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  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*      $NetBSD: cd9660_bmap.c,v 1.5 1994/12/13 22:33:12 mycroft Exp $  */
  26
  27 /*-
  28  * Copyright (c) 1994
  29  *      The Regents of the University of California.  All rights reserved.
  30  *
  31  * This code is derived from software contributed to Berkeley
  32  * by Pace Willisson (pace@blitz.com).  The Rock Ridge Extension
  33  * Support code is derived from software contributed to Berkeley
  34  * by Atsushi Murai (amurai@spec.co.jp).
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 3. All advertising materials mentioning features or use of this software
  45  *    must display the following acknowledgement:
  46  *      This product includes software developed by the University of
  47  *      California, Berkeley and its contributors.
  48  * 4. Neither the name of the University nor the names of its contributors
  49  *    may be used to endorse or promote products derived from this software
  50  *    without specific prior written permission.
  51  *
  52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  62  * SUCH DAMAGE.
  63  *
  64  *      @(#)cd9660_bmap.c       8.4 (Berkeley) 12/5/94
  65  */
  66
  67 #include <sys/param.h>
  68 #include <sys/vnode.h>
  69 #include <sys/mount.h>
  70 #include <sys/namei.h>
  71 #include <sys/buf.h>
  72 #include <sys/file.h>
  73
  74 #include <isofs/cd9660/iso.h>
  75 #include <isofs/cd9660/cd9660_node.h>
  76
  77 /*
  78  * Bmap converts the logical block number of a file to its physical block
  79  * number on the disk. The conversion is done by using the logical block
  80  * number to index into the data block (extent) for the file.
  81  */
  82 int
  83 cd9660_bmap(ap)
  84         struct vop_bmap_args /* {
  85                 struct vnode *a_vp;
  86                 daddr_t  a_bn;
  87                 struct vnode **a_vpp;
  88                 daddr_t *a_bnp;
  89                 int *a_runp;
  90         } */ *ap;
  91 {
  92         struct iso_node *ip = VTOI(ap->a_vp);
  93         daddr_t lblkno = ap->a_bn;
  94         int bshift;
  95
  96         /*
  97          * Check for underlying vnode requests and ensure that logical
  98          * to physical mapping is requested.
  99          */
 100         if (ap->a_vpp != NULL)
 101                 *ap->a_vpp = ip->i_devvp;
 102         if (ap->a_bnp == NULL)
 103                 return (0);
 104
 105         /*
 106          * Associated files have an Apple Double header
 107          */
 108         if ((ip->i_flag & ISO_ASSOCIATED) && (lblkno > (ADH_BLKS - 1))) {
 109                 lblkno -= ADH_BLKS;
 110                 *ap->a_bnp = (ip->iso_start + lblkno);
 111                 if (ap->a_runp)
 112                         *ap->a_runp = 0;
 113                 return (0);
 114         }
 115
 116         /*
 117          * Compute the requested block number
 118          */
 119         bshift = ip->i_mnt->im_bshift;
 120         *ap->a_bnp = (ip->iso_start + lblkno);
 121
 122         /*
 123          * Determine maximum number of readahead blocks following the
 124          * requested block.
 125          */
 126         if (ap->a_runp) {
 127                 int nblk;
 128
 129                 nblk = (ip->i_size >> bshift) - (lblkno + 1);
 130                 if (nblk <= 0)
 131                         *ap->a_runp = 0;
 132                 else if (nblk >= (MAXBSIZE >> bshift))
 133                         *ap->a_runp = (MAXBSIZE >> bshift) - 1;
 134                 else
 135                         *ap->a_runp = nblk;
 136         }
 137
 138         return (0);
 139 }
 140
 141 /* blktooff converts a logical block number to a file offset */
 142 int
 143 cd9660_blktooff(ap)
 144         struct vop_blktooff_args /* {
 145                 struct vnode *a_vp;
 146                 daddr_t a_lblkno;
 147                 off_t *a_offset;
 148         } */ *ap;
 149 {
 150         register struct iso_node *ip;
 151         register struct iso_mnt *imp;
 152
 153         if (ap->a_vp == NULL)
 154                 return (EINVAL);
 155
 156         ip = VTOI(ap->a_vp);
 157         imp = ip->i_mnt;
 158
 159         *ap->a_offset = (off_t)lblktosize(imp, ap->a_lblkno);
 160         return (0);
 161 }
 162
 163 /* offtoblk converts a file offset to a logical block number */
 164 int
 165 cd9660_offtoblk(ap)
 166 struct vop_offtoblk_args /* {
 167         struct vnode *a_vp;
 168         off_t a_offset;
 169         daddr_t *a_lblkno;
 170         } */ *ap;
 171 {
 172         register struct iso_node *ip;
 173         register struct iso_mnt *imp;
 174
 175         if (ap->a_vp == NULL)
 176                 return (EINVAL);
 177
 178         ip = VTOI(ap->a_vp);
 179         imp = ip->i_mnt;
 180
 181         *ap->a_lblkno = (daddr_t)lblkno(imp, ap->a_offset);
 182         return (0);
 183 }
 184
 185 int
 186 cd9660_cmap(ap)
 187 struct vop_cmap_args /* {
 188         struct vnode *a_vp;
 189         off_t a_offset;
 190         size_t a_size;
 191         daddr_t *a_bpn;
 192         size_t *a_run;
 193         void *a_poff;
 194 } */ *ap;
 195 {
 196         struct iso_node *ip = VTOI(ap->a_vp);
 197         size_t cbytes;
 198         int devBlockSize = 0;
 199         off_t offset = ap->a_foffset;
 200
 201         /*
 202          * Check for underlying vnode requests and ensure that logical
 203          * to physical mapping is requested.
 204          */
 205         if (ap->a_bpn == NULL)
 206                 return (0);
 207
 208         VOP_DEVBLOCKSIZE(ip->i_devvp, &devBlockSize);
 209
 210         /*
 211          * Associated files have an Apple Double header
 212          */
 213         if (ip->i_flag & ISO_ASSOCIATED) {
 214                 if (offset < ADH_SIZE) {
 215                         if (ap->a_run)
 216                                 *ap->a_run = 0;
 217                         *ap->a_bpn = -1;
 218                         goto out;
 219                 } else {
 220                         offset -= ADH_SIZE;
 221                 }
 222         }
 223
 224         *ap->a_bpn = (daddr_t)(ip->iso_start + lblkno(ip->i_mnt, offset));
 225
 226         /*
 227          * Determine maximum number of contiguous bytes following the
 228          * requested offset.
 229          */
 230         if (ap->a_run) {
 231                 if (ip->i_size > offset)
 232                         cbytes = ip->i_size - offset;
 233                 else
 234                         cbytes = 0;
 235
 236                 cbytes = (cbytes + (devBlockSize - 1)) & ~(devBlockSize - 1);
 237
 238                 *ap->a_run = MIN(cbytes, ap->a_size);
 239         };
 240 out:
 241         if (ap->a_poff)
 242                 *(int *)ap->a_poff = (long)offset & (devBlockSize - 1);
 243
 244         return (0);
 245 }
 246