start: Make lxc_handler mainloop to run in thread

This allows applying Landlock restrictions just to the monitor handler.

Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>

diff --git a/src/lxc/start.c b/src/lxc/start.c
index 3160459b46f26635cc6e10451f4aea24388f7477..b5e27eed35673899f25636d8828f427acd5fdd89 100644 (file)
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -572,6 +572,38 @@ int lxc_set_state(const char *name, struct lxc_handler *handler,
        return 0;
 }
 
+void *lxc_handler_mainloop_thread_fn(void *arg)
+{
+       struct lxc_async_descr *descr = arg;
+
+       return INT_TO_PTR(lxc_mainloop(descr, -1));
+}
+
+int lxc_handler_mainloop(struct lxc_async_descr *descr, struct lxc_handler *handler)
+{
+       void *exit_code;
+       int ret;
+       pthread_t thread;
+
+       ret = pthread_create(&thread, NULL, lxc_handler_mainloop_thread_fn, (void *)descr);
+       if (ret) {
+               return log_error_errno(-1, ret,
+                                      "Failed to spawn a thread for lxc handler mainloop");
+       }
+
+       ret = pthread_join(thread, &exit_code);
+       if (ret) {
+               return log_error_errno(-1, ret,
+                                      "Failed to wait for lxc handler mainloop thread");
+       }
+
+       if (exit_code == PTHREAD_CANCELED) {
+               return log_error(-1, "Mainloop thread was canceled");
+       }
+
+       return PTR_TO_INT(exit_code);
+}
+
 int lxc_poll(const char *name, struct lxc_handler *handler)
 {
        int ret;
@@ -626,7 +658,7 @@ int lxc_poll(const char *name, struct lxc_handler *handler)
 
        TRACE("Mainloop is ready");
 
-       ret = lxc_mainloop(&descr, -1);
+       ret = lxc_handler_mainloop(&descr, handler);
        if (descr.type == LXC_MAINLOOP_EPOLL)
                close_prot_errno_disarm(descr.epfd);
        if (ret < 0 || !handler->init_died)