net-print/ippusbxd/files/thread-cleanup.patch

From b2829e3b352234dd2b7ddd683dc61b9c24329090 Mon Sep 17 00:00:00 2001
From: DavieV <davidvalleau@gmail.com>
Date: Tue, 17 Apr 2018 15:41:11 -0700
Subject: [PATCH 4/4] Changing unregister_service_thread to deallocate removed
 thread params

The service_thread_param parameter for a communication thread was being
unallocated before calling to the thread cleanup handler. This sometimes
would result in an error as the entry in the service_threads list would
become invalid causing problems when attempting to unregister threads.

To fix this problem, the thread cleanup handler
(unregister_service_thread()) has been changed to also take care of
freeing the memory associated with the service_thread_param which was
removed.
---
 src/ippusbxd.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/ippusbxd.c b/src/ippusbxd.c
index 5ef5d17..b655eb3 100644
--- a/src/ippusbxd.c
+++ b/src/ippusbxd.c
@@ -143,18 +143,27 @@ static int unregister_service_thread(
   int i;
 
   NOTE("Unregistering thread #%u", thread_num);
+  /* Search |service_threads| for an element with a matching thread number. */
   for (i = 0; i < *num_service_threads; i ++)
     if ((*service_threads)[i]->thread_num == thread_num)
       break;
+
   if (i >= *num_service_threads) {
     ERR("Unregistering thread #%u: Cannot unregister, not found", thread_num);
     return -1;
   }
+
   (*num_service_threads) --;
+  struct service_thread_param *removed_thread = (*service_threads)[i];
+  /* Shift the contents after |removed_thread| down. */
   for (; i < *num_service_threads; i ++)
     (*service_threads)[i] = (*service_threads)[i + 1];
-  *service_threads = realloc(*service_threads,
-			     *num_service_threads * sizeof(void*));
+
+  free(removed_thread);
+
+  *service_threads =
+      realloc(*service_threads, *num_service_threads * sizeof(void *));
+
   if (*num_service_threads == 0)
     *service_threads = NULL;
   else if (*service_threads == NULL) {
@@ -162,6 +171,7 @@ static int unregister_service_thread(
 	thread_num);
     return -1;
   }
+
   return 0;
 }
 
@@ -325,6 +335,8 @@ static void *service_connection(void *params_void)
   if (setup_communication_thread(&service_printer_connection, printer_params))
     goto cleanup;
 
+  pthread_t printer_params_thread_handle = printer_params->thread_handle;
+
   /* This function will run until the socket has been closed. When this function
      returns it means that the communication has been completed. */
   service_socket_connection(params);
@@ -335,8 +347,8 @@ static void *service_connection(void *params_void)
   
   /* Wait for the printer thread to exit. */
   NOTE("Thread #%u: Waiting for thread #%u to complete", thread_num,
-       printer_params->thread_num);
-  if (pthread_join(printer_params->thread_handle, NULL))
+       thread_num + 1);
+  if (pthread_join(printer_params_thread_handle, NULL))
     ERR("Thread #%u: Something went wrong trying to join the printer thread",
         thread_num);
 
@@ -355,7 +367,6 @@ cleanup:
     uds_conn_close(params->uds);
   else
     tcp_conn_close(params->tcp);
-  free(params);
 
   /* Execute clean-up handler. */
   pthread_cleanup_pop(1);
-- 
2.17.0.484.g0c8726318c-goog