systemd-systemctl: fix instance template WantedBy symlink construction

Fix issue of the below instance template systemd service dependency

[Install]
WantedBy=svc-wants@%i.service

creating the symlink (instance "a" example)

/etc/systemd/system/svc-wants@%i.service.wants/svc-wanted-by@a.service

which should be

/etc/systemd/system/svc-wants@a.service.wants/svc-wanted-by@a.service

as implemented by this change.

The functionality appears regressed just after "thud" baseline when the
logic was refactored from shell script into python (commit
925e30cb104ece7bfa48b78144e758a46dc9ec3f)

(From OE-Core rev: 308397f0bb3d6f3d4e9ec2c6a10823184049c9b5)

Signed-off-by: Martin Siegumfeldt <mns@gomspace.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
(cherry picked from commit 372b29c8ad270d4d430c26a4e614976c7029afaf)
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/meta/recipes-core/systemd/systemd-systemctl/systemctl b/meta/recipes-core/systemd/systemd-systemctl/systemctl
index 6d19666d82..1c87beadad 100755
--- a/meta/recipes-core/systemd/systemd-systemctl/systemctl
+++ b/meta/recipes-core/systemd/systemd-systemctl/systemctl
@@ -184,12 +184,19 @@ class SystemdUnit():
 
         raise SystemdUnitNotFoundError(self.root, unit)
 
-    def _process_deps(self, config, service, location, prop, dirstem):
+    def _process_deps(self, config, service, location, prop, dirstem, instance):
         systemdir = self.root / SYSCONFDIR / "systemd" / "system"
 
         target = ROOT / location.relative_to(self.root)
         try:
             for dependent in config.get('Install', prop):
+                # determine whether or not dependent is a template with an actual
+                # instance (i.e. a '@%i')
+                dependent_is_template = re.match(r"[^@]+@(?P<instance>[^\.]*)\.", dependent)
+                if dependent_is_template:
+                    # if so, replace with the actual instance to achieve
+                    # svc-wants@a.service.wants/svc-wanted-by@a.service
+                    dependent = re.sub(dependent_is_template.group('instance'), instance, dependent, 1)
                 wants = systemdir / "{}.{}".format(dependent, dirstem) / service
                 add_link(wants, target)
 
@@ -229,8 +236,8 @@ class SystemdUnit():
         else:
             service = self.unit
 
-        self._process_deps(config, service, path, 'WantedBy', 'wants')
-        self._process_deps(config, service, path, 'RequiredBy', 'requires')
+        self._process_deps(config, service, path, 'WantedBy', 'wants', instance)
+        self._process_deps(config, service, path, 'RequiredBy', 'requires', instance)
 
         try:
             for also in config.get('Install', 'Also'):