systemctl: automatically turn paths and unescaped unit names into proper unit names

This makes sure that

  systemctl status /home

is implicitly translated to:

  systemctl status /home.mount

Similar, /dev/foobar becomes dev-foobar.device.

Also, all characters that cannot be part of a unit name are implicitly
escaped.

src/test/test-hostname.c

@@ -30,7 +30,8 @@
 int main(int argc, char* argv[]) {
         int r;
 
-        if ((r = hostname_setup()) < 0)
+        r = hostname_setup();
+        if (r < 0)
                 fprintf(stderr, "hostname: %s\n", strerror(-r));
 
         return 0;

src/test/test-unit-name.c

@@ -0,0 +1,82 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2012 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "unit-name.h"
+#include "util.h"
+
+int main(int argc, char* argv[]) {
+        char *t, *k;
+
+        assert_se(t = unit_name_mangle("/home"));
+        assert_se(k = unit_name_mangle(t));
+        puts(t);
+        assert_se(streq(t, k));
+        free(t);
+        free(k);
+
+        assert_se(t = unit_name_mangle("/dev/sda"));
+        assert_se(k = unit_name_mangle(t));
+        puts(t);
+        assert_se(streq(t, k));
+        free(t);
+        free(k);
+
+        assert_se(t = unit_name_mangle("üxknürz.service"));
+        assert_se(k = unit_name_mangle(t));
+        puts(t);
+        assert_se(streq(t, k));
+        free(t);
+        free(k);
+
+        assert_se(t = unit_name_mangle("foobar-meh...waldi.service"));
+        assert_se(k = unit_name_mangle(t));
+        puts(t);
+        assert_se(streq(t, k));
+        free(t);
+        free(k);
+
+        assert_se(t = unit_name_mangle("_____####----.....service"));
+        assert_se(k = unit_name_mangle(t));
+        puts(t);
+        assert_se(streq(t, k));
+        free(t);
+        free(k);
+
+        assert_se(t = unit_name_mangle("_____##@;;;,,,##----.....service"));
+        assert_se(k = unit_name_mangle(t));
+        puts(t);
+        assert_se(streq(t, k));
+        free(t);
+        free(k);
+
+        assert_se(t = unit_name_mangle("xxx@@@@/////\\\\\\\\\\yyy.service"));
+        assert_se(k = unit_name_mangle(t));
+        puts(t);
+        assert_se(streq(t, k));
+        free(t);
+        free(k);
+
+        return 0;
+}