/* OpenIDA - Outil d'analyse de fichiers binaires
 * e_elf.c - support du format ELF
 *
 * Copyright (C) 2008 Cyrille Bagard
 *
 *  This file is part of OpenIDA.
 *
 *  OpenIDA is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  OpenIDA is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "e_elf.h"


#include <malloc.h>
#include <string.h>


#include "elf-int.h"
#include "section.h"
#include "symbol.h"




/******************************************************************************
*                                                                             *
*  Paramètres  : content = contenu binaire à parcourir.                       *
*                length  = taille du contenu en question.                     *
*                                                                             *
*  Description : Prend en charge un nouvel ELF.                               *
*                                                                             *
*  Retour      : Adresse de la structure mise en place ou NULL en cas d'échec.*
*                                                                             *
*  Remarques   : -                                                            *
*                                                                             *
******************************************************************************/

elf_format *load_elf(const uint8_t *content, off_t length)
{
    elf_format *result;                     /* Structure à retourner       */
    bool test;                              /* Bilan d'une initialisation  */

    result = (elf_format *)calloc(1, sizeof(elf_format));

    EXE_FORMAT(result)->content = content;
    EXE_FORMAT(result)->length = length;

    EXE_FORMAT(result)->find_section = (find_section_fc)find_elf_section;
    EXE_FORMAT(result)->get_symbols = (get_symbols_fc)get_elf_symbols;
    EXE_FORMAT(result)->resolve_symbol = (resolve_symbol_fc)resolve_elf_symbol;

    memcpy(&result->header, content, sizeof(Elf32_Ehdr));


    test = read_elf_section_names(result);

    printf("ok ? %d\n", test);

    test = load_elf_symbols(result);

    printf("ok ? %d\n", test);


    return result;

}


/******************************************************************************
*                                                                             *
*  Paramètres  : format  = informations chargées à consulter.                 *
*                labels  = liste des commentaires à insérer. [OUT]            *
*                types   = type des symboles listés. [OUT]                    *
*                offsets = liste des indices des commentaires. [OUT]          *
*                                                                             *
*  Description : Récupère tous les symboles présents dans le contenu binaire. *
*                                                                             *
*  Retour      : Nombre d'éléments mis en place.                              *
*                                                                             *
*  Remarques   : -                                                            *
*                                                                             *
******************************************************************************/

size_t get_elf_symbols(const elf_format *format, char ***labels, SymbolType **types, uint64_t **offsets)
{
    size_t result;                          /* Quantité à retourner        */
    size_t i;                               /* Boucle de parcours          */

    result = format->sym_count;

    *labels = (char **)calloc(result, sizeof(char *));
    *types = (SymbolType *)calloc(result, sizeof(SymbolType));
    *offsets = (uint64_t *)calloc(result, sizeof(uint64_t));

    for (i = 0; i < format->sym_count; i++)
    {
        (*labels)[i] = strdup(format->symbols[i].name);
        (*types)[i] = STP_SECTION;
        (*offsets)[i] = format->symbols[i].address;
    }

    return result;

}


/******************************************************************************
*                                                                             *
*  Paramètres  : format = informations chargées à consulter.                  *
*                label  = étiquette du symbole si trouvé. [OUT]               *
*                type   = type du symbole trouvé. [OUT]                       *
*                offset = adresse à cibler, puis décallage final. [OUT]       *
*                                                                             *
*  Description : Recherche le symbole correspondant à une adresse.            *
*                                                                             *
*  Retour      : true si l'opération a été un succès, false sinon.            *
*                                                                             *
*  Remarques   : -                                                            *
*                                                                             *
******************************************************************************/

bool resolve_elf_symbol(const elf_format *format, char **label, SymbolType *type, uint64_t *offset)
{
    bool result;                            /* Bilan à retourner           */
    size_t best_index;                      /* Meilleur symbole trouvé     */
    uint64_t best_addr;                     /* Meilleure adresse trouvée   */
    size_t i;                               /* Boucle de parcours          */

    best_addr = UINT64_MAX;

    for (i = 0; i < format->sym_count; i++)
        if (format->symbols[i].address <= *offset && (*offset - format->symbols[i].address) < best_addr)
        {
            best_index = i;
            best_addr = *offset - format->symbols[i].address;
        }

    result = (best_addr != UINT64_MAX);

    if (result)
    {
        *label = strdup(format->symbols[best_index].name);
        *type = STP_SECTION;
        *offset -= format->symbols[best_index].address;
    }

    return result;

}