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/*

 * Copyright (c) 2008 Jiri Svoboda

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup rtld rtld

 * @brief

 * @{

 */

/**

 * @file

 */

#include <stdio.h>

#include <stdlib.h>

#include <arch.h>

#include <elf_dyn.h>

#include <symbol.h>

#include <rtld.h>

void module_process_pre_arch(module_t *m)

{

    elf_symbol_t *sym_table;

    elf_symbol_t *sym_def;

    elf_symbol_t *sym;

    uint32_t gotsym;

    uint32_t *got;

    char *str_tab;

    int i;

    uint32_t sym_addr;

    module_t *dest;

    got = (uint32_t *) m->dyn.plt_got;

    sym_table = m->dyn.sym_tab;

    str_tab = m->dyn.str_tab;

    gotsym = m->dyn.arch.gotsym;

    DPRINTF("** Relocate GOT entries **\n");

    DPRINTF("MIPS base = 0x%x\n", m->dyn.arch.base);

    /*

     * Local entries.

     */

    for (i = 0; i < gotsym; i++) {

        /* FIXME: really subtract MIPS base? */

        got[i] += m->bias - m->dyn.arch.base;

    }

    DPRINTF("sym_ent = %d, gotsym = %d\n", m->dyn.arch.sym_no, gotsym);

    /*

     * Global entries.

     */

    for (i = gotsym; i < m->dyn.arch.sym_no; i++) {

        DPRINTF("relocate GOT entry %d\n", i);

//      getchar();

        sym = &sym_table[i];

        if (ELF32_R_TYPE(sym->st_info) == STT_FUNC) {

            if (sym->st_shndx == SHN_UNDEF) {

                if (sym->st_value == 0) {

                    /* 1 */

                } else {

                    if (got[i] == sym->st_value) {

                        /* 2 */

                        DPRINTF("(2)\n");

                        got[i] += m->bias - m->dyn.arch.base;

                        continue;

                    } else {

                        /* 3 */

                        DPRINTF("(3)\n");

                        got[i] = sym->st_value + m->bias - m->dyn.arch.base;

                        continue;

                    }

                }

            } else {

                /* 2 */

                DPRINTF("(2)\n");

                got[i] += m->bias - m->dyn.arch.base;

                continue;

            }

        } else {

            if (sym->st_shndx == SHN_UNDEF ||

                sym->st_shndx == SHN_COMMON) {

                /* 1 */

            } else {

                /* 1 */

            }

        }

        DPRINTF("(1) symbol name='%s'\n", str_tab + sym->st_name);

        sym_def = symbol_def_find(str_tab + sym->st_name, m, &dest);

        if (sym_def) {

            sym_addr = symbol_get_addr(sym_def, dest);

            DPRINTF("symbol definition found, addr=0x%x\n", sym_addr);

        } else {

            DPRINTF("symbol definition not found\n");

            continue;

        }

        DPRINTF("write 0x%x at 0x%x\n", sym_addr, (uint32_t) &got[i]);

//      getchar();

        got[i] = sym_addr;

    }

    DPRINTF("** Done **\n");

}

/**

 * Process (fixup) all relocations in a relocation table.

 */

void rel_table_process(module_t *m, elf_rel_t *rt, size_t rt_size)

{

    int i;

    size_t rt_entries;

    size_t r_offset;

    elf_word r_info;

    unsigned rel_type;

    elf_word sym_idx;

    uintptr_t sym_addr;

    elf_symbol_t *sym_table;

    elf_symbol_t *sym;

    uint32_t *r_ptr;

    uint16_t *r_ptr16;

    char *str_tab;

    elf_symbol_t *sym_def;

    module_t *dest;

    uint32_t *got;

    uint32_t gotsym;

    uint32_t ea;

    DPRINTF("parse relocation table\n");

    sym_table = m->dyn.sym_tab;

    rt_entries = rt_size / sizeof(elf_rela_t);

    str_tab = m->dyn.str_tab;

    got = (uint32_t *) m->dyn.plt_got;

    gotsym = m->dyn.arch.gotsym;

    DPRINTF("got=0x%lx, gotsym=%d\n", (uintptr_t) got, gotsym);

    DPRINTF("address: 0x%x, entries: %d\n", (uintptr_t)rt, rt_entries);

    for (i = 0; i < rt_entries; ++i) {

        DPRINTF("symbol %d: ", i);

        r_offset = rt[i].r_offset;

        r_info = rt[i].r_info;

        sym_idx = ELF32_R_SYM(r_info);

        sym = &sym_table[sym_idx];

        DPRINTF("name '%s', value 0x%x, size 0x%x\n",

            str_tab + sym->st_name,

            sym->st_value,

            sym->st_size);

        rel_type = ELF32_R_TYPE(r_info);

        r_ptr = (uint32_t *)(r_offset + m->bias);

        r_ptr16 = (uint16_t *)(r_offset + m->bias);

        if (sym->st_name != 0) {

            DPRINTF("rel_type: %x, rel_offset: 0x%x\n", rel_type, r_offset);

            DPRINTF("dest name: '%s'\n", dest->dyn.soname);

            DPRINTF("dest bias: 0x%x\n", dest->bias);

            if (sym_def) {

                sym_addr = symbol_get_addr(sym_def, dest);

                DPRINTF("symbol definition found, addr=0x%x\n", sym_addr);

            } else {

                DPRINTF("symbol definition not found\n");

                continue;

            }

        }

        DPRINTF("switch(%u)\n", rel_type);

        switch (rel_type) {

        case R_MIPS_NONE:

            DPRINTF("Ignoring R_MIPS_NONE\n");

            break;

        case R_MIPS_REL32:

            DPRINTF("fixup R_MIPS_REL32 (r - ea + s)\n");

            if (sym_idx < gotsym)

                ea = sym_addr;

            else

                ea = got[sym_idx];

            *r_ptr += sym_addr - ea;

            DPRINTF("p = 0x%x, val := 0x%x\n", (uint32_t) r_ptr,

                *r_ptr);

//          getchar();

            break;

        /* No other non-TLS relocation types should appear. */

        case R_MIPS_TLS_DTPMOD32:

            /*

             * We can ignore this as long as the only module

             * with TLS variables is libc.so.

             */

            DPRINTF("Ignoring R_MIPS_DTPMOD32\n");

            break;

        default:

            printf("Error: Unknown relocation type %d.\n",

                rel_type);

            exit(1);

            break;

        }

    }

    printf("relocation done\n");

}

void rela_table_process(module_t *m, elf_rela_t *rt, size_t rt_size)

{

    /* Unused */

    (void)m; (void)rt; (void)rt_size;

}

/** @}

 */