When an LSM (e.g. SELinux) denies an fd transfer or the receiver hits
RLIMIT_NOFILE, the kernel drops the fd(s) from the SCM_RIGHTS cmsg and
sets MSG_CTRUNC on the recvmsg(). recvmsg_safe() turns that into
-ECHRNG, which causes json_stream_read() to discard the data bytes
that were nevertheless received and the varlink server to silently
tear down the connection — leaving the caller waiting for a reply
that never comes.
Inline the recvmsg() call instead and, on MSG_CTRUNC, drop the partial
fds but keep the message data. The method handler will surface a clean
-ENXIO when it tries to peek the missing fd, which sd-varlink wraps as
io.systemd.System for the peer, instead of a hang. This matches the
recent sd-bus fix in 6c8de404c9 ('sd-bus: allow receiving messages with
MSG_CTRUNC set').
System and Service Manager
Details
Most documentation is available on systemd's web site.
Assorted, older, general information about systemd can be found in the systemd Wiki.
Information about build requirements is provided in the README file.
Consult our NEWS file for information about what's new in the most recent systemd versions.
Please see the Code Map for information about this repository's layout and content.
Please see the Hacking guide for information on how to hack on systemd and test your modifications.
Please see our Contribution Guidelines for more information about filing GitHub Issues and posting GitHub Pull Requests.
When preparing patches for systemd, please follow our Coding Style Guidelines.
If you are looking for support, please contact our mailing list, join our IRC channel #systemd on libera.chat or Matrix channel
Stable branches with backported patches are available in the stable repo.
We have a security bug bounty program sponsored by the Sovereign Tech Fund hosted on YesWeHack
Repositories with distribution packages built from git main are available on OBS, and also repositories with packages built from the latest stable release
