Re: [libvirt] [PATCH 06/23] util: add APIs for facilitating use of systemd activation FDs

When receiving multiple FDs from systemd during service activation it is neccessary to identify which purpose each FD is used for. While this could be inferred by looking for the specific IP ports or UNIX socket paths, this requires the systemd config to always match what is expected by the code. Using systemd FD names we can remove this restriction and simply identify FDs based on an arbitrary name. The FD names are passed by systemd in the LISTEN_FDNAMES env variable which is populated with the socket unit file names, unless overriden by using the FileDescriptorName setting. This is supported since the system 227 release and unfortunately RHEL7 lacks this version. Thus the code has some back compat support whereby we look at the TCP ports or the UNIX socket paths to identify what socket maps to which name. This back compat code is written such that is it easly deleted when we are able to mandate newer systemd. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- src/libvirt_private.syms | 5 + src/util/virsystemd.c | 362 +++++++++++++++++++++++++++++++++++++++ src/util/virsystemd.h | 30 ++++ tests/virsystemdtest.c | 169 ++++++++++++++++++ 4 files changed, 566 insertions(+) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 1adf735a38..ee1073e680 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -3102,6 +3102,11 @@ virSysinfoReadS390; # util/virsystemd.h +virSystemdGetActivation; +virSystemdActivationClaimFDs; +virSystemdActivationComplete; +virSystemdActivationFree; +virSystemdActivationHasName; virSystemdCanHibernate; virSystemdCanHybridSleep; virSystemdCanSuspend;