usr/src/lib/libtnf/reader.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  * Initiate a reader session
  32  */
  33
  34 tnf_errcode_t
  35 tnf_reader_begin(caddr_t base, size_t size, TNF **tnfret)
  36 {
  37         tnf_uint32_t    magic;
  38         int             native;
  39         TNF             *tnf;
  40         tnf_ref32_t     *fhdr, *bhdr;
  41         size_t          tmpsz;
  42         caddr_t         p, genp, bvp;
  43         tnf_errcode_t   err;
  44
  45         /*
  46          * Check magic number
  47          */
  48
  49         /* LINTED pointer cast may result in improper alignment */
  50         if ((magic = *(tnf_uint32_t *)base) == TNF_MAGIC)
  51                 native = 1;     /* same endian */
  52         else if (magic == TNF_MAGIC_1)
  53                 native = 0;     /* other endian */
  54         else
  55                 return (TNF_ERR_NOTTNF);
  56
  57         /*
  58          * Allocate TNF struct, initialize members
  59          */
  60
  61         if ((tnf = (TNF*)calloc(1, sizeof (*tnf))) == (TNF*)NULL)
  62                 return (TNF_ERR_ALLOCFAIL);
  63
  64         tnf->file_magic         = magic;
  65         tnf->file_native        = native;
  66         tnf->file_start         = base;
  67         tnf->file_size          = size;
  68         tnf->file_end           = base + size;
  69
  70         /*
  71          * Examine file header
  72          */
  73
  74         /* LINTED pointer cast may result in improper alignment */
  75         fhdr = (tnf_ref32_t *)(base + sizeof (magic)); /* second word */
  76         tnf->file_header = fhdr;
  77
  78         /* Block size */
  79         p = _tnf_get_slot_named(tnf, fhdr, TNF_N_BLOCK_SIZE);
  80         /* LINTED pointer cast may result in improper alignment */
  81         tnf->block_size = _GET_UINT32(tnf, (tnf_uint32_t *)p);
  82
  83         /* Directory size */
  84         p = _tnf_get_slot_named(tnf, fhdr, TNF_N_DIRECTORY_SIZE);
  85         /* LINTED pointer cast may result in improper alignment */
  86         tnf->directory_size = _GET_UINT32(tnf, (tnf_uint32_t *)p);
  87
  88         /* Block count */
  89         p = _tnf_get_slot_named(tnf, fhdr, TNF_N_BLOCK_COUNT);
  90         /* LINTED pointer cast may result in improper alignment */
  91         tnf->block_count = _GET_UINT32(tnf, (tnf_uint32_t *)p);
  92         /*
  93          * This member tracks data block count, not total block count
  94          * (unlike the TNF file header).   Discount directory blocks.
  95          */
  96         tnf->block_count -= tnf->directory_size / tnf->block_size;
  97
  98         /*
  99          * 1196886: Clients may supply file_size information obtained
 100          * by fstat() which is incorrect.  Check it now and revise
 101          * downwards if we have to.
 102          */
 103         tmpsz = tnf->directory_size + tnf->block_count * tnf->block_size;
 104         if (tmpsz != size) {
 105                 if (tmpsz > size)
 106                         /* missing data? */
 107                         return (TNF_ERR_BADTNF);
 108                 else {
 109                         tnf->file_size = tmpsz;
 110                         tnf->file_end = base + tmpsz;
 111                 }
 112         }
 113
 114         /* Calculate block shift */
 115         tmpsz = 1;
 116         while (tmpsz != tnf->block_size) {
 117                 tmpsz <<= 1;
 118                 tnf->block_shift++;
 119         }
 120
 121         /* Calculate block mask */
 122         tnf->block_mask = ~(tnf->block_size - 1);
 123
 124         /* Generation shift */
 125         p = _tnf_get_slot_named(tnf, fhdr, TNF_N_FILE_LOGICAL_SIZE);
 126         /* LINTED pointer cast may result in improper alignment */
 127         tnf->generation_shift   = _GET_UINT32(tnf, (tnf_uint32_t *)p);
 128
 129         /* Calculate the address mask */
 130         /*
 131          * Following lint complaint is unwarranted, probably an
 132          * uninitialized variable in lint or something ...
 133          */
 134         /* LINTED constant truncated by assignment */
 135         tnf->address_mask = 0xffffffff;
 136         tnf->address_mask <<= tnf->generation_shift;
 137         tnf->address_mask = ~(tnf->address_mask);
 138
 139
 140         /*
 141          * Examine first block header in data area
 142          */
 143
 144         tnf->data_start = tnf->file_start + tnf->directory_size;
 145         /* LINTED pointer cast may result in improper alignment */
 146         bhdr = (tnf_ref32_t *)tnf->data_start;
 147
 148         /* Block generation offset */
 149         genp = _tnf_get_slot_named(tnf, bhdr, TNF_N_GENERATION);
 150         tnf->block_generation_offset = genp - (caddr_t)bhdr;
 151
 152         /* Block bytes valid offset */
 153         bvp = _tnf_get_slot_named(tnf, bhdr, TNF_N_BYTES_VALID);
 154         tnf->block_bytes_valid_offset = bvp - (caddr_t)bhdr;
 155
 156         /*
 157          * Bootstrap taginfo system and cache important taginfo
 158          */
 159
 160         if ((err = _tnf_init_tags(tnf)) != TNF_ERR_NONE)
 161                 return (err);
 162
 163         tnf->file_header_info   = _tnf_get_info(tnf, _tnf_get_tag(tnf, fhdr));
 164         tnf->block_header_info  = _tnf_get_info(tnf, _tnf_get_tag(tnf, bhdr));
 165
 166         /*
 167          * Return TNF handle and error status
 168          */
 169
 170         *tnfret = tnf;
 171         return (TNF_ERR_NONE);
 172 }
 173
 174 /*
 175  * Terminate a reader session
 176  */
 177
 178 tnf_errcode_t
 179 tnf_reader_end(TNF *tnf)
 180 {
 181         tnf_errcode_t   err;
 182
 183         /* Deallocate all taginfo */
 184         if ((err = _tnf_fini_tags(tnf)) != TNF_ERR_NONE)
 185                 return (err);
 186
 187         /* Deallocate TNF */
 188         free(tnf);
 189
 190         return (TNF_ERR_NONE);
 191 }