/* Relocate a shared object and resolve its references to other loaded objects. Copyright (C) 1995,96,97,98,99,2000,2001 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include #include #include #include #include #include #include #include #include "dynamic-link.h" /* Statistics function. */ unsigned long int _dl_num_cache_relocations; void _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], int lazy, int consider_profiling) { if (l->l_relocated) return; /* If DT_BIND_NOW is set relocate all references in this object. We do not do this if we are profiling, of course. */ if (!consider_profiling && __builtin_expect (l->l_info[DT_BIND_NOW] != NULL, 0)) lazy = 0; if (__builtin_expect (_dl_debug_mask & DL_DEBUG_RELOC, 0)) _dl_printf ("\nrelocation processing: %s%s\n", l->l_name[0] ? l->l_name : _dl_argv[0], lazy ? " (lazy)" : ""); if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0)) { /* Bletch. We must make read-only segments writable long enough to relocate them. */ const ElfW(Phdr) *ph; for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph) if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0) { caddr_t mapstart = ((caddr_t) l->l_addr + (ph->p_vaddr & ~(_dl_pagesize - 1))); caddr_t mapend = ((caddr_t) l->l_addr + ((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1) & ~(_dl_pagesize - 1))); if (__builtin_expect (__mprotect (mapstart, mapend - mapstart, PROT_READ|PROT_WRITE), 0) < 0) _dl_signal_error (errno, l->l_name, NULL, N_("\ cannot make segment writable for relocation")); } } { /* Do the actual relocation of the object's GOT and other data. */ /* String table object symbols. */ const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */ #define RESOLVE_MAP(ref, version, r_type) \ (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \ ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \ && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \ ? (++_dl_num_cache_relocations, \ (*ref) = l->l_lookup_cache.ret, \ l->l_lookup_cache.value) \ : ({ lookup_t _lr; \ int _tc = elf_machine_type_class (r_type); \ l->l_lookup_cache.type_class = _tc; \ l->l_lookup_cache.sym = (*ref); \ _lr = ((version) != NULL && (version)->hash != 0 \ ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \ l, (ref), scope, \ (version), _tc, 0) \ : _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), \ scope, _tc, 0)); \ l->l_lookup_cache.ret = (*ref); \ l->l_lookup_cache.value = _lr; })) \ : l) #define RESOLVE(ref, version, r_type) \ (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \ ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \ && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \ ? (++_dl_num_cache_relocations, \ (*ref) = l->l_lookup_cache.ret, \ l->l_lookup_cache.value) \ : ({ lookup_t _lr; \ int _tc = elf_machine_type_class (r_type); \ l->l_lookup_cache.type_class = _tc; \ l->l_lookup_cache.sym = (*ref); \ _lr = ((version) != NULL && (version)->hash != 0 \ ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, \ l, (ref), scope, \ (version), _tc, 0) \ : _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), \ scope, _tc, 0)); \ l->l_lookup_cache.ret = (*ref); \ l->l_lookup_cache.value = _lr; })) \ : l->l_addr) #include "dynamic-link.h" ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling); if (__builtin_expect (consider_profiling, 0)) { /* Allocate the array which will contain the already found relocations. If the shared object lacks a PLT (for example if it only contains lead function) the l_info[DT_PLTRELSZ] will be NULL. */ if (l->l_info[DT_PLTRELSZ] == NULL) _dl_fatal_printf ("%s: profiler found no PLTREL in object %s\n", _dl_argv[0] ?: "", l->l_name); l->l_reloc_result = (ElfW(Addr) *) calloc (sizeof (ElfW(Addr)), l->l_info[DT_PLTRELSZ]->d_un.d_val); if (l->l_reloc_result == NULL) _dl_fatal_printf ("\ %s: profiler out of memory shadowing PLTREL of %s\n", _dl_argv[0] ?: "", l->l_name); } } /* Mark the object so we know this work has been done. */ l->l_relocated = 1; /* DT_TEXTREL is now in level 2 and might phase out at some time. But we rewrite the DT_FLAGS entry to make testing easier and therefore it will be available at all time. */ if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0)) { /* Undo the protection change we made before relocating. */ const ElfW(Phdr) *ph; for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph) if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0) { caddr_t mapstart = ((caddr_t) l->l_addr + (ph->p_vaddr & ~(_dl_pagesize - 1))); caddr_t mapend = ((caddr_t) l->l_addr + ((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1) & ~(_dl_pagesize - 1))); extern unsigned char _dl_pf_to_prot[8]; int prot; if ((PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7) prot = _dl_pf_to_prot[ph->p_flags & (PF_R | PF_X)]; else { prot = 0; if (ph->p_flags & PF_R) prot |= PROT_READ; if (ph->p_flags & PF_X) prot |= PROT_EXEC; } if (__builtin_expect (__mprotect (mapstart, mapend - mapstart, prot), 0) < 0) _dl_signal_error (errno, l->l_name, NULL, N_("can't restore segment prot after reloc")); #ifdef CLEAR_CACHE CLEAR_CACHE (mapstart, mapend); #endif } } } void internal_function _dl_reloc_bad_type (struct link_map *map, unsigned int type, int plt) { extern const char _itoa_lower_digits[]; #define DIGIT(b) _itoa_lower_digits[(b) & 0xf]; /* XXX We cannot translate these messages. */ static const char msg[2][32] = { "unexpected reloc type 0x", "unexpected PLT reloc type 0x" }; char msgbuf[sizeof (msg[0])]; char *cp; cp = __stpcpy (msgbuf, msg[plt]); *cp++ = DIGIT (type >> 4); *cp = DIGIT (type); _dl_signal_error (0, map->l_name, NULL, msgbuf); }