On Linux a proxy listening on a Unix socket relayed only the first
bytes of an answer (result 95): sockmap() read with recvfrom() into the
client's address, which for a Unix stream socket Linux fills with an
empty AF_UNIX one, and then sent with sendto() to that address, which a
connected Unix stream socket refuses. A TCP connection has no use for
addresses: sockmap() now sends and receives with NULL ones, and
connect-back sends its command with socksend() and reads the answer
with sockrecvfrom() without an address, which a NULL sin now allows.
An abstract socket name (-iunix:@NAME) was bound with the whole size of
struct sockaddr_un, padded with zeros, so a client naming it by its
bytes, as most do, reached another name. SASIZE() now gives an abstract
address its exact size; getsockname() calls that took SASIZE() of the
old contents as the buffer size take the buffer's size instead.
tcppm refused port 0 for a unix: target, though the manual gives
"tcppm 8080 unix:/var/run/app.sock 0" as the example: the port of a
Unix socket target is ignored, so 0 is allowed.
On a reload the new service bound the path anew and the old one,
closing after it, removed the file, the new service's by then, leaving
nothing to connect to. A service now notes the file it bound (device
and inode) and removes the path on closing only if it is still that
file.
A test case covers a proxy on a Unix socket and on an abstract one on
Linux, tcppm to a Unix socket, a parent reached through one, and a
listening Unix socket across reloads: its file kept and the proxy
answering, and the file removed once no service listens on it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
