htelfrel.cc

Go to the documentation of this file.

/* 
 *      HT Editor
 *      htelfrel.cc
 *
 *      Copyright (C) 1999-2002 Stefan Weyergraf (stefan@weyergraf.de)
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License version 2 as
 *      published by the Free Software Foundation.
 *
 *      This program 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 this program; if not, write to the Free Software
 *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "elfstruc.h"
#include "htatom.h"
#include "htelf.h"
#include "htelfrel.h"
#include "httag.h"
#include "formats.h"
#include "snprintf.h"

#include <stdlib.h>

static int_hash elf_r_386_type[] =
{
        {ELF_R_386_NONE,                "ELF_R_386_NONE"},
        {ELF_R_386_32,                  "ELF_R_386_32"},
        {ELF_R_386_PC32,                "ELF_R_386_PC32"},
        {ELF_R_386_GOT32,               "ELF_R_386_GOT32"},
        {ELF_R_386_PLT32,               "ELF_R_386_PLT32"},
        {ELF_R_386_COPY,                "ELF_R_386_COPY"},
        {ELF_R_386_GLOB_DAT,    "ELF_R_386_GLOB_DAT"},
        {ELF_R_386_JMP_SLOT,    "ELF_R_386_JMP_SLOT"},
        {ELF_R_386_RELATIVE,    "ELF_R_386_RELATIVE"},
        {ELF_R_386_GOTOFF,              "ELF_R_386_GOTOFF"},
        {ELF_R_386_GOTPC,               "ELF_R_386_GOTPC"},
        {0, 0}
};

static ht_view *htelfreloctable_init(bounds *b, ht_streamfile *file, ht_format_group *group)
{
        ht_elf_shared_data *elf_shared=(ht_elf_shared_data *)group->get_shared_data();

        if ((elf_shared->ident.e_ident[ELF_EI_CLASS]!=ELFCLASS32) ||
        (elf_shared->ident.e_ident[ELF_EI_DATA]!=ELFDATA2LSB) ||
        (elf_shared->header32.e_machine!=ELF_EM_386)) return NULL;
        
        UINT skip = elf_shared->reloctables;
        UINT reloctab_shidx = ELF_SHN_UNDEF;
        UINT reloctab_sh_type = ELF_SHT_NULL;
        for (UINT i=1; i<elf_shared->sheaders.count; i++) {
                if ((elf_shared->sheaders.sheaders32[i].sh_type==ELF_SHT_REL) || (elf_shared->sheaders.sheaders32[i].sh_type==ELF_SHT_RELA)) {
                        if (!skip--) {
                                reloctab_sh_type=elf_shared->sheaders.sheaders32[i].sh_type;
                                reloctab_shidx=i;
                                break;
                        }
                }
        }
        if (!isValidELFSectionIdx(elf_shared, reloctab_shidx)) return NULL;

        FILEOFS h=elf_shared->sheaders.sheaders32[reloctab_shidx].sh_offset;
        
        /* section index of associated symbol table */
        int si_symbol=elf_shared->sheaders.sheaders32[reloctab_shidx].sh_link;
        
        /* section index of section to be relocated */
        int si_dest=elf_shared->sheaders.sheaders32[reloctab_shidx].sh_info;

        char *reloctab_name;
        if (!isValidELFSectionIdx(elf_shared, elf_shared->header32.e_shstrndx)
        || file->seek(elf_shared->sheaders.sheaders32[elf_shared->header32.
        e_shstrndx].sh_offset+elf_shared->sheaders.sheaders32[reloctab_shidx].sh_name)
        || !((reloctab_name=fgetstrz(file))))
                reloctab_name = "?";
        char desc[128];
        ht_snprintf(desc, sizeof desc, DESC_ELF_RELOCTAB, reloctab_name, reloctab_shidx);
        free(reloctab_name);
        
        ht_uformat_viewer *v=new ht_uformat_viewer();
        v->init(b, desc, VC_EDIT, file, group);
        
        ht_mask_sub *m=new ht_mask_sub();
        m->init(file, 0);
        
        register_atom(ATOM_ELF_R_386_TYPE, elf_r_386_type);

        char t[256];    /* FIXME: possible buffer overflow ! */
        ht_snprintf(t, sizeof t, "* ELF relocation table at offset %08x, relocates section %d, symtab %d", h, si_dest, si_symbol);

        m->add_mask(t);

        bool elf_bigendian = (elf_shared->ident.e_ident[ELF_EI_DATA] == ELFDATA2MSB);

        switch (reloctab_sh_type) {
                case ELF_SHT_REL: {
                        m->add_mask("destofs  symidx type");
                        UINT relnum=elf_shared->sheaders.sheaders32[reloctab_shidx].sh_size / sizeof (ELF_REL32);
                        for (UINT i=0; i<relnum; i++) {
                                char *tt=t;
                                /* dest offset */
                                tt=tag_make_edit_dword(tt, h+i*sizeof (ELF_REL32), elf_bigendian ? tag_endian_big : tag_endian_little);
                                *tt++=' ';
                                /* symbol (table idx) */
                                tt=tag_make_edit_word(tt, h+i*sizeof (ELF_REL32)+4+1, elf_bigendian ? tag_endian_big : tag_endian_little);
                                *tt++=' ';
                                *tt++=' ';
                                *tt++=' ';
                                /* type */
                                tt=tag_make_edit_byte(tt, h+i*sizeof (ELF_REL32)+4);
                                *tt++='(';
                                /* type */
                                tt=tag_make_desc_byte(tt, h+i*sizeof (ELF_REL32)+4, ATOM_ELF_R_386_TYPE);
                                *tt++=')';
                                *tt=0;
                                m->add_mask(t);
                        }
                        break;
                }
                case ELF_SHT_RELA: {
                        m->add_mask("destofs  symidx addend   type");
                        UINT relnum=elf_shared->sheaders.sheaders32[reloctab_shidx].sh_size / sizeof (ELF_RELA32);
                        for (UINT i=0; i<relnum; i++) {
                                char *tt=t;
                                /* dest offset */
                                tt=tag_make_edit_dword(tt, h+i*sizeof (ELF_RELA32), elf_bigendian ? tag_endian_big : tag_endian_little);
                                *tt++=' ';
                                /* symbol (table idx) */
                                tt=tag_make_edit_word(tt, h+i*sizeof (ELF_RELA32)+4+1, elf_bigendian ? tag_endian_big : tag_endian_little);
                                *tt++=' ';
                                *tt++=' ';
                                *tt++=' ';
                                /* addend */
                                tt=tag_make_edit_dword(tt, h+i*sizeof (ELF_RELA32)+4+4, elf_bigendian ? tag_endian_big : tag_endian_little);
                                *tt++=' ';
                                /* type */
                                tt=tag_make_edit_byte(tt, h+i*sizeof (ELF_RELA32)+4);
                                *tt++='(';
                                /* type */
                                tt=tag_make_desc_byte(tt, h+i*sizeof (ELF_RELA32)+4, ATOM_ELF_R_386_TYPE);
                                *tt++=')';
                                *tt=0;
                                m->add_mask(t);
                        }
                        break;
                }
        }
        
        v->insertsub(m);
        return v;
}

format_viewer_if htelfreloctable_if = {
        htelfreloctable_init,
        0
};

---