Fixes and improvements (#616)

Modules/app-module/include/app/metadata.h

@@ -13,6 +13,7 @@ extern "C" {
 #define APP_METADATA_APP_ID_LENGTH 32
 #define APP_METADATA_APP_NAME_LENGTH 32
 #define APP_METADATA_APP_VERSION_NAME_LENGTH 16
+#define APP_METADATA_REQUIRES_DEVICE_ID_LENGTH 64
 
 struct AppMetadata {
 
@@ -42,6 +43,13 @@ struct AppMetadata {
 
     /** The technical version (must be incremented with new releases of the app) */
     uint64_t app_version_code;
+
+    /**
+     * Comma-separated list of device ids the app is restricted to (e.g. "m5stack-tab5"), matching
+     * the folder names under Devices/. Empty means unrestricted.
+     * Must be NULL-terminated.
+     */
+    char requires_device_id[APP_METADATA_REQUIRES_DEVICE_ID_LENGTH + 1];
 };
 
 /**

Modules/app-module/private/app/private/app_metadata_parsing_internal.h

@@ -18,6 +18,9 @@ bool app_metadata_is_valid_name(const std::string& name);
 bool app_metadata_is_valid_version_name(const std::string& version);
 bool app_metadata_is_valid_version_code(const std::string& version);
 
+/** Validates a comma-separated list of device ids (alphanumeric + '-' items, matching Devices/<id> folder names). */
+bool app_metadata_is_valid_device_id_list(const std::string& value);
+
 /** Copies @a value into @a dest (a fixed-size buffer of @a dest_size bytes, including the NULL
  * terminator) if it fits.
  * @retval false @a value doesn't fit in @a dest_size bytes - @a dest is left untouched */

Modules/app-module/source/app_metadata_parsing.cpp

@@ -37,6 +37,26 @@ bool validate_string(const std::string& value, bool (*is_valid_char)(char)) {
     return true;
 }
 
+/** Validates a comma-separated list: non-empty, no leading/trailing/double commas (which would
+ * produce an empty item), and every item passing @a is_valid_item. */
+bool validate_csv_list(const std::string& value, bool (*is_valid_item)(const std::string&)) {
+    if (value.empty()) {
+        return false;
+    }
+    size_t start = 0;
+    while (true) {
+        auto comma = value.find(',', start);
+        auto end = comma == std::string::npos ? value.size() : comma;
+        if (end == start || !is_valid_item(value.substr(start, end - start))) {
+            return false;
+        }
+        if (comma == std::string::npos) {
+            return true;
+        }
+        start = comma + 1;
+    }
+}
+
 /** manifest.properties format: "key=value" lines, "[section]" lines prefix every following key
  * until the next section, "#" lines are comments, blank lines are skipped. Deliberately a local,
  * minimal re-implementation rather than depending on Tactility's file::loadPropertiesFile() -
@@ -130,6 +150,20 @@ bool app_metadata_is_valid_version_code(const std::string& version) {
     });
 }
 
+bool app_metadata_is_valid_device_id_list(const std::string& value) {
+    return validate_csv_list(value, [](const std::string& item) {
+        bool has_alnum = false;
+        for (char c: item) {
+            if (std::isalnum(static_cast<unsigned char>(c)) != 0) {
+                has_alnum = true;
+            } else if (c != '-') {
+                return false;
+            }
+        }
+        return has_alnum;
+    });
+}
+
 bool app_metadata_copy_bounded(char* dest, size_t dest_size, const std::string& value) {
     if (value.size() >= dest_size) {
         return false;
@@ -141,6 +175,10 @@ bool app_metadata_copy_bounded(char* dest, size_t dest_size, const std::string&
 error_t app_metadata_parse(const char* path, struct AppMetadata* out_metadata) {
     LOG_I(TAG, "Parsing manifest %s", path);
 
+    // requires_device_id is optional in V2 and unwritten by V1; zeroing here (rather than relying
+    // on the caller) guarantees it reads back as empty ("unrestricted") either way.
+    *out_metadata = {};
+
     std::map<std::string, std::string> properties;
     std::string first_line;
     if (!load_properties(path, properties, first_line)) {

Modules/app-module/source/app_metadata_parsing_v2.cpp

@@ -99,5 +99,20 @@ bool app_metadata_parse_v2(const std::map<std::string, std::string>& properties,
         return false;
     }
 
+    // requires.device.id (optional; if present, must be a non-empty comma-separated list)
+
+    auto device_id_iterator = properties.find("requires.device.id");
+    if (device_id_iterator != properties.end()) {
+        const std::string& device_id = device_id_iterator->second;
+        if (!app_metadata_is_valid_device_id_list(device_id)) {
+            LOG_E(TAG, "Invalid requires.device.id");
+            return false;
+        }
+        if (!app_metadata_copy_bounded(out_metadata.requires_device_id, sizeof(out_metadata.requires_device_id), device_id)) {
+            LOG_E(TAG, "requires.device.id too long");
+            return false;
+        }
+    }
+
     return true;
 }

Modules/app-module/source/app_paths.cpp

@@ -13,7 +13,7 @@ error_t app_paths_get_user_data_directory(const char* app_id, char* out_path, si
     if (error != ERROR_NONE) {
         return error;
     }
-    int written = std::snprintf(out_path, out_path_size, "%s/app/%s", root, app_id);
+    int written = std::snprintf(out_path, out_path_size, "%s/user/app/%s", root, app_id);
     if (written < 0 || (size_t)written >= out_path_size) {
         return ERROR_BUFFER_OVERFLOW;
     }