git subrepo clone https://github.com/Atmosphere-NX/libstratosphere stratosphere/libstratosphere

subrepo:
  subdir:   "stratosphere/libstratosphere"
  merged:   "0c5dab80"
upstream:
  origin:   "https://github.com/Atmosphere-NX/libstratosphere"
  branch:   "master"
  commit:   "0c5dab80"
git-subrepo:
  version:  "0.4.0"
  origin:   "https://github.com/ingydotnet/git-subrepo"
  commit:   "5d6aba9"

stratosphere/libstratosphere/source/cfg/cfg_flags.cpp

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2018-2019 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 <switch.h>
+#include <stratosphere.hpp>
+#include <stratosphere/cfg.hpp>
+
+namespace sts::cfg {
+
+    namespace {
+
+        /* Helper. */
+        bool HasFlagFile(const char *flag_path) {
+            /* All flags are not present until the SD card is. */
+            if (!IsSdCardInitialized()) {
+                return false;
+            }
+
+            /* Mount the SD card. */
+            FsFileSystem sd_fs = {};
+            if (R_FAILED(fsMountSdcard(&sd_fs))) {
+                return false;
+            }
+            ON_SCOPE_EXIT { serviceClose(&sd_fs.s); };
+
+            /* Open the file. */
+            FsFile flag_file;
+            if (R_FAILED(fsFsOpenFile(&sd_fs, flag_path, FS_OPEN_READ, &flag_file))) {
+                return false;
+            }
+            fsFileClose(&flag_file);
+
+            return true;
+        }
+
+    }
+
+    /* Flag utilities. */
+    bool HasFlag(ncm::TitleId title_id, const char *flag) {
+        return HasTitleSpecificFlag(title_id, flag) || (IsHblTitleId(title_id) && HasHblFlag(flag));
+    }
+
+    bool HasTitleSpecificFlag(ncm::TitleId title_id, const char *flag) {
+        char title_flag[FS_MAX_PATH];
+        std::snprintf(title_flag, sizeof(title_flag) - 1, "/atmosphere/titles/%016lx/flags/%s.flag", static_cast<u64>(title_id), flag);
+        return HasFlagFile(title_flag);
+    }
+
+    bool HasGlobalFlag(const char *flag) {
+        char title_flag[FS_MAX_PATH];
+        std::snprintf(title_flag, sizeof(title_flag) - 1, "/atmosphere/flags/%s.flag", flag);
+        return HasFlagFile(title_flag);
+    }
+
+    bool HasHblFlag(const char *flag) {
+        char hbl_flag[0x100];
+        std::snprintf(hbl_flag, sizeof(hbl_flag) - 1, "hbl_%s", flag);
+        return HasGlobalFlag(hbl_flag);
+    }
+
+}