libnm: add _nm_utils_check_module_file()

libnm-core/nm-utils.c

@@ -2478,6 +2478,90 @@ _nm_utils_check_file (const char *filename,
 	return TRUE;
 }
 
+
+static char *
+_resolve_module_file_name (const char *file_name)
+{
+	char *name = NULL;
+
+	/* g_module_open() is searching for the exact file to load,
+	 * but it doesn't give us a hook to check file permissions
+	 * and ownership. Reimplement the file name resolution.
+	 *
+	 * Copied from g_module_open(). */
+
+	/* 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
+	    && !g_str_has_suffix (file_name, "." G_MODULE_SUFFIX)) {
+		name = g_strconcat (file_name, "." G_MODULE_SUFFIX, NULL);
+		if (!g_file_test (name, G_FILE_TEST_IS_REGULAR)) {
+			g_free (name);
+			name = NULL;
+		}
+	}
+
+	/* g_module_open() would also try appending ".la". We don't do that
+	 * because we require the user to specify a shared library (directly). */
+
+	return name;
+}
+
+char *
+_nm_utils_check_module_file (const char *name,
+                             int check_owner,
+                             NMUtilsCheckFilePredicate check_file,
+                             gpointer user_data,
+                             GError **error)
+{
+	gs_free char *name_resolved = NULL;
+	char *s;
+
+	if (!g_path_is_absolute (name)) {
+		g_set_error (error,
+		             NM_VPN_PLUGIN_ERROR,
+		             NM_VPN_PLUGIN_ERROR_FAILED,
+		             _("path is not absolute (%s)"), name);
+		return NULL;
+	}
+
+	name_resolved = _resolve_module_file_name (name);
+
+	if (!name_resolved) {
+		g_set_error (error,
+		             NM_VPN_PLUGIN_ERROR,
+		             NM_VPN_PLUGIN_ERROR_FAILED,
+		             _("could not resolve plugin path (%s)"), name);
+		return NULL;
+	}
+
+	if (g_str_has_suffix (name_resolved, ".la")) {
+		/* g_module_open() treats files that end with .la special.
+		 * We don't want to parse the libtool archive. Just error out. */
+		g_set_error (error,
+		             NM_VPN_PLUGIN_ERROR,
+		             NM_VPN_PLUGIN_ERROR_FAILED,
+		             _("libtool archives are not supported (%s)"), name_resolved);
+		return NULL;
+	}
+
+	if (!_nm_utils_check_file (name_resolved,
+	                           check_owner,
+	                           check_file,
+	                           user_data,
+	                           NULL,
+	                           error)) {
+		return NULL;
+	}
+
+	s = name_resolved;
+	name_resolved = NULL;
+	return s;
+}
+
 /**********************************************************************************************/
 
 /**