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  * $FreeBSD: releng/5.0/sys/kern/tty_cons.c 105354 2002-10-17 20:03:38Z robert $
   40  */
   41 
   42 #include "opt_ddb.h"
   43 
   44 #include <sys/param.h>
   45 #include <sys/systm.h>
   46 #include <sys/conf.h>
   47 #include <sys/cons.h>
   48 #include <sys/fcntl.h>
   49 #include <sys/kernel.h>
   50 #include <sys/malloc.h>
   51 #include <sys/namei.h>
   52 #include <sys/proc.h>
   53 #include <sys/queue.h>
   54 #include <sys/reboot.h>
   55 #include <sys/sysctl.h>
   56 #include <sys/tty.h>
   57 #include <sys/uio.h>
   58 #include <sys/vnode.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 #define CDEV_MAJOR      0
   73 static struct cdevsw cn_cdevsw = {
   74         /* open */      cnopen,
   75         /* close */     cnclose,
   76         /* read */      cnread,
   77         /* write */     cnwrite,
   78         /* ioctl */     cnioctl,
   79         /* poll */      cnpoll,
   80         /* mmap */      nommap,
   81         /* strategy */  nostrategy,
   82         /* name */      "console",
   83         /* maj */       CDEV_MAJOR,
   84         /* dump */      nodump,
   85         /* psize */     nopsize,
   86         /* flags */     D_TTY | D_KQFILTER,
   87         /* kqfilter */  cnkqfilter,
   88 };
   89 
   90 struct cn_device {
   91         STAILQ_ENTRY(cn_device) cnd_next;
   92         char            cnd_name[16];
   93         struct          vnode *cnd_vp;
   94         struct          consdev *cnd_cn;
   95 };
   96 
   97 #define CNDEVPATHMAX    32
   98 #define CNDEVTAB_SIZE   4
   99 static struct cn_device cn_devtab[CNDEVTAB_SIZE];
  100 static STAILQ_HEAD(, cn_device) cn_devlist =
  101     STAILQ_HEAD_INITIALIZER(cn_devlist);
  102 
  103 #define CND_INVALID(cnd, td)                                            \
  104         (cnd == NULL || cnd->cnd_vp == NULL ||                          \
  105             (cnd->cnd_vp->v_type == VBAD && !cn_devopen(cnd, td, 1)))
  106 
  107 static udev_t   cn_udev_t;
  108 SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD,
  109         &cn_udev_t, sizeof cn_udev_t, "T,dev_t", "");
  110 
  111 int     cons_unavail = 0;       /* XXX:
  112                                  * physical console not available for
  113                                  * input (i.e., it is in graphics mode)
  114                                  */
  115 static int cn_mute;
  116 static int openflag;                    /* how /dev/console was opened */
  117 static int cn_is_open;
  118 static dev_t cn_devfsdev;               /* represents the device private info */
  119 static u_char console_pausing;          /* pause after each line during probe */
  120 static char *console_pausestr=
  121 "<pause; press any key to proceed to next line or '.' to end pause mode>";
  122 
  123 void    cndebug(char *);
  124 
  125 CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
  126 SET_DECLARE(cons_set, struct consdev);
  127 
  128 void
  129 cninit(void)
  130 {
  131         struct consdev *best_cn, *cn, **list;
  132 
  133         /*
  134          * Check if we should mute the console (for security reasons perhaps)
  135          * It can be changes dynamically using sysctl kern.consmute
  136          * once we are up and going.
  137          * 
  138          */
  139         cn_mute = ((boothowto & (RB_MUTE
  140                         |RB_SINGLE
  141                         |RB_VERBOSE
  142                         |RB_ASKNAME
  143                         |RB_CONFIG)) == RB_MUTE);
  144 
  145         /*
  146          * Find the first console with the highest priority.
  147          */
  148         best_cn = NULL;
  149         SET_FOREACH(list, cons_set) {
  150                 cn = *list;
  151                 cnremove(cn);
  152                 if (cn->cn_probe == NULL)
  153                         continue;
  154                 cn->cn_probe(cn);
  155                 if (cn->cn_pri == CN_DEAD)
  156                         continue;
  157                 if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
  158                         best_cn = cn;
  159                 if (boothowto & RB_MULTIPLE) {
  160                         /*
  161                          * Initialize console, and attach to it.
  162                          */
  163                         cnadd(cn);
  164                         cn->cn_init(cn);
  165                 }
  166         }
  167         if (best_cn == NULL)
  168                 return;
  169         if ((boothowto & RB_MULTIPLE) == 0) {
  170                 cnadd(best_cn);
  171                 best_cn->cn_init(best_cn);
  172         }
  173         if (boothowto & RB_PAUSE)
  174                 console_pausing = 1;
  175         /*
  176          * Make the best console the preferred console.
  177          */
  178         cnselect(best_cn);
  179 }
  180 
  181 void
  182 cninit_finish()
  183 {
  184         console_pausing = 0;
  185 } 
  186 
  187 /* add a new physical console to back the virtual console */
  188 int
  189 cnadd(struct consdev *cn)
  190 {
  191         struct cn_device *cnd;
  192         int i;
  193 
  194         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
  195                 if (cnd->cnd_cn == cn)
  196                         return (0);
  197         for (i = 0; i < CNDEVTAB_SIZE; i++) {
  198                 cnd = &cn_devtab[i];
  199                 if (cnd->cnd_cn == NULL)
  200                         break;
  201         }
  202         if (cnd->cnd_cn != NULL)
  203                 return (ENOMEM);
  204         cnd->cnd_cn = cn;
  205         STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
  206         return (0);
  207 }
  208 
  209 void
  210 cnremove(struct consdev *cn)
  211 {
  212         struct cn_device *cnd;
  213 
  214         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
  215                 if (cnd->cnd_cn != cn)
  216                         continue;
  217                 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
  218                 if (cnd->cnd_vp != NULL)
  219                         vn_close(cnd->cnd_vp, openflag, NOCRED, NULL);
  220                 cnd->cnd_vp = NULL;
  221                 cnd->cnd_cn = NULL;
  222                 cnd->cnd_name[0] = '\0';
  223 #if 0
  224                 /*
  225                  * XXX
  226                  * syscons gets really confused if console resources are
  227                  * freed after the system has initialized.
  228                  */
  229                 if (cn->cn_term != NULL)
  230                         cn->cn_term(cn);
  231 #endif
  232                 return;
  233         }
  234 }
  235 
  236 void
  237 cnselect(struct consdev *cn)
  238 {
  239         struct cn_device *cnd;
  240 
  241         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
  242                 if (cnd->cnd_cn != cn)
  243                         continue;
  244                 if (cnd == STAILQ_FIRST(&cn_devlist))
  245                         return;
  246                 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
  247                 STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
  248                 return;
  249         }
  250 }
  251 
  252 void
  253 cndebug(char *str)
  254 {
  255         int i, len;
  256 
  257         len = strlen(str);
  258         cnputc('>'); cnputc('>'); cnputc('>'); cnputc(' '); 
  259         for (i = 0; i < len; i++)
  260                 cnputc(str[i]);
  261         cnputc('\n');
  262 }
  263 
  264 static int
  265 sysctl_kern_console(SYSCTL_HANDLER_ARGS)
  266 {
  267         struct cn_device *cnd;
  268         struct consdev *cp, **list;
  269         char *name, *p;
  270         int delete, len, error;
  271 
  272         len = 2;
  273         SET_FOREACH(list, cons_set) {
  274                 cp = *list;
  275                 if (cp->cn_dev != NULL)
  276                         len += strlen(devtoname(cp->cn_dev)) + 1;
  277         }
  278         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
  279                 len += strlen(devtoname(cnd->cnd_cn->cn_dev)) + 1;
  280         len = len > CNDEVPATHMAX ? len : CNDEVPATHMAX;
  281         MALLOC(name, char *, len, M_TEMP, M_WAITOK | M_ZERO);
  282         p = name;
  283         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
  284                 p += sprintf(p, "%s,", devtoname(cnd->cnd_cn->cn_dev));
  285         *p++ = '/';
  286         SET_FOREACH(list, cons_set) {
  287                 cp = *list;
  288                 if (cp->cn_dev != NULL)
  289                         p += sprintf(p, "%s,", devtoname(cp->cn_dev));
  290         }
  291         error = sysctl_handle_string(oidp, name, len, req);
  292         if (error == 0 && req->newptr != NULL) {
  293                 p = name;
  294                 error = ENXIO;
  295                 delete = 0;
  296                 if (*p == '-') {
  297                         delete = 1;
  298                         p++;
  299                 }
  300                 SET_FOREACH(list, cons_set) {
  301                         cp = *list;
  302                         if (cp->cn_dev == NULL ||
  303                             strcmp(p, devtoname(cp->cn_dev)) != 0)
  304                                 continue;
  305                         if (delete) {
  306                                 cnremove(cp);
  307                                 error = 0;
  308                         } else {
  309                                 error = cnadd(cp);
  310                                 if (error == 0)
  311                                         cnselect(cp);
  312                         }
  313                         break;
  314                 }
  315         }
  316         FREE(name, M_TEMP);
  317         return (error);
  318 }
  319 
  320 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
  321         0, 0, sysctl_kern_console, "A", "Console device control");
  322 
  323 /*
  324  * User has changed the state of the console muting.
  325  * This may require us to open or close the device in question.
  326  */
  327 static int
  328 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
  329 {
  330         int error;
  331         int ocn_mute;
  332 
  333         ocn_mute = cn_mute;
  334         error = sysctl_handle_int(oidp, &cn_mute, 0, req);
  335         if (error != 0 || req->newptr == NULL)
  336                 return (error);
  337         if (ocn_mute && !cn_mute && cn_is_open)
  338                 error = cnopen(NODEV, openflag, 0, curthread);
  339         else if (!ocn_mute && cn_mute && cn_is_open) {
  340                 error = cnclose(NODEV, openflag, 0, curthread);
  341                 cn_is_open = 1;         /* XXX hack */
  342         }
  343         return (error);
  344 }
  345 
  346 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
  347         0, sizeof(cn_mute), sysctl_kern_consmute, "I", "");
  348 
  349 static int
  350 cn_devopen(struct cn_device *cnd, struct thread *td, int forceopen)
  351 {
  352         char path[CNDEVPATHMAX];
  353         struct nameidata nd;
  354         struct vnode *vp;
  355         dev_t dev;
  356         int error;
  357 
  358         if ((vp = cnd->cnd_vp) != NULL) {
  359                 if (!forceopen && vp->v_type != VBAD) {
  360                         dev = vp->v_rdev;
  361                         return ((*devsw(dev)->d_open)(dev, openflag, 0, td));
  362                 }
  363                 cnd->cnd_vp = NULL;
  364                 vn_close(vp, openflag, td->td_ucred, td);
  365         }
  366         if (cnd->cnd_name[0] == '\0') {
  367                 strlcpy(cnd->cnd_name, devtoname(cnd->cnd_cn->cn_dev),
  368                     sizeof(cnd->cnd_name));
  369         }
  370         snprintf(path, sizeof(path), "/dev/%s", cnd->cnd_name);
  371         NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path, td);
  372         error = vn_open(&nd, &openflag, 0);
  373         if (error == 0) {
  374                 NDFREE(&nd, NDF_ONLY_PNBUF);
  375                 VOP_UNLOCK(nd.ni_vp, 0, td);
  376                 if (nd.ni_vp->v_type == VCHR)
  377                         cnd->cnd_vp = nd.ni_vp;
  378                 else
  379                         vn_close(nd.ni_vp, openflag, td->td_ucred, td);
  380         }
  381         return (cnd->cnd_vp != NULL);
  382 }
  383 
  384 static int
  385 cnopen(dev_t dev, int flag, int mode, struct thread *td)
  386 {
  387         struct cn_device *cnd;
  388 
  389         openflag = flag | FWRITE;       /* XXX */
  390         cn_is_open = 1;                 /* console is logically open */
  391         if (cn_mute)
  392                 return (0);
  393         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
  394                 cn_devopen(cnd, td, 0);
  395         return (0);
  396 }
  397 
  398 static int
  399 cnclose(dev_t dev, int flag, int mode, struct thread *td)
  400 {
  401         struct cn_device *cnd;
  402         struct vnode *vp;
  403 
  404         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
  405                 if ((vp = cnd->cnd_vp) == NULL)
  406                         continue; 
  407                 cnd->cnd_vp = NULL;
  408                 vn_close(vp, openflag, td->td_ucred, td);
  409         }
  410         cn_is_open = 0;
  411         return (0);
  412 }
  413 
  414 static int
  415 cnread(dev_t dev, struct uio *uio, int flag)
  416 {
  417         struct cn_device *cnd;
  418 
  419         cnd = STAILQ_FIRST(&cn_devlist);
  420         if (cn_mute || CND_INVALID(cnd, curthread))
  421                 return (0);
  422         dev = cnd->cnd_vp->v_rdev;
  423         return ((*devsw(dev)->d_read)(dev, uio, flag));
  424 }
  425 
  426 static int
  427 cnwrite(dev_t dev, struct uio *uio, int flag)
  428 {
  429         struct cn_device *cnd;
  430 
  431         cnd = STAILQ_FIRST(&cn_devlist);
  432         if (cn_mute || CND_INVALID(cnd, curthread))
  433                 goto done;
  434         if (constty)
  435                 dev = constty->t_dev;
  436         else
  437                 dev = cnd->cnd_vp->v_rdev;
  438         if (dev != NULL) {
  439                 log_console(uio);
  440                 return ((*devsw(dev)->d_write)(dev, uio, flag));
  441         }
  442 done:
  443         uio->uio_resid = 0; /* dump the data */
  444         return (0);
  445 }
  446 
  447 static int
  448 cnioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
  449 {
  450         struct cn_device *cnd;
  451         int error;
  452 
  453         cnd = STAILQ_FIRST(&cn_devlist);
  454         if (cn_mute || CND_INVALID(cnd, td))
  455                 return (0);
  456         /*
  457          * Superuser can always use this to wrest control of console
  458          * output from the "virtual" console.
  459          */
  460         if (cmd == TIOCCONS && constty) {
  461                 error = suser(td);
  462                 if (error)
  463                         return (error);
  464                 constty = NULL;
  465                 return (0);
  466         }
  467         dev = cnd->cnd_vp->v_rdev;
  468         if (dev != NULL)
  469                 return ((*devsw(dev)->d_ioctl)(dev, cmd, data, flag, td));
  470         return (0);
  471 }
  472 
  473 /*
  474  * XXX
  475  * poll/kqfilter do not appear to be correct
  476  */
  477 static int
  478 cnpoll(dev_t dev, int events, struct thread *td)
  479 {
  480         struct cn_device *cnd;
  481 
  482         cnd = STAILQ_FIRST(&cn_devlist);
  483         if (cn_mute || CND_INVALID(cnd, td))
  484                 return (0);
  485         dev = cnd->cnd_vp->v_rdev;
  486         if (dev != NULL)
  487                 return ((*devsw(dev)->d_poll)(dev, events, td));
  488         return (0);
  489 }
  490 
  491 static int
  492 cnkqfilter(dev_t dev, struct knote *kn)
  493 {
  494         struct cn_device *cnd;
  495 
  496         cnd = STAILQ_FIRST(&cn_devlist);
  497         if (cn_mute || CND_INVALID(cnd, curthread))
  498                 return (1);
  499         dev = cnd->cnd_vp->v_rdev;
  500         if (dev != NULL)
  501                 return ((*devsw(dev)->d_kqfilter)(dev, kn));
  502         return (1);
  503 }
  504 
  505 /*
  506  * Low level console routines.
  507  */
  508 int
  509 cngetc(void)
  510 {
  511         int c;
  512 
  513         if (cn_mute)
  514                 return (-1);
  515         while ((c = cncheckc()) == -1)
  516                 ;
  517         if (c == '\r')
  518                 c = '\n';               /* console input is always ICRNL */
  519         return (c);
  520 }
  521 
  522 int
  523 cncheckc(void)
  524 {
  525         struct cn_device *cnd;
  526         struct consdev *cn;
  527         int c;
  528 
  529         if (cn_mute)
  530                 return (-1);
  531         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
  532                 cn = cnd->cnd_cn;
  533                 c = cn->cn_checkc(cn->cn_dev);
  534                 if (c != -1) {
  535                         return (c);
  536                 }
  537         }
  538         return (-1);
  539 }
  540 
  541 void
  542 cnputc(int c)
  543 {
  544         struct cn_device *cnd;
  545         struct consdev *cn;
  546         char *cp;
  547 
  548         if (cn_mute || c == '\0')
  549                 return;
  550         STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
  551                 cn = cnd->cnd_cn;
  552                 if (c == '\n')
  553                         cn->cn_putc(cn->cn_dev, '\r');
  554                 cn->cn_putc(cn->cn_dev, c);
  555         }
  556 #ifdef DDB
  557         if (console_pausing && !db_active && (c == '\n')) {
  558 #else
  559         if (console_pausing && (c == '\n')) {
  560 #endif
  561                 for (cp = console_pausestr; *cp != '\0'; cp++)
  562                         cnputc(*cp);
  563                 if (cngetc() == '.')
  564                         console_pausing = 0;
  565                 cnputc('\r');
  566                 for (cp = console_pausestr; *cp != '\0'; cp++)
  567                         cnputc(' ');
  568                 cnputc('\r');
  569         }
  570 }
  571 
  572 void
  573 cndbctl(int on)
  574 {
  575         struct cn_device *cnd;
  576         struct consdev *cn;
  577         static int refcount;
  578 
  579         if (!on)
  580                 refcount--;
  581         if (refcount == 0)
  582                 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
  583                         cn = cnd->cnd_cn;
  584                         if (cn->cn_dbctl != NULL)
  585                                 cn->cn_dbctl(cn->cn_dev, on);
  586                 }
  587         if (on)
  588                 refcount++;
  589 }
  590 
  591 static void
  592 cn_drvinit(void *unused)
  593 {
  594 
  595         cn_devfsdev = make_dev(&cn_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
  596             "console");
  597 }
  598 
  599 SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)

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