ams_mitm: implement layeredfs

stratosphere/ams_mitm/source/amsmitm_fs_utils.cpp

@@ -19,6 +19,8 @@
 
 namespace ams::mitm::fs {
 
+    using namespace ams::fs;
+
     namespace {
 
         /* Globals. */
@@ -46,6 +48,18 @@ namespace ams::mitm::fs {
             }
         }
 
+        void FormatAtmosphereSdPath(char *dst_path, size_t dst_path_size, ncm::ProgramId program_id, const char *subdir, const char *src_path) {
+            if (src_path[0] == '/') {
+                std::snprintf(dst_path, dst_path_size, "/atmosphere/contents/%016lx/%s%s", static_cast<u64>(program_id), subdir, src_path);
+            } else {
+                std::snprintf(dst_path, dst_path_size, "/atmosphere/contents/%016lx/%s/%s", static_cast<u64>(program_id), subdir, src_path);
+            }
+        }
+
+        void FormatAtmosphereRomfsPath(char *dst_path, size_t dst_path_size, ncm::ProgramId program_id, const char *src_path) {
+            return FormatAtmosphereSdPath(dst_path, dst_path_size, program_id, "romfs", src_path);
+        }
+
     }
 
     void OpenGlobalSdCardFileSystem() {
@@ -69,4 +83,95 @@ namespace ams::mitm::fs {
         return OpenSdFile(out, fixed_path, mode);
     }
 
+    Result OpenAtmosphereSdRomfsFile(FsFile *out, ncm::ProgramId program_id, const char *path, u32 mode) {
+        char fixed_path[FS_MAX_PATH];
+        FormatAtmosphereRomfsPath(fixed_path, sizeof(fixed_path), program_id, path);
+        return OpenSdFile(out, fixed_path, mode);
+    }
+
+    Result OpenAtmosphereRomfsFile(FsFile *out, ncm::ProgramId program_id, const char *path, u32 mode, FsFileSystem *fs) {
+        char fixed_path[FS_MAX_PATH];
+        FormatAtmosphereRomfsPath(fixed_path, sizeof(fixed_path), program_id, path);
+        return fsFsOpenFile(fs, fixed_path, mode, out);
+    }
+
+    Result OpenSdDirectory(FsDir *out, const char *path, u32 mode) {
+        R_TRY(EnsureSdInitialized());
+        return fsFsOpenDirectory(&g_sd_filesystem, path, mode, out);
+    }
+
+    Result OpenAtmosphereSdDirectory(FsDir *out, const char *path, u32 mode) {
+        char fixed_path[FS_MAX_PATH];
+        FormatAtmosphereSdPath(fixed_path, sizeof(fixed_path), path);
+        return OpenSdDirectory(out, fixed_path, mode);
+    }
+
+    Result OpenAtmosphereSdDirectory(FsDir *out, ncm::ProgramId program_id, const char *path, u32 mode) {
+        char fixed_path[FS_MAX_PATH];
+        FormatAtmosphereSdPath(fixed_path, sizeof(fixed_path), program_id, path);
+        return OpenSdDirectory(out, fixed_path, mode);
+    }
+
+    Result OpenAtmosphereSdRomfsDirectory(FsDir *out, ncm::ProgramId program_id, const char *path, u32 mode) {
+        char fixed_path[FS_MAX_PATH];
+        FormatAtmosphereRomfsPath(fixed_path, sizeof(fixed_path), program_id, path);
+        return OpenSdDirectory(out, fixed_path, mode);
+    }
+
+    Result OpenAtmosphereRomfsDirectory(FsDir *out, ncm::ProgramId program_id, const char *path, u32 mode, FsFileSystem *fs) {
+        char fixed_path[FS_MAX_PATH];
+        FormatAtmosphereRomfsPath(fixed_path, sizeof(fixed_path), program_id, path);
+        return fsFsOpenDirectory(fs, fixed_path, mode, out);
+    }
+
+
+    bool HasSdRomfsContent(ncm::ProgramId program_id) {
+        /* Check if romfs.bin is present. */
+        {
+            FsFile romfs_file;
+            if (R_SUCCEEDED(OpenAtmosphereSdFile(&romfs_file, program_id, "romfs.bin", OpenMode_Read))) {
+                fsFileClose(&romfs_file);
+                return true;
+            }
+        }
+
+        /* Check for romfs folder with content. */
+        FsDir romfs_dir;
+        if (R_FAILED(OpenAtmosphereSdRomfsDirectory(&romfs_dir, program_id, "", OpenDirectoryMode_All))) {
+            return false;
+        }
+        ON_SCOPE_EXIT { fsDirClose(&romfs_dir); };
+
+        /* Verify the folder has at least one entry. */
+        s64 num_entries = 0;
+        return R_SUCCEEDED(fsDirGetEntryCount(&romfs_dir, &num_entries)) && num_entries > 0;
+    }
+
+    Result SaveAtmosphereSdFile(FsFile *out, ncm::ProgramId program_id, const char *path, void *data, size_t size) {
+        R_TRY(EnsureSdInitialized());
+
+        char fixed_path[FS_MAX_PATH];
+        FormatAtmosphereSdPath(fixed_path, sizeof(fixed_path), program_id, path);
+
+        /* Unconditionally create. */
+        /* Don't check error, as a failure here should be okay. */
+        FsFile f;
+        fsFsCreateFile(&g_sd_filesystem, fixed_path, size, 0);
+
+        /* Try to open. */
+        R_TRY(fsFsOpenFile(&g_sd_filesystem, fixed_path, OpenMode_ReadWrite, &f));
+        auto file_guard = SCOPE_GUARD { fsFileClose(&f); };
+
+        /* Try to set the size. */
+        R_TRY(fsFileSetSize(&f, static_cast<s64>(size)));
+
+        /* Try to write data. */
+        R_TRY(fsFileWrite(&f, 0, data, size, FsWriteOption_Flush));
+
+        /* Set output. */
+        file_guard.Cancel();
+        *out = f;
+        return ResultSuccess();
+    }
+
 }