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 return vt_do_kdskbmeta(console, arg); 410 411 case KDGKBMETA: 412 /* FIXME: should review whether this is worth locking */ 413 return put_user(vt_do_kdgkbmeta(console), (int __user *)arg); 414 415 case KDGETKEYCODE: 416 case KDSETKEYCODE: 417 if(!capable(CAP_SYS_TTY_CONFIG)) 418 perm = 0; 419 return vt_do_kbkeycode_ioctl(cmd, up, perm); 420 421 case KDGKBENT: 422 case KDSKBENT: 423 return vt_do_kdsk_ioctl(cmd, up, perm, console); 424 425 case KDGKBSENT: 426 case KDSKBSENT: 427 return vt_do_kdgkb_ioctl(cmd, up, perm); 428 429 /* Diacritical processing. Handled in keyboard.c as it has 430 to operate on the keyboard locks and structures */ 431 case KDGKBDIACR: 432 case KDGKBDIACRUC: 433 case KDSKBDIACR: 434 case KDSKBDIACRUC: 435 return vt_do_diacrit(cmd, up, perm); 436 437 /* the ioctls below read/set the flags usually shown in the leds */ 438 /* don't use them - they will go away without warning */ 439 case KDGKBLED: 440 case KDSKBLED: 441 case KDGETLED: 442 case KDSETLED: 443 return vt_do_kdskled(console, cmd, arg, perm); 444 445 /* 446 * A process can indicate its willingness to accept signals 447 * generated by pressing an appropriate key combination. 448 * Thus, one can have a daemon that e.g. spawns a new console 449 * upon a keypress and then changes to it. 450 * See also the kbrequest field of inittab(5). 451 */ 452 case KDSIGACCEPT: 453 if (!perm || !capable(CAP_KILL)) 454 return -EPERM; 455 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL) 456 return -EINVAL; 457 458 spin_lock_irq(&vt_spawn_con.lock); 459 put_pid(vt_spawn_con.pid); 460 vt_spawn_con.pid = get_pid(task_pid(current)); 461 vt_spawn_con.sig = arg; 462 spin_unlock_irq(&vt_spawn_con.lock); 463 break; 464 465 case KDFONTOP: { 466 struct console_font_op op; 467 468 if (copy_from_user(&op, up, sizeof(op))) 469 return -EFAULT; 470 if (!perm && op.op != KD_FONT_OP_GET) 471 return -EPERM; 472 ret = con_font_op(vc, &op); 473 if (ret) 474 return ret; 475 if (copy_to_user(up, &op, sizeof(op))) 476 return -EFAULT; 477 break; 478 } 479 480 default: 481 return -ENOIOCTLCMD; 482 } 483 484 return 0; 485 } 486 487 static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, 488 bool perm, struct vc_data *vc) 489 { 490 struct unimapdesc tmp; 491 492 if (copy_from_user(&tmp, user_ud, sizeof tmp)) 493 return -EFAULT; 494 switch (cmd) { 495 case PIO_UNIMAP: 496 if (!perm) 497 return -EPERM; 498 return con_set_unimap(vc, tmp.entry_ct, tmp.entries); 499 case GIO_UNIMAP: 500 if (!perm && fg_console != vc->vc_num) 501 return -EPERM; 502 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), 503 tmp.entries); 504 } 505 return 0; 506 } 507 508 static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up, 509 bool perm) 510 { 511 switch (cmd) { 512 case PIO_CMAP: 513 if (!perm) 514 return -EPERM; 515 return con_set_cmap(up); 516 517 case GIO_CMAP: 518 return con_get_cmap(up); 519 520 case PIO_SCRNMAP: 521 if (!perm) 522 return -EPERM; 523 return con_set_trans_old(up); 524 525 case GIO_SCRNMAP: 526 return con_get_trans_old(up); 527 528 case PIO_UNISCRNMAP: 529 if (!perm) 530 return -EPERM; 531 return con_set_trans_new(up); 532 533 case GIO_UNISCRNMAP: 534 return con_get_trans_new(up); 535 536 case PIO_UNIMAPCLR: 537 if (!perm) 538 return -EPERM; 539 con_clear_unimap(vc); 540 break; 541 542 case PIO_UNIMAP: 543 case GIO_UNIMAP: 544 return do_unimap_ioctl(cmd, up, perm, vc); 545 546 default: 547 return -ENOIOCTLCMD; 548 } 549 550 return 0; 551 } 552 553 static int vt_reldisp(struct vc_data *vc, unsigned int swtch) 554 { 555 int newvt, ret; 556 557 if (vc->vt_mode.mode != VT_PROCESS) 558 return -EINVAL; 559 560 /* Switched-to response */ 561 if (vc->vt_newvt < 0) { 562 /* If it's just an ACK, ignore it */ 563 return swtch == VT_ACKACQ ? 0 : -EINVAL; 564 } 565 566 /* Switching-from response */ 567 if (swtch == 0) { 568 /* Switch disallowed, so forget we were trying to do it. */ 569 vc->vt_newvt = -1; 570 return 0; 571 } 572 573 /* The current vt has been released, so complete the switch. */ 574 newvt = vc->vt_newvt; 575 vc->vt_newvt = -1; 576 ret = vc_allocate(newvt); 577 if (ret) 578 return ret; 579 580 /* 581 * When we actually do the console switch, make sure we are atomic with 582 * respect to other console switches.. 583 */ 584 complete_change_console(vc_cons[newvt].d); 585 586 return 0; 587 } 588 589 static int vt_setactivate(struct vt_setactivate __user *sa) 590 { 591 struct vt_setactivate vsa; 592 struct vc_data *nvc; 593 int ret; 594 595 if (copy_from_user(&vsa, sa, sizeof(vsa))) 596 return -EFAULT; 597 if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES) 598 return -ENXIO; 599 600 vsa.console--; 601 vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES); 602 scoped_guard(console_lock) { 603 ret = vc_allocate(vsa.console); 604 if (ret) 605 return ret; 606 607 /* 608 * This is safe providing we don't drop the console sem between 609 * vc_allocate and finishing referencing nvc. 610 */ 611 nvc = vc_cons[vsa.console].d; 612 nvc->vt_mode = vsa.mode; 613 nvc->vt_mode.frsig = 0; 614 put_pid(nvc->vt_pid); 615 nvc->vt_pid = get_pid(task_pid(current)); 616 } 617 618 /* Commence switch and lock */ 619 /* Review set_console locks */ 620 set_console(vsa.console); 621 622 return 0; 623 } 624 625 /* deallocate a single console, if possible (leave 0) */ 626 static int vt_disallocate(unsigned int vc_num) 627 { 628 struct vc_data *vc = NULL; 629 630 scoped_guard(console_lock) { 631 if (vt_busy(vc_num)) 632 return -EBUSY; 633 if (vc_num) 634 vc = vc_deallocate(vc_num); 635 } 636 637 if (vc && vc_num >= MIN_NR_CONSOLES) 638 tty_port_put(&vc->port); 639 640 return 0; 641 } 642 643 /* deallocate all unused consoles, but leave 0 */ 644 static void vt_disallocate_all(void) 645 { 646 struct vc_data *vc[MAX_NR_CONSOLES]; 647 int i; 648 649 scoped_guard(console_lock) 650 for (i = 1; i < MAX_NR_CONSOLES; i++) 651 if (!vt_busy(i)) 652 vc[i] = vc_deallocate(i); 653 else 654 vc[i] = NULL; 655 656 for (i = 1; i < MAX_NR_CONSOLES; i++) { 657 if (vc[i] && i >= MIN_NR_CONSOLES) 658 tty_port_put(&vc[i]->port); 659 } 660 } 661 662 static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs) 663 { 664 struct vt_consize v; 665 int i; 666 667 if (copy_from_user(&v, cs, sizeof(struct vt_consize))) 668 return -EFAULT; 669 670 /* FIXME: Should check the copies properly */ 671 if (!v.v_vlin) 672 v.v_vlin = vc->vc_scan_lines; 673 674 if (v.v_clin) { 675 int rows = v.v_vlin / v.v_clin; 676 if (v.v_rows != rows) { 677 if (v.v_rows) /* Parameters don't add up */ 678 return -EINVAL; 679 v.v_rows = rows; 680 } 681 } 682 683 if (v.v_vcol && v.v_ccol) { 684 int cols = v.v_vcol / v.v_ccol; 685 if (v.v_cols != cols) { 686 if (v.v_cols) 687 return -EINVAL; 688 v.v_cols = cols; 689 } 690 } 691 692 if (v.v_clin > 32) 693 return -EINVAL; 694 695 for (i = 0; i < MAX_NR_CONSOLES; i++) { 696 struct vc_data *vcp; 697 698 if (!vc_cons[i].d) 699 continue; 700 guard(console_lock)(); 701 vcp = vc_cons[i].d; 702 if (vcp) { 703 int ret; 704 int save_scan_lines = vcp->vc_scan_lines; 705 int save_cell_height = vcp->vc_cell_height; 706 707 if (v.v_vlin) 708 vcp->vc_scan_lines = v.v_vlin; 709 if (v.v_clin) 710 vcp->vc_cell_height = v.v_clin; 711 ret = __vc_resize(vcp, v.v_cols, v.v_rows, true); 712 if (ret) { 713 vcp->vc_scan_lines = save_scan_lines; 714 vcp->vc_cell_height = save_cell_height; 715 return ret; 716 } 717 } 718 } 719 720 return 0; 721 } 722 723 /* 724 * We handle the console-specific ioctl's here. We allow the 725 * capability to modify any console, not just the fg_console. 726 */ 727 int vt_ioctl(struct tty_struct *tty, 728 unsigned int cmd, unsigned long arg) 729 { 730 struct vc_data *vc = tty->driver_data; 731 void __user *up = (void __user *)arg; 732 int i, perm; 733 int ret; 734 735 /* 736 * To have permissions to do most of the vt ioctls, we either have 737 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG. 738 */ 739 perm = 0; 740 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG)) 741 perm = 1; 742 743 ret = vt_k_ioctl(tty, cmd, arg, perm); 744 if (ret != -ENOIOCTLCMD) 745 return ret; 746 747 ret = vt_io_ioctl(vc, cmd, up, perm); 748 if (ret != -ENOIOCTLCMD) 749 return ret; 750 751 switch (cmd) { 752 case TIOCLINUX: 753 return tioclinux(tty, arg); 754 case VT_SETMODE: 755 { 756 struct vt_mode tmp; 757 758 if (!perm) 759 return -EPERM; 760 if (copy_from_user(&tmp, up, sizeof(struct vt_mode))) 761 return -EFAULT; 762 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) 763 return -EINVAL; 764 765 guard(console_lock)(); 766 vc->vt_mode = tmp; 767 /* the frsig is ignored, so we set it to 0 */ 768 vc->vt_mode.frsig = 0; 769 put_pid(vc->vt_pid); 770 vc->vt_pid = get_pid(task_pid(current)); 771 /* no switch is required -- saw@shade.msu.ru */ 772 vc->vt_newvt = -1; 773 break; 774 } 775 776 case VT_GETMODE: 777 { 778 struct vt_mode tmp; 779 int rc; 780 781 scoped_guard(console_lock) 782 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode)); 783 784 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode)); 785 if (rc) 786 return -EFAULT; 787 break; 788 } 789 790 /* 791 * Returns global vt state. Note that VT 0 is always open, since 792 * it's an alias for the current VT, and people can't use it here. 793 * We cannot return state for more than 16 VTs, since v_state is short. 794 */ 795 case VT_GETSTATE: 796 { 797 struct vt_stat __user *vtstat = up; 798 unsigned short state, mask; 799 800 if (put_user(fg_console + 1, &vtstat->v_active)) 801 return -EFAULT; 802 803 state = 1; /* /dev/tty0 is always open */ 804 scoped_guard(console_lock) /* required by vt_in_use() */ 805 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask; ++i, mask <<= 1) 806 if (vt_in_use(i)) 807 state |= mask; 808 return put_user(state, &vtstat->v_state); 809 } 810 811 /* 812 * Returns the first available (non-opened) console. 813 */ 814 case VT_OPENQRY: 815 scoped_guard(console_lock) /* required by vt_in_use() */ 816 for (i = 0; i < MAX_NR_CONSOLES; ++i) 817 if (!vt_in_use(i)) 818 break; 819 i = i < MAX_NR_CONSOLES ? (i+1) : -1; 820 return put_user(i, (int __user *)arg); 821 822 /* 823 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num, 824 * with num >= 1 (switches to vt 0, our console, are not allowed, just 825 * to preserve sanity). 826 */ 827 case VT_ACTIVATE: 828 if (!perm) 829 return -EPERM; 830 if (arg == 0 || arg > MAX_NR_CONSOLES) 831 return -ENXIO; 832 833 arg--; 834 arg = array_index_nospec(arg, MAX_NR_CONSOLES); 835 scoped_guard(console_lock) { 836 ret = vc_allocate(arg); 837 if (ret) 838 return ret; 839 } 840 set_console(arg); 841 break; 842 843 case VT_SETACTIVATE: 844 if (!perm) 845 return -EPERM; 846 847 return vt_setactivate(up); 848 849 /* 850 * wait until the specified VT has been activated 851 */ 852 case VT_WAITACTIVE: 853 if (!perm) 854 return -EPERM; 855 if (arg == 0 || arg > MAX_NR_CONSOLES) 856 return -ENXIO; 857 return vt_waitactive(arg); 858 859 /* 860 * If a vt is under process control, the kernel will not switch to it 861 * immediately, but postpone the operation until the process calls this 862 * ioctl, allowing the switch to complete. 863 * 864 * According to the X sources this is the behavior: 865 * 0: pending switch-from not OK 866 * 1: pending switch-from OK 867 * 2: completed switch-to OK 868 */ 869 case VT_RELDISP: 870 { 871 if (!perm) 872 return -EPERM; 873 874 guard(console_lock)(); 875 return vt_reldisp(vc, arg); 876 } 877 878 /* 879 * Disallocate memory associated to VT (but leave VT1) 880 */ 881 case VT_DISALLOCATE: 882 if (arg > MAX_NR_CONSOLES) 883 return -ENXIO; 884 885 if (arg == 0) { 886 vt_disallocate_all(); 887 break; 888 } 889 890 arg = array_index_nospec(arg - 1, MAX_NR_CONSOLES); 891 return vt_disallocate(arg); 892 893 case VT_RESIZE: 894 { 895 struct vt_sizes __user *vtsizes = up; 896 struct vc_data *vc; 897 ushort ll,cc; 898 899 if (!perm) 900 return -EPERM; 901 if (get_user(ll, &vtsizes->v_rows) || 902 get_user(cc, &vtsizes->v_cols)) 903 return -EFAULT; 904 905 guard(console_lock)(); 906 for (i = 0; i < MAX_NR_CONSOLES; i++) { 907 vc = vc_cons[i].d; 908 909 if (vc) { 910 /* FIXME: review v tty lock */ 911 ret = __vc_resize(vc_cons[i].d, cc, ll, true); 912 if (ret) 913 return ret; 914 } 915 } 916 break; 917 } 918 919 case VT_RESIZEX: 920 if (!perm) 921 return -EPERM; 922 923 return vt_resizex(vc, up); 924 925 case VT_LOCKSWITCH: 926 if (!capable(CAP_SYS_TTY_CONFIG)) 927 return -EPERM; 928 vt_dont_switch = true; 929 break; 930 case VT_UNLOCKSWITCH: 931 if (!capable(CAP_SYS_TTY_CONFIG)) 932 return -EPERM; 933 vt_dont_switch = false; 934 break; 935 case VT_GETHIFONTMASK: 936 return put_user(vc->vc_hi_font_mask, 937 (unsigned short __user *)arg); 938 case VT_WAITEVENT: 939 return vt_event_wait_ioctl((struct vt_event __user *)arg); 940 941 case VT_GETCONSIZECSRPOS: 942 { 943 struct vt_consizecsrpos concsr; 944 945 console_lock(); 946 concsr.con_cols = vc->vc_cols; 947 concsr.con_rows = vc->vc_rows; 948 concsr.csr_col = vc->state.x; 949 concsr.csr_row = vc->state.y; 950 console_unlock(); 951 if (copy_to_user(up, &concsr, sizeof(concsr))) 952 return -EFAULT; 953 return 0; 954 } 955 956 default: 957 return -ENOIOCTLCMD; 958 } 959 960 return 0; 961 } 962 963 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 } 977 978 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 guard(console_lock)(); 986 vc = vc_con->d; 987 if (!vc) 988 return; 989 990 /* FIXME: review tty ref counting */ 991 tty = vc->port.tty; 992 /* SAK should also work in all raw modes and reset them properly. */ 993 if (tty) 994 __do_SAK(tty); 995 reset_vc(vc); 996 } 997 998 #ifdef CONFIG_COMPAT 999 1000 struct compat_console_font_op { 1001 compat_uint_t op; /* operation code KD_FONT_OP_* */ 1002 compat_uint_t flags; /* KD_FONT_FLAG_* */ 1003 compat_uint_t width, height; /* font size */ 1004 compat_uint_t charcount; 1005 compat_caddr_t data; /* font data with height fixed to 32 */ 1006 }; 1007 1008 static inline int 1009 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop, 1010 int perm, struct console_font_op *op, struct vc_data *vc) 1011 { 1012 int i; 1013 1014 if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op))) 1015 return -EFAULT; 1016 if (!perm && op->op != KD_FONT_OP_GET) 1017 return -EPERM; 1018 op->data = compat_ptr(((struct compat_console_font_op *)op)->data); 1019 i = con_font_op(vc, op); 1020 if (i) 1021 return i; 1022 ((struct compat_console_font_op *)op)->data = (unsigned long)op->data; 1023 if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op))) 1024 return -EFAULT; 1025 return 0; 1026 } 1027 1028 struct compat_unimapdesc { 1029 unsigned short entry_ct; 1030 compat_caddr_t entries; 1031 }; 1032 1033 static inline int 1034 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud, 1035 int perm, struct vc_data *vc) 1036 { 1037 struct compat_unimapdesc tmp; 1038 struct unipair __user *tmp_entries; 1039 1040 if (copy_from_user(&tmp, user_ud, sizeof tmp)) 1041 return -EFAULT; 1042 tmp_entries = compat_ptr(tmp.entries); 1043 switch (cmd) { 1044 case PIO_UNIMAP: 1045 if (!perm) 1046 return -EPERM; 1047 return con_set_unimap(vc, tmp.entry_ct, tmp_entries); 1048 case GIO_UNIMAP: 1049 if (!perm && fg_console != vc->vc_num) 1050 return -EPERM; 1051 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries); 1052 } 1053 return 0; 1054 } 1055 1056 long vt_compat_ioctl(struct tty_struct *tty, 1057 unsigned int cmd, unsigned long arg) 1058 { 1059 struct vc_data *vc = tty->driver_data; 1060 struct console_font_op op; /* used in multiple places here */ 1061 void __user *up = compat_ptr(arg); 1062 int perm; 1063 1064 /* 1065 * To have permissions to do most of the vt ioctls, we either have 1066 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG. 1067 */ 1068 perm = 0; 1069 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG)) 1070 perm = 1; 1071 1072 switch (cmd) { 1073 /* 1074 * these need special handlers for incompatible data structures 1075 */ 1076 1077 case KDFONTOP: 1078 return compat_kdfontop_ioctl(up, perm, &op, vc); 1079 1080 case PIO_UNIMAP: 1081 case GIO_UNIMAP: 1082 return compat_unimap_ioctl(cmd, up, perm, vc); 1083 1084 /* 1085 * all these treat 'arg' as an integer 1086 */ 1087 case KIOCSOUND: 1088 case KDMKTONE: 1089 #ifdef CONFIG_X86 1090 case KDADDIO: 1091 case KDDELIO: 1092 #endif 1093 case KDSETMODE: 1094 case KDMAPDISP: 1095 case KDUNMAPDISP: 1096 case KDSKBMODE: 1097 case KDSKBMETA: 1098 case KDSKBLED: 1099 case KDSETLED: 1100 case KDSIGACCEPT: 1101 case VT_ACTIVATE: 1102 case VT_WAITACTIVE: 1103 case VT_RELDISP: 1104 case VT_DISALLOCATE: 1105 return vt_ioctl(tty, cmd, arg); 1106 1107 /* 1108 * the rest has a compatible data structure behind arg, 1109 * but we have to convert it to a proper 64 bit pointer. 1110 */ 1111 default: 1112 return vt_ioctl(tty, cmd, (unsigned long)up); 1113 } 1114 } 1115 1116 1117 #endif /* CONFIG_COMPAT */ 1118 1119 1120 /* 1121 * Performs the back end of a vt switch. Called under the console 1122 * semaphore. 1123 */ 1124 static void complete_change_console(struct vc_data *vc) 1125 { 1126 unsigned char old_vc_mode; 1127 int old = fg_console; 1128 1129 last_console = fg_console; 1130 1131 /* 1132 * If we're switching, we could be going from KD_GRAPHICS to 1133 * KD_TEXT mode or vice versa, which means we need to blank or 1134 * unblank the screen later. 1135 */ 1136 old_vc_mode = vc_cons[fg_console].d->vc_mode; 1137 switch_screen(vc); 1138 1139 /* 1140 * This can't appear below a successful kill_pid(). If it did, 1141 * then the *blank_screen operation could occur while X, having 1142 * received acqsig, is waking up on another processor. This 1143 * condition can lead to overlapping accesses to the VGA range 1144 * and the framebuffer (causing system lockups). 1145 * 1146 * To account for this we duplicate this code below only if the 1147 * controlling process is gone and we've called reset_vc. 1148 */ 1149 if (old_vc_mode != vc->vc_mode) { 1150 if (vc->vc_mode == KD_TEXT) 1151 do_unblank_screen(1); 1152 else 1153 do_blank_screen(1); 1154 } 1155 1156 /* 1157 * If this new console is under process control, send it a signal 1158 * telling it that it has acquired. Also check if it has died and 1159 * clean up (similar to logic employed in change_console()) 1160 */ 1161 if (vc->vt_mode.mode == VT_PROCESS) { 1162 /* 1163 * Send the signal as privileged - kill_pid() will 1164 * tell us if the process has gone or something else 1165 * is awry 1166 */ 1167 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) { 1168 /* 1169 * The controlling process has died, so we revert back to 1170 * normal operation. In this case, we'll also change back 1171 * to KD_TEXT mode. I'm not sure if this is strictly correct 1172 * but it saves the agony when the X server dies and the screen 1173 * remains blanked due to KD_GRAPHICS! It would be nice to do 1174 * this outside of VT_PROCESS but there is no single process 1175 * to account for and tracking tty count may be undesirable. 1176 */ 1177 reset_vc(vc); 1178 1179 if (old_vc_mode != vc->vc_mode) { 1180 if (vc->vc_mode == KD_TEXT) 1181 do_unblank_screen(1); 1182 else 1183 do_blank_screen(1); 1184 } 1185 } 1186 } 1187 1188 /* 1189 * Wake anyone waiting for their VT to activate 1190 */ 1191 vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num); 1192 return; 1193 } 1194 1195 /* 1196 * Performs the front-end of a vt switch 1197 */ 1198 void change_console(struct vc_data *new_vc) 1199 { 1200 struct vc_data *vc; 1201 1202 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch) 1203 return; 1204 1205 /* 1206 * If this vt is in process mode, then we need to handshake with 1207 * that process before switching. Essentially, we store where that 1208 * vt wants to switch to and wait for it to tell us when it's done 1209 * (via VT_RELDISP ioctl). 1210 * 1211 * We also check to see if the controlling process still exists. 1212 * If it doesn't, we reset this vt to auto mode and continue. 1213 * This is a cheap way to track process control. The worst thing 1214 * that can happen is: we send a signal to a process, it dies, and 1215 * the switch gets "lost" waiting for a response; hopefully, the 1216 * user will try again, we'll detect the process is gone (unless 1217 * the user waits just the right amount of time :-) and revert the 1218 * vt to auto control. 1219 */ 1220 vc = vc_cons[fg_console].d; 1221 if (vc->vt_mode.mode == VT_PROCESS) { 1222 /* 1223 * Send the signal as privileged - kill_pid() will 1224 * tell us if the process has gone or something else 1225 * is awry. 1226 * 1227 * We need to set vt_newvt *before* sending the signal or we 1228 * have a race. 1229 */ 1230 vc->vt_newvt = new_vc->vc_num; 1231 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) { 1232 /* 1233 * It worked. Mark the vt to switch to and 1234 * return. The process needs to send us a 1235 * VT_RELDISP ioctl to complete the switch. 1236 */ 1237 return; 1238 } 1239 1240 /* 1241 * The controlling process has died, so we revert back to 1242 * normal operation. In this case, we'll also change back 1243 * to KD_TEXT mode. I'm not sure if this is strictly correct 1244 * but it saves the agony when the X server dies and the screen 1245 * remains blanked due to KD_GRAPHICS! It would be nice to do 1246 * this outside of VT_PROCESS but there is no single process 1247 * to account for and tracking tty count may be undesirable. 1248 */ 1249 reset_vc(vc); 1250 1251 /* 1252 * Fall through to normal (VT_AUTO) handling of the switch... 1253 */ 1254 } 1255 1256 /* 1257 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode 1258 */ 1259 if (vc->vc_mode == KD_GRAPHICS) 1260 return; 1261 1262 complete_change_console(new_vc); 1263 } 1264 1265 /* Perform a kernel triggered VT switch for suspend/resume */ 1266 1267 static int disable_vt_switch; 1268 1269 int vt_move_to_console(unsigned int vt, int alloc) 1270 { 1271 int prev; 1272 1273 scoped_guard(console_lock) { 1274 /* Graphics mode - up to X */ 1275 if (disable_vt_switch) 1276 return 0; 1277 1278 prev = fg_console; 1279 1280 if (alloc && vc_allocate(vt)) { 1281 /* 1282 * We can't have a free VC for now. Too bad, we don't want to mess the 1283 * screen for now. 1284 */ 1285 return -ENOSPC; 1286 } 1287 1288 if (set_console(vt)) { 1289 /* 1290 * We're unable to switch to the SUSPEND_CONSOLE. Let the calling function 1291 * know so it can decide what to do. 1292 */ 1293 return -EIO; 1294 } 1295 } 1296 if (vt_waitactive(vt + 1)) { 1297 pr_debug("Suspend: Can't switch VCs."); 1298 return -EINTR; 1299 } 1300 return prev; 1301 } 1302 1303 /* 1304 * Normally during a suspend, we allocate a new console and switch to it. 1305 * When we resume, we switch back to the original console. This switch 1306 * can be slow, so on systems where the framebuffer can handle restoration 1307 * of video registers anyways, there's little point in doing the console 1308 * switch. This function allows you to disable it by passing it '0'. 1309 */ 1310 void pm_set_vt_switch(int do_switch) 1311 { 1312 guard(console_lock)(); 1313 disable_vt_switch = !do_switch; 1314 } 1315 EXPORT_SYMBOL(pm_set_vt_switch); 1316