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 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 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 */ 110 111 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 } 137 138 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 } 149 150 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 } 155 156 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 */ 174 175 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 */ 188 189 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 */ 216 217 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 */ 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 } 282 283 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 guard(console_lock)(); 381 return vt_kdsetmode(vc, arg); 382 } 383 case KDGETMODE: 384 return put_user(vc->vc_mode, (int __user *)arg); 385 386 case KDMAPDISP: 387 case KDUNMAPDISP: 388 /* 389 * these work like a combination of mmap and KDENABIO. 390 * this could be easily finished. 391 */ 392 return -EINVAL; 393 394 case KDSKBMODE: 395 if (!perm) 396 return -EPERM; 397 ret = vt_do_kdskbmode(console, arg); 398 if (ret) 399 return ret; 400 tty_ldisc_flush(tty); 401 break; 402 403 case KDGKBMODE: 404 return put_user(vt_do_kdgkbmode(console), (int __user *)arg); 405 406 /* this could be folded into KDSKBMODE, but for compatibility 407 reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */ 408 case KDSKBMETA: 409 if (!perm) 410 return -EPERM; 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 } 488 489 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 } 509 510 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 } 554 555 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 } 590 591 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 if (vsa.mode.mode != VT_AUTO && vsa.mode.mode != VT_PROCESS) 602 return -EINVAL; 603 604 vsa.console--; 605 vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES); 606 scoped_guard(console_lock) { 607 ret = vc_allocate(vsa.console); 608 if (ret) 609 return ret; 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 } 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) */ 630 static int vt_disallocate(unsigned int vc_num) 631 { 632 struct vc_data *vc = NULL; 633 634 scoped_guard(console_lock) { 635 if (vt_busy(vc_num)) 636 return -EBUSY; 637 if (vc_num) 638 vc = vc_deallocate(vc_num); 639 } 640 641 if (vc && vc_num >= MIN_NR_CONSOLES) 642 tty_port_put(&vc->port); 643 644 return 0; 645 } 646 647 /* deallocate all unused consoles, but leave 0 */ 648 static void vt_disallocate_all(void) 649 { 650 struct vc_data *vc[MAX_NR_CONSOLES]; 651 int i; 652 653 scoped_guard(console_lock) 654 for (i = 1; i < MAX_NR_CONSOLES; i++) 655 if (!vt_busy(i)) 656 vc[i] = vc_deallocate(i); 657 else 658 vc[i] = NULL; 659 660 for (i = 1; i < MAX_NR_CONSOLES; i++) { 661 if (vc[i] && i >= MIN_NR_CONSOLES) 662 tty_port_put(&vc[i]->port); 663 } 664 } 665 666 static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs) 667 { 668 struct vt_consize v; 669 int i; 670 671 if (copy_from_user(&v, cs, sizeof(struct vt_consize))) 672 return -EFAULT; 673 674 /* FIXME: Should check the copies properly */ 675 if (!v.v_vlin) 676 v.v_vlin = vc->vc_scan_lines; 677 678 if (v.v_clin) { 679 int rows = v.v_vlin / v.v_clin; 680 if (v.v_rows != rows) { 681 if (v.v_rows) /* Parameters don't add up */ 682 return -EINVAL; 683 v.v_rows = rows; 684 } 685 } 686 687 if (v.v_vcol && v.v_ccol) { 688 int cols = v.v_vcol / v.v_ccol; 689 if (v.v_cols != cols) { 690 if (v.v_cols) 691 return -EINVAL; 692 v.v_cols = cols; 693 } 694 } 695 696 if (v.v_clin > 32) 697 return -EINVAL; 698 699 for (i = 0; i < MAX_NR_CONSOLES; i++) { 700 struct vc_data *vcp; 701 702 if (!vc_cons[i].d) 703 continue; 704 guard(console_lock)(); 705 vcp = vc_cons[i].d; 706 if (vcp) { 707 int ret; 708 int save_scan_lines = vcp->vc_scan_lines; 709 int save_cell_height = vcp->vc_cell_height; 710 711 if (v.v_vlin) 712 vcp->vc_scan_lines = v.v_vlin; 713 if (v.v_clin) 714 vcp->vc_cell_height = v.v_clin; 715 ret = __vc_resize(vcp, v.v_cols, v.v_rows, true); 716 if (ret) { 717 vcp->vc_scan_lines = save_scan_lines; 718 vcp->vc_cell_height = save_cell_height; 719 return ret; 720 } 721 } 722 } 723 724 return 0; 725 } 726 727 /* 728 * We handle the console-specific ioctl's here. We allow the 729 * capability to modify any console, not just the fg_console. 730 */ 731 int vt_ioctl(struct tty_struct *tty, 732 unsigned int cmd, unsigned long arg) 733 { 734 struct vc_data *vc = tty->driver_data; 735 void __user *up = (void __user *)arg; 736 int i, perm; 737 int ret; 738 739 /* 740 * To have permissions to do most of the vt ioctls, we either have 741 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG. 742 */ 743 perm = 0; 744 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG)) 745 perm = 1; 746 747 ret = vt_k_ioctl(tty, cmd, arg, perm); 748 if (ret != -ENOIOCTLCMD) 749 return ret; 750 751 ret = vt_io_ioctl(vc, cmd, up, perm); 752 if (ret != -ENOIOCTLCMD) 753 return ret; 754 755 switch (cmd) { 756 case TIOCLINUX: 757 return tioclinux(tty, arg); 758 case VT_SETMODE: 759 { 760 struct vt_mode tmp; 761 762 if (!perm) 763 return -EPERM; 764 if (copy_from_user(&tmp, up, sizeof(struct vt_mode))) 765 return -EFAULT; 766 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) 767 return -EINVAL; 768 769 guard(console_lock)(); 770 vc->vt_mode = tmp; 771 /* the frsig is ignored, so we set it to 0 */ 772 vc->vt_mode.frsig = 0; 773 put_pid(vc->vt_pid); 774 vc->vt_pid = get_pid(task_pid(current)); 775 /* no switch is required -- saw@shade.msu.ru */ 776 vc->vt_newvt = -1; 777 break; 778 } 779 780 case VT_GETMODE: 781 { 782 struct vt_mode tmp; 783 int rc; 784 785 scoped_guard(console_lock) 786 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode)); 787 788 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode)); 789 if (rc) 790 return -EFAULT; 791 break; 792 } 793 794 /* 795 * Returns global vt state. Note that VT 0 is always open, since 796 * it's an alias for the current VT, and people can't use it here. 797 * We cannot return state for more than 16 VTs, since v_state is short. 798 */ 799 case VT_GETSTATE: 800 { 801 struct vt_stat __user *vtstat = up; 802 unsigned short state, mask; 803 804 if (put_user(fg_console + 1, &vtstat->v_active)) 805 return -EFAULT; 806 807 state = 1; /* /dev/tty0 is always open */ 808 scoped_guard(console_lock) /* required by vt_in_use() */ 809 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask; ++i, mask <<= 1) 810 if (vt_in_use(i)) 811 state |= mask; 812 return put_user(state, &vtstat->v_state); 813 } 814 815 /* 816 * Returns the first available (non-opened) console. 817 */ 818 case VT_OPENQRY: 819 scoped_guard(console_lock) /* required by vt_in_use() */ 820 for (i = 0; i < MAX_NR_CONSOLES; ++i) 821 if (!vt_in_use(i)) 822 break; 823 i = i < MAX_NR_CONSOLES ? (i+1) : -1; 824 return put_user(i, (int __user *)arg); 825 826 /* 827 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num, 828 * with num >= 1 (switches to vt 0, our console, are not allowed, just 829 * to preserve sanity). 830 */ 831 case VT_ACTIVATE: 832 if (!perm) 833 return -EPERM; 834 if (arg == 0 || arg > MAX_NR_CONSOLES) 835 return -ENXIO; 836 837 arg--; 838 arg = array_index_nospec(arg, MAX_NR_CONSOLES); 839 scoped_guard(console_lock) { 840 ret = vc_allocate(arg); 841 if (ret) 842 return ret; 843 } 844 set_console(arg); 845 break; 846 847 case VT_SETACTIVATE: 848 if (!perm) 849 return -EPERM; 850 851 return vt_setactivate(up); 852 853 /* 854 * wait until the specified VT has been activated 855 */ 856 case VT_WAITACTIVE: 857 if (!perm) 858 return -EPERM; 859 if (arg == 0 || arg > MAX_NR_CONSOLES) 860 return -ENXIO; 861 return vt_waitactive(arg); 862 863 /* 864 * If a vt is under process control, the kernel will not switch to it 865 * immediately, but postpone the operation until the process calls this 866 * ioctl, allowing the switch to complete. 867 * 868 * According to the X sources this is the behavior: 869 * 0: pending switch-from not OK 870 * 1: pending switch-from OK 871 * 2: completed switch-to OK 872 */ 873 case VT_RELDISP: 874 { 875 if (!perm) 876 return -EPERM; 877 878 guard(console_lock)(); 879 return vt_reldisp(vc, arg); 880 } 881 882 /* 883 * Disallocate memory associated to VT (but leave VT1) 884 */ 885 case VT_DISALLOCATE: 886 if (arg > MAX_NR_CONSOLES) 887 return -ENXIO; 888 889 if (arg == 0) { 890 vt_disallocate_all(); 891 break; 892 } 893 894 arg = array_index_nospec(arg - 1, MAX_NR_CONSOLES); 895 return vt_disallocate(arg); 896 897 case VT_RESIZE: 898 { 899 struct vt_sizes __user *vtsizes = up; 900 struct vc_data *vc; 901 ushort ll,cc; 902 903 if (!perm) 904 return -EPERM; 905 if (get_user(ll, &vtsizes->v_rows) || 906 get_user(cc, &vtsizes->v_cols)) 907 return -EFAULT; 908 909 guard(console_lock)(); 910 for (i = 0; i < MAX_NR_CONSOLES; i++) { 911 vc = vc_cons[i].d; 912 913 if (vc) { 914 /* FIXME: review v tty lock */ 915 ret = __vc_resize(vc_cons[i].d, cc, ll, true); 916 if (ret) 917 return ret; 918 } 919 } 920 break; 921 } 922 923 case VT_RESIZEX: 924 if (!perm) 925 return -EPERM; 926 927 return vt_resizex(vc, up); 928 929 case VT_LOCKSWITCH: 930 if (!capable(CAP_SYS_TTY_CONFIG)) 931 return -EPERM; 932 vt_dont_switch = true; 933 break; 934 case VT_UNLOCKSWITCH: 935 if (!capable(CAP_SYS_TTY_CONFIG)) 936 return -EPERM; 937 vt_dont_switch = false; 938 break; 939 case VT_GETHIFONTMASK: 940 return put_user(vc->vc_hi_font_mask, 941 (unsigned short __user *)arg); 942 case VT_WAITEVENT: 943 return vt_event_wait_ioctl((struct vt_event __user *)arg); 944 945 case VT_GETCONSIZECSRPOS: 946 { 947 struct vt_consizecsrpos concsr; 948 949 console_lock(); 950 concsr.con_cols = vc->vc_cols; 951 concsr.con_rows = vc->vc_rows; 952 concsr.csr_col = vc->state.x; 953 concsr.csr_row = vc->state.y; 954 console_unlock(); 955 if (copy_to_user(up, &concsr, sizeof(concsr))) 956 return -EFAULT; 957 return 0; 958 } 959 960 default: 961 return -ENOIOCTLCMD; 962 } 963 964 return 0; 965 } 966 967 void reset_vc(struct vc_data *vc) 968 { 969 vc->vc_mode = KD_TEXT; 970 vt_reset_unicode(vc->vc_num); 971 vc->vt_mode.mode = VT_AUTO; 972 vc->vt_mode.waitv = 0; 973 vc->vt_mode.relsig = 0; 974 vc->vt_mode.acqsig = 0; 975 vc->vt_mode.frsig = 0; 976 put_pid(vc->vt_pid); 977 vc->vt_pid = NULL; 978 vc->vt_newvt = -1; 979 reset_palette(vc); 980 } 981 982 void vc_SAK(struct work_struct *work) 983 { 984 struct vc *vc_con = 985 container_of(work, struct vc, SAK_work); 986 struct vc_data *vc; 987 struct tty_struct *tty; 988 989 guard(console_lock)(); 990 vc = vc_con->d; 991 if (!vc) 992 return; 993 994 /* FIXME: review tty ref counting */ 995 tty = vc->port.tty; 996 /* SAK should also work in all raw modes and reset them properly. */ 997 if (tty) 998 __do_SAK(tty); 999 reset_vc(vc); 1000 } 1001 1002 #ifdef CONFIG_COMPAT 1003 1004 struct compat_console_font_op { 1005 compat_uint_t op; /* operation code KD_FONT_OP_* */ 1006 compat_uint_t flags; /* KD_FONT_FLAG_* */ 1007 compat_uint_t width, height; /* font size */ 1008 compat_uint_t charcount; 1009 compat_caddr_t data; /* font data with height fixed to 32 */ 1010 }; 1011 1012 static inline int 1013 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop, 1014 int perm, struct console_font_op *op, struct vc_data *vc) 1015 { 1016 int i; 1017 1018 if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op))) 1019 return -EFAULT; 1020 if (!perm && op->op != KD_FONT_OP_GET) 1021 return -EPERM; 1022 op->data = compat_ptr(((struct compat_console_font_op *)op)->data); 1023 i = con_font_op(vc, op); 1024 if (i) 1025 return i; 1026 ((struct compat_console_font_op *)op)->data = (unsigned long)op->data; 1027 if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op))) 1028 return -EFAULT; 1029 return 0; 1030 } 1031 1032 struct compat_unimapdesc { 1033 unsigned short entry_ct; 1034 compat_caddr_t entries; 1035 }; 1036 1037 static inline int 1038 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud, 1039 int perm, struct vc_data *vc) 1040 { 1041 struct compat_unimapdesc tmp; 1042 struct unipair __user *tmp_entries; 1043 1044 if (copy_from_user(&tmp, user_ud, sizeof tmp)) 1045 return -EFAULT; 1046 tmp_entries = compat_ptr(tmp.entries); 1047 switch (cmd) { 1048 case PIO_UNIMAP: 1049 if (!perm) 1050 return -EPERM; 1051 return con_set_unimap(vc, tmp.entry_ct, tmp_entries); 1052 case GIO_UNIMAP: 1053 if (!perm && fg_console != vc->vc_num) 1054 return -EPERM; 1055 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries); 1056 } 1057 return 0; 1058 } 1059 1060 long vt_compat_ioctl(struct tty_struct *tty, 1061 unsigned int cmd, unsigned long arg) 1062 { 1063 struct vc_data *vc = tty->driver_data; 1064 struct console_font_op op; /* used in multiple places here */ 1065 void __user *up = compat_ptr(arg); 1066 int perm; 1067 1068 /* 1069 * To have permissions to do most of the vt ioctls, we either have 1070 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG. 1071 */ 1072 perm = 0; 1073 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG)) 1074 perm = 1; 1075 1076 switch (cmd) { 1077 /* 1078 * these need special handlers for incompatible data structures 1079 */ 1080 1081 case KDFONTOP: 1082 return compat_kdfontop_ioctl(up, perm, &op, vc); 1083 1084 case PIO_UNIMAP: 1085 case GIO_UNIMAP: 1086 return compat_unimap_ioctl(cmd, up, perm, vc); 1087 1088 /* 1089 * all these treat 'arg' as an integer 1090 */ 1091 case KIOCSOUND: 1092 case KDMKTONE: 1093 #ifdef CONFIG_X86 1094 case KDADDIO: 1095 case KDDELIO: 1096 #endif 1097 case KDSETMODE: 1098 case KDMAPDISP: 1099 case KDUNMAPDISP: 1100 case KDSKBMODE: 1101 case KDSKBMETA: 1102 case KDSKBLED: 1103 case KDSETLED: 1104 case KDSIGACCEPT: 1105 case VT_ACTIVATE: 1106 case VT_WAITACTIVE: 1107 case VT_RELDISP: 1108 case VT_DISALLOCATE: 1109 return vt_ioctl(tty, cmd, arg); 1110 1111 /* 1112 * the rest has a compatible data structure behind arg, 1113 * but we have to convert it to a proper 64 bit pointer. 1114 */ 1115 default: 1116 return vt_ioctl(tty, cmd, (unsigned long)up); 1117 } 1118 } 1119 1120 1121 #endif /* CONFIG_COMPAT */ 1122 1123 1124 /* 1125 * Performs the back end of a vt switch. Called under the console 1126 * semaphore. 1127 */ 1128 static void complete_change_console(struct vc_data *vc) 1129 { 1130 unsigned char old_vc_mode; 1131 int old = fg_console; 1132 1133 last_console = fg_console; 1134 1135 /* 1136 * If we're switching, we could be going from KD_GRAPHICS to 1137 * KD_TEXT mode or vice versa, which means we need to blank or 1138 * unblank the screen later. 1139 */ 1140 old_vc_mode = vc_cons[fg_console].d->vc_mode; 1141 switch_screen(vc); 1142 1143 /* 1144 * This can't appear below a successful kill_pid(). If it did, 1145 * then the *blank_screen operation could occur while X, having 1146 * received acqsig, is waking up on another processor. This 1147 * condition can lead to overlapping accesses to the VGA range 1148 * and the framebuffer (causing system lockups). 1149 * 1150 * To account for this we duplicate this code below only if the 1151 * controlling process is gone and we've called reset_vc. 1152 */ 1153 if (old_vc_mode != vc->vc_mode) { 1154 if (vc->vc_mode == KD_TEXT) 1155 do_unblank_screen(1); 1156 else 1157 do_blank_screen(1); 1158 } 1159 1160 /* 1161 * If this new console is under process control, send it a signal 1162 * telling it that it has acquired. Also check if it has died and 1163 * clean up (similar to logic employed in change_console()) 1164 */ 1165 if (vc->vt_mode.mode == VT_PROCESS) { 1166 /* 1167 * Send the signal as privileged - kill_pid() will 1168 * tell us if the process has gone or something else 1169 * is awry 1170 */ 1171 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) { 1172 /* 1173 * The controlling process has died, so we revert back to 1174 * normal operation. In this case, we'll also change back 1175 * to KD_TEXT mode. I'm not sure if this is strictly correct 1176 * but it saves the agony when the X server dies and the screen 1177 * remains blanked due to KD_GRAPHICS! It would be nice to do 1178 * this outside of VT_PROCESS but there is no single process 1179 * to account for and tracking tty count may be undesirable. 1180 */ 1181 reset_vc(vc); 1182 1183 if (old_vc_mode != vc->vc_mode) { 1184 if (vc->vc_mode == KD_TEXT) 1185 do_unblank_screen(1); 1186 else 1187 do_blank_screen(1); 1188 } 1189 } 1190 } 1191 1192 /* 1193 * Wake anyone waiting for their VT to activate 1194 */ 1195 vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num); 1196 return; 1197 } 1198 1199 /* 1200 * Performs the front-end of a vt switch 1201 */ 1202 void change_console(struct vc_data *new_vc) 1203 { 1204 struct vc_data *vc; 1205 1206 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch) 1207 return; 1208 1209 /* 1210 * If this vt is in process mode, then we need to handshake with 1211 * that process before switching. Essentially, we store where that 1212 * vt wants to switch to and wait for it to tell us when it's done 1213 * (via VT_RELDISP ioctl). 1214 * 1215 * We also check to see if the controlling process still exists. 1216 * If it doesn't, we reset this vt to auto mode and continue. 1217 * This is a cheap way to track process control. The worst thing 1218 * that can happen is: we send a signal to a process, it dies, and 1219 * the switch gets "lost" waiting for a response; hopefully, the 1220 * user will try again, we'll detect the process is gone (unless 1221 * the user waits just the right amount of time :-) and revert the 1222 * vt to auto control. 1223 */ 1224 vc = vc_cons[fg_console].d; 1225 if (vc->vt_mode.mode == VT_PROCESS) { 1226 /* 1227 * Send the signal as privileged - kill_pid() will 1228 * tell us if the process has gone or something else 1229 * is awry. 1230 * 1231 * We need to set vt_newvt *before* sending the signal or we 1232 * have a race. 1233 */ 1234 vc->vt_newvt = new_vc->vc_num; 1235 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) { 1236 /* 1237 * It worked. Mark the vt to switch to and 1238 * return. The process needs to send us a 1239 * VT_RELDISP ioctl to complete the switch. 1240 */ 1241 return; 1242 } 1243 1244 /* 1245 * The controlling process has died, so we revert back to 1246 * normal operation. In this case, we'll also change back 1247 * to KD_TEXT mode. I'm not sure if this is strictly correct 1248 * but it saves the agony when the X server dies and the screen 1249 * remains blanked due to KD_GRAPHICS! It would be nice to do 1250 * this outside of VT_PROCESS but there is no single process 1251 * to account for and tracking tty count may be undesirable. 1252 */ 1253 reset_vc(vc); 1254 1255 /* 1256 * Fall through to normal (VT_AUTO) handling of the switch... 1257 */ 1258 } 1259 1260 /* 1261 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode 1262 */ 1263 if (vc->vc_mode == KD_GRAPHICS) 1264 return; 1265 1266 complete_change_console(new_vc); 1267 } 1268 1269 /* Perform a kernel triggered VT switch for suspend/resume */ 1270 1271 static int disable_vt_switch; 1272 1273 int vt_move_to_console(unsigned int vt, int alloc) 1274 { 1275 int prev; 1276 1277 scoped_guard(console_lock) { 1278 /* Graphics mode - up to X */ 1279 if (disable_vt_switch) 1280 return 0; 1281 1282 prev = fg_console; 1283 1284 if (alloc && vc_allocate(vt)) { 1285 /* 1286 * We can't have a free VC for now. Too bad, we don't want to mess the 1287 * screen for now. 1288 */ 1289 return -ENOSPC; 1290 } 1291 1292 if (set_console(vt)) { 1293 /* 1294 * We're unable to switch to the SUSPEND_CONSOLE. Let the calling function 1295 * know so it can decide what to do. 1296 */ 1297 return -EIO; 1298 } 1299 } 1300 if (vt_waitactive(vt + 1)) { 1301 pr_debug("Suspend: Can't switch VCs."); 1302 return -EINTR; 1303 } 1304 return prev; 1305 } 1306 1307 /* 1308 * Normally during a suspend, we allocate a new console and switch to it. 1309 * When we resume, we switch back to the original console. This switch 1310 * can be slow, so on systems where the framebuffer can handle restoration 1311 * of video registers anyways, there's little point in doing the console 1312 * switch. This function allows you to disable it by passing it '0'. 1313 */ 1314 void pm_set_vt_switch(int do_switch) 1315 { 1316 guard(console_lock)(); 1317 disable_vt_switch = !do_switch; 1318 } 1319 EXPORT_SYMBOL(pm_set_vt_switch); 1320