/* vi: set sw=4 ts=4: */ /* SuperH ELF shared library loader suppport * * Copyright (C) 2002, Stefan Allius and * Eddie C. Dost * * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. The name of the above contributors may not be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* 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. */ #include "ldso.h" extern int _dl_linux_resolve(void); unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry) { int reloc_type; ELF_RELOC *this_reloc; char *strtab; Elf32_Sym *symtab; int symtab_index; char *rel_addr; char *new_addr; char **got_addr; unsigned long instr_addr; char *symname; rel_addr = (char *)tpnt->dynamic_info[DT_JMPREL]; this_reloc = (ELF_RELOC *)(intptr_t)(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 *)(intptr_t) tpnt->dynamic_info[DT_SYMTAB]; strtab = (char *)tpnt->dynamic_info[DT_STRTAB]; symname = strtab + symtab[symtab_index].st_name; if (unlikely(reloc_type != R_SH_JMP_SLOT)) { _dl_dprintf(2, "%s: Incorrect relocation type in jump relocations\n", _dl_progname); _dl_exit(1); } /* Address of jump instruction to fix up */ instr_addr = (unsigned long) (this_reloc->r_offset + tpnt->loadaddr); got_addr = (char **) instr_addr; /* Get the address of the GOT entry */ new_addr = _dl_find_hash(symname, tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT); if (unlikely(!new_addr)) { _dl_dprintf(2, "%s: can't resolve symbol '%s'\n", _dl_progname, symname); _dl_exit(1); } #if defined (__SUPPORT_LD_DEBUG__) if ((unsigned long) got_addr < 0x20000000) { if (_dl_debug_bindings) { _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname); if(_dl_debug_detail) _dl_dprintf(_dl_debug_file, "\n\tpatched %x ==> %x @ %x\n", *got_addr, new_addr, got_addr); } } if (!_dl_debug_nofixups) *got_addr = new_addr; #else *got_addr = new_addr; #endif return (unsigned long) new_addr; } static int _dl_parse(struct elf_resolve *tpnt, struct dyn_elf *scope, unsigned long rel_addr, unsigned long rel_size, int (*reloc_fnc) (struct elf_resolve *tpnt, struct dyn_elf *scope, ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab)) { unsigned int i; char *strtab; Elf32_Sym *symtab; ELF_RELOC *rpnt; int symtab_index; /* Now parse the relocation information */ rpnt = (ELF_RELOC *)(intptr_t) rel_addr; rel_size = rel_size / sizeof(ELF_RELOC); symtab = (Elf32_Sym *)(intptr_t)tpnt->dynamic_info[DT_SYMTAB]; strtab = (char *)tpnt->dynamic_info[DT_STRTAB]; for (i = 0; i < rel_size; i++, rpnt++) { int res; symtab_index = ELF32_R_SYM(rpnt->r_info); debug_sym(symtab,strtab,symtab_index); debug_reloc(symtab,strtab,rpnt); res = reloc_fnc(tpnt, scope, rpnt, symtab, strtab); if (res == 0) continue; _dl_dprintf(2, "\n%s: ",_dl_progname); if (symtab_index) _dl_dprintf(2, "symbol '%s': ", strtab + symtab[symtab_index].st_name); if (unlikely(res < 0)) { int reloc_type = ELF32_R_TYPE(rpnt->r_info); #if defined (__SUPPORT_LD_DEBUG__) _dl_dprintf(2, "can't handle reloc type %s\n ", _dl_reltypes(reloc_type)); #else _dl_dprintf(2, "can't handle reloc type %x\n", reloc_type); #endif _dl_exit(-res); } if (unlikely(res > 0)) { _dl_dprintf(2, "can't resolve symbol\n"); return res; } } return 0; } static int _dl_do_reloc (struct elf_resolve *tpnt,struct dyn_elf *scope, ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab) { int reloc_type; int symtab_index; char *symname; unsigned long *reloc_addr; unsigned long symbol_addr; #if defined (__SUPPORT_LD_DEBUG__) unsigned long old_val; #endif reloc_addr = (unsigned long *)(intptr_t) (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; symname = strtab + symtab[symtab_index].st_name; if (symtab_index) { symbol_addr = (unsigned long) _dl_find_hash(symname, scope, tpnt, elf_machine_type_class(reloc_type)); /* * We want to allow undefined references to weak symbols - this might * have been intentional. We should not be linking local symbols * here, so all bases should be covered. */ if (!symbol_addr && ELF32_ST_BIND(symtab[symtab_index].st_info) != STB_WEAK) { _dl_dprintf(2, "%s: can't resolve symbol '%s'\n", _dl_progname, strtab + symtab[symtab_index].st_name); _dl_exit (1); } } #if defined (__SUPPORT_LD_DEBUG__) old_val = *reloc_addr; #endif switch (reloc_type) { case R_SH_NONE: break; case R_SH_COPY: if (symbol_addr) { #if defined (__SUPPORT_LD_DEBUG__) if(_dl_debug_move) _dl_dprintf(_dl_debug_file,"\n%s move %x bytes from %x to %x", symname, symtab[symtab_index].st_size, symbol_addr, reloc_addr); #endif _dl_memcpy((char *) reloc_addr, (char *) symbol_addr, symtab[symtab_index].st_size); } return 0; /* no further LD_DEBUG messages for copy relocs */ case R_SH_DIR32: case R_SH_GLOB_DAT: case R_SH_JMP_SLOT: *reloc_addr = symbol_addr + rpnt->r_addend; break; case R_SH_REL32: *reloc_addr = symbol_addr + rpnt->r_addend - (unsigned long) reloc_addr; break; case R_SH_RELATIVE: *reloc_addr = (unsigned long) tpnt->loadaddr + rpnt->r_addend; break; default: return -1; /*call _dl_exit(1) */ } #if defined (__SUPPORT_LD_DEBUG__) if(_dl_debug_reloc && _dl_debug_detail) _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr); #endif return 0; } static int _dl_do_lazy_reloc (struct elf_resolve *tpnt, struct dyn_elf *scope, ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab) { int reloc_type; unsigned long *reloc_addr; #if defined (__SUPPORT_LD_DEBUG__) unsigned long old_val; #endif (void)scope; (void)symtab; (void)strtab; reloc_addr = (unsigned long *)(intptr_t) (tpnt->loadaddr + (unsigned long) rpnt->r_offset); reloc_type = ELF32_R_TYPE(rpnt->r_info); #if defined (__SUPPORT_LD_DEBUG__) old_val = *reloc_addr; #endif switch (reloc_type) { case R_SH_NONE: break; case R_SH_JMP_SLOT: *reloc_addr += (unsigned long) tpnt->loadaddr; break; default: return -1; /*call _dl_exit(1) */ } #if defined (__SUPPORT_LD_DEBUG__) if(_dl_debug_reloc && _dl_debug_detail) _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr); #endif return 0; } void _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt, unsigned long rel_addr, unsigned long rel_size) { (void)_dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, _dl_do_lazy_reloc); } int _dl_parse_relocation_information(struct dyn_elf *rpnt, unsigned long rel_addr, unsigned long rel_size) { return _dl_parse(rpnt->dyn, rpnt->dyn->symbol_scope, rel_addr, rel_size, _dl_do_reloc); }