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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 <elf_dyn.h>

#include <rtld.h>

#include <pcb.h>

void __main(void);

void __io_init(void);

void __exit(void);

static void kputint(unsigned i)

{

    unsigned dummy;

    asm volatile (

        "movl $31, %%eax;"

        "int $0x30"

        : "=d" (dummy) /* output - %edx clobbered */

        : "d" (i) /* input */

        : "%eax","%ecx" /* all scratch registers clobbered */

    ); 

}

void __bootstrap(void)

{

    unsigned bias;

    unsigned *got;

    elf_dyn_t *dynamic;

    void *dptr;

    unsigned dval;

    int i;

    size_t rel_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_rel_t *rel_table;

    elf_rel_t *jmp_rel_table;

    size_t jmp_rel_entries;

    pcb_t *pcb;

    pcb = __pcb_get();

    /* The program loader (iloader) kindly provided us with these */

    dynamic = pcb->rtld_dynamic;

    bias = pcb->rtld_bias;

/*

asm volatile (

    // Calculate the bias into %0

    // Generates "fake" R_386_RELATIVE run-time relocation

"   call .L0;"

".L0:   pop %0;"

"   subl $.L0, %0;"

    // Calculate run-time address of _DYNAMIC into %1

    // Generates "fake" R_386_RELATIVE run-time relocation

"   movl $_DYNAMIC, %1;"    // Again, at link time 0-based VMA gets in

"   addl %0, %1;"       // Add bias to compute run-time address

: "=r" (bias), "=r" (dynamic)

);

*/

    kputint(bias);

    kputint((unsigned)dynamic);

    /* parse DYNAMIC */

    got = 0;

    sym_table = 0;

    rel_table = 0;

    rel_entries = 0;

    jmp_rel_table = 0;

    jmp_rel_entries = 0;

    i = 0;

    while (dynamic[i].d_tag != 0) {

        dptr = (void *)(dynamic[i].d_un.d_val + bias);

        dval = dynamic[i].d_un.d_val;

        switch (dynamic[i].d_tag) {

        case DT_PLTRELSZ: jmp_rel_entries = dval/8; break;

        case DT_JMPREL: jmp_rel_table = dptr; break;

        case DT_PLTGOT:

            /* GOT address */

            got = dptr; break;

        case DT_SYMTAB: sym_table = dptr; break;

        case DT_REL: rel_table = dptr; break;

        case DT_RELSZ: rel_entries = dval / 8; break;

        default: break;

        }

        ++i;

    }

    kputint(1);

    kputint((unsigned)sym_table);

    kputint((unsigned)rel_table);

    kputint((unsigned)rel_entries);

    /* Now relocate all our dynsyms */

    kputint(-1);

    for (i=0; i<rel_entries; i++) {

        kputint(i);

        r_offset = rel_table[i].r_offset;

        r_info = rel_table[i].r_info;

        rel_type = ELF32_R_TYPE(r_info);

        kputint(rel_type);

        kputint(r_offset);

        switch (rel_type) {

        case R_386_GLOB_DAT:

        case R_386_JUMP_SLOT:

            kputint(16);

            sym_idx = ELF32_R_SYM(r_info);

            sym_addr = sym_table[sym_idx].st_value + bias;

            kputint(sym_idx);

            kputint(sym_addr);

            *(unsigned *)(r_offset+bias) = sym_addr;

            break;

        case R_386_32:

            kputint(16);

            sym_idx = ELF32_R_SYM(r_info);

            sym_addr = sym_table[sym_idx].st_value + bias;

            kputint(sym_idx);

            kputint(sym_addr);

            *(unsigned *)(r_offset+bias) += sym_addr;

            break;

        case R_386_RELATIVE:

            kputint(16);

            *(unsigned *)(r_offset+bias) += bias;

            break;

        }

    }

    kputint(-1);

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

        kputint(i);

        r_offset = jmp_rel_table[i].r_offset;

        r_info = jmp_rel_table[i].r_info;

        rel_type = ELF32_R_TYPE(r_info);

        kputint(rel_type);

        kputint(r_offset);

        switch (rel_type) {

        case R_386_GLOB_DAT:

        case R_386_JUMP_SLOT:

            kputint(16);

            sym_idx = ELF32_R_SYM(r_info);

            sym_addr = sym_table[sym_idx].st_value + bias;

            kputint(sym_idx);

            kputint(sym_addr);

            *(unsigned *)(r_offset+bias) = sym_addr;

            break;

        case R_386_32:

            kputint(16);

            sym_idx = ELF32_R_SYM(r_info);

            sym_addr = sym_table[sym_idx].st_value + bias;

            kputint(sym_idx);

            kputint(sym_addr);

            *(unsigned *)(r_offset+bias) += sym_addr;

            break;

        case R_386_RELATIVE:

            kputint(16);

            *(unsigned *)(r_offset+bias) += bias;

            break;

        }

    }

    kputint(-1);

    /* This will come in handy */

    runtime_env.rtld_dynamic = dynamic;

    runtime_env.rtld.bias = bias;

    /* Init libc and run rtld main */

    __main();

    kputint(33);

    __io_init();

    kputint(34);

    _rtld_main();

    kputint(35);

    __exit();

    kputint(36);

    asm (

        "movl $250, %%eax;"

        "int $0x30"

        : /* output */

        : /* input */

        : "%eax","%ecx","%edx" /* all scratch registers clobbered */

    );

}

/** @}

 */