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Annotation of XNU/bsd/miscfs/umapfs/umap_subr.c, revision 1.1

1.1     ! root        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 <miscfs/specfs/specdev.h>
        !            72: #include <miscfs/umapfs/umap.h>
        !            73: 
        !            74: #define LOG2_SIZEVNODE 7               /* log2(sizeof struct vnode) */
        !            75: #define        NUMAPNODECACHE 16
        !            76: 
        !            77: /*
        !            78:  * Null layer cache:
        !            79:  * Each cache entry holds a reference to the target vnode
        !            80:  * along with a pointer to the alias vnode.  When an
        !            81:  * entry is added the target vnode is VREF'd.  When the
        !            82:  * alias is removed the target vnode is vrele'd.
        !            83:  */
        !            84: 
        !            85: #define        UMAP_NHASH(vp) \
        !            86:        (&umap_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & umap_node_hash])
        !            87: LIST_HEAD(umap_node_hashhead, umap_node) *umap_node_hashtbl;
        !            88: u_long umap_node_hash;
        !            89: 
        !            90: /*
        !            91:  * Initialise cache headers
        !            92:  */
        !            93: umapfs_init()
        !            94: {
        !            95: 
        !            96: #ifdef UMAPFS_DIAGNOSTIC
        !            97:        printf("umapfs_init\n");                /* printed during system boot */
        !            98: #endif
        !            99:        umap_node_hashtbl = hashinit(NUMAPNODECACHE, M_CACHE, &umap_node_hash);
        !           100: }
        !           101: 
        !           102: /*
        !           103:  * umap_findid is called by various routines in umap_vnodeops.c to
        !           104:  * find a user or group id in a map.
        !           105:  */
        !           106: static u_long
        !           107: umap_findid(id, map, nentries)
        !           108:        u_long id;
        !           109:        u_long map[][2];
        !           110:        int nentries;
        !           111: {
        !           112:        int i;
        !           113: 
        !           114:        /* Find uid entry in map */
        !           115:        i = 0;
        !           116:        while ((i<nentries) && ((map[i][0]) != id))
        !           117:                i++;
        !           118: 
        !           119:        if (i < nentries)
        !           120:                return (map[i][1]);
        !           121:        else
        !           122:                return (-1);
        !           123: 
        !           124: }
        !           125: 
        !           126: /*
        !           127:  * umap_reverse_findid is called by umap_getattr() in umap_vnodeops.c to
        !           128:  * find a user or group id in a map, in reverse.
        !           129:  */
        !           130: u_long
        !           131: umap_reverse_findid(id, map, nentries)
        !           132:        u_long id;
        !           133:        u_long map[][2];
        !           134:        int nentries;
        !           135: {
        !           136:        int i;
        !           137: 
        !           138:        /* Find uid entry in map */
        !           139:        i = 0;
        !           140:        while ((i<nentries) && ((map[i][1]) != id))
        !           141:                i++;
        !           142: 
        !           143:        if (i < nentries)
        !           144:                return (map[i][0]);
        !           145:        else
        !           146:                return (-1);
        !           147: 
        !           148: }
        !           149: 
        !           150: /*
        !           151:  * Return alias for target vnode if already exists, else 0.
        !           152:  */
        !           153: static struct vnode *
        !           154: umap_node_find(mp, targetvp)
        !           155:        struct mount *mp;
        !           156:        struct vnode *targetvp;
        !           157: {
        !           158:        struct umap_node_hashhead *hd;
        !           159:        struct umap_node *a;
        !           160:        struct vnode *vp;
        !           161: 
        !           162: #ifdef UMAPFS_DIAGNOSTIC
        !           163:        printf("umap_node_find(mp = %x, target = %x)\n", mp, targetvp);
        !           164: #endif
        !           165: 
        !           166:        /*
        !           167:         * Find hash base, and then search the (two-way) linked
        !           168:         * list looking for a umap_node structure which is referencing
        !           169:         * the target vnode.  If found, the increment the umap_node
        !           170:         * reference count (but NOT the target vnode's VREF counter).
        !           171:         */
        !           172:        hd = UMAP_NHASH(targetvp);
        !           173: loop:
        !           174:        for (a = hd->lh_first; a != 0; a = a->umap_hash.le_next) {
        !           175:                if (a->umap_lowervp == targetvp &&
        !           176:                    a->umap_vnode->v_mount == mp) {
        !           177:                        vp = UMAPTOV(a);
        !           178:                        /*
        !           179:                         * We need vget for the VXLOCK
        !           180:                         * stuff, but we don't want to lock
        !           181:                         * the lower node.
        !           182:                         */
        !           183:                        if (vget(vp, 0)) {
        !           184: #ifdef UMAPFS_DIAGNOSTIC
        !           185:                                printf ("umap_node_find: vget failed.\n");
        !           186: #endif
        !           187:                                goto loop;
        !           188:                        }
        !           189:                        return (vp);
        !           190:                }
        !           191:        }
        !           192: 
        !           193: #ifdef UMAPFS_DIAGNOSTIC
        !           194:        printf("umap_node_find(%x, %x): NOT found\n", mp, targetvp);
        !           195: #endif
        !           196: 
        !           197:        return (0);
        !           198: }
        !           199: 
        !           200: /*
        !           201:  * Make a new umap_node node.
        !           202:  * Vp is the alias vnode, lowervp is the target vnode.
        !           203:  * Maintain a reference to lowervp.
        !           204:  */
        !           205: static int
        !           206: umap_node_alloc(mp, lowervp, vpp)
        !           207:        struct mount *mp;
        !           208:        struct vnode *lowervp;
        !           209:        struct vnode **vpp;
        !           210: {
        !           211:        struct umap_node_hashhead *hd;
        !           212:        struct umap_node *xp;
        !           213:        struct vnode *vp, *nvp;
        !           214:        int error;
        !           215:        extern int (**dead_vnodeop_p)();
        !           216:        struct specinfo *sp = (struct specinfo *)0;
        !           217: 
        !           218:        if (lowervp->v_type == VBLK || lowervp->v_type == VCHR)
        !           219:                MALLOC_ZONE(sp, struct specinfo *, sizeof(struct specinfo), 
        !           220:                        M_VNODE, M_WAITOK);
        !           221: 
        !           222:        MALLOC(xp, struct umap_node *, sizeof(struct umap_node), M_TEMP,
        !           223:            M_WAITOK);
        !           224:        if (error = getnewvnode(VT_UMAP, mp, umap_vnodeop_p, &vp)) {
        !           225:                FREE(xp, M_TEMP);
        !           226:                if (sp)
        !           227:                        FREE_ZONE(sp, sizeof (struct specinfo), M_VNODE);
        !           228:                return (error);
        !           229:        }
        !           230:        vp->v_type = lowervp->v_type;
        !           231: 
        !           232:        if (vp->v_type == VBLK || vp->v_type == VCHR) {
        !           233:                vp->v_specinfo = sp;
        !           234:                vp->v_rdev = lowervp->v_rdev;
        !           235:        }
        !           236: 
        !           237:        vp->v_data = xp;
        !           238:        xp->umap_vnode = vp;
        !           239:        xp->umap_lowervp = lowervp;
        !           240:        /*
        !           241:         * Before we insert our new node onto the hash chains,
        !           242:         * check to see if someone else has beaten us to it.
        !           243:         */
        !           244:        if (nvp = umap_node_find(lowervp)) {
        !           245:                *vpp = nvp;
        !           246: 
        !           247:                /* free the substructures we've allocated. */
        !           248:                FREE(xp, M_TEMP);
        !           249:                if (sp) {
        !           250:                        vp->v_specinfo = (struct specinfo *)0;
        !           251:                        FREE_ZONE(sp, sizeof (struct specinfo), M_VNODE);
        !           252:                }
        !           253: 
        !           254:                vp->v_type = VBAD;              /* node is discarded */
        !           255:                vp->v_op = dead_vnodeop_p;      /* so ops will still work */
        !           256:                vrele(vp);                      /* get rid of it. */
        !           257:                return (0);
        !           258:        }
        !           259: 
        !           260:        /*
        !           261:         * XXX if it's a device node, it needs to be checkalias()ed.
        !           262:         * however, for locking reasons, that's just not possible.
        !           263:         * so we have to do most of the dirty work inline.  Note that
        !           264:         * this is a limited case; we know that there's going to be
        !           265:         * an alias, and we know that that alias will be a "real"
        !           266:         * device node, i.e. not tagged VT_NON.
        !           267:         */
        !           268:        if (vp->v_type == VBLK || vp->v_type == VCHR) {
        !           269:                struct vnode *cvp, **cvpp;
        !           270: 
        !           271:                cvpp = &speclisth[SPECHASH(vp->v_rdev)];
        !           272: loop:
        !           273:                for (cvp = *cvpp; cvp; cvp = cvp->v_specnext) {
        !           274:                        if (vp->v_rdev != cvp->v_rdev ||
        !           275:                            vp->v_type != cvp->v_type)
        !           276:                                continue;
        !           277: 
        !           278:                        /*
        !           279:                         * Alias, but not in use, so flush it out.
        !           280:                         */
        !           281:                        if (cvp->v_usecount == 0) {
        !           282:                                vgone(cvp);
        !           283:                                goto loop;
        !           284:                        }
        !           285:                        if (vget(cvp, 0))       /* can't lock; will die! */
        !           286:                                goto loop;
        !           287:                        break;
        !           288:                }
        !           289: 
        !           290:                vp->v_hashchain = cvpp;
        !           291:                vp->v_specnext = *cvpp;
        !           292:                vp->v_specflags = 0;
        !           293:                *cvpp = vp;
        !           294: #if DIAGNOSTIC
        !           295:                if (cvp == NULLVP)
        !           296:                        panic("umap_node_alloc: no alias for device");
        !           297: #endif
        !           298:                vp->v_flag |= VALIASED;
        !           299:                cvp->v_flag |= VALIASED;
        !           300:                vrele(cvp);
        !           301:        }
        !           302:        /* XXX end of transmogrified checkalias() */
        !           303: 
        !           304:        *vpp = vp;
        !           305:        VREF(lowervp);  /* Extra VREF will be vrele'd in umap_node_create */
        !           306:        hd = UMAP_NHASH(lowervp);
        !           307:        LIST_INSERT_HEAD(hd, xp, umap_hash);
        !           308:        return (0);
        !           309: }
        !           310: 
        !           311: 
        !           312: /*
        !           313:  * Try to find an existing umap_node vnode refering
        !           314:  * to it, otherwise make a new umap_node vnode which
        !           315:  * contains a reference to the target vnode.
        !           316:  */
        !           317: int
        !           318: umap_node_create(mp, targetvp, newvpp)
        !           319:        struct mount *mp;
        !           320:        struct vnode *targetvp;
        !           321:        struct vnode **newvpp;
        !           322: {
        !           323:        struct vnode *aliasvp;
        !           324: 
        !           325:        if (aliasvp = umap_node_find(mp, targetvp)) {
        !           326:                /*
        !           327:                 * Take another reference to the alias vnode
        !           328:                 */
        !           329: #ifdef UMAPFS_DIAGNOSTIC
        !           330:                vprint("umap_node_create: exists", ap->umap_vnode);
        !           331: #endif
        !           332:                /* VREF(aliasvp); */
        !           333:        } else {
        !           334:                int error;
        !           335: 
        !           336:                /*
        !           337:                 * Get new vnode.
        !           338:                 */
        !           339: #ifdef UMAPFS_DIAGNOSTIC
        !           340:                printf("umap_node_create: create new alias vnode\n");
        !           341: #endif
        !           342:                /*
        !           343:                 * Make new vnode reference the umap_node.
        !           344:                 */
        !           345:                if (error = umap_node_alloc(mp, targetvp, &aliasvp))
        !           346:                        return (error);
        !           347: 
        !           348:                /*
        !           349:                 * aliasvp is already VREF'd by getnewvnode()
        !           350:                 */
        !           351:        }
        !           352: 
        !           353:        vrele(targetvp);
        !           354: 
        !           355: #ifdef UMAPFS_DIAGNOSTIC
        !           356:        vprint("umap_node_create: alias", aliasvp);
        !           357:        vprint("umap_node_create: target", targetvp);
        !           358: #endif
        !           359: 
        !           360:        *newvpp = aliasvp;
        !           361:        return (0);
        !           362: }
        !           363: 
        !           364: #ifdef UMAPFS_DIAGNOSTIC
        !           365: int umap_checkvp_barrier = 1;
        !           366: struct vnode *
        !           367: umap_checkvp(vp, fil, lno)
        !           368:        struct vnode *vp;
        !           369:        char *fil;
        !           370:        int lno;
        !           371: {
        !           372:        struct umap_node *a = VTOUMAP(vp);
        !           373: #if 0
        !           374:        /*
        !           375:         * Can't do this check because vop_reclaim runs
        !           376:         * with funny vop vector.
        !           377:         */
        !           378:        if (vp->v_op != umap_vnodeop_p) {
        !           379:                printf ("umap_checkvp: on non-umap-node\n");
        !           380:                while (umap_checkvp_barrier) /*WAIT*/ ;
        !           381:                panic("umap_checkvp");
        !           382:        }
        !           383: #endif
        !           384:        if (a->umap_lowervp == NULL) {
        !           385:                /* Should never happen */
        !           386:                int i; u_long *p;
        !           387:                printf("vp = %x, ZERO ptr\n", vp);
        !           388:                for (p = (u_long *) a, i = 0; i < 8; i++)
        !           389:                        printf(" %x", p[i]);
        !           390:                printf("\n");
        !           391:                /* wait for debugger */
        !           392:                while (umap_checkvp_barrier) /*WAIT*/ ;
        !           393:                panic("umap_checkvp");
        !           394:        }
        !           395:        if (a->umap_lowervp->v_usecount < 1) {
        !           396:                int i; u_long *p;
        !           397:                printf("vp = %x, unref'ed lowervp\n", vp);
        !           398:                for (p = (u_long *) a, i = 0; i < 8; i++)
        !           399:                        printf(" %x", p[i]);
        !           400:                printf("\n");
        !           401:                /* wait for debugger */
        !           402:                while (umap_checkvp_barrier) /*WAIT*/ ;
        !           403:                panic ("umap with unref'ed lowervp");
        !           404:        }
        !           405: #if 0
        !           406:        printf("umap %x/%d -> %x/%d [%s, %d]\n",
        !           407:                a->umap_vnode, a->umap_vnode->v_usecount,
        !           408:                a->umap_lowervp, a->umap_lowervp->v_usecount,
        !           409:                fil, lno);
        !           410: #endif
        !           411:        return (a->umap_lowervp);
        !           412: }
        !           413: #endif
        !           414: 
        !           415: /* umap_mapids maps all of the ids in a credential, both user and group. */
        !           416: 
        !           417: void
        !           418: umap_mapids(v_mount, credp)
        !           419:        struct mount *v_mount;
        !           420:        struct ucred *credp;
        !           421: {
        !           422:        int i, unentries, gnentries;
        !           423:        uid_t uid, *usermap;
        !           424:        gid_t gid, *groupmap;
        !           425: 
        !           426:        unentries =  MOUNTTOUMAPMOUNT(v_mount)->info_nentries;
        !           427:        usermap =  &(MOUNTTOUMAPMOUNT(v_mount)->info_mapdata[0][0]);
        !           428:        gnentries =  MOUNTTOUMAPMOUNT(v_mount)->info_gnentries;
        !           429:        groupmap =  &(MOUNTTOUMAPMOUNT(v_mount)->info_gmapdata[0][0]);
        !           430: 
        !           431:        /* Find uid entry in map */
        !           432: 
        !           433:        uid = (uid_t) umap_findid(credp->cr_uid, usermap, unentries);
        !           434: 
        !           435:        if (uid != -1)
        !           436:                credp->cr_uid = uid;
        !           437:        else
        !           438:                credp->cr_uid = (uid_t) NOBODY;
        !           439: 
        !           440: #ifdef notdef
        !           441:        /* cr_gid is the same as cr_groups[0] in 4BSD */
        !           442: 
        !           443:        /* Find gid entry in map */
        !           444: 
        !           445:        gid = (gid_t) umap_findid(credp->cr_gid, groupmap, gnentries);
        !           446: 
        !           447:        if (gid != -1)
        !           448:                credp->cr_gid = gid;
        !           449:        else
        !           450:                credp->cr_gid = NULLGROUP;
        !           451: #endif
        !           452: 
        !           453:        /* Now we must map each of the set of groups in the cr_groups 
        !           454:                structure. */
        !           455: 
        !           456:        i = 0;
        !           457:        while (credp->cr_groups[i] != 0) {
        !           458:                gid = (gid_t) umap_findid(credp->cr_groups[i],
        !           459:                                        groupmap, gnentries);
        !           460: 
        !           461:                if (gid != -1)
        !           462:                        credp->cr_groups[i++] = gid;
        !           463:                else
        !           464:                        credp->cr_groups[i++] = NULLGROUP;
        !           465:        }
        !           466: }

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