glibc/elf/tst-nodelete-dlclose-dso.c
Carlos O'Donell 57707b7fcc Bug 11941: ld.so: Improper assert map->l_init_called in dlclose
There is at least one use case where during exit a library destructor
might call dlclose() on a valid handle and have it fail with an
assertion. We must allow this case, it is a valid handle, and dlclose()
should not fail with an assert. In the future we might be able to return
an error that the dlclose() could not be completed because the opened
library has already been unloaded and destructors have run as part of
exit processing.

For more details see:
https://www.sourceware.org/ml/libc-alpha/2016-12/msg00859.html
2016-12-23 13:30:22 -05:00

91 lines
2.7 KiB
C

/* Bug 11941: Improper assert map->l_init_called in dlclose.
Copyright (C) 2016 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/>. */
/* This is the primary DSO that is loaded by the appliation. This DSO
then loads a plugin with RTLD_NODELETE. This plugin depends on this
DSO. This dependency chain means that at application shutdown the
plugin will be destructed first. Thus by the time this DSO is
destructed we will be calling dlclose on an object that has already
been destructed. It is allowed to call dlclose in this way and
should not assert. */
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
/* Plugin to load. */
static void *plugin_lib = NULL;
/* Plugin function. */
static void (*plugin_func) (void);
#define LIB_PLUGIN "tst-nodelete-dlclose-plugin.so"
/* This function is never called but the plugin references it.
We do this to avoid any future --as-needed from removing the
plugin's DT_NEEDED on this DSO (required for the test). */
void
primary_reference (void)
{
printf ("INFO: Called primary_reference function.\n");
}
void
primary (void)
{
char *error;
plugin_lib = dlopen (LIB_PLUGIN, RTLD_NOW | RTLD_LOCAL | RTLD_NODELETE);
if (plugin_lib == NULL)
{
printf ("ERROR: Unable to load plugin library.\n");
exit (EXIT_FAILURE);
}
dlerror ();
plugin_func = (void (*) (void)) dlsym (plugin_lib, "plugin_func");
error = dlerror ();
if (error != NULL)
{
printf ("ERROR: Unable to find symbol with error \"%s\".",
error);
exit (EXIT_FAILURE);
}
return;
}
__attribute__ ((destructor))
static void
primary_dtor (void)
{
int ret;
printf ("INFO: Calling primary destructor.\n");
/* The destructor runs in the test driver also, which
hasn't called primary, in that case do nothing. */
if (plugin_lib == NULL)
return;
ret = dlclose (plugin_lib);
if (ret != 0)
{
printf ("ERROR: Calling dlclose failed with \"%s\"\n",
dlerror ());
exit (EXIT_FAILURE);
}
}