Refactor how test RNG is created

1 files changed, 82 insertions, 81 deletions

diff --git a/src/tests/main.cpp b/src/tests/main.cpp
index 891f71304..0ddd28dc2 100644
--- a/src/tests/main.cpp
+++ b/src/tests/main.cpp
@@ -47,6 +47,87 @@ class Test_Runner final : public Botan_CLI::Command
          : Command("test --threads=0 --run-long-tests --run-online-tests --test-runs=1 --drbg-seed= --data-dir="
                    " --pkcs11-lib= --provider= --log-success *suites") {}
 
+      std::unique_ptr<Botan::RandomNumberGenerator>
+      create_test_rng(const std::string& drbg_seed)
+         {
+         std::unique_ptr<Botan::RandomNumberGenerator> rng;
+
+#if defined(BOTAN_HAS_HMAC_DRBG) && defined(BOTAN_HAS_SHA2_64)
+
+         std::vector<uint8_t> seed = Botan::hex_decode(drbg_seed);
+         if(seed.empty())
+            {
+            const uint64_t ts = Botan_Tests::Test::timestamp();
+            seed.resize(8);
+            Botan::store_be(ts, seed.data());
+            }
+
+         output() << " rng:HMAC_DRBG with seed '" << Botan::hex_encode(seed) << "'\n";
+
+         // Expand out the seed to 512 bits to make the DRBG happy
+         std::unique_ptr<Botan::HashFunction> sha512(Botan::HashFunction::create("SHA-512"));
+         sha512->update(seed);
+         seed.resize(sha512->output_length());
+         sha512->final(seed.data());
+
+         std::unique_ptr<Botan::HMAC_DRBG> drbg(new Botan::HMAC_DRBG("SHA-384"));
+         drbg->initialize_with(seed.data(), seed.size());
+
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
+         rng.reset(new Botan::Serialized_RNG(drbg.release()));
+#else
+         rng = std::move(drbg);
+#endif
+
+#endif
+
+         if(!rng && drbg_seed != "")
+            throw Botan_Tests::Test_Error("HMAC_DRBG disabled in build, cannot specify DRBG seed");
+
+#if defined(BOTAN_HAS_SYSTEM_RNG)
+         if(!rng)
+            {
+            output() << " rng:system\n";
+            rng.reset(new Botan::System_RNG);
+            }
+#endif
+
+#if defined(BOTAN_HAS_AUTO_SEEDING_RNG)
+         if(!rng)
+            {
+            output() << " rng:autoseeded\n";
+            rng.reset(new Botan::Serialized_RNG(new Botan::AutoSeeded_RNG));
+            }
+#endif
+
+         if(!rng)
+            {
+            // last ditch fallback for RNG-less build
+            class Bogus_Fallback_RNG final : public Botan::RandomNumberGenerator
+               {
+               public:
+                  std::string name() const override { return "Bogus_Fallback_RNG"; }
+
+                  void clear() override { /* ignored */ }
+                  void add_entropy(const uint8_t[], size_t) override { /* ignored */ }
+                  bool is_seeded() const override { return true; }
+
+                  void randomize(uint8_t out[], size_t len) override
+                     {
+                     for(size_t i = 0; i != len; ++i)
+                        {
+                        out[i] = std::rand();
+                        }
+                     }
+               };
+
+            output() << " rng:bogus\n";
+            rng.reset(new Bogus_Fallback_RNG);
+            }
+
+         return rng;
+         }
+
       std::string help_text() const override
          {
          std::ostringstream err;
@@ -174,87 +255,7 @@ class Test_Runner final : public Botan_CLI::Command
             }
 #endif
 
-         std::unique_ptr<Botan::RandomNumberGenerator> rng;
-
-#if defined(BOTAN_HAS_HMAC_DRBG) && defined(BOTAN_HAS_SHA2_64)
-         std::vector<uint8_t> seed = Botan::hex_decode(drbg_seed);
-         if(seed.empty())
-            {
-            const uint64_t ts = Botan_Tests::Test::timestamp();
-            seed.resize(8);
-            Botan::store_be(ts, seed.data());
-            }
-
-         output() << " rng:HMAC_DRBG with seed '" << Botan::hex_encode(seed) << "'";
-
-         // Expand out the seed to 512 bits to make the DRBG happy
-         std::unique_ptr<Botan::HashFunction> sha512(Botan::HashFunction::create("SHA-512"));
-         sha512->update(seed);
-         seed.resize(sha512->output_length());
-         sha512->final(seed.data());
-
-         std::unique_ptr<Botan::HMAC_DRBG> drbg(new Botan::HMAC_DRBG("SHA-384"));
-         drbg->initialize_with(seed.data(), seed.size());
-
-#if defined(BOTAN_TARGET_OS_HAS_THREADS)
-         rng.reset(new Botan::Serialized_RNG(drbg.release()));
-#else
-         rng = std::move(drbg);
-#endif
-
-#else
-
-         if(drbg_seed != "")
-            {
-            throw Botan_Tests::Test_Error("HMAC_DRBG disabled in build, cannot specify DRBG seed");
-            }
-
-#if defined(BOTAN_HAS_SYSTEM_RNG)
-         output() << " rng:system";
-         rng.reset(new Botan::System_RNG);
-#elif defined(BOTAN_HAS_AUTO_SEEDING_RNG)
-         output() << " rng:autoseeded";
-         rng.reset(new Botan::Serialized_RNG(new Botan::AutoSeeded_RNG));
-#else
-         // last ditch fallback for RNG-less build
-         class Bogus_Fallback_RNG final : public Botan::RandomNumberGenerator
-            {
-            public:
-               std::string name() const override
-                  {
-                  return "Bogus_Fallback_RNG";
-                  }
-
-               void clear() override
-                  {
-                  /* ignored */
-                  }
-
-               void randomize(uint8_t out[], size_t len) override
-                  {
-                  for(size_t i = 0; i != len; ++i)
-                     {
-                     out[i] = std::rand();
-                     }
-                  }
-
-               bool is_seeded() const override
-                  {
-                  return true;
-                  }
-
-               void add_entropy(const uint8_t[], size_t) override
-                  {
-                  /* ignored */
-                  }
-            };
-
-         rng.reset(new Bogus_Fallback_RNG);
-#endif
-
-#endif
-
-         output() << "\n";
+         std::unique_ptr<Botan::RandomNumberGenerator> rng = create_test_rng(drbg_seed);
 
          Botan_Tests::Test::setup_tests(log_success, run_online_tests, run_long_tests,
                                         data_dir, pkcs11_lib, pf, rng.get());