Use strlcpy instead of memcpy for copying the slot name in pgstat.c.

Amit Kapila · Amit Kapila · commit 4f841ce3f7f4 · 2020-11-06T08:12:48.000+05:30
There is no outright bug here but it is better to be consistent with the usage at other places in the same file. In the passing, fix a wrong assertion in pgstat_recv_replslot. Author: Kyotaro Horiguchi Reviewed-by: Sawada Masahiko and Amit Kapila Discussion: https://postgr.es/m/20201104.175523.1704166915688949637.horikyota.ntt@gmail.com
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
@@ -1489,7 +1489,7 @@ pgstat_reset_replslot_counter(const char *name)
 		if (SlotIsPhysical(slot))
 			return;
 
-		memcpy(&msg.m_slotname, name, NAMEDATALEN);
+		strlcpy(msg.m_slotname, name, NAMEDATALEN);
 		msg.clearall = false;
 	}
 	else
@@ -1716,7 +1716,7 @@ pgstat_report_replslot(const char *slotname, int spilltxns, int spillcount,
 	 * Prepare and send the message
 	 */
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_REPLSLOT);
-	memcpy(&msg.m_slotname, slotname, NAMEDATALEN);
+	strlcpy(msg.m_slotname, slotname, NAMEDATALEN);
 	msg.m_drop = false;
 	msg.m_spill_txns = spilltxns;
 	msg.m_spill_count = spillcount;
@@ -1739,7 +1739,7 @@ pgstat_report_replslot_drop(const char *slotname)
 	PgStat_MsgReplSlot msg;
 
 	pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_REPLSLOT);
-	memcpy(&msg.m_slotname, slotname, NAMEDATALEN);
+	strlcpy(msg.m_slotname, slotname, NAMEDATALEN);
 	msg.m_drop = true;
 	pgstat_send(&msg, sizeof(PgStat_MsgReplSlot));
 }
@@ -6880,7 +6880,9 @@ pgstat_recv_replslot(PgStat_MsgReplSlot *msg, int len)
 	if (idx < 0)
 		return;
 
-	Assert(idx >= 0 && idx <= max_replication_slots);
+	/* it must be a valid replication slot index */
+	Assert(idx >= 0 && idx < max_replication_slots);
+
 	if (msg->m_drop)
 	{
 		/* Remove the replication slot statistics with the given name */
@@ -7113,7 +7115,7 @@ pgstat_replslot_index(const char *name, bool create_it)
 
 	/* Register new slot */
 	memset(&replSlotStats[nReplSlotStats], 0, sizeof(PgStat_ReplSlotStats));
-	memcpy(&replSlotStats[nReplSlotStats].slotname, name, NAMEDATALEN);
+	strlcpy(replSlotStats[nReplSlotStats].slotname, name, NAMEDATALEN);
 
 	return nReplSlotStats++;
 }
