case TIOCGWINSZ: | |
3280 | return tiocgwinsz(tty, p); | |
3281 | case TIOCSWINSZ: | |
3282 | return tiocswinsz(tty, real_tty, p); | |
3283 | case TIOCCONS: | |
3284 | return real_tty!=tty ? -EINVAL : tioccons(file); | |
3285 | case FIONBIO: | |
3286 | return fionbio(file, p); | |
3287 | case TIOCEXCL: | |
3288 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
3289 | return 0; | |
3290 | case TIOCNXCL: | |
3291 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
3292 | return 0; | |
3293 | case TIOCNOTTY: | |
3294 | if (current->signal->tty != tty) | |
3295 | return -ENOTTY; | |
98a27ba4 | 3296 | no_tty(); |
1da177e4 LT |
3297 | return 0; |
3298 | case TIOCSCTTY: | |
3299 | return tiocsctty(tty, arg); | |
3300 | case TIOCGPGRP: | |
3301 | return tiocgpgrp(tty, real_tty, p); | |
3302 | case TIOCSPGRP: | |
3303 | return tiocspgrp(tty, real_tty, p); | |
3304 | case TIOCGSID: | |
3305 | return tiocgsid(tty, real_tty, p); | |
3306 | case TIOCGETD: | |
3307 | /* FIXME: check this is ok */ | |
3308 | return put_user(tty->ldisc.num, (int __user *)p); | |
3309 | case TIOCSETD: | |
3310 | return tiocsetd(tty, p); | |
3311 | #ifdef CONFIG_VT | |
3312 | case TIOCLINUX: | |
3313 | return tioclinux(tty, arg); | |
3314 | #endif | |
3315 | /* | |
3316 | * Break handling | |
3317 | */ | |
3318 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
3319 | tty->driver->break_ctl(tty, -1); | |
3320 | return 0; | |
3321 | ||
3322 | case TIOCCBRK: /* Turn break off, unconditionally */ | |
3323 | tty->driver->break_ctl(tty, 0); | |
3324 | return 0; | |
3325 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
283fef59 PF |
3326 | /* non-zero arg means wait for all output data |
3327 | * to be sent (performed above) but don't send break. | |
3328 | * This is used by the tcdrain() termios function. | |
1da177e4 LT |
3329 | */ |
3330 | if (!arg) | |
b20f3ae5 | 3331 | return send_break(tty, 250); |
1da177e4 LT |
3332 | return 0; |
3333 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
b20f3ae5 | 3334 | return send_break(tty, arg ? arg*100 : 250); |
1da177e4 LT |
3335 | |
3336 | case TIOCMGET: | |
3337 | return tty_tiocmget(tty, file, p); | |
3338 | ||
3339 | case TIOCMSET: | |
3340 | case TIOCMBIC: | |
3341 | case TIOCMBIS: | |
3342 | return tty_tiocmset(tty, file, cmd, p); | |
3343 | } | |
3344 | if (tty->driver->ioctl) { | |
3345 | retval = (tty->driver->ioctl)(tty, file, cmd, arg); | |
3346 | if (retval != -ENOIOCTLCMD) | |
3347 | return retval; | |
3348 | } | |
3349 | ld = tty_ldisc_ref_wait(tty); | |
3350 | retval = -EINVAL; | |
3351 | if (ld->ioctl) { | |
3352 | retval = ld->ioctl(tty, file, cmd, arg); | |
3353 | if (retval == -ENOIOCTLCMD) | |
3354 | retval = -EINVAL; | |
3355 | } | |
3356 | tty_ldisc_deref(ld); | |
3357 | return retval; | |
3358 | } | |
3359 | ||
3360 | ||
3361 | /* | |
3362 | * This implements the "Secure Attention Key" --- the idea is to | |
3363 | * prevent trojan horses by killing all processes associated with this | |
3364 | * tty when the user hits the "Secure Attention Key". Required for | |
3365 | * super-paranoid applications --- see the Orange Book for more details. | |
3366 | * | |
3367 | * This code could be nicer; ideally it should send a HUP, wait a few | |
3368 | * seconds, then send a INT, and then a KILL signal. But you then | |
3369 | * have to coordinate with the init process, since all processes associated | |
3370 | * with the current tty must be dead before the new getty is allowed | |
3371 | * to spawn. | |
3372 | * | |
3373 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
3374 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
3375 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
3376 | * | |
3377 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
3378 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
3379 | */ | |
8b6312f4 | 3380 | void __do_SAK(struct tty_struct *tty) |
1da177e4 LT |
3381 | { |
3382 | #ifdef TTY_SOFT_SAK | |
3383 | tty_hangup(tty); | |
3384 | #else | |
652486fb | 3385 | struct task_struct *g, *p; |
ab521dc0 | 3386 | struct pid *session; |
1da177e4 LT |
3387 | int i; |
3388 | struct file *filp; | |
badf1662 | 3389 | struct fdtable *fdt; |
1da177e4 LT |
3390 | |
3391 | if (!tty) | |
3392 | return; | |
24ec839c | 3393 | session = tty->session; |
1da177e4 | 3394 | |
b3f13deb | 3395 | tty_ldisc_flush(tty); |
1da177e4 LT |
3396 | |
3397 | if (tty->driver->flush_buffer) | |
3398 | tty->driver->flush_buffer(tty); | |
3399 | ||
3400 | read_lock(&tasklist_lock); | |
652486fb | 3401 | /* Kill the entire session */ |
ab521dc0 | 3402 | do_each_pid_task(session, PIDTYPE_SID, p) { |
652486fb | 3403 | printk(KERN_NOTICE "SAK: killed process %d" |
937949d9 | 3404 | " (%s): process_session(p)==tty->session\n", |
652486fb EB |
3405 | p->pid, p->comm); |
3406 | send_sig(SIGKILL, p, 1); | |
ab521dc0 | 3407 | } while_each_pid_task(session, PIDTYPE_SID, p); |
652486fb EB |
3408 | /* Now kill any processes that happen to have the |
3409 | * tty open. | |
3410 | */ | |
3411 | do_each_thread(g, p) { | |
3412 | if (p->signal->tty == tty) { | |
1da177e4 | 3413 | printk(KERN_NOTICE "SAK: killed process %d" |
937949d9 | 3414 | " (%s): process_session(p)==tty->session\n", |
1da177e4 LT |
3415 | p->pid, p->comm); |
3416 | send_sig(SIGKILL, p, 1); | |
3417 | continue; | |
3418 | } | |
3419 | task_lock(p); | |
3420 | if (p->files) { | |
ca99c1da DS |
3421 | /* |
3422 | * We don't take a ref to the file, so we must | |
3423 | * hold ->file_lock instead. | |
3424 | */ | |
3425 | spin_lock(&p->files->file_lock); | |
badf1662 DS |
3426 | fdt = files_fdtable(p->files); |
3427 | for (i=0; i < fdt->max_fds; i++) { | |
1da177e4 LT |
3428 | filp = fcheck_files(p->files, i); |
3429 | if (!filp) | |
3430 | continue; | |
3431 | if (filp->f_op->read == tty_read && | |
3432 | filp->private_data == tty) { | |
3433 | printk(KERN_NOTICE "SAK: killed process %d" | |
3434 | " (%s): fd#%d opened to the tty\n", | |
3435 | p->pid, p->comm, i); | |
20ac9437 | 3436 | force_sig(SIGKILL, p); |
1da177e4 LT |
3437 | break; |
3438 | } | |
3439 | } | |
ca99c1da | 3440 | spin_unlock(&p->files->file_lock); |
1da177e4 LT |
3441 | } |
3442 | task_unlock(p); | |
652486fb | 3443 | } while_each_thread(g, p); |
1da177e4 LT |
3444 | read_unlock(&tasklist_lock); |
3445 | #endif | |
3446 | } | |
3447 | ||
8b6312f4 EB |
3448 | static void do_SAK_work(struct work_struct *work) |
3449 | { | |
3450 | struct tty_struct *tty = | |
3451 | container_of(work, struct tty_struct, SAK_work); | |
3452 | __do_SAK(tty); | |
3453 | } | |
3454 | ||
1da177e4 LT |
3455 | /* |
3456 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
3457 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
3458 | * the values which we write to it will be identical to the values which it | |
3459 | * already has. --akpm | |
3460 | */ | |
3461 | void do_SAK(struct tty_struct *tty) | |
3462 | { | |
3463 | if (!tty) | |
3464 | return; | |
1da177e4 LT |
3465 | schedule_work(&tty->SAK_work); |
3466 | } | |
3467 | ||
3468 | EXPORT_SYMBOL(do_SAK); | |
3469 | ||
af9b897e AC |
3470 | /** |
3471 | * flush_to_ldisc | |
65f27f38 | 3472 | * @work: tty structure passed from work queue. |
af9b897e AC |
3473 | * |
3474 | * This routine is called out of the software interrupt to flush data | |
3475 | * from the buffer chain to the line discipline. | |
3476 | * | |
3477 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
3478 | * while invoking the line discipline receive_buf method. The | |
3479 | * receive_buf method is single threaded for each tty instance. | |
1da177e4 LT |
3480 | */ |
3481 | ||
65f27f38 | 3482 | static void flush_to_ldisc(struct work_struct *work) |
1da177e4 | 3483 | { |
65f27f38 DH |
3484 | struct tty_struct *tty = |
3485 | container_of(work, struct tty_struct, buf.work.work); | |
1da177e4 LT |
3486 | unsigned long flags; |
3487 | struct tty_ldisc *disc; | |
2c3bb20f | 3488 | struct tty_buffer *tbuf, *head; |
8977d929 PF |
3489 | char *char_buf; |
3490 | unsigned char *flag_buf; | |
1da177e4 LT |
3491 | |
3492 | disc = tty_ldisc_ref(tty); | |
3493 | if (disc == NULL) /* !TTY_LDISC */ | |
3494 | return; | |
3495 | ||
808249ce | 3496 | spin_lock_irqsave(&tty->buf.lock, flags); |
2c3bb20f PF |
3497 | head = tty->buf.head; |
3498 | if (head != NULL) { | |
3499 | tty->buf.head = NULL; | |
3500 | for (;;) { | |
3501 | int count = head->commit - head->read; | |
3502 | if (!count) { | |
3503 | if (head->next == NULL) | |
3504 | break; | |
3505 | tbuf = head; | |
3506 | head = head->next; | |
3507 | tty_buffer_free(tty, tbuf); | |
3508 | continue; | |
3509 | } | |
3510 | if (!tty->receive_room) { | |
3511 | schedule_delayed_work(&tty->buf.work, 1); | |
3512 | break; | |
3513 | } | |
3514 | if (count > tty->receive_room) | |
3515 | count = tty->receive_room; | |
3516 | char_buf = head->char_buf_ptr + head->read; | |
3517 | flag_buf = head->flag_buf_ptr + head->read; | |
3518 | head->read += count; | |
8977d929 PF |
3519 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3520 | disc->receive_buf(tty, char_buf, flag_buf, count); | |
3521 | spin_lock_irqsave(&tty->buf.lock, flags); | |
3522 | } | |
2c3bb20f | 3523 | tty->buf.head = head; |
33f0f88f | 3524 | } |
808249ce | 3525 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
817d6d3b | 3526 | |
1da177e4 LT |
3527 | tty_ldisc_deref(disc); |
3528 | } | |
3529 | ||
1da177e4 LT |
3530 | /** |
3531 | * tty_flip_buffer_push - terminal | |
3532 | * @tty: tty to push | |
3533 | * | |
3534 | * Queue a push of the terminal flip buffers to the line discipline. This | |
3535 | * function must not be called from IRQ context if tty->low_latency is set. | |
3536 | * | |
3537 | * In the event of the queue being busy for flipping the work will be | |
3538 | * held off and retried later. | |
af9b897e AC |
3539 | * |
3540 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
1da177e4 LT |
3541 | */ |
3542 | ||
3543 | void tty_flip_buffer_push(struct tty_struct *tty) | |
3544 | { | |
808249ce PF |
3545 | unsigned long flags; |
3546 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 3547 | if (tty->buf.tail != NULL) |
8977d929 | 3548 | tty->buf.tail->commit = tty->buf.tail->used; |
808249ce PF |
3549 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3550 | ||
1da177e4 | 3551 | if (tty->low_latency) |
65f27f38 | 3552 | flush_to_ldisc(&tty->buf.work.work); |
1da177e4 | 3553 | else |
33f0f88f | 3554 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
3555 | } |
3556 | ||
3557 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
3558 | ||
33f0f88f | 3559 | |
af9b897e AC |
3560 | /** |
3561 | * initialize_tty_struct | |
3562 | * @tty: tty to initialize | |
3563 | * | |
3564 | * This subroutine initializes a tty structure that has been newly | |
3565 | * allocated. | |
3566 | * | |
3567 | * Locking: none - tty in question must not be exposed at this point | |
1da177e4 | 3568 | */ |
af9b897e | 3569 | |
1da177e4 LT |
3570 | static void initialize_tty_struct(struct tty_struct *tty) |
3571 | { | |
3572 | memset(tty, 0, sizeof(struct tty_struct)); | |
3573 | tty->magic = TTY_MAGIC; | |
3574 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
ab521dc0 EB |
3575 | tty->session = NULL; |
3576 | tty->pgrp = NULL; | |
1da177e4 | 3577 | tty->overrun_time = jiffies; |
33f0f88f AC |
3578 | tty->buf.head = tty->buf.tail = NULL; |
3579 | tty_buffer_init(tty); | |
65f27f38 | 3580 | INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); |
33f0f88f | 3581 | init_MUTEX(&tty->buf.pty_sem); |
5785c95b | 3582 | mutex_init(&tty->termios_mutex); |
1da177e4 LT |
3583 | init_waitqueue_head(&tty->write_wait); |
3584 | init_waitqueue_head(&tty->read_wait); | |
65f27f38 | 3585 | INIT_WORK(&tty->hangup_work, do_tty_hangup); |
70522e12 IM |
3586 | mutex_init(&tty->atomic_read_lock); |
3587 | mutex_init(&tty->atomic_write_lock); | |
1da177e4 LT |
3588 | spin_lock_init(&tty->read_lock); |
3589 | INIT_LIST_HEAD(&tty->tty_files); | |
7f1f86a0 | 3590 | INIT_WORK(&tty->SAK_work, do_SAK_work); |
1da177e4 LT |
3591 | } |
3592 | ||
3593 | /* | |
3594 | * The default put_char routine if the driver did not define one. | |
3595 | */ | |
af9b897e | 3596 | |
1da177e4 LT |
3597 | static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) |
3598 | { | |
3599 | tty->driver->write(tty, &ch, 1); | |
3600 | } | |
3601 | ||
7fe845d1 | 3602 | static struct class *tty_class; |
1da177e4 LT |
3603 | |
3604 | /** | |
af9b897e AC |
3605 | * tty_register_device - register a tty device |
3606 | * @driver: the tty driver that describes the tty device | |
3607 | * @index: the index in the tty driver for this tty device | |
3608 | * @device: a struct device that is associated with this tty device. | |
3609 | * This field is optional, if there is no known struct device | |
3610 | * for this tty device it can be set to NULL safely. | |
1da177e4 | 3611 | * |
01107d34 GKH |
3612 | * Returns a pointer to the struct device for this tty device |
3613 | * (or ERR_PTR(-EFOO) on error). | |
1cdcb6b4 | 3614 | * |
af9b897e AC |
3615 | * This call is required to be made to register an individual tty device |
3616 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
3617 | * that bit is not set, this function should not be called by a tty | |
3618 | * driver. | |
3619 | * | |
3620 | * Locking: ?? | |
1da177e4 | 3621 | */ |
af9b897e | 3622 | |
01107d34 GKH |
3623 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
3624 | struct device *device) | |
1da177e4 LT |
3625 | { |
3626 | char name[64]; | |
3627 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; | |
3628 | ||
3629 | if (index >= driver->num) { | |
3630 | printk(KERN_ERR "Attempt to register invalid tty line number " | |
3631 | " (%d).\n", index); | |
1cdcb6b4 | 3632 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
3633 | } |
3634 | ||
1da177e4 LT |
3635 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
3636 | pty_line_name(driver, index, name); | |
3637 | else | |
3638 | tty_line_name(driver, index, name); | |
1cdcb6b4 | 3639 | |
01107d34 | 3640 | return device_create(tty_class, device, dev, name); |
1da177e4 LT |
3641 | } |
3642 | ||
3643 | /** | |
af9b897e AC |
3644 | * tty_unregister_device - unregister a tty device |
3645 | * @driver: the tty driver that describes the tty device | |
3646 | * @index: the index in the tty driver for this tty device | |
1da177e4 | 3647 | * |
af9b897e AC |
3648 | * If a tty device is registered with a call to tty_register_device() then |
3649 | * this function must be called when the tty device is gone. | |
3650 | * | |
3651 | * Locking: ?? | |
1da177e4 | 3652 | */ |
af9b897e | 3653 | |
1da177e4 LT |
3654 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
3655 | { | |
01107d34 | 3656 | device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); |
1da177e4 LT |
3657 | } |
3658 | ||
3659 | EXPORT_SYMBOL(tty_register_device); | |
3660 | EXPORT_SYMBOL(tty_unregister_device); | |
3661 | ||
3662 | struct tty_driver *alloc_tty_driver(int lines) | |
3663 | { | |
3664 | struct tty_driver *driver; | |
3665 | ||
3666 | driver = kmalloc(sizeof(struct tty_driver), GFP_KERNEL); | |
3667 | if (driver) { | |
3668 | memset(driver, 0, sizeof(struct tty_driver)); | |
3669 | driver->magic = TTY_DRIVER_MAGIC; | |
3670 | driver->num = lines; | |
3671 | /* later we'll move allocation of tables here */ | |
3672 | } | |
3673 | return driver; | |
3674 | } | |
3675 | ||
3676 | void put_tty_driver(struct tty_driver *driver) | |
3677 | { | |
3678 | kfree(driver); | |
3679 | } | |
3680 | ||
b68e31d0 JD |
3681 | void tty_set_operations(struct tty_driver *driver, |
3682 | const struct tty_operations *op) | |
1da177e4 LT |
3683 | { |
3684 | driver->open = op->open; | |
3685 | driver->close = op->close; | |
3686 | driver->write = op->write; | |
3687 | driver->put_char = op->put_char; | |
3688 | driver->flush_chars = op->flush_chars; | |
3689 | driver->write_room = op->write_room; | |
3690 | driver->chars_in_buffer = op->chars_in_buffer; | |
3691 | driver->ioctl = op->ioctl; | |
3692 | driver->set_termios = op->set_termios; | |
3693 | driver->throttle = op->throttle; | |
3694 | driver->unthrottle = op->unthrottle; | |
3695 | driver->stop = op->stop; | |
3696 | driver->start = op->start; | |
3697 | driver->hangup = op->hangup; | |
3698 | driver->break_ctl = op->break_ctl; | |
3699 | driver->flush_buffer = op->flush_buffer; | |
3700 | driver->set_ldisc = op->set_ldisc; | |
3701 | driver->wait_until_sent = op->wait_until_sent; | |
3702 | driver->send_xchar = op->send_xchar; | |
3703 | driver->read_proc = op->read_proc; | |
3704 | driver->write_proc = op->write_proc; | |
3705 | driver->tiocmget = op->tiocmget; | |
3706 | driver->tiocmset = op->tiocmset; | |
3707 | } | |
3708 | ||
3709 | ||
3710 | EXPORT_SYMBOL(alloc_tty_driver); | |
3711 | EXPORT_SYMBOL(put_tty_driver); | |
3712 | EXPORT_SYMBOL(tty_set_operations); | |
3713 | ||
3714 | /* | |
3715 | * Called by a tty driver to register itself. | |
3716 | */ | |
3717 | int tty_register_driver(struct tty_driver *driver) | |
3718 | { | |
3719 | int error; | |
3720 | int i; | |
3721 | dev_t dev; | |
3722 | void **p = NULL; | |
3723 | ||
3724 | if (driver->flags & TTY_DRIVER_INSTALLED) | |
3725 | return 0; | |
3726 | ||
543691a6 AW |
3727 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { |
3728 | p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); | |
1da177e4 LT |
3729 | if (!p) |
3730 | return -ENOMEM; | |
1da177e4 LT |
3731 | } |
3732 | ||
3733 | if (!driver->major) { | |
3734 | error = alloc_chrdev_region(&dev, driver->minor_start, driver->num, | |
e5717c48 | 3735 | driver->name); |
1da177e4 LT |
3736 | if (!error) { |
3737 | driver->major = MAJOR(dev); | |
3738 | driver->minor_start = MINOR(dev); | |
3739 | } | |
3740 | } else { | |
3741 | dev = MKDEV(driver->major, driver->minor_start); | |
e5717c48 | 3742 | error = register_chrdev_region(dev, driver->num, driver->name); |
1da177e4 LT |
3743 | } |
3744 | if (error < 0) { | |
3745 | kfree(p); | |
3746 | return error; | |
3747 | } | |
3748 | ||
3749 | if (p) { | |
3750 | driver->ttys = (struct tty_struct **)p; | |
edc6afc5 AC |
3751 | driver->termios = (struct ktermios **)(p + driver->num); |
3752 | driver->termios_locked = (struct ktermios **)(p + driver->num * 2); | |
1da177e4 LT |
3753 | } else { |
3754 | driver->ttys = NULL; | |
3755 | driver->termios = NULL; | |
3756 | driver->termios_locked = NULL; | |
3757 | } | |
3758 | ||
3759 | cdev_init(&driver->cdev, &tty_fops); | |
3760 | driver->cdev.owner = driver->owner; | |
3761 | error = cdev_add(&driver->cdev, dev, driver->num); | |
3762 | if (error) { | |
1da177e4 LT |
3763 | unregister_chrdev_region(dev, driver->num); |
3764 | driver->ttys = NULL; | |
3765 | driver->termios = driver->termios_locked = NULL; | |
3766 | kfree(p); | |
3767 | return error; | |
3768 | } | |
3769 | ||
3770 | if (!driver->put_char) | |
3771 | driver->put_char = tty_default_put_char; | |
3772 | ||
3773 | list_add(&driver->tty_drivers, &tty_drivers); | |
3774 | ||
331b8319 | 3775 | if ( !(driver->flags & TTY_DRIVER_DYNAMIC_DEV) ) { |
1da177e4 LT |
3776 | for(i = 0; i < driver->num; i++) |
3777 | tty_register_device(driver, i, NULL); | |
3778 | } | |
3779 | proc_tty_register_driver(driver); | |
3780 | return 0; | |
3781 | } | |
3782 | ||
3783 | EXPORT_SYMBOL(tty_register_driver); | |
3784 | ||
3785 | /* | |
3786 | * Called by a tty driver to unregister itself. | |
3787 | */ | |
3788 | int tty_unregister_driver(struct tty_driver *driver) | |
3789 | { | |
3790 | int i; | |
edc6afc5 | 3791 | struct ktermios *tp; |
1da177e4 LT |
3792 | void *p; |
3793 | ||
3794 | if (driver->refcount) | |
3795 | return -EBUSY; | |
3796 | ||
3797 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
3798 | driver->num); | |
3799 | ||
3800 | list_del(&driver->tty_drivers); | |
3801 | ||
3802 | /* | |
3803 | * Free the termios and termios_locked structures because | |
3804 | * we don't want to get memory leaks when modular tty | |
3805 | * drivers are removed from the kernel. | |
3806 | */ | |
3807 | for (i = 0; i < driver->num; i++) { | |
3808 | tp = driver->termios[i]; | |
3809 | if (tp) { | |
3810 | driver->termios[i] = NULL; | |
3811 | kfree(tp); | |
3812 | } | |
3813 | tp = driver->termios_locked[i]; | |
3814 | if (tp) { | |
3815 | driver->termios_locked[i] = NULL; | |
3816 | kfree(tp); | |
3817 | } | |
331b8319 | 3818 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
1da177e4 LT |
3819 | tty_unregister_device(driver, i); |
3820 | } | |
3821 | p = driver->ttys; | |
3822 | proc_tty_unregister_driver(driver); | |
3823 | driver->ttys = NULL; | |
3824 | driver->termios = driver->termios_locked = NULL; | |
3825 | kfree(p); | |
3826 | cdev_del(&driver->cdev); | |
3827 | return 0; | |
3828 | } | |
1da177e4 LT |
3829 | EXPORT_SYMBOL(tty_unregister_driver); |
3830 | ||
24ec839c PZ |
3831 | dev_t tty_devnum(struct tty_struct *tty) |
3832 | { | |
3833 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
3834 | } | |
3835 | EXPORT_SYMBOL(tty_devnum); | |
3836 | ||
3837 | void proc_clear_tty(struct task_struct *p) | |
3838 | { | |
3839 | spin_lock_irq(&p->sighand->siglock); | |
3840 | p->signal->tty = NULL; | |
3841 | spin_unlock_irq(&p->sighand->siglock); | |
3842 | } | |
24ec839c | 3843 | |
2a65f1d9 | 3844 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
3845 | { |
3846 | if (tty) { | |
d9c1e9a8 EB |
3847 | /* We should not have a session or pgrp to here but.... */ |
3848 | put_pid(tty->session); | |
3849 | put_pid(tty->pgrp); | |
ab521dc0 EB |
3850 | tty->session = get_pid(task_session(tsk)); |
3851 | tty->pgrp = get_pid(task_pgrp(tsk)); | |
24ec839c | 3852 | } |
2a65f1d9 | 3853 | put_pid(tsk->signal->tty_old_pgrp); |
24ec839c | 3854 | tsk->signal->tty = tty; |
ab521dc0 | 3855 | tsk->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
3856 | } |
3857 | ||
98a27ba4 | 3858 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
3859 | { |
3860 | spin_lock_irq(&tsk->sighand->siglock); | |
2a65f1d9 | 3861 | __proc_set_tty(tsk, tty); |
24ec839c PZ |
3862 | spin_unlock_irq(&tsk->sighand->siglock); |
3863 | } | |
3864 | ||
3865 | struct tty_struct *get_current_tty(void) | |
3866 | { | |
3867 | struct tty_struct *tty; | |
3868 | WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); | |
3869 | tty = current->signal->tty; | |
3870 | /* | |
3871 | * session->tty can be changed/cleared from under us, make sure we | |
3872 | * issue the load. The obtained pointer, when not NULL, is valid as | |
3873 | * long as we hold tty_mutex. | |
3874 | */ | |
3875 | barrier(); | |
3876 | return tty; | |
3877 | } | |
a311f743 | 3878 | EXPORT_SYMBOL_GPL(get_current_tty); |
1da177e4 LT |
3879 | |
3880 | /* | |
3881 | * Initialize the console device. This is called *early*, so | |
3882 | * we can't necessarily depend on lots of kernel help here. | |
3883 | * Just do some early initializations, and do the complex setup | |
3884 | * later. | |
3885 | */ | |
3886 | void __init console_init(void) | |
3887 | { | |
3888 | initcall_t *call; | |
3889 | ||
3890 | /* Setup the default TTY line discipline. */ | |
3891 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); | |
3892 | ||
3893 | /* | |
3894 | * set up the console device so that later boot sequences can | |
3895 | * inform about problems etc.. | |
3896 | */ | |
1da177e4 LT |
3897 | call = __con_initcall_start; |
3898 | while (call < __con_initcall_end) { | |
3899 | (*call)(); | |
3900 | call++; | |
3901 | } | |
3902 | } | |
3903 | ||
3904 | #ifdef CONFIG_VT | |
3905 | extern int vty_init(void); | |
3906 | #endif | |
3907 | ||
3908 | static int __init tty_class_init(void) | |
3909 | { | |
7fe845d1 | 3910 | tty_class = class_create(THIS_MODULE, "tty"); |
1da177e4 LT |
3911 | if (IS_ERR(tty_class)) |
3912 | return PTR_ERR(tty_class); | |
3913 | return 0; | |
3914 | } | |
3915 | ||
3916 | postcore_initcall(tty_class_init); | |
3917 | ||
3918 | /* 3/2004 jmc: why do these devices exist? */ | |
3919 | ||
3920 | static struct cdev tty_cdev, console_cdev; | |
3921 | #ifdef CONFIG_UNIX98_PTYS | |
3922 | static struct cdev ptmx_cdev; | |
3923 | #endif | |
3924 | #ifdef CONFIG_VT | |
3925 | static struct cdev vc0_cdev; | |
3926 | #endif | |
3927 | ||
3928 | /* | |
3929 | * Ok, now we can initialize the rest of the tty devices and can count | |
3930 | * on memory allocations, interrupts etc.. | |
3931 | */ | |
3932 | static int __init tty_init(void) | |
3933 | { | |
3934 | cdev_init(&tty_cdev, &tty_fops); | |
3935 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
3936 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
3937 | panic("Couldn't register /dev/tty driver\n"); | |
01107d34 | 3938 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty"); |
1da177e4 LT |
3939 | |
3940 | cdev_init(&console_cdev, &console_fops); | |
3941 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
3942 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
3943 | panic("Couldn't register /dev/console driver\n"); | |
01107d34 | 3944 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console"); |
1da177e4 LT |
3945 | |
3946 | #ifdef CONFIG_UNIX98_PTYS | |
3947 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
3948 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
3949 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
3950 | panic("Couldn't register /dev/ptmx driver\n"); | |
01107d34 | 3951 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); |
1da177e4 LT |
3952 | #endif |
3953 | ||
3954 | #ifdef CONFIG_VT | |
3955 | cdev_init(&vc0_cdev, &console_fops); | |
3956 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || | |
3957 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) | |
3958 | panic("Couldn't register /dev/tty0 driver\n"); | |
01107d34 | 3959 | device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); |
1da177e4 LT |
3960 | |
3961 | vty_init(); | |
3962 | #endif | |
3963 | return 0; | |
3964 | } | |
3965 | module_init(tty_init); |