dns.mitm: support % in hosts file as stand-in for environment identifier

libraries/libstratosphere/source/nsd/impl/device/nsd_device.cpp

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+
+namespace ams::nsd::impl::device {
+
+    namespace {
+
+        constexpr const char SettingsName[] = "nsd";
+        constexpr const char SettingsKey[]  = "environment_identifier";
+
+        constinit os::SdkMutex g_environment_identifier_lock;
+        constinit EnvironmentIdentifier g_environment_identifier = {};
+        constinit bool g_determined_environment_identifier = false;
+
+    }
+
+    const EnvironmentIdentifier &GetEnvironmentIdentifierFromSettings() {
+        std::scoped_lock lk(g_environment_identifier_lock);
+
+        if (!g_determined_environment_identifier) {
+            /* Check size. */
+            AMS_ABORT_UNLESS(settings::fwdbg::GetSettingsItemValueSize(SettingsName, SettingsKey) != 0);
+
+            /* Get value. */
+            const size_t size = settings::fwdbg::GetSettingsItemValue(g_environment_identifier.value, EnvironmentIdentifier::Size, SettingsName, SettingsKey);
+            AMS_ABORT_UNLESS(size < EnvironmentIdentifier::Size);
+            AMS_ABORT_UNLESS(g_environment_identifier == EnvironmentIdentifierOfProductDevice || g_environment_identifier == EnvironmentIdentifierOfNotProductDevice);
+
+            g_determined_environment_identifier = true;
+        }
+
+        return g_environment_identifier;
+    }
+
+}