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> | |
81 | #include <linux/console.h> | |
82 | #include <linux/timer.h> | |
83 | #include <linux/ctype.h> | |
84 | #include <linux/kd.h> | |
85 | #include <linux/mm.h> | |
86 | #include <linux/string.h> | |
87 | #include <linux/slab.h> | |
88 | #include <linux/poll.h> | |
89 | #include <linux/proc_fs.h> | |
90 | #include <linux/init.h> | |
91 | #include <linux/module.h> | |
92 | #include <linux/smp_lock.h> | |
93 | #include <linux/device.h> | |
94 | #include <linux/idr.h> | |
95 | #include <linux/wait.h> | |
96 | #include <linux/bitops.h> | |
b20f3ae5 | 97 | #include <linux/delay.h> |
1da177e4 LT |
98 | |
99 | #include <asm/uaccess.h> | |
100 | #include <asm/system.h> | |
101 | ||
102 | #include <linux/kbd_kern.h> | |
103 | #include <linux/vt_kern.h> | |
104 | #include <linux/selection.h> | |
1da177e4 LT |
105 | |
106 | #include <linux/kmod.h> | |
b488893a | 107 | #include <linux/nsproxy.h> |
1da177e4 LT |
108 | |
109 | #undef TTY_DEBUG_HANGUP | |
110 | ||
111 | #define TTY_PARANOIA_CHECK 1 | |
112 | #define CHECK_TTY_COUNT 1 | |
113 | ||
edc6afc5 | 114 | struct ktermios tty_std_termios = { /* for the benefit of tty drivers */ |
1da177e4 LT |
115 | .c_iflag = ICRNL | IXON, |
116 | .c_oflag = OPOST | ONLCR, | |
117 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, | |
118 | .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | | |
119 | ECHOCTL | ECHOKE | IEXTEN, | |
edc6afc5 AC |
120 | .c_cc = INIT_C_CC, |
121 | .c_ispeed = 38400, | |
122 | .c_ospeed = 38400 | |
1da177e4 LT |
123 | }; |
124 | ||
125 | EXPORT_SYMBOL(tty_std_termios); | |
126 | ||
127 | /* This list gets poked at by procfs and various bits of boot up code. This | |
128 | could do with some rationalisation such as pulling the tty proc function | |
129 | into this file */ | |
37bdfb07 | 130 | |
1da177e4 LT |
131 | LIST_HEAD(tty_drivers); /* linked list of tty drivers */ |
132 | ||
24ec839c | 133 | /* Mutex to protect creating and releasing a tty. This is shared with |
1da177e4 | 134 | vt.c for deeply disgusting hack reasons */ |
70522e12 | 135 | DEFINE_MUTEX(tty_mutex); |
de2a84f2 | 136 | EXPORT_SYMBOL(tty_mutex); |
1da177e4 LT |
137 | |
138 | #ifdef CONFIG_UNIX98_PTYS | |
139 | extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ | |
37bdfb07 | 140 | extern int pty_limit; /* Config limit on Unix98 ptys */ |
1da177e4 | 141 | static DEFINE_IDR(allocated_ptys); |
a6752f3f | 142 | static DEFINE_MUTEX(allocated_ptys_lock); |
1da177e4 LT |
143 | static int ptmx_open(struct inode *, struct file *); |
144 | #endif | |
145 | ||
1da177e4 LT |
146 | static void initialize_tty_struct(struct tty_struct *tty); |
147 | ||
148 | static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); | |
149 | static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); | |
37bdfb07 AC |
150 | ssize_t redirected_tty_write(struct file *, const char __user *, |
151 | size_t, loff_t *); | |
1da177e4 LT |
152 | static unsigned int tty_poll(struct file *, poll_table *); |
153 | static int tty_open(struct inode *, struct file *); | |
154 | static int tty_release(struct inode *, struct file *); | |
04f378b1 | 155 | long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg); |
e10cc1df | 156 | #ifdef CONFIG_COMPAT |
37bdfb07 | 157 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
e10cc1df PF |
158 | unsigned long arg); |
159 | #else | |
160 | #define tty_compat_ioctl NULL | |
161 | #endif | |
37bdfb07 | 162 | static int tty_fasync(int fd, struct file *filp, int on); |
d5698c28 | 163 | static void release_tty(struct tty_struct *tty, int idx); |
2a65f1d9 | 164 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
98a27ba4 | 165 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
1da177e4 | 166 | |
af9b897e AC |
167 | /** |
168 | * alloc_tty_struct - allocate a tty object | |
169 | * | |
170 | * Return a new empty tty structure. The data fields have not | |
171 | * been initialized in any way but has been zeroed | |
172 | * | |
173 | * Locking: none | |
af9b897e | 174 | */ |
1da177e4 LT |
175 | |
176 | static struct tty_struct *alloc_tty_struct(void) | |
177 | { | |
1266b1e1 | 178 | return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); |
1da177e4 LT |
179 | } |
180 | ||
33f0f88f AC |
181 | static void tty_buffer_free_all(struct tty_struct *); |
182 | ||
af9b897e AC |
183 | /** |
184 | * free_tty_struct - free a disused tty | |
185 | * @tty: tty struct to free | |
186 | * | |
187 | * Free the write buffers, tty queue and tty memory itself. | |
188 | * | |
189 | * Locking: none. Must be called after tty is definitely unused | |
190 | */ | |
191 | ||
1da177e4 LT |
192 | static inline void free_tty_struct(struct tty_struct *tty) |
193 | { | |
194 | kfree(tty->write_buf); | |
33f0f88f | 195 | tty_buffer_free_all(tty); |
1da177e4 LT |
196 | kfree(tty); |
197 | } | |
198 | ||
199 | #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) | |
200 | ||
af9b897e AC |
201 | /** |
202 | * tty_name - return tty naming | |
203 | * @tty: tty structure | |
204 | * @buf: buffer for output | |
205 | * | |
206 | * Convert a tty structure into a name. The name reflects the kernel | |
207 | * naming policy and if udev is in use may not reflect user space | |
208 | * | |
209 | * Locking: none | |
210 | */ | |
211 | ||
1da177e4 LT |
212 | char *tty_name(struct tty_struct *tty, char *buf) |
213 | { | |
214 | if (!tty) /* Hmm. NULL pointer. That's fun. */ | |
215 | strcpy(buf, "NULL tty"); | |
216 | else | |
217 | strcpy(buf, tty->name); | |
218 | return buf; | |
219 | } | |
220 | ||
221 | EXPORT_SYMBOL(tty_name); | |
222 | ||
d769a669 | 223 | int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, |
1da177e4 LT |
224 | const char *routine) |
225 | { | |
226 | #ifdef TTY_PARANOIA_CHECK | |
227 | if (!tty) { | |
228 | printk(KERN_WARNING | |
229 | "null TTY for (%d:%d) in %s\n", | |
230 | imajor(inode), iminor(inode), routine); | |
231 | return 1; | |
232 | } | |
233 | if (tty->magic != TTY_MAGIC) { | |
234 | printk(KERN_WARNING | |
235 | "bad magic number for tty struct (%d:%d) in %s\n", | |
236 | imajor(inode), iminor(inode), routine); | |
237 | return 1; | |
238 | } | |
239 | #endif | |
240 | return 0; | |
241 | } | |
242 | ||
243 | static int check_tty_count(struct tty_struct *tty, const char *routine) | |
244 | { | |
245 | #ifdef CHECK_TTY_COUNT | |
246 | struct list_head *p; | |
247 | int count = 0; | |
37bdfb07 | 248 | |
1da177e4 LT |
249 | file_list_lock(); |
250 | list_for_each(p, &tty->tty_files) { | |
251 | count++; | |
252 | } | |
253 | file_list_unlock(); | |
254 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
255 | tty->driver->subtype == PTY_TYPE_SLAVE && | |
256 | tty->link && tty->link->count) | |
257 | count++; | |
258 | if (tty->count != count) { | |
259 | printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " | |
260 | "!= #fd's(%d) in %s\n", | |
261 | tty->name, tty->count, count, routine); | |
262 | return count; | |
24ec839c | 263 | } |
1da177e4 LT |
264 | #endif |
265 | return 0; | |
266 | } | |
267 | ||
33f0f88f AC |
268 | /* |
269 | * Tty buffer allocation management | |
270 | */ | |
271 | ||
af9b897e AC |
272 | /** |
273 | * tty_buffer_free_all - free buffers used by a tty | |
274 | * @tty: tty to free from | |
275 | * | |
276 | * Remove all the buffers pending on a tty whether queued with data | |
277 | * or in the free ring. Must be called when the tty is no longer in use | |
278 | * | |
279 | * Locking: none | |
280 | */ | |
281 | ||
33f0f88f AC |
282 | static void tty_buffer_free_all(struct tty_struct *tty) |
283 | { | |
284 | struct tty_buffer *thead; | |
37bdfb07 | 285 | while ((thead = tty->buf.head) != NULL) { |
33f0f88f AC |
286 | tty->buf.head = thead->next; |
287 | kfree(thead); | |
288 | } | |
37bdfb07 | 289 | while ((thead = tty->buf.free) != NULL) { |
33f0f88f AC |
290 | tty->buf.free = thead->next; |
291 | kfree(thead); | |
292 | } | |
293 | tty->buf.tail = NULL; | |
01da5fd8 | 294 | tty->buf.memory_used = 0; |
33f0f88f AC |
295 | } |
296 | ||
01da5fd8 AC |
297 | /** |
298 | * tty_buffer_init - prepare a tty buffer structure | |
299 | * @tty: tty to initialise | |
300 | * | |
301 | * Set up the initial state of the buffer management for a tty device. | |
302 | * Must be called before the other tty buffer functions are used. | |
303 | * | |
304 | * Locking: none | |
305 | */ | |
306 | ||
33f0f88f AC |
307 | static void tty_buffer_init(struct tty_struct *tty) |
308 | { | |
808249ce | 309 | spin_lock_init(&tty->buf.lock); |
33f0f88f AC |
310 | tty->buf.head = NULL; |
311 | tty->buf.tail = NULL; | |
312 | tty->buf.free = NULL; | |
01da5fd8 | 313 | tty->buf.memory_used = 0; |
33f0f88f AC |
314 | } |
315 | ||
01da5fd8 AC |
316 | /** |
317 | * tty_buffer_alloc - allocate a tty buffer | |
318 | * @tty: tty device | |
319 | * @size: desired size (characters) | |
320 | * | |
321 | * Allocate a new tty buffer to hold the desired number of characters. | |
322 | * Return NULL if out of memory or the allocation would exceed the | |
323 | * per device queue | |
324 | * | |
325 | * Locking: Caller must hold tty->buf.lock | |
326 | */ | |
327 | ||
328 | static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) | |
33f0f88f | 329 | { |
01da5fd8 AC |
330 | struct tty_buffer *p; |
331 | ||
332 | if (tty->buf.memory_used + size > 65536) | |
333 | return NULL; | |
334 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); | |
37bdfb07 | 335 | if (p == NULL) |
33f0f88f AC |
336 | return NULL; |
337 | p->used = 0; | |
338 | p->size = size; | |
339 | p->next = NULL; | |
8977d929 PF |
340 | p->commit = 0; |
341 | p->read = 0; | |
33f0f88f AC |
342 | p->char_buf_ptr = (char *)(p->data); |
343 | p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; | |
01da5fd8 | 344 | tty->buf.memory_used += size; |
33f0f88f AC |
345 | return p; |
346 | } | |
347 | ||
01da5fd8 AC |
348 | /** |
349 | * tty_buffer_free - free a tty buffer | |
350 | * @tty: tty owning the buffer | |
351 | * @b: the buffer to free | |
352 | * | |
353 | * Free a tty buffer, or add it to the free list according to our | |
354 | * internal strategy | |
355 | * | |
356 | * Locking: Caller must hold tty->buf.lock | |
357 | */ | |
33f0f88f AC |
358 | |
359 | static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) | |
360 | { | |
361 | /* Dumb strategy for now - should keep some stats */ | |
01da5fd8 AC |
362 | tty->buf.memory_used -= b->size; |
363 | WARN_ON(tty->buf.memory_used < 0); | |
364 | ||
37bdfb07 | 365 | if (b->size >= 512) |
33f0f88f AC |
366 | kfree(b); |
367 | else { | |
368 | b->next = tty->buf.free; | |
369 | tty->buf.free = b; | |
370 | } | |
371 | } | |
372 | ||
c5c34d48 | 373 | /** |
42fd552e | 374 | * __tty_buffer_flush - flush full tty buffers |
c5c34d48 PF |
375 | * @tty: tty to flush |
376 | * | |
42fd552e AC |
377 | * flush all the buffers containing receive data. Caller must |
378 | * hold the buffer lock and must have ensured no parallel flush to | |
379 | * ldisc is running. | |
c5c34d48 | 380 | * |
42fd552e | 381 | * Locking: Caller must hold tty->buf.lock |
c5c34d48 PF |
382 | */ |
383 | ||
42fd552e | 384 | static void __tty_buffer_flush(struct tty_struct *tty) |
c5c34d48 PF |
385 | { |
386 | struct tty_buffer *thead; | |
c5c34d48 | 387 | |
37bdfb07 | 388 | while ((thead = tty->buf.head) != NULL) { |
c5c34d48 PF |
389 | tty->buf.head = thead->next; |
390 | tty_buffer_free(tty, thead); | |
391 | } | |
392 | tty->buf.tail = NULL; | |
42fd552e AC |
393 | } |
394 | ||
395 | /** | |
396 | * tty_buffer_flush - flush full tty buffers | |
397 | * @tty: tty to flush | |
398 | * | |
399 | * flush all the buffers containing receive data. If the buffer is | |
400 | * being processed by flush_to_ldisc then we defer the processing | |
401 | * to that function | |
402 | * | |
403 | * Locking: none | |
404 | */ | |
405 | ||
406 | static void tty_buffer_flush(struct tty_struct *tty) | |
407 | { | |
408 | unsigned long flags; | |
409 | spin_lock_irqsave(&tty->buf.lock, flags); | |
410 | ||
411 | /* If the data is being pushed to the tty layer then we can't | |
412 | process it here. Instead set a flag and the flush_to_ldisc | |
413 | path will process the flush request before it exits */ | |
414 | if (test_bit(TTY_FLUSHING, &tty->flags)) { | |
415 | set_bit(TTY_FLUSHPENDING, &tty->flags); | |
416 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
417 | wait_event(tty->read_wait, | |
418 | test_bit(TTY_FLUSHPENDING, &tty->flags) == 0); | |
419 | return; | |
420 | } else | |
421 | __tty_buffer_flush(tty); | |
c5c34d48 PF |
422 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
423 | } | |
424 | ||
01da5fd8 AC |
425 | /** |
426 | * tty_buffer_find - find a free tty buffer | |
427 | * @tty: tty owning the buffer | |
428 | * @size: characters wanted | |
429 | * | |
430 | * Locate an existing suitable tty buffer or if we are lacking one then | |
431 | * allocate a new one. We round our buffers off in 256 character chunks | |
432 | * to get better allocation behaviour. | |
433 | * | |
434 | * Locking: Caller must hold tty->buf.lock | |
435 | */ | |
436 | ||
33f0f88f AC |
437 | static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) |
438 | { | |
439 | struct tty_buffer **tbh = &tty->buf.free; | |
37bdfb07 | 440 | while ((*tbh) != NULL) { |
33f0f88f | 441 | struct tty_buffer *t = *tbh; |
37bdfb07 | 442 | if (t->size >= size) { |
33f0f88f AC |
443 | *tbh = t->next; |
444 | t->next = NULL; | |
445 | t->used = 0; | |
8977d929 PF |
446 | t->commit = 0; |
447 | t->read = 0; | |
01da5fd8 | 448 | tty->buf.memory_used += t->size; |
33f0f88f AC |
449 | return t; |
450 | } | |
451 | tbh = &((*tbh)->next); | |
452 | } | |
453 | /* Round the buffer size out */ | |
37bdfb07 | 454 | size = (size + 0xFF) & ~0xFF; |
01da5fd8 | 455 | return tty_buffer_alloc(tty, size); |
33f0f88f AC |
456 | /* Should possibly check if this fails for the largest buffer we |
457 | have queued and recycle that ? */ | |
458 | } | |
459 | ||
01da5fd8 AC |
460 | /** |
461 | * tty_buffer_request_room - grow tty buffer if needed | |
462 | * @tty: tty structure | |
463 | * @size: size desired | |
464 | * | |
465 | * Make at least size bytes of linear space available for the tty | |
466 | * buffer. If we fail return the size we managed to find. | |
467 | * | |
468 | * Locking: Takes tty->buf.lock | |
469 | */ | |
33f0f88f AC |
470 | int tty_buffer_request_room(struct tty_struct *tty, size_t size) |
471 | { | |
808249ce PF |
472 | struct tty_buffer *b, *n; |
473 | int left; | |
474 | unsigned long flags; | |
475 | ||
476 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33f0f88f AC |
477 | |
478 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to | |
479 | remove this conditional if its worth it. This would be invisible | |
480 | to the callers */ | |
33b37a33 | 481 | if ((b = tty->buf.tail) != NULL) |
33f0f88f | 482 | left = b->size - b->used; |
33b37a33 | 483 | else |
808249ce PF |
484 | left = 0; |
485 | ||
486 | if (left < size) { | |
487 | /* This is the slow path - looking for new buffers to use */ | |
488 | if ((n = tty_buffer_find(tty, size)) != NULL) { | |
489 | if (b != NULL) { | |
490 | b->next = n; | |
8977d929 | 491 | b->commit = b->used; |
808249ce PF |
492 | } else |
493 | tty->buf.head = n; | |
494 | tty->buf.tail = n; | |
808249ce PF |
495 | } else |
496 | size = left; | |
497 | } | |
498 | ||
499 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
33f0f88f AC |
500 | return size; |
501 | } | |
33f0f88f AC |
502 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
503 | ||
af9b897e AC |
504 | /** |
505 | * tty_insert_flip_string - Add characters to the tty buffer | |
506 | * @tty: tty structure | |
507 | * @chars: characters | |
508 | * @size: size | |
509 | * | |
510 | * Queue a series of bytes to the tty buffering. All the characters | |
511 | * passed are marked as without error. Returns the number added. | |
512 | * | |
513 | * Locking: Called functions may take tty->buf.lock | |
514 | */ | |
515 | ||
e1a25090 AM |
516 | int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, |
517 | size_t size) | |
33f0f88f AC |
518 | { |
519 | int copied = 0; | |
520 | do { | |
521 | int space = tty_buffer_request_room(tty, size - copied); | |
522 | struct tty_buffer *tb = tty->buf.tail; | |
523 | /* If there is no space then tb may be NULL */ | |
37bdfb07 | 524 | if (unlikely(space == 0)) |
33f0f88f AC |
525 | break; |
526 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
527 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
528 | tb->used += space; | |
529 | copied += space; | |
530 | chars += space; | |
527063ba AD |
531 | /* There is a small chance that we need to split the data over |
532 | several buffers. If this is the case we must loop */ | |
533 | } while (unlikely(size > copied)); | |
33f0f88f AC |
534 | return copied; |
535 | } | |
ee37df78 | 536 | EXPORT_SYMBOL(tty_insert_flip_string); |
33f0f88f | 537 | |
af9b897e AC |
538 | /** |
539 | * tty_insert_flip_string_flags - Add characters to the tty buffer | |
540 | * @tty: tty structure | |
541 | * @chars: characters | |
542 | * @flags: flag bytes | |
543 | * @size: size | |
544 | * | |
545 | * Queue a series of bytes to the tty buffering. For each character | |
546 | * the flags array indicates the status of the character. Returns the | |
547 | * number added. | |
548 | * | |
549 | * Locking: Called functions may take tty->buf.lock | |
550 | */ | |
551 | ||
e1a25090 AM |
552 | int tty_insert_flip_string_flags(struct tty_struct *tty, |
553 | const unsigned char *chars, const char *flags, size_t size) | |
33f0f88f AC |
554 | { |
555 | int copied = 0; | |
556 | do { | |
557 | int space = tty_buffer_request_room(tty, size - copied); | |
558 | struct tty_buffer *tb = tty->buf.tail; | |
559 | /* If there is no space then tb may be NULL */ | |
37bdfb07 | 560 | if (unlikely(space == 0)) |
33f0f88f AC |
561 | break; |
562 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
563 | memcpy(tb->flag_buf_ptr + tb->used, flags, space); | |
564 | tb->used += space; | |
565 | copied += space; | |
566 | chars += space; | |
567 | flags += space; | |
527063ba AD |
568 | /* There is a small chance that we need to split the data over |
569 | several buffers. If this is the case we must loop */ | |
570 | } while (unlikely(size > copied)); | |
33f0f88f AC |
571 | return copied; |
572 | } | |
ff4547f4 | 573 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
33f0f88f | 574 | |
af9b897e AC |
575 | /** |
576 | * tty_schedule_flip - push characters to ldisc | |
577 | * @tty: tty to push from | |
578 | * | |
579 | * Takes any pending buffers and transfers their ownership to the | |
580 | * ldisc side of the queue. It then schedules those characters for | |
581 | * processing by the line discipline. | |
582 | * | |
583 | * Locking: Takes tty->buf.lock | |
584 | */ | |
585 | ||
e1a25090 AM |
586 | void tty_schedule_flip(struct tty_struct *tty) |
587 | { | |
588 | unsigned long flags; | |
589 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 590 | if (tty->buf.tail != NULL) |
e1a25090 | 591 | tty->buf.tail->commit = tty->buf.tail->used; |
e1a25090 AM |
592 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
593 | schedule_delayed_work(&tty->buf.work, 1); | |
594 | } | |
595 | EXPORT_SYMBOL(tty_schedule_flip); | |
33f0f88f | 596 | |
af9b897e AC |
597 | /** |
598 | * tty_prepare_flip_string - make room for characters | |
599 | * @tty: tty | |
600 | * @chars: return pointer for character write area | |
601 | * @size: desired size | |
602 | * | |
33f0f88f AC |
603 | * Prepare a block of space in the buffer for data. Returns the length |
604 | * available and buffer pointer to the space which is now allocated and | |
605 | * accounted for as ready for normal characters. This is used for drivers | |
606 | * that need their own block copy routines into the buffer. There is no | |
607 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
608 | * |
609 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
610 | */ |
611 | ||
37bdfb07 AC |
612 | int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, |
613 | size_t size) | |
33f0f88f AC |
614 | { |
615 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
616 | if (likely(space)) { |
617 | struct tty_buffer *tb = tty->buf.tail; | |
618 | *chars = tb->char_buf_ptr + tb->used; | |
619 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
620 | tb->used += space; | |
621 | } | |
33f0f88f AC |
622 | return space; |
623 | } | |
624 | ||
625 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); | |
626 | ||
af9b897e AC |
627 | /** |
628 | * tty_prepare_flip_string_flags - make room for characters | |
629 | * @tty: tty | |
630 | * @chars: return pointer for character write area | |
631 | * @flags: return pointer for status flag write area | |
632 | * @size: desired size | |
633 | * | |
33f0f88f AC |
634 | * Prepare a block of space in the buffer for data. Returns the length |
635 | * available and buffer pointer to the space which is now allocated and | |
636 | * accounted for as ready for characters. This is used for drivers | |
637 | * that need their own block copy routines into the buffer. There is no | |
638 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
639 | * |
640 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
641 | */ |
642 | ||
37bdfb07 AC |
643 | int tty_prepare_flip_string_flags(struct tty_struct *tty, |
644 | unsigned char **chars, char **flags, size_t size) | |
33f0f88f AC |
645 | { |
646 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
647 | if (likely(space)) { |
648 | struct tty_buffer *tb = tty->buf.tail; | |
649 | *chars = tb->char_buf_ptr + tb->used; | |
650 | *flags = tb->flag_buf_ptr + tb->used; | |
651 | tb->used += space; | |
652 | } | |
33f0f88f AC |
653 | return space; |
654 | } | |
655 | ||
656 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); | |
657 | ||
658 | ||
659 | ||
af9b897e AC |
660 | /** |
661 | * tty_set_termios_ldisc - set ldisc field | |
662 | * @tty: tty structure | |
663 | * @num: line discipline number | |
664 | * | |
1da177e4 | 665 | * This is probably overkill for real world processors but |
37bdfb07 | 666 | * they are not on hot paths so a little discipline won't do |
1da177e4 | 667 | * any harm. |
af9b897e | 668 | * |
24ec839c | 669 | * Locking: takes termios_mutex |
1da177e4 | 670 | */ |
37bdfb07 | 671 | |
1da177e4 LT |
672 | static void tty_set_termios_ldisc(struct tty_struct *tty, int num) |
673 | { | |
5785c95b | 674 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 675 | tty->termios->c_line = num; |
5785c95b | 676 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
677 | } |
678 | ||
679 | /* | |
680 | * This guards the refcounted line discipline lists. The lock | |
681 | * must be taken with irqs off because there are hangup path | |
682 | * callers who will do ldisc lookups and cannot sleep. | |
683 | */ | |
37bdfb07 | 684 | |
1da177e4 LT |
685 | static DEFINE_SPINLOCK(tty_ldisc_lock); |
686 | static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); | |
37bdfb07 AC |
687 | /* Line disc dispatch table */ |
688 | static struct tty_ldisc tty_ldiscs[NR_LDISCS]; | |
1da177e4 | 689 | |
af9b897e AC |
690 | /** |
691 | * tty_register_ldisc - install a line discipline | |
692 | * @disc: ldisc number | |
693 | * @new_ldisc: pointer to the ldisc object | |
694 | * | |
695 | * Installs a new line discipline into the kernel. The discipline | |
696 | * is set up as unreferenced and then made available to the kernel | |
697 | * from this point onwards. | |
698 | * | |
699 | * Locking: | |
700 | * takes tty_ldisc_lock to guard against ldisc races | |
701 | */ | |
702 | ||
1da177e4 LT |
703 | int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) |
704 | { | |
705 | unsigned long flags; | |
706 | int ret = 0; | |
37bdfb07 | 707 | |
1da177e4 LT |
708 | if (disc < N_TTY || disc >= NR_LDISCS) |
709 | return -EINVAL; | |
37bdfb07 | 710 | |
1da177e4 | 711 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
bfb07599 AD |
712 | tty_ldiscs[disc] = *new_ldisc; |
713 | tty_ldiscs[disc].num = disc; | |
714 | tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; | |
715 | tty_ldiscs[disc].refcount = 0; | |
1da177e4 | 716 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
37bdfb07 | 717 | |
1da177e4 LT |
718 | return ret; |
719 | } | |
1da177e4 LT |
720 | EXPORT_SYMBOL(tty_register_ldisc); |
721 | ||
af9b897e AC |
722 | /** |
723 | * tty_unregister_ldisc - unload a line discipline | |
724 | * @disc: ldisc number | |
725 | * @new_ldisc: pointer to the ldisc object | |
726 | * | |
727 | * Remove a line discipline from the kernel providing it is not | |
728 | * currently in use. | |
729 | * | |
730 | * Locking: | |
731 | * takes tty_ldisc_lock to guard against ldisc races | |
732 | */ | |
733 | ||
bfb07599 AD |
734 | int tty_unregister_ldisc(int disc) |
735 | { | |
736 | unsigned long flags; | |
737 | int ret = 0; | |
738 | ||
739 | if (disc < N_TTY || disc >= NR_LDISCS) | |
740 | return -EINVAL; | |
741 | ||
742 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
743 | if (tty_ldiscs[disc].refcount) | |
744 | ret = -EBUSY; | |
745 | else | |
746 | tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; | |
747 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
748 | ||
749 | return ret; | |
750 | } | |
751 | EXPORT_SYMBOL(tty_unregister_ldisc); | |
752 | ||
af9b897e AC |
753 | /** |
754 | * tty_ldisc_get - take a reference to an ldisc | |
755 | * @disc: ldisc number | |
756 | * | |
757 | * Takes a reference to a line discipline. Deals with refcounts and | |
758 | * module locking counts. Returns NULL if the discipline is not available. | |
759 | * Returns a pointer to the discipline and bumps the ref count if it is | |
760 | * available | |
761 | * | |
762 | * Locking: | |
763 | * takes tty_ldisc_lock to guard against ldisc races | |
764 | */ | |
765 | ||
1da177e4 LT |
766 | struct tty_ldisc *tty_ldisc_get(int disc) |
767 | { | |
768 | unsigned long flags; | |
769 | struct tty_ldisc *ld; | |
770 | ||
771 | if (disc < N_TTY || disc >= NR_LDISCS) | |
772 | return NULL; | |
37bdfb07 | 773 | |
1da177e4 LT |
774 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
775 | ||
776 | ld = &tty_ldiscs[disc]; | |
777 | /* Check the entry is defined */ | |
37bdfb07 | 778 | if (ld->flags & LDISC_FLAG_DEFINED) { |
1da177e4 LT |
779 | /* If the module is being unloaded we can't use it */ |
780 | if (!try_module_get(ld->owner)) | |
37bdfb07 | 781 | ld = NULL; |
1da177e4 LT |
782 | else /* lock it */ |
783 | ld->refcount++; | |
37bdfb07 | 784 | } else |
1da177e4 LT |
785 | ld = NULL; |
786 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
787 | return ld; | |
788 | } | |
789 | ||
790 | EXPORT_SYMBOL_GPL(tty_ldisc_get); | |
791 | ||
af9b897e AC |
792 | /** |
793 | * tty_ldisc_put - drop ldisc reference | |
794 | * @disc: ldisc number | |
795 | * | |
796 | * Drop a reference to a line discipline. Manage refcounts and | |
797 | * module usage counts | |
798 | * | |
799 | * Locking: | |
800 | * takes tty_ldisc_lock to guard against ldisc races | |
801 | */ | |
802 | ||
1da177e4 LT |
803 | void tty_ldisc_put(int disc) |
804 | { | |
805 | struct tty_ldisc *ld; | |
806 | unsigned long flags; | |
37bdfb07 | 807 | |
56ee4827 | 808 | BUG_ON(disc < N_TTY || disc >= NR_LDISCS); |
37bdfb07 | 809 | |
1da177e4 LT |
810 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
811 | ld = &tty_ldiscs[disc]; | |
56ee4827 ES |
812 | BUG_ON(ld->refcount == 0); |
813 | ld->refcount--; | |
1da177e4 LT |
814 | module_put(ld->owner); |
815 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
816 | } | |
37bdfb07 | 817 | |
1da177e4 LT |
818 | EXPORT_SYMBOL_GPL(tty_ldisc_put); |
819 | ||
af9b897e AC |
820 | /** |
821 | * tty_ldisc_assign - set ldisc on a tty | |
822 | * @tty: tty to assign | |
823 | * @ld: line discipline | |
824 | * | |
825 | * Install an instance of a line discipline into a tty structure. The | |
826 | * ldisc must have a reference count above zero to ensure it remains/ | |
827 | * The tty instance refcount starts at zero. | |
828 | * | |
829 | * Locking: | |
830 | * Caller must hold references | |
831 | */ | |
832 | ||
1da177e4 LT |
833 | static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) |
834 | { | |
835 | tty->ldisc = *ld; | |
836 | tty->ldisc.refcount = 0; | |
837 | } | |
838 | ||
839 | /** | |
840 | * tty_ldisc_try - internal helper | |
841 | * @tty: the tty | |
842 | * | |
843 | * Make a single attempt to grab and bump the refcount on | |
844 | * the tty ldisc. Return 0 on failure or 1 on success. This is | |
845 | * used to implement both the waiting and non waiting versions | |
846 | * of tty_ldisc_ref | |
af9b897e AC |
847 | * |
848 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
849 | */ |
850 | ||
851 | static int tty_ldisc_try(struct tty_struct *tty) | |
852 | { | |
853 | unsigned long flags; | |
854 | struct tty_ldisc *ld; | |
855 | int ret = 0; | |
37bdfb07 | 856 | |
1da177e4 LT |
857 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
858 | ld = &tty->ldisc; | |
37bdfb07 | 859 | if (test_bit(TTY_LDISC, &tty->flags)) { |
1da177e4 LT |
860 | ld->refcount++; |
861 | ret = 1; | |
862 | } | |
863 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
864 | return ret; | |
865 | } | |
866 | ||
867 | /** | |
868 | * tty_ldisc_ref_wait - wait for the tty ldisc | |
869 | * @tty: tty device | |
870 | * | |
37bdfb07 AC |
871 | * Dereference the line discipline for the terminal and take a |
872 | * reference to it. If the line discipline is in flux then | |
1da177e4 LT |
873 | * wait patiently until it changes. |
874 | * | |
875 | * Note: Must not be called from an IRQ/timer context. The caller | |
876 | * must also be careful not to hold other locks that will deadlock | |
877 | * against a discipline change, such as an existing ldisc reference | |
878 | * (which we check for) | |
af9b897e AC |
879 | * |
880 | * Locking: call functions take tty_ldisc_lock | |
1da177e4 | 881 | */ |
37bdfb07 | 882 | |
1da177e4 LT |
883 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) |
884 | { | |
885 | /* wait_event is a macro */ | |
886 | wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); | |
37bdfb07 | 887 | if (tty->ldisc.refcount == 0) |
1da177e4 LT |
888 | printk(KERN_ERR "tty_ldisc_ref_wait\n"); |
889 | return &tty->ldisc; | |
890 | } | |
891 | ||
892 | EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); | |
893 | ||
894 | /** | |
895 | * tty_ldisc_ref - get the tty ldisc | |
896 | * @tty: tty device | |
897 | * | |
37bdfb07 AC |
898 | * Dereference the line discipline for the terminal and take a |
899 | * reference to it. If the line discipline is in flux then | |
1da177e4 | 900 | * return NULL. Can be called from IRQ and timer functions. |
af9b897e AC |
901 | * |
902 | * Locking: called functions take tty_ldisc_lock | |
1da177e4 | 903 | */ |
37bdfb07 | 904 | |
1da177e4 LT |
905 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) |
906 | { | |
37bdfb07 | 907 | if (tty_ldisc_try(tty)) |
1da177e4 LT |
908 | return &tty->ldisc; |
909 | return NULL; | |
910 | } | |
911 | ||
912 | EXPORT_SYMBOL_GPL(tty_ldisc_ref); | |
913 | ||
914 | /** | |
915 | * tty_ldisc_deref - free a tty ldisc reference | |
916 | * @ld: reference to free up | |
917 | * | |
918 | * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May | |
919 | * be called in IRQ context. | |
af9b897e AC |
920 | * |
921 | * Locking: takes tty_ldisc_lock | |
1da177e4 | 922 | */ |
37bdfb07 | 923 | |
1da177e4 LT |
924 | void tty_ldisc_deref(struct tty_ldisc *ld) |
925 | { | |
926 | unsigned long flags; | |
927 | ||
56ee4827 | 928 | BUG_ON(ld == NULL); |
37bdfb07 | 929 | |
1da177e4 | 930 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
37bdfb07 | 931 | if (ld->refcount == 0) |
1da177e4 LT |
932 | printk(KERN_ERR "tty_ldisc_deref: no references.\n"); |
933 | else | |
934 | ld->refcount--; | |
37bdfb07 | 935 | if (ld->refcount == 0) |
1da177e4 LT |
936 | wake_up(&tty_ldisc_wait); |
937 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
938 | } | |
939 | ||
940 | EXPORT_SYMBOL_GPL(tty_ldisc_deref); | |
941 | ||
942 | /** | |
943 | * tty_ldisc_enable - allow ldisc use | |
944 | * @tty: terminal to activate ldisc on | |
945 | * | |
946 | * Set the TTY_LDISC flag when the line discipline can be called | |
3a4fa0a2 | 947 | * again. Do necessary wakeups for existing sleepers. |
1da177e4 LT |
948 | * |
949 | * Note: nobody should set this bit except via this function. Clearing | |
950 | * directly is allowed. | |
951 | */ | |
952 | ||
953 | static void tty_ldisc_enable(struct tty_struct *tty) | |
954 | { | |
955 | set_bit(TTY_LDISC, &tty->flags); | |
956 | wake_up(&tty_ldisc_wait); | |
957 | } | |
37bdfb07 | 958 | |
1da177e4 LT |
959 | /** |
960 | * tty_set_ldisc - set line discipline | |
961 | * @tty: the terminal to set | |
962 | * @ldisc: the line discipline | |
963 | * | |
964 | * Set the discipline of a tty line. Must be called from a process | |
965 | * context. | |
af9b897e AC |
966 | * |
967 | * Locking: takes tty_ldisc_lock. | |
24ec839c | 968 | * called functions take termios_mutex |
1da177e4 | 969 | */ |
37bdfb07 | 970 | |
1da177e4 LT |
971 | static int tty_set_ldisc(struct tty_struct *tty, int ldisc) |
972 | { | |
ff55fe20 JB |
973 | int retval = 0; |
974 | struct tty_ldisc o_ldisc; | |
1da177e4 LT |
975 | char buf[64]; |
976 | int work; | |
977 | unsigned long flags; | |
978 | struct tty_ldisc *ld; | |
ff55fe20 | 979 | struct tty_struct *o_tty; |
1da177e4 LT |
980 | |
981 | if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) | |
982 | return -EINVAL; | |
983 | ||
984 | restart: | |
985 | ||
1da177e4 LT |
986 | ld = tty_ldisc_get(ldisc); |
987 | /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ | |
988 | /* Cyrus Durgin <cider@speakeasy.org> */ | |
989 | if (ld == NULL) { | |
990 | request_module("tty-ldisc-%d", ldisc); | |
991 | ld = tty_ldisc_get(ldisc); | |
992 | } | |
993 | if (ld == NULL) | |
994 | return -EINVAL; | |
995 | ||
33f0f88f AC |
996 | /* |
997 | * Problem: What do we do if this blocks ? | |
998 | */ | |
999 | ||
1da177e4 LT |
1000 | tty_wait_until_sent(tty, 0); |
1001 | ||
ff55fe20 JB |
1002 | if (tty->ldisc.num == ldisc) { |
1003 | tty_ldisc_put(ldisc); | |
1004 | return 0; | |
1005 | } | |
1006 | ||
ae030e43 PF |
1007 | /* |
1008 | * No more input please, we are switching. The new ldisc | |
1009 | * will update this value in the ldisc open function | |
1010 | */ | |
1011 | ||
1012 | tty->receive_room = 0; | |
1013 | ||
ff55fe20 JB |
1014 | o_ldisc = tty->ldisc; |
1015 | o_tty = tty->link; | |
1016 | ||
1da177e4 LT |
1017 | /* |
1018 | * Make sure we don't change while someone holds a | |
1019 | * reference to the line discipline. The TTY_LDISC bit | |
1020 | * prevents anyone taking a reference once it is clear. | |
1021 | * We need the lock to avoid racing reference takers. | |
1022 | */ | |
ff55fe20 | 1023 | |
1da177e4 | 1024 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
ff55fe20 | 1025 | if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { |
37bdfb07 | 1026 | if (tty->ldisc.refcount) { |
ff55fe20 JB |
1027 | /* Free the new ldisc we grabbed. Must drop the lock |
1028 | first. */ | |
1029 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
1030 | tty_ldisc_put(ldisc); | |
1031 | /* | |
1032 | * There are several reasons we may be busy, including | |
1033 | * random momentary I/O traffic. We must therefore | |
1034 | * retry. We could distinguish between blocking ops | |
37bdfb07 AC |
1035 | * and retries if we made tty_ldisc_wait() smarter. |
1036 | * That is up for discussion. | |
ff55fe20 JB |
1037 | */ |
1038 | if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) | |
1039 | return -ERESTARTSYS; | |
1040 | goto restart; | |
1041 | } | |
37bdfb07 | 1042 | if (o_tty && o_tty->ldisc.refcount) { |
ff55fe20 JB |
1043 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
1044 | tty_ldisc_put(ldisc); | |
1045 | if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) | |
1046 | return -ERESTARTSYS; | |
1047 | goto restart; | |
1048 | } | |
1049 | } | |
37bdfb07 AC |
1050 | /* |
1051 | * If the TTY_LDISC bit is set, then we are racing against | |
1052 | * another ldisc change | |
1053 | */ | |
ff55fe20 | 1054 | if (!test_bit(TTY_LDISC, &tty->flags)) { |
1da177e4 LT |
1055 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
1056 | tty_ldisc_put(ldisc); | |
ff55fe20 JB |
1057 | ld = tty_ldisc_ref_wait(tty); |
1058 | tty_ldisc_deref(ld); | |
1da177e4 LT |
1059 | goto restart; |
1060 | } | |
ff55fe20 JB |
1061 | |
1062 | clear_bit(TTY_LDISC, &tty->flags); | |
817d6d3b | 1063 | if (o_tty) |
ff55fe20 | 1064 | clear_bit(TTY_LDISC, &o_tty->flags); |
1da177e4 | 1065 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
ff55fe20 | 1066 | |
1da177e4 LT |
1067 | /* |
1068 | * From this point on we know nobody has an ldisc | |
1069 | * usage reference, nor can they obtain one until | |
1070 | * we say so later on. | |
1071 | */ | |
ff55fe20 | 1072 | |
33f0f88f | 1073 | work = cancel_delayed_work(&tty->buf.work); |
1da177e4 | 1074 | /* |
33f0f88f | 1075 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 | 1076 | */ |
1da177e4 LT |
1077 | flush_scheduled_work(); |
1078 | /* Shutdown the current discipline. */ | |
1079 | if (tty->ldisc.close) | |
1080 | (tty->ldisc.close)(tty); | |
1081 | ||
1082 | /* Now set up the new line discipline. */ | |
1083 | tty_ldisc_assign(tty, ld); | |
1084 | tty_set_termios_ldisc(tty, ldisc); | |
1085 | if (tty->ldisc.open) | |
1086 | retval = (tty->ldisc.open)(tty); | |
1087 | if (retval < 0) { | |
1088 | tty_ldisc_put(ldisc); | |
1089 | /* There is an outstanding reference here so this is safe */ | |
1090 | tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); | |
1091 | tty_set_termios_ldisc(tty, tty->ldisc.num); | |
1092 | if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { | |
1093 | tty_ldisc_put(o_ldisc.num); | |
1094 | /* This driver is always present */ | |
1095 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
1096 | tty_set_termios_ldisc(tty, N_TTY); | |
1097 | if (tty->ldisc.open) { | |
1098 | int r = tty->ldisc.open(tty); | |
1099 | ||
1100 | if (r < 0) | |
1101 | panic("Couldn't open N_TTY ldisc for " | |
1102 | "%s --- error %d.", | |
1103 | tty_name(tty, buf), r); | |
1104 | } | |
1105 | } | |
1106 | } | |
1107 | /* At this point we hold a reference to the new ldisc and a | |
1108 | a reference to the old ldisc. If we ended up flipping back | |
1109 | to the existing ldisc we have two references to it */ | |
37bdfb07 | 1110 | |
1da177e4 LT |
1111 | if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) |
1112 | tty->driver->set_ldisc(tty); | |
37bdfb07 | 1113 | |
1da177e4 | 1114 | tty_ldisc_put(o_ldisc.num); |
37bdfb07 | 1115 | |
1da177e4 LT |
1116 | /* |
1117 | * Allow ldisc referencing to occur as soon as the driver | |
1118 | * ldisc callback completes. | |
1119 | */ | |
37bdfb07 | 1120 | |
1da177e4 | 1121 | tty_ldisc_enable(tty); |
ff55fe20 JB |
1122 | if (o_tty) |
1123 | tty_ldisc_enable(o_tty); | |
37bdfb07 | 1124 | |
1da177e4 LT |
1125 | /* Restart it in case no characters kick it off. Safe if |
1126 | already running */ | |
ff55fe20 | 1127 | if (work) |
33f0f88f | 1128 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
1129 | return retval; |
1130 | } | |
1131 | ||
af9b897e AC |
1132 | /** |
1133 | * get_tty_driver - find device of a tty | |
1134 | * @dev_t: device identifier | |
1135 | * @index: returns the index of the tty | |
1136 | * | |
1137 | * This routine returns a tty driver structure, given a device number | |
1138 | * and also passes back the index number. | |
1139 | * | |
1140 | * Locking: caller must hold tty_mutex | |
1da177e4 | 1141 | */ |
af9b897e | 1142 | |
1da177e4 LT |
1143 | static struct tty_driver *get_tty_driver(dev_t device, int *index) |
1144 | { | |
1145 | struct tty_driver *p; | |
1146 | ||
1147 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1148 | dev_t base = MKDEV(p->major, p->minor_start); | |
1149 | if (device < base || device >= base + p->num) | |
1150 | continue; | |
1151 | *index = device - base; | |
1152 | return p; | |
1153 | } | |
1154 | return NULL; | |
1155 | } | |
1156 | ||
f2d937f3 JW |
1157 | #ifdef CONFIG_CONSOLE_POLL |
1158 | ||
1159 | /** | |
1160 | * tty_find_polling_driver - find device of a polled tty | |
1161 | * @name: name string to match | |
1162 | * @line: pointer to resulting tty line nr | |
1163 | * | |
1164 | * This routine returns a tty driver structure, given a name | |
1165 | * and the condition that the tty driver is capable of polled | |
1166 | * operation. | |
1167 | */ | |
1168 | struct tty_driver *tty_find_polling_driver(char *name, int *line) | |
1169 | { | |
1170 | struct tty_driver *p, *res = NULL; | |
1171 | int tty_line = 0; | |
1172 | char *str; | |
1173 | ||
1174 | mutex_lock(&tty_mutex); | |
1175 | /* Search through the tty devices to look for a match */ | |
1176 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1177 | str = name + strlen(p->name); | |
1178 | tty_line = simple_strtoul(str, &str, 10); | |
1179 | if (*str == ',') | |
1180 | str++; | |
1181 | if (*str == '\0') | |
8da56309 | 1182 | str = NULL; |
f2d937f3 JW |
1183 | |
1184 | if (tty_line >= 0 && tty_line <= p->num && p->poll_init && | |
1185 | !p->poll_init(p, tty_line, str)) { | |
1186 | ||
1187 | res = p; | |
1188 | *line = tty_line; | |
1189 | break; | |
1190 | } | |
1191 | } | |
1192 | mutex_unlock(&tty_mutex); | |
1193 | ||
1194 | return res; | |
1195 | } | |
1196 | EXPORT_SYMBOL_GPL(tty_find_polling_driver); | |
1197 | #endif | |
1198 | ||
af9b897e AC |
1199 | /** |
1200 | * tty_check_change - check for POSIX terminal changes | |
1201 | * @tty: tty to check | |
1202 | * | |
1203 | * If we try to write to, or set the state of, a terminal and we're | |
1204 | * not in the foreground, send a SIGTTOU. If the signal is blocked or | |
1205 | * ignored, go ahead and perform the operation. (POSIX 7.2) | |
1206 | * | |
04f378b1 | 1207 | * Locking: none - FIXME: review this |
1da177e4 | 1208 | */ |
af9b897e | 1209 | |
37bdfb07 | 1210 | int tty_check_change(struct tty_struct *tty) |
1da177e4 LT |
1211 | { |
1212 | if (current->signal->tty != tty) | |
1213 | return 0; | |
ab521dc0 EB |
1214 | if (!tty->pgrp) { |
1215 | printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n"); | |
1da177e4 LT |
1216 | return 0; |
1217 | } | |
ab521dc0 | 1218 | if (task_pgrp(current) == tty->pgrp) |
1da177e4 LT |
1219 | return 0; |
1220 | if (is_ignored(SIGTTOU)) | |
1221 | return 0; | |
3e7cd6c4 | 1222 | if (is_current_pgrp_orphaned()) |
1da177e4 | 1223 | return -EIO; |
040b6362 ON |
1224 | kill_pgrp(task_pgrp(current), SIGTTOU, 1); |
1225 | set_thread_flag(TIF_SIGPENDING); | |
1da177e4 LT |
1226 | return -ERESTARTSYS; |
1227 | } | |
1228 | ||
1229 | EXPORT_SYMBOL(tty_check_change); | |
1230 | ||
37bdfb07 | 1231 | static ssize_t hung_up_tty_read(struct file *file, char __user *buf, |
1da177e4 LT |
1232 | size_t count, loff_t *ppos) |
1233 | { | |
1234 | return 0; | |
1235 | } | |
1236 | ||
37bdfb07 | 1237 | static ssize_t hung_up_tty_write(struct file *file, const char __user *buf, |
1da177e4 LT |
1238 | size_t count, loff_t *ppos) |
1239 | { | |
1240 | return -EIO; | |
1241 | } | |
1242 | ||
1243 | /* No kernel lock held - none needed ;) */ | |
37bdfb07 | 1244 | static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait) |
1da177e4 LT |
1245 | { |
1246 | return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; | |
1247 | } | |
1248 | ||
04f378b1 AC |
1249 | static long hung_up_tty_ioctl(struct file *file, unsigned int cmd, |
1250 | unsigned long arg) | |
38ad2ed0 PF |
1251 | { |
1252 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1253 | } | |
1254 | ||
37bdfb07 | 1255 | static long hung_up_tty_compat_ioctl(struct file *file, |
38ad2ed0 | 1256 | unsigned int cmd, unsigned long arg) |
1da177e4 LT |
1257 | { |
1258 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1259 | } | |
1260 | ||
62322d25 | 1261 | static const struct file_operations tty_fops = { |
1da177e4 LT |
1262 | .llseek = no_llseek, |
1263 | .read = tty_read, | |
1264 | .write = tty_write, | |
1265 | .poll = tty_poll, | |
04f378b1 | 1266 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1267 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1268 | .open = tty_open, |
1269 | .release = tty_release, | |
1270 | .fasync = tty_fasync, | |
1271 | }; | |
1272 | ||
1273 | #ifdef CONFIG_UNIX98_PTYS | |
62322d25 | 1274 | static const struct file_operations ptmx_fops = { |
1da177e4 LT |
1275 | .llseek = no_llseek, |
1276 | .read = tty_read, | |
1277 | .write = tty_write, | |
1278 | .poll = tty_poll, | |
04f378b1 | 1279 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1280 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1281 | .open = ptmx_open, |
1282 | .release = tty_release, | |
1283 | .fasync = tty_fasync, | |
1284 | }; | |
1285 | #endif | |
1286 | ||
62322d25 | 1287 | static const struct file_operations console_fops = { |
1da177e4 LT |
1288 | .llseek = no_llseek, |
1289 | .read = tty_read, | |
1290 | .write = redirected_tty_write, | |
1291 | .poll = tty_poll, | |
04f378b1 | 1292 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1293 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1294 | .open = tty_open, |
1295 | .release = tty_release, | |
1296 | .fasync = tty_fasync, | |
1297 | }; | |
1298 | ||
62322d25 | 1299 | static const struct file_operations hung_up_tty_fops = { |
1da177e4 LT |
1300 | .llseek = no_llseek, |
1301 | .read = hung_up_tty_read, | |
1302 | .write = hung_up_tty_write, | |
1303 | .poll = hung_up_tty_poll, | |
04f378b1 | 1304 | .unlocked_ioctl = hung_up_tty_ioctl, |
38ad2ed0 | 1305 | .compat_ioctl = hung_up_tty_compat_ioctl, |
1da177e4 LT |
1306 | .release = tty_release, |
1307 | }; | |
1308 | ||
1309 | static DEFINE_SPINLOCK(redirect_lock); | |
1310 | static struct file *redirect; | |
1311 | ||
1312 | /** | |
1313 | * tty_wakeup - request more data | |
1314 | * @tty: terminal | |
1315 | * | |
1316 | * Internal and external helper for wakeups of tty. This function | |
1317 | * informs the line discipline if present that the driver is ready | |
1318 | * to receive more output data. | |
1319 | */ | |
37bdfb07 | 1320 | |
1da177e4 LT |
1321 | void tty_wakeup(struct tty_struct *tty) |
1322 | { | |
1323 | struct tty_ldisc *ld; | |
37bdfb07 | 1324 | |
1da177e4 LT |
1325 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { |
1326 | ld = tty_ldisc_ref(tty); | |
37bdfb07 AC |
1327 | if (ld) { |
1328 | if (ld->write_wakeup) | |
1da177e4 LT |
1329 | ld->write_wakeup(tty); |
1330 | tty_ldisc_deref(ld); | |
1331 | } | |
1332 | } | |
1333 | wake_up_interruptible(&tty->write_wait); | |
1334 | } | |
1335 | ||
1336 | EXPORT_SYMBOL_GPL(tty_wakeup); | |
1337 | ||
1338 | /** | |
1339 | * tty_ldisc_flush - flush line discipline queue | |
1340 | * @tty: tty | |
1341 | * | |
1342 | * Flush the line discipline queue (if any) for this tty. If there | |
1343 | * is no line discipline active this is a no-op. | |
1344 | */ | |
37bdfb07 | 1345 | |
1da177e4 LT |
1346 | void tty_ldisc_flush(struct tty_struct *tty) |
1347 | { | |
1348 | struct tty_ldisc *ld = tty_ldisc_ref(tty); | |
37bdfb07 AC |
1349 | if (ld) { |
1350 | if (ld->flush_buffer) | |
1da177e4 LT |
1351 | ld->flush_buffer(tty); |
1352 | tty_ldisc_deref(ld); | |
1353 | } | |
c5c34d48 | 1354 | tty_buffer_flush(tty); |
1da177e4 LT |
1355 | } |
1356 | ||
1357 | EXPORT_SYMBOL_GPL(tty_ldisc_flush); | |
edc6afc5 AC |
1358 | |
1359 | /** | |
1360 | * tty_reset_termios - reset terminal state | |
1361 | * @tty: tty to reset | |
1362 | * | |
1363 | * Restore a terminal to the driver default state | |
1364 | */ | |
1365 | ||
1366 | static void tty_reset_termios(struct tty_struct *tty) | |
1367 | { | |
1368 | mutex_lock(&tty->termios_mutex); | |
1369 | *tty->termios = tty->driver->init_termios; | |
1370 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
1371 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1372 | mutex_unlock(&tty->termios_mutex); | |
1373 | } | |
37bdfb07 | 1374 | |
af9b897e AC |
1375 | /** |
1376 | * do_tty_hangup - actual handler for hangup events | |
65f27f38 | 1377 | * @work: tty device |
af9b897e AC |
1378 | * |
1379 | * This can be called by the "eventd" kernel thread. That is process | |
1380 | * synchronous but doesn't hold any locks, so we need to make sure we | |
1381 | * have the appropriate locks for what we're doing. | |
1382 | * | |
1383 | * The hangup event clears any pending redirections onto the hung up | |
1384 | * device. It ensures future writes will error and it does the needed | |
1385 | * line discipline hangup and signal delivery. The tty object itself | |
1386 | * remains intact. | |
1387 | * | |
1388 | * Locking: | |
1389 | * BKL | |
24ec839c PZ |
1390 | * redirect lock for undoing redirection |
1391 | * file list lock for manipulating list of ttys | |
1392 | * tty_ldisc_lock from called functions | |
1393 | * termios_mutex resetting termios data | |
1394 | * tasklist_lock to walk task list for hangup event | |
1395 | * ->siglock to protect ->signal/->sighand | |
1da177e4 | 1396 | */ |
65f27f38 | 1397 | static void do_tty_hangup(struct work_struct *work) |
1da177e4 | 1398 | { |
65f27f38 DH |
1399 | struct tty_struct *tty = |
1400 | container_of(work, struct tty_struct, hangup_work); | |
37bdfb07 | 1401 | struct file *cons_filp = NULL; |
1da177e4 LT |
1402 | struct file *filp, *f = NULL; |
1403 | struct task_struct *p; | |
1404 | struct tty_ldisc *ld; | |
1405 | int closecount = 0, n; | |
1406 | ||
1407 | if (!tty) | |
1408 | return; | |
1409 | ||
1410 | /* inuse_filps is protected by the single kernel lock */ | |
1411 | lock_kernel(); | |
1412 | ||
1413 | spin_lock(&redirect_lock); | |
1414 | if (redirect && redirect->private_data == tty) { | |
1415 | f = redirect; | |
1416 | redirect = NULL; | |
1417 | } | |
1418 | spin_unlock(&redirect_lock); | |
37bdfb07 | 1419 | |
1da177e4 LT |
1420 | check_tty_count(tty, "do_tty_hangup"); |
1421 | file_list_lock(); | |
1422 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ | |
2f512016 | 1423 | list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { |
1da177e4 LT |
1424 | if (filp->f_op->write == redirected_tty_write) |
1425 | cons_filp = filp; | |
1426 | if (filp->f_op->write != tty_write) | |
1427 | continue; | |
1428 | closecount++; | |
1429 | tty_fasync(-1, filp, 0); /* can't block */ | |
1430 | filp->f_op = &hung_up_tty_fops; | |
1431 | } | |
1432 | file_list_unlock(); | |
37bdfb07 AC |
1433 | /* |
1434 | * FIXME! What are the locking issues here? This may me overdoing | |
1435 | * things... This question is especially important now that we've | |
1436 | * removed the irqlock. | |
1437 | */ | |
1da177e4 | 1438 | ld = tty_ldisc_ref(tty); |
37bdfb07 AC |
1439 | if (ld != NULL) { |
1440 | /* We may have no line discipline at this point */ | |
1da177e4 LT |
1441 | if (ld->flush_buffer) |
1442 | ld->flush_buffer(tty); | |
1443 | if (tty->driver->flush_buffer) | |
1444 | tty->driver->flush_buffer(tty); | |
1445 | if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && | |
1446 | ld->write_wakeup) | |
1447 | ld->write_wakeup(tty); | |
1448 | if (ld->hangup) | |
1449 | ld->hangup(tty); | |
1450 | } | |
37bdfb07 AC |
1451 | /* |
1452 | * FIXME: Once we trust the LDISC code better we can wait here for | |
1453 | * ldisc completion and fix the driver call race | |
1454 | */ | |
1da177e4 LT |
1455 | wake_up_interruptible(&tty->write_wait); |
1456 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1457 | /* |
1458 | * Shutdown the current line discipline, and reset it to | |
1459 | * N_TTY. | |
1460 | */ | |
1461 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
edc6afc5 | 1462 | tty_reset_termios(tty); |
1da177e4 LT |
1463 | /* Defer ldisc switch */ |
1464 | /* tty_deferred_ldisc_switch(N_TTY); | |
37bdfb07 | 1465 | |
1da177e4 LT |
1466 | This should get done automatically when the port closes and |
1467 | tty_release is called */ | |
37bdfb07 | 1468 | |
1da177e4 | 1469 | read_lock(&tasklist_lock); |
ab521dc0 EB |
1470 | if (tty->session) { |
1471 | do_each_pid_task(tty->session, PIDTYPE_SID, p) { | |
24ec839c | 1472 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
1473 | if (p->signal->tty == tty) |
1474 | p->signal->tty = NULL; | |
24ec839c PZ |
1475 | if (!p->signal->leader) { |
1476 | spin_unlock_irq(&p->sighand->siglock); | |
1da177e4 | 1477 | continue; |
24ec839c PZ |
1478 | } |
1479 | __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); | |
1480 | __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); | |
ab521dc0 EB |
1481 | put_pid(p->signal->tty_old_pgrp); /* A noop */ |
1482 | if (tty->pgrp) | |
1483 | p->signal->tty_old_pgrp = get_pid(tty->pgrp); | |
24ec839c | 1484 | spin_unlock_irq(&p->sighand->siglock); |
ab521dc0 | 1485 | } while_each_pid_task(tty->session, PIDTYPE_SID, p); |
1da177e4 LT |
1486 | } |
1487 | read_unlock(&tasklist_lock); | |
1488 | ||
1489 | tty->flags = 0; | |
d9c1e9a8 EB |
1490 | put_pid(tty->session); |
1491 | put_pid(tty->pgrp); | |
ab521dc0 EB |
1492 | tty->session = NULL; |
1493 | tty->pgrp = NULL; | |
1da177e4 LT |
1494 | tty->ctrl_status = 0; |
1495 | /* | |
37bdfb07 AC |
1496 | * If one of the devices matches a console pointer, we |
1497 | * cannot just call hangup() because that will cause | |
1498 | * tty->count and state->count to go out of sync. | |
1499 | * So we just call close() the right number of times. | |
1da177e4 LT |
1500 | */ |
1501 | if (cons_filp) { | |
1502 | if (tty->driver->close) | |
1503 | for (n = 0; n < closecount; n++) | |
1504 | tty->driver->close(tty, cons_filp); | |
1505 | } else if (tty->driver->hangup) | |
1506 | (tty->driver->hangup)(tty); | |
37bdfb07 AC |
1507 | /* |
1508 | * We don't want to have driver/ldisc interactions beyond | |
1509 | * the ones we did here. The driver layer expects no | |
1510 | * calls after ->hangup() from the ldisc side. However we | |
1511 | * can't yet guarantee all that. | |
1512 | */ | |
1da177e4 LT |
1513 | set_bit(TTY_HUPPED, &tty->flags); |
1514 | if (ld) { | |
1515 | tty_ldisc_enable(tty); | |
1516 | tty_ldisc_deref(ld); | |
1517 | } | |
1518 | unlock_kernel(); | |
1519 | if (f) | |
1520 | fput(f); | |
1521 | } | |
1522 | ||
af9b897e AC |
1523 | /** |
1524 | * tty_hangup - trigger a hangup event | |
1525 | * @tty: tty to hangup | |
1526 | * | |
1527 | * A carrier loss (virtual or otherwise) has occurred on this like | |
1528 | * schedule a hangup sequence to run after this event. | |
1529 | */ | |
1530 | ||
37bdfb07 | 1531 | void tty_hangup(struct tty_struct *tty) |
1da177e4 LT |
1532 | { |
1533 | #ifdef TTY_DEBUG_HANGUP | |
1534 | char buf[64]; | |
1da177e4 LT |
1535 | printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); |
1536 | #endif | |
1537 | schedule_work(&tty->hangup_work); | |
1538 | } | |
1539 | ||
1540 | EXPORT_SYMBOL(tty_hangup); | |
1541 | ||
af9b897e AC |
1542 | /** |
1543 | * tty_vhangup - process vhangup | |
1544 | * @tty: tty to hangup | |
1545 | * | |
1546 | * The user has asked via system call for the terminal to be hung up. | |
1547 | * We do this synchronously so that when the syscall returns the process | |
3a4fa0a2 | 1548 | * is complete. That guarantee is necessary for security reasons. |
af9b897e AC |
1549 | */ |
1550 | ||
37bdfb07 | 1551 | void tty_vhangup(struct tty_struct *tty) |
1da177e4 LT |
1552 | { |
1553 | #ifdef TTY_DEBUG_HANGUP | |
1554 | char buf[64]; | |
1555 | ||
1556 | printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); | |
1557 | #endif | |
65f27f38 | 1558 | do_tty_hangup(&tty->hangup_work); |
1da177e4 | 1559 | } |
37bdfb07 | 1560 | |
1da177e4 LT |
1561 | EXPORT_SYMBOL(tty_vhangup); |
1562 | ||
af9b897e AC |
1563 | /** |
1564 | * tty_hung_up_p - was tty hung up | |
1565 | * @filp: file pointer of tty | |
1566 | * | |
1567 | * Return true if the tty has been subject to a vhangup or a carrier | |
1568 | * loss | |
1569 | */ | |
1570 | ||
37bdfb07 | 1571 | int tty_hung_up_p(struct file *filp) |
1da177e4 LT |
1572 | { |
1573 | return (filp->f_op == &hung_up_tty_fops); | |
1574 | } | |
1575 | ||
1576 | EXPORT_SYMBOL(tty_hung_up_p); | |
1577 | ||
522ed776 | 1578 | /** |
37bdfb07 AC |
1579 | * is_tty - checker whether file is a TTY |
1580 | * @filp: file handle that may be a tty | |
1581 | * | |
1582 | * Check if the file handle is a tty handle. | |
522ed776 | 1583 | */ |
37bdfb07 | 1584 | |
522ed776 MT |
1585 | int is_tty(struct file *filp) |
1586 | { | |
1587 | return filp->f_op->read == tty_read | |
1588 | || filp->f_op->read == hung_up_tty_read; | |
1589 | } | |
1590 | ||
ab521dc0 | 1591 | static void session_clear_tty(struct pid *session) |
24ec839c PZ |
1592 | { |
1593 | struct task_struct *p; | |
ab521dc0 | 1594 | do_each_pid_task(session, PIDTYPE_SID, p) { |
24ec839c | 1595 | proc_clear_tty(p); |
ab521dc0 | 1596 | } while_each_pid_task(session, PIDTYPE_SID, p); |
24ec839c PZ |
1597 | } |
1598 | ||
af9b897e AC |
1599 | /** |
1600 | * disassociate_ctty - disconnect controlling tty | |
1601 | * @on_exit: true if exiting so need to "hang up" the session | |
1da177e4 | 1602 | * |
af9b897e AC |
1603 | * This function is typically called only by the session leader, when |
1604 | * it wants to disassociate itself from its controlling tty. | |
1605 | * | |
1606 | * It performs the following functions: | |
1da177e4 LT |
1607 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
1608 | * (2) Clears the tty from being controlling the session | |
1609 | * (3) Clears the controlling tty for all processes in the | |
1610 | * session group. | |
1611 | * | |
af9b897e AC |
1612 | * The argument on_exit is set to 1 if called when a process is |
1613 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. | |
1614 | * | |
24ec839c | 1615 | * Locking: |
af9b897e | 1616 | * BKL is taken for hysterical raisins |
24ec839c PZ |
1617 | * tty_mutex is taken to protect tty |
1618 | * ->siglock is taken to protect ->signal/->sighand | |
1619 | * tasklist_lock is taken to walk process list for sessions | |
1620 | * ->siglock is taken to protect ->signal/->sighand | |
1da177e4 | 1621 | */ |
af9b897e | 1622 | |
1da177e4 LT |
1623 | void disassociate_ctty(int on_exit) |
1624 | { | |
1625 | struct tty_struct *tty; | |
ab521dc0 | 1626 | struct pid *tty_pgrp = NULL; |
1da177e4 | 1627 | |
1da177e4 | 1628 | |
70522e12 | 1629 | mutex_lock(&tty_mutex); |
24ec839c | 1630 | tty = get_current_tty(); |
1da177e4 | 1631 | if (tty) { |
ab521dc0 | 1632 | tty_pgrp = get_pid(tty->pgrp); |
70522e12 | 1633 | mutex_unlock(&tty_mutex); |
04f378b1 | 1634 | lock_kernel(); |
24ec839c | 1635 | /* XXX: here we race, there is nothing protecting tty */ |
1da177e4 LT |
1636 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
1637 | tty_vhangup(tty); | |
04f378b1 | 1638 | unlock_kernel(); |
680a9671 | 1639 | } else if (on_exit) { |
ab521dc0 | 1640 | struct pid *old_pgrp; |
680a9671 EB |
1641 | spin_lock_irq(¤t->sighand->siglock); |
1642 | old_pgrp = current->signal->tty_old_pgrp; | |
ab521dc0 | 1643 | current->signal->tty_old_pgrp = NULL; |
680a9671 | 1644 | spin_unlock_irq(¤t->sighand->siglock); |
24ec839c | 1645 | if (old_pgrp) { |
ab521dc0 EB |
1646 | kill_pgrp(old_pgrp, SIGHUP, on_exit); |
1647 | kill_pgrp(old_pgrp, SIGCONT, on_exit); | |
1648 | put_pid(old_pgrp); | |
1da177e4 | 1649 | } |
70522e12 | 1650 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
1651 | return; |
1652 | } | |
ab521dc0 EB |
1653 | if (tty_pgrp) { |
1654 | kill_pgrp(tty_pgrp, SIGHUP, on_exit); | |
1da177e4 | 1655 | if (!on_exit) |
ab521dc0 EB |
1656 | kill_pgrp(tty_pgrp, SIGCONT, on_exit); |
1657 | put_pid(tty_pgrp); | |
1da177e4 LT |
1658 | } |
1659 | ||
24ec839c | 1660 | spin_lock_irq(¤t->sighand->siglock); |
2a65f1d9 | 1661 | put_pid(current->signal->tty_old_pgrp); |
23cac8de | 1662 | current->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
1663 | spin_unlock_irq(¤t->sighand->siglock); |
1664 | ||
1665 | mutex_lock(&tty_mutex); | |
1666 | /* It is possible that do_tty_hangup has free'd this tty */ | |
1667 | tty = get_current_tty(); | |
1668 | if (tty) { | |
ab521dc0 EB |
1669 | put_pid(tty->session); |
1670 | put_pid(tty->pgrp); | |
1671 | tty->session = NULL; | |
1672 | tty->pgrp = NULL; | |
24ec839c PZ |
1673 | } else { |
1674 | #ifdef TTY_DEBUG_HANGUP | |
1675 | printk(KERN_DEBUG "error attempted to write to tty [0x%p]" | |
1676 | " = NULL", tty); | |
1677 | #endif | |
1678 | } | |
1679 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
1680 | |
1681 | /* Now clear signal->tty under the lock */ | |
1682 | read_lock(&tasklist_lock); | |
ab521dc0 | 1683 | session_clear_tty(task_session(current)); |
1da177e4 | 1684 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1685 | } |
1686 | ||
98a27ba4 EB |
1687 | /** |
1688 | * | |
1689 | * no_tty - Ensure the current process does not have a controlling tty | |
1690 | */ | |
1691 | void no_tty(void) | |
1692 | { | |
1693 | struct task_struct *tsk = current; | |
04f378b1 | 1694 | lock_kernel(); |
98a27ba4 EB |
1695 | if (tsk->signal->leader) |
1696 | disassociate_ctty(0); | |
04f378b1 | 1697 | unlock_kernel(); |
98a27ba4 EB |
1698 | proc_clear_tty(tsk); |
1699 | } | |
1700 | ||
af9b897e AC |
1701 | |
1702 | /** | |
beb7dd86 | 1703 | * stop_tty - propagate flow control |
af9b897e AC |
1704 | * @tty: tty to stop |
1705 | * | |
1706 | * Perform flow control to the driver. For PTY/TTY pairs we | |
beb7dd86 | 1707 | * must also propagate the TIOCKPKT status. May be called |
af9b897e AC |
1708 | * on an already stopped device and will not re-call the driver |
1709 | * method. | |
1710 | * | |
1711 | * This functionality is used by both the line disciplines for | |
1712 | * halting incoming flow and by the driver. It may therefore be | |
1713 | * called from any context, may be under the tty atomic_write_lock | |
1714 | * but not always. | |
1715 | * | |
1716 | * Locking: | |
04f378b1 | 1717 | * Uses the tty control lock internally |
af9b897e AC |
1718 | */ |
1719 | ||
1da177e4 LT |
1720 | void stop_tty(struct tty_struct *tty) |
1721 | { | |
04f378b1 AC |
1722 | unsigned long flags; |
1723 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
1724 | if (tty->stopped) { | |
1725 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
1da177e4 | 1726 | return; |
04f378b1 | 1727 | } |
1da177e4 LT |
1728 | tty->stopped = 1; |
1729 | if (tty->link && tty->link->packet) { | |
1730 | tty->ctrl_status &= ~TIOCPKT_START; | |
1731 | tty->ctrl_status |= TIOCPKT_STOP; | |
1732 | wake_up_interruptible(&tty->link->read_wait); | |
1733 | } | |
04f378b1 | 1734 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
1735 | if (tty->driver->stop) |
1736 | (tty->driver->stop)(tty); | |
1737 | } | |
1738 | ||
1739 | EXPORT_SYMBOL(stop_tty); | |
1740 | ||
af9b897e | 1741 | /** |
beb7dd86 | 1742 | * start_tty - propagate flow control |
af9b897e AC |
1743 | * @tty: tty to start |
1744 | * | |
1745 | * Start a tty that has been stopped if at all possible. Perform | |
3a4fa0a2 | 1746 | * any necessary wakeups and propagate the TIOCPKT status. If this |
af9b897e AC |
1747 | * is the tty was previous stopped and is being started then the |
1748 | * driver start method is invoked and the line discipline woken. | |
1749 | * | |
1750 | * Locking: | |
04f378b1 | 1751 | * ctrl_lock |
af9b897e AC |
1752 | */ |
1753 | ||
1da177e4 LT |
1754 | void start_tty(struct tty_struct *tty) |
1755 | { | |
04f378b1 AC |
1756 | unsigned long flags; |
1757 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
1758 | if (!tty->stopped || tty->flow_stopped) { | |
1759 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
1da177e4 | 1760 | return; |
04f378b1 | 1761 | } |
1da177e4 LT |
1762 | tty->stopped = 0; |
1763 | if (tty->link && tty->link->packet) { | |
1764 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
1765 | tty->ctrl_status |= TIOCPKT_START; | |
1766 | wake_up_interruptible(&tty->link->read_wait); | |
1767 | } | |
04f378b1 | 1768 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1da177e4 LT |
1769 | if (tty->driver->start) |
1770 | (tty->driver->start)(tty); | |
1da177e4 LT |
1771 | /* If we have a running line discipline it may need kicking */ |
1772 | tty_wakeup(tty); | |
1da177e4 LT |
1773 | } |
1774 | ||
1775 | EXPORT_SYMBOL(start_tty); | |
1776 | ||
af9b897e AC |
1777 | /** |
1778 | * tty_read - read method for tty device files | |
1779 | * @file: pointer to tty file | |
1780 | * @buf: user buffer | |
1781 | * @count: size of user buffer | |
1782 | * @ppos: unused | |
1783 | * | |
1784 | * Perform the read system call function on this terminal device. Checks | |
1785 | * for hung up devices before calling the line discipline method. | |
1786 | * | |
1787 | * Locking: | |
1788 | * Locks the line discipline internally while needed | |
1789 | * For historical reasons the line discipline read method is | |
1790 | * invoked under the BKL. This will go away in time so do not rely on it | |
1791 | * in new code. Multiple read calls may be outstanding in parallel. | |
1792 | */ | |
1793 | ||
37bdfb07 | 1794 | static ssize_t tty_read(struct file *file, char __user *buf, size_t count, |
1da177e4 LT |
1795 | loff_t *ppos) |
1796 | { | |
1797 | int i; | |
37bdfb07 | 1798 | struct tty_struct *tty; |
1da177e4 LT |
1799 | struct inode *inode; |
1800 | struct tty_ldisc *ld; | |
1801 | ||
1802 | tty = (struct tty_struct *)file->private_data; | |
a7113a96 | 1803 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1804 | if (tty_paranoia_check(tty, inode, "tty_read")) |
1805 | return -EIO; | |
1806 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1807 | return -EIO; | |
1808 | ||
1809 | /* We want to wait for the line discipline to sort out in this | |
1810 | situation */ | |
1811 | ld = tty_ldisc_ref_wait(tty); | |
1da177e4 | 1812 | if (ld->read) |
37bdfb07 | 1813 | i = (ld->read)(tty, file, buf, count); |
1da177e4 LT |
1814 | else |
1815 | i = -EIO; | |
1816 | tty_ldisc_deref(ld); | |
1da177e4 LT |
1817 | if (i > 0) |
1818 | inode->i_atime = current_fs_time(inode->i_sb); | |
1819 | return i; | |
1820 | } | |
1821 | ||
9c1729db AC |
1822 | void tty_write_unlock(struct tty_struct *tty) |
1823 | { | |
1824 | mutex_unlock(&tty->atomic_write_lock); | |
1825 | wake_up_interruptible(&tty->write_wait); | |
1826 | } | |
1827 | ||
1828 | int tty_write_lock(struct tty_struct *tty, int ndelay) | |
1829 | { | |
1830 | if (!mutex_trylock(&tty->atomic_write_lock)) { | |
1831 | if (ndelay) | |
1832 | return -EAGAIN; | |
1833 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) | |
1834 | return -ERESTARTSYS; | |
1835 | } | |
1836 | return 0; | |
1837 | } | |
1838 | ||
1da177e4 LT |
1839 | /* |
1840 | * Split writes up in sane blocksizes to avoid | |
1841 | * denial-of-service type attacks | |
1842 | */ | |
1843 | static inline ssize_t do_tty_write( | |
1844 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
1845 | struct tty_struct *tty, | |
1846 | struct file *file, | |
1847 | const char __user *buf, | |
1848 | size_t count) | |
1849 | { | |
9c1729db | 1850 | ssize_t ret, written = 0; |
1da177e4 | 1851 | unsigned int chunk; |
37bdfb07 | 1852 | |
9c1729db AC |
1853 | ret = tty_write_lock(tty, file->f_flags & O_NDELAY); |
1854 | if (ret < 0) | |
1855 | return ret; | |
1da177e4 LT |
1856 | |
1857 | /* | |
1858 | * We chunk up writes into a temporary buffer. This | |
1859 | * simplifies low-level drivers immensely, since they | |
1860 | * don't have locking issues and user mode accesses. | |
1861 | * | |
1862 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
1863 | * big chunk-size.. | |
1864 | * | |
1865 | * The default chunk-size is 2kB, because the NTTY | |
1866 | * layer has problems with bigger chunks. It will | |
1867 | * claim to be able to handle more characters than | |
1868 | * it actually does. | |
af9b897e AC |
1869 | * |
1870 | * FIXME: This can probably go away now except that 64K chunks | |
1871 | * are too likely to fail unless switched to vmalloc... | |
1da177e4 LT |
1872 | */ |
1873 | chunk = 2048; | |
1874 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
1875 | chunk = 65536; | |
1876 | if (count < chunk) | |
1877 | chunk = count; | |
1878 | ||
70522e12 | 1879 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
1da177e4 LT |
1880 | if (tty->write_cnt < chunk) { |
1881 | unsigned char *buf; | |
1882 | ||
1883 | if (chunk < 1024) | |
1884 | chunk = 1024; | |
1885 | ||
1886 | buf = kmalloc(chunk, GFP_KERNEL); | |
1887 | if (!buf) { | |
9c1729db AC |
1888 | ret = -ENOMEM; |
1889 | goto out; | |
1da177e4 LT |
1890 | } |
1891 | kfree(tty->write_buf); | |
1892 | tty->write_cnt = chunk; | |
1893 | tty->write_buf = buf; | |
1894 | } | |
1895 | ||
1896 | /* Do the write .. */ | |
1897 | for (;;) { | |
1898 | size_t size = count; | |
1899 | if (size > chunk) | |
1900 | size = chunk; | |
1901 | ret = -EFAULT; | |
1902 | if (copy_from_user(tty->write_buf, buf, size)) | |
1903 | break; | |
1da177e4 | 1904 | ret = write(tty, file, tty->write_buf, size); |
1da177e4 LT |
1905 | if (ret <= 0) |
1906 | break; | |
1907 | written += ret; | |
1908 | buf += ret; | |
1909 | count -= ret; | |
1910 | if (!count) | |
1911 | break; | |
1912 | ret = -ERESTARTSYS; | |
1913 | if (signal_pending(current)) | |
1914 | break; | |
1915 | cond_resched(); | |
1916 | } | |
1917 | if (written) { | |
a7113a96 | 1918 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1919 | inode->i_mtime = current_fs_time(inode->i_sb); |
1920 | ret = written; | |
1921 | } | |
9c1729db AC |
1922 | out: |
1923 | tty_write_unlock(tty); | |
1da177e4 LT |
1924 | return ret; |
1925 | } | |
1926 | ||
1927 | ||
af9b897e AC |
1928 | /** |
1929 | * tty_write - write method for tty device file | |
1930 | * @file: tty file pointer | |
1931 | * @buf: user data to write | |
1932 | * @count: bytes to write | |
1933 | * @ppos: unused | |
1934 | * | |
1935 | * Write data to a tty device via the line discipline. | |
1936 | * | |
1937 | * Locking: | |
1938 | * Locks the line discipline as required | |
1939 | * Writes to the tty driver are serialized by the atomic_write_lock | |
1940 | * and are then processed in chunks to the device. The line discipline | |
1941 | * write method will not be involked in parallel for each device | |
1942 | * The line discipline write method is called under the big | |
1943 | * kernel lock for historical reasons. New code should not rely on this. | |
1944 | */ | |
1945 | ||
37bdfb07 AC |
1946 | static ssize_t tty_write(struct file *file, const char __user *buf, |
1947 | size_t count, loff_t *ppos) | |
1da177e4 | 1948 | { |
37bdfb07 | 1949 | struct tty_struct *tty; |
a7113a96 | 1950 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1951 | ssize_t ret; |
1952 | struct tty_ldisc *ld; | |
37bdfb07 | 1953 | |
1da177e4 LT |
1954 | tty = (struct tty_struct *)file->private_data; |
1955 | if (tty_paranoia_check(tty, inode, "tty_write")) | |
1956 | return -EIO; | |
37bdfb07 AC |
1957 | if (!tty || !tty->driver->write || |
1958 | (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1959 | return -EIO; | |
1da177e4 | 1960 | |
37bdfb07 | 1961 | ld = tty_ldisc_ref_wait(tty); |
1da177e4 LT |
1962 | if (!ld->write) |
1963 | ret = -EIO; | |
1964 | else | |
1965 | ret = do_tty_write(ld->write, tty, file, buf, count); | |
1966 | tty_ldisc_deref(ld); | |
1967 | return ret; | |
1968 | } | |
1969 | ||
37bdfb07 AC |
1970 | ssize_t redirected_tty_write(struct file *file, const char __user *buf, |
1971 | size_t count, loff_t *ppos) | |
1da177e4 LT |
1972 | { |
1973 | struct file *p = NULL; | |
1974 | ||
1975 | spin_lock(&redirect_lock); | |
1976 | if (redirect) { | |
1977 | get_file(redirect); | |
1978 | p = redirect; | |
1979 | } | |
1980 | spin_unlock(&redirect_lock); | |
1981 | ||
1982 | if (p) { | |
1983 | ssize_t res; | |
1984 | res = vfs_write(p, buf, count, &p->f_pos); | |
1985 | fput(p); | |
1986 | return res; | |
1987 | } | |
1da177e4 LT |
1988 | return tty_write(file, buf, count, ppos); |
1989 | } | |
1990 | ||
1991 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
1992 | ||
af9b897e AC |
1993 | /** |
1994 | * pty_line_name - generate name for a pty | |
1995 | * @driver: the tty driver in use | |
1996 | * @index: the minor number | |
1997 | * @p: output buffer of at least 6 bytes | |
1998 | * | |
1999 | * Generate a name from a driver reference and write it to the output | |
2000 | * buffer. | |
2001 | * | |
2002 | * Locking: None | |
2003 | */ | |
2004 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
2005 | { |
2006 | int i = index + driver->name_base; | |
2007 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
2008 | sprintf(p, "%s%c%x", | |
37bdfb07 AC |
2009 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, |
2010 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1da177e4 LT |
2011 | } |
2012 | ||
af9b897e AC |
2013 | /** |
2014 | * pty_line_name - generate name for a tty | |
2015 | * @driver: the tty driver in use | |
2016 | * @index: the minor number | |
2017 | * @p: output buffer of at least 7 bytes | |
2018 | * | |
2019 | * Generate a name from a driver reference and write it to the output | |
2020 | * buffer. | |
2021 | * | |
2022 | * Locking: None | |
2023 | */ | |
2024 | static void tty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
2025 | { |
2026 | sprintf(p, "%s%d", driver->name, index + driver->name_base); | |
2027 | } | |
2028 | ||
af9b897e AC |
2029 | /** |
2030 | * init_dev - initialise a tty device | |
2031 | * @driver: tty driver we are opening a device on | |
2032 | * @idx: device index | |
2033 | * @tty: returned tty structure | |
2034 | * | |
2035 | * Prepare a tty device. This may not be a "new" clean device but | |
2036 | * could also be an active device. The pty drivers require special | |
2037 | * handling because of this. | |
2038 | * | |
2039 | * Locking: | |
2040 | * The function is called under the tty_mutex, which | |
2041 | * protects us from the tty struct or driver itself going away. | |
2042 | * | |
2043 | * On exit the tty device has the line discipline attached and | |
2044 | * a reference count of 1. If a pair was created for pty/tty use | |
2045 | * and the other was a pty master then it too has a reference count of 1. | |
2046 | * | |
1da177e4 | 2047 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
70522e12 IM |
2048 | * failed open. The new code protects the open with a mutex, so it's |
2049 | * really quite straightforward. The mutex locking can probably be | |
1da177e4 LT |
2050 | * relaxed for the (most common) case of reopening a tty. |
2051 | */ | |
af9b897e | 2052 | |
1da177e4 LT |
2053 | static int init_dev(struct tty_driver *driver, int idx, |
2054 | struct tty_struct **ret_tty) | |
2055 | { | |
2056 | struct tty_struct *tty, *o_tty; | |
edc6afc5 AC |
2057 | struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; |
2058 | struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; | |
af9b897e | 2059 | int retval = 0; |
1da177e4 LT |
2060 | |
2061 | /* check whether we're reopening an existing tty */ | |
2062 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2063 | tty = devpts_get_tty(idx); | |
5a39e8c6 ASRF |
2064 | /* |
2065 | * If we don't have a tty here on a slave open, it's because | |
2066 | * the master already started the close process and there's | |
2067 | * no relation between devpts file and tty anymore. | |
2068 | */ | |
2069 | if (!tty && driver->subtype == PTY_TYPE_SLAVE) { | |
2070 | retval = -EIO; | |
2071 | goto end_init; | |
2072 | } | |
2073 | /* | |
2074 | * It's safe from now on because init_dev() is called with | |
2075 | * tty_mutex held and release_dev() won't change tty->count | |
2076 | * or tty->flags without having to grab tty_mutex | |
2077 | */ | |
1da177e4 LT |
2078 | if (tty && driver->subtype == PTY_TYPE_MASTER) |
2079 | tty = tty->link; | |
2080 | } else { | |
2081 | tty = driver->ttys[idx]; | |
2082 | } | |
2083 | if (tty) goto fast_track; | |
2084 | ||
2085 | /* | |
2086 | * First time open is complex, especially for PTY devices. | |
2087 | * This code guarantees that either everything succeeds and the | |
2088 | * TTY is ready for operation, or else the table slots are vacated | |
37bdfb07 | 2089 | * and the allocated memory released. (Except that the termios |
1da177e4 LT |
2090 | * and locked termios may be retained.) |
2091 | */ | |
2092 | ||
2093 | if (!try_module_get(driver->owner)) { | |
2094 | retval = -ENODEV; | |
2095 | goto end_init; | |
2096 | } | |
2097 | ||
2098 | o_tty = NULL; | |
2099 | tp = o_tp = NULL; | |
2100 | ltp = o_ltp = NULL; | |
2101 | ||
2102 | tty = alloc_tty_struct(); | |
37bdfb07 | 2103 | if (!tty) |
1da177e4 LT |
2104 | goto fail_no_mem; |
2105 | initialize_tty_struct(tty); | |
2106 | tty->driver = driver; | |
2107 | tty->index = idx; | |
2108 | tty_line_name(driver, idx, tty->name); | |
2109 | ||
2110 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2111 | tp_loc = &tty->termios; | |
2112 | ltp_loc = &tty->termios_locked; | |
2113 | } else { | |
2114 | tp_loc = &driver->termios[idx]; | |
2115 | ltp_loc = &driver->termios_locked[idx]; | |
2116 | } | |
2117 | ||
2118 | if (!*tp_loc) { | |
abcb1ff3 | 2119 | tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2120 | if (!tp) |
2121 | goto free_mem_out; | |
2122 | *tp = driver->init_termios; | |
2123 | } | |
2124 | ||
2125 | if (!*ltp_loc) { | |
506eb99a | 2126 | ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2127 | if (!ltp) |
2128 | goto free_mem_out; | |
1da177e4 LT |
2129 | } |
2130 | ||
2131 | if (driver->type == TTY_DRIVER_TYPE_PTY) { | |
2132 | o_tty = alloc_tty_struct(); | |
2133 | if (!o_tty) | |
2134 | goto free_mem_out; | |
2135 | initialize_tty_struct(o_tty); | |
2136 | o_tty->driver = driver->other; | |
2137 | o_tty->index = idx; | |
2138 | tty_line_name(driver->other, idx, o_tty->name); | |
2139 | ||
2140 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2141 | o_tp_loc = &o_tty->termios; | |
2142 | o_ltp_loc = &o_tty->termios_locked; | |
2143 | } else { | |
2144 | o_tp_loc = &driver->other->termios[idx]; | |
2145 | o_ltp_loc = &driver->other->termios_locked[idx]; | |
2146 | } | |
2147 | ||
2148 | if (!*o_tp_loc) { | |
abcb1ff3 | 2149 | o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2150 | if (!o_tp) |
2151 | goto free_mem_out; | |
2152 | *o_tp = driver->other->init_termios; | |
2153 | } | |
2154 | ||
2155 | if (!*o_ltp_loc) { | |
506eb99a | 2156 | o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2157 | if (!o_ltp) |
2158 | goto free_mem_out; | |
1da177e4 LT |
2159 | } |
2160 | ||
2161 | /* | |
2162 | * Everything allocated ... set up the o_tty structure. | |
2163 | */ | |
37bdfb07 | 2164 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) |
1da177e4 | 2165 | driver->other->ttys[idx] = o_tty; |
1da177e4 LT |
2166 | if (!*o_tp_loc) |
2167 | *o_tp_loc = o_tp; | |
2168 | if (!*o_ltp_loc) | |
2169 | *o_ltp_loc = o_ltp; | |
2170 | o_tty->termios = *o_tp_loc; | |
2171 | o_tty->termios_locked = *o_ltp_loc; | |
2172 | driver->other->refcount++; | |
2173 | if (driver->subtype == PTY_TYPE_MASTER) | |
2174 | o_tty->count++; | |
2175 | ||
2176 | /* Establish the links in both directions */ | |
2177 | tty->link = o_tty; | |
2178 | o_tty->link = tty; | |
2179 | } | |
2180 | ||
37bdfb07 | 2181 | /* |
1da177e4 | 2182 | * All structures have been allocated, so now we install them. |
d5698c28 | 2183 | * Failures after this point use release_tty to clean up, so |
1da177e4 LT |
2184 | * there's no need to null out the local pointers. |
2185 | */ | |
37bdfb07 | 2186 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) |
1da177e4 | 2187 | driver->ttys[idx] = tty; |
37bdfb07 | 2188 | |
1da177e4 LT |
2189 | if (!*tp_loc) |
2190 | *tp_loc = tp; | |
2191 | if (!*ltp_loc) | |
2192 | *ltp_loc = ltp; | |
2193 | tty->termios = *tp_loc; | |
2194 | tty->termios_locked = *ltp_loc; | |
edc6afc5 AC |
2195 | /* Compatibility until drivers always set this */ |
2196 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
2197 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1da177e4 LT |
2198 | driver->refcount++; |
2199 | tty->count++; | |
2200 | ||
37bdfb07 | 2201 | /* |
1da177e4 | 2202 | * Structures all installed ... call the ldisc open routines. |
d5698c28 CH |
2203 | * If we fail here just call release_tty to clean up. No need |
2204 | * to decrement the use counts, as release_tty doesn't care. | |
1da177e4 LT |
2205 | */ |
2206 | ||
2207 | if (tty->ldisc.open) { | |
2208 | retval = (tty->ldisc.open)(tty); | |
2209 | if (retval) | |
2210 | goto release_mem_out; | |
2211 | } | |
2212 | if (o_tty && o_tty->ldisc.open) { | |
2213 | retval = (o_tty->ldisc.open)(o_tty); | |
2214 | if (retval) { | |
2215 | if (tty->ldisc.close) | |
2216 | (tty->ldisc.close)(tty); | |
2217 | goto release_mem_out; | |
2218 | } | |
2219 | tty_ldisc_enable(o_tty); | |
2220 | } | |
2221 | tty_ldisc_enable(tty); | |
2222 | goto success; | |
2223 | ||
2224 | /* | |
2225 | * This fast open can be used if the tty is already open. | |
2226 | * No memory is allocated, and the only failures are from | |
2227 | * attempting to open a closing tty or attempting multiple | |
2228 | * opens on a pty master. | |
2229 | */ | |
2230 | fast_track: | |
2231 | if (test_bit(TTY_CLOSING, &tty->flags)) { | |
2232 | retval = -EIO; | |
2233 | goto end_init; | |
2234 | } | |
2235 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
2236 | driver->subtype == PTY_TYPE_MASTER) { | |
2237 | /* | |
37bdfb07 | 2238 | * special case for PTY masters: only one open permitted, |
1da177e4 LT |
2239 | * and the slave side open count is incremented as well. |
2240 | */ | |
2241 | if (tty->count) { | |
2242 | retval = -EIO; | |
2243 | goto end_init; | |
2244 | } | |
2245 | tty->link->count++; | |
2246 | } | |
2247 | tty->count++; | |
2248 | tty->driver = driver; /* N.B. why do this every time?? */ | |
2249 | ||
2250 | /* FIXME */ | |
37bdfb07 | 2251 | if (!test_bit(TTY_LDISC, &tty->flags)) |
1da177e4 LT |
2252 | printk(KERN_ERR "init_dev but no ldisc\n"); |
2253 | success: | |
2254 | *ret_tty = tty; | |
37bdfb07 | 2255 | |
70522e12 | 2256 | /* All paths come through here to release the mutex */ |
1da177e4 LT |
2257 | end_init: |
2258 | return retval; | |
2259 | ||
2260 | /* Release locally allocated memory ... nothing placed in slots */ | |
2261 | free_mem_out: | |
735d5661 | 2262 | kfree(o_tp); |
1da177e4 LT |
2263 | if (o_tty) |
2264 | free_tty_struct(o_tty); | |
735d5661 JJ |
2265 | kfree(ltp); |
2266 | kfree(tp); | |
1da177e4 LT |
2267 | free_tty_struct(tty); |
2268 | ||
2269 | fail_no_mem: | |
2270 | module_put(driver->owner); | |
2271 | retval = -ENOMEM; | |
2272 | goto end_init; | |
2273 | ||
d5698c28 | 2274 | /* call the tty release_tty routine to clean out this slot */ |
1da177e4 | 2275 | release_mem_out: |
4050914f AM |
2276 | if (printk_ratelimit()) |
2277 | printk(KERN_INFO "init_dev: ldisc open failed, " | |
2278 | "clearing slot %d\n", idx); | |
d5698c28 | 2279 | release_tty(tty, idx); |
1da177e4 LT |
2280 | goto end_init; |
2281 | } | |
2282 | ||
af9b897e | 2283 | /** |
d5698c28 | 2284 | * release_one_tty - release tty structure memory |
af9b897e AC |
2285 | * |
2286 | * Releases memory associated with a tty structure, and clears out the | |
2287 | * driver table slots. This function is called when a device is no longer | |
2288 | * in use. It also gets called when setup of a device fails. | |
2289 | * | |
2290 | * Locking: | |
2291 | * tty_mutex - sometimes only | |
2292 | * takes the file list lock internally when working on the list | |
2293 | * of ttys that the driver keeps. | |
2294 | * FIXME: should we require tty_mutex is held here ?? | |
1da177e4 | 2295 | */ |
d5698c28 | 2296 | static void release_one_tty(struct tty_struct *tty, int idx) |
1da177e4 | 2297 | { |
1da177e4 | 2298 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
d5698c28 | 2299 | struct ktermios *tp; |
1da177e4 LT |
2300 | |
2301 | if (!devpts) | |
2302 | tty->driver->ttys[idx] = NULL; | |
d5698c28 | 2303 | |
1da177e4 LT |
2304 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
2305 | tp = tty->termios; | |
2306 | if (!devpts) | |
2307 | tty->driver->termios[idx] = NULL; | |
2308 | kfree(tp); | |
2309 | ||
2310 | tp = tty->termios_locked; | |
2311 | if (!devpts) | |
2312 | tty->driver->termios_locked[idx] = NULL; | |
2313 | kfree(tp); | |
2314 | } | |
2315 | ||
d5698c28 | 2316 | |
1da177e4 LT |
2317 | tty->magic = 0; |
2318 | tty->driver->refcount--; | |
d5698c28 | 2319 | |
1da177e4 LT |
2320 | file_list_lock(); |
2321 | list_del_init(&tty->tty_files); | |
2322 | file_list_unlock(); | |
d5698c28 | 2323 | |
1da177e4 LT |
2324 | free_tty_struct(tty); |
2325 | } | |
2326 | ||
d5698c28 CH |
2327 | /** |
2328 | * release_tty - release tty structure memory | |
2329 | * | |
2330 | * Release both @tty and a possible linked partner (think pty pair), | |
2331 | * and decrement the refcount of the backing module. | |
2332 | * | |
2333 | * Locking: | |
2334 | * tty_mutex - sometimes only | |
2335 | * takes the file list lock internally when working on the list | |
2336 | * of ttys that the driver keeps. | |
2337 | * FIXME: should we require tty_mutex is held here ?? | |
2338 | */ | |
2339 | static void release_tty(struct tty_struct *tty, int idx) | |
2340 | { | |
2341 | struct tty_driver *driver = tty->driver; | |
2342 | ||
2343 | if (tty->link) | |
2344 | release_one_tty(tty->link, idx); | |
2345 | release_one_tty(tty, idx); | |
2346 | module_put(driver->owner); | |
2347 | } | |
2348 | ||
1da177e4 LT |
2349 | /* |
2350 | * Even releasing the tty structures is a tricky business.. We have | |
2351 | * to be very careful that the structures are all released at the | |
2352 | * same time, as interrupts might otherwise get the wrong pointers. | |
2353 | * | |
2354 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
2355 | * lead to double frees or releasing memory still in use. | |
2356 | */ | |
37bdfb07 | 2357 | static void release_dev(struct file *filp) |
1da177e4 LT |
2358 | { |
2359 | struct tty_struct *tty, *o_tty; | |
2360 | int pty_master, tty_closing, o_tty_closing, do_sleep; | |
14a6283e | 2361 | int devpts; |
1da177e4 LT |
2362 | int idx; |
2363 | char buf[64]; | |
2364 | unsigned long flags; | |
37bdfb07 | 2365 | |
1da177e4 | 2366 | tty = (struct tty_struct *)filp->private_data; |
37bdfb07 AC |
2367 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, |
2368 | "release_dev")) | |
1da177e4 LT |
2369 | return; |
2370 | ||
2371 | check_tty_count(tty, "release_dev"); | |
2372 | ||
2373 | tty_fasync(-1, filp, 0); | |
2374 | ||
2375 | idx = tty->index; | |
2376 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2377 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2378 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; | |
1da177e4 LT |
2379 | o_tty = tty->link; |
2380 | ||
2381 | #ifdef TTY_PARANOIA_CHECK | |
2382 | if (idx < 0 || idx >= tty->driver->num) { | |
2383 | printk(KERN_DEBUG "release_dev: bad idx when trying to " | |
2384 | "free (%s)\n", tty->name); | |
2385 | return; | |
2386 | } | |
2387 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2388 | if (tty != tty->driver->ttys[idx]) { | |
2389 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " | |
2390 | "for (%s)\n", idx, tty->name); | |
2391 | return; | |
2392 | } | |
2393 | if (tty->termios != tty->driver->termios[idx]) { | |
2394 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " | |
2395 | "for (%s)\n", | |
2396 | idx, tty->name); | |
2397 | return; | |
2398 | } | |
2399 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { | |
2400 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " | |
2401 | "termios_locked for (%s)\n", | |
2402 | idx, tty->name); | |
2403 | return; | |
2404 | } | |
2405 | } | |
2406 | #endif | |
2407 | ||
2408 | #ifdef TTY_DEBUG_HANGUP | |
2409 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", | |
2410 | tty_name(tty, buf), tty->count); | |
2411 | #endif | |
2412 | ||
2413 | #ifdef TTY_PARANOIA_CHECK | |
2414 | if (tty->driver->other && | |
2415 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2416 | if (o_tty != tty->driver->other->ttys[idx]) { | |
2417 | printk(KERN_DEBUG "release_dev: other->table[%d] " | |
2418 | "not o_tty for (%s)\n", | |
2419 | idx, tty->name); | |
2420 | return; | |
2421 | } | |
2422 | if (o_tty->termios != tty->driver->other->termios[idx]) { | |
2423 | printk(KERN_DEBUG "release_dev: other->termios[%d] " | |
2424 | "not o_termios for (%s)\n", | |
2425 | idx, tty->name); | |
2426 | return; | |
2427 | } | |
37bdfb07 | 2428 | if (o_tty->termios_locked != |
1da177e4 LT |
2429 | tty->driver->other->termios_locked[idx]) { |
2430 | printk(KERN_DEBUG "release_dev: other->termios_locked[" | |
2431 | "%d] not o_termios_locked for (%s)\n", | |
2432 | idx, tty->name); | |
2433 | return; | |
2434 | } | |
2435 | if (o_tty->link != tty) { | |
2436 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); | |
2437 | return; | |
2438 | } | |
2439 | } | |
2440 | #endif | |
2441 | if (tty->driver->close) | |
2442 | tty->driver->close(tty, filp); | |
2443 | ||
2444 | /* | |
2445 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
2446 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
2447 | * wait queues and kick everyone out _before_ actually starting to | |
2448 | * close. This ensures that we won't block while releasing the tty | |
2449 | * structure. | |
2450 | * | |
2451 | * The test for the o_tty closing is necessary, since the master and | |
2452 | * slave sides may close in any order. If the slave side closes out | |
2453 | * first, its count will be one, since the master side holds an open. | |
2454 | * Thus this test wouldn't be triggered at the time the slave closes, | |
2455 | * so we do it now. | |
2456 | * | |
2457 | * Note that it's possible for the tty to be opened again while we're | |
2458 | * flushing out waiters. By recalculating the closing flags before | |
2459 | * each iteration we avoid any problems. | |
2460 | */ | |
2461 | while (1) { | |
2462 | /* Guard against races with tty->count changes elsewhere and | |
2463 | opens on /dev/tty */ | |
37bdfb07 | 2464 | |
70522e12 | 2465 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2466 | tty_closing = tty->count <= 1; |
2467 | o_tty_closing = o_tty && | |
2468 | (o_tty->count <= (pty_master ? 1 : 0)); | |
1da177e4 LT |
2469 | do_sleep = 0; |
2470 | ||
2471 | if (tty_closing) { | |
2472 | if (waitqueue_active(&tty->read_wait)) { | |
2473 | wake_up(&tty->read_wait); | |
2474 | do_sleep++; | |
2475 | } | |
2476 | if (waitqueue_active(&tty->write_wait)) { | |
2477 | wake_up(&tty->write_wait); | |
2478 | do_sleep++; | |
2479 | } | |
2480 | } | |
2481 | if (o_tty_closing) { | |
2482 | if (waitqueue_active(&o_tty->read_wait)) { | |
2483 | wake_up(&o_tty->read_wait); | |
2484 | do_sleep++; | |
2485 | } | |
2486 | if (waitqueue_active(&o_tty->write_wait)) { | |
2487 | wake_up(&o_tty->write_wait); | |
2488 | do_sleep++; | |
2489 | } | |
2490 | } | |
2491 | if (!do_sleep) | |
2492 | break; | |
2493 | ||
2494 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " | |
2495 | "active!\n", tty_name(tty, buf)); | |
70522e12 | 2496 | mutex_unlock(&tty_mutex); |
1da177e4 | 2497 | schedule(); |
37bdfb07 | 2498 | } |
1da177e4 LT |
2499 | |
2500 | /* | |
37bdfb07 AC |
2501 | * The closing flags are now consistent with the open counts on |
2502 | * both sides, and we've completed the last operation that could | |
1da177e4 LT |
2503 | * block, so it's safe to proceed with closing. |
2504 | */ | |
1da177e4 LT |
2505 | if (pty_master) { |
2506 | if (--o_tty->count < 0) { | |
2507 | printk(KERN_WARNING "release_dev: bad pty slave count " | |
2508 | "(%d) for %s\n", | |
2509 | o_tty->count, tty_name(o_tty, buf)); | |
2510 | o_tty->count = 0; | |
2511 | } | |
2512 | } | |
2513 | if (--tty->count < 0) { | |
2514 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", | |
2515 | tty->count, tty_name(tty, buf)); | |
2516 | tty->count = 0; | |
2517 | } | |
37bdfb07 | 2518 | |
1da177e4 LT |
2519 | /* |
2520 | * We've decremented tty->count, so we need to remove this file | |
2521 | * descriptor off the tty->tty_files list; this serves two | |
2522 | * purposes: | |
2523 | * - check_tty_count sees the correct number of file descriptors | |
2524 | * associated with this tty. | |
2525 | * - do_tty_hangup no longer sees this file descriptor as | |
2526 | * something that needs to be handled for hangups. | |
2527 | */ | |
2528 | file_kill(filp); | |
2529 | filp->private_data = NULL; | |
2530 | ||
2531 | /* | |
2532 | * Perform some housekeeping before deciding whether to return. | |
2533 | * | |
2534 | * Set the TTY_CLOSING flag if this was the last open. In the | |
2535 | * case of a pty we may have to wait around for the other side | |
2536 | * to close, and TTY_CLOSING makes sure we can't be reopened. | |
2537 | */ | |
37bdfb07 | 2538 | if (tty_closing) |
1da177e4 | 2539 | set_bit(TTY_CLOSING, &tty->flags); |
37bdfb07 | 2540 | if (o_tty_closing) |
1da177e4 LT |
2541 | set_bit(TTY_CLOSING, &o_tty->flags); |
2542 | ||
2543 | /* | |
2544 | * If _either_ side is closing, make sure there aren't any | |
2545 | * processes that still think tty or o_tty is their controlling | |
2546 | * tty. | |
2547 | */ | |
2548 | if (tty_closing || o_tty_closing) { | |
1da177e4 | 2549 | read_lock(&tasklist_lock); |
24ec839c | 2550 | session_clear_tty(tty->session); |
1da177e4 | 2551 | if (o_tty) |
24ec839c | 2552 | session_clear_tty(o_tty->session); |
1da177e4 LT |
2553 | read_unlock(&tasklist_lock); |
2554 | } | |
2555 | ||
70522e12 | 2556 | mutex_unlock(&tty_mutex); |
da965822 | 2557 | |
1da177e4 LT |
2558 | /* check whether both sides are closing ... */ |
2559 | if (!tty_closing || (o_tty && !o_tty_closing)) | |
2560 | return; | |
37bdfb07 | 2561 | |
1da177e4 LT |
2562 | #ifdef TTY_DEBUG_HANGUP |
2563 | printk(KERN_DEBUG "freeing tty structure..."); | |
2564 | #endif | |
2565 | /* | |
2566 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then | |
2567 | * kill any delayed work. As this is the final close it does not | |
2568 | * race with the set_ldisc code path. | |
2569 | */ | |
2570 | clear_bit(TTY_LDISC, &tty->flags); | |
33f0f88f | 2571 | cancel_delayed_work(&tty->buf.work); |
1da177e4 LT |
2572 | |
2573 | /* | |
33f0f88f | 2574 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 | 2575 | */ |
37bdfb07 | 2576 | |
1da177e4 | 2577 | flush_scheduled_work(); |
37bdfb07 | 2578 | |
1da177e4 LT |
2579 | /* |
2580 | * Wait for any short term users (we know they are just driver | |
2581 | * side waiters as the file is closing so user count on the file | |
2582 | * side is zero. | |
2583 | */ | |
2584 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
37bdfb07 | 2585 | while (tty->ldisc.refcount) { |
1da177e4 LT |
2586 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
2587 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); | |
2588 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2589 | } | |
2590 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2591 | /* | |
2592 | * Shutdown the current line discipline, and reset it to N_TTY. | |
2593 | * N.B. why reset ldisc when we're releasing the memory?? | |
2594 | * | |
2595 | * FIXME: this MUST get fixed for the new reflocking | |
2596 | */ | |
2597 | if (tty->ldisc.close) | |
2598 | (tty->ldisc.close)(tty); | |
2599 | tty_ldisc_put(tty->ldisc.num); | |
37bdfb07 | 2600 | |
1da177e4 LT |
2601 | /* |
2602 | * Switch the line discipline back | |
2603 | */ | |
2604 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
37bdfb07 | 2605 | tty_set_termios_ldisc(tty, N_TTY); |
1da177e4 LT |
2606 | if (o_tty) { |
2607 | /* FIXME: could o_tty be in setldisc here ? */ | |
2608 | clear_bit(TTY_LDISC, &o_tty->flags); | |
2609 | if (o_tty->ldisc.close) | |
2610 | (o_tty->ldisc.close)(o_tty); | |
2611 | tty_ldisc_put(o_tty->ldisc.num); | |
2612 | tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); | |
37bdfb07 | 2613 | tty_set_termios_ldisc(o_tty, N_TTY); |
1da177e4 LT |
2614 | } |
2615 | /* | |
d5698c28 | 2616 | * The release_tty function takes care of the details of clearing |
1da177e4 LT |
2617 | * the slots and preserving the termios structure. |
2618 | */ | |
d5698c28 | 2619 | release_tty(tty, idx); |
1da177e4 LT |
2620 | |
2621 | #ifdef CONFIG_UNIX98_PTYS | |
2622 | /* Make this pty number available for reallocation */ | |
2623 | if (devpts) { | |
a6752f3f | 2624 | mutex_lock(&allocated_ptys_lock); |
1da177e4 | 2625 | idr_remove(&allocated_ptys, idx); |
a6752f3f | 2626 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2627 | } |
2628 | #endif | |
2629 | ||
2630 | } | |
2631 | ||
af9b897e AC |
2632 | /** |
2633 | * tty_open - open a tty device | |
2634 | * @inode: inode of device file | |
2635 | * @filp: file pointer to tty | |
1da177e4 | 2636 | * |
af9b897e AC |
2637 | * tty_open and tty_release keep up the tty count that contains the |
2638 | * number of opens done on a tty. We cannot use the inode-count, as | |
2639 | * different inodes might point to the same tty. | |
1da177e4 | 2640 | * |
af9b897e AC |
2641 | * Open-counting is needed for pty masters, as well as for keeping |
2642 | * track of serial lines: DTR is dropped when the last close happens. | |
2643 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
2644 | * | |
2645 | * The termios state of a pty is reset on first open so that | |
2646 | * settings don't persist across reuse. | |
2647 | * | |
24ec839c PZ |
2648 | * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. |
2649 | * tty->count should protect the rest. | |
2650 | * ->siglock protects ->signal/->sighand | |
1da177e4 | 2651 | */ |
af9b897e | 2652 | |
37bdfb07 | 2653 | static int tty_open(struct inode *inode, struct file *filp) |
1da177e4 LT |
2654 | { |
2655 | struct tty_struct *tty; | |
2656 | int noctty, retval; | |
2657 | struct tty_driver *driver; | |
2658 | int index; | |
2659 | dev_t device = inode->i_rdev; | |
2660 | unsigned short saved_flags = filp->f_flags; | |
2661 | ||
2662 | nonseekable_open(inode, filp); | |
37bdfb07 | 2663 | |
1da177e4 LT |
2664 | retry_open: |
2665 | noctty = filp->f_flags & O_NOCTTY; | |
2666 | index = -1; | |
2667 | retval = 0; | |
37bdfb07 | 2668 | |
70522e12 | 2669 | mutex_lock(&tty_mutex); |
1da177e4 | 2670 | |
37bdfb07 | 2671 | if (device == MKDEV(TTYAUX_MAJOR, 0)) { |
24ec839c PZ |
2672 | tty = get_current_tty(); |
2673 | if (!tty) { | |
70522e12 | 2674 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2675 | return -ENXIO; |
2676 | } | |
24ec839c PZ |
2677 | driver = tty->driver; |
2678 | index = tty->index; | |
1da177e4 LT |
2679 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
2680 | /* noctty = 1; */ | |
2681 | goto got_driver; | |
2682 | } | |
2683 | #ifdef CONFIG_VT | |
37bdfb07 | 2684 | if (device == MKDEV(TTY_MAJOR, 0)) { |
1da177e4 LT |
2685 | extern struct tty_driver *console_driver; |
2686 | driver = console_driver; | |
2687 | index = fg_console; | |
2688 | noctty = 1; | |
2689 | goto got_driver; | |
2690 | } | |
2691 | #endif | |
37bdfb07 | 2692 | if (device == MKDEV(TTYAUX_MAJOR, 1)) { |
1da177e4 LT |
2693 | driver = console_device(&index); |
2694 | if (driver) { | |
2695 | /* Don't let /dev/console block */ | |
2696 | filp->f_flags |= O_NONBLOCK; | |
2697 | noctty = 1; | |
2698 | goto got_driver; | |
2699 | } | |
70522e12 | 2700 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2701 | return -ENODEV; |
2702 | } | |
2703 | ||
2704 | driver = get_tty_driver(device, &index); | |
2705 | if (!driver) { | |
70522e12 | 2706 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2707 | return -ENODEV; |
2708 | } | |
2709 | got_driver: | |
2710 | retval = init_dev(driver, index, &tty); | |
70522e12 | 2711 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2712 | if (retval) |
2713 | return retval; | |
2714 | ||
2715 | filp->private_data = tty; | |
2716 | file_move(filp, &tty->tty_files); | |
2717 | check_tty_count(tty, "tty_open"); | |
2718 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2719 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2720 | noctty = 1; | |
2721 | #ifdef TTY_DEBUG_HANGUP | |
2722 | printk(KERN_DEBUG "opening %s...", tty->name); | |
2723 | #endif | |
2724 | if (!retval) { | |
2725 | if (tty->driver->open) | |
2726 | retval = tty->driver->open(tty, filp); | |
2727 | else | |
2728 | retval = -ENODEV; | |
2729 | } | |
2730 | filp->f_flags = saved_flags; | |
2731 | ||
37bdfb07 AC |
2732 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && |
2733 | !capable(CAP_SYS_ADMIN)) | |
1da177e4 LT |
2734 | retval = -EBUSY; |
2735 | ||
2736 | if (retval) { | |
2737 | #ifdef TTY_DEBUG_HANGUP | |
2738 | printk(KERN_DEBUG "error %d in opening %s...", retval, | |
2739 | tty->name); | |
2740 | #endif | |
2741 | release_dev(filp); | |
2742 | if (retval != -ERESTARTSYS) | |
2743 | return retval; | |
2744 | if (signal_pending(current)) | |
2745 | return retval; | |
2746 | schedule(); | |
2747 | /* | |
2748 | * Need to reset f_op in case a hangup happened. | |
2749 | */ | |
2750 | if (filp->f_op == &hung_up_tty_fops) | |
2751 | filp->f_op = &tty_fops; | |
2752 | goto retry_open; | |
2753 | } | |
24ec839c PZ |
2754 | |
2755 | mutex_lock(&tty_mutex); | |
2756 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2757 | if (!noctty && |
2758 | current->signal->leader && | |
2759 | !current->signal->tty && | |
ab521dc0 | 2760 | tty->session == NULL) |
2a65f1d9 | 2761 | __proc_set_tty(current, tty); |
24ec839c PZ |
2762 | spin_unlock_irq(¤t->sighand->siglock); |
2763 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
2764 | return 0; |
2765 | } | |
2766 | ||
2767 | #ifdef CONFIG_UNIX98_PTYS | |
af9b897e AC |
2768 | /** |
2769 | * ptmx_open - open a unix 98 pty master | |
2770 | * @inode: inode of device file | |
2771 | * @filp: file pointer to tty | |
2772 | * | |
2773 | * Allocate a unix98 pty master device from the ptmx driver. | |
2774 | * | |
2775 | * Locking: tty_mutex protects theinit_dev work. tty->count should | |
37bdfb07 | 2776 | * protect the rest. |
af9b897e AC |
2777 | * allocated_ptys_lock handles the list of free pty numbers |
2778 | */ | |
2779 | ||
37bdfb07 | 2780 | static int ptmx_open(struct inode *inode, struct file *filp) |
1da177e4 LT |
2781 | { |
2782 | struct tty_struct *tty; | |
2783 | int retval; | |
2784 | int index; | |
2785 | int idr_ret; | |
2786 | ||
2787 | nonseekable_open(inode, filp); | |
2788 | ||
2789 | /* find a device that is not in use. */ | |
a6752f3f | 2790 | mutex_lock(&allocated_ptys_lock); |
1da177e4 | 2791 | if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { |
a6752f3f | 2792 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2793 | return -ENOMEM; |
2794 | } | |
2795 | idr_ret = idr_get_new(&allocated_ptys, NULL, &index); | |
2796 | if (idr_ret < 0) { | |
a6752f3f | 2797 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2798 | if (idr_ret == -EAGAIN) |
2799 | return -ENOMEM; | |
2800 | return -EIO; | |
2801 | } | |
2802 | if (index >= pty_limit) { | |
2803 | idr_remove(&allocated_ptys, index); | |
a6752f3f | 2804 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2805 | return -EIO; |
2806 | } | |
a6752f3f | 2807 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 | 2808 | |
70522e12 | 2809 | mutex_lock(&tty_mutex); |
1da177e4 | 2810 | retval = init_dev(ptm_driver, index, &tty); |
70522e12 | 2811 | mutex_unlock(&tty_mutex); |
37bdfb07 | 2812 | |
1da177e4 LT |
2813 | if (retval) |
2814 | goto out; | |
2815 | ||
2816 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
2817 | filp->private_data = tty; | |
2818 | file_move(filp, &tty->tty_files); | |
2819 | ||
2820 | retval = -ENOMEM; | |
2821 | if (devpts_pty_new(tty->link)) | |
2822 | goto out1; | |
2823 | ||
2824 | check_tty_count(tty, "tty_open"); | |
2825 | retval = ptm_driver->open(tty, filp); | |
41126226 | 2826 | if (!retval) |
1da177e4 LT |
2827 | return 0; |
2828 | out1: | |
2829 | release_dev(filp); | |
9453a5ad | 2830 | return retval; |
1da177e4 | 2831 | out: |
a6752f3f | 2832 | mutex_lock(&allocated_ptys_lock); |
1da177e4 | 2833 | idr_remove(&allocated_ptys, index); |
a6752f3f | 2834 | mutex_unlock(&allocated_ptys_lock); |
1da177e4 LT |
2835 | return retval; |
2836 | } | |
2837 | #endif | |
2838 | ||
af9b897e AC |
2839 | /** |
2840 | * tty_release - vfs callback for close | |
2841 | * @inode: inode of tty | |
2842 | * @filp: file pointer for handle to tty | |
2843 | * | |
2844 | * Called the last time each file handle is closed that references | |
2845 | * this tty. There may however be several such references. | |
2846 | * | |
2847 | * Locking: | |
2848 | * Takes bkl. See release_dev | |
2849 | */ | |
2850 | ||
37bdfb07 | 2851 | static int tty_release(struct inode *inode, struct file *filp) |
1da177e4 LT |
2852 | { |
2853 | lock_kernel(); | |
2854 | release_dev(filp); | |
2855 | unlock_kernel(); | |
2856 | return 0; | |
2857 | } | |
2858 | ||
af9b897e AC |
2859 | /** |
2860 | * tty_poll - check tty status | |
2861 | * @filp: file being polled | |
2862 | * @wait: poll wait structures to update | |
2863 | * | |
2864 | * Call the line discipline polling method to obtain the poll | |
2865 | * status of the device. | |
2866 | * | |
2867 | * Locking: locks called line discipline but ldisc poll method | |
2868 | * may be re-entered freely by other callers. | |
2869 | */ | |
2870 | ||
37bdfb07 | 2871 | static unsigned int tty_poll(struct file *filp, poll_table *wait) |
1da177e4 | 2872 | { |
37bdfb07 | 2873 | struct tty_struct *tty; |
1da177e4 LT |
2874 | struct tty_ldisc *ld; |
2875 | int ret = 0; | |
2876 | ||
2877 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2878 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) |
1da177e4 | 2879 | return 0; |
37bdfb07 | 2880 | |
1da177e4 LT |
2881 | ld = tty_ldisc_ref_wait(tty); |
2882 | if (ld->poll) | |
2883 | ret = (ld->poll)(tty, filp, wait); | |
2884 | tty_ldisc_deref(ld); | |
2885 | return ret; | |
2886 | } | |
2887 | ||
37bdfb07 | 2888 | static int tty_fasync(int fd, struct file *filp, int on) |
1da177e4 | 2889 | { |
37bdfb07 | 2890 | struct tty_struct *tty; |
1da177e4 LT |
2891 | int retval; |
2892 | ||
2893 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2894 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) |
1da177e4 | 2895 | return 0; |
37bdfb07 | 2896 | |
1da177e4 LT |
2897 | retval = fasync_helper(fd, filp, on, &tty->fasync); |
2898 | if (retval <= 0) | |
2899 | return retval; | |
2900 | ||
2901 | if (on) { | |
ab521dc0 EB |
2902 | enum pid_type type; |
2903 | struct pid *pid; | |
1da177e4 LT |
2904 | if (!waitqueue_active(&tty->read_wait)) |
2905 | tty->minimum_to_wake = 1; | |
ab521dc0 EB |
2906 | if (tty->pgrp) { |
2907 | pid = tty->pgrp; | |
2908 | type = PIDTYPE_PGID; | |
2909 | } else { | |
2910 | pid = task_pid(current); | |
2911 | type = PIDTYPE_PID; | |
2912 | } | |
2913 | retval = __f_setown(filp, pid, type, 0); | |
1da177e4 LT |
2914 | if (retval) |
2915 | return retval; | |
2916 | } else { | |
2917 | if (!tty->fasync && !waitqueue_active(&tty->read_wait)) | |
2918 | tty->minimum_to_wake = N_TTY_BUF_SIZE; | |
2919 | } | |
2920 | return 0; | |
2921 | } | |
2922 | ||
af9b897e AC |
2923 | /** |
2924 | * tiocsti - fake input character | |
2925 | * @tty: tty to fake input into | |
2926 | * @p: pointer to character | |
2927 | * | |
3a4fa0a2 | 2928 | * Fake input to a tty device. Does the necessary locking and |
af9b897e AC |
2929 | * input management. |
2930 | * | |
2931 | * FIXME: does not honour flow control ?? | |
2932 | * | |
2933 | * Locking: | |
2934 | * Called functions take tty_ldisc_lock | |
2935 | * current->signal->tty check is safe without locks | |
28298232 AC |
2936 | * |
2937 | * FIXME: may race normal receive processing | |
af9b897e AC |
2938 | */ |
2939 | ||
1da177e4 LT |
2940 | static int tiocsti(struct tty_struct *tty, char __user *p) |
2941 | { | |
2942 | char ch, mbz = 0; | |
2943 | struct tty_ldisc *ld; | |
37bdfb07 | 2944 | |
1da177e4 LT |
2945 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) |
2946 | return -EPERM; | |
2947 | if (get_user(ch, p)) | |
2948 | return -EFAULT; | |
2949 | ld = tty_ldisc_ref_wait(tty); | |
2950 | ld->receive_buf(tty, &ch, &mbz, 1); | |
2951 | tty_ldisc_deref(ld); | |
2952 | return 0; | |
2953 | } | |
2954 | ||
af9b897e AC |
2955 | /** |
2956 | * tiocgwinsz - implement window query ioctl | |
2957 | * @tty; tty | |
2958 | * @arg: user buffer for result | |
2959 | * | |
808a0d38 | 2960 | * Copies the kernel idea of the window size into the user buffer. |
af9b897e | 2961 | * |
24ec839c | 2962 | * Locking: tty->termios_mutex is taken to ensure the winsize data |
808a0d38 | 2963 | * is consistent. |
af9b897e AC |
2964 | */ |
2965 | ||
37bdfb07 | 2966 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg) |
1da177e4 | 2967 | { |
808a0d38 AC |
2968 | int err; |
2969 | ||
5785c95b | 2970 | mutex_lock(&tty->termios_mutex); |
808a0d38 | 2971 | err = copy_to_user(arg, &tty->winsize, sizeof(*arg)); |
5785c95b | 2972 | mutex_unlock(&tty->termios_mutex); |
808a0d38 AC |
2973 | |
2974 | return err ? -EFAULT: 0; | |
1da177e4 LT |
2975 | } |
2976 | ||
af9b897e AC |
2977 | /** |
2978 | * tiocswinsz - implement window size set ioctl | |
2979 | * @tty; tty | |
2980 | * @arg: user buffer for result | |
2981 | * | |
2982 | * Copies the user idea of the window size to the kernel. Traditionally | |
2983 | * this is just advisory information but for the Linux console it | |
2984 | * actually has driver level meaning and triggers a VC resize. | |
2985 | * | |
2986 | * Locking: | |
ca9bda00 AC |
2987 | * Called function use the console_sem is used to ensure we do |
2988 | * not try and resize the console twice at once. | |
24ec839c PZ |
2989 | * The tty->termios_mutex is used to ensure we don't double |
2990 | * resize and get confused. Lock order - tty->termios_mutex before | |
ca9bda00 | 2991 | * console sem |
af9b897e AC |
2992 | */ |
2993 | ||
1da177e4 | 2994 | static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, |
37bdfb07 | 2995 | struct winsize __user *arg) |
1da177e4 LT |
2996 | { |
2997 | struct winsize tmp_ws; | |
2998 | ||
2999 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
3000 | return -EFAULT; | |
ca9bda00 | 3001 | |
5785c95b | 3002 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 3003 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
ca9bda00 AC |
3004 | goto done; |
3005 | ||
1da177e4 LT |
3006 | #ifdef CONFIG_VT |
3007 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { | |
5785c95b AV |
3008 | if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, |
3009 | tmp_ws.ws_row)) { | |
3010 | mutex_unlock(&tty->termios_mutex); | |
37bdfb07 | 3011 | return -ENXIO; |
ca9bda00 | 3012 | } |
1da177e4 LT |
3013 | } |
3014 | #endif | |
ab521dc0 EB |
3015 | if (tty->pgrp) |
3016 | kill_pgrp(tty->pgrp, SIGWINCH, 1); | |
3017 | if ((real_tty->pgrp != tty->pgrp) && real_tty->pgrp) | |
3018 | kill_pgrp(real_tty->pgrp, SIGWINCH, 1); | |
1da177e4 LT |
3019 | tty->winsize = tmp_ws; |
3020 | real_tty->winsize = tmp_ws; | |
ca9bda00 | 3021 | done: |
5785c95b | 3022 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
3023 | return 0; |
3024 | } | |
3025 | ||
af9b897e AC |
3026 | /** |
3027 | * tioccons - allow admin to move logical console | |
3028 | * @file: the file to become console | |
3029 | * | |
3030 | * Allow the adminstrator to move the redirected console device | |
3031 | * | |
3032 | * Locking: uses redirect_lock to guard the redirect information | |
3033 | */ | |
3034 | ||
1da177e4 LT |
3035 | static int tioccons(struct file *file) |
3036 | { | |
3037 | if (!capable(CAP_SYS_ADMIN)) | |
3038 | return -EPERM; | |
3039 | if (file->f_op->write == redirected_tty_write) { | |
3040 | struct file *f; | |
3041 | spin_lock(&redirect_lock); | |
3042 | f = redirect; | |
3043 | redirect = NULL; | |
3044 | spin_unlock(&redirect_lock); | |
3045 | if (f) | |
3046 | fput(f); | |
3047 | return 0; | |
3048 | } | |
3049 | spin_lock(&redirect_lock); | |
3050 | if (redirect) { | |
3051 | spin_unlock(&redirect_lock); | |
3052 | return -EBUSY; | |
3053 | } | |
3054 | get_file(file); | |
3055 | redirect = file; | |
3056 | spin_unlock(&redirect_lock); | |
3057 | return 0; | |
3058 | } | |
3059 | ||
af9b897e AC |
3060 | /** |
3061 | * fionbio - non blocking ioctl | |
3062 | * @file: file to set blocking value | |
3063 | * @p: user parameter | |
3064 | * | |
3065 | * Historical tty interfaces had a blocking control ioctl before | |
3066 | * the generic functionality existed. This piece of history is preserved | |
3067 | * in the expected tty API of posix OS's. | |
3068 | * | |
3069 | * Locking: none, the open fle handle ensures it won't go away. | |
3070 | */ | |
1da177e4 LT |
3071 | |
3072 | static int fionbio(struct file *file, int __user *p) | |
3073 | { | |
3074 | int nonblock; | |
3075 | ||
3076 | if (get_user(nonblock, p)) | |
3077 | return -EFAULT; | |
3078 | ||
04f378b1 AC |
3079 | /* file->f_flags is still BKL protected in the fs layer - vomit */ |
3080 | lock_kernel(); | |
1da177e4 LT |
3081 | if (nonblock) |
3082 | file->f_flags |= O_NONBLOCK; | |
3083 | else | |
3084 | file->f_flags &= ~O_NONBLOCK; | |
04f378b1 | 3085 | unlock_kernel(); |
1da177e4 LT |
3086 | return 0; |
3087 | } | |
3088 | ||
af9b897e AC |
3089 | /** |
3090 | * tiocsctty - set controlling tty | |
3091 | * @tty: tty structure | |
3092 | * @arg: user argument | |
3093 | * | |
3094 | * This ioctl is used to manage job control. It permits a session | |
3095 | * leader to set this tty as the controlling tty for the session. | |
3096 | * | |
3097 | * Locking: | |
28298232 | 3098 | * Takes tty_mutex() to protect tty instance |
24ec839c PZ |
3099 | * Takes tasklist_lock internally to walk sessions |
3100 | * Takes ->siglock() when updating signal->tty | |
af9b897e AC |
3101 | */ |
3102 | ||
1da177e4 LT |
3103 | static int tiocsctty(struct tty_struct *tty, int arg) |
3104 | { | |
24ec839c | 3105 | int ret = 0; |
ab521dc0 | 3106 | if (current->signal->leader && (task_session(current) == tty->session)) |
24ec839c PZ |
3107 | return ret; |
3108 | ||
3109 | mutex_lock(&tty_mutex); | |
1da177e4 LT |
3110 | /* |
3111 | * The process must be a session leader and | |
3112 | * not have a controlling tty already. | |
3113 | */ | |
24ec839c PZ |
3114 | if (!current->signal->leader || current->signal->tty) { |
3115 | ret = -EPERM; | |
3116 | goto unlock; | |
3117 | } | |
3118 | ||
ab521dc0 | 3119 | if (tty->session) { |
1da177e4 LT |
3120 | /* |
3121 | * This tty is already the controlling | |
3122 | * tty for another session group! | |
3123 | */ | |
37bdfb07 | 3124 | if (arg == 1 && capable(CAP_SYS_ADMIN)) { |
1da177e4 LT |
3125 | /* |
3126 | * Steal it away | |
3127 | */ | |
1da177e4 | 3128 | read_lock(&tasklist_lock); |
24ec839c | 3129 | session_clear_tty(tty->session); |
1da177e4 | 3130 | read_unlock(&tasklist_lock); |
24ec839c PZ |
3131 | } else { |
3132 | ret = -EPERM; | |
3133 | goto unlock; | |
3134 | } | |
1da177e4 | 3135 | } |
24ec839c PZ |
3136 | proc_set_tty(current, tty); |
3137 | unlock: | |
28298232 | 3138 | mutex_unlock(&tty_mutex); |
24ec839c | 3139 | return ret; |
1da177e4 LT |
3140 | } |
3141 | ||
af9b897e AC |
3142 | /** |
3143 | * tiocgpgrp - get process group | |
3144 | * @tty: tty passed by user | |
3145 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3146 | * @p: returned pid | |
3147 | * | |
3148 | * Obtain the process group of the tty. If there is no process group | |
3149 | * return an error. | |
3150 | * | |
24ec839c | 3151 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3152 | */ |
3153 | ||
1da177e4 LT |
3154 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3155 | { | |
3156 | /* | |
3157 | * (tty == real_tty) is a cheap way of | |
3158 | * testing if the tty is NOT a master pty. | |
3159 | */ | |
3160 | if (tty == real_tty && current->signal->tty != real_tty) | |
3161 | return -ENOTTY; | |
b488893a | 3162 | return put_user(pid_vnr(real_tty->pgrp), p); |
1da177e4 LT |
3163 | } |
3164 | ||
af9b897e AC |
3165 | /** |
3166 | * tiocspgrp - attempt to set process group | |
3167 | * @tty: tty passed by user | |
3168 | * @real_tty: tty side device matching tty passed by user | |
3169 | * @p: pid pointer | |
3170 | * | |
3171 | * Set the process group of the tty to the session passed. Only | |
3172 | * permitted where the tty session is our session. | |
3173 | * | |
04f378b1 | 3174 | * Locking: RCU |
af9b897e AC |
3175 | */ |
3176 | ||
1da177e4 LT |
3177 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3178 | { | |
04a2e6a5 EB |
3179 | struct pid *pgrp; |
3180 | pid_t pgrp_nr; | |
1da177e4 LT |
3181 | int retval = tty_check_change(real_tty); |
3182 | ||
3183 | if (retval == -EIO) | |
3184 | return -ENOTTY; | |
3185 | if (retval) | |
3186 | return retval; | |
3187 | if (!current->signal->tty || | |
3188 | (current->signal->tty != real_tty) || | |
ab521dc0 | 3189 | (real_tty->session != task_session(current))) |
1da177e4 | 3190 | return -ENOTTY; |
04a2e6a5 | 3191 | if (get_user(pgrp_nr, p)) |
1da177e4 | 3192 | return -EFAULT; |
04a2e6a5 | 3193 | if (pgrp_nr < 0) |
1da177e4 | 3194 | return -EINVAL; |
04a2e6a5 | 3195 | rcu_read_lock(); |
b488893a | 3196 | pgrp = find_vpid(pgrp_nr); |
04a2e6a5 EB |
3197 | retval = -ESRCH; |
3198 | if (!pgrp) | |
3199 | goto out_unlock; | |
3200 | retval = -EPERM; | |
3201 | if (session_of_pgrp(pgrp) != task_session(current)) | |
3202 | goto out_unlock; | |
3203 | retval = 0; | |
ab521dc0 EB |
3204 | put_pid(real_tty->pgrp); |
3205 | real_tty->pgrp = get_pid(pgrp); | |
04a2e6a5 EB |
3206 | out_unlock: |
3207 | rcu_read_unlock(); | |
3208 | return retval; | |
1da177e4 LT |
3209 | } |
3210 | ||
af9b897e AC |
3211 | /** |
3212 | * tiocgsid - get session id | |
3213 | * @tty: tty passed by user | |
3214 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3215 | * @p: pointer to returned session id | |
3216 | * | |
3217 | * Obtain the session id of the tty. If there is no session | |
3218 | * return an error. | |
3219 | * | |
24ec839c | 3220 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3221 | */ |
3222 | ||
1da177e4 LT |
3223 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3224 | { | |
3225 | /* | |
3226 | * (tty == real_tty) is a cheap way of | |
3227 | * testing if the tty is NOT a master pty. | |
3228 | */ | |
3229 | if (tty == real_tty && current->signal->tty != real_tty) | |
3230 | return -ENOTTY; | |
ab521dc0 | 3231 | if (!real_tty->session) |
1da177e4 | 3232 | return -ENOTTY; |
b488893a | 3233 | return put_user(pid_vnr(real_tty->session), p); |
1da177e4 LT |
3234 | } |
3235 | ||
af9b897e AC |
3236 | /** |
3237 | * tiocsetd - set line discipline | |
3238 | * @tty: tty device | |
3239 | * @p: pointer to user data | |
3240 | * | |
3241 | * Set the line discipline according to user request. | |
3242 | * | |
3243 | * Locking: see tty_set_ldisc, this function is just a helper | |
3244 | */ | |
3245 | ||
1da177e4 LT |
3246 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
3247 | { | |
3248 | int ldisc; | |
04f378b1 | 3249 | int ret; |
1da177e4 LT |
3250 | |
3251 | if (get_user(ldisc, p)) | |
3252 | return -EFAULT; | |
04f378b1 AC |
3253 | |
3254 | lock_kernel(); | |
3255 | ret = tty_set_ldisc(tty, ldisc); | |
3256 | unlock_kernel(); | |
3257 | ||
3258 | return ret; | |
1da177e4 LT |
3259 | } |
3260 | ||
af9b897e AC |
3261 | /** |
3262 | * send_break - performed time break | |
3263 | * @tty: device to break on | |
3264 | * @duration: timeout in mS | |
3265 | * | |
3266 | * Perform a timed break on hardware that lacks its own driver level | |
3267 | * timed break functionality. | |
3268 | * | |
3269 | * Locking: | |
28298232 | 3270 | * atomic_write_lock serializes |
af9b897e | 3271 | * |
af9b897e AC |
3272 | */ |
3273 | ||
b20f3ae5 | 3274 | static int send_break(struct tty_struct *tty, unsigned int duration) |
1da177e4 | 3275 | { |
04f378b1 AC |
3276 | int retval = -EINTR; |
3277 | ||
3278 | lock_kernel(); | |
9c1729db | 3279 | if (tty_write_lock(tty, 0) < 0) |
04f378b1 | 3280 | goto out; |
1da177e4 | 3281 | tty->driver->break_ctl(tty, -1); |
9c1729db | 3282 | if (!signal_pending(current)) |
b20f3ae5 | 3283 | msleep_interruptible(duration); |
1da177e4 | 3284 | tty->driver->break_ctl(tty, 0); |
9c1729db | 3285 | tty_write_unlock(tty); |
04f378b1 AC |
3286 | if (!signal_pending(current)) |
3287 | retval = 0; | |
3288 | out: | |
3289 | unlock_kernel(); | |
3290 | return retval; | |
1da177e4 LT |
3291 | } |
3292 | ||
af9b897e AC |
3293 | /** |
3294 | * tiocmget - get modem status | |
3295 | * @tty: tty device | |
3296 | * @file: user file pointer | |
3297 | * @p: pointer to result | |
3298 | * | |
3299 | * Obtain the modem status bits from the tty driver if the feature | |
3300 | * is supported. Return -EINVAL if it is not available. | |
3301 | * | |
3302 | * Locking: none (up to the driver) | |
3303 | */ | |
3304 | ||
3305 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) | |
1da177e4 LT |
3306 | { |
3307 | int retval = -EINVAL; | |
3308 | ||
3309 | if (tty->driver->tiocmget) { | |
04f378b1 | 3310 | lock_kernel(); |
1da177e4 | 3311 | retval = tty->driver->tiocmget(tty, file); |
04f378b1 | 3312 | unlock_kernel(); |
1da177e4 LT |
3313 | |
3314 | if (retval >= 0) | |
3315 | retval = put_user(retval, p); | |
3316 | } | |
3317 | return retval; | |
3318 | } | |
3319 | ||
af9b897e AC |
3320 | /** |
3321 | * tiocmset - set modem status | |
3322 | * @tty: tty device | |
3323 | * @file: user file pointer | |
3324 | * @cmd: command - clear bits, set bits or set all | |
3325 | * @p: pointer to desired bits | |
3326 | * | |
3327 | * Set the modem status bits from the tty driver if the feature | |
3328 | * is supported. Return -EINVAL if it is not available. | |
3329 | * | |
3330 | * Locking: none (up to the driver) | |
3331 | */ | |
3332 | ||
3333 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, | |
1da177e4 LT |
3334 | unsigned __user *p) |
3335 | { | |
3336 | int retval = -EINVAL; | |
3337 | ||
3338 | if (tty->driver->tiocmset) { | |
3339 | unsigned int set, clear, val; | |
3340 | ||
3341 | retval = get_user(val, p); | |
3342 | if (retval) | |
3343 | return retval; | |
3344 | ||
3345 | set = clear = 0; | |
3346 | switch (cmd) { | |
3347 | case TIOCMBIS: | |
3348 | set = val; | |
3349 | break; | |
3350 | case TIOCMBIC: | |
3351 | clear = val; | |
3352 | break; | |
3353 | case TIOCMSET: | |
3354 | set = val; | |
3355 | clear = ~val; | |
3356 | break; | |
3357 | } | |
3358 | ||
3359 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3360 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3361 | ||
04f378b1 | 3362 | lock_kernel(); |
1da177e4 | 3363 | retval = tty->driver->tiocmset(tty, file, set, clear); |
04f378b1 | 3364 | unlock_kernel(); |
1da177e4 LT |
3365 | } |
3366 | return retval; | |
3367 | } | |
3368 | ||
3369 | /* | |
3370 | * Split this up, as gcc can choke on it otherwise.. | |
3371 | */ | |
04f378b1 | 3372 | long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
3373 | { |
3374 | struct tty_struct *tty, *real_tty; | |
3375 | void __user *p = (void __user *)arg; | |
3376 | int retval; | |
3377 | struct tty_ldisc *ld; | |
04f378b1 | 3378 | struct inode *inode = file->f_dentry->d_inode; |
37bdfb07 | 3379 | |
1da177e4 LT |
3380 | tty = (struct tty_struct *)file->private_data; |
3381 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3382 | return -EINVAL; | |
3383 | ||
3384 | real_tty = tty; | |
3385 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
3386 | tty->driver->subtype == PTY_TYPE_MASTER) | |
3387 | real_tty = tty->link; | |
3388 | ||
3389 | /* | |
3390 | * Break handling by driver | |
3391 | */ | |
04f378b1 AC |
3392 | |
3393 | retval = -EINVAL; | |
3394 | ||
1da177e4 | 3395 | if (!tty->driver->break_ctl) { |
37bdfb07 | 3396 | switch (cmd) { |
1da177e4 LT |
3397 | case TIOCSBRK: |
3398 | case TIOCCBRK: | |
04f378b1 AC |
3399 | if (tty->driver->ioctl) { |
3400 | lock_kernel(); | |
3401 | retval = tty->driver->ioctl(tty, file, cmd, arg); | |
3402 | unlock_kernel(); | |
3403 | } | |
3404 | return retval; | |
37bdfb07 | 3405 | |
1da177e4 LT |
3406 | /* These two ioctl's always return success; even if */ |
3407 | /* the driver doesn't support them. */ | |
3408 | case TCSBRK: | |
3409 | case TCSBRKP: | |
3410 | if (!tty->driver->ioctl) | |
3411 | return 0; | |
04f378b1 | 3412 | lock_kernel(); |
1da177e4 | 3413 | retval = tty->driver->ioctl(tty, file, cmd, arg); |
04f378b1 | 3414 | unlock_kernel(); |
1da177e4 LT |
3415 | if (retval == -ENOIOCTLCMD) |
3416 | retval = 0; | |
3417 | return retval; | |
3418 | } | |
3419 | } | |
3420 | ||
3421 | /* | |
3422 | * Factor out some common prep work | |
3423 | */ | |
3424 | switch (cmd) { | |
3425 | case TIOCSETD: | |
3426 | case TIOCSBRK: | |
3427 | case TIOCCBRK: | |
3428 | case TCSBRK: | |
37bdfb07 | 3429 | case TCSBRKP: |
1da177e4 LT |
3430 | retval = tty_check_change(tty); |
3431 | if (retval) | |
3432 | return retval; | |
3433 | if (cmd != TIOCCBRK) { | |
04f378b1 | 3434 | lock_kernel(); |
1da177e4 | 3435 | tty_wait_until_sent(tty, 0); |
04f378b1 | 3436 | unlock_kernel(); |
1da177e4 LT |
3437 | if (signal_pending(current)) |
3438 | return -EINTR; | |
3439 | } | |
3440 | break; | |
3441 | } | |
3442 | ||
3443 | switch (cmd) { | |
37bdfb07 AC |
3444 | case TIOCSTI: |
3445 | return tiocsti(tty, p); | |
3446 | case TIOCGWINSZ: | |
3447 | return tiocgwinsz(tty, p); | |
3448 | case TIOCSWINSZ: | |
3449 | return tiocswinsz(tty, real_tty, p); | |
3450 | case TIOCCONS: | |
3451 | return real_tty != tty ? -EINVAL : tioccons(file); | |
3452 | case FIONBIO: | |
3453 | return fionbio(file, p); | |
3454 | case TIOCEXCL: | |
3455 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
3456 | return 0; | |
3457 | case TIOCNXCL: | |
3458 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
3459 | return 0; | |
3460 | case TIOCNOTTY: | |
3461 | if (current->signal->tty != tty) | |
3462 | return -ENOTTY; | |
3463 | no_tty(); | |
3464 | return 0; | |
3465 | case TIOCSCTTY: | |
3466 | return tiocsctty(tty, arg); | |
3467 | case TIOCGPGRP: | |
3468 | return tiocgpgrp(tty, real_tty, p); | |
3469 | case TIOCSPGRP: | |
3470 | return tiocspgrp(tty, real_tty, p); | |
3471 | case TIOCGSID: | |
3472 | return tiocgsid(tty, real_tty, p); | |
3473 | case TIOCGETD: | |
3474 | /* FIXME: check this is ok */ | |
3475 | return put_user(tty->ldisc.num, (int __user *)p); | |
3476 | case TIOCSETD: | |
3477 | return tiocsetd(tty, p); | |
1da177e4 | 3478 | #ifdef CONFIG_VT |
37bdfb07 AC |
3479 | case TIOCLINUX: |
3480 | return tioclinux(tty, arg); | |
1da177e4 | 3481 | #endif |
37bdfb07 AC |
3482 | /* |
3483 | * Break handling | |
3484 | */ | |
3485 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
04f378b1 | 3486 | lock_kernel(); |
37bdfb07 | 3487 | tty->driver->break_ctl(tty, -1); |
04f378b1 | 3488 | unlock_kernel(); |
37bdfb07 | 3489 | return 0; |
1da177e4 | 3490 | |
37bdfb07 | 3491 | case TIOCCBRK: /* Turn break off, unconditionally */ |
04f378b1 | 3492 | lock_kernel(); |
37bdfb07 | 3493 | tty->driver->break_ctl(tty, 0); |
04f378b1 | 3494 | unlock_kernel(); |
37bdfb07 AC |
3495 | return 0; |
3496 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
3497 | /* non-zero arg means wait for all output data | |
3498 | * to be sent (performed above) but don't send break. | |
3499 | * This is used by the tcdrain() termios function. | |
3500 | */ | |
3501 | if (!arg) | |
3502 | return send_break(tty, 250); | |
3503 | return 0; | |
3504 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
3505 | return send_break(tty, arg ? arg*100 : 250); | |
3506 | ||
3507 | case TIOCMGET: | |
3508 | return tty_tiocmget(tty, file, p); | |
3509 | case TIOCMSET: | |
3510 | case TIOCMBIC: | |
3511 | case TIOCMBIS: | |
3512 | return tty_tiocmset(tty, file, cmd, p); | |
3513 | case TCFLSH: | |
3514 | switch (arg) { | |
3515 | case TCIFLUSH: | |
3516 | case TCIOFLUSH: | |
3517 | /* flush tty buffer and allow ldisc to process ioctl */ | |
3518 | tty_buffer_flush(tty); | |
c5c34d48 | 3519 | break; |
37bdfb07 AC |
3520 | } |
3521 | break; | |
1da177e4 LT |
3522 | } |
3523 | if (tty->driver->ioctl) { | |
04f378b1 | 3524 | lock_kernel(); |
1da177e4 | 3525 | retval = (tty->driver->ioctl)(tty, file, cmd, arg); |
04f378b1 | 3526 | unlock_kernel(); |
1da177e4 LT |
3527 | if (retval != -ENOIOCTLCMD) |
3528 | return retval; | |
3529 | } | |
3530 | ld = tty_ldisc_ref_wait(tty); | |
3531 | retval = -EINVAL; | |
3532 | if (ld->ioctl) { | |
04f378b1 | 3533 | lock_kernel(); |
1da177e4 | 3534 | retval = ld->ioctl(tty, file, cmd, arg); |
04f378b1 | 3535 | unlock_kernel(); |
1da177e4 LT |
3536 | if (retval == -ENOIOCTLCMD) |
3537 | retval = -EINVAL; | |
3538 | } | |
3539 | tty_ldisc_deref(ld); | |
3540 | return retval; | |
3541 | } | |
3542 | ||
e10cc1df | 3543 | #ifdef CONFIG_COMPAT |
37bdfb07 | 3544 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
e10cc1df PF |
3545 | unsigned long arg) |
3546 | { | |
3547 | struct inode *inode = file->f_dentry->d_inode; | |
3548 | struct tty_struct *tty = file->private_data; | |
3549 | struct tty_ldisc *ld; | |
3550 | int retval = -ENOIOCTLCMD; | |
3551 | ||
3552 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3553 | return -EINVAL; | |
3554 | ||
3555 | if (tty->driver->compat_ioctl) { | |
3556 | retval = (tty->driver->compat_ioctl)(tty, file, cmd, arg); | |
3557 | if (retval != -ENOIOCTLCMD) | |
3558 | return retval; | |
3559 | } | |
3560 | ||
3561 | ld = tty_ldisc_ref_wait(tty); | |
3562 | if (ld->compat_ioctl) | |
3563 | retval = ld->compat_ioctl(tty, file, cmd, arg); | |
3564 | tty_ldisc_deref(ld); | |
3565 | ||
3566 | return retval; | |
3567 | } | |
3568 | #endif | |
1da177e4 LT |
3569 | |
3570 | /* | |
3571 | * This implements the "Secure Attention Key" --- the idea is to | |
3572 | * prevent trojan horses by killing all processes associated with this | |
3573 | * tty when the user hits the "Secure Attention Key". Required for | |
3574 | * super-paranoid applications --- see the Orange Book for more details. | |
37bdfb07 | 3575 | * |
1da177e4 LT |
3576 | * This code could be nicer; ideally it should send a HUP, wait a few |
3577 | * seconds, then send a INT, and then a KILL signal. But you then | |
3578 | * have to coordinate with the init process, since all processes associated | |
3579 | * with the current tty must be dead before the new getty is allowed | |
3580 | * to spawn. | |
3581 | * | |
3582 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
3583 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
3584 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
3585 | * | |
3586 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
3587 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
3588 | */ | |
8b6312f4 | 3589 | void __do_SAK(struct tty_struct *tty) |
1da177e4 LT |
3590 | { |
3591 | #ifdef TTY_SOFT_SAK | |
3592 | tty_hangup(tty); | |
3593 | #else | |
652486fb | 3594 | struct task_struct *g, *p; |
ab521dc0 | 3595 | struct pid *session; |
1da177e4 LT |
3596 | int i; |
3597 | struct file *filp; | |
badf1662 | 3598 | struct fdtable *fdt; |
37bdfb07 | 3599 | |
1da177e4 LT |
3600 | if (!tty) |
3601 | return; | |
24ec839c | 3602 | session = tty->session; |
37bdfb07 | 3603 | |
b3f13deb | 3604 | tty_ldisc_flush(tty); |
1da177e4 LT |
3605 | |
3606 | if (tty->driver->flush_buffer) | |
3607 | tty->driver->flush_buffer(tty); | |
37bdfb07 | 3608 | |
1da177e4 | 3609 | read_lock(&tasklist_lock); |
652486fb | 3610 | /* Kill the entire session */ |
ab521dc0 | 3611 | do_each_pid_task(session, PIDTYPE_SID, p) { |
652486fb | 3612 | printk(KERN_NOTICE "SAK: killed process %d" |
a47afb0f | 3613 | " (%s): task_session_nr(p)==tty->session\n", |
ba25f9dc | 3614 | task_pid_nr(p), p->comm); |
652486fb | 3615 | send_sig(SIGKILL, p, 1); |
ab521dc0 | 3616 | } while_each_pid_task(session, PIDTYPE_SID, p); |
652486fb EB |
3617 | /* Now kill any processes that happen to have the |
3618 | * tty open. | |
3619 | */ | |
3620 | do_each_thread(g, p) { | |
3621 | if (p->signal->tty == tty) { | |
1da177e4 | 3622 | printk(KERN_NOTICE "SAK: killed process %d" |
a47afb0f | 3623 | " (%s): task_session_nr(p)==tty->session\n", |
ba25f9dc | 3624 | task_pid_nr(p), p->comm); |
1da177e4 LT |
3625 | send_sig(SIGKILL, p, 1); |
3626 | continue; | |
3627 | } | |
3628 | task_lock(p); | |
3629 | if (p->files) { | |
ca99c1da DS |
3630 | /* |
3631 | * We don't take a ref to the file, so we must | |
3632 | * hold ->file_lock instead. | |
3633 | */ | |
3634 | spin_lock(&p->files->file_lock); | |
badf1662 | 3635 | fdt = files_fdtable(p->files); |
37bdfb07 | 3636 | for (i = 0; i < fdt->max_fds; i++) { |
1da177e4 LT |
3637 | filp = fcheck_files(p->files, i); |
3638 | if (!filp) | |
3639 | continue; | |
3640 | if (filp->f_op->read == tty_read && | |
3641 | filp->private_data == tty) { | |
3642 | printk(KERN_NOTICE "SAK: killed process %d" | |
3643 | " (%s): fd#%d opened to the tty\n", | |
ba25f9dc | 3644 | task_pid_nr(p), p->comm, i); |
20ac9437 | 3645 | force_sig(SIGKILL, p); |
1da177e4 LT |
3646 | break; |
3647 | } | |
3648 | } | |
ca99c1da | 3649 | spin_unlock(&p->files->file_lock); |
1da177e4 LT |
3650 | } |
3651 | task_unlock(p); | |
652486fb | 3652 | } while_each_thread(g, p); |
1da177e4 LT |
3653 | read_unlock(&tasklist_lock); |
3654 | #endif | |
3655 | } | |
3656 | ||
8b6312f4 EB |
3657 | static void do_SAK_work(struct work_struct *work) |
3658 | { | |
3659 | struct tty_struct *tty = | |
3660 | container_of(work, struct tty_struct, SAK_work); | |
3661 | __do_SAK(tty); | |
3662 | } | |
3663 | ||
1da177e4 LT |
3664 | /* |
3665 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
3666 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
3667 | * the values which we write to it will be identical to the values which it | |
3668 | * already has. --akpm | |
3669 | */ | |
3670 | void do_SAK(struct tty_struct *tty) | |
3671 | { | |
3672 | if (!tty) | |
3673 | return; | |
1da177e4 LT |
3674 | schedule_work(&tty->SAK_work); |
3675 | } | |
3676 | ||
3677 | EXPORT_SYMBOL(do_SAK); | |
3678 | ||
af9b897e AC |
3679 | /** |
3680 | * flush_to_ldisc | |
65f27f38 | 3681 | * @work: tty structure passed from work queue. |
af9b897e AC |
3682 | * |
3683 | * This routine is called out of the software interrupt to flush data | |
3684 | * from the buffer chain to the line discipline. | |
3685 | * | |
3686 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
3687 | * while invoking the line discipline receive_buf method. The | |
3688 | * receive_buf method is single threaded for each tty instance. | |
1da177e4 | 3689 | */ |
37bdfb07 | 3690 | |
65f27f38 | 3691 | static void flush_to_ldisc(struct work_struct *work) |
1da177e4 | 3692 | { |
65f27f38 DH |
3693 | struct tty_struct *tty = |
3694 | container_of(work, struct tty_struct, buf.work.work); | |
1da177e4 LT |
3695 | unsigned long flags; |
3696 | struct tty_ldisc *disc; | |
2c3bb20f | 3697 | struct tty_buffer *tbuf, *head; |
8977d929 PF |
3698 | char *char_buf; |
3699 | unsigned char *flag_buf; | |
1da177e4 LT |
3700 | |
3701 | disc = tty_ldisc_ref(tty); | |
3702 | if (disc == NULL) /* !TTY_LDISC */ | |
3703 | return; | |
3704 | ||
808249ce | 3705 | spin_lock_irqsave(&tty->buf.lock, flags); |
37bdfb07 AC |
3706 | /* So we know a flush is running */ |
3707 | set_bit(TTY_FLUSHING, &tty->flags); | |
2c3bb20f PF |
3708 | head = tty->buf.head; |
3709 | if (head != NULL) { | |
3710 | tty->buf.head = NULL; | |
3711 | for (;;) { | |
3712 | int count = head->commit - head->read; | |
3713 | if (!count) { | |
3714 | if (head->next == NULL) | |
3715 | break; | |
3716 | tbuf = head; | |
3717 | head = head->next; | |
3718 | tty_buffer_free(tty, tbuf); | |
3719 | continue; | |
3720 | } | |
42fd552e AC |
3721 | /* Ldisc or user is trying to flush the buffers |
3722 | we are feeding to the ldisc, stop feeding the | |
3723 | line discipline as we want to empty the queue */ | |
3724 | if (test_bit(TTY_FLUSHPENDING, &tty->flags)) | |
3725 | break; | |
2c3bb20f PF |
3726 | if (!tty->receive_room) { |
3727 | schedule_delayed_work(&tty->buf.work, 1); | |
3728 | break; | |
3729 | } | |
3730 | if (count > tty->receive_room) | |
3731 | count = tty->receive_room; | |
3732 | char_buf = head->char_buf_ptr + head->read; | |
3733 | flag_buf = head->flag_buf_ptr + head->read; | |
3734 | head->read += count; | |
8977d929 PF |
3735 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3736 | disc->receive_buf(tty, char_buf, flag_buf, count); | |
3737 | spin_lock_irqsave(&tty->buf.lock, flags); | |
3738 | } | |
42fd552e | 3739 | /* Restore the queue head */ |
2c3bb20f | 3740 | tty->buf.head = head; |
33f0f88f | 3741 | } |
42fd552e AC |
3742 | /* We may have a deferred request to flush the input buffer, |
3743 | if so pull the chain under the lock and empty the queue */ | |
3744 | if (test_bit(TTY_FLUSHPENDING, &tty->flags)) { | |
3745 | __tty_buffer_flush(tty); | |
3746 | clear_bit(TTY_FLUSHPENDING, &tty->flags); | |
3747 | wake_up(&tty->read_wait); | |
3748 | } | |
3749 | clear_bit(TTY_FLUSHING, &tty->flags); | |
808249ce | 3750 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
817d6d3b | 3751 | |
1da177e4 LT |
3752 | tty_ldisc_deref(disc); |
3753 | } | |
3754 | ||
1da177e4 LT |
3755 | /** |
3756 | * tty_flip_buffer_push - terminal | |
3757 | * @tty: tty to push | |
3758 | * | |
3759 | * Queue a push of the terminal flip buffers to the line discipline. This | |
3760 | * function must not be called from IRQ context if tty->low_latency is set. | |
3761 | * | |
3762 | * In the event of the queue being busy for flipping the work will be | |
3763 | * held off and retried later. | |
af9b897e AC |
3764 | * |
3765 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
1da177e4 LT |
3766 | */ |
3767 | ||
3768 | void tty_flip_buffer_push(struct tty_struct *tty) | |
3769 | { | |
808249ce PF |
3770 | unsigned long flags; |
3771 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 3772 | if (tty->buf.tail != NULL) |
8977d929 | 3773 | tty->buf.tail->commit = tty->buf.tail->used; |
808249ce PF |
3774 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3775 | ||
1da177e4 | 3776 | if (tty->low_latency) |
65f27f38 | 3777 | flush_to_ldisc(&tty->buf.work.work); |
1da177e4 | 3778 | else |
33f0f88f | 3779 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
3780 | } |
3781 | ||
3782 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
3783 | ||
33f0f88f | 3784 | |
af9b897e AC |
3785 | /** |
3786 | * initialize_tty_struct | |
3787 | * @tty: tty to initialize | |
3788 | * | |
3789 | * This subroutine initializes a tty structure that has been newly | |
3790 | * allocated. | |
3791 | * | |
3792 | * Locking: none - tty in question must not be exposed at this point | |
1da177e4 | 3793 | */ |
af9b897e | 3794 | |
1da177e4 LT |
3795 | static void initialize_tty_struct(struct tty_struct *tty) |
3796 | { | |
3797 | memset(tty, 0, sizeof(struct tty_struct)); | |
3798 | tty->magic = TTY_MAGIC; | |
3799 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
ab521dc0 EB |
3800 | tty->session = NULL; |
3801 | tty->pgrp = NULL; | |
1da177e4 | 3802 | tty->overrun_time = jiffies; |
33f0f88f AC |
3803 | tty->buf.head = tty->buf.tail = NULL; |
3804 | tty_buffer_init(tty); | |
65f27f38 | 3805 | INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); |
5785c95b | 3806 | mutex_init(&tty->termios_mutex); |
1da177e4 LT |
3807 | init_waitqueue_head(&tty->write_wait); |
3808 | init_waitqueue_head(&tty->read_wait); | |
65f27f38 | 3809 | INIT_WORK(&tty->hangup_work, do_tty_hangup); |
70522e12 IM |
3810 | mutex_init(&tty->atomic_read_lock); |
3811 | mutex_init(&tty->atomic_write_lock); | |
1da177e4 | 3812 | spin_lock_init(&tty->read_lock); |
04f378b1 | 3813 | spin_lock_init(&tty->ctrl_lock); |
1da177e4 | 3814 | INIT_LIST_HEAD(&tty->tty_files); |
7f1f86a0 | 3815 | INIT_WORK(&tty->SAK_work, do_SAK_work); |
1da177e4 LT |
3816 | } |
3817 | ||
3818 | /* | |
3819 | * The default put_char routine if the driver did not define one. | |
3820 | */ | |
af9b897e | 3821 | |
1da177e4 LT |
3822 | static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) |
3823 | { | |
3824 | tty->driver->write(tty, &ch, 1); | |
3825 | } | |
3826 | ||
7fe845d1 | 3827 | static struct class *tty_class; |
1da177e4 LT |
3828 | |
3829 | /** | |
af9b897e AC |
3830 | * tty_register_device - register a tty device |
3831 | * @driver: the tty driver that describes the tty device | |
3832 | * @index: the index in the tty driver for this tty device | |
3833 | * @device: a struct device that is associated with this tty device. | |
3834 | * This field is optional, if there is no known struct device | |
3835 | * for this tty device it can be set to NULL safely. | |
1da177e4 | 3836 | * |
01107d34 GKH |
3837 | * Returns a pointer to the struct device for this tty device |
3838 | * (or ERR_PTR(-EFOO) on error). | |
1cdcb6b4 | 3839 | * |
af9b897e AC |
3840 | * This call is required to be made to register an individual tty device |
3841 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
3842 | * that bit is not set, this function should not be called by a tty | |
3843 | * driver. | |
3844 | * | |
3845 | * Locking: ?? | |
1da177e4 | 3846 | */ |
af9b897e | 3847 | |
01107d34 GKH |
3848 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
3849 | struct device *device) | |
1da177e4 LT |
3850 | { |
3851 | char name[64]; | |
3852 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; | |
3853 | ||
3854 | if (index >= driver->num) { | |
3855 | printk(KERN_ERR "Attempt to register invalid tty line number " | |
3856 | " (%d).\n", index); | |
1cdcb6b4 | 3857 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
3858 | } |
3859 | ||
1da177e4 LT |
3860 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
3861 | pty_line_name(driver, index, name); | |
3862 | else | |
3863 | tty_line_name(driver, index, name); | |
1cdcb6b4 | 3864 | |
01107d34 | 3865 | return device_create(tty_class, device, dev, name); |
1da177e4 LT |
3866 | } |
3867 | ||
3868 | /** | |
af9b897e AC |
3869 | * tty_unregister_device - unregister a tty device |
3870 | * @driver: the tty driver that describes the tty device | |
3871 | * @index: the index in the tty driver for this tty device | |
1da177e4 | 3872 | * |
af9b897e AC |
3873 | * If a tty device is registered with a call to tty_register_device() then |
3874 | * this function must be called when the tty device is gone. | |
3875 | * | |
3876 | * Locking: ?? | |
1da177e4 | 3877 | */ |
af9b897e | 3878 | |
1da177e4 LT |
3879 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
3880 | { | |
37bdfb07 AC |
3881 | device_destroy(tty_class, |
3882 | MKDEV(driver->major, driver->minor_start) + index); | |
1da177e4 LT |
3883 | } |
3884 | ||
3885 | EXPORT_SYMBOL(tty_register_device); | |
3886 | EXPORT_SYMBOL(tty_unregister_device); | |
3887 | ||
3888 | struct tty_driver *alloc_tty_driver(int lines) | |
3889 | { | |
3890 | struct tty_driver *driver; | |
3891 | ||
506eb99a | 3892 | driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); |
1da177e4 | 3893 | if (driver) { |
1da177e4 LT |
3894 | driver->magic = TTY_DRIVER_MAGIC; |
3895 | driver->num = lines; | |
3896 | /* later we'll move allocation of tables here */ | |
3897 | } | |
3898 | return driver; | |
3899 | } | |
3900 | ||
3901 | void put_tty_driver(struct tty_driver *driver) | |
3902 | { | |
3903 | kfree(driver); | |
3904 | } | |
3905 | ||
b68e31d0 JD |
3906 | void tty_set_operations(struct tty_driver *driver, |
3907 | const struct tty_operations *op) | |
1da177e4 LT |
3908 | { |
3909 | driver->open = op->open; | |
3910 | driver->close = op->close; | |
3911 | driver->write = op->write; | |
3912 | driver->put_char = op->put_char; | |
3913 | driver->flush_chars = op->flush_chars; | |
3914 | driver->write_room = op->write_room; | |
3915 | driver->chars_in_buffer = op->chars_in_buffer; | |
3916 | driver->ioctl = op->ioctl; | |
e10cc1df | 3917 | driver->compat_ioctl = op->compat_ioctl; |
1da177e4 LT |
3918 | driver->set_termios = op->set_termios; |
3919 | driver->throttle = op->throttle; | |
3920 | driver->unthrottle = op->unthrottle; | |
3921 | driver->stop = op->stop; | |
3922 | driver->start = op->start; | |
3923 | driver->hangup = op->hangup; | |
3924 | driver->break_ctl = op->break_ctl; | |
3925 | driver->flush_buffer = op->flush_buffer; | |
3926 | driver->set_ldisc = op->set_ldisc; | |
3927 | driver->wait_until_sent = op->wait_until_sent; | |
3928 | driver->send_xchar = op->send_xchar; | |
3929 | driver->read_proc = op->read_proc; | |
3930 | driver->write_proc = op->write_proc; | |
3931 | driver->tiocmget = op->tiocmget; | |
3932 | driver->tiocmset = op->tiocmset; | |
f2d937f3 JW |
3933 | #ifdef CONFIG_CONSOLE_POLL |
3934 | driver->poll_init = op->poll_init; | |
3935 | driver->poll_get_char = op->poll_get_char; | |
3936 | driver->poll_put_char = op->poll_put_char; | |
3937 | #endif | |
1da177e4 LT |
3938 | } |
3939 | ||
3940 | ||
3941 | EXPORT_SYMBOL(alloc_tty_driver); | |
3942 | EXPORT_SYMBOL(put_tty_driver); | |
3943 | EXPORT_SYMBOL(tty_set_operations); | |
3944 | ||
3945 | /* | |
3946 | * Called by a tty driver to register itself. | |
3947 | */ | |
3948 | int tty_register_driver(struct tty_driver *driver) | |
3949 | { | |
3950 | int error; | |
37bdfb07 | 3951 | int i; |
1da177e4 LT |
3952 | dev_t dev; |
3953 | void **p = NULL; | |
3954 | ||
3955 | if (driver->flags & TTY_DRIVER_INSTALLED) | |
3956 | return 0; | |
3957 | ||
543691a6 AW |
3958 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { |
3959 | p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); | |
1da177e4 LT |
3960 | if (!p) |
3961 | return -ENOMEM; | |
1da177e4 LT |
3962 | } |
3963 | ||
3964 | if (!driver->major) { | |
37bdfb07 AC |
3965 | error = alloc_chrdev_region(&dev, driver->minor_start, |
3966 | driver->num, driver->name); | |
1da177e4 LT |
3967 | if (!error) { |
3968 | driver->major = MAJOR(dev); | |
3969 | driver->minor_start = MINOR(dev); | |
3970 | } | |
3971 | } else { | |
3972 | dev = MKDEV(driver->major, driver->minor_start); | |
e5717c48 | 3973 | error = register_chrdev_region(dev, driver->num, driver->name); |
1da177e4 LT |
3974 | } |
3975 | if (error < 0) { | |
3976 | kfree(p); | |
3977 | return error; | |
3978 | } | |
3979 | ||
3980 | if (p) { | |
3981 | driver->ttys = (struct tty_struct **)p; | |
edc6afc5 | 3982 | driver->termios = (struct ktermios **)(p + driver->num); |
37bdfb07 AC |
3983 | driver->termios_locked = (struct ktermios **) |
3984 | (p + driver->num * 2); | |
1da177e4 LT |
3985 | } else { |
3986 | driver->ttys = NULL; | |
3987 | driver->termios = NULL; | |
3988 | driver->termios_locked = NULL; | |
3989 | } | |
3990 | ||
3991 | cdev_init(&driver->cdev, &tty_fops); | |
3992 | driver->cdev.owner = driver->owner; | |
3993 | error = cdev_add(&driver->cdev, dev, driver->num); | |
3994 | if (error) { | |
1da177e4 LT |
3995 | unregister_chrdev_region(dev, driver->num); |
3996 | driver->ttys = NULL; | |
3997 | driver->termios = driver->termios_locked = NULL; | |
3998 | kfree(p); | |
3999 | return error; | |
4000 | } | |
4001 | ||
4002 | if (!driver->put_char) | |
4003 | driver->put_char = tty_default_put_char; | |
37bdfb07 | 4004 | |
ca509f69 | 4005 | mutex_lock(&tty_mutex); |
1da177e4 | 4006 | list_add(&driver->tty_drivers, &tty_drivers); |
ca509f69 | 4007 | mutex_unlock(&tty_mutex); |
37bdfb07 AC |
4008 | |
4009 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { | |
4010 | for (i = 0; i < driver->num; i++) | |
1da177e4 LT |
4011 | tty_register_device(driver, i, NULL); |
4012 | } | |
4013 | proc_tty_register_driver(driver); | |
4014 | return 0; | |
4015 | } | |
4016 | ||
4017 | EXPORT_SYMBOL(tty_register_driver); | |
4018 | ||
4019 | /* | |
4020 | * Called by a tty driver to unregister itself. | |
4021 | */ | |
4022 | int tty_unregister_driver(struct tty_driver *driver) | |
4023 | { | |
4024 | int i; | |
edc6afc5 | 4025 | struct ktermios *tp; |
1da177e4 LT |
4026 | void *p; |
4027 | ||
4028 | if (driver->refcount) | |
4029 | return -EBUSY; | |
4030 | ||
4031 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
4032 | driver->num); | |
ca509f69 | 4033 | mutex_lock(&tty_mutex); |
1da177e4 | 4034 | list_del(&driver->tty_drivers); |
ca509f69 | 4035 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
4036 | |
4037 | /* | |
4038 | * Free the termios and termios_locked structures because | |
4039 | * we don't want to get memory leaks when modular tty | |
4040 | * drivers are removed from the kernel. | |
4041 | */ | |
4042 | for (i = 0; i < driver->num; i++) { | |
4043 | tp = driver->termios[i]; | |
4044 | if (tp) { | |
4045 | driver->termios[i] = NULL; | |
4046 | kfree(tp); | |
4047 | } | |
4048 | tp = driver->termios_locked[i]; | |
4049 | if (tp) { | |
4050 | driver->termios_locked[i] = NULL; | |
4051 | kfree(tp); | |
4052 | } | |
331b8319 | 4053 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
1da177e4 LT |
4054 | tty_unregister_device(driver, i); |
4055 | } | |
4056 | p = driver->ttys; | |
4057 | proc_tty_unregister_driver(driver); | |
4058 | driver->ttys = NULL; | |
4059 | driver->termios = driver->termios_locked = NULL; | |
4060 | kfree(p); | |
4061 | cdev_del(&driver->cdev); | |
4062 | return 0; | |
4063 | } | |
1da177e4 LT |
4064 | EXPORT_SYMBOL(tty_unregister_driver); |
4065 | ||
24ec839c PZ |
4066 | dev_t tty_devnum(struct tty_struct *tty) |
4067 | { | |
4068 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
4069 | } | |
4070 | EXPORT_SYMBOL(tty_devnum); | |
4071 | ||
4072 | void proc_clear_tty(struct task_struct *p) | |
4073 | { | |
4074 | spin_lock_irq(&p->sighand->siglock); | |
4075 | p->signal->tty = NULL; | |
4076 | spin_unlock_irq(&p->sighand->siglock); | |
4077 | } | |
7cac4ce5 | 4078 | EXPORT_SYMBOL(proc_clear_tty); |
24ec839c | 4079 | |
2a65f1d9 | 4080 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
4081 | { |
4082 | if (tty) { | |
d9c1e9a8 EB |
4083 | /* We should not have a session or pgrp to here but.... */ |
4084 | put_pid(tty->session); | |
4085 | put_pid(tty->pgrp); | |
ab521dc0 EB |
4086 | tty->session = get_pid(task_session(tsk)); |
4087 | tty->pgrp = get_pid(task_pgrp(tsk)); | |
24ec839c | 4088 | } |
2a65f1d9 | 4089 | put_pid(tsk->signal->tty_old_pgrp); |
24ec839c | 4090 | tsk->signal->tty = tty; |
ab521dc0 | 4091 | tsk->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
4092 | } |
4093 | ||
98a27ba4 | 4094 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
4095 | { |
4096 | spin_lock_irq(&tsk->sighand->siglock); | |
2a65f1d9 | 4097 | __proc_set_tty(tsk, tty); |
24ec839c PZ |
4098 | spin_unlock_irq(&tsk->sighand->siglock); |
4099 | } | |
4100 | ||
4101 | struct tty_struct *get_current_tty(void) | |
4102 | { | |
4103 | struct tty_struct *tty; | |
4104 | WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); | |
4105 | tty = current->signal->tty; | |
4106 | /* | |
4107 | * session->tty can be changed/cleared from under us, make sure we | |
4108 | * issue the load. The obtained pointer, when not NULL, is valid as | |
4109 | * long as we hold tty_mutex. | |
4110 | */ | |
4111 | barrier(); | |
4112 | return tty; | |
4113 | } | |
a311f743 | 4114 | EXPORT_SYMBOL_GPL(get_current_tty); |
1da177e4 LT |
4115 | |
4116 | /* | |
4117 | * Initialize the console device. This is called *early*, so | |
4118 | * we can't necessarily depend on lots of kernel help here. | |
4119 | * Just do some early initializations, and do the complex setup | |
4120 | * later. | |
4121 | */ | |
4122 | void __init console_init(void) | |
4123 | { | |
4124 | initcall_t *call; | |
4125 | ||
4126 | /* Setup the default TTY line discipline. */ | |
4127 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); | |
4128 | ||
4129 | /* | |
37bdfb07 | 4130 | * set up the console device so that later boot sequences can |
1da177e4 LT |
4131 | * inform about problems etc.. |
4132 | */ | |
1da177e4 LT |
4133 | call = __con_initcall_start; |
4134 | while (call < __con_initcall_end) { | |
4135 | (*call)(); | |
4136 | call++; | |
4137 | } | |
4138 | } | |
4139 | ||
1da177e4 LT |
4140 | static int __init tty_class_init(void) |
4141 | { | |
7fe845d1 | 4142 | tty_class = class_create(THIS_MODULE, "tty"); |
1da177e4 LT |
4143 | if (IS_ERR(tty_class)) |
4144 | return PTR_ERR(tty_class); | |
4145 | return 0; | |
4146 | } | |
4147 | ||
4148 | postcore_initcall(tty_class_init); | |
4149 | ||
4150 | /* 3/2004 jmc: why do these devices exist? */ | |
4151 | ||
4152 | static struct cdev tty_cdev, console_cdev; | |
4153 | #ifdef CONFIG_UNIX98_PTYS | |
4154 | static struct cdev ptmx_cdev; | |
4155 | #endif | |
4156 | #ifdef CONFIG_VT | |
4157 | static struct cdev vc0_cdev; | |
4158 | #endif | |
4159 | ||
4160 | /* | |
4161 | * Ok, now we can initialize the rest of the tty devices and can count | |
4162 | * on memory allocations, interrupts etc.. | |
4163 | */ | |
4164 | static int __init tty_init(void) | |
4165 | { | |
4166 | cdev_init(&tty_cdev, &tty_fops); | |
4167 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
4168 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
4169 | panic("Couldn't register /dev/tty driver\n"); | |
01107d34 | 4170 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty"); |
1da177e4 LT |
4171 | |
4172 | cdev_init(&console_cdev, &console_fops); | |
4173 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
4174 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
4175 | panic("Couldn't register /dev/console driver\n"); | |
01107d34 | 4176 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console"); |
1da177e4 LT |
4177 | |
4178 | #ifdef CONFIG_UNIX98_PTYS | |
4179 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
4180 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
4181 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
4182 | panic("Couldn't register /dev/ptmx driver\n"); | |
01107d34 | 4183 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); |
1da177e4 LT |
4184 | #endif |
4185 | ||
4186 | #ifdef CONFIG_VT | |
4187 | cdev_init(&vc0_cdev, &console_fops); | |
4188 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || | |
4189 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) | |
4190 | panic("Couldn't register /dev/tty0 driver\n"); | |
01107d34 | 4191 | device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); |
1da177e4 LT |
4192 | |
4193 | vty_init(); | |
4194 | #endif | |
4195 | return 0; | |
4196 | } | |
4197 | module_init(tty_init); |