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: releng/12.0/sys/fs/devfs/devfs_devs.c 341085 2018-11-27 17:58:25Z markj $
   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 
   62 static MALLOC_DEFINE(M_DEVFS2, "DEVFS2", "DEVFS data 2");
   63 static MALLOC_DEFINE(M_DEVFS3, "DEVFS3", "DEVFS data 3");
   64 static MALLOC_DEFINE(M_CDEVP, "DEVFS1", "DEVFS cdev_priv storage");
   65 
   66 SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "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         cdp->cdp_dirents = &cdp->cdp_dirent0;
  142 
  143         cdev = &cdp->cdp_c;
  144         LIST_INIT(&cdev->si_children);
  145         vfs_timestamp(&ts);
  146         cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
  147 
  148         return (cdev);
  149 }
  150 
  151 int
  152 devfs_dev_exists(const char *name)
  153 {
  154         struct cdev_priv *cdp;
  155 
  156         mtx_assert(&devmtx, MA_OWNED);
  157 
  158         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  159                 if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
  160                         continue;
  161                 if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
  162                         return (1);
  163                 if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
  164                         return (1);
  165         }
  166         if (devfs_dir_find(name) != 0)
  167                 return (1);
  168 
  169         return (0);
  170 }
  171 
  172 void
  173 devfs_free(struct cdev *cdev)
  174 {
  175         struct cdev_priv *cdp;
  176 
  177         cdp = cdev2priv(cdev);
  178         if (cdev->si_cred != NULL)
  179                 crfree(cdev->si_cred);
  180         devfs_free_cdp_inode(cdp->cdp_inode);
  181         if (cdp->cdp_maxdirent > 0) 
  182                 free(cdp->cdp_dirents, M_DEVFS2);
  183         free(cdp, M_CDEVP);
  184 }
  185 
  186 struct devfs_dirent *
  187 devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
  188 {
  189         struct devfs_dirent *de;
  190 
  191         TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
  192                 if (namelen != de->de_dirent->d_namlen)
  193                         continue;
  194                 if (type != 0 && type != de->de_dirent->d_type)
  195                         continue;
  196 
  197                 /*
  198                  * The race with finding non-active name is not
  199                  * completely closed by the check, but it is similar
  200                  * to the devfs_allocv() in making it unlikely enough.
  201                  */
  202                 if (de->de_dirent->d_type == DT_CHR &&
  203                     (de->de_cdp->cdp_flags & CDP_ACTIVE) == 0)
  204                         continue;
  205 
  206                 if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
  207                         continue;
  208                 break;
  209         }
  210         KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
  211             ("devfs_find: returning a doomed entry"));
  212         return (de);
  213 }
  214 
  215 struct devfs_dirent *
  216 devfs_newdirent(char *name, int namelen)
  217 {
  218         int i;
  219         struct devfs_dirent *de;
  220         struct dirent d;
  221 
  222         d.d_namlen = namelen;
  223         i = sizeof(*de) + GENERIC_DIRSIZ(&d);
  224         de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
  225         de->de_dirent = (struct dirent *)(de + 1);
  226         de->de_dirent->d_namlen = namelen;
  227         de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
  228         bcopy(name, de->de_dirent->d_name, namelen);
  229         dirent_terminate(de->de_dirent);
  230         vfs_timestamp(&de->de_ctime);
  231         de->de_mtime = de->de_atime = de->de_ctime;
  232         de->de_links = 1;
  233         de->de_holdcnt = 1;
  234 #ifdef MAC
  235         mac_devfs_init(de);
  236 #endif
  237         return (de);
  238 }
  239 
  240 struct devfs_dirent *
  241 devfs_parent_dirent(struct devfs_dirent *de)
  242 {
  243 
  244         if (de->de_dirent->d_type != DT_DIR)
  245                 return (de->de_dir);
  246 
  247         if (de->de_flags & (DE_DOT | DE_DOTDOT))
  248                 return (NULL);
  249 
  250         de = TAILQ_FIRST(&de->de_dlist);        /* "." */
  251         if (de == NULL)
  252                 return (NULL);
  253         de = TAILQ_NEXT(de, de_list);           /* ".." */
  254         if (de == NULL)
  255                 return (NULL);
  256 
  257         return (de->de_dir);
  258 }
  259 
  260 struct devfs_dirent *
  261 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen,
  262     struct devfs_dirent *dotdot, u_int inode)
  263 {
  264         struct devfs_dirent *dd;
  265         struct devfs_dirent *de;
  266 
  267         /* Create the new directory */
  268         dd = devfs_newdirent(name, namelen);
  269         TAILQ_INIT(&dd->de_dlist);
  270         dd->de_dirent->d_type = DT_DIR;
  271         dd->de_mode = 0555;
  272         dd->de_links = 2;
  273         dd->de_dir = dd;
  274         if (inode != 0)
  275                 dd->de_inode = inode;
  276         else
  277                 dd->de_inode = alloc_unr(devfs_inos);
  278 
  279         /*
  280          * "." and ".." are always the two first entries in the
  281          * de_dlist list.
  282          *
  283          * Create the "." entry in the new directory.
  284          */
  285         de = devfs_newdirent(".", 1);
  286         de->de_dirent->d_type = DT_DIR;
  287         de->de_flags |= DE_DOT;
  288         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  289         de->de_dir = dd;
  290 
  291         /* Create the ".." entry in the new directory. */
  292         de = devfs_newdirent("..", 2);
  293         de->de_dirent->d_type = DT_DIR;
  294         de->de_flags |= DE_DOTDOT;
  295         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  296         if (dotdot == NULL) {
  297                 de->de_dir = dd;
  298         } else {
  299                 de->de_dir = dotdot;
  300                 sx_assert(&dmp->dm_lock, SX_XLOCKED);
  301                 TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
  302                 dotdot->de_links++;
  303                 devfs_rules_apply(dmp, dd);
  304         }
  305 
  306 #ifdef MAC
  307         mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
  308 #endif
  309         return (dd);
  310 }
  311 
  312 void
  313 devfs_dirent_free(struct devfs_dirent *de)
  314 {
  315         struct vnode *vp;
  316 
  317         vp = de->de_vnode;
  318         mtx_lock(&devfs_de_interlock);
  319         if (vp != NULL && vp->v_data == de)
  320                 vp->v_data = NULL;
  321         mtx_unlock(&devfs_de_interlock);
  322         free(de, M_DEVFS3);
  323 }
  324 
  325 /*
  326  * Removes a directory if it is empty. Also empty parent directories are
  327  * removed recursively.
  328  */
  329 static void
  330 devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
  331 {
  332         struct devfs_dirent *dd, *de_dot, *de_dotdot;
  333 
  334         sx_assert(&dm->dm_lock, SX_XLOCKED);
  335 
  336         for (;;) {
  337                 KASSERT(de->de_dirent->d_type == DT_DIR,
  338                     ("devfs_rmdir_empty: de is not a directory"));
  339 
  340                 if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
  341                         return;
  342 
  343                 de_dot = TAILQ_FIRST(&de->de_dlist);
  344                 KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
  345                 de_dotdot = TAILQ_NEXT(de_dot, de_list);
  346                 KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
  347                 /* Return if the directory is not empty. */
  348                 if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
  349                         return;
  350 
  351                 dd = devfs_parent_dirent(de);
  352                 KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
  353                 TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
  354                 TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
  355                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  356                 DEVFS_DE_HOLD(dd);
  357                 devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  358                 devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
  359                 devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
  360                 if (DEVFS_DE_DROP(dd)) {
  361                         devfs_dirent_free(dd);
  362                         return;
  363                 }
  364 
  365                 de = dd;
  366         }
  367 }
  368 
  369 /*
  370  * The caller needs to hold the dm for the duration of the call since
  371  * dm->dm_lock may be temporary dropped.
  372  */
  373 void
  374 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
  375 {
  376         struct devfs_dirent *dd;
  377         struct vnode *vp;
  378 
  379         KASSERT((de->de_flags & DE_DOOMED) == 0,
  380                 ("devfs_delete doomed dirent"));
  381         de->de_flags |= DE_DOOMED;
  382 
  383         if ((flags & DEVFS_DEL_NORECURSE) == 0) {
  384                 dd = devfs_parent_dirent(de);
  385                 if (dd != NULL)
  386                         DEVFS_DE_HOLD(dd);
  387                 if (de->de_flags & DE_USER) {
  388                         KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
  389                         devfs_dir_unref_de(dm, dd);
  390                 }
  391         } else
  392                 dd = NULL;
  393 
  394         mtx_lock(&devfs_de_interlock);
  395         vp = de->de_vnode;
  396         if (vp != NULL) {
  397                 VI_LOCK(vp);
  398                 mtx_unlock(&devfs_de_interlock);
  399                 vholdl(vp);
  400                 sx_unlock(&dm->dm_lock);
  401                 if ((flags & DEVFS_DEL_VNLOCKED) == 0)
  402                         vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
  403                 else
  404                         VI_UNLOCK(vp);
  405                 vgone(vp);
  406                 if ((flags & DEVFS_DEL_VNLOCKED) == 0)
  407                         VOP_UNLOCK(vp, 0);
  408                 vdrop(vp);
  409                 sx_xlock(&dm->dm_lock);
  410         } else
  411                 mtx_unlock(&devfs_de_interlock);
  412         if (de->de_symlink) {
  413                 free(de->de_symlink, M_DEVFS);
  414                 de->de_symlink = NULL;
  415         }
  416 #ifdef MAC
  417         mac_devfs_destroy(de);
  418 #endif
  419         if (de->de_inode > DEVFS_ROOTINO) {
  420                 devfs_free_cdp_inode(de->de_inode);
  421                 de->de_inode = 0;
  422         }
  423         if (DEVFS_DE_DROP(de))
  424                 devfs_dirent_free(de);
  425 
  426         if (dd != NULL) {
  427                 if (DEVFS_DE_DROP(dd))
  428                         devfs_dirent_free(dd);
  429                 else
  430                         devfs_rmdir_empty(dm, dd);
  431         }
  432 }
  433 
  434 /*
  435  * Called on unmount.
  436  * Recursively removes the entire tree.
  437  * The caller needs to hold the dm for the duration of the call.
  438  */
  439 
  440 static void
  441 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
  442 {
  443         struct devfs_dirent *de;
  444 
  445         sx_assert(&dm->dm_lock, SX_XLOCKED);
  446 
  447         DEVFS_DE_HOLD(dd);
  448         for (;;) {
  449                 /*
  450                  * Use TAILQ_LAST() to remove "." and ".." last.
  451                  * We might need ".." to resolve a path in
  452                  * devfs_dir_unref_de().
  453                  */
  454                 de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
  455                 if (de == NULL)
  456                         break;
  457                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  458                 if (de->de_flags & DE_USER)
  459                         devfs_dir_unref_de(dm, dd);
  460                 if (de->de_flags & (DE_DOT | DE_DOTDOT))
  461                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  462                 else if (de->de_dirent->d_type == DT_DIR)
  463                         devfs_purge(dm, de);
  464                 else
  465                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  466         }
  467         if (DEVFS_DE_DROP(dd))
  468                 devfs_dirent_free(dd);
  469         else if ((dd->de_flags & DE_DOOMED) == 0)
  470                 devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
  471 }
  472 
  473 /*
  474  * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
  475  * by the mount points dm_idx.
  476  * This function extends the array when necessary, taking into account that
  477  * the default array is 1 element and not malloc'ed.
  478  */
  479 static void
  480 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
  481 {
  482         struct devfs_dirent **dep;
  483         int siz;
  484 
  485         siz = (dm->dm_idx + 1) * sizeof *dep;
  486         dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
  487         dev_lock();
  488         if (dm->dm_idx <= cdp->cdp_maxdirent) {
  489                 /* We got raced */
  490                 dev_unlock();
  491                 free(dep, M_DEVFS2);
  492                 return;
  493         } 
  494         memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
  495         if (cdp->cdp_maxdirent > 0)
  496                 free(cdp->cdp_dirents, M_DEVFS2);
  497         cdp->cdp_dirents = dep;
  498         /*
  499          * XXX: if malloc told us how much we actually got this could
  500          * XXX: be optimized.
  501          */
  502         cdp->cdp_maxdirent = dm->dm_idx;
  503         dev_unlock();
  504 }
  505 
  506 /*
  507  * The caller needs to hold the dm for the duration of the call.
  508  */
  509 static int
  510 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
  511 {
  512         struct cdev_priv *cdp;
  513         struct devfs_dirent *de;
  514         struct devfs_dirent *dd, *dt;
  515         struct cdev *pdev;
  516         int de_flags, depth, j;
  517         char *q, *s;
  518 
  519         sx_assert(&dm->dm_lock, SX_XLOCKED);
  520         dev_lock();
  521         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  522 
  523                 KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
  524 
  525                 /*
  526                  * If we are unmounting, or the device has been destroyed,
  527                  * clean up our dirent.
  528                  */
  529                 if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
  530                     dm->dm_idx <= cdp->cdp_maxdirent &&
  531                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  532                         de = cdp->cdp_dirents[dm->dm_idx];
  533                         cdp->cdp_dirents[dm->dm_idx] = NULL;
  534                         KASSERT(cdp == de->de_cdp,
  535                             ("%s %d %s %p %p", __func__, __LINE__,
  536                             cdp->cdp_c.si_name, cdp, de->de_cdp));
  537                         KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
  538                         dev_unlock();
  539 
  540                         TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
  541                         de->de_cdp = NULL;
  542                         de->de_inode = 0;
  543                         devfs_delete(dm, de, 0);
  544                         dev_lock();
  545                         cdp->cdp_inuse--;
  546                         dev_unlock();
  547                         return (1);
  548                 }
  549                 /*
  550                  * GC any lingering devices
  551                  */
  552                 if (!(cdp->cdp_flags & CDP_ACTIVE)) {
  553                         if (cdp->cdp_inuse > 0)
  554                                 continue;
  555                         TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
  556                         dev_unlock();
  557                         dev_rel(&cdp->cdp_c);
  558                         return (1);
  559                 }
  560                 /*
  561                  * Don't create any new dirents if we are unmounting
  562                  */
  563                 if (cleanup)
  564                         continue;
  565                 KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
  566 
  567                 if (dm->dm_idx <= cdp->cdp_maxdirent &&
  568                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  569                         de = cdp->cdp_dirents[dm->dm_idx];
  570                         KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
  571                         continue;
  572                 }
  573 
  574 
  575                 cdp->cdp_inuse++;
  576                 dev_unlock();
  577 
  578                 if (dm->dm_idx > cdp->cdp_maxdirent)
  579                         devfs_metoo(cdp, dm);
  580 
  581                 dd = dm->dm_rootdir;
  582                 s = cdp->cdp_c.si_name;
  583                 for (;;) {
  584                         for (q = s; *q != '/' && *q != '\0'; q++)
  585                                 continue;
  586                         if (*q != '/')
  587                                 break;
  588                         de = devfs_find(dd, s, q - s, 0);
  589                         if (de == NULL)
  590                                 de = devfs_vmkdir(dm, s, q - s, dd, 0);
  591                         else if (de->de_dirent->d_type == DT_LNK) {
  592                                 de = devfs_find(dd, s, q - s, DT_DIR);
  593                                 if (de == NULL)
  594                                         de = devfs_vmkdir(dm, s, q - s, dd, 0);
  595                                 de->de_flags |= DE_COVERED;
  596                         }
  597                         s = q + 1;
  598                         dd = de;
  599                         KASSERT(dd->de_dirent->d_type == DT_DIR &&
  600                             (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
  601                             ("%s: invalid directory (si_name=%s)",
  602                             __func__, cdp->cdp_c.si_name));
  603 
  604                 }
  605                 de_flags = 0;
  606                 de = devfs_find(dd, s, q - s, DT_LNK);
  607                 if (de != NULL)
  608                         de_flags |= DE_COVERED;
  609 
  610                 de = devfs_newdirent(s, q - s);
  611                 if (cdp->cdp_c.si_flags & SI_ALIAS) {
  612                         de->de_uid = 0;
  613                         de->de_gid = 0;
  614                         de->de_mode = 0755;
  615                         de->de_dirent->d_type = DT_LNK;
  616                         pdev = cdp->cdp_c.si_parent;
  617                         dt = dd;
  618                         depth = 0;
  619                         while (dt != dm->dm_rootdir &&
  620                             (dt = devfs_parent_dirent(dt)) != NULL)
  621                                 depth++;
  622                         j = depth * 3 + strlen(pdev->si_name) + 1;
  623                         de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
  624                         de->de_symlink[0] = 0;
  625                         while (depth-- > 0)
  626                                 strcat(de->de_symlink, "../");
  627                         strcat(de->de_symlink, pdev->si_name);
  628                 } else {
  629                         de->de_uid = cdp->cdp_c.si_uid;
  630                         de->de_gid = cdp->cdp_c.si_gid;
  631                         de->de_mode = cdp->cdp_c.si_mode;
  632                         de->de_dirent->d_type = DT_CHR;
  633                 }
  634                 de->de_flags |= de_flags;
  635                 de->de_inode = cdp->cdp_inode;
  636                 de->de_cdp = cdp;
  637 #ifdef MAC
  638                 mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
  639                     &cdp->cdp_c, de);
  640 #endif
  641                 de->de_dir = dd;
  642                 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  643                 devfs_rules_apply(dm, de);
  644                 dev_lock();
  645                 /* XXX: could check that cdp is still active here */
  646                 KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
  647                     ("%s %d\n", __func__, __LINE__));
  648                 cdp->cdp_dirents[dm->dm_idx] = de;
  649                 KASSERT(de->de_cdp != (void *)0xdeadc0de,
  650                     ("%s %d\n", __func__, __LINE__));
  651                 dev_unlock();
  652                 return (1);
  653         }
  654         dev_unlock();
  655         return (0);
  656 }
  657 
  658 /*
  659  * The caller needs to hold the dm for the duration of the call.
  660  */
  661 void
  662 devfs_populate(struct devfs_mount *dm)
  663 {
  664         unsigned gen;
  665 
  666         sx_assert(&dm->dm_lock, SX_XLOCKED);
  667         gen = devfs_generation;
  668         if (dm->dm_generation == gen)
  669                 return;
  670         while (devfs_populate_loop(dm, 0))
  671                 continue;
  672         dm->dm_generation = gen;
  673 }
  674 
  675 /*
  676  * The caller needs to hold the dm for the duration of the call.
  677  */
  678 void
  679 devfs_cleanup(struct devfs_mount *dm)
  680 {
  681 
  682         sx_assert(&dm->dm_lock, SX_XLOCKED);
  683         while (devfs_populate_loop(dm, 1))
  684                 continue;
  685         devfs_purge(dm, dm->dm_rootdir);
  686 }
  687 
  688 /*
  689  * devfs_create() and devfs_destroy() are called from kern_conf.c and
  690  * in both cases the devlock() mutex is held, so no further locking
  691  * is necessary and no sleeping allowed.
  692  */
  693 
  694 void
  695 devfs_create(struct cdev *dev)
  696 {
  697         struct cdev_priv *cdp;
  698 
  699         mtx_assert(&devmtx, MA_OWNED);
  700         cdp = cdev2priv(dev);
  701         cdp->cdp_flags |= CDP_ACTIVE;
  702         cdp->cdp_inode = alloc_unrl(devfs_inos);
  703         dev_refl(dev);
  704         TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
  705         devfs_generation++;
  706 }
  707 
  708 void
  709 devfs_destroy(struct cdev *dev)
  710 {
  711         struct cdev_priv *cdp;
  712 
  713         mtx_assert(&devmtx, MA_OWNED);
  714         cdp = cdev2priv(dev);
  715         cdp->cdp_flags &= ~CDP_ACTIVE;
  716         devfs_generation++;
  717 }
  718 
  719 ino_t
  720 devfs_alloc_cdp_inode(void)
  721 {
  722 
  723         return (alloc_unr(devfs_inos));
  724 }
  725 
  726 void
  727 devfs_free_cdp_inode(ino_t ino)
  728 {
  729 
  730         if (ino > 0)
  731                 free_unr(devfs_inos, ino);
  732 }
  733 
  734 static void
  735 devfs_devs_init(void *junk __unused)
  736 {
  737 
  738         devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
  739 }
  740 
  741 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
