/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2007 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #pragma ident "%Z%%M% %I% %E% SMI" /* * ELFCLASS specific code for elfedit, built once for each class */ #include #include #include #include #include #include #include #include "msg.h" #include "_elfedit.h" /* * Look up the elfedit_symtab_t that corresponds to the symbol table * referenced by the sh_link field of the given auxiliary section. * * entry: * obj_state - Partially constructed object state from * elfedit_init_obj_state(). * auxsec - Section that is associated with the symbol table section * * exit: * Returns the pointer to the elfedit_symtab_t entry that is * referenced by the auxiliary section. If not found, * outputs a debug message, and returns NULL. */ static elfedit_symtab_t * get_symtab(elfedit_obj_state_t *obj_state, elfedit_section_t *auxsec) { elfedit_symtab_t *symtab = obj_state->os_symtab; Word sh_link = auxsec->sec_shdr->sh_link; Word i; for (i = 0; i < obj_state->os_symtabnum; i++, symtab++) if (symtab->symt_shndx == sh_link) return (symtab); /* * If we don't return above, it doesn't reference a valid * symbol table. Issue warning. */ elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_AUX_LINK), EC_WORD(auxsec->sec_shndx), auxsec->sec_name, EC_WORD(sh_link)); return (NULL); } /* * Fill in state.elf.obj_state with a a dynamically allocated * elfedit_obj_state_t struct of the appropriate ELFCLASS. * This pre-chewed form is fed to each command, reducing the amount * of ELF boilerplate code each command needs to contain. * * entry: * file - Name of file to process * fd - Descriptor of open file which has been successfully * processed by elf_begin(). * elf - Elf handle returned by elf_begin * * exit: * An elfedit_obj_state_t struct of the appropriate ELFCLASS has * been dynamically allocated, and state.elf.obj_state references it. * On failure, this routine does not return to the caller. * * note: The resulting elfedit_obj_state_t is allocated from a single * piece of memory, such that a single call to free() suffices * to release it as well as any memory it references. */ #ifdef _ELF64 void elfedit64_init_obj_state(const char *file, int fd, Elf *elf) #else void elfedit32_init_obj_state(const char *file, int fd, Elf *elf) #endif { #define INITIAL_SYMTABNDX_ALLOC 5 /* * This macro is used to call functions from libelf, all of which * return NULL for failure and something else for success. On error, * libelf_fail_name is set and execution jumps to the libelf_failure * label for handling. Otherwise, the results of the call are ready * for use by the caller. */ #define LIBELF(_libelf_expr, _name) \ if ((_libelf_expr) == NULL) { \ libelf_fail_name = _name; \ goto libelf_failure; \ } const char *libelf_fail_name; /* Used for LIBELF errors */ Elf_Scn *scn; Elf_Data *data; uint_t ndx; size_t len, os_size, secarr_size; char *names = 0; size_t names_len; elfedit_section_t *_cache; elfedit_obj_state_t tstate; elfedit_obj_state_t *obj_state = NULL; Word *symtabndx = NULL; Word symtabndx_size = 0; elfedit_symtab_t *symtab; tstate.os_file = file; tstate.os_fd = fd; tstate.os_elf = elf; tstate.os_dynndx = SHN_UNDEF; tstate.os_symtabnum = 0; LIBELF(tstate.os_ehdr = elf_getehdr(tstate.os_elf), MSG_ORIG(MSG_ELF_GETEHDR)) /* Program header array count and address */ LIBELF(elf_getphnum(tstate.os_elf, &tstate.os_phnum), MSG_ORIG(MSG_ELF_GETPHNUM)) if (tstate.os_phnum > 0) { LIBELF((tstate.os_phdr = elf_getphdr(tstate.os_elf)), MSG_ORIG(MSG_ELF_GETPHDR)) } else { tstate.os_phdr = NULL; } LIBELF(elf_getshnum(tstate.os_elf, &tstate.os_shnum), MSG_ORIG(MSG_ELF_GETSHNUM)) /* * Obtain the .shstrtab data buffer to provide the required section * name strings. */ LIBELF(elf_getshstrndx(tstate.os_elf, &tstate.os_shstrndx), MSG_ORIG(MSG_ELF_GETSHSTRNDX)) LIBELF((scn = elf_getscn(tstate.os_elf, tstate.os_shstrndx)), MSG_ORIG(MSG_ELF_GETSCN)) LIBELF((data = elf_getdata(scn, NULL)), MSG_ORIG(MSG_ELF_GETDATA)) names = data->d_buf; names_len = (names == NULL) ? 0 : data->d_size; /* * Count the number of symbol tables and capture their indexes. * Find the dynamic section. */ for (ndx = 1, scn = NULL; scn = elf_nextscn(tstate.os_elf, scn); ndx++) { Shdr *shdr; LIBELF(shdr = elf_getshdr(scn), MSG_ORIG(MSG_ELF_GETSHDR)); switch (shdr->sh_type) { case SHT_DYNAMIC: /* Save index of dynamic section for use below */ tstate.os_dynndx = ndx; break; case SHT_SYMTAB: case SHT_DYNSYM: case SHT_SUNW_LDYNSYM: if (symtabndx_size <= tstate.os_symtabnum) { symtabndx_size = (symtabndx_size == 0) ? INITIAL_SYMTABNDX_ALLOC : (symtabndx_size * 2); symtabndx = elfedit_realloc( MSG_INTL(MSG_ALLOC_SYMTABOS), symtabndx, symtabndx_size * sizeof (symtabndx[0])); } symtabndx[tstate.os_symtabnum++] = ndx; break; } } /* * Allocate space to hold the state. We allocate space for everything * in one chunk to make releasing it easy: * (1) elfedit_obj_state_t struct * (2) The array of elfedit_section_t items referenced from * the elfedit_obj_state_t struct. * (3) The array of elfedit_symtab_t items referenced from * the elfedit_obj_state_t struct. * (4) The file name. * * Note that we round up the size of (1) and (2) to a double boundary * to ensure proper alignment of (2) and (3). (4) can align on any * boundary. */ os_size = S_DROUND(sizeof (tstate)); secarr_size = (tstate.os_shnum * sizeof (elfedit_section_t)); secarr_size = S_DROUND(secarr_size); len = strlen(tstate.os_file) + 1; obj_state = elfedit_malloc(MSG_INTL(MSG_ALLOC_OBJSTATE), os_size + secarr_size + (tstate.os_symtabnum * sizeof (elfedit_symtab_t)) + len); *obj_state = tstate; /*LINTED E_BAD_PTR_CAST_ALIGN*/ obj_state->os_secarr = (elfedit_section_t *) ((char *)obj_state + os_size); if (obj_state->os_symtabnum == 0) obj_state->os_symtab = NULL; else /*LINTED E_BAD_PTR_CAST_ALIGN*/ obj_state->os_symtab = (elfedit_symtab_t *) ((char *)obj_state->os_secarr + secarr_size); obj_state->os_file = (char *)(obj_state->os_symtab + tstate.os_symtabnum); (void) strncpy((char *)obj_state->os_file, tstate.os_file, len); /* * Fill in obj_state->os_secarr with information for each section. * At the same time, fill in obj_state->os_symtab with the symbol * table related data. */ bzero(obj_state->os_secarr, sizeof (obj_state->os_secarr[0])); _cache = obj_state->os_secarr; LIBELF(scn = elf_getscn(tstate.os_elf, 0), MSG_ORIG(MSG_ELF_GETSCN)); _cache->sec_scn = scn; LIBELF(_cache->sec_shdr = elf_getshdr(scn), MSG_ORIG(MSG_ELF_GETSHDR)); _cache->sec_name = (_cache->sec_shdr->sh_name < names_len) ? (names + _cache->sec_shdr->sh_name) : MSG_INTL(MSG_UNKNOWNSECNAM); _cache++; if (obj_state->os_symtab != NULL) { bzero(obj_state->os_symtab, sizeof (obj_state->os_symtab[0]) * obj_state->os_symtabnum); for (ndx = 0; ndx < obj_state->os_symtabnum; ndx++) obj_state->os_symtab[ndx].symt_shndx = symtabndx[ndx]; free(symtabndx); } for (ndx = 1, scn = NULL; scn = elf_nextscn(tstate.os_elf, scn); ndx++, _cache++) { _cache->sec_shndx = ndx; _cache->sec_scn = scn; LIBELF(_cache->sec_shdr = elf_getshdr(scn), MSG_ORIG(MSG_ELF_GETSHDR)) _cache->sec_data = elf_getdata(scn, NULL); _cache->sec_name = (_cache->sec_shdr->sh_name < names_len) ? (names + _cache->sec_shdr->sh_name) : MSG_INTL(MSG_UNKNOWNSECNAM); switch (_cache->sec_shdr->sh_type) { case SHT_SYMTAB_SHNDX: symtab = get_symtab(obj_state, _cache); symtab->symt_xshndx = ndx; break; case SHT_SUNW_syminfo: symtab = get_symtab(obj_state, _cache); symtab->symt_syminfo = ndx; break; case SHT_SUNW_versym: symtab = get_symtab(obj_state, _cache); symtab->symt_versym = ndx; break; } } /* * Sanity check the symbol tables, and discard any auxiliary * sections without enough elements. */ symtab = obj_state->os_symtab; for (ndx = 0; ndx < obj_state->os_symtabnum; ndx++, symtab++) { elfedit_section_t *symsec; Word symsec_cnt, aux_cnt; symsec = &obj_state->os_secarr[symtab->symt_shndx]; symsec_cnt = symsec->sec_shdr->sh_size / sizeof (Sym); /* Extended section indexes */ if (symtab->symt_xshndx != SHN_UNDEF) { _cache = &obj_state->os_secarr[symtab->symt_xshndx]; aux_cnt = _cache->sec_shdr->sh_size / sizeof (Word); if (symsec_cnt > aux_cnt) elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_AUX_SIZE), EC_WORD(ndx), _cache->sec_name, EC_WORD(aux_cnt), EC_WORD(symsec->sec_shndx), symsec->sec_name, EC_WORD(aux_cnt)); } /* Syminfo */ if (symtab->symt_syminfo != SHN_UNDEF) { _cache = &obj_state->os_secarr[symtab->symt_syminfo]; aux_cnt = _cache->sec_shdr->sh_size / sizeof (Syminfo); if (symsec_cnt > aux_cnt) elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_AUX_SIZE), EC_WORD(ndx), _cache->sec_name, EC_WORD(aux_cnt), EC_WORD(symsec->sec_shndx), symsec->sec_name, EC_WORD(aux_cnt)); } /* Versym */ if (symtab->symt_versym != SHN_UNDEF) { _cache = &obj_state->os_secarr[symtab->symt_versym]; aux_cnt = _cache->sec_shdr->sh_size / sizeof (Versym); if (symsec_cnt > aux_cnt) elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_AUX_SIZE), EC_WORD(ndx), _cache->sec_name, EC_WORD(aux_cnt), EC_WORD(symsec->sec_shndx), symsec->sec_name, EC_WORD(aux_cnt)); } } /* * If this object has a dynsym section with a FLAGS_1 field, * then set the DF_1_EDITED bit. elfedit allows changes that * can break the resulting program, so knowing that a file was * edited can be helpful when encountering a core file or other * unexpected failure in the field. A single bit can't tell you * what was changed, but it will alert you to the possibility that * some additional questions might be in order. */ if (obj_state->os_dynndx != SHN_UNDEF) { Word i; Word numdyn; elfedit_section_t *dynsec; elfedit_dyn_elt_t flags_1_elt; elfedit_dyn_elt_t null_elt; Dyn *dyn; dynsec = &obj_state->os_secarr[obj_state->os_dynndx]; dyn = (Dyn *) dynsec->sec_data->d_buf; numdyn = dynsec->sec_shdr->sh_size / dynsec->sec_shdr->sh_entsize; elfedit_dyn_elt_init(&flags_1_elt); elfedit_dyn_elt_init(&null_elt); for (i = 0; i < numdyn; i++) { switch (dyn[i].d_tag) { case DT_NULL: /* * Remember state of the first DT_NULL. If there * are more than one (i.e. the first one is not * in the final spot), and there is no flags1, * then we will turn the first one into a * DT_FLAGS_1. */ if (!null_elt.dn_seen) elfedit_dyn_elt_save(&null_elt, i, &dyn[i]); break; case DT_FLAGS_1: elfedit_dyn_elt_save(&flags_1_elt, i, &dyn[i]); break; } } /* If don't have a flags1 field, can we make one from a NULL? */ if (!flags_1_elt.dn_seen && null_elt.dn_seen && (null_elt.dn_ndx < (numdyn - 1))) { elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_NULL2DYNFL1), EC_WORD(obj_state->os_dynndx), dynsec->sec_name, EC_WORD(null_elt.dn_ndx)); flags_1_elt.dn_seen = 1; flags_1_elt.dn_ndx = null_elt.dn_ndx; flags_1_elt.dn_dyn.d_tag = DT_FLAGS_1; flags_1_elt.dn_dyn.d_un.d_val = 0; } /* * If there is a flags 1 field, add the edit flag if * it is not present, and report it's presence otherwise. */ if (flags_1_elt.dn_seen) { if (flags_1_elt.dn_dyn.d_un.d_val & DF_1_EDITED) { elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_SEEDYNFLG), EC_WORD(obj_state->os_dynndx), dynsec->sec_name, EC_WORD(flags_1_elt.dn_ndx)); } else { elfedit_msg(ELFEDIT_MSG_DEBUG, MSG_INTL(MSG_DEBUG_ADDDYNFLG), EC_WORD(obj_state->os_dynndx), dynsec->sec_name, EC_WORD(flags_1_elt.dn_ndx)); flags_1_elt.dn_dyn.d_un.d_val |= DF_1_EDITED; dyn[flags_1_elt.dn_ndx] = flags_1_elt.dn_dyn; elfedit_modified_data(dynsec); } } } #ifdef _ELF64 state.elf.obj_state.s64 = obj_state; #else state.elf.obj_state.s32 = obj_state; #endif return; libelf_failure: /* * Control comes here if there is an error with LIBELF. * * entry: * libelf_fail_name - Name of failing libelf function * tstate.os_file - Name of ELF file being processed * tstate.os_fd - Descriptor of open ELF file * * exit: * - dynamic memory is released if necessary * - The error issued */ if (obj_state != NULL) free(obj_state); (void) close(tstate.os_fd); elfedit_elferr(tstate.os_file, libelf_fail_name); #undef LIBELF_FAILURE #undef INITIAL_SYMTABNDX_ALLOC }