devfs_devs.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2000,2004
    5  *      Poul-Henning Kamp.  All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Neither the name of the University nor the names of its contributors
   13  *    may be used to endorse or promote products derived from this software
   14  *    without specific prior written permission.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  *
   28  * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
   29  *
   30  * $FreeBSD$
   31  */
   32 
   33 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #include <sys/conf.h>
   36 #include <sys/dirent.h>
   37 #include <sys/kernel.h>
   38 #include <sys/limits.h>
   39 #include <sys/lock.h>
   40 #include <sys/malloc.h>
   41 #include <sys/proc.h>
   42 #include <sys/sx.h>
   43 #include <sys/sysctl.h>
   44 #include <sys/vnode.h>
   45 
   46 #include <sys/kdb.h>
   47 
   48 #include <fs/devfs/devfs.h>
   49 #include <fs/devfs/devfs_int.h>
   50 
   51 #include <security/mac/mac_framework.h>
   52 
   53 /*
   54  * The one true (but secret) list of active devices in the system.
   55  * Locked by dev_lock()/devmtx
   56  */
   57 struct cdev_priv_list cdevp_list = TAILQ_HEAD_INITIALIZER(cdevp_list);
   58 
   59 struct unrhdr *devfs_inos;
   60 
   61 static MALLOC_DEFINE(M_DEVFS2, "DEVFS2", "DEVFS data 2");
   62 static MALLOC_DEFINE(M_DEVFS3, "DEVFS3", "DEVFS data 3");
   63 static MALLOC_DEFINE(M_CDEVP, "DEVFS1", "DEVFS cdev_priv storage");
   64 
   65 SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
   66     "DEVFS filesystem");
   67 
   68 static unsigned devfs_generation;
   69 SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD,
   70         &devfs_generation, 0, "DEVFS generation number");
   71 
   72 unsigned devfs_rule_depth = 1;
   73 SYSCTL_UINT(_vfs_devfs, OID_AUTO, rule_depth, CTLFLAG_RW,
   74         &devfs_rule_depth, 0, "Max depth of ruleset include");
   75 
   76 /*
   77  * Helper sysctl for devname(3).  We're given a dev_t and return the
   78  * name, if any, registered by the device driver.
   79  */
   80 static int
   81 sysctl_devname(SYSCTL_HANDLER_ARGS)
   82 {
   83         int error;
   84         dev_t ud;
   85 #ifdef COMPAT_FREEBSD11
   86         uint32_t ud_compat;
   87 #endif
   88         struct cdev_priv *cdp;
   89         struct cdev *dev;
   90 
   91 #ifdef COMPAT_FREEBSD11
   92         if (req->newlen == sizeof(ud_compat)) {
   93                 error = SYSCTL_IN(req, &ud_compat, sizeof(ud_compat));
   94                 if (error == 0)
   95                         ud = ud_compat == (uint32_t)NODEV ? NODEV : ud_compat;
   96         } else
   97 #endif
   98                 error = SYSCTL_IN(req, &ud, sizeof (ud));
   99         if (error)
  100                 return (error);
  101         if (ud == NODEV)
  102                 return (EINVAL);
  103         dev = NULL;
  104         dev_lock();
  105         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list)
  106                 if (cdp->cdp_inode == ud) {
  107                         dev = &cdp->cdp_c;
  108                         dev_refl(dev);
  109                         break;
  110                 }
  111         dev_unlock();
  112         if (dev == NULL)
  113                 return (ENOENT);
  114         error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
  115         dev_rel(dev);
  116         return (error);
  117 }
  118 
  119 SYSCTL_PROC(_kern, OID_AUTO, devname,
  120     CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY|CTLFLAG_MPSAFE,
  121     NULL, 0, sysctl_devname, "", "devname(3) handler");
  122 
  123 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev, CTLFLAG_RD,
  124     SYSCTL_NULL_INT_PTR, sizeof(struct cdev), "sizeof(struct cdev)");
  125 
  126 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLAG_RD,
  127     SYSCTL_NULL_INT_PTR, sizeof(struct cdev_priv), "sizeof(struct cdev_priv)");
  128 
  129 struct cdev *
  130 devfs_alloc(int flags)
  131 {
  132         struct cdev_priv *cdp;
  133         struct cdev *cdev;
  134         struct timespec ts;
  135 
  136         cdp = malloc(sizeof *cdp, M_CDEVP, M_ZERO |
  137             ((flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK));
  138         if (cdp == NULL)
  139                 return (NULL);
  140 
  141         mtx_init(&cdp->cdp_threadlock, "devthrd", NULL, MTX_DEF);
  142 
  143         cdp->cdp_dirents = &cdp->cdp_dirent0;
  144 
  145         cdev = &cdp->cdp_c;
  146         LIST_INIT(&cdev->si_children);
  147         vfs_timestamp(&ts);
  148         cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
  149 
  150         return (cdev);
  151 }
  152 
  153 int
  154 devfs_dev_exists(const char *name)
  155 {
  156         struct cdev_priv *cdp;
  157 
  158         dev_lock_assert_locked();
  159 
  160         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  161                 if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
  162                         continue;
  163                 if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
  164                         return (1);
  165                 if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
  166                         return (1);
  167         }
  168         if (devfs_dir_find(name) != 0)
  169                 return (1);
  170 
  171         return (0);
  172 }
  173 
  174 void
  175 devfs_free(struct cdev *cdev)
  176 {
  177         struct cdev_priv *cdp;
  178 
  179         cdp = cdev2priv(cdev);
  180         if (cdev->si_cred != NULL)
  181                 crfree(cdev->si_cred);
  182         devfs_free_cdp_inode(cdp->cdp_inode);
  183         if (cdp->cdp_maxdirent > 0) 
  184                 free(cdp->cdp_dirents, M_DEVFS2);
  185         mtx_destroy(&cdp->cdp_threadlock);
  186         free(cdp, M_CDEVP);
  187 }
  188 
  189 struct devfs_dirent *
  190 devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
  191 {
  192         struct devfs_dirent *de;
  193 
  194         TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
  195                 if (namelen != de->de_dirent->d_namlen)
  196                         continue;
  197                 if (type != 0 && type != de->de_dirent->d_type)
  198                         continue;
  199 
  200                 /*
  201                  * The race with finding non-active name is not
  202                  * completely closed by the check, but it is similar
  203                  * to the devfs_allocv() in making it unlikely enough.
  204                  */
  205                 if (de->de_dirent->d_type == DT_CHR &&
  206                     (de->de_cdp->cdp_flags & CDP_ACTIVE) == 0)
  207                         continue;
  208 
  209                 if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
  210                         continue;
  211                 break;
  212         }
  213         KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
  214             ("devfs_find: returning a doomed entry"));
  215         return (de);
  216 }
  217 
  218 struct devfs_dirent *
  219 devfs_newdirent(char *name, int namelen)
  220 {
  221         int i;
  222         struct devfs_dirent *de;
  223         struct dirent d;
  224 
  225         d.d_namlen = namelen;
  226         i = sizeof(*de) + GENERIC_DIRSIZ(&d);
  227         de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
  228         de->de_dirent = (struct dirent *)(de + 1);
  229         de->de_dirent->d_namlen = namelen;
  230         de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
  231         bcopy(name, de->de_dirent->d_name, namelen);
  232         dirent_terminate(de->de_dirent);
  233         vfs_timestamp(&de->de_ctime);
  234         de->de_mtime = de->de_atime = de->de_ctime;
  235         de->de_links = 1;
  236         de->de_holdcnt = 1;
  237 #ifdef MAC
  238         mac_devfs_init(de);
  239 #endif
  240         return (de);
  241 }
  242 
  243 struct devfs_dirent *
  244 devfs_parent_dirent(struct devfs_dirent *de)
  245 {
  246 
  247         if (de->de_dirent->d_type != DT_DIR)
  248                 return (de->de_dir);
  249 
  250         if (de->de_flags & (DE_DOT | DE_DOTDOT))
  251                 return (NULL);
  252 
  253         de = TAILQ_FIRST(&de->de_dlist);        /* "." */
  254         if (de == NULL)
  255                 return (NULL);
  256         de = TAILQ_NEXT(de, de_list);           /* ".." */
  257         if (de == NULL)
  258                 return (NULL);
  259 
  260         return (de->de_dir);
  261 }
  262 
  263 struct devfs_dirent *
  264 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen,
  265     struct devfs_dirent *dotdot, u_int inode)
  266 {
  267         struct devfs_dirent *dd;
  268         struct devfs_dirent *de;
  269 
  270         /* Create the new directory */
  271         dd = devfs_newdirent(name, namelen);
  272         TAILQ_INIT(&dd->de_dlist);
  273         dd->de_dirent->d_type = DT_DIR;
  274         dd->de_mode = 0555;
  275         dd->de_links = 2;
  276         dd->de_dir = dd;
  277         if (inode != 0)
  278                 dd->de_inode = inode;
  279         else
  280                 dd->de_inode = alloc_unr(devfs_inos);
  281 
  282         /*
  283          * "." and ".." are always the two first entries in the
  284          * de_dlist list.
  285          *
  286          * Create the "." entry in the new directory.
  287          */
  288         de = devfs_newdirent(".", 1);
  289         de->de_dirent->d_type = DT_DIR;
  290         de->de_flags |= DE_DOT;
  291         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  292         de->de_dir = dd;
  293 
  294         /* Create the ".." entry in the new directory. */
  295         de = devfs_newdirent("..", 2);
  296         de->de_dirent->d_type = DT_DIR;
  297         de->de_flags |= DE_DOTDOT;
  298         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  299         if (dotdot == NULL) {
  300                 de->de_dir = dd;
  301         } else {
  302                 de->de_dir = dotdot;
  303                 sx_assert(&dmp->dm_lock, SX_XLOCKED);
  304                 TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
  305                 dotdot->de_links++;
  306                 devfs_rules_apply(dmp, dd);
  307         }
  308 
  309 #ifdef MAC
  310         mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
  311 #endif
  312         return (dd);
  313 }
  314 
  315 void
  316 devfs_dirent_free(struct devfs_dirent *de)
  317 {
  318         struct vnode *vp;
  319 
  320         vp = de->de_vnode;
  321         mtx_lock(&devfs_de_interlock);
  322         if (vp != NULL && vp->v_data == de)
  323                 vp->v_data = NULL;
  324         mtx_unlock(&devfs_de_interlock);
  325         free(de, M_DEVFS3);
  326 }
  327 
  328 /*
  329  * Removes a directory if it is empty. Also empty parent directories are
  330  * removed recursively.
  331  */
  332 static void
  333 devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
  334 {
  335         struct devfs_dirent *dd, *de_dot, *de_dotdot;
  336 
  337         sx_assert(&dm->dm_lock, SX_XLOCKED);
  338 
  339         for (;;) {
  340                 KASSERT(de->de_dirent->d_type == DT_DIR,
  341                     ("devfs_rmdir_empty: de is not a directory"));
  342 
  343                 if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
  344                         return;
  345 
  346                 de_dot = TAILQ_FIRST(&de->de_dlist);
  347                 KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
  348                 de_dotdot = TAILQ_NEXT(de_dot, de_list);
  349                 KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
  350                 /* Return if the directory is not empty. */
  351                 if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
  352                         return;
  353 
  354                 dd = devfs_parent_dirent(de);
  355                 KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
  356                 TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
  357                 TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
  358                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  359                 DEVFS_DE_HOLD(dd);
  360                 devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  361                 devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
  362                 devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
  363                 if (DEVFS_DE_DROP(dd)) {
  364                         devfs_dirent_free(dd);
  365                         return;
  366                 }
  367 
  368                 de = dd;
  369         }
  370 }
  371 
  372 /*
  373  * The caller needs to hold the dm for the duration of the call since
  374  * dm->dm_lock may be temporary dropped.
  375  */
  376 void
  377 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
  378 {
  379         struct devfs_dirent *dd;
  380         struct vnode *vp;
  381 
  382         KASSERT((de->de_flags & DE_DOOMED) == 0,
  383                 ("devfs_delete doomed dirent"));
  384         de->de_flags |= DE_DOOMED;
  385 
  386         if ((flags & DEVFS_DEL_NORECURSE) == 0) {
  387                 dd = devfs_parent_dirent(de);
  388                 if (dd != NULL)
  389                         DEVFS_DE_HOLD(dd);
  390                 if (de->de_flags & DE_USER) {
  391                         KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
  392                         devfs_dir_unref_de(dm, dd);
  393                 }
  394         } else
  395                 dd = NULL;
  396 
  397         mtx_lock(&devfs_de_interlock);
  398         vp = de->de_vnode;
  399         if (vp != NULL) {
  400                 vhold(vp);
  401                 mtx_unlock(&devfs_de_interlock);
  402                 sx_unlock(&dm->dm_lock);
  403                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
  404                 vgone(vp);
  405                 VOP_UNLOCK(vp);
  406                 vdrop(vp);
  407                 sx_xlock(&dm->dm_lock);
  408         } else
  409                 mtx_unlock(&devfs_de_interlock);
  410         if (de->de_symlink) {
  411                 free(de->de_symlink, M_DEVFS);
  412                 de->de_symlink = NULL;
  413         }
  414 #ifdef MAC
  415         mac_devfs_destroy(de);
  416 #endif
  417         if (de->de_inode > DEVFS_ROOTINO) {
  418                 devfs_free_cdp_inode(de->de_inode);
  419                 de->de_inode = 0;
  420         }
  421         if (DEVFS_DE_DROP(de))
  422                 devfs_dirent_free(de);
  423 
  424         if (dd != NULL) {
  425                 if (DEVFS_DE_DROP(dd))
  426                         devfs_dirent_free(dd);
  427                 else
  428                         devfs_rmdir_empty(dm, dd);
  429         }
  430 }
  431 
  432 /*
  433  * Called on unmount.
  434  * Recursively removes the entire tree.
  435  * The caller needs to hold the dm for the duration of the call.
  436  */
  437 
  438 static void
  439 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
  440 {
  441         struct devfs_dirent *de;
  442 
  443         sx_assert(&dm->dm_lock, SX_XLOCKED);
  444 
  445         DEVFS_DE_HOLD(dd);
  446         for (;;) {
  447                 /*
  448                  * Use TAILQ_LAST() to remove "." and ".." last.
  449                  * We might need ".." to resolve a path in
  450                  * devfs_dir_unref_de().
  451                  */
  452                 de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
  453                 if (de == NULL)
  454                         break;
  455                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  456                 if (de->de_flags & DE_USER)
  457                         devfs_dir_unref_de(dm, dd);
  458                 if (de->de_flags & (DE_DOT | DE_DOTDOT))
  459                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  460                 else if (de->de_dirent->d_type == DT_DIR)
  461                         devfs_purge(dm, de);
  462                 else
  463                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  464         }
  465         if (DEVFS_DE_DROP(dd))
  466                 devfs_dirent_free(dd);
  467         else if ((dd->de_flags & DE_DOOMED) == 0)
  468                 devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
  469 }
  470 
  471 /*
  472  * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
  473  * by the mount points dm_idx.
  474  * This function extends the array when necessary, taking into account that
  475  * the default array is 1 element and not malloc'ed.
  476  */
  477 static void
  478 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
  479 {
  480         struct devfs_dirent **dep, **olddep;
  481         int siz;
  482 
  483         siz = (dm->dm_idx + 1) * sizeof *dep;
  484         dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
  485         dev_lock();
  486         if (dm->dm_idx <= cdp->cdp_maxdirent) {
  487                 /* We got raced */
  488                 dev_unlock();
  489                 free(dep, M_DEVFS2);
  490                 return;
  491         } 
  492         memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
  493         olddep = cdp->cdp_maxdirent > 0 ? cdp->cdp_dirents : NULL;
  494         cdp->cdp_dirents = dep;
  495         /*
  496          * XXX: if malloc told us how much we actually got this could
  497          * XXX: be optimized.
  498          */
  499         cdp->cdp_maxdirent = dm->dm_idx;
  500         dev_unlock();
  501         free(olddep, M_DEVFS2);
  502 }
  503 
  504 /*
  505  * The caller needs to hold the dm for the duration of the call.
  506  */
  507 static int
  508 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
  509 {
  510         struct cdev_priv *cdp;
  511         struct devfs_dirent *de;
  512         struct devfs_dirent *dd, *dt;
  513         struct cdev *pdev;
  514         int de_flags, depth, j;
  515         char *q, *s;
  516 
  517         sx_assert(&dm->dm_lock, SX_XLOCKED);
  518         dev_lock();
  519         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  520                 KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
  521 
  522                 /*
  523                  * If we are unmounting, or the device has been destroyed,
  524                  * clean up our dirent.
  525                  */
  526                 if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
  527                     dm->dm_idx <= cdp->cdp_maxdirent &&
  528                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  529                         de = cdp->cdp_dirents[dm->dm_idx];
  530                         cdp->cdp_dirents[dm->dm_idx] = NULL;
  531                         KASSERT(cdp == de->de_cdp,
  532                             ("%s %d %s %p %p", __func__, __LINE__,
  533                             cdp->cdp_c.si_name, cdp, de->de_cdp));
  534                         KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
  535                         dev_unlock();
  536 
  537                         TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
  538                         de->de_cdp = NULL;
  539                         de->de_inode = 0;
  540                         devfs_delete(dm, de, 0);
  541                         dev_lock();
  542                         cdp->cdp_inuse--;
  543                         dev_unlock();
  544                         return (1);
  545                 }
  546                 /*
  547                  * GC any lingering devices
  548                  */
  549                 if (!(cdp->cdp_flags & CDP_ACTIVE)) {
  550                         if (cdp->cdp_inuse > 0)
  551                                 continue;
  552                         TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
  553                         dev_unlock();
  554                         dev_rel(&cdp->cdp_c);
  555                         return (1);
  556                 }
  557                 /*
  558                  * Don't create any new dirents if we are unmounting
  559                  */
  560                 if (cleanup)
  561                         continue;
  562                 KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
  563 
  564                 if (dm->dm_idx <= cdp->cdp_maxdirent &&
  565                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  566                         de = cdp->cdp_dirents[dm->dm_idx];
  567                         KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
  568                         continue;
  569                 }
  570 
  571                 cdp->cdp_inuse++;
  572                 dev_unlock();
  573 
  574                 if (dm->dm_idx > cdp->cdp_maxdirent)
  575                         devfs_metoo(cdp, dm);
  576 
  577                 dd = dm->dm_rootdir;
  578                 s = cdp->cdp_c.si_name;
  579                 for (;;) {
  580                         for (q = s; *q != '/' && *q != '\0'; q++)
  581                                 continue;
  582                         if (*q != '/')
  583                                 break;
  584                         de = devfs_find(dd, s, q - s, 0);
  585                         if (de == NULL)
  586                                 de = devfs_vmkdir(dm, s, q - s, dd, 0);
  587                         else if (de->de_dirent->d_type == DT_LNK) {
  588                                 de = devfs_find(dd, s, q - s, DT_DIR);
  589                                 if (de == NULL)
  590                                         de = devfs_vmkdir(dm, s, q - s, dd, 0);
  591                                 de->de_flags |= DE_COVERED;
  592                         }
  593                         s = q + 1;
  594                         dd = de;
  595                         KASSERT(dd->de_dirent->d_type == DT_DIR &&
  596                             (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
  597                             ("%s: invalid directory (si_name=%s)",
  598                             __func__, cdp->cdp_c.si_name));
  599                 }
  600                 de_flags = 0;
  601                 de = devfs_find(dd, s, q - s, DT_LNK);
  602                 if (de != NULL)
  603                         de_flags |= DE_COVERED;
  604 
  605                 de = devfs_newdirent(s, q - s);
  606                 if (cdp->cdp_c.si_flags & SI_ALIAS) {
  607                         de->de_uid = 0;
  608                         de->de_gid = 0;
  609                         de->de_mode = 0755;
  610                         de->de_dirent->d_type = DT_LNK;
  611                         pdev = cdp->cdp_c.si_parent;
  612                         dt = dd;
  613                         depth = 0;
  614                         while (dt != dm->dm_rootdir &&
  615                             (dt = devfs_parent_dirent(dt)) != NULL)
  616                                 depth++;
  617                         j = depth * 3 + strlen(pdev->si_name) + 1;
  618                         de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
  619                         de->de_symlink[0] = 0;
  620                         while (depth-- > 0)
  621                                 strcat(de->de_symlink, "../");
  622                         strcat(de->de_symlink, pdev->si_name);
  623                 } else {
  624                         de->de_uid = cdp->cdp_c.si_uid;
  625                         de->de_gid = cdp->cdp_c.si_gid;
  626                         de->de_mode = cdp->cdp_c.si_mode;
  627                         de->de_dirent->d_type = DT_CHR;
  628                 }
  629                 de->de_flags |= de_flags;
  630                 de->de_inode = cdp->cdp_inode;
  631                 de->de_cdp = cdp;
  632 #ifdef MAC
  633                 mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
  634                     &cdp->cdp_c, de);
  635 #endif
  636                 de->de_dir = dd;
  637                 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  638                 devfs_rules_apply(dm, de);
  639                 dev_lock();
  640                 /* XXX: could check that cdp is still active here */
  641                 KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
  642                     ("%s %d\n", __func__, __LINE__));
  643                 cdp->cdp_dirents[dm->dm_idx] = de;
  644                 KASSERT(de->de_cdp != (void *)0xdeadc0de,
  645                     ("%s %d\n", __func__, __LINE__));
  646                 dev_unlock();
  647                 return (1);
  648         }
  649         dev_unlock();
  650         return (0);
  651 }
  652 
  653 int
  654 devfs_populate_needed(struct devfs_mount *dm)
  655 {
  656 
  657         return (dm->dm_generation != devfs_generation);
  658 }
  659 
  660 /*
  661  * The caller needs to hold the dm for the duration of the call.
  662  */
  663 void
  664 devfs_populate(struct devfs_mount *dm)
  665 {
  666         unsigned gen;
  667 
  668         sx_assert(&dm->dm_lock, SX_XLOCKED);
  669         if (!devfs_populate_needed(dm))
  670                 return;
  671         gen = devfs_generation;
  672         while (devfs_populate_loop(dm, 0))
  673                 continue;
  674         dm->dm_generation = gen;
  675 }
  676 
  677 /*
  678  * The caller needs to hold the dm for the duration of the call.
  679  */
  680 void
  681 devfs_cleanup(struct devfs_mount *dm)
  682 {
  683 
  684         sx_assert(&dm->dm_lock, SX_XLOCKED);
  685         while (devfs_populate_loop(dm, 1))
  686                 continue;
  687         devfs_purge(dm, dm->dm_rootdir);
  688 }
  689 
  690 /*
  691  * devfs_create() and devfs_destroy() are called from kern_conf.c and
  692  * in both cases the devlock() mutex is held, so no further locking
  693  * is necessary and no sleeping allowed.
  694  */
  695 
  696 void
  697 devfs_create(struct cdev *dev)
  698 {
  699         struct cdev_priv *cdp;
  700 
  701         dev_lock_assert_locked();
  702         cdp = cdev2priv(dev);
  703         cdp->cdp_flags |= CDP_ACTIVE;
  704         cdp->cdp_inode = alloc_unrl(devfs_inos);
  705         dev_refl(dev);
  706         TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
  707         devfs_generation++;
  708 }
  709 
  710 void
  711 devfs_destroy(struct cdev *dev)
  712 {
  713         struct cdev_priv *cdp;
  714 
  715         dev_lock_assert_locked();
  716         cdp = cdev2priv(dev);
  717         cdp->cdp_flags &= ~CDP_ACTIVE;
  718         devfs_generation++;
  719 }
  720 
  721 ino_t
  722 devfs_alloc_cdp_inode(void)
  723 {
  724 
  725         return (alloc_unr(devfs_inos));
  726 }
  727 
  728 void
  729 devfs_free_cdp_inode(ino_t ino)
  730 {
  731 
  732         if (ino > 0)
  733                 free_unr(devfs_inos, ino);
  734 }
  735 
  736 static void
  737 devfs_devs_init(void *junk __unused)
  738 {
  739 
  740         devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
  741 }
  742 
  743 SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);
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FreeBSD/Linux Kernel Cross Reference sys/fs/devfs/devfs_devs.c

FreeBSD/Linux Kernel Cross Reference
sys/fs/devfs/devfs_devs.c
