service: set TRIGGER_UNIT= and TRIGGER_PATH= on activation by path unit

When a service is triggered by a path unit, pass the
path unit name and the path that triggered it via env vars
to the spawned processes.
Note that this is best-effort, as there might be many triggers
at the same time, but we only get woken up by one.

test/testsuite-63.units/test63-glob.path

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Path]
+PathExistsGlob=/tmp/test63-glob*

test/testsuite-63.units/test63-glob.service

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Service]
+ExecStartPre=sh -c 'test "$TRIGGER_PATH" = /tmp/test63-glob-foo'
+ExecStartPre=sh -c 'test "$TRIGGER_UNIT" = test63-glob.path'
+ExecStart=systemd-notify --ready
+RemainAfterExit=yes
+Type=notify

test/testsuite-63.units/test63.service

@@ -3,4 +3,6 @@
 ConditionPathExists=/tmp/nonexistent
 
 [Service]
+ExecStartPre=sh -c 'test "$TRIGGER_PATH" = /tmp/test63'
+ExecStartPre=sh -c 'test "$TRIGGER_UNIT" = test63.path'
 ExecStart=true

test/units/testsuite-63.sh

@@ -28,6 +28,19 @@ test "$(systemctl show test63.service -P Result)" = success
 test "$(systemctl show test63.path -P ActiveState)" = active
 test "$(systemctl show test63.path -P Result)" = success
 
+# Test that glob matching works too, with $TRIGGER_PATH
+systemctl start test63-glob.path
+touch /tmp/test63-glob-foo
+timeout 60 bash -c 'while ! systemctl -q is-active test63-glob.service; do sleep .2; done'
+test "$(systemctl show test63-glob.service -P ActiveState)" = active
+test "$(systemctl show test63-glob.service -P Result)" = success
+
+test "$(busctl --json=short get-property org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/test63_2dglob_2eservice org.freedesktop.systemd1.Unit ActivationDetails)" = '{"type":"a(ss)","data":[["trigger_unit","test63-glob.path"],["trigger_path","/tmp/test63-glob-foo"]]}'
+
+systemctl stop test63-glob.path test63-glob.service
+
+test "$(busctl --json=short get-property org.freedesktop.systemd1 /org/freedesktop/systemd1/unit/test63_2dglob_2eservice org.freedesktop.systemd1.Unit ActivationDetails)" = '{"type":"a(ss)","data":[]}'
+
 systemctl log-level info
 
 echo OK >/testok