glib/gmodule/gmodule.c
Emmanuele Bassi 08f0a31289 Revert "Remove all uses of G_CONST_RETURN"
This reverts commit 36741245cc.

The removal has not been discussed, except on Bugzilla:

https://bugzilla.gnome.org/show_bug.cgi?id=644611
2011-03-15 09:03:28 +00:00

687 lines
17 KiB
C

/* GMODULE - GLIB wrapper code for dynamic module loading
* Copyright (C) 1998 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 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/*
* 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 "glib.h"
#include "gmodule.h"
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef G_OS_WIN32
#include <io.h> /* For open() and close() prototypes. */
#endif
#include "gmoduleconf.h"
#include "gstdio.h"
/* We maintain a list of modules, so we can reference count them.
* That's needed because some platforms don't support refernce counts on
* modules e.g. the shl_* implementation of HP-UX
* (http://www.stat.umn.edu/~luke/xls/projects/dlbasics/dlbasics.html).
* Also, the module for the program itself is kept seperatedly for
* faster access and because it has special semantics.
*/
/* --- structures --- */
struct _GModule
{
gchar *file_name;
#if defined (G_OS_WIN32) && !defined(_WIN64)
gchar *cp_file_name;
#endif
gpointer handle;
guint ref_count : 31;
guint is_resident : 1;
GModuleUnload unload;
GModule *next;
};
/* --- prototypes --- */
static gpointer _g_module_open (const gchar *file_name,
gboolean bind_lazy,
gboolean bind_local);
static void _g_module_close (gpointer handle,
gboolean is_unref);
static gpointer _g_module_self (void);
static gpointer _g_module_symbol (gpointer handle,
const gchar *symbol_name);
static gchar* _g_module_build_path (const gchar *directory,
const gchar *module_name);
static inline void g_module_set_error (const gchar *error);
static inline GModule* g_module_find_by_handle (gpointer handle);
static inline GModule* g_module_find_by_name (const gchar *name);
/* --- variables --- */
static GModule *modules = NULL;
static GModule *main_module = NULL;
static GStaticPrivate module_error_private = G_STATIC_PRIVATE_INIT;
static gboolean module_debug_initialized = FALSE;
static guint module_debug_flags = 0;
/* --- inline functions --- */
static inline GModule*
g_module_find_by_handle (gpointer handle)
{
GModule *module;
GModule *retval = NULL;
if (main_module && main_module->handle == handle)
retval = main_module;
else
for (module = modules; module; module = module->next)
if (handle == module->handle)
{
retval = module;
break;
}
return retval;
}
static inline GModule*
g_module_find_by_name (const gchar *name)
{
GModule *module;
GModule *retval = NULL;
for (module = modules; module; module = module->next)
if (strcmp (name, module->file_name) == 0)
{
retval = module;
break;
}
return retval;
}
static inline void
g_module_set_error_unduped (gchar *error)
{
g_static_private_set (&module_error_private, error, g_free);
errno = 0;
}
static inline void
g_module_set_error (const gchar *error)
{
g_module_set_error_unduped (g_strdup (error));
}
/* --- include platform specifc code --- */
#define SUPPORT_OR_RETURN(rv) { g_module_set_error (NULL); }
#if (G_MODULE_IMPL == G_MODULE_IMPL_DL)
#include "gmodule-dl.c"
#elif (G_MODULE_IMPL == G_MODULE_IMPL_DLD)
#include "gmodule-dld.c"
#elif (G_MODULE_IMPL == G_MODULE_IMPL_WIN32)
#include "gmodule-win32.c"
#elif (G_MODULE_IMPL == G_MODULE_IMPL_DYLD)
#include "gmodule-dyld.c"
#elif (G_MODULE_IMPL == G_MODULE_IMPL_AR)
#include "gmodule-ar.c"
#else
#undef SUPPORT_OR_RETURN
#define SUPPORT_OR_RETURN(rv) { g_module_set_error ("dynamic modules are " \
"not supported by this system"); return rv; }
static gpointer
_g_module_open (const gchar *file_name,
gboolean bind_lazy,
gboolean bind_local)
{
return NULL;
}
static void
_g_module_close (gpointer handle,
gboolean is_unref)
{
}
static gpointer
_g_module_self (void)
{
return NULL;
}
static gpointer
_g_module_symbol (gpointer handle,
const gchar *symbol_name)
{
return NULL;
}
static gchar*
_g_module_build_path (const gchar *directory,
const gchar *module_name)
{
return NULL;
}
#endif /* no implementation */
/* --- functions --- */
gboolean
g_module_supported (void)
{
SUPPORT_OR_RETURN (FALSE);
return TRUE;
}
static gchar*
parse_libtool_archive (const gchar* libtool_name)
{
const guint TOKEN_DLNAME = G_TOKEN_LAST + 1;
const guint TOKEN_INSTALLED = G_TOKEN_LAST + 2;
const guint TOKEN_LIBDIR = G_TOKEN_LAST + 3;
gchar *lt_dlname = NULL;
gboolean lt_installed = TRUE;
gchar *lt_libdir = NULL;
gchar *name;
GTokenType token;
GScanner *scanner;
int fd = g_open (libtool_name, O_RDONLY, 0);
if (fd < 0)
{
gchar *display_libtool_name = g_filename_display_name (libtool_name);
g_module_set_error_unduped (g_strdup_printf ("failed to open libtool archive \"%s\"", display_libtool_name));
g_free (display_libtool_name);
return NULL;
}
/* search libtool's dlname specification */
scanner = g_scanner_new (NULL);
g_scanner_input_file (scanner, fd);
scanner->config->symbol_2_token = TRUE;
g_scanner_scope_add_symbol (scanner, 0, "dlname",
GUINT_TO_POINTER (TOKEN_DLNAME));
g_scanner_scope_add_symbol (scanner, 0, "installed",
GUINT_TO_POINTER (TOKEN_INSTALLED));
g_scanner_scope_add_symbol (scanner, 0, "libdir",
GUINT_TO_POINTER (TOKEN_LIBDIR));
while (!g_scanner_eof (scanner))
{
token = g_scanner_get_next_token (scanner);
if (token == TOKEN_DLNAME || token == TOKEN_INSTALLED ||
token == TOKEN_LIBDIR)
{
if (g_scanner_get_next_token (scanner) != '=' ||
g_scanner_get_next_token (scanner) !=
(token == TOKEN_INSTALLED ?
G_TOKEN_IDENTIFIER : G_TOKEN_STRING))
{
gchar *display_libtool_name = g_filename_display_name (libtool_name);
g_module_set_error_unduped (g_strdup_printf ("unable to parse libtool archive \"%s\"", display_libtool_name));
g_free (display_libtool_name);
g_free (lt_dlname);
g_free (lt_libdir);
g_scanner_destroy (scanner);
close (fd);
return NULL;
}
else
{
if (token == TOKEN_DLNAME)
{
g_free (lt_dlname);
lt_dlname = g_strdup (scanner->value.v_string);
}
else if (token == TOKEN_INSTALLED)
lt_installed =
strcmp (scanner->value.v_identifier, "yes") == 0;
else /* token == TOKEN_LIBDIR */
{
g_free (lt_libdir);
lt_libdir = g_strdup (scanner->value.v_string);
}
}
}
}
if (!lt_installed)
{
gchar *dir = g_path_get_dirname (libtool_name);
g_free (lt_libdir);
lt_libdir = g_strconcat (dir, G_DIR_SEPARATOR_S ".libs", NULL);
g_free (dir);
}
name = g_strconcat (lt_libdir, G_DIR_SEPARATOR_S, lt_dlname, NULL);
g_free (lt_dlname);
g_free (lt_libdir);
g_scanner_destroy (scanner);
close (fd);
return name;
}
static inline gboolean
str_check_suffix (const gchar* string,
const gchar* suffix)
{
gsize string_len = strlen (string);
gsize suffix_len = strlen (suffix);
return string_len >= suffix_len &&
strcmp (string + string_len - suffix_len, suffix) == 0;
}
enum
{
G_MODULE_DEBUG_RESIDENT_MODULES = 1 << 0,
G_MODULE_DEBUG_BIND_NOW_MODULES = 1 << 1
};
static void
_g_module_debug_init (void)
{
const GDebugKey keys[] = {
{ "resident-modules", G_MODULE_DEBUG_RESIDENT_MODULES },
{ "bind-now-modules", G_MODULE_DEBUG_BIND_NOW_MODULES }
};
const gchar *env;
env = g_getenv ("G_DEBUG");
module_debug_flags =
!env ? 0 : g_parse_debug_string (env, keys, G_N_ELEMENTS (keys));
module_debug_initialized = TRUE;
}
static GStaticRecMutex g_module_global_lock = G_STATIC_REC_MUTEX_INIT;
GModule*
g_module_open (const gchar *file_name,
GModuleFlags flags)
{
GModule *module;
gpointer handle = NULL;
gchar *name = NULL;
SUPPORT_OR_RETURN (NULL);
g_static_rec_mutex_lock (&g_module_global_lock);
if (G_UNLIKELY (!module_debug_initialized))
_g_module_debug_init ();
if (module_debug_flags & G_MODULE_DEBUG_BIND_NOW_MODULES)
flags &= ~G_MODULE_BIND_LAZY;
if (!file_name)
{
if (!main_module)
{
handle = _g_module_self ();
if (handle)
{
main_module = g_new (GModule, 1);
main_module->file_name = NULL;
#if defined (G_OS_WIN32) && !defined(_WIN64)
main_module->cp_file_name = NULL;
#endif
main_module->handle = handle;
main_module->ref_count = 1;
main_module->is_resident = TRUE;
main_module->unload = NULL;
main_module->next = NULL;
}
}
else
main_module->ref_count++;
g_static_rec_mutex_unlock (&g_module_global_lock);
return main_module;
}
/* we first search the module list by name */
module = g_module_find_by_name (file_name);
if (module)
{
module->ref_count++;
g_static_rec_mutex_unlock (&g_module_global_lock);
return module;
}
/* check whether we have a readable file right away */
if (g_file_test (file_name, G_FILE_TEST_IS_REGULAR))
name = g_strdup (file_name);
/* try completing file name with standard library suffix */
if (!name)
{
name = g_strconcat (file_name, "." G_MODULE_SUFFIX, NULL);
if (!g_file_test (name, G_FILE_TEST_IS_REGULAR))
{
g_free (name);
name = NULL;
}
}
/* try completing by appending libtool suffix */
if (!name)
{
name = g_strconcat (file_name, ".la", NULL);
if (!g_file_test (name, G_FILE_TEST_IS_REGULAR))
{
g_free (name);
name = NULL;
}
}
/* we can't access() the file, lets hope the platform backends finds
* it via library paths
*/
if (!name)
{
gchar *dot = strrchr (file_name, '.');
gchar *slash = strrchr (file_name, G_DIR_SEPARATOR);
/* make sure the name has a suffix */
if (!dot || dot < slash)
name = g_strconcat (file_name, "." G_MODULE_SUFFIX, NULL);
else
name = g_strdup (file_name);
}
/* ok, try loading the module */
if (name)
{
/* if it's a libtool archive, figure library file to load */
if (str_check_suffix (name, ".la")) /* libtool archive? */
{
gchar *real_name = parse_libtool_archive (name);
/* real_name might be NULL, but then module error is already set */
if (real_name)
{
g_free (name);
name = real_name;
}
}
if (name)
handle = _g_module_open (name, (flags & G_MODULE_BIND_LAZY) != 0,
(flags & G_MODULE_BIND_LOCAL) != 0);
}
else
{
gchar *display_file_name = g_filename_display_name (file_name);
g_module_set_error_unduped (g_strdup_printf ("unable to access file \"%s\"", display_file_name));
g_free (display_file_name);
}
g_free (name);
if (handle)
{
gchar *saved_error;
GModuleCheckInit check_init;
const gchar *check_failed = NULL;
/* search the module list by handle, since file names are not unique */
module = g_module_find_by_handle (handle);
if (module)
{
_g_module_close (module->handle, TRUE);
module->ref_count++;
g_module_set_error (NULL);
g_static_rec_mutex_unlock (&g_module_global_lock);
return module;
}
saved_error = g_strdup (g_module_error ());
g_module_set_error (NULL);
module = g_new (GModule, 1);
module->file_name = g_strdup (file_name);
#if defined (G_OS_WIN32) && !defined(_WIN64)
module->cp_file_name = g_locale_from_utf8 (file_name, -1,
NULL, NULL, NULL);
#endif
module->handle = handle;
module->ref_count = 1;
module->is_resident = FALSE;
module->unload = NULL;
module->next = modules;
modules = module;
/* check initialization */
if (g_module_symbol (module, "g_module_check_init", (gpointer) &check_init) && check_init != NULL)
check_failed = check_init (module);
/* we don't call unload() if the initialization check failed. */
if (!check_failed)
g_module_symbol (module, "g_module_unload", (gpointer) &module->unload);
if (check_failed)
{
gchar *error;
error = g_strconcat ("GModule (",
file_name ? file_name : "NULL",
") initialization check failed: ",
check_failed, NULL);
g_module_close (module);
module = NULL;
g_module_set_error (error);
g_free (error);
}
else
g_module_set_error (saved_error);
g_free (saved_error);
}
if (module != NULL &&
(module_debug_flags & G_MODULE_DEBUG_RESIDENT_MODULES))
g_module_make_resident (module);
g_static_rec_mutex_unlock (&g_module_global_lock);
return module;
}
#if defined (G_OS_WIN32) && !defined(_WIN64)
#undef g_module_open
GModule*
g_module_open (const gchar *file_name,
GModuleFlags flags)
{
gchar *utf8_file_name = g_locale_to_utf8 (file_name, -1, NULL, NULL, NULL);
GModule *retval = g_module_open_utf8 (utf8_file_name, flags);
g_free (utf8_file_name);
return retval;
}
#endif
gboolean
g_module_close (GModule *module)
{
SUPPORT_OR_RETURN (FALSE);
g_return_val_if_fail (module != NULL, FALSE);
g_return_val_if_fail (module->ref_count > 0, FALSE);
g_static_rec_mutex_lock (&g_module_global_lock);
module->ref_count--;
if (!module->ref_count && !module->is_resident && module->unload)
{
GModuleUnload unload;
unload = module->unload;
module->unload = NULL;
unload (module);
}
if (!module->ref_count && !module->is_resident)
{
GModule *last;
GModule *node;
last = NULL;
node = modules;
while (node)
{
if (node == module)
{
if (last)
last->next = node->next;
else
modules = node->next;
break;
}
last = node;
node = last->next;
}
module->next = NULL;
_g_module_close (module->handle, FALSE);
g_free (module->file_name);
#if defined (G_OS_WIN32) && !defined(_WIN64)
g_free (module->cp_file_name);
#endif
g_free (module);
}
g_static_rec_mutex_unlock (&g_module_global_lock);
return g_module_error() == NULL;
}
void
g_module_make_resident (GModule *module)
{
g_return_if_fail (module != NULL);
module->is_resident = TRUE;
}
G_CONST_RETURN gchar*
g_module_error (void)
{
return g_static_private_get (&module_error_private);
}
gboolean
g_module_symbol (GModule *module,
const gchar *symbol_name,
gpointer *symbol)
{
const gchar *module_error;
if (symbol)
*symbol = NULL;
SUPPORT_OR_RETURN (FALSE);
g_return_val_if_fail (module != NULL, FALSE);
g_return_val_if_fail (symbol_name != NULL, FALSE);
g_return_val_if_fail (symbol != NULL, FALSE);
g_static_rec_mutex_lock (&g_module_global_lock);
#ifdef G_MODULE_NEED_USCORE
{
gchar *name;
name = g_strconcat ("_", symbol_name, NULL);
*symbol = _g_module_symbol (module->handle, name);
g_free (name);
}
#else /* !G_MODULE_NEED_USCORE */
*symbol = _g_module_symbol (module->handle, symbol_name);
#endif /* !G_MODULE_NEED_USCORE */
module_error = g_module_error ();
if (module_error)
{
gchar *error;
error = g_strconcat ("`", symbol_name, "': ", module_error, NULL);
g_module_set_error (error);
g_free (error);
*symbol = NULL;
}
g_static_rec_mutex_unlock (&g_module_global_lock);
return !module_error;
}
G_CONST_RETURN gchar*
g_module_name (GModule *module)
{
g_return_val_if_fail (module != NULL, NULL);
if (module == main_module)
return "main";
return module->file_name;
}
#if defined (G_OS_WIN32) && !defined(_WIN64)
#undef g_module_name
G_CONST_RETURN gchar*
g_module_name (GModule *module)
{
g_return_val_if_fail (module != NULL, NULL);
if (module == main_module)
return "main";
return module->cp_file_name;
}
#endif
gchar*
g_module_build_path (const gchar *directory,
const gchar *module_name)
{
g_return_val_if_fail (module_name != NULL, NULL);
return _g_module_build_path (directory, module_name);
}