The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/fs/devfs/devfs_vnops.c

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    1 /*-
    2  * Copyright (c) 2000-2004
    3  *      Poul-Henning Kamp.  All rights reserved.
    4  * Copyright (c) 1989, 1992-1993, 1995
    5  *      The Regents of the University of California.  All rights reserved.
    6  *
    7  * This code is derived from software donated to Berkeley by
    8  * Jan-Simon Pendry.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Neither the name of the University nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  *
   31  *      @(#)kernfs_vnops.c      8.15 (Berkeley) 5/21/95
   32  * From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vnops.c 1.43
   33  *
   34  * $FreeBSD: releng/10.4/sys/fs/devfs/devfs_vnops.c 302078 2016-06-22 09:08:18Z kib $
   35  */
   36 
   37 /*
   38  * TODO:
   39  *      mkdir: want it ?
   40  */
   41 
   42 #include <sys/param.h>
   43 #include <sys/systm.h>
   44 #include <sys/conf.h>
   45 #include <sys/dirent.h>
   46 #include <sys/fcntl.h>
   47 #include <sys/file.h>
   48 #include <sys/filedesc.h>
   49 #include <sys/filio.h>
   50 #include <sys/jail.h>
   51 #include <sys/kernel.h>
   52 #include <sys/lock.h>
   53 #include <sys/malloc.h>
   54 #include <sys/mount.h>
   55 #include <sys/namei.h>
   56 #include <sys/priv.h>
   57 #include <sys/proc.h>
   58 #include <sys/stat.h>
   59 #include <sys/sx.h>
   60 #include <sys/sysctl.h>
   61 #include <sys/time.h>
   62 #include <sys/ttycom.h>
   63 #include <sys/unistd.h>
   64 #include <sys/vnode.h>
   65 
   66 static struct vop_vector devfs_vnodeops;
   67 static struct vop_vector devfs_specops;
   68 static struct fileops devfs_ops_f;
   69 
   70 #include <fs/devfs/devfs.h>
   71 #include <fs/devfs/devfs_int.h>
   72 
   73 #include <security/mac/mac_framework.h>
   74 
   75 static MALLOC_DEFINE(M_CDEVPDATA, "DEVFSP", "Metainfo for cdev-fp data");
   76 
   77 struct mtx      devfs_de_interlock;
   78 MTX_SYSINIT(devfs_de_interlock, &devfs_de_interlock, "devfs interlock", MTX_DEF);
   79 struct sx       clone_drain_lock;
   80 SX_SYSINIT(clone_drain_lock, &clone_drain_lock, "clone events drain lock");
   81 struct mtx      cdevpriv_mtx;
   82 MTX_SYSINIT(cdevpriv_mtx, &cdevpriv_mtx, "cdevpriv lock", MTX_DEF);
   83 
   84 SYSCTL_DECL(_vfs_devfs);
   85 
   86 static int devfs_dotimes;
   87 SYSCTL_INT(_vfs_devfs, OID_AUTO, dotimes, CTLFLAG_RW,
   88     &devfs_dotimes, 0, "Update timestamps on DEVFS with default precision");
   89 
   90 /*
   91  * Update devfs node timestamp.  Note that updates are unlocked and
   92  * stat(2) could see partially updated times.
   93  */
   94 static void
   95 devfs_timestamp(struct timespec *tsp)
   96 {
   97         time_t ts;
   98 
   99         if (devfs_dotimes) {
  100                 vfs_timestamp(tsp);
  101         } else {
  102                 ts = time_second;
  103                 if (tsp->tv_sec != ts) {
  104                         tsp->tv_sec = ts;
  105                         tsp->tv_nsec = 0;
  106                 }
  107         }
  108 }
  109 
  110 static int
  111 devfs_fp_check(struct file *fp, struct cdev **devp, struct cdevsw **dswp,
  112     int *ref)
  113 {
  114 
  115         *dswp = devvn_refthread(fp->f_vnode, devp, ref);
  116         if (*devp != fp->f_data) {
  117                 if (*dswp != NULL)
  118                         dev_relthread(*devp, *ref);
  119                 return (ENXIO);
  120         }
  121         KASSERT((*devp)->si_refcount > 0,
  122             ("devfs: un-referenced struct cdev *(%s)", devtoname(*devp)));
  123         if (*dswp == NULL)
  124                 return (ENXIO);
  125         curthread->td_fpop = fp;
  126         return (0);
  127 }
  128 
  129 int
  130 devfs_get_cdevpriv(void **datap)
  131 {
  132         struct file *fp;
  133         struct cdev_privdata *p;
  134         int error;
  135 
  136         fp = curthread->td_fpop;
  137         if (fp == NULL)
  138                 return (EBADF);
  139         p = fp->f_cdevpriv;
  140         if (p != NULL) {
  141                 error = 0;
  142                 *datap = p->cdpd_data;
  143         } else
  144                 error = ENOENT;
  145         return (error);
  146 }
  147 
  148 int
  149 devfs_set_cdevpriv(void *priv, d_priv_dtor_t *priv_dtr)
  150 {
  151         struct file *fp;
  152         struct cdev_priv *cdp;
  153         struct cdev_privdata *p;
  154         int error;
  155 
  156         fp = curthread->td_fpop;
  157         if (fp == NULL)
  158                 return (ENOENT);
  159         cdp = cdev2priv((struct cdev *)fp->f_data);
  160         p = malloc(sizeof(struct cdev_privdata), M_CDEVPDATA, M_WAITOK);
  161         p->cdpd_data = priv;
  162         p->cdpd_dtr = priv_dtr;
  163         p->cdpd_fp = fp;
  164         mtx_lock(&cdevpriv_mtx);
  165         if (fp->f_cdevpriv == NULL) {
  166                 LIST_INSERT_HEAD(&cdp->cdp_fdpriv, p, cdpd_list);
  167                 fp->f_cdevpriv = p;
  168                 mtx_unlock(&cdevpriv_mtx);
  169                 error = 0;
  170         } else {
  171                 mtx_unlock(&cdevpriv_mtx);
  172                 free(p, M_CDEVPDATA);
  173                 error = EBUSY;
  174         }
  175         return (error);
  176 }
  177 
  178 void
  179 devfs_destroy_cdevpriv(struct cdev_privdata *p)
  180 {
  181 
  182         mtx_assert(&cdevpriv_mtx, MA_OWNED);
  183         p->cdpd_fp->f_cdevpriv = NULL;
  184         LIST_REMOVE(p, cdpd_list);
  185         mtx_unlock(&cdevpriv_mtx);
  186         (p->cdpd_dtr)(p->cdpd_data);
  187         free(p, M_CDEVPDATA);
  188 }
  189 
  190 void
  191 devfs_fpdrop(struct file *fp)
  192 {
  193         struct cdev_privdata *p;
  194 
  195         mtx_lock(&cdevpriv_mtx);
  196         if ((p = fp->f_cdevpriv) == NULL) {
  197                 mtx_unlock(&cdevpriv_mtx);
  198                 return;
  199         }
  200         devfs_destroy_cdevpriv(p);
  201 }
  202 
  203 void
  204 devfs_clear_cdevpriv(void)
  205 {
  206         struct file *fp;
  207 
  208         fp = curthread->td_fpop;
  209         if (fp == NULL)
  210                 return;
  211         devfs_fpdrop(fp);
  212 }
  213 
  214 /*
  215  * On success devfs_populate_vp() returns with dmp->dm_lock held.
  216  */
  217 static int
  218 devfs_populate_vp(struct vnode *vp)
  219 {
  220         struct devfs_dirent *de;
  221         struct devfs_mount *dmp;
  222         int locked;
  223 
  224         ASSERT_VOP_LOCKED(vp, "devfs_populate_vp");
  225 
  226         dmp = VFSTODEVFS(vp->v_mount);
  227         locked = VOP_ISLOCKED(vp);
  228 
  229         sx_xlock(&dmp->dm_lock);
  230         DEVFS_DMP_HOLD(dmp);
  231 
  232         /* Can't call devfs_populate() with the vnode lock held. */
  233         VOP_UNLOCK(vp, 0);
  234         devfs_populate(dmp);
  235 
  236         sx_xunlock(&dmp->dm_lock);
  237         vn_lock(vp, locked | LK_RETRY);
  238         sx_xlock(&dmp->dm_lock);
  239         if (DEVFS_DMP_DROP(dmp)) {
  240                 sx_xunlock(&dmp->dm_lock);
  241                 devfs_unmount_final(dmp);
  242                 return (ERESTART);
  243         }
  244         if ((vp->v_iflag & VI_DOOMED) != 0) {
  245                 sx_xunlock(&dmp->dm_lock);
  246                 return (ERESTART);
  247         }
  248         de = vp->v_data;
  249         KASSERT(de != NULL,
  250             ("devfs_populate_vp: vp->v_data == NULL but vnode not doomed"));
  251         if ((de->de_flags & DE_DOOMED) != 0) {
  252                 sx_xunlock(&dmp->dm_lock);
  253                 return (ERESTART);
  254         }
  255 
  256         return (0);
  257 }
  258 
  259 static int
  260 devfs_vptocnp(struct vop_vptocnp_args *ap)
  261 {
  262         struct vnode *vp = ap->a_vp;
  263         struct vnode **dvp = ap->a_vpp;
  264         struct devfs_mount *dmp;
  265         char *buf = ap->a_buf;
  266         int *buflen = ap->a_buflen;
  267         struct devfs_dirent *dd, *de;
  268         int i, error;
  269 
  270         dmp = VFSTODEVFS(vp->v_mount);
  271 
  272         error = devfs_populate_vp(vp);
  273         if (error != 0)
  274                 return (error);
  275 
  276         i = *buflen;
  277         dd = vp->v_data;
  278 
  279         if (vp->v_type == VCHR) {
  280                 i -= strlen(dd->de_cdp->cdp_c.si_name);
  281                 if (i < 0) {
  282                         error = ENOMEM;
  283                         goto finished;
  284                 }
  285                 bcopy(dd->de_cdp->cdp_c.si_name, buf + i,
  286                     strlen(dd->de_cdp->cdp_c.si_name));
  287                 de = dd->de_dir;
  288         } else if (vp->v_type == VDIR) {
  289                 if (dd == dmp->dm_rootdir) {
  290                         *dvp = vp;
  291                         vref(*dvp);
  292                         goto finished;
  293                 }
  294                 i -= dd->de_dirent->d_namlen;
  295                 if (i < 0) {
  296                         error = ENOMEM;
  297                         goto finished;
  298                 }
  299                 bcopy(dd->de_dirent->d_name, buf + i,
  300                     dd->de_dirent->d_namlen);
  301                 de = dd;
  302         } else {
  303                 error = ENOENT;
  304                 goto finished;
  305         }
  306         *buflen = i;
  307         de = devfs_parent_dirent(de);
  308         if (de == NULL) {
  309                 error = ENOENT;
  310                 goto finished;
  311         }
  312         mtx_lock(&devfs_de_interlock);
  313         *dvp = de->de_vnode;
  314         if (*dvp != NULL) {
  315                 VI_LOCK(*dvp);
  316                 mtx_unlock(&devfs_de_interlock);
  317                 vholdl(*dvp);
  318                 VI_UNLOCK(*dvp);
  319                 vref(*dvp);
  320                 vdrop(*dvp);
  321         } else {
  322                 mtx_unlock(&devfs_de_interlock);
  323                 error = ENOENT;
  324         }
  325 finished:
  326         sx_xunlock(&dmp->dm_lock);
  327         return (error);
  328 }
  329 
  330 /*
  331  * Construct the fully qualified path name relative to the mountpoint.
  332  * If a NULL cnp is provided, no '/' is appended to the resulting path.
  333  */
  334 char *
  335 devfs_fqpn(char *buf, struct devfs_mount *dmp, struct devfs_dirent *dd,
  336     struct componentname *cnp)
  337 {
  338         int i;
  339         struct devfs_dirent *de;
  340 
  341         sx_assert(&dmp->dm_lock, SA_LOCKED);
  342 
  343         i = SPECNAMELEN;
  344         buf[i] = '\0';
  345         if (cnp != NULL)
  346                 i -= cnp->cn_namelen;
  347         if (i < 0)
  348                  return (NULL);
  349         if (cnp != NULL)
  350                 bcopy(cnp->cn_nameptr, buf + i, cnp->cn_namelen);
  351         de = dd;
  352         while (de != dmp->dm_rootdir) {
  353                 if (cnp != NULL || i < SPECNAMELEN) {
  354                         i--;
  355                         if (i < 0)
  356                                  return (NULL);
  357                         buf[i] = '/';
  358                 }
  359                 i -= de->de_dirent->d_namlen;
  360                 if (i < 0)
  361                          return (NULL);
  362                 bcopy(de->de_dirent->d_name, buf + i,
  363                     de->de_dirent->d_namlen);
  364                 de = devfs_parent_dirent(de);
  365                 if (de == NULL)
  366                         return (NULL);
  367         }
  368         return (buf + i);
  369 }
  370 
  371 static int
  372 devfs_allocv_drop_refs(int drop_dm_lock, struct devfs_mount *dmp,
  373         struct devfs_dirent *de)
  374 {
  375         int not_found;
  376 
  377         not_found = 0;
  378         if (de->de_flags & DE_DOOMED)
  379                 not_found = 1;
  380         if (DEVFS_DE_DROP(de)) {
  381                 KASSERT(not_found == 1, ("DEVFS de dropped but not doomed"));
  382                 devfs_dirent_free(de);
  383         }
  384         if (DEVFS_DMP_DROP(dmp)) {
  385                 KASSERT(not_found == 1,
  386                         ("DEVFS mount struct freed before dirent"));
  387                 not_found = 2;
  388                 sx_xunlock(&dmp->dm_lock);
  389                 devfs_unmount_final(dmp);
  390         }
  391         if (not_found == 1 || (drop_dm_lock && not_found != 2))
  392                 sx_unlock(&dmp->dm_lock);
  393         return (not_found);
  394 }
  395 
  396 static void
  397 devfs_insmntque_dtr(struct vnode *vp, void *arg)
  398 {
  399         struct devfs_dirent *de;
  400 
  401         de = (struct devfs_dirent *)arg;
  402         mtx_lock(&devfs_de_interlock);
  403         vp->v_data = NULL;
  404         de->de_vnode = NULL;
  405         mtx_unlock(&devfs_de_interlock);
  406         vgone(vp);
  407         vput(vp);
  408 }
  409 
  410 /*
  411  * devfs_allocv shall be entered with dmp->dm_lock held, and it drops
  412  * it on return.
  413  */
  414 int
  415 devfs_allocv(struct devfs_dirent *de, struct mount *mp, int lockmode,
  416     struct vnode **vpp)
  417 {
  418         int error;
  419         struct vnode *vp;
  420         struct cdev *dev;
  421         struct devfs_mount *dmp;
  422         struct cdevsw *dsw;
  423 
  424         dmp = VFSTODEVFS(mp);
  425         if (de->de_flags & DE_DOOMED) {
  426                 sx_xunlock(&dmp->dm_lock);
  427                 return (ENOENT);
  428         }
  429 loop:
  430         DEVFS_DE_HOLD(de);
  431         DEVFS_DMP_HOLD(dmp);
  432         mtx_lock(&devfs_de_interlock);
  433         vp = de->de_vnode;
  434         if (vp != NULL) {
  435                 VI_LOCK(vp);
  436                 mtx_unlock(&devfs_de_interlock);
  437                 sx_xunlock(&dmp->dm_lock);
  438                 vget(vp, lockmode | LK_INTERLOCK | LK_RETRY, curthread);
  439                 sx_xlock(&dmp->dm_lock);
  440                 if (devfs_allocv_drop_refs(0, dmp, de)) {
  441                         vput(vp);
  442                         return (ENOENT);
  443                 }
  444                 else if ((vp->v_iflag & VI_DOOMED) != 0) {
  445                         mtx_lock(&devfs_de_interlock);
  446                         if (de->de_vnode == vp) {
  447                                 de->de_vnode = NULL;
  448                                 vp->v_data = NULL;
  449                         }
  450                         mtx_unlock(&devfs_de_interlock);
  451                         vput(vp);
  452                         goto loop;
  453                 }
  454                 sx_xunlock(&dmp->dm_lock);
  455                 *vpp = vp;
  456                 return (0);
  457         }
  458         mtx_unlock(&devfs_de_interlock);
  459         if (de->de_dirent->d_type == DT_CHR) {
  460                 if (!(de->de_cdp->cdp_flags & CDP_ACTIVE)) {
  461                         devfs_allocv_drop_refs(1, dmp, de);
  462                         return (ENOENT);
  463                 }
  464                 dev = &de->de_cdp->cdp_c;
  465         } else {
  466                 dev = NULL;
  467         }
  468         error = getnewvnode("devfs", mp, &devfs_vnodeops, &vp);
  469         if (error != 0) {
  470                 devfs_allocv_drop_refs(1, dmp, de);
  471                 printf("devfs_allocv: failed to allocate new vnode\n");
  472                 return (error);
  473         }
  474 
  475         if (de->de_dirent->d_type == DT_CHR) {
  476                 vp->v_type = VCHR;
  477                 VI_LOCK(vp);
  478                 dev_lock();
  479                 dev_refl(dev);
  480                 /* XXX: v_rdev should be protect by vnode lock */
  481                 vp->v_rdev = dev;
  482                 KASSERT(vp->v_usecount == 1,
  483                     ("%s %d (%d)\n", __func__, __LINE__, vp->v_usecount));
  484                 dev->si_usecount += vp->v_usecount;
  485                 /* Special casing of ttys for deadfs.  Probably redundant. */
  486                 dsw = dev->si_devsw;
  487                 if (dsw != NULL && (dsw->d_flags & D_TTY) != 0)
  488                         vp->v_vflag |= VV_ISTTY;
  489                 dev_unlock();
  490                 VI_UNLOCK(vp);
  491                 if ((dev->si_flags & SI_ETERNAL) != 0)
  492                         vp->v_vflag |= VV_ETERNALDEV;
  493                 vp->v_op = &devfs_specops;
  494         } else if (de->de_dirent->d_type == DT_DIR) {
  495                 vp->v_type = VDIR;
  496         } else if (de->de_dirent->d_type == DT_LNK) {
  497                 vp->v_type = VLNK;
  498         } else {
  499                 vp->v_type = VBAD;
  500         }
  501         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOWITNESS);
  502         VN_LOCK_ASHARE(vp);
  503         mtx_lock(&devfs_de_interlock);
  504         vp->v_data = de;
  505         de->de_vnode = vp;
  506         mtx_unlock(&devfs_de_interlock);
  507         error = insmntque1(vp, mp, devfs_insmntque_dtr, de);
  508         if (error != 0) {
  509                 (void) devfs_allocv_drop_refs(1, dmp, de);
  510                 return (error);
  511         }
  512         if (devfs_allocv_drop_refs(0, dmp, de)) {
  513                 vput(vp);
  514                 return (ENOENT);
  515         }
  516 #ifdef MAC
  517         mac_devfs_vnode_associate(mp, de, vp);
  518 #endif
  519         sx_xunlock(&dmp->dm_lock);
  520         *vpp = vp;
  521         return (0);
  522 }
  523 
  524 static int
  525 devfs_access(struct vop_access_args *ap)
  526 {
  527         struct vnode *vp = ap->a_vp;
  528         struct devfs_dirent *de;
  529         int error;
  530 
  531         de = vp->v_data;
  532         if (vp->v_type == VDIR)
  533                 de = de->de_dir;
  534 
  535         error = vaccess(vp->v_type, de->de_mode, de->de_uid, de->de_gid,
  536             ap->a_accmode, ap->a_cred, NULL);
  537         if (error == 0)
  538                 return (0);
  539         if (error != EACCES)
  540                 return (error);
  541         /* We do, however, allow access to the controlling terminal */
  542         if (!(ap->a_td->td_proc->p_flag & P_CONTROLT))
  543                 return (error);
  544         if (ap->a_td->td_proc->p_session->s_ttydp == de->de_cdp)
  545                 return (0);
  546         return (error);
  547 }
  548 
  549 /* ARGSUSED */
  550 static int
  551 devfs_close(struct vop_close_args *ap)
  552 {
  553         struct vnode *vp = ap->a_vp, *oldvp;
  554         struct thread *td = ap->a_td;
  555         struct cdev *dev = vp->v_rdev;
  556         struct cdevsw *dsw;
  557         int vp_locked, error, ref;
  558 
  559         /*
  560          * XXX: Don't call d_close() if we were called because of
  561          * XXX: insmntque1() failure.
  562          */
  563         if (vp->v_data == NULL)
  564                 return (0);
  565 
  566         /*
  567          * Hack: a tty device that is a controlling terminal
  568          * has a reference from the session structure.
  569          * We cannot easily tell that a character device is
  570          * a controlling terminal, unless it is the closing
  571          * process' controlling terminal.  In that case,
  572          * if the reference count is 2 (this last descriptor
  573          * plus the session), release the reference from the session.
  574          */
  575         oldvp = NULL;
  576         sx_xlock(&proctree_lock);
  577         if (td && vp == td->td_proc->p_session->s_ttyvp) {
  578                 SESS_LOCK(td->td_proc->p_session);
  579                 VI_LOCK(vp);
  580                 if (count_dev(dev) == 2 && (vp->v_iflag & VI_DOOMED) == 0) {
  581                         td->td_proc->p_session->s_ttyvp = NULL;
  582                         td->td_proc->p_session->s_ttydp = NULL;
  583                         oldvp = vp;
  584                 }
  585                 VI_UNLOCK(vp);
  586                 SESS_UNLOCK(td->td_proc->p_session);
  587         }
  588         sx_xunlock(&proctree_lock);
  589         if (oldvp != NULL)
  590                 vrele(oldvp);
  591         /*
  592          * We do not want to really close the device if it
  593          * is still in use unless we are trying to close it
  594          * forcibly. Since every use (buffer, vnode, swap, cmap)
  595          * holds a reference to the vnode, and because we mark
  596          * any other vnodes that alias this device, when the
  597          * sum of the reference counts on all the aliased
  598          * vnodes descends to one, we are on last close.
  599          */
  600         dsw = dev_refthread(dev, &ref);
  601         if (dsw == NULL)
  602                 return (ENXIO);
  603         VI_LOCK(vp);
  604         if (vp->v_iflag & VI_DOOMED) {
  605                 /* Forced close. */
  606         } else if (dsw->d_flags & D_TRACKCLOSE) {
  607                 /* Keep device updated on status. */
  608         } else if (count_dev(dev) > 1) {
  609                 VI_UNLOCK(vp);
  610                 dev_relthread(dev, ref);
  611                 return (0);
  612         }
  613         vholdl(vp);
  614         VI_UNLOCK(vp);
  615         vp_locked = VOP_ISLOCKED(vp);
  616         VOP_UNLOCK(vp, 0);
  617         KASSERT(dev->si_refcount > 0,
  618             ("devfs_close() on un-referenced struct cdev *(%s)", devtoname(dev)));
  619         error = dsw->d_close(dev, ap->a_fflag, S_IFCHR, td);
  620         dev_relthread(dev, ref);
  621         vn_lock(vp, vp_locked | LK_RETRY);
  622         vdrop(vp);
  623         return (error);
  624 }
  625 
  626 static int
  627 devfs_close_f(struct file *fp, struct thread *td)
  628 {
  629         int error;
  630         struct file *fpop;
  631 
  632         /*
  633          * NB: td may be NULL if this descriptor is closed due to
  634          * garbage collection from a closed UNIX domain socket.
  635          */
  636         fpop = curthread->td_fpop;
  637         curthread->td_fpop = fp;
  638         error = vnops.fo_close(fp, td);
  639         curthread->td_fpop = fpop;
  640 
  641         /*
  642          * The f_cdevpriv cannot be assigned non-NULL value while we
  643          * are destroying the file.
  644          */
  645         if (fp->f_cdevpriv != NULL)
  646                 devfs_fpdrop(fp);
  647         return (error);
  648 }
  649 
  650 static int
  651 devfs_fsync(struct vop_fsync_args *ap)
  652 {
  653         int error;
  654         struct bufobj *bo;
  655         struct devfs_dirent *de;
  656 
  657         if (!vn_isdisk(ap->a_vp, &error)) {
  658                 bo = &ap->a_vp->v_bufobj;
  659                 de = ap->a_vp->v_data;
  660                 if (error == ENXIO && bo->bo_dirty.bv_cnt > 0) {
  661                         printf("Device %s went missing before all of the data "
  662                             "could be written to it; expect data loss.\n",
  663                             de->de_dirent->d_name);
  664 
  665                         error = vop_stdfsync(ap);
  666                         if (bo->bo_dirty.bv_cnt != 0 || error != 0)
  667                                 panic("devfs_fsync: vop_stdfsync failed.");
  668                 }
  669 
  670                 return (0);
  671         }
  672 
  673         return (vop_stdfsync(ap));
  674 }
  675 
  676 static int
  677 devfs_getattr(struct vop_getattr_args *ap)
  678 {
  679         struct vnode *vp = ap->a_vp;
  680         struct vattr *vap = ap->a_vap;
  681         int error;
  682         struct devfs_dirent *de;
  683         struct devfs_mount *dmp;
  684         struct cdev *dev;
  685 
  686         error = devfs_populate_vp(vp);
  687         if (error != 0)
  688                 return (error);
  689 
  690         dmp = VFSTODEVFS(vp->v_mount);
  691         sx_xunlock(&dmp->dm_lock);
  692 
  693         de = vp->v_data;
  694         KASSERT(de != NULL, ("Null dirent in devfs_getattr vp=%p", vp));
  695         if (vp->v_type == VDIR) {
  696                 de = de->de_dir;
  697                 KASSERT(de != NULL,
  698                     ("Null dir dirent in devfs_getattr vp=%p", vp));
  699         }
  700         vap->va_uid = de->de_uid;
  701         vap->va_gid = de->de_gid;
  702         vap->va_mode = de->de_mode;
  703         if (vp->v_type == VLNK)
  704                 vap->va_size = strlen(de->de_symlink);
  705         else if (vp->v_type == VDIR)
  706                 vap->va_size = vap->va_bytes = DEV_BSIZE;
  707         else
  708                 vap->va_size = 0;
  709         if (vp->v_type != VDIR)
  710                 vap->va_bytes = 0;
  711         vap->va_blocksize = DEV_BSIZE;
  712         vap->va_type = vp->v_type;
  713 
  714 #define fix(aa)                                                 \
  715         do {                                                    \
  716                 if ((aa).tv_sec <= 3600) {                      \
  717                         (aa).tv_sec = boottime.tv_sec;          \
  718                         (aa).tv_nsec = boottime.tv_usec * 1000; \
  719                 }                                               \
  720         } while (0)
  721 
  722         if (vp->v_type != VCHR)  {
  723                 fix(de->de_atime);
  724                 vap->va_atime = de->de_atime;
  725                 fix(de->de_mtime);
  726                 vap->va_mtime = de->de_mtime;
  727                 fix(de->de_ctime);
  728                 vap->va_ctime = de->de_ctime;
  729         } else {
  730                 dev = vp->v_rdev;
  731                 fix(dev->si_atime);
  732                 vap->va_atime = dev->si_atime;
  733                 fix(dev->si_mtime);
  734                 vap->va_mtime = dev->si_mtime;
  735                 fix(dev->si_ctime);
  736                 vap->va_ctime = dev->si_ctime;
  737 
  738                 vap->va_rdev = cdev2priv(dev)->cdp_inode;
  739         }
  740         vap->va_gen = 0;
  741         vap->va_flags = 0;
  742         vap->va_filerev = 0;
  743         vap->va_nlink = de->de_links;
  744         vap->va_fileid = de->de_inode;
  745 
  746         return (error);
  747 }
  748 
  749 /* ARGSUSED */
  750 static int
  751 devfs_ioctl_f(struct file *fp, u_long com, void *data, struct ucred *cred, struct thread *td)
  752 {
  753         struct cdev *dev;
  754         struct cdevsw *dsw;
  755         struct vnode *vp;
  756         struct vnode *vpold;
  757         int error, i, ref;
  758         const char *p;
  759         struct fiodgname_arg *fgn;
  760         struct file *fpop;
  761 
  762         fpop = td->td_fpop;
  763         error = devfs_fp_check(fp, &dev, &dsw, &ref);
  764         if (error != 0) {
  765                 error = vnops.fo_ioctl(fp, com, data, cred, td);
  766                 return (error);
  767         }
  768 
  769         if (com == FIODTYPE) {
  770                 *(int *)data = dsw->d_flags & D_TYPEMASK;
  771                 td->td_fpop = fpop;
  772                 dev_relthread(dev, ref);
  773                 return (0);
  774         } else if (com == FIODGNAME) {
  775                 fgn = data;
  776                 p = devtoname(dev);
  777                 i = strlen(p) + 1;
  778                 if (i > fgn->len)
  779                         error = EINVAL;
  780                 else
  781                         error = copyout(p, fgn->buf, i);
  782                 td->td_fpop = fpop;
  783                 dev_relthread(dev, ref);
  784                 return (error);
  785         }
  786         error = dsw->d_ioctl(dev, com, data, fp->f_flag, td);
  787         td->td_fpop = NULL;
  788         dev_relthread(dev, ref);
  789         if (error == ENOIOCTL)
  790                 error = ENOTTY;
  791         if (error == 0 && com == TIOCSCTTY) {
  792                 vp = fp->f_vnode;
  793 
  794                 /* Do nothing if reassigning same control tty */
  795                 sx_slock(&proctree_lock);
  796                 if (td->td_proc->p_session->s_ttyvp == vp) {
  797                         sx_sunlock(&proctree_lock);
  798                         return (0);
  799                 }
  800 
  801                 vpold = td->td_proc->p_session->s_ttyvp;
  802                 VREF(vp);
  803                 SESS_LOCK(td->td_proc->p_session);
  804                 td->td_proc->p_session->s_ttyvp = vp;
  805                 td->td_proc->p_session->s_ttydp = cdev2priv(dev);
  806                 SESS_UNLOCK(td->td_proc->p_session);
  807 
  808                 sx_sunlock(&proctree_lock);
  809 
  810                 /* Get rid of reference to old control tty */
  811                 if (vpold)
  812                         vrele(vpold);
  813         }
  814         return (error);
  815 }
  816 
  817 /* ARGSUSED */
  818 static int
  819 devfs_kqfilter_f(struct file *fp, struct knote *kn)
  820 {
  821         struct cdev *dev;
  822         struct cdevsw *dsw;
  823         int error, ref;
  824         struct file *fpop;
  825         struct thread *td;
  826 
  827         td = curthread;
  828         fpop = td->td_fpop;
  829         error = devfs_fp_check(fp, &dev, &dsw, &ref);
  830         if (error)
  831                 return (error);
  832         error = dsw->d_kqfilter(dev, kn);
  833         td->td_fpop = fpop;
  834         dev_relthread(dev, ref);
  835         return (error);
  836 }
  837 
  838 static inline int
  839 devfs_prison_check(struct devfs_dirent *de, struct thread *td)
  840 {
  841         struct cdev_priv *cdp;
  842         struct ucred *dcr;
  843         int error;
  844 
  845         cdp = de->de_cdp;
  846         if (cdp == NULL)
  847                 return (0);
  848         dcr = cdp->cdp_c.si_cred;
  849         if (dcr == NULL)
  850                 return (0);
  851 
  852         error = prison_check(td->td_ucred, dcr);
  853         if (error == 0)
  854                 return (0);
  855         /* We do, however, allow access to the controlling terminal */
  856         if (!(td->td_proc->p_flag & P_CONTROLT))
  857                 return (error);
  858         if (td->td_proc->p_session->s_ttydp == cdp)
  859                 return (0);
  860         return (error);
  861 }
  862 
  863 static int
  864 devfs_lookupx(struct vop_lookup_args *ap, int *dm_unlock)
  865 {
  866         struct componentname *cnp;
  867         struct vnode *dvp, **vpp;
  868         struct thread *td;
  869         struct devfs_dirent *de, *dd;
  870         struct devfs_dirent **dde;
  871         struct devfs_mount *dmp;
  872         struct cdev *cdev;
  873         int error, flags, nameiop, dvplocked;
  874         char specname[SPECNAMELEN + 1], *pname;
  875 
  876         cnp = ap->a_cnp;
  877         vpp = ap->a_vpp;
  878         dvp = ap->a_dvp;
  879         pname = cnp->cn_nameptr;
  880         td = cnp->cn_thread;
  881         flags = cnp->cn_flags;
  882         nameiop = cnp->cn_nameiop;
  883         dmp = VFSTODEVFS(dvp->v_mount);
  884         dd = dvp->v_data;
  885         *vpp = NULLVP;
  886 
  887         if ((flags & ISLASTCN) && nameiop == RENAME)
  888                 return (EOPNOTSUPP);
  889 
  890         if (dvp->v_type != VDIR)
  891                 return (ENOTDIR);
  892 
  893         if ((flags & ISDOTDOT) && (dvp->v_vflag & VV_ROOT))
  894                 return (EIO);
  895 
  896         error = VOP_ACCESS(dvp, VEXEC, cnp->cn_cred, td);
  897         if (error)
  898                 return (error);
  899 
  900         if (cnp->cn_namelen == 1 && *pname == '.') {
  901                 if ((flags & ISLASTCN) && nameiop != LOOKUP)
  902                         return (EINVAL);
  903                 *vpp = dvp;
  904                 VREF(dvp);
  905                 return (0);
  906         }
  907 
  908         if (flags & ISDOTDOT) {
  909                 if ((flags & ISLASTCN) && nameiop != LOOKUP)
  910                         return (EINVAL);
  911                 de = devfs_parent_dirent(dd);
  912                 if (de == NULL)
  913                         return (ENOENT);
  914                 dvplocked = VOP_ISLOCKED(dvp);
  915                 VOP_UNLOCK(dvp, 0);
  916                 error = devfs_allocv(de, dvp->v_mount,
  917                     cnp->cn_lkflags & LK_TYPE_MASK, vpp);
  918                 *dm_unlock = 0;
  919                 vn_lock(dvp, dvplocked | LK_RETRY);
  920                 return (error);
  921         }
  922 
  923         dd = dvp->v_data;
  924         de = devfs_find(dd, cnp->cn_nameptr, cnp->cn_namelen, 0);
  925         while (de == NULL) {    /* While(...) so we can use break */
  926 
  927                 if (nameiop == DELETE)
  928                         return (ENOENT);
  929 
  930                 /*
  931                  * OK, we didn't have an entry for the name we were asked for
  932                  * so we try to see if anybody can create it on demand.
  933                  */
  934                 pname = devfs_fqpn(specname, dmp, dd, cnp);
  935                 if (pname == NULL)
  936                         break;
  937 
  938                 cdev = NULL;
  939                 DEVFS_DMP_HOLD(dmp);
  940                 sx_xunlock(&dmp->dm_lock);
  941                 sx_slock(&clone_drain_lock);
  942                 EVENTHANDLER_INVOKE(dev_clone,
  943                     td->td_ucred, pname, strlen(pname), &cdev);
  944                 sx_sunlock(&clone_drain_lock);
  945 
  946                 if (cdev == NULL)
  947                         sx_xlock(&dmp->dm_lock);
  948                 else if (devfs_populate_vp(dvp) != 0) {
  949                         *dm_unlock = 0;
  950                         sx_xlock(&dmp->dm_lock);
  951                         if (DEVFS_DMP_DROP(dmp)) {
  952                                 sx_xunlock(&dmp->dm_lock);
  953                                 devfs_unmount_final(dmp);
  954                         } else
  955                                 sx_xunlock(&dmp->dm_lock);
  956                         dev_rel(cdev);
  957                         return (ENOENT);
  958                 }
  959                 if (DEVFS_DMP_DROP(dmp)) {
  960                         *dm_unlock = 0;
  961                         sx_xunlock(&dmp->dm_lock);
  962                         devfs_unmount_final(dmp);
  963                         if (cdev != NULL)
  964                                 dev_rel(cdev);
  965                         return (ENOENT);
  966                 }
  967 
  968                 if (cdev == NULL)
  969                         break;
  970 
  971                 dev_lock();
  972                 dde = &cdev2priv(cdev)->cdp_dirents[dmp->dm_idx];
  973                 if (dde != NULL && *dde != NULL)
  974                         de = *dde;
  975                 dev_unlock();
  976                 dev_rel(cdev);
  977                 break;
  978         }
  979 
  980         if (de == NULL || de->de_flags & DE_WHITEOUT) {
  981                 if ((nameiop == CREATE || nameiop == RENAME) &&
  982                     (flags & (LOCKPARENT | WANTPARENT)) && (flags & ISLASTCN)) {
  983                         cnp->cn_flags |= SAVENAME;
  984                         return (EJUSTRETURN);
  985                 }
  986                 return (ENOENT);
  987         }
  988 
  989         if (devfs_prison_check(de, td))
  990                 return (ENOENT);
  991 
  992         if ((cnp->cn_nameiop == DELETE) && (flags & ISLASTCN)) {
  993                 error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, td);
  994                 if (error)
  995                         return (error);
  996                 if (*vpp == dvp) {
  997                         VREF(dvp);
  998                         *vpp = dvp;
  999                         return (0);
 1000                 }
 1001         }
 1002         error = devfs_allocv(de, dvp->v_mount, cnp->cn_lkflags & LK_TYPE_MASK,
 1003             vpp);
 1004         *dm_unlock = 0;
 1005         return (error);
 1006 }
 1007 
 1008 static int
 1009 devfs_lookup(struct vop_lookup_args *ap)
 1010 {
 1011         int j;
 1012         struct devfs_mount *dmp;
 1013         int dm_unlock;
 1014 
 1015         if (devfs_populate_vp(ap->a_dvp) != 0)
 1016                 return (ENOTDIR);
 1017 
 1018         dmp = VFSTODEVFS(ap->a_dvp->v_mount);
 1019         dm_unlock = 1;
 1020         j = devfs_lookupx(ap, &dm_unlock);
 1021         if (dm_unlock == 1)
 1022                 sx_xunlock(&dmp->dm_lock);
 1023         return (j);
 1024 }
 1025 
 1026 static int
 1027 devfs_mknod(struct vop_mknod_args *ap)
 1028 {
 1029         struct componentname *cnp;
 1030         struct vnode *dvp, **vpp;
 1031         struct devfs_dirent *dd, *de;
 1032         struct devfs_mount *dmp;
 1033         int error;
 1034 
 1035         /*
 1036          * The only type of node we should be creating here is a
 1037          * character device, for anything else return EOPNOTSUPP.
 1038          */
 1039         if (ap->a_vap->va_type != VCHR)
 1040                 return (EOPNOTSUPP);
 1041         dvp = ap->a_dvp;
 1042         dmp = VFSTODEVFS(dvp->v_mount);
 1043 
 1044         cnp = ap->a_cnp;
 1045         vpp = ap->a_vpp;
 1046         dd = dvp->v_data;
 1047 
 1048         error = ENOENT;
 1049         sx_xlock(&dmp->dm_lock);
 1050         TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
 1051                 if (cnp->cn_namelen != de->de_dirent->d_namlen)
 1052                         continue;
 1053                 if (de->de_dirent->d_type == DT_CHR &&
 1054                     (de->de_cdp->cdp_flags & CDP_ACTIVE) == 0)
 1055                         continue;
 1056                 if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
 1057                     de->de_dirent->d_namlen) != 0)
 1058                         continue;
 1059                 if (de->de_flags & DE_WHITEOUT)
 1060                         break;
 1061                 goto notfound;
 1062         }
 1063         if (de == NULL)
 1064                 goto notfound;
 1065         de->de_flags &= ~DE_WHITEOUT;
 1066         error = devfs_allocv(de, dvp->v_mount, LK_EXCLUSIVE, vpp);
 1067         return (error);
 1068 notfound:
 1069         sx_xunlock(&dmp->dm_lock);
 1070         return (error);
 1071 }
 1072 
 1073 /* ARGSUSED */
 1074 static int
 1075 devfs_open(struct vop_open_args *ap)
 1076 {
 1077         struct thread *td = ap->a_td;
 1078         struct vnode *vp = ap->a_vp;
 1079         struct cdev *dev = vp->v_rdev;
 1080         struct file *fp = ap->a_fp;
 1081         int error, ref, vlocked;
 1082         struct cdevsw *dsw;
 1083         struct file *fpop;
 1084         struct mtx *mtxp;
 1085 
 1086         if (vp->v_type == VBLK)
 1087                 return (ENXIO);
 1088 
 1089         if (dev == NULL)
 1090                 return (ENXIO);
 1091 
 1092         /* Make this field valid before any I/O in d_open. */
 1093         if (dev->si_iosize_max == 0)
 1094                 dev->si_iosize_max = DFLTPHYS;
 1095 
 1096         dsw = dev_refthread(dev, &ref);
 1097         if (dsw == NULL)
 1098                 return (ENXIO);
 1099         if (fp == NULL && dsw->d_fdopen != NULL) {
 1100                 dev_relthread(dev, ref);
 1101                 return (ENXIO);
 1102         }
 1103 
 1104         vlocked = VOP_ISLOCKED(vp);
 1105         VOP_UNLOCK(vp, 0);
 1106 
 1107         fpop = td->td_fpop;
 1108         td->td_fpop = fp;
 1109         if (fp != NULL) {
 1110                 fp->f_data = dev;
 1111                 fp->f_vnode = vp;
 1112         }
 1113         if (dsw->d_fdopen != NULL)
 1114                 error = dsw->d_fdopen(dev, ap->a_mode, td, fp);
 1115         else
 1116                 error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
 1117         /* Clean up any cdevpriv upon error. */
 1118         if (error != 0)
 1119                 devfs_clear_cdevpriv();
 1120         td->td_fpop = fpop;
 1121 
 1122         vn_lock(vp, vlocked | LK_RETRY);
 1123         dev_relthread(dev, ref);
 1124         if (error != 0) {
 1125                 if (error == ERESTART)
 1126                         error = EINTR;
 1127                 return (error);
 1128         }
 1129 
 1130 #if 0   /* /dev/console */
 1131         KASSERT(fp != NULL, ("Could not vnode bypass device on NULL fp"));
 1132 #else
 1133         if (fp == NULL)
 1134                 return (error);
 1135 #endif
 1136         if (fp->f_ops == &badfileops)
 1137                 finit(fp, fp->f_flag, DTYPE_VNODE, dev, &devfs_ops_f);
 1138         mtxp = mtx_pool_find(mtxpool_sleep, fp);
 1139 
 1140         /*
 1141          * Hint to the dofilewrite() to not force the buffer draining
 1142          * on the writer to the file.  Most likely, the write would
 1143          * not need normal buffers.
 1144          */
 1145         mtx_lock(mtxp);
 1146         fp->f_vnread_flags |= FDEVFS_VNODE;
 1147         mtx_unlock(mtxp);
 1148         return (error);
 1149 }
 1150 
 1151 static int
 1152 devfs_pathconf(struct vop_pathconf_args *ap)
 1153 {
 1154 
 1155         switch (ap->a_name) {
 1156         case _PC_MAC_PRESENT:
 1157 #ifdef MAC
 1158                 /*
 1159                  * If MAC is enabled, devfs automatically supports
 1160                  * trivial non-persistant label storage.
 1161                  */
 1162                 *ap->a_retval = 1;
 1163 #else
 1164                 *ap->a_retval = 0;
 1165 #endif
 1166                 return (0);
 1167         default:
 1168                 return (vop_stdpathconf(ap));
 1169         }
 1170         /* NOTREACHED */
 1171 }
 1172 
 1173 /* ARGSUSED */
 1174 static int
 1175 devfs_poll_f(struct file *fp, int events, struct ucred *cred, struct thread *td)
 1176 {
 1177         struct cdev *dev;
 1178         struct cdevsw *dsw;
 1179         int error, ref;
 1180         struct file *fpop;
 1181 
 1182         fpop = td->td_fpop;
 1183         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1184         if (error != 0) {
 1185                 error = vnops.fo_poll(fp, events, cred, td);
 1186                 return (error);
 1187         }
 1188         error = dsw->d_poll(dev, events, td);
 1189         td->td_fpop = fpop;
 1190         dev_relthread(dev, ref);
 1191         return(error);
 1192 }
 1193 
 1194 /*
 1195  * Print out the contents of a special device vnode.
 1196  */
 1197 static int
 1198 devfs_print(struct vop_print_args *ap)
 1199 {
 1200 
 1201         printf("\tdev %s\n", devtoname(ap->a_vp->v_rdev));
 1202         return (0);
 1203 }
 1204 
 1205 static int
 1206 devfs_read_f(struct file *fp, struct uio *uio, struct ucred *cred,
 1207     int flags, struct thread *td)
 1208 {
 1209         struct cdev *dev;
 1210         int ioflag, error, ref;
 1211         ssize_t resid;
 1212         struct cdevsw *dsw;
 1213         struct file *fpop;
 1214 
 1215         if (uio->uio_resid > DEVFS_IOSIZE_MAX)
 1216                 return (EINVAL);
 1217         fpop = td->td_fpop;
 1218         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1219         if (error != 0) {
 1220                 error = vnops.fo_read(fp, uio, cred, flags, td);
 1221                 return (error);
 1222         }
 1223         resid = uio->uio_resid;
 1224         ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT);
 1225         if (ioflag & O_DIRECT)
 1226                 ioflag |= IO_DIRECT;
 1227 
 1228         foffset_lock_uio(fp, uio, flags | FOF_NOLOCK);
 1229         error = dsw->d_read(dev, uio, ioflag);
 1230         if (uio->uio_resid != resid || (error == 0 && resid != 0))
 1231                 devfs_timestamp(&dev->si_atime);
 1232         td->td_fpop = fpop;
 1233         dev_relthread(dev, ref);
 1234 
 1235         foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF);
 1236         return (error);
 1237 }
 1238 
 1239 static int
 1240 devfs_readdir(struct vop_readdir_args *ap)
 1241 {
 1242         int error;
 1243         struct uio *uio;
 1244         struct dirent *dp;
 1245         struct devfs_dirent *dd;
 1246         struct devfs_dirent *de;
 1247         struct devfs_mount *dmp;
 1248         off_t off;
 1249         int *tmp_ncookies = NULL;
 1250 
 1251         if (ap->a_vp->v_type != VDIR)
 1252                 return (ENOTDIR);
 1253 
 1254         uio = ap->a_uio;
 1255         if (uio->uio_offset < 0)
 1256                 return (EINVAL);
 1257 
 1258         /*
 1259          * XXX: This is a temporary hack to get around this filesystem not
 1260          * supporting cookies. We store the location of the ncookies pointer
 1261          * in a temporary variable before calling vfs_subr.c:vfs_read_dirent()
 1262          * and set the number of cookies to 0. We then set the pointer to
 1263          * NULL so that vfs_read_dirent doesn't try to call realloc() on 
 1264          * ap->a_cookies. Later in this function, we restore the ap->a_ncookies
 1265          * pointer to its original location before returning to the caller.
 1266          */
 1267         if (ap->a_ncookies != NULL) {
 1268                 tmp_ncookies = ap->a_ncookies;
 1269                 *ap->a_ncookies = 0;
 1270                 ap->a_ncookies = NULL;
 1271         }
 1272 
 1273         dmp = VFSTODEVFS(ap->a_vp->v_mount);
 1274         if (devfs_populate_vp(ap->a_vp) != 0) {
 1275                 if (tmp_ncookies != NULL)
 1276                         ap->a_ncookies = tmp_ncookies;
 1277                 return (EIO);
 1278         }
 1279         error = 0;
 1280         de = ap->a_vp->v_data;
 1281         off = 0;
 1282         TAILQ_FOREACH(dd, &de->de_dlist, de_list) {
 1283                 KASSERT(dd->de_cdp != (void *)0xdeadc0de, ("%s %d\n", __func__, __LINE__));
 1284                 if (dd->de_flags & (DE_COVERED | DE_WHITEOUT))
 1285                         continue;
 1286                 if (devfs_prison_check(dd, uio->uio_td))
 1287                         continue;
 1288                 if (dd->de_dirent->d_type == DT_DIR)
 1289                         de = dd->de_dir;
 1290                 else
 1291                         de = dd;
 1292                 dp = dd->de_dirent;
 1293                 if (dp->d_reclen > uio->uio_resid)
 1294                         break;
 1295                 dp->d_fileno = de->de_inode;
 1296                 if (off >= uio->uio_offset) {
 1297                         error = vfs_read_dirent(ap, dp, off);
 1298                         if (error)
 1299                                 break;
 1300                 }
 1301                 off += dp->d_reclen;
 1302         }
 1303         sx_xunlock(&dmp->dm_lock);
 1304         uio->uio_offset = off;
 1305 
 1306         /*
 1307          * Restore ap->a_ncookies if it wasn't originally NULL in the first
 1308          * place.
 1309          */
 1310         if (tmp_ncookies != NULL)
 1311                 ap->a_ncookies = tmp_ncookies;
 1312 
 1313         return (error);
 1314 }
 1315 
 1316 static int
 1317 devfs_readlink(struct vop_readlink_args *ap)
 1318 {
 1319         struct devfs_dirent *de;
 1320 
 1321         de = ap->a_vp->v_data;
 1322         return (uiomove(de->de_symlink, strlen(de->de_symlink), ap->a_uio));
 1323 }
 1324 
 1325 static int
 1326 devfs_reclaim(struct vop_reclaim_args *ap)
 1327 {
 1328         struct vnode *vp;
 1329         struct devfs_dirent *de;
 1330 
 1331         vp = ap->a_vp;
 1332         mtx_lock(&devfs_de_interlock);
 1333         de = vp->v_data;
 1334         if (de != NULL) {
 1335                 de->de_vnode = NULL;
 1336                 vp->v_data = NULL;
 1337         }
 1338         mtx_unlock(&devfs_de_interlock);
 1339         vnode_destroy_vobject(vp);
 1340         return (0);
 1341 }
 1342 
 1343 static int
 1344 devfs_reclaim_vchr(struct vop_reclaim_args *ap)
 1345 {
 1346         struct vnode *vp;
 1347         struct cdev *dev;
 1348 
 1349         vp = ap->a_vp;
 1350         MPASS(vp->v_type == VCHR);
 1351 
 1352         devfs_reclaim(ap);
 1353 
 1354         VI_LOCK(vp);
 1355         dev_lock();
 1356         dev = vp->v_rdev;
 1357         vp->v_rdev = NULL;
 1358         if (dev != NULL)
 1359                 dev->si_usecount -= vp->v_usecount;
 1360         dev_unlock();
 1361         VI_UNLOCK(vp);
 1362         if (dev != NULL)
 1363                 dev_rel(dev);
 1364         return (0);
 1365 }
 1366 
 1367 static int
 1368 devfs_remove(struct vop_remove_args *ap)
 1369 {
 1370         struct vnode *dvp = ap->a_dvp;
 1371         struct vnode *vp = ap->a_vp;
 1372         struct devfs_dirent *dd;
 1373         struct devfs_dirent *de, *de_covered;
 1374         struct devfs_mount *dmp = VFSTODEVFS(vp->v_mount);
 1375 
 1376         ASSERT_VOP_ELOCKED(dvp, "devfs_remove");
 1377         ASSERT_VOP_ELOCKED(vp, "devfs_remove");
 1378 
 1379         sx_xlock(&dmp->dm_lock);
 1380         dd = ap->a_dvp->v_data;
 1381         de = vp->v_data;
 1382         if (de->de_cdp == NULL) {
 1383                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
 1384                 if (de->de_dirent->d_type == DT_LNK) {
 1385                         de_covered = devfs_find(dd, de->de_dirent->d_name,
 1386                             de->de_dirent->d_namlen, 0);
 1387                         if (de_covered != NULL)
 1388                                 de_covered->de_flags &= ~DE_COVERED;
 1389                 }
 1390                 /* We need to unlock dvp because devfs_delete() may lock it. */
 1391                 VOP_UNLOCK(vp, 0);
 1392                 if (dvp != vp)
 1393                         VOP_UNLOCK(dvp, 0);
 1394                 devfs_delete(dmp, de, 0);
 1395                 sx_xunlock(&dmp->dm_lock);
 1396                 if (dvp != vp)
 1397                         vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
 1398                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1399         } else {
 1400                 de->de_flags |= DE_WHITEOUT;
 1401                 sx_xunlock(&dmp->dm_lock);
 1402         }
 1403         return (0);
 1404 }
 1405 
 1406 /*
 1407  * Revoke is called on a tty when a terminal session ends.  The vnode
 1408  * is orphaned by setting v_op to deadfs so we need to let go of it
 1409  * as well so that we create a new one next time around.
 1410  *
 1411  */
 1412 static int
 1413 devfs_revoke(struct vop_revoke_args *ap)
 1414 {
 1415         struct vnode *vp = ap->a_vp, *vp2;
 1416         struct cdev *dev;
 1417         struct cdev_priv *cdp;
 1418         struct devfs_dirent *de;
 1419         u_int i;
 1420 
 1421         KASSERT((ap->a_flags & REVOKEALL) != 0, ("devfs_revoke !REVOKEALL"));
 1422 
 1423         dev = vp->v_rdev;
 1424         cdp = cdev2priv(dev);
 1425  
 1426         dev_lock();
 1427         cdp->cdp_inuse++;
 1428         dev_unlock();
 1429 
 1430         vhold(vp);
 1431         vgone(vp);
 1432         vdrop(vp);
 1433 
 1434         VOP_UNLOCK(vp,0);
 1435  loop:
 1436         for (;;) {
 1437                 mtx_lock(&devfs_de_interlock);
 1438                 dev_lock();
 1439                 vp2 = NULL;
 1440                 for (i = 0; i <= cdp->cdp_maxdirent; i++) {
 1441                         de = cdp->cdp_dirents[i];
 1442                         if (de == NULL)
 1443                                 continue;
 1444 
 1445                         vp2 = de->de_vnode;
 1446                         if (vp2 != NULL) {
 1447                                 dev_unlock();
 1448                                 VI_LOCK(vp2);
 1449                                 mtx_unlock(&devfs_de_interlock);
 1450                                 if (vget(vp2, LK_EXCLUSIVE | LK_INTERLOCK,
 1451                                     curthread))
 1452                                         goto loop;
 1453                                 vhold(vp2);
 1454                                 vgone(vp2);
 1455                                 vdrop(vp2);
 1456                                 vput(vp2);
 1457                                 break;
 1458                         } 
 1459                 }
 1460                 if (vp2 != NULL) {
 1461                         continue;
 1462                 }
 1463                 dev_unlock();
 1464                 mtx_unlock(&devfs_de_interlock);
 1465                 break;
 1466         }
 1467         dev_lock();
 1468         cdp->cdp_inuse--;
 1469         if (!(cdp->cdp_flags & CDP_ACTIVE) && cdp->cdp_inuse == 0) {
 1470                 TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
 1471                 dev_unlock();
 1472                 dev_rel(&cdp->cdp_c);
 1473         } else
 1474                 dev_unlock();
 1475 
 1476         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1477         return (0);
 1478 }
 1479 
 1480 static int
 1481 devfs_rioctl(struct vop_ioctl_args *ap)
 1482 {
 1483         struct vnode *vp;
 1484         struct devfs_mount *dmp;
 1485         int error;
 1486 
 1487         vp = ap->a_vp;
 1488         vn_lock(vp, LK_SHARED | LK_RETRY);
 1489         if (vp->v_iflag & VI_DOOMED) {
 1490                 VOP_UNLOCK(vp, 0);
 1491                 return (EBADF);
 1492         }
 1493         dmp = VFSTODEVFS(vp->v_mount);
 1494         sx_xlock(&dmp->dm_lock);
 1495         VOP_UNLOCK(vp, 0);
 1496         DEVFS_DMP_HOLD(dmp);
 1497         devfs_populate(dmp);
 1498         if (DEVFS_DMP_DROP(dmp)) {
 1499                 sx_xunlock(&dmp->dm_lock);
 1500                 devfs_unmount_final(dmp);
 1501                 return (ENOENT);
 1502         }
 1503         error = devfs_rules_ioctl(dmp, ap->a_command, ap->a_data, ap->a_td);
 1504         sx_xunlock(&dmp->dm_lock);
 1505         return (error);
 1506 }
 1507 
 1508 static int
 1509 devfs_rread(struct vop_read_args *ap)
 1510 {
 1511 
 1512         if (ap->a_vp->v_type != VDIR)
 1513                 return (EINVAL);
 1514         return (VOP_READDIR(ap->a_vp, ap->a_uio, ap->a_cred, NULL, NULL, NULL));
 1515 }
 1516 
 1517 static int
 1518 devfs_setattr(struct vop_setattr_args *ap)
 1519 {
 1520         struct devfs_dirent *de;
 1521         struct vattr *vap;
 1522         struct vnode *vp;
 1523         struct thread *td;
 1524         int c, error;
 1525         uid_t uid;
 1526         gid_t gid;
 1527 
 1528         vap = ap->a_vap;
 1529         vp = ap->a_vp;
 1530         td = curthread;
 1531         if ((vap->va_type != VNON) ||
 1532             (vap->va_nlink != VNOVAL) ||
 1533             (vap->va_fsid != VNOVAL) ||
 1534             (vap->va_fileid != VNOVAL) ||
 1535             (vap->va_blocksize != VNOVAL) ||
 1536             (vap->va_flags != VNOVAL && vap->va_flags != 0) ||
 1537             (vap->va_rdev != VNOVAL) ||
 1538             ((int)vap->va_bytes != VNOVAL) ||
 1539             (vap->va_gen != VNOVAL)) {
 1540                 return (EINVAL);
 1541         }
 1542 
 1543         error = devfs_populate_vp(vp);
 1544         if (error != 0)
 1545                 return (error);
 1546 
 1547         de = vp->v_data;
 1548         if (vp->v_type == VDIR)
 1549                 de = de->de_dir;
 1550 
 1551         c = 0;
 1552         if (vap->va_uid == (uid_t)VNOVAL)
 1553                 uid = de->de_uid;
 1554         else
 1555                 uid = vap->va_uid;
 1556         if (vap->va_gid == (gid_t)VNOVAL)
 1557                 gid = de->de_gid;
 1558         else
 1559                 gid = vap->va_gid;
 1560         if (uid != de->de_uid || gid != de->de_gid) {
 1561                 if ((ap->a_cred->cr_uid != de->de_uid) || uid != de->de_uid ||
 1562                     (gid != de->de_gid && !groupmember(gid, ap->a_cred))) {
 1563                         error = priv_check(td, PRIV_VFS_CHOWN);
 1564                         if (error != 0)
 1565                                 goto ret;
 1566                 }
 1567                 de->de_uid = uid;
 1568                 de->de_gid = gid;
 1569                 c = 1;
 1570         }
 1571 
 1572         if (vap->va_mode != (mode_t)VNOVAL) {
 1573                 if (ap->a_cred->cr_uid != de->de_uid) {
 1574                         error = priv_check(td, PRIV_VFS_ADMIN);
 1575                         if (error != 0)
 1576                                 goto ret;
 1577                 }
 1578                 de->de_mode = vap->va_mode;
 1579                 c = 1;
 1580         }
 1581 
 1582         if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
 1583                 error = vn_utimes_perm(vp, vap, ap->a_cred, td);
 1584                 if (error != 0)
 1585                         goto ret;
 1586                 if (vap->va_atime.tv_sec != VNOVAL) {
 1587                         if (vp->v_type == VCHR)
 1588                                 vp->v_rdev->si_atime = vap->va_atime;
 1589                         else
 1590                                 de->de_atime = vap->va_atime;
 1591                 }
 1592                 if (vap->va_mtime.tv_sec != VNOVAL) {
 1593                         if (vp->v_type == VCHR)
 1594                                 vp->v_rdev->si_mtime = vap->va_mtime;
 1595                         else
 1596                                 de->de_mtime = vap->va_mtime;
 1597                 }
 1598                 c = 1;
 1599         }
 1600 
 1601         if (c) {
 1602                 if (vp->v_type == VCHR)
 1603                         vfs_timestamp(&vp->v_rdev->si_ctime);
 1604                 else
 1605                         vfs_timestamp(&de->de_mtime);
 1606         }
 1607 
 1608 ret:
 1609         sx_xunlock(&VFSTODEVFS(vp->v_mount)->dm_lock);
 1610         return (error);
 1611 }
 1612 
 1613 #ifdef MAC
 1614 static int
 1615 devfs_setlabel(struct vop_setlabel_args *ap)
 1616 {
 1617         struct vnode *vp;
 1618         struct devfs_dirent *de;
 1619 
 1620         vp = ap->a_vp;
 1621         de = vp->v_data;
 1622 
 1623         mac_vnode_relabel(ap->a_cred, vp, ap->a_label);
 1624         mac_devfs_update(vp->v_mount, de, vp);
 1625 
 1626         return (0);
 1627 }
 1628 #endif
 1629 
 1630 static int
 1631 devfs_stat_f(struct file *fp, struct stat *sb, struct ucred *cred, struct thread *td)
 1632 {
 1633 
 1634         return (vnops.fo_stat(fp, sb, cred, td));
 1635 }
 1636 
 1637 static int
 1638 devfs_symlink(struct vop_symlink_args *ap)
 1639 {
 1640         int i, error;
 1641         struct devfs_dirent *dd;
 1642         struct devfs_dirent *de, *de_covered, *de_dotdot;
 1643         struct devfs_mount *dmp;
 1644 
 1645         error = priv_check(curthread, PRIV_DEVFS_SYMLINK);
 1646         if (error)
 1647                 return(error);
 1648         dmp = VFSTODEVFS(ap->a_dvp->v_mount);
 1649         if (devfs_populate_vp(ap->a_dvp) != 0)
 1650                 return (ENOENT);
 1651 
 1652         dd = ap->a_dvp->v_data;
 1653         de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen);
 1654         de->de_flags = DE_USER;
 1655         de->de_uid = 0;
 1656         de->de_gid = 0;
 1657         de->de_mode = 0755;
 1658         de->de_inode = alloc_unr(devfs_inos);
 1659         de->de_dir = dd;
 1660         de->de_dirent->d_type = DT_LNK;
 1661         i = strlen(ap->a_target) + 1;
 1662         de->de_symlink = malloc(i, M_DEVFS, M_WAITOK);
 1663         bcopy(ap->a_target, de->de_symlink, i);
 1664 #ifdef MAC
 1665         mac_devfs_create_symlink(ap->a_cnp->cn_cred, dmp->dm_mount, dd, de);
 1666 #endif
 1667         de_covered = devfs_find(dd, de->de_dirent->d_name,
 1668             de->de_dirent->d_namlen, 0);
 1669         if (de_covered != NULL) {
 1670                 if ((de_covered->de_flags & DE_USER) != 0) {
 1671                         devfs_delete(dmp, de, DEVFS_DEL_NORECURSE);
 1672                         sx_xunlock(&dmp->dm_lock);
 1673                         return (EEXIST);
 1674                 }
 1675                 KASSERT((de_covered->de_flags & DE_COVERED) == 0,
 1676                     ("devfs_symlink: entry %p already covered", de_covered));
 1677                 de_covered->de_flags |= DE_COVERED;
 1678         }
 1679 
 1680         de_dotdot = TAILQ_FIRST(&dd->de_dlist);         /* "." */
 1681         de_dotdot = TAILQ_NEXT(de_dotdot, de_list);     /* ".." */
 1682         TAILQ_INSERT_AFTER(&dd->de_dlist, de_dotdot, de, de_list);
 1683         devfs_dir_ref_de(dmp, dd);
 1684         devfs_rules_apply(dmp, de);
 1685 
 1686         return (devfs_allocv(de, ap->a_dvp->v_mount, LK_EXCLUSIVE, ap->a_vpp));
 1687 }
 1688 
 1689 static int
 1690 devfs_truncate_f(struct file *fp, off_t length, struct ucred *cred, struct thread *td)
 1691 {
 1692 
 1693         return (vnops.fo_truncate(fp, length, cred, td));
 1694 }
 1695 
 1696 static int
 1697 devfs_write_f(struct file *fp, struct uio *uio, struct ucred *cred,
 1698     int flags, struct thread *td)
 1699 {
 1700         struct cdev *dev;
 1701         int error, ioflag, ref;
 1702         ssize_t resid;
 1703         struct cdevsw *dsw;
 1704         struct file *fpop;
 1705 
 1706         if (uio->uio_resid > DEVFS_IOSIZE_MAX)
 1707                 return (EINVAL);
 1708         fpop = td->td_fpop;
 1709         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1710         if (error != 0) {
 1711                 error = vnops.fo_write(fp, uio, cred, flags, td);
 1712                 return (error);
 1713         }
 1714         KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", uio->uio_td, td));
 1715         ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT | O_FSYNC);
 1716         if (ioflag & O_DIRECT)
 1717                 ioflag |= IO_DIRECT;
 1718         foffset_lock_uio(fp, uio, flags | FOF_NOLOCK);
 1719 
 1720         resid = uio->uio_resid;
 1721 
 1722         error = dsw->d_write(dev, uio, ioflag);
 1723         if (uio->uio_resid != resid || (error == 0 && resid != 0)) {
 1724                 devfs_timestamp(&dev->si_ctime);
 1725                 dev->si_mtime = dev->si_ctime;
 1726         }
 1727         td->td_fpop = fpop;
 1728         dev_relthread(dev, ref);
 1729 
 1730         foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF);
 1731         return (error);
 1732 }
 1733 
 1734 dev_t
 1735 dev2udev(struct cdev *x)
 1736 {
 1737         if (x == NULL)
 1738                 return (NODEV);
 1739         return (cdev2priv(x)->cdp_inode);
 1740 }
 1741 
 1742 static struct fileops devfs_ops_f = {
 1743         .fo_read =      devfs_read_f,
 1744         .fo_write =     devfs_write_f,
 1745         .fo_truncate =  devfs_truncate_f,
 1746         .fo_ioctl =     devfs_ioctl_f,
 1747         .fo_poll =      devfs_poll_f,
 1748         .fo_kqfilter =  devfs_kqfilter_f,
 1749         .fo_stat =      devfs_stat_f,
 1750         .fo_close =     devfs_close_f,
 1751         .fo_chmod =     vn_chmod,
 1752         .fo_chown =     vn_chown,
 1753         .fo_sendfile =  vn_sendfile,
 1754         .fo_seek =      vn_seek,
 1755         .fo_flags =     DFLAG_PASSABLE | DFLAG_SEEKABLE
 1756 };
 1757 
 1758 static struct vop_vector devfs_vnodeops = {
 1759         .vop_default =          &default_vnodeops,
 1760 
 1761         .vop_access =           devfs_access,
 1762         .vop_getattr =          devfs_getattr,
 1763         .vop_ioctl =            devfs_rioctl,
 1764         .vop_lookup =           devfs_lookup,
 1765         .vop_mknod =            devfs_mknod,
 1766         .vop_pathconf =         devfs_pathconf,
 1767         .vop_read =             devfs_rread,
 1768         .vop_readdir =          devfs_readdir,
 1769         .vop_readlink =         devfs_readlink,
 1770         .vop_reclaim =          devfs_reclaim,
 1771         .vop_remove =           devfs_remove,
 1772         .vop_revoke =           devfs_revoke,
 1773         .vop_setattr =          devfs_setattr,
 1774 #ifdef MAC
 1775         .vop_setlabel =         devfs_setlabel,
 1776 #endif
 1777         .vop_symlink =          devfs_symlink,
 1778         .vop_vptocnp =          devfs_vptocnp,
 1779 };
 1780 
 1781 static struct vop_vector devfs_specops = {
 1782         .vop_default =          &default_vnodeops,
 1783 
 1784         .vop_access =           devfs_access,
 1785         .vop_bmap =             VOP_PANIC,
 1786         .vop_close =            devfs_close,
 1787         .vop_create =           VOP_PANIC,
 1788         .vop_fsync =            devfs_fsync,
 1789         .vop_getattr =          devfs_getattr,
 1790         .vop_link =             VOP_PANIC,
 1791         .vop_mkdir =            VOP_PANIC,
 1792         .vop_mknod =            VOP_PANIC,
 1793         .vop_open =             devfs_open,
 1794         .vop_pathconf =         devfs_pathconf,
 1795         .vop_poll =             dead_poll,
 1796         .vop_print =            devfs_print,
 1797         .vop_read =             dead_read,
 1798         .vop_readdir =          VOP_PANIC,
 1799         .vop_readlink =         VOP_PANIC,
 1800         .vop_reallocblks =      VOP_PANIC,
 1801         .vop_reclaim =          devfs_reclaim_vchr,
 1802         .vop_remove =           devfs_remove,
 1803         .vop_rename =           VOP_PANIC,
 1804         .vop_revoke =           devfs_revoke,
 1805         .vop_rmdir =            VOP_PANIC,
 1806         .vop_setattr =          devfs_setattr,
 1807 #ifdef MAC
 1808         .vop_setlabel =         devfs_setlabel,
 1809 #endif
 1810         .vop_strategy =         VOP_PANIC,
 1811         .vop_symlink =          VOP_PANIC,
 1812         .vop_vptocnp =          devfs_vptocnp,
 1813         .vop_write =            dead_write,
 1814 };
 1815 
 1816 /*
 1817  * Our calling convention to the device drivers used to be that we passed
 1818  * vnode.h IO_* flags to read()/write(), but we're moving to fcntl.h O_ 
 1819  * flags instead since that's what open(), close() and ioctl() takes and
 1820  * we don't really want vnode.h in device drivers.
 1821  * We solved the source compatibility by redefining some vnode flags to
 1822  * be the same as the fcntl ones and by sending down the bitwise OR of
 1823  * the respective fcntl/vnode flags.  These CTASSERTS make sure nobody
 1824  * pulls the rug out under this.
 1825  */
 1826 CTASSERT(O_NONBLOCK == IO_NDELAY);
 1827 CTASSERT(O_FSYNC == IO_SYNC);

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