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 | ||
522ed776 MT |
1506 | /** |
1507 | * is_tty - checker whether file is a TTY | |
1508 | */ | |
1509 | int is_tty(struct file *filp) | |
1510 | { | |
1511 | return filp->f_op->read == tty_read | |
1512 | || filp->f_op->read == hung_up_tty_read; | |
1513 | } | |
1514 | ||
ab521dc0 | 1515 | static void session_clear_tty(struct pid *session) |
24ec839c PZ |
1516 | { |
1517 | struct task_struct *p; | |
ab521dc0 | 1518 | do_each_pid_task(session, PIDTYPE_SID, p) { |
24ec839c | 1519 | proc_clear_tty(p); |
ab521dc0 | 1520 | } while_each_pid_task(session, PIDTYPE_SID, p); |
24ec839c PZ |
1521 | } |
1522 | ||
af9b897e AC |
1523 | /** |
1524 | * disassociate_ctty - disconnect controlling tty | |
1525 | * @on_exit: true if exiting so need to "hang up" the session | |
1da177e4 | 1526 | * |
af9b897e AC |
1527 | * This function is typically called only by the session leader, when |
1528 | * it wants to disassociate itself from its controlling tty. | |
1529 | * | |
1530 | * It performs the following functions: | |
1da177e4 LT |
1531 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
1532 | * (2) Clears the tty from being controlling the session | |
1533 | * (3) Clears the controlling tty for all processes in the | |
1534 | * session group. | |
1535 | * | |
af9b897e AC |
1536 | * The argument on_exit is set to 1 if called when a process is |
1537 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. | |
1538 | * | |
24ec839c | 1539 | * Locking: |
af9b897e | 1540 | * BKL is taken for hysterical raisins |
24ec839c PZ |
1541 | * tty_mutex is taken to protect tty |
1542 | * ->siglock is taken to protect ->signal/->sighand | |
1543 | * tasklist_lock is taken to walk process list for sessions | |
1544 | * ->siglock is taken to protect ->signal/->sighand | |
1da177e4 | 1545 | */ |
af9b897e | 1546 | |
1da177e4 LT |
1547 | void disassociate_ctty(int on_exit) |
1548 | { | |
1549 | struct tty_struct *tty; | |
ab521dc0 | 1550 | struct pid *tty_pgrp = NULL; |
1da177e4 LT |
1551 | |
1552 | lock_kernel(); | |
1553 | ||
70522e12 | 1554 | mutex_lock(&tty_mutex); |
24ec839c | 1555 | tty = get_current_tty(); |
1da177e4 | 1556 | if (tty) { |
ab521dc0 | 1557 | tty_pgrp = get_pid(tty->pgrp); |
70522e12 | 1558 | mutex_unlock(&tty_mutex); |
24ec839c | 1559 | /* XXX: here we race, there is nothing protecting tty */ |
1da177e4 LT |
1560 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
1561 | tty_vhangup(tty); | |
680a9671 | 1562 | } else if (on_exit) { |
ab521dc0 | 1563 | struct pid *old_pgrp; |
680a9671 EB |
1564 | spin_lock_irq(¤t->sighand->siglock); |
1565 | old_pgrp = current->signal->tty_old_pgrp; | |
ab521dc0 | 1566 | current->signal->tty_old_pgrp = NULL; |
680a9671 | 1567 | spin_unlock_irq(¤t->sighand->siglock); |
24ec839c | 1568 | if (old_pgrp) { |
ab521dc0 EB |
1569 | kill_pgrp(old_pgrp, SIGHUP, on_exit); |
1570 | kill_pgrp(old_pgrp, SIGCONT, on_exit); | |
1571 | put_pid(old_pgrp); | |
1da177e4 | 1572 | } |
70522e12 | 1573 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
1574 | unlock_kernel(); |
1575 | return; | |
1576 | } | |
ab521dc0 EB |
1577 | if (tty_pgrp) { |
1578 | kill_pgrp(tty_pgrp, SIGHUP, on_exit); | |
1da177e4 | 1579 | if (!on_exit) |
ab521dc0 EB |
1580 | kill_pgrp(tty_pgrp, SIGCONT, on_exit); |
1581 | put_pid(tty_pgrp); | |
1da177e4 LT |
1582 | } |
1583 | ||
24ec839c | 1584 | spin_lock_irq(¤t->sighand->siglock); |
2a65f1d9 | 1585 | put_pid(current->signal->tty_old_pgrp); |
23cac8de | 1586 | current->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
1587 | spin_unlock_irq(¤t->sighand->siglock); |
1588 | ||
1589 | mutex_lock(&tty_mutex); | |
1590 | /* It is possible that do_tty_hangup has free'd this tty */ | |
1591 | tty = get_current_tty(); | |
1592 | if (tty) { | |
ab521dc0 EB |
1593 | put_pid(tty->session); |
1594 | put_pid(tty->pgrp); | |
1595 | tty->session = NULL; | |
1596 | tty->pgrp = NULL; | |
24ec839c PZ |
1597 | } else { |
1598 | #ifdef TTY_DEBUG_HANGUP | |
1599 | printk(KERN_DEBUG "error attempted to write to tty [0x%p]" | |
1600 | " = NULL", tty); | |
1601 | #endif | |
1602 | } | |
1603 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
1604 | |
1605 | /* Now clear signal->tty under the lock */ | |
1606 | read_lock(&tasklist_lock); | |
ab521dc0 | 1607 | session_clear_tty(task_session(current)); |
1da177e4 | 1608 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1609 | unlock_kernel(); |
1610 | } | |
1611 | ||
98a27ba4 EB |
1612 | /** |
1613 | * | |
1614 | * no_tty - Ensure the current process does not have a controlling tty | |
1615 | */ | |
1616 | void no_tty(void) | |
1617 | { | |
1618 | struct task_struct *tsk = current; | |
1619 | if (tsk->signal->leader) | |
1620 | disassociate_ctty(0); | |
1621 | proc_clear_tty(tsk); | |
1622 | } | |
1623 | ||
af9b897e AC |
1624 | |
1625 | /** | |
beb7dd86 | 1626 | * stop_tty - propagate flow control |
af9b897e AC |
1627 | * @tty: tty to stop |
1628 | * | |
1629 | * Perform flow control to the driver. For PTY/TTY pairs we | |
beb7dd86 | 1630 | * must also propagate the TIOCKPKT status. May be called |
af9b897e AC |
1631 | * on an already stopped device and will not re-call the driver |
1632 | * method. | |
1633 | * | |
1634 | * This functionality is used by both the line disciplines for | |
1635 | * halting incoming flow and by the driver. It may therefore be | |
1636 | * called from any context, may be under the tty atomic_write_lock | |
1637 | * but not always. | |
1638 | * | |
1639 | * Locking: | |
1640 | * Broken. Relies on BKL which is unsafe here. | |
1641 | */ | |
1642 | ||
1da177e4 LT |
1643 | void stop_tty(struct tty_struct *tty) |
1644 | { | |
1645 | if (tty->stopped) | |
1646 | return; | |
1647 | tty->stopped = 1; | |
1648 | if (tty->link && tty->link->packet) { | |
1649 | tty->ctrl_status &= ~TIOCPKT_START; | |
1650 | tty->ctrl_status |= TIOCPKT_STOP; | |
1651 | wake_up_interruptible(&tty->link->read_wait); | |
1652 | } | |
1653 | if (tty->driver->stop) | |
1654 | (tty->driver->stop)(tty); | |
1655 | } | |
1656 | ||
1657 | EXPORT_SYMBOL(stop_tty); | |
1658 | ||
af9b897e | 1659 | /** |
beb7dd86 | 1660 | * start_tty - propagate flow control |
af9b897e AC |
1661 | * @tty: tty to start |
1662 | * | |
1663 | * Start a tty that has been stopped if at all possible. Perform | |
beb7dd86 | 1664 | * any neccessary wakeups and propagate the TIOCPKT status. If this |
af9b897e AC |
1665 | * is the tty was previous stopped and is being started then the |
1666 | * driver start method is invoked and the line discipline woken. | |
1667 | * | |
1668 | * Locking: | |
1669 | * Broken. Relies on BKL which is unsafe here. | |
1670 | */ | |
1671 | ||
1da177e4 LT |
1672 | void start_tty(struct tty_struct *tty) |
1673 | { | |
1674 | if (!tty->stopped || tty->flow_stopped) | |
1675 | return; | |
1676 | tty->stopped = 0; | |
1677 | if (tty->link && tty->link->packet) { | |
1678 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
1679 | tty->ctrl_status |= TIOCPKT_START; | |
1680 | wake_up_interruptible(&tty->link->read_wait); | |
1681 | } | |
1682 | if (tty->driver->start) | |
1683 | (tty->driver->start)(tty); | |
1684 | ||
1685 | /* If we have a running line discipline it may need kicking */ | |
1686 | tty_wakeup(tty); | |
1da177e4 LT |
1687 | } |
1688 | ||
1689 | EXPORT_SYMBOL(start_tty); | |
1690 | ||
af9b897e AC |
1691 | /** |
1692 | * tty_read - read method for tty device files | |
1693 | * @file: pointer to tty file | |
1694 | * @buf: user buffer | |
1695 | * @count: size of user buffer | |
1696 | * @ppos: unused | |
1697 | * | |
1698 | * Perform the read system call function on this terminal device. Checks | |
1699 | * for hung up devices before calling the line discipline method. | |
1700 | * | |
1701 | * Locking: | |
1702 | * Locks the line discipline internally while needed | |
1703 | * For historical reasons the line discipline read method is | |
1704 | * invoked under the BKL. This will go away in time so do not rely on it | |
1705 | * in new code. Multiple read calls may be outstanding in parallel. | |
1706 | */ | |
1707 | ||
1da177e4 LT |
1708 | static ssize_t tty_read(struct file * file, char __user * buf, size_t count, |
1709 | loff_t *ppos) | |
1710 | { | |
1711 | int i; | |
1712 | struct tty_struct * tty; | |
1713 | struct inode *inode; | |
1714 | struct tty_ldisc *ld; | |
1715 | ||
1716 | tty = (struct tty_struct *)file->private_data; | |
a7113a96 | 1717 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1718 | if (tty_paranoia_check(tty, inode, "tty_read")) |
1719 | return -EIO; | |
1720 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1721 | return -EIO; | |
1722 | ||
1723 | /* We want to wait for the line discipline to sort out in this | |
1724 | situation */ | |
1725 | ld = tty_ldisc_ref_wait(tty); | |
1726 | lock_kernel(); | |
1727 | if (ld->read) | |
1728 | i = (ld->read)(tty,file,buf,count); | |
1729 | else | |
1730 | i = -EIO; | |
1731 | tty_ldisc_deref(ld); | |
1732 | unlock_kernel(); | |
1733 | if (i > 0) | |
1734 | inode->i_atime = current_fs_time(inode->i_sb); | |
1735 | return i; | |
1736 | } | |
1737 | ||
9c1729db AC |
1738 | void tty_write_unlock(struct tty_struct *tty) |
1739 | { | |
1740 | mutex_unlock(&tty->atomic_write_lock); | |
1741 | wake_up_interruptible(&tty->write_wait); | |
1742 | } | |
1743 | ||
1744 | int tty_write_lock(struct tty_struct *tty, int ndelay) | |
1745 | { | |
1746 | if (!mutex_trylock(&tty->atomic_write_lock)) { | |
1747 | if (ndelay) | |
1748 | return -EAGAIN; | |
1749 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) | |
1750 | return -ERESTARTSYS; | |
1751 | } | |
1752 | return 0; | |
1753 | } | |
1754 | ||
1da177e4 LT |
1755 | /* |
1756 | * Split writes up in sane blocksizes to avoid | |
1757 | * denial-of-service type attacks | |
1758 | */ | |
1759 | static inline ssize_t do_tty_write( | |
1760 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
1761 | struct tty_struct *tty, | |
1762 | struct file *file, | |
1763 | const char __user *buf, | |
1764 | size_t count) | |
1765 | { | |
9c1729db | 1766 | ssize_t ret, written = 0; |
1da177e4 LT |
1767 | unsigned int chunk; |
1768 | ||
9c1729db AC |
1769 | ret = tty_write_lock(tty, file->f_flags & O_NDELAY); |
1770 | if (ret < 0) | |
1771 | return ret; | |
1da177e4 LT |
1772 | |
1773 | /* | |
1774 | * We chunk up writes into a temporary buffer. This | |
1775 | * simplifies low-level drivers immensely, since they | |
1776 | * don't have locking issues and user mode accesses. | |
1777 | * | |
1778 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
1779 | * big chunk-size.. | |
1780 | * | |
1781 | * The default chunk-size is 2kB, because the NTTY | |
1782 | * layer has problems with bigger chunks. It will | |
1783 | * claim to be able to handle more characters than | |
1784 | * it actually does. | |
af9b897e AC |
1785 | * |
1786 | * FIXME: This can probably go away now except that 64K chunks | |
1787 | * are too likely to fail unless switched to vmalloc... | |
1da177e4 LT |
1788 | */ |
1789 | chunk = 2048; | |
1790 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
1791 | chunk = 65536; | |
1792 | if (count < chunk) | |
1793 | chunk = count; | |
1794 | ||
70522e12 | 1795 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
1da177e4 LT |
1796 | if (tty->write_cnt < chunk) { |
1797 | unsigned char *buf; | |
1798 | ||
1799 | if (chunk < 1024) | |
1800 | chunk = 1024; | |
1801 | ||
1802 | buf = kmalloc(chunk, GFP_KERNEL); | |
1803 | if (!buf) { | |
9c1729db AC |
1804 | ret = -ENOMEM; |
1805 | goto out; | |
1da177e4 LT |
1806 | } |
1807 | kfree(tty->write_buf); | |
1808 | tty->write_cnt = chunk; | |
1809 | tty->write_buf = buf; | |
1810 | } | |
1811 | ||
1812 | /* Do the write .. */ | |
1813 | for (;;) { | |
1814 | size_t size = count; | |
1815 | if (size > chunk) | |
1816 | size = chunk; | |
1817 | ret = -EFAULT; | |
1818 | if (copy_from_user(tty->write_buf, buf, size)) | |
1819 | break; | |
1820 | lock_kernel(); | |
1821 | ret = write(tty, file, tty->write_buf, size); | |
1822 | unlock_kernel(); | |
1823 | if (ret <= 0) | |
1824 | break; | |
1825 | written += ret; | |
1826 | buf += ret; | |
1827 | count -= ret; | |
1828 | if (!count) | |
1829 | break; | |
1830 | ret = -ERESTARTSYS; | |
1831 | if (signal_pending(current)) | |
1832 | break; | |
1833 | cond_resched(); | |
1834 | } | |
1835 | if (written) { | |
a7113a96 | 1836 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1837 | inode->i_mtime = current_fs_time(inode->i_sb); |
1838 | ret = written; | |
1839 | } | |
9c1729db AC |
1840 | out: |
1841 | tty_write_unlock(tty); | |
1da177e4 LT |
1842 | return ret; |
1843 | } | |
1844 | ||
1845 | ||
af9b897e AC |
1846 | /** |
1847 | * tty_write - write method for tty device file | |
1848 | * @file: tty file pointer | |
1849 | * @buf: user data to write | |
1850 | * @count: bytes to write | |
1851 | * @ppos: unused | |
1852 | * | |
1853 | * Write data to a tty device via the line discipline. | |
1854 | * | |
1855 | * Locking: | |
1856 | * Locks the line discipline as required | |
1857 | * Writes to the tty driver are serialized by the atomic_write_lock | |
1858 | * and are then processed in chunks to the device. The line discipline | |
1859 | * write method will not be involked in parallel for each device | |
1860 | * The line discipline write method is called under the big | |
1861 | * kernel lock for historical reasons. New code should not rely on this. | |
1862 | */ | |
1863 | ||
1da177e4 LT |
1864 | static ssize_t tty_write(struct file * file, const char __user * buf, size_t count, |
1865 | loff_t *ppos) | |
1866 | { | |
1867 | struct tty_struct * tty; | |
a7113a96 | 1868 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1869 | ssize_t ret; |
1870 | struct tty_ldisc *ld; | |
1871 | ||
1872 | tty = (struct tty_struct *)file->private_data; | |
1873 | if (tty_paranoia_check(tty, inode, "tty_write")) | |
1874 | return -EIO; | |
1875 | if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1876 | return -EIO; | |
1877 | ||
1878 | ld = tty_ldisc_ref_wait(tty); | |
1879 | if (!ld->write) | |
1880 | ret = -EIO; | |
1881 | else | |
1882 | ret = do_tty_write(ld->write, tty, file, buf, count); | |
1883 | tty_ldisc_deref(ld); | |
1884 | return ret; | |
1885 | } | |
1886 | ||
1887 | ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count, | |
1888 | loff_t *ppos) | |
1889 | { | |
1890 | struct file *p = NULL; | |
1891 | ||
1892 | spin_lock(&redirect_lock); | |
1893 | if (redirect) { | |
1894 | get_file(redirect); | |
1895 | p = redirect; | |
1896 | } | |
1897 | spin_unlock(&redirect_lock); | |
1898 | ||
1899 | if (p) { | |
1900 | ssize_t res; | |
1901 | res = vfs_write(p, buf, count, &p->f_pos); | |
1902 | fput(p); | |
1903 | return res; | |
1904 | } | |
1905 | ||
1906 | return tty_write(file, buf, count, ppos); | |
1907 | } | |
1908 | ||
1909 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
1910 | ||
af9b897e AC |
1911 | /** |
1912 | * pty_line_name - generate name for a pty | |
1913 | * @driver: the tty driver in use | |
1914 | * @index: the minor number | |
1915 | * @p: output buffer of at least 6 bytes | |
1916 | * | |
1917 | * Generate a name from a driver reference and write it to the output | |
1918 | * buffer. | |
1919 | * | |
1920 | * Locking: None | |
1921 | */ | |
1922 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1923 | { |
1924 | int i = index + driver->name_base; | |
1925 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
1926 | sprintf(p, "%s%c%x", | |
1927 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, | |
1928 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1929 | } | |
1930 | ||
af9b897e AC |
1931 | /** |
1932 | * pty_line_name - generate name for a tty | |
1933 | * @driver: the tty driver in use | |
1934 | * @index: the minor number | |
1935 | * @p: output buffer of at least 7 bytes | |
1936 | * | |
1937 | * Generate a name from a driver reference and write it to the output | |
1938 | * buffer. | |
1939 | * | |
1940 | * Locking: None | |
1941 | */ | |
1942 | static void tty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
1943 | { |
1944 | sprintf(p, "%s%d", driver->name, index + driver->name_base); | |
1945 | } | |
1946 | ||
af9b897e AC |
1947 | /** |
1948 | * init_dev - initialise a tty device | |
1949 | * @driver: tty driver we are opening a device on | |
1950 | * @idx: device index | |
1951 | * @tty: returned tty structure | |
1952 | * | |
1953 | * Prepare a tty device. This may not be a "new" clean device but | |
1954 | * could also be an active device. The pty drivers require special | |
1955 | * handling because of this. | |
1956 | * | |
1957 | * Locking: | |
1958 | * The function is called under the tty_mutex, which | |
1959 | * protects us from the tty struct or driver itself going away. | |
1960 | * | |
1961 | * On exit the tty device has the line discipline attached and | |
1962 | * a reference count of 1. If a pair was created for pty/tty use | |
1963 | * and the other was a pty master then it too has a reference count of 1. | |
1964 | * | |
1da177e4 | 1965 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
70522e12 IM |
1966 | * failed open. The new code protects the open with a mutex, so it's |
1967 | * really quite straightforward. The mutex locking can probably be | |
1da177e4 LT |
1968 | * relaxed for the (most common) case of reopening a tty. |
1969 | */ | |
af9b897e | 1970 | |
1da177e4 LT |
1971 | static int init_dev(struct tty_driver *driver, int idx, |
1972 | struct tty_struct **ret_tty) | |
1973 | { | |
1974 | struct tty_struct *tty, *o_tty; | |
edc6afc5 AC |
1975 | struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; |
1976 | struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; | |
af9b897e | 1977 | int retval = 0; |
1da177e4 LT |
1978 | |
1979 | /* check whether we're reopening an existing tty */ | |
1980 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
1981 | tty = devpts_get_tty(idx); | |
5a39e8c6 ASRF |
1982 | /* |
1983 | * If we don't have a tty here on a slave open, it's because | |
1984 | * the master already started the close process and there's | |
1985 | * no relation between devpts file and tty anymore. | |
1986 | */ | |
1987 | if (!tty && driver->subtype == PTY_TYPE_SLAVE) { | |
1988 | retval = -EIO; | |
1989 | goto end_init; | |
1990 | } | |
1991 | /* | |
1992 | * It's safe from now on because init_dev() is called with | |
1993 | * tty_mutex held and release_dev() won't change tty->count | |
1994 | * or tty->flags without having to grab tty_mutex | |
1995 | */ | |
1da177e4 LT |
1996 | if (tty && driver->subtype == PTY_TYPE_MASTER) |
1997 | tty = tty->link; | |
1998 | } else { | |
1999 | tty = driver->ttys[idx]; | |
2000 | } | |
2001 | if (tty) goto fast_track; | |
2002 | ||
2003 | /* | |
2004 | * First time open is complex, especially for PTY devices. | |
2005 | * This code guarantees that either everything succeeds and the | |
2006 | * TTY is ready for operation, or else the table slots are vacated | |
2007 | * and the allocated memory released. (Except that the termios | |
2008 | * and locked termios may be retained.) | |
2009 | */ | |
2010 | ||
2011 | if (!try_module_get(driver->owner)) { | |
2012 | retval = -ENODEV; | |
2013 | goto end_init; | |
2014 | } | |
2015 | ||
2016 | o_tty = NULL; | |
2017 | tp = o_tp = NULL; | |
2018 | ltp = o_ltp = NULL; | |
2019 | ||
2020 | tty = alloc_tty_struct(); | |
2021 | if(!tty) | |
2022 | goto fail_no_mem; | |
2023 | initialize_tty_struct(tty); | |
2024 | tty->driver = driver; | |
2025 | tty->index = idx; | |
2026 | tty_line_name(driver, idx, tty->name); | |
2027 | ||
2028 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2029 | tp_loc = &tty->termios; | |
2030 | ltp_loc = &tty->termios_locked; | |
2031 | } else { | |
2032 | tp_loc = &driver->termios[idx]; | |
2033 | ltp_loc = &driver->termios_locked[idx]; | |
2034 | } | |
2035 | ||
2036 | if (!*tp_loc) { | |
edc6afc5 | 2037 | tp = (struct ktermios *) kmalloc(sizeof(struct ktermios), |
1da177e4 LT |
2038 | GFP_KERNEL); |
2039 | if (!tp) | |
2040 | goto free_mem_out; | |
2041 | *tp = driver->init_termios; | |
2042 | } | |
2043 | ||
2044 | if (!*ltp_loc) { | |
506eb99a | 2045 | ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2046 | if (!ltp) |
2047 | goto free_mem_out; | |
1da177e4 LT |
2048 | } |
2049 | ||
2050 | if (driver->type == TTY_DRIVER_TYPE_PTY) { | |
2051 | o_tty = alloc_tty_struct(); | |
2052 | if (!o_tty) | |
2053 | goto free_mem_out; | |
2054 | initialize_tty_struct(o_tty); | |
2055 | o_tty->driver = driver->other; | |
2056 | o_tty->index = idx; | |
2057 | tty_line_name(driver->other, idx, o_tty->name); | |
2058 | ||
2059 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2060 | o_tp_loc = &o_tty->termios; | |
2061 | o_ltp_loc = &o_tty->termios_locked; | |
2062 | } else { | |
2063 | o_tp_loc = &driver->other->termios[idx]; | |
2064 | o_ltp_loc = &driver->other->termios_locked[idx]; | |
2065 | } | |
2066 | ||
2067 | if (!*o_tp_loc) { | |
edc6afc5 AC |
2068 | o_tp = (struct ktermios *) |
2069 | kmalloc(sizeof(struct ktermios), GFP_KERNEL); | |
1da177e4 LT |
2070 | if (!o_tp) |
2071 | goto free_mem_out; | |
2072 | *o_tp = driver->other->init_termios; | |
2073 | } | |
2074 | ||
2075 | if (!*o_ltp_loc) { | |
506eb99a | 2076 | o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2077 | if (!o_ltp) |
2078 | goto free_mem_out; | |
1da177e4 LT |
2079 | } |
2080 | ||
2081 | /* | |
2082 | * Everything allocated ... set up the o_tty structure. | |
2083 | */ | |
2084 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2085 | driver->other->ttys[idx] = o_tty; | |
2086 | } | |
2087 | if (!*o_tp_loc) | |
2088 | *o_tp_loc = o_tp; | |
2089 | if (!*o_ltp_loc) | |
2090 | *o_ltp_loc = o_ltp; | |
2091 | o_tty->termios = *o_tp_loc; | |
2092 | o_tty->termios_locked = *o_ltp_loc; | |
2093 | driver->other->refcount++; | |
2094 | if (driver->subtype == PTY_TYPE_MASTER) | |
2095 | o_tty->count++; | |
2096 | ||
2097 | /* Establish the links in both directions */ | |
2098 | tty->link = o_tty; | |
2099 | o_tty->link = tty; | |
2100 | } | |
2101 | ||
2102 | /* | |
2103 | * All structures have been allocated, so now we install them. | |
d5698c28 | 2104 | * Failures after this point use release_tty to clean up, so |
1da177e4 LT |
2105 | * there's no need to null out the local pointers. |
2106 | */ | |
2107 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2108 | driver->ttys[idx] = tty; | |
2109 | } | |
2110 | ||
2111 | if (!*tp_loc) | |
2112 | *tp_loc = tp; | |
2113 | if (!*ltp_loc) | |
2114 | *ltp_loc = ltp; | |
2115 | tty->termios = *tp_loc; | |
2116 | tty->termios_locked = *ltp_loc; | |
edc6afc5 AC |
2117 | /* Compatibility until drivers always set this */ |
2118 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
2119 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1da177e4 LT |
2120 | driver->refcount++; |
2121 | tty->count++; | |
2122 | ||
2123 | /* | |
2124 | * Structures all installed ... call the ldisc open routines. | |
d5698c28 CH |
2125 | * If we fail here just call release_tty to clean up. No need |
2126 | * to decrement the use counts, as release_tty doesn't care. | |
1da177e4 LT |
2127 | */ |
2128 | ||
2129 | if (tty->ldisc.open) { | |
2130 | retval = (tty->ldisc.open)(tty); | |
2131 | if (retval) | |
2132 | goto release_mem_out; | |
2133 | } | |
2134 | if (o_tty && o_tty->ldisc.open) { | |
2135 | retval = (o_tty->ldisc.open)(o_tty); | |
2136 | if (retval) { | |
2137 | if (tty->ldisc.close) | |
2138 | (tty->ldisc.close)(tty); | |
2139 | goto release_mem_out; | |
2140 | } | |
2141 | tty_ldisc_enable(o_tty); | |
2142 | } | |
2143 | tty_ldisc_enable(tty); | |
2144 | goto success; | |
2145 | ||
2146 | /* | |
2147 | * This fast open can be used if the tty is already open. | |
2148 | * No memory is allocated, and the only failures are from | |
2149 | * attempting to open a closing tty or attempting multiple | |
2150 | * opens on a pty master. | |
2151 | */ | |
2152 | fast_track: | |
2153 | if (test_bit(TTY_CLOSING, &tty->flags)) { | |
2154 | retval = -EIO; | |
2155 | goto end_init; | |
2156 | } | |
2157 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
2158 | driver->subtype == PTY_TYPE_MASTER) { | |
2159 | /* | |
2160 | * special case for PTY masters: only one open permitted, | |
2161 | * and the slave side open count is incremented as well. | |
2162 | */ | |
2163 | if (tty->count) { | |
2164 | retval = -EIO; | |
2165 | goto end_init; | |
2166 | } | |
2167 | tty->link->count++; | |
2168 | } | |
2169 | tty->count++; | |
2170 | tty->driver = driver; /* N.B. why do this every time?? */ | |
2171 | ||
2172 | /* FIXME */ | |
2173 | if(!test_bit(TTY_LDISC, &tty->flags)) | |
2174 | printk(KERN_ERR "init_dev but no ldisc\n"); | |
2175 | success: | |
2176 | *ret_tty = tty; | |
2177 | ||
70522e12 | 2178 | /* All paths come through here to release the mutex */ |
1da177e4 LT |
2179 | end_init: |
2180 | return retval; | |
2181 | ||
2182 | /* Release locally allocated memory ... nothing placed in slots */ | |
2183 | free_mem_out: | |
735d5661 | 2184 | kfree(o_tp); |
1da177e4 LT |
2185 | if (o_tty) |
2186 | free_tty_struct(o_tty); | |
735d5661 JJ |
2187 | kfree(ltp); |
2188 | kfree(tp); | |
1da177e4 LT |
2189 | free_tty_struct(tty); |
2190 | ||
2191 | fail_no_mem: | |
2192 | module_put(driver->owner); | |
2193 | retval = -ENOMEM; | |
2194 | goto end_init; | |
2195 | ||
d5698c28 | 2196 | /* call the tty release_tty routine to clean out this slot */ |
1da177e4 | 2197 | release_mem_out: |
4050914f AM |
2198 | if (printk_ratelimit()) |
2199 | printk(KERN_INFO "init_dev: ldisc open failed, " | |
2200 | "clearing slot %d\n", idx); | |
d5698c28 | 2201 | release_tty(tty, idx); |
1da177e4 LT |
2202 | goto end_init; |
2203 | } | |
2204 | ||
af9b897e | 2205 | /** |
d5698c28 | 2206 | * release_one_tty - release tty structure memory |
af9b897e AC |
2207 | * |
2208 | * Releases memory associated with a tty structure, and clears out the | |
2209 | * driver table slots. This function is called when a device is no longer | |
2210 | * in use. It also gets called when setup of a device fails. | |
2211 | * | |
2212 | * Locking: | |
2213 | * tty_mutex - sometimes only | |
2214 | * takes the file list lock internally when working on the list | |
2215 | * of ttys that the driver keeps. | |
2216 | * FIXME: should we require tty_mutex is held here ?? | |
1da177e4 | 2217 | */ |
d5698c28 | 2218 | static void release_one_tty(struct tty_struct *tty, int idx) |
1da177e4 | 2219 | { |
1da177e4 | 2220 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
d5698c28 | 2221 | struct ktermios *tp; |
1da177e4 LT |
2222 | |
2223 | if (!devpts) | |
2224 | tty->driver->ttys[idx] = NULL; | |
d5698c28 | 2225 | |
1da177e4 LT |
2226 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
2227 | tp = tty->termios; | |
2228 | if (!devpts) | |
2229 | tty->driver->termios[idx] = NULL; | |
2230 | kfree(tp); | |
2231 | ||
2232 | tp = tty->termios_locked; | |
2233 | if (!devpts) | |
2234 | tty->driver->termios_locked[idx] = NULL; | |
2235 | kfree(tp); | |
2236 | } | |
2237 | ||
d5698c28 | 2238 | |
1da177e4 LT |
2239 | tty->magic = 0; |
2240 | tty->driver->refcount--; | |
d5698c28 | 2241 | |
1da177e4 LT |
2242 | file_list_lock(); |
2243 | list_del_init(&tty->tty_files); | |
2244 | file_list_unlock(); | |
d5698c28 | 2245 | |
1da177e4 LT |
2246 | free_tty_struct(tty); |
2247 | } | |
2248 | ||
d5698c28 CH |
2249 | /** |
2250 | * release_tty - release tty structure memory | |
2251 | * | |
2252 | * Release both @tty and a possible linked partner (think pty pair), | |
2253 | * and decrement the refcount of the backing module. | |
2254 | * | |
2255 | * Locking: | |
2256 | * tty_mutex - sometimes only | |
2257 | * takes the file list lock internally when working on the list | |
2258 | * of ttys that the driver keeps. | |
2259 | * FIXME: should we require tty_mutex is held here ?? | |
2260 | */ | |
2261 | static void release_tty(struct tty_struct *tty, int idx) | |
2262 | { | |
2263 | struct tty_driver *driver = tty->driver; | |
2264 | ||
2265 | if (tty->link) | |
2266 | release_one_tty(tty->link, idx); | |
2267 | release_one_tty(tty, idx); | |
2268 | module_put(driver->owner); | |
2269 | } | |
2270 | ||
1da177e4 LT |
2271 | /* |
2272 | * Even releasing the tty structures is a tricky business.. We have | |
2273 | * to be very careful that the structures are all released at the | |
2274 | * same time, as interrupts might otherwise get the wrong pointers. | |
2275 | * | |
2276 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
2277 | * lead to double frees or releasing memory still in use. | |
2278 | */ | |
2279 | static void release_dev(struct file * filp) | |
2280 | { | |
2281 | struct tty_struct *tty, *o_tty; | |
2282 | int pty_master, tty_closing, o_tty_closing, do_sleep; | |
14a6283e | 2283 | int devpts; |
1da177e4 LT |
2284 | int idx; |
2285 | char buf[64]; | |
2286 | unsigned long flags; | |
2287 | ||
2288 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2289 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "release_dev")) |
1da177e4 LT |
2290 | return; |
2291 | ||
2292 | check_tty_count(tty, "release_dev"); | |
2293 | ||
2294 | tty_fasync(-1, filp, 0); | |
2295 | ||
2296 | idx = tty->index; | |
2297 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2298 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2299 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; | |
1da177e4 LT |
2300 | o_tty = tty->link; |
2301 | ||
2302 | #ifdef TTY_PARANOIA_CHECK | |
2303 | if (idx < 0 || idx >= tty->driver->num) { | |
2304 | printk(KERN_DEBUG "release_dev: bad idx when trying to " | |
2305 | "free (%s)\n", tty->name); | |
2306 | return; | |
2307 | } | |
2308 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2309 | if (tty != tty->driver->ttys[idx]) { | |
2310 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " | |
2311 | "for (%s)\n", idx, tty->name); | |
2312 | return; | |
2313 | } | |
2314 | if (tty->termios != tty->driver->termios[idx]) { | |
2315 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " | |
2316 | "for (%s)\n", | |
2317 | idx, tty->name); | |
2318 | return; | |
2319 | } | |
2320 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { | |
2321 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " | |
2322 | "termios_locked for (%s)\n", | |
2323 | idx, tty->name); | |
2324 | return; | |
2325 | } | |
2326 | } | |
2327 | #endif | |
2328 | ||
2329 | #ifdef TTY_DEBUG_HANGUP | |
2330 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", | |
2331 | tty_name(tty, buf), tty->count); | |
2332 | #endif | |
2333 | ||
2334 | #ifdef TTY_PARANOIA_CHECK | |
2335 | if (tty->driver->other && | |
2336 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2337 | if (o_tty != tty->driver->other->ttys[idx]) { | |
2338 | printk(KERN_DEBUG "release_dev: other->table[%d] " | |
2339 | "not o_tty for (%s)\n", | |
2340 | idx, tty->name); | |
2341 | return; | |
2342 | } | |
2343 | if (o_tty->termios != tty->driver->other->termios[idx]) { | |
2344 | printk(KERN_DEBUG "release_dev: other->termios[%d] " | |
2345 | "not o_termios for (%s)\n", | |
2346 | idx, tty->name); | |
2347 | return; | |
2348 | } | |
2349 | if (o_tty->termios_locked != | |
2350 | tty->driver->other->termios_locked[idx]) { | |
2351 | printk(KERN_DEBUG "release_dev: other->termios_locked[" | |
2352 | "%d] not o_termios_locked for (%s)\n", | |
2353 | idx, tty->name); | |
2354 | return; | |
2355 | } | |
2356 | if (o_tty->link != tty) { | |
2357 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); | |
2358 | return; | |
2359 | } | |
2360 | } | |
2361 | #endif | |
2362 | if (tty->driver->close) | |
2363 | tty->driver->close(tty, filp); | |
2364 | ||
2365 | /* | |
2366 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
2367 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
2368 | * wait queues and kick everyone out _before_ actually starting to | |
2369 | * close. This ensures that we won't block while releasing the tty | |
2370 | * structure. | |
2371 | * | |
2372 | * The test for the o_tty closing is necessary, since the master and | |
2373 | * slave sides may close in any order. If the slave side closes out | |
2374 | * first, its count will be one, since the master side holds an open. | |
2375 | * Thus this test wouldn't be triggered at the time the slave closes, | |
2376 | * so we do it now. | |
2377 | * | |
2378 | * Note that it's possible for the tty to be opened again while we're | |
2379 | * flushing out waiters. By recalculating the closing flags before | |
2380 | * each iteration we avoid any problems. | |
2381 | */ | |
2382 | while (1) { | |
2383 | /* Guard against races with tty->count changes elsewhere and | |
2384 | opens on /dev/tty */ | |
2385 | ||
70522e12 | 2386 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2387 | tty_closing = tty->count <= 1; |
2388 | o_tty_closing = o_tty && | |
2389 | (o_tty->count <= (pty_master ? 1 : 0)); | |
1da177e4 LT |
2390 | do_sleep = 0; |
2391 | ||
2392 | if (tty_closing) { | |
2393 | if (waitqueue_active(&tty->read_wait)) { | |
2394 | wake_up(&tty->read_wait); | |
2395 | do_sleep++; | |
2396 | } | |
2397 | if (waitqueue_active(&tty->write_wait)) { | |
2398 | wake_up(&tty->write_wait); | |
2399 | do_sleep++; | |
2400 | } | |
2401 | } | |
2402 | if (o_tty_closing) { | |
2403 | if (waitqueue_active(&o_tty->read_wait)) { | |
2404 | wake_up(&o_tty->read_wait); | |
2405 | do_sleep++; | |
2406 | } | |
2407 | if (waitqueue_active(&o_tty->write_wait)) { | |
2408 | wake_up(&o_tty->write_wait); | |
2409 | do_sleep++; | |
2410 | } | |
2411 | } | |
2412 | if (!do_sleep) | |
2413 | break; | |
2414 | ||
2415 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " | |
2416 | "active!\n", tty_name(tty, buf)); | |
70522e12 | 2417 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2418 | schedule(); |
2419 | } | |
2420 | ||
2421 | /* | |
2422 | * The closing flags are now consistent with the open counts on | |
2423 | * both sides, and we've completed the last operation that could | |
2424 | * block, so it's safe to proceed with closing. | |
2425 | */ | |
1da177e4 LT |
2426 | if (pty_master) { |
2427 | if (--o_tty->count < 0) { | |
2428 | printk(KERN_WARNING "release_dev: bad pty slave count " | |
2429 | "(%d) for %s\n", | |
2430 | o_tty->count, tty_name(o_tty, buf)); | |
2431 | o_tty->count = 0; | |
2432 | } | |
2433 | } | |
2434 | if (--tty->count < 0) { | |
2435 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", | |
2436 | tty->count, tty_name(tty, buf)); | |
2437 | tty->count = 0; | |
2438 | } | |
1da177e4 LT |
2439 | |
2440 | /* | |
2441 | * We've decremented tty->count, so we need to remove this file | |
2442 | * descriptor off the tty->tty_files list; this serves two | |
2443 | * purposes: | |
2444 | * - check_tty_count sees the correct number of file descriptors | |
2445 | * associated with this tty. | |
2446 | * - do_tty_hangup no longer sees this file descriptor as | |
2447 | * something that needs to be handled for hangups. | |
2448 | */ | |
2449 | file_kill(filp); | |
2450 | filp->private_data = NULL; | |
2451 | ||
2452 | /* | |
2453 | * Perform some housekeeping before deciding whether to return. | |
2454 | * | |
2455 | * Set the TTY_CLOSING flag if this was the last open. In the | |
2456 | * case of a pty we may have to wait around for the other side | |
2457 | * to close, and TTY_CLOSING makes sure we can't be reopened. | |
2458 | */ | |
2459 | if(tty_closing) | |
2460 | set_bit(TTY_CLOSING, &tty->flags); | |
2461 | if(o_tty_closing) | |
2462 | set_bit(TTY_CLOSING, &o_tty->flags); | |
2463 | ||
2464 | /* | |
2465 | * If _either_ side is closing, make sure there aren't any | |
2466 | * processes that still think tty or o_tty is their controlling | |
2467 | * tty. | |
2468 | */ | |
2469 | if (tty_closing || o_tty_closing) { | |
1da177e4 | 2470 | read_lock(&tasklist_lock); |
24ec839c | 2471 | session_clear_tty(tty->session); |
1da177e4 | 2472 | if (o_tty) |
24ec839c | 2473 | session_clear_tty(o_tty->session); |
1da177e4 LT |
2474 | read_unlock(&tasklist_lock); |
2475 | } | |
2476 | ||
70522e12 | 2477 | mutex_unlock(&tty_mutex); |
da965822 | 2478 | |
1da177e4 LT |
2479 | /* check whether both sides are closing ... */ |
2480 | if (!tty_closing || (o_tty && !o_tty_closing)) | |
2481 | return; | |
2482 | ||
2483 | #ifdef TTY_DEBUG_HANGUP | |
2484 | printk(KERN_DEBUG "freeing tty structure..."); | |
2485 | #endif | |
2486 | /* | |
2487 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then | |
2488 | * kill any delayed work. As this is the final close it does not | |
2489 | * race with the set_ldisc code path. | |
2490 | */ | |
2491 | clear_bit(TTY_LDISC, &tty->flags); | |
33f0f88f | 2492 | cancel_delayed_work(&tty->buf.work); |
1da177e4 LT |
2493 | |
2494 | /* | |
33f0f88f | 2495 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 LT |
2496 | */ |
2497 | ||
2498 | flush_scheduled_work(); | |
2499 | ||
2500 | /* | |
2501 | * Wait for any short term users (we know they are just driver | |
2502 | * side waiters as the file is closing so user count on the file | |
2503 | * side is zero. | |
2504 | */ | |
2505 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2506 | while(tty->ldisc.refcount) | |
2507 | { | |
2508 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2509 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); | |
2510 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2511 | } | |
2512 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2513 | /* | |
2514 | * Shutdown the current line discipline, and reset it to N_TTY. | |
2515 | * N.B. why reset ldisc when we're releasing the memory?? | |
2516 | * | |
2517 | * FIXME: this MUST get fixed for the new reflocking | |
2518 | */ | |
2519 | if (tty->ldisc.close) | |
2520 | (tty->ldisc.close)(tty); | |
2521 | tty_ldisc_put(tty->ldisc.num); | |
2522 | ||
2523 | /* | |
2524 | * Switch the line discipline back | |
2525 | */ | |
2526 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
2527 | tty_set_termios_ldisc(tty,N_TTY); | |
2528 | if (o_tty) { | |
2529 | /* FIXME: could o_tty be in setldisc here ? */ | |
2530 | clear_bit(TTY_LDISC, &o_tty->flags); | |
2531 | if (o_tty->ldisc.close) | |
2532 | (o_tty->ldisc.close)(o_tty); | |
2533 | tty_ldisc_put(o_tty->ldisc.num); | |
2534 | tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); | |
2535 | tty_set_termios_ldisc(o_tty,N_TTY); | |
2536 | } | |
2537 | /* | |
d5698c28 | 2538 | * The release_tty function takes care of the details of clearing |
1da177e4 LT |
2539 | * the slots and preserving the termios structure. |
2540 | */ | |
d5698c28 | 2541 | release_tty(tty, idx); |
1da177e4 LT |
2542 | |
2543 | #ifdef CONFIG_UNIX98_PTYS | |
2544 | /* Make this pty number available for reallocation */ | |
2545 | if (devpts) { | |
2546 | down(&allocated_ptys_lock); | |
2547 | idr_remove(&allocated_ptys, idx); | |
2548 | up(&allocated_ptys_lock); | |
2549 | } | |
2550 | #endif | |
2551 | ||
2552 | } | |
2553 | ||
af9b897e AC |
2554 | /** |
2555 | * tty_open - open a tty device | |
2556 | * @inode: inode of device file | |
2557 | * @filp: file pointer to tty | |
1da177e4 | 2558 | * |
af9b897e AC |
2559 | * tty_open and tty_release keep up the tty count that contains the |
2560 | * number of opens done on a tty. We cannot use the inode-count, as | |
2561 | * different inodes might point to the same tty. | |
1da177e4 | 2562 | * |
af9b897e AC |
2563 | * Open-counting is needed for pty masters, as well as for keeping |
2564 | * track of serial lines: DTR is dropped when the last close happens. | |
2565 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
2566 | * | |
2567 | * The termios state of a pty is reset on first open so that | |
2568 | * settings don't persist across reuse. | |
2569 | * | |
24ec839c PZ |
2570 | * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. |
2571 | * tty->count should protect the rest. | |
2572 | * ->siglock protects ->signal/->sighand | |
1da177e4 | 2573 | */ |
af9b897e | 2574 | |
1da177e4 LT |
2575 | static int tty_open(struct inode * inode, struct file * filp) |
2576 | { | |
2577 | struct tty_struct *tty; | |
2578 | int noctty, retval; | |
2579 | struct tty_driver *driver; | |
2580 | int index; | |
2581 | dev_t device = inode->i_rdev; | |
2582 | unsigned short saved_flags = filp->f_flags; | |
2583 | ||
2584 | nonseekable_open(inode, filp); | |
2585 | ||
2586 | retry_open: | |
2587 | noctty = filp->f_flags & O_NOCTTY; | |
2588 | index = -1; | |
2589 | retval = 0; | |
2590 | ||
70522e12 | 2591 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2592 | |
2593 | if (device == MKDEV(TTYAUX_MAJOR,0)) { | |
24ec839c PZ |
2594 | tty = get_current_tty(); |
2595 | if (!tty) { | |
70522e12 | 2596 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2597 | return -ENXIO; |
2598 | } | |
24ec839c PZ |
2599 | driver = tty->driver; |
2600 | index = tty->index; | |
1da177e4 LT |
2601 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
2602 | /* noctty = 1; */ | |
2603 | goto got_driver; | |
2604 | } | |
2605 | #ifdef CONFIG_VT | |
2606 | if (device == MKDEV(TTY_MAJOR,0)) { | |
2607 | extern struct tty_driver *console_driver; | |
2608 | driver = console_driver; | |
2609 | index = fg_console; | |
2610 | noctty = 1; | |
2611 | goto got_driver; | |
2612 | } | |
2613 | #endif | |
2614 | if (device == MKDEV(TTYAUX_MAJOR,1)) { | |
2615 | driver = console_device(&index); | |
2616 | if (driver) { | |
2617 | /* Don't let /dev/console block */ | |
2618 | filp->f_flags |= O_NONBLOCK; | |
2619 | noctty = 1; | |
2620 | goto got_driver; | |
2621 | } | |
70522e12 | 2622 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2623 | return -ENODEV; |
2624 | } | |
2625 | ||
2626 | driver = get_tty_driver(device, &index); | |
2627 | if (!driver) { | |
70522e12 | 2628 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2629 | return -ENODEV; |
2630 | } | |
2631 | got_driver: | |
2632 | retval = init_dev(driver, index, &tty); | |
70522e12 | 2633 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2634 | if (retval) |
2635 | return retval; | |
2636 | ||
2637 | filp->private_data = tty; | |
2638 | file_move(filp, &tty->tty_files); | |
2639 | check_tty_count(tty, "tty_open"); | |
2640 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2641 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2642 | noctty = 1; | |
2643 | #ifdef TTY_DEBUG_HANGUP | |
2644 | printk(KERN_DEBUG "opening %s...", tty->name); | |
2645 | #endif | |
2646 | if (!retval) { | |
2647 | if (tty->driver->open) | |
2648 | retval = tty->driver->open(tty, filp); | |
2649 | else | |
2650 | retval = -ENODEV; | |
2651 | } | |
2652 | filp->f_flags = saved_flags; | |
2653 | ||
2654 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) | |
2655 | retval = -EBUSY; | |
2656 | ||
2657 | if (retval) { | |
2658 | #ifdef TTY_DEBUG_HANGUP | |
2659 | printk(KERN_DEBUG "error %d in opening %s...", retval, | |
2660 | tty->name); | |
2661 | #endif | |
2662 | release_dev(filp); | |
2663 | if (retval != -ERESTARTSYS) | |
2664 | return retval; | |
2665 | if (signal_pending(current)) | |
2666 | return retval; | |
2667 | schedule(); | |
2668 | /* | |
2669 | * Need to reset f_op in case a hangup happened. | |
2670 | */ | |
2671 | if (filp->f_op == &hung_up_tty_fops) | |
2672 | filp->f_op = &tty_fops; | |
2673 | goto retry_open; | |
2674 | } | |
24ec839c PZ |
2675 | |
2676 | mutex_lock(&tty_mutex); | |
2677 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2678 | if (!noctty && |
2679 | current->signal->leader && | |
2680 | !current->signal->tty && | |
ab521dc0 | 2681 | tty->session == NULL) |
2a65f1d9 | 2682 | __proc_set_tty(current, tty); |
24ec839c PZ |
2683 | spin_unlock_irq(¤t->sighand->siglock); |
2684 | mutex_unlock(&tty_mutex); | |
522ed776 | 2685 | tty_audit_opening(); |
1da177e4 LT |
2686 | return 0; |
2687 | } | |
2688 | ||
2689 | #ifdef CONFIG_UNIX98_PTYS | |
af9b897e AC |
2690 | /** |
2691 | * ptmx_open - open a unix 98 pty master | |
2692 | * @inode: inode of device file | |
2693 | * @filp: file pointer to tty | |
2694 | * | |
2695 | * Allocate a unix98 pty master device from the ptmx driver. | |
2696 | * | |
2697 | * Locking: tty_mutex protects theinit_dev work. tty->count should | |
2698 | protect the rest. | |
2699 | * allocated_ptys_lock handles the list of free pty numbers | |
2700 | */ | |
2701 | ||
1da177e4 LT |
2702 | static int ptmx_open(struct inode * inode, struct file * filp) |
2703 | { | |
2704 | struct tty_struct *tty; | |
2705 | int retval; | |
2706 | int index; | |
2707 | int idr_ret; | |
2708 | ||
2709 | nonseekable_open(inode, filp); | |
2710 | ||
2711 | /* find a device that is not in use. */ | |
2712 | down(&allocated_ptys_lock); | |
2713 | if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { | |
2714 | up(&allocated_ptys_lock); | |
2715 | return -ENOMEM; | |
2716 | } | |
2717 | idr_ret = idr_get_new(&allocated_ptys, NULL, &index); | |
2718 | if (idr_ret < 0) { | |
2719 | up(&allocated_ptys_lock); | |
2720 | if (idr_ret == -EAGAIN) | |
2721 | return -ENOMEM; | |
2722 | return -EIO; | |
2723 | } | |
2724 | if (index >= pty_limit) { | |
2725 | idr_remove(&allocated_ptys, index); | |
2726 | up(&allocated_ptys_lock); | |
2727 | return -EIO; | |
2728 | } | |
2729 | up(&allocated_ptys_lock); | |
2730 | ||
70522e12 | 2731 | mutex_lock(&tty_mutex); |
1da177e4 | 2732 | retval = init_dev(ptm_driver, index, &tty); |
70522e12 | 2733 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2734 | |
2735 | if (retval) | |
2736 | goto out; | |
2737 | ||
2738 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
2739 | filp->private_data = tty; | |
2740 | file_move(filp, &tty->tty_files); | |
2741 | ||
2742 | retval = -ENOMEM; | |
2743 | if (devpts_pty_new(tty->link)) | |
2744 | goto out1; | |
2745 | ||
2746 | check_tty_count(tty, "tty_open"); | |
2747 | retval = ptm_driver->open(tty, filp); | |
522ed776 MT |
2748 | if (!retval) { |
2749 | tty_audit_opening(); | |
1da177e4 | 2750 | return 0; |
522ed776 | 2751 | } |
1da177e4 LT |
2752 | out1: |
2753 | release_dev(filp); | |
9453a5ad | 2754 | return retval; |
1da177e4 LT |
2755 | out: |
2756 | down(&allocated_ptys_lock); | |
2757 | idr_remove(&allocated_ptys, index); | |
2758 | up(&allocated_ptys_lock); | |
2759 | return retval; | |
2760 | } | |
2761 | #endif | |
2762 | ||
af9b897e AC |
2763 | /** |
2764 | * tty_release - vfs callback for close | |
2765 | * @inode: inode of tty | |
2766 | * @filp: file pointer for handle to tty | |
2767 | * | |
2768 | * Called the last time each file handle is closed that references | |
2769 | * this tty. There may however be several such references. | |
2770 | * | |
2771 | * Locking: | |
2772 | * Takes bkl. See release_dev | |
2773 | */ | |
2774 | ||
1da177e4 LT |
2775 | static int tty_release(struct inode * inode, struct file * filp) |
2776 | { | |
2777 | lock_kernel(); | |
2778 | release_dev(filp); | |
2779 | unlock_kernel(); | |
2780 | return 0; | |
2781 | } | |
2782 | ||
af9b897e AC |
2783 | /** |
2784 | * tty_poll - check tty status | |
2785 | * @filp: file being polled | |
2786 | * @wait: poll wait structures to update | |
2787 | * | |
2788 | * Call the line discipline polling method to obtain the poll | |
2789 | * status of the device. | |
2790 | * | |
2791 | * Locking: locks called line discipline but ldisc poll method | |
2792 | * may be re-entered freely by other callers. | |
2793 | */ | |
2794 | ||
1da177e4 LT |
2795 | static unsigned int tty_poll(struct file * filp, poll_table * wait) |
2796 | { | |
2797 | struct tty_struct * tty; | |
2798 | struct tty_ldisc *ld; | |
2799 | int ret = 0; | |
2800 | ||
2801 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2802 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) |
1da177e4 LT |
2803 | return 0; |
2804 | ||
2805 | ld = tty_ldisc_ref_wait(tty); | |
2806 | if (ld->poll) | |
2807 | ret = (ld->poll)(tty, filp, wait); | |
2808 | tty_ldisc_deref(ld); | |
2809 | return ret; | |
2810 | } | |
2811 | ||
2812 | static int tty_fasync(int fd, struct file * filp, int on) | |
2813 | { | |
2814 | struct tty_struct * tty; | |
2815 | int retval; | |
2816 | ||
2817 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2818 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) |
1da177e4 LT |
2819 | return 0; |
2820 | ||
2821 | retval = fasync_helper(fd, filp, on, &tty->fasync); | |
2822 | if (retval <= 0) | |
2823 | return retval; | |
2824 | ||
2825 | if (on) { | |
ab521dc0 EB |
2826 | enum pid_type type; |
2827 | struct pid *pid; | |
1da177e4 LT |
2828 | if (!waitqueue_active(&tty->read_wait)) |
2829 | tty->minimum_to_wake = 1; | |
ab521dc0 EB |
2830 | if (tty->pgrp) { |
2831 | pid = tty->pgrp; | |
2832 | type = PIDTYPE_PGID; | |
2833 | } else { | |
2834 | pid = task_pid(current); | |
2835 | type = PIDTYPE_PID; | |
2836 | } | |
2837 | retval = __f_setown(filp, pid, type, 0); | |
1da177e4 LT |
2838 | if (retval) |
2839 | return retval; | |
2840 | } else { | |
2841 | if (!tty->fasync && !waitqueue_active(&tty->read_wait)) | |
2842 | tty->minimum_to_wake = N_TTY_BUF_SIZE; | |
2843 | } | |
2844 | return 0; | |
2845 | } | |
2846 | ||
af9b897e AC |
2847 | /** |
2848 | * tiocsti - fake input character | |
2849 | * @tty: tty to fake input into | |
2850 | * @p: pointer to character | |
2851 | * | |
2852 | * Fake input to a tty device. Does the neccessary locking and | |
2853 | * input management. | |
2854 | * | |
2855 | * FIXME: does not honour flow control ?? | |
2856 | * | |
2857 | * Locking: | |
2858 | * Called functions take tty_ldisc_lock | |
2859 | * current->signal->tty check is safe without locks | |
28298232 AC |
2860 | * |
2861 | * FIXME: may race normal receive processing | |
af9b897e AC |
2862 | */ |
2863 | ||
1da177e4 LT |
2864 | static int tiocsti(struct tty_struct *tty, char __user *p) |
2865 | { | |
2866 | char ch, mbz = 0; | |
2867 | struct tty_ldisc *ld; | |
2868 | ||
2869 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) | |
2870 | return -EPERM; | |
2871 | if (get_user(ch, p)) | |
2872 | return -EFAULT; | |
2873 | ld = tty_ldisc_ref_wait(tty); | |
2874 | ld->receive_buf(tty, &ch, &mbz, 1); | |
2875 | tty_ldisc_deref(ld); | |
2876 | return 0; | |
2877 | } | |
2878 | ||
af9b897e AC |
2879 | /** |
2880 | * tiocgwinsz - implement window query ioctl | |
2881 | * @tty; tty | |
2882 | * @arg: user buffer for result | |
2883 | * | |
808a0d38 | 2884 | * Copies the kernel idea of the window size into the user buffer. |
af9b897e | 2885 | * |
24ec839c | 2886 | * Locking: tty->termios_mutex is taken to ensure the winsize data |
808a0d38 | 2887 | * is consistent. |
af9b897e AC |
2888 | */ |
2889 | ||
1da177e4 LT |
2890 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) |
2891 | { | |
808a0d38 AC |
2892 | int err; |
2893 | ||
5785c95b | 2894 | mutex_lock(&tty->termios_mutex); |
808a0d38 | 2895 | err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); |
5785c95b | 2896 | mutex_unlock(&tty->termios_mutex); |
808a0d38 AC |
2897 | |
2898 | return err ? -EFAULT: 0; | |
1da177e4 LT |
2899 | } |
2900 | ||
af9b897e AC |
2901 | /** |
2902 | * tiocswinsz - implement window size set ioctl | |
2903 | * @tty; tty | |
2904 | * @arg: user buffer for result | |
2905 | * | |
2906 | * Copies the user idea of the window size to the kernel. Traditionally | |
2907 | * this is just advisory information but for the Linux console it | |
2908 | * actually has driver level meaning and triggers a VC resize. | |
2909 | * | |
2910 | * Locking: | |
ca9bda00 AC |
2911 | * Called function use the console_sem is used to ensure we do |
2912 | * not try and resize the console twice at once. | |
24ec839c PZ |
2913 | * The tty->termios_mutex is used to ensure we don't double |
2914 | * resize and get confused. Lock order - tty->termios_mutex before | |
ca9bda00 | 2915 | * console sem |
af9b897e AC |
2916 | */ |
2917 | ||
1da177e4 LT |
2918 | static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, |
2919 | struct winsize __user * arg) | |
2920 | { | |
2921 | struct winsize tmp_ws; | |
2922 | ||
2923 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
2924 | return -EFAULT; | |
ca9bda00 | 2925 | |
5785c95b | 2926 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 2927 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
ca9bda00 AC |
2928 | goto done; |
2929 | ||
1da177e4 LT |
2930 | #ifdef CONFIG_VT |
2931 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { | |
5785c95b AV |
2932 | if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, |
2933 | tmp_ws.ws_row)) { | |
2934 | mutex_unlock(&tty->termios_mutex); | |
ca9bda00 AC |
2935 | return -ENXIO; |
2936 | } | |
1da177e4 LT |
2937 | } |
2938 | #endif | |
ab521dc0 EB |
2939 | if (tty->pgrp) |
2940 | kill_pgrp(tty->pgrp, SIGWINCH, 1); | |
2941 | if ((real_tty->pgrp != tty->pgrp) && real_tty->pgrp) | |
2942 | kill_pgrp(real_tty->pgrp, SIGWINCH, 1); | |
1da177e4 LT |
2943 | tty->winsize = tmp_ws; |
2944 | real_tty->winsize = tmp_ws; | |
ca9bda00 | 2945 | done: |
5785c95b | 2946 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
2947 | return 0; |
2948 | } | |
2949 | ||
af9b897e AC |
2950 | /** |
2951 | * tioccons - allow admin to move logical console | |
2952 | * @file: the file to become console | |
2953 | * | |
2954 | * Allow the adminstrator to move the redirected console device | |
2955 | * | |
2956 | * Locking: uses redirect_lock to guard the redirect information | |
2957 | */ | |
2958 | ||
1da177e4 LT |
2959 | static int tioccons(struct file *file) |
2960 | { | |
2961 | if (!capable(CAP_SYS_ADMIN)) | |
2962 | return -EPERM; | |
2963 | if (file->f_op->write == redirected_tty_write) { | |
2964 | struct file *f; | |
2965 | spin_lock(&redirect_lock); | |
2966 | f = redirect; | |
2967 | redirect = NULL; | |
2968 | spin_unlock(&redirect_lock); | |
2969 | if (f) | |
2970 | fput(f); | |
2971 | return 0; | |
2972 | } | |
2973 | spin_lock(&redirect_lock); | |
2974 | if (redirect) { | |
2975 | spin_unlock(&redirect_lock); | |
2976 | return -EBUSY; | |
2977 | } | |
2978 | get_file(file); | |
2979 | redirect = file; | |
2980 | spin_unlock(&redirect_lock); | |
2981 | return 0; | |
2982 | } | |
2983 | ||
af9b897e AC |
2984 | /** |
2985 | * fionbio - non blocking ioctl | |
2986 | * @file: file to set blocking value | |
2987 | * @p: user parameter | |
2988 | * | |
2989 | * Historical tty interfaces had a blocking control ioctl before | |
2990 | * the generic functionality existed. This piece of history is preserved | |
2991 | * in the expected tty API of posix OS's. | |
2992 | * | |
2993 | * Locking: none, the open fle handle ensures it won't go away. | |
2994 | */ | |
1da177e4 LT |
2995 | |
2996 | static int fionbio(struct file *file, int __user *p) | |
2997 | { | |
2998 | int nonblock; | |
2999 | ||
3000 | if (get_user(nonblock, p)) | |
3001 | return -EFAULT; | |
3002 | ||
3003 | if (nonblock) | |
3004 | file->f_flags |= O_NONBLOCK; | |
3005 | else | |
3006 | file->f_flags &= ~O_NONBLOCK; | |
3007 | return 0; | |
3008 | } | |
3009 | ||
af9b897e AC |
3010 | /** |
3011 | * tiocsctty - set controlling tty | |
3012 | * @tty: tty structure | |
3013 | * @arg: user argument | |
3014 | * | |
3015 | * This ioctl is used to manage job control. It permits a session | |
3016 | * leader to set this tty as the controlling tty for the session. | |
3017 | * | |
3018 | * Locking: | |
28298232 | 3019 | * Takes tty_mutex() to protect tty instance |
24ec839c PZ |
3020 | * Takes tasklist_lock internally to walk sessions |
3021 | * Takes ->siglock() when updating signal->tty | |
af9b897e AC |
3022 | */ |
3023 | ||
1da177e4 LT |
3024 | static int tiocsctty(struct tty_struct *tty, int arg) |
3025 | { | |
24ec839c | 3026 | int ret = 0; |
ab521dc0 | 3027 | if (current->signal->leader && (task_session(current) == tty->session)) |
24ec839c PZ |
3028 | return ret; |
3029 | ||
3030 | mutex_lock(&tty_mutex); | |
1da177e4 LT |
3031 | /* |
3032 | * The process must be a session leader and | |
3033 | * not have a controlling tty already. | |
3034 | */ | |
24ec839c PZ |
3035 | if (!current->signal->leader || current->signal->tty) { |
3036 | ret = -EPERM; | |
3037 | goto unlock; | |
3038 | } | |
3039 | ||
ab521dc0 | 3040 | if (tty->session) { |
1da177e4 LT |
3041 | /* |
3042 | * This tty is already the controlling | |
3043 | * tty for another session group! | |
3044 | */ | |
3045 | if ((arg == 1) && capable(CAP_SYS_ADMIN)) { | |
3046 | /* | |
3047 | * Steal it away | |
3048 | */ | |
1da177e4 | 3049 | read_lock(&tasklist_lock); |
24ec839c | 3050 | session_clear_tty(tty->session); |
1da177e4 | 3051 | read_unlock(&tasklist_lock); |
24ec839c PZ |
3052 | } else { |
3053 | ret = -EPERM; | |
3054 | goto unlock; | |
3055 | } | |
1da177e4 | 3056 | } |
24ec839c PZ |
3057 | proc_set_tty(current, tty); |
3058 | unlock: | |
28298232 | 3059 | mutex_unlock(&tty_mutex); |
24ec839c | 3060 | return ret; |
1da177e4 LT |
3061 | } |
3062 | ||
af9b897e AC |
3063 | /** |
3064 | * tiocgpgrp - get process group | |
3065 | * @tty: tty passed by user | |
3066 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3067 | * @p: returned pid | |
3068 | * | |
3069 | * Obtain the process group of the tty. If there is no process group | |
3070 | * return an error. | |
3071 | * | |
24ec839c | 3072 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3073 | */ |
3074 | ||
1da177e4 LT |
3075 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3076 | { | |
3077 | /* | |
3078 | * (tty == real_tty) is a cheap way of | |
3079 | * testing if the tty is NOT a master pty. | |
3080 | */ | |
3081 | if (tty == real_tty && current->signal->tty != real_tty) | |
3082 | return -ENOTTY; | |
ab521dc0 | 3083 | return put_user(pid_nr(real_tty->pgrp), p); |
1da177e4 LT |
3084 | } |
3085 | ||
af9b897e AC |
3086 | /** |
3087 | * tiocspgrp - attempt to set process group | |
3088 | * @tty: tty passed by user | |
3089 | * @real_tty: tty side device matching tty passed by user | |
3090 | * @p: pid pointer | |
3091 | * | |
3092 | * Set the process group of the tty to the session passed. Only | |
3093 | * permitted where the tty session is our session. | |
3094 | * | |
3095 | * Locking: None | |
af9b897e AC |
3096 | */ |
3097 | ||
1da177e4 LT |
3098 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3099 | { | |
04a2e6a5 EB |
3100 | struct pid *pgrp; |
3101 | pid_t pgrp_nr; | |
1da177e4 LT |
3102 | int retval = tty_check_change(real_tty); |
3103 | ||
3104 | if (retval == -EIO) | |
3105 | return -ENOTTY; | |
3106 | if (retval) | |
3107 | return retval; | |
3108 | if (!current->signal->tty || | |
3109 | (current->signal->tty != real_tty) || | |
ab521dc0 | 3110 | (real_tty->session != task_session(current))) |
1da177e4 | 3111 | return -ENOTTY; |
04a2e6a5 | 3112 | if (get_user(pgrp_nr, p)) |
1da177e4 | 3113 | return -EFAULT; |
04a2e6a5 | 3114 | if (pgrp_nr < 0) |
1da177e4 | 3115 | return -EINVAL; |
04a2e6a5 EB |
3116 | rcu_read_lock(); |
3117 | pgrp = find_pid(pgrp_nr); | |
3118 | retval = -ESRCH; | |
3119 | if (!pgrp) | |
3120 | goto out_unlock; | |
3121 | retval = -EPERM; | |
3122 | if (session_of_pgrp(pgrp) != task_session(current)) | |
3123 | goto out_unlock; | |
3124 | retval = 0; | |
ab521dc0 EB |
3125 | put_pid(real_tty->pgrp); |
3126 | real_tty->pgrp = get_pid(pgrp); | |
04a2e6a5 EB |
3127 | out_unlock: |
3128 | rcu_read_unlock(); | |
3129 | return retval; | |
1da177e4 LT |
3130 | } |
3131 | ||
af9b897e AC |
3132 | /** |
3133 | * tiocgsid - get session id | |
3134 | * @tty: tty passed by user | |
3135 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3136 | * @p: pointer to returned session id | |
3137 | * | |
3138 | * Obtain the session id of the tty. If there is no session | |
3139 | * return an error. | |
3140 | * | |
24ec839c | 3141 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3142 | */ |
3143 | ||
1da177e4 LT |
3144 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3145 | { | |
3146 | /* | |
3147 | * (tty == real_tty) is a cheap way of | |
3148 | * testing if the tty is NOT a master pty. | |
3149 | */ | |
3150 | if (tty == real_tty && current->signal->tty != real_tty) | |
3151 | return -ENOTTY; | |
ab521dc0 | 3152 | if (!real_tty->session) |
1da177e4 | 3153 | return -ENOTTY; |
ab521dc0 | 3154 | return put_user(pid_nr(real_tty->session), p); |
1da177e4 LT |
3155 | } |
3156 | ||
af9b897e AC |
3157 | /** |
3158 | * tiocsetd - set line discipline | |
3159 | * @tty: tty device | |
3160 | * @p: pointer to user data | |
3161 | * | |
3162 | * Set the line discipline according to user request. | |
3163 | * | |
3164 | * Locking: see tty_set_ldisc, this function is just a helper | |
3165 | */ | |
3166 | ||
1da177e4 LT |
3167 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
3168 | { | |
3169 | int ldisc; | |
3170 | ||
3171 | if (get_user(ldisc, p)) | |
3172 | return -EFAULT; | |
3173 | return tty_set_ldisc(tty, ldisc); | |
3174 | } | |
3175 | ||
af9b897e AC |
3176 | /** |
3177 | * send_break - performed time break | |
3178 | * @tty: device to break on | |
3179 | * @duration: timeout in mS | |
3180 | * | |
3181 | * Perform a timed break on hardware that lacks its own driver level | |
3182 | * timed break functionality. | |
3183 | * | |
3184 | * Locking: | |
28298232 | 3185 | * atomic_write_lock serializes |
af9b897e | 3186 | * |
af9b897e AC |
3187 | */ |
3188 | ||
b20f3ae5 | 3189 | static int send_break(struct tty_struct *tty, unsigned int duration) |
1da177e4 | 3190 | { |
9c1729db | 3191 | if (tty_write_lock(tty, 0) < 0) |
28298232 | 3192 | return -EINTR; |
1da177e4 | 3193 | tty->driver->break_ctl(tty, -1); |
9c1729db | 3194 | if (!signal_pending(current)) |
b20f3ae5 | 3195 | msleep_interruptible(duration); |
1da177e4 | 3196 | tty->driver->break_ctl(tty, 0); |
9c1729db | 3197 | tty_write_unlock(tty); |
1da177e4 LT |
3198 | if (signal_pending(current)) |
3199 | return -EINTR; | |
3200 | return 0; | |
3201 | } | |
3202 | ||
af9b897e AC |
3203 | /** |
3204 | * tiocmget - get modem status | |
3205 | * @tty: tty device | |
3206 | * @file: user file pointer | |
3207 | * @p: pointer to result | |
3208 | * | |
3209 | * Obtain the modem status bits from the tty driver if the feature | |
3210 | * is supported. Return -EINVAL if it is not available. | |
3211 | * | |
3212 | * Locking: none (up to the driver) | |
3213 | */ | |
3214 | ||
3215 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) | |
1da177e4 LT |
3216 | { |
3217 | int retval = -EINVAL; | |
3218 | ||
3219 | if (tty->driver->tiocmget) { | |
3220 | retval = tty->driver->tiocmget(tty, file); | |
3221 | ||
3222 | if (retval >= 0) | |
3223 | retval = put_user(retval, p); | |
3224 | } | |
3225 | return retval; | |
3226 | } | |
3227 | ||
af9b897e AC |
3228 | /** |
3229 | * tiocmset - set modem status | |
3230 | * @tty: tty device | |
3231 | * @file: user file pointer | |
3232 | * @cmd: command - clear bits, set bits or set all | |
3233 | * @p: pointer to desired bits | |
3234 | * | |
3235 | * Set the modem status bits from the tty driver if the feature | |
3236 | * is supported. Return -EINVAL if it is not available. | |
3237 | * | |
3238 | * Locking: none (up to the driver) | |
3239 | */ | |
3240 | ||
3241 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, | |
1da177e4 LT |
3242 | unsigned __user *p) |
3243 | { | |
3244 | int retval = -EINVAL; | |
3245 | ||
3246 | if (tty->driver->tiocmset) { | |
3247 | unsigned int set, clear, val; | |
3248 | ||
3249 | retval = get_user(val, p); | |
3250 | if (retval) | |
3251 | return retval; | |
3252 | ||
3253 | set = clear = 0; | |
3254 | switch (cmd) { | |
3255 | case TIOCMBIS: | |
3256 | set = val; | |
3257 | break; | |
3258 | case TIOCMBIC: | |
3259 | clear = val; | |
3260 | break; | |
3261 | case TIOCMSET: | |
3262 | set = val; | |
3263 | clear = ~val; | |
3264 | break; | |
3265 | } | |
3266 | ||
3267 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3268 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3269 | ||
3270 | retval = tty->driver->tiocmset(tty, file, set, clear); | |
3271 | } | |
3272 | return retval; | |
3273 | } | |
3274 | ||
3275 | /* | |
3276 | * Split this up, as gcc can choke on it otherwise.. | |
3277 | */ | |
3278 | int tty_ioctl(struct inode * inode, struct file * file, | |
3279 | unsigned int cmd, unsigned long arg) | |
3280 | { | |
3281 | struct tty_struct *tty, *real_tty; | |
3282 | void __user *p = (void __user *)arg; | |
3283 | int retval; | |
3284 | struct tty_ldisc *ld; | |
3285 | ||
3286 | tty = (struct tty_struct *)file->private_data; | |
3287 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3288 | return -EINVAL; | |
3289 | ||
28298232 AC |
3290 | /* CHECKME: is this safe as one end closes ? */ |
3291 | ||
1da177e4 LT |
3292 | real_tty = tty; |
3293 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
3294 | tty->driver->subtype == PTY_TYPE_MASTER) | |
3295 | real_tty = tty->link; | |
3296 | ||
3297 | /* | |
3298 | * Break handling by driver | |
3299 | */ | |
3300 | if (!tty->driver->break_ctl) { | |
3301 | switch(cmd) { | |
3302 | case TIOCSBRK: | |
3303 | case TIOCCBRK: | |
3304 | if (tty->driver->ioctl) | |
3305 | return tty->driver->ioctl(tty, file, cmd, arg); | |
3306 | return -EINVAL; | |
3307 | ||
3308 | /* These two ioctl's always return success; even if */ | |
3309 | /* the driver doesn't support them. */ | |
3310 | case TCSBRK: | |
3311 | case TCSBRKP: | |
3312 | if (!tty->driver->ioctl) | |
3313 | return 0; | |
3314 | retval = tty->driver->ioctl(tty, file, cmd, arg); | |
3315 | if (retval == -ENOIOCTLCMD) | |
3316 | retval = 0; | |
3317 | return retval; | |
3318 | } | |
3319 | } | |
3320 | ||
3321 | /* | |
3322 | * Factor out some common prep work | |
3323 | */ | |
3324 | switch (cmd) { | |
3325 | case TIOCSETD: | |
3326 | case TIOCSBRK: | |
3327 | case TIOCCBRK: | |
3328 | case TCSBRK: | |
3329 | case TCSBRKP: | |
3330 | retval = tty_check_change(tty); | |
3331 | if (retval) | |
3332 | return retval; | |
3333 | if (cmd != TIOCCBRK) { | |
3334 | tty_wait_until_sent(tty, 0); | |
3335 | if (signal_pending(current)) | |
3336 | return -EINTR; | |
3337 | } | |
3338 | break; | |
3339 | } | |
3340 | ||
3341 | switch (cmd) { | |
3342 | case TIOCSTI: | |
3343 | return tiocsti(tty, p); | |
3344 | case TIOCGWINSZ: | |
3345 | return tiocgwinsz(tty, p); | |
3346 | case TIOCSWINSZ: | |
3347 | return tiocswinsz(tty, real_tty, p); | |
3348 | case TIOCCONS: | |
3349 | return real_tty!=tty ? -EINVAL : tioccons(file); | |
3350 | case FIONBIO: | |
3351 | return fionbio(file, p); | |
3352 | case TIOCEXCL: | |
3353 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
3354 | return 0; | |
3355 | case TIOCNXCL: | |
3356 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
3357 | return 0; | |
3358 | case TIOCNOTTY: | |
3359 | if (current->signal->tty != tty) | |
3360 | return -ENOTTY; | |
98a27ba4 | 3361 | no_tty(); |
1da177e4 LT |
3362 | return 0; |
3363 | case TIOCSCTTY: | |
3364 | return tiocsctty(tty, arg); | |
3365 | case TIOCGPGRP: | |
3366 | return tiocgpgrp(tty, real_tty, p); | |
3367 | case TIOCSPGRP: | |
3368 | return tiocspgrp(tty, real_tty, p); | |
3369 | case TIOCGSID: | |
3370 | return tiocgsid(tty, real_tty, p); | |
3371 | case TIOCGETD: | |
3372 | /* FIXME: check this is ok */ | |
3373 | return put_user(tty->ldisc.num, (int __user *)p); | |
3374 | case TIOCSETD: | |
3375 | return tiocsetd(tty, p); | |
3376 | #ifdef CONFIG_VT | |
3377 | case TIOCLINUX: | |
3378 | return tioclinux(tty, arg); | |
3379 | #endif | |
3380 | /* | |
3381 | * Break handling | |
3382 | */ | |
3383 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
3384 | tty->driver->break_ctl(tty, -1); | |
3385 | return 0; | |
3386 | ||
3387 | case TIOCCBRK: /* Turn break off, unconditionally */ | |
3388 | tty->driver->break_ctl(tty, 0); | |
3389 | return 0; | |
3390 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
283fef59 PF |
3391 | /* non-zero arg means wait for all output data |
3392 | * to be sent (performed above) but don't send break. | |
3393 | * This is used by the tcdrain() termios function. | |
1da177e4 LT |
3394 | */ |
3395 | if (!arg) | |
b20f3ae5 | 3396 | return send_break(tty, 250); |
1da177e4 LT |
3397 | return 0; |
3398 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
b20f3ae5 | 3399 | return send_break(tty, arg ? arg*100 : 250); |
1da177e4 LT |
3400 | |
3401 | case TIOCMGET: | |
3402 | return tty_tiocmget(tty, file, p); | |
3403 | ||
3404 | case TIOCMSET: | |
3405 | case TIOCMBIC: | |
3406 | case TIOCMBIS: | |
3407 | return tty_tiocmset(tty, file, cmd, p); | |
c5c34d48 PF |
3408 | case TCFLSH: |
3409 | switch (arg) { | |
3410 | case TCIFLUSH: | |
3411 | case TCIOFLUSH: | |
3412 | /* flush tty buffer and allow ldisc to process ioctl */ | |
3413 | tty_buffer_flush(tty); | |
3414 | break; | |
3415 | } | |
3416 | break; | |
1da177e4 LT |
3417 | } |
3418 | if (tty->driver->ioctl) { | |
3419 | retval = (tty->driver->ioctl)(tty, file, cmd, arg); | |
3420 | if (retval != -ENOIOCTLCMD) | |
3421 | return retval; | |
3422 | } | |
3423 | ld = tty_ldisc_ref_wait(tty); | |
3424 | retval = -EINVAL; | |
3425 | if (ld->ioctl) { | |
3426 | retval = ld->ioctl(tty, file, cmd, arg); | |
3427 | if (retval == -ENOIOCTLCMD) | |
3428 | retval = -EINVAL; | |
3429 | } | |
3430 | tty_ldisc_deref(ld); | |
3431 | return retval; | |
3432 | } | |
3433 | ||
e10cc1df PF |
3434 | #ifdef CONFIG_COMPAT |
3435 | static long tty_compat_ioctl(struct file * file, unsigned int cmd, | |
3436 | unsigned long arg) | |
3437 | { | |
3438 | struct inode *inode = file->f_dentry->d_inode; | |
3439 | struct tty_struct *tty = file->private_data; | |
3440 | struct tty_ldisc *ld; | |
3441 | int retval = -ENOIOCTLCMD; | |
3442 | ||
3443 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3444 | return -EINVAL; | |
3445 | ||
3446 | if (tty->driver->compat_ioctl) { | |
3447 | retval = (tty->driver->compat_ioctl)(tty, file, cmd, arg); | |
3448 | if (retval != -ENOIOCTLCMD) | |
3449 | return retval; | |
3450 | } | |
3451 | ||
3452 | ld = tty_ldisc_ref_wait(tty); | |
3453 | if (ld->compat_ioctl) | |
3454 | retval = ld->compat_ioctl(tty, file, cmd, arg); | |
3455 | tty_ldisc_deref(ld); | |
3456 | ||
3457 | return retval; | |
3458 | } | |
3459 | #endif | |
1da177e4 LT |
3460 | |
3461 | /* | |
3462 | * This implements the "Secure Attention Key" --- the idea is to | |
3463 | * prevent trojan horses by killing all processes associated with this | |
3464 | * tty when the user hits the "Secure Attention Key". Required for | |
3465 | * super-paranoid applications --- see the Orange Book for more details. | |
3466 | * | |
3467 | * This code could be nicer; ideally it should send a HUP, wait a few | |
3468 | * seconds, then send a INT, and then a KILL signal. But you then | |
3469 | * have to coordinate with the init process, since all processes associated | |
3470 | * with the current tty must be dead before the new getty is allowed | |
3471 | * to spawn. | |
3472 | * | |
3473 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
3474 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
3475 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
3476 | * | |
3477 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
3478 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
3479 | */ | |
8b6312f4 | 3480 | void __do_SAK(struct tty_struct *tty) |
1da177e4 LT |
3481 | { |
3482 | #ifdef TTY_SOFT_SAK | |
3483 | tty_hangup(tty); | |
3484 | #else | |
652486fb | 3485 | struct task_struct *g, *p; |
ab521dc0 | 3486 | struct pid *session; |
1da177e4 LT |
3487 | int i; |
3488 | struct file *filp; | |
badf1662 | 3489 | struct fdtable *fdt; |
1da177e4 LT |
3490 | |
3491 | if (!tty) | |
3492 | return; | |
24ec839c | 3493 | session = tty->session; |
1da177e4 | 3494 | |
b3f13deb | 3495 | tty_ldisc_flush(tty); |
1da177e4 LT |
3496 | |
3497 | if (tty->driver->flush_buffer) | |
3498 | tty->driver->flush_buffer(tty); | |
3499 | ||
3500 | read_lock(&tasklist_lock); | |
652486fb | 3501 | /* Kill the entire session */ |
ab521dc0 | 3502 | do_each_pid_task(session, PIDTYPE_SID, p) { |
652486fb | 3503 | printk(KERN_NOTICE "SAK: killed process %d" |
937949d9 | 3504 | " (%s): process_session(p)==tty->session\n", |
652486fb EB |
3505 | p->pid, p->comm); |
3506 | send_sig(SIGKILL, p, 1); | |
ab521dc0 | 3507 | } while_each_pid_task(session, PIDTYPE_SID, p); |
652486fb EB |
3508 | /* Now kill any processes that happen to have the |
3509 | * tty open. | |
3510 | */ | |
3511 | do_each_thread(g, p) { | |
3512 | if (p->signal->tty == tty) { | |
1da177e4 | 3513 | printk(KERN_NOTICE "SAK: killed process %d" |
937949d9 | 3514 | " (%s): process_session(p)==tty->session\n", |
1da177e4 LT |
3515 | p->pid, p->comm); |
3516 | send_sig(SIGKILL, p, 1); | |
3517 | continue; | |
3518 | } | |
3519 | task_lock(p); | |
3520 | if (p->files) { | |
ca99c1da DS |
3521 | /* |
3522 | * We don't take a ref to the file, so we must | |
3523 | * hold ->file_lock instead. | |
3524 | */ | |
3525 | spin_lock(&p->files->file_lock); | |
badf1662 DS |
3526 | fdt = files_fdtable(p->files); |
3527 | for (i=0; i < fdt->max_fds; i++) { | |
1da177e4 LT |
3528 | filp = fcheck_files(p->files, i); |
3529 | if (!filp) | |
3530 | continue; | |
3531 | if (filp->f_op->read == tty_read && | |
3532 | filp->private_data == tty) { | |
3533 | printk(KERN_NOTICE "SAK: killed process %d" | |
3534 | " (%s): fd#%d opened to the tty\n", | |
3535 | p->pid, p->comm, i); | |
20ac9437 | 3536 | force_sig(SIGKILL, p); |
1da177e4 LT |
3537 | break; |
3538 | } | |
3539 | } | |
ca99c1da | 3540 | spin_unlock(&p->files->file_lock); |
1da177e4 LT |
3541 | } |
3542 | task_unlock(p); | |
652486fb | 3543 | } while_each_thread(g, p); |
1da177e4 LT |
3544 | read_unlock(&tasklist_lock); |
3545 | #endif | |
3546 | } | |
3547 | ||
8b6312f4 EB |
3548 | static void do_SAK_work(struct work_struct *work) |
3549 | { | |
3550 | struct tty_struct *tty = | |
3551 | container_of(work, struct tty_struct, SAK_work); | |
3552 | __do_SAK(tty); | |
3553 | } | |
3554 | ||
1da177e4 LT |
3555 | /* |
3556 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
3557 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
3558 | * the values which we write to it will be identical to the values which it | |
3559 | * already has. --akpm | |
3560 | */ | |
3561 | void do_SAK(struct tty_struct *tty) | |
3562 | { | |
3563 | if (!tty) | |
3564 | return; | |
1da177e4 LT |
3565 | schedule_work(&tty->SAK_work); |
3566 | } | |
3567 | ||
3568 | EXPORT_SYMBOL(do_SAK); | |
3569 | ||
af9b897e AC |
3570 | /** |
3571 | * flush_to_ldisc | |
65f27f38 | 3572 | * @work: tty structure passed from work queue. |
af9b897e AC |
3573 | * |
3574 | * This routine is called out of the software interrupt to flush data | |
3575 | * from the buffer chain to the line discipline. | |
3576 | * | |
3577 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
3578 | * while invoking the line discipline receive_buf method. The | |
3579 | * receive_buf method is single threaded for each tty instance. | |
1da177e4 LT |
3580 | */ |
3581 | ||
65f27f38 | 3582 | static void flush_to_ldisc(struct work_struct *work) |
1da177e4 | 3583 | { |
65f27f38 DH |
3584 | struct tty_struct *tty = |
3585 | container_of(work, struct tty_struct, buf.work.work); | |
1da177e4 LT |
3586 | unsigned long flags; |
3587 | struct tty_ldisc *disc; | |
2c3bb20f | 3588 | struct tty_buffer *tbuf, *head; |
8977d929 PF |
3589 | char *char_buf; |
3590 | unsigned char *flag_buf; | |
1da177e4 LT |
3591 | |
3592 | disc = tty_ldisc_ref(tty); | |
3593 | if (disc == NULL) /* !TTY_LDISC */ | |
3594 | return; | |
3595 | ||
808249ce | 3596 | spin_lock_irqsave(&tty->buf.lock, flags); |
2c3bb20f PF |
3597 | head = tty->buf.head; |
3598 | if (head != NULL) { | |
3599 | tty->buf.head = NULL; | |
3600 | for (;;) { | |
3601 | int count = head->commit - head->read; | |
3602 | if (!count) { | |
3603 | if (head->next == NULL) | |
3604 | break; | |
3605 | tbuf = head; | |
3606 | head = head->next; | |
3607 | tty_buffer_free(tty, tbuf); | |
3608 | continue; | |
3609 | } | |
3610 | if (!tty->receive_room) { | |
3611 | schedule_delayed_work(&tty->buf.work, 1); | |
3612 | break; | |
3613 | } | |
3614 | if (count > tty->receive_room) | |
3615 | count = tty->receive_room; | |
3616 | char_buf = head->char_buf_ptr + head->read; | |
3617 | flag_buf = head->flag_buf_ptr + head->read; | |
3618 | head->read += count; | |
8977d929 PF |
3619 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3620 | disc->receive_buf(tty, char_buf, flag_buf, count); | |
3621 | spin_lock_irqsave(&tty->buf.lock, flags); | |
3622 | } | |
2c3bb20f | 3623 | tty->buf.head = head; |
33f0f88f | 3624 | } |
808249ce | 3625 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
817d6d3b | 3626 | |
1da177e4 LT |
3627 | tty_ldisc_deref(disc); |
3628 | } | |
3629 | ||
1da177e4 LT |
3630 | /** |
3631 | * tty_flip_buffer_push - terminal | |
3632 | * @tty: tty to push | |
3633 | * | |
3634 | * Queue a push of the terminal flip buffers to the line discipline. This | |
3635 | * function must not be called from IRQ context if tty->low_latency is set. | |
3636 | * | |
3637 | * In the event of the queue being busy for flipping the work will be | |
3638 | * held off and retried later. | |
af9b897e AC |
3639 | * |
3640 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
1da177e4 LT |
3641 | */ |
3642 | ||
3643 | void tty_flip_buffer_push(struct tty_struct *tty) | |
3644 | { | |
808249ce PF |
3645 | unsigned long flags; |
3646 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 3647 | if (tty->buf.tail != NULL) |
8977d929 | 3648 | tty->buf.tail->commit = tty->buf.tail->used; |
808249ce PF |
3649 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3650 | ||
1da177e4 | 3651 | if (tty->low_latency) |
65f27f38 | 3652 | flush_to_ldisc(&tty->buf.work.work); |
1da177e4 | 3653 | else |
33f0f88f | 3654 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
3655 | } |
3656 | ||
3657 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
3658 | ||
33f0f88f | 3659 | |
af9b897e AC |
3660 | /** |
3661 | * initialize_tty_struct | |
3662 | * @tty: tty to initialize | |
3663 | * | |
3664 | * This subroutine initializes a tty structure that has been newly | |
3665 | * allocated. | |
3666 | * | |
3667 | * Locking: none - tty in question must not be exposed at this point | |
1da177e4 | 3668 | */ |
af9b897e | 3669 | |
1da177e4 LT |
3670 | static void initialize_tty_struct(struct tty_struct *tty) |
3671 | { | |
3672 | memset(tty, 0, sizeof(struct tty_struct)); | |
3673 | tty->magic = TTY_MAGIC; | |
3674 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
ab521dc0 EB |
3675 | tty->session = NULL; |
3676 | tty->pgrp = NULL; | |
1da177e4 | 3677 | tty->overrun_time = jiffies; |
33f0f88f AC |
3678 | tty->buf.head = tty->buf.tail = NULL; |
3679 | tty_buffer_init(tty); | |
65f27f38 | 3680 | INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); |
33f0f88f | 3681 | init_MUTEX(&tty->buf.pty_sem); |
5785c95b | 3682 | mutex_init(&tty->termios_mutex); |
1da177e4 LT |
3683 | init_waitqueue_head(&tty->write_wait); |
3684 | init_waitqueue_head(&tty->read_wait); | |
65f27f38 | 3685 | INIT_WORK(&tty->hangup_work, do_tty_hangup); |
70522e12 IM |
3686 | mutex_init(&tty->atomic_read_lock); |
3687 | mutex_init(&tty->atomic_write_lock); | |
1da177e4 LT |
3688 | spin_lock_init(&tty->read_lock); |
3689 | INIT_LIST_HEAD(&tty->tty_files); | |
7f1f86a0 | 3690 | INIT_WORK(&tty->SAK_work, do_SAK_work); |
1da177e4 LT |
3691 | } |
3692 | ||
3693 | /* | |
3694 | * The default put_char routine if the driver did not define one. | |
3695 | */ | |
af9b897e | 3696 | |
1da177e4 LT |
3697 | static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) |
3698 | { | |
3699 | tty->driver->write(tty, &ch, 1); | |
3700 | } | |
3701 | ||
7fe845d1 | 3702 | static struct class *tty_class; |
1da177e4 LT |
3703 | |
3704 | /** | |
af9b897e AC |
3705 | * tty_register_device - register a tty device |
3706 | * @driver: the tty driver that describes the tty device | |
3707 | * @index: the index in the tty driver for this tty device | |
3708 | * @device: a struct device that is associated with this tty device. | |
3709 | * This field is optional, if there is no known struct device | |
3710 | * for this tty device it can be set to NULL safely. | |
1da177e4 | 3711 | * |
01107d34 GKH |
3712 | * Returns a pointer to the struct device for this tty device |
3713 | * (or ERR_PTR(-EFOO) on error). | |
1cdcb6b4 | 3714 | * |
af9b897e AC |
3715 | * This call is required to be made to register an individual tty device |
3716 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
3717 | * that bit is not set, this function should not be called by a tty | |
3718 | * driver. | |
3719 | * | |
3720 | * Locking: ?? | |
1da177e4 | 3721 | */ |
af9b897e | 3722 | |
01107d34 GKH |
3723 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
3724 | struct device *device) | |
1da177e4 LT |
3725 | { |
3726 | char name[64]; | |
3727 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; | |
3728 | ||
3729 | if (index >= driver->num) { | |
3730 | printk(KERN_ERR "Attempt to register invalid tty line number " | |
3731 | " (%d).\n", index); | |
1cdcb6b4 | 3732 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
3733 | } |
3734 | ||
1da177e4 LT |
3735 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
3736 | pty_line_name(driver, index, name); | |
3737 | else | |
3738 | tty_line_name(driver, index, name); | |
1cdcb6b4 | 3739 | |
01107d34 | 3740 | return device_create(tty_class, device, dev, name); |
1da177e4 LT |
3741 | } |
3742 | ||
3743 | /** | |
af9b897e AC |
3744 | * tty_unregister_device - unregister a tty device |
3745 | * @driver: the tty driver that describes the tty device | |
3746 | * @index: the index in the tty driver for this tty device | |
1da177e4 | 3747 | * |
af9b897e AC |
3748 | * If a tty device is registered with a call to tty_register_device() then |
3749 | * this function must be called when the tty device is gone. | |
3750 | * | |
3751 | * Locking: ?? | |
1da177e4 | 3752 | */ |
af9b897e | 3753 | |
1da177e4 LT |
3754 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
3755 | { | |
01107d34 | 3756 | device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); |
1da177e4 LT |
3757 | } |
3758 | ||
3759 | EXPORT_SYMBOL(tty_register_device); | |
3760 | EXPORT_SYMBOL(tty_unregister_device); | |
3761 | ||
3762 | struct tty_driver *alloc_tty_driver(int lines) | |
3763 | { | |
3764 | struct tty_driver *driver; | |
3765 | ||
506eb99a | 3766 | driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); |
1da177e4 | 3767 | if (driver) { |
1da177e4 LT |
3768 | driver->magic = TTY_DRIVER_MAGIC; |
3769 | driver->num = lines; | |
3770 | /* later we'll move allocation of tables here */ | |
3771 | } | |
3772 | return driver; | |
3773 | } | |
3774 | ||
3775 | void put_tty_driver(struct tty_driver *driver) | |
3776 | { | |
3777 | kfree(driver); | |
3778 | } | |
3779 | ||
b68e31d0 JD |
3780 | void tty_set_operations(struct tty_driver *driver, |
3781 | const struct tty_operations *op) | |
1da177e4 LT |
3782 | { |
3783 | driver->open = op->open; | |
3784 | driver->close = op->close; | |
3785 | driver->write = op->write; | |
3786 | driver->put_char = op->put_char; | |
3787 | driver->flush_chars = op->flush_chars; | |
3788 | driver->write_room = op->write_room; | |
3789 | driver->chars_in_buffer = op->chars_in_buffer; | |
3790 | driver->ioctl = op->ioctl; | |
e10cc1df | 3791 | driver->compat_ioctl = op->compat_ioctl; |
1da177e4 LT |
3792 | driver->set_termios = op->set_termios; |
3793 | driver->throttle = op->throttle; | |
3794 | driver->unthrottle = op->unthrottle; | |
3795 | driver->stop = op->stop; | |
3796 | driver->start = op->start; | |
3797 | driver->hangup = op->hangup; | |
3798 | driver->break_ctl = op->break_ctl; | |
3799 | driver->flush_buffer = op->flush_buffer; | |
3800 | driver->set_ldisc = op->set_ldisc; | |
3801 | driver->wait_until_sent = op->wait_until_sent; | |
3802 | driver->send_xchar = op->send_xchar; | |
3803 | driver->read_proc = op->read_proc; | |
3804 | driver->write_proc = op->write_proc; | |
3805 | driver->tiocmget = op->tiocmget; | |
3806 | driver->tiocmset = op->tiocmset; | |
3807 | } | |
3808 | ||
3809 | ||
3810 | EXPORT_SYMBOL(alloc_tty_driver); | |
3811 | EXPORT_SYMBOL(put_tty_driver); | |
3812 | EXPORT_SYMBOL(tty_set_operations); | |
3813 | ||
3814 | /* | |
3815 | * Called by a tty driver to register itself. | |
3816 | */ | |
3817 | int tty_register_driver(struct tty_driver *driver) | |
3818 | { | |
3819 | int error; | |
3820 | int i; | |
3821 | dev_t dev; | |
3822 | void **p = NULL; | |
3823 | ||
3824 | if (driver->flags & TTY_DRIVER_INSTALLED) | |
3825 | return 0; | |
3826 | ||
543691a6 AW |
3827 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { |
3828 | p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); | |
1da177e4 LT |
3829 | if (!p) |
3830 | return -ENOMEM; | |
1da177e4 LT |
3831 | } |
3832 | ||
3833 | if (!driver->major) { | |
3834 | error = alloc_chrdev_region(&dev, driver->minor_start, driver->num, | |
e5717c48 | 3835 | driver->name); |
1da177e4 LT |
3836 | if (!error) { |
3837 | driver->major = MAJOR(dev); | |
3838 | driver->minor_start = MINOR(dev); | |
3839 | } | |
3840 | } else { | |
3841 | dev = MKDEV(driver->major, driver->minor_start); | |
e5717c48 | 3842 | error = register_chrdev_region(dev, driver->num, driver->name); |
1da177e4 LT |
3843 | } |
3844 | if (error < 0) { | |
3845 | kfree(p); | |
3846 | return error; | |
3847 | } | |
3848 | ||
3849 | if (p) { | |
3850 | driver->ttys = (struct tty_struct **)p; | |
edc6afc5 AC |
3851 | driver->termios = (struct ktermios **)(p + driver->num); |
3852 | driver->termios_locked = (struct ktermios **)(p + driver->num * 2); | |
1da177e4 LT |
3853 | } else { |
3854 | driver->ttys = NULL; | |
3855 | driver->termios = NULL; | |
3856 | driver->termios_locked = NULL; | |
3857 | } | |
3858 | ||
3859 | cdev_init(&driver->cdev, &tty_fops); | |
3860 | driver->cdev.owner = driver->owner; | |
3861 | error = cdev_add(&driver->cdev, dev, driver->num); | |
3862 | if (error) { | |
1da177e4 LT |
3863 | unregister_chrdev_region(dev, driver->num); |
3864 | driver->ttys = NULL; | |
3865 | driver->termios = driver->termios_locked = NULL; | |
3866 | kfree(p); | |
3867 | return error; | |
3868 | } | |
3869 | ||
3870 | if (!driver->put_char) | |
3871 | driver->put_char = tty_default_put_char; | |
3872 | ||
ca509f69 | 3873 | mutex_lock(&tty_mutex); |
1da177e4 | 3874 | list_add(&driver->tty_drivers, &tty_drivers); |
ca509f69 | 3875 | mutex_unlock(&tty_mutex); |
1da177e4 | 3876 | |
331b8319 | 3877 | if ( !(driver->flags & TTY_DRIVER_DYNAMIC_DEV) ) { |
1da177e4 LT |
3878 | for(i = 0; i < driver->num; i++) |
3879 | tty_register_device(driver, i, NULL); | |
3880 | } | |
3881 | proc_tty_register_driver(driver); | |
3882 | return 0; | |
3883 | } | |
3884 | ||
3885 | EXPORT_SYMBOL(tty_register_driver); | |
3886 | ||
3887 | /* | |
3888 | * Called by a tty driver to unregister itself. | |
3889 | */ | |
3890 | int tty_unregister_driver(struct tty_driver *driver) | |
3891 | { | |
3892 | int i; | |
edc6afc5 | 3893 | struct ktermios *tp; |
1da177e4 LT |
3894 | void *p; |
3895 | ||
3896 | if (driver->refcount) | |
3897 | return -EBUSY; | |
3898 | ||
3899 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
3900 | driver->num); | |
ca509f69 | 3901 | mutex_lock(&tty_mutex); |
1da177e4 | 3902 | list_del(&driver->tty_drivers); |
ca509f69 | 3903 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
3904 | |
3905 | /* | |
3906 | * Free the termios and termios_locked structures because | |
3907 | * we don't want to get memory leaks when modular tty | |
3908 | * drivers are removed from the kernel. | |
3909 | */ | |
3910 | for (i = 0; i < driver->num; i++) { | |
3911 | tp = driver->termios[i]; | |
3912 | if (tp) { | |
3913 | driver->termios[i] = NULL; | |
3914 | kfree(tp); | |
3915 | } | |
3916 | tp = driver->termios_locked[i]; | |
3917 | if (tp) { | |
3918 | driver->termios_locked[i] = NULL; | |
3919 | kfree(tp); | |
3920 | } | |
331b8319 | 3921 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
1da177e4 LT |
3922 | tty_unregister_device(driver, i); |
3923 | } | |
3924 | p = driver->ttys; | |
3925 | proc_tty_unregister_driver(driver); | |
3926 | driver->ttys = NULL; | |
3927 | driver->termios = driver->termios_locked = NULL; | |
3928 | kfree(p); | |
3929 | cdev_del(&driver->cdev); | |
3930 | return 0; | |
3931 | } | |
1da177e4 LT |
3932 | EXPORT_SYMBOL(tty_unregister_driver); |
3933 | ||
24ec839c PZ |
3934 | dev_t tty_devnum(struct tty_struct *tty) |
3935 | { | |
3936 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
3937 | } | |
3938 | EXPORT_SYMBOL(tty_devnum); | |
3939 | ||
3940 | void proc_clear_tty(struct task_struct *p) | |
3941 | { | |
3942 | spin_lock_irq(&p->sighand->siglock); | |
3943 | p->signal->tty = NULL; | |
3944 | spin_unlock_irq(&p->sighand->siglock); | |
3945 | } | |
7cac4ce5 | 3946 | EXPORT_SYMBOL(proc_clear_tty); |
24ec839c | 3947 | |
2a65f1d9 | 3948 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
3949 | { |
3950 | if (tty) { | |
d9c1e9a8 EB |
3951 | /* We should not have a session or pgrp to here but.... */ |
3952 | put_pid(tty->session); | |
3953 | put_pid(tty->pgrp); | |
ab521dc0 EB |
3954 | tty->session = get_pid(task_session(tsk)); |
3955 | tty->pgrp = get_pid(task_pgrp(tsk)); | |
24ec839c | 3956 | } |
2a65f1d9 | 3957 | put_pid(tsk->signal->tty_old_pgrp); |
24ec839c | 3958 | tsk->signal->tty = tty; |
ab521dc0 | 3959 | tsk->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
3960 | } |
3961 | ||
98a27ba4 | 3962 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
3963 | { |
3964 | spin_lock_irq(&tsk->sighand->siglock); | |
2a65f1d9 | 3965 | __proc_set_tty(tsk, tty); |
24ec839c PZ |
3966 | spin_unlock_irq(&tsk->sighand->siglock); |
3967 | } | |
3968 | ||
3969 | struct tty_struct *get_current_tty(void) | |
3970 | { | |
3971 | struct tty_struct *tty; | |
3972 | WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); | |
3973 | tty = current->signal->tty; | |
3974 | /* | |
3975 | * session->tty can be changed/cleared from under us, make sure we | |
3976 | * issue the load. The obtained pointer, when not NULL, is valid as | |
3977 | * long as we hold tty_mutex. | |
3978 | */ | |
3979 | barrier(); | |
3980 | return tty; | |
3981 | } | |
a311f743 | 3982 | EXPORT_SYMBOL_GPL(get_current_tty); |
1da177e4 LT |
3983 | |
3984 | /* | |
3985 | * Initialize the console device. This is called *early*, so | |
3986 | * we can't necessarily depend on lots of kernel help here. | |
3987 | * Just do some early initializations, and do the complex setup | |
3988 | * later. | |
3989 | */ | |
3990 | void __init console_init(void) | |
3991 | { | |
3992 | initcall_t *call; | |
3993 | ||
3994 | /* Setup the default TTY line discipline. */ | |
3995 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); | |
3996 | ||
3997 | /* | |
3998 | * set up the console device so that later boot sequences can | |
3999 | * inform about problems etc.. | |
4000 | */ | |
1da177e4 LT |
4001 | call = __con_initcall_start; |
4002 | while (call < __con_initcall_end) { | |
4003 | (*call)(); | |
4004 | call++; | |
4005 | } | |
4006 | } | |
4007 | ||
4008 | #ifdef CONFIG_VT | |
4009 | extern int vty_init(void); | |
4010 | #endif | |
4011 | ||
4012 | static int __init tty_class_init(void) | |
4013 | { | |
7fe845d1 | 4014 | tty_class = class_create(THIS_MODULE, "tty"); |
1da177e4 LT |
4015 | if (IS_ERR(tty_class)) |
4016 | return PTR_ERR(tty_class); | |
4017 | return 0; | |
4018 | } | |
4019 | ||
4020 | postcore_initcall(tty_class_init); | |
4021 | ||
4022 | /* 3/2004 jmc: why do these devices exist? */ | |
4023 | ||
4024 | static struct cdev tty_cdev, console_cdev; | |
4025 | #ifdef CONFIG_UNIX98_PTYS | |
4026 | static struct cdev ptmx_cdev; | |
4027 | #endif | |
4028 | #ifdef CONFIG_VT | |
4029 | static struct cdev vc0_cdev; | |
4030 | #endif | |
4031 | ||
4032 | /* | |
4033 | * Ok, now we can initialize the rest of the tty devices and can count | |
4034 | * on memory allocations, interrupts etc.. | |
4035 | */ | |
4036 | static int __init tty_init(void) | |
4037 | { | |
4038 | cdev_init(&tty_cdev, &tty_fops); | |
4039 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
4040 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
4041 | panic("Couldn't register /dev/tty driver\n"); | |
01107d34 | 4042 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty"); |
1da177e4 LT |
4043 | |
4044 | cdev_init(&console_cdev, &console_fops); | |
4045 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
4046 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
4047 | panic("Couldn't register /dev/console driver\n"); | |
01107d34 | 4048 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console"); |
1da177e4 LT |
4049 | |
4050 | #ifdef CONFIG_UNIX98_PTYS | |
4051 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
4052 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
4053 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
4054 | panic("Couldn't register /dev/ptmx driver\n"); | |
01107d34 | 4055 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); |
1da177e4 LT |
4056 | #endif |
4057 | ||
4058 | #ifdef CONFIG_VT | |
4059 | cdev_init(&vc0_cdev, &console_fops); | |
4060 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || | |
4061 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) | |
4062 | panic("Couldn't register /dev/tty0 driver\n"); | |
01107d34 | 4063 | device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); |
1da177e4 LT |
4064 | |
4065 | vty_init(); | |
4066 | #endif | |
4067 | return 0; | |
4068 | } | |
4069 | module_init(tty_init); |