#714 yabai message receiver could get stuck in *recv* on Big Sur

CHANGELOG.md

@@ -5,6 +5,8 @@ All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- Fixed an issue (exposed on Big Sur, maybe didn't exist on prior macOS versions ??) that caused yabai' message receiver to block in *recv* [#714](https://github.com/koekeishiya/yabai/issues/714)
 
 ## [3.3.3] - 2020-11-13
 ### Changed

src/event.c

@@ -1003,17 +1003,23 @@ static EVENT_CALLBACK(EVENT_HANDLER_SYSTEM_WOKE)
 
 static EVENT_CALLBACK(EVENT_HANDLER_DAEMON_MESSAGE)
 {
+    int length;
+    char *message = socket_read(param1, &length);
+    if (!message) goto out;
+
     FILE *rsp = fdopen(param1, "w");
-    if (!rsp) goto out;
+    if (!rsp) goto err;
+
+    debug_message(__FUNCTION__, message);
+    handle_message(rsp, message);
 
-    debug_message(__FUNCTION__, context);
-    handle_message(rsp, context);
     fflush(rsp);
     fclose(rsp);
 
-out:
-    socket_close(param1);
+err:
     free(context);
 
+out:
+    socket_close(param1);
     return EVENT_SUCCESS;
 }

src/message.c

@@ -2293,5 +2293,5 @@ void handle_message(FILE *rsp, char *message)
 
 static SOCKET_DAEMON_HANDLER(message_handler)
 {
-    event_loop_post(&g_event_loop, DAEMON_MESSAGE, message, sockfd, NULL);
+    event_loop_post(&g_event_loop, DAEMON_MESSAGE, NULL, sockfd, NULL);
 }

src/misc/socket.c

@@ -96,15 +96,7 @@ static void *socket_connection_handler(void *context)
 
     while (daemon->is_running) {
         int sockfd = accept(daemon->sockfd, NULL, 0);
-        if (sockfd == -1) continue;
-
-        int length;
-        char *message = socket_read(sockfd, &length);
-        if (message) {
-            daemon->handler(message, length, sockfd);
-        } else {
-            socket_close(sockfd);
-        }
+        if (sockfd != -1) daemon->handler(sockfd);
     }
 
     return NULL;

src/misc/socket.h

@@ -1,7 +1,7 @@
 #ifndef SOCKET_H
 #define SOCKET_H
 
-#define SOCKET_DAEMON_HANDLER(name) void name(char *message, int length, int sockfd)
+#define SOCKET_DAEMON_HANDLER(name) void name(int sockfd)
 typedef SOCKET_DAEMON_HANDLER(socket_daemon_handler);
 
 #define FAILURE_MESSAGE "\x07"