from dataclasses import dataclass from typing import Tuple, Dict import struct import posixpath import os import zlib import gdb def get_file_crc32(filename): with open(filename, "rb") as f: return zlib.crc32(f.read()) @dataclass class AppState: name: str text_address: int = 0 entry_address: int = 0 other_sections: Dict[str, int] = None debug_link_elf: str = "" debug_link_crc: int = 0 def __post_init__(self): if self.other_sections is None: self.other_sections = {} def get_original_elf_path(self, elf_path="build/latest/.extapps") -> str: return ( posixpath.join(elf_path, self.debug_link_elf) if elf_path else self.debug_link_elf ) def is_debug_available(self) -> bool: have_debug_info = bool(self.debug_link_elf and self.debug_link_crc) if not have_debug_info: print("No debug info available for this app") return False debug_elf_path = self.get_original_elf_path() debug_elf_crc32 = get_file_crc32(debug_elf_path) if self.debug_link_crc != debug_elf_crc32: print( f"Debug info ({debug_elf_path}) CRC mismatch: {self.debug_link_crc:08x} != {debug_elf_crc32:08x}, rebuild app" ) return False return True def get_gdb_load_command(self) -> str: load_path = self.get_original_elf_path() print(f"Loading debug information from {load_path}") load_command = ( f"add-symbol-file -readnow {load_path} 0x{self.text_address:08x} " ) load_command += " ".join( f"-s {name} 0x{address:08x}" for name, address in self.other_sections.items() ) return load_command def get_gdb_unload_command(self) -> str: return f"remove-symbol-file -a 0x{self.text_address:08x}" def is_loaded_in_gdb(self, gdb_app) -> bool: # Avoid constructing full app wrapper for comparison return self.entry_address == int(gdb_app["state"]["entry"]) @staticmethod def parse_debug_link_data(section_data: bytes) -> Tuple[str, int]: # Debug link format: a null-terminated string with debuggable file name # Padded with 0's to multiple of 4 bytes # Followed by 4 bytes of CRC32 checksum of that file elf_name = section_data[:-4].decode("utf-8").split("\x00")[0] crc32 = struct.unpack(" "AppState": state = AppState(str(gdb_app["manifest"]["name"].string())) state.entry_address = int(gdb_app["state"]["entry"]) app_state = gdb_app["state"] if debug_link_size := int(app_state["debug_link_info"]["debug_link_size"]): debug_link_data = ( gdb.selected_inferior() .read_memory(int(app_state["debug_link_info"]["debug_link"]), debug_link_size) .tobytes() ) state.debug_link_elf, state.debug_link_crc = AppState.parse_debug_link_data( debug_link_data ) for idx in range(app_state["mmap_entry_count"]): mmap_entry = app_state["mmap_entries"][idx] section_name = mmap_entry["name"].string() section_addr = int(mmap_entry["address"]) if section_name == ".text": state.text_address = section_addr else: state.other_sections[section_name] = section_addr return state class FlipperAppDebugHelper: def __init__(self): self.app_ptr = None self.app_type_ptr = None self.current_app: AppState = None def attach_fw(self) -> None: self.app_ptr = gdb.lookup_global_symbol("last_loaded_app") self.app_type_ptr = gdb.lookup_type("FlipperApplication").pointer() self._check_app_state() def _check_app_state(self) -> None: app_ptr_value = self.app_ptr.value() if not app_ptr_value and self.current_app: # There is an ELF loaded in GDB, but nothing is running on the device self._unload_debug_elf() elif app_ptr_value: # There is an app running on the device loaded_app = app_ptr_value.cast(self.app_type_ptr).dereference() if self.current_app and not self.current_app.is_loaded_in_gdb(loaded_app): # Currently loaded ELF is not the one running on the device self._unload_debug_elf() if not self.current_app: # Load ELF for the app running on the device self._load_debug_elf(loaded_app) def _unload_debug_elf(self) -> None: try: gdb.execute(self.current_app.get_gdb_unload_command()) except gdb.error as e: print(f"Failed to unload debug ELF: {e} (might not be an error)") self.current_app = None def _load_debug_elf(self, app_object) -> None: self.current_app = AppState.from_gdb(app_object) if self.current_app.is_debug_available(): gdb.execute(self.current_app.get_gdb_load_command()) def handle_stop(self, event) -> None: self._check_app_state() helper = FlipperAppDebugHelper() try: helper.attach_fw() print("Support for Flipper external apps debug is enabled") gdb.events.stop.connect(helper.handle_stop) except gdb.error as e: print(f"Support for Flipper external apps debug is not available: {e}")