grub/kern/i386/dl.c
okuji 4b13b216f4 2004-04-04 Yoshinori K. Okuji <okuji@enbug.org>
All symbols prefixed with PUPA_ and pupa_ are renamed to GRUB_
	and grub_, respectively. Because the conversion is trivial and
	mechanical, I omit the details here. Please refer to the CVS
	if you need more information.
2004-04-04 13:46:03 +00:00

126 lines
3.3 KiB
C

/* dl-386.c - arch-dependent part of loadable module support */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002 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 2 of the License, or
* (at your option) any later version.
*
* 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 GRUB; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <grub/dl.h>
#include <grub/elf.h>
#include <grub/misc.h>
#include <grub/err.h>
/* Check if EHDR is a valid ELF header. */
int
grub_arch_dl_check_header (void *ehdr, unsigned size)
{
Elf32_Ehdr *e = ehdr;
/* Check the header size. */
if (size < sizeof (Elf32_Ehdr))
return 0;
/* Check the magic numbers. */
if (e->e_ident[EI_MAG0] != ELFMAG0
|| e->e_ident[EI_MAG1] != ELFMAG1
|| e->e_ident[EI_MAG2] != ELFMAG2
|| e->e_ident[EI_MAG3] != ELFMAG3
|| e->e_version != EV_CURRENT
|| e->e_ident[EI_CLASS] != ELFCLASS32
|| e->e_ident[EI_DATA] != ELFDATA2LSB
|| e->e_machine != EM_386
|| e->e_type != ET_REL)
return 0;
/* Make sure that every section is within the core. */
if (size < e->e_shoff + e->e_shentsize * e->e_shnum)
return 0;
return 1;
}
/* Relocate symbols. */
grub_err_t
grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr)
{
Elf32_Ehdr *e = ehdr;
Elf32_Shdr *s;
Elf32_Sym *symtab;
Elf32_Word entsize;
unsigned i;
/* Find a symbol table. */
for (i = 0, s = (Elf32_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf32_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");
symtab = (Elf32_Sym *) ((char *) e + s->sh_offset);
entsize = s->sh_entsize;
for (i = 0, s = (Elf32_Shdr *) ((char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (Elf32_Shdr *) ((char *) s + e->e_shentsize))
if (s->sh_type == SHT_REL)
{
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)
{
Elf32_Rel *rel, *max;
for (rel = (Elf32_Rel *) ((char *) e + s->sh_offset),
max = rel + s->sh_size / s->sh_entsize;
rel < max;
rel++)
{
Elf32_Word *addr;
Elf32_Sym *sym;
if (seg->size < rel->r_offset)
return grub_error (GRUB_ERR_BAD_MODULE,
"reloc offset is out of the segment");
addr = (Elf32_Word *) ((char *) seg->addr + rel->r_offset);
sym = (Elf32_Sym *) ((char *) symtab
+ entsize * ELF32_R_SYM (rel->r_info));
switch (ELF32_R_TYPE (rel->r_info))
{
case R_386_32:
*addr += sym->st_value;
break;
case R_386_PC32:
*addr += (sym->st_value - (Elf32_Word) seg->addr
- rel->r_offset);
break;
}
}
}
}
return GRUB_ERR_NONE;
}