git subrepo clone https://github.com/Atmosphere-NX/Atmosphere-libs libraries

subrepo:
  subdir:   "libraries"
  merged:   "07af583b"
upstream:
  origin:   "https://github.com/Atmosphere-NX/Atmosphere-libs"
  branch:   "master"
  commit:   "07af583b"
git-subrepo:
  version:  "0.4.0"
  origin:   "https://github.com/ingydotnet/git-subrepo"
  commit:   "5d6aba9"

libraries/libstratosphere/source/ams/ams_emummc_api.cpp

@@ -0,0 +1,137 @@
+/*
+ * 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 <stratosphere.hpp>
+
+namespace ams::emummc {
+
+    namespace {
+
+        /* Convenience Definitions. */
+        constexpr u32 StorageMagic = 0x30534645; /* EFS0 */
+        constexpr size_t MaxDirLen = 0x7F;
+
+        /* Types. */
+        struct BaseConfig {
+            u32 magic;
+            u32 type;
+            u32 id;
+            u32 fs_version;
+        };
+
+        struct PartitionConfig {
+            u64 start_sector;
+        };
+
+        struct FileConfig {
+            char path[MaxDirLen + 1];
+        };
+
+        struct ExosphereConfig {
+            BaseConfig base_cfg;
+            union {
+                PartitionConfig partition_cfg;
+                FileConfig file_cfg;
+            };
+            char emu_dir_path[MaxDirLen + 1];
+        };
+
+        enum Storage : u32 {
+            Storage_Emmc,
+            Storage_Sd,
+            Storage_SdFile,
+
+            Storage_Count,
+        };
+
+        /* Globals. */
+        os::Mutex g_lock;
+        ExosphereConfig g_exo_config;
+        bool g_is_emummc;
+        bool g_has_cached;
+
+        /* Helpers. */
+        void CacheValues() {
+            std::scoped_lock lk(g_lock);
+
+            if (g_has_cached) {
+                return;
+            }
+
+            /* Retrieve and cache values. */
+            {
+
+                typename std::aligned_storage<2 * (MaxDirLen + 1), os::MemoryPageSize>::type path_storage;
+
+                struct {
+                    char file_path[MaxDirLen + 1];
+                    char nintendo_path[MaxDirLen + 1];
+                } *paths = reinterpret_cast<decltype(paths)>(&path_storage);
+
+                /* Retrieve paths from secure monitor. */
+                AMS_ASSERT(spl::smc::AtmosphereGetEmummcConfig(&g_exo_config, paths, 0) == spl::smc::Result::Success);
+
+                const Storage storage = static_cast<Storage>(g_exo_config.base_cfg.type);
+                g_is_emummc = g_exo_config.base_cfg.magic == StorageMagic && storage != Storage_Emmc;
+
+                /* Format paths. Ignore string format warnings. */
+                #pragma GCC diagnostic push
+                #pragma GCC diagnostic ignored "-Wformat-truncation"
+                {
+                    if (storage == Storage_SdFile) {
+                        std::snprintf(g_exo_config.file_cfg.path, sizeof(g_exo_config.file_cfg.path), "/%s", paths->file_path);
+                    }
+
+                    std::snprintf(g_exo_config.emu_dir_path, sizeof(g_exo_config.emu_dir_path), "/%s", paths->nintendo_path);
+
+                    /* If we're emummc, implement default nintendo redirection path. */
+                    if (g_is_emummc && std::strcmp(g_exo_config.emu_dir_path, "/") == 0) {
+                        std::snprintf(g_exo_config.emu_dir_path, sizeof(g_exo_config.emu_dir_path), "/emummc/Nintendo_%04x", g_exo_config.base_cfg.id);
+                    }
+                }
+                #pragma GCC diagnostic pop
+            }
+
+            g_has_cached = true;
+        }
+
+    }
+
+    /* Get whether emummc is active. */
+    bool IsActive() {
+        CacheValues();
+        return g_is_emummc;
+    }
+
+    /* Get Nintendo redirection path. */
+    const char *GetNintendoDirPath() {
+        CacheValues();
+        if (!g_is_emummc) {
+            return nullptr;
+        }
+        return g_exo_config.emu_dir_path;
+    }
+
+    /* Get Emummc folderpath, NULL if not file-based. */
+    const char *GetFilePath() {
+        CacheValues();
+        if (!g_is_emummc || g_exo_config.base_cfg.type != Storage_SdFile) {
+            return nullptr;
+        }
+        return g_exo_config.file_cfg.path;
+    }
+
+}