[GNUnet-SVN] r37175 - in libmicrohttpd: . src/include src/microhttpd

[gnunet]

Author: grothoff
Date: 2016-05-15 12:20:04 +0200 (Sun, 15 May 2016)
New Revision: 37175

Modified:
   libmicrohttpd/ChangeLog
   libmicrohttpd/src/include/microhttpd.h
   libmicrohttpd/src/microhttpd/daemon.c
   libmicrohttpd/src/microhttpd/internal.h
Log:
handle EMFILE, ENFILE, ENOBUF on accept

Modified: libmicrohttpd/ChangeLog
===================================================================
--- libmicrohttpd/ChangeLog     2016-05-15 09:56:55 UTC (rev 37174)
+++ libmicrohttpd/ChangeLog     2016-05-15 10:20:04 UTC (rev 37175)
@@ -1,3 +1,7 @@
+Sun May 15 12:17:25 CEST 2016
+       Fix handling system or process resource limit exhaustion upon
+       accept(). -CG/CP
+
 Thu May 12 08:42:19 CEST 2016
        Fix handling of partial writes in MHD_USE_EPOLL_LINUX_ONLY; only
        consider sockets returning EAGAIN as unready. -CG/CP

Modified: libmicrohttpd/src/include/microhttpd.h
===================================================================
--- libmicrohttpd/src/include/microhttpd.h      2016-05-15 09:56:55 UTC (rev 
37174)
+++ libmicrohttpd/src/include/microhttpd.h      2016-05-15 10:20:04 UTC (rev 
37175)
@@ -130,7 +130,7 @@
  * Current version of the library.
  * 0x01093001 = 1.9.30-1.
  */
-#define MHD_VERSION 0x00094901
+#define MHD_VERSION 0x00094902
 
 /**
  * MHD-internal return code for "YES".

Modified: libmicrohttpd/src/microhttpd/daemon.c
===================================================================
--- libmicrohttpd/src/microhttpd/daemon.c       2016-05-15 09:56:55 UTC (rev 
37174)
+++ libmicrohttpd/src/microhttpd/daemon.c       2016-05-15 10:20:04 UTC (rev 
37175)
@@ -2085,6 +2085,28 @@
            MHD_PANIC ("close failed\n");
           /* just in case */
         }
+      if ( (EMFILE == err) ||
+           (ENFILE == err) ||
+           (ENOMEM == err) ||
+           (ENOBUFS == err) )
+        {
+          /* system/process out of resources */
+          if (0 == daemon->connections)
+            {
+              /* Not setting 'at_limit' flag, as there is no way it
+                 would ever be cleared.  Instead trying to produce
+                 bit fat ugly warning. */
+              MHD_DLOG (daemon,
+                        "Hit process or system resource limit at FIRST 
connection. This is really bad as there is no sane way to proceed. Will try 
busy waiting for system resources to become magically available.\n");
+            }
+          else
+            {
+              daemon->at_limit = MHD_YES;
+              MHD_DLOG (daemon,
+                        "Hit process or system resource limit at %u 
connections, temporarily suspending accept(). Consider setting a lower 
MHD_OPTION_CONNECTION_LIMIT.\n",
+                        (unsigned int) daemon->connections);
+            }
+        }
       return MHD_NO;
     }
 #if !defined(USE_ACCEPT4)
@@ -2142,6 +2164,7 @@
        gnutls_deinit (pos->tls_session);
 #endif
       daemon->connections--;
+      daemon->at_limit = MHD_NO;
       if (NULL != daemon->notify_connection)
         daemon->notify_connection (daemon->notify_connection_cls,
                                    pos,
@@ -2420,9 +2443,10 @@
          we do not miss the shutdown, so only do this
          optimization if we have a shutdown signaling
          pipe. */
-      if ( (MHD_INVALID_SOCKET != daemon->socket_fd) &&
-           (daemon->connections == daemon->connection_limit) &&
-           (0 != (daemon->options & MHD_USE_PIPE_FOR_SHUTDOWN)) )
+      if ( ( (MHD_INVALID_SOCKET != daemon->socket_fd) &&
+             (daemon->connections == daemon->connection_limit) &&
+             (0 != (daemon->options & MHD_USE_PIPE_FOR_SHUTDOWN)) ) ||
+           (MHD_YES == daemon->at_limit) )
         FD_CLR (daemon->socket_fd, &rs);
     }
   else
@@ -2558,7 +2582,8 @@
     poll_server = 0;
     poll_listen = -1;
     if ( (MHD_INVALID_SOCKET != daemon->socket_fd) &&
-        (daemon->connections < daemon->connection_limit) )
+        (daemon->connections < daemon->connection_limit) &&
+         (MHD_NO == daemon->at_limit) )
       {
        /* only listen if we are not at the connection limit */
        p[poll_server].fd = daemon->socket_fd;
@@ -2794,7 +2819,8 @@
     return MHD_NO;
   if ( (MHD_INVALID_SOCKET != daemon->socket_fd) &&
        (daemon->connections < daemon->connection_limit) &&
-       (MHD_NO == daemon->listen_socket_in_epoll) )
+       (MHD_NO == daemon->listen_socket_in_epoll) &&
+       (MHD_NO == daemon->at_limit) )
     {
       event.events = EPOLLIN;
       event.data.ptr = daemon;
@@ -2812,8 +2838,9 @@
        }
       daemon->listen_socket_in_epoll = MHD_YES;
     }
-  if ( (MHD_YES == daemon->listen_socket_in_epoll) &&
-       (daemon->connections == daemon->connection_limit) )
+  if ( ( (MHD_YES == daemon->listen_socket_in_epoll) &&
+         (daemon->connections == daemon->connection_limit) ) ||
+       (MHD_YES == daemon->at_limit) )
     {
       /* we're at the connection limit, disable listen socket
         for event loop for now */
@@ -2912,7 +2939,8 @@
              series_length = 0;
              while ( (MHD_YES == MHD_accept_connection (daemon)) &&
                      (daemon->connections < daemon->connection_limit) &&
-                     (series_length < 128) )
+                     (series_length < 128) &&
+                      (MHD_NO == daemon->at_limit) )
                 series_length++;
            }
        }

Modified: libmicrohttpd/src/microhttpd/internal.h
===================================================================
--- libmicrohttpd/src/microhttpd/internal.h     2016-05-15 09:56:55 UTC (rev 
37174)
+++ libmicrohttpd/src/microhttpd/internal.h     2016-05-15 10:20:04 UTC (rev 
37175)
@@ -1164,6 +1164,15 @@
    */
   int shutdown;
 
+  /**
+   * Did we hit some system or process-wide resource limit while
+   * trying to accept() the last time? If so, we don't accept new
+   * connections until we close an existing one.  This effectively
+   * temporarily lowers the "connection_limit" to the current
+   * number of connections.
+   */
+  int at_limit;
+
   /*
    * Do we need to process resuming connections?
    */