Python-for-android: socket.getaddrinfo appears to be completely broken, all name resolutions fail

[etc0de]

Versions

• Python: python3crystax (app), python 3 on host for building
• OS: Ubuntu in docker for building, android 7 for test
• Kivy: not used
• Cython: most likely not relevant (can check if it is)

Description

Name resolution with socket.getaddrinfo just seems to plain not work, here is what I get for google.com (while nslookup google.com in termux or just browsing google.com in the web browser works fine):

11-07 03:17:28.760 30786 30818 I python  : Traceback (most recent call last):
11-07 03:17:28.760 30786 30818 I python  :   File "/mnt/expand/50b713c2-bef0-4226-aea1-000678d55d07/user/0/com.example.app/files/app/crystax_python/site-packages/nettools/__init__.py", line 59, in dns_lookup_multitarget
11-07 03:17:28.761 30786 30818 I python  :     name, None, socket.AF_INET6)
11-07 03:17:28.761 30786 30818 I python  :   File "/mnt/expand/50b713c2-bef0-4226-aea1-000678d55d07/user/0/com.example.app/files/app/crystax_python/stdlib.zip/socket.py", line 743, in getaddrinfo
11-07 03:17:28.761 30786 30818 I python  :     for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
11-07 03:17:28.761 30786 30818 I python  : socket.gaierror: [Errno 7] No address associated with hostname
11-07 03:17:28.761 30786 30818 I python  : 
11-07 03:17:28.761 30786 30818 I python  : During handling of the above exception, another exception occurred:
11-07 03:17:28.761 30786 30818 I python  : 
11-07 03:17:28.761 30786 30818 I python  : Traceback (most recent call last):
11-07 03:17:28.761 30786 30818 I python  :   File "<console>", line 1, in <module>
11-07 03:17:28.761 30786 30818 I python  :   File "/mnt/expand/50b713c2-bef0-4226-aea1-000678d55d07/user/0/com.example.app/files/app/crystax_python/site-packages/nettools/__init__.py", line 78, in dns_lookup
11-07 03:17:28.761 30786 30818 I python  :     raise last_error
11-07 03:17:28.762 30786 30818 I python  :   File "/mnt/expand/50b713c2-bef0-4226-aea1-000678d55d07/user/0/com.example.app/files/app/crystax_python/site-packages/nettools/__init__.py", line 66, in dns_lookup_multitarget
11-07 03:17:28.762 30786 30818 I python  :     name, None, socket.AF_INET)
11-07 03:17:28.762 30786 30818 I python  :   File "/mnt/expand/50b713c2-bef0-4226-aea1-000678d55d07/user/0/com.example.app/files/app/crystax_python/stdlib.zip/socket.py", line 743, in getaddrinfo
11-07 03:17:28.762 30786 30818 I python  :     for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
11-07 03:17:28.762 30786 30818 I python  : socket.gaierror: [Errno 7] No address associated with hostname

The same code works fine on desktop (with python 3 on GNU/Linux and Microsoft Windows). Please note I wrote nettools so I'm not using some odd third-party wrapper that may do whatever instead of just looking up the hostname - all the function I wrote does is automatically try AF_INET6 first and fall back to AF_INET if that doesn't work (as should be easy to reconstruct from the backtrace).

I tested this on latest master with the ctypes fix pull request on top ( #1433 ) which shouldn't affect name resolution.

buildozer.spec

not used, I build with a p4a one liner

Logs

see backtrace above

[etc0de]

I forgot I have an interactive debug console in my app, where I tried this:

import socket; socket.getaddrinfo("google.com", None, socket.AF_INET)

This is the result:

11-07 03:26:16.767 30786 30818 I python  : Traceback (most recent call last):
11-07 03:26:16.767 30786 30818 I python  :   File "<console>", line 1, in <module>
11-07 03:26:16.767 30786 30818 I python  :   File "/mnt/expand/50b713c2-bef0-4226-aea1-000678d55d07/user/0/com.example.app/files/app/crystax_python/stdlib.zip/socket.py", line 743, in getaddrinfo
11-07 03:26:16.768 30786 30818 I python  :     for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
11-07 03:26:16.768 30786 30818 I python  : socket.gaierror: [Errno 7] No address associated with hostname

WIth my desktop python, it works (try for yourself if you're curious):

$ python3
Python 3.6.6 (default, Jul 19 2018, 14:25:17) 
[GCC 8.1.1 20180712 (Red Hat 8.1.1-5)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import socket; socket.getaddrinfo("google.com", None, socket.AF_INET)
[(<AddressFamily.AF_INET: 2>, <SocketKind.SOCK_STREAM: 1>, 6, '', ('172.217.22.14', 0)), (<AddressFamily.AF_INET: 2>, <SocketKind.SOCK_DGRAM: 2>, 17, '', ('172.217.22.14', 0)), (<AddressFamily.AF_INET: 2>, <SocketKind.SOCK_RAW: 3>, 0, '', ('172.217.22.14', 0))]

Edit: I just tested, socket.gethostbyname gives the same error. How does name resolution work for any of you guys on Android?? Wondering if I'm doing something very obviously wrong...

[etc0de]

Is there anyone for whom socket.gesthostbyname works with latest p4a master and python3crystax? I'm kind of poking in the dark here

[etc0de]

Well, I assumed since Android never prompts for an "internet" permission in recent versions that it wasn't needed :rofl: so yeah... still busy building a new test version but I assume that's the culprit. (Will close tickets in a few minutes once I confirmed with the new test build)

[etc0de]

:laughing: yup, was internet permission

[Adistar964]

how to give android internet permissions(I gave it, but it does not show up)