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/* vi: set sw=4 ts=4: */
/* Run an ELF binary on a linux system.
Copyright (C) 2002, Steven J. Hill (sjhill@realitydiluted.com)
This program 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, 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/* Program to load an ELF binary on a linux system, and run it.
References to symbols in sharable libraries can be resolved by either
an ELF sharable library or a linux style of shared library. */
/* Disclaimer: I have never seen any AT&T source code for SVr4, nor have
I ever taken any courses on internals. This program was developed using
information available through the book "UNIX SYSTEM V RELEASE 4,
Programmers guide: Ansi C and Programming Support Tools", which did
a more than adequate job of explaining everything required to get this
working. */
extern int _dl_linux_resolve(void);
#define OFFSET_GP_GOT 0x7ff0
unsigned long _dl_linux_resolver(unsigned long sym_index,
unsigned long old_gpreg)
{
unsigned long *got = (unsigned long *) (old_gpreg - OFFSET_GP_GOT);
struct elf_resolve *tpnt = (struct elf_resolve *) got[1];
Elf32_Sym *sym;
char *strtab;
unsigned long local_gotno;
unsigned long gotsym;
unsigned long value;
gotsym = tpnt->mips_gotsym;
local_gotno = tpnt->mips_local_gotno;
sym = ((Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr)) +
sym_index;
strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
value = (unsigned long) _dl_find_hash(strtab + sym->st_name,
tpnt->symbol_scope, tpnt, 1);
*(got + local_gotno + sym_index - gotsym) = value;
#ifdef DL_DEBUG
_dl_dprintf(2, "---RESOLVER---\n");
_dl_dprintf(2, "SYMTAB INDEX: %i\n", sym_index);
_dl_dprintf(2, " GOTSYM: %i\n", gotsym);
_dl_dprintf(2, " LOCAL GOTNO: %i\n", local_gotno);
_dl_dprintf(2, " VALUE: %x\n", value);
_dl_dprintf(2, " SYMBOL: %s\n\n", strtab + sym->st_name);
#endif
return value;
}
void _dl_parse_lazy_relocation_information(struct elf_resolve *tpnt,
unsigned long rel_addr, unsigned long rel_size, int type)
{
/* Nothing to do */
return;
}
int _dl_parse_copy_information(struct dyn_elf *xpnt, unsigned long rel_addr,
unsigned long rel_size, int type)
{
/* Nothing to do */
return 0;
}
int _dl_parse_relocation_information(struct elf_resolve *tpnt,
unsigned long rel_addr, unsigned long rel_size, int type)
{
Elf32_Sym *symtab;
Elf32_Rel *rpnt;
char *strtab;
unsigned long *got;
unsigned long *reloc_addr;
unsigned long symbol_addr;
int i, reloc_type, symtab_index;
/* Now parse the relocation information */
rel_size = rel_size / sizeof(Elf32_Rel);
rpnt = (Elf32_Rel *) (rel_addr + tpnt->loadaddr);
symtab = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);
strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
got = (unsigned long *) (tpnt->dynamic_info[DT_PLTGOT] + tpnt->loadaddr);
for (i = 0; i < rel_size; i++, rpnt++) {
reloc_addr = (unsigned long *) (tpnt->loadaddr +
(unsigned long) rpnt->r_offset);
reloc_type = ELF32_R_TYPE(rpnt->r_info);
symtab_index = ELF32_R_SYM(rpnt->r_info);
symbol_addr = 0;
if (!symtab_index && tpnt->libtype == program_interpreter)
continue;
switch (reloc_type) {
case R_MIPS_REL32:
if (symtab_index) {
if (symtab_index < tpnt->mips_gotsym)
*reloc_addr +=
symtab[symtab_index].st_value +
(unsigned long) tpnt->loadaddr;
else {
*reloc_addr += got[symtab_index + tpnt->mips_local_gotno -
tpnt->mips_gotsym];
}
}
else {
*reloc_addr += (unsigned long) tpnt->loadaddr;
}
break;
case R_MIPS_NONE:
break;
default:
_dl_dprintf(2, "%s: can't handle reloc type ", _dl_progname);
if (symtab_index)
_dl_dprintf(2, "'%s'\n", strtab + symtab[symtab_index].st_name);
_dl_exit(1);
};
};
return 0;
}
void _dl_perform_mips_global_got_relocations(struct elf_resolve *tpnt)
{
Elf32_Sym *sym;
char *strtab;
unsigned long i;
unsigned long *got_entry;
for (; tpnt ; tpnt = tpnt->next) {
/* We don't touch the dynamic linker */
if (tpnt->libtype == program_interpreter)
continue;
/* Setup the loop variables */
got_entry = (unsigned long *) (tpnt->loadaddr +
tpnt->dynamic_info[DT_PLTGOT]) + tpnt->mips_local_gotno;
sym = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] +
(unsigned long) tpnt->loadaddr) + tpnt->mips_gotsym;
strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] +
(unsigned long) tpnt->loadaddr);
i = tpnt->mips_symtabno - tpnt->mips_gotsym;
/* Relocate the global GOT entries for the object */
while(i--) {
#ifdef DL_DEBUG
_dl_dprintf(2,"BEFORE: %s=%x\n", strtab + sym->st_name,
*got_entry);
#endif
if (sym->st_shndx == SHN_UNDEF) {
if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC && sym->st_value)
*got_entry = sym->st_value + (unsigned long) tpnt->loadaddr;
else {
*got_entry = (unsigned long) _dl_find_hash(strtab +
sym->st_name, tpnt->symbol_scope, NULL, 1);
}
}
else if (sym->st_shndx == SHN_COMMON) {
*got_entry = (unsigned long) _dl_find_hash(strtab +
sym->st_name, tpnt->symbol_scope, NULL, 1);
}
else if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
*got_entry != sym->st_value)
*got_entry += (unsigned long) tpnt->loadaddr;
else if (ELF32_ST_TYPE(sym->st_info) == STT_SECTION) {
if (sym->st_other == 0)
*got_entry += (unsigned long) tpnt->loadaddr;
}
else {
*got_entry = (unsigned long) _dl_find_hash(strtab +
sym->st_name, tpnt->symbol_scope, NULL, 1);
}
#ifdef DL_DEBUG
if (*got_entry == 0)
_dl_dprintf(2,"ZERO: %s\n", strtab + sym->st_name);
else
_dl_dprintf(2," AFTER: %s=%x\n", strtab + sym->st_name,
*got_entry);
#endif
got_entry++;
sym++;
}
}
}
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