diff options
Diffstat (limited to 'elf/dl-lookup.c')
| -rw-r--r-- | elf/dl-lookup.c | 115 |
1 files changed, 67 insertions, 48 deletions
diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c index fdb076951d..e971929d0e 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 Free Software Foundation, Inc. + Copyright (C) 1995-2005, 2006, 2007 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 @@ -23,8 +23,9 @@ #include <string.h> #include <unistd.h> #include <ldsodefs.h> -#include "dl-hash.h" +#include <dl-hash.h> #include <dl-machine.h> +#include <sysdep-cancel.h> #include <bits/libc-lock.h> #include <tls.h> @@ -72,6 +73,16 @@ 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 @@ -91,11 +102,6 @@ add_dependency (struct link_map *undef_map, struct link_map *map) /* Make sure nobody can unload the object while we are at it. */ __rtld_lock_lock_recursive (GL(dl_load_lock)); - /* Don't create cross-reference between modules which are - dynamically loaded by the same dlopen() call. */ - if (undef_map->l_opencount == 0 && map->l_opencount == 0) - goto out; - /* Avoid references to objects which cannot be unloaded anyway. */ if (map->l_type != lt_loaded || (map->l_flags_1 & DF_1_NODELETE) != 0) @@ -107,14 +113,13 @@ add_dependency (struct link_map *undef_map, struct link_map *map) if (undef_map->l_type != lt_loaded || (undef_map->l_flags_1 & DF_1_NODELETE) != 0) { - ++map->l_opencount; map->l_flags_1 |= DF_1_NODELETE; goto out; } /* Determine whether UNDEF_MAP already has a reference to MAP. First look in the normal dependencies. */ - if (undef_map->l_searchlist.r_list != NULL) + if (undef_map->l_initfini != NULL) { list = undef_map->l_initfini; @@ -172,19 +177,6 @@ add_dependency (struct link_map *undef_map, struct link_map *map) if (__builtin_expect (act < undef_map->l_reldepsmax, 1)) undef_map->l_reldeps[undef_map->l_reldepsact++] = map; - if (map->l_searchlist.r_list != NULL) - /* And increment the counter in the referenced object. */ - ++map->l_opencount; - else - /* We have to bump the counts for all dependencies since so far - this object was only a normal or transitive dependency. - Now it might be closed with _dl_close() directly. */ - for (list = map->l_initfini; *list != NULL; ++list) - ++(*list)->l_opencount; - - /* As if it is opened through _dl_open. */ - ++map->l_direct_opencount; - /* Display information if we are debugging. */ if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0)) _dl_debug_printf ("\ @@ -209,14 +201,17 @@ add_dependency (struct link_map *undef_map, struct link_map *map) static void internal_function _dl_debug_bindings (const char *undef_name, struct link_map *undef_map, - const ElfW(Sym) **ref, struct r_scope_elem *symbol_scope[], - struct sym_val *value, + const ElfW(Sym) **ref, struct sym_val *value, const struct r_found_version *version, int type_class, int protected); /* Search loaded objects' symbol tables for a definition of the symbol - UNDEF_NAME, perhaps with a requested version for the symbol. */ + UNDEF_NAME, perhaps with a requested version for the symbol. + + We must never have calls to the audit functions inside this function + or in any function which gets called. If this would happen the audit + code might create a thread which can throw off all the scope locking. */ lookup_t internal_function _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, @@ -225,7 +220,8 @@ _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; @@ -233,23 +229,20 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, /* No other flag than DL_LOOKUP_ADD_DEPENDENCY is allowed if we look up a versioned symbol. */ - assert (version == NULL || flags == 0 || flags == DL_LOOKUP_ADD_DEPENDENCY); + assert (version == NULL || (flags & ~(DL_LOOKUP_ADD_DEPENDENCY)) == 0); size_t i = 0; if (__builtin_expect (skip_map != NULL, 0)) - { - /* Search the relevant loaded objects for a definition. */ - while ((*scope)->r_list[i] != skip_map) - ++i; - - assert (i < (*scope)->r_nlist); - } + /* Search the relevant loaded objects for a definition. */ + while ((*scope)->r_list[i] != skip_map) + ++i; /* 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; @@ -320,9 +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) @@ -345,16 +338,15 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map, && add_dependency (undef_map, current_value.m) < 0) /* Something went wrong. Perhaps the object we tried to reference was just removed. Try finding another definition. */ - return _dl_lookup_symbol_x (undef_name, undef_map, ref, - symbol_scope, version, type_class, - flags, skip_map); + return _dl_lookup_symbol_x (undef_name, undef_map, ref, symbol_scope, + version, type_class, flags, skip_map); /* The object is used. */ current_value.m->l_used = 1; if (__builtin_expect (GLRO(dl_debug_mask) & (DL_DEBUG_BINDINGS|DL_DEBUG_PRELINK), 0)) - _dl_debug_bindings (undef_name, undef_map, ref, symbol_scope, + _dl_debug_bindings (undef_name, undef_map, ref, ¤t_value, version, type_class, protected); *ref = current_value.s; @@ -371,6 +363,31 @@ _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]); @@ -386,8 +403,7 @@ _dl_setup_hash (struct link_map *map) static void internal_function _dl_debug_bindings (const char *undef_name, struct link_map *undef_map, - const ElfW(Sym) **ref, struct r_scope_elem *symbol_scope[], - struct sym_val *value, + const ElfW(Sym) **ref, struct sym_val *value, const struct r_found_version *version, int type_class, int protected) { @@ -395,11 +411,13 @@ _dl_debug_bindings (const char *undef_name, struct link_map *undef_map, if (GLRO(dl_debug_mask) & DL_DEBUG_BINDINGS) { - _dl_debug_printf ("binding file %s to %s: %s symbol `%s'", + _dl_debug_printf ("binding file %s [%lu] to %s [%lu]: %s symbol `%s'", (reference_name[0] ? reference_name : (rtld_progname ?: "<main program>")), + undef_map->l_ns, value->m->l_name[0] ? value->m->l_name : rtld_progname, + value->m->l_ns, protected ? "protected" : "normal", undef_name); if (version) _dl_debug_printf_c (" [%s]\n", version->name); @@ -416,9 +434,10 @@ _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); |