core: rework unit name validation and manipulation logic

A variety of changes:

- Make sure all our calls distuingish OOM from other errors if OOM is
  not the only error possible.

- Be much stricter when parsing escaped paths, do not accept trailing or
  leading escaped slashes.

- Change unit validation to take a bit mask for allowing plain names,
  instance names or template names or an combination thereof.

- Refuse manipulating invalid unit name

1 files changed, 2 insertions, 2 deletions

diff --git a/src/core/snapshot.c b/src/core/snapshot.c
index b70c3beb60..2c00680f16 100644
--- a/src/core/snapshot.c
+++ b/src/core/snapshot.c
@@ -201,10 +201,10 @@ int snapshot_create(Manager *m, const char *name, bool cleanup, sd_bus_error *e,
         assert(_s);
 
         if (name) {
-                if (!unit_name_is_valid(name, TEMPLATE_INVALID))
+                if (!unit_name_is_valid(name, UNIT_NAME_PLAIN))
                         return sd_bus_error_setf(e, SD_BUS_ERROR_INVALID_ARGS, "Unit name %s is not valid.", name);
 
-                if (unit_name_to_type(name) != UNIT_SNAPSHOT)
+                if (!endswith(name, ".snapshot"))
                         return sd_bus_error_setf(e, SD_BUS_ERROR_INVALID_ARGS, "Unit name %s lacks snapshot suffix.", name);
 
                 if (manager_get_unit(m, name))