ifcfg-rh: add allow_filename_cb() argument to write-ifcfg-rh function

The function determines the filename automatically, but we
need to blacklist certain names.

That is, because NetworkManager keeps a list of loaded files
in memory. When writing a new file, we really want to choose
a filename that is not yet taken. For that we must not only
consider files on disk, but also files that existed on the last
time of loading.

src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-connection.c

@@ -206,6 +206,8 @@ commit_changes (NMSettingsConnection *connection,
 	if (!nms_ifcfg_rh_writer_write_connection (new_connection,
 	                                           IFCFG_DIR,
 	                                           filename,
+	                                           NULL,
+	                                           NULL,
 	                                           &ifcfg_path,
 	                                           &reread,
 	                                           &reread_same,

src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-plugin.c

@@ -594,7 +594,7 @@ add_connection (NMSettingsPlugin *config,
 	gs_unref_object NMConnection *reread = NULL;
 
 	if (save_to_disk) {
-		if (!nms_ifcfg_rh_writer_write_connection (connection, IFCFG_DIR, NULL, &path, &reread, NULL, error))
+		if (!nms_ifcfg_rh_writer_write_connection (connection, IFCFG_DIR, NULL, NULL, NULL, &path, &reread, NULL, error))
 			return NULL;
 	} else {
 		if (!nms_ifcfg_rh_writer_can_write_connection (connection, error))

src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-writer.c

@@ -3024,6 +3024,8 @@ static gboolean
 do_write_construct (NMConnection *connection,
                     const char *ifcfg_dir,
                     const char *filename,
+                    NMSIfcfgRHWriterAllowFilenameCb allow_filename_cb,
+                    gpointer allow_filename_user_data,
                     shvarFile **out_ifcfg,
                     GHashTable **out_blobs,
                     GHashTable **out_secrets,
@@ -3067,30 +3069,31 @@ do_write_construct (NMConnection *connection,
 
 		ifcfg_name = g_strdup (filename);
 	} else if (ifcfg_dir) {
-		char *escaped;
+		gs_free char *escaped = NULL;
+		int i_path;
 
 		escaped = escape_id (nm_setting_connection_get_id (s_con));
-		ifcfg_name = g_strdup_printf ("%s/ifcfg-%s", ifcfg_dir, escaped);
 
-		/* If a file with this path already exists then we need another name.
+		for (i_path = 0; i_path < 10000; i_path++) {
-		 * Multiple connections can have the same ID (ie if two connections with
+			gs_free char *path_candidate = NULL;
-		 * the same ID are visible to different users) but of course can't have
-		 * the same path.
-		 */
-		if (g_file_test (ifcfg_name, G_FILE_TEST_EXISTS)) {
-			guint32 idx = 0;
 
-			nm_clear_g_free (&ifcfg_name);
+			if (i_path == 0)
-			while (idx++ < 500) {
+				path_candidate = g_strdup_printf ("%s/ifcfg-%s", ifcfg_dir, escaped);
-				ifcfg_name = g_strdup_printf ("%s/ifcfg-%s-%u", ifcfg_dir, escaped, idx);
+			else
-				if (g_file_test (ifcfg_name, G_FILE_TEST_EXISTS) == FALSE)
+				path_candidate = g_strdup_printf ("%s/ifcfg-%s-%d", ifcfg_dir, escaped, i_path);
-					break;
+
-				nm_clear_g_free (&ifcfg_name);
+			if (   allow_filename_cb
-			}
+			    && !allow_filename_cb (path_candidate, allow_filename_user_data))
+				continue;
+
+			if (g_file_test (path_candidate, G_FILE_TEST_EXISTS))
+				continue;
+
+			ifcfg_name = g_steal_pointer (&path_candidate);
+			break;
 		}
-		g_free (escaped);
 
-		if (ifcfg_name == NULL) {
+		if (!ifcfg_name) {
 			g_set_error_literal (error, NM_SETTINGS_ERROR, NM_SETTINGS_ERROR_FAILED,
 			                     "Failed to find usable ifcfg file name");
 			return FALSE;
@@ -3377,6 +3380,8 @@ gboolean
 nms_ifcfg_rh_writer_write_connection (NMConnection *connection,
                                       const char *ifcfg_dir,
                                       const char *filename,
+                                      NMSIfcfgRHWriterAllowFilenameCb allow_filename_cb,
+                                      gpointer allow_filename_user_data,
                                       char **out_filename,
                                       NMConnection **out_reread,
                                       gboolean *out_reread_same,
@@ -3396,6 +3401,8 @@ nms_ifcfg_rh_writer_write_connection (NMConnection *connection,
 	if (!do_write_construct (connection,
 	                         ifcfg_dir,
 	                         filename,
+	                         allow_filename_cb,
+	                         allow_filename_user_data,
 	                         &ifcfg,
 	                         &blobs,
 	                         &secrets,

src/settings/plugins/ifcfg-rh/nms-ifcfg-rh-writer.h

@@ -22,12 +22,18 @@
 
 #include "nm-connection.h"
 
+
+typedef gboolean (*NMSIfcfgRHWriterAllowFilenameCb) (const char *check_filename,
+                                                     gpointer allow_filename_user_data);
+
 gboolean nms_ifcfg_rh_writer_can_write_connection (NMConnection *connection,
                                                    GError **error);
 
 gboolean nms_ifcfg_rh_writer_write_connection (NMConnection *connection,
                                                const char *ifcfg_dir,
                                                const char *filename,
+                                               NMSIfcfgRHWriterAllowFilenameCb allow_filename_cb,
+                                               gpointer allow_filename_user_data,
                                                char **out_filename,
                                                NMConnection **out_reread,
                                                gboolean *out_reread_same,

src/settings/plugins/ifcfg-rh/tests/test-ifcfg-rh.c

@@ -238,7 +238,7 @@ _assert_expected_content (NMConnection *connection, const char *filename, const
 		g_assert (_ifcfg_dir && _ifcfg_dir[0]); \
 		g_assert (_filename && _filename[0]); \
 		\
-		_success = nms_ifcfg_rh_writer_write_connection (_connection, _ifcfg_dir, _filename, NULL, _out_reread, _out_reread_same, &_error); \
+		_success = nms_ifcfg_rh_writer_write_connection (_connection, _ifcfg_dir, _filename, NULL, NULL, NULL, _out_reread, _out_reread_same, &_error); \
 		nmtst_assert_success (_success, _error); \
 		_assert_expected_content (_connection, _filename, _expected); \
 	} G_STMT_END
@@ -319,6 +319,8 @@ _writer_new_connection_reread (NMConnection *connection,
 	success = nms_ifcfg_rh_writer_write_connection (con_verified,
 	                                                ifcfg_dir,
 	                                                NULL,
+	                                                NULL,
+	                                                NULL,
 	                                                &filename,
 	                                                reread,
 	                                                out_reread_same,
@@ -394,6 +396,8 @@ _writer_new_connection_fail (NMConnection *connection,
 	success = nms_ifcfg_rh_writer_write_connection (connection_normalized,
 	                                                ifcfg_dir,
 	                                                NULL,
+	                                                NULL,
+	                                                NULL,
 	                                                &filename,
 	                                                &reread,
 	                                                NULL,