usr/src/lib/libtnf/access.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  *      Copyright (c) 1994, by Sun Microsytems, Inc.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27
  28 #include "libtnf.h"
  29
  30 /*
  31  * File header operations
  32  */
  33
  34 tnf_datum_t
  35 tnf_get_file_header(TNF *tnf)
  36 {
  37         return (DATUM(tnf->file_header_info, (caddr_t)tnf->file_header));
  38 }
  39
  40 /*
  41  * Block access operations
  42  */
  43
  44 unsigned
  45 tnf_get_block_count(TNF *tnf)
  46 {
  47         return (tnf->block_count);
  48 }
  49
  50 tnf_datum_t
  51 tnf_get_block_absolute(TNF *tnf, unsigned index)
  52 {
  53         if (index >= tnf->block_count)
  54                 /*
  55                  * access to non-existent block:
  56                  * no error as per spec
  57                  */
  58                 return (TNF_DATUM_NULL);
  59         else
  60                 /*
  61                  * XXX Require a single block header tag
  62                  */
  63                 /* LINTED pointer cast may result in improper alignment */
  64                 return (DATUM(tnf->block_header_info,
  65                             (caddr_t)_GET_INDEX_BLOCK(tnf, index)));
  66 }
  67
  68 tnf_datum_t
  69 tnf_get_block_relative(tnf_datum_t datum, int adjust)
  70 {
  71         TNF             *tnf;
  72         tnf_ref32_t     *bhdr;
  73         unsigned        index;
  74
  75         CHECK_DATUM(datum);
  76
  77         tnf     = DATUM_TNF(datum);
  78         bhdr    = _GET_BLOCK(tnf, DATUM_VAL(datum));
  79         index   = _GET_BLOCK_INDEX(tnf, bhdr);
  80
  81         return (tnf_get_block_absolute(tnf, index + adjust));
  82 }
  83
  84 int
  85 tnf_is_block_header(tnf_datum_t datum)
  86 {
  87         struct taginfo  *info;
  88         caddr_t         val;
  89         tnf_ref32_t     *bhdr;
  90
  91         CHECK_DATUM(datum);
  92
  93         info    = DATUM_INFO(datum);
  94         val     = DATUM_VAL(datum);
  95         bhdr    = _GET_BLOCK(info->tnf, val);
  96
  97         return (((caddr_t)bhdr == val) &&
  98                 (info == info->tnf->block_header_info));
  99 }
 100
 101 tnf_datum_t
 102 tnf_get_block_header(tnf_datum_t datum)
 103 {
 104         TNF     *tnf;
 105         caddr_t val;
 106
 107         CHECK_DATUM(datum);
 108
 109         tnf     = DATUM_TNF(datum);
 110         val     = DATUM_VAL(datum);
 111         /*
 112          * XXX Require a single block header tag
 113          */
 114         return (DATUM(tnf->block_header_info, (caddr_t)_GET_BLOCK(tnf, val)));
 115 }
 116
 117 /*
 118  * Sequential record access
 119  */
 120
 121 tnf_datum_t
 122 tnf_get_next_record(tnf_datum_t datum)
 123 {
 124         TNF             *tnf;
 125         tnf_ref32_t     *bhdr, *cell, ref32;
 126         caddr_t         val, nval, bval, blim;
 127         size_t          size, bytes;
 128
 129         CHECK_RECORD(datum);
 130
 131         tnf     = DATUM_TNF(datum);
 132         val     = DATUM_VAL(datum);
 133
 134         size    = tnf_get_size(datum);
 135         nval    = val + size;
 136
 137         /* Check file bounds */
 138         if (nval < tnf->data_start)
 139                 return (tnf_get_block_absolute(tnf, 0));
 140         else if (nval >= tnf->file_end)
 141                 return (TNF_DATUM_NULL);
 142
 143         /*
 144          * OK, nval is in data area, start looking in block
 145          */
 146         bhdr    = _GET_BLOCK(tnf, nval);
 147         /* LINTED pointer cast may result in improper alignment */
 148         bytes   = _GET_BLOCK_BYTES_VALID(tnf, bhdr);
 149         bval    = (caddr_t)bhdr;
 150         blim    = bval + bytes;
 151
 152         /* sequentially examine valid cells in block from nval onwards */
 153         while (nval < blim) {
 154                 /* LINTED pointer cast may result in improper alignment */
 155                 cell    = (tnf_ref32_t *)nval;
 156                 ref32   = _GET_INT32(tnf, cell);
 157
 158                 switch (TNF_REF32_TYPE(ref32)) {
 159                 case TNF_REF32_T_FWD: /* skip forwarding cells */
 160                         nval += sizeof (tnf_ref32_t);
 161                         break;
 162                 case TNF_REF32_T_RSVD: /* catch bogus cells */
 163                         _tnf_error(tnf, TNF_ERR_BADTNF);
 164                         return (TNF_DATUM_NULL);
 165                 default:        /* PAIR or TAG: record header */
 166                         return (RECORD_DATUM(tnf, cell));
 167                 }
 168         }
 169
 170         /*
 171          * Couldn't find it: return next non-zero block header
 172          */
 173         while ((bval += tnf->block_size) < tnf->file_end)
 174                 /* Gotta check that there is a real bhdr here */
 175                 /* LINTED pointer cast may result in improper alignment */
 176                 if (*(tnf_ref32_t *)bval != TNF_NULL)
 177                 /* LINTED pointer cast may result in improper alignment */
 178                         return (RECORD_DATUM(tnf, (tnf_ref32_t *)bval));
 179
 180         /*
 181          * default: we're off the end of the file
 182          */
 183         return (TNF_DATUM_NULL);
 184 }