qmp-client: widen next_fdset_id to uint64_t

The fdset id is a monotonic counter; an unsigned int is more than wide
enough today, but uint64_t matches the type of other QMP-internal counters
(e.g. job ids) and avoids any worry about wraparound on long-running
hosts. Update the storage in struct QmpClient, the qmp_client_next_fdset_id()
return type, and the corresponding caller in qmp_fdset_add(), switching the
sprintf format from %u to PRIu64.

No behavioural change.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

src/shared/qmp-client.c

@@ -45,7 +45,7 @@ struct QmpClient {
         qmp_disconnect_callback_t disconnect_callback;
         void *disconnect_userdata;
 
-        unsigned next_fdset_id;   /* monotonic fdset-id allocator for add-fd */
+        uint64_t next_fdset_id;   /* monotonic fdset-id allocator for add-fd */
 
         QmpClientState state;
         sd_json_variant *current;  /* most recently parsed message, pending dispatch */
@@ -893,7 +893,7 @@ sd_event* qmp_client_get_event(QmpClient *c) {
         return json_stream_get_event(&c->stream);
 }
 
-unsigned qmp_client_next_fdset_id(QmpClient *c) {
+uint64_t qmp_client_next_fdset_id(QmpClient *c) {
         assert(c);
         return c->next_fdset_id++;
 }

src/shared/qmp-client.h

@@ -82,7 +82,7 @@ void qmp_client_bind_event(QmpClient *c, qmp_event_callback_t callback, void *us
 void qmp_client_bind_disconnect(QmpClient *c, qmp_disconnect_callback_t callback, void *userdata);
 int qmp_client_set_description(QmpClient *c, const char *description);
 sd_event* qmp_client_get_event(QmpClient *c);
-unsigned qmp_client_next_fdset_id(QmpClient *client);
+uint64_t qmp_client_next_fdset_id(QmpClient *client);
 
 DECLARE_TRIVIAL_REF_UNREF_FUNC(QmpClient, qmp_client);
 DEFINE_TRIVIAL_CLEANUP_FUNC(QmpClient *, qmp_client_unref);

src/vmspawn/vmspawn-qmp.c

@@ -128,7 +128,7 @@ static int qmp_fdset_add(QmpClient *qmp, int fd_consume, char **ret_path) {
         _cleanup_(sd_json_variant_unrefp) sd_json_variant *args = NULL;
         _cleanup_close_ int fd = fd_consume;
         _cleanup_free_ char *path = NULL;
-        unsigned id;
+        uint64_t id;
         int r;
 
         assert(qmp);
@@ -141,7 +141,7 @@ static int qmp_fdset_add(QmpClient *qmp, int fd_consume, char **ret_path) {
         if (r < 0)
                 return r;
 
-        if (asprintf(&path, "/dev/fdset/%u", id) < 0)
+        if (asprintf(&path, "/dev/fdset/%" PRIu64, id) < 0)
                 return -ENOMEM;
 
         r = qmp_client_invoke(qmp, /* ret_slot= */ NULL, "add-fd", QMP_CLIENT_ARGS_FD(args, TAKE_FD(fd)),