nslookup: do not print "No answer" for NODATA replies, closes 13006

Only print when there was no answer at all.

function                                             old     new   delta
send_queries                                        1834    1813     -21

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 22 insertions, 6 deletions

diff --git a/networking/nslookup.c b/networking/nslookup.c
index 5aa2b35d2..c43ad46f3 100644
--- a/networking/nslookup.c
+++ b/networking/nslookup.c
@@ -349,6 +349,8 @@ static int parse_reply(const unsigned char *msg, size_t len)
         header = (HEADER *)msg;
         if (!header->aa)
                 printf("Non-authoritative answer:\n");
+        else if (option_mask32 & OPT_debug)
+                printf("Non-authoritative answer:\n" + 4);
 
         if (ns_initparse(msg, len, &handle) != 0) {
                 //printf("Unable to parse reply: %s\n", strerror(errno));
@@ -381,7 +383,7 @@ static int parse_reply(const unsigned char *msg, size_t len)
                                 return -1;
                         }
                         inet_ntop(AF_INET6, ns_rr_rdata(rr), astr, sizeof(astr));
-                        /* bind-utils-9.11.3 uses the same format for A and AAAA answers */
+                        /* bind-utils 9.11.3 uses the same format for A and AAAA answers */
                         printf("Name:\t%s\nAddress: %s\n", ns_rr_name(rr), astr);
                         break;
 #endif
@@ -580,7 +582,7 @@ static int send_queries(struct ns *ns)
                         printf("Address:\t%s\n\n",
                                 auto_string(xmalloc_sockaddr2dotted(&ns->lsa->u.sa))
                         );
-                        /* In "Address", bind-utils-9.11.3 show port after a hash: "1.2.3.4#53" */
+                        /* In "Address", bind-utils 9.11.3 show port after a hash: "1.2.3.4#53" */
                         /* Should we do the same? */
                 }
 
@@ -640,12 +642,26 @@ static int send_queries(struct ns *ns)
                                 printf("*** Can't find %s: Parse error\n", G.query[qn].name);
                                 G.exitcode = EXIT_FAILURE;
                                 break;
-
-                        case 0:
-                                printf("*** Can't find %s: No answer\n", G.query[qn].name);
-                                break;
+                        /* bind-utils 9.11.25 just says nothing in this case */
+                        //case 0:
+                        //      break;
                         }
                 }
+/* NB: in case of authoritative, empty answer (NODATA), IOW: one with
+ * ns_msg_count() == 0, bind-utils 9.11.25 shows no trace of this answer
+ * (unless -debug, where it says:
+ * ------------
+ *     QUESTIONS:
+ *     host.com, type = AAAA, class = IN
+ *     ANSWERS:
+ *     AUTHORITY RECORDS:
+ *     ADDITIONAL RECORDS:
+ * ------------
+ * ). Due to printing of below '\n', we do show an additional empty line.
+ * This is better than not showing any indication of this reply at all,
+ * yet maintains "compatibility". I wonder whether it's better to break compat
+ * and emit something more meaningful, e.g. print "Empty answer (NODATA)"?
+ */
                 bb_putchar('\n');
                 n_replies++;
                 if (n_replies >= G.query_count)