114 lines
3 KiB
C
114 lines
3 KiB
C
/* dl-386.c - arch-dependent part of loadable module support */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2002,2005,2007,2009 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/dl.h>
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#include <grub/elf.h>
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#include <grub/misc.h>
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#include <grub/err.h>
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#include <grub/i18n.h>
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/* Check if EHDR is a valid ELF header. */
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grub_err_t
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grub_arch_dl_check_header (void *ehdr)
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{
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Elf_Ehdr *e = ehdr;
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/* Check the magic numbers. */
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if (e->e_ident[EI_CLASS] != ELFCLASS32
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|| e->e_ident[EI_DATA] != ELFDATA2LSB
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|| e->e_machine != EM_386)
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return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch dependent ELF magic"));
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return GRUB_ERR_NONE;
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}
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/* Relocate symbols. */
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grub_err_t
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grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr)
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{
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Elf_Ehdr *e = ehdr;
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Elf_Shdr *s;
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Elf_Word entsize;
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unsigned i;
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/* Find a symbol table. */
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for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
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i < e->e_shnum;
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i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
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if (s->sh_type == SHT_SYMTAB)
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break;
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if (i == e->e_shnum)
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return grub_error (GRUB_ERR_BAD_MODULE, N_("no symbol table"));
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entsize = s->sh_entsize;
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for (i = 0, s = (Elf_Shdr *) ((char *) e + e->e_shoff);
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i < e->e_shnum;
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i++, s = (Elf_Shdr *) ((char *) s + e->e_shentsize))
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if (s->sh_type == SHT_REL)
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{
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grub_dl_segment_t seg;
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/* Find the target segment. */
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for (seg = mod->segment; seg; seg = seg->next)
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if (seg->section == s->sh_info)
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break;
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if (seg)
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{
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Elf_Rel *rel, *max;
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for (rel = (Elf_Rel *) ((char *) e + s->sh_offset),
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max = rel + s->sh_size / s->sh_entsize;
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rel < max;
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rel++)
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{
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Elf_Word *addr;
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Elf_Sym *sym;
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if (seg->size < rel->r_offset)
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return grub_error (GRUB_ERR_BAD_MODULE,
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"reloc offset is out of the segment");
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addr = (Elf_Word *) ((char *) seg->addr + rel->r_offset);
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sym = (Elf_Sym *) ((char *) mod->symtab
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+ entsize * ELF_R_SYM (rel->r_info));
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switch (ELF_R_TYPE (rel->r_info))
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{
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case R_386_32:
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*addr += sym->st_value;
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break;
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case R_386_PC32:
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*addr += (sym->st_value - (Elf_Word) seg->addr
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- rel->r_offset);
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break;
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default:
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return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
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N_("relocation 0x%x is not implemented yet"),
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ELF_R_TYPE (rel->r_info));
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}
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}
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}
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}
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return GRUB_ERR_NONE;
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}
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