devfs_vnops.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  * Copyright (c) 1989, 1992-1993, 1995
    7  *      The Regents of the University of California.  All rights reserved.
    8  *
    9  * This code is derived from software donated to Berkeley by
   10  * Jan-Simon Pendry.
   11  *
   12  * Redistribution and use in source and binary forms, with or without
   13  * modification, are permitted provided that the following conditions
   14  * are met:
   15  * 1. Redistributions of source code must retain the above copyright
   16  *    notice, this list of conditions and the following disclaimer.
   17  * 2. Neither the name of the University nor the names of its contributors
   18  *    may be used to endorse or promote products derived from this software
   19  *    without specific prior written permission.
   20  *
   21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31  * SUCH DAMAGE.
   32  *
   33  *      @(#)kernfs_vnops.c      8.15 (Berkeley) 5/21/95
   34  * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vnops.c 1.43
   35  *
   36  * $FreeBSD$
   37  */
   38 
   39 /*
   40  * TODO:
   41  *      mkdir: want it ?
   42  */
   43 
   44 #include <sys/param.h>
   45 #include <sys/systm.h>
   46 #include <sys/conf.h>
   47 #include <sys/dirent.h>
   48 #include <sys/eventhandler.h>
   49 #include <sys/fcntl.h>
   50 #include <sys/file.h>
   51 #include <sys/filedesc.h>
   52 #include <sys/filio.h>
   53 #include <sys/jail.h>
   54 #include <sys/kernel.h>
   55 #include <sys/limits.h>
   56 #include <sys/lock.h>
   57 #include <sys/malloc.h>
   58 #include <sys/mman.h>
   59 #include <sys/mount.h>
   60 #include <sys/namei.h>
   61 #include <sys/priv.h>
   62 #include <sys/proc.h>
   63 #include <sys/stat.h>
   64 #include <sys/sx.h>
   65 #include <sys/sysctl.h>
   66 #include <sys/time.h>
   67 #include <sys/ttycom.h>
   68 #include <sys/unistd.h>
   69 #include <sys/vnode.h>
   70 
   71 static struct vop_vector devfs_vnodeops;
   72 static struct vop_vector devfs_specops;
   73 static struct fileops devfs_ops_f;
   74 
   75 #include <fs/devfs/devfs.h>
   76 #include <fs/devfs/devfs_int.h>
   77 
   78 #include <security/mac/mac_framework.h>
   79 
   80 #include <vm/vm.h>
   81 #include <vm/vm_extern.h>
   82 #include <vm/vm_object.h>
   83 
   84 static MALLOC_DEFINE(M_CDEVPDATA, "DEVFSP", "Metainfo for cdev-fp data");
   85 
   86 struct mtx      devfs_de_interlock;
   87 MTX_SYSINIT(devfs_de_interlock, &devfs_de_interlock, "devfs interlock", MTX_DEF);
   88 struct sx       clone_drain_lock;
   89 SX_SYSINIT(clone_drain_lock, &clone_drain_lock, "clone events drain lock");
   90 struct mtx      cdevpriv_mtx;
   91 MTX_SYSINIT(cdevpriv_mtx, &cdevpriv_mtx, "cdevpriv lock", MTX_DEF);
   92 
   93 SYSCTL_DECL(_vfs_devfs);
   94 
   95 static int devfs_dotimes;
   96 SYSCTL_INT(_vfs_devfs, OID_AUTO, dotimes, CTLFLAG_RW,
   97     &devfs_dotimes, 0, "Update timestamps on DEVFS with default precision");
   98 
   99 /*
  100  * Update devfs node timestamp.  Note that updates are unlocked and
  101  * stat(2) could see partially updated times.
  102  */
  103 static void
  104 devfs_timestamp(struct timespec *tsp)
  105 {
  106         time_t ts;
  107 
  108         if (devfs_dotimes) {
  109                 vfs_timestamp(tsp);
  110         } else {
  111                 ts = time_second;
  112                 if (tsp->tv_sec != ts) {
  113                         tsp->tv_sec = ts;
  114                         tsp->tv_nsec = 0;
  115                 }
  116         }
  117 }
  118 
  119 static int
  120 devfs_fp_check(struct file *fp, struct cdev **devp, struct cdevsw **dswp,
  121     int *ref)
  122 {
  123 
  124         *dswp = devvn_refthread(fp->f_vnode, devp, ref);
  125         if (*devp != fp->f_data) {
  126                 if (*dswp != NULL)
  127                         dev_relthread(*devp, *ref);
  128                 return (ENXIO);
  129         }
  130         KASSERT((*devp)->si_refcount > 0,
  131             ("devfs: un-referenced struct cdev *(%s)", devtoname(*devp)));
  132         if (*dswp == NULL)
  133                 return (ENXIO);
  134         curthread->td_fpop = fp;
  135         return (0);
  136 }
  137 
  138 int
  139 devfs_get_cdevpriv(void **datap)
  140 {
  141         struct file *fp;
  142         struct cdev_privdata *p;
  143         int error;
  144 
  145         fp = curthread->td_fpop;
  146         if (fp == NULL)
  147                 return (EBADF);
  148         p = fp->f_cdevpriv;
  149         if (p != NULL) {
  150                 error = 0;
  151                 *datap = p->cdpd_data;
  152         } else
  153                 error = ENOENT;
  154         return (error);
  155 }
  156 
  157 int
  158 devfs_set_cdevpriv(void *priv, d_priv_dtor_t *priv_dtr)
  159 {
  160         struct file *fp;
  161         struct cdev_priv *cdp;
  162         struct cdev_privdata *p;
  163         int error;
  164 
  165         fp = curthread->td_fpop;
  166         if (fp == NULL)
  167                 return (ENOENT);
  168         cdp = cdev2priv((struct cdev *)fp->f_data);
  169         p = malloc(sizeof(struct cdev_privdata), M_CDEVPDATA, M_WAITOK);
  170         p->cdpd_data = priv;
  171         p->cdpd_dtr = priv_dtr;
  172         p->cdpd_fp = fp;
  173         mtx_lock(&cdevpriv_mtx);
  174         if (fp->f_cdevpriv == NULL) {
  175                 LIST_INSERT_HEAD(&cdp->cdp_fdpriv, p, cdpd_list);
  176                 fp->f_cdevpriv = p;
  177                 mtx_unlock(&cdevpriv_mtx);
  178                 error = 0;
  179         } else {
  180                 mtx_unlock(&cdevpriv_mtx);
  181                 free(p, M_CDEVPDATA);
  182                 error = EBUSY;
  183         }
  184         return (error);
  185 }
  186 
  187 void
  188 devfs_destroy_cdevpriv(struct cdev_privdata *p)
  189 {
  190 
  191         mtx_assert(&cdevpriv_mtx, MA_OWNED);
  192         KASSERT(p->cdpd_fp->f_cdevpriv == p,
  193             ("devfs_destoy_cdevpriv %p != %p", p->cdpd_fp->f_cdevpriv, p));
  194         p->cdpd_fp->f_cdevpriv = NULL;
  195         LIST_REMOVE(p, cdpd_list);
  196         mtx_unlock(&cdevpriv_mtx);
  197         (p->cdpd_dtr)(p->cdpd_data);
  198         free(p, M_CDEVPDATA);
  199 }
  200 
  201 static void
  202 devfs_fpdrop(struct file *fp)
  203 {
  204         struct cdev_privdata *p;
  205 
  206         mtx_lock(&cdevpriv_mtx);
  207         if ((p = fp->f_cdevpriv) == NULL) {
  208                 mtx_unlock(&cdevpriv_mtx);
  209                 return;
  210         }
  211         devfs_destroy_cdevpriv(p);
  212 }
  213 
  214 void
  215 devfs_clear_cdevpriv(void)
  216 {
  217         struct file *fp;
  218 
  219         fp = curthread->td_fpop;
  220         if (fp == NULL)
  221                 return;
  222         devfs_fpdrop(fp);
  223 }
  224 
  225 static void
  226 devfs_usecount_add(struct vnode *vp)
  227 {
  228         struct devfs_dirent *de;
  229         struct cdev *dev;
  230 
  231         mtx_lock(&devfs_de_interlock);
  232         VI_LOCK(vp);
  233         VNPASS(vp->v_type == VCHR || vp->v_type == VBAD, vp);
  234         if (VN_IS_DOOMED(vp)) {
  235                 goto out_unlock;
  236         }
  237 
  238         de = vp->v_data;
  239         dev = vp->v_rdev;
  240         MPASS(de != NULL);
  241         MPASS(dev != NULL);
  242         dev->si_usecount++;
  243         de->de_usecount++;
  244 out_unlock:
  245         VI_UNLOCK(vp);
  246         mtx_unlock(&devfs_de_interlock);
  247 }
  248 
  249 static void
  250 devfs_usecount_subl(struct vnode *vp)
  251 {
  252         struct devfs_dirent *de;
  253         struct cdev *dev;
  254 
  255         mtx_assert(&devfs_de_interlock, MA_OWNED);
  256         ASSERT_VI_LOCKED(vp, __func__);
  257         VNPASS(vp->v_type == VCHR || vp->v_type == VBAD, vp);
  258 
  259         de = vp->v_data;
  260         dev = vp->v_rdev;
  261         if (de == NULL)
  262                 return;
  263         if (dev == NULL) {
  264                 MPASS(de->de_usecount == 0);
  265                 return;
  266         }
  267         if (dev->si_usecount < de->de_usecount)
  268                 panic("%s: si_usecount underflow for dev %p "
  269                     "(has %ld, dirent has %d)\n",
  270                     __func__, dev, dev->si_usecount, de->de_usecount);
  271         if (VN_IS_DOOMED(vp)) {
  272                 dev->si_usecount -= de->de_usecount;
  273                 de->de_usecount = 0;
  274         } else {
  275                 if (de->de_usecount == 0)
  276                         panic("%s: de_usecount underflow for dev %p\n",
  277                             __func__, dev);
  278                 dev->si_usecount--;
  279                 de->de_usecount--;
  280         }
  281 }
  282 
  283 static void
  284 devfs_usecount_sub(struct vnode *vp)
  285 {
  286 
  287         mtx_lock(&devfs_de_interlock);
  288         VI_LOCK(vp);
  289         devfs_usecount_subl(vp);
  290         VI_UNLOCK(vp);
  291         mtx_unlock(&devfs_de_interlock);
  292 }
  293 
  294 static int
  295 devfs_usecountl(struct vnode *vp)
  296 {
  297 
  298         VNPASS(vp->v_type == VCHR, vp);
  299         mtx_assert(&devfs_de_interlock, MA_OWNED);
  300         ASSERT_VI_LOCKED(vp, __func__);
  301         return (vp->v_rdev->si_usecount);
  302 }
  303 
  304 int
  305 devfs_usecount(struct vnode *vp)
  306 {
  307         int count;
  308 
  309         VNPASS(vp->v_type == VCHR, vp);
  310         mtx_lock(&devfs_de_interlock);
  311         VI_LOCK(vp);
  312         count = devfs_usecountl(vp);
  313         VI_UNLOCK(vp);
  314         mtx_unlock(&devfs_de_interlock);
  315         return (count);
  316 }
  317 
  318 void
  319 devfs_ctty_ref(struct vnode *vp)
  320 {
  321 
  322         vrefact(vp);
  323         devfs_usecount_add(vp);
  324 }
  325 
  326 void
  327 devfs_ctty_unref(struct vnode *vp)
  328 {
  329 
  330         devfs_usecount_sub(vp);
  331         vrele(vp);
  332 }
  333 
  334 /*
  335  * On success devfs_populate_vp() returns with dmp->dm_lock held.
  336  */
  337 static int
  338 devfs_populate_vp(struct vnode *vp)
  339 {
  340         struct devfs_dirent *de;
  341         struct devfs_mount *dmp;
  342         int locked;
  343 
  344         ASSERT_VOP_LOCKED(vp, "devfs_populate_vp");
  345 
  346         dmp = VFSTODEVFS(vp->v_mount);
  347         if (!devfs_populate_needed(dmp)) {
  348                 sx_xlock(&dmp->dm_lock);
  349                 goto out_nopopulate;
  350         }
  351 
  352         locked = VOP_ISLOCKED(vp);
  353 
  354         sx_xlock(&dmp->dm_lock);
  355         DEVFS_DMP_HOLD(dmp);
  356 
  357         /* Can't call devfs_populate() with the vnode lock held. */
  358         VOP_UNLOCK(vp);
  359         devfs_populate(dmp);
  360 
  361         sx_xunlock(&dmp->dm_lock);
  362         vn_lock(vp, locked | LK_RETRY);
  363         sx_xlock(&dmp->dm_lock);
  364         if (DEVFS_DMP_DROP(dmp)) {
  365                 sx_xunlock(&dmp->dm_lock);
  366                 devfs_unmount_final(dmp);
  367                 return (ERESTART);
  368         }
  369 out_nopopulate:
  370         if (VN_IS_DOOMED(vp)) {
  371                 sx_xunlock(&dmp->dm_lock);
  372                 return (ERESTART);
  373         }
  374         de = vp->v_data;
  375         KASSERT(de != NULL,
  376             ("devfs_populate_vp: vp->v_data == NULL but vnode not doomed"));
  377         if ((de->de_flags & DE_DOOMED) != 0) {
  378                 sx_xunlock(&dmp->dm_lock);
  379                 return (ERESTART);
  380         }
  381 
  382         return (0);
  383 }
  384 
  385 static int
  386 devfs_vptocnp(struct vop_vptocnp_args *ap)
  387 {
  388         struct vnode *vp = ap->a_vp;
  389         struct vnode **dvp = ap->a_vpp;
  390         struct devfs_mount *dmp;
  391         char *buf = ap->a_buf;
  392         size_t *buflen = ap->a_buflen;
  393         struct devfs_dirent *dd, *de;
  394         int i, error;
  395 
  396         dmp = VFSTODEVFS(vp->v_mount);
  397 
  398         error = devfs_populate_vp(vp);
  399         if (error != 0)
  400                 return (error);
  401 
  402         if (vp->v_type != VCHR && vp->v_type != VDIR) {
  403                 error = ENOENT;
  404                 goto finished;
  405         }
  406 
  407         dd = vp->v_data;
  408         if (vp->v_type == VDIR && dd == dmp->dm_rootdir) {
  409                 *dvp = vp;
  410                 vref(*dvp);
  411                 goto finished;
  412         }
  413 
  414         i = *buflen;
  415         i -= dd->de_dirent->d_namlen;
  416         if (i < 0) {
  417                 error = ENOMEM;
  418                 goto finished;
  419         }
  420         bcopy(dd->de_dirent->d_name, buf + i, dd->de_dirent->d_namlen);
  421         *buflen = i;
  422         de = devfs_parent_dirent(dd);
  423         if (de == NULL) {
  424                 error = ENOENT;
  425                 goto finished;
  426         }
  427         mtx_lock(&devfs_de_interlock);
  428         *dvp = de->de_vnode;
  429         if (*dvp != NULL) {
  430                 VI_LOCK(*dvp);
  431                 mtx_unlock(&devfs_de_interlock);
  432                 vholdl(*dvp);
  433                 VI_UNLOCK(*dvp);
  434                 vref(*dvp);
  435                 vdrop(*dvp);
  436         } else {
  437                 mtx_unlock(&devfs_de_interlock);
  438                 error = ENOENT;
  439         }
  440 finished:
  441         sx_xunlock(&dmp->dm_lock);
  442         return (error);
  443 }
  444 
  445 /*
  446  * Construct the fully qualified path name relative to the mountpoint.
  447  * If a NULL cnp is provided, no '/' is appended to the resulting path.
  448  */
  449 char *
  450 devfs_fqpn(char *buf, struct devfs_mount *dmp, struct devfs_dirent *dd,
  451     struct componentname *cnp)
  452 {
  453         int i;
  454         struct devfs_dirent *de;
  455 
  456         sx_assert(&dmp->dm_lock, SA_LOCKED);
  457 
  458         i = SPECNAMELEN;
  459         buf[i] = '\0';
  460         if (cnp != NULL)
  461                 i -= cnp->cn_namelen;
  462         if (i < 0)
  463                  return (NULL);
  464         if (cnp != NULL)
  465                 bcopy(cnp->cn_nameptr, buf + i, cnp->cn_namelen);
  466         de = dd;
  467         while (de != dmp->dm_rootdir) {
  468                 if (cnp != NULL || i < SPECNAMELEN) {
  469                         i--;
  470                         if (i < 0)
  471                                  return (NULL);
  472                         buf[i] = '/';
  473                 }
  474                 i -= de->de_dirent->d_namlen;
  475                 if (i < 0)
  476                          return (NULL);
  477                 bcopy(de->de_dirent->d_name, buf + i,
  478                     de->de_dirent->d_namlen);
  479                 de = devfs_parent_dirent(de);
  480                 if (de == NULL)
  481                         return (NULL);
  482         }
  483         return (buf + i);
  484 }
  485 
  486 static int
  487 devfs_allocv_drop_refs(int drop_dm_lock, struct devfs_mount *dmp,
  488         struct devfs_dirent *de)
  489 {
  490         int not_found;
  491 
  492         not_found = 0;
  493         if (de->de_flags & DE_DOOMED)
  494                 not_found = 1;
  495         if (DEVFS_DE_DROP(de)) {
  496                 KASSERT(not_found == 1, ("DEVFS de dropped but not doomed"));
  497                 devfs_dirent_free(de);
  498         }
  499         if (DEVFS_DMP_DROP(dmp)) {
  500                 KASSERT(not_found == 1,
  501                         ("DEVFS mount struct freed before dirent"));
  502                 not_found = 2;
  503                 sx_xunlock(&dmp->dm_lock);
  504                 devfs_unmount_final(dmp);
  505         }
  506         if (not_found == 1 || (drop_dm_lock && not_found != 2))
  507                 sx_unlock(&dmp->dm_lock);
  508         return (not_found);
  509 }
  510 
  511 static void
  512 devfs_insmntque_dtr(struct vnode *vp, void *arg)
  513 {
  514         struct devfs_dirent *de;
  515 
  516         de = (struct devfs_dirent *)arg;
  517         mtx_lock(&devfs_de_interlock);
  518         vp->v_data = NULL;
  519         de->de_vnode = NULL;
  520         mtx_unlock(&devfs_de_interlock);
  521         vgone(vp);
  522         vput(vp);
  523 }
  524 
  525 /*
  526  * devfs_allocv shall be entered with dmp->dm_lock held, and it drops
  527  * it on return.
  528  */
  529 int
  530 devfs_allocv(struct devfs_dirent *de, struct mount *mp, int lockmode,
  531     struct vnode **vpp)
  532 {
  533         int error;
  534         struct vnode *vp;
  535         struct cdev *dev;
  536         struct devfs_mount *dmp;
  537         struct cdevsw *dsw;
  538         enum vgetstate vs;
  539 
  540         dmp = VFSTODEVFS(mp);
  541         if (de->de_flags & DE_DOOMED) {
  542                 sx_xunlock(&dmp->dm_lock);
  543                 return (ENOENT);
  544         }
  545 loop:
  546         DEVFS_DE_HOLD(de);
  547         DEVFS_DMP_HOLD(dmp);
  548         mtx_lock(&devfs_de_interlock);
  549         vp = de->de_vnode;
  550         if (vp != NULL) {
  551                 vs = vget_prep(vp);
  552                 mtx_unlock(&devfs_de_interlock);
  553                 sx_xunlock(&dmp->dm_lock);
  554                 vget_finish(vp, lockmode | LK_RETRY, vs);
  555                 sx_xlock(&dmp->dm_lock);
  556                 if (devfs_allocv_drop_refs(0, dmp, de)) {
  557                         vput(vp);
  558                         return (ENOENT);
  559                 }
  560                 else if (VN_IS_DOOMED(vp)) {
  561                         mtx_lock(&devfs_de_interlock);
  562                         if (de->de_vnode == vp) {
  563                                 de->de_vnode = NULL;
  564                                 vp->v_data = NULL;
  565                         }
  566                         mtx_unlock(&devfs_de_interlock);
  567                         vput(vp);
  568                         goto loop;
  569                 }
  570                 sx_xunlock(&dmp->dm_lock);
  571                 *vpp = vp;
  572                 return (0);
  573         }
  574         mtx_unlock(&devfs_de_interlock);
  575         if (de->de_dirent->d_type == DT_CHR) {
  576                 if (!(de->de_cdp->cdp_flags & CDP_ACTIVE)) {
  577                         devfs_allocv_drop_refs(1, dmp, de);
  578                         return (ENOENT);
  579                 }
  580                 dev = &de->de_cdp->cdp_c;
  581         } else {
  582                 dev = NULL;
  583         }
  584         error = getnewvnode("devfs", mp, &devfs_vnodeops, &vp);
  585         if (error != 0) {
  586                 devfs_allocv_drop_refs(1, dmp, de);
  587                 printf("devfs_allocv: failed to allocate new vnode\n");
  588                 return (error);
  589         }
  590 
  591         if (de->de_dirent->d_type == DT_CHR) {
  592                 vp->v_type = VCHR;
  593                 VI_LOCK(vp);
  594                 dev_lock();
  595                 dev_refl(dev);
  596                 /* XXX: v_rdev should be protect by vnode lock */
  597                 vp->v_rdev = dev;
  598                 VNPASS(vp->v_usecount == 1, vp);
  599                 /* Special casing of ttys for deadfs.  Probably redundant. */
  600                 dsw = dev->si_devsw;
  601                 if (dsw != NULL && (dsw->d_flags & D_TTY) != 0)
  602                         vp->v_vflag |= VV_ISTTY;
  603                 dev_unlock();
  604                 VI_UNLOCK(vp);
  605                 if ((dev->si_flags & SI_ETERNAL) != 0)
  606                         vp->v_vflag |= VV_ETERNALDEV;
  607                 vp->v_op = &devfs_specops;
  608         } else if (de->de_dirent->d_type == DT_DIR) {
  609                 vp->v_type = VDIR;
  610         } else if (de->de_dirent->d_type == DT_LNK) {
  611                 vp->v_type = VLNK;
  612         } else {
  613                 vp->v_type = VBAD;
  614         }
  615         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOWITNESS);
  616         VN_LOCK_ASHARE(vp);
  617         mtx_lock(&devfs_de_interlock);
  618         vp->v_data = de;
  619         de->de_vnode = vp;
  620         mtx_unlock(&devfs_de_interlock);
  621         error = insmntque1(vp, mp, devfs_insmntque_dtr, de);
  622         if (error != 0) {
  623                 (void) devfs_allocv_drop_refs(1, dmp, de);
  624                 return (error);
  625         }
  626         if (devfs_allocv_drop_refs(0, dmp, de)) {
  627                 vput(vp);
  628                 return (ENOENT);
  629         }
  630 #ifdef MAC
  631         mac_devfs_vnode_associate(mp, de, vp);
  632 #endif
  633         sx_xunlock(&dmp->dm_lock);
  634         *vpp = vp;
  635         return (0);
  636 }
  637 
  638 static int
  639 devfs_access(struct vop_access_args *ap)
  640 {
  641         struct vnode *vp = ap->a_vp;
  642         struct devfs_dirent *de;
  643         struct proc *p;
  644         int error;
  645 
  646         de = vp->v_data;
  647         if (vp->v_type == VDIR)
  648                 de = de->de_dir;
  649 
  650         error = vaccess(vp->v_type, de->de_mode, de->de_uid, de->de_gid,
  651             ap->a_accmode, ap->a_cred);
  652         if (error == 0)
  653                 return (0);
  654         if (error != EACCES)
  655                 return (error);
  656         p = ap->a_td->td_proc;
  657         /* We do, however, allow access to the controlling terminal */
  658         PROC_LOCK(p);
  659         if (!(p->p_flag & P_CONTROLT)) {
  660                 PROC_UNLOCK(p);
  661                 return (error);
  662         }
  663         if (p->p_session->s_ttydp == de->de_cdp)
  664                 error = 0;
  665         PROC_UNLOCK(p);
  666         return (error);
  667 }
  668 
  669 _Static_assert(((FMASK | FCNTLFLAGS) & (FLASTCLOSE | FREVOKE)) == 0,
  670     "devfs-only flag reuse failed");
  671 
  672 static int
  673 devfs_close(struct vop_close_args *ap)
  674 {
  675         struct vnode *vp = ap->a_vp, *oldvp;
  676         struct thread *td = ap->a_td;
  677         struct proc *p;
  678         struct cdev *dev = vp->v_rdev;
  679         struct cdevsw *dsw;
  680         struct devfs_dirent *de = vp->v_data;
  681         int dflags, error, ref, vp_locked;
  682 
  683         /*
  684          * XXX: Don't call d_close() if we were called because of
  685          * XXX: insmntque1() failure.
  686          */
  687         if (vp->v_data == NULL)
  688                 return (0);
  689 
  690         /*
  691          * Hack: a tty device that is a controlling terminal
  692          * has a reference from the session structure.
  693          * We cannot easily tell that a character device is
  694          * a controlling terminal, unless it is the closing
  695          * process' controlling terminal.  In that case,
  696          * if the reference count is 2 (this last descriptor
  697          * plus the session), release the reference from the session.
  698          */
  699         if (de->de_usecount == 2 && td != NULL) {
  700                 p = td->td_proc;
  701                 PROC_LOCK(p);
  702                 if (vp == p->p_session->s_ttyvp) {
  703                         PROC_UNLOCK(p);
  704                         oldvp = NULL;
  705                         sx_xlock(&proctree_lock);
  706                         if (vp == p->p_session->s_ttyvp) {
  707                                 SESS_LOCK(p->p_session);
  708                                 mtx_lock(&devfs_de_interlock);
  709                                 VI_LOCK(vp);
  710                                 if (devfs_usecountl(vp) == 2 && !VN_IS_DOOMED(vp)) {
  711                                         p->p_session->s_ttyvp = NULL;
  712                                         p->p_session->s_ttydp = NULL;
  713                                         oldvp = vp;
  714                                 }
  715                                 VI_UNLOCK(vp);
  716                                 mtx_unlock(&devfs_de_interlock);
  717                                 SESS_UNLOCK(p->p_session);
  718                         }
  719                         sx_xunlock(&proctree_lock);
  720                         if (oldvp != NULL)
  721                                 devfs_ctty_unref(oldvp);
  722                 } else
  723                         PROC_UNLOCK(p);
  724         }
  725         /*
  726          * We do not want to really close the device if it
  727          * is still in use unless we are trying to close it
  728          * forcibly. Since every use (buffer, vnode, swap, cmap)
  729          * holds a reference to the vnode, and because we mark
  730          * any other vnodes that alias this device, when the
  731          * sum of the reference counts on all the aliased
  732          * vnodes descends to one, we are on last close.
  733          */
  734         dsw = dev_refthread(dev, &ref);
  735         if (dsw == NULL)
  736                 return (ENXIO);
  737         dflags = 0;
  738         mtx_lock(&devfs_de_interlock);
  739         VI_LOCK(vp);
  740         if (devfs_usecountl(vp) == 1)
  741                 dflags |= FLASTCLOSE;
  742         devfs_usecount_subl(vp);
  743         mtx_unlock(&devfs_de_interlock);
  744         if (VN_IS_DOOMED(vp)) {
  745                 /* Forced close. */
  746                 dflags |= FREVOKE | FNONBLOCK;
  747         } else if (dsw->d_flags & D_TRACKCLOSE) {
  748                 /* Keep device updated on status. */
  749         } else if ((dflags & FLASTCLOSE) == 0) {
  750                 VI_UNLOCK(vp);
  751                 dev_relthread(dev, ref);
  752                 return (0);
  753         }
  754         vholdnz(vp);
  755         VI_UNLOCK(vp);
  756         vp_locked = VOP_ISLOCKED(vp);
  757         VOP_UNLOCK(vp);
  758         KASSERT(dev->si_refcount > 0,
  759             ("devfs_close() on un-referenced struct cdev *(%s)", devtoname(dev)));
  760         error = dsw->d_close(dev, ap->a_fflag | dflags, S_IFCHR, td);
  761         dev_relthread(dev, ref);
  762         vn_lock(vp, vp_locked | LK_RETRY);
  763         vdrop(vp);
  764         return (error);
  765 }
  766 
  767 static int
  768 devfs_close_f(struct file *fp, struct thread *td)
  769 {
  770         int error;
  771         struct file *fpop;
  772 
  773         /*
  774          * NB: td may be NULL if this descriptor is closed due to
  775          * garbage collection from a closed UNIX domain socket.
  776          */
  777         fpop = curthread->td_fpop;
  778         curthread->td_fpop = fp;
  779         error = vnops.fo_close(fp, td);
  780         curthread->td_fpop = fpop;
  781 
  782         /*
  783          * The f_cdevpriv cannot be assigned non-NULL value while we
  784          * are destroying the file.
  785          */
  786         if (fp->f_cdevpriv != NULL)
  787                 devfs_fpdrop(fp);
  788         return (error);
  789 }
  790 
  791 static int
  792 devfs_getattr(struct vop_getattr_args *ap)
  793 {
  794         struct vnode *vp = ap->a_vp;
  795         struct vattr *vap = ap->a_vap;
  796         struct devfs_dirent *de;
  797         struct devfs_mount *dmp;
  798         struct cdev *dev;
  799         struct timeval boottime;
  800         int error;
  801 
  802         error = devfs_populate_vp(vp);
  803         if (error != 0)
  804                 return (error);
  805 
  806         dmp = VFSTODEVFS(vp->v_mount);
  807         sx_xunlock(&dmp->dm_lock);
  808 
  809         de = vp->v_data;
  810         KASSERT(de != NULL, ("Null dirent in devfs_getattr vp=%p", vp));
  811         if (vp->v_type == VDIR) {
  812                 de = de->de_dir;
  813                 KASSERT(de != NULL,
  814                     ("Null dir dirent in devfs_getattr vp=%p", vp));
  815         }
  816         vap->va_uid = de->de_uid;
  817         vap->va_gid = de->de_gid;
  818         vap->va_mode = de->de_mode;
  819         if (vp->v_type == VLNK)
  820                 vap->va_size = strlen(de->de_symlink);
  821         else if (vp->v_type == VDIR)
  822                 vap->va_size = vap->va_bytes = DEV_BSIZE;
  823         else
  824                 vap->va_size = 0;
  825         if (vp->v_type != VDIR)
  826                 vap->va_bytes = 0;
  827         vap->va_blocksize = DEV_BSIZE;
  828         vap->va_type = vp->v_type;
  829 
  830         getboottime(&boottime);
  831 #define fix(aa)                                                 \
  832         do {                                                    \
  833                 if ((aa).tv_sec <= 3600) {                      \
  834                         (aa).tv_sec = boottime.tv_sec;          \
  835                         (aa).tv_nsec = boottime.tv_usec * 1000; \
  836                 }                                               \
  837         } while (0)
  838 
  839         if (vp->v_type != VCHR)  {
  840                 fix(de->de_atime);
  841                 vap->va_atime = de->de_atime;
  842                 fix(de->de_mtime);
  843                 vap->va_mtime = de->de_mtime;
  844                 fix(de->de_ctime);
  845                 vap->va_ctime = de->de_ctime;
  846         } else {
  847                 dev = vp->v_rdev;
  848                 fix(dev->si_atime);
  849                 vap->va_atime = dev->si_atime;
  850                 fix(dev->si_mtime);
  851                 vap->va_mtime = dev->si_mtime;
  852                 fix(dev->si_ctime);
  853                 vap->va_ctime = dev->si_ctime;
  854 
  855                 vap->va_rdev = cdev2priv(dev)->cdp_inode;
  856         }
  857         vap->va_gen = 0;
  858         vap->va_flags = 0;
  859         vap->va_filerev = 0;
  860         vap->va_nlink = de->de_links;
  861         vap->va_fileid = de->de_inode;
  862 
  863         return (error);
  864 }
  865 
  866 /* ARGSUSED */
  867 static int
  868 devfs_ioctl_f(struct file *fp, u_long com, void *data, struct ucred *cred, struct thread *td)
  869 {
  870         struct file *fpop;
  871         int error;
  872 
  873         fpop = td->td_fpop;
  874         td->td_fpop = fp;
  875         error = vnops.fo_ioctl(fp, com, data, cred, td);
  876         td->td_fpop = fpop;
  877         return (error);
  878 }
  879 
  880 void *
  881 fiodgname_buf_get_ptr(void *fgnp, u_long com)
  882 {
  883         union {
  884                 struct fiodgname_arg    fgn;
  885 #ifdef COMPAT_FREEBSD32
  886                 struct fiodgname_arg32  fgn32;
  887 #endif
  888         } *fgnup;
  889 
  890         fgnup = fgnp;
  891         switch (com) {
  892         case FIODGNAME:
  893                 return (fgnup->fgn.buf);
  894 #ifdef COMPAT_FREEBSD32
  895         case FIODGNAME_32:
  896                 return ((void *)(uintptr_t)fgnup->fgn32.buf);
  897 #endif
  898         default:
  899                 panic("Unhandled ioctl command %ld", com);
  900         }
  901 }
  902 
  903 static int
  904 devfs_ioctl(struct vop_ioctl_args *ap)
  905 {
  906         struct fiodgname_arg *fgn;
  907         struct vnode *vpold, *vp;
  908         struct cdevsw *dsw;
  909         struct thread *td;
  910         struct session *sess;
  911         struct cdev *dev;
  912         int error, ref, i;
  913         const char *p;
  914         u_long com;
  915 
  916         vp = ap->a_vp;
  917         com = ap->a_command;
  918         td = ap->a_td;
  919 
  920         dsw = devvn_refthread(vp, &dev, &ref);
  921         if (dsw == NULL)
  922                 return (ENXIO);
  923         KASSERT(dev->si_refcount > 0,
  924             ("devfs: un-referenced struct cdev *(%s)", devtoname(dev)));
  925 
  926         switch (com) {
  927         case FIODTYPE:
  928                 *(int *)ap->a_data = dsw->d_flags & D_TYPEMASK;
  929                 error = 0;
  930                 break;
  931         case FIODGNAME:
  932 #ifdef  COMPAT_FREEBSD32
  933         case FIODGNAME_32:
  934 #endif
  935                 fgn = ap->a_data;
  936                 p = devtoname(dev);
  937                 i = strlen(p) + 1;
  938                 if (i > fgn->len)
  939                         error = EINVAL;
  940                 else
  941                         error = copyout(p, fiodgname_buf_get_ptr(fgn, com), i);
  942                 break;
  943         default:
  944                 error = dsw->d_ioctl(dev, com, ap->a_data, ap->a_fflag, td);
  945         }
  946 
  947         dev_relthread(dev, ref);
  948         if (error == ENOIOCTL)
  949                 error = ENOTTY;
  950 
  951         if (error == 0 && com == TIOCSCTTY) {
  952                 /*
  953                  * Do nothing if reassigning same control tty, or if the
  954                  * control tty has already disappeared.  If it disappeared,
  955                  * it's because we were racing with TIOCNOTTY.  TIOCNOTTY
  956                  * already took care of releasing the old vnode and we have
  957                  * nothing left to do.
  958                  */
  959                 sx_slock(&proctree_lock);
  960                 sess = td->td_proc->p_session;
  961                 if (sess->s_ttyvp == vp || sess->s_ttyp == NULL) {
  962                         sx_sunlock(&proctree_lock);
  963                         return (0);
  964                 }
  965 
  966                 devfs_ctty_ref(vp);
  967                 SESS_LOCK(sess);
  968                 vpold = sess->s_ttyvp;
  969                 sess->s_ttyvp = vp;
  970                 sess->s_ttydp = cdev2priv(dev);
  971                 SESS_UNLOCK(sess);
  972 
  973                 sx_sunlock(&proctree_lock);
  974 
  975                 /* Get rid of reference to old control tty */
  976                 if (vpold)
  977                         devfs_ctty_unref(vpold);
  978         }
  979         return (error);
  980 }
  981 
  982 /* ARGSUSED */
  983 static int
  984 devfs_kqfilter_f(struct file *fp, struct knote *kn)
  985 {
  986         struct cdev *dev;
  987         struct cdevsw *dsw;
  988         int error, ref;
  989         struct file *fpop;
  990         struct thread *td;
  991 
  992         td = curthread;
  993         fpop = td->td_fpop;
  994         error = devfs_fp_check(fp, &dev, &dsw, &ref);
  995         if (error)
  996                 return (error);
  997         error = dsw->d_kqfilter(dev, kn);
  998         td->td_fpop = fpop;
  999         dev_relthread(dev, ref);
 1000         return (error);
 1001 }
 1002 
 1003 static inline int
 1004 devfs_prison_check(struct devfs_dirent *de, struct thread *td)
 1005 {
 1006         struct cdev_priv *cdp;
 1007         struct ucred *dcr;
 1008         struct proc *p;
 1009         int error;
 1010 
 1011         cdp = de->de_cdp;
 1012         if (cdp == NULL)
 1013                 return (0);
 1014         dcr = cdp->cdp_c.si_cred;
 1015         if (dcr == NULL)
 1016                 return (0);
 1017 
 1018         error = prison_check(td->td_ucred, dcr);
 1019         if (error == 0)
 1020                 return (0);
 1021         /* We do, however, allow access to the controlling terminal */
 1022         p = td->td_proc;
 1023         PROC_LOCK(p);
 1024         if (!(p->p_flag & P_CONTROLT)) {
 1025                 PROC_UNLOCK(p);
 1026                 return (error);
 1027         }
 1028         if (p->p_session->s_ttydp == cdp)
 1029                 error = 0;
 1030         PROC_UNLOCK(p);
 1031         return (error);
 1032 }
 1033 
 1034 static int
 1035 devfs_lookupx(struct vop_lookup_args *ap, int *dm_unlock)
 1036 {
 1037         struct componentname *cnp;
 1038         struct vnode *dvp, **vpp;
 1039         struct thread *td;
 1040         struct devfs_dirent *de, *dd;
 1041         struct devfs_dirent **dde;
 1042         struct devfs_mount *dmp;
 1043         struct mount *mp;
 1044         struct cdev *cdev;
 1045         int error, flags, nameiop, dvplocked;
 1046         char specname[SPECNAMELEN + 1], *pname;
 1047 
 1048         cnp = ap->a_cnp;
 1049         vpp = ap->a_vpp;
 1050         dvp = ap->a_dvp;
 1051         pname = cnp->cn_nameptr;
 1052         td = cnp->cn_thread;
 1053         flags = cnp->cn_flags;
 1054         nameiop = cnp->cn_nameiop;
 1055         mp = dvp->v_mount;
 1056         dmp = VFSTODEVFS(mp);
 1057         dd = dvp->v_data;
 1058         *vpp = NULLVP;
 1059 
 1060         if ((flags & ISLASTCN) && nameiop == RENAME)
 1061                 return (EOPNOTSUPP);
 1062 
 1063         if (dvp->v_type != VDIR)
 1064                 return (ENOTDIR);
 1065 
 1066         if ((flags & ISDOTDOT) && (dvp->v_vflag & VV_ROOT))
 1067                 return (EIO);
 1068 
 1069         error = vn_dir_check_exec(dvp, cnp);
 1070         if (error != 0)
 1071                 return (error);
 1072 
 1073         if (cnp->cn_namelen == 1 && *pname == '.') {
 1074                 if ((flags & ISLASTCN) && nameiop != LOOKUP)
 1075                         return (EINVAL);
 1076                 *vpp = dvp;
 1077                 VREF(dvp);
 1078                 return (0);
 1079         }
 1080 
 1081         if (flags & ISDOTDOT) {
 1082                 if ((flags & ISLASTCN) && nameiop != LOOKUP)
 1083                         return (EINVAL);
 1084                 de = devfs_parent_dirent(dd);
 1085                 if (de == NULL)
 1086                         return (ENOENT);
 1087                 dvplocked = VOP_ISLOCKED(dvp);
 1088                 VOP_UNLOCK(dvp);
 1089                 error = devfs_allocv(de, mp, cnp->cn_lkflags & LK_TYPE_MASK,
 1090                     vpp);
 1091                 *dm_unlock = 0;
 1092                 vn_lock(dvp, dvplocked | LK_RETRY);
 1093                 return (error);
 1094         }
 1095 
 1096         dd = dvp->v_data;
 1097         de = devfs_find(dd, cnp->cn_nameptr, cnp->cn_namelen, 0);
 1098         while (de == NULL) {    /* While(...) so we can use break */
 1099 
 1100                 if (nameiop == DELETE)
 1101                         return (ENOENT);
 1102 
 1103                 /*
 1104                  * OK, we didn't have an entry for the name we were asked for
 1105                  * so we try to see if anybody can create it on demand.
 1106                  */
 1107                 pname = devfs_fqpn(specname, dmp, dd, cnp);
 1108                 if (pname == NULL)
 1109                         break;
 1110 
 1111                 cdev = NULL;
 1112                 DEVFS_DMP_HOLD(dmp);
 1113                 sx_xunlock(&dmp->dm_lock);
 1114                 sx_slock(&clone_drain_lock);
 1115                 EVENTHANDLER_INVOKE(dev_clone,
 1116                     td->td_ucred, pname, strlen(pname), &cdev);
 1117                 sx_sunlock(&clone_drain_lock);
 1118 
 1119                 if (cdev == NULL)
 1120                         sx_xlock(&dmp->dm_lock);
 1121                 else if (devfs_populate_vp(dvp) != 0) {
 1122                         *dm_unlock = 0;
 1123                         sx_xlock(&dmp->dm_lock);
 1124                         if (DEVFS_DMP_DROP(dmp)) {
 1125                                 sx_xunlock(&dmp->dm_lock);
 1126                                 devfs_unmount_final(dmp);
 1127                         } else
 1128                                 sx_xunlock(&dmp->dm_lock);
 1129                         dev_rel(cdev);
 1130                         return (ENOENT);
 1131                 }
 1132                 if (DEVFS_DMP_DROP(dmp)) {
 1133                         *dm_unlock = 0;
 1134                         sx_xunlock(&dmp->dm_lock);
 1135                         devfs_unmount_final(dmp);
 1136                         if (cdev != NULL)
 1137                                 dev_rel(cdev);
 1138                         return (ENOENT);
 1139                 }
 1140 
 1141                 if (cdev == NULL)
 1142                         break;
 1143 
 1144                 dev_lock();
 1145                 dde = &cdev2priv(cdev)->cdp_dirents[dmp->dm_idx];
 1146                 if (dde != NULL && *dde != NULL)
 1147                         de = *dde;
 1148                 dev_unlock();
 1149                 dev_rel(cdev);
 1150                 break;
 1151         }
 1152 
 1153         if (de == NULL || de->de_flags & DE_WHITEOUT) {
 1154                 if ((nameiop == CREATE || nameiop == RENAME) &&
 1155                     (flags & (LOCKPARENT | WANTPARENT)) && (flags & ISLASTCN)) {
 1156                         cnp->cn_flags |= SAVENAME;
 1157                         return (EJUSTRETURN);
 1158                 }
 1159                 return (ENOENT);
 1160         }
 1161 
 1162         if (devfs_prison_check(de, td))
 1163                 return (ENOENT);
 1164 
 1165         if ((cnp->cn_nameiop == DELETE) && (flags & ISLASTCN)) {
 1166                 error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, td);
 1167                 if (error)
 1168                         return (error);
 1169                 if (*vpp == dvp) {
 1170                         VREF(dvp);
 1171                         *vpp = dvp;
 1172                         return (0);
 1173                 }
 1174         }
 1175         error = devfs_allocv(de, mp, cnp->cn_lkflags & LK_TYPE_MASK, vpp);
 1176         *dm_unlock = 0;
 1177         return (error);
 1178 }
 1179 
 1180 static int
 1181 devfs_lookup(struct vop_lookup_args *ap)
 1182 {
 1183         int j;
 1184         struct devfs_mount *dmp;
 1185         int dm_unlock;
 1186 
 1187         if (devfs_populate_vp(ap->a_dvp) != 0)
 1188                 return (ENOTDIR);
 1189 
 1190         dmp = VFSTODEVFS(ap->a_dvp->v_mount);
 1191         dm_unlock = 1;
 1192         j = devfs_lookupx(ap, &dm_unlock);
 1193         if (dm_unlock == 1)
 1194                 sx_xunlock(&dmp->dm_lock);
 1195         return (j);
 1196 }
 1197 
 1198 static int
 1199 devfs_mknod(struct vop_mknod_args *ap)
 1200 {
 1201         struct componentname *cnp;
 1202         struct vnode *dvp, **vpp;
 1203         struct devfs_dirent *dd, *de;
 1204         struct devfs_mount *dmp;
 1205         int error;
 1206 
 1207         /*
 1208          * The only type of node we should be creating here is a
 1209          * character device, for anything else return EOPNOTSUPP.
 1210          */
 1211         if (ap->a_vap->va_type != VCHR)
 1212                 return (EOPNOTSUPP);
 1213         dvp = ap->a_dvp;
 1214         dmp = VFSTODEVFS(dvp->v_mount);
 1215 
 1216         cnp = ap->a_cnp;
 1217         vpp = ap->a_vpp;
 1218         dd = dvp->v_data;
 1219 
 1220         error = ENOENT;
 1221         sx_xlock(&dmp->dm_lock);
 1222         TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
 1223                 if (cnp->cn_namelen != de->de_dirent->d_namlen)
 1224                         continue;
 1225                 if (de->de_dirent->d_type == DT_CHR &&
 1226                     (de->de_cdp->cdp_flags & CDP_ACTIVE) == 0)
 1227                         continue;
 1228                 if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
 1229                     de->de_dirent->d_namlen) != 0)
 1230                         continue;
 1231                 if (de->de_flags & DE_WHITEOUT)
 1232                         break;
 1233                 goto notfound;
 1234         }
 1235         if (de == NULL)
 1236                 goto notfound;
 1237         de->de_flags &= ~DE_WHITEOUT;
 1238         error = devfs_allocv(de, dvp->v_mount, LK_EXCLUSIVE, vpp);
 1239         return (error);
 1240 notfound:
 1241         sx_xunlock(&dmp->dm_lock);
 1242         return (error);
 1243 }
 1244 
 1245 /* ARGSUSED */
 1246 static int
 1247 devfs_open(struct vop_open_args *ap)
 1248 {
 1249         struct thread *td = ap->a_td;
 1250         struct vnode *vp = ap->a_vp;
 1251         struct cdev *dev = vp->v_rdev;
 1252         struct file *fp = ap->a_fp;
 1253         int error, ref, vlocked;
 1254         struct cdevsw *dsw;
 1255         struct file *fpop;
 1256 
 1257         if (vp->v_type == VBLK)
 1258                 return (ENXIO);
 1259 
 1260         if (dev == NULL)
 1261                 return (ENXIO);
 1262 
 1263         /* Make this field valid before any I/O in d_open. */
 1264         if (dev->si_iosize_max == 0)
 1265                 dev->si_iosize_max = DFLTPHYS;
 1266 
 1267         dsw = dev_refthread(dev, &ref);
 1268         if (dsw == NULL)
 1269                 return (ENXIO);
 1270         if (fp == NULL && dsw->d_fdopen != NULL) {
 1271                 dev_relthread(dev, ref);
 1272                 return (ENXIO);
 1273         }
 1274 
 1275         if (vp->v_type == VCHR)
 1276                 devfs_usecount_add(vp);
 1277 
 1278         vlocked = VOP_ISLOCKED(vp);
 1279         VOP_UNLOCK(vp);
 1280 
 1281         fpop = td->td_fpop;
 1282         td->td_fpop = fp;
 1283         if (fp != NULL) {
 1284                 fp->f_data = dev;
 1285                 fp->f_vnode = vp;
 1286         }
 1287         if (dsw->d_fdopen != NULL)
 1288                 error = dsw->d_fdopen(dev, ap->a_mode, td, fp);
 1289         else
 1290                 error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
 1291         /* Clean up any cdevpriv upon error. */
 1292         if (error != 0)
 1293                 devfs_clear_cdevpriv();
 1294         td->td_fpop = fpop;
 1295 
 1296         vn_lock(vp, vlocked | LK_RETRY);
 1297         if (error != 0 && vp->v_type == VCHR)
 1298                 devfs_usecount_sub(vp);
 1299 
 1300         dev_relthread(dev, ref);
 1301         if (error != 0) {
 1302                 if (error == ERESTART)
 1303                         error = EINTR;
 1304                 return (error);
 1305         }
 1306 
 1307 #if 0   /* /dev/console */
 1308         KASSERT(fp != NULL, ("Could not vnode bypass device on NULL fp"));
 1309 #else
 1310         if (fp == NULL)
 1311                 return (error);
 1312 #endif
 1313         if (fp->f_ops == &badfileops)
 1314                 finit(fp, fp->f_flag, DTYPE_VNODE, dev, &devfs_ops_f);
 1315         return (error);
 1316 }
 1317 
 1318 static int
 1319 devfs_pathconf(struct vop_pathconf_args *ap)
 1320 {
 1321 
 1322         switch (ap->a_name) {
 1323         case _PC_FILESIZEBITS:
 1324                 *ap->a_retval = 64;
 1325                 return (0);
 1326         case _PC_NAME_MAX:
 1327                 *ap->a_retval = NAME_MAX;
 1328                 return (0);
 1329         case _PC_LINK_MAX:
 1330                 *ap->a_retval = INT_MAX;
 1331                 return (0);
 1332         case _PC_SYMLINK_MAX:
 1333                 *ap->a_retval = MAXPATHLEN;
 1334                 return (0);
 1335         case _PC_MAX_CANON:
 1336                 if (ap->a_vp->v_vflag & VV_ISTTY) {
 1337                         *ap->a_retval = MAX_CANON;
 1338                         return (0);
 1339                 }
 1340                 return (EINVAL);
 1341         case _PC_MAX_INPUT:
 1342                 if (ap->a_vp->v_vflag & VV_ISTTY) {
 1343                         *ap->a_retval = MAX_INPUT;
 1344                         return (0);
 1345                 }
 1346                 return (EINVAL);
 1347         case _PC_VDISABLE:
 1348                 if (ap->a_vp->v_vflag & VV_ISTTY) {
 1349                         *ap->a_retval = _POSIX_VDISABLE;
 1350                         return (0);
 1351                 }
 1352                 return (EINVAL);
 1353         case _PC_MAC_PRESENT:
 1354 #ifdef MAC
 1355                 /*
 1356                  * If MAC is enabled, devfs automatically supports
 1357                  * trivial non-persistent label storage.
 1358                  */
 1359                 *ap->a_retval = 1;
 1360 #else
 1361                 *ap->a_retval = 0;
 1362 #endif
 1363                 return (0);
 1364         case _PC_CHOWN_RESTRICTED:
 1365                 *ap->a_retval = 1;
 1366                 return (0);
 1367         default:
 1368                 return (vop_stdpathconf(ap));
 1369         }
 1370         /* NOTREACHED */
 1371 }
 1372 
 1373 /* ARGSUSED */
 1374 static int
 1375 devfs_poll_f(struct file *fp, int events, struct ucred *cred, struct thread *td)
 1376 {
 1377         struct cdev *dev;
 1378         struct cdevsw *dsw;
 1379         int error, ref;
 1380         struct file *fpop;
 1381 
 1382         fpop = td->td_fpop;
 1383         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1384         if (error != 0) {
 1385                 error = vnops.fo_poll(fp, events, cred, td);
 1386                 return (error);
 1387         }
 1388         error = dsw->d_poll(dev, events, td);
 1389         td->td_fpop = fpop;
 1390         dev_relthread(dev, ref);
 1391         return(error);
 1392 }
 1393 
 1394 /*
 1395  * Print out the contents of a special device vnode.
 1396  */
 1397 static int
 1398 devfs_print(struct vop_print_args *ap)
 1399 {
 1400 
 1401         printf("\tdev %s\n", devtoname(ap->a_vp->v_rdev));
 1402         return (0);
 1403 }
 1404 
 1405 static int
 1406 devfs_read_f(struct file *fp, struct uio *uio, struct ucred *cred,
 1407     int flags, struct thread *td)
 1408 {
 1409         struct cdev *dev;
 1410         int ioflag, error, ref;
 1411         ssize_t resid;
 1412         struct cdevsw *dsw;
 1413         struct file *fpop;
 1414 
 1415         if (uio->uio_resid > DEVFS_IOSIZE_MAX)
 1416                 return (EINVAL);
 1417         fpop = td->td_fpop;
 1418         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1419         if (error != 0) {
 1420                 error = vnops.fo_read(fp, uio, cred, flags, td);
 1421                 return (error);
 1422         }
 1423         resid = uio->uio_resid;
 1424         ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT);
 1425         if (ioflag & O_DIRECT)
 1426                 ioflag |= IO_DIRECT;
 1427 
 1428         foffset_lock_uio(fp, uio, flags | FOF_NOLOCK);
 1429         error = dsw->d_read(dev, uio, ioflag);
 1430         if (uio->uio_resid != resid || (error == 0 && resid != 0))
 1431                 devfs_timestamp(&dev->si_atime);
 1432         td->td_fpop = fpop;
 1433         dev_relthread(dev, ref);
 1434 
 1435         foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF_R);
 1436         return (error);
 1437 }
 1438 
 1439 static int
 1440 devfs_readdir(struct vop_readdir_args *ap)
 1441 {
 1442         int error;
 1443         struct uio *uio;
 1444         struct dirent *dp;
 1445         struct devfs_dirent *dd;
 1446         struct devfs_dirent *de;
 1447         struct devfs_mount *dmp;
 1448         off_t off;
 1449         int *tmp_ncookies = NULL;
 1450 
 1451         if (ap->a_vp->v_type != VDIR)
 1452                 return (ENOTDIR);
 1453 
 1454         uio = ap->a_uio;
 1455         if (uio->uio_offset < 0)
 1456                 return (EINVAL);
 1457 
 1458         /*
 1459          * XXX: This is a temporary hack to get around this filesystem not
 1460          * supporting cookies. We store the location of the ncookies pointer
 1461          * in a temporary variable before calling vfs_subr.c:vfs_read_dirent()
 1462          * and set the number of cookies to 0. We then set the pointer to
 1463          * NULL so that vfs_read_dirent doesn't try to call realloc() on 
 1464          * ap->a_cookies. Later in this function, we restore the ap->a_ncookies
 1465          * pointer to its original location before returning to the caller.
 1466          */
 1467         if (ap->a_ncookies != NULL) {
 1468                 tmp_ncookies = ap->a_ncookies;
 1469                 *ap->a_ncookies = 0;
 1470                 ap->a_ncookies = NULL;
 1471         }
 1472 
 1473         dmp = VFSTODEVFS(ap->a_vp->v_mount);
 1474         if (devfs_populate_vp(ap->a_vp) != 0) {
 1475                 if (tmp_ncookies != NULL)
 1476                         ap->a_ncookies = tmp_ncookies;
 1477                 return (EIO);
 1478         }
 1479         error = 0;
 1480         de = ap->a_vp->v_data;
 1481         off = 0;
 1482         TAILQ_FOREACH(dd, &de->de_dlist, de_list) {
 1483                 KASSERT(dd->de_cdp != (void *)0xdeadc0de, ("%s %d\n", __func__, __LINE__));
 1484                 if (dd->de_flags & (DE_COVERED | DE_WHITEOUT))
 1485                         continue;
 1486                 if (devfs_prison_check(dd, uio->uio_td))
 1487                         continue;
 1488                 if (dd->de_dirent->d_type == DT_DIR)
 1489                         de = dd->de_dir;
 1490                 else
 1491                         de = dd;
 1492                 dp = dd->de_dirent;
 1493                 MPASS(dp->d_reclen == GENERIC_DIRSIZ(dp));
 1494                 if (dp->d_reclen > uio->uio_resid)
 1495                         break;
 1496                 dp->d_fileno = de->de_inode;
 1497                 /* NOTE: d_off is the offset for the *next* entry. */
 1498                 dp->d_off = off + dp->d_reclen;
 1499                 if (off >= uio->uio_offset) {
 1500                         error = vfs_read_dirent(ap, dp, off);
 1501                         if (error)
 1502                                 break;
 1503                 }
 1504                 off += dp->d_reclen;
 1505         }
 1506         sx_xunlock(&dmp->dm_lock);
 1507         uio->uio_offset = off;
 1508 
 1509         /*
 1510          * Restore ap->a_ncookies if it wasn't originally NULL in the first
 1511          * place.
 1512          */
 1513         if (tmp_ncookies != NULL)
 1514                 ap->a_ncookies = tmp_ncookies;
 1515 
 1516         return (error);
 1517 }
 1518 
 1519 static int
 1520 devfs_readlink(struct vop_readlink_args *ap)
 1521 {
 1522         struct devfs_dirent *de;
 1523 
 1524         de = ap->a_vp->v_data;
 1525         return (uiomove(de->de_symlink, strlen(de->de_symlink), ap->a_uio));
 1526 }
 1527 
 1528 static void
 1529 devfs_reclaiml(struct vnode *vp)
 1530 {
 1531         struct devfs_dirent *de;
 1532 
 1533         mtx_assert(&devfs_de_interlock, MA_OWNED);
 1534         de = vp->v_data;
 1535         if (de != NULL) {
 1536                 MPASS(de->de_usecount == 0);
 1537                 de->de_vnode = NULL;
 1538                 vp->v_data = NULL;
 1539         }
 1540 }
 1541 
 1542 static int
 1543 devfs_reclaim(struct vop_reclaim_args *ap)
 1544 {
 1545         struct vnode *vp;
 1546 
 1547         vp = ap->a_vp;
 1548         mtx_lock(&devfs_de_interlock);
 1549         devfs_reclaiml(vp);
 1550         mtx_unlock(&devfs_de_interlock);
 1551         return (0);
 1552 }
 1553 
 1554 static int
 1555 devfs_reclaim_vchr(struct vop_reclaim_args *ap)
 1556 {
 1557         struct vnode *vp;
 1558         struct cdev *dev;
 1559 
 1560         vp = ap->a_vp;
 1561         MPASS(vp->v_type == VCHR);
 1562 
 1563         mtx_lock(&devfs_de_interlock);
 1564         VI_LOCK(vp);
 1565         devfs_usecount_subl(vp);
 1566         devfs_reclaiml(vp);
 1567         mtx_unlock(&devfs_de_interlock);
 1568         dev_lock();
 1569         dev = vp->v_rdev;
 1570         vp->v_rdev = NULL;
 1571         dev_unlock();
 1572         VI_UNLOCK(vp);
 1573         if (dev != NULL)
 1574                 dev_rel(dev);
 1575         return (0);
 1576 }
 1577 
 1578 static int
 1579 devfs_remove(struct vop_remove_args *ap)
 1580 {
 1581         struct vnode *dvp = ap->a_dvp;
 1582         struct vnode *vp = ap->a_vp;
 1583         struct devfs_dirent *dd;
 1584         struct devfs_dirent *de, *de_covered;
 1585         struct devfs_mount *dmp = VFSTODEVFS(vp->v_mount);
 1586 
 1587         ASSERT_VOP_ELOCKED(dvp, "devfs_remove");
 1588         ASSERT_VOP_ELOCKED(vp, "devfs_remove");
 1589 
 1590         sx_xlock(&dmp->dm_lock);
 1591         dd = ap->a_dvp->v_data;
 1592         de = vp->v_data;
 1593         if (de->de_cdp == NULL) {
 1594                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
 1595                 if (de->de_dirent->d_type == DT_LNK) {
 1596                         de_covered = devfs_find(dd, de->de_dirent->d_name,
 1597                             de->de_dirent->d_namlen, 0);
 1598                         if (de_covered != NULL)
 1599                                 de_covered->de_flags &= ~DE_COVERED;
 1600                 }
 1601                 /* We need to unlock dvp because devfs_delete() may lock it. */
 1602                 VOP_UNLOCK(vp);
 1603                 if (dvp != vp)
 1604                         VOP_UNLOCK(dvp);
 1605                 devfs_delete(dmp, de, 0);
 1606                 sx_xunlock(&dmp->dm_lock);
 1607                 if (dvp != vp)
 1608                         vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
 1609                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1610         } else {
 1611                 de->de_flags |= DE_WHITEOUT;
 1612                 sx_xunlock(&dmp->dm_lock);
 1613         }
 1614         return (0);
 1615 }
 1616 
 1617 /*
 1618  * Revoke is called on a tty when a terminal session ends.  The vnode
 1619  * is orphaned by setting v_op to deadfs so we need to let go of it
 1620  * as well so that we create a new one next time around.
 1621  *
 1622  */
 1623 static int
 1624 devfs_revoke(struct vop_revoke_args *ap)
 1625 {
 1626         struct vnode *vp = ap->a_vp, *vp2;
 1627         struct cdev *dev;
 1628         struct cdev_priv *cdp;
 1629         struct devfs_dirent *de;
 1630         enum vgetstate vs;
 1631         u_int i;
 1632 
 1633         KASSERT((ap->a_flags & REVOKEALL) != 0, ("devfs_revoke !REVOKEALL"));
 1634 
 1635         dev = vp->v_rdev;
 1636         cdp = cdev2priv(dev);
 1637 
 1638         dev_lock();
 1639         cdp->cdp_inuse++;
 1640         dev_unlock();
 1641 
 1642         vhold(vp);
 1643         vgone(vp);
 1644         vdrop(vp);
 1645 
 1646         VOP_UNLOCK(vp);
 1647  loop:
 1648         for (;;) {
 1649                 mtx_lock(&devfs_de_interlock);
 1650                 dev_lock();
 1651                 vp2 = NULL;
 1652                 for (i = 0; i <= cdp->cdp_maxdirent; i++) {
 1653                         de = cdp->cdp_dirents[i];
 1654                         if (de == NULL)
 1655                                 continue;
 1656 
 1657                         vp2 = de->de_vnode;
 1658                         if (vp2 != NULL) {
 1659                                 dev_unlock();
 1660                                 vs = vget_prep(vp2);
 1661                                 mtx_unlock(&devfs_de_interlock);
 1662                                 if (vget_finish(vp2, LK_EXCLUSIVE, vs) != 0)
 1663                                         goto loop;
 1664                                 vhold(vp2);
 1665                                 vgone(vp2);
 1666                                 vdrop(vp2);
 1667                                 vput(vp2);
 1668                                 break;
 1669                         }
 1670                 }
 1671                 if (vp2 != NULL) {
 1672                         continue;
 1673                 }
 1674                 dev_unlock();
 1675                 mtx_unlock(&devfs_de_interlock);
 1676                 break;
 1677         }
 1678         dev_lock();
 1679         cdp->cdp_inuse--;
 1680         if (!(cdp->cdp_flags & CDP_ACTIVE) && cdp->cdp_inuse == 0) {
 1681                 TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
 1682                 dev_unlock();
 1683                 dev_rel(&cdp->cdp_c);
 1684         } else
 1685                 dev_unlock();
 1686 
 1687         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1688         return (0);
 1689 }
 1690 
 1691 static int
 1692 devfs_rioctl(struct vop_ioctl_args *ap)
 1693 {
 1694         struct vnode *vp;
 1695         struct devfs_mount *dmp;
 1696         int error;
 1697 
 1698         vp = ap->a_vp;
 1699         vn_lock(vp, LK_SHARED | LK_RETRY);
 1700         if (VN_IS_DOOMED(vp)) {
 1701                 VOP_UNLOCK(vp);
 1702                 return (EBADF);
 1703         }
 1704         dmp = VFSTODEVFS(vp->v_mount);
 1705         sx_xlock(&dmp->dm_lock);
 1706         VOP_UNLOCK(vp);
 1707         DEVFS_DMP_HOLD(dmp);
 1708         devfs_populate(dmp);
 1709         if (DEVFS_DMP_DROP(dmp)) {
 1710                 sx_xunlock(&dmp->dm_lock);
 1711                 devfs_unmount_final(dmp);
 1712                 return (ENOENT);
 1713         }
 1714         error = devfs_rules_ioctl(dmp, ap->a_command, ap->a_data, ap->a_td);
 1715         sx_xunlock(&dmp->dm_lock);
 1716         return (error);
 1717 }
 1718 
 1719 static int
 1720 devfs_rread(struct vop_read_args *ap)
 1721 {
 1722 
 1723         if (ap->a_vp->v_type != VDIR)
 1724                 return (EINVAL);
 1725         return (VOP_READDIR(ap->a_vp, ap->a_uio, ap->a_cred, NULL, NULL, NULL));
 1726 }
 1727 
 1728 static int
 1729 devfs_setattr(struct vop_setattr_args *ap)
 1730 {
 1731         struct devfs_dirent *de;
 1732         struct vattr *vap;
 1733         struct vnode *vp;
 1734         struct thread *td;
 1735         int c, error;
 1736         uid_t uid;
 1737         gid_t gid;
 1738 
 1739         vap = ap->a_vap;
 1740         vp = ap->a_vp;
 1741         td = curthread;
 1742         if ((vap->va_type != VNON) ||
 1743             (vap->va_nlink != VNOVAL) ||
 1744             (vap->va_fsid != VNOVAL) ||
 1745             (vap->va_fileid != VNOVAL) ||
 1746             (vap->va_blocksize != VNOVAL) ||
 1747             (vap->va_flags != VNOVAL && vap->va_flags != 0) ||
 1748             (vap->va_rdev != VNOVAL) ||
 1749             ((int)vap->va_bytes != VNOVAL) ||
 1750             (vap->va_gen != VNOVAL)) {
 1751                 return (EINVAL);
 1752         }
 1753 
 1754         error = devfs_populate_vp(vp);
 1755         if (error != 0)
 1756                 return (error);
 1757 
 1758         de = vp->v_data;
 1759         if (vp->v_type == VDIR)
 1760                 de = de->de_dir;
 1761 
 1762         c = 0;
 1763         if (vap->va_uid == (uid_t)VNOVAL)
 1764                 uid = de->de_uid;
 1765         else
 1766                 uid = vap->va_uid;
 1767         if (vap->va_gid == (gid_t)VNOVAL)
 1768                 gid = de->de_gid;
 1769         else
 1770                 gid = vap->va_gid;
 1771         if (uid != de->de_uid || gid != de->de_gid) {
 1772                 if ((ap->a_cred->cr_uid != de->de_uid) || uid != de->de_uid ||
 1773                     (gid != de->de_gid && !groupmember(gid, ap->a_cred))) {
 1774                         error = priv_check(td, PRIV_VFS_CHOWN);
 1775                         if (error != 0)
 1776                                 goto ret;
 1777                 }
 1778                 de->de_uid = uid;
 1779                 de->de_gid = gid;
 1780                 c = 1;
 1781         }
 1782 
 1783         if (vap->va_mode != (mode_t)VNOVAL) {
 1784                 if (ap->a_cred->cr_uid != de->de_uid) {
 1785                         error = priv_check(td, PRIV_VFS_ADMIN);
 1786                         if (error != 0)
 1787                                 goto ret;
 1788                 }
 1789                 de->de_mode = vap->va_mode;
 1790                 c = 1;
 1791         }
 1792 
 1793         if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
 1794                 error = vn_utimes_perm(vp, vap, ap->a_cred, td);
 1795                 if (error != 0)
 1796                         goto ret;
 1797                 if (vap->va_atime.tv_sec != VNOVAL) {
 1798                         if (vp->v_type == VCHR)
 1799                                 vp->v_rdev->si_atime = vap->va_atime;
 1800                         else
 1801                                 de->de_atime = vap->va_atime;
 1802                 }
 1803                 if (vap->va_mtime.tv_sec != VNOVAL) {
 1804                         if (vp->v_type == VCHR)
 1805                                 vp->v_rdev->si_mtime = vap->va_mtime;
 1806                         else
 1807                                 de->de_mtime = vap->va_mtime;
 1808                 }
 1809                 c = 1;
 1810         }
 1811 
 1812         if (c) {
 1813                 if (vp->v_type == VCHR)
 1814                         vfs_timestamp(&vp->v_rdev->si_ctime);
 1815                 else
 1816                         vfs_timestamp(&de->de_mtime);
 1817         }
 1818 
 1819 ret:
 1820         sx_xunlock(&VFSTODEVFS(vp->v_mount)->dm_lock);
 1821         return (error);
 1822 }
 1823 
 1824 #ifdef MAC
 1825 static int
 1826 devfs_setlabel(struct vop_setlabel_args *ap)
 1827 {
 1828         struct vnode *vp;
 1829         struct devfs_dirent *de;
 1830 
 1831         vp = ap->a_vp;
 1832         de = vp->v_data;
 1833 
 1834         mac_vnode_relabel(ap->a_cred, vp, ap->a_label);
 1835         mac_devfs_update(vp->v_mount, de, vp);
 1836 
 1837         return (0);
 1838 }
 1839 #endif
 1840 
 1841 static int
 1842 devfs_stat_f(struct file *fp, struct stat *sb, struct ucred *cred, struct thread *td)
 1843 {
 1844 
 1845         return (vnops.fo_stat(fp, sb, cred, td));
 1846 }
 1847 
 1848 static int
 1849 devfs_symlink(struct vop_symlink_args *ap)
 1850 {
 1851         int i, error;
 1852         struct devfs_dirent *dd;
 1853         struct devfs_dirent *de, *de_covered, *de_dotdot;
 1854         struct devfs_mount *dmp;
 1855 
 1856         error = priv_check(curthread, PRIV_DEVFS_SYMLINK);
 1857         if (error)
 1858                 return(error);
 1859         dmp = VFSTODEVFS(ap->a_dvp->v_mount);
 1860         if (devfs_populate_vp(ap->a_dvp) != 0)
 1861                 return (ENOENT);
 1862 
 1863         dd = ap->a_dvp->v_data;
 1864         de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen);
 1865         de->de_flags = DE_USER;
 1866         de->de_uid = 0;
 1867         de->de_gid = 0;
 1868         de->de_mode = 0755;
 1869         de->de_inode = alloc_unr(devfs_inos);
 1870         de->de_dir = dd;
 1871         de->de_dirent->d_type = DT_LNK;
 1872         i = strlen(ap->a_target) + 1;
 1873         de->de_symlink = malloc(i, M_DEVFS, M_WAITOK);
 1874         bcopy(ap->a_target, de->de_symlink, i);
 1875 #ifdef MAC
 1876         mac_devfs_create_symlink(ap->a_cnp->cn_cred, dmp->dm_mount, dd, de);
 1877 #endif
 1878         de_covered = devfs_find(dd, de->de_dirent->d_name,
 1879             de->de_dirent->d_namlen, 0);
 1880         if (de_covered != NULL) {
 1881                 if ((de_covered->de_flags & DE_USER) != 0) {
 1882                         devfs_delete(dmp, de, DEVFS_DEL_NORECURSE);
 1883                         sx_xunlock(&dmp->dm_lock);
 1884                         return (EEXIST);
 1885                 }
 1886                 KASSERT((de_covered->de_flags & DE_COVERED) == 0,
 1887                     ("devfs_symlink: entry %p already covered", de_covered));
 1888                 de_covered->de_flags |= DE_COVERED;
 1889         }
 1890 
 1891         de_dotdot = TAILQ_FIRST(&dd->de_dlist);         /* "." */
 1892         de_dotdot = TAILQ_NEXT(de_dotdot, de_list);     /* ".." */
 1893         TAILQ_INSERT_AFTER(&dd->de_dlist, de_dotdot, de, de_list);
 1894         devfs_dir_ref_de(dmp, dd);
 1895         devfs_rules_apply(dmp, de);
 1896 
 1897         return (devfs_allocv(de, ap->a_dvp->v_mount, LK_EXCLUSIVE, ap->a_vpp));
 1898 }
 1899 
 1900 static int
 1901 devfs_truncate_f(struct file *fp, off_t length, struct ucred *cred, struct thread *td)
 1902 {
 1903 
 1904         return (vnops.fo_truncate(fp, length, cred, td));
 1905 }
 1906 
 1907 static int
 1908 devfs_write_f(struct file *fp, struct uio *uio, struct ucred *cred,
 1909     int flags, struct thread *td)
 1910 {
 1911         struct cdev *dev;
 1912         int error, ioflag, ref;
 1913         ssize_t resid;
 1914         struct cdevsw *dsw;
 1915         struct file *fpop;
 1916 
 1917         if (uio->uio_resid > DEVFS_IOSIZE_MAX)
 1918                 return (EINVAL);
 1919         fpop = td->td_fpop;
 1920         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1921         if (error != 0) {
 1922                 error = vnops.fo_write(fp, uio, cred, flags, td);
 1923                 return (error);
 1924         }
 1925         KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", uio->uio_td, td));
 1926         ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT | O_FSYNC);
 1927         if (ioflag & O_DIRECT)
 1928                 ioflag |= IO_DIRECT;
 1929         foffset_lock_uio(fp, uio, flags | FOF_NOLOCK);
 1930 
 1931         resid = uio->uio_resid;
 1932 
 1933         error = dsw->d_write(dev, uio, ioflag);
 1934         if (uio->uio_resid != resid || (error == 0 && resid != 0)) {
 1935                 devfs_timestamp(&dev->si_ctime);
 1936                 dev->si_mtime = dev->si_ctime;
 1937         }
 1938         td->td_fpop = fpop;
 1939         dev_relthread(dev, ref);
 1940 
 1941         foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF_W);
 1942         return (error);
 1943 }
 1944 
 1945 static int
 1946 devfs_mmap_f(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size,
 1947     vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff,
 1948     struct thread *td)
 1949 {
 1950         struct cdev *dev;
 1951         struct cdevsw *dsw;
 1952         struct mount *mp;
 1953         struct vnode *vp;
 1954         struct file *fpop;
 1955         vm_object_t object;
 1956         vm_prot_t maxprot;
 1957         int error, ref;
 1958 
 1959         vp = fp->f_vnode;
 1960 
 1961         /*
 1962          * Ensure that file and memory protections are
 1963          * compatible.
 1964          */
 1965         mp = vp->v_mount;
 1966         if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) {
 1967                 maxprot = VM_PROT_NONE;
 1968                 if ((prot & VM_PROT_EXECUTE) != 0)
 1969                         return (EACCES);
 1970         } else
 1971                 maxprot = VM_PROT_EXECUTE;
 1972         if ((fp->f_flag & FREAD) != 0)
 1973                 maxprot |= VM_PROT_READ;
 1974         else if ((prot & VM_PROT_READ) != 0)
 1975                 return (EACCES);
 1976 
 1977         /*
 1978          * If we are sharing potential changes via MAP_SHARED and we
 1979          * are trying to get write permission although we opened it
 1980          * without asking for it, bail out.
 1981          *
 1982          * Note that most character devices always share mappings.
 1983          * The one exception is that D_MMAP_ANON devices
 1984          * (i.e. /dev/zero) permit private writable mappings.
 1985          *
 1986          * Rely on vm_mmap_cdev() to fail invalid MAP_PRIVATE requests
 1987          * as well as updating maxprot to permit writing for
 1988          * D_MMAP_ANON devices rather than doing that here.
 1989          */
 1990         if ((flags & MAP_SHARED) != 0) {
 1991                 if ((fp->f_flag & FWRITE) != 0)
 1992                         maxprot |= VM_PROT_WRITE;
 1993                 else if ((prot & VM_PROT_WRITE) != 0)
 1994                         return (EACCES);
 1995         }
 1996         maxprot &= cap_maxprot;
 1997 
 1998         fpop = td->td_fpop;
 1999         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 2000         if (error != 0)
 2001                 return (error);
 2002 
 2003         error = vm_mmap_cdev(td, size, prot, &maxprot, &flags, dev, dsw, &foff,
 2004             &object);
 2005         td->td_fpop = fpop;
 2006         dev_relthread(dev, ref);
 2007         if (error != 0)
 2008                 return (error);
 2009 
 2010         error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object,
 2011             foff, FALSE, td);
 2012         if (error != 0)
 2013                 vm_object_deallocate(object);
 2014         return (error);
 2015 }
 2016 
 2017 dev_t
 2018 dev2udev(struct cdev *x)
 2019 {
 2020         if (x == NULL)
 2021                 return (NODEV);
 2022         return (cdev2priv(x)->cdp_inode);
 2023 }
 2024 
 2025 static struct fileops devfs_ops_f = {
 2026         .fo_read =      devfs_read_f,
 2027         .fo_write =     devfs_write_f,
 2028         .fo_truncate =  devfs_truncate_f,
 2029         .fo_ioctl =     devfs_ioctl_f,
 2030         .fo_poll =      devfs_poll_f,
 2031         .fo_kqfilter =  devfs_kqfilter_f,
 2032         .fo_stat =      devfs_stat_f,
 2033         .fo_close =     devfs_close_f,
 2034         .fo_chmod =     vn_chmod,
 2035         .fo_chown =     vn_chown,
 2036         .fo_sendfile =  vn_sendfile,
 2037         .fo_seek =      vn_seek,
 2038         .fo_fill_kinfo = vn_fill_kinfo,
 2039         .fo_mmap =      devfs_mmap_f,
 2040         .fo_flags =     DFLAG_PASSABLE | DFLAG_SEEKABLE
 2041 };
 2042 
 2043 /* Vops for non-CHR vnodes in /dev. */
 2044 static struct vop_vector devfs_vnodeops = {
 2045         .vop_default =          &default_vnodeops,
 2046 
 2047         .vop_access =           devfs_access,
 2048         .vop_getattr =          devfs_getattr,
 2049         .vop_ioctl =            devfs_rioctl,
 2050         .vop_lookup =           devfs_lookup,
 2051         .vop_mknod =            devfs_mknod,
 2052         .vop_pathconf =         devfs_pathconf,
 2053         .vop_read =             devfs_rread,
 2054         .vop_readdir =          devfs_readdir,
 2055         .vop_readlink =         devfs_readlink,
 2056         .vop_reclaim =          devfs_reclaim,
 2057         .vop_remove =           devfs_remove,
 2058         .vop_revoke =           devfs_revoke,
 2059         .vop_setattr =          devfs_setattr,
 2060 #ifdef MAC
 2061         .vop_setlabel =         devfs_setlabel,
 2062 #endif
 2063         .vop_symlink =          devfs_symlink,
 2064         .vop_vptocnp =          devfs_vptocnp,
 2065         .vop_lock1 =            vop_lock,
 2066         .vop_unlock =           vop_unlock,
 2067         .vop_islocked =         vop_islocked,
 2068 };
 2069 VFS_VOP_VECTOR_REGISTER(devfs_vnodeops);
 2070 
 2071 /* Vops for VCHR vnodes in /dev. */
 2072 static struct vop_vector devfs_specops = {
 2073         .vop_default =          &default_vnodeops,
 2074 
 2075         .vop_access =           devfs_access,
 2076         .vop_bmap =             VOP_PANIC,
 2077         .vop_close =            devfs_close,
 2078         .vop_create =           VOP_PANIC,
 2079         .vop_fsync =            vop_stdfsync,
 2080         .vop_getattr =          devfs_getattr,
 2081         .vop_ioctl =            devfs_ioctl,
 2082         .vop_link =             VOP_PANIC,
 2083         .vop_mkdir =            VOP_PANIC,
 2084         .vop_mknod =            VOP_PANIC,
 2085         .vop_open =             devfs_open,
 2086         .vop_pathconf =         devfs_pathconf,
 2087         .vop_poll =             dead_poll,
 2088         .vop_print =            devfs_print,
 2089         .vop_read =             dead_read,
 2090         .vop_readdir =          VOP_PANIC,
 2091         .vop_readlink =         VOP_PANIC,
 2092         .vop_reallocblks =      VOP_PANIC,
 2093         .vop_reclaim =          devfs_reclaim_vchr,
 2094         .vop_remove =           devfs_remove,
 2095         .vop_rename =           VOP_PANIC,
 2096         .vop_revoke =           devfs_revoke,
 2097         .vop_rmdir =            VOP_PANIC,
 2098         .vop_setattr =          devfs_setattr,
 2099 #ifdef MAC
 2100         .vop_setlabel =         devfs_setlabel,
 2101 #endif
 2102         .vop_strategy =         VOP_PANIC,
 2103         .vop_symlink =          VOP_PANIC,
 2104         .vop_vptocnp =          devfs_vptocnp,
 2105         .vop_write =            dead_write,
 2106         .vop_lock1 =            vop_lock,
 2107         .vop_unlock =           vop_unlock,
 2108         .vop_islocked =         vop_islocked,
 2109 };
 2110 VFS_VOP_VECTOR_REGISTER(devfs_specops);
 2111 
 2112 /*
 2113  * Our calling convention to the device drivers used to be that we passed
 2114  * vnode.h IO_* flags to read()/write(), but we're moving to fcntl.h O_ 
 2115  * flags instead since that's what open(), close() and ioctl() takes and
 2116  * we don't really want vnode.h in device drivers.
 2117  * We solved the source compatibility by redefining some vnode flags to
 2118  * be the same as the fcntl ones and by sending down the bitwise OR of
 2119  * the respective fcntl/vnode flags.  These CTASSERTS make sure nobody
 2120  * pulls the rug out under this.
 2121  */
 2122 CTASSERT(O_NONBLOCK == IO_NDELAY);
 2123 CTASSERT(O_FSYNC == IO_SYNC);
Cache object: e6da731dc9f92bc46c8b470d77956f89
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FreeBSD/Linux Kernel Cross Reference sys/fs/devfs/devfs_vnops.c

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