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 | |
37bdfb07 | 22 | * makes for cleaner and more compact code. -TYT, 9/17/92 |
1da177e4 LT |
23 | * |
24 | * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines | |
25 | * which can be dynamically activated and de-activated by the line | |
26 | * discipline handling modules (like SLIP). | |
27 | * | |
28 | * NOTE: pay no attention to the line discipline code (yet); its | |
29 | * interface is still subject to change in this version... | |
30 | * -- TYT, 1/31/92 | |
31 | * | |
32 | * Added functionality to the OPOST tty handling. No delays, but all | |
33 | * other bits should be there. | |
34 | * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. | |
35 | * | |
36 | * Rewrote canonical mode and added more termios flags. | |
37 | * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 | |
38 | * | |
39 | * Reorganized FASYNC support so mouse code can share it. | |
40 | * -- ctm@ardi.com, 9Sep95 | |
41 | * | |
42 | * New TIOCLINUX variants added. | |
43 | * -- mj@k332.feld.cvut.cz, 19-Nov-95 | |
37bdfb07 | 44 | * |
1da177e4 LT |
45 | * Restrict vt switching via ioctl() |
46 | * -- grif@cs.ucr.edu, 5-Dec-95 | |
47 | * | |
48 | * Move console and virtual terminal code to more appropriate files, | |
49 | * implement CONFIG_VT and generalize console device interface. | |
50 | * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 | |
51 | * | |
52 | * Rewrote init_dev and release_dev to eliminate races. | |
53 | * -- Bill Hawes <whawes@star.net>, June 97 | |
54 | * | |
55 | * Added devfs support. | |
56 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 | |
57 | * | |
58 | * Added support for a Unix98-style ptmx device. | |
59 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 | |
60 | * | |
61 | * Reduced memory usage for older ARM systems | |
62 | * -- Russell King <rmk@arm.linux.org.uk> | |
63 | * | |
64 | * Move do_SAK() into process context. Less stack use in devfs functions. | |
37bdfb07 AC |
65 | * alloc_tty_struct() always uses kmalloc() |
66 | * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 | |
1da177e4 LT |
67 | */ |
68 | ||
1da177e4 LT |
69 | #include <linux/types.h> |
70 | #include <linux/major.h> | |
71 | #include <linux/errno.h> | |
72 | #include <linux/signal.h> | |
73 | #include <linux/fcntl.h> | |
74 | #include <linux/sched.h> | |
75 | #include <linux/interrupt.h> | |
76 | #include <linux/tty.h> | |
77 | #include <linux/tty_driver.h> | |
78 | #include <linux/tty_flip.h> | |
79 | #include <linux/devpts_fs.h> | |
80 | #include <linux/file.h> | |
9f3acc31 | 81 | #include <linux/fdtable.h> |
1da177e4 LT |
82 | #include <linux/console.h> |
83 | #include <linux/timer.h> | |
84 | #include <linux/ctype.h> | |
85 | #include <linux/kd.h> | |
86 | #include <linux/mm.h> | |
87 | #include <linux/string.h> | |
88 | #include <linux/slab.h> | |
89 | #include <linux/poll.h> | |
90 | #include <linux/proc_fs.h> | |
91 | #include <linux/init.h> | |
92 | #include <linux/module.h> | |
93 | #include <linux/smp_lock.h> | |
94 | #include <linux/device.h> | |
1da177e4 LT |
95 | #include <linux/wait.h> |
96 | #include <linux/bitops.h> | |
b20f3ae5 | 97 | #include <linux/delay.h> |
a352def2 | 98 | #include <linux/seq_file.h> |
1da177e4 | 99 | |
a352def2 | 100 | #include <linux/uaccess.h> |
1da177e4 LT |
101 | #include <asm/system.h> |
102 | ||
103 | #include <linux/kbd_kern.h> | |
104 | #include <linux/vt_kern.h> | |
105 | #include <linux/selection.h> | |
1da177e4 LT |
106 | |
107 | #include <linux/kmod.h> | |
b488893a | 108 | #include <linux/nsproxy.h> |
1da177e4 LT |
109 | |
110 | #undef TTY_DEBUG_HANGUP | |
111 | ||
112 | #define TTY_PARANOIA_CHECK 1 | |
113 | #define CHECK_TTY_COUNT 1 | |
114 | ||
edc6afc5 | 115 | struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ |
1da177e4 LT |
116 | .c_iflag = ICRNL | IXON, |
117 | .c_oflag = OPOST | ONLCR, | |
118 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, | |
119 | .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | | |
120 | ECHOCTL | ECHOKE | IEXTEN, | |
edc6afc5 AC |
121 | .c_cc = INIT_C_CC, |
122 | .c_ispeed = 38400, | |
123 | .c_ospeed = 38400 | |
1da177e4 LT |
124 | }; |
125 | ||
126 | EXPORT_SYMBOL(tty_std_termios); | |
127 | ||
128 | /* This list gets poked at by procfs and various bits of boot up code. This | |
129 | could do with some rationalisation such as pulling the tty proc function | |
130 | into this file */ | |
37bdfb07 | 131 | |
1da177e4 LT |
132 | LIST_HEAD(tty_drivers); /* linked list of tty drivers */ |
133 | ||
24ec839c | 134 | /* Mutex to protect creating and releasing a tty. This is shared with |
1da177e4 | 135 | vt.c for deeply disgusting hack reasons */ |
70522e12 | 136 | DEFINE_MUTEX(tty_mutex); |
de2a84f2 | 137 | EXPORT_SYMBOL(tty_mutex); |
1da177e4 LT |
138 | |
139 | #ifdef CONFIG_UNIX98_PTYS | |
140 | extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ | |
1da177e4 LT |
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 *); | |
37bdfb07 AC |
148 | ssize_t redirected_tty_write(struct file *, const char __user *, |
149 | size_t, loff_t *); | |
1da177e4 LT |
150 | static unsigned int tty_poll(struct file *, poll_table *); |
151 | static int tty_open(struct inode *, struct file *); | |
152 | static int tty_release(struct inode *, struct file *); | |
04f378b1 | 153 | long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg); |
e10cc1df | 154 | #ifdef CONFIG_COMPAT |
37bdfb07 | 155 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
e10cc1df PF |
156 | unsigned long arg); |
157 | #else | |
158 | #define tty_compat_ioctl NULL | |
159 | #endif | |
37bdfb07 | 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; | |
37bdfb07 | 246 | |
1da177e4 LT |
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; | |
37bdfb07 | 283 | while ((thead = tty->buf.head) != NULL) { |
33f0f88f AC |
284 | tty->buf.head = thead->next; |
285 | kfree(thead); | |
286 | } | |
37bdfb07 | 287 | while ((thead = tty->buf.free) != NULL) { |
33f0f88f AC |
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); | |
37bdfb07 | 333 | if (p == NULL) |
33f0f88f AC |
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 | ||
37bdfb07 | 363 | if (b->size >= 512) |
33f0f88f AC |
364 | kfree(b); |
365 | else { | |
366 | b->next = tty->buf.free; | |
367 | tty->buf.free = b; | |
368 | } | |
369 | } | |
370 | ||
c5c34d48 | 371 | /** |
42fd552e | 372 | * __tty_buffer_flush - flush full tty buffers |
c5c34d48 PF |
373 | * @tty: tty to flush |
374 | * | |
42fd552e AC |
375 | * flush all the buffers containing receive data. Caller must |
376 | * hold the buffer lock and must have ensured no parallel flush to | |
377 | * ldisc is running. | |
c5c34d48 | 378 | * |
42fd552e | 379 | * Locking: Caller must hold tty->buf.lock |
c5c34d48 PF |
380 | */ |
381 | ||
42fd552e | 382 | static void __tty_buffer_flush(struct tty_struct *tty) |
c5c34d48 PF |
383 | { |
384 | struct tty_buffer *thead; | |
c5c34d48 | 385 | |
37bdfb07 | 386 | while ((thead = tty->buf.head) != NULL) { |
c5c34d48 PF |
387 | tty->buf.head = thead->next; |
388 | tty_buffer_free(tty, thead); | |
389 | } | |
390 | tty->buf.tail = NULL; | |
42fd552e AC |
391 | } |
392 | ||
393 | /** | |
394 | * tty_buffer_flush - flush full tty buffers | |
395 | * @tty: tty to flush | |
396 | * | |
397 | * flush all the buffers containing receive data. If the buffer is | |
398 | * being processed by flush_to_ldisc then we defer the processing | |
399 | * to that function | |
400 | * | |
401 | * Locking: none | |
402 | */ | |
403 | ||
404 | static void tty_buffer_flush(struct tty_struct *tty) | |
405 | { | |
406 | unsigned long flags; | |
407 | spin_lock_irqsave(&tty->buf.lock, flags); | |
408 | ||
409 | /* If the data is being pushed to the tty layer then we can't | |
410 | process it here. Instead set a flag and the flush_to_ldisc | |
411 | path will process the flush request before it exits */ | |
412 | if (test_bit(TTY_FLUSHING, &tty->flags)) { | |
413 | set_bit(TTY_FLUSHPENDING, &tty->flags); | |
414 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
415 | wait_event(tty->read_wait, | |
416 | test_bit(TTY_FLUSHPENDING, &tty->flags) == 0); | |
417 | return; | |
418 | } else | |
419 | __tty_buffer_flush(tty); | |
c5c34d48 PF |
420 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
421 | } | |
422 | ||
01da5fd8 AC |
423 | /** |
424 | * tty_buffer_find - find a free tty buffer | |
425 | * @tty: tty owning the buffer | |
426 | * @size: characters wanted | |
427 | * | |
428 | * Locate an existing suitable tty buffer or if we are lacking one then | |
429 | * allocate a new one. We round our buffers off in 256 character chunks | |
430 | * to get better allocation behaviour. | |
431 | * | |
432 | * Locking: Caller must hold tty->buf.lock | |
433 | */ | |
434 | ||
33f0f88f AC |
435 | static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) |
436 | { | |
437 | struct tty_buffer **tbh = &tty->buf.free; | |
37bdfb07 | 438 | while ((*tbh) != NULL) { |
33f0f88f | 439 | struct tty_buffer *t = *tbh; |
37bdfb07 | 440 | if (t->size >= size) { |
33f0f88f AC |
441 | *tbh = t->next; |
442 | t->next = NULL; | |
443 | t->used = 0; | |
8977d929 PF |
444 | t->commit = 0; |
445 | t->read = 0; | |
01da5fd8 | 446 | tty->buf.memory_used += t->size; |
33f0f88f AC |
447 | return t; |
448 | } | |
449 | tbh = &((*tbh)->next); | |
450 | } | |
451 | /* Round the buffer size out */ | |
37bdfb07 | 452 | size = (size + 0xFF) & ~0xFF; |
01da5fd8 | 453 | return tty_buffer_alloc(tty, size); |
33f0f88f AC |
454 | /* Should possibly check if this fails for the largest buffer we |
455 | have queued and recycle that ? */ | |
456 | } | |
457 | ||
01da5fd8 AC |
458 | /** |
459 | * tty_buffer_request_room - grow tty buffer if needed | |
460 | * @tty: tty structure | |
461 | * @size: size desired | |
462 | * | |
463 | * Make at least size bytes of linear space available for the tty | |
464 | * buffer. If we fail return the size we managed to find. | |
465 | * | |
466 | * Locking: Takes tty->buf.lock | |
467 | */ | |
33f0f88f AC |
468 | int tty_buffer_request_room(struct tty_struct *tty, size_t size) |
469 | { | |
808249ce PF |
470 | struct tty_buffer *b, *n; |
471 | int left; | |
472 | unsigned long flags; | |
473 | ||
474 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33f0f88f AC |
475 | |
476 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to | |
477 | remove this conditional if its worth it. This would be invisible | |
478 | to the callers */ | |
33b37a33 | 479 | if ((b = tty->buf.tail) != NULL) |
33f0f88f | 480 | left = b->size - b->used; |
33b37a33 | 481 | else |
808249ce PF |
482 | left = 0; |
483 | ||
484 | if (left < size) { | |
485 | /* This is the slow path - looking for new buffers to use */ | |
486 | if ((n = tty_buffer_find(tty, size)) != NULL) { | |
487 | if (b != NULL) { | |
488 | b->next = n; | |
8977d929 | 489 | b->commit = b->used; |
808249ce PF |
490 | } else |
491 | tty->buf.head = n; | |
492 | tty->buf.tail = n; | |
808249ce PF |
493 | } else |
494 | size = left; | |
495 | } | |
496 | ||
497 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
33f0f88f AC |
498 | return size; |
499 | } | |
33f0f88f AC |
500 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
501 | ||
af9b897e AC |
502 | /** |
503 | * tty_insert_flip_string - Add characters to the tty buffer | |
504 | * @tty: tty structure | |
505 | * @chars: characters | |
506 | * @size: size | |
507 | * | |
508 | * Queue a series of bytes to the tty buffering. All the characters | |
509 | * passed are marked as without error. Returns the number added. | |
510 | * | |
511 | * Locking: Called functions may take tty->buf.lock | |
512 | */ | |
513 | ||
e1a25090 AM |
514 | int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, |
515 | size_t size) | |
33f0f88f AC |
516 | { |
517 | int copied = 0; | |
518 | do { | |
519 | int space = tty_buffer_request_room(tty, size - copied); | |
520 | struct tty_buffer *tb = tty->buf.tail; | |
521 | /* If there is no space then tb may be NULL */ | |
37bdfb07 | 522 | if (unlikely(space == 0)) |
33f0f88f AC |
523 | break; |
524 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
525 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
526 | tb->used += space; | |
527 | copied += space; | |
528 | chars += space; | |
527063ba AD |
529 | /* There is a small chance that we need to split the data over |
530 | several buffers. If this is the case we must loop */ | |
531 | } while (unlikely(size > copied)); | |
33f0f88f AC |
532 | return copied; |
533 | } | |
ee37df78 | 534 | EXPORT_SYMBOL(tty_insert_flip_string); |
33f0f88f | 535 | |
af9b897e AC |
536 | /** |
537 | * tty_insert_flip_string_flags - Add characters to the tty buffer | |
538 | * @tty: tty structure | |
539 | * @chars: characters | |
540 | * @flags: flag bytes | |
541 | * @size: size | |
542 | * | |
543 | * Queue a series of bytes to the tty buffering. For each character | |
544 | * the flags array indicates the status of the character. Returns the | |
545 | * number added. | |
546 | * | |
547 | * Locking: Called functions may take tty->buf.lock | |
548 | */ | |
549 | ||
e1a25090 AM |
550 | int tty_insert_flip_string_flags(struct tty_struct *tty, |
551 | const unsigned char *chars, const char *flags, size_t size) | |
33f0f88f AC |
552 | { |
553 | int copied = 0; | |
554 | do { | |
555 | int space = tty_buffer_request_room(tty, size - copied); | |
556 | struct tty_buffer *tb = tty->buf.tail; | |
557 | /* If there is no space then tb may be NULL */ | |
37bdfb07 | 558 | if (unlikely(space == 0)) |
33f0f88f AC |
559 | break; |
560 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
561 | memcpy(tb->flag_buf_ptr + tb->used, flags, space); | |
562 | tb->used += space; | |
563 | copied += space; | |
564 | chars += space; | |
565 | flags += space; | |
527063ba AD |
566 | /* There is a small chance that we need to split the data over |
567 | several buffers. If this is the case we must loop */ | |
568 | } while (unlikely(size > copied)); | |
33f0f88f AC |
569 | return copied; |
570 | } | |
ff4547f4 | 571 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
33f0f88f | 572 | |
af9b897e AC |
573 | /** |
574 | * tty_schedule_flip - push characters to ldisc | |
575 | * @tty: tty to push from | |
576 | * | |
577 | * Takes any pending buffers and transfers their ownership to the | |
578 | * ldisc side of the queue. It then schedules those characters for | |
579 | * processing by the line discipline. | |
580 | * | |
581 | * Locking: Takes tty->buf.lock | |
582 | */ | |
583 | ||
e1a25090 AM |
584 | void tty_schedule_flip(struct tty_struct *tty) |
585 | { | |
586 | unsigned long flags; | |
587 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 588 | if (tty->buf.tail != NULL) |
e1a25090 | 589 | tty->buf.tail->commit = tty->buf.tail->used; |
e1a25090 AM |
590 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
591 | schedule_delayed_work(&tty->buf.work, 1); | |
592 | } | |
593 | EXPORT_SYMBOL(tty_schedule_flip); | |
33f0f88f | 594 | |
af9b897e AC |
595 | /** |
596 | * tty_prepare_flip_string - make room for characters | |
597 | * @tty: tty | |
598 | * @chars: return pointer for character write area | |
599 | * @size: desired size | |
600 | * | |
33f0f88f AC |
601 | * Prepare a block of space in the buffer for data. Returns the length |
602 | * available and buffer pointer to the space which is now allocated and | |
603 | * accounted for as ready for normal characters. This is used for drivers | |
604 | * that need their own block copy routines into the buffer. There is no | |
605 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
606 | * |
607 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
608 | */ |
609 | ||
37bdfb07 AC |
610 | int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, |
611 | size_t size) | |
33f0f88f AC |
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 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
618 | tb->used += space; | |
619 | } | |
33f0f88f AC |
620 | return space; |
621 | } | |
622 | ||
623 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); | |
624 | ||
af9b897e AC |
625 | /** |
626 | * tty_prepare_flip_string_flags - make room for characters | |
627 | * @tty: tty | |
628 | * @chars: return pointer for character write area | |
629 | * @flags: return pointer for status flag write area | |
630 | * @size: desired size | |
631 | * | |
33f0f88f AC |
632 | * Prepare a block of space in the buffer for data. Returns the length |
633 | * available and buffer pointer to the space which is now allocated and | |
634 | * accounted for as ready for characters. This is used for drivers | |
635 | * that need their own block copy routines into the buffer. There is no | |
636 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
637 | * |
638 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
639 | */ |
640 | ||
37bdfb07 AC |
641 | int tty_prepare_flip_string_flags(struct tty_struct *tty, |
642 | unsigned char **chars, char **flags, size_t size) | |
33f0f88f AC |
643 | { |
644 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
645 | if (likely(space)) { |
646 | struct tty_buffer *tb = tty->buf.tail; | |
647 | *chars = tb->char_buf_ptr + tb->used; | |
648 | *flags = tb->flag_buf_ptr + tb->used; | |
649 | tb->used += space; | |
650 | } | |
33f0f88f AC |
651 | return space; |
652 | } | |
653 | ||
654 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); | |
655 | ||
656 | ||
657 | ||
af9b897e AC |
658 | /** |
659 | * tty_set_termios_ldisc - set ldisc field | |
660 | * @tty: tty structure | |
661 | * @num: line discipline number | |
662 | * | |
1da177e4 | 663 | * This is probably overkill for real world processors but |
37bdfb07 | 664 | * they are not on hot paths so a little discipline won't do |
1da177e4 | 665 | * any harm. |
af9b897e | 666 | * |
24ec839c | 667 | * Locking: takes termios_mutex |
1da177e4 | 668 | */ |
37bdfb07 | 669 | |
1da177e4 LT |
670 | static void tty_set_termios_ldisc(struct tty_struct *tty, int num) |
671 | { | |
5785c95b | 672 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 673 | tty->termios->c_line = num; |
5785c95b | 674 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
675 | } |
676 | ||
677 | /* | |
678 | * This guards the refcounted line discipline lists. The lock | |
679 | * must be taken with irqs off because there are hangup path | |
680 | * callers who will do ldisc lookups and cannot sleep. | |
681 | */ | |
37bdfb07 | 682 | |
1da177e4 LT |
683 | static DEFINE_SPINLOCK(tty_ldisc_lock); |
684 | static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); | |
37bdfb07 | 685 | /* Line disc dispatch table */ |
a352def2 | 686 | static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS]; |
1da177e4 | 687 | |
af9b897e AC |
688 | /** |
689 | * tty_register_ldisc - install a line discipline | |
690 | * @disc: ldisc number | |
691 | * @new_ldisc: pointer to the ldisc object | |
692 | * | |
693 | * Installs a new line discipline into the kernel. The discipline | |
694 | * is set up as unreferenced and then made available to the kernel | |
695 | * from this point onwards. | |
696 | * | |
697 | * Locking: | |
698 | * takes tty_ldisc_lock to guard against ldisc races | |
699 | */ | |
700 | ||
a352def2 | 701 | int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc) |
1da177e4 LT |
702 | { |
703 | unsigned long flags; | |
704 | int ret = 0; | |
37bdfb07 | 705 | |
1da177e4 LT |
706 | if (disc < N_TTY || disc >= NR_LDISCS) |
707 | return -EINVAL; | |
37bdfb07 | 708 | |
1da177e4 | 709 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
a352def2 AC |
710 | tty_ldiscs[disc] = new_ldisc; |
711 | new_ldisc->num = disc; | |
712 | new_ldisc->refcount = 0; | |
1da177e4 | 713 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
37bdfb07 | 714 | |
1da177e4 LT |
715 | return ret; |
716 | } | |
1da177e4 LT |
717 | EXPORT_SYMBOL(tty_register_ldisc); |
718 | ||
af9b897e AC |
719 | /** |
720 | * tty_unregister_ldisc - unload a line discipline | |
721 | * @disc: ldisc number | |
722 | * @new_ldisc: pointer to the ldisc object | |
723 | * | |
724 | * Remove a line discipline from the kernel providing it is not | |
725 | * currently in use. | |
726 | * | |
727 | * Locking: | |
728 | * takes tty_ldisc_lock to guard against ldisc races | |
729 | */ | |
730 | ||
bfb07599 AD |
731 | int tty_unregister_ldisc(int disc) |
732 | { | |
733 | unsigned long flags; | |
734 | int ret = 0; | |
735 | ||
736 | if (disc < N_TTY || disc >= NR_LDISCS) | |
737 | return -EINVAL; | |
738 | ||
739 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
a352def2 | 740 | if (tty_ldiscs[disc]->refcount) |
bfb07599 AD |
741 | ret = -EBUSY; |
742 | else | |
a352def2 | 743 | tty_ldiscs[disc] = NULL; |
bfb07599 AD |
744 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
745 | ||
746 | return ret; | |
747 | } | |
748 | EXPORT_SYMBOL(tty_unregister_ldisc); | |
749 | ||
a352def2 AC |
750 | |
751 | /** | |
752 | * tty_ldisc_try_get - try and reference an ldisc | |
753 | * @disc: ldisc number | |
754 | * @ld: tty ldisc structure to complete | |
755 | * | |
756 | * Attempt to open and lock a line discipline into place. Return | |
757 | * the line discipline refcounted and assigned in ld. On an error | |
758 | * report the error code back | |
759 | */ | |
760 | ||
761 | static int tty_ldisc_try_get(int disc, struct tty_ldisc *ld) | |
762 | { | |
763 | unsigned long flags; | |
764 | struct tty_ldisc_ops *ldops; | |
765 | int err = -EINVAL; | |
766 | ||
767 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
768 | ld->ops = NULL; | |
769 | ldops = tty_ldiscs[disc]; | |
770 | /* Check the entry is defined */ | |
771 | if (ldops) { | |
772 | /* If the module is being unloaded we can't use it */ | |
773 | if (!try_module_get(ldops->owner)) | |
774 | err = -EAGAIN; | |
775 | else { | |
776 | /* lock it */ | |
777 | ldops->refcount++; | |
778 | ld->ops = ldops; | |
779 | err = 0; | |
780 | } | |
781 | } | |
782 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
783 | return err; | |
784 | } | |
785 | ||
af9b897e AC |
786 | /** |
787 | * tty_ldisc_get - take a reference to an ldisc | |
788 | * @disc: ldisc number | |
a352def2 | 789 | * @ld: tty line discipline structure to use |
af9b897e AC |
790 | * |
791 | * Takes a reference to a line discipline. Deals with refcounts and | |
792 | * module locking counts. Returns NULL if the discipline is not available. | |
793 | * Returns a pointer to the discipline and bumps the ref count if it is | |
794 | * available | |
795 | * | |
796 | * Locking: | |
797 | * takes tty_ldisc_lock to guard against ldisc races | |
798 | */ | |
799 | ||
a352def2 | 800 | static int tty_ldisc_get(int disc, struct tty_ldisc *ld) |
1da177e4 | 801 | { |
a352def2 | 802 | int err; |
1da177e4 LT |
803 | |
804 | if (disc < N_TTY || disc >= NR_LDISCS) | |
a352def2 AC |
805 | return -EINVAL; |
806 | err = tty_ldisc_try_get(disc, ld); | |
807 | if (err == -EAGAIN) { | |
808 | request_module("tty-ldisc-%d", disc); | |
809 | err = tty_ldisc_try_get(disc, ld); | |
810 | } | |
811 | return err; | |
1da177e4 LT |
812 | } |
813 | ||
af9b897e AC |
814 | /** |
815 | * tty_ldisc_put - drop ldisc reference | |
816 | * @disc: ldisc number | |
817 | * | |
818 | * Drop a reference to a line discipline. Manage refcounts and | |
819 | * module usage counts | |
820 | * | |
821 | * Locking: | |
822 | * takes tty_ldisc_lock to guard against ldisc races | |
823 | */ | |
824 | ||
a352def2 | 825 | static void tty_ldisc_put(struct tty_ldisc_ops *ld) |
1da177e4 | 826 | { |
1da177e4 | 827 | unsigned long flags; |
a352def2 | 828 | int disc = ld->num; |
37bdfb07 | 829 | |
56ee4827 | 830 | BUG_ON(disc < N_TTY || disc >= NR_LDISCS); |
37bdfb07 | 831 | |
1da177e4 | 832 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
a352def2 | 833 | ld = tty_ldiscs[disc]; |
56ee4827 ES |
834 | BUG_ON(ld->refcount == 0); |
835 | ld->refcount--; | |
1da177e4 LT |
836 | module_put(ld->owner); |
837 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
838 | } | |
37bdfb07 | 839 | |
a352def2 AC |
840 | static void * tty_ldiscs_seq_start(struct seq_file *m, loff_t *pos) |
841 | { | |
842 | return (*pos < NR_LDISCS) ? pos : NULL; | |
843 | } | |
844 | ||
845 | static void * tty_ldiscs_seq_next(struct seq_file *m, void *v, loff_t *pos) | |
846 | { | |
847 | (*pos)++; | |
848 | return (*pos < NR_LDISCS) ? pos : NULL; | |
849 | } | |
850 | ||
851 | static void tty_ldiscs_seq_stop(struct seq_file *m, void *v) | |
852 | { | |
853 | } | |
854 | ||
855 | static int tty_ldiscs_seq_show(struct seq_file *m, void *v) | |
856 | { | |
857 | int i = *(loff_t *)v; | |
858 | struct tty_ldisc ld; | |
859 | ||
860 | if (tty_ldisc_get(i, &ld) < 0) | |
861 | return 0; | |
862 | seq_printf(m, "%-10s %2d\n", ld.ops->name ? ld.ops->name : "???", i); | |
863 | tty_ldisc_put(ld.ops); | |
864 | return 0; | |
865 | } | |
866 | ||
867 | static const struct seq_operations tty_ldiscs_seq_ops = { | |
868 | .start = tty_ldiscs_seq_start, | |
869 | .next = tty_ldiscs_seq_next, | |
870 | .stop = tty_ldiscs_seq_stop, | |
871 | .show = tty_ldiscs_seq_show, | |
872 | }; | |
873 | ||
874 | static int proc_tty_ldiscs_open(struct inode *inode, struct file *file) | |
875 | { | |
876 | return seq_open(file, &tty_ldiscs_seq_ops); | |
877 | } | |
878 | ||
879 | const struct file_operations tty_ldiscs_proc_fops = { | |
880 | .owner = THIS_MODULE, | |
881 | .open = proc_tty_ldiscs_open, | |
882 | .read = seq_read, | |
883 | .llseek = seq_lseek, | |
884 | .release = seq_release, | |
885 | }; | |
1da177e4 | 886 | |
af9b897e AC |
887 | /** |
888 | * tty_ldisc_assign - set ldisc on a tty | |
889 | * @tty: tty to assign | |
890 | * @ld: line discipline | |
891 | * | |
892 | * Install an instance of a line discipline into a tty structure. The | |
893 | * ldisc must have a reference count above zero to ensure it remains/ | |
894 | * The tty instance refcount starts at zero. | |
895 | * | |
896 | * Locking: | |
897 | * Caller must hold references | |
898 | */ | |
899 | ||
1da177e4 LT |
900 | static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) |
901 | { | |
a352def2 | 902 | ld->refcount = 0; |
1da177e4 | 903 | tty->ldisc = *ld; |
1da177e4 LT |
904 | } |
905 | ||
906 | /** | |
907 | * tty_ldisc_try - internal helper | |
908 | * @tty: the tty | |
909 | * | |
910 | * Make a single attempt to grab and bump the refcount on | |
911 | * the tty ldisc. Return 0 on failure or 1 on success. This is | |
912 | * used to implement both the waiting and non waiting versions | |
913 | * of tty_ldisc_ref | |
af9b897e AC |
914 | * |
915 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
916 | */ |
917 | ||
918 | static int tty_ldisc_try(struct tty_struct *tty) | |
919 | { | |
920 | unsigned long flags; | |
921 | struct tty_ldisc *ld; | |
922 | int ret = 0; | |
37bdfb07 | 923 | |
1da177e4 LT |
924 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
925 | ld = &tty->ldisc; | |
37bdfb07 | 926 | if (test_bit(TTY_LDISC, &tty->flags)) { |
1da177e4 LT |
927 | ld->refcount++; |
928 | ret = 1; | |
929 | } | |
930 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
931 | return ret; | |
932 | } | |
933 | ||
934 | /** | |
935 | * tty_ldisc_ref_wait - wait for the tty ldisc | |
936 | * @tty: tty device | |
937 | * | |
37bdfb07 AC |
938 | * Dereference the line discipline for the terminal and take a |
939 | * reference to it. If the line discipline is in flux then | |
1da177e4 LT |
940 | * wait patiently until it changes. |
941 | * | |
942 | * Note: Must not be called from an IRQ/timer context. The caller | |
943 | * must also be careful not to hold other locks that will deadlock | |
944 | * against a discipline change, such as an existing ldisc reference | |
945 | * (which we check for) | |
af9b897e AC |
946 | * |
947 | * Locking: call functions take tty_ldisc_lock | |
1da177e4 | 948 | */ |
37bdfb07 | 949 | |
1da177e4 LT |
950 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) |
951 | { | |
952 | /* wait_event is a macro */ | |
953 | wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); | |
37bdfb07 | 954 | if (tty->ldisc.refcount == 0) |
1da177e4 LT |
955 | printk(KERN_ERR "tty_ldisc_ref_wait\n"); |
956 | return &tty->ldisc; | |
957 | } | |
958 | ||
959 | EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); | |
960 | ||
961 | /** | |
962 | * tty_ldisc_ref - get the tty ldisc | |
963 | * @tty: tty device | |
964 | * | |
37bdfb07 AC |
965 | * Dereference the line discipline for the terminal and take a |
966 | * reference to it. If the line discipline is in flux then | |
1da177e4 | 967 | * return NULL. Can be called from IRQ and timer functions. |
af9b897e AC |
968 | * |
969 | * Locking: called functions take tty_ldisc_lock | |
1da177e4 | 970 | */ |
37bdfb07 | 971 | |
1da177e4 LT |
972 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) |
973 | { | |
37bdfb07 | 974 | if (tty_ldisc_try(tty)) |
1da177e4 LT |
975 | return &tty->ldisc; |
976 | return NULL; | |
977 | } | |
978 | ||
979 | EXPORT_SYMBOL_GPL(tty_ldisc_ref); | |
980 | ||
981 | /** | |
982 | * tty_ldisc_deref - free a tty ldisc reference | |
983 | * @ld: reference to free up | |
984 | * | |
985 | * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May | |
986 | * be called in IRQ context. | |
af9b897e AC |
987 | * |
988 | * Locking: takes tty_ldisc_lock | |
1da177e4 | 989 | */ |
37bdfb07 | 990 | |
1da177e4 LT |
991 | void tty_ldisc_deref(struct tty_ldisc *ld) |
992 | { | |
993 | unsigned long flags; | |
994 | ||
56ee4827 | 995 | BUG_ON(ld == NULL); |
37bdfb07 | 996 | |
1da177e4 | 997 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
37bdfb07 | 998 | if (ld->refcount == 0) |
1da177e4 LT |
999 | printk(KERN_ERR "tty_ldisc_deref: no references.\n"); |
1000 | else | |
1001 | ld->refcount--; | |
37bdfb07 | 1002 | if (ld->refcount == 0) |
1da177e4 LT |
1003 | wake_up(&tty_ldisc_wait); |
1004 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
1005 | } | |
1006 | ||
1007 | EXPORT_SYMBOL_GPL(tty_ldisc_deref); | |
1008 | ||
1009 | /** | |
1010 | * tty_ldisc_enable - allow ldisc use | |
1011 | * @tty: terminal to activate ldisc on | |
1012 | * | |
1013 | * Set the TTY_LDISC flag when the line discipline can be called | |
3a4fa0a2 | 1014 | * again. Do necessary wakeups for existing sleepers. |
1da177e4 LT |
1015 | * |
1016 | * Note: nobody should set this bit except via this function. Clearing | |
1017 | * directly is allowed. | |
1018 | */ | |
1019 | ||
1020 | static void tty_ldisc_enable(struct tty_struct *tty) | |
1021 | { | |
1022 | set_bit(TTY_LDISC, &tty->flags); | |
1023 | wake_up(&tty_ldisc_wait); | |
1024 | } | |
37bdfb07 | 1025 | |
a352def2 AC |
1026 | /** |
1027 | * tty_ldisc_restore - helper for tty ldisc change | |
1028 | * @tty: tty to recover | |
1029 | * @old: previous ldisc | |
1030 | * | |
1031 | * Restore the previous line discipline or N_TTY when a line discipline | |
1032 | * change fails due to an open error | |
1033 | */ | |
1034 | ||
1035 | static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old) | |
1036 | { | |
1037 | char buf[64]; | |
1038 | struct tty_ldisc new_ldisc; | |
1039 | ||
1040 | /* There is an outstanding reference here so this is safe */ | |
1041 | tty_ldisc_get(old->ops->num, old); | |
1042 | tty_ldisc_assign(tty, old); | |
1043 | tty_set_termios_ldisc(tty, old->ops->num); | |
1044 | if (old->ops->open && (old->ops->open(tty) < 0)) { | |
1045 | tty_ldisc_put(old->ops); | |
1046 | /* This driver is always present */ | |
1047 | if (tty_ldisc_get(N_TTY, &new_ldisc) < 0) | |
1048 | panic("n_tty: get"); | |
1049 | tty_ldisc_assign(tty, &new_ldisc); | |
1050 | tty_set_termios_ldisc(tty, N_TTY); | |
1051 | if (new_ldisc.ops->open) { | |
1052 | int r = new_ldisc.ops->open(tty); | |
1053 | if (r < 0) | |
1054 | panic("Couldn't open N_TTY ldisc for " | |
1055 | "%s --- error %d.", | |
1056 | tty_name(tty, buf), r); | |
1057 | } | |
1058 | } | |
1059 | } | |
1060 | ||
1da177e4 LT |
1061 | /** |
1062 | * tty_set_ldisc - set line discipline | |
1063 | * @tty: the terminal to set | |
1064 | * @ldisc: the line discipline | |
1065 | * | |
1066 | * Set the discipline of a tty line. Must be called from a process | |
1067 | * context. | |
af9b897e AC |
1068 | * |
1069 | * Locking: takes tty_ldisc_lock. | |
24ec839c | 1070 | * called functions take termios_mutex |
1da177e4 | 1071 | */ |
37bdfb07 | 1072 | |
1da177e4 LT |
1073 | static int tty_set_ldisc(struct tty_struct *tty, int ldisc) |
1074 | { | |
a352def2 AC |
1075 | int retval; |
1076 | struct tty_ldisc o_ldisc, new_ldisc; | |
1da177e4 LT |
1077 | int work; |
1078 | unsigned long flags; | |
ff55fe20 | 1079 | struct tty_struct *o_tty; |
1da177e4 | 1080 | |
1da177e4 | 1081 | restart: |
a352def2 AC |
1082 | /* This is a bit ugly for now but means we can break the 'ldisc |
1083 | is part of the tty struct' assumption later */ | |
1084 | retval = tty_ldisc_get(ldisc, &new_ldisc); | |
1085 | if (retval) | |
1086 | return retval; | |
1da177e4 | 1087 | |
33f0f88f AC |
1088 | /* |
1089 | * Problem: What do we do if this blocks ? | |
1090 | */ | |
1091 | ||
1da177e4 LT |
1092 | tty_wait_until_sent(tty, 0); |
1093 | ||
a352def2 AC |
1094 | if (tty->ldisc.ops->num == ldisc) { |
1095 | tty_ldisc_put(new_ldisc.ops); | |
ff55fe20 JB |
1096 | return 0; |
1097 | } | |
1098 | ||
ae030e43 PF |
1099 | /* |
1100 | * No more input please, we are switching. The new ldisc | |
1101 | * will update this value in the ldisc open function | |
1102 | */ | |
1103 | ||
1104 | tty->receive_room = 0; | |
1105 | ||
ff55fe20 JB |
1106 | o_ldisc = tty->ldisc; |
1107 | o_tty = tty->link; | |
1108 | ||
1da177e4 LT |
1109 | /* |
1110 | * Make sure we don't change while someone holds a | |
1111 | * reference to the line discipline. The TTY_LDISC bit | |
1112 | * prevents anyone taking a reference once it is clear. | |
1113 | * We need the lock to avoid racing reference takers. | |
1114 | */ | |
ff55fe20 | 1115 | |
1da177e4 | 1116 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
ff55fe20 | 1117 | if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { |
37bdfb07 | 1118 | if (tty->ldisc.refcount) { |
ff55fe20 JB |
1119 | /* Free the new ldisc we grabbed. Must drop the lock |
1120 | first. */ | |
1121 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
a352def2 | 1122 | tty_ldisc_put(o_ldisc.ops); |
ff55fe20 JB |
1123 | /* |
1124 | * There are several reasons we may be busy, including | |
1125 | * random momentary I/O traffic. We must therefore | |
1126 | * retry. We could distinguish between blocking ops | |
37bdfb07 AC |
1127 | * and retries if we made tty_ldisc_wait() smarter. |
1128 | * That is up for discussion. | |
ff55fe20 JB |
1129 | */ |
1130 | if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) | |
1131 | return -ERESTARTSYS; | |
1132 | goto restart; | |
1133 | } | |
37bdfb07 | 1134 | if (o_tty && o_tty->ldisc.refcount) { |
ff55fe20 | 1135 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
a352def2 | 1136 | tty_ldisc_put(o_tty->ldisc.ops); |
ff55fe20 JB |
1137 | if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) |
1138 | return -ERESTARTSYS; | |
1139 | goto restart; | |
1140 | } | |
1141 | } | |
37bdfb07 AC |
1142 | /* |
1143 | * If the TTY_LDISC bit is set, then we are racing against | |
1144 | * another ldisc change | |
1145 | */ | |
ff55fe20 | 1146 | if (!test_bit(TTY_LDISC, &tty->flags)) { |
a352def2 | 1147 | struct tty_ldisc *ld; |
1da177e4 | 1148 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
a352def2 | 1149 | tty_ldisc_put(new_ldisc.ops); |
ff55fe20 JB |
1150 | ld = tty_ldisc_ref_wait(tty); |
1151 | tty_ldisc_deref(ld); | |
1da177e4 LT |
1152 | goto restart; |
1153 | } | |
ff55fe20 JB |
1154 | |
1155 | clear_bit(TTY_LDISC, &tty->flags); | |
817d6d3b | 1156 | if (o_tty) |
ff55fe20 | 1157 | clear_bit(TTY_LDISC, &o_tty->flags); |
1da177e4 | 1158 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
a352def2 | 1159 | |
1da177e4 LT |
1160 | /* |
1161 | * From this point on we know nobody has an ldisc | |
1162 | * usage reference, nor can they obtain one until | |
1163 | * we say so later on. | |
1164 | */ | |
ff55fe20 | 1165 | |
33f0f88f | 1166 | work = cancel_delayed_work(&tty->buf.work); |
1da177e4 | 1167 | /* |
33f0f88f | 1168 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
a352def2 | 1169 | * MUST NOT hold locks here. |
1da177e4 | 1170 | */ |
1da177e4 LT |
1171 | flush_scheduled_work(); |
1172 | /* Shutdown the current discipline. */ | |
a352def2 AC |
1173 | if (o_ldisc.ops->close) |
1174 | (o_ldisc.ops->close)(tty); | |
1da177e4 LT |
1175 | |
1176 | /* Now set up the new line discipline. */ | |
a352def2 | 1177 | tty_ldisc_assign(tty, &new_ldisc); |
1da177e4 | 1178 | tty_set_termios_ldisc(tty, ldisc); |
a352def2 AC |
1179 | if (new_ldisc.ops->open) |
1180 | retval = (new_ldisc.ops->open)(tty); | |
1da177e4 | 1181 | if (retval < 0) { |
a352def2 AC |
1182 | tty_ldisc_put(new_ldisc.ops); |
1183 | tty_ldisc_restore(tty, &o_ldisc); | |
1da177e4 LT |
1184 | } |
1185 | /* At this point we hold a reference to the new ldisc and a | |
1186 | a reference to the old ldisc. If we ended up flipping back | |
1187 | to the existing ldisc we have two references to it */ | |
37bdfb07 | 1188 | |
a352def2 | 1189 | if (tty->ldisc.ops->num != o_ldisc.ops->num && tty->ops->set_ldisc) |
f34d7a5b | 1190 | tty->ops->set_ldisc(tty); |
37bdfb07 | 1191 | |
a352def2 | 1192 | tty_ldisc_put(o_ldisc.ops); |
37bdfb07 | 1193 | |
1da177e4 LT |
1194 | /* |
1195 | * Allow ldisc referencing to occur as soon as the driver | |
1196 | * ldisc callback completes. | |
1197 | */ | |
37bdfb07 | 1198 | |
1da177e4 | 1199 | tty_ldisc_enable(tty); |
ff55fe20 JB |
1200 | if (o_tty) |
1201 | tty_ldisc_enable(o_tty); | |
37bdfb07 | 1202 | |
1da177e4 LT |
1203 | /* Restart it in case no characters kick it off. Safe if |
1204 | already running */ | |
ff55fe20 | 1205 | if (work) |
33f0f88f | 1206 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
1207 | return retval; |
1208 | } | |
1209 | ||
af9b897e AC |
1210 | /** |
1211 | * get_tty_driver - find device of a tty | |
1212 | * @dev_t: device identifier | |
1213 | * @index: returns the index of the tty | |
1214 | * | |
1215 | * This routine returns a tty driver structure, given a device number | |
1216 | * and also passes back the index number. | |
1217 | * | |
1218 | * Locking: caller must hold tty_mutex | |
1da177e4 | 1219 | */ |
af9b897e | 1220 | |
1da177e4 LT |
1221 | static struct tty_driver *get_tty_driver(dev_t device, int *index) |
1222 | { | |
1223 | struct tty_driver *p; | |
1224 | ||
1225 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1226 | dev_t base = MKDEV(p->major, p->minor_start); | |
1227 | if (device < base || device >= base + p->num) | |
1228 | continue; | |
1229 | *index = device - base; | |
1230 | return p; | |
1231 | } | |
1232 | return NULL; | |
1233 | } | |
1234 | ||
f2d937f3 JW |
1235 | #ifdef CONFIG_CONSOLE_POLL |
1236 | ||
1237 | /** | |
1238 | * tty_find_polling_driver - find device of a polled tty | |
1239 | * @name: name string to match | |
1240 | * @line: pointer to resulting tty line nr | |
1241 | * | |
1242 | * This routine returns a tty driver structure, given a name | |
1243 | * and the condition that the tty driver is capable of polled | |
1244 | * operation. | |
1245 | */ | |
1246 | struct tty_driver *tty_find_polling_driver(char *name, int *line) | |
1247 | { | |
1248 | struct tty_driver *p, *res = NULL; | |
1249 | int tty_line = 0; | |
1250 | char *str; | |
1251 | ||
1252 | mutex_lock(&tty_mutex); | |
1253 | /* Search through the tty devices to look for a match */ | |
1254 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1255 | str = name + strlen(p->name); | |
1256 | tty_line = simple_strtoul(str, &str, 10); | |
1257 | if (*str == ',') | |
1258 | str++; | |
1259 | if (*str == '\0') | |
8da56309 | 1260 | str = NULL; |
f2d937f3 | 1261 | |
f34d7a5b AC |
1262 | if (tty_line >= 0 && tty_line <= p->num && p->ops && |
1263 | p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) { | |
f2d937f3 JW |
1264 | res = p; |
1265 | *line = tty_line; | |
1266 | break; | |
1267 | } | |
1268 | } | |
1269 | mutex_unlock(&tty_mutex); | |
1270 | ||
1271 | return res; | |
1272 | } | |
1273 | EXPORT_SYMBOL_GPL(tty_find_polling_driver); | |
1274 | #endif | |
1275 | ||
af9b897e AC |
1276 | /** |
1277 | * tty_check_change - check for POSIX terminal changes | |
1278 | * @tty: tty to check | |
1279 | * | |
1280 | * If we try to write to, or set the state of, a terminal and we're | |
1281 | * not in the foreground, send a SIGTTOU. If the signal is blocked or | |
1282 | * ignored, go ahead and perform the operation. (POSIX 7.2) | |
1283 | * | |
978e595f | 1284 | * Locking: ctrl_lock |
1da177e4 | 1285 | */ |
af9b897e | 1286 | |
37bdfb07 | 1287 | int tty_check_change(struct tty_struct *tty) |
1da177e4 | 1288 | { |
47f86834 AC |
1289 | unsigned long flags; |
1290 | int ret = 0; | |
1291 | ||
1da177e4 LT |
1292 | if (current->signal->tty != tty) |
1293 | return 0; | |
47f86834 AC |
1294 | |
1295 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
1296 | ||
ab521dc0 EB |
1297 | if (!tty->pgrp) { |
1298 | printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n"); | |
9ffee4cb | 1299 | goto out_unlock; |
1da177e4 | 1300 | } |
ab521dc0 | 1301 | if (task_pgrp(current) == tty->pgrp) |
9ffee4cb AM |
1302 | goto out_unlock; |
1303 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
1da177e4 | 1304 | if (is_ignored(SIGTTOU)) |
47f86834 AC |
1305 | goto out; |
1306 | if (is_current_pgrp_orphaned()) { | |
1307 | ret = -EIO; | |
1308 | goto out; | |
1309 | } | |
040b6362 ON |
1310 | kill_pgrp(task_pgrp(current), SIGTTOU, 1); |
1311 | set_thread_flag(TIF_SIGPENDING); | |
47f86834 AC |
1312 | ret = -ERESTARTSYS; |
1313 | out: | |
9ffee4cb AM |
1314 | return ret; |
1315 | out_unlock: | |
47f86834 AC |
1316 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1317 | return ret; | |
1da177e4 LT |
1318 | } |
1319 | ||
1320 | EXPORT_SYMBOL(tty_check_change); | |
1321 | ||
37bdfb07 | 1322 | static ssize_t hung_up_tty_read(struct file *file, char __user *buf, |
1da177e4 LT |
1323 | size_t count, loff_t *ppos) |
1324 | { | |
1325 | return 0; | |
1326 | } | |
1327 | ||
37bdfb07 | 1328 | static ssize_t hung_up_tty_write(struct file *file, const char __user *buf, |
1da177e4 LT |
1329 | size_t count, loff_t *ppos) |
1330 | { | |
1331 | return -EIO; | |
1332 | } | |
1333 | ||
1334 | /* No kernel lock held - none needed ;) */ | |
37bdfb07 | 1335 | static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait) |
1da177e4 LT |
1336 | { |
1337 | return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; | |
1338 | } | |
1339 | ||
04f378b1 AC |
1340 | static long hung_up_tty_ioctl(struct file *file, unsigned int cmd, |
1341 | unsigned long arg) | |
38ad2ed0 PF |
1342 | { |
1343 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1344 | } | |
1345 | ||
37bdfb07 | 1346 | static long hung_up_tty_compat_ioctl(struct file *file, |
38ad2ed0 | 1347 | unsigned int cmd, unsigned long arg) |
1da177e4 LT |
1348 | { |
1349 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1350 | } | |
1351 | ||
62322d25 | 1352 | static const struct file_operations tty_fops = { |
1da177e4 LT |
1353 | .llseek = no_llseek, |
1354 | .read = tty_read, | |
1355 | .write = tty_write, | |
1356 | .poll = tty_poll, | |
04f378b1 | 1357 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1358 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1359 | .open = tty_open, |
1360 | .release = tty_release, | |
1361 | .fasync = tty_fasync, | |
1362 | }; | |
1363 | ||
1364 | #ifdef CONFIG_UNIX98_PTYS | |
62322d25 | 1365 | static const struct file_operations ptmx_fops = { |
1da177e4 LT |
1366 | .llseek = no_llseek, |
1367 | .read = tty_read, | |
1368 | .write = tty_write, | |
1369 | .poll = tty_poll, | |
04f378b1 | 1370 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1371 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1372 | .open = ptmx_open, |
1373 | .release = tty_release, | |
1374 | .fasync = tty_fasync, | |
1375 | }; | |
1376 | #endif | |
1377 | ||
62322d25 | 1378 | static const struct file_operations console_fops = { |
1da177e4 LT |
1379 | .llseek = no_llseek, |
1380 | .read = tty_read, | |
1381 | .write = redirected_tty_write, | |
1382 | .poll = tty_poll, | |
04f378b1 | 1383 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1384 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1385 | .open = tty_open, |
1386 | .release = tty_release, | |
1387 | .fasync = tty_fasync, | |
1388 | }; | |
1389 | ||
62322d25 | 1390 | static const struct file_operations hung_up_tty_fops = { |
1da177e4 LT |
1391 | .llseek = no_llseek, |
1392 | .read = hung_up_tty_read, | |
1393 | .write = hung_up_tty_write, | |
1394 | .poll = hung_up_tty_poll, | |
04f378b1 | 1395 | .unlocked_ioctl = hung_up_tty_ioctl, |
38ad2ed0 | 1396 | .compat_ioctl = hung_up_tty_compat_ioctl, |
1da177e4 LT |
1397 | .release = tty_release, |
1398 | }; | |
1399 | ||
1400 | static DEFINE_SPINLOCK(redirect_lock); | |
1401 | static struct file *redirect; | |
1402 | ||
1403 | /** | |
1404 | * tty_wakeup - request more data | |
1405 | * @tty: terminal | |
1406 | * | |
1407 | * Internal and external helper for wakeups of tty. This function | |
1408 | * informs the line discipline if present that the driver is ready | |
1409 | * to receive more output data. | |
1410 | */ | |
37bdfb07 | 1411 | |
1da177e4 LT |
1412 | void tty_wakeup(struct tty_struct *tty) |
1413 | { | |
1414 | struct tty_ldisc *ld; | |
37bdfb07 | 1415 | |
1da177e4 LT |
1416 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { |
1417 | ld = tty_ldisc_ref(tty); | |
37bdfb07 | 1418 | if (ld) { |
a352def2 AC |
1419 | if (ld->ops->write_wakeup) |
1420 | ld->ops->write_wakeup(tty); | |
1da177e4 LT |
1421 | tty_ldisc_deref(ld); |
1422 | } | |
1423 | } | |
1424 | wake_up_interruptible(&tty->write_wait); | |
1425 | } | |
1426 | ||
1427 | EXPORT_SYMBOL_GPL(tty_wakeup); | |
1428 | ||
1429 | /** | |
1430 | * tty_ldisc_flush - flush line discipline queue | |
1431 | * @tty: tty | |
1432 | * | |
1433 | * Flush the line discipline queue (if any) for this tty. If there | |
1434 | * is no line discipline active this is a no-op. | |
1435 | */ | |
37bdfb07 | 1436 | |
1da177e4 LT |
1437 | void tty_ldisc_flush(struct tty_struct *tty) |
1438 | { | |
1439 | struct tty_ldisc *ld = tty_ldisc_ref(tty); | |
37bdfb07 | 1440 | if (ld) { |
a352def2 AC |
1441 | if (ld->ops->flush_buffer) |
1442 | ld->ops->flush_buffer(tty); | |
1da177e4 LT |
1443 | tty_ldisc_deref(ld); |
1444 | } | |
c5c34d48 | 1445 | tty_buffer_flush(tty); |
1da177e4 LT |
1446 | } |
1447 | ||
1448 | EXPORT_SYMBOL_GPL(tty_ldisc_flush); | |
edc6afc5 AC |
1449 | |
1450 | /** | |
1451 | * tty_reset_termios - reset terminal state | |
1452 | * @tty: tty to reset | |
1453 | * | |
1454 | * Restore a terminal to the driver default state | |
1455 | */ | |
1456 | ||
1457 | static void tty_reset_termios(struct tty_struct *tty) | |
1458 | { | |
1459 | mutex_lock(&tty->termios_mutex); | |
1460 | *tty->termios = tty->driver->init_termios; | |
1461 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
1462 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1463 | mutex_unlock(&tty->termios_mutex); | |
1464 | } | |
37bdfb07 | 1465 | |
af9b897e AC |
1466 | /** |
1467 | * do_tty_hangup - actual handler for hangup events | |
65f27f38 | 1468 | * @work: tty device |
af9b897e | 1469 | * |
a352def2 | 1470 | k * This can be called by the "eventd" kernel thread. That is process |
af9b897e AC |
1471 | * synchronous but doesn't hold any locks, so we need to make sure we |
1472 | * have the appropriate locks for what we're doing. | |
1473 | * | |
1474 | * The hangup event clears any pending redirections onto the hung up | |
1475 | * device. It ensures future writes will error and it does the needed | |
1476 | * line discipline hangup and signal delivery. The tty object itself | |
1477 | * remains intact. | |
1478 | * | |
1479 | * Locking: | |
1480 | * BKL | |
24ec839c PZ |
1481 | * redirect lock for undoing redirection |
1482 | * file list lock for manipulating list of ttys | |
1483 | * tty_ldisc_lock from called functions | |
1484 | * termios_mutex resetting termios data | |
1485 | * tasklist_lock to walk task list for hangup event | |
1486 | * ->siglock to protect ->signal/->sighand | |
1da177e4 | 1487 | */ |
65f27f38 | 1488 | static void do_tty_hangup(struct work_struct *work) |
1da177e4 | 1489 | { |
65f27f38 DH |
1490 | struct tty_struct *tty = |
1491 | container_of(work, struct tty_struct, hangup_work); | |
37bdfb07 | 1492 | struct file *cons_filp = NULL; |
1da177e4 LT |
1493 | struct file *filp, *f = NULL; |
1494 | struct task_struct *p; | |
1495 | struct tty_ldisc *ld; | |
1496 | int closecount = 0, n; | |
47f86834 | 1497 | unsigned long flags; |
1da177e4 LT |
1498 | |
1499 | if (!tty) | |
1500 | return; | |
1501 | ||
1502 | /* inuse_filps is protected by the single kernel lock */ | |
1503 | lock_kernel(); | |
1504 | ||
1505 | spin_lock(&redirect_lock); | |
1506 | if (redirect && redirect->private_data == tty) { | |
1507 | f = redirect; | |
1508 | redirect = NULL; | |
1509 | } | |
1510 | spin_unlock(&redirect_lock); | |
37bdfb07 | 1511 | |
1da177e4 LT |
1512 | check_tty_count(tty, "do_tty_hangup"); |
1513 | file_list_lock(); | |
1514 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ | |
2f512016 | 1515 | list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { |
1da177e4 LT |
1516 | if (filp->f_op->write == redirected_tty_write) |
1517 | cons_filp = filp; | |
1518 | if (filp->f_op->write != tty_write) | |
1519 | continue; | |
1520 | closecount++; | |
1521 | tty_fasync(-1, filp, 0); /* can't block */ | |
1522 | filp->f_op = &hung_up_tty_fops; | |
1523 | } | |
1524 | file_list_unlock(); | |
37bdfb07 AC |
1525 | /* |
1526 | * FIXME! What are the locking issues here? This may me overdoing | |
1527 | * things... This question is especially important now that we've | |
1528 | * removed the irqlock. | |
1529 | */ | |
1da177e4 | 1530 | ld = tty_ldisc_ref(tty); |
37bdfb07 AC |
1531 | if (ld != NULL) { |
1532 | /* We may have no line discipline at this point */ | |
a352def2 AC |
1533 | if (ld->ops->flush_buffer) |
1534 | ld->ops->flush_buffer(tty); | |
f34d7a5b | 1535 | tty_driver_flush_buffer(tty); |
1da177e4 | 1536 | if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && |
a352def2 AC |
1537 | ld->ops->write_wakeup) |
1538 | ld->ops->write_wakeup(tty); | |
1539 | if (ld->ops->hangup) | |
1540 | ld->ops->hangup(tty); | |
1da177e4 | 1541 | } |
37bdfb07 AC |
1542 | /* |
1543 | * FIXME: Once we trust the LDISC code better we can wait here for | |
1544 | * ldisc completion and fix the driver call race | |
1545 | */ | |
1da177e4 LT |
1546 | wake_up_interruptible(&tty->write_wait); |
1547 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1548 | /* |
1549 | * Shutdown the current line discipline, and reset it to | |
1550 | * N_TTY. | |
1551 | */ | |
1552 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
edc6afc5 | 1553 | tty_reset_termios(tty); |
1da177e4 LT |
1554 | /* Defer ldisc switch */ |
1555 | /* tty_deferred_ldisc_switch(N_TTY); | |
37bdfb07 | 1556 | |
1da177e4 LT |
1557 | This should get done automatically when the port closes and |
1558 | tty_release is called */ | |
37bdfb07 | 1559 | |
1da177e4 | 1560 | read_lock(&tasklist_lock); |
ab521dc0 EB |
1561 | if (tty->session) { |
1562 | do_each_pid_task(tty->session, PIDTYPE_SID, p) { | |
24ec839c | 1563 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
1564 | if (p->signal->tty == tty) |
1565 | p->signal->tty = NULL; | |
24ec839c PZ |
1566 | if (!p->signal->leader) { |
1567 | spin_unlock_irq(&p->sighand->siglock); | |
1da177e4 | 1568 | continue; |
24ec839c PZ |
1569 | } |
1570 | __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); | |
1571 | __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); | |
ab521dc0 | 1572 | put_pid(p->signal->tty_old_pgrp); /* A noop */ |
47f86834 | 1573 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
ab521dc0 EB |
1574 | if (tty->pgrp) |
1575 | p->signal->tty_old_pgrp = get_pid(tty->pgrp); | |
47f86834 | 1576 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
24ec839c | 1577 | spin_unlock_irq(&p->sighand->siglock); |
ab521dc0 | 1578 | } while_each_pid_task(tty->session, PIDTYPE_SID, p); |
1da177e4 LT |
1579 | } |
1580 | read_unlock(&tasklist_lock); | |
1581 | ||
47f86834 | 1582 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 | 1583 | tty->flags = 0; |
d9c1e9a8 EB |
1584 | put_pid(tty->session); |
1585 | put_pid(tty->pgrp); | |
ab521dc0 EB |
1586 | tty->session = NULL; |
1587 | tty->pgrp = NULL; | |
1da177e4 | 1588 | tty->ctrl_status = 0; |
47f86834 AC |
1589 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1590 | ||
1da177e4 | 1591 | /* |
37bdfb07 AC |
1592 | * If one of the devices matches a console pointer, we |
1593 | * cannot just call hangup() because that will cause | |
1594 | * tty->count and state->count to go out of sync. | |
1595 | * So we just call close() the right number of times. | |
1da177e4 LT |
1596 | */ |
1597 | if (cons_filp) { | |
f34d7a5b | 1598 | if (tty->ops->close) |
1da177e4 | 1599 | for (n = 0; n < closecount; n++) |
f34d7a5b AC |
1600 | tty->ops->close(tty, cons_filp); |
1601 | } else if (tty->ops->hangup) | |
1602 | (tty->ops->hangup)(tty); | |
37bdfb07 AC |
1603 | /* |
1604 | * We don't want to have driver/ldisc interactions beyond | |
1605 | * the ones we did here. The driver layer expects no | |
1606 | * calls after ->hangup() from the ldisc side. However we | |
1607 | * can't yet guarantee all that. | |
1608 | */ | |
1da177e4 LT |
1609 | set_bit(TTY_HUPPED, &tty->flags); |
1610 | if (ld) { | |
1611 | tty_ldisc_enable(tty); | |
1612 | tty_ldisc_deref(ld); | |
1613 | } | |
1614 | unlock_kernel(); | |
1615 | if (f) | |
1616 | fput(f); | |
1617 | } | |
1618 | ||
af9b897e AC |
1619 | /** |
1620 | * tty_hangup - trigger a hangup event | |
1621 | * @tty: tty to hangup | |
1622 | * | |
1623 | * A carrier loss (virtual or otherwise) has occurred on this like | |
1624 | * schedule a hangup sequence to run after this event. | |
1625 | */ | |
1626 | ||
37bdfb07 | 1627 | void tty_hangup(struct tty_struct *tty) |
1da177e4 LT |
1628 | { |
1629 | #ifdef TTY_DEBUG_HANGUP | |
1630 | char buf[64]; | |
1da177e4 LT |
1631 | printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); |
1632 | #endif | |
1633 | schedule_work(&tty->hangup_work); | |
1634 | } | |
1635 | ||
1636 | EXPORT_SYMBOL(tty_hangup); | |
1637 | ||
af9b897e AC |
1638 | /** |
1639 | * tty_vhangup - process vhangup | |
1640 | * @tty: tty to hangup | |
1641 | * | |
1642 | * The user has asked via system call for the terminal to be hung up. | |
1643 | * We do this synchronously so that when the syscall returns the process | |
3a4fa0a2 | 1644 | * is complete. That guarantee is necessary for security reasons. |
af9b897e AC |
1645 | */ |
1646 | ||
37bdfb07 | 1647 | void tty_vhangup(struct tty_struct *tty) |
1da177e4 LT |
1648 | { |
1649 | #ifdef TTY_DEBUG_HANGUP | |
1650 | char buf[64]; | |
1651 | ||
1652 | printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); | |
1653 | #endif | |
65f27f38 | 1654 | do_tty_hangup(&tty->hangup_work); |
1da177e4 | 1655 | } |
37bdfb07 | 1656 | |
1da177e4 LT |
1657 | EXPORT_SYMBOL(tty_vhangup); |
1658 | ||
af9b897e AC |
1659 | /** |
1660 | * tty_hung_up_p - was tty hung up | |
1661 | * @filp: file pointer of tty | |
1662 | * | |
1663 | * Return true if the tty has been subject to a vhangup or a carrier | |
1664 | * loss | |
1665 | */ | |
1666 | ||
37bdfb07 | 1667 | int tty_hung_up_p(struct file *filp) |
1da177e4 LT |
1668 | { |
1669 | return (filp->f_op == &hung_up_tty_fops); | |
1670 | } | |
1671 | ||
1672 | EXPORT_SYMBOL(tty_hung_up_p); | |
1673 | ||
522ed776 | 1674 | /** |
37bdfb07 AC |
1675 | * is_tty - checker whether file is a TTY |
1676 | * @filp: file handle that may be a tty | |
1677 | * | |
1678 | * Check if the file handle is a tty handle. | |
522ed776 | 1679 | */ |
37bdfb07 | 1680 | |
522ed776 MT |
1681 | int is_tty(struct file *filp) |
1682 | { | |
1683 | return filp->f_op->read == tty_read | |
1684 | || filp->f_op->read == hung_up_tty_read; | |
1685 | } | |
1686 | ||
ab521dc0 | 1687 | static void session_clear_tty(struct pid *session) |
24ec839c PZ |
1688 | { |
1689 | struct task_struct *p; | |
ab521dc0 | 1690 | do_each_pid_task(session, PIDTYPE_SID, p) { |
24ec839c | 1691 | proc_clear_tty(p); |
ab521dc0 | 1692 | } while_each_pid_task(session, PIDTYPE_SID, p); |
24ec839c PZ |
1693 | } |
1694 | ||
af9b897e AC |
1695 | /** |
1696 | * disassociate_ctty - disconnect controlling tty | |
1697 | * @on_exit: true if exiting so need to "hang up" the session | |
1da177e4 | 1698 | * |
af9b897e AC |
1699 | * This function is typically called only by the session leader, when |
1700 | * it wants to disassociate itself from its controlling tty. | |
1701 | * | |
1702 | * It performs the following functions: | |
1da177e4 LT |
1703 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
1704 | * (2) Clears the tty from being controlling the session | |
1705 | * (3) Clears the controlling tty for all processes in the | |
1706 | * session group. | |
1707 | * | |
af9b897e AC |
1708 | * The argument on_exit is set to 1 if called when a process is |
1709 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. | |
1710 | * | |
24ec839c | 1711 | * Locking: |
af9b897e | 1712 | * BKL is taken for hysterical raisins |
24ec839c PZ |
1713 | * tty_mutex is taken to protect tty |
1714 | * ->siglock is taken to protect ->signal/->sighand | |
1715 | * tasklist_lock is taken to walk process list for sessions | |
1716 | * ->siglock is taken to protect ->signal/->sighand | |
1da177e4 | 1717 | */ |
af9b897e | 1718 | |
1da177e4 LT |
1719 | void disassociate_ctty(int on_exit) |
1720 | { | |
1721 | struct tty_struct *tty; | |
ab521dc0 | 1722 | struct pid *tty_pgrp = NULL; |
1da177e4 | 1723 | |
1da177e4 | 1724 | |
70522e12 | 1725 | mutex_lock(&tty_mutex); |
24ec839c | 1726 | tty = get_current_tty(); |
1da177e4 | 1727 | if (tty) { |
ab521dc0 | 1728 | tty_pgrp = get_pid(tty->pgrp); |
70522e12 | 1729 | mutex_unlock(&tty_mutex); |
04f378b1 | 1730 | lock_kernel(); |
24ec839c | 1731 | /* XXX: here we race, there is nothing protecting tty */ |
1da177e4 LT |
1732 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
1733 | tty_vhangup(tty); | |
04f378b1 | 1734 | unlock_kernel(); |
680a9671 | 1735 | } else if (on_exit) { |
ab521dc0 | 1736 | struct pid *old_pgrp; |
680a9671 EB |
1737 | spin_lock_irq(¤t->sighand->siglock); |
1738 | old_pgrp = current->signal->tty_old_pgrp; | |
ab521dc0 | 1739 | current->signal->tty_old_pgrp = NULL; |
680a9671 | 1740 | spin_unlock_irq(¤t->sighand->siglock); |
24ec839c | 1741 | if (old_pgrp) { |
ab521dc0 EB |
1742 | kill_pgrp(old_pgrp, SIGHUP, on_exit); |
1743 | kill_pgrp(old_pgrp, SIGCONT, on_exit); | |
1744 | put_pid(old_pgrp); | |
1da177e4 | 1745 | } |
70522e12 | 1746 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
1747 | return; |
1748 | } | |
ab521dc0 EB |
1749 | if (tty_pgrp) { |
1750 | kill_pgrp(tty_pgrp, SIGHUP, on_exit); | |
1da177e4 | 1751 | if (!on_exit) |
ab521dc0 EB |
1752 | kill_pgrp(tty_pgrp, SIGCONT, on_exit); |
1753 | put_pid(tty_pgrp); | |
1da177e4 LT |
1754 | } |
1755 | ||
24ec839c | 1756 | spin_lock_irq(¤t->sighand->siglock); |
2a65f1d9 | 1757 | put_pid(current->signal->tty_old_pgrp); |
23cac8de | 1758 | current->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
1759 | spin_unlock_irq(¤t->sighand->siglock); |
1760 | ||
1761 | mutex_lock(&tty_mutex); | |
1762 | /* It is possible that do_tty_hangup has free'd this tty */ | |
1763 | tty = get_current_tty(); | |
1764 | if (tty) { | |
47f86834 AC |
1765 | unsigned long flags; |
1766 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
ab521dc0 EB |
1767 | put_pid(tty->session); |
1768 | put_pid(tty->pgrp); | |
1769 | tty->session = NULL; | |
1770 | tty->pgrp = NULL; | |
47f86834 | 1771 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
24ec839c PZ |
1772 | } else { |
1773 | #ifdef TTY_DEBUG_HANGUP | |
1774 | printk(KERN_DEBUG "error attempted to write to tty [0x%p]" | |
1775 | " = NULL", tty); | |
1776 | #endif | |
1777 | } | |
1778 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
1779 | |
1780 | /* Now clear signal->tty under the lock */ | |
1781 | read_lock(&tasklist_lock); | |
ab521dc0 | 1782 | session_clear_tty(task_session(current)); |
1da177e4 | 1783 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1784 | } |
1785 | ||
98a27ba4 EB |
1786 | /** |
1787 | * | |
1788 | * no_tty - Ensure the current process does not have a controlling tty | |
1789 | */ | |
1790 | void no_tty(void) | |
1791 | { | |
1792 | struct task_struct *tsk = current; | |
04f378b1 | 1793 | lock_kernel(); |
98a27ba4 EB |
1794 | if (tsk->signal->leader) |
1795 | disassociate_ctty(0); | |
04f378b1 | 1796 | unlock_kernel(); |
98a27ba4 EB |
1797 | proc_clear_tty(tsk); |
1798 | } | |
1799 | ||
af9b897e AC |
1800 | |
1801 | /** | |
beb7dd86 | 1802 | * stop_tty - propagate flow control |
af9b897e AC |
1803 | * @tty: tty to stop |
1804 | * | |
1805 | * Perform flow control to the driver. For PTY/TTY pairs we | |
beb7dd86 | 1806 | * must also propagate the TIOCKPKT status. May be called |
af9b897e AC |
1807 | * on an already stopped device and will not re-call the driver |
1808 | * method. | |
1809 | * | |
1810 | * This functionality is used by both the line disciplines for | |
1811 | * halting incoming flow and by the driver. It may therefore be | |
1812 | * called from any context, may be under the tty atomic_write_lock | |
1813 | * but not always. | |
1814 | * | |
1815 | * Locking: | |
04f378b1 | 1816 | * Uses the tty control lock internally |
af9b897e AC |
1817 | */ |
1818 | ||
1da177e4 LT |
1819 | void stop_tty(struct tty_struct *tty) |
1820 | { | |
04f378b1 AC |
1821 | unsigned long flags; |
1822 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
1823 | if (tty->stopped) { | |
1824 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
1da177e4 | 1825 | return; |
04f378b1 | 1826 | } |
1da177e4 LT |
1827 | tty->stopped = 1; |
1828 | if (tty->link && tty->link->packet) { | |
1829 | tty->ctrl_status &= ~TIOCPKT_START; | |
1830 | tty->ctrl_status |= TIOCPKT_STOP; | |
1831 | wake_up_interruptible(&tty->link->read_wait); | |
1832 | } | |
04f378b1 | 1833 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
f34d7a5b AC |
1834 | if (tty->ops->stop) |
1835 | (tty->ops->stop)(tty); | |
1da177e4 LT |
1836 | } |
1837 | ||
1838 | EXPORT_SYMBOL(stop_tty); | |
1839 | ||
af9b897e | 1840 | /** |
beb7dd86 | 1841 | * start_tty - propagate flow control |
af9b897e AC |
1842 | * @tty: tty to start |
1843 | * | |
1844 | * Start a tty that has been stopped if at all possible. Perform | |
3a4fa0a2 | 1845 | * any necessary wakeups and propagate the TIOCPKT status. If this |
af9b897e AC |
1846 | * is the tty was previous stopped and is being started then the |
1847 | * driver start method is invoked and the line discipline woken. | |
1848 | * | |
1849 | * Locking: | |
04f378b1 | 1850 | * ctrl_lock |
af9b897e AC |
1851 | */ |
1852 | ||
1da177e4 LT |
1853 | void start_tty(struct tty_struct *tty) |
1854 | { | |
04f378b1 AC |
1855 | unsigned long flags; |
1856 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
1857 | if (!tty->stopped || tty->flow_stopped) { | |
1858 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
1da177e4 | 1859 | return; |
04f378b1 | 1860 | } |
1da177e4 LT |
1861 | tty->stopped = 0; |
1862 | if (tty->link && tty->link->packet) { | |
1863 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
1864 | tty->ctrl_status |= TIOCPKT_START; | |
1865 | wake_up_interruptible(&tty->link->read_wait); | |
1866 | } | |
04f378b1 | 1867 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
f34d7a5b AC |
1868 | if (tty->ops->start) |
1869 | (tty->ops->start)(tty); | |
1da177e4 LT |
1870 | /* If we have a running line discipline it may need kicking */ |
1871 | tty_wakeup(tty); | |
1da177e4 LT |
1872 | } |
1873 | ||
1874 | EXPORT_SYMBOL(start_tty); | |
1875 | ||
af9b897e AC |
1876 | /** |
1877 | * tty_read - read method for tty device files | |
1878 | * @file: pointer to tty file | |
1879 | * @buf: user buffer | |
1880 | * @count: size of user buffer | |
1881 | * @ppos: unused | |
1882 | * | |
1883 | * Perform the read system call function on this terminal device. Checks | |
1884 | * for hung up devices before calling the line discipline method. | |
1885 | * | |
1886 | * Locking: | |
47f86834 AC |
1887 | * Locks the line discipline internally while needed. Multiple |
1888 | * read calls may be outstanding in parallel. | |
af9b897e AC |
1889 | */ |
1890 | ||
37bdfb07 | 1891 | static ssize_t tty_read(struct file *file, char __user *buf, size_t count, |
1da177e4 LT |
1892 | loff_t *ppos) |
1893 | { | |
1894 | int i; | |
37bdfb07 | 1895 | struct tty_struct *tty; |
1da177e4 LT |
1896 | struct inode *inode; |
1897 | struct tty_ldisc *ld; | |
1898 | ||
1899 | tty = (struct tty_struct *)file->private_data; | |
a7113a96 | 1900 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1901 | if (tty_paranoia_check(tty, inode, "tty_read")) |
1902 | return -EIO; | |
1903 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1904 | return -EIO; | |
1905 | ||
1906 | /* We want to wait for the line discipline to sort out in this | |
1907 | situation */ | |
1908 | ld = tty_ldisc_ref_wait(tty); | |
a352def2 AC |
1909 | if (ld->ops->read) |
1910 | i = (ld->ops->read)(tty, file, buf, count); | |
1da177e4 LT |
1911 | else |
1912 | i = -EIO; | |
1913 | tty_ldisc_deref(ld); | |
1da177e4 LT |
1914 | if (i > 0) |
1915 | inode->i_atime = current_fs_time(inode->i_sb); | |
1916 | return i; | |
1917 | } | |
1918 | ||
9c1729db AC |
1919 | void tty_write_unlock(struct tty_struct *tty) |
1920 | { | |
1921 | mutex_unlock(&tty->atomic_write_lock); | |
1922 | wake_up_interruptible(&tty->write_wait); | |
1923 | } | |
1924 | ||
1925 | int tty_write_lock(struct tty_struct *tty, int ndelay) | |
1926 | { | |
1927 | if (!mutex_trylock(&tty->atomic_write_lock)) { | |
1928 | if (ndelay) | |
1929 | return -EAGAIN; | |
1930 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) | |
1931 | return -ERESTARTSYS; | |
1932 | } | |
1933 | return 0; | |
1934 | } | |
1935 | ||
1da177e4 LT |
1936 | /* |
1937 | * Split writes up in sane blocksizes to avoid | |
1938 | * denial-of-service type attacks | |
1939 | */ | |
1940 | static inline ssize_t do_tty_write( | |
1941 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
1942 | struct tty_struct *tty, | |
1943 | struct file *file, | |
1944 | const char __user *buf, | |
1945 | size_t count) | |
1946 | { | |
9c1729db | 1947 | ssize_t ret, written = 0; |
1da177e4 | 1948 | unsigned int chunk; |
37bdfb07 | 1949 | |
9c1729db AC |
1950 | ret = tty_write_lock(tty, file->f_flags & O_NDELAY); |
1951 | if (ret < 0) | |
1952 | return ret; | |
1da177e4 LT |
1953 | |
1954 | /* | |
1955 | * We chunk up writes into a temporary buffer. This | |
1956 | * simplifies low-level drivers immensely, since they | |
1957 | * don't have locking issues and user mode accesses. | |
1958 | * | |
1959 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
1960 | * big chunk-size.. | |
1961 | * | |
1962 | * The default chunk-size is 2kB, because the NTTY | |
1963 | * layer has problems with bigger chunks. It will | |
1964 | * claim to be able to handle more characters than | |
1965 | * it actually does. | |
af9b897e AC |
1966 | * |
1967 | * FIXME: This can probably go away now except that 64K chunks | |
1968 | * are too likely to fail unless switched to vmalloc... | |
1da177e4 LT |
1969 | */ |
1970 | chunk = 2048; | |
1971 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
1972 | chunk = 65536; | |
1973 | if (count < chunk) | |
1974 | chunk = count; | |
1975 | ||
70522e12 | 1976 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
1da177e4 LT |
1977 | if (tty->write_cnt < chunk) { |
1978 | unsigned char *buf; | |
1979 | ||
1980 | if (chunk < 1024) | |
1981 | chunk = 1024; | |
1982 | ||
1983 | buf = kmalloc(chunk, GFP_KERNEL); | |
1984 | if (!buf) { | |
9c1729db AC |
1985 | ret = -ENOMEM; |
1986 | goto out; | |
1da177e4 LT |
1987 | } |
1988 | kfree(tty->write_buf); | |
1989 | tty->write_cnt = chunk; | |
1990 | tty->write_buf = buf; | |
1991 | } | |
1992 | ||
1993 | /* Do the write .. */ | |
1994 | for (;;) { | |
1995 | size_t size = count; | |
1996 | if (size > chunk) | |
1997 | size = chunk; | |
1998 | ret = -EFAULT; | |
1999 | if (copy_from_user(tty->write_buf, buf, size)) | |
2000 | break; | |
1da177e4 | 2001 | ret = write(tty, file, tty->write_buf, size); |
1da177e4 LT |
2002 | if (ret <= 0) |
2003 | break; | |
2004 | written += ret; | |
2005 | buf += ret; | |
2006 | count -= ret; | |
2007 | if (!count) | |
2008 | break; | |
2009 | ret = -ERESTARTSYS; | |
2010 | if (signal_pending(current)) | |
2011 | break; | |
2012 | cond_resched(); | |
2013 | } | |
2014 | if (written) { | |
a7113a96 | 2015 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
2016 | inode->i_mtime = current_fs_time(inode->i_sb); |
2017 | ret = written; | |
2018 | } | |
9c1729db AC |
2019 | out: |
2020 | tty_write_unlock(tty); | |
1da177e4 LT |
2021 | return ret; |
2022 | } | |
2023 | ||
2024 | ||
af9b897e AC |
2025 | /** |
2026 | * tty_write - write method for tty device file | |
2027 | * @file: tty file pointer | |
2028 | * @buf: user data to write | |
2029 | * @count: bytes to write | |
2030 | * @ppos: unused | |
2031 | * | |
2032 | * Write data to a tty device via the line discipline. | |
2033 | * | |
2034 | * Locking: | |
2035 | * Locks the line discipline as required | |
2036 | * Writes to the tty driver are serialized by the atomic_write_lock | |
2037 | * and are then processed in chunks to the device. The line discipline | |
2038 | * write method will not be involked in parallel for each device | |
2039 | * The line discipline write method is called under the big | |
2040 | * kernel lock for historical reasons. New code should not rely on this. | |
2041 | */ | |
2042 | ||
37bdfb07 AC |
2043 | static ssize_t tty_write(struct file *file, const char __user *buf, |
2044 | size_t count, loff_t *ppos) | |
1da177e4 | 2045 | { |
37bdfb07 | 2046 | struct tty_struct *tty; |
a7113a96 | 2047 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
2048 | ssize_t ret; |
2049 | struct tty_ldisc *ld; | |
37bdfb07 | 2050 | |
1da177e4 LT |
2051 | tty = (struct tty_struct *)file->private_data; |
2052 | if (tty_paranoia_check(tty, inode, "tty_write")) | |
2053 | return -EIO; | |
f34d7a5b | 2054 | if (!tty || !tty->ops->write || |
37bdfb07 AC |
2055 | (test_bit(TTY_IO_ERROR, &tty->flags))) |
2056 | return -EIO; | |
f34d7a5b AC |
2057 | /* Short term debug to catch buggy drivers */ |
2058 | if (tty->ops->write_room == NULL) | |
2059 | printk(KERN_ERR "tty driver %s lacks a write_room method.\n", | |
2060 | tty->driver->name); | |
37bdfb07 | 2061 | ld = tty_ldisc_ref_wait(tty); |
a352def2 | 2062 | if (!ld->ops->write) |
1da177e4 LT |
2063 | ret = -EIO; |
2064 | else | |
a352def2 | 2065 | ret = do_tty_write(ld->ops->write, tty, file, buf, count); |
1da177e4 LT |
2066 | tty_ldisc_deref(ld); |
2067 | return ret; | |
2068 | } | |
2069 | ||
37bdfb07 AC |
2070 | ssize_t redirected_tty_write(struct file *file, const char __user *buf, |
2071 | size_t count, loff_t *ppos) | |
1da177e4 LT |
2072 | { |
2073 | struct file *p = NULL; | |
2074 | ||
2075 | spin_lock(&redirect_lock); | |
2076 | if (redirect) { | |
2077 | get_file(redirect); | |
2078 | p = redirect; | |
2079 | } | |
2080 | spin_unlock(&redirect_lock); | |
2081 | ||
2082 | if (p) { | |
2083 | ssize_t res; | |
2084 | res = vfs_write(p, buf, count, &p->f_pos); | |
2085 | fput(p); | |
2086 | return res; | |
2087 | } | |
1da177e4 LT |
2088 | return tty_write(file, buf, count, ppos); |
2089 | } | |
2090 | ||
2091 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
2092 | ||
af9b897e AC |
2093 | /** |
2094 | * pty_line_name - generate name for a pty | |
2095 | * @driver: the tty driver in use | |
2096 | * @index: the minor number | |
2097 | * @p: output buffer of at least 6 bytes | |
2098 | * | |
2099 | * Generate a name from a driver reference and write it to the output | |
2100 | * buffer. | |
2101 | * | |
2102 | * Locking: None | |
2103 | */ | |
2104 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
2105 | { |
2106 | int i = index + driver->name_base; | |
2107 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
2108 | sprintf(p, "%s%c%x", | |
37bdfb07 AC |
2109 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, |
2110 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1da177e4 LT |
2111 | } |
2112 | ||
af9b897e AC |
2113 | /** |
2114 | * pty_line_name - generate name for a tty | |
2115 | * @driver: the tty driver in use | |
2116 | * @index: the minor number | |
2117 | * @p: output buffer of at least 7 bytes | |
2118 | * | |
2119 | * Generate a name from a driver reference and write it to the output | |
2120 | * buffer. | |
2121 | * | |
2122 | * Locking: None | |
2123 | */ | |
2124 | static void tty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
2125 | { |
2126 | sprintf(p, "%s%d", driver->name, index + driver->name_base); | |
2127 | } | |
2128 | ||
af9b897e AC |
2129 | /** |
2130 | * init_dev - initialise a tty device | |
2131 | * @driver: tty driver we are opening a device on | |
2132 | * @idx: device index | |
2133 | * @tty: returned tty structure | |
2134 | * | |
2135 | * Prepare a tty device. This may not be a "new" clean device but | |
2136 | * could also be an active device. The pty drivers require special | |
2137 | * handling because of this. | |
2138 | * | |
2139 | * Locking: | |
2140 | * The function is called under the tty_mutex, which | |
2141 | * protects us from the tty struct or driver itself going away. | |
2142 | * | |
2143 | * On exit the tty device has the line discipline attached and | |
2144 | * a reference count of 1. If a pair was created for pty/tty use | |
2145 | * and the other was a pty master then it too has a reference count of 1. | |
2146 | * | |
1da177e4 | 2147 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
70522e12 IM |
2148 | * failed open. The new code protects the open with a mutex, so it's |
2149 | * really quite straightforward. The mutex locking can probably be | |
1da177e4 LT |
2150 | * relaxed for the (most common) case of reopening a tty. |
2151 | */ | |
af9b897e | 2152 | |
1da177e4 LT |
2153 | static int init_dev(struct tty_driver *driver, int idx, |
2154 | struct tty_struct **ret_tty) | |
2155 | { | |
2156 | struct tty_struct *tty, *o_tty; | |
edc6afc5 AC |
2157 | struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; |
2158 | struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; | |
af9b897e | 2159 | int retval = 0; |
a352def2 | 2160 | struct tty_ldisc *ld; |
1da177e4 LT |
2161 | |
2162 | /* check whether we're reopening an existing tty */ | |
2163 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2164 | tty = devpts_get_tty(idx); | |
5a39e8c6 ASRF |
2165 | /* |
2166 | * If we don't have a tty here on a slave open, it's because | |
2167 | * the master already started the close process and there's | |
2168 | * no relation between devpts file and tty anymore. | |
2169 | */ | |
2170 | if (!tty && driver->subtype == PTY_TYPE_SLAVE) { | |
2171 | retval = -EIO; | |
2172 | goto end_init; | |
2173 | } | |
2174 | /* | |
2175 | * It's safe from now on because init_dev() is called with | |
2176 | * tty_mutex held and release_dev() won't change tty->count | |
2177 | * or tty->flags without having to grab tty_mutex | |
2178 | */ | |
1da177e4 LT |
2179 | if (tty && driver->subtype == PTY_TYPE_MASTER) |
2180 | tty = tty->link; | |
2181 | } else { | |
2182 | tty = driver->ttys[idx]; | |
2183 | } | |
2184 | if (tty) goto fast_track; | |
2185 | ||
2186 | /* | |
2187 | * First time open is complex, especially for PTY devices. | |
2188 | * This code guarantees that either everything succeeds and the | |
2189 | * TTY is ready for operation, or else the table slots are vacated | |
37bdfb07 | 2190 | * and the allocated memory released. (Except that the termios |
1da177e4 LT |
2191 | * and locked termios may be retained.) |
2192 | */ | |
2193 | ||
2194 | if (!try_module_get(driver->owner)) { | |
2195 | retval = -ENODEV; | |
2196 | goto end_init; | |
2197 | } | |
2198 | ||
2199 | o_tty = NULL; | |
2200 | tp = o_tp = NULL; | |
2201 | ltp = o_ltp = NULL; | |
2202 | ||
2203 | tty = alloc_tty_struct(); | |
37bdfb07 | 2204 | if (!tty) |
1da177e4 LT |
2205 | goto fail_no_mem; |
2206 | initialize_tty_struct(tty); | |
2207 | tty->driver = driver; | |
f34d7a5b | 2208 | tty->ops = driver->ops; |
1da177e4 LT |
2209 | tty->index = idx; |
2210 | tty_line_name(driver, idx, tty->name); | |
2211 | ||
2212 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2213 | tp_loc = &tty->termios; | |
2214 | ltp_loc = &tty->termios_locked; | |
2215 | } else { | |
2216 | tp_loc = &driver->termios[idx]; | |
2217 | ltp_loc = &driver->termios_locked[idx]; | |
2218 | } | |
2219 | ||
2220 | if (!*tp_loc) { | |
abcb1ff3 | 2221 | tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2222 | if (!tp) |
2223 | goto free_mem_out; | |
2224 | *tp = driver->init_termios; | |
2225 | } | |
2226 | ||
2227 | if (!*ltp_loc) { | |
506eb99a | 2228 | ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2229 | if (!ltp) |
2230 | goto free_mem_out; | |
1da177e4 LT |
2231 | } |
2232 | ||
2233 | if (driver->type == TTY_DRIVER_TYPE_PTY) { | |
2234 | o_tty = alloc_tty_struct(); | |
2235 | if (!o_tty) | |
2236 | goto free_mem_out; | |
2237 | initialize_tty_struct(o_tty); | |
2238 | o_tty->driver = driver->other; | |
f34d7a5b | 2239 | o_tty->ops = driver->ops; |
1da177e4 LT |
2240 | o_tty->index = idx; |
2241 | tty_line_name(driver->other, idx, o_tty->name); | |
2242 | ||
2243 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2244 | o_tp_loc = &o_tty->termios; | |
2245 | o_ltp_loc = &o_tty->termios_locked; | |
2246 | } else { | |
2247 | o_tp_loc = &driver->other->termios[idx]; | |
2248 | o_ltp_loc = &driver->other->termios_locked[idx]; | |
2249 | } | |
2250 | ||
2251 | if (!*o_tp_loc) { | |
abcb1ff3 | 2252 | o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2253 | if (!o_tp) |
2254 | goto free_mem_out; | |
2255 | *o_tp = driver->other->init_termios; | |
2256 | } | |
2257 | ||
2258 | if (!*o_ltp_loc) { | |
506eb99a | 2259 | o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2260 | if (!o_ltp) |
2261 | goto free_mem_out; | |
1da177e4 LT |
2262 | } |
2263 | ||
2264 | /* | |
2265 | * Everything allocated ... set up the o_tty structure. | |
2266 | */ | |
37bdfb07 | 2267 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) |
1da177e4 | 2268 | driver->other->ttys[idx] = o_tty; |
1da177e4 LT |
2269 | if (!*o_tp_loc) |
2270 | *o_tp_loc = o_tp; | |
2271 | if (!*o_ltp_loc) | |
2272 | *o_ltp_loc = o_ltp; | |
2273 | o_tty->termios = *o_tp_loc; | |
2274 | o_tty->termios_locked = *o_ltp_loc; | |
2275 | driver->other->refcount++; | |
2276 | if (driver->subtype == PTY_TYPE_MASTER) | |
2277 | o_tty->count++; | |
2278 | ||
2279 | /* Establish the links in both directions */ | |
2280 | tty->link = o_tty; | |
2281 | o_tty->link = tty; | |
2282 | } | |
2283 | ||
37bdfb07 | 2284 | /* |
1da177e4 | 2285 | * All structures have been allocated, so now we install them. |
d5698c28 | 2286 | * Failures after this point use release_tty to clean up, so |
1da177e4 LT |
2287 | * there's no need to null out the local pointers. |
2288 | */ | |
37bdfb07 | 2289 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) |
1da177e4 | 2290 | driver->ttys[idx] = tty; |
37bdfb07 | 2291 | |
1da177e4 LT |
2292 | if (!*tp_loc) |
2293 | *tp_loc = tp; | |
2294 | if (!*ltp_loc) | |
2295 | *ltp_loc = ltp; | |
2296 | tty->termios = *tp_loc; | |
2297 | tty->termios_locked = *ltp_loc; | |
edc6afc5 AC |
2298 | /* Compatibility until drivers always set this */ |
2299 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
2300 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1da177e4 LT |
2301 | driver->refcount++; |
2302 | tty->count++; | |
2303 | ||
37bdfb07 | 2304 | /* |
1da177e4 | 2305 | * Structures all installed ... call the ldisc open routines. |
d5698c28 CH |
2306 | * If we fail here just call release_tty to clean up. No need |
2307 | * to decrement the use counts, as release_tty doesn't care. | |
1da177e4 | 2308 | */ |
a352def2 AC |
2309 | |
2310 | ld = &tty->ldisc; | |
1da177e4 | 2311 | |
a352def2 AC |
2312 | if (ld->ops->open) { |
2313 | retval = (ld->ops->open)(tty); | |
1da177e4 LT |
2314 | if (retval) |
2315 | goto release_mem_out; | |
2316 | } | |
a352def2 AC |
2317 | if (o_tty && o_tty->ldisc.ops->open) { |
2318 | retval = (o_tty->ldisc.ops->open)(o_tty); | |
1da177e4 | 2319 | if (retval) { |
a352def2 AC |
2320 | if (ld->ops->close) |
2321 | (ld->ops->close)(tty); | |
1da177e4 LT |
2322 | goto release_mem_out; |
2323 | } | |
2324 | tty_ldisc_enable(o_tty); | |
2325 | } | |
2326 | tty_ldisc_enable(tty); | |
2327 | goto success; | |
2328 | ||
2329 | /* | |
2330 | * This fast open can be used if the tty is already open. | |
2331 | * No memory is allocated, and the only failures are from | |
2332 | * attempting to open a closing tty or attempting multiple | |
2333 | * opens on a pty master. | |
2334 | */ | |
2335 | fast_track: | |
2336 | if (test_bit(TTY_CLOSING, &tty->flags)) { | |
2337 | retval = -EIO; | |
2338 | goto end_init; | |
2339 | } | |
2340 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
2341 | driver->subtype == PTY_TYPE_MASTER) { | |
2342 | /* | |
37bdfb07 | 2343 | * special case for PTY masters: only one open permitted, |
1da177e4 LT |
2344 | * and the slave side open count is incremented as well. |
2345 | */ | |
2346 | if (tty->count) { | |
2347 | retval = -EIO; | |
2348 | goto end_init; | |
2349 | } | |
2350 | tty->link->count++; | |
2351 | } | |
2352 | tty->count++; | |
2353 | tty->driver = driver; /* N.B. why do this every time?? */ | |
2354 | ||
2355 | /* FIXME */ | |
37bdfb07 | 2356 | if (!test_bit(TTY_LDISC, &tty->flags)) |
1da177e4 LT |
2357 | printk(KERN_ERR "init_dev but no ldisc\n"); |
2358 | success: | |
2359 | *ret_tty = tty; | |
37bdfb07 | 2360 | |
70522e12 | 2361 | /* All paths come through here to release the mutex */ |
1da177e4 LT |
2362 | end_init: |
2363 | return retval; | |
2364 | ||
2365 | /* Release locally allocated memory ... nothing placed in slots */ | |
2366 | free_mem_out: | |
735d5661 | 2367 | kfree(o_tp); |
1da177e4 LT |
2368 | if (o_tty) |
2369 | free_tty_struct(o_tty); | |
735d5661 JJ |
2370 | kfree(ltp); |
2371 | kfree(tp); | |
1da177e4 LT |
2372 | free_tty_struct(tty); |
2373 | ||
2374 | fail_no_mem: | |
2375 | module_put(driver->owner); | |
2376 | retval = -ENOMEM; | |
2377 | goto end_init; | |
2378 | ||
d5698c28 | 2379 | /* call the tty release_tty routine to clean out this slot */ |
1da177e4 | 2380 | release_mem_out: |
4050914f AM |
2381 | if (printk_ratelimit()) |
2382 | printk(KERN_INFO "init_dev: ldisc open failed, " | |
2383 | "clearing slot %d\n", idx); | |
d5698c28 | 2384 | release_tty(tty, idx); |
1da177e4 LT |
2385 | goto end_init; |
2386 | } | |
2387 | ||
af9b897e | 2388 | /** |
d5698c28 | 2389 | * release_one_tty - release tty structure memory |
af9b897e AC |
2390 | * |
2391 | * Releases memory associated with a tty structure, and clears out the | |
2392 | * driver table slots. This function is called when a device is no longer | |
2393 | * in use. It also gets called when setup of a device fails. | |
2394 | * | |
2395 | * Locking: | |
2396 | * tty_mutex - sometimes only | |
2397 | * takes the file list lock internally when working on the list | |
2398 | * of ttys that the driver keeps. | |
2399 | * FIXME: should we require tty_mutex is held here ?? | |
1da177e4 | 2400 | */ |
d5698c28 | 2401 | static void release_one_tty(struct tty_struct *tty, int idx) |
1da177e4 | 2402 | { |
1da177e4 | 2403 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
d5698c28 | 2404 | struct ktermios *tp; |
1da177e4 LT |
2405 | |
2406 | if (!devpts) | |
2407 | tty->driver->ttys[idx] = NULL; | |
d5698c28 | 2408 | |
1da177e4 LT |
2409 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
2410 | tp = tty->termios; | |
2411 | if (!devpts) | |
2412 | tty->driver->termios[idx] = NULL; | |
2413 | kfree(tp); | |
2414 | ||
2415 | tp = tty->termios_locked; | |
2416 | if (!devpts) | |
2417 | tty->driver->termios_locked[idx] = NULL; | |
2418 | kfree(tp); | |
2419 | } | |
2420 | ||
d5698c28 | 2421 | |
1da177e4 LT |
2422 | tty->magic = 0; |
2423 | tty->driver->refcount--; | |
d5698c28 | 2424 | |
1da177e4 LT |
2425 | file_list_lock(); |
2426 | list_del_init(&tty->tty_files); | |
2427 | file_list_unlock(); | |
d5698c28 | 2428 | |
1da177e4 LT |
2429 | free_tty_struct(tty); |
2430 | } | |
2431 | ||
d5698c28 CH |
2432 | /** |
2433 | * release_tty - release tty structure memory | |
2434 | * | |
2435 | * Release both @tty and a possible linked partner (think pty pair), | |
2436 | * and decrement the refcount of the backing module. | |
2437 | * | |
2438 | * Locking: | |
2439 | * tty_mutex - sometimes only | |
2440 | * takes the file list lock internally when working on the list | |
2441 | * of ttys that the driver keeps. | |
2442 | * FIXME: should we require tty_mutex is held here ?? | |
2443 | */ | |
2444 | static void release_tty(struct tty_struct *tty, int idx) | |
2445 | { | |
2446 | struct tty_driver *driver = tty->driver; | |
2447 | ||
2448 | if (tty->link) | |
2449 | release_one_tty(tty->link, idx); | |
2450 | release_one_tty(tty, idx); | |
2451 | module_put(driver->owner); | |
2452 | } | |
2453 | ||
1da177e4 LT |
2454 | /* |
2455 | * Even releasing the tty structures is a tricky business.. We have | |
2456 | * to be very careful that the structures are all released at the | |
2457 | * same time, as interrupts might otherwise get the wrong pointers. | |
2458 | * | |
2459 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
2460 | * lead to double frees or releasing memory still in use. | |
2461 | */ | |
37bdfb07 | 2462 | static void release_dev(struct file *filp) |
1da177e4 LT |
2463 | { |
2464 | struct tty_struct *tty, *o_tty; | |
a352def2 | 2465 | struct tty_ldisc ld; |
1da177e4 | 2466 | int pty_master, tty_closing, o_tty_closing, do_sleep; |
14a6283e | 2467 | int devpts; |
1da177e4 LT |
2468 | int idx; |
2469 | char buf[64]; | |
2470 | unsigned long flags; | |
37bdfb07 | 2471 | |
1da177e4 | 2472 | tty = (struct tty_struct *)filp->private_data; |
37bdfb07 AC |
2473 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, |
2474 | "release_dev")) | |
1da177e4 LT |
2475 | return; |
2476 | ||
2477 | check_tty_count(tty, "release_dev"); | |
2478 | ||
2479 | tty_fasync(-1, filp, 0); | |
2480 | ||
2481 | idx = tty->index; | |
2482 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2483 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2484 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; | |
1da177e4 LT |
2485 | o_tty = tty->link; |
2486 | ||
2487 | #ifdef TTY_PARANOIA_CHECK | |
2488 | if (idx < 0 || idx >= tty->driver->num) { | |
2489 | printk(KERN_DEBUG "release_dev: bad idx when trying to " | |
2490 | "free (%s)\n", tty->name); | |
2491 | return; | |
2492 | } | |
2493 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2494 | if (tty != tty->driver->ttys[idx]) { | |
2495 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " | |
2496 | "for (%s)\n", idx, tty->name); | |
2497 | return; | |
2498 | } | |
2499 | if (tty->termios != tty->driver->termios[idx]) { | |
2500 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " | |
2501 | "for (%s)\n", | |
2502 | idx, tty->name); | |
2503 | return; | |
2504 | } | |
2505 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { | |
2506 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " | |
2507 | "termios_locked for (%s)\n", | |
2508 | idx, tty->name); | |
2509 | return; | |
2510 | } | |
2511 | } | |
2512 | #endif | |
2513 | ||
2514 | #ifdef TTY_DEBUG_HANGUP | |
2515 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", | |
2516 | tty_name(tty, buf), tty->count); | |
2517 | #endif | |
2518 | ||
2519 | #ifdef TTY_PARANOIA_CHECK | |
2520 | if (tty->driver->other && | |
2521 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2522 | if (o_tty != tty->driver->other->ttys[idx]) { | |
2523 | printk(KERN_DEBUG "release_dev: other->table[%d] " | |
2524 | "not o_tty for (%s)\n", | |
2525 | idx, tty->name); | |
2526 | return; | |
2527 | } | |
2528 | if (o_tty->termios != tty->driver->other->termios[idx]) { | |
2529 | printk(KERN_DEBUG "release_dev: other->termios[%d] " | |
2530 | "not o_termios for (%s)\n", | |
2531 | idx, tty->name); | |
2532 | return; | |
2533 | } | |
37bdfb07 | 2534 | if (o_tty->termios_locked != |
1da177e4 LT |
2535 | tty->driver->other->termios_locked[idx]) { |
2536 | printk(KERN_DEBUG "release_dev: other->termios_locked[" | |
2537 | "%d] not o_termios_locked for (%s)\n", | |
2538 | idx, tty->name); | |
2539 | return; | |
2540 | } | |
2541 | if (o_tty->link != tty) { | |
2542 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); | |
2543 | return; | |
2544 | } | |
2545 | } | |
2546 | #endif | |
f34d7a5b AC |
2547 | if (tty->ops->close) |
2548 | tty->ops->close(tty, filp); | |
1da177e4 LT |
2549 | |
2550 | /* | |
2551 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
2552 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
2553 | * wait queues and kick everyone out _before_ actually starting to | |
2554 | * close. This ensures that we won't block while releasing the tty | |
2555 | * structure. | |
2556 | * | |
2557 | * The test for the o_tty closing is necessary, since the master and | |
2558 | * slave sides may close in any order. If the slave side closes out | |
2559 | * first, its count will be one, since the master side holds an open. | |
2560 | * Thus this test wouldn't be triggered at the time the slave closes, | |
2561 | * so we do it now. | |
2562 | * | |
2563 | * Note that it's possible for the tty to be opened again while we're | |
2564 | * flushing out waiters. By recalculating the closing flags before | |
2565 | * each iteration we avoid any problems. | |
2566 | */ | |
2567 | while (1) { | |
2568 | /* Guard against races with tty->count changes elsewhere and | |
2569 | opens on /dev/tty */ | |
37bdfb07 | 2570 | |
70522e12 | 2571 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2572 | tty_closing = tty->count <= 1; |
2573 | o_tty_closing = o_tty && | |
2574 | (o_tty->count <= (pty_master ? 1 : 0)); | |
1da177e4 LT |
2575 | do_sleep = 0; |
2576 | ||
2577 | if (tty_closing) { | |
2578 | if (waitqueue_active(&tty->read_wait)) { | |
2579 | wake_up(&tty->read_wait); | |
2580 | do_sleep++; | |
2581 | } | |
2582 | if (waitqueue_active(&tty->write_wait)) { | |
2583 | wake_up(&tty->write_wait); | |
2584 | do_sleep++; | |
2585 | } | |
2586 | } | |
2587 | if (o_tty_closing) { | |
2588 | if (waitqueue_active(&o_tty->read_wait)) { | |
2589 | wake_up(&o_tty->read_wait); | |
2590 | do_sleep++; | |
2591 | } | |
2592 | if (waitqueue_active(&o_tty->write_wait)) { | |
2593 | wake_up(&o_tty->write_wait); | |
2594 | do_sleep++; | |
2595 | } | |
2596 | } | |
2597 | if (!do_sleep) | |
2598 | break; | |
2599 | ||
2600 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " | |
2601 | "active!\n", tty_name(tty, buf)); | |
70522e12 | 2602 | mutex_unlock(&tty_mutex); |
1da177e4 | 2603 | schedule(); |
37bdfb07 | 2604 | } |
1da177e4 LT |
2605 | |
2606 | /* | |
37bdfb07 AC |
2607 | * The closing flags are now consistent with the open counts on |
2608 | * both sides, and we've completed the last operation that could | |
1da177e4 LT |
2609 | * block, so it's safe to proceed with closing. |
2610 | */ | |
1da177e4 LT |
2611 | if (pty_master) { |
2612 | if (--o_tty->count < 0) { | |
2613 | printk(KERN_WARNING "release_dev: bad pty slave count " | |
2614 | "(%d) for %s\n", | |
2615 | o_tty->count, tty_name(o_tty, buf)); | |
2616 | o_tty->count = 0; | |
2617 | } | |
2618 | } | |
2619 | if (--tty->count < 0) { | |
2620 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", | |
2621 | tty->count, tty_name(tty, buf)); | |
2622 | tty->count = 0; | |
2623 | } | |
37bdfb07 | 2624 | |
1da177e4 LT |
2625 | /* |
2626 | * We've decremented tty->count, so we need to remove this file | |
2627 | * descriptor off the tty->tty_files list; this serves two | |
2628 | * purposes: | |
2629 | * - check_tty_count sees the correct number of file descriptors | |
2630 | * associated with this tty. | |
2631 | * - do_tty_hangup no longer sees this file descriptor as | |
2632 | * something that needs to be handled for hangups. | |
2633 | */ | |
2634 | file_kill(filp); | |
2635 | filp->private_data = NULL; | |
2636 | ||
2637 | /* | |
2638 | * Perform some housekeeping before deciding whether to return. | |
2639 | * | |
2640 | * Set the TTY_CLOSING flag if this was the last open. In the | |
2641 | * case of a pty we may have to wait around for the other side | |
2642 | * to close, and TTY_CLOSING makes sure we can't be reopened. | |
2643 | */ | |
37bdfb07 | 2644 | if (tty_closing) |
1da177e4 | 2645 | set_bit(TTY_CLOSING, &tty->flags); |
37bdfb07 | 2646 | if (o_tty_closing) |
1da177e4 LT |
2647 | set_bit(TTY_CLOSING, &o_tty->flags); |
2648 | ||
2649 | /* | |
2650 | * If _either_ side is closing, make sure there aren't any | |
2651 | * processes that still think tty or o_tty is their controlling | |
2652 | * tty. | |
2653 | */ | |
2654 | if (tty_closing || o_tty_closing) { | |
1da177e4 | 2655 | read_lock(&tasklist_lock); |
24ec839c | 2656 | session_clear_tty(tty->session); |
1da177e4 | 2657 | if (o_tty) |
24ec839c | 2658 | session_clear_tty(o_tty->session); |
1da177e4 LT |
2659 | read_unlock(&tasklist_lock); |
2660 | } | |
2661 | ||
70522e12 | 2662 | mutex_unlock(&tty_mutex); |
da965822 | 2663 | |
1da177e4 LT |
2664 | /* check whether both sides are closing ... */ |
2665 | if (!tty_closing || (o_tty && !o_tty_closing)) | |
2666 | return; | |
37bdfb07 | 2667 | |
1da177e4 LT |
2668 | #ifdef TTY_DEBUG_HANGUP |
2669 | printk(KERN_DEBUG "freeing tty structure..."); | |
2670 | #endif | |
2671 | /* | |
2672 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then | |
2673 | * kill any delayed work. As this is the final close it does not | |
2674 | * race with the set_ldisc code path. | |
2675 | */ | |
2676 | clear_bit(TTY_LDISC, &tty->flags); | |
33f0f88f | 2677 | cancel_delayed_work(&tty->buf.work); |
1da177e4 LT |
2678 | |
2679 | /* | |
33f0f88f | 2680 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 | 2681 | */ |
37bdfb07 | 2682 | |
1da177e4 | 2683 | flush_scheduled_work(); |
37bdfb07 | 2684 | |
1da177e4 LT |
2685 | /* |
2686 | * Wait for any short term users (we know they are just driver | |
2687 | * side waiters as the file is closing so user count on the file | |
2688 | * side is zero. | |
2689 | */ | |
2690 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
37bdfb07 | 2691 | while (tty->ldisc.refcount) { |
1da177e4 LT |
2692 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
2693 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); | |
2694 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2695 | } | |
2696 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2697 | /* | |
2698 | * Shutdown the current line discipline, and reset it to N_TTY. | |
1da177e4 LT |
2699 | * |
2700 | * FIXME: this MUST get fixed for the new reflocking | |
2701 | */ | |
a352def2 AC |
2702 | if (tty->ldisc.ops->close) |
2703 | (tty->ldisc.ops->close)(tty); | |
2704 | tty_ldisc_put(tty->ldisc.ops); | |
37bdfb07 | 2705 | |
1da177e4 LT |
2706 | /* |
2707 | * Switch the line discipline back | |
2708 | */ | |
a352def2 AC |
2709 | WARN_ON(tty_ldisc_get(N_TTY, &ld)); |
2710 | tty_ldisc_assign(tty, &ld); | |
37bdfb07 | 2711 | tty_set_termios_ldisc(tty, N_TTY); |
1da177e4 LT |
2712 | if (o_tty) { |
2713 | /* FIXME: could o_tty be in setldisc here ? */ | |
2714 | clear_bit(TTY_LDISC, &o_tty->flags); | |
a352def2 AC |
2715 | if (o_tty->ldisc.ops->close) |
2716 | (o_tty->ldisc.ops->close)(o_tty); | |
2717 | tty_ldisc_put(o_tty->ldisc.ops); | |
2718 | WARN_ON(tty_ldisc_get(N_TTY, &ld)); | |
2719 | tty_ldisc_assign(o_tty, &ld); | |
37bdfb07 | 2720 | tty_set_termios_ldisc(o_tty, N_TTY); |
1da177e4 LT |
2721 | } |
2722 | /* | |
d5698c28 | 2723 | * The release_tty function takes care of the details of clearing |
1da177e4 LT |
2724 | * the slots and preserving the termios structure. |
2725 | */ | |
d5698c28 | 2726 | release_tty(tty, idx); |
1da177e4 | 2727 | |
1da177e4 | 2728 | /* Make this pty number available for reallocation */ |
718a9163 SB |
2729 | if (devpts) |
2730 | devpts_kill_index(idx); | |
1da177e4 LT |
2731 | } |
2732 | ||
af9b897e AC |
2733 | /** |
2734 | * tty_open - open a tty device | |
2735 | * @inode: inode of device file | |
2736 | * @filp: file pointer to tty | |
1da177e4 | 2737 | * |
af9b897e AC |
2738 | * tty_open and tty_release keep up the tty count that contains the |
2739 | * number of opens done on a tty. We cannot use the inode-count, as | |
2740 | * different inodes might point to the same tty. | |
1da177e4 | 2741 | * |
af9b897e AC |
2742 | * Open-counting is needed for pty masters, as well as for keeping |
2743 | * track of serial lines: DTR is dropped when the last close happens. | |
2744 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
2745 | * | |
2746 | * The termios state of a pty is reset on first open so that | |
2747 | * settings don't persist across reuse. | |
2748 | * | |
24ec839c PZ |
2749 | * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. |
2750 | * tty->count should protect the rest. | |
2751 | * ->siglock protects ->signal/->sighand | |
1da177e4 | 2752 | */ |
af9b897e | 2753 | |
39d95b9d | 2754 | static int __tty_open(struct inode *inode, struct file *filp) |
1da177e4 LT |
2755 | { |
2756 | struct tty_struct *tty; | |
2757 | int noctty, retval; | |
2758 | struct tty_driver *driver; | |
2759 | int index; | |
2760 | dev_t device = inode->i_rdev; | |
2761 | unsigned short saved_flags = filp->f_flags; | |
2762 | ||
2763 | nonseekable_open(inode, filp); | |
37bdfb07 | 2764 | |
1da177e4 LT |
2765 | retry_open: |
2766 | noctty = filp->f_flags & O_NOCTTY; | |
2767 | index = -1; | |
2768 | retval = 0; | |
37bdfb07 | 2769 | |
70522e12 | 2770 | mutex_lock(&tty_mutex); |
1da177e4 | 2771 | |
37bdfb07 | 2772 | if (device == MKDEV(TTYAUX_MAJOR, 0)) { |
24ec839c PZ |
2773 | tty = get_current_tty(); |
2774 | if (!tty) { | |
70522e12 | 2775 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2776 | return -ENXIO; |
2777 | } | |
24ec839c PZ |
2778 | driver = tty->driver; |
2779 | index = tty->index; | |
1da177e4 LT |
2780 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
2781 | /* noctty = 1; */ | |
2782 | goto got_driver; | |
2783 | } | |
2784 | #ifdef CONFIG_VT | |
37bdfb07 | 2785 | if (device == MKDEV(TTY_MAJOR, 0)) { |
1da177e4 LT |
2786 | extern struct tty_driver *console_driver; |
2787 | driver = console_driver; | |
2788 | index = fg_console; | |
2789 | noctty = 1; | |
2790 | goto got_driver; | |
2791 | } | |
2792 | #endif | |
37bdfb07 | 2793 | if (device == MKDEV(TTYAUX_MAJOR, 1)) { |
1da177e4 LT |
2794 | driver = console_device(&index); |
2795 | if (driver) { | |
2796 | /* Don't let /dev/console block */ | |
2797 | filp->f_flags |= O_NONBLOCK; | |
2798 | noctty = 1; | |
2799 | goto got_driver; | |
2800 | } | |
70522e12 | 2801 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2802 | return -ENODEV; |
2803 | } | |
2804 | ||
2805 | driver = get_tty_driver(device, &index); | |
2806 | if (!driver) { | |
70522e12 | 2807 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2808 | return -ENODEV; |
2809 | } | |
2810 | got_driver: | |
2811 | retval = init_dev(driver, index, &tty); | |
70522e12 | 2812 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2813 | if (retval) |
2814 | return retval; | |
2815 | ||
2816 | filp->private_data = tty; | |
2817 | file_move(filp, &tty->tty_files); | |
2818 | check_tty_count(tty, "tty_open"); | |
2819 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2820 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2821 | noctty = 1; | |
2822 | #ifdef TTY_DEBUG_HANGUP | |
2823 | printk(KERN_DEBUG "opening %s...", tty->name); | |
2824 | #endif | |
2825 | if (!retval) { | |
f34d7a5b AC |
2826 | if (tty->ops->open) |
2827 | retval = tty->ops->open(tty, filp); | |
1da177e4 LT |
2828 | else |
2829 | retval = -ENODEV; | |
2830 | } | |
2831 | filp->f_flags = saved_flags; | |
2832 | ||
37bdfb07 AC |
2833 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && |
2834 | !capable(CAP_SYS_ADMIN)) | |
1da177e4 LT |
2835 | retval = -EBUSY; |
2836 | ||
2837 | if (retval) { | |
2838 | #ifdef TTY_DEBUG_HANGUP | |
2839 | printk(KERN_DEBUG "error %d in opening %s...", retval, | |
2840 | tty->name); | |
2841 | #endif | |
2842 | release_dev(filp); | |
2843 | if (retval != -ERESTARTSYS) | |
2844 | return retval; | |
2845 | if (signal_pending(current)) | |
2846 | return retval; | |
2847 | schedule(); | |
2848 | /* | |
2849 | * Need to reset f_op in case a hangup happened. | |
2850 | */ | |
2851 | if (filp->f_op == &hung_up_tty_fops) | |
2852 | filp->f_op = &tty_fops; | |
2853 | goto retry_open; | |
2854 | } | |
24ec839c PZ |
2855 | |
2856 | mutex_lock(&tty_mutex); | |
2857 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2858 | if (!noctty && |
2859 | current->signal->leader && | |
2860 | !current->signal->tty && | |
ab521dc0 | 2861 | tty->session == NULL) |
2a65f1d9 | 2862 | __proc_set_tty(current, tty); |
24ec839c PZ |
2863 | spin_unlock_irq(¤t->sighand->siglock); |
2864 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
2865 | return 0; |
2866 | } | |
2867 | ||
39d95b9d JC |
2868 | /* BKL pushdown: scary code avoidance wrapper */ |
2869 | static int tty_open(struct inode *inode, struct file *filp) | |
2870 | { | |
2871 | int ret; | |
2872 | ||
2873 | lock_kernel(); | |
2874 | ret = __tty_open(inode, filp); | |
2875 | unlock_kernel(); | |
2876 | return ret; | |
2877 | } | |
2878 | ||
2879 | ||
2880 | ||
1da177e4 | 2881 | #ifdef CONFIG_UNIX98_PTYS |
af9b897e AC |
2882 | /** |
2883 | * ptmx_open - open a unix 98 pty master | |
2884 | * @inode: inode of device file | |
2885 | * @filp: file pointer to tty | |
2886 | * | |
2887 | * Allocate a unix98 pty master device from the ptmx driver. | |
2888 | * | |
2889 | * Locking: tty_mutex protects theinit_dev work. tty->count should | |
37bdfb07 | 2890 | * protect the rest. |
af9b897e AC |
2891 | * allocated_ptys_lock handles the list of free pty numbers |
2892 | */ | |
2893 | ||
39d95b9d | 2894 | static int __ptmx_open(struct inode *inode, struct file *filp) |
1da177e4 LT |
2895 | { |
2896 | struct tty_struct *tty; | |
2897 | int retval; | |
2898 | int index; | |
1da177e4 LT |
2899 | |
2900 | nonseekable_open(inode, filp); | |
2901 | ||
2902 | /* find a device that is not in use. */ | |
718a9163 SB |
2903 | index = devpts_new_index(); |
2904 | if (index < 0) | |
2905 | return index; | |
1da177e4 | 2906 | |
70522e12 | 2907 | mutex_lock(&tty_mutex); |
1da177e4 | 2908 | retval = init_dev(ptm_driver, index, &tty); |
70522e12 | 2909 | mutex_unlock(&tty_mutex); |
37bdfb07 | 2910 | |
1da177e4 LT |
2911 | if (retval) |
2912 | goto out; | |
2913 | ||
2914 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
2915 | filp->private_data = tty; | |
2916 | file_move(filp, &tty->tty_files); | |
2917 | ||
4f8f9d66 SB |
2918 | retval = devpts_pty_new(tty->link); |
2919 | if (retval) | |
1da177e4 LT |
2920 | goto out1; |
2921 | ||
86a96538 | 2922 | check_tty_count(tty, "ptmx_open"); |
f34d7a5b | 2923 | retval = ptm_driver->ops->open(tty, filp); |
41126226 | 2924 | if (!retval) |
1da177e4 LT |
2925 | return 0; |
2926 | out1: | |
2927 | release_dev(filp); | |
9453a5ad | 2928 | return retval; |
1da177e4 | 2929 | out: |
718a9163 | 2930 | devpts_kill_index(index); |
1da177e4 LT |
2931 | return retval; |
2932 | } | |
39d95b9d JC |
2933 | |
2934 | static int ptmx_open(struct inode *inode, struct file *filp) | |
2935 | { | |
2936 | int ret; | |
2937 | ||
2938 | lock_kernel(); | |
2939 | ret = __ptmx_open(inode, filp); | |
2940 | unlock_kernel(); | |
2941 | return ret; | |
2942 | } | |
1da177e4 LT |
2943 | #endif |
2944 | ||
af9b897e AC |
2945 | /** |
2946 | * tty_release - vfs callback for close | |
2947 | * @inode: inode of tty | |
2948 | * @filp: file pointer for handle to tty | |
2949 | * | |
2950 | * Called the last time each file handle is closed that references | |
2951 | * this tty. There may however be several such references. | |
2952 | * | |
2953 | * Locking: | |
2954 | * Takes bkl. See release_dev | |
2955 | */ | |
2956 | ||
37bdfb07 | 2957 | static int tty_release(struct inode *inode, struct file *filp) |
1da177e4 LT |
2958 | { |
2959 | lock_kernel(); | |
2960 | release_dev(filp); | |
2961 | unlock_kernel(); | |
2962 | return 0; | |
2963 | } | |
2964 | ||
af9b897e AC |
2965 | /** |
2966 | * tty_poll - check tty status | |
2967 | * @filp: file being polled | |
2968 | * @wait: poll wait structures to update | |
2969 | * | |
2970 | * Call the line discipline polling method to obtain the poll | |
2971 | * status of the device. | |
2972 | * | |
2973 | * Locking: locks called line discipline but ldisc poll method | |
2974 | * may be re-entered freely by other callers. | |
2975 | */ | |
2976 | ||
37bdfb07 | 2977 | static unsigned int tty_poll(struct file *filp, poll_table *wait) |
1da177e4 | 2978 | { |
37bdfb07 | 2979 | struct tty_struct *tty; |
1da177e4 LT |
2980 | struct tty_ldisc *ld; |
2981 | int ret = 0; | |
2982 | ||
2983 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2984 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) |
1da177e4 | 2985 | return 0; |
37bdfb07 | 2986 | |
1da177e4 | 2987 | ld = tty_ldisc_ref_wait(tty); |
a352def2 AC |
2988 | if (ld->ops->poll) |
2989 | ret = (ld->ops->poll)(tty, filp, wait); | |
1da177e4 LT |
2990 | tty_ldisc_deref(ld); |
2991 | return ret; | |
2992 | } | |
2993 | ||
37bdfb07 | 2994 | static int tty_fasync(int fd, struct file *filp, int on) |
1da177e4 | 2995 | { |
37bdfb07 | 2996 | struct tty_struct *tty; |
47f86834 | 2997 | unsigned long flags; |
5d1e3230 | 2998 | int retval = 0; |
1da177e4 | 2999 | |
5d1e3230 | 3000 | lock_kernel(); |
1da177e4 | 3001 | tty = (struct tty_struct *)filp->private_data; |
a7113a96 | 3002 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) |
5d1e3230 | 3003 | goto out; |
37bdfb07 | 3004 | |
1da177e4 LT |
3005 | retval = fasync_helper(fd, filp, on, &tty->fasync); |
3006 | if (retval <= 0) | |
5d1e3230 | 3007 | goto out; |
1da177e4 LT |
3008 | |
3009 | if (on) { | |
ab521dc0 EB |
3010 | enum pid_type type; |
3011 | struct pid *pid; | |
1da177e4 LT |
3012 | if (!waitqueue_active(&tty->read_wait)) |
3013 | tty->minimum_to_wake = 1; | |
47f86834 | 3014 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
ab521dc0 EB |
3015 | if (tty->pgrp) { |
3016 | pid = tty->pgrp; | |
3017 | type = PIDTYPE_PGID; | |
3018 | } else { | |
3019 | pid = task_pid(current); | |
3020 | type = PIDTYPE_PID; | |
3021 | } | |
47f86834 | 3022 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
ab521dc0 | 3023 | retval = __f_setown(filp, pid, type, 0); |
1da177e4 | 3024 | if (retval) |
5d1e3230 | 3025 | goto out; |
1da177e4 LT |
3026 | } else { |
3027 | if (!tty->fasync && !waitqueue_active(&tty->read_wait)) | |
3028 | tty->minimum_to_wake = N_TTY_BUF_SIZE; | |
3029 | } | |
5d1e3230 JC |
3030 | retval = 0; |
3031 | out: | |
3032 | unlock_kernel(); | |
3033 | return retval; | |
1da177e4 LT |
3034 | } |
3035 | ||
af9b897e AC |
3036 | /** |
3037 | * tiocsti - fake input character | |
3038 | * @tty: tty to fake input into | |
3039 | * @p: pointer to character | |
3040 | * | |
3a4fa0a2 | 3041 | * Fake input to a tty device. Does the necessary locking and |
af9b897e AC |
3042 | * input management. |
3043 | * | |
3044 | * FIXME: does not honour flow control ?? | |
3045 | * | |
3046 | * Locking: | |
3047 | * Called functions take tty_ldisc_lock | |
3048 | * current->signal->tty check is safe without locks | |
28298232 AC |
3049 | * |
3050 | * FIXME: may race normal receive processing | |
af9b897e AC |
3051 | */ |
3052 | ||
1da177e4 LT |
3053 | static int tiocsti(struct tty_struct *tty, char __user *p) |
3054 | { | |
3055 | char ch, mbz = 0; | |
3056 | struct tty_ldisc *ld; | |
37bdfb07 | 3057 | |
1da177e4 LT |
3058 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) |
3059 | return -EPERM; | |
3060 | if (get_user(ch, p)) | |
3061 | return -EFAULT; | |
3062 | ld = tty_ldisc_ref_wait(tty); | |
a352def2 | 3063 | ld->ops->receive_buf(tty, &ch, &mbz, 1); |
1da177e4 LT |
3064 | tty_ldisc_deref(ld); |
3065 | return 0; | |
3066 | } | |
3067 | ||
af9b897e AC |
3068 | /** |
3069 | * tiocgwinsz - implement window query ioctl | |
3070 | * @tty; tty | |
3071 | * @arg: user buffer for result | |
3072 | * | |
808a0d38 | 3073 | * Copies the kernel idea of the window size into the user buffer. |
af9b897e | 3074 | * |
24ec839c | 3075 | * Locking: tty->termios_mutex is taken to ensure the winsize data |
808a0d38 | 3076 | * is consistent. |
af9b897e AC |
3077 | */ |
3078 | ||
37bdfb07 | 3079 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) |
1da177e4 | 3080 | { |
808a0d38 AC |
3081 | int err; |
3082 | ||
5785c95b | 3083 | mutex_lock(&tty->termios_mutex); |
808a0d38 | 3084 | err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); |
5785c95b | 3085 | mutex_unlock(&tty->termios_mutex); |
808a0d38 AC |
3086 | |
3087 | return err ? -EFAULT: 0; | |
1da177e4 LT |
3088 | } |
3089 | ||
af9b897e AC |
3090 | /** |
3091 | * tiocswinsz - implement window size set ioctl | |
3092 | * @tty; tty | |
3093 | * @arg: user buffer for result | |
3094 | * | |
3095 | * Copies the user idea of the window size to the kernel. Traditionally | |
3096 | * this is just advisory information but for the Linux console it | |
3097 | * actually has driver level meaning and triggers a VC resize. | |
3098 | * | |
3099 | * Locking: | |
ca9bda00 AC |
3100 | * Called function use the console_sem is used to ensure we do |
3101 | * not try and resize the console twice at once. | |
24ec839c PZ |
3102 | * The tty->termios_mutex is used to ensure we don't double |
3103 | * resize and get confused. Lock order - tty->termios_mutex before | |
ca9bda00 | 3104 | * console sem |
af9b897e AC |
3105 | */ |
3106 | ||
1da177e4 | 3107 | static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, |
37bdfb07 | 3108 | struct winsize __user *arg) |
1da177e4 LT |
3109 | { |
3110 | struct winsize tmp_ws; | |
47f86834 AC |
3111 | struct pid *pgrp, *rpgrp; |
3112 | unsigned long flags; | |
1da177e4 LT |
3113 | |
3114 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
3115 | return -EFAULT; | |
ca9bda00 | 3116 | |
5785c95b | 3117 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 3118 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
ca9bda00 AC |
3119 | goto done; |
3120 | ||
1da177e4 LT |
3121 | #ifdef CONFIG_VT |
3122 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { | |
5785c95b AV |
3123 | if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, |
3124 | tmp_ws.ws_row)) { | |
3125 | mutex_unlock(&tty->termios_mutex); | |
37bdfb07 | 3126 | return -ENXIO; |
ca9bda00 | 3127 | } |
1da177e4 LT |
3128 | } |
3129 | #endif | |
47f86834 AC |
3130 | /* Get the PID values and reference them so we can |
3131 | avoid holding the tty ctrl lock while sending signals */ | |
3132 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
3133 | pgrp = get_pid(tty->pgrp); | |
3134 | rpgrp = get_pid(real_tty->pgrp); | |
3135 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
3136 | ||
3137 | if (pgrp) | |
3138 | kill_pgrp(pgrp, SIGWINCH, 1); | |
3139 | if (rpgrp != pgrp && rpgrp) | |
3140 | kill_pgrp(rpgrp, SIGWINCH, 1); | |
3141 | ||
3142 | put_pid(pgrp); | |
3143 | put_pid(rpgrp); | |
3144 | ||
1da177e4 LT |
3145 | tty->winsize = tmp_ws; |
3146 | real_tty->winsize = tmp_ws; | |
ca9bda00 | 3147 | done: |
5785c95b | 3148 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
3149 | return 0; |
3150 | } | |
3151 | ||
af9b897e AC |
3152 | /** |
3153 | * tioccons - allow admin to move logical console | |
3154 | * @file: the file to become console | |
3155 | * | |
3156 | * Allow the adminstrator to move the redirected console device | |
3157 | * | |
3158 | * Locking: uses redirect_lock to guard the redirect information | |
3159 | */ | |
3160 | ||
1da177e4 LT |
3161 | static int tioccons(struct file *file) |
3162 | { | |
3163 | if (!capable(CAP_SYS_ADMIN)) | |
3164 | return -EPERM; | |
3165 | if (file->f_op->write == redirected_tty_write) { | |
3166 | struct file *f; | |
3167 | spin_lock(&redirect_lock); | |
3168 | f = redirect; | |
3169 | redirect = NULL; | |
3170 | spin_unlock(&redirect_lock); | |
3171 | if (f) | |
3172 | fput(f); | |
3173 | return 0; | |
3174 | } | |
3175 | spin_lock(&redirect_lock); | |
3176 | if (redirect) { | |
3177 | spin_unlock(&redirect_lock); | |
3178 | return -EBUSY; | |
3179 | } | |
3180 | get_file(file); | |
3181 | redirect = file; | |
3182 | spin_unlock(&redirect_lock); | |
3183 | return 0; | |
3184 | } | |
3185 | ||
af9b897e AC |
3186 | /** |
3187 | * fionbio - non blocking ioctl | |
3188 | * @file: file to set blocking value | |
3189 | * @p: user parameter | |
3190 | * | |
3191 | * Historical tty interfaces had a blocking control ioctl before | |
3192 | * the generic functionality existed. This piece of history is preserved | |
3193 | * in the expected tty API of posix OS's. | |
3194 | * | |
3195 | * Locking: none, the open fle handle ensures it won't go away. | |
3196 | */ | |
1da177e4 LT |
3197 | |
3198 | static int fionbio(struct file *file, int __user *p) | |
3199 | { | |
3200 | int nonblock; | |
3201 | ||
3202 | if (get_user(nonblock, p)) | |
3203 | return -EFAULT; | |
3204 | ||
04f378b1 AC |
3205 | /* file->f_flags is still BKL protected in the fs layer - vomit */ |
3206 | lock_kernel(); | |
1da177e4 LT |
3207 | if (nonblock) |
3208 | file->f_flags |= O_NONBLOCK; | |
3209 | else | |
3210 | file->f_flags &= ~O_NONBLOCK; | |
04f378b1 | 3211 | unlock_kernel(); |
1da177e4 LT |
3212 | return 0; |
3213 | } | |
3214 | ||
af9b897e AC |
3215 | /** |
3216 | * tiocsctty - set controlling tty | |
3217 | * @tty: tty structure | |
3218 | * @arg: user argument | |
3219 | * | |
3220 | * This ioctl is used to manage job control. It permits a session | |
3221 | * leader to set this tty as the controlling tty for the session. | |
3222 | * | |
3223 | * Locking: | |
28298232 | 3224 | * Takes tty_mutex() to protect tty instance |
24ec839c PZ |
3225 | * Takes tasklist_lock internally to walk sessions |
3226 | * Takes ->siglock() when updating signal->tty | |
af9b897e AC |
3227 | */ |
3228 | ||
1da177e4 LT |
3229 | static int tiocsctty(struct tty_struct *tty, int arg) |
3230 | { | |
24ec839c | 3231 | int ret = 0; |
ab521dc0 | 3232 | if (current->signal->leader && (task_session(current) == tty->session)) |
24ec839c PZ |
3233 | return ret; |
3234 | ||
3235 | mutex_lock(&tty_mutex); | |
1da177e4 LT |
3236 | /* |
3237 | * The process must be a session leader and | |
3238 | * not have a controlling tty already. | |
3239 | */ | |
24ec839c PZ |
3240 | if (!current->signal->leader || current->signal->tty) { |
3241 | ret = -EPERM; | |
3242 | goto unlock; | |
3243 | } | |
3244 | ||
ab521dc0 | 3245 | if (tty->session) { |
1da177e4 LT |
3246 | /* |
3247 | * This tty is already the controlling | |
3248 | * tty for another session group! | |
3249 | */ | |
37bdfb07 | 3250 | if (arg == 1 && capable(CAP_SYS_ADMIN)) { |
1da177e4 LT |
3251 | /* |
3252 | * Steal it away | |
3253 | */ | |
1da177e4 | 3254 | read_lock(&tasklist_lock); |
24ec839c | 3255 | session_clear_tty(tty->session); |
1da177e4 | 3256 | read_unlock(&tasklist_lock); |
24ec839c PZ |
3257 | } else { |
3258 | ret = -EPERM; | |
3259 | goto unlock; | |
3260 | } | |
1da177e4 | 3261 | } |
24ec839c PZ |
3262 | proc_set_tty(current, tty); |
3263 | unlock: | |
28298232 | 3264 | mutex_unlock(&tty_mutex); |
24ec839c | 3265 | return ret; |
1da177e4 LT |
3266 | } |
3267 | ||
5d0fdf1e AC |
3268 | /** |
3269 | * tty_get_pgrp - return a ref counted pgrp pid | |
3270 | * @tty: tty to read | |
3271 | * | |
3272 | * Returns a refcounted instance of the pid struct for the process | |
3273 | * group controlling the tty. | |
3274 | */ | |
3275 | ||
3276 | struct pid *tty_get_pgrp(struct tty_struct *tty) | |
3277 | { | |
3278 | unsigned long flags; | |
3279 | struct pid *pgrp; | |
3280 | ||
3281 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
3282 | pgrp = get_pid(tty->pgrp); | |
3283 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
3284 | ||
3285 | return pgrp; | |
3286 | } | |
3287 | EXPORT_SYMBOL_GPL(tty_get_pgrp); | |
3288 | ||
af9b897e AC |
3289 | /** |
3290 | * tiocgpgrp - get process group | |
3291 | * @tty: tty passed by user | |
3292 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3293 | * @p: returned pid | |
3294 | * | |
3295 | * Obtain the process group of the tty. If there is no process group | |
3296 | * return an error. | |
3297 | * | |
24ec839c | 3298 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3299 | */ |
3300 | ||
1da177e4 LT |
3301 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3302 | { | |
5d0fdf1e AC |
3303 | struct pid *pid; |
3304 | int ret; | |
1da177e4 LT |
3305 | /* |
3306 | * (tty == real_tty) is a cheap way of | |
3307 | * testing if the tty is NOT a master pty. | |
3308 | */ | |
3309 | if (tty == real_tty && current->signal->tty != real_tty) | |
3310 | return -ENOTTY; | |
5d0fdf1e AC |
3311 | pid = tty_get_pgrp(real_tty); |
3312 | ret = put_user(pid_vnr(pid), p); | |
3313 | put_pid(pid); | |
3314 | return ret; | |
1da177e4 LT |
3315 | } |
3316 | ||
af9b897e AC |
3317 | /** |
3318 | * tiocspgrp - attempt to set process group | |
3319 | * @tty: tty passed by user | |
3320 | * @real_tty: tty side device matching tty passed by user | |
3321 | * @p: pid pointer | |
3322 | * | |
3323 | * Set the process group of the tty to the session passed. Only | |
3324 | * permitted where the tty session is our session. | |
3325 | * | |
47f86834 | 3326 | * Locking: RCU, ctrl lock |
af9b897e AC |
3327 | */ |
3328 | ||
1da177e4 LT |
3329 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3330 | { | |
04a2e6a5 EB |
3331 | struct pid *pgrp; |
3332 | pid_t pgrp_nr; | |
1da177e4 | 3333 | int retval = tty_check_change(real_tty); |
47f86834 | 3334 | unsigned long flags; |
1da177e4 LT |
3335 | |
3336 | if (retval == -EIO) | |
3337 | return -ENOTTY; | |
3338 | if (retval) | |
3339 | return retval; | |
3340 | if (!current->signal->tty || | |
3341 | (current->signal->tty != real_tty) || | |
ab521dc0 | 3342 | (real_tty->session != task_session(current))) |
1da177e4 | 3343 | return -ENOTTY; |
04a2e6a5 | 3344 | if (get_user(pgrp_nr, p)) |
1da177e4 | 3345 | return -EFAULT; |
04a2e6a5 | 3346 | if (pgrp_nr < 0) |
1da177e4 | 3347 | return -EINVAL; |
04a2e6a5 | 3348 | rcu_read_lock(); |
b488893a | 3349 | pgrp = find_vpid(pgrp_nr); |
04a2e6a5 EB |
3350 | retval = -ESRCH; |
3351 | if (!pgrp) | |
3352 | goto out_unlock; | |
3353 | retval = -EPERM; | |
3354 | if (session_of_pgrp(pgrp) != task_session(current)) | |
3355 | goto out_unlock; | |
3356 | retval = 0; | |
47f86834 | 3357 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
ab521dc0 EB |
3358 | put_pid(real_tty->pgrp); |
3359 | real_tty->pgrp = get_pid(pgrp); | |
47f86834 | 3360 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
04a2e6a5 EB |
3361 | out_unlock: |
3362 | rcu_read_unlock(); | |
3363 | return retval; | |
1da177e4 LT |
3364 | } |
3365 | ||
af9b897e AC |
3366 | /** |
3367 | * tiocgsid - get session id | |
3368 | * @tty: tty passed by user | |
3369 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3370 | * @p: pointer to returned session id | |
3371 | * | |
3372 | * Obtain the session id of the tty. If there is no session | |
3373 | * return an error. | |
3374 | * | |
24ec839c | 3375 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3376 | */ |
3377 | ||
1da177e4 LT |
3378 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3379 | { | |
3380 | /* | |
3381 | * (tty == real_tty) is a cheap way of | |
3382 | * testing if the tty is NOT a master pty. | |
3383 | */ | |
3384 | if (tty == real_tty && current->signal->tty != real_tty) | |
3385 | return -ENOTTY; | |
ab521dc0 | 3386 | if (!real_tty->session) |
1da177e4 | 3387 | return -ENOTTY; |
b488893a | 3388 | return put_user(pid_vnr(real_tty->session), p); |
1da177e4 LT |
3389 | } |
3390 | ||
af9b897e AC |
3391 | /** |
3392 | * tiocsetd - set line discipline | |
3393 | * @tty: tty device | |
3394 | * @p: pointer to user data | |
3395 | * | |
3396 | * Set the line discipline according to user request. | |
3397 | * | |
3398 | * Locking: see tty_set_ldisc, this function is just a helper | |
3399 | */ | |
3400 | ||
1da177e4 LT |
3401 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
3402 | { | |
3403 | int ldisc; | |
04f378b1 | 3404 | int ret; |
1da177e4 LT |
3405 | |
3406 | if (get_user(ldisc, p)) | |
3407 | return -EFAULT; | |
04f378b1 AC |
3408 | |
3409 | lock_kernel(); | |
3410 | ret = tty_set_ldisc(tty, ldisc); | |
3411 | unlock_kernel(); | |
3412 | ||
3413 | return ret; | |
1da177e4 LT |
3414 | } |
3415 | ||
af9b897e AC |
3416 | /** |
3417 | * send_break - performed time break | |
3418 | * @tty: device to break on | |
3419 | * @duration: timeout in mS | |
3420 | * | |
3421 | * Perform a timed break on hardware that lacks its own driver level | |
3422 | * timed break functionality. | |
3423 | * | |
3424 | * Locking: | |
28298232 | 3425 | * atomic_write_lock serializes |
af9b897e | 3426 | * |
af9b897e AC |
3427 | */ |
3428 | ||
b20f3ae5 | 3429 | static int send_break(struct tty_struct *tty, unsigned int duration) |
1da177e4 | 3430 | { |
9c1729db | 3431 | if (tty_write_lock(tty, 0) < 0) |
f34d7a5b AC |
3432 | return -EINTR; |
3433 | tty->ops->break_ctl(tty, -1); | |
9c1729db | 3434 | if (!signal_pending(current)) |
b20f3ae5 | 3435 | msleep_interruptible(duration); |
f34d7a5b | 3436 | tty->ops->break_ctl(tty, 0); |
9c1729db | 3437 | tty_write_unlock(tty); |
3e2a078c | 3438 | if (signal_pending(current)) |
f34d7a5b AC |
3439 | return -EINTR; |
3440 | return 0; | |
1da177e4 LT |
3441 | } |
3442 | ||
af9b897e | 3443 | /** |
f34d7a5b | 3444 | * tty_tiocmget - get modem status |
af9b897e AC |
3445 | * @tty: tty device |
3446 | * @file: user file pointer | |
3447 | * @p: pointer to result | |
3448 | * | |
3449 | * Obtain the modem status bits from the tty driver if the feature | |
3450 | * is supported. Return -EINVAL if it is not available. | |
3451 | * | |
3452 | * Locking: none (up to the driver) | |
3453 | */ | |
3454 | ||
3455 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) | |
1da177e4 LT |
3456 | { |
3457 | int retval = -EINVAL; | |
3458 | ||
f34d7a5b AC |
3459 | if (tty->ops->tiocmget) { |
3460 | retval = tty->ops->tiocmget(tty, file); | |
1da177e4 LT |
3461 | |
3462 | if (retval >= 0) | |
3463 | retval = put_user(retval, p); | |
3464 | } | |
3465 | return retval; | |
3466 | } | |
3467 | ||
af9b897e | 3468 | /** |
f34d7a5b | 3469 | * tty_tiocmset - set modem status |
af9b897e AC |
3470 | * @tty: tty device |
3471 | * @file: user file pointer | |
3472 | * @cmd: command - clear bits, set bits or set all | |
3473 | * @p: pointer to desired bits | |
3474 | * | |
3475 | * Set the modem status bits from the tty driver if the feature | |
3476 | * is supported. Return -EINVAL if it is not available. | |
3477 | * | |
3478 | * Locking: none (up to the driver) | |
3479 | */ | |
3480 | ||
3481 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, | |
1da177e4 LT |
3482 | unsigned __user *p) |
3483 | { | |
3484 | int retval = -EINVAL; | |
3485 | ||
f34d7a5b | 3486 | if (tty->ops->tiocmset) { |
1da177e4 LT |
3487 | unsigned int set, clear, val; |
3488 | ||
3489 | retval = get_user(val, p); | |
3490 | if (retval) | |
3491 | return retval; | |
3492 | ||
3493 | set = clear = 0; | |
3494 | switch (cmd) { | |
3495 | case TIOCMBIS: | |
3496 | set = val; | |
3497 | break; | |
3498 | case TIOCMBIC: | |
3499 | clear = val; | |
3500 | break; | |
3501 | case TIOCMSET: | |
3502 | set = val; | |
3503 | clear = ~val; | |
3504 | break; | |
3505 | } | |
3506 | ||
3507 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3508 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3509 | ||
f34d7a5b | 3510 | retval = tty->ops->tiocmset(tty, file, set, clear); |
1da177e4 LT |
3511 | } |
3512 | return retval; | |
3513 | } | |
3514 | ||
3515 | /* | |
3516 | * Split this up, as gcc can choke on it otherwise.. | |
3517 | */ | |
04f378b1 | 3518 | long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
3519 | { |
3520 | struct tty_struct *tty, *real_tty; | |
3521 | void __user *p = (void __user *)arg; | |
3522 | int retval; | |
3523 | struct tty_ldisc *ld; | |
04f378b1 | 3524 | struct inode *inode = file->f_dentry->d_inode; |
37bdfb07 | 3525 | |
1da177e4 LT |
3526 | tty = (struct tty_struct *)file->private_data; |
3527 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3528 | return -EINVAL; | |
3529 | ||
3530 | real_tty = tty; | |
3531 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
3532 | tty->driver->subtype == PTY_TYPE_MASTER) | |
3533 | real_tty = tty->link; | |
3534 | ||
3535 | /* | |
3536 | * Break handling by driver | |
3537 | */ | |
04f378b1 AC |
3538 | |
3539 | retval = -EINVAL; | |
3540 | ||
f34d7a5b | 3541 | if (!tty->ops->break_ctl) { |
37bdfb07 | 3542 | switch (cmd) { |
1da177e4 LT |
3543 | case TIOCSBRK: |
3544 | case TIOCCBRK: | |
f34d7a5b AC |
3545 | if (tty->ops->ioctl) |
3546 | retval = tty->ops->ioctl(tty, file, cmd, arg); | |
3547 | if (retval != -EINVAL && retval != -ENOIOCTLCMD) | |
3548 | printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name); | |
04f378b1 | 3549 | return retval; |
37bdfb07 | 3550 | |
1da177e4 LT |
3551 | /* These two ioctl's always return success; even if */ |
3552 | /* the driver doesn't support them. */ | |
3553 | case TCSBRK: | |
3554 | case TCSBRKP: | |
f34d7a5b | 3555 | if (!tty->ops->ioctl) |
1da177e4 | 3556 | return 0; |
f34d7a5b AC |
3557 | retval = tty->ops->ioctl(tty, file, cmd, arg); |
3558 | if (retval != -EINVAL && retval != -ENOIOCTLCMD) | |
3559 | printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name); | |
1da177e4 LT |
3560 | if (retval == -ENOIOCTLCMD) |
3561 | retval = 0; | |
3562 | return retval; | |
3563 | } | |
3564 | } | |
3565 | ||
3566 | /* | |
3567 | * Factor out some common prep work | |
3568 | */ | |
3569 | switch (cmd) { | |
3570 | case TIOCSETD: | |
3571 | case TIOCSBRK: | |
3572 | case TIOCCBRK: | |
3573 | case TCSBRK: | |
37bdfb07 | 3574 | case TCSBRKP: |
1da177e4 LT |
3575 | retval = tty_check_change(tty); |
3576 | if (retval) | |
3577 | return retval; | |
3578 | if (cmd != TIOCCBRK) { | |
3579 | tty_wait_until_sent(tty, 0); | |
3580 | if (signal_pending(current)) | |
3581 | return -EINTR; | |
3582 | } | |
3583 | break; | |
3584 | } | |
3585 | ||
3586 | switch (cmd) { | |
37bdfb07 AC |
3587 | case TIOCSTI: |
3588 | return tiocsti(tty, p); | |
3589 | case TIOCGWINSZ: | |
3590 | return tiocgwinsz(tty, p); | |
3591 | case TIOCSWINSZ: | |
3592 | return tiocswinsz(tty, real_tty, p); | |
3593 | case TIOCCONS: | |
3594 | return real_tty != tty ? -EINVAL : tioccons(file); | |
3595 | case FIONBIO: | |
3596 | return fionbio(file, p); | |
3597 | case TIOCEXCL: | |
3598 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
3599 | return 0; | |
3600 | case TIOCNXCL: | |
3601 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
3602 | return 0; | |
3603 | case TIOCNOTTY: | |
3604 | if (current->signal->tty != tty) | |
3605 | return -ENOTTY; | |
3606 | no_tty(); | |
3607 | return 0; | |
3608 | case TIOCSCTTY: | |
3609 | return tiocsctty(tty, arg); | |
3610 | case TIOCGPGRP: | |
3611 | return tiocgpgrp(tty, real_tty, p); | |
3612 | case TIOCSPGRP: | |
3613 | return tiocspgrp(tty, real_tty, p); | |
3614 | case TIOCGSID: | |
3615 | return tiocgsid(tty, real_tty, p); | |
3616 | case TIOCGETD: | |
a352def2 | 3617 | return put_user(tty->ldisc.ops->num, (int __user *)p); |
37bdfb07 AC |
3618 | case TIOCSETD: |
3619 | return tiocsetd(tty, p); | |
1da177e4 | 3620 | #ifdef CONFIG_VT |
37bdfb07 AC |
3621 | case TIOCLINUX: |
3622 | return tioclinux(tty, arg); | |
1da177e4 | 3623 | #endif |
37bdfb07 AC |
3624 | /* |
3625 | * Break handling | |
3626 | */ | |
3627 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
f34d7a5b AC |
3628 | if (tty->ops->break_ctl) |
3629 | tty->ops->break_ctl(tty, -1); | |
37bdfb07 | 3630 | return 0; |
1da177e4 | 3631 | |
37bdfb07 | 3632 | case TIOCCBRK: /* Turn break off, unconditionally */ |
f34d7a5b AC |
3633 | if (tty->ops->break_ctl) |
3634 | tty->ops->break_ctl(tty, 0); | |
37bdfb07 AC |
3635 | return 0; |
3636 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
3637 | /* non-zero arg means wait for all output data | |
3638 | * to be sent (performed above) but don't send break. | |
3639 | * This is used by the tcdrain() termios function. | |
3640 | */ | |
3641 | if (!arg) | |
3642 | return send_break(tty, 250); | |
3643 | return 0; | |
3644 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
3645 | return send_break(tty, arg ? arg*100 : 250); | |
3646 | ||
3647 | case TIOCMGET: | |
3648 | return tty_tiocmget(tty, file, p); | |
3649 | case TIOCMSET: | |
3650 | case TIOCMBIC: | |
3651 | case TIOCMBIS: | |
3652 | return tty_tiocmset(tty, file, cmd, p); | |
3653 | case TCFLSH: | |
3654 | switch (arg) { | |
3655 | case TCIFLUSH: | |
3656 | case TCIOFLUSH: | |
3657 | /* flush tty buffer and allow ldisc to process ioctl */ | |
3658 | tty_buffer_flush(tty); | |
c5c34d48 | 3659 | break; |
37bdfb07 AC |
3660 | } |
3661 | break; | |
1da177e4 | 3662 | } |
f34d7a5b AC |
3663 | if (tty->ops->ioctl) { |
3664 | retval = (tty->ops->ioctl)(tty, file, cmd, arg); | |
1da177e4 LT |
3665 | if (retval != -ENOIOCTLCMD) |
3666 | return retval; | |
3667 | } | |
3668 | ld = tty_ldisc_ref_wait(tty); | |
3669 | retval = -EINVAL; | |
a352def2 AC |
3670 | if (ld->ops->ioctl) { |
3671 | retval = ld->ops->ioctl(tty, file, cmd, arg); | |
1da177e4 LT |
3672 | if (retval == -ENOIOCTLCMD) |
3673 | retval = -EINVAL; | |
3674 | } | |
3675 | tty_ldisc_deref(ld); | |
3676 | return retval; | |
3677 | } | |
3678 | ||
e10cc1df | 3679 | #ifdef CONFIG_COMPAT |
37bdfb07 | 3680 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
e10cc1df PF |
3681 | unsigned long arg) |
3682 | { | |
3683 | struct inode *inode = file->f_dentry->d_inode; | |
3684 | struct tty_struct *tty = file->private_data; | |
3685 | struct tty_ldisc *ld; | |
3686 | int retval = -ENOIOCTLCMD; | |
3687 | ||
3688 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3689 | return -EINVAL; | |
3690 | ||
f34d7a5b AC |
3691 | if (tty->ops->compat_ioctl) { |
3692 | retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg); | |
e10cc1df PF |
3693 | if (retval != -ENOIOCTLCMD) |
3694 | return retval; | |
3695 | } | |
3696 | ||
3697 | ld = tty_ldisc_ref_wait(tty); | |
a352def2 AC |
3698 | if (ld->ops->compat_ioctl) |
3699 | retval = ld->ops->compat_ioctl(tty, file, cmd, arg); | |
e10cc1df PF |
3700 | tty_ldisc_deref(ld); |
3701 | ||
3702 | return retval; | |
3703 | } | |
3704 | #endif | |
1da177e4 LT |
3705 | |
3706 | /* | |
3707 | * This implements the "Secure Attention Key" --- the idea is to | |
3708 | * prevent trojan horses by killing all processes associated with this | |
3709 | * tty when the user hits the "Secure Attention Key". Required for | |
3710 | * super-paranoid applications --- see the Orange Book for more details. | |
37bdfb07 | 3711 | * |
1da177e4 LT |
3712 | * This code could be nicer; ideally it should send a HUP, wait a few |
3713 | * seconds, then send a INT, and then a KILL signal. But you then | |
3714 | * have to coordinate with the init process, since all processes associated | |
3715 | * with the current tty must be dead before the new getty is allowed | |
3716 | * to spawn. | |
3717 | * | |
3718 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
3719 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
3720 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
3721 | * | |
3722 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
3723 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
3724 | */ | |
8b6312f4 | 3725 | void __do_SAK(struct tty_struct *tty) |
1da177e4 LT |
3726 | { |
3727 | #ifdef TTY_SOFT_SAK | |
3728 | tty_hangup(tty); | |
3729 | #else | |
652486fb | 3730 | struct task_struct *g, *p; |
ab521dc0 | 3731 | struct pid *session; |
1da177e4 LT |
3732 | int i; |
3733 | struct file *filp; | |
badf1662 | 3734 | struct fdtable *fdt; |
37bdfb07 | 3735 | |
1da177e4 LT |
3736 | if (!tty) |
3737 | return; | |
24ec839c | 3738 | session = tty->session; |
37bdfb07 | 3739 | |
b3f13deb | 3740 | tty_ldisc_flush(tty); |
1da177e4 | 3741 | |
f34d7a5b | 3742 | tty_driver_flush_buffer(tty); |
37bdfb07 | 3743 | |
1da177e4 | 3744 | read_lock(&tasklist_lock); |
652486fb | 3745 | /* Kill the entire session */ |
ab521dc0 | 3746 | do_each_pid_task(session, PIDTYPE_SID, p) { |
652486fb | 3747 | printk(KERN_NOTICE "SAK: killed process %d" |
a47afb0f | 3748 | " (%s): task_session_nr(p)==tty->session\n", |
ba25f9dc | 3749 | task_pid_nr(p), p->comm); |
652486fb | 3750 | send_sig(SIGKILL, p, 1); |
ab521dc0 | 3751 | } while_each_pid_task(session, PIDTYPE_SID, p); |
652486fb EB |
3752 | /* Now kill any processes that happen to have the |
3753 | * tty open. | |
3754 | */ | |
3755 | do_each_thread(g, p) { | |
3756 | if (p->signal->tty == tty) { | |
1da177e4 | 3757 | printk(KERN_NOTICE "SAK: killed process %d" |
a47afb0f | 3758 | " (%s): task_session_nr(p)==tty->session\n", |
ba25f9dc | 3759 | task_pid_nr(p), p->comm); |
1da177e4 LT |
3760 | send_sig(SIGKILL, p, 1); |
3761 | continue; | |
3762 | } | |
3763 | task_lock(p); | |
3764 | if (p->files) { | |
ca99c1da DS |
3765 | /* |
3766 | * We don't take a ref to the file, so we must | |
3767 | * hold ->file_lock instead. | |
3768 | */ | |
3769 | spin_lock(&p->files->file_lock); | |
badf1662 | 3770 | fdt = files_fdtable(p->files); |
37bdfb07 | 3771 | for (i = 0; i < fdt->max_fds; i++) { |
1da177e4 LT |
3772 | filp = fcheck_files(p->files, i); |
3773 | if (!filp) | |
3774 | continue; | |
3775 | if (filp->f_op->read == tty_read && | |
3776 | filp->private_data == tty) { | |
3777 | printk(KERN_NOTICE "SAK: killed process %d" | |
3778 | " (%s): fd#%d opened to the tty\n", | |
ba25f9dc | 3779 | task_pid_nr(p), p->comm, i); |
20ac9437 | 3780 | force_sig(SIGKILL, p); |
1da177e4 LT |
3781 | break; |
3782 | } | |
3783 | } | |
ca99c1da | 3784 | spin_unlock(&p->files->file_lock); |
1da177e4 LT |
3785 | } |
3786 | task_unlock(p); | |
652486fb | 3787 | } while_each_thread(g, p); |
1da177e4 LT |
3788 | read_unlock(&tasklist_lock); |
3789 | #endif | |
3790 | } | |
3791 | ||
8b6312f4 EB |
3792 | static void do_SAK_work(struct work_struct *work) |
3793 | { | |
3794 | struct tty_struct *tty = | |
3795 | container_of(work, struct tty_struct, SAK_work); | |
3796 | __do_SAK(tty); | |
3797 | } | |
3798 | ||
1da177e4 LT |
3799 | /* |
3800 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
3801 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
3802 | * the values which we write to it will be identical to the values which it | |
3803 | * already has. --akpm | |
3804 | */ | |
3805 | void do_SAK(struct tty_struct *tty) | |
3806 | { | |
3807 | if (!tty) | |
3808 | return; | |
1da177e4 LT |
3809 | schedule_work(&tty->SAK_work); |
3810 | } | |
3811 | ||
3812 | EXPORT_SYMBOL(do_SAK); | |
3813 | ||
af9b897e AC |
3814 | /** |
3815 | * flush_to_ldisc | |
65f27f38 | 3816 | * @work: tty structure passed from work queue. |
af9b897e AC |
3817 | * |
3818 | * This routine is called out of the software interrupt to flush data | |
3819 | * from the buffer chain to the line discipline. | |
3820 | * | |
3821 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
3822 | * while invoking the line discipline receive_buf method. The | |
3823 | * receive_buf method is single threaded for each tty instance. | |
1da177e4 | 3824 | */ |
37bdfb07 | 3825 | |
65f27f38 | 3826 | static void flush_to_ldisc(struct work_struct *work) |
1da177e4 | 3827 | { |
65f27f38 DH |
3828 | struct tty_struct *tty = |
3829 | container_of(work, struct tty_struct, buf.work.work); | |
1da177e4 LT |
3830 | unsigned long flags; |
3831 | struct tty_ldisc *disc; | |
2c3bb20f | 3832 | struct tty_buffer *tbuf, *head; |
8977d929 PF |
3833 | char *char_buf; |
3834 | unsigned char *flag_buf; | |
1da177e4 LT |
3835 | |
3836 | disc = tty_ldisc_ref(tty); | |
3837 | if (disc == NULL) /* !TTY_LDISC */ | |
3838 | return; | |
3839 | ||
808249ce | 3840 | spin_lock_irqsave(&tty->buf.lock, flags); |
37bdfb07 AC |
3841 | /* So we know a flush is running */ |
3842 | set_bit(TTY_FLUSHING, &tty->flags); | |
2c3bb20f PF |
3843 | head = tty->buf.head; |
3844 | if (head != NULL) { | |
3845 | tty->buf.head = NULL; | |
3846 | for (;;) { | |
3847 | int count = head->commit - head->read; | |
3848 | if (!count) { | |
3849 | if (head->next == NULL) | |
3850 | break; | |
3851 | tbuf = head; | |
3852 | head = head->next; | |
3853 | tty_buffer_free(tty, tbuf); | |
3854 | continue; | |
3855 | } | |
42fd552e AC |
3856 | /* Ldisc or user is trying to flush the buffers |
3857 | we are feeding to the ldisc, stop feeding the | |
3858 | line discipline as we want to empty the queue */ | |
3859 | if (test_bit(TTY_FLUSHPENDING, &tty->flags)) | |
3860 | break; | |
2c3bb20f PF |
3861 | if (!tty->receive_room) { |
3862 | schedule_delayed_work(&tty->buf.work, 1); | |
3863 | break; | |
3864 | } | |
3865 | if (count > tty->receive_room) | |
3866 | count = tty->receive_room; | |
3867 | char_buf = head->char_buf_ptr + head->read; | |
3868 | flag_buf = head->flag_buf_ptr + head->read; | |
3869 | head->read += count; | |
8977d929 | 3870 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
a352def2 AC |
3871 | disc->ops->receive_buf(tty, char_buf, |
3872 | flag_buf, count); | |
8977d929 PF |
3873 | spin_lock_irqsave(&tty->buf.lock, flags); |
3874 | } | |
42fd552e | 3875 | /* Restore the queue head */ |
2c3bb20f | 3876 | tty->buf.head = head; |
33f0f88f | 3877 | } |
42fd552e AC |
3878 | /* We may have a deferred request to flush the input buffer, |
3879 | if so pull the chain under the lock and empty the queue */ | |
3880 | if (test_bit(TTY_FLUSHPENDING, &tty->flags)) { | |
3881 | __tty_buffer_flush(tty); | |
3882 | clear_bit(TTY_FLUSHPENDING, &tty->flags); | |
3883 | wake_up(&tty->read_wait); | |
3884 | } | |
3885 | clear_bit(TTY_FLUSHING, &tty->flags); | |
808249ce | 3886 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
817d6d3b | 3887 | |
1da177e4 LT |
3888 | tty_ldisc_deref(disc); |
3889 | } | |
3890 | ||
1da177e4 LT |
3891 | /** |
3892 | * tty_flip_buffer_push - terminal | |
3893 | * @tty: tty to push | |
3894 | * | |
3895 | * Queue a push of the terminal flip buffers to the line discipline. This | |
3896 | * function must not be called from IRQ context if tty->low_latency is set. | |
3897 | * | |
3898 | * In the event of the queue being busy for flipping the work will be | |
3899 | * held off and retried later. | |
af9b897e AC |
3900 | * |
3901 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
1da177e4 LT |
3902 | */ |
3903 | ||
3904 | void tty_flip_buffer_push(struct tty_struct *tty) | |
3905 | { | |
808249ce PF |
3906 | unsigned long flags; |
3907 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 3908 | if (tty->buf.tail != NULL) |
8977d929 | 3909 | tty->buf.tail->commit = tty->buf.tail->used; |
808249ce PF |
3910 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3911 | ||
1da177e4 | 3912 | if (tty->low_latency) |
65f27f38 | 3913 | flush_to_ldisc(&tty->buf.work.work); |
1da177e4 | 3914 | else |
33f0f88f | 3915 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
3916 | } |
3917 | ||
3918 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
3919 | ||
33f0f88f | 3920 | |
af9b897e AC |
3921 | /** |
3922 | * initialize_tty_struct | |
3923 | * @tty: tty to initialize | |
3924 | * | |
3925 | * This subroutine initializes a tty structure that has been newly | |
3926 | * allocated. | |
3927 | * | |
3928 | * Locking: none - tty in question must not be exposed at this point | |
1da177e4 | 3929 | */ |
af9b897e | 3930 | |
1da177e4 LT |
3931 | static void initialize_tty_struct(struct tty_struct *tty) |
3932 | { | |
a352def2 | 3933 | struct tty_ldisc ld; |
1da177e4 LT |
3934 | memset(tty, 0, sizeof(struct tty_struct)); |
3935 | tty->magic = TTY_MAGIC; | |
a352def2 AC |
3936 | if (tty_ldisc_get(N_TTY, &ld) < 0) |
3937 | panic("n_tty: init_tty"); | |
3938 | tty_ldisc_assign(tty, &ld); | |
ab521dc0 EB |
3939 | tty->session = NULL; |
3940 | tty->pgrp = NULL; | |
1da177e4 | 3941 | tty->overrun_time = jiffies; |
33f0f88f AC |
3942 | tty->buf.head = tty->buf.tail = NULL; |
3943 | tty_buffer_init(tty); | |
65f27f38 | 3944 | INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); |
5785c95b | 3945 | mutex_init(&tty->termios_mutex); |
1da177e4 LT |
3946 | init_waitqueue_head(&tty->write_wait); |
3947 | init_waitqueue_head(&tty->read_wait); | |
65f27f38 | 3948 | INIT_WORK(&tty->hangup_work, do_tty_hangup); |
70522e12 IM |
3949 | mutex_init(&tty->atomic_read_lock); |
3950 | mutex_init(&tty->atomic_write_lock); | |
1da177e4 | 3951 | spin_lock_init(&tty->read_lock); |
04f378b1 | 3952 | spin_lock_init(&tty->ctrl_lock); |
1da177e4 | 3953 | INIT_LIST_HEAD(&tty->tty_files); |
7f1f86a0 | 3954 | INIT_WORK(&tty->SAK_work, do_SAK_work); |
1da177e4 LT |
3955 | } |
3956 | ||
f34d7a5b AC |
3957 | /** |
3958 | * tty_put_char - write one character to a tty | |
3959 | * @tty: tty | |
3960 | * @ch: character | |
3961 | * | |
3962 | * Write one byte to the tty using the provided put_char method | |
3963 | * if present. Returns the number of characters successfully output. | |
3964 | * | |
3965 | * Note: the specific put_char operation in the driver layer may go | |
3966 | * away soon. Don't call it directly, use this method | |
1da177e4 | 3967 | */ |
af9b897e | 3968 | |
f34d7a5b | 3969 | int tty_put_char(struct tty_struct *tty, unsigned char ch) |
1da177e4 | 3970 | { |
f34d7a5b AC |
3971 | if (tty->ops->put_char) |
3972 | return tty->ops->put_char(tty, ch); | |
3973 | return tty->ops->write(tty, &ch, 1); | |
1da177e4 LT |
3974 | } |
3975 | ||
f34d7a5b AC |
3976 | EXPORT_SYMBOL_GPL(tty_put_char); |
3977 | ||
7fe845d1 | 3978 | static struct class *tty_class; |
1da177e4 LT |
3979 | |
3980 | /** | |
af9b897e AC |
3981 | * tty_register_device - register a tty device |
3982 | * @driver: the tty driver that describes the tty device | |
3983 | * @index: the index in the tty driver for this tty device | |
3984 | * @device: a struct device that is associated with this tty device. | |
3985 | * This field is optional, if there is no known struct device | |
3986 | * for this tty device it can be set to NULL safely. | |
1da177e4 | 3987 | * |
01107d34 GKH |
3988 | * Returns a pointer to the struct device for this tty device |
3989 | * (or ERR_PTR(-EFOO) on error). | |
1cdcb6b4 | 3990 | * |
af9b897e AC |
3991 | * This call is required to be made to register an individual tty device |
3992 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
3993 | * that bit is not set, this function should not be called by a tty | |
3994 | * driver. | |
3995 | * | |
3996 | * Locking: ?? | |
1da177e4 | 3997 | */ |
af9b897e | 3998 | |
01107d34 GKH |
3999 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
4000 | struct device *device) | |
1da177e4 LT |
4001 | { |
4002 | char name[64]; | |
4003 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; | |
4004 | ||
4005 | if (index >= driver->num) { | |
4006 | printk(KERN_ERR "Attempt to register invalid tty line number " | |
4007 | " (%d).\n", index); | |
1cdcb6b4 | 4008 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
4009 | } |
4010 | ||
1da177e4 LT |
4011 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
4012 | pty_line_name(driver, index, name); | |
4013 | else | |
4014 | tty_line_name(driver, index, name); | |
1cdcb6b4 | 4015 | |
01107d34 | 4016 | return device_create(tty_class, device, dev, name); |
1da177e4 LT |
4017 | } |
4018 | ||
4019 | /** | |
af9b897e AC |
4020 | * tty_unregister_device - unregister a tty device |
4021 | * @driver: the tty driver that describes the tty device | |
4022 | * @index: the index in the tty driver for this tty device | |
1da177e4 | 4023 | * |
af9b897e AC |
4024 | * If a tty device is registered with a call to tty_register_device() then |
4025 | * this function must be called when the tty device is gone. | |
4026 | * | |
4027 | * Locking: ?? | |
1da177e4 | 4028 | */ |
af9b897e | 4029 | |
1da177e4 LT |
4030 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
4031 | { | |
37bdfb07 AC |
4032 | device_destroy(tty_class, |
4033 | MKDEV(driver->major, driver->minor_start) + index); | |
1da177e4 LT |
4034 | } |
4035 | ||
4036 | EXPORT_SYMBOL(tty_register_device); | |
4037 | EXPORT_SYMBOL(tty_unregister_device); | |
4038 | ||
4039 | struct tty_driver *alloc_tty_driver(int lines) | |
4040 | { | |
4041 | struct tty_driver *driver; | |
4042 | ||
506eb99a | 4043 | driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); |
1da177e4 | 4044 | if (driver) { |
1da177e4 LT |
4045 | driver->magic = TTY_DRIVER_MAGIC; |
4046 | driver->num = lines; | |
4047 | /* later we'll move allocation of tables here */ | |
4048 | } | |
4049 | return driver; | |
4050 | } | |
4051 | ||
4052 | void put_tty_driver(struct tty_driver *driver) | |
4053 | { | |
4054 | kfree(driver); | |
4055 | } | |
4056 | ||
b68e31d0 JD |
4057 | void tty_set_operations(struct tty_driver *driver, |
4058 | const struct tty_operations *op) | |
1da177e4 | 4059 | { |
f34d7a5b AC |
4060 | driver->ops = op; |
4061 | }; | |
1da177e4 LT |
4062 | |
4063 | EXPORT_SYMBOL(alloc_tty_driver); | |
4064 | EXPORT_SYMBOL(put_tty_driver); | |
4065 | EXPORT_SYMBOL(tty_set_operations); | |
4066 | ||
4067 | /* | |
4068 | * Called by a tty driver to register itself. | |
4069 | */ | |
4070 | int tty_register_driver(struct tty_driver *driver) | |
4071 | { | |
4072 | int error; | |
37bdfb07 | 4073 | int i; |
1da177e4 LT |
4074 | dev_t dev; |
4075 | void **p = NULL; | |
4076 | ||
4077 | if (driver->flags & TTY_DRIVER_INSTALLED) | |
4078 | return 0; | |
4079 | ||
543691a6 AW |
4080 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { |
4081 | p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); | |
1da177e4 LT |
4082 | if (!p) |
4083 | return -ENOMEM; | |
1da177e4 LT |
4084 | } |
4085 | ||
4086 | if (!driver->major) { | |
37bdfb07 AC |
4087 | error = alloc_chrdev_region(&dev, driver->minor_start, |
4088 | driver->num, driver->name); | |
1da177e4 LT |
4089 | if (!error) { |
4090 | driver->major = MAJOR(dev); | |
4091 | driver->minor_start = MINOR(dev); | |
4092 | } | |
4093 | } else { | |
4094 | dev = MKDEV(driver->major, driver->minor_start); | |
e5717c48 | 4095 | error = register_chrdev_region(dev, driver->num, driver->name); |
1da177e4 LT |
4096 | } |
4097 | if (error < 0) { | |
4098 | kfree(p); | |
4099 | return error; | |
4100 | } | |
4101 | ||
4102 | if (p) { | |
4103 | driver->ttys = (struct tty_struct **)p; | |
edc6afc5 | 4104 | driver->termios = (struct ktermios **)(p + driver->num); |
37bdfb07 AC |
4105 | driver->termios_locked = (struct ktermios **) |
4106 | (p + driver->num * 2); | |
1da177e4 LT |
4107 | } else { |
4108 | driver->ttys = NULL; | |
4109 | driver->termios = NULL; | |
4110 | driver->termios_locked = NULL; | |
4111 | } | |
4112 | ||
4113 | cdev_init(&driver->cdev, &tty_fops); | |
4114 | driver->cdev.owner = driver->owner; | |
4115 | error = cdev_add(&driver->cdev, dev, driver->num); | |
4116 | if (error) { | |
1da177e4 LT |
4117 | unregister_chrdev_region(dev, driver->num); |
4118 | driver->ttys = NULL; | |
4119 | driver->termios = driver->termios_locked = NULL; | |
4120 | kfree(p); | |
4121 | return error; | |
4122 | } | |
4123 | ||
ca509f69 | 4124 | mutex_lock(&tty_mutex); |
1da177e4 | 4125 | list_add(&driver->tty_drivers, &tty_drivers); |
ca509f69 | 4126 | mutex_unlock(&tty_mutex); |
37bdfb07 AC |
4127 | |
4128 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { | |
4129 | for (i = 0; i < driver->num; i++) | |
1da177e4 LT |
4130 | tty_register_device(driver, i, NULL); |
4131 | } | |
4132 | proc_tty_register_driver(driver); | |
4133 | return 0; | |
4134 | } | |
4135 | ||
4136 | EXPORT_SYMBOL(tty_register_driver); | |
4137 | ||
4138 | /* | |
4139 | * Called by a tty driver to unregister itself. | |
4140 | */ | |
4141 | int tty_unregister_driver(struct tty_driver *driver) | |
4142 | { | |
4143 | int i; | |
edc6afc5 | 4144 | struct ktermios *tp; |
1da177e4 LT |
4145 | void *p; |
4146 | ||
4147 | if (driver->refcount) | |
4148 | return -EBUSY; | |
4149 | ||
4150 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
4151 | driver->num); | |
ca509f69 | 4152 | mutex_lock(&tty_mutex); |
1da177e4 | 4153 | list_del(&driver->tty_drivers); |
ca509f69 | 4154 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
4155 | |
4156 | /* | |
4157 | * Free the termios and termios_locked structures because | |
4158 | * we don't want to get memory leaks when modular tty | |
4159 | * drivers are removed from the kernel. | |
4160 | */ | |
4161 | for (i = 0; i < driver->num; i++) { | |
4162 | tp = driver->termios[i]; | |
4163 | if (tp) { | |
4164 | driver->termios[i] = NULL; | |
4165 | kfree(tp); | |
4166 | } | |
4167 | tp = driver->termios_locked[i]; | |
4168 | if (tp) { | |
4169 | driver->termios_locked[i] = NULL; | |
4170 | kfree(tp); | |
4171 | } | |
331b8319 | 4172 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
1da177e4 LT |
4173 | tty_unregister_device(driver, i); |
4174 | } | |
4175 | p = driver->ttys; | |
4176 | proc_tty_unregister_driver(driver); | |
4177 | driver->ttys = NULL; | |
4178 | driver->termios = driver->termios_locked = NULL; | |
4179 | kfree(p); | |
4180 | cdev_del(&driver->cdev); | |
4181 | return 0; | |
4182 | } | |
1da177e4 LT |
4183 | EXPORT_SYMBOL(tty_unregister_driver); |
4184 | ||
24ec839c PZ |
4185 | dev_t tty_devnum(struct tty_struct *tty) |
4186 | { | |
4187 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
4188 | } | |
4189 | EXPORT_SYMBOL(tty_devnum); | |
4190 | ||
4191 | void proc_clear_tty(struct task_struct *p) | |
4192 | { | |
4193 | spin_lock_irq(&p->sighand->siglock); | |
4194 | p->signal->tty = NULL; | |
4195 | spin_unlock_irq(&p->sighand->siglock); | |
4196 | } | |
7cac4ce5 | 4197 | EXPORT_SYMBOL(proc_clear_tty); |
24ec839c | 4198 | |
47f86834 AC |
4199 | /* Called under the sighand lock */ |
4200 | ||
2a65f1d9 | 4201 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
4202 | { |
4203 | if (tty) { | |
47f86834 AC |
4204 | unsigned long flags; |
4205 | /* We should not have a session or pgrp to put here but.... */ | |
4206 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
d9c1e9a8 EB |
4207 | put_pid(tty->session); |
4208 | put_pid(tty->pgrp); | |
ab521dc0 | 4209 | tty->pgrp = get_pid(task_pgrp(tsk)); |
47f86834 AC |
4210 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
4211 | tty->session = get_pid(task_session(tsk)); | |
24ec839c | 4212 | } |
2a65f1d9 | 4213 | put_pid(tsk->signal->tty_old_pgrp); |
24ec839c | 4214 | tsk->signal->tty = tty; |
ab521dc0 | 4215 | tsk->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
4216 | } |
4217 | ||
98a27ba4 | 4218 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
4219 | { |
4220 | spin_lock_irq(&tsk->sighand->siglock); | |
2a65f1d9 | 4221 | __proc_set_tty(tsk, tty); |
24ec839c PZ |
4222 | spin_unlock_irq(&tsk->sighand->siglock); |
4223 | } | |
4224 | ||
4225 | struct tty_struct *get_current_tty(void) | |
4226 | { | |
4227 | struct tty_struct *tty; | |
4228 | WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); | |
4229 | tty = current->signal->tty; | |
4230 | /* | |
4231 | * session->tty can be changed/cleared from under us, make sure we | |
4232 | * issue the load. The obtained pointer, when not NULL, is valid as | |
4233 | * long as we hold tty_mutex. | |
4234 | */ | |
4235 | barrier(); | |
4236 | return tty; | |
4237 | } | |
a311f743 | 4238 | EXPORT_SYMBOL_GPL(get_current_tty); |
1da177e4 LT |
4239 | |
4240 | /* | |
4241 | * Initialize the console device. This is called *early*, so | |
4242 | * we can't necessarily depend on lots of kernel help here. | |
4243 | * Just do some early initializations, and do the complex setup | |
4244 | * later. | |
4245 | */ | |
4246 | void __init console_init(void) | |
4247 | { | |
4248 | initcall_t *call; | |
4249 | ||
4250 | /* Setup the default TTY line discipline. */ | |
4251 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); | |
4252 | ||
4253 | /* | |
37bdfb07 | 4254 | * set up the console device so that later boot sequences can |
1da177e4 LT |
4255 | * inform about problems etc.. |
4256 | */ | |
1da177e4 LT |
4257 | call = __con_initcall_start; |
4258 | while (call < __con_initcall_end) { | |
4259 | (*call)(); | |
4260 | call++; | |
4261 | } | |
4262 | } | |
4263 | ||
1da177e4 LT |
4264 | static int __init tty_class_init(void) |
4265 | { | |
7fe845d1 | 4266 | tty_class = class_create(THIS_MODULE, "tty"); |
1da177e4 LT |
4267 | if (IS_ERR(tty_class)) |
4268 | return PTR_ERR(tty_class); | |
4269 | return 0; | |
4270 | } | |
4271 | ||
4272 | postcore_initcall(tty_class_init); | |
4273 | ||
4274 | /* 3/2004 jmc: why do these devices exist? */ | |
4275 | ||
4276 | static struct cdev tty_cdev, console_cdev; | |
4277 | #ifdef CONFIG_UNIX98_PTYS | |
4278 | static struct cdev ptmx_cdev; | |
4279 | #endif | |
4280 | #ifdef CONFIG_VT | |
4281 | static struct cdev vc0_cdev; | |
4282 | #endif | |
4283 | ||
4284 | /* | |
4285 | * Ok, now we can initialize the rest of the tty devices and can count | |
4286 | * on memory allocations, interrupts etc.. | |
4287 | */ | |
4288 | static int __init tty_init(void) | |
4289 | { | |
4290 | cdev_init(&tty_cdev, &tty_fops); | |
4291 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
4292 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
4293 | panic("Couldn't register /dev/tty driver\n"); | |
01107d34 | 4294 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty"); |
1da177e4 LT |
4295 | |
4296 | cdev_init(&console_cdev, &console_fops); | |
4297 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
4298 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
4299 | panic("Couldn't register /dev/console driver\n"); | |
01107d34 | 4300 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console"); |
1da177e4 LT |
4301 | |
4302 | #ifdef CONFIG_UNIX98_PTYS | |
4303 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
4304 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
4305 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
4306 | panic("Couldn't register /dev/ptmx driver\n"); | |
01107d34 | 4307 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); |
1da177e4 LT |
4308 | #endif |
4309 | ||
4310 | #ifdef CONFIG_VT | |
4311 | cdev_init(&vc0_cdev, &console_fops); | |
4312 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || | |
4313 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) | |
4314 | panic("Couldn't register /dev/tty0 driver\n"); | |
01107d34 | 4315 | device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); |
1da177e4 LT |
4316 | |
4317 | vty_init(); | |
4318 | #endif | |
4319 | return 0; | |
4320 | } | |
4321 | module_init(tty_init); |