Fix an issue on pcscd exit

When pcscd exits we must first terminate any client thread on the
server side before closing the reader threads.
This is to prevent a client thread to access a now deactivated reader.

The error was:
^C00250854 [140433941325504] pcscdaemon.c:192:signal_thread() Received signal: 2
00000036 [140433941325504] pcscdaemon.c:226:signal_thread() Preparing for suicide
[...readers are stopped here...]
00000042 [140433995138368] pcscdaemon.c:809:at_exit() cleaning /run/pcscd
[...but we get a new request from a client...]
00000016 [140433906050752] winscard_svc.c:384:ContextThread() Received command: CMD_WAIT_READER_STATE_CHANGE from client 12
==================
WARNING: ThreadSanitizer: use of an invalid mutex (e.g. uninitialized or destroyed) (pid=62372)
    #0 pthread_mutex_lock <null> (pcscd+0x71ada) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #1 EHRegisterClientForEvent PCSC/src/eventhandler.c:68:8 (pcscd+0xe5b2a) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #2 ContextThread PCSC/src/winscard_svc.c:446:5 (pcscd+0xe5b2a)
    #3 __tsan_thread_start_func <null> (pcscd+0x53d66) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)

  Location is global 'ClientsWaitingForEvent_lock' of size 40 at 0x556bd69d67c8 (pcscd+0x14977c8)

  Mutex M0 (0x556bd69d67c8) created at:
    [failed to restore the stack]

SUMMARY: ThreadSanitizer: use of an invalid mutex (e.g. uninitialized or destroyed) (PCSC/src/pcscd+0x71ada) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914) in __interceptor_pthread_mutex_lock
==================
==================
WARNING: ThreadSanitizer: heap-use-after-free (pid=62372)
  Read of size 8 at 0x7b0c00000060 by thread T5:
    #0 list_insert_at PCSC/src/simclist.c:503:16 (pcscd+0xdea60) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #1 list_append PCSC/src/simclist.c:397:12 (pcscd+0xdea60)
    #2 EHRegisterClientForEvent PCSC/src/eventhandler.c:70:8 (pcscd+0xe5b39) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #3 ContextThread PCSC/src/winscard_svc.c:446:5 (pcscd+0xe5b39)
    #4 EHRegisterClientForEvent PCSC/src/eventhandler.c:70:8 (pcscd+0xe5b39) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #5 ContextThread PCSC/src/winscard_svc.c:446:5 (pcscd+0xe5b39)
    #6 __tsan_thread_start_func <null> (pcscd+0x53d66) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)

  Previous write of size 8 at 0x7b0c00000060 by main thread:
    #0 free <null> (pcscd+0x52c84) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #1 list_destroy PCSC/src/simclist.c:317:5 (pcscd+0xde590) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #2 EHDeinitializeEventStructures PCSC/src/eventhandler.c:152:2 (pcscd+0xd6866) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #3 SVCServiceRunLoop PCSC/src/pcscdaemon.c:124:4 (pcscd+0xd9649) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #4 main PCSC/src/pcscdaemon.c:801:2 (pcscd+0xd88e0) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)

  Thread T5 (tid=62379, running) created by main thread at:
    #0 pthread_create <null> (pcscd+0x53dfd) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #1 ThreadCreate PCSC/src/utils.c:184:8 (pcscd+0xe3c7b) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #2 CreateContextThread PCSC/src/winscard_svc.c:258:7 (pcscd+0xd931e) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #3 SVCServiceRunLoop PCSC/src/pcscdaemon.c:133:9 (pcscd+0xd931e)
    #4 main PCSC/src/pcscdaemon.c:801:2 (pcscd+0xd88e0) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)
    #5 main PCSC/src/pcscdaemon.c:801:2 (pcscd+0xd88e0) (BuildId: 1bcd3f8a880d8c656c6e6bbe77b504b573d68914)

SUMMARY: ThreadSanitizer: heap-use-after-free PCSC/src/simclist.c:503:16 in list_insert_at
==================
etc..

src/pcscdaemon.c

@@ -116,10 +116,12 @@ static void SVCServiceRunLoop(void)
 #endif
  (void)SYS_Sleep(1);
 
+ /* stop all the clients */
+ ContextsDeinitialize();
+
  /* now stop all the drivers */
  RFCleanupReaders();
  EHDeinitializeEventStructures();
- ContextsDeinitialize();
  at_exit();
  }
 

src/winscard_svc.c

@@ -155,8 +155,25 @@ void ContextsDeinitialize(void)
  (void)listSize;
 #endif
  Log2(PCSC_LOG_DEBUG, "remaining threads: %d", listSize);
- /* This is currently a no-op. It should terminate the threads properly. */
 
+ /* terminate all the client threads */
+ int rv = list_iterator_start(&contextsList);
+ if (0 == rv)
+ Log1(PCSC_LOG_ERROR, "list_iterator_start failed");
+ else
+ {
+ while (list_iterator_hasnext(&contextsList))
+ {
+ SCONTEXT * elt = list_iterator_next(&contextsList);
+ Log3(PCSC_LOG_DEBUG, "Cancel dwClientID=%d hContext: %p",
+ elt->dwClientID, elt);
+ EHTryToUnregisterClientForEvent(elt->dwClientID);
+ close(elt->dwClientID);
+ Log2(PCSC_LOG_DEBUG, "Waiting client: %d", elt->dwClientID);
+ pthread_join(elt->pthThread, NULL);
+ Log2(PCSC_LOG_INFO, "Client %d terminated", elt->dwClientID);
+ }
+ }
  list_destroy(&contextsList);
  (void)pthread_mutex_unlock(&contextsList_lock);
 }