[2535] Handle escaped characters in TXTLikeImpl::toText()

src/lib/dns/rdata/generic/detail/txt_like.h

@@ -177,8 +177,6 @@ public:
     toText() const {
         std::string s;
 
-        // XXX: this implementation is not entirely correct.  for example, it
-        // should escape double-quotes if they appear in the character string.
         for (std::vector<std::vector<uint8_t> >::const_iterator it =
                  string_list_.begin();
              it != string_list_.end();
@@ -188,7 +186,22 @@ public:
                 s.push_back(' ');
             }
             s.push_back('"');
-            s.insert(s.end(), (*it).begin() + 1, (*it).end());
+            for (std::vector<uint8_t>::const_iterator c_it =
+                   (*it).begin() + 1;
+                 c_it != (*it).end();
+                 ++c_it) {
+                if ((*c_it < 0x20) || (*c_it >= 0x7f)) {
+                    s.push_back('\\');
+                    s.push_back(0x30 + ((*c_it / 100) % 10));
+                    s.push_back(0x30 + ((*c_it / 10) % 10));
+                    s.push_back(0x30 + (*c_it % 10));
+                    continue;
+                }
+                if ((*c_it == '"') || (*c_it == ';') || (*c_it == '\\')) {
+                    s.push_back('\\');
+                }
+                s.push_back(*c_it);
+            }
             s.push_back('"');
         }
 

src/lib/dns/tests/rdata_txt_like_unittest.cc

@@ -334,6 +334,24 @@ TYPED_TEST(Rdata_TXT_LIKE_Test, toWireRenderer) {
 
 TYPED_TEST(Rdata_TXT_LIKE_Test, toText) {
     EXPECT_EQ("\"Test-String\"", this->rdata_txt_like.toText());
+    EXPECT_EQ("\"\"", this->rdata_txt_like_empty.toText());
+    EXPECT_EQ("\"Test-String\"", this->rdata_txt_like_quoted.toText());
+
+    // Check escape behavior
+    const TypeParam double_quotes("Test-String\"Test-String\"");
+    EXPECT_EQ("\"Test-String\\\"Test-String\\\"\"", double_quotes.toText());
+    const TypeParam semicolon("Test-String\\;Test-String");
+    EXPECT_EQ("\"Test-String\\;Test-String\"", semicolon.toText());
+    const TypeParam backslash("Test-String\\\\Test-String");
+    EXPECT_EQ("\"Test-String\\\\Test-String\"", backslash.toText());
+    const TypeParam before_x20("Test-String\\031Test-String");
+    EXPECT_EQ("\"Test-String\\031Test-String\"", before_x20.toText());
+    const TypeParam from_x20_to_x7e("\"Test-String ~ Test-String\"");
+    EXPECT_EQ("\"Test-String ~ Test-String\"", from_x20_to_x7e.toText());
+    const TypeParam from_x20_to_x7e_2("Test-String\\032\\126\\032Test-String");
+    EXPECT_EQ("\"Test-String ~ Test-String\"", from_x20_to_x7e_2.toText());
+    const TypeParam after_x7e("Test-String\\127Test-String");
+    EXPECT_EQ("\"Test-String\\127Test-String\"", after_x7e.toText());
 }
 
 TYPED_TEST(Rdata_TXT_LIKE_Test, assignment) {