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/* dl-x86_64.c - arch-dependent part of loadable module support */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002,2005,2007,2009 Free Software Foundation, Inc.
*
* GRUB 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.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/dl.h>
#include <grub/elf.h>
#include <grub/misc.h>
#include <grub/err.h>
/* Check if EHDR is a valid ELF header. */
grub_err_t
grub_arch_dl_check_header (void *ehdr)
{
Elf64_Ehdr *e = ehdr;
/* Check the magic numbers. */
if (e->e_ident[EI_CLASS] != ELFCLASS64
|| e->e_ident[EI_DATA] != ELFDATA2LSB
|| e->e_machine != EM_X86_64)
return grub_error (GRUB_ERR_BAD_OS, "invalid arch specific ELF magic");
return GRUB_ERR_NONE;
}
/* Relocate symbols. */
grub_err_t
grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr)
{
Elf64_Ehdr *e = ehdr;
Elf64_Shdr *s;
Elf64_Word entsize;
unsigned i;
/* Find a symbol table. */
for (i = 0, s = (Elf64_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf64_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_SYMTAB)
break;
if (i == e->e_shnum)
return grub_error (GRUB_ERR_BAD_MODULE, "no symtab found");
entsize = s->sh_entsize;
for (i = 0, s = (Elf64_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf64_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_RELA)
{
grub_dl_segment_t seg;
/* Find the target segment. */
for (seg = mod->segment; seg; seg = seg->next)
if (seg->section == s->sh_info)
break;
if (seg)
{
Elf64_Rela *rel, *max;
for (rel = (Elf64_Rela *) ((char *) e + s->sh_offset),
max = rel + s->sh_size / s->sh_entsize;
rel < max;
rel++)
{
Elf64_Word *addr32;
Elf64_Xword *addr64;
Elf64_Sym *sym;
if (seg->size < rel->r_offset)
return grub_error (GRUB_ERR_BAD_MODULE,
"reloc offset is out of the segment");
addr32 = (Elf64_Word *) ((char *) seg->addr + rel->r_offset);
addr64 = (Elf64_Xword *) addr32;
sym = (Elf64_Sym *) ((char *) mod->symtab
+ entsize * ELF_R_SYM (rel->r_info));
switch (ELF_R_TYPE (rel->r_info))
{
case R_X86_64_64:
*addr64 += rel->r_addend + sym->st_value;
break;
case R_X86_64_PC32:
*addr32 += rel->r_addend + sym->st_value -
(Elf64_Xword) seg->addr - rel->r_offset;
break;
case R_X86_64_32:
case R_X86_64_32S:
*addr32 += rel->r_addend + sym->st_value;
break;
default:
grub_fatal ("Unrecognized relocation: %d\n", ELF_R_TYPE (rel->r_info));
}
}
}
}
return GRUB_ERR_NONE;
}
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