fix: ensure IO forwarding completes when child exits early

src/linyaps_box/container.cpp

@@ -2489,9 +2489,7 @@ int linyaps_box::container::run(run_container_options_t options) const
             monitor.enable_io_forwarding(std::move(master), in, out);
         }();
 
-        if (!monitor.enable_signal_forwarding()) {
-            return 0;
-        }
+        monitor.enable_signal_forwarding();
 
         // TODO: support detach from the parent's process
         // Now we wait for the container process to exit

src/linyaps_box/container_monitor.cpp

@@ -17,7 +17,7 @@
 
 namespace linyaps_box {
 
-auto container_monitor::enable_signal_forwarding() -> bool
+auto container_monitor::enable_signal_forwarding() -> void
 {
     sigset_t set;
     utils::sigfillset(set);
@@ -43,11 +43,6 @@ auto container_monitor::enable_signal_forwarding() -> bool
             continue;
         }
 
-        if (ret.status == linyaps_box::utils::WaitStatus::NoChild) {
-            // no child process to wait, just exit
-            return false;
-        }
-
         break;
     }
 
@@ -56,8 +51,6 @@ auto container_monitor::enable_signal_forwarding() -> bool
     if (!UNLIKELY(signalfd_pollable)) {
         throw std::runtime_error("failed to add signalfd to epoll");
     }
-
-    return true;
 }
 
 auto container_monitor::handle_signals() -> void

src/linyaps_box/container_monitor.h

@@ -22,7 +22,7 @@ class container_monitor
     container_monitor &operator=(container_monitor &&) = delete;
     ~container_monitor() = default;
 
-    [[nodiscard]] auto enable_signal_forwarding() -> bool;
+    auto enable_signal_forwarding() -> void;
     auto enable_io_forwarding(terminal_master master,
                               const linyaps_box::utils::file_descriptor &in,
                               const linyaps_box::utils::file_descriptor &out) -> void;

src/linyaps_box/container_ref.cpp

@@ -144,10 +144,7 @@ auto linyaps_box::container_ref::exec(exec_container_option option) -> int
         monitor.enable_io_forwarding(std::move(master), in, out);
     }();
 
-    if (!monitor.enable_signal_forwarding()) {
-        return 0;
-    }
-
+    monitor.enable_signal_forwarding();
     return monitor.wait_container_exit();
 }