1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 1992 obz under the linux copyright
4 *
5 * Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
6 * Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
7 * Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
8 * Some code moved for less code duplication - Andi Kleen - Mar 1997
9 * Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
10 */
11
12 #include <linux/types.h>
13 #include <linux/errno.h>
14 #include <linux/sched/signal.h>
15 #include <linux/tty.h>
16 #include <linux/timer.h>
17 #include <linux/kernel.h>
18 #include <linux/compat.h>
19 #include <linux/module.h>
20 #include <linux/kd.h>
21 #include <linux/vt.h>
22 #include <linux/string.h>
23 #include <linux/slab.h>
24 #include <linux/major.h>
25 #include <linux/fs.h>
26 #include <linux/console.h>
27 #include <linux/consolemap.h>
28 #include <linux/signal.h>
29 #include <linux/suspend.h>
30 #include <linux/timex.h>
31
32 #include <asm/io.h>
33 #include <linux/uaccess.h>
34
35 #include <linux/nospec.h>
36
37 #include <linux/kbd_kern.h>
38 #include <linux/vt_kern.h>
39 #include <linux/kbd_diacr.h>
40 #include <linux/selection.h>
41
42 bool vt_dont_switch;
43
vt_in_use(unsigned int i)44 static inline bool vt_in_use(unsigned int i)
45 {
46 const struct vc_data *vc = vc_cons[i].d;
47
48 /*
49 * console_lock must be held to prevent the vc from being deallocated
50 * while we're checking whether it's in-use.
51 */
52 WARN_CONSOLE_UNLOCKED();
53
54 return vc && kref_read(&vc->port.kref) > 1;
55 }
56
vt_busy(int i)57 static inline bool vt_busy(int i)
58 {
59 if (vt_in_use(i))
60 return true;
61 if (i == fg_console)
62 return true;
63 if (vc_is_sel(vc_cons[i].d))
64 return true;
65
66 return false;
67 }
68
69 /*
70 * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
71 * experimentation and study of X386 SYSV handling.
72 *
73 * One point of difference: SYSV vt's are /dev/vtX, which X >= 0, and
74 * /dev/console is a separate ttyp. Under Linux, /dev/tty0 is /dev/console,
75 * and the vc start at /dev/ttyX, X >= 1. We maintain that here, so we will
76 * always treat our set of vt as numbered 1..MAX_NR_CONSOLES (corresponding to
77 * ttys 0..MAX_NR_CONSOLES-1). Explicitly naming VT 0 is illegal, but using
78 * /dev/tty0 (fg_console) as a target is legal, since an implicit aliasing
79 * to the current console is done by the main ioctl code.
80 */
81
82 #ifdef CONFIG_X86
83 #include <asm/syscalls.h>
84 #endif
85
86 static void complete_change_console(struct vc_data *vc);
87
88 /*
89 * User space VT_EVENT handlers
90 */
91
92 struct vt_event_wait {
93 struct list_head list;
94 struct vt_event event;
95 int done;
96 };
97
98 static LIST_HEAD(vt_events);
99 static DEFINE_SPINLOCK(vt_event_lock);
100 static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);
101
102 /**
103 * vt_event_post
104 * @event: the event that occurred
105 * @old: old console
106 * @new: new console
107 *
108 * Post an VT event to interested VT handlers
109 */
110
vt_event_post(unsigned int event,unsigned int old,unsigned int new)111 void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
112 {
113 struct list_head *pos, *head;
114 unsigned long flags;
115 int wake = 0;
116
117 spin_lock_irqsave(&vt_event_lock, flags);
118 head = &vt_events;
119
120 list_for_each(pos, head) {
121 struct vt_event_wait *ve = list_entry(pos,
122 struct vt_event_wait, list);
123 if (!(ve->event.event & event))
124 continue;
125 ve->event.event = event;
126 /* kernel view is consoles 0..n-1, user space view is
127 console 1..n with 0 meaning current, so we must bias */
128 ve->event.oldev = old + 1;
129 ve->event.newev = new + 1;
130 wake = 1;
131 ve->done = 1;
132 }
133 spin_unlock_irqrestore(&vt_event_lock, flags);
134 if (wake)
135 wake_up_interruptible(&vt_event_waitqueue);
136 }
137
__vt_event_queue(struct vt_event_wait * vw)138 static void __vt_event_queue(struct vt_event_wait *vw)
139 {
140 unsigned long flags;
141 /* Prepare the event */
142 INIT_LIST_HEAD(&vw->list);
143 vw->done = 0;
144 /* Queue our event */
145 spin_lock_irqsave(&vt_event_lock, flags);
146 list_add(&vw->list, &vt_events);
147 spin_unlock_irqrestore(&vt_event_lock, flags);
148 }
149
__vt_event_wait(struct vt_event_wait * vw)150 static void __vt_event_wait(struct vt_event_wait *vw)
151 {
152 /* Wait for it to pass */
153 wait_event_interruptible(vt_event_waitqueue, vw->done);
154 }
155
__vt_event_dequeue(struct vt_event_wait * vw)156 static void __vt_event_dequeue(struct vt_event_wait *vw)
157 {
158 unsigned long flags;
159
160 /* Dequeue it */
161 spin_lock_irqsave(&vt_event_lock, flags);
162 list_del(&vw->list);
163 spin_unlock_irqrestore(&vt_event_lock, flags);
164 }
165
166 /**
167 * vt_event_wait - wait for an event
168 * @vw: our event
169 *
170 * Waits for an event to occur which completes our vt_event_wait
171 * structure. On return the structure has wv->done set to 1 for success
172 * or 0 if some event such as a signal ended the wait.
173 */
174
vt_event_wait(struct vt_event_wait * vw)175 static void vt_event_wait(struct vt_event_wait *vw)
176 {
177 __vt_event_queue(vw);
178 __vt_event_wait(vw);
179 __vt_event_dequeue(vw);
180 }
181
182 /**
183 * vt_event_wait_ioctl - event ioctl handler
184 * @event: argument to ioctl (the event)
185 *
186 * Implement the VT_WAITEVENT ioctl using the VT event interface
187 */
188
vt_event_wait_ioctl(struct vt_event __user * event)189 static int vt_event_wait_ioctl(struct vt_event __user *event)
190 {
191 struct vt_event_wait vw;
192
193 if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
194 return -EFAULT;
195 /* Highest supported event for now */
196 if (vw.event.event & ~VT_MAX_EVENT)
197 return -EINVAL;
198
199 vt_event_wait(&vw);
200 /* If it occurred report it */
201 if (vw.done) {
202 if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
203 return -EFAULT;
204 return 0;
205 }
206 return -EINTR;
207 }
208
209 /**
210 * vt_waitactive - active console wait
211 * @n: new console
212 *
213 * Helper for event waits. Used to implement the legacy
214 * event waiting ioctls in terms of events
215 */
216
vt_waitactive(int n)217 int vt_waitactive(int n)
218 {
219 struct vt_event_wait vw;
220 do {
221 vw.event.event = VT_EVENT_SWITCH;
222 __vt_event_queue(&vw);
223 if (n == fg_console + 1) {
224 __vt_event_dequeue(&vw);
225 break;
226 }
227 __vt_event_wait(&vw);
228 __vt_event_dequeue(&vw);
229 if (vw.done == 0)
230 return -EINTR;
231 } while (vw.event.newev != n);
232 return 0;
233 }
234
235 /*
236 * these are the valid i/o ports we're allowed to change. they map all the
237 * video ports
238 */
239 #define GPFIRST 0x3b4
240 #define GPLAST 0x3df
241 #define GPNUM (GPLAST - GPFIRST + 1)
242
243 /*
244 * currently, setting the mode from KD_TEXT to KD_GRAPHICS doesn't do a whole
245 * lot. i'm not sure if it should do any restoration of modes or what...
246 *
247 * XXX It should at least call into the driver, fbdev's definitely need to
248 * restore their engine state. --BenH
249 *
250 * Called with the console lock held.
251 */
vt_kdsetmode(struct vc_data * vc,unsigned long mode)252 static int vt_kdsetmode(struct vc_data *vc, unsigned long mode)
253 {
254 switch (mode) {
255 case KD_GRAPHICS:
256 break;
257 case KD_TEXT0:
258 case KD_TEXT1:
259 mode = KD_TEXT;
260 fallthrough;
261 case KD_TEXT:
262 break;
263 default:
264 return -EINVAL;
265 }
266
267 if (vc->vc_mode == mode)
268 return 0;
269
270 vc->vc_mode = mode;
271 if (vc->vc_num != fg_console)
272 return 0;
273
274 /* explicitly blank/unblank the screen if switching modes */
275 if (mode == KD_TEXT)
276 do_unblank_screen(1);
277 else
278 do_blank_screen(1);
279
280 return 0;
281 }
282
vt_k_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg,bool perm)283 static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd,
284 unsigned long arg, bool perm)
285 {
286 struct vc_data *vc = tty->driver_data;
287 void __user *up = (void __user *)arg;
288 unsigned int console = vc->vc_num;
289 int ret;
290
291 switch (cmd) {
292 case KIOCSOUND:
293 if (!perm)
294 return -EPERM;
295 /*
296 * The use of PIT_TICK_RATE is historic, it used to be
297 * the platform-dependent CLOCK_TICK_RATE between 2.6.12
298 * and 2.6.36, which was a minor but unfortunate ABI
299 * change. kd_mksound is locked by the input layer.
300 */
301 if (arg)
302 arg = PIT_TICK_RATE / arg;
303 kd_mksound(arg, 0);
304 break;
305
306 case KDMKTONE:
307 if (!perm)
308 return -EPERM;
309 {
310 unsigned int ticks, count;
311
312 /*
313 * Generate the tone for the appropriate number of ticks.
314 * If the time is zero, turn off sound ourselves.
315 */
316 ticks = msecs_to_jiffies((arg >> 16) & 0xffff);
317 count = ticks ? (arg & 0xffff) : 0;
318 if (count)
319 count = PIT_TICK_RATE / count;
320 kd_mksound(count, ticks);
321 break;
322 }
323
324 case KDGKBTYPE:
325 /*
326 * this is naïve.
327 */
328 return put_user(KB_101, (char __user *)arg);
329
330 /*
331 * These cannot be implemented on any machine that implements
332 * ioperm() in user level (such as Alpha PCs) or not at all.
333 *
334 * XXX: you should never use these, just call ioperm directly..
335 */
336 #ifdef CONFIG_X86
337 case KDADDIO:
338 case KDDELIO:
339 /*
340 * KDADDIO and KDDELIO may be able to add ports beyond what
341 * we reject here, but to be safe...
342 *
343 * These are locked internally via sys_ioperm
344 */
345 if (arg < GPFIRST || arg > GPLAST)
346 return -EINVAL;
347
348 return ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
349
350 case KDENABIO:
351 case KDDISABIO:
352 return ksys_ioperm(GPFIRST, GPNUM,
353 (cmd == KDENABIO)) ? -ENXIO : 0;
354 #endif
355
356 /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
357
358 case KDKBDREP:
359 {
360 struct kbd_repeat kbrep;
361
362 if (!capable(CAP_SYS_TTY_CONFIG))
363 return -EPERM;
364
365 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat)))
366 return -EFAULT;
367
368 ret = kbd_rate(&kbrep);
369 if (ret)
370 return ret;
371 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
372 return -EFAULT;
373 break;
374 }
375
376 case KDSETMODE:
377 if (!perm)
378 return -EPERM;
379
380 console_lock();
381 ret = vt_kdsetmode(vc, arg);
382 console_unlock();
383 return ret;
384
385 case KDGETMODE:
386 return put_user(vc->vc_mode, (int __user *)arg);
387
388 case KDMAPDISP:
389 case KDUNMAPDISP:
390 /*
391 * these work like a combination of mmap and KDENABIO.
392 * this could be easily finished.
393 */
394 return -EINVAL;
395
396 case KDSKBMODE:
397 if (!perm)
398 return -EPERM;
399 ret = vt_do_kdskbmode(console, arg);
400 if (ret)
401 return ret;
402 tty_ldisc_flush(tty);
403 break;
404
405 case KDGKBMODE:
406 return put_user(vt_do_kdgkbmode(console), (int __user *)arg);
407
408 /* this could be folded into KDSKBMODE, but for compatibility
409 reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
410 case KDSKBMETA:
411 return vt_do_kdskbmeta(console, arg);
412
413 case KDGKBMETA:
414 /* FIXME: should review whether this is worth locking */
415 return put_user(vt_do_kdgkbmeta(console), (int __user *)arg);
416
417 case KDGETKEYCODE:
418 case KDSETKEYCODE:
419 if(!capable(CAP_SYS_TTY_CONFIG))
420 perm = 0;
421 return vt_do_kbkeycode_ioctl(cmd, up, perm);
422
423 case KDGKBENT:
424 case KDSKBENT:
425 return vt_do_kdsk_ioctl(cmd, up, perm, console);
426
427 case KDGKBSENT:
428 case KDSKBSENT:
429 return vt_do_kdgkb_ioctl(cmd, up, perm);
430
431 /* Diacritical processing. Handled in keyboard.c as it has
432 to operate on the keyboard locks and structures */
433 case KDGKBDIACR:
434 case KDGKBDIACRUC:
435 case KDSKBDIACR:
436 case KDSKBDIACRUC:
437 return vt_do_diacrit(cmd, up, perm);
438
439 /* the ioctls below read/set the flags usually shown in the leds */
440 /* don't use them - they will go away without warning */
441 case KDGKBLED:
442 case KDSKBLED:
443 case KDGETLED:
444 case KDSETLED:
445 return vt_do_kdskled(console, cmd, arg, perm);
446
447 /*
448 * A process can indicate its willingness to accept signals
449 * generated by pressing an appropriate key combination.
450 * Thus, one can have a daemon that e.g. spawns a new console
451 * upon a keypress and then changes to it.
452 * See also the kbrequest field of inittab(5).
453 */
454 case KDSIGACCEPT:
455 if (!perm || !capable(CAP_KILL))
456 return -EPERM;
457 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
458 return -EINVAL;
459
460 spin_lock_irq(&vt_spawn_con.lock);
461 put_pid(vt_spawn_con.pid);
462 vt_spawn_con.pid = get_pid(task_pid(current));
463 vt_spawn_con.sig = arg;
464 spin_unlock_irq(&vt_spawn_con.lock);
465 break;
466
467 case KDFONTOP: {
468 struct console_font_op op;
469
470 if (copy_from_user(&op, up, sizeof(op)))
471 return -EFAULT;
472 if (!perm && op.op != KD_FONT_OP_GET)
473 return -EPERM;
474 ret = con_font_op(vc, &op);
475 if (ret)
476 return ret;
477 if (copy_to_user(up, &op, sizeof(op)))
478 return -EFAULT;
479 break;
480 }
481
482 default:
483 return -ENOIOCTLCMD;
484 }
485
486 return 0;
487 }
488
do_unimap_ioctl(int cmd,struct unimapdesc __user * user_ud,bool perm,struct vc_data * vc)489 static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
490 bool perm, struct vc_data *vc)
491 {
492 struct unimapdesc tmp;
493
494 if (copy_from_user(&tmp, user_ud, sizeof tmp))
495 return -EFAULT;
496 switch (cmd) {
497 case PIO_UNIMAP:
498 if (!perm)
499 return -EPERM;
500 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
501 case GIO_UNIMAP:
502 if (!perm && fg_console != vc->vc_num)
503 return -EPERM;
504 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct),
505 tmp.entries);
506 }
507 return 0;
508 }
509
vt_io_ioctl(struct vc_data * vc,unsigned int cmd,void __user * up,bool perm)510 static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
511 bool perm)
512 {
513 switch (cmd) {
514 case PIO_CMAP:
515 if (!perm)
516 return -EPERM;
517 return con_set_cmap(up);
518
519 case GIO_CMAP:
520 return con_get_cmap(up);
521
522 case PIO_SCRNMAP:
523 if (!perm)
524 return -EPERM;
525 return con_set_trans_old(up);
526
527 case GIO_SCRNMAP:
528 return con_get_trans_old(up);
529
530 case PIO_UNISCRNMAP:
531 if (!perm)
532 return -EPERM;
533 return con_set_trans_new(up);
534
535 case GIO_UNISCRNMAP:
536 return con_get_trans_new(up);
537
538 case PIO_UNIMAPCLR:
539 if (!perm)
540 return -EPERM;
541 con_clear_unimap(vc);
542 break;
543
544 case PIO_UNIMAP:
545 case GIO_UNIMAP:
546 return do_unimap_ioctl(cmd, up, perm, vc);
547
548 default:
549 return -ENOIOCTLCMD;
550 }
551
552 return 0;
553 }
554
vt_reldisp(struct vc_data * vc,unsigned int swtch)555 static int vt_reldisp(struct vc_data *vc, unsigned int swtch)
556 {
557 int newvt, ret;
558
559 if (vc->vt_mode.mode != VT_PROCESS)
560 return -EINVAL;
561
562 /* Switched-to response */
563 if (vc->vt_newvt < 0) {
564 /* If it's just an ACK, ignore it */
565 return swtch == VT_ACKACQ ? 0 : -EINVAL;
566 }
567
568 /* Switching-from response */
569 if (swtch == 0) {
570 /* Switch disallowed, so forget we were trying to do it. */
571 vc->vt_newvt = -1;
572 return 0;
573 }
574
575 /* The current vt has been released, so complete the switch. */
576 newvt = vc->vt_newvt;
577 vc->vt_newvt = -1;
578 ret = vc_allocate(newvt);
579 if (ret)
580 return ret;
581
582 /*
583 * When we actually do the console switch, make sure we are atomic with
584 * respect to other console switches..
585 */
586 complete_change_console(vc_cons[newvt].d);
587
588 return 0;
589 }
590
vt_setactivate(struct vt_setactivate __user * sa)591 static int vt_setactivate(struct vt_setactivate __user *sa)
592 {
593 struct vt_setactivate vsa;
594 struct vc_data *nvc;
595 int ret;
596
597 if (copy_from_user(&vsa, sa, sizeof(vsa)))
598 return -EFAULT;
599 if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
600 return -ENXIO;
601
602 vsa.console--;
603 vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES);
604 console_lock();
605 ret = vc_allocate(vsa.console);
606 if (ret) {
607 console_unlock();
608 return ret;
609 }
610
611 /*
612 * This is safe providing we don't drop the console sem between
613 * vc_allocate and finishing referencing nvc.
614 */
615 nvc = vc_cons[vsa.console].d;
616 nvc->vt_mode = vsa.mode;
617 nvc->vt_mode.frsig = 0;
618 put_pid(nvc->vt_pid);
619 nvc->vt_pid = get_pid(task_pid(current));
620 console_unlock();
621
622 /* Commence switch and lock */
623 /* Review set_console locks */
624 set_console(vsa.console);
625
626 return 0;
627 }
628
629 /* deallocate a single console, if possible (leave 0) */
vt_disallocate(unsigned int vc_num)630 static int vt_disallocate(unsigned int vc_num)
631 {
632 struct vc_data *vc = NULL;
633 int ret = 0;
634
635 console_lock();
636 if (vt_busy(vc_num))
637 ret = -EBUSY;
638 else if (vc_num)
639 vc = vc_deallocate(vc_num);
640 console_unlock();
641
642 if (vc && vc_num >= MIN_NR_CONSOLES)
643 tty_port_put(&vc->port);
644
645 return ret;
646 }
647
648 /* deallocate all unused consoles, but leave 0 */
vt_disallocate_all(void)649 static void vt_disallocate_all(void)
650 {
651 struct vc_data *vc[MAX_NR_CONSOLES];
652 int i;
653
654 console_lock();
655 for (i = 1; i < MAX_NR_CONSOLES; i++)
656 if (!vt_busy(i))
657 vc[i] = vc_deallocate(i);
658 else
659 vc[i] = NULL;
660 console_unlock();
661
662 for (i = 1; i < MAX_NR_CONSOLES; i++) {
663 if (vc[i] && i >= MIN_NR_CONSOLES)
664 tty_port_put(&vc[i]->port);
665 }
666 }
667
vt_resizex(struct vc_data * vc,struct vt_consize __user * cs)668 static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
669 {
670 struct vt_consize v;
671 int i;
672
673 if (copy_from_user(&v, cs, sizeof(struct vt_consize)))
674 return -EFAULT;
675
676 /* FIXME: Should check the copies properly */
677 if (!v.v_vlin)
678 v.v_vlin = vc->vc_scan_lines;
679
680 if (v.v_clin) {
681 int rows = v.v_vlin / v.v_clin;
682 if (v.v_rows != rows) {
683 if (v.v_rows) /* Parameters don't add up */
684 return -EINVAL;
685 v.v_rows = rows;
686 }
687 }
688
689 if (v.v_vcol && v.v_ccol) {
690 int cols = v.v_vcol / v.v_ccol;
691 if (v.v_cols != cols) {
692 if (v.v_cols)
693 return -EINVAL;
694 v.v_cols = cols;
695 }
696 }
697
698 if (v.v_clin > 32)
699 return -EINVAL;
700
701 for (i = 0; i < MAX_NR_CONSOLES; i++) {
702 struct vc_data *vcp;
703
704 if (!vc_cons[i].d)
705 continue;
706 console_lock();
707 vcp = vc_cons[i].d;
708 if (vcp) {
709 int ret;
710 int save_scan_lines = vcp->vc_scan_lines;
711 int save_cell_height = vcp->vc_cell_height;
712
713 if (v.v_vlin)
714 vcp->vc_scan_lines = v.v_vlin;
715 if (v.v_clin)
716 vcp->vc_cell_height = v.v_clin;
717 vcp->vc_resize_user = 1;
718 ret = vc_resize(vcp, v.v_cols, v.v_rows);
719 if (ret) {
720 vcp->vc_scan_lines = save_scan_lines;
721 vcp->vc_cell_height = save_cell_height;
722 console_unlock();
723 return ret;
724 }
725 }
726 console_unlock();
727 }
728
729 return 0;
730 }
731
732 /*
733 * We handle the console-specific ioctl's here. We allow the
734 * capability to modify any console, not just the fg_console.
735 */
vt_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)736 int vt_ioctl(struct tty_struct *tty,
737 unsigned int cmd, unsigned long arg)
738 {
739 struct vc_data *vc = tty->driver_data;
740 void __user *up = (void __user *)arg;
741 int i, perm;
742 int ret;
743
744 /*
745 * To have permissions to do most of the vt ioctls, we either have
746 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
747 */
748 perm = 0;
749 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
750 perm = 1;
751
752 ret = vt_k_ioctl(tty, cmd, arg, perm);
753 if (ret != -ENOIOCTLCMD)
754 return ret;
755
756 ret = vt_io_ioctl(vc, cmd, up, perm);
757 if (ret != -ENOIOCTLCMD)
758 return ret;
759
760 switch (cmd) {
761 case TIOCLINUX:
762 return tioclinux(tty, arg);
763 case VT_SETMODE:
764 {
765 struct vt_mode tmp;
766
767 if (!perm)
768 return -EPERM;
769 if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
770 return -EFAULT;
771 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
772 return -EINVAL;
773
774 console_lock();
775 vc->vt_mode = tmp;
776 /* the frsig is ignored, so we set it to 0 */
777 vc->vt_mode.frsig = 0;
778 put_pid(vc->vt_pid);
779 vc->vt_pid = get_pid(task_pid(current));
780 /* no switch is required -- saw@shade.msu.ru */
781 vc->vt_newvt = -1;
782 console_unlock();
783 break;
784 }
785
786 case VT_GETMODE:
787 {
788 struct vt_mode tmp;
789 int rc;
790
791 console_lock();
792 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
793 console_unlock();
794
795 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
796 if (rc)
797 return -EFAULT;
798 break;
799 }
800
801 /*
802 * Returns global vt state. Note that VT 0 is always open, since
803 * it's an alias for the current VT, and people can't use it here.
804 * We cannot return state for more than 16 VTs, since v_state is short.
805 */
806 case VT_GETSTATE:
807 {
808 struct vt_stat __user *vtstat = up;
809 unsigned short state, mask;
810
811 if (put_user(fg_console + 1, &vtstat->v_active))
812 return -EFAULT;
813
814 state = 1; /* /dev/tty0 is always open */
815 console_lock(); /* required by vt_in_use() */
816 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
817 ++i, mask <<= 1)
818 if (vt_in_use(i))
819 state |= mask;
820 console_unlock();
821 return put_user(state, &vtstat->v_state);
822 }
823
824 /*
825 * Returns the first available (non-opened) console.
826 */
827 case VT_OPENQRY:
828 console_lock(); /* required by vt_in_use() */
829 for (i = 0; i < MAX_NR_CONSOLES; ++i)
830 if (!vt_in_use(i))
831 break;
832 console_unlock();
833 i = i < MAX_NR_CONSOLES ? (i+1) : -1;
834 return put_user(i, (int __user *)arg);
835
836 /*
837 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
838 * with num >= 1 (switches to vt 0, our console, are not allowed, just
839 * to preserve sanity).
840 */
841 case VT_ACTIVATE:
842 if (!perm)
843 return -EPERM;
844 if (arg == 0 || arg > MAX_NR_CONSOLES)
845 return -ENXIO;
846
847 arg--;
848 arg = array_index_nospec(arg, MAX_NR_CONSOLES);
849 console_lock();
850 ret = vc_allocate(arg);
851 console_unlock();
852 if (ret)
853 return ret;
854 set_console(arg);
855 break;
856
857 case VT_SETACTIVATE:
858 if (!perm)
859 return -EPERM;
860
861 return vt_setactivate(up);
862
863 /*
864 * wait until the specified VT has been activated
865 */
866 case VT_WAITACTIVE:
867 if (!perm)
868 return -EPERM;
869 if (arg == 0 || arg > MAX_NR_CONSOLES)
870 return -ENXIO;
871 return vt_waitactive(arg);
872
873 /*
874 * If a vt is under process control, the kernel will not switch to it
875 * immediately, but postpone the operation until the process calls this
876 * ioctl, allowing the switch to complete.
877 *
878 * According to the X sources this is the behavior:
879 * 0: pending switch-from not OK
880 * 1: pending switch-from OK
881 * 2: completed switch-to OK
882 */
883 case VT_RELDISP:
884 if (!perm)
885 return -EPERM;
886
887 console_lock();
888 ret = vt_reldisp(vc, arg);
889 console_unlock();
890
891 return ret;
892
893
894 /*
895 * Disallocate memory associated to VT (but leave VT1)
896 */
897 case VT_DISALLOCATE:
898 if (arg > MAX_NR_CONSOLES)
899 return -ENXIO;
900
901 if (arg == 0) {
902 vt_disallocate_all();
903 break;
904 }
905
906 arg = array_index_nospec(arg - 1, MAX_NR_CONSOLES);
907 return vt_disallocate(arg);
908
909 case VT_RESIZE:
910 {
911 struct vt_sizes __user *vtsizes = up;
912 struct vc_data *vc;
913 ushort ll,cc;
914
915 if (!perm)
916 return -EPERM;
917 if (get_user(ll, &vtsizes->v_rows) ||
918 get_user(cc, &vtsizes->v_cols))
919 return -EFAULT;
920
921 console_lock();
922 for (i = 0; i < MAX_NR_CONSOLES; i++) {
923 vc = vc_cons[i].d;
924
925 if (vc) {
926 vc->vc_resize_user = 1;
927 /* FIXME: review v tty lock */
928 vc_resize(vc_cons[i].d, cc, ll);
929 }
930 }
931 console_unlock();
932 break;
933 }
934
935 case VT_RESIZEX:
936 if (!perm)
937 return -EPERM;
938
939 return vt_resizex(vc, up);
940
941 case VT_LOCKSWITCH:
942 if (!capable(CAP_SYS_TTY_CONFIG))
943 return -EPERM;
944 vt_dont_switch = true;
945 break;
946 case VT_UNLOCKSWITCH:
947 if (!capable(CAP_SYS_TTY_CONFIG))
948 return -EPERM;
949 vt_dont_switch = false;
950 break;
951 case VT_GETHIFONTMASK:
952 return put_user(vc->vc_hi_font_mask,
953 (unsigned short __user *)arg);
954 case VT_WAITEVENT:
955 return vt_event_wait_ioctl((struct vt_event __user *)arg);
956 default:
957 return -ENOIOCTLCMD;
958 }
959
960 return 0;
961 }
962
reset_vc(struct vc_data * vc)963 void reset_vc(struct vc_data *vc)
964 {
965 vc->vc_mode = KD_TEXT;
966 vt_reset_unicode(vc->vc_num);
967 vc->vt_mode.mode = VT_AUTO;
968 vc->vt_mode.waitv = 0;
969 vc->vt_mode.relsig = 0;
970 vc->vt_mode.acqsig = 0;
971 vc->vt_mode.frsig = 0;
972 put_pid(vc->vt_pid);
973 vc->vt_pid = NULL;
974 vc->vt_newvt = -1;
975 reset_palette(vc);
976 }
977
vc_SAK(struct work_struct * work)978 void vc_SAK(struct work_struct *work)
979 {
980 struct vc *vc_con =
981 container_of(work, struct vc, SAK_work);
982 struct vc_data *vc;
983 struct tty_struct *tty;
984
985 console_lock();
986 vc = vc_con->d;
987 if (vc) {
988 /* FIXME: review tty ref counting */
989 tty = vc->port.tty;
990 /*
991 * SAK should also work in all raw modes and reset
992 * them properly.
993 */
994 if (tty)
995 __do_SAK(tty);
996 reset_vc(vc);
997 }
998 console_unlock();
999 }
1000
1001 #ifdef CONFIG_COMPAT
1002
1003 struct compat_console_font_op {
1004 compat_uint_t op; /* operation code KD_FONT_OP_* */
1005 compat_uint_t flags; /* KD_FONT_FLAG_* */
1006 compat_uint_t width, height; /* font size */
1007 compat_uint_t charcount;
1008 compat_caddr_t data; /* font data with height fixed to 32 */
1009 };
1010
1011 static inline int
compat_kdfontop_ioctl(struct compat_console_font_op __user * fontop,int perm,struct console_font_op * op,struct vc_data * vc)1012 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1013 int perm, struct console_font_op *op, struct vc_data *vc)
1014 {
1015 int i;
1016
1017 if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1018 return -EFAULT;
1019 if (!perm && op->op != KD_FONT_OP_GET)
1020 return -EPERM;
1021 op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1022 i = con_font_op(vc, op);
1023 if (i)
1024 return i;
1025 ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1026 if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1027 return -EFAULT;
1028 return 0;
1029 }
1030
1031 struct compat_unimapdesc {
1032 unsigned short entry_ct;
1033 compat_caddr_t entries;
1034 };
1035
1036 static inline int
compat_unimap_ioctl(unsigned int cmd,struct compat_unimapdesc __user * user_ud,int perm,struct vc_data * vc)1037 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1038 int perm, struct vc_data *vc)
1039 {
1040 struct compat_unimapdesc tmp;
1041 struct unipair __user *tmp_entries;
1042
1043 if (copy_from_user(&tmp, user_ud, sizeof tmp))
1044 return -EFAULT;
1045 tmp_entries = compat_ptr(tmp.entries);
1046 switch (cmd) {
1047 case PIO_UNIMAP:
1048 if (!perm)
1049 return -EPERM;
1050 return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1051 case GIO_UNIMAP:
1052 if (!perm && fg_console != vc->vc_num)
1053 return -EPERM;
1054 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1055 }
1056 return 0;
1057 }
1058
vt_compat_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)1059 long vt_compat_ioctl(struct tty_struct *tty,
1060 unsigned int cmd, unsigned long arg)
1061 {
1062 struct vc_data *vc = tty->driver_data;
1063 struct console_font_op op; /* used in multiple places here */
1064 void __user *up = compat_ptr(arg);
1065 int perm;
1066
1067 /*
1068 * To have permissions to do most of the vt ioctls, we either have
1069 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1070 */
1071 perm = 0;
1072 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1073 perm = 1;
1074
1075 switch (cmd) {
1076 /*
1077 * these need special handlers for incompatible data structures
1078 */
1079
1080 case KDFONTOP:
1081 return compat_kdfontop_ioctl(up, perm, &op, vc);
1082
1083 case PIO_UNIMAP:
1084 case GIO_UNIMAP:
1085 return compat_unimap_ioctl(cmd, up, perm, vc);
1086
1087 /*
1088 * all these treat 'arg' as an integer
1089 */
1090 case KIOCSOUND:
1091 case KDMKTONE:
1092 #ifdef CONFIG_X86
1093 case KDADDIO:
1094 case KDDELIO:
1095 #endif
1096 case KDSETMODE:
1097 case KDMAPDISP:
1098 case KDUNMAPDISP:
1099 case KDSKBMODE:
1100 case KDSKBMETA:
1101 case KDSKBLED:
1102 case KDSETLED:
1103 case KDSIGACCEPT:
1104 case VT_ACTIVATE:
1105 case VT_WAITACTIVE:
1106 case VT_RELDISP:
1107 case VT_DISALLOCATE:
1108 case VT_RESIZE:
1109 case VT_RESIZEX:
1110 return vt_ioctl(tty, cmd, arg);
1111
1112 /*
1113 * the rest has a compatible data structure behind arg,
1114 * but we have to convert it to a proper 64 bit pointer.
1115 */
1116 default:
1117 return vt_ioctl(tty, cmd, (unsigned long)up);
1118 }
1119 }
1120
1121
1122 #endif /* CONFIG_COMPAT */
1123
1124
1125 /*
1126 * Performs the back end of a vt switch. Called under the console
1127 * semaphore.
1128 */
complete_change_console(struct vc_data * vc)1129 static void complete_change_console(struct vc_data *vc)
1130 {
1131 unsigned char old_vc_mode;
1132 int old = fg_console;
1133
1134 last_console = fg_console;
1135
1136 /*
1137 * If we're switching, we could be going from KD_GRAPHICS to
1138 * KD_TEXT mode or vice versa, which means we need to blank or
1139 * unblank the screen later.
1140 */
1141 old_vc_mode = vc_cons[fg_console].d->vc_mode;
1142 switch_screen(vc);
1143
1144 /*
1145 * This can't appear below a successful kill_pid(). If it did,
1146 * then the *blank_screen operation could occur while X, having
1147 * received acqsig, is waking up on another processor. This
1148 * condition can lead to overlapping accesses to the VGA range
1149 * and the framebuffer (causing system lockups).
1150 *
1151 * To account for this we duplicate this code below only if the
1152 * controlling process is gone and we've called reset_vc.
1153 */
1154 if (old_vc_mode != vc->vc_mode) {
1155 if (vc->vc_mode == KD_TEXT)
1156 do_unblank_screen(1);
1157 else
1158 do_blank_screen(1);
1159 }
1160
1161 /*
1162 * If this new console is under process control, send it a signal
1163 * telling it that it has acquired. Also check if it has died and
1164 * clean up (similar to logic employed in change_console())
1165 */
1166 if (vc->vt_mode.mode == VT_PROCESS) {
1167 /*
1168 * Send the signal as privileged - kill_pid() will
1169 * tell us if the process has gone or something else
1170 * is awry
1171 */
1172 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1173 /*
1174 * The controlling process has died, so we revert back to
1175 * normal operation. In this case, we'll also change back
1176 * to KD_TEXT mode. I'm not sure if this is strictly correct
1177 * but it saves the agony when the X server dies and the screen
1178 * remains blanked due to KD_GRAPHICS! It would be nice to do
1179 * this outside of VT_PROCESS but there is no single process
1180 * to account for and tracking tty count may be undesirable.
1181 */
1182 reset_vc(vc);
1183
1184 if (old_vc_mode != vc->vc_mode) {
1185 if (vc->vc_mode == KD_TEXT)
1186 do_unblank_screen(1);
1187 else
1188 do_blank_screen(1);
1189 }
1190 }
1191 }
1192
1193 /*
1194 * Wake anyone waiting for their VT to activate
1195 */
1196 vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1197 return;
1198 }
1199
1200 /*
1201 * Performs the front-end of a vt switch
1202 */
change_console(struct vc_data * new_vc)1203 void change_console(struct vc_data *new_vc)
1204 {
1205 struct vc_data *vc;
1206
1207 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1208 return;
1209
1210 /*
1211 * If this vt is in process mode, then we need to handshake with
1212 * that process before switching. Essentially, we store where that
1213 * vt wants to switch to and wait for it to tell us when it's done
1214 * (via VT_RELDISP ioctl).
1215 *
1216 * We also check to see if the controlling process still exists.
1217 * If it doesn't, we reset this vt to auto mode and continue.
1218 * This is a cheap way to track process control. The worst thing
1219 * that can happen is: we send a signal to a process, it dies, and
1220 * the switch gets "lost" waiting for a response; hopefully, the
1221 * user will try again, we'll detect the process is gone (unless
1222 * the user waits just the right amount of time :-) and revert the
1223 * vt to auto control.
1224 */
1225 vc = vc_cons[fg_console].d;
1226 if (vc->vt_mode.mode == VT_PROCESS) {
1227 /*
1228 * Send the signal as privileged - kill_pid() will
1229 * tell us if the process has gone or something else
1230 * is awry.
1231 *
1232 * We need to set vt_newvt *before* sending the signal or we
1233 * have a race.
1234 */
1235 vc->vt_newvt = new_vc->vc_num;
1236 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1237 /*
1238 * It worked. Mark the vt to switch to and
1239 * return. The process needs to send us a
1240 * VT_RELDISP ioctl to complete the switch.
1241 */
1242 return;
1243 }
1244
1245 /*
1246 * The controlling process has died, so we revert back to
1247 * normal operation. In this case, we'll also change back
1248 * to KD_TEXT mode. I'm not sure if this is strictly correct
1249 * but it saves the agony when the X server dies and the screen
1250 * remains blanked due to KD_GRAPHICS! It would be nice to do
1251 * this outside of VT_PROCESS but there is no single process
1252 * to account for and tracking tty count may be undesirable.
1253 */
1254 reset_vc(vc);
1255
1256 /*
1257 * Fall through to normal (VT_AUTO) handling of the switch...
1258 */
1259 }
1260
1261 /*
1262 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1263 */
1264 if (vc->vc_mode == KD_GRAPHICS)
1265 return;
1266
1267 complete_change_console(new_vc);
1268 }
1269
1270 /* Perform a kernel triggered VT switch for suspend/resume */
1271
1272 static int disable_vt_switch;
1273
vt_move_to_console(unsigned int vt,int alloc)1274 int vt_move_to_console(unsigned int vt, int alloc)
1275 {
1276 int prev;
1277
1278 console_lock();
1279 /* Graphics mode - up to X */
1280 if (disable_vt_switch) {
1281 console_unlock();
1282 return 0;
1283 }
1284 prev = fg_console;
1285
1286 if (alloc && vc_allocate(vt)) {
1287 /* we can't have a free VC for now. Too bad,
1288 * we don't want to mess the screen for now. */
1289 console_unlock();
1290 return -ENOSPC;
1291 }
1292
1293 if (set_console(vt)) {
1294 /*
1295 * We're unable to switch to the SUSPEND_CONSOLE.
1296 * Let the calling function know so it can decide
1297 * what to do.
1298 */
1299 console_unlock();
1300 return -EIO;
1301 }
1302 console_unlock();
1303 if (vt_waitactive(vt + 1)) {
1304 pr_debug("Suspend: Can't switch VCs.");
1305 return -EINTR;
1306 }
1307 return prev;
1308 }
1309
1310 /*
1311 * Normally during a suspend, we allocate a new console and switch to it.
1312 * When we resume, we switch back to the original console. This switch
1313 * can be slow, so on systems where the framebuffer can handle restoration
1314 * of video registers anyways, there's little point in doing the console
1315 * switch. This function allows you to disable it by passing it '0'.
1316 */
pm_set_vt_switch(int do_switch)1317 void pm_set_vt_switch(int do_switch)
1318 {
1319 console_lock();
1320 disable_vt_switch = !do_switch;
1321 console_unlock();
1322 }
1323 EXPORT_SYMBOL(pm_set_vt_switch);
1324