external/bsd/elftoolchain/dist/libelf/libelf_xlate.c

   1 /*      $NetBSD: libelf_xlate.c,v 1.2 2014/03/09 16:58:04 christos Exp $        */
   2
   3 /*-
   4  * Copyright (c) 2006,2008 Joseph Koshy
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #if HAVE_NBTOOL_CONFIG_H
  30 # include "nbtool_config.h"
  31 #endif
  32
  33 #include <sys/cdefs.h>
  34
  35 #include <assert.h>
  36 #include <libelf.h>
  37
  38 #include "_libelf.h"
  39
  40 __RCSID("$NetBSD: libelf_xlate.c,v 1.2 2014/03/09 16:58:04 christos Exp $");
  41 ELFTC_VCSID("Id: libelf_xlate.c 2225 2011-11-26 18:55:54Z jkoshy ");
  42
  43 /*
  44  * Translate to/from the file representation of ELF objects.
  45  *
  46  * Translation could potentially involve the following
  47  * transformations:
  48  *
  49  * - an endianness conversion,
  50  * - a change of layout, as the file representation of ELF objects
  51  *   can differ from their in-memory representation.
  52  * - a change in representation due to a layout version change.
  53  */
  54
  55 Elf_Data *
  56 _libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding,
  57     int elfclass, int direction)
  58 {
  59         int byteswap;
  60         size_t cnt, dsz, fsz, msz;
  61         uintptr_t sb, se, db, de;
  62
  63         if (encoding == ELFDATANONE)
  64                 encoding = _libelf_host_byteorder();
  65
  66         if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) ||
  67             dst == NULL || src == NULL || dst == src)   {
  68                 LIBELF_SET_ERROR(ARGUMENT, 0);
  69                 return (NULL);
  70         }
  71
  72         assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
  73         assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY);
  74
  75         if (dst->d_version != src->d_version) {
  76                 LIBELF_SET_ERROR(UNIMPL, 0);
  77                 return (NULL);
  78         }
  79
  80         if  (src->d_buf == NULL || dst->d_buf == NULL) {
  81                 LIBELF_SET_ERROR(DATA, 0);
  82                 return (NULL);
  83         }
  84
  85         if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) {
  86                 LIBELF_SET_ERROR(DATA, 0);
  87                 return (NULL);
  88         }
  89
  90         if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
  91             (src->d_type, (size_t) 1, src->d_version)) == 0)
  92                 return (NULL);
  93
  94         msz = _libelf_msize(src->d_type, elfclass, src->d_version);
  95
  96         assert(msz > 0);
  97
  98         if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) {
  99                 LIBELF_SET_ERROR(DATA, 0);
 100                 return (NULL);
 101         }
 102
 103         /*
 104          * Determine the number of objects that need to be converted, and
 105          * the space required for the converted objects in the destination
 106          * buffer.
 107          */
 108         if (direction == ELF_TOMEMORY) {
 109                 cnt = src->d_size / fsz;
 110                 dsz = cnt * msz;
 111         } else {
 112                 cnt = src->d_size / msz;
 113                 dsz = cnt * fsz;
 114         }
 115
 116         if (dst->d_size  <  dsz) {
 117                 LIBELF_SET_ERROR(DATA, 0);
 118                 return (NULL);
 119         }
 120
 121         sb = (uintptr_t) src->d_buf;
 122         se = sb + src->d_size;
 123         db = (uintptr_t) dst->d_buf;
 124         de = db + dst->d_size;
 125
 126         /*
 127          * Check for overlapping buffers.  Note that db == sb is
 128          * allowed.
 129          */
 130         if (db != sb && de > sb && se > db) {
 131                 LIBELF_SET_ERROR(DATA, 0);
 132                 return (NULL);
 133         }
 134
 135         if ((direction == ELF_TOMEMORY ? db : sb) %
 136             _libelf_malign(src->d_type, elfclass)) {
 137                 LIBELF_SET_ERROR(DATA, 0);
 138                 return (NULL);
 139         }
 140
 141         dst->d_type = src->d_type;
 142         dst->d_size = dsz;
 143
 144         byteswap = encoding != _libelf_host_byteorder();
 145
 146         if (src->d_size == 0 ||
 147             (db == sb && !byteswap && fsz == msz))
 148                 return (dst);   /* nothing more to do */
 149
 150         if (!(_libelf_get_translator(src->d_type, direction, elfclass))
 151             (dst->d_buf, dsz, src->d_buf, cnt, byteswap)) {
 152                 LIBELF_SET_ERROR(DATA, 0);
 153                 return (NULL);
 154         }
 155
 156         return (dst);
 157 }