bsd/isofs/cd9660/cd9660_bmap.c

   1 /*
   2  * Copyright (c) 2000-2003 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: cd9660_bmap.c,v 1.5 1994/12/13 22:33:12 mycroft Exp $  */
  23
  24 /*-
  25  * Copyright (c) 1994
  26  *      The Regents of the University of California.  All rights reserved.
  27  *
  28  * This code is derived from software contributed to Berkeley
  29  * by Pace Willisson (pace@blitz.com).  The Rock Ridge Extension
  30  * Support code is derived from software contributed to Berkeley
  31  * by Atsushi Murai (amurai@spec.co.jp).
  32  *
  33  * Redistribution and use in source and binary forms, with or without
  34  * modification, are permitted provided that the following conditions
  35  * are met:
  36  * 1. Redistributions of source code must retain the above copyright
  37  *    notice, this list of conditions and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  * 3. All advertising materials mentioning features or use of this software
  42  *    must display the following acknowledgement:
  43  *      This product includes software developed by the University of
  44  *      California, Berkeley and its contributors.
  45  * 4. Neither the name of the University nor the names of its contributors
  46  *    may be used to endorse or promote products derived from this software
  47  *    without specific prior written permission.
  48  *
  49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  59  * SUCH DAMAGE.
  60  *
  61  *      @(#)cd9660_bmap.c       8.4 (Berkeley) 12/5/94
  62  */
  63
  64 #include <sys/param.h>
  65 #include <sys/vnode.h>
  66 #include <sys/mount.h>
  67 #include <sys/namei.h>
  68 #include <sys/buf.h>
  69 #include <sys/file.h>
  70
  71 #include <isofs/cd9660/iso.h>
  72 #include <isofs/cd9660/cd9660_node.h>
  73
  74 /*
  75  * Bmap converts the logical block number of a file to its physical block
  76  * number on the disk. The conversion is done by using the logical block
  77  * number to index into the data block (extent) for the file.
  78  */
  79 int
  80 cd9660_bmap(ap)
  81         struct vop_bmap_args /* {
  82                 struct vnode *a_vp;
  83                 daddr_t  a_bn;
  84                 struct vnode **a_vpp;
  85                 daddr_t *a_bnp;
  86                 int *a_runp;
  87         } */ *ap;
  88 {
  89         struct iso_node *ip = VTOI(ap->a_vp);
  90         daddr_t lblkno = ap->a_bn;
  91         int bshift;
  92
  93         /*
  94          * Check for underlying vnode requests and ensure that logical
  95          * to physical mapping is requested.
  96          */
  97         if (ap->a_vpp != NULL)
  98                 *ap->a_vpp = ip->i_devvp;
  99         if (ap->a_bnp == NULL)
 100                 return (0);
 101
 102         /*
 103          * Associated files have an Apple Double header
 104          */
 105         if ((ip->i_flag & ISO_ASSOCIATED) && (lblkno > (ADH_BLKS - 1))) {
 106                 lblkno -= ADH_BLKS;
 107                 *ap->a_bnp = (ip->iso_start + lblkno);
 108                 if (ap->a_runp)
 109                         *ap->a_runp = 0;
 110                 return (0);
 111         }
 112
 113         /*
 114          * Compute the requested block number
 115          */
 116         bshift = ip->i_mnt->im_bshift;
 117         *ap->a_bnp = (ip->iso_start + lblkno);
 118
 119         /*
 120          * Determine maximum number of readahead blocks following the
 121          * requested block.
 122          */
 123         if (ap->a_runp) {
 124                 int nblk;
 125
 126                 nblk = (ip->i_size >> bshift) - (lblkno + 1);
 127                 if (nblk <= 0)
 128                         *ap->a_runp = 0;
 129                 else if (nblk >= (MAXBSIZE >> bshift))
 130                         *ap->a_runp = (MAXBSIZE >> bshift) - 1;
 131                 else
 132                         *ap->a_runp = nblk;
 133         }
 134
 135         return (0);
 136 }
 137
 138 /* blktooff converts a logical block number to a file offset */
 139 int
 140 cd9660_blktooff(ap)
 141         struct vop_blktooff_args /* {
 142                 struct vnode *a_vp;
 143                 daddr_t a_lblkno;
 144                 off_t *a_offset;
 145         } */ *ap;
 146 {
 147         register struct iso_node *ip;
 148         register struct iso_mnt *imp;
 149
 150         if (ap->a_vp == NULL)
 151                 return (EINVAL);
 152
 153         ip = VTOI(ap->a_vp);
 154         imp = ip->i_mnt;
 155
 156         *ap->a_offset = (off_t)lblktosize(imp, ap->a_lblkno);
 157         return (0);
 158 }
 159
 160 /* offtoblk converts a file offset to a logical block number */
 161 int
 162 cd9660_offtoblk(ap)
 163 struct vop_offtoblk_args /* {
 164         struct vnode *a_vp;
 165         off_t a_offset;
 166         daddr_t *a_lblkno;
 167         } */ *ap;
 168 {
 169         register struct iso_node *ip;
 170         register struct iso_mnt *imp;
 171
 172         if (ap->a_vp == NULL)
 173                 return (EINVAL);
 174
 175         ip = VTOI(ap->a_vp);
 176         imp = ip->i_mnt;
 177
 178         *ap->a_lblkno = (daddr_t)lblkno(imp, ap->a_offset);
 179         return (0);
 180 }
 181
 182 int
 183 cd9660_cmap(ap)
 184 struct vop_cmap_args /* {
 185         struct vnode *a_vp;
 186         off_t a_offset;
 187         size_t a_size;
 188         daddr_t *a_bpn;
 189         size_t *a_run;
 190         void *a_poff;
 191 } */ *ap;
 192 {
 193         struct iso_node *ip = VTOI(ap->a_vp);
 194         size_t cbytes;
 195         int devBlockSize = 0;
 196         off_t offset = ap->a_foffset;
 197
 198         /*
 199          * Check for underlying vnode requests and ensure that logical
 200          * to physical mapping is requested.
 201          */
 202         if (ap->a_bpn == NULL)
 203                 return (0);
 204
 205         VOP_DEVBLOCKSIZE(ip->i_devvp, &devBlockSize);
 206
 207         /*
 208          * Associated files have an Apple Double header
 209          */
 210         if (ip->i_flag & ISO_ASSOCIATED) {
 211                 if (offset < ADH_SIZE) {
 212                         if (ap->a_run)
 213                                 *ap->a_run = 0;
 214                         *ap->a_bpn = -1;
 215                         goto out;
 216                 } else {
 217                         offset -= ADH_SIZE;
 218                 }
 219         }
 220
 221         *ap->a_bpn = (daddr_t)(ip->iso_start + lblkno(ip->i_mnt, offset));
 222
 223         /*
 224          * Determine maximum number of contiguous bytes following the
 225          * requested offset.
 226          */
 227         if (ap->a_run) {
 228                 if (ip->i_size > offset)
 229                         cbytes = ip->i_size - offset;
 230                 else
 231                         cbytes = 0;
 232
 233                 cbytes = (cbytes + (devBlockSize - 1)) & ~(devBlockSize - 1);
 234
 235                 *ap->a_run = MIN(cbytes, ap->a_size);
 236         };
 237 out:
 238         if (ap->a_poff)
 239                 *(int *)ap->a_poff = (long)offset & (devBlockSize - 1);
 240
 241         return (0);
 242 }
 243