kern_conf.c

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    1 /*-
    2  * Copyright (c) 1999-2002 Poul-Henning Kamp
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  *
   26  * $FreeBSD: releng/5.0/sys/kern/kern_conf.c 104523 2002-10-05 17:10:28Z green $
   27  */
   28 
   29 #include <sys/param.h>
   30 #include <sys/kernel.h>
   31 #include <sys/systm.h>
   32 #include <sys/lock.h>
   33 #include <sys/mutex.h>
   34 #include <sys/sysctl.h>
   35 #include <sys/module.h>
   36 #include <sys/malloc.h>
   37 #include <sys/conf.h>
   38 #include <sys/vnode.h>
   39 #include <sys/queue.h>
   40 #include <sys/ctype.h>
   41 #include <machine/stdarg.h>
   42 
   43 #define cdevsw_ALLOCSTART       (NUMCDEVSW/2)
   44 
   45 static struct cdevsw    *cdevsw[NUMCDEVSW];
   46 
   47 static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
   48 
   49 /*
   50  * This is the number of hash-buckets.  Experiements with 'real-life'
   51  * udev_t's show that a prime halfway between two powers of two works
   52  * best.
   53  */
   54 #define DEVT_HASH 83
   55 
   56 /* The number of dev_t's we can create before malloc(9) kick in.  */
   57 #define DEVT_STASH 50
   58 
   59 static struct cdev devt_stash[DEVT_STASH];
   60 
   61 static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
   62 
   63 static LIST_HEAD(, cdev) dev_free;
   64 
   65 devfs_create_t *devfs_create_hook;
   66 devfs_destroy_t *devfs_destroy_hook;
   67 int devfs_present;
   68 
   69 static int ready_for_devs;
   70 
   71 static int free_devt;
   72 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
   73 
   74 /* XXX: This is a hack */
   75 void disk_dev_synth(dev_t dev);
   76 
   77 struct cdevsw *
   78 devsw(dev_t dev)
   79 {
   80         if (dev->si_devsw)
   81                 return (dev->si_devsw);
   82         /* XXX: Hack around our backwards disk code */
   83         disk_dev_synth(dev);
   84         if (dev->si_devsw)
   85                 return (dev->si_devsw);
   86         if (devfs_present)
   87                 return (NULL);
   88         return(cdevsw[major(dev)]);
   89 }
   90 
   91 /*
   92  *  Add a cdevsw entry
   93  */
   94 
   95 int
   96 cdevsw_add(struct cdevsw *newentry)
   97 {
   98 
   99         if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
  100                 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
  101                     newentry->d_name, newentry->d_maj);
  102                 return (EINVAL);
  103         }
  104 
  105         if (cdevsw[newentry->d_maj]) {
  106                 printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
  107                     newentry->d_name, cdevsw[newentry->d_maj]->d_name);
  108         }
  109 
  110         cdevsw[newentry->d_maj] = newentry;
  111 
  112         return (0);
  113 }
  114 
  115 /*
  116  *  Remove a cdevsw entry
  117  */
  118 
  119 int
  120 cdevsw_remove(struct cdevsw *oldentry)
  121 {
  122         if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
  123                 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
  124                     oldentry->d_name, oldentry->d_maj);
  125                 return EINVAL;
  126         }
  127 
  128         cdevsw[oldentry->d_maj] = NULL;
  129 
  130         return 0;
  131 }
  132 
  133 /*
  134  * dev_t and u_dev_t primitives
  135  */
  136 
  137 int
  138 major(dev_t x)
  139 {
  140         if (x == NODEV)
  141                 return NOUDEV;
  142         return((x->si_udev >> 8) & 0xff);
  143 }
  144 
  145 int
  146 minor(dev_t x)
  147 {
  148         if (x == NODEV)
  149                 return NOUDEV;
  150         return(x->si_udev & 0xffff00ff);
  151 }
  152 
  153 int
  154 dev2unit(dev_t x)
  155 {
  156         int i;
  157 
  158         if (x == NODEV)
  159                 return NOUDEV;
  160         i = minor(x);
  161         return ((i & 0xff) | (i >> 8));
  162 }
  163 
  164 int
  165 unit2minor(int unit)
  166 {
  167 
  168         KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
  169         return ((unit & 0xff) | ((unit << 8) & ~0xffff));
  170 }
  171 
  172 static dev_t
  173 allocdev(void)
  174 {
  175         static int stashed;
  176         struct cdev *si;
  177 
  178         if (LIST_FIRST(&dev_free)) {
  179                 si = LIST_FIRST(&dev_free);
  180                 LIST_REMOVE(si, si_hash);
  181         } else if (stashed >= DEVT_STASH) {
  182                 MALLOC(si, struct cdev *, sizeof(*si), M_DEVT,
  183                     M_USE_RESERVE | M_ZERO);
  184         } else {
  185                 si = devt_stash + stashed++;
  186                 bzero(si, sizeof *si);
  187                 si->si_flags |= SI_STASHED;
  188         }
  189         LIST_INIT(&si->si_children);
  190         TAILQ_INIT(&si->si_snapshots);
  191         return (si);
  192 }
  193 
  194 dev_t
  195 makedev(int x, int y)
  196 {
  197         struct cdev *si;
  198         udev_t  udev;
  199         int hash;
  200 
  201         if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
  202                 panic("makedev of NOUDEV");
  203         udev = (x << 8) | y;
  204         hash = udev % DEVT_HASH;
  205         LIST_FOREACH(si, &dev_hash[hash], si_hash) {
  206                 if (si->si_udev == udev)
  207                         return (si);
  208         }
  209         si = allocdev();
  210         si->si_udev = udev;
  211         LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
  212         return (si);
  213 }
  214 
  215 void
  216 freedev(dev_t dev)
  217 {
  218 
  219         if (!free_devt)
  220                 return;
  221         if (SLIST_FIRST(&dev->si_hlist))
  222                 return;
  223         if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
  224                 return;
  225         LIST_REMOVE(dev, si_hash);
  226         if (dev->si_flags & SI_STASHED) {
  227                 bzero(dev, sizeof(*dev));
  228                 dev->si_flags |= SI_STASHED;
  229                 LIST_INSERT_HEAD(&dev_free, dev, si_hash);
  230         } else {
  231                 FREE(dev, M_DEVT);
  232         }
  233 }
  234 
  235 udev_t
  236 dev2udev(dev_t x)
  237 {
  238         if (x == NODEV)
  239                 return NOUDEV;
  240         return (x->si_udev);
  241 }
  242 
  243 dev_t
  244 udev2dev(udev_t x, int b)
  245 {
  246 
  247         if (x == NOUDEV)
  248                 return (NODEV);
  249         switch (b) {
  250                 case 0:
  251                         return makedev(umajor(x), uminor(x));
  252                 case 1:
  253                         return (NODEV);
  254                 default:
  255                         Debugger("udev2dev(...,X)");
  256                         return NODEV;
  257         }
  258 }
  259 
  260 int
  261 uminor(udev_t dev)
  262 {
  263         return(dev & 0xffff00ff);
  264 }
  265 
  266 int
  267 umajor(udev_t dev)
  268 {
  269         return((dev & 0xff00) >> 8);
  270 }
  271 
  272 udev_t
  273 makeudev(int x, int y)
  274 {
  275         return ((x << 8) | y);
  276 }
  277 
  278 dev_t
  279 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
  280 {
  281         dev_t   dev;
  282         va_list ap;
  283         int i;
  284 
  285         KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj,
  286             ("Invalid minor (%d) in make_dev", minor));
  287 
  288         if (!ready_for_devs) {
  289                 printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n",
  290                        fmt);
  291                 /* XXX panic here once drivers are cleaned up */
  292         }
  293 
  294         dev = makedev(devsw->d_maj, minor);
  295         if (dev->si_flags & SI_NAMED) {
  296                 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
  297                     dev->si_name);
  298                 panic("don't do that");
  299                 return (dev);
  300         }
  301         va_start(ap, fmt);
  302         i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
  303         dev->si_name[i] = '\0';
  304         va_end(ap);
  305         dev->si_devsw = devsw;
  306         dev->si_uid = uid;
  307         dev->si_gid = gid;
  308         dev->si_mode = perms;
  309         dev->si_flags |= SI_NAMED;
  310 
  311         if (devfs_create_hook)
  312                 devfs_create_hook(dev);
  313         return (dev);
  314 }
  315 
  316 int
  317 dev_named(dev_t pdev, const char *name)
  318 {
  319         dev_t cdev;
  320 
  321         if (strcmp(devtoname(pdev), name) == 0)
  322                 return (1);
  323         LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
  324                 if (strcmp(devtoname(cdev), name) == 0)
  325                         return (1);
  326         return (0);
  327 }
  328 
  329 void
  330 dev_depends(dev_t pdev, dev_t cdev)
  331 {
  332 
  333         cdev->si_parent = pdev;
  334         cdev->si_flags |= SI_CHILD;
  335         LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
  336 }
  337 
  338 dev_t
  339 make_dev_alias(dev_t pdev, const char *fmt, ...)
  340 {
  341         dev_t   dev;
  342         va_list ap;
  343         int i;
  344 
  345         dev = allocdev();
  346         dev->si_flags |= SI_ALIAS;
  347         dev->si_flags |= SI_NAMED;
  348         dev_depends(pdev, dev);
  349         va_start(ap, fmt);
  350         i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
  351         dev->si_name[i] = '\0';
  352         va_end(ap);
  353 
  354         if (devfs_create_hook)
  355                 devfs_create_hook(dev);
  356         return (dev);
  357 }
  358 
  359 void
  360 revoke_and_destroy_dev(dev_t dev)
  361 {
  362         struct vnode *vp;
  363 
  364         GIANT_REQUIRED;
  365 
  366         vp = SLIST_FIRST(&dev->si_hlist);
  367         if (vp != NULL)
  368                 VOP_REVOKE(vp, REVOKEALL);
  369         destroy_dev(dev);
  370 }
  371 
  372 void
  373 destroy_dev(dev_t dev)
  374 {
  375         
  376         if (!(dev->si_flags & SI_NAMED)) {
  377                 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
  378                     major(dev), minor(dev));
  379                 panic("don't do that");
  380                 return;
  381         }
  382                 
  383         if (devfs_destroy_hook)
  384                 devfs_destroy_hook(dev);
  385         if (dev->si_flags & SI_CHILD) {
  386                 LIST_REMOVE(dev, si_siblings);
  387                 dev->si_flags &= ~SI_CHILD;
  388         }
  389         while (!LIST_EMPTY(&dev->si_children))
  390                 destroy_dev(LIST_FIRST(&dev->si_children));
  391         dev->si_drv1 = 0;
  392         dev->si_drv2 = 0;
  393         dev->si_devsw = 0;
  394         bzero(&dev->__si_u, sizeof(dev->__si_u));
  395         dev->si_flags &= ~SI_NAMED;
  396         dev->si_flags &= ~SI_ALIAS;
  397         freedev(dev);
  398 }
  399 
  400 const char *
  401 devtoname(dev_t dev)
  402 {
  403         char *p;
  404         int mynor;
  405 
  406         if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
  407                 p = dev->si_name;
  408                 if (devsw(dev))
  409                         sprintf(p, "#%s/", devsw(dev)->d_name);
  410                 else
  411                         sprintf(p, "#%d/", major(dev));
  412                 p += strlen(p);
  413                 mynor = minor(dev);
  414                 if (mynor < 0 || mynor > 255)
  415                         sprintf(p, "%#x", (u_int)mynor);
  416                 else
  417                         sprintf(p, "%d", mynor);
  418         }
  419         return (dev->si_name);
  420 }
  421 
  422 int
  423 dev_stdclone(char *name, char **namep, const char *stem, int *unit)
  424 {
  425         int u, i;
  426 
  427         i = strlen(stem);
  428         if (bcmp(stem, name, i) != 0)
  429                 return (0);
  430         if (!isdigit(name[i]))
  431                 return (0);
  432         u = 0;
  433         if (name[i] == '' && isdigit(name[i+1]))
  434                 return (0);
  435         while (isdigit(name[i])) {
  436                 u *= 10;
  437                 u += name[i++] - '';
  438         }
  439         if (u > 0xffffff)
  440                 return (0);
  441         *unit = u;
  442         if (namep)
  443                 *namep = &name[i];
  444         if (name[i]) 
  445                 return (2);
  446         return (1);
  447 }
  448 
  449 /*
  450  * Helper sysctl for devname(3).  We're given a {u}dev_t and return
  451  * the name, if any, registered by the device driver.
  452  */
  453 static int
  454 sysctl_devname(SYSCTL_HANDLER_ARGS)
  455 {
  456         int error;
  457         udev_t ud;
  458         dev_t dev;
  459 
  460         error = SYSCTL_IN(req, &ud, sizeof (ud));
  461         if (error)
  462                 return (error);
  463         if (ud == NOUDEV)
  464                 return(EINVAL);
  465         dev = makedev(umajor(ud), uminor(ud));
  466         if (dev->si_name[0] == '\0')
  467                 error = ENOENT;
  468         else
  469                 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
  470         freedev(dev);
  471         return (error);
  472 }
  473 
  474 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
  475         NULL, 0, sysctl_devname, "", "devname(3) handler");
  476 
  477 /*
  478  * Set ready_for_devs; prior to this point, device creation is not allowed.
  479  */     
  480 static void
  481 dev_set_ready(void *junk)
  482 {
  483         ready_for_devs = 1;
  484 }
  485 
  486 SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL);
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_conf.c

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_conf.c
