Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/drivers/char/tty_io.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles | |
9 | * or rs-channels. It also implements echoing, cooked mode etc. | |
10 | * | |
11 | * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. | |
12 | * | |
13 | * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the | |
14 | * tty_struct and tty_queue structures. Previously there was an array | |
15 | * of 256 tty_struct's which was statically allocated, and the | |
16 | * tty_queue structures were allocated at boot time. Both are now | |
17 | * dynamically allocated only when the tty is open. | |
18 | * | |
19 | * Also restructured routines so that there is more of a separation | |
20 | * between the high-level tty routines (tty_io.c and tty_ioctl.c) and | |
21 | * the low-level tty routines (serial.c, pty.c, console.c). This | |
37bdfb07 | 22 | * makes for cleaner and more compact code. -TYT, 9/17/92 |
1da177e4 LT |
23 | * |
24 | * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines | |
25 | * which can be dynamically activated and de-activated by the line | |
26 | * discipline handling modules (like SLIP). | |
27 | * | |
28 | * NOTE: pay no attention to the line discipline code (yet); its | |
29 | * interface is still subject to change in this version... | |
30 | * -- TYT, 1/31/92 | |
31 | * | |
32 | * Added functionality to the OPOST tty handling. No delays, but all | |
33 | * other bits should be there. | |
34 | * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. | |
35 | * | |
36 | * Rewrote canonical mode and added more termios flags. | |
37 | * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 | |
38 | * | |
39 | * Reorganized FASYNC support so mouse code can share it. | |
40 | * -- ctm@ardi.com, 9Sep95 | |
41 | * | |
42 | * New TIOCLINUX variants added. | |
43 | * -- mj@k332.feld.cvut.cz, 19-Nov-95 | |
37bdfb07 | 44 | * |
1da177e4 LT |
45 | * Restrict vt switching via ioctl() |
46 | * -- grif@cs.ucr.edu, 5-Dec-95 | |
47 | * | |
48 | * Move console and virtual terminal code to more appropriate files, | |
49 | * implement CONFIG_VT and generalize console device interface. | |
50 | * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 | |
51 | * | |
52 | * Rewrote init_dev and release_dev to eliminate races. | |
53 | * -- Bill Hawes <whawes@star.net>, June 97 | |
54 | * | |
55 | * Added devfs support. | |
56 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 | |
57 | * | |
58 | * Added support for a Unix98-style ptmx device. | |
59 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 | |
60 | * | |
61 | * Reduced memory usage for older ARM systems | |
62 | * -- Russell King <rmk@arm.linux.org.uk> | |
63 | * | |
64 | * Move do_SAK() into process context. Less stack use in devfs functions. | |
37bdfb07 AC |
65 | * alloc_tty_struct() always uses kmalloc() |
66 | * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 | |
1da177e4 LT |
67 | */ |
68 | ||
1da177e4 LT |
69 | #include <linux/types.h> |
70 | #include <linux/major.h> | |
71 | #include <linux/errno.h> | |
72 | #include <linux/signal.h> | |
73 | #include <linux/fcntl.h> | |
74 | #include <linux/sched.h> | |
75 | #include <linux/interrupt.h> | |
76 | #include <linux/tty.h> | |
77 | #include <linux/tty_driver.h> | |
78 | #include <linux/tty_flip.h> | |
79 | #include <linux/devpts_fs.h> | |
80 | #include <linux/file.h> | |
9f3acc31 | 81 | #include <linux/fdtable.h> |
1da177e4 LT |
82 | #include <linux/console.h> |
83 | #include <linux/timer.h> | |
84 | #include <linux/ctype.h> | |
85 | #include <linux/kd.h> | |
86 | #include <linux/mm.h> | |
87 | #include <linux/string.h> | |
88 | #include <linux/slab.h> | |
89 | #include <linux/poll.h> | |
90 | #include <linux/proc_fs.h> | |
91 | #include <linux/init.h> | |
92 | #include <linux/module.h> | |
93 | #include <linux/smp_lock.h> | |
94 | #include <linux/device.h> | |
1da177e4 LT |
95 | #include <linux/wait.h> |
96 | #include <linux/bitops.h> | |
b20f3ae5 | 97 | #include <linux/delay.h> |
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 */ | |
1da177e4 LT |
140 | static int ptmx_open(struct inode *, struct file *); |
141 | #endif | |
142 | ||
1da177e4 LT |
143 | static void initialize_tty_struct(struct tty_struct *tty); |
144 | ||
145 | static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); | |
146 | static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); | |
37bdfb07 AC |
147 | ssize_t redirected_tty_write(struct file *, const char __user *, |
148 | size_t, loff_t *); | |
1da177e4 LT |
149 | static unsigned int tty_poll(struct file *, poll_table *); |
150 | static int tty_open(struct inode *, struct file *); | |
151 | static int tty_release(struct inode *, struct file *); | |
04f378b1 | 152 | long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg); |
e10cc1df | 153 | #ifdef CONFIG_COMPAT |
37bdfb07 | 154 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
e10cc1df PF |
155 | unsigned long arg); |
156 | #else | |
157 | #define tty_compat_ioctl NULL | |
158 | #endif | |
37bdfb07 | 159 | static int tty_fasync(int fd, struct file *filp, int on); |
d5698c28 | 160 | static void release_tty(struct tty_struct *tty, int idx); |
2a65f1d9 | 161 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
98a27ba4 | 162 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty); |
1da177e4 | 163 | |
af9b897e AC |
164 | /** |
165 | * alloc_tty_struct - allocate a tty object | |
166 | * | |
167 | * Return a new empty tty structure. The data fields have not | |
168 | * been initialized in any way but has been zeroed | |
169 | * | |
170 | * Locking: none | |
af9b897e | 171 | */ |
1da177e4 LT |
172 | |
173 | static struct tty_struct *alloc_tty_struct(void) | |
174 | { | |
1266b1e1 | 175 | return kzalloc(sizeof(struct tty_struct), GFP_KERNEL); |
1da177e4 LT |
176 | } |
177 | ||
33f0f88f AC |
178 | static void tty_buffer_free_all(struct tty_struct *); |
179 | ||
af9b897e AC |
180 | /** |
181 | * free_tty_struct - free a disused tty | |
182 | * @tty: tty struct to free | |
183 | * | |
184 | * Free the write buffers, tty queue and tty memory itself. | |
185 | * | |
186 | * Locking: none. Must be called after tty is definitely unused | |
187 | */ | |
188 | ||
1da177e4 LT |
189 | static inline void free_tty_struct(struct tty_struct *tty) |
190 | { | |
191 | kfree(tty->write_buf); | |
33f0f88f | 192 | tty_buffer_free_all(tty); |
1da177e4 LT |
193 | kfree(tty); |
194 | } | |
195 | ||
196 | #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) | |
197 | ||
af9b897e AC |
198 | /** |
199 | * tty_name - return tty naming | |
200 | * @tty: tty structure | |
201 | * @buf: buffer for output | |
202 | * | |
203 | * Convert a tty structure into a name. The name reflects the kernel | |
204 | * naming policy and if udev is in use may not reflect user space | |
205 | * | |
206 | * Locking: none | |
207 | */ | |
208 | ||
1da177e4 LT |
209 | char *tty_name(struct tty_struct *tty, char *buf) |
210 | { | |
211 | if (!tty) /* Hmm. NULL pointer. That's fun. */ | |
212 | strcpy(buf, "NULL tty"); | |
213 | else | |
214 | strcpy(buf, tty->name); | |
215 | return buf; | |
216 | } | |
217 | ||
218 | EXPORT_SYMBOL(tty_name); | |
219 | ||
d769a669 | 220 | int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, |
1da177e4 LT |
221 | const char *routine) |
222 | { | |
223 | #ifdef TTY_PARANOIA_CHECK | |
224 | if (!tty) { | |
225 | printk(KERN_WARNING | |
226 | "null TTY for (%d:%d) in %s\n", | |
227 | imajor(inode), iminor(inode), routine); | |
228 | return 1; | |
229 | } | |
230 | if (tty->magic != TTY_MAGIC) { | |
231 | printk(KERN_WARNING | |
232 | "bad magic number for tty struct (%d:%d) in %s\n", | |
233 | imajor(inode), iminor(inode), routine); | |
234 | return 1; | |
235 | } | |
236 | #endif | |
237 | return 0; | |
238 | } | |
239 | ||
240 | static int check_tty_count(struct tty_struct *tty, const char *routine) | |
241 | { | |
242 | #ifdef CHECK_TTY_COUNT | |
243 | struct list_head *p; | |
244 | int count = 0; | |
37bdfb07 | 245 | |
1da177e4 LT |
246 | file_list_lock(); |
247 | list_for_each(p, &tty->tty_files) { | |
248 | count++; | |
249 | } | |
250 | file_list_unlock(); | |
251 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
252 | tty->driver->subtype == PTY_TYPE_SLAVE && | |
253 | tty->link && tty->link->count) | |
254 | count++; | |
255 | if (tty->count != count) { | |
256 | printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " | |
257 | "!= #fd's(%d) in %s\n", | |
258 | tty->name, tty->count, count, routine); | |
259 | return count; | |
24ec839c | 260 | } |
1da177e4 LT |
261 | #endif |
262 | return 0; | |
263 | } | |
264 | ||
33f0f88f AC |
265 | /* |
266 | * Tty buffer allocation management | |
267 | */ | |
268 | ||
af9b897e AC |
269 | /** |
270 | * tty_buffer_free_all - free buffers used by a tty | |
271 | * @tty: tty to free from | |
272 | * | |
273 | * Remove all the buffers pending on a tty whether queued with data | |
274 | * or in the free ring. Must be called when the tty is no longer in use | |
275 | * | |
276 | * Locking: none | |
277 | */ | |
278 | ||
33f0f88f AC |
279 | static void tty_buffer_free_all(struct tty_struct *tty) |
280 | { | |
281 | struct tty_buffer *thead; | |
37bdfb07 | 282 | while ((thead = tty->buf.head) != NULL) { |
33f0f88f AC |
283 | tty->buf.head = thead->next; |
284 | kfree(thead); | |
285 | } | |
37bdfb07 | 286 | while ((thead = tty->buf.free) != NULL) { |
33f0f88f AC |
287 | tty->buf.free = thead->next; |
288 | kfree(thead); | |
289 | } | |
290 | tty->buf.tail = NULL; | |
01da5fd8 | 291 | tty->buf.memory_used = 0; |
33f0f88f AC |
292 | } |
293 | ||
01da5fd8 AC |
294 | /** |
295 | * tty_buffer_init - prepare a tty buffer structure | |
296 | * @tty: tty to initialise | |
297 | * | |
298 | * Set up the initial state of the buffer management for a tty device. | |
299 | * Must be called before the other tty buffer functions are used. | |
300 | * | |
301 | * Locking: none | |
302 | */ | |
303 | ||
33f0f88f AC |
304 | static void tty_buffer_init(struct tty_struct *tty) |
305 | { | |
808249ce | 306 | spin_lock_init(&tty->buf.lock); |
33f0f88f AC |
307 | tty->buf.head = NULL; |
308 | tty->buf.tail = NULL; | |
309 | tty->buf.free = NULL; | |
01da5fd8 | 310 | tty->buf.memory_used = 0; |
33f0f88f AC |
311 | } |
312 | ||
01da5fd8 AC |
313 | /** |
314 | * tty_buffer_alloc - allocate a tty buffer | |
315 | * @tty: tty device | |
316 | * @size: desired size (characters) | |
317 | * | |
318 | * Allocate a new tty buffer to hold the desired number of characters. | |
319 | * Return NULL if out of memory or the allocation would exceed the | |
320 | * per device queue | |
321 | * | |
322 | * Locking: Caller must hold tty->buf.lock | |
323 | */ | |
324 | ||
325 | static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) | |
33f0f88f | 326 | { |
01da5fd8 AC |
327 | struct tty_buffer *p; |
328 | ||
329 | if (tty->buf.memory_used + size > 65536) | |
330 | return NULL; | |
331 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); | |
37bdfb07 | 332 | if (p == NULL) |
33f0f88f AC |
333 | return NULL; |
334 | p->used = 0; | |
335 | p->size = size; | |
336 | p->next = NULL; | |
8977d929 PF |
337 | p->commit = 0; |
338 | p->read = 0; | |
33f0f88f AC |
339 | p->char_buf_ptr = (char *)(p->data); |
340 | p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; | |
01da5fd8 | 341 | tty->buf.memory_used += size; |
33f0f88f AC |
342 | return p; |
343 | } | |
344 | ||
01da5fd8 AC |
345 | /** |
346 | * tty_buffer_free - free a tty buffer | |
347 | * @tty: tty owning the buffer | |
348 | * @b: the buffer to free | |
349 | * | |
350 | * Free a tty buffer, or add it to the free list according to our | |
351 | * internal strategy | |
352 | * | |
353 | * Locking: Caller must hold tty->buf.lock | |
354 | */ | |
33f0f88f AC |
355 | |
356 | static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) | |
357 | { | |
358 | /* Dumb strategy for now - should keep some stats */ | |
01da5fd8 AC |
359 | tty->buf.memory_used -= b->size; |
360 | WARN_ON(tty->buf.memory_used < 0); | |
361 | ||
37bdfb07 | 362 | if (b->size >= 512) |
33f0f88f AC |
363 | kfree(b); |
364 | else { | |
365 | b->next = tty->buf.free; | |
366 | tty->buf.free = b; | |
367 | } | |
368 | } | |
369 | ||
c5c34d48 | 370 | /** |
42fd552e | 371 | * __tty_buffer_flush - flush full tty buffers |
c5c34d48 PF |
372 | * @tty: tty to flush |
373 | * | |
42fd552e AC |
374 | * flush all the buffers containing receive data. Caller must |
375 | * hold the buffer lock and must have ensured no parallel flush to | |
376 | * ldisc is running. | |
c5c34d48 | 377 | * |
42fd552e | 378 | * Locking: Caller must hold tty->buf.lock |
c5c34d48 PF |
379 | */ |
380 | ||
42fd552e | 381 | static void __tty_buffer_flush(struct tty_struct *tty) |
c5c34d48 PF |
382 | { |
383 | struct tty_buffer *thead; | |
c5c34d48 | 384 | |
37bdfb07 | 385 | while ((thead = tty->buf.head) != NULL) { |
c5c34d48 PF |
386 | tty->buf.head = thead->next; |
387 | tty_buffer_free(tty, thead); | |
388 | } | |
389 | tty->buf.tail = NULL; | |
42fd552e AC |
390 | } |
391 | ||
392 | /** | |
393 | * tty_buffer_flush - flush full tty buffers | |
394 | * @tty: tty to flush | |
395 | * | |
396 | * flush all the buffers containing receive data. If the buffer is | |
397 | * being processed by flush_to_ldisc then we defer the processing | |
398 | * to that function | |
399 | * | |
400 | * Locking: none | |
401 | */ | |
402 | ||
403 | static void tty_buffer_flush(struct tty_struct *tty) | |
404 | { | |
405 | unsigned long flags; | |
406 | spin_lock_irqsave(&tty->buf.lock, flags); | |
407 | ||
408 | /* If the data is being pushed to the tty layer then we can't | |
409 | process it here. Instead set a flag and the flush_to_ldisc | |
410 | path will process the flush request before it exits */ | |
411 | if (test_bit(TTY_FLUSHING, &tty->flags)) { | |
412 | set_bit(TTY_FLUSHPENDING, &tty->flags); | |
413 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
414 | wait_event(tty->read_wait, | |
415 | test_bit(TTY_FLUSHPENDING, &tty->flags) == 0); | |
416 | return; | |
417 | } else | |
418 | __tty_buffer_flush(tty); | |
c5c34d48 PF |
419 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
420 | } | |
421 | ||
01da5fd8 AC |
422 | /** |
423 | * tty_buffer_find - find a free tty buffer | |
424 | * @tty: tty owning the buffer | |
425 | * @size: characters wanted | |
426 | * | |
427 | * Locate an existing suitable tty buffer or if we are lacking one then | |
428 | * allocate a new one. We round our buffers off in 256 character chunks | |
429 | * to get better allocation behaviour. | |
430 | * | |
431 | * Locking: Caller must hold tty->buf.lock | |
432 | */ | |
433 | ||
33f0f88f AC |
434 | static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) |
435 | { | |
436 | struct tty_buffer **tbh = &tty->buf.free; | |
37bdfb07 | 437 | while ((*tbh) != NULL) { |
33f0f88f | 438 | struct tty_buffer *t = *tbh; |
37bdfb07 | 439 | if (t->size >= size) { |
33f0f88f AC |
440 | *tbh = t->next; |
441 | t->next = NULL; | |
442 | t->used = 0; | |
8977d929 PF |
443 | t->commit = 0; |
444 | t->read = 0; | |
01da5fd8 | 445 | tty->buf.memory_used += t->size; |
33f0f88f AC |
446 | return t; |
447 | } | |
448 | tbh = &((*tbh)->next); | |
449 | } | |
450 | /* Round the buffer size out */ | |
37bdfb07 | 451 | size = (size + 0xFF) & ~0xFF; |
01da5fd8 | 452 | return tty_buffer_alloc(tty, size); |
33f0f88f AC |
453 | /* Should possibly check if this fails for the largest buffer we |
454 | have queued and recycle that ? */ | |
455 | } | |
456 | ||
01da5fd8 AC |
457 | /** |
458 | * tty_buffer_request_room - grow tty buffer if needed | |
459 | * @tty: tty structure | |
460 | * @size: size desired | |
461 | * | |
462 | * Make at least size bytes of linear space available for the tty | |
463 | * buffer. If we fail return the size we managed to find. | |
464 | * | |
465 | * Locking: Takes tty->buf.lock | |
466 | */ | |
33f0f88f AC |
467 | int tty_buffer_request_room(struct tty_struct *tty, size_t size) |
468 | { | |
808249ce PF |
469 | struct tty_buffer *b, *n; |
470 | int left; | |
471 | unsigned long flags; | |
472 | ||
473 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33f0f88f AC |
474 | |
475 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to | |
476 | remove this conditional if its worth it. This would be invisible | |
477 | to the callers */ | |
33b37a33 | 478 | if ((b = tty->buf.tail) != NULL) |
33f0f88f | 479 | left = b->size - b->used; |
33b37a33 | 480 | else |
808249ce PF |
481 | left = 0; |
482 | ||
483 | if (left < size) { | |
484 | /* This is the slow path - looking for new buffers to use */ | |
485 | if ((n = tty_buffer_find(tty, size)) != NULL) { | |
486 | if (b != NULL) { | |
487 | b->next = n; | |
8977d929 | 488 | b->commit = b->used; |
808249ce PF |
489 | } else |
490 | tty->buf.head = n; | |
491 | tty->buf.tail = n; | |
808249ce PF |
492 | } else |
493 | size = left; | |
494 | } | |
495 | ||
496 | spin_unlock_irqrestore(&tty->buf.lock, flags); | |
33f0f88f AC |
497 | return size; |
498 | } | |
33f0f88f AC |
499 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
500 | ||
af9b897e AC |
501 | /** |
502 | * tty_insert_flip_string - Add characters to the tty buffer | |
503 | * @tty: tty structure | |
504 | * @chars: characters | |
505 | * @size: size | |
506 | * | |
507 | * Queue a series of bytes to the tty buffering. All the characters | |
508 | * passed are marked as without error. Returns the number added. | |
509 | * | |
510 | * Locking: Called functions may take tty->buf.lock | |
511 | */ | |
512 | ||
e1a25090 AM |
513 | int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, |
514 | size_t size) | |
33f0f88f AC |
515 | { |
516 | int copied = 0; | |
517 | do { | |
518 | int space = tty_buffer_request_room(tty, size - copied); | |
519 | struct tty_buffer *tb = tty->buf.tail; | |
520 | /* If there is no space then tb may be NULL */ | |
37bdfb07 | 521 | if (unlikely(space == 0)) |
33f0f88f AC |
522 | break; |
523 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
524 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
525 | tb->used += space; | |
526 | copied += space; | |
527 | chars += space; | |
527063ba AD |
528 | /* There is a small chance that we need to split the data over |
529 | several buffers. If this is the case we must loop */ | |
530 | } while (unlikely(size > copied)); | |
33f0f88f AC |
531 | return copied; |
532 | } | |
ee37df78 | 533 | EXPORT_SYMBOL(tty_insert_flip_string); |
33f0f88f | 534 | |
af9b897e AC |
535 | /** |
536 | * tty_insert_flip_string_flags - Add characters to the tty buffer | |
537 | * @tty: tty structure | |
538 | * @chars: characters | |
539 | * @flags: flag bytes | |
540 | * @size: size | |
541 | * | |
542 | * Queue a series of bytes to the tty buffering. For each character | |
543 | * the flags array indicates the status of the character. Returns the | |
544 | * number added. | |
545 | * | |
546 | * Locking: Called functions may take tty->buf.lock | |
547 | */ | |
548 | ||
e1a25090 AM |
549 | int tty_insert_flip_string_flags(struct tty_struct *tty, |
550 | const unsigned char *chars, const char *flags, size_t size) | |
33f0f88f AC |
551 | { |
552 | int copied = 0; | |
553 | do { | |
554 | int space = tty_buffer_request_room(tty, size - copied); | |
555 | struct tty_buffer *tb = tty->buf.tail; | |
556 | /* If there is no space then tb may be NULL */ | |
37bdfb07 | 557 | if (unlikely(space == 0)) |
33f0f88f AC |
558 | break; |
559 | memcpy(tb->char_buf_ptr + tb->used, chars, space); | |
560 | memcpy(tb->flag_buf_ptr + tb->used, flags, space); | |
561 | tb->used += space; | |
562 | copied += space; | |
563 | chars += space; | |
564 | flags += space; | |
527063ba AD |
565 | /* There is a small chance that we need to split the data over |
566 | several buffers. If this is the case we must loop */ | |
567 | } while (unlikely(size > copied)); | |
33f0f88f AC |
568 | return copied; |
569 | } | |
ff4547f4 | 570 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
33f0f88f | 571 | |
af9b897e AC |
572 | /** |
573 | * tty_schedule_flip - push characters to ldisc | |
574 | * @tty: tty to push from | |
575 | * | |
576 | * Takes any pending buffers and transfers their ownership to the | |
577 | * ldisc side of the queue. It then schedules those characters for | |
578 | * processing by the line discipline. | |
579 | * | |
580 | * Locking: Takes tty->buf.lock | |
581 | */ | |
582 | ||
e1a25090 AM |
583 | void tty_schedule_flip(struct tty_struct *tty) |
584 | { | |
585 | unsigned long flags; | |
586 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 587 | if (tty->buf.tail != NULL) |
e1a25090 | 588 | tty->buf.tail->commit = tty->buf.tail->used; |
e1a25090 AM |
589 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
590 | schedule_delayed_work(&tty->buf.work, 1); | |
591 | } | |
592 | EXPORT_SYMBOL(tty_schedule_flip); | |
33f0f88f | 593 | |
af9b897e AC |
594 | /** |
595 | * tty_prepare_flip_string - make room for characters | |
596 | * @tty: tty | |
597 | * @chars: return pointer for character write area | |
598 | * @size: desired size | |
599 | * | |
33f0f88f AC |
600 | * Prepare a block of space in the buffer for data. Returns the length |
601 | * available and buffer pointer to the space which is now allocated and | |
602 | * accounted for as ready for normal characters. This is used for drivers | |
603 | * that need their own block copy routines into the buffer. There is no | |
604 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
605 | * |
606 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
607 | */ |
608 | ||
37bdfb07 AC |
609 | int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, |
610 | size_t size) | |
33f0f88f AC |
611 | { |
612 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
613 | if (likely(space)) { |
614 | struct tty_buffer *tb = tty->buf.tail; | |
615 | *chars = tb->char_buf_ptr + tb->used; | |
616 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); | |
617 | tb->used += space; | |
618 | } | |
33f0f88f AC |
619 | return space; |
620 | } | |
621 | ||
622 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); | |
623 | ||
af9b897e AC |
624 | /** |
625 | * tty_prepare_flip_string_flags - make room for characters | |
626 | * @tty: tty | |
627 | * @chars: return pointer for character write area | |
628 | * @flags: return pointer for status flag write area | |
629 | * @size: desired size | |
630 | * | |
33f0f88f AC |
631 | * Prepare a block of space in the buffer for data. Returns the length |
632 | * available and buffer pointer to the space which is now allocated and | |
633 | * accounted for as ready for characters. This is used for drivers | |
634 | * that need their own block copy routines into the buffer. There is no | |
635 | * guarantee the buffer is a DMA target! | |
af9b897e AC |
636 | * |
637 | * Locking: May call functions taking tty->buf.lock | |
33f0f88f AC |
638 | */ |
639 | ||
37bdfb07 AC |
640 | int tty_prepare_flip_string_flags(struct tty_struct *tty, |
641 | unsigned char **chars, char **flags, size_t size) | |
33f0f88f AC |
642 | { |
643 | int space = tty_buffer_request_room(tty, size); | |
808249ce PF |
644 | if (likely(space)) { |
645 | struct tty_buffer *tb = tty->buf.tail; | |
646 | *chars = tb->char_buf_ptr + tb->used; | |
647 | *flags = tb->flag_buf_ptr + tb->used; | |
648 | tb->used += space; | |
649 | } | |
33f0f88f AC |
650 | return space; |
651 | } | |
652 | ||
653 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); | |
654 | ||
655 | ||
656 | ||
af9b897e AC |
657 | /** |
658 | * tty_set_termios_ldisc - set ldisc field | |
659 | * @tty: tty structure | |
660 | * @num: line discipline number | |
661 | * | |
1da177e4 | 662 | * This is probably overkill for real world processors but |
37bdfb07 | 663 | * they are not on hot paths so a little discipline won't do |
1da177e4 | 664 | * any harm. |
af9b897e | 665 | * |
24ec839c | 666 | * Locking: takes termios_mutex |
1da177e4 | 667 | */ |
37bdfb07 | 668 | |
1da177e4 LT |
669 | static void tty_set_termios_ldisc(struct tty_struct *tty, int num) |
670 | { | |
5785c95b | 671 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 672 | tty->termios->c_line = num; |
5785c95b | 673 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
674 | } |
675 | ||
676 | /* | |
677 | * This guards the refcounted line discipline lists. The lock | |
678 | * must be taken with irqs off because there are hangup path | |
679 | * callers who will do ldisc lookups and cannot sleep. | |
680 | */ | |
37bdfb07 | 681 | |
1da177e4 LT |
682 | static DEFINE_SPINLOCK(tty_ldisc_lock); |
683 | static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); | |
37bdfb07 AC |
684 | /* Line disc dispatch table */ |
685 | static struct tty_ldisc tty_ldiscs[NR_LDISCS]; | |
1da177e4 | 686 | |
af9b897e AC |
687 | /** |
688 | * tty_register_ldisc - install a line discipline | |
689 | * @disc: ldisc number | |
690 | * @new_ldisc: pointer to the ldisc object | |
691 | * | |
692 | * Installs a new line discipline into the kernel. The discipline | |
693 | * is set up as unreferenced and then made available to the kernel | |
694 | * from this point onwards. | |
695 | * | |
696 | * Locking: | |
697 | * takes tty_ldisc_lock to guard against ldisc races | |
698 | */ | |
699 | ||
1da177e4 LT |
700 | int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) |
701 | { | |
702 | unsigned long flags; | |
703 | int ret = 0; | |
37bdfb07 | 704 | |
1da177e4 LT |
705 | if (disc < N_TTY || disc >= NR_LDISCS) |
706 | return -EINVAL; | |
37bdfb07 | 707 | |
1da177e4 | 708 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
bfb07599 AD |
709 | tty_ldiscs[disc] = *new_ldisc; |
710 | tty_ldiscs[disc].num = disc; | |
711 | tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; | |
712 | tty_ldiscs[disc].refcount = 0; | |
1da177e4 | 713 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
37bdfb07 | 714 | |
1da177e4 LT |
715 | return ret; |
716 | } | |
1da177e4 LT |
717 | EXPORT_SYMBOL(tty_register_ldisc); |
718 | ||
af9b897e AC |
719 | /** |
720 | * tty_unregister_ldisc - unload a line discipline | |
721 | * @disc: ldisc number | |
722 | * @new_ldisc: pointer to the ldisc object | |
723 | * | |
724 | * Remove a line discipline from the kernel providing it is not | |
725 | * currently in use. | |
726 | * | |
727 | * Locking: | |
728 | * takes tty_ldisc_lock to guard against ldisc races | |
729 | */ | |
730 | ||
bfb07599 AD |
731 | int tty_unregister_ldisc(int disc) |
732 | { | |
733 | unsigned long flags; | |
734 | int ret = 0; | |
735 | ||
736 | if (disc < N_TTY || disc >= NR_LDISCS) | |
737 | return -EINVAL; | |
738 | ||
739 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
740 | if (tty_ldiscs[disc].refcount) | |
741 | ret = -EBUSY; | |
742 | else | |
743 | tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; | |
744 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
745 | ||
746 | return ret; | |
747 | } | |
748 | EXPORT_SYMBOL(tty_unregister_ldisc); | |
749 | ||
af9b897e AC |
750 | /** |
751 | * tty_ldisc_get - take a reference to an ldisc | |
752 | * @disc: ldisc number | |
753 | * | |
754 | * Takes a reference to a line discipline. Deals with refcounts and | |
755 | * module locking counts. Returns NULL if the discipline is not available. | |
756 | * Returns a pointer to the discipline and bumps the ref count if it is | |
757 | * available | |
758 | * | |
759 | * Locking: | |
760 | * takes tty_ldisc_lock to guard against ldisc races | |
761 | */ | |
762 | ||
1da177e4 LT |
763 | struct tty_ldisc *tty_ldisc_get(int disc) |
764 | { | |
765 | unsigned long flags; | |
766 | struct tty_ldisc *ld; | |
767 | ||
768 | if (disc < N_TTY || disc >= NR_LDISCS) | |
769 | return NULL; | |
37bdfb07 | 770 | |
1da177e4 LT |
771 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
772 | ||
773 | ld = &tty_ldiscs[disc]; | |
774 | /* Check the entry is defined */ | |
37bdfb07 | 775 | if (ld->flags & LDISC_FLAG_DEFINED) { |
1da177e4 LT |
776 | /* If the module is being unloaded we can't use it */ |
777 | if (!try_module_get(ld->owner)) | |
37bdfb07 | 778 | ld = NULL; |
1da177e4 LT |
779 | else /* lock it */ |
780 | ld->refcount++; | |
37bdfb07 | 781 | } else |
1da177e4 LT |
782 | ld = NULL; |
783 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
784 | return ld; | |
785 | } | |
786 | ||
787 | EXPORT_SYMBOL_GPL(tty_ldisc_get); | |
788 | ||
af9b897e AC |
789 | /** |
790 | * tty_ldisc_put - drop ldisc reference | |
791 | * @disc: ldisc number | |
792 | * | |
793 | * Drop a reference to a line discipline. Manage refcounts and | |
794 | * module usage counts | |
795 | * | |
796 | * Locking: | |
797 | * takes tty_ldisc_lock to guard against ldisc races | |
798 | */ | |
799 | ||
1da177e4 LT |
800 | void tty_ldisc_put(int disc) |
801 | { | |
802 | struct tty_ldisc *ld; | |
803 | unsigned long flags; | |
37bdfb07 | 804 | |
56ee4827 | 805 | BUG_ON(disc < N_TTY || disc >= NR_LDISCS); |
37bdfb07 | 806 | |
1da177e4 LT |
807 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
808 | ld = &tty_ldiscs[disc]; | |
56ee4827 ES |
809 | BUG_ON(ld->refcount == 0); |
810 | ld->refcount--; | |
1da177e4 LT |
811 | module_put(ld->owner); |
812 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
813 | } | |
37bdfb07 | 814 | |
1da177e4 LT |
815 | EXPORT_SYMBOL_GPL(tty_ldisc_put); |
816 | ||
af9b897e AC |
817 | /** |
818 | * tty_ldisc_assign - set ldisc on a tty | |
819 | * @tty: tty to assign | |
820 | * @ld: line discipline | |
821 | * | |
822 | * Install an instance of a line discipline into a tty structure. The | |
823 | * ldisc must have a reference count above zero to ensure it remains/ | |
824 | * The tty instance refcount starts at zero. | |
825 | * | |
826 | * Locking: | |
827 | * Caller must hold references | |
828 | */ | |
829 | ||
1da177e4 LT |
830 | static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) |
831 | { | |
832 | tty->ldisc = *ld; | |
833 | tty->ldisc.refcount = 0; | |
834 | } | |
835 | ||
836 | /** | |
837 | * tty_ldisc_try - internal helper | |
838 | * @tty: the tty | |
839 | * | |
840 | * Make a single attempt to grab and bump the refcount on | |
841 | * the tty ldisc. Return 0 on failure or 1 on success. This is | |
842 | * used to implement both the waiting and non waiting versions | |
843 | * of tty_ldisc_ref | |
af9b897e AC |
844 | * |
845 | * Locking: takes tty_ldisc_lock | |
1da177e4 LT |
846 | */ |
847 | ||
848 | static int tty_ldisc_try(struct tty_struct *tty) | |
849 | { | |
850 | unsigned long flags; | |
851 | struct tty_ldisc *ld; | |
852 | int ret = 0; | |
37bdfb07 | 853 | |
1da177e4 LT |
854 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
855 | ld = &tty->ldisc; | |
37bdfb07 | 856 | if (test_bit(TTY_LDISC, &tty->flags)) { |
1da177e4 LT |
857 | ld->refcount++; |
858 | ret = 1; | |
859 | } | |
860 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
861 | return ret; | |
862 | } | |
863 | ||
864 | /** | |
865 | * tty_ldisc_ref_wait - wait for the tty ldisc | |
866 | * @tty: tty device | |
867 | * | |
37bdfb07 AC |
868 | * Dereference the line discipline for the terminal and take a |
869 | * reference to it. If the line discipline is in flux then | |
1da177e4 LT |
870 | * wait patiently until it changes. |
871 | * | |
872 | * Note: Must not be called from an IRQ/timer context. The caller | |
873 | * must also be careful not to hold other locks that will deadlock | |
874 | * against a discipline change, such as an existing ldisc reference | |
875 | * (which we check for) | |
af9b897e AC |
876 | * |
877 | * Locking: call functions take tty_ldisc_lock | |
1da177e4 | 878 | */ |
37bdfb07 | 879 | |
1da177e4 LT |
880 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) |
881 | { | |
882 | /* wait_event is a macro */ | |
883 | wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); | |
37bdfb07 | 884 | if (tty->ldisc.refcount == 0) |
1da177e4 LT |
885 | printk(KERN_ERR "tty_ldisc_ref_wait\n"); |
886 | return &tty->ldisc; | |
887 | } | |
888 | ||
889 | EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); | |
890 | ||
891 | /** | |
892 | * tty_ldisc_ref - get the tty ldisc | |
893 | * @tty: tty device | |
894 | * | |
37bdfb07 AC |
895 | * Dereference the line discipline for the terminal and take a |
896 | * reference to it. If the line discipline is in flux then | |
1da177e4 | 897 | * return NULL. Can be called from IRQ and timer functions. |
af9b897e AC |
898 | * |
899 | * Locking: called functions take tty_ldisc_lock | |
1da177e4 | 900 | */ |
37bdfb07 | 901 | |
1da177e4 LT |
902 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) |
903 | { | |
37bdfb07 | 904 | if (tty_ldisc_try(tty)) |
1da177e4 LT |
905 | return &tty->ldisc; |
906 | return NULL; | |
907 | } | |
908 | ||
909 | EXPORT_SYMBOL_GPL(tty_ldisc_ref); | |
910 | ||
911 | /** | |
912 | * tty_ldisc_deref - free a tty ldisc reference | |
913 | * @ld: reference to free up | |
914 | * | |
915 | * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May | |
916 | * be called in IRQ context. | |
af9b897e AC |
917 | * |
918 | * Locking: takes tty_ldisc_lock | |
1da177e4 | 919 | */ |
37bdfb07 | 920 | |
1da177e4 LT |
921 | void tty_ldisc_deref(struct tty_ldisc *ld) |
922 | { | |
923 | unsigned long flags; | |
924 | ||
56ee4827 | 925 | BUG_ON(ld == NULL); |
37bdfb07 | 926 | |
1da177e4 | 927 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
37bdfb07 | 928 | if (ld->refcount == 0) |
1da177e4 LT |
929 | printk(KERN_ERR "tty_ldisc_deref: no references.\n"); |
930 | else | |
931 | ld->refcount--; | |
37bdfb07 | 932 | if (ld->refcount == 0) |
1da177e4 LT |
933 | wake_up(&tty_ldisc_wait); |
934 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
935 | } | |
936 | ||
937 | EXPORT_SYMBOL_GPL(tty_ldisc_deref); | |
938 | ||
939 | /** | |
940 | * tty_ldisc_enable - allow ldisc use | |
941 | * @tty: terminal to activate ldisc on | |
942 | * | |
943 | * Set the TTY_LDISC flag when the line discipline can be called | |
3a4fa0a2 | 944 | * again. Do necessary wakeups for existing sleepers. |
1da177e4 LT |
945 | * |
946 | * Note: nobody should set this bit except via this function. Clearing | |
947 | * directly is allowed. | |
948 | */ | |
949 | ||
950 | static void tty_ldisc_enable(struct tty_struct *tty) | |
951 | { | |
952 | set_bit(TTY_LDISC, &tty->flags); | |
953 | wake_up(&tty_ldisc_wait); | |
954 | } | |
37bdfb07 | 955 | |
1da177e4 LT |
956 | /** |
957 | * tty_set_ldisc - set line discipline | |
958 | * @tty: the terminal to set | |
959 | * @ldisc: the line discipline | |
960 | * | |
961 | * Set the discipline of a tty line. Must be called from a process | |
962 | * context. | |
af9b897e AC |
963 | * |
964 | * Locking: takes tty_ldisc_lock. | |
24ec839c | 965 | * called functions take termios_mutex |
1da177e4 | 966 | */ |
37bdfb07 | 967 | |
1da177e4 LT |
968 | static int tty_set_ldisc(struct tty_struct *tty, int ldisc) |
969 | { | |
ff55fe20 JB |
970 | int retval = 0; |
971 | struct tty_ldisc o_ldisc; | |
1da177e4 LT |
972 | char buf[64]; |
973 | int work; | |
974 | unsigned long flags; | |
975 | struct tty_ldisc *ld; | |
ff55fe20 | 976 | struct tty_struct *o_tty; |
1da177e4 LT |
977 | |
978 | if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) | |
979 | return -EINVAL; | |
980 | ||
981 | restart: | |
982 | ||
1da177e4 LT |
983 | ld = tty_ldisc_get(ldisc); |
984 | /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ | |
985 | /* Cyrus Durgin <cider@speakeasy.org> */ | |
986 | if (ld == NULL) { | |
987 | request_module("tty-ldisc-%d", ldisc); | |
988 | ld = tty_ldisc_get(ldisc); | |
989 | } | |
990 | if (ld == NULL) | |
991 | return -EINVAL; | |
992 | ||
33f0f88f AC |
993 | /* |
994 | * Problem: What do we do if this blocks ? | |
995 | */ | |
996 | ||
1da177e4 LT |
997 | tty_wait_until_sent(tty, 0); |
998 | ||
ff55fe20 JB |
999 | if (tty->ldisc.num == ldisc) { |
1000 | tty_ldisc_put(ldisc); | |
1001 | return 0; | |
1002 | } | |
1003 | ||
ae030e43 PF |
1004 | /* |
1005 | * No more input please, we are switching. The new ldisc | |
1006 | * will update this value in the ldisc open function | |
1007 | */ | |
1008 | ||
1009 | tty->receive_room = 0; | |
1010 | ||
ff55fe20 JB |
1011 | o_ldisc = tty->ldisc; |
1012 | o_tty = tty->link; | |
1013 | ||
1da177e4 LT |
1014 | /* |
1015 | * Make sure we don't change while someone holds a | |
1016 | * reference to the line discipline. The TTY_LDISC bit | |
1017 | * prevents anyone taking a reference once it is clear. | |
1018 | * We need the lock to avoid racing reference takers. | |
1019 | */ | |
ff55fe20 | 1020 | |
1da177e4 | 1021 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
ff55fe20 | 1022 | if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { |
37bdfb07 | 1023 | if (tty->ldisc.refcount) { |
ff55fe20 JB |
1024 | /* Free the new ldisc we grabbed. Must drop the lock |
1025 | first. */ | |
1026 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
1027 | tty_ldisc_put(ldisc); | |
1028 | /* | |
1029 | * There are several reasons we may be busy, including | |
1030 | * random momentary I/O traffic. We must therefore | |
1031 | * retry. We could distinguish between blocking ops | |
37bdfb07 AC |
1032 | * and retries if we made tty_ldisc_wait() smarter. |
1033 | * That is up for discussion. | |
ff55fe20 JB |
1034 | */ |
1035 | if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) | |
1036 | return -ERESTARTSYS; | |
1037 | goto restart; | |
1038 | } | |
37bdfb07 | 1039 | if (o_tty && o_tty->ldisc.refcount) { |
ff55fe20 JB |
1040 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
1041 | tty_ldisc_put(ldisc); | |
1042 | if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) | |
1043 | return -ERESTARTSYS; | |
1044 | goto restart; | |
1045 | } | |
1046 | } | |
37bdfb07 AC |
1047 | /* |
1048 | * If the TTY_LDISC bit is set, then we are racing against | |
1049 | * another ldisc change | |
1050 | */ | |
ff55fe20 | 1051 | if (!test_bit(TTY_LDISC, &tty->flags)) { |
1da177e4 LT |
1052 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
1053 | tty_ldisc_put(ldisc); | |
ff55fe20 JB |
1054 | ld = tty_ldisc_ref_wait(tty); |
1055 | tty_ldisc_deref(ld); | |
1da177e4 LT |
1056 | goto restart; |
1057 | } | |
ff55fe20 JB |
1058 | |
1059 | clear_bit(TTY_LDISC, &tty->flags); | |
817d6d3b | 1060 | if (o_tty) |
ff55fe20 | 1061 | clear_bit(TTY_LDISC, &o_tty->flags); |
1da177e4 | 1062 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
ff55fe20 | 1063 | |
1da177e4 LT |
1064 | /* |
1065 | * From this point on we know nobody has an ldisc | |
1066 | * usage reference, nor can they obtain one until | |
1067 | * we say so later on. | |
1068 | */ | |
ff55fe20 | 1069 | |
33f0f88f | 1070 | work = cancel_delayed_work(&tty->buf.work); |
1da177e4 | 1071 | /* |
33f0f88f | 1072 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 | 1073 | */ |
1da177e4 LT |
1074 | flush_scheduled_work(); |
1075 | /* Shutdown the current discipline. */ | |
1076 | if (tty->ldisc.close) | |
1077 | (tty->ldisc.close)(tty); | |
1078 | ||
1079 | /* Now set up the new line discipline. */ | |
1080 | tty_ldisc_assign(tty, ld); | |
1081 | tty_set_termios_ldisc(tty, ldisc); | |
1082 | if (tty->ldisc.open) | |
1083 | retval = (tty->ldisc.open)(tty); | |
1084 | if (retval < 0) { | |
1085 | tty_ldisc_put(ldisc); | |
1086 | /* There is an outstanding reference here so this is safe */ | |
1087 | tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); | |
1088 | tty_set_termios_ldisc(tty, tty->ldisc.num); | |
1089 | if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { | |
1090 | tty_ldisc_put(o_ldisc.num); | |
1091 | /* This driver is always present */ | |
1092 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
1093 | tty_set_termios_ldisc(tty, N_TTY); | |
1094 | if (tty->ldisc.open) { | |
1095 | int r = tty->ldisc.open(tty); | |
1096 | ||
1097 | if (r < 0) | |
1098 | panic("Couldn't open N_TTY ldisc for " | |
1099 | "%s --- error %d.", | |
1100 | tty_name(tty, buf), r); | |
1101 | } | |
1102 | } | |
1103 | } | |
1104 | /* At this point we hold a reference to the new ldisc and a | |
1105 | a reference to the old ldisc. If we ended up flipping back | |
1106 | to the existing ldisc we have two references to it */ | |
37bdfb07 | 1107 | |
f34d7a5b AC |
1108 | if (tty->ldisc.num != o_ldisc.num && tty->ops->set_ldisc) |
1109 | tty->ops->set_ldisc(tty); | |
37bdfb07 | 1110 | |
1da177e4 | 1111 | tty_ldisc_put(o_ldisc.num); |
37bdfb07 | 1112 | |
1da177e4 LT |
1113 | /* |
1114 | * Allow ldisc referencing to occur as soon as the driver | |
1115 | * ldisc callback completes. | |
1116 | */ | |
37bdfb07 | 1117 | |
1da177e4 | 1118 | tty_ldisc_enable(tty); |
ff55fe20 JB |
1119 | if (o_tty) |
1120 | tty_ldisc_enable(o_tty); | |
37bdfb07 | 1121 | |
1da177e4 LT |
1122 | /* Restart it in case no characters kick it off. Safe if |
1123 | already running */ | |
ff55fe20 | 1124 | if (work) |
33f0f88f | 1125 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
1126 | return retval; |
1127 | } | |
1128 | ||
af9b897e AC |
1129 | /** |
1130 | * get_tty_driver - find device of a tty | |
1131 | * @dev_t: device identifier | |
1132 | * @index: returns the index of the tty | |
1133 | * | |
1134 | * This routine returns a tty driver structure, given a device number | |
1135 | * and also passes back the index number. | |
1136 | * | |
1137 | * Locking: caller must hold tty_mutex | |
1da177e4 | 1138 | */ |
af9b897e | 1139 | |
1da177e4 LT |
1140 | static struct tty_driver *get_tty_driver(dev_t device, int *index) |
1141 | { | |
1142 | struct tty_driver *p; | |
1143 | ||
1144 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1145 | dev_t base = MKDEV(p->major, p->minor_start); | |
1146 | if (device < base || device >= base + p->num) | |
1147 | continue; | |
1148 | *index = device - base; | |
1149 | return p; | |
1150 | } | |
1151 | return NULL; | |
1152 | } | |
1153 | ||
f2d937f3 JW |
1154 | #ifdef CONFIG_CONSOLE_POLL |
1155 | ||
1156 | /** | |
1157 | * tty_find_polling_driver - find device of a polled tty | |
1158 | * @name: name string to match | |
1159 | * @line: pointer to resulting tty line nr | |
1160 | * | |
1161 | * This routine returns a tty driver structure, given a name | |
1162 | * and the condition that the tty driver is capable of polled | |
1163 | * operation. | |
1164 | */ | |
1165 | struct tty_driver *tty_find_polling_driver(char *name, int *line) | |
1166 | { | |
1167 | struct tty_driver *p, *res = NULL; | |
1168 | int tty_line = 0; | |
1169 | char *str; | |
1170 | ||
1171 | mutex_lock(&tty_mutex); | |
1172 | /* Search through the tty devices to look for a match */ | |
1173 | list_for_each_entry(p, &tty_drivers, tty_drivers) { | |
1174 | str = name + strlen(p->name); | |
1175 | tty_line = simple_strtoul(str, &str, 10); | |
1176 | if (*str == ',') | |
1177 | str++; | |
1178 | if (*str == '\0') | |
8da56309 | 1179 | str = NULL; |
f2d937f3 | 1180 | |
f34d7a5b AC |
1181 | if (tty_line >= 0 && tty_line <= p->num && p->ops && |
1182 | p->ops->poll_init && !p->ops->poll_init(p, tty_line, str)) { | |
f2d937f3 JW |
1183 | res = p; |
1184 | *line = tty_line; | |
1185 | break; | |
1186 | } | |
1187 | } | |
1188 | mutex_unlock(&tty_mutex); | |
1189 | ||
1190 | return res; | |
1191 | } | |
1192 | EXPORT_SYMBOL_GPL(tty_find_polling_driver); | |
1193 | #endif | |
1194 | ||
af9b897e AC |
1195 | /** |
1196 | * tty_check_change - check for POSIX terminal changes | |
1197 | * @tty: tty to check | |
1198 | * | |
1199 | * If we try to write to, or set the state of, a terminal and we're | |
1200 | * not in the foreground, send a SIGTTOU. If the signal is blocked or | |
1201 | * ignored, go ahead and perform the operation. (POSIX 7.2) | |
1202 | * | |
978e595f | 1203 | * Locking: ctrl_lock |
1da177e4 | 1204 | */ |
af9b897e | 1205 | |
37bdfb07 | 1206 | int tty_check_change(struct tty_struct *tty) |
1da177e4 | 1207 | { |
47f86834 AC |
1208 | unsigned long flags; |
1209 | int ret = 0; | |
1210 | ||
1da177e4 LT |
1211 | if (current->signal->tty != tty) |
1212 | return 0; | |
47f86834 AC |
1213 | |
1214 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
1215 | ||
ab521dc0 EB |
1216 | if (!tty->pgrp) { |
1217 | printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n"); | |
9ffee4cb | 1218 | goto out_unlock; |
1da177e4 | 1219 | } |
ab521dc0 | 1220 | if (task_pgrp(current) == tty->pgrp) |
9ffee4cb AM |
1221 | goto out_unlock; |
1222 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
1da177e4 | 1223 | if (is_ignored(SIGTTOU)) |
47f86834 AC |
1224 | goto out; |
1225 | if (is_current_pgrp_orphaned()) { | |
1226 | ret = -EIO; | |
1227 | goto out; | |
1228 | } | |
040b6362 ON |
1229 | kill_pgrp(task_pgrp(current), SIGTTOU, 1); |
1230 | set_thread_flag(TIF_SIGPENDING); | |
47f86834 AC |
1231 | ret = -ERESTARTSYS; |
1232 | out: | |
9ffee4cb AM |
1233 | return ret; |
1234 | out_unlock: | |
47f86834 AC |
1235 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1236 | return ret; | |
1da177e4 LT |
1237 | } |
1238 | ||
1239 | EXPORT_SYMBOL(tty_check_change); | |
1240 | ||
37bdfb07 | 1241 | static ssize_t hung_up_tty_read(struct file *file, char __user *buf, |
1da177e4 LT |
1242 | size_t count, loff_t *ppos) |
1243 | { | |
1244 | return 0; | |
1245 | } | |
1246 | ||
37bdfb07 | 1247 | static ssize_t hung_up_tty_write(struct file *file, const char __user *buf, |
1da177e4 LT |
1248 | size_t count, loff_t *ppos) |
1249 | { | |
1250 | return -EIO; | |
1251 | } | |
1252 | ||
1253 | /* No kernel lock held - none needed ;) */ | |
37bdfb07 | 1254 | static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait) |
1da177e4 LT |
1255 | { |
1256 | return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; | |
1257 | } | |
1258 | ||
04f378b1 AC |
1259 | static long hung_up_tty_ioctl(struct file *file, unsigned int cmd, |
1260 | unsigned long arg) | |
38ad2ed0 PF |
1261 | { |
1262 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1263 | } | |
1264 | ||
37bdfb07 | 1265 | static long hung_up_tty_compat_ioctl(struct file *file, |
38ad2ed0 | 1266 | unsigned int cmd, unsigned long arg) |
1da177e4 LT |
1267 | { |
1268 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; | |
1269 | } | |
1270 | ||
62322d25 | 1271 | static const struct file_operations tty_fops = { |
1da177e4 LT |
1272 | .llseek = no_llseek, |
1273 | .read = tty_read, | |
1274 | .write = tty_write, | |
1275 | .poll = tty_poll, | |
04f378b1 | 1276 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1277 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1278 | .open = tty_open, |
1279 | .release = tty_release, | |
1280 | .fasync = tty_fasync, | |
1281 | }; | |
1282 | ||
1283 | #ifdef CONFIG_UNIX98_PTYS | |
62322d25 | 1284 | static const struct file_operations ptmx_fops = { |
1da177e4 LT |
1285 | .llseek = no_llseek, |
1286 | .read = tty_read, | |
1287 | .write = tty_write, | |
1288 | .poll = tty_poll, | |
04f378b1 | 1289 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1290 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1291 | .open = ptmx_open, |
1292 | .release = tty_release, | |
1293 | .fasync = tty_fasync, | |
1294 | }; | |
1295 | #endif | |
1296 | ||
62322d25 | 1297 | static const struct file_operations console_fops = { |
1da177e4 LT |
1298 | .llseek = no_llseek, |
1299 | .read = tty_read, | |
1300 | .write = redirected_tty_write, | |
1301 | .poll = tty_poll, | |
04f378b1 | 1302 | .unlocked_ioctl = tty_ioctl, |
e10cc1df | 1303 | .compat_ioctl = tty_compat_ioctl, |
1da177e4 LT |
1304 | .open = tty_open, |
1305 | .release = tty_release, | |
1306 | .fasync = tty_fasync, | |
1307 | }; | |
1308 | ||
62322d25 | 1309 | static const struct file_operations hung_up_tty_fops = { |
1da177e4 LT |
1310 | .llseek = no_llseek, |
1311 | .read = hung_up_tty_read, | |
1312 | .write = hung_up_tty_write, | |
1313 | .poll = hung_up_tty_poll, | |
04f378b1 | 1314 | .unlocked_ioctl = hung_up_tty_ioctl, |
38ad2ed0 | 1315 | .compat_ioctl = hung_up_tty_compat_ioctl, |
1da177e4 LT |
1316 | .release = tty_release, |
1317 | }; | |
1318 | ||
1319 | static DEFINE_SPINLOCK(redirect_lock); | |
1320 | static struct file *redirect; | |
1321 | ||
1322 | /** | |
1323 | * tty_wakeup - request more data | |
1324 | * @tty: terminal | |
1325 | * | |
1326 | * Internal and external helper for wakeups of tty. This function | |
1327 | * informs the line discipline if present that the driver is ready | |
1328 | * to receive more output data. | |
1329 | */ | |
37bdfb07 | 1330 | |
1da177e4 LT |
1331 | void tty_wakeup(struct tty_struct *tty) |
1332 | { | |
1333 | struct tty_ldisc *ld; | |
37bdfb07 | 1334 | |
1da177e4 LT |
1335 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { |
1336 | ld = tty_ldisc_ref(tty); | |
37bdfb07 AC |
1337 | if (ld) { |
1338 | if (ld->write_wakeup) | |
1da177e4 LT |
1339 | ld->write_wakeup(tty); |
1340 | tty_ldisc_deref(ld); | |
1341 | } | |
1342 | } | |
1343 | wake_up_interruptible(&tty->write_wait); | |
1344 | } | |
1345 | ||
1346 | EXPORT_SYMBOL_GPL(tty_wakeup); | |
1347 | ||
1348 | /** | |
1349 | * tty_ldisc_flush - flush line discipline queue | |
1350 | * @tty: tty | |
1351 | * | |
1352 | * Flush the line discipline queue (if any) for this tty. If there | |
1353 | * is no line discipline active this is a no-op. | |
1354 | */ | |
37bdfb07 | 1355 | |
1da177e4 LT |
1356 | void tty_ldisc_flush(struct tty_struct *tty) |
1357 | { | |
1358 | struct tty_ldisc *ld = tty_ldisc_ref(tty); | |
37bdfb07 AC |
1359 | if (ld) { |
1360 | if (ld->flush_buffer) | |
1da177e4 LT |
1361 | ld->flush_buffer(tty); |
1362 | tty_ldisc_deref(ld); | |
1363 | } | |
c5c34d48 | 1364 | tty_buffer_flush(tty); |
1da177e4 LT |
1365 | } |
1366 | ||
1367 | EXPORT_SYMBOL_GPL(tty_ldisc_flush); | |
edc6afc5 AC |
1368 | |
1369 | /** | |
1370 | * tty_reset_termios - reset terminal state | |
1371 | * @tty: tty to reset | |
1372 | * | |
1373 | * Restore a terminal to the driver default state | |
1374 | */ | |
1375 | ||
1376 | static void tty_reset_termios(struct tty_struct *tty) | |
1377 | { | |
1378 | mutex_lock(&tty->termios_mutex); | |
1379 | *tty->termios = tty->driver->init_termios; | |
1380 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
1381 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1382 | mutex_unlock(&tty->termios_mutex); | |
1383 | } | |
37bdfb07 | 1384 | |
af9b897e AC |
1385 | /** |
1386 | * do_tty_hangup - actual handler for hangup events | |
65f27f38 | 1387 | * @work: tty device |
af9b897e AC |
1388 | * |
1389 | * This can be called by the "eventd" kernel thread. That is process | |
1390 | * synchronous but doesn't hold any locks, so we need to make sure we | |
1391 | * have the appropriate locks for what we're doing. | |
1392 | * | |
1393 | * The hangup event clears any pending redirections onto the hung up | |
1394 | * device. It ensures future writes will error and it does the needed | |
1395 | * line discipline hangup and signal delivery. The tty object itself | |
1396 | * remains intact. | |
1397 | * | |
1398 | * Locking: | |
1399 | * BKL | |
24ec839c PZ |
1400 | * redirect lock for undoing redirection |
1401 | * file list lock for manipulating list of ttys | |
1402 | * tty_ldisc_lock from called functions | |
1403 | * termios_mutex resetting termios data | |
1404 | * tasklist_lock to walk task list for hangup event | |
1405 | * ->siglock to protect ->signal/->sighand | |
1da177e4 | 1406 | */ |
65f27f38 | 1407 | static void do_tty_hangup(struct work_struct *work) |
1da177e4 | 1408 | { |
65f27f38 DH |
1409 | struct tty_struct *tty = |
1410 | container_of(work, struct tty_struct, hangup_work); | |
37bdfb07 | 1411 | struct file *cons_filp = NULL; |
1da177e4 LT |
1412 | struct file *filp, *f = NULL; |
1413 | struct task_struct *p; | |
1414 | struct tty_ldisc *ld; | |
1415 | int closecount = 0, n; | |
47f86834 | 1416 | unsigned long flags; |
1da177e4 LT |
1417 | |
1418 | if (!tty) | |
1419 | return; | |
1420 | ||
1421 | /* inuse_filps is protected by the single kernel lock */ | |
1422 | lock_kernel(); | |
1423 | ||
1424 | spin_lock(&redirect_lock); | |
1425 | if (redirect && redirect->private_data == tty) { | |
1426 | f = redirect; | |
1427 | redirect = NULL; | |
1428 | } | |
1429 | spin_unlock(&redirect_lock); | |
37bdfb07 | 1430 | |
1da177e4 LT |
1431 | check_tty_count(tty, "do_tty_hangup"); |
1432 | file_list_lock(); | |
1433 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ | |
2f512016 | 1434 | list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { |
1da177e4 LT |
1435 | if (filp->f_op->write == redirected_tty_write) |
1436 | cons_filp = filp; | |
1437 | if (filp->f_op->write != tty_write) | |
1438 | continue; | |
1439 | closecount++; | |
1440 | tty_fasync(-1, filp, 0); /* can't block */ | |
1441 | filp->f_op = &hung_up_tty_fops; | |
1442 | } | |
1443 | file_list_unlock(); | |
37bdfb07 AC |
1444 | /* |
1445 | * FIXME! What are the locking issues here? This may me overdoing | |
1446 | * things... This question is especially important now that we've | |
1447 | * removed the irqlock. | |
1448 | */ | |
1da177e4 | 1449 | ld = tty_ldisc_ref(tty); |
37bdfb07 AC |
1450 | if (ld != NULL) { |
1451 | /* We may have no line discipline at this point */ | |
1da177e4 LT |
1452 | if (ld->flush_buffer) |
1453 | ld->flush_buffer(tty); | |
f34d7a5b | 1454 | tty_driver_flush_buffer(tty); |
1da177e4 LT |
1455 | if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && |
1456 | ld->write_wakeup) | |
1457 | ld->write_wakeup(tty); | |
1458 | if (ld->hangup) | |
1459 | ld->hangup(tty); | |
1460 | } | |
37bdfb07 AC |
1461 | /* |
1462 | * FIXME: Once we trust the LDISC code better we can wait here for | |
1463 | * ldisc completion and fix the driver call race | |
1464 | */ | |
1da177e4 LT |
1465 | wake_up_interruptible(&tty->write_wait); |
1466 | wake_up_interruptible(&tty->read_wait); | |
1da177e4 LT |
1467 | /* |
1468 | * Shutdown the current line discipline, and reset it to | |
1469 | * N_TTY. | |
1470 | */ | |
1471 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) | |
edc6afc5 | 1472 | tty_reset_termios(tty); |
1da177e4 LT |
1473 | /* Defer ldisc switch */ |
1474 | /* tty_deferred_ldisc_switch(N_TTY); | |
37bdfb07 | 1475 | |
1da177e4 LT |
1476 | This should get done automatically when the port closes and |
1477 | tty_release is called */ | |
37bdfb07 | 1478 | |
1da177e4 | 1479 | read_lock(&tasklist_lock); |
ab521dc0 EB |
1480 | if (tty->session) { |
1481 | do_each_pid_task(tty->session, PIDTYPE_SID, p) { | |
24ec839c | 1482 | spin_lock_irq(&p->sighand->siglock); |
1da177e4 LT |
1483 | if (p->signal->tty == tty) |
1484 | p->signal->tty = NULL; | |
24ec839c PZ |
1485 | if (!p->signal->leader) { |
1486 | spin_unlock_irq(&p->sighand->siglock); | |
1da177e4 | 1487 | continue; |
24ec839c PZ |
1488 | } |
1489 | __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); | |
1490 | __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); | |
ab521dc0 | 1491 | put_pid(p->signal->tty_old_pgrp); /* A noop */ |
47f86834 | 1492 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
ab521dc0 EB |
1493 | if (tty->pgrp) |
1494 | p->signal->tty_old_pgrp = get_pid(tty->pgrp); | |
47f86834 | 1495 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
24ec839c | 1496 | spin_unlock_irq(&p->sighand->siglock); |
ab521dc0 | 1497 | } while_each_pid_task(tty->session, PIDTYPE_SID, p); |
1da177e4 LT |
1498 | } |
1499 | read_unlock(&tasklist_lock); | |
1500 | ||
47f86834 | 1501 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
1da177e4 | 1502 | tty->flags = 0; |
d9c1e9a8 EB |
1503 | put_pid(tty->session); |
1504 | put_pid(tty->pgrp); | |
ab521dc0 EB |
1505 | tty->session = NULL; |
1506 | tty->pgrp = NULL; | |
1da177e4 | 1507 | tty->ctrl_status = 0; |
47f86834 AC |
1508 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
1509 | ||
1da177e4 | 1510 | /* |
37bdfb07 AC |
1511 | * If one of the devices matches a console pointer, we |
1512 | * cannot just call hangup() because that will cause | |
1513 | * tty->count and state->count to go out of sync. | |
1514 | * So we just call close() the right number of times. | |
1da177e4 LT |
1515 | */ |
1516 | if (cons_filp) { | |
f34d7a5b | 1517 | if (tty->ops->close) |
1da177e4 | 1518 | for (n = 0; n < closecount; n++) |
f34d7a5b AC |
1519 | tty->ops->close(tty, cons_filp); |
1520 | } else if (tty->ops->hangup) | |
1521 | (tty->ops->hangup)(tty); | |
37bdfb07 AC |
1522 | /* |
1523 | * We don't want to have driver/ldisc interactions beyond | |
1524 | * the ones we did here. The driver layer expects no | |
1525 | * calls after ->hangup() from the ldisc side. However we | |
1526 | * can't yet guarantee all that. | |
1527 | */ | |
1da177e4 LT |
1528 | set_bit(TTY_HUPPED, &tty->flags); |
1529 | if (ld) { | |
1530 | tty_ldisc_enable(tty); | |
1531 | tty_ldisc_deref(ld); | |
1532 | } | |
1533 | unlock_kernel(); | |
1534 | if (f) | |
1535 | fput(f); | |
1536 | } | |
1537 | ||
af9b897e AC |
1538 | /** |
1539 | * tty_hangup - trigger a hangup event | |
1540 | * @tty: tty to hangup | |
1541 | * | |
1542 | * A carrier loss (virtual or otherwise) has occurred on this like | |
1543 | * schedule a hangup sequence to run after this event. | |
1544 | */ | |
1545 | ||
37bdfb07 | 1546 | void tty_hangup(struct tty_struct *tty) |
1da177e4 LT |
1547 | { |
1548 | #ifdef TTY_DEBUG_HANGUP | |
1549 | char buf[64]; | |
1da177e4 LT |
1550 | printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); |
1551 | #endif | |
1552 | schedule_work(&tty->hangup_work); | |
1553 | } | |
1554 | ||
1555 | EXPORT_SYMBOL(tty_hangup); | |
1556 | ||
af9b897e AC |
1557 | /** |
1558 | * tty_vhangup - process vhangup | |
1559 | * @tty: tty to hangup | |
1560 | * | |
1561 | * The user has asked via system call for the terminal to be hung up. | |
1562 | * We do this synchronously so that when the syscall returns the process | |
3a4fa0a2 | 1563 | * is complete. That guarantee is necessary for security reasons. |
af9b897e AC |
1564 | */ |
1565 | ||
37bdfb07 | 1566 | void tty_vhangup(struct tty_struct *tty) |
1da177e4 LT |
1567 | { |
1568 | #ifdef TTY_DEBUG_HANGUP | |
1569 | char buf[64]; | |
1570 | ||
1571 | printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); | |
1572 | #endif | |
65f27f38 | 1573 | do_tty_hangup(&tty->hangup_work); |
1da177e4 | 1574 | } |
37bdfb07 | 1575 | |
1da177e4 LT |
1576 | EXPORT_SYMBOL(tty_vhangup); |
1577 | ||
af9b897e AC |
1578 | /** |
1579 | * tty_hung_up_p - was tty hung up | |
1580 | * @filp: file pointer of tty | |
1581 | * | |
1582 | * Return true if the tty has been subject to a vhangup or a carrier | |
1583 | * loss | |
1584 | */ | |
1585 | ||
37bdfb07 | 1586 | int tty_hung_up_p(struct file *filp) |
1da177e4 LT |
1587 | { |
1588 | return (filp->f_op == &hung_up_tty_fops); | |
1589 | } | |
1590 | ||
1591 | EXPORT_SYMBOL(tty_hung_up_p); | |
1592 | ||
522ed776 | 1593 | /** |
37bdfb07 AC |
1594 | * is_tty - checker whether file is a TTY |
1595 | * @filp: file handle that may be a tty | |
1596 | * | |
1597 | * Check if the file handle is a tty handle. | |
522ed776 | 1598 | */ |
37bdfb07 | 1599 | |
522ed776 MT |
1600 | int is_tty(struct file *filp) |
1601 | { | |
1602 | return filp->f_op->read == tty_read | |
1603 | || filp->f_op->read == hung_up_tty_read; | |
1604 | } | |
1605 | ||
ab521dc0 | 1606 | static void session_clear_tty(struct pid *session) |
24ec839c PZ |
1607 | { |
1608 | struct task_struct *p; | |
ab521dc0 | 1609 | do_each_pid_task(session, PIDTYPE_SID, p) { |
24ec839c | 1610 | proc_clear_tty(p); |
ab521dc0 | 1611 | } while_each_pid_task(session, PIDTYPE_SID, p); |
24ec839c PZ |
1612 | } |
1613 | ||
af9b897e AC |
1614 | /** |
1615 | * disassociate_ctty - disconnect controlling tty | |
1616 | * @on_exit: true if exiting so need to "hang up" the session | |
1da177e4 | 1617 | * |
af9b897e AC |
1618 | * This function is typically called only by the session leader, when |
1619 | * it wants to disassociate itself from its controlling tty. | |
1620 | * | |
1621 | * It performs the following functions: | |
1da177e4 LT |
1622 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
1623 | * (2) Clears the tty from being controlling the session | |
1624 | * (3) Clears the controlling tty for all processes in the | |
1625 | * session group. | |
1626 | * | |
af9b897e AC |
1627 | * The argument on_exit is set to 1 if called when a process is |
1628 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. | |
1629 | * | |
24ec839c | 1630 | * Locking: |
af9b897e | 1631 | * BKL is taken for hysterical raisins |
24ec839c PZ |
1632 | * tty_mutex is taken to protect tty |
1633 | * ->siglock is taken to protect ->signal/->sighand | |
1634 | * tasklist_lock is taken to walk process list for sessions | |
1635 | * ->siglock is taken to protect ->signal/->sighand | |
1da177e4 | 1636 | */ |
af9b897e | 1637 | |
1da177e4 LT |
1638 | void disassociate_ctty(int on_exit) |
1639 | { | |
1640 | struct tty_struct *tty; | |
ab521dc0 | 1641 | struct pid *tty_pgrp = NULL; |
1da177e4 | 1642 | |
1da177e4 | 1643 | |
70522e12 | 1644 | mutex_lock(&tty_mutex); |
24ec839c | 1645 | tty = get_current_tty(); |
1da177e4 | 1646 | if (tty) { |
ab521dc0 | 1647 | tty_pgrp = get_pid(tty->pgrp); |
70522e12 | 1648 | mutex_unlock(&tty_mutex); |
04f378b1 | 1649 | lock_kernel(); |
24ec839c | 1650 | /* XXX: here we race, there is nothing protecting tty */ |
1da177e4 LT |
1651 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
1652 | tty_vhangup(tty); | |
04f378b1 | 1653 | unlock_kernel(); |
680a9671 | 1654 | } else if (on_exit) { |
ab521dc0 | 1655 | struct pid *old_pgrp; |
680a9671 EB |
1656 | spin_lock_irq(¤t->sighand->siglock); |
1657 | old_pgrp = current->signal->tty_old_pgrp; | |
ab521dc0 | 1658 | current->signal->tty_old_pgrp = NULL; |
680a9671 | 1659 | spin_unlock_irq(¤t->sighand->siglock); |
24ec839c | 1660 | if (old_pgrp) { |
ab521dc0 EB |
1661 | kill_pgrp(old_pgrp, SIGHUP, on_exit); |
1662 | kill_pgrp(old_pgrp, SIGCONT, on_exit); | |
1663 | put_pid(old_pgrp); | |
1da177e4 | 1664 | } |
70522e12 | 1665 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
1666 | return; |
1667 | } | |
ab521dc0 EB |
1668 | if (tty_pgrp) { |
1669 | kill_pgrp(tty_pgrp, SIGHUP, on_exit); | |
1da177e4 | 1670 | if (!on_exit) |
ab521dc0 EB |
1671 | kill_pgrp(tty_pgrp, SIGCONT, on_exit); |
1672 | put_pid(tty_pgrp); | |
1da177e4 LT |
1673 | } |
1674 | ||
24ec839c | 1675 | spin_lock_irq(¤t->sighand->siglock); |
2a65f1d9 | 1676 | put_pid(current->signal->tty_old_pgrp); |
23cac8de | 1677 | current->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
1678 | spin_unlock_irq(¤t->sighand->siglock); |
1679 | ||
1680 | mutex_lock(&tty_mutex); | |
1681 | /* It is possible that do_tty_hangup has free'd this tty */ | |
1682 | tty = get_current_tty(); | |
1683 | if (tty) { | |
47f86834 AC |
1684 | unsigned long flags; |
1685 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
ab521dc0 EB |
1686 | put_pid(tty->session); |
1687 | put_pid(tty->pgrp); | |
1688 | tty->session = NULL; | |
1689 | tty->pgrp = NULL; | |
47f86834 | 1690 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
24ec839c PZ |
1691 | } else { |
1692 | #ifdef TTY_DEBUG_HANGUP | |
1693 | printk(KERN_DEBUG "error attempted to write to tty [0x%p]" | |
1694 | " = NULL", tty); | |
1695 | #endif | |
1696 | } | |
1697 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
1698 | |
1699 | /* Now clear signal->tty under the lock */ | |
1700 | read_lock(&tasklist_lock); | |
ab521dc0 | 1701 | session_clear_tty(task_session(current)); |
1da177e4 | 1702 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1703 | } |
1704 | ||
98a27ba4 EB |
1705 | /** |
1706 | * | |
1707 | * no_tty - Ensure the current process does not have a controlling tty | |
1708 | */ | |
1709 | void no_tty(void) | |
1710 | { | |
1711 | struct task_struct *tsk = current; | |
04f378b1 | 1712 | lock_kernel(); |
98a27ba4 EB |
1713 | if (tsk->signal->leader) |
1714 | disassociate_ctty(0); | |
04f378b1 | 1715 | unlock_kernel(); |
98a27ba4 EB |
1716 | proc_clear_tty(tsk); |
1717 | } | |
1718 | ||
af9b897e AC |
1719 | |
1720 | /** | |
beb7dd86 | 1721 | * stop_tty - propagate flow control |
af9b897e AC |
1722 | * @tty: tty to stop |
1723 | * | |
1724 | * Perform flow control to the driver. For PTY/TTY pairs we | |
beb7dd86 | 1725 | * must also propagate the TIOCKPKT status. May be called |
af9b897e AC |
1726 | * on an already stopped device and will not re-call the driver |
1727 | * method. | |
1728 | * | |
1729 | * This functionality is used by both the line disciplines for | |
1730 | * halting incoming flow and by the driver. It may therefore be | |
1731 | * called from any context, may be under the tty atomic_write_lock | |
1732 | * but not always. | |
1733 | * | |
1734 | * Locking: | |
04f378b1 | 1735 | * Uses the tty control lock internally |
af9b897e AC |
1736 | */ |
1737 | ||
1da177e4 LT |
1738 | void stop_tty(struct tty_struct *tty) |
1739 | { | |
04f378b1 AC |
1740 | unsigned long flags; |
1741 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
1742 | if (tty->stopped) { | |
1743 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
1da177e4 | 1744 | return; |
04f378b1 | 1745 | } |
1da177e4 LT |
1746 | tty->stopped = 1; |
1747 | if (tty->link && tty->link->packet) { | |
1748 | tty->ctrl_status &= ~TIOCPKT_START; | |
1749 | tty->ctrl_status |= TIOCPKT_STOP; | |
1750 | wake_up_interruptible(&tty->link->read_wait); | |
1751 | } | |
04f378b1 | 1752 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
f34d7a5b AC |
1753 | if (tty->ops->stop) |
1754 | (tty->ops->stop)(tty); | |
1da177e4 LT |
1755 | } |
1756 | ||
1757 | EXPORT_SYMBOL(stop_tty); | |
1758 | ||
af9b897e | 1759 | /** |
beb7dd86 | 1760 | * start_tty - propagate flow control |
af9b897e AC |
1761 | * @tty: tty to start |
1762 | * | |
1763 | * Start a tty that has been stopped if at all possible. Perform | |
3a4fa0a2 | 1764 | * any necessary wakeups and propagate the TIOCPKT status. If this |
af9b897e AC |
1765 | * is the tty was previous stopped and is being started then the |
1766 | * driver start method is invoked and the line discipline woken. | |
1767 | * | |
1768 | * Locking: | |
04f378b1 | 1769 | * ctrl_lock |
af9b897e AC |
1770 | */ |
1771 | ||
1da177e4 LT |
1772 | void start_tty(struct tty_struct *tty) |
1773 | { | |
04f378b1 AC |
1774 | unsigned long flags; |
1775 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
1776 | if (!tty->stopped || tty->flow_stopped) { | |
1777 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
1da177e4 | 1778 | return; |
04f378b1 | 1779 | } |
1da177e4 LT |
1780 | tty->stopped = 0; |
1781 | if (tty->link && tty->link->packet) { | |
1782 | tty->ctrl_status &= ~TIOCPKT_STOP; | |
1783 | tty->ctrl_status |= TIOCPKT_START; | |
1784 | wake_up_interruptible(&tty->link->read_wait); | |
1785 | } | |
04f378b1 | 1786 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
f34d7a5b AC |
1787 | if (tty->ops->start) |
1788 | (tty->ops->start)(tty); | |
1da177e4 LT |
1789 | /* If we have a running line discipline it may need kicking */ |
1790 | tty_wakeup(tty); | |
1da177e4 LT |
1791 | } |
1792 | ||
1793 | EXPORT_SYMBOL(start_tty); | |
1794 | ||
af9b897e AC |
1795 | /** |
1796 | * tty_read - read method for tty device files | |
1797 | * @file: pointer to tty file | |
1798 | * @buf: user buffer | |
1799 | * @count: size of user buffer | |
1800 | * @ppos: unused | |
1801 | * | |
1802 | * Perform the read system call function on this terminal device. Checks | |
1803 | * for hung up devices before calling the line discipline method. | |
1804 | * | |
1805 | * Locking: | |
47f86834 AC |
1806 | * Locks the line discipline internally while needed. Multiple |
1807 | * read calls may be outstanding in parallel. | |
af9b897e AC |
1808 | */ |
1809 | ||
37bdfb07 | 1810 | static ssize_t tty_read(struct file *file, char __user *buf, size_t count, |
1da177e4 LT |
1811 | loff_t *ppos) |
1812 | { | |
1813 | int i; | |
37bdfb07 | 1814 | struct tty_struct *tty; |
1da177e4 LT |
1815 | struct inode *inode; |
1816 | struct tty_ldisc *ld; | |
1817 | ||
1818 | tty = (struct tty_struct *)file->private_data; | |
a7113a96 | 1819 | inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1820 | if (tty_paranoia_check(tty, inode, "tty_read")) |
1821 | return -EIO; | |
1822 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) | |
1823 | return -EIO; | |
1824 | ||
1825 | /* We want to wait for the line discipline to sort out in this | |
1826 | situation */ | |
1827 | ld = tty_ldisc_ref_wait(tty); | |
1da177e4 | 1828 | if (ld->read) |
37bdfb07 | 1829 | i = (ld->read)(tty, file, buf, count); |
1da177e4 LT |
1830 | else |
1831 | i = -EIO; | |
1832 | tty_ldisc_deref(ld); | |
1da177e4 LT |
1833 | if (i > 0) |
1834 | inode->i_atime = current_fs_time(inode->i_sb); | |
1835 | return i; | |
1836 | } | |
1837 | ||
9c1729db AC |
1838 | void tty_write_unlock(struct tty_struct *tty) |
1839 | { | |
1840 | mutex_unlock(&tty->atomic_write_lock); | |
1841 | wake_up_interruptible(&tty->write_wait); | |
1842 | } | |
1843 | ||
1844 | int tty_write_lock(struct tty_struct *tty, int ndelay) | |
1845 | { | |
1846 | if (!mutex_trylock(&tty->atomic_write_lock)) { | |
1847 | if (ndelay) | |
1848 | return -EAGAIN; | |
1849 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) | |
1850 | return -ERESTARTSYS; | |
1851 | } | |
1852 | return 0; | |
1853 | } | |
1854 | ||
1da177e4 LT |
1855 | /* |
1856 | * Split writes up in sane blocksizes to avoid | |
1857 | * denial-of-service type attacks | |
1858 | */ | |
1859 | static inline ssize_t do_tty_write( | |
1860 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), | |
1861 | struct tty_struct *tty, | |
1862 | struct file *file, | |
1863 | const char __user *buf, | |
1864 | size_t count) | |
1865 | { | |
9c1729db | 1866 | ssize_t ret, written = 0; |
1da177e4 | 1867 | unsigned int chunk; |
37bdfb07 | 1868 | |
9c1729db AC |
1869 | ret = tty_write_lock(tty, file->f_flags & O_NDELAY); |
1870 | if (ret < 0) | |
1871 | return ret; | |
1da177e4 LT |
1872 | |
1873 | /* | |
1874 | * We chunk up writes into a temporary buffer. This | |
1875 | * simplifies low-level drivers immensely, since they | |
1876 | * don't have locking issues and user mode accesses. | |
1877 | * | |
1878 | * But if TTY_NO_WRITE_SPLIT is set, we should use a | |
1879 | * big chunk-size.. | |
1880 | * | |
1881 | * The default chunk-size is 2kB, because the NTTY | |
1882 | * layer has problems with bigger chunks. It will | |
1883 | * claim to be able to handle more characters than | |
1884 | * it actually does. | |
af9b897e AC |
1885 | * |
1886 | * FIXME: This can probably go away now except that 64K chunks | |
1887 | * are too likely to fail unless switched to vmalloc... | |
1da177e4 LT |
1888 | */ |
1889 | chunk = 2048; | |
1890 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) | |
1891 | chunk = 65536; | |
1892 | if (count < chunk) | |
1893 | chunk = count; | |
1894 | ||
70522e12 | 1895 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
1da177e4 LT |
1896 | if (tty->write_cnt < chunk) { |
1897 | unsigned char *buf; | |
1898 | ||
1899 | if (chunk < 1024) | |
1900 | chunk = 1024; | |
1901 | ||
1902 | buf = kmalloc(chunk, GFP_KERNEL); | |
1903 | if (!buf) { | |
9c1729db AC |
1904 | ret = -ENOMEM; |
1905 | goto out; | |
1da177e4 LT |
1906 | } |
1907 | kfree(tty->write_buf); | |
1908 | tty->write_cnt = chunk; | |
1909 | tty->write_buf = buf; | |
1910 | } | |
1911 | ||
1912 | /* Do the write .. */ | |
1913 | for (;;) { | |
1914 | size_t size = count; | |
1915 | if (size > chunk) | |
1916 | size = chunk; | |
1917 | ret = -EFAULT; | |
1918 | if (copy_from_user(tty->write_buf, buf, size)) | |
1919 | break; | |
1da177e4 | 1920 | ret = write(tty, file, tty->write_buf, size); |
1da177e4 LT |
1921 | if (ret <= 0) |
1922 | break; | |
1923 | written += ret; | |
1924 | buf += ret; | |
1925 | count -= ret; | |
1926 | if (!count) | |
1927 | break; | |
1928 | ret = -ERESTARTSYS; | |
1929 | if (signal_pending(current)) | |
1930 | break; | |
1931 | cond_resched(); | |
1932 | } | |
1933 | if (written) { | |
a7113a96 | 1934 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1935 | inode->i_mtime = current_fs_time(inode->i_sb); |
1936 | ret = written; | |
1937 | } | |
9c1729db AC |
1938 | out: |
1939 | tty_write_unlock(tty); | |
1da177e4 LT |
1940 | return ret; |
1941 | } | |
1942 | ||
1943 | ||
af9b897e AC |
1944 | /** |
1945 | * tty_write - write method for tty device file | |
1946 | * @file: tty file pointer | |
1947 | * @buf: user data to write | |
1948 | * @count: bytes to write | |
1949 | * @ppos: unused | |
1950 | * | |
1951 | * Write data to a tty device via the line discipline. | |
1952 | * | |
1953 | * Locking: | |
1954 | * Locks the line discipline as required | |
1955 | * Writes to the tty driver are serialized by the atomic_write_lock | |
1956 | * and are then processed in chunks to the device. The line discipline | |
1957 | * write method will not be involked in parallel for each device | |
1958 | * The line discipline write method is called under the big | |
1959 | * kernel lock for historical reasons. New code should not rely on this. | |
1960 | */ | |
1961 | ||
37bdfb07 AC |
1962 | static ssize_t tty_write(struct file *file, const char __user *buf, |
1963 | size_t count, loff_t *ppos) | |
1da177e4 | 1964 | { |
37bdfb07 | 1965 | struct tty_struct *tty; |
a7113a96 | 1966 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1967 | ssize_t ret; |
1968 | struct tty_ldisc *ld; | |
37bdfb07 | 1969 | |
1da177e4 LT |
1970 | tty = (struct tty_struct *)file->private_data; |
1971 | if (tty_paranoia_check(tty, inode, "tty_write")) | |
1972 | return -EIO; | |
f34d7a5b | 1973 | if (!tty || !tty->ops->write || |
37bdfb07 AC |
1974 | (test_bit(TTY_IO_ERROR, &tty->flags))) |
1975 | return -EIO; | |
f34d7a5b AC |
1976 | /* Short term debug to catch buggy drivers */ |
1977 | if (tty->ops->write_room == NULL) | |
1978 | printk(KERN_ERR "tty driver %s lacks a write_room method.\n", | |
1979 | tty->driver->name); | |
37bdfb07 | 1980 | ld = tty_ldisc_ref_wait(tty); |
1da177e4 LT |
1981 | if (!ld->write) |
1982 | ret = -EIO; | |
1983 | else | |
1984 | ret = do_tty_write(ld->write, tty, file, buf, count); | |
1985 | tty_ldisc_deref(ld); | |
1986 | return ret; | |
1987 | } | |
1988 | ||
37bdfb07 AC |
1989 | ssize_t redirected_tty_write(struct file *file, const char __user *buf, |
1990 | size_t count, loff_t *ppos) | |
1da177e4 LT |
1991 | { |
1992 | struct file *p = NULL; | |
1993 | ||
1994 | spin_lock(&redirect_lock); | |
1995 | if (redirect) { | |
1996 | get_file(redirect); | |
1997 | p = redirect; | |
1998 | } | |
1999 | spin_unlock(&redirect_lock); | |
2000 | ||
2001 | if (p) { | |
2002 | ssize_t res; | |
2003 | res = vfs_write(p, buf, count, &p->f_pos); | |
2004 | fput(p); | |
2005 | return res; | |
2006 | } | |
1da177e4 LT |
2007 | return tty_write(file, buf, count, ppos); |
2008 | } | |
2009 | ||
2010 | static char ptychar[] = "pqrstuvwxyzabcde"; | |
2011 | ||
af9b897e AC |
2012 | /** |
2013 | * pty_line_name - generate name for a pty | |
2014 | * @driver: the tty driver in use | |
2015 | * @index: the minor number | |
2016 | * @p: output buffer of at least 6 bytes | |
2017 | * | |
2018 | * Generate a name from a driver reference and write it to the output | |
2019 | * buffer. | |
2020 | * | |
2021 | * Locking: None | |
2022 | */ | |
2023 | static void pty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
2024 | { |
2025 | int i = index + driver->name_base; | |
2026 | /* ->name is initialized to "ttyp", but "tty" is expected */ | |
2027 | sprintf(p, "%s%c%x", | |
37bdfb07 AC |
2028 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, |
2029 | ptychar[i >> 4 & 0xf], i & 0xf); | |
1da177e4 LT |
2030 | } |
2031 | ||
af9b897e AC |
2032 | /** |
2033 | * pty_line_name - generate name for a tty | |
2034 | * @driver: the tty driver in use | |
2035 | * @index: the minor number | |
2036 | * @p: output buffer of at least 7 bytes | |
2037 | * | |
2038 | * Generate a name from a driver reference and write it to the output | |
2039 | * buffer. | |
2040 | * | |
2041 | * Locking: None | |
2042 | */ | |
2043 | static void tty_line_name(struct tty_driver *driver, int index, char *p) | |
1da177e4 LT |
2044 | { |
2045 | sprintf(p, "%s%d", driver->name, index + driver->name_base); | |
2046 | } | |
2047 | ||
af9b897e AC |
2048 | /** |
2049 | * init_dev - initialise a tty device | |
2050 | * @driver: tty driver we are opening a device on | |
2051 | * @idx: device index | |
2052 | * @tty: returned tty structure | |
2053 | * | |
2054 | * Prepare a tty device. This may not be a "new" clean device but | |
2055 | * could also be an active device. The pty drivers require special | |
2056 | * handling because of this. | |
2057 | * | |
2058 | * Locking: | |
2059 | * The function is called under the tty_mutex, which | |
2060 | * protects us from the tty struct or driver itself going away. | |
2061 | * | |
2062 | * On exit the tty device has the line discipline attached and | |
2063 | * a reference count of 1. If a pair was created for pty/tty use | |
2064 | * and the other was a pty master then it too has a reference count of 1. | |
2065 | * | |
1da177e4 | 2066 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
70522e12 IM |
2067 | * failed open. The new code protects the open with a mutex, so it's |
2068 | * really quite straightforward. The mutex locking can probably be | |
1da177e4 LT |
2069 | * relaxed for the (most common) case of reopening a tty. |
2070 | */ | |
af9b897e | 2071 | |
1da177e4 LT |
2072 | static int init_dev(struct tty_driver *driver, int idx, |
2073 | struct tty_struct **ret_tty) | |
2074 | { | |
2075 | struct tty_struct *tty, *o_tty; | |
edc6afc5 AC |
2076 | struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; |
2077 | struct ktermios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; | |
af9b897e | 2078 | int retval = 0; |
1da177e4 LT |
2079 | |
2080 | /* check whether we're reopening an existing tty */ | |
2081 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2082 | tty = devpts_get_tty(idx); | |
5a39e8c6 ASRF |
2083 | /* |
2084 | * If we don't have a tty here on a slave open, it's because | |
2085 | * the master already started the close process and there's | |
2086 | * no relation between devpts file and tty anymore. | |
2087 | */ | |
2088 | if (!tty && driver->subtype == PTY_TYPE_SLAVE) { | |
2089 | retval = -EIO; | |
2090 | goto end_init; | |
2091 | } | |
2092 | /* | |
2093 | * It's safe from now on because init_dev() is called with | |
2094 | * tty_mutex held and release_dev() won't change tty->count | |
2095 | * or tty->flags without having to grab tty_mutex | |
2096 | */ | |
1da177e4 LT |
2097 | if (tty && driver->subtype == PTY_TYPE_MASTER) |
2098 | tty = tty->link; | |
2099 | } else { | |
2100 | tty = driver->ttys[idx]; | |
2101 | } | |
2102 | if (tty) goto fast_track; | |
2103 | ||
2104 | /* | |
2105 | * First time open is complex, especially for PTY devices. | |
2106 | * This code guarantees that either everything succeeds and the | |
2107 | * TTY is ready for operation, or else the table slots are vacated | |
37bdfb07 | 2108 | * and the allocated memory released. (Except that the termios |
1da177e4 LT |
2109 | * and locked termios may be retained.) |
2110 | */ | |
2111 | ||
2112 | if (!try_module_get(driver->owner)) { | |
2113 | retval = -ENODEV; | |
2114 | goto end_init; | |
2115 | } | |
2116 | ||
2117 | o_tty = NULL; | |
2118 | tp = o_tp = NULL; | |
2119 | ltp = o_ltp = NULL; | |
2120 | ||
2121 | tty = alloc_tty_struct(); | |
37bdfb07 | 2122 | if (!tty) |
1da177e4 LT |
2123 | goto fail_no_mem; |
2124 | initialize_tty_struct(tty); | |
2125 | tty->driver = driver; | |
f34d7a5b | 2126 | tty->ops = driver->ops; |
1da177e4 LT |
2127 | tty->index = idx; |
2128 | tty_line_name(driver, idx, tty->name); | |
2129 | ||
2130 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2131 | tp_loc = &tty->termios; | |
2132 | ltp_loc = &tty->termios_locked; | |
2133 | } else { | |
2134 | tp_loc = &driver->termios[idx]; | |
2135 | ltp_loc = &driver->termios_locked[idx]; | |
2136 | } | |
2137 | ||
2138 | if (!*tp_loc) { | |
abcb1ff3 | 2139 | tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2140 | if (!tp) |
2141 | goto free_mem_out; | |
2142 | *tp = driver->init_termios; | |
2143 | } | |
2144 | ||
2145 | if (!*ltp_loc) { | |
506eb99a | 2146 | ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2147 | if (!ltp) |
2148 | goto free_mem_out; | |
1da177e4 LT |
2149 | } |
2150 | ||
2151 | if (driver->type == TTY_DRIVER_TYPE_PTY) { | |
2152 | o_tty = alloc_tty_struct(); | |
2153 | if (!o_tty) | |
2154 | goto free_mem_out; | |
2155 | initialize_tty_struct(o_tty); | |
2156 | o_tty->driver = driver->other; | |
f34d7a5b | 2157 | o_tty->ops = driver->ops; |
1da177e4 LT |
2158 | o_tty->index = idx; |
2159 | tty_line_name(driver->other, idx, o_tty->name); | |
2160 | ||
2161 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { | |
2162 | o_tp_loc = &o_tty->termios; | |
2163 | o_ltp_loc = &o_tty->termios_locked; | |
2164 | } else { | |
2165 | o_tp_loc = &driver->other->termios[idx]; | |
2166 | o_ltp_loc = &driver->other->termios_locked[idx]; | |
2167 | } | |
2168 | ||
2169 | if (!*o_tp_loc) { | |
abcb1ff3 | 2170 | o_tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2171 | if (!o_tp) |
2172 | goto free_mem_out; | |
2173 | *o_tp = driver->other->init_termios; | |
2174 | } | |
2175 | ||
2176 | if (!*o_ltp_loc) { | |
506eb99a | 2177 | o_ltp = kzalloc(sizeof(struct ktermios), GFP_KERNEL); |
1da177e4 LT |
2178 | if (!o_ltp) |
2179 | goto free_mem_out; | |
1da177e4 LT |
2180 | } |
2181 | ||
2182 | /* | |
2183 | * Everything allocated ... set up the o_tty structure. | |
2184 | */ | |
37bdfb07 | 2185 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) |
1da177e4 | 2186 | driver->other->ttys[idx] = o_tty; |
1da177e4 LT |
2187 | if (!*o_tp_loc) |
2188 | *o_tp_loc = o_tp; | |
2189 | if (!*o_ltp_loc) | |
2190 | *o_ltp_loc = o_ltp; | |
2191 | o_tty->termios = *o_tp_loc; | |
2192 | o_tty->termios_locked = *o_ltp_loc; | |
2193 | driver->other->refcount++; | |
2194 | if (driver->subtype == PTY_TYPE_MASTER) | |
2195 | o_tty->count++; | |
2196 | ||
2197 | /* Establish the links in both directions */ | |
2198 | tty->link = o_tty; | |
2199 | o_tty->link = tty; | |
2200 | } | |
2201 | ||
37bdfb07 | 2202 | /* |
1da177e4 | 2203 | * All structures have been allocated, so now we install them. |
d5698c28 | 2204 | * Failures after this point use release_tty to clean up, so |
1da177e4 LT |
2205 | * there's no need to null out the local pointers. |
2206 | */ | |
37bdfb07 | 2207 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) |
1da177e4 | 2208 | driver->ttys[idx] = tty; |
37bdfb07 | 2209 | |
1da177e4 LT |
2210 | if (!*tp_loc) |
2211 | *tp_loc = tp; | |
2212 | if (!*ltp_loc) | |
2213 | *ltp_loc = ltp; | |
2214 | tty->termios = *tp_loc; | |
2215 | tty->termios_locked = *ltp_loc; | |
edc6afc5 AC |
2216 | /* Compatibility until drivers always set this */ |
2217 | tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios); | |
2218 | tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios); | |
1da177e4 LT |
2219 | driver->refcount++; |
2220 | tty->count++; | |
2221 | ||
37bdfb07 | 2222 | /* |
1da177e4 | 2223 | * Structures all installed ... call the ldisc open routines. |
d5698c28 CH |
2224 | * If we fail here just call release_tty to clean up. No need |
2225 | * to decrement the use counts, as release_tty doesn't care. | |
1da177e4 LT |
2226 | */ |
2227 | ||
2228 | if (tty->ldisc.open) { | |
2229 | retval = (tty->ldisc.open)(tty); | |
2230 | if (retval) | |
2231 | goto release_mem_out; | |
2232 | } | |
2233 | if (o_tty && o_tty->ldisc.open) { | |
2234 | retval = (o_tty->ldisc.open)(o_tty); | |
2235 | if (retval) { | |
2236 | if (tty->ldisc.close) | |
2237 | (tty->ldisc.close)(tty); | |
2238 | goto release_mem_out; | |
2239 | } | |
2240 | tty_ldisc_enable(o_tty); | |
2241 | } | |
2242 | tty_ldisc_enable(tty); | |
2243 | goto success; | |
2244 | ||
2245 | /* | |
2246 | * This fast open can be used if the tty is already open. | |
2247 | * No memory is allocated, and the only failures are from | |
2248 | * attempting to open a closing tty or attempting multiple | |
2249 | * opens on a pty master. | |
2250 | */ | |
2251 | fast_track: | |
2252 | if (test_bit(TTY_CLOSING, &tty->flags)) { | |
2253 | retval = -EIO; | |
2254 | goto end_init; | |
2255 | } | |
2256 | if (driver->type == TTY_DRIVER_TYPE_PTY && | |
2257 | driver->subtype == PTY_TYPE_MASTER) { | |
2258 | /* | |
37bdfb07 | 2259 | * special case for PTY masters: only one open permitted, |
1da177e4 LT |
2260 | * and the slave side open count is incremented as well. |
2261 | */ | |
2262 | if (tty->count) { | |
2263 | retval = -EIO; | |
2264 | goto end_init; | |
2265 | } | |
2266 | tty->link->count++; | |
2267 | } | |
2268 | tty->count++; | |
2269 | tty->driver = driver; /* N.B. why do this every time?? */ | |
2270 | ||
2271 | /* FIXME */ | |
37bdfb07 | 2272 | if (!test_bit(TTY_LDISC, &tty->flags)) |
1da177e4 LT |
2273 | printk(KERN_ERR "init_dev but no ldisc\n"); |
2274 | success: | |
2275 | *ret_tty = tty; | |
37bdfb07 | 2276 | |
70522e12 | 2277 | /* All paths come through here to release the mutex */ |
1da177e4 LT |
2278 | end_init: |
2279 | return retval; | |
2280 | ||
2281 | /* Release locally allocated memory ... nothing placed in slots */ | |
2282 | free_mem_out: | |
735d5661 | 2283 | kfree(o_tp); |
1da177e4 LT |
2284 | if (o_tty) |
2285 | free_tty_struct(o_tty); | |
735d5661 JJ |
2286 | kfree(ltp); |
2287 | kfree(tp); | |
1da177e4 LT |
2288 | free_tty_struct(tty); |
2289 | ||
2290 | fail_no_mem: | |
2291 | module_put(driver->owner); | |
2292 | retval = -ENOMEM; | |
2293 | goto end_init; | |
2294 | ||
d5698c28 | 2295 | /* call the tty release_tty routine to clean out this slot */ |
1da177e4 | 2296 | release_mem_out: |
4050914f AM |
2297 | if (printk_ratelimit()) |
2298 | printk(KERN_INFO "init_dev: ldisc open failed, " | |
2299 | "clearing slot %d\n", idx); | |
d5698c28 | 2300 | release_tty(tty, idx); |
1da177e4 LT |
2301 | goto end_init; |
2302 | } | |
2303 | ||
af9b897e | 2304 | /** |
d5698c28 | 2305 | * release_one_tty - release tty structure memory |
af9b897e AC |
2306 | * |
2307 | * Releases memory associated with a tty structure, and clears out the | |
2308 | * driver table slots. This function is called when a device is no longer | |
2309 | * in use. It also gets called when setup of a device fails. | |
2310 | * | |
2311 | * Locking: | |
2312 | * tty_mutex - sometimes only | |
2313 | * takes the file list lock internally when working on the list | |
2314 | * of ttys that the driver keeps. | |
2315 | * FIXME: should we require tty_mutex is held here ?? | |
1da177e4 | 2316 | */ |
d5698c28 | 2317 | static void release_one_tty(struct tty_struct *tty, int idx) |
1da177e4 | 2318 | { |
1da177e4 | 2319 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
d5698c28 | 2320 | struct ktermios *tp; |
1da177e4 LT |
2321 | |
2322 | if (!devpts) | |
2323 | tty->driver->ttys[idx] = NULL; | |
d5698c28 | 2324 | |
1da177e4 LT |
2325 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
2326 | tp = tty->termios; | |
2327 | if (!devpts) | |
2328 | tty->driver->termios[idx] = NULL; | |
2329 | kfree(tp); | |
2330 | ||
2331 | tp = tty->termios_locked; | |
2332 | if (!devpts) | |
2333 | tty->driver->termios_locked[idx] = NULL; | |
2334 | kfree(tp); | |
2335 | } | |
2336 | ||
d5698c28 | 2337 | |
1da177e4 LT |
2338 | tty->magic = 0; |
2339 | tty->driver->refcount--; | |
d5698c28 | 2340 | |
1da177e4 LT |
2341 | file_list_lock(); |
2342 | list_del_init(&tty->tty_files); | |
2343 | file_list_unlock(); | |
d5698c28 | 2344 | |
1da177e4 LT |
2345 | free_tty_struct(tty); |
2346 | } | |
2347 | ||
d5698c28 CH |
2348 | /** |
2349 | * release_tty - release tty structure memory | |
2350 | * | |
2351 | * Release both @tty and a possible linked partner (think pty pair), | |
2352 | * and decrement the refcount of the backing module. | |
2353 | * | |
2354 | * Locking: | |
2355 | * tty_mutex - sometimes only | |
2356 | * takes the file list lock internally when working on the list | |
2357 | * of ttys that the driver keeps. | |
2358 | * FIXME: should we require tty_mutex is held here ?? | |
2359 | */ | |
2360 | static void release_tty(struct tty_struct *tty, int idx) | |
2361 | { | |
2362 | struct tty_driver *driver = tty->driver; | |
2363 | ||
2364 | if (tty->link) | |
2365 | release_one_tty(tty->link, idx); | |
2366 | release_one_tty(tty, idx); | |
2367 | module_put(driver->owner); | |
2368 | } | |
2369 | ||
1da177e4 LT |
2370 | /* |
2371 | * Even releasing the tty structures is a tricky business.. We have | |
2372 | * to be very careful that the structures are all released at the | |
2373 | * same time, as interrupts might otherwise get the wrong pointers. | |
2374 | * | |
2375 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could | |
2376 | * lead to double frees or releasing memory still in use. | |
2377 | */ | |
37bdfb07 | 2378 | static void release_dev(struct file *filp) |
1da177e4 LT |
2379 | { |
2380 | struct tty_struct *tty, *o_tty; | |
2381 | int pty_master, tty_closing, o_tty_closing, do_sleep; | |
14a6283e | 2382 | int devpts; |
1da177e4 LT |
2383 | int idx; |
2384 | char buf[64]; | |
2385 | unsigned long flags; | |
37bdfb07 | 2386 | |
1da177e4 | 2387 | tty = (struct tty_struct *)filp->private_data; |
37bdfb07 AC |
2388 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, |
2389 | "release_dev")) | |
1da177e4 LT |
2390 | return; |
2391 | ||
2392 | check_tty_count(tty, "release_dev"); | |
2393 | ||
2394 | tty_fasync(-1, filp, 0); | |
2395 | ||
2396 | idx = tty->index; | |
2397 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2398 | tty->driver->subtype == PTY_TYPE_MASTER); | |
2399 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; | |
1da177e4 LT |
2400 | o_tty = tty->link; |
2401 | ||
2402 | #ifdef TTY_PARANOIA_CHECK | |
2403 | if (idx < 0 || idx >= tty->driver->num) { | |
2404 | printk(KERN_DEBUG "release_dev: bad idx when trying to " | |
2405 | "free (%s)\n", tty->name); | |
2406 | return; | |
2407 | } | |
2408 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2409 | if (tty != tty->driver->ttys[idx]) { | |
2410 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " | |
2411 | "for (%s)\n", idx, tty->name); | |
2412 | return; | |
2413 | } | |
2414 | if (tty->termios != tty->driver->termios[idx]) { | |
2415 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " | |
2416 | "for (%s)\n", | |
2417 | idx, tty->name); | |
2418 | return; | |
2419 | } | |
2420 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { | |
2421 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " | |
2422 | "termios_locked for (%s)\n", | |
2423 | idx, tty->name); | |
2424 | return; | |
2425 | } | |
2426 | } | |
2427 | #endif | |
2428 | ||
2429 | #ifdef TTY_DEBUG_HANGUP | |
2430 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", | |
2431 | tty_name(tty, buf), tty->count); | |
2432 | #endif | |
2433 | ||
2434 | #ifdef TTY_PARANOIA_CHECK | |
2435 | if (tty->driver->other && | |
2436 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { | |
2437 | if (o_tty != tty->driver->other->ttys[idx]) { | |
2438 | printk(KERN_DEBUG "release_dev: other->table[%d] " | |
2439 | "not o_tty for (%s)\n", | |
2440 | idx, tty->name); | |
2441 | return; | |
2442 | } | |
2443 | if (o_tty->termios != tty->driver->other->termios[idx]) { | |
2444 | printk(KERN_DEBUG "release_dev: other->termios[%d] " | |
2445 | "not o_termios for (%s)\n", | |
2446 | idx, tty->name); | |
2447 | return; | |
2448 | } | |
37bdfb07 | 2449 | if (o_tty->termios_locked != |
1da177e4 LT |
2450 | tty->driver->other->termios_locked[idx]) { |
2451 | printk(KERN_DEBUG "release_dev: other->termios_locked[" | |
2452 | "%d] not o_termios_locked for (%s)\n", | |
2453 | idx, tty->name); | |
2454 | return; | |
2455 | } | |
2456 | if (o_tty->link != tty) { | |
2457 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); | |
2458 | return; | |
2459 | } | |
2460 | } | |
2461 | #endif | |
f34d7a5b AC |
2462 | if (tty->ops->close) |
2463 | tty->ops->close(tty, filp); | |
1da177e4 LT |
2464 | |
2465 | /* | |
2466 | * Sanity check: if tty->count is going to zero, there shouldn't be | |
2467 | * any waiters on tty->read_wait or tty->write_wait. We test the | |
2468 | * wait queues and kick everyone out _before_ actually starting to | |
2469 | * close. This ensures that we won't block while releasing the tty | |
2470 | * structure. | |
2471 | * | |
2472 | * The test for the o_tty closing is necessary, since the master and | |
2473 | * slave sides may close in any order. If the slave side closes out | |
2474 | * first, its count will be one, since the master side holds an open. | |
2475 | * Thus this test wouldn't be triggered at the time the slave closes, | |
2476 | * so we do it now. | |
2477 | * | |
2478 | * Note that it's possible for the tty to be opened again while we're | |
2479 | * flushing out waiters. By recalculating the closing flags before | |
2480 | * each iteration we avoid any problems. | |
2481 | */ | |
2482 | while (1) { | |
2483 | /* Guard against races with tty->count changes elsewhere and | |
2484 | opens on /dev/tty */ | |
37bdfb07 | 2485 | |
70522e12 | 2486 | mutex_lock(&tty_mutex); |
1da177e4 LT |
2487 | tty_closing = tty->count <= 1; |
2488 | o_tty_closing = o_tty && | |
2489 | (o_tty->count <= (pty_master ? 1 : 0)); | |
1da177e4 LT |
2490 | do_sleep = 0; |
2491 | ||
2492 | if (tty_closing) { | |
2493 | if (waitqueue_active(&tty->read_wait)) { | |
2494 | wake_up(&tty->read_wait); | |
2495 | do_sleep++; | |
2496 | } | |
2497 | if (waitqueue_active(&tty->write_wait)) { | |
2498 | wake_up(&tty->write_wait); | |
2499 | do_sleep++; | |
2500 | } | |
2501 | } | |
2502 | if (o_tty_closing) { | |
2503 | if (waitqueue_active(&o_tty->read_wait)) { | |
2504 | wake_up(&o_tty->read_wait); | |
2505 | do_sleep++; | |
2506 | } | |
2507 | if (waitqueue_active(&o_tty->write_wait)) { | |
2508 | wake_up(&o_tty->write_wait); | |
2509 | do_sleep++; | |
2510 | } | |
2511 | } | |
2512 | if (!do_sleep) | |
2513 | break; | |
2514 | ||
2515 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " | |
2516 | "active!\n", tty_name(tty, buf)); | |
70522e12 | 2517 | mutex_unlock(&tty_mutex); |
1da177e4 | 2518 | schedule(); |
37bdfb07 | 2519 | } |
1da177e4 LT |
2520 | |
2521 | /* | |
37bdfb07 AC |
2522 | * The closing flags are now consistent with the open counts on |
2523 | * both sides, and we've completed the last operation that could | |
1da177e4 LT |
2524 | * block, so it's safe to proceed with closing. |
2525 | */ | |
1da177e4 LT |
2526 | if (pty_master) { |
2527 | if (--o_tty->count < 0) { | |
2528 | printk(KERN_WARNING "release_dev: bad pty slave count " | |
2529 | "(%d) for %s\n", | |
2530 | o_tty->count, tty_name(o_tty, buf)); | |
2531 | o_tty->count = 0; | |
2532 | } | |
2533 | } | |
2534 | if (--tty->count < 0) { | |
2535 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", | |
2536 | tty->count, tty_name(tty, buf)); | |
2537 | tty->count = 0; | |
2538 | } | |
37bdfb07 | 2539 | |
1da177e4 LT |
2540 | /* |
2541 | * We've decremented tty->count, so we need to remove this file | |
2542 | * descriptor off the tty->tty_files list; this serves two | |
2543 | * purposes: | |
2544 | * - check_tty_count sees the correct number of file descriptors | |
2545 | * associated with this tty. | |
2546 | * - do_tty_hangup no longer sees this file descriptor as | |
2547 | * something that needs to be handled for hangups. | |
2548 | */ | |
2549 | file_kill(filp); | |
2550 | filp->private_data = NULL; | |
2551 | ||
2552 | /* | |
2553 | * Perform some housekeeping before deciding whether to return. | |
2554 | * | |
2555 | * Set the TTY_CLOSING flag if this was the last open. In the | |
2556 | * case of a pty we may have to wait around for the other side | |
2557 | * to close, and TTY_CLOSING makes sure we can't be reopened. | |
2558 | */ | |
37bdfb07 | 2559 | if (tty_closing) |
1da177e4 | 2560 | set_bit(TTY_CLOSING, &tty->flags); |
37bdfb07 | 2561 | if (o_tty_closing) |
1da177e4 LT |
2562 | set_bit(TTY_CLOSING, &o_tty->flags); |
2563 | ||
2564 | /* | |
2565 | * If _either_ side is closing, make sure there aren't any | |
2566 | * processes that still think tty or o_tty is their controlling | |
2567 | * tty. | |
2568 | */ | |
2569 | if (tty_closing || o_tty_closing) { | |
1da177e4 | 2570 | read_lock(&tasklist_lock); |
24ec839c | 2571 | session_clear_tty(tty->session); |
1da177e4 | 2572 | if (o_tty) |
24ec839c | 2573 | session_clear_tty(o_tty->session); |
1da177e4 LT |
2574 | read_unlock(&tasklist_lock); |
2575 | } | |
2576 | ||
70522e12 | 2577 | mutex_unlock(&tty_mutex); |
da965822 | 2578 | |
1da177e4 LT |
2579 | /* check whether both sides are closing ... */ |
2580 | if (!tty_closing || (o_tty && !o_tty_closing)) | |
2581 | return; | |
37bdfb07 | 2582 | |
1da177e4 LT |
2583 | #ifdef TTY_DEBUG_HANGUP |
2584 | printk(KERN_DEBUG "freeing tty structure..."); | |
2585 | #endif | |
2586 | /* | |
2587 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then | |
2588 | * kill any delayed work. As this is the final close it does not | |
2589 | * race with the set_ldisc code path. | |
2590 | */ | |
2591 | clear_bit(TTY_LDISC, &tty->flags); | |
33f0f88f | 2592 | cancel_delayed_work(&tty->buf.work); |
1da177e4 LT |
2593 | |
2594 | /* | |
33f0f88f | 2595 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
1da177e4 | 2596 | */ |
37bdfb07 | 2597 | |
1da177e4 | 2598 | flush_scheduled_work(); |
37bdfb07 | 2599 | |
1da177e4 LT |
2600 | /* |
2601 | * Wait for any short term users (we know they are just driver | |
2602 | * side waiters as the file is closing so user count on the file | |
2603 | * side is zero. | |
2604 | */ | |
2605 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
37bdfb07 | 2606 | while (tty->ldisc.refcount) { |
1da177e4 LT |
2607 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
2608 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); | |
2609 | spin_lock_irqsave(&tty_ldisc_lock, flags); | |
2610 | } | |
2611 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); | |
2612 | /* | |
2613 | * Shutdown the current line discipline, and reset it to N_TTY. | |
2614 | * N.B. why reset ldisc when we're releasing the memory?? | |
2615 | * | |
2616 | * FIXME: this MUST get fixed for the new reflocking | |
2617 | */ | |
2618 | if (tty->ldisc.close) | |
2619 | (tty->ldisc.close)(tty); | |
2620 | tty_ldisc_put(tty->ldisc.num); | |
37bdfb07 | 2621 | |
1da177e4 LT |
2622 | /* |
2623 | * Switch the line discipline back | |
2624 | */ | |
2625 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
37bdfb07 | 2626 | tty_set_termios_ldisc(tty, N_TTY); |
1da177e4 LT |
2627 | if (o_tty) { |
2628 | /* FIXME: could o_tty be in setldisc here ? */ | |
2629 | clear_bit(TTY_LDISC, &o_tty->flags); | |
2630 | if (o_tty->ldisc.close) | |
2631 | (o_tty->ldisc.close)(o_tty); | |
2632 | tty_ldisc_put(o_tty->ldisc.num); | |
2633 | tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); | |
37bdfb07 | 2634 | tty_set_termios_ldisc(o_tty, N_TTY); |
1da177e4 LT |
2635 | } |
2636 | /* | |
d5698c28 | 2637 | * The release_tty function takes care of the details of clearing |
1da177e4 LT |
2638 | * the slots and preserving the termios structure. |
2639 | */ | |
d5698c28 | 2640 | release_tty(tty, idx); |
1da177e4 | 2641 | |
1da177e4 | 2642 | /* Make this pty number available for reallocation */ |
718a9163 SB |
2643 | if (devpts) |
2644 | devpts_kill_index(idx); | |
1da177e4 LT |
2645 | } |
2646 | ||
af9b897e AC |
2647 | /** |
2648 | * tty_open - open a tty device | |
2649 | * @inode: inode of device file | |
2650 | * @filp: file pointer to tty | |
1da177e4 | 2651 | * |
af9b897e AC |
2652 | * tty_open and tty_release keep up the tty count that contains the |
2653 | * number of opens done on a tty. We cannot use the inode-count, as | |
2654 | * different inodes might point to the same tty. | |
1da177e4 | 2655 | * |
af9b897e AC |
2656 | * Open-counting is needed for pty masters, as well as for keeping |
2657 | * track of serial lines: DTR is dropped when the last close happens. | |
2658 | * (This is not done solely through tty->count, now. - Ted 1/27/92) | |
2659 | * | |
2660 | * The termios state of a pty is reset on first open so that | |
2661 | * settings don't persist across reuse. | |
2662 | * | |
24ec839c PZ |
2663 | * Locking: tty_mutex protects tty, get_tty_driver and init_dev work. |
2664 | * tty->count should protect the rest. | |
2665 | * ->siglock protects ->signal/->sighand | |
1da177e4 | 2666 | */ |
af9b897e | 2667 | |
37bdfb07 | 2668 | static int tty_open(struct inode *inode, struct file *filp) |
1da177e4 LT |
2669 | { |
2670 | struct tty_struct *tty; | |
2671 | int noctty, retval; | |
2672 | struct tty_driver *driver; | |
2673 | int index; | |
2674 | dev_t device = inode->i_rdev; | |
2675 | unsigned short saved_flags = filp->f_flags; | |
2676 | ||
2677 | nonseekable_open(inode, filp); | |
37bdfb07 | 2678 | |
1da177e4 LT |
2679 | retry_open: |
2680 | noctty = filp->f_flags & O_NOCTTY; | |
2681 | index = -1; | |
2682 | retval = 0; | |
37bdfb07 | 2683 | |
70522e12 | 2684 | mutex_lock(&tty_mutex); |
1da177e4 | 2685 | |
37bdfb07 | 2686 | if (device == MKDEV(TTYAUX_MAJOR, 0)) { |
24ec839c PZ |
2687 | tty = get_current_tty(); |
2688 | if (!tty) { | |
70522e12 | 2689 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2690 | return -ENXIO; |
2691 | } | |
24ec839c PZ |
2692 | driver = tty->driver; |
2693 | index = tty->index; | |
1da177e4 LT |
2694 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
2695 | /* noctty = 1; */ | |
2696 | goto got_driver; | |
2697 | } | |
2698 | #ifdef CONFIG_VT | |
37bdfb07 | 2699 | if (device == MKDEV(TTY_MAJOR, 0)) { |
1da177e4 LT |
2700 | extern struct tty_driver *console_driver; |
2701 | driver = console_driver; | |
2702 | index = fg_console; | |
2703 | noctty = 1; | |
2704 | goto got_driver; | |
2705 | } | |
2706 | #endif | |
37bdfb07 | 2707 | if (device == MKDEV(TTYAUX_MAJOR, 1)) { |
1da177e4 LT |
2708 | driver = console_device(&index); |
2709 | if (driver) { | |
2710 | /* Don't let /dev/console block */ | |
2711 | filp->f_flags |= O_NONBLOCK; | |
2712 | noctty = 1; | |
2713 | goto got_driver; | |
2714 | } | |
70522e12 | 2715 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2716 | return -ENODEV; |
2717 | } | |
2718 | ||
2719 | driver = get_tty_driver(device, &index); | |
2720 | if (!driver) { | |
70522e12 | 2721 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2722 | return -ENODEV; |
2723 | } | |
2724 | got_driver: | |
2725 | retval = init_dev(driver, index, &tty); | |
70522e12 | 2726 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
2727 | if (retval) |
2728 | return retval; | |
2729 | ||
2730 | filp->private_data = tty; | |
2731 | file_move(filp, &tty->tty_files); | |
2732 | check_tty_count(tty, "tty_open"); | |
2733 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
2734 | tty->driver->subtype == PTY_TYPE_MASTER) | |
2735 | noctty = 1; | |
2736 | #ifdef TTY_DEBUG_HANGUP | |
2737 | printk(KERN_DEBUG "opening %s...", tty->name); | |
2738 | #endif | |
2739 | if (!retval) { | |
f34d7a5b AC |
2740 | if (tty->ops->open) |
2741 | retval = tty->ops->open(tty, filp); | |
1da177e4 LT |
2742 | else |
2743 | retval = -ENODEV; | |
2744 | } | |
2745 | filp->f_flags = saved_flags; | |
2746 | ||
37bdfb07 AC |
2747 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && |
2748 | !capable(CAP_SYS_ADMIN)) | |
1da177e4 LT |
2749 | retval = -EBUSY; |
2750 | ||
2751 | if (retval) { | |
2752 | #ifdef TTY_DEBUG_HANGUP | |
2753 | printk(KERN_DEBUG "error %d in opening %s...", retval, | |
2754 | tty->name); | |
2755 | #endif | |
2756 | release_dev(filp); | |
2757 | if (retval != -ERESTARTSYS) | |
2758 | return retval; | |
2759 | if (signal_pending(current)) | |
2760 | return retval; | |
2761 | schedule(); | |
2762 | /* | |
2763 | * Need to reset f_op in case a hangup happened. | |
2764 | */ | |
2765 | if (filp->f_op == &hung_up_tty_fops) | |
2766 | filp->f_op = &tty_fops; | |
2767 | goto retry_open; | |
2768 | } | |
24ec839c PZ |
2769 | |
2770 | mutex_lock(&tty_mutex); | |
2771 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2772 | if (!noctty && |
2773 | current->signal->leader && | |
2774 | !current->signal->tty && | |
ab521dc0 | 2775 | tty->session == NULL) |
2a65f1d9 | 2776 | __proc_set_tty(current, tty); |
24ec839c PZ |
2777 | spin_unlock_irq(¤t->sighand->siglock); |
2778 | mutex_unlock(&tty_mutex); | |
1da177e4 LT |
2779 | return 0; |
2780 | } | |
2781 | ||
2782 | #ifdef CONFIG_UNIX98_PTYS | |
af9b897e AC |
2783 | /** |
2784 | * ptmx_open - open a unix 98 pty master | |
2785 | * @inode: inode of device file | |
2786 | * @filp: file pointer to tty | |
2787 | * | |
2788 | * Allocate a unix98 pty master device from the ptmx driver. | |
2789 | * | |
2790 | * Locking: tty_mutex protects theinit_dev work. tty->count should | |
37bdfb07 | 2791 | * protect the rest. |
af9b897e AC |
2792 | * allocated_ptys_lock handles the list of free pty numbers |
2793 | */ | |
2794 | ||
37bdfb07 | 2795 | static int ptmx_open(struct inode *inode, struct file *filp) |
1da177e4 LT |
2796 | { |
2797 | struct tty_struct *tty; | |
2798 | int retval; | |
2799 | int index; | |
1da177e4 LT |
2800 | |
2801 | nonseekable_open(inode, filp); | |
2802 | ||
2803 | /* find a device that is not in use. */ | |
718a9163 SB |
2804 | index = devpts_new_index(); |
2805 | if (index < 0) | |
2806 | return index; | |
1da177e4 | 2807 | |
70522e12 | 2808 | mutex_lock(&tty_mutex); |
1da177e4 | 2809 | retval = init_dev(ptm_driver, index, &tty); |
70522e12 | 2810 | mutex_unlock(&tty_mutex); |
37bdfb07 | 2811 | |
1da177e4 LT |
2812 | if (retval) |
2813 | goto out; | |
2814 | ||
2815 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ | |
2816 | filp->private_data = tty; | |
2817 | file_move(filp, &tty->tty_files); | |
2818 | ||
4f8f9d66 SB |
2819 | retval = devpts_pty_new(tty->link); |
2820 | if (retval) | |
1da177e4 LT |
2821 | goto out1; |
2822 | ||
86a96538 | 2823 | check_tty_count(tty, "ptmx_open"); |
f34d7a5b | 2824 | retval = ptm_driver->ops->open(tty, filp); |
41126226 | 2825 | if (!retval) |
1da177e4 LT |
2826 | return 0; |
2827 | out1: | |
2828 | release_dev(filp); | |
9453a5ad | 2829 | return retval; |
1da177e4 | 2830 | out: |
718a9163 | 2831 | devpts_kill_index(index); |
1da177e4 LT |
2832 | return retval; |
2833 | } | |
2834 | #endif | |
2835 | ||
af9b897e AC |
2836 | /** |
2837 | * tty_release - vfs callback for close | |
2838 | * @inode: inode of tty | |
2839 | * @filp: file pointer for handle to tty | |
2840 | * | |
2841 | * Called the last time each file handle is closed that references | |
2842 | * this tty. There may however be several such references. | |
2843 | * | |
2844 | * Locking: | |
2845 | * Takes bkl. See release_dev | |
2846 | */ | |
2847 | ||
37bdfb07 | 2848 | static int tty_release(struct inode *inode, struct file *filp) |
1da177e4 LT |
2849 | { |
2850 | lock_kernel(); | |
2851 | release_dev(filp); | |
2852 | unlock_kernel(); | |
2853 | return 0; | |
2854 | } | |
2855 | ||
af9b897e AC |
2856 | /** |
2857 | * tty_poll - check tty status | |
2858 | * @filp: file being polled | |
2859 | * @wait: poll wait structures to update | |
2860 | * | |
2861 | * Call the line discipline polling method to obtain the poll | |
2862 | * status of the device. | |
2863 | * | |
2864 | * Locking: locks called line discipline but ldisc poll method | |
2865 | * may be re-entered freely by other callers. | |
2866 | */ | |
2867 | ||
37bdfb07 | 2868 | static unsigned int tty_poll(struct file *filp, poll_table *wait) |
1da177e4 | 2869 | { |
37bdfb07 | 2870 | struct tty_struct *tty; |
1da177e4 LT |
2871 | struct tty_ldisc *ld; |
2872 | int ret = 0; | |
2873 | ||
2874 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2875 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll")) |
1da177e4 | 2876 | return 0; |
37bdfb07 | 2877 | |
1da177e4 LT |
2878 | ld = tty_ldisc_ref_wait(tty); |
2879 | if (ld->poll) | |
2880 | ret = (ld->poll)(tty, filp, wait); | |
2881 | tty_ldisc_deref(ld); | |
2882 | return ret; | |
2883 | } | |
2884 | ||
37bdfb07 | 2885 | static int tty_fasync(int fd, struct file *filp, int on) |
1da177e4 | 2886 | { |
37bdfb07 | 2887 | struct tty_struct *tty; |
47f86834 | 2888 | unsigned long flags; |
1da177e4 LT |
2889 | int retval; |
2890 | ||
2891 | tty = (struct tty_struct *)filp->private_data; | |
a7113a96 | 2892 | if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync")) |
1da177e4 | 2893 | return 0; |
37bdfb07 | 2894 | |
1da177e4 LT |
2895 | retval = fasync_helper(fd, filp, on, &tty->fasync); |
2896 | if (retval <= 0) | |
2897 | return retval; | |
2898 | ||
2899 | if (on) { | |
ab521dc0 EB |
2900 | enum pid_type type; |
2901 | struct pid *pid; | |
1da177e4 LT |
2902 | if (!waitqueue_active(&tty->read_wait)) |
2903 | tty->minimum_to_wake = 1; | |
47f86834 | 2904 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
ab521dc0 EB |
2905 | if (tty->pgrp) { |
2906 | pid = tty->pgrp; | |
2907 | type = PIDTYPE_PGID; | |
2908 | } else { | |
2909 | pid = task_pid(current); | |
2910 | type = PIDTYPE_PID; | |
2911 | } | |
47f86834 | 2912 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
ab521dc0 | 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; | |
47f86834 AC |
2998 | struct pid *pgrp, *rpgrp; |
2999 | unsigned long flags; | |
1da177e4 LT |
3000 | |
3001 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) | |
3002 | return -EFAULT; | |
ca9bda00 | 3003 | |
5785c95b | 3004 | mutex_lock(&tty->termios_mutex); |
1da177e4 | 3005 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
ca9bda00 AC |
3006 | goto done; |
3007 | ||
1da177e4 LT |
3008 | #ifdef CONFIG_VT |
3009 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { | |
5785c95b AV |
3010 | if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col, |
3011 | tmp_ws.ws_row)) { | |
3012 | mutex_unlock(&tty->termios_mutex); | |
37bdfb07 | 3013 | return -ENXIO; |
ca9bda00 | 3014 | } |
1da177e4 LT |
3015 | } |
3016 | #endif | |
47f86834 AC |
3017 | /* Get the PID values and reference them so we can |
3018 | avoid holding the tty ctrl lock while sending signals */ | |
3019 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
3020 | pgrp = get_pid(tty->pgrp); | |
3021 | rpgrp = get_pid(real_tty->pgrp); | |
3022 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
3023 | ||
3024 | if (pgrp) | |
3025 | kill_pgrp(pgrp, SIGWINCH, 1); | |
3026 | if (rpgrp != pgrp && rpgrp) | |
3027 | kill_pgrp(rpgrp, SIGWINCH, 1); | |
3028 | ||
3029 | put_pid(pgrp); | |
3030 | put_pid(rpgrp); | |
3031 | ||
1da177e4 LT |
3032 | tty->winsize = tmp_ws; |
3033 | real_tty->winsize = tmp_ws; | |
ca9bda00 | 3034 | done: |
5785c95b | 3035 | mutex_unlock(&tty->termios_mutex); |
1da177e4 LT |
3036 | return 0; |
3037 | } | |
3038 | ||
af9b897e AC |
3039 | /** |
3040 | * tioccons - allow admin to move logical console | |
3041 | * @file: the file to become console | |
3042 | * | |
3043 | * Allow the adminstrator to move the redirected console device | |
3044 | * | |
3045 | * Locking: uses redirect_lock to guard the redirect information | |
3046 | */ | |
3047 | ||
1da177e4 LT |
3048 | static int tioccons(struct file *file) |
3049 | { | |
3050 | if (!capable(CAP_SYS_ADMIN)) | |
3051 | return -EPERM; | |
3052 | if (file->f_op->write == redirected_tty_write) { | |
3053 | struct file *f; | |
3054 | spin_lock(&redirect_lock); | |
3055 | f = redirect; | |
3056 | redirect = NULL; | |
3057 | spin_unlock(&redirect_lock); | |
3058 | if (f) | |
3059 | fput(f); | |
3060 | return 0; | |
3061 | } | |
3062 | spin_lock(&redirect_lock); | |
3063 | if (redirect) { | |
3064 | spin_unlock(&redirect_lock); | |
3065 | return -EBUSY; | |
3066 | } | |
3067 | get_file(file); | |
3068 | redirect = file; | |
3069 | spin_unlock(&redirect_lock); | |
3070 | return 0; | |
3071 | } | |
3072 | ||
af9b897e AC |
3073 | /** |
3074 | * fionbio - non blocking ioctl | |
3075 | * @file: file to set blocking value | |
3076 | * @p: user parameter | |
3077 | * | |
3078 | * Historical tty interfaces had a blocking control ioctl before | |
3079 | * the generic functionality existed. This piece of history is preserved | |
3080 | * in the expected tty API of posix OS's. | |
3081 | * | |
3082 | * Locking: none, the open fle handle ensures it won't go away. | |
3083 | */ | |
1da177e4 LT |
3084 | |
3085 | static int fionbio(struct file *file, int __user *p) | |
3086 | { | |
3087 | int nonblock; | |
3088 | ||
3089 | if (get_user(nonblock, p)) | |
3090 | return -EFAULT; | |
3091 | ||
04f378b1 AC |
3092 | /* file->f_flags is still BKL protected in the fs layer - vomit */ |
3093 | lock_kernel(); | |
1da177e4 LT |
3094 | if (nonblock) |
3095 | file->f_flags |= O_NONBLOCK; | |
3096 | else | |
3097 | file->f_flags &= ~O_NONBLOCK; | |
04f378b1 | 3098 | unlock_kernel(); |
1da177e4 LT |
3099 | return 0; |
3100 | } | |
3101 | ||
af9b897e AC |
3102 | /** |
3103 | * tiocsctty - set controlling tty | |
3104 | * @tty: tty structure | |
3105 | * @arg: user argument | |
3106 | * | |
3107 | * This ioctl is used to manage job control. It permits a session | |
3108 | * leader to set this tty as the controlling tty for the session. | |
3109 | * | |
3110 | * Locking: | |
28298232 | 3111 | * Takes tty_mutex() to protect tty instance |
24ec839c PZ |
3112 | * Takes tasklist_lock internally to walk sessions |
3113 | * Takes ->siglock() when updating signal->tty | |
af9b897e AC |
3114 | */ |
3115 | ||
1da177e4 LT |
3116 | static int tiocsctty(struct tty_struct *tty, int arg) |
3117 | { | |
24ec839c | 3118 | int ret = 0; |
ab521dc0 | 3119 | if (current->signal->leader && (task_session(current) == tty->session)) |
24ec839c PZ |
3120 | return ret; |
3121 | ||
3122 | mutex_lock(&tty_mutex); | |
1da177e4 LT |
3123 | /* |
3124 | * The process must be a session leader and | |
3125 | * not have a controlling tty already. | |
3126 | */ | |
24ec839c PZ |
3127 | if (!current->signal->leader || current->signal->tty) { |
3128 | ret = -EPERM; | |
3129 | goto unlock; | |
3130 | } | |
3131 | ||
ab521dc0 | 3132 | if (tty->session) { |
1da177e4 LT |
3133 | /* |
3134 | * This tty is already the controlling | |
3135 | * tty for another session group! | |
3136 | */ | |
37bdfb07 | 3137 | if (arg == 1 && capable(CAP_SYS_ADMIN)) { |
1da177e4 LT |
3138 | /* |
3139 | * Steal it away | |
3140 | */ | |
1da177e4 | 3141 | read_lock(&tasklist_lock); |
24ec839c | 3142 | session_clear_tty(tty->session); |
1da177e4 | 3143 | read_unlock(&tasklist_lock); |
24ec839c PZ |
3144 | } else { |
3145 | ret = -EPERM; | |
3146 | goto unlock; | |
3147 | } | |
1da177e4 | 3148 | } |
24ec839c PZ |
3149 | proc_set_tty(current, tty); |
3150 | unlock: | |
28298232 | 3151 | mutex_unlock(&tty_mutex); |
24ec839c | 3152 | return ret; |
1da177e4 LT |
3153 | } |
3154 | ||
5d0fdf1e AC |
3155 | /** |
3156 | * tty_get_pgrp - return a ref counted pgrp pid | |
3157 | * @tty: tty to read | |
3158 | * | |
3159 | * Returns a refcounted instance of the pid struct for the process | |
3160 | * group controlling the tty. | |
3161 | */ | |
3162 | ||
3163 | struct pid *tty_get_pgrp(struct tty_struct *tty) | |
3164 | { | |
3165 | unsigned long flags; | |
3166 | struct pid *pgrp; | |
3167 | ||
3168 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
3169 | pgrp = get_pid(tty->pgrp); | |
3170 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); | |
3171 | ||
3172 | return pgrp; | |
3173 | } | |
3174 | EXPORT_SYMBOL_GPL(tty_get_pgrp); | |
3175 | ||
af9b897e AC |
3176 | /** |
3177 | * tiocgpgrp - get process group | |
3178 | * @tty: tty passed by user | |
3179 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3180 | * @p: returned pid | |
3181 | * | |
3182 | * Obtain the process group of the tty. If there is no process group | |
3183 | * return an error. | |
3184 | * | |
24ec839c | 3185 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3186 | */ |
3187 | ||
1da177e4 LT |
3188 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3189 | { | |
5d0fdf1e AC |
3190 | struct pid *pid; |
3191 | int ret; | |
1da177e4 LT |
3192 | /* |
3193 | * (tty == real_tty) is a cheap way of | |
3194 | * testing if the tty is NOT a master pty. | |
3195 | */ | |
3196 | if (tty == real_tty && current->signal->tty != real_tty) | |
3197 | return -ENOTTY; | |
5d0fdf1e AC |
3198 | pid = tty_get_pgrp(real_tty); |
3199 | ret = put_user(pid_vnr(pid), p); | |
3200 | put_pid(pid); | |
3201 | return ret; | |
1da177e4 LT |
3202 | } |
3203 | ||
af9b897e AC |
3204 | /** |
3205 | * tiocspgrp - attempt to set process group | |
3206 | * @tty: tty passed by user | |
3207 | * @real_tty: tty side device matching tty passed by user | |
3208 | * @p: pid pointer | |
3209 | * | |
3210 | * Set the process group of the tty to the session passed. Only | |
3211 | * permitted where the tty session is our session. | |
3212 | * | |
47f86834 | 3213 | * Locking: RCU, ctrl lock |
af9b897e AC |
3214 | */ |
3215 | ||
1da177e4 LT |
3216 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3217 | { | |
04a2e6a5 EB |
3218 | struct pid *pgrp; |
3219 | pid_t pgrp_nr; | |
1da177e4 | 3220 | int retval = tty_check_change(real_tty); |
47f86834 | 3221 | unsigned long flags; |
1da177e4 LT |
3222 | |
3223 | if (retval == -EIO) | |
3224 | return -ENOTTY; | |
3225 | if (retval) | |
3226 | return retval; | |
3227 | if (!current->signal->tty || | |
3228 | (current->signal->tty != real_tty) || | |
ab521dc0 | 3229 | (real_tty->session != task_session(current))) |
1da177e4 | 3230 | return -ENOTTY; |
04a2e6a5 | 3231 | if (get_user(pgrp_nr, p)) |
1da177e4 | 3232 | return -EFAULT; |
04a2e6a5 | 3233 | if (pgrp_nr < 0) |
1da177e4 | 3234 | return -EINVAL; |
04a2e6a5 | 3235 | rcu_read_lock(); |
b488893a | 3236 | pgrp = find_vpid(pgrp_nr); |
04a2e6a5 EB |
3237 | retval = -ESRCH; |
3238 | if (!pgrp) | |
3239 | goto out_unlock; | |
3240 | retval = -EPERM; | |
3241 | if (session_of_pgrp(pgrp) != task_session(current)) | |
3242 | goto out_unlock; | |
3243 | retval = 0; | |
47f86834 | 3244 | spin_lock_irqsave(&tty->ctrl_lock, flags); |
ab521dc0 EB |
3245 | put_pid(real_tty->pgrp); |
3246 | real_tty->pgrp = get_pid(pgrp); | |
47f86834 | 3247 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
04a2e6a5 EB |
3248 | out_unlock: |
3249 | rcu_read_unlock(); | |
3250 | return retval; | |
1da177e4 LT |
3251 | } |
3252 | ||
af9b897e AC |
3253 | /** |
3254 | * tiocgsid - get session id | |
3255 | * @tty: tty passed by user | |
3256 | * @real_tty: tty side of the tty pased by the user if a pty else the tty | |
3257 | * @p: pointer to returned session id | |
3258 | * | |
3259 | * Obtain the session id of the tty. If there is no session | |
3260 | * return an error. | |
3261 | * | |
24ec839c | 3262 | * Locking: none. Reference to current->signal->tty is safe. |
af9b897e AC |
3263 | */ |
3264 | ||
1da177e4 LT |
3265 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
3266 | { | |
3267 | /* | |
3268 | * (tty == real_tty) is a cheap way of | |
3269 | * testing if the tty is NOT a master pty. | |
3270 | */ | |
3271 | if (tty == real_tty && current->signal->tty != real_tty) | |
3272 | return -ENOTTY; | |
ab521dc0 | 3273 | if (!real_tty->session) |
1da177e4 | 3274 | return -ENOTTY; |
b488893a | 3275 | return put_user(pid_vnr(real_tty->session), p); |
1da177e4 LT |
3276 | } |
3277 | ||
af9b897e AC |
3278 | /** |
3279 | * tiocsetd - set line discipline | |
3280 | * @tty: tty device | |
3281 | * @p: pointer to user data | |
3282 | * | |
3283 | * Set the line discipline according to user request. | |
3284 | * | |
3285 | * Locking: see tty_set_ldisc, this function is just a helper | |
3286 | */ | |
3287 | ||
1da177e4 LT |
3288 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
3289 | { | |
3290 | int ldisc; | |
04f378b1 | 3291 | int ret; |
1da177e4 LT |
3292 | |
3293 | if (get_user(ldisc, p)) | |
3294 | return -EFAULT; | |
04f378b1 AC |
3295 | |
3296 | lock_kernel(); | |
3297 | ret = tty_set_ldisc(tty, ldisc); | |
3298 | unlock_kernel(); | |
3299 | ||
3300 | return ret; | |
1da177e4 LT |
3301 | } |
3302 | ||
af9b897e AC |
3303 | /** |
3304 | * send_break - performed time break | |
3305 | * @tty: device to break on | |
3306 | * @duration: timeout in mS | |
3307 | * | |
3308 | * Perform a timed break on hardware that lacks its own driver level | |
3309 | * timed break functionality. | |
3310 | * | |
3311 | * Locking: | |
28298232 | 3312 | * atomic_write_lock serializes |
af9b897e | 3313 | * |
af9b897e AC |
3314 | */ |
3315 | ||
b20f3ae5 | 3316 | static int send_break(struct tty_struct *tty, unsigned int duration) |
1da177e4 | 3317 | { |
9c1729db | 3318 | if (tty_write_lock(tty, 0) < 0) |
f34d7a5b AC |
3319 | return -EINTR; |
3320 | tty->ops->break_ctl(tty, -1); | |
9c1729db | 3321 | if (!signal_pending(current)) |
b20f3ae5 | 3322 | msleep_interruptible(duration); |
f34d7a5b | 3323 | tty->ops->break_ctl(tty, 0); |
9c1729db | 3324 | tty_write_unlock(tty); |
04f378b1 | 3325 | if (!signal_pending(current)) |
f34d7a5b AC |
3326 | return -EINTR; |
3327 | return 0; | |
1da177e4 LT |
3328 | } |
3329 | ||
af9b897e | 3330 | /** |
f34d7a5b | 3331 | * tty_tiocmget - get modem status |
af9b897e AC |
3332 | * @tty: tty device |
3333 | * @file: user file pointer | |
3334 | * @p: pointer to result | |
3335 | * | |
3336 | * Obtain the modem status bits from the tty driver if the feature | |
3337 | * is supported. Return -EINVAL if it is not available. | |
3338 | * | |
3339 | * Locking: none (up to the driver) | |
3340 | */ | |
3341 | ||
3342 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) | |
1da177e4 LT |
3343 | { |
3344 | int retval = -EINVAL; | |
3345 | ||
f34d7a5b AC |
3346 | if (tty->ops->tiocmget) { |
3347 | retval = tty->ops->tiocmget(tty, file); | |
1da177e4 LT |
3348 | |
3349 | if (retval >= 0) | |
3350 | retval = put_user(retval, p); | |
3351 | } | |
3352 | return retval; | |
3353 | } | |
3354 | ||
af9b897e | 3355 | /** |
f34d7a5b | 3356 | * tty_tiocmset - set modem status |
af9b897e AC |
3357 | * @tty: tty device |
3358 | * @file: user file pointer | |
3359 | * @cmd: command - clear bits, set bits or set all | |
3360 | * @p: pointer to desired bits | |
3361 | * | |
3362 | * Set the modem status bits from the tty driver if the feature | |
3363 | * is supported. Return -EINVAL if it is not available. | |
3364 | * | |
3365 | * Locking: none (up to the driver) | |
3366 | */ | |
3367 | ||
3368 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, | |
1da177e4 LT |
3369 | unsigned __user *p) |
3370 | { | |
3371 | int retval = -EINVAL; | |
3372 | ||
f34d7a5b | 3373 | if (tty->ops->tiocmset) { |
1da177e4 LT |
3374 | unsigned int set, clear, val; |
3375 | ||
3376 | retval = get_user(val, p); | |
3377 | if (retval) | |
3378 | return retval; | |
3379 | ||
3380 | set = clear = 0; | |
3381 | switch (cmd) { | |
3382 | case TIOCMBIS: | |
3383 | set = val; | |
3384 | break; | |
3385 | case TIOCMBIC: | |
3386 | clear = val; | |
3387 | break; | |
3388 | case TIOCMSET: | |
3389 | set = val; | |
3390 | clear = ~val; | |
3391 | break; | |
3392 | } | |
3393 | ||
3394 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3395 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; | |
3396 | ||
f34d7a5b | 3397 | retval = tty->ops->tiocmset(tty, file, set, clear); |
1da177e4 LT |
3398 | } |
3399 | return retval; | |
3400 | } | |
3401 | ||
3402 | /* | |
3403 | * Split this up, as gcc can choke on it otherwise.. | |
3404 | */ | |
04f378b1 | 3405 | long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
1da177e4 LT |
3406 | { |
3407 | struct tty_struct *tty, *real_tty; | |
3408 | void __user *p = (void __user *)arg; | |
3409 | int retval; | |
3410 | struct tty_ldisc *ld; | |
04f378b1 | 3411 | struct inode *inode = file->f_dentry->d_inode; |
37bdfb07 | 3412 | |
1da177e4 LT |
3413 | tty = (struct tty_struct *)file->private_data; |
3414 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3415 | return -EINVAL; | |
3416 | ||
3417 | real_tty = tty; | |
3418 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && | |
3419 | tty->driver->subtype == PTY_TYPE_MASTER) | |
3420 | real_tty = tty->link; | |
3421 | ||
3422 | /* | |
3423 | * Break handling by driver | |
3424 | */ | |
04f378b1 AC |
3425 | |
3426 | retval = -EINVAL; | |
3427 | ||
f34d7a5b | 3428 | if (!tty->ops->break_ctl) { |
37bdfb07 | 3429 | switch (cmd) { |
1da177e4 LT |
3430 | case TIOCSBRK: |
3431 | case TIOCCBRK: | |
f34d7a5b AC |
3432 | if (tty->ops->ioctl) |
3433 | retval = tty->ops->ioctl(tty, file, cmd, arg); | |
3434 | if (retval != -EINVAL && retval != -ENOIOCTLCMD) | |
3435 | printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name); | |
04f378b1 | 3436 | return retval; |
37bdfb07 | 3437 | |
1da177e4 LT |
3438 | /* These two ioctl's always return success; even if */ |
3439 | /* the driver doesn't support them. */ | |
3440 | case TCSBRK: | |
3441 | case TCSBRKP: | |
f34d7a5b | 3442 | if (!tty->ops->ioctl) |
1da177e4 | 3443 | return 0; |
f34d7a5b AC |
3444 | retval = tty->ops->ioctl(tty, file, cmd, arg); |
3445 | if (retval != -EINVAL && retval != -ENOIOCTLCMD) | |
3446 | printk(KERN_WARNING "tty: driver %s needs updating to use break_ctl\n", tty->driver->name); | |
1da177e4 LT |
3447 | if (retval == -ENOIOCTLCMD) |
3448 | retval = 0; | |
3449 | return retval; | |
3450 | } | |
3451 | } | |
3452 | ||
3453 | /* | |
3454 | * Factor out some common prep work | |
3455 | */ | |
3456 | switch (cmd) { | |
3457 | case TIOCSETD: | |
3458 | case TIOCSBRK: | |
3459 | case TIOCCBRK: | |
3460 | case TCSBRK: | |
37bdfb07 | 3461 | case TCSBRKP: |
1da177e4 LT |
3462 | retval = tty_check_change(tty); |
3463 | if (retval) | |
3464 | return retval; | |
3465 | if (cmd != TIOCCBRK) { | |
3466 | tty_wait_until_sent(tty, 0); | |
3467 | if (signal_pending(current)) | |
3468 | return -EINTR; | |
3469 | } | |
3470 | break; | |
3471 | } | |
3472 | ||
3473 | switch (cmd) { | |
37bdfb07 AC |
3474 | case TIOCSTI: |
3475 | return tiocsti(tty, p); | |
3476 | case TIOCGWINSZ: | |
3477 | return tiocgwinsz(tty, p); | |
3478 | case TIOCSWINSZ: | |
3479 | return tiocswinsz(tty, real_tty, p); | |
3480 | case TIOCCONS: | |
3481 | return real_tty != tty ? -EINVAL : tioccons(file); | |
3482 | case FIONBIO: | |
3483 | return fionbio(file, p); | |
3484 | case TIOCEXCL: | |
3485 | set_bit(TTY_EXCLUSIVE, &tty->flags); | |
3486 | return 0; | |
3487 | case TIOCNXCL: | |
3488 | clear_bit(TTY_EXCLUSIVE, &tty->flags); | |
3489 | return 0; | |
3490 | case TIOCNOTTY: | |
3491 | if (current->signal->tty != tty) | |
3492 | return -ENOTTY; | |
3493 | no_tty(); | |
3494 | return 0; | |
3495 | case TIOCSCTTY: | |
3496 | return tiocsctty(tty, arg); | |
3497 | case TIOCGPGRP: | |
3498 | return tiocgpgrp(tty, real_tty, p); | |
3499 | case TIOCSPGRP: | |
3500 | return tiocspgrp(tty, real_tty, p); | |
3501 | case TIOCGSID: | |
3502 | return tiocgsid(tty, real_tty, p); | |
3503 | case TIOCGETD: | |
37bdfb07 AC |
3504 | return put_user(tty->ldisc.num, (int __user *)p); |
3505 | case TIOCSETD: | |
3506 | return tiocsetd(tty, p); | |
1da177e4 | 3507 | #ifdef CONFIG_VT |
37bdfb07 AC |
3508 | case TIOCLINUX: |
3509 | return tioclinux(tty, arg); | |
1da177e4 | 3510 | #endif |
37bdfb07 AC |
3511 | /* |
3512 | * Break handling | |
3513 | */ | |
3514 | case TIOCSBRK: /* Turn break on, unconditionally */ | |
f34d7a5b AC |
3515 | if (tty->ops->break_ctl) |
3516 | tty->ops->break_ctl(tty, -1); | |
37bdfb07 | 3517 | return 0; |
1da177e4 | 3518 | |
37bdfb07 | 3519 | case TIOCCBRK: /* Turn break off, unconditionally */ |
f34d7a5b AC |
3520 | if (tty->ops->break_ctl) |
3521 | tty->ops->break_ctl(tty, 0); | |
37bdfb07 AC |
3522 | return 0; |
3523 | case TCSBRK: /* SVID version: non-zero arg --> no break */ | |
3524 | /* non-zero arg means wait for all output data | |
3525 | * to be sent (performed above) but don't send break. | |
3526 | * This is used by the tcdrain() termios function. | |
3527 | */ | |
3528 | if (!arg) | |
3529 | return send_break(tty, 250); | |
3530 | return 0; | |
3531 | case TCSBRKP: /* support for POSIX tcsendbreak() */ | |
3532 | return send_break(tty, arg ? arg*100 : 250); | |
3533 | ||
3534 | case TIOCMGET: | |
3535 | return tty_tiocmget(tty, file, p); | |
3536 | case TIOCMSET: | |
3537 | case TIOCMBIC: | |
3538 | case TIOCMBIS: | |
3539 | return tty_tiocmset(tty, file, cmd, p); | |
3540 | case TCFLSH: | |
3541 | switch (arg) { | |
3542 | case TCIFLUSH: | |
3543 | case TCIOFLUSH: | |
3544 | /* flush tty buffer and allow ldisc to process ioctl */ | |
3545 | tty_buffer_flush(tty); | |
c5c34d48 | 3546 | break; |
37bdfb07 AC |
3547 | } |
3548 | break; | |
1da177e4 | 3549 | } |
f34d7a5b AC |
3550 | if (tty->ops->ioctl) { |
3551 | retval = (tty->ops->ioctl)(tty, file, cmd, arg); | |
1da177e4 LT |
3552 | if (retval != -ENOIOCTLCMD) |
3553 | return retval; | |
3554 | } | |
3555 | ld = tty_ldisc_ref_wait(tty); | |
3556 | retval = -EINVAL; | |
3557 | if (ld->ioctl) { | |
3558 | retval = ld->ioctl(tty, file, cmd, arg); | |
3559 | if (retval == -ENOIOCTLCMD) | |
3560 | retval = -EINVAL; | |
3561 | } | |
3562 | tty_ldisc_deref(ld); | |
3563 | return retval; | |
3564 | } | |
3565 | ||
e10cc1df | 3566 | #ifdef CONFIG_COMPAT |
37bdfb07 | 3567 | static long tty_compat_ioctl(struct file *file, unsigned int cmd, |
e10cc1df PF |
3568 | unsigned long arg) |
3569 | { | |
3570 | struct inode *inode = file->f_dentry->d_inode; | |
3571 | struct tty_struct *tty = file->private_data; | |
3572 | struct tty_ldisc *ld; | |
3573 | int retval = -ENOIOCTLCMD; | |
3574 | ||
3575 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) | |
3576 | return -EINVAL; | |
3577 | ||
f34d7a5b AC |
3578 | if (tty->ops->compat_ioctl) { |
3579 | retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg); | |
e10cc1df PF |
3580 | if (retval != -ENOIOCTLCMD) |
3581 | return retval; | |
3582 | } | |
3583 | ||
3584 | ld = tty_ldisc_ref_wait(tty); | |
3585 | if (ld->compat_ioctl) | |
3586 | retval = ld->compat_ioctl(tty, file, cmd, arg); | |
3587 | tty_ldisc_deref(ld); | |
3588 | ||
3589 | return retval; | |
3590 | } | |
3591 | #endif | |
1da177e4 LT |
3592 | |
3593 | /* | |
3594 | * This implements the "Secure Attention Key" --- the idea is to | |
3595 | * prevent trojan horses by killing all processes associated with this | |
3596 | * tty when the user hits the "Secure Attention Key". Required for | |
3597 | * super-paranoid applications --- see the Orange Book for more details. | |
37bdfb07 | 3598 | * |
1da177e4 LT |
3599 | * This code could be nicer; ideally it should send a HUP, wait a few |
3600 | * seconds, then send a INT, and then a KILL signal. But you then | |
3601 | * have to coordinate with the init process, since all processes associated | |
3602 | * with the current tty must be dead before the new getty is allowed | |
3603 | * to spawn. | |
3604 | * | |
3605 | * Now, if it would be correct ;-/ The current code has a nasty hole - | |
3606 | * it doesn't catch files in flight. We may send the descriptor to ourselves | |
3607 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. | |
3608 | * | |
3609 | * Nasty bug: do_SAK is being called in interrupt context. This can | |
3610 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 | |
3611 | */ | |
8b6312f4 | 3612 | void __do_SAK(struct tty_struct *tty) |
1da177e4 LT |
3613 | { |
3614 | #ifdef TTY_SOFT_SAK | |
3615 | tty_hangup(tty); | |
3616 | #else | |
652486fb | 3617 | struct task_struct *g, *p; |
ab521dc0 | 3618 | struct pid *session; |
1da177e4 LT |
3619 | int i; |
3620 | struct file *filp; | |
badf1662 | 3621 | struct fdtable *fdt; |
37bdfb07 | 3622 | |
1da177e4 LT |
3623 | if (!tty) |
3624 | return; | |
24ec839c | 3625 | session = tty->session; |
37bdfb07 | 3626 | |
b3f13deb | 3627 | tty_ldisc_flush(tty); |
1da177e4 | 3628 | |
f34d7a5b | 3629 | tty_driver_flush_buffer(tty); |
37bdfb07 | 3630 | |
1da177e4 | 3631 | read_lock(&tasklist_lock); |
652486fb | 3632 | /* Kill the entire session */ |
ab521dc0 | 3633 | do_each_pid_task(session, PIDTYPE_SID, p) { |
652486fb | 3634 | printk(KERN_NOTICE "SAK: killed process %d" |
a47afb0f | 3635 | " (%s): task_session_nr(p)==tty->session\n", |
ba25f9dc | 3636 | task_pid_nr(p), p->comm); |
652486fb | 3637 | send_sig(SIGKILL, p, 1); |
ab521dc0 | 3638 | } while_each_pid_task(session, PIDTYPE_SID, p); |
652486fb EB |
3639 | /* Now kill any processes that happen to have the |
3640 | * tty open. | |
3641 | */ | |
3642 | do_each_thread(g, p) { | |
3643 | if (p->signal->tty == tty) { | |
1da177e4 | 3644 | printk(KERN_NOTICE "SAK: killed process %d" |
a47afb0f | 3645 | " (%s): task_session_nr(p)==tty->session\n", |
ba25f9dc | 3646 | task_pid_nr(p), p->comm); |
1da177e4 LT |
3647 | send_sig(SIGKILL, p, 1); |
3648 | continue; | |
3649 | } | |
3650 | task_lock(p); | |
3651 | if (p->files) { | |
ca99c1da DS |
3652 | /* |
3653 | * We don't take a ref to the file, so we must | |
3654 | * hold ->file_lock instead. | |
3655 | */ | |
3656 | spin_lock(&p->files->file_lock); | |
badf1662 | 3657 | fdt = files_fdtable(p->files); |
37bdfb07 | 3658 | for (i = 0; i < fdt->max_fds; i++) { |
1da177e4 LT |
3659 | filp = fcheck_files(p->files, i); |
3660 | if (!filp) | |
3661 | continue; | |
3662 | if (filp->f_op->read == tty_read && | |
3663 | filp->private_data == tty) { | |
3664 | printk(KERN_NOTICE "SAK: killed process %d" | |
3665 | " (%s): fd#%d opened to the tty\n", | |
ba25f9dc | 3666 | task_pid_nr(p), p->comm, i); |
20ac9437 | 3667 | force_sig(SIGKILL, p); |
1da177e4 LT |
3668 | break; |
3669 | } | |
3670 | } | |
ca99c1da | 3671 | spin_unlock(&p->files->file_lock); |
1da177e4 LT |
3672 | } |
3673 | task_unlock(p); | |
652486fb | 3674 | } while_each_thread(g, p); |
1da177e4 LT |
3675 | read_unlock(&tasklist_lock); |
3676 | #endif | |
3677 | } | |
3678 | ||
8b6312f4 EB |
3679 | static void do_SAK_work(struct work_struct *work) |
3680 | { | |
3681 | struct tty_struct *tty = | |
3682 | container_of(work, struct tty_struct, SAK_work); | |
3683 | __do_SAK(tty); | |
3684 | } | |
3685 | ||
1da177e4 LT |
3686 | /* |
3687 | * The tq handling here is a little racy - tty->SAK_work may already be queued. | |
3688 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, | |
3689 | * the values which we write to it will be identical to the values which it | |
3690 | * already has. --akpm | |
3691 | */ | |
3692 | void do_SAK(struct tty_struct *tty) | |
3693 | { | |
3694 | if (!tty) | |
3695 | return; | |
1da177e4 LT |
3696 | schedule_work(&tty->SAK_work); |
3697 | } | |
3698 | ||
3699 | EXPORT_SYMBOL(do_SAK); | |
3700 | ||
af9b897e AC |
3701 | /** |
3702 | * flush_to_ldisc | |
65f27f38 | 3703 | * @work: tty structure passed from work queue. |
af9b897e AC |
3704 | * |
3705 | * This routine is called out of the software interrupt to flush data | |
3706 | * from the buffer chain to the line discipline. | |
3707 | * | |
3708 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock | |
3709 | * while invoking the line discipline receive_buf method. The | |
3710 | * receive_buf method is single threaded for each tty instance. | |
1da177e4 | 3711 | */ |
37bdfb07 | 3712 | |
65f27f38 | 3713 | static void flush_to_ldisc(struct work_struct *work) |
1da177e4 | 3714 | { |
65f27f38 DH |
3715 | struct tty_struct *tty = |
3716 | container_of(work, struct tty_struct, buf.work.work); | |
1da177e4 LT |
3717 | unsigned long flags; |
3718 | struct tty_ldisc *disc; | |
2c3bb20f | 3719 | struct tty_buffer *tbuf, *head; |
8977d929 PF |
3720 | char *char_buf; |
3721 | unsigned char *flag_buf; | |
1da177e4 LT |
3722 | |
3723 | disc = tty_ldisc_ref(tty); | |
3724 | if (disc == NULL) /* !TTY_LDISC */ | |
3725 | return; | |
3726 | ||
808249ce | 3727 | spin_lock_irqsave(&tty->buf.lock, flags); |
37bdfb07 AC |
3728 | /* So we know a flush is running */ |
3729 | set_bit(TTY_FLUSHING, &tty->flags); | |
2c3bb20f PF |
3730 | head = tty->buf.head; |
3731 | if (head != NULL) { | |
3732 | tty->buf.head = NULL; | |
3733 | for (;;) { | |
3734 | int count = head->commit - head->read; | |
3735 | if (!count) { | |
3736 | if (head->next == NULL) | |
3737 | break; | |
3738 | tbuf = head; | |
3739 | head = head->next; | |
3740 | tty_buffer_free(tty, tbuf); | |
3741 | continue; | |
3742 | } | |
42fd552e AC |
3743 | /* Ldisc or user is trying to flush the buffers |
3744 | we are feeding to the ldisc, stop feeding the | |
3745 | line discipline as we want to empty the queue */ | |
3746 | if (test_bit(TTY_FLUSHPENDING, &tty->flags)) | |
3747 | break; | |
2c3bb20f PF |
3748 | if (!tty->receive_room) { |
3749 | schedule_delayed_work(&tty->buf.work, 1); | |
3750 | break; | |
3751 | } | |
3752 | if (count > tty->receive_room) | |
3753 | count = tty->receive_room; | |
3754 | char_buf = head->char_buf_ptr + head->read; | |
3755 | flag_buf = head->flag_buf_ptr + head->read; | |
3756 | head->read += count; | |
8977d929 PF |
3757 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3758 | disc->receive_buf(tty, char_buf, flag_buf, count); | |
3759 | spin_lock_irqsave(&tty->buf.lock, flags); | |
3760 | } | |
42fd552e | 3761 | /* Restore the queue head */ |
2c3bb20f | 3762 | tty->buf.head = head; |
33f0f88f | 3763 | } |
42fd552e AC |
3764 | /* We may have a deferred request to flush the input buffer, |
3765 | if so pull the chain under the lock and empty the queue */ | |
3766 | if (test_bit(TTY_FLUSHPENDING, &tty->flags)) { | |
3767 | __tty_buffer_flush(tty); | |
3768 | clear_bit(TTY_FLUSHPENDING, &tty->flags); | |
3769 | wake_up(&tty->read_wait); | |
3770 | } | |
3771 | clear_bit(TTY_FLUSHING, &tty->flags); | |
808249ce | 3772 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
817d6d3b | 3773 | |
1da177e4 LT |
3774 | tty_ldisc_deref(disc); |
3775 | } | |
3776 | ||
1da177e4 LT |
3777 | /** |
3778 | * tty_flip_buffer_push - terminal | |
3779 | * @tty: tty to push | |
3780 | * | |
3781 | * Queue a push of the terminal flip buffers to the line discipline. This | |
3782 | * function must not be called from IRQ context if tty->low_latency is set. | |
3783 | * | |
3784 | * In the event of the queue being busy for flipping the work will be | |
3785 | * held off and retried later. | |
af9b897e AC |
3786 | * |
3787 | * Locking: tty buffer lock. Driver locks in low latency mode. | |
1da177e4 LT |
3788 | */ |
3789 | ||
3790 | void tty_flip_buffer_push(struct tty_struct *tty) | |
3791 | { | |
808249ce PF |
3792 | unsigned long flags; |
3793 | spin_lock_irqsave(&tty->buf.lock, flags); | |
33b37a33 | 3794 | if (tty->buf.tail != NULL) |
8977d929 | 3795 | tty->buf.tail->commit = tty->buf.tail->used; |
808249ce PF |
3796 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
3797 | ||
1da177e4 | 3798 | if (tty->low_latency) |
65f27f38 | 3799 | flush_to_ldisc(&tty->buf.work.work); |
1da177e4 | 3800 | else |
33f0f88f | 3801 | schedule_delayed_work(&tty->buf.work, 1); |
1da177e4 LT |
3802 | } |
3803 | ||
3804 | EXPORT_SYMBOL(tty_flip_buffer_push); | |
3805 | ||
33f0f88f | 3806 | |
af9b897e AC |
3807 | /** |
3808 | * initialize_tty_struct | |
3809 | * @tty: tty to initialize | |
3810 | * | |
3811 | * This subroutine initializes a tty structure that has been newly | |
3812 | * allocated. | |
3813 | * | |
3814 | * Locking: none - tty in question must not be exposed at this point | |
1da177e4 | 3815 | */ |
af9b897e | 3816 | |
1da177e4 LT |
3817 | static void initialize_tty_struct(struct tty_struct *tty) |
3818 | { | |
3819 | memset(tty, 0, sizeof(struct tty_struct)); | |
3820 | tty->magic = TTY_MAGIC; | |
3821 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); | |
ab521dc0 EB |
3822 | tty->session = NULL; |
3823 | tty->pgrp = NULL; | |
1da177e4 | 3824 | tty->overrun_time = jiffies; |
33f0f88f AC |
3825 | tty->buf.head = tty->buf.tail = NULL; |
3826 | tty_buffer_init(tty); | |
65f27f38 | 3827 | INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc); |
5785c95b | 3828 | mutex_init(&tty->termios_mutex); |
1da177e4 LT |
3829 | init_waitqueue_head(&tty->write_wait); |
3830 | init_waitqueue_head(&tty->read_wait); | |
65f27f38 | 3831 | INIT_WORK(&tty->hangup_work, do_tty_hangup); |
70522e12 IM |
3832 | mutex_init(&tty->atomic_read_lock); |
3833 | mutex_init(&tty->atomic_write_lock); | |
1da177e4 | 3834 | spin_lock_init(&tty->read_lock); |
04f378b1 | 3835 | spin_lock_init(&tty->ctrl_lock); |
1da177e4 | 3836 | INIT_LIST_HEAD(&tty->tty_files); |
7f1f86a0 | 3837 | INIT_WORK(&tty->SAK_work, do_SAK_work); |
1da177e4 LT |
3838 | } |
3839 | ||
f34d7a5b AC |
3840 | /** |
3841 | * tty_put_char - write one character to a tty | |
3842 | * @tty: tty | |
3843 | * @ch: character | |
3844 | * | |
3845 | * Write one byte to the tty using the provided put_char method | |
3846 | * if present. Returns the number of characters successfully output. | |
3847 | * | |
3848 | * Note: the specific put_char operation in the driver layer may go | |
3849 | * away soon. Don't call it directly, use this method | |
1da177e4 | 3850 | */ |
af9b897e | 3851 | |
f34d7a5b | 3852 | int tty_put_char(struct tty_struct *tty, unsigned char ch) |
1da177e4 | 3853 | { |
f34d7a5b AC |
3854 | if (tty->ops->put_char) |
3855 | return tty->ops->put_char(tty, ch); | |
3856 | return tty->ops->write(tty, &ch, 1); | |
1da177e4 LT |
3857 | } |
3858 | ||
f34d7a5b AC |
3859 | EXPORT_SYMBOL_GPL(tty_put_char); |
3860 | ||
7fe845d1 | 3861 | static struct class *tty_class; |
1da177e4 LT |
3862 | |
3863 | /** | |
af9b897e AC |
3864 | * tty_register_device - register a tty device |
3865 | * @driver: the tty driver that describes the tty device | |
3866 | * @index: the index in the tty driver for this tty device | |
3867 | * @device: a struct device that is associated with this tty device. | |
3868 | * This field is optional, if there is no known struct device | |
3869 | * for this tty device it can be set to NULL safely. | |
1da177e4 | 3870 | * |
01107d34 GKH |
3871 | * Returns a pointer to the struct device for this tty device |
3872 | * (or ERR_PTR(-EFOO) on error). | |
1cdcb6b4 | 3873 | * |
af9b897e AC |
3874 | * This call is required to be made to register an individual tty device |
3875 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If | |
3876 | * that bit is not set, this function should not be called by a tty | |
3877 | * driver. | |
3878 | * | |
3879 | * Locking: ?? | |
1da177e4 | 3880 | */ |
af9b897e | 3881 | |
01107d34 GKH |
3882 | struct device *tty_register_device(struct tty_driver *driver, unsigned index, |
3883 | struct device *device) | |
1da177e4 LT |
3884 | { |
3885 | char name[64]; | |
3886 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; | |
3887 | ||
3888 | if (index >= driver->num) { | |
3889 | printk(KERN_ERR "Attempt to register invalid tty line number " | |
3890 | " (%d).\n", index); | |
1cdcb6b4 | 3891 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
3892 | } |
3893 | ||
1da177e4 LT |
3894 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
3895 | pty_line_name(driver, index, name); | |
3896 | else | |
3897 | tty_line_name(driver, index, name); | |
1cdcb6b4 | 3898 | |
01107d34 | 3899 | return device_create(tty_class, device, dev, name); |
1da177e4 LT |
3900 | } |
3901 | ||
3902 | /** | |
af9b897e AC |
3903 | * tty_unregister_device - unregister a tty device |
3904 | * @driver: the tty driver that describes the tty device | |
3905 | * @index: the index in the tty driver for this tty device | |
1da177e4 | 3906 | * |
af9b897e AC |
3907 | * If a tty device is registered with a call to tty_register_device() then |
3908 | * this function must be called when the tty device is gone. | |
3909 | * | |
3910 | * Locking: ?? | |
1da177e4 | 3911 | */ |
af9b897e | 3912 | |
1da177e4 LT |
3913 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
3914 | { | |
37bdfb07 AC |
3915 | device_destroy(tty_class, |
3916 | MKDEV(driver->major, driver->minor_start) + index); | |
1da177e4 LT |
3917 | } |
3918 | ||
3919 | EXPORT_SYMBOL(tty_register_device); | |
3920 | EXPORT_SYMBOL(tty_unregister_device); | |
3921 | ||
3922 | struct tty_driver *alloc_tty_driver(int lines) | |
3923 | { | |
3924 | struct tty_driver *driver; | |
3925 | ||
506eb99a | 3926 | driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL); |
1da177e4 | 3927 | if (driver) { |
1da177e4 LT |
3928 | driver->magic = TTY_DRIVER_MAGIC; |
3929 | driver->num = lines; | |
3930 | /* later we'll move allocation of tables here */ | |
3931 | } | |
3932 | return driver; | |
3933 | } | |
3934 | ||
3935 | void put_tty_driver(struct tty_driver *driver) | |
3936 | { | |
3937 | kfree(driver); | |
3938 | } | |
3939 | ||
b68e31d0 JD |
3940 | void tty_set_operations(struct tty_driver *driver, |
3941 | const struct tty_operations *op) | |
1da177e4 | 3942 | { |
f34d7a5b AC |
3943 | driver->ops = op; |
3944 | }; | |
1da177e4 LT |
3945 | |
3946 | EXPORT_SYMBOL(alloc_tty_driver); | |
3947 | EXPORT_SYMBOL(put_tty_driver); | |
3948 | EXPORT_SYMBOL(tty_set_operations); | |
3949 | ||
3950 | /* | |
3951 | * Called by a tty driver to register itself. | |
3952 | */ | |
3953 | int tty_register_driver(struct tty_driver *driver) | |
3954 | { | |
3955 | int error; | |
37bdfb07 | 3956 | int i; |
1da177e4 LT |
3957 | dev_t dev; |
3958 | void **p = NULL; | |
3959 | ||
3960 | if (driver->flags & TTY_DRIVER_INSTALLED) | |
3961 | return 0; | |
3962 | ||
543691a6 AW |
3963 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) { |
3964 | p = kzalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); | |
1da177e4 LT |
3965 | if (!p) |
3966 | return -ENOMEM; | |
1da177e4 LT |
3967 | } |
3968 | ||
3969 | if (!driver->major) { | |
37bdfb07 AC |
3970 | error = alloc_chrdev_region(&dev, driver->minor_start, |
3971 | driver->num, driver->name); | |
1da177e4 LT |
3972 | if (!error) { |
3973 | driver->major = MAJOR(dev); | |
3974 | driver->minor_start = MINOR(dev); | |
3975 | } | |
3976 | } else { | |
3977 | dev = MKDEV(driver->major, driver->minor_start); | |
e5717c48 | 3978 | error = register_chrdev_region(dev, driver->num, driver->name); |
1da177e4 LT |
3979 | } |
3980 | if (error < 0) { | |
3981 | kfree(p); | |
3982 | return error; | |
3983 | } | |
3984 | ||
3985 | if (p) { | |
3986 | driver->ttys = (struct tty_struct **)p; | |
edc6afc5 | 3987 | driver->termios = (struct ktermios **)(p + driver->num); |
37bdfb07 AC |
3988 | driver->termios_locked = (struct ktermios **) |
3989 | (p + driver->num * 2); | |
1da177e4 LT |
3990 | } else { |
3991 | driver->ttys = NULL; | |
3992 | driver->termios = NULL; | |
3993 | driver->termios_locked = NULL; | |
3994 | } | |
3995 | ||
3996 | cdev_init(&driver->cdev, &tty_fops); | |
3997 | driver->cdev.owner = driver->owner; | |
3998 | error = cdev_add(&driver->cdev, dev, driver->num); | |
3999 | if (error) { | |
1da177e4 LT |
4000 | unregister_chrdev_region(dev, driver->num); |
4001 | driver->ttys = NULL; | |
4002 | driver->termios = driver->termios_locked = NULL; | |
4003 | kfree(p); | |
4004 | return error; | |
4005 | } | |
4006 | ||
ca509f69 | 4007 | mutex_lock(&tty_mutex); |
1da177e4 | 4008 | list_add(&driver->tty_drivers, &tty_drivers); |
ca509f69 | 4009 | mutex_unlock(&tty_mutex); |
37bdfb07 AC |
4010 | |
4011 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) { | |
4012 | for (i = 0; i < driver->num; i++) | |
1da177e4 LT |
4013 | tty_register_device(driver, i, NULL); |
4014 | } | |
4015 | proc_tty_register_driver(driver); | |
4016 | return 0; | |
4017 | } | |
4018 | ||
4019 | EXPORT_SYMBOL(tty_register_driver); | |
4020 | ||
4021 | /* | |
4022 | * Called by a tty driver to unregister itself. | |
4023 | */ | |
4024 | int tty_unregister_driver(struct tty_driver *driver) | |
4025 | { | |
4026 | int i; | |
edc6afc5 | 4027 | struct ktermios *tp; |
1da177e4 LT |
4028 | void *p; |
4029 | ||
4030 | if (driver->refcount) | |
4031 | return -EBUSY; | |
4032 | ||
4033 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), | |
4034 | driver->num); | |
ca509f69 | 4035 | mutex_lock(&tty_mutex); |
1da177e4 | 4036 | list_del(&driver->tty_drivers); |
ca509f69 | 4037 | mutex_unlock(&tty_mutex); |
1da177e4 LT |
4038 | |
4039 | /* | |
4040 | * Free the termios and termios_locked structures because | |
4041 | * we don't want to get memory leaks when modular tty | |
4042 | * drivers are removed from the kernel. | |
4043 | */ | |
4044 | for (i = 0; i < driver->num; i++) { | |
4045 | tp = driver->termios[i]; | |
4046 | if (tp) { | |
4047 | driver->termios[i] = NULL; | |
4048 | kfree(tp); | |
4049 | } | |
4050 | tp = driver->termios_locked[i]; | |
4051 | if (tp) { | |
4052 | driver->termios_locked[i] = NULL; | |
4053 | kfree(tp); | |
4054 | } | |
331b8319 | 4055 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
1da177e4 LT |
4056 | tty_unregister_device(driver, i); |
4057 | } | |
4058 | p = driver->ttys; | |
4059 | proc_tty_unregister_driver(driver); | |
4060 | driver->ttys = NULL; | |
4061 | driver->termios = driver->termios_locked = NULL; | |
4062 | kfree(p); | |
4063 | cdev_del(&driver->cdev); | |
4064 | return 0; | |
4065 | } | |
1da177e4 LT |
4066 | EXPORT_SYMBOL(tty_unregister_driver); |
4067 | ||
24ec839c PZ |
4068 | dev_t tty_devnum(struct tty_struct *tty) |
4069 | { | |
4070 | return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index; | |
4071 | } | |
4072 | EXPORT_SYMBOL(tty_devnum); | |
4073 | ||
4074 | void proc_clear_tty(struct task_struct *p) | |
4075 | { | |
4076 | spin_lock_irq(&p->sighand->siglock); | |
4077 | p->signal->tty = NULL; | |
4078 | spin_unlock_irq(&p->sighand->siglock); | |
4079 | } | |
7cac4ce5 | 4080 | EXPORT_SYMBOL(proc_clear_tty); |
24ec839c | 4081 | |
47f86834 AC |
4082 | /* Called under the sighand lock */ |
4083 | ||
2a65f1d9 | 4084 | static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
4085 | { |
4086 | if (tty) { | |
47f86834 AC |
4087 | unsigned long flags; |
4088 | /* We should not have a session or pgrp to put here but.... */ | |
4089 | spin_lock_irqsave(&tty->ctrl_lock, flags); | |
d9c1e9a8 EB |
4090 | put_pid(tty->session); |
4091 | put_pid(tty->pgrp); | |
ab521dc0 | 4092 | tty->pgrp = get_pid(task_pgrp(tsk)); |
47f86834 AC |
4093 | spin_unlock_irqrestore(&tty->ctrl_lock, flags); |
4094 | tty->session = get_pid(task_session(tsk)); | |
24ec839c | 4095 | } |
2a65f1d9 | 4096 | put_pid(tsk->signal->tty_old_pgrp); |
24ec839c | 4097 | tsk->signal->tty = tty; |
ab521dc0 | 4098 | tsk->signal->tty_old_pgrp = NULL; |
24ec839c PZ |
4099 | } |
4100 | ||
98a27ba4 | 4101 | static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty) |
24ec839c PZ |
4102 | { |
4103 | spin_lock_irq(&tsk->sighand->siglock); | |
2a65f1d9 | 4104 | __proc_set_tty(tsk, tty); |
24ec839c PZ |
4105 | spin_unlock_irq(&tsk->sighand->siglock); |
4106 | } | |
4107 | ||
4108 | struct tty_struct *get_current_tty(void) | |
4109 | { | |
4110 | struct tty_struct *tty; | |
4111 | WARN_ON_ONCE(!mutex_is_locked(&tty_mutex)); | |
4112 | tty = current->signal->tty; | |
4113 | /* | |
4114 | * session->tty can be changed/cleared from under us, make sure we | |
4115 | * issue the load. The obtained pointer, when not NULL, is valid as | |
4116 | * long as we hold tty_mutex. | |
4117 | */ | |
4118 | barrier(); | |
4119 | return tty; | |
4120 | } | |
a311f743 | 4121 | EXPORT_SYMBOL_GPL(get_current_tty); |
1da177e4 LT |
4122 | |
4123 | /* | |
4124 | * Initialize the console device. This is called *early*, so | |
4125 | * we can't necessarily depend on lots of kernel help here. | |
4126 | * Just do some early initializations, and do the complex setup | |
4127 | * later. | |
4128 | */ | |
4129 | void __init console_init(void) | |
4130 | { | |
4131 | initcall_t *call; | |
4132 | ||
4133 | /* Setup the default TTY line discipline. */ | |
4134 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); | |
4135 | ||
4136 | /* | |
37bdfb07 | 4137 | * set up the console device so that later boot sequences can |
1da177e4 LT |
4138 | * inform about problems etc.. |
4139 | */ | |
1da177e4 LT |
4140 | call = __con_initcall_start; |
4141 | while (call < __con_initcall_end) { | |
4142 | (*call)(); | |
4143 | call++; | |
4144 | } | |
4145 | } | |
4146 | ||
1da177e4 LT |
4147 | static int __init tty_class_init(void) |
4148 | { | |
7fe845d1 | 4149 | tty_class = class_create(THIS_MODULE, "tty"); |
1da177e4 LT |
4150 | if (IS_ERR(tty_class)) |
4151 | return PTR_ERR(tty_class); | |
4152 | return 0; | |
4153 | } | |
4154 | ||
4155 | postcore_initcall(tty_class_init); | |
4156 | ||
4157 | /* 3/2004 jmc: why do these devices exist? */ | |
4158 | ||
4159 | static struct cdev tty_cdev, console_cdev; | |
4160 | #ifdef CONFIG_UNIX98_PTYS | |
4161 | static struct cdev ptmx_cdev; | |
4162 | #endif | |
4163 | #ifdef CONFIG_VT | |
4164 | static struct cdev vc0_cdev; | |
4165 | #endif | |
4166 | ||
4167 | /* | |
4168 | * Ok, now we can initialize the rest of the tty devices and can count | |
4169 | * on memory allocations, interrupts etc.. | |
4170 | */ | |
4171 | static int __init tty_init(void) | |
4172 | { | |
4173 | cdev_init(&tty_cdev, &tty_fops); | |
4174 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || | |
4175 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) | |
4176 | panic("Couldn't register /dev/tty driver\n"); | |
01107d34 | 4177 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), "tty"); |
1da177e4 LT |
4178 | |
4179 | cdev_init(&console_cdev, &console_fops); | |
4180 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || | |
4181 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) | |
4182 | panic("Couldn't register /dev/console driver\n"); | |
01107d34 | 4183 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), "console"); |
1da177e4 LT |
4184 | |
4185 | #ifdef CONFIG_UNIX98_PTYS | |
4186 | cdev_init(&ptmx_cdev, &ptmx_fops); | |
4187 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || | |
4188 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) | |
4189 | panic("Couldn't register /dev/ptmx driver\n"); | |
01107d34 | 4190 | device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), "ptmx"); |
1da177e4 LT |
4191 | #endif |
4192 | ||
4193 | #ifdef CONFIG_VT | |
4194 | cdev_init(&vc0_cdev, &console_fops); | |
4195 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || | |
4196 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) | |
4197 | panic("Couldn't register /dev/tty0 driver\n"); | |
01107d34 | 4198 | device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), "tty0"); |
1da177e4 LT |
4199 | |
4200 | vty_init(); | |
4201 | #endif | |
4202 | return 0; | |
4203 | } | |
4204 | module_init(tty_init); |