When binding a unix socket to an empty address on Linux, the socket is
automatically bound to an available address in the abstract namespace.
>>> s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
>>> s.bind("")
>>> s.getsockname()
b'\x0075499'
Since python 3.9, the socket is bound to the one address:
>>> s.getsockname()
b'\x00'
And trying to bind multiple sockets will fail with:
Traceback (most recent call last):
File "/home/nsoffer/src/cpython/Lib/test/test_socket.py", line 5553, in testAutobind
s2.bind("")
OSError: [Errno 98] Address already in use
Added 2 tests:
- Auto binding empty address on Linux
- Failing to bind an empty address on other platforms
Fixes f6b3a07b7d (bpo-44493: Add missing terminated NUL in sockaddr_un's length (GH-26866)
(cherry picked from commit c22f134211)
Co-authored-by: Nir Soffer <nsoffer@redhat.com>
