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/* Run an ELF binary on a linux system.
Copyright (C) 1995, Eric Youngdale.
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. */
#ifndef VERBOSE_DLINKER
#define VERBOSE_DLINKER
#endif
#ifdef VERBOSE_DLINKER
static const char * _dl_reltypes[] = { "R_SPARC_NONE", "R_SPARC_8",
"R_SPARC_16", "R_SPARC_32", "R_SPARC_DISP8", "R_SPARC_DISP16",
"R_SPARC_DISP32", "R_SPARC_WDISP30", "R_SPARC_WDISP22",
"R_SPARC_HI22", "R_SPARC_22", "R_SPARC_13", "R_SPARC_LO10",
"R_SPARC_GOT10", "R_SPARC_GOT13", "R_SPARC_GOT22", "R_SPARC_PC10",
"R_SPARC_PC22", "R_SPARC_WPLT30", "R_SPARC_COPY",
"R_SPARC_GLOB_DAT", "R_SPARC_JMP_SLOT", "R_SPARC_RELATIVE",
"R_SPARC_UA32"};
#endif
/* 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 _dl_linux_resolve(void);
unsigned int _dl_linux_resolver(unsigned int reloc_entry, unsigned int * plt)
{
int reloc_type;
Elf32_Rela * this_reloc;
char * strtab;
Elf32_Sym * symtab;
Elf32_Rela * rel_addr;
struct elf_resolve * tpnt;
int symtab_index;
char * new_addr;
char ** got_addr;
unsigned int instr_addr;
tpnt = (struct elf_resolve *) plt[2];
rel_addr = (Elf32_Rela *) (tpnt->dynamic_info[DT_JMPREL] +
tpnt->loadaddr);
/*
* Generate the correct relocation index into the .rela.plt section.
*/
reloc_entry = (reloc_entry >> 12) - 0xc;
this_reloc = (Elf32_Rela *) ((char *) rel_addr + reloc_entry);
reloc_type = ELF32_R_TYPE(this_reloc->r_info);
symtab_index = ELF32_R_SYM(this_reloc->r_info);
symtab = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);
strtab = (char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
_dl_dprintf(2, "tpnt = %x\n", tpnt);
_dl_dprintf(2, "reloc = %x\n", this_reloc);
_dl_dprintf(2, "symtab = %x\n", symtab);
_dl_dprintf(2, "strtab = %x\n", strtab);
if (reloc_type != R_SPARC_JMP_SLOT) {
_dl_dprintf(2, "%s: incorrect relocation type in jump relocations (%d)\n",
_dl_progname, reloc_type);
_dl_exit(30);
};
/* Address of jump instruction to fix up */
instr_addr = ((int)this_reloc->r_offset + (int)tpnt->loadaddr);
got_addr = (char **) instr_addr;
_dl_dprintf(2, "symtab_index %d\n", symtab_index);
#ifdef DL_DEBUG_SYMBOLS
_dl_dprintf(2, "Resolving symbol %s\n",
strtab + symtab[symtab_index].st_name);
#endif
/* Get the address of the GOT entry */
new_addr = _dl_find_hash(strtab + symtab[symtab_index].st_name,
tpnt->symbol_scope, tpnt, 0);
if(!new_addr) {
_dl_dprintf(2, "%s: can't resolve symbol '%s'\n",
_dl_progname, strtab + symtab[symtab_index].st_name);
_dl_exit(31);
};
#ifdef DL_NEVER_FIXUP_SYMBOLS
if((unsigned int) got_addr < 0x40000000) {
_dl_dprintf(2, "Calling library function: %s\n",
strtab + symtab[symtab_index].st_name);
} else {
got_addr[1] = (char *) (0x03000000 | (((unsigned int) new_addr >> 10) & 0x3fffff));
got_addr[2] = (char *) (0x81c06000 | ((unsigned int) new_addr & 0x3ff));
}
#else
got_addr[1] = (char *) (0x03000000 | (((unsigned int) new_addr >> 10) & 0x3fffff));
got_addr[2] = (char *) (0x81c06000 | ((unsigned int) new_addr & 0x3ff));
#endif
_dl_dprintf(2, "Address = %x\n",new_addr);
_dl_exit(32);
return (unsigned int) new_addr;
}
void _dl_parse_lazy_relocation_information(struct elf_resolve * tpnt, int rel_addr,
int rel_size, int type){
int i;
char * strtab;
int reloc_type;
int symtab_index;
Elf32_Sym * symtab;
Elf32_Rela * rpnt;
unsigned int * reloc_addr;
/* Now parse the relocation information */
rpnt = (Elf32_Rela *) (rel_addr + tpnt->loadaddr);
symtab = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);
strtab = ( char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
for(i=0; i< rel_size; i += sizeof(Elf32_Rela), rpnt++){
reloc_addr = (int *) (tpnt->loadaddr + (int)rpnt->r_offset);
reloc_type = ELF32_R_TYPE(rpnt->r_info);
symtab_index = ELF32_R_SYM(rpnt->r_info);
/* When the dynamic linker bootstrapped itself, it resolved some symbols.
Make sure we do not do them again */
if(!symtab_index && tpnt->libtype == program_interpreter) continue;
if(symtab_index && tpnt->libtype == program_interpreter &&
_dl_symbol(strtab + symtab[symtab_index].st_name))
continue;
switch(reloc_type){
case R_SPARC_NONE:
break;
case R_SPARC_JMP_SLOT:
break;
default:
_dl_dprintf(2, "%s: (LAZY) can't handle reloc type ", _dl_progname);
#ifdef VERBOSE_DLINKER
_dl_dprintf(2, "%s ", _dl_reltypes[reloc_type]);
#endif
if(symtab_index) _dl_dprintf(2, "'%s'\n",
strtab + symtab[symtab_index].st_name);
_dl_exit(33);
};
};
}
int _dl_parse_relocation_information(struct elf_resolve * tpnt, int rel_addr,
int rel_size, int type){
int i;
char * strtab;
int reloc_type;
int goof = 0;
Elf32_Sym * symtab;
Elf32_Rela * rpnt;
unsigned int * reloc_addr;
unsigned int symbol_addr;
int symtab_index;
/* Now parse the relocation information */
rpnt = (Elf32_Rela *) (rel_addr + tpnt->loadaddr);
symtab = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);
strtab = ( char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
for(i=0; i< rel_size; i+= sizeof(Elf32_Rela), rpnt++){
reloc_addr = (int *) (tpnt->loadaddr + (int)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;
if(symtab_index) {
if(tpnt->libtype == program_interpreter &&
_dl_symbol(strtab + symtab[symtab_index].st_name))
continue;
symbol_addr = (unsigned int)
_dl_find_hash(strtab + symtab[symtab_index].st_name,
tpnt->symbol_scope,
(reloc_type == R_SPARC_JMP_SLOT ? tpnt : NULL), 0);
if(!symbol_addr &&
ELF32_ST_BIND(symtab [symtab_index].st_info) == STB_GLOBAL) {
_dl_dprintf(2, "%s: can't resolve symbol '%s'\n",
_dl_progname, strtab + symtab[symtab_index].st_name);
goof++;
};
};
switch(reloc_type){
case R_SPARC_NONE:
break;
case R_SPARC_32:
*reloc_addr = symbol_addr + rpnt->r_addend;
break;
case R_SPARC_DISP32:
*reloc_addr = symbol_addr + rpnt->r_addend - (unsigned int) reloc_addr;
break;
case R_SPARC_GLOB_DAT:
*reloc_addr = symbol_addr + rpnt->r_addend;
break;
case R_SPARC_JMP_SLOT:
reloc_addr[1] = 0x03000000 | ((symbol_addr >> 10) & 0x3fffff);
reloc_addr[2] = 0x81c06000 | (symbol_addr & 0x3ff);
break;
case R_SPARC_RELATIVE:
*reloc_addr += (unsigned int) tpnt->loadaddr + rpnt->r_addend;
break;
case R_SPARC_HI22:
if (!symbol_addr)
symbol_addr = tpnt->loadaddr + rpnt->r_addend;
else
symbol_addr += rpnt->r_addend;
*reloc_addr = (*reloc_addr & 0xffc00000)|(symbol_addr >> 10);
break;
case R_SPARC_LO10:
if (!symbol_addr)
symbol_addr = tpnt->loadaddr + rpnt->r_addend;
else
symbol_addr += rpnt->r_addend;
*reloc_addr = (*reloc_addr & ~0x3ff)|(symbol_addr & 0x3ff);
break;
case R_SPARC_WDISP30:
*reloc_addr = (*reloc_addr & 0xc0000000)|
((symbol_addr - (unsigned int) reloc_addr) >> 2);
break;
case R_SPARC_COPY:
#if 0 /* This one is done later */
_dl_dprintf(2, "Doing copy for symbol ");
if(symtab_index) _dl_dprintf(2, strtab + symtab[symtab_index].st_name);
_dl_dprintf(2, "\n");
_dl_memcpy((void *) symtab[symtab_index].st_value,
(void *) symbol_addr,
symtab[symtab_index].st_size);
#endif
break;
default:
_dl_dprintf(2, "%s: can't handle reloc type ", _dl_progname);
#ifdef VERBOSE_DLINKER
_dl_dprintf(2, "%s ", _dl_reltypes[reloc_type]);
#endif
if (symtab_index)
_dl_dprintf(2, "'%s'\n", strtab + symtab[symtab_index].st_name);
_dl_exit(34);
};
};
return goof;
}
/* This is done as a separate step, because there are cases where
information is first copied and later initialized. This results in
the wrong information being copied. Someone at Sun was complaining about
a bug in the handling of _COPY by SVr4, and this may in fact be what he
was talking about. Sigh. */
/* No, there are cases where the SVr4 linker fails to emit COPY relocs
at all */
int _dl_parse_copy_information(struct dyn_elf * xpnt, int rel_addr,
int rel_size, int type)
{
int i;
char * strtab;
int reloc_type;
int goof = 0;
Elf32_Sym * symtab;
Elf32_Rela * rpnt;
unsigned int * reloc_addr;
unsigned int symbol_addr;
struct elf_resolve *tpnt;
int symtab_index;
/* Now parse the relocation information */
tpnt = xpnt->dyn;
rpnt = (Elf32_Rela *) (rel_addr + tpnt->loadaddr);
symtab = (Elf32_Sym *) (tpnt->dynamic_info[DT_SYMTAB] + tpnt->loadaddr);
strtab = ( char *) (tpnt->dynamic_info[DT_STRTAB] + tpnt->loadaddr);
for(i=0; i< rel_size; i+= sizeof(Elf32_Rela), rpnt++){
reloc_addr = (int *) (tpnt->loadaddr + (int)rpnt->r_offset);
reloc_type = ELF32_R_TYPE(rpnt->r_info);
if(reloc_type != R_SPARC_COPY) continue;
symtab_index = ELF32_R_SYM(rpnt->r_info);
symbol_addr = 0;
if(!symtab_index && tpnt->libtype == program_interpreter) continue;
if(symtab_index) {
if(tpnt->libtype == program_interpreter &&
_dl_symbol(strtab + symtab[symtab_index].st_name))
continue;
symbol_addr = (unsigned int)
_dl_find_hash(strtab + symtab[symtab_index].st_name,
xpnt->next, NULL, 1);
if(!symbol_addr) {
_dl_dprintf(2, "%s: can't resolve symbol '%s'\n",
_dl_progname, strtab + symtab[symtab_index].st_name);
goof++;
};
};
if (!goof)
_dl_memcpy((char *) symtab[symtab_index].st_value,
(char *) symbol_addr,
symtab[symtab_index].st_size);
};
return goof;
}
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