1 /* $NetBSD: umap_subr.c,v 1.13 1998/03/01 02:21:51 fvdl Exp $ */ 2 3 /* 4 * Copyright (c) 1992, 1993, 1995 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 8.9 (Berkeley) 5/14/95 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/proc.h> 45 #include <sys/time.h> 46 #include <sys/types.h> 47 #include <sys/vnode.h> 48 #include <sys/mount.h> 49 #include <sys/namei.h> 50 #include <sys/malloc.h> 51 #include <miscfs/specfs/specdev.h> 52 #include <miscfs/umapfs/umap.h> 53 54 #define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */ 55 #define NUMAPNODECACHE 16 56 57 /* 58 * Null layer cache: 59 * Each cache entry holds a reference to the target vnode 60 * along with a pointer to the alias vnode. When an 61 * entry is added the target vnode is VREF'd. When the 62 * alias is removed the target vnode is vrele'd. 63 */ 64 65 #define UMAP_NHASH(vp) \ 66 (&umap_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & umap_node_hash]) 67 LIST_HEAD(umap_node_hashhead, umap_node) *umap_node_hashtbl; 68 u_long umap_node_hash; 69 70 static u_long umap_findid __P((u_long, u_long [][2], int)); 71 static struct vnode *umap_node_find __P((struct mount *, struct vnode *)); 72 static int umap_node_alloc __P((struct mount *, struct vnode *, 73 struct vnode **)); 74 75 /* 76 * Initialise cache headers 77 */ 78 void 79 umapfs_init() 80 { 81 82 #ifdef UMAPFS_DIAGNOSTIC 83 printf("umapfs_init\n"); /* printed during system boot */ 84 #endif 85 umap_node_hashtbl = hashinit(NUMAPNODECACHE, M_CACHE, M_WAITOK, &umap_node_hash); 86 } 87 88 /* 89 * umap_findid is called by various routines in umap_vnodeops.c to 90 * find a user or group id in a map. 91 */ 92 static u_long 93 umap_findid(id, map, nentries) 94 u_long id; 95 u_long map[][2]; 96 int nentries; 97 { 98 int i; 99 100 /* Find uid entry in map */ 101 i = 0; 102 while ((i<nentries) && ((map[i][0]) != id)) 103 i++; 104 105 if (i < nentries) 106 return (map[i][1]); 107 else 108 return (-1); 109 110 } 111 112 /* 113 * umap_reverse_findid is called by umap_getattr() in umap_vnodeops.c to 114 * find a user or group id in a map, in reverse. 115 */ 116 u_long 117 umap_reverse_findid(id, map, nentries) 118 u_long id; 119 u_long map[][2]; 120 int nentries; 121 { 122 int i; 123 124 /* Find uid entry in map */ 125 i = 0; 126 while ((i<nentries) && ((map[i][1]) != id)) 127 i++; 128 129 if (i < nentries) 130 return (map[i][0]); 131 else 132 return (-1); 133 134 } 135 136 /* 137 * Return alias for target vnode if already exists, else 0. 138 */ 139 static struct vnode * 140 umap_node_find(mp, targetvp) 141 struct mount *mp; 142 struct vnode *targetvp; 143 { 144 struct umap_node_hashhead *hd; 145 struct umap_node *a; 146 struct vnode *vp; 147 148 #ifdef UMAPFS_DIAGNOSTIC 149 printf("umap_node_find(mp = %p, target = %p)\n", mp, targetvp); 150 #endif 151 152 /* 153 * Find hash base, and then search the (two-way) linked 154 * list looking for a umap_node structure which is referencing 155 * the target vnode. If found, the increment the umap_node 156 * reference count (but NOT the target vnode's VREF counter). 157 */ 158 hd = UMAP_NHASH(targetvp); 159 loop: 160 for (a = hd->lh_first; a != 0; a = a->umap_hash.le_next) { 161 if (a->umap_lowervp == targetvp && 162 a->umap_vnode->v_mount == mp) { 163 vp = UMAPTOV(a); 164 /* 165 * We need vget for the VXLOCK 166 * stuff, but we don't want to lock 167 * the lower node. 168 */ 169 if (vget(vp, 0)) { 170 #ifdef UMAPFS_DIAGNOSTIC 171 printf ("umap_node_find: vget failed.\n"); 172 #endif 173 goto loop; 174 } 175 return (vp); 176 } 177 } 178 179 #ifdef UMAPFS_DIAGNOSTIC 180 printf("umap_node_find(%p, %p): NOT found\n", mp, targetvp); 181 #endif 182 183 return (0); 184 } 185 186 /* 187 * Make a new umap_node node. 188 * Vp is the alias vnode, lowervp is the target vnode. 189 * Maintain a reference to lowervp. 190 */ 191 static int 192 umap_node_alloc(mp, lowervp, vpp) 193 struct mount *mp; 194 struct vnode *lowervp; 195 struct vnode **vpp; 196 { 197 struct umap_node_hashhead *hd; 198 struct umap_node *xp; 199 struct vnode *vp, *nvp; 200 struct proc *p = curproc; /* XXX */ 201 int error; 202 extern int (**dead_vnodeop_p) __P((void *)); 203 204 if ((error = getnewvnode(VT_UMAP, mp, umap_vnodeop_p, &vp)) != 0) 205 return (error); 206 vp->v_type = lowervp->v_type; 207 208 MALLOC(xp, struct umap_node *, sizeof(struct umap_node), M_TEMP, 209 M_WAITOK); 210 if (vp->v_type == VBLK || vp->v_type == VCHR) { 211 MALLOC(vp->v_specinfo, struct specinfo *, 212 sizeof(struct specinfo), M_VNODE, M_WAITOK); 213 vp->v_rdev = lowervp->v_rdev; 214 } 215 216 vp->v_data = xp; 217 xp->umap_vnode = vp; 218 xp->umap_lowervp = lowervp; 219 /* 220 * Before we insert our new node onto the hash chains, 221 * check to see if someone else has beaten us to it. 222 * (We could have slept in MALLOC.) 223 */ 224 if ((nvp = umap_node_find(mp, lowervp)) != NULL) { 225 *vpp = nvp; 226 227 /* free the substructures we've allocated. */ 228 FREE(xp, M_TEMP); 229 if (vp->v_type == VBLK || vp->v_type == VCHR) 230 FREE(vp->v_specinfo, M_VNODE); 231 232 vp->v_type = VBAD; /* node is discarded */ 233 vp->v_op = dead_vnodeop_p; /* so ops will still work */ 234 vrele(vp); /* get rid of it. */ 235 return (0); 236 } 237 238 /* 239 * XXX if it's a device node, it needs to be checkalias()ed. 240 * however, for locking reasons, that's just not possible. 241 * so we have to do most of the dirty work inline. Note that 242 * this is a limited case; we know that there's going to be 243 * an alias, and we know that that alias will be a "real" 244 * device node, i.e. not tagged VT_NON. 245 */ 246 if (vp->v_type == VBLK || vp->v_type == VCHR) { 247 struct vnode *cvp, **cvpp; 248 249 cvpp = &speclisth[SPECHASH(vp->v_rdev)]; 250 loop: 251 simple_lock(&spechash_slock); 252 for (cvp = *cvpp; cvp; cvp = cvp->v_specnext) { 253 if (vp->v_rdev != cvp->v_rdev || 254 vp->v_type != cvp->v_type) 255 continue; 256 257 /* 258 * Alias, but not in use, so flush it out. 259 */ 260 simple_lock(&cvp->v_interlock); 261 if (cvp->v_usecount == 0) { 262 simple_unlock(&spechash_slock); 263 vgonel(cvp, p); 264 goto loop; 265 } 266 if (vget(cvp, LK_EXCLUSIVE | LK_INTERLOCK)) { 267 simple_unlock(&spechash_slock); 268 goto loop; 269 } 270 break; 271 } 272 273 vp->v_hashchain = cvpp; 274 vp->v_specnext = *cvpp; 275 vp->v_specflags = 0; 276 *cvpp = vp; 277 #ifdef DIAGNOSTIC 278 if (cvp == NULLVP) 279 panic("umap_node_alloc: no alias for device"); 280 #endif 281 vp->v_flag |= VALIASED; 282 cvp->v_flag |= VALIASED; 283 simple_unlock(&spechash_slock); 284 vrele(cvp); 285 } 286 /* XXX end of transmogrified checkalias() */ 287 288 *vpp = vp; 289 VREF(lowervp); /* Extra VREF will be vrele'd in umap_node_create */ 290 hd = UMAP_NHASH(lowervp); 291 LIST_INSERT_HEAD(hd, xp, umap_hash); 292 return (0); 293 } 294 295 296 /* 297 * Try to find an existing umap_node vnode refering 298 * to it, otherwise make a new umap_node vnode which 299 * contains a reference to the target vnode. 300 */ 301 int 302 umap_node_create(mp, targetvp, newvpp) 303 struct mount *mp; 304 struct vnode *targetvp; 305 struct vnode **newvpp; 306 { 307 struct vnode *aliasvp; 308 309 if ((aliasvp = umap_node_find(mp, targetvp)) != NULL) { 310 /* 311 * Take another reference to the alias vnode 312 */ 313 #ifdef UMAPFS_DIAGNOSTIC 314 vprint("umap_node_create: exists", aliasvp); 315 #endif 316 /* VREF(aliasvp); */ 317 } else { 318 int error; 319 320 /* 321 * Get new vnode. 322 */ 323 #ifdef UMAPFS_DIAGNOSTIC 324 printf("umap_node_create: create new alias vnode\n"); 325 #endif 326 /* 327 * Make new vnode reference the umap_node. 328 */ 329 if ((error = umap_node_alloc(mp, targetvp, &aliasvp)) != 0) 330 return (error); 331 332 /* 333 * aliasvp is already VREF'd by getnewvnode() 334 */ 335 } 336 337 vrele(targetvp); 338 339 #ifdef UMAPFS_DIAGNOSTIC 340 vprint("umap_node_create: alias", aliasvp); 341 vprint("umap_node_create: target", targetvp); 342 #endif 343 344 *newvpp = aliasvp; 345 return (0); 346 } 347 348 #ifdef UMAPFS_DIAGNOSTIC 349 int umap_checkvp_barrier = 1; 350 struct vnode * 351 umap_checkvp(vp, fil, lno) 352 struct vnode *vp; 353 char *fil; 354 int lno; 355 { 356 struct umap_node *a = VTOUMAP(vp); 357 #if 0 358 /* 359 * Can't do this check because vop_reclaim runs 360 * with funny vop vector. 361 */ 362 if (vp->v_op != umap_vnodeop_p) { 363 printf("umap_checkvp: on non-umap-node\n"); 364 while (umap_checkvp_barrier) /*WAIT*/ ; 365 panic("umap_checkvp"); 366 } 367 #endif 368 if (a->umap_lowervp == NULL) { 369 /* Should never happen */ 370 int i; u_long *p; 371 printf("vp = %p, ZERO ptr\n", vp); 372 for (p = (u_long *) a, i = 0; i < 8; i++) 373 printf(" %lx", p[i]); 374 printf("\n"); 375 /* wait for debugger */ 376 while (umap_checkvp_barrier) /*WAIT*/ ; 377 panic("umap_checkvp"); 378 } 379 if (a->umap_lowervp->v_usecount < 1) { 380 int i; u_long *p; 381 printf("vp = %p, unref'ed lowervp\n", vp); 382 for (p = (u_long *) a, i = 0; i < 8; i++) 383 printf(" %lx", p[i]); 384 printf("\n"); 385 /* wait for debugger */ 386 while (umap_checkvp_barrier) /*WAIT*/ ; 387 panic ("umap with unref'ed lowervp"); 388 } 389 #if 0 390 printf("umap %p/%d -> %p/%d [%s, %d]\n", 391 a->umap_vnode, a->umap_vnode->v_usecount, 392 a->umap_lowervp, a->umap_lowervp->v_usecount, 393 fil, lno); 394 #endif 395 return (a->umap_lowervp); 396 } 397 #endif 398 399 /* umap_mapids maps all of the ids in a credential, both user and group. */ 400 401 void 402 umap_mapids(v_mount, credp) 403 struct mount *v_mount; 404 struct ucred *credp; 405 { 406 int i, unentries, gnentries; 407 uid_t uid; 408 gid_t gid; 409 u_long (*usermap)[2], (*groupmap)[2]; 410 411 if (credp == NOCRED) 412 return; 413 414 unentries = MOUNTTOUMAPMOUNT(v_mount)->info_nentries; 415 usermap = MOUNTTOUMAPMOUNT(v_mount)->info_mapdata; 416 gnentries = MOUNTTOUMAPMOUNT(v_mount)->info_gnentries; 417 groupmap = MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata; 418 419 /* Find uid entry in map */ 420 421 uid = (uid_t) umap_findid(credp->cr_uid, usermap, unentries); 422 423 if (uid != -1) 424 credp->cr_uid = uid; 425 else 426 credp->cr_uid = (uid_t) NOBODY; 427 428 #if 1 429 /* cr_gid is the same as cr_groups[0] in 4BSD, but not in NetBSD */ 430 431 /* Find gid entry in map */ 432 433 gid = (gid_t) umap_findid(credp->cr_gid, groupmap, gnentries); 434 435 if (gid != -1) 436 credp->cr_gid = gid; 437 else 438 credp->cr_gid = NULLGROUP; 439 #endif 440 441 /* Now we must map each of the set of groups in the cr_groups 442 structure. */ 443 444 i = 0; 445 while (credp->cr_groups[i] != 0) { 446 gid = (gid_t) umap_findid(credp->cr_groups[i], 447 groupmap, gnentries); 448 449 if (gid != -1) 450 credp->cr_groups[i++] = gid; 451 else 452 credp->cr_groups[i++] = NULLGROUP; 453 } 454 } 455