/* $OpenBSD: rtld_machine.c,v 1.14 2002/08/11 16:51:04 drahn Exp $ */ /* * Copyright (c) 1999 Dale Rahn * Copyright (c) 2001 Niklas Hallqvist * Copyright (c) 2001 Artur Grabowski * * 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. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed under OpenBSD by * Dale Rahn. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. * */ #define _DYN_LOADER #include #include #include #include #include #include #include "syscall.h" #include "archdep.h" #include "resolve.h" void _dl_bcopy(void *src, void *dest, int size) { unsigned char *psrc, *pdest; int i; psrc = src; pdest = dest; for (i = 0; i < size; i++) { pdest[i] = psrc[i]; } } int _dl_md_reloc(elf_object_t *object, int rel, int relasz) { long i; long numrela; long fails = 0; Elf64_Addr loff; Elf64_Rela *relas; struct load_list *llist; loff = object->load_offs; numrela = object->Dyn.info[relasz] / sizeof(Elf64_Rela); relas = (Elf64_Rela *)(object->Dyn.info[rel]); if (relas == NULL) return(0); /* * unprotect some segments if we need it. * XXX - we unprotect way to much. only the text can have cow * relocations. */ if ((rel == DT_REL || rel == DT_RELA)) { for (llist = object->load_list; llist != NULL; llist = llist->next) { if (!(llist->prot & PROT_WRITE)) { _dl_mprotect(llist->start, llist->size, llist->prot|PROT_WRITE); } } } for (i = 0; i < numrela; i++, relas++) { Elf64_Addr *r_addr; Elf64_Addr ooff; const Elf64_Sym *sym, *this; const char *symn; r_addr = (Elf64_Addr *)(relas->r_offset + loff); if (ELF64_R_SYM(relas->r_info) == 0xffffffff) continue; sym = object->dyn.symtab; sym += ELF64_R_SYM(relas->r_info); symn = object->dyn.strtab + sym->st_name; this = NULL; switch (ELF64_R_TYPE(relas->r_info)) { case R_TYPE(REFQUAD): ooff = _dl_find_symbol(symn, _dl_objects, &this, 0, 1, 0); if (this == NULL) goto resolve_failed; *r_addr += ooff + this->st_value + relas->r_addend; break; case R_TYPE(RELATIVE): /* * There is a lot of unaligned RELATIVE * relocs generated by gcc in the exception handlers. */ if ((((Elf_Addr) r_addr) & 0x7) != 0) { Elf_Addr tmp; #if 0 _dl_printf("unaligned RELATIVE: %p type: %d %s 0x%lx -> 0x%lx\n", r_addr, ELF_R_TYPE(relas->r_info), object->load_name, *r_addr, *r_addr+loff); #endif _dl_bcopy(r_addr, &tmp, sizeof(Elf_Addr)); tmp += loff; _dl_bcopy(&tmp, r_addr, sizeof(Elf_Addr)); } else *r_addr += loff; break; case R_TYPE(JMP_SLOT): ooff = _dl_find_symbol(symn, _dl_objects, &this, 0, 1, 1); if (this == NULL) goto resolve_failed; *r_addr = ooff + this->st_value + relas->r_addend; break; case R_TYPE(GLOB_DAT): ooff = _dl_find_symbol(symn, _dl_objects, &this, 0, 1, 0); if (this == NULL) goto resolve_failed; *r_addr = ooff + this->st_value + relas->r_addend; break; case R_TYPE(NONE): break; default: _dl_printf("%s:" " %s: unsupported relocation '%s' %d at %lx\n", _dl_progname, object->load_name, symn, ELF64_R_TYPE(relas->r_info), r_addr ); _dl_exit(1); } continue; resolve_failed: _dl_printf("%s: %s :can't resolve reference '%s'\n", _dl_progname, object->load_name, symn); fails++; } __asm __volatile("imb" : : : "memory"); /* reprotect the unprotected segments */ if ((rel == DT_REL || rel == DT_RELA)) { for (llist = object->load_list; llist != NULL; llist = llist->next) { if (!(llist->prot & PROT_WRITE)) _dl_mprotect(llist->start, llist->size, llist->prot); } } return (fails); } /* * Resolve a symbol at run-time. */ void * _dl_bind(elf_object_t *object, Elf_Word reloff) { Elf_RelA *rela; Elf_Addr *addr, ooff; const Elf_Sym *sym, *this; const char *symn; rela = (Elf_RelA *)(object->Dyn.info[DT_JMPREL] + reloff); sym = object->dyn.symtab; sym += ELF64_R_SYM(rela->r_info); symn = object->dyn.strtab + sym->st_name; addr = (Elf_Addr *)(object->load_offs + rela->r_offset); ooff = _dl_find_symbol(symn, _dl_objects, &this, 0, 1, 1); if (this == NULL) { _dl_printf("lazy binding failed!\n"); *((int *)0) = 0; /* XXX */ } *addr = ooff + this->st_value + rela->r_addend; return (void *)*addr; } /* * Relocate the Global Offset Table (GOT). */ void _dl_md_reloc_got(elf_object_t *object, int lazy) { Elf_Addr *pltgot; extern void _dl_bind_start(void); /* XXX */ pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT]; if (object->obj_type == OBJTYPE_LDR || !lazy || pltgot == NULL) { _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ); return; } if (object->obj_type != OBJTYPE_EXE) { int i, size; Elf_Addr *addr; Elf_RelA *rela; size = object->Dyn.info[DT_PLTRELSZ] / sizeof(Elf_RelA); rela = (Elf_RelA *)(object->Dyn.info[DT_JMPREL]); for (i = 0; i < size; i++) { addr = (Elf_Addr *)(object->load_offs + rela[i].r_offset); *addr += object->load_offs; } } pltgot[2] = (Elf_Addr)_dl_bind_start; pltgot[3] = (Elf_Addr)object; }