core: split out unit bus path unescaping into unit_name_from_dbus_path()

src/core/manager.c

@@ -1783,7 +1783,7 @@ int manager_loop(Manager *m) {
 }
 
 int manager_load_unit_from_dbus_path(Manager *m, const char *s, DBusError *e, Unit **_u) {
-        char *n;
+        _cleanup_free_ char *n = NULL;
         Unit *u;
         int r;
 
@@ -1791,16 +1791,11 @@ int manager_load_unit_from_dbus_path(Manager *m, const char *s, DBusError *e, Un
         assert(s);
         assert(_u);
 
-        if (!startswith(s, "/org/freedesktop/systemd1/unit/"))
-                return -EINVAL;
-
-        n = bus_path_unescape(s+31);
-        if (!n)
-                return -ENOMEM;
+        r = unit_name_from_dbus_path(s, &n);
+        if (r < 0)
+                return r;
 
         r = manager_load_unit(m, n, NULL, e, &u);
-        free(n);
-
         if (r < 0)
                 return r;
 

src/shared/unit-name.c

@@ -467,6 +467,22 @@ char *unit_dbus_path_from_name(const char *name) {
         return strappend("/org/freedesktop/systemd1/unit/", e);
 }
 
+int unit_name_from_dbus_path(const char *path, char **name) {
+        const char *e;
+        char *n;
+
+        e = startswith(path, "/org/freedesktop/systemd1/unit/");
+        if (!e)
+                return -EINVAL;
+
+        n = bus_path_unescape(e);
+        if (!n)
+                return -ENOMEM;
+
+        *name = n;
+        return 0;
+}
+
 char *unit_name_mangle(const char *name) {
         char *r, *t;
         const char *f;

src/shared/unit-name.h

@@ -95,6 +95,7 @@ char *unit_name_from_path_instance(const char *prefix, const char *path, const c
 char *unit_name_to_path(const char *name);
 
 char *unit_dbus_path_from_name(const char *name);
+int unit_name_from_dbus_path(const char *path, char **name);
 
 char *unit_name_mangle(const char *name);
 char *unit_name_mangle_with_suffix(const char *name, const char *suffix);