logind: rework Seat/Session/User object allocation and freeing a bit

Let's update things a bit to follow current practices:

- User structure initialization rather than zero-initialized allocation

- Always propagate proper errors from allocation functions

- Use _cleanup_ for freeing objects when allocation fails half-way

- Make destructors return NULL

(cherry picked from commit 8c29a4570993105fecc12288596d2ee77c7f82b8)

1 files changed, 8 insertions, 6 deletions

diff --git a/src/login/logind-core.c b/src/login/logind-core.c
index db0df19e2..7e096277b 100644
--- a/src/login/logind-core.c
+++ b/src/login/logind-core.c
@@ -102,15 +102,16 @@ int manager_add_device(Manager *m, const char *sysfs, bool master, Device **_dev
 
 int manager_add_seat(Manager *m, const char *id, Seat **_seat) {
         Seat *s;
+        int r;
 
         assert(m);
         assert(id);
 
         s = hashmap_get(m->seats, id);
         if (!s) {
-                s = seat_new(m, id);
-                if (!s)
-                        return -ENOMEM;
+                r = seat_new(&s, m, id);
+                if (r < 0)
+                        return r;
         }
 
         if (_seat)
@@ -121,15 +122,16 @@ int manager_add_seat(Manager *m, const char *id, Seat **_seat) {
 
 int manager_add_session(Manager *m, const char *id, Session **_session) {
         Session *s;
+        int r;
 
         assert(m);
         assert(id);
 
         s = hashmap_get(m->sessions, id);
         if (!s) {
-                s = session_new(m, id);
-                if (!s)
-                        return -ENOMEM;
+                r = session_new(&s, m, id);
+                if (r < 0)
+                        return r;
         }
 
         if (_session)