From 7373d2362a8d7baea516026b7e135e8ce6048531 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 5 Apr 2025 13:15:05 +0530
Subject: [PATCH] Fork to handle quicklook clients

---
 src/calibre/srv/render_book.py   | 20 ++++++++++++++++++--
 src/calibre/utils/safe_atexit.py |  6 ++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/calibre/srv/render_book.py b/src/calibre/srv/render_book.py
index f9343f1194..d592a26773 100644
--- a/src/calibre/srv/render_book.py
+++ b/src/calibre/srv/render_book.py
@@ -909,18 +909,34 @@ def quicklook_service(path_to_socket: str) -> None:
     '''
     import socket
     from contextlib import closing, suppress
+
+    from calibre.constants import debug
+    from calibre.ptempfile import reset_base_dir
+    from calibre.utils.safe_atexit import remove_file_atexit, reset_after_fork
+    debug(False)
     s = socket.socket(socket.AF_UNIX)
     s.setblocking(True)
     s.bind(path_to_socket)
     with suppress(KeyboardInterrupt), closing(s):
         if path_to_socket and not path_to_socket.startswith('\0'):
-            from calibre.utils.safe_atexit import remove_file_atexit
             remove_file_atexit(path_to_socket)
         s.listen(16)
         while True:
             c, addr = s.accept()
             c.setblocking(True)
-            handle_quicklook_client(c)
+            os.set_inheritable(c.fileno(), True)
+            if child_pid := os.fork():  # parent
+                c.close()
+                os.waitpid(child_pid, 0)
+            else:  # child
+                os.set_inheritable(c.fileno(), False)
+                reset_after_fork()
+                reset_base_dir()
+                try:
+                    handle_quicklook_client(c)
+                finally:
+                    c.shutdown(socket.SHUT_RDWR)
+                    c.close()
 
 
 class Profiler:
diff --git a/src/calibre/utils/safe_atexit.py b/src/calibre/utils/safe_atexit.py
index bd85806563..8785c0ff66 100644
--- a/src/calibre/utils/safe_atexit.py
+++ b/src/calibre/utils/safe_atexit.py
@@ -66,6 +66,12 @@ def ensure_worker():
     return worker
 
 
+def reset_after_fork():
+    global worker
+    atexit.unregister(close_worker)
+    worker = None
+
+
 def _send_command(action: str, payload: str) -> None:
     worker = ensure_worker()
     worker.stdin.write(json.dumps({'action': action, 'payload': payload}).encode('utf-8'))