diff options
Diffstat (limited to 'elf/do-lookup.h')
| -rw-r--r-- | elf/do-lookup.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/elf/do-lookup.h b/elf/do-lookup.h new file mode 100644 index 0000000000..1a833be83a --- /dev/null +++ b/elf/do-lookup.h @@ -0,0 +1,202 @@ +/* Look up a symbol in the loaded objects. + Copyright (C) 1995, 1996, 1997, 1998, 1999 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 Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#if VERSIONED +# define FCT do_lookup_versioned +# define ARG const struct r_found_version *const version, +#else +# define FCT do_lookup +# define ARG +#endif + +/* Inner part of the lookup functions. We return a value > 0 if we + found the symbol, the value 0 if nothing is found and < 0 if + something bad happened. */ +static inline int +FCT (const char *undef_name, unsigned long int hash, + const ElfW(Sym) *ref, struct sym_val *result, + struct r_scope_elem *scope, size_t i, const char *reference_name, + ARG struct link_map *skip, int reloc_type) +{ + struct link_map **list = scope->r_list; + size_t n = scope->r_nlist; + struct link_map *map; + + do + { + const ElfW(Sym) *symtab; + const char *strtab; + const ElfW(Half) *verstab; + ElfW(Symndx) symidx; + const ElfW(Sym) *sym; +#if ! VERSIONED + int num_versions = 0; + const ElfW(Sym) *versioned_sym = NULL; +#endif + + map = list[i]; + + /* Here come the extra test needed for `_dl_lookup_symbol_skip'. */ + if (skip != NULL && map == skip) + continue; + + /* Skip objects that could not be opened, which can occur in trace + mode. */ + if (map->l_opencount == 0) + continue; + + /* Don't search the executable when resolving a copy reloc. */ + if (elf_machine_lookup_noexec_p (reloc_type) + && map->l_type == lt_executable) + continue; + + /* Skip objects without symbol tables. */ + if (map->l_info[DT_SYMTAB] == NULL) + continue; + + /* Print some debugging info if wanted. */ + if (_dl_debug_symbols) + _dl_debug_message (1, "symbol=", undef_name, "; lookup in file=", + map->l_name[0] ? map->l_name : _dl_argv[0], + "\n", NULL); + + symtab = (const void *) map->l_info[DT_SYMTAB]->d_un.d_ptr; + strtab = (const void *) map->l_info[DT_STRTAB]->d_un.d_ptr; + verstab = map->l_versyms; + + /* Search the appropriate hash bucket in this object's symbol table + for a definition for the same symbol name. */ + for (symidx = map->l_buckets[hash % map->l_nbuckets]; + symidx != STN_UNDEF; + symidx = map->l_chain[symidx]) + { + sym = &symtab[symidx]; + + if (sym->st_value == 0 || /* No value. */ + (elf_machine_lookup_noplt_p (reloc_type) /* Reject PLT entry. */ + && sym->st_shndx == SHN_UNDEF)) + continue; + + if (ELFW(ST_TYPE) (sym->st_info) > STT_FUNC) + /* Ignore all but STT_NOTYPE, STT_OBJECT and STT_FUNC entries + since these are no code/data definitions. */ + continue; + + if (sym != ref && strcmp (strtab + sym->st_name, undef_name)) + /* Not the symbol we are looking for. */ + continue; + +#if VERSIONED + if (verstab == NULL) + { + /* We need a versioned system but haven't found any. If + this is the object which is referenced in the verneed + entry it is a bug in the library since a symbol must + not simply disappear. */ + if (version->filename != NULL + && _dl_name_match_p (version->filename, map)) + return -2; + /* Otherwise we accept the symbol. */ + } + else + { + /* We can match the version information or use the + default one if it is not hidden. */ + ElfW(Half) ndx = verstab[symidx] & 0x7fff; + if ((map->l_versions[ndx].hash != version->hash + || strcmp (map->l_versions[ndx].name, version->name)) + && (version->hidden || map->l_versions[ndx].hash + || (verstab[symidx] & 0x8000))) + /* It's not the version we want. */ + continue; + } +#else + /* No specific version is selected. When the object file + also does not define a version we have a match. + Otherwise we accept the default version, or in case there + is only one version defined, this one version. */ + if (verstab != NULL) + { + ElfW(Half) ndx = verstab[symidx] & 0x7fff; + if (ndx > 2) /* map->l_versions[ndx].hash != 0) */ + { + /* Don't accept hidden symbols. */ + if ((verstab[symidx] & 0x8000) == 0 && num_versions++ == 0) + /* No version so far. */ + versioned_sym = sym; + continue; + } + } +#endif + + /* There cannot be another entry for this symbol so stop here. */ + goto found_it; + } + + /* If we have seen exactly one versioned symbol while we are + looking for an unversioned symbol and the version is not the + default version we still accept this symbol since there are + no possible ambiguities. */ +#if VERSIONED + sym = NULL; +#else + sym = num_versions == 1 ? versioned_sym : NULL; +#endif + + if (sym != NULL) + { + found_it: + switch (ELFW(ST_BIND) (sym->st_info)) + { + case STB_GLOBAL: + /* Global definition. Just what we need. */ + result->s = sym; + result->m = map; + return 1; + case STB_WEAK: + /* Weak definition. Use this value if we don't find another. */ + if (! result->s) + { + result->s = sym; + result->m = map; + } + break; + default: + /* Local symbols are ignored. */ + break; + } + } + +#if VERSIONED + /* If this current map is the one mentioned in the verneed entry + and we have not found a weak entry, it is a bug. */ + if (symidx == STN_UNDEF && version->filename != NULL + && _dl_name_match_p (version->filename, map)) + return -1; +#endif + } + while (++i < n); + + /* We have not found anything until now. */ + return 0; +} + +#undef FCT +#undef ARG +#undef VERSIONED |