1 /* $NetBSD: umap_subr.c,v 1.11 1997/09/10 13:44:28 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software donated to Berkeley by 8 * Jan-Simon Pendry. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: Id: lofs_subr.c, v 1.11 1992/05/30 10:05:43 jsp Exp 39 * @(#)umap_subr.c 8.6 (Berkeley) 1/26/94 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/time.h> 45 #include <sys/types.h> 46 #include <sys/vnode.h> 47 #include <sys/mount.h> 48 #include <sys/namei.h> 49 #include <sys/malloc.h> 50 #include <miscfs/specfs/specdev.h> 51 #include <miscfs/umapfs/umap.h> 52 53 #define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */ 54 #define NUMAPNODECACHE 16 55 56 /* 57 * Null layer cache: 58 * Each cache entry holds a reference to the target vnode 59 * along with a pointer to the alias vnode. When an 60 * entry is added the target vnode is VREF'd. When the 61 * alias is removed the target vnode is vrele'd. 62 */ 63 64 #define UMAP_NHASH(vp) \ 65 (&umap_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & umap_node_hash]) 66 LIST_HEAD(umap_node_hashhead, umap_node) *umap_node_hashtbl; 67 u_long umap_node_hash; 68 69 static u_long umap_findid __P((u_long, u_long [][2], int)); 70 static struct vnode *umap_node_find __P((struct mount *, struct vnode *)); 71 static int umap_node_alloc __P((struct mount *, struct vnode *, 72 struct vnode **)); 73 74 /* 75 * Initialise cache headers 76 */ 77 void 78 umapfs_init() 79 { 80 81 #ifdef UMAPFS_DIAGNOSTIC 82 printf("umapfs_init\n"); /* printed during system boot */ 83 #endif 84 umap_node_hashtbl = hashinit(NUMAPNODECACHE, M_CACHE, &umap_node_hash); 85 } 86 87 /* 88 * umap_findid is called by various routines in umap_vnodeops.c to 89 * find a user or group id in a map. 90 */ 91 static u_long 92 umap_findid(id, map, nentries) 93 u_long id; 94 u_long map[][2]; 95 int nentries; 96 { 97 int i; 98 99 /* Find uid entry in map */ 100 i = 0; 101 while ((i<nentries) && ((map[i][0]) != id)) 102 i++; 103 104 if (i < nentries) 105 return (map[i][1]); 106 else 107 return (-1); 108 109 } 110 111 /* 112 * umap_reverse_findid is called by umap_getattr() in umap_vnodeops.c to 113 * find a user or group id in a map, in reverse. 114 */ 115 u_long 116 umap_reverse_findid(id, map, nentries) 117 u_long id; 118 u_long map[][2]; 119 int nentries; 120 { 121 int i; 122 123 /* Find uid entry in map */ 124 i = 0; 125 while ((i<nentries) && ((map[i][1]) != id)) 126 i++; 127 128 if (i < nentries) 129 return (map[i][0]); 130 else 131 return (-1); 132 133 } 134 135 /* 136 * Return alias for target vnode if already exists, else 0. 137 */ 138 static struct vnode * 139 umap_node_find(mp, targetvp) 140 struct mount *mp; 141 struct vnode *targetvp; 142 { 143 struct umap_node_hashhead *hd; 144 struct umap_node *a; 145 struct vnode *vp; 146 147 #ifdef UMAPFS_DIAGNOSTIC 148 printf("umap_node_find(mp = %p, target = %p)\n", mp, targetvp); 149 #endif 150 151 /* 152 * Find hash base, and then search the (two-way) linked 153 * list looking for a umap_node structure which is referencing 154 * the target vnode. If found, the increment the umap_node 155 * reference count (but NOT the target vnode's VREF counter). 156 */ 157 hd = UMAP_NHASH(targetvp); 158 loop: 159 for (a = hd->lh_first; a != 0; a = a->umap_hash.le_next) { 160 if (a->umap_lowervp == targetvp && 161 a->umap_vnode->v_mount == mp) { 162 vp = UMAPTOV(a); 163 /* 164 * We need vget for the VXLOCK 165 * stuff, but we don't want to lock 166 * the lower node. 167 */ 168 if (vget(vp, 0)) { 169 #ifdef UMAPFS_DIAGNOSTIC 170 printf ("umap_node_find: vget failed.\n"); 171 #endif 172 goto loop; 173 } 174 return (vp); 175 } 176 } 177 178 #ifdef UMAPFS_DIAGNOSTIC 179 printf("umap_node_find(%p, %p): NOT found\n", mp, targetvp); 180 #endif 181 182 return (0); 183 } 184 185 /* 186 * Make a new umap_node node. 187 * Vp is the alias vnode, lowervp is the target vnode. 188 * Maintain a reference to lowervp. 189 */ 190 static int 191 umap_node_alloc(mp, lowervp, vpp) 192 struct mount *mp; 193 struct vnode *lowervp; 194 struct vnode **vpp; 195 { 196 struct umap_node_hashhead *hd; 197 struct umap_node *xp; 198 struct vnode *vp, *nvp; 199 int error; 200 extern int (**dead_vnodeop_p) __P((void *)); 201 202 if ((error = getnewvnode(VT_UMAP, mp, umap_vnodeop_p, &vp)) != 0) 203 return (error); 204 vp->v_type = lowervp->v_type; 205 206 MALLOC(xp, struct umap_node *, sizeof(struct umap_node), M_TEMP, 207 M_WAITOK); 208 if (vp->v_type == VBLK || vp->v_type == VCHR) { 209 MALLOC(vp->v_specinfo, struct specinfo *, 210 sizeof(struct specinfo), M_VNODE, M_WAITOK); 211 vp->v_rdev = lowervp->v_rdev; 212 } 213 214 vp->v_data = xp; 215 xp->umap_vnode = vp; 216 xp->umap_lowervp = lowervp; 217 /* 218 * Before we insert our new node onto the hash chains, 219 * check to see if someone else has beaten us to it. 220 * (We could have slept in MALLOC.) 221 */ 222 if ((nvp = umap_node_find(mp, lowervp)) != NULL) { 223 *vpp = nvp; 224 225 /* free the substructures we've allocated. */ 226 FREE(xp, M_TEMP); 227 if (vp->v_type == VBLK || vp->v_type == VCHR) 228 FREE(vp->v_specinfo, M_VNODE); 229 230 vp->v_type = VBAD; /* node is discarded */ 231 vp->v_op = dead_vnodeop_p; /* so ops will still work */ 232 vrele(vp); /* get rid of it. */ 233 return (0); 234 } 235 236 /* 237 * XXX if it's a device node, it needs to be checkalias()ed. 238 * however, for locking reasons, that's just not possible. 239 * so we have to do most of the dirty work inline. Note that 240 * this is a limited case; we know that there's going to be 241 * an alias, and we know that that alias will be a "real" 242 * device node, i.e. not tagged VT_NON. 243 */ 244 if (vp->v_type == VBLK || vp->v_type == VCHR) { 245 struct vnode *cvp, **cvpp; 246 247 cvpp = &speclisth[SPECHASH(vp->v_rdev)]; 248 loop: 249 for (cvp = *cvpp; cvp; cvp = cvp->v_specnext) { 250 if (vp->v_rdev != cvp->v_rdev || 251 vp->v_type != cvp->v_type) 252 continue; 253 254 /* 255 * Alias, but not in use, so flush it out. 256 */ 257 if (cvp->v_usecount == 0) { 258 vgone(cvp); 259 goto loop; 260 } 261 if (vget(cvp, 0)) /* can't lock; will die! */ 262 goto loop; 263 break; 264 } 265 266 vp->v_hashchain = cvpp; 267 vp->v_specnext = *cvpp; 268 vp->v_specflags = 0; 269 *cvpp = vp; 270 #ifdef DIAGNOSTIC 271 if (cvp == NULLVP) 272 panic("umap_node_alloc: no alias for device"); 273 #endif 274 vp->v_flag |= VALIASED; 275 cvp->v_flag |= VALIASED; 276 vrele(cvp); 277 } 278 /* XXX end of transmogrified checkalias() */ 279 280 *vpp = vp; 281 VREF(lowervp); /* Extra VREF will be vrele'd in umap_node_create */ 282 hd = UMAP_NHASH(lowervp); 283 LIST_INSERT_HEAD(hd, xp, umap_hash); 284 return (0); 285 } 286 287 288 /* 289 * Try to find an existing umap_node vnode refering 290 * to it, otherwise make a new umap_node vnode which 291 * contains a reference to the target vnode. 292 */ 293 int 294 umap_node_create(mp, targetvp, newvpp) 295 struct mount *mp; 296 struct vnode *targetvp; 297 struct vnode **newvpp; 298 { 299 struct vnode *aliasvp; 300 301 if ((aliasvp = umap_node_find(mp, targetvp)) != NULL) { 302 /* 303 * Take another reference to the alias vnode 304 */ 305 #ifdef UMAPFS_DIAGNOSTIC 306 vprint("umap_node_create: exists", aliasvp); 307 #endif 308 /* VREF(aliasvp); */ 309 } else { 310 int error; 311 312 /* 313 * Get new vnode. 314 */ 315 #ifdef UMAPFS_DIAGNOSTIC 316 printf("umap_node_create: create new alias vnode\n"); 317 #endif 318 /* 319 * Make new vnode reference the umap_node. 320 */ 321 if ((error = umap_node_alloc(mp, targetvp, &aliasvp)) != 0) 322 return (error); 323 324 /* 325 * aliasvp is already VREF'd by getnewvnode() 326 */ 327 } 328 329 vrele(targetvp); 330 331 #ifdef UMAPFS_DIAGNOSTIC 332 vprint("umap_node_create: alias", aliasvp); 333 vprint("umap_node_create: target", targetvp); 334 #endif 335 336 *newvpp = aliasvp; 337 return (0); 338 } 339 340 #ifdef UMAPFS_DIAGNOSTIC 341 int umap_checkvp_barrier = 1; 342 struct vnode * 343 umap_checkvp(vp, fil, lno) 344 struct vnode *vp; 345 char *fil; 346 int lno; 347 { 348 struct umap_node *a = VTOUMAP(vp); 349 #if 0 350 /* 351 * Can't do this check because vop_reclaim runs 352 * with funny vop vector. 353 */ 354 if (vp->v_op != umap_vnodeop_p) { 355 printf("umap_checkvp: on non-umap-node\n"); 356 while (umap_checkvp_barrier) /*WAIT*/ ; 357 panic("umap_checkvp"); 358 } 359 #endif 360 if (a->umap_lowervp == NULL) { 361 /* Should never happen */ 362 int i; u_long *p; 363 printf("vp = %p, ZERO ptr\n", vp); 364 for (p = (u_long *) a, i = 0; i < 8; i++) 365 printf(" %lx", p[i]); 366 printf("\n"); 367 /* wait for debugger */ 368 while (umap_checkvp_barrier) /*WAIT*/ ; 369 panic("umap_checkvp"); 370 } 371 if (a->umap_lowervp->v_usecount < 1) { 372 int i; u_long *p; 373 printf("vp = %p, unref'ed lowervp\n", vp); 374 for (p = (u_long *) a, i = 0; i < 8; i++) 375 printf(" %lx", p[i]); 376 printf("\n"); 377 /* wait for debugger */ 378 while (umap_checkvp_barrier) /*WAIT*/ ; 379 panic ("umap with unref'ed lowervp"); 380 } 381 #if 0 382 printf("umap %p/%d -> %p/%d [%s, %d]\n", 383 a->umap_vnode, a->umap_vnode->v_usecount, 384 a->umap_lowervp, a->umap_lowervp->v_usecount, 385 fil, lno); 386 #endif 387 return (a->umap_lowervp); 388 } 389 #endif 390 391 /* umap_mapids maps all of the ids in a credential, both user and group. */ 392 393 void 394 umap_mapids(v_mount, credp) 395 struct mount *v_mount; 396 struct ucred *credp; 397 { 398 int i, unentries, gnentries; 399 uid_t uid; 400 gid_t gid; 401 u_long (*usermap)[2], (*groupmap)[2]; 402 403 if (credp == NOCRED) 404 return; 405 406 unentries = MOUNTTOUMAPMOUNT(v_mount)->info_nentries; 407 usermap = MOUNTTOUMAPMOUNT(v_mount)->info_mapdata; 408 gnentries = MOUNTTOUMAPMOUNT(v_mount)->info_gnentries; 409 groupmap = MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata; 410 411 /* Find uid entry in map */ 412 413 uid = (uid_t) umap_findid(credp->cr_uid, usermap, unentries); 414 415 if (uid != -1) 416 credp->cr_uid = uid; 417 else 418 credp->cr_uid = (uid_t) NOBODY; 419 420 #if 1 421 /* cr_gid is the same as cr_groups[0] in 4BSD, but not in NetBSD */ 422 423 /* Find gid entry in map */ 424 425 gid = (gid_t) umap_findid(credp->cr_gid, groupmap, gnentries); 426 427 if (gid != -1) 428 credp->cr_gid = gid; 429 else 430 credp->cr_gid = NULLGROUP; 431 #endif 432 433 /* Now we must map each of the set of groups in the cr_groups 434 structure. */ 435 436 i = 0; 437 while (credp->cr_groups[i] != 0) { 438 gid = (gid_t) umap_findid(credp->cr_groups[i], 439 groupmap, gnentries); 440 441 if (gid != -1) 442 credp->cr_groups[i++] = gid; 443 else 444 credp->cr_groups[i++] = NULLGROUP; 445 } 446 } 447