On 21 August 2016 at 12:37, Christian Heimes <christ...@python.org> wrote: > the socket.setsockopt(level, optname, value) method has two calling > variants. When it is called with a buffer-like object as value, it calls > the C API function setsockopt() with optval=buffer.buf and > optlen=buffer.len. When value is an integer, setsockopt() packs it as > int32 and sends it with optlen=4. > > --- > # example.py > import socket > sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) > sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, > b'\x00\x00\x00\x00') > sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) > --- > > $ strace -e setsockopt ./python example.py > setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [0], 4) = 0 > setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 > > > For AF_ALG (Linux Kernel crypto) I need a way to call the C API function > setsockopt() with optval=NULL and optlen as any arbitrary number. I have > been playing with multiple ideas. So far I liked the idea of > value=(None, int) most. > > setsockopt(socket.SOL_ALG, socket.ALG_SET_AEAD_AUTHSIZE, (None, taglen))
Would this new functionality be open-ended? What would happen if you did sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, (None, 4)) On Linux, this seems to fail with errno = EFAULT, which would be fine. But this does not seem to be specified by Posix, and I imagine other platforms might crash. On the other hand, these sort of holes are already present in the socket module. E.g. with MSG_TRUNC <https://bugs.python.org/issue24933> you can apparently get Python to copy from unallocated memory. _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
