Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/drivers/char/tty_io.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles | |
9 | * or rs-channels. It also implements echoing, cooked mode etc. | |
10 | * | |
11 | * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. | |
12 | * | |
13 | * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the | |
14 | * tty_struct and tty_queue structures. Previously there was an array | |
15 | * of 256 tty_struct's which was statically allocated, and the | |
16 | * tty_queue structures were allocated at boot time. Both are now | |
17 | * dynamically allocated only when the tty is open. | |
18 | * | |
19 | * Also restructured routines so that there is more of a separation | |
20 | * between the high-level tty routines (tty_io.c and tty_ioctl.c) and | |
21 | * the low-level tty routines (serial.c, pty.c, console.c). This | |
22 | * makes for cleaner and more compact code. -TYT, 9/17/92 | |
23 | * | |
24 | * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines | |
25 | * which can be dynamically activated and de-activated by the line | |
26 | * discipline handling modules (like SLIP). | |
27 | * | |
28 | * NOTE: pay no attention to the line discipline code (yet); its | |
29 | * interface is still subject to change in this version... | |
30 | * -- TYT, 1/31/92 | |
31 | * | |
32 | * Added functionality to the OPOST tty handling. No delays, but all | |
33 | * other bits should be there. | |
34 | * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. | |
35 | * | |
36 | * Rewrote canonical mode and added more termios flags. | |
37 | * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 | |
38 | * | |
39 | * Reorganized FASYNC support so mouse code can share it. | |
40 | * -- ctm@ardi.com, 9Sep95 | |
41 | * | |
42 | * New TIOCLINUX variants added. | |
43 | * -- mj@k332.feld.cvut.cz, 19-Nov-95 | |
44 | * | |
45 | * Restrict vt switching via ioctl() | |
46 | * -- grif@cs.ucr.edu, 5-Dec-95 | |
47 | * | |
48 | * Move console and virtual terminal code to more appropriate files, | |
49 | * implement CONFIG_VT and generalize console device interface. | |
50 | * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 | |
51 | * | |
52 | * Rewrote init_dev and release_dev to eliminate races. | |
53 | * -- Bill Hawes <whawes@star.net>, June 97 | |
54 | * | |
55 | * Added devfs support. | |
56 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 | |
57 | * | |
58 | * Added support for a Unix98-style ptmx device. | |
59 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 | |
60 | * | |
61 | * Reduced memory usage for older ARM systems | |
62 | * -- Russell King <rmk@arm.linux.org.uk> | |
63 | * | |
64 | * Move do_SAK() into process context. Less stack use in devfs functions. | |
65 | * alloc_tty_struct() always uses kmalloc() -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 | |
66 | */ | |
67 | ||
1da177e4 LT |
68 | #include <linux/types.h> |
69 | #include <linux/major.h> | |
70 | #include <linux/errno.h> | |
71 | #include <linux/signal.h> | |
72 | #include <linux/fcntl.h> | |
73 | #include <linux/sched.h> | |
74 | #include <linux/interrupt.h> | |
75 | #include <linux/tty.h> | |
76 | #include <linux/tty_driver.h> | |
77 | #include <linux/tty_flip.h> | |
78 | #include <linux/devpts_fs.h> | |
79 | #include <linux/file.h> | |
80 | #include <linux/console.h> | |
81 | #include <linux/timer.h> | |
82 | #include <linux/ctype.h> | |
83 | #include <linux/kd.h> | |
84 | #include <linux/mm.h> | |
85 | #include <linux/string.h> | |
86 | #include <linux/slab.h> | |
87 | #include <linux/poll.h> | |
88 | #include <linux/proc_fs.h> | |
89 | #include <linux/init.h> | |
90 | #include <linux/module.h> | |
91 | #include <linux/smp_lock.h> | |
92 | #include <linux/device.h> | |
93 | #include <linux/idr.h> | |
94 | #include <linux/wait.h> | |
95 | #include <linux/bitops.h> | |
b20f3ae5 | 96 | #include <linux/delay.h> |
1da177e4 LT |
97 | |
98 | #include <asm/uaccess.h> | |
99 | #include <asm/system.h> | |
100 | ||
101 | #include <linux/kbd_kern.h> | |
102 | #include <linux/vt_kern.h> | |
103 | #include <linux/selection.h> | |
1da177e4 LT |
104 | |
105 | #include <linux/kmod.h> | |
106 | ||
107 | #undef TTY_DEBUG_HANGUP | |
108 | ||
109 | #define TTY_PARANOIA_CHECK 1 | |
110 | #define CHECK_TTY_COUNT 1 | |
111 | ||
edc6afc5 | 112 | struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ |
1da177e4 LT |
113 | .c_iflag = ICRNL | IXON, |
114 | .c_oflag = OPOST | ONLCR, | |
115 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, | |
116 | .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | | |
117 | ECHOCTL | ECHOKE | IEXTEN, | |
edc6afc5 AC |
118 | .c_cc = INIT_C_CC, |
119 | .c_ispeed = 38400, | |
120 | .c_ospeed = 38400 | |
1da177e4 LT |
121 | }; |
122 | ||
123 | EXPORT_SYMBOL(tty_std_termios); | |
124 | ||
125 | /* This list gets poked at by procfs and various bits of boot up code. This | |
126 | could do with some rationalisation such as pulling the tty proc function | |
127 | into this file */ | |
128 | ||
129 | LIST_HEAD(tty_drivers); /* linked list of tty drivers */ | |
130 | ||
24ec839c | 131 | /* Mutex to protect creating and releasing a tty. This is shared with |
1da177e4 | 132 | vt.c for deeply disgusting hack reasons */ |
70522e12 | 133 | DEFINE_MUTEX(tty_mutex); |
de2a84f2 | 134 | EXPORT_SYMBOL(tty_mutex); |
1da177e4 LT |
135 | |
136 | #ifdef CONFIG_UNIX98_PTYS | |
137 | extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ | |
138 | extern int pty_limit; /* Config limit on Unix98 ptys */ | |
139 | static DEFINE_IDR(allocated_ptys); | |
140 | static DECLARE_MUTEX(allocated_ptys_lock); | |
141 | static int ptmx_open(struct inode *, struct file *); | |
142 | #endif | |
143 | ||
1da177e4 LT |
144 | static void initialize_tty_struct(struct tty_struct *tty); |
145 | ||
146 | static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); | |
147 | static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); | |
148 | ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); | |
149 | static unsigned int tty_poll(struct file *, poll_table *); | |
150 | static int tty_open(struct inode *, struct file *); | |
151 | static int tty_release(struct inode *, struct file *); | |
152 | int tty_ioctl(struct inode * inode, struct file * file, | |
153 | unsigned int cmd, unsigned long arg); | |
e10cc1df PF |
154 | #ifdef CONFIG_COMPAT |
155 | static long tty_compat_ioctl(struct file * file, unsigned int cmd, | |
156 | unsigned long arg); | |
157 | #else | |
158 | #define tty_compat_ioctl NULL | |
159 | #endif | |
1da177e4 | 160 | static int tty_fasync(int fd, struct file * filp, int on); |
d5698c28 | 161 | static void release_tty(struct tty_struct *tty, int idx); |
2a65f1d9 | 162 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
98a27ba4 | 163 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
1da177e4 | 164 | |
af9b897e AC |
165 | /** |
166 | * alloc_tty_struct - allocate a tty object | |
167 | * | |
168 | * Return a new empty tty structure. The data fields have not | |
169 | * been initialized in any way but has been zeroed | |
170 | * | |
171 | * Locking: none | |
af9b897e | 172 | */ |
1da177e4 LT |
173 | |
174 | static struct tty_struct *alloc_tty_struct(void) | |
175 | { | |
1266b1e1 | 176 | return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); |
1da177e4 LT |
177 | } |
178 | ||
33f0f88f AC |
179 | static void tty_buffer_free_all(struct tty_struct *); |
180 | ||
af9b897e AC |
181 | /** |
182 | * free_tty_struct - free a disused tty | |
183 | * @tty: tty struct to free | |
184 | * | |
185 | * Free the write buffers, tty queue and tty memory itself. | |
186 | * | |
187 | * Locking: none. Must be called after tty is definitely unused | |
188 | */ | |
189 | ||
1da177e4 LT |
190 | static inline void free_tty_struct(struct tty_struct *tty) |
191 | { | |
192 | kfree(tty->write_buf); | |
33f0f88f | 193 | tty_buffer_free_all(tty); |
1da177e4 LT |
194 | kfree(tty); |
195 | } | |
196 | ||
197 | #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) | |
198 | ||
af9b897e AC |
199 | /** |
200 | * tty_name - return tty naming | |
201 | * @tty: tty structure | |
202 | * @buf: buffer for output | |
203 | * | |
204 | * Convert a tty structure into a name. The name reflects the kernel | |
205 | * naming policy and if udev is in use may not reflect user space | |
206 | * | |
207 | * Locking: none | |
208 | */ | |
209 | ||
1da177e4 LT |
210 | char *tty_name(struct tty_struct *tty, char *buf) |
211 | { | |
212 | if (!tty) /* Hmm. NULL pointer. That's fun. */ | |
213 | strcpy(buf, "NULL tty"); | |
214 | else | |
215 | strcpy(buf, tty->name); | |
216 | return buf; | |
217 | } | |
218 | ||
219 | EXPORT_SYMBOL(tty_name); | |
220 | ||
d769a669 | 221 | int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, |
1da177e4 LT |
222 | const char *routine) |
223 | { | |
224 | #ifdef TTY_PARANOIA_CHECK | |
225 | if (!tty) { | |
226 | printk(KERN_WARNING | |
227 | "null TTY for (%d:%d) in %s\n", | |
228 | imajor(inode), iminor(inode), routine); | |
229 | return 1; | |
230 | } | |
231 | if (tty->magic != TTY_MAGIC) { | |
232 | printk(KERN_WARNING | |
233 | "bad magic number for tty struct (%d:%d) in %s\n", | |
234 | imajor(inode), iminor(inode), routine); | |
235 | return 1; | |
236 | } | |
237 | #endif | |
238 | return 0; | |
239 | } | |
240 | ||
241 | static int check_tty_count(struct tty_struct *tty, const char *routine) | |
242 | { | |
243 | #ifdef CHECK_TTY_COUNT | |
244 | struct list_head *p; | |
245 | int count = 0; | |
246 | ||
247 | file_list_lock(); | |
248 | list_for_each(p, &tty->tty_files) { | |
249 | count++; | |
250 | } | |
251 | file_list_unlock(); | |
252 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
253 | tty->driver->subtype == PTY_TYPE_SLAVE && | |
254 | tty->link && tty->link->count) | |
255 | count++; | |
256 | if (tty->count != count) { | |
257 | printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " | |
258 | "!= #fd's(%d) in %s\n", | |
259 | tty->name, tty->count, count, routine); | |
260 | return count; | |
24ec839c | 261 | } |
1da177e4 LT |
262 | #endif |
263 | return 0; | |
264 | } | |
265 | ||
33f0f88f AC |
266 | /* |
267 | * Tty buffer allocation management | |
268 | */ | |
269 | ||
af9b897e AC |
270 | /** |
271 | * tty_buffer_free_all - free buffers used by a tty | |
272 | * @tty: tty to free from | |
273 | * | |
274 | * Remove all the buffers pending on a tty whether queued with data | |
275 | * or in the free ring. Must be called when the tty is no longer in use | |
276 | * | |
277 | * Locking: none | |
278 | */ | |
279 | ||
33f0f88f AC |
280 | static void tty_buffer_free_all(struct tty_struct *tty) |
281 | { | |
282 | struct tty_buffer *thead; | |
283 | while((thead = tty->buf.head) != NULL) { | |
284 | tty->buf.head = thead->next; | |
285 | kfree(thead); | |
286 | } | |
287 | while((thead = tty->buf.free) != NULL) { | |
288 | tty->buf.free = thead->next; | |
289 | kfree(thead); | |
290 | } | |
291 | tty->buf.tail = NULL; | |
01da5fd8 | 292 | tty->buf.memory_used = 0; |
33f0f88f AC |
293 | } |
294 | ||
01da5fd8 AC |
295 | /** |
296 | * tty_buffer_init - prepare a tty buffer structure | |
297 | * @tty: tty to initialise | |
298 | * | |
299 | * Set up the initial state of the buffer management for a tty device. | |
300 | * Must be called before the other tty buffer functions are used. | |
301 | * | |
302 | * Locking: none | |
303 | */ | |
304 | ||
33f0f88f AC |
305 | static void tty_buffer_init(struct tty_struct *tty) |
306 | { | |
808249ce | 307 | spin_lock_init(&tty->buf.lock); |
33f0f88f AC |
308 | tty->buf.head = NULL; |
309 | tty->buf.tail = NULL; | |
310 | tty->buf.free = NULL; | |
01da5fd8 | 311 | tty->buf.memory_used = 0; |
33f0f88f AC |
312 | } |
313 | ||
01da5fd8 AC |
314 | /** |
315 | * tty_buffer_alloc - allocate a tty buffer | |
316 | * @tty: tty device | |
317 | * @size: desired size (characters) | |
318 | * | |
319 | * Allocate a new tty buffer to hold the desired number of characters. | |
320 | * Return NULL if out of memory or the allocation would exceed the | |
321 | * per device queue | |
322 | * | |
323 | * Locking: Caller must hold tty->buf.lock | |
324 | */ | |
325 | ||
326 | static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) | |
33f0f88f | 327 | { |
01da5fd8 AC |
328 | struct tty_buffer *p; |
329 | ||
330 | if (tty->buf.memory_used + size > 65536) | |
331 | return NULL; | |
332 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); | |
33f0f88f AC |
333 | if(p == NULL) |
334 | return NULL; | |
335 | p->used = 0; | |
336 | p->size = size; | |
337 | p->next = NULL; | |
8977d929 PF |
338 | p->commit = 0; |
339 | p->read = 0; | |
33f0f88f AC |
340 | p->char_buf_ptr = (char *)(p->data); |
341 | p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; | |
01da5fd8 | 342 | tty->buf.memory_used += size; |
33f0f88f AC |
343 | return p; |
344 | } | |
345 | ||
01da5fd8 AC |
346 | /** |
347 | * tty_buffer_free - free a tty buffer | |
348 | * @tty: tty owning the buffer | |
349 | * @b: the buffer to free | |
350 | * | |
351 | * Free a tty buffer, or add it to the free list according to our | |
352 | * internal strategy | |
353 | * | |
354 | * Locking: Caller must hold tty->buf.lock | |
355 | */ | |
33f0f88f AC |
356 | |
357 | static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) | |
358 | { | |
359 | /* Dumb strategy for now - should keep some stats */ | |
01da5fd8 AC |
360 | tty->buf.memory_used -= b->size; |
361 | WARN_ON(tty->buf.memory_used < 0); | |
362 | ||
33f0f88f AC |
363 | if(b->size >= 512) |
364 | kfree(b); | |
365 | else { | |
366 | b->next = tty->buf.free; | |
367 | tty->buf.free = b; | |
368 | } | |
369 | } | |
370 | ||
c5c34d48 PF |
371 | /** |
372 | * tty_buffer_flush - flush full tty buffers | |
373 | * @tty: tty to flush | |
374 | * | |
375 | * flush all the buffers containing receive data | |
376 | * | |
377 | * Locking: none | |
378 | */ | |
379 | ||
380 | static void tty_buffer_flush(struct tty_struct *tty) | |
381 | { | |
382 | struct tty_buffer *thead; | |
383 | unsigned long flags; | |
384 | ||
385 | spin_lock_irqsave(&tty->buf.lock, flags); | |
386 | while((thead = tty->buf.head) != NULL) { | |
387 | tty->buf.head = thead->next; | |
388 | tty_buffer_free(tty, thead); | |
389 | } | |
390 | tty->buf.tail = NULL; | |
391 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
392 | } | |
393 | ||
01da5fd8 AC |
394 | /** |
395 | * tty_buffer_find - find a free tty buffer | |
396 | * @tty: tty owning the buffer | |
397 | * @size: characters wanted | |
398 | * | |
399 | * Locate an existing suitable tty buffer or if we are lacking one then | |
400 | * allocate a new one. We round our buffers off in 256 character chunks | |
401 | * to get better allocation behaviour. | |
402 | * | |
403 | * Locking: Caller must hold tty->buf.lock | |
404 | */ | |
405 | ||
33f0f88f AC |
406 | static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) |
407 | { | |
408 | struct tty_buffer **tbh = &tty->buf.free; | |
409 | while((*tbh) != NULL) { | |
410 | struct tty_buffer *t = *tbh; | |
411 | if(t->size >= size) { | |
412 | *tbh = t->next; | |
413 | t->next = NULL; | |
414 | t->used = 0; | |
8977d929 PF |
415 | t->commit = 0; |
416 | t->read = 0; | |
01da5fd8 | 417 | tty->buf.memory_used += t->size; |
33f0f88f AC |
418 | return t; |
419 | } | |
420 | tbh = &((*tbh)->next); | |
421 | } | |
422 | /* Round the buffer size out */ | |
423 | size = (size + 0xFF) & ~ 0xFF; | |
01da5fd8 | 424 | return tty_buffer_alloc(tty, size); |
33f0f88f AC |
425 | /* Should possibly check if this fails for the largest buffer we |
426 | have queued and recycle that ? */ | |
427 | } | |
428 | ||
01da5fd8 AC |
429 | /** |
430 | * tty_buffer_request_room - grow tty buffer if needed | |
431 | * @tty: tty structure | |
432 | * @size: size desired | |
433 | * | |
434 | * Make at least size bytes of linear space available for the tty | |
435 | * buffer. If we fail return the size we managed to find. | |
436 | * | |
437 | * Locking: Takes tty->buf.lock | |
438 | */ | |
33f0f88f AC |
439 | int tty_buffer_request_room(struct tty_struct *tty, size_t size) |
440 | { | |
808249ce PF |
441 | struct tty_buffer *b, *n; |
442 | int left; | |
443 | unsigned long flags; | |
444 | ||
445 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33f0f88f AC |
446 | |
447 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to | |
448 | remove this conditional if its worth it. This would be invisible | |
449 | to the callers */ | |
33b37a33 | 450 | if ((b = tty->buf.tail) != NULL) |
33f0f88f | 451 | left = b->size - b->used; |
33b37a33 | 452 | else |
808249ce PF |
453 | left = 0; |
454 | ||
455 | if (left < size) { | |
456 | /* This is the slow path - looking for new buffers to use */ | |
457 | if ((n = tty_buffer_find(tty, size)) != NULL) { | |
458 | if (b != NULL) { | |
459 | b->next = n; | |
8977d929 | 460 | b->commit = b->used; |
808249ce PF |
461 | } else |
462 | tty->buf.head = n; | |
463 | tty->buf.tail = n; | |
808249ce PF |
464 | } else |
465 | size = left; | |
466 | } | |
467 | ||
468 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
33f0f88f AC |
469 | return size; |
470 | } | |
33f0f88f AC |
471 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
472 | ||
af9b897e AC |
473 | /** |
474 | * tty_insert_flip_string - Add characters to the tty buffer | |
475 | * @tty: tty structure | |
476 | * @chars: characters | |
477 | * @size: size | |
478 | * | |
479 | * Queue a series of bytes to the tty buffering. All the characters | |
480 | * passed are marked as without error. Returns the number added. | |
481 | * | |
482 | * Locking: Called functions may take tty->buf.lock | |
483 | */ | |
484 | ||
e1a25090 AM |
485 | int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, |
486 | size_t size) | |
33f0f88f AC |
487 | { |
488 | int copied = 0; | |
489 | do { | |
490 | int space = tty_buffer_request_room(tty, size - copied); | |
491 | struct tty_buffer *tb = tty->buf.tail; | |
492 | /* If there is no space then tb may be NULL */ | |
493 | if(unlikely(space == 0)) | |
494 | break; | |
495 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
496 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
497 | tb->used += space; | |
498 | copied += space; | |
499 | chars += space; | |
527063ba AD |
500 | /* There is a small chance that we need to split the data over |
501 | several buffers. If this is the case we must loop */ | |
502 | } while (unlikely(size > copied)); | |
33f0f88f AC |
503 | return copied; |
504 | } | |
ee37df78 | 505 | EXPORT_SYMBOL(tty_insert_flip_string); |
33f0f88f | 506 | |
af9b897e AC |
507 | /** |
508 | * tty_insert_flip_string_flags - Add characters to the tty buffer | |
509 | * @tty: tty structure | |
510 | * @chars: characters | |
511 | * @flags: flag bytes | |
512 | * @size: size | |
513 | * | |
514 | * Queue a series of bytes to the tty buffering. For each character | |
515 | * the flags array indicates the status of the character. Returns the | |
516 | * number added. | |
517 | * | |
518 | * Locking: Called functions may take tty->buf.lock | |
519 | */ | |
520 | ||
e1a25090 AM |
521 | int tty_insert_flip_string_flags(struct tty_struct *tty, |
522 | const unsigned char *chars, const char *flags, size_t size) | |
33f0f88f AC |
523 | { |
524 | int copied = 0; | |
525 | do { | |
526 | int space = tty_buffer_request_room(tty, size - copied); | |
527 | struct tty_buffer *tb = tty->buf.tail; | |
528 | /* If there is no space then tb may be NULL */ | |
529 | if(unlikely(space == 0)) | |
530 | break; | |
531 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
532 | memcpy(tb->flag_buf_ptr + tb->used, flags, space); | |
533 | tb->used += space; | |
534 | copied += space; | |
535 | chars += space; | |
536 | flags += space; | |
527063ba AD |
537 | /* There is a small chance that we need to split the data over |
538 | several buffers. If this is the case we must loop */ | |
539 | } while (unlikely(size > copied)); | |
33f0f88f AC |
540 | return copied; |
541 | } | |
ff4547f4 | 542 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
33f0f88f | 543 | |
af9b897e AC |
544 | /** |
545 | * tty_schedule_flip - push characters to ldisc | |
546 | * @tty: tty to push from | |
547 | * | |
548 | * Takes any pending buffers and transfers their ownership to the | |
549 | * ldisc side of the queue. It then schedules those characters for | |
550 | * processing by the line discipline. | |
551 | * | |
552 | * Locking: Takes tty->buf.lock | |
553 | */ | |
554 | ||
e1a25090 AM |
555 | void tty_schedule_flip(struct tty_struct *tty) |
556 | { | |
557 | unsigned long flags; | |
558 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 559 | if (tty->buf.tail != NULL) |
e1a25090 | 560 | tty->buf.tail->commit = tty->buf.tail->used; |
e1a25090 AM |
561 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
562 | schedule_delayed_work(&tty->buf.work, 1); | |
563 | } | |
564 | EXPORT_SYMBOL(tty_schedule_flip); | |
33f0f88f | 565 | |
af9b897e AC |
566 | /** |
567 | * tty_prepare_flip_string - make room for characters | |
568 | * @tty: tty | |
569 | * @chars: return pointer for character write area | |
570 | * @size: desired size | |
571 | * | |
33f0f88f AC |
572 | * Prepare a block of space in the buffer for data. Returns the length |
573 | * available and buffer pointer to the space which is now allocated and | |
574 | * accounted for as ready for normal characters. This is used for drivers | |
575 | * that need their own block copy routines into the buffer. There is no | |
576 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
577 | * |
578 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
579 | */ |
580 | ||
581 | int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size) | |
582 | { | |
583 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
584 | if (likely(space)) { |
585 | struct tty_buffer *tb = tty->buf.tail; | |
586 | *chars = tb->char_buf_ptr + tb->used; | |
587 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
588 | tb->used += space; | |
589 | } | |
33f0f88f AC |
590 | return space; |
591 | } | |
592 | ||
593 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); | |
594 | ||
af9b897e AC |
595 | /** |
596 | * tty_prepare_flip_string_flags - make room for characters | |
597 | * @tty: tty | |
598 | * @chars: return pointer for character write area | |
599 | * @flags: return pointer for status flag write area | |
600 | * @size: desired size | |
601 | * | |
33f0f88f AC |
602 | * Prepare a block of space in the buffer for data. Returns the length |
603 | * available and buffer pointer to the space which is now allocated and | |
604 | * accounted for as ready for characters. This is used for drivers | |
605 | * that need their own block copy routines into the buffer. There is no | |
606 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
607 | * |
608 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
609 | */ |
610 | ||
611 | int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size) | |
612 | { | |
613 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
614 | if (likely(space)) { |
615 | struct tty_buffer *tb = tty->buf.tail; | |
616 | *chars = tb->char_buf_ptr + tb->used; | |
617 | *flags = tb->flag_buf_ptr + tb->used; | |
618 | tb->used += space; | |
619 | } | |
33f0f88f AC |
620 | return space; |
621 | } | |
622 | ||
623 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); | |
624 | ||
625 | ||
626 | ||
af9b897e AC |
627 | /** |
628 | * tty_set_termios_ldisc - set ldisc field | |
629 | * @tty: tty structure | |
630 | * @num: line discipline number | |
631 | * | |
1da177e4 LT |
632 | * This is probably overkill for real world processors but |
633 | * they are not on hot paths so a little discipline won't do | |
634 | * any harm. | |
af9b897e | 635 | * |
24ec839c | 636 | * Locking: takes termios_mutex |
1da177e4 LT |
637 | */ |
638 | ||
639 | static void tty_set_termios_ldisc(struct tty_struct *tty, int num) | |
640 | { | |
5785c95b | 641 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 642 | tty->termios->c_line = num; |
5785c95b | 643 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
644 | } |
645 | ||
646 | /* | |
647 | * This guards the refcounted line discipline lists. The lock | |
648 | * must be taken with irqs off because there are hangup path | |
649 | * callers who will do ldisc lookups and cannot sleep. | |
650 | */ | |
651 | ||
652 | static DEFINE_SPINLOCK(tty_ldisc_lock); | |
653 | static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); | |
bfb07599 | 654 | static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */ |
1da177e4 | 655 | |
af9b897e AC |
656 | /** |
657 | * tty_register_ldisc - install a line discipline | |
658 | * @disc: ldisc number | |
659 | * @new_ldisc: pointer to the ldisc object | |
660 | * | |
661 | * Installs a new line discipline into the kernel. The discipline | |
662 | * is set up as unreferenced and then made available to the kernel | |
663 | * from this point onwards. | |
664 | * | |
665 | * Locking: | |
666 | * takes tty_ldisc_lock to guard against ldisc races | |
667 | */ | |
668 | ||
1da177e4 LT |
669 | int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) |
670 | { | |
671 | unsigned long flags; | |
672 | int ret = 0; | |
673 | ||
674 | if (disc < N_TTY || disc >= NR_LDISCS) | |
675 | return -EINVAL; | |
676 | ||
677 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
bfb07599 AD |
678 | tty_ldiscs[disc] = *new_ldisc; |
679 | tty_ldiscs[disc].num = disc; | |
680 | tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; | |
681 | tty_ldiscs[disc].refcount = 0; | |
1da177e4 LT |
682 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
683 | ||
684 | return ret; | |
685 | } | |
1da177e4 LT |
686 | EXPORT_SYMBOL(tty_register_ldisc); |
687 | ||
af9b897e AC |
688 | /** |
689 | * tty_unregister_ldisc - unload a line discipline | |
690 | * @disc: ldisc number | |
691 | * @new_ldisc: pointer to the ldisc object | |
692 | * | |
693 | * Remove a line discipline from the kernel providing it is not | |
694 | * currently in use. | |
695 | * | |
696 | * Locking: | |
697 | * takes tty_ldisc_lock to guard against ldisc races | |
698 | */ | |
699 | ||
bfb07599 AD |
700 | int tty_unregister_ldisc(int disc) |
701 | { | |
702 | unsigned long flags; | |
703 | int ret = 0; | |
704 | ||
705 | if (disc < N_TTY || disc >= NR_LDISCS) | |
706 | return -EINVAL; | |
707 | ||
708 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
709 | if (tty_ldiscs[disc].refcount) | |
710 | ret = -EBUSY; | |
711 | else | |
712 | tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; | |
713 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
714 | ||
715 | return ret; | |
716 | } | |
717 | EXPORT_SYMBOL(tty_unregister_ldisc); | |
718 | ||
af9b897e AC |
719 | /** |
720 | * tty_ldisc_get - take a reference to an ldisc | |
721 | * @disc: ldisc number | |
722 | * | |
723 | * Takes a reference to a line discipline. Deals with refcounts and | |
724 | * module locking counts. Returns NULL if the discipline is not available. | |
725 | * Returns a pointer to the discipline and bumps the ref count if it is | |
726 | * available | |
727 | * | |
728 | * Locking: | |
729 | * takes tty_ldisc_lock to guard against ldisc races | |
730 | */ | |
731 | ||
1da177e4 LT |
732 | struct tty_ldisc *tty_ldisc_get(int disc) |
733 | { | |
734 | unsigned long flags; | |
735 | struct tty_ldisc *ld; | |
736 | ||
737 | if (disc < N_TTY || disc >= NR_LDISCS) | |
738 | return NULL; | |
739 | ||
740 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
741 | ||
742 | ld = &tty_ldiscs[disc]; | |
743 | /* Check the entry is defined */ | |
744 | if(ld->flags & LDISC_FLAG_DEFINED) | |
745 | { | |
746 | /* If the module is being unloaded we can't use it */ | |
747 | if (!try_module_get(ld->owner)) | |
748 | ld = NULL; | |
749 | else /* lock it */ | |
750 | ld->refcount++; | |
751 | } | |
752 | else | |
753 | ld = NULL; | |
754 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
755 | return ld; | |
756 | } | |
757 | ||
758 | EXPORT_SYMBOL_GPL(tty_ldisc_get); | |
759 | ||
af9b897e AC |
760 | /** |
761 | * tty_ldisc_put - drop ldisc reference | |
762 | * @disc: ldisc number | |
763 | * | |
764 | * Drop a reference to a line discipline. Manage refcounts and | |
765 | * module usage counts | |
766 | * | |
767 | * Locking: | |
768 | * takes tty_ldisc_lock to guard against ldisc races | |
769 | */ | |
770 | ||
1da177e4 LT |
771 | void tty_ldisc_put(int disc) |
772 | { | |
773 | struct tty_ldisc *ld; | |
774 | unsigned long flags; | |
775 | ||
56ee4827 | 776 | BUG_ON(disc < N_TTY || disc >= NR_LDISCS); |
1da177e4 LT |
777 | |
778 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
779 | ld = &tty_ldiscs[disc]; | |
56ee4827 ES |
780 | BUG_ON(ld->refcount == 0); |
781 | ld->refcount--; | |
1da177e4 LT |
782 | module_put(ld->owner); |
783 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
784 | } | |
785 | ||
786 | EXPORT_SYMBOL_GPL(tty_ldisc_put); | |
787 | ||
af9b897e AC |
788 | /** |
789 | * tty_ldisc_assign - set ldisc on a tty | |
790 | * @tty: tty to assign | |
791 | * @ld: line discipline | |
792 | * | |
793 | * Install an instance of a line discipline into a tty structure. The | |
794 | * ldisc must have a reference count above zero to ensure it remains/ | |
795 | * The tty instance refcount starts at zero. | |
796 | * | |
797 | * Locking: | |
798 | * Caller must hold references | |
799 | */ | |
800 | ||
1da177e4 LT |
801 | static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) |
802 | { | |
803 | tty->ldisc = *ld; | |
804 | tty->ldisc.refcount = 0; | |
805 | } | |
806 | ||
807 | /** | |
808 | * tty_ldisc_try - internal helper | |
809 | * @tty: the tty | |
810 | * | |
811 | * Make a single attempt to grab and bump the refcount on | |
812 | * the tty ldisc. Return 0 on failure or 1 on success. This is | |
813 | * used to implement both the waiting and non waiting versions | |
814 | * of tty_ldisc_ref | |
af9b897e AC |
815 | * |
816 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
817 | */ |
818 | ||
819 | static int tty_ldisc_try(struct tty_struct *tty) | |
820 | { | |
821 | unsigned long flags; | |
822 | struct tty_ldisc *ld; | |
823 | int ret = 0; | |
824 | ||
825 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
826 | ld = &tty->ldisc; | |
827 | if(test_bit(TTY_LDISC, &tty->flags)) | |
828 | { | |
829 | ld->refcount++; | |
830 | ret = 1; | |
831 | } | |
832 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
833 | return ret; | |
834 | } | |
835 | ||
836 | /** | |
837 | * tty_ldisc_ref_wait - wait for the tty ldisc | |
838 | * @tty: tty device | |
839 | * | |
840 | * Dereference the line discipline for the terminal and take a | |
841 | * reference to it. If the line discipline is in flux then | |
842 | * wait patiently until it changes. | |
843 | * | |
844 | * Note: Must not be called from an IRQ/timer context. The caller | |
845 | * must also be careful not to hold other locks that will deadlock | |
846 | * against a discipline change, such as an existing ldisc reference | |
847 | * (which we check for) | |
af9b897e AC |
848 | * |
849 | * Locking: call functions take tty_ldisc_lock | |
1da177e4 LT |
850 | */ |
851 | ||
852 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) | |
853 | { | |
854 | /* wait_event is a macro */ | |
855 | wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); | |
856 | if(tty->ldisc.refcount == 0) | |
857 | printk(KERN_ERR "tty_ldisc_ref_wait\n"); | |
858 | return &tty->ldisc; | |
859 | } | |
860 | ||
861 | EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); | |
862 | ||
863 | /** | |
864 | * tty_ldisc_ref - get the tty ldisc | |
865 | * @tty: tty device | |
866 | * | |
867 | * Dereference the line discipline for the terminal and take a | |
868 | * reference to it. If the line discipline is in flux then | |
869 | * return NULL. Can be called from IRQ and timer functions. | |
af9b897e AC |
870 | * |
871 | * Locking: called functions take tty_ldisc_lock | |
1da177e4 LT |
872 | */ |
873 | ||
874 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) | |
875 | { | |
876 | if(tty_ldisc_try(tty)) | |
877 | return &tty->ldisc; | |
878 | return NULL; | |
879 | } | |
880 | ||
881 | EXPORT_SYMBOL_GPL(tty_ldisc_ref); | |
882 | ||
883 | /** | |
884 | * tty_ldisc_deref - free a tty ldisc reference | |
885 | * @ld: reference to free up | |
886 | * | |
887 | * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May | |
888 | * be called in IRQ context. | |
af9b897e AC |
889 | * |
890 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
891 | */ |
892 | ||
893 | void tty_ldisc_deref(struct tty_ldisc *ld) | |
894 | { | |
895 | unsigned long flags; | |
896 | ||
56ee4827 | 897 | BUG_ON(ld == NULL); |
1da177e4 LT |
898 | |
899 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
900 | if(ld->refcount == 0) | |
901 | printk(KERN_ERR "tty_ldisc_deref: no references.\n"); | |
902 | else | |
903 | ld->refcount--; | |
904 | if(ld->refcount == 0) | |
905 | wake_up(&tty_ldisc_wait); | |
906 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
907 | } | |
908 | ||
909 | EXPORT_SYMBOL_GPL(tty_ldisc_deref); | |
910 | ||
911 | /** | |
912 | * tty_ldisc_enable - allow ldisc use | |
913 | * @tty: terminal to activate ldisc on | |
914 | * | |
915 | * Set the TTY_LDISC flag when the line discipline can be called | |
916 | * again. Do neccessary wakeups for existing sleepers. | |
917 | * | |
918 | * Note: nobody should set this bit except via this function. Clearing | |
919 | * directly is allowed. | |
920 | */ | |
921 | ||
922 | static void tty_ldisc_enable(struct tty_struct *tty) | |
923 | { | |
924 | set_bit(TTY_LDISC, &tty->flags); | |
925 | wake_up(&tty_ldisc_wait); | |
926 | } | |
927 | ||
928 | /** | |
929 | * tty_set_ldisc - set line discipline | |
930 | * @tty: the terminal to set | |
931 | * @ldisc: the line discipline | |
932 | * | |
933 | * Set the discipline of a tty line. Must be called from a process | |
934 | * context. | |
af9b897e AC |
935 | * |
936 | * Locking: takes tty_ldisc_lock. | |
24ec839c | 937 | * called functions take termios_mutex |
1da177e4 LT |
938 | */ |
939 | ||
940 | static int tty_set_ldisc(struct tty_struct *tty, int ldisc) | |
941 | { | |
ff55fe20 JB |
942 | int retval = 0; |
943 | struct tty_ldisc o_ldisc; | |
1da177e4 LT |
944 | char buf[64]; |
945 | int work; | |
946 | unsigned long flags; | |
947 | struct tty_ldisc *ld; | |
ff55fe20 | 948 | struct tty_struct *o_tty; |
1da177e4 LT |
949 | |
950 | if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) | |
951 | return -EINVAL; | |
952 | ||
953 | restart: | |
954 | ||
1da177e4 LT |
955 | ld = tty_ldisc_get(ldisc); |
956 | /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ | |
957 | /* Cyrus Durgin <cider@speakeasy.org> */ | |
958 | if (ld == NULL) { | |
959 | request_module("tty-ldisc-%d", ldisc); | |
960 | ld = tty_ldisc_get(ldisc); | |
961 | } | |
962 | if (ld == NULL) | |
963 | return -EINVAL; | |
964 | ||
33f0f88f AC |
965 | /* |
966 | * Problem: What do we do if this blocks ? | |
967 | */ | |
968 | ||
1da177e4 LT |
969 | tty_wait_until_sent(tty, 0); |
970 | ||
ff55fe20 JB |
971 | if (tty->ldisc.num == ldisc) { |
972 | tty_ldisc_put(ldisc); | |
973 | return 0; | |
974 | } | |
975 | ||
ae030e43 PF |
976 | /* |
977 | * No more input please, we are switching. The new ldisc | |
978 | * will update this value in the ldisc open function | |
979 | */ | |
980 | ||
981 | tty->receive_room = 0; | |
982 | ||
ff55fe20 JB |
983 | o_ldisc = tty->ldisc; |
984 | o_tty = tty->link; | |
985 | ||
1da177e4 LT |
986 | /* |
987 | * Make sure we don't change while someone holds a | |
988 | * reference to the line discipline. The TTY_LDISC bit | |
989 | * prevents anyone taking a reference once it is clear. | |
990 | * We need the lock to avoid racing reference takers. | |
991 | */ | |
ff55fe20 | 992 | |
1da177e4 | 993 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
ff55fe20 JB |
994 | if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { |
995 | if(tty->ldisc.refcount) { | |
996 | /* Free the new ldisc we grabbed. Must drop the lock | |
997 | first. */ | |
998 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
999 | tty_ldisc_put(ldisc); | |
1000 | /* | |
1001 | * There are several reasons we may be busy, including | |
1002 | * random momentary I/O traffic. We must therefore | |
1003 | * retry. We could distinguish between blocking ops | |
1004 | * and retries if we made tty_ldisc_wait() smarter. That | |
1005 | * is up for discussion. | |
1006 | */ | |
1007 | if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) | |
1008 | return -ERESTARTSYS; | |
1009 | goto restart; | |
1010 | } | |
1011 | if(o_tty && o_tty->ldisc.refcount) { | |
1012 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
1013 | tty_ldisc_put(ldisc); | |
1014 | if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) | |
1015 | return -ERESTARTSYS; | |
1016 | goto restart; | |
1017 | } | |
1018 | } | |
1019 | ||
1020 | /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */ | |
1021 | ||
1022 | if (!test_bit(TTY_LDISC, &tty->flags)) { | |
1da177e4 LT |
1023 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
1024 | tty_ldisc_put(ldisc); | |
ff55fe20 JB |
1025 | ld = tty_ldisc_ref_wait(tty); |
1026 | tty_ldisc_deref(ld); | |
1da177e4 LT |
1027 | goto restart; |
1028 | } | |
ff55fe20 JB |
1029 | |
1030 | clear_bit(TTY_LDISC, &tty->flags); | |
817d6d3b | 1031 | if (o_tty) |
ff55fe20 | 1032 | clear_bit(TTY_LDISC, &o_tty->flags); |
1da177e4 | 1033 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
ff55fe20 | 1034 | |
1da177e4 LT |
1035 | /* |
1036 | * From this point on we know nobody has an ldisc | |
1037 | * usage reference, nor can they obtain one until | |
1038 | * we say so later on. | |
1039 | */ | |
ff55fe20 | 1040 | |
33f0f88f | 1041 | work = cancel_delayed_work(&tty->buf.work); |
1da177e4 | 1042 | /* |
33f0f88f | 1043 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 LT |
1044 | */ |
1045 | ||
1046 | flush_scheduled_work(); | |
1047 | /* Shutdown the current discipline. */ | |
1048 | if (tty->ldisc.close) | |
1049 | (tty->ldisc.close)(tty); | |
1050 | ||
1051 | /* Now set up the new line discipline. */ | |
1052 | tty_ldisc_assign(tty, ld); | |
1053 | tty_set_termios_ldisc(tty, ldisc); | |
1054 | if (tty->ldisc.open) | |
1055 | retval = (tty->ldisc.open)(tty); | |
1056 | if (retval < 0) { | |
1057 | tty_ldisc_put(ldisc); | |
1058 | /* There is an outstanding reference here so this is safe */ | |
1059 | tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); | |
1060 | tty_set_termios_ldisc(tty, tty->ldisc.num); | |
1061 | if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { | |
1062 | tty_ldisc_put(o_ldisc.num); | |
1063 | /* This driver is always present */ | |
1064 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
1065 | tty_set_termios_ldisc(tty, N_TTY); | |
1066 | if (tty->ldisc.open) { | |
1067 | int r = tty->ldisc.open(tty); | |
1068 | ||
1069 | if (r < 0) | |
1070 | panic("Couldn't open N_TTY ldisc for " | |
1071 | "%s --- error %d.", | |
1072 | tty_name(tty, buf), r); | |
1073 | } | |
1074 | } | |
1075 | } | |
1076 | /* At this point we hold a reference to the new ldisc and a | |
1077 | a reference to the old ldisc. If we ended up flipping back | |
1078 | to the existing ldisc we have two references to it */ | |
1079 | ||
1080 | if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) | |
1081 | tty->driver->set_ldisc(tty); | |
1082 | ||
1083 | tty_ldisc_put(o_ldisc.num); | |
1084 | ||
1085 | /* | |
1086 | * Allow ldisc referencing to occur as soon as the driver | |
1087 | * ldisc callback completes. | |
1088 | */ | |
1089 | ||
1090 | tty_ldisc_enable(tty); | |
ff55fe20 JB |
1091 | if (o_tty) |
1092 | tty_ldisc_enable(o_tty); | |
1da177e4 LT |
1093 | |
1094 | /* Restart it in case no characters kick it off. Safe if | |
1095 | already running */ | |
ff55fe20 | 1096 | if (work) |
33f0f88f | 1097 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
1098 | return retval; |
1099 | } | |
1100 | ||
af9b897e AC |
1101 | /** |
1102 | * get_tty_driver - find device of a tty | |
1103 | * @dev_t: device identifier | |
1104 | * @index: returns the index of the tty | |
1105 | * | |
1106 | * This routine returns a tty driver structure, given a device number | |
1107 | * and also passes back the index number. | |
1108 | * | |
1109 | * Locking: caller must hold tty_mutex | |
1da177e4 | 1110 | */ |
af9b897e | 1111 | |
1da177e4 LT |
1112 | static struct tty_driver *get_tty_driver(dev_t device, int *index) |
1113 | { | |
1114 | struct tty_driver *p; | |
1115 | ||
1116 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1117 | dev_t base = MKDEV(p->major, p->minor_start); | |
1118 | if (device < base || device >= base + p->num) | |
1119 | continue; | |
1120 | *index = device - base; | |
1121 | return p; | |
1122 | } | |
1123 | return NULL; | |
1124 | } | |
1125 | ||
af9b897e AC |
1126 | /** |
1127 | * tty_check_change - check for POSIX terminal changes | |
1128 | * @tty: tty to check | |
1129 | * | |
1130 | * If we try to write to, or set the state of, a terminal and we're | |
1131 | * not in the foreground, send a SIGTTOU. If the signal is blocked or | |
1132 | * ignored, go ahead and perform the operation. (POSIX 7.2) | |
1133 | * | |
1134 | * Locking: none | |
1da177e4 | 1135 | */ |
af9b897e | 1136 | |
1da177e4 LT |
1137 | int tty_check_change(struct tty_struct * tty) |
1138 | { | |
1139 | if (current->signal->tty != tty) | |
1140 | return 0; | |
ab521dc0 EB |
1141 | if (!tty->pgrp) { |
1142 | printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n"); | |
1da177e4 LT |
1143 | return 0; |
1144 | } | |
ab521dc0 | 1145 | if (task_pgrp(current) == tty->pgrp) |
1da177e4 LT |
1146 | return 0; |
1147 | if (is_ignored(SIGTTOU)) | |
1148 | return 0; | |
3e7cd6c4 | 1149 | if (is_current_pgrp_orphaned()) |
1da177e4 | 1150 | return -EIO; |
040b6362 ON |
1151 | kill_pgrp(task_pgrp(current), SIGTTOU, 1); |
1152 | set_thread_flag(TIF_SIGPENDING); | |
1da177e4 LT |
1153 | return -ERESTARTSYS; |
1154 | } | |
1155 | ||
1156 | EXPORT_SYMBOL(tty_check_change); | |
1157 | ||
1158 | static ssize_t hung_up_tty_read(struct file * file, char __user * buf, | |
1159 | size_t count, loff_t *ppos) | |
1160 | { | |
1161 | return 0; | |
1162 | } | |
1163 | ||
1164 | static ssize_t hung_up_tty_write(struct file * file, const char __user * buf, | |
1165 | size_t count, loff_t *ppos) | |
1166 | { | |
1167 | return -EIO; | |
1168 | } | |
1169 | ||
1170 | /* No kernel lock held - none needed ;) */ | |
1171 | static unsigned int hung_up_tty_poll(struct file * filp, poll_table * wait) | |
1172 | { | |
1173 | return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; | |
1174 | } | |
1175 | ||
38ad2ed0 PF |
1176 | static int hung_up_tty_ioctl(struct inode * inode, struct file * file, |
1177 | unsigned int cmd, unsigned long arg) | |
1178 | { | |
1179 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1180 | } | |
1181 | ||
1182 | static long hung_up_tty_compat_ioctl(struct file * file, | |
1183 | unsigned int cmd, unsigned long arg) | |
1da177e4 LT |
1184 | { |
1185 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1186 | } | |
1187 | ||
62322d25 | 1188 | static const struct file_operations tty_fops = { |
1da177e4 LT |
1189 | .llseek = no_llseek, |
1190 | .read = tty_read, | |
1191 | .write = tty_write, | |
1192 | .poll = tty_poll, | |
1193 | .ioctl = tty_ioctl, | |
e10cc1df | 1194 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1195 | .open = tty_open, |
1196 | .release = tty_release, | |
1197 | .fasync = tty_fasync, | |
1198 | }; | |
1199 | ||
1200 | #ifdef CONFIG_UNIX98_PTYS | |
62322d25 | 1201 | static const struct file_operations ptmx_fops = { |
1da177e4 LT |
1202 | .llseek = no_llseek, |
1203 | .read = tty_read, | |
1204 | .write = tty_write, | |
1205 | .poll = tty_poll, | |
1206 | .ioctl = tty_ioctl, | |
e10cc1df | 1207 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1208 | .open = ptmx_open, |
1209 | .release = tty_release, | |
1210 | .fasync = tty_fasync, | |
1211 | }; | |
1212 | #endif | |
1213 | ||
62322d25 | 1214 | static const struct file_operations console_fops = { |
1da177e4 LT |
1215 | .llseek = no_llseek, |
1216 | .read = tty_read, | |
1217 | .write = redirected_tty_write, | |
1218 | .poll = tty_poll, | |
1219 | .ioctl = tty_ioctl, | |
e10cc1df | 1220 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1221 | .open = tty_open, |
1222 | .release = tty_release, | |
1223 | .fasync = tty_fasync, | |
1224 | }; | |
1225 | ||
62322d25 | 1226 | static const struct file_operations hung_up_tty_fops = { |
1da177e4 LT |
1227 | .llseek = no_llseek, |
1228 | .read = hung_up_tty_read, | |
1229 | .write = hung_up_tty_write, | |
1230 | .poll = hung_up_tty_poll, | |
38ad2ed0 PF |
1231 | .ioctl = hung_up_tty_ioctl, |
1232 | .compat_ioctl = hung_up_tty_compat_ioctl, | |
1da177e4 LT |
1233 | .release = tty_release, |
1234 | }; | |
1235 | ||
1236 | static DEFINE_SPINLOCK(redirect_lock); | |
1237 | static struct file *redirect; | |
1238 | ||
1239 | /** | |
1240 | * tty_wakeup - request more data | |
1241 | * @tty: terminal | |
1242 | * | |
1243 | * Internal and external helper for wakeups of tty. This function | |
1244 | * informs the line discipline if present that the driver is ready | |
1245 | * to receive more output data. | |
1246 | */ | |
1247 | ||
1248 | void tty_wakeup(struct tty_struct *tty) | |
1249 | { | |
1250 | struct tty_ldisc *ld; | |
1251 | ||
1252 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { | |
1253 | ld = tty_ldisc_ref(tty); | |
1254 | if(ld) { | |
1255 | if(ld->write_wakeup) | |
1256 | ld->write_wakeup(tty); | |
1257 | tty_ldisc_deref(ld); | |
1258 | } | |
1259 | } | |
1260 | wake_up_interruptible(&tty->write_wait); | |
1261 | } | |
1262 | ||
1263 | EXPORT_SYMBOL_GPL(tty_wakeup); | |
1264 | ||
1265 | /** | |
1266 | * tty_ldisc_flush - flush line discipline queue | |
1267 | * @tty: tty | |
1268 | * | |
1269 | * Flush the line discipline queue (if any) for this tty. If there | |
1270 | * is no line discipline active this is a no-op. | |
1271 | */ | |
1272 | ||
1273 | void tty_ldisc_flush(struct tty_struct *tty) | |
1274 | { | |
1275 | struct tty_ldisc *ld = tty_ldisc_ref(tty); | |
1276 | if(ld) { | |
1277 | if(ld->flush_buffer) | |
1278 | ld->flush_buffer(tty); | |
1279 | tty_ldisc_deref(ld); | |
1280 | } | |
c5c34d48 | 1281 | tty_buffer_flush(tty); |
1da177e4 LT |
1282 | } |
1283 | ||
1284 | EXPORT_SYMBOL_GPL(tty_ldisc_flush); | |
edc6afc5 AC |
1285 | |
1286 | /** | |
1287 | * tty_reset_termios - reset terminal state | |
1288 | * @tty: tty to reset | |
1289 | * | |
1290 | * Restore a terminal to the driver default state | |
1291 | */ | |
1292 | ||
1293 | static void tty_reset_termios(struct tty_struct *tty) | |
1294 | { | |
1295 | mutex_lock(&tty->termios_mutex); | |
1296 | *tty->termios = tty->driver->init_termios; | |
1297 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
1298 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1299 | mutex_unlock(&tty->termios_mutex); | |
1300 | } | |
1da177e4 | 1301 | |
af9b897e AC |
1302 | /** |
1303 | * do_tty_hangup - actual handler for hangup events | |
65f27f38 | 1304 | * @work: tty device |
af9b897e AC |
1305 | * |
1306 | * This can be called by the "eventd" kernel thread. That is process | |
1307 | * synchronous but doesn't hold any locks, so we need to make sure we | |
1308 | * have the appropriate locks for what we're doing. | |
1309 | * | |
1310 | * The hangup event clears any pending redirections onto the hung up | |
1311 | * device. It ensures future writes will error and it does the needed | |
1312 | * line discipline hangup and signal delivery. The tty object itself | |
1313 | * remains intact. | |
1314 | * | |
1315 | * Locking: | |
1316 | * BKL | |
24ec839c PZ |
1317 | * redirect lock for undoing redirection |
1318 | * file list lock for manipulating list of ttys | |
1319 | * tty_ldisc_lock from called functions | |
1320 | * termios_mutex resetting termios data | |
1321 | * tasklist_lock to walk task list for hangup event | |
1322 | * ->siglock to protect ->signal/->sighand | |
1da177e4 | 1323 | */ |
65f27f38 | 1324 | static void do_tty_hangup(struct work_struct *work) |
1da177e4 | 1325 | { |
65f27f38 DH |
1326 | struct tty_struct *tty = |
1327 | container_of(work, struct tty_struct, hangup_work); | |
1da177e4 LT |
1328 | struct file * cons_filp = NULL; |
1329 | struct file *filp, *f = NULL; | |
1330 | struct task_struct *p; | |
1331 | struct tty_ldisc *ld; | |
1332 | int closecount = 0, n; | |
1333 | ||
1334 | if (!tty) | |
1335 | return; | |
1336 | ||
1337 | /* inuse_filps is protected by the single kernel lock */ | |
1338 | lock_kernel(); | |
1339 | ||
1340 | spin_lock(&redirect_lock); | |
1341 | if (redirect && redirect->private_data == tty) { | |
1342 | f = redirect; | |
1343 | redirect = NULL; | |
1344 | } | |
1345 | spin_unlock(&redirect_lock); | |
1346 | ||
1347 | check_tty_count(tty, "do_tty_hangup"); | |
1348 | file_list_lock(); | |
1349 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ | |
2f512016 | 1350 | list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { |
1da177e4 LT |
1351 | if (filp->f_op->write == redirected_tty_write) |
1352 | cons_filp = filp; | |
1353 | if (filp->f_op->write != tty_write) | |
1354 | continue; | |
1355 | closecount++; | |
1356 | tty_fasync(-1, filp, 0); /* can't block */ | |
1357 | filp->f_op = &hung_up_tty_fops; | |
1358 | } | |
1359 | file_list_unlock(); | |
1360 | ||
1361 | /* FIXME! What are the locking issues here? This may me overdoing things.. | |
1362 | * this question is especially important now that we've removed the irqlock. */ | |
1363 | ||
1364 | ld = tty_ldisc_ref(tty); | |
1365 | if(ld != NULL) /* We may have no line discipline at this point */ | |
1366 | { | |
1367 | if (ld->flush_buffer) | |
1368 | ld->flush_buffer(tty); | |
1369 | if (tty->driver->flush_buffer) | |
1370 | tty->driver->flush_buffer(tty); | |
1371 | if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && | |
1372 | ld->write_wakeup) | |
1373 | ld->write_wakeup(tty); | |
1374 | if (ld->hangup) | |
1375 | ld->hangup(tty); | |
1376 | } | |
1377 | ||
1378 | /* FIXME: Once we trust the LDISC code better we can wait here for | |
1379 | ldisc completion and fix the driver call race */ | |
1380 | ||
1381 | wake_up_interruptible(&tty->write_wait); | |
1382 | wake_up_interruptible(&tty->read_wait); | |
1383 | ||
1384 | /* | |
1385 | * Shutdown the current line discipline, and reset it to | |
1386 | * N_TTY. | |
1387 | */ | |
1388 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
edc6afc5 | 1389 | tty_reset_termios(tty); |
1da177e4 LT |
1390 | |
1391 | /* Defer ldisc switch */ | |
1392 | /* tty_deferred_ldisc_switch(N_TTY); | |
1393 | ||
1394 | This should get done automatically when the port closes and | |
1395 | tty_release is called */ | |
1396 | ||
1397 | read_lock(&tasklist_lock); | |
ab521dc0 EB |
1398 | if (tty->session) { |
1399 | do_each_pid_task(tty->session, PIDTYPE_SID, p) { | |
24ec839c | 1400 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
1401 | if (p->signal->tty == tty) |
1402 | p->signal->tty = NULL; | |
24ec839c PZ |
1403 | if (!p->signal->leader) { |
1404 | spin_unlock_irq(&p->sighand->siglock); | |
1da177e4 | 1405 | continue; |
24ec839c PZ |
1406 | } |
1407 | __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); | |
1408 | __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); | |
ab521dc0 EB |
1409 | put_pid(p->signal->tty_old_pgrp); /* A noop */ |
1410 | if (tty->pgrp) | |
1411 | p->signal->tty_old_pgrp = get_pid(tty->pgrp); | |
24ec839c | 1412 | spin_unlock_irq(&p->sighand->siglock); |
ab521dc0 | 1413 | } while_each_pid_task(tty->session, PIDTYPE_SID, p); |
1da177e4 LT |
1414 | } |
1415 | read_unlock(&tasklist_lock); | |
1416 | ||
1417 | tty->flags = 0; | |
d9c1e9a8 EB |
1418 | put_pid(tty->session); |
1419 | put_pid(tty->pgrp); | |
ab521dc0 EB |
1420 | tty->session = NULL; |
1421 | tty->pgrp = NULL; | |
1da177e4 LT |
1422 | tty->ctrl_status = 0; |
1423 | /* | |
1424 | * If one of the devices matches a console pointer, we | |
1425 | * cannot just call hangup() because that will cause | |
1426 | * tty->count and state->count to go out of sync. | |
1427 | * So we just call close() the right number of times. | |
1428 | */ | |
1429 | if (cons_filp) { | |
1430 | if (tty->driver->close) | |
1431 | for (n = 0; n < closecount; n++) | |
1432 | tty->driver->close(tty, cons_filp); | |
1433 | } else if (tty->driver->hangup) | |
1434 | (tty->driver->hangup)(tty); | |
1435 | ||
1436 | /* We don't want to have driver/ldisc interactions beyond | |
1437 | the ones we did here. The driver layer expects no | |
1438 | calls after ->hangup() from the ldisc side. However we | |
1439 | can't yet guarantee all that */ | |
1440 | ||
1441 | set_bit(TTY_HUPPED, &tty->flags); | |
1442 | if (ld) { | |
1443 | tty_ldisc_enable(tty); | |
1444 | tty_ldisc_deref(ld); | |
1445 | } | |
1446 | unlock_kernel(); | |
1447 | if (f) | |
1448 | fput(f); | |
1449 | } | |
1450 | ||
af9b897e AC |
1451 | /** |
1452 | * tty_hangup - trigger a hangup event | |
1453 | * @tty: tty to hangup | |
1454 | * | |
1455 | * A carrier loss (virtual or otherwise) has occurred on this like | |
1456 | * schedule a hangup sequence to run after this event. | |
1457 | */ | |
1458 | ||
1da177e4 LT |
1459 | void tty_hangup(struct tty_struct * tty) |
1460 | { | |
1461 | #ifdef TTY_DEBUG_HANGUP | |
1462 | char buf[64]; | |
1463 | ||
1464 | printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); | |
1465 | #endif | |
1466 | schedule_work(&tty->hangup_work); | |
1467 | } | |
1468 | ||
1469 | EXPORT_SYMBOL(tty_hangup); | |
1470 | ||
af9b897e AC |
1471 | /** |
1472 | * tty_vhangup - process vhangup | |
1473 | * @tty: tty to hangup | |
1474 | * | |
1475 | * The user has asked via system call for the terminal to be hung up. | |
1476 | * We do this synchronously so that when the syscall returns the process | |
1477 | * is complete. That guarantee is neccessary for security reasons. | |
1478 | */ | |
1479 | ||
1da177e4 LT |
1480 | void tty_vhangup(struct tty_struct * tty) |
1481 | { | |
1482 | #ifdef TTY_DEBUG_HANGUP | |
1483 | char buf[64]; | |
1484 | ||
1485 | printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); | |
1486 | #endif | |
65f27f38 | 1487 | do_tty_hangup(&tty->hangup_work); |
1da177e4 LT |
1488 | } |
1489 | EXPORT_SYMBOL(tty_vhangup); | |
1490 | ||
af9b897e AC |
1491 | /** |
1492 | * tty_hung_up_p - was tty hung up | |
1493 | * @filp: file pointer of tty | |
1494 | * | |
1495 | * Return true if the tty has been subject to a vhangup or a carrier | |
1496 | * loss | |
1497 | */ | |
1498 | ||
1da177e4 LT |
1499 | int tty_hung_up_p(struct file * filp) |
1500 | { | |
1501 | return (filp->f_op == &hung_up_tty_fops); | |
1502 | } | |
1503 | ||
1504 | EXPORT_SYMBOL(tty_hung_up_p); | |
1505 | ||
ab521dc0 | 1506 | static void session_clear_tty(struct pid *session) |
24ec839c PZ |
1507 | { |
1508 | struct task_struct *p; | |
ab521dc0 | 1509 | do_each_pid_task(session, PIDTYPE_SID, p) { |
24ec839c | 1510 | proc_clear_tty(p); |
ab521dc0 | 1511 | } while_each_pid_task(session, PIDTYPE_SID, p); |
24ec839c PZ |
1512 | } |
1513 | ||
af9b897e AC |
1514 | /** |
1515 | * disassociate_ctty - disconnect controlling tty | |
1516 | * @on_exit: true if exiting so need to "hang up" the session | |
1da177e4 | 1517 | * |
af9b897e AC |
1518 | * This function is typically called only by the session leader, when |
1519 | * it wants to disassociate itself from its controlling tty. | |
1520 | * | |
1521 | * It performs the following functions: | |
1da177e4 LT |
1522 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
1523 | * (2) Clears the tty from being controlling the session | |
1524 | * (3) Clears the controlling tty for all processes in the | |
1525 | * session group. | |
1526 | * | |
af9b897e AC |
1527 | * The argument on_exit is set to 1 if called when a process is |
1528 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. | |
1529 | * | |
24ec839c | 1530 | * Locking: |
af9b897e | 1531 | * BKL is taken for hysterical raisins |
24ec839c PZ |
1532 | * tty_mutex is taken to protect tty |
1533 | * ->siglock is taken to protect ->signal/->sighand | |
1534 | * tasklist_lock is taken to walk process list for sessions | |
1535 | * ->siglock is taken to protect ->signal/->sighand | |
1da177e4 | 1536 | */ |
af9b897e | 1537 | |
1da177e4 LT |
1538 | void disassociate_ctty(int on_exit) |
1539 | { | |
1540 | struct tty_struct *tty; | |
ab521dc0 | 1541 | struct pid *tty_pgrp = NULL; |
1da177e4 LT |
1542 | |
1543 | lock_kernel(); | |
1544 | ||
70522e12 | 1545 | mutex_lock(&tty_mutex); |
24ec839c | 1546 | tty = get_current_tty(); |
1da177e4 | 1547 | if (tty) { |
ab521dc0 | 1548 | tty_pgrp = get_pid(tty->pgrp); |
70522e12 | 1549 | mutex_unlock(&tty_mutex); |
24ec839c | 1550 | /* XXX: here we race, there is nothing protecting tty */ |
1da177e4 LT |
1551 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
1552 | tty_vhangup(tty); | |
680a9671 | 1553 | } else if (on_exit) { |
ab521dc0 | 1554 | struct pid *old_pgrp; |
680a9671 EB |
1555 | spin_lock_irq(¤t->sighand->siglock); |
1556 | old_pgrp = current->signal->tty_old_pgrp; | |
ab521dc0 | 1557 | current->signal->tty_old_pgrp = NULL; |
680a9671 | 1558 | spin_unlock_irq(¤t->sighand->siglock); |
24ec839c | 1559 | if (old_pgrp) { |
ab521dc0 EB |
1560 | kill_pgrp(old_pgrp, SIGHUP, on_exit); |
1561 | kill_pgrp(old_pgrp, SIGCONT, on_exit); | |
1562 | put_pid(old_pgrp); | |
1da177e4 | 1563 | } |
70522e12 | 1564 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
1565 | unlock_kernel(); |
1566 | return; | |
1567 | } | |
ab521dc0 EB |
1568 | if (tty_pgrp) { |
1569 | kill_pgrp(tty_pgrp, SIGHUP, on_exit); | |
1da177e4 | 1570 | if (!on_exit) |
ab521dc0 EB |
1571 | kill_pgrp(tty_pgrp, SIGCONT, on_exit); |
1572 | put_pid(tty_pgrp); | |
1da177e4 LT |
1573 | } |
1574 | ||
24ec839c | 1575 | spin_lock_irq(¤t->sighand->siglock); |
2a65f1d9 | 1576 | put_pid(current->signal->tty_old_pgrp); |
23cac8de | 1577 | current->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
1578 | spin_unlock_irq(¤t->sighand->siglock); |
1579 | ||
1580 | mutex_lock(&tty_mutex); | |
1581 | /* It is possible that do_tty_hangup has free'd this tty */ | |
1582 | tty = get_current_tty(); | |
1583 | if (tty) { | |
ab521dc0 EB |
1584 | put_pid(tty->session); |
1585 | put_pid(tty->pgrp); | |
1586 | tty->session = NULL; | |
1587 | tty->pgrp = NULL; | |
24ec839c PZ |
1588 | } else { |
1589 | #ifdef TTY_DEBUG_HANGUP | |
1590 | printk(KERN_DEBUG "error attempted to write to tty [0x%p]" | |
1591 | " = NULL", tty); | |
1592 | #endif | |
1593 | } | |
1594 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
1595 | |
1596 | /* Now clear signal->tty under the lock */ | |
1597 | read_lock(&tasklist_lock); | |
ab521dc0 | 1598 | session_clear_tty(task_session(current)); |
1da177e4 | 1599 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1600 | unlock_kernel(); |
1601 | } | |
1602 | ||
98a27ba4 EB |
1603 | /** |
1604 | * | |
1605 | * no_tty - Ensure the current process does not have a controlling tty | |
1606 | */ | |
1607 | void no_tty(void) | |
1608 | { | |
1609 | struct task_struct *tsk = current; | |
1610 | if (tsk->signal->leader) | |
1611 | disassociate_ctty(0); | |
1612 | proc_clear_tty(tsk); | |
1613 | } | |
1614 | ||
af9b897e AC |
1615 | |
1616 | /** | |
beb7dd86 | 1617 | * stop_tty - propagate flow control |
af9b897e AC |
1618 | * @tty: tty to stop |
1619 | * | |
1620 | * Perform flow control to the driver. For PTY/TTY pairs we | |
beb7dd86 | 1621 | * must also propagate the TIOCKPKT status. May be called |
af9b897e AC |
1622 | * on an already stopped device and will not re-call the driver |
1623 | * method. | |
1624 | * | |
1625 | * This functionality is used by both the line disciplines for | |
1626 | * halting incoming flow and by the driver. It may therefore be | |
1627 | * called from any context, may be under the tty atomic_write_lock | |
1628 | * but not always. | |
1629 | * | |
1630 | * Locking: | |
1631 | * Broken. Relies on BKL which is unsafe here. | |
1632 | */ | |
1633 | ||
1da177e4 LT |
1634 | void stop_tty(struct tty_struct *tty) |
1635 | { | |
1636 | if (tty->stopped) | |
1637 | return; | |
1638 | tty->stopped = 1; | |
1639 | if (tty->link && tty->link->packet) { | |
1640 | tty->ctrl_status &= ~TIOCPKT_START; | |
1641 | tty->ctrl_status |= TIOCPKT_STOP; | |
1642 | wake_up_interruptible(&tty->link->read_wait); | |
1643 | } | |
1644 | if (tty->driver->stop) | |
1645 | (tty->driver->stop)(tty); | |
1646 | } | |
1647 | ||
1648 | EXPORT_SYMBOL(stop_tty); | |
1649 | ||
af9b897e | 1650 | /** |
beb7dd86 | 1651 | * start_tty - propagate flow control |
af9b897e AC |
1652 | * @tty: tty to start |
1653 | * | |
1654 | * Start a tty that has been stopped if at all possible. Perform | |
beb7dd86 | 1655 | * any neccessary wakeups and propagate the TIOCPKT status. If this |
af9b897e AC |
1656 | * is the tty was previous stopped and is being started then the |
1657 | * driver start method is invoked and the line discipline woken. | |
1658 | * | |
1659 | * Locking: | |
1660 | * Broken. Relies on BKL which is unsafe here. | |
1661 | */ | |
1662 | ||
1da177e4 LT |
1663 | void start_tty(struct tty_struct *tty) |
1664 | { | |
1665 | if (!tty->stopped || tty->flow_stopped) | |
1666 | return; | |
1667 | tty->stopped = 0; | |
1668 | if (tty->link && tty->link->packet) { | |
1669 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
1670 | tty->ctrl_status |= TIOCPKT_START; | |
1671 | wake_up_interruptible(&tty->link->read_wait); | |
1672 | } | |
1673 | if (tty->driver->start) | |
1674 | (tty->driver->start)(tty); | |
1675 | ||
1676 | /* If we have a running line discipline it may need kicking */ | |
1677 | tty_wakeup(tty); | |
1da177e4 LT |
1678 | } |
1679 | ||
1680 | EXPORT_SYMBOL(start_tty); | |
1681 | ||
af9b897e AC |
1682 | /** |
1683 | * tty_read - read method for tty device files | |
1684 | * @file: pointer to tty file | |
1685 | * @buf: user buffer | |
1686 | * @count: size of user buffer | |
1687 | * @ppos: unused | |
1688 | * | |
1689 | * Perform the read system call function on this terminal device. Checks | |
1690 | * for hung up devices before calling the line discipline method. | |
1691 | * | |
1692 | * Locking: | |
1693 | * Locks the line discipline internally while needed | |
1694 | * For historical reasons the line discipline read method is | |
1695 | * invoked under the BKL. This will go away in time so do not rely on it | |
1696 | * in new code. Multiple read calls may be outstanding in parallel. | |
1697 | */ | |
1698 | ||
1da177e4 LT |
1699 | static ssize_t tty_read(struct file * file, char __user * buf, size_t count, |
1700 | loff_t *ppos) | |
1701 | { | |
1702 | int i; | |
1703 | struct tty_struct * tty; | |
1704 | struct inode *inode; | |
1705 | struct tty_ldisc *ld; | |
1706 | ||
1707 | tty = (struct tty_struct *)file->private_data; | |
a7113a96 | 1708 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1709 | if (tty_paranoia_check(tty, inode, "tty_read")) |
1710 | return -EIO; | |
1711 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1712 | return -EIO; | |
1713 | ||
1714 | /* We want to wait for the line discipline to sort out in this | |
1715 | situation */ | |
1716 | ld = tty_ldisc_ref_wait(tty); | |
1717 | lock_kernel(); | |
1718 | if (ld->read) | |
1719 | i = (ld->read)(tty,file,buf,count); | |
1720 | else | |
1721 | i = -EIO; | |
1722 | tty_ldisc_deref(ld); | |
1723 | unlock_kernel(); | |
1724 | if (i > 0) | |
1725 | inode->i_atime = current_fs_time(inode->i_sb); | |
1726 | return i; | |
1727 | } | |
1728 | ||
9c1729db AC |
1729 | void tty_write_unlock(struct tty_struct *tty) |
1730 | { | |
1731 | mutex_unlock(&tty->atomic_write_lock); | |
1732 | wake_up_interruptible(&tty->write_wait); | |
1733 | } | |
1734 | ||
1735 | int tty_write_lock(struct tty_struct *tty, int ndelay) | |
1736 | { | |
1737 | if (!mutex_trylock(&tty->atomic_write_lock)) { | |
1738 | if (ndelay) | |
1739 | return -EAGAIN; | |
1740 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) | |
1741 | return -ERESTARTSYS; | |
1742 | } | |
1743 | return 0; | |
1744 | } | |
1745 | ||
1da177e4 LT |
1746 | /* |
1747 | * Split writes up in sane blocksizes to avoid | |
1748 | * denial-of-service type attacks | |
1749 | */ | |
1750 | static inline ssize_t do_tty_write( | |
1751 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
1752 | struct tty_struct *tty, | |
1753 | struct file *file, | |
1754 | const char __user *buf, | |
1755 | size_t count) | |
1756 | { | |
9c1729db | 1757 | ssize_t ret, written = 0; |
1da177e4 LT |
1758 | unsigned int chunk; |
1759 | ||
9c1729db AC |
1760 | ret = tty_write_lock(tty, file->f_flags & O_NDELAY); |
1761 | if (ret < 0) | |
1762 | return ret; | |
1da177e4 LT |
1763 | |
1764 | /* | |
1765 | * We chunk up writes into a temporary buffer. This | |
1766 | * simplifies low-level drivers immensely, since they | |
1767 | * don't have locking issues and user mode accesses. | |
1768 | * | |
1769 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
1770 | * big chunk-size.. | |
1771 | * | |
1772 | * The default chunk-size is 2kB, because the NTTY | |
1773 | * layer has problems with bigger chunks. It will | |
1774 | * claim to be able to handle more characters than | |
1775 | * it actually does. | |
af9b897e AC |
1776 | * |
1777 | * FIXME: This can probably go away now except that 64K chunks | |
1778 | * are too likely to fail unless switched to vmalloc... | |
1da177e4 LT |
1779 | */ |
1780 | chunk = 2048; | |
1781 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
1782 | chunk = 65536; | |
1783 | if (count < chunk) | |
1784 | chunk = count; | |
1785 | ||
70522e12 | 1786 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
1da177e4 LT |
1787 | if (tty->write_cnt < chunk) { |
1788 | unsigned char *buf; | |
1789 | ||
1790 | if (chunk < 1024) | |
1791 | chunk = 1024; | |
1792 | ||
1793 | buf = kmalloc(chunk, GFP_KERNEL); | |
1794 | if (!buf) { | |
9c1729db AC |
1795 | ret = -ENOMEM; |
1796 | goto out; | |
1da177e4 LT |
1797 | } |
1798 | kfree(tty->write_buf); | |
1799 | tty->write_cnt = chunk; | |
1800 | tty->write_buf = buf; | |
1801 | } | |
1802 | ||
1803 | /* Do the write .. */ | |
1804 | for (;;) { | |
1805 | size_t size = count; | |
1806 | if (size > chunk) | |
1807 | size = chunk; | |
1808 | ret = -EFAULT; | |
1809 | if (copy_from_user(tty->write_buf, buf, size)) | |
1810 | break; | |
1811 | lock_kernel(); | |
1812 | ret = write(tty, file, tty->write_buf, size); | |
1813 | unlock_kernel(); | |
1814 | if (ret <= 0) | |
1815 | break; | |
1816 | written += ret; | |
1817 | buf += ret; | |
1818 | count -= ret; | |
1819 | if (!count) | |
1820 | break; | |
1821 | ret = -ERESTARTSYS; | |
1822 | if (signal_pending(current)) | |
1823 | break; | |
1824 | cond_resched(); | |
1825 | } | |
1826 | if (written) { | |
a7113a96 | 1827 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1828 | inode->i_mtime = current_fs_time(inode->i_sb); |
1829 | ret = written; | |
1830 | } | |
9c1729db AC |
1831 | out: |
1832 | tty_write_unlock(tty); | |
1da177e4 LT |
1833 | return ret; |
1834 | } | |
1835 | ||
1836 | ||
af9b897e AC |
1837 | /** |
1838 | * tty_write - write method for tty device file | |
1839 | * @file: tty file pointer | |
1840 | * @buf: user data to write | |
1841 | * @count: bytes to write | |
1842 | * @ppos: unused | |
1843 | * | |
1844 | * Write data to a tty device via the line discipline. | |
1845 | * | |
1846 | * Locking: | |
1847 | * Locks the line discipline as required | |
1848 | * Writes to the tty driver are serialized by the atomic_write_lock | |
1849 | * and are then processed in chunks to the device. The line discipline | |
1850 | * write method will not be involked in parallel for each device | |
1851 | * The line discipline write method is called under the big | |
1852 | * kernel lock for historical reasons. New code should not rely on this. | |
1853 | */ | |
1854 | ||
1da177e4 LT |
1855 | static ssize_t tty_write(struct file * file, const char __user * buf, size_t count, |
1856 | loff_t *ppos) | |
1857 | { | |
1858 | struct tty_struct * tty; | |
a7113a96 | 1859 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1860 | ssize_t ret; |
1861 | struct tty_ldisc *ld; | |
1862 | ||
1863 | tty = (struct tty_struct *)file->private_data; | |
1864 | if (tty_paranoia_check(tty, inode, "tty_write")) | |
1865 | return -EIO; | |
1866 | if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1867 | return -EIO; | |
1868 | ||
1869 | ld = tty_ldisc_ref_wait(tty); | |
1870 | if (!ld->write) | |
1871 | ret = -EIO; | |
1872 | else | |
1873 | ret = do_tty_write(ld->write, tty, file, buf, count); | |
1874 | tty_ldisc_deref(ld); | |
1875 | return ret; | |
1876 | } | |
1877 | ||
1878 | ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count, | |
1879 | loff_t *ppos) | |
1880 | { | |
1881 | struct file *p = NULL; | |
1882 | ||
1883 | spin_lock(&redirect_lock); | |
1884 | if (redirect) { | |
1885 | get_file(redirect); | |
1886 | p = redirect; | |
1887 | } | |
1888 | spin_unlock(&redirect_lock); | |
1889 | ||
1890 | if (p) { | |
1891 | ssize_t res; | |
1892 | res = vfs_write(p, buf, count, &p->f_pos); | |
1893 | fput(p); | |
1894 | return res; | |
1895 | } | |
1896 | ||
1897 | return tty_write(file, buf, count, ppos); | |
1898 | } | |
1899 | ||
1900 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
1901 | ||
af9b897e AC |
1902 | /** |
1903 | * pty_line_name - generate name for a pty | |
1904 | * @driver: the tty driver in use | |
1905 | * @index: the minor number | |
1906 | * @p: output buffer of at least 6 bytes | |
1907 | * | |
1908 | * Generate a name from a driver reference and write it to the output | |
1909 | * buffer. | |
1910 | * | |
1911 | * Locking: None | |
1912 | */ | |
1913 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1914 | { |
1915 | int i = index + driver->name_base; | |
1916 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
1917 | sprintf(p, "%s%c%x", | |
1918 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, | |
1919 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1920 | } | |
1921 | ||
af9b897e AC |
1922 | /** |
1923 | * pty_line_name - generate name for a tty | |
1924 | * @driver: the tty driver in use | |
1925 | * @index: the minor number | |
1926 | * @p: output buffer of at least 7 bytes | |
1927 | * | |
1928 | * Generate a name from a driver reference and write it to the output | |
1929 | * buffer. | |
1930 | * | |
1931 | * Locking: None | |
1932 | */ | |
1933 | static void tty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1934 | { |
1935 | sprintf(p, "%s%d", driver->name, index + driver->name_base); | |
1936 | } | |
1937 | ||
af9b897e AC |
1938 | /** |
1939 | * init_dev - initialise a tty device | |
1940 | * @driver: tty driver we are opening a device on | |
1941 | * @idx: device index | |
1942 | * @tty: returned tty structure | |
1943 | * | |
1944 | * Prepare a tty device. This may not be a "new" clean device but | |
1945 | * could also be an active device. The pty drivers require special | |
1946 | * handling because of this. | |
1947 | * | |
1948 | * Locking: | |
1949 | * The function is called under the tty_mutex, which | |
1950 | * protects us from the tty struct or driver itself going away. | |
1951 | * | |
1952 | * On exit the tty device has the line discipline attached and | |
1953 | * a reference count of 1. If a pair was created for pty/tty use | |
1954 | * and the other was a pty master then it too has a reference count of 1. | |
1955 | * | |
1da177e4 | 1956 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
70522e12 IM |
1957 | * failed open. The new code protects the open with a mutex, so it's |
1958 | * really quite straightforward. The mutex locking can probably be | |
1da177e4 LT |
1959 | * relaxed for the (most common) case of reopening a tty. |
1960 | */ | |
af9b897e | 1961 | |
1da177e4 LT |
1962 | static int init_dev(struct tty_driver *driver, int idx, |
1963 | struct tty_struct **ret_tty) | |
1964 | { | |
1965 | struct tty_struct *tty, *o_tty; | |
edc6afc5 AC |
1966 | struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; |
1967 | struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; | |
af9b897e | 1968 | int retval = 0; |
1da177e4 LT |
1969 | |
1970 | /* check whether we're reopening an existing tty */ | |
1971 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
1972 | tty = devpts_get_tty(idx); | |
5a39e8c6 ASRF |
1973 | /* |
1974 | * If we don't have a tty here on a slave open, it's because | |
1975 | * the master already started the close process and there's | |
1976 | * no relation between devpts file and tty anymore. | |
1977 | */ | |
1978 | if (!tty && driver->subtype == PTY_TYPE_SLAVE) { | |
1979 | retval = -EIO; | |
1980 | goto end_init; | |
1981 | } | |
1982 | /* | |
1983 | * It's safe from now on because init_dev() is called with | |
1984 | * tty_mutex held and release_dev() won't change tty->count | |
1985 | * or tty->flags without having to grab tty_mutex | |
1986 | */ | |
1da177e4 LT |
1987 | if (tty && driver->subtype == PTY_TYPE_MASTER) |
1988 | tty = tty->link; | |
1989 | } else { | |
1990 | tty = driver->ttys[idx]; | |
1991 | } | |
1992 | if (tty) goto fast_track; | |
1993 | ||
1994 | /* | |
1995 | * First time open is complex, especially for PTY devices. | |
1996 | * This code guarantees that either everything succeeds and the | |
1997 | * TTY is ready for operation, or else the table slots are vacated | |
1998 | * and the allocated memory released. (Except that the termios | |
1999 | * and locked termios may be retained.) | |
2000 | */ | |
2001 | ||
2002 | if (!try_module_get(driver->owner)) { | |
2003 | retval = -ENODEV; | |
2004 | goto end_init; | |
2005 | } | |
2006 | ||
2007 | o_tty = NULL; | |
2008 | tp = o_tp = NULL; | |
2009 | ltp = o_ltp = NULL; | |
2010 | ||
2011 | tty = alloc_tty_struct(); | |
2012 | if(!tty) | |
2013 | goto fail_no_mem; | |
2014 | initialize_tty_struct(tty); | |
2015 | tty->driver = driver; | |
2016 | tty->index = idx; | |
2017 | tty_line_name(driver, idx, tty->name); | |
2018 | ||
2019 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2020 | tp_loc = &tty->termios; | |
2021 | ltp_loc = &tty->termios_locked; | |
2022 | } else { | |
2023 | tp_loc = &driver->termios[idx]; | |
2024 | ltp_loc = &driver->termios_locked[idx]; | |
2025 | } | |
2026 | ||
2027 | if (!*tp_loc) { | |
edc6afc5 | 2028 | tp = (struct ktermios *) kmalloc(sizeof(struct ktermios), |
1da177e4 LT |
2029 | GFP_KERNEL); |
2030 | if (!tp) | |
2031 | goto free_mem_out; | |
2032 | *tp = driver->init_termios; | |
2033 | } | |
2034 | ||
2035 | if (!*ltp_loc) { | |
506eb99a | 2036 | ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2037 | if (!ltp) |
2038 | goto free_mem_out; | |
1da177e4 LT |
2039 | } |
2040 | ||
2041 | if (driver->type == TTY_DRIVER_TYPE_PTY) { | |
2042 | o_tty = alloc_tty_struct(); | |
2043 | if (!o_tty) | |
2044 | goto free_mem_out; | |
2045 | initialize_tty_struct(o_tty); | |
2046 | o_tty->driver = driver->other; | |
2047 | o_tty->index = idx; | |
2048 | tty_line_name(driver->other, idx, o_tty->name); | |
2049 | ||
2050 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2051 | o_tp_loc = &o_tty->termios; | |
2052 | o_ltp_loc = &o_tty->termios_locked; | |
2053 | } else { | |
2054 | o_tp_loc = &driver->other->termios[idx]; | |
2055 | o_ltp_loc = &driver->other->termios_locked[idx]; | |
2056 | } | |
2057 | ||
2058 | if (!*o_tp_loc) { | |
edc6afc5 AC |
2059 | o_tp = (struct ktermios *) |
2060 | kmalloc(sizeof(struct ktermios), GFP_KERNEL); | |
1da177e4 LT |
2061 | if (!o_tp) |
2062 | goto free_mem_out; | |
2063 | *o_tp = driver->other->init_termios; | |
2064 | } | |
2065 | ||
2066 | if (!*o_ltp_loc) { | |
506eb99a | 2067 | o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2068 | if (!o_ltp) |
2069 | goto free_mem_out; | |
1da177e4 LT |
2070 | } |
2071 | ||
2072 | /* | |
2073 | * Everything allocated ... set up the o_tty structure. | |
2074 | */ | |
2075 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2076 | driver->other->ttys[idx] = o_tty; | |
2077 | } | |
2078 | if (!*o_tp_loc) | |
2079 | *o_tp_loc = o_tp; | |
2080 | if (!*o_ltp_loc) | |
2081 | *o_ltp_loc = o_ltp; | |
2082 | o_tty->termios = *o_tp_loc; | |
2083 | o_tty->termios_locked = *o_ltp_loc; | |
2084 | driver->other->refcount++; | |
2085 | if (driver->subtype == PTY_TYPE_MASTER) | |
2086 | o_tty->count++; | |
2087 | ||
2088 | /* Establish the links in both directions */ | |
2089 | tty->link = o_tty; | |
2090 | o_tty->link = tty; | |
2091 | } | |
2092 | ||
2093 | /* | |
2094 | * All structures have been allocated, so now we install them. | |
d5698c28 | 2095 | * Failures after this point use release_tty to clean up, so |
1da177e4 LT |
2096 | * there's no need to null out the local pointers. |
2097 | */ | |
2098 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2099 | driver->ttys[idx] = tty; | |
2100 | } | |
2101 | ||
2102 | if (!*tp_loc) | |
2103 | *tp_loc = tp; | |
2104 | if (!*ltp_loc) | |
2105 | *ltp_loc = ltp; | |
2106 | tty->termios = *tp_loc; | |
2107 | tty->termios_locked = *ltp_loc; | |
edc6afc5 AC |
2108 | /* Compatibility until drivers always set this */ |
2109 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
2110 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1da177e4 LT |
2111 | driver->refcount++; |
2112 | tty->count++; | |
2113 | ||
2114 | /* | |
2115 | * Structures all installed ... call the ldisc open routines. | |
d5698c28 CH |
2116 | * If we fail here just call release_tty to clean up. No need |
2117 | * to decrement the use counts, as release_tty doesn't care. | |
1da177e4 LT |
2118 | */ |
2119 | ||
2120 | if (tty->ldisc.open) { | |
2121 | retval = (tty->ldisc.open)(tty); | |
2122 | if (retval) | |
2123 | goto release_mem_out; | |
2124 | } | |
2125 | if (o_tty && o_tty->ldisc.open) { | |
2126 | retval = (o_tty->ldisc.open)(o_tty); | |
2127 | if (retval) { | |
2128 | if (tty->ldisc.close) | |
2129 | (tty->ldisc.close)(tty); | |
2130 | goto release_mem_out; | |
2131 | } | |
2132 | tty_ldisc_enable(o_tty); | |
2133 | } | |
2134 | tty_ldisc_enable(tty); | |
2135 | goto success; | |
2136 | ||
2137 | /* | |
2138 | * This fast open can be used if the tty is already open. | |
2139 | * No memory is allocated, and the only failures are from | |
2140 | * attempting to open a closing tty or attempting multiple | |
2141 | * opens on a pty master. | |
2142 | */ | |
2143 | fast_track: | |
2144 | if (test_bit(TTY_CLOSING, &tty->flags)) { | |
2145 | retval = -EIO; | |
2146 | goto end_init; | |
2147 | } | |
2148 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
2149 | driver->subtype == PTY_TYPE_MASTER) { | |
2150 | /* | |
2151 | * special case for PTY masters: only one open permitted, | |
2152 | * and the slave side open count is incremented as well. | |
2153 | */ | |
2154 | if (tty->count) { | |
2155 | retval = -EIO; | |
2156 | goto end_init; | |
2157 | } | |
2158 | tty->link->count++; | |
2159 | } | |
2160 | tty->count++; | |
2161 | tty->driver = driver; /* N.B. why do this every time?? */ | |
2162 | ||
2163 | /* FIXME */ | |
2164 | if(!test_bit(TTY_LDISC, &tty->flags)) | |
2165 | printk(KERN_ERR "init_dev but no ldisc\n"); | |
2166 | success: | |
2167 | *ret_tty = tty; | |
2168 | ||
70522e12 | 2169 | /* All paths come through here to release the mutex */ |
1da177e4 LT |
2170 | end_init: |
2171 | return retval; | |
2172 | ||
2173 | /* Release locally allocated memory ... nothing placed in slots */ | |
2174 | free_mem_out: | |
735d5661 | 2175 | kfree(o_tp); |
1da177e4 LT |
2176 | if (o_tty) |
2177 | free_tty_struct(o_tty); | |
735d5661 JJ |
2178 | kfree(ltp); |
2179 | kfree(tp); | |
1da177e4 LT |
2180 | free_tty_struct(tty); |
2181 | ||
2182 | fail_no_mem: | |
2183 | module_put(driver->owner); | |
2184 | retval = -ENOMEM; | |
2185 | goto end_init; | |
2186 | ||
d5698c28 | 2187 | /* call the tty release_tty routine to clean out this slot */ |
1da177e4 | 2188 | release_mem_out: |
4050914f AM |
2189 | if (printk_ratelimit()) |
2190 | printk(KERN_INFO "init_dev: ldisc open failed, " | |
2191 | "clearing slot %d\n", idx); | |
d5698c28 | 2192 | release_tty(tty, idx); |
1da177e4 LT |
2193 | goto end_init; |
2194 | } | |
2195 | ||
af9b897e | 2196 | /** |
d5698c28 | 2197 | * release_one_tty - release tty structure memory |
af9b897e AC |
2198 | * |
2199 | * Releases memory associated with a tty structure, and clears out the | |
2200 | * driver table slots. This function is called when a device is no longer | |
2201 | * in use. It also gets called when setup of a device fails. | |
2202 | * | |
2203 | * Locking: | |
2204 | * tty_mutex - sometimes only | |
2205 | * takes the file list lock internally when working on the list | |
2206 | * of ttys that the driver keeps. | |
2207 | * FIXME: should we require tty_mutex is held here ?? | |
1da177e4 | 2208 | */ |
d5698c28 | 2209 | static void release_one_tty(struct tty_struct *tty, int idx) |
1da177e4 | 2210 | { |
1da177e4 | 2211 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
d5698c28 | 2212 | struct ktermios *tp; |
1da177e4 LT |
2213 | |
2214 | if (!devpts) | |
2215 | tty->driver->ttys[idx] = NULL; | |
d5698c28 | 2216 | |
1da177e4 LT |
2217 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
2218 | tp = tty->termios; | |
2219 | if (!devpts) | |
2220 | tty->driver->termios[idx] = NULL; | |
2221 | kfree(tp); | |
2222 | ||
2223 | tp = tty->termios_locked; | |
2224 | if (!devpts) | |
2225 | tty->driver->termios_locked[idx] = NULL; | |
2226 | kfree(tp); | |
2227 | } | |
2228 | ||
d5698c28 | 2229 | |
1da177e4 LT |
2230 | tty->magic = 0; |
2231 | tty->driver->refcount--; | |
d5698c28 | 2232 | |
1da177e4 LT |
2233 | file_list_lock(); |
2234 | list_del_init(&tty->tty_files); | |
2235 | file_list_unlock(); | |
d5698c28 | 2236 | |
1da177e4 LT |
2237 | free_tty_struct(tty); |
2238 | } | |
2239 | ||
d5698c28 CH |
2240 | /** |
2241 | * release_tty - release tty structure memory | |
2242 | * | |
2243 | * Release both @tty and a possible linked partner (think pty pair), | |
2244 | * and decrement the refcount of the backing module. | |
2245 | * | |
2246 | * Locking: | |
2247 | * tty_mutex - sometimes only | |
2248 | * takes the file list lock internally when working on the list | |
2249 | * of ttys that the driver keeps. | |
2250 | * FIXME: should we require tty_mutex is held here ?? | |
2251 | */ | |
2252 | static void release_tty(struct tty_struct *tty, int idx) | |
2253 | { | |
2254 | struct tty_driver *driver = tty->driver; | |
2255 | ||
2256 | if (tty->link) | |
2257 | release_one_tty(tty->link, idx); | |
2258 | release_one_tty(tty, idx); | |
2259 | module_put(driver->owner); | |
2260 | } | |
2261 | ||
1da177e4 LT |
2262 | /* |
2263 | * Even releasing the tty structures is a tricky business.. We have | |
2264 | * to be very careful that the structures are all released at the | |
2265 | * same time, as interrupts might otherwise get the wrong pointers. | |
2266 | * | |
2267 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
2268 | * lead to double frees or releasing memory still in use. | |
2269 | */ | |
2270 | static void release_dev(struct file * filp) | |
2271 | { | |
2272 | struct tty_struct *tty, *o_tty; | |
2273 | int pty_master, tty_closing, o_tty_closing, do_sleep; | |
14a6283e | 2274 | int devpts; |
1da177e4 LT |
2275 | int idx; |
2276 | char buf[64]; | |
2277 | unsigned long flags; | |
2278 | ||
2279 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2280 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "release_dev")) |
1da177e4 LT |
2281 | return; |
2282 | ||
2283 | check_tty_count(tty, "release_dev"); | |
2284 | ||
2285 | tty_fasync(-1, filp, 0); | |
2286 | ||
2287 | idx = tty->index; | |
2288 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2289 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2290 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; | |
1da177e4 LT |
2291 | o_tty = tty->link; |
2292 | ||
2293 | #ifdef TTY_PARANOIA_CHECK | |
2294 | if (idx < 0 || idx >= tty->driver->num) { | |
2295 | printk(KERN_DEBUG "release_dev: bad idx when trying to " | |
2296 | "free (%s)\n", tty->name); | |
2297 | return; | |
2298 | } | |
2299 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2300 | if (tty != tty->driver->ttys[idx]) { | |
2301 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " | |
2302 | "for (%s)\n", idx, tty->name); | |
2303 | return; | |
2304 | } | |
2305 | if (tty->termios != tty->driver->termios[idx]) { | |
2306 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " | |
2307 | "for (%s)\n", | |
2308 | idx, tty->name); | |
2309 | return; | |
2310 | } | |
2311 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { | |
2312 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " | |
2313 | "termios_locked for (%s)\n", | |
2314 | idx, tty->name); | |
2315 | return; | |
2316 | } | |
2317 | } | |
2318 | #endif | |
2319 | ||
2320 | #ifdef TTY_DEBUG_HANGUP | |
2321 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", | |
2322 | tty_name(tty, buf), tty->count); | |
2323 | #endif | |
2324 | ||
2325 | #ifdef TTY_PARANOIA_CHECK | |
2326 | if (tty->driver->other && | |
2327 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2328 | if (o_tty != tty->driver->other->ttys[idx]) { | |
2329 | printk(KERN_DEBUG "release_dev: other->table[%d] " | |
2330 | "not o_tty for (%s)\n", | |
2331 | idx, tty->name); | |
2332 | return; | |
2333 | } | |
2334 | if (o_tty->termios != tty->driver->other->termios[idx]) { | |
2335 | printk(KERN_DEBUG "release_dev: other->termios[%d] " | |
2336 | "not o_termios for (%s)\n", | |
2337 | idx, tty->name); | |
2338 | return; | |
2339 | } | |
2340 | if (o_tty->termios_locked != | |
2341 | tty->driver->other->termios_locked[idx]) { | |
2342 | printk(KERN_DEBUG "release_dev: other->termios_locked[" | |
2343 | "%d] not o_termios_locked for (%s)\n", | |
2344 | idx, tty->name); | |
2345 | return; | |
2346 | } | |
2347 | if (o_tty->link != tty) { | |
2348 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); | |
2349 | return; | |
2350 | } | |
2351 | } | |
2352 | #endif | |
2353 | if (tty->driver->close) | |
2354 | tty->driver->close(tty, filp); | |
2355 | ||
2356 | /* | |
2357 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
2358 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
2359 | * wait queues and kick everyone out _before_ actually starting to | |
2360 | * close. This ensures that we won't block while releasing the tty | |
2361 | * structure. | |
2362 | * | |
2363 | * The test for the o_tty closing is necessary, since the master and | |
2364 | * slave sides may close in any order. If the slave side closes out | |
2365 | * first, its count will be one, since the master side holds an open. | |
2366 | * Thus this test wouldn't be triggered at the time the slave closes, | |
2367 | * so we do it now. | |
2368 | * | |
2369 | * Note that it's possible for the tty to be opened again while we're | |
2370 | * flushing out waiters. By recalculating the closing flags before | |
2371 | * each iteration we avoid any problems. | |
2372 | */ | |
2373 | while (1) { | |
2374 | /* Guard against races with tty->count changes elsewhere and | |
2375 | opens on /dev/tty */ | |
2376 | ||
70522e12 | 2377 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2378 | tty_closing = tty->count <= 1; |
2379 | o_tty_closing = o_tty && | |
2380 | (o_tty->count <= (pty_master ? 1 : 0)); | |
1da177e4 LT |
2381 | do_sleep = 0; |
2382 | ||
2383 | if (tty_closing) { | |
2384 | if (waitqueue_active(&tty->read_wait)) { | |
2385 | wake_up(&tty->read_wait); | |
2386 | do_sleep++; | |
2387 | } | |
2388 | if (waitqueue_active(&tty->write_wait)) { | |
2389 | wake_up(&tty->write_wait); | |
2390 | do_sleep++; | |
2391 | } | |
2392 | } | |
2393 | if (o_tty_closing) { | |
2394 | if (waitqueue_active(&o_tty->read_wait)) { | |
2395 | wake_up(&o_tty->read_wait); | |
2396 | do_sleep++; | |
2397 | } | |
2398 | if (waitqueue_active(&o_tty->write_wait)) { | |
2399 | wake_up(&o_tty->write_wait); | |
2400 | do_sleep++; | |
2401 | } | |
2402 | } | |
2403 | if (!do_sleep) | |
2404 | break; | |
2405 | ||
2406 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " | |
2407 | "active!\n", tty_name(tty, buf)); | |
70522e12 | 2408 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2409 | schedule(); |
2410 | } | |
2411 | ||
2412 | /* | |
2413 | * The closing flags are now consistent with the open counts on | |
2414 | * both sides, and we've completed the last operation that could | |
2415 | * block, so it's safe to proceed with closing. | |
2416 | */ | |
1da177e4 LT |
2417 | if (pty_master) { |
2418 | if (--o_tty->count < 0) { | |
2419 | printk(KERN_WARNING "release_dev: bad pty slave count " | |
2420 | "(%d) for %s\n", | |
2421 | o_tty->count, tty_name(o_tty, buf)); | |
2422 | o_tty->count = 0; | |
2423 | } | |
2424 | } | |
2425 | if (--tty->count < 0) { | |
2426 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", | |
2427 | tty->count, tty_name(tty, buf)); | |
2428 | tty->count = 0; | |
2429 | } | |
1da177e4 LT |
2430 | |
2431 | /* | |
2432 | * We've decremented tty->count, so we need to remove this file | |
2433 | * descriptor off the tty->tty_files list; this serves two | |
2434 | * purposes: | |
2435 | * - check_tty_count sees the correct number of file descriptors | |
2436 | * associated with this tty. | |
2437 | * - do_tty_hangup no longer sees this file descriptor as | |
2438 | * something that needs to be handled for hangups. | |
2439 | */ | |
2440 | file_kill(filp); | |
2441 | filp->private_data = NULL; | |
2442 | ||
2443 | /* | |
2444 | * Perform some housekeeping before deciding whether to return. | |
2445 | * | |
2446 | * Set the TTY_CLOSING flag if this was the last open. In the | |
2447 | * case of a pty we may have to wait around for the other side | |
2448 | * to close, and TTY_CLOSING makes sure we can't be reopened. | |
2449 | */ | |
2450 | if(tty_closing) | |
2451 | set_bit(TTY_CLOSING, &tty->flags); | |
2452 | if(o_tty_closing) | |
2453 | set_bit(TTY_CLOSING, &o_tty->flags); | |
2454 | ||
2455 | /* | |
2456 | * If _either_ side is closing, make sure there aren't any | |
2457 | * processes that still think tty or o_tty is their controlling | |
2458 | * tty. | |
2459 | */ | |
2460 | if (tty_closing || o_tty_closing) { | |
1da177e4 | 2461 | read_lock(&tasklist_lock); |
24ec839c | 2462 | session_clear_tty(tty->session); |
1da177e4 | 2463 | if (o_tty) |
24ec839c | 2464 | session_clear_tty(o_tty->session); |
1da177e4 LT |
2465 | read_unlock(&tasklist_lock); |
2466 | } | |
2467 | ||
70522e12 | 2468 | mutex_unlock(&tty_mutex); |
da965822 | 2469 | |
1da177e4 LT |
2470 | /* check whether both sides are closing ... */ |
2471 | if (!tty_closing || (o_tty && !o_tty_closing)) | |
2472 | return; | |
2473 | ||
2474 | #ifdef TTY_DEBUG_HANGUP | |
2475 | printk(KERN_DEBUG "freeing tty structure..."); | |
2476 | #endif | |
2477 | /* | |
2478 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then | |
2479 | * kill any delayed work. As this is the final close it does not | |
2480 | * race with the set_ldisc code path. | |
2481 | */ | |
2482 | clear_bit(TTY_LDISC, &tty->flags); | |
33f0f88f | 2483 | cancel_delayed_work(&tty->buf.work); |
1da177e4 LT |
2484 | |
2485 | /* | |
33f0f88f | 2486 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 LT |
2487 | */ |
2488 | ||
2489 | flush_scheduled_work(); | |
2490 | ||
2491 | /* | |
2492 | * Wait for any short term users (we know they are just driver | |
2493 | * side waiters as the file is closing so user count on the file | |
2494 | * side is zero. | |
2495 | */ | |
2496 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2497 | while(tty->ldisc.refcount) | |
2498 | { | |
2499 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2500 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); | |
2501 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2502 | } | |
2503 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2504 | /* | |
2505 | * Shutdown the current line discipline, and reset it to N_TTY. | |
2506 | * N.B. why reset ldisc when we're releasing the memory?? | |
2507 | * | |
2508 | * FIXME: this MUST get fixed for the new reflocking | |
2509 | */ | |
2510 | if (tty->ldisc.close) | |
2511 | (tty->ldisc.close)(tty); | |
2512 | tty_ldisc_put(tty->ldisc.num); | |
2513 | ||
2514 | /* | |
2515 | * Switch the line discipline back | |
2516 | */ | |
2517 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
2518 | tty_set_termios_ldisc(tty,N_TTY); | |
2519 | if (o_tty) { | |
2520 | /* FIXME: could o_tty be in setldisc here ? */ | |
2521 | clear_bit(TTY_LDISC, &o_tty->flags); | |
2522 | if (o_tty->ldisc.close) | |
2523 | (o_tty->ldisc.close)(o_tty); | |
2524 | tty_ldisc_put(o_tty->ldisc.num); | |
2525 | tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); | |
2526 | tty_set_termios_ldisc(o_tty,N_TTY); | |
2527 | } | |
2528 | /* | |
d5698c28 | 2529 | * The release_tty function takes care of the details of clearing |
1da177e4 LT |
2530 | * the slots and preserving the termios structure. |
2531 | */ | |
d5698c28 | 2532 | release_tty(tty, idx); |
1da177e4 LT |
2533 | |
2534 | #ifdef CONFIG_UNIX98_PTYS | |
2535 | /* Make this pty number available for reallocation */ | |
2536 | if (devpts) { | |
2537 | down(&allocated_ptys_lock); | |
2538 | idr_remove(&allocated_ptys, idx); | |
2539 | up(&allocated_ptys_lock); | |
2540 | } | |
2541 | #endif | |
2542 | ||
2543 | } | |
2544 | ||
af9b897e AC |
2545 | /** |
2546 | * tty_open - open a tty device | |
2547 | * @inode: inode of device file | |
2548 | * @filp: file pointer to tty | |
1da177e4 | 2549 | * |
af9b897e AC |
2550 | * tty_open and tty_release keep up the tty count that contains the |
2551 | * number of opens done on a tty. We cannot use the inode-count, as | |
2552 | * different inodes might point to the same tty. | |
1da177e4 | 2553 | * |
af9b897e AC |
2554 | * Open-counting is needed for pty masters, as well as for keeping |
2555 | * track of serial lines: DTR is dropped when the last close happens. | |
2556 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
2557 | * | |
2558 | * The termios state of a pty is reset on first open so that | |
2559 | * settings don't persist across reuse. | |
2560 | * | |
24ec839c PZ |
2561 | * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. |
2562 | * tty->count should protect the rest. | |
2563 | * ->siglock protects ->signal/->sighand | |
1da177e4 | 2564 | */ |
af9b897e | 2565 | |
1da177e4 LT |
2566 | static int tty_open(struct inode * inode, struct file * filp) |
2567 | { | |
2568 | struct tty_struct *tty; | |
2569 | int noctty, retval; | |
2570 | struct tty_driver *driver; | |
2571 | int index; | |
2572 | dev_t device = inode->i_rdev; | |
2573 | unsigned short saved_flags = filp->f_flags; | |
2574 | ||
2575 | nonseekable_open(inode, filp); | |
2576 | ||
2577 | retry_open: | |
2578 | noctty = filp->f_flags & O_NOCTTY; | |
2579 | index = -1; | |
2580 | retval = 0; | |
2581 | ||
70522e12 | 2582 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2583 | |
2584 | if (device == MKDEV(TTYAUX_MAJOR,0)) { | |
24ec839c PZ |
2585 | tty = get_current_tty(); |
2586 | if (!tty) { | |
70522e12 | 2587 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2588 | return -ENXIO; |
2589 | } | |
24ec839c PZ |
2590 | driver = tty->driver; |
2591 | index = tty->index; | |
1da177e4 LT |
2592 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
2593 | /* noctty = 1; */ | |
2594 | goto got_driver; | |
2595 | } | |
2596 | #ifdef CONFIG_VT | |
2597 | if (device == MKDEV(TTY_MAJOR,0)) { | |
2598 | extern struct tty_driver *console_driver; | |
2599 | driver = console_driver; | |
2600 | index = fg_console; | |
2601 | noctty = 1; | |
2602 | goto got_driver; | |
2603 | } | |
2604 | #endif | |
2605 | if (device == MKDEV(TTYAUX_MAJOR,1)) { | |
2606 | driver = console_device(&index); | |
2607 | if (driver) { | |
2608 | /* Don't let /dev/console block */ | |
2609 | filp->f_flags |= O_NONBLOCK; | |
2610 | noctty = 1; | |
2611 | goto got_driver; | |
2612 | } | |
70522e12 | 2613 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2614 | return -ENODEV; |
2615 | } | |
2616 | ||
2617 | driver = get_tty_driver(device, &index); | |
2618 | if (!driver) { | |
70522e12 | 2619 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2620 | return -ENODEV; |
2621 | } | |
2622 | got_driver: | |
2623 | retval = init_dev(driver, index, &tty); | |
70522e12 | 2624 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2625 | if (retval) |
2626 | return retval; | |
2627 | ||
2628 | filp->private_data = tty; | |
2629 | file_move(filp, &tty->tty_files); | |
2630 | check_tty_count(tty, "tty_open"); | |
2631 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2632 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2633 | noctty = 1; | |
2634 | #ifdef TTY_DEBUG_HANGUP | |
2635 | printk(KERN_DEBUG "opening %s...", tty->name); | |
2636 | #endif | |
2637 | if (!retval) { | |
2638 | if (tty->driver->open) | |
2639 | retval = tty->driver->open(tty, filp); | |
2640 | else | |
2641 | retval = -ENODEV; | |
2642 | } | |
2643 | filp->f_flags = saved_flags; | |
2644 | ||
2645 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) | |
2646 | retval = -EBUSY; | |
2647 | ||
2648 | if (retval) { | |
2649 | #ifdef TTY_DEBUG_HANGUP | |
2650 | printk(KERN_DEBUG "error %d in opening %s...", retval, | |
2651 | tty->name); | |
2652 | #endif | |
2653 | release_dev(filp); | |
2654 | if (retval != -ERESTARTSYS) | |
2655 | return retval; | |
2656 | if (signal_pending(current)) | |
2657 | return retval; | |
2658 | schedule(); | |
2659 | /* | |
2660 | * Need to reset f_op in case a hangup happened. | |
2661 | */ | |
2662 | if (filp->f_op == &hung_up_tty_fops) | |
2663 | filp->f_op = &tty_fops; | |
2664 | goto retry_open; | |
2665 | } | |
24ec839c PZ |
2666 | |
2667 | mutex_lock(&tty_mutex); | |
2668 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2669 | if (!noctty && |
2670 | current->signal->leader && | |
2671 | !current->signal->tty && | |
ab521dc0 | 2672 | tty->session == NULL) |
2a65f1d9 | 2673 | __proc_set_tty(current, tty); |
24ec839c PZ |
2674 | spin_unlock_irq(¤t->sighand->siglock); |
2675 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
2676 | return 0; |
2677 | } | |
2678 | ||
2679 | #ifdef CONFIG_UNIX98_PTYS | |
af9b897e AC |
2680 | /** |
2681 | * ptmx_open - open a unix 98 pty master | |
2682 | * @inode: inode of device file | |
2683 | * @filp: file pointer to tty | |
2684 | * | |
2685 | * Allocate a unix98 pty master device from the ptmx driver. | |
2686 | * | |
2687 | * Locking: tty_mutex protects theinit_dev work. tty->count should | |
2688 | protect the rest. | |
2689 | * allocated_ptys_lock handles the list of free pty numbers | |
2690 | */ | |
2691 | ||
1da177e4 LT |
2692 | static int ptmx_open(struct inode * inode, struct file * filp) |
2693 | { | |
2694 | struct tty_struct *tty; | |
2695 | int retval; | |
2696 | int index; | |
2697 | int idr_ret; | |
2698 | ||
2699 | nonseekable_open(inode, filp); | |
2700 | ||
2701 | /* find a device that is not in use. */ | |
2702 | down(&allocated_ptys_lock); | |
2703 | if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { | |
2704 | up(&allocated_ptys_lock); | |
2705 | return -ENOMEM; | |
2706 | } | |
2707 | idr_ret = idr_get_new(&allocated_ptys, NULL, &index); | |
2708 | if (idr_ret < 0) { | |
2709 | up(&allocated_ptys_lock); | |
2710 | if (idr_ret == -EAGAIN) | |
2711 | return -ENOMEM; | |
2712 | return -EIO; | |
2713 | } | |
2714 | if (index >= pty_limit) { | |
2715 | idr_remove(&allocated_ptys, index); | |
2716 | up(&allocated_ptys_lock); | |
2717 | return -EIO; | |
2718 | } | |
2719 | up(&allocated_ptys_lock); | |
2720 | ||
70522e12 | 2721 | mutex_lock(&tty_mutex); |
1da177e4 | 2722 | retval = init_dev(ptm_driver, index, &tty); |
70522e12 | 2723 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2724 | |
2725 | if (retval) | |
2726 | goto out; | |
2727 | ||
2728 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
2729 | filp->private_data = tty; | |
2730 | file_move(filp, &tty->tty_files); | |
2731 | ||
2732 | retval = -ENOMEM; | |
2733 | if (devpts_pty_new(tty->link)) | |
2734 | goto out1; | |
2735 | ||
2736 | check_tty_count(tty, "tty_open"); | |
2737 | retval = ptm_driver->open(tty, filp); | |
2738 | if (!retval) | |
2739 | return 0; | |
2740 | out1: | |
2741 | release_dev(filp); | |
9453a5ad | 2742 | return retval; |
1da177e4 LT |
2743 | out: |
2744 | down(&allocated_ptys_lock); | |
2745 | idr_remove(&allocated_ptys, index); | |
2746 | up(&allocated_ptys_lock); | |
2747 | return retval; | |
2748 | } | |
2749 | #endif | |
2750 | ||
af9b897e AC |
2751 | /** |
2752 | * tty_release - vfs callback for close | |
2753 | * @inode: inode of tty | |
2754 | * @filp: file pointer for handle to tty | |
2755 | * | |
2756 | * Called the last time each file handle is closed that references | |
2757 | * this tty. There may however be several such references. | |
2758 | * | |
2759 | * Locking: | |
2760 | * Takes bkl. See release_dev | |
2761 | */ | |
2762 | ||
1da177e4 LT |
2763 | static int tty_release(struct inode * inode, struct file * filp) |
2764 | { | |
2765 | lock_kernel(); | |
2766 | release_dev(filp); | |
2767 | unlock_kernel(); | |
2768 | return 0; | |
2769 | } | |
2770 | ||
af9b897e AC |
2771 | /** |
2772 | * tty_poll - check tty status | |
2773 | * @filp: file being polled | |
2774 | * @wait: poll wait structures to update | |
2775 | * | |
2776 | * Call the line discipline polling method to obtain the poll | |
2777 | * status of the device. | |
2778 | * | |
2779 | * Locking: locks called line discipline but ldisc poll method | |
2780 | * may be re-entered freely by other callers. | |
2781 | */ | |
2782 | ||
1da177e4 LT |
2783 | static unsigned int tty_poll(struct file * filp, poll_table * wait) |
2784 | { | |
2785 | struct tty_struct * tty; | |
2786 | struct tty_ldisc *ld; | |
2787 | int ret = 0; | |
2788 | ||
2789 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2790 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) |
1da177e4 LT |
2791 | return 0; |
2792 | ||
2793 | ld = tty_ldisc_ref_wait(tty); | |
2794 | if (ld->poll) | |
2795 | ret = (ld->poll)(tty, filp, wait); | |
2796 | tty_ldisc_deref(ld); | |
2797 | return ret; | |
2798 | } | |
2799 | ||
2800 | static int tty_fasync(int fd, struct file * filp, int on) | |
2801 | { | |
2802 | struct tty_struct * tty; | |
2803 | int retval; | |
2804 | ||
2805 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2806 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) |
1da177e4 LT |
2807 | return 0; |
2808 | ||
2809 | retval = fasync_helper(fd, filp, on, &tty->fasync); | |
2810 | if (retval <= 0) | |
2811 | return retval; | |
2812 | ||
2813 | if (on) { | |
ab521dc0 EB |
2814 | enum pid_type type; |
2815 | struct pid *pid; | |
1da177e4 LT |
2816 | if (!waitqueue_active(&tty->read_wait)) |
2817 | tty->minimum_to_wake = 1; | |
ab521dc0 EB |
2818 | if (tty->pgrp) { |
2819 | pid = tty->pgrp; | |
2820 | type = PIDTYPE_PGID; | |
2821 | } else { | |
2822 | pid = task_pid(current); | |
2823 | type = PIDTYPE_PID; | |
2824 | } | |
2825 | retval = __f_setown(filp, pid, type, 0); | |
1da177e4 LT |
2826 | if (retval) |
2827 | return retval; | |
2828 | } else { | |
2829 | if (!tty->fasync && !waitqueue_active(&tty->read_wait)) | |
2830 | tty->minimum_to_wake = N_TTY_BUF_SIZE; | |
2831 | } | |
2832 | return 0; | |
2833 | } | |
2834 | ||
af9b897e AC |
2835 | /** |
2836 | * tiocsti - fake input character | |
2837 | * @tty: tty to fake input into | |
2838 | * @p: pointer to character | |
2839 | * | |
2840 | * Fake input to a tty device. Does the neccessary locking and | |
2841 | * input management. | |
2842 | * | |
2843 | * FIXME: does not honour flow control ?? | |
2844 | * | |
2845 | * Locking: | |
2846 | * Called functions take tty_ldisc_lock | |
2847 | * current->signal->tty check is safe without locks | |
28298232 AC |
2848 | * |
2849 | * FIXME: may race normal receive processing | |
af9b897e AC |
2850 | */ |
2851 | ||
1da177e4 LT |
2852 | static int tiocsti(struct tty_struct *tty, char __user *p) |
2853 | { | |
2854 | char ch, mbz = 0; | |
2855 | struct tty_ldisc *ld; | |
2856 | ||
2857 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) | |
2858 | return -EPERM; | |
2859 | if (get_user(ch, p)) | |
2860 | return -EFAULT; | |
2861 | ld = tty_ldisc_ref_wait(tty); | |
2862 | ld->receive_buf(tty, &ch, &mbz, 1); | |
2863 | tty_ldisc_deref(ld); | |
2864 | return 0; | |
2865 | } | |
2866 | ||
af9b897e AC |
2867 | /** |
2868 | * tiocgwinsz - implement window query ioctl | |
2869 | * @tty; tty | |
2870 | * @arg: user buffer for result | |
2871 | * | |
808a0d38 | 2872 | * Copies the kernel idea of the window size into the user buffer. |
af9b897e | 2873 | * |
24ec839c | 2874 | * Locking: tty->termios_mutex is taken to ensure the winsize data |
808a0d38 | 2875 | * is consistent. |
af9b897e AC |
2876 | */ |
2877 | ||
1da177e4 LT |
2878 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) |
2879 | { | |
808a0d38 AC |
2880 | int err; |
2881 | ||
5785c95b | 2882 | mutex_lock(&tty->termios_mutex); |
808a0d38 | 2883 | err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); |
5785c95b | 2884 | mutex_unlock(&tty->termios_mutex); |
808a0d38 AC |
2885 | |
2886 | return err ? -EFAULT: 0; | |
1da177e4 LT |
2887 | } |
2888 | ||
af9b897e AC |
2889 | /** |
2890 | * tiocswinsz - implement window size set ioctl | |
2891 | * @tty; tty | |
2892 | * @arg: user buffer for result | |
2893 | * | |
2894 | * Copies the user idea of the window size to the kernel. Traditionally | |
2895 | * this is just advisory information but for the Linux console it | |
2896 | * actually has driver level meaning and triggers a VC resize. | |
2897 | * | |
2898 | * Locking: | |
ca9bda00 AC |
2899 | * Called function use the console_sem is used to ensure we do |
2900 | * not try and resize the console twice at once. | |
24ec839c PZ |
2901 | * The tty->termios_mutex is used to ensure we don't double |
2902 | * resize and get confused. Lock order - tty->termios_mutex before | |
ca9bda00 | 2903 | * console sem |
af9b897e AC |
2904 | */ |
2905 | ||
1da177e4 LT |
2906 | static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, |
2907 | struct winsize __user * arg) | |
2908 | { | |
2909 | struct winsize tmp_ws; | |
2910 | ||
2911 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
2912 | return -EFAULT; | |
ca9bda00 | 2913 | |
5785c95b | 2914 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 2915 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
ca9bda00 AC |
2916 | goto done; |
2917 | ||
1da177e4 LT |
2918 | #ifdef CONFIG_VT |
2919 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { | |
5785c95b AV |
2920 | if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, |
2921 | tmp_ws.ws_row)) { | |
2922 | mutex_unlock(&tty->termios_mutex); | |
ca9bda00 AC |
2923 | return -ENXIO; |
2924 | } | |
1da177e4 LT |
2925 | } |
2926 | #endif | |
ab521dc0 EB |
2927 | if (tty->pgrp) |
2928 | kill_pgrp(tty->pgrp, SIGWINCH, 1); | |
2929 | if ((real_tty->pgrp != tty->pgrp) && real_tty->pgrp) | |
2930 | kill_pgrp(real_tty->pgrp, SIGWINCH, 1); | |
1da177e4 LT |
2931 | tty->winsize = tmp_ws; |
2932 | real_tty->winsize = tmp_ws; | |
ca9bda00 | 2933 | done: |
5785c95b | 2934 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
2935 | return 0; |
2936 | } | |
2937 | ||
af9b897e AC |
2938 | /** |
2939 | * tioccons - allow admin to move logical console | |
2940 | * @file: the file to become console | |
2941 | * | |
2942 | * Allow the adminstrator to move the redirected console device | |
2943 | * | |
2944 | * Locking: uses redirect_lock to guard the redirect information | |
2945 | */ | |
2946 | ||
1da177e4 LT |
2947 | static int tioccons(struct file *file) |
2948 | { | |
2949 | if (!capable(CAP_SYS_ADMIN)) | |
2950 | return -EPERM; | |
2951 | if (file->f_op->write == redirected_tty_write) { | |
2952 | struct file *f; | |
2953 | spin_lock(&redirect_lock); | |
2954 | f = redirect; | |
2955 | redirect = NULL; | |
2956 | spin_unlock(&redirect_lock); | |
2957 | if (f) | |
2958 | fput(f); | |
2959 | return 0; | |
2960 | } | |
2961 | spin_lock(&redirect_lock); | |
2962 | if (redirect) { | |
2963 | spin_unlock(&redirect_lock); | |
2964 | return -EBUSY; | |
2965 | } | |
2966 | get_file(file); | |
2967 | redirect = file; | |
2968 | spin_unlock(&redirect_lock); | |
2969 | return 0; | |
2970 | } | |
2971 | ||
af9b897e AC |
2972 | /** |
2973 | * fionbio - non blocking ioctl | |
2974 | * @file: file to set blocking value | |
2975 | * @p: user parameter | |
2976 | * | |
2977 | * Historical tty interfaces had a blocking control ioctl before | |
2978 | * the generic functionality existed. This piece of history is preserved | |
2979 | * in the expected tty API of posix OS's. | |
2980 | * | |
2981 | * Locking: none, the open fle handle ensures it won't go away. | |
2982 | */ | |
1da177e4 LT |
2983 | |
2984 | static int fionbio(struct file *file, int __user *p) | |
2985 | { | |
2986 | int nonblock; | |
2987 | ||
2988 | if (get_user(nonblock, p)) | |
2989 | return -EFAULT; | |
2990 | ||
2991 | if (nonblock) | |
2992 | file->f_flags |= O_NONBLOCK; | |
2993 | else | |
2994 | file->f_flags &= ~O_NONBLOCK; | |
2995 | return 0; | |
2996 | } | |
2997 | ||
af9b897e AC |
2998 | /** |
2999 | * tiocsctty - set controlling tty | |
3000 | * @tty: tty structure | |
3001 | * @arg: user argument | |
3002 | * | |
3003 | * This ioctl is used to manage job control. It permits a session | |
3004 | * leader to set this tty as the controlling tty for the session. | |
3005 | * | |
3006 | * Locking: | |
28298232 | 3007 | * Takes tty_mutex() to protect tty instance |
24ec839c PZ |
3008 | * Takes tasklist_lock internally to walk sessions |
3009 | * Takes ->siglock() when updating signal->tty | |
af9b897e AC |
3010 | */ |
3011 | ||
1da177e4 LT |
3012 | static int tiocsctty(struct tty_struct *tty, int arg) |
3013 | { | |
24ec839c | 3014 | int ret = 0; |
ab521dc0 | 3015 | if (current->signal->leader && (task_session(current) == tty->session)) |
24ec839c PZ |
3016 | return ret; |
3017 | ||
3018 | mutex_lock(&tty_mutex); | |
1da177e4 LT |
3019 | /* |
3020 | * The process must be a session leader and | |
3021 | * not have a controlling tty already. | |
3022 | */ | |
24ec839c PZ |
3023 | if (!current->signal->leader || current->signal->tty) { |
3024 | ret = -EPERM; | |
3025 | goto unlock; | |
3026 | } | |
3027 | ||
ab521dc0 | 3028 | if (tty->session) { |
1da177e4 LT |
3029 | /* |
3030 | * This tty is already the controlling | |
3031 | * tty for another session group! | |
3032 | */ | |
3033 | if ((arg == 1) && capable(CAP_SYS_ADMIN)) { | |
3034 | /* | |
3035 | * Steal it away | |
3036 | */ | |
1da177e4 | 3037 | read_lock(&tasklist_lock); |
24ec839c | 3038 | session_clear_tty(tty->session); |
1da177e4 | 3039 | read_unlock(&tasklist_lock); |
24ec839c PZ |
3040 | } else { |
3041 | ret = -EPERM; | |
3042 | goto unlock; | |
3043 | } | |
1da177e4 | 3044 | } |
24ec839c PZ |
3045 | proc_set_tty(current, tty); |
3046 | unlock: | |
28298232 | 3047 | mutex_unlock(&tty_mutex); |
24ec839c | 3048 | return ret; |
1da177e4 LT |
3049 | } |
3050 | ||
af9b897e AC |
3051 | /** |
3052 | * tiocgpgrp - get process group | |
3053 | * @tty: tty passed by user | |
3054 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3055 | * @p: returned pid | |
3056 | * | |
3057 | * Obtain the process group of the tty. If there is no process group | |
3058 | * return an error. | |
3059 | * | |
24ec839c | 3060 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3061 | */ |
3062 | ||
1da177e4 LT |
3063 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3064 | { | |
3065 | /* | |
3066 | * (tty == real_tty) is a cheap way of | |
3067 | * testing if the tty is NOT a master pty. | |
3068 | */ | |
3069 | if (tty == real_tty && current->signal->tty != real_tty) | |
3070 | return -ENOTTY; | |
ab521dc0 | 3071 | return put_user(pid_nr(real_tty->pgrp), p); |
1da177e4 LT |
3072 | } |
3073 | ||
af9b897e AC |
3074 | /** |
3075 | * tiocspgrp - attempt to set process group | |
3076 | * @tty: tty passed by user | |
3077 | * @real_tty: tty side device matching tty passed by user | |
3078 | * @p: pid pointer | |
3079 | * | |
3080 | * Set the process group of the tty to the session passed. Only | |
3081 | * permitted where the tty session is our session. | |
3082 | * | |
3083 | * Locking: None | |
af9b897e AC |
3084 | */ |
3085 | ||
1da177e4 LT |
3086 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3087 | { | |
04a2e6a5 EB |
3088 | struct pid *pgrp; |
3089 | pid_t pgrp_nr; | |
1da177e4 LT |
3090 | int retval = tty_check_change(real_tty); |
3091 | ||
3092 | if (retval == -EIO) | |
3093 | return -ENOTTY; | |
3094 | if (retval) | |
3095 | return retval; | |
3096 | if (!current->signal->tty || | |
3097 | (current->signal->tty != real_tty) || | |
ab521dc0 | 3098 | (real_tty->session != task_session(current))) |
1da177e4 | 3099 | return -ENOTTY; |
04a2e6a5 | 3100 | if (get_user(pgrp_nr, p)) |
1da177e4 | 3101 | return -EFAULT; |
04a2e6a5 | 3102 | if (pgrp_nr < 0) |
1da177e4 | 3103 | return -EINVAL; |
04a2e6a5 EB |
3104 | rcu_read_lock(); |
3105 | pgrp = find_pid(pgrp_nr); | |
3106 | retval = -ESRCH; | |
3107 | if (!pgrp) | |
3108 | goto out_unlock; | |
3109 | retval = -EPERM; | |
3110 | if (session_of_pgrp(pgrp) != task_session(current)) | |
3111 | goto out_unlock; | |
3112 | retval = 0; | |
ab521dc0 EB |
3113 | put_pid(real_tty->pgrp); |
3114 | real_tty->pgrp = get_pid(pgrp); | |
04a2e6a5 EB |
3115 | out_unlock: |
3116 | rcu_read_unlock(); | |
3117 | return retval; | |
1da177e4 LT |
3118 | } |
3119 | ||
af9b897e AC |
3120 | /** |
3121 | * tiocgsid - get session id | |
3122 | * @tty: tty passed by user | |
3123 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3124 | * @p: pointer to returned session id | |
3125 | * | |
3126 | * Obtain the session id of the tty. If there is no session | |
3127 | * return an error. | |
3128 | * | |
24ec839c | 3129 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3130 | */ |
3131 | ||
1da177e4 LT |
3132 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3133 | { | |
3134 | /* | |
3135 | * (tty == real_tty) is a cheap way of | |
3136 | * testing if the tty is NOT a master pty. | |
3137 | */ | |
3138 | if (tty == real_tty && current->signal->tty != real_tty) | |
3139 | return -ENOTTY; | |
ab521dc0 | 3140 | if (!real_tty->session) |
1da177e4 | 3141 | return -ENOTTY; |
ab521dc0 | 3142 | return put_user(pid_nr(real_tty->session), p); |
1da177e4 LT |
3143 | } |
3144 | ||
af9b897e AC |
3145 | /** |
3146 | * tiocsetd - set line discipline | |
3147 | * @tty: tty device | |
3148 | * @p: pointer to user data | |
3149 | * | |
3150 | * Set the line discipline according to user request. | |
3151 | * | |
3152 | * Locking: see tty_set_ldisc, this function is just a helper | |
3153 | */ | |
3154 | ||
1da177e4 LT |
3155 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
3156 | { | |
3157 | int ldisc; | |
3158 | ||
3159 | if (get_user(ldisc, p)) | |
3160 | return -EFAULT; | |
3161 | return tty_set_ldisc(tty, ldisc); | |
3162 | } | |
3163 | ||
af9b897e AC |
3164 | /** |
3165 | * send_break - performed time break | |
3166 | * @tty: device to break on | |
3167 | * @duration: timeout in mS | |
3168 | * | |
3169 | * Perform a timed break on hardware that lacks its own driver level | |
3170 | * timed break functionality. | |
3171 | * | |
3172 | * Locking: | |
28298232 | 3173 | * atomic_write_lock serializes |
af9b897e | 3174 | * |
af9b897e AC |
3175 | */ |
3176 | ||
b20f3ae5 | 3177 | static int send_break(struct tty_struct *tty, unsigned int duration) |
1da177e4 | 3178 | { |
9c1729db | 3179 | if (tty_write_lock(tty, 0) < 0) |
28298232 | 3180 | return -EINTR; |
1da177e4 | 3181 | tty->driver->break_ctl(tty, -1); |
9c1729db | 3182 | if (!signal_pending(current)) |
b20f3ae5 | 3183 | msleep_interruptible(duration); |
1da177e4 | 3184 | tty->driver->break_ctl(tty, 0); |
9c1729db | 3185 | tty_write_unlock(tty); |
1da177e4 LT |
3186 | if (signal_pending(current)) |
3187 | return -EINTR; | |
3188 | return 0; | |
3189 | } | |
3190 | ||
af9b897e AC |
3191 | /** |
3192 | * tiocmget - get modem status | |
3193 | * @tty: tty device | |
3194 | * @file: user file pointer | |
3195 | * @p: pointer to result | |
3196 | * | |
3197 | * Obtain the modem status bits from the tty driver if the feature | |
3198 | * is supported. Return -EINVAL if it is not available. | |
3199 | * | |
3200 | * Locking: none (up to the driver) | |
3201 | */ | |
3202 | ||
3203 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) | |
1da177e4 LT |
3204 | { |
3205 | int retval = -EINVAL; | |
3206 | ||
3207 | if (tty->driver->tiocmget) { | |
3208 | retval = tty->driver->tiocmget(tty, file); | |
3209 | ||
3210 | if (retval >= 0) | |
3211 | retval = put_user(retval, p); | |
3212 | } | |
3213 | return retval; | |
3214 | } | |
3215 | ||
af9b897e AC |
3216 | /** |
3217 | * tiocmset - set modem status | |
3218 | * @tty: tty device | |
3219 | * @file: user file pointer | |
3220 | * @cmd: command - clear bits, set bits or set all | |
3221 | * @p: pointer to desired bits | |
3222 | * | |
3223 | * Set the modem status bits from the tty driver if the feature | |
3224 | * is supported. Return -EINVAL if it is not available. | |
3225 | * | |
3226 | * Locking: none (up to the driver) | |
3227 | */ | |
3228 | ||
3229 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, | |
1da177e4 LT |
3230 | unsigned __user *p) |
3231 | { | |
3232 | int retval = -EINVAL; | |
3233 | ||
3234 | if (tty->driver->tiocmset) { | |
3235 | unsigned int set, clear, val; | |
3236 | ||
3237 | retval = get_user(val, p); | |
3238 | if (retval) | |
3239 | return retval; | |
3240 | ||
3241 | set = clear = 0; | |
3242 | switch (cmd) { | |
3243 | case TIOCMBIS: | |
3244 | set = val; | |
3245 | break; | |
3246 | case TIOCMBIC: | |
3247 | clear = val; | |
3248 | break; | |
3249 | case TIOCMSET: | |
3250 | set = val; | |
3251 | clear = ~val; | |
3252 | break; | |
3253 | } | |
3254 | ||
3255 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3256 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3257 | ||
3258 | retval = tty->driver->tiocmset(tty, file, set, clear); | |
3259 | } | |
3260 | return retval; | |
3261 | } | |
3262 | ||
3263 | /* | |
3264 | * Split this up, as gcc can choke on it otherwise.. | |
3265 | */ | |
3266 | int tty_ioctl(struct inode * inode, struct file * file, | |
3267 | unsigned int cmd, unsigned long arg) | |
3268 | { | |
3269 | struct tty_struct *tty, *real_tty; | |
3270 | void __user *p = (void __user *)arg; | |
3271 | int retval; | |
3272 | struct tty_ldisc *ld; | |
3273 | ||
3274 | tty = (struct tty_struct *)file->private_data; | |
3275 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3276 | return -EINVAL; | |
3277 | ||
28298232 AC |
3278 | /* CHECKME: is this safe as one end closes ? */ |
3279 | ||
1da177e4 LT |
3280 | real_tty = tty; |
3281 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
3282 | tty->driver->subtype == PTY_TYPE_MASTER) | |
3283 | real_tty = tty->link; | |
3284 | ||
3285 | /* | |
3286 | * Break handling by driver | |
3287 | */ | |
3288 | if (!tty->driver->break_ctl) { | |
3289 | switch(cmd) { | |
3290 | case TIOCSBRK: | |
3291 | case TIOCCBRK: | |
3292 | if (tty->driver->ioctl) | |
3293 | return tty->driver->ioctl(tty, file, cmd, arg); | |
3294 | return -EINVAL; | |
3295 | ||
3296 | /* These two ioctl's always return success; even if */ | |
3297 | /* the driver doesn't support them. */ | |
3298 | case TCSBRK: | |
3299 | case TCSBRKP: | |
3300 | if (!tty->driver->ioctl) | |
3301 | return 0; | |
3302 | retval = tty->driver->ioctl(tty, file, cmd, arg); | |
3303 | if (retval == -ENOIOCTLCMD) | |
3304 | retval = 0; | |
3305 | return retval; | |
3306 | } | |
3307 | } | |
3308 | ||
3309 | /* | |
3310 | * Factor out some common prep work | |
3311 | */ | |
3312 | switch (cmd) { | |
3313 | case TIOCSETD: | |
3314 | case TIOCSBRK: | |
3315 | case TIOCCBRK: | |
3316 | case TCSBRK: | |
3317 | case TCSBRKP: | |
3318 | retval = tty_check_change(tty); | |
3319 | if (retval) | |
3320 | return retval; | |
3321 | if (cmd != TIOCCBRK) { | |
3322 | tty_wait_until_sent(tty, 0); | |
3323 | if (signal_pending(current)) | |
3324 | return -EINTR; | |
3325 | } | |
3326 | break; | |
3327 | } | |
3328 | ||
3329 | switch (cmd) { | |
3330 | case TIOCSTI: | |
3331 | return tiocsti(tty, p); | |
3332 | case TIOCGWINSZ: | |
3333 | return tiocgwinsz(tty, p); | |
3334 | case TIOCSWINSZ: | |
3335 | return tiocswinsz(tty, real_tty, p); | |
3336 | case TIOCCONS: | |
3337 | return real_tty!=tty ? -EINVAL : tioccons(file); | |
3338 | case FIONBIO: | |
3339 | return fionbio(file, p); | |
3340 | case TIOCEXCL: | |
3341 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
3342 | return 0; | |
3343 | case TIOCNXCL: | |
3344 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
3345 | return 0; | |
3346 | case TIOCNOTTY: | |
3347 | if (current->signal->tty != tty) | |
3348 | return -ENOTTY; | |
98a27ba4 | 3349 | no_tty(); |
1da177e4 LT |
3350 | return 0; |
3351 | case TIOCSCTTY: | |
3352 | return tiocsctty(tty, arg); | |
3353 | case TIOCGPGRP: | |
3354 | return tiocgpgrp(tty, real_tty, p); | |
3355 | case TIOCSPGRP: | |
3356 | return tiocspgrp(tty, real_tty, p); | |
3357 | case TIOCGSID: | |
3358 | return tiocgsid(tty, real_tty, p); | |
3359 | case TIOCGETD: | |
3360 | /* FIXME: check this is ok */ | |
3361 | return put_user(tty->ldisc.num, (int __user *)p); | |
3362 | case TIOCSETD: | |
3363 | return tiocsetd(tty, p); | |
3364 | #ifdef CONFIG_VT | |
3365 | case TIOCLINUX: | |
3366 | return tioclinux(tty, arg); | |
3367 | #endif | |
3368 | /* | |
3369 | * Break handling | |
3370 | */ | |
3371 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
3372 | tty->driver->break_ctl(tty, -1); | |
3373 | return 0; | |
3374 | ||
3375 | case TIOCCBRK: /* Turn break off, unconditionally */ | |
3376 | tty->driver->break_ctl(tty, 0); | |
3377 | return 0; | |
3378 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
283fef59 PF |
3379 | /* non-zero arg means wait for all output data |
3380 | * to be sent (performed above) but don't send break. | |
3381 | * This is used by the tcdrain() termios function. | |
1da177e4 LT |
3382 | */ |
3383 | if (!arg) | |
b20f3ae5 | 3384 | return send_break(tty, 250); |
1da177e4 LT |
3385 | return 0; |
3386 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
b20f3ae5 | 3387 | return send_break(tty, arg ? arg*100 : 250); |
1da177e4 LT |
3388 | |
3389 | case TIOCMGET: | |
3390 | return tty_tiocmget(tty, file, p); | |
3391 | ||
3392 | case TIOCMSET: | |
3393 | case TIOCMBIC: | |
3394 | case TIOCMBIS: | |
3395 | return tty_tiocmset(tty, file, cmd, p); | |
c5c34d48 PF |
3396 | case TCFLSH: |
3397 | switch (arg) { | |
3398 | case TCIFLUSH: | |
3399 | case TCIOFLUSH: | |
3400 | /* flush tty buffer and allow ldisc to process ioctl */ | |
3401 | tty_buffer_flush(tty); | |
3402 | break; | |
3403 | } | |
3404 | break; | |
1da177e4 LT |
3405 | } |
3406 | if (tty->driver->ioctl) { | |
3407 | retval = (tty->driver->ioctl)(tty, file, cmd, arg); | |
3408 | if (retval != -ENOIOCTLCMD) | |
3409 | return retval; | |
3410 | } | |
3411 | ld = tty_ldisc_ref_wait(tty); | |
3412 | retval = -EINVAL; | |
3413 | if (ld->ioctl) { | |
3414 | retval = ld->ioctl(tty, file, cmd, arg); | |
3415 | if (retval == -ENOIOCTLCMD) | |
3416 | retval = -EINVAL; | |
3417 | } | |
3418 | tty_ldisc_deref(ld); | |
3419 | return retval; | |
3420 | } | |
3421 | ||
e10cc1df PF |
3422 | #ifdef CONFIG_COMPAT |
3423 | static long tty_compat_ioctl(struct file * file, unsigned int cmd, | |
3424 | unsigned long arg) | |
3425 | { | |
3426 | struct inode *inode = file->f_dentry->d_inode; | |
3427 | struct tty_struct *tty = file->private_data; | |
3428 | struct tty_ldisc *ld; | |
3429 | int retval = -ENOIOCTLCMD; | |
3430 | ||
3431 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3432 | return -EINVAL; | |
3433 | ||
3434 | if (tty->driver->compat_ioctl) { | |
3435 | retval = (tty->driver->compat_ioctl)(tty, file, cmd, arg); | |
3436 | if (retval != -ENOIOCTLCMD) | |
3437 | return retval; | |
3438 | } | |
3439 | ||
3440 | ld = tty_ldisc_ref_wait(tty); | |
3441 | if (ld->compat_ioctl) | |
3442 | retval = ld->compat_ioctl(tty, file, cmd, arg); | |
3443 | tty_ldisc_deref(ld); | |
3444 | ||
3445 | return retval; | |
3446 | } | |
3447 | #endif | |
1da177e4 LT |
3448 | |
3449 | /* | |
3450 | * This implements the "Secure Attention Key" --- the idea is to | |
3451 | * prevent trojan horses by killing all processes associated with this | |
3452 | * tty when the user hits the "Secure Attention Key". Required for | |
3453 | * super-paranoid applications --- see the Orange Book for more details. | |
3454 | * | |
3455 | * This code could be nicer; ideally it should send a HUP, wait a few | |
3456 | * seconds, then send a INT, and then a KILL signal. But you then | |
3457 | * have to coordinate with the init process, since all processes associated | |
3458 | * with the current tty must be dead before the new getty is allowed | |
3459 | * to spawn. | |
3460 | * | |
3461 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
3462 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
3463 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
3464 | * | |
3465 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
3466 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
3467 | */ | |
8b6312f4 | 3468 | void __do_SAK(struct tty_struct *tty) |
1da177e4 LT |
3469 | { |
3470 | #ifdef TTY_SOFT_SAK | |
3471 | tty_hangup(tty); | |
3472 | #else | |
652486fb | 3473 | struct task_struct *g, *p; |
ab521dc0 | 3474 | struct pid *session; |
1da177e4 LT |
3475 | int i; |
3476 | struct file *filp; | |
badf1662 | 3477 | struct fdtable *fdt; |
1da177e4 LT |
3478 | |
3479 | if (!tty) | |
3480 | return; | |
24ec839c | 3481 | session = tty->session; |
1da177e4 | 3482 | |
b3f13deb | 3483 | tty_ldisc_flush(tty); |
1da177e4 LT |
3484 | |
3485 | if (tty->driver->flush_buffer) | |
3486 | tty->driver->flush_buffer(tty); | |
3487 | ||
3488 | read_lock(&tasklist_lock); | |
652486fb | 3489 | /* Kill the entire session */ |
ab521dc0 | 3490 | do_each_pid_task(session, PIDTYPE_SID, p) { |
652486fb | 3491 | printk(KERN_NOTICE "SAK: killed process %d" |
937949d9 | 3492 | " (%s): process_session(p)==tty->session\n", |
652486fb EB |
3493 | p->pid, p->comm); |
3494 | send_sig(SIGKILL, p, 1); | |
ab521dc0 | 3495 | } while_each_pid_task(session, PIDTYPE_SID, p); |
652486fb EB |
3496 | /* Now kill any processes that happen to have the |
3497 | * tty open. | |
3498 | */ | |
3499 | do_each_thread(g, p) { | |
3500 | if (p->signal->tty == tty) { | |
1da177e4 | 3501 | printk(KERN_NOTICE "SAK: killed process %d" |
937949d9 | 3502 | " (%s): process_session(p)==tty->session\n", |
1da177e4 LT |
3503 | p->pid, p->comm); |
3504 | send_sig(SIGKILL, p, 1); | |
3505 | continue; | |
3506 | } | |
3507 | task_lock(p); | |
3508 | if (p->files) { | |
ca99c1da DS |
3509 | /* |
3510 | * We don't take a ref to the file, so we must | |
3511 | * hold ->file_lock instead. | |
3512 | */ | |
3513 | spin_lock(&p->files->file_lock); | |
badf1662 DS |
3514 | fdt = files_fdtable(p->files); |
3515 | for (i=0; i < fdt->max_fds; i++) { | |
1da177e4 LT |
3516 | filp = fcheck_files(p->files, i); |
3517 | if (!filp) | |
3518 | continue; | |
3519 | if (filp->f_op->read == tty_read && | |
3520 | filp->private_data == tty) { | |
3521 | printk(KERN_NOTICE "SAK: killed process %d" | |
3522 | " (%s): fd#%d opened to the tty\n", | |
3523 | p->pid, p->comm, i); | |
20ac9437 | 3524 | force_sig(SIGKILL, p); |
1da177e4 LT |
3525 | break; |
3526 | } | |
3527 | } | |
ca99c1da | 3528 | spin_unlock(&p->files->file_lock); |
1da177e4 LT |
3529 | } |
3530 | task_unlock(p); | |
652486fb | 3531 | } while_each_thread(g, p); |
1da177e4 LT |
3532 | read_unlock(&tasklist_lock); |
3533 | #endif | |
3534 | } | |
3535 | ||
8b6312f4 EB |
3536 | static void do_SAK_work(struct work_struct *work) |
3537 | { | |
3538 | struct tty_struct *tty = | |
3539 | container_of(work, struct tty_struct, SAK_work); | |
3540 | __do_SAK(tty); | |
3541 | } | |
3542 | ||
1da177e4 LT |
3543 | /* |
3544 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
3545 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
3546 | * the values which we write to it will be identical to the values which it | |
3547 | * already has. --akpm | |
3548 | */ | |
3549 | void do_SAK(struct tty_struct *tty) | |
3550 | { | |
3551 | if (!tty) | |
3552 | return; | |
1da177e4 LT |
3553 | schedule_work(&tty->SAK_work); |
3554 | } | |
3555 | ||
3556 | EXPORT_SYMBOL(do_SAK); | |
3557 | ||
af9b897e AC |
3558 | /** |
3559 | * flush_to_ldisc | |
65f27f38 | 3560 | * @work: tty structure passed from work queue. |
af9b897e AC |
3561 | * |
3562 | * This routine is called out of the software interrupt to flush data | |
3563 | * from the buffer chain to the line discipline. | |
3564 | * | |
3565 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
3566 | * while invoking the line discipline receive_buf method. The | |
3567 | * receive_buf method is single threaded for each tty instance. | |
1da177e4 LT |
3568 | */ |
3569 | ||
65f27f38 | 3570 | static void flush_to_ldisc(struct work_struct *work) |
1da177e4 | 3571 | { |
65f27f38 DH |
3572 | struct tty_struct *tty = |
3573 | container_of(work, struct tty_struct, buf.work.work); | |
1da177e4 LT |
3574 | unsigned long flags; |
3575 | struct tty_ldisc *disc; | |
2c3bb20f | 3576 | struct tty_buffer *tbuf, *head; |
8977d929 PF |
3577 | char *char_buf; |
3578 | unsigned char *flag_buf; | |
1da177e4 LT |
3579 | |
3580 | disc = tty_ldisc_ref(tty); | |
3581 | if (disc == NULL) /* !TTY_LDISC */ | |
3582 | return; | |
3583 | ||
808249ce | 3584 | spin_lock_irqsave(&tty->buf.lock, flags); |
2c3bb20f PF |
3585 | head = tty->buf.head; |
3586 | if (head != NULL) { | |
3587 | tty->buf.head = NULL; | |
3588 | for (;;) { | |
3589 | int count = head->commit - head->read; | |
3590 | if (!count) { | |
3591 | if (head->next == NULL) | |
3592 | break; | |
3593 | tbuf = head; | |
3594 | head = head->next; | |
3595 | tty_buffer_free(tty, tbuf); | |
3596 | continue; | |
3597 | } | |
3598 | if (!tty->receive_room) { | |
3599 | schedule_delayed_work(&tty->buf.work, 1); | |
3600 | break; | |
3601 | } | |
3602 | if (count > tty->receive_room) | |
3603 | count = tty->receive_room; | |
3604 | char_buf = head->char_buf_ptr + head->read; | |
3605 | flag_buf = head->flag_buf_ptr + head->read; | |
3606 | head->read += count; | |
8977d929 PF |
3607 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3608 | disc->receive_buf(tty, char_buf, flag_buf, count); | |
3609 | spin_lock_irqsave(&tty->buf.lock, flags); | |
3610 | } | |
2c3bb20f | 3611 | tty->buf.head = head; |
33f0f88f | 3612 | } |
808249ce | 3613 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
817d6d3b | 3614 | |
1da177e4 LT |
3615 | tty_ldisc_deref(disc); |
3616 | } | |
3617 | ||
1da177e4 LT |
3618 | /** |
3619 | * tty_flip_buffer_push - terminal | |
3620 | * @tty: tty to push | |
3621 | * | |
3622 | * Queue a push of the terminal flip buffers to the line discipline. This | |
3623 | * function must not be called from IRQ context if tty->low_latency is set. | |
3624 | * | |
3625 | * In the event of the queue being busy for flipping the work will be | |
3626 | * held off and retried later. | |
af9b897e AC |
3627 | * |
3628 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
1da177e4 LT |
3629 | */ |
3630 | ||
3631 | void tty_flip_buffer_push(struct tty_struct *tty) | |
3632 | { | |
808249ce PF |
3633 | unsigned long flags; |
3634 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 3635 | if (tty->buf.tail != NULL) |
8977d929 | 3636 | tty->buf.tail->commit = tty->buf.tail->used; |
808249ce PF |
3637 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3638 | ||
1da177e4 | 3639 | if (tty->low_latency) |
65f27f38 | 3640 | flush_to_ldisc(&tty->buf.work.work); |
1da177e4 | 3641 | else |
33f0f88f | 3642 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
3643 | } |
3644 | ||
3645 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
3646 | ||
33f0f88f | 3647 | |
af9b897e AC |
3648 | /** |
3649 | * initialize_tty_struct | |
3650 | * @tty: tty to initialize | |
3651 | * | |
3652 | * This subroutine initializes a tty structure that has been newly | |
3653 | * allocated. | |
3654 | * | |
3655 | * Locking: none - tty in question must not be exposed at this point | |
1da177e4 | 3656 | */ |
af9b897e | 3657 | |
1da177e4 LT |
3658 | static void initialize_tty_struct(struct tty_struct *tty) |
3659 | { | |
3660 | memset(tty, 0, sizeof(struct tty_struct)); | |
3661 | tty->magic = TTY_MAGIC; | |
3662 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
ab521dc0 EB |
3663 | tty->session = NULL; |
3664 | tty->pgrp = NULL; | |
1da177e4 | 3665 | tty->overrun_time = jiffies; |
33f0f88f AC |
3666 | tty->buf.head = tty->buf.tail = NULL; |
3667 | tty_buffer_init(tty); | |
65f27f38 | 3668 | INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); |
33f0f88f | 3669 | init_MUTEX(&tty->buf.pty_sem); |
5785c95b | 3670 | mutex_init(&tty->termios_mutex); |
1da177e4 LT |
3671 | init_waitqueue_head(&tty->write_wait); |
3672 | init_waitqueue_head(&tty->read_wait); | |
65f27f38 | 3673 | INIT_WORK(&tty->hangup_work, do_tty_hangup); |
70522e12 IM |
3674 | mutex_init(&tty->atomic_read_lock); |
3675 | mutex_init(&tty->atomic_write_lock); | |
1da177e4 LT |
3676 | spin_lock_init(&tty->read_lock); |
3677 | INIT_LIST_HEAD(&tty->tty_files); | |
7f1f86a0 | 3678 | INIT_WORK(&tty->SAK_work, do_SAK_work); |
1da177e4 LT |
3679 | } |
3680 | ||
3681 | /* | |
3682 | * The default put_char routine if the driver did not define one. | |
3683 | */ | |
af9b897e | 3684 | |
1da177e4 LT |
3685 | static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) |
3686 | { | |
3687 | tty->driver->write(tty, &ch, 1); | |
3688 | } | |
3689 | ||
7fe845d1 | 3690 | static struct class *tty_class; |
1da177e4 LT |
3691 | |
3692 | /** | |
af9b897e AC |
3693 | * tty_register_device - register a tty device |
3694 | * @driver: the tty driver that describes the tty device | |
3695 | * @index: the index in the tty driver for this tty device | |
3696 | * @device: a struct device that is associated with this tty device. | |
3697 | * This field is optional, if there is no known struct device | |
3698 | * for this tty device it can be set to NULL safely. | |
1da177e4 | 3699 | * |
01107d34 GKH |
3700 | * Returns a pointer to the struct device for this tty device |
3701 | * (or ERR_PTR(-EFOO) on error). | |
1cdcb6b4 | 3702 | * |
af9b897e AC |
3703 | * This call is required to be made to register an individual tty device |
3704 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
3705 | * that bit is not set, this function should not be called by a tty | |
3706 | * driver. | |
3707 | * | |
3708 | * Locking: ?? | |
1da177e4 | 3709 | */ |
af9b897e | 3710 | |
01107d34 GKH |
3711 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
3712 | struct device *device) | |
1da177e4 LT |
3713 | { |
3714 | char name[64]; | |
3715 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; | |
3716 | ||
3717 | if (index >= driver->num) { | |
3718 | printk(KERN_ERR "Attempt to register invalid tty line number " | |
3719 | " (%d).\n", index); | |
1cdcb6b4 | 3720 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
3721 | } |
3722 | ||
1da177e4 LT |
3723 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
3724 | pty_line_name(driver, index, name); | |
3725 | else | |
3726 | tty_line_name(driver, index, name); | |
1cdcb6b4 | 3727 | |
01107d34 | 3728 | return device_create(tty_class, device, dev, name); |
1da177e4 LT |
3729 | } |
3730 | ||
3731 | /** | |
af9b897e AC |
3732 | * tty_unregister_device - unregister a tty device |
3733 | * @driver: the tty driver that describes the tty device | |
3734 | * @index: the index in the tty driver for this tty device | |
1da177e4 | 3735 | * |
af9b897e AC |
3736 | * If a tty device is registered with a call to tty_register_device() then |
3737 | * this function must be called when the tty device is gone. | |
3738 | * | |
3739 | * Locking: ?? | |
1da177e4 | 3740 | */ |
af9b897e | 3741 | |
1da177e4 LT |
3742 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
3743 | { | |
01107d34 | 3744 | device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); |
1da177e4 LT |
3745 | } |
3746 | ||
3747 | EXPORT_SYMBOL(tty_register_device); | |
3748 | EXPORT_SYMBOL(tty_unregister_device); | |
3749 | ||
3750 | struct tty_driver *alloc_tty_driver(int lines) | |
3751 | { | |
3752 | struct tty_driver *driver; | |
3753 | ||
506eb99a | 3754 | driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); |
1da177e4 | 3755 | if (driver) { |
1da177e4 LT |
3756 | driver->magic = TTY_DRIVER_MAGIC; |
3757 | driver->num = lines; | |
3758 | /* later we'll move allocation of tables here */ | |
3759 | } | |
3760 | return driver; | |
3761 | } | |
3762 | ||
3763 | void put_tty_driver(struct tty_driver *driver) | |
3764 | { | |
3765 | kfree(driver); | |
3766 | } | |
3767 | ||
b68e31d0 JD |
3768 | void tty_set_operations(struct tty_driver *driver, |
3769 | const struct tty_operations *op) | |
1da177e4 LT |
3770 | { |
3771 | driver->open = op->open; | |
3772 | driver->close = op->close; | |
3773 | driver->write = op->write; | |
3774 | driver->put_char = op->put_char; | |
3775 | driver->flush_chars = op->flush_chars; | |
3776 | driver->write_room = op->write_room; | |
3777 | driver->chars_in_buffer = op->chars_in_buffer; | |
3778 | driver->ioctl = op->ioctl; | |
e10cc1df | 3779 | driver->compat_ioctl = op->compat_ioctl; |
1da177e4 LT |
3780 | driver->set_termios = op->set_termios; |
3781 | driver->throttle = op->throttle; | |
3782 | driver->unthrottle = op->unthrottle; | |
3783 | driver->stop = op->stop; | |
3784 | driver->start = op->start; | |
3785 | driver->hangup = op->hangup; | |
3786 | driver->break_ctl = op->break_ctl; | |
3787 | driver->flush_buffer = op->flush_buffer; | |
3788 | driver->set_ldisc = op->set_ldisc; | |
3789 | driver->wait_until_sent = op->wait_until_sent; | |
3790 | driver->send_xchar = op->send_xchar; | |
3791 | driver->read_proc = op->read_proc; | |
3792 | driver->write_proc = op->write_proc; | |
3793 | driver->tiocmget = op->tiocmget; | |
3794 | driver->tiocmset = op->tiocmset; | |
3795 | } | |
3796 | ||
3797 | ||
3798 | EXPORT_SYMBOL(alloc_tty_driver); | |
3799 | EXPORT_SYMBOL(put_tty_driver); | |
3800 | EXPORT_SYMBOL(tty_set_operations); | |
3801 | ||
3802 | /* | |
3803 | * Called by a tty driver to register itself. | |
3804 | */ | |
3805 | int tty_register_driver(struct tty_driver *driver) | |
3806 | { | |
3807 | int error; | |
3808 | int i; | |
3809 | dev_t dev; | |
3810 | void **p = NULL; | |
3811 | ||
3812 | if (driver->flags & TTY_DRIVER_INSTALLED) | |
3813 | return 0; | |
3814 | ||
543691a6 AW |
3815 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { |
3816 | p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); | |
1da177e4 LT |
3817 | if (!p) |
3818 | return -ENOMEM; | |
1da177e4 LT |
3819 | } |
3820 | ||
3821 | if (!driver->major) { | |
3822 | error = alloc_chrdev_region(&dev, driver->minor_start, driver->num, | |
e5717c48 | 3823 | driver->name); |
1da177e4 LT |
3824 | if (!error) { |
3825 | driver->major = MAJOR(dev); | |
3826 | driver->minor_start = MINOR(dev); | |
3827 | } | |
3828 | } else { | |
3829 | dev = MKDEV(driver->major, driver->minor_start); | |
e5717c48 | 3830 | error = register_chrdev_region(dev, driver->num, driver->name); |
1da177e4 LT |
3831 | } |
3832 | if (error < 0) { | |
3833 | kfree(p); | |
3834 | return error; | |
3835 | } | |
3836 | ||
3837 | if (p) { | |
3838 | driver->ttys = (struct tty_struct **)p; | |
edc6afc5 AC |
3839 | driver->termios = (struct ktermios **)(p + driver->num); |
3840 | driver->termios_locked = (struct ktermios **)(p + driver->num * 2); | |
1da177e4 LT |
3841 | } else { |
3842 | driver->ttys = NULL; | |
3843 | driver->termios = NULL; | |
3844 | driver->termios_locked = NULL; | |
3845 | } | |
3846 | ||
3847 | cdev_init(&driver->cdev, &tty_fops); | |
3848 | driver->cdev.owner = driver->owner; | |
3849 | error = cdev_add(&driver->cdev, dev, driver->num); | |
3850 | if (error) { | |
1da177e4 LT |
3851 | unregister_chrdev_region(dev, driver->num); |
3852 | driver->ttys = NULL; | |
3853 | driver->termios = driver->termios_locked = NULL; | |
3854 | kfree(p); | |
3855 | return error; | |
3856 | } | |
3857 | ||
3858 | if (!driver->put_char) | |
3859 | driver->put_char = tty_default_put_char; | |
3860 | ||
ca509f69 | 3861 | mutex_lock(&tty_mutex); |
1da177e4 | 3862 | list_add(&driver->tty_drivers, &tty_drivers); |
ca509f69 | 3863 | mutex_unlock(&tty_mutex); |
1da177e4 | 3864 | |
331b8319 | 3865 | if ( !(driver->flags & TTY_DRIVER_DYNAMIC_DEV) ) { |
1da177e4 LT |
3866 | for(i = 0; i < driver->num; i++) |
3867 | tty_register_device(driver, i, NULL); | |
3868 | } | |
3869 | proc_tty_register_driver(driver); | |
3870 | return 0; | |
3871 | } | |
3872 | ||
3873 | EXPORT_SYMBOL(tty_register_driver); | |
3874 | ||
3875 | /* | |
3876 | * Called by a tty driver to unregister itself. | |
3877 | */ | |
3878 | int tty_unregister_driver(struct tty_driver *driver) | |
3879 | { | |
3880 | int i; | |
edc6afc5 | 3881 | struct ktermios *tp; |
1da177e4 LT |
3882 | void *p; |
3883 | ||
3884 | if (driver->refcount) | |
3885 | return -EBUSY; | |
3886 | ||
3887 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
3888 | driver->num); | |
ca509f69 | 3889 | mutex_lock(&tty_mutex); |
1da177e4 | 3890 | list_del(&driver->tty_drivers); |
ca509f69 | 3891 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
3892 | |
3893 | /* | |
3894 | * Free the termios and termios_locked structures because | |
3895 | * we don't want to get memory leaks when modular tty | |
3896 | * drivers are removed from the kernel. | |
3897 | */ | |
3898 | for (i = 0; i < driver->num; i++) { | |
3899 | tp = driver->termios[i]; | |
3900 | if (tp) { | |
3901 | driver->termios[i] = NULL; | |
3902 | kfree(tp); | |
3903 | } | |
3904 | tp = driver->termios_locked[i]; | |
3905 | if (tp) { | |
3906 | driver->termios_locked[i] = NULL; | |
3907 | kfree(tp); | |
3908 | } | |
331b8319 | 3909 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
1da177e4 LT |
3910 | tty_unregister_device(driver, i); |
3911 | } | |
3912 | p = driver->ttys; | |
3913 | proc_tty_unregister_driver(driver); | |
3914 | driver->ttys = NULL; | |
3915 | driver->termios = driver->termios_locked = NULL; | |
3916 | kfree(p); | |
3917 | cdev_del(&driver->cdev); | |
3918 | return 0; | |
3919 | } | |
1da177e4 LT |
3920 | EXPORT_SYMBOL(tty_unregister_driver); |
3921 | ||
24ec839c PZ |
3922 | dev_t tty_devnum(struct tty_struct *tty) |
3923 | { | |
3924 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
3925 | } | |
3926 | EXPORT_SYMBOL(tty_devnum); | |
3927 | ||
3928 | void proc_clear_tty(struct task_struct *p) | |
3929 | { | |
3930 | spin_lock_irq(&p->sighand->siglock); | |
3931 | p->signal->tty = NULL; | |
3932 | spin_unlock_irq(&p->sighand->siglock); | |
3933 | } | |
7cac4ce5 | 3934 | EXPORT_SYMBOL(proc_clear_tty); |
24ec839c | 3935 | |
2a65f1d9 | 3936 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
3937 | { |
3938 | if (tty) { | |
d9c1e9a8 EB |
3939 | /* We should not have a session or pgrp to here but.... */ |
3940 | put_pid(tty->session); | |
3941 | put_pid(tty->pgrp); | |
ab521dc0 EB |
3942 | tty->session = get_pid(task_session(tsk)); |
3943 | tty->pgrp = get_pid(task_pgrp(tsk)); | |
24ec839c | 3944 | } |
2a65f1d9 | 3945 | put_pid(tsk->signal->tty_old_pgrp); |
24ec839c | 3946 | tsk->signal->tty = tty; |
ab521dc0 | 3947 | tsk->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
3948 | } |
3949 | ||
98a27ba4 | 3950 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
3951 | { |
3952 | spin_lock_irq(&tsk->sighand->siglock); | |
2a65f1d9 | 3953 | __proc_set_tty(tsk, tty); |
24ec839c PZ |
3954 | spin_unlock_irq(&tsk->sighand->siglock); |
3955 | } | |
3956 | ||
3957 | struct tty_struct *get_current_tty(void) | |
3958 | { | |
3959 | struct tty_struct *tty; | |
3960 | WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); | |
3961 | tty = current->signal->tty; | |
3962 | /* | |
3963 | * session->tty can be changed/cleared from under us, make sure we | |
3964 | * issue the load. The obtained pointer, when not NULL, is valid as | |
3965 | * long as we hold tty_mutex. | |
3966 | */ | |
3967 | barrier(); | |
3968 | return tty; | |
3969 | } | |
a311f743 | 3970 | EXPORT_SYMBOL_GPL(get_current_tty); |
1da177e4 LT |
3971 | |
3972 | /* | |
3973 | * Initialize the console device. This is called *early*, so | |
3974 | * we can't necessarily depend on lots of kernel help here. | |
3975 | * Just do some early initializations, and do the complex setup | |
3976 | * later. | |
3977 | */ | |
3978 | void __init console_init(void) | |
3979 | { | |
3980 | initcall_t *call; | |
3981 | ||
3982 | /* Setup the default TTY line discipline. */ | |
3983 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); | |
3984 | ||
3985 | /* | |
3986 | * set up the console device so that later boot sequences can | |
3987 | * inform about problems etc.. | |
3988 | */ | |
1da177e4 LT |
3989 | call = __con_initcall_start; |
3990 | while (call < __con_initcall_end) { | |
3991 | (*call)(); | |
3992 | call++; | |
3993 | } | |
3994 | } | |
3995 | ||
3996 | #ifdef CONFIG_VT | |
3997 | extern int vty_init(void); | |
3998 | #endif | |
3999 | ||
4000 | static int __init tty_class_init(void) | |
4001 | { | |
7fe845d1 | 4002 | tty_class = class_create(THIS_MODULE, "tty"); |
1da177e4 LT |
4003 | if (IS_ERR(tty_class)) |
4004 | return PTR_ERR(tty_class); | |
4005 | return 0; | |
4006 | } | |
4007 | ||
4008 | postcore_initcall(tty_class_init); | |
4009 | ||
4010 | /* 3/2004 jmc: why do these devices exist? */ | |
4011 | ||
4012 | static struct cdev tty_cdev, console_cdev; | |
4013 | #ifdef CONFIG_UNIX98_PTYS | |
4014 | static struct cdev ptmx_cdev; | |
4015 | #endif | |
4016 | #ifdef CONFIG_VT | |
4017 | static struct cdev vc0_cdev; | |
4018 | #endif | |
4019 | ||
4020 | /* | |
4021 | * Ok, now we can initialize the rest of the tty devices and can count | |
4022 | * on memory allocations, interrupts etc.. | |
4023 | */ | |
4024 | static int __init tty_init(void) | |
4025 | { | |
4026 | cdev_init(&tty_cdev, &tty_fops); | |
4027 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
4028 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
4029 | panic("Couldn't register /dev/tty driver\n"); | |
01107d34 | 4030 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty"); |
1da177e4 LT |
4031 | |
4032 | cdev_init(&console_cdev, &console_fops); | |
4033 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
4034 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
4035 | panic("Couldn't register /dev/console driver\n"); | |
01107d34 | 4036 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console"); |
1da177e4 LT |
4037 | |
4038 | #ifdef CONFIG_UNIX98_PTYS | |
4039 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
4040 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
4041 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
4042 | panic("Couldn't register /dev/ptmx driver\n"); | |
01107d34 | 4043 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); |
1da177e4 LT |
4044 | #endif |
4045 | ||
4046 | #ifdef CONFIG_VT | |
4047 | cdev_init(&vc0_cdev, &console_fops); | |
4048 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || | |
4049 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) | |
4050 | panic("Couldn't register /dev/tty0 driver\n"); | |
01107d34 | 4051 | device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); |
1da177e4 LT |
4052 | |
4053 | vty_init(); | |
4054 | #endif | |
4055 | return 0; | |
4056 | } | |
4057 | module_init(tty_init); |