ctrl: on parse errors, return a detailed message to sender

The recently added ctrl_cmd_parse2() returns non-NULL cmd with error messages
upon parsing errors. In handle_control_read(), use ctrl_cmd_parse2() and send
those back to the CTRL command sender as reply.

Retain the previous "Command parser error" reply only in case ctrl_cmd_parse2()
should return NULL, which shouldn't actually happen at all.

Change-Id: Ie35a02555b76913bb12734a76fc40fde7ffb244d

2 files changed, 24 insertions, 12 deletions

diff --git a/src/ctrl/control_if.c b/src/ctrl/control_if.c
index 5c73b631..17a012a9 100644
--- a/src/ctrl/control_if.c
+++ b/src/ctrl/control_if.c
@@ -381,14 +381,10 @@ int ctrl_handle_msg(struct ctrl_handle *ctrl, struct ctrl_connection *ccon, stru
 
 	msg->l2h = iph_ext->data;
 
-	cmd = ctrl_cmd_parse(ccon, msg);
+	cmd = ctrl_cmd_parse2(ccon, msg);
 
-	if (cmd) {
-		cmd->ccon = ccon;
-		if (ctrl_cmd_handle(ctrl, cmd, ctrl->data) != CTRL_CMD_HANDLED) {
-			ctrl_cmd_send(&ccon->write_queue, cmd);
-		}
-	} else {
+	if (!cmd) {
+		/* should never happen */
 		cmd = talloc_zero(ccon, struct ctrl_cmd);
 		if (!cmd)
 			return -ENOMEM;
@@ -396,10 +392,23 @@ int ctrl_handle_msg(struct ctrl_handle *ctrl, struct ctrl_connection *ccon, stru
 		cmd->type = CTRL_TYPE_ERROR;
 		cmd->id = "err";
 		cmd->reply = "Command parser error.";
+	}
+
+	if (cmd->type != CTRL_TYPE_ERROR) {
+		cmd->ccon = ccon;
+		if (ctrl_cmd_handle(ctrl, cmd, ctrl->data) == CTRL_CMD_HANDLED) {
+			/* On CTRL_CMD_HANDLED, no reply needs to be sent back. */
+			talloc_free(cmd);
+			cmd = NULL;
+		}
+	}
+
+	if (cmd) {
+		/* There is a reply or error that should be reported back to the sender. */
 		ctrl_cmd_send(&ccon->write_queue, cmd);
+		talloc_free(cmd);
 	}
 
-	talloc_free(cmd);
 	return 0;
 }
 
@@ -894,13 +903,16 @@ struct ctrl_cmd *ctrl_cmd_exec_from_string(struct ctrl_handle *ch, const char *c
 	osmo_strlcpy((char *)msg->data, cmdstr, msgb_tailroom(msg));
 	msgb_put(msg, strlen(cmdstr));
 
-	cmd = ctrl_cmd_parse(ch, msg);
+	cmd = ctrl_cmd_parse2(ch, msg);
 	msgb_free(msg);
 	if (!cmd)
 		return NULL;
-	if (ctrl_cmd_handle(ch, cmd, NULL) < 0) {
+	if (cmd->type == CTRL_TYPE_ERROR)
+		return cmd;
+	if (ctrl_cmd_handle(ch, cmd, NULL) == CTRL_CMD_HANDLED) {
+		/* No reply should be sent back. */
 		talloc_free(cmd);
-		return NULL;
+		cmd = NULL;
 	}
 	return cmd;
 }
diff --git a/tests/ctrl/ctrl_test.c b/tests/ctrl/ctrl_test.c
index b1d4f237..39ec61a8 100644
--- a/tests/ctrl/ctrl_test.c
+++ b/tests/ctrl/ctrl_test.c
@@ -76,7 +76,7 @@ static void assert_test(struct ctrl_handle *ctrl, struct ctrl_connection *ccon,
 	printf("test: '%s'\n", osmo_escape_str(t->cmd_str, -1));
 	printf("parsing:\n");
 
-	cmd = ctrl_cmd_parse(ctx, msg);
+	cmd = ctrl_cmd_parse2(ctx, msg);
 	OSMO_ASSERT(cmd);
 
 	OSMO_ASSERT(t->expect_parsed.type == cmd->type);