/* 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 . */ /* * 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 #include #include #include #include #ifdef G_OS_UNIX #include #endif #ifdef G_OS_WIN32 #include /* For open() and close() prototypes. */ #endif #ifndef O_CLOEXEC #define O_CLOEXEC 0 #endif #include "gmoduleconf.h" #include "gstdio.h" /** * 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 using @file_name. * * Since 2.76, the search order/behavior is as follows: * * 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. * * If, at the end of all this, we have a file path that we can access on disk, * it is opened as a module. If not, @file_name is attempted to be opened as a * module verbatim in the hopes that the system implementation will somehow be * able to access it. If that is not possible, %NULL is returned. * * Note that this behaviour was different prior to 2.76, but there is some * overlap in functionality. If backwards compatibility is an issue, kindly * consult earlier #GModule documentation for the prior search order/behavior * of @file_name. * * 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(__ANDROID__) || !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); } #ifdef G_OS_WIN32 /* Binary compatibility versions. Not for newly compiled code. */ _GMODULE_EXTERN GModule * g_module_open_utf8 (const gchar *file_name, GModuleFlags flags); _GMODULE_EXTERN const gchar *g_module_name_utf8 (GModule *module); GModule* g_module_open_utf8 (const gchar *file_name, GModuleFlags flags) { return g_module_open (file_name, flags); } const gchar * g_module_name_utf8 (GModule *module) { return g_module_name (module); } #endif