libmicrohttpd

commit 7764a946fd1c051dea59b0e3404a371a34319572
parent b3e48b50908ebd754da1fac9cc3b26d567413daa
Author: Evgeny Grin (Karlson2k) <k2k@narod.ru>
Date:   Thu, 16 Mar 2017 17:57:46 +0300

Fixed thread-safety of MHD_get_daemon_info() for MHD_DAEMON_INFO_CURRENT_CONNECTIONS,
Updated MHD_DAEMON_INFO_CURRENT_CONNECTIONS description

Diffstat:
M
src/include/microhttpd.h
 | 
3
+++
M
src/microhttpd/daemon.c
 | 
18
++++++++++++------

2 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/src/include/microhttpd.h b/src/include/microhttpd.h
@@ -1795,6 +1795,9 @@ enum MHD_DaemonInfoType
   /**
    * Request the number of current connections handled by the daemon.
    * No extra arguments should be passed.
+   * Note: when using MHD in external polling mode, this type of request
+   * could be used only when #MHD_run()/#MHD_run_from_select is not
+   * working in other thread at the same time.
    */
   MHD_DAEMON_INFO_CURRENT_CONNECTIONS,
 
diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
@@ -6234,6 +6234,8 @@ MHD_get_daemon_info (struct MHD_Daemon *daemon,
 		     enum MHD_DaemonInfoType info_type,
 		     ...)
 {
+  if (NULL == daemon)
+    return NULL;
   switch (info_type)
     {
     case MHD_DAEMON_INFO_KEY_SIZE:
@@ -6247,16 +6249,20 @@ MHD_get_daemon_info (struct MHD_Daemon *daemon,
       return (const union MHD_DaemonInfo *) &daemon->epoll_fd;
 #endif
     case MHD_DAEMON_INFO_CURRENT_CONNECTIONS:
-      MHD_cleanup_connections (daemon);
-      if (daemon->worker_pool)
+      if (0 == (daemon->options & MHD_USE_INTERNAL_POLLING_THREAD))
+        {
+          /* Assume that MHD_run() in not called in other thread
+           * at the same time. */
+          MHD_cleanup_connections (daemon);
+        }
+      else if (daemon->worker_pool)
         {
-          /* Collect the connection information stored in the workers. */
           unsigned int i;
-
+          /* Collect the connection information stored in the workers. */
           daemon->connections = 0;
-          for (i=0;i<daemon->worker_pool_size;i++)
+          for (i = 0; i < daemon->worker_pool_size; i++)
             {
-              MHD_cleanup_connections (&daemon->worker_pool[i]);
+              /* FIXME: next line is thread-safe only if read is atomic. */
               daemon->connections += daemon->worker_pool[i].connections;
             }
         }