Update.

	* elf/dl-lookup.c (do_lookup): If looking up an unversioned symbol
	but the object file only contains versioned definitions than
	accept the definition if there is exactly one even if the version
	number is not the default version.  This helps dlsym() to find
	newly introduced symbols.

1 files changed, 28 insertions, 9 deletions

diff --git a/elf/dl-lookup.c b/elf/dl-lookup.c
index 5245c628d2..8c99f499fd 100644
--- a/elf/dl-lookup.c
+++ b/elf/dl-lookup.c
@@ -77,6 +77,9 @@ do_lookup (const char *undef_name, unsigned long int hash,
       const char *strtab;
       const ElfW(Half) *verstab;
       ElfW(Symndx) symidx;
+      int num_versions = 0;
+      const ElfW(Sym) *sym;
+      const ElfW(Sym) *versioned_sym;
 
       map = list[i];
 
@@ -114,7 +117,7 @@ do_lookup (const char *undef_name, unsigned long int hash,
 	   symidx != STN_UNDEF;
 	   symidx = map->l_chain[symidx])
 	{
-	  const ElfW(Sym) *sym = &symtab[symidx];
+	  sym = &symtab[symidx];
 
 	  if (sym->st_value == 0 || /* No value.  */
 	      (elf_machine_lookup_noplt_p (reloc_type) /* Reject PLT entry.  */
@@ -134,13 +137,20 @@ do_lookup (const char *undef_name, unsigned long int hash,
 	    {
 	      /* No specific version is selected.  When the object
 		 file also does not define a version we have a match.
-		 Otherwise we only accept the default version, i.e.,
-		 the version which name is "".  */
+		 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) */
-		    continue;
+		    {
+		      /* Don't accept hidden symbols.  */
+		      if ((verstab[symidx] & 0x8000) == 0
+			  && num_versions++ == 0)
+			/* No version so far.  */
+			versioned_sym = sym;
+		      continue;
+		    }
 		}
 	    }
 	  else
@@ -170,6 +180,19 @@ do_lookup (const char *undef_name, unsigned long int hash,
 		}
 	    }
 
+	  /* There cannot be another entry for this symbol so stop here.  */
+	  goto found_it;
+	}
+
+      /* If we have seem 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 (ELFW(ST_BIND) (sym->st_info))
 	    {
 	    case STB_GLOBAL:
@@ -178,8 +201,7 @@ do_lookup (const char *undef_name, unsigned long int hash,
 	      result->m = map;
 	      return 1;
 	    case STB_WEAK:
-	      /* Weak definition.  Use this value if we don't find
-		 another.  */
+	      /* Weak definition.  Use this value if we don't find another.  */
 	      if (! result->s)
 		{
 		  result->s = sym;
@@ -190,9 +212,6 @@ do_lookup (const char *undef_name, unsigned long int hash,
 	      /* Local symbols are ignored.  */
 	      break;
 	    }
-
-	  /* There cannot be another entry for this symbol so stop here.  */
-	  break;
 	}
 
       /* If this current map is the one mentioned in the verneed entry