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: releng/10.0/sys/fs/devfs/devfs_devs.c 249583 2013-04-17 11:42:40Z gabor $
   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     0, sizeof(struct cdev), "sizeof(struct cdev)");
  113 
  114 SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLAG_RD,
  115     0, 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_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         LIST_INIT(&cdev->si_children);
  137         vfs_timestamp(&ts);
  138         cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
  139         cdev->si_cred = NULL;
  140 
  141         return (cdev);
  142 }
  143 
  144 int
  145 devfs_dev_exists(const char *name)
  146 {
  147         struct cdev_priv *cdp;
  148 
  149         mtx_assert(&devmtx, MA_OWNED);
  150 
  151         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  152                 if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
  153                         continue;
  154                 if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
  155                         return (1);
  156                 if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
  157                         return (1);
  158         }
  159         if (devfs_dir_find(name) != 0)
  160                 return (1);
  161 
  162         return (0);
  163 }
  164 
  165 void
  166 devfs_free(struct cdev *cdev)
  167 {
  168         struct cdev_priv *cdp;
  169 
  170         cdp = cdev2priv(cdev);
  171         if (cdev->si_cred != NULL)
  172                 crfree(cdev->si_cred);
  173         devfs_free_cdp_inode(cdp->cdp_inode);
  174         if (cdp->cdp_maxdirent > 0) 
  175                 free(cdp->cdp_dirents, M_DEVFS2);
  176         free(cdp, M_CDEVP);
  177 }
  178 
  179 struct devfs_dirent *
  180 devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
  181 {
  182         struct devfs_dirent *de;
  183 
  184         TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
  185                 if (namelen != de->de_dirent->d_namlen)
  186                         continue;
  187                 if (type != 0 && type != de->de_dirent->d_type)
  188                         continue;
  189                 if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
  190                         continue;
  191                 break;
  192         }
  193         KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
  194             ("devfs_find: returning a doomed entry"));
  195         return (de);
  196 }
  197 
  198 struct devfs_dirent *
  199 devfs_newdirent(char *name, int namelen)
  200 {
  201         int i;
  202         struct devfs_dirent *de;
  203         struct dirent d;
  204 
  205         d.d_namlen = namelen;
  206         i = sizeof (*de) + GENERIC_DIRSIZ(&d); 
  207         de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
  208         de->de_dirent = (struct dirent *)(de + 1);
  209         de->de_dirent->d_namlen = namelen;
  210         de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
  211         bcopy(name, de->de_dirent->d_name, namelen);
  212         de->de_dirent->d_name[namelen] = '\0';
  213         vfs_timestamp(&de->de_ctime);
  214         de->de_mtime = de->de_atime = de->de_ctime;
  215         de->de_links = 1;
  216         de->de_holdcnt = 1;
  217 #ifdef MAC
  218         mac_devfs_init(de);
  219 #endif
  220         return (de);
  221 }
  222 
  223 struct devfs_dirent *
  224 devfs_parent_dirent(struct devfs_dirent *de)
  225 {
  226 
  227         if (de->de_dirent->d_type != DT_DIR)
  228                 return (de->de_dir);
  229 
  230         if (de->de_flags & (DE_DOT | DE_DOTDOT))
  231                 return (NULL);
  232 
  233         de = TAILQ_FIRST(&de->de_dlist);        /* "." */
  234         if (de == NULL)
  235                 return (NULL);
  236         de = TAILQ_NEXT(de, de_list);           /* ".." */
  237         if (de == NULL)
  238                 return (NULL);
  239 
  240         return (de->de_dir);
  241 }
  242 
  243 struct devfs_dirent *
  244 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode)
  245 {
  246         struct devfs_dirent *dd;
  247         struct devfs_dirent *de;
  248 
  249         /* Create the new directory */
  250         dd = devfs_newdirent(name, namelen);
  251         TAILQ_INIT(&dd->de_dlist);
  252         dd->de_dirent->d_type = DT_DIR;
  253         dd->de_mode = 0555;
  254         dd->de_links = 2;
  255         dd->de_dir = dd;
  256         if (inode != 0)
  257                 dd->de_inode = inode;
  258         else
  259                 dd->de_inode = alloc_unr(devfs_inos);
  260 
  261         /*
  262          * "." and ".." are always the two first entries in the
  263          * de_dlist list.
  264          *
  265          * Create the "." entry in the new directory.
  266          */
  267         de = devfs_newdirent(".", 1);
  268         de->de_dirent->d_type = DT_DIR;
  269         de->de_flags |= DE_DOT;
  270         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  271         de->de_dir = dd;
  272 
  273         /* Create the ".." entry in the new directory. */
  274         de = devfs_newdirent("..", 2);
  275         de->de_dirent->d_type = DT_DIR;
  276         de->de_flags |= DE_DOTDOT;
  277         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  278         if (dotdot == NULL) {
  279                 de->de_dir = dd;
  280         } else {
  281                 de->de_dir = dotdot;
  282                 sx_assert(&dmp->dm_lock, SX_XLOCKED);
  283                 TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
  284                 dotdot->de_links++;
  285                 devfs_rules_apply(dmp, dd);
  286         }
  287 
  288 #ifdef MAC
  289         mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
  290 #endif
  291         return (dd);
  292 }
  293 
  294 void
  295 devfs_dirent_free(struct devfs_dirent *de)
  296 {
  297         free(de, M_DEVFS3);
  298 }
  299 
  300 /*
  301  * Removes a directory if it is empty. Also empty parent directories are
  302  * removed recursively.
  303  */
  304 static void
  305 devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
  306 {
  307         struct devfs_dirent *dd, *de_dot, *de_dotdot;
  308 
  309         sx_assert(&dm->dm_lock, SX_XLOCKED);
  310 
  311         for (;;) {
  312                 KASSERT(de->de_dirent->d_type == DT_DIR,
  313                     ("devfs_rmdir_empty: de is not a directory"));
  314 
  315                 if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
  316                         return;
  317 
  318                 de_dot = TAILQ_FIRST(&de->de_dlist);
  319                 KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
  320                 de_dotdot = TAILQ_NEXT(de_dot, de_list);
  321                 KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
  322                 /* Return if the directory is not empty. */
  323                 if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
  324                         return;
  325 
  326                 dd = devfs_parent_dirent(de);
  327                 KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
  328                 TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
  329                 TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
  330                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  331                 DEVFS_DE_HOLD(dd);
  332                 devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  333                 devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
  334                 devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
  335                 if (DEVFS_DE_DROP(dd)) {
  336                         devfs_dirent_free(dd);
  337                         return;
  338                 }
  339 
  340                 de = dd;
  341         }
  342 }
  343 
  344 /*
  345  * The caller needs to hold the dm for the duration of the call since
  346  * dm->dm_lock may be temporary dropped.
  347  */
  348 void
  349 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
  350 {
  351         struct devfs_dirent *dd;
  352         struct vnode *vp;
  353 
  354         KASSERT((de->de_flags & DE_DOOMED) == 0,
  355                 ("devfs_delete doomed dirent"));
  356         de->de_flags |= DE_DOOMED;
  357 
  358         if ((flags & DEVFS_DEL_NORECURSE) == 0) {
  359                 dd = devfs_parent_dirent(de);
  360                 if (dd != NULL)
  361                         DEVFS_DE_HOLD(dd);
  362                 if (de->de_flags & DE_USER) {
  363                         KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
  364                         devfs_dir_unref_de(dm, dd);
  365                 }
  366         } else
  367                 dd = NULL;
  368 
  369         mtx_lock(&devfs_de_interlock);
  370         vp = de->de_vnode;
  371         if (vp != NULL) {
  372                 VI_LOCK(vp);
  373                 mtx_unlock(&devfs_de_interlock);
  374                 vholdl(vp);
  375                 sx_unlock(&dm->dm_lock);
  376                 if ((flags & DEVFS_DEL_VNLOCKED) == 0)
  377                         vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
  378                 else
  379                         VI_UNLOCK(vp);
  380                 vgone(vp);
  381                 if ((flags & DEVFS_DEL_VNLOCKED) == 0)
  382                         VOP_UNLOCK(vp, 0);
  383                 vdrop(vp);
  384                 sx_xlock(&dm->dm_lock);
  385         } else
  386                 mtx_unlock(&devfs_de_interlock);
  387         if (de->de_symlink) {
  388                 free(de->de_symlink, M_DEVFS);
  389                 de->de_symlink = NULL;
  390         }
  391 #ifdef MAC
  392         mac_devfs_destroy(de);
  393 #endif
  394         if (de->de_inode > DEVFS_ROOTINO) {
  395                 devfs_free_cdp_inode(de->de_inode);
  396                 de->de_inode = 0;
  397         }
  398         if (DEVFS_DE_DROP(de))
  399                 devfs_dirent_free(de);
  400 
  401         if (dd != NULL) {
  402                 if (DEVFS_DE_DROP(dd))
  403                         devfs_dirent_free(dd);
  404                 else
  405                         devfs_rmdir_empty(dm, dd);
  406         }
  407 }
  408 
  409 /*
  410  * Called on unmount.
  411  * Recursively removes the entire tree.
  412  * The caller needs to hold the dm for the duration of the call.
  413  */
  414 
  415 static void
  416 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
  417 {
  418         struct devfs_dirent *de;
  419 
  420         sx_assert(&dm->dm_lock, SX_XLOCKED);
  421 
  422         DEVFS_DE_HOLD(dd);
  423         for (;;) {
  424                 /*
  425                  * Use TAILQ_LAST() to remove "." and ".." last.
  426                  * We might need ".." to resolve a path in
  427                  * devfs_dir_unref_de().
  428                  */
  429                 de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
  430                 if (de == NULL)
  431                         break;
  432                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  433                 if (de->de_flags & DE_USER)
  434                         devfs_dir_unref_de(dm, dd);
  435                 if (de->de_flags & (DE_DOT | DE_DOTDOT))
  436                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  437                 else if (de->de_dirent->d_type == DT_DIR)
  438                         devfs_purge(dm, de);
  439                 else
  440                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  441         }
  442         if (DEVFS_DE_DROP(dd))
  443                 devfs_dirent_free(dd);
  444         else if ((dd->de_flags & DE_DOOMED) == 0)
  445                 devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
  446 }
  447 
  448 /*
  449  * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
  450  * by the mount points dm_idx.
  451  * This function extends the array when necessary, taking into account that
  452  * the default array is 1 element and not malloc'ed.
  453  */
  454 static void
  455 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
  456 {
  457         struct devfs_dirent **dep;
  458         int siz;
  459 
  460         siz = (dm->dm_idx + 1) * sizeof *dep;
  461         dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
  462         dev_lock();
  463         if (dm->dm_idx <= cdp->cdp_maxdirent) {
  464                 /* We got raced */
  465                 dev_unlock();
  466                 free(dep, M_DEVFS2);
  467                 return;
  468         } 
  469         memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
  470         if (cdp->cdp_maxdirent > 0)
  471                 free(cdp->cdp_dirents, M_DEVFS2);
  472         cdp->cdp_dirents = dep;
  473         /*
  474          * XXX: if malloc told us how much we actually got this could
  475          * XXX: be optimized.
  476          */
  477         cdp->cdp_maxdirent = dm->dm_idx;
  478         dev_unlock();
  479 }
  480 
  481 /*
  482  * The caller needs to hold the dm for the duration of the call.
  483  */
  484 static int
  485 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
  486 {
  487         struct cdev_priv *cdp;
  488         struct devfs_dirent *de;
  489         struct devfs_dirent *dd;
  490         struct cdev *pdev;
  491         int de_flags, j;
  492         char *q, *s;
  493 
  494         sx_assert(&dm->dm_lock, SX_XLOCKED);
  495         dev_lock();
  496         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  497 
  498                 KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
  499 
  500                 /*
  501                  * If we are unmounting, or the device has been destroyed,
  502                  * clean up our dirent.
  503                  */
  504                 if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
  505                     dm->dm_idx <= cdp->cdp_maxdirent &&
  506                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  507                         de = cdp->cdp_dirents[dm->dm_idx];
  508                         cdp->cdp_dirents[dm->dm_idx] = NULL;
  509                         KASSERT(cdp == de->de_cdp,
  510                             ("%s %d %s %p %p", __func__, __LINE__,
  511                             cdp->cdp_c.si_name, cdp, de->de_cdp));
  512                         KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
  513                         dev_unlock();
  514 
  515                         TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
  516                         de->de_cdp = NULL;
  517                         de->de_inode = 0;
  518                         devfs_delete(dm, de, 0);
  519                         dev_lock();
  520                         cdp->cdp_inuse--;
  521                         dev_unlock();
  522                         return (1);
  523                 }
  524                 /*
  525                  * GC any lingering devices
  526                  */
  527                 if (!(cdp->cdp_flags & CDP_ACTIVE)) {
  528                         if (cdp->cdp_inuse > 0)
  529                                 continue;
  530                         TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
  531                         dev_unlock();
  532                         dev_rel(&cdp->cdp_c);
  533                         return (1);
  534                 }
  535                 /*
  536                  * Don't create any new dirents if we are unmounting
  537                  */
  538                 if (cleanup)
  539                         continue;
  540                 KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
  541 
  542                 if (dm->dm_idx <= cdp->cdp_maxdirent &&
  543                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  544                         de = cdp->cdp_dirents[dm->dm_idx];
  545                         KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
  546                         continue;
  547                 }
  548 
  549 
  550                 cdp->cdp_inuse++;
  551                 dev_unlock();
  552 
  553                 if (dm->dm_idx > cdp->cdp_maxdirent)
  554                         devfs_metoo(cdp, dm);
  555 
  556                 dd = dm->dm_rootdir;
  557                 s = cdp->cdp_c.si_name;
  558                 for (;;) {
  559                         for (q = s; *q != '/' && *q != '\0'; q++)
  560                                 continue;
  561                         if (*q != '/')
  562                                 break;
  563                         de = devfs_find(dd, s, q - s, 0);
  564                         if (de == NULL)
  565                                 de = devfs_vmkdir(dm, s, q - s, dd, 0);
  566                         else if (de->de_dirent->d_type == DT_LNK) {
  567                                 de = devfs_find(dd, s, q - s, DT_DIR);
  568                                 if (de == NULL)
  569                                         de = devfs_vmkdir(dm, s, q - s, dd, 0);
  570                                 de->de_flags |= DE_COVERED;
  571                         }
  572                         s = q + 1;
  573                         dd = de;
  574                         KASSERT(dd->de_dirent->d_type == DT_DIR &&
  575                             (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
  576                             ("%s: invalid directory (si_name=%s)",
  577                             __func__, cdp->cdp_c.si_name));
  578 
  579                 }
  580                 de_flags = 0;
  581                 de = devfs_find(dd, s, q - s, DT_LNK);
  582                 if (de != NULL)
  583                         de_flags |= DE_COVERED;
  584 
  585                 de = devfs_newdirent(s, q - s);
  586                 if (cdp->cdp_c.si_flags & SI_ALIAS) {
  587                         de->de_uid = 0;
  588                         de->de_gid = 0;
  589                         de->de_mode = 0755;
  590                         de->de_dirent->d_type = DT_LNK;
  591                         pdev = cdp->cdp_c.si_parent;
  592                         j = strlen(pdev->si_name) + 1;
  593                         de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
  594                         bcopy(pdev->si_name, de->de_symlink, j);
  595                 } else {
  596                         de->de_uid = cdp->cdp_c.si_uid;
  597                         de->de_gid = cdp->cdp_c.si_gid;
  598                         de->de_mode = cdp->cdp_c.si_mode;
  599                         de->de_dirent->d_type = DT_CHR;
  600                 }
  601                 de->de_flags |= de_flags;
  602                 de->de_inode = cdp->cdp_inode;
  603                 de->de_cdp = cdp;
  604 #ifdef MAC
  605                 mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
  606                     &cdp->cdp_c, de);
  607 #endif
  608                 de->de_dir = dd;
  609                 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  610                 devfs_rules_apply(dm, de);
  611                 dev_lock();
  612                 /* XXX: could check that cdp is still active here */
  613                 KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
  614                     ("%s %d\n", __func__, __LINE__));
  615                 cdp->cdp_dirents[dm->dm_idx] = de;
  616                 KASSERT(de->de_cdp != (void *)0xdeadc0de,
  617                     ("%s %d\n", __func__, __LINE__));
  618                 dev_unlock();
  619                 return (1);
  620         }
  621         dev_unlock();
  622         return (0);
  623 }
  624 
  625 /*
  626  * The caller needs to hold the dm for the duration of the call.
  627  */
  628 void
  629 devfs_populate(struct devfs_mount *dm)
  630 {
  631         unsigned gen;
  632 
  633         sx_assert(&dm->dm_lock, SX_XLOCKED);
  634         gen = devfs_generation;
  635         if (dm->dm_generation == gen)
  636                 return;
  637         while (devfs_populate_loop(dm, 0))
  638                 continue;
  639         dm->dm_generation = gen;
  640 }
  641 
  642 /*
  643  * The caller needs to hold the dm for the duration of the call.
  644  */
  645 void
  646 devfs_cleanup(struct devfs_mount *dm)
  647 {
  648 
  649         sx_assert(&dm->dm_lock, SX_XLOCKED);
  650         while (devfs_populate_loop(dm, 1))
  651                 continue;
  652         devfs_purge(dm, dm->dm_rootdir);
  653 }
  654 
  655 /*
  656  * devfs_create() and devfs_destroy() are called from kern_conf.c and
  657  * in both cases the devlock() mutex is held, so no further locking
  658  * is necessary and no sleeping allowed.
  659  */
  660 
  661 void
  662 devfs_create(struct cdev *dev)
  663 {
  664         struct cdev_priv *cdp;
  665 
  666         mtx_assert(&devmtx, MA_OWNED);
  667         cdp = cdev2priv(dev);
  668         cdp->cdp_flags |= CDP_ACTIVE;
  669         cdp->cdp_inode = alloc_unrl(devfs_inos);
  670         dev_refl(dev);
  671         TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
  672         devfs_generation++;
  673 }
  674 
  675 void
  676 devfs_destroy(struct cdev *dev)
  677 {
  678         struct cdev_priv *cdp;
  679 
  680         mtx_assert(&devmtx, MA_OWNED);
  681         cdp = cdev2priv(dev);
  682         cdp->cdp_flags &= ~CDP_ACTIVE;
  683         devfs_generation++;
  684 }
  685 
  686 ino_t
  687 devfs_alloc_cdp_inode(void)
  688 {
  689 
  690         return (alloc_unr(devfs_inos));
  691 }
  692 
  693 void
  694 devfs_free_cdp_inode(ino_t ino)
  695 {
  696 
  697         if (ino > 0)
  698                 free_unr(devfs_inos, ino);
  699 }
  700 
  701 static void
  702 devfs_devs_init(void *junk __unused)
  703 {
  704 
  705         devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
  706 }
  707 
  708 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
