From ebb779dc23bc61886a4a4d4cabece871b058f051 Mon Sep 17 00:00:00 2001
From: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
Date: Fri, 24 Nov 2017 15:24:57 +0200
Subject: [PATCH] resolved: inroduce dns_txt_item_new_empty() function

---
 src/resolve/resolved-dns-packet.c | 13 +++----------
 src/resolve/resolved-dns-rr.c     | 16 ++++++++++++++++
 src/resolve/resolved-dns-rr.h     |  1 +
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index 40f35475fdc..d7a839a8237 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -1698,16 +1698,9 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl
         case DNS_TYPE_SPF: /* exactly the same as TXT */
         case DNS_TYPE_TXT:
                 if (rdlength <= 0) {
-                        DnsTxtItem *i;
-                        /* RFC 6763, section 6.1 suggests to treat
-                         * empty TXT RRs as equivalent to a TXT record
-                         * with a single empty string. */
-
-                        i = malloc0(offsetof(DnsTxtItem, data) + 1); /* for safety reasons we add an extra NUL byte */
-                        if (!i)
-                                return -ENOMEM;
-
-                        rr->txt.items = i;
+                        r = dns_txt_item_new_empty(&rr->txt.items);
+                        if (r < 0)
+                                return r;
                 } else {
                         DnsTxtItem *last = NULL;
 
diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 898d5b3c364..eaea30f2272 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -1806,6 +1806,22 @@ DnsTxtItem *dns_txt_item_copy(DnsTxtItem *first) {
         return copy;
 }
 
+int dns_txt_item_new_empty(DnsTxtItem **ret) {
+        DnsTxtItem *i;
+
+        /* RFC 6763, section 6.1 suggests to treat
+         * empty TXT RRs as equivalent to a TXT record
+         * with a single empty string. */
+
+        i = malloc0(offsetof(DnsTxtItem, data) + 1); /* for safety reasons we add an extra NUL byte */
+        if (!i)
+                return -ENOMEM;
+
+        *ret = i;
+
+        return 0;
+}
+
 static const char* const dnssec_algorithm_table[_DNSSEC_ALGORITHM_MAX_DEFINED] = {
         /* Mnemonics as listed on https://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml */
         [DNSSEC_ALGORITHM_RSAMD5]             = "RSAMD5",
diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h
index 9faf4debe74..7a12fd5c8c3 100644
--- a/src/resolve/resolved-dns-rr.h
+++ b/src/resolve/resolved-dns-rr.h
@@ -341,6 +341,7 @@ int dns_resource_record_clamp_ttl(DnsResourceRecord **rr, uint32_t max_ttl);
 DnsTxtItem *dns_txt_item_free_all(DnsTxtItem *i);
 bool dns_txt_item_equal(DnsTxtItem *a, DnsTxtItem *b);
 DnsTxtItem *dns_txt_item_copy(DnsTxtItem *i);
+int dns_txt_item_new_empty(DnsTxtItem **ret);
 
 void dns_resource_record_hash_func(const void *i, struct siphash *state);
 
-- 
2.39.2