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glib/gio/giomodule.c

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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright (C) 2006-2007 Red Hat, Inc.
*
* 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/>.
*
* Author: Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
/* For the #GDesktopAppInfoLookup macros; since macro deprecation is implemented
* in the preprocessor, we need to define this before including glib.h*/
#ifndef GLIB_DISABLE_DEPRECATION_WARNINGS
#define GLIB_DISABLE_DEPRECATION_WARNINGS
#endif
#include <string.h>
#include "giomodule.h"
#include "giomodule-priv.h"
#include "glib-private.h"
#include "glocalfilemonitor.h"
#include "gnativevolumemonitor.h"
#include "gproxyresolver.h"
#include "gproxy.h"
#include "gsettingsbackendinternal.h"
#include "ghttpproxy.h"
#include "gsocks4proxy.h"
#include "gsocks4aproxy.h"
#include "gsocks5proxy.h"
#include "gtlsbackend.h"
#include "gvfs.h"
#include "gnotificationbackend.h"
#include "ginitable.h"
#include "gnetworkmonitor.h"
#include "gdebugcontroller.h"
#include "gdebugcontrollerdbus.h"
#include "gmemorymonitor.h"
#include "gmemorymonitorportal.h"
#include "gmemorymonitordbus.h"
#include "gpowerprofilemonitor.h"
#include "gpowerprofilemonitordbus.h"
#include "gpowerprofilemonitorportal.h"
#ifdef G_OS_WIN32
#include "gregistrysettingsbackend.h"
#include "giowin32-priv.h"
#endif
#include <glib/gstdio.h>
#if defined(G_OS_UNIX) && !defined(__APPLE__)
#include "gdesktopappinfo.h"
#endif
#ifdef HAVE_COCOA
#include "gosxappinfo.h"
#endif
#ifdef __APPLE__
#include <AvailabilityMacros.h>
#endif
#define __GLIB_H_INSIDE__
#include "gconstructor.h"
#undef __GLIB_H_INSIDE__
/**
* GIOModule:
*
* Provides an interface and default functions for loading and unloading
* modules. This is used internally to make GIO extensible, but can also
* be used by others to implement module loading.
*/
/**
* GIOExtensionPoint:
*
* `GIOExtensionPoint` provides a mechanism for modules to extend the
* functionality of the library or application that loaded it in an
* organized fashion.
*
* An extension point is identified by a name, and it may optionally
* require that any implementation must be of a certain type (or derived
* thereof). Use [func@Gio.IOExtensionPoint.register] to register an
* extension point, and [method@Gio.IOExtensionPoint.set_required_type] to
* set a required type.
*
* A module can implement an extension point by specifying the
* [type@GObject.Type] that implements the functionality. Additionally, each
* implementation of an extension point has a name, and a priority. Use
* [func@Gio.IOExtensionPoint.implement] to implement an extension point.
*
* ```c
* GIOExtensionPoint *ep;
*
* // Register an extension point
* ep = g_io_extension_point_register ("my-extension-point");
* g_io_extension_point_set_required_type (ep, MY_TYPE_EXAMPLE);
* ```
*
* ```c
* // Implement an extension point
* G_DEFINE_TYPE (MyExampleImpl, my_example_impl, MY_TYPE_EXAMPLE)
* g_io_extension_point_implement ("my-extension-point",
* my_example_impl_get_type (),
* "my-example",
* 10);
* ```
*
* It is up to the code that registered the extension point how
* it uses the implementations that have been associated with it.
* Depending on the use case, it may use all implementations, or
* only the one with the highest priority, or pick a specific
* one by name.
*
* To avoid opening all modules just to find out what extension
* points they implement, GIO makes use of a caching mechanism,
* see [gio-querymodules](gio-querymodules.html).
* You are expected to run this command after installing a
* GIO module.
*
* The `GIO_EXTRA_MODULES` environment variable can be used to
* specify additional directories to automatically load modules
* from. This environment variable has the same syntax as the
* `PATH`. If two modules have the same base name in different
* directories, then the latter one will be ignored. If additional
* directories are specified GIO will load modules from the built-in
* directory last.
*/
/**
* GIOModuleScope:
*
* Represents a scope for loading IO modules. A scope can be used for blocking
* duplicate modules, or blocking a module you don't want to load.
*
* The scope can be used with g_io_modules_load_all_in_directory_with_scope()
* or g_io_modules_scan_all_in_directory_with_scope().
*
* Since: 2.30
*/
struct _GIOModuleScope {
GIOModuleScopeFlags flags;
GHashTable *basenames;
};
/**
* g_io_module_scope_new:
* @flags: flags for the new scope
*
* Create a new scope for loading of IO modules. A scope can be used for
* blocking duplicate modules, or blocking a module you don't want to load.
*
* Specify the %G_IO_MODULE_SCOPE_BLOCK_DUPLICATES flag to block modules
* which have the same base name as a module that has already been seen
* in this scope.
*
* Returns: (transfer full): the new module scope
*
* Since: 2.30
*/
GIOModuleScope *
g_io_module_scope_new (GIOModuleScopeFlags flags)
{
GIOModuleScope *scope = g_new0 (GIOModuleScope, 1);
scope->flags = flags;
scope->basenames = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
return scope;
}
/**
* g_io_module_scope_free:
* @scope: a module loading scope
*
* Free a module scope.
*
* Since: 2.30
*/
void
g_io_module_scope_free (GIOModuleScope *scope)
{
if (!scope)
return;
g_hash_table_destroy (scope->basenames);
g_free (scope);
}
/**
* g_io_module_scope_block:
* @scope: a module loading scope
* @basename: the basename to block
*
* Block modules with the given @basename from being loaded when
* this scope is used with g_io_modules_scan_all_in_directory_with_scope()
* or g_io_modules_load_all_in_directory_with_scope().
*
* Since: 2.30
*/
void
g_io_module_scope_block (GIOModuleScope *scope,
const gchar *basename)
{
gchar *key;
g_return_if_fail (scope != NULL);
g_return_if_fail (basename != NULL);
key = g_strdup (basename);
g_hash_table_add (scope->basenames, key);
}
static gboolean
_g_io_module_scope_contains (GIOModuleScope *scope,
const gchar *basename)
{
return g_hash_table_contains (scope->basenames, basename);
}
struct _GIOModule {
GTypeModule parent_instance;
gchar *filename;
GModule *library;
gboolean initialized; /* The module was loaded at least once */
void (* load) (GIOModule *module);
void (* unload) (GIOModule *module);
};
struct _GIOModuleClass
{
GTypeModuleClass parent_class;
};
static void g_io_module_finalize (GObject *object);
static gboolean g_io_module_load_module (GTypeModule *gmodule);
static void g_io_module_unload_module (GTypeModule *gmodule);
/**
* GIOExtension:
*
* #GIOExtension is an opaque data structure and can only be accessed
* using the following functions.
*/
struct _GIOExtension {
char *name;
GType type;
gint priority;
};
struct _GIOExtensionPoint {
GType required_type;
char *name;
GList *extensions;
GList *lazy_load_modules;
};
static GHashTable *extension_points = NULL;
G_LOCK_DEFINE_STATIC(extension_points);
G_DEFINE_TYPE (GIOModule, g_io_module, G_TYPE_TYPE_MODULE)
static void
g_io_module_class_init (GIOModuleClass *class)
{
GObjectClass *object_class = G_OBJECT_CLASS (class);
GTypeModuleClass *type_module_class = G_TYPE_MODULE_CLASS (class);
object_class->finalize = g_io_module_finalize;
type_module_class->load = g_io_module_load_module;
type_module_class->unload = g_io_module_unload_module;
}
static void
g_io_module_init (GIOModule *module)
{
}
static void
g_io_module_finalize (GObject *object)
{
GIOModule *module = G_IO_MODULE (object);
g_free (module->filename);
G_OBJECT_CLASS (g_io_module_parent_class)->finalize (object);
}
static gboolean
load_symbols (GIOModule *module)
{
gchar *name;
gchar *load_symname;
gchar *unload_symname;
gboolean ret;
name = _g_io_module_extract_name (module->filename);
load_symname = g_strconcat ("g_io_", name, "_load", NULL);
unload_symname = g_strconcat ("g_io_", name, "_unload", NULL);
ret = g_module_symbol (module->library,
load_symname,
(gpointer) &module->load) &&
g_module_symbol (module->library,
unload_symname,
(gpointer) &module->unload);
if (!ret)
{
/* Fallback to old names */
ret = g_module_symbol (module->library,
"g_io_module_load",
(gpointer) &module->load) &&
g_module_symbol (module->library,
"g_io_module_unload",
(gpointer) &module->unload);
}
g_free (name);
g_free (load_symname);
g_free (unload_symname);
return ret;
}
static gboolean
g_io_module_load_module (GTypeModule *gmodule)
{
GIOModule *module = G_IO_MODULE (gmodule);
GError *error = NULL;
if (!module->filename)
{
g_warning ("GIOModule path not set");
return FALSE;
}
module->library = g_module_open_full (module->filename, G_MODULE_BIND_LAZY | G_MODULE_BIND_LOCAL, &error);
if (!module->library)
{
g_printerr ("%s\n", error->message);
g_clear_error (&error);
return FALSE;
}
/* Make sure that the loaded library contains the required methods */
if (!load_symbols (module))
{
g_printerr ("%s\n", g_module_error ());
g_module_close (module->library);
return FALSE;
}
/* Initialize the loaded module */
module->load (module);
module->initialized = TRUE;
return TRUE;
}
static void
g_io_module_unload_module (GTypeModule *gmodule)
{
GIOModule *module = G_IO_MODULE (gmodule);
module->unload (module);
g_module_close (module->library);
module->library = NULL;
module->load = NULL;
module->unload = NULL;
}
/**
* g_io_module_new:
* @filename: (type filename): filename of the shared library module.
*
* Creates a new GIOModule that will load the specific
* shared library when in use.
*
* Returns: a #GIOModule from given @filename,
* or %NULL on error.
**/
GIOModule *
g_io_module_new (const gchar *filename)
{
GIOModule *module;
g_return_val_if_fail (filename != NULL, NULL);
module = g_object_new (G_IO_TYPE_MODULE, NULL);
module->filename = g_strdup (filename);
return module;
}
static gboolean
is_valid_module_name (const gchar *basename,
GIOModuleScope *scope)
{
gboolean result;
#if !defined(G_OS_WIN32) && !defined(G_WITH_CYGWIN)
#if defined(__APPLE__)
if (!g_str_has_prefix (basename, "lib") ||
!(g_str_has_suffix (basename, ".so") ||
g_str_has_suffix (basename, ".dylib")))
return FALSE;
#else
if (!g_str_has_prefix (basename, "lib") ||
!g_str_has_suffix (basename, ".so"))
return FALSE;
#endif
#else
if (!g_str_has_suffix (basename, ".dll"))
return FALSE;
#endif
result = TRUE;
if (scope)
{
result = _g_io_module_scope_contains (scope, basename) ? FALSE : TRUE;
if (result && (scope->flags & G_IO_MODULE_SCOPE_BLOCK_DUPLICATES))
g_io_module_scope_block (scope, basename);
}
return result;
}
/**
* g_io_modules_scan_all_in_directory_with_scope:
* @dirname: (type filename): pathname for a directory containing modules
* to scan.
* @scope: a scope to use when scanning the modules
*
* Scans all the modules in the specified directory, ensuring that
* any extension point implemented by a module is registered.
*
* This may not actually load and initialize all the types in each
* module, some modules may be lazily loaded and initialized when
* an extension point it implements is used with e.g.
* g_io_extension_point_get_extensions() or
* g_io_extension_point_get_extension_by_name().
*
* If you need to guarantee that all types are loaded in all the modules,
* use g_io_modules_load_all_in_directory().
*
* Since: 2.30
**/
void
g_io_modules_scan_all_in_directory_with_scope (const char *dirname,
GIOModuleScope *scope)
{
const gchar *name;
char *filename;
GDir *dir;
GStatBuf statbuf;
char *data;
time_t cache_time;
GHashTable *cache;
if (!g_module_supported ())
return;
dir = g_dir_open (dirname, 0, NULL);
if (!dir)
return;
filename = g_build_filename (dirname, "giomodule.cache", NULL);
cache = NULL;
cache_time = 0;
if (g_stat (filename, &statbuf) == 0 &&
g_file_get_contents (filename, &data, NULL, NULL))
{
char **lines;
int i;
/* cache_time is the time the cache file was created; we also take
* into account the change time because in ostree based systems, all
* system file have mtime equal to epoch 0.
*
* Any file that has a ctime before this was created then and not modified
* since then (userspace can't change ctime). Its possible to change the
* ctime forward without changing the file content, by e.g. chmoding the
* file, but this is uncommon and will only cause us to not use the cache
* so will not cause bugs.
*/
cache_time = MAX(statbuf.st_mtime, statbuf.st_ctime);
lines = g_strsplit (data, "\n", -1);
g_free (data);
for (i = 0; lines[i] != NULL; i++)
{
char *line = lines[i];
char *file;
char *colon;
char **strv_extension_points;
if (line[0] == '#')
continue;
colon = strchr (line, ':');
if (colon == NULL || line == colon)
continue; /* Invalid line, ignore */
*colon = 0; /* terminate filename */
file = g_strdup (line);
colon++; /* after colon */
while (g_ascii_isspace (*colon))
colon++;
if (G_UNLIKELY (!cache))
cache = g_hash_table_new_full (g_str_hash, g_str_equal,
g_free, (GDestroyNotify)g_strfreev);
strv_extension_points = g_strsplit (colon, ",", -1);
g_hash_table_insert (cache, file, strv_extension_points);
}
g_strfreev (lines);
}
while ((name = g_dir_read_name (dir)))
{
if (is_valid_module_name (name, scope))
{
GIOExtensionPoint *extension_point;
GIOModule *module;
gchar *path;
char **strv_extension_points = NULL;
int i;
path = g_build_filename (dirname, name, NULL);
module = g_io_module_new (path);
if (cache)
strv_extension_points = g_hash_table_lookup (cache, name);
if (strv_extension_points != NULL &&
g_stat (path, &statbuf) == 0 &&
statbuf.st_ctime <= cache_time)
{
/* Lazy load/init the library when first required */
for (i = 0; strv_extension_points[i] != NULL; i++)
{
extension_point =
g_io_extension_point_register (strv_extension_points[i]);
extension_point->lazy_load_modules =
g_list_prepend (extension_point->lazy_load_modules,
module);
}
}
else
{
/* Try to load and init types */
if (g_type_module_use (G_TYPE_MODULE (module)))
{
g_type_module_unuse (G_TYPE_MODULE (module)); /* Unload */
/* module must remain alive, because the type system keeps weak refs */
g_ignore_leak (module);
}
else
{
g_printerr ("Failed to load module: %s\n", path);
g_object_unref (module);
}
}
g_free (path);
}
}
g_dir_close (dir);
if (cache)
g_hash_table_destroy (cache);
g_free (filename);
}
/**
* g_io_modules_scan_all_in_directory:
* @dirname: (type filename): pathname for a directory containing modules
* to scan.
*
* Scans all the modules in the specified directory, ensuring that
* any extension point implemented by a module is registered.
*
* This may not actually load and initialize all the types in each
* module, some modules may be lazily loaded and initialized when
* an extension point it implements is used with e.g.
* g_io_extension_point_get_extensions() or
* g_io_extension_point_get_extension_by_name().
*
* If you need to guarantee that all types are loaded in all the modules,
* use g_io_modules_load_all_in_directory().
*
* Since: 2.24
**/
void
g_io_modules_scan_all_in_directory (const char *dirname)
{
g_io_modules_scan_all_in_directory_with_scope (dirname, NULL);
}
/**
* g_io_modules_load_all_in_directory_with_scope:
* @dirname: (type filename): pathname for a directory containing modules
* to load.
* @scope: a scope to use when scanning the modules.
*
* Loads all the modules in the specified directory.
*
* If don't require all modules to be initialized (and thus registering
* all gtypes) then you can use g_io_modules_scan_all_in_directory()
* which allows delayed/lazy loading of modules.
*
* Returns: (element-type GIOModule) (transfer full): a list of #GIOModules loaded
* from the directory,
* All the modules are loaded into memory, if you want to
* unload them (enabling on-demand loading) you must call
* g_type_module_unuse() on all the modules. Free the list
* with g_list_free().
*
* Since: 2.30
**/
GList *
g_io_modules_load_all_in_directory_with_scope (const char *dirname,
GIOModuleScope *scope)
{
const gchar *name;
GDir *dir;
GList *modules;
if (!g_module_supported ())
return NULL;
dir = g_dir_open (dirname, 0, NULL);
if (!dir)
return NULL;
modules = NULL;
while ((name = g_dir_read_name (dir)))
{
if (is_valid_module_name (name, scope))
{
GIOModule *module;
gchar *path;
path = g_build_filename (dirname, name, NULL);
module = g_io_module_new (path);
if (!g_type_module_use (G_TYPE_MODULE (module)))
{
g_printerr ("Failed to load module: %s\n", path);
g_object_unref (module);
g_free (path);
continue;
}
g_free (path);
modules = g_list_prepend (modules, module);
}
}
g_dir_close (dir);
return modules;
}
/**
* g_io_modules_load_all_in_directory:
* @dirname: (type filename): pathname for a directory containing modules
* to load.
*
* Loads all the modules in the specified directory.
*
* If don't require all modules to be initialized (and thus registering
* all gtypes) then you can use g_io_modules_scan_all_in_directory()
* which allows delayed/lazy loading of modules.
*
* Returns: (element-type GIOModule) (transfer full): a list of #GIOModules loaded
* from the directory,
* All the modules are loaded into memory, if you want to
* unload them (enabling on-demand loading) you must call
* g_type_module_unuse() on all the modules. Free the list
* with g_list_free().
**/
GList *
g_io_modules_load_all_in_directory (const char *dirname)
{
return g_io_modules_load_all_in_directory_with_scope (dirname, NULL);
}
static gpointer
try_class (GIOExtension *extension,
guint is_supported_offset)
{
GType type = g_io_extension_get_type (extension);
typedef gboolean (*verify_func) (void);
gpointer class;
class = g_type_class_ref (type);
if (!is_supported_offset || (* G_STRUCT_MEMBER(verify_func, class, is_supported_offset)) ())
return class;
g_type_class_unref (class);
return NULL;
}
static void
print_help (const char *envvar,
GIOExtensionPoint *ep)
{
g_print ("Supported arguments for %s environment variable:\n", envvar);
if (g_io_extension_point_get_extensions (ep) == NULL)
g_print (" (none)\n");
else
{
GList *l;
GIOExtension *extension;
gsize width = 0;
for (l = g_io_extension_point_get_extensions (ep); l; l = l->next)
{
extension = l->data;
width = MAX (width, strlen (g_io_extension_get_name (extension)));
}
for (l = g_io_extension_point_get_extensions (ep); l; l = l->next)
{
extension = l->data;
g_print (" %*s - %d\n", (int) MIN (width, G_MAXINT),
g_io_extension_get_name (extension),
g_io_extension_get_priority (extension));
}
}
}
/**
* _g_io_module_get_default_type:
* @extension_point: the name of an extension point
* @envvar: (nullable): the name of an environment variable to
* override the default implementation.
* @is_supported_offset: a vtable offset, or zero
*
* Retrieves the default class implementing @extension_point.
*
* If @envvar is not %NULL, and the environment variable with that
* name is set, then the implementation it specifies will be tried
* first. After that, or if @envvar is not set, all other
* implementations will be tried in order of decreasing priority.
*
* If @is_supported_offset is non-zero, then it is the offset into the
* class vtable at which there is a function that takes no arguments and
* returns a boolean. This function will be called on each candidate
* implementation to check if it is actually usable or not.
*
* The result is cached after it is generated the first time, and
* the function is thread-safe.
*
* Returns: (transfer none): the type to instantiate to implement
* @extension_point, or %G_TYPE_INVALID if there are no usable
* implementations.
*/
GType
_g_io_module_get_default_type (const gchar *extension_point,
const gchar *envvar,
guint is_supported_offset)
{
static GRecMutex default_modules_lock;
static GHashTable *default_modules;
const char *use_this;
GList *l;
GIOExtensionPoint *ep;
GIOExtension *extension, *preferred;
gpointer impl;
g_rec_mutex_lock (&default_modules_lock);
if (default_modules)
{
gpointer key;
if (g_hash_table_lookup_extended (default_modules, extension_point, &key, &impl))
{
g_rec_mutex_unlock (&default_modules_lock);
return impl ? G_OBJECT_CLASS_TYPE (impl) : G_TYPE_INVALID;
}
}
else
{
default_modules = g_hash_table_new (g_str_hash, g_str_equal);
}
_g_io_modules_ensure_loaded ();
ep = g_io_extension_point_lookup (extension_point);
if (!ep)
{
g_warn_if_reached ();
g_rec_mutex_unlock (&default_modules_lock);
return G_TYPE_INVALID;
}
/* It’s OK to query the environment here, even when running as setuid, because
* it only allows a choice between existing already-loaded modules. No new
* code is loaded based on the environment variable value. */
use_this = envvar ? g_getenv (envvar) : NULL;
if (g_strcmp0 (use_this, "help") == 0)
{
print_help (envvar, ep);
use_this = NULL;
}
if (use_this)
{
preferred = g_io_extension_point_get_extension_by_name (ep, use_this);
if (preferred)
{
impl = try_class (preferred, is_supported_offset);
if (impl)
goto done;
}
else
g_warning ("Can't find module '%s' specified in %s", use_this, envvar);
}
else
preferred = NULL;
for (l = g_io_extension_point_get_extensions (ep); l != NULL; l = l->next)
{
extension = l->data;
if (extension == preferred)
continue;
impl = try_class (extension, is_supported_offset);
if (impl)
goto done;
}
impl = NULL;
done:
g_hash_table_insert (default_modules, g_strdup (extension_point), impl);
g_rec_mutex_unlock (&default_modules_lock);
return impl ? G_OBJECT_CLASS_TYPE (impl) : G_TYPE_INVALID;
}
static gpointer
try_implementation (const char *extension_point,
GIOExtension *extension,
GIOModuleVerifyFunc verify_func)
{
GType type = g_io_extension_get_type (extension);
gpointer impl;
if (g_type_is_a (type, G_TYPE_INITABLE))
{
GError *error = NULL;
impl = g_initable_new (type, NULL, &error, NULL);
if (impl)
return impl;
g_debug ("Failed to initialize %s (%s) for %s: %s",
g_io_extension_get_name (extension),
g_type_name (type),
extension_point,
error ? error->message : "");
g_clear_error (&error);
return NULL;
}
else
{
impl = g_object_new (type, NULL);
if (!verify_func || verify_func (impl))
return impl;
g_object_unref (impl);
return NULL;
}
}
static void
weak_ref_free (GWeakRef *weak_ref)
{
g_weak_ref_clear (weak_ref);
g_free (weak_ref);
}
/**
* _g_io_module_get_default:
* @extension_point: the name of an extension point
* @envvar: (nullable): the name of an environment variable to
* override the default implementation.
* @verify_func: (nullable): a function to call to verify that
* a given implementation is usable in the current environment.
*
* Retrieves the default object implementing @extension_point.
*
* If @envvar is not %NULL, and the environment variable with that
* name is set, then the implementation it specifies will be tried
* first. After that, or if @envvar is not set, all other
* implementations will be tried in order of decreasing priority.
*
* If an extension point implementation implements #GInitable, then
* that implementation will only be used if it initializes
* successfully. Otherwise, if @verify_func is not %NULL, then it will
* be called on each candidate implementation after construction, to
* check if it is actually usable or not.
*
* The result is cached after it is generated the first time (but the cache does
* not keep a strong reference to the object), and
* the function is thread-safe.
*
* Returns: (transfer full) (nullable): an object implementing
* @extension_point, or %NULL if there are no usable
* implementations.
*/
gpointer
_g_io_module_get_default (const gchar *extension_point,
const gchar *envvar,
GIOModuleVerifyFunc verify_func)
{
static GRecMutex default_modules_lock;
static GHashTable *default_modules;
const char *use_this;
GList *l;
GIOExtensionPoint *ep;
GIOExtension *extension = NULL, *preferred;
gpointer impl, value;
GWeakRef *impl_weak_ref = NULL;
g_rec_mutex_lock (&default_modules_lock);
if (default_modules)
{
if (g_hash_table_lookup_extended (default_modules, extension_point,
NULL, &value))
{
/* Don’t debug here, since we’re returning a cached object which was
* already printed earlier. */
impl_weak_ref = value;
impl = g_weak_ref_get (impl_weak_ref);
/* If the object has been finalised (impl == NULL), fall through and
* instantiate a new one. */
if (impl != NULL)
{
g_rec_mutex_unlock (&default_modules_lock);
return g_steal_pointer (&impl);
}
}
}
else
{
default_modules = g_hash_table_new_full (g_str_hash, g_str_equal,
g_free, (GDestroyNotify) weak_ref_free);
}
_g_io_modules_ensure_loaded ();
ep = g_io_extension_point_lookup (extension_point);
if (!ep)
{
g_debug ("%s: Failed to find extension point ‘%s’",
G_STRFUNC, extension_point);
g_warn_if_reached ();
g_rec_mutex_unlock (&default_modules_lock);
return NULL;
}
/* It’s OK to query the environment here, even when running as setuid, because
* it only allows a choice between existing already-loaded modules. No new
* code is loaded based on the environment variable value. */
use_this = envvar ? g_getenv (envvar) : NULL;
if (g_strcmp0 (use_this, "help") == 0)
{
print_help (envvar, ep);
use_this = NULL;
}
if (use_this)
{
preferred = g_io_extension_point_get_extension_by_name (ep, use_this);
if (preferred)
{
impl = try_implementation (extension_point, preferred, verify_func);
extension = preferred;
if (impl)
goto done;
}
else
g_warning ("Can't find module '%s' specified in %s", use_this, envvar);
}
else
preferred = NULL;
for (l = g_io_extension_point_get_extensions (ep); l != NULL; l = l->next)
{
extension = l->data;
if (extension == preferred)
continue;
impl = try_implementation (extension_point, extension, verify_func);
if (impl)
goto done;
}
impl = NULL;
done:
if (impl_weak_ref == NULL)
{
impl_weak_ref = g_new0 (GWeakRef, 1);
g_weak_ref_init (impl_weak_ref, impl);
g_hash_table_insert (default_modules, g_strdup (extension_point),
g_steal_pointer (&impl_weak_ref));
}
else
{
g_weak_ref_set (impl_weak_ref, impl);
}
g_rec_mutex_unlock (&default_modules_lock);
if (impl != NULL)
{
g_assert (extension != NULL);
g_debug ("%s: Found default implementation %s (%s) for ‘%s’",
G_STRFUNC, g_io_extension_get_name (extension),
G_OBJECT_TYPE_NAME (impl), extension_point);
}
else
g_debug ("%s: Failed to find default implementation for ‘%s’",
G_STRFUNC, extension_point);
return g_steal_pointer (&impl);
}
extern GType g_inotify_file_monitor_get_type (void);
extern GType g_kqueue_file_monitor_get_type (void);
extern GType g_win32_file_monitor_get_type (void);
extern GType _g_unix_volume_monitor_get_type (void);
extern GType _g_local_vfs_get_type (void);
extern GType _g_win32_volume_monitor_get_type (void);
extern GType _g_winhttp_vfs_get_type (void);
extern GType _g_dummy_proxy_resolver_get_type (void);
extern GType _g_dummy_tls_backend_get_type (void);
extern GType g_network_monitor_base_get_type (void);
#ifdef HAVE_NETLINK
extern GType _g_network_monitor_netlink_get_type (void);
extern GType _g_network_monitor_nm_get_type (void);
#endif
extern GType g_debug_controller_dbus_get_type (void);
extern GType g_memory_monitor_dbus_get_type (void);
extern GType g_memory_monitor_portal_get_type (void);
extern GType g_memory_monitor_win32_get_type (void);
extern GType g_power_profile_monitor_dbus_get_type (void);
#ifdef G_OS_UNIX
extern GType g_fdo_notification_backend_get_type (void);
extern GType g_gtk_notification_backend_get_type (void);
extern GType g_portal_notification_backend_get_type (void);
extern GType g_proxy_resolver_portal_get_type (void);
extern GType g_network_monitor_portal_get_type (void);
#endif
#if MAC_OS_X_VERSION_MIN_REQUIRED >= 1090
extern GType g_cocoa_notification_backend_get_type (void);
#endif
#ifdef HAVE_COCOA
extern GType g_osx_network_monitor_get_type (void);
#endif
#ifdef G_PLATFORM_WIN32
extern GType g_win32_notification_backend_get_type (void);
#include <windows.h>
extern GType _g_win32_network_monitor_get_type (void);
static HMODULE gio_dll = NULL;
#ifndef GLIB_STATIC_COMPILATION
BOOL WINAPI DllMain (HINSTANCE hinstDLL,
DWORD fdwReason,
LPVOID lpvReserved);
BOOL WINAPI
DllMain (HINSTANCE hinstDLL,
DWORD fdwReason,
LPVOID lpvReserved)
{
if (fdwReason == DLL_PROCESS_ATTACH)
{
gio_dll = hinstDLL;
gio_win32_appinfo_init (FALSE);
}
return TRUE;
}
#elif defined(G_HAS_CONSTRUCTORS) /* && G_PLATFORM_WIN32 && GLIB_STATIC_COMPILATION */
extern void glib_win32_init (void);
extern void gobject_win32_init (void);
#ifdef G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA
#pragma G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(giomodule_init_ctor)
#endif
G_DEFINE_CONSTRUCTOR (giomodule_init_ctor)
static void
giomodule_init_ctor (void)
{
/* When built dynamically, module initialization is done through DllMain
* function which is called when the dynamic library is loaded by the glib
* module AFTER loading gobject. So, in dynamic configuration glib and
* gobject are always initialized BEFORE gio.
*
* When built statically, initialization mechanism relies on hooking
* functions to the CRT section directly at compilation time. As we don't
* control how each compilation unit will be built and in which order, we
* obtain the same kind of issue as the "static initialization order fiasco".
* In this case, we must ensure explicitly that glib and gobject are always
* well initialized BEFORE gio.
*/
glib_win32_init ();
gobject_win32_init ();
gio_win32_appinfo_init (FALSE);
}
#else /* G_PLATFORM_WIN32 && GLIB_STATIC_COMPILATION && !G_HAS_CONSTRUCTORS */
#error Your platform/compiler is missing constructor support
#endif /* GLIB_STATIC_COMPILATION */
void *
_g_io_win32_get_module (void)
{
if (!gio_dll)
GetModuleHandleEx (GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
(LPCWSTR) _g_io_win32_get_module,
&gio_dll);
return gio_dll;
}
#endif /* G_PLATFORM_WIN32 */
void
_g_io_modules_ensure_extension_points_registered (void)
{
static gsize registered_extensions = FALSE;
GIOExtensionPoint *ep;
if (g_once_init_enter (&registered_extensions))
{
#if defined(G_OS_UNIX) && !defined(__APPLE__)
#if !GLIB_CHECK_VERSION (3, 0, 0)
ep = g_io_extension_point_register (G_DESKTOP_APP_INFO_LOOKUP_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_DESKTOP_APP_INFO_LOOKUP);
#endif
#endif
ep = g_io_extension_point_register (G_LOCAL_FILE_MONITOR_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_FILE_MONITOR);
ep = g_io_extension_point_register (G_NFS_FILE_MONITOR_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_FILE_MONITOR);
ep = g_io_extension_point_register (G_VOLUME_MONITOR_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_VOLUME_MONITOR);
ep = g_io_extension_point_register (G_NATIVE_VOLUME_MONITOR_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_NATIVE_VOLUME_MONITOR);
ep = g_io_extension_point_register (G_VFS_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_VFS);
ep = g_io_extension_point_register ("gsettings-backend");
g_io_extension_point_set_required_type (ep, G_TYPE_OBJECT);
ep = g_io_extension_point_register (G_PROXY_RESOLVER_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_PROXY_RESOLVER);
ep = g_io_extension_point_register (G_PROXY_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_PROXY);
ep = g_io_extension_point_register (G_TLS_BACKEND_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_TLS_BACKEND);
ep = g_io_extension_point_register (G_NETWORK_MONITOR_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_NETWORK_MONITOR);
ep = g_io_extension_point_register (G_NOTIFICATION_BACKEND_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_NOTIFICATION_BACKEND);
ep = g_io_extension_point_register (G_DEBUG_CONTROLLER_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_DEBUG_CONTROLLER);
ep = g_io_extension_point_register (G_MEMORY_MONITOR_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_MEMORY_MONITOR);
ep = g_io_extension_point_register (G_POWER_PROFILE_MONITOR_EXTENSION_POINT_NAME);
g_io_extension_point_set_required_type (ep, G_TYPE_POWER_PROFILE_MONITOR);
g_once_init_leave (&registered_extensions, TRUE);
}
}
static gchar *
get_gio_module_dir (void)
{
gchar *module_dir;
gboolean is_setuid = GLIB_PRIVATE_CALL (g_check_setuid) ();
/* If running as setuid, loading modules from an arbitrary directory
* controlled by the unprivileged user who is running the program could allow
* for execution of arbitrary code (in constructors in modules).
* Don’t allow it.
*
* If a setuid program somehow needs to load additional GIO modules, it should
* explicitly call g_io_modules_scan_all_in_directory(). */
module_dir = !is_setuid ? g_strdup (g_getenv ("GIO_MODULE_DIR")) : NULL;
if (module_dir == NULL)
{
#ifdef G_OS_WIN32
gchar *install_dir;
install_dir = g_win32_get_package_installation_directory_of_module (gio_dll);
module_dir = g_build_filename (install_dir,
"lib", "gio", "modules",
NULL);
g_free (install_dir);
#else
module_dir = g_strdup (GIO_MODULE_DIR);
#ifdef __APPLE__
#include "TargetConditionals.h"
/* Only auto-relocate on macOS, not watchOS etc; older macOS SDKs only define TARGET_OS_MAC */
#if (defined (TARGET_OS_OSX) && TARGET_OS_OSX) || \
(!defined (TARGET_OS_OSX) && defined (TARGET_OS_MAC) && TARGET_OS_MAC)
#include <dlfcn.h>
{
g_autofree gchar *path = NULL;
g_autofree gchar *possible_dir = NULL;
Dl_info info;
if (dladdr (get_gio_module_dir, &info))
{
/* Gets path to the PREFIX/lib directory */
path = g_path_get_dirname (info.dli_fname);
possible_dir = g_build_filename (path, "gio", "modules", NULL);
if (g_file_test (possible_dir, G_FILE_TEST_IS_DIR))
{
g_free (module_dir);
module_dir = g_steal_pointer (&possible_dir);
}
}
}
#endif
#endif
#endif
}
return module_dir;
}
void
_g_io_modules_ensure_loaded (void)
{
static gsize loaded_dirs = FALSE;
const char *module_path;
GIOModuleScope *scope;
_g_io_modules_ensure_extension_points_registered ();
if (g_once_init_enter (&loaded_dirs))
{
gboolean is_setuid = GLIB_PRIVATE_CALL (g_check_setuid) ();
gchar *module_dir;
scope = g_io_module_scope_new (G_IO_MODULE_SCOPE_BLOCK_DUPLICATES);
/* First load any overrides, extras (but not if running as setuid!) */
module_path = !is_setuid ? g_getenv ("GIO_EXTRA_MODULES") : NULL;
if (module_path)
{
gchar **paths;
int i;
paths = g_strsplit (module_path, G_SEARCHPATH_SEPARATOR_S, 0);
for (i = 0; paths[i] != NULL; i++)
{
g_io_modules_scan_all_in_directory_with_scope (paths[i], scope);
}
g_strfreev (paths);
}
/* Then load the compiled in path */
module_dir = get_gio_module_dir ();
g_io_modules_scan_all_in_directory_with_scope (module_dir, scope);
g_free (module_dir);
g_io_module_scope_free (scope);
/* Initialize types from built-in "modules" */
g_type_ensure (g_null_settings_backend_get_type ());
g_type_ensure (g_memory_settings_backend_get_type ());
g_type_ensure (g_keyfile_settings_backend_get_type ());
g_type_ensure (g_power_profile_monitor_dbus_get_type ());
#if defined(HAVE_INOTIFY_INIT1)
g_type_ensure (g_inotify_file_monitor_get_type ());
#endif
#if defined(HAVE_KQUEUE)
g_type_ensure (g_kqueue_file_monitor_get_type ());
#endif
#ifdef G_OS_WIN32
g_type_ensure (_g_win32_volume_monitor_get_type ());
g_type_ensure (g_win32_file_monitor_get_type ());
g_type_ensure (g_registry_settings_backend_get_type ());
#endif
#ifdef HAVE_COCOA
g_type_ensure (g_nextstep_settings_backend_get_type ());
g_type_ensure (g_osx_app_info_get_type ());
g_type_ensure (g_osx_network_monitor_get_type ());
#endif
#ifdef G_OS_UNIX
g_type_ensure (_g_unix_volume_monitor_get_type ());
g_type_ensure (g_debug_controller_dbus_get_type ());
g_type_ensure (g_fdo_notification_backend_get_type ());
g_type_ensure (g_gtk_notification_backend_get_type ());
g_type_ensure (g_portal_notification_backend_get_type ());
g_type_ensure (g_memory_monitor_dbus_get_type ());
g_type_ensure (g_memory_monitor_portal_get_type ());
g_type_ensure (g_network_monitor_portal_get_type ());
g_type_ensure (g_power_profile_monitor_portal_get_type ());
g_type_ensure (g_proxy_resolver_portal_get_type ());
#endif
#if MAC_OS_X_VERSION_MIN_REQUIRED >= 1090
g_type_ensure (g_cocoa_notification_backend_get_type ());
#endif
#ifdef G_OS_WIN32
g_type_ensure (g_win32_notification_backend_get_type ());
g_type_ensure (_g_winhttp_vfs_get_type ());
g_type_ensure (g_memory_monitor_win32_get_type ());
#endif
g_type_ensure (_g_local_vfs_get_type ());
g_type_ensure (_g_dummy_proxy_resolver_get_type ());
g_type_ensure (_g_http_proxy_get_type ());
g_type_ensure (_g_https_proxy_get_type ());
g_type_ensure (_g_socks4a_proxy_get_type ());
g_type_ensure (_g_socks4_proxy_get_type ());
g_type_ensure (_g_socks5_proxy_get_type ());
g_type_ensure (_g_dummy_tls_backend_get_type ());
g_type_ensure (g_network_monitor_base_get_type ());
#ifdef HAVE_NETLINK
g_type_ensure (_g_network_monitor_netlink_get_type ());
g_type_ensure (_g_network_monitor_nm_get_type ());
#endif
#ifdef G_OS_WIN32
g_type_ensure (_g_win32_network_monitor_get_type ());
#endif
g_once_init_leave (&loaded_dirs, TRUE);
}
}
static void
g_io_extension_point_free (GIOExtensionPoint *ep)
{
g_free (ep->name);
g_free (ep);
}
/**
* g_io_extension_point_register:
* @name: The name of the extension point
*
* Registers an extension point.
*
* Returns: (transfer none): the new #GIOExtensionPoint. This object is
* owned by GIO and should not be freed.
*/
GIOExtensionPoint *
g_io_extension_point_register (const char *name)
{
GIOExtensionPoint *ep;
G_LOCK (extension_points);
if (extension_points == NULL)
extension_points = g_hash_table_new_full (g_str_hash,
g_str_equal,
NULL,
(GDestroyNotify)g_io_extension_point_free);
ep = g_hash_table_lookup (extension_points, name);
if (ep != NULL)
{
G_UNLOCK (extension_points);
return ep;
}
ep = g_new0 (GIOExtensionPoint, 1);
ep->name = g_strdup (name);
g_hash_table_insert (extension_points, ep->name, ep);
G_UNLOCK (extension_points);
return ep;
}
/**
* g_io_extension_point_lookup:
* @name: the name of the extension point
*
* Looks up an existing extension point.
*
* Returns: (transfer none): the #GIOExtensionPoint, or %NULL if there
* is no registered extension point with the given name.
*/
GIOExtensionPoint *
g_io_extension_point_lookup (const char *name)
{
GIOExtensionPoint *ep;
G_LOCK (extension_points);
ep = NULL;
if (extension_points != NULL)
ep = g_hash_table_lookup (extension_points, name);
G_UNLOCK (extension_points);
return ep;
}
/**
* g_io_extension_point_set_required_type:
* @extension_point: a #GIOExtensionPoint
* @type: the #GType to require
*
* Sets the required type for @extension_point to @type.
* All implementations must henceforth have this type.
*/
void
g_io_extension_point_set_required_type (GIOExtensionPoint *extension_point,
GType type)
{
extension_point->required_type = type;
}
/**
* g_io_extension_point_get_required_type:
* @extension_point: a #GIOExtensionPoint
*
* Gets the required type for @extension_point.
*
* Returns: the #GType that all implementations must have,
* or %G_TYPE_INVALID if the extension point has no required type
*/
GType
g_io_extension_point_get_required_type (GIOExtensionPoint *extension_point)
{
return extension_point->required_type;
}
static void
lazy_load_modules (GIOExtensionPoint *extension_point)
{
GIOModule *module;
GList *l;
for (l = extension_point->lazy_load_modules; l != NULL; l = l->next)
{
module = l->data;
if (!module->initialized)
{
if (g_type_module_use (G_TYPE_MODULE (module)))
g_type_module_unuse (G_TYPE_MODULE (module)); /* Unload */
else
g_printerr ("Failed to load module: %s\n",
module->filename);
}
}
}
/**
* g_io_extension_point_get_extensions:
* @extension_point: a #GIOExtensionPoint
*
* Gets a list of all extensions that implement this extension point.
* The list is sorted by priority, beginning with the highest priority.
*
* Returns: (element-type GIOExtension) (transfer none): a #GList of
* #GIOExtensions. The list is owned by GIO and should not be
* modified.
*/
GList *
g_io_extension_point_get_extensions (GIOExtensionPoint *extension_point)
{
g_return_val_if_fail (extension_point != NULL, NULL);
lazy_load_modules (extension_point);
return extension_point->extensions;
}
/**
* g_io_extension_point_get_extension_by_name:
* @extension_point: a #GIOExtensionPoint
* @name: the name of the extension to get
*
* Finds a #GIOExtension for an extension point by name.
*
* Returns: (transfer none): the #GIOExtension for @extension_point that has the
* given name, or %NULL if there is no extension with that name
*/
GIOExtension *
g_io_extension_point_get_extension_by_name (GIOExtensionPoint *extension_point,
const char *name)
{
GList *l;
g_return_val_if_fail (name != NULL, NULL);
lazy_load_modules (extension_point);
for (l = extension_point->extensions; l != NULL; l = l->next)
{
GIOExtension *e = l->data;
if (e->name != NULL &&
strcmp (e->name, name) == 0)
return e;
}
return NULL;
}
static gint
extension_prio_compare (gconstpointer a,
gconstpointer b)
{
const GIOExtension *extension_a = a, *extension_b = b;
if (extension_a->priority > extension_b->priority)
return -1;
if (extension_b->priority > extension_a->priority)
return 1;
return 0;
}
/**
* g_io_extension_point_implement:
* @extension_point_name: the name of the extension point
* @type: the #GType to register as extension
* @extension_name: the name for the extension
* @priority: the priority for the extension
*
* Registers @type as extension for the extension point with name
* @extension_point_name.
*
* If @type has already been registered as an extension for this
* extension point, the existing #GIOExtension object is returned.
*
* Returns: (transfer none): a #GIOExtension object for #GType
*/
GIOExtension *
g_io_extension_point_implement (const char *extension_point_name,
GType type,
const char *extension_name,
gint priority)
{
GIOExtensionPoint *extension_point;
GIOExtension *extension;
GList *l;
g_return_val_if_fail (extension_point_name != NULL, NULL);
extension_point = g_io_extension_point_lookup (extension_point_name);
if (extension_point == NULL)
{
g_warning ("Tried to implement non-registered extension point %s", extension_point_name);
return NULL;
}
if (extension_point->required_type != 0 &&
!g_type_is_a (type, extension_point->required_type))
{
g_warning ("Tried to register an extension of the type %s to extension point %s. "
"Expected type is %s.",
g_type_name (type),
extension_point_name,
g_type_name (extension_point->required_type));
return NULL;
}
/* It's safe to register the same type multiple times */
for (l = extension_point->extensions; l != NULL; l = l->next)
{
extension = l->data;
if (extension->type == type)
return extension;
}
extension = g_slice_new0 (GIOExtension);
extension->type = type;
extension->name = g_strdup (extension_name);
extension->priority = priority;
extension_point->extensions = g_list_insert_sorted (extension_point->extensions,
extension, extension_prio_compare);
return extension;
}
/**
* g_io_extension_ref_class:
* @extension: a #GIOExtension
*
* Gets a reference to the class for the type that is
* associated with @extension.
*
* Returns: (transfer full): the #GTypeClass for the type of @extension
*/
GTypeClass *
g_io_extension_ref_class (GIOExtension *extension)
{
return g_type_class_ref (extension->type);
}
/**
* g_io_extension_get_type:
* @extension: a #GIOExtension
*
* Gets the type associated with @extension.
*
* Returns: the type of @extension
*/
GType
g_io_extension_get_type (GIOExtension *extension)
{
return extension->type;
}
/**
* g_io_extension_get_name:
* @extension: a #GIOExtension
*
* Gets the name under which @extension was registered.
*
* Note that the same type may be registered as extension
* for multiple extension points, under different names.
*
* Returns: the name of @extension.
*/
const char *
g_io_extension_get_name (GIOExtension *extension)
{
return extension->name;
}
/**
* g_io_extension_get_priority:
* @extension: a #GIOExtension
*
* Gets the priority with which @extension was registered.
*
* Returns: the priority of @extension
*/
gint
g_io_extension_get_priority (GIOExtension *extension)
{
return extension->priority;
}
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