nspawn: register a scope for the unit if --register=no is specified (#6166)

Previously, only when --register=yes was set (the default) the invoked
container would get its own scope, created by machined on behalf of
nspawn. With this change if --register=no is set nspawn will still get
its own scope (which is a good thing, so that --slice= and --property=
take effect), but this is not done through machined but by registering a
scope unit directly in PID 1.

Summary:

--register=yes             → allocate a new scope through machined (the default)
--register=yes --keep-unit → use the unit we are already running in an register with machined
--register=no              → allocate a new scope directly, but no machined
--register=no --keep-unit  → do not allocate nor register anything

Fixes: #5823

1 files changed, 2 insertions, 0 deletions

diff --git a/src/nspawn/nspawn-register.h b/src/nspawn/nspawn-register.h
index 304c5a485b..6694b3f6b1 100644
--- a/src/nspawn/nspawn-register.h
+++ b/src/nspawn/nspawn-register.h
@@ -27,3 +27,5 @@
 
 int register_machine(const char *machine_name, pid_t pid, const char *directory, sd_id128_t uuid, int local_ifindex, const char *slice, CustomMount *mounts, unsigned n_mounts, int kill_signal, char **properties, bool keep_unit, const char *service);
 int terminate_machine(pid_t pid);
+
+int allocate_scope(const char *machine_name, pid_t pid, const char *slice, CustomMount *mounts, unsigned n_mounts, int kill_signal, char **properties);