libelf/elf32_xlatetof.c

   1 /* Convert from memory to file representation.
   2    Copyright (C) 1998, 1999, 2000, 2002, 2015 Red Hat, Inc.
   3    This file is part of elfutils.
   4    Written by Ulrich Drepper <drepper@redhat.com>, 1998.
   5
   6    This file is free software; you can redistribute it and/or modify
   7    it under the terms of either
   8
   9      * the GNU Lesser General Public License as published by the Free
  10        Software Foundation; either version 3 of the License, or (at
  11        your option) any later version
  12
  13    or
  14
  15      * the GNU General Public License as published by the Free
  16        Software Foundation; either version 2 of the License, or (at
  17        your option) any later version
  18
  19    or both in parallel, as here.
  20
  21    elfutils is distributed in the hope that it will be useful, but
  22    WITHOUT ANY WARRANTY; without even the implied warranty of
  23    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  24    General Public License for more details.
  25
  26    You should have received copies of the GNU General Public License and
  27    the GNU Lesser General Public License along with this program.  If
  28    not, see <http://www.gnu.org/licenses/>.  */
  29
  30 #ifdef HAVE_CONFIG_H
  31 # include <config.h>
  32 #endif
  33
  34 #include <assert.h>
  35 #include <string.h>
  36
  37 #include "libelfP.h"
  38
  39 #ifndef LIBELFBITS
  40 # define LIBELFBITS     32
  41 #endif
  42
  43
  44 Elf_Data *
  45 elfw2(LIBELFBITS, xlatetof) (Elf_Data *dest, const Elf_Data *src,
  46                              unsigned int encode)
  47 {
  48   /* First test whether the input data is really suitable for this
  49      type.  This means, whether there is an integer number of records.
  50      Note that for this implementation the memory and file size of the
  51      data types are identical.  */
  52   size_t recsize = __libelf_type_sizes[ELFW(ELFCLASS,LIBELFBITS) - 1][src->d_type];
  53
  54   if (src->d_size % recsize != 0)
  55     {
  56       __libelf_seterrno (ELF_E_INVALID_DATA);
  57       return NULL;
  58     }
  59
  60   /* Next see whether the converted data fits in the output buffer.  */
  61   if (src->d_size > dest->d_size)
  62     {
  63       __libelf_seterrno (ELF_E_DEST_SIZE);
  64       return NULL;
  65     }
  66
  67   /* Test the encode parameter.  */
  68   if (encode != ELFDATA2LSB && encode != ELFDATA2MSB)
  69     {
  70       __libelf_seterrno (ELF_E_INVALID_ENCODING);
  71       return NULL;
  72     }
  73
  74   /* Determine the translation function to use.
  75
  76      At this point we make an assumption which is valid for all
  77      existing implementations so far: the memory and file sizes are
  78      the same.  This has very important consequences:
  79      a) The requirement that the source and destination buffer can
  80         overlap can easily be fulfilled.
  81      b) We need only one function to convert from and memory to file
  82         and vice versa since the function only has to copy and/or
  83         change the byte order.
  84   */
  85   if ((BYTE_ORDER == LITTLE_ENDIAN && encode == ELFDATA2LSB)
  86       || (BYTE_ORDER == BIG_ENDIAN && encode == ELFDATA2MSB))
  87     {
  88       /* We simply have to copy since the byte order is the same.  */
  89       if (src->d_buf != dest->d_buf)
  90         memmove (dest->d_buf, src->d_buf, src->d_size);
  91     }
  92   else
  93     {
  94       xfct_t fctp;
  95       fctp = __elf_xfctstom[ELFW(ELFCLASS, LIBELFBITS) - 1][src->d_type];
  96
  97       /* Do the real work.  */
  98       (*fctp) (dest->d_buf, src->d_buf, src->d_size, 1);
  99     }
 100
 101   /* Now set the real destination type and length since the operation was
 102      successful.  */
 103   dest->d_type = src->d_type;
 104   dest->d_size = src->d_size;
 105
 106   return dest;
 107 }
 108 INTDEF(elfw2(LIBELFBITS, xlatetof))