[core] no graceful-restart-bg on OpenBSD, NetBSD

disable server.graceful-restart-bg on OpenBSD and NetBSD

kqueue is not inherited across fork, and OpenBSD and NetBSD do not
implement rfork() (implemented on FreeBSD and DragonFly)

lighttpd has not implemented rebuilding the kqueues after fork,
so server.graceful-restart-bg is disabled on OpenBSD and NetBSD.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/server.c b/src/server.c
index 1acac9bf..83c0241f 100644
--- a/src/server.c
+++ b/src/server.c
@@ -841,7 +841,26 @@ static int server_graceful_state_bg (server *srv) {
      *   platforms to achieve the same:
      *   https://stackoverflow.com/questions/1023306/finding-current-executables-path-without-proc-self-exe
      */
+  #if defined(HAVE_KQUEUE)
+   #if defined(__FreeBSD__) || defined(__DragonFly__)
+    /*(must *exclude* rfork RFFDG flag for kqueue to work across rfork)*/
+    pid_t pid = rfork(RFPROC);
+   #else
+    pid_t pid = -1;
+    if (pid < 0) {
+        /* kqueue is not inherited across fork
+         * future: fdevent kqueue and stat_cache kqueue would need to be closed,
+         *         re-opened, and active fds re-registered.  Not current done.
+         *         Need to create some routines like fdevent_reinit_after_fork*/
+        log_error(srv->errh, __FILE__, __LINE__,
+          "server.graceful-restart-bg ignored on OpenBSD and NetBSD "
+          "due to limitation in kqueue inheritance and lacking rfork");
+        return 0;
+    }
+   #endif
+  #else
     pid_t pid = fork();
+  #endif
     if (pid) { /* original process */
         if (pid < 0) return 0;
         network_socket_activation_to_env(srv);