1 files changed, 368 insertions, 5 deletions

diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index 707d650719..fd0d624430 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -69,8 +69,371 @@ struct sym_val
 #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);
+	if (__builtin_expect ((sym->st_value == 0 /* No value.  */
+			       && stt != STT_TLS)
+			      || (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
@@ -337,7 +700,7 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
     {
       int res = do_lookup_x (undef_name, new_hash, &old_hash, *ref,
 			     &current_value, *scope, start, version, flags,
-			     skip_map, type_class);
+			     skip_map, type_class, undef_map);
       if (res > 0)
 	break;
 
@@ -410,7 +773,7 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
 	  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)
@@ -536,7 +899,7 @@ _dl_debug_bindings (const char *undef_name, struct link_map *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;