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("$FreeBSD$");
   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         /*
  450          * Don't support DELETE or RENAME.  CREATE is supported so
  451          * that O_CREAT will work, but the lookup will still fail if
  452          * the file does not exist.
  453          */
  454         if ((cnp->cn_flags & ISLASTCN) &&
  455             (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
  456                 PFS_RETURN (EOPNOTSUPP);
  457 
  458         /* shortcut: check if the name is too long */
  459         if (cnp->cn_namelen >= PFS_NAMELEN)
  460                 PFS_RETURN (ENOENT);
  461 
  462         /* check that parent directory is visible... */
  463         if (!pfs_visible(curthread, pd, pvd->pvd_pid, false, NULL))
  464                 PFS_RETURN (ENOENT);
  465 
  466         /* self */
  467         namelen = cnp->cn_namelen;
  468         pname = cnp->cn_nameptr;
  469         if (namelen == 1 && pname[0] == '.') {
  470                 pn = pd;
  471                 *vpp = vn;
  472                 VREF(vn);
  473                 PFS_RETURN (0);
  474         }
  475 
  476         mp = vn->v_mount;
  477 
  478         /* parent */
  479         if (cnp->cn_flags & ISDOTDOT) {
  480                 if (pd->pn_type == pfstype_root)
  481                         PFS_RETURN (EIO);
  482                 error = vfs_busy(mp, MBF_NOWAIT);
  483                 if (error != 0) {
  484                         vfs_ref(mp);
  485                         VOP_UNLOCK(vn, 0);
  486                         error = vfs_busy(mp, 0);
  487                         vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
  488                         vfs_rel(mp);
  489                         if (error != 0)
  490                                 PFS_RETURN(ENOENT);
  491                         if (vn->v_iflag & VI_DOOMED) {
  492                                 vfs_unbusy(mp);
  493                                 PFS_RETURN(ENOENT);
  494                         }
  495                 }
  496                 VOP_UNLOCK(vn, 0);
  497                 KASSERT(pd->pn_parent != NULL,
  498                     ("%s(): non-root directory has no parent", __func__));
  499                 /*
  500                  * This one is tricky.  Descendents of procdir nodes
  501                  * inherit their parent's process affinity, but
  502                  * there's no easy reverse mapping.  For simplicity,
  503                  * we assume that if this node is a procdir, its
  504                  * parent isn't (which is correct as long as
  505                  * descendents of procdir nodes are never procdir
  506                  * nodes themselves)
  507                  */
  508                 if (pd->pn_type == pfstype_procdir)
  509                         pid = NO_PID;
  510                 pfs_lock(pd);
  511                 pn = pd->pn_parent;
  512                 pfs_unlock(pd);
  513                 goto got_pnode;
  514         }
  515 
  516         pfs_lock(pd);
  517 
  518         /* named node */
  519         for (pn = pd->pn_nodes; pn != NULL; pn = pn->pn_next)
  520                 if (pn->pn_type == pfstype_procdir)
  521                         pdn = pn;
  522                 else if (pn->pn_name[namelen] == '\0' &&
  523                     bcmp(pname, pn->pn_name, namelen) == 0) {
  524                         pfs_unlock(pd);
  525                         goto got_pnode;
  526                 }
  527 
  528         /* process dependent node */
  529         if ((pn = pdn) != NULL) {
  530                 pid = 0;
  531                 for (pid = 0, i = 0; i < namelen && isdigit(pname[i]); ++i)
  532                         if ((pid = pid * 10 + pname[i] - '') > PID_MAX)
  533                                 break;
  534                 if (i == cnp->cn_namelen) {
  535                         pfs_unlock(pd);
  536                         goto got_pnode;
  537                 }
  538         }
  539 
  540         pfs_unlock(pd);
  541 
  542         PFS_RETURN (ENOENT);
  543 
  544  got_pnode:
  545         pfs_assert_not_owned(pd);
  546         pfs_assert_not_owned(pn);
  547         visible = pfs_visible(curthread, pn, pid, false, NULL);
  548         if (!visible) {
  549                 error = ENOENT;
  550                 goto failed;
  551         }
  552 
  553         error = pfs_vncache_alloc(mp, vpp, pn, pid);
  554         if (error)
  555                 goto failed;
  556 
  557         if (cnp->cn_flags & ISDOTDOT) {
  558                 vfs_unbusy(mp);
  559                 vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
  560                 if (vn->v_iflag & VI_DOOMED) {
  561                         vput(*vpp);
  562                         *vpp = NULL;
  563                         PFS_RETURN(ENOENT);
  564                 }
  565         }
  566         if (cnp->cn_flags & MAKEENTRY && !(vn->v_iflag & VI_DOOMED))
  567                 cache_enter(vn, *vpp, cnp);
  568         PFS_RETURN (0);
  569  failed:
  570         if (cnp->cn_flags & ISDOTDOT) {
  571                 vfs_unbusy(mp);
  572                 vn_lock(vn, LK_EXCLUSIVE | LK_RETRY);
  573                 *vpp = NULL;
  574         }
  575         PFS_RETURN(error);
  576 }
  577 
  578 /*
  579  * Open a file or directory.
  580  */
  581 static int
  582 pfs_open(struct vop_open_args *va)
  583 {
  584         struct vnode *vn = va->a_vp;
  585         struct pfs_vdata *pvd = vn->v_data;
  586         struct pfs_node *pn = pvd->pvd_pn;
  587         int mode = va->a_mode;
  588 
  589         PFS_TRACE(("%s (mode 0x%x)", pn->pn_name, mode));
  590         pfs_assert_not_owned(pn);
  591 
  592         /* check if the requested mode is permitted */
  593         if (((mode & FREAD) && !(mode & PFS_RD)) ||
  594             ((mode & FWRITE) && !(mode & PFS_WR)))
  595                 PFS_RETURN (EPERM);
  596 
  597         /* we don't support locking */
  598         if ((mode & O_SHLOCK) || (mode & O_EXLOCK))
  599                 PFS_RETURN (EOPNOTSUPP);
  600 
  601         PFS_RETURN (0);
  602 }
  603 
  604 /*
  605  * Read from a file
  606  */
  607 static int
  608 pfs_read(struct vop_read_args *va)
  609 {
  610         struct vnode *vn = va->a_vp;
  611         struct pfs_vdata *pvd = vn->v_data;
  612         struct pfs_node *pn = pvd->pvd_pn;
  613         struct uio *uio = va->a_uio;
  614         struct proc *proc;
  615         struct sbuf *sb = NULL;
  616         int error, locked;
  617         off_t buflen;
  618 
  619         PFS_TRACE(("%s", pn->pn_name));
  620         pfs_assert_not_owned(pn);
  621 
  622         if (vn->v_type != VREG)
  623                 PFS_RETURN (EINVAL);
  624         KASSERT_PN_IS_FILE(pn);
  625 
  626         if (!(pn->pn_flags & PFS_RD))
  627                 PFS_RETURN (EBADF);
  628 
  629         if (pn->pn_fill == NULL)
  630                 PFS_RETURN (EIO);
  631 
  632         /*
  633          * This is necessary because either process' privileges may
  634          * have changed since the open() call.
  635          */
  636         if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
  637                 PFS_RETURN (EIO);
  638         if (proc != NULL) {
  639                 _PHOLD(proc);
  640                 PROC_UNLOCK(proc);
  641         }
  642 
  643         vhold(vn);
  644         locked = VOP_ISLOCKED(vn);
  645         VOP_UNLOCK(vn, 0);
  646 
  647         if (pn->pn_flags & PFS_RAWRD) {
  648                 PFS_TRACE(("%zd resid", uio->uio_resid));
  649                 error = pn_fill(curthread, proc, pn, NULL, uio);
  650                 PFS_TRACE(("%zd resid", uio->uio_resid));
  651                 goto ret;
  652         }
  653 
  654         if (uio->uio_resid < 0 || uio->uio_offset < 0 ||
  655             uio->uio_resid > OFF_MAX - uio->uio_offset) {
  656                 error = EINVAL;
  657                 goto ret;
  658         }
  659         buflen = uio->uio_offset + uio->uio_resid;
  660         if (buflen > MAXPHYS)
  661                 buflen = MAXPHYS;
  662 
  663         sb = sbuf_new(sb, NULL, buflen + 1, 0);
  664         if (sb == NULL) {
  665                 error = EIO;
  666                 goto ret;
  667         }
  668 
  669         error = pn_fill(curthread, proc, pn, sb, uio);
  670 
  671         if (error) {
  672                 sbuf_delete(sb);
  673                 goto ret;
  674         }
  675 
  676         /*
  677          * XXX: If the buffer overflowed, sbuf_len() will not return
  678          * the data length. Then just use the full length because an
  679          * overflowed sbuf must be full.
  680          */
  681         if (sbuf_finish(sb) == 0)
  682                 buflen = sbuf_len(sb);
  683         error = uiomove_frombuf(sbuf_data(sb), buflen, uio);
  684         sbuf_delete(sb);
  685 ret:
  686         vn_lock(vn, locked | LK_RETRY);
  687         vdrop(vn);
  688         if (proc != NULL)
  689                 PRELE(proc);
  690         PFS_RETURN (error);
  691 }
  692 
  693 /*
  694  * Iterate through directory entries
  695  */
  696 static int
  697 pfs_iterate(struct thread *td, struct proc *proc, struct pfs_node *pd,
  698             struct pfs_node **pn, struct proc **p)
  699 {
  700         int visible;
  701 
  702         sx_assert(&allproc_lock, SX_SLOCKED);
  703         pfs_assert_owned(pd);
  704  again:
  705         if (*pn == NULL) {
  706                 /* first node */
  707                 *pn = pd->pn_nodes;
  708         } else if ((*pn)->pn_type != pfstype_procdir) {
  709                 /* next node */
  710                 *pn = (*pn)->pn_next;
  711         }
  712         if (*pn != NULL && (*pn)->pn_type == pfstype_procdir) {
  713                 /* next process */
  714                 if (*p == NULL)
  715                         *p = LIST_FIRST(&allproc);
  716                 else
  717                         *p = LIST_NEXT(*p, p_list);
  718                 /* out of processes: next node */
  719                 if (*p == NULL)
  720                         *pn = (*pn)->pn_next;
  721                 else
  722                         PROC_LOCK(*p);
  723         }
  724 
  725         if ((*pn) == NULL)
  726                 return (-1);
  727 
  728         if (*p != NULL) {
  729                 visible = pfs_visible_proc(td, *pn, *p);
  730                 PROC_UNLOCK(*p);
  731         } else if (proc != NULL) {
  732                 visible = pfs_visible_proc(td, *pn, proc);
  733         } else {
  734                 visible = 1;
  735         }
  736         if (!visible)
  737                 goto again;
  738 
  739         return (0);
  740 }
  741 
  742 /* Directory entry list */
  743 struct pfsentry {
  744         STAILQ_ENTRY(pfsentry)  link;
  745         struct dirent           entry;
  746 };
  747 STAILQ_HEAD(pfsdirentlist, pfsentry);
  748 
  749 /*
  750  * Return directory entries.
  751  */
  752 static int
  753 pfs_readdir(struct vop_readdir_args *va)
  754 {
  755         struct vnode *vn = va->a_vp;
  756         struct pfs_vdata *pvd = vn->v_data;
  757         struct pfs_node *pd = pvd->pvd_pn;
  758         pid_t pid = pvd->pvd_pid;
  759         struct proc *p, *proc;
  760         struct pfs_node *pn;
  761         struct uio *uio;
  762         struct pfsentry *pfsent, *pfsent2;
  763         struct pfsdirentlist lst;
  764         off_t offset;
  765         int error, i, resid;
  766 
  767         STAILQ_INIT(&lst);
  768         error = 0;
  769         KASSERT(pd->pn_info == vn->v_mount->mnt_data,
  770             ("%s(): pn_info does not match mountpoint", __func__));
  771         PFS_TRACE(("%s pid %lu", pd->pn_name, (unsigned long)pid));
  772         pfs_assert_not_owned(pd);
  773 
  774         if (vn->v_type != VDIR)
  775                 PFS_RETURN (ENOTDIR);
  776         KASSERT_PN_IS_DIR(pd);
  777         uio = va->a_uio;
  778 
  779         /* only allow reading entire entries */
  780         offset = uio->uio_offset;
  781         resid = uio->uio_resid;
  782         if (offset < 0 || offset % PFS_DELEN != 0 ||
  783             (resid && resid < PFS_DELEN))
  784                 PFS_RETURN (EINVAL);
  785         if (resid == 0)
  786                 PFS_RETURN (0);
  787 
  788         sx_slock(&allproc_lock);
  789         pfs_lock(pd);
  790 
  791         /* check if the directory is visible to the caller */
  792         if (!pfs_visible(curthread, pd, pid, true, &proc)) {
  793                 sx_sunlock(&allproc_lock);
  794                 pfs_unlock(pd);
  795                 PFS_RETURN (ENOENT);
  796         }
  797         KASSERT(pid == NO_PID || proc != NULL,
  798             ("%s(): no process for pid %lu", __func__, (unsigned long)pid));
  799 
  800         /* skip unwanted entries */
  801         for (pn = NULL, p = NULL; offset > 0; offset -= PFS_DELEN) {
  802                 if (pfs_iterate(curthread, proc, pd, &pn, &p) == -1) {
  803                         /* nothing left... */
  804                         if (proc != NULL)
  805                                 PROC_UNLOCK(proc);
  806                         pfs_unlock(pd);
  807                         sx_sunlock(&allproc_lock);
  808                         PFS_RETURN (0);
  809                 }
  810         }
  811 
  812         /* fill in entries */
  813         while (pfs_iterate(curthread, proc, pd, &pn, &p) != -1 &&
  814             resid >= PFS_DELEN) {
  815                 if ((pfsent = malloc(sizeof(struct pfsentry), M_IOV,
  816                     M_NOWAIT | M_ZERO)) == NULL) {
  817                         error = ENOMEM;
  818                         break;
  819                 }
  820                 pfsent->entry.d_reclen = PFS_DELEN;
  821                 pfsent->entry.d_fileno = pn_fileno(pn, pid);
  822                 /* PFS_DELEN was picked to fit PFS_NAMLEN */
  823                 for (i = 0; i < PFS_NAMELEN - 1 && pn->pn_name[i] != '\0'; ++i)
  824                         pfsent->entry.d_name[i] = pn->pn_name[i];
  825                 pfsent->entry.d_namlen = i;
  826                 switch (pn->pn_type) {
  827                 case pfstype_procdir:
  828                         KASSERT(p != NULL,
  829                             ("reached procdir node with p == NULL"));
  830                         pfsent->entry.d_namlen = snprintf(pfsent->entry.d_name,
  831                             PFS_NAMELEN, "%d", p->p_pid);
  832                         /* fall through */
  833                 case pfstype_root:
  834                 case pfstype_dir:
  835                 case pfstype_this:
  836                 case pfstype_parent:
  837                         pfsent->entry.d_type = DT_DIR;
  838                         break;
  839                 case pfstype_file:
  840                         pfsent->entry.d_type = DT_REG;
  841                         break;
  842                 case pfstype_symlink:
  843                         pfsent->entry.d_type = DT_LNK;
  844                         break;
  845                 default:
  846                         panic("%s has unexpected node type: %d", pn->pn_name, pn->pn_type);
  847                 }
  848                 PFS_TRACE(("%s", pfsent->entry.d_name));
  849                 dirent_terminate(&pfsent->entry);
  850                 STAILQ_INSERT_TAIL(&lst, pfsent, link);
  851                 offset += PFS_DELEN;
  852                 resid -= PFS_DELEN;
  853         }
  854         if (proc != NULL)
  855                 PROC_UNLOCK(proc);
  856         pfs_unlock(pd);
  857         sx_sunlock(&allproc_lock);
  858         i = 0;
  859         STAILQ_FOREACH_SAFE(pfsent, &lst, link, pfsent2) {
  860                 if (error == 0)
  861                         error = uiomove(&pfsent->entry, PFS_DELEN, uio);
  862                 free(pfsent, M_IOV);
  863                 i++;
  864         }
  865         PFS_TRACE(("%d bytes", i * PFS_DELEN));
  866         PFS_RETURN (error);
  867 }
  868 
  869 /*
  870  * Read a symbolic link
  871  */
  872 static int
  873 pfs_readlink(struct vop_readlink_args *va)
  874 {
  875         struct vnode *vn = va->a_vp;
  876         struct pfs_vdata *pvd = vn->v_data;
  877         struct pfs_node *pn = pvd->pvd_pn;
  878         struct uio *uio = va->a_uio;
  879         struct proc *proc = NULL;
  880         char buf[PATH_MAX];
  881         struct sbuf sb;
  882         int error, locked;
  883 
  884         PFS_TRACE(("%s", pn->pn_name));
  885         pfs_assert_not_owned(pn);
  886 
  887         if (vn->v_type != VLNK)
  888                 PFS_RETURN (EINVAL);
  889         KASSERT_PN_IS_LINK(pn);
  890 
  891         if (pn->pn_fill == NULL)
  892                 PFS_RETURN (EIO);
  893 
  894         if (pvd->pvd_pid != NO_PID) {
  895                 if ((proc = pfind(pvd->pvd_pid)) == NULL)
  896                         PFS_RETURN (EIO);
  897                 if (proc->p_flag & P_WEXIT) {
  898                         PROC_UNLOCK(proc);
  899                         PFS_RETURN (EIO);
  900                 }
  901                 _PHOLD(proc);
  902                 PROC_UNLOCK(proc);
  903         }
  904         vhold(vn);
  905         locked = VOP_ISLOCKED(vn);
  906         VOP_UNLOCK(vn, 0);
  907 
  908         /* sbuf_new() can't fail with a static buffer */
  909         sbuf_new(&sb, buf, sizeof buf, 0);
  910 
  911         error = pn_fill(curthread, proc, pn, &sb, NULL);
  912 
  913         if (proc != NULL)
  914                 PRELE(proc);
  915         vn_lock(vn, locked | LK_RETRY);
  916         vdrop(vn);
  917 
  918         if (error) {
  919                 sbuf_delete(&sb);
  920                 PFS_RETURN (error);
  921         }
  922 
  923         if (sbuf_finish(&sb) != 0) {
  924                 sbuf_delete(&sb);
  925                 PFS_RETURN (ENAMETOOLONG);
  926         }
  927 
  928         error = uiomove_frombuf(sbuf_data(&sb), sbuf_len(&sb), uio);
  929         sbuf_delete(&sb);
  930         PFS_RETURN (error);
  931 }
  932 
  933 /*
  934  * Reclaim a vnode
  935  */
  936 static int
  937 pfs_reclaim(struct vop_reclaim_args *va)
  938 {
  939         struct vnode *vn = va->a_vp;
  940         struct pfs_vdata *pvd = vn->v_data;
  941         struct pfs_node *pn = pvd->pvd_pn;
  942 
  943         PFS_TRACE(("%s", pn->pn_name));
  944         pfs_assert_not_owned(pn);
  945 
  946         return (pfs_vncache_free(va->a_vp));
  947 }
  948 
  949 /*
  950  * Set attributes
  951  */
  952 static int
  953 pfs_setattr(struct vop_setattr_args *va)
  954 {
  955         struct vnode *vn = va->a_vp;
  956         struct pfs_vdata *pvd = vn->v_data;
  957         struct pfs_node *pn = pvd->pvd_pn;
  958 
  959         PFS_TRACE(("%s", pn->pn_name));
  960         pfs_assert_not_owned(pn);
  961 
  962         PFS_RETURN (EOPNOTSUPP);
  963 }
  964 
  965 /*
  966  * Write to a file
  967  */
  968 static int
  969 pfs_write(struct vop_write_args *va)
  970 {
  971         struct vnode *vn = va->a_vp;
  972         struct pfs_vdata *pvd = vn->v_data;
  973         struct pfs_node *pn = pvd->pvd_pn;
  974         struct uio *uio = va->a_uio;
  975         struct proc *proc;
  976         struct sbuf sb;
  977         int error;
  978 
  979         PFS_TRACE(("%s", pn->pn_name));
  980         pfs_assert_not_owned(pn);
  981 
  982         if (vn->v_type != VREG)
  983                 PFS_RETURN (EINVAL);
  984         KASSERT_PN_IS_FILE(pn);
  985 
  986         if (!(pn->pn_flags & PFS_WR))
  987                 PFS_RETURN (EBADF);
  988 
  989         if (pn->pn_fill == NULL)
  990                 PFS_RETURN (EIO);
  991 
  992         /*
  993          * This is necessary because either process' privileges may
  994          * have changed since the open() call.
  995          */
  996         if (!pfs_visible(curthread, pn, pvd->pvd_pid, false, &proc))
  997                 PFS_RETURN (EIO);
  998         if (proc != NULL) {
  999                 _PHOLD(proc);
 1000                 PROC_UNLOCK(proc);
 1001         }
 1002 
 1003         if (pn->pn_flags & PFS_RAWWR) {
 1004                 error = pn_fill(curthread, proc, pn, NULL, uio);
 1005                 if (proc != NULL)
 1006                         PRELE(proc);
 1007                 PFS_RETURN (error);
 1008         }
 1009 
 1010         sbuf_uionew(&sb, uio, &error);
 1011         if (error) {
 1012                 if (proc != NULL)
 1013                         PRELE(proc);
 1014                 PFS_RETURN (error);
 1015         }
 1016 
 1017         error = pn_fill(curthread, proc, pn, &sb, uio);
 1018 
 1019         sbuf_delete(&sb);
 1020         if (proc != NULL)
 1021                 PRELE(proc);
 1022         PFS_RETURN (error);
 1023 }
 1024 
 1025 /*
 1026  * Vnode operations
 1027  */
 1028 struct vop_vector pfs_vnodeops = {
 1029         .vop_default =          &default_vnodeops,
 1030 
 1031         .vop_access =           pfs_access,
 1032         .vop_cachedlookup =     pfs_lookup,
 1033         .vop_close =            pfs_close,
 1034         .vop_create =           VOP_EOPNOTSUPP,
 1035         .vop_getattr =          pfs_getattr,
 1036         .vop_getextattr =       pfs_getextattr,
 1037         .vop_ioctl =            pfs_ioctl,
 1038         .vop_link =             VOP_EOPNOTSUPP,
 1039         .vop_lookup =           vfs_cache_lookup,
 1040         .vop_mkdir =            VOP_EOPNOTSUPP,
 1041         .vop_mknod =            VOP_EOPNOTSUPP,
 1042         .vop_open =             pfs_open,
 1043         .vop_read =             pfs_read,
 1044         .vop_readdir =          pfs_readdir,
 1045         .vop_readlink =         pfs_readlink,
 1046         .vop_reclaim =          pfs_reclaim,
 1047         .vop_remove =           VOP_EOPNOTSUPP,
 1048         .vop_rename =           VOP_EOPNOTSUPP,
 1049         .vop_rmdir =            VOP_EOPNOTSUPP,
 1050         .vop_setattr =          pfs_setattr,
 1051         .vop_symlink =          VOP_EOPNOTSUPP,
 1052         .vop_vptocnp =          pfs_vptocnp,
 1053         .vop_write =            pfs_write,
 1054         /* XXX I've probably forgotten a few that need VOP_EOPNOTSUPP */
 1055 };

Cache object: 06075b79f074c1346981cece1c5ee0c7


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