The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/fs/devfs/devfs_devs.c

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    1 /*-
    2  * Copyright (c) 2000,2004
    3  *      Poul-Henning Kamp.  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. Neither the name of the University nor the names of its contributors
   11  *    may be used to endorse or promote products derived from this software
   12  *    without specific prior written permission.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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  * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
   27  *
   28  * $FreeBSD$
   29  */
   30 
   31 #include <sys/param.h>
   32 #include <sys/systm.h>
   33 #include <sys/conf.h>
   34 #include <sys/dirent.h>
   35 #include <sys/kernel.h>
   36 #include <sys/limits.h>
   37 #include <sys/lock.h>
   38 #include <sys/malloc.h>
   39 #include <sys/proc.h>
   40 #include <sys/sx.h>
   41 #include <sys/sysctl.h>
   42 #include <sys/vnode.h>
   43 
   44 #include <sys/kdb.h>
   45 
   46 #include <fs/devfs/devfs.h>
   47 #include <fs/devfs/devfs_int.h>
   48 
   49 #include <security/mac/mac_framework.h>
   50 
   51 /*
   52  * The one true (but secret) list of active devices in the system.
   53  * Locked by dev_lock()/devmtx
   54  */
   55 struct cdev_priv_list cdevp_list = TAILQ_HEAD_INITIALIZER(cdevp_list);
   56 
   57 struct unrhdr *devfs_inos;
   58 
   59 
   60 static MALLOC_DEFINE(M_DEVFS2, "DEVFS2", "DEVFS data 2");
   61 static MALLOC_DEFINE(M_DEVFS3, "DEVFS3", "DEVFS data 3");
   62 static MALLOC_DEFINE(M_CDEVP, "DEVFS1", "DEVFS cdev_priv storage");
   63 
   64 static SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem");
   65 
   66 static unsigned devfs_generation;
   67 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD,
   68         &devfs_generation, 0, "DEVFS generation number");
   69 
   70 unsigned devfs_rule_depth = 1;
   71 SYSCTL_UINT(_vfs_devfs, OID_AUTO, rule_depth, CTLFLAG_RW,
   72         &devfs_rule_depth, 0, "Max depth of ruleset include");
   73 
   74 /*
   75  * Helper sysctl for devname(3).  We're given a dev_t and return the
   76  * name, if any, registered by the device driver.
   77  */
   78 static int
   79 sysctl_devname(SYSCTL_HANDLER_ARGS)
   80 {
   81         int error;
   82         dev_t ud;
   83         struct cdev_priv *cdp;
   84         struct cdev *dev;
   85 
   86         error = SYSCTL_IN(req, &ud, sizeof (ud));
   87         if (error)
   88                 return (error);
   89         if (ud == NODEV)
   90                 return (EINVAL);
   91         dev = NULL;
   92         dev_lock();
   93         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list)
   94                 if (cdp->cdp_inode == ud) {
   95                         dev = &cdp->cdp_c;
   96                         dev_refl(dev);
   97                         break;
   98                 }
   99         dev_unlock();
  100         if (dev == NULL)
  101                 return (ENOENT);
  102         error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
  103         dev_rel(dev);
  104         return (error);
  105 }
  106 
  107 SYSCTL_PROC(_kern, OID_AUTO, devname,
  108     CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY|CTLFLAG_MPSAFE,
  109     NULL, 0, sysctl_devname, "", "devname(3) handler");
  110 
  111 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev, CTLFLAG_RD,
  112     SYSCTL_NULL_INT_PTR, sizeof(struct cdev), "sizeof(struct cdev)");
  113 
  114 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLAG_RD,
  115     SYSCTL_NULL_INT_PTR, sizeof(struct cdev_priv), "sizeof(struct cdev_priv)");
  116 
  117 struct cdev *
  118 devfs_alloc(int flags)
  119 {
  120         struct cdev_priv *cdp;
  121         struct cdev *cdev;
  122         struct timespec ts;
  123 
  124         cdp = malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZERO |
  125             ((flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK));
  126         if (cdp == NULL)
  127                 return (NULL);
  128 
  129         cdp->cdp_dirents = &cdp->cdp_dirent0;
  130         cdp->cdp_dirent0 = NULL;
  131         cdp->cdp_maxdirent = 0;
  132         cdp->cdp_inode = 0;
  133 
  134         cdev = &cdp->cdp_c;
  135 
  136         cdev->si_name = cdev->__si_namebuf;
  137         LIST_INIT(&cdev->si_children);
  138         vfs_timestamp(&ts);
  139         cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
  140         cdev->si_cred = NULL;
  141 
  142         return (cdev);
  143 }
  144 
  145 int
  146 devfs_dev_exists(const char *name)
  147 {
  148         struct cdev_priv *cdp;
  149 
  150         mtx_assert(&devmtx, MA_OWNED);
  151 
  152         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  153                 if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
  154                         continue;
  155                 if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
  156                         return (1);
  157                 if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
  158                         return (1);
  159         }
  160         if (devfs_dir_find(name) != 0)
  161                 return (1);
  162 
  163         return (0);
  164 }
  165 
  166 void
  167 devfs_free(struct cdev *cdev)
  168 {
  169         struct cdev_priv *cdp;
  170 
  171         cdp = cdev2priv(cdev);
  172         if (cdev->si_cred != NULL)
  173                 crfree(cdev->si_cred);
  174         devfs_free_cdp_inode(cdp->cdp_inode);
  175         if (cdp->cdp_maxdirent > 0) 
  176                 free(cdp->cdp_dirents, M_DEVFS2);
  177         free(cdp, M_CDEVP);
  178 }
  179 
  180 struct devfs_dirent *
  181 devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
  182 {
  183         struct devfs_dirent *de;
  184 
  185         TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
  186                 if (namelen != de->de_dirent->d_namlen)
  187                         continue;
  188                 if (type != 0 && type != de->de_dirent->d_type)
  189                         continue;
  190                 if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
  191                         continue;
  192                 break;
  193         }
  194         KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
  195             ("devfs_find: returning a doomed entry"));
  196         return (de);
  197 }
  198 
  199 struct devfs_dirent *
  200 devfs_newdirent(char *name, int namelen)
  201 {
  202         int i;
  203         struct devfs_dirent *de;
  204         struct dirent d;
  205 
  206         d.d_namlen = namelen;
  207         i = sizeof (*de) + GENERIC_DIRSIZ(&d); 
  208         de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
  209         de->de_dirent = (struct dirent *)(de + 1);
  210         de->de_dirent->d_namlen = namelen;
  211         de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
  212         bcopy(name, de->de_dirent->d_name, namelen);
  213         de->de_dirent->d_name[namelen] = '\0';
  214         vfs_timestamp(&de->de_ctime);
  215         de->de_mtime = de->de_atime = de->de_ctime;
  216         de->de_links = 1;
  217         de->de_holdcnt = 1;
  218 #ifdef MAC
  219         mac_devfs_init(de);
  220 #endif
  221         return (de);
  222 }
  223 
  224 struct devfs_dirent *
  225 devfs_parent_dirent(struct devfs_dirent *de)
  226 {
  227 
  228         if (de->de_dirent->d_type != DT_DIR)
  229                 return (de->de_dir);
  230 
  231         if (de->de_flags & (DE_DOT | DE_DOTDOT))
  232                 return (NULL);
  233 
  234         de = TAILQ_FIRST(&de->de_dlist);        /* "." */
  235         if (de == NULL)
  236                 return (NULL);
  237         de = TAILQ_NEXT(de, de_list);           /* ".." */
  238         if (de == NULL)
  239                 return (NULL);
  240 
  241         return (de->de_dir);
  242 }
  243 
  244 struct devfs_dirent *
  245 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode)
  246 {
  247         struct devfs_dirent *dd;
  248         struct devfs_dirent *de;
  249 
  250         /* Create the new directory */
  251         dd = devfs_newdirent(name, namelen);
  252         TAILQ_INIT(&dd->de_dlist);
  253         dd->de_dirent->d_type = DT_DIR;
  254         dd->de_mode = 0555;
  255         dd->de_links = 2;
  256         dd->de_dir = dd;
  257         if (inode != 0)
  258                 dd->de_inode = inode;
  259         else
  260                 dd->de_inode = alloc_unr(devfs_inos);
  261 
  262         /*
  263          * "." and ".." are always the two first entries in the
  264          * de_dlist list.
  265          *
  266          * Create the "." entry in the new directory.
  267          */
  268         de = devfs_newdirent(".", 1);
  269         de->de_dirent->d_type = DT_DIR;
  270         de->de_flags |= DE_DOT;
  271         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  272         de->de_dir = dd;
  273 
  274         /* Create the ".." entry in the new directory. */
  275         de = devfs_newdirent("..", 2);
  276         de->de_dirent->d_type = DT_DIR;
  277         de->de_flags |= DE_DOTDOT;
  278         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  279         if (dotdot == NULL) {
  280                 de->de_dir = dd;
  281         } else {
  282                 de->de_dir = dotdot;
  283                 sx_assert(&dmp->dm_lock, SX_XLOCKED);
  284                 TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
  285                 dotdot->de_links++;
  286                 devfs_rules_apply(dmp, dd);
  287         }
  288 
  289 #ifdef MAC
  290         mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
  291 #endif
  292         return (dd);
  293 }
  294 
  295 void
  296 devfs_dirent_free(struct devfs_dirent *de)
  297 {
  298         free(de, M_DEVFS3);
  299 }
  300 
  301 /*
  302  * Removes a directory if it is empty. Also empty parent directories are
  303  * removed recursively.
  304  */
  305 static void
  306 devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
  307 {
  308         struct devfs_dirent *dd, *de_dot, *de_dotdot;
  309 
  310         sx_assert(&dm->dm_lock, SX_XLOCKED);
  311 
  312         for (;;) {
  313                 KASSERT(de->de_dirent->d_type == DT_DIR,
  314                     ("devfs_rmdir_empty: de is not a directory"));
  315 
  316                 if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
  317                         return;
  318 
  319                 de_dot = TAILQ_FIRST(&de->de_dlist);
  320                 KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
  321                 de_dotdot = TAILQ_NEXT(de_dot, de_list);
  322                 KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
  323                 /* Return if the directory is not empty. */
  324                 if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
  325                         return;
  326 
  327                 dd = devfs_parent_dirent(de);
  328                 KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
  329                 TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
  330                 TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
  331                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  332                 DEVFS_DE_HOLD(dd);
  333                 devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  334                 devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
  335                 devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
  336                 if (DEVFS_DE_DROP(dd)) {
  337                         devfs_dirent_free(dd);
  338                         return;
  339                 }
  340 
  341                 de = dd;
  342         }
  343 }
  344 
  345 /*
  346  * The caller needs to hold the dm for the duration of the call since
  347  * dm->dm_lock may be temporary dropped.
  348  */
  349 void
  350 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
  351 {
  352         struct devfs_dirent *dd;
  353         struct vnode *vp;
  354 
  355         KASSERT((de->de_flags & DE_DOOMED) == 0,
  356                 ("devfs_delete doomed dirent"));
  357         de->de_flags |= DE_DOOMED;
  358 
  359         if ((flags & DEVFS_DEL_NORECURSE) == 0) {
  360                 dd = devfs_parent_dirent(de);
  361                 if (dd != NULL)
  362                         DEVFS_DE_HOLD(dd);
  363                 if (de->de_flags & DE_USER) {
  364                         KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
  365                         devfs_dir_unref_de(dm, dd);
  366                 }
  367         } else
  368                 dd = NULL;
  369 
  370         mtx_lock(&devfs_de_interlock);
  371         vp = de->de_vnode;
  372         if (vp != NULL) {
  373                 VI_LOCK(vp);
  374                 mtx_unlock(&devfs_de_interlock);
  375                 vholdl(vp);
  376                 sx_unlock(&dm->dm_lock);
  377                 if ((flags & DEVFS_DEL_VNLOCKED) == 0)
  378                         vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
  379                 else
  380                         VI_UNLOCK(vp);
  381                 vgone(vp);
  382                 if ((flags & DEVFS_DEL_VNLOCKED) == 0)
  383                         VOP_UNLOCK(vp, 0);
  384                 vdrop(vp);
  385                 sx_xlock(&dm->dm_lock);
  386         } else
  387                 mtx_unlock(&devfs_de_interlock);
  388         if (de->de_symlink) {
  389                 free(de->de_symlink, M_DEVFS);
  390                 de->de_symlink = NULL;
  391         }
  392 #ifdef MAC
  393         mac_devfs_destroy(de);
  394 #endif
  395         if (de->de_inode > DEVFS_ROOTINO) {
  396                 devfs_free_cdp_inode(de->de_inode);
  397                 de->de_inode = 0;
  398         }
  399         if (DEVFS_DE_DROP(de))
  400                 devfs_dirent_free(de);
  401 
  402         if (dd != NULL) {
  403                 if (DEVFS_DE_DROP(dd))
  404                         devfs_dirent_free(dd);
  405                 else
  406                         devfs_rmdir_empty(dm, dd);
  407         }
  408 }
  409 
  410 /*
  411  * Called on unmount.
  412  * Recursively removes the entire tree.
  413  * The caller needs to hold the dm for the duration of the call.
  414  */
  415 
  416 static void
  417 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
  418 {
  419         struct devfs_dirent *de;
  420 
  421         sx_assert(&dm->dm_lock, SX_XLOCKED);
  422 
  423         DEVFS_DE_HOLD(dd);
  424         for (;;) {
  425                 /*
  426                  * Use TAILQ_LAST() to remove "." and ".." last.
  427                  * We might need ".." to resolve a path in
  428                  * devfs_dir_unref_de().
  429                  */
  430                 de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
  431                 if (de == NULL)
  432                         break;
  433                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  434                 if (de->de_flags & DE_USER)
  435                         devfs_dir_unref_de(dm, dd);
  436                 if (de->de_flags & (DE_DOT | DE_DOTDOT))
  437                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  438                 else if (de->de_dirent->d_type == DT_DIR)
  439                         devfs_purge(dm, de);
  440                 else
  441                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  442         }
  443         if (DEVFS_DE_DROP(dd))
  444                 devfs_dirent_free(dd);
  445         else if ((dd->de_flags & DE_DOOMED) == 0)
  446                 devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
  447 }
  448 
  449 /*
  450  * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
  451  * by the mount points dm_idx.
  452  * This function extends the array when necessary, taking into account that
  453  * the default array is 1 element and not malloc'ed.
  454  */
  455 static void
  456 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
  457 {
  458         struct devfs_dirent **dep;
  459         int siz;
  460 
  461         siz = (dm->dm_idx + 1) * sizeof *dep;
  462         dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
  463         dev_lock();
  464         if (dm->dm_idx <= cdp->cdp_maxdirent) {
  465                 /* We got raced */
  466                 dev_unlock();
  467                 free(dep, M_DEVFS2);
  468                 return;
  469         } 
  470         memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
  471         if (cdp->cdp_maxdirent > 0)
  472                 free(cdp->cdp_dirents, M_DEVFS2);
  473         cdp->cdp_dirents = dep;
  474         /*
  475          * XXX: if malloc told us how much we actually got this could
  476          * XXX: be optimized.
  477          */
  478         cdp->cdp_maxdirent = dm->dm_idx;
  479         dev_unlock();
  480 }
  481 
  482 /*
  483  * The caller needs to hold the dm for the duration of the call.
  484  */
  485 static int
  486 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
  487 {
  488         struct cdev_priv *cdp;
  489         struct devfs_dirent *de;
  490         struct devfs_dirent *dd;
  491         struct cdev *pdev;
  492         int de_flags, j;
  493         char *q, *s;
  494 
  495         sx_assert(&dm->dm_lock, SX_XLOCKED);
  496         dev_lock();
  497         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  498 
  499                 KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
  500 
  501                 /*
  502                  * If we are unmounting, or the device has been destroyed,
  503                  * clean up our dirent.
  504                  */
  505                 if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
  506                     dm->dm_idx <= cdp->cdp_maxdirent &&
  507                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  508                         de = cdp->cdp_dirents[dm->dm_idx];
  509                         cdp->cdp_dirents[dm->dm_idx] = NULL;
  510                         KASSERT(cdp == de->de_cdp,
  511                             ("%s %d %s %p %p", __func__, __LINE__,
  512                             cdp->cdp_c.si_name, cdp, de->de_cdp));
  513                         KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
  514                         dev_unlock();
  515 
  516                         TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
  517                         de->de_cdp = NULL;
  518                         de->de_inode = 0;
  519                         devfs_delete(dm, de, 0);
  520                         dev_lock();
  521                         cdp->cdp_inuse--;
  522                         dev_unlock();
  523                         return (1);
  524                 }
  525                 /*
  526                  * GC any lingering devices
  527                  */
  528                 if (!(cdp->cdp_flags & CDP_ACTIVE)) {
  529                         if (cdp->cdp_inuse > 0)
  530                                 continue;
  531                         TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
  532                         dev_unlock();
  533                         dev_rel(&cdp->cdp_c);
  534                         return (1);
  535                 }
  536                 /*
  537                  * Don't create any new dirents if we are unmounting
  538                  */
  539                 if (cleanup)
  540                         continue;
  541                 KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
  542 
  543                 if (dm->dm_idx <= cdp->cdp_maxdirent &&
  544                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  545                         de = cdp->cdp_dirents[dm->dm_idx];
  546                         KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
  547                         continue;
  548                 }
  549 
  550 
  551                 cdp->cdp_inuse++;
  552                 dev_unlock();
  553 
  554                 if (dm->dm_idx > cdp->cdp_maxdirent)
  555                         devfs_metoo(cdp, dm);
  556 
  557                 dd = dm->dm_rootdir;
  558                 s = cdp->cdp_c.si_name;
  559                 for (;;) {
  560                         for (q = s; *q != '/' && *q != '\0'; q++)
  561                                 continue;
  562                         if (*q != '/')
  563                                 break;
  564                         de = devfs_find(dd, s, q - s, 0);
  565                         if (de == NULL)
  566                                 de = devfs_vmkdir(dm, s, q - s, dd, 0);
  567                         else if (de->de_dirent->d_type == DT_LNK) {
  568                                 de = devfs_find(dd, s, q - s, DT_DIR);
  569                                 if (de == NULL)
  570                                         de = devfs_vmkdir(dm, s, q - s, dd, 0);
  571                                 de->de_flags |= DE_COVERED;
  572                         }
  573                         s = q + 1;
  574                         dd = de;
  575                         KASSERT(dd->de_dirent->d_type == DT_DIR &&
  576                             (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
  577                             ("%s: invalid directory (si_name=%s)",
  578                             __func__, cdp->cdp_c.si_name));
  579 
  580                 }
  581                 de_flags = 0;
  582                 de = devfs_find(dd, s, q - s, DT_LNK);
  583                 if (de != NULL)
  584                         de_flags |= DE_COVERED;
  585 
  586                 de = devfs_newdirent(s, q - s);
  587                 if (cdp->cdp_c.si_flags & SI_ALIAS) {
  588                         de->de_uid = 0;
  589                         de->de_gid = 0;
  590                         de->de_mode = 0755;
  591                         de->de_dirent->d_type = DT_LNK;
  592                         pdev = cdp->cdp_c.si_parent;
  593                         j = strlen(pdev->si_name) + 1;
  594                         de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
  595                         bcopy(pdev->si_name, de->de_symlink, j);
  596                 } else {
  597                         de->de_uid = cdp->cdp_c.si_uid;
  598                         de->de_gid = cdp->cdp_c.si_gid;
  599                         de->de_mode = cdp->cdp_c.si_mode;
  600                         de->de_dirent->d_type = DT_CHR;
  601                 }
  602                 de->de_flags |= de_flags;
  603                 de->de_inode = cdp->cdp_inode;
  604                 de->de_cdp = cdp;
  605 #ifdef MAC
  606                 mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
  607                     &cdp->cdp_c, de);
  608 #endif
  609                 de->de_dir = dd;
  610                 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  611                 devfs_rules_apply(dm, de);
  612                 dev_lock();
  613                 /* XXX: could check that cdp is still active here */
  614                 KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
  615                     ("%s %d\n", __func__, __LINE__));
  616                 cdp->cdp_dirents[dm->dm_idx] = de;
  617                 KASSERT(de->de_cdp != (void *)0xdeadc0de,
  618                     ("%s %d\n", __func__, __LINE__));
  619                 dev_unlock();
  620                 return (1);
  621         }
  622         dev_unlock();
  623         return (0);
  624 }
  625 
  626 /*
  627  * The caller needs to hold the dm for the duration of the call.
  628  */
  629 void
  630 devfs_populate(struct devfs_mount *dm)
  631 {
  632         unsigned gen;
  633 
  634         sx_assert(&dm->dm_lock, SX_XLOCKED);
  635         gen = devfs_generation;
  636         if (dm->dm_generation == gen)
  637                 return;
  638         while (devfs_populate_loop(dm, 0))
  639                 continue;
  640         dm->dm_generation = gen;
  641 }
  642 
  643 /*
  644  * The caller needs to hold the dm for the duration of the call.
  645  */
  646 void
  647 devfs_cleanup(struct devfs_mount *dm)
  648 {
  649 
  650         sx_assert(&dm->dm_lock, SX_XLOCKED);
  651         while (devfs_populate_loop(dm, 1))
  652                 continue;
  653         devfs_purge(dm, dm->dm_rootdir);
  654 }
  655 
  656 /*
  657  * devfs_create() and devfs_destroy() are called from kern_conf.c and
  658  * in both cases the devlock() mutex is held, so no further locking
  659  * is necesary and no sleeping allowed.
  660  */
  661 
  662 void
  663 devfs_create(struct cdev *dev)
  664 {
  665         struct cdev_priv *cdp;
  666 
  667         mtx_assert(&devmtx, MA_OWNED);
  668         cdp = cdev2priv(dev);
  669         cdp->cdp_flags |= CDP_ACTIVE;
  670         cdp->cdp_inode = alloc_unrl(devfs_inos);
  671         dev_refl(dev);
  672         TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
  673         devfs_generation++;
  674 }
  675 
  676 void
  677 devfs_destroy(struct cdev *dev)
  678 {
  679         struct cdev_priv *cdp;
  680 
  681         mtx_assert(&devmtx, MA_OWNED);
  682         cdp = cdev2priv(dev);
  683         cdp->cdp_flags &= ~CDP_ACTIVE;
  684         devfs_generation++;
  685 }
  686 
  687 ino_t
  688 devfs_alloc_cdp_inode(void)
  689 {
  690 
  691         return (alloc_unr(devfs_inos));
  692 }
  693 
  694 void
  695 devfs_free_cdp_inode(ino_t ino)
  696 {
  697 
  698         if (ino > 0)
  699                 free_unr(devfs_inos, ino);
  700 }
  701 
  702 static void
  703 devfs_devs_init(void *junk __unused)
  704 {
  705 
  706         devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
  707 }
  708 
  709 SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);

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