/* GMODULE - GLIB wrapper code for dynamic module loading

 * Copyright (C) 1998 Tim Janik

 *

 * SPDX-License-Identifier: LGPL-2.1-or-later

 *

 * 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 "glib.h"

#include "gmodule.h"

#include <errno.h>

#include <string.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#ifdef G_OS_UNIX

#include <unistd.h>

#endif

#ifdef G_OS_WIN32

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

#endif

#ifndef O_CLOEXEC

#define O_CLOEXEC 0

#endif

#include "gmoduleconf.h"

#include "gstdio.h"

/**

 * SECTION:modules

 * @title: Dynamic Loading of Modules

 * @short_description: portable method for dynamically loading 'plug-ins'

 *

 * These functions provide a portable way to dynamically load object files

 * (commonly known as 'plug-ins'). The current implementation supports all

 * systems that provide an implementation of dlopen() (e.g. Linux/Sun), as

 * well as Windows platforms via DLLs.

 *

 * A program which wants to use these functions must be linked to the

 * libraries output by the command `pkg-config --libs gmodule-2.0`.

 *

 * To use them you must first determine whether dynamic loading

 * is supported on the platform by calling g_module_supported().

 * If it is, you can open a module with g_module_open(),

 * find the module's symbols (e.g. function names) with g_module_symbol(),

 * and later close the module with g_module_close().

 * g_module_name() will return the file name of a currently opened module.

 *

 * If any of the above functions fail, the error status can be found with

 * g_module_error().

 *

 * The #GModule implementation features reference counting for opened modules,

 * and supports hook functions within a module which are called when the

 * module is loaded and unloaded (see #GModuleCheckInit and #GModuleUnload).

 *

 * If your module introduces static data to common subsystems in the running

 * program, e.g. through calling

 * `g_quark_from_static_string ("my-module-stuff")`,

 * it must ensure that it is never unloaded, by calling g_module_make_resident().

 *

 * Example: Calling a function defined in a GModule

 * |[<!-- language="C" --> 

 * // the function signature for 'say_hello'

 * typedef void (* SayHelloFunc) (const char *message);

 *

 * gboolean

 * just_say_hello (const char *filename, GError **error)

 * {

 *   SayHelloFunc  say_hello;

 *   GModule      *module;

 *

 *   module = g_module_open (filename, G_MODULE_BIND_LAZY);

 *   if (!module)

 *     {

 *       g_set_error (error, FOO_ERROR, FOO_ERROR_BLAH,

 *                    "%s", g_module_error ());

 *       return FALSE;

 *     }

 *

 *   if (!g_module_symbol (module, "say_hello", (gpointer *)&say_hello))

 *     {

 *       g_set_error (error, SAY_ERROR, SAY_ERROR_OPEN,

 *                    "%s: %s", filename, g_module_error ());

 *       if (!g_module_close (module))

 *         g_warning ("%s: %s", filename, g_module_error ());

 *       return FALSE;

 *     }

 *

 *   if (say_hello == NULL)

 *     {

 *       g_set_error (error, SAY_ERROR, SAY_ERROR_OPEN,

 *                    "symbol say_hello is NULL");

 *       if (!g_module_close (module))

 *         g_warning ("%s: %s", filename, g_module_error ());

 *       return FALSE;

 *     }

 *

 *   // call our function in the module

 *   say_hello ("Hello world!");

 *

 *   if (!g_module_close (module))

 *     g_warning ("%s: %s", filename, g_module_error ());

 *   return TRUE;

 *  }

 * ]|

 */

/**

 * GModule:

 *

 * The #GModule struct is an opaque data structure to represent a

 * [dynamically-loaded module][glib-Dynamic-Loading-of-Modules].

 * It should only be accessed via the following functions.

 */

/**

 * GModuleCheckInit:

 * @module: the #GModule corresponding to the module which has just been loaded

 *

 * Specifies the type of the module initialization function.

 * If a module contains a function named g_module_check_init() it is called

 * automatically when the module is loaded. It is passed the #GModule structure

 * and should return %NULL on success or a string describing the initialization

 * error.

 *

 * Returns: %NULL on success, or a string describing the initialization error

 */

/**

 * GModuleUnload:

 * @module: the #GModule about to be unloaded

 *

 * Specifies the type of the module function called when it is unloaded.

 * If a module contains a function named g_module_unload() it is called

 * automatically when the module is unloaded.

 * It is passed the #GModule structure.

 */

/**

 * G_MODULE_SUFFIX:

 *

 * Expands to a shared library suffix for the current platform without the

 * leading dot. On Unixes this is "so", and on Windows this is "dll".

 *

 * Deprecated: 2.76: Use g_module_open() instead with @module_name as the

 * basename of the file_name argument. You will get the wrong results using

 * this macro most of the time:

 *

 * 1. The suffix on macOS is usually 'dylib', but it's 'so' when using

 *    Autotools, so there's no way to get the suffix correct using

 *    a pre-processor macro.

 * 2. Prefixes also vary in a platform-specific way. You may or may not have

 *    a 'lib' prefix for the name on Windows and on Cygwin the prefix is

 *    'cyg'.

 * 3. The library name itself can vary per platform. For instance, you may

 *    want to load foo-1.dll on Windows and libfoo.1.dylib on macOS.

 *

 * g_module_open() takes care of all this by searching the filesystem for

 * combinations of possible suffixes and prefixes.

 */

/**

 * G_MODULE_EXPORT:

 *

 * Used to declare functions exported by libraries or modules.

 *

 * When compiling for Windows, it marks the symbol as `dllexport`.

 *

 * When compiling for Linux and Unices, it marks the symbol as having `default`

 * visibility. This is no-op unless the code is being compiled with a

 * non-default

 * [visibility flag](https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#index-fvisibility-1260)

 * such as `hidden`.

 *

 * This macro must only be used when compiling a shared module. Modules that

 * support both shared and static linking should define their own macro that

 * expands to %G_MODULE_EXPORT when compiling the shared module, but is empty

 * when compiling the static module on Windows.

 */

/**

 * G_MODULE_IMPORT:

 *

 * Used to declare functions imported from modules.

 */

/* We maintain a list of modules, so we can reference count them.

 * That's needed because some platforms don't support references counts on

 * modules. Also, the module for the program itself is kept separately 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,

                                gboolean      bind_local,

                                GError      **error);

static void   _g_module_close   (gpointer  handle);

static gpointer   _g_module_self    (void);

static gpointer   _g_module_symbol  (gpointer  handle,

             const gchar  *symbol_name);

#if (G_MODULE_IMPL != G_MODULE_IMPL_DL) && (G_MODULE_IMPL != G_MODULE_IMPL_AR)

static gchar*   _g_module_build_path  (const gchar  *directory,

             const gchar  *module_name);

#else

/* Implementation is in gmodule-deprecated.c */

gchar*            _g_module_build_path  (const gchar  *directory,

             const gchar  *module_name);

#endif

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 GPrivate       module_error_private = G_PRIVATE_INIT (g_free);

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_private_replace (&module_error_private, error);

  errno = 0;

}

static inline void

g_module_set_error (const gchar *error)

{

  g_module_set_error_unduped (g_strdup (error));

}

/* --- include platform specific 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_WIN32)

#include "gmodule-win32.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,

                GError      **error)

{

  g_module_set_error (NULL);

  return NULL;

}

static void

_g_module_close (gpointer handle)

{

}

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 */

/**

 * G_MODULE_ERROR:

 *

 * The error domain of the #GModule API.

 *

 * Since: 2.70

 */

G_DEFINE_QUARK (g-module-error-quark, g_module_error)

/* --- functions --- */

/**

 * g_module_supported:

 *

 * Checks if modules are supported on the current platform.

 *

 * Returns: %TRUE if modules are supported

 */

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 | O_CLOEXEC, 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);

    }

  g_clear_pointer (&scanner, g_scanner_destroy);

  close (g_steal_fd (&fd));

  if (lt_libdir == NULL || lt_dlname == NULL)

    {

      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);

      return NULL;

    }

  name = g_strconcat (lt_libdir, G_DIR_SEPARATOR_S, lt_dlname, NULL);

  g_free (lt_dlname);

  g_free (lt_libdir);

  return name;

}

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 GRecMutex g_module_global_lock;

/**

 * g_module_open_full:

 * @file_name: (nullable): the name or path to the file containing the module,

 *     or %NULL to obtain a #GModule representing the main program itself

 * @flags: the flags used for opening the module. This can be the

 *     logical OR of any of the #GModuleFlags

 * @error: #GError.

 *

 * Opens a module. If the module has already been opened, its reference count

 * is incremented. If not, the module is searched in the following order:

 *

 * 1. If @file_name exists as a regular file, it is used as-is; else

 * 2. If @file_name doesn't have the correct suffix and/or prefix for the

 *    platform, then possible suffixes and prefixes will be added to the

 *    basename till a file is found and whatever is found will be used; else

 * 3. If @file_name doesn't have the ".la"-suffix, ".la" is appended. Either

 *    way, if a matching .la file exists (and is a libtool archive) the

 *    libtool archive is parsed to find the actual file name, and that is

 *    used.

 *

 * At the end of all this, we would have a file path that we can access on

 * disk, and it is opened as a module. If not, @file_name is opened as

 * a module verbatim in the hopes that the system implementation will somehow

 * be able to access it.

 *

 * Returns: a #GModule on success, or %NULL on failure

 *

 * Since: 2.70

 */

GModule*

g_module_open_full (const gchar   *file_name,

                    GModuleFlags   flags,

                    GError       **error)

{

  GModule *module;

  gpointer handle = NULL;

  gchar *name = NULL;

  SUPPORT_OR_RETURN (NULL);

  g_return_val_if_fail (error == NULL || *error == NULL, NULL);

  g_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 ();

/* On Android 64 bit, RTLD_DEFAULT is (void *)0x0

 * so it always fails to create main_module if file_name is NULL */

#if !defined(__BIONIC__) || !defined(__LP64__)

    if (handle)

#endif

      {

        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;

      }

  }

      else

  main_module->ref_count++;

      g_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_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)

    {

      char *basename, *dirname;

      size_t prefix_idx = 0, suffix_idx = 0;

      const char *prefixes[2] = {0}, *suffixes[2] = {0};

      basename = g_path_get_basename (file_name);

      dirname = g_path_get_dirname (file_name);

#ifdef G_OS_WIN32

      if (!g_str_has_prefix (basename, "lib"))

        prefixes[prefix_idx++] = "lib";

      prefixes[prefix_idx++] = "";

      if (!g_str_has_suffix (basename, ".dll"))

        suffixes[suffix_idx++] = ".dll";

#else

  #ifdef __CYGWIN__

      if (!g_str_has_prefix (basename, "cyg"))

        prefixes[prefix_idx++] = "cyg";

  #else

      if (!g_str_has_prefix (basename, "lib"))

        prefixes[prefix_idx++] = "lib";

      else

        /* People commonly pass `libfoo` as the file_name and want us to

         * auto-detect the suffix as .la or .so, etc. We need to also find

         * .dylib and .dll in those cases. */

        prefixes[prefix_idx++] = "";

  #endif

  #ifdef __APPLE__

      if (!g_str_has_suffix (basename, ".dylib") &&

          !g_str_has_suffix (basename, ".so"))

        {

          suffixes[suffix_idx++] = ".dylib";

          suffixes[suffix_idx++] = ".so";

        }

  #else

      if (!g_str_has_suffix (basename, ".so"))

        suffixes[suffix_idx++] = ".so";

  #endif

#endif

      for (guint i = 0; i < prefix_idx; i++)

        {

          for (guint j = 0; j < suffix_idx; j++)

            {

              name = g_strconcat (dirname, G_DIR_SEPARATOR_S, prefixes[i],

                                  basename, suffixes[j], NULL);

              if (g_file_test (name, G_FILE_TEST_IS_REGULAR))

                goto name_found;

              g_free (name);

              name = NULL;

            }

        }

    name_found:

      g_free (basename);

      g_free (dirname);

    }

  /* 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);

      /* we make sure the name has a suffix using the deprecated

       * G_MODULE_SUFFIX for backward-compat */

      if (!dot || dot < slash)

  name = g_strconcat (file_name, "." G_MODULE_SUFFIX, NULL);

      else

  name = g_strdup (file_name);

    }

  /* ok, try loading the module */

  g_assert (name != NULL);

  /* if it's a libtool archive, figure library file to load */

  if (g_str_has_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;

        }

    }

  handle = _g_module_open (name, (flags & G_MODULE_BIND_LAZY) != 0,

                           (flags & G_MODULE_BIND_LOCAL) != 0, error);

  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);

    module->ref_count++;

    g_module_set_error (NULL);

    g_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);

      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 *temp_error;

          temp_error = g_strconcat ("GModule (", file_name, ") ",

                                    "initialization check failed: ",

                                    check_failed, NULL);

    g_module_close (module);

    module = NULL;

          g_module_set_error (temp_error);

          g_set_error_literal (error, G_MODULE_ERROR, G_MODULE_ERROR_CHECK_FAILED, temp_error);

          g_free (temp_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_rec_mutex_unlock (&g_module_global_lock);

  return module;

}

/**

 * g_module_open:

 * @file_name: (nullable): the name or path to the file containing the module,

 *     or %NULL to obtain a #GModule representing the main program itself

 * @flags: the flags used for opening the module. This can be the

 *     logical OR of any of the #GModuleFlags.

 *

 * A thin wrapper function around g_module_open_full()

 *

 * Returns: a #GModule on success, or %NULL on failure

 */

GModule *

g_module_open (const gchar  *file_name,

               GModuleFlags  flags)

{

  return g_module_open_full (file_name, flags, NULL);

}

/**

 * g_module_close:

 * @module: a #GModule to close

 *

 * Closes a module.

 *

 * Returns: %TRUE on success

 */

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_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);

      g_free (module->file_name);

      g_free (module);

    }

  g_rec_mutex_unlock (&g_module_global_lock);

  return g_module_error() == NULL;

}

/**

 * g_module_make_resident:

 * @module: a #GModule to make permanently resident

 *

 * Ensures that a module will never be unloaded.

 * Any future g_module_close() calls on the module will be ignored.

 */

void

g_module_make_resident (GModule *module)

{

  g_return_if_fail (module != NULL);

  module->is_resident = TRUE;

}

/**

 * g_module_error:

 *

 * Gets a string describing the last module error.

 *

 * Returns: a string describing the last module error

 */

const gchar *

g_module_error (void)

{

  return g_private_get (&module_error_private);

}

/**

 * g_module_symbol:

 * @module: a #GModule

 * @symbol_name: the name of the symbol to find

 * @symbol: (out): returns the pointer to the symbol value

 *

 * Gets a symbol pointer from a module, such as one exported

 * by %G_MODULE_EXPORT. Note that a valid symbol can be %NULL.

 *

 * Returns: %TRUE on success

 */

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_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_rec_mutex_unlock (&g_module_global_lock);

  return !module_error;

}

/**

 * g_module_name:

 * @module: a #GModule

 *

 * Returns the filename that the module was opened with.

 *

 * If @module refers to the application itself, "main" is returned.

 *

 * Returns: (transfer none): the filename of the module

 */

const gchar *

g_module_name (GModule *module)

{

  g_return_val_if_fail (module != NULL, NULL);

  if (module == main_module)

    return "main";

  return module->file_name;

}

/**

 * g_module_build_path:

 * @directory: (nullable): the directory where the module is. This can be

 *     %NULL or the empty string to indicate that the standard platform-specific

 *     directories will be used, though that is not recommended

 * @module_name: the name of the module

 *

 * A portable way to build the filename of a module. The platform-specific

 * prefix and suffix are added to the filename, if needed, and the result

 * is added to the directory, using the correct separator character.

 *

 * The directory should specify the directory where the module can be found.

 * It can be %NULL or an empty string to indicate that the module is in a

 * standard platform-specific directory, though this is not recommended

 * since the wrong module may be found.

 *

 * For example, calling g_module_build_path() on a Linux system with a

 * @directory of `/lib` and a @module_name of "mylibrary" will return

 * `/lib/libmylibrary.so`. On a Windows system, using `\Windows` as the

 * directory it will return `\Windows\mylibrary.dll`.

 *

 * Returns: the complete path of the module, including the standard library

 *     prefix and suffix. This should be freed when no longer needed

 *

 * Deprecated: 2.76: Use g_module_open() instead with @module_name as the

 * basename of the file_name argument. See %G_MODULE_SUFFIX for why.

 */

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);

}