diff options
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/dl-lookup.c | 56 | ||||
| -rw-r--r-- | elf/dl-misc.c | 4 | ||||
| -rw-r--r-- | elf/do-lookup.h | 258 | ||||
| -rw-r--r-- | elf/dynamic-link.h | 4 | ||||
| -rw-r--r-- | elf/elf.h | 8 |
5 files changed, 208 insertions, 122 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index 5a7bed16e5..7cfcc620a7 100644 --- a/elf/dl-lookup.c +++ b/elf/dl-lookup.c @@ -1,5 +1,5 @@ /* Look up a symbol in the loaded objects. - Copyright (C) 1995-2002, 2003, 2004, 2005 Free Software Foundation, Inc. + Copyright (C) 1995-2005, 2006 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 @@ -72,6 +72,16 @@ struct sym_val #include "do-lookup.h" +static uint_fast32_t +dl_new_hash (const char *s) +{ + uint_fast32_t h = 5381; + for (unsigned char c = *s; c != '\0'; c = *++s) + h = h * 33 + c; + return h & 0xffffffff; +} + + /* Add extra dependency on MAP to UNDEF_MAP. */ static int internal_function @@ -206,7 +216,8 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, const struct r_found_version *version, int type_class, int flags, struct link_map *skip_map) { - const unsigned long int hash = _dl_elf_hash (undef_name); + const uint_fast32_t new_hash = dl_new_hash (undef_name); + unsigned long int old_hash = 0xffffffff; struct sym_val current_value = { NULL, NULL }; struct r_scope_elem **scope = symbol_scope; @@ -229,8 +240,9 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, /* Search the relevant loaded objects for a definition. */ for (size_t start = i; *scope != NULL; start = 0, ++scope) { - int res = do_lookup_x (undef_name, hash, *ref, ¤t_value, *scope, - start, version, flags, skip_map, type_class); + int res = do_lookup_x (undef_name, new_hash, &old_hash, *ref, + ¤t_value, *scope, start, version, flags, + skip_map, type_class); if (res > 0) break; @@ -301,9 +313,9 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, struct sym_val protected_value = { NULL, NULL }; for (scope = symbol_scope; *scope != NULL; i = 0, ++scope) - if (do_lookup_x (undef_name, hash, *ref, &protected_value, - *scope, i, version, flags, skip_map, - ELF_RTYPE_CLASS_PLT) != 0) + if (do_lookup_x (undef_name, new_hash, &old_hash, *ref, + &protected_value, *scope, i, version, flags, + skip_map, ELF_RTYPE_CLASS_PLT) != 0) break; if (protected_value.s != NULL && protected_value.m != undef_map) @@ -352,6 +364,31 @@ _dl_setup_hash (struct link_map *map) Elf_Symndx *hash; Elf_Symndx nchain; + if (__builtin_expect (map->l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + + DT_THISPROCNUM + DT_VERSIONTAGNUM + + DT_EXTRANUM + DT_VALNUM] != NULL, 1)) + { + Elf32_Word *hash32 + = (void *) D_PTR (map, l_info[DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + + DT_THISPROCNUM + DT_VERSIONTAGNUM + + DT_EXTRANUM + DT_VALNUM]); + map->l_nbuckets = *hash32++; + Elf32_Word symbias = *hash32++; + Elf32_Word bitmask_nwords = *hash32++; + /* Must be a power of two. */ + assert ((bitmask_nwords & (bitmask_nwords - 1)) == 0); + map->l_gnu_bitmask_idxbits = bitmask_nwords - 1; + map->l_gnu_shift = *hash32++; + + map->l_gnu_bitmask = (ElfW(Addr) *) hash32; + hash32 += __ELF_NATIVE_CLASS / 32 * bitmask_nwords; + + map->l_gnu_buckets = hash32; + hash32 += map->l_nbuckets; + map->l_gnu_chain_zero = hash32 - symbias; + return; + } + if (!map->l_info[DT_HASH]) return; hash = (void *) D_PTR (map, l_info[DT_HASH]); @@ -399,9 +436,10 @@ _dl_debug_bindings (const char *undef_name, struct link_map *undef_map, || GLRO(dl_trace_prelink_map) == GL(dl_ns)[LM_ID_BASE]._ns_loaded) && undef_map != GL(dl_ns)[LM_ID_BASE]._ns_loaded) { - const unsigned long int hash = _dl_elf_hash (undef_name); + const uint_fast32_t new_hash = dl_new_hash (undef_name); + unsigned long int old_hash = 0xffffffff; - do_lookup_x (undef_name, hash, *ref, &val, + do_lookup_x (undef_name, new_hash, &old_hash, *ref, &val, undef_map->l_local_scope[0], 0, version, 0, NULL, type_class); diff --git a/elf/dl-misc.c b/elf/dl-misc.c index 08d64956b8..6da1e2e4aa 100644 --- a/elf/dl-misc.c +++ b/elf/dl-misc.c @@ -1,5 +1,5 @@ /* Miscellaneous support functions for dynamic linker - Copyright (C) 1997-2002, 2003, 2004 Free Software Foundation, Inc. + Copyright (C) 1997-2002, 2003, 2004, 2006 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 @@ -308,7 +308,7 @@ _dl_dprintf (int fd, const char *fmt, ...) /* Test whether given NAME matches any of the names of the given object. */ int internal_function -_dl_name_match_p (const char *name, struct link_map *map) +_dl_name_match_p (const char *name, const struct link_map *map) { if (strcmp (name, map->l_name) == 0) return 1; diff --git a/elf/do-lookup.h b/elf/do-lookup.h index 7b62b0feec..f40ab9d8d4 100644 --- a/elf/do-lookup.h +++ b/elf/do-lookup.h @@ -17,32 +17,29 @@ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ + /* 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 int __attribute_noinline__ -do_lookup_x (const char *undef_name, unsigned long int hash, - const ElfW(Sym) *ref, struct sym_val *result, - struct r_scope_elem *scope, size_t i, +do_lookup_x (const char *undef_name, uint_fast32_t new_hash, + unsigned long int *old_hash, const ElfW(Sym) *ref, + struct sym_val *result, struct r_scope_elem *scope, size_t i, const struct r_found_version *const version, int flags, struct link_map *skip, int type_class) { 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; + /* These variables are used in the nested function. */ Elf_Symndx symidx; - const ElfW(Sym) *sym; int num_versions = 0; const ElfW(Sym) *versioned_sym = NULL; - map = list[i]->l_real; + const struct link_map *map = list[i]->l_real; /* Here come the extra test needed for `_dl_lookup_symbol_skip'. */ if (map == skip) @@ -63,109 +60,158 @@ do_lookup_x (const char *undef_name, unsigned long int hash, map->l_name[0] ? map->l_name : rtld_progname, map->l_ns); - symtab = (const void *) D_PTR (map, l_info[DT_SYMTAB]); - strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); - verstab = map->l_versyms; + /* If the hash table is empty there is nothing to do here. */ + if (map->l_nbuckets == 0) + continue; - /* 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]; - - assert (ELF_RTYPE_CLASS_PLT == 1); - if ((sym->st_value == 0 /* No value. */ -#ifdef USE_TLS - && ELFW(ST_TYPE) (sym->st_info) != STT_TLS -#endif - ) - || (type_class & (sym->st_shndx == SHN_UNDEF))) - continue; - - if (ELFW(ST_TYPE) (sym->st_info) > STT_FUNC -#ifdef USE_TLS - && ELFW(ST_TYPE) (sym->st_info) != STT_TLS -#endif - ) - /* Ignore all but STT_NOTYPE, STT_OBJECT and STT_FUNC - entries (and STT_TLS if TLS is supported) 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 (version != NULL) - { - if (__builtin_expect (verstab == NULL, 0)) - { - /* We need a versioned symbol 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. - - It would also be a bug in the object since it means that - the list of required versions is incomplete and so the - tests in dl-version.c haven't found a problem.*/ - assert (version->filename == NULL - || ! _dl_name_match_p (version->filename, map)); - - /* 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. There are two ways we - can got here: + /* The tables for this map. */ + const ElfW(Sym) *symtab = (const void *) D_PTR (map, l_info[DT_SYMTAB]); + const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); + + + /* Nested routine to check whether the symbol matches. */ + const ElfW(Sym) * + __attribute_noinline__ + check_match (const ElfW(Sym) *sym) + { + assert (ELF_RTYPE_CLASS_PLT == 1); + if (__builtin_expect ((sym->st_value == 0 /* No value. */ + && ELFW(ST_TYPE) (sym->st_info) != STT_TLS) + || (type_class & (sym->st_shndx == SHN_UNDEF)), + 0)) + return NULL; + + if (__builtin_expect (ELFW(ST_TYPE) (sym->st_info) > STT_FUNC + && ELFW(ST_TYPE) (sym->st_info) != STT_TLS, 0)) + /* Ignore all but STT_NOTYPE, STT_OBJECT and STT_FUNC + entries (and STT_TLS if TLS is supported) since these + are no code/data definitions. */ + return NULL; + + if (sym != ref && strcmp (strtab + sym->st_name, undef_name)) + /* Not the symbol we are looking for. */ + return NULL; + + const ElfW(Half) *verstab = map->l_versyms; + if (version != NULL) + { + if (__builtin_expect (verstab == NULL, 0)) + { + /* We need a versioned symbol 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. + + It would also be a bug in the object since it means that + the list of required versions is incomplete and so the + tests in dl-version.c haven't found a problem.*/ + assert (version->filename == NULL + || ! _dl_name_match_p (version->filename, map)); - - a binary which does not include versioning information - is loaded + /* 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. */ + return NULL; + } + } + else + { + /* No specific version is selected. There are two ways we + can got here: - - dlsym() instead of dlvsym() is used to get a symbol which - might exist in more than one form + - a binary which does not include versioning information + is loaded - If the library does not provide symbol version - information there is no problem at at: we simply use the - symbol if it is defined. + - dlsym() instead of dlvsym() is used to get a symbol which + might exist in more than one form - These two lookups need to be handled differently if the - library defines versions. In the case of the old - unversioned application the oldest (default) version - should be used. In case of a dlsym() call the latest and - public interface should be returned. */ - if (verstab != NULL) + If the library does not provide symbol version information + there is no problem at at: we simply use the symbol if it + is defined. + + These two lookups need to be handled differently if the + library defines versions. In the case of the old + unversioned application the oldest (default) version + should be used. In case of a dlsym() call the latest and + public interface should be returned. */ + if (verstab != NULL) + { + if ((verstab[symidx] & 0x7fff) + >= ((flags & DL_LOOKUP_RETURN_NEWEST) ? 2 : 3)) + { + /* Don't accept hidden symbols. */ + if ((verstab[symidx] & 0x8000) == 0 + && num_versions++ == 0) + /* No version so far. */ + versioned_sym = sym; + + return NULL; + } + } + } + + /* There cannot be another entry for this symbol so stop here. */ + return sym; + } + + const ElfW(Sym) *sym; + const ElfW(Addr) *bitmask = map->l_gnu_bitmask; + if (__builtin_expect (bitmask != NULL, 1)) + { + ElfW(Addr) bitmask_word + = bitmask[(new_hash / __ELF_NATIVE_CLASS) + & map->l_gnu_bitmask_idxbits]; + + unsigned int hashbit1 = new_hash & (__ELF_NATIVE_CLASS - 1); + unsigned int hashbit2 = ((new_hash >> map->l_gnu_shift) + & (__ELF_NATIVE_CLASS - 1)); + + if (__builtin_expect ((bitmask_word >> hashbit1) + & (bitmask_word >> hashbit2) & 1, 0)) + { + Elf32_Word bucket = map->l_gnu_buckets[new_hash + % map->l_nbuckets]; + if (bucket != 0) { - if ((verstab[symidx] & 0x7fff) - >= ((flags & DL_LOOKUP_RETURN_NEWEST) ? 2 : 3)) - { - /* Don't accept hidden symbols. */ - if ((verstab[symidx] & 0x8000) == 0 - && num_versions++ == 0) - /* No version so far. */ - versioned_sym = sym; + const Elf32_Word *hasharr = &map->l_gnu_chain_zero[bucket]; - continue; - } + do + if ((*hasharr & ~1u) == (new_hash & ~1u)) + { + symidx = hasharr - map->l_gnu_chain_zero; + sym = check_match (&symtab[symidx]); + if (sym != NULL) + goto found_it; + } + while ((*hasharr++ & 1u) == 0); } } + } + else + { + if (*old_hash == 0xffffffff) + *old_hash = _dl_elf_hash (undef_name); - /* There cannot be another entry for this symbol so stop here. */ - goto found_it; + /* Use the old SysV-style hash table. Search the appropriate + hash bucket in this object's symbol table for a definition + for the same symbol name. */ + for (symidx = map->l_buckets[*old_hash % map->l_nbuckets]; + symidx != STN_UNDEF; + symidx = map->l_chain[symidx]) + { + sym = check_match (&symtab[symidx]); + if (sym != NULL) + goto found_it; + } } /* If we have seen exactly one versioned symbol while we are @@ -186,7 +232,7 @@ do_lookup_x (const char *undef_name, unsigned long int hash, if (! result->s) { result->s = sym; - result->m = map; + result->m = (struct link_map *) map; } break; } @@ -194,7 +240,7 @@ do_lookup_x (const char *undef_name, unsigned long int hash, case STB_GLOBAL: /* Global definition. Just what we need. */ result->s = sym; - result->m = map; + result->m = (struct link_map *) map; return 1; default: /* Local symbols are ignored. */ @@ -213,7 +259,3 @@ do_lookup_x (const char *undef_name, unsigned long int hash, /* We have not found anything until now. */ return 0; } - -#undef FCT -#undef ARG -#undef VERSIONED diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h index cf0d223c45..7eb9a36137 100644 --- a/elf/dynamic-link.h +++ b/elf/dynamic-link.h @@ -1,5 +1,5 @@ /* Inline functions for dynamic linking. - Copyright (C) 1995-2002, 2003, 2004, 2005 Free Software Foundation, Inc. + Copyright (C) 1995-2005, 2006 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 @@ -143,6 +143,8 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp) # endif ADJUST_DYN_INFO (DT_JMPREL); ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM)); + ADJUST_DYN_INFO (DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + DT_THISPROCNUM + + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM); # undef ADJUST_DYN_INFO assert (cnt <= DL_RO_DYN_TEMP_CNT); } @@ -329,7 +329,8 @@ typedef struct #define SHT_GROUP 17 /* Section group */ #define SHT_SYMTAB_SHNDX 18 /* Extended section indeces */ #define SHT_NUM 19 /* Number of defined types. */ -#define SHT_LOOS 0x60000000 /* Start OS-specific */ +#define SHT_LOOS 0x60000000 /* Start OS-specific. */ +#define SHT_GNU_HASH 0x6ffffff6 /* GNU-style hash table. */ #define SHT_GNU_LIBLIST 0x6ffffff7 /* Prelink library list */ #define SHT_CHECKSUM 0x6ffffff8 /* Checksum for DSO content. */ #define SHT_LOSUNW 0x6ffffffa /* Sun-specific low bound. */ @@ -699,6 +700,9 @@ typedef struct If any adjustment is made to the ELF object after it has been built these entries will need to be adjusted. */ #define DT_ADDRRNGLO 0x6ffffe00 +#define DT_GNU_HASH 0x6ffffef5 /* GNU-style hash table. */ +#define DT_TLSDESC_PLT 0x6ffffef6 +#define DT_TLSDESC_GOT 0x6ffffef7 #define DT_GNU_CONFLICT 0x6ffffef8 /* Start of conflict section */ #define DT_GNU_LIBLIST 0x6ffffef9 /* Library list */ #define DT_CONFIG 0x6ffffefa /* Configuration information. */ @@ -709,7 +713,7 @@ typedef struct #define DT_SYMINFO 0x6ffffeff /* Syminfo table. */ #define DT_ADDRRNGHI 0x6ffffeff #define DT_ADDRTAGIDX(tag) (DT_ADDRRNGHI - (tag)) /* Reverse order! */ -#define DT_ADDRNUM 10 +#define DT_ADDRNUM 11 /* The versioning entry types. The next are defined as part of the GNU extension. */ |