glibc/elf/tst-dlmopen-dlerror.c

/* Check that dlfcn errors are reported properly after dlmopen.
   Copyright (C) 2021 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 <stddef.h>
#include <string.h>
#include <support/check.h>
#include <support/xdlfcn.h>

static int
do_test (void)
{
  void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-dlerror-mod.so",
                           RTLD_NOW);
  void (*call_dlsym) (const char *name) = xdlsym (handle, "call_dlsym");
  void (*call_dlopen) (const char *name) = xdlsym (handle, "call_dlopen");

  /* Iterate over various name lengths.  This changes the size of
     error messages allocated by ld.so and has been shown to trigger
     detectable heap corruption if malloc/free calls in different
     namespaces are mixed.  */
  char buffer[2048];
  char *buffer_end = &buffer[sizeof (buffer) - 2];
  for (char *p = stpcpy (buffer, "does not exist "); p < buffer_end; ++p)
    {
      p[0] = 'X';
      p[1] = '\0';
      call_dlsym (buffer);
      call_dlopen (buffer);
    }

  return 0;
}

#include <support/test-driver.c>