Implement xdlopen, xdlsym and xdlclose routines which terminate test

program with appropriate message if the corresponding dlfcn.h routine
returns an error.

Use them in stdlib/tst-tls-atexit.c

ChangeLog

@@ -1,3 +1,11 @@
+2017-09-20  Paul Pluzhnikov  <ppluzhnikov@google.com>
+	    Carlos O'Donell  <carlos@redhat.com>
+
+	* support/xdlfcn.h: New file.
+	* support/xdlfcn.c: New file.
+	* support/Makefile (libsupport-routines): Add xdlfcn.
+	* stdlib/tst-tls-atexit.c: Use xdlopen, xdlsym, xdlclose.
+
 2017-09-20  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #20142]

stdlib/tst-tls-atexit.c

@@ -31,7 +31,6 @@
    second handle.  In the end, the DSO should remain loaded due to the
    RTLD_NODELETE flag being set in the second dlopen call.  */
 
-#include <dlfcn.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -39,6 +38,7 @@
 #include <errno.h>
 #include <link.h>
 #include <stdbool.h>
+#include <support/xdlfcn.h>
 
 #ifndef NO_DELETE
 # define LOADED_IS_GOOD false
@@ -73,18 +73,12 @@ is_loaded (void)
 static void *
 reg_dtor_and_close (void *h)
 {
-  void (*reg_dtor) (void) = (void (*) (void)) dlsym (h, "reg_dtor");
+  void (*reg_dtor) (void) = (void (*) (void)) xdlsym (h, "reg_dtor");
-
-  if (reg_dtor == NULL)
-    {
-      printf ("Unable to find symbol: %s\n", dlerror ());
-      return (void *) (uintptr_t) 1;
-    }
 
   reg_dtor ();
 
 #ifndef NO_DELETE
-  dlclose (h);
+  xdlclose (h);
 #endif
 
   return NULL;
@@ -119,32 +113,22 @@ static int
 do_test (void)
 {
   /* Load the DSO.  */
-  void *h1 = dlopen (DSO_NAME, RTLD_LAZY);
+  void *h1 = xdlopen (DSO_NAME, RTLD_LAZY);
-  if (h1 == NULL)
-    {
-      printf ("h1: Unable to load DSO: %s\n", dlerror ());
-      return 1;
-    }
 
 #ifndef NO_DELETE
   if (spawn_thread (h1) != 0)
     return 1;
 #endif
 
-  void *h2 = dlopen (DSO_NAME, H2_RTLD_FLAGS);
+  void *h2 = xdlopen (DSO_NAME, H2_RTLD_FLAGS);
-  if (h2 == NULL)
-    {
-      printf ("h2: Unable to load DSO: %s\n", dlerror ());
-      return 1;
-    }
 
 #ifdef NO_DELETE
   if (spawn_thread (h1) != 0)
     return 1;
 
-  dlclose (h1);
+  xdlclose (h1);
 #endif
-  dlclose (h2);
+  xdlclose (h2);
 
   /* Check link maps to ensure that the DSO has unloaded.  In the normal case,
      the DSO should be unloaded if there are no uses.  However, if one of the

support/Makefile

@@ -65,6 +65,7 @@ libsupport-routines = \
   xchroot \
   xclose \
   xconnect \
+  xdlfcn \
   xdup2 \
   xfclose \
   xfopen \

support/xdlfcn.c

@@ -0,0 +1,58 @@
+/* Support functionality for using dlopen/dlclose/dlsym.
+   Copyright (C) 2017 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 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/>.  */
+
+#include <support/check.h>
+#include <support/xdlfcn.h>
+
+void *
+xdlopen (const char *filename, int flags)
+{
+  void *dso = dlopen (filename, flags);
+
+  if (dso == NULL)
+    FAIL_EXIT1 ("error: dlopen: %s\n", dlerror ());
+
+  /* Clear any errors.  */
+  dlerror ();
+
+  return dso;
+}
+
+void *
+xdlsym (void *handle, const char *symbol)
+{
+  void *sym = dlsym (handle, symbol);
+
+  if (sym == NULL)
+    FAIL_EXIT1 ("error: dlsym: %s\n", dlerror ());
+
+  /* Clear any errors.  */
+  dlerror ();
+
+  return sym;
+}
+
+void
+xdlclose (void *handle)
+{
+  if (dlclose (handle) != 0)
+    FAIL_EXIT1 ("error: dlclose: %s\n", dlerror ());
+
+  /* Clear any errors.  */
+  dlerror ();
+}

support/xdlfcn.h

@@ -0,0 +1,34 @@
+/* Support functionality for using dlopen/dlclose/dlsym.
+   Copyright (C) 2017 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 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/>.  */
+
+#ifndef SUPPORT_DLOPEN_H
+#define SUPPORT_DLOPEN_H
+
+#include <dlfcn.h>
+
+__BEGIN_DECLS
+
+/* Each of these terminates process on failure with relevant error message.  */
+void *xdlopen (const char *filename, int flags);
+void *xdlsym (void *handle, const char *symbol);
+void xdlclose (void *handle);
+
+
+__END_DECLS
+
+#endif /* SUPPORT_DLOPEN_H */