Pass the PID of the native host to the Wine hosts

We need this for our watchdog.

src/common/serialization/common.h

@@ -50,12 +50,14 @@ struct HostRequest {
     PluginType plugin_type;
     std::string plugin_path;
     std::string endpoint_base_dir;
+    pid_t parent_pid;
 
     template <typename S>
     void serialize(S& s) {
         s.object(plugin_type);
         s.text1b(plugin_path, 4096);
         s.text1b(endpoint_base_dir, 4096);
+        s.value4b(parent_pid);
     }
 };
 

src/plugin/bridges/common.h

@@ -76,7 +76,8 @@ class PluginBridge {
                         HostRequest{
                             .plugin_type = plugin_type,
                             .plugin_path = info.windows_plugin_path.string(),
-                            .endpoint_base_dir = sockets.base_dir.string()},
+                            .endpoint_base_dir = sockets.base_dir.string(),
+                            .parent_pid = getpid()},
                         sockets,
                         *config.group))
                   : std::unique_ptr<HostProcess>(
@@ -88,7 +89,8 @@ class PluginBridge {
                                 .plugin_type = plugin_type,
                                 .plugin_path =
                                     info.windows_plugin_path.string(),
-                                .endpoint_base_dir = sockets.base_dir.string()},
+                                .endpoint_base_dir = sockets.base_dir.string(),
+                                .parent_pid = getpid()},
                             sockets))),
           has_realtime_priority(has_realtime_priority_promise.get_future()),
           wine_io_handler([&]() {

src/plugin/host-process.cpp

@@ -83,6 +83,10 @@ IndividualHost::IndividualHost(boost::asio::io_context& io_context,
           host_request.plugin_path,
 #endif
           host_request.endpoint_base_dir,
+          // We pass this process' process ID as an argument so we can run a
+          // watchdog on the Wine plugin host process that shuts down the
+          // sockets after this process shuts down
+          std::to_string(getpid()),
           bp::env = plugin_info.create_host_env(),
           bp::std_out = stdout_pipe,
           bp::std_err = stderr_pipe

src/wine-host/individual-host.cpp

@@ -39,20 +39,20 @@ __cdecl
     main(int argc, char* argv[]) {
     set_realtime_priority(true);
 
-    // We pass plugin format, the name of the VST2 plugin .dll file or VST3
-    // bundle to load, and the base directory for the Unix domain socket
-    // endpoints to connect to as the first two arguments of this process in
-    // `src/plugin/host-process.cpp`
-    if (argc < 4) {
-        std::cerr
-            << "Usage: "
+    // We pass the plugin format, the name of the VST2 plugin .dll file or VST3
+    // bundle to load, the base directory for the Unix domain socket endpoints
+    // to connect to and the process ID of the process the native plugin is
+    // being hosted in as arguments for yabridge-host.exe
+    if (argc < 5) {
+        std::cerr << "Usage: "
 #ifdef __i386__
-            << yabridge_individual_host_name_32bit
+                  << yabridge_individual_host_name_32bit
 #else
-            << yabridge_individual_host_name
+                  << yabridge_individual_host_name
 #endif
-            << " <plugin_type> <plugin_location> <endpoint_base_directory>"
-            << std::endl;
+                  << " <plugin_type> <plugin_location> "
+                     "<endpoint_base_directory> <parent_pid>"
+                  << std::endl;
 
         return 1;
     }
@@ -61,6 +61,7 @@ __cdecl
     const PluginType plugin_type = plugin_type_from_string(plugin_type_str);
     const std::string plugin_location(argv[2]);
     const std::string socket_endpoint_path(argv[3]);
+    const pid_t parent_pid = std::stoi(argv[4]);
 
     std::cout << "Initializing yabridge host version " << yabridge_git_version
 #ifdef __i386__