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

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    1 /*-
    2  * Copyright (c) 2001 Dag-Erling Coïdan Smørgrav
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer
   10  *    in this position and unchanged.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  * 3. The name of the author may not be used to endorse or promote products
   15  *    derived from this software without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD: releng/10.4/sys/fs/pseudofs/pseudofs_vnops.c 297267 2016-03-25 08:26:37Z kib $");
   31 
   32 #include "opt_pseudofs.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/kernel.h>
   36 #include <sys/systm.h>
   37 #include <sys/ctype.h>
   38 #include <sys/dirent.h>
   39 #include <sys/fcntl.h>
   40 #include <sys/limits.h>
   41 #include <sys/lock.h>
   42 #include <sys/malloc.h>
   43 #include <sys/mount.h>
   44 #include <sys/mutex.h>
   45 #include <sys/namei.h>
   46 #include <sys/proc.h>
   47 #include <sys/sbuf.h>
   48 #include <sys/sx.h>
   49 #include <sys/sysctl.h>
   50 #include <sys/vnode.h>
   51 
   52 #include <fs/pseudofs/pseudofs.h>
   53 #include <fs/pseudofs/pseudofs_internal.h>
   54 
   55 #define KASSERT_PN_IS_DIR(pn)                                           \
   56         KASSERT((pn)->pn_type == pfstype_root ||                        \
   57             (pn)->pn_type == pfstype_dir ||                             \
   58             (pn)->pn_type == pfstype_procdir,                           \
   59             ("%s(): VDIR vnode refers to non-directory pfs_node", __func__))
   60 
   61 #define KASSERT_PN_IS_FILE(pn)                                          \
   62         KASSERT((pn)->pn_type == pfstype_file,                          \
   63             ("%s(): VREG vnode refers to non-file pfs_node", __func__))
   64 
   65 #define KASSERT_PN_IS_LINK(pn)                                          \
   66         KASSERT((pn)->pn_type == pfstype_symlink,                       \
   67             ("%s(): VLNK vnode refers to non-link pfs_node", __func__))
   68 
   69 /*
   70  * Returns the fileno, adjusted for target pid
   71  */
   72 static uint32_t
   73 pn_fileno(struct pfs_node *pn, pid_t pid)
   74 {
   75 
   76         KASSERT(pn->pn_fileno > 0,
   77             ("%s(): no fileno allocated", __func__));
   78         if (pid != NO_PID)
   79                 return (pn->pn_fileno * NO_PID + pid);
   80         return (pn->pn_fileno);
   81 }
   82 
   83 /*
   84  * Returns non-zero if given file is visible to given thread.
   85  */
   86 static int
   87 pfs_visible_proc(struct thread *td, struct pfs_node *pn, struct proc *proc)
   88 {
   89         int visible;
   90 
   91         if (proc == NULL)
   92                 return (0);
   93 
   94         PROC_LOCK_ASSERT(proc, MA_OWNED);
   95 
   96         visible = ((proc->p_flag & P_WEXIT) == 0);
   97         if (visible)
   98                 visible = (p_cansee(td, proc) == 0);
   99         if (visible && pn->pn_vis != NULL)
  100                 visible = pn_vis(td, proc, pn);
  101         if (!visible)
  102                 return (0);
  103         return (1);
  104 }
  105 
  106 static int
  107 pfs_visible(struct thread *td, struct pfs_node *pn, pid_t pid,
  108     bool allproc_locked, struct proc **p)
  109 {
  110         struct proc *proc;
  111 
  112         PFS_TRACE(("%s (pid: %d, req: %d)",
  113             pn->pn_name, pid, td->td_proc->p_pid));
  114 
  115         if (p)
  116                 *p = NULL;
  117         if (pid == NO_PID)
  118                 PFS_RETURN (1);
  119         proc = allproc_locked ? pfind_locked(pid) : pfind(pid);
  120         if (proc == NULL)
  121                 PFS_RETURN (0);
  122         if (pfs_visible_proc(td, pn, proc)) {
  123                 if (p)
  124                         *p = proc;
  125                 else
  126                         PROC_UNLOCK(proc);
  127                 PFS_RETURN (1);
  128         }
  129         PROC_UNLOCK(proc);
  130         PFS_RETURN (0);
  131 }
  132 
  133 /*
  134  * Verify permissions
  135  */
  136 static int
  137 pfs_access(struct vop_access_args *va)
  138 {
  139         struct vnode *vn = va->a_vp;
  140         struct pfs_vdata *pvd = vn->v_data;
  141         struct vattr vattr;
  142         int error;
  143 
  144         PFS_TRACE(("%s", pvd->pvd_pn->pn_name));
  145         (void)pvd;
  146 
  147         error = VOP_GETATTR(vn, &vattr, va->a_cred);
  148         if (error)
  149                 PFS_RETURN (error);
  150         error = vaccess(vn->v_type, vattr.va_mode, vattr.va_uid,
  151             vattr.va_gid, va->a_accmode, va->a_cred, NULL);
  152         PFS_RETURN (error);
  153 }
  154 
  155 /*
  156  * Close a file or directory
  157  */
  158 static int
  159 pfs_close(struct vop_close_args *va)
  160 {
  161         struct vnode *vn = va->a_vp;
  162         struct pfs_vdata *pvd = vn->v_data;
  163         struct pfs_node *pn = pvd->pvd_pn;
  164         struct proc *proc;
  165         int error;
  166 
  167         PFS_TRACE(("%s", pn->pn_name));
  168         pfs_assert_not_owned(pn);
  169 
  170         /*
  171          * Do nothing unless this is the last close and the node has a
  172          * last-close handler.
  173          */
  174         if (vrefcnt(vn) > 1 || pn->pn_close == NULL)
  175                 PFS_RETURN (0);
  176 
  177         if (pvd->pvd_pid != NO_PID) {
  178                 proc = pfind(pvd->pvd_pid);
  179         } else {
  180                 proc = NULL;
  181         }
  182 
  183         error = pn_close(va->a_td, proc, pn);
  184 
  185         if (proc != NULL)
  186                 PROC_UNLOCK(proc);
  187 
  188         PFS_RETURN (error);
  189 }
  190 
  191 /*
  192  * Get file attributes
  193  */
  194 static int
  195 pfs_getattr(struct vop_getattr_args *va)
  196 {
  197         struct vnode *vn = va->a_vp;
  198         struct pfs_vdata *pvd = vn->v_data;
  199         struct pfs_node *pn = pvd->pvd_pn;
  200         struct vattr *vap = va->a_vap;
  201         struct proc *proc;
  202         int error = 0;
  203 
  204         PFS_TRACE(("%s", pn->pn_name));
  205         pfs_assert_not_owned(pn);
  206 
  207         if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
  208                 PFS_RETURN (ENOENT);
  209 
  210         vap->va_type = vn->v_type;
  211         vap->va_fileid = pn_fileno(pn, pvd->pvd_pid);
  212         vap->va_flags = 0;
  213         vap->va_blocksize = PAGE_SIZE;
  214         vap->va_bytes = vap->va_size = 0;
  215         vap->va_filerev = 0;
  216         vap->va_fsid = vn->v_mount->mnt_stat.f_fsid.val[0];
  217         vap->va_nlink = 1;
  218         nanotime(&vap->va_ctime);
  219         vap->va_atime = vap->va_mtime = vap->va_ctime;
  220 
  221         switch (pn->pn_type) {
  222         case pfstype_procdir:
  223         case pfstype_root:
  224         case pfstype_dir:
  225 #if 0
  226                 pfs_lock(pn);
  227                 /* compute link count */
  228                 pfs_unlock(pn);
  229 #endif
  230                 vap->va_mode = 0555;
  231                 break;
  232         case pfstype_file:
  233         case pfstype_symlink:
  234                 vap->va_mode = 0444;
  235                 break;
  236         default:
  237                 printf("shouldn't be here!\n");
  238                 vap->va_mode = 0;
  239                 break;
  240         }
  241 
  242         if (proc != NULL) {
  243                 vap->va_uid = proc->p_ucred->cr_ruid;
  244                 vap->va_gid = proc->p_ucred->cr_rgid;
  245         } else {
  246                 vap->va_uid = 0;
  247                 vap->va_gid = 0;
  248         }
  249 
  250         if (pn->pn_attr != NULL)
  251                 error = pn_attr(curthread, proc, pn, vap);
  252 
  253         if(proc != NULL)
  254                 PROC_UNLOCK(proc);
  255 
  256         PFS_RETURN (error);
  257 }
  258 
  259 /*
  260  * Perform an ioctl
  261  */
  262 static int
  263 pfs_ioctl(struct vop_ioctl_args *va)
  264 {
  265         struct vnode *vn;
  266         struct pfs_vdata *pvd;
  267         struct pfs_node *pn;
  268         struct proc *proc;
  269         int error;
  270 
  271         vn = va->a_vp;
  272         vn_lock(vn, LK_SHARED | LK_RETRY);
  273         if (vn->v_iflag & VI_DOOMED) {
  274                 VOP_UNLOCK(vn, 0);
  275                 return (EBADF);
  276         }
  277         pvd = vn->v_data;
  278         pn = pvd->pvd_pn;
  279 
  280         PFS_TRACE(("%s: %lx", pn->pn_name, va->a_command));
  281         pfs_assert_not_owned(pn);
  282 
  283         if (vn->v_type != VREG) {
  284                 VOP_UNLOCK(vn, 0);
  285                 PFS_RETURN (EINVAL);
  286         }
  287         KASSERT_PN_IS_FILE(pn);
  288 
  289         if (pn->pn_ioctl == NULL) {
  290                 VOP_UNLOCK(vn, 0);
  291                 PFS_RETURN (ENOTTY);
  292         }
  293 
  294         /*
  295          * This is necessary because process' privileges may
  296          * have changed since the open() call.
  297          */
  298         if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc)) {
  299                 VOP_UNLOCK(vn, 0);
  300                 PFS_RETURN (EIO);
  301         }
  302 
  303         error = pn_ioctl(curthread, proc, pn, va->a_command, va->a_data);
  304 
  305         if (proc != NULL)
  306                 PROC_UNLOCK(proc);
  307 
  308         VOP_UNLOCK(vn, 0);
  309         PFS_RETURN (error);
  310 }
  311 
  312 /*
  313  * Perform getextattr
  314  */
  315 static int
  316 pfs_getextattr(struct vop_getextattr_args *va)
  317 {
  318         struct vnode *vn = va->a_vp;
  319         struct pfs_vdata *pvd = vn->v_data;
  320         struct pfs_node *pn = pvd->pvd_pn;
  321         struct proc *proc;
  322         int error;
  323 
  324         PFS_TRACE(("%s", pn->pn_name));
  325         pfs_assert_not_owned(pn);
  326 
  327         /*
  328          * This is necessary because either process' privileges may
  329          * have changed since the open() call.
  330          */
  331         if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
  332                 PFS_RETURN (EIO);
  333 
  334         if (pn->pn_getextattr == NULL)
  335                 error = EOPNOTSUPP;
  336         else
  337                 error = pn_getextattr(curthread, proc, pn,
  338                     va->a_attrnamespace, va->a_name, va->a_uio,
  339                     va->a_size, va->a_cred);
  340 
  341         if (proc != NULL)
  342                 PROC_UNLOCK(proc);
  343 
  344         PFS_RETURN (error);
  345 }
  346 
  347 /*
  348  * Convert a vnode to its component name
  349  */
  350 static int
  351 pfs_vptocnp(struct vop_vptocnp_args *ap)
  352 {
  353         struct vnode *vp = ap->a_vp;
  354         struct vnode **dvp = ap->a_vpp;
  355         struct pfs_vdata *pvd = vp->v_data;
  356         struct pfs_node *pd = pvd->pvd_pn;
  357         struct pfs_node *pn;
  358         struct mount *mp;
  359         char *buf = ap->a_buf;
  360         int *buflen = ap->a_buflen;
  361         char pidbuf[PFS_NAMELEN];
  362         pid_t pid = pvd->pvd_pid;
  363         int len, i, error, locked;
  364 
  365         i = *buflen;
  366         error = 0;
  367 
  368         pfs_lock(pd);
  369 
  370         if (vp->v_type == VDIR && pd->pn_type == pfstype_root) {
  371                 *dvp = vp;
  372                 vhold(*dvp);
  373                 pfs_unlock(pd);
  374                 PFS_RETURN (0);
  375         } else if (vp->v_type == VDIR && pd->pn_type == pfstype_procdir) {
  376                 len = snprintf(pidbuf, sizeof(pidbuf), "%d", pid);
  377                 i -= len;
  378                 if (i < 0) {
  379                         error = ENOMEM;
  380                         goto failed;
  381                 }
  382                 bcopy(pidbuf, buf + i, len);
  383         } else {
  384                 len = strlen(pd->pn_name);
  385                 i -= len;
  386                 if (i < 0) {
  387                         error = ENOMEM;
  388                         goto failed;
  389                 }
  390                 bcopy(pd->pn_name, buf + i, len);
  391         }
  392 
  393         pn = pd->pn_parent;
  394         pfs_unlock(pd);
  395 
  396         mp = vp->v_mount;
  397         error = vfs_busy(mp, 0);
  398         if (error)
  399                 return (error);
  400 
  401         /*
  402          * vp is held by caller.
  403          */
  404         locked = VOP_ISLOCKED(vp);
  405         VOP_UNLOCK(vp, 0);
  406 
  407         error = pfs_vncache_alloc(mp, dvp, pn, pid);
  408         if (error) {
  409                 vn_lock(vp, locked | LK_RETRY);
  410                 vfs_unbusy(mp);
  411                 PFS_RETURN(error);
  412         }
  413 
  414         *buflen = i;
  415         VOP_UNLOCK(*dvp, 0);
  416         vn_lock(vp, locked | LK_RETRY);
  417         vfs_unbusy(mp);
  418 
  419         PFS_RETURN (0);
  420 failed:
  421         pfs_unlock(pd);
  422         PFS_RETURN(error);
  423 }
  424 
  425 /*
  426  * Look up a file or directory
  427  */
  428 static int
  429 pfs_lookup(struct vop_cachedlookup_args *va)
  430 {
  431         struct vnode *vn = va->a_dvp;
  432         struct vnode **vpp = va->a_vpp;
  433         struct componentname *cnp = va->a_cnp;
  434         struct pfs_vdata *pvd = vn->v_data;
  435         struct pfs_node *pd = pvd->pvd_pn;
  436         struct pfs_node *pn, *pdn = NULL;
  437         struct mount *mp;
  438         pid_t pid = pvd->pvd_pid;
  439         char *pname;
  440         int error, i, namelen, visible;
  441 
  442         PFS_TRACE(("%.*s", (int)cnp->cn_namelen, cnp->cn_nameptr));
  443         pfs_assert_not_owned(pd);
  444 
  445         if (vn->v_type != VDIR)
  446                 PFS_RETURN (ENOTDIR);
  447         KASSERT_PN_IS_DIR(pd);
  448 
  449         error = VOP_ACCESS(vn, VEXEC, cnp->cn_cred, cnp->cn_thread);
  450         if (error)
  451                 PFS_RETURN (error);
  452 
  453         /*
  454          * Don't support DELETE or RENAME.  CREATE is supported so
  455          * that O_CREAT will work, but the lookup will still fail if
  456          * the file does not exist.
  457          */
  458         if ((cnp->cn_flags & ISLASTCN) &&
  459             (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
  460                 PFS_RETURN (EOPNOTSUPP);
  461 
  462         /* shortcut: check if the name is too long */
  463         if (cnp->cn_namelen >= PFS_NAMELEN)
  464                 PFS_RETURN (ENOENT);
  465 
  466         /* check that parent directory is visible... */
  467         if (!pfs_visible(curthread, pd, pvd->pvd_pid, false, NULL))
  468                 PFS_RETURN (ENOENT);
  469 
  470         /* self */
  471         namelen = cnp->cn_namelen;
  472         pname = cnp->cn_nameptr;
  473         if (namelen == 1 && pname[0] == '.') {
  474                 pn = pd;
  475                 *vpp = vn;
  476                 VREF(vn);
  477                 PFS_RETURN (0);
  478         }
  479 
  480         mp = vn->v_mount;
  481 
  482         /* parent */
  483         if (cnp->cn_flags & ISDOTDOT) {
  484                 if (pd->pn_type == pfstype_root)
  485                         PFS_RETURN (EIO);
  486                 error = vfs_busy(mp, MBF_NOWAIT);
  487                 if (error != 0) {
  488                         vfs_ref(mp);
  489                         VOP_UNLOCK(vn, 0);
  490                         error = vfs_busy(mp, 0);
  491                         vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
  492                         vfs_rel(mp);
  493                         if (error != 0)
  494                                 PFS_RETURN(ENOENT);
  495                         if (vn->v_iflag & VI_DOOMED) {
  496                                 vfs_unbusy(mp);
  497                                 PFS_RETURN(ENOENT);
  498                         }
  499                 }
  500                 VOP_UNLOCK(vn, 0);
  501                 KASSERT(pd->pn_parent != NULL,
  502                     ("%s(): non-root directory has no parent", __func__));
  503                 /*
  504                  * This one is tricky.  Descendents of procdir nodes
  505                  * inherit their parent's process affinity, but
  506                  * there's no easy reverse mapping.  For simplicity,
  507                  * we assume that if this node is a procdir, its
  508                  * parent isn't (which is correct as long as
  509                  * descendents of procdir nodes are never procdir
  510                  * nodes themselves)
  511                  */
  512                 if (pd->pn_type == pfstype_procdir)
  513                         pid = NO_PID;
  514                 pfs_lock(pd);
  515                 pn = pd->pn_parent;
  516                 pfs_unlock(pd);
  517                 goto got_pnode;
  518         }
  519 
  520         pfs_lock(pd);
  521 
  522         /* named node */
  523         for (pn = pd->pn_nodes; pn != NULL; pn = pn->pn_next)
  524                 if (pn->pn_type == pfstype_procdir)
  525                         pdn = pn;
  526                 else if (pn->pn_name[namelen] == '\0' &&
  527                     bcmp(pname, pn->pn_name, namelen) == 0) {
  528                         pfs_unlock(pd);
  529                         goto got_pnode;
  530                 }
  531 
  532         /* process dependent node */
  533         if ((pn = pdn) != NULL) {
  534                 pid = 0;
  535                 for (pid = 0, i = 0; i < namelen && isdigit(pname[i]); ++i)
  536                         if ((pid = pid * 10 + pname[i] - '') > PID_MAX)
  537                                 break;
  538                 if (i == cnp->cn_namelen) {
  539                         pfs_unlock(pd);
  540                         goto got_pnode;
  541                 }
  542         }
  543 
  544         pfs_unlock(pd);
  545 
  546         PFS_RETURN (ENOENT);
  547 
  548  got_pnode:
  549         pfs_assert_not_owned(pd);
  550         pfs_assert_not_owned(pn);
  551         visible = pfs_visible(curthread, pn, pid, false, NULL);
  552         if (!visible) {
  553                 error = ENOENT;
  554                 goto failed;
  555         }
  556 
  557         error = pfs_vncache_alloc(mp, vpp, pn, pid);
  558         if (error)
  559                 goto failed;
  560 
  561         if (cnp->cn_flags & ISDOTDOT) {
  562                 vfs_unbusy(mp);
  563                 vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
  564                 if (vn->v_iflag & VI_DOOMED) {
  565                         vput(*vpp);
  566                         *vpp = NULL;
  567                         PFS_RETURN(ENOENT);
  568                 }
  569         }
  570         if (cnp->cn_flags & MAKEENTRY && !(vn->v_iflag & VI_DOOMED))
  571                 cache_enter(vn, *vpp, cnp);
  572         PFS_RETURN (0);
  573  failed:
  574         if (cnp->cn_flags & ISDOTDOT) {
  575                 vfs_unbusy(mp);
  576                 vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
  577                 *vpp = NULL;
  578         }
  579         PFS_RETURN(error);
  580 }
  581 
  582 /*
  583  * Open a file or directory.
  584  */
  585 static int
  586 pfs_open(struct vop_open_args *va)
  587 {
  588         struct vnode *vn = va->a_vp;
  589         struct pfs_vdata *pvd = vn->v_data;
  590         struct pfs_node *pn = pvd->pvd_pn;
  591         int mode = va->a_mode;
  592 
  593         PFS_TRACE(("%s (mode 0x%x)", pn->pn_name, mode));
  594         pfs_assert_not_owned(pn);
  595 
  596         /* check if the requested mode is permitted */
  597         if (((mode & FREAD) && !(mode & PFS_RD)) ||
  598             ((mode & FWRITE) && !(mode & PFS_WR)))
  599                 PFS_RETURN (EPERM);
  600 
  601         /* we don't support locking */
  602         if ((mode & O_SHLOCK) || (mode & O_EXLOCK))
  603                 PFS_RETURN (EOPNOTSUPP);
  604 
  605         PFS_RETURN (0);
  606 }
  607 
  608 /*
  609  * Read from a file
  610  */
  611 static int
  612 pfs_read(struct vop_read_args *va)
  613 {
  614         struct vnode *vn = va->a_vp;
  615         struct pfs_vdata *pvd = vn->v_data;
  616         struct pfs_node *pn = pvd->pvd_pn;
  617         struct uio *uio = va->a_uio;
  618         struct proc *proc;
  619         struct sbuf *sb = NULL;
  620         int error, locked;
  621         off_t buflen;
  622 
  623         PFS_TRACE(("%s", pn->pn_name));
  624         pfs_assert_not_owned(pn);
  625 
  626         if (vn->v_type != VREG)
  627                 PFS_RETURN (EINVAL);
  628         KASSERT_PN_IS_FILE(pn);
  629 
  630         if (!(pn->pn_flags & PFS_RD))
  631                 PFS_RETURN (EBADF);
  632 
  633         if (pn->pn_fill == NULL)
  634                 PFS_RETURN (EIO);
  635 
  636         /*
  637          * This is necessary because either process' privileges may
  638          * have changed since the open() call.
  639          */
  640         if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
  641                 PFS_RETURN (EIO);
  642         if (proc != NULL) {
  643                 _PHOLD(proc);
  644                 PROC_UNLOCK(proc);
  645         }
  646 
  647         vhold(vn);
  648         locked = VOP_ISLOCKED(vn);
  649         VOP_UNLOCK(vn, 0);
  650 
  651         if (pn->pn_flags & PFS_RAWRD) {
  652                 PFS_TRACE(("%zd resid", uio->uio_resid));
  653                 error = pn_fill(curthread, proc, pn, NULL, uio);
  654                 PFS_TRACE(("%zd resid", uio->uio_resid));
  655                 goto ret;
  656         }
  657 
  658         if (uio->uio_resid < 0 || uio->uio_offset < 0 ||
  659             uio->uio_resid > OFF_MAX - uio->uio_offset) {
  660                 error = EINVAL;
  661                 goto ret;
  662         }
  663         buflen = uio->uio_offset + uio->uio_resid;
  664         if (buflen > MAXPHYS)
  665                 buflen = MAXPHYS;
  666 
  667         sb = sbuf_new(sb, NULL, buflen + 1, 0);
  668         if (sb == NULL) {
  669                 error = EIO;
  670                 goto ret;
  671         }
  672 
  673         error = pn_fill(curthread, proc, pn, sb, uio);
  674 
  675         if (error) {
  676                 sbuf_delete(sb);
  677                 goto ret;
  678         }
  679 
  680         /*
  681          * XXX: If the buffer overflowed, sbuf_len() will not return
  682          * the data length. Then just use the full length because an
  683          * overflowed sbuf must be full.
  684          */
  685         if (sbuf_finish(sb) == 0)
  686                 buflen = sbuf_len(sb);
  687         error = uiomove_frombuf(sbuf_data(sb), buflen, uio);
  688         sbuf_delete(sb);
  689 ret:
  690         vn_lock(vn, locked | LK_RETRY);
  691         vdrop(vn);
  692         if (proc != NULL)
  693                 PRELE(proc);
  694         PFS_RETURN (error);
  695 }
  696 
  697 /*
  698  * Iterate through directory entries
  699  */
  700 static int
  701 pfs_iterate(struct thread *td, struct proc *proc, struct pfs_node *pd,
  702             struct pfs_node **pn, struct proc **p)
  703 {
  704         int visible;
  705 
  706         sx_assert(&allproc_lock, SX_SLOCKED);
  707         pfs_assert_owned(pd);
  708  again:
  709         if (*pn == NULL) {
  710                 /* first node */
  711                 *pn = pd->pn_nodes;
  712         } else if ((*pn)->pn_type != pfstype_procdir) {
  713                 /* next node */
  714                 *pn = (*pn)->pn_next;
  715         }
  716         if (*pn != NULL && (*pn)->pn_type == pfstype_procdir) {
  717                 /* next process */
  718                 if (*p == NULL)
  719                         *p = LIST_FIRST(&allproc);
  720                 else
  721                         *p = LIST_NEXT(*p, p_list);
  722                 /* out of processes: next node */
  723                 if (*p == NULL)
  724                         *pn = (*pn)->pn_next;
  725                 else
  726                         PROC_LOCK(*p);
  727         }
  728 
  729         if ((*pn) == NULL)
  730                 return (-1);
  731 
  732         if (*p != NULL) {
  733                 visible = pfs_visible_proc(td, *pn, *p);
  734                 PROC_UNLOCK(*p);
  735         } else if (proc != NULL) {
  736                 visible = pfs_visible_proc(td, *pn, proc);
  737         } else {
  738                 visible = 1;
  739         }
  740         if (!visible)
  741                 goto again;
  742 
  743         return (0);
  744 }
  745 
  746 /* Directory entry list */
  747 struct pfsentry {
  748         STAILQ_ENTRY(pfsentry)  link;
  749         struct dirent           entry;
  750 };
  751 STAILQ_HEAD(pfsdirentlist, pfsentry);
  752 
  753 /*
  754  * Return directory entries.
  755  */
  756 static int
  757 pfs_readdir(struct vop_readdir_args *va)
  758 {
  759         struct vnode *vn = va->a_vp;
  760         struct pfs_vdata *pvd = vn->v_data;
  761         struct pfs_node *pd = pvd->pvd_pn;
  762         pid_t pid = pvd->pvd_pid;
  763         struct proc *p, *proc;
  764         struct pfs_node *pn;
  765         struct uio *uio;
  766         struct pfsentry *pfsent, *pfsent2;
  767         struct pfsdirentlist lst;
  768         off_t offset;
  769         int error, i, resid;
  770 
  771         STAILQ_INIT(&lst);
  772         error = 0;
  773         KASSERT(pd->pn_info == vn->v_mount->mnt_data,
  774             ("%s(): pn_info does not match mountpoint", __func__));
  775         PFS_TRACE(("%s pid %lu", pd->pn_name, (unsigned long)pid));
  776         pfs_assert_not_owned(pd);
  777 
  778         if (vn->v_type != VDIR)
  779                 PFS_RETURN (ENOTDIR);
  780         KASSERT_PN_IS_DIR(pd);
  781         uio = va->a_uio;
  782 
  783         /* only allow reading entire entries */
  784         offset = uio->uio_offset;
  785         resid = uio->uio_resid;
  786         if (offset < 0 || offset % PFS_DELEN != 0 ||
  787             (resid && resid < PFS_DELEN))
  788                 PFS_RETURN (EINVAL);
  789         if (resid == 0)
  790                 PFS_RETURN (0);
  791 
  792         sx_slock(&allproc_lock);
  793         pfs_lock(pd);
  794 
  795         /* check if the directory is visible to the caller */
  796         if (!pfs_visible(curthread, pd, pid, true, &proc)) {
  797                 sx_sunlock(&allproc_lock);
  798                 pfs_unlock(pd);
  799                 PFS_RETURN (ENOENT);
  800         }
  801         KASSERT(pid == NO_PID || proc != NULL,
  802             ("%s(): no process for pid %lu", __func__, (unsigned long)pid));
  803 
  804         /* skip unwanted entries */
  805         for (pn = NULL, p = NULL; offset > 0; offset -= PFS_DELEN) {
  806                 if (pfs_iterate(curthread, proc, pd, &pn, &p) == -1) {
  807                         /* nothing left... */
  808                         if (proc != NULL)
  809                                 PROC_UNLOCK(proc);
  810                         pfs_unlock(pd);
  811                         sx_sunlock(&allproc_lock);
  812                         PFS_RETURN (0);
  813                 }
  814         }
  815 
  816         /* fill in entries */
  817         while (pfs_iterate(curthread, proc, pd, &pn, &p) != -1 &&
  818             resid >= PFS_DELEN) {
  819                 if ((pfsent = malloc(sizeof(struct pfsentry), M_IOV,
  820                     M_NOWAIT | M_ZERO)) == NULL) {
  821                         error = ENOMEM;
  822                         break;
  823                 }
  824                 pfsent->entry.d_reclen = PFS_DELEN;
  825                 pfsent->entry.d_fileno = pn_fileno(pn, pid);
  826                 /* PFS_DELEN was picked to fit PFS_NAMLEN */
  827                 for (i = 0; i < PFS_NAMELEN - 1 && pn->pn_name[i] != '\0'; ++i)
  828                         pfsent->entry.d_name[i] = pn->pn_name[i];
  829                 pfsent->entry.d_name[i] = 0;
  830                 pfsent->entry.d_namlen = i;
  831                 switch (pn->pn_type) {
  832                 case pfstype_procdir:
  833                         KASSERT(p != NULL,
  834                             ("reached procdir node with p == NULL"));
  835                         pfsent->entry.d_namlen = snprintf(pfsent->entry.d_name,
  836                             PFS_NAMELEN, "%d", p->p_pid);
  837                         /* fall through */
  838                 case pfstype_root:
  839                 case pfstype_dir:
  840                 case pfstype_this:
  841                 case pfstype_parent:
  842                         pfsent->entry.d_type = DT_DIR;
  843                         break;
  844                 case pfstype_file:
  845                         pfsent->entry.d_type = DT_REG;
  846                         break;
  847                 case pfstype_symlink:
  848                         pfsent->entry.d_type = DT_LNK;
  849                         break;
  850                 default:
  851                         panic("%s has unexpected node type: %d", pn->pn_name, pn->pn_type);
  852                 }
  853                 PFS_TRACE(("%s", pfsent->entry.d_name));
  854                 STAILQ_INSERT_TAIL(&lst, pfsent, link);
  855                 offset += PFS_DELEN;
  856                 resid -= PFS_DELEN;
  857         }
  858         if (proc != NULL)
  859                 PROC_UNLOCK(proc);
  860         pfs_unlock(pd);
  861         sx_sunlock(&allproc_lock);
  862         i = 0;
  863         STAILQ_FOREACH_SAFE(pfsent, &lst, link, pfsent2) {
  864                 if (error == 0)
  865                         error = uiomove(&pfsent->entry, PFS_DELEN, uio);
  866                 free(pfsent, M_IOV);
  867                 i++;
  868         }
  869         PFS_TRACE(("%d bytes", i * PFS_DELEN));
  870         PFS_RETURN (error);
  871 }
  872 
  873 /*
  874  * Read a symbolic link
  875  */
  876 static int
  877 pfs_readlink(struct vop_readlink_args *va)
  878 {
  879         struct vnode *vn = va->a_vp;
  880         struct pfs_vdata *pvd = vn->v_data;
  881         struct pfs_node *pn = pvd->pvd_pn;
  882         struct uio *uio = va->a_uio;
  883         struct proc *proc = NULL;
  884         char buf[PATH_MAX];
  885         struct sbuf sb;
  886         int error, locked;
  887 
  888         PFS_TRACE(("%s", pn->pn_name));
  889         pfs_assert_not_owned(pn);
  890 
  891         if (vn->v_type != VLNK)
  892                 PFS_RETURN (EINVAL);
  893         KASSERT_PN_IS_LINK(pn);
  894 
  895         if (pn->pn_fill == NULL)
  896                 PFS_RETURN (EIO);
  897 
  898         if (pvd->pvd_pid != NO_PID) {
  899                 if ((proc = pfind(pvd->pvd_pid)) == NULL)
  900                         PFS_RETURN (EIO);
  901                 if (proc->p_flag & P_WEXIT) {
  902                         PROC_UNLOCK(proc);
  903                         PFS_RETURN (EIO);
  904                 }
  905                 _PHOLD(proc);
  906                 PROC_UNLOCK(proc);
  907         }
  908         vhold(vn);
  909         locked = VOP_ISLOCKED(vn);
  910         VOP_UNLOCK(vn, 0);
  911 
  912         /* sbuf_new() can't fail with a static buffer */
  913         sbuf_new(&sb, buf, sizeof buf, 0);
  914 
  915         error = pn_fill(curthread, proc, pn, &sb, NULL);
  916 
  917         if (proc != NULL)
  918                 PRELE(proc);
  919         vn_lock(vn, locked | LK_RETRY);
  920         vdrop(vn);
  921 
  922         if (error) {
  923                 sbuf_delete(&sb);
  924                 PFS_RETURN (error);
  925         }
  926 
  927         if (sbuf_finish(&sb) != 0) {
  928                 sbuf_delete(&sb);
  929                 PFS_RETURN (ENAMETOOLONG);
  930         }
  931 
  932         error = uiomove_frombuf(sbuf_data(&sb), sbuf_len(&sb), uio);
  933         sbuf_delete(&sb);
  934         PFS_RETURN (error);
  935 }
  936 
  937 /*
  938  * Reclaim a vnode
  939  */
  940 static int
  941 pfs_reclaim(struct vop_reclaim_args *va)
  942 {
  943         struct vnode *vn = va->a_vp;
  944         struct pfs_vdata *pvd = vn->v_data;
  945         struct pfs_node *pn = pvd->pvd_pn;
  946 
  947         PFS_TRACE(("%s", pn->pn_name));
  948         pfs_assert_not_owned(pn);
  949 
  950         return (pfs_vncache_free(va->a_vp));
  951 }
  952 
  953 /*
  954  * Set attributes
  955  */
  956 static int
  957 pfs_setattr(struct vop_setattr_args *va)
  958 {
  959         struct vnode *vn = va->a_vp;
  960         struct pfs_vdata *pvd = vn->v_data;
  961         struct pfs_node *pn = pvd->pvd_pn;
  962 
  963         PFS_TRACE(("%s", pn->pn_name));
  964         pfs_assert_not_owned(pn);
  965 
  966         PFS_RETURN (EOPNOTSUPP);
  967 }
  968 
  969 /*
  970  * Write to a file
  971  */
  972 static int
  973 pfs_write(struct vop_write_args *va)
  974 {
  975         struct vnode *vn = va->a_vp;
  976         struct pfs_vdata *pvd = vn->v_data;
  977         struct pfs_node *pn = pvd->pvd_pn;
  978         struct uio *uio = va->a_uio;
  979         struct proc *proc;
  980         struct sbuf sb;
  981         int error;
  982 
  983         PFS_TRACE(("%s", pn->pn_name));
  984         pfs_assert_not_owned(pn);
  985 
  986         if (vn->v_type != VREG)
  987                 PFS_RETURN (EINVAL);
  988         KASSERT_PN_IS_FILE(pn);
  989 
  990         if (!(pn->pn_flags & PFS_WR))
  991                 PFS_RETURN (EBADF);
  992 
  993         if (pn->pn_fill == NULL)
  994                 PFS_RETURN (EIO);
  995 
  996         /*
  997          * This is necessary because either process' privileges may
  998          * have changed since the open() call.
  999          */
 1000         if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
 1001                 PFS_RETURN (EIO);
 1002         if (proc != NULL) {
 1003                 _PHOLD(proc);
 1004                 PROC_UNLOCK(proc);
 1005         }
 1006 
 1007         if (pn->pn_flags & PFS_RAWWR) {
 1008                 error = pn_fill(curthread, proc, pn, NULL, uio);
 1009                 if (proc != NULL)
 1010                         PRELE(proc);
 1011                 PFS_RETURN (error);
 1012         }
 1013 
 1014         sbuf_uionew(&sb, uio, &error);
 1015         if (error) {
 1016                 if (proc != NULL)
 1017                         PRELE(proc);
 1018                 PFS_RETURN (error);
 1019         }
 1020 
 1021         error = pn_fill(curthread, proc, pn, &sb, uio);
 1022 
 1023         sbuf_delete(&sb);
 1024         if (proc != NULL)
 1025                 PRELE(proc);
 1026         PFS_RETURN (error);
 1027 }
 1028 
 1029 /*
 1030  * Vnode operations
 1031  */
 1032 struct vop_vector pfs_vnodeops = {
 1033         .vop_default =          &default_vnodeops,
 1034 
 1035         .vop_access =           pfs_access,
 1036         .vop_cachedlookup =     pfs_lookup,
 1037         .vop_close =            pfs_close,
 1038         .vop_create =           VOP_EOPNOTSUPP,
 1039         .vop_getattr =          pfs_getattr,
 1040         .vop_getextattr =       pfs_getextattr,
 1041         .vop_ioctl =            pfs_ioctl,
 1042         .vop_link =             VOP_EOPNOTSUPP,
 1043         .vop_lookup =           vfs_cache_lookup,
 1044         .vop_mkdir =            VOP_EOPNOTSUPP,
 1045         .vop_mknod =            VOP_EOPNOTSUPP,
 1046         .vop_open =             pfs_open,
 1047         .vop_read =             pfs_read,
 1048         .vop_readdir =          pfs_readdir,
 1049         .vop_readlink =         pfs_readlink,
 1050         .vop_reclaim =          pfs_reclaim,
 1051         .vop_remove =           VOP_EOPNOTSUPP,
 1052         .vop_rename =           VOP_EOPNOTSUPP,
 1053         .vop_rmdir =            VOP_EOPNOTSUPP,
 1054         .vop_setattr =          pfs_setattr,
 1055         .vop_symlink =          VOP_EOPNOTSUPP,
 1056         .vop_vptocnp =          pfs_vptocnp,
 1057         .vop_write =            pfs_write,
 1058         /* XXX I've probably forgotten a few that need VOP_EOPNOTSUPP */
 1059 };

Cache object: b9b85fb2945915ea3cfa51d0f072fa22


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