/* GMODULE - GLIB wrapper code for dynamic module loading

 * Copyright (C) 1998 Tim Janik

 * Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 *

 * 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

 */

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include	"gstdio.h"

#include	"gmodule.h"

#include	"gmoduleconf.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

#if defined (G_OS_WIN32)

# include <io.h>		/* For open() and close() prototypes. */

#endif

#ifdef __SYMBIAN32__

#include <gmodule_wsd.h>

#endif /* __SYMBIAN32__ */

/* 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;

#ifdef G_OS_WIN32

  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 --- */

#if EMULATOR

PLS(modules,gmodule,GModule *)

PLS(main_module,gmodule,GModule *)

PLS(module_error_private,gmodule,GStaticPrivate)

#define modules (*FUNCTION_NAME(modules,gmodule)())

#define main_module (*FUNCTION_NAME(main_module,gmodule)())

#define module_error_private (*FUNCTION_NAME(module_error_private,gmodule)())

#else

static GModule	     *modules = NULL;

static GModule	     *main_module = NULL;

static GStaticPrivate module_error_private = G_STATIC_PRIVATE_INIT;

#endif /* EMULATOR */

/* --- 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 --- */

EXPORT_C 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;

}

#if EMULATOR

PLS(g_module_global_lock,gmodule,GStaticRecMutex)

#define g_module_global_lock (*FUNCTION_NAME(g_module_global_lock,gmodule)())

#else

static GStaticRecMutex g_module_global_lock = G_STATIC_REC_MUTEX_INIT;

#endif /* EMULATOR */

EXPORT_C 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 (!file_name)

    {      

      if (!main_module)

	{

	  handle = _g_module_self ();

	  if (handle)

	    {

	      main_module = g_new (GModule, 1);

	      main_module->file_name = NULL;

#ifdef G_OS_WIN32

	      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 */

	  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);

#ifdef G_OS_WIN32

      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_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);

    }

  g_static_rec_mutex_unlock (&g_module_global_lock);

  return module;

}

#ifdef G_OS_WIN32

#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

EXPORT_C 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--;