[BZ #15897] dlfcn: do not mark dlopen/dlclose as leaf functions

Since the dlopen funcs might invoke a constructor that calls a func
that is in the same compilation unit as the caller, we cannot mark
them as leaf funcs.

Similarly, dlclose might invoke a destructor that calls a func that
is in the same compilation unit as the caller.

URL: https://sourceware.org/bugzilla/show_bug.cgi?id=15897
Reportedy-by: Fabrice Bauzac <libnoon@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

5 files changed, 142 insertions, 5 deletions

diff --git a/dlfcn/Makefile b/dlfcn/Makefile
index 57a727189d..f3c6df9c1b 100644
--- a/dlfcn/Makefile
+++ b/dlfcn/Makefile
@@ -35,12 +35,13 @@ endif
 ifeq (yes,$(build-shared))
 tests = glrefmain failtest tst-dladdr default errmsg1 tstcxaatexit \
 	bug-dlopen1 bug-dlsym1 tst-dlinfo bug-atexit1 bug-atexit2 \
-	bug-atexit3 tstatexit
+	bug-atexit3 tstatexit bug-dl-leaf
 endif
 modules-names = glreflib1 glreflib2 glreflib3 failtestmod defaultmod1 \
 		defaultmod2 errmsg1mod modatexit modcxaatexit \
 		bug-dlsym1-lib1 bug-dlsym1-lib2 bug-atexit1-lib \
-		bug-atexit2-lib bug-atexit3-lib
+		bug-atexit2-lib bug-atexit3-lib bug-dl-leaf-lib \
+		bug-dl-leaf-lib-cb
 
 failtestmod.so-no-z-defs = yes
 glreflib2.so-no-z-defs = yes
@@ -132,3 +133,8 @@ $(objpfx)bug-atexit2.out: $(objpfx)bug-atexit2-lib.so
 LDLIBS-bug-atexit3-lib.so = -lstdc++ -lgcc_eh
 $(objpfx)bug-atexit3: $(libdl)
 $(objpfx)bug-atexit3.out: $(objpfx)bug-atexit3-lib.so
+
+$(objpfx)bug-dl-leaf: $(objpfx)bug-dl-leaf-lib.so
+$(objpfx)bug-dl-leaf.out: $(objpfx)bug-dl-leaf-lib-cb.so
+$(objpfx)bug-dl-leaf-lib.so: $(libdl)
+$(objpfx)bug-dl-leaf-lib-cb.so: $(objpfx)bug-dl-leaf-lib.so
diff --git a/dlfcn/bug-dl-leaf-lib-cb.c b/dlfcn/bug-dl-leaf-lib-cb.c
new file mode 100644
index 0000000000..e028c047a5
--- /dev/null
+++ b/dlfcn/bug-dl-leaf-lib-cb.c
@@ -0,0 +1,35 @@
+/* Make sure dlopen/dlclose are not marked as leaf functions.
+   See bug-dl-leaf-lib.c for details.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Mike Frysinger <vapier@gentoo.org>
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+extern void check_val_init (void);
+extern void check_val_fini (void);
+
+__attribute__ ((__constructor__))
+void construct (void)
+{
+  check_val_init ();
+}
+
+__attribute__ ((__destructor__))
+void destruct (void)
+{
+  check_val_fini ();
+}
diff --git a/dlfcn/bug-dl-leaf-lib.c b/dlfcn/bug-dl-leaf-lib.c
new file mode 100644
index 0000000000..e5955422d1
--- /dev/null
+++ b/dlfcn/bug-dl-leaf-lib.c
@@ -0,0 +1,71 @@
+/* Make sure dlopen/dlclose are not marked as leaf functions.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Mike Frysinger <vapier@gentoo.org>
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* The bug-dl-leaf.c file will call our lib_main directly.  We do this to
+   keep things simple -- no need to use --export-dynamic with the linker
+   or build the main ELF as a PIE.
+
+   The lib_main func will modify some of its state while dlopening and
+   dlclosing the bug-dl-leaf-lib-cb.so library.  The constructors and
+   destructors in that library will call back into this library to also
+   muck with state (the check_val_xxx funcs).
+
+   If dlclose/dlopen are marked as "leaf" functions, then with newer
+   versions of gcc, the state modification won't work correctly.  */
+
+#include <assert.h>
+#include <dlfcn.h>
+
+static int val = 1;
+static int called = 0;
+
+void check_val_init (void)
+{
+  called = 1;
+  assert (val == 2);
+}
+
+void check_val_fini (void)
+{
+  called = 2;
+  assert (val == 4);
+}
+
+int lib_main (void)
+{
+  int ret;
+  void *hdl;
+
+  /* Make sure the constructor sees the updated val.  */
+  val = 2;
+  hdl = dlopen ("bug-dl-leaf-lib-cb.so", RTLD_GLOBAL | RTLD_LAZY);
+  val = 3;
+  assert (hdl);
+  assert (called == 1);
+
+  /* Make sure the destructor sees the updated val.  */
+  val = 4;
+  ret = dlclose (hdl);
+  val = 5;
+  assert (ret == 0);
+  assert (called == 2);
+
+  return !val;
+}
diff --git a/dlfcn/bug-dl-leaf.c b/dlfcn/bug-dl-leaf.c
new file mode 100644
index 0000000000..c3fbe757fb
--- /dev/null
+++ b/dlfcn/bug-dl-leaf.c
@@ -0,0 +1,25 @@
+/* Make sure dlopen/dlclose are not marked as leaf functions.
+   See bug-dl-leaf-lib.c for details.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Mike Frysinger <vapier@gentoo.org>
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define TEST_FUNCTION lib_main ()
+extern int lib_main (void);
+
+#include "../test-skeleton.c"
diff --git a/dlfcn/dlfcn.h b/dlfcn/dlfcn.h
index 241b554165..1ed47b1d1e 100644
--- a/dlfcn/dlfcn.h
+++ b/dlfcn/dlfcn.h
@@ -53,11 +53,11 @@ __BEGIN_DECLS
 
 /* Open the shared object FILE and map it in; return a handle that can be
    passed to `dlsym' to get symbol values from it.  */
-extern void *dlopen (const char *__file, int __mode) __THROW;
+extern void *dlopen (const char *__file, int __mode) __THROWNL;
 
 /* Unmap and close a shared object opened by `dlopen'.
    The handle cannot be used again after calling `dlclose'.  */
-extern int dlclose (void *__handle) __THROW __nonnull ((1));
+extern int dlclose (void *__handle) __THROWNL __nonnull ((1));
 
 /* Find the run-time address in the shared object HANDLE refers to
    of the symbol called NAME.  */
@@ -66,7 +66,7 @@ extern void *dlsym (void *__restrict __handle,
 
 #ifdef __USE_GNU
 /* Like `dlopen', but request object to be allocated in a new namespace.  */
-extern void *dlmopen (Lmid_t __nsid, const char *__file, int __mode) __THROW;
+extern void *dlmopen (Lmid_t __nsid, const char *__file, int __mode) __THROWNL;
 
 /* Find the run-time address in the shared object HANDLE refers to
    of the symbol called NAME with VERSION.  */