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When a dlopened module references a weak symbol from another dlopened
module (loaded with RTLD_GLOBAL) no dependency was generated for this
fact, so the second module was unloaded even if the first one was still
around.
I have included patches for both mainline and 2.2 branch.
Andreas.
2002-02-17 Andreas Schwab <schwab@suse.de>
* elf/dl-lookup.c (_dl_lookup_symbol): Check whether to call
add_dependency even if only weak symbols symbols were found.
(_dl_lookup_versioned_symbol): Likewise.
* reldep7.c, reldep7mod1.c, reldep7mod2.c: New files.
* Makefile: Add rules to build and run reldep7.
Index: elf/Makefile
===================================================================
RCS file: /cvs/glibc/libc/elf/Makefile,v
retrieving revision 1.208.2.3
diff -u -a -r1.208.2.3 elf/Makefile
--- elf/Makefile 2002/01/08 21:38:17 1.208.2.3
+++ elf/Makefile 2002/02/16 23:18:13
@@ -64,7 +64,7 @@
testobj.h vismod.h globalmod1.c \
dblloadmod1.c dblloadmod2.c dblloadmod3.c \
reldep6mod4.c reldep6mod3.c reldep6mod2.c reldep6mod1.c \
- reldep6mod0.c \
+ reldep6mod0.c reldep7mod1.c reldep7mod2.c \
unwind-dw2.c unwind-dw2-fde.c unwind.h unwind-pe.h \
unwind-dw2-fde.h dwarf2.h
@@ -116,7 +116,7 @@
reldep reldep2 reldep3 reldep4 $(tests-nodelete-$(have-z-nodelete)) \
$(tests-nodlopen-$(have-z-nodlopen)) neededtest neededtest2 \
neededtest3 neededtest4 unload2 lateglobal initfirst global \
- restest2 next dblload dblunload reldep5 reldep6
+ restest2 next dblload dblunload reldep5 reldep6 reldep7
test-srcs = tst-pathopt
tests-vis-yes = vismain
tests-nodelete-yes = nodelete
@@ -133,7 +133,8 @@
neededobj5 neededobj6 firstobj globalmod1 \
unload2mod unload2dep ltglobmod1 ltglobmod2 pathoptobj \
dblloadmod1 dblloadmod2 dblloadmod3 reldepmod5 reldepmod6 \
- reldep6mod0 reldep6mod1 reldep6mod2 reldep6mod3 reldep6mod4
+ reldep6mod0 reldep6mod1 reldep6mod2 reldep6mod3 reldep6mod4 \
+ reldep7mod1 reldep7mod2
modules-vis-yes = vismod1 vismod2 vismod3
modules-nodelete-yes = nodelmod1 nodelmod2 nodelmod3 nodelmod4
modules-nodlopen-yes = nodlopenmod
@@ -446,3 +447,6 @@
$(objpfx)reldep6: $(libdl)
$(objpfx)reldep6.out: $(objpfx)reldep6mod3.so $(objpfx)reldep6mod4.so
+
+$(objpfx)reldep7: $(libdl)
+$(objpfx)reldep7.out: $(objpfx)reldep7mod1.so $(objpfx)reldep7mod2.so
Index: elf/dl-lookup.c
===================================================================
RCS file: /cvs/glibc/libc/elf/dl-lookup.c,v
retrieving revision 1.87
diff -u -a -r1.87 elf/dl-lookup.c
--- elf/dl-lookup.c 2001/09/08 17:11:36 1.87
+++ elf/dl-lookup.c 2002/02/16 23:18:13
@@ -1,5 +1,5 @@
/* Look up a symbol in the loaded objects.
- Copyright (C) 1995,96,97,98,99,2000,2001 Free Software Foundation, Inc.
+ Copyright (C) 1995,96,97,98,99,2000,2001, 2002 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
@@ -215,25 +215,8 @@
for (scope = symbol_scope; *scope; ++scope)
if (do_lookup (undef_name, hash, *ref, ¤t_value, *scope, 0, NULL,
type_class))
- {
- /* We have to check whether this would bind UNDEF_MAP to an object
- in the global scope which was dynamically loaded. In this case
- we have to prevent the latter from being unloaded unless the
- UNDEF_MAP object is also unloaded. */
- if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
- /* Don't do this for explicit lookups as opposed to implicit
- runtime lookups. */
- && ! explicit
- /* Add UNDEF_MAP to the dependencies. */
- && 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 (undef_name, undef_map, ref, symbol_scope,
- type_class, 0);
+ break;
- break;
- }
-
if (__builtin_expect (current_value.s == NULL, 0))
{
const char *reference_name = undef_map ? undef_map->l_name : NULL;
@@ -250,6 +233,21 @@
return 0;
}
+ /* We have to check whether this would bind UNDEF_MAP to an object in
+ the global scope which was dynamically loaded. In this case we have
+ to prevent the latter from being unloaded unless the UNDEF_MAP object
+ is also unloaded. */
+ if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
+ /* Don't do this for explicit lookups as opposed to implicit runtime
+ lookups. */
+ && ! explicit
+ /* Add UNDEF_MAP to the dependencies. */
+ && 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 (undef_name, undef_map, ref, symbol_scope,
+ type_class, 0);
+
protected = *ref && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED;
if (__builtin_expect (_dl_debug_mask & DL_DEBUG_BINDINGS, 0))
@@ -396,25 +394,7 @@
int res = do_lookup_versioned (undef_name, hash, *ref, ¤t_value,
*scope, 0, version, NULL, type_class);
if (res > 0)
- {
- /* We have to check whether this would bind UNDEF_MAP to an object
- in the global scope which was dynamically loaded. In this case
- we have to prevent the latter from being unloaded unless the
- UNDEF_MAP object is also unloaded. */
- if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
- /* Don't do this for explicit lookups as opposed to implicit
- runtime lookups. */
- && ! explicit
- /* Add UNDEF_MAP to the dependencies. */
- && 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_versioned_symbol (undef_name, undef_map, ref,
- symbol_scope, version,
- type_class, 0);
-
- break;
- }
+ break;
if (__builtin_expect (res, 0) < 0)
{
@@ -457,6 +437,22 @@
*ref = NULL;
return 0;
}
+
+ /* We have to check whether this would bind UNDEF_MAP to an object in
+ the global scope which was dynamically loaded. In this case we have
+ to prevent the latter from being unloaded unless the UNDEF_MAP object
+ is also unloaded. */
+ if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
+ /* Don't do this for explicit lookups as opposed to implicit runtime
+ lookups. */
+ && ! explicit
+ /* Add UNDEF_MAP to the dependencies. */
+ && 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_versioned_symbol (undef_name, undef_map, ref,
+ symbol_scope, version,
+ type_class, 0);
protected = *ref && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED;
Index: elf/reldep7.c
===================================================================
RCS file: elf/reldep7.c
diff -N elf/reldep7.c
--- /dev/null Tue May 5 13:32:27 1998
+++ elf/reldep7.c Sat Feb 16 15:18:13 2002
@@ -0,0 +1,58 @@
+#include <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+main (void)
+{
+ void *h1;
+ void *h2;
+ void *mod1_bar, *mod2_bar;
+
+ h1 = dlopen ("reldep7mod1.so", RTLD_GLOBAL | RTLD_LAZY);
+ if (h1 == NULL)
+ {
+ printf ("cannot open reldep7mod1.so: %s\n", dlerror ());
+ exit (1);
+ }
+
+ h2 = dlopen ("reldep7mod2.so", RTLD_GLOBAL | RTLD_LAZY);
+ if (h2 == NULL)
+ {
+ printf ("cannot open reldep7mod1.so: %s\n", dlerror ());
+ exit (1);
+ }
+
+ mod1_bar = dlsym (h1, "mod1_bar");
+ if (mod1_bar == NULL)
+ {
+ printf ("cannot get address of \"mod1_bar\": %s\n", dlerror ());
+ exit (1);
+ }
+
+ mod2_bar = dlsym (h2, "mod2_bar");
+ if (mod2_bar == NULL)
+ {
+ printf ("cannot get address of \"mod2_bar\": %s\n", dlerror ());
+ exit (1);
+ }
+
+ printf ("%d\n", ((int (*) (void)) mod1_bar) ());
+ printf ("%d\n", ((int (*) (void)) mod2_bar) ());
+
+ if (dlclose (h1) != 0)
+ {
+ printf ("closing h1 failed: %s\n", dlerror ());
+ exit (1);
+ }
+
+ printf ("%d\n", ((int (*) (void)) mod2_bar) ());
+
+ if (dlclose (h2) != 0)
+ {
+ printf ("closing h2 failed: %s\n", dlerror ());
+ exit (1);
+ }
+
+ return 0;
+}
Index: elf/reldep7mod1.c
===================================================================
RCS file: elf/reldep7mod1.c
diff -N elf/reldep7mod1.c
--- /dev/null Tue May 5 13:32:27 1998
+++ elf/reldep7mod1.c Sat Feb 16 15:18:13 2002
@@ -0,0 +1,12 @@
+int foo (void) __attribute__ ((weak));
+int
+foo (void)
+{
+ return 1;
+}
+
+int
+mod1_bar (void)
+{
+ return foo ();
+}
Index: elf/reldep7mod2.c
===================================================================
RCS file: elf/reldep7mod2.c
diff -N elf/reldep7mod2.c
--- /dev/null Tue May 5 13:32:27 1998
+++ elf/reldep7mod2.c Sat Feb 16 15:18:13 2002
@@ -0,0 +1,12 @@
+int foo (void) __attribute__ ((weak));
+int
+foo (void)
+{
+ return 2;
+}
+
+int
+mod2_bar (void)
+{
+ return foo ();
+}
-------------------------------------------------------------------------------
Index: elf/Makefile
===================================================================
RCS file: /cvs/glibc/libc/elf/Makefile,v
retrieving revision 1.223
diff -u -a -r1.223 elf/Makefile
--- elf/Makefile 2002/02/14 10:33:21 1.223
+++ elf/Makefile 2002/02/16 23:20:42
@@ -65,7 +65,7 @@
testobj.h vismod.h globalmod1.c \
dblloadmod1.c dblloadmod2.c dblloadmod3.c \
reldep6mod4.c reldep6mod3.c reldep6mod2.c reldep6mod1.c \
- reldep6mod0.c \
+ reldep6mod0.c reldep7mod1.c reldep7mod2.c \
unwind-dw2.c unwind-dw2-fde.c unwind.h unwind-pe.h \
unwind-dw2-fde.h dwarf2.h dl-procinfo.c tls.h dl-tls.h \
tls-macros.h
@@ -118,8 +118,9 @@
reldep reldep2 reldep3 reldep4 $(tests-nodelete-$(have-z-nodelete)) \
$(tests-nodlopen-$(have-z-nodlopen)) neededtest neededtest2 \
neededtest3 neededtest4 unload2 lateglobal initfirst global \
- restest2 next dblload dblunload reldep5 reldep6 tst-tls1 tst-tls2 \
- tst-tls3 tst-tls4 tst-tls5 tst-tls6 tst-tls7 tst-tls8
+ restest2 next dblload dblunload reldep5 reldep6 reldep7 \
+ tst-tls1 tst-tls2 tst-tls3 tst-tls4 tst-tls5 tst-tls6 tst-tls7 \
+ tst-tls8
test-srcs = tst-pathopt
tests-vis-yes = vismain
tests-nodelete-yes = nodelete
@@ -137,6 +138,7 @@
unload2mod unload2dep ltglobmod1 ltglobmod2 pathoptobj \
dblloadmod1 dblloadmod2 dblloadmod3 reldepmod5 reldepmod6 \
reldep6mod0 reldep6mod1 reldep6mod2 reldep6mod3 reldep6mod4 \
+ reldep7mod1 reldep7mod2 \
tst-tlsmod1 tst-tlsmod2 tst-tlsmod3 tst-tlsmod4
modules-vis-yes = vismod1 vismod2 vismod3
modules-nodelete-yes = nodelmod1 nodelmod2 nodelmod3 nodelmod4
@@ -441,6 +443,9 @@
$(objpfx)reldep6: $(libdl)
$(objpfx)reldep6.out: $(objpfx)reldep6mod3.so $(objpfx)reldep6mod4.so
+
+$(objpfx)reldep7: $(libdl)
+$(objpfx)reldep7.out: $(objpfx)reldep7mod1.so $(objpfx)reldep7mod2.so
$(objpfx)tst-tls3: $(objpfx)tst-tlsmod1.so
Index: elf/dl-lookup.c
===================================================================
RCS file: /cvs/glibc/libc/elf/dl-lookup.c,v
retrieving revision 1.97
diff -u -a -r1.97 elf/dl-lookup.c
--- elf/dl-lookup.c 2002/02/11 01:27:01 1.97
+++ elf/dl-lookup.c 2002/02/16 23:20:42
@@ -228,25 +228,8 @@
for (scope = symbol_scope; *scope; ++scope)
if (do_lookup (undef_name, hash, *ref, ¤t_value, *scope, 0, NULL,
type_class))
- {
- /* We have to check whether this would bind UNDEF_MAP to an object
- in the global scope which was dynamically loaded. In this case
- we have to prevent the latter from being unloaded unless the
- UNDEF_MAP object is also unloaded. */
- if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
- /* Don't do this for explicit lookups as opposed to implicit
- runtime lookups. */
- && ! explicit
- /* Add UNDEF_MAP to the dependencies. */
- && 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 INTUSE(_dl_lookup_symbol) (undef_name, undef_map, ref,
- symbol_scope, type_class, 0);
+ break;
- break;
- }
-
if (__builtin_expect (current_value.s == NULL, 0))
{
const char *reference_name = undef_map ? undef_map->l_name : NULL;
@@ -263,6 +246,21 @@
return 0;
}
+ /* We have to check whether this would bind UNDEF_MAP to an object in
+ the global scope which was dynamically loaded. In this case we have
+ to prevent the latter from being unloaded unless the UNDEF_MAP object
+ is also unloaded. */
+ if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
+ /* Don't do this for explicit lookups as opposed to implicit runtime
+ lookups. */
+ && ! explicit
+ /* Add UNDEF_MAP to the dependencies. */
+ && 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 INTUSE(_dl_lookup_symbol) (undef_name, undef_map, ref,
+ symbol_scope, type_class, 0);
+
protected = *ref && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED;
if (__builtin_expect (protected != 0, 0))
{
@@ -390,25 +388,7 @@
int res = do_lookup_versioned (undef_name, hash, *ref, ¤t_value,
*scope, 0, version, NULL, type_class);
if (res > 0)
- {
- /* We have to check whether this would bind UNDEF_MAP to an object
- in the global scope which was dynamically loaded. In this case
- we have to prevent the latter from being unloaded unless the
- UNDEF_MAP object is also unloaded. */
- if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
- /* Don't do this for explicit lookups as opposed to implicit
- runtime lookups. */
- && ! explicit
- /* Add UNDEF_MAP to the dependencies. */
- && 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 INTUSE(_dl_lookup_versioned_symbol) (undef_name, undef_map,
- ref, symbol_scope,
- version, type_class, 0);
-
- break;
- }
+ break;
if (__builtin_expect (res, 0) < 0)
{
@@ -451,6 +431,22 @@
*ref = NULL;
return 0;
}
+
+ /* We have to check whether this would bind UNDEF_MAP to an object in
+ the global scope which was dynamically loaded. In this case we have
+ to prevent the latter from being unloaded unless the UNDEF_MAP object
+ is also unloaded. */
+ if (__builtin_expect (current_value.m->l_type == lt_loaded, 0)
+ /* Don't do this for explicit lookups as opposed to implicit runtime
+ lookups. */
+ && ! explicit
+ /* Add UNDEF_MAP to the dependencies. */
+ && 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 INTUSE(_dl_lookup_versioned_symbol) (undef_name, undef_map,
+ ref, symbol_scope,
+ version, type_class, 0);
protected = *ref && ELFW(ST_VISIBILITY) ((*ref)->st_other) == STV_PROTECTED;
Index: elf/reldep7.c
===================================================================
RCS file: elf/reldep7.c
diff -N elf/reldep7.c
--- /dev/null Tue May 5 13:32:27 1998
+++ elf/reldep7.c Sat Feb 16 15:20:42 2002
@@ -0,0 +1,58 @@
+#include <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+main (void)
+{
+ void *h1;
+ void *h2;
+ void *mod1_bar, *mod2_bar;
+
+ h1 = dlopen ("reldep7mod1.so", RTLD_GLOBAL | RTLD_LAZY);
+ if (h1 == NULL)
+ {
+ printf ("cannot open reldep7mod1.so: %s\n", dlerror ());
+ exit (1);
+ }
+
+ h2 = dlopen ("reldep7mod2.so", RTLD_GLOBAL | RTLD_LAZY);
+ if (h2 == NULL)
+ {
+ printf ("cannot open reldep7mod1.so: %s\n", dlerror ());
+ exit (1);
+ }
+
+ mod1_bar = dlsym (h1, "mod1_bar");
+ if (mod1_bar == NULL)
+ {
+ printf ("cannot get address of \"mod1_bar\": %s\n", dlerror ());
+ exit (1);
+ }
+
+ mod2_bar = dlsym (h2, "mod2_bar");
+ if (mod2_bar == NULL)
+ {
+ printf ("cannot get address of \"mod2_bar\": %s\n", dlerror ());
+ exit (1);
+ }
+
+ printf ("%d\n", ((int (*) (void)) mod1_bar) ());
+ printf ("%d\n", ((int (*) (void)) mod2_bar) ());
+
+ if (dlclose (h1) != 0)
+ {
+ printf ("closing h1 failed: %s\n", dlerror ());
+ exit (1);
+ }
+
+ printf ("%d\n", ((int (*) (void)) mod2_bar) ());
+
+ if (dlclose (h2) != 0)
+ {
+ printf ("closing h2 failed: %s\n", dlerror ());
+ exit (1);
+ }
+
+ return 0;
+}
Index: elf/reldep7mod1.c
===================================================================
RCS file: elf/reldep7mod1.c
diff -N elf/reldep7mod1.c
--- /dev/null Tue May 5 13:32:27 1998
+++ elf/reldep7mod1.c Sat Feb 16 15:20:42 2002
@@ -0,0 +1,12 @@
+int foo (void) __attribute__ ((weak));
+int
+foo (void)
+{
+ return 1;
+}
+
+int
+mod1_bar (void)
+{
+ return foo ();
+}
Index: elf/reldep7mod2.c
===================================================================
RCS file: elf/reldep7mod2.c
diff -N elf/reldep7mod2.c
--- /dev/null Tue May 5 13:32:27 1998
+++ elf/reldep7mod2.c Sat Feb 16 15:20:42 2002
@@ -0,0 +1,12 @@
+int foo (void) __attribute__ ((weak));
+int
+foo (void)
+{
+ return 2;
+}
+
+int
+mod2_bar (void)
+{
+ return foo ();
+}
--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE GmbH, Deutschherrnstr. 15-19, D-90429 Nürnberg
Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
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