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[FL-3161] Improved debugging experience for external apps (#2507)

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* debug: automated support for multiple debug symbol files
* faploader: extra checks for app list state
* debug: trigger BP before fap's EP if under debugger
* faploader, debug: better naming
* docs: info on load breakpoint
* faploader: header cleanup
* faploader: naming fixes
* debug: less verbose; setting debug flag more often
* typo fix
This commit is contained in:
hedger
2023-03-20 19:03:55 +04:00
committed by GitHub
parent f7024cff78
commit 60ac2e9881
5 changed files with 127 additions and 59 deletions
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113
debug/flipperapps.py
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@@ -2,7 +2,6 @@ from dataclasses import dataclass
from typing import Optional, Tuple, Dict, ClassVar
import struct
import posixpath
import os
import zlib
import gdb
@@ -66,9 +65,9 @@ class AppState:
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 get_gdb_app_ep(app) -> int:
return int(app["state"]["entry"])
@staticmethod
def parse_debug_link_data(section_data: bytes) -> Tuple[str, int]:
@@ -79,10 +78,10 @@ class AppState:
crc32 = struct.unpack("<I", section_data[-4:])[0]
return (elf_name, crc32)
@staticmethod
def from_gdb(gdb_app: "AppState") -> "AppState":
@classmethod
def from_gdb(cls, gdb_app: "AppState") -> "AppState":
state = AppState(str(gdb_app["manifest"]["name"].string()))
state.entry_address = int(gdb_app["state"]["entry"])
state.entry_address = cls.get_gdb_app_ep(gdb_app)
app_state = gdb_app["state"]
if debug_link_size := int(app_state["debug_link_info"]["debug_link_size"]):
@@ -123,59 +122,83 @@ class SetFapDebugElfRoot(gdb.Command):
try:
global helper
print(f"Set '{arg}' as debug info lookup path for Flipper external apps")
helper.attach_fw()
helper.attach_to_fw()
gdb.events.stop.connect(helper.handle_stop)
gdb.events.exited.connect(helper.handle_exit)
except gdb.error as e:
print(f"Support for Flipper external apps debug is not available: {e}")
SetFapDebugElfRoot()
class FlipperAppDebugHelper:
class FlipperAppStateHelper:
def __init__(self):
self.app_ptr = None
self.app_type_ptr = None
self.current_app: AppState = None
self.app_list_ptr = None
self.app_list_entry_type = None
self._current_apps: list[AppState] = []
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 _walk_app_list(self, list_head):
while list_head:
if app := list_head["data"]:
yield app.dereference()
list_head = list_head["next"]
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:
def _exec_gdb_command(self, command: str) -> bool:
try:
gdb.execute(self.current_app.get_gdb_unload_command())
gdb.execute(command)
return True
except gdb.error as e:
print(f"Failed to unload debug ELF: {e} (might not be an error)")
self.current_app = None
print(f"Failed to execute GDB command '{command}': {e}")
return False
def _load_debug_elf(self, app_object) -> None:
self.current_app = AppState.from_gdb(app_object)
def _sync_apps(self) -> None:
self.set_debug_mode(True)
if not (app_list := self.app_list_ptr.value()):
print("Reset app loader state")
for app in self._current_apps:
self._exec_gdb_command(app.get_gdb_unload_command())
self._current_apps = []
return
if self.current_app.is_debug_available():
gdb.execute(self.current_app.get_gdb_load_command())
loaded_apps: dict[int, gdb.Value] = dict(
(AppState.get_gdb_app_ep(app), app)
for app in self._walk_app_list(app_list[0])
)
for app in self._current_apps.copy():
if app.entry_address not in loaded_apps:
print(f"Application {app.name} is no longer loaded")
if not self._exec_gdb_command(app.get_gdb_unload_command()):
print(f"Failed to unload debug info for {app.name}")
self._current_apps.remove(app)
for entry_point, app in loaded_apps.items():
if entry_point not in set(app.entry_address for app in self._current_apps):
new_app_state = AppState.from_gdb(app)
print(f"New application loaded. Adding debug info")
if self._exec_gdb_command(new_app_state.get_gdb_load_command()):
self._current_apps.append(new_app_state)
else:
print(f"Failed to load debug info for {new_app_state}")
def attach_to_fw(self) -> None:
print("Attaching to Flipper firmware")
self.app_list_ptr = gdb.lookup_global_symbol(
"flipper_application_loaded_app_list"
)
self.app_type_ptr = gdb.lookup_type("FlipperApplication").pointer()
self.app_list_entry_type = gdb.lookup_type("struct FlipperApplicationList_s")
def handle_stop(self, event) -> None:
self._check_app_state()
self._sync_apps()
def handle_exit(self, event) -> None:
self.set_debug_mode(False)
def set_debug_mode(self, mode: bool) -> None:
gdb.execute(f"set variable fap_loader_debug_active = {int(mode)}")
helper = FlipperAppDebugHelper()
# Init additional 'fap-set-debug-elf-root' command and set up hooks
SetFapDebugElfRoot()
helper = FlipperAppStateHelper()
print("Support for Flipper external apps debug is loaded")