Store masked state to respect user’s maskingdebian/1.10

We cannot just unconditionally unmask services on installation time,
otherwise “systemctl mask” executed by the user will be reversed.

To that end, files in /var/lib/systemd/deb-systemd-helper-masked/ signal
that d-s-h masked the service and is allowed to unmask it.

1 files changed, 17 insertions, 0 deletions

diff --git a/t/001-deb-systemd-helper.t b/t/001-deb-systemd-helper.t
index 5bb9ecd..4d814ea 100644
--- a/t/001-deb-systemd-helper.t
+++ b/t/001-deb-systemd-helper.t
@@ -191,4 +191,21 @@ is(readlink($mask_path), '/dev/null', 'service masked');
 $retval = system("DPKG_MAINTSCRIPT_PACKAGE=test $dsh unmask $random_unit");
 ok(! -e $mask_path, 'symlink no longer exists');
 
+# ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
+# ┃ Verify “mask”/unmask don’t do anything when the user already masked.      ┃
+# ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
+
+ok(! -l $mask_path, 'mask link does not exist yet');
+symlink('/dev/null', $mask_path);
+ok(-l $mask_path, 'mask link exists');
+is(readlink($mask_path), '/dev/null', 'service masked');
+
+$retval = system("DPKG_MAINTSCRIPT_PACKAGE=test $dsh mask $random_unit");
+ok(-l $mask_path, 'mask link exists');
+is(readlink($mask_path), '/dev/null', 'service still masked');
+
+$retval = system("DPKG_MAINTSCRIPT_PACKAGE=test $dsh unmask $random_unit");
+ok(-l $mask_path, 'mask link exists');
+is(readlink($mask_path), '/dev/null', 'service still masked');
+
 done_testing;