fix unnecessary and potentially problematic use of eready DLL in thread-per-connection mode

4 files changed, 76 insertions, 67 deletions

diff --git a/ChangeLog b/ChangeLog
index c65582d7..402463eb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Mar 15 20:29:34 CET 2016
+        Do not use eready DLL data structure unless
+        we are actually using epoll(). -DD/CG
+
 Fri Feb  5 20:43:11 CET 2016
         Fixed testsuite compile warning on W32.
         Added check test for triggering poll() on
diff --git a/src/include/microhttpd.h b/src/include/microhttpd.h
index c7f23c15..61eebb80 100644
--- a/src/include/microhttpd.h
+++ b/src/include/microhttpd.h
@@ -130,7 +130,7 @@ typedef intptr_t ssize_t;
  * Current version of the library.
  * 0x01093001 = 1.9.30-1.
  */
-#define MHD_VERSION 0x00094802
+#define MHD_VERSION 0x00094803
 
 /**
  * MHD-internal return code for "YES".
diff --git a/src/microhttpd/connection.c b/src/microhttpd/connection.c
index 0a9f9885..dc224588 100644
--- a/src/microhttpd/connection.c
+++ b/src/microhttpd/connection.c
@@ -2709,7 +2709,7 @@ MHD_connection_handle_idle (struct MHD_Connection *connection)
               connection->state = MHD_CONNECTION_NORMAL_BODY_READY;
               /* Buffering for flushable socket was already enabled*/
               if (MHD_NO == socket_flush_possible (connection))
-                socket_start_no_buffering (connection); 
+                socket_start_no_buffering (connection);
 
               break;
             }
@@ -2737,7 +2737,7 @@ MHD_connection_handle_idle (struct MHD_Connection *connection)
               connection->state = MHD_CONNECTION_CHUNKED_BODY_READY;
               /* Buffering for flushable socket was already enabled */
               if (MHD_NO == socket_flush_possible (connection))
-                socket_start_no_buffering (connection); 
+                socket_start_no_buffering (connection);
 
               continue;
             }
@@ -2860,45 +2860,48 @@ MHD_connection_handle_idle (struct MHD_Connection *connection)
     }
   MHD_connection_update_event_loop_info (connection);
 #if EPOLL_SUPPORT
-  switch (connection->event_loop_info)
+  if (0 != (daemon->options & MHD_USE_EPOLL_LINUX_ONLY))
     {
-    case MHD_EVENT_LOOP_INFO_READ:
-      if ( (0 != (connection->epoll_state & MHD_EPOLL_STATE_READ_READY)) &&
-           (0 == (connection->epoll_state & MHD_EPOLL_STATE_SUSPENDED)) &&
-           (0 == (connection->epoll_state & MHD_EPOLL_STATE_IN_EREADY_EDLL)) )
-        {
-          EDLL_insert (daemon->eready_head,
-                       daemon->eready_tail,
-                       connection);
-          connection->epoll_state |= MHD_EPOLL_STATE_IN_EREADY_EDLL;
-        }
-      break;
-    case MHD_EVENT_LOOP_INFO_WRITE:
-      if ( (0 != (connection->epoll_state & MHD_EPOLL_STATE_WRITE_READY)) &&
-           (0 == (connection->epoll_state & MHD_EPOLL_STATE_SUSPENDED)) &&
-           (0 == (connection->epoll_state & MHD_EPOLL_STATE_IN_EREADY_EDLL)) )
-        {
-          EDLL_insert (daemon->eready_head,
-                       daemon->eready_tail,
-                       connection);
-          connection->epoll_state |= MHD_EPOLL_STATE_IN_EREADY_EDLL;
-        }
-      break;
-    case MHD_EVENT_LOOP_INFO_BLOCK:
-      /* we should look at this connection again in the next iteration
-         of the event loop, as we're waiting on the application */
-      if ( (0 == (connection->epoll_state & MHD_EPOLL_STATE_IN_EREADY_EDLL) &&
-           (0 == (connection->epoll_state & MHD_EPOLL_STATE_SUSPENDED))) )
-        {
-          EDLL_insert (daemon->eready_head,
-                       daemon->eready_tail,
-                       connection);
-          connection->epoll_state |= MHD_EPOLL_STATE_IN_EREADY_EDLL;
-        }
-      break;
-    case MHD_EVENT_LOOP_INFO_CLEANUP:
-      /* This connection is finished, nothing left to do */
-      break;
+      switch (connection->event_loop_info)
+        {
+        case MHD_EVENT_LOOP_INFO_READ:
+          if ( (0 != (connection->epoll_state & MHD_EPOLL_STATE_READ_READY)) &&
+               (0 == (connection->epoll_state & MHD_EPOLL_STATE_SUSPENDED)) &&
+               (0 == (connection->epoll_state & MHD_EPOLL_STATE_IN_EREADY_EDLL)) )
+            {
+              EDLL_insert (daemon->eready_head,
+                           daemon->eready_tail,
+                           connection);
+              connection->epoll_state |= MHD_EPOLL_STATE_IN_EREADY_EDLL;
+            }
+          break;
+        case MHD_EVENT_LOOP_INFO_WRITE:
+          if ( (0 != (connection->epoll_state & MHD_EPOLL_STATE_WRITE_READY)) &&
+               (0 == (connection->epoll_state & MHD_EPOLL_STATE_SUSPENDED)) &&
+               (0 == (connection->epoll_state & MHD_EPOLL_STATE_IN_EREADY_EDLL)) )
+            {
+              EDLL_insert (daemon->eready_head,
+                           daemon->eready_tail,
+                           connection);
+              connection->epoll_state |= MHD_EPOLL_STATE_IN_EREADY_EDLL;
+            }
+          break;
+        case MHD_EVENT_LOOP_INFO_BLOCK:
+          /* we should look at this connection again in the next iteration
+             of the event loop, as we're waiting on the application */
+          if ( (0 == (connection->epoll_state & MHD_EPOLL_STATE_IN_EREADY_EDLL) &&
+                (0 == (connection->epoll_state & MHD_EPOLL_STATE_SUSPENDED))) )
+            {
+              EDLL_insert (daemon->eready_head,
+                           daemon->eready_tail,
+                           connection);
+              connection->epoll_state |= MHD_EPOLL_STATE_IN_EREADY_EDLL;
+            }
+          break;
+        case MHD_EVENT_LOOP_INFO_CLEANUP:
+          /* This connection is finished, nothing left to do */
+          break;
+        }
     }
   return MHD_connection_epoll_update_ (connection);
 #else
diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
index bbd7b42d..14786042 100644
--- a/src/microhttpd/daemon.c
+++ b/src/microhttpd/daemon.c
@@ -1,6 +1,6 @@
 /*
   This file is part of libmicrohttpd
-  Copyright (C) 2007-2014 Daniel Pittman and Christian Grothoff
+  Copyright (C) 2007-2016 Daniel Pittman and Christian Grothoff
 
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
@@ -2081,30 +2081,32 @@ MHD_cleanup_connections (struct MHD_Daemon *daemon)
                                    MHD_CONNECTION_NOTIFY_CLOSED);
       MHD_ip_limit_del (daemon, pos->addr, pos->addr_len);
 #if EPOLL_SUPPORT
-      if (0 != (pos->epoll_state & MHD_EPOLL_STATE_IN_EREADY_EDLL))
-        {
-          EDLL_remove (daemon->eready_head,
-                       daemon->eready_tail,
-                       pos);
-          pos->epoll_state &= ~MHD_EPOLL_STATE_IN_EREADY_EDLL;
-        }
-      if ( (0 != (daemon->options & MHD_USE_EPOLL_LINUX_ONLY)) &&
-           (MHD_INVALID_SOCKET != daemon->epoll_fd) &&
-           (0 != (pos->epoll_state & MHD_EPOLL_STATE_IN_EPOLL_SET)) )
-        {
-          /* epoll documentation suggests that closing a FD
-             automatically removes it from the epoll set; however,
-             this is not true as if we fail to do manually remove it,
-             we are still seeing an event for this fd in epoll,
-             causing grief (use-after-free...) --- at least on my
-             system. */
-          if (0 != epoll_ctl (daemon->epoll_fd,
-                              EPOLL_CTL_DEL,
-                              pos->socket_fd,
-                              NULL))
-            MHD_PANIC ("Failed to remove FD from epoll set\n");
-          pos->epoll_state &= ~MHD_EPOLL_STATE_IN_EPOLL_SET;
-        }
+      if (0 != (daemon->options & MHD_USE_EPOLL_LINUX_ONLY))
+        {
+          if (0 != (pos->epoll_state & MHD_EPOLL_STATE_IN_EREADY_EDLL))
+            {
+              EDLL_remove (daemon->eready_head,
+                           daemon->eready_tail,
+                           pos);
+              pos->epoll_state &= ~MHD_EPOLL_STATE_IN_EREADY_EDLL;
+            }
+          if ( (MHD_INVALID_SOCKET != daemon->epoll_fd) &&
+               (0 != (pos->epoll_state & MHD_EPOLL_STATE_IN_EPOLL_SET)) )
+            {
+              /* epoll documentation suggests that closing a FD
+                 automatically removes it from the epoll set; however,
+                 this is not true as if we fail to do manually remove it,
+                 we are still seeing an event for this fd in epoll,
+                 causing grief (use-after-free...) --- at least on my
+                 system. */
+              if (0 != epoll_ctl (daemon->epoll_fd,
+                                  EPOLL_CTL_DEL,
+                                  pos->socket_fd,
+                                  NULL))
+                MHD_PANIC ("Failed to remove FD from epoll set\n");
+              pos->epoll_state &= ~MHD_EPOLL_STATE_IN_EPOLL_SET;
+            }
+        }
 #endif
       if (NULL != pos->response)
         {
@@ -3766,7 +3768,7 @@ MHD_start_daemon_va (unsigned int flags,
   if (0 == (flags & (MHD_USE_SELECT_INTERNALLY | MHD_USE_THREAD_PER_CONNECTION)))
     use_pipe = 0; /* useless if we are using 'external' select */
   if (use_pipe)
-  { 
+  {
     if (0 != MHD_pipe_ (daemon->wpipe))
     {
 #ifdef HAVE_MESSAGES