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

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    1 /*-
    2  * Copyright (c) 1992, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * This code is derived from software donated to Berkeley by
    6  * Jan-Simon Pendry.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 4. Neither the name of the University nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  *
   32  *      @(#)portal_vnops.c      8.14 (Berkeley) 5/21/95
   33  *
   34  * $FreeBSD$
   35  */
   36 
   37 /*
   38  * Portal Filesystem
   39  */
   40 
   41 #include <sys/param.h>
   42 #include <sys/fcntl.h>
   43 #include <sys/file.h>
   44 #include <sys/kernel.h>
   45 #include <sys/lock.h>
   46 #include <sys/malloc.h>
   47 #include <sys/mbuf.h>
   48 #include <sys/mount.h>
   49 #include <sys/mutex.h>
   50 #include <sys/namei.h>
   51 #include <sys/proc.h>
   52 #include <sys/socket.h>
   53 #include <sys/socketvar.h>
   54 #include <sys/stat.h>
   55 #include <sys/syscallsubr.h>
   56 #include <sys/systm.h>
   57 #include <sys/un.h>
   58 #include <sys/unpcb.h>
   59 #include <sys/vnode.h>
   60 
   61 #include <fs/portalfs/portal.h>
   62 
   63 static int portal_fileid = PORTAL_ROOTFILEID+1;
   64 
   65 static void     portal_closefd(struct thread *td, int fd);
   66 static int      portal_connect(struct socket *so, struct socket *so2);
   67 static vop_getattr_t    portal_getattr;
   68 static vop_lookup_t     portal_lookup;
   69 static vop_open_t       portal_open;
   70 static vop_readdir_t    portal_readdir;
   71 static vop_reclaim_t    portal_reclaim;
   72 static vop_setattr_t    portal_setattr;
   73 
   74 static void
   75 portal_closefd(td, fd)
   76         struct thread *td;
   77         int fd;
   78 {
   79         int error;
   80 
   81         error = kern_close(td, fd);
   82         /*
   83          * We should never get an error, and there isn't anything
   84          * we could do if we got one, so just print a message.
   85          */
   86         if (error)
   87                 printf("portal_closefd: error = %d\n", error);
   88 }
   89 
   90 /*
   91  * vp is the current namei directory
   92  * cnp is the name to locate in that directory...
   93  */
   94 static int
   95 portal_lookup(ap)
   96         struct vop_lookup_args /* {
   97                 struct vnode * a_dvp;
   98                 struct vnode ** a_vpp;
   99                 struct componentname * a_cnp;
  100         } */ *ap;
  101 {
  102         struct componentname *cnp = ap->a_cnp;
  103         struct vnode **vpp = ap->a_vpp;
  104         struct vnode *dvp = ap->a_dvp;
  105         char *pname = cnp->cn_nameptr;
  106         struct thread *td = cnp->cn_thread;
  107         struct portalnode *pt;
  108         int error;
  109         struct vnode *fvp = 0;
  110         char *path;
  111         int size;
  112 
  113         *vpp = NULLVP;
  114 
  115         if (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)
  116                 return (EROFS);
  117 
  118         if (cnp->cn_namelen == 1 && *pname == '.') {
  119                 *vpp = dvp;
  120                 VREF(dvp);
  121                 return (0);
  122         }
  123         KASSERT((cnp->cn_flags & ISDOTDOT) == 0,
  124             ("portal_lookup: Can not handle dotdot lookups."));
  125 
  126         /*
  127          * Do the MALLOC before the getnewvnode since doing so afterward
  128          * might cause a bogus v_data pointer to get dereferenced
  129          * elsewhere if MALLOC should block.
  130          */
  131         MALLOC(pt, struct portalnode *, sizeof(struct portalnode),
  132                 M_TEMP, M_WAITOK);
  133 
  134         error = getnewvnode("portal", dvp->v_mount, &portal_vnodeops, &fvp);
  135         if (error) {
  136                 FREE(pt, M_TEMP);
  137                 goto bad;
  138         }
  139         fvp->v_type = VREG;
  140         fvp->v_data = pt;
  141         /*
  142          * Save all of the remaining pathname and
  143          * advance the namei next pointer to the end
  144          * of the string.
  145          */
  146         for (size = 0, path = pname; *path; path++)
  147                 size++;
  148         cnp->cn_consume = size - cnp->cn_namelen;
  149 
  150         pt->pt_arg = malloc(size+1, M_TEMP, M_WAITOK);
  151         pt->pt_size = size+1;
  152         bcopy(pname, pt->pt_arg, pt->pt_size);
  153         pt->pt_fileid = portal_fileid++;
  154 
  155         *vpp = fvp;
  156         vn_lock(fvp, LK_EXCLUSIVE | LK_RETRY, td);
  157         error = insmntque(fvp, dvp->v_mount);
  158         if (error != 0) {
  159                 *vpp = NULLVP;
  160                 return (error);
  161         }
  162         return (0);
  163 
  164 bad:;
  165         if (fvp)
  166                 vrele(fvp);
  167         return (error);
  168 }
  169 
  170 static int
  171 portal_connect(so, so2)
  172         struct socket *so;
  173         struct socket *so2;
  174 {
  175         /* from unp_connect, bypassing the namei stuff... */
  176         struct socket *so3;
  177         struct unpcb *unp2;
  178         struct unpcb *unp3;
  179 
  180         if (so2 == 0)
  181                 return (ECONNREFUSED);
  182 
  183         if (so->so_type != so2->so_type)
  184                 return (EPROTOTYPE);
  185 
  186         if ((so2->so_options & SO_ACCEPTCONN) == 0)
  187                 return (ECONNREFUSED);
  188 
  189         if ((so3 = sonewconn(so2, 0)) == 0)
  190                 return (ECONNREFUSED);
  191 
  192         unp2 = sotounpcb(so2);
  193         unp3 = sotounpcb(so3);
  194         if (unp2->unp_addr)
  195                 unp3->unp_addr = (struct sockaddr_un *)
  196                     sodupsockaddr((struct sockaddr *)unp2->unp_addr,
  197                     M_NOWAIT);
  198         so2 = so3;
  199 
  200         return (soconnect2(so, so2));
  201 }
  202 
  203 static int
  204 portal_open(ap)
  205         struct vop_open_args /* {
  206                 struct vnode *a_vp;
  207                 int  a_mode;
  208                 struct ucred *a_cred;
  209                 struct thread *a_td;
  210         } */ *ap;
  211 {
  212         struct socket *so = 0;
  213         struct portalnode *pt;
  214         struct thread *td = ap->a_td;
  215         struct vnode *vp = ap->a_vp;
  216         struct uio auio;
  217         struct iovec aiov[2];
  218         int res;
  219         struct mbuf *cm = 0;
  220         struct cmsghdr *cmsg;
  221         int newfds;
  222         int *ip;
  223         int fd;
  224         int error;
  225         int len;
  226         struct portalmount *fmp;
  227         struct file *fp;
  228         struct portal_cred pcred;
  229 
  230         /*
  231          * Nothing to do when opening the root node.
  232          */
  233         if (vp->v_vflag & VV_ROOT)
  234                 return (0);
  235 
  236         /*
  237          * Can't be opened unless the caller is set up
  238          * to deal with the side effects.  Check for this
  239          * by testing whether td_dupfd has been set.
  240          */
  241         if (td->td_dupfd >= 0)
  242                 return (ENODEV);
  243 
  244         pt = VTOPORTAL(vp);
  245         fmp = VFSTOPORTAL(vp->v_mount);
  246 
  247         /*
  248          * Create a new socket.
  249          */
  250         error = socreate(AF_UNIX, &so, SOCK_STREAM, 0, ap->a_td->td_ucred,
  251             ap->a_td);
  252         if (error)
  253                 goto bad;
  254 
  255         /*
  256          * Reserve some buffer space
  257          */
  258         res = pt->pt_size + sizeof(pcred) + 512;        /* XXX */
  259         error = soreserve(so, res, res);
  260         if (error)
  261                 goto bad;
  262 
  263         /*
  264          * Kick off connection
  265          */
  266         error = portal_connect(so, fmp->pm_server->f_data);
  267         if (error)
  268                 goto bad;
  269 
  270         /*
  271          * Wait for connection to complete
  272          */
  273         /*
  274          * XXX: Since the mount point is holding a reference on the
  275          * underlying server socket, it is not easy to find out whether
  276          * the server process is still running.  To handle this problem
  277          * we loop waiting for the new socket to be connected (something
  278          * which will only happen if the server is still running) or for
  279          * the reference count on the server socket to drop to 1, which
  280          * will happen if the server dies.  Sleep for 5 second intervals
  281          * and keep polling the reference count.   XXX.
  282          */
  283         SOCK_LOCK(so);
  284         while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
  285                 if (fmp->pm_server->f_count == 1) {
  286                         SOCK_UNLOCK(so);
  287                         error = ECONNREFUSED;
  288                         goto bad;
  289                 }
  290                 (void) msleep((caddr_t) &so->so_timeo, SOCK_MTX(so), PSOCK,
  291                     "portalcon", 5 * hz);
  292         }
  293         SOCK_UNLOCK(so);
  294 
  295         if (so->so_error) {
  296                 error = so->so_error;
  297                 goto bad;
  298         }
  299 
  300         /*
  301          * Set miscellaneous flags
  302          */
  303         SOCKBUF_LOCK(&so->so_rcv);
  304         so->so_rcv.sb_timeo = 0;
  305         so->so_rcv.sb_flags |= SB_NOINTR;
  306         SOCKBUF_UNLOCK(&so->so_rcv);
  307         SOCKBUF_LOCK(&so->so_snd);
  308         so->so_snd.sb_timeo = 0;
  309         so->so_snd.sb_flags |= SB_NOINTR;
  310         SOCKBUF_UNLOCK(&so->so_snd);
  311 
  312 
  313         pcred.pcr_flag = ap->a_mode;
  314         pcred.pcr_uid = ap->a_cred->cr_uid;
  315         pcred.pcr_ngroups = ap->a_cred->cr_ngroups;
  316         bcopy(ap->a_cred->cr_groups, pcred.pcr_groups, NGROUPS * sizeof(gid_t));
  317         aiov[0].iov_base = (caddr_t) &pcred;
  318         aiov[0].iov_len = sizeof(pcred);
  319         aiov[1].iov_base = pt->pt_arg;
  320         aiov[1].iov_len = pt->pt_size;
  321         auio.uio_iov = aiov;
  322         auio.uio_iovcnt = 2;
  323         auio.uio_rw = UIO_WRITE;
  324         auio.uio_segflg = UIO_SYSSPACE;
  325         auio.uio_td = td;
  326         auio.uio_offset = 0;
  327         auio.uio_resid = aiov[0].iov_len + aiov[1].iov_len;
  328 
  329         error = sosend(so, (struct sockaddr *) 0, &auio,
  330                         (struct mbuf *) 0, (struct mbuf *) 0, 0 , td);
  331         if (error)
  332                 goto bad;
  333 
  334         len = auio.uio_resid = sizeof(int);
  335         do {
  336                 struct mbuf *m = 0;
  337                 int flags = MSG_WAITALL;
  338                 error = soreceive(so, (struct sockaddr **) 0, &auio,
  339                                         &m, &cm, &flags);
  340                 if (error)
  341                         goto bad;
  342 
  343                 /*
  344                  * Grab an error code from the mbuf.
  345                  */
  346                 if (m) {
  347                         m = m_pullup(m, sizeof(int));   /* Needed? */
  348                         if (m) {
  349                                 error = *(mtod(m, int *));
  350                                 m_freem(m);
  351                         } else {
  352                                 error = EINVAL;
  353                         }
  354                 } else {
  355                         if (cm == 0) {
  356                                 error = ECONNRESET;      /* XXX */
  357 #ifdef notdef
  358                                 break;
  359 #endif
  360                         }
  361                 }
  362         } while (cm == 0 && auio.uio_resid == len && !error);
  363 
  364         if (cm == 0)
  365                 goto bad;
  366 
  367         if (auio.uio_resid) {
  368                 error = 0;
  369 #ifdef notdef
  370                 error = EMSGSIZE;
  371                 goto bad;
  372 #endif
  373         }
  374 
  375         /*
  376          * XXX: Break apart the control message, and retrieve the
  377          * received file descriptor.  Note that more than one descriptor
  378          * may have been received, or that the rights chain may have more
  379          * than a single mbuf in it.  What to do?
  380          */
  381         cmsg = mtod(cm, struct cmsghdr *);
  382         newfds = (cmsg->cmsg_len - sizeof(*cmsg)) / sizeof (int);
  383         if (newfds == 0) {
  384                 error = ECONNREFUSED;
  385                 goto bad;
  386         }
  387         /*
  388          * At this point the rights message consists of a control message
  389          * header, followed by a data region containing a vector of
  390          * integer file descriptors.  The fds were allocated by the action
  391          * of receiving the control message.
  392          */
  393         ip = (int *) (cmsg + 1);
  394         fd = *ip++;
  395         if (newfds > 1) {
  396                 /*
  397                  * Close extra fds.
  398                  */
  399                 int i;
  400                 printf("portal_open: %d extra fds\n", newfds - 1);
  401                 for (i = 1; i < newfds; i++) {
  402                         portal_closefd(td, *ip);
  403                         ip++;
  404                 }
  405         }
  406 
  407         /*
  408          * Check that the mode the file is being opened for is a subset
  409          * of the mode of the existing descriptor.
  410          */
  411         if ((error = fget(td, fd, &fp)) != 0)
  412                 goto bad;
  413         if (((ap->a_mode & (FREAD|FWRITE)) | fp->f_flag) != fp->f_flag) {
  414                 fdrop(fp, td);
  415                 portal_closefd(td, fd);
  416                 error = EACCES;
  417                 goto bad;
  418         }
  419         fdrop(fp, td);
  420 
  421         /*
  422          * Save the dup fd in the proc structure then return the
  423          * special error code (ENXIO) which causes magic things to
  424          * happen in vn_open.  The whole concept is, well, hmmm.
  425          */
  426         td->td_dupfd = fd;
  427         error = ENXIO;
  428 
  429 bad:;
  430         /*
  431          * And discard the control message.
  432          */
  433         if (cm) {
  434                 m_freem(cm);
  435         }
  436 
  437         if (so) {
  438                 soshutdown(so, 2);
  439                 soclose(so);
  440         }
  441         return (error);
  442 }
  443 
  444 static int
  445 portal_getattr(ap)
  446         struct vop_getattr_args /* {
  447                 struct vnode *a_vp;
  448                 struct vattr *a_vap;
  449                 struct ucred *a_cred;
  450                 struct thread *a_td;
  451         } */ *ap;
  452 {
  453         struct vnode *vp = ap->a_vp;
  454         struct vattr *vap = ap->a_vap;
  455 
  456         vap->va_uid = 0;
  457         vap->va_gid = 0;
  458         vap->va_size = DEV_BSIZE;
  459         vap->va_blocksize = DEV_BSIZE;
  460         nanotime(&vap->va_atime);
  461         vap->va_mtime = vap->va_atime;
  462         vap->va_ctime = vap->va_mtime;
  463         vap->va_gen = 0;
  464         vap->va_flags = 0;
  465         vap->va_rdev = NODEV;
  466         /* vap->va_qbytes = 0; */
  467         vap->va_bytes = 0;
  468         vap->va_filerev = 0;
  469         /* vap->va_qsize = 0; */
  470         if (vp->v_vflag & VV_ROOT) {
  471                 vap->va_type = VDIR;
  472                 vap->va_mode = S_IRUSR|S_IWUSR|S_IXUSR|
  473                                 S_IRGRP|S_IWGRP|S_IXGRP|
  474                                 S_IROTH|S_IWOTH|S_IXOTH;
  475                 vap->va_nlink = 2;
  476                 vap->va_fileid = 2;
  477         } else {
  478                 vap->va_type = VREG;
  479                 vap->va_mode = S_IRUSR|S_IWUSR|
  480                                 S_IRGRP|S_IWGRP|
  481                                 S_IROTH|S_IWOTH;
  482                 vap->va_nlink = 1;
  483                 vap->va_fileid = VTOPORTAL(vp)->pt_fileid;
  484         }
  485         return (0);
  486 }
  487 
  488 static int
  489 portal_setattr(ap)
  490         struct vop_setattr_args /* {
  491                 struct vnode *a_vp;
  492                 struct vattr *a_vap;
  493                 struct ucred *a_cred;
  494                 struct thread *a_td;
  495         } */ *ap;
  496 {
  497 
  498         /*
  499          * Can't mess with the root vnode
  500          */
  501         if (ap->a_vp->v_vflag & VV_ROOT)
  502                 return (EACCES);
  503 
  504         if (ap->a_vap->va_flags != VNOVAL)
  505                 return (EOPNOTSUPP);
  506 
  507         return (0);
  508 }
  509 
  510 /*
  511  * Fake readdir, just return empty directory.
  512  * It is hard to deal with '.' and '..' so don't bother.
  513  */
  514 static int
  515 portal_readdir(ap)
  516         struct vop_readdir_args /* {
  517                 struct vnode *a_vp;
  518                 struct uio *a_uio;
  519                 struct ucred *a_cred;
  520                 int *a_eofflag;
  521                 u_long *a_cookies;
  522                 int a_ncookies;
  523         } */ *ap;
  524 {
  525 
  526         /*
  527          * We don't allow exporting portal mounts, and currently local
  528          * requests do not need cookies.
  529          */
  530         if (ap->a_ncookies)
  531                 panic("portal_readdir: not hungry");
  532 
  533         return (0);
  534 }
  535 
  536 static int
  537 portal_reclaim(ap)
  538         struct vop_reclaim_args /* {
  539                 struct vnode *a_vp;
  540         } */ *ap;
  541 {
  542         struct portalnode *pt = VTOPORTAL(ap->a_vp);
  543 
  544         if (pt->pt_arg) {
  545                 free((caddr_t) pt->pt_arg, M_TEMP);
  546                 pt->pt_arg = 0;
  547         }
  548         FREE(ap->a_vp->v_data, M_TEMP);
  549         ap->a_vp->v_data = 0;
  550 
  551         return (0);
  552 }
  553 
  554 struct vop_vector portal_vnodeops = {
  555         .vop_default =          &default_vnodeops,
  556 
  557         .vop_access =           VOP_NULL,
  558         .vop_getattr =          portal_getattr,
  559         .vop_lookup =           portal_lookup,
  560         .vop_open =             portal_open,
  561         .vop_pathconf =         vop_stdpathconf,
  562         .vop_readdir =          portal_readdir,
  563         .vop_reclaim =          portal_reclaim,
  564         .vop_setattr =          portal_setattr,
  565 };

Cache object: ea9962ccd2ecdb11d83fc1bbecb075f7


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