bsd/miscfs/umapfs/umap_subr.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*      $NetBSD: umap_subr.c,v 1.4 1994/09/20 06:43:02 cgd Exp $        */
  23
  24 /*
  25  * Copyright (c) 1992, 1993
  26  *      The Regents of the University of California.  All rights reserved.
  27  *
  28  * This code is derived from software donated to Berkeley by
  29  * Jan-Simon Pendry.
  30  *
  31  * Redistribution and use in source and binary forms, with or without
  32  * modification, are permitted provided that the following conditions
  33  * are met:
  34  * 1. Redistributions of source code must retain the above copyright
  35  *    notice, this list of conditions and the following disclaimer.
  36  * 2. Redistributions in binary form must reproduce the above copyright
  37  *    notice, this list of conditions and the following disclaimer in the
  38  *    documentation and/or other materials provided with the distribution.
  39  * 3. All advertising materials mentioning features or use of this software
  40  *    must display the following acknowledgement:
  41  *      This product includes software developed by the University of
  42  *      California, Berkeley and its contributors.
  43  * 4. Neither the name of the University nor the names of its contributors
  44  *    may be used to endorse or promote products derived from this software
  45  *    without specific prior written permission.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  57  * SUCH DAMAGE.
  58  *
  59  *      from: Id: lofs_subr.c, v 1.11 1992/05/30 10:05:43 jsp Exp
  60  *      @(#)umap_subr.c 8.6 (Berkeley) 1/26/94
  61  */
  62
  63 #include <sys/param.h>
  64 #include <sys/systm.h>
  65 #include <sys/time.h>
  66 #include <sys/types.h>
  67 #include <sys/vnode.h>
  68 #include <sys/mount.h>
  69 #include <sys/namei.h>
  70 #include <sys/malloc.h>
  71 #include <sys/ubc.h>
  72 #include <miscfs/specfs/specdev.h>
  73 #include <miscfs/umapfs/umap.h>
  74
  75 #define LOG2_SIZEVNODE 7                /* log2(sizeof struct vnode) */
  76 #define NUMAPNODECACHE 16
  77
  78 /*
  79  * Null layer cache:
  80  * Each cache entry holds a reference to the target vnode
  81  * along with a pointer to the alias vnode.  When an
  82  * entry is added the target vnode is VREF'd.  When the
  83  * alias is removed the target vnode is vrele'd.
  84  */
  85
  86 #define UMAP_NHASH(vp) \
  87         (&umap_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & umap_node_hash])
  88 LIST_HEAD(umap_node_hashhead, umap_node) *umap_node_hashtbl;
  89 u_long umap_node_hash;
  90
  91 /*
  92  * Initialise cache headers
  93  */
  94 umapfs_init()
  95 {
  96
  97 #ifdef UMAPFS_DIAGNOSTIC
  98         printf("umapfs_init\n");                /* printed during system boot */
  99 #endif
 100         umap_node_hashtbl = hashinit(NUMAPNODECACHE, M_CACHE, &umap_node_hash);
 101 }
 102
 103 /*
 104  * umap_findid is called by various routines in umap_vnodeops.c to
 105  * find a user or group id in a map.
 106  */
 107 static u_long
 108 umap_findid(id, map, nentries)
 109         u_long id;
 110         u_long map[][2];
 111         int nentries;
 112 {
 113         int i;
 114
 115         /* Find uid entry in map */
 116         i = 0;
 117         while ((i<nentries) && ((map[i][0]) != id))
 118                 i++;
 119
 120         if (i < nentries)
 121                 return (map[i][1]);
 122         else
 123                 return (-1);
 124
 125 }
 126
 127 /*
 128  * umap_reverse_findid is called by umap_getattr() in umap_vnodeops.c to
 129  * find a user or group id in a map, in reverse.
 130  */
 131 u_long
 132 umap_reverse_findid(id, map, nentries)
 133         u_long id;
 134         u_long map[][2];
 135         int nentries;
 136 {
 137         int i;
 138
 139         /* Find uid entry in map */
 140         i = 0;
 141         while ((i<nentries) && ((map[i][1]) != id))
 142                 i++;
 143
 144         if (i < nentries)
 145                 return (map[i][0]);
 146         else
 147                 return (-1);
 148
 149 }
 150
 151 /*
 152  * Return alias for target vnode if already exists, else 0.
 153  */
 154 static struct vnode *
 155 umap_node_find(mp, targetvp)
 156         struct mount *mp;
 157         struct vnode *targetvp;
 158 {
 159         struct umap_node_hashhead *hd;
 160         struct umap_node *a;
 161         struct vnode *vp;
 162
 163 #ifdef UMAPFS_DIAGNOSTIC
 164         printf("umap_node_find(mp = %x, target = %x)\n", mp, targetvp);
 165 #endif
 166
 167         /*
 168          * Find hash base, and then search the (two-way) linked
 169          * list looking for a umap_node structure which is referencing
 170          * the target vnode.  If found, the increment the umap_node
 171          * reference count (but NOT the target vnode's VREF counter).
 172          */
 173         hd = UMAP_NHASH(targetvp);
 174 loop:
 175         for (a = hd->lh_first; a != 0; a = a->umap_hash.le_next) {
 176                 if (a->umap_lowervp == targetvp &&
 177                     a->umap_vnode->v_mount == mp) {
 178                         vp = UMAPTOV(a);
 179                         /*
 180                          * We need vget for the VXLOCK
 181                          * stuff, but we don't want to lock
 182                          * the lower node.
 183                          */
 184                         if (vget(vp, 0, current_proc())) {
 185 #ifdef UMAPFS_DIAGNOSTIC
 186                                 printf ("umap_node_find: vget failed.\n");
 187 #endif
 188                                 goto loop;
 189                         }
 190                         return (vp);
 191                 }
 192         }
 193
 194 #ifdef UMAPFS_DIAGNOSTIC
 195         printf("umap_node_find(%x, %x): NOT found\n", mp, targetvp);
 196 #endif
 197
 198         return (0);
 199 }
 200
 201 /*
 202  * Make a new umap_node node.
 203  * Vp is the alias vnode, lowervp is the target vnode.
 204  * Maintain a reference to lowervp.
 205  */
 206 static int
 207 umap_node_alloc(mp, lowervp, vpp)
 208         struct mount *mp;
 209         struct vnode *lowervp;
 210         struct vnode **vpp;
 211 {
 212         struct umap_node_hashhead *hd;
 213         struct umap_node *xp;
 214         struct vnode *vp, *nvp;
 215         int error;
 216         extern int (**dead_vnodeop_p)(void *);
 217         struct specinfo *sp = (struct specinfo *)0;
 218
 219         if (lowervp->v_type == VBLK || lowervp->v_type == VCHR)
 220                 MALLOC_ZONE(sp, struct specinfo *, sizeof(struct specinfo),
 221                         M_VNODE, M_WAITOK);
 222
 223         MALLOC(xp, struct umap_node *, sizeof(struct umap_node), M_TEMP,
 224             M_WAITOK);
 225         if (error = getnewvnode(VT_UMAP, mp, umap_vnodeop_p, &vp)) {
 226                 FREE(xp, M_TEMP);
 227                 if (sp)
 228                         FREE_ZONE(sp, sizeof (struct specinfo), M_VNODE);
 229                 return (error);
 230         }
 231         vp->v_type = lowervp->v_type;
 232
 233         if (vp->v_type == VBLK || vp->v_type == VCHR) {
 234                 vp->v_specinfo = sp;
 235                 vp->v_rdev = lowervp->v_rdev;
 236         }
 237
 238         vp->v_data = xp;
 239         xp->umap_vnode = vp;
 240         xp->umap_lowervp = lowervp;
 241         /*
 242          * Before we insert our new node onto the hash chains,
 243          * check to see if someone else has beaten us to it.
 244          */
 245         if (nvp = umap_node_find(lowervp)) {
 246                 *vpp = nvp;
 247
 248                 /* free the substructures we've allocated. */
 249                 FREE(xp, M_TEMP);
 250                 if (sp) {
 251                         vp->v_specinfo = (struct specinfo *)0;
 252                         FREE_ZONE(sp, sizeof (struct specinfo), M_VNODE);
 253                 }
 254
 255                 vp->v_type = VBAD;              /* node is discarded */
 256                 vp->v_op = dead_vnodeop_p;      /* so ops will still work */
 257                 vrele(vp);                      /* get rid of it. */
 258                 return (0);
 259         }
 260
 261         /*
 262          * XXX if it's a device node, it needs to be checkalias()ed.
 263          * however, for locking reasons, that's just not possible.
 264          * so we have to do most of the dirty work inline.  Note that
 265          * this is a limited case; we know that there's going to be
 266          * an alias, and we know that that alias will be a "real"
 267          * device node, i.e. not tagged VT_NON.
 268          */
 269         if (vp->v_type == VBLK || vp->v_type == VCHR) {
 270                 struct vnode *cvp, **cvpp;
 271
 272                 cvpp = &speclisth[SPECHASH(vp->v_rdev)];
 273 loop:
 274                 for (cvp = *cvpp; cvp; cvp = cvp->v_specnext) {
 275                         if (vp->v_rdev != cvp->v_rdev ||
 276                             vp->v_type != cvp->v_type)
 277                                 continue;
 278
 279                         /*
 280                          * Alias, but not in use, so flush it out.
 281                          */
 282                         if (cvp->v_usecount == 0) {
 283                                 vgone(cvp);
 284                                 goto loop;
 285                         }
 286                         if (vget(cvp, 0, current_proc()))       /* can't lock; will die! */
 287                                 goto loop;
 288                         break;
 289                 }
 290
 291                 vp->v_hashchain = cvpp;
 292                 vp->v_specnext = *cvpp;
 293                 vp->v_specflags = 0;
 294                 *cvpp = vp;
 295 #if DIAGNOSTIC
 296                 if (cvp == NULLVP)
 297                         panic("umap_node_alloc: no alias for device");
 298 #endif
 299                 vp->v_flag |= VALIASED;
 300                 cvp->v_flag |= VALIASED;
 301                 vrele(cvp);
 302         }
 303         /* XXX end of transmogrified checkalias() */
 304
 305         if (vp->v_type == VREG)
 306                 ubc_info_init(vp);
 307
 308         *vpp = vp;
 309         VREF(lowervp);  /* Extra VREF will be vrele'd in umap_node_create */
 310         hd = UMAP_NHASH(lowervp);
 311         LIST_INSERT_HEAD(hd, xp, umap_hash);
 312         return (0);
 313 }
 314
 315
 316 /*
 317  * Try to find an existing umap_node vnode refering
 318  * to it, otherwise make a new umap_node vnode which
 319  * contains a reference to the target vnode.
 320  */
 321 int
 322 umap_node_create(mp, targetvp, newvpp)
 323         struct mount *mp;
 324         struct vnode *targetvp;
 325         struct vnode **newvpp;
 326 {
 327         struct vnode *aliasvp;
 328
 329         if (aliasvp = umap_node_find(mp, targetvp)) {
 330                 /*
 331                  * Take another reference to the alias vnode
 332                  */
 333 #ifdef UMAPFS_DIAGNOSTIC
 334                 vprint("umap_node_create: exists", ap->umap_vnode);
 335 #endif
 336                 /* VREF(aliasvp); */
 337         } else {
 338                 int error;
 339
 340                 /*
 341                  * Get new vnode.
 342                  */
 343 #ifdef UMAPFS_DIAGNOSTIC
 344                 printf("umap_node_create: create new alias vnode\n");
 345 #endif
 346                 /*
 347                  * Make new vnode reference the umap_node.
 348                  */
 349                 if (error = umap_node_alloc(mp, targetvp, &aliasvp))
 350                         return (error);
 351
 352                 /*
 353                  * aliasvp is already VREF'd by getnewvnode()
 354                  */
 355         }
 356
 357         vrele(targetvp);
 358
 359 #ifdef UMAPFS_DIAGNOSTIC
 360         vprint("umap_node_create: alias", aliasvp);
 361         vprint("umap_node_create: target", targetvp);
 362 #endif
 363
 364         *newvpp = aliasvp;
 365         return (0);
 366 }
 367
 368 #ifdef UMAPFS_DIAGNOSTIC
 369 int umap_checkvp_barrier = 1;
 370 struct vnode *
 371 umap_checkvp(vp, fil, lno)
 372         struct vnode *vp;
 373         char *fil;
 374         int lno;
 375 {
 376         struct umap_node *a = VTOUMAP(vp);
 377 #if 0
 378         /*
 379          * Can't do this check because vop_reclaim runs
 380          * with funny vop vector.
 381          */
 382         if (vp->v_op != umap_vnodeop_p) {
 383                 printf ("umap_checkvp: on non-umap-node\n");
 384                 while (umap_checkvp_barrier) /*WAIT*/ ;
 385                 panic("umap_checkvp");
 386         }
 387 #endif
 388         if (a->umap_lowervp == NULL) {
 389                 /* Should never happen */
 390                 int i; u_long *p;
 391                 printf("vp = %x, ZERO ptr\n", vp);
 392                 for (p = (u_long *) a, i = 0; i < 8; i++)
 393                         printf(" %x", p[i]);
 394                 printf("\n");
 395                 /* wait for debugger */
 396                 while (umap_checkvp_barrier) /*WAIT*/ ;
 397                 panic("umap_checkvp");
 398         }
 399         if (a->umap_lowervp->v_usecount < 1) {
 400                 int i; u_long *p;
 401                 printf("vp = %x, unref'ed lowervp\n", vp);
 402                 for (p = (u_long *) a, i = 0; i < 8; i++)
 403                         printf(" %x", p[i]);
 404                 printf("\n");
 405                 /* wait for debugger */
 406                 while (umap_checkvp_barrier) /*WAIT*/ ;
 407                 panic ("umap with unref'ed lowervp");
 408         }
 409 #if 0
 410         printf("umap %x/%d -> %x/%d [%s, %d]\n",
 411                 a->umap_vnode, a->umap_vnode->v_usecount,
 412                 a->umap_lowervp, a->umap_lowervp->v_usecount,
 413                 fil, lno);
 414 #endif
 415         return (a->umap_lowervp);
 416 }
 417 #endif
 418
 419 /* umap_mapids maps all of the ids in a credential, both user and group. */
 420
 421 void
 422 umap_mapids(v_mount, credp)
 423         struct mount *v_mount;
 424         struct ucred *credp;
 425 {
 426         int i, unentries, gnentries;
 427         uid_t uid, *usermap;
 428         gid_t gid, *groupmap;
 429
 430         unentries =  MOUNTTOUMAPMOUNT(v_mount)->info_nentries;
 431         usermap =  &(MOUNTTOUMAPMOUNT(v_mount)->info_mapdata[0][0]);
 432         gnentries =  MOUNTTOUMAPMOUNT(v_mount)->info_gnentries;
 433         groupmap =  &(MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata[0][0]);
 434
 435         /* Find uid entry in map */
 436
 437         uid = (uid_t) umap_findid(credp->cr_uid, usermap, unentries);
 438
 439         if (uid != -1)
 440                 credp->cr_uid = uid;
 441         else
 442                 credp->cr_uid = (uid_t) NOBODY;
 443
 444 #ifdef notdef
 445         /* cr_gid is the same as cr_groups[0] in 4BSD */
 446
 447         /* Find gid entry in map */
 448
 449         gid = (gid_t) umap_findid(credp->cr_gid, groupmap, gnentries);
 450
 451         if (gid != -1)
 452                 credp->cr_gid = gid;
 453         else
 454                 credp->cr_gid = NULLGROUP;
 455 #endif
 456
 457         /* Now we must map each of the set of groups in the cr_groups
 458                 structure. */
 459
 460         i = 0;
 461         while (credp->cr_groups[i] != 0) {
 462                 gid = (gid_t) umap_findid(credp->cr_groups[i],
 463                                         groupmap, gnentries);
 464
 465                 if (gid != -1)
 466                         credp->cr_groups[i++] = gid;
 467                 else
 468                         credp->cr_groups[i++] = NULLGROUP;
 469         }
 470 }