Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/tty_cons.c
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1 /* 2 * Copyright (c) 1988 University of Utah. 3 * Copyright (c) 1991 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the Systems Programming Group of the University of Utah Computer 8 * Science Department. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: @(#)cons.c 7.2 (Berkeley) 5/9/91 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD: releng/5.2/sys/kern/tty_cons.c 121204 2003-10-18 12:16:17Z phk $"); 43 44 #include "opt_ddb.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/conf.h> 49 #include <sys/cons.h> 50 #include <sys/fcntl.h> 51 #include <sys/kernel.h> 52 #include <sys/malloc.h> 53 #include <sys/msgbuf.h> 54 #include <sys/namei.h> 55 #include <sys/proc.h> 56 #include <sys/queue.h> 57 #include <sys/reboot.h> 58 #include <sys/sysctl.h> 59 #include <sys/tty.h> 60 #include <sys/uio.h> 61 #include <sys/vnode.h> 62 63 #include <ddb/ddb.h> 64 65 #include <machine/cpu.h> 66 67 static d_open_t cnopen; 68 static d_close_t cnclose; 69 static d_read_t cnread; 70 static d_write_t cnwrite; 71 static d_ioctl_t cnioctl; 72 static d_poll_t cnpoll; 73 static d_kqfilter_t cnkqfilter; 74 75 static struct cdevsw cn_cdevsw = { 76 .d_open = cnopen, 77 .d_close = cnclose, 78 .d_read = cnread, 79 .d_write = cnwrite, 80 .d_ioctl = cnioctl, 81 .d_poll = cnpoll, 82 .d_name = "console", 83 .d_maj = 256, 84 /* 85 * XXX: We really want major #0, but zero here means 86 * XXX: allocate a major number automatically. 87 * XXX: kern_conf.c knows what to do when it sees 256. 88 */ 89 .d_flags = D_TTY, 90 .d_kqfilter = cnkqfilter, 91 }; 92 93 struct cn_device { 94 STAILQ_ENTRY(cn_device) cnd_next; 95 struct vnode *cnd_vp; 96 struct consdev *cnd_cn; 97 }; 98 99 #define CNDEVPATHMAX 32 100 #define CNDEVTAB_SIZE 4 101 static struct cn_device cn_devtab[CNDEVTAB_SIZE]; 102 static STAILQ_HEAD(, cn_device) cn_devlist = 103 STAILQ_HEAD_INITIALIZER(cn_devlist); 104 105 #define CND_INVALID(cnd, td) \ 106 (cnd == NULL || cnd->cnd_vp == NULL || \ 107 (cnd->cnd_vp->v_type == VBAD && !cn_devopen(cnd, td, 1))) 108 109 static udev_t cn_udev_t; 110 SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD, 111 &cn_udev_t, sizeof cn_udev_t, "T,dev_t", ""); 112 113 int cons_unavail = 0; /* XXX: 114 * physical console not available for 115 * input (i.e., it is in graphics mode) 116 */ 117 static int cn_mute; 118 static int openflag; /* how /dev/console was opened */ 119 static int cn_is_open; 120 static char *consbuf; /* buffer used by `consmsgbuf' */ 121 static struct callout conscallout; /* callout for outputting to constty */ 122 struct msgbuf consmsgbuf; /* message buffer for console tty */ 123 static u_char console_pausing; /* pause after each line during probe */ 124 static char *console_pausestr= 125 "<pause; press any key to proceed to next line or '.' to end pause mode>"; 126 struct tty *constty; /* pointer to console "window" tty */ 127 128 void cndebug(char *); 129 static void constty_timeout(void *arg); 130 131 CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL); 132 SET_DECLARE(cons_set, struct consdev); 133 134 void 135 cninit(void) 136 { 137 struct consdev *best_cn, *cn, **list; 138 139 /* 140 * Check if we should mute the console (for security reasons perhaps) 141 * It can be changes dynamically using sysctl kern.consmute 142 * once we are up and going. 143 * 144 */ 145 cn_mute = ((boothowto & (RB_MUTE 146 |RB_SINGLE 147 |RB_VERBOSE 148 |RB_ASKNAME 149 |RB_CONFIG)) == RB_MUTE); 150 151 /* 152 * Find the first console with the highest priority. 153 */ 154 best_cn = NULL; 155 SET_FOREACH(list, cons_set) { 156 cn = *list; 157 cnremove(cn); 158 if (cn->cn_probe == NULL) 159 continue; 160 cn->cn_probe(cn); 161 if (cn->cn_pri == CN_DEAD) 162 continue; 163 if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri) 164 best_cn = cn; 165 if (boothowto & RB_MULTIPLE) { 166 /* 167 * Initialize console, and attach to it. 168 */ 169 cnadd(cn); 170 cn->cn_init(cn); 171 } 172 } 173 if (best_cn == NULL) 174 return; 175 if ((boothowto & RB_MULTIPLE) == 0) { 176 cnadd(best_cn); 177 best_cn->cn_init(best_cn); 178 } 179 if (boothowto & RB_PAUSE) 180 console_pausing = 1; 181 /* 182 * Make the best console the preferred console. 183 */ 184 cnselect(best_cn); 185 } 186 187 void 188 cninit_finish() 189 { 190 console_pausing = 0; 191 } 192 193 /* add a new physical console to back the virtual console */ 194 int 195 cnadd(struct consdev *cn) 196 { 197 struct cn_device *cnd; 198 int i; 199 200 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) 201 if (cnd->cnd_cn == cn) 202 return (0); 203 for (i = 0; i < CNDEVTAB_SIZE; i++) { 204 cnd = &cn_devtab[i]; 205 if (cnd->cnd_cn == NULL) 206 break; 207 } 208 if (cnd->cnd_cn != NULL) 209 return (ENOMEM); 210 cnd->cnd_cn = cn; 211 if (cn->cn_name[0] == '\0') { 212 /* XXX: it is unclear if/where this print might output */ 213 printf("WARNING: console at %p has no name\n", cn); 214 } 215 STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next); 216 return (0); 217 } 218 219 void 220 cnremove(struct consdev *cn) 221 { 222 struct cn_device *cnd; 223 224 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) { 225 if (cnd->cnd_cn != cn) 226 continue; 227 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next); 228 if (cnd->cnd_vp != NULL) 229 vn_close(cnd->cnd_vp, openflag, NOCRED, NULL); 230 cnd->cnd_vp = NULL; 231 cnd->cnd_cn = NULL; 232 #if 0 233 /* 234 * XXX 235 * syscons gets really confused if console resources are 236 * freed after the system has initialized. 237 */ 238 if (cn->cn_term != NULL) 239 cn->cn_term(cn); 240 #endif 241 return; 242 } 243 } 244 245 void 246 cnselect(struct consdev *cn) 247 { 248 struct cn_device *cnd; 249 250 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) { 251 if (cnd->cnd_cn != cn) 252 continue; 253 if (cnd == STAILQ_FIRST(&cn_devlist)) 254 return; 255 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next); 256 STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next); 257 return; 258 } 259 } 260 261 void 262 cndebug(char *str) 263 { 264 int i, len; 265 266 len = strlen(str); 267 cnputc('>'); cnputc('>'); cnputc('>'); cnputc(' '); 268 for (i = 0; i < len; i++) 269 cnputc(str[i]); 270 cnputc('\n'); 271 } 272 273 /* 274 * XXX: rewrite to use sbufs instead 275 */ 276 277 static int 278 sysctl_kern_console(SYSCTL_HANDLER_ARGS) 279 { 280 struct cn_device *cnd; 281 struct consdev *cp, **list; 282 char *name, *p; 283 int delete, len, error; 284 285 len = 2; 286 SET_FOREACH(list, cons_set) { 287 cp = *list; 288 if (cp->cn_name[0] != '\0') 289 len += strlen(cp->cn_name) + 1; 290 } 291 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) 292 len += strlen(cnd->cnd_cn->cn_name) + 1; 293 len = len > CNDEVPATHMAX ? len : CNDEVPATHMAX; 294 MALLOC(name, char *, len, M_TEMP, M_WAITOK | M_ZERO); 295 p = name; 296 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) 297 p += sprintf(p, "%s,", cnd->cnd_cn->cn_name); 298 *p++ = '/'; 299 SET_FOREACH(list, cons_set) { 300 cp = *list; 301 if (cp->cn_name[0] != '\0') 302 p += sprintf(p, "%s,", cp->cn_name); 303 } 304 error = sysctl_handle_string(oidp, name, len, req); 305 if (error == 0 && req->newptr != NULL) { 306 p = name; 307 error = ENXIO; 308 delete = 0; 309 if (*p == '-') { 310 delete = 1; 311 p++; 312 } 313 SET_FOREACH(list, cons_set) { 314 cp = *list; 315 if (strcmp(p, cp->cn_name) != 0) 316 continue; 317 if (delete) { 318 cnremove(cp); 319 error = 0; 320 } else { 321 error = cnadd(cp); 322 if (error == 0) 323 cnselect(cp); 324 } 325 break; 326 } 327 } 328 FREE(name, M_TEMP); 329 return (error); 330 } 331 332 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW, 333 0, 0, sysctl_kern_console, "A", "Console device control"); 334 335 /* 336 * User has changed the state of the console muting. 337 * This may require us to open or close the device in question. 338 */ 339 static int 340 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS) 341 { 342 int error; 343 int ocn_mute; 344 345 ocn_mute = cn_mute; 346 error = sysctl_handle_int(oidp, &cn_mute, 0, req); 347 if (error != 0 || req->newptr == NULL) 348 return (error); 349 if (ocn_mute && !cn_mute && cn_is_open) 350 error = cnopen(NODEV, openflag, 0, curthread); 351 else if (!ocn_mute && cn_mute && cn_is_open) { 352 error = cnclose(NODEV, openflag, 0, curthread); 353 cn_is_open = 1; /* XXX hack */ 354 } 355 return (error); 356 } 357 358 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW, 359 0, sizeof(cn_mute), sysctl_kern_consmute, "I", ""); 360 361 static int 362 cn_devopen(struct cn_device *cnd, struct thread *td, int forceopen) 363 { 364 char path[CNDEVPATHMAX]; 365 struct nameidata nd; 366 struct vnode *vp; 367 dev_t dev; 368 int error; 369 370 if ((vp = cnd->cnd_vp) != NULL) { 371 if (!forceopen && vp->v_type != VBAD) { 372 dev = vp->v_rdev; 373 return ((*devsw(dev)->d_open)(dev, openflag, 0, td)); 374 } 375 cnd->cnd_vp = NULL; 376 vn_close(vp, openflag, td->td_ucred, td); 377 } 378 snprintf(path, sizeof(path), "/dev/%s", cnd->cnd_cn->cn_name); 379 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path, td); 380 error = vn_open(&nd, &openflag, 0, -1); 381 if (error == 0) { 382 NDFREE(&nd, NDF_ONLY_PNBUF); 383 VOP_UNLOCK(nd.ni_vp, 0, td); 384 if (nd.ni_vp->v_type == VCHR) 385 cnd->cnd_vp = nd.ni_vp; 386 else 387 vn_close(nd.ni_vp, openflag, td->td_ucred, td); 388 } 389 return (cnd->cnd_vp != NULL); 390 } 391 392 static int 393 cnopen(dev_t dev, int flag, int mode, struct thread *td) 394 { 395 struct cn_device *cnd; 396 397 openflag = flag | FWRITE; /* XXX */ 398 cn_is_open = 1; /* console is logically open */ 399 if (cn_mute) 400 return (0); 401 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) 402 cn_devopen(cnd, td, 0); 403 return (0); 404 } 405 406 static int 407 cnclose(dev_t dev, int flag, int mode, struct thread *td) 408 { 409 struct cn_device *cnd; 410 struct vnode *vp; 411 412 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) { 413 if ((vp = cnd->cnd_vp) == NULL) 414 continue; 415 cnd->cnd_vp = NULL; 416 vn_close(vp, openflag, td->td_ucred, td); 417 } 418 cn_is_open = 0; 419 return (0); 420 } 421 422 static int 423 cnread(dev_t dev, struct uio *uio, int flag) 424 { 425 struct cn_device *cnd; 426 427 cnd = STAILQ_FIRST(&cn_devlist); 428 if (cn_mute || CND_INVALID(cnd, curthread)) 429 return (0); 430 dev = cnd->cnd_vp->v_rdev; 431 return ((*devsw(dev)->d_read)(dev, uio, flag)); 432 } 433 434 static int 435 cnwrite(dev_t dev, struct uio *uio, int flag) 436 { 437 struct cn_device *cnd; 438 439 cnd = STAILQ_FIRST(&cn_devlist); 440 if (cn_mute || CND_INVALID(cnd, curthread)) 441 goto done; 442 if (constty) 443 dev = constty->t_dev; 444 else 445 dev = cnd->cnd_vp->v_rdev; 446 if (dev != NULL) { 447 log_console(uio); 448 return ((*devsw(dev)->d_write)(dev, uio, flag)); 449 } 450 done: 451 uio->uio_resid = 0; /* dump the data */ 452 return (0); 453 } 454 455 static int 456 cnioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td) 457 { 458 struct cn_device *cnd; 459 int error; 460 461 cnd = STAILQ_FIRST(&cn_devlist); 462 if (cn_mute || CND_INVALID(cnd, td)) 463 return (0); 464 /* 465 * Superuser can always use this to wrest control of console 466 * output from the "virtual" console. 467 */ 468 if (cmd == TIOCCONS && constty) { 469 error = suser(td); 470 if (error) 471 return (error); 472 constty = NULL; 473 return (0); 474 } 475 dev = cnd->cnd_vp->v_rdev; 476 if (dev != NULL) 477 return ((*devsw(dev)->d_ioctl)(dev, cmd, data, flag, td)); 478 return (0); 479 } 480 481 /* 482 * XXX 483 * poll/kqfilter do not appear to be correct 484 */ 485 static int 486 cnpoll(dev_t dev, int events, struct thread *td) 487 { 488 struct cn_device *cnd; 489 490 cnd = STAILQ_FIRST(&cn_devlist); 491 if (cn_mute || CND_INVALID(cnd, td)) 492 return (0); 493 dev = cnd->cnd_vp->v_rdev; 494 if (dev != NULL) 495 return ((*devsw(dev)->d_poll)(dev, events, td)); 496 return (0); 497 } 498 499 static int 500 cnkqfilter(dev_t dev, struct knote *kn) 501 { 502 struct cn_device *cnd; 503 504 cnd = STAILQ_FIRST(&cn_devlist); 505 if (cn_mute || CND_INVALID(cnd, curthread)) 506 return (1); 507 dev = cnd->cnd_vp->v_rdev; 508 if (dev != NULL) 509 return ((*devsw(dev)->d_kqfilter)(dev, kn)); 510 return (1); 511 } 512 513 /* 514 * Low level console routines. 515 */ 516 int 517 cngetc(void) 518 { 519 int c; 520 521 if (cn_mute) 522 return (-1); 523 while ((c = cncheckc()) == -1) 524 ; 525 if (c == '\r') 526 c = '\n'; /* console input is always ICRNL */ 527 return (c); 528 } 529 530 int 531 cncheckc(void) 532 { 533 struct cn_device *cnd; 534 struct consdev *cn; 535 int c; 536 537 if (cn_mute) 538 return (-1); 539 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) { 540 cn = cnd->cnd_cn; 541 #ifdef DDB 542 if (!db_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) { 543 #endif 544 c = cn->cn_checkc(cn); 545 if (c != -1) { 546 return (c); 547 } 548 #ifdef DDB 549 } 550 #endif 551 } 552 return (-1); 553 } 554 555 void 556 cnputc(int c) 557 { 558 struct cn_device *cnd; 559 struct consdev *cn; 560 char *cp; 561 562 if (cn_mute || c == '\0') 563 return; 564 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) { 565 cn = cnd->cnd_cn; 566 #ifdef DDB 567 if (!db_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) { 568 #endif 569 if (c == '\n') 570 cn->cn_putc(cn, '\r'); 571 cn->cn_putc(cn, c); 572 #ifdef DDB 573 } 574 #endif 575 } 576 #ifdef DDB 577 if (console_pausing && !db_active && (c == '\n')) { 578 #else 579 if (console_pausing && (c == '\n')) { 580 #endif 581 for (cp = console_pausestr; *cp != '\0'; cp++) 582 cnputc(*cp); 583 if (cngetc() == '.') 584 console_pausing = 0; 585 cnputc('\r'); 586 for (cp = console_pausestr; *cp != '\0'; cp++) 587 cnputc(' '); 588 cnputc('\r'); 589 } 590 } 591 592 void 593 cndbctl(int on) 594 { 595 struct cn_device *cnd; 596 struct consdev *cn; 597 static int refcount; 598 599 if (!on) 600 refcount--; 601 if (refcount == 0) 602 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) { 603 cn = cnd->cnd_cn; 604 if (cn->cn_dbctl != NULL) 605 cn->cn_dbctl(cn, on); 606 } 607 if (on) 608 refcount++; 609 } 610 611 static int consmsgbuf_size = 8192; 612 SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0, 613 ""); 614 615 /* 616 * Redirect console output to a tty. 617 */ 618 void 619 constty_set(struct tty *tp) 620 { 621 int size; 622 623 KASSERT(tp != NULL, ("constty_set: NULL tp")); 624 if (consbuf == NULL) { 625 size = consmsgbuf_size; 626 consbuf = malloc(size, M_TTYS, M_WAITOK); 627 msgbuf_init(&consmsgbuf, consbuf, size); 628 callout_init(&conscallout, 0); 629 } 630 constty = tp; 631 constty_timeout(NULL); 632 } 633 634 /* 635 * Disable console redirection to a tty. 636 */ 637 void 638 constty_clear(void) 639 { 640 int c; 641 642 constty = NULL; 643 if (consbuf == NULL) 644 return; 645 callout_stop(&conscallout); 646 while ((c = msgbuf_getchar(&consmsgbuf)) != -1) 647 cnputc(c); 648 free(consbuf, M_TTYS); 649 consbuf = NULL; 650 } 651 652 /* Times per second to check for pending console tty messages. */ 653 static int constty_wakeups_per_second = 5; 654 SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW, 655 &constty_wakeups_per_second, 0, ""); 656 657 static void 658 constty_timeout(void *arg) 659 { 660 int c; 661 662 while (constty != NULL && (c = msgbuf_getchar(&consmsgbuf)) != -1) { 663 if (tputchar(c, constty) < 0) 664 constty = NULL; 665 } 666 if (constty != NULL) { 667 callout_reset(&conscallout, hz / constty_wakeups_per_second, 668 constty_timeout, NULL); 669 } else { 670 /* Deallocate the constty buffer memory. */ 671 constty_clear(); 672 } 673 } 674 675 static void 676 cn_drvinit(void *unused) 677 { 678 679 make_dev(&cn_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "console"); 680 } 681 682 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL)
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