ctl: improve error detection and send an error message to the client

4 files changed, 43 insertions, 23 deletions

diff --git a/src/knot/ctl/commands.c b/src/knot/ctl/commands.c
index b168f3063..1f53014f7 100644
--- a/src/knot/ctl/commands.c
+++ b/src/knot/ctl/commands.c
@@ -1,4 +1,4 @@
-/*  Copyright (C) 2024 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+/*  Copyright (C) 2025 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -161,7 +161,7 @@ static void ctl_log_conf_data(knot_ctl_data_t *data)
 	}
 }
 
-static void send_error(ctl_args_t *args, const char *msg)
+void ctl_send_error(ctl_args_t *args, const char *msg)
 {
 	knot_ctl_data_t data;
 	memcpy(&data, args->data, sizeof(data));
@@ -215,7 +215,7 @@ static int zones_apply(ctl_args_t *args, int (*fcn)(zone_t *, ctl_args_t *))
 		if (failed) {
 			ret = KNOT_CTL_EZONE;
 			log_ctl_error("control, error (%s)", knot_strerror(ret));
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 		}
 
 		return KNOT_EOK;
@@ -230,7 +230,7 @@ static int zones_apply(ctl_args_t *args, int (*fcn)(zone_t *, ctl_args_t *))
 		if (ret != KNOT_EOK) {
 			log_ctl_zone_str_error(args->data[KNOT_CTL_IDX_ZONE],
 			                       "control, error (%s)", knot_strerror(ret));
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 		}
 
 		// Get next zone name.
@@ -730,7 +730,7 @@ static int zones_apply_backup(ctl_args_t *args, bool restore_mode)
 
 		/* Warning: zone name in the control command params discarded here. */
 		args->data[KNOT_CTL_IDX_ZONE] = NULL;
-		send_error(args, knot_strerror(ret));
+		ctl_send_error(args, knot_strerror(ret));
 		return KNOT_CTL_EZONE;
 	}
 
@@ -742,7 +742,7 @@ static int zones_apply_backup(ctl_args_t *args, bool restore_mode)
 		log_ctl_error("control, QUIC %s error (%s)",
 		              restore_mode ? "restore" : "backup",
 		              knot_strerror(ret));
-		send_error(args, knot_strerror(ret));
+		ctl_send_error(args, knot_strerror(ret));
 		ret = KNOT_EOK;
 		goto done;
 	}
@@ -753,7 +753,7 @@ static int zones_apply_backup(ctl_args_t *args, bool restore_mode)
 		ret = global_backup(ctx, &args->server->catalog, NULL);
 		if (ret != KNOT_EOK) {
 			log_ctl_error("control, error (%s)", knot_strerror(ret));
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 			ret = KNOT_EOK;
 			goto done;
 		}
@@ -1672,7 +1672,7 @@ static int orphans_purge(ctl_args_t *args)
 		}
 
 		if (failed) {
-			send_error(args, knot_strerror(KNOT_CTL_EZONE));
+			ctl_send_error(args, knot_strerror(KNOT_CTL_EZONE));
 		}
 	} else {
 		knot_dname_storage_t buff;
@@ -1684,7 +1684,7 @@ static int orphans_purge(ctl_args_t *args)
 				log_ctl_zone_str_error(args->data[KNOT_CTL_IDX_ZONE],
 				                       "control, error (%s)",
 				                       knot_strerror(KNOT_EINVAL));
-				send_error(args, knot_strerror(KNOT_EINVAL));
+				ctl_send_error(args, knot_strerror(KNOT_EINVAL));
 				return KNOT_EINVAL;
 			}
 			knot_dname_to_lower(zone_name);
@@ -1719,7 +1719,7 @@ static int orphans_purge(ctl_args_t *args)
 				}
 
 				if (failed) {
-					send_error(args, knot_strerror(KNOT_ERROR));
+					ctl_send_error(args, knot_strerror(KNOT_ERROR));
 					failed = false;
 				}
 			}
@@ -1817,7 +1817,7 @@ static int common_stats(ctl_args_t *args, zone_t *zone)
 #define STATS_CHECK(ret, send) { \
 	if (ret != KNOT_EOK) { \
 		if ((send)) { /* Prevents duplicit zone error logs. */ \
-			send_error(args, knot_strerror(ret)); \
+			ctl_send_error(args, knot_strerror(ret)); \
 		} \
 		return ret; \
 	} \
@@ -1994,7 +1994,7 @@ static int ctl_server(ctl_args_t *args, ctl_cmd_t cmd)
 	case CTL_STATUS:
 		ret = server_status(args);
 		if (ret != KNOT_EOK) {
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 		}
 		break;
 	case CTL_STOP:
@@ -2006,7 +2006,7 @@ static int ctl_server(ctl_args_t *args, ctl_cmd_t cmd)
 			ret = server_reload(args->server, RELOAD_FULL);
 		}
 		if (ret != KNOT_EOK) {
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 		}
 		break;
 	default:
@@ -2176,7 +2176,7 @@ static int ctl_conf_txn(ctl_args_t *args, ctl_cmd_t cmd)
 	}
 
 	if (ret != KNOT_EOK) {
-		send_error(args, knot_strerror(ret));
+		ctl_send_error(args, knot_strerror(ret));
 	}
 
 	return ret;
@@ -2229,7 +2229,7 @@ static int ctl_conf_list(ctl_args_t *args, ctl_cmd_t cmd)
 			ret = conf_io_list(key0, key1, id, schema, current, &io);
 		}
 		if (ret != KNOT_EOK) {
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 			break;
 		}
 
@@ -2274,7 +2274,7 @@ static int ctl_conf_read(ctl_args_t *args, ctl_cmd_t cmd)
 			ret = KNOT_EINVAL;
 		}
 		if (ret != KNOT_EOK) {
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 			break;
 		}
 
@@ -2293,7 +2293,7 @@ static int ctl_conf_modify(ctl_args_t *args, ctl_cmd_t cmd)
 	// Start child transaction.
 	int ret = conf_io_begin(true);
 	if (ret != KNOT_EOK) {
-		send_error(args, knot_strerror(ret));
+		ctl_send_error(args, knot_strerror(ret));
 		return ret;
 	}
 
@@ -2317,7 +2317,7 @@ static int ctl_conf_modify(ctl_args_t *args, ctl_cmd_t cmd)
 			ret = KNOT_EINVAL;
 		}
 		if (ret != KNOT_EOK) {
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 			break;
 		}
 
@@ -2332,7 +2332,7 @@ static int ctl_conf_modify(ctl_args_t *args, ctl_cmd_t cmd)
 	if (ret == KNOT_EOK) {
 		ret = conf_io_commit(true);
 		if (ret != KNOT_EOK) {
-			send_error(args, knot_strerror(ret));
+			ctl_send_error(args, knot_strerror(ret));
 		}
 	} else {
 		conf_io_abort(true);
diff --git a/src/knot/ctl/commands.h b/src/knot/ctl/commands.h
index 2ea958747..6a7aad54a 100644
--- a/src/knot/ctl/commands.h
+++ b/src/knot/ctl/commands.h
@@ -1,4 +1,4 @@
-/*  Copyright (C) 2024 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+/*  Copyright (C) 2025 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -166,3 +166,11 @@ int ctl_exec(ctl_cmd_t cmd, ctl_args_t *args);
  * \return True if presented.
  */
 bool ctl_has_flag(const char *flags, const char *flag);
+
+/*!
+ * Send control error message.
+ *
+ * \param[in] args  Command arguments.
+ * \param[in] msg   Error message.
+ */
+void ctl_send_error(ctl_args_t *args, const char *msg);
diff --git a/src/knot/ctl/process.c b/src/knot/ctl/process.c
index 96bc398e1..cf6d7ab5e 100644
--- a/src/knot/ctl/process.c
+++ b/src/knot/ctl/process.c
@@ -107,7 +107,14 @@ int ctl_process(knot_ctl_t *ctl, server_t *server, int thread_idx, bool *exclusi
 		}
 
 		if ((cmd == CTL_CONF_COMMIT || cmd == CTL_CONF_ABORT) && !*exclusive) {
-			log_ctl_warning("control, invalid reception of '%s'", cmd_name);
+			if (conf()->io.txn != NULL) {
+				cmd_ret = KNOT_EBUSY;
+			} else if (cmd == CTL_CONF_COMMIT) {
+				cmd_ret = KNOT_TXN_ENOTEXISTS;
+			}
+			if (cmd_ret != KNOT_EOK) {
+				ctl_send_error(&args, knot_strerror(cmd_ret));
+			}
 			cmd_exec = false;
 		}
 
diff --git a/tests-extra/tests/ctl/basic/test.py b/tests-extra/tests/ctl/basic/test.py
index a5defec8d..7f5b3b6e4 100644
--- a/tests-extra/tests/ctl/basic/test.py
+++ b/tests-extra/tests/ctl/basic/test.py
@@ -29,8 +29,13 @@ ctl.connect(os.path.join(knot.dir, "knot.sock"))
 ctl.send_block(cmd="conf-abort")
 resp = ctl.receive_block()
 
-ctl.send_block(cmd="conf-commit")
-resp = ctl.receive_block()
+try:
+    ctl.send_block(cmd="conf-commit")
+    resp = ctl.receive_block()
+except libknot.control.KnotCtlError as exc:
+    isset(exc.message == "no active transaction", "abort error code")
+else:
+    set_err("UNEXPECTED RETURN")
 
 # Add new zone.
 ctl.send_block(cmd="conf-begin")