d-s-h: don’t error out when masking a service is not possible becausedebian/1.17

/etc/systemd/system/<service> already exists (but is not a symlink).

Closes: #739090

3 files changed, 50 insertions, 2 deletions

diff --git a/debian/changelog b/debian/changelog
index 9859f01..36e74b8 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,11 @@
+init-system-helpers (1.17) unstable; urgency=low
+
+  * d-s-h: don’t error out when masking a service is not possible because
+    /etc/systemd/system/<service> already exists (but is not a symlink).
+    (Closes: #739090)
+
+ -- Michael Stapelberg <stapelberg@debian.org>  Tue, 18 Feb 2014 20:52:20 +0100
+
 init-system-helpers (1.16) unstable; urgency=low
 
   * Don’t delete /etc/systemd/, only the hierarchy below /etc/systemd/system/.
diff --git a/script/deb-systemd-helper b/script/deb-systemd-helper
index f6b0fe7..efb6fe3 100755
--- a/script/deb-systemd-helper
+++ b/script/deb-systemd-helper
@@ -377,8 +377,12 @@ sub mask_service {
         # If the link already exists, don’t do anything.
         return if -l $mask_link && readlink($mask_link) eq '/dev/null';
 
-        # Otherwise, error out.
-        error("$mask_link already exists");
+        # If the file already exists, the user most likely copied the .service
+        # file to /etc/ to change it in some way. In this case we don’t need to
+        # mask the .service in the first place, since it will not be removed by
+        # dpkg.
+        debug "$mask_link already exists, not masking.";
+        return;
     }
 
     make_path(dirname($mask_link));
diff --git a/t/001-deb-systemd-helper.t b/t/001-deb-systemd-helper.t
index 4d814ea..652e3d1 100644
--- a/t/001-deb-systemd-helper.t
+++ b/t/001-deb-systemd-helper.t
@@ -208,4 +208,40 @@ $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');
 
+# ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
+# ┃ Verify “mask”/unmask don’t do anything when the user copied the .service. ┃
+# ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
+
+unlink($mask_path);
+
+open($fh, '>', $mask_path);
+print $fh <<'EOT';
+[Unit]
+Description=test unit
+
+[Service]
+ExecStart=/bin/sleep 1
+
+[Install]
+WantedBy=multi-user.target
+EOT
+close($fh);
+
+ok(-e $mask_path, 'local service file exists');
+ok(! -l $mask_path, 'local service file is not a symlink');
+
+$retval = system("DPKG_MAINTSCRIPT_PACKAGE=test $dsh mask $random_unit");
+isnt($retval, -1, 'deb-systemd-helper could be executed');
+ok(!($retval & 127), 'deb-systemd-helper did not exit due to a signal');
+is($retval >> 8, 0, 'deb-systemd-helper exited with exit code 0');
+ok(-e $mask_path, 'local service file still exists');
+ok(! -l $mask_path, 'local service file is still not a symlink');
+
+$retval = system("DPKG_MAINTSCRIPT_PACKAGE=test $dsh unmask $random_unit");
+isnt($retval, -1, 'deb-systemd-helper could be executed');
+ok(!($retval & 127), 'deb-systemd-helper did not exit due to a signal');
+is($retval >> 8, 0, 'deb-systemd-helper exited with exit code 0');
+ok(-e $mask_path, 'local service file still exists');
+ok(! -l $mask_path, 'local service file is still not a symlink');
+
 done_testing;