Merge branch 'nitpicks' into 'master'

add parameter check and improve doc-comments

See merge request !686

src/libknot/dname.h

@@ -368,7 +368,7 @@ int knot_dname_align(const uint8_t **d1, uint8_t d1_labels,
  *
  * Maximum length of such a domain name is KNOT_DNAME_MAXLEN characters.
  *
- * \param dst Memory to store converted name into.
+ * \param dst Memory to store converted name into.  dst[0] will contain the length.
  * \param src Source domain name.
  * \param pkt Source name packet (NULL if not any).
  *

src/libknot/packet/wire.h

@@ -376,7 +376,7 @@ static inline void knot_wire_set_opcode(uint8_t *packet, short opcode)
  *
  * \param packet Wire format of the packet.
  *
- * \return Flags with only the QR bit according to its setting in the packet.
+ * \return Nonzero for responses and zero for queries.
  */
 static inline uint8_t knot_wire_get_qr(const uint8_t *packet)
 {

src/libknot/rrset-dump.c

@@ -1756,6 +1756,10 @@ int knot_rrset_txt_dump_data(const knot_rrset_t      *rrset,
 	}
 
 	const knot_rdata_t *rr_data = knot_rdataset_at(&rrset->rrs, pos);
+	if (rr_data == NULL) {
+		return KNOT_EINVAL; /* bad pos or rrset->rrs */
+	}
+
 	uint8_t *data = knot_rdata_data(rr_data);
 	uint16_t data_len = knot_rdata_rdlen(rr_data);