447 lines
11 KiB
C
447 lines
11 KiB
C
/* $NetBSD: umap_subr.c,v 1.8 1996/03/05 02:35:39 thorpej Exp $ */
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/*
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software donated to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: Id: lofs_subr.c, v 1.11 1992/05/30 10:05:43 jsp Exp
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* @(#)umap_subr.c 8.6 (Berkeley) 1/26/94
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/vnode.h>
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#include <sys/mount.h>
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#include <sys/namei.h>
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#include <sys/malloc.h>
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#include <miscfs/specfs/specdev.h>
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#include <miscfs/umapfs/umap.h>
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#define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */
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#define NUMAPNODECACHE 16
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/*
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* Null layer cache:
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* Each cache entry holds a reference to the target vnode
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* along with a pointer to the alias vnode. When an
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* entry is added the target vnode is VREF'd. When the
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* alias is removed the target vnode is vrele'd.
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*/
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#define UMAP_NHASH(vp) \
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(&umap_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & umap_node_hash])
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LIST_HEAD(umap_node_hashhead, umap_node) *umap_node_hashtbl;
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u_long umap_node_hash;
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static u_long umap_findid __P((u_long, u_long [][2], int));
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static struct vnode *umap_node_find __P((struct mount *, struct vnode *));
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static int umap_node_alloc __P((struct mount *, struct vnode *,
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struct vnode **));
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/*
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* Initialise cache headers
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*/
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void
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umapfs_init()
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{
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#ifdef UMAPFS_DIAGNOSTIC
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printf("umapfs_init\n"); /* printed during system boot */
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#endif
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umap_node_hashtbl = hashinit(NUMAPNODECACHE, M_CACHE, &umap_node_hash);
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}
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/*
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* umap_findid is called by various routines in umap_vnodeops.c to
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* find a user or group id in a map.
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*/
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static u_long
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umap_findid(id, map, nentries)
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u_long id;
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u_long map[][2];
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int nentries;
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{
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int i;
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/* Find uid entry in map */
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i = 0;
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while ((i<nentries) && ((map[i][0]) != id))
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i++;
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if (i < nentries)
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return (map[i][1]);
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else
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return (-1);
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}
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/*
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* umap_reverse_findid is called by umap_getattr() in umap_vnodeops.c to
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* find a user or group id in a map, in reverse.
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*/
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u_long
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umap_reverse_findid(id, map, nentries)
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u_long id;
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u_long map[][2];
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int nentries;
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{
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int i;
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/* Find uid entry in map */
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i = 0;
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while ((i<nentries) && ((map[i][1]) != id))
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i++;
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if (i < nentries)
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return (map[i][0]);
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else
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return (-1);
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}
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/*
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* Return alias for target vnode if already exists, else 0.
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*/
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static struct vnode *
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umap_node_find(mp, targetvp)
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struct mount *mp;
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struct vnode *targetvp;
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{
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struct umap_node_hashhead *hd;
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struct umap_node *a;
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struct vnode *vp;
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#ifdef UMAPFS_DIAGNOSTIC
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printf("umap_node_find(mp = %x, target = %x)\n", mp, targetvp);
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#endif
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/*
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* Find hash base, and then search the (two-way) linked
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* list looking for a umap_node structure which is referencing
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* the target vnode. If found, the increment the umap_node
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* reference count (but NOT the target vnode's VREF counter).
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*/
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hd = UMAP_NHASH(targetvp);
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loop:
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for (a = hd->lh_first; a != 0; a = a->umap_hash.le_next) {
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if (a->umap_lowervp == targetvp &&
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a->umap_vnode->v_mount == mp) {
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vp = UMAPTOV(a);
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/*
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* We need vget for the VXLOCK
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* stuff, but we don't want to lock
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* the lower node.
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*/
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if (vget(vp, 0)) {
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#ifdef UMAPFS_DIAGNOSTIC
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printf ("umap_node_find: vget failed.\n");
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#endif
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goto loop;
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}
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return (vp);
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}
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}
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#ifdef UMAPFS_DIAGNOSTIC
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printf("umap_node_find(%x, %x): NOT found\n", mp, targetvp);
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#endif
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return (0);
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}
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/*
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* Make a new umap_node node.
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* Vp is the alias vnode, lowervp is the target vnode.
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* Maintain a reference to lowervp.
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*/
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static int
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umap_node_alloc(mp, lowervp, vpp)
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struct mount *mp;
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struct vnode *lowervp;
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struct vnode **vpp;
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{
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struct umap_node_hashhead *hd;
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struct umap_node *xp;
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struct vnode *vp, *nvp;
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int error;
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extern int (**dead_vnodeop_p) __P((void *));
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if ((error = getnewvnode(VT_UMAP, mp, umap_vnodeop_p, &vp)) != 0)
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return (error);
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vp->v_type = lowervp->v_type;
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MALLOC(xp, struct umap_node *, sizeof(struct umap_node), M_TEMP,
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M_WAITOK);
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if (vp->v_type == VBLK || vp->v_type == VCHR) {
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MALLOC(vp->v_specinfo, struct specinfo *,
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sizeof(struct specinfo), M_VNODE, M_WAITOK);
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vp->v_rdev = lowervp->v_rdev;
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}
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vp->v_data = xp;
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xp->umap_vnode = vp;
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xp->umap_lowervp = lowervp;
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/*
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* Before we insert our new node onto the hash chains,
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* check to see if someone else has beaten us to it.
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* (We could have slept in MALLOC.)
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*/
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if ((nvp = umap_node_find(mp, lowervp)) != NULL) {
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*vpp = nvp;
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/* free the substructures we've allocated. */
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FREE(xp, M_TEMP);
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if (vp->v_type == VBLK || vp->v_type == VCHR)
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FREE(vp->v_specinfo, M_VNODE);
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vp->v_type = VBAD; /* node is discarded */
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vp->v_op = dead_vnodeop_p; /* so ops will still work */
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vrele(vp); /* get rid of it. */
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return (0);
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}
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/*
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* XXX if it's a device node, it needs to be checkalias()ed.
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* however, for locking reasons, that's just not possible.
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* so we have to do most of the dirty work inline. Note that
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* this is a limited case; we know that there's going to be
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* an alias, and we know that that alias will be a "real"
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* device node, i.e. not tagged VT_NON.
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*/
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if (vp->v_type == VBLK || vp->v_type == VCHR) {
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struct vnode *cvp, **cvpp;
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cvpp = &speclisth[SPECHASH(vp->v_rdev)];
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loop:
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for (cvp = *cvpp; cvp; cvp = cvp->v_specnext) {
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if (vp->v_rdev != cvp->v_rdev ||
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vp->v_type != cvp->v_type)
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continue;
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/*
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* Alias, but not in use, so flush it out.
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*/
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if (cvp->v_usecount == 0) {
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vgone(cvp);
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goto loop;
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}
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if (vget(cvp, 0)) /* can't lock; will die! */
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goto loop;
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break;
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}
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vp->v_hashchain = cvpp;
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vp->v_specnext = *cvpp;
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vp->v_specflags = 0;
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*cvpp = vp;
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#ifdef DIAGNOSTIC
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if (cvp == NULLVP)
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panic("umap_node_alloc: no alias for device");
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#endif
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vp->v_flag |= VALIASED;
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cvp->v_flag |= VALIASED;
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vrele(cvp);
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}
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/* XXX end of transmogrified checkalias() */
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*vpp = vp;
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VREF(lowervp); /* Extra VREF will be vrele'd in umap_node_create */
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hd = UMAP_NHASH(lowervp);
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LIST_INSERT_HEAD(hd, xp, umap_hash);
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return (0);
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}
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/*
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* Try to find an existing umap_node vnode refering
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* to it, otherwise make a new umap_node vnode which
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* contains a reference to the target vnode.
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*/
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int
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umap_node_create(mp, targetvp, newvpp)
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struct mount *mp;
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struct vnode *targetvp;
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struct vnode **newvpp;
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{
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struct vnode *aliasvp;
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if ((aliasvp = umap_node_find(mp, targetvp)) != NULL) {
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/*
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* Take another reference to the alias vnode
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*/
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#ifdef UMAPFS_DIAGNOSTIC
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vprint("umap_node_create: exists", ap->umap_vnode);
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#endif
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/* VREF(aliasvp); */
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} else {
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int error;
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/*
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* Get new vnode.
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*/
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#ifdef UMAPFS_DIAGNOSTIC
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printf("umap_node_create: create new alias vnode\n");
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#endif
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/*
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* Make new vnode reference the umap_node.
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*/
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if ((error = umap_node_alloc(mp, targetvp, &aliasvp)) != 0)
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return (error);
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/*
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* aliasvp is already VREF'd by getnewvnode()
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*/
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}
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vrele(targetvp);
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#ifdef UMAPFS_DIAGNOSTIC
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vprint("umap_node_create: alias", aliasvp);
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vprint("umap_node_create: target", targetvp);
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#endif
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*newvpp = aliasvp;
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return (0);
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}
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#ifdef UMAPFS_DIAGNOSTIC
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int umap_checkvp_barrier = 1;
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struct vnode *
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umap_checkvp(vp, fil, lno)
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struct vnode *vp;
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char *fil;
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int lno;
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{
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struct umap_node *a = VTOUMAP(vp);
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#if 0
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/*
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* Can't do this check because vop_reclaim runs
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* with funny vop vector.
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*/
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if (vp->v_op != umap_vnodeop_p) {
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printf ("umap_checkvp: on non-umap-node\n");
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while (umap_checkvp_barrier) /*WAIT*/ ;
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panic("umap_checkvp");
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}
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#endif
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if (a->umap_lowervp == NULL) {
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/* Should never happen */
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int i; u_long *p;
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printf("vp = %x, ZERO ptr\n", vp);
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for (p = (u_long *) a, i = 0; i < 8; i++)
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printf(" %x", p[i]);
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printf("\n");
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/* wait for debugger */
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while (umap_checkvp_barrier) /*WAIT*/ ;
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panic("umap_checkvp");
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}
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if (a->umap_lowervp->v_usecount < 1) {
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int i; u_long *p;
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printf("vp = %x, unref'ed lowervp\n", vp);
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for (p = (u_long *) a, i = 0; i < 8; i++)
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printf(" %x", p[i]);
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printf("\n");
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/* wait for debugger */
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while (umap_checkvp_barrier) /*WAIT*/ ;
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panic ("umap with unref'ed lowervp");
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}
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#if 0
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printf("umap %x/%d -> %x/%d [%s, %d]\n",
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a->umap_vnode, a->umap_vnode->v_usecount,
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a->umap_lowervp, a->umap_lowervp->v_usecount,
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fil, lno);
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#endif
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return (a->umap_lowervp);
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}
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#endif
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/* umap_mapids maps all of the ids in a credential, both user and group. */
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void
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umap_mapids(v_mount, credp)
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struct mount *v_mount;
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struct ucred *credp;
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{
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int i, unentries, gnentries;
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uid_t uid;
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gid_t gid;
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u_long (*usermap)[2], (*groupmap)[2];
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if (credp == NOCRED)
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return;
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unentries = MOUNTTOUMAPMOUNT(v_mount)->info_nentries;
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usermap = MOUNTTOUMAPMOUNT(v_mount)->info_mapdata;
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gnentries = MOUNTTOUMAPMOUNT(v_mount)->info_gnentries;
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groupmap = MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata;
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/* Find uid entry in map */
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uid = (uid_t) umap_findid(credp->cr_uid, usermap, unentries);
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if (uid != -1)
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credp->cr_uid = uid;
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else
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credp->cr_uid = (uid_t) NOBODY;
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#if 1
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/* cr_gid is the same as cr_groups[0] in 4BSD, but not in NetBSD */
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/* Find gid entry in map */
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gid = (gid_t) umap_findid(credp->cr_gid, groupmap, gnentries);
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if (gid != -1)
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credp->cr_gid = gid;
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else
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credp->cr_gid = NULLGROUP;
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#endif
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/* Now we must map each of the set of groups in the cr_groups
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structure. */
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i = 0;
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while (credp->cr_groups[i] != 0) {
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gid = (gid_t) umap_findid(credp->cr_groups[i],
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groupmap, gnentries);
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if (gid != -1)
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credp->cr_groups[i++] = gid;
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else
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credp->cr_groups[i++] = NULLGROUP;
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}
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}
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