[PATCH] batctl: event: don't print timestamp prefix for skipped events

[Sven Eckelmann <sven@narfation.org>]

The timestamp is printed before the event is parsed. Each parse function
can still decide to skip the event without printing anything In these cases
a bare "1234.567890: " fragment without newline remains on the line and the
next event is appended to it, corrupting the output stream.

Format the timestamp into a prefix string instead and let the parse
functions print it together with their first line.

Fixes: 5d7850e3582e ("batctl: Add command to monitor for netlink events")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 event.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/event.c b/event.c
index e061c2c..4a1085d 100644
--- a/event.c
+++ b/event.c
@@ -114,7 +114,7 @@ static const int tp_meter_mandatory[] = {
 	BATADV_ATTR_TPMETER_RESULT,
 };
 
-static void event_parse_tp_meter(struct nlattr **attrs)
+static void event_parse_tp_meter(struct nlattr **attrs, const char *prefix)
 {
 	const char *result_str;
 	uint32_t cookie;
@@ -155,10 +155,10 @@ static void event_parse_tp_meter(struct nlattr **attrs)
 		break;
 	}
 
-	printf("tp_meter 0x%08x: %s\n", cookie, result_str);
+	printf("%stp_meter 0x%08x: %s\n", prefix, cookie, result_str);
 }
 
-static void event_parse_set_mesh(struct nlattr **attrs)
+static void event_parse_set_mesh(struct nlattr **attrs, const char *prefix)
 {
 	static const int mesh_mandatory[] = {
 		BATADV_ATTR_MESH_IFINDEX,
@@ -183,7 +183,7 @@ static void event_parse_set_mesh(struct nlattr **attrs)
 			return;
 	}
 
-	printf("%s: set mesh:\n", meshif_name);
+	printf("%s%s: set mesh:\n", prefix, meshif_name);
 
 	if (attrs[BATADV_ATTR_AGGREGATED_OGMS_ENABLED])
 		printf("* aggregated_ogms %s\n",
@@ -287,7 +287,7 @@ static void event_parse_set_mesh(struct nlattr **attrs)
 		       nla_get_u32(attrs[BATADV_ATTR_ORIG_INTERVAL]));
 }
 
-static void event_parse_set_hardif(struct nlattr **attrs)
+static void event_parse_set_hardif(struct nlattr **attrs, const char *prefix)
 {
 	static const int hardif_mandatory[] = {
 		BATADV_ATTR_MESH_IFINDEX,
@@ -325,7 +325,7 @@ static void event_parse_set_hardif(struct nlattr **attrs)
 			return;
 	}
 
-	printf("%s (%s): set hardif:\n", meshif_name, hardif_name);
+	printf("%s%s (%s): set hardif:\n", prefix, meshif_name, hardif_name);
 
 	if (attrs[BATADV_ATTR_HOP_PENALTY])
 		printf("* hop_penalty %u\n",
@@ -344,7 +344,7 @@ static void event_parse_set_hardif(struct nlattr **attrs)
 	}
 }
 
-static void event_parse_set_vlan(struct nlattr **attrs)
+static void event_parse_set_vlan(struct nlattr **attrs, const char *prefix)
 {
 	static const int vlan_mandatory[] = {
 		BATADV_ATTR_MESH_IFINDEX,
@@ -372,7 +372,7 @@ static void event_parse_set_vlan(struct nlattr **attrs)
 
 	vid = nla_get_u16(attrs[BATADV_ATTR_VLANID]);
 
-	printf("%s (vid %u): set vlan:\n", meshif_name, vid);
+	printf("%s%s (vid %u): set vlan:\n", prefix, meshif_name, vid);
 
 	if (attrs[BATADV_ATTR_AP_ISOLATION_ENABLED])
 		printf("* ap_isolation %s\n",
@@ -403,6 +403,7 @@ static int event_parse(struct nl_msg *msg, void *arg)
 	struct event_args *event_args = arg;
 	unsigned long long timestamp;
 	struct genlmsghdr *ghdr;
+	char prefix[32] = "";
 
 	if (!genlmsg_valid_hdr(nlh, 0))
 		return NL_OK;
@@ -417,24 +418,25 @@ static int event_parse(struct nl_msg *msg, void *arg)
 
 	if (event_args->mode != EVENT_TIME_NO) {
 		timestamp = get_timestamp(event_args);
-		printf("%llu.%06llu: ", timestamp / 1000000, timestamp % 1000000);
+		snprintf(prefix, sizeof(prefix), "%llu.%06llu: ",
+			 timestamp / 1000000, timestamp % 1000000);
 	}
 
 	switch (ghdr->cmd) {
 	case BATADV_CMD_TP_METER:
-		event_parse_tp_meter(attrs);
+		event_parse_tp_meter(attrs, prefix);
 		break;
 	case BATADV_CMD_SET_MESH:
-		event_parse_set_mesh(attrs);
+		event_parse_set_mesh(attrs, prefix);
 		break;
 	case BATADV_CMD_SET_HARDIF:
-		event_parse_set_hardif(attrs);
+		event_parse_set_hardif(attrs, prefix);
 		break;
 	case BATADV_CMD_SET_VLAN:
-		event_parse_set_vlan(attrs);
+		event_parse_set_vlan(attrs, prefix);
 		break;
 	default:
-		printf("Received unknown event %u\n", ghdr->cmd);
+		printf("%sReceived unknown event %u\n", prefix, ghdr->cmd);
 		break;
 	}
 

---
base-commit: e93995999e80513db80eba200ea682b5b15556af
change-id: 20260704-bugfixes-event-cac8fef8b398

Best regards,
--  
Sven Eckelmann <sven@narfation.org>