A patch for the unversioned lookup

A patch for the unversioned lookup

[H . J . Lu]

[-- Attachment #1: Type: text/plain, Size: 1143 bytes --]

While working on the atexit related problem, I noticed 2 problems
with the unversioned lookup:

1. The version index starts at 2 not 3. That is we should check
ndx > 1, not ndx > 2, for version names.
2. We should allow the hidden definition if there is no default
definition as long as there is only one definition.

I am also enclosing a testcase here.


H.J.
----
2001-05-03  H.J. Lu  <hjl@gnu.org>

	* do-lookup.h (FCT): Fix the unversioned lookup against the
	nono-default version definition.

--- libc/elf/do-lookup.h.nodef	Tue Feb 27 22:22:10 2001
+++ libc/elf/do-lookup.h	Thu May  3 14:49:24 2001
@@ -125,11 +125,10 @@ FCT (const char *undef_name, unsigned lo
 	  if (verstab != NULL)
 	    {
 	      ElfW(Half) ndx = verstab[symidx] & 0x7fff;
-	      if (ndx > 2) /* map->l_versions[ndx].hash != 0) */
+	      if (ndx > 1) /* map->l_versions[ndx].hash != 0) */
 		{
-		  /* Don't accept hidden symbols.  */
-		  if ((verstab[symidx] & 0x8000) == 0 && num_versions++ == 0)
-		    /* No version so far.  */
+		  if (num_versions++ == 0)
+		    /* Only one version so far.  */
 		    versioned_sym = sym;
 		  continue;
 		}
Reply-To: 


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Re: A patch for the unversioned lookup

[Ulrich Drepper]

"H . J . Lu" <hjl@lucon.org> writes:

> While working on the atexit related problem, I noticed 2 problems
> with the unversioned lookup:

I will not even look at this unless you provide examples.

-- 
---------------.                          ,-.   1325 Chesapeake Terrace
Ulrich Drepper  \    ,-------------------'   \  Sunnyvale, CA 94089 USA
Red Hat          `--' drepper at redhat.com   `------------------------

Re: A patch for the unversioned lookup

[H . J . Lu]

On Thu, May 03, 2001 at 08:27:46PM -0700, Ulrich Drepper wrote:
> "H . J . Lu" <hjl@lucon.org> writes:
> 
> > While working on the atexit related problem, I noticed 2 problems
> > with the unversioned lookup:
> 
> I will not even look at this unless you provide examples.
> 

I enclosed a testcase in

http://sources.redhat.com/ml/libc-alpha/2001-05/msg00021.html

The current glibc does

# make
cc    -c -o foo.o foo.c
cc -fPIC -c b.c
cc -shared -o lib-b.so b.o
cc -fPIC -c c0.c
cc -Wl,-soname,lib-c.so -shared -o lib-c0.so c0.o
cp lib-c0.so lib-c.so
cc -o foo -Wl,-rpath,. foo.o lib-b.so lib-c.so
cc -fPIC -c c1.c
cc -Wl,-soname,lib-c.so -Wl,--version-script=c.map -shared -o lib-c1.so c1.o
cc -fPIC -c c2.c
cc -Wl,-soname,lib-c.so -Wl,--version-script=c.map -shared -o lib-c2.so c2.o
./foo
bar
cp lib-c1.so lib-c.so
./foo
bar
cp lib-c2.so lib-c.so
./foo
bar

The last one should fail since

# objdump --dynamic-sym lib-c.so | grep bar
000000000000086c g    DF .text  000000000000002a  Base        _old_bar_1
0000000000000840 g    DF .text  000000000000002a  Base        _old_bar
000000000000086c g    DF .text  000000000000002a (VERS.1)     bar
0000000000000840 g    DF .text  000000000000002a (VERS.0)     bar

There are 2 versions of bar, but none of them is default. With my
patch, I got

# /export/build/gnu/glibc/elf/ld-linux.so.2 ./foo
./foo: error while loading shared libraries: ./lib-b.so: undefined symbol: bar

Let me know if you have trouble getting my testcase.

Thanks.



H.J.

Re: A patch for the unversioned lookup

[H . J . Lu]

On Thu, May 03, 2001 at 08:39:40PM -0700, H . J . Lu wrote:
> On Thu, May 03, 2001 at 08:27:46PM -0700, Ulrich Drepper wrote:
> > "H . J . Lu" <hjl@lucon.org> writes:
> > 
> > > While working on the atexit related problem, I noticed 2 problems
> > > with the unversioned lookup:
> > 
> > I will not even look at this unless you provide examples.
> > 
> 
> I enclosed a testcase in
> 
> http://sources.redhat.com/ml/libc-alpha/2001-05/msg00021.html
> 
> The current glibc does
> 
> # make
> cc    -c -o foo.o foo.c
> cc -fPIC -c b.c
> cc -shared -o lib-b.so b.o
> cc -fPIC -c c0.c
> cc -Wl,-soname,lib-c.so -shared -o lib-c0.so c0.o
> cp lib-c0.so lib-c.so
> cc -o foo -Wl,-rpath,. foo.o lib-b.so lib-c.so
> cc -fPIC -c c1.c
> cc -Wl,-soname,lib-c.so -Wl,--version-script=c.map -shared -o lib-c1.so c1.o
> cc -fPIC -c c2.c
> cc -Wl,-soname,lib-c.so -Wl,--version-script=c.map -shared -o lib-c2.so c2.o
> ./foo
> bar
> cp lib-c1.so lib-c.so
> ./foo
> bar
> cp lib-c2.so lib-c.so
> ./foo
> bar
> 
> The last one should fail since
> 
> # objdump --dynamic-sym lib-c.so | grep bar
> 000000000000086c g    DF .text  000000000000002a  Base        _old_bar_1
> 0000000000000840 g    DF .text  000000000000002a  Base        _old_bar
> 000000000000086c g    DF .text  000000000000002a (VERS.1)     bar
> 0000000000000840 g    DF .text  000000000000002a (VERS.0)     bar
> 
> There are 2 versions of bar, but none of them is default. With my
> patch, I got
> 
> # /export/build/gnu/glibc/elf/ld-linux.so.2 ./foo
> ./foo: error while loading shared libraries: ./lib-b.so: undefined symbol: bar
> 
> Let me know if you have trouble getting my testcase.
> 
> Thanks.
> 
> 

That is incorrect. Here is a new one. I will send a patch for a new
testcase in glibc.


H.J.
----
2001-05-03  H.J. Lu  <hjl@gnu.org>

	* do-lookup.h (FCT): Fix the unversioned lookup against the
	nono-default version definition.

--- libc/elf/do-lookup.h.nodef	Tue Feb 27 22:22:10 2001
+++ libc/elf/do-lookup.h	Thu May  3 23:06:37 2001
@@ -125,13 +125,21 @@ FCT (const char *undef_name, unsigned lo
 	  if (verstab != NULL)
 	    {
 	      ElfW(Half) ndx = verstab[symidx] & 0x7fff;
-	      if (ndx > 2) /* map->l_versions[ndx].hash != 0) */
+	      if (ndx > 1) /* map->l_versions[ndx].hash != 0) */
 		{
-		  /* Don't accept hidden symbols.  */
-		  if ((verstab[symidx] & 0x8000) == 0 && num_versions++ == 0)
-		    /* No version so far.  */
-		    versioned_sym = sym;
-		  continue;
+		  if ((verstab[symidx] & 0x8000) == 0)
+		    {
+		      /* We found the default version.  */
+		      goto found_it;
+		    }
+		  else
+		    {
+		      /* We found a hidden symbol. Only one version is
+			 allowed.  */
+		      if (num_versions++ == 0)
+			versioned_sym = sym;
+		      continue;
+		    }
 		}
 	    }
 #endif

Re: A patch for the unversioned lookup

[H . J . Lu]

On Thu, May 03, 2001 at 11:14:02PM -0700, H . J . Lu wrote:
> 
> That is incorrect. Here is a new one. I will send a patch for a new
> testcase in glibc.
> 

Here is the testcase for glibc.


H.J.
---
2001-05-04  H.J. Lu  <hjl@gnu.org>

	* elf/Makefile (distribute): Add tst-version.sh, version.map,
	versionobj0.c, versionobj1.c and versionobj2.c.
	(test-srcs): Add tst-version.
	(modules-names): Add versionobj1 and versionobj2.
	(tests): Also depend on $(objpfx)tst-version.out.
	$(objpfx)%.so: Also filter out versionobj1 and versionobj2.
	($(objpfx)versionobj0a.so): New target.
	($(objpfx)versionobj0b.so): New target.
	($(objpfx)versionobj1.so): New target.
	($(objpfx)versionobj2.so): New target.
	($(objpfx)versionobj.so): New target.
	($(objpfx)tst-version): New target.
	($(objpfx)tst-version.out): New target.

	* elf/tst-version.c: New file.
	* elf/tst-version.sh: New file.
	* elf/version.map: New file.
	* elf/versionobj0.c: New file.
	* elf/versionobj1.c: New file.
	* elf/versionobj2.c: New file.

--- libc/elf/Makefile.version	Sat Mar 24 21:04:33 2001
+++ libc/elf/Makefile	Fri May  4 00:23:43 2001
@@ -57,7 +57,9 @@ distribute	:= $(rtld-routines:=.c) dynam
 		   neededobj1.c neededobj2.c neededobj3.c neededobj4.c \
 		   neededobj5.c neededobj6.c firstobj.c \
 		   unload2mod.c unload2dep.c ltglobmod1.c ltglobmod2.c \
-		   testobj.h vismod.h globalmod1.c
+		   testobj.h vismod.h globalmod1.c \
+		   tst-version.sh version.map versionobj0.c \
+		   versionobj1.c versionobj2.c
 
 include ../Makeconfig
 
@@ -102,7 +104,7 @@ tests = loadtest restest1 preloadtest lo
 	reldep reldep2 reldep3 next $(tests-nodelete-$(have-z-nodelete)) \
 	$(tests-nodlopen-$(have-z-nodlopen)) neededtest neededtest2 \
 	neededtest3 neededtest4 unload2 lateglobal initfirst global
-test-srcs = tst-pathopt
+test-srcs = tst-pathopt tst-version
 tests-vis-yes = vismain
 tests-nodelete-yes = nodelete
 tests-nodlopen-yes = nodlopen
@@ -115,7 +117,8 @@ modules-names = testobj1 testobj2 testob
 		reldepmod1 reldepmod2 reldepmod3 reldepmod4 nextmod1 nextmod2 \
 		neededobj1 neededobj2 neededobj3 neededobj4 \
 		neededobj5 neededobj6 firstobj globalmod1 \
-		unload2mod unload2dep ltglobmod1 ltglobmod2 pathoptobj
+		unload2mod unload2dep ltglobmod1 ltglobmod2 pathoptobj \
+		versionobj1 versionobj2
 modules-vis-yes = vismod1 vismod2 vismod3
 modules-nodelete-yes = nodelmod1 nodelmod2 nodelmod3 nodelmod4
 modules-nodlopen-yes = nodlopenmod
@@ -247,7 +250,7 @@ generated += $(addsuffix .so,$(strip $(m
 
 ifeq (yes,$(build-shared))
 ifeq ($(cross-compiling),no)
-tests: $(objpfx)tst-pathopt.out
+tests: $(objpfx)tst-pathopt.out $(objpfx)tst-version.out
 endif
 endif
 
@@ -276,7 +279,10 @@ $(objpfx)firstobj.so: $(shared-thread-li
 $(objpfx)globalmod1.so: $(libdl)
 
 # filtmod1.so has a special rule
-$(filter-out $(objpfx)filtmod1.so, $(test-modules)): $(objpfx)%.so: $(objpfx)%.os
+$(filter-out $(objpfx)filtmod1.so \
+	     $(objpfx)versionobj1.so \
+	     $(objpfx)versionobj2.so, \
+	     $(test-modules)): $(objpfx)%.so: $(objpfx)%.os
 	$(build-module)
 
 $(objpfx)loadtest: $(libdl)
@@ -369,6 +375,41 @@ $(objpfx)filtmod1.so: $(objpfx)filtmod1.
 		  -Wl,-rpath-link=$(rpath-link) \
 		  $< -Wl,-F,$(objpfx)filtmod2.so
 $(objpfx)filter: $(objpfx)filtmod1.so
+
+$(objpfx)versionobj0a.so: $(objpfx)versionobj0.os
+	$(LINK.o) -shared -o $@ -B$(csu-objpfx) $(LDFLAGS.so) \
+		  -L$(subst :, -L,$(rpath-link)) \
+		  -Wl,-rpath-link=$(rpath-link) $<
+
+$(objpfx)versionobj0b.so: $(objpfx)versionobj0.os
+	$(LINK.o) -shared -o $@ -B$(csu-objpfx) $(LDFLAGS.so) \
+		  -L$(subst :, -L,$(rpath-link)) \
+		  -Wl,-rpath-link=$(rpath-link) $< \
+		  -Wl,--version-script=version.map
+
+$(objpfx)versionobj1.so: $(objpfx)versionobj1.os
+	$(LINK.o) -shared -o $@ -B$(csu-objpfx) $(LDFLAGS.so) \
+		  -L$(subst :, -L,$(rpath-link)) \
+		  -Wl,-rpath-link=$(rpath-link) $< \
+		  -Wl,--version-script=version.map
+
+$(objpfx)versionobj2.so: $(objpfx)versionobj2.os
+	$(LINK.o) -shared -o $@ -B$(csu-objpfx) $(LDFLAGS.so) \
+		  -L$(subst :, -L,$(rpath-link)) \
+		  -Wl,-rpath-link=$(rpath-link) $< \
+		  -Wl,--version-script=version.map
+
+$(objpfx)tst-version: $(objpfx)versionobj.so
+$(objpfx)versionobj.so: $(objpfx)versionobj0a.so
+	rm -f $@
+	ln -s $(<F) $@
+
+$(objpfx)tst-version.out: tst-version.sh $(objpfx)tst-version \
+			  $(objpfx)versionobj0a.so \
+			  $(objpfx)versionobj0b.so \
+			  $(objpfx)versionobj1.so \
+			  $(objpfx)versionobj2.so
+	$(SHELL) $< $(common-objpfx) > $@
 
 $(objpfx)unload: $(libdl)
 $(objpfx)unload.out: $(objpfx)unloadmod.so
--- libc/elf/tst-version.c.version	Thu May  3 23:40:15 2001
+++ libc/elf/tst-version.c	Thu May  3 23:36:48 2001
@@ -0,0 +1,20 @@
+#include <stdlib.h>
+
+extern int bar (void);
+extern int foo;
+
+int
+main(int argc, char **argv)
+{
+  int result = 0;
+
+  if (argc > 1)
+    result = atoi (argv [1]);
+  
+  if (bar () != result || foo != result)
+    result = 1;
+  else
+    result = 0;
+
+  return result;
+}
--- libc/elf/tst-version.sh.version	Thu May  3 23:27:01 2001
+++ libc/elf/tst-version.sh	Fri May  4 00:27:06 2001
@@ -0,0 +1,52 @@
+#! /bin/sh
+# Test versioned symbol lookup.
+# Copyright (C) 2001 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
+# modify it under the terms of the GNU Library General Public License as
+# published by the Free Software Foundation; either version 2 of the
+# License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Library General Public License for more details.
+#
+# You should have received a copy of the GNU Library General Public
+# License along with the GNU C Library; see the file COPYING.LIB.  If
+# not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+common_objpfx=$1
+
+rm -f ${common_objpfx}elf/versionobj.so
+ln -s versionobj0a.so ${common_objpfx}elf/versionobj.so
+LOCPATH=${common_objpfx}localedata GCONV_PATH=${common_objpfx}iconvdata \
+LC_ALL=C LD_LIBRARY_PATH=${common_objpfx}. \
+  ${common_objpfx}elf/ld.so ${common_objpfx}elf/tst-version 0
+test $? = 0 || exit 1
+
+rm -f ${common_objpfx}elf/versionobj.so
+ln -s versionobj0b.so ${common_objpfx}elf/versionobj.so
+LOCPATH=${common_objpfx}localedata GCONV_PATH=${common_objpfx}iconvdata \
+LC_ALL=C LD_LIBRARY_PATH=${common_objpfx}. \
+  ${common_objpfx}elf/ld.so ${common_objpfx}elf/tst-version 0
+test $? = 0 || exit 1
+
+rm -f ${common_objpfx}elf/versionobj.so
+ln -s versionobj1.so ${common_objpfx}elf/versionobj.so
+LOCPATH=${common_objpfx}localedata GCONV_PATH=${common_objpfx}iconvdata \
+LC_ALL=C LD_LIBRARY_PATH=${common_objpfx}. \
+  ${common_objpfx}elf/ld.so ${common_objpfx}elf/tst-version 1
+test $? = 0 || exit 1
+
+rm -f ${common_objpfx}elf/versionobj.so
+ln -s versionobj2.so ${common_objpfx}elf/versionobj.so
+LOCPATH=${common_objpfx}localedata GCONV_PATH=${common_objpfx}iconvdata \
+LC_ALL=C LD_LIBRARY_PATH=${common_objpfx}. \
+  ${common_objpfx}elf/ld.so ${common_objpfx}elf/tst-version 2
+test $? = 0 && rm -f ${common_objpfx}elf/versionobj.so && exit 1
+rm -f ${common_objpfx}elf/versionobj.so
+
+exit 0
--- libc/elf/version.map.version	Thu May  3 23:40:02 2001
+++ libc/elf/version.map	Thu May  3 23:40:33 2001
@@ -0,0 +1,11 @@
+VERS.0 {
+  global:
+    bar;
+    foo;
+};
+
+VERS.1 {
+  global:
+    bar;
+    foo;
+} VERS.0;
--- libc/elf/versionobj0.c.version	Thu May  3 23:42:15 2001
+++ libc/elf/versionobj0.c	Thu May  3 23:41:44 2001
@@ -0,0 +1,7 @@
+int foo = 0;
+
+int
+bar (void) 
+{
+  return foo;
+}
--- libc/elf/versionobj1.c.version	Thu May  3 23:42:18 2001
+++ libc/elf/versionobj1.c	Thu May  3 23:41:57 2001
@@ -0,0 +1,10 @@
+__asm__(".symver _old_bar,bar@VERS.0");
+__asm__(".symver _old_foo,foo@VERS.0");
+
+int _old_foo = 1;
+
+int
+_old_bar (void) 
+{
+  return _old_foo;
+}
--- libc/elf/versionobj2.c.version	Thu May  3 23:42:31 2001
+++ libc/elf/versionobj2.c	Thu May  3 23:42:05 2001
@@ -0,0 +1,20 @@
+__asm__(".symver _old_bar,bar@VERS.0");
+__asm__(".symver _old_foo,foo@VERS.0");
+
+int _old_foo = 2;
+
+int
+_old_bar (void) 
+{
+  return _old_foo;
+}
+
+__asm__(".symver _old_bar_1,bar@VERS.1");
+__asm__(".symver _old_foo_1,foo@VERS.1");
+
+int _old_foo_1 = 2;
+int
+_old_bar_1 (void) 
+{
+  return _old_foo_1;
+}

Re: A patch for the unversioned lookup

[H . J . Lu]

On Thu, May 03, 2001 at 11:14:02PM -0700, H . J . Lu wrote:
> > 
> 
> That is incorrect. Here is a new one. I will send a patch for a new
> testcase in glibc.
> 
> 

Here is an update. I modified do_lookup to return version name and
print it out if asked. It is useful to know which vesion of an
unversioned symbol is bound to.

H.J.
----
2001-05-04  H.J. Lu  <hjl@gnu.org>

	* elf/dl-lookup.c (_dl_lookup_symbol): Get version name from
	do_lookup and print it out if asked.
	(_dl_lookup_symbol_skip): Likewise.

	* do-lookup.h (do_lookup): Return version name. Fix the
	unversioned lookup against the nono-default version definition.

--- libc/elf/dl-lookup.c.nodef	Tue Feb 27 22:22:10 2001
+++ libc/elf/dl-lookup.c	Fri May  4 09:10:30 2001
@@ -197,13 +197,14 @@ _dl_lookup_symbol (const char *undef_nam
   int protected;
   int noexec = elf_machine_lookup_noexec_p (reloc_type);
   int noplt = elf_machine_lookup_noplt_p (reloc_type);
+  const char *version_name = NULL;
 
   ++_dl_num_relocations;
 
   /* Search the relevant loaded objects for a definition.  */
   for (scope = symbol_scope; *scope; ++scope)
-    if (do_lookup (undef_name, hash, *ref, &current_value, *scope, 0, NULL,
-		   noexec, noplt))
+    if (do_lookup (undef_name, hash, *ref, &current_value, *scope, 0,
+		   &version_name, NULL, noexec, noplt))
       {
 	/* We have to check whether this would bind UNDEF_MAP to an object
 	   in the global scope which was dynamically loaded.  In this case
@@ -242,12 +243,13 @@ _dl_lookup_symbol (const char *undef_nam
   protected = *ref && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED;
 
   if (__builtin_expect (_dl_debug_mask & DL_DEBUG_BINDINGS, 0))
-    _dl_debug_printf ("binding file %s to %s: %s symbol `%s'\n",
+    _dl_debug_printf ("binding file %s to %s: %s symbol `%s' [%s]\n",
 		      (reference_name && reference_name[0]
 		       ? reference_name : (_dl_argv[0] ?: "<main program>")),
 		       current_value.m->l_name[0]
 		       ? current_value.m->l_name : _dl_argv[0],
-		       protected ? "protected" : "normal", undef_name);
+		       protected ? "protected" : "normal", undef_name,
+		       version_name ?: "Base");
 
   if (__builtin_expect (protected == 0, 1))
     {
@@ -262,7 +264,7 @@ _dl_lookup_symbol (const char *undef_nam
 
       for (scope = symbol_scope; *scope; ++scope)
 	if (do_lookup (undef_name, hash, *ref, &protected_value, *scope, 0,
-		       NULL, 0, 1))
+		       &version_name, NULL, 0, 1))
 	  break;
 
       if (protected_value.s == NULL || protected_value.m == undef_map)
@@ -294,6 +296,7 @@ _dl_lookup_symbol_skip (const char *unde
   struct r_scope_elem **scope;
   size_t i;
   int protected;
+  const char *version_name = NULL;
 
   ++_dl_num_relocations;
 
@@ -304,10 +307,10 @@ _dl_lookup_symbol_skip (const char *unde
 
   if (i >= (*scope)->r_nlist
 	 || ! do_lookup (undef_name, hash, *ref, &current_value, *scope, i,
-			 skip_map, 0, 0))
+			 &version_name, skip_map, 0, 0))
     while (*++scope)
       if (do_lookup (undef_name, hash, *ref, &current_value, *scope, 0,
-		     skip_map, 0, 0))
+		     &version_name, skip_map, 0, 0))
 	break;
 
   if (__builtin_expect (current_value.s == NULL, 0))
@@ -319,12 +322,13 @@ _dl_lookup_symbol_skip (const char *unde
   protected = *ref && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED;
 
   if (__builtin_expect (_dl_debug_mask & DL_DEBUG_BINDINGS, 0))
-    _dl_debug_printf ("binding file %s to %s: %s symbol `%s'\n",
+    _dl_debug_printf ("binding file %s to %s: %s symbol `%s' [%s]\n",
 		       (reference_name && reference_name[0]
 			? reference_name : (_dl_argv[0] ?: "<main program>")),
 		       current_value.m->l_name[0]
 		       ? current_value.m->l_name : _dl_argv[0],
-		       protected ? "protected" : "normal", undef_name);
+		       protected ? "protected" : "normal", undef_name,
+		       version_name ?: "Base");
 
   if (__builtin_expect (protected == 0, 1))
     {
@@ -339,10 +343,10 @@ _dl_lookup_symbol_skip (const char *unde
 
       if (i >= (*scope)->r_nlist
 	  || !do_lookup (undef_name, hash, *ref, &protected_value, *scope, i,
-			 skip_map, 0, 1))
+			 &version_name, skip_map, 0, 1))
 	while (*++scope)
 	  if (do_lookup (undef_name, hash, *ref, &protected_value, *scope, 0,
-			 skip_map, 0, 1))
+			 &version_name, skip_map, 0, 1))
 	    break;
 
       if (protected_value.s == NULL || protected_value.m == undef_map)
--- libc/elf/do-lookup.h.nodef	Tue Feb 27 22:22:10 2001
+++ libc/elf/do-lookup.h	Fri May  4 09:05:52 2001
@@ -22,7 +22,7 @@
 # define ARG const struct r_found_version *const version,
 #else
 # define FCT do_lookup
-# define ARG
+# define ARG const char **version_name,
 #endif
 
 /* Inner part of the lookup functions.  We return a value > 0 if we
@@ -125,13 +125,25 @@ FCT (const char *undef_name, unsigned lo
 	  if (verstab != NULL)
 	    {
 	      ElfW(Half) ndx = verstab[symidx] & 0x7fff;
-	      if (ndx > 2) /* map->l_versions[ndx].hash != 0) */
+	      if (ndx > 1) /* map->l_versions[ndx].hash != 0) */
 		{
-		  /* Don't accept hidden symbols.  */
-		  if ((verstab[symidx] & 0x8000) == 0 && num_versions++ == 0)
-		    /* No version so far.  */
-		    versioned_sym = sym;
-		  continue;
+		  if ((verstab[symidx] & 0x8000) == 0)
+		    {
+		      /* We found the default version.  */
+		      *version_name = map->l_versions[ndx].name;
+		      goto found_it;
+		    }
+		  else
+		    {
+		      /* We found a hidden symbol. Only one version is
+			 allowed.  */
+		      if (num_versions++ == 0)
+			{
+			  versioned_sym = sym;
+			  *version_name = map->l_versions[ndx].name;
+			}
+		      continue;
+		    }
 		}
 	    }
 #endif

Re: A patch for the unversioned lookup

[H . J . Lu]

On Fri, May 04, 2001 at 09:18:23AM -0700, H . J . Lu wrote:
> On Thu, May 03, 2001 at 11:14:02PM -0700, H . J . Lu wrote:
> > > 
> > 
> > That is incorrect. Here is a new one. I will send a patch for a new
> > testcase in glibc.
> > 
> > 
> 
> Here is an update. I modified do_lookup to return version name and
> print it out if asked. It is useful to know which vesion of an
> unversioned symbol is bound to.
> 
> H.J.
> ----
> 2001-05-04  H.J. Lu  <hjl@gnu.org>
> 
> 	* elf/dl-lookup.c (_dl_lookup_symbol): Get version name from
> 	do_lookup and print it out if asked.
> 	(_dl_lookup_symbol_skip): Likewise.
> 
> 	* do-lookup.h (do_lookup): Return version name. Fix the
> 	unversioned lookup against the nono-default version definition.
> 

This patch is wrong. I will fix it.


H.J.

Re: A patch for the unversioned lookup

[H . J . Lu]

On Wed, May 09, 2001 at 04:04:03PM -0700, H . J . Lu wrote:
> On Fri, May 04, 2001 at 09:18:23AM -0700, H . J . Lu wrote:
> > On Thu, May 03, 2001 at 11:14:02PM -0700, H . J . Lu wrote:
> > > > 
> > > 
> > > That is incorrect. Here is a new one. I will send a patch for a new
> > > testcase in glibc.
> > > 
> > > 
> > 
> > Here is an update. I modified do_lookup to return version name and
> > print it out if asked. It is useful to know which vesion of an
> > unversioned symbol is bound to.
> > 
> > H.J.
> > ----
> > 2001-05-04  H.J. Lu  <hjl@gnu.org>
> > 
> > 	* elf/dl-lookup.c (_dl_lookup_symbol): Get version name from
> > 	do_lookup and print it out if asked.
> > 	(_dl_lookup_symbol_skip): Likewise.
> > 
> > 	* do-lookup.h (do_lookup): Return version name. Fix the
> > 	unversioned lookup against the nono-default version definition.
> > 
> 
> This patch is wrong. I will fix it.
> 
> 

The current glibc is ok. I was wrong. This patch doesn't fix any bug.
But it may help debug code.


H.J.
----
2001-05-03  H.J. Lu  <hjl@gnu.org>

	* elf/dl-lookup.c (_dl_lookup_symbol): Get version name from
	do_lookup and print it out if asked.
	(_dl_lookup_symbol_skip): Likewise.

	* do-lookup.h (do_lookup): Return version name.

--- libc/elf/dl-lookup.c.version	Wed May  9 16:22:07 2001
+++ libc/elf/dl-lookup.c	Wed May  9 16:23:03 2001
@@ -197,13 +197,14 @@ _dl_lookup_symbol (const char *undef_nam
   int protected;
   int noexec = elf_machine_lookup_noexec_p (reloc_type);
   int noplt = elf_machine_lookup_noplt_p (reloc_type);
+  const char *version_name = NULL;
 
   ++_dl_num_relocations;
 
   /* Search the relevant loaded objects for a definition.  */
   for (scope = symbol_scope; *scope; ++scope)
-    if (do_lookup (undef_name, hash, *ref, &current_value, *scope, 0, NULL,
-		   noexec, noplt))
+    if (do_lookup (undef_name, hash, *ref, &current_value, *scope, 0,
+		   &version_name, NULL, noexec, noplt))
       {
 	/* We have to check whether this would bind UNDEF_MAP to an object
 	   in the global scope which was dynamically loaded.  In this case
@@ -242,12 +243,13 @@ _dl_lookup_symbol (const char *undef_nam
   protected = *ref && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED;
 
   if (__builtin_expect (_dl_debug_mask & DL_DEBUG_BINDINGS, 0))
-    _dl_debug_printf ("binding file %s to %s: %s symbol `%s'\n",
+    _dl_debug_printf ("binding file %s to %s: %s symbol `%s' [%s]\n",
 		      (reference_name && reference_name[0]
 		       ? reference_name : (_dl_argv[0] ?: "<main program>")),
 		       current_value.m->l_name[0]
 		       ? current_value.m->l_name : _dl_argv[0],
-		       protected ? "protected" : "normal", undef_name);
+		       protected ? "protected" : "normal", undef_name,
+		       version_name ?: "Base");
 
   if (__builtin_expect (protected == 0, 1))
     {
@@ -262,7 +264,7 @@ _dl_lookup_symbol (const char *undef_nam
 
       for (scope = symbol_scope; *scope; ++scope)
 	if (do_lookup (undef_name, hash, *ref, &protected_value, *scope, 0,
-		       NULL, 0, 1))
+		       &version_name, NULL, 0, 1))
 	  break;
 
       if (protected_value.s == NULL || protected_value.m == undef_map)
@@ -294,6 +296,7 @@ _dl_lookup_symbol_skip (const char *unde
   struct r_scope_elem **scope;
   size_t i;
   int protected;
+  const char *version_name = NULL;
 
   ++_dl_num_relocations;
 
@@ -304,10 +307,10 @@ _dl_lookup_symbol_skip (const char *unde
 
   if (i >= (*scope)->r_nlist
 	 || ! do_lookup (undef_name, hash, *ref, &current_value, *scope, i,
-			 skip_map, 0, 0))
+			 &version_name, skip_map, 0, 0))
     while (*++scope)
       if (do_lookup (undef_name, hash, *ref, &current_value, *scope, 0,
-		     skip_map, 0, 0))
+		     &version_name, skip_map, 0, 0))
 	break;
 
   if (__builtin_expect (current_value.s == NULL, 0))
@@ -319,12 +322,13 @@ _dl_lookup_symbol_skip (const char *unde
   protected = *ref && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED;
 
   if (__builtin_expect (_dl_debug_mask & DL_DEBUG_BINDINGS, 0))
-    _dl_debug_printf ("binding file %s to %s: %s symbol `%s'\n",
+    _dl_debug_printf ("binding file %s to %s: %s symbol `%s' [%s]\n",
 		       (reference_name && reference_name[0]
 			? reference_name : (_dl_argv[0] ?: "<main program>")),
 		       current_value.m->l_name[0]
 		       ? current_value.m->l_name : _dl_argv[0],
-		       protected ? "protected" : "normal", undef_name);
+		       protected ? "protected" : "normal", undef_name,
+		       version_name ?: "Base");
 
   if (__builtin_expect (protected == 0, 1))
     {
@@ -339,10 +343,10 @@ _dl_lookup_symbol_skip (const char *unde
 
       if (i >= (*scope)->r_nlist
 	  || !do_lookup (undef_name, hash, *ref, &protected_value, *scope, i,
-			 skip_map, 0, 1))
+			 &version_name, skip_map, 0, 1))
 	while (*++scope)
 	  if (do_lookup (undef_name, hash, *ref, &protected_value, *scope, 0,
-			 skip_map, 0, 1))
+			 &version_name, skip_map, 0, 1))
 	    break;
 
       if (protected_value.s == NULL || protected_value.m == undef_map)
--- libc/elf/do-lookup.h.version	Wed May  9 16:22:07 2001
+++ libc/elf/do-lookup.h	Wed May  9 16:37:45 2001
@@ -22,7 +22,7 @@
 # define ARG const struct r_found_version *const version,
 #else
 # define FCT do_lookup
-# define ARG
+# define ARG const char **version_name,
 #endif
 
 /* Inner part of the lookup functions.  We return a value > 0 if we
@@ -129,10 +129,14 @@ FCT (const char *undef_name, unsigned lo
 		{
 		  /* Don't accept hidden symbols.  */
 		  if ((verstab[symidx] & 0x8000) == 0 && num_versions++ == 0)
-		    /* No version so far.  */
-		    versioned_sym = sym;
+		    {
+		      /* No version so far.  */
+		      *version_name = map->l_versions[ndx].name;
+		      versioned_sym = sym;
+		    }
 		  continue;
 		}
+	      *version_name = map->l_versions[ndx].name;
 	    }
 #endif