[config] Try to set notifier file descriptor to non-blocking mode; add start/stop_notifier functions

If setting to non-blocking fails, just closing the fd should kill it anyway

src/gl/inject.cpp

@@ -73,7 +73,7 @@ static std::string deviceName;
 
 // seems to quit by itself though
 static std::unique_ptr<notify_thread, std::function<void(notify_thread *)>>
-    stop_notifier(&notifier, [](notify_thread *n){ n->quit = true; });
+    stop_it(&notifier, [](notify_thread *n){ stop_notifier(*n); });
 
 void imgui_init()
 {
@@ -81,7 +81,7 @@ void imgui_init()
         return;
     parse_overlay_config(&params, getenv("MANGOHUD_CONFIG"));
     notifier.params = &params;
-    pthread_create(&fileChange, NULL, &fileChanged, &notifier);
+    start_notifier(notifier);
     window_size = ImVec2(params.width, params.height);
     init_system_info();
     cfg_inited = true;

src/notify.cpp

@@ -1,4 +1,7 @@
+#include <thread>
+#include <chrono>
 #include <unistd.h>
+#include <fcntl.h>
 #include <sys/types.h>
 #include <sys/inotify.h>
 #include "config.h"
@@ -9,22 +12,13 @@ pthread_t fileChange;
 #define EVENT_SIZE  ( sizeof (struct inotify_event) )
 #define EVENT_BUF_LEN     ( 1024 * ( EVENT_SIZE + 16 ) )
 
-void *fileChanged(void *params_void){
+static void *fileChanged(void *params_void) {
     notify_thread *nt = reinterpret_cast<notify_thread *>(params_void);
     int length, i = 0;
-    int fd;
-    int wd;
     char buffer[EVENT_BUF_LEN];
-    fd = inotify_init();
-    wd = inotify_add_watch( fd, nt->params->config_file_path.c_str(), IN_MODIFY);
-
-    if (wd < 0) {
-        close(fd);
-        return nullptr;
-    }
 
     while (!nt->quit) {
-        length = read( fd, buffer, EVENT_BUF_LEN );
+        length = read( nt->fd, buffer, EVENT_BUF_LEN );
         while (i < length) {
             struct inotify_event *event =
                 (struct inotify_event *) &buffer[i];
@@ -35,9 +29,39 @@ void *fileChanged(void *params_void){
             }
         }
         i = 0;
-        printf("File Changed\n");
+        std::this_thread::sleep_for(std::chrono::milliseconds(10));
     }
-    inotify_rm_watch(fd, wd);
-    close(fd);
+    printf("%s quit\n", __func__);
     return nullptr;
 }
+
+bool start_notifier(notify_thread& nt)
+{
+    nt.fd = inotify_init();
+    nt.wd = inotify_add_watch( nt.fd, nt.params->config_file_path.c_str(), IN_MODIFY);
+
+    int flags = fcntl(nt.fd, F_GETFL, 0);
+    if (fcntl(nt.fd, F_SETFL, flags | O_NONBLOCK))
+        perror("Set non-blocking failed");
+
+    if (nt.wd < 0) {
+        close(nt.fd);
+        nt.fd = -1;
+        return false;
+    }
+
+    pthread_create(&fileChange, NULL, &fileChanged, &nt);
+
+    return true;
+}
+
+void stop_notifier(notify_thread& nt)
+{
+    if (nt.fd < 0)
+        return;
+
+    nt.quit = true;
+    inotify_rm_watch(nt.fd, nt.wd);
+    close(nt.fd);
+    nt.fd = -1;
+}

src/notify.h

@@ -1,13 +1,13 @@
-#include <thread>
 #include <mutex>
 #include "overlay_params.h"
 
 struct notify_thread
 {
+    int fd = -1, wd = -1;
     overlay_params *params = nullptr;
     bool quit = false;
     std::mutex mutex;
 };
 
-extern pthread_t fileChange;
-extern void *fileChanged(void *params_void);
+bool start_notifier(notify_thread& nt);
+void stop_notifier(notify_thread& nt);

src/overlay.cpp

@@ -2659,7 +2659,7 @@ static VkResult overlay_CreateInstance(
 
    parse_overlay_config(&instance_data->params, getenv("MANGOHUD_CONFIG"));
    instance_data->notifier.params = &instance_data->params;
-   pthread_create(&fileChange, NULL, &fileChanged, &instance_data->notifier);
+   start_notifier(instance_data->notifier);
 
    init_cpu_stats(instance_data->params);
 
@@ -2685,7 +2685,7 @@ static void overlay_DestroyInstance(
    struct instance_data *instance_data = FIND(struct instance_data, instance);
    instance_data_map_physical_devices(instance_data, false);
    instance_data->vtable.DestroyInstance(instance, pAllocator);
-   instance_data->notifier.quit = true;
+   stop_notifier(instance_data->notifier);
    destroy_instance_data(instance_data);
 }