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: releng/11.0/sys/fs/devfs/devfs_devs.c 300365 2016-05-21 09:55:32Z kib $
   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 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_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 
  131         cdev = &cdp->cdp_c;
  132         LIST_INIT(&cdev->si_children);
  133         vfs_timestamp(&ts);
  134         cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
  135 
  136         return (cdev);
  137 }
  138 
  139 int
  140 devfs_dev_exists(const char *name)
  141 {
  142         struct cdev_priv *cdp;
  143 
  144         mtx_assert(&devmtx, MA_OWNED);
  145 
  146         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  147                 if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
  148                         continue;
  149                 if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
  150                         return (1);
  151                 if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
  152                         return (1);
  153         }
  154         if (devfs_dir_find(name) != 0)
  155                 return (1);
  156 
  157         return (0);
  158 }
  159 
  160 void
  161 devfs_free(struct cdev *cdev)
  162 {
  163         struct cdev_priv *cdp;
  164 
  165         cdp = cdev2priv(cdev);
  166         if (cdev->si_cred != NULL)
  167                 crfree(cdev->si_cred);
  168         devfs_free_cdp_inode(cdp->cdp_inode);
  169         if (cdp->cdp_maxdirent > 0) 
  170                 free(cdp->cdp_dirents, M_DEVFS2);
  171         free(cdp, M_CDEVP);
  172 }
  173 
  174 struct devfs_dirent *
  175 devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
  176 {
  177         struct devfs_dirent *de;
  178 
  179         TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
  180                 if (namelen != de->de_dirent->d_namlen)
  181                         continue;
  182                 if (type != 0 && type != de->de_dirent->d_type)
  183                         continue;
  184 
  185                 /*
  186                  * The race with finding non-active name is not
  187                  * completely closed by the check, but it is similar
  188                  * to the devfs_allocv() in making it unlikely enough.
  189                  */
  190                 if (de->de_dirent->d_type == DT_CHR &&
  191                     (de->de_cdp->cdp_flags & CDP_ACTIVE) == 0)
  192                         continue;
  193 
  194                 if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
  195                         continue;
  196                 break;
  197         }
  198         KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
  199             ("devfs_find: returning a doomed entry"));
  200         return (de);
  201 }
  202 
  203 struct devfs_dirent *
  204 devfs_newdirent(char *name, int namelen)
  205 {
  206         int i;
  207         struct devfs_dirent *de;
  208         struct dirent d;
  209 
  210         d.d_namlen = namelen;
  211         i = sizeof (*de) + GENERIC_DIRSIZ(&d); 
  212         de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
  213         de->de_dirent = (struct dirent *)(de + 1);
  214         de->de_dirent->d_namlen = namelen;
  215         de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
  216         bcopy(name, de->de_dirent->d_name, namelen);
  217         de->de_dirent->d_name[namelen] = '\0';
  218         vfs_timestamp(&de->de_ctime);
  219         de->de_mtime = de->de_atime = de->de_ctime;
  220         de->de_links = 1;
  221         de->de_holdcnt = 1;
  222 #ifdef MAC
  223         mac_devfs_init(de);
  224 #endif
  225         return (de);
  226 }
  227 
  228 struct devfs_dirent *
  229 devfs_parent_dirent(struct devfs_dirent *de)
  230 {
  231 
  232         if (de->de_dirent->d_type != DT_DIR)
  233                 return (de->de_dir);
  234 
  235         if (de->de_flags & (DE_DOT | DE_DOTDOT))
  236                 return (NULL);
  237 
  238         de = TAILQ_FIRST(&de->de_dlist);        /* "." */
  239         if (de == NULL)
  240                 return (NULL);
  241         de = TAILQ_NEXT(de, de_list);           /* ".." */
  242         if (de == NULL)
  243                 return (NULL);
  244 
  245         return (de->de_dir);
  246 }
  247 
  248 struct devfs_dirent *
  249 devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode)
  250 {
  251         struct devfs_dirent *dd;
  252         struct devfs_dirent *de;
  253 
  254         /* Create the new directory */
  255         dd = devfs_newdirent(name, namelen);
  256         TAILQ_INIT(&dd->de_dlist);
  257         dd->de_dirent->d_type = DT_DIR;
  258         dd->de_mode = 0555;
  259         dd->de_links = 2;
  260         dd->de_dir = dd;
  261         if (inode != 0)
  262                 dd->de_inode = inode;
  263         else
  264                 dd->de_inode = alloc_unr(devfs_inos);
  265 
  266         /*
  267          * "." and ".." are always the two first entries in the
  268          * de_dlist list.
  269          *
  270          * Create the "." entry in the new directory.
  271          */
  272         de = devfs_newdirent(".", 1);
  273         de->de_dirent->d_type = DT_DIR;
  274         de->de_flags |= DE_DOT;
  275         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  276         de->de_dir = dd;
  277 
  278         /* Create the ".." entry in the new directory. */
  279         de = devfs_newdirent("..", 2);
  280         de->de_dirent->d_type = DT_DIR;
  281         de->de_flags |= DE_DOTDOT;
  282         TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  283         if (dotdot == NULL) {
  284                 de->de_dir = dd;
  285         } else {
  286                 de->de_dir = dotdot;
  287                 sx_assert(&dmp->dm_lock, SX_XLOCKED);
  288                 TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
  289                 dotdot->de_links++;
  290                 devfs_rules_apply(dmp, dd);
  291         }
  292 
  293 #ifdef MAC
  294         mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
  295 #endif
  296         return (dd);
  297 }
  298 
  299 void
  300 devfs_dirent_free(struct devfs_dirent *de)
  301 {
  302         struct vnode *vp;
  303 
  304         vp = de->de_vnode;
  305         mtx_lock(&devfs_de_interlock);
  306         if (vp != NULL && vp->v_data == de)
  307                 vp->v_data = NULL;
  308         mtx_unlock(&devfs_de_interlock);
  309         free(de, M_DEVFS3);
  310 }
  311 
  312 /*
  313  * Removes a directory if it is empty. Also empty parent directories are
  314  * removed recursively.
  315  */
  316 static void
  317 devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
  318 {
  319         struct devfs_dirent *dd, *de_dot, *de_dotdot;
  320 
  321         sx_assert(&dm->dm_lock, SX_XLOCKED);
  322 
  323         for (;;) {
  324                 KASSERT(de->de_dirent->d_type == DT_DIR,
  325                     ("devfs_rmdir_empty: de is not a directory"));
  326 
  327                 if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
  328                         return;
  329 
  330                 de_dot = TAILQ_FIRST(&de->de_dlist);
  331                 KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
  332                 de_dotdot = TAILQ_NEXT(de_dot, de_list);
  333                 KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
  334                 /* Return if the directory is not empty. */
  335                 if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
  336                         return;
  337 
  338                 dd = devfs_parent_dirent(de);
  339                 KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
  340                 TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
  341                 TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
  342                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  343                 DEVFS_DE_HOLD(dd);
  344                 devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  345                 devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
  346                 devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
  347                 if (DEVFS_DE_DROP(dd)) {
  348                         devfs_dirent_free(dd);
  349                         return;
  350                 }
  351 
  352                 de = dd;
  353         }
  354 }
  355 
  356 /*
  357  * The caller needs to hold the dm for the duration of the call since
  358  * dm->dm_lock may be temporary dropped.
  359  */
  360 void
  361 devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
  362 {
  363         struct devfs_dirent *dd;
  364         struct vnode *vp;
  365 
  366         KASSERT((de->de_flags & DE_DOOMED) == 0,
  367                 ("devfs_delete doomed dirent"));
  368         de->de_flags |= DE_DOOMED;
  369 
  370         if ((flags & DEVFS_DEL_NORECURSE) == 0) {
  371                 dd = devfs_parent_dirent(de);
  372                 if (dd != NULL)
  373                         DEVFS_DE_HOLD(dd);
  374                 if (de->de_flags & DE_USER) {
  375                         KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
  376                         devfs_dir_unref_de(dm, dd);
  377                 }
  378         } else
  379                 dd = NULL;
  380 
  381         mtx_lock(&devfs_de_interlock);
  382         vp = de->de_vnode;
  383         if (vp != NULL) {
  384                 VI_LOCK(vp);
  385                 mtx_unlock(&devfs_de_interlock);
  386                 vholdl(vp);
  387                 sx_unlock(&dm->dm_lock);
  388                 if ((flags & DEVFS_DEL_VNLOCKED) == 0)
  389                         vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
  390                 else
  391                         VI_UNLOCK(vp);
  392                 vgone(vp);
  393                 if ((flags & DEVFS_DEL_VNLOCKED) == 0)
  394                         VOP_UNLOCK(vp, 0);
  395                 vdrop(vp);
  396                 sx_xlock(&dm->dm_lock);
  397         } else
  398                 mtx_unlock(&devfs_de_interlock);
  399         if (de->de_symlink) {
  400                 free(de->de_symlink, M_DEVFS);
  401                 de->de_symlink = NULL;
  402         }
  403 #ifdef MAC
  404         mac_devfs_destroy(de);
  405 #endif
  406         if (de->de_inode > DEVFS_ROOTINO) {
  407                 devfs_free_cdp_inode(de->de_inode);
  408                 de->de_inode = 0;
  409         }
  410         if (DEVFS_DE_DROP(de))
  411                 devfs_dirent_free(de);
  412 
  413         if (dd != NULL) {
  414                 if (DEVFS_DE_DROP(dd))
  415                         devfs_dirent_free(dd);
  416                 else
  417                         devfs_rmdir_empty(dm, dd);
  418         }
  419 }
  420 
  421 /*
  422  * Called on unmount.
  423  * Recursively removes the entire tree.
  424  * The caller needs to hold the dm for the duration of the call.
  425  */
  426 
  427 static void
  428 devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
  429 {
  430         struct devfs_dirent *de;
  431 
  432         sx_assert(&dm->dm_lock, SX_XLOCKED);
  433 
  434         DEVFS_DE_HOLD(dd);
  435         for (;;) {
  436                 /*
  437                  * Use TAILQ_LAST() to remove "." and ".." last.
  438                  * We might need ".." to resolve a path in
  439                  * devfs_dir_unref_de().
  440                  */
  441                 de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
  442                 if (de == NULL)
  443                         break;
  444                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
  445                 if (de->de_flags & DE_USER)
  446                         devfs_dir_unref_de(dm, dd);
  447                 if (de->de_flags & (DE_DOT | DE_DOTDOT))
  448                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  449                 else if (de->de_dirent->d_type == DT_DIR)
  450                         devfs_purge(dm, de);
  451                 else
  452                         devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
  453         }
  454         if (DEVFS_DE_DROP(dd))
  455                 devfs_dirent_free(dd);
  456         else if ((dd->de_flags & DE_DOOMED) == 0)
  457                 devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
  458 }
  459 
  460 /*
  461  * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
  462  * by the mount points dm_idx.
  463  * This function extends the array when necessary, taking into account that
  464  * the default array is 1 element and not malloc'ed.
  465  */
  466 static void
  467 devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
  468 {
  469         struct devfs_dirent **dep;
  470         int siz;
  471 
  472         siz = (dm->dm_idx + 1) * sizeof *dep;
  473         dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
  474         dev_lock();
  475         if (dm->dm_idx <= cdp->cdp_maxdirent) {
  476                 /* We got raced */
  477                 dev_unlock();
  478                 free(dep, M_DEVFS2);
  479                 return;
  480         } 
  481         memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
  482         if (cdp->cdp_maxdirent > 0)
  483                 free(cdp->cdp_dirents, M_DEVFS2);
  484         cdp->cdp_dirents = dep;
  485         /*
  486          * XXX: if malloc told us how much we actually got this could
  487          * XXX: be optimized.
  488          */
  489         cdp->cdp_maxdirent = dm->dm_idx;
  490         dev_unlock();
  491 }
  492 
  493 /*
  494  * The caller needs to hold the dm for the duration of the call.
  495  */
  496 static int
  497 devfs_populate_loop(struct devfs_mount *dm, int cleanup)
  498 {
  499         struct cdev_priv *cdp;
  500         struct devfs_dirent *de;
  501         struct devfs_dirent *dd, *dt;
  502         struct cdev *pdev;
  503         int de_flags, depth, j;
  504         char *q, *s;
  505 
  506         sx_assert(&dm->dm_lock, SX_XLOCKED);
  507         dev_lock();
  508         TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
  509 
  510                 KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
  511 
  512                 /*
  513                  * If we are unmounting, or the device has been destroyed,
  514                  * clean up our dirent.
  515                  */
  516                 if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
  517                     dm->dm_idx <= cdp->cdp_maxdirent &&
  518                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  519                         de = cdp->cdp_dirents[dm->dm_idx];
  520                         cdp->cdp_dirents[dm->dm_idx] = NULL;
  521                         KASSERT(cdp == de->de_cdp,
  522                             ("%s %d %s %p %p", __func__, __LINE__,
  523                             cdp->cdp_c.si_name, cdp, de->de_cdp));
  524                         KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
  525                         dev_unlock();
  526 
  527                         TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
  528                         de->de_cdp = NULL;
  529                         de->de_inode = 0;
  530                         devfs_delete(dm, de, 0);
  531                         dev_lock();
  532                         cdp->cdp_inuse--;
  533                         dev_unlock();
  534                         return (1);
  535                 }
  536                 /*
  537                  * GC any lingering devices
  538                  */
  539                 if (!(cdp->cdp_flags & CDP_ACTIVE)) {
  540                         if (cdp->cdp_inuse > 0)
  541                                 continue;
  542                         TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
  543                         dev_unlock();
  544                         dev_rel(&cdp->cdp_c);
  545                         return (1);
  546                 }
  547                 /*
  548                  * Don't create any new dirents if we are unmounting
  549                  */
  550                 if (cleanup)
  551                         continue;
  552                 KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
  553 
  554                 if (dm->dm_idx <= cdp->cdp_maxdirent &&
  555                     cdp->cdp_dirents[dm->dm_idx] != NULL) {
  556                         de = cdp->cdp_dirents[dm->dm_idx];
  557                         KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
  558                         continue;
  559                 }
  560 
  561 
  562                 cdp->cdp_inuse++;
  563                 dev_unlock();
  564 
  565                 if (dm->dm_idx > cdp->cdp_maxdirent)
  566                         devfs_metoo(cdp, dm);
  567 
  568                 dd = dm->dm_rootdir;
  569                 s = cdp->cdp_c.si_name;
  570                 for (;;) {
  571                         for (q = s; *q != '/' && *q != '\0'; q++)
  572                                 continue;
  573                         if (*q != '/')
  574                                 break;
  575                         de = devfs_find(dd, s, q - s, 0);
  576                         if (de == NULL)
  577                                 de = devfs_vmkdir(dm, s, q - s, dd, 0);
  578                         else if (de->de_dirent->d_type == DT_LNK) {
  579                                 de = devfs_find(dd, s, q - s, DT_DIR);
  580                                 if (de == NULL)
  581                                         de = devfs_vmkdir(dm, s, q - s, dd, 0);
  582                                 de->de_flags |= DE_COVERED;
  583                         }
  584                         s = q + 1;
  585                         dd = de;
  586                         KASSERT(dd->de_dirent->d_type == DT_DIR &&
  587                             (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
  588                             ("%s: invalid directory (si_name=%s)",
  589                             __func__, cdp->cdp_c.si_name));
  590 
  591                 }
  592                 de_flags = 0;
  593                 de = devfs_find(dd, s, q - s, DT_LNK);
  594                 if (de != NULL)
  595                         de_flags |= DE_COVERED;
  596 
  597                 de = devfs_newdirent(s, q - s);
  598                 if (cdp->cdp_c.si_flags & SI_ALIAS) {
  599                         de->de_uid = 0;
  600                         de->de_gid = 0;
  601                         de->de_mode = 0755;
  602                         de->de_dirent->d_type = DT_LNK;
  603                         pdev = cdp->cdp_c.si_parent;
  604                         dt = dd;
  605                         depth = 0;
  606                         while (dt != dm->dm_rootdir &&
  607                             (dt = devfs_parent_dirent(dt)) != NULL)
  608                                 depth++;
  609                         j = depth * 3 + strlen(pdev->si_name) + 1;
  610                         de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
  611                         de->de_symlink[0] = 0;
  612                         while (depth-- > 0)
  613                                 strcat(de->de_symlink, "../");
  614                         strcat(de->de_symlink, pdev->si_name);
  615                 } else {
  616                         de->de_uid = cdp->cdp_c.si_uid;
  617                         de->de_gid = cdp->cdp_c.si_gid;
  618                         de->de_mode = cdp->cdp_c.si_mode;
  619                         de->de_dirent->d_type = DT_CHR;
  620                 }
  621                 de->de_flags |= de_flags;
  622                 de->de_inode = cdp->cdp_inode;
  623                 de->de_cdp = cdp;
  624 #ifdef MAC
  625                 mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
  626                     &cdp->cdp_c, de);
  627 #endif
  628                 de->de_dir = dd;
  629                 TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
  630                 devfs_rules_apply(dm, de);
  631                 dev_lock();
  632                 /* XXX: could check that cdp is still active here */
  633                 KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
  634                     ("%s %d\n", __func__, __LINE__));
  635                 cdp->cdp_dirents[dm->dm_idx] = de;
  636                 KASSERT(de->de_cdp != (void *)0xdeadc0de,
  637                     ("%s %d\n", __func__, __LINE__));
  638                 dev_unlock();
  639                 return (1);
  640         }
  641         dev_unlock();
  642         return (0);
  643 }
  644 
  645 /*
  646  * The caller needs to hold the dm for the duration of the call.
  647  */
  648 void
  649 devfs_populate(struct devfs_mount *dm)
  650 {
  651         unsigned gen;
  652 
  653         sx_assert(&dm->dm_lock, SX_XLOCKED);
  654         gen = devfs_generation;
  655         if (dm->dm_generation == gen)
  656                 return;
  657         while (devfs_populate_loop(dm, 0))
  658                 continue;
  659         dm->dm_generation = gen;
  660 }
  661 
  662 /*
  663  * The caller needs to hold the dm for the duration of the call.
  664  */
  665 void
  666 devfs_cleanup(struct devfs_mount *dm)
  667 {
  668 
  669         sx_assert(&dm->dm_lock, SX_XLOCKED);
  670         while (devfs_populate_loop(dm, 1))
  671                 continue;
  672         devfs_purge(dm, dm->dm_rootdir);
  673 }
  674 
  675 /*
  676  * devfs_create() and devfs_destroy() are called from kern_conf.c and
  677  * in both cases the devlock() mutex is held, so no further locking
  678  * is necessary and no sleeping allowed.
  679  */
  680 
  681 void
  682 devfs_create(struct cdev *dev)
  683 {
  684         struct cdev_priv *cdp;
  685 
  686         mtx_assert(&devmtx, MA_OWNED);
  687         cdp = cdev2priv(dev);
  688         cdp->cdp_flags |= CDP_ACTIVE;
  689         cdp->cdp_inode = alloc_unrl(devfs_inos);
  690         dev_refl(dev);
  691         TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
  692         devfs_generation++;
  693 }
  694 
  695 void
  696 devfs_destroy(struct cdev *dev)
  697 {
  698         struct cdev_priv *cdp;
  699 
  700         mtx_assert(&devmtx, MA_OWNED);
  701         cdp = cdev2priv(dev);
  702         cdp->cdp_flags &= ~CDP_ACTIVE;
  703         devfs_generation++;
  704 }
  705 
  706 ino_t
  707 devfs_alloc_cdp_inode(void)
  708 {
  709 
  710         return (alloc_unr(devfs_inos));
  711 }
  712 
  713 void
  714 devfs_free_cdp_inode(ino_t ino)
  715 {
  716 
  717         if (ino > 0)
  718                 free_unr(devfs_inos, ino);
  719 }
  720 
  721 static void
  722 devfs_devs_init(void *junk __unused)
  723 {
  724 
  725         devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
  726 }
  727 
  728 SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);

Cache object: 878edad718b3ec7a3de9f3c59054fb4a


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