gmodule/gmodule.c - third_party/glib - Git at Google

 /* 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 Library 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
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library 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 1997-1999.  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	"gmodule.h"
 #include	"gmoduleconf.h"
 #include	<errno.h>
 #include	<string.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;
   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);
 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 --- */
 G_LOCK_DEFINE_STATIC (GModule);
 const char           *g_log_domain_gmodule = "GModule";
 static GModule	     *modules = NULL;
 static GModule	     *main_module = NULL;
 static GStaticPrivate module_error_private = G_STATIC_PRIVATE_INIT;


 /* --- inline functions --- */
 static inline GModule*
 g_module_find_by_handle (gpointer handle)
 {
   GModule *module;
   GModule *retval = NULL;

   G_LOCK (GModule);
   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;
 	}
   G_UNLOCK (GModule);

   return retval;
 }

 static inline GModule*
 g_module_find_by_name (const gchar *name)
 {
   GModule *module;
   GModule *retval = NULL;

   G_LOCK (GModule);
   for (module = modules; module; module = module->next)
     if (strcmp (name, module->file_name) == 0)
 	{
 	  retval = module;
 	  break;
 	}
   G_UNLOCK (GModule);

   return retval;
 }

 static inline void
 g_module_set_error (const gchar *error)
 {
   g_static_private_set (&module_error_private, g_strdup (error), g_free);
   errno = 0;
 }


 /* --- include platform specifc code --- */
 #define	CHECK_ERROR(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"
 #else
 #undef	CHECK_ERROR
 #define	CHECK_ERROR(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)
 {
   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 */

 #if defined (NATIVE_WIN32) && defined (__LCC__)
 int __stdcall
 LibMain (void         *hinstDll,
 	 unsigned long dwReason,
 	 void         *reserved)
 {
   return 1;
 }
 #endif /* NATIVE_WIN32 && __LCC__ */


 /* --- functions --- */
 gboolean
 g_module_supported (void)
 {
   CHECK_ERROR (FALSE);

   return TRUE;
 }

 GModule*
 g_module_open (const gchar    *file_name,
 	       GModuleFlags    flags)
 {
   GModule *module;
   gpointer handle;

   CHECK_ERROR (NULL);

   if (!file_name)
     {
       G_LOCK (GModule);
       if (!main_module)
 	{
 	  handle = _g_module_self ();
 	  if (handle)
 	    {
 	      main_module = g_new (GModule, 1);
 	      main_module->file_name = NULL;
 	      main_module->handle = handle;
 	      main_module->ref_count = 1;
 	      main_module->is_resident = TRUE;
 	      main_module->unload = NULL;
 	      main_module->next = NULL;
 	    }
 	}
       G_UNLOCK (GModule);

       return main_module;
     }

   /* we first search the module list by name */
   module = g_module_find_by_name (file_name);
   if (module)
     {
       module->ref_count++;

       return module;
     }

   /* open the module */
   handle = _g_module_open (file_name, (flags & G_MODULE_BIND_LAZY) != 0);
   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);

 	  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);
       module->handle = handle;
       module->ref_count = 1;
       module->is_resident = FALSE;
       module->unload = NULL;
       G_LOCK (GModule);
       module->next = modules;
       modules = module;
       G_UNLOCK (GModule);

       /* check initialization */
       if (g_module_symbol (module, "g_module_check_init", (gpointer) &check_init))
 	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 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);
     }

   return module;
 }

 gboolean
 g_module_close (GModule	       *module)
 {
   CHECK_ERROR (FALSE);

   g_return_val_if_fail (module != NULL, FALSE);
   g_return_val_if_fail (module->ref_count > 0, FALSE);

   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;

       G_LOCK (GModule);
       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_UNLOCK (GModule);

       _g_module_close (module->handle, FALSE);
       g_free (module->file_name);

       g_free (module);
     }

   return g_module_error() == NULL;
 }

 void
 g_module_make_resident (GModule *module)
 {
   g_return_if_fail (module != NULL);

   module->is_resident = TRUE;
 }

 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)
 {
   gchar *module_error;
   if (symbol)
     *symbol = NULL;
   CHECK_ERROR (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);

 #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 */

   if ((module_error = g_module_error()))
     {
       gchar *error;

       error = g_strconcat ("`", symbol_name, "': ", module_error, NULL);
       g_module_set_error (error);
       g_free (error);
       *symbol = NULL;
       return FALSE;
     }

   return TRUE;
 }

 gchar*
 g_module_name (GModule *module)
 {
   g_return_val_if_fail (module != NULL, NULL);

   if (module == main_module)
     return "main";

   return module->file_name;
 }

 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);
 }
	/* 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 Library 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
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library 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 1997-1999. 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 "gmodule.h"
	#include "gmoduleconf.h"
	#include <errno.h>
	#include <string.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;
	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);
	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 --- */
	G_LOCK_DEFINE_STATIC (GModule);
	const char *g_log_domain_gmodule = "GModule";
	static GModule *modules = NULL;
	static GModule *main_module = NULL;
	static GStaticPrivate module_error_private = G_STATIC_PRIVATE_INIT;


	/* --- inline functions --- */
	static inline GModule*
	g_module_find_by_handle (gpointer handle)
	{
	GModule *module;
	GModule *retval = NULL;

	G_LOCK (GModule);
	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;
	}
	G_UNLOCK (GModule);

	return retval;
	}

	static inline GModule*
	g_module_find_by_name (const gchar *name)
	{
	GModule *module;
	GModule *retval = NULL;

	G_LOCK (GModule);
	for (module = modules; module; module = module->next)
	if (strcmp (name, module->file_name) == 0)
	{
	retval = module;
	break;
	}
	G_UNLOCK (GModule);

	return retval;
	}

	static inline void
	g_module_set_error (const gchar *error)
	{
	g_static_private_set (&module_error_private, g_strdup (error), g_free);
	errno = 0;
	}


	/* --- include platform specifc code --- */
	#define CHECK_ERROR(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"
	#else
	#undef CHECK_ERROR
	#define CHECK_ERROR(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)
	{
	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 */

	#if defined (NATIVE_WIN32) && defined (__LCC__)
	int __stdcall
	LibMain (void *hinstDll,
	unsigned long dwReason,
	void *reserved)
	{
	return 1;
	}
	#endif /* NATIVE_WIN32 && __LCC__ */


	/* --- functions --- */
	gboolean
	g_module_supported (void)
	{
	CHECK_ERROR (FALSE);

	return TRUE;
	}

	GModule*
	g_module_open (const gchar *file_name,
	GModuleFlags flags)
	{
	GModule *module;
	gpointer handle;

	CHECK_ERROR (NULL);

	if (!file_name)
	{
	G_LOCK (GModule);
	if (!main_module)
	{
	handle = _g_module_self ();
	if (handle)
	{
	main_module = g_new (GModule, 1);
	main_module->file_name = NULL;
	main_module->handle = handle;
	main_module->ref_count = 1;
	main_module->is_resident = TRUE;
	main_module->unload = NULL;
	main_module->next = NULL;
	}
	}
	G_UNLOCK (GModule);

	return main_module;
	}

	/* we first search the module list by name */
	module = g_module_find_by_name (file_name);
	if (module)
	{
	module->ref_count++;

	return module;
	}

	/* open the module */
	handle = _g_module_open (file_name, (flags & G_MODULE_BIND_LAZY) != 0);
	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);

	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);
	module->handle = handle;
	module->ref_count = 1;
	module->is_resident = FALSE;
	module->unload = NULL;
	G_LOCK (GModule);
	module->next = modules;
	modules = module;
	G_UNLOCK (GModule);

	/* check initialization */
	if (g_module_symbol (module, "g_module_check_init", (gpointer) &check_init))
	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 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);
	}

	return module;
	}

	gboolean
	g_module_close (GModule *module)
	{
	CHECK_ERROR (FALSE);

	g_return_val_if_fail (module != NULL, FALSE);
	g_return_val_if_fail (module->ref_count > 0, FALSE);

	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;

	G_LOCK (GModule);
	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_UNLOCK (GModule);

	_g_module_close (module->handle, FALSE);
	g_free (module->file_name);

	g_free (module);
	}

	return g_module_error() == NULL;
	}

	void
	g_module_make_resident (GModule *module)
	{
	g_return_if_fail (module != NULL);

	module->is_resident = TRUE;
	}

	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)
	{
	gchar *module_error;
	if (symbol)
	*symbol = NULL;
	CHECK_ERROR (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);

	#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 */

	if ((module_error = g_module_error()))
	{
	gchar *error;

	error = g_strconcat ("`", symbol_name, "': ", module_error, NULL);
	g_module_set_error (error);
	g_free (error);
	*symbol = NULL;
	return FALSE;
	}

	return TRUE;
	}

	gchar*
	g_module_name (GModule *module)
	{
	g_return_val_if_fail (module != NULL, NULL);

	if (module == main_module)
	return "main";

	return module->file_name;
	}

	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);
	}