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/10.0/sys/fs/devfs/devfs_vnops.c 257122 2013-10-25 16:33:24Z 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/time.h>
   61 #include <sys/ttycom.h>
   62 #include <sys/unistd.h>
   63 #include <sys/vnode.h>
   64 
   65 static struct vop_vector devfs_vnodeops;
   66 static struct vop_vector devfs_specops;
   67 static struct fileops devfs_ops_f;
   68 
   69 #include <fs/devfs/devfs.h>
   70 #include <fs/devfs/devfs_int.h>
   71 
   72 #include <security/mac/mac_framework.h>
   73 
   74 static MALLOC_DEFINE(M_CDEVPDATA, "DEVFSP", "Metainfo for cdev-fp data");
   75 
   76 struct mtx      devfs_de_interlock;
   77 MTX_SYSINIT(devfs_de_interlock, &devfs_de_interlock, "devfs interlock", MTX_DEF);
   78 struct sx       clone_drain_lock;
   79 SX_SYSINIT(clone_drain_lock, &clone_drain_lock, "clone events drain lock");
   80 struct mtx      cdevpriv_mtx;
   81 MTX_SYSINIT(cdevpriv_mtx, &cdevpriv_mtx, "cdevpriv lock", MTX_DEF);
   82 
   83 static int
   84 devfs_fp_check(struct file *fp, struct cdev **devp, struct cdevsw **dswp,
   85     int *ref)
   86 {
   87 
   88         *dswp = devvn_refthread(fp->f_vnode, devp, ref);
   89         if (*devp != fp->f_data) {
   90                 if (*dswp != NULL)
   91                         dev_relthread(*devp, *ref);
   92                 return (ENXIO);
   93         }
   94         KASSERT((*devp)->si_refcount > 0,
   95             ("devfs: un-referenced struct cdev *(%s)", devtoname(*devp)));
   96         if (*dswp == NULL)
   97                 return (ENXIO);
   98         curthread->td_fpop = fp;
   99         return (0);
  100 }
  101 
  102 int
  103 devfs_get_cdevpriv(void **datap)
  104 {
  105         struct file *fp;
  106         struct cdev_privdata *p;
  107         int error;
  108 
  109         fp = curthread->td_fpop;
  110         if (fp == NULL)
  111                 return (EBADF);
  112         p = fp->f_cdevpriv;
  113         if (p != NULL) {
  114                 error = 0;
  115                 *datap = p->cdpd_data;
  116         } else
  117                 error = ENOENT;
  118         return (error);
  119 }
  120 
  121 int
  122 devfs_set_cdevpriv(void *priv, cdevpriv_dtr_t priv_dtr)
  123 {
  124         struct file *fp;
  125         struct cdev_priv *cdp;
  126         struct cdev_privdata *p;
  127         int error;
  128 
  129         fp = curthread->td_fpop;
  130         if (fp == NULL)
  131                 return (ENOENT);
  132         cdp = cdev2priv((struct cdev *)fp->f_data);
  133         p = malloc(sizeof(struct cdev_privdata), M_CDEVPDATA, M_WAITOK);
  134         p->cdpd_data = priv;
  135         p->cdpd_dtr = priv_dtr;
  136         p->cdpd_fp = fp;
  137         mtx_lock(&cdevpriv_mtx);
  138         if (fp->f_cdevpriv == NULL) {
  139                 LIST_INSERT_HEAD(&cdp->cdp_fdpriv, p, cdpd_list);
  140                 fp->f_cdevpriv = p;
  141                 mtx_unlock(&cdevpriv_mtx);
  142                 error = 0;
  143         } else {
  144                 mtx_unlock(&cdevpriv_mtx);
  145                 free(p, M_CDEVPDATA);
  146                 error = EBUSY;
  147         }
  148         return (error);
  149 }
  150 
  151 void
  152 devfs_destroy_cdevpriv(struct cdev_privdata *p)
  153 {
  154 
  155         mtx_assert(&cdevpriv_mtx, MA_OWNED);
  156         p->cdpd_fp->f_cdevpriv = NULL;
  157         LIST_REMOVE(p, cdpd_list);
  158         mtx_unlock(&cdevpriv_mtx);
  159         (p->cdpd_dtr)(p->cdpd_data);
  160         free(p, M_CDEVPDATA);
  161 }
  162 
  163 void
  164 devfs_fpdrop(struct file *fp)
  165 {
  166         struct cdev_privdata *p;
  167 
  168         mtx_lock(&cdevpriv_mtx);
  169         if ((p = fp->f_cdevpriv) == NULL) {
  170                 mtx_unlock(&cdevpriv_mtx);
  171                 return;
  172         }
  173         devfs_destroy_cdevpriv(p);
  174 }
  175 
  176 void
  177 devfs_clear_cdevpriv(void)
  178 {
  179         struct file *fp;
  180 
  181         fp = curthread->td_fpop;
  182         if (fp == NULL)
  183                 return;
  184         devfs_fpdrop(fp);
  185 }
  186 
  187 /*
  188  * On success devfs_populate_vp() returns with dmp->dm_lock held.
  189  */
  190 static int
  191 devfs_populate_vp(struct vnode *vp)
  192 {
  193         struct devfs_dirent *de;
  194         struct devfs_mount *dmp;
  195         int locked;
  196 
  197         ASSERT_VOP_LOCKED(vp, "devfs_populate_vp");
  198 
  199         dmp = VFSTODEVFS(vp->v_mount);
  200         locked = VOP_ISLOCKED(vp);
  201 
  202         sx_xlock(&dmp->dm_lock);
  203         DEVFS_DMP_HOLD(dmp);
  204 
  205         /* Can't call devfs_populate() with the vnode lock held. */
  206         VOP_UNLOCK(vp, 0);
  207         devfs_populate(dmp);
  208 
  209         sx_xunlock(&dmp->dm_lock);
  210         vn_lock(vp, locked | LK_RETRY);
  211         sx_xlock(&dmp->dm_lock);
  212         if (DEVFS_DMP_DROP(dmp)) {
  213                 sx_xunlock(&dmp->dm_lock);
  214                 devfs_unmount_final(dmp);
  215                 return (EBADF);
  216         }
  217         if ((vp->v_iflag & VI_DOOMED) != 0) {
  218                 sx_xunlock(&dmp->dm_lock);
  219                 return (EBADF);
  220         }
  221         de = vp->v_data;
  222         KASSERT(de != NULL,
  223             ("devfs_populate_vp: vp->v_data == NULL but vnode not doomed"));
  224         if ((de->de_flags & DE_DOOMED) != 0) {
  225                 sx_xunlock(&dmp->dm_lock);
  226                 return (EBADF);
  227         }
  228 
  229         return (0);
  230 }
  231 
  232 static int
  233 devfs_vptocnp(struct vop_vptocnp_args *ap)
  234 {
  235         struct vnode *vp = ap->a_vp;
  236         struct vnode **dvp = ap->a_vpp;
  237         struct devfs_mount *dmp;
  238         char *buf = ap->a_buf;
  239         int *buflen = ap->a_buflen;
  240         struct devfs_dirent *dd, *de;
  241         int i, error;
  242 
  243         dmp = VFSTODEVFS(vp->v_mount);
  244 
  245         error = devfs_populate_vp(vp);
  246         if (error != 0)
  247                 return (error);
  248 
  249         i = *buflen;
  250         dd = vp->v_data;
  251 
  252         if (vp->v_type == VCHR) {
  253                 i -= strlen(dd->de_cdp->cdp_c.si_name);
  254                 if (i < 0) {
  255                         error = ENOMEM;
  256                         goto finished;
  257                 }
  258                 bcopy(dd->de_cdp->cdp_c.si_name, buf + i,
  259                     strlen(dd->de_cdp->cdp_c.si_name));
  260                 de = dd->de_dir;
  261         } else if (vp->v_type == VDIR) {
  262                 if (dd == dmp->dm_rootdir) {
  263                         *dvp = vp;
  264                         vref(*dvp);
  265                         goto finished;
  266                 }
  267                 i -= dd->de_dirent->d_namlen;
  268                 if (i < 0) {
  269                         error = ENOMEM;
  270                         goto finished;
  271                 }
  272                 bcopy(dd->de_dirent->d_name, buf + i,
  273                     dd->de_dirent->d_namlen);
  274                 de = dd;
  275         } else {
  276                 error = ENOENT;
  277                 goto finished;
  278         }
  279         *buflen = i;
  280         de = devfs_parent_dirent(de);
  281         if (de == NULL) {
  282                 error = ENOENT;
  283                 goto finished;
  284         }
  285         mtx_lock(&devfs_de_interlock);
  286         *dvp = de->de_vnode;
  287         if (*dvp != NULL) {
  288                 VI_LOCK(*dvp);
  289                 mtx_unlock(&devfs_de_interlock);
  290                 vholdl(*dvp);
  291                 VI_UNLOCK(*dvp);
  292                 vref(*dvp);
  293                 vdrop(*dvp);
  294         } else {
  295                 mtx_unlock(&devfs_de_interlock);
  296                 error = ENOENT;
  297         }
  298 finished:
  299         sx_xunlock(&dmp->dm_lock);
  300         return (error);
  301 }
  302 
  303 /*
  304  * Construct the fully qualified path name relative to the mountpoint.
  305  * If a NULL cnp is provided, no '/' is appended to the resulting path.
  306  */
  307 char *
  308 devfs_fqpn(char *buf, struct devfs_mount *dmp, struct devfs_dirent *dd,
  309     struct componentname *cnp)
  310 {
  311         int i;
  312         struct devfs_dirent *de;
  313 
  314         sx_assert(&dmp->dm_lock, SA_LOCKED);
  315 
  316         i = SPECNAMELEN;
  317         buf[i] = '\0';
  318         if (cnp != NULL)
  319                 i -= cnp->cn_namelen;
  320         if (i < 0)
  321                  return (NULL);
  322         if (cnp != NULL)
  323                 bcopy(cnp->cn_nameptr, buf + i, cnp->cn_namelen);
  324         de = dd;
  325         while (de != dmp->dm_rootdir) {
  326                 if (cnp != NULL || i < SPECNAMELEN) {
  327                         i--;
  328                         if (i < 0)
  329                                  return (NULL);
  330                         buf[i] = '/';
  331                 }
  332                 i -= de->de_dirent->d_namlen;
  333                 if (i < 0)
  334                          return (NULL);
  335                 bcopy(de->de_dirent->d_name, buf + i,
  336                     de->de_dirent->d_namlen);
  337                 de = devfs_parent_dirent(de);
  338                 if (de == NULL)
  339                         return (NULL);
  340         }
  341         return (buf + i);
  342 }
  343 
  344 static int
  345 devfs_allocv_drop_refs(int drop_dm_lock, struct devfs_mount *dmp,
  346         struct devfs_dirent *de)
  347 {
  348         int not_found;
  349 
  350         not_found = 0;
  351         if (de->de_flags & DE_DOOMED)
  352                 not_found = 1;
  353         if (DEVFS_DE_DROP(de)) {
  354                 KASSERT(not_found == 1, ("DEVFS de dropped but not doomed"));
  355                 devfs_dirent_free(de);
  356         }
  357         if (DEVFS_DMP_DROP(dmp)) {
  358                 KASSERT(not_found == 1,
  359                         ("DEVFS mount struct freed before dirent"));
  360                 not_found = 2;
  361                 sx_xunlock(&dmp->dm_lock);
  362                 devfs_unmount_final(dmp);
  363         }
  364         if (not_found == 1 || (drop_dm_lock && not_found != 2))
  365                 sx_unlock(&dmp->dm_lock);
  366         return (not_found);
  367 }
  368 
  369 static void
  370 devfs_insmntque_dtr(struct vnode *vp, void *arg)
  371 {
  372         struct devfs_dirent *de;
  373 
  374         de = (struct devfs_dirent *)arg;
  375         mtx_lock(&devfs_de_interlock);
  376         vp->v_data = NULL;
  377         de->de_vnode = NULL;
  378         mtx_unlock(&devfs_de_interlock);
  379         vgone(vp);
  380         vput(vp);
  381 }
  382 
  383 /*
  384  * devfs_allocv shall be entered with dmp->dm_lock held, and it drops
  385  * it on return.
  386  */
  387 int
  388 devfs_allocv(struct devfs_dirent *de, struct mount *mp, int lockmode,
  389     struct vnode **vpp)
  390 {
  391         int error;
  392         struct vnode *vp;
  393         struct cdev *dev;
  394         struct devfs_mount *dmp;
  395         struct cdevsw *dsw;
  396 
  397         dmp = VFSTODEVFS(mp);
  398         if (de->de_flags & DE_DOOMED) {
  399                 sx_xunlock(&dmp->dm_lock);
  400                 return (ENOENT);
  401         }
  402 loop:
  403         DEVFS_DE_HOLD(de);
  404         DEVFS_DMP_HOLD(dmp);
  405         mtx_lock(&devfs_de_interlock);
  406         vp = de->de_vnode;
  407         if (vp != NULL) {
  408                 VI_LOCK(vp);
  409                 mtx_unlock(&devfs_de_interlock);
  410                 sx_xunlock(&dmp->dm_lock);
  411                 vget(vp, lockmode | LK_INTERLOCK | LK_RETRY, curthread);
  412                 sx_xlock(&dmp->dm_lock);
  413                 if (devfs_allocv_drop_refs(0, dmp, de)) {
  414                         vput(vp);
  415                         return (ENOENT);
  416                 }
  417                 else if ((vp->v_iflag & VI_DOOMED) != 0) {
  418                         mtx_lock(&devfs_de_interlock);
  419                         if (de->de_vnode == vp) {
  420                                 de->de_vnode = NULL;
  421                                 vp->v_data = NULL;
  422                         }
  423                         mtx_unlock(&devfs_de_interlock);
  424                         vput(vp);
  425                         goto loop;
  426                 }
  427                 sx_xunlock(&dmp->dm_lock);
  428                 *vpp = vp;
  429                 return (0);
  430         }
  431         mtx_unlock(&devfs_de_interlock);
  432         if (de->de_dirent->d_type == DT_CHR) {
  433                 if (!(de->de_cdp->cdp_flags & CDP_ACTIVE)) {
  434                         devfs_allocv_drop_refs(1, dmp, de);
  435                         return (ENOENT);
  436                 }
  437                 dev = &de->de_cdp->cdp_c;
  438         } else {
  439                 dev = NULL;
  440         }
  441         error = getnewvnode("devfs", mp, &devfs_vnodeops, &vp);
  442         if (error != 0) {
  443                 devfs_allocv_drop_refs(1, dmp, de);
  444                 printf("devfs_allocv: failed to allocate new vnode\n");
  445                 return (error);
  446         }
  447 
  448         if (de->de_dirent->d_type == DT_CHR) {
  449                 vp->v_type = VCHR;
  450                 VI_LOCK(vp);
  451                 dev_lock();
  452                 dev_refl(dev);
  453                 /* XXX: v_rdev should be protect by vnode lock */
  454                 vp->v_rdev = dev;
  455                 KASSERT(vp->v_usecount == 1,
  456                     ("%s %d (%d)\n", __func__, __LINE__, vp->v_usecount));
  457                 dev->si_usecount += vp->v_usecount;
  458                 /* Special casing of ttys for deadfs.  Probably redundant. */
  459                 dsw = dev->si_devsw;
  460                 if (dsw != NULL && (dsw->d_flags & D_TTY) != 0)
  461                         vp->v_vflag |= VV_ISTTY;
  462                 dev_unlock();
  463                 VI_UNLOCK(vp);
  464                 if ((dev->si_flags & SI_ETERNAL) != 0)
  465                         vp->v_vflag |= VV_ETERNALDEV;
  466                 vp->v_op = &devfs_specops;
  467         } else if (de->de_dirent->d_type == DT_DIR) {
  468                 vp->v_type = VDIR;
  469         } else if (de->de_dirent->d_type == DT_LNK) {
  470                 vp->v_type = VLNK;
  471         } else {
  472                 vp->v_type = VBAD;
  473         }
  474         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOWITNESS);
  475         VN_LOCK_ASHARE(vp);
  476         mtx_lock(&devfs_de_interlock);
  477         vp->v_data = de;
  478         de->de_vnode = vp;
  479         mtx_unlock(&devfs_de_interlock);
  480         error = insmntque1(vp, mp, devfs_insmntque_dtr, de);
  481         if (error != 0) {
  482                 (void) devfs_allocv_drop_refs(1, dmp, de);
  483                 return (error);
  484         }
  485         if (devfs_allocv_drop_refs(0, dmp, de)) {
  486                 vput(vp);
  487                 return (ENOENT);
  488         }
  489 #ifdef MAC
  490         mac_devfs_vnode_associate(mp, de, vp);
  491 #endif
  492         sx_xunlock(&dmp->dm_lock);
  493         *vpp = vp;
  494         return (0);
  495 }
  496 
  497 static int
  498 devfs_access(struct vop_access_args *ap)
  499 {
  500         struct vnode *vp = ap->a_vp;
  501         struct devfs_dirent *de;
  502         int error;
  503 
  504         de = vp->v_data;
  505         if (vp->v_type == VDIR)
  506                 de = de->de_dir;
  507 
  508         error = vaccess(vp->v_type, de->de_mode, de->de_uid, de->de_gid,
  509             ap->a_accmode, ap->a_cred, NULL);
  510         if (error == 0)
  511                 return (0);
  512         if (error != EACCES)
  513                 return (error);
  514         /* We do, however, allow access to the controlling terminal */
  515         if (!(ap->a_td->td_proc->p_flag & P_CONTROLT))
  516                 return (error);
  517         if (ap->a_td->td_proc->p_session->s_ttydp == de->de_cdp)
  518                 return (0);
  519         return (error);
  520 }
  521 
  522 /* ARGSUSED */
  523 static int
  524 devfs_close(struct vop_close_args *ap)
  525 {
  526         struct vnode *vp = ap->a_vp, *oldvp;
  527         struct thread *td = ap->a_td;
  528         struct cdev *dev = vp->v_rdev;
  529         struct cdevsw *dsw;
  530         int vp_locked, error, ref;
  531 
  532         /*
  533          * XXX: Don't call d_close() if we were called because of
  534          * XXX: insmntque1() failure.
  535          */
  536         if (vp->v_data == NULL)
  537                 return (0);
  538 
  539         /*
  540          * Hack: a tty device that is a controlling terminal
  541          * has a reference from the session structure.
  542          * We cannot easily tell that a character device is
  543          * a controlling terminal, unless it is the closing
  544          * process' controlling terminal.  In that case,
  545          * if the reference count is 2 (this last descriptor
  546          * plus the session), release the reference from the session.
  547          */
  548         oldvp = NULL;
  549         sx_xlock(&proctree_lock);
  550         if (td && vp == td->td_proc->p_session->s_ttyvp) {
  551                 SESS_LOCK(td->td_proc->p_session);
  552                 VI_LOCK(vp);
  553                 if (count_dev(dev) == 2 && (vp->v_iflag & VI_DOOMED) == 0) {
  554                         td->td_proc->p_session->s_ttyvp = NULL;
  555                         td->td_proc->p_session->s_ttydp = NULL;
  556                         oldvp = vp;
  557                 }
  558                 VI_UNLOCK(vp);
  559                 SESS_UNLOCK(td->td_proc->p_session);
  560         }
  561         sx_xunlock(&proctree_lock);
  562         if (oldvp != NULL)
  563                 vrele(oldvp);
  564         /*
  565          * We do not want to really close the device if it
  566          * is still in use unless we are trying to close it
  567          * forcibly. Since every use (buffer, vnode, swap, cmap)
  568          * holds a reference to the vnode, and because we mark
  569          * any other vnodes that alias this device, when the
  570          * sum of the reference counts on all the aliased
  571          * vnodes descends to one, we are on last close.
  572          */
  573         dsw = dev_refthread(dev, &ref);
  574         if (dsw == NULL)
  575                 return (ENXIO);
  576         VI_LOCK(vp);
  577         if (vp->v_iflag & VI_DOOMED) {
  578                 /* Forced close. */
  579         } else if (dsw->d_flags & D_TRACKCLOSE) {
  580                 /* Keep device updated on status. */
  581         } else if (count_dev(dev) > 1) {
  582                 VI_UNLOCK(vp);
  583                 dev_relthread(dev, ref);
  584                 return (0);
  585         }
  586         vholdl(vp);
  587         VI_UNLOCK(vp);
  588         vp_locked = VOP_ISLOCKED(vp);
  589         VOP_UNLOCK(vp, 0);
  590         KASSERT(dev->si_refcount > 0,
  591             ("devfs_close() on un-referenced struct cdev *(%s)", devtoname(dev)));
  592         error = dsw->d_close(dev, ap->a_fflag, S_IFCHR, td);
  593         dev_relthread(dev, ref);
  594         vn_lock(vp, vp_locked | LK_RETRY);
  595         vdrop(vp);
  596         return (error);
  597 }
  598 
  599 static int
  600 devfs_close_f(struct file *fp, struct thread *td)
  601 {
  602         int error;
  603         struct file *fpop;
  604 
  605         /*
  606          * NB: td may be NULL if this descriptor is closed due to
  607          * garbage collection from a closed UNIX domain socket.
  608          */
  609         fpop = curthread->td_fpop;
  610         curthread->td_fpop = fp;
  611         error = vnops.fo_close(fp, td);
  612         curthread->td_fpop = fpop;
  613 
  614         /*
  615          * The f_cdevpriv cannot be assigned non-NULL value while we
  616          * are destroying the file.
  617          */
  618         if (fp->f_cdevpriv != NULL)
  619                 devfs_fpdrop(fp);
  620         return (error);
  621 }
  622 
  623 static int
  624 devfs_fsync(struct vop_fsync_args *ap)
  625 {
  626         int error;
  627         struct bufobj *bo;
  628         struct devfs_dirent *de;
  629 
  630         if (!vn_isdisk(ap->a_vp, &error)) {
  631                 bo = &ap->a_vp->v_bufobj;
  632                 de = ap->a_vp->v_data;
  633                 if (error == ENXIO && bo->bo_dirty.bv_cnt > 0) {
  634                         printf("Device %s went missing before all of the data "
  635                             "could be written to it; expect data loss.\n",
  636                             de->de_dirent->d_name);
  637 
  638                         error = vop_stdfsync(ap);
  639                         if (bo->bo_dirty.bv_cnt != 0 || error != 0)
  640                                 panic("devfs_fsync: vop_stdfsync failed.");
  641                 }
  642 
  643                 return (0);
  644         }
  645 
  646         return (vop_stdfsync(ap));
  647 }
  648 
  649 static int
  650 devfs_getattr(struct vop_getattr_args *ap)
  651 {
  652         struct vnode *vp = ap->a_vp;
  653         struct vattr *vap = ap->a_vap;
  654         int error;
  655         struct devfs_dirent *de;
  656         struct devfs_mount *dmp;
  657         struct cdev *dev;
  658 
  659         error = devfs_populate_vp(vp);
  660         if (error != 0)
  661                 return (error);
  662 
  663         dmp = VFSTODEVFS(vp->v_mount);
  664         sx_xunlock(&dmp->dm_lock);
  665 
  666         de = vp->v_data;
  667         KASSERT(de != NULL, ("Null dirent in devfs_getattr vp=%p", vp));
  668         if (vp->v_type == VDIR) {
  669                 de = de->de_dir;
  670                 KASSERT(de != NULL,
  671                     ("Null dir dirent in devfs_getattr vp=%p", vp));
  672         }
  673         vap->va_uid = de->de_uid;
  674         vap->va_gid = de->de_gid;
  675         vap->va_mode = de->de_mode;
  676         if (vp->v_type == VLNK)
  677                 vap->va_size = strlen(de->de_symlink);
  678         else if (vp->v_type == VDIR)
  679                 vap->va_size = vap->va_bytes = DEV_BSIZE;
  680         else
  681                 vap->va_size = 0;
  682         if (vp->v_type != VDIR)
  683                 vap->va_bytes = 0;
  684         vap->va_blocksize = DEV_BSIZE;
  685         vap->va_type = vp->v_type;
  686 
  687 #define fix(aa)                                                 \
  688         do {                                                    \
  689                 if ((aa).tv_sec <= 3600) {                      \
  690                         (aa).tv_sec = boottime.tv_sec;          \
  691                         (aa).tv_nsec = boottime.tv_usec * 1000; \
  692                 }                                               \
  693         } while (0)
  694 
  695         if (vp->v_type != VCHR)  {
  696                 fix(de->de_atime);
  697                 vap->va_atime = de->de_atime;
  698                 fix(de->de_mtime);
  699                 vap->va_mtime = de->de_mtime;
  700                 fix(de->de_ctime);
  701                 vap->va_ctime = de->de_ctime;
  702         } else {
  703                 dev = vp->v_rdev;
  704                 fix(dev->si_atime);
  705                 vap->va_atime = dev->si_atime;
  706                 fix(dev->si_mtime);
  707                 vap->va_mtime = dev->si_mtime;
  708                 fix(dev->si_ctime);
  709                 vap->va_ctime = dev->si_ctime;
  710 
  711                 vap->va_rdev = cdev2priv(dev)->cdp_inode;
  712         }
  713         vap->va_gen = 0;
  714         vap->va_flags = 0;
  715         vap->va_filerev = 0;
  716         vap->va_nlink = de->de_links;
  717         vap->va_fileid = de->de_inode;
  718 
  719         return (error);
  720 }
  721 
  722 /* ARGSUSED */
  723 static int
  724 devfs_ioctl_f(struct file *fp, u_long com, void *data, struct ucred *cred, struct thread *td)
  725 {
  726         struct cdev *dev;
  727         struct cdevsw *dsw;
  728         struct vnode *vp;
  729         struct vnode *vpold;
  730         int error, i, ref;
  731         const char *p;
  732         struct fiodgname_arg *fgn;
  733         struct file *fpop;
  734 
  735         fpop = td->td_fpop;
  736         error = devfs_fp_check(fp, &dev, &dsw, &ref);
  737         if (error)
  738                 return (error);
  739 
  740         if (com == FIODTYPE) {
  741                 *(int *)data = dsw->d_flags & D_TYPEMASK;
  742                 td->td_fpop = fpop;
  743                 dev_relthread(dev, ref);
  744                 return (0);
  745         } else if (com == FIODGNAME) {
  746                 fgn = data;
  747                 p = devtoname(dev);
  748                 i = strlen(p) + 1;
  749                 if (i > fgn->len)
  750                         error = EINVAL;
  751                 else
  752                         error = copyout(p, fgn->buf, i);
  753                 td->td_fpop = fpop;
  754                 dev_relthread(dev, ref);
  755                 return (error);
  756         }
  757         error = dsw->d_ioctl(dev, com, data, fp->f_flag, td);
  758         td->td_fpop = NULL;
  759         dev_relthread(dev, ref);
  760         if (error == ENOIOCTL)
  761                 error = ENOTTY;
  762         if (error == 0 && com == TIOCSCTTY) {
  763                 vp = fp->f_vnode;
  764 
  765                 /* Do nothing if reassigning same control tty */
  766                 sx_slock(&proctree_lock);
  767                 if (td->td_proc->p_session->s_ttyvp == vp) {
  768                         sx_sunlock(&proctree_lock);
  769                         return (0);
  770                 }
  771 
  772                 vpold = td->td_proc->p_session->s_ttyvp;
  773                 VREF(vp);
  774                 SESS_LOCK(td->td_proc->p_session);
  775                 td->td_proc->p_session->s_ttyvp = vp;
  776                 td->td_proc->p_session->s_ttydp = cdev2priv(dev);
  777                 SESS_UNLOCK(td->td_proc->p_session);
  778 
  779                 sx_sunlock(&proctree_lock);
  780 
  781                 /* Get rid of reference to old control tty */
  782                 if (vpold)
  783                         vrele(vpold);
  784         }
  785         return (error);
  786 }
  787 
  788 /* ARGSUSED */
  789 static int
  790 devfs_kqfilter_f(struct file *fp, struct knote *kn)
  791 {
  792         struct cdev *dev;
  793         struct cdevsw *dsw;
  794         int error, ref;
  795         struct file *fpop;
  796         struct thread *td;
  797 
  798         td = curthread;
  799         fpop = td->td_fpop;
  800         error = devfs_fp_check(fp, &dev, &dsw, &ref);
  801         if (error)
  802                 return (error);
  803         error = dsw->d_kqfilter(dev, kn);
  804         td->td_fpop = fpop;
  805         dev_relthread(dev, ref);
  806         return (error);
  807 }
  808 
  809 static inline int
  810 devfs_prison_check(struct devfs_dirent *de, struct thread *td)
  811 {
  812         struct cdev_priv *cdp;
  813         struct ucred *dcr;
  814         int error;
  815 
  816         cdp = de->de_cdp;
  817         if (cdp == NULL)
  818                 return (0);
  819         dcr = cdp->cdp_c.si_cred;
  820         if (dcr == NULL)
  821                 return (0);
  822 
  823         error = prison_check(td->td_ucred, dcr);
  824         if (error == 0)
  825                 return (0);
  826         /* We do, however, allow access to the controlling terminal */
  827         if (!(td->td_proc->p_flag & P_CONTROLT))
  828                 return (error);
  829         if (td->td_proc->p_session->s_ttydp == cdp)
  830                 return (0);
  831         return (error);
  832 }
  833 
  834 static int
  835 devfs_lookupx(struct vop_lookup_args *ap, int *dm_unlock)
  836 {
  837         struct componentname *cnp;
  838         struct vnode *dvp, **vpp;
  839         struct thread *td;
  840         struct devfs_dirent *de, *dd;
  841         struct devfs_dirent **dde;
  842         struct devfs_mount *dmp;
  843         struct cdev *cdev;
  844         int error, flags, nameiop, dvplocked;
  845         char specname[SPECNAMELEN + 1], *pname;
  846 
  847         cnp = ap->a_cnp;
  848         vpp = ap->a_vpp;
  849         dvp = ap->a_dvp;
  850         pname = cnp->cn_nameptr;
  851         td = cnp->cn_thread;
  852         flags = cnp->cn_flags;
  853         nameiop = cnp->cn_nameiop;
  854         dmp = VFSTODEVFS(dvp->v_mount);
  855         dd = dvp->v_data;
  856         *vpp = NULLVP;
  857 
  858         if ((flags & ISLASTCN) && nameiop == RENAME)
  859                 return (EOPNOTSUPP);
  860 
  861         if (dvp->v_type != VDIR)
  862                 return (ENOTDIR);
  863 
  864         if ((flags & ISDOTDOT) && (dvp->v_vflag & VV_ROOT))
  865                 return (EIO);
  866 
  867         error = VOP_ACCESS(dvp, VEXEC, cnp->cn_cred, td);
  868         if (error)
  869                 return (error);
  870 
  871         if (cnp->cn_namelen == 1 && *pname == '.') {
  872                 if ((flags & ISLASTCN) && nameiop != LOOKUP)
  873                         return (EINVAL);
  874                 *vpp = dvp;
  875                 VREF(dvp);
  876                 return (0);
  877         }
  878 
  879         if (flags & ISDOTDOT) {
  880                 if ((flags & ISLASTCN) && nameiop != LOOKUP)
  881                         return (EINVAL);
  882                 de = devfs_parent_dirent(dd);
  883                 if (de == NULL)
  884                         return (ENOENT);
  885                 dvplocked = VOP_ISLOCKED(dvp);
  886                 VOP_UNLOCK(dvp, 0);
  887                 error = devfs_allocv(de, dvp->v_mount,
  888                     cnp->cn_lkflags & LK_TYPE_MASK, vpp);
  889                 *dm_unlock = 0;
  890                 vn_lock(dvp, dvplocked | LK_RETRY);
  891                 return (error);
  892         }
  893 
  894         dd = dvp->v_data;
  895         de = devfs_find(dd, cnp->cn_nameptr, cnp->cn_namelen, 0);
  896         while (de == NULL) {    /* While(...) so we can use break */
  897 
  898                 if (nameiop == DELETE)
  899                         return (ENOENT);
  900 
  901                 /*
  902                  * OK, we didn't have an entry for the name we were asked for
  903                  * so we try to see if anybody can create it on demand.
  904                  */
  905                 pname = devfs_fqpn(specname, dmp, dd, cnp);
  906                 if (pname == NULL)
  907                         break;
  908 
  909                 cdev = NULL;
  910                 DEVFS_DMP_HOLD(dmp);
  911                 sx_xunlock(&dmp->dm_lock);
  912                 sx_slock(&clone_drain_lock);
  913                 EVENTHANDLER_INVOKE(dev_clone,
  914                     td->td_ucred, pname, strlen(pname), &cdev);
  915                 sx_sunlock(&clone_drain_lock);
  916 
  917                 if (cdev == NULL)
  918                         sx_xlock(&dmp->dm_lock);
  919                 else if (devfs_populate_vp(dvp) != 0) {
  920                         *dm_unlock = 0;
  921                         sx_xlock(&dmp->dm_lock);
  922                         if (DEVFS_DMP_DROP(dmp)) {
  923                                 sx_xunlock(&dmp->dm_lock);
  924                                 devfs_unmount_final(dmp);
  925                         } else
  926                                 sx_xunlock(&dmp->dm_lock);
  927                         dev_rel(cdev);
  928                         return (ENOENT);
  929                 }
  930                 if (DEVFS_DMP_DROP(dmp)) {
  931                         *dm_unlock = 0;
  932                         sx_xunlock(&dmp->dm_lock);
  933                         devfs_unmount_final(dmp);
  934                         if (cdev != NULL)
  935                                 dev_rel(cdev);
  936                         return (ENOENT);
  937                 }
  938 
  939                 if (cdev == NULL)
  940                         break;
  941 
  942                 dev_lock();
  943                 dde = &cdev2priv(cdev)->cdp_dirents[dmp->dm_idx];
  944                 if (dde != NULL && *dde != NULL)
  945                         de = *dde;
  946                 dev_unlock();
  947                 dev_rel(cdev);
  948                 break;
  949         }
  950 
  951         if (de == NULL || de->de_flags & DE_WHITEOUT) {
  952                 if ((nameiop == CREATE || nameiop == RENAME) &&
  953                     (flags & (LOCKPARENT | WANTPARENT)) && (flags & ISLASTCN)) {
  954                         cnp->cn_flags |= SAVENAME;
  955                         return (EJUSTRETURN);
  956                 }
  957                 return (ENOENT);
  958         }
  959 
  960         if (devfs_prison_check(de, td))
  961                 return (ENOENT);
  962 
  963         if ((cnp->cn_nameiop == DELETE) && (flags & ISLASTCN)) {
  964                 error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred, td);
  965                 if (error)
  966                         return (error);
  967                 if (*vpp == dvp) {
  968                         VREF(dvp);
  969                         *vpp = dvp;
  970                         return (0);
  971                 }
  972         }
  973         error = devfs_allocv(de, dvp->v_mount, cnp->cn_lkflags & LK_TYPE_MASK,
  974             vpp);
  975         *dm_unlock = 0;
  976         return (error);
  977 }
  978 
  979 static int
  980 devfs_lookup(struct vop_lookup_args *ap)
  981 {
  982         int j;
  983         struct devfs_mount *dmp;
  984         int dm_unlock;
  985 
  986         if (devfs_populate_vp(ap->a_dvp) != 0)
  987                 return (ENOTDIR);
  988 
  989         dmp = VFSTODEVFS(ap->a_dvp->v_mount);
  990         dm_unlock = 1;
  991         j = devfs_lookupx(ap, &dm_unlock);
  992         if (dm_unlock == 1)
  993                 sx_xunlock(&dmp->dm_lock);
  994         return (j);
  995 }
  996 
  997 static int
  998 devfs_mknod(struct vop_mknod_args *ap)
  999 {
 1000         struct componentname *cnp;
 1001         struct vnode *dvp, **vpp;
 1002         struct devfs_dirent *dd, *de;
 1003         struct devfs_mount *dmp;
 1004         int error;
 1005 
 1006         /*
 1007          * The only type of node we should be creating here is a
 1008          * character device, for anything else return EOPNOTSUPP.
 1009          */
 1010         if (ap->a_vap->va_type != VCHR)
 1011                 return (EOPNOTSUPP);
 1012         dvp = ap->a_dvp;
 1013         dmp = VFSTODEVFS(dvp->v_mount);
 1014 
 1015         cnp = ap->a_cnp;
 1016         vpp = ap->a_vpp;
 1017         dd = dvp->v_data;
 1018 
 1019         error = ENOENT;
 1020         sx_xlock(&dmp->dm_lock);
 1021         TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
 1022                 if (cnp->cn_namelen != de->de_dirent->d_namlen)
 1023                         continue;
 1024                 if (bcmp(cnp->cn_nameptr, de->de_dirent->d_name,
 1025                     de->de_dirent->d_namlen) != 0)
 1026                         continue;
 1027                 if (de->de_flags & DE_WHITEOUT)
 1028                         break;
 1029                 goto notfound;
 1030         }
 1031         if (de == NULL)
 1032                 goto notfound;
 1033         de->de_flags &= ~DE_WHITEOUT;
 1034         error = devfs_allocv(de, dvp->v_mount, LK_EXCLUSIVE, vpp);
 1035         return (error);
 1036 notfound:
 1037         sx_xunlock(&dmp->dm_lock);
 1038         return (error);
 1039 }
 1040 
 1041 /* ARGSUSED */
 1042 static int
 1043 devfs_open(struct vop_open_args *ap)
 1044 {
 1045         struct thread *td = ap->a_td;
 1046         struct vnode *vp = ap->a_vp;
 1047         struct cdev *dev = vp->v_rdev;
 1048         struct file *fp = ap->a_fp;
 1049         int error, ref, vlocked;
 1050         struct cdevsw *dsw;
 1051         struct file *fpop;
 1052         struct mtx *mtxp;
 1053 
 1054         if (vp->v_type == VBLK)
 1055                 return (ENXIO);
 1056 
 1057         if (dev == NULL)
 1058                 return (ENXIO);
 1059 
 1060         /* Make this field valid before any I/O in d_open. */
 1061         if (dev->si_iosize_max == 0)
 1062                 dev->si_iosize_max = DFLTPHYS;
 1063 
 1064         dsw = dev_refthread(dev, &ref);
 1065         if (dsw == NULL)
 1066                 return (ENXIO);
 1067         if (fp == NULL && dsw->d_fdopen != NULL) {
 1068                 dev_relthread(dev, ref);
 1069                 return (ENXIO);
 1070         }
 1071 
 1072         vlocked = VOP_ISLOCKED(vp);
 1073         VOP_UNLOCK(vp, 0);
 1074 
 1075         fpop = td->td_fpop;
 1076         td->td_fpop = fp;
 1077         if (fp != NULL) {
 1078                 fp->f_data = dev;
 1079                 fp->f_vnode = vp;
 1080         }
 1081         if (dsw->d_fdopen != NULL)
 1082                 error = dsw->d_fdopen(dev, ap->a_mode, td, fp);
 1083         else
 1084                 error = dsw->d_open(dev, ap->a_mode, S_IFCHR, td);
 1085         /* cleanup any cdevpriv upon error */
 1086         if (error != 0)
 1087                 devfs_clear_cdevpriv();
 1088         td->td_fpop = fpop;
 1089 
 1090         vn_lock(vp, vlocked | LK_RETRY);
 1091         dev_relthread(dev, ref);
 1092         if (error != 0) {
 1093                 if (error == ERESTART)
 1094                         error = EINTR;
 1095                 return (error);
 1096         }
 1097 
 1098 #if 0   /* /dev/console */
 1099         KASSERT(fp != NULL, ("Could not vnode bypass device on NULL fp"));
 1100 #else
 1101         if (fp == NULL)
 1102                 return (error);
 1103 #endif
 1104         if (fp->f_ops == &badfileops)
 1105                 finit(fp, fp->f_flag, DTYPE_VNODE, dev, &devfs_ops_f);
 1106         mtxp = mtx_pool_find(mtxpool_sleep, fp);
 1107 
 1108         /*
 1109          * Hint to the dofilewrite() to not force the buffer draining
 1110          * on the writer to the file.  Most likely, the write would
 1111          * not need normal buffers.
 1112          */
 1113         mtx_lock(mtxp);
 1114         fp->f_vnread_flags |= FDEVFS_VNODE;
 1115         mtx_unlock(mtxp);
 1116         return (error);
 1117 }
 1118 
 1119 static int
 1120 devfs_pathconf(struct vop_pathconf_args *ap)
 1121 {
 1122 
 1123         switch (ap->a_name) {
 1124         case _PC_MAC_PRESENT:
 1125 #ifdef MAC
 1126                 /*
 1127                  * If MAC is enabled, devfs automatically supports
 1128                  * trivial non-persistant label storage.
 1129                  */
 1130                 *ap->a_retval = 1;
 1131 #else
 1132                 *ap->a_retval = 0;
 1133 #endif
 1134                 return (0);
 1135         default:
 1136                 return (vop_stdpathconf(ap));
 1137         }
 1138         /* NOTREACHED */
 1139 }
 1140 
 1141 /* ARGSUSED */
 1142 static int
 1143 devfs_poll_f(struct file *fp, int events, struct ucred *cred, struct thread *td)
 1144 {
 1145         struct cdev *dev;
 1146         struct cdevsw *dsw;
 1147         int error, ref;
 1148         struct file *fpop;
 1149 
 1150         fpop = td->td_fpop;
 1151         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1152         if (error)
 1153                 return (poll_no_poll(events));
 1154         error = dsw->d_poll(dev, events, td);
 1155         td->td_fpop = fpop;
 1156         dev_relthread(dev, ref);
 1157         return(error);
 1158 }
 1159 
 1160 /*
 1161  * Print out the contents of a special device vnode.
 1162  */
 1163 static int
 1164 devfs_print(struct vop_print_args *ap)
 1165 {
 1166 
 1167         printf("\tdev %s\n", devtoname(ap->a_vp->v_rdev));
 1168         return (0);
 1169 }
 1170 
 1171 static int
 1172 devfs_read_f(struct file *fp, struct uio *uio, struct ucred *cred,
 1173     int flags, struct thread *td)
 1174 {
 1175         struct cdev *dev;
 1176         int ioflag, error, ref;
 1177         ssize_t resid;
 1178         struct cdevsw *dsw;
 1179         struct file *fpop;
 1180 
 1181         if (uio->uio_resid > DEVFS_IOSIZE_MAX)
 1182                 return (EINVAL);
 1183         fpop = td->td_fpop;
 1184         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1185         if (error)
 1186                 return (error);
 1187         resid = uio->uio_resid;
 1188         ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT);
 1189         if (ioflag & O_DIRECT)
 1190                 ioflag |= IO_DIRECT;
 1191 
 1192         foffset_lock_uio(fp, uio, flags | FOF_NOLOCK);
 1193         error = dsw->d_read(dev, uio, ioflag);
 1194         if (uio->uio_resid != resid || (error == 0 && resid != 0))
 1195                 vfs_timestamp(&dev->si_atime);
 1196         td->td_fpop = fpop;
 1197         dev_relthread(dev, ref);
 1198 
 1199         foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF);
 1200         return (error);
 1201 }
 1202 
 1203 static int
 1204 devfs_readdir(struct vop_readdir_args *ap)
 1205 {
 1206         int error;
 1207         struct uio *uio;
 1208         struct dirent *dp;
 1209         struct devfs_dirent *dd;
 1210         struct devfs_dirent *de;
 1211         struct devfs_mount *dmp;
 1212         off_t off;
 1213         int *tmp_ncookies = NULL;
 1214 
 1215         if (ap->a_vp->v_type != VDIR)
 1216                 return (ENOTDIR);
 1217 
 1218         uio = ap->a_uio;
 1219         if (uio->uio_offset < 0)
 1220                 return (EINVAL);
 1221 
 1222         /*
 1223          * XXX: This is a temporary hack to get around this filesystem not
 1224          * supporting cookies. We store the location of the ncookies pointer
 1225          * in a temporary variable before calling vfs_subr.c:vfs_read_dirent()
 1226          * and set the number of cookies to 0. We then set the pointer to
 1227          * NULL so that vfs_read_dirent doesn't try to call realloc() on 
 1228          * ap->a_cookies. Later in this function, we restore the ap->a_ncookies
 1229          * pointer to its original location before returning to the caller.
 1230          */
 1231         if (ap->a_ncookies != NULL) {
 1232                 tmp_ncookies = ap->a_ncookies;
 1233                 *ap->a_ncookies = 0;
 1234                 ap->a_ncookies = NULL;
 1235         }
 1236 
 1237         dmp = VFSTODEVFS(ap->a_vp->v_mount);
 1238         if (devfs_populate_vp(ap->a_vp) != 0) {
 1239                 if (tmp_ncookies != NULL)
 1240                         ap->a_ncookies = tmp_ncookies;
 1241                 return (EIO);
 1242         }
 1243         error = 0;
 1244         de = ap->a_vp->v_data;
 1245         off = 0;
 1246         TAILQ_FOREACH(dd, &de->de_dlist, de_list) {
 1247                 KASSERT(dd->de_cdp != (void *)0xdeadc0de, ("%s %d\n", __func__, __LINE__));
 1248                 if (dd->de_flags & (DE_COVERED | DE_WHITEOUT))
 1249                         continue;
 1250                 if (devfs_prison_check(dd, uio->uio_td))
 1251                         continue;
 1252                 if (dd->de_dirent->d_type == DT_DIR)
 1253                         de = dd->de_dir;
 1254                 else
 1255                         de = dd;
 1256                 dp = dd->de_dirent;
 1257                 if (dp->d_reclen > uio->uio_resid)
 1258                         break;
 1259                 dp->d_fileno = de->de_inode;
 1260                 if (off >= uio->uio_offset) {
 1261                         error = vfs_read_dirent(ap, dp, off);
 1262                         if (error)
 1263                                 break;
 1264                 }
 1265                 off += dp->d_reclen;
 1266         }
 1267         sx_xunlock(&dmp->dm_lock);
 1268         uio->uio_offset = off;
 1269 
 1270         /*
 1271          * Restore ap->a_ncookies if it wasn't originally NULL in the first
 1272          * place.
 1273          */
 1274         if (tmp_ncookies != NULL)
 1275                 ap->a_ncookies = tmp_ncookies;
 1276 
 1277         return (error);
 1278 }
 1279 
 1280 static int
 1281 devfs_readlink(struct vop_readlink_args *ap)
 1282 {
 1283         struct devfs_dirent *de;
 1284 
 1285         de = ap->a_vp->v_data;
 1286         return (uiomove(de->de_symlink, strlen(de->de_symlink), ap->a_uio));
 1287 }
 1288 
 1289 static int
 1290 devfs_reclaim(struct vop_reclaim_args *ap)
 1291 {
 1292         struct vnode *vp = ap->a_vp;
 1293         struct devfs_dirent *de;
 1294         struct cdev *dev;
 1295 
 1296         mtx_lock(&devfs_de_interlock);
 1297         de = vp->v_data;
 1298         if (de != NULL) {
 1299                 de->de_vnode = NULL;
 1300                 vp->v_data = NULL;
 1301         }
 1302         mtx_unlock(&devfs_de_interlock);
 1303 
 1304         vnode_destroy_vobject(vp);
 1305 
 1306         VI_LOCK(vp);
 1307         dev_lock();
 1308         dev = vp->v_rdev;
 1309         vp->v_rdev = NULL;
 1310 
 1311         if (dev == NULL) {
 1312                 dev_unlock();
 1313                 VI_UNLOCK(vp);
 1314                 return (0);
 1315         }
 1316 
 1317         dev->si_usecount -= vp->v_usecount;
 1318         dev_unlock();
 1319         VI_UNLOCK(vp);
 1320         dev_rel(dev);
 1321         return (0);
 1322 }
 1323 
 1324 static int
 1325 devfs_remove(struct vop_remove_args *ap)
 1326 {
 1327         struct vnode *dvp = ap->a_dvp;
 1328         struct vnode *vp = ap->a_vp;
 1329         struct devfs_dirent *dd;
 1330         struct devfs_dirent *de, *de_covered;
 1331         struct devfs_mount *dmp = VFSTODEVFS(vp->v_mount);
 1332 
 1333         ASSERT_VOP_ELOCKED(dvp, "devfs_remove");
 1334         ASSERT_VOP_ELOCKED(vp, "devfs_remove");
 1335 
 1336         sx_xlock(&dmp->dm_lock);
 1337         dd = ap->a_dvp->v_data;
 1338         de = vp->v_data;
 1339         if (de->de_cdp == NULL) {
 1340                 TAILQ_REMOVE(&dd->de_dlist, de, de_list);
 1341                 if (de->de_dirent->d_type == DT_LNK) {
 1342                         de_covered = devfs_find(dd, de->de_dirent->d_name,
 1343                             de->de_dirent->d_namlen, 0);
 1344                         if (de_covered != NULL)
 1345                                 de_covered->de_flags &= ~DE_COVERED;
 1346                 }
 1347                 /* We need to unlock dvp because devfs_delete() may lock it. */
 1348                 VOP_UNLOCK(vp, 0);
 1349                 if (dvp != vp)
 1350                         VOP_UNLOCK(dvp, 0);
 1351                 devfs_delete(dmp, de, 0);
 1352                 sx_xunlock(&dmp->dm_lock);
 1353                 if (dvp != vp)
 1354                         vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
 1355                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1356         } else {
 1357                 de->de_flags |= DE_WHITEOUT;
 1358                 sx_xunlock(&dmp->dm_lock);
 1359         }
 1360         return (0);
 1361 }
 1362 
 1363 /*
 1364  * Revoke is called on a tty when a terminal session ends.  The vnode
 1365  * is orphaned by setting v_op to deadfs so we need to let go of it
 1366  * as well so that we create a new one next time around.
 1367  *
 1368  */
 1369 static int
 1370 devfs_revoke(struct vop_revoke_args *ap)
 1371 {
 1372         struct vnode *vp = ap->a_vp, *vp2;
 1373         struct cdev *dev;
 1374         struct cdev_priv *cdp;
 1375         struct devfs_dirent *de;
 1376         int i;
 1377 
 1378         KASSERT((ap->a_flags & REVOKEALL) != 0, ("devfs_revoke !REVOKEALL"));
 1379 
 1380         dev = vp->v_rdev;
 1381         cdp = cdev2priv(dev);
 1382  
 1383         dev_lock();
 1384         cdp->cdp_inuse++;
 1385         dev_unlock();
 1386 
 1387         vhold(vp);
 1388         vgone(vp);
 1389         vdrop(vp);
 1390 
 1391         VOP_UNLOCK(vp,0);
 1392  loop:
 1393         for (;;) {
 1394                 mtx_lock(&devfs_de_interlock);
 1395                 dev_lock();
 1396                 vp2 = NULL;
 1397                 for (i = 0; i <= cdp->cdp_maxdirent; i++) {
 1398                         de = cdp->cdp_dirents[i];
 1399                         if (de == NULL)
 1400                                 continue;
 1401 
 1402                         vp2 = de->de_vnode;
 1403                         if (vp2 != NULL) {
 1404                                 dev_unlock();
 1405                                 VI_LOCK(vp2);
 1406                                 mtx_unlock(&devfs_de_interlock);
 1407                                 if (vget(vp2, LK_EXCLUSIVE | LK_INTERLOCK,
 1408                                     curthread))
 1409                                         goto loop;
 1410                                 vhold(vp2);
 1411                                 vgone(vp2);
 1412                                 vdrop(vp2);
 1413                                 vput(vp2);
 1414                                 break;
 1415                         } 
 1416                 }
 1417                 if (vp2 != NULL) {
 1418                         continue;
 1419                 }
 1420                 dev_unlock();
 1421                 mtx_unlock(&devfs_de_interlock);
 1422                 break;
 1423         }
 1424         dev_lock();
 1425         cdp->cdp_inuse--;
 1426         if (!(cdp->cdp_flags & CDP_ACTIVE) && cdp->cdp_inuse == 0) {
 1427                 TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
 1428                 dev_unlock();
 1429                 dev_rel(&cdp->cdp_c);
 1430         } else
 1431                 dev_unlock();
 1432 
 1433         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 1434         return (0);
 1435 }
 1436 
 1437 static int
 1438 devfs_rioctl(struct vop_ioctl_args *ap)
 1439 {
 1440         struct vnode *vp;
 1441         struct devfs_mount *dmp;
 1442         int error;
 1443 
 1444         vp = ap->a_vp;
 1445         vn_lock(vp, LK_SHARED | LK_RETRY);
 1446         if (vp->v_iflag & VI_DOOMED) {
 1447                 VOP_UNLOCK(vp, 0);
 1448                 return (EBADF);
 1449         }
 1450         dmp = VFSTODEVFS(vp->v_mount);
 1451         sx_xlock(&dmp->dm_lock);
 1452         VOP_UNLOCK(vp, 0);
 1453         DEVFS_DMP_HOLD(dmp);
 1454         devfs_populate(dmp);
 1455         if (DEVFS_DMP_DROP(dmp)) {
 1456                 sx_xunlock(&dmp->dm_lock);
 1457                 devfs_unmount_final(dmp);
 1458                 return (ENOENT);
 1459         }
 1460         error = devfs_rules_ioctl(dmp, ap->a_command, ap->a_data, ap->a_td);
 1461         sx_xunlock(&dmp->dm_lock);
 1462         return (error);
 1463 }
 1464 
 1465 static int
 1466 devfs_rread(struct vop_read_args *ap)
 1467 {
 1468 
 1469         if (ap->a_vp->v_type != VDIR)
 1470                 return (EINVAL);
 1471         return (VOP_READDIR(ap->a_vp, ap->a_uio, ap->a_cred, NULL, NULL, NULL));
 1472 }
 1473 
 1474 static int
 1475 devfs_setattr(struct vop_setattr_args *ap)
 1476 {
 1477         struct devfs_dirent *de;
 1478         struct vattr *vap;
 1479         struct vnode *vp;
 1480         struct thread *td;
 1481         int c, error;
 1482         uid_t uid;
 1483         gid_t gid;
 1484 
 1485         vap = ap->a_vap;
 1486         vp = ap->a_vp;
 1487         td = curthread;
 1488         if ((vap->va_type != VNON) ||
 1489             (vap->va_nlink != VNOVAL) ||
 1490             (vap->va_fsid != VNOVAL) ||
 1491             (vap->va_fileid != VNOVAL) ||
 1492             (vap->va_blocksize != VNOVAL) ||
 1493             (vap->va_flags != VNOVAL && vap->va_flags != 0) ||
 1494             (vap->va_rdev != VNOVAL) ||
 1495             ((int)vap->va_bytes != VNOVAL) ||
 1496             (vap->va_gen != VNOVAL)) {
 1497                 return (EINVAL);
 1498         }
 1499 
 1500         de = vp->v_data;
 1501         if (vp->v_type == VDIR)
 1502                 de = de->de_dir;
 1503 
 1504         error = c = 0;
 1505         if (vap->va_uid == (uid_t)VNOVAL)
 1506                 uid = de->de_uid;
 1507         else
 1508                 uid = vap->va_uid;
 1509         if (vap->va_gid == (gid_t)VNOVAL)
 1510                 gid = de->de_gid;
 1511         else
 1512                 gid = vap->va_gid;
 1513         if (uid != de->de_uid || gid != de->de_gid) {
 1514                 if ((ap->a_cred->cr_uid != de->de_uid) || uid != de->de_uid ||
 1515                     (gid != de->de_gid && !groupmember(gid, ap->a_cred))) {
 1516                         error = priv_check(td, PRIV_VFS_CHOWN);
 1517                         if (error)
 1518                                 return (error);
 1519                 }
 1520                 de->de_uid = uid;
 1521                 de->de_gid = gid;
 1522                 c = 1;
 1523         }
 1524 
 1525         if (vap->va_mode != (mode_t)VNOVAL) {
 1526                 if (ap->a_cred->cr_uid != de->de_uid) {
 1527                         error = priv_check(td, PRIV_VFS_ADMIN);
 1528                         if (error)
 1529                                 return (error);
 1530                 }
 1531                 de->de_mode = vap->va_mode;
 1532                 c = 1;
 1533         }
 1534 
 1535         if (vap->va_atime.tv_sec != VNOVAL || vap->va_mtime.tv_sec != VNOVAL) {
 1536                 /* See the comment in ufs_vnops::ufs_setattr(). */
 1537                 if ((error = VOP_ACCESS(vp, VADMIN, ap->a_cred, td)) &&
 1538                     ((vap->va_vaflags & VA_UTIMES_NULL) == 0 ||
 1539                     (error = VOP_ACCESS(vp, VWRITE, ap->a_cred, td))))
 1540                         return (error);
 1541                 if (vap->va_atime.tv_sec != VNOVAL) {
 1542                         if (vp->v_type == VCHR)
 1543                                 vp->v_rdev->si_atime = vap->va_atime;
 1544                         else
 1545                                 de->de_atime = vap->va_atime;
 1546                 }
 1547                 if (vap->va_mtime.tv_sec != VNOVAL) {
 1548                         if (vp->v_type == VCHR)
 1549                                 vp->v_rdev->si_mtime = vap->va_mtime;
 1550                         else
 1551                                 de->de_mtime = vap->va_mtime;
 1552                 }
 1553                 c = 1;
 1554         }
 1555 
 1556         if (c) {
 1557                 if (vp->v_type == VCHR)
 1558                         vfs_timestamp(&vp->v_rdev->si_ctime);
 1559                 else
 1560                         vfs_timestamp(&de->de_mtime);
 1561         }
 1562         return (0);
 1563 }
 1564 
 1565 #ifdef MAC
 1566 static int
 1567 devfs_setlabel(struct vop_setlabel_args *ap)
 1568 {
 1569         struct vnode *vp;
 1570         struct devfs_dirent *de;
 1571 
 1572         vp = ap->a_vp;
 1573         de = vp->v_data;
 1574 
 1575         mac_vnode_relabel(ap->a_cred, vp, ap->a_label);
 1576         mac_devfs_update(vp->v_mount, de, vp);
 1577 
 1578         return (0);
 1579 }
 1580 #endif
 1581 
 1582 static int
 1583 devfs_stat_f(struct file *fp, struct stat *sb, struct ucred *cred, struct thread *td)
 1584 {
 1585 
 1586         return (vnops.fo_stat(fp, sb, cred, td));
 1587 }
 1588 
 1589 static int
 1590 devfs_symlink(struct vop_symlink_args *ap)
 1591 {
 1592         int i, error;
 1593         struct devfs_dirent *dd;
 1594         struct devfs_dirent *de, *de_covered, *de_dotdot;
 1595         struct devfs_mount *dmp;
 1596 
 1597         error = priv_check(curthread, PRIV_DEVFS_SYMLINK);
 1598         if (error)
 1599                 return(error);
 1600         dmp = VFSTODEVFS(ap->a_dvp->v_mount);
 1601         if (devfs_populate_vp(ap->a_dvp) != 0)
 1602                 return (ENOENT);
 1603 
 1604         dd = ap->a_dvp->v_data;
 1605         de = devfs_newdirent(ap->a_cnp->cn_nameptr, ap->a_cnp->cn_namelen);
 1606         de->de_flags = DE_USER;
 1607         de->de_uid = 0;
 1608         de->de_gid = 0;
 1609         de->de_mode = 0755;
 1610         de->de_inode = alloc_unr(devfs_inos);
 1611         de->de_dir = dd;
 1612         de->de_dirent->d_type = DT_LNK;
 1613         i = strlen(ap->a_target) + 1;
 1614         de->de_symlink = malloc(i, M_DEVFS, M_WAITOK);
 1615         bcopy(ap->a_target, de->de_symlink, i);
 1616 #ifdef MAC
 1617         mac_devfs_create_symlink(ap->a_cnp->cn_cred, dmp->dm_mount, dd, de);
 1618 #endif
 1619         de_covered = devfs_find(dd, de->de_dirent->d_name,
 1620             de->de_dirent->d_namlen, 0);
 1621         if (de_covered != NULL) {
 1622                 if ((de_covered->de_flags & DE_USER) != 0) {
 1623                         devfs_delete(dmp, de, DEVFS_DEL_NORECURSE);
 1624                         sx_xunlock(&dmp->dm_lock);
 1625                         return (EEXIST);
 1626                 }
 1627                 KASSERT((de_covered->de_flags & DE_COVERED) == 0,
 1628                     ("devfs_symlink: entry %p already covered", de_covered));
 1629                 de_covered->de_flags |= DE_COVERED;
 1630         }
 1631 
 1632         de_dotdot = TAILQ_FIRST(&dd->de_dlist);         /* "." */
 1633         de_dotdot = TAILQ_NEXT(de_dotdot, de_list);     /* ".." */
 1634         TAILQ_INSERT_AFTER(&dd->de_dlist, de_dotdot, de, de_list);
 1635         devfs_dir_ref_de(dmp, dd);
 1636         devfs_rules_apply(dmp, de);
 1637 
 1638         return (devfs_allocv(de, ap->a_dvp->v_mount, LK_EXCLUSIVE, ap->a_vpp));
 1639 }
 1640 
 1641 static int
 1642 devfs_truncate_f(struct file *fp, off_t length, struct ucred *cred, struct thread *td)
 1643 {
 1644 
 1645         return (vnops.fo_truncate(fp, length, cred, td));
 1646 }
 1647 
 1648 static int
 1649 devfs_write_f(struct file *fp, struct uio *uio, struct ucred *cred,
 1650     int flags, struct thread *td)
 1651 {
 1652         struct cdev *dev;
 1653         int error, ioflag, ref;
 1654         ssize_t resid;
 1655         struct cdevsw *dsw;
 1656         struct file *fpop;
 1657 
 1658         if (uio->uio_resid > DEVFS_IOSIZE_MAX)
 1659                 return (EINVAL);
 1660         fpop = td->td_fpop;
 1661         error = devfs_fp_check(fp, &dev, &dsw, &ref);
 1662         if (error)
 1663                 return (error);
 1664         KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", uio->uio_td, td));
 1665         ioflag = fp->f_flag & (O_NONBLOCK | O_DIRECT | O_FSYNC);
 1666         if (ioflag & O_DIRECT)
 1667                 ioflag |= IO_DIRECT;
 1668         foffset_lock_uio(fp, uio, flags | FOF_NOLOCK);
 1669 
 1670         resid = uio->uio_resid;
 1671 
 1672         error = dsw->d_write(dev, uio, ioflag);
 1673         if (uio->uio_resid != resid || (error == 0 && resid != 0)) {
 1674                 vfs_timestamp(&dev->si_ctime);
 1675                 dev->si_mtime = dev->si_ctime;
 1676         }
 1677         td->td_fpop = fpop;
 1678         dev_relthread(dev, ref);
 1679 
 1680         foffset_unlock_uio(fp, uio, flags | FOF_NOLOCK | FOF_NEXTOFF);
 1681         return (error);
 1682 }
 1683 
 1684 dev_t
 1685 dev2udev(struct cdev *x)
 1686 {
 1687         if (x == NULL)
 1688                 return (NODEV);
 1689         return (cdev2priv(x)->cdp_inode);
 1690 }
 1691 
 1692 static struct fileops devfs_ops_f = {
 1693         .fo_read =      devfs_read_f,
 1694         .fo_write =     devfs_write_f,
 1695         .fo_truncate =  devfs_truncate_f,
 1696         .fo_ioctl =     devfs_ioctl_f,
 1697         .fo_poll =      devfs_poll_f,
 1698         .fo_kqfilter =  devfs_kqfilter_f,
 1699         .fo_stat =      devfs_stat_f,
 1700         .fo_close =     devfs_close_f,
 1701         .fo_chmod =     vn_chmod,
 1702         .fo_chown =     vn_chown,
 1703         .fo_sendfile =  vn_sendfile,
 1704         .fo_seek =      vn_seek,
 1705         .fo_flags =     DFLAG_PASSABLE | DFLAG_SEEKABLE
 1706 };
 1707 
 1708 static struct vop_vector devfs_vnodeops = {
 1709         .vop_default =          &default_vnodeops,
 1710 
 1711         .vop_access =           devfs_access,
 1712         .vop_getattr =          devfs_getattr,
 1713         .vop_ioctl =            devfs_rioctl,
 1714         .vop_lookup =           devfs_lookup,
 1715         .vop_mknod =            devfs_mknod,
 1716         .vop_pathconf =         devfs_pathconf,
 1717         .vop_read =             devfs_rread,
 1718         .vop_readdir =          devfs_readdir,
 1719         .vop_readlink =         devfs_readlink,
 1720         .vop_reclaim =          devfs_reclaim,
 1721         .vop_remove =           devfs_remove,
 1722         .vop_revoke =           devfs_revoke,
 1723         .vop_setattr =          devfs_setattr,
 1724 #ifdef MAC
 1725         .vop_setlabel =         devfs_setlabel,
 1726 #endif
 1727         .vop_symlink =          devfs_symlink,
 1728         .vop_vptocnp =          devfs_vptocnp,
 1729 };
 1730 
 1731 static struct vop_vector devfs_specops = {
 1732         .vop_default =          &default_vnodeops,
 1733 
 1734         .vop_access =           devfs_access,
 1735         .vop_bmap =             VOP_PANIC,
 1736         .vop_close =            devfs_close,
 1737         .vop_create =           VOP_PANIC,
 1738         .vop_fsync =            devfs_fsync,
 1739         .vop_getattr =          devfs_getattr,
 1740         .vop_link =             VOP_PANIC,
 1741         .vop_mkdir =            VOP_PANIC,
 1742         .vop_mknod =            VOP_PANIC,
 1743         .vop_open =             devfs_open,
 1744         .vop_pathconf =         devfs_pathconf,
 1745         .vop_print =            devfs_print,
 1746         .vop_read =             VOP_PANIC,
 1747         .vop_readdir =          VOP_PANIC,
 1748         .vop_readlink =         VOP_PANIC,
 1749         .vop_reallocblks =      VOP_PANIC,
 1750         .vop_reclaim =          devfs_reclaim,
 1751         .vop_remove =           devfs_remove,
 1752         .vop_rename =           VOP_PANIC,
 1753         .vop_revoke =           devfs_revoke,
 1754         .vop_rmdir =            VOP_PANIC,
 1755         .vop_setattr =          devfs_setattr,
 1756 #ifdef MAC
 1757         .vop_setlabel =         devfs_setlabel,
 1758 #endif
 1759         .vop_strategy =         VOP_PANIC,
 1760         .vop_symlink =          VOP_PANIC,
 1761         .vop_vptocnp =          devfs_vptocnp,
 1762         .vop_write =            VOP_PANIC,
 1763 };
 1764 
 1765 /*
 1766  * Our calling convention to the device drivers used to be that we passed
 1767  * vnode.h IO_* flags to read()/write(), but we're moving to fcntl.h O_ 
 1768  * flags instead since that's what open(), close() and ioctl() takes and
 1769  * we don't really want vnode.h in device drivers.
 1770  * We solved the source compatibility by redefining some vnode flags to
 1771  * be the same as the fcntl ones and by sending down the bitwise OR of
 1772  * the respective fcntl/vnode flags.  These CTASSERTS make sure nobody
 1773  * pulls the rug out under this.
 1774  */
 1775 CTASSERT(O_NONBLOCK == IO_NDELAY);
 1776 CTASSERT(O_FSYNC == IO_SYNC);
Cache object: b52c10e3097733af6f3e9924c9b529ec
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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
