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Annotation of XNU/bsd/vfs/vfs_init.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: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
        !            23: /*
        !            24:  * Copyright (c) 1989, 1993
        !            25:  *     The Regents of the University of California.  All rights reserved.
        !            26:  *
        !            27:  * This code is derived from software contributed
        !            28:  * to Berkeley by John Heidemann of the UCLA Ficus project.
        !            29:  *
        !            30:  * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
        !            31:  *
        !            32:  * Redistribution and use in source and binary forms, with or without
        !            33:  * modification, are permitted provided that the following conditions
        !            34:  * are met:
        !            35:  * 1. Redistributions of source code must retain the above copyright
        !            36:  *    notice, this list of conditions and the following disclaimer.
        !            37:  * 2. Redistributions in binary form must reproduce the above copyright
        !            38:  *    notice, this list of conditions and the following disclaimer in the
        !            39:  *    documentation and/or other materials provided with the distribution.
        !            40:  * 3. All advertising materials mentioning features or use of this software
        !            41:  *    must display the following acknowledgement:
        !            42:  *     This product includes software developed by the University of
        !            43:  *     California, Berkeley and its contributors.
        !            44:  * 4. Neither the name of the University nor the names of its contributors
        !            45:  *    may be used to endorse or promote products derived from this software
        !            46:  *    without specific prior written permission.
        !            47:  *
        !            48:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            49:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            50:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            51:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            52:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            53:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            54:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            55:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            56:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            57:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            58:  * SUCH DAMAGE.
        !            59:  *
        !            60:  *     @(#)vfs_init.c  8.5 (Berkeley) 5/11/95
        !            61:  */
        !            62: 
        !            63: 
        !            64: #include <sys/param.h>
        !            65: #include <sys/mount.h>
        !            66: #include <sys/time.h>
        !            67: #include <sys/vm.h>
        !            68: #include <sys/vnode.h>
        !            69: #include <sys/stat.h>
        !            70: #include <sys/namei.h>
        !            71: #include <sys/ucred.h>
        !            72: #include <sys/buf.h>
        !            73: #include <sys/errno.h>
        !            74: #include <sys/malloc.h>
        !            75: 
        !            76: 
        !            77: /*
        !            78:  * Sigh, such primitive tools are these...
        !            79:  */
        !            80: #if 0
        !            81: #define DODEBUG(A) A
        !            82: #else
        !            83: #define DODEBUG(A)
        !            84: #endif
        !            85: 
        !            86: extern struct vnodeopv_desc *vfs_opv_descs[];
        !            87:                                /* a list of lists of vnodeops defns */
        !            88: extern struct vnodeop_desc *vfs_op_descs[];
        !            89:                                /* and the operations they perform */
        !            90: /*
        !            91:  * This code doesn't work if the defn is **vnodop_defns with cc.
        !            92:  * The problem is because of the compiler sometimes putting in an
        !            93:  * extra level of indirection for arrays.  It's an interesting
        !            94:  * "feature" of C.
        !            95:  */
        !            96: int vfs_opv_numops;
        !            97: 
        !            98: typedef (*PFI)();   /* the standard Pointer to a Function returning an Int */
        !            99: 
        !           100: /*
        !           101:  * A miscellaneous routine.
        !           102:  * A generic "default" routine that just returns an error.
        !           103:  */
        !           104: int
        !           105: vn_default_error()
        !           106: {
        !           107: 
        !           108:        return (EOPNOTSUPP);
        !           109: }
        !           110: 
        !           111: /*
        !           112:  * vfs_init.c
        !           113:  *
        !           114:  * Allocate and fill in operations vectors.
        !           115:  *
        !           116:  * An undocumented feature of this approach to defining operations is that
        !           117:  * there can be multiple entries in vfs_opv_descs for the same operations
        !           118:  * vector. This allows third parties to extend the set of operations
        !           119:  * supported by another layer in a binary compatibile way. For example,
        !           120:  * assume that NFS needed to be modified to support Ficus. NFS has an entry
        !           121:  * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
        !           122:  * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
        !           123:  * listing those new operations Ficus adds to NFS, all without modifying the
        !           124:  * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
        !           125:  * that is a(whole)nother story.) This is a feature.
        !           126:  */
        !           127: void
        !           128: vfs_opv_init()
        !           129: {
        !           130:        int i, j, k;
        !           131:        int (***opv_desc_vector_p)();
        !           132:        int (**opv_desc_vector)();
        !           133:        struct vnodeopv_entry_desc *opve_descp;
        !           134: 
        !           135:        /*
        !           136:         * Allocate the dynamic vectors and fill them in.
        !           137:         */
        !           138:        for (i=0; vfs_opv_descs[i]; i++) {
        !           139:                opv_desc_vector_p = vfs_opv_descs[i]->opv_desc_vector_p;
        !           140:                /*
        !           141:                 * Allocate and init the vector, if it needs it.
        !           142:                 * Also handle backwards compatibility.
        !           143:                 */
        !           144:                if (*opv_desc_vector_p == NULL) {
        !           145:                        /* XXX - shouldn't be M_VNODE */
        !           146:                        MALLOC(*opv_desc_vector_p, PFI*,
        !           147:                               vfs_opv_numops*sizeof(PFI), M_VNODE, M_WAITOK);
        !           148:                        bzero (*opv_desc_vector_p, vfs_opv_numops*sizeof(PFI));
        !           149:                        DODEBUG(printf("vector at %x allocated\n",
        !           150:                            opv_desc_vector_p));
        !           151:                }
        !           152:                opv_desc_vector = *opv_desc_vector_p;
        !           153:                for (j=0; vfs_opv_descs[i]->opv_desc_ops[j].opve_op; j++) {
        !           154:                        opve_descp = &(vfs_opv_descs[i]->opv_desc_ops[j]);
        !           155: 
        !           156:                        /*
        !           157:                         * Sanity check:  is this operation listed
        !           158:                         * in the list of operations?  We check this
        !           159:                         * by seeing if its offest is zero.  Since
        !           160:                         * the default routine should always be listed
        !           161:                         * first, it should be the only one with a zero
        !           162:                         * offset.  Any other operation with a zero
        !           163:                         * offset is probably not listed in
        !           164:                         * vfs_op_descs, and so is probably an error.
        !           165:                         *
        !           166:                         * A panic here means the layer programmer
        !           167:                         * has committed the all-too common bug
        !           168:                         * of adding a new operation to the layer's
        !           169:                         * list of vnode operations but
        !           170:                         * not adding the operation to the system-wide
        !           171:                         * list of supported operations.
        !           172:                         */
        !           173:                        if (opve_descp->opve_op->vdesc_offset == 0 &&
        !           174:                                    opve_descp->opve_op->vdesc_offset !=
        !           175:                                        VOFFSET(vop_default)) {
        !           176:                                printf("operation %s not listed in %s.\n",
        !           177:                                    opve_descp->opve_op->vdesc_name,
        !           178:                                    "vfs_op_descs");
        !           179:                                panic ("vfs_opv_init: bad operation");
        !           180:                        }
        !           181:                        /*
        !           182:                         * Fill in this entry.
        !           183:                         */
        !           184:                        opv_desc_vector[opve_descp->opve_op->vdesc_offset] =
        !           185:                                        opve_descp->opve_impl;
        !           186:                }
        !           187:        }
        !           188:        /*
        !           189:         * Finally, go back and replace unfilled routines
        !           190:         * with their default.  (Sigh, an O(n^3) algorithm.  I
        !           191:         * could make it better, but that'd be work, and n is small.)
        !           192:         */
        !           193:        for (i = 0; vfs_opv_descs[i]; i++) {
        !           194:                opv_desc_vector = *(vfs_opv_descs[i]->opv_desc_vector_p);
        !           195:                /*
        !           196:                 * Force every operations vector to have a default routine.
        !           197:                 */
        !           198:                if (opv_desc_vector[VOFFSET(vop_default)]==NULL) {
        !           199:                        panic("vfs_opv_init: operation vector without default routine.");
        !           200:                }
        !           201:                for (k = 0; k<vfs_opv_numops; k++)
        !           202:                        if (opv_desc_vector[k] == NULL)
        !           203:                                opv_desc_vector[k] = 
        !           204:                                        opv_desc_vector[VOFFSET(vop_default)];
        !           205:        }
        !           206: }
        !           207: 
        !           208: /*
        !           209:  * Initialize known vnode operations vectors.
        !           210:  */
        !           211: void
        !           212: vfs_op_init()
        !           213: {
        !           214:        int i;
        !           215: 
        !           216:        DODEBUG(printf("Vnode_interface_init.\n"));
        !           217:        /*
        !           218:         * Set all vnode vectors to a well known value.
        !           219:         */
        !           220:        for (i = 0; vfs_opv_descs[i]; i++)
        !           221:                *(vfs_opv_descs[i]->opv_desc_vector_p) = NULL;
        !           222:        /*
        !           223:         * Figure out how many ops there are by counting the table,
        !           224:         * and assign each its offset.
        !           225:         */
        !           226:        for (vfs_opv_numops = 0, i = 0; vfs_op_descs[i]; i++) {
        !           227:                vfs_op_descs[i]->vdesc_offset = vfs_opv_numops;
        !           228:                vfs_opv_numops++;
        !           229:        }
        !           230:        DODEBUG(printf ("vfs_opv_numops=%d\n", vfs_opv_numops));
        !           231: }
        !           232: 
        !           233: /*
        !           234:  * Routines having to do with the management of the vnode table.
        !           235:  */
        !           236: extern struct vnodeops dead_vnodeops;
        !           237: extern struct vnodeops spec_vnodeops;
        !           238: struct vattr va_null;
        !           239: 
        !           240: /*
        !           241:  * Initialize the vnode structures and initialize each file system type.
        !           242:  */
        !           243: vfsinit()
        !           244: {
        !           245:        struct vfsconf *vfsp;
        !           246:        int i, maxtypenum;
        !           247: 
        !           248:        /*
        !           249:         * Initialize the vnode table
        !           250:         */
        !           251:        vntblinit();
        !           252:        /*
        !           253:         * Initialize the vnode name cache
        !           254:         */
        !           255:        nchinit();
        !           256:        /*
        !           257:         * Build vnode operation vectors.
        !           258:         */
        !           259:        vfs_op_init();
        !           260:        vfs_opv_init();   /* finish the job */
        !           261:        /*
        !           262:         * Initialize each file system type.
        !           263:         */
        !           264:        vattr_null(&va_null);
        !           265:        numused_vfsslots = maxtypenum = 0;
        !           266:        for (vfsp = vfsconf, i = 0; i < maxvfsconf; i++, vfsp++) {
        !           267:                if (vfsp->vfc_vfsops == (struct vfsops *)0)
        !           268:                        break;
        !           269:                if (i) vfsconf[i-1].vfc_next = vfsp;
        !           270:                if (maxtypenum <= vfsp->vfc_typenum)
        !           271:                        maxtypenum = vfsp->vfc_typenum + 1;
        !           272:                (*vfsp->vfc_vfsops->vfs_init)(vfsp);
        !           273:                numused_vfsslots++;
        !           274:        }
        !           275:        /* next vfc_typenum to be used */
        !           276:        maxvfsconf = maxtypenum;
        !           277: }
        !           278: 
        !           279: int vfsconf_add(struct vfsconf *nvfsp)
        !           280: {
        !           281:        struct vfsconf *vfsp;
        !           282: 
        !           283:        if ((numused_vfsslots >= maxvfsslots) || (nvfsp == (struct vfsconf *)0))
        !           284:                return (-1);
        !           285:        bcopy(nvfsp, &vfsconf[numused_vfsslots], sizeof(struct vfsconf));
        !           286:        vfsconf[numused_vfsslots-1].vfc_next = &vfsconf[numused_vfsslots];
        !           287:        
        !           288:        if (nvfsp->vfc_typenum <= maxvfsconf )
        !           289:                        maxvfsconf = nvfsp->vfc_typenum + 1;
        !           290:        numused_vfsslots++;
        !           291:        if (nvfsp->vfc_vfsops->vfs_init)
        !           292:                (*nvfsp->vfc_vfsops->vfs_init)(nvfsp);
        !           293:        return(0);
        !           294: }
        !           295: 
        !           296: int vfsconf_del(char * fs_name)
        !           297: {
        !           298: int entriesRemaining;
        !           299:     struct vfsconf *vfsconflistentry;
        !           300:     struct vfsconf *prevconf = NULL;
        !           301:     struct vfsconf *targetconf = NULL;
        !           302: 
        !           303:     prevconf = vfsconflistentry = vfsconf;
        !           304:     for (entriesRemaining = maxvfsslots;
        !           305:          (entriesRemaining > 0) && (vfsconflistentry != NULL);
        !           306:          --entriesRemaining) {
        !           307:         if ((vfsconflistentry->vfc_vfsops != NULL) && (strcmp(vfsconflistentry->vfc_name, fs_name) == 0)) {
        !           308:             targetconf = vfsconflistentry;
        !           309:             break;
        !           310:         };
        !           311:         prevconf = vfsconflistentry;
        !           312:         vfsconflistentry = vfsconflistentry->vfc_next;
        !           313:     };
        !           314: 
        !           315:     if (targetconf != NULL) {
        !           316:         if (prevconf != NULL) {
        !           317:             /* Unlink the target entry from the list: 
        !           318:               and decrement our count                */
        !           319:             prevconf->vfc_next = targetconf->vfc_next;
        !           320:            numused_vfsslots--;
        !           321:         } else {
        !           322:            /* XXX need real error code for no previous entry in list */
        !           323:             return(-1);
        !           324:         }
        !           325:     } else {
        !           326:           /* XXX need real error code for entry not found */
        !           327:           return(-1);
        !           328:     };
        !           329:        return(0);
        !           330: }

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