/* Look up a symbol in the loaded objects.
- MIPS/Linux version - this is identical to the common version, but
- because it is in sysdeps/mips, it gets sysdeps/mips/do-lookup.h.
- Using <do-lookup.h> instead of "do-lookup.h" would work too.
-
- Copyright (C) 1995-2005, 2006, 2007 Free Software Foundation, Inc.
+ MIPS/Linux version - special handling of non-PIC undefined symbol rules.
+ Copyright (C) 1995-2005, 2006, 2007, 2009 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
#endif
-/* The actual lookup code. */
-#include "do-lookup.h"
+/* 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, 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 *undef_map)
+{
+ size_t n = scope->r_nlist;
+ /* Make sure we read the value before proceeding. Otherwise we
+ might use r_list pointing to the initial scope and r_nlist being
+ the value after a resize. That is the only path in dl-open.c not
+ protected by GSCOPE. A read barrier here might be to expensive. */
+ __asm volatile ("" : "+r" (n), "+m" (scope->r_list));
+ struct link_map **list = scope->r_list;
+
+ do
+ {
+ /* These variables are used in the nested function. */
+ Elf_Symndx symidx;
+ int num_versions = 0;
+ const ElfW(Sym) *versioned_sym = NULL;
+
+ const struct link_map *map = list[i]->l_real;
+
+ /* Here come the extra test needed for `_dl_lookup_symbol_skip'. */
+ if (map == skip)
+ continue;
+
+ /* Don't search the executable when resolving a copy reloc. */
+ if ((type_class & ELF_RTYPE_CLASS_COPY) && map->l_type == lt_executable)
+ continue;
+
+ /* Do not look into objects which are going to be removed. */
+ if (map->l_removed)
+ continue;
+
+ /* Print some debugging info if wanted. */
+ if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_SYMBOLS, 0))
+ _dl_debug_printf ("symbol=%s; lookup in file=%s [%lu]\n",
+ undef_name,
+ map->l_name[0] ? map->l_name : rtld_progname,
+ map->l_ns);
+
+ /* If the hash table is empty there is nothing to do here. */
+ if (map->l_nbuckets == 0)
+ continue;
+
+ /* 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)
+ {
+ unsigned int stt = ELFW(ST_TYPE) (sym->st_info);
+ assert (ELF_RTYPE_CLASS_PLT == 1);
+ /* The semantics of zero/non-zero values of undefined symbols
+ differs depending on whether the non-PIC ABI is in use.
+ Under the non-PIC ABI, a non-zero value indicates that
+ there is an address reference to the symbol and thus it
+ must always be resolved (except when resolving a jump slot
+ relocation) to the PLT entry whose address is provided as
+ the symbol's value; a zero value indicates that this
+ canonical-address behaviour is not required. Yet under the
+ classic MIPS psABI, a zero value indicates that there is an
+ address reference to the function and the dynamic linker
+ must resolve the symbol immediately upon loading. To avoid
+ conflict, symbols for which the dynamic linker must assume
+ the non-PIC ABI semantics are marked with the STO_MIPS_PLT
+ flag. */
+ if (__builtin_expect ((sym->st_value == 0 /* No value. */
+ && stt != STT_TLS)
+ || (sym->st_shndx == SHN_UNDEF
+ && !(sym->st_other & STO_MIPS_PLT))
+ || (type_class & (sym->st_shndx == SHN_UNDEF)),
+ 0))
+ return NULL;
+
+ /* Ignore all but STT_NOTYPE, STT_OBJECT, STT_FUNC,
+ STT_COMMON, STT_TLS, and STT_GNU_IFUNC since these are no
+ code/data definitions. */
+#define ALLOWED_STT \
+ ((1 << STT_NOTYPE) | (1 << STT_OBJECT) | (1 << STT_FUNC) \
+ | (1 << STT_COMMON) | (1 << STT_TLS) | (1 << STT_GNU_IFUNC))
+ if (__builtin_expect (((1 << stt) & ALLOWED_STT) == 0, 0))
+ 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));
+
+ /* 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:
+
+ - a binary which does not include versioning information
+ is loaded
+
+ - dlsym() instead of dlvsym() is used to get a symbol which
+ might exist in more than one form
+
+ 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)
+ {
+ const Elf32_Word *hasharr = &map->l_gnu_chain_zero[bucket];
+
+ do
+ if (((*hasharr ^ new_hash) >> 1) == 0)
+ {
+ symidx = hasharr - map->l_gnu_chain_zero;
+ sym = check_match (&symtab[symidx]);
+ if (sym != NULL)
+ goto found_it;
+ }
+ while ((*hasharr++ & 1u) == 0);
+ }
+ }
+ /* No symbol found. */
+ symidx = SHN_UNDEF;
+ }
+ else
+ {
+ if (*old_hash == 0xffffffff)
+ *old_hash = _dl_elf_hash (undef_name);
+
+ /* 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
+ looking for an unversioned symbol and the version is not the
+ default version we still accept this symbol since there are
+ no possible ambiguities. */
+ sym = num_versions == 1 ? versioned_sym : NULL;
+
+ if (sym != NULL)
+ {
+ found_it:
+ switch (__builtin_expect (ELFW(ST_BIND) (sym->st_info), STB_GLOBAL))
+ {
+ case STB_WEAK:
+ /* Weak definition. Use this value if we don't find another. */
+ if (__builtin_expect (GLRO(dl_dynamic_weak), 0))
+ {
+ if (! result->s)
+ {
+ result->s = sym;
+ result->m = (struct link_map *) map;
+ }
+ break;
+ }
+ /* FALLTHROUGH */
+ case STB_GLOBAL:
+ success:
+ /* Global definition. Just what we need. */
+ result->s = sym;
+ result->m = (struct link_map *) map;
+ return 1;
+
+ case STB_GNU_UNIQUE:;
+ /* We have to determine whether we already found a
+ symbol with this name before. If not then we have to
+ add it to the search table. If we already found a
+ definition we have to use it. */
+ void enter (struct unique_sym *table, size_t size,
+ unsigned int hash, const char *name,
+ const ElfW(Sym) *sym, const struct link_map *map)
+ {
+ size_t idx = hash % size;
+ size_t hash2 = 1 + hash % (size - 2);
+ while (1)
+ {
+ if (table[idx].hashval == 0)
+ {
+ table[idx].hashval = hash;
+ table[idx].name = strtab + sym->st_name;
+ if ((type_class & ELF_RTYPE_CLASS_COPY) != 0)
+ {
+ table[idx].sym = ref;
+ table[idx].map = undef_map;
+ }
+ else
+ {
+ table[idx].sym = sym;
+ table[idx].map = map;
+ }
+ return;
+ }
+
+ idx += hash2;
+ if (idx >= size)
+ idx -= size;
+ }
+ }
+
+ struct unique_sym_table *tab
+ = &GL(dl_ns)[map->l_ns]._ns_unique_sym_table;
+
+ __rtld_lock_lock_recursive (tab->lock);
+
+ struct unique_sym *entries = tab->entries;
+ size_t size = tab->size;
+ if (entries != NULL)
+ {
+ size_t idx = new_hash % size;
+ size_t hash2 = 1 + new_hash % (size - 2);
+ while (1)
+ {
+ if (entries[idx].hashval == new_hash
+ && strcmp (entries[idx].name, undef_name) == 0)
+ {
+ result->s = entries[idx].sym;
+ result->m = (struct link_map *) entries[idx].map;
+ __rtld_lock_unlock_recursive (tab->lock);
+ return 1;
+ }
+
+ if (entries[idx].hashval == 0
+ && entries[idx].name == NULL)
+ break;
+
+ idx += hash2;
+ if (idx >= size)
+ idx -= size;
+ }
+
+ if (size * 3 <= tab->n_elements)
+ {
+ /* Expand the table. */
+ size_t newsize = _dl_higher_prime_number (size);
+ struct unique_sym *newentries
+ = calloc (sizeof (struct unique_sym), newsize);
+ if (newentries == NULL)
+ {
+ nomem:
+ __rtld_lock_unlock_recursive (tab->lock);
+ _dl_fatal_printf ("out of memory\n");
+ }
+
+ for (idx = 0; idx < size; ++idx)
+ if (entries[idx].hashval != 0)
+ enter (newentries, newsize, entries[idx].hashval,
+ entries[idx].name, entries[idx].sym,
+ entries[idx].map);
+
+ tab->free (entries);
+ tab->size = newsize;
+ entries = tab->entries = newentries;
+ tab->free = free;
+ }
+ }
+ else
+ {
+#define INITIAL_NUNIQUE_SYM_TABLE 31
+ size = INITIAL_NUNIQUE_SYM_TABLE;
+ entries = calloc (sizeof (struct unique_sym), size);
+ if (entries == NULL)
+ goto nomem;
+
+ tab->entries = entries;
+ tab->size = size;
+ tab->free = free;
+ }
+
+ enter (entries, size, new_hash, strtab + sym->st_name, sym, map);
+ ++tab->n_elements;
+
+ __rtld_lock_unlock_recursive (tab->lock);
+
+ goto success;
+
+ default:
+ /* Local symbols are ignored. */
+ break;
+ }
+ }
+
+ /* 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 != NULL && version->filename != NULL
+ && __builtin_expect (_dl_name_match_p (version->filename, map), 0))
+ return -1;
+ }
+ while (++i < n);
+
+ /* We have not found anything until now. */
+ return 0;
+}
static uint_fast32_t
{
int res = do_lookup_x (undef_name, new_hash, &old_hash, *ref,
¤t_value, *scope, start, version, flags,
- skip_map, type_class);
+ skip_map, type_class, undef_map);
if (res > 0)
break;
for (scope = symbol_scope; *scope != NULL; i = 0, ++scope)
if (do_lookup_x (undef_name, new_hash, &old_hash, *ref,
&protected_value, *scope, i, version, flags,
- skip_map, ELF_RTYPE_CLASS_PLT) != 0)
+ skip_map, ELF_RTYPE_CLASS_PLT, NULL) != 0)
break;
if (protected_value.s != NULL && protected_value.m != undef_map)
do_lookup_x (undef_name, new_hash, &old_hash, *ref, &val,
undef_map->l_local_scope[0], 0, version, 0, NULL,
- type_class);
+ type_class, undef_map);
if (val.s != value->s || val.m != value->m)
conflict = 1;
}
- if (value->s
- && (__builtin_expect (ELFW(ST_TYPE) (value->s->st_info)
- == STT_TLS, 0)))
- type_class = 4;
+ if (value->s)
+ {
+ if (__builtin_expect (ELFW(ST_TYPE) (value->s->st_info)
+ == STT_TLS, 0))
+ type_class = 4;
+ else if (__builtin_expect (ELFW(ST_TYPE) (value->s->st_info)
+ == STT_GNU_IFUNC, 0))
+ type_class |= 8;
+ }
if (conflict
|| GLRO(dl_trace_prelink_map) == undef_map
|| GLRO(dl_trace_prelink_map) == NULL
- || type_class == 4)
+ || type_class >= 4)
{
_dl_printf ("%s 0x%0*Zx 0x%0*Zx -> 0x%0*Zx 0x%0*Zx ",
conflict ? "conflict" : "lookup",
projects / platform / upstream / linaro-glibc.git / commitdiff