Each proxied connection uses eight file descriptors: the accepted and the
outgoing socket, a duplicate of each, and a pipe for each direction. With
the default soft RLIMIT_NOFILE of 1024, setting up forwarding fails with
"Too many open files" at about 127 concurrent connections, well before
the default --connections-max=256, and the connection is closed right
after being accepted.
socket-proxyd's I/O is sd-event based and handles fds above 1023, so it
does not need the select()-compatible soft limit. Call
rlimit_nofile_bump(-1) at startup to raise RLIMIT_NOFILE as far as
permitted, like udevd does.
(cherry picked from commit 98752540be47778e253cbafe51c7ccdd30f4995e)
Kamil Monicz
bcf0a9ac58