glib/gmodule/gmodule-dl.c
Justin Kim 7e70dd88c9 gmodule: Use RTLD_DEFAULT if defined __BIONIC__
This is a partial change of the previous work[0].
On 64 bit Android since android-23, 'handle = dlopen(NULL); dlsym(handle)'
doesn't work. Instead, only 'dlsym(RTLD_DEFAULT)' returns a valid pointer.

However, RTLD_DEFAULT is defined as '(void *) 0x0' on 64bit Android which
is usually used for invalid value so this patch allows the specific case.

[0] 0d81bb4e31

https://bugzilla.gnome.org/show_bug.cgi?id=788270
2017-10-06 21:09:47 +03:00

185 lines
4.8 KiB
C

/* GMODULE - GLIB wrapper code for dynamic module loading
* Copyright (C) 1998, 2000 Tim Janik
*
* This 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.
*
* This 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 this library; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* Modified by the GLib Team and others 1997-2000. See the AUTHORS
* file for a list of people on the GLib Team. See the ChangeLog
* files for a list of changes. These files are distributed with
* GLib at ftp://ftp.gtk.org/pub/gtk/.
*/
/*
* MT safe
*/
#include "config.h"
#include <dlfcn.h>
/* Perl includes <nlist.h> and <link.h> instead of <dlfcn.h> on some systmes? */
/* dlerror() is not implemented on all systems
*/
#ifndef G_MODULE_HAVE_DLERROR
# ifdef __NetBSD__
# define dlerror() g_strerror (errno)
# else /* !__NetBSD__ */
/* could we rely on errno's state here? */
# define dlerror() "unknown dl-error"
# endif /* !__NetBSD__ */
#endif /* G_MODULE_HAVE_DLERROR */
/* some flags are missing on some systems, so we provide
* harmless defaults.
* The Perl sources say, RTLD_LAZY needs to be defined as (1),
* at least for Solaris 1.
*
* Mandatory:
* RTLD_LAZY - resolve undefined symbols as code from the dynamic library
* is executed.
* RTLD_NOW - resolve all undefined symbols before dlopen returns, and fail
* if this cannot be done.
* Optionally:
* RTLD_GLOBAL - the external symbols defined in the library will be made
* available to subsequently loaded libraries.
*/
#ifndef HAVE_RTLD_LAZY
#define RTLD_LAZY 1
#endif /* RTLD_LAZY */
#ifndef HAVE_RTLD_NOW
#define RTLD_NOW 0
#endif /* RTLD_NOW */
/* some systems (OSF1 V5.0) have broken RTLD_GLOBAL linkage */
#ifdef G_MODULE_BROKEN_RTLD_GLOBAL
#undef RTLD_GLOBAL
#undef HAVE_RTLD_GLOBAL
#endif /* G_MODULE_BROKEN_RTLD_GLOBAL */
#ifndef HAVE_RTLD_GLOBAL
#define RTLD_GLOBAL 0
#endif /* RTLD_GLOBAL */
/* --- functions --- */
static gchar*
fetch_dlerror (gboolean replace_null)
{
gchar *msg = dlerror ();
/* make sure we always return an error message != NULL, if
* expected to do so. */
if (!msg && replace_null)
return "unknown dl-error";
return msg;
}
static gpointer
_g_module_open (const gchar *file_name,
gboolean bind_lazy,
gboolean bind_local)
{
gpointer handle;
handle = dlopen (file_name,
(bind_local ? 0 : RTLD_GLOBAL) | (bind_lazy ? RTLD_LAZY : RTLD_NOW));
if (!handle)
g_module_set_error (fetch_dlerror (TRUE));
return handle;
}
static gpointer
_g_module_self (void)
{
gpointer handle;
/* to query symbols from the program itself, special link options
* are required on some systems.
*/
/* On Android 32 bit (i.e. not __LP64__), dlopen(NULL)
* does not work reliable and generally no symbols are found
* at all. RTLD_DEFAULT works though.
* On Android 64 bit, dlopen(NULL) seems to work but dlsym(handle)
* always returns 'undefined symbol'. Only if RTLD_DEFAULT or
* NULL is given, dlsym returns an appropriate pointer.
*/
#if defined(__BIONIC__)
handle = RTLD_DEFAULT;
#else
handle = dlopen (NULL, RTLD_GLOBAL | RTLD_LAZY);
#endif
if (!handle)
g_module_set_error (fetch_dlerror (TRUE));
return handle;
}
static void
_g_module_close (gpointer handle,
gboolean is_unref)
{
/* are there any systems out there that have dlopen()/dlclose()
* without a reference count implementation?
*
* See above for the Android special case
*/
#if defined(__BIONIC__)
is_unref = (handle != RTLD_DEFAULT);
#else
is_unref |= 1;
#endif
if (is_unref)
{
if (dlclose (handle) != 0)
g_module_set_error (fetch_dlerror (TRUE));
}
}
static gpointer
_g_module_symbol (gpointer handle,
const gchar *symbol_name)
{
gpointer p;
gchar *msg;
fetch_dlerror (FALSE);
p = dlsym (handle, symbol_name);
msg = fetch_dlerror (FALSE);
if (msg)
g_module_set_error (msg);
return p;
}
static gchar*
_g_module_build_path (const gchar *directory,
const gchar *module_name)
{
if (directory && *directory) {
if (strncmp (module_name, "lib", 3) == 0)
return g_strconcat (directory, "/", module_name, NULL);
else
return g_strconcat (directory, "/lib", module_name, "." G_MODULE_SUFFIX, NULL);
} else if (strncmp (module_name, "lib", 3) == 0)
return g_strdup (module_name);
else
return g_strconcat ("lib", module_name, "." G_MODULE_SUFFIX, NULL);
}