127 lines
3.4 KiB
C
127 lines
3.4 KiB
C
/* dl-386.c - arch-dependent part of loadable module support */
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/*
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* PUPA -- Preliminary Universal Programming Architecture for GRUB
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* Copyright (C) 2002 Yoshinori K. Okuji <okuji@enbug.org>
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*
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* PUPA 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 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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 PUPA; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <pupa/dl.h>
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#include <pupa/elf.h>
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#include <pupa/misc.h>
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#include <pupa/err.h>
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/* Check if EHDR is a valid ELF header. */
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int
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pupa_arch_dl_check_header (void *ehdr, unsigned size)
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{
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Elf32_Ehdr *e = ehdr;
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/* Check the header size. */
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if (size < sizeof (Elf32_Ehdr))
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return 0;
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/* Check the magic numbers. */
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if (e->e_ident[EI_MAG0] != ELFMAG0
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|| e->e_ident[EI_MAG1] != ELFMAG1
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|| e->e_ident[EI_MAG2] != ELFMAG2
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|| e->e_ident[EI_MAG3] != ELFMAG3
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|| e->e_version != EV_CURRENT
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|| 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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|| e->e_type != ET_REL)
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return 0;
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/* Make sure that every section is within the core. */
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if (size < e->e_shoff + e->e_shentsize * e->e_shnum)
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return 0;
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return 1;
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}
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/* Relocate symbols. */
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pupa_err_t
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pupa_arch_dl_relocate_symbols (pupa_dl_t mod, void *ehdr)
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{
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Elf32_Ehdr *e = ehdr;
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Elf32_Shdr *s;
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Elf32_Sym *symtab;
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Elf32_Word entsize;
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unsigned i;
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/* Find a symbol table. */
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for (i = 0, s = (Elf32_Shdr *) ((char *) e + e->e_shoff);
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i < e->e_shnum;
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i++, s = (Elf32_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 pupa_error (PUPA_ERR_BAD_MODULE, "no symtab found");
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symtab = (Elf32_Sym *) ((char *) e + s->sh_offset);
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entsize = s->sh_entsize;
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for (i = 0, s = (Elf32_Shdr *) ((char *) e + e->e_shoff);
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i < e->e_shnum;
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i++, s = (Elf32_Shdr *) ((char *) s + e->e_shentsize))
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if (s->sh_type == SHT_REL)
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{
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pupa_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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Elf32_Rel *rel, *max;
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for (rel = (Elf32_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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Elf32_Word *addr;
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Elf32_Sym *sym;
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if (seg->size < rel->r_offset)
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return pupa_error (PUPA_ERR_BAD_MODULE,
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"reloc offset is out of the segment");
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addr = (Elf32_Word *) ((char *) seg->addr + rel->r_offset);
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sym = (Elf32_Sym *) ((char *) symtab
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+ entsize * ELF32_R_SYM (rel->r_info));
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switch (ELF32_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 - (Elf32_Word) seg->addr
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- rel->r_offset);
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break;
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}
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}
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}
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}
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return PUPA_ERR_NONE;
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}
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