cups-thread.c.patch

--- src/cups/thread.c	2020-07-05 13:16:28.060000000 +0000
+++ src-mod/cups/thread.c	2020-07-05 13:18:17.010000000 +0000
@@ -145,6 +145,40 @@
   pthread_rwlock_unlock(rwlock);
 }
 
+/*
+ * '_cupsThreadAndroidSignalHandler()' - Wrapper around pthread_exit(0) to be called from a signal handler
+ */
+
+void
+_cupsThreadAndroidSignalHandler(int sig)
+{
+  pthread_exit(0);
+}
+
+/*
+ * '_cupsThreadAndroidWrapper()' - Function for wrapping a thread start with a signal handler for cancellation
+ */
+
+void *
+_cupsThreadAndroidWrapper(void *arg)
+{
+  _cups_wrapped_thread_func_t *wrapped = (_cups_wrapped_thread_func_t*) arg;
+  
+  struct sigaction actions;
+  memset(&actions, 0, sizeof(actions));
+  sigemptyset(&actions.sa_mask);
+  actions.sa_flags = 0;
+  actions.sa_handler = _cupsThreadAndroidSignalHandler;
+  sigaction(SIGUSR2, &actions, NULL);
+  
+  _cups_thread_func_t func = wrapped->func;
+  void *func_arg = wrapped->arg;
+
+  free(wrapped);
+
+  return (*func)(func_arg);
+}
+
 
 /*
  * '_cupsThreadCancel()' - Cancel (kill) a thread.
@@ -153,7 +187,7 @@
 void
 _cupsThreadCancel(_cups_thread_t thread)/* I - Thread ID */
 {
-  pthread_cancel(thread);
+  pthread_kill(thread, SIGUSR2);
 }
 
 
@@ -168,7 +202,11 @@
 {
   pthread_t thread;
 
-  if (pthread_create(&thread, NULL, (void *(*)(void *))func, arg))
+  _cups_wrapped_thread_func_t *wrapped = malloc(sizeof(_cups_wrapped_thread_func_t));
+  wrapped->func = func;
+  wrapped->arg = arg;
+
+  if (pthread_create(&thread, NULL, _cupsThreadAndroidWrapper, wrapped))
     return (0);
   else
     return (thread);