sys/kern/tty_cons.c

   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  * $FreeBSD: src/sys/kern/tty_cons.c,v 1.81.2.4 2001/12/17 18:44:41 guido Exp $
  40  * $DragonFly: src/sys/kern/tty_cons.c,v 1.21 2007/05/07 05:21:41 dillon Exp $
  41  */
  42
  43 #include "opt_ddb.h"
  44
  45 #include <sys/param.h>
  46 #include <sys/systm.h>
  47 #include <sys/conf.h>
  48 #include <sys/cons.h>
  49 #include <sys/kernel.h>
  50 #include <sys/proc.h>
  51 #include <sys/priv.h>
  52 #include <sys/reboot.h>
  53 #include <sys/sysctl.h>
  54 #include <sys/tty.h>
  55 #include <sys/uio.h>
  56 #include <sys/msgport.h>
  57 #include <sys/msgport2.h>
  58 #include <sys/device.h>
  59
  60 #include <ddb/ddb.h>
  61
  62 #include <machine/cpu.h>
  63
  64 static d_open_t cnopen;
  65 static d_close_t cnclose;
  66 static d_read_t cnread;
  67 static d_write_t cnwrite;
  68 static d_ioctl_t cnioctl;
  69 static d_poll_t cnpoll;
  70 static d_kqfilter_t cnkqfilter;
  71
  72 static int cnintercept(struct dev_generic_args *ap);
  73
  74 #define CDEV_MAJOR      0
  75 static struct dev_ops cn_ops = {
  76         { "console", CDEV_MAJOR, D_TTY | D_KQFILTER },
  77         .d_open =       cnopen,
  78         .d_close =      cnclose,
  79         .d_read =       cnread,
  80         .d_write =      cnwrite,
  81         .d_ioctl =      cnioctl,
  82         .d_poll =       cnpoll,
  83         .d_kqfilter =   cnkqfilter,
  84 };
  85
  86 static struct dev_ops cn_iops = {
  87         { "intercept", CDEV_MAJOR, D_TTY | D_KQFILTER },
  88         .d_default =    cnintercept
  89 };
  90
  91 static struct dev_ops *cn_fwd_ops;
  92 static cdev_t   cn_dev;
  93 static udev_t   cn_udev;
  94 SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD,
  95         &cn_udev, sizeof cn_udev, "T,udev_t", "");
  96
  97 static int cn_mute;
  98
  99 int     cons_unavail = 0;       /* XXX:
 100                                  * physical console not available for
 101                                  * input (i.e., it is in graphics mode)
 102                                  */
 103
 104 static u_char cn_is_open;               /* nonzero if logical console is open */
 105 static int openmode, openflag;          /* how /dev/console was openned */
 106 static cdev_t cn_devfsdev;              /* represents the device private info */
 107 static u_char cn_phys_is_open;          /* nonzero if physical device is open */
 108 static u_char console_pausing;          /* pause after each line during probe */
 109 static char *console_pausestr=
 110 "<pause; press any key to proceed to next line or '.' to end pause mode>";
 111
 112 struct consdev *cn_tab;         /* physical console device info */
 113 struct consdev *gdb_tab;        /* physical gdb debugger device info */
 114
 115 CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
 116 SET_DECLARE(cons_set, struct consdev);
 117
 118 void
 119 cninit(void)
 120 {
 121         struct consdev *best_cp, *cp, **list;
 122
 123         /*
 124          * Find the first console with the highest priority.
 125          */
 126         best_cp = NULL;
 127         SET_FOREACH(list, cons_set) {
 128                 cp = *list;
 129                 if (cp->cn_probe == NULL)
 130                         continue;
 131                 (*cp->cn_probe)(cp);
 132                 if (cp->cn_pri > CN_DEAD && cp->cn_probegood &&
 133                     (best_cp == NULL || cp->cn_pri > best_cp->cn_pri))
 134                         best_cp = cp;
 135         }
 136
 137         /*
 138          * Check if we should mute the console (for security reasons perhaps)
 139          * It can be changes dynamically using sysctl kern.consmute
 140          * once we are up and going.
 141          *
 142          */
 143         cn_mute = ((boothowto & (RB_MUTE
 144                         |RB_SINGLE
 145                         |RB_VERBOSE
 146                         |RB_ASKNAME
 147                         |RB_CONFIG)) == RB_MUTE);
 148
 149         /*
 150          * If no console, give up.
 151          */
 152         if (best_cp == NULL) {
 153                 if (cn_tab != NULL && cn_tab->cn_term != NULL)
 154                         (*cn_tab->cn_term)(cn_tab);
 155                 cn_tab = best_cp;
 156                 return;
 157         }
 158
 159         /*
 160          * Initialize console, then attach to it.  This ordering allows
 161          * debugging using the previous console, if any.
 162          */
 163         (*best_cp->cn_init)(best_cp);
 164         if (cn_tab != NULL && cn_tab != best_cp) {
 165                 /* Turn off the previous console.  */
 166                 if (cn_tab->cn_term != NULL)
 167                         (*cn_tab->cn_term)(cn_tab);
 168         }
 169         if (boothowto & RB_PAUSE)
 170                 console_pausing = 1;
 171         cn_tab = best_cp;
 172 }
 173
 174 /*
 175  * Hook the open and close functions on the selected device.
 176  */
 177 void
 178 cninit_finish(void)
 179 {
 180         if ((cn_tab == NULL) || cn_mute)
 181                 return;
 182
 183         if (cn_tab->cn_dev == NULL) {
 184                 cn_tab->cn_init_fini(cn_tab);
 185         }
 186         if (cn_tab->cn_dev == NULL) {
 187                 kprintf("Unable to hook console open and close! cn_tab %p\n",
 188                         cn_tab);
 189                 return;
 190         }
 191
 192         /*
 193          * Hook the open and close functions.  XXX bad hack.
 194          */
 195         if (dev_is_good(cn_tab->cn_dev)) {
 196                 cn_fwd_ops = dev_ops_intercept(cn_tab->cn_dev, &cn_iops);
 197         }
 198         cn_dev = cn_tab->cn_dev;
 199         cn_udev = dev2udev(cn_dev);
 200         console_pausing = 0;
 201 }
 202
 203 static void
 204 cnuninit(void)
 205 {
 206         if (cn_tab == NULL)
 207                 return;
 208
 209         /*
 210          * Unhook the open and close functions.  XXX bad hack
 211          */
 212         if (cn_fwd_ops)
 213                 dev_ops_restore(cn_tab->cn_dev, cn_fwd_ops);
 214         cn_fwd_ops = NULL;
 215         cn_dev = NULL;
 216         cn_udev = NOUDEV;
 217 }
 218
 219 /*
 220  * User has changed the state of the console muting.
 221  * This may require us to open or close the device in question.
 222  */
 223 static int
 224 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
 225 {
 226         int error;
 227         int ocn_mute;
 228
 229         ocn_mute = cn_mute;
 230         error = sysctl_handle_int(oidp, &cn_mute, 0, req);
 231         if((error == 0) && (cn_tab != NULL) && (req->newptr != NULL)) {
 232                 if(ocn_mute && !cn_mute) {
 233                         /*
 234                          * going from muted to unmuted.. open the physical dev
 235                          * if the console has been openned
 236                          */
 237                         cninit_finish();
 238                         if (cn_is_open) {
 239                                 /* XXX curproc is not what we want really */
 240                                 error = dev_dopen(cn_dev, openflag,
 241                                                 openmode, curproc->p_ucred);
 242                         }
 243                         /* if it failed, back it out */
 244                         if ( error != 0) cnuninit();
 245                 } else if (!ocn_mute && cn_mute) {
 246                         /*
 247                          * going from unmuted to muted.. close the physical dev
 248                          * if it's only open via /dev/console
 249                          */
 250                         if (cn_is_open) {
 251                                 error = dev_dclose(cn_dev, openflag,
 252                                                 openmode);
 253                         }
 254                         if (error == 0)
 255                                 cnuninit();
 256                 }
 257                 if (error != 0) {
 258                         /*
 259                          * back out the change if there was an error
 260                          */
 261                         cn_mute = ocn_mute;
 262                 }
 263         }
 264         return (error);
 265 }
 266
 267 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
 268         0, sizeof cn_mute, sysctl_kern_consmute, "I", "");
 269
 270 /*
 271  * We intercept the OPEN and CLOSE calls on the original device, and
 272  * forward the rest through.
 273  */
 274 static int
 275 cnintercept(struct dev_generic_args *ap)
 276 {
 277         int error;
 278
 279         if (ap->a_desc == &dev_open_desc) {
 280                 error = cnopen((struct dev_open_args *)ap);
 281         } else if (ap->a_desc == &dev_close_desc) {
 282                 error = cnclose((struct dev_close_args *)ap);
 283         } else if (cn_fwd_ops) {
 284                 error = dev_doperate_ops(cn_fwd_ops, ap);
 285         } else {
 286                 error = ENXIO;
 287         }
 288         return (error);
 289 }
 290
 291 /*
 292  * cnopen() is called as an intercept function (dev will be that of the
 293  * actual physical device representing our console), and also called from
 294  * the muting code and from the /dev/console switch (dev will have the
 295  * console's cdevsw).
 296  */
 297 static int
 298 cnopen(struct dev_open_args *ap)
 299 {
 300         cdev_t dev = ap->a_head.a_dev;
 301         int flag = ap->a_oflags;
 302         int mode = ap->a_devtype;
 303         cdev_t cndev, physdev;
 304         int retval = 0;
 305
 306         if (cn_tab == NULL || cn_fwd_ops == NULL)
 307                 return (0);
 308         cndev = cn_tab->cn_dev;
 309         physdev = (major(dev) == major(cndev) ? dev : cndev);
 310
 311         /*
 312          * If mute is active, then non console opens don't get here
 313          * so we don't need to check for that. They bypass this and go
 314          * straight to the device.
 315          *
 316          * It is important to note that due to our intercept and the fact
 317          * that we might be called via the original (intercepted) device,
 318          * the original device's ops may point to us, so to avoid an
 319          * infinite recursion we have to forward through cn_fwd_ops.
 320          * This is a severe hack that really needs to be fixed XXX.
 321          *
 322          * XXX at the moment we assume that the port forwarding function
 323          * is synchronous for open.
 324          */
 325         if (!cn_mute) {
 326                 ap->a_head.a_dev = physdev;
 327                 retval = dev_doperate_ops(cn_fwd_ops, &ap->a_head);
 328         }
 329         if (retval == 0) {
 330                 /*
 331                  * check if we openned it via /dev/console or
 332                  * via the physical entry (e.g. /dev/sio0).
 333                  */
 334                 if (dev == cndev)
 335                         cn_phys_is_open = 1;
 336                 else if (physdev == cndev) {
 337                         openmode = mode;
 338                         openflag = flag;
 339                         cn_is_open = 1;
 340                 }
 341                 dev->si_tty = physdev->si_tty;
 342         }
 343         return (retval);
 344 }
 345
 346 /*
 347  * cnclose() is called as a port intercept function (dev will be that of the
 348  * actual physical device representing our console), and also called from
 349  * the muting code and from the /dev/console switch (dev will have the
 350  * console's cdevsw).
 351  */
 352 static int
 353 cnclose(struct dev_close_args *ap)
 354 {
 355         cdev_t dev = ap->a_head.a_dev;
 356         cdev_t cndev;
 357         struct tty *cn_tp;
 358
 359         if (cn_tab == NULL || cn_fwd_ops == NULL)
 360                 return (0);
 361         cndev = cn_tab->cn_dev;
 362         cn_tp = cndev->si_tty;
 363         /*
 364          * act appropriatly depending on whether it's /dev/console
 365          * or the pysical device (e.g. /dev/sio) that's being closed.
 366          * in either case, don't actually close the device unless
 367          * both are closed.
 368          */
 369         if (dev == cndev) {
 370                 /* the physical device is about to be closed */
 371                 cn_phys_is_open = 0;
 372                 if (cn_is_open) {
 373                         if (cn_tp) {
 374                                 /* perform a ttyhalfclose() */
 375                                 /* reset session and proc group */
 376                                 ttyclearsession(cn_tp);
 377                         }
 378                         return (0);
 379                 }
 380         } else if (major(dev) != major(cndev)) {
 381                 /* the logical console is about to be closed */
 382                 cn_is_open = 0;
 383                 if (cn_phys_is_open)
 384                         return (0);
 385                 dev = cndev;
 386         }
 387         if (cn_fwd_ops) {
 388                 ap->a_head.a_dev = dev;
 389                 return (dev_doperate_ops(cn_fwd_ops, &ap->a_head));
 390         }
 391         return (0);
 392 }
 393
 394 /*
 395  * The following functions are dispatched solely from the /dev/console
 396  * device.  Their job is primarily to forward the request through.
 397  * If the console is not attached to anything then write()'s are sunk
 398  * to null and reads return 0 (mostly).
 399  */
 400 static int
 401 cnread(struct dev_read_args *ap)
 402 {
 403         if (cn_tab == NULL || cn_fwd_ops == NULL)
 404                 return (0);
 405         ap->a_head.a_dev = cn_tab->cn_dev;
 406         return (dev_doperate(&ap->a_head));
 407 }
 408
 409 static int
 410 cnwrite(struct dev_write_args *ap)
 411 {
 412         struct uio *uio = ap->a_uio;
 413         cdev_t dev;
 414
 415         if (cn_tab == NULL || cn_fwd_ops == NULL) {
 416                 uio->uio_resid = 0; /* dump the data */
 417                 return (0);
 418         }
 419         if (constty)
 420                 dev = constty->t_dev;
 421         else
 422                 dev = cn_tab->cn_dev;
 423         log_console(uio);
 424         ap->a_head.a_dev = dev;
 425         return (dev_doperate(&ap->a_head));
 426 }
 427
 428 static int
 429 cnioctl(struct dev_ioctl_args *ap)
 430 {
 431         int error;
 432
 433         if (cn_tab == NULL || cn_fwd_ops == NULL)
 434                 return (0);
 435         KKASSERT(curproc != NULL);
 436         /*
 437          * Superuser can always use this to wrest control of console
 438          * output from the "virtual" console.
 439          */
 440         if (ap->a_cmd == TIOCCONS && constty) {
 441                 if (ap->a_cred) {
 442                         error = priv_check_cred(ap->a_cred, PRIV_ROOT, 0);
 443                         if (error)
 444                                 return (error);
 445                 }
 446                 constty = NULL;
 447                 return (0);
 448         }
 449         ap->a_head.a_dev = cn_tab->cn_dev;
 450         return (dev_doperate(&ap->a_head));
 451 }
 452
 453 static int
 454 cnpoll(struct dev_poll_args *ap)
 455 {
 456         if ((cn_tab == NULL) || cn_mute || cn_fwd_ops == NULL)
 457                 return (1);
 458         ap->a_head.a_dev = cn_tab->cn_dev;
 459         return (dev_doperate(&ap->a_head));
 460 }
 461
 462 static int
 463 cnkqfilter(struct dev_kqfilter_args *ap)
 464 {
 465         if ((cn_tab == NULL) || cn_mute || cn_fwd_ops == NULL)
 466                 return (1);
 467         ap->a_head.a_dev = cn_tab->cn_dev;
 468         return (dev_doperate(&ap->a_head));
 469 }
 470
 471 /*
 472  * These synchronous functions are primarily used the kernel needs to
 473  * access the keyboard (e.g. when running the debugger), or output data
 474  * directly to the console.
 475  */
 476 int
 477 cngetc(void)
 478 {
 479         int c;
 480         if ((cn_tab == NULL) || cn_mute)
 481                 return (-1);
 482         c = (*cn_tab->cn_getc)(cn_tab->cn_dev);
 483         if (c == '\r') c = '\n'; /* console input is always ICRNL */
 484         return (c);
 485 }
 486
 487 int
 488 cncheckc(void)
 489 {
 490         if ((cn_tab == NULL) || cn_mute)
 491                 return (-1);
 492         return ((*cn_tab->cn_checkc)(cn_tab->cn_dev));
 493 }
 494
 495 void
 496 cnputc(int c)
 497 {
 498         char *cp;
 499
 500         if ((cn_tab == NULL) || cn_mute)
 501                 return;
 502         if (c) {
 503                 if (c == '\n')
 504                         (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
 505                 (*cn_tab->cn_putc)(cn_tab->cn_dev, c);
 506 #ifdef DDB
 507                 if (console_pausing && !db_active && (c == '\n')) {
 508 #else
 509                 if (console_pausing && (c == '\n')) {
 510 #endif
 511                         for(cp=console_pausestr; *cp != '\0'; cp++)
 512                             (*cn_tab->cn_putc)(cn_tab->cn_dev, *cp);
 513                         if (cngetc() == '.')
 514                                 console_pausing = 0;
 515                         (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
 516                         for(cp=console_pausestr; *cp != '\0'; cp++)
 517                             (*cn_tab->cn_putc)(cn_tab->cn_dev, ' ');
 518                         (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
 519                 }
 520         }
 521 }
 522
 523 void
 524 cndbctl(int on)
 525 {
 526         static int refcount;
 527
 528         if (cn_tab == NULL)
 529                 return;
 530         if (!on)
 531                 refcount--;
 532         if (refcount == 0 && cn_tab->cn_dbctl != NULL)
 533                 (*cn_tab->cn_dbctl)(cn_tab->cn_dev, on);
 534         if (on)
 535                 refcount++;
 536 }
 537
 538 static void
 539 cn_drvinit(void *unused)
 540 {
 541         dev_ops_add(&cn_ops, 0, 0);
 542         cn_devfsdev = make_dev(&cn_ops, 0, UID_ROOT, GID_WHEEL,
 543                                 0600, "console");
 544 }
 545
 546 SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)