Commit | Line | Data |
---|---|---|
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 | |
37bdfb07 | 22 | * makes for cleaner and more compact code. -TYT, 9/17/92 |
1da177e4 LT |
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 | |
37bdfb07 | 44 | * |
1da177e4 LT |
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. | |
37bdfb07 AC |
65 | * alloc_tty_struct() always uses kmalloc() |
66 | * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 | |
1da177e4 LT |
67 | */ |
68 | ||
1da177e4 LT |
69 | #include <linux/types.h> |
70 | #include <linux/major.h> | |
71 | #include <linux/errno.h> | |
72 | #include <linux/signal.h> | |
73 | #include <linux/fcntl.h> | |
74 | #include <linux/sched.h> | |
75 | #include <linux/interrupt.h> | |
76 | #include <linux/tty.h> | |
77 | #include <linux/tty_driver.h> | |
78 | #include <linux/tty_flip.h> | |
79 | #include <linux/devpts_fs.h> | |
80 | #include <linux/file.h> | |
81 | #include <linux/console.h> | |
82 | #include <linux/timer.h> | |
83 | #include <linux/ctype.h> | |
84 | #include <linux/kd.h> | |
85 | #include <linux/mm.h> | |
86 | #include <linux/string.h> | |
87 | #include <linux/slab.h> | |
88 | #include <linux/poll.h> | |
89 | #include <linux/proc_fs.h> | |
90 | #include <linux/init.h> | |
91 | #include <linux/module.h> | |
92 | #include <linux/smp_lock.h> | |
93 | #include <linux/device.h> | |
94 | #include <linux/idr.h> | |
95 | #include <linux/wait.h> | |
96 | #include <linux/bitops.h> | |
b20f3ae5 | 97 | #include <linux/delay.h> |
1da177e4 LT |
98 | |
99 | #include <asm/uaccess.h> | |
100 | #include <asm/system.h> | |
101 | ||
102 | #include <linux/kbd_kern.h> | |
103 | #include <linux/vt_kern.h> | |
104 | #include <linux/selection.h> | |
1da177e4 LT |
105 | |
106 | #include <linux/kmod.h> | |
b488893a | 107 | #include <linux/nsproxy.h> |
1da177e4 LT |
108 | |
109 | #undef TTY_DEBUG_HANGUP | |
110 | ||
111 | #define TTY_PARANOIA_CHECK 1 | |
112 | #define CHECK_TTY_COUNT 1 | |
113 | ||
edc6afc5 | 114 | struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ |
1da177e4 LT |
115 | .c_iflag = ICRNL | IXON, |
116 | .c_oflag = OPOST | ONLCR, | |
117 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, | |
118 | .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | | |
119 | ECHOCTL | ECHOKE | IEXTEN, | |
edc6afc5 AC |
120 | .c_cc = INIT_C_CC, |
121 | .c_ispeed = 38400, | |
122 | .c_ospeed = 38400 | |
1da177e4 LT |
123 | }; |
124 | ||
125 | EXPORT_SYMBOL(tty_std_termios); | |
126 | ||
127 | /* This list gets poked at by procfs and various bits of boot up code. This | |
128 | could do with some rationalisation such as pulling the tty proc function | |
129 | into this file */ | |
37bdfb07 | 130 | |
1da177e4 LT |
131 | LIST_HEAD(tty_drivers); /* linked list of tty drivers */ |
132 | ||
24ec839c | 133 | /* Mutex to protect creating and releasing a tty. This is shared with |
1da177e4 | 134 | vt.c for deeply disgusting hack reasons */ |
70522e12 | 135 | DEFINE_MUTEX(tty_mutex); |
de2a84f2 | 136 | EXPORT_SYMBOL(tty_mutex); |
1da177e4 LT |
137 | |
138 | #ifdef CONFIG_UNIX98_PTYS | |
139 | extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ | |
37bdfb07 | 140 | extern int pty_limit; /* Config limit on Unix98 ptys */ |
1da177e4 | 141 | static DEFINE_IDR(allocated_ptys); |
a6752f3f | 142 | static DEFINE_MUTEX(allocated_ptys_lock); |
1da177e4 LT |
143 | static int ptmx_open(struct inode *, struct file *); |
144 | #endif | |
145 | ||
1da177e4 LT |
146 | static void initialize_tty_struct(struct tty_struct *tty); |
147 | ||
148 | static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); | |
149 | static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); | |
37bdfb07 AC |
150 | ssize_t redirected_tty_write(struct file *, const char __user *, |
151 | size_t, loff_t *); | |
1da177e4 LT |
152 | static unsigned int tty_poll(struct file *, poll_table *); |
153 | static int tty_open(struct inode *, struct file *); | |
154 | static int tty_release(struct inode *, struct file *); | |
37bdfb07 | 155 | int tty_ioctl(struct inode *inode, struct file *file, |
1da177e4 | 156 | unsigned int cmd, unsigned long arg); |
e10cc1df | 157 | #ifdef CONFIG_COMPAT |
37bdfb07 | 158 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
e10cc1df PF |
159 | unsigned long arg); |
160 | #else | |
161 | #define tty_compat_ioctl NULL | |
162 | #endif | |
37bdfb07 | 163 | static int tty_fasync(int fd, struct file *filp, int on); |
d5698c28 | 164 | static void release_tty(struct tty_struct *tty, int idx); |
2a65f1d9 | 165 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
98a27ba4 | 166 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
1da177e4 | 167 | |
af9b897e AC |
168 | /** |
169 | * alloc_tty_struct - allocate a tty object | |
170 | * | |
171 | * Return a new empty tty structure. The data fields have not | |
172 | * been initialized in any way but has been zeroed | |
173 | * | |
174 | * Locking: none | |
af9b897e | 175 | */ |
1da177e4 LT |
176 | |
177 | static struct tty_struct *alloc_tty_struct(void) | |
178 | { | |
1266b1e1 | 179 | return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); |
1da177e4 LT |
180 | } |
181 | ||
33f0f88f AC |
182 | static void tty_buffer_free_all(struct tty_struct *); |
183 | ||
af9b897e AC |
184 | /** |
185 | * free_tty_struct - free a disused tty | |
186 | * @tty: tty struct to free | |
187 | * | |
188 | * Free the write buffers, tty queue and tty memory itself. | |
189 | * | |
190 | * Locking: none. Must be called after tty is definitely unused | |
191 | */ | |
192 | ||
1da177e4 LT |
193 | static inline void free_tty_struct(struct tty_struct *tty) |
194 | { | |
195 | kfree(tty->write_buf); | |
33f0f88f | 196 | tty_buffer_free_all(tty); |
1da177e4 LT |
197 | kfree(tty); |
198 | } | |
199 | ||
200 | #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) | |
201 | ||
af9b897e AC |
202 | /** |
203 | * tty_name - return tty naming | |
204 | * @tty: tty structure | |
205 | * @buf: buffer for output | |
206 | * | |
207 | * Convert a tty structure into a name. The name reflects the kernel | |
208 | * naming policy and if udev is in use may not reflect user space | |
209 | * | |
210 | * Locking: none | |
211 | */ | |
212 | ||
1da177e4 LT |
213 | char *tty_name(struct tty_struct *tty, char *buf) |
214 | { | |
215 | if (!tty) /* Hmm. NULL pointer. That's fun. */ | |
216 | strcpy(buf, "NULL tty"); | |
217 | else | |
218 | strcpy(buf, tty->name); | |
219 | return buf; | |
220 | } | |
221 | ||
222 | EXPORT_SYMBOL(tty_name); | |
223 | ||
d769a669 | 224 | int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, |
1da177e4 LT |
225 | const char *routine) |
226 | { | |
227 | #ifdef TTY_PARANOIA_CHECK | |
228 | if (!tty) { | |
229 | printk(KERN_WARNING | |
230 | "null TTY for (%d:%d) in %s\n", | |
231 | imajor(inode), iminor(inode), routine); | |
232 | return 1; | |
233 | } | |
234 | if (tty->magic != TTY_MAGIC) { | |
235 | printk(KERN_WARNING | |
236 | "bad magic number for tty struct (%d:%d) in %s\n", | |
237 | imajor(inode), iminor(inode), routine); | |
238 | return 1; | |
239 | } | |
240 | #endif | |
241 | return 0; | |
242 | } | |
243 | ||
244 | static int check_tty_count(struct tty_struct *tty, const char *routine) | |
245 | { | |
246 | #ifdef CHECK_TTY_COUNT | |
247 | struct list_head *p; | |
248 | int count = 0; | |
37bdfb07 | 249 | |
1da177e4 LT |
250 | file_list_lock(); |
251 | list_for_each(p, &tty->tty_files) { | |
252 | count++; | |
253 | } | |
254 | file_list_unlock(); | |
255 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
256 | tty->driver->subtype == PTY_TYPE_SLAVE && | |
257 | tty->link && tty->link->count) | |
258 | count++; | |
259 | if (tty->count != count) { | |
260 | printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " | |
261 | "!= #fd's(%d) in %s\n", | |
262 | tty->name, tty->count, count, routine); | |
263 | return count; | |
24ec839c | 264 | } |
1da177e4 LT |
265 | #endif |
266 | return 0; | |
267 | } | |
268 | ||
33f0f88f AC |
269 | /* |
270 | * Tty buffer allocation management | |
271 | */ | |
272 | ||
af9b897e AC |
273 | /** |
274 | * tty_buffer_free_all - free buffers used by a tty | |
275 | * @tty: tty to free from | |
276 | * | |
277 | * Remove all the buffers pending on a tty whether queued with data | |
278 | * or in the free ring. Must be called when the tty is no longer in use | |
279 | * | |
280 | * Locking: none | |
281 | */ | |
282 | ||
33f0f88f AC |
283 | static void tty_buffer_free_all(struct tty_struct *tty) |
284 | { | |
285 | struct tty_buffer *thead; | |
37bdfb07 | 286 | while ((thead = tty->buf.head) != NULL) { |
33f0f88f AC |
287 | tty->buf.head = thead->next; |
288 | kfree(thead); | |
289 | } | |
37bdfb07 | 290 | while ((thead = tty->buf.free) != NULL) { |
33f0f88f AC |
291 | tty->buf.free = thead->next; |
292 | kfree(thead); | |
293 | } | |
294 | tty->buf.tail = NULL; | |
01da5fd8 | 295 | tty->buf.memory_used = 0; |
33f0f88f AC |
296 | } |
297 | ||
01da5fd8 AC |
298 | /** |
299 | * tty_buffer_init - prepare a tty buffer structure | |
300 | * @tty: tty to initialise | |
301 | * | |
302 | * Set up the initial state of the buffer management for a tty device. | |
303 | * Must be called before the other tty buffer functions are used. | |
304 | * | |
305 | * Locking: none | |
306 | */ | |
307 | ||
33f0f88f AC |
308 | static void tty_buffer_init(struct tty_struct *tty) |
309 | { | |
808249ce | 310 | spin_lock_init(&tty->buf.lock); |
33f0f88f AC |
311 | tty->buf.head = NULL; |
312 | tty->buf.tail = NULL; | |
313 | tty->buf.free = NULL; | |
01da5fd8 | 314 | tty->buf.memory_used = 0; |
33f0f88f AC |
315 | } |
316 | ||
01da5fd8 AC |
317 | /** |
318 | * tty_buffer_alloc - allocate a tty buffer | |
319 | * @tty: tty device | |
320 | * @size: desired size (characters) | |
321 | * | |
322 | * Allocate a new tty buffer to hold the desired number of characters. | |
323 | * Return NULL if out of memory or the allocation would exceed the | |
324 | * per device queue | |
325 | * | |
326 | * Locking: Caller must hold tty->buf.lock | |
327 | */ | |
328 | ||
329 | static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) | |
33f0f88f | 330 | { |
01da5fd8 AC |
331 | struct tty_buffer *p; |
332 | ||
333 | if (tty->buf.memory_used + size > 65536) | |
334 | return NULL; | |
335 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); | |
37bdfb07 | 336 | if (p == NULL) |
33f0f88f AC |
337 | return NULL; |
338 | p->used = 0; | |
339 | p->size = size; | |
340 | p->next = NULL; | |
8977d929 PF |
341 | p->commit = 0; |
342 | p->read = 0; | |
33f0f88f AC |
343 | p->char_buf_ptr = (char *)(p->data); |
344 | p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; | |
01da5fd8 | 345 | tty->buf.memory_used += size; |
33f0f88f AC |
346 | return p; |
347 | } | |
348 | ||
01da5fd8 AC |
349 | /** |
350 | * tty_buffer_free - free a tty buffer | |
351 | * @tty: tty owning the buffer | |
352 | * @b: the buffer to free | |
353 | * | |
354 | * Free a tty buffer, or add it to the free list according to our | |
355 | * internal strategy | |
356 | * | |
357 | * Locking: Caller must hold tty->buf.lock | |
358 | */ | |
33f0f88f AC |
359 | |
360 | static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) | |
361 | { | |
362 | /* Dumb strategy for now - should keep some stats */ | |
01da5fd8 AC |
363 | tty->buf.memory_used -= b->size; |
364 | WARN_ON(tty->buf.memory_used < 0); | |
365 | ||
37bdfb07 | 366 | if (b->size >= 512) |
33f0f88f AC |
367 | kfree(b); |
368 | else { | |
369 | b->next = tty->buf.free; | |
370 | tty->buf.free = b; | |
371 | } | |
372 | } | |
373 | ||
c5c34d48 | 374 | /** |
42fd552e | 375 | * __tty_buffer_flush - flush full tty buffers |
c5c34d48 PF |
376 | * @tty: tty to flush |
377 | * | |
42fd552e AC |
378 | * flush all the buffers containing receive data. Caller must |
379 | * hold the buffer lock and must have ensured no parallel flush to | |
380 | * ldisc is running. | |
c5c34d48 | 381 | * |
42fd552e | 382 | * Locking: Caller must hold tty->buf.lock |
c5c34d48 PF |
383 | */ |
384 | ||
42fd552e | 385 | static void __tty_buffer_flush(struct tty_struct *tty) |
c5c34d48 PF |
386 | { |
387 | struct tty_buffer *thead; | |
c5c34d48 | 388 | |
37bdfb07 | 389 | while ((thead = tty->buf.head) != NULL) { |
c5c34d48 PF |
390 | tty->buf.head = thead->next; |
391 | tty_buffer_free(tty, thead); | |
392 | } | |
393 | tty->buf.tail = NULL; | |
42fd552e AC |
394 | } |
395 | ||
396 | /** | |
397 | * tty_buffer_flush - flush full tty buffers | |
398 | * @tty: tty to flush | |
399 | * | |
400 | * flush all the buffers containing receive data. If the buffer is | |
401 | * being processed by flush_to_ldisc then we defer the processing | |
402 | * to that function | |
403 | * | |
404 | * Locking: none | |
405 | */ | |
406 | ||
407 | static void tty_buffer_flush(struct tty_struct *tty) | |
408 | { | |
409 | unsigned long flags; | |
410 | spin_lock_irqsave(&tty->buf.lock, flags); | |
411 | ||
412 | /* If the data is being pushed to the tty layer then we can't | |
413 | process it here. Instead set a flag and the flush_to_ldisc | |
414 | path will process the flush request before it exits */ | |
415 | if (test_bit(TTY_FLUSHING, &tty->flags)) { | |
416 | set_bit(TTY_FLUSHPENDING, &tty->flags); | |
417 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
418 | wait_event(tty->read_wait, | |
419 | test_bit(TTY_FLUSHPENDING, &tty->flags) == 0); | |
420 | return; | |
421 | } else | |
422 | __tty_buffer_flush(tty); | |
c5c34d48 PF |
423 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
424 | } | |
425 | ||
01da5fd8 AC |
426 | /** |
427 | * tty_buffer_find - find a free tty buffer | |
428 | * @tty: tty owning the buffer | |
429 | * @size: characters wanted | |
430 | * | |
431 | * Locate an existing suitable tty buffer or if we are lacking one then | |
432 | * allocate a new one. We round our buffers off in 256 character chunks | |
433 | * to get better allocation behaviour. | |
434 | * | |
435 | * Locking: Caller must hold tty->buf.lock | |
436 | */ | |
437 | ||
33f0f88f AC |
438 | static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) |
439 | { | |
440 | struct tty_buffer **tbh = &tty->buf.free; | |
37bdfb07 | 441 | while ((*tbh) != NULL) { |
33f0f88f | 442 | struct tty_buffer *t = *tbh; |
37bdfb07 | 443 | if (t->size >= size) { |
33f0f88f AC |
444 | *tbh = t->next; |
445 | t->next = NULL; | |
446 | t->used = 0; | |
8977d929 PF |
447 | t->commit = 0; |
448 | t->read = 0; | |
01da5fd8 | 449 | tty->buf.memory_used += t->size; |
33f0f88f AC |
450 | return t; |
451 | } | |
452 | tbh = &((*tbh)->next); | |
453 | } | |
454 | /* Round the buffer size out */ | |
37bdfb07 | 455 | size = (size + 0xFF) & ~0xFF; |
01da5fd8 | 456 | return tty_buffer_alloc(tty, size); |
33f0f88f AC |
457 | /* Should possibly check if this fails for the largest buffer we |
458 | have queued and recycle that ? */ | |
459 | } | |
460 | ||
01da5fd8 AC |
461 | /** |
462 | * tty_buffer_request_room - grow tty buffer if needed | |
463 | * @tty: tty structure | |
464 | * @size: size desired | |
465 | * | |
466 | * Make at least size bytes of linear space available for the tty | |
467 | * buffer. If we fail return the size we managed to find. | |
468 | * | |
469 | * Locking: Takes tty->buf.lock | |
470 | */ | |
33f0f88f AC |
471 | int tty_buffer_request_room(struct tty_struct *tty, size_t size) |
472 | { | |
808249ce PF |
473 | struct tty_buffer *b, *n; |
474 | int left; | |
475 | unsigned long flags; | |
476 | ||
477 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33f0f88f AC |
478 | |
479 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to | |
480 | remove this conditional if its worth it. This would be invisible | |
481 | to the callers */ | |
33b37a33 | 482 | if ((b = tty->buf.tail) != NULL) |
33f0f88f | 483 | left = b->size - b->used; |
33b37a33 | 484 | else |
808249ce PF |
485 | left = 0; |
486 | ||
487 | if (left < size) { | |
488 | /* This is the slow path - looking for new buffers to use */ | |
489 | if ((n = tty_buffer_find(tty, size)) != NULL) { | |
490 | if (b != NULL) { | |
491 | b->next = n; | |
8977d929 | 492 | b->commit = b->used; |
808249ce PF |
493 | } else |
494 | tty->buf.head = n; | |
495 | tty->buf.tail = n; | |
808249ce PF |
496 | } else |
497 | size = left; | |
498 | } | |
499 | ||
500 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
33f0f88f AC |
501 | return size; |
502 | } | |
33f0f88f AC |
503 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
504 | ||
af9b897e AC |
505 | /** |
506 | * tty_insert_flip_string - Add characters to the tty buffer | |
507 | * @tty: tty structure | |
508 | * @chars: characters | |
509 | * @size: size | |
510 | * | |
511 | * Queue a series of bytes to the tty buffering. All the characters | |
512 | * passed are marked as without error. Returns the number added. | |
513 | * | |
514 | * Locking: Called functions may take tty->buf.lock | |
515 | */ | |
516 | ||
e1a25090 AM |
517 | int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, |
518 | size_t size) | |
33f0f88f AC |
519 | { |
520 | int copied = 0; | |
521 | do { | |
522 | int space = tty_buffer_request_room(tty, size - copied); | |
523 | struct tty_buffer *tb = tty->buf.tail; | |
524 | /* If there is no space then tb may be NULL */ | |
37bdfb07 | 525 | if (unlikely(space == 0)) |
33f0f88f AC |
526 | break; |
527 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
528 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
529 | tb->used += space; | |
530 | copied += space; | |
531 | chars += space; | |
527063ba AD |
532 | /* There is a small chance that we need to split the data over |
533 | several buffers. If this is the case we must loop */ | |
534 | } while (unlikely(size > copied)); | |
33f0f88f AC |
535 | return copied; |
536 | } | |
ee37df78 | 537 | EXPORT_SYMBOL(tty_insert_flip_string); |
33f0f88f | 538 | |
af9b897e AC |
539 | /** |
540 | * tty_insert_flip_string_flags - Add characters to the tty buffer | |
541 | * @tty: tty structure | |
542 | * @chars: characters | |
543 | * @flags: flag bytes | |
544 | * @size: size | |
545 | * | |
546 | * Queue a series of bytes to the tty buffering. For each character | |
547 | * the flags array indicates the status of the character. Returns the | |
548 | * number added. | |
549 | * | |
550 | * Locking: Called functions may take tty->buf.lock | |
551 | */ | |
552 | ||
e1a25090 AM |
553 | int tty_insert_flip_string_flags(struct tty_struct *tty, |
554 | const unsigned char *chars, const char *flags, size_t size) | |
33f0f88f AC |
555 | { |
556 | int copied = 0; | |
557 | do { | |
558 | int space = tty_buffer_request_room(tty, size - copied); | |
559 | struct tty_buffer *tb = tty->buf.tail; | |
560 | /* If there is no space then tb may be NULL */ | |
37bdfb07 | 561 | if (unlikely(space == 0)) |
33f0f88f AC |
562 | break; |
563 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
564 | memcpy(tb->flag_buf_ptr + tb->used, flags, space); | |
565 | tb->used += space; | |
566 | copied += space; | |
567 | chars += space; | |
568 | flags += space; | |
527063ba AD |
569 | /* There is a small chance that we need to split the data over |
570 | several buffers. If this is the case we must loop */ | |
571 | } while (unlikely(size > copied)); | |
33f0f88f AC |
572 | return copied; |
573 | } | |
ff4547f4 | 574 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
33f0f88f | 575 | |
af9b897e AC |
576 | /** |
577 | * tty_schedule_flip - push characters to ldisc | |
578 | * @tty: tty to push from | |
579 | * | |
580 | * Takes any pending buffers and transfers their ownership to the | |
581 | * ldisc side of the queue. It then schedules those characters for | |
582 | * processing by the line discipline. | |
583 | * | |
584 | * Locking: Takes tty->buf.lock | |
585 | */ | |
586 | ||
e1a25090 AM |
587 | void tty_schedule_flip(struct tty_struct *tty) |
588 | { | |
589 | unsigned long flags; | |
590 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 591 | if (tty->buf.tail != NULL) |
e1a25090 | 592 | tty->buf.tail->commit = tty->buf.tail->used; |
e1a25090 AM |
593 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
594 | schedule_delayed_work(&tty->buf.work, 1); | |
595 | } | |
596 | EXPORT_SYMBOL(tty_schedule_flip); | |
33f0f88f | 597 | |
af9b897e AC |
598 | /** |
599 | * tty_prepare_flip_string - make room for characters | |
600 | * @tty: tty | |
601 | * @chars: return pointer for character write area | |
602 | * @size: desired size | |
603 | * | |
33f0f88f AC |
604 | * Prepare a block of space in the buffer for data. Returns the length |
605 | * available and buffer pointer to the space which is now allocated and | |
606 | * accounted for as ready for normal characters. This is used for drivers | |
607 | * that need their own block copy routines into the buffer. There is no | |
608 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
609 | * |
610 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
611 | */ |
612 | ||
37bdfb07 AC |
613 | int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, |
614 | size_t size) | |
33f0f88f AC |
615 | { |
616 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
617 | if (likely(space)) { |
618 | struct tty_buffer *tb = tty->buf.tail; | |
619 | *chars = tb->char_buf_ptr + tb->used; | |
620 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
621 | tb->used += space; | |
622 | } | |
33f0f88f AC |
623 | return space; |
624 | } | |
625 | ||
626 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); | |
627 | ||
af9b897e AC |
628 | /** |
629 | * tty_prepare_flip_string_flags - make room for characters | |
630 | * @tty: tty | |
631 | * @chars: return pointer for character write area | |
632 | * @flags: return pointer for status flag write area | |
633 | * @size: desired size | |
634 | * | |
33f0f88f AC |
635 | * Prepare a block of space in the buffer for data. Returns the length |
636 | * available and buffer pointer to the space which is now allocated and | |
637 | * accounted for as ready for characters. This is used for drivers | |
638 | * that need their own block copy routines into the buffer. There is no | |
639 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
640 | * |
641 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
642 | */ |
643 | ||
37bdfb07 AC |
644 | int tty_prepare_flip_string_flags(struct tty_struct *tty, |
645 | unsigned char **chars, char **flags, size_t size) | |
33f0f88f AC |
646 | { |
647 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
648 | if (likely(space)) { |
649 | struct tty_buffer *tb = tty->buf.tail; | |
650 | *chars = tb->char_buf_ptr + tb->used; | |
651 | *flags = tb->flag_buf_ptr + tb->used; | |
652 | tb->used += space; | |
653 | } | |
33f0f88f AC |
654 | return space; |
655 | } | |
656 | ||
657 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); | |
658 | ||
659 | ||
660 | ||
af9b897e AC |
661 | /** |
662 | * tty_set_termios_ldisc - set ldisc field | |
663 | * @tty: tty structure | |
664 | * @num: line discipline number | |
665 | * | |
1da177e4 | 666 | * This is probably overkill for real world processors but |
37bdfb07 | 667 | * they are not on hot paths so a little discipline won't do |
1da177e4 | 668 | * any harm. |
af9b897e | 669 | * |
24ec839c | 670 | * Locking: takes termios_mutex |
1da177e4 | 671 | */ |
37bdfb07 | 672 | |
1da177e4 LT |
673 | static void tty_set_termios_ldisc(struct tty_struct *tty, int num) |
674 | { | |
5785c95b | 675 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 676 | tty->termios->c_line = num; |
5785c95b | 677 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
678 | } |
679 | ||
680 | /* | |
681 | * This guards the refcounted line discipline lists. The lock | |
682 | * must be taken with irqs off because there are hangup path | |
683 | * callers who will do ldisc lookups and cannot sleep. | |
684 | */ | |
37bdfb07 | 685 | |
1da177e4 LT |
686 | static DEFINE_SPINLOCK(tty_ldisc_lock); |
687 | static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); | |
37bdfb07 AC |
688 | /* Line disc dispatch table */ |
689 | static struct tty_ldisc tty_ldiscs[NR_LDISCS]; | |
1da177e4 | 690 | |
af9b897e AC |
691 | /** |
692 | * tty_register_ldisc - install a line discipline | |
693 | * @disc: ldisc number | |
694 | * @new_ldisc: pointer to the ldisc object | |
695 | * | |
696 | * Installs a new line discipline into the kernel. The discipline | |
697 | * is set up as unreferenced and then made available to the kernel | |
698 | * from this point onwards. | |
699 | * | |
700 | * Locking: | |
701 | * takes tty_ldisc_lock to guard against ldisc races | |
702 | */ | |
703 | ||
1da177e4 LT |
704 | int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) |
705 | { | |
706 | unsigned long flags; | |
707 | int ret = 0; | |
37bdfb07 | 708 | |
1da177e4 LT |
709 | if (disc < N_TTY || disc >= NR_LDISCS) |
710 | return -EINVAL; | |
37bdfb07 | 711 | |
1da177e4 | 712 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
bfb07599 AD |
713 | tty_ldiscs[disc] = *new_ldisc; |
714 | tty_ldiscs[disc].num = disc; | |
715 | tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; | |
716 | tty_ldiscs[disc].refcount = 0; | |
1da177e4 | 717 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
37bdfb07 | 718 | |
1da177e4 LT |
719 | return ret; |
720 | } | |
1da177e4 LT |
721 | EXPORT_SYMBOL(tty_register_ldisc); |
722 | ||
af9b897e AC |
723 | /** |
724 | * tty_unregister_ldisc - unload a line discipline | |
725 | * @disc: ldisc number | |
726 | * @new_ldisc: pointer to the ldisc object | |
727 | * | |
728 | * Remove a line discipline from the kernel providing it is not | |
729 | * currently in use. | |
730 | * | |
731 | * Locking: | |
732 | * takes tty_ldisc_lock to guard against ldisc races | |
733 | */ | |
734 | ||
bfb07599 AD |
735 | int tty_unregister_ldisc(int disc) |
736 | { | |
737 | unsigned long flags; | |
738 | int ret = 0; | |
739 | ||
740 | if (disc < N_TTY || disc >= NR_LDISCS) | |
741 | return -EINVAL; | |
742 | ||
743 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
744 | if (tty_ldiscs[disc].refcount) | |
745 | ret = -EBUSY; | |
746 | else | |
747 | tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; | |
748 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
749 | ||
750 | return ret; | |
751 | } | |
752 | EXPORT_SYMBOL(tty_unregister_ldisc); | |
753 | ||
af9b897e AC |
754 | /** |
755 | * tty_ldisc_get - take a reference to an ldisc | |
756 | * @disc: ldisc number | |
757 | * | |
758 | * Takes a reference to a line discipline. Deals with refcounts and | |
759 | * module locking counts. Returns NULL if the discipline is not available. | |
760 | * Returns a pointer to the discipline and bumps the ref count if it is | |
761 | * available | |
762 | * | |
763 | * Locking: | |
764 | * takes tty_ldisc_lock to guard against ldisc races | |
765 | */ | |
766 | ||
1da177e4 LT |
767 | struct tty_ldisc *tty_ldisc_get(int disc) |
768 | { | |
769 | unsigned long flags; | |
770 | struct tty_ldisc *ld; | |
771 | ||
772 | if (disc < N_TTY || disc >= NR_LDISCS) | |
773 | return NULL; | |
37bdfb07 | 774 | |
1da177e4 LT |
775 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
776 | ||
777 | ld = &tty_ldiscs[disc]; | |
778 | /* Check the entry is defined */ | |
37bdfb07 | 779 | if (ld->flags & LDISC_FLAG_DEFINED) { |
1da177e4 LT |
780 | /* If the module is being unloaded we can't use it */ |
781 | if (!try_module_get(ld->owner)) | |
37bdfb07 | 782 | ld = NULL; |
1da177e4 LT |
783 | else /* lock it */ |
784 | ld->refcount++; | |
37bdfb07 | 785 | } else |
1da177e4 LT |
786 | ld = NULL; |
787 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
788 | return ld; | |
789 | } | |
790 | ||
791 | EXPORT_SYMBOL_GPL(tty_ldisc_get); | |
792 | ||
af9b897e AC |
793 | /** |
794 | * tty_ldisc_put - drop ldisc reference | |
795 | * @disc: ldisc number | |
796 | * | |
797 | * Drop a reference to a line discipline. Manage refcounts and | |
798 | * module usage counts | |
799 | * | |
800 | * Locking: | |
801 | * takes tty_ldisc_lock to guard against ldisc races | |
802 | */ | |
803 | ||
1da177e4 LT |
804 | void tty_ldisc_put(int disc) |
805 | { | |
806 | struct tty_ldisc *ld; | |
807 | unsigned long flags; | |
37bdfb07 | 808 | |
56ee4827 | 809 | BUG_ON(disc < N_TTY || disc >= NR_LDISCS); |
37bdfb07 | 810 | |
1da177e4 LT |
811 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
812 | ld = &tty_ldiscs[disc]; | |
56ee4827 ES |
813 | BUG_ON(ld->refcount == 0); |
814 | ld->refcount--; | |
1da177e4 LT |
815 | module_put(ld->owner); |
816 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
817 | } | |
37bdfb07 | 818 | |
1da177e4 LT |
819 | EXPORT_SYMBOL_GPL(tty_ldisc_put); |
820 | ||
af9b897e AC |
821 | /** |
822 | * tty_ldisc_assign - set ldisc on a tty | |
823 | * @tty: tty to assign | |
824 | * @ld: line discipline | |
825 | * | |
826 | * Install an instance of a line discipline into a tty structure. The | |
827 | * ldisc must have a reference count above zero to ensure it remains/ | |
828 | * The tty instance refcount starts at zero. | |
829 | * | |
830 | * Locking: | |
831 | * Caller must hold references | |
832 | */ | |
833 | ||
1da177e4 LT |
834 | static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) |
835 | { | |
836 | tty->ldisc = *ld; | |
837 | tty->ldisc.refcount = 0; | |
838 | } | |
839 | ||
840 | /** | |
841 | * tty_ldisc_try - internal helper | |
842 | * @tty: the tty | |
843 | * | |
844 | * Make a single attempt to grab and bump the refcount on | |
845 | * the tty ldisc. Return 0 on failure or 1 on success. This is | |
846 | * used to implement both the waiting and non waiting versions | |
847 | * of tty_ldisc_ref | |
af9b897e AC |
848 | * |
849 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
850 | */ |
851 | ||
852 | static int tty_ldisc_try(struct tty_struct *tty) | |
853 | { | |
854 | unsigned long flags; | |
855 | struct tty_ldisc *ld; | |
856 | int ret = 0; | |
37bdfb07 | 857 | |
1da177e4 LT |
858 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
859 | ld = &tty->ldisc; | |
37bdfb07 | 860 | if (test_bit(TTY_LDISC, &tty->flags)) { |
1da177e4 LT |
861 | ld->refcount++; |
862 | ret = 1; | |
863 | } | |
864 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
865 | return ret; | |
866 | } | |
867 | ||
868 | /** | |
869 | * tty_ldisc_ref_wait - wait for the tty ldisc | |
870 | * @tty: tty device | |
871 | * | |
37bdfb07 AC |
872 | * Dereference the line discipline for the terminal and take a |
873 | * reference to it. If the line discipline is in flux then | |
1da177e4 LT |
874 | * wait patiently until it changes. |
875 | * | |
876 | * Note: Must not be called from an IRQ/timer context. The caller | |
877 | * must also be careful not to hold other locks that will deadlock | |
878 | * against a discipline change, such as an existing ldisc reference | |
879 | * (which we check for) | |
af9b897e AC |
880 | * |
881 | * Locking: call functions take tty_ldisc_lock | |
1da177e4 | 882 | */ |
37bdfb07 | 883 | |
1da177e4 LT |
884 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) |
885 | { | |
886 | /* wait_event is a macro */ | |
887 | wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); | |
37bdfb07 | 888 | if (tty->ldisc.refcount == 0) |
1da177e4 LT |
889 | printk(KERN_ERR "tty_ldisc_ref_wait\n"); |
890 | return &tty->ldisc; | |
891 | } | |
892 | ||
893 | EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); | |
894 | ||
895 | /** | |
896 | * tty_ldisc_ref - get the tty ldisc | |
897 | * @tty: tty device | |
898 | * | |
37bdfb07 AC |
899 | * Dereference the line discipline for the terminal and take a |
900 | * reference to it. If the line discipline is in flux then | |
1da177e4 | 901 | * return NULL. Can be called from IRQ and timer functions. |
af9b897e AC |
902 | * |
903 | * Locking: called functions take tty_ldisc_lock | |
1da177e4 | 904 | */ |
37bdfb07 | 905 | |
1da177e4 LT |
906 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) |
907 | { | |
37bdfb07 | 908 | if (tty_ldisc_try(tty)) |
1da177e4 LT |
909 | return &tty->ldisc; |
910 | return NULL; | |
911 | } | |
912 | ||
913 | EXPORT_SYMBOL_GPL(tty_ldisc_ref); | |
914 | ||
915 | /** | |
916 | * tty_ldisc_deref - free a tty ldisc reference | |
917 | * @ld: reference to free up | |
918 | * | |
919 | * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May | |
920 | * be called in IRQ context. | |
af9b897e AC |
921 | * |
922 | * Locking: takes tty_ldisc_lock | |
1da177e4 | 923 | */ |
37bdfb07 | 924 | |
1da177e4 LT |
925 | void tty_ldisc_deref(struct tty_ldisc *ld) |
926 | { | |
927 | unsigned long flags; | |
928 | ||
56ee4827 | 929 | BUG_ON(ld == NULL); |
37bdfb07 | 930 | |
1da177e4 | 931 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
37bdfb07 | 932 | if (ld->refcount == 0) |
1da177e4 LT |
933 | printk(KERN_ERR "tty_ldisc_deref: no references.\n"); |
934 | else | |
935 | ld->refcount--; | |
37bdfb07 | 936 | if (ld->refcount == 0) |
1da177e4 LT |
937 | wake_up(&tty_ldisc_wait); |
938 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
939 | } | |
940 | ||
941 | EXPORT_SYMBOL_GPL(tty_ldisc_deref); | |
942 | ||
943 | /** | |
944 | * tty_ldisc_enable - allow ldisc use | |
945 | * @tty: terminal to activate ldisc on | |
946 | * | |
947 | * Set the TTY_LDISC flag when the line discipline can be called | |
3a4fa0a2 | 948 | * again. Do necessary wakeups for existing sleepers. |
1da177e4 LT |
949 | * |
950 | * Note: nobody should set this bit except via this function. Clearing | |
951 | * directly is allowed. | |
952 | */ | |
953 | ||
954 | static void tty_ldisc_enable(struct tty_struct *tty) | |
955 | { | |
956 | set_bit(TTY_LDISC, &tty->flags); | |
957 | wake_up(&tty_ldisc_wait); | |
958 | } | |
37bdfb07 | 959 | |
1da177e4 LT |
960 | /** |
961 | * tty_set_ldisc - set line discipline | |
962 | * @tty: the terminal to set | |
963 | * @ldisc: the line discipline | |
964 | * | |
965 | * Set the discipline of a tty line. Must be called from a process | |
966 | * context. | |
af9b897e AC |
967 | * |
968 | * Locking: takes tty_ldisc_lock. | |
24ec839c | 969 | * called functions take termios_mutex |
1da177e4 | 970 | */ |
37bdfb07 | 971 | |
1da177e4 LT |
972 | static int tty_set_ldisc(struct tty_struct *tty, int ldisc) |
973 | { | |
ff55fe20 JB |
974 | int retval = 0; |
975 | struct tty_ldisc o_ldisc; | |
1da177e4 LT |
976 | char buf[64]; |
977 | int work; | |
978 | unsigned long flags; | |
979 | struct tty_ldisc *ld; | |
ff55fe20 | 980 | struct tty_struct *o_tty; |
1da177e4 LT |
981 | |
982 | if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) | |
983 | return -EINVAL; | |
984 | ||
985 | restart: | |
986 | ||
1da177e4 LT |
987 | ld = tty_ldisc_get(ldisc); |
988 | /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ | |
989 | /* Cyrus Durgin <cider@speakeasy.org> */ | |
990 | if (ld == NULL) { | |
991 | request_module("tty-ldisc-%d", ldisc); | |
992 | ld = tty_ldisc_get(ldisc); | |
993 | } | |
994 | if (ld == NULL) | |
995 | return -EINVAL; | |
996 | ||
33f0f88f AC |
997 | /* |
998 | * Problem: What do we do if this blocks ? | |
999 | */ | |
1000 | ||
1da177e4 LT |
1001 | tty_wait_until_sent(tty, 0); |
1002 | ||
ff55fe20 JB |
1003 | if (tty->ldisc.num == ldisc) { |
1004 | tty_ldisc_put(ldisc); | |
1005 | return 0; | |
1006 | } | |
1007 | ||
ae030e43 PF |
1008 | /* |
1009 | * No more input please, we are switching. The new ldisc | |
1010 | * will update this value in the ldisc open function | |
1011 | */ | |
1012 | ||
1013 | tty->receive_room = 0; | |
1014 | ||
ff55fe20 JB |
1015 | o_ldisc = tty->ldisc; |
1016 | o_tty = tty->link; | |
1017 | ||
1da177e4 LT |
1018 | /* |
1019 | * Make sure we don't change while someone holds a | |
1020 | * reference to the line discipline. The TTY_LDISC bit | |
1021 | * prevents anyone taking a reference once it is clear. | |
1022 | * We need the lock to avoid racing reference takers. | |
1023 | */ | |
ff55fe20 | 1024 | |
1da177e4 | 1025 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
ff55fe20 | 1026 | if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { |
37bdfb07 | 1027 | if (tty->ldisc.refcount) { |
ff55fe20 JB |
1028 | /* Free the new ldisc we grabbed. Must drop the lock |
1029 | first. */ | |
1030 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
1031 | tty_ldisc_put(ldisc); | |
1032 | /* | |
1033 | * There are several reasons we may be busy, including | |
1034 | * random momentary I/O traffic. We must therefore | |
1035 | * retry. We could distinguish between blocking ops | |
37bdfb07 AC |
1036 | * and retries if we made tty_ldisc_wait() smarter. |
1037 | * That is up for discussion. | |
ff55fe20 JB |
1038 | */ |
1039 | if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) | |
1040 | return -ERESTARTSYS; | |
1041 | goto restart; | |
1042 | } | |
37bdfb07 | 1043 | if (o_tty && o_tty->ldisc.refcount) { |
ff55fe20 JB |
1044 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
1045 | tty_ldisc_put(ldisc); | |
1046 | if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) | |
1047 | return -ERESTARTSYS; | |
1048 | goto restart; | |
1049 | } | |
1050 | } | |
37bdfb07 AC |
1051 | /* |
1052 | * If the TTY_LDISC bit is set, then we are racing against | |
1053 | * another ldisc change | |
1054 | */ | |
ff55fe20 | 1055 | if (!test_bit(TTY_LDISC, &tty->flags)) { |
1da177e4 LT |
1056 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
1057 | tty_ldisc_put(ldisc); | |
ff55fe20 JB |
1058 | ld = tty_ldisc_ref_wait(tty); |
1059 | tty_ldisc_deref(ld); | |
1da177e4 LT |
1060 | goto restart; |
1061 | } | |
ff55fe20 JB |
1062 | |
1063 | clear_bit(TTY_LDISC, &tty->flags); | |
817d6d3b | 1064 | if (o_tty) |
ff55fe20 | 1065 | clear_bit(TTY_LDISC, &o_tty->flags); |
1da177e4 | 1066 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
ff55fe20 | 1067 | |
1da177e4 LT |
1068 | /* |
1069 | * From this point on we know nobody has an ldisc | |
1070 | * usage reference, nor can they obtain one until | |
1071 | * we say so later on. | |
1072 | */ | |
ff55fe20 | 1073 | |
33f0f88f | 1074 | work = cancel_delayed_work(&tty->buf.work); |
1da177e4 | 1075 | /* |
33f0f88f | 1076 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 | 1077 | */ |
1da177e4 LT |
1078 | flush_scheduled_work(); |
1079 | /* Shutdown the current discipline. */ | |
1080 | if (tty->ldisc.close) | |
1081 | (tty->ldisc.close)(tty); | |
1082 | ||
1083 | /* Now set up the new line discipline. */ | |
1084 | tty_ldisc_assign(tty, ld); | |
1085 | tty_set_termios_ldisc(tty, ldisc); | |
1086 | if (tty->ldisc.open) | |
1087 | retval = (tty->ldisc.open)(tty); | |
1088 | if (retval < 0) { | |
1089 | tty_ldisc_put(ldisc); | |
1090 | /* There is an outstanding reference here so this is safe */ | |
1091 | tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); | |
1092 | tty_set_termios_ldisc(tty, tty->ldisc.num); | |
1093 | if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { | |
1094 | tty_ldisc_put(o_ldisc.num); | |
1095 | /* This driver is always present */ | |
1096 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
1097 | tty_set_termios_ldisc(tty, N_TTY); | |
1098 | if (tty->ldisc.open) { | |
1099 | int r = tty->ldisc.open(tty); | |
1100 | ||
1101 | if (r < 0) | |
1102 | panic("Couldn't open N_TTY ldisc for " | |
1103 | "%s --- error %d.", | |
1104 | tty_name(tty, buf), r); | |
1105 | } | |
1106 | } | |
1107 | } | |
1108 | /* At this point we hold a reference to the new ldisc and a | |
1109 | a reference to the old ldisc. If we ended up flipping back | |
1110 | to the existing ldisc we have two references to it */ | |
37bdfb07 | 1111 | |
1da177e4 LT |
1112 | if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) |
1113 | tty->driver->set_ldisc(tty); | |
37bdfb07 | 1114 | |
1da177e4 | 1115 | tty_ldisc_put(o_ldisc.num); |
37bdfb07 | 1116 | |
1da177e4 LT |
1117 | /* |
1118 | * Allow ldisc referencing to occur as soon as the driver | |
1119 | * ldisc callback completes. | |
1120 | */ | |
37bdfb07 | 1121 | |
1da177e4 | 1122 | tty_ldisc_enable(tty); |
ff55fe20 JB |
1123 | if (o_tty) |
1124 | tty_ldisc_enable(o_tty); | |
37bdfb07 | 1125 | |
1da177e4 LT |
1126 | /* Restart it in case no characters kick it off. Safe if |
1127 | already running */ | |
ff55fe20 | 1128 | if (work) |
33f0f88f | 1129 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
1130 | return retval; |
1131 | } | |
1132 | ||
af9b897e AC |
1133 | /** |
1134 | * get_tty_driver - find device of a tty | |
1135 | * @dev_t: device identifier | |
1136 | * @index: returns the index of the tty | |
1137 | * | |
1138 | * This routine returns a tty driver structure, given a device number | |
1139 | * and also passes back the index number. | |
1140 | * | |
1141 | * Locking: caller must hold tty_mutex | |
1da177e4 | 1142 | */ |
af9b897e | 1143 | |
1da177e4 LT |
1144 | static struct tty_driver *get_tty_driver(dev_t device, int *index) |
1145 | { | |
1146 | struct tty_driver *p; | |
1147 | ||
1148 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1149 | dev_t base = MKDEV(p->major, p->minor_start); | |
1150 | if (device < base || device >= base + p->num) | |
1151 | continue; | |
1152 | *index = device - base; | |
1153 | return p; | |
1154 | } | |
1155 | return NULL; | |
1156 | } | |
1157 | ||
af9b897e AC |
1158 | /** |
1159 | * tty_check_change - check for POSIX terminal changes | |
1160 | * @tty: tty to check | |
1161 | * | |
1162 | * If we try to write to, or set the state of, a terminal and we're | |
1163 | * not in the foreground, send a SIGTTOU. If the signal is blocked or | |
1164 | * ignored, go ahead and perform the operation. (POSIX 7.2) | |
1165 | * | |
1166 | * Locking: none | |
1da177e4 | 1167 | */ |
af9b897e | 1168 | |
37bdfb07 | 1169 | int tty_check_change(struct tty_struct *tty) |
1da177e4 LT |
1170 | { |
1171 | if (current->signal->tty != tty) | |
1172 | return 0; | |
ab521dc0 EB |
1173 | if (!tty->pgrp) { |
1174 | printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n"); | |
1da177e4 LT |
1175 | return 0; |
1176 | } | |
ab521dc0 | 1177 | if (task_pgrp(current) == tty->pgrp) |
1da177e4 LT |
1178 | return 0; |
1179 | if (is_ignored(SIGTTOU)) | |
1180 | return 0; | |
3e7cd6c4 | 1181 | if (is_current_pgrp_orphaned()) |
1da177e4 | 1182 | return -EIO; |
040b6362 ON |
1183 | kill_pgrp(task_pgrp(current), SIGTTOU, 1); |
1184 | set_thread_flag(TIF_SIGPENDING); | |
1da177e4 LT |
1185 | return -ERESTARTSYS; |
1186 | } | |
1187 | ||
1188 | EXPORT_SYMBOL(tty_check_change); | |
1189 | ||
37bdfb07 | 1190 | static ssize_t hung_up_tty_read(struct file *file, char __user *buf, |
1da177e4 LT |
1191 | size_t count, loff_t *ppos) |
1192 | { | |
1193 | return 0; | |
1194 | } | |
1195 | ||
37bdfb07 | 1196 | static ssize_t hung_up_tty_write(struct file *file, const char __user *buf, |
1da177e4 LT |
1197 | size_t count, loff_t *ppos) |
1198 | { | |
1199 | return -EIO; | |
1200 | } | |
1201 | ||
1202 | /* No kernel lock held - none needed ;) */ | |
37bdfb07 | 1203 | static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait) |
1da177e4 LT |
1204 | { |
1205 | return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; | |
1206 | } | |
1207 | ||
37bdfb07 | 1208 | static int hung_up_tty_ioctl(struct inode *inode, struct file *file, |
38ad2ed0 PF |
1209 | unsigned int cmd, unsigned long arg) |
1210 | { | |
1211 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1212 | } | |
1213 | ||
37bdfb07 | 1214 | static long hung_up_tty_compat_ioctl(struct file *file, |
38ad2ed0 | 1215 | unsigned int cmd, unsigned long arg) |
1da177e4 LT |
1216 | { |
1217 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1218 | } | |
1219 | ||
62322d25 | 1220 | static const struct file_operations tty_fops = { |
1da177e4 LT |
1221 | .llseek = no_llseek, |
1222 | .read = tty_read, | |
1223 | .write = tty_write, | |
1224 | .poll = tty_poll, | |
1225 | .ioctl = tty_ioctl, | |
e10cc1df | 1226 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1227 | .open = tty_open, |
1228 | .release = tty_release, | |
1229 | .fasync = tty_fasync, | |
1230 | }; | |
1231 | ||
1232 | #ifdef CONFIG_UNIX98_PTYS | |
62322d25 | 1233 | static const struct file_operations ptmx_fops = { |
1da177e4 LT |
1234 | .llseek = no_llseek, |
1235 | .read = tty_read, | |
1236 | .write = tty_write, | |
1237 | .poll = tty_poll, | |
1238 | .ioctl = tty_ioctl, | |
e10cc1df | 1239 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1240 | .open = ptmx_open, |
1241 | .release = tty_release, | |
1242 | .fasync = tty_fasync, | |
1243 | }; | |
1244 | #endif | |
1245 | ||
62322d25 | 1246 | static const struct file_operations console_fops = { |
1da177e4 LT |
1247 | .llseek = no_llseek, |
1248 | .read = tty_read, | |
1249 | .write = redirected_tty_write, | |
1250 | .poll = tty_poll, | |
1251 | .ioctl = tty_ioctl, | |
e10cc1df | 1252 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1253 | .open = tty_open, |
1254 | .release = tty_release, | |
1255 | .fasync = tty_fasync, | |
1256 | }; | |
1257 | ||
62322d25 | 1258 | static const struct file_operations hung_up_tty_fops = { |
1da177e4 LT |
1259 | .llseek = no_llseek, |
1260 | .read = hung_up_tty_read, | |
1261 | .write = hung_up_tty_write, | |
1262 | .poll = hung_up_tty_poll, | |
38ad2ed0 PF |
1263 | .ioctl = hung_up_tty_ioctl, |
1264 | .compat_ioctl = hung_up_tty_compat_ioctl, | |
1da177e4 LT |
1265 | .release = tty_release, |
1266 | }; | |
1267 | ||
1268 | static DEFINE_SPINLOCK(redirect_lock); | |
1269 | static struct file *redirect; | |
1270 | ||
1271 | /** | |
1272 | * tty_wakeup - request more data | |
1273 | * @tty: terminal | |
1274 | * | |
1275 | * Internal and external helper for wakeups of tty. This function | |
1276 | * informs the line discipline if present that the driver is ready | |
1277 | * to receive more output data. | |
1278 | */ | |
37bdfb07 | 1279 | |
1da177e4 LT |
1280 | void tty_wakeup(struct tty_struct *tty) |
1281 | { | |
1282 | struct tty_ldisc *ld; | |
37bdfb07 | 1283 | |
1da177e4 LT |
1284 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { |
1285 | ld = tty_ldisc_ref(tty); | |
37bdfb07 AC |
1286 | if (ld) { |
1287 | if (ld->write_wakeup) | |
1da177e4 LT |
1288 | ld->write_wakeup(tty); |
1289 | tty_ldisc_deref(ld); | |
1290 | } | |
1291 | } | |
1292 | wake_up_interruptible(&tty->write_wait); | |
1293 | } | |
1294 | ||
1295 | EXPORT_SYMBOL_GPL(tty_wakeup); | |
1296 | ||
1297 | /** | |
1298 | * tty_ldisc_flush - flush line discipline queue | |
1299 | * @tty: tty | |
1300 | * | |
1301 | * Flush the line discipline queue (if any) for this tty. If there | |
1302 | * is no line discipline active this is a no-op. | |
1303 | */ | |
37bdfb07 | 1304 | |
1da177e4 LT |
1305 | void tty_ldisc_flush(struct tty_struct *tty) |
1306 | { | |
1307 | struct tty_ldisc *ld = tty_ldisc_ref(tty); | |
37bdfb07 AC |
1308 | if (ld) { |
1309 | if (ld->flush_buffer) | |
1da177e4 LT |
1310 | ld->flush_buffer(tty); |
1311 | tty_ldisc_deref(ld); | |
1312 | } | |
c5c34d48 | 1313 | tty_buffer_flush(tty); |
1da177e4 LT |
1314 | } |
1315 | ||
1316 | EXPORT_SYMBOL_GPL(tty_ldisc_flush); | |
edc6afc5 AC |
1317 | |
1318 | /** | |
1319 | * tty_reset_termios - reset terminal state | |
1320 | * @tty: tty to reset | |
1321 | * | |
1322 | * Restore a terminal to the driver default state | |
1323 | */ | |
1324 | ||
1325 | static void tty_reset_termios(struct tty_struct *tty) | |
1326 | { | |
1327 | mutex_lock(&tty->termios_mutex); | |
1328 | *tty->termios = tty->driver->init_termios; | |
1329 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
1330 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1331 | mutex_unlock(&tty->termios_mutex); | |
1332 | } | |
37bdfb07 | 1333 | |
af9b897e AC |
1334 | /** |
1335 | * do_tty_hangup - actual handler for hangup events | |
65f27f38 | 1336 | * @work: tty device |
af9b897e AC |
1337 | * |
1338 | * This can be called by the "eventd" kernel thread. That is process | |
1339 | * synchronous but doesn't hold any locks, so we need to make sure we | |
1340 | * have the appropriate locks for what we're doing. | |
1341 | * | |
1342 | * The hangup event clears any pending redirections onto the hung up | |
1343 | * device. It ensures future writes will error and it does the needed | |
1344 | * line discipline hangup and signal delivery. The tty object itself | |
1345 | * remains intact. | |
1346 | * | |
1347 | * Locking: | |
1348 | * BKL | |
24ec839c PZ |
1349 | * redirect lock for undoing redirection |
1350 | * file list lock for manipulating list of ttys | |
1351 | * tty_ldisc_lock from called functions | |
1352 | * termios_mutex resetting termios data | |
1353 | * tasklist_lock to walk task list for hangup event | |
1354 | * ->siglock to protect ->signal/->sighand | |
1da177e4 | 1355 | */ |
65f27f38 | 1356 | static void do_tty_hangup(struct work_struct *work) |
1da177e4 | 1357 | { |
65f27f38 DH |
1358 | struct tty_struct *tty = |
1359 | container_of(work, struct tty_struct, hangup_work); | |
37bdfb07 | 1360 | struct file *cons_filp = NULL; |
1da177e4 LT |
1361 | struct file *filp, *f = NULL; |
1362 | struct task_struct *p; | |
1363 | struct tty_ldisc *ld; | |
1364 | int closecount = 0, n; | |
1365 | ||
1366 | if (!tty) | |
1367 | return; | |
1368 | ||
1369 | /* inuse_filps is protected by the single kernel lock */ | |
1370 | lock_kernel(); | |
1371 | ||
1372 | spin_lock(&redirect_lock); | |
1373 | if (redirect && redirect->private_data == tty) { | |
1374 | f = redirect; | |
1375 | redirect = NULL; | |
1376 | } | |
1377 | spin_unlock(&redirect_lock); | |
37bdfb07 | 1378 | |
1da177e4 LT |
1379 | check_tty_count(tty, "do_tty_hangup"); |
1380 | file_list_lock(); | |
1381 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ | |
2f512016 | 1382 | list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { |
1da177e4 LT |
1383 | if (filp->f_op->write == redirected_tty_write) |
1384 | cons_filp = filp; | |
1385 | if (filp->f_op->write != tty_write) | |
1386 | continue; | |
1387 | closecount++; | |
1388 | tty_fasync(-1, filp, 0); /* can't block */ | |
1389 | filp->f_op = &hung_up_tty_fops; | |
1390 | } | |
1391 | file_list_unlock(); | |
37bdfb07 AC |
1392 | /* |
1393 | * FIXME! What are the locking issues here? This may me overdoing | |
1394 | * things... This question is especially important now that we've | |
1395 | * removed the irqlock. | |
1396 | */ | |
1da177e4 | 1397 | ld = tty_ldisc_ref(tty); |
37bdfb07 AC |
1398 | if (ld != NULL) { |
1399 | /* We may have no line discipline at this point */ | |
1da177e4 LT |
1400 | if (ld->flush_buffer) |
1401 | ld->flush_buffer(tty); | |
1402 | if (tty->driver->flush_buffer) | |
1403 | tty->driver->flush_buffer(tty); | |
1404 | if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && | |
1405 | ld->write_wakeup) | |
1406 | ld->write_wakeup(tty); | |
1407 | if (ld->hangup) | |
1408 | ld->hangup(tty); | |
1409 | } | |
37bdfb07 AC |
1410 | /* |
1411 | * FIXME: Once we trust the LDISC code better we can wait here for | |
1412 | * ldisc completion and fix the driver call race | |
1413 | */ | |
1da177e4 LT |
1414 | wake_up_interruptible(&tty->write_wait); |
1415 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1416 | /* |
1417 | * Shutdown the current line discipline, and reset it to | |
1418 | * N_TTY. | |
1419 | */ | |
1420 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
edc6afc5 | 1421 | tty_reset_termios(tty); |
1da177e4 LT |
1422 | /* Defer ldisc switch */ |
1423 | /* tty_deferred_ldisc_switch(N_TTY); | |
37bdfb07 | 1424 | |
1da177e4 LT |
1425 | This should get done automatically when the port closes and |
1426 | tty_release is called */ | |
37bdfb07 | 1427 | |
1da177e4 | 1428 | read_lock(&tasklist_lock); |
ab521dc0 EB |
1429 | if (tty->session) { |
1430 | do_each_pid_task(tty->session, PIDTYPE_SID, p) { | |
24ec839c | 1431 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
1432 | if (p->signal->tty == tty) |
1433 | p->signal->tty = NULL; | |
24ec839c PZ |
1434 | if (!p->signal->leader) { |
1435 | spin_unlock_irq(&p->sighand->siglock); | |
1da177e4 | 1436 | continue; |
24ec839c PZ |
1437 | } |
1438 | __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); | |
1439 | __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); | |
ab521dc0 EB |
1440 | put_pid(p->signal->tty_old_pgrp); /* A noop */ |
1441 | if (tty->pgrp) | |
1442 | p->signal->tty_old_pgrp = get_pid(tty->pgrp); | |
24ec839c | 1443 | spin_unlock_irq(&p->sighand->siglock); |
ab521dc0 | 1444 | } while_each_pid_task(tty->session, PIDTYPE_SID, p); |
1da177e4 LT |
1445 | } |
1446 | read_unlock(&tasklist_lock); | |
1447 | ||
1448 | tty->flags = 0; | |
d9c1e9a8 EB |
1449 | put_pid(tty->session); |
1450 | put_pid(tty->pgrp); | |
ab521dc0 EB |
1451 | tty->session = NULL; |
1452 | tty->pgrp = NULL; | |
1da177e4 LT |
1453 | tty->ctrl_status = 0; |
1454 | /* | |
37bdfb07 AC |
1455 | * If one of the devices matches a console pointer, we |
1456 | * cannot just call hangup() because that will cause | |
1457 | * tty->count and state->count to go out of sync. | |
1458 | * So we just call close() the right number of times. | |
1da177e4 LT |
1459 | */ |
1460 | if (cons_filp) { | |
1461 | if (tty->driver->close) | |
1462 | for (n = 0; n < closecount; n++) | |
1463 | tty->driver->close(tty, cons_filp); | |
1464 | } else if (tty->driver->hangup) | |
1465 | (tty->driver->hangup)(tty); | |
37bdfb07 AC |
1466 | /* |
1467 | * We don't want to have driver/ldisc interactions beyond | |
1468 | * the ones we did here. The driver layer expects no | |
1469 | * calls after ->hangup() from the ldisc side. However we | |
1470 | * can't yet guarantee all that. | |
1471 | */ | |
1da177e4 LT |
1472 | set_bit(TTY_HUPPED, &tty->flags); |
1473 | if (ld) { | |
1474 | tty_ldisc_enable(tty); | |
1475 | tty_ldisc_deref(ld); | |
1476 | } | |
1477 | unlock_kernel(); | |
1478 | if (f) | |
1479 | fput(f); | |
1480 | } | |
1481 | ||
af9b897e AC |
1482 | /** |
1483 | * tty_hangup - trigger a hangup event | |
1484 | * @tty: tty to hangup | |
1485 | * | |
1486 | * A carrier loss (virtual or otherwise) has occurred on this like | |
1487 | * schedule a hangup sequence to run after this event. | |
1488 | */ | |
1489 | ||
37bdfb07 | 1490 | void tty_hangup(struct tty_struct *tty) |
1da177e4 LT |
1491 | { |
1492 | #ifdef TTY_DEBUG_HANGUP | |
1493 | char buf[64]; | |
1da177e4 LT |
1494 | printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); |
1495 | #endif | |
1496 | schedule_work(&tty->hangup_work); | |
1497 | } | |
1498 | ||
1499 | EXPORT_SYMBOL(tty_hangup); | |
1500 | ||
af9b897e AC |
1501 | /** |
1502 | * tty_vhangup - process vhangup | |
1503 | * @tty: tty to hangup | |
1504 | * | |
1505 | * The user has asked via system call for the terminal to be hung up. | |
1506 | * We do this synchronously so that when the syscall returns the process | |
3a4fa0a2 | 1507 | * is complete. That guarantee is necessary for security reasons. |
af9b897e AC |
1508 | */ |
1509 | ||
37bdfb07 | 1510 | void tty_vhangup(struct tty_struct *tty) |
1da177e4 LT |
1511 | { |
1512 | #ifdef TTY_DEBUG_HANGUP | |
1513 | char buf[64]; | |
1514 | ||
1515 | printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); | |
1516 | #endif | |
65f27f38 | 1517 | do_tty_hangup(&tty->hangup_work); |
1da177e4 | 1518 | } |
37bdfb07 | 1519 | |
1da177e4 LT |
1520 | EXPORT_SYMBOL(tty_vhangup); |
1521 | ||
af9b897e AC |
1522 | /** |
1523 | * tty_hung_up_p - was tty hung up | |
1524 | * @filp: file pointer of tty | |
1525 | * | |
1526 | * Return true if the tty has been subject to a vhangup or a carrier | |
1527 | * loss | |
1528 | */ | |
1529 | ||
37bdfb07 | 1530 | int tty_hung_up_p(struct file *filp) |
1da177e4 LT |
1531 | { |
1532 | return (filp->f_op == &hung_up_tty_fops); | |
1533 | } | |
1534 | ||
1535 | EXPORT_SYMBOL(tty_hung_up_p); | |
1536 | ||
522ed776 | 1537 | /** |
37bdfb07 AC |
1538 | * is_tty - checker whether file is a TTY |
1539 | * @filp: file handle that may be a tty | |
1540 | * | |
1541 | * Check if the file handle is a tty handle. | |
522ed776 | 1542 | */ |
37bdfb07 | 1543 | |
522ed776 MT |
1544 | int is_tty(struct file *filp) |
1545 | { | |
1546 | return filp->f_op->read == tty_read | |
1547 | || filp->f_op->read == hung_up_tty_read; | |
1548 | } | |
1549 | ||
ab521dc0 | 1550 | static void session_clear_tty(struct pid *session) |
24ec839c PZ |
1551 | { |
1552 | struct task_struct *p; | |
ab521dc0 | 1553 | do_each_pid_task(session, PIDTYPE_SID, p) { |
24ec839c | 1554 | proc_clear_tty(p); |
ab521dc0 | 1555 | } while_each_pid_task(session, PIDTYPE_SID, p); |
24ec839c PZ |
1556 | } |
1557 | ||
af9b897e AC |
1558 | /** |
1559 | * disassociate_ctty - disconnect controlling tty | |
1560 | * @on_exit: true if exiting so need to "hang up" the session | |
1da177e4 | 1561 | * |
af9b897e AC |
1562 | * This function is typically called only by the session leader, when |
1563 | * it wants to disassociate itself from its controlling tty. | |
1564 | * | |
1565 | * It performs the following functions: | |
1da177e4 LT |
1566 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
1567 | * (2) Clears the tty from being controlling the session | |
1568 | * (3) Clears the controlling tty for all processes in the | |
1569 | * session group. | |
1570 | * | |
af9b897e AC |
1571 | * The argument on_exit is set to 1 if called when a process is |
1572 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. | |
1573 | * | |
24ec839c | 1574 | * Locking: |
af9b897e | 1575 | * BKL is taken for hysterical raisins |
24ec839c PZ |
1576 | * tty_mutex is taken to protect tty |
1577 | * ->siglock is taken to protect ->signal/->sighand | |
1578 | * tasklist_lock is taken to walk process list for sessions | |
1579 | * ->siglock is taken to protect ->signal/->sighand | |
1da177e4 | 1580 | */ |
af9b897e | 1581 | |
1da177e4 LT |
1582 | void disassociate_ctty(int on_exit) |
1583 | { | |
1584 | struct tty_struct *tty; | |
ab521dc0 | 1585 | struct pid *tty_pgrp = NULL; |
1da177e4 LT |
1586 | |
1587 | lock_kernel(); | |
1588 | ||
70522e12 | 1589 | mutex_lock(&tty_mutex); |
24ec839c | 1590 | tty = get_current_tty(); |
1da177e4 | 1591 | if (tty) { |
ab521dc0 | 1592 | tty_pgrp = get_pid(tty->pgrp); |
70522e12 | 1593 | mutex_unlock(&tty_mutex); |
24ec839c | 1594 | /* XXX: here we race, there is nothing protecting tty */ |
1da177e4 LT |
1595 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
1596 | tty_vhangup(tty); | |
680a9671 | 1597 | } else if (on_exit) { |
ab521dc0 | 1598 | struct pid *old_pgrp; |
680a9671 EB |
1599 | spin_lock_irq(¤t->sighand->siglock); |
1600 | old_pgrp = current->signal->tty_old_pgrp; | |
ab521dc0 | 1601 | current->signal->tty_old_pgrp = NULL; |
680a9671 | 1602 | spin_unlock_irq(¤t->sighand->siglock); |
24ec839c | 1603 | if (old_pgrp) { |
ab521dc0 EB |
1604 | kill_pgrp(old_pgrp, SIGHUP, on_exit); |
1605 | kill_pgrp(old_pgrp, SIGCONT, on_exit); | |
1606 | put_pid(old_pgrp); | |
1da177e4 | 1607 | } |
70522e12 | 1608 | mutex_unlock(&tty_mutex); |
37bdfb07 | 1609 | unlock_kernel(); |
1da177e4 LT |
1610 | return; |
1611 | } | |
ab521dc0 EB |
1612 | if (tty_pgrp) { |
1613 | kill_pgrp(tty_pgrp, SIGHUP, on_exit); | |
1da177e4 | 1614 | if (!on_exit) |
ab521dc0 EB |
1615 | kill_pgrp(tty_pgrp, SIGCONT, on_exit); |
1616 | put_pid(tty_pgrp); | |
1da177e4 LT |
1617 | } |
1618 | ||
24ec839c | 1619 | spin_lock_irq(¤t->sighand->siglock); |
2a65f1d9 | 1620 | put_pid(current->signal->tty_old_pgrp); |
23cac8de | 1621 | current->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
1622 | spin_unlock_irq(¤t->sighand->siglock); |
1623 | ||
1624 | mutex_lock(&tty_mutex); | |
1625 | /* It is possible that do_tty_hangup has free'd this tty */ | |
1626 | tty = get_current_tty(); | |
1627 | if (tty) { | |
ab521dc0 EB |
1628 | put_pid(tty->session); |
1629 | put_pid(tty->pgrp); | |
1630 | tty->session = NULL; | |
1631 | tty->pgrp = NULL; | |
24ec839c PZ |
1632 | } else { |
1633 | #ifdef TTY_DEBUG_HANGUP | |
1634 | printk(KERN_DEBUG "error attempted to write to tty [0x%p]" | |
1635 | " = NULL", tty); | |
1636 | #endif | |
1637 | } | |
1638 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
1639 | |
1640 | /* Now clear signal->tty under the lock */ | |
1641 | read_lock(&tasklist_lock); | |
ab521dc0 | 1642 | session_clear_tty(task_session(current)); |
1da177e4 | 1643 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1644 | unlock_kernel(); |
1645 | } | |
1646 | ||
98a27ba4 EB |
1647 | /** |
1648 | * | |
1649 | * no_tty - Ensure the current process does not have a controlling tty | |
1650 | */ | |
1651 | void no_tty(void) | |
1652 | { | |
1653 | struct task_struct *tsk = current; | |
1654 | if (tsk->signal->leader) | |
1655 | disassociate_ctty(0); | |
1656 | proc_clear_tty(tsk); | |
1657 | } | |
1658 | ||
af9b897e AC |
1659 | |
1660 | /** | |
beb7dd86 | 1661 | * stop_tty - propagate flow control |
af9b897e AC |
1662 | * @tty: tty to stop |
1663 | * | |
1664 | * Perform flow control to the driver. For PTY/TTY pairs we | |
beb7dd86 | 1665 | * must also propagate the TIOCKPKT status. May be called |
af9b897e AC |
1666 | * on an already stopped device and will not re-call the driver |
1667 | * method. | |
1668 | * | |
1669 | * This functionality is used by both the line disciplines for | |
1670 | * halting incoming flow and by the driver. It may therefore be | |
1671 | * called from any context, may be under the tty atomic_write_lock | |
1672 | * but not always. | |
1673 | * | |
1674 | * Locking: | |
1675 | * Broken. Relies on BKL which is unsafe here. | |
1676 | */ | |
1677 | ||
1da177e4 LT |
1678 | void stop_tty(struct tty_struct *tty) |
1679 | { | |
1680 | if (tty->stopped) | |
1681 | return; | |
1682 | tty->stopped = 1; | |
1683 | if (tty->link && tty->link->packet) { | |
1684 | tty->ctrl_status &= ~TIOCPKT_START; | |
1685 | tty->ctrl_status |= TIOCPKT_STOP; | |
1686 | wake_up_interruptible(&tty->link->read_wait); | |
1687 | } | |
1688 | if (tty->driver->stop) | |
1689 | (tty->driver->stop)(tty); | |
1690 | } | |
1691 | ||
1692 | EXPORT_SYMBOL(stop_tty); | |
1693 | ||
af9b897e | 1694 | /** |
beb7dd86 | 1695 | * start_tty - propagate flow control |
af9b897e AC |
1696 | * @tty: tty to start |
1697 | * | |
1698 | * Start a tty that has been stopped if at all possible. Perform | |
3a4fa0a2 | 1699 | * any necessary wakeups and propagate the TIOCPKT status. If this |
af9b897e AC |
1700 | * is the tty was previous stopped and is being started then the |
1701 | * driver start method is invoked and the line discipline woken. | |
1702 | * | |
1703 | * Locking: | |
1704 | * Broken. Relies on BKL which is unsafe here. | |
1705 | */ | |
1706 | ||
1da177e4 LT |
1707 | void start_tty(struct tty_struct *tty) |
1708 | { | |
1709 | if (!tty->stopped || tty->flow_stopped) | |
1710 | return; | |
1711 | tty->stopped = 0; | |
1712 | if (tty->link && tty->link->packet) { | |
1713 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
1714 | tty->ctrl_status |= TIOCPKT_START; | |
1715 | wake_up_interruptible(&tty->link->read_wait); | |
1716 | } | |
1717 | if (tty->driver->start) | |
1718 | (tty->driver->start)(tty); | |
1da177e4 LT |
1719 | /* If we have a running line discipline it may need kicking */ |
1720 | tty_wakeup(tty); | |
1da177e4 LT |
1721 | } |
1722 | ||
1723 | EXPORT_SYMBOL(start_tty); | |
1724 | ||
af9b897e AC |
1725 | /** |
1726 | * tty_read - read method for tty device files | |
1727 | * @file: pointer to tty file | |
1728 | * @buf: user buffer | |
1729 | * @count: size of user buffer | |
1730 | * @ppos: unused | |
1731 | * | |
1732 | * Perform the read system call function on this terminal device. Checks | |
1733 | * for hung up devices before calling the line discipline method. | |
1734 | * | |
1735 | * Locking: | |
1736 | * Locks the line discipline internally while needed | |
1737 | * For historical reasons the line discipline read method is | |
1738 | * invoked under the BKL. This will go away in time so do not rely on it | |
1739 | * in new code. Multiple read calls may be outstanding in parallel. | |
1740 | */ | |
1741 | ||
37bdfb07 | 1742 | static ssize_t tty_read(struct file *file, char __user *buf, size_t count, |
1da177e4 LT |
1743 | loff_t *ppos) |
1744 | { | |
1745 | int i; | |
37bdfb07 | 1746 | struct tty_struct *tty; |
1da177e4 LT |
1747 | struct inode *inode; |
1748 | struct tty_ldisc *ld; | |
1749 | ||
1750 | tty = (struct tty_struct *)file->private_data; | |
a7113a96 | 1751 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1752 | if (tty_paranoia_check(tty, inode, "tty_read")) |
1753 | return -EIO; | |
1754 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1755 | return -EIO; | |
1756 | ||
1757 | /* We want to wait for the line discipline to sort out in this | |
1758 | situation */ | |
1759 | ld = tty_ldisc_ref_wait(tty); | |
1760 | lock_kernel(); | |
1761 | if (ld->read) | |
37bdfb07 | 1762 | i = (ld->read)(tty, file, buf, count); |
1da177e4 LT |
1763 | else |
1764 | i = -EIO; | |
1765 | tty_ldisc_deref(ld); | |
1766 | unlock_kernel(); | |
1767 | if (i > 0) | |
1768 | inode->i_atime = current_fs_time(inode->i_sb); | |
1769 | return i; | |
1770 | } | |
1771 | ||
9c1729db AC |
1772 | void tty_write_unlock(struct tty_struct *tty) |
1773 | { | |
1774 | mutex_unlock(&tty->atomic_write_lock); | |
1775 | wake_up_interruptible(&tty->write_wait); | |
1776 | } | |
1777 | ||
1778 | int tty_write_lock(struct tty_struct *tty, int ndelay) | |
1779 | { | |
1780 | if (!mutex_trylock(&tty->atomic_write_lock)) { | |
1781 | if (ndelay) | |
1782 | return -EAGAIN; | |
1783 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) | |
1784 | return -ERESTARTSYS; | |
1785 | } | |
1786 | return 0; | |
1787 | } | |
1788 | ||
1da177e4 LT |
1789 | /* |
1790 | * Split writes up in sane blocksizes to avoid | |
1791 | * denial-of-service type attacks | |
1792 | */ | |
1793 | static inline ssize_t do_tty_write( | |
1794 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
1795 | struct tty_struct *tty, | |
1796 | struct file *file, | |
1797 | const char __user *buf, | |
1798 | size_t count) | |
1799 | { | |
9c1729db | 1800 | ssize_t ret, written = 0; |
1da177e4 | 1801 | unsigned int chunk; |
37bdfb07 | 1802 | |
9c1729db AC |
1803 | ret = tty_write_lock(tty, file->f_flags & O_NDELAY); |
1804 | if (ret < 0) | |
1805 | return ret; | |
1da177e4 LT |
1806 | |
1807 | /* | |
1808 | * We chunk up writes into a temporary buffer. This | |
1809 | * simplifies low-level drivers immensely, since they | |
1810 | * don't have locking issues and user mode accesses. | |
1811 | * | |
1812 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
1813 | * big chunk-size.. | |
1814 | * | |
1815 | * The default chunk-size is 2kB, because the NTTY | |
1816 | * layer has problems with bigger chunks. It will | |
1817 | * claim to be able to handle more characters than | |
1818 | * it actually does. | |
af9b897e AC |
1819 | * |
1820 | * FIXME: This can probably go away now except that 64K chunks | |
1821 | * are too likely to fail unless switched to vmalloc... | |
1da177e4 LT |
1822 | */ |
1823 | chunk = 2048; | |
1824 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
1825 | chunk = 65536; | |
1826 | if (count < chunk) | |
1827 | chunk = count; | |
1828 | ||
70522e12 | 1829 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
1da177e4 LT |
1830 | if (tty->write_cnt < chunk) { |
1831 | unsigned char *buf; | |
1832 | ||
1833 | if (chunk < 1024) | |
1834 | chunk = 1024; | |
1835 | ||
1836 | buf = kmalloc(chunk, GFP_KERNEL); | |
1837 | if (!buf) { | |
9c1729db AC |
1838 | ret = -ENOMEM; |
1839 | goto out; | |
1da177e4 LT |
1840 | } |
1841 | kfree(tty->write_buf); | |
1842 | tty->write_cnt = chunk; | |
1843 | tty->write_buf = buf; | |
1844 | } | |
1845 | ||
1846 | /* Do the write .. */ | |
1847 | for (;;) { | |
1848 | size_t size = count; | |
1849 | if (size > chunk) | |
1850 | size = chunk; | |
1851 | ret = -EFAULT; | |
1852 | if (copy_from_user(tty->write_buf, buf, size)) | |
1853 | break; | |
1854 | lock_kernel(); | |
1855 | ret = write(tty, file, tty->write_buf, size); | |
1856 | unlock_kernel(); | |
1857 | if (ret <= 0) | |
1858 | break; | |
1859 | written += ret; | |
1860 | buf += ret; | |
1861 | count -= ret; | |
1862 | if (!count) | |
1863 | break; | |
1864 | ret = -ERESTARTSYS; | |
1865 | if (signal_pending(current)) | |
1866 | break; | |
1867 | cond_resched(); | |
1868 | } | |
1869 | if (written) { | |
a7113a96 | 1870 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1871 | inode->i_mtime = current_fs_time(inode->i_sb); |
1872 | ret = written; | |
1873 | } | |
9c1729db AC |
1874 | out: |
1875 | tty_write_unlock(tty); | |
1da177e4 LT |
1876 | return ret; |
1877 | } | |
1878 | ||
1879 | ||
af9b897e AC |
1880 | /** |
1881 | * tty_write - write method for tty device file | |
1882 | * @file: tty file pointer | |
1883 | * @buf: user data to write | |
1884 | * @count: bytes to write | |
1885 | * @ppos: unused | |
1886 | * | |
1887 | * Write data to a tty device via the line discipline. | |
1888 | * | |
1889 | * Locking: | |
1890 | * Locks the line discipline as required | |
1891 | * Writes to the tty driver are serialized by the atomic_write_lock | |
1892 | * and are then processed in chunks to the device. The line discipline | |
1893 | * write method will not be involked in parallel for each device | |
1894 | * The line discipline write method is called under the big | |
1895 | * kernel lock for historical reasons. New code should not rely on this. | |
1896 | */ | |
1897 | ||
37bdfb07 AC |
1898 | static ssize_t tty_write(struct file *file, const char __user *buf, |
1899 | size_t count, loff_t *ppos) | |
1da177e4 | 1900 | { |
37bdfb07 | 1901 | struct tty_struct *tty; |
a7113a96 | 1902 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1903 | ssize_t ret; |
1904 | struct tty_ldisc *ld; | |
37bdfb07 | 1905 | |
1da177e4 LT |
1906 | tty = (struct tty_struct *)file->private_data; |
1907 | if (tty_paranoia_check(tty, inode, "tty_write")) | |
1908 | return -EIO; | |
37bdfb07 AC |
1909 | if (!tty || !tty->driver->write || |
1910 | (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1911 | return -EIO; | |
1da177e4 | 1912 | |
37bdfb07 | 1913 | ld = tty_ldisc_ref_wait(tty); |
1da177e4 LT |
1914 | if (!ld->write) |
1915 | ret = -EIO; | |
1916 | else | |
1917 | ret = do_tty_write(ld->write, tty, file, buf, count); | |
1918 | tty_ldisc_deref(ld); | |
1919 | return ret; | |
1920 | } | |
1921 | ||
37bdfb07 AC |
1922 | ssize_t redirected_tty_write(struct file *file, const char __user *buf, |
1923 | size_t count, loff_t *ppos) | |
1da177e4 LT |
1924 | { |
1925 | struct file *p = NULL; | |
1926 | ||
1927 | spin_lock(&redirect_lock); | |
1928 | if (redirect) { | |
1929 | get_file(redirect); | |
1930 | p = redirect; | |
1931 | } | |
1932 | spin_unlock(&redirect_lock); | |
1933 | ||
1934 | if (p) { | |
1935 | ssize_t res; | |
1936 | res = vfs_write(p, buf, count, &p->f_pos); | |
1937 | fput(p); | |
1938 | return res; | |
1939 | } | |
1da177e4 LT |
1940 | return tty_write(file, buf, count, ppos); |
1941 | } | |
1942 | ||
1943 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
1944 | ||
af9b897e AC |
1945 | /** |
1946 | * pty_line_name - generate name for a pty | |
1947 | * @driver: the tty driver in use | |
1948 | * @index: the minor number | |
1949 | * @p: output buffer of at least 6 bytes | |
1950 | * | |
1951 | * Generate a name from a driver reference and write it to the output | |
1952 | * buffer. | |
1953 | * | |
1954 | * Locking: None | |
1955 | */ | |
1956 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1957 | { |
1958 | int i = index + driver->name_base; | |
1959 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
1960 | sprintf(p, "%s%c%x", | |
37bdfb07 AC |
1961 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, |
1962 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1da177e4 LT |
1963 | } |
1964 | ||
af9b897e AC |
1965 | /** |
1966 | * pty_line_name - generate name for a tty | |
1967 | * @driver: the tty driver in use | |
1968 | * @index: the minor number | |
1969 | * @p: output buffer of at least 7 bytes | |
1970 | * | |
1971 | * Generate a name from a driver reference and write it to the output | |
1972 | * buffer. | |
1973 | * | |
1974 | * Locking: None | |
1975 | */ | |
1976 | static void tty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1977 | { |
1978 | sprintf(p, "%s%d", driver->name, index + driver->name_base); | |
1979 | } | |
1980 | ||
af9b897e AC |
1981 | /** |
1982 | * init_dev - initialise a tty device | |
1983 | * @driver: tty driver we are opening a device on | |
1984 | * @idx: device index | |
1985 | * @tty: returned tty structure | |
1986 | * | |
1987 | * Prepare a tty device. This may not be a "new" clean device but | |
1988 | * could also be an active device. The pty drivers require special | |
1989 | * handling because of this. | |
1990 | * | |
1991 | * Locking: | |
1992 | * The function is called under the tty_mutex, which | |
1993 | * protects us from the tty struct or driver itself going away. | |
1994 | * | |
1995 | * On exit the tty device has the line discipline attached and | |
1996 | * a reference count of 1. If a pair was created for pty/tty use | |
1997 | * and the other was a pty master then it too has a reference count of 1. | |
1998 | * | |
1da177e4 | 1999 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
70522e12 IM |
2000 | * failed open. The new code protects the open with a mutex, so it's |
2001 | * really quite straightforward. The mutex locking can probably be | |
1da177e4 LT |
2002 | * relaxed for the (most common) case of reopening a tty. |
2003 | */ | |
af9b897e | 2004 | |
1da177e4 LT |
2005 | static int init_dev(struct tty_driver *driver, int idx, |
2006 | struct tty_struct **ret_tty) | |
2007 | { | |
2008 | struct tty_struct *tty, *o_tty; | |
edc6afc5 AC |
2009 | struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; |
2010 | struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; | |
af9b897e | 2011 | int retval = 0; |
1da177e4 LT |
2012 | |
2013 | /* check whether we're reopening an existing tty */ | |
2014 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2015 | tty = devpts_get_tty(idx); | |
5a39e8c6 ASRF |
2016 | /* |
2017 | * If we don't have a tty here on a slave open, it's because | |
2018 | * the master already started the close process and there's | |
2019 | * no relation between devpts file and tty anymore. | |
2020 | */ | |
2021 | if (!tty && driver->subtype == PTY_TYPE_SLAVE) { | |
2022 | retval = -EIO; | |
2023 | goto end_init; | |
2024 | } | |
2025 | /* | |
2026 | * It's safe from now on because init_dev() is called with | |
2027 | * tty_mutex held and release_dev() won't change tty->count | |
2028 | * or tty->flags without having to grab tty_mutex | |
2029 | */ | |
1da177e4 LT |
2030 | if (tty && driver->subtype == PTY_TYPE_MASTER) |
2031 | tty = tty->link; | |
2032 | } else { | |
2033 | tty = driver->ttys[idx]; | |
2034 | } | |
2035 | if (tty) goto fast_track; | |
2036 | ||
2037 | /* | |
2038 | * First time open is complex, especially for PTY devices. | |
2039 | * This code guarantees that either everything succeeds and the | |
2040 | * TTY is ready for operation, or else the table slots are vacated | |
37bdfb07 | 2041 | * and the allocated memory released. (Except that the termios |
1da177e4 LT |
2042 | * and locked termios may be retained.) |
2043 | */ | |
2044 | ||
2045 | if (!try_module_get(driver->owner)) { | |
2046 | retval = -ENODEV; | |
2047 | goto end_init; | |
2048 | } | |
2049 | ||
2050 | o_tty = NULL; | |
2051 | tp = o_tp = NULL; | |
2052 | ltp = o_ltp = NULL; | |
2053 | ||
2054 | tty = alloc_tty_struct(); | |
37bdfb07 | 2055 | if (!tty) |
1da177e4 LT |
2056 | goto fail_no_mem; |
2057 | initialize_tty_struct(tty); | |
2058 | tty->driver = driver; | |
2059 | tty->index = idx; | |
2060 | tty_line_name(driver, idx, tty->name); | |
2061 | ||
2062 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2063 | tp_loc = &tty->termios; | |
2064 | ltp_loc = &tty->termios_locked; | |
2065 | } else { | |
2066 | tp_loc = &driver->termios[idx]; | |
2067 | ltp_loc = &driver->termios_locked[idx]; | |
2068 | } | |
2069 | ||
2070 | if (!*tp_loc) { | |
abcb1ff3 | 2071 | tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2072 | if (!tp) |
2073 | goto free_mem_out; | |
2074 | *tp = driver->init_termios; | |
2075 | } | |
2076 | ||
2077 | if (!*ltp_loc) { | |
506eb99a | 2078 | ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2079 | if (!ltp) |
2080 | goto free_mem_out; | |
1da177e4 LT |
2081 | } |
2082 | ||
2083 | if (driver->type == TTY_DRIVER_TYPE_PTY) { | |
2084 | o_tty = alloc_tty_struct(); | |
2085 | if (!o_tty) | |
2086 | goto free_mem_out; | |
2087 | initialize_tty_struct(o_tty); | |
2088 | o_tty->driver = driver->other; | |
2089 | o_tty->index = idx; | |
2090 | tty_line_name(driver->other, idx, o_tty->name); | |
2091 | ||
2092 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2093 | o_tp_loc = &o_tty->termios; | |
2094 | o_ltp_loc = &o_tty->termios_locked; | |
2095 | } else { | |
2096 | o_tp_loc = &driver->other->termios[idx]; | |
2097 | o_ltp_loc = &driver->other->termios_locked[idx]; | |
2098 | } | |
2099 | ||
2100 | if (!*o_tp_loc) { | |
abcb1ff3 | 2101 | o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2102 | if (!o_tp) |
2103 | goto free_mem_out; | |
2104 | *o_tp = driver->other->init_termios; | |
2105 | } | |
2106 | ||
2107 | if (!*o_ltp_loc) { | |
506eb99a | 2108 | o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2109 | if (!o_ltp) |
2110 | goto free_mem_out; | |
1da177e4 LT |
2111 | } |
2112 | ||
2113 | /* | |
2114 | * Everything allocated ... set up the o_tty structure. | |
2115 | */ | |
37bdfb07 | 2116 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) |
1da177e4 | 2117 | driver->other->ttys[idx] = o_tty; |
1da177e4 LT |
2118 | if (!*o_tp_loc) |
2119 | *o_tp_loc = o_tp; | |
2120 | if (!*o_ltp_loc) | |
2121 | *o_ltp_loc = o_ltp; | |
2122 | o_tty->termios = *o_tp_loc; | |
2123 | o_tty->termios_locked = *o_ltp_loc; | |
2124 | driver->other->refcount++; | |
2125 | if (driver->subtype == PTY_TYPE_MASTER) | |
2126 | o_tty->count++; | |
2127 | ||
2128 | /* Establish the links in both directions */ | |
2129 | tty->link = o_tty; | |
2130 | o_tty->link = tty; | |
2131 | } | |
2132 | ||
37bdfb07 | 2133 | /* |
1da177e4 | 2134 | * All structures have been allocated, so now we install them. |
d5698c28 | 2135 | * Failures after this point use release_tty to clean up, so |
1da177e4 LT |
2136 | * there's no need to null out the local pointers. |
2137 | */ | |
37bdfb07 | 2138 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) |
1da177e4 | 2139 | driver->ttys[idx] = tty; |
37bdfb07 | 2140 | |
1da177e4 LT |
2141 | if (!*tp_loc) |
2142 | *tp_loc = tp; | |
2143 | if (!*ltp_loc) | |
2144 | *ltp_loc = ltp; | |
2145 | tty->termios = *tp_loc; | |
2146 | tty->termios_locked = *ltp_loc; | |
edc6afc5 AC |
2147 | /* Compatibility until drivers always set this */ |
2148 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
2149 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1da177e4 LT |
2150 | driver->refcount++; |
2151 | tty->count++; | |
2152 | ||
37bdfb07 | 2153 | /* |
1da177e4 | 2154 | * Structures all installed ... call the ldisc open routines. |
d5698c28 CH |
2155 | * If we fail here just call release_tty to clean up. No need |
2156 | * to decrement the use counts, as release_tty doesn't care. | |
1da177e4 LT |
2157 | */ |
2158 | ||
2159 | if (tty->ldisc.open) { | |
2160 | retval = (tty->ldisc.open)(tty); | |
2161 | if (retval) | |
2162 | goto release_mem_out; | |
2163 | } | |
2164 | if (o_tty && o_tty->ldisc.open) { | |
2165 | retval = (o_tty->ldisc.open)(o_tty); | |
2166 | if (retval) { | |
2167 | if (tty->ldisc.close) | |
2168 | (tty->ldisc.close)(tty); | |
2169 | goto release_mem_out; | |
2170 | } | |
2171 | tty_ldisc_enable(o_tty); | |
2172 | } | |
2173 | tty_ldisc_enable(tty); | |
2174 | goto success; | |
2175 | ||
2176 | /* | |
2177 | * This fast open can be used if the tty is already open. | |
2178 | * No memory is allocated, and the only failures are from | |
2179 | * attempting to open a closing tty or attempting multiple | |
2180 | * opens on a pty master. | |
2181 | */ | |
2182 | fast_track: | |
2183 | if (test_bit(TTY_CLOSING, &tty->flags)) { | |
2184 | retval = -EIO; | |
2185 | goto end_init; | |
2186 | } | |
2187 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
2188 | driver->subtype == PTY_TYPE_MASTER) { | |
2189 | /* | |
37bdfb07 | 2190 | * special case for PTY masters: only one open permitted, |
1da177e4 LT |
2191 | * and the slave side open count is incremented as well. |
2192 | */ | |
2193 | if (tty->count) { | |
2194 | retval = -EIO; | |
2195 | goto end_init; | |
2196 | } | |
2197 | tty->link->count++; | |
2198 | } | |
2199 | tty->count++; | |
2200 | tty->driver = driver; /* N.B. why do this every time?? */ | |
2201 | ||
2202 | /* FIXME */ | |
37bdfb07 | 2203 | if (!test_bit(TTY_LDISC, &tty->flags)) |
1da177e4 LT |
2204 | printk(KERN_ERR "init_dev but no ldisc\n"); |
2205 | success: | |
2206 | *ret_tty = tty; | |
37bdfb07 | 2207 | |
70522e12 | 2208 | /* All paths come through here to release the mutex */ |
1da177e4 LT |
2209 | end_init: |
2210 | return retval; | |
2211 | ||
2212 | /* Release locally allocated memory ... nothing placed in slots */ | |
2213 | free_mem_out: | |
735d5661 | 2214 | kfree(o_tp); |
1da177e4 LT |
2215 | if (o_tty) |
2216 | free_tty_struct(o_tty); | |
735d5661 JJ |
2217 | kfree(ltp); |
2218 | kfree(tp); | |
1da177e4 LT |
2219 | free_tty_struct(tty); |
2220 | ||
2221 | fail_no_mem: | |
2222 | module_put(driver->owner); | |
2223 | retval = -ENOMEM; | |
2224 | goto end_init; | |
2225 | ||
d5698c28 | 2226 | /* call the tty release_tty routine to clean out this slot */ |
1da177e4 | 2227 | release_mem_out: |
4050914f AM |
2228 | if (printk_ratelimit()) |
2229 | printk(KERN_INFO "init_dev: ldisc open failed, " | |
2230 | "clearing slot %d\n", idx); | |
d5698c28 | 2231 | release_tty(tty, idx); |
1da177e4 LT |
2232 | goto end_init; |
2233 | } | |
2234 | ||
af9b897e | 2235 | /** |
d5698c28 | 2236 | * release_one_tty - release tty structure memory |
af9b897e AC |
2237 | * |
2238 | * Releases memory associated with a tty structure, and clears out the | |
2239 | * driver table slots. This function is called when a device is no longer | |
2240 | * in use. It also gets called when setup of a device fails. | |
2241 | * | |
2242 | * Locking: | |
2243 | * tty_mutex - sometimes only | |
2244 | * takes the file list lock internally when working on the list | |
2245 | * of ttys that the driver keeps. | |
2246 | * FIXME: should we require tty_mutex is held here ?? | |
1da177e4 | 2247 | */ |
d5698c28 | 2248 | static void release_one_tty(struct tty_struct *tty, int idx) |
1da177e4 | 2249 | { |
1da177e4 | 2250 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
d5698c28 | 2251 | struct ktermios *tp; |
1da177e4 LT |
2252 | |
2253 | if (!devpts) | |
2254 | tty->driver->ttys[idx] = NULL; | |
d5698c28 | 2255 | |
1da177e4 LT |
2256 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
2257 | tp = tty->termios; | |
2258 | if (!devpts) | |
2259 | tty->driver->termios[idx] = NULL; | |
2260 | kfree(tp); | |
2261 | ||
2262 | tp = tty->termios_locked; | |
2263 | if (!devpts) | |
2264 | tty->driver->termios_locked[idx] = NULL; | |
2265 | kfree(tp); | |
2266 | } | |
2267 | ||
d5698c28 | 2268 | |
1da177e4 LT |
2269 | tty->magic = 0; |
2270 | tty->driver->refcount--; | |
d5698c28 | 2271 | |
1da177e4 LT |
2272 | file_list_lock(); |
2273 | list_del_init(&tty->tty_files); | |
2274 | file_list_unlock(); | |
d5698c28 | 2275 | |
1da177e4 LT |
2276 | free_tty_struct(tty); |
2277 | } | |
2278 | ||
d5698c28 CH |
2279 | /** |
2280 | * release_tty - release tty structure memory | |
2281 | * | |
2282 | * Release both @tty and a possible linked partner (think pty pair), | |
2283 | * and decrement the refcount of the backing module. | |
2284 | * | |
2285 | * Locking: | |
2286 | * tty_mutex - sometimes only | |
2287 | * takes the file list lock internally when working on the list | |
2288 | * of ttys that the driver keeps. | |
2289 | * FIXME: should we require tty_mutex is held here ?? | |
2290 | */ | |
2291 | static void release_tty(struct tty_struct *tty, int idx) | |
2292 | { | |
2293 | struct tty_driver *driver = tty->driver; | |
2294 | ||
2295 | if (tty->link) | |
2296 | release_one_tty(tty->link, idx); | |
2297 | release_one_tty(tty, idx); | |
2298 | module_put(driver->owner); | |
2299 | } | |
2300 | ||
1da177e4 LT |
2301 | /* |
2302 | * Even releasing the tty structures is a tricky business.. We have | |
2303 | * to be very careful that the structures are all released at the | |
2304 | * same time, as interrupts might otherwise get the wrong pointers. | |
2305 | * | |
2306 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
2307 | * lead to double frees or releasing memory still in use. | |
2308 | */ | |
37bdfb07 | 2309 | static void release_dev(struct file *filp) |
1da177e4 LT |
2310 | { |
2311 | struct tty_struct *tty, *o_tty; | |
2312 | int pty_master, tty_closing, o_tty_closing, do_sleep; | |
14a6283e | 2313 | int devpts; |
1da177e4 LT |
2314 | int idx; |
2315 | char buf[64]; | |
2316 | unsigned long flags; | |
37bdfb07 | 2317 | |
1da177e4 | 2318 | tty = (struct tty_struct *)filp->private_data; |
37bdfb07 AC |
2319 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, |
2320 | "release_dev")) | |
1da177e4 LT |
2321 | return; |
2322 | ||
2323 | check_tty_count(tty, "release_dev"); | |
2324 | ||
2325 | tty_fasync(-1, filp, 0); | |
2326 | ||
2327 | idx = tty->index; | |
2328 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2329 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2330 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; | |
1da177e4 LT |
2331 | o_tty = tty->link; |
2332 | ||
2333 | #ifdef TTY_PARANOIA_CHECK | |
2334 | if (idx < 0 || idx >= tty->driver->num) { | |
2335 | printk(KERN_DEBUG "release_dev: bad idx when trying to " | |
2336 | "free (%s)\n", tty->name); | |
2337 | return; | |
2338 | } | |
2339 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2340 | if (tty != tty->driver->ttys[idx]) { | |
2341 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " | |
2342 | "for (%s)\n", idx, tty->name); | |
2343 | return; | |
2344 | } | |
2345 | if (tty->termios != tty->driver->termios[idx]) { | |
2346 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " | |
2347 | "for (%s)\n", | |
2348 | idx, tty->name); | |
2349 | return; | |
2350 | } | |
2351 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { | |
2352 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " | |
2353 | "termios_locked for (%s)\n", | |
2354 | idx, tty->name); | |
2355 | return; | |
2356 | } | |
2357 | } | |
2358 | #endif | |
2359 | ||
2360 | #ifdef TTY_DEBUG_HANGUP | |
2361 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", | |
2362 | tty_name(tty, buf), tty->count); | |
2363 | #endif | |
2364 | ||
2365 | #ifdef TTY_PARANOIA_CHECK | |
2366 | if (tty->driver->other && | |
2367 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2368 | if (o_tty != tty->driver->other->ttys[idx]) { | |
2369 | printk(KERN_DEBUG "release_dev: other->table[%d] " | |
2370 | "not o_tty for (%s)\n", | |
2371 | idx, tty->name); | |
2372 | return; | |
2373 | } | |
2374 | if (o_tty->termios != tty->driver->other->termios[idx]) { | |
2375 | printk(KERN_DEBUG "release_dev: other->termios[%d] " | |
2376 | "not o_termios for (%s)\n", | |
2377 | idx, tty->name); | |
2378 | return; | |
2379 | } | |
37bdfb07 | 2380 | if (o_tty->termios_locked != |
1da177e4 LT |
2381 | tty->driver->other->termios_locked[idx]) { |
2382 | printk(KERN_DEBUG "release_dev: other->termios_locked[" | |
2383 | "%d] not o_termios_locked for (%s)\n", | |
2384 | idx, tty->name); | |
2385 | return; | |
2386 | } | |
2387 | if (o_tty->link != tty) { | |
2388 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); | |
2389 | return; | |
2390 | } | |
2391 | } | |
2392 | #endif | |
2393 | if (tty->driver->close) | |
2394 | tty->driver->close(tty, filp); | |
2395 | ||
2396 | /* | |
2397 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
2398 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
2399 | * wait queues and kick everyone out _before_ actually starting to | |
2400 | * close. This ensures that we won't block while releasing the tty | |
2401 | * structure. | |
2402 | * | |
2403 | * The test for the o_tty closing is necessary, since the master and | |
2404 | * slave sides may close in any order. If the slave side closes out | |
2405 | * first, its count will be one, since the master side holds an open. | |
2406 | * Thus this test wouldn't be triggered at the time the slave closes, | |
2407 | * so we do it now. | |
2408 | * | |
2409 | * Note that it's possible for the tty to be opened again while we're | |
2410 | * flushing out waiters. By recalculating the closing flags before | |
2411 | * each iteration we avoid any problems. | |
2412 | */ | |
2413 | while (1) { | |
2414 | /* Guard against races with tty->count changes elsewhere and | |
2415 | opens on /dev/tty */ | |
37bdfb07 | 2416 | |
70522e12 | 2417 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2418 | tty_closing = tty->count <= 1; |
2419 | o_tty_closing = o_tty && | |
2420 | (o_tty->count <= (pty_master ? 1 : 0)); | |
1da177e4 LT |
2421 | do_sleep = 0; |
2422 | ||
2423 | if (tty_closing) { | |
2424 | if (waitqueue_active(&tty->read_wait)) { | |
2425 | wake_up(&tty->read_wait); | |
2426 | do_sleep++; | |
2427 | } | |
2428 | if (waitqueue_active(&tty->write_wait)) { | |
2429 | wake_up(&tty->write_wait); | |
2430 | do_sleep++; | |
2431 | } | |
2432 | } | |
2433 | if (o_tty_closing) { | |
2434 | if (waitqueue_active(&o_tty->read_wait)) { | |
2435 | wake_up(&o_tty->read_wait); | |
2436 | do_sleep++; | |
2437 | } | |
2438 | if (waitqueue_active(&o_tty->write_wait)) { | |
2439 | wake_up(&o_tty->write_wait); | |
2440 | do_sleep++; | |
2441 | } | |
2442 | } | |
2443 | if (!do_sleep) | |
2444 | break; | |
2445 | ||
2446 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " | |
2447 | "active!\n", tty_name(tty, buf)); | |
70522e12 | 2448 | mutex_unlock(&tty_mutex); |
1da177e4 | 2449 | schedule(); |
37bdfb07 | 2450 | } |
1da177e4 LT |
2451 | |
2452 | /* | |
37bdfb07 AC |
2453 | * The closing flags are now consistent with the open counts on |
2454 | * both sides, and we've completed the last operation that could | |
1da177e4 LT |
2455 | * block, so it's safe to proceed with closing. |
2456 | */ | |
1da177e4 LT |
2457 | if (pty_master) { |
2458 | if (--o_tty->count < 0) { | |
2459 | printk(KERN_WARNING "release_dev: bad pty slave count " | |
2460 | "(%d) for %s\n", | |
2461 | o_tty->count, tty_name(o_tty, buf)); | |
2462 | o_tty->count = 0; | |
2463 | } | |
2464 | } | |
2465 | if (--tty->count < 0) { | |
2466 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", | |
2467 | tty->count, tty_name(tty, buf)); | |
2468 | tty->count = 0; | |
2469 | } | |
37bdfb07 | 2470 | |
1da177e4 LT |
2471 | /* |
2472 | * We've decremented tty->count, so we need to remove this file | |
2473 | * descriptor off the tty->tty_files list; this serves two | |
2474 | * purposes: | |
2475 | * - check_tty_count sees the correct number of file descriptors | |
2476 | * associated with this tty. | |
2477 | * - do_tty_hangup no longer sees this file descriptor as | |
2478 | * something that needs to be handled for hangups. | |
2479 | */ | |
2480 | file_kill(filp); | |
2481 | filp->private_data = NULL; | |
2482 | ||
2483 | /* | |
2484 | * Perform some housekeeping before deciding whether to return. | |
2485 | * | |
2486 | * Set the TTY_CLOSING flag if this was the last open. In the | |
2487 | * case of a pty we may have to wait around for the other side | |
2488 | * to close, and TTY_CLOSING makes sure we can't be reopened. | |
2489 | */ | |
37bdfb07 | 2490 | if (tty_closing) |
1da177e4 | 2491 | set_bit(TTY_CLOSING, &tty->flags); |
37bdfb07 | 2492 | if (o_tty_closing) |
1da177e4 LT |
2493 | set_bit(TTY_CLOSING, &o_tty->flags); |
2494 | ||
2495 | /* | |
2496 | * If _either_ side is closing, make sure there aren't any | |
2497 | * processes that still think tty or o_tty is their controlling | |
2498 | * tty. | |
2499 | */ | |
2500 | if (tty_closing || o_tty_closing) { | |
1da177e4 | 2501 | read_lock(&tasklist_lock); |
24ec839c | 2502 | session_clear_tty(tty->session); |
1da177e4 | 2503 | if (o_tty) |
24ec839c | 2504 | session_clear_tty(o_tty->session); |
1da177e4 LT |
2505 | read_unlock(&tasklist_lock); |
2506 | } | |
2507 | ||
70522e12 | 2508 | mutex_unlock(&tty_mutex); |
da965822 | 2509 | |
1da177e4 LT |
2510 | /* check whether both sides are closing ... */ |
2511 | if (!tty_closing || (o_tty && !o_tty_closing)) | |
2512 | return; | |
37bdfb07 | 2513 | |
1da177e4 LT |
2514 | #ifdef TTY_DEBUG_HANGUP |
2515 | printk(KERN_DEBUG "freeing tty structure..."); | |
2516 | #endif | |
2517 | /* | |
2518 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then | |
2519 | * kill any delayed work. As this is the final close it does not | |
2520 | * race with the set_ldisc code path. | |
2521 | */ | |
2522 | clear_bit(TTY_LDISC, &tty->flags); | |
33f0f88f | 2523 | cancel_delayed_work(&tty->buf.work); |
1da177e4 LT |
2524 | |
2525 | /* | |
33f0f88f | 2526 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 | 2527 | */ |
37bdfb07 | 2528 | |
1da177e4 | 2529 | flush_scheduled_work(); |
37bdfb07 | 2530 | |
1da177e4 LT |
2531 | /* |
2532 | * Wait for any short term users (we know they are just driver | |
2533 | * side waiters as the file is closing so user count on the file | |
2534 | * side is zero. | |
2535 | */ | |
2536 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
37bdfb07 | 2537 | while (tty->ldisc.refcount) { |
1da177e4 LT |
2538 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
2539 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); | |
2540 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2541 | } | |
2542 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2543 | /* | |
2544 | * Shutdown the current line discipline, and reset it to N_TTY. | |
2545 | * N.B. why reset ldisc when we're releasing the memory?? | |
2546 | * | |
2547 | * FIXME: this MUST get fixed for the new reflocking | |
2548 | */ | |
2549 | if (tty->ldisc.close) | |
2550 | (tty->ldisc.close)(tty); | |
2551 | tty_ldisc_put(tty->ldisc.num); | |
37bdfb07 | 2552 | |
1da177e4 LT |
2553 | /* |
2554 | * Switch the line discipline back | |
2555 | */ | |
2556 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
37bdfb07 | 2557 | tty_set_termios_ldisc(tty, N_TTY); |
1da177e4 LT |
2558 | if (o_tty) { |
2559 | /* FIXME: could o_tty be in setldisc here ? */ | |
2560 | clear_bit(TTY_LDISC, &o_tty->flags); | |
2561 | if (o_tty->ldisc.close) | |
2562 | (o_tty->ldisc.close)(o_tty); | |
2563 | tty_ldisc_put(o_tty->ldisc.num); | |
2564 | tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); | |
37bdfb07 | 2565 | tty_set_termios_ldisc(o_tty, N_TTY); |
1da177e4 LT |
2566 | } |
2567 | /* | |
d5698c28 | 2568 | * The release_tty function takes care of the details of clearing |
1da177e4 LT |
2569 | * the slots and preserving the termios structure. |
2570 | */ | |
d5698c28 | 2571 | release_tty(tty, idx); |
1da177e4 LT |
2572 | |
2573 | #ifdef CONFIG_UNIX98_PTYS | |
2574 | /* Make this pty number available for reallocation */ | |
2575 | if (devpts) { | |
a6752f3f | 2576 | mutex_lock(&allocated_ptys_lock); |
1da177e4 | 2577 | idr_remove(&allocated_ptys, idx); |
a6752f3f | 2578 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2579 | } |
2580 | #endif | |
2581 | ||
2582 | } | |
2583 | ||
af9b897e AC |
2584 | /** |
2585 | * tty_open - open a tty device | |
2586 | * @inode: inode of device file | |
2587 | * @filp: file pointer to tty | |
1da177e4 | 2588 | * |
af9b897e AC |
2589 | * tty_open and tty_release keep up the tty count that contains the |
2590 | * number of opens done on a tty. We cannot use the inode-count, as | |
2591 | * different inodes might point to the same tty. | |
1da177e4 | 2592 | * |
af9b897e AC |
2593 | * Open-counting is needed for pty masters, as well as for keeping |
2594 | * track of serial lines: DTR is dropped when the last close happens. | |
2595 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
2596 | * | |
2597 | * The termios state of a pty is reset on first open so that | |
2598 | * settings don't persist across reuse. | |
2599 | * | |
24ec839c PZ |
2600 | * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. |
2601 | * tty->count should protect the rest. | |
2602 | * ->siglock protects ->signal/->sighand | |
1da177e4 | 2603 | */ |
af9b897e | 2604 | |
37bdfb07 | 2605 | static int tty_open(struct inode *inode, struct file *filp) |
1da177e4 LT |
2606 | { |
2607 | struct tty_struct *tty; | |
2608 | int noctty, retval; | |
2609 | struct tty_driver *driver; | |
2610 | int index; | |
2611 | dev_t device = inode->i_rdev; | |
2612 | unsigned short saved_flags = filp->f_flags; | |
2613 | ||
2614 | nonseekable_open(inode, filp); | |
37bdfb07 | 2615 | |
1da177e4 LT |
2616 | retry_open: |
2617 | noctty = filp->f_flags & O_NOCTTY; | |
2618 | index = -1; | |
2619 | retval = 0; | |
37bdfb07 | 2620 | |
70522e12 | 2621 | mutex_lock(&tty_mutex); |
1da177e4 | 2622 | |
37bdfb07 | 2623 | if (device == MKDEV(TTYAUX_MAJOR, 0)) { |
24ec839c PZ |
2624 | tty = get_current_tty(); |
2625 | if (!tty) { | |
70522e12 | 2626 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2627 | return -ENXIO; |
2628 | } | |
24ec839c PZ |
2629 | driver = tty->driver; |
2630 | index = tty->index; | |
1da177e4 LT |
2631 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
2632 | /* noctty = 1; */ | |
2633 | goto got_driver; | |
2634 | } | |
2635 | #ifdef CONFIG_VT | |
37bdfb07 | 2636 | if (device == MKDEV(TTY_MAJOR, 0)) { |
1da177e4 LT |
2637 | extern struct tty_driver *console_driver; |
2638 | driver = console_driver; | |
2639 | index = fg_console; | |
2640 | noctty = 1; | |
2641 | goto got_driver; | |
2642 | } | |
2643 | #endif | |
37bdfb07 | 2644 | if (device == MKDEV(TTYAUX_MAJOR, 1)) { |
1da177e4 LT |
2645 | driver = console_device(&index); |
2646 | if (driver) { | |
2647 | /* Don't let /dev/console block */ | |
2648 | filp->f_flags |= O_NONBLOCK; | |
2649 | noctty = 1; | |
2650 | goto got_driver; | |
2651 | } | |
70522e12 | 2652 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2653 | return -ENODEV; |
2654 | } | |
2655 | ||
2656 | driver = get_tty_driver(device, &index); | |
2657 | if (!driver) { | |
70522e12 | 2658 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2659 | return -ENODEV; |
2660 | } | |
2661 | got_driver: | |
2662 | retval = init_dev(driver, index, &tty); | |
70522e12 | 2663 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2664 | if (retval) |
2665 | return retval; | |
2666 | ||
2667 | filp->private_data = tty; | |
2668 | file_move(filp, &tty->tty_files); | |
2669 | check_tty_count(tty, "tty_open"); | |
2670 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2671 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2672 | noctty = 1; | |
2673 | #ifdef TTY_DEBUG_HANGUP | |
2674 | printk(KERN_DEBUG "opening %s...", tty->name); | |
2675 | #endif | |
2676 | if (!retval) { | |
2677 | if (tty->driver->open) | |
2678 | retval = tty->driver->open(tty, filp); | |
2679 | else | |
2680 | retval = -ENODEV; | |
2681 | } | |
2682 | filp->f_flags = saved_flags; | |
2683 | ||
37bdfb07 AC |
2684 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && |
2685 | !capable(CAP_SYS_ADMIN)) | |
1da177e4 LT |
2686 | retval = -EBUSY; |
2687 | ||
2688 | if (retval) { | |
2689 | #ifdef TTY_DEBUG_HANGUP | |
2690 | printk(KERN_DEBUG "error %d in opening %s...", retval, | |
2691 | tty->name); | |
2692 | #endif | |
2693 | release_dev(filp); | |
2694 | if (retval != -ERESTARTSYS) | |
2695 | return retval; | |
2696 | if (signal_pending(current)) | |
2697 | return retval; | |
2698 | schedule(); | |
2699 | /* | |
2700 | * Need to reset f_op in case a hangup happened. | |
2701 | */ | |
2702 | if (filp->f_op == &hung_up_tty_fops) | |
2703 | filp->f_op = &tty_fops; | |
2704 | goto retry_open; | |
2705 | } | |
24ec839c PZ |
2706 | |
2707 | mutex_lock(&tty_mutex); | |
2708 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2709 | if (!noctty && |
2710 | current->signal->leader && | |
2711 | !current->signal->tty && | |
ab521dc0 | 2712 | tty->session == NULL) |
2a65f1d9 | 2713 | __proc_set_tty(current, tty); |
24ec839c PZ |
2714 | spin_unlock_irq(¤t->sighand->siglock); |
2715 | mutex_unlock(&tty_mutex); | |
522ed776 | 2716 | tty_audit_opening(); |
1da177e4 LT |
2717 | return 0; |
2718 | } | |
2719 | ||
2720 | #ifdef CONFIG_UNIX98_PTYS | |
af9b897e AC |
2721 | /** |
2722 | * ptmx_open - open a unix 98 pty master | |
2723 | * @inode: inode of device file | |
2724 | * @filp: file pointer to tty | |
2725 | * | |
2726 | * Allocate a unix98 pty master device from the ptmx driver. | |
2727 | * | |
2728 | * Locking: tty_mutex protects theinit_dev work. tty->count should | |
37bdfb07 | 2729 | * protect the rest. |
af9b897e AC |
2730 | * allocated_ptys_lock handles the list of free pty numbers |
2731 | */ | |
2732 | ||
37bdfb07 | 2733 | static int ptmx_open(struct inode *inode, struct file *filp) |
1da177e4 LT |
2734 | { |
2735 | struct tty_struct *tty; | |
2736 | int retval; | |
2737 | int index; | |
2738 | int idr_ret; | |
2739 | ||
2740 | nonseekable_open(inode, filp); | |
2741 | ||
2742 | /* find a device that is not in use. */ | |
a6752f3f | 2743 | mutex_lock(&allocated_ptys_lock); |
1da177e4 | 2744 | if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { |
a6752f3f | 2745 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2746 | return -ENOMEM; |
2747 | } | |
2748 | idr_ret = idr_get_new(&allocated_ptys, NULL, &index); | |
2749 | if (idr_ret < 0) { | |
a6752f3f | 2750 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2751 | if (idr_ret == -EAGAIN) |
2752 | return -ENOMEM; | |
2753 | return -EIO; | |
2754 | } | |
2755 | if (index >= pty_limit) { | |
2756 | idr_remove(&allocated_ptys, index); | |
a6752f3f | 2757 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2758 | return -EIO; |
2759 | } | |
a6752f3f | 2760 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 | 2761 | |
70522e12 | 2762 | mutex_lock(&tty_mutex); |
1da177e4 | 2763 | retval = init_dev(ptm_driver, index, &tty); |
70522e12 | 2764 | mutex_unlock(&tty_mutex); |
37bdfb07 | 2765 | |
1da177e4 LT |
2766 | if (retval) |
2767 | goto out; | |
2768 | ||
2769 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
2770 | filp->private_data = tty; | |
2771 | file_move(filp, &tty->tty_files); | |
2772 | ||
2773 | retval = -ENOMEM; | |
2774 | if (devpts_pty_new(tty->link)) | |
2775 | goto out1; | |
2776 | ||
2777 | check_tty_count(tty, "tty_open"); | |
2778 | retval = ptm_driver->open(tty, filp); | |
522ed776 MT |
2779 | if (!retval) { |
2780 | tty_audit_opening(); | |
1da177e4 | 2781 | return 0; |
522ed776 | 2782 | } |
1da177e4 LT |
2783 | out1: |
2784 | release_dev(filp); | |
9453a5ad | 2785 | return retval; |
1da177e4 | 2786 | out: |
a6752f3f | 2787 | mutex_lock(&allocated_ptys_lock); |
1da177e4 | 2788 | idr_remove(&allocated_ptys, index); |
a6752f3f | 2789 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2790 | return retval; |
2791 | } | |
2792 | #endif | |
2793 | ||
af9b897e AC |
2794 | /** |
2795 | * tty_release - vfs callback for close | |
2796 | * @inode: inode of tty | |
2797 | * @filp: file pointer for handle to tty | |
2798 | * | |
2799 | * Called the last time each file handle is closed that references | |
2800 | * this tty. There may however be several such references. | |
2801 | * | |
2802 | * Locking: | |
2803 | * Takes bkl. See release_dev | |
2804 | */ | |
2805 | ||
37bdfb07 | 2806 | static int tty_release(struct inode *inode, struct file *filp) |
1da177e4 LT |
2807 | { |
2808 | lock_kernel(); | |
2809 | release_dev(filp); | |
2810 | unlock_kernel(); | |
2811 | return 0; | |
2812 | } | |
2813 | ||
af9b897e AC |
2814 | /** |
2815 | * tty_poll - check tty status | |
2816 | * @filp: file being polled | |
2817 | * @wait: poll wait structures to update | |
2818 | * | |
2819 | * Call the line discipline polling method to obtain the poll | |
2820 | * status of the device. | |
2821 | * | |
2822 | * Locking: locks called line discipline but ldisc poll method | |
2823 | * may be re-entered freely by other callers. | |
2824 | */ | |
2825 | ||
37bdfb07 | 2826 | static unsigned int tty_poll(struct file *filp, poll_table *wait) |
1da177e4 | 2827 | { |
37bdfb07 | 2828 | struct tty_struct *tty; |
1da177e4 LT |
2829 | struct tty_ldisc *ld; |
2830 | int ret = 0; | |
2831 | ||
2832 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2833 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) |
1da177e4 | 2834 | return 0; |
37bdfb07 | 2835 | |
1da177e4 LT |
2836 | ld = tty_ldisc_ref_wait(tty); |
2837 | if (ld->poll) | |
2838 | ret = (ld->poll)(tty, filp, wait); | |
2839 | tty_ldisc_deref(ld); | |
2840 | return ret; | |
2841 | } | |
2842 | ||
37bdfb07 | 2843 | static int tty_fasync(int fd, struct file *filp, int on) |
1da177e4 | 2844 | { |
37bdfb07 | 2845 | struct tty_struct *tty; |
1da177e4 LT |
2846 | int retval; |
2847 | ||
2848 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2849 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) |
1da177e4 | 2850 | return 0; |
37bdfb07 | 2851 | |
1da177e4 LT |
2852 | retval = fasync_helper(fd, filp, on, &tty->fasync); |
2853 | if (retval <= 0) | |
2854 | return retval; | |
2855 | ||
2856 | if (on) { | |
ab521dc0 EB |
2857 | enum pid_type type; |
2858 | struct pid *pid; | |
1da177e4 LT |
2859 | if (!waitqueue_active(&tty->read_wait)) |
2860 | tty->minimum_to_wake = 1; | |
ab521dc0 EB |
2861 | if (tty->pgrp) { |
2862 | pid = tty->pgrp; | |
2863 | type = PIDTYPE_PGID; | |
2864 | } else { | |
2865 | pid = task_pid(current); | |
2866 | type = PIDTYPE_PID; | |
2867 | } | |
2868 | retval = __f_setown(filp, pid, type, 0); | |
1da177e4 LT |
2869 | if (retval) |
2870 | return retval; | |
2871 | } else { | |
2872 | if (!tty->fasync && !waitqueue_active(&tty->read_wait)) | |
2873 | tty->minimum_to_wake = N_TTY_BUF_SIZE; | |
2874 | } | |
2875 | return 0; | |
2876 | } | |
2877 | ||
af9b897e AC |
2878 | /** |
2879 | * tiocsti - fake input character | |
2880 | * @tty: tty to fake input into | |
2881 | * @p: pointer to character | |
2882 | * | |
3a4fa0a2 | 2883 | * Fake input to a tty device. Does the necessary locking and |
af9b897e AC |
2884 | * input management. |
2885 | * | |
2886 | * FIXME: does not honour flow control ?? | |
2887 | * | |
2888 | * Locking: | |
2889 | * Called functions take tty_ldisc_lock | |
2890 | * current->signal->tty check is safe without locks | |
28298232 AC |
2891 | * |
2892 | * FIXME: may race normal receive processing | |
af9b897e AC |
2893 | */ |
2894 | ||
1da177e4 LT |
2895 | static int tiocsti(struct tty_struct *tty, char __user *p) |
2896 | { | |
2897 | char ch, mbz = 0; | |
2898 | struct tty_ldisc *ld; | |
37bdfb07 | 2899 | |
1da177e4 LT |
2900 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) |
2901 | return -EPERM; | |
2902 | if (get_user(ch, p)) | |
2903 | return -EFAULT; | |
2904 | ld = tty_ldisc_ref_wait(tty); | |
2905 | ld->receive_buf(tty, &ch, &mbz, 1); | |
2906 | tty_ldisc_deref(ld); | |
2907 | return 0; | |
2908 | } | |
2909 | ||
af9b897e AC |
2910 | /** |
2911 | * tiocgwinsz - implement window query ioctl | |
2912 | * @tty; tty | |
2913 | * @arg: user buffer for result | |
2914 | * | |
808a0d38 | 2915 | * Copies the kernel idea of the window size into the user buffer. |
af9b897e | 2916 | * |
24ec839c | 2917 | * Locking: tty->termios_mutex is taken to ensure the winsize data |
808a0d38 | 2918 | * is consistent. |
af9b897e AC |
2919 | */ |
2920 | ||
37bdfb07 | 2921 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) |
1da177e4 | 2922 | { |
808a0d38 AC |
2923 | int err; |
2924 | ||
5785c95b | 2925 | mutex_lock(&tty->termios_mutex); |
808a0d38 | 2926 | err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); |
5785c95b | 2927 | mutex_unlock(&tty->termios_mutex); |
808a0d38 AC |
2928 | |
2929 | return err ? -EFAULT: 0; | |
1da177e4 LT |
2930 | } |
2931 | ||
af9b897e AC |
2932 | /** |
2933 | * tiocswinsz - implement window size set ioctl | |
2934 | * @tty; tty | |
2935 | * @arg: user buffer for result | |
2936 | * | |
2937 | * Copies the user idea of the window size to the kernel. Traditionally | |
2938 | * this is just advisory information but for the Linux console it | |
2939 | * actually has driver level meaning and triggers a VC resize. | |
2940 | * | |
2941 | * Locking: | |
ca9bda00 AC |
2942 | * Called function use the console_sem is used to ensure we do |
2943 | * not try and resize the console twice at once. | |
24ec839c PZ |
2944 | * The tty->termios_mutex is used to ensure we don't double |
2945 | * resize and get confused. Lock order - tty->termios_mutex before | |
ca9bda00 | 2946 | * console sem |
af9b897e AC |
2947 | */ |
2948 | ||
1da177e4 | 2949 | static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, |
37bdfb07 | 2950 | struct winsize __user *arg) |
1da177e4 LT |
2951 | { |
2952 | struct winsize tmp_ws; | |
2953 | ||
2954 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
2955 | return -EFAULT; | |
ca9bda00 | 2956 | |
5785c95b | 2957 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 2958 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
ca9bda00 AC |
2959 | goto done; |
2960 | ||
1da177e4 LT |
2961 | #ifdef CONFIG_VT |
2962 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { | |
5785c95b AV |
2963 | if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, |
2964 | tmp_ws.ws_row)) { | |
2965 | mutex_unlock(&tty->termios_mutex); | |
37bdfb07 | 2966 | return -ENXIO; |
ca9bda00 | 2967 | } |
1da177e4 LT |
2968 | } |
2969 | #endif | |
ab521dc0 EB |
2970 | if (tty->pgrp) |
2971 | kill_pgrp(tty->pgrp, SIGWINCH, 1); | |
2972 | if ((real_tty->pgrp != tty->pgrp) && real_tty->pgrp) | |
2973 | kill_pgrp(real_tty->pgrp, SIGWINCH, 1); | |
1da177e4 LT |
2974 | tty->winsize = tmp_ws; |
2975 | real_tty->winsize = tmp_ws; | |
ca9bda00 | 2976 | done: |
5785c95b | 2977 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
2978 | return 0; |
2979 | } | |
2980 | ||
af9b897e AC |
2981 | /** |
2982 | * tioccons - allow admin to move logical console | |
2983 | * @file: the file to become console | |
2984 | * | |
2985 | * Allow the adminstrator to move the redirected console device | |
2986 | * | |
2987 | * Locking: uses redirect_lock to guard the redirect information | |
2988 | */ | |
2989 | ||
1da177e4 LT |
2990 | static int tioccons(struct file *file) |
2991 | { | |
2992 | if (!capable(CAP_SYS_ADMIN)) | |
2993 | return -EPERM; | |
2994 | if (file->f_op->write == redirected_tty_write) { | |
2995 | struct file *f; | |
2996 | spin_lock(&redirect_lock); | |
2997 | f = redirect; | |
2998 | redirect = NULL; | |
2999 | spin_unlock(&redirect_lock); | |
3000 | if (f) | |
3001 | fput(f); | |
3002 | return 0; | |
3003 | } | |
3004 | spin_lock(&redirect_lock); | |
3005 | if (redirect) { | |
3006 | spin_unlock(&redirect_lock); | |
3007 | return -EBUSY; | |
3008 | } | |
3009 | get_file(file); | |
3010 | redirect = file; | |
3011 | spin_unlock(&redirect_lock); | |
3012 | return 0; | |
3013 | } | |
3014 | ||
af9b897e AC |
3015 | /** |
3016 | * fionbio - non blocking ioctl | |
3017 | * @file: file to set blocking value | |
3018 | * @p: user parameter | |
3019 | * | |
3020 | * Historical tty interfaces had a blocking control ioctl before | |
3021 | * the generic functionality existed. This piece of history is preserved | |
3022 | * in the expected tty API of posix OS's. | |
3023 | * | |
3024 | * Locking: none, the open fle handle ensures it won't go away. | |
3025 | */ | |
1da177e4 LT |
3026 | |
3027 | static int fionbio(struct file *file, int __user *p) | |
3028 | { | |
3029 | int nonblock; | |
3030 | ||
3031 | if (get_user(nonblock, p)) | |
3032 | return -EFAULT; | |
3033 | ||
3034 | if (nonblock) | |
3035 | file->f_flags |= O_NONBLOCK; | |
3036 | else | |
3037 | file->f_flags &= ~O_NONBLOCK; | |
3038 | return 0; | |
3039 | } | |
3040 | ||
af9b897e AC |
3041 | /** |
3042 | * tiocsctty - set controlling tty | |
3043 | * @tty: tty structure | |
3044 | * @arg: user argument | |
3045 | * | |
3046 | * This ioctl is used to manage job control. It permits a session | |
3047 | * leader to set this tty as the controlling tty for the session. | |
3048 | * | |
3049 | * Locking: | |
28298232 | 3050 | * Takes tty_mutex() to protect tty instance |
24ec839c PZ |
3051 | * Takes tasklist_lock internally to walk sessions |
3052 | * Takes ->siglock() when updating signal->tty | |
af9b897e AC |
3053 | */ |
3054 | ||
1da177e4 LT |
3055 | static int tiocsctty(struct tty_struct *tty, int arg) |
3056 | { | |
24ec839c | 3057 | int ret = 0; |
ab521dc0 | 3058 | if (current->signal->leader && (task_session(current) == tty->session)) |
24ec839c PZ |
3059 | return ret; |
3060 | ||
3061 | mutex_lock(&tty_mutex); | |
1da177e4 LT |
3062 | /* |
3063 | * The process must be a session leader and | |
3064 | * not have a controlling tty already. | |
3065 | */ | |
24ec839c PZ |
3066 | if (!current->signal->leader || current->signal->tty) { |
3067 | ret = -EPERM; | |
3068 | goto unlock; | |
3069 | } | |
3070 | ||
ab521dc0 | 3071 | if (tty->session) { |
1da177e4 LT |
3072 | /* |
3073 | * This tty is already the controlling | |
3074 | * tty for another session group! | |
3075 | */ | |
37bdfb07 | 3076 | if (arg == 1 && capable(CAP_SYS_ADMIN)) { |
1da177e4 LT |
3077 | /* |
3078 | * Steal it away | |
3079 | */ | |
1da177e4 | 3080 | read_lock(&tasklist_lock); |
24ec839c | 3081 | session_clear_tty(tty->session); |
1da177e4 | 3082 | read_unlock(&tasklist_lock); |
24ec839c PZ |
3083 | } else { |
3084 | ret = -EPERM; | |
3085 | goto unlock; | |
3086 | } | |
1da177e4 | 3087 | } |
24ec839c PZ |
3088 | proc_set_tty(current, tty); |
3089 | unlock: | |
28298232 | 3090 | mutex_unlock(&tty_mutex); |
24ec839c | 3091 | return ret; |
1da177e4 LT |
3092 | } |
3093 | ||
af9b897e AC |
3094 | /** |
3095 | * tiocgpgrp - get process group | |
3096 | * @tty: tty passed by user | |
3097 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3098 | * @p: returned pid | |
3099 | * | |
3100 | * Obtain the process group of the tty. If there is no process group | |
3101 | * return an error. | |
3102 | * | |
24ec839c | 3103 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3104 | */ |
3105 | ||
1da177e4 LT |
3106 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3107 | { | |
3108 | /* | |
3109 | * (tty == real_tty) is a cheap way of | |
3110 | * testing if the tty is NOT a master pty. | |
3111 | */ | |
3112 | if (tty == real_tty && current->signal->tty != real_tty) | |
3113 | return -ENOTTY; | |
b488893a | 3114 | return put_user(pid_vnr(real_tty->pgrp), p); |
1da177e4 LT |
3115 | } |
3116 | ||
af9b897e AC |
3117 | /** |
3118 | * tiocspgrp - attempt to set process group | |
3119 | * @tty: tty passed by user | |
3120 | * @real_tty: tty side device matching tty passed by user | |
3121 | * @p: pid pointer | |
3122 | * | |
3123 | * Set the process group of the tty to the session passed. Only | |
3124 | * permitted where the tty session is our session. | |
3125 | * | |
3126 | * Locking: None | |
af9b897e AC |
3127 | */ |
3128 | ||
1da177e4 LT |
3129 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3130 | { | |
04a2e6a5 EB |
3131 | struct pid *pgrp; |
3132 | pid_t pgrp_nr; | |
1da177e4 LT |
3133 | int retval = tty_check_change(real_tty); |
3134 | ||
3135 | if (retval == -EIO) | |
3136 | return -ENOTTY; | |
3137 | if (retval) | |
3138 | return retval; | |
3139 | if (!current->signal->tty || | |
3140 | (current->signal->tty != real_tty) || | |
ab521dc0 | 3141 | (real_tty->session != task_session(current))) |
1da177e4 | 3142 | return -ENOTTY; |
04a2e6a5 | 3143 | if (get_user(pgrp_nr, p)) |
1da177e4 | 3144 | return -EFAULT; |
04a2e6a5 | 3145 | if (pgrp_nr < 0) |
1da177e4 | 3146 | return -EINVAL; |
04a2e6a5 | 3147 | rcu_read_lock(); |
b488893a | 3148 | pgrp = find_vpid(pgrp_nr); |
04a2e6a5 EB |
3149 | retval = -ESRCH; |
3150 | if (!pgrp) | |
3151 | goto out_unlock; | |
3152 | retval = -EPERM; | |
3153 | if (session_of_pgrp(pgrp) != task_session(current)) | |
3154 | goto out_unlock; | |
3155 | retval = 0; | |
ab521dc0 EB |
3156 | put_pid(real_tty->pgrp); |
3157 | real_tty->pgrp = get_pid(pgrp); | |
04a2e6a5 EB |
3158 | out_unlock: |
3159 | rcu_read_unlock(); | |
3160 | return retval; | |
1da177e4 LT |
3161 | } |
3162 | ||
af9b897e AC |
3163 | /** |
3164 | * tiocgsid - get session id | |
3165 | * @tty: tty passed by user | |
3166 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3167 | * @p: pointer to returned session id | |
3168 | * | |
3169 | * Obtain the session id of the tty. If there is no session | |
3170 | * return an error. | |
3171 | * | |
24ec839c | 3172 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3173 | */ |
3174 | ||
1da177e4 LT |
3175 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3176 | { | |
3177 | /* | |
3178 | * (tty == real_tty) is a cheap way of | |
3179 | * testing if the tty is NOT a master pty. | |
3180 | */ | |
3181 | if (tty == real_tty && current->signal->tty != real_tty) | |
3182 | return -ENOTTY; | |
ab521dc0 | 3183 | if (!real_tty->session) |
1da177e4 | 3184 | return -ENOTTY; |
b488893a | 3185 | return put_user(pid_vnr(real_tty->session), p); |
1da177e4 LT |
3186 | } |
3187 | ||
af9b897e AC |
3188 | /** |
3189 | * tiocsetd - set line discipline | |
3190 | * @tty: tty device | |
3191 | * @p: pointer to user data | |
3192 | * | |
3193 | * Set the line discipline according to user request. | |
3194 | * | |
3195 | * Locking: see tty_set_ldisc, this function is just a helper | |
3196 | */ | |
3197 | ||
1da177e4 LT |
3198 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
3199 | { | |
3200 | int ldisc; | |
3201 | ||
3202 | if (get_user(ldisc, p)) | |
3203 | return -EFAULT; | |
3204 | return tty_set_ldisc(tty, ldisc); | |
3205 | } | |
3206 | ||
af9b897e AC |
3207 | /** |
3208 | * send_break - performed time break | |
3209 | * @tty: device to break on | |
3210 | * @duration: timeout in mS | |
3211 | * | |
3212 | * Perform a timed break on hardware that lacks its own driver level | |
3213 | * timed break functionality. | |
3214 | * | |
3215 | * Locking: | |
28298232 | 3216 | * atomic_write_lock serializes |
af9b897e | 3217 | * |
af9b897e AC |
3218 | */ |
3219 | ||
b20f3ae5 | 3220 | static int send_break(struct tty_struct *tty, unsigned int duration) |
1da177e4 | 3221 | { |
9c1729db | 3222 | if (tty_write_lock(tty, 0) < 0) |
28298232 | 3223 | return -EINTR; |
1da177e4 | 3224 | tty->driver->break_ctl(tty, -1); |
9c1729db | 3225 | if (!signal_pending(current)) |
b20f3ae5 | 3226 | msleep_interruptible(duration); |
1da177e4 | 3227 | tty->driver->break_ctl(tty, 0); |
9c1729db | 3228 | tty_write_unlock(tty); |
1da177e4 LT |
3229 | if (signal_pending(current)) |
3230 | return -EINTR; | |
3231 | return 0; | |
3232 | } | |
3233 | ||
af9b897e AC |
3234 | /** |
3235 | * tiocmget - get modem status | |
3236 | * @tty: tty device | |
3237 | * @file: user file pointer | |
3238 | * @p: pointer to result | |
3239 | * | |
3240 | * Obtain the modem status bits from the tty driver if the feature | |
3241 | * is supported. Return -EINVAL if it is not available. | |
3242 | * | |
3243 | * Locking: none (up to the driver) | |
3244 | */ | |
3245 | ||
3246 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) | |
1da177e4 LT |
3247 | { |
3248 | int retval = -EINVAL; | |
3249 | ||
3250 | if (tty->driver->tiocmget) { | |
3251 | retval = tty->driver->tiocmget(tty, file); | |
3252 | ||
3253 | if (retval >= 0) | |
3254 | retval = put_user(retval, p); | |
3255 | } | |
3256 | return retval; | |
3257 | } | |
3258 | ||
af9b897e AC |
3259 | /** |
3260 | * tiocmset - set modem status | |
3261 | * @tty: tty device | |
3262 | * @file: user file pointer | |
3263 | * @cmd: command - clear bits, set bits or set all | |
3264 | * @p: pointer to desired bits | |
3265 | * | |
3266 | * Set the modem status bits from the tty driver if the feature | |
3267 | * is supported. Return -EINVAL if it is not available. | |
3268 | * | |
3269 | * Locking: none (up to the driver) | |
3270 | */ | |
3271 | ||
3272 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, | |
1da177e4 LT |
3273 | unsigned __user *p) |
3274 | { | |
3275 | int retval = -EINVAL; | |
3276 | ||
3277 | if (tty->driver->tiocmset) { | |
3278 | unsigned int set, clear, val; | |
3279 | ||
3280 | retval = get_user(val, p); | |
3281 | if (retval) | |
3282 | return retval; | |
3283 | ||
3284 | set = clear = 0; | |
3285 | switch (cmd) { | |
3286 | case TIOCMBIS: | |
3287 | set = val; | |
3288 | break; | |
3289 | case TIOCMBIC: | |
3290 | clear = val; | |
3291 | break; | |
3292 | case TIOCMSET: | |
3293 | set = val; | |
3294 | clear = ~val; | |
3295 | break; | |
3296 | } | |
3297 | ||
3298 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3299 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3300 | ||
3301 | retval = tty->driver->tiocmset(tty, file, set, clear); | |
3302 | } | |
3303 | return retval; | |
3304 | } | |
3305 | ||
3306 | /* | |
3307 | * Split this up, as gcc can choke on it otherwise.. | |
3308 | */ | |
37bdfb07 | 3309 | int tty_ioctl(struct inode *inode, struct file *file, |
1da177e4 LT |
3310 | unsigned int cmd, unsigned long arg) |
3311 | { | |
3312 | struct tty_struct *tty, *real_tty; | |
3313 | void __user *p = (void __user *)arg; | |
3314 | int retval; | |
3315 | struct tty_ldisc *ld; | |
37bdfb07 | 3316 | |
1da177e4 LT |
3317 | tty = (struct tty_struct *)file->private_data; |
3318 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3319 | return -EINVAL; | |
3320 | ||
28298232 AC |
3321 | /* CHECKME: is this safe as one end closes ? */ |
3322 | ||
1da177e4 LT |
3323 | real_tty = tty; |
3324 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
3325 | tty->driver->subtype == PTY_TYPE_MASTER) | |
3326 | real_tty = tty->link; | |
3327 | ||
3328 | /* | |
3329 | * Break handling by driver | |
3330 | */ | |
3331 | if (!tty->driver->break_ctl) { | |
37bdfb07 | 3332 | switch (cmd) { |
1da177e4 LT |
3333 | case TIOCSBRK: |
3334 | case TIOCCBRK: | |
3335 | if (tty->driver->ioctl) | |
3336 | return tty->driver->ioctl(tty, file, cmd, arg); | |
3337 | return -EINVAL; | |
37bdfb07 | 3338 | |
1da177e4 LT |
3339 | /* These two ioctl's always return success; even if */ |
3340 | /* the driver doesn't support them. */ | |
3341 | case TCSBRK: | |
3342 | case TCSBRKP: | |
3343 | if (!tty->driver->ioctl) | |
3344 | return 0; | |
3345 | retval = tty->driver->ioctl(tty, file, cmd, arg); | |
3346 | if (retval == -ENOIOCTLCMD) | |
3347 | retval = 0; | |
3348 | return retval; | |
3349 | } | |
3350 | } | |
3351 | ||
3352 | /* | |
3353 | * Factor out some common prep work | |
3354 | */ | |
3355 | switch (cmd) { | |
3356 | case TIOCSETD: | |
3357 | case TIOCSBRK: | |
3358 | case TIOCCBRK: | |
3359 | case TCSBRK: | |
37bdfb07 | 3360 | case TCSBRKP: |
1da177e4 LT |
3361 | retval = tty_check_change(tty); |
3362 | if (retval) | |
3363 | return retval; | |
3364 | if (cmd != TIOCCBRK) { | |
3365 | tty_wait_until_sent(tty, 0); | |
3366 | if (signal_pending(current)) | |
3367 | return -EINTR; | |
3368 | } | |
3369 | break; | |
3370 | } | |
3371 | ||
3372 | switch (cmd) { | |
37bdfb07 AC |
3373 | case TIOCSTI: |
3374 | return tiocsti(tty, p); | |
3375 | case TIOCGWINSZ: | |
3376 | return tiocgwinsz(tty, p); | |
3377 | case TIOCSWINSZ: | |
3378 | return tiocswinsz(tty, real_tty, p); | |
3379 | case TIOCCONS: | |
3380 | return real_tty != tty ? -EINVAL : tioccons(file); | |
3381 | case FIONBIO: | |
3382 | return fionbio(file, p); | |
3383 | case TIOCEXCL: | |
3384 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
3385 | return 0; | |
3386 | case TIOCNXCL: | |
3387 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
3388 | return 0; | |
3389 | case TIOCNOTTY: | |
3390 | if (current->signal->tty != tty) | |
3391 | return -ENOTTY; | |
3392 | no_tty(); | |
3393 | return 0; | |
3394 | case TIOCSCTTY: | |
3395 | return tiocsctty(tty, arg); | |
3396 | case TIOCGPGRP: | |
3397 | return tiocgpgrp(tty, real_tty, p); | |
3398 | case TIOCSPGRP: | |
3399 | return tiocspgrp(tty, real_tty, p); | |
3400 | case TIOCGSID: | |
3401 | return tiocgsid(tty, real_tty, p); | |
3402 | case TIOCGETD: | |
3403 | /* FIXME: check this is ok */ | |
3404 | return put_user(tty->ldisc.num, (int __user *)p); | |
3405 | case TIOCSETD: | |
3406 | return tiocsetd(tty, p); | |
1da177e4 | 3407 | #ifdef CONFIG_VT |
37bdfb07 AC |
3408 | case TIOCLINUX: |
3409 | return tioclinux(tty, arg); | |
1da177e4 | 3410 | #endif |
37bdfb07 AC |
3411 | /* |
3412 | * Break handling | |
3413 | */ | |
3414 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
3415 | tty->driver->break_ctl(tty, -1); | |
3416 | return 0; | |
1da177e4 | 3417 | |
37bdfb07 AC |
3418 | case TIOCCBRK: /* Turn break off, unconditionally */ |
3419 | tty->driver->break_ctl(tty, 0); | |
3420 | return 0; | |
3421 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
3422 | /* non-zero arg means wait for all output data | |
3423 | * to be sent (performed above) but don't send break. | |
3424 | * This is used by the tcdrain() termios function. | |
3425 | */ | |
3426 | if (!arg) | |
3427 | return send_break(tty, 250); | |
3428 | return 0; | |
3429 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
3430 | return send_break(tty, arg ? arg*100 : 250); | |
3431 | ||
3432 | case TIOCMGET: | |
3433 | return tty_tiocmget(tty, file, p); | |
3434 | case TIOCMSET: | |
3435 | case TIOCMBIC: | |
3436 | case TIOCMBIS: | |
3437 | return tty_tiocmset(tty, file, cmd, p); | |
3438 | case TCFLSH: | |
3439 | switch (arg) { | |
3440 | case TCIFLUSH: | |
3441 | case TCIOFLUSH: | |
3442 | /* flush tty buffer and allow ldisc to process ioctl */ | |
3443 | tty_buffer_flush(tty); | |
c5c34d48 | 3444 | break; |
37bdfb07 AC |
3445 | } |
3446 | break; | |
1da177e4 LT |
3447 | } |
3448 | if (tty->driver->ioctl) { | |
3449 | retval = (tty->driver->ioctl)(tty, file, cmd, arg); | |
3450 | if (retval != -ENOIOCTLCMD) | |
3451 | return retval; | |
3452 | } | |
3453 | ld = tty_ldisc_ref_wait(tty); | |
3454 | retval = -EINVAL; | |
3455 | if (ld->ioctl) { | |
3456 | retval = ld->ioctl(tty, file, cmd, arg); | |
3457 | if (retval == -ENOIOCTLCMD) | |
3458 | retval = -EINVAL; | |
3459 | } | |
3460 | tty_ldisc_deref(ld); | |
3461 | return retval; | |
3462 | } | |
3463 | ||
e10cc1df | 3464 | #ifdef CONFIG_COMPAT |
37bdfb07 | 3465 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
e10cc1df PF |
3466 | unsigned long arg) |
3467 | { | |
3468 | struct inode *inode = file->f_dentry->d_inode; | |
3469 | struct tty_struct *tty = file->private_data; | |
3470 | struct tty_ldisc *ld; | |
3471 | int retval = -ENOIOCTLCMD; | |
3472 | ||
3473 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3474 | return -EINVAL; | |
3475 | ||
3476 | if (tty->driver->compat_ioctl) { | |
3477 | retval = (tty->driver->compat_ioctl)(tty, file, cmd, arg); | |
3478 | if (retval != -ENOIOCTLCMD) | |
3479 | return retval; | |
3480 | } | |
3481 | ||
3482 | ld = tty_ldisc_ref_wait(tty); | |
3483 | if (ld->compat_ioctl) | |
3484 | retval = ld->compat_ioctl(tty, file, cmd, arg); | |
3485 | tty_ldisc_deref(ld); | |
3486 | ||
3487 | return retval; | |
3488 | } | |
3489 | #endif | |
1da177e4 LT |
3490 | |
3491 | /* | |
3492 | * This implements the "Secure Attention Key" --- the idea is to | |
3493 | * prevent trojan horses by killing all processes associated with this | |
3494 | * tty when the user hits the "Secure Attention Key". Required for | |
3495 | * super-paranoid applications --- see the Orange Book for more details. | |
37bdfb07 | 3496 | * |
1da177e4 LT |
3497 | * This code could be nicer; ideally it should send a HUP, wait a few |
3498 | * seconds, then send a INT, and then a KILL signal. But you then | |
3499 | * have to coordinate with the init process, since all processes associated | |
3500 | * with the current tty must be dead before the new getty is allowed | |
3501 | * to spawn. | |
3502 | * | |
3503 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
3504 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
3505 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
3506 | * | |
3507 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
3508 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
3509 | */ | |
8b6312f4 | 3510 | void __do_SAK(struct tty_struct *tty) |
1da177e4 LT |
3511 | { |
3512 | #ifdef TTY_SOFT_SAK | |
3513 | tty_hangup(tty); | |
3514 | #else | |
652486fb | 3515 | struct task_struct *g, *p; |
ab521dc0 | 3516 | struct pid *session; |
1da177e4 LT |
3517 | int i; |
3518 | struct file *filp; | |
badf1662 | 3519 | struct fdtable *fdt; |
37bdfb07 | 3520 | |
1da177e4 LT |
3521 | if (!tty) |
3522 | return; | |
24ec839c | 3523 | session = tty->session; |
37bdfb07 | 3524 | |
b3f13deb | 3525 | tty_ldisc_flush(tty); |
1da177e4 LT |
3526 | |
3527 | if (tty->driver->flush_buffer) | |
3528 | tty->driver->flush_buffer(tty); | |
37bdfb07 | 3529 | |
1da177e4 | 3530 | read_lock(&tasklist_lock); |
652486fb | 3531 | /* Kill the entire session */ |
ab521dc0 | 3532 | do_each_pid_task(session, PIDTYPE_SID, p) { |
652486fb | 3533 | printk(KERN_NOTICE "SAK: killed process %d" |
a47afb0f | 3534 | " (%s): task_session_nr(p)==tty->session\n", |
ba25f9dc | 3535 | task_pid_nr(p), p->comm); |
652486fb | 3536 | send_sig(SIGKILL, p, 1); |
ab521dc0 | 3537 | } while_each_pid_task(session, PIDTYPE_SID, p); |
652486fb EB |
3538 | /* Now kill any processes that happen to have the |
3539 | * tty open. | |
3540 | */ | |
3541 | do_each_thread(g, p) { | |
3542 | if (p->signal->tty == tty) { | |
1da177e4 | 3543 | printk(KERN_NOTICE "SAK: killed process %d" |
a47afb0f | 3544 | " (%s): task_session_nr(p)==tty->session\n", |
ba25f9dc | 3545 | task_pid_nr(p), p->comm); |
1da177e4 LT |
3546 | send_sig(SIGKILL, p, 1); |
3547 | continue; | |
3548 | } | |
3549 | task_lock(p); | |
3550 | if (p->files) { | |
ca99c1da DS |
3551 | /* |
3552 | * We don't take a ref to the file, so we must | |
3553 | * hold ->file_lock instead. | |
3554 | */ | |
3555 | spin_lock(&p->files->file_lock); | |
badf1662 | 3556 | fdt = files_fdtable(p->files); |
37bdfb07 | 3557 | for (i = 0; i < fdt->max_fds; i++) { |
1da177e4 LT |
3558 | filp = fcheck_files(p->files, i); |
3559 | if (!filp) | |
3560 | continue; | |
3561 | if (filp->f_op->read == tty_read && | |
3562 | filp->private_data == tty) { | |
3563 | printk(KERN_NOTICE "SAK: killed process %d" | |
3564 | " (%s): fd#%d opened to the tty\n", | |
ba25f9dc | 3565 | task_pid_nr(p), p->comm, i); |
20ac9437 | 3566 | force_sig(SIGKILL, p); |
1da177e4 LT |
3567 | break; |
3568 | } | |
3569 | } | |
ca99c1da | 3570 | spin_unlock(&p->files->file_lock); |
1da177e4 LT |
3571 | } |
3572 | task_unlock(p); | |
652486fb | 3573 | } while_each_thread(g, p); |
1da177e4 LT |
3574 | read_unlock(&tasklist_lock); |
3575 | #endif | |
3576 | } | |
3577 | ||
8b6312f4 EB |
3578 | static void do_SAK_work(struct work_struct *work) |
3579 | { | |
3580 | struct tty_struct *tty = | |
3581 | container_of(work, struct tty_struct, SAK_work); | |
3582 | __do_SAK(tty); | |
3583 | } | |
3584 | ||
1da177e4 LT |
3585 | /* |
3586 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
3587 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
3588 | * the values which we write to it will be identical to the values which it | |
3589 | * already has. --akpm | |
3590 | */ | |
3591 | void do_SAK(struct tty_struct *tty) | |
3592 | { | |
3593 | if (!tty) | |
3594 | return; | |
1da177e4 LT |
3595 | schedule_work(&tty->SAK_work); |
3596 | } | |
3597 | ||
3598 | EXPORT_SYMBOL(do_SAK); | |
3599 | ||
af9b897e AC |
3600 | /** |
3601 | * flush_to_ldisc | |
65f27f38 | 3602 | * @work: tty structure passed from work queue. |
af9b897e AC |
3603 | * |
3604 | * This routine is called out of the software interrupt to flush data | |
3605 | * from the buffer chain to the line discipline. | |
3606 | * | |
3607 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
3608 | * while invoking the line discipline receive_buf method. The | |
3609 | * receive_buf method is single threaded for each tty instance. | |
1da177e4 | 3610 | */ |
37bdfb07 | 3611 | |
65f27f38 | 3612 | static void flush_to_ldisc(struct work_struct *work) |
1da177e4 | 3613 | { |
65f27f38 DH |
3614 | struct tty_struct *tty = |
3615 | container_of(work, struct tty_struct, buf.work.work); | |
1da177e4 LT |
3616 | unsigned long flags; |
3617 | struct tty_ldisc *disc; | |
2c3bb20f | 3618 | struct tty_buffer *tbuf, *head; |
8977d929 PF |
3619 | char *char_buf; |
3620 | unsigned char *flag_buf; | |
1da177e4 LT |
3621 | |
3622 | disc = tty_ldisc_ref(tty); | |
3623 | if (disc == NULL) /* !TTY_LDISC */ | |
3624 | return; | |
3625 | ||
808249ce | 3626 | spin_lock_irqsave(&tty->buf.lock, flags); |
37bdfb07 AC |
3627 | /* So we know a flush is running */ |
3628 | set_bit(TTY_FLUSHING, &tty->flags); | |
2c3bb20f PF |
3629 | head = tty->buf.head; |
3630 | if (head != NULL) { | |
3631 | tty->buf.head = NULL; | |
3632 | for (;;) { | |
3633 | int count = head->commit - head->read; | |
3634 | if (!count) { | |
3635 | if (head->next == NULL) | |
3636 | break; | |
3637 | tbuf = head; | |
3638 | head = head->next; | |
3639 | tty_buffer_free(tty, tbuf); | |
3640 | continue; | |
3641 | } | |
42fd552e AC |
3642 | /* Ldisc or user is trying to flush the buffers |
3643 | we are feeding to the ldisc, stop feeding the | |
3644 | line discipline as we want to empty the queue */ | |
3645 | if (test_bit(TTY_FLUSHPENDING, &tty->flags)) | |
3646 | break; | |
2c3bb20f PF |
3647 | if (!tty->receive_room) { |
3648 | schedule_delayed_work(&tty->buf.work, 1); | |
3649 | break; | |
3650 | } | |
3651 | if (count > tty->receive_room) | |
3652 | count = tty->receive_room; | |
3653 | char_buf = head->char_buf_ptr + head->read; | |
3654 | flag_buf = head->flag_buf_ptr + head->read; | |
3655 | head->read += count; | |
8977d929 PF |
3656 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3657 | disc->receive_buf(tty, char_buf, flag_buf, count); | |
3658 | spin_lock_irqsave(&tty->buf.lock, flags); | |
3659 | } | |
42fd552e | 3660 | /* Restore the queue head */ |
2c3bb20f | 3661 | tty->buf.head = head; |
33f0f88f | 3662 | } |
42fd552e AC |
3663 | /* We may have a deferred request to flush the input buffer, |
3664 | if so pull the chain under the lock and empty the queue */ | |
3665 | if (test_bit(TTY_FLUSHPENDING, &tty->flags)) { | |
3666 | __tty_buffer_flush(tty); | |
3667 | clear_bit(TTY_FLUSHPENDING, &tty->flags); | |
3668 | wake_up(&tty->read_wait); | |
3669 | } | |
3670 | clear_bit(TTY_FLUSHING, &tty->flags); | |
808249ce | 3671 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
817d6d3b | 3672 | |
1da177e4 LT |
3673 | tty_ldisc_deref(disc); |
3674 | } | |
3675 | ||
1da177e4 LT |
3676 | /** |
3677 | * tty_flip_buffer_push - terminal | |
3678 | * @tty: tty to push | |
3679 | * | |
3680 | * Queue a push of the terminal flip buffers to the line discipline. This | |
3681 | * function must not be called from IRQ context if tty->low_latency is set. | |
3682 | * | |
3683 | * In the event of the queue being busy for flipping the work will be | |
3684 | * held off and retried later. | |
af9b897e AC |
3685 | * |
3686 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
1da177e4 LT |
3687 | */ |
3688 | ||
3689 | void tty_flip_buffer_push(struct tty_struct *tty) | |
3690 | { | |
808249ce PF |
3691 | unsigned long flags; |
3692 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 3693 | if (tty->buf.tail != NULL) |
8977d929 | 3694 | tty->buf.tail->commit = tty->buf.tail->used; |
808249ce PF |
3695 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3696 | ||
1da177e4 | 3697 | if (tty->low_latency) |
65f27f38 | 3698 | flush_to_ldisc(&tty->buf.work.work); |
1da177e4 | 3699 | else |
33f0f88f | 3700 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
3701 | } |
3702 | ||
3703 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
3704 | ||
33f0f88f | 3705 | |
af9b897e AC |
3706 | /** |
3707 | * initialize_tty_struct | |
3708 | * @tty: tty to initialize | |
3709 | * | |
3710 | * This subroutine initializes a tty structure that has been newly | |
3711 | * allocated. | |
3712 | * | |
3713 | * Locking: none - tty in question must not be exposed at this point | |
1da177e4 | 3714 | */ |
af9b897e | 3715 | |
1da177e4 LT |
3716 | static void initialize_tty_struct(struct tty_struct *tty) |
3717 | { | |
3718 | memset(tty, 0, sizeof(struct tty_struct)); | |
3719 | tty->magic = TTY_MAGIC; | |
3720 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
ab521dc0 EB |
3721 | tty->session = NULL; |
3722 | tty->pgrp = NULL; | |
1da177e4 | 3723 | tty->overrun_time = jiffies; |
33f0f88f AC |
3724 | tty->buf.head = tty->buf.tail = NULL; |
3725 | tty_buffer_init(tty); | |
65f27f38 | 3726 | INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); |
5785c95b | 3727 | mutex_init(&tty->termios_mutex); |
1da177e4 LT |
3728 | init_waitqueue_head(&tty->write_wait); |
3729 | init_waitqueue_head(&tty->read_wait); | |
65f27f38 | 3730 | INIT_WORK(&tty->hangup_work, do_tty_hangup); |
70522e12 IM |
3731 | mutex_init(&tty->atomic_read_lock); |
3732 | mutex_init(&tty->atomic_write_lock); | |
1da177e4 LT |
3733 | spin_lock_init(&tty->read_lock); |
3734 | INIT_LIST_HEAD(&tty->tty_files); | |
7f1f86a0 | 3735 | INIT_WORK(&tty->SAK_work, do_SAK_work); |
1da177e4 LT |
3736 | } |
3737 | ||
3738 | /* | |
3739 | * The default put_char routine if the driver did not define one. | |
3740 | */ | |
af9b897e | 3741 | |
1da177e4 LT |
3742 | static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) |
3743 | { | |
3744 | tty->driver->write(tty, &ch, 1); | |
3745 | } | |
3746 | ||
7fe845d1 | 3747 | static struct class *tty_class; |
1da177e4 LT |
3748 | |
3749 | /** | |
af9b897e AC |
3750 | * tty_register_device - register a tty device |
3751 | * @driver: the tty driver that describes the tty device | |
3752 | * @index: the index in the tty driver for this tty device | |
3753 | * @device: a struct device that is associated with this tty device. | |
3754 | * This field is optional, if there is no known struct device | |
3755 | * for this tty device it can be set to NULL safely. | |
1da177e4 | 3756 | * |
01107d34 GKH |
3757 | * Returns a pointer to the struct device for this tty device |
3758 | * (or ERR_PTR(-EFOO) on error). | |
1cdcb6b4 | 3759 | * |
af9b897e AC |
3760 | * This call is required to be made to register an individual tty device |
3761 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
3762 | * that bit is not set, this function should not be called by a tty | |
3763 | * driver. | |
3764 | * | |
3765 | * Locking: ?? | |
1da177e4 | 3766 | */ |
af9b897e | 3767 | |
01107d34 GKH |
3768 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
3769 | struct device *device) | |
1da177e4 LT |
3770 | { |
3771 | char name[64]; | |
3772 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; | |
3773 | ||
3774 | if (index >= driver->num) { | |
3775 | printk(KERN_ERR "Attempt to register invalid tty line number " | |
3776 | " (%d).\n", index); | |
1cdcb6b4 | 3777 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
3778 | } |
3779 | ||
1da177e4 LT |
3780 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
3781 | pty_line_name(driver, index, name); | |
3782 | else | |
3783 | tty_line_name(driver, index, name); | |
1cdcb6b4 | 3784 | |
01107d34 | 3785 | return device_create(tty_class, device, dev, name); |
1da177e4 LT |
3786 | } |
3787 | ||
3788 | /** | |
af9b897e AC |
3789 | * tty_unregister_device - unregister a tty device |
3790 | * @driver: the tty driver that describes the tty device | |
3791 | * @index: the index in the tty driver for this tty device | |
1da177e4 | 3792 | * |
af9b897e AC |
3793 | * If a tty device is registered with a call to tty_register_device() then |
3794 | * this function must be called when the tty device is gone. | |
3795 | * | |
3796 | * Locking: ?? | |
1da177e4 | 3797 | */ |
af9b897e | 3798 | |
1da177e4 LT |
3799 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
3800 | { | |
37bdfb07 AC |
3801 | device_destroy(tty_class, |
3802 | MKDEV(driver->major, driver->minor_start) + index); | |
1da177e4 LT |
3803 | } |
3804 | ||
3805 | EXPORT_SYMBOL(tty_register_device); | |
3806 | EXPORT_SYMBOL(tty_unregister_device); | |
3807 | ||
3808 | struct tty_driver *alloc_tty_driver(int lines) | |
3809 | { | |
3810 | struct tty_driver *driver; | |
3811 | ||
506eb99a | 3812 | driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); |
1da177e4 | 3813 | if (driver) { |
1da177e4 LT |
3814 | driver->magic = TTY_DRIVER_MAGIC; |
3815 | driver->num = lines; | |
3816 | /* later we'll move allocation of tables here */ | |
3817 | } | |
3818 | return driver; | |
3819 | } | |
3820 | ||
3821 | void put_tty_driver(struct tty_driver *driver) | |
3822 | { | |
3823 | kfree(driver); | |
3824 | } | |
3825 | ||
b68e31d0 JD |
3826 | void tty_set_operations(struct tty_driver *driver, |
3827 | const struct tty_operations *op) | |
1da177e4 LT |
3828 | { |
3829 | driver->open = op->open; | |
3830 | driver->close = op->close; | |
3831 | driver->write = op->write; | |
3832 | driver->put_char = op->put_char; | |
3833 | driver->flush_chars = op->flush_chars; | |
3834 | driver->write_room = op->write_room; | |
3835 | driver->chars_in_buffer = op->chars_in_buffer; | |
3836 | driver->ioctl = op->ioctl; | |
e10cc1df | 3837 | driver->compat_ioctl = op->compat_ioctl; |
1da177e4 LT |
3838 | driver->set_termios = op->set_termios; |
3839 | driver->throttle = op->throttle; | |
3840 | driver->unthrottle = op->unthrottle; | |
3841 | driver->stop = op->stop; | |
3842 | driver->start = op->start; | |
3843 | driver->hangup = op->hangup; | |
3844 | driver->break_ctl = op->break_ctl; | |
3845 | driver->flush_buffer = op->flush_buffer; | |
3846 | driver->set_ldisc = op->set_ldisc; | |
3847 | driver->wait_until_sent = op->wait_until_sent; | |
3848 | driver->send_xchar = op->send_xchar; | |
3849 | driver->read_proc = op->read_proc; | |
3850 | driver->write_proc = op->write_proc; | |
3851 | driver->tiocmget = op->tiocmget; | |
3852 | driver->tiocmset = op->tiocmset; | |
3853 | } | |
3854 | ||
3855 | ||
3856 | EXPORT_SYMBOL(alloc_tty_driver); | |
3857 | EXPORT_SYMBOL(put_tty_driver); | |
3858 | EXPORT_SYMBOL(tty_set_operations); | |
3859 | ||
3860 | /* | |
3861 | * Called by a tty driver to register itself. | |
3862 | */ | |
3863 | int tty_register_driver(struct tty_driver *driver) | |
3864 | { | |
3865 | int error; | |
37bdfb07 | 3866 | int i; |
1da177e4 LT |
3867 | dev_t dev; |
3868 | void **p = NULL; | |
3869 | ||
3870 | if (driver->flags & TTY_DRIVER_INSTALLED) | |
3871 | return 0; | |
3872 | ||
543691a6 AW |
3873 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { |
3874 | p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); | |
1da177e4 LT |
3875 | if (!p) |
3876 | return -ENOMEM; | |
1da177e4 LT |
3877 | } |
3878 | ||
3879 | if (!driver->major) { | |
37bdfb07 AC |
3880 | error = alloc_chrdev_region(&dev, driver->minor_start, |
3881 | driver->num, driver->name); | |
1da177e4 LT |
3882 | if (!error) { |
3883 | driver->major = MAJOR(dev); | |
3884 | driver->minor_start = MINOR(dev); | |
3885 | } | |
3886 | } else { | |
3887 | dev = MKDEV(driver->major, driver->minor_start); | |
e5717c48 | 3888 | error = register_chrdev_region(dev, driver->num, driver->name); |
1da177e4 LT |
3889 | } |
3890 | if (error < 0) { | |
3891 | kfree(p); | |
3892 | return error; | |
3893 | } | |
3894 | ||
3895 | if (p) { | |
3896 | driver->ttys = (struct tty_struct **)p; | |
edc6afc5 | 3897 | driver->termios = (struct ktermios **)(p + driver->num); |
37bdfb07 AC |
3898 | driver->termios_locked = (struct ktermios **) |
3899 | (p + driver->num * 2); | |
1da177e4 LT |
3900 | } else { |
3901 | driver->ttys = NULL; | |
3902 | driver->termios = NULL; | |
3903 | driver->termios_locked = NULL; | |
3904 | } | |
3905 | ||
3906 | cdev_init(&driver->cdev, &tty_fops); | |
3907 | driver->cdev.owner = driver->owner; | |
3908 | error = cdev_add(&driver->cdev, dev, driver->num); | |
3909 | if (error) { | |
1da177e4 LT |
3910 | unregister_chrdev_region(dev, driver->num); |
3911 | driver->ttys = NULL; | |
3912 | driver->termios = driver->termios_locked = NULL; | |
3913 | kfree(p); | |
3914 | return error; | |
3915 | } | |
3916 | ||
3917 | if (!driver->put_char) | |
3918 | driver->put_char = tty_default_put_char; | |
37bdfb07 | 3919 | |
ca509f69 | 3920 | mutex_lock(&tty_mutex); |
1da177e4 | 3921 | list_add(&driver->tty_drivers, &tty_drivers); |
ca509f69 | 3922 | mutex_unlock(&tty_mutex); |
37bdfb07 AC |
3923 | |
3924 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { | |
3925 | for (i = 0; i < driver->num; i++) | |
1da177e4 LT |
3926 | tty_register_device(driver, i, NULL); |
3927 | } | |
3928 | proc_tty_register_driver(driver); | |
3929 | return 0; | |
3930 | } | |
3931 | ||
3932 | EXPORT_SYMBOL(tty_register_driver); | |
3933 | ||
3934 | /* | |
3935 | * Called by a tty driver to unregister itself. | |
3936 | */ | |
3937 | int tty_unregister_driver(struct tty_driver *driver) | |
3938 | { | |
3939 | int i; | |
edc6afc5 | 3940 | struct ktermios *tp; |
1da177e4 LT |
3941 | void *p; |
3942 | ||
3943 | if (driver->refcount) | |
3944 | return -EBUSY; | |
3945 | ||
3946 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
3947 | driver->num); | |
ca509f69 | 3948 | mutex_lock(&tty_mutex); |
1da177e4 | 3949 | list_del(&driver->tty_drivers); |
ca509f69 | 3950 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
3951 | |
3952 | /* | |
3953 | * Free the termios and termios_locked structures because | |
3954 | * we don't want to get memory leaks when modular tty | |
3955 | * drivers are removed from the kernel. | |
3956 | */ | |
3957 | for (i = 0; i < driver->num; i++) { | |
3958 | tp = driver->termios[i]; | |
3959 | if (tp) { | |
3960 | driver->termios[i] = NULL; | |
3961 | kfree(tp); | |
3962 | } | |
3963 | tp = driver->termios_locked[i]; | |
3964 | if (tp) { | |
3965 | driver->termios_locked[i] = NULL; | |
3966 | kfree(tp); | |
3967 | } | |
331b8319 | 3968 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
1da177e4 LT |
3969 | tty_unregister_device(driver, i); |
3970 | } | |
3971 | p = driver->ttys; | |
3972 | proc_tty_unregister_driver(driver); | |
3973 | driver->ttys = NULL; | |
3974 | driver->termios = driver->termios_locked = NULL; | |
3975 | kfree(p); | |
3976 | cdev_del(&driver->cdev); | |
3977 | return 0; | |
3978 | } | |
1da177e4 LT |
3979 | EXPORT_SYMBOL(tty_unregister_driver); |
3980 | ||
24ec839c PZ |
3981 | dev_t tty_devnum(struct tty_struct *tty) |
3982 | { | |
3983 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
3984 | } | |
3985 | EXPORT_SYMBOL(tty_devnum); | |
3986 | ||
3987 | void proc_clear_tty(struct task_struct *p) | |
3988 | { | |
3989 | spin_lock_irq(&p->sighand->siglock); | |
3990 | p->signal->tty = NULL; | |
3991 | spin_unlock_irq(&p->sighand->siglock); | |
3992 | } | |
7cac4ce5 | 3993 | EXPORT_SYMBOL(proc_clear_tty); |
24ec839c | 3994 | |
2a65f1d9 | 3995 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
3996 | { |
3997 | if (tty) { | |
d9c1e9a8 EB |
3998 | /* We should not have a session or pgrp to here but.... */ |
3999 | put_pid(tty->session); | |
4000 | put_pid(tty->pgrp); | |
ab521dc0 EB |
4001 | tty->session = get_pid(task_session(tsk)); |
4002 | tty->pgrp = get_pid(task_pgrp(tsk)); | |
24ec839c | 4003 | } |
2a65f1d9 | 4004 | put_pid(tsk->signal->tty_old_pgrp); |
24ec839c | 4005 | tsk->signal->tty = tty; |
ab521dc0 | 4006 | tsk->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
4007 | } |
4008 | ||
98a27ba4 | 4009 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
4010 | { |
4011 | spin_lock_irq(&tsk->sighand->siglock); | |
2a65f1d9 | 4012 | __proc_set_tty(tsk, tty); |
24ec839c PZ |
4013 | spin_unlock_irq(&tsk->sighand->siglock); |
4014 | } | |
4015 | ||
4016 | struct tty_struct *get_current_tty(void) | |
4017 | { | |
4018 | struct tty_struct *tty; | |
4019 | WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); | |
4020 | tty = current->signal->tty; | |
4021 | /* | |
4022 | * session->tty can be changed/cleared from under us, make sure we | |
4023 | * issue the load. The obtained pointer, when not NULL, is valid as | |
4024 | * long as we hold tty_mutex. | |
4025 | */ | |
4026 | barrier(); | |
4027 | return tty; | |
4028 | } | |
a311f743 | 4029 | EXPORT_SYMBOL_GPL(get_current_tty); |
1da177e4 LT |
4030 | |
4031 | /* | |
4032 | * Initialize the console device. This is called *early*, so | |
4033 | * we can't necessarily depend on lots of kernel help here. | |
4034 | * Just do some early initializations, and do the complex setup | |
4035 | * later. | |
4036 | */ | |
4037 | void __init console_init(void) | |
4038 | { | |
4039 | initcall_t *call; | |
4040 | ||
4041 | /* Setup the default TTY line discipline. */ | |
4042 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); | |
4043 | ||
4044 | /* | |
37bdfb07 | 4045 | * set up the console device so that later boot sequences can |
1da177e4 LT |
4046 | * inform about problems etc.. |
4047 | */ | |
1da177e4 LT |
4048 | call = __con_initcall_start; |
4049 | while (call < __con_initcall_end) { | |
4050 | (*call)(); | |
4051 | call++; | |
4052 | } | |
4053 | } | |
4054 | ||
1da177e4 LT |
4055 | static int __init tty_class_init(void) |
4056 | { | |
7fe845d1 | 4057 | tty_class = class_create(THIS_MODULE, "tty"); |
1da177e4 LT |
4058 | if (IS_ERR(tty_class)) |
4059 | return PTR_ERR(tty_class); | |
4060 | return 0; | |
4061 | } | |
4062 | ||
4063 | postcore_initcall(tty_class_init); | |
4064 | ||
4065 | /* 3/2004 jmc: why do these devices exist? */ | |
4066 | ||
4067 | static struct cdev tty_cdev, console_cdev; | |
4068 | #ifdef CONFIG_UNIX98_PTYS | |
4069 | static struct cdev ptmx_cdev; | |
4070 | #endif | |
4071 | #ifdef CONFIG_VT | |
4072 | static struct cdev vc0_cdev; | |
4073 | #endif | |
4074 | ||
4075 | /* | |
4076 | * Ok, now we can initialize the rest of the tty devices and can count | |
4077 | * on memory allocations, interrupts etc.. | |
4078 | */ | |
4079 | static int __init tty_init(void) | |
4080 | { | |
4081 | cdev_init(&tty_cdev, &tty_fops); | |
4082 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
4083 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
4084 | panic("Couldn't register /dev/tty driver\n"); | |
01107d34 | 4085 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty"); |
1da177e4 LT |
4086 | |
4087 | cdev_init(&console_cdev, &console_fops); | |
4088 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
4089 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
4090 | panic("Couldn't register /dev/console driver\n"); | |
01107d34 | 4091 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console"); |
1da177e4 LT |
4092 | |
4093 | #ifdef CONFIG_UNIX98_PTYS | |
4094 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
4095 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
4096 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
4097 | panic("Couldn't register /dev/ptmx driver\n"); | |
01107d34 | 4098 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); |
1da177e4 LT |
4099 | #endif |
4100 | ||
4101 | #ifdef CONFIG_VT | |
4102 | cdev_init(&vc0_cdev, &console_fops); | |
4103 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || | |
4104 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) | |
4105 | panic("Couldn't register /dev/tty0 driver\n"); | |
01107d34 | 4106 | device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); |
1da177e4 LT |
4107 | |
4108 | vty_init(); | |
4109 | #endif | |
4110 | return 0; | |
4111 | } | |
4112 | module_init(tty_init); |