Re: lt_dlopenext() sets error on succesful loading the library

[Ralf Wildenhues]

* Kurt Roeckx wrote on Sun, Feb 01, 2009 at 08:41:07PM CET:
> On Sun, Feb 01, 2009 at 07:21:11PM +0100, Ralf Wildenhues wrote:
> > * Kurt Roeckx wrote on Fri, Jan 02, 2009 at 12:10:38PM CET:
> > > 
> > > http://bugs.debian.org/510006

> > Before I get to the patches, I would like to have a reproducible test
> > case.  Here's the code I gather from the references (patch against git
> > master).  I've redone the build commands the way I think they are
> > correct (those mentioned in the Autobook are pretty bogus).
> 
> I can only reproduce the error in case there is no .la file.
> I guess the easiest way it to install the library and then remove
> the .la file.  I've attached an updated lt_dlopenext.at and
> a diff against your version that does that, and reproduces
> the error.

Thanks, confirmed.  I'm cleaning up the test a bit (duplicate -rpath in
one of the links), and adding some more variations for more code path
exposure (loading with and without .la file, with absolute or relative
path, or with one of the path variables), adding some portability fixes
(require shared library support for the test, and nonempty MODULE_EXT
for the test without extension), and pushing both your fix and the
testsuite addition.

Thanks again,
Ralf

2009-02-03  Kurt Roeckx <address@hidden>

        lt_dlopenext sets error upon successful library load.
        * libltdl/ltdl.c (lt_dlopenadvise): Fix bogus error on
        successful loading of library with lt_dlopenext.
        Report by Kaiwang Chen in <http://bugs.debian.org/510006>.

diff --git a/libltdl/ltdl.c b/libltdl/ltdl.c
index 6e19599..80b5675 100644
--- a/libltdl/ltdl.c
+++ b/libltdl/ltdl.c
@@ -1614,6 +1614,9 @@ lt_dlopenadvise (const char *filename, lt_dladvise advise)
 {
   lt_dlhandle  handle  = 0;
   int          errors  = 0;
+  const char * saved_error     = 0;
+
+  LT__GETERROR (saved_error);
 
   /* Can't have symbols hidden and visible at the same time!  */
   if (advise && advise->is_symlocal && advise->is_symglobal)
@@ -1650,6 +1653,7 @@ lt_dlopenadvise (const char *filename, lt_dladvise advise)
 
 #if defined(LT_MODULE_EXT)
       /* Try appending SHLIB_EXT.   */
+      LT__SETERRORSTR (saved_error);
       errors = try_dlopen (&handle, filename, shlib_ext, advise);
 
       /* As before, if the file was found but loading failed, return now



2009-02-03  Ralf Wildenhues  <address@hidden>
            Kurt Roeckx <address@hidden>

        New test for lt_dlopenext error message.
        * tests/lt_dlopenext.at (lt_dlopenext error messages): New file,
        with new test, with sources taken from the Autobook example.
        * Makefile.am: Update.

diff --git a/Makefile.am b/Makefile.am
index 0a3e69d..574147d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -478,6 +478,7 @@ TESTSUITE_AT        = tests/testsuite.at \
                  tests/lt_dlexit.at \
                  tests/lt_dladvise.at \
                  tests/lt_dlopen.at \
+                 tests/lt_dlopenext.at \
                  tests/ltdl-api.at \
                  tests/need_lib_prefix.at \
                  tests/standalone.at \
diff --git a/tests/lt_dlopenext.at b/tests/lt_dlopenext.at
new file mode 100644
index 0000000..3d148a9
--- /dev/null
+++ b/tests/lt_dlopenext.at
@@ -0,0 +1,242 @@
+# lt_dlopenext.at -- test libltdl functionality             -*- Autotest -*-
+#
+#   Copyright (C) 2009 Free Software Foundation, Inc.
+#   This file is part of GNU Libtool.
+#
+# GNU Libtool is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of
+# the License, or (at your option) any later version.
+#
+# GNU Libtool 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNU Libtool; see the file COPYING.  If not, a copy
+# can be downloaded from  http://www.gnu.org/licenses/gpl.html,
+# or obtained by writing to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+####
+
+AT_SETUP([lt_dlopenext error messages])
+AT_KEYWORDS([libltdl])
+
+# This test requires shared library support.
+AT_CHECK([$LIBTOOL --features | grep 'enable shared libraries' || exit 77],
+        [], [ignore])
+
+prefix=`pwd`/inst
+libdir=$prefix/lib
+bindir=$prefix/bin
+mkdir $prefix $libdir $bindir
+
+# This code is copied from the Autobook:
+# <http://sources.redhat.com/autobook/autobook/autobook_169.html>
+# so if it needs changes, be sure to notify the Autobook authors
+# about them.
+
+AT_DATA([simple-module.c],
+[[
+#include <stdio.h>
+
+int
+run (const char *argument)
+{
+  printf ("Hello, %s!\n", argument);
+  return 0;
+}
+]])
+
+AT_DATA([ltdl-loader.c],
+[[
+#include <stdio.h>
+#include <stdlib.h>
+#ifndef EXIT_FAILURE
+#  define EXIT_FAILURE        1
+#  define EXIT_SUCCESS        0
+#endif
+
+#include <limits.h>
+#ifndef PATH_MAX
+#  define PATH_MAX 255
+#endif
+
+#include <string.h>
+#include <ltdl.h>
+
+#ifndef MODULE_PATH_ENV
+#  define MODULE_PATH_ENV        "MODULE_PATH"
+#endif
+
+typedef int entrypoint (const char *argument);
+
+/* Save and return a copy of the dlerror() error  message,
+   since the next API call may overwrite the original. */
+static char *dlerrordup (char *errormsg);
+
+int
+main (int argc, const char *argv[])
+{
+  char *errormsg = NULL;
+  lt_dlhandle module = NULL;
+  entrypoint *run = NULL;
+  int errors = 0;
+
+  if (argc != 3)
+    {
+      fprintf (stderr, "USAGE: main MODULENAME ARGUMENT\n");
+      exit (EXIT_FAILURE);
+    }
+
+  /* Initialise libltdl. */
+  errors = lt_dlinit ();
+
+  /* Set the module search path. */
+  if (!errors)
+    {
+      const char *path = getenv (MODULE_PATH_ENV);
+
+      if (path != NULL)
+        errors = lt_dlsetsearchpath (path);
+    }
+
+  /* Load the module. */
+  if (!errors)
+    module = lt_dlopenext (argv[1]);
+
+  /* Find the entry point. */
+  if (module)
+    {
+      run = (entrypoint *) lt_dlsym (module, "run");
+
+      /* In principle, run might legitimately be NULL, so
+         I don't use run == NULL as an error indicator
+         in general. */
+      errormsg = dlerrordup (errormsg);
+      if (errormsg != NULL)
+        {
+          errors = lt_dlclose (module);
+          module = NULL;
+        }
+    }
+  else
+    errors = 1;
+
+  /* Call the entry point function. */
+  if (!errors)
+    {
+      int result = (*run) (argv[2]);
+      if (result < 0)
+        errormsg = strdup ("module entry point execution failed");
+      else
+        printf ("\t=> %d\n", result);
+    }
+
+  /* Unload the module, now that we are done with it. */
+  if (!errors)
+    errors = lt_dlclose (module);
+
+  if (errors)
+    {
+      /* Diagnose the encountered error. */
+      errormsg = dlerrordup (errormsg);
+
+      if (!errormsg)
+        {
+          fprintf (stderr, "%s: dlerror() failed.\n", argv[0]);
+          return EXIT_FAILURE;
+        }
+    }
+
+  /* Finished with ltdl now. */
+  if (!errors)
+    if (lt_dlexit () != 0)
+      errormsg = dlerrordup (errormsg);
+
+  if (errormsg)
+    {
+      fprintf (stderr, "%s: %s.\n", argv[0], errormsg);
+      free (errormsg);
+      exit (EXIT_FAILURE);
+    }
+
+  return EXIT_SUCCESS;
+}
+
+/* Be careful to save a copy of the error message,
+   since the  next API call may overwrite the original. */
+static char *
+dlerrordup (char *errormsg)
+{
+  char *error = (char *) lt_dlerror ();
+  if (error && !errormsg)
+    errormsg = strdup (error);
+  return errormsg;
+}
+]])
+
+: ${LTDLINCL="-I$abs_top_srcdir/libltdl"}
+: ${LIBLTDL="$abs_builddir/../libltdl/libltdlc.la"}
+
+CPPFLAGS="$LTDLINCL $CPPFLAGS"
+LDFLAGS="$LDFLAGS -no-undefined"
+
+AT_CHECK([$LIBTOOL --mode=compile $CC $CPPFLAGS $CFLAGS -c simple-module.c],
+        [], [ignore], [ignore])
+AT_CHECK([$LIBTOOL --mode=link $CC $CFLAGS $LDFLAGS -o simple-module.la ]dnl
+        [simple-module.lo -rpath $libdir -module -avoid-version],
+        [], [ignore], [ignore])
+AT_CHECK([$LIBTOOL --mode=compile $CC $CPPFLAGS $CFLAGS -c ltdl-loader.c],
+        [], [ignore], [ignore])
+AT_CHECK([$LIBTOOL --mode=link $CC $CFLAGS $LDFLAGS -o ltdl-loader$EXEEXT ]dnl
+        [ltdl-loader.$OBJEXT -dlopen self $LIBLTDL],
+        [], [ignore], [ignore])
+AT_CHECK([$LIBTOOL --mode=install cp simple-module.la 
$libdir/simple-module.la], [], [ignore], [ignore])
+AT_CHECK([$LIBTOOL --mode=clean rm -f simple-module.la], [], [ignore], 
[ignore])
+
+# Try finding the module with and without the .la file, with absolute
+# path, relative path, or one of the path variables.  Do not override
+# $PATH for w32, see shlibpath.at for the hacks this requires.
+#
+# Finding the module without the .la file will not work if MODULE_EXT
+# aka. shared_ext is empty.
+
+eval `$LIBTOOL --config | $EGREP '^(shlibpath_var|shrext_cmds)='`
+
+module=no
+eval shared_ext=\"$shrext_cmds\"
+if test -n "$shared_ext"; then
+  have_lafile="with without"
+else
+  have="with"
+fi
+
+if test "$shlibpath_var" = PATH; then
+  $unset shlibpath_var || shlibpath_var=
+fi
+
+for lafile in $have_lafile; do
+  if test $lafile = without; then
+    rm $libdir/simple-module.la
+  fi
+
+  for dir in inst/lib "$libdir"; do
+    LT_AT_EXEC_CHECK([./ltdl-loader], [], [stdout], [ignore],
+                    [$dir/simple-module World])
+    AT_CHECK([grep "Hello, World" stdout], [], [ignore])
+
+    for var in MODULE_PATH LTDL_LIBRARY_PATH $shlibpath_var
+    do
+      eval $var=\$dir
+      export $var
+      LT_AT_EXEC_CHECK([./ltdl-loader], [], [stdout], [ignore],
+                      [simple-module World])
+      AT_CHECK([grep "Hello, World" stdout], [], [ignore])
+      $unset $var || eval $var=
+    done
+  done
+done
+
+AT_CLEANUP