/* 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. */ #if defined (SUPPORT_LD_DEBUG) || defined (LD_DEBUG_SYMBOLS) static const char *_dl_reltypes_tab[] = { [0] "R_SH_NONE", "R_SH_DIR32", "R_SH_REL32", "R_SH_DIR8WPN", [4] "R_SH_IND12W", "R_SH_DIR8WPL", "R_SH_DIR8WPZ", "R_SH_DIR8BP", [8] "R_SH_DIR8W", "R_SH_DIR8L", [25] "R_SH_SWITCH16","R_SH_SWITCH32","R_SH_USES", [28] "R_SH_COUNT", "R_SH_ALIGN", "R_SH_CODE", "R_SH_DATA", [32] "R_SH_LABEL", "R_SH_SWITCH8", "R_SH_GNU_VTINHERIT","R_SH_GNU_VTENTRY", [160] "R_SH_GOT32", "R_SH_PLT32", "R_SH_COPY", "R_SH_GLOB_DAT", [164] "R_SH_JMP_SLOT","R_SH_RELATIVE","R_SH_GOTOFF", "R_SH_GOTPC", }; static const char * _dl_reltypes(int type) { static char buf[22]; const char *str; if (type >= (sizeof (_dl_reltypes_tab)/sizeof(_dl_reltypes_tab[0])) || NULL == (str = _dl_reltypes_tab[type])) { str =_dl_simple_ltoa( buf, (unsigned long)(type)); } return str; } static void debug_sym(Elf32_Sym *symtab,char *strtab,int symtab_index) { if(_dl_debug_symbols) { if(symtab_index){ _dl_dprintf(_dl_debug_file, "\n%s\tvalue=%x\tsize=%x\tinfo=%x\tother=%x\tshndx=%x", strtab + symtab[symtab_index].st_name, symtab[symtab_index].st_value, symtab[symtab_index].st_size, symtab[symtab_index].st_info, symtab[symtab_index].st_other, symtab[symtab_index].st_shndx); } } } static void debug_reloc(Elf32_Sym *symtab,char *strtab, ELF_RELOC *rpnt) { if(_dl_debug_reloc) { int symtab_index; const char *sym; symtab_index = ELF32_R_SYM(rpnt->r_info); sym = symtab_index ? strtab + symtab[symtab_index].st_name : "sym=0x0"; #ifdef ELF_USES_RELOCA _dl_dprintf(_dl_debug_file, "\n%s\toffset=%x\taddend=%x %s", _dl_reltypes(ELF32_R_TYPE(rpnt->r_info)), rpnt->r_offset, rpnt->r_addend, sym); #else _dl_dprintf(_dl_debug_file, "\n%s\toffset=%x %s", _dl_reltypes(ELF32_R_TYPE(rpnt->r_info)), rpnt->r_offset, sym); #endif } } #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 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; rel_addr = (char *) (tpnt->dynamic_info[DT_JMPREL] + tpnt->loadaddr); this_reloc = (ELF_RELOC *) (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); if (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 + (unsigned long) tpnt->loadaddr); got_addr = (char **) instr_addr; /* Get the address of the GOT entry */ new_addr = _dl_find_hash(strtab + symtab[symtab_index].st_name, tpnt->symbol_scope, tpnt, resolver); if (!new_addr) { _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) || defined (LD_NEVER_FIXUP_SYMBOLS) if ((unsigned long) got_addr < 0x20000000) { #ifndef SUPPORT_LD_DEBUG if (_dl_debug_bindings) { _dl_dprintf(_dl_debug_file, "\nresolve function: %s", strtab + symtab[symtab_index].st_name); if(_dl_debug_detail) _dl_dprintf(_dl_debug_file, "\tpatch %x ==> %x @ %x", *got_addr, new_addr, got_addr); } #endif #ifndef LD_NEVER_FIXUP_SYMBOLS *got_addr = new_addr; #endif } else { *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)) { int i; char *strtab; int goof = 0; Elf32_Sym *symtab; ELF_RELOC *rpnt; int symtab_index; /* Now parse the relocation information */ rpnt = (ELF_RELOC *) (rel_addr + tpnt->loadaddr); rel_size = rel_size / sizeof(ELF_RELOC); 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++, rpnt++) { int res; 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; #if defined (SUPPORT_LD_DEBUG) debug_sym(symtab,strtab,symtab_index); debug_reloc(symtab,strtab,rpnt); #endif 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 (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); } else if (res >0) { _dl_dprintf(2, "can't resolve symbol '%s'\n"); goof += res; } } return goof; } 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; unsigned long *reloc_addr; unsigned long symbol_addr; int goof = 0; 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) { symbol_addr = (unsigned long) _dl_find_hash(strtab + symtab[symtab_index].st_name, scope, (reloc_type == R_SH_JMP_SLOT ? tpnt : NULL), symbolrel); /* * 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_GLOBAL) { goof++; } } #if defined (SUPPORT_LD_DEBUG) { unsigned long old_val = *reloc_addr; #endif switch (reloc_type) { case R_SH_NONE: break; case R_SH_COPY: /* handled later on */ break; case R_SH_DIR32: *reloc_addr += symbol_addr + rpnt->r_addend; break; case R_SH_JMP_SLOT: *reloc_addr = symbol_addr + rpnt->r_addend; break; case R_SH_REL32: *reloc_addr += rpnt->r_addend - (unsigned long) tpnt->loadaddr; break; case R_SH_RELATIVE: *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, "\tpatch: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr); } #endif return goof; } 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; reloc_addr = (unsigned long *) (tpnt->loadaddr + (unsigned long) rpnt->r_offset); reloc_type = ELF32_R_TYPE(rpnt->r_info); #if defined (SUPPORT_LD_DEBUG) { unsigned long 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, "\tpatch: %x ==> %x @ %x", old_val, *reloc_addr, reloc_addr); } #endif return 0; } /* 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 */ static int _dl_do_copy (struct elf_resolve *tpnt, struct dyn_elf *scope, ELF_RELOC *rpnt, Elf32_Sym *symtab, char *strtab) { int reloc_type; int symtab_index; unsigned long *reloc_addr; unsigned long symbol_addr; int goof = 0; reloc_addr = (unsigned long *) (tpnt->loadaddr + (unsigned long) rpnt->r_offset); reloc_type = ELF32_R_TYPE(rpnt->r_info); if (reloc_type != R_SH_COPY) return 0; symtab_index = ELF32_R_SYM(rpnt->r_info); symbol_addr = 0; if (symtab_index) { symbol_addr = (unsigned long) _dl_find_hash(strtab + symtab[symtab_index].st_name, scope, NULL, copyrel); if (!symbol_addr) goof++; } if (!goof) { #if defined (SUPPORT_LD_DEBUG) if(_dl_debug_move) _dl_dprintf(_dl_debug_file,"\n%s move %x bytes from %x to %x", strtab + symtab[symtab_index].st_name, symtab[symtab_index].st_size, symbol_addr, symtab[symtab_index].st_value); #endif _dl_memcpy((char *) symtab[symtab_index].st_value, (char *) symbol_addr, symtab[symtab_index].st_size); } return goof; } void _dl_parse_lazy_relocation_information(struct elf_resolve *tpnt, unsigned long rel_addr, unsigned long rel_size, int type) { (void)_dl_parse(tpnt, NULL, rel_addr, rel_size, _dl_do_lazy_reloc); } int _dl_parse_relocation_information(struct elf_resolve *tpnt, unsigned long rel_addr, unsigned long rel_size, int type) { return _dl_parse(tpnt, tpnt->symbol_scope, rel_addr, rel_size, _dl_do_reloc); } int _dl_parse_copy_information(struct dyn_elf *xpnt, unsigned long rel_addr, unsigned long rel_size, int type) { return _dl_parse(xpnt->dyn, xpnt->next, rel_addr, rel_size, _dl_do_copy); }