“unable to inject library into process without libc” when attach to child process that origin=exec

[caozhzh]

this is my environment: genymotion: 3.2.1 + Samsung Galaxy S7 6.0-API 23,also test on Google Nexus 5X 8.0-API 26 frida-server: frida-server-15.1.17-android-x86,also tested frida-server-15.1.14-android-x86 and frida-server-15.0.0-android-x86 script: https://github.com/frida/frida-python/blob/master/examples/child_gating.py I only changed the argv to myappid def _start(self): argv = [myappid]

and I got these outputs:

✔ spawn(argv=['myappid']) ✔ attach(pid=4486) ✔ enable_child_gating() ✔ create_script() ✔ resume(pid=4486) ⚡ child_added: Child(pid=4602, parent_pid=4486, origin=fork) ✔ attach(pid=4602) ✔ enable_child_gating() ✔ create_script() ✔ resume(pid=4602) ⚡ child_removed: Child(pid=4602, parent_pid=4486, origin=fork) ⚡ child_added: Child(pid=4602, parent_pid=4602, origin=exec, ......) ✔ attach(pid=4602) Exception in thread Thread-1: Traceback (most recent call last): File "/home/nothing/miniconda3/lib/python3.7/threading.py", line 926, in _bootstrap_inner self.run() File "/home/nothing/miniconda3/lib/python3.7/threading.py", line 870, in run self._target(*self._args, **self._kwargs) File "/home/nothing/miniconda3/lib/python3.7/site-packages/frida_tools/application.py", line 765, in _run work() File "lavpn.usa_spawn_gating.py", line 20, in self._device.on("child-added", lambda child: self._reactor.schedule(lambda: self._on_child_added(child))) File "lavpn.usa_spawn_gating.py", line 61, in _on_child_added self._instrument(child.pid, child) File "lavpn.usa_spawn_gating.py", line 45, in _instrument session = self._device.attach(pid) File "/home/nothing/miniconda3/lib/python3.7/site-packages/frida/core.py", line 26, in wrapper return f(*args, **kwargs) File "/home/nothing/miniconda3/lib/python3.7/site-packages/frida/core.py", line 165, in attach return Session(self._impl.attach(self._pid_of(target), *args, **kwargs)) frida.NotSupportedError: unable to inject library into process without libc

We can see that when attach the child process which origin is fork,it's ok. but when attach the same process which origin changed to exec,the error occurs. I searched and find https://github.com/frida/frida/issues/936,but no lucky. I think maybe because I used genymotion emulator, but why first attach is ok?