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      1 /* Create new, empty section data.
      2    Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
      3    This file is part of Red Hat elfutils.
      4    Contributed by Ulrich Drepper <drepper (at) redhat.com>, 1998.
      5 
      6    Red Hat elfutils is free software; you can redistribute it and/or modify
      7    it under the terms of the GNU General Public License as published by the
      8    Free Software Foundation; version 2 of the License.
      9 
     10    Red Hat elfutils is distributed in the hope that it will be useful, but
     11    WITHOUT ANY WARRANTY; without even the implied warranty of
     12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13    General Public License for more details.
     14 
     15    You should have received a copy of the GNU General Public License along
     16    with Red Hat elfutils; if not, write to the Free Software Foundation,
     17    Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
     18 
     19    In addition, as a special exception, Red Hat, Inc. gives You the
     20    additional right to link the code of Red Hat elfutils with code licensed
     21    under any Open Source Initiative certified open source license
     22    (http://www.opensource.org/licenses/index.php) which requires the
     23    distribution of source code with any binary distribution and to
     24    distribute linked combinations of the two.  Non-GPL Code permitted under
     25    this exception must only link to the code of Red Hat elfutils through
     26    those well defined interfaces identified in the file named EXCEPTION
     27    found in the source code files (the "Approved Interfaces").  The files
     28    of Non-GPL Code may instantiate templates or use macros or inline
     29    functions from the Approved Interfaces without causing the resulting
     30    work to be covered by the GNU General Public License.  Only Red Hat,
     31    Inc. may make changes or additions to the list of Approved Interfaces.
     32    Red Hat's grant of this exception is conditioned upon your not adding
     33    any new exceptions.  If you wish to add a new Approved Interface or
     34    exception, please contact Red Hat.  You must obey the GNU General Public
     35    License in all respects for all of the Red Hat elfutils code and other
     36    code used in conjunction with Red Hat elfutils except the Non-GPL Code
     37    covered by this exception.  If you modify this file, you may extend this
     38    exception to your version of the file, but you are not obligated to do
     39    so.  If you do not wish to provide this exception without modification,
     40    you must delete this exception statement from your version and license
     41    this file solely under the GPL without exception.
     42 
     43    Red Hat elfutils is an included package of the Open Invention Network.
     44    An included package of the Open Invention Network is a package for which
     45    Open Invention Network licensees cross-license their patents.  No patent
     46    license is granted, either expressly or impliedly, by designation as an
     47    included package.  Should you wish to participate in the Open Invention
     48    Network licensing program, please visit www.openinventionnetwork.com
     49    <http://www.openinventionnetwork.com>.  */
     50 
     51 #ifdef HAVE_CONFIG_H
     52 # include <config.h>
     53 #endif
     54 
     55 #include <stddef.h>
     56 #include <stdlib.h>
     57 
     58 #include "libelfP.h"
     59 
     60 
     61 Elf_Data *
     62 elf_newdata (Elf_Scn *scn)
     63 {
     64   Elf_Data_List *result = NULL;
     65 
     66   if (scn == NULL)
     67     return NULL;
     68 
     69   if (unlikely (scn->index == 0))
     70     {
     71       /* It is not allowed to add something to the 0th section.  */
     72       __libelf_seterrno (ELF_E_NOT_NUL_SECTION);
     73       return NULL;
     74     }
     75 
     76   if (scn->elf->class == ELFCLASS32
     77       || (offsetof (struct Elf, state.elf32.ehdr)
     78 	  == offsetof (struct Elf, state.elf64.ehdr))
     79       ? scn->elf->state.elf32.ehdr == NULL
     80       : scn->elf->state.elf64.ehdr == NULL)
     81     {
     82       __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
     83       return NULL;
     84     }
     85 
     86   rwlock_wrlock (scn->elf->lock);
     87 
     88   if (scn->data_read && scn->data_list_rear == NULL)
     89     {
     90       /* This means the section was created by the user and this is the
     91 	 first data.  */
     92       result = &scn->data_list;
     93       result->flags = ELF_F_DIRTY;
     94     }
     95   else
     96     {
     97       /* Create a new, empty data descriptor.  */
     98       result = (Elf_Data_List *) calloc (1, sizeof (Elf_Data_List));
     99       if (result == NULL)
    100 	{
    101 	  __libelf_seterrno (ELF_E_NOMEM);
    102 	  goto out;
    103 	}
    104 
    105       result->flags = ELF_F_DIRTY | ELF_F_MALLOCED;
    106 
    107       if (scn->data_list_rear == NULL)
    108 	/* We create new data without reading/converting the data from the
    109 	   file.  That is fine but we have to remember this.  */
    110 	scn->data_list_rear = &scn->data_list;
    111     }
    112 
    113   /* Set the predefined values.  */
    114   result->data.d.d_version = __libelf_version;
    115 
    116   result->data.s = scn;
    117 
    118   /* Add to the end of the list.  */
    119   if (scn->data_list_rear != NULL)
    120     scn->data_list_rear->next = result;
    121 
    122   scn->data_list_rear = result;
    123 
    124  out:
    125   rwlock_unlock (scn->elf->lock);
    126 
    127   /* Please note that the following is thread safe and is also defined
    128      for RESULT == NULL since it still return NULL.  */
    129   return &result->data.d;
    130 }
    131